diff options
| author | cvs2svn <cvs2svn@FreeBSD.org> | 2000-05-27 02:25:29 +0000 |
|---|---|---|
| committer | cvs2svn <cvs2svn@FreeBSD.org> | 2000-05-27 02:25:29 +0000 |
| commit | 9bf6bc8933de87c41c8245b553f777a8bbdcab7f (patch) | |
| tree | 6bfb073c78cbdfdc5ca8e0b975d84e6be75f2c42 /contrib/gcc/combine.c | |
| parent | c6d2f3514a57725780ace95a120243815e145505 (diff) | |
Diffstat (limited to 'contrib/gcc/combine.c')
| -rw-r--r-- | contrib/gcc/combine.c | 11991 |
1 files changed, 0 insertions, 11991 deletions
diff --git a/contrib/gcc/combine.c b/contrib/gcc/combine.c deleted file mode 100644 index 57b2e8619bc63..0000000000000 --- a/contrib/gcc/combine.c +++ /dev/null @@ -1,11991 +0,0 @@ -/* Optimize by combining instructions for GNU compiler. - Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc. - -This file is part of GNU CC. - -GNU CC is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. - -GNU CC is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. - -You should have received a copy of the GNU General Public License -along with GNU CC; see the file COPYING. If not, write to -the Free Software Foundation, 59 Temple Place - Suite 330, -Boston, MA 02111-1307, USA. */ - - -/* This module is essentially the "combiner" phase of the U. of Arizona - Portable Optimizer, but redone to work on our list-structured - representation for RTL instead of their string representation. - - The LOG_LINKS of each insn identify the most recent assignment - to each REG used in the insn. It is a list of previous insns, - each of which contains a SET for a REG that is used in this insn - and not used or set in between. LOG_LINKs never cross basic blocks. - They were set up by the preceding pass (lifetime analysis). - - We try to combine each pair of insns joined by a logical link. - We also try to combine triples of insns A, B and C when - C has a link back to B and B has a link back to A. - - LOG_LINKS does not have links for use of the CC0. They don't - need to, because the insn that sets the CC0 is always immediately - before the insn that tests it. So we always regard a branch - insn as having a logical link to the preceding insn. The same is true - for an insn explicitly using CC0. - - We check (with use_crosses_set_p) to avoid combining in such a way - as to move a computation to a place where its value would be different. - - Combination is done by mathematically substituting the previous - insn(s) values for the regs they set into the expressions in - the later insns that refer to these regs. If the result is a valid insn - for our target machine, according to the machine description, - we install it, delete the earlier insns, and update the data flow - information (LOG_LINKS and REG_NOTES) for what we did. - - There are a few exceptions where the dataflow information created by - flow.c aren't completely updated: - - - reg_live_length is not updated - - reg_n_refs is not adjusted in the rare case when a register is - no longer required in a computation - - there are extremely rare cases (see distribute_regnotes) when a - REG_DEAD note is lost - - a LOG_LINKS entry that refers to an insn with multiple SETs may be - removed because there is no way to know which register it was - linking - - To simplify substitution, we combine only when the earlier insn(s) - consist of only a single assignment. To simplify updating afterward, - we never combine when a subroutine call appears in the middle. - - Since we do not represent assignments to CC0 explicitly except when that - is all an insn does, there is no LOG_LINKS entry in an insn that uses - the condition code for the insn that set the condition code. - Fortunately, these two insns must be consecutive. - Therefore, every JUMP_INSN is taken to have an implicit logical link - to the preceding insn. This is not quite right, since non-jumps can - also use the condition code; but in practice such insns would not - combine anyway. */ - -#include "config.h" -#include "system.h" -#include "rtl.h" /* stdio.h must precede rtl.h for FFS. */ -#include "flags.h" -#include "regs.h" -#include "hard-reg-set.h" -#include "basic-block.h" -#include "insn-config.h" -/* Include expr.h after insn-config.h so we get HAVE_conditional_move. */ -#include "expr.h" -#include "insn-flags.h" -#include "insn-codes.h" -#include "insn-attr.h" -#include "recog.h" -#include "real.h" -#include "toplev.h" - -/* It is not safe to use ordinary gen_lowpart in combine. - Use gen_lowpart_for_combine instead. See comments there. */ -#define gen_lowpart dont_use_gen_lowpart_you_dummy - -/* Number of attempts to combine instructions in this function. */ - -static int combine_attempts; - -/* Number of attempts that got as far as substitution in this function. */ - -static int combine_merges; - -/* Number of instructions combined with added SETs in this function. */ - -static int combine_extras; - -/* Number of instructions combined in this function. */ - -static int combine_successes; - -/* Totals over entire compilation. */ - -static int total_attempts, total_merges, total_extras, total_successes; - -/* Define a default value for REVERSIBLE_CC_MODE. - We can never assume that a condition code mode is safe to reverse unless - the md tells us so. */ -#ifndef REVERSIBLE_CC_MODE -#define REVERSIBLE_CC_MODE(MODE) 0 -#endif - -/* Vector mapping INSN_UIDs to cuids. - The cuids are like uids but increase monotonically always. - Combine always uses cuids so that it can compare them. - But actually renumbering the uids, which we used to do, - proves to be a bad idea because it makes it hard to compare - the dumps produced by earlier passes with those from later passes. */ - -static int *uid_cuid; -static int max_uid_cuid; - -/* Get the cuid of an insn. */ - -#define INSN_CUID(INSN) \ -(INSN_UID (INSN) > max_uid_cuid ? insn_cuid (INSN) : uid_cuid[INSN_UID (INSN)]) - -/* Maximum register number, which is the size of the tables below. */ - -static int combine_max_regno; - -/* Record last point of death of (hard or pseudo) register n. */ - -static rtx *reg_last_death; - -/* Record last point of modification of (hard or pseudo) register n. */ - -static rtx *reg_last_set; - -/* Record the cuid of the last insn that invalidated memory - (anything that writes memory, and subroutine calls, but not pushes). */ - -static int mem_last_set; - -/* Record the cuid of the last CALL_INSN - so we can tell whether a potential combination crosses any calls. */ - -static int last_call_cuid; - -/* When `subst' is called, this is the insn that is being modified - (by combining in a previous insn). The PATTERN of this insn - is still the old pattern partially modified and it should not be - looked at, but this may be used to examine the successors of the insn - to judge whether a simplification is valid. */ - -static rtx subst_insn; - -/* This is an insn that belongs before subst_insn, but is not currently - on the insn chain. */ - -static rtx subst_prev_insn; - -/* This is the lowest CUID that `subst' is currently dealing with. - get_last_value will not return a value if the register was set at or - after this CUID. If not for this mechanism, we could get confused if - I2 or I1 in try_combine were an insn that used the old value of a register - to obtain a new value. In that case, we might erroneously get the - new value of the register when we wanted the old one. */ - -static int subst_low_cuid; - -/* This contains any hard registers that are used in newpat; reg_dead_at_p - must consider all these registers to be always live. */ - -static HARD_REG_SET newpat_used_regs; - -/* This is an insn to which a LOG_LINKS entry has been added. If this - insn is the earlier than I2 or I3, combine should rescan starting at - that location. */ - -static rtx added_links_insn; - -/* Basic block number of the block in which we are performing combines. */ -static int this_basic_block; - -/* The next group of arrays allows the recording of the last value assigned - to (hard or pseudo) register n. We use this information to see if a - operation being processed is redundant given a prior operation performed - on the register. For example, an `and' with a constant is redundant if - all the zero bits are already known to be turned off. - - We use an approach similar to that used by cse, but change it in the - following ways: - - (1) We do not want to reinitialize at each label. - (2) It is useful, but not critical, to know the actual value assigned - to a register. Often just its form is helpful. - - Therefore, we maintain the following arrays: - - reg_last_set_value the last value assigned - reg_last_set_label records the value of label_tick when the - register was assigned - reg_last_set_table_tick records the value of label_tick when a - value using the register is assigned - reg_last_set_invalid set to non-zero when it is not valid - to use the value of this register in some - register's value - - To understand the usage of these tables, it is important to understand - the distinction between the value in reg_last_set_value being valid - and the register being validly contained in some other expression in the - table. - - Entry I in reg_last_set_value is valid if it is non-zero, and either - reg_n_sets[i] is 1 or reg_last_set_label[i] == label_tick. - - Register I may validly appear in any expression returned for the value - of another register if reg_n_sets[i] is 1. It may also appear in the - value for register J if reg_last_set_label[i] < reg_last_set_label[j] or - reg_last_set_invalid[j] is zero. - - If an expression is found in the table containing a register which may - not validly appear in an expression, the register is replaced by - something that won't match, (clobber (const_int 0)). - - reg_last_set_invalid[i] is set non-zero when register I is being assigned - to and reg_last_set_table_tick[i] == label_tick. */ - -/* Record last value assigned to (hard or pseudo) register n. */ - -static rtx *reg_last_set_value; - -/* Record the value of label_tick when the value for register n is placed in - reg_last_set_value[n]. */ - -static int *reg_last_set_label; - -/* Record the value of label_tick when an expression involving register n - is placed in reg_last_set_value. */ - -static int *reg_last_set_table_tick; - -/* Set non-zero if references to register n in expressions should not be - used. */ - -static char *reg_last_set_invalid; - -/* Incremented for each label. */ - -static int label_tick; - -/* Some registers that are set more than once and used in more than one - basic block are nevertheless always set in similar ways. For example, - a QImode register may be loaded from memory in two places on a machine - where byte loads zero extend. - - We record in the following array what we know about the nonzero - bits of a register, specifically which bits are known to be zero. - - If an entry is zero, it means that we don't know anything special. */ - -static unsigned HOST_WIDE_INT *reg_nonzero_bits; - -/* Mode used to compute significance in reg_nonzero_bits. It is the largest - integer mode that can fit in HOST_BITS_PER_WIDE_INT. */ - -static enum machine_mode nonzero_bits_mode; - -/* Nonzero if we know that a register has some leading bits that are always - equal to the sign bit. */ - -static char *reg_sign_bit_copies; - -/* Nonzero when reg_nonzero_bits and reg_sign_bit_copies can be safely used. - It is zero while computing them and after combine has completed. This - former test prevents propagating values based on previously set values, - which can be incorrect if a variable is modified in a loop. */ - -static int nonzero_sign_valid; - -/* These arrays are maintained in parallel with reg_last_set_value - and are used to store the mode in which the register was last set, - the bits that were known to be zero when it was last set, and the - number of sign bits copies it was known to have when it was last set. */ - -static enum machine_mode *reg_last_set_mode; -static unsigned HOST_WIDE_INT *reg_last_set_nonzero_bits; -static char *reg_last_set_sign_bit_copies; - -/* Record one modification to rtl structure - to be undone by storing old_contents into *where. - is_int is 1 if the contents are an int. */ - -struct undo -{ - struct undo *next; - int is_int; - union {rtx r; int i;} old_contents; - union {rtx *r; int *i;} where; -}; - -/* Record a bunch of changes to be undone, up to MAX_UNDO of them. - num_undo says how many are currently recorded. - - storage is nonzero if we must undo the allocation of new storage. - The value of storage is what to pass to obfree. - - other_insn is nonzero if we have modified some other insn in the process - of working on subst_insn. It must be verified too. - - previous_undos is the value of undobuf.undos when we started processing - this substitution. This will prevent gen_rtx_combine from re-used a piece - from the previous expression. Doing so can produce circular rtl - structures. */ - -struct undobuf -{ - char *storage; - struct undo *undos; - struct undo *frees; - struct undo *previous_undos; - rtx other_insn; -}; - -static struct undobuf undobuf; - -/* Substitute NEWVAL, an rtx expression, into INTO, a place in some - insn. The substitution can be undone by undo_all. If INTO is already - set to NEWVAL, do not record this change. Because computing NEWVAL might - also call SUBST, we have to compute it before we put anything into - the undo table. */ - -#define SUBST(INTO, NEWVAL) \ - do { rtx _new = (NEWVAL); \ - struct undo *_buf; \ - \ - if (undobuf.frees) \ - _buf = undobuf.frees, undobuf.frees = _buf->next; \ - else \ - _buf = (struct undo *) xmalloc (sizeof (struct undo)); \ - \ - _buf->is_int = 0; \ - _buf->where.r = &INTO; \ - _buf->old_contents.r = INTO; \ - INTO = _new; \ - if (_buf->old_contents.r == INTO) \ - _buf->next = undobuf.frees, undobuf.frees = _buf; \ - else \ - _buf->next = undobuf.undos, undobuf.undos = _buf; \ - } while (0) - -/* Similar to SUBST, but NEWVAL is an int expression. Note that substitution - for the value of a HOST_WIDE_INT value (including CONST_INT) is - not safe. */ - -#define SUBST_INT(INTO, NEWVAL) \ - do { struct undo *_buf; \ - \ - if (undobuf.frees) \ - _buf = undobuf.frees, undobuf.frees = _buf->next; \ - else \ - _buf = (struct undo *) xmalloc (sizeof (struct undo)); \ - \ - _buf->is_int = 1; \ - _buf->where.i = (int *) &INTO; \ - _buf->old_contents.i = INTO; \ - INTO = NEWVAL; \ - if (_buf->old_contents.i == INTO) \ - _buf->next = undobuf.frees, undobuf.frees = _buf; \ - else \ - _buf->next = undobuf.undos, undobuf.undos = _buf; \ - } while (0) - -/* Number of times the pseudo being substituted for - was found and replaced. */ - -static int n_occurrences; - -static void init_reg_last_arrays PROTO((void)); -static void setup_incoming_promotions PROTO((void)); -static void set_nonzero_bits_and_sign_copies PROTO((rtx, rtx)); -static int can_combine_p PROTO((rtx, rtx, rtx, rtx, rtx *, rtx *)); -static int sets_function_arg_p PROTO((rtx)); -static int combinable_i3pat PROTO((rtx, rtx *, rtx, rtx, int, rtx *)); -static rtx try_combine PROTO((rtx, rtx, rtx)); -static void undo_all PROTO((void)); -static rtx *find_split_point PROTO((rtx *, rtx)); -static rtx subst PROTO((rtx, rtx, rtx, int, int)); -static rtx simplify_rtx PROTO((rtx, enum machine_mode, int, int)); -static rtx simplify_if_then_else PROTO((rtx)); -static rtx simplify_set PROTO((rtx)); -static rtx simplify_logical PROTO((rtx, int)); -static rtx expand_compound_operation PROTO((rtx)); -static rtx expand_field_assignment PROTO((rtx)); -static rtx make_extraction PROTO((enum machine_mode, rtx, int, rtx, int, - int, int, int)); -static rtx extract_left_shift PROTO((rtx, int)); -static rtx make_compound_operation PROTO((rtx, enum rtx_code)); -static int get_pos_from_mask PROTO((unsigned HOST_WIDE_INT, int *)); -static rtx force_to_mode PROTO((rtx, enum machine_mode, - unsigned HOST_WIDE_INT, rtx, int)); -static rtx if_then_else_cond PROTO((rtx, rtx *, rtx *)); -static rtx known_cond PROTO((rtx, enum rtx_code, rtx, rtx)); -static int rtx_equal_for_field_assignment_p PROTO((rtx, rtx)); -static rtx make_field_assignment PROTO((rtx)); -static rtx apply_distributive_law PROTO((rtx)); -static rtx simplify_and_const_int PROTO((rtx, enum machine_mode, rtx, - unsigned HOST_WIDE_INT)); -static unsigned HOST_WIDE_INT nonzero_bits PROTO((rtx, enum machine_mode)); -static int num_sign_bit_copies PROTO((rtx, enum machine_mode)); -static int merge_outer_ops PROTO((enum rtx_code *, HOST_WIDE_INT *, - enum rtx_code, HOST_WIDE_INT, - enum machine_mode, int *)); -static rtx simplify_shift_const PROTO((rtx, enum rtx_code, enum machine_mode, - rtx, int)); -static int recog_for_combine PROTO((rtx *, rtx, rtx *)); -static rtx gen_lowpart_for_combine PROTO((enum machine_mode, rtx)); -static rtx gen_rtx_combine PVPROTO((enum rtx_code code, enum machine_mode mode, - ...)); -static rtx gen_binary PROTO((enum rtx_code, enum machine_mode, - rtx, rtx)); -static rtx gen_unary PROTO((enum rtx_code, enum machine_mode, - enum machine_mode, rtx)); -static enum rtx_code simplify_comparison PROTO((enum rtx_code, rtx *, rtx *)); -static int reversible_comparison_p PROTO((rtx)); -static void update_table_tick PROTO((rtx)); -static void record_value_for_reg PROTO((rtx, rtx, rtx)); -static void record_dead_and_set_regs_1 PROTO((rtx, rtx)); -static void record_dead_and_set_regs PROTO((rtx)); -static int get_last_value_validate PROTO((rtx *, rtx, int, int)); -static rtx get_last_value PROTO((rtx)); -static int use_crosses_set_p PROTO((rtx, int)); -static void reg_dead_at_p_1 PROTO((rtx, rtx)); -static int reg_dead_at_p PROTO((rtx, rtx)); -static void move_deaths PROTO((rtx, rtx, int, rtx, rtx *)); -static int reg_bitfield_target_p PROTO((rtx, rtx)); -static void distribute_notes PROTO((rtx, rtx, rtx, rtx, rtx, rtx)); -static void distribute_links PROTO((rtx)); -static void mark_used_regs_combine PROTO((rtx)); -static int insn_cuid PROTO((rtx)); - -/* Main entry point for combiner. F is the first insn of the function. - NREGS is the first unused pseudo-reg number. */ - -void -combine_instructions (f, nregs) - rtx f; - int nregs; -{ - register rtx insn, next; -#ifdef HAVE_cc0 - register rtx prev; -#endif - register int i; - register rtx links, nextlinks; - - combine_attempts = 0; - combine_merges = 0; - combine_extras = 0; - combine_successes = 0; - undobuf.undos = undobuf.previous_undos = 0; - - combine_max_regno = nregs; - - reg_nonzero_bits - = (unsigned HOST_WIDE_INT *) alloca (nregs * sizeof (HOST_WIDE_INT)); - reg_sign_bit_copies = (char *) alloca (nregs * sizeof (char)); - - bzero ((char *) reg_nonzero_bits, nregs * sizeof (HOST_WIDE_INT)); - bzero (reg_sign_bit_copies, nregs * sizeof (char)); - - reg_last_death = (rtx *) alloca (nregs * sizeof (rtx)); - reg_last_set = (rtx *) alloca (nregs * sizeof (rtx)); - reg_last_set_value = (rtx *) alloca (nregs * sizeof (rtx)); - reg_last_set_table_tick = (int *) alloca (nregs * sizeof (int)); - reg_last_set_label = (int *) alloca (nregs * sizeof (int)); - reg_last_set_invalid = (char *) alloca (nregs * sizeof (char)); - reg_last_set_mode - = (enum machine_mode *) alloca (nregs * sizeof (enum machine_mode)); - reg_last_set_nonzero_bits - = (unsigned HOST_WIDE_INT *) alloca (nregs * sizeof (HOST_WIDE_INT)); - reg_last_set_sign_bit_copies - = (char *) alloca (nregs * sizeof (char)); - - init_reg_last_arrays (); - - init_recog_no_volatile (); - - /* Compute maximum uid value so uid_cuid can be allocated. */ - - for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) - if (INSN_UID (insn) > i) - i = INSN_UID (insn); - - uid_cuid = (int *) alloca ((i + 1) * sizeof (int)); - max_uid_cuid = i; - - nonzero_bits_mode = mode_for_size (HOST_BITS_PER_WIDE_INT, MODE_INT, 0); - - /* Don't use reg_nonzero_bits when computing it. This can cause problems - when, for example, we have j <<= 1 in a loop. */ - - nonzero_sign_valid = 0; - - /* Compute the mapping from uids to cuids. - Cuids are numbers assigned to insns, like uids, - except that cuids increase monotonically through the code. - - Scan all SETs and see if we can deduce anything about what - bits are known to be zero for some registers and how many copies - of the sign bit are known to exist for those registers. - - Also set any known values so that we can use it while searching - for what bits are known to be set. */ - - label_tick = 1; - - /* We need to initialize it here, because record_dead_and_set_regs may call - get_last_value. */ - subst_prev_insn = NULL_RTX; - - setup_incoming_promotions (); - - for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) - { - uid_cuid[INSN_UID (insn)] = ++i; - subst_low_cuid = i; - subst_insn = insn; - - if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') - { - note_stores (PATTERN (insn), set_nonzero_bits_and_sign_copies); - record_dead_and_set_regs (insn); - -#ifdef AUTO_INC_DEC - for (links = REG_NOTES (insn); links; links = XEXP (links, 1)) - if (REG_NOTE_KIND (links) == REG_INC) - set_nonzero_bits_and_sign_copies (XEXP (links, 0), NULL_RTX); -#endif - } - - if (GET_CODE (insn) == CODE_LABEL) - label_tick++; - } - - nonzero_sign_valid = 1; - - /* Now scan all the insns in forward order. */ - - this_basic_block = -1; - label_tick = 1; - last_call_cuid = 0; - mem_last_set = 0; - init_reg_last_arrays (); - setup_incoming_promotions (); - - for (insn = f; insn; insn = next ? next : NEXT_INSN (insn)) - { - next = 0; - - /* If INSN starts a new basic block, update our basic block number. */ - if (this_basic_block + 1 < n_basic_blocks - && BLOCK_HEAD (this_basic_block + 1) == insn) - this_basic_block++; - - if (GET_CODE (insn) == CODE_LABEL) - label_tick++; - - else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') - { - /* Try this insn with each insn it links back to. */ - - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) - if ((next = try_combine (insn, XEXP (links, 0), NULL_RTX)) != 0) - goto retry; - - /* Try each sequence of three linked insns ending with this one. */ - - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) - for (nextlinks = LOG_LINKS (XEXP (links, 0)); nextlinks; - nextlinks = XEXP (nextlinks, 1)) - if ((next = try_combine (insn, XEXP (links, 0), - XEXP (nextlinks, 0))) != 0) - goto retry; - -#ifdef HAVE_cc0 - /* Try to combine a jump insn that uses CC0 - with a preceding insn that sets CC0, and maybe with its - logical predecessor as well. - This is how we make decrement-and-branch insns. - We need this special code because data flow connections - via CC0 do not get entered in LOG_LINKS. */ - - if (GET_CODE (insn) == JUMP_INSN - && (prev = prev_nonnote_insn (insn)) != 0 - && GET_CODE (prev) == INSN - && sets_cc0_p (PATTERN (prev))) - { - if ((next = try_combine (insn, prev, NULL_RTX)) != 0) - goto retry; - - for (nextlinks = LOG_LINKS (prev); nextlinks; - nextlinks = XEXP (nextlinks, 1)) - if ((next = try_combine (insn, prev, - XEXP (nextlinks, 0))) != 0) - goto retry; - } - - /* Do the same for an insn that explicitly references CC0. */ - if (GET_CODE (insn) == INSN - && (prev = prev_nonnote_insn (insn)) != 0 - && GET_CODE (prev) == INSN - && sets_cc0_p (PATTERN (prev)) - && GET_CODE (PATTERN (insn)) == SET - && reg_mentioned_p (cc0_rtx, SET_SRC (PATTERN (insn)))) - { - if ((next = try_combine (insn, prev, NULL_RTX)) != 0) - goto retry; - - for (nextlinks = LOG_LINKS (prev); nextlinks; - nextlinks = XEXP (nextlinks, 1)) - if ((next = try_combine (insn, prev, - XEXP (nextlinks, 0))) != 0) - goto retry; - } - - /* Finally, see if any of the insns that this insn links to - explicitly references CC0. If so, try this insn, that insn, - and its predecessor if it sets CC0. */ - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) - if (GET_CODE (XEXP (links, 0)) == INSN - && GET_CODE (PATTERN (XEXP (links, 0))) == SET - && reg_mentioned_p (cc0_rtx, SET_SRC (PATTERN (XEXP (links, 0)))) - && (prev = prev_nonnote_insn (XEXP (links, 0))) != 0 - && GET_CODE (prev) == INSN - && sets_cc0_p (PATTERN (prev)) - && (next = try_combine (insn, XEXP (links, 0), prev)) != 0) - goto retry; -#endif - - /* Try combining an insn with two different insns whose results it - uses. */ - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) - for (nextlinks = XEXP (links, 1); nextlinks; - nextlinks = XEXP (nextlinks, 1)) - if ((next = try_combine (insn, XEXP (links, 0), - XEXP (nextlinks, 0))) != 0) - goto retry; - - if (GET_CODE (insn) != NOTE) - record_dead_and_set_regs (insn); - - retry: - ; - } - } - - total_attempts += combine_attempts; - total_merges += combine_merges; - total_extras += combine_extras; - total_successes += combine_successes; - - nonzero_sign_valid = 0; - - /* Make recognizer allow volatile MEMs again. */ - init_recog (); -} - -/* Wipe the reg_last_xxx arrays in preparation for another pass. */ - -static void -init_reg_last_arrays () -{ - int nregs = combine_max_regno; - - bzero ((char *) reg_last_death, nregs * sizeof (rtx)); - bzero ((char *) reg_last_set, nregs * sizeof (rtx)); - bzero ((char *) reg_last_set_value, nregs * sizeof (rtx)); - bzero ((char *) reg_last_set_table_tick, nregs * sizeof (int)); - bzero ((char *) reg_last_set_label, nregs * sizeof (int)); - bzero (reg_last_set_invalid, nregs * sizeof (char)); - bzero ((char *) reg_last_set_mode, nregs * sizeof (enum machine_mode)); - bzero ((char *) reg_last_set_nonzero_bits, nregs * sizeof (HOST_WIDE_INT)); - bzero (reg_last_set_sign_bit_copies, nregs * sizeof (char)); -} - -/* Set up any promoted values for incoming argument registers. */ - -static void -setup_incoming_promotions () -{ -#ifdef PROMOTE_FUNCTION_ARGS - int regno; - rtx reg; - enum machine_mode mode; - int unsignedp; - rtx first = get_insns (); - - for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) - if (FUNCTION_ARG_REGNO_P (regno) - && (reg = promoted_input_arg (regno, &mode, &unsignedp)) != 0) - { - record_value_for_reg - (reg, first, gen_rtx_fmt_e ((unsignedp ? ZERO_EXTEND - : SIGN_EXTEND), - GET_MODE (reg), - gen_rtx_CLOBBER (mode, const0_rtx))); - } -#endif -} - -/* Called via note_stores. If X is a pseudo that is narrower than - HOST_BITS_PER_WIDE_INT and is being set, record what bits are known zero. - - If we are setting only a portion of X and we can't figure out what - portion, assume all bits will be used since we don't know what will - be happening. - - Similarly, set how many bits of X are known to be copies of the sign bit - at all locations in the function. This is the smallest number implied - by any set of X. */ - -static void -set_nonzero_bits_and_sign_copies (x, set) - rtx x; - rtx set; -{ - int num; - - if (GET_CODE (x) == REG - && REGNO (x) >= FIRST_PSEUDO_REGISTER - /* If this register is undefined at the start of the file, we can't - say what its contents were. */ - && ! REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, REGNO (x)) - && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT) - { - if (set == 0 || GET_CODE (set) == CLOBBER) - { - reg_nonzero_bits[REGNO (x)] = GET_MODE_MASK (GET_MODE (x)); - reg_sign_bit_copies[REGNO (x)] = 1; - return; - } - - /* If this is a complex assignment, see if we can convert it into a - simple assignment. */ - set = expand_field_assignment (set); - - /* If this is a simple assignment, or we have a paradoxical SUBREG, - set what we know about X. */ - - if (SET_DEST (set) == x - || (GET_CODE (SET_DEST (set)) == SUBREG - && (GET_MODE_SIZE (GET_MODE (SET_DEST (set))) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (set))))) - && SUBREG_REG (SET_DEST (set)) == x)) - { - rtx src = SET_SRC (set); - -#ifdef SHORT_IMMEDIATES_SIGN_EXTEND - /* If X is narrower than a word and SRC is a non-negative - constant that would appear negative in the mode of X, - sign-extend it for use in reg_nonzero_bits because some - machines (maybe most) will actually do the sign-extension - and this is the conservative approach. - - ??? For 2.5, try to tighten up the MD files in this regard - instead of this kludge. */ - - if (GET_MODE_BITSIZE (GET_MODE (x)) < BITS_PER_WORD - && GET_CODE (src) == CONST_INT - && INTVAL (src) > 0 - && 0 != (INTVAL (src) - & ((HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (GET_MODE (x)) - 1)))) - src = GEN_INT (INTVAL (src) - | ((HOST_WIDE_INT) (-1) - << GET_MODE_BITSIZE (GET_MODE (x)))); -#endif - - reg_nonzero_bits[REGNO (x)] - |= nonzero_bits (src, nonzero_bits_mode); - num = num_sign_bit_copies (SET_SRC (set), GET_MODE (x)); - if (reg_sign_bit_copies[REGNO (x)] == 0 - || reg_sign_bit_copies[REGNO (x)] > num) - reg_sign_bit_copies[REGNO (x)] = num; - } - else - { - reg_nonzero_bits[REGNO (x)] = GET_MODE_MASK (GET_MODE (x)); - reg_sign_bit_copies[REGNO (x)] = 1; - } - } -} - -/* See if INSN can be combined into I3. PRED and SUCC are optionally - insns that were previously combined into I3 or that will be combined - into the merger of INSN and I3. - - Return 0 if the combination is not allowed for any reason. - - If the combination is allowed, *PDEST will be set to the single - destination of INSN and *PSRC to the single source, and this function - will return 1. */ - -static int -can_combine_p (insn, i3, pred, succ, pdest, psrc) - rtx insn; - rtx i3; - rtx pred ATTRIBUTE_UNUSED; - rtx succ; - rtx *pdest, *psrc; -{ - int i; - rtx set = 0, src, dest; - rtx p; -#ifdef AUTO_INC_DEC - rtx link; -#endif - int all_adjacent = (succ ? (next_active_insn (insn) == succ - && next_active_insn (succ) == i3) - : next_active_insn (insn) == i3); - - /* Can combine only if previous insn is a SET of a REG, a SUBREG or CC0. - or a PARALLEL consisting of such a SET and CLOBBERs. - - If INSN has CLOBBER parallel parts, ignore them for our processing. - By definition, these happen during the execution of the insn. When it - is merged with another insn, all bets are off. If they are, in fact, - needed and aren't also supplied in I3, they may be added by - recog_for_combine. Otherwise, it won't match. - - We can also ignore a SET whose SET_DEST is mentioned in a REG_UNUSED - note. - - Get the source and destination of INSN. If more than one, can't - combine. */ - - if (GET_CODE (PATTERN (insn)) == SET) - set = PATTERN (insn); - else if (GET_CODE (PATTERN (insn)) == PARALLEL - && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET) - { - for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++) - { - rtx elt = XVECEXP (PATTERN (insn), 0, i); - - switch (GET_CODE (elt)) - { - /* This is important to combine floating point insns - for the SH4 port. */ - case USE: - /* Combining an isolated USE doesn't make sense. - We depend here on combinable_i3_pat to reject them. */ - /* The code below this loop only verifies that the inputs of - the SET in INSN do not change. We call reg_set_between_p - to verify that the REG in the USE does not change betweeen - I3 and INSN. - If the USE in INSN was for a pseudo register, the matching - insn pattern will likely match any register; combining this - with any other USE would only be safe if we knew that the - used registers have identical values, or if there was - something to tell them apart, e.g. different modes. For - now, we forgo such compilcated tests and simply disallow - combining of USES of pseudo registers with any other USE. */ - if (GET_CODE (XEXP (elt, 0)) == REG - && GET_CODE (PATTERN (i3)) == PARALLEL) - { - rtx i3pat = PATTERN (i3); - int i = XVECLEN (i3pat, 0) - 1; - int regno = REGNO (XEXP (elt, 0)); - do - { - rtx i3elt = XVECEXP (i3pat, 0, i); - if (GET_CODE (i3elt) == USE - && GET_CODE (XEXP (i3elt, 0)) == REG - && (REGNO (XEXP (i3elt, 0)) == regno - ? reg_set_between_p (XEXP (elt, 0), - PREV_INSN (insn), i3) - : regno >= FIRST_PSEUDO_REGISTER)) - return 0; - } - while (--i >= 0); - } - break; - - /* We can ignore CLOBBERs. */ - case CLOBBER: - break; - - case SET: - /* Ignore SETs whose result isn't used but not those that - have side-effects. */ - if (find_reg_note (insn, REG_UNUSED, SET_DEST (elt)) - && ! side_effects_p (elt)) - break; - - /* If we have already found a SET, this is a second one and - so we cannot combine with this insn. */ - if (set) - return 0; - - set = elt; - break; - - default: - /* Anything else means we can't combine. */ - return 0; - } - } - - if (set == 0 - /* If SET_SRC is an ASM_OPERANDS we can't throw away these CLOBBERs, - so don't do anything with it. */ - || GET_CODE (SET_SRC (set)) == ASM_OPERANDS) - return 0; - } - else - return 0; - - if (set == 0) - return 0; - - set = expand_field_assignment (set); - src = SET_SRC (set), dest = SET_DEST (set); - - /* Don't eliminate a store in the stack pointer. */ - if (dest == stack_pointer_rtx - /* If we couldn't eliminate a field assignment, we can't combine. */ - || GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == STRICT_LOW_PART - /* Don't combine with an insn that sets a register to itself if it has - a REG_EQUAL note. This may be part of a REG_NO_CONFLICT sequence. */ - || (rtx_equal_p (src, dest) && find_reg_note (insn, REG_EQUAL, NULL_RTX)) - /* Can't merge a function call. */ - || GET_CODE (src) == CALL - /* Don't eliminate a function call argument. */ - || (GET_CODE (i3) == CALL_INSN - && (find_reg_fusage (i3, USE, dest) - || (GET_CODE (dest) == REG - && REGNO (dest) < FIRST_PSEUDO_REGISTER - && global_regs[REGNO (dest)]))) - /* Don't substitute into an incremented register. */ - || FIND_REG_INC_NOTE (i3, dest) - || (succ && FIND_REG_INC_NOTE (succ, dest)) -#if 0 - /* Don't combine the end of a libcall into anything. */ - /* ??? This gives worse code, and appears to be unnecessary, since no - pass after flow uses REG_LIBCALL/REG_RETVAL notes. Local-alloc does - use REG_RETVAL notes for noconflict blocks, but other code here - makes sure that those insns don't disappear. */ - || find_reg_note (insn, REG_RETVAL, NULL_RTX) -#endif - /* Make sure that DEST is not used after SUCC but before I3. */ - || (succ && ! all_adjacent - && reg_used_between_p (dest, succ, i3)) - /* Make sure that the value that is to be substituted for the register - does not use any registers whose values alter in between. However, - If the insns are adjacent, a use can't cross a set even though we - think it might (this can happen for a sequence of insns each setting - the same destination; reg_last_set of that register might point to - a NOTE). If INSN has a REG_EQUIV note, the register is always - equivalent to the memory so the substitution is valid even if there - are intervening stores. Also, don't move a volatile asm or - UNSPEC_VOLATILE across any other insns. */ - || (! all_adjacent - && (((GET_CODE (src) != MEM - || ! find_reg_note (insn, REG_EQUIV, src)) - && use_crosses_set_p (src, INSN_CUID (insn))) - || (GET_CODE (src) == ASM_OPERANDS && MEM_VOLATILE_P (src)) - || GET_CODE (src) == UNSPEC_VOLATILE)) - /* If there is a REG_NO_CONFLICT note for DEST in I3 or SUCC, we get - better register allocation by not doing the combine. */ - || find_reg_note (i3, REG_NO_CONFLICT, dest) - || (succ && find_reg_note (succ, REG_NO_CONFLICT, dest)) - /* Don't combine across a CALL_INSN, because that would possibly - change whether the life span of some REGs crosses calls or not, - and it is a pain to update that information. - Exception: if source is a constant, moving it later can't hurt. - Accept that special case, because it helps -fforce-addr a lot. */ - || (INSN_CUID (insn) < last_call_cuid && ! CONSTANT_P (src))) - return 0; - - /* DEST must either be a REG or CC0. */ - if (GET_CODE (dest) == REG) - { - /* If register alignment is being enforced for multi-word items in all - cases except for parameters, it is possible to have a register copy - insn referencing a hard register that is not allowed to contain the - mode being copied and which would not be valid as an operand of most - insns. Eliminate this problem by not combining with such an insn. - - Also, on some machines we don't want to extend the life of a hard - register. - - This is the same test done in can_combine except that we don't test - if SRC is a CALL operation to permit a hard register with - SMALL_REGISTER_CLASSES, and that we have to take all_adjacent - into account. */ - - if (GET_CODE (src) == REG - && ((REGNO (dest) < FIRST_PSEUDO_REGISTER - && ! HARD_REGNO_MODE_OK (REGNO (dest), GET_MODE (dest))) - /* Don't extend the life of a hard register unless it is - user variable (if we have few registers) or it can't - fit into the desired register (meaning something special - is going on). - Also avoid substituting a return register into I3, because - reload can't handle a conflict with constraints of other - inputs. */ - || (REGNO (src) < FIRST_PSEUDO_REGISTER - && (! HARD_REGNO_MODE_OK (REGNO (src), GET_MODE (src)) - || (SMALL_REGISTER_CLASSES - && ((! all_adjacent && ! REG_USERVAR_P (src)) - || (FUNCTION_VALUE_REGNO_P (REGNO (src)) - && ! REG_USERVAR_P (src)))))))) - return 0; - } - else if (GET_CODE (dest) != CC0) - return 0; - - /* Don't substitute for a register intended as a clobberable operand. - Similarly, don't substitute an expression containing a register that - will be clobbered in I3. */ - if (GET_CODE (PATTERN (i3)) == PARALLEL) - for (i = XVECLEN (PATTERN (i3), 0) - 1; i >= 0; i--) - if (GET_CODE (XVECEXP (PATTERN (i3), 0, i)) == CLOBBER - && (reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (i3), 0, i), 0), - src) - || rtx_equal_p (XEXP (XVECEXP (PATTERN (i3), 0, i), 0), dest))) - return 0; - - /* If INSN contains anything volatile, or is an `asm' (whether volatile - or not), reject, unless nothing volatile comes between it and I3 */ - - if (GET_CODE (src) == ASM_OPERANDS || volatile_refs_p (src)) - { - /* Make sure succ doesn't contain a volatile reference. */ - if (succ != 0 && volatile_refs_p (PATTERN (succ))) - return 0; - - for (p = NEXT_INSN (insn); p != i3; p = NEXT_INSN (p)) - if (GET_RTX_CLASS (GET_CODE (p)) == 'i' - && p != succ && volatile_refs_p (PATTERN (p))) - return 0; - } - - /* If INSN is an asm, and DEST is a hard register, reject, since it has - to be an explicit register variable, and was chosen for a reason. */ - - if (GET_CODE (src) == ASM_OPERANDS - && GET_CODE (dest) == REG && REGNO (dest) < FIRST_PSEUDO_REGISTER) - return 0; - - /* If there are any volatile insns between INSN and I3, reject, because - they might affect machine state. */ - - for (p = NEXT_INSN (insn); p != i3; p = NEXT_INSN (p)) - if (GET_RTX_CLASS (GET_CODE (p)) == 'i' - && p != succ && volatile_insn_p (PATTERN (p))) - return 0; - - /* If INSN or I2 contains an autoincrement or autodecrement, - make sure that register is not used between there and I3, - and not already used in I3 either. - Also insist that I3 not be a jump; if it were one - and the incremented register were spilled, we would lose. */ - -#ifdef AUTO_INC_DEC - for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) - if (REG_NOTE_KIND (link) == REG_INC - && (GET_CODE (i3) == JUMP_INSN - || reg_used_between_p (XEXP (link, 0), insn, i3) - || reg_overlap_mentioned_p (XEXP (link, 0), PATTERN (i3)))) - return 0; -#endif - -#ifdef HAVE_cc0 - /* Don't combine an insn that follows a CC0-setting insn. - An insn that uses CC0 must not be separated from the one that sets it. - We do, however, allow I2 to follow a CC0-setting insn if that insn - is passed as I1; in that case it will be deleted also. - We also allow combining in this case if all the insns are adjacent - because that would leave the two CC0 insns adjacent as well. - It would be more logical to test whether CC0 occurs inside I1 or I2, - but that would be much slower, and this ought to be equivalent. */ - - p = prev_nonnote_insn (insn); - if (p && p != pred && GET_CODE (p) == INSN && sets_cc0_p (PATTERN (p)) - && ! all_adjacent) - return 0; -#endif - - /* If we get here, we have passed all the tests and the combination is - to be allowed. */ - - *pdest = dest; - *psrc = src; - - return 1; -} - -/* Check if PAT is an insn - or a part of it - used to set up an - argument for a function in a hard register. */ - -static int -sets_function_arg_p (pat) - rtx pat; -{ - int i; - rtx inner_dest; - - switch (GET_CODE (pat)) - { - case INSN: - return sets_function_arg_p (PATTERN (pat)); - - case PARALLEL: - for (i = XVECLEN (pat, 0); --i >= 0;) - if (sets_function_arg_p (XVECEXP (pat, 0, i))) - return 1; - - break; - - case SET: - inner_dest = SET_DEST (pat); - while (GET_CODE (inner_dest) == STRICT_LOW_PART - || GET_CODE (inner_dest) == SUBREG - || GET_CODE (inner_dest) == ZERO_EXTRACT) - inner_dest = XEXP (inner_dest, 0); - - return (GET_CODE (inner_dest) == REG - && REGNO (inner_dest) < FIRST_PSEUDO_REGISTER - && FUNCTION_ARG_REGNO_P (REGNO (inner_dest))); - - default: - break; - } - - return 0; -} - -/* LOC is the location within I3 that contains its pattern or the component - of a PARALLEL of the pattern. We validate that it is valid for combining. - - One problem is if I3 modifies its output, as opposed to replacing it - entirely, we can't allow the output to contain I2DEST or I1DEST as doing - so would produce an insn that is not equivalent to the original insns. - - Consider: - - (set (reg:DI 101) (reg:DI 100)) - (set (subreg:SI (reg:DI 101) 0) <foo>) - - This is NOT equivalent to: - - (parallel [(set (subreg:SI (reg:DI 100) 0) <foo>) - (set (reg:DI 101) (reg:DI 100))]) - - Not only does this modify 100 (in which case it might still be valid - if 100 were dead in I2), it sets 101 to the ORIGINAL value of 100. - - We can also run into a problem if I2 sets a register that I1 - uses and I1 gets directly substituted into I3 (not via I2). In that - case, we would be getting the wrong value of I2DEST into I3, so we - must reject the combination. This case occurs when I2 and I1 both - feed into I3, rather than when I1 feeds into I2, which feeds into I3. - If I1_NOT_IN_SRC is non-zero, it means that finding I1 in the source - of a SET must prevent combination from occurring. - - On machines where SMALL_REGISTER_CLASSES is non-zero, we don't combine - if the destination of a SET is a hard register that isn't a user - variable. - - Before doing the above check, we first try to expand a field assignment - into a set of logical operations. - - If PI3_DEST_KILLED is non-zero, it is a pointer to a location in which - we place a register that is both set and used within I3. If more than one - such register is detected, we fail. - - Return 1 if the combination is valid, zero otherwise. */ - -static int -combinable_i3pat (i3, loc, i2dest, i1dest, i1_not_in_src, pi3dest_killed) - rtx i3; - rtx *loc; - rtx i2dest; - rtx i1dest; - int i1_not_in_src; - rtx *pi3dest_killed; -{ - rtx x = *loc; - - if (GET_CODE (x) == SET) - { - rtx set = expand_field_assignment (x); - rtx dest = SET_DEST (set); - rtx src = SET_SRC (set); - rtx inner_dest = dest; - -#if 0 - rtx inner_src = src; -#endif - - SUBST (*loc, set); - - while (GET_CODE (inner_dest) == STRICT_LOW_PART - || GET_CODE (inner_dest) == SUBREG - || GET_CODE (inner_dest) == ZERO_EXTRACT) - inner_dest = XEXP (inner_dest, 0); - - /* We probably don't need this any more now that LIMIT_RELOAD_CLASS - was added. */ -#if 0 - while (GET_CODE (inner_src) == STRICT_LOW_PART - || GET_CODE (inner_src) == SUBREG - || GET_CODE (inner_src) == ZERO_EXTRACT) - inner_src = XEXP (inner_src, 0); - - /* If it is better that two different modes keep two different pseudos, - avoid combining them. This avoids producing the following pattern - on a 386: - (set (subreg:SI (reg/v:QI 21) 0) - (lshiftrt:SI (reg/v:SI 20) - (const_int 24))) - If that were made, reload could not handle the pair of - reg 20/21, since it would try to get any GENERAL_REGS - but some of them don't handle QImode. */ - - if (rtx_equal_p (inner_src, i2dest) - && GET_CODE (inner_dest) == REG - && ! MODES_TIEABLE_P (GET_MODE (i2dest), GET_MODE (inner_dest))) - return 0; -#endif - - /* Check for the case where I3 modifies its output, as - discussed above. */ - if ((inner_dest != dest - && (reg_overlap_mentioned_p (i2dest, inner_dest) - || (i1dest && reg_overlap_mentioned_p (i1dest, inner_dest)))) - - /* This is the same test done in can_combine_p except that we - allow a hard register with SMALL_REGISTER_CLASSES if SRC is a - CALL operation. Moreover, we can't test all_adjacent; we don't - have to, since this instruction will stay in place, thus we are - not considering increasing the lifetime of INNER_DEST. - - Also, if this insn sets a function argument, combining it with - something that might need a spill could clobber a previous - function argument; the all_adjacent test in can_combine_p also - checks this; here, we do a more specific test for this case. */ - - || (GET_CODE (inner_dest) == REG - && REGNO (inner_dest) < FIRST_PSEUDO_REGISTER - && (! HARD_REGNO_MODE_OK (REGNO (inner_dest), - GET_MODE (inner_dest)) - || (SMALL_REGISTER_CLASSES && GET_CODE (src) != CALL - && ! REG_USERVAR_P (inner_dest) - && (FUNCTION_VALUE_REGNO_P (REGNO (inner_dest)) - || (FUNCTION_ARG_REGNO_P (REGNO (inner_dest)) - && i3 != 0 - && sets_function_arg_p (prev_nonnote_insn (i3))))))) - || (i1_not_in_src && reg_overlap_mentioned_p (i1dest, src))) - return 0; - - /* If DEST is used in I3, it is being killed in this insn, - so record that for later. - Never add REG_DEAD notes for the FRAME_POINTER_REGNUM or the - STACK_POINTER_REGNUM, since these are always considered to be - live. Similarly for ARG_POINTER_REGNUM if it is fixed. */ - if (pi3dest_killed && GET_CODE (dest) == REG - && reg_referenced_p (dest, PATTERN (i3)) - && REGNO (dest) != FRAME_POINTER_REGNUM -#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM - && REGNO (dest) != HARD_FRAME_POINTER_REGNUM -#endif -#if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM - && (REGNO (dest) != ARG_POINTER_REGNUM - || ! fixed_regs [REGNO (dest)]) -#endif - && REGNO (dest) != STACK_POINTER_REGNUM) - { - if (*pi3dest_killed) - return 0; - - *pi3dest_killed = dest; - } - } - - else if (GET_CODE (x) == PARALLEL) - { - int i; - - for (i = 0; i < XVECLEN (x, 0); i++) - if (! combinable_i3pat (i3, &XVECEXP (x, 0, i), i2dest, i1dest, - i1_not_in_src, pi3dest_killed)) - return 0; - } - - return 1; -} - -/* Try to combine the insns I1 and I2 into I3. - Here I1 and I2 appear earlier than I3. - I1 can be zero; then we combine just I2 into I3. - - It we are combining three insns and the resulting insn is not recognized, - try splitting it into two insns. If that happens, I2 and I3 are retained - and I1 is pseudo-deleted by turning it into a NOTE. Otherwise, I1 and I2 - are pseudo-deleted. - - Return 0 if the combination does not work. Then nothing is changed. - If we did the combination, return the insn at which combine should - resume scanning. */ - -static rtx -try_combine (i3, i2, i1) - register rtx i3, i2, i1; -{ - /* New patterns for I3 and I3, respectively. */ - rtx newpat, newi2pat = 0; - /* Indicates need to preserve SET in I1 or I2 in I3 if it is not dead. */ - int added_sets_1, added_sets_2; - /* Total number of SETs to put into I3. */ - int total_sets; - /* Nonzero is I2's body now appears in I3. */ - int i2_is_used; - /* INSN_CODEs for new I3, new I2, and user of condition code. */ - int insn_code_number, i2_code_number, other_code_number; - /* Contains I3 if the destination of I3 is used in its source, which means - that the old life of I3 is being killed. If that usage is placed into - I2 and not in I3, a REG_DEAD note must be made. */ - rtx i3dest_killed = 0; - /* SET_DEST and SET_SRC of I2 and I1. */ - rtx i2dest, i2src, i1dest = 0, i1src = 0; - /* PATTERN (I2), or a copy of it in certain cases. */ - rtx i2pat; - /* Indicates if I2DEST or I1DEST is in I2SRC or I1_SRC. */ - int i2dest_in_i2src = 0, i1dest_in_i1src = 0, i2dest_in_i1src = 0; - int i1_feeds_i3 = 0; - /* Notes that must be added to REG_NOTES in I3 and I2. */ - rtx new_i3_notes, new_i2_notes; - /* Notes that we substituted I3 into I2 instead of the normal case. */ - int i3_subst_into_i2 = 0; - /* Notes that I1, I2 or I3 is a MULT operation. */ - int have_mult = 0; - - int maxreg; - rtx temp; - register rtx link; - int i; - - /* If any of I1, I2, and I3 isn't really an insn, we can't do anything. - This can occur when flow deletes an insn that it has merged into an - auto-increment address. We also can't do anything if I3 has a - REG_LIBCALL note since we don't want to disrupt the contiguity of a - libcall. */ - - if (GET_RTX_CLASS (GET_CODE (i3)) != 'i' - || GET_RTX_CLASS (GET_CODE (i2)) != 'i' - || (i1 && GET_RTX_CLASS (GET_CODE (i1)) != 'i') -#if 0 - /* ??? This gives worse code, and appears to be unnecessary, since no - pass after flow uses REG_LIBCALL/REG_RETVAL notes. */ - || find_reg_note (i3, REG_LIBCALL, NULL_RTX) -#endif -) - return 0; - - combine_attempts++; - - undobuf.undos = undobuf.previous_undos = 0; - undobuf.other_insn = 0; - - /* Save the current high-water-mark so we can free storage if we didn't - accept this combination. */ - undobuf.storage = (char *) oballoc (0); - - /* Reset the hard register usage information. */ - CLEAR_HARD_REG_SET (newpat_used_regs); - - /* If I1 and I2 both feed I3, they can be in any order. To simplify the - code below, set I1 to be the earlier of the two insns. */ - if (i1 && INSN_CUID (i1) > INSN_CUID (i2)) - temp = i1, i1 = i2, i2 = temp; - - added_links_insn = 0; - - /* First check for one important special-case that the code below will - not handle. Namely, the case where I1 is zero, I2 has multiple sets, - and I3 is a SET whose SET_SRC is a SET_DEST in I2. In that case, - we may be able to replace that destination with the destination of I3. - This occurs in the common code where we compute both a quotient and - remainder into a structure, in which case we want to do the computation - directly into the structure to avoid register-register copies. - - We make very conservative checks below and only try to handle the - most common cases of this. For example, we only handle the case - where I2 and I3 are adjacent to avoid making difficult register - usage tests. */ - - if (i1 == 0 && GET_CODE (i3) == INSN && GET_CODE (PATTERN (i3)) == SET - && GET_CODE (SET_SRC (PATTERN (i3))) == REG - && REGNO (SET_SRC (PATTERN (i3))) >= FIRST_PSEUDO_REGISTER - && (! SMALL_REGISTER_CLASSES - || (GET_CODE (SET_DEST (PATTERN (i3))) != REG - || REGNO (SET_DEST (PATTERN (i3))) >= FIRST_PSEUDO_REGISTER - || REG_USERVAR_P (SET_DEST (PATTERN (i3))))) - && find_reg_note (i3, REG_DEAD, SET_SRC (PATTERN (i3))) - && GET_CODE (PATTERN (i2)) == PARALLEL - && ! side_effects_p (SET_DEST (PATTERN (i3))) - /* If the dest of I3 is a ZERO_EXTRACT or STRICT_LOW_PART, the code - below would need to check what is inside (and reg_overlap_mentioned_p - doesn't support those codes anyway). Don't allow those destinations; - the resulting insn isn't likely to be recognized anyway. */ - && GET_CODE (SET_DEST (PATTERN (i3))) != ZERO_EXTRACT - && GET_CODE (SET_DEST (PATTERN (i3))) != STRICT_LOW_PART - && ! reg_overlap_mentioned_p (SET_SRC (PATTERN (i3)), - SET_DEST (PATTERN (i3))) - && next_real_insn (i2) == i3) - { - rtx p2 = PATTERN (i2); - - /* Make sure that the destination of I3, - which we are going to substitute into one output of I2, - is not used within another output of I2. We must avoid making this: - (parallel [(set (mem (reg 69)) ...) - (set (reg 69) ...)]) - which is not well-defined as to order of actions. - (Besides, reload can't handle output reloads for this.) - - The problem can also happen if the dest of I3 is a memory ref, - if another dest in I2 is an indirect memory ref. */ - for (i = 0; i < XVECLEN (p2, 0); i++) - if ((GET_CODE (XVECEXP (p2, 0, i)) == SET - || GET_CODE (XVECEXP (p2, 0, i)) == CLOBBER) - && reg_overlap_mentioned_p (SET_DEST (PATTERN (i3)), - SET_DEST (XVECEXP (p2, 0, i)))) - break; - - if (i == XVECLEN (p2, 0)) - for (i = 0; i < XVECLEN (p2, 0); i++) - if (SET_DEST (XVECEXP (p2, 0, i)) == SET_SRC (PATTERN (i3))) - { - combine_merges++; - - subst_insn = i3; - subst_low_cuid = INSN_CUID (i2); - - added_sets_2 = added_sets_1 = 0; - i2dest = SET_SRC (PATTERN (i3)); - - /* Replace the dest in I2 with our dest and make the resulting - insn the new pattern for I3. Then skip to where we - validate the pattern. Everything was set up above. */ - SUBST (SET_DEST (XVECEXP (p2, 0, i)), - SET_DEST (PATTERN (i3))); - - newpat = p2; - i3_subst_into_i2 = 1; - goto validate_replacement; - } - } - -#ifndef HAVE_cc0 - /* If we have no I1 and I2 looks like: - (parallel [(set (reg:CC X) (compare:CC OP (const_int 0))) - (set Y OP)]) - make up a dummy I1 that is - (set Y OP) - and change I2 to be - (set (reg:CC X) (compare:CC Y (const_int 0))) - - (We can ignore any trailing CLOBBERs.) - - This undoes a previous combination and allows us to match a branch-and- - decrement insn. */ - - if (i1 == 0 && GET_CODE (PATTERN (i2)) == PARALLEL - && XVECLEN (PATTERN (i2), 0) >= 2 - && GET_CODE (XVECEXP (PATTERN (i2), 0, 0)) == SET - && (GET_MODE_CLASS (GET_MODE (SET_DEST (XVECEXP (PATTERN (i2), 0, 0)))) - == MODE_CC) - && GET_CODE (SET_SRC (XVECEXP (PATTERN (i2), 0, 0))) == COMPARE - && XEXP (SET_SRC (XVECEXP (PATTERN (i2), 0, 0)), 1) == const0_rtx - && GET_CODE (XVECEXP (PATTERN (i2), 0, 1)) == SET - && GET_CODE (SET_DEST (XVECEXP (PATTERN (i2), 0, 1))) == REG - && rtx_equal_p (XEXP (SET_SRC (XVECEXP (PATTERN (i2), 0, 0)), 0), - SET_SRC (XVECEXP (PATTERN (i2), 0, 1)))) - { - for (i = XVECLEN (PATTERN (i2), 0) - 1; i >= 2; i--) - if (GET_CODE (XVECEXP (PATTERN (i2), 0, i)) != CLOBBER) - break; - - if (i == 1) - { - /* We make I1 with the same INSN_UID as I2. This gives it - the same INSN_CUID for value tracking. Our fake I1 will - never appear in the insn stream so giving it the same INSN_UID - as I2 will not cause a problem. */ - - subst_prev_insn = i1 - = gen_rtx_INSN (VOIDmode, INSN_UID (i2), NULL_RTX, i2, - XVECEXP (PATTERN (i2), 0, 1), -1, NULL_RTX, - NULL_RTX); - - SUBST (PATTERN (i2), XVECEXP (PATTERN (i2), 0, 0)); - SUBST (XEXP (SET_SRC (PATTERN (i2)), 0), - SET_DEST (PATTERN (i1))); - } - } -#endif - - /* Verify that I2 and I1 are valid for combining. */ - if (! can_combine_p (i2, i3, i1, NULL_RTX, &i2dest, &i2src) - || (i1 && ! can_combine_p (i1, i3, NULL_RTX, i2, &i1dest, &i1src))) - { - undo_all (); - return 0; - } - - /* Record whether I2DEST is used in I2SRC and similarly for the other - cases. Knowing this will help in register status updating below. */ - i2dest_in_i2src = reg_overlap_mentioned_p (i2dest, i2src); - i1dest_in_i1src = i1 && reg_overlap_mentioned_p (i1dest, i1src); - i2dest_in_i1src = i1 && reg_overlap_mentioned_p (i2dest, i1src); - - /* See if I1 directly feeds into I3. It does if I1DEST is not used - in I2SRC. */ - i1_feeds_i3 = i1 && ! reg_overlap_mentioned_p (i1dest, i2src); - - /* Ensure that I3's pattern can be the destination of combines. */ - if (! combinable_i3pat (i3, &PATTERN (i3), i2dest, i1dest, - i1 && i2dest_in_i1src && i1_feeds_i3, - &i3dest_killed)) - { - undo_all (); - return 0; - } - - /* See if any of the insns is a MULT operation. Unless one is, we will - reject a combination that is, since it must be slower. Be conservative - here. */ - if (GET_CODE (i2src) == MULT - || (i1 != 0 && GET_CODE (i1src) == MULT) - || (GET_CODE (PATTERN (i3)) == SET - && GET_CODE (SET_SRC (PATTERN (i3))) == MULT)) - have_mult = 1; - - /* If I3 has an inc, then give up if I1 or I2 uses the reg that is inc'd. - We used to do this EXCEPT in one case: I3 has a post-inc in an - output operand. However, that exception can give rise to insns like - mov r3,(r3)+ - which is a famous insn on the PDP-11 where the value of r3 used as the - source was model-dependent. Avoid this sort of thing. */ - -#if 0 - if (!(GET_CODE (PATTERN (i3)) == SET - && GET_CODE (SET_SRC (PATTERN (i3))) == REG - && GET_CODE (SET_DEST (PATTERN (i3))) == MEM - && (GET_CODE (XEXP (SET_DEST (PATTERN (i3)), 0)) == POST_INC - || GET_CODE (XEXP (SET_DEST (PATTERN (i3)), 0)) == POST_DEC))) - /* It's not the exception. */ -#endif -#ifdef AUTO_INC_DEC - for (link = REG_NOTES (i3); link; link = XEXP (link, 1)) - if (REG_NOTE_KIND (link) == REG_INC - && (reg_overlap_mentioned_p (XEXP (link, 0), PATTERN (i2)) - || (i1 != 0 - && reg_overlap_mentioned_p (XEXP (link, 0), PATTERN (i1))))) - { - undo_all (); - return 0; - } -#endif - - /* See if the SETs in I1 or I2 need to be kept around in the merged - instruction: whenever the value set there is still needed past I3. - For the SETs in I2, this is easy: we see if I2DEST dies or is set in I3. - - For the SET in I1, we have two cases: If I1 and I2 independently - feed into I3, the set in I1 needs to be kept around if I1DEST dies - or is set in I3. Otherwise (if I1 feeds I2 which feeds I3), the set - in I1 needs to be kept around unless I1DEST dies or is set in either - I2 or I3. We can distinguish these cases by seeing if I2SRC mentions - I1DEST. If so, we know I1 feeds into I2. */ - - added_sets_2 = ! dead_or_set_p (i3, i2dest); - - added_sets_1 - = i1 && ! (i1_feeds_i3 ? dead_or_set_p (i3, i1dest) - : (dead_or_set_p (i3, i1dest) || dead_or_set_p (i2, i1dest))); - - /* If the set in I2 needs to be kept around, we must make a copy of - PATTERN (I2), so that when we substitute I1SRC for I1DEST in - PATTERN (I2), we are only substituting for the original I1DEST, not into - an already-substituted copy. This also prevents making self-referential - rtx. If I2 is a PARALLEL, we just need the piece that assigns I2SRC to - I2DEST. */ - - i2pat = (GET_CODE (PATTERN (i2)) == PARALLEL - ? gen_rtx_SET (VOIDmode, i2dest, i2src) - : PATTERN (i2)); - - if (added_sets_2) - i2pat = copy_rtx (i2pat); - - combine_merges++; - - /* Substitute in the latest insn for the regs set by the earlier ones. */ - - maxreg = max_reg_num (); - - subst_insn = i3; - - /* It is possible that the source of I2 or I1 may be performing an - unneeded operation, such as a ZERO_EXTEND of something that is known - to have the high part zero. Handle that case by letting subst look at - the innermost one of them. - - Another way to do this would be to have a function that tries to - simplify a single insn instead of merging two or more insns. We don't - do this because of the potential of infinite loops and because - of the potential extra memory required. However, doing it the way - we are is a bit of a kludge and doesn't catch all cases. - - But only do this if -fexpensive-optimizations since it slows things down - and doesn't usually win. */ - - if (flag_expensive_optimizations) - { - /* Pass pc_rtx so no substitutions are done, just simplifications. - The cases that we are interested in here do not involve the few - cases were is_replaced is checked. */ - if (i1) - { - subst_low_cuid = INSN_CUID (i1); - i1src = subst (i1src, pc_rtx, pc_rtx, 0, 0); - } - else - { - subst_low_cuid = INSN_CUID (i2); - i2src = subst (i2src, pc_rtx, pc_rtx, 0, 0); - } - - undobuf.previous_undos = undobuf.undos; - } - -#ifndef HAVE_cc0 - /* Many machines that don't use CC0 have insns that can both perform an - arithmetic operation and set the condition code. These operations will - be represented as a PARALLEL with the first element of the vector - being a COMPARE of an arithmetic operation with the constant zero. - The second element of the vector will set some pseudo to the result - of the same arithmetic operation. If we simplify the COMPARE, we won't - match such a pattern and so will generate an extra insn. Here we test - for this case, where both the comparison and the operation result are - needed, and make the PARALLEL by just replacing I2DEST in I3SRC with - I2SRC. Later we will make the PARALLEL that contains I2. */ - - if (i1 == 0 && added_sets_2 && GET_CODE (PATTERN (i3)) == SET - && GET_CODE (SET_SRC (PATTERN (i3))) == COMPARE - && XEXP (SET_SRC (PATTERN (i3)), 1) == const0_rtx - && rtx_equal_p (XEXP (SET_SRC (PATTERN (i3)), 0), i2dest)) - { -#ifdef EXTRA_CC_MODES - rtx *cc_use; - enum machine_mode compare_mode; -#endif - - newpat = PATTERN (i3); - SUBST (XEXP (SET_SRC (newpat), 0), i2src); - - i2_is_used = 1; - -#ifdef EXTRA_CC_MODES - /* See if a COMPARE with the operand we substituted in should be done - with the mode that is currently being used. If not, do the same - processing we do in `subst' for a SET; namely, if the destination - is used only once, try to replace it with a register of the proper - mode and also replace the COMPARE. */ - if (undobuf.other_insn == 0 - && (cc_use = find_single_use (SET_DEST (newpat), i3, - &undobuf.other_insn)) - && ((compare_mode = SELECT_CC_MODE (GET_CODE (*cc_use), - i2src, const0_rtx)) - != GET_MODE (SET_DEST (newpat)))) - { - int regno = REGNO (SET_DEST (newpat)); - rtx new_dest = gen_rtx_REG (compare_mode, regno); - - if (regno < FIRST_PSEUDO_REGISTER - || (REG_N_SETS (regno) == 1 && ! added_sets_2 - && ! REG_USERVAR_P (SET_DEST (newpat)))) - { - if (regno >= FIRST_PSEUDO_REGISTER) - SUBST (regno_reg_rtx[regno], new_dest); - - SUBST (SET_DEST (newpat), new_dest); - SUBST (XEXP (*cc_use, 0), new_dest); - SUBST (SET_SRC (newpat), - gen_rtx_combine (COMPARE, compare_mode, - i2src, const0_rtx)); - } - else - undobuf.other_insn = 0; - } -#endif - } - else -#endif - { - n_occurrences = 0; /* `subst' counts here */ - - /* If I1 feeds into I2 (not into I3) and I1DEST is in I1SRC, we - need to make a unique copy of I2SRC each time we substitute it - to avoid self-referential rtl. */ - - subst_low_cuid = INSN_CUID (i2); - newpat = subst (PATTERN (i3), i2dest, i2src, 0, - ! i1_feeds_i3 && i1dest_in_i1src); - undobuf.previous_undos = undobuf.undos; - - /* Record whether i2's body now appears within i3's body. */ - i2_is_used = n_occurrences; - } - - /* If we already got a failure, don't try to do more. Otherwise, - try to substitute in I1 if we have it. */ - - if (i1 && GET_CODE (newpat) != CLOBBER) - { - /* Before we can do this substitution, we must redo the test done - above (see detailed comments there) that ensures that I1DEST - isn't mentioned in any SETs in NEWPAT that are field assignments. */ - - if (! combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX, - 0, NULL_PTR)) - { - undo_all (); - return 0; - } - - n_occurrences = 0; - subst_low_cuid = INSN_CUID (i1); - newpat = subst (newpat, i1dest, i1src, 0, 0); - undobuf.previous_undos = undobuf.undos; - } - - /* Fail if an autoincrement side-effect has been duplicated. Be careful - to count all the ways that I2SRC and I1SRC can be used. */ - if ((FIND_REG_INC_NOTE (i2, NULL_RTX) != 0 - && i2_is_used + added_sets_2 > 1) - || (i1 != 0 && FIND_REG_INC_NOTE (i1, NULL_RTX) != 0 - && (n_occurrences + added_sets_1 + (added_sets_2 && ! i1_feeds_i3) - > 1)) - /* Fail if we tried to make a new register (we used to abort, but there's - really no reason to). */ - || max_reg_num () != maxreg - /* Fail if we couldn't do something and have a CLOBBER. */ - || GET_CODE (newpat) == CLOBBER - /* Fail if this new pattern is a MULT and we didn't have one before - at the outer level. */ - || (GET_CODE (newpat) == SET && GET_CODE (SET_SRC (newpat)) == MULT - && ! have_mult)) - { - undo_all (); - return 0; - } - - /* If the actions of the earlier insns must be kept - in addition to substituting them into the latest one, - we must make a new PARALLEL for the latest insn - to hold additional the SETs. */ - - if (added_sets_1 || added_sets_2) - { - combine_extras++; - - if (GET_CODE (newpat) == PARALLEL) - { - rtvec old = XVEC (newpat, 0); - total_sets = XVECLEN (newpat, 0) + added_sets_1 + added_sets_2; - newpat = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (total_sets)); - bcopy ((char *) &old->elem[0], (char *) XVEC (newpat, 0)->elem, - sizeof (old->elem[0]) * old->num_elem); - } - else - { - rtx old = newpat; - total_sets = 1 + added_sets_1 + added_sets_2; - newpat = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (total_sets)); - XVECEXP (newpat, 0, 0) = old; - } - - if (added_sets_1) - XVECEXP (newpat, 0, --total_sets) - = (GET_CODE (PATTERN (i1)) == PARALLEL - ? gen_rtx_SET (VOIDmode, i1dest, i1src) : PATTERN (i1)); - - if (added_sets_2) - { - /* If there is no I1, use I2's body as is. We used to also not do - the subst call below if I2 was substituted into I3, - but that could lose a simplification. */ - if (i1 == 0) - XVECEXP (newpat, 0, --total_sets) = i2pat; - else - /* See comment where i2pat is assigned. */ - XVECEXP (newpat, 0, --total_sets) - = subst (i2pat, i1dest, i1src, 0, 0); - } - } - - /* We come here when we are replacing a destination in I2 with the - destination of I3. */ - validate_replacement: - - /* Note which hard regs this insn has as inputs. */ - mark_used_regs_combine (newpat); - - /* Is the result of combination a valid instruction? */ - insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); - - /* If the result isn't valid, see if it is a PARALLEL of two SETs where - the second SET's destination is a register that is unused. In that case, - we just need the first SET. This can occur when simplifying a divmod - insn. We *must* test for this case here because the code below that - splits two independent SETs doesn't handle this case correctly when it - updates the register status. Also check the case where the first - SET's destination is unused. That would not cause incorrect code, but - does cause an unneeded insn to remain. */ - - if (insn_code_number < 0 && GET_CODE (newpat) == PARALLEL - && XVECLEN (newpat, 0) == 2 - && GET_CODE (XVECEXP (newpat, 0, 0)) == SET - && GET_CODE (XVECEXP (newpat, 0, 1)) == SET - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) == REG - && find_reg_note (i3, REG_UNUSED, SET_DEST (XVECEXP (newpat, 0, 1))) - && ! side_effects_p (SET_SRC (XVECEXP (newpat, 0, 1))) - && asm_noperands (newpat) < 0) - { - newpat = XVECEXP (newpat, 0, 0); - insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); - } - - else if (insn_code_number < 0 && GET_CODE (newpat) == PARALLEL - && XVECLEN (newpat, 0) == 2 - && GET_CODE (XVECEXP (newpat, 0, 0)) == SET - && GET_CODE (XVECEXP (newpat, 0, 1)) == SET - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) == REG - && find_reg_note (i3, REG_UNUSED, SET_DEST (XVECEXP (newpat, 0, 0))) - && ! side_effects_p (SET_SRC (XVECEXP (newpat, 0, 0))) - && asm_noperands (newpat) < 0) - { - newpat = XVECEXP (newpat, 0, 1); - insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); - } - - /* If we were combining three insns and the result is a simple SET - with no ASM_OPERANDS that wasn't recognized, try to split it into two - insns. There are two ways to do this. It can be split using a - machine-specific method (like when you have an addition of a large - constant) or by combine in the function find_split_point. */ - - if (i1 && insn_code_number < 0 && GET_CODE (newpat) == SET - && asm_noperands (newpat) < 0) - { - rtx m_split, *split; - rtx ni2dest = i2dest; - - /* See if the MD file can split NEWPAT. If it can't, see if letting it - use I2DEST as a scratch register will help. In the latter case, - convert I2DEST to the mode of the source of NEWPAT if we can. */ - - m_split = split_insns (newpat, i3); - - /* We can only use I2DEST as a scratch reg if it doesn't overlap any - inputs of NEWPAT. */ - - /* ??? If I2DEST is not safe, and I1DEST exists, then it would be - possible to try that as a scratch reg. This would require adding - more code to make it work though. */ - - if (m_split == 0 && ! reg_overlap_mentioned_p (ni2dest, newpat)) - { - /* If I2DEST is a hard register or the only use of a pseudo, - we can change its mode. */ - if (GET_MODE (SET_DEST (newpat)) != GET_MODE (i2dest) - && GET_MODE (SET_DEST (newpat)) != VOIDmode - && GET_CODE (i2dest) == REG - && (REGNO (i2dest) < FIRST_PSEUDO_REGISTER - || (REG_N_SETS (REGNO (i2dest)) == 1 && ! added_sets_2 - && ! REG_USERVAR_P (i2dest)))) - ni2dest = gen_rtx_REG (GET_MODE (SET_DEST (newpat)), - REGNO (i2dest)); - - m_split = split_insns - (gen_rtx_PARALLEL (VOIDmode, - gen_rtvec (2, newpat, - gen_rtx_CLOBBER (VOIDmode, - ni2dest))), - i3); - } - - if (m_split && GET_CODE (m_split) == SEQUENCE - && XVECLEN (m_split, 0) == 2 - && (next_real_insn (i2) == i3 - || ! use_crosses_set_p (PATTERN (XVECEXP (m_split, 0, 0)), - INSN_CUID (i2)))) - { - rtx i2set, i3set; - rtx newi3pat = PATTERN (XVECEXP (m_split, 0, 1)); - newi2pat = PATTERN (XVECEXP (m_split, 0, 0)); - - i3set = single_set (XVECEXP (m_split, 0, 1)); - i2set = single_set (XVECEXP (m_split, 0, 0)); - - /* In case we changed the mode of I2DEST, replace it in the - pseudo-register table here. We can't do it above in case this - code doesn't get executed and we do a split the other way. */ - - if (REGNO (i2dest) >= FIRST_PSEUDO_REGISTER) - SUBST (regno_reg_rtx[REGNO (i2dest)], ni2dest); - - i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); - - /* If I2 or I3 has multiple SETs, we won't know how to track - register status, so don't use these insns. If I2's destination - is used between I2 and I3, we also can't use these insns. */ - - if (i2_code_number >= 0 && i2set && i3set - && (next_real_insn (i2) == i3 - || ! reg_used_between_p (SET_DEST (i2set), i2, i3))) - insn_code_number = recog_for_combine (&newi3pat, i3, - &new_i3_notes); - if (insn_code_number >= 0) - newpat = newi3pat; - - /* It is possible that both insns now set the destination of I3. - If so, we must show an extra use of it. */ - - if (insn_code_number >= 0) - { - rtx new_i3_dest = SET_DEST (i3set); - rtx new_i2_dest = SET_DEST (i2set); - - while (GET_CODE (new_i3_dest) == ZERO_EXTRACT - || GET_CODE (new_i3_dest) == STRICT_LOW_PART - || GET_CODE (new_i3_dest) == SUBREG) - new_i3_dest = XEXP (new_i3_dest, 0); - - while (GET_CODE (new_i2_dest) == ZERO_EXTRACT - || GET_CODE (new_i2_dest) == STRICT_LOW_PART - || GET_CODE (new_i2_dest) == SUBREG) - new_i2_dest = XEXP (new_i2_dest, 0); - - if (GET_CODE (new_i3_dest) == REG - && GET_CODE (new_i2_dest) == REG - && REGNO (new_i3_dest) == REGNO (new_i2_dest)) - REG_N_SETS (REGNO (new_i2_dest))++; - } - } - - /* If we can split it and use I2DEST, go ahead and see if that - helps things be recognized. Verify that none of the registers - are set between I2 and I3. */ - if (insn_code_number < 0 && (split = find_split_point (&newpat, i3)) != 0 -#ifdef HAVE_cc0 - && GET_CODE (i2dest) == REG -#endif - /* We need I2DEST in the proper mode. If it is a hard register - or the only use of a pseudo, we can change its mode. */ - && (GET_MODE (*split) == GET_MODE (i2dest) - || GET_MODE (*split) == VOIDmode - || REGNO (i2dest) < FIRST_PSEUDO_REGISTER - || (REG_N_SETS (REGNO (i2dest)) == 1 && ! added_sets_2 - && ! REG_USERVAR_P (i2dest))) - && (next_real_insn (i2) == i3 - || ! use_crosses_set_p (*split, INSN_CUID (i2))) - /* We can't overwrite I2DEST if its value is still used by - NEWPAT. */ - && ! reg_referenced_p (i2dest, newpat)) - { - rtx newdest = i2dest; - enum rtx_code split_code = GET_CODE (*split); - enum machine_mode split_mode = GET_MODE (*split); - - /* Get NEWDEST as a register in the proper mode. We have already - validated that we can do this. */ - if (GET_MODE (i2dest) != split_mode && split_mode != VOIDmode) - { - newdest = gen_rtx_REG (split_mode, REGNO (i2dest)); - - if (REGNO (i2dest) >= FIRST_PSEUDO_REGISTER) - SUBST (regno_reg_rtx[REGNO (i2dest)], newdest); - } - - /* If *SPLIT is a (mult FOO (const_int pow2)), convert it to - an ASHIFT. This can occur if it was inside a PLUS and hence - appeared to be a memory address. This is a kludge. */ - if (split_code == MULT - && GET_CODE (XEXP (*split, 1)) == CONST_INT - && (i = exact_log2 (INTVAL (XEXP (*split, 1)))) >= 0) - { - SUBST (*split, gen_rtx_combine (ASHIFT, split_mode, - XEXP (*split, 0), GEN_INT (i))); - /* Update split_code because we may not have a multiply - anymore. */ - split_code = GET_CODE (*split); - } - -#ifdef INSN_SCHEDULING - /* If *SPLIT is a paradoxical SUBREG, when we split it, it should - be written as a ZERO_EXTEND. */ - if (split_code == SUBREG && GET_CODE (SUBREG_REG (*split)) == MEM) - SUBST (*split, gen_rtx_combine (ZERO_EXTEND, split_mode, - XEXP (*split, 0))); -#endif - - newi2pat = gen_rtx_combine (SET, VOIDmode, newdest, *split); - SUBST (*split, newdest); - i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); - - /* If the split point was a MULT and we didn't have one before, - don't use one now. */ - if (i2_code_number >= 0 && ! (split_code == MULT && ! have_mult)) - insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); - } - } - - /* Check for a case where we loaded from memory in a narrow mode and - then sign extended it, but we need both registers. In that case, - we have a PARALLEL with both loads from the same memory location. - We can split this into a load from memory followed by a register-register - copy. This saves at least one insn, more if register allocation can - eliminate the copy. - - We cannot do this if the destination of the second assignment is - a register that we have already assumed is zero-extended. Similarly - for a SUBREG of such a register. */ - - else if (i1 && insn_code_number < 0 && asm_noperands (newpat) < 0 - && GET_CODE (newpat) == PARALLEL - && XVECLEN (newpat, 0) == 2 - && GET_CODE (XVECEXP (newpat, 0, 0)) == SET - && GET_CODE (SET_SRC (XVECEXP (newpat, 0, 0))) == SIGN_EXTEND - && GET_CODE (XVECEXP (newpat, 0, 1)) == SET - && rtx_equal_p (SET_SRC (XVECEXP (newpat, 0, 1)), - XEXP (SET_SRC (XVECEXP (newpat, 0, 0)), 0)) - && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)), - INSN_CUID (i2)) - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART - && ! (temp = SET_DEST (XVECEXP (newpat, 0, 1)), - (GET_CODE (temp) == REG - && reg_nonzero_bits[REGNO (temp)] != 0 - && GET_MODE_BITSIZE (GET_MODE (temp)) < BITS_PER_WORD - && GET_MODE_BITSIZE (GET_MODE (temp)) < HOST_BITS_PER_INT - && (reg_nonzero_bits[REGNO (temp)] - != GET_MODE_MASK (word_mode)))) - && ! (GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) == SUBREG - && (temp = SUBREG_REG (SET_DEST (XVECEXP (newpat, 0, 1))), - (GET_CODE (temp) == REG - && reg_nonzero_bits[REGNO (temp)] != 0 - && GET_MODE_BITSIZE (GET_MODE (temp)) < BITS_PER_WORD - && GET_MODE_BITSIZE (GET_MODE (temp)) < HOST_BITS_PER_INT - && (reg_nonzero_bits[REGNO (temp)] - != GET_MODE_MASK (word_mode))))) - && ! reg_overlap_mentioned_p (SET_DEST (XVECEXP (newpat, 0, 1)), - SET_SRC (XVECEXP (newpat, 0, 1))) - && ! find_reg_note (i3, REG_UNUSED, - SET_DEST (XVECEXP (newpat, 0, 0)))) - { - rtx ni2dest; - - newi2pat = XVECEXP (newpat, 0, 0); - ni2dest = SET_DEST (XVECEXP (newpat, 0, 0)); - newpat = XVECEXP (newpat, 0, 1); - SUBST (SET_SRC (newpat), - gen_lowpart_for_combine (GET_MODE (SET_SRC (newpat)), ni2dest)); - i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); - - if (i2_code_number >= 0) - insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); - - if (insn_code_number >= 0) - { - rtx insn; - rtx link; - - /* If we will be able to accept this, we have made a change to the - destination of I3. This can invalidate a LOG_LINKS pointing - to I3. No other part of combine.c makes such a transformation. - - The new I3 will have a destination that was previously the - destination of I1 or I2 and which was used in i2 or I3. Call - distribute_links to make a LOG_LINK from the next use of - that destination. */ - - PATTERN (i3) = newpat; - distribute_links (gen_rtx_INSN_LIST (VOIDmode, i3, NULL_RTX)); - - /* I3 now uses what used to be its destination and which is - now I2's destination. That means we need a LOG_LINK from - I3 to I2. But we used to have one, so we still will. - - However, some later insn might be using I2's dest and have - a LOG_LINK pointing at I3. We must remove this link. - The simplest way to remove the link is to point it at I1, - which we know will be a NOTE. */ - - for (insn = NEXT_INSN (i3); - insn && (this_basic_block == n_basic_blocks - 1 - || insn != BLOCK_HEAD (this_basic_block + 1)); - insn = NEXT_INSN (insn)) - { - if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' - && reg_referenced_p (ni2dest, PATTERN (insn))) - { - for (link = LOG_LINKS (insn); link; - link = XEXP (link, 1)) - if (XEXP (link, 0) == i3) - XEXP (link, 0) = i1; - - break; - } - } - } - } - - /* Similarly, check for a case where we have a PARALLEL of two independent - SETs but we started with three insns. In this case, we can do the sets - as two separate insns. This case occurs when some SET allows two - other insns to combine, but the destination of that SET is still live. */ - - else if (i1 && insn_code_number < 0 && asm_noperands (newpat) < 0 - && GET_CODE (newpat) == PARALLEL - && XVECLEN (newpat, 0) == 2 - && GET_CODE (XVECEXP (newpat, 0, 0)) == SET - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) != ZERO_EXTRACT - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) != STRICT_LOW_PART - && GET_CODE (XVECEXP (newpat, 0, 1)) == SET - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART - && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)), - INSN_CUID (i2)) - /* Don't pass sets with (USE (MEM ...)) dests to the following. */ - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != USE - && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) != USE - && ! reg_referenced_p (SET_DEST (XVECEXP (newpat, 0, 1)), - XVECEXP (newpat, 0, 0)) - && ! reg_referenced_p (SET_DEST (XVECEXP (newpat, 0, 0)), - XVECEXP (newpat, 0, 1))) - { - /* Normally, it doesn't matter which of the two is done first, - but it does if one references cc0. In that case, it has to - be first. */ -#ifdef HAVE_cc0 - if (reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 0))) - { - newi2pat = XVECEXP (newpat, 0, 0); - newpat = XVECEXP (newpat, 0, 1); - } - else -#endif - { - newi2pat = XVECEXP (newpat, 0, 1); - newpat = XVECEXP (newpat, 0, 0); - } - - i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); - - if (i2_code_number >= 0) - insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); - } - - /* If it still isn't recognized, fail and change things back the way they - were. */ - if ((insn_code_number < 0 - /* Is the result a reasonable ASM_OPERANDS? */ - && (! check_asm_operands (newpat) || added_sets_1 || added_sets_2))) - { - undo_all (); - return 0; - } - - /* If we had to change another insn, make sure it is valid also. */ - if (undobuf.other_insn) - { - rtx other_pat = PATTERN (undobuf.other_insn); - rtx new_other_notes; - rtx note, next; - - CLEAR_HARD_REG_SET (newpat_used_regs); - - other_code_number = recog_for_combine (&other_pat, undobuf.other_insn, - &new_other_notes); - - if (other_code_number < 0 && ! check_asm_operands (other_pat)) - { - undo_all (); - return 0; - } - - PATTERN (undobuf.other_insn) = other_pat; - - /* If any of the notes in OTHER_INSN were REG_UNUSED, ensure that they - are still valid. Then add any non-duplicate notes added by - recog_for_combine. */ - for (note = REG_NOTES (undobuf.other_insn); note; note = next) - { - next = XEXP (note, 1); - - if (REG_NOTE_KIND (note) == REG_UNUSED - && ! reg_set_p (XEXP (note, 0), PATTERN (undobuf.other_insn))) - { - if (GET_CODE (XEXP (note, 0)) == REG) - REG_N_DEATHS (REGNO (XEXP (note, 0)))--; - - remove_note (undobuf.other_insn, note); - } - } - - for (note = new_other_notes; note; note = XEXP (note, 1)) - if (GET_CODE (XEXP (note, 0)) == REG) - REG_N_DEATHS (REGNO (XEXP (note, 0)))++; - - distribute_notes (new_other_notes, undobuf.other_insn, - undobuf.other_insn, NULL_RTX, NULL_RTX, NULL_RTX); - } - - /* We now know that we can do this combination. Merge the insns and - update the status of registers and LOG_LINKS. */ - - { - rtx i3notes, i2notes, i1notes = 0; - rtx i3links, i2links, i1links = 0; - rtx midnotes = 0; - register int regno; - /* Compute which registers we expect to eliminate. newi2pat may be setting - either i3dest or i2dest, so we must check it. Also, i1dest may be the - same as i3dest, in which case newi2pat may be setting i1dest. */ - rtx elim_i2 = ((newi2pat && reg_set_p (i2dest, newi2pat)) - || i2dest_in_i2src || i2dest_in_i1src - ? 0 : i2dest); - rtx elim_i1 = (i1 == 0 || i1dest_in_i1src - || (newi2pat && reg_set_p (i1dest, newi2pat)) - ? 0 : i1dest); - - /* Get the old REG_NOTES and LOG_LINKS from all our insns and - clear them. */ - i3notes = REG_NOTES (i3), i3links = LOG_LINKS (i3); - i2notes = REG_NOTES (i2), i2links = LOG_LINKS (i2); - if (i1) - i1notes = REG_NOTES (i1), i1links = LOG_LINKS (i1); - - /* Ensure that we do not have something that should not be shared but - occurs multiple times in the new insns. Check this by first - resetting all the `used' flags and then copying anything is shared. */ - - reset_used_flags (i3notes); - reset_used_flags (i2notes); - reset_used_flags (i1notes); - reset_used_flags (newpat); - reset_used_flags (newi2pat); - if (undobuf.other_insn) - reset_used_flags (PATTERN (undobuf.other_insn)); - - i3notes = copy_rtx_if_shared (i3notes); - i2notes = copy_rtx_if_shared (i2notes); - i1notes = copy_rtx_if_shared (i1notes); - newpat = copy_rtx_if_shared (newpat); - newi2pat = copy_rtx_if_shared (newi2pat); - if (undobuf.other_insn) - reset_used_flags (PATTERN (undobuf.other_insn)); - - INSN_CODE (i3) = insn_code_number; - PATTERN (i3) = newpat; - if (undobuf.other_insn) - INSN_CODE (undobuf.other_insn) = other_code_number; - - /* We had one special case above where I2 had more than one set and - we replaced a destination of one of those sets with the destination - of I3. In that case, we have to update LOG_LINKS of insns later - in this basic block. Note that this (expensive) case is rare. - - Also, in this case, we must pretend that all REG_NOTEs for I2 - actually came from I3, so that REG_UNUSED notes from I2 will be - properly handled. */ - - if (i3_subst_into_i2) - { - for (i = 0; i < XVECLEN (PATTERN (i2), 0); i++) - if (GET_CODE (SET_DEST (XVECEXP (PATTERN (i2), 0, i))) == REG - && SET_DEST (XVECEXP (PATTERN (i2), 0, i)) != i2dest - && ! find_reg_note (i2, REG_UNUSED, - SET_DEST (XVECEXP (PATTERN (i2), 0, i)))) - for (temp = NEXT_INSN (i2); - temp && (this_basic_block == n_basic_blocks - 1 - || BLOCK_HEAD (this_basic_block) != temp); - temp = NEXT_INSN (temp)) - if (temp != i3 && GET_RTX_CLASS (GET_CODE (temp)) == 'i') - for (link = LOG_LINKS (temp); link; link = XEXP (link, 1)) - if (XEXP (link, 0) == i2) - XEXP (link, 0) = i3; - - if (i3notes) - { - rtx link = i3notes; - while (XEXP (link, 1)) - link = XEXP (link, 1); - XEXP (link, 1) = i2notes; - } - else - i3notes = i2notes; - i2notes = 0; - } - - LOG_LINKS (i3) = 0; - REG_NOTES (i3) = 0; - LOG_LINKS (i2) = 0; - REG_NOTES (i2) = 0; - - if (newi2pat) - { - INSN_CODE (i2) = i2_code_number; - PATTERN (i2) = newi2pat; - } - else - { - PUT_CODE (i2, NOTE); - NOTE_LINE_NUMBER (i2) = NOTE_INSN_DELETED; - NOTE_SOURCE_FILE (i2) = 0; - } - - if (i1) - { - LOG_LINKS (i1) = 0; - REG_NOTES (i1) = 0; - PUT_CODE (i1, NOTE); - NOTE_LINE_NUMBER (i1) = NOTE_INSN_DELETED; - NOTE_SOURCE_FILE (i1) = 0; - } - - /* Get death notes for everything that is now used in either I3 or - I2 and used to die in a previous insn. If we built two new - patterns, move from I1 to I2 then I2 to I3 so that we get the - proper movement on registers that I2 modifies. */ - - if (newi2pat) - { - move_deaths (newi2pat, NULL_RTX, INSN_CUID (i1), i2, &midnotes); - move_deaths (newpat, newi2pat, INSN_CUID (i1), i3, &midnotes); - } - else - move_deaths (newpat, NULL_RTX, i1 ? INSN_CUID (i1) : INSN_CUID (i2), - i3, &midnotes); - - /* Distribute all the LOG_LINKS and REG_NOTES from I1, I2, and I3. */ - if (i3notes) - distribute_notes (i3notes, i3, i3, newi2pat ? i2 : NULL_RTX, - elim_i2, elim_i1); - if (i2notes) - distribute_notes (i2notes, i2, i3, newi2pat ? i2 : NULL_RTX, - elim_i2, elim_i1); - if (i1notes) - distribute_notes (i1notes, i1, i3, newi2pat ? i2 : NULL_RTX, - elim_i2, elim_i1); - if (midnotes) - distribute_notes (midnotes, NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, - elim_i2, elim_i1); - - /* Distribute any notes added to I2 or I3 by recog_for_combine. We - know these are REG_UNUSED and want them to go to the desired insn, - so we always pass it as i3. We have not counted the notes in - reg_n_deaths yet, so we need to do so now. */ - - if (newi2pat && new_i2_notes) - { - for (temp = new_i2_notes; temp; temp = XEXP (temp, 1)) - if (GET_CODE (XEXP (temp, 0)) == REG) - REG_N_DEATHS (REGNO (XEXP (temp, 0)))++; - - distribute_notes (new_i2_notes, i2, i2, NULL_RTX, NULL_RTX, NULL_RTX); - } - - if (new_i3_notes) - { - for (temp = new_i3_notes; temp; temp = XEXP (temp, 1)) - if (GET_CODE (XEXP (temp, 0)) == REG) - REG_N_DEATHS (REGNO (XEXP (temp, 0)))++; - - distribute_notes (new_i3_notes, i3, i3, NULL_RTX, NULL_RTX, NULL_RTX); - } - - /* If I3DEST was used in I3SRC, it really died in I3. We may need to - put a REG_DEAD note for it somewhere. If NEWI2PAT exists and sets - I3DEST, the death must be somewhere before I2, not I3. If we passed I3 - in that case, it might delete I2. Similarly for I2 and I1. - Show an additional death due to the REG_DEAD note we make here. If - we discard it in distribute_notes, we will decrement it again. */ - - if (i3dest_killed) - { - if (GET_CODE (i3dest_killed) == REG) - REG_N_DEATHS (REGNO (i3dest_killed))++; - - if (newi2pat && reg_set_p (i3dest_killed, newi2pat)) - distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i3dest_killed, - NULL_RTX), - NULL_RTX, i2, NULL_RTX, elim_i2, elim_i1); - else - distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i3dest_killed, - NULL_RTX), - NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, - elim_i2, elim_i1); - } - - if (i2dest_in_i2src) - { - if (GET_CODE (i2dest) == REG) - REG_N_DEATHS (REGNO (i2dest))++; - - if (newi2pat && reg_set_p (i2dest, newi2pat)) - distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i2dest, NULL_RTX), - NULL_RTX, i2, NULL_RTX, NULL_RTX, NULL_RTX); - else - distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i2dest, NULL_RTX), - NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, - NULL_RTX, NULL_RTX); - } - - if (i1dest_in_i1src) - { - if (GET_CODE (i1dest) == REG) - REG_N_DEATHS (REGNO (i1dest))++; - - if (newi2pat && reg_set_p (i1dest, newi2pat)) - distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i1dest, NULL_RTX), - NULL_RTX, i2, NULL_RTX, NULL_RTX, NULL_RTX); - else - distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i1dest, NULL_RTX), - NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, - NULL_RTX, NULL_RTX); - } - - distribute_links (i3links); - distribute_links (i2links); - distribute_links (i1links); - - if (GET_CODE (i2dest) == REG) - { - rtx link; - rtx i2_insn = 0, i2_val = 0, set; - - /* The insn that used to set this register doesn't exist, and - this life of the register may not exist either. See if one of - I3's links points to an insn that sets I2DEST. If it does, - that is now the last known value for I2DEST. If we don't update - this and I2 set the register to a value that depended on its old - contents, we will get confused. If this insn is used, thing - will be set correctly in combine_instructions. */ - - for (link = LOG_LINKS (i3); link; link = XEXP (link, 1)) - if ((set = single_set (XEXP (link, 0))) != 0 - && rtx_equal_p (i2dest, SET_DEST (set))) - i2_insn = XEXP (link, 0), i2_val = SET_SRC (set); - - record_value_for_reg (i2dest, i2_insn, i2_val); - - /* If the reg formerly set in I2 died only once and that was in I3, - zero its use count so it won't make `reload' do any work. */ - if (! added_sets_2 - && (newi2pat == 0 || ! reg_mentioned_p (i2dest, newi2pat)) - && ! i2dest_in_i2src) - { - regno = REGNO (i2dest); - REG_N_SETS (regno)--; - if (REG_N_SETS (regno) == 0 - && ! REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, - regno)) - REG_N_REFS (regno) = 0; - } - } - - if (i1 && GET_CODE (i1dest) == REG) - { - rtx link; - rtx i1_insn = 0, i1_val = 0, set; - - for (link = LOG_LINKS (i3); link; link = XEXP (link, 1)) - if ((set = single_set (XEXP (link, 0))) != 0 - && rtx_equal_p (i1dest, SET_DEST (set))) - i1_insn = XEXP (link, 0), i1_val = SET_SRC (set); - - record_value_for_reg (i1dest, i1_insn, i1_val); - - regno = REGNO (i1dest); - if (! added_sets_1 && ! i1dest_in_i1src) - { - REG_N_SETS (regno)--; - if (REG_N_SETS (regno) == 0 - && ! REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, - regno)) - REG_N_REFS (regno) = 0; - } - } - - /* Update reg_nonzero_bits et al for any changes that may have been made - to this insn. */ - - note_stores (newpat, set_nonzero_bits_and_sign_copies); - if (newi2pat) - note_stores (newi2pat, set_nonzero_bits_and_sign_copies); - - /* If I3 is now an unconditional jump, ensure that it has a - BARRIER following it since it may have initially been a - conditional jump. It may also be the last nonnote insn. */ - - if ((GET_CODE (newpat) == RETURN || simplejump_p (i3)) - && ((temp = next_nonnote_insn (i3)) == NULL_RTX - || GET_CODE (temp) != BARRIER)) - emit_barrier_after (i3); - } - - combine_successes++; - - /* Clear this here, so that subsequent get_last_value calls are not - affected. */ - subst_prev_insn = NULL_RTX; - - if (added_links_insn - && (newi2pat == 0 || INSN_CUID (added_links_insn) < INSN_CUID (i2)) - && INSN_CUID (added_links_insn) < INSN_CUID (i3)) - return added_links_insn; - else - return newi2pat ? i2 : i3; -} - -/* Undo all the modifications recorded in undobuf. */ - -static void -undo_all () -{ - struct undo *undo, *next; - - for (undo = undobuf.undos; undo; undo = next) - { - next = undo->next; - if (undo->is_int) - *undo->where.i = undo->old_contents.i; - else - *undo->where.r = undo->old_contents.r; - - undo->next = undobuf.frees; - undobuf.frees = undo; - } - - obfree (undobuf.storage); - undobuf.undos = undobuf.previous_undos = 0; - - /* Clear this here, so that subsequent get_last_value calls are not - affected. */ - subst_prev_insn = NULL_RTX; -} - -/* Find the innermost point within the rtx at LOC, possibly LOC itself, - where we have an arithmetic expression and return that point. LOC will - be inside INSN. - - try_combine will call this function to see if an insn can be split into - two insns. */ - -static rtx * -find_split_point (loc, insn) - rtx *loc; - rtx insn; -{ - rtx x = *loc; - enum rtx_code code = GET_CODE (x); - rtx *split; - int len = 0, pos, unsignedp; - rtx inner; - - /* First special-case some codes. */ - switch (code) - { - case SUBREG: -#ifdef INSN_SCHEDULING - /* If we are making a paradoxical SUBREG invalid, it becomes a split - point. */ - if (GET_CODE (SUBREG_REG (x)) == MEM) - return loc; -#endif - return find_split_point (&SUBREG_REG (x), insn); - - case MEM: -#ifdef HAVE_lo_sum - /* If we have (mem (const ..)) or (mem (symbol_ref ...)), split it - using LO_SUM and HIGH. */ - if (GET_CODE (XEXP (x, 0)) == CONST - || GET_CODE (XEXP (x, 0)) == SYMBOL_REF) - { - SUBST (XEXP (x, 0), - gen_rtx_combine (LO_SUM, Pmode, - gen_rtx_combine (HIGH, Pmode, XEXP (x, 0)), - XEXP (x, 0))); - return &XEXP (XEXP (x, 0), 0); - } -#endif - - /* If we have a PLUS whose second operand is a constant and the - address is not valid, perhaps will can split it up using - the machine-specific way to split large constants. We use - the first pseudo-reg (one of the virtual regs) as a placeholder; - it will not remain in the result. */ - if (GET_CODE (XEXP (x, 0)) == PLUS - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && ! memory_address_p (GET_MODE (x), XEXP (x, 0))) - { - rtx reg = regno_reg_rtx[FIRST_PSEUDO_REGISTER]; - rtx seq = split_insns (gen_rtx_SET (VOIDmode, reg, XEXP (x, 0)), - subst_insn); - - /* This should have produced two insns, each of which sets our - placeholder. If the source of the second is a valid address, - we can make put both sources together and make a split point - in the middle. */ - - if (seq && XVECLEN (seq, 0) == 2 - && GET_CODE (XVECEXP (seq, 0, 0)) == INSN - && GET_CODE (PATTERN (XVECEXP (seq, 0, 0))) == SET - && SET_DEST (PATTERN (XVECEXP (seq, 0, 0))) == reg - && ! reg_mentioned_p (reg, - SET_SRC (PATTERN (XVECEXP (seq, 0, 0)))) - && GET_CODE (XVECEXP (seq, 0, 1)) == INSN - && GET_CODE (PATTERN (XVECEXP (seq, 0, 1))) == SET - && SET_DEST (PATTERN (XVECEXP (seq, 0, 1))) == reg - && memory_address_p (GET_MODE (x), - SET_SRC (PATTERN (XVECEXP (seq, 0, 1))))) - { - rtx src1 = SET_SRC (PATTERN (XVECEXP (seq, 0, 0))); - rtx src2 = SET_SRC (PATTERN (XVECEXP (seq, 0, 1))); - - /* Replace the placeholder in SRC2 with SRC1. If we can - find where in SRC2 it was placed, that can become our - split point and we can replace this address with SRC2. - Just try two obvious places. */ - - src2 = replace_rtx (src2, reg, src1); - split = 0; - if (XEXP (src2, 0) == src1) - split = &XEXP (src2, 0); - else if (GET_RTX_FORMAT (GET_CODE (XEXP (src2, 0)))[0] == 'e' - && XEXP (XEXP (src2, 0), 0) == src1) - split = &XEXP (XEXP (src2, 0), 0); - - if (split) - { - SUBST (XEXP (x, 0), src2); - return split; - } - } - - /* If that didn't work, perhaps the first operand is complex and - needs to be computed separately, so make a split point there. - This will occur on machines that just support REG + CONST - and have a constant moved through some previous computation. */ - - else if (GET_RTX_CLASS (GET_CODE (XEXP (XEXP (x, 0), 0))) != 'o' - && ! (GET_CODE (XEXP (XEXP (x, 0), 0)) == SUBREG - && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (XEXP (x, 0), 0)))) - == 'o'))) - return &XEXP (XEXP (x, 0), 0); - } - break; - - case SET: -#ifdef HAVE_cc0 - /* If SET_DEST is CC0 and SET_SRC is not an operand, a COMPARE, or a - ZERO_EXTRACT, the most likely reason why this doesn't match is that - we need to put the operand into a register. So split at that - point. */ - - if (SET_DEST (x) == cc0_rtx - && GET_CODE (SET_SRC (x)) != COMPARE - && GET_CODE (SET_SRC (x)) != ZERO_EXTRACT - && GET_RTX_CLASS (GET_CODE (SET_SRC (x))) != 'o' - && ! (GET_CODE (SET_SRC (x)) == SUBREG - && GET_RTX_CLASS (GET_CODE (SUBREG_REG (SET_SRC (x)))) == 'o')) - return &SET_SRC (x); -#endif - - /* See if we can split SET_SRC as it stands. */ - split = find_split_point (&SET_SRC (x), insn); - if (split && split != &SET_SRC (x)) - return split; - - /* See if we can split SET_DEST as it stands. */ - split = find_split_point (&SET_DEST (x), insn); - if (split && split != &SET_DEST (x)) - return split; - - /* See if this is a bitfield assignment with everything constant. If - so, this is an IOR of an AND, so split it into that. */ - if (GET_CODE (SET_DEST (x)) == ZERO_EXTRACT - && (GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x), 0))) - <= HOST_BITS_PER_WIDE_INT) - && GET_CODE (XEXP (SET_DEST (x), 1)) == CONST_INT - && GET_CODE (XEXP (SET_DEST (x), 2)) == CONST_INT - && GET_CODE (SET_SRC (x)) == CONST_INT - && ((INTVAL (XEXP (SET_DEST (x), 1)) - + INTVAL (XEXP (SET_DEST (x), 2))) - <= GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x), 0)))) - && ! side_effects_p (XEXP (SET_DEST (x), 0))) - { - int pos = INTVAL (XEXP (SET_DEST (x), 2)); - int len = INTVAL (XEXP (SET_DEST (x), 1)); - int src = INTVAL (SET_SRC (x)); - rtx dest = XEXP (SET_DEST (x), 0); - enum machine_mode mode = GET_MODE (dest); - unsigned HOST_WIDE_INT mask = ((HOST_WIDE_INT) 1 << len) - 1; - - if (BITS_BIG_ENDIAN) - pos = GET_MODE_BITSIZE (mode) - len - pos; - - if ((unsigned HOST_WIDE_INT) src == mask) - SUBST (SET_SRC (x), - gen_binary (IOR, mode, dest, GEN_INT (src << pos))); - else - SUBST (SET_SRC (x), - gen_binary (IOR, mode, - gen_binary (AND, mode, dest, - GEN_INT (~ (mask << pos) - & GET_MODE_MASK (mode))), - GEN_INT (src << pos))); - - SUBST (SET_DEST (x), dest); - - split = find_split_point (&SET_SRC (x), insn); - if (split && split != &SET_SRC (x)) - return split; - } - - /* Otherwise, see if this is an operation that we can split into two. - If so, try to split that. */ - code = GET_CODE (SET_SRC (x)); - - switch (code) - { - case AND: - /* If we are AND'ing with a large constant that is only a single - bit and the result is only being used in a context where we - need to know if it is zero or non-zero, replace it with a bit - extraction. This will avoid the large constant, which might - have taken more than one insn to make. If the constant were - not a valid argument to the AND but took only one insn to make, - this is no worse, but if it took more than one insn, it will - be better. */ - - if (GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT - && GET_CODE (XEXP (SET_SRC (x), 0)) == REG - && (pos = exact_log2 (INTVAL (XEXP (SET_SRC (x), 1)))) >= 7 - && GET_CODE (SET_DEST (x)) == REG - && (split = find_single_use (SET_DEST (x), insn, NULL_PTR)) != 0 - && (GET_CODE (*split) == EQ || GET_CODE (*split) == NE) - && XEXP (*split, 0) == SET_DEST (x) - && XEXP (*split, 1) == const0_rtx) - { - rtx extraction = make_extraction (GET_MODE (SET_DEST (x)), - XEXP (SET_SRC (x), 0), - pos, NULL_RTX, 1, 1, 0, 0); - if (extraction != 0) - { - SUBST (SET_SRC (x), extraction); - return find_split_point (loc, insn); - } - } - break; - - case NE: - /* if STORE_FLAG_VALUE is -1, this is (NE X 0) and only one bit of X - is known to be on, this can be converted into a NEG of a shift. */ - if (STORE_FLAG_VALUE == -1 && XEXP (SET_SRC (x), 1) == const0_rtx - && GET_MODE (SET_SRC (x)) == GET_MODE (XEXP (SET_SRC (x), 0)) - && 1 <= (pos = exact_log2 - (nonzero_bits (XEXP (SET_SRC (x), 0), - GET_MODE (XEXP (SET_SRC (x), 0)))))) - { - enum machine_mode mode = GET_MODE (XEXP (SET_SRC (x), 0)); - - SUBST (SET_SRC (x), - gen_rtx_combine (NEG, mode, - gen_rtx_combine (LSHIFTRT, mode, - XEXP (SET_SRC (x), 0), - GEN_INT (pos)))); - - split = find_split_point (&SET_SRC (x), insn); - if (split && split != &SET_SRC (x)) - return split; - } - break; - - case SIGN_EXTEND: - inner = XEXP (SET_SRC (x), 0); - - /* We can't optimize if either mode is a partial integer - mode as we don't know how many bits are significant - in those modes. */ - if (GET_MODE_CLASS (GET_MODE (inner)) == MODE_PARTIAL_INT - || GET_MODE_CLASS (GET_MODE (SET_SRC (x))) == MODE_PARTIAL_INT) - break; - - pos = 0; - len = GET_MODE_BITSIZE (GET_MODE (inner)); - unsignedp = 0; - break; - - case SIGN_EXTRACT: - case ZERO_EXTRACT: - if (GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT - && GET_CODE (XEXP (SET_SRC (x), 2)) == CONST_INT) - { - inner = XEXP (SET_SRC (x), 0); - len = INTVAL (XEXP (SET_SRC (x), 1)); - pos = INTVAL (XEXP (SET_SRC (x), 2)); - - if (BITS_BIG_ENDIAN) - pos = GET_MODE_BITSIZE (GET_MODE (inner)) - len - pos; - unsignedp = (code == ZERO_EXTRACT); - } - break; - - default: - break; - } - - if (len && pos >= 0 && pos + len <= GET_MODE_BITSIZE (GET_MODE (inner))) - { - enum machine_mode mode = GET_MODE (SET_SRC (x)); - - /* For unsigned, we have a choice of a shift followed by an - AND or two shifts. Use two shifts for field sizes where the - constant might be too large. We assume here that we can - always at least get 8-bit constants in an AND insn, which is - true for every current RISC. */ - - if (unsignedp && len <= 8) - { - SUBST (SET_SRC (x), - gen_rtx_combine - (AND, mode, - gen_rtx_combine (LSHIFTRT, mode, - gen_lowpart_for_combine (mode, inner), - GEN_INT (pos)), - GEN_INT (((HOST_WIDE_INT) 1 << len) - 1))); - - split = find_split_point (&SET_SRC (x), insn); - if (split && split != &SET_SRC (x)) - return split; - } - else - { - SUBST (SET_SRC (x), - gen_rtx_combine - (unsignedp ? LSHIFTRT : ASHIFTRT, mode, - gen_rtx_combine (ASHIFT, mode, - gen_lowpart_for_combine (mode, inner), - GEN_INT (GET_MODE_BITSIZE (mode) - - len - pos)), - GEN_INT (GET_MODE_BITSIZE (mode) - len))); - - split = find_split_point (&SET_SRC (x), insn); - if (split && split != &SET_SRC (x)) - return split; - } - } - - /* See if this is a simple operation with a constant as the second - operand. It might be that this constant is out of range and hence - could be used as a split point. */ - if ((GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '2' - || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == 'c' - || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '<') - && CONSTANT_P (XEXP (SET_SRC (x), 1)) - && (GET_RTX_CLASS (GET_CODE (XEXP (SET_SRC (x), 0))) == 'o' - || (GET_CODE (XEXP (SET_SRC (x), 0)) == SUBREG - && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (SET_SRC (x), 0)))) - == 'o')))) - return &XEXP (SET_SRC (x), 1); - - /* Finally, see if this is a simple operation with its first operand - not in a register. The operation might require this operand in a - register, so return it as a split point. We can always do this - because if the first operand were another operation, we would have - already found it as a split point. */ - if ((GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '2' - || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == 'c' - || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '<' - || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '1') - && ! register_operand (XEXP (SET_SRC (x), 0), VOIDmode)) - return &XEXP (SET_SRC (x), 0); - - return 0; - - case AND: - case IOR: - /* We write NOR as (and (not A) (not B)), but if we don't have a NOR, - it is better to write this as (not (ior A B)) so we can split it. - Similarly for IOR. */ - if (GET_CODE (XEXP (x, 0)) == NOT && GET_CODE (XEXP (x, 1)) == NOT) - { - SUBST (*loc, - gen_rtx_combine (NOT, GET_MODE (x), - gen_rtx_combine (code == IOR ? AND : IOR, - GET_MODE (x), - XEXP (XEXP (x, 0), 0), - XEXP (XEXP (x, 1), 0)))); - return find_split_point (loc, insn); - } - - /* Many RISC machines have a large set of logical insns. If the - second operand is a NOT, put it first so we will try to split the - other operand first. */ - if (GET_CODE (XEXP (x, 1)) == NOT) - { - rtx tem = XEXP (x, 0); - SUBST (XEXP (x, 0), XEXP (x, 1)); - SUBST (XEXP (x, 1), tem); - } - break; - - default: - break; - } - - /* Otherwise, select our actions depending on our rtx class. */ - switch (GET_RTX_CLASS (code)) - { - case 'b': /* This is ZERO_EXTRACT and SIGN_EXTRACT. */ - case '3': - split = find_split_point (&XEXP (x, 2), insn); - if (split) - return split; - /* ... fall through ... */ - case '2': - case 'c': - case '<': - split = find_split_point (&XEXP (x, 1), insn); - if (split) - return split; - /* ... fall through ... */ - case '1': - /* Some machines have (and (shift ...) ...) insns. If X is not - an AND, but XEXP (X, 0) is, use it as our split point. */ - if (GET_CODE (x) != AND && GET_CODE (XEXP (x, 0)) == AND) - return &XEXP (x, 0); - - split = find_split_point (&XEXP (x, 0), insn); - if (split) - return split; - return loc; - } - - /* Otherwise, we don't have a split point. */ - return 0; -} - -/* Throughout X, replace FROM with TO, and return the result. - The result is TO if X is FROM; - otherwise the result is X, but its contents may have been modified. - If they were modified, a record was made in undobuf so that - undo_all will (among other things) return X to its original state. - - If the number of changes necessary is too much to record to undo, - the excess changes are not made, so the result is invalid. - The changes already made can still be undone. - undobuf.num_undo is incremented for such changes, so by testing that - the caller can tell whether the result is valid. - - `n_occurrences' is incremented each time FROM is replaced. - - IN_DEST is non-zero if we are processing the SET_DEST of a SET. - - UNIQUE_COPY is non-zero if each substitution must be unique. We do this - by copying if `n_occurrences' is non-zero. */ - -static rtx -subst (x, from, to, in_dest, unique_copy) - register rtx x, from, to; - int in_dest; - int unique_copy; -{ - register enum rtx_code code = GET_CODE (x); - enum machine_mode op0_mode = VOIDmode; - register char *fmt; - register int len, i; - rtx new; - -/* Two expressions are equal if they are identical copies of a shared - RTX or if they are both registers with the same register number - and mode. */ - -#define COMBINE_RTX_EQUAL_P(X,Y) \ - ((X) == (Y) \ - || (GET_CODE (X) == REG && GET_CODE (Y) == REG \ - && REGNO (X) == REGNO (Y) && GET_MODE (X) == GET_MODE (Y))) - - if (! in_dest && COMBINE_RTX_EQUAL_P (x, from)) - { - n_occurrences++; - return (unique_copy && n_occurrences > 1 ? copy_rtx (to) : to); - } - - /* If X and FROM are the same register but different modes, they will - not have been seen as equal above. However, flow.c will make a - LOG_LINKS entry for that case. If we do nothing, we will try to - rerecognize our original insn and, when it succeeds, we will - delete the feeding insn, which is incorrect. - - So force this insn not to match in this (rare) case. */ - if (! in_dest && code == REG && GET_CODE (from) == REG - && REGNO (x) == REGNO (from)) - return gen_rtx_CLOBBER (GET_MODE (x), const0_rtx); - - /* If this is an object, we are done unless it is a MEM or LO_SUM, both - of which may contain things that can be combined. */ - if (code != MEM && code != LO_SUM && GET_RTX_CLASS (code) == 'o') - return x; - - /* It is possible to have a subexpression appear twice in the insn. - Suppose that FROM is a register that appears within TO. - Then, after that subexpression has been scanned once by `subst', - the second time it is scanned, TO may be found. If we were - to scan TO here, we would find FROM within it and create a - self-referent rtl structure which is completely wrong. */ - if (COMBINE_RTX_EQUAL_P (x, to)) - return to; - - /* Parallel asm_operands need special attention because all of the - inputs are shared across the arms. Furthermore, unsharing the - rtl results in recognition failures. Failure to handle this case - specially can result in circular rtl. - - Solve this by doing a normal pass across the first entry of the - parallel, and only processing the SET_DESTs of the subsequent - entries. Ug. */ - - if (code == PARALLEL - && GET_CODE (XVECEXP (x, 0, 0)) == SET - && GET_CODE (SET_SRC (XVECEXP (x, 0, 0))) == ASM_OPERANDS) - { - new = subst (XVECEXP (x, 0, 0), from, to, 0, unique_copy); - - /* If this substitution failed, this whole thing fails. */ - if (GET_CODE (new) == CLOBBER - && XEXP (new, 0) == const0_rtx) - return new; - - SUBST (XVECEXP (x, 0, 0), new); - - for (i = XVECLEN (x, 0) - 1; i >= 1; i--) - { - rtx dest = SET_DEST (XVECEXP (x, 0, i)); - - if (GET_CODE (dest) != REG - && GET_CODE (dest) != CC0 - && GET_CODE (dest) != PC) - { - new = subst (dest, from, to, 0, unique_copy); - - /* If this substitution failed, this whole thing fails. */ - if (GET_CODE (new) == CLOBBER - && XEXP (new, 0) == const0_rtx) - return new; - - SUBST (SET_DEST (XVECEXP (x, 0, i)), new); - } - } - } - else - { - len = GET_RTX_LENGTH (code); - fmt = GET_RTX_FORMAT (code); - - /* We don't need to process a SET_DEST that is a register, CC0, - or PC, so set up to skip this common case. All other cases - where we want to suppress replacing something inside a - SET_SRC are handled via the IN_DEST operand. */ - if (code == SET - && (GET_CODE (SET_DEST (x)) == REG - || GET_CODE (SET_DEST (x)) == CC0 - || GET_CODE (SET_DEST (x)) == PC)) - fmt = "ie"; - - /* Get the mode of operand 0 in case X is now a SIGN_EXTEND of a - constant. */ - if (fmt[0] == 'e') - op0_mode = GET_MODE (XEXP (x, 0)); - - for (i = 0; i < len; i++) - { - if (fmt[i] == 'E') - { - register int j; - for (j = XVECLEN (x, i) - 1; j >= 0; j--) - { - if (COMBINE_RTX_EQUAL_P (XVECEXP (x, i, j), from)) - { - new = (unique_copy && n_occurrences - ? copy_rtx (to) : to); - n_occurrences++; - } - else - { - new = subst (XVECEXP (x, i, j), from, to, 0, - unique_copy); - - /* If this substitution failed, this whole thing - fails. */ - if (GET_CODE (new) == CLOBBER - && XEXP (new, 0) == const0_rtx) - return new; - } - - SUBST (XVECEXP (x, i, j), new); - } - } - else if (fmt[i] == 'e') - { - if (COMBINE_RTX_EQUAL_P (XEXP (x, i), from)) - { - /* In general, don't install a subreg involving two - modes not tieable. It can worsen register - allocation, and can even make invalid reload - insns, since the reg inside may need to be copied - from in the outside mode, and that may be invalid - if it is an fp reg copied in integer mode. - - We allow two exceptions to this: It is valid if - it is inside another SUBREG and the mode of that - SUBREG and the mode of the inside of TO is - tieable and it is valid if X is a SET that copies - FROM to CC0. */ - - if (GET_CODE (to) == SUBREG - && ! MODES_TIEABLE_P (GET_MODE (to), - GET_MODE (SUBREG_REG (to))) - && ! (code == SUBREG - && MODES_TIEABLE_P (GET_MODE (x), - GET_MODE (SUBREG_REG (to)))) -#ifdef HAVE_cc0 - && ! (code == SET && i == 1 && XEXP (x, 0) == cc0_rtx) -#endif - ) - return gen_rtx_CLOBBER (VOIDmode, const0_rtx); - - new = (unique_copy && n_occurrences ? copy_rtx (to) : to); - n_occurrences++; - } - else - /* If we are in a SET_DEST, suppress most cases unless we - have gone inside a MEM, in which case we want to - simplify the address. We assume here that things that - are actually part of the destination have their inner - parts in the first expression. This is true for SUBREG, - STRICT_LOW_PART, and ZERO_EXTRACT, which are the only - things aside from REG and MEM that should appear in a - SET_DEST. */ - new = subst (XEXP (x, i), from, to, - (((in_dest - && (code == SUBREG || code == STRICT_LOW_PART - || code == ZERO_EXTRACT)) - || code == SET) - && i == 0), unique_copy); - - /* If we found that we will have to reject this combination, - indicate that by returning the CLOBBER ourselves, rather than - an expression containing it. This will speed things up as - well as prevent accidents where two CLOBBERs are considered - to be equal, thus producing an incorrect simplification. */ - - if (GET_CODE (new) == CLOBBER && XEXP (new, 0) == const0_rtx) - return new; - - SUBST (XEXP (x, i), new); - } - } - } - - /* Try to simplify X. If the simplification changed the code, it is likely - that further simplification will help, so loop, but limit the number - of repetitions that will be performed. */ - - for (i = 0; i < 4; i++) - { - /* If X is sufficiently simple, don't bother trying to do anything - with it. */ - if (code != CONST_INT && code != REG && code != CLOBBER) - x = simplify_rtx (x, op0_mode, i == 3, in_dest); - - if (GET_CODE (x) == code) - break; - - code = GET_CODE (x); - - /* We no longer know the original mode of operand 0 since we - have changed the form of X) */ - op0_mode = VOIDmode; - } - - return x; -} - -/* Simplify X, a piece of RTL. We just operate on the expression at the - outer level; call `subst' to simplify recursively. Return the new - expression. - - OP0_MODE is the original mode of XEXP (x, 0); LAST is nonzero if this - will be the iteration even if an expression with a code different from - X is returned; IN_DEST is nonzero if we are inside a SET_DEST. */ - -static rtx -simplify_rtx (x, op0_mode, last, in_dest) - rtx x; - enum machine_mode op0_mode; - int last; - int in_dest; -{ - enum rtx_code code = GET_CODE (x); - enum machine_mode mode = GET_MODE (x); - rtx temp; - int i; - - /* If this is a commutative operation, put a constant last and a complex - expression first. We don't need to do this for comparisons here. */ - if (GET_RTX_CLASS (code) == 'c' - && ((CONSTANT_P (XEXP (x, 0)) && GET_CODE (XEXP (x, 1)) != CONST_INT) - || (GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'o' - && GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) != 'o') - || (GET_CODE (XEXP (x, 0)) == SUBREG - && GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 0)))) == 'o' - && GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) != 'o'))) - { - temp = XEXP (x, 0); - SUBST (XEXP (x, 0), XEXP (x, 1)); - SUBST (XEXP (x, 1), temp); - } - - /* If this is a PLUS, MINUS, or MULT, and the first operand is the - sign extension of a PLUS with a constant, reverse the order of the sign - extension and the addition. Note that this not the same as the original - code, but overflow is undefined for signed values. Also note that the - PLUS will have been partially moved "inside" the sign-extension, so that - the first operand of X will really look like: - (ashiftrt (plus (ashift A C4) C5) C4). - We convert this to - (plus (ashiftrt (ashift A C4) C2) C4) - and replace the first operand of X with that expression. Later parts - of this function may simplify the expression further. - - For example, if we start with (mult (sign_extend (plus A C1)) C2), - we swap the SIGN_EXTEND and PLUS. Later code will apply the - distributive law to produce (plus (mult (sign_extend X) C1) C3). - - We do this to simplify address expressions. */ - - if ((code == PLUS || code == MINUS || code == MULT) - && GET_CODE (XEXP (x, 0)) == ASHIFTRT - && GET_CODE (XEXP (XEXP (x, 0), 0)) == PLUS - && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == ASHIFT - && GET_CODE (XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 1)) == CONST_INT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 1) == XEXP (XEXP (x, 0), 1) - && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 1)) == CONST_INT - && (temp = simplify_binary_operation (ASHIFTRT, mode, - XEXP (XEXP (XEXP (x, 0), 0), 1), - XEXP (XEXP (x, 0), 1))) != 0) - { - rtx new - = simplify_shift_const (NULL_RTX, ASHIFT, mode, - XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 0), - INTVAL (XEXP (XEXP (x, 0), 1))); - - new = simplify_shift_const (NULL_RTX, ASHIFTRT, mode, new, - INTVAL (XEXP (XEXP (x, 0), 1))); - - SUBST (XEXP (x, 0), gen_binary (PLUS, mode, new, temp)); - } - - /* If this is a simple operation applied to an IF_THEN_ELSE, try - applying it to the arms of the IF_THEN_ELSE. This often simplifies - things. Check for cases where both arms are testing the same - condition. - - Don't do anything if all operands are very simple. */ - - if (((GET_RTX_CLASS (code) == '2' || GET_RTX_CLASS (code) == 'c' - || GET_RTX_CLASS (code) == '<') - && ((GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) != 'o' - && ! (GET_CODE (XEXP (x, 0)) == SUBREG - && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 0)))) - == 'o'))) - || (GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) != 'o' - && ! (GET_CODE (XEXP (x, 1)) == SUBREG - && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 1)))) - == 'o'))))) - || (GET_RTX_CLASS (code) == '1' - && ((GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) != 'o' - && ! (GET_CODE (XEXP (x, 0)) == SUBREG - && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 0)))) - == 'o')))))) - { - rtx cond, true, false; - - cond = if_then_else_cond (x, &true, &false); - if (cond != 0 - /* If everything is a comparison, what we have is highly unlikely - to be simpler, so don't use it. */ - && ! (GET_RTX_CLASS (code) == '<' - && (GET_RTX_CLASS (GET_CODE (true)) == '<' - || GET_RTX_CLASS (GET_CODE (false)) == '<'))) - { - rtx cop1 = const0_rtx; - enum rtx_code cond_code = simplify_comparison (NE, &cond, &cop1); - - if (cond_code == NE && GET_RTX_CLASS (GET_CODE (cond)) == '<') - return x; - - /* Simplify the alternative arms; this may collapse the true and - false arms to store-flag values. */ - true = subst (true, pc_rtx, pc_rtx, 0, 0); - false = subst (false, pc_rtx, pc_rtx, 0, 0); - - /* Restarting if we generate a store-flag expression will cause - us to loop. Just drop through in this case. */ - - /* If the result values are STORE_FLAG_VALUE and zero, we can - just make the comparison operation. */ - if (true == const_true_rtx && false == const0_rtx) - x = gen_binary (cond_code, mode, cond, cop1); - else if (true == const0_rtx && false == const_true_rtx) - x = gen_binary (reverse_condition (cond_code), mode, cond, cop1); - - /* Likewise, we can make the negate of a comparison operation - if the result values are - STORE_FLAG_VALUE and zero. */ - else if (GET_CODE (true) == CONST_INT - && INTVAL (true) == - STORE_FLAG_VALUE - && false == const0_rtx) - x = gen_unary (NEG, mode, mode, - gen_binary (cond_code, mode, cond, cop1)); - else if (GET_CODE (false) == CONST_INT - && INTVAL (false) == - STORE_FLAG_VALUE - && true == const0_rtx) - x = gen_unary (NEG, mode, mode, - gen_binary (reverse_condition (cond_code), - mode, cond, cop1)); - else - return gen_rtx_IF_THEN_ELSE (mode, - gen_binary (cond_code, VOIDmode, - cond, cop1), - true, false); - - code = GET_CODE (x); - op0_mode = VOIDmode; - } - } - - /* Try to fold this expression in case we have constants that weren't - present before. */ - temp = 0; - switch (GET_RTX_CLASS (code)) - { - case '1': - temp = simplify_unary_operation (code, mode, XEXP (x, 0), op0_mode); - break; - case '<': - temp = simplify_relational_operation (code, op0_mode, - XEXP (x, 0), XEXP (x, 1)); -#ifdef FLOAT_STORE_FLAG_VALUE - if (temp != 0 && GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT) - temp = ((temp == const0_rtx) ? CONST0_RTX (GET_MODE (x)) - : immed_real_const_1 (FLOAT_STORE_FLAG_VALUE, GET_MODE (x))); -#endif - break; - case 'c': - case '2': - temp = simplify_binary_operation (code, mode, XEXP (x, 0), XEXP (x, 1)); - break; - case 'b': - case '3': - temp = simplify_ternary_operation (code, mode, op0_mode, XEXP (x, 0), - XEXP (x, 1), XEXP (x, 2)); - break; - } - - if (temp) - x = temp, code = GET_CODE (temp); - - /* First see if we can apply the inverse distributive law. */ - if (code == PLUS || code == MINUS - || code == AND || code == IOR || code == XOR) - { - x = apply_distributive_law (x); - code = GET_CODE (x); - } - - /* If CODE is an associative operation not otherwise handled, see if we - can associate some operands. This can win if they are constants or - if they are logically related (i.e. (a & b) & a. */ - if ((code == PLUS || code == MINUS - || code == MULT || code == AND || code == IOR || code == XOR - || code == DIV || code == UDIV - || code == SMAX || code == SMIN || code == UMAX || code == UMIN) - && INTEGRAL_MODE_P (mode)) - { - if (GET_CODE (XEXP (x, 0)) == code) - { - rtx other = XEXP (XEXP (x, 0), 0); - rtx inner_op0 = XEXP (XEXP (x, 0), 1); - rtx inner_op1 = XEXP (x, 1); - rtx inner; - - /* Make sure we pass the constant operand if any as the second - one if this is a commutative operation. */ - if (CONSTANT_P (inner_op0) && GET_RTX_CLASS (code) == 'c') - { - rtx tem = inner_op0; - inner_op0 = inner_op1; - inner_op1 = tem; - } - inner = simplify_binary_operation (code == MINUS ? PLUS - : code == DIV ? MULT - : code == UDIV ? MULT - : code, - mode, inner_op0, inner_op1); - - /* For commutative operations, try the other pair if that one - didn't simplify. */ - if (inner == 0 && GET_RTX_CLASS (code) == 'c') - { - other = XEXP (XEXP (x, 0), 1); - inner = simplify_binary_operation (code, mode, - XEXP (XEXP (x, 0), 0), - XEXP (x, 1)); - } - - if (inner) - return gen_binary (code, mode, other, inner); - } - } - - /* A little bit of algebraic simplification here. */ - switch (code) - { - case MEM: - /* Ensure that our address has any ASHIFTs converted to MULT in case - address-recognizing predicates are called later. */ - temp = make_compound_operation (XEXP (x, 0), MEM); - SUBST (XEXP (x, 0), temp); - break; - - case SUBREG: - /* (subreg:A (mem:B X) N) becomes a modified MEM unless the SUBREG - is paradoxical. If we can't do that safely, then it becomes - something nonsensical so that this combination won't take place. */ - - if (GET_CODE (SUBREG_REG (x)) == MEM - && (GET_MODE_SIZE (mode) - <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))) - { - rtx inner = SUBREG_REG (x); - int endian_offset = 0; - /* Don't change the mode of the MEM - if that would change the meaning of the address. */ - if (MEM_VOLATILE_P (SUBREG_REG (x)) - || mode_dependent_address_p (XEXP (inner, 0))) - return gen_rtx_CLOBBER (mode, const0_rtx); - - if (BYTES_BIG_ENDIAN) - { - if (GET_MODE_SIZE (mode) < UNITS_PER_WORD) - endian_offset += UNITS_PER_WORD - GET_MODE_SIZE (mode); - if (GET_MODE_SIZE (GET_MODE (inner)) < UNITS_PER_WORD) - endian_offset -= (UNITS_PER_WORD - - GET_MODE_SIZE (GET_MODE (inner))); - } - /* Note if the plus_constant doesn't make a valid address - then this combination won't be accepted. */ - x = gen_rtx_MEM (mode, - plus_constant (XEXP (inner, 0), - (SUBREG_WORD (x) * UNITS_PER_WORD - + endian_offset))); - RTX_UNCHANGING_P (x) = RTX_UNCHANGING_P (inner); - MEM_COPY_ATTRIBUTES (x, inner); - return x; - } - - /* If we are in a SET_DEST, these other cases can't apply. */ - if (in_dest) - return x; - - /* Changing mode twice with SUBREG => just change it once, - or not at all if changing back to starting mode. */ - if (GET_CODE (SUBREG_REG (x)) == SUBREG) - { - if (mode == GET_MODE (SUBREG_REG (SUBREG_REG (x))) - && SUBREG_WORD (x) == 0 && SUBREG_WORD (SUBREG_REG (x)) == 0) - return SUBREG_REG (SUBREG_REG (x)); - - SUBST_INT (SUBREG_WORD (x), - SUBREG_WORD (x) + SUBREG_WORD (SUBREG_REG (x))); - SUBST (SUBREG_REG (x), SUBREG_REG (SUBREG_REG (x))); - } - - /* SUBREG of a hard register => just change the register number - and/or mode. If the hard register is not valid in that mode, - suppress this combination. If the hard register is the stack, - frame, or argument pointer, leave this as a SUBREG. */ - - if (GET_CODE (SUBREG_REG (x)) == REG - && REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER - && REGNO (SUBREG_REG (x)) != FRAME_POINTER_REGNUM -#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM - && REGNO (SUBREG_REG (x)) != HARD_FRAME_POINTER_REGNUM -#endif -#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM - && REGNO (SUBREG_REG (x)) != ARG_POINTER_REGNUM -#endif - && REGNO (SUBREG_REG (x)) != STACK_POINTER_REGNUM) - { - if (HARD_REGNO_MODE_OK (REGNO (SUBREG_REG (x)) + SUBREG_WORD (x), - mode)) - return gen_rtx_REG (mode, - REGNO (SUBREG_REG (x)) + SUBREG_WORD (x)); - else - return gen_rtx_CLOBBER (mode, const0_rtx); - } - - /* For a constant, try to pick up the part we want. Handle a full - word and low-order part. Only do this if we are narrowing - the constant; if it is being widened, we have no idea what - the extra bits will have been set to. */ - - if (CONSTANT_P (SUBREG_REG (x)) && op0_mode != VOIDmode - && GET_MODE_SIZE (mode) == UNITS_PER_WORD - && GET_MODE_SIZE (op0_mode) > UNITS_PER_WORD - && GET_MODE_CLASS (mode) == MODE_INT) - { - temp = operand_subword (SUBREG_REG (x), SUBREG_WORD (x), - 0, op0_mode); - if (temp) - return temp; - } - - /* If we want a subreg of a constant, at offset 0, - take the low bits. On a little-endian machine, that's - always valid. On a big-endian machine, it's valid - only if the constant's mode fits in one word. Note that we - cannot use subreg_lowpart_p since SUBREG_REG may be VOIDmode. */ - if (CONSTANT_P (SUBREG_REG (x)) - && ((GET_MODE_SIZE (op0_mode) <= UNITS_PER_WORD - || ! WORDS_BIG_ENDIAN) - ? SUBREG_WORD (x) == 0 - : (SUBREG_WORD (x) - == ((GET_MODE_SIZE (op0_mode) - - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD)) - / UNITS_PER_WORD))) - && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (op0_mode) - && (! WORDS_BIG_ENDIAN - || GET_MODE_BITSIZE (op0_mode) <= BITS_PER_WORD)) - return gen_lowpart_for_combine (mode, SUBREG_REG (x)); - - /* A paradoxical SUBREG of a VOIDmode constant is the same constant, - since we are saying that the high bits don't matter. */ - if (CONSTANT_P (SUBREG_REG (x)) && GET_MODE (SUBREG_REG (x)) == VOIDmode - && GET_MODE_SIZE (mode) > GET_MODE_SIZE (op0_mode)) - return SUBREG_REG (x); - - /* Note that we cannot do any narrowing for non-constants since - we might have been counting on using the fact that some bits were - zero. We now do this in the SET. */ - - break; - - case NOT: - /* (not (plus X -1)) can become (neg X). */ - if (GET_CODE (XEXP (x, 0)) == PLUS - && XEXP (XEXP (x, 0), 1) == constm1_rtx) - return gen_rtx_combine (NEG, mode, XEXP (XEXP (x, 0), 0)); - - /* Similarly, (not (neg X)) is (plus X -1). */ - if (GET_CODE (XEXP (x, 0)) == NEG) - return gen_rtx_combine (PLUS, mode, XEXP (XEXP (x, 0), 0), - constm1_rtx); - - /* (not (xor X C)) for C constant is (xor X D) with D = ~ C. */ - if (GET_CODE (XEXP (x, 0)) == XOR - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && (temp = simplify_unary_operation (NOT, mode, - XEXP (XEXP (x, 0), 1), - mode)) != 0) - return gen_binary (XOR, mode, XEXP (XEXP (x, 0), 0), temp); - - /* (not (ashift 1 X)) is (rotate ~1 X). We used to do this for operands - other than 1, but that is not valid. We could do a similar - simplification for (not (lshiftrt C X)) where C is just the sign bit, - but this doesn't seem common enough to bother with. */ - if (GET_CODE (XEXP (x, 0)) == ASHIFT - && XEXP (XEXP (x, 0), 0) == const1_rtx) - return gen_rtx_ROTATE (mode, gen_unary (NOT, mode, mode, const1_rtx), - XEXP (XEXP (x, 0), 1)); - - if (GET_CODE (XEXP (x, 0)) == SUBREG - && subreg_lowpart_p (XEXP (x, 0)) - && (GET_MODE_SIZE (GET_MODE (XEXP (x, 0))) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (x, 0))))) - && GET_CODE (SUBREG_REG (XEXP (x, 0))) == ASHIFT - && XEXP (SUBREG_REG (XEXP (x, 0)), 0) == const1_rtx) - { - enum machine_mode inner_mode = GET_MODE (SUBREG_REG (XEXP (x, 0))); - - x = gen_rtx_ROTATE (inner_mode, - gen_unary (NOT, inner_mode, inner_mode, - const1_rtx), - XEXP (SUBREG_REG (XEXP (x, 0)), 1)); - return gen_lowpart_for_combine (mode, x); - } - - /* If STORE_FLAG_VALUE is -1, (not (comparison foo bar)) can be done by - reversing the comparison code if valid. */ - if (STORE_FLAG_VALUE == -1 - && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == '<' - && reversible_comparison_p (XEXP (x, 0))) - return gen_rtx_combine (reverse_condition (GET_CODE (XEXP (x, 0))), - mode, XEXP (XEXP (x, 0), 0), - XEXP (XEXP (x, 0), 1)); - - /* (ashiftrt foo C) where C is the number of bits in FOO minus 1 - is (lt foo (const_int 0)) if STORE_FLAG_VALUE is -1, so we can - perform the above simplification. */ - - if (STORE_FLAG_VALUE == -1 - && XEXP (x, 1) == const1_rtx - && GET_CODE (XEXP (x, 0)) == ASHIFTRT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (x, 0), 1)) == GET_MODE_BITSIZE (mode) - 1) - return gen_rtx_combine (GE, mode, XEXP (XEXP (x, 0), 0), const0_rtx); - - /* Apply De Morgan's laws to reduce number of patterns for machines - with negating logical insns (and-not, nand, etc.). If result has - only one NOT, put it first, since that is how the patterns are - coded. */ - - if (GET_CODE (XEXP (x, 0)) == IOR || GET_CODE (XEXP (x, 0)) == AND) - { - rtx in1 = XEXP (XEXP (x, 0), 0), in2 = XEXP (XEXP (x, 0), 1); - - if (GET_CODE (in1) == NOT) - in1 = XEXP (in1, 0); - else - in1 = gen_rtx_combine (NOT, GET_MODE (in1), in1); - - if (GET_CODE (in2) == NOT) - in2 = XEXP (in2, 0); - else if (GET_CODE (in2) == CONST_INT - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) - in2 = GEN_INT (GET_MODE_MASK (mode) & ~ INTVAL (in2)); - else - in2 = gen_rtx_combine (NOT, GET_MODE (in2), in2); - - if (GET_CODE (in2) == NOT) - { - rtx tem = in2; - in2 = in1; in1 = tem; - } - - return gen_rtx_combine (GET_CODE (XEXP (x, 0)) == IOR ? AND : IOR, - mode, in1, in2); - } - break; - - case NEG: - /* (neg (plus X 1)) can become (not X). */ - if (GET_CODE (XEXP (x, 0)) == PLUS - && XEXP (XEXP (x, 0), 1) == const1_rtx) - return gen_rtx_combine (NOT, mode, XEXP (XEXP (x, 0), 0)); - - /* Similarly, (neg (not X)) is (plus X 1). */ - if (GET_CODE (XEXP (x, 0)) == NOT) - return plus_constant (XEXP (XEXP (x, 0), 0), 1); - - /* (neg (minus X Y)) can become (minus Y X). */ - if (GET_CODE (XEXP (x, 0)) == MINUS - && (! FLOAT_MODE_P (mode) - /* x-y != -(y-x) with IEEE floating point. */ - || TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT - || flag_fast_math)) - return gen_binary (MINUS, mode, XEXP (XEXP (x, 0), 1), - XEXP (XEXP (x, 0), 0)); - - /* (neg (xor A 1)) is (plus A -1) if A is known to be either 0 or 1. */ - if (GET_CODE (XEXP (x, 0)) == XOR && XEXP (XEXP (x, 0), 1) == const1_rtx - && nonzero_bits (XEXP (XEXP (x, 0), 0), mode) == 1) - return gen_binary (PLUS, mode, XEXP (XEXP (x, 0), 0), constm1_rtx); - - /* NEG commutes with ASHIFT since it is multiplication. Only do this - if we can then eliminate the NEG (e.g., - if the operand is a constant). */ - - if (GET_CODE (XEXP (x, 0)) == ASHIFT) - { - temp = simplify_unary_operation (NEG, mode, - XEXP (XEXP (x, 0), 0), mode); - if (temp) - { - SUBST (XEXP (XEXP (x, 0), 0), temp); - return XEXP (x, 0); - } - } - - temp = expand_compound_operation (XEXP (x, 0)); - - /* For C equal to the width of MODE minus 1, (neg (ashiftrt X C)) can be - replaced by (lshiftrt X C). This will convert - (neg (sign_extract X 1 Y)) to (zero_extract X 1 Y). */ - - if (GET_CODE (temp) == ASHIFTRT - && GET_CODE (XEXP (temp, 1)) == CONST_INT - && INTVAL (XEXP (temp, 1)) == GET_MODE_BITSIZE (mode) - 1) - return simplify_shift_const (temp, LSHIFTRT, mode, XEXP (temp, 0), - INTVAL (XEXP (temp, 1))); - - /* If X has only a single bit that might be nonzero, say, bit I, convert - (neg X) to (ashiftrt (ashift X C-I) C-I) where C is the bitsize of - MODE minus 1. This will convert (neg (zero_extract X 1 Y)) to - (sign_extract X 1 Y). But only do this if TEMP isn't a register - or a SUBREG of one since we'd be making the expression more - complex if it was just a register. */ - - if (GET_CODE (temp) != REG - && ! (GET_CODE (temp) == SUBREG - && GET_CODE (SUBREG_REG (temp)) == REG) - && (i = exact_log2 (nonzero_bits (temp, mode))) >= 0) - { - rtx temp1 = simplify_shift_const - (NULL_RTX, ASHIFTRT, mode, - simplify_shift_const (NULL_RTX, ASHIFT, mode, temp, - GET_MODE_BITSIZE (mode) - 1 - i), - GET_MODE_BITSIZE (mode) - 1 - i); - - /* If all we did was surround TEMP with the two shifts, we - haven't improved anything, so don't use it. Otherwise, - we are better off with TEMP1. */ - if (GET_CODE (temp1) != ASHIFTRT - || GET_CODE (XEXP (temp1, 0)) != ASHIFT - || XEXP (XEXP (temp1, 0), 0) != temp) - return temp1; - } - break; - - case TRUNCATE: - /* We can't handle truncation to a partial integer mode here - because we don't know the real bitsize of the partial - integer mode. */ - if (GET_MODE_CLASS (mode) == MODE_PARTIAL_INT) - break; - - if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode), - GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))))) - SUBST (XEXP (x, 0), - force_to_mode (XEXP (x, 0), GET_MODE (XEXP (x, 0)), - GET_MODE_MASK (mode), NULL_RTX, 0)); - - /* (truncate:SI ({sign,zero}_extend:DI foo:SI)) == foo:SI. */ - if ((GET_CODE (XEXP (x, 0)) == SIGN_EXTEND - || GET_CODE (XEXP (x, 0)) == ZERO_EXTEND) - && GET_MODE (XEXP (XEXP (x, 0), 0)) == mode) - return XEXP (XEXP (x, 0), 0); - - /* (truncate:SI (OP:DI ({sign,zero}_extend:DI foo:SI))) is - (OP:SI foo:SI) if OP is NEG or ABS. */ - if ((GET_CODE (XEXP (x, 0)) == ABS - || GET_CODE (XEXP (x, 0)) == NEG) - && (GET_CODE (XEXP (XEXP (x, 0), 0)) == SIGN_EXTEND - || GET_CODE (XEXP (XEXP (x, 0), 0)) == ZERO_EXTEND) - && GET_MODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == mode) - return gen_unary (GET_CODE (XEXP (x, 0)), mode, mode, - XEXP (XEXP (XEXP (x, 0), 0), 0)); - - /* (truncate:SI (subreg:DI (truncate:SI X) 0)) is - (truncate:SI x). */ - if (GET_CODE (XEXP (x, 0)) == SUBREG - && GET_CODE (SUBREG_REG (XEXP (x, 0))) == TRUNCATE - && subreg_lowpart_p (XEXP (x, 0))) - return SUBREG_REG (XEXP (x, 0)); - - /* If we know that the value is already truncated, we can - replace the TRUNCATE with a SUBREG if TRULY_NOOP_TRUNCATION is - nonzero for the corresponding modes. */ - if (TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode), - GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))) - && num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0))) - >= GET_MODE_BITSIZE (mode) + 1) - return gen_lowpart_for_combine (mode, XEXP (x, 0)); - - /* A truncate of a comparison can be replaced with a subreg if - STORE_FLAG_VALUE permits. This is like the previous test, - but it works even if the comparison is done in a mode larger - than HOST_BITS_PER_WIDE_INT. */ - if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == '<' - && ((HOST_WIDE_INT) STORE_FLAG_VALUE &~ GET_MODE_MASK (mode)) == 0) - return gen_lowpart_for_combine (mode, XEXP (x, 0)); - - /* Similarly, a truncate of a register whose value is a - comparison can be replaced with a subreg if STORE_FLAG_VALUE - permits. */ - if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && ((HOST_WIDE_INT) STORE_FLAG_VALUE &~ GET_MODE_MASK (mode)) == 0 - && (temp = get_last_value (XEXP (x, 0))) - && GET_RTX_CLASS (GET_CODE (temp)) == '<') - return gen_lowpart_for_combine (mode, XEXP (x, 0)); - - break; - - case FLOAT_TRUNCATE: - /* (float_truncate:SF (float_extend:DF foo:SF)) = foo:SF. */ - if (GET_CODE (XEXP (x, 0)) == FLOAT_EXTEND - && GET_MODE (XEXP (XEXP (x, 0), 0)) == mode) - return XEXP (XEXP (x, 0), 0); - - /* (float_truncate:SF (OP:DF (float_extend:DF foo:sf))) is - (OP:SF foo:SF) if OP is NEG or ABS. */ - if ((GET_CODE (XEXP (x, 0)) == ABS - || GET_CODE (XEXP (x, 0)) == NEG) - && GET_CODE (XEXP (XEXP (x, 0), 0)) == FLOAT_EXTEND - && GET_MODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == mode) - return gen_unary (GET_CODE (XEXP (x, 0)), mode, mode, - XEXP (XEXP (XEXP (x, 0), 0), 0)); - - /* (float_truncate:SF (subreg:DF (float_truncate:SF X) 0)) - is (float_truncate:SF x). */ - if (GET_CODE (XEXP (x, 0)) == SUBREG - && subreg_lowpart_p (XEXP (x, 0)) - && GET_CODE (SUBREG_REG (XEXP (x, 0))) == FLOAT_TRUNCATE) - return SUBREG_REG (XEXP (x, 0)); - break; - -#ifdef HAVE_cc0 - case COMPARE: - /* Convert (compare FOO (const_int 0)) to FOO unless we aren't - using cc0, in which case we want to leave it as a COMPARE - so we can distinguish it from a register-register-copy. */ - if (XEXP (x, 1) == const0_rtx) - return XEXP (x, 0); - - /* In IEEE floating point, x-0 is not the same as x. */ - if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT - || ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0))) - || flag_fast_math) - && XEXP (x, 1) == CONST0_RTX (GET_MODE (XEXP (x, 0)))) - return XEXP (x, 0); - break; -#endif - - case CONST: - /* (const (const X)) can become (const X). Do it this way rather than - returning the inner CONST since CONST can be shared with a - REG_EQUAL note. */ - if (GET_CODE (XEXP (x, 0)) == CONST) - SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); - break; - -#ifdef HAVE_lo_sum - case LO_SUM: - /* Convert (lo_sum (high FOO) FOO) to FOO. This is necessary so we - can add in an offset. find_split_point will split this address up - again if it doesn't match. */ - if (GET_CODE (XEXP (x, 0)) == HIGH - && rtx_equal_p (XEXP (XEXP (x, 0), 0), XEXP (x, 1))) - return XEXP (x, 1); - break; -#endif - - case PLUS: - /* If we have (plus (plus (A const) B)), associate it so that CONST is - outermost. That's because that's the way indexed addresses are - supposed to appear. This code used to check many more cases, but - they are now checked elsewhere. */ - if (GET_CODE (XEXP (x, 0)) == PLUS - && CONSTANT_ADDRESS_P (XEXP (XEXP (x, 0), 1))) - return gen_binary (PLUS, mode, - gen_binary (PLUS, mode, XEXP (XEXP (x, 0), 0), - XEXP (x, 1)), - XEXP (XEXP (x, 0), 1)); - - /* (plus (xor (and <foo> (const_int pow2 - 1)) <c>) <-c>) - when c is (const_int (pow2 + 1) / 2) is a sign extension of a - bit-field and can be replaced by either a sign_extend or a - sign_extract. The `and' may be a zero_extend. */ - if (GET_CODE (XEXP (x, 0)) == XOR - && GET_CODE (XEXP (x, 1)) == CONST_INT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) == - INTVAL (XEXP (XEXP (x, 0), 1)) - && (i = exact_log2 (INTVAL (XEXP (XEXP (x, 0), 1)))) >= 0 - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && ((GET_CODE (XEXP (XEXP (x, 0), 0)) == AND - && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 1)) == CONST_INT - && (INTVAL (XEXP (XEXP (XEXP (x, 0), 0), 1)) - == ((HOST_WIDE_INT) 1 << (i + 1)) - 1)) - || (GET_CODE (XEXP (XEXP (x, 0), 0)) == ZERO_EXTEND - && (GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (XEXP (x, 0), 0), 0))) - == i + 1)))) - return simplify_shift_const - (NULL_RTX, ASHIFTRT, mode, - simplify_shift_const (NULL_RTX, ASHIFT, mode, - XEXP (XEXP (XEXP (x, 0), 0), 0), - GET_MODE_BITSIZE (mode) - (i + 1)), - GET_MODE_BITSIZE (mode) - (i + 1)); - - /* (plus (comparison A B) C) can become (neg (rev-comp A B)) if - C is 1 and STORE_FLAG_VALUE is -1 or if C is -1 and STORE_FLAG_VALUE - is 1. This produces better code than the alternative immediately - below. */ - if (GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == '<' - && reversible_comparison_p (XEXP (x, 0)) - && ((STORE_FLAG_VALUE == -1 && XEXP (x, 1) == const1_rtx) - || (STORE_FLAG_VALUE == 1 && XEXP (x, 1) == constm1_rtx))) - return - gen_unary (NEG, mode, mode, - gen_binary (reverse_condition (GET_CODE (XEXP (x, 0))), - mode, XEXP (XEXP (x, 0), 0), - XEXP (XEXP (x, 0), 1))); - - /* If only the low-order bit of X is possibly nonzero, (plus x -1) - can become (ashiftrt (ashift (xor x 1) C) C) where C is - the bitsize of the mode - 1. This allows simplification of - "a = (b & 8) == 0;" */ - if (XEXP (x, 1) == constm1_rtx - && GET_CODE (XEXP (x, 0)) != REG - && ! (GET_CODE (XEXP (x,0)) == SUBREG - && GET_CODE (SUBREG_REG (XEXP (x, 0))) == REG) - && nonzero_bits (XEXP (x, 0), mode) == 1) - return simplify_shift_const (NULL_RTX, ASHIFTRT, mode, - simplify_shift_const (NULL_RTX, ASHIFT, mode, - gen_rtx_combine (XOR, mode, - XEXP (x, 0), const1_rtx), - GET_MODE_BITSIZE (mode) - 1), - GET_MODE_BITSIZE (mode) - 1); - - /* If we are adding two things that have no bits in common, convert - the addition into an IOR. This will often be further simplified, - for example in cases like ((a & 1) + (a & 2)), which can - become a & 3. */ - - if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (XEXP (x, 0), mode) - & nonzero_bits (XEXP (x, 1), mode)) == 0) - return gen_binary (IOR, mode, XEXP (x, 0), XEXP (x, 1)); - break; - - case MINUS: - /* If STORE_FLAG_VALUE is 1, (minus 1 (comparison foo bar)) can be done - by reversing the comparison code if valid. */ - if (STORE_FLAG_VALUE == 1 - && XEXP (x, 0) == const1_rtx - && GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) == '<' - && reversible_comparison_p (XEXP (x, 1))) - return gen_binary (reverse_condition (GET_CODE (XEXP (x, 1))), - mode, XEXP (XEXP (x, 1), 0), - XEXP (XEXP (x, 1), 1)); - - /* (minus <foo> (and <foo> (const_int -pow2))) becomes - (and <foo> (const_int pow2-1)) */ - if (GET_CODE (XEXP (x, 1)) == AND - && GET_CODE (XEXP (XEXP (x, 1), 1)) == CONST_INT - && exact_log2 (- INTVAL (XEXP (XEXP (x, 1), 1))) >= 0 - && rtx_equal_p (XEXP (XEXP (x, 1), 0), XEXP (x, 0))) - return simplify_and_const_int (NULL_RTX, mode, XEXP (x, 0), - - INTVAL (XEXP (XEXP (x, 1), 1)) - 1); - - /* Canonicalize (minus A (plus B C)) to (minus (minus A B) C) for - integers. */ - if (GET_CODE (XEXP (x, 1)) == PLUS && INTEGRAL_MODE_P (mode)) - return gen_binary (MINUS, mode, - gen_binary (MINUS, mode, XEXP (x, 0), - XEXP (XEXP (x, 1), 0)), - XEXP (XEXP (x, 1), 1)); - break; - - case MULT: - /* If we have (mult (plus A B) C), apply the distributive law and then - the inverse distributive law to see if things simplify. This - occurs mostly in addresses, often when unrolling loops. */ - - if (GET_CODE (XEXP (x, 0)) == PLUS) - { - x = apply_distributive_law - (gen_binary (PLUS, mode, - gen_binary (MULT, mode, - XEXP (XEXP (x, 0), 0), XEXP (x, 1)), - gen_binary (MULT, mode, - XEXP (XEXP (x, 0), 1), XEXP (x, 1)))); - - if (GET_CODE (x) != MULT) - return x; - } - break; - - case UDIV: - /* If this is a divide by a power of two, treat it as a shift if - its first operand is a shift. */ - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && (i = exact_log2 (INTVAL (XEXP (x, 1)))) >= 0 - && (GET_CODE (XEXP (x, 0)) == ASHIFT - || GET_CODE (XEXP (x, 0)) == LSHIFTRT - || GET_CODE (XEXP (x, 0)) == ASHIFTRT - || GET_CODE (XEXP (x, 0)) == ROTATE - || GET_CODE (XEXP (x, 0)) == ROTATERT)) - return simplify_shift_const (NULL_RTX, LSHIFTRT, mode, XEXP (x, 0), i); - break; - - case EQ: case NE: - case GT: case GTU: case GE: case GEU: - case LT: case LTU: case LE: case LEU: - /* If the first operand is a condition code, we can't do anything - with it. */ - if (GET_CODE (XEXP (x, 0)) == COMPARE - || (GET_MODE_CLASS (GET_MODE (XEXP (x, 0))) != MODE_CC -#ifdef HAVE_cc0 - && XEXP (x, 0) != cc0_rtx -#endif - )) - { - rtx op0 = XEXP (x, 0); - rtx op1 = XEXP (x, 1); - enum rtx_code new_code; - - if (GET_CODE (op0) == COMPARE) - op1 = XEXP (op0, 1), op0 = XEXP (op0, 0); - - /* Simplify our comparison, if possible. */ - new_code = simplify_comparison (code, &op0, &op1); - - /* If STORE_FLAG_VALUE is 1, we can convert (ne x 0) to simply X - if only the low-order bit is possibly nonzero in X (such as when - X is a ZERO_EXTRACT of one bit). Similarly, we can convert EQ to - (xor X 1) or (minus 1 X); we use the former. Finally, if X is - known to be either 0 or -1, NE becomes a NEG and EQ becomes - (plus X 1). - - Remove any ZERO_EXTRACT we made when thinking this was a - comparison. It may now be simpler to use, e.g., an AND. If a - ZERO_EXTRACT is indeed appropriate, it will be placed back by - the call to make_compound_operation in the SET case. */ - - if (STORE_FLAG_VALUE == 1 - && new_code == NE && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx && nonzero_bits (op0, mode) == 1) - return gen_lowpart_for_combine (mode, - expand_compound_operation (op0)); - - else if (STORE_FLAG_VALUE == 1 - && new_code == NE && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx - && (num_sign_bit_copies (op0, mode) - == GET_MODE_BITSIZE (mode))) - { - op0 = expand_compound_operation (op0); - return gen_unary (NEG, mode, mode, - gen_lowpart_for_combine (mode, op0)); - } - - else if (STORE_FLAG_VALUE == 1 - && new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx - && nonzero_bits (op0, mode) == 1) - { - op0 = expand_compound_operation (op0); - return gen_binary (XOR, mode, - gen_lowpart_for_combine (mode, op0), - const1_rtx); - } - - else if (STORE_FLAG_VALUE == 1 - && new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx - && (num_sign_bit_copies (op0, mode) - == GET_MODE_BITSIZE (mode))) - { - op0 = expand_compound_operation (op0); - return plus_constant (gen_lowpart_for_combine (mode, op0), 1); - } - - /* If STORE_FLAG_VALUE is -1, we have cases similar to - those above. */ - if (STORE_FLAG_VALUE == -1 - && new_code == NE && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx - && (num_sign_bit_copies (op0, mode) - == GET_MODE_BITSIZE (mode))) - return gen_lowpart_for_combine (mode, - expand_compound_operation (op0)); - - else if (STORE_FLAG_VALUE == -1 - && new_code == NE && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx - && nonzero_bits (op0, mode) == 1) - { - op0 = expand_compound_operation (op0); - return gen_unary (NEG, mode, mode, - gen_lowpart_for_combine (mode, op0)); - } - - else if (STORE_FLAG_VALUE == -1 - && new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx - && (num_sign_bit_copies (op0, mode) - == GET_MODE_BITSIZE (mode))) - { - op0 = expand_compound_operation (op0); - return gen_unary (NOT, mode, mode, - gen_lowpart_for_combine (mode, op0)); - } - - /* If X is 0/1, (eq X 0) is X-1. */ - else if (STORE_FLAG_VALUE == -1 - && new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT - && op1 == const0_rtx - && nonzero_bits (op0, mode) == 1) - { - op0 = expand_compound_operation (op0); - return plus_constant (gen_lowpart_for_combine (mode, op0), -1); - } - - /* If STORE_FLAG_VALUE says to just test the sign bit and X has just - one bit that might be nonzero, we can convert (ne x 0) to - (ashift x c) where C puts the bit in the sign bit. Remove any - AND with STORE_FLAG_VALUE when we are done, since we are only - going to test the sign bit. */ - if (new_code == NE && GET_MODE_CLASS (mode) == MODE_INT - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && ((STORE_FLAG_VALUE & GET_MODE_MASK (mode)) - == (unsigned HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE(mode)-1)) - && op1 == const0_rtx - && mode == GET_MODE (op0) - && (i = exact_log2 (nonzero_bits (op0, mode))) >= 0) - { - x = simplify_shift_const (NULL_RTX, ASHIFT, mode, - expand_compound_operation (op0), - GET_MODE_BITSIZE (mode) - 1 - i); - if (GET_CODE (x) == AND && XEXP (x, 1) == const_true_rtx) - return XEXP (x, 0); - else - return x; - } - - /* If the code changed, return a whole new comparison. */ - if (new_code != code) - return gen_rtx_combine (new_code, mode, op0, op1); - - /* Otherwise, keep this operation, but maybe change its operands. - This also converts (ne (compare FOO BAR) 0) to (ne FOO BAR). */ - SUBST (XEXP (x, 0), op0); - SUBST (XEXP (x, 1), op1); - } - break; - - case IF_THEN_ELSE: - return simplify_if_then_else (x); - - case ZERO_EXTRACT: - case SIGN_EXTRACT: - case ZERO_EXTEND: - case SIGN_EXTEND: - /* If we are processing SET_DEST, we are done. */ - if (in_dest) - return x; - - return expand_compound_operation (x); - - case SET: - return simplify_set (x); - - case AND: - case IOR: - case XOR: - return simplify_logical (x, last); - - case ABS: - /* (abs (neg <foo>)) -> (abs <foo>) */ - if (GET_CODE (XEXP (x, 0)) == NEG) - SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); - - /* If the mode of the operand is VOIDmode (i.e. if it is ASM_OPERANDS), - do nothing. */ - if (GET_MODE (XEXP (x, 0)) == VOIDmode) - break; - - /* If operand is something known to be positive, ignore the ABS. */ - if (GET_CODE (XEXP (x, 0)) == FFS || GET_CODE (XEXP (x, 0)) == ABS - || ((GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - <= HOST_BITS_PER_WIDE_INT) - && ((nonzero_bits (XEXP (x, 0), GET_MODE (XEXP (x, 0))) - & ((HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - 1))) - == 0))) - return XEXP (x, 0); - - - /* If operand is known to be only -1 or 0, convert ABS to NEG. */ - if (num_sign_bit_copies (XEXP (x, 0), mode) == GET_MODE_BITSIZE (mode)) - return gen_rtx_combine (NEG, mode, XEXP (x, 0)); - - break; - - case FFS: - /* (ffs (*_extend <X>)) = (ffs <X>) */ - if (GET_CODE (XEXP (x, 0)) == SIGN_EXTEND - || GET_CODE (XEXP (x, 0)) == ZERO_EXTEND) - SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); - break; - - case FLOAT: - /* (float (sign_extend <X>)) = (float <X>). */ - if (GET_CODE (XEXP (x, 0)) == SIGN_EXTEND) - SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); - break; - - case ASHIFT: - case LSHIFTRT: - case ASHIFTRT: - case ROTATE: - case ROTATERT: - /* If this is a shift by a constant amount, simplify it. */ - if (GET_CODE (XEXP (x, 1)) == CONST_INT) - return simplify_shift_const (x, code, mode, XEXP (x, 0), - INTVAL (XEXP (x, 1))); - -#ifdef SHIFT_COUNT_TRUNCATED - else if (SHIFT_COUNT_TRUNCATED && GET_CODE (XEXP (x, 1)) != REG) - SUBST (XEXP (x, 1), - force_to_mode (XEXP (x, 1), GET_MODE (x), - ((HOST_WIDE_INT) 1 - << exact_log2 (GET_MODE_BITSIZE (GET_MODE (x)))) - - 1, - NULL_RTX, 0)); -#endif - - break; - - default: - break; - } - - return x; -} - -/* Simplify X, an IF_THEN_ELSE expression. Return the new expression. */ - -static rtx -simplify_if_then_else (x) - rtx x; -{ - enum machine_mode mode = GET_MODE (x); - rtx cond = XEXP (x, 0); - rtx true = XEXP (x, 1); - rtx false = XEXP (x, 2); - enum rtx_code true_code = GET_CODE (cond); - int comparison_p = GET_RTX_CLASS (true_code) == '<'; - rtx temp; - int i; - - /* Simplify storing of the truth value. */ - if (comparison_p && true == const_true_rtx && false == const0_rtx) - return gen_binary (true_code, mode, XEXP (cond, 0), XEXP (cond, 1)); - - /* Also when the truth value has to be reversed. */ - if (comparison_p && reversible_comparison_p (cond) - && true == const0_rtx && false == const_true_rtx) - return gen_binary (reverse_condition (true_code), - mode, XEXP (cond, 0), XEXP (cond, 1)); - - /* Sometimes we can simplify the arm of an IF_THEN_ELSE if a register used - in it is being compared against certain values. Get the true and false - comparisons and see if that says anything about the value of each arm. */ - - if (comparison_p && reversible_comparison_p (cond) - && GET_CODE (XEXP (cond, 0)) == REG) - { - HOST_WIDE_INT nzb; - rtx from = XEXP (cond, 0); - enum rtx_code false_code = reverse_condition (true_code); - rtx true_val = XEXP (cond, 1); - rtx false_val = true_val; - int swapped = 0; - - /* If FALSE_CODE is EQ, swap the codes and arms. */ - - if (false_code == EQ) - { - swapped = 1, true_code = EQ, false_code = NE; - temp = true, true = false, false = temp; - } - - /* If we are comparing against zero and the expression being tested has - only a single bit that might be nonzero, that is its value when it is - not equal to zero. Similarly if it is known to be -1 or 0. */ - - if (true_code == EQ && true_val == const0_rtx - && exact_log2 (nzb = nonzero_bits (from, GET_MODE (from))) >= 0) - false_code = EQ, false_val = GEN_INT (nzb); - else if (true_code == EQ && true_val == const0_rtx - && (num_sign_bit_copies (from, GET_MODE (from)) - == GET_MODE_BITSIZE (GET_MODE (from)))) - false_code = EQ, false_val = constm1_rtx; - - /* Now simplify an arm if we know the value of the register in the - branch and it is used in the arm. Be careful due to the potential - of locally-shared RTL. */ - - if (reg_mentioned_p (from, true)) - true = subst (known_cond (copy_rtx (true), true_code, from, true_val), - pc_rtx, pc_rtx, 0, 0); - if (reg_mentioned_p (from, false)) - false = subst (known_cond (copy_rtx (false), false_code, - from, false_val), - pc_rtx, pc_rtx, 0, 0); - - SUBST (XEXP (x, 1), swapped ? false : true); - SUBST (XEXP (x, 2), swapped ? true : false); - - true = XEXP (x, 1), false = XEXP (x, 2), true_code = GET_CODE (cond); - } - - /* If we have (if_then_else FOO (pc) (label_ref BAR)) and FOO can be - reversed, do so to avoid needing two sets of patterns for - subtract-and-branch insns. Similarly if we have a constant in the true - arm, the false arm is the same as the first operand of the comparison, or - the false arm is more complicated than the true arm. */ - - if (comparison_p && reversible_comparison_p (cond) - && (true == pc_rtx - || (CONSTANT_P (true) - && GET_CODE (false) != CONST_INT && false != pc_rtx) - || true == const0_rtx - || (GET_RTX_CLASS (GET_CODE (true)) == 'o' - && GET_RTX_CLASS (GET_CODE (false)) != 'o') - || (GET_CODE (true) == SUBREG - && GET_RTX_CLASS (GET_CODE (SUBREG_REG (true))) == 'o' - && GET_RTX_CLASS (GET_CODE (false)) != 'o') - || reg_mentioned_p (true, false) - || rtx_equal_p (false, XEXP (cond, 0)))) - { - true_code = reverse_condition (true_code); - SUBST (XEXP (x, 0), - gen_binary (true_code, GET_MODE (cond), XEXP (cond, 0), - XEXP (cond, 1))); - - SUBST (XEXP (x, 1), false); - SUBST (XEXP (x, 2), true); - - temp = true, true = false, false = temp, cond = XEXP (x, 0); - - /* It is possible that the conditional has been simplified out. */ - true_code = GET_CODE (cond); - comparison_p = GET_RTX_CLASS (true_code) == '<'; - } - - /* If the two arms are identical, we don't need the comparison. */ - - if (rtx_equal_p (true, false) && ! side_effects_p (cond)) - return true; - - /* Convert a == b ? b : a to "a". */ - if (true_code == EQ && ! side_effects_p (cond) - && rtx_equal_p (XEXP (cond, 0), false) - && rtx_equal_p (XEXP (cond, 1), true)) - return false; - else if (true_code == NE && ! side_effects_p (cond) - && rtx_equal_p (XEXP (cond, 0), true) - && rtx_equal_p (XEXP (cond, 1), false)) - return true; - - /* Look for cases where we have (abs x) or (neg (abs X)). */ - - if (GET_MODE_CLASS (mode) == MODE_INT - && GET_CODE (false) == NEG - && rtx_equal_p (true, XEXP (false, 0)) - && comparison_p - && rtx_equal_p (true, XEXP (cond, 0)) - && ! side_effects_p (true)) - switch (true_code) - { - case GT: - case GE: - return gen_unary (ABS, mode, mode, true); - case LT: - case LE: - return gen_unary (NEG, mode, mode, gen_unary (ABS, mode, mode, true)); - default: - break; - } - - /* Look for MIN or MAX. */ - - if ((! FLOAT_MODE_P (mode) || flag_fast_math) - && comparison_p - && rtx_equal_p (XEXP (cond, 0), true) - && rtx_equal_p (XEXP (cond, 1), false) - && ! side_effects_p (cond)) - switch (true_code) - { - case GE: - case GT: - return gen_binary (SMAX, mode, true, false); - case LE: - case LT: - return gen_binary (SMIN, mode, true, false); - case GEU: - case GTU: - return gen_binary (UMAX, mode, true, false); - case LEU: - case LTU: - return gen_binary (UMIN, mode, true, false); - default: - break; - } - - /* If we have (if_then_else COND (OP Z C1) Z) and OP is an identity when its - second operand is zero, this can be done as (OP Z (mult COND C2)) where - C2 = C1 * STORE_FLAG_VALUE. Similarly if OP has an outer ZERO_EXTEND or - SIGN_EXTEND as long as Z is already extended (so we don't destroy it). - We can do this kind of thing in some cases when STORE_FLAG_VALUE is - neither 1 or -1, but it isn't worth checking for. */ - - if ((STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1) - && comparison_p && mode != VOIDmode && ! side_effects_p (x)) - { - rtx t = make_compound_operation (true, SET); - rtx f = make_compound_operation (false, SET); - rtx cond_op0 = XEXP (cond, 0); - rtx cond_op1 = XEXP (cond, 1); - enum rtx_code op, extend_op = NIL; - enum machine_mode m = mode; - rtx z = 0, c1; - - if ((GET_CODE (t) == PLUS || GET_CODE (t) == MINUS - || GET_CODE (t) == IOR || GET_CODE (t) == XOR - || GET_CODE (t) == ASHIFT - || GET_CODE (t) == LSHIFTRT || GET_CODE (t) == ASHIFTRT) - && rtx_equal_p (XEXP (t, 0), f)) - c1 = XEXP (t, 1), op = GET_CODE (t), z = f; - - /* If an identity-zero op is commutative, check whether there - would be a match if we swapped the operands. */ - else if ((GET_CODE (t) == PLUS || GET_CODE (t) == IOR - || GET_CODE (t) == XOR) - && rtx_equal_p (XEXP (t, 1), f)) - c1 = XEXP (t, 0), op = GET_CODE (t), z = f; - else if (GET_CODE (t) == SIGN_EXTEND - && (GET_CODE (XEXP (t, 0)) == PLUS - || GET_CODE (XEXP (t, 0)) == MINUS - || GET_CODE (XEXP (t, 0)) == IOR - || GET_CODE (XEXP (t, 0)) == XOR - || GET_CODE (XEXP (t, 0)) == ASHIFT - || GET_CODE (XEXP (t, 0)) == LSHIFTRT - || GET_CODE (XEXP (t, 0)) == ASHIFTRT) - && GET_CODE (XEXP (XEXP (t, 0), 0)) == SUBREG - && subreg_lowpart_p (XEXP (XEXP (t, 0), 0)) - && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 0)), f) - && (num_sign_bit_copies (f, GET_MODE (f)) - > (GET_MODE_BITSIZE (mode) - - GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (t, 0), 0)))))) - { - c1 = XEXP (XEXP (t, 0), 1); z = f; op = GET_CODE (XEXP (t, 0)); - extend_op = SIGN_EXTEND; - m = GET_MODE (XEXP (t, 0)); - } - else if (GET_CODE (t) == SIGN_EXTEND - && (GET_CODE (XEXP (t, 0)) == PLUS - || GET_CODE (XEXP (t, 0)) == IOR - || GET_CODE (XEXP (t, 0)) == XOR) - && GET_CODE (XEXP (XEXP (t, 0), 1)) == SUBREG - && subreg_lowpart_p (XEXP (XEXP (t, 0), 1)) - && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 1)), f) - && (num_sign_bit_copies (f, GET_MODE (f)) - > (GET_MODE_BITSIZE (mode) - - GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (t, 0), 1)))))) - { - c1 = XEXP (XEXP (t, 0), 0); z = f; op = GET_CODE (XEXP (t, 0)); - extend_op = SIGN_EXTEND; - m = GET_MODE (XEXP (t, 0)); - } - else if (GET_CODE (t) == ZERO_EXTEND - && (GET_CODE (XEXP (t, 0)) == PLUS - || GET_CODE (XEXP (t, 0)) == MINUS - || GET_CODE (XEXP (t, 0)) == IOR - || GET_CODE (XEXP (t, 0)) == XOR - || GET_CODE (XEXP (t, 0)) == ASHIFT - || GET_CODE (XEXP (t, 0)) == LSHIFTRT - || GET_CODE (XEXP (t, 0)) == ASHIFTRT) - && GET_CODE (XEXP (XEXP (t, 0), 0)) == SUBREG - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && subreg_lowpart_p (XEXP (XEXP (t, 0), 0)) - && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 0)), f) - && ((nonzero_bits (f, GET_MODE (f)) - & ~ GET_MODE_MASK (GET_MODE (XEXP (XEXP (t, 0), 0)))) - == 0)) - { - c1 = XEXP (XEXP (t, 0), 1); z = f; op = GET_CODE (XEXP (t, 0)); - extend_op = ZERO_EXTEND; - m = GET_MODE (XEXP (t, 0)); - } - else if (GET_CODE (t) == ZERO_EXTEND - && (GET_CODE (XEXP (t, 0)) == PLUS - || GET_CODE (XEXP (t, 0)) == IOR - || GET_CODE (XEXP (t, 0)) == XOR) - && GET_CODE (XEXP (XEXP (t, 0), 1)) == SUBREG - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && subreg_lowpart_p (XEXP (XEXP (t, 0), 1)) - && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 1)), f) - && ((nonzero_bits (f, GET_MODE (f)) - & ~ GET_MODE_MASK (GET_MODE (XEXP (XEXP (t, 0), 1)))) - == 0)) - { - c1 = XEXP (XEXP (t, 0), 0); z = f; op = GET_CODE (XEXP (t, 0)); - extend_op = ZERO_EXTEND; - m = GET_MODE (XEXP (t, 0)); - } - - if (z) - { - temp = subst (gen_binary (true_code, m, cond_op0, cond_op1), - pc_rtx, pc_rtx, 0, 0); - temp = gen_binary (MULT, m, temp, - gen_binary (MULT, m, c1, const_true_rtx)); - temp = subst (temp, pc_rtx, pc_rtx, 0, 0); - temp = gen_binary (op, m, gen_lowpart_for_combine (m, z), temp); - - if (extend_op != NIL) - temp = gen_unary (extend_op, mode, m, temp); - - return temp; - } - } - - /* If we have (if_then_else (ne A 0) C1 0) and either A is known to be 0 or - 1 and C1 is a single bit or A is known to be 0 or -1 and C1 is the - negation of a single bit, we can convert this operation to a shift. We - can actually do this more generally, but it doesn't seem worth it. */ - - if (true_code == NE && XEXP (cond, 1) == const0_rtx - && false == const0_rtx && GET_CODE (true) == CONST_INT - && ((1 == nonzero_bits (XEXP (cond, 0), mode) - && (i = exact_log2 (INTVAL (true))) >= 0) - || ((num_sign_bit_copies (XEXP (cond, 0), mode) - == GET_MODE_BITSIZE (mode)) - && (i = exact_log2 (- INTVAL (true))) >= 0))) - return - simplify_shift_const (NULL_RTX, ASHIFT, mode, - gen_lowpart_for_combine (mode, XEXP (cond, 0)), i); - - return x; -} - -/* Simplify X, a SET expression. Return the new expression. */ - -static rtx -simplify_set (x) - rtx x; -{ - rtx src = SET_SRC (x); - rtx dest = SET_DEST (x); - enum machine_mode mode - = GET_MODE (src) != VOIDmode ? GET_MODE (src) : GET_MODE (dest); - rtx other_insn; - rtx *cc_use; - - /* (set (pc) (return)) gets written as (return). */ - if (GET_CODE (dest) == PC && GET_CODE (src) == RETURN) - return src; - - /* Now that we know for sure which bits of SRC we are using, see if we can - simplify the expression for the object knowing that we only need the - low-order bits. */ - - if (GET_MODE_CLASS (mode) == MODE_INT) - src = force_to_mode (src, mode, GET_MODE_MASK (mode), NULL_RTX, 0); - - /* If we are setting CC0 or if the source is a COMPARE, look for the use of - the comparison result and try to simplify it unless we already have used - undobuf.other_insn. */ - if ((GET_CODE (src) == COMPARE -#ifdef HAVE_cc0 - || dest == cc0_rtx -#endif - ) - && (cc_use = find_single_use (dest, subst_insn, &other_insn)) != 0 - && (undobuf.other_insn == 0 || other_insn == undobuf.other_insn) - && GET_RTX_CLASS (GET_CODE (*cc_use)) == '<' - && rtx_equal_p (XEXP (*cc_use, 0), dest)) - { - enum rtx_code old_code = GET_CODE (*cc_use); - enum rtx_code new_code; - rtx op0, op1; - int other_changed = 0; - enum machine_mode compare_mode = GET_MODE (dest); - - if (GET_CODE (src) == COMPARE) - op0 = XEXP (src, 0), op1 = XEXP (src, 1); - else - op0 = src, op1 = const0_rtx; - - /* Simplify our comparison, if possible. */ - new_code = simplify_comparison (old_code, &op0, &op1); - -#ifdef EXTRA_CC_MODES - /* If this machine has CC modes other than CCmode, check to see if we - need to use a different CC mode here. */ - compare_mode = SELECT_CC_MODE (new_code, op0, op1); -#endif /* EXTRA_CC_MODES */ - -#if !defined (HAVE_cc0) && defined (EXTRA_CC_MODES) - /* If the mode changed, we have to change SET_DEST, the mode in the - compare, and the mode in the place SET_DEST is used. If SET_DEST is - a hard register, just build new versions with the proper mode. If it - is a pseudo, we lose unless it is only time we set the pseudo, in - which case we can safely change its mode. */ - if (compare_mode != GET_MODE (dest)) - { - int regno = REGNO (dest); - rtx new_dest = gen_rtx_REG (compare_mode, regno); - - if (regno < FIRST_PSEUDO_REGISTER - || (REG_N_SETS (regno) == 1 && ! REG_USERVAR_P (dest))) - { - if (regno >= FIRST_PSEUDO_REGISTER) - SUBST (regno_reg_rtx[regno], new_dest); - - SUBST (SET_DEST (x), new_dest); - SUBST (XEXP (*cc_use, 0), new_dest); - other_changed = 1; - - dest = new_dest; - } - } -#endif - - /* If the code changed, we have to build a new comparison in - undobuf.other_insn. */ - if (new_code != old_code) - { - unsigned HOST_WIDE_INT mask; - - SUBST (*cc_use, gen_rtx_combine (new_code, GET_MODE (*cc_use), - dest, const0_rtx)); - - /* If the only change we made was to change an EQ into an NE or - vice versa, OP0 has only one bit that might be nonzero, and OP1 - is zero, check if changing the user of the condition code will - produce a valid insn. If it won't, we can keep the original code - in that insn by surrounding our operation with an XOR. */ - - if (((old_code == NE && new_code == EQ) - || (old_code == EQ && new_code == NE)) - && ! other_changed && op1 == const0_rtx - && GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT - && exact_log2 (mask = nonzero_bits (op0, GET_MODE (op0))) >= 0) - { - rtx pat = PATTERN (other_insn), note = 0; - - if ((recog_for_combine (&pat, other_insn, ¬e) < 0 - && ! check_asm_operands (pat))) - { - PUT_CODE (*cc_use, old_code); - other_insn = 0; - - op0 = gen_binary (XOR, GET_MODE (op0), op0, GEN_INT (mask)); - } - } - - other_changed = 1; - } - - if (other_changed) - undobuf.other_insn = other_insn; - -#ifdef HAVE_cc0 - /* If we are now comparing against zero, change our source if - needed. If we do not use cc0, we always have a COMPARE. */ - if (op1 == const0_rtx && dest == cc0_rtx) - { - SUBST (SET_SRC (x), op0); - src = op0; - } - else -#endif - - /* Otherwise, if we didn't previously have a COMPARE in the - correct mode, we need one. */ - if (GET_CODE (src) != COMPARE || GET_MODE (src) != compare_mode) - { - SUBST (SET_SRC (x), - gen_rtx_combine (COMPARE, compare_mode, op0, op1)); - src = SET_SRC (x); - } - else - { - /* Otherwise, update the COMPARE if needed. */ - SUBST (XEXP (src, 0), op0); - SUBST (XEXP (src, 1), op1); - } - } - else - { - /* Get SET_SRC in a form where we have placed back any - compound expressions. Then do the checks below. */ - src = make_compound_operation (src, SET); - SUBST (SET_SRC (x), src); - } - - /* If we have (set x (subreg:m1 (op:m2 ...) 0)) with OP being some operation, - and X being a REG or (subreg (reg)), we may be able to convert this to - (set (subreg:m2 x) (op)). - - We can always do this if M1 is narrower than M2 because that means that - we only care about the low bits of the result. - - However, on machines without WORD_REGISTER_OPERATIONS defined, we cannot - perform a narrower operation than requested since the high-order bits will - be undefined. On machine where it is defined, this transformation is safe - as long as M1 and M2 have the same number of words. */ - - if (GET_CODE (src) == SUBREG && subreg_lowpart_p (src) - && GET_RTX_CLASS (GET_CODE (SUBREG_REG (src))) != 'o' - && (((GET_MODE_SIZE (GET_MODE (src)) + (UNITS_PER_WORD - 1)) - / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (src))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)) -#ifndef WORD_REGISTER_OPERATIONS - && (GET_MODE_SIZE (GET_MODE (src)) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))) -#endif -#ifdef CLASS_CANNOT_CHANGE_SIZE - && ! (GET_CODE (dest) == REG && REGNO (dest) < FIRST_PSEUDO_REGISTER - && (TEST_HARD_REG_BIT - (reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE], - REGNO (dest))) - && (GET_MODE_SIZE (GET_MODE (src)) - != GET_MODE_SIZE (GET_MODE (SUBREG_REG (src))))) -#endif - && (GET_CODE (dest) == REG - || (GET_CODE (dest) == SUBREG - && GET_CODE (SUBREG_REG (dest)) == REG))) - { - SUBST (SET_DEST (x), - gen_lowpart_for_combine (GET_MODE (SUBREG_REG (src)), - dest)); - SUBST (SET_SRC (x), SUBREG_REG (src)); - - src = SET_SRC (x), dest = SET_DEST (x); - } - -#ifdef LOAD_EXTEND_OP - /* If we have (set FOO (subreg:M (mem:N BAR) 0)) with M wider than N, this - would require a paradoxical subreg. Replace the subreg with a - zero_extend to avoid the reload that would otherwise be required. */ - - if (GET_CODE (src) == SUBREG && subreg_lowpart_p (src) - && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src))) != NIL - && SUBREG_WORD (src) == 0 - && (GET_MODE_SIZE (GET_MODE (src)) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))) - && GET_CODE (SUBREG_REG (src)) == MEM) - { - SUBST (SET_SRC (x), - gen_rtx_combine (LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src))), - GET_MODE (src), XEXP (src, 0))); - - src = SET_SRC (x); - } -#endif - - /* If we don't have a conditional move, SET_SRC is an IF_THEN_ELSE, and we - are comparing an item known to be 0 or -1 against 0, use a logical - operation instead. Check for one of the arms being an IOR of the other - arm with some value. We compute three terms to be IOR'ed together. In - practice, at most two will be nonzero. Then we do the IOR's. */ - - if (GET_CODE (dest) != PC - && GET_CODE (src) == IF_THEN_ELSE - && GET_MODE_CLASS (GET_MODE (src)) == MODE_INT - && (GET_CODE (XEXP (src, 0)) == EQ || GET_CODE (XEXP (src, 0)) == NE) - && XEXP (XEXP (src, 0), 1) == const0_rtx - && GET_MODE (src) == GET_MODE (XEXP (XEXP (src, 0), 0)) -#ifdef HAVE_conditional_move - && ! can_conditionally_move_p (GET_MODE (src)) -#endif - && (num_sign_bit_copies (XEXP (XEXP (src, 0), 0), - GET_MODE (XEXP (XEXP (src, 0), 0))) - == GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (src, 0), 0)))) - && ! side_effects_p (src)) - { - rtx true = (GET_CODE (XEXP (src, 0)) == NE - ? XEXP (src, 1) : XEXP (src, 2)); - rtx false = (GET_CODE (XEXP (src, 0)) == NE - ? XEXP (src, 2) : XEXP (src, 1)); - rtx term1 = const0_rtx, term2, term3; - - if (GET_CODE (true) == IOR && rtx_equal_p (XEXP (true, 0), false)) - term1 = false, true = XEXP (true, 1), false = const0_rtx; - else if (GET_CODE (true) == IOR - && rtx_equal_p (XEXP (true, 1), false)) - term1 = false, true = XEXP (true, 0), false = const0_rtx; - else if (GET_CODE (false) == IOR - && rtx_equal_p (XEXP (false, 0), true)) - term1 = true, false = XEXP (false, 1), true = const0_rtx; - else if (GET_CODE (false) == IOR - && rtx_equal_p (XEXP (false, 1), true)) - term1 = true, false = XEXP (false, 0), true = const0_rtx; - - term2 = gen_binary (AND, GET_MODE (src), XEXP (XEXP (src, 0), 0), true); - term3 = gen_binary (AND, GET_MODE (src), - gen_unary (NOT, GET_MODE (src), GET_MODE (src), - XEXP (XEXP (src, 0), 0)), - false); - - SUBST (SET_SRC (x), - gen_binary (IOR, GET_MODE (src), - gen_binary (IOR, GET_MODE (src), term1, term2), - term3)); - - src = SET_SRC (x); - } - - /* If either SRC or DEST is a CLOBBER of (const_int 0), make this - whole thing fail. */ - if (GET_CODE (src) == CLOBBER && XEXP (src, 0) == const0_rtx) - return src; - else if (GET_CODE (dest) == CLOBBER && XEXP (dest, 0) == const0_rtx) - return dest; - else - /* Convert this into a field assignment operation, if possible. */ - return make_field_assignment (x); -} - -/* Simplify, X, and AND, IOR, or XOR operation, and return the simplified - result. LAST is nonzero if this is the last retry. */ - -static rtx -simplify_logical (x, last) - rtx x; - int last; -{ - enum machine_mode mode = GET_MODE (x); - rtx op0 = XEXP (x, 0); - rtx op1 = XEXP (x, 1); - - switch (GET_CODE (x)) - { - case AND: - /* Convert (A ^ B) & A to A & (~ B) since the latter is often a single - insn (and may simplify more). */ - if (GET_CODE (op0) == XOR - && rtx_equal_p (XEXP (op0, 0), op1) - && ! side_effects_p (op1)) - x = gen_binary (AND, mode, - gen_unary (NOT, mode, mode, XEXP (op0, 1)), op1); - - if (GET_CODE (op0) == XOR - && rtx_equal_p (XEXP (op0, 1), op1) - && ! side_effects_p (op1)) - x = gen_binary (AND, mode, - gen_unary (NOT, mode, mode, XEXP (op0, 0)), op1); - - /* Similarly for (~ (A ^ B)) & A. */ - if (GET_CODE (op0) == NOT - && GET_CODE (XEXP (op0, 0)) == XOR - && rtx_equal_p (XEXP (XEXP (op0, 0), 0), op1) - && ! side_effects_p (op1)) - x = gen_binary (AND, mode, XEXP (XEXP (op0, 0), 1), op1); - - if (GET_CODE (op0) == NOT - && GET_CODE (XEXP (op0, 0)) == XOR - && rtx_equal_p (XEXP (XEXP (op0, 0), 1), op1) - && ! side_effects_p (op1)) - x = gen_binary (AND, mode, XEXP (XEXP (op0, 0), 0), op1); - - if (GET_CODE (op1) == CONST_INT) - { - x = simplify_and_const_int (x, mode, op0, INTVAL (op1)); - - /* If we have (ior (and (X C1) C2)) and the next restart would be - the last, simplify this by making C1 as small as possible - and then exit. */ - if (last - && GET_CODE (x) == IOR && GET_CODE (op0) == AND - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && GET_CODE (op1) == CONST_INT) - return gen_binary (IOR, mode, - gen_binary (AND, mode, XEXP (op0, 0), - GEN_INT (INTVAL (XEXP (op0, 1)) - & ~ INTVAL (op1))), op1); - - if (GET_CODE (x) != AND) - return x; - - if (GET_RTX_CLASS (GET_CODE (x)) == 'c' - || GET_RTX_CLASS (GET_CODE (x)) == '2') - op0 = XEXP (x, 0), op1 = XEXP (x, 1); - } - - /* Convert (A | B) & A to A. */ - if (GET_CODE (op0) == IOR - && (rtx_equal_p (XEXP (op0, 0), op1) - || rtx_equal_p (XEXP (op0, 1), op1)) - && ! side_effects_p (XEXP (op0, 0)) - && ! side_effects_p (XEXP (op0, 1))) - return op1; - - /* In the following group of tests (and those in case IOR below), - we start with some combination of logical operations and apply - the distributive law followed by the inverse distributive law. - Most of the time, this results in no change. However, if some of - the operands are the same or inverses of each other, simplifications - will result. - - For example, (and (ior A B) (not B)) can occur as the result of - expanding a bit field assignment. When we apply the distributive - law to this, we get (ior (and (A (not B))) (and (B (not B)))), - which then simplifies to (and (A (not B))). - - If we have (and (ior A B) C), apply the distributive law and then - the inverse distributive law to see if things simplify. */ - - if (GET_CODE (op0) == IOR || GET_CODE (op0) == XOR) - { - x = apply_distributive_law - (gen_binary (GET_CODE (op0), mode, - gen_binary (AND, mode, XEXP (op0, 0), op1), - gen_binary (AND, mode, XEXP (op0, 1), op1))); - if (GET_CODE (x) != AND) - return x; - } - - if (GET_CODE (op1) == IOR || GET_CODE (op1) == XOR) - return apply_distributive_law - (gen_binary (GET_CODE (op1), mode, - gen_binary (AND, mode, XEXP (op1, 0), op0), - gen_binary (AND, mode, XEXP (op1, 1), op0))); - - /* Similarly, taking advantage of the fact that - (and (not A) (xor B C)) == (xor (ior A B) (ior A C)) */ - - if (GET_CODE (op0) == NOT && GET_CODE (op1) == XOR) - return apply_distributive_law - (gen_binary (XOR, mode, - gen_binary (IOR, mode, XEXP (op0, 0), XEXP (op1, 0)), - gen_binary (IOR, mode, XEXP (op0, 0), XEXP (op1, 1)))); - - else if (GET_CODE (op1) == NOT && GET_CODE (op0) == XOR) - return apply_distributive_law - (gen_binary (XOR, mode, - gen_binary (IOR, mode, XEXP (op1, 0), XEXP (op0, 0)), - gen_binary (IOR, mode, XEXP (op1, 0), XEXP (op0, 1)))); - break; - - case IOR: - /* (ior A C) is C if all bits of A that might be nonzero are on in C. */ - if (GET_CODE (op1) == CONST_INT - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (op0, mode) & ~ INTVAL (op1)) == 0) - return op1; - - /* Convert (A & B) | A to A. */ - if (GET_CODE (op0) == AND - && (rtx_equal_p (XEXP (op0, 0), op1) - || rtx_equal_p (XEXP (op0, 1), op1)) - && ! side_effects_p (XEXP (op0, 0)) - && ! side_effects_p (XEXP (op0, 1))) - return op1; - - /* If we have (ior (and A B) C), apply the distributive law and then - the inverse distributive law to see if things simplify. */ - - if (GET_CODE (op0) == AND) - { - x = apply_distributive_law - (gen_binary (AND, mode, - gen_binary (IOR, mode, XEXP (op0, 0), op1), - gen_binary (IOR, mode, XEXP (op0, 1), op1))); - - if (GET_CODE (x) != IOR) - return x; - } - - if (GET_CODE (op1) == AND) - { - x = apply_distributive_law - (gen_binary (AND, mode, - gen_binary (IOR, mode, XEXP (op1, 0), op0), - gen_binary (IOR, mode, XEXP (op1, 1), op0))); - - if (GET_CODE (x) != IOR) - return x; - } - - /* Convert (ior (ashift A CX) (lshiftrt A CY)) where CX+CY equals the - mode size to (rotate A CX). */ - - if (((GET_CODE (op0) == ASHIFT && GET_CODE (op1) == LSHIFTRT) - || (GET_CODE (op1) == ASHIFT && GET_CODE (op0) == LSHIFTRT)) - && rtx_equal_p (XEXP (op0, 0), XEXP (op1, 0)) - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && GET_CODE (XEXP (op1, 1)) == CONST_INT - && (INTVAL (XEXP (op0, 1)) + INTVAL (XEXP (op1, 1)) - == GET_MODE_BITSIZE (mode))) - return gen_rtx_ROTATE (mode, XEXP (op0, 0), - (GET_CODE (op0) == ASHIFT - ? XEXP (op0, 1) : XEXP (op1, 1))); - - /* If OP0 is (ashiftrt (plus ...) C), it might actually be - a (sign_extend (plus ...)). If so, OP1 is a CONST_INT, and the PLUS - does not affect any of the bits in OP1, it can really be done - as a PLUS and we can associate. We do this by seeing if OP1 - can be safely shifted left C bits. */ - if (GET_CODE (op1) == CONST_INT && GET_CODE (op0) == ASHIFTRT - && GET_CODE (XEXP (op0, 0)) == PLUS - && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) < HOST_BITS_PER_WIDE_INT) - { - int count = INTVAL (XEXP (op0, 1)); - HOST_WIDE_INT mask = INTVAL (op1) << count; - - if (mask >> count == INTVAL (op1) - && (mask & nonzero_bits (XEXP (op0, 0), mode)) == 0) - { - SUBST (XEXP (XEXP (op0, 0), 1), - GEN_INT (INTVAL (XEXP (XEXP (op0, 0), 1)) | mask)); - return op0; - } - } - break; - - case XOR: - /* Convert (XOR (NOT x) (NOT y)) to (XOR x y). - Also convert (XOR (NOT x) y) to (NOT (XOR x y)), similarly for - (NOT y). */ - { - int num_negated = 0; - - if (GET_CODE (op0) == NOT) - num_negated++, op0 = XEXP (op0, 0); - if (GET_CODE (op1) == NOT) - num_negated++, op1 = XEXP (op1, 0); - - if (num_negated == 2) - { - SUBST (XEXP (x, 0), op0); - SUBST (XEXP (x, 1), op1); - } - else if (num_negated == 1) - return gen_unary (NOT, mode, mode, gen_binary (XOR, mode, op0, op1)); - } - - /* Convert (xor (and A B) B) to (and (not A) B). The latter may - correspond to a machine insn or result in further simplifications - if B is a constant. */ - - if (GET_CODE (op0) == AND - && rtx_equal_p (XEXP (op0, 1), op1) - && ! side_effects_p (op1)) - return gen_binary (AND, mode, - gen_unary (NOT, mode, mode, XEXP (op0, 0)), - op1); - - else if (GET_CODE (op0) == AND - && rtx_equal_p (XEXP (op0, 0), op1) - && ! side_effects_p (op1)) - return gen_binary (AND, mode, - gen_unary (NOT, mode, mode, XEXP (op0, 1)), - op1); - - /* (xor (comparison foo bar) (const_int 1)) can become the reversed - comparison if STORE_FLAG_VALUE is 1. */ - if (STORE_FLAG_VALUE == 1 - && op1 == const1_rtx - && GET_RTX_CLASS (GET_CODE (op0)) == '<' - && reversible_comparison_p (op0)) - return gen_rtx_combine (reverse_condition (GET_CODE (op0)), - mode, XEXP (op0, 0), XEXP (op0, 1)); - - /* (lshiftrt foo C) where C is the number of bits in FOO minus 1 - is (lt foo (const_int 0)), so we can perform the above - simplification if STORE_FLAG_VALUE is 1. */ - - if (STORE_FLAG_VALUE == 1 - && op1 == const1_rtx - && GET_CODE (op0) == LSHIFTRT - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) == GET_MODE_BITSIZE (mode) - 1) - return gen_rtx_combine (GE, mode, XEXP (op0, 0), const0_rtx); - - /* (xor (comparison foo bar) (const_int sign-bit)) - when STORE_FLAG_VALUE is the sign bit. */ - if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && ((STORE_FLAG_VALUE & GET_MODE_MASK (mode)) - == (unsigned HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (mode) - 1)) - && op1 == const_true_rtx - && GET_RTX_CLASS (GET_CODE (op0)) == '<' - && reversible_comparison_p (op0)) - return gen_rtx_combine (reverse_condition (GET_CODE (op0)), - mode, XEXP (op0, 0), XEXP (op0, 1)); - break; - - default: - abort (); - } - - return x; -} - -/* We consider ZERO_EXTRACT, SIGN_EXTRACT, and SIGN_EXTEND as "compound - operations" because they can be replaced with two more basic operations. - ZERO_EXTEND is also considered "compound" because it can be replaced with - an AND operation, which is simpler, though only one operation. - - The function expand_compound_operation is called with an rtx expression - and will convert it to the appropriate shifts and AND operations, - simplifying at each stage. - - The function make_compound_operation is called to convert an expression - consisting of shifts and ANDs into the equivalent compound expression. - It is the inverse of this function, loosely speaking. */ - -static rtx -expand_compound_operation (x) - rtx x; -{ - int pos = 0, len; - int unsignedp = 0; - int modewidth; - rtx tem; - - switch (GET_CODE (x)) - { - case ZERO_EXTEND: - unsignedp = 1; - case SIGN_EXTEND: - /* We can't necessarily use a const_int for a multiword mode; - it depends on implicitly extending the value. - Since we don't know the right way to extend it, - we can't tell whether the implicit way is right. - - Even for a mode that is no wider than a const_int, - we can't win, because we need to sign extend one of its bits through - the rest of it, and we don't know which bit. */ - if (GET_CODE (XEXP (x, 0)) == CONST_INT) - return x; - - /* Return if (subreg:MODE FROM 0) is not a safe replacement for - (zero_extend:MODE FROM) or (sign_extend:MODE FROM). It is for any MEM - because (SUBREG (MEM...)) is guaranteed to cause the MEM to be - reloaded. If not for that, MEM's would very rarely be safe. - - Reject MODEs bigger than a word, because we might not be able - to reference a two-register group starting with an arbitrary register - (and currently gen_lowpart might crash for a SUBREG). */ - - if (GET_MODE_SIZE (GET_MODE (XEXP (x, 0))) > UNITS_PER_WORD) - return x; - - len = GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))); - /* If the inner object has VOIDmode (the only way this can happen - is if it is a ASM_OPERANDS), we can't do anything since we don't - know how much masking to do. */ - if (len == 0) - return x; - - break; - - case ZERO_EXTRACT: - unsignedp = 1; - case SIGN_EXTRACT: - /* If the operand is a CLOBBER, just return it. */ - if (GET_CODE (XEXP (x, 0)) == CLOBBER) - return XEXP (x, 0); - - if (GET_CODE (XEXP (x, 1)) != CONST_INT - || GET_CODE (XEXP (x, 2)) != CONST_INT - || GET_MODE (XEXP (x, 0)) == VOIDmode) - return x; - - len = INTVAL (XEXP (x, 1)); - pos = INTVAL (XEXP (x, 2)); - - /* If this goes outside the object being extracted, replace the object - with a (use (mem ...)) construct that only combine understands - and is used only for this purpose. */ - if (len + pos > GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))) - SUBST (XEXP (x, 0), gen_rtx_USE (GET_MODE (x), XEXP (x, 0))); - - if (BITS_BIG_ENDIAN) - pos = GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - len - pos; - - break; - - default: - return x; - } - - /* We can optimize some special cases of ZERO_EXTEND. */ - if (GET_CODE (x) == ZERO_EXTEND) - { - /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI if we - know that the last value didn't have any inappropriate bits - set. */ - if (GET_CODE (XEXP (x, 0)) == TRUNCATE - && GET_MODE (XEXP (XEXP (x, 0), 0)) == GET_MODE (x) - && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (XEXP (XEXP (x, 0), 0), GET_MODE (x)) - & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) == 0) - return XEXP (XEXP (x, 0), 0); - - /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */ - if (GET_CODE (XEXP (x, 0)) == SUBREG - && GET_MODE (SUBREG_REG (XEXP (x, 0))) == GET_MODE (x) - && subreg_lowpart_p (XEXP (x, 0)) - && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (SUBREG_REG (XEXP (x, 0)), GET_MODE (x)) - & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) == 0) - return SUBREG_REG (XEXP (x, 0)); - - /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI when foo - is a comparison and STORE_FLAG_VALUE permits. This is like - the first case, but it works even when GET_MODE (x) is larger - than HOST_WIDE_INT. */ - if (GET_CODE (XEXP (x, 0)) == TRUNCATE - && GET_MODE (XEXP (XEXP (x, 0), 0)) == GET_MODE (x) - && GET_RTX_CLASS (GET_CODE (XEXP (XEXP (x, 0), 0))) == '<' - && (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - <= HOST_BITS_PER_WIDE_INT) - && ((HOST_WIDE_INT) STORE_FLAG_VALUE - & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) == 0) - return XEXP (XEXP (x, 0), 0); - - /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */ - if (GET_CODE (XEXP (x, 0)) == SUBREG - && GET_MODE (SUBREG_REG (XEXP (x, 0))) == GET_MODE (x) - && subreg_lowpart_p (XEXP (x, 0)) - && GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 0)))) == '<' - && (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - <= HOST_BITS_PER_WIDE_INT) - && ((HOST_WIDE_INT) STORE_FLAG_VALUE - & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) == 0) - return SUBREG_REG (XEXP (x, 0)); - - /* If sign extension is cheaper than zero extension, then use it - if we know that no extraneous bits are set, and that the high - bit is not set. */ - if (flag_expensive_optimizations - && ((GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT - && ((nonzero_bits (XEXP (x, 0), GET_MODE (x)) - & ~ (((unsigned HOST_WIDE_INT) - GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) - >> 1)) - == 0)) - || (GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == '<' - && (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - <= HOST_BITS_PER_WIDE_INT) - && (((HOST_WIDE_INT) STORE_FLAG_VALUE - & ~ (((unsigned HOST_WIDE_INT) - GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) - >> 1)) - == 0)))) - { - rtx temp = gen_rtx_SIGN_EXTEND (GET_MODE (x), XEXP (x, 0)); - - if (rtx_cost (temp, SET) < rtx_cost (x, SET)) - return expand_compound_operation (temp); - } - } - - /* If we reach here, we want to return a pair of shifts. The inner - shift is a left shift of BITSIZE - POS - LEN bits. The outer - shift is a right shift of BITSIZE - LEN bits. It is arithmetic or - logical depending on the value of UNSIGNEDP. - - If this was a ZERO_EXTEND or ZERO_EXTRACT, this pair of shifts will be - converted into an AND of a shift. - - We must check for the case where the left shift would have a negative - count. This can happen in a case like (x >> 31) & 255 on machines - that can't shift by a constant. On those machines, we would first - combine the shift with the AND to produce a variable-position - extraction. Then the constant of 31 would be substituted in to produce - a such a position. */ - - modewidth = GET_MODE_BITSIZE (GET_MODE (x)); - if (modewidth >= pos - len) - tem = simplify_shift_const (NULL_RTX, unsignedp ? LSHIFTRT : ASHIFTRT, - GET_MODE (x), - simplify_shift_const (NULL_RTX, ASHIFT, - GET_MODE (x), - XEXP (x, 0), - modewidth - pos - len), - modewidth - len); - - else if (unsignedp && len < HOST_BITS_PER_WIDE_INT) - tem = simplify_and_const_int (NULL_RTX, GET_MODE (x), - simplify_shift_const (NULL_RTX, LSHIFTRT, - GET_MODE (x), - XEXP (x, 0), pos), - ((HOST_WIDE_INT) 1 << len) - 1); - else - /* Any other cases we can't handle. */ - return x; - - - /* If we couldn't do this for some reason, return the original - expression. */ - if (GET_CODE (tem) == CLOBBER) - return x; - - return tem; -} - -/* X is a SET which contains an assignment of one object into - a part of another (such as a bit-field assignment, STRICT_LOW_PART, - or certain SUBREGS). If possible, convert it into a series of - logical operations. - - We half-heartedly support variable positions, but do not at all - support variable lengths. */ - -static rtx -expand_field_assignment (x) - rtx x; -{ - rtx inner; - rtx pos; /* Always counts from low bit. */ - int len; - rtx mask; - enum machine_mode compute_mode; - - /* Loop until we find something we can't simplify. */ - while (1) - { - if (GET_CODE (SET_DEST (x)) == STRICT_LOW_PART - && GET_CODE (XEXP (SET_DEST (x), 0)) == SUBREG) - { - inner = SUBREG_REG (XEXP (SET_DEST (x), 0)); - len = GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x), 0))); - pos = GEN_INT (BITS_PER_WORD * SUBREG_WORD (XEXP (SET_DEST (x), 0))); - } - else if (GET_CODE (SET_DEST (x)) == ZERO_EXTRACT - && GET_CODE (XEXP (SET_DEST (x), 1)) == CONST_INT) - { - inner = XEXP (SET_DEST (x), 0); - len = INTVAL (XEXP (SET_DEST (x), 1)); - pos = XEXP (SET_DEST (x), 2); - - /* If the position is constant and spans the width of INNER, - surround INNER with a USE to indicate this. */ - if (GET_CODE (pos) == CONST_INT - && INTVAL (pos) + len > GET_MODE_BITSIZE (GET_MODE (inner))) - inner = gen_rtx_USE (GET_MODE (SET_DEST (x)), inner); - - if (BITS_BIG_ENDIAN) - { - if (GET_CODE (pos) == CONST_INT) - pos = GEN_INT (GET_MODE_BITSIZE (GET_MODE (inner)) - len - - INTVAL (pos)); - else if (GET_CODE (pos) == MINUS - && GET_CODE (XEXP (pos, 1)) == CONST_INT - && (INTVAL (XEXP (pos, 1)) - == GET_MODE_BITSIZE (GET_MODE (inner)) - len)) - /* If position is ADJUST - X, new position is X. */ - pos = XEXP (pos, 0); - else - pos = gen_binary (MINUS, GET_MODE (pos), - GEN_INT (GET_MODE_BITSIZE (GET_MODE (inner)) - - len), - pos); - } - } - - /* A SUBREG between two modes that occupy the same numbers of words - can be done by moving the SUBREG to the source. */ - else if (GET_CODE (SET_DEST (x)) == SUBREG - && (((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD))) - { - x = gen_rtx_SET (VOIDmode, SUBREG_REG (SET_DEST (x)), - gen_lowpart_for_combine (GET_MODE (SUBREG_REG (SET_DEST (x))), - SET_SRC (x))); - continue; - } - else - break; - - while (GET_CODE (inner) == SUBREG && subreg_lowpart_p (inner)) - inner = SUBREG_REG (inner); - - compute_mode = GET_MODE (inner); - - /* Don't attempt bitwise arithmetic on non-integral modes. */ - if (! INTEGRAL_MODE_P (compute_mode)) - { - enum machine_mode imode; - - /* Something is probably seriously wrong if this matches. */ - if (! FLOAT_MODE_P (compute_mode)) - break; - - /* Try to find an integral mode to pun with. */ - imode = mode_for_size (GET_MODE_BITSIZE (compute_mode), MODE_INT, 0); - if (imode == BLKmode) - break; - - compute_mode = imode; - inner = gen_lowpart_for_combine (imode, inner); - } - - /* Compute a mask of LEN bits, if we can do this on the host machine. */ - if (len < HOST_BITS_PER_WIDE_INT) - mask = GEN_INT (((HOST_WIDE_INT) 1 << len) - 1); - else - break; - - /* Now compute the equivalent expression. Make a copy of INNER - for the SET_DEST in case it is a MEM into which we will substitute; - we don't want shared RTL in that case. */ - x = gen_rtx_SET (VOIDmode, copy_rtx (inner), - gen_binary (IOR, compute_mode, - gen_binary (AND, compute_mode, - gen_unary (NOT, compute_mode, - compute_mode, - gen_binary (ASHIFT, - compute_mode, - mask, pos)), - inner), - gen_binary (ASHIFT, compute_mode, - gen_binary (AND, compute_mode, - gen_lowpart_for_combine - (compute_mode, - SET_SRC (x)), - mask), - pos))); - } - - return x; -} - -/* Return an RTX for a reference to LEN bits of INNER. If POS_RTX is nonzero, - it is an RTX that represents a variable starting position; otherwise, - POS is the (constant) starting bit position (counted from the LSB). - - INNER may be a USE. This will occur when we started with a bitfield - that went outside the boundary of the object in memory, which is - allowed on most machines. To isolate this case, we produce a USE - whose mode is wide enough and surround the MEM with it. The only - code that understands the USE is this routine. If it is not removed, - it will cause the resulting insn not to match. - - UNSIGNEDP is non-zero for an unsigned reference and zero for a - signed reference. - - IN_DEST is non-zero if this is a reference in the destination of a - SET. This is used when a ZERO_ or SIGN_EXTRACT isn't needed. If non-zero, - a STRICT_LOW_PART will be used, if zero, ZERO_EXTEND or SIGN_EXTEND will - be used. - - IN_COMPARE is non-zero if we are in a COMPARE. This means that a - ZERO_EXTRACT should be built even for bits starting at bit 0. - - MODE is the desired mode of the result (if IN_DEST == 0). - - The result is an RTX for the extraction or NULL_RTX if the target - can't handle it. */ - -static rtx -make_extraction (mode, inner, pos, pos_rtx, len, - unsignedp, in_dest, in_compare) - enum machine_mode mode; - rtx inner; - int pos; - rtx pos_rtx; - int len; - int unsignedp; - int in_dest, in_compare; -{ - /* This mode describes the size of the storage area - to fetch the overall value from. Within that, we - ignore the POS lowest bits, etc. */ - enum machine_mode is_mode = GET_MODE (inner); - enum machine_mode inner_mode; - enum machine_mode wanted_inner_mode = byte_mode; - enum machine_mode wanted_inner_reg_mode = word_mode; - enum machine_mode pos_mode = word_mode; - enum machine_mode extraction_mode = word_mode; - enum machine_mode tmode = mode_for_size (len, MODE_INT, 1); - int spans_byte = 0; - rtx new = 0; - rtx orig_pos_rtx = pos_rtx; - int orig_pos; - - /* Get some information about INNER and get the innermost object. */ - if (GET_CODE (inner) == USE) - /* (use:SI (mem:QI foo)) stands for (mem:SI foo). */ - /* We don't need to adjust the position because we set up the USE - to pretend that it was a full-word object. */ - spans_byte = 1, inner = XEXP (inner, 0); - else if (GET_CODE (inner) == SUBREG && subreg_lowpart_p (inner)) - { - /* If going from (subreg:SI (mem:QI ...)) to (mem:QI ...), - consider just the QI as the memory to extract from. - The subreg adds or removes high bits; its mode is - irrelevant to the meaning of this extraction, - since POS and LEN count from the lsb. */ - if (GET_CODE (SUBREG_REG (inner)) == MEM) - is_mode = GET_MODE (SUBREG_REG (inner)); - inner = SUBREG_REG (inner); - } - - inner_mode = GET_MODE (inner); - - if (pos_rtx && GET_CODE (pos_rtx) == CONST_INT) - pos = INTVAL (pos_rtx), pos_rtx = 0; - - /* See if this can be done without an extraction. We never can if the - width of the field is not the same as that of some integer mode. For - registers, we can only avoid the extraction if the position is at the - low-order bit and this is either not in the destination or we have the - appropriate STRICT_LOW_PART operation available. - - For MEM, we can avoid an extract if the field starts on an appropriate - boundary and we can change the mode of the memory reference. However, - we cannot directly access the MEM if we have a USE and the underlying - MEM is not TMODE. This combination means that MEM was being used in a - context where bits outside its mode were being referenced; that is only - valid in bit-field insns. */ - - if (tmode != BLKmode - && ! (spans_byte && inner_mode != tmode) - && ((pos_rtx == 0 && (pos % BITS_PER_WORD) == 0 - && GET_CODE (inner) != MEM - && (! in_dest - || (GET_CODE (inner) == REG - && (movstrict_optab->handlers[(int) tmode].insn_code - != CODE_FOR_nothing)))) - || (GET_CODE (inner) == MEM && pos_rtx == 0 - && (pos - % (STRICT_ALIGNMENT ? GET_MODE_ALIGNMENT (tmode) - : BITS_PER_UNIT)) == 0 - /* We can't do this if we are widening INNER_MODE (it - may not be aligned, for one thing). */ - && GET_MODE_BITSIZE (inner_mode) >= GET_MODE_BITSIZE (tmode) - && (inner_mode == tmode - || (! mode_dependent_address_p (XEXP (inner, 0)) - && ! MEM_VOLATILE_P (inner)))))) - { - /* If INNER is a MEM, make a new MEM that encompasses just the desired - field. If the original and current mode are the same, we need not - adjust the offset. Otherwise, we do if bytes big endian. - - If INNER is not a MEM, get a piece consisting of just the field - of interest (in this case POS % BITS_PER_WORD must be 0). */ - - if (GET_CODE (inner) == MEM) - { - int offset; - /* POS counts from lsb, but make OFFSET count in memory order. */ - if (BYTES_BIG_ENDIAN) - offset = (GET_MODE_BITSIZE (is_mode) - len - pos) / BITS_PER_UNIT; - else - offset = pos / BITS_PER_UNIT; - - new = gen_rtx_MEM (tmode, plus_constant (XEXP (inner, 0), offset)); - RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (inner); - MEM_COPY_ATTRIBUTES (new, inner); - } - else if (GET_CODE (inner) == REG) - { - /* We can't call gen_lowpart_for_combine here since we always want - a SUBREG and it would sometimes return a new hard register. */ - if (tmode != inner_mode) - new = gen_rtx_SUBREG (tmode, inner, - (WORDS_BIG_ENDIAN - && GET_MODE_SIZE (inner_mode) > UNITS_PER_WORD - ? (((GET_MODE_SIZE (inner_mode) - - GET_MODE_SIZE (tmode)) - / UNITS_PER_WORD) - - pos / BITS_PER_WORD) - : pos / BITS_PER_WORD)); - else - new = inner; - } - else - new = force_to_mode (inner, tmode, - len >= HOST_BITS_PER_WIDE_INT - ? GET_MODE_MASK (tmode) - : ((HOST_WIDE_INT) 1 << len) - 1, - NULL_RTX, 0); - - /* If this extraction is going into the destination of a SET, - make a STRICT_LOW_PART unless we made a MEM. */ - - if (in_dest) - return (GET_CODE (new) == MEM ? new - : (GET_CODE (new) != SUBREG - ? gen_rtx_CLOBBER (tmode, const0_rtx) - : gen_rtx_combine (STRICT_LOW_PART, VOIDmode, new))); - - /* Otherwise, sign- or zero-extend unless we already are in the - proper mode. */ - - return (mode == tmode ? new - : gen_rtx_combine (unsignedp ? ZERO_EXTEND : SIGN_EXTEND, - mode, new)); - } - - /* Unless this is a COMPARE or we have a funny memory reference, - don't do anything with zero-extending field extracts starting at - the low-order bit since they are simple AND operations. */ - if (pos_rtx == 0 && pos == 0 && ! in_dest - && ! in_compare && ! spans_byte && unsignedp) - return 0; - - /* Unless we are allowed to span bytes, reject this if we would be - spanning bytes or if the position is not a constant and the length - is not 1. In all other cases, we would only be going outside - out object in cases when an original shift would have been - undefined. */ - if (! spans_byte - && ((pos_rtx == 0 && pos + len > GET_MODE_BITSIZE (is_mode)) - || (pos_rtx != 0 && len != 1))) - return 0; - - /* Get the mode to use should INNER not be a MEM, the mode for the position, - and the mode for the result. */ -#ifdef HAVE_insv - if (in_dest) - { - wanted_inner_reg_mode - = (insn_operand_mode[(int) CODE_FOR_insv][0] == VOIDmode - ? word_mode - : insn_operand_mode[(int) CODE_FOR_insv][0]); - pos_mode = (insn_operand_mode[(int) CODE_FOR_insv][2] == VOIDmode - ? word_mode : insn_operand_mode[(int) CODE_FOR_insv][2]); - extraction_mode = (insn_operand_mode[(int) CODE_FOR_insv][3] == VOIDmode - ? word_mode - : insn_operand_mode[(int) CODE_FOR_insv][3]); - } -#endif - -#ifdef HAVE_extzv - if (! in_dest && unsignedp) - { - wanted_inner_reg_mode - = (insn_operand_mode[(int) CODE_FOR_extzv][1] == VOIDmode - ? word_mode - : insn_operand_mode[(int) CODE_FOR_extzv][1]); - pos_mode = (insn_operand_mode[(int) CODE_FOR_extzv][3] == VOIDmode - ? word_mode : insn_operand_mode[(int) CODE_FOR_extzv][3]); - extraction_mode = (insn_operand_mode[(int) CODE_FOR_extzv][0] == VOIDmode - ? word_mode - : insn_operand_mode[(int) CODE_FOR_extzv][0]); - } -#endif - -#ifdef HAVE_extv - if (! in_dest && ! unsignedp) - { - wanted_inner_reg_mode - = (insn_operand_mode[(int) CODE_FOR_extv][1] == VOIDmode - ? word_mode - : insn_operand_mode[(int) CODE_FOR_extv][1]); - pos_mode = (insn_operand_mode[(int) CODE_FOR_extv][3] == VOIDmode - ? word_mode : insn_operand_mode[(int) CODE_FOR_extv][3]); - extraction_mode = (insn_operand_mode[(int) CODE_FOR_extv][0] == VOIDmode - ? word_mode - : insn_operand_mode[(int) CODE_FOR_extv][0]); - } -#endif - - /* Never narrow an object, since that might not be safe. */ - - if (mode != VOIDmode - && GET_MODE_SIZE (extraction_mode) < GET_MODE_SIZE (mode)) - extraction_mode = mode; - - if (pos_rtx && GET_MODE (pos_rtx) != VOIDmode - && GET_MODE_SIZE (pos_mode) < GET_MODE_SIZE (GET_MODE (pos_rtx))) - pos_mode = GET_MODE (pos_rtx); - - /* If this is not from memory, the desired mode is wanted_inner_reg_mode; - if we have to change the mode of memory and cannot, the desired mode is - EXTRACTION_MODE. */ - if (GET_CODE (inner) != MEM) - wanted_inner_mode = wanted_inner_reg_mode; - else if (inner_mode != wanted_inner_mode - && (mode_dependent_address_p (XEXP (inner, 0)) - || MEM_VOLATILE_P (inner))) - wanted_inner_mode = extraction_mode; - - orig_pos = pos; - - if (BITS_BIG_ENDIAN) - { - /* POS is passed as if BITS_BIG_ENDIAN == 0, so we need to convert it to - BITS_BIG_ENDIAN style. If position is constant, compute new - position. Otherwise, build subtraction. - Note that POS is relative to the mode of the original argument. - If it's a MEM we need to recompute POS relative to that. - However, if we're extracting from (or inserting into) a register, - we want to recompute POS relative to wanted_inner_mode. */ - int width = (GET_CODE (inner) == MEM - ? GET_MODE_BITSIZE (is_mode) - : GET_MODE_BITSIZE (wanted_inner_mode)); - - if (pos_rtx == 0) - pos = width - len - pos; - else - pos_rtx - = gen_rtx_combine (MINUS, GET_MODE (pos_rtx), - GEN_INT (width - len), pos_rtx); - /* POS may be less than 0 now, but we check for that below. - Note that it can only be less than 0 if GET_CODE (inner) != MEM. */ - } - - /* If INNER has a wider mode, make it smaller. If this is a constant - extract, try to adjust the byte to point to the byte containing - the value. */ - if (wanted_inner_mode != VOIDmode - && GET_MODE_SIZE (wanted_inner_mode) < GET_MODE_SIZE (is_mode) - && ((GET_CODE (inner) == MEM - && (inner_mode == wanted_inner_mode - || (! mode_dependent_address_p (XEXP (inner, 0)) - && ! MEM_VOLATILE_P (inner)))))) - { - int offset = 0; - - /* The computations below will be correct if the machine is big - endian in both bits and bytes or little endian in bits and bytes. - If it is mixed, we must adjust. */ - - /* If bytes are big endian and we had a paradoxical SUBREG, we must - adjust OFFSET to compensate. */ - if (BYTES_BIG_ENDIAN - && ! spans_byte - && GET_MODE_SIZE (inner_mode) < GET_MODE_SIZE (is_mode)) - offset -= GET_MODE_SIZE (is_mode) - GET_MODE_SIZE (inner_mode); - - /* If this is a constant position, we can move to the desired byte. */ - if (pos_rtx == 0) - { - offset += pos / BITS_PER_UNIT; - pos %= GET_MODE_BITSIZE (wanted_inner_mode); - } - - if (BYTES_BIG_ENDIAN != BITS_BIG_ENDIAN - && ! spans_byte - && is_mode != wanted_inner_mode) - offset = (GET_MODE_SIZE (is_mode) - - GET_MODE_SIZE (wanted_inner_mode) - offset); - - if (offset != 0 || inner_mode != wanted_inner_mode) - { - rtx newmem = gen_rtx_MEM (wanted_inner_mode, - plus_constant (XEXP (inner, 0), offset)); - RTX_UNCHANGING_P (newmem) = RTX_UNCHANGING_P (inner); - MEM_COPY_ATTRIBUTES (newmem, inner); - inner = newmem; - } - } - - /* If INNER is not memory, we can always get it into the proper mode. If we - are changing its mode, POS must be a constant and smaller than the size - of the new mode. */ - else if (GET_CODE (inner) != MEM) - { - if (GET_MODE (inner) != wanted_inner_mode - && (pos_rtx != 0 - || orig_pos + len > GET_MODE_BITSIZE (wanted_inner_mode))) - return 0; - - inner = force_to_mode (inner, wanted_inner_mode, - pos_rtx - || len + orig_pos >= HOST_BITS_PER_WIDE_INT - ? GET_MODE_MASK (wanted_inner_mode) - : (((HOST_WIDE_INT) 1 << len) - 1) << orig_pos, - NULL_RTX, 0); - } - - /* Adjust mode of POS_RTX, if needed. If we want a wider mode, we - have to zero extend. Otherwise, we can just use a SUBREG. */ - if (pos_rtx != 0 - && GET_MODE_SIZE (pos_mode) > GET_MODE_SIZE (GET_MODE (pos_rtx))) - pos_rtx = gen_rtx_combine (ZERO_EXTEND, pos_mode, pos_rtx); - else if (pos_rtx != 0 - && GET_MODE_SIZE (pos_mode) < GET_MODE_SIZE (GET_MODE (pos_rtx))) - pos_rtx = gen_lowpart_for_combine (pos_mode, pos_rtx); - - /* Make POS_RTX unless we already have it and it is correct. If we don't - have a POS_RTX but we do have an ORIG_POS_RTX, the latter must - be a CONST_INT. */ - if (pos_rtx == 0 && orig_pos_rtx != 0 && INTVAL (orig_pos_rtx) == pos) - pos_rtx = orig_pos_rtx; - - else if (pos_rtx == 0) - pos_rtx = GEN_INT (pos); - - /* Make the required operation. See if we can use existing rtx. */ - new = gen_rtx_combine (unsignedp ? ZERO_EXTRACT : SIGN_EXTRACT, - extraction_mode, inner, GEN_INT (len), pos_rtx); - if (! in_dest) - new = gen_lowpart_for_combine (mode, new); - - return new; -} - -/* See if X contains an ASHIFT of COUNT or more bits that can be commuted - with any other operations in X. Return X without that shift if so. */ - -static rtx -extract_left_shift (x, count) - rtx x; - int count; -{ - enum rtx_code code = GET_CODE (x); - enum machine_mode mode = GET_MODE (x); - rtx tem; - - switch (code) - { - case ASHIFT: - /* This is the shift itself. If it is wide enough, we will return - either the value being shifted if the shift count is equal to - COUNT or a shift for the difference. */ - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) >= count) - return simplify_shift_const (NULL_RTX, ASHIFT, mode, XEXP (x, 0), - INTVAL (XEXP (x, 1)) - count); - break; - - case NEG: case NOT: - if ((tem = extract_left_shift (XEXP (x, 0), count)) != 0) - return gen_unary (code, mode, mode, tem); - - break; - - case PLUS: case IOR: case XOR: case AND: - /* If we can safely shift this constant and we find the inner shift, - make a new operation. */ - if (GET_CODE (XEXP (x,1)) == CONST_INT - && (INTVAL (XEXP (x, 1)) & ((((HOST_WIDE_INT) 1 << count)) - 1)) == 0 - && (tem = extract_left_shift (XEXP (x, 0), count)) != 0) - return gen_binary (code, mode, tem, - GEN_INT (INTVAL (XEXP (x, 1)) >> count)); - - break; - - default: - break; - } - - return 0; -} - -/* Look at the expression rooted at X. Look for expressions - equivalent to ZERO_EXTRACT, SIGN_EXTRACT, ZERO_EXTEND, SIGN_EXTEND. - Form these expressions. - - Return the new rtx, usually just X. - - Also, for machines like the Vax that don't have logical shift insns, - try to convert logical to arithmetic shift operations in cases where - they are equivalent. This undoes the canonicalizations to logical - shifts done elsewhere. - - We try, as much as possible, to re-use rtl expressions to save memory. - - IN_CODE says what kind of expression we are processing. Normally, it is - SET. In a memory address (inside a MEM, PLUS or minus, the latter two - being kludges), it is MEM. When processing the arguments of a comparison - or a COMPARE against zero, it is COMPARE. */ - -static rtx -make_compound_operation (x, in_code) - rtx x; - enum rtx_code in_code; -{ - enum rtx_code code = GET_CODE (x); - enum machine_mode mode = GET_MODE (x); - int mode_width = GET_MODE_BITSIZE (mode); - rtx rhs, lhs; - enum rtx_code next_code; - int i; - rtx new = 0; - rtx tem; - char *fmt; - - /* Select the code to be used in recursive calls. Once we are inside an - address, we stay there. If we have a comparison, set to COMPARE, - but once inside, go back to our default of SET. */ - - next_code = (code == MEM || code == PLUS || code == MINUS ? MEM - : ((code == COMPARE || GET_RTX_CLASS (code) == '<') - && XEXP (x, 1) == const0_rtx) ? COMPARE - : in_code == COMPARE ? SET : in_code); - - /* Process depending on the code of this operation. If NEW is set - non-zero, it will be returned. */ - - switch (code) - { - case ASHIFT: - /* Convert shifts by constants into multiplications if inside - an address. */ - if (in_code == MEM && GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT - && INTVAL (XEXP (x, 1)) >= 0) - { - new = make_compound_operation (XEXP (x, 0), next_code); - new = gen_rtx_combine (MULT, mode, new, - GEN_INT ((HOST_WIDE_INT) 1 - << INTVAL (XEXP (x, 1)))); - } - break; - - case AND: - /* If the second operand is not a constant, we can't do anything - with it. */ - if (GET_CODE (XEXP (x, 1)) != CONST_INT) - break; - - /* If the constant is a power of two minus one and the first operand - is a logical right shift, make an extraction. */ - if (GET_CODE (XEXP (x, 0)) == LSHIFTRT - && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) - { - new = make_compound_operation (XEXP (XEXP (x, 0), 0), next_code); - new = make_extraction (mode, new, 0, XEXP (XEXP (x, 0), 1), i, 1, - 0, in_code == COMPARE); - } - - /* Same as previous, but for (subreg (lshiftrt ...)) in first op. */ - else if (GET_CODE (XEXP (x, 0)) == SUBREG - && subreg_lowpart_p (XEXP (x, 0)) - && GET_CODE (SUBREG_REG (XEXP (x, 0))) == LSHIFTRT - && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) - { - new = make_compound_operation (XEXP (SUBREG_REG (XEXP (x, 0)), 0), - next_code); - new = make_extraction (GET_MODE (SUBREG_REG (XEXP (x, 0))), new, 0, - XEXP (SUBREG_REG (XEXP (x, 0)), 1), i, 1, - 0, in_code == COMPARE); - } - /* Same as previous, but for (xor/ior (lshiftrt...) (lshiftrt...)). */ - else if ((GET_CODE (XEXP (x, 0)) == XOR - || GET_CODE (XEXP (x, 0)) == IOR) - && GET_CODE (XEXP (XEXP (x, 0), 0)) == LSHIFTRT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == LSHIFTRT - && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) - { - /* Apply the distributive law, and then try to make extractions. */ - new = gen_rtx_combine (GET_CODE (XEXP (x, 0)), mode, - gen_rtx_AND (mode, XEXP (XEXP (x, 0), 0), - XEXP (x, 1)), - gen_rtx_AND (mode, XEXP (XEXP (x, 0), 1), - XEXP (x, 1))); - new = make_compound_operation (new, in_code); - } - - /* If we are have (and (rotate X C) M) and C is larger than the number - of bits in M, this is an extraction. */ - - else if (GET_CODE (XEXP (x, 0)) == ROTATE - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0 - && i <= INTVAL (XEXP (XEXP (x, 0), 1))) - { - new = make_compound_operation (XEXP (XEXP (x, 0), 0), next_code); - new = make_extraction (mode, new, - (GET_MODE_BITSIZE (mode) - - INTVAL (XEXP (XEXP (x, 0), 1))), - NULL_RTX, i, 1, 0, in_code == COMPARE); - } - - /* On machines without logical shifts, if the operand of the AND is - a logical shift and our mask turns off all the propagated sign - bits, we can replace the logical shift with an arithmetic shift. */ - else if (ashr_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing - && (lshr_optab->handlers[(int) mode].insn_code - == CODE_FOR_nothing) - && GET_CODE (XEXP (x, 0)) == LSHIFTRT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (x, 0), 1)) >= 0 - && INTVAL (XEXP (XEXP (x, 0), 1)) < HOST_BITS_PER_WIDE_INT - && mode_width <= HOST_BITS_PER_WIDE_INT) - { - unsigned HOST_WIDE_INT mask = GET_MODE_MASK (mode); - - mask >>= INTVAL (XEXP (XEXP (x, 0), 1)); - if ((INTVAL (XEXP (x, 1)) & ~mask) == 0) - SUBST (XEXP (x, 0), - gen_rtx_combine (ASHIFTRT, mode, - make_compound_operation (XEXP (XEXP (x, 0), 0), - next_code), - XEXP (XEXP (x, 0), 1))); - } - - /* If the constant is one less than a power of two, this might be - representable by an extraction even if no shift is present. - If it doesn't end up being a ZERO_EXTEND, we will ignore it unless - we are in a COMPARE. */ - else if ((i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) - new = make_extraction (mode, - make_compound_operation (XEXP (x, 0), - next_code), - 0, NULL_RTX, i, 1, 0, in_code == COMPARE); - - /* If we are in a comparison and this is an AND with a power of two, - convert this into the appropriate bit extract. */ - else if (in_code == COMPARE - && (i = exact_log2 (INTVAL (XEXP (x, 1)))) >= 0) - new = make_extraction (mode, - make_compound_operation (XEXP (x, 0), - next_code), - i, NULL_RTX, 1, 1, 0, 1); - - break; - - case LSHIFTRT: - /* If the sign bit is known to be zero, replace this with an - arithmetic shift. */ - if (ashr_optab->handlers[(int) mode].insn_code == CODE_FOR_nothing - && lshr_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing - && mode_width <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (XEXP (x, 0), mode) & (1 << (mode_width - 1))) == 0) - { - new = gen_rtx_combine (ASHIFTRT, mode, - make_compound_operation (XEXP (x, 0), - next_code), - XEXP (x, 1)); - break; - } - - /* ... fall through ... */ - - case ASHIFTRT: - lhs = XEXP (x, 0); - rhs = XEXP (x, 1); - - /* If we have (ashiftrt (ashift foo C1) C2) with C2 >= C1, - this is a SIGN_EXTRACT. */ - if (GET_CODE (rhs) == CONST_INT - && GET_CODE (lhs) == ASHIFT - && GET_CODE (XEXP (lhs, 1)) == CONST_INT - && INTVAL (rhs) >= INTVAL (XEXP (lhs, 1))) - { - new = make_compound_operation (XEXP (lhs, 0), next_code); - new = make_extraction (mode, new, - INTVAL (rhs) - INTVAL (XEXP (lhs, 1)), - NULL_RTX, mode_width - INTVAL (rhs), - code == LSHIFTRT, 0, in_code == COMPARE); - } - - /* See if we have operations between an ASHIFTRT and an ASHIFT. - If so, try to merge the shifts into a SIGN_EXTEND. We could - also do this for some cases of SIGN_EXTRACT, but it doesn't - seem worth the effort; the case checked for occurs on Alpha. */ - - if (GET_RTX_CLASS (GET_CODE (lhs)) != 'o' - && ! (GET_CODE (lhs) == SUBREG - && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (lhs))) == 'o')) - && GET_CODE (rhs) == CONST_INT - && INTVAL (rhs) < HOST_BITS_PER_WIDE_INT - && (new = extract_left_shift (lhs, INTVAL (rhs))) != 0) - new = make_extraction (mode, make_compound_operation (new, next_code), - 0, NULL_RTX, mode_width - INTVAL (rhs), - code == LSHIFTRT, 0, in_code == COMPARE); - - break; - - case SUBREG: - /* Call ourselves recursively on the inner expression. If we are - narrowing the object and it has a different RTL code from - what it originally did, do this SUBREG as a force_to_mode. */ - - tem = make_compound_operation (SUBREG_REG (x), in_code); - if (GET_CODE (tem) != GET_CODE (SUBREG_REG (x)) - && GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (tem)) - && subreg_lowpart_p (x)) - { - rtx newer = force_to_mode (tem, mode, - GET_MODE_MASK (mode), NULL_RTX, 0); - - /* If we have something other than a SUBREG, we might have - done an expansion, so rerun outselves. */ - if (GET_CODE (newer) != SUBREG) - newer = make_compound_operation (newer, in_code); - - return newer; - } - - /* If this is a paradoxical subreg, and the new code is a sign or - zero extension, omit the subreg and widen the extension. If it - is a regular subreg, we can still get rid of the subreg by not - widening so much, or in fact removing the extension entirely. */ - if ((GET_CODE (tem) == SIGN_EXTEND - || GET_CODE (tem) == ZERO_EXTEND) - && subreg_lowpart_p (x)) - { - if (GET_MODE_SIZE (mode) > GET_MODE_SIZE (GET_MODE (tem)) - || (GET_MODE_SIZE (mode) > - GET_MODE_SIZE (GET_MODE (XEXP (tem, 0))))) - tem = gen_rtx_combine (GET_CODE (tem), mode, XEXP (tem, 0)); - else - tem = gen_lowpart_for_combine (mode, XEXP (tem, 0)); - return tem; - } - break; - - default: - break; - } - - if (new) - { - x = gen_lowpart_for_combine (mode, new); - code = GET_CODE (x); - } - - /* Now recursively process each operand of this operation. */ - fmt = GET_RTX_FORMAT (code); - for (i = 0; i < GET_RTX_LENGTH (code); i++) - if (fmt[i] == 'e') - { - new = make_compound_operation (XEXP (x, i), next_code); - SUBST (XEXP (x, i), new); - } - - return x; -} - -/* Given M see if it is a value that would select a field of bits - within an item, but not the entire word. Return -1 if not. - Otherwise, return the starting position of the field, where 0 is the - low-order bit. - - *PLEN is set to the length of the field. */ - -static int -get_pos_from_mask (m, plen) - unsigned HOST_WIDE_INT m; - int *plen; -{ - /* Get the bit number of the first 1 bit from the right, -1 if none. */ - int pos = exact_log2 (m & - m); - - if (pos < 0) - return -1; - - /* Now shift off the low-order zero bits and see if we have a power of - two minus 1. */ - *plen = exact_log2 ((m >> pos) + 1); - - if (*plen <= 0) - return -1; - - return pos; -} - -/* See if X can be simplified knowing that we will only refer to it in - MODE and will only refer to those bits that are nonzero in MASK. - If other bits are being computed or if masking operations are done - that select a superset of the bits in MASK, they can sometimes be - ignored. - - Return a possibly simplified expression, but always convert X to - MODE. If X is a CONST_INT, AND the CONST_INT with MASK. - - Also, if REG is non-zero and X is a register equal in value to REG, - replace X with REG. - - If JUST_SELECT is nonzero, don't optimize by noticing that bits in MASK - are all off in X. This is used when X will be complemented, by either - NOT, NEG, or XOR. */ - -static rtx -force_to_mode (x, mode, mask, reg, just_select) - rtx x; - enum machine_mode mode; - unsigned HOST_WIDE_INT mask; - rtx reg; - int just_select; -{ - enum rtx_code code = GET_CODE (x); - int next_select = just_select || code == XOR || code == NOT || code == NEG; - enum machine_mode op_mode; - unsigned HOST_WIDE_INT fuller_mask, nonzero; - rtx op0, op1, temp; - - /* If this is a CALL or ASM_OPERANDS, don't do anything. Some of the - code below will do the wrong thing since the mode of such an - expression is VOIDmode. - - Also do nothing if X is a CLOBBER; this can happen if X was - the return value from a call to gen_lowpart_for_combine. */ - if (code == CALL || code == ASM_OPERANDS || code == CLOBBER) - return x; - - /* We want to perform the operation is its present mode unless we know - that the operation is valid in MODE, in which case we do the operation - in MODE. */ - op_mode = ((GET_MODE_CLASS (mode) == GET_MODE_CLASS (GET_MODE (x)) - && code_to_optab[(int) code] != 0 - && (code_to_optab[(int) code]->handlers[(int) mode].insn_code - != CODE_FOR_nothing)) - ? mode : GET_MODE (x)); - - /* It is not valid to do a right-shift in a narrower mode - than the one it came in with. */ - if ((code == LSHIFTRT || code == ASHIFTRT) - && GET_MODE_BITSIZE (mode) < GET_MODE_BITSIZE (GET_MODE (x))) - op_mode = GET_MODE (x); - - /* Truncate MASK to fit OP_MODE. */ - if (op_mode) - mask &= GET_MODE_MASK (op_mode); - - /* When we have an arithmetic operation, or a shift whose count we - do not know, we need to assume that all bit the up to the highest-order - bit in MASK will be needed. This is how we form such a mask. */ - if (op_mode) - fuller_mask = (GET_MODE_BITSIZE (op_mode) >= HOST_BITS_PER_WIDE_INT - ? GET_MODE_MASK (op_mode) - : ((HOST_WIDE_INT) 1 << (floor_log2 (mask) + 1)) - 1); - else - fuller_mask = ~ (HOST_WIDE_INT) 0; - - /* Determine what bits of X are guaranteed to be (non)zero. */ - nonzero = nonzero_bits (x, mode); - - /* If none of the bits in X are needed, return a zero. */ - if (! just_select && (nonzero & mask) == 0) - return const0_rtx; - - /* If X is a CONST_INT, return a new one. Do this here since the - test below will fail. */ - if (GET_CODE (x) == CONST_INT) - { - HOST_WIDE_INT cval = INTVAL (x) & mask; - int width = GET_MODE_BITSIZE (mode); - - /* If MODE is narrower that HOST_WIDE_INT and CVAL is a negative - number, sign extend it. */ - if (width > 0 && width < HOST_BITS_PER_WIDE_INT - && (cval & ((HOST_WIDE_INT) 1 << (width - 1))) != 0) - cval |= (HOST_WIDE_INT) -1 << width; - - return GEN_INT (cval); - } - - /* If X is narrower than MODE and we want all the bits in X's mode, just - get X in the proper mode. */ - if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (mode) - && (GET_MODE_MASK (GET_MODE (x)) & ~ mask) == 0) - return gen_lowpart_for_combine (mode, x); - - /* If we aren't changing the mode, X is not a SUBREG, and all zero bits in - MASK are already known to be zero in X, we need not do anything. */ - if (GET_MODE (x) == mode && code != SUBREG && (~ mask & nonzero) == 0) - return x; - - switch (code) - { - case CLOBBER: - /* If X is a (clobber (const_int)), return it since we know we are - generating something that won't match. */ - return x; - - case USE: - /* X is a (use (mem ..)) that was made from a bit-field extraction that - spanned the boundary of the MEM. If we are now masking so it is - within that boundary, we don't need the USE any more. */ - if (! BITS_BIG_ENDIAN - && (mask & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) == 0) - return force_to_mode (XEXP (x, 0), mode, mask, reg, next_select); - break; - - case SIGN_EXTEND: - case ZERO_EXTEND: - case ZERO_EXTRACT: - case SIGN_EXTRACT: - x = expand_compound_operation (x); - if (GET_CODE (x) != code) - return force_to_mode (x, mode, mask, reg, next_select); - break; - - case REG: - if (reg != 0 && (rtx_equal_p (get_last_value (reg), x) - || rtx_equal_p (reg, get_last_value (x)))) - x = reg; - break; - - case SUBREG: - if (subreg_lowpart_p (x) - /* We can ignore the effect of this SUBREG if it narrows the mode or - if the constant masks to zero all the bits the mode doesn't - have. */ - && ((GET_MODE_SIZE (GET_MODE (x)) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) - || (0 == (mask - & GET_MODE_MASK (GET_MODE (x)) - & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x))))))) - return force_to_mode (SUBREG_REG (x), mode, mask, reg, next_select); - break; - - case AND: - /* If this is an AND with a constant, convert it into an AND - whose constant is the AND of that constant with MASK. If it - remains an AND of MASK, delete it since it is redundant. */ - - if (GET_CODE (XEXP (x, 1)) == CONST_INT) - { - x = simplify_and_const_int (x, op_mode, XEXP (x, 0), - mask & INTVAL (XEXP (x, 1))); - - /* If X is still an AND, see if it is an AND with a mask that - is just some low-order bits. If so, and it is MASK, we don't - need it. */ - - if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT - && (unsigned HOST_WIDE_INT) INTVAL (XEXP (x, 1)) == mask) - x = XEXP (x, 0); - - /* If it remains an AND, try making another AND with the bits - in the mode mask that aren't in MASK turned on. If the - constant in the AND is wide enough, this might make a - cheaper constant. */ - - if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT - && GET_MODE_MASK (GET_MODE (x)) != mask - && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT) - { - HOST_WIDE_INT cval = (INTVAL (XEXP (x, 1)) - | (GET_MODE_MASK (GET_MODE (x)) & ~ mask)); - int width = GET_MODE_BITSIZE (GET_MODE (x)); - rtx y; - - /* If MODE is narrower that HOST_WIDE_INT and CVAL is a negative - number, sign extend it. */ - if (width > 0 && width < HOST_BITS_PER_WIDE_INT - && (cval & ((HOST_WIDE_INT) 1 << (width - 1))) != 0) - cval |= (HOST_WIDE_INT) -1 << width; - - y = gen_binary (AND, GET_MODE (x), XEXP (x, 0), GEN_INT (cval)); - if (rtx_cost (y, SET) < rtx_cost (x, SET)) - x = y; - } - - break; - } - - goto binop; - - case PLUS: - /* In (and (plus FOO C1) M), if M is a mask that just turns off - low-order bits (as in an alignment operation) and FOO is already - aligned to that boundary, mask C1 to that boundary as well. - This may eliminate that PLUS and, later, the AND. */ - - { - int width = GET_MODE_BITSIZE (mode); - unsigned HOST_WIDE_INT smask = mask; - - /* If MODE is narrower than HOST_WIDE_INT and mask is a negative - number, sign extend it. */ - - if (width < HOST_BITS_PER_WIDE_INT - && (smask & ((HOST_WIDE_INT) 1 << (width - 1))) != 0) - smask |= (HOST_WIDE_INT) -1 << width; - - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && exact_log2 (- smask) >= 0) - { -#ifdef STACK_BIAS - if (STACK_BIAS - && (XEXP (x, 0) == stack_pointer_rtx - || XEXP (x, 0) == frame_pointer_rtx)) - { - int sp_alignment = STACK_BOUNDARY / BITS_PER_UNIT; - unsigned HOST_WIDE_INT sp_mask = GET_MODE_MASK (mode); - - sp_mask &= ~ (sp_alignment - 1); - if ((sp_mask & ~ smask) == 0 - && ((INTVAL (XEXP (x, 1)) - STACK_BIAS) & ~ smask) != 0) - return force_to_mode (plus_constant (XEXP (x, 0), - ((INTVAL (XEXP (x, 1)) - - STACK_BIAS) & smask) - + STACK_BIAS), - mode, smask, reg, next_select); - } -#endif - if ((nonzero_bits (XEXP (x, 0), mode) & ~ smask) == 0 - && (INTVAL (XEXP (x, 1)) & ~ smask) != 0) - return force_to_mode (plus_constant (XEXP (x, 0), - (INTVAL (XEXP (x, 1)) - & smask)), - mode, smask, reg, next_select); - } - } - - /* ... fall through ... */ - - case MINUS: - case MULT: - /* For PLUS, MINUS and MULT, we need any bits less significant than the - most significant bit in MASK since carries from those bits will - affect the bits we are interested in. */ - mask = fuller_mask; - goto binop; - - case IOR: - case XOR: - /* If X is (ior (lshiftrt FOO C1) C2), try to commute the IOR and - LSHIFTRT so we end up with an (and (lshiftrt (ior ...) ...) ...) - operation which may be a bitfield extraction. Ensure that the - constant we form is not wider than the mode of X. */ - - if (GET_CODE (XEXP (x, 0)) == LSHIFTRT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (x, 0), 1)) >= 0 - && INTVAL (XEXP (XEXP (x, 0), 1)) < HOST_BITS_PER_WIDE_INT - && GET_CODE (XEXP (x, 1)) == CONST_INT - && ((INTVAL (XEXP (XEXP (x, 0), 1)) - + floor_log2 (INTVAL (XEXP (x, 1)))) - < GET_MODE_BITSIZE (GET_MODE (x))) - && (INTVAL (XEXP (x, 1)) - & ~ nonzero_bits (XEXP (x, 0), GET_MODE (x))) == 0) - { - temp = GEN_INT ((INTVAL (XEXP (x, 1)) & mask) - << INTVAL (XEXP (XEXP (x, 0), 1))); - temp = gen_binary (GET_CODE (x), GET_MODE (x), - XEXP (XEXP (x, 0), 0), temp); - x = gen_binary (LSHIFTRT, GET_MODE (x), temp, - XEXP (XEXP (x, 0), 1)); - return force_to_mode (x, mode, mask, reg, next_select); - } - - binop: - /* For most binary operations, just propagate into the operation and - change the mode if we have an operation of that mode. */ - - op0 = gen_lowpart_for_combine (op_mode, - force_to_mode (XEXP (x, 0), mode, mask, - reg, next_select)); - op1 = gen_lowpart_for_combine (op_mode, - force_to_mode (XEXP (x, 1), mode, mask, - reg, next_select)); - - /* If OP1 is a CONST_INT and X is an IOR or XOR, clear bits outside - MASK since OP1 might have been sign-extended but we never want - to turn on extra bits, since combine might have previously relied - on them being off. */ - if (GET_CODE (op1) == CONST_INT && (code == IOR || code == XOR) - && (INTVAL (op1) & mask) != 0) - op1 = GEN_INT (INTVAL (op1) & mask); - - if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) - x = gen_binary (code, op_mode, op0, op1); - break; - - case ASHIFT: - /* For left shifts, do the same, but just for the first operand. - However, we cannot do anything with shifts where we cannot - guarantee that the counts are smaller than the size of the mode - because such a count will have a different meaning in a - wider mode. */ - - if (! (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) >= 0 - && INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (mode)) - && ! (GET_MODE (XEXP (x, 1)) != VOIDmode - && (nonzero_bits (XEXP (x, 1), GET_MODE (XEXP (x, 1))) - < (unsigned HOST_WIDE_INT) GET_MODE_BITSIZE (mode)))) - break; - - /* If the shift count is a constant and we can do arithmetic in - the mode of the shift, refine which bits we need. Otherwise, use the - conservative form of the mask. */ - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) >= 0 - && INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (op_mode) - && GET_MODE_BITSIZE (op_mode) <= HOST_BITS_PER_WIDE_INT) - mask >>= INTVAL (XEXP (x, 1)); - else - mask = fuller_mask; - - op0 = gen_lowpart_for_combine (op_mode, - force_to_mode (XEXP (x, 0), op_mode, - mask, reg, next_select)); - - if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0)) - x = gen_binary (code, op_mode, op0, XEXP (x, 1)); - break; - - case LSHIFTRT: - /* Here we can only do something if the shift count is a constant, - this shift constant is valid for the host, and we can do arithmetic - in OP_MODE. */ - - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT - && GET_MODE_BITSIZE (op_mode) <= HOST_BITS_PER_WIDE_INT) - { - rtx inner = XEXP (x, 0); - - /* Select the mask of the bits we need for the shift operand. */ - mask <<= INTVAL (XEXP (x, 1)); - - /* We can only change the mode of the shift if we can do arithmetic - in the mode of the shift and MASK is no wider than the width of - OP_MODE. */ - if (GET_MODE_BITSIZE (op_mode) > HOST_BITS_PER_WIDE_INT - || (mask & ~ GET_MODE_MASK (op_mode)) != 0) - op_mode = GET_MODE (x); - - inner = force_to_mode (inner, op_mode, mask, reg, next_select); - - if (GET_MODE (x) != op_mode || inner != XEXP (x, 0)) - x = gen_binary (LSHIFTRT, op_mode, inner, XEXP (x, 1)); - } - - /* If we have (and (lshiftrt FOO C1) C2) where the combination of the - shift and AND produces only copies of the sign bit (C2 is one less - than a power of two), we can do this with just a shift. */ - - if (GET_CODE (x) == LSHIFTRT - && GET_CODE (XEXP (x, 1)) == CONST_INT - && ((INTVAL (XEXP (x, 1)) - + num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0)))) - >= GET_MODE_BITSIZE (GET_MODE (x))) - && exact_log2 (mask + 1) >= 0 - && (num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0))) - >= exact_log2 (mask + 1))) - x = gen_binary (LSHIFTRT, GET_MODE (x), XEXP (x, 0), - GEN_INT (GET_MODE_BITSIZE (GET_MODE (x)) - - exact_log2 (mask + 1))); - break; - - case ASHIFTRT: - /* If we are just looking for the sign bit, we don't need this shift at - all, even if it has a variable count. */ - if (GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT - && (mask == ((unsigned HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (GET_MODE (x)) - 1)))) - return force_to_mode (XEXP (x, 0), mode, mask, reg, next_select); - - /* If this is a shift by a constant, get a mask that contains those bits - that are not copies of the sign bit. We then have two cases: If - MASK only includes those bits, this can be a logical shift, which may - allow simplifications. If MASK is a single-bit field not within - those bits, we are requesting a copy of the sign bit and hence can - shift the sign bit to the appropriate location. */ - - if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) >= 0 - && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT) - { - int i = -1; - - /* If the considered data is wider then HOST_WIDE_INT, we can't - represent a mask for all its bits in a single scalar. - But we only care about the lower bits, so calculate these. */ - - if (GET_MODE_BITSIZE (GET_MODE (x)) > HOST_BITS_PER_WIDE_INT) - { - nonzero = ~ (HOST_WIDE_INT) 0; - - /* GET_MODE_BITSIZE (GET_MODE (x)) - INTVAL (XEXP (x, 1)) - is the number of bits a full-width mask would have set. - We need only shift if these are fewer than nonzero can - hold. If not, we must keep all bits set in nonzero. */ - - if (GET_MODE_BITSIZE (GET_MODE (x)) - INTVAL (XEXP (x, 1)) - < HOST_BITS_PER_WIDE_INT) - nonzero >>= INTVAL (XEXP (x, 1)) - + HOST_BITS_PER_WIDE_INT - - GET_MODE_BITSIZE (GET_MODE (x)) ; - } - else - { - nonzero = GET_MODE_MASK (GET_MODE (x)); - nonzero >>= INTVAL (XEXP (x, 1)); - } - - if ((mask & ~ nonzero) == 0 - || (i = exact_log2 (mask)) >= 0) - { - x = simplify_shift_const - (x, LSHIFTRT, GET_MODE (x), XEXP (x, 0), - i < 0 ? INTVAL (XEXP (x, 1)) - : GET_MODE_BITSIZE (GET_MODE (x)) - 1 - i); - - if (GET_CODE (x) != ASHIFTRT) - return force_to_mode (x, mode, mask, reg, next_select); - } - } - - /* If MASK is 1, convert this to a LSHIFTRT. This can be done - even if the shift count isn't a constant. */ - if (mask == 1) - x = gen_binary (LSHIFTRT, GET_MODE (x), XEXP (x, 0), XEXP (x, 1)); - - /* If this is a sign-extension operation that just affects bits - we don't care about, remove it. Be sure the call above returned - something that is still a shift. */ - - if ((GET_CODE (x) == LSHIFTRT || GET_CODE (x) == ASHIFTRT) - && GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) >= 0 - && (INTVAL (XEXP (x, 1)) - <= GET_MODE_BITSIZE (GET_MODE (x)) - (floor_log2 (mask) + 1)) - && GET_CODE (XEXP (x, 0)) == ASHIFT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (x, 0), 1)) == INTVAL (XEXP (x, 1))) - return force_to_mode (XEXP (XEXP (x, 0), 0), mode, mask, - reg, next_select); - - break; - - case ROTATE: - case ROTATERT: - /* If the shift count is constant and we can do computations - in the mode of X, compute where the bits we care about are. - Otherwise, we can't do anything. Don't change the mode of - the shift or propagate MODE into the shift, though. */ - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) >= 0) - { - temp = simplify_binary_operation (code == ROTATE ? ROTATERT : ROTATE, - GET_MODE (x), GEN_INT (mask), - XEXP (x, 1)); - if (temp && GET_CODE(temp) == CONST_INT) - SUBST (XEXP (x, 0), - force_to_mode (XEXP (x, 0), GET_MODE (x), - INTVAL (temp), reg, next_select)); - } - break; - - case NEG: - /* If we just want the low-order bit, the NEG isn't needed since it - won't change the low-order bit. */ - if (mask == 1) - return force_to_mode (XEXP (x, 0), mode, mask, reg, just_select); - - /* We need any bits less significant than the most significant bit in - MASK since carries from those bits will affect the bits we are - interested in. */ - mask = fuller_mask; - goto unop; - - case NOT: - /* (not FOO) is (xor FOO CONST), so if FOO is an LSHIFTRT, we can do the - same as the XOR case above. Ensure that the constant we form is not - wider than the mode of X. */ - - if (GET_CODE (XEXP (x, 0)) == LSHIFTRT - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (x, 0), 1)) >= 0 - && (INTVAL (XEXP (XEXP (x, 0), 1)) + floor_log2 (mask) - < GET_MODE_BITSIZE (GET_MODE (x))) - && INTVAL (XEXP (XEXP (x, 0), 1)) < HOST_BITS_PER_WIDE_INT) - { - temp = GEN_INT (mask << INTVAL (XEXP (XEXP (x, 0), 1))); - temp = gen_binary (XOR, GET_MODE (x), XEXP (XEXP (x, 0), 0), temp); - x = gen_binary (LSHIFTRT, GET_MODE (x), temp, XEXP (XEXP (x, 0), 1)); - - return force_to_mode (x, mode, mask, reg, next_select); - } - - /* (and (not FOO) CONST) is (not (or FOO (not CONST))), so we must - use the full mask inside the NOT. */ - mask = fuller_mask; - - unop: - op0 = gen_lowpart_for_combine (op_mode, - force_to_mode (XEXP (x, 0), mode, mask, - reg, next_select)); - if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0)) - x = gen_unary (code, op_mode, op_mode, op0); - break; - - case NE: - /* (and (ne FOO 0) CONST) can be (and FOO CONST) if CONST is included - in STORE_FLAG_VALUE and FOO has a single bit that might be nonzero, - which is equal to STORE_FLAG_VALUE. */ - if ((mask & ~ STORE_FLAG_VALUE) == 0 && XEXP (x, 1) == const0_rtx - && exact_log2 (nonzero_bits (XEXP (x, 0), mode)) >= 0 - && nonzero_bits (XEXP (x, 0), mode) == STORE_FLAG_VALUE) - return force_to_mode (XEXP (x, 0), mode, mask, reg, next_select); - - break; - - case IF_THEN_ELSE: - /* We have no way of knowing if the IF_THEN_ELSE can itself be - written in a narrower mode. We play it safe and do not do so. */ - - SUBST (XEXP (x, 1), - gen_lowpart_for_combine (GET_MODE (x), - force_to_mode (XEXP (x, 1), mode, - mask, reg, next_select))); - SUBST (XEXP (x, 2), - gen_lowpart_for_combine (GET_MODE (x), - force_to_mode (XEXP (x, 2), mode, - mask, reg,next_select))); - break; - - default: - break; - } - - /* Ensure we return a value of the proper mode. */ - return gen_lowpart_for_combine (mode, x); -} - -/* Return nonzero if X is an expression that has one of two values depending on - whether some other value is zero or nonzero. In that case, we return the - value that is being tested, *PTRUE is set to the value if the rtx being - returned has a nonzero value, and *PFALSE is set to the other alternative. - - If we return zero, we set *PTRUE and *PFALSE to X. */ - -static rtx -if_then_else_cond (x, ptrue, pfalse) - rtx x; - rtx *ptrue, *pfalse; -{ - enum machine_mode mode = GET_MODE (x); - enum rtx_code code = GET_CODE (x); - int size = GET_MODE_BITSIZE (mode); - rtx cond0, cond1, true0, true1, false0, false1; - unsigned HOST_WIDE_INT nz; - - /* If this is a unary operation whose operand has one of two values, apply - our opcode to compute those values. */ - if (GET_RTX_CLASS (code) == '1' - && (cond0 = if_then_else_cond (XEXP (x, 0), &true0, &false0)) != 0) - { - *ptrue = gen_unary (code, mode, GET_MODE (XEXP (x, 0)), true0); - *pfalse = gen_unary (code, mode, GET_MODE (XEXP (x, 0)), false0); - return cond0; - } - - /* If this is a COMPARE, do nothing, since the IF_THEN_ELSE we would - make can't possibly match and would suppress other optimizations. */ - else if (code == COMPARE) - ; - - /* If this is a binary operation, see if either side has only one of two - values. If either one does or if both do and they are conditional on - the same value, compute the new true and false values. */ - else if (GET_RTX_CLASS (code) == 'c' || GET_RTX_CLASS (code) == '2' - || GET_RTX_CLASS (code) == '<') - { - cond0 = if_then_else_cond (XEXP (x, 0), &true0, &false0); - cond1 = if_then_else_cond (XEXP (x, 1), &true1, &false1); - - if ((cond0 != 0 || cond1 != 0) - && ! (cond0 != 0 && cond1 != 0 && ! rtx_equal_p (cond0, cond1))) - { - /* If if_then_else_cond returned zero, then true/false are the - same rtl. We must copy one of them to prevent invalid rtl - sharing. */ - if (cond0 == 0) - true0 = copy_rtx (true0); - else if (cond1 == 0) - true1 = copy_rtx (true1); - - *ptrue = gen_binary (code, mode, true0, true1); - *pfalse = gen_binary (code, mode, false0, false1); - return cond0 ? cond0 : cond1; - } - - /* See if we have PLUS, IOR, XOR, MINUS or UMAX, where one of the - operands is zero when the other is non-zero, and vice-versa, - and STORE_FLAG_VALUE is 1 or -1. */ - - if ((STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1) - && (code == PLUS || code == IOR || code == XOR || code == MINUS - || code == UMAX) - && GET_CODE (XEXP (x, 0)) == MULT && GET_CODE (XEXP (x, 1)) == MULT) - { - rtx op0 = XEXP (XEXP (x, 0), 1); - rtx op1 = XEXP (XEXP (x, 1), 1); - - cond0 = XEXP (XEXP (x, 0), 0); - cond1 = XEXP (XEXP (x, 1), 0); - - if (GET_RTX_CLASS (GET_CODE (cond0)) == '<' - && GET_RTX_CLASS (GET_CODE (cond1)) == '<' - && reversible_comparison_p (cond1) - && ((GET_CODE (cond0) == reverse_condition (GET_CODE (cond1)) - && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 0)) - && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 1))) - || ((swap_condition (GET_CODE (cond0)) - == reverse_condition (GET_CODE (cond1))) - && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 1)) - && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 0)))) - && ! side_effects_p (x)) - { - *ptrue = gen_binary (MULT, mode, op0, const_true_rtx); - *pfalse = gen_binary (MULT, mode, - (code == MINUS - ? gen_unary (NEG, mode, mode, op1) : op1), - const_true_rtx); - return cond0; - } - } - - /* Similarly for MULT, AND and UMIN, execpt that for these the result - is always zero. */ - if ((STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1) - && (code == MULT || code == AND || code == UMIN) - && GET_CODE (XEXP (x, 0)) == MULT && GET_CODE (XEXP (x, 1)) == MULT) - { - cond0 = XEXP (XEXP (x, 0), 0); - cond1 = XEXP (XEXP (x, 1), 0); - - if (GET_RTX_CLASS (GET_CODE (cond0)) == '<' - && GET_RTX_CLASS (GET_CODE (cond1)) == '<' - && reversible_comparison_p (cond1) - && ((GET_CODE (cond0) == reverse_condition (GET_CODE (cond1)) - && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 0)) - && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 1))) - || ((swap_condition (GET_CODE (cond0)) - == reverse_condition (GET_CODE (cond1))) - && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 1)) - && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 0)))) - && ! side_effects_p (x)) - { - *ptrue = *pfalse = const0_rtx; - return cond0; - } - } - } - - else if (code == IF_THEN_ELSE) - { - /* If we have IF_THEN_ELSE already, extract the condition and - canonicalize it if it is NE or EQ. */ - cond0 = XEXP (x, 0); - *ptrue = XEXP (x, 1), *pfalse = XEXP (x, 2); - if (GET_CODE (cond0) == NE && XEXP (cond0, 1) == const0_rtx) - return XEXP (cond0, 0); - else if (GET_CODE (cond0) == EQ && XEXP (cond0, 1) == const0_rtx) - { - *ptrue = XEXP (x, 2), *pfalse = XEXP (x, 1); - return XEXP (cond0, 0); - } - else - return cond0; - } - - /* If X is a normal SUBREG with both inner and outer modes integral, - we can narrow both the true and false values of the inner expression, - if there is a condition. */ - else if (code == SUBREG && GET_MODE_CLASS (mode) == MODE_INT - && GET_MODE_CLASS (GET_MODE (SUBREG_REG (x))) == MODE_INT - && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) - && 0 != (cond0 = if_then_else_cond (SUBREG_REG (x), - &true0, &false0))) - { - *ptrue = force_to_mode (true0, mode, GET_MODE_MASK (mode), NULL_RTX, 0); - *pfalse - = force_to_mode (false0, mode, GET_MODE_MASK (mode), NULL_RTX, 0); - - return cond0; - } - - /* If X is a constant, this isn't special and will cause confusions - if we treat it as such. Likewise if it is equivalent to a constant. */ - else if (CONSTANT_P (x) - || ((cond0 = get_last_value (x)) != 0 && CONSTANT_P (cond0))) - ; - - /* If X is known to be either 0 or -1, those are the true and - false values when testing X. */ - else if (num_sign_bit_copies (x, mode) == size) - { - *ptrue = constm1_rtx, *pfalse = const0_rtx; - return x; - } - - /* Likewise for 0 or a single bit. */ - else if (exact_log2 (nz = nonzero_bits (x, mode)) >= 0) - { - *ptrue = GEN_INT (nz), *pfalse = const0_rtx; - return x; - } - - /* Otherwise fail; show no condition with true and false values the same. */ - *ptrue = *pfalse = x; - return 0; -} - -/* Return the value of expression X given the fact that condition COND - is known to be true when applied to REG as its first operand and VAL - as its second. X is known to not be shared and so can be modified in - place. - - We only handle the simplest cases, and specifically those cases that - arise with IF_THEN_ELSE expressions. */ - -static rtx -known_cond (x, cond, reg, val) - rtx x; - enum rtx_code cond; - rtx reg, val; -{ - enum rtx_code code = GET_CODE (x); - rtx temp; - char *fmt; - int i, j; - - if (side_effects_p (x)) - return x; - - if (cond == EQ && rtx_equal_p (x, reg)) - return val; - - /* If X is (abs REG) and we know something about REG's relationship - with zero, we may be able to simplify this. */ - - if (code == ABS && rtx_equal_p (XEXP (x, 0), reg) && val == const0_rtx) - switch (cond) - { - case GE: case GT: case EQ: - return XEXP (x, 0); - case LT: case LE: - return gen_unary (NEG, GET_MODE (XEXP (x, 0)), GET_MODE (XEXP (x, 0)), - XEXP (x, 0)); - default: - break; - } - - /* The only other cases we handle are MIN, MAX, and comparisons if the - operands are the same as REG and VAL. */ - - else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == 'c') - { - if (rtx_equal_p (XEXP (x, 0), val)) - cond = swap_condition (cond), temp = val, val = reg, reg = temp; - - if (rtx_equal_p (XEXP (x, 0), reg) && rtx_equal_p (XEXP (x, 1), val)) - { - if (GET_RTX_CLASS (code) == '<') - return (comparison_dominates_p (cond, code) ? const_true_rtx - : (comparison_dominates_p (cond, - reverse_condition (code)) - ? const0_rtx : x)); - - else if (code == SMAX || code == SMIN - || code == UMIN || code == UMAX) - { - int unsignedp = (code == UMIN || code == UMAX); - - if (code == SMAX || code == UMAX) - cond = reverse_condition (cond); - - switch (cond) - { - case GE: case GT: - return unsignedp ? x : XEXP (x, 1); - case LE: case LT: - return unsignedp ? x : XEXP (x, 0); - case GEU: case GTU: - return unsignedp ? XEXP (x, 1) : x; - case LEU: case LTU: - return unsignedp ? XEXP (x, 0) : x; - default: - break; - } - } - } - } - - fmt = GET_RTX_FORMAT (code); - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - if (fmt[i] == 'e') - SUBST (XEXP (x, i), known_cond (XEXP (x, i), cond, reg, val)); - else if (fmt[i] == 'E') - for (j = XVECLEN (x, i) - 1; j >= 0; j--) - SUBST (XVECEXP (x, i, j), known_cond (XVECEXP (x, i, j), - cond, reg, val)); - } - - return x; -} - -/* See if X and Y are equal for the purposes of seeing if we can rewrite an - assignment as a field assignment. */ - -static int -rtx_equal_for_field_assignment_p (x, y) - rtx x; - rtx y; -{ - if (x == y || rtx_equal_p (x, y)) - return 1; - - if (x == 0 || y == 0 || GET_MODE (x) != GET_MODE (y)) - return 0; - - /* Check for a paradoxical SUBREG of a MEM compared with the MEM. - Note that all SUBREGs of MEM are paradoxical; otherwise they - would have been rewritten. */ - if (GET_CODE (x) == MEM && GET_CODE (y) == SUBREG - && GET_CODE (SUBREG_REG (y)) == MEM - && rtx_equal_p (SUBREG_REG (y), - gen_lowpart_for_combine (GET_MODE (SUBREG_REG (y)), x))) - return 1; - - if (GET_CODE (y) == MEM && GET_CODE (x) == SUBREG - && GET_CODE (SUBREG_REG (x)) == MEM - && rtx_equal_p (SUBREG_REG (x), - gen_lowpart_for_combine (GET_MODE (SUBREG_REG (x)), y))) - return 1; - - /* We used to see if get_last_value of X and Y were the same but that's - not correct. In one direction, we'll cause the assignment to have - the wrong destination and in the case, we'll import a register into this - insn that might have already have been dead. So fail if none of the - above cases are true. */ - return 0; -} - -/* See if X, a SET operation, can be rewritten as a bit-field assignment. - Return that assignment if so. - - We only handle the most common cases. */ - -static rtx -make_field_assignment (x) - rtx x; -{ - rtx dest = SET_DEST (x); - rtx src = SET_SRC (x); - rtx assign; - rtx rhs, lhs; - HOST_WIDE_INT c1; - int pos, len; - rtx other; - enum machine_mode mode; - - /* If SRC was (and (not (ashift (const_int 1) POS)) DEST), this is - a clear of a one-bit field. We will have changed it to - (and (rotate (const_int -2) POS) DEST), so check for that. Also check - for a SUBREG. */ - - if (GET_CODE (src) == AND && GET_CODE (XEXP (src, 0)) == ROTATE - && GET_CODE (XEXP (XEXP (src, 0), 0)) == CONST_INT - && INTVAL (XEXP (XEXP (src, 0), 0)) == -2 - && rtx_equal_for_field_assignment_p (dest, XEXP (src, 1))) - { - assign = make_extraction (VOIDmode, dest, 0, XEXP (XEXP (src, 0), 1), - 1, 1, 1, 0); - if (assign != 0) - return gen_rtx_SET (VOIDmode, assign, const0_rtx); - return x; - } - - else if (GET_CODE (src) == AND && GET_CODE (XEXP (src, 0)) == SUBREG - && subreg_lowpart_p (XEXP (src, 0)) - && (GET_MODE_SIZE (GET_MODE (XEXP (src, 0))) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (src, 0))))) - && GET_CODE (SUBREG_REG (XEXP (src, 0))) == ROTATE - && INTVAL (XEXP (SUBREG_REG (XEXP (src, 0)), 0)) == -2 - && rtx_equal_for_field_assignment_p (dest, XEXP (src, 1))) - { - assign = make_extraction (VOIDmode, dest, 0, - XEXP (SUBREG_REG (XEXP (src, 0)), 1), - 1, 1, 1, 0); - if (assign != 0) - return gen_rtx_SET (VOIDmode, assign, const0_rtx); - return x; - } - - /* If SRC is (ior (ashift (const_int 1) POS) DEST), this is a set of a - one-bit field. */ - else if (GET_CODE (src) == IOR && GET_CODE (XEXP (src, 0)) == ASHIFT - && XEXP (XEXP (src, 0), 0) == const1_rtx - && rtx_equal_for_field_assignment_p (dest, XEXP (src, 1))) - { - assign = make_extraction (VOIDmode, dest, 0, XEXP (XEXP (src, 0), 1), - 1, 1, 1, 0); - if (assign != 0) - return gen_rtx_SET (VOIDmode, assign, const1_rtx); - return x; - } - - /* The other case we handle is assignments into a constant-position - field. They look like (ior/xor (and DEST C1) OTHER). If C1 represents - a mask that has all one bits except for a group of zero bits and - OTHER is known to have zeros where C1 has ones, this is such an - assignment. Compute the position and length from C1. Shift OTHER - to the appropriate position, force it to the required mode, and - make the extraction. Check for the AND in both operands. */ - - if (GET_CODE (src) != IOR && GET_CODE (src) != XOR) - return x; - - rhs = expand_compound_operation (XEXP (src, 0)); - lhs = expand_compound_operation (XEXP (src, 1)); - - if (GET_CODE (rhs) == AND - && GET_CODE (XEXP (rhs, 1)) == CONST_INT - && rtx_equal_for_field_assignment_p (XEXP (rhs, 0), dest)) - c1 = INTVAL (XEXP (rhs, 1)), other = lhs; - else if (GET_CODE (lhs) == AND - && GET_CODE (XEXP (lhs, 1)) == CONST_INT - && rtx_equal_for_field_assignment_p (XEXP (lhs, 0), dest)) - c1 = INTVAL (XEXP (lhs, 1)), other = rhs; - else - return x; - - pos = get_pos_from_mask ((~ c1) & GET_MODE_MASK (GET_MODE (dest)), &len); - if (pos < 0 || pos + len > GET_MODE_BITSIZE (GET_MODE (dest)) - || GET_MODE_BITSIZE (GET_MODE (dest)) > HOST_BITS_PER_WIDE_INT - || (c1 & nonzero_bits (other, GET_MODE (dest))) != 0) - return x; - - assign = make_extraction (VOIDmode, dest, pos, NULL_RTX, len, 1, 1, 0); - if (assign == 0) - return x; - - /* The mode to use for the source is the mode of the assignment, or of - what is inside a possible STRICT_LOW_PART. */ - mode = (GET_CODE (assign) == STRICT_LOW_PART - ? GET_MODE (XEXP (assign, 0)) : GET_MODE (assign)); - - /* Shift OTHER right POS places and make it the source, restricting it - to the proper length and mode. */ - - src = force_to_mode (simplify_shift_const (NULL_RTX, LSHIFTRT, - GET_MODE (src), other, pos), - mode, - GET_MODE_BITSIZE (mode) >= HOST_BITS_PER_WIDE_INT - ? GET_MODE_MASK (mode) - : ((HOST_WIDE_INT) 1 << len) - 1, - dest, 0); - - return gen_rtx_combine (SET, VOIDmode, assign, src); -} - -/* See if X is of the form (+ (* a c) (* b c)) and convert to (* (+ a b) c) - if so. */ - -static rtx -apply_distributive_law (x) - rtx x; -{ - enum rtx_code code = GET_CODE (x); - rtx lhs, rhs, other; - rtx tem; - enum rtx_code inner_code; - - /* Distributivity is not true for floating point. - It can change the value. So don't do it. - -- rms and moshier@world.std.com. */ - if (FLOAT_MODE_P (GET_MODE (x))) - return x; - - /* The outer operation can only be one of the following: */ - if (code != IOR && code != AND && code != XOR - && code != PLUS && code != MINUS) - return x; - - lhs = XEXP (x, 0), rhs = XEXP (x, 1); - - /* If either operand is a primitive we can't do anything, so get out - fast. */ - if (GET_RTX_CLASS (GET_CODE (lhs)) == 'o' - || GET_RTX_CLASS (GET_CODE (rhs)) == 'o') - return x; - - lhs = expand_compound_operation (lhs); - rhs = expand_compound_operation (rhs); - inner_code = GET_CODE (lhs); - if (inner_code != GET_CODE (rhs)) - return x; - - /* See if the inner and outer operations distribute. */ - switch (inner_code) - { - case LSHIFTRT: - case ASHIFTRT: - case AND: - case IOR: - /* These all distribute except over PLUS. */ - if (code == PLUS || code == MINUS) - return x; - break; - - case MULT: - if (code != PLUS && code != MINUS) - return x; - break; - - case ASHIFT: - /* This is also a multiply, so it distributes over everything. */ - break; - - case SUBREG: - /* Non-paradoxical SUBREGs distributes over all operations, provided - the inner modes and word numbers are the same, this is an extraction - of a low-order part, we don't convert an fp operation to int or - vice versa, and we would not be converting a single-word - operation into a multi-word operation. The latter test is not - required, but it prevents generating unneeded multi-word operations. - Some of the previous tests are redundant given the latter test, but - are retained because they are required for correctness. - - We produce the result slightly differently in this case. */ - - if (GET_MODE (SUBREG_REG (lhs)) != GET_MODE (SUBREG_REG (rhs)) - || SUBREG_WORD (lhs) != SUBREG_WORD (rhs) - || ! subreg_lowpart_p (lhs) - || (GET_MODE_CLASS (GET_MODE (lhs)) - != GET_MODE_CLASS (GET_MODE (SUBREG_REG (lhs)))) - || (GET_MODE_SIZE (GET_MODE (lhs)) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (lhs)))) - || GET_MODE_SIZE (GET_MODE (SUBREG_REG (lhs))) > UNITS_PER_WORD) - return x; - - tem = gen_binary (code, GET_MODE (SUBREG_REG (lhs)), - SUBREG_REG (lhs), SUBREG_REG (rhs)); - return gen_lowpart_for_combine (GET_MODE (x), tem); - - default: - return x; - } - - /* Set LHS and RHS to the inner operands (A and B in the example - above) and set OTHER to the common operand (C in the example). - These is only one way to do this unless the inner operation is - commutative. */ - if (GET_RTX_CLASS (inner_code) == 'c' - && rtx_equal_p (XEXP (lhs, 0), XEXP (rhs, 0))) - other = XEXP (lhs, 0), lhs = XEXP (lhs, 1), rhs = XEXP (rhs, 1); - else if (GET_RTX_CLASS (inner_code) == 'c' - && rtx_equal_p (XEXP (lhs, 0), XEXP (rhs, 1))) - other = XEXP (lhs, 0), lhs = XEXP (lhs, 1), rhs = XEXP (rhs, 0); - else if (GET_RTX_CLASS (inner_code) == 'c' - && rtx_equal_p (XEXP (lhs, 1), XEXP (rhs, 0))) - other = XEXP (lhs, 1), lhs = XEXP (lhs, 0), rhs = XEXP (rhs, 1); - else if (rtx_equal_p (XEXP (lhs, 1), XEXP (rhs, 1))) - other = XEXP (lhs, 1), lhs = XEXP (lhs, 0), rhs = XEXP (rhs, 0); - else - return x; - - /* Form the new inner operation, seeing if it simplifies first. */ - tem = gen_binary (code, GET_MODE (x), lhs, rhs); - - /* There is one exception to the general way of distributing: - (a ^ b) | (a ^ c) -> (~a) & (b ^ c) */ - if (code == XOR && inner_code == IOR) - { - inner_code = AND; - other = gen_unary (NOT, GET_MODE (x), GET_MODE (x), other); - } - - /* We may be able to continuing distributing the result, so call - ourselves recursively on the inner operation before forming the - outer operation, which we return. */ - return gen_binary (inner_code, GET_MODE (x), - apply_distributive_law (tem), other); -} - -/* We have X, a logical `and' of VAROP with the constant CONSTOP, to be done - in MODE. - - Return an equivalent form, if different from X. Otherwise, return X. If - X is zero, we are to always construct the equivalent form. */ - -static rtx -simplify_and_const_int (x, mode, varop, constop) - rtx x; - enum machine_mode mode; - rtx varop; - unsigned HOST_WIDE_INT constop; -{ - unsigned HOST_WIDE_INT nonzero; - int width = GET_MODE_BITSIZE (mode); - int i; - - /* Simplify VAROP knowing that we will be only looking at some of the - bits in it. */ - varop = force_to_mode (varop, mode, constop, NULL_RTX, 0); - - /* If VAROP is a CLOBBER, we will fail so return it; if it is a - CONST_INT, we are done. */ - if (GET_CODE (varop) == CLOBBER || GET_CODE (varop) == CONST_INT) - return varop; - - /* See what bits may be nonzero in VAROP. Unlike the general case of - a call to nonzero_bits, here we don't care about bits outside - MODE. */ - - nonzero = nonzero_bits (varop, mode) & GET_MODE_MASK (mode); - - /* If this would be an entire word for the target, but is not for - the host, then sign-extend on the host so that the number will look - the same way on the host that it would on the target. - - For example, when building a 64 bit alpha hosted 32 bit sparc - targeted compiler, then we want the 32 bit unsigned value -1 to be - represented as a 64 bit value -1, and not as 0x00000000ffffffff. - The later confuses the sparc backend. */ - - if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width - && (nonzero & ((HOST_WIDE_INT) 1 << (width - 1)))) - nonzero |= ((HOST_WIDE_INT) (-1) << width); - - /* Turn off all bits in the constant that are known to already be zero. - Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS - which is tested below. */ - - constop &= nonzero; - - /* If we don't have any bits left, return zero. */ - if (constop == 0) - return const0_rtx; - - /* If VAROP is a NEG of something known to be zero or 1 and CONSTOP is - a power of two, we can replace this with a ASHIFT. */ - if (GET_CODE (varop) == NEG && nonzero_bits (XEXP (varop, 0), mode) == 1 - && (i = exact_log2 (constop)) >= 0) - return simplify_shift_const (NULL_RTX, ASHIFT, mode, XEXP (varop, 0), i); - - /* If VAROP is an IOR or XOR, apply the AND to both branches of the IOR - or XOR, then try to apply the distributive law. This may eliminate - operations if either branch can be simplified because of the AND. - It may also make some cases more complex, but those cases probably - won't match a pattern either with or without this. */ - - if (GET_CODE (varop) == IOR || GET_CODE (varop) == XOR) - return - gen_lowpart_for_combine - (mode, - apply_distributive_law - (gen_binary (GET_CODE (varop), GET_MODE (varop), - simplify_and_const_int (NULL_RTX, GET_MODE (varop), - XEXP (varop, 0), constop), - simplify_and_const_int (NULL_RTX, GET_MODE (varop), - XEXP (varop, 1), constop)))); - - /* Get VAROP in MODE. Try to get a SUBREG if not. Don't make a new SUBREG - if we already had one (just check for the simplest cases). */ - if (x && GET_CODE (XEXP (x, 0)) == SUBREG - && GET_MODE (XEXP (x, 0)) == mode - && SUBREG_REG (XEXP (x, 0)) == varop) - varop = XEXP (x, 0); - else - varop = gen_lowpart_for_combine (mode, varop); - - /* If we can't make the SUBREG, try to return what we were given. */ - if (GET_CODE (varop) == CLOBBER) - return x ? x : varop; - - /* If we are only masking insignificant bits, return VAROP. */ - if (constop == nonzero) - x = varop; - - /* Otherwise, return an AND. See how much, if any, of X we can use. */ - else if (x == 0 || GET_CODE (x) != AND || GET_MODE (x) != mode) - x = gen_binary (AND, mode, varop, GEN_INT (constop)); - - else - { - if (GET_CODE (XEXP (x, 1)) != CONST_INT - || (unsigned HOST_WIDE_INT) INTVAL (XEXP (x, 1)) != constop) - SUBST (XEXP (x, 1), GEN_INT (constop)); - - SUBST (XEXP (x, 0), varop); - } - - return x; -} - -/* We let num_sign_bit_copies recur into nonzero_bits as that is useful. - We don't let nonzero_bits recur into num_sign_bit_copies, because that - is less useful. We can't allow both, because that results in exponential - run time recursion. There is a nullstone testcase that triggered - this. This macro avoids accidental uses of num_sign_bit_copies. */ -#define num_sign_bit_copies() - -/* Given an expression, X, compute which bits in X can be non-zero. - We don't care about bits outside of those defined in MODE. - - For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is - a shift, AND, or zero_extract, we can do better. */ - -static unsigned HOST_WIDE_INT -nonzero_bits (x, mode) - rtx x; - enum machine_mode mode; -{ - unsigned HOST_WIDE_INT nonzero = GET_MODE_MASK (mode); - unsigned HOST_WIDE_INT inner_nz; - enum rtx_code code; - int mode_width = GET_MODE_BITSIZE (mode); - rtx tem; - - /* For floating-point values, assume all bits are needed. */ - if (FLOAT_MODE_P (GET_MODE (x)) || FLOAT_MODE_P (mode)) - return nonzero; - - /* If X is wider than MODE, use its mode instead. */ - if (GET_MODE_BITSIZE (GET_MODE (x)) > mode_width) - { - mode = GET_MODE (x); - nonzero = GET_MODE_MASK (mode); - mode_width = GET_MODE_BITSIZE (mode); - } - - if (mode_width > HOST_BITS_PER_WIDE_INT) - /* Our only callers in this case look for single bit values. So - just return the mode mask. Those tests will then be false. */ - return nonzero; - -#ifndef WORD_REGISTER_OPERATIONS - /* If MODE is wider than X, but both are a single word for both the host - and target machines, we can compute this from which bits of the - object might be nonzero in its own mode, taking into account the fact - that on many CISC machines, accessing an object in a wider mode - causes the high-order bits to become undefined. So they are - not known to be zero. */ - - if (GET_MODE (x) != VOIDmode && GET_MODE (x) != mode - && GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD - && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT - && GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (GET_MODE (x))) - { - nonzero &= nonzero_bits (x, GET_MODE (x)); - nonzero |= GET_MODE_MASK (mode) & ~ GET_MODE_MASK (GET_MODE (x)); - return nonzero; - } -#endif - - code = GET_CODE (x); - switch (code) - { - case REG: -#ifdef POINTERS_EXTEND_UNSIGNED - /* If pointers extend unsigned and this is a pointer in Pmode, say that - all the bits above ptr_mode are known to be zero. */ - if (POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode - && REGNO_POINTER_FLAG (REGNO (x))) - nonzero &= GET_MODE_MASK (ptr_mode); -#endif - -#ifdef STACK_BOUNDARY - /* If this is the stack pointer, we may know something about its - alignment. If PUSH_ROUNDING is defined, it is possible for the - stack to be momentarily aligned only to that amount, so we pick - the least alignment. */ - - /* We can't check for arg_pointer_rtx here, because it is not - guaranteed to have as much alignment as the stack pointer. - In particular, in the Irix6 n64 ABI, the stack has 128 bit - alignment but the argument pointer has only 64 bit alignment. */ - - if ((x == frame_pointer_rtx - || x == stack_pointer_rtx - || x == hard_frame_pointer_rtx - || (REGNO (x) >= FIRST_VIRTUAL_REGISTER - && REGNO (x) <= LAST_VIRTUAL_REGISTER)) -#ifdef STACK_BIAS - && !STACK_BIAS -#endif - ) - { - int sp_alignment = STACK_BOUNDARY / BITS_PER_UNIT; - -#ifdef PUSH_ROUNDING - if (REGNO (x) == STACK_POINTER_REGNUM) - sp_alignment = MIN (PUSH_ROUNDING (1), sp_alignment); -#endif - - /* We must return here, otherwise we may get a worse result from - one of the choices below. There is nothing useful below as - far as the stack pointer is concerned. */ - return nonzero &= ~ (sp_alignment - 1); - } -#endif - - /* If X is a register whose nonzero bits value is current, use it. - Otherwise, if X is a register whose value we can find, use that - value. Otherwise, use the previously-computed global nonzero bits - for this register. */ - - if (reg_last_set_value[REGNO (x)] != 0 - && reg_last_set_mode[REGNO (x)] == mode - && (REG_N_SETS (REGNO (x)) == 1 - || reg_last_set_label[REGNO (x)] == label_tick) - && INSN_CUID (reg_last_set[REGNO (x)]) < subst_low_cuid) - return reg_last_set_nonzero_bits[REGNO (x)]; - - tem = get_last_value (x); - - if (tem) - { -#ifdef SHORT_IMMEDIATES_SIGN_EXTEND - /* If X is narrower than MODE and TEM is a non-negative - constant that would appear negative in the mode of X, - sign-extend it for use in reg_nonzero_bits because some - machines (maybe most) will actually do the sign-extension - and this is the conservative approach. - - ??? For 2.5, try to tighten up the MD files in this regard - instead of this kludge. */ - - if (GET_MODE_BITSIZE (GET_MODE (x)) < mode_width - && GET_CODE (tem) == CONST_INT - && INTVAL (tem) > 0 - && 0 != (INTVAL (tem) - & ((HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (GET_MODE (x)) - 1)))) - tem = GEN_INT (INTVAL (tem) - | ((HOST_WIDE_INT) (-1) - << GET_MODE_BITSIZE (GET_MODE (x)))); -#endif - return nonzero_bits (tem, mode); - } - else if (nonzero_sign_valid && reg_nonzero_bits[REGNO (x)]) - return reg_nonzero_bits[REGNO (x)] & nonzero; - else - return nonzero; - - case CONST_INT: -#ifdef SHORT_IMMEDIATES_SIGN_EXTEND - /* If X is negative in MODE, sign-extend the value. */ - if (INTVAL (x) > 0 && mode_width < BITS_PER_WORD - && 0 != (INTVAL (x) & ((HOST_WIDE_INT) 1 << (mode_width - 1)))) - return (INTVAL (x) | ((HOST_WIDE_INT) (-1) << mode_width)); -#endif - - return INTVAL (x); - - case MEM: -#ifdef LOAD_EXTEND_OP - /* In many, if not most, RISC machines, reading a byte from memory - zeros the rest of the register. Noticing that fact saves a lot - of extra zero-extends. */ - if (LOAD_EXTEND_OP (GET_MODE (x)) == ZERO_EXTEND) - nonzero &= GET_MODE_MASK (GET_MODE (x)); -#endif - break; - - case EQ: case NE: - case GT: case GTU: - case LT: case LTU: - case GE: case GEU: - case LE: case LEU: - - /* If this produces an integer result, we know which bits are set. - Code here used to clear bits outside the mode of X, but that is - now done above. */ - - if (GET_MODE_CLASS (mode) == MODE_INT - && mode_width <= HOST_BITS_PER_WIDE_INT) - nonzero = STORE_FLAG_VALUE; - break; - - case NEG: -#if 0 - /* Disabled to avoid exponential mutual recursion between nonzero_bits - and num_sign_bit_copies. */ - if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x)) - == GET_MODE_BITSIZE (GET_MODE (x))) - nonzero = 1; -#endif - - if (GET_MODE_SIZE (GET_MODE (x)) < mode_width) - nonzero |= (GET_MODE_MASK (mode) & ~ GET_MODE_MASK (GET_MODE (x))); - break; - - case ABS: -#if 0 - /* Disabled to avoid exponential mutual recursion between nonzero_bits - and num_sign_bit_copies. */ - if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x)) - == GET_MODE_BITSIZE (GET_MODE (x))) - nonzero = 1; -#endif - break; - - case TRUNCATE: - nonzero &= (nonzero_bits (XEXP (x, 0), mode) & GET_MODE_MASK (mode)); - break; - - case ZERO_EXTEND: - nonzero &= nonzero_bits (XEXP (x, 0), mode); - if (GET_MODE (XEXP (x, 0)) != VOIDmode) - nonzero &= GET_MODE_MASK (GET_MODE (XEXP (x, 0))); - break; - - case SIGN_EXTEND: - /* If the sign bit is known clear, this is the same as ZERO_EXTEND. - Otherwise, show all the bits in the outer mode but not the inner - may be non-zero. */ - inner_nz = nonzero_bits (XEXP (x, 0), mode); - if (GET_MODE (XEXP (x, 0)) != VOIDmode) - { - inner_nz &= GET_MODE_MASK (GET_MODE (XEXP (x, 0))); - if (inner_nz - & (((HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - 1)))) - inner_nz |= (GET_MODE_MASK (mode) - & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))); - } - - nonzero &= inner_nz; - break; - - case AND: - nonzero &= (nonzero_bits (XEXP (x, 0), mode) - & nonzero_bits (XEXP (x, 1), mode)); - break; - - case XOR: case IOR: - case UMIN: case UMAX: case SMIN: case SMAX: - nonzero &= (nonzero_bits (XEXP (x, 0), mode) - | nonzero_bits (XEXP (x, 1), mode)); - break; - - case PLUS: case MINUS: - case MULT: - case DIV: case UDIV: - case MOD: case UMOD: - /* We can apply the rules of arithmetic to compute the number of - high- and low-order zero bits of these operations. We start by - computing the width (position of the highest-order non-zero bit) - and the number of low-order zero bits for each value. */ - { - unsigned HOST_WIDE_INT nz0 = nonzero_bits (XEXP (x, 0), mode); - unsigned HOST_WIDE_INT nz1 = nonzero_bits (XEXP (x, 1), mode); - int width0 = floor_log2 (nz0) + 1; - int width1 = floor_log2 (nz1) + 1; - int low0 = floor_log2 (nz0 & -nz0); - int low1 = floor_log2 (nz1 & -nz1); - HOST_WIDE_INT op0_maybe_minusp - = (nz0 & ((HOST_WIDE_INT) 1 << (mode_width - 1))); - HOST_WIDE_INT op1_maybe_minusp - = (nz1 & ((HOST_WIDE_INT) 1 << (mode_width - 1))); - int result_width = mode_width; - int result_low = 0; - - switch (code) - { - case PLUS: -#ifdef STACK_BIAS - if (STACK_BIAS - && (XEXP (x, 0) == stack_pointer_rtx - || XEXP (x, 0) == frame_pointer_rtx) - && GET_CODE (XEXP (x, 1)) == CONST_INT) - { - int sp_alignment = STACK_BOUNDARY / BITS_PER_UNIT; - - nz0 = (GET_MODE_MASK (mode) & ~ (sp_alignment - 1)); - nz1 = INTVAL (XEXP (x, 1)) - STACK_BIAS; - width0 = floor_log2 (nz0) + 1; - width1 = floor_log2 (nz1) + 1; - low0 = floor_log2 (nz0 & -nz0); - low1 = floor_log2 (nz1 & -nz1); - } -#endif - result_width = MAX (width0, width1) + 1; - result_low = MIN (low0, low1); - break; - case MINUS: - result_low = MIN (low0, low1); - break; - case MULT: - result_width = width0 + width1; - result_low = low0 + low1; - break; - case DIV: - if (! op0_maybe_minusp && ! op1_maybe_minusp) - result_width = width0; - break; - case UDIV: - result_width = width0; - break; - case MOD: - if (! op0_maybe_minusp && ! op1_maybe_minusp) - result_width = MIN (width0, width1); - result_low = MIN (low0, low1); - break; - case UMOD: - result_width = MIN (width0, width1); - result_low = MIN (low0, low1); - break; - default: - abort (); - } - - if (result_width < mode_width) - nonzero &= ((HOST_WIDE_INT) 1 << result_width) - 1; - - if (result_low > 0) - nonzero &= ~ (((HOST_WIDE_INT) 1 << result_low) - 1); - } - break; - - case ZERO_EXTRACT: - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT) - nonzero &= ((HOST_WIDE_INT) 1 << INTVAL (XEXP (x, 1))) - 1; - break; - - case SUBREG: - /* If this is a SUBREG formed for a promoted variable that has - been zero-extended, we know that at least the high-order bits - are zero, though others might be too. */ - - if (SUBREG_PROMOTED_VAR_P (x) && SUBREG_PROMOTED_UNSIGNED_P (x)) - nonzero = (GET_MODE_MASK (GET_MODE (x)) - & nonzero_bits (SUBREG_REG (x), GET_MODE (x))); - - /* If the inner mode is a single word for both the host and target - machines, we can compute this from which bits of the inner - object might be nonzero. */ - if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) <= BITS_PER_WORD - && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) - <= HOST_BITS_PER_WIDE_INT)) - { - nonzero &= nonzero_bits (SUBREG_REG (x), mode); - -#if defined (WORD_REGISTER_OPERATIONS) && defined (LOAD_EXTEND_OP) - /* If this is a typical RISC machine, we only have to worry - about the way loads are extended. */ - if (LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND - ? (nonzero - & (1L << (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) - 1))) - : LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) != ZERO_EXTEND) -#endif - { - /* On many CISC machines, accessing an object in a wider mode - causes the high-order bits to become undefined. So they are - not known to be zero. */ - if (GET_MODE_SIZE (GET_MODE (x)) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) - nonzero |= (GET_MODE_MASK (GET_MODE (x)) - & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x)))); - } - } - break; - - case ASHIFTRT: - case LSHIFTRT: - case ASHIFT: - case ROTATE: - /* The nonzero bits are in two classes: any bits within MODE - that aren't in GET_MODE (x) are always significant. The rest of the - nonzero bits are those that are significant in the operand of - the shift when shifted the appropriate number of bits. This - shows that high-order bits are cleared by the right shift and - low-order bits by left shifts. */ - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) >= 0 - && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT) - { - enum machine_mode inner_mode = GET_MODE (x); - int width = GET_MODE_BITSIZE (inner_mode); - int count = INTVAL (XEXP (x, 1)); - unsigned HOST_WIDE_INT mode_mask = GET_MODE_MASK (inner_mode); - unsigned HOST_WIDE_INT op_nonzero = nonzero_bits (XEXP (x, 0), mode); - unsigned HOST_WIDE_INT inner = op_nonzero & mode_mask; - unsigned HOST_WIDE_INT outer = 0; - - if (mode_width > width) - outer = (op_nonzero & nonzero & ~ mode_mask); - - if (code == LSHIFTRT) - inner >>= count; - else if (code == ASHIFTRT) - { - inner >>= count; - - /* If the sign bit may have been nonzero before the shift, we - need to mark all the places it could have been copied to - by the shift as possibly nonzero. */ - if (inner & ((HOST_WIDE_INT) 1 << (width - 1 - count))) - inner |= (((HOST_WIDE_INT) 1 << count) - 1) << (width - count); - } - else if (code == ASHIFT) - inner <<= count; - else - inner = ((inner << (count % width) - | (inner >> (width - (count % width)))) & mode_mask); - - nonzero &= (outer | inner); - } - break; - - case FFS: - /* This is at most the number of bits in the mode. */ - nonzero = ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width) + 1)) - 1; - break; - - case IF_THEN_ELSE: - nonzero &= (nonzero_bits (XEXP (x, 1), mode) - | nonzero_bits (XEXP (x, 2), mode)); - break; - - default: - break; - } - - return nonzero; -} - -/* See the macro definition above. */ -#undef num_sign_bit_copies - -/* Return the number of bits at the high-order end of X that are known to - be equal to the sign bit. X will be used in mode MODE; if MODE is - VOIDmode, X will be used in its own mode. The returned value will always - be between 1 and the number of bits in MODE. */ - -static int -num_sign_bit_copies (x, mode) - rtx x; - enum machine_mode mode; -{ - enum rtx_code code = GET_CODE (x); - int bitwidth; - int num0, num1, result; - unsigned HOST_WIDE_INT nonzero; - rtx tem; - - /* If we weren't given a mode, use the mode of X. If the mode is still - VOIDmode, we don't know anything. Likewise if one of the modes is - floating-point. */ - - if (mode == VOIDmode) - mode = GET_MODE (x); - - if (mode == VOIDmode || FLOAT_MODE_P (mode) || FLOAT_MODE_P (GET_MODE (x))) - return 1; - - bitwidth = GET_MODE_BITSIZE (mode); - - /* For a smaller object, just ignore the high bits. */ - if (bitwidth < GET_MODE_BITSIZE (GET_MODE (x))) - return MAX (1, (num_sign_bit_copies (x, GET_MODE (x)) - - (GET_MODE_BITSIZE (GET_MODE (x)) - bitwidth))); - - if (GET_MODE (x) != VOIDmode && bitwidth > GET_MODE_BITSIZE (GET_MODE (x))) - { -#ifndef WORD_REGISTER_OPERATIONS - /* If this machine does not do all register operations on the entire - register and MODE is wider than the mode of X, we can say nothing - at all about the high-order bits. */ - return 1; -#else - /* Likewise on machines that do, if the mode of the object is smaller - than a word and loads of that size don't sign extend, we can say - nothing about the high order bits. */ - if (GET_MODE_BITSIZE (GET_MODE (x)) < BITS_PER_WORD -#ifdef LOAD_EXTEND_OP - && LOAD_EXTEND_OP (GET_MODE (x)) != SIGN_EXTEND -#endif - ) - return 1; -#endif - } - - switch (code) - { - case REG: - -#ifdef POINTERS_EXTEND_UNSIGNED - /* If pointers extend signed and this is a pointer in Pmode, say that - all the bits above ptr_mode are known to be sign bit copies. */ - if (! POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode && mode == Pmode - && REGNO_POINTER_FLAG (REGNO (x))) - return GET_MODE_BITSIZE (Pmode) - GET_MODE_BITSIZE (ptr_mode) + 1; -#endif - - if (reg_last_set_value[REGNO (x)] != 0 - && reg_last_set_mode[REGNO (x)] == mode - && (REG_N_SETS (REGNO (x)) == 1 - || reg_last_set_label[REGNO (x)] == label_tick) - && INSN_CUID (reg_last_set[REGNO (x)]) < subst_low_cuid) - return reg_last_set_sign_bit_copies[REGNO (x)]; - - tem = get_last_value (x); - if (tem != 0) - return num_sign_bit_copies (tem, mode); - - if (nonzero_sign_valid && reg_sign_bit_copies[REGNO (x)] != 0) - return reg_sign_bit_copies[REGNO (x)]; - break; - - case MEM: -#ifdef LOAD_EXTEND_OP - /* Some RISC machines sign-extend all loads of smaller than a word. */ - if (LOAD_EXTEND_OP (GET_MODE (x)) == SIGN_EXTEND) - return MAX (1, bitwidth - GET_MODE_BITSIZE (GET_MODE (x)) + 1); -#endif - break; - - case CONST_INT: - /* If the constant is negative, take its 1's complement and remask. - Then see how many zero bits we have. */ - nonzero = INTVAL (x) & GET_MODE_MASK (mode); - if (bitwidth <= HOST_BITS_PER_WIDE_INT - && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0) - nonzero = (~ nonzero) & GET_MODE_MASK (mode); - - return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1); - - case SUBREG: - /* If this is a SUBREG for a promoted object that is sign-extended - and we are looking at it in a wider mode, we know that at least the - high-order bits are known to be sign bit copies. */ - - if (SUBREG_PROMOTED_VAR_P (x) && ! SUBREG_PROMOTED_UNSIGNED_P (x)) - return MAX (bitwidth - GET_MODE_BITSIZE (GET_MODE (x)) + 1, - num_sign_bit_copies (SUBREG_REG (x), mode)); - - /* For a smaller object, just ignore the high bits. */ - if (bitwidth <= GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))) - { - num0 = num_sign_bit_copies (SUBREG_REG (x), VOIDmode); - return MAX (1, (num0 - - (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) - - bitwidth))); - } - -#ifdef WORD_REGISTER_OPERATIONS -#ifdef LOAD_EXTEND_OP - /* For paradoxical SUBREGs on machines where all register operations - affect the entire register, just look inside. Note that we are - passing MODE to the recursive call, so the number of sign bit copies - will remain relative to that mode, not the inner mode. */ - - /* This works only if loads sign extend. Otherwise, if we get a - reload for the inner part, it may be loaded from the stack, and - then we lose all sign bit copies that existed before the store - to the stack. */ - - if ((GET_MODE_SIZE (GET_MODE (x)) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) - && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND) - return num_sign_bit_copies (SUBREG_REG (x), mode); -#endif -#endif - break; - - case SIGN_EXTRACT: - if (GET_CODE (XEXP (x, 1)) == CONST_INT) - return MAX (1, bitwidth - INTVAL (XEXP (x, 1))); - break; - - case SIGN_EXTEND: - return (bitwidth - GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - + num_sign_bit_copies (XEXP (x, 0), VOIDmode)); - - case TRUNCATE: - /* For a smaller object, just ignore the high bits. */ - num0 = num_sign_bit_copies (XEXP (x, 0), VOIDmode); - return MAX (1, (num0 - (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - - bitwidth))); - - case NOT: - return num_sign_bit_copies (XEXP (x, 0), mode); - - case ROTATE: case ROTATERT: - /* If we are rotating left by a number of bits less than the number - of sign bit copies, we can just subtract that amount from the - number. */ - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) >= 0 && INTVAL (XEXP (x, 1)) < bitwidth) - { - num0 = num_sign_bit_copies (XEXP (x, 0), mode); - return MAX (1, num0 - (code == ROTATE ? INTVAL (XEXP (x, 1)) - : bitwidth - INTVAL (XEXP (x, 1)))); - } - break; - - case NEG: - /* In general, this subtracts one sign bit copy. But if the value - is known to be positive, the number of sign bit copies is the - same as that of the input. Finally, if the input has just one bit - that might be nonzero, all the bits are copies of the sign bit. */ - num0 = num_sign_bit_copies (XEXP (x, 0), mode); - if (bitwidth > HOST_BITS_PER_WIDE_INT) - return num0 > 1 ? num0 - 1 : 1; - - nonzero = nonzero_bits (XEXP (x, 0), mode); - if (nonzero == 1) - return bitwidth; - - if (num0 > 1 - && (((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero)) - num0--; - - return num0; - - case IOR: case AND: case XOR: - case SMIN: case SMAX: case UMIN: case UMAX: - /* Logical operations will preserve the number of sign-bit copies. - MIN and MAX operations always return one of the operands. */ - num0 = num_sign_bit_copies (XEXP (x, 0), mode); - num1 = num_sign_bit_copies (XEXP (x, 1), mode); - return MIN (num0, num1); - - case PLUS: case MINUS: - /* For addition and subtraction, we can have a 1-bit carry. However, - if we are subtracting 1 from a positive number, there will not - be such a carry. Furthermore, if the positive number is known to - be 0 or 1, we know the result is either -1 or 0. */ - - if (code == PLUS && XEXP (x, 1) == constm1_rtx - && bitwidth <= HOST_BITS_PER_WIDE_INT) - { - nonzero = nonzero_bits (XEXP (x, 0), mode); - if ((((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero) == 0) - return (nonzero == 1 || nonzero == 0 ? bitwidth - : bitwidth - floor_log2 (nonzero) - 1); - } - - num0 = num_sign_bit_copies (XEXP (x, 0), mode); - num1 = num_sign_bit_copies (XEXP (x, 1), mode); - return MAX (1, MIN (num0, num1) - 1); - - case MULT: - /* The number of bits of the product is the sum of the number of - bits of both terms. However, unless one of the terms if known - to be positive, we must allow for an additional bit since negating - a negative number can remove one sign bit copy. */ - - num0 = num_sign_bit_copies (XEXP (x, 0), mode); - num1 = num_sign_bit_copies (XEXP (x, 1), mode); - - result = bitwidth - (bitwidth - num0) - (bitwidth - num1); - if (result > 0 - && (bitwidth > HOST_BITS_PER_WIDE_INT - || (((nonzero_bits (XEXP (x, 0), mode) - & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0) - && ((nonzero_bits (XEXP (x, 1), mode) - & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)))) - result--; - - return MAX (1, result); - - case UDIV: - /* The result must be <= the first operand. If the first operand - has the high bit set, we know nothing about the number of sign - bit copies. */ - if (bitwidth > HOST_BITS_PER_WIDE_INT) - return 1; - else if ((nonzero_bits (XEXP (x, 0), mode) - & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0) - return 1; - else - return num_sign_bit_copies (XEXP (x, 0), mode); - - case UMOD: - /* The result must be <= the scond operand. */ - return num_sign_bit_copies (XEXP (x, 1), mode); - - case DIV: - /* Similar to unsigned division, except that we have to worry about - the case where the divisor is negative, in which case we have - to add 1. */ - result = num_sign_bit_copies (XEXP (x, 0), mode); - if (result > 1 - && (bitwidth > HOST_BITS_PER_WIDE_INT - || (nonzero_bits (XEXP (x, 1), mode) - & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)) - result--; - - return result; - - case MOD: - result = num_sign_bit_copies (XEXP (x, 1), mode); - if (result > 1 - && (bitwidth > HOST_BITS_PER_WIDE_INT - || (nonzero_bits (XEXP (x, 1), mode) - & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)) - result--; - - return result; - - case ASHIFTRT: - /* Shifts by a constant add to the number of bits equal to the - sign bit. */ - num0 = num_sign_bit_copies (XEXP (x, 0), mode); - if (GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) > 0) - num0 = MIN (bitwidth, num0 + INTVAL (XEXP (x, 1))); - - return num0; - - case ASHIFT: - /* Left shifts destroy copies. */ - if (GET_CODE (XEXP (x, 1)) != CONST_INT - || INTVAL (XEXP (x, 1)) < 0 - || INTVAL (XEXP (x, 1)) >= bitwidth) - return 1; - - num0 = num_sign_bit_copies (XEXP (x, 0), mode); - return MAX (1, num0 - INTVAL (XEXP (x, 1))); - - case IF_THEN_ELSE: - num0 = num_sign_bit_copies (XEXP (x, 1), mode); - num1 = num_sign_bit_copies (XEXP (x, 2), mode); - return MIN (num0, num1); - - case EQ: case NE: case GE: case GT: case LE: case LT: - case GEU: case GTU: case LEU: case LTU: - if (STORE_FLAG_VALUE == -1) - return bitwidth; - break; - - default: - break; - } - - /* If we haven't been able to figure it out by one of the above rules, - see if some of the high-order bits are known to be zero. If so, - count those bits and return one less than that amount. If we can't - safely compute the mask for this mode, always return BITWIDTH. */ - - if (bitwidth > HOST_BITS_PER_WIDE_INT) - return 1; - - nonzero = nonzero_bits (x, mode); - return (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1)) - ? 1 : bitwidth - floor_log2 (nonzero) - 1); -} - -/* Return the number of "extended" bits there are in X, when interpreted - as a quantity in MODE whose signedness is indicated by UNSIGNEDP. For - unsigned quantities, this is the number of high-order zero bits. - For signed quantities, this is the number of copies of the sign bit - minus 1. In both case, this function returns the number of "spare" - bits. For example, if two quantities for which this function returns - at least 1 are added, the addition is known not to overflow. - - This function will always return 0 unless called during combine, which - implies that it must be called from a define_split. */ - -int -extended_count (x, mode, unsignedp) - rtx x; - enum machine_mode mode; - int unsignedp; -{ - if (nonzero_sign_valid == 0) - return 0; - - return (unsignedp - ? (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && (GET_MODE_BITSIZE (mode) - 1 - - floor_log2 (nonzero_bits (x, mode)))) - : num_sign_bit_copies (x, mode) - 1); -} - -/* This function is called from `simplify_shift_const' to merge two - outer operations. Specifically, we have already found that we need - to perform operation *POP0 with constant *PCONST0 at the outermost - position. We would now like to also perform OP1 with constant CONST1 - (with *POP0 being done last). - - Return 1 if we can do the operation and update *POP0 and *PCONST0 with - the resulting operation. *PCOMP_P is set to 1 if we would need to - complement the innermost operand, otherwise it is unchanged. - - MODE is the mode in which the operation will be done. No bits outside - the width of this mode matter. It is assumed that the width of this mode - is smaller than or equal to HOST_BITS_PER_WIDE_INT. - - If *POP0 or OP1 are NIL, it means no operation is required. Only NEG, PLUS, - IOR, XOR, and AND are supported. We may set *POP0 to SET if the proper - result is simply *PCONST0. - - If the resulting operation cannot be expressed as one operation, we - return 0 and do not change *POP0, *PCONST0, and *PCOMP_P. */ - -static int -merge_outer_ops (pop0, pconst0, op1, const1, mode, pcomp_p) - enum rtx_code *pop0; - HOST_WIDE_INT *pconst0; - enum rtx_code op1; - HOST_WIDE_INT const1; - enum machine_mode mode; - int *pcomp_p; -{ - enum rtx_code op0 = *pop0; - HOST_WIDE_INT const0 = *pconst0; - int width = GET_MODE_BITSIZE (mode); - - const0 &= GET_MODE_MASK (mode); - const1 &= GET_MODE_MASK (mode); - - /* If OP0 is an AND, clear unimportant bits in CONST1. */ - if (op0 == AND) - const1 &= const0; - - /* If OP0 or OP1 is NIL, this is easy. Similarly if they are the same or - if OP0 is SET. */ - - if (op1 == NIL || op0 == SET) - return 1; - - else if (op0 == NIL) - op0 = op1, const0 = const1; - - else if (op0 == op1) - { - switch (op0) - { - case AND: - const0 &= const1; - break; - case IOR: - const0 |= const1; - break; - case XOR: - const0 ^= const1; - break; - case PLUS: - const0 += const1; - break; - case NEG: - op0 = NIL; - break; - default: - break; - } - } - - /* Otherwise, if either is a PLUS or NEG, we can't do anything. */ - else if (op0 == PLUS || op1 == PLUS || op0 == NEG || op1 == NEG) - return 0; - - /* If the two constants aren't the same, we can't do anything. The - remaining six cases can all be done. */ - else if (const0 != const1) - return 0; - - else - switch (op0) - { - case IOR: - if (op1 == AND) - /* (a & b) | b == b */ - op0 = SET; - else /* op1 == XOR */ - /* (a ^ b) | b == a | b */ - {;} - break; - - case XOR: - if (op1 == AND) - /* (a & b) ^ b == (~a) & b */ - op0 = AND, *pcomp_p = 1; - else /* op1 == IOR */ - /* (a | b) ^ b == a & ~b */ - op0 = AND, *pconst0 = ~ const0; - break; - - case AND: - if (op1 == IOR) - /* (a | b) & b == b */ - op0 = SET; - else /* op1 == XOR */ - /* (a ^ b) & b) == (~a) & b */ - *pcomp_p = 1; - break; - default: - break; - } - - /* Check for NO-OP cases. */ - const0 &= GET_MODE_MASK (mode); - if (const0 == 0 - && (op0 == IOR || op0 == XOR || op0 == PLUS)) - op0 = NIL; - else if (const0 == 0 && op0 == AND) - op0 = SET; - else if ((unsigned HOST_WIDE_INT) const0 == GET_MODE_MASK (mode) - && op0 == AND) - op0 = NIL; - - /* If this would be an entire word for the target, but is not for - the host, then sign-extend on the host so that the number will look - the same way on the host that it would on the target. - - For example, when building a 64 bit alpha hosted 32 bit sparc - targeted compiler, then we want the 32 bit unsigned value -1 to be - represented as a 64 bit value -1, and not as 0x00000000ffffffff. - The later confuses the sparc backend. */ - - if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width - && (const0 & ((HOST_WIDE_INT) 1 << (width - 1)))) - const0 |= ((HOST_WIDE_INT) (-1) << width); - - *pop0 = op0; - *pconst0 = const0; - - return 1; -} - -/* Simplify a shift of VAROP by COUNT bits. CODE says what kind of shift. - The result of the shift is RESULT_MODE. X, if non-zero, is an expression - that we started with. - - The shift is normally computed in the widest mode we find in VAROP, as - long as it isn't a different number of words than RESULT_MODE. Exceptions - are ASHIFTRT and ROTATE, which are always done in their original mode, */ - -static rtx -simplify_shift_const (x, code, result_mode, varop, count) - rtx x; - enum rtx_code code; - enum machine_mode result_mode; - rtx varop; - int count; -{ - enum rtx_code orig_code = code; - int orig_count = count; - enum machine_mode mode = result_mode; - enum machine_mode shift_mode, tmode; - int mode_words - = (GET_MODE_SIZE (mode) + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD; - /* We form (outer_op (code varop count) (outer_const)). */ - enum rtx_code outer_op = NIL; - HOST_WIDE_INT outer_const = 0; - rtx const_rtx; - int complement_p = 0; - rtx new; - - /* If we were given an invalid count, don't do anything except exactly - what was requested. */ - - if (count < 0 || count > GET_MODE_BITSIZE (mode)) - { - if (x) - return x; - - return gen_rtx_fmt_ee (code, mode, varop, GEN_INT (count)); - } - - /* Unless one of the branches of the `if' in this loop does a `continue', - we will `break' the loop after the `if'. */ - - while (count != 0) - { - /* If we have an operand of (clobber (const_int 0)), just return that - value. */ - if (GET_CODE (varop) == CLOBBER) - return varop; - - /* If we discovered we had to complement VAROP, leave. Making a NOT - here would cause an infinite loop. */ - if (complement_p) - break; - - /* Convert ROTATERT to ROTATE. */ - if (code == ROTATERT) - code = ROTATE, count = GET_MODE_BITSIZE (result_mode) - count; - - /* We need to determine what mode we will do the shift in. If the - shift is a right shift or a ROTATE, we must always do it in the mode - it was originally done in. Otherwise, we can do it in MODE, the - widest mode encountered. */ - shift_mode - = (code == ASHIFTRT || code == LSHIFTRT || code == ROTATE - ? result_mode : mode); - - /* Handle cases where the count is greater than the size of the mode - minus 1. For ASHIFT, use the size minus one as the count (this can - occur when simplifying (lshiftrt (ashiftrt ..))). For rotates, - take the count modulo the size. For other shifts, the result is - zero. - - Since these shifts are being produced by the compiler by combining - multiple operations, each of which are defined, we know what the - result is supposed to be. */ - - if (count > GET_MODE_BITSIZE (shift_mode) - 1) - { - if (code == ASHIFTRT) - count = GET_MODE_BITSIZE (shift_mode) - 1; - else if (code == ROTATE || code == ROTATERT) - count %= GET_MODE_BITSIZE (shift_mode); - else - { - /* We can't simply return zero because there may be an - outer op. */ - varop = const0_rtx; - count = 0; - break; - } - } - - /* Negative counts are invalid and should not have been made (a - programmer-specified negative count should have been handled - above). */ - else if (count < 0) - abort (); - - /* An arithmetic right shift of a quantity known to be -1 or 0 - is a no-op. */ - if (code == ASHIFTRT - && (num_sign_bit_copies (varop, shift_mode) - == GET_MODE_BITSIZE (shift_mode))) - { - count = 0; - break; - } - - /* If we are doing an arithmetic right shift and discarding all but - the sign bit copies, this is equivalent to doing a shift by the - bitsize minus one. Convert it into that shift because it will often - allow other simplifications. */ - - if (code == ASHIFTRT - && (count + num_sign_bit_copies (varop, shift_mode) - >= GET_MODE_BITSIZE (shift_mode))) - count = GET_MODE_BITSIZE (shift_mode) - 1; - - /* We simplify the tests below and elsewhere by converting - ASHIFTRT to LSHIFTRT if we know the sign bit is clear. - `make_compound_operation' will convert it to a ASHIFTRT for - those machines (such as Vax) that don't have a LSHIFTRT. */ - if (GET_MODE_BITSIZE (shift_mode) <= HOST_BITS_PER_WIDE_INT - && code == ASHIFTRT - && ((nonzero_bits (varop, shift_mode) - & ((HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (shift_mode) - 1))) - == 0)) - code = LSHIFTRT; - - switch (GET_CODE (varop)) - { - case SIGN_EXTEND: - case ZERO_EXTEND: - case SIGN_EXTRACT: - case ZERO_EXTRACT: - new = expand_compound_operation (varop); - if (new != varop) - { - varop = new; - continue; - } - break; - - case MEM: - /* If we have (xshiftrt (mem ...) C) and C is MODE_WIDTH - minus the width of a smaller mode, we can do this with a - SIGN_EXTEND or ZERO_EXTEND from the narrower memory location. */ - if ((code == ASHIFTRT || code == LSHIFTRT) - && ! mode_dependent_address_p (XEXP (varop, 0)) - && ! MEM_VOLATILE_P (varop) - && (tmode = mode_for_size (GET_MODE_BITSIZE (mode) - count, - MODE_INT, 1)) != BLKmode) - { - if (BYTES_BIG_ENDIAN) - new = gen_rtx_MEM (tmode, XEXP (varop, 0)); - else - new = gen_rtx_MEM (tmode, - plus_constant (XEXP (varop, 0), - count / BITS_PER_UNIT)); - RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (varop); - MEM_COPY_ATTRIBUTES (new, varop); - varop = gen_rtx_combine (code == ASHIFTRT ? SIGN_EXTEND - : ZERO_EXTEND, mode, new); - count = 0; - continue; - } - break; - - case USE: - /* Similar to the case above, except that we can only do this if - the resulting mode is the same as that of the underlying - MEM and adjust the address depending on the *bits* endianness - because of the way that bit-field extract insns are defined. */ - if ((code == ASHIFTRT || code == LSHIFTRT) - && (tmode = mode_for_size (GET_MODE_BITSIZE (mode) - count, - MODE_INT, 1)) != BLKmode - && tmode == GET_MODE (XEXP (varop, 0))) - { - if (BITS_BIG_ENDIAN) - new = XEXP (varop, 0); - else - { - new = copy_rtx (XEXP (varop, 0)); - SUBST (XEXP (new, 0), - plus_constant (XEXP (new, 0), - count / BITS_PER_UNIT)); - } - - varop = gen_rtx_combine (code == ASHIFTRT ? SIGN_EXTEND - : ZERO_EXTEND, mode, new); - count = 0; - continue; - } - break; - - case SUBREG: - /* If VAROP is a SUBREG, strip it as long as the inner operand has - the same number of words as what we've seen so far. Then store - the widest mode in MODE. */ - if (subreg_lowpart_p (varop) - && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop))) - > GET_MODE_SIZE (GET_MODE (varop))) - && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) - == mode_words)) - { - varop = SUBREG_REG (varop); - if (GET_MODE_SIZE (GET_MODE (varop)) > GET_MODE_SIZE (mode)) - mode = GET_MODE (varop); - continue; - } - break; - - case MULT: - /* Some machines use MULT instead of ASHIFT because MULT - is cheaper. But it is still better on those machines to - merge two shifts into one. */ - if (GET_CODE (XEXP (varop, 1)) == CONST_INT - && exact_log2 (INTVAL (XEXP (varop, 1))) >= 0) - { - varop = gen_binary (ASHIFT, GET_MODE (varop), XEXP (varop, 0), - GEN_INT (exact_log2 (INTVAL (XEXP (varop, 1)))));; - continue; - } - break; - - case UDIV: - /* Similar, for when divides are cheaper. */ - if (GET_CODE (XEXP (varop, 1)) == CONST_INT - && exact_log2 (INTVAL (XEXP (varop, 1))) >= 0) - { - varop = gen_binary (LSHIFTRT, GET_MODE (varop), XEXP (varop, 0), - GEN_INT (exact_log2 (INTVAL (XEXP (varop, 1))))); - continue; - } - break; - - case ASHIFTRT: - /* If we are extracting just the sign bit of an arithmetic right - shift, that shift is not needed. */ - if (code == LSHIFTRT && count == GET_MODE_BITSIZE (result_mode) - 1) - { - varop = XEXP (varop, 0); - continue; - } - - /* ... fall through ... */ - - case LSHIFTRT: - case ASHIFT: - case ROTATE: - /* Here we have two nested shifts. The result is usually the - AND of a new shift with a mask. We compute the result below. */ - if (GET_CODE (XEXP (varop, 1)) == CONST_INT - && INTVAL (XEXP (varop, 1)) >= 0 - && INTVAL (XEXP (varop, 1)) < GET_MODE_BITSIZE (GET_MODE (varop)) - && GET_MODE_BITSIZE (result_mode) <= HOST_BITS_PER_WIDE_INT - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) - { - enum rtx_code first_code = GET_CODE (varop); - int first_count = INTVAL (XEXP (varop, 1)); - unsigned HOST_WIDE_INT mask; - rtx mask_rtx; - - /* We have one common special case. We can't do any merging if - the inner code is an ASHIFTRT of a smaller mode. However, if - we have (ashift:M1 (subreg:M1 (ashiftrt:M2 FOO C1) 0) C2) - with C2 == GET_MODE_BITSIZE (M1) - GET_MODE_BITSIZE (M2), - we can convert it to - (ashiftrt:M1 (ashift:M1 (and:M1 (subreg:M1 FOO 0 C2) C3) C1). - This simplifies certain SIGN_EXTEND operations. */ - if (code == ASHIFT && first_code == ASHIFTRT - && (GET_MODE_BITSIZE (result_mode) - - GET_MODE_BITSIZE (GET_MODE (varop))) == count) - { - /* C3 has the low-order C1 bits zero. */ - - mask = (GET_MODE_MASK (mode) - & ~ (((HOST_WIDE_INT) 1 << first_count) - 1)); - - varop = simplify_and_const_int (NULL_RTX, result_mode, - XEXP (varop, 0), mask); - varop = simplify_shift_const (NULL_RTX, ASHIFT, result_mode, - varop, count); - count = first_count; - code = ASHIFTRT; - continue; - } - - /* If this was (ashiftrt (ashift foo C1) C2) and FOO has more - than C1 high-order bits equal to the sign bit, we can convert - this to either an ASHIFT or a ASHIFTRT depending on the - two counts. - - We cannot do this if VAROP's mode is not SHIFT_MODE. */ - - if (code == ASHIFTRT && first_code == ASHIFT - && GET_MODE (varop) == shift_mode - && (num_sign_bit_copies (XEXP (varop, 0), shift_mode) - > first_count)) - { - count -= first_count; - if (count < 0) - count = - count, code = ASHIFT; - varop = XEXP (varop, 0); - continue; - } - - /* There are some cases we can't do. If CODE is ASHIFTRT, - we can only do this if FIRST_CODE is also ASHIFTRT. - - We can't do the case when CODE is ROTATE and FIRST_CODE is - ASHIFTRT. - - If the mode of this shift is not the mode of the outer shift, - we can't do this if either shift is a right shift or ROTATE. - - Finally, we can't do any of these if the mode is too wide - unless the codes are the same. - - Handle the case where the shift codes are the same - first. */ - - if (code == first_code) - { - if (GET_MODE (varop) != result_mode - && (code == ASHIFTRT || code == LSHIFTRT - || code == ROTATE)) - break; - - count += first_count; - varop = XEXP (varop, 0); - continue; - } - - if (code == ASHIFTRT - || (code == ROTATE && first_code == ASHIFTRT) - || GET_MODE_BITSIZE (mode) > HOST_BITS_PER_WIDE_INT - || (GET_MODE (varop) != result_mode - && (first_code == ASHIFTRT || first_code == LSHIFTRT - || first_code == ROTATE - || code == ROTATE))) - break; - - /* To compute the mask to apply after the shift, shift the - nonzero bits of the inner shift the same way the - outer shift will. */ - - mask_rtx = GEN_INT (nonzero_bits (varop, GET_MODE (varop))); - - mask_rtx - = simplify_binary_operation (code, result_mode, mask_rtx, - GEN_INT (count)); - - /* Give up if we can't compute an outer operation to use. */ - if (mask_rtx == 0 - || GET_CODE (mask_rtx) != CONST_INT - || ! merge_outer_ops (&outer_op, &outer_const, AND, - INTVAL (mask_rtx), - result_mode, &complement_p)) - break; - - /* If the shifts are in the same direction, we add the - counts. Otherwise, we subtract them. */ - if ((code == ASHIFTRT || code == LSHIFTRT) - == (first_code == ASHIFTRT || first_code == LSHIFTRT)) - count += first_count; - else - count -= first_count; - - /* If COUNT is positive, the new shift is usually CODE, - except for the two exceptions below, in which case it is - FIRST_CODE. If the count is negative, FIRST_CODE should - always be used */ - if (count > 0 - && ((first_code == ROTATE && code == ASHIFT) - || (first_code == ASHIFTRT && code == LSHIFTRT))) - code = first_code; - else if (count < 0) - code = first_code, count = - count; - - varop = XEXP (varop, 0); - continue; - } - - /* If we have (A << B << C) for any shift, we can convert this to - (A << C << B). This wins if A is a constant. Only try this if - B is not a constant. */ - - else if (GET_CODE (varop) == code - && GET_CODE (XEXP (varop, 1)) != CONST_INT - && 0 != (new - = simplify_binary_operation (code, mode, - XEXP (varop, 0), - GEN_INT (count)))) - { - varop = gen_rtx_combine (code, mode, new, XEXP (varop, 1)); - count = 0; - continue; - } - break; - - case NOT: - /* Make this fit the case below. */ - varop = gen_rtx_combine (XOR, mode, XEXP (varop, 0), - GEN_INT (GET_MODE_MASK (mode))); - continue; - - case IOR: - case AND: - case XOR: - /* If we have (xshiftrt (ior (plus X (const_int -1)) X) C) - with C the size of VAROP - 1 and the shift is logical if - STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1, - we have an (le X 0) operation. If we have an arithmetic shift - and STORE_FLAG_VALUE is 1 or we have a logical shift with - STORE_FLAG_VALUE of -1, we have a (neg (le X 0)) operation. */ - - if (GET_CODE (varop) == IOR && GET_CODE (XEXP (varop, 0)) == PLUS - && XEXP (XEXP (varop, 0), 1) == constm1_rtx - && (STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1) - && (code == LSHIFTRT || code == ASHIFTRT) - && count == GET_MODE_BITSIZE (GET_MODE (varop)) - 1 - && rtx_equal_p (XEXP (XEXP (varop, 0), 0), XEXP (varop, 1))) - { - count = 0; - varop = gen_rtx_combine (LE, GET_MODE (varop), XEXP (varop, 1), - const0_rtx); - - if (STORE_FLAG_VALUE == 1 ? code == ASHIFTRT : code == LSHIFTRT) - varop = gen_rtx_combine (NEG, GET_MODE (varop), varop); - - continue; - } - - /* If we have (shift (logical)), move the logical to the outside - to allow it to possibly combine with another logical and the - shift to combine with another shift. This also canonicalizes to - what a ZERO_EXTRACT looks like. Also, some machines have - (and (shift)) insns. */ - - if (GET_CODE (XEXP (varop, 1)) == CONST_INT - && (new = simplify_binary_operation (code, result_mode, - XEXP (varop, 1), - GEN_INT (count))) != 0 - && GET_CODE(new) == CONST_INT - && merge_outer_ops (&outer_op, &outer_const, GET_CODE (varop), - INTVAL (new), result_mode, &complement_p)) - { - varop = XEXP (varop, 0); - continue; - } - - /* If we can't do that, try to simplify the shift in each arm of the - logical expression, make a new logical expression, and apply - the inverse distributive law. */ - { - rtx lhs = simplify_shift_const (NULL_RTX, code, shift_mode, - XEXP (varop, 0), count); - rtx rhs = simplify_shift_const (NULL_RTX, code, shift_mode, - XEXP (varop, 1), count); - - varop = gen_binary (GET_CODE (varop), shift_mode, lhs, rhs); - varop = apply_distributive_law (varop); - - count = 0; - } - break; - - case EQ: - /* convert (lshiftrt (eq FOO 0) C) to (xor FOO 1) if STORE_FLAG_VALUE - says that the sign bit can be tested, FOO has mode MODE, C is - GET_MODE_BITSIZE (MODE) - 1, and FOO has only its low-order bit - that may be nonzero. */ - if (code == LSHIFTRT - && XEXP (varop, 1) == const0_rtx - && GET_MODE (XEXP (varop, 0)) == result_mode - && count == GET_MODE_BITSIZE (result_mode) - 1 - && GET_MODE_BITSIZE (result_mode) <= HOST_BITS_PER_WIDE_INT - && ((STORE_FLAG_VALUE - & ((HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (result_mode) - 1)))) - && nonzero_bits (XEXP (varop, 0), result_mode) == 1 - && merge_outer_ops (&outer_op, &outer_const, XOR, - (HOST_WIDE_INT) 1, result_mode, - &complement_p)) - { - varop = XEXP (varop, 0); - count = 0; - continue; - } - break; - - case NEG: - /* (lshiftrt (neg A) C) where A is either 0 or 1 and C is one less - than the number of bits in the mode is equivalent to A. */ - if (code == LSHIFTRT && count == GET_MODE_BITSIZE (result_mode) - 1 - && nonzero_bits (XEXP (varop, 0), result_mode) == 1) - { - varop = XEXP (varop, 0); - count = 0; - continue; - } - - /* NEG commutes with ASHIFT since it is multiplication. Move the - NEG outside to allow shifts to combine. */ - if (code == ASHIFT - && merge_outer_ops (&outer_op, &outer_const, NEG, - (HOST_WIDE_INT) 0, result_mode, - &complement_p)) - { - varop = XEXP (varop, 0); - continue; - } - break; - - case PLUS: - /* (lshiftrt (plus A -1) C) where A is either 0 or 1 and C - is one less than the number of bits in the mode is - equivalent to (xor A 1). */ - if (code == LSHIFTRT && count == GET_MODE_BITSIZE (result_mode) - 1 - && XEXP (varop, 1) == constm1_rtx - && nonzero_bits (XEXP (varop, 0), result_mode) == 1 - && merge_outer_ops (&outer_op, &outer_const, XOR, - (HOST_WIDE_INT) 1, result_mode, - &complement_p)) - { - count = 0; - varop = XEXP (varop, 0); - continue; - } - - /* If we have (xshiftrt (plus FOO BAR) C), and the only bits - that might be nonzero in BAR are those being shifted out and those - bits are known zero in FOO, we can replace the PLUS with FOO. - Similarly in the other operand order. This code occurs when - we are computing the size of a variable-size array. */ - - if ((code == ASHIFTRT || code == LSHIFTRT) - && count < HOST_BITS_PER_WIDE_INT - && nonzero_bits (XEXP (varop, 1), result_mode) >> count == 0 - && (nonzero_bits (XEXP (varop, 1), result_mode) - & nonzero_bits (XEXP (varop, 0), result_mode)) == 0) - { - varop = XEXP (varop, 0); - continue; - } - else if ((code == ASHIFTRT || code == LSHIFTRT) - && count < HOST_BITS_PER_WIDE_INT - && GET_MODE_BITSIZE (result_mode) <= HOST_BITS_PER_WIDE_INT - && 0 == (nonzero_bits (XEXP (varop, 0), result_mode) - >> count) - && 0 == (nonzero_bits (XEXP (varop, 0), result_mode) - & nonzero_bits (XEXP (varop, 1), - result_mode))) - { - varop = XEXP (varop, 1); - continue; - } - - /* (ashift (plus foo C) N) is (plus (ashift foo N) C'). */ - if (code == ASHIFT - && GET_CODE (XEXP (varop, 1)) == CONST_INT - && (new = simplify_binary_operation (ASHIFT, result_mode, - XEXP (varop, 1), - GEN_INT (count))) != 0 - && GET_CODE(new) == CONST_INT - && merge_outer_ops (&outer_op, &outer_const, PLUS, - INTVAL (new), result_mode, &complement_p)) - { - varop = XEXP (varop, 0); - continue; - } - break; - - case MINUS: - /* If we have (xshiftrt (minus (ashiftrt X C)) X) C) - with C the size of VAROP - 1 and the shift is logical if - STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1, - we have a (gt X 0) operation. If the shift is arithmetic with - STORE_FLAG_VALUE of 1 or logical with STORE_FLAG_VALUE == -1, - we have a (neg (gt X 0)) operation. */ - - if ((STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1) - && GET_CODE (XEXP (varop, 0)) == ASHIFTRT - && count == GET_MODE_BITSIZE (GET_MODE (varop)) - 1 - && (code == LSHIFTRT || code == ASHIFTRT) - && GET_CODE (XEXP (XEXP (varop, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (varop, 0), 1)) == count - && rtx_equal_p (XEXP (XEXP (varop, 0), 0), XEXP (varop, 1))) - { - count = 0; - varop = gen_rtx_combine (GT, GET_MODE (varop), XEXP (varop, 1), - const0_rtx); - - if (STORE_FLAG_VALUE == 1 ? code == ASHIFTRT : code == LSHIFTRT) - varop = gen_rtx_combine (NEG, GET_MODE (varop), varop); - - continue; - } - break; - - case TRUNCATE: - /* Change (lshiftrt (truncate (lshiftrt))) to (truncate (lshiftrt)) - if the truncate does not affect the value. */ - if (code == LSHIFTRT - && GET_CODE (XEXP (varop, 0)) == LSHIFTRT - && GET_CODE (XEXP (XEXP (varop, 0), 1)) == CONST_INT - && (INTVAL (XEXP (XEXP (varop, 0), 1)) - >= (GET_MODE_BITSIZE (GET_MODE (XEXP (varop, 0))) - - GET_MODE_BITSIZE (GET_MODE (varop))))) - { - rtx varop_inner = XEXP (varop, 0); - - varop_inner = gen_rtx_combine (LSHIFTRT, - GET_MODE (varop_inner), - XEXP (varop_inner, 0), - GEN_INT (count + INTVAL (XEXP (varop_inner, 1)))); - varop = gen_rtx_combine (TRUNCATE, GET_MODE (varop), - varop_inner); - count = 0; - continue; - } - break; - - default: - break; - } - - break; - } - - /* We need to determine what mode to do the shift in. If the shift is - a right shift or ROTATE, we must always do it in the mode it was - originally done in. Otherwise, we can do it in MODE, the widest mode - encountered. The code we care about is that of the shift that will - actually be done, not the shift that was originally requested. */ - shift_mode - = (code == ASHIFTRT || code == LSHIFTRT || code == ROTATE - ? result_mode : mode); - - /* We have now finished analyzing the shift. The result should be - a shift of type CODE with SHIFT_MODE shifting VAROP COUNT places. If - OUTER_OP is non-NIL, it is an operation that needs to be applied - to the result of the shift. OUTER_CONST is the relevant constant, - but we must turn off all bits turned off in the shift. - - If we were passed a value for X, see if we can use any pieces of - it. If not, make new rtx. */ - - if (x && GET_RTX_CLASS (GET_CODE (x)) == '2' - && GET_CODE (XEXP (x, 1)) == CONST_INT - && INTVAL (XEXP (x, 1)) == count) - const_rtx = XEXP (x, 1); - else - const_rtx = GEN_INT (count); - - if (x && GET_CODE (XEXP (x, 0)) == SUBREG - && GET_MODE (XEXP (x, 0)) == shift_mode - && SUBREG_REG (XEXP (x, 0)) == varop) - varop = XEXP (x, 0); - else if (GET_MODE (varop) != shift_mode) - varop = gen_lowpart_for_combine (shift_mode, varop); - - /* If we can't make the SUBREG, try to return what we were given. */ - if (GET_CODE (varop) == CLOBBER) - return x ? x : varop; - - new = simplify_binary_operation (code, shift_mode, varop, const_rtx); - if (new != 0) - x = new; - else - { - if (x == 0 || GET_CODE (x) != code || GET_MODE (x) != shift_mode) - x = gen_rtx_combine (code, shift_mode, varop, const_rtx); - - SUBST (XEXP (x, 0), varop); - SUBST (XEXP (x, 1), const_rtx); - } - - /* If we have an outer operation and we just made a shift, it is - possible that we could have simplified the shift were it not - for the outer operation. So try to do the simplification - recursively. */ - - if (outer_op != NIL && GET_CODE (x) == code - && GET_CODE (XEXP (x, 1)) == CONST_INT) - x = simplify_shift_const (x, code, shift_mode, XEXP (x, 0), - INTVAL (XEXP (x, 1))); - - /* If we were doing a LSHIFTRT in a wider mode than it was originally, - turn off all the bits that the shift would have turned off. */ - if (orig_code == LSHIFTRT && result_mode != shift_mode) - x = simplify_and_const_int (NULL_RTX, shift_mode, x, - GET_MODE_MASK (result_mode) >> orig_count); - - /* Do the remainder of the processing in RESULT_MODE. */ - x = gen_lowpart_for_combine (result_mode, x); - - /* If COMPLEMENT_P is set, we have to complement X before doing the outer - operation. */ - if (complement_p) - x = gen_unary (NOT, result_mode, result_mode, x); - - if (outer_op != NIL) - { - if (GET_MODE_BITSIZE (result_mode) < HOST_BITS_PER_WIDE_INT) - { - int width = GET_MODE_BITSIZE (result_mode); - - outer_const &= GET_MODE_MASK (result_mode); - - /* If this would be an entire word for the target, but is not for - the host, then sign-extend on the host so that the number will - look the same way on the host that it would on the target. - - For example, when building a 64 bit alpha hosted 32 bit sparc - targeted compiler, then we want the 32 bit unsigned value -1 to be - represented as a 64 bit value -1, and not as 0x00000000ffffffff. - The later confuses the sparc backend. */ - - if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width - && (outer_const & ((HOST_WIDE_INT) 1 << (width - 1)))) - outer_const |= ((HOST_WIDE_INT) (-1) << width); - } - - if (outer_op == AND) - x = simplify_and_const_int (NULL_RTX, result_mode, x, outer_const); - else if (outer_op == SET) - /* This means that we have determined that the result is - equivalent to a constant. This should be rare. */ - x = GEN_INT (outer_const); - else if (GET_RTX_CLASS (outer_op) == '1') - x = gen_unary (outer_op, result_mode, result_mode, x); - else - x = gen_binary (outer_op, result_mode, x, GEN_INT (outer_const)); - } - - return x; -} - -/* Like recog, but we receive the address of a pointer to a new pattern. - We try to match the rtx that the pointer points to. - If that fails, we may try to modify or replace the pattern, - storing the replacement into the same pointer object. - - Modifications include deletion or addition of CLOBBERs. - - PNOTES is a pointer to a location where any REG_UNUSED notes added for - the CLOBBERs are placed. - - The value is the final insn code from the pattern ultimately matched, - or -1. */ - -static int -recog_for_combine (pnewpat, insn, pnotes) - rtx *pnewpat; - rtx insn; - rtx *pnotes; -{ - register rtx pat = *pnewpat; - int insn_code_number; - int num_clobbers_to_add = 0; - int i; - rtx notes = 0; - - /* If PAT is a PARALLEL, check to see if it contains the CLOBBER - we use to indicate that something didn't match. If we find such a - thing, force rejection. */ - if (GET_CODE (pat) == PARALLEL) - for (i = XVECLEN (pat, 0) - 1; i >= 0; i--) - if (GET_CODE (XVECEXP (pat, 0, i)) == CLOBBER - && XEXP (XVECEXP (pat, 0, i), 0) == const0_rtx) - return -1; - - /* Is the result of combination a valid instruction? */ - insn_code_number = recog (pat, insn, &num_clobbers_to_add); - - /* If it isn't, there is the possibility that we previously had an insn - that clobbered some register as a side effect, but the combined - insn doesn't need to do that. So try once more without the clobbers - unless this represents an ASM insn. */ - - if (insn_code_number < 0 && ! check_asm_operands (pat) - && GET_CODE (pat) == PARALLEL) - { - int pos; - - for (pos = 0, i = 0; i < XVECLEN (pat, 0); i++) - if (GET_CODE (XVECEXP (pat, 0, i)) != CLOBBER) - { - if (i != pos) - SUBST (XVECEXP (pat, 0, pos), XVECEXP (pat, 0, i)); - pos++; - } - - SUBST_INT (XVECLEN (pat, 0), pos); - - if (pos == 1) - pat = XVECEXP (pat, 0, 0); - - insn_code_number = recog (pat, insn, &num_clobbers_to_add); - } - - /* If we had any clobbers to add, make a new pattern than contains - them. Then check to make sure that all of them are dead. */ - if (num_clobbers_to_add) - { - rtx newpat = gen_rtx_PARALLEL (VOIDmode, - gen_rtvec (GET_CODE (pat) == PARALLEL - ? XVECLEN (pat, 0) + num_clobbers_to_add - : num_clobbers_to_add + 1)); - - if (GET_CODE (pat) == PARALLEL) - for (i = 0; i < XVECLEN (pat, 0); i++) - XVECEXP (newpat, 0, i) = XVECEXP (pat, 0, i); - else - XVECEXP (newpat, 0, 0) = pat; - - add_clobbers (newpat, insn_code_number); - - for (i = XVECLEN (newpat, 0) - num_clobbers_to_add; - i < XVECLEN (newpat, 0); i++) - { - if (GET_CODE (XEXP (XVECEXP (newpat, 0, i), 0)) == REG - && ! reg_dead_at_p (XEXP (XVECEXP (newpat, 0, i), 0), insn)) - return -1; - notes = gen_rtx_EXPR_LIST (REG_UNUSED, - XEXP (XVECEXP (newpat, 0, i), 0), notes); - } - pat = newpat; - } - - *pnewpat = pat; - *pnotes = notes; - - return insn_code_number; -} - -/* Like gen_lowpart but for use by combine. In combine it is not possible - to create any new pseudoregs. However, it is safe to create - invalid memory addresses, because combine will try to recognize - them and all they will do is make the combine attempt fail. - - If for some reason this cannot do its job, an rtx - (clobber (const_int 0)) is returned. - An insn containing that will not be recognized. */ - -#undef gen_lowpart - -static rtx -gen_lowpart_for_combine (mode, x) - enum machine_mode mode; - register rtx x; -{ - rtx result; - - if (GET_MODE (x) == mode) - return x; - - /* We can only support MODE being wider than a word if X is a - constant integer or has a mode the same size. */ - - if (GET_MODE_SIZE (mode) > UNITS_PER_WORD - && ! ((GET_MODE (x) == VOIDmode - && (GET_CODE (x) == CONST_INT - || GET_CODE (x) == CONST_DOUBLE)) - || GET_MODE_SIZE (GET_MODE (x)) == GET_MODE_SIZE (mode))) - return gen_rtx_CLOBBER (GET_MODE (x), const0_rtx); - - /* X might be a paradoxical (subreg (mem)). In that case, gen_lowpart - won't know what to do. So we will strip off the SUBREG here and - process normally. */ - if (GET_CODE (x) == SUBREG && GET_CODE (SUBREG_REG (x)) == MEM) - { - x = SUBREG_REG (x); - if (GET_MODE (x) == mode) - return x; - } - - result = gen_lowpart_common (mode, x); - if (result != 0 - && GET_CODE (result) == SUBREG - && GET_CODE (SUBREG_REG (result)) == REG - && REGNO (SUBREG_REG (result)) >= FIRST_PSEUDO_REGISTER - && (GET_MODE_SIZE (GET_MODE (result)) - != GET_MODE_SIZE (GET_MODE (SUBREG_REG (result))))) - REG_CHANGES_SIZE (REGNO (SUBREG_REG (result))) = 1; - - if (result) - return result; - - if (GET_CODE (x) == MEM) - { - register int offset = 0; - rtx new; - - /* Refuse to work on a volatile memory ref or one with a mode-dependent - address. */ - if (MEM_VOLATILE_P (x) || mode_dependent_address_p (XEXP (x, 0))) - return gen_rtx_CLOBBER (GET_MODE (x), const0_rtx); - - /* If we want to refer to something bigger than the original memref, - generate a perverse subreg instead. That will force a reload - of the original memref X. */ - if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (mode)) - return gen_rtx_SUBREG (mode, x, 0); - - if (WORDS_BIG_ENDIAN) - offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD) - - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD)); - if (BYTES_BIG_ENDIAN) - { - /* Adjust the address so that the address-after-the-data is - unchanged. */ - offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode)) - - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x)))); - } - new = gen_rtx_MEM (mode, plus_constant (XEXP (x, 0), offset)); - RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (x); - MEM_COPY_ATTRIBUTES (new, x); - return new; - } - - /* If X is a comparison operator, rewrite it in a new mode. This - probably won't match, but may allow further simplifications. */ - else if (GET_RTX_CLASS (GET_CODE (x)) == '<') - return gen_rtx_combine (GET_CODE (x), mode, XEXP (x, 0), XEXP (x, 1)); - - /* If we couldn't simplify X any other way, just enclose it in a - SUBREG. Normally, this SUBREG won't match, but some patterns may - include an explicit SUBREG or we may simplify it further in combine. */ - else - { - int word = 0; - - if (WORDS_BIG_ENDIAN && GET_MODE_SIZE (GET_MODE (x)) > UNITS_PER_WORD) - word = ((GET_MODE_SIZE (GET_MODE (x)) - - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD)) - / UNITS_PER_WORD); - return gen_rtx_SUBREG (mode, x, word); - } -} - -/* Make an rtx expression. This is a subset of gen_rtx and only supports - expressions of 1, 2, or 3 operands, each of which are rtx expressions. - - If the identical expression was previously in the insn (in the undobuf), - it will be returned. Only if it is not found will a new expression - be made. */ - -/*VARARGS2*/ -static rtx -gen_rtx_combine VPROTO((enum rtx_code code, enum machine_mode mode, ...)) -{ -#ifndef ANSI_PROTOTYPES - enum rtx_code code; - enum machine_mode mode; -#endif - va_list p; - int n_args; - rtx args[3]; - int j; - char *fmt; - rtx rt; - struct undo *undo; - - VA_START (p, mode); - -#ifndef ANSI_PROTOTYPES - code = va_arg (p, enum rtx_code); - mode = va_arg (p, enum machine_mode); -#endif - - n_args = GET_RTX_LENGTH (code); - fmt = GET_RTX_FORMAT (code); - - if (n_args == 0 || n_args > 3) - abort (); - - /* Get each arg and verify that it is supposed to be an expression. */ - for (j = 0; j < n_args; j++) - { - if (*fmt++ != 'e') - abort (); - - args[j] = va_arg (p, rtx); - } - - /* See if this is in undobuf. Be sure we don't use objects that came - from another insn; this could produce circular rtl structures. */ - - for (undo = undobuf.undos; undo != undobuf.previous_undos; undo = undo->next) - if (!undo->is_int - && GET_CODE (undo->old_contents.r) == code - && GET_MODE (undo->old_contents.r) == mode) - { - for (j = 0; j < n_args; j++) - if (XEXP (undo->old_contents.r, j) != args[j]) - break; - - if (j == n_args) - return undo->old_contents.r; - } - - /* Otherwise make a new rtx. We know we have 1, 2, or 3 args. - Use rtx_alloc instead of gen_rtx because it's faster on RISC. */ - rt = rtx_alloc (code); - PUT_MODE (rt, mode); - XEXP (rt, 0) = args[0]; - if (n_args > 1) - { - XEXP (rt, 1) = args[1]; - if (n_args > 2) - XEXP (rt, 2) = args[2]; - } - return rt; -} - -/* These routines make binary and unary operations by first seeing if they - fold; if not, a new expression is allocated. */ - -static rtx -gen_binary (code, mode, op0, op1) - enum rtx_code code; - enum machine_mode mode; - rtx op0, op1; -{ - rtx result; - rtx tem; - - if (GET_RTX_CLASS (code) == 'c' - && (GET_CODE (op0) == CONST_INT - || (CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT))) - tem = op0, op0 = op1, op1 = tem; - - if (GET_RTX_CLASS (code) == '<') - { - enum machine_mode op_mode = GET_MODE (op0); - - /* Strip the COMPARE from (REL_OP (compare X Y) 0) to get - just (REL_OP X Y). */ - if (GET_CODE (op0) == COMPARE && op1 == const0_rtx) - { - op1 = XEXP (op0, 1); - op0 = XEXP (op0, 0); - op_mode = GET_MODE (op0); - } - - if (op_mode == VOIDmode) - op_mode = GET_MODE (op1); - result = simplify_relational_operation (code, op_mode, op0, op1); - } - else - result = simplify_binary_operation (code, mode, op0, op1); - - if (result) - return result; - - /* Put complex operands first and constants second. */ - if (GET_RTX_CLASS (code) == 'c' - && ((CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT) - || (GET_RTX_CLASS (GET_CODE (op0)) == 'o' - && GET_RTX_CLASS (GET_CODE (op1)) != 'o') - || (GET_CODE (op0) == SUBREG - && GET_RTX_CLASS (GET_CODE (SUBREG_REG (op0))) == 'o' - && GET_RTX_CLASS (GET_CODE (op1)) != 'o'))) - return gen_rtx_combine (code, mode, op1, op0); - - /* If we are turning off bits already known off in OP0, we need not do - an AND. */ - else if (code == AND && GET_CODE (op1) == CONST_INT - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (op0, mode) & ~ INTVAL (op1)) == 0) - return op0; - - return gen_rtx_combine (code, mode, op0, op1); -} - -static rtx -gen_unary (code, mode, op0_mode, op0) - enum rtx_code code; - enum machine_mode mode, op0_mode; - rtx op0; -{ - rtx result = simplify_unary_operation (code, mode, op0, op0_mode); - - if (result) - return result; - - return gen_rtx_combine (code, mode, op0); -} - -/* Simplify a comparison between *POP0 and *POP1 where CODE is the - comparison code that will be tested. - - The result is a possibly different comparison code to use. *POP0 and - *POP1 may be updated. - - It is possible that we might detect that a comparison is either always - true or always false. However, we do not perform general constant - folding in combine, so this knowledge isn't useful. Such tautologies - should have been detected earlier. Hence we ignore all such cases. */ - -static enum rtx_code -simplify_comparison (code, pop0, pop1) - enum rtx_code code; - rtx *pop0; - rtx *pop1; -{ - rtx op0 = *pop0; - rtx op1 = *pop1; - rtx tem, tem1; - int i; - enum machine_mode mode, tmode; - - /* Try a few ways of applying the same transformation to both operands. */ - while (1) - { -#ifndef WORD_REGISTER_OPERATIONS - /* The test below this one won't handle SIGN_EXTENDs on these machines, - so check specially. */ - if (code != GTU && code != GEU && code != LTU && code != LEU - && GET_CODE (op0) == ASHIFTRT && GET_CODE (op1) == ASHIFTRT - && GET_CODE (XEXP (op0, 0)) == ASHIFT - && GET_CODE (XEXP (op1, 0)) == ASHIFT - && GET_CODE (XEXP (XEXP (op0, 0), 0)) == SUBREG - && GET_CODE (XEXP (XEXP (op1, 0), 0)) == SUBREG - && (GET_MODE (SUBREG_REG (XEXP (XEXP (op0, 0), 0))) - == GET_MODE (SUBREG_REG (XEXP (XEXP (op1, 0), 0)))) - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && GET_CODE (XEXP (op1, 1)) == CONST_INT - && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT - && GET_CODE (XEXP (XEXP (op1, 0), 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) == INTVAL (XEXP (op1, 1)) - && INTVAL (XEXP (op0, 1)) == INTVAL (XEXP (XEXP (op0, 0), 1)) - && INTVAL (XEXP (op0, 1)) == INTVAL (XEXP (XEXP (op1, 0), 1)) - && (INTVAL (XEXP (op0, 1)) - == (GET_MODE_BITSIZE (GET_MODE (op0)) - - (GET_MODE_BITSIZE - (GET_MODE (SUBREG_REG (XEXP (XEXP (op0, 0), 0)))))))) - { - op0 = SUBREG_REG (XEXP (XEXP (op0, 0), 0)); - op1 = SUBREG_REG (XEXP (XEXP (op1, 0), 0)); - } -#endif - - /* If both operands are the same constant shift, see if we can ignore the - shift. We can if the shift is a rotate or if the bits shifted out of - this shift are known to be zero for both inputs and if the type of - comparison is compatible with the shift. */ - if (GET_CODE (op0) == GET_CODE (op1) - && GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT - && ((GET_CODE (op0) == ROTATE && (code == NE || code == EQ)) - || ((GET_CODE (op0) == LSHIFTRT || GET_CODE (op0) == ASHIFT) - && (code != GT && code != LT && code != GE && code != LE)) - || (GET_CODE (op0) == ASHIFTRT - && (code != GTU && code != LTU - && code != GEU && code != GEU))) - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) >= 0 - && INTVAL (XEXP (op0, 1)) < HOST_BITS_PER_WIDE_INT - && XEXP (op0, 1) == XEXP (op1, 1)) - { - enum machine_mode mode = GET_MODE (op0); - unsigned HOST_WIDE_INT mask = GET_MODE_MASK (mode); - int shift_count = INTVAL (XEXP (op0, 1)); - - if (GET_CODE (op0) == LSHIFTRT || GET_CODE (op0) == ASHIFTRT) - mask &= (mask >> shift_count) << shift_count; - else if (GET_CODE (op0) == ASHIFT) - mask = (mask & (mask << shift_count)) >> shift_count; - - if ((nonzero_bits (XEXP (op0, 0), mode) & ~ mask) == 0 - && (nonzero_bits (XEXP (op1, 0), mode) & ~ mask) == 0) - op0 = XEXP (op0, 0), op1 = XEXP (op1, 0); - else - break; - } - - /* If both operands are AND's of a paradoxical SUBREG by constant, the - SUBREGs are of the same mode, and, in both cases, the AND would - be redundant if the comparison was done in the narrower mode, - do the comparison in the narrower mode (e.g., we are AND'ing with 1 - and the operand's possibly nonzero bits are 0xffffff01; in that case - if we only care about QImode, we don't need the AND). This case - occurs if the output mode of an scc insn is not SImode and - STORE_FLAG_VALUE == 1 (e.g., the 386). - - Similarly, check for a case where the AND's are ZERO_EXTEND - operations from some narrower mode even though a SUBREG is not - present. */ - - else if (GET_CODE (op0) == AND && GET_CODE (op1) == AND - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && GET_CODE (XEXP (op1, 1)) == CONST_INT) - { - rtx inner_op0 = XEXP (op0, 0); - rtx inner_op1 = XEXP (op1, 0); - HOST_WIDE_INT c0 = INTVAL (XEXP (op0, 1)); - HOST_WIDE_INT c1 = INTVAL (XEXP (op1, 1)); - int changed = 0; - - if (GET_CODE (inner_op0) == SUBREG && GET_CODE (inner_op1) == SUBREG - && (GET_MODE_SIZE (GET_MODE (inner_op0)) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (inner_op0)))) - && (GET_MODE (SUBREG_REG (inner_op0)) - == GET_MODE (SUBREG_REG (inner_op1))) - && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (inner_op0))) - <= HOST_BITS_PER_WIDE_INT) - && (0 == ((~c0) & nonzero_bits (SUBREG_REG (inner_op0), - GET_MODE (SUBREG_REG (inner_op0))))) - && (0 == ((~c1) & nonzero_bits (SUBREG_REG (inner_op1), - GET_MODE (SUBREG_REG (inner_op1)))))) - { - op0 = SUBREG_REG (inner_op0); - op1 = SUBREG_REG (inner_op1); - - /* The resulting comparison is always unsigned since we masked - off the original sign bit. */ - code = unsigned_condition (code); - - changed = 1; - } - - else if (c0 == c1) - for (tmode = GET_CLASS_NARROWEST_MODE - (GET_MODE_CLASS (GET_MODE (op0))); - tmode != GET_MODE (op0); tmode = GET_MODE_WIDER_MODE (tmode)) - if ((unsigned HOST_WIDE_INT) c0 == GET_MODE_MASK (tmode)) - { - op0 = gen_lowpart_for_combine (tmode, inner_op0); - op1 = gen_lowpart_for_combine (tmode, inner_op1); - code = unsigned_condition (code); - changed = 1; - break; - } - - if (! changed) - break; - } - - /* If both operands are NOT, we can strip off the outer operation - and adjust the comparison code for swapped operands; similarly for - NEG, except that this must be an equality comparison. */ - else if ((GET_CODE (op0) == NOT && GET_CODE (op1) == NOT) - || (GET_CODE (op0) == NEG && GET_CODE (op1) == NEG - && (code == EQ || code == NE))) - op0 = XEXP (op0, 0), op1 = XEXP (op1, 0), code = swap_condition (code); - - else - break; - } - - /* If the first operand is a constant, swap the operands and adjust the - comparison code appropriately, but don't do this if the second operand - is already a constant integer. */ - if (CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT) - { - tem = op0, op0 = op1, op1 = tem; - code = swap_condition (code); - } - - /* We now enter a loop during which we will try to simplify the comparison. - For the most part, we only are concerned with comparisons with zero, - but some things may really be comparisons with zero but not start - out looking that way. */ - - while (GET_CODE (op1) == CONST_INT) - { - enum machine_mode mode = GET_MODE (op0); - int mode_width = GET_MODE_BITSIZE (mode); - unsigned HOST_WIDE_INT mask = GET_MODE_MASK (mode); - int equality_comparison_p; - int sign_bit_comparison_p; - int unsigned_comparison_p; - HOST_WIDE_INT const_op; - - /* We only want to handle integral modes. This catches VOIDmode, - CCmode, and the floating-point modes. An exception is that we - can handle VOIDmode if OP0 is a COMPARE or a comparison - operation. */ - - if (GET_MODE_CLASS (mode) != MODE_INT - && ! (mode == VOIDmode - && (GET_CODE (op0) == COMPARE - || GET_RTX_CLASS (GET_CODE (op0)) == '<'))) - break; - - /* Get the constant we are comparing against and turn off all bits - not on in our mode. */ - const_op = INTVAL (op1); - if (mode_width <= HOST_BITS_PER_WIDE_INT) - const_op &= mask; - - /* If we are comparing against a constant power of two and the value - being compared can only have that single bit nonzero (e.g., it was - `and'ed with that bit), we can replace this with a comparison - with zero. */ - if (const_op - && (code == EQ || code == NE || code == GE || code == GEU - || code == LT || code == LTU) - && mode_width <= HOST_BITS_PER_WIDE_INT - && exact_log2 (const_op) >= 0 - && nonzero_bits (op0, mode) == (unsigned HOST_WIDE_INT) const_op) - { - code = (code == EQ || code == GE || code == GEU ? NE : EQ); - op1 = const0_rtx, const_op = 0; - } - - /* Similarly, if we are comparing a value known to be either -1 or - 0 with -1, change it to the opposite comparison against zero. */ - - if (const_op == -1 - && (code == EQ || code == NE || code == GT || code == LE - || code == GEU || code == LTU) - && num_sign_bit_copies (op0, mode) == mode_width) - { - code = (code == EQ || code == LE || code == GEU ? NE : EQ); - op1 = const0_rtx, const_op = 0; - } - - /* Do some canonicalizations based on the comparison code. We prefer - comparisons against zero and then prefer equality comparisons. - If we can reduce the size of a constant, we will do that too. */ - - switch (code) - { - case LT: - /* < C is equivalent to <= (C - 1) */ - if (const_op > 0) - { - const_op -= 1; - op1 = GEN_INT (const_op); - code = LE; - /* ... fall through to LE case below. */ - } - else - break; - - case LE: - /* <= C is equivalent to < (C + 1); we do this for C < 0 */ - if (const_op < 0) - { - const_op += 1; - op1 = GEN_INT (const_op); - code = LT; - } - - /* If we are doing a <= 0 comparison on a value known to have - a zero sign bit, we can replace this with == 0. */ - else if (const_op == 0 - && mode_width <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (op0, mode) - & ((HOST_WIDE_INT) 1 << (mode_width - 1))) == 0) - code = EQ; - break; - - case GE: - /* >= C is equivalent to > (C - 1). */ - if (const_op > 0) - { - const_op -= 1; - op1 = GEN_INT (const_op); - code = GT; - /* ... fall through to GT below. */ - } - else - break; - - case GT: - /* > C is equivalent to >= (C + 1); we do this for C < 0*/ - if (const_op < 0) - { - const_op += 1; - op1 = GEN_INT (const_op); - code = GE; - } - - /* If we are doing a > 0 comparison on a value known to have - a zero sign bit, we can replace this with != 0. */ - else if (const_op == 0 - && mode_width <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (op0, mode) - & ((HOST_WIDE_INT) 1 << (mode_width - 1))) == 0) - code = NE; - break; - - case LTU: - /* < C is equivalent to <= (C - 1). */ - if (const_op > 0) - { - const_op -= 1; - op1 = GEN_INT (const_op); - code = LEU; - /* ... fall through ... */ - } - - /* (unsigned) < 0x80000000 is equivalent to >= 0. */ - else if ((mode_width <= HOST_BITS_PER_WIDE_INT) - && (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1))) - { - const_op = 0, op1 = const0_rtx; - code = GE; - break; - } - else - break; - - case LEU: - /* unsigned <= 0 is equivalent to == 0 */ - if (const_op == 0) - code = EQ; - - /* (unsigned) <= 0x7fffffff is equivalent to >= 0. */ - else if ((mode_width <= HOST_BITS_PER_WIDE_INT) - && (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)) - { - const_op = 0, op1 = const0_rtx; - code = GE; - } - break; - - case GEU: - /* >= C is equivalent to < (C - 1). */ - if (const_op > 1) - { - const_op -= 1; - op1 = GEN_INT (const_op); - code = GTU; - /* ... fall through ... */ - } - - /* (unsigned) >= 0x80000000 is equivalent to < 0. */ - else if ((mode_width <= HOST_BITS_PER_WIDE_INT) - && (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1))) - { - const_op = 0, op1 = const0_rtx; - code = LT; - break; - } - else - break; - - case GTU: - /* unsigned > 0 is equivalent to != 0 */ - if (const_op == 0) - code = NE; - - /* (unsigned) > 0x7fffffff is equivalent to < 0. */ - else if ((mode_width <= HOST_BITS_PER_WIDE_INT) - && (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)) - { - const_op = 0, op1 = const0_rtx; - code = LT; - } - break; - - default: - break; - } - - /* Compute some predicates to simplify code below. */ - - equality_comparison_p = (code == EQ || code == NE); - sign_bit_comparison_p = ((code == LT || code == GE) && const_op == 0); - unsigned_comparison_p = (code == LTU || code == LEU || code == GTU - || code == LEU); - - /* If this is a sign bit comparison and we can do arithmetic in - MODE, say that we will only be needing the sign bit of OP0. */ - if (sign_bit_comparison_p - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) - op0 = force_to_mode (op0, mode, - ((HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (mode) - 1)), - NULL_RTX, 0); - - /* Now try cases based on the opcode of OP0. If none of the cases - does a "continue", we exit this loop immediately after the - switch. */ - - switch (GET_CODE (op0)) - { - case ZERO_EXTRACT: - /* If we are extracting a single bit from a variable position in - a constant that has only a single bit set and are comparing it - with zero, we can convert this into an equality comparison - between the position and the location of the single bit. */ - - if (GET_CODE (XEXP (op0, 0)) == CONST_INT - && XEXP (op0, 1) == const1_rtx - && equality_comparison_p && const_op == 0 - && (i = exact_log2 (INTVAL (XEXP (op0, 0)))) >= 0) - { - if (BITS_BIG_ENDIAN) - { -#ifdef HAVE_extzv - mode = insn_operand_mode[(int) CODE_FOR_extzv][1]; - if (mode == VOIDmode) - mode = word_mode; - i = (GET_MODE_BITSIZE (mode) - 1 - i); -#else - i = BITS_PER_WORD - 1 - i; -#endif - } - - op0 = XEXP (op0, 2); - op1 = GEN_INT (i); - const_op = i; - - /* Result is nonzero iff shift count is equal to I. */ - code = reverse_condition (code); - continue; - } - - /* ... fall through ... */ - - case SIGN_EXTRACT: - tem = expand_compound_operation (op0); - if (tem != op0) - { - op0 = tem; - continue; - } - break; - - case NOT: - /* If testing for equality, we can take the NOT of the constant. */ - if (equality_comparison_p - && (tem = simplify_unary_operation (NOT, mode, op1, mode)) != 0) - { - op0 = XEXP (op0, 0); - op1 = tem; - continue; - } - - /* If just looking at the sign bit, reverse the sense of the - comparison. */ - if (sign_bit_comparison_p) - { - op0 = XEXP (op0, 0); - code = (code == GE ? LT : GE); - continue; - } - break; - - case NEG: - /* If testing for equality, we can take the NEG of the constant. */ - if (equality_comparison_p - && (tem = simplify_unary_operation (NEG, mode, op1, mode)) != 0) - { - op0 = XEXP (op0, 0); - op1 = tem; - continue; - } - - /* The remaining cases only apply to comparisons with zero. */ - if (const_op != 0) - break; - - /* When X is ABS or is known positive, - (neg X) is < 0 if and only if X != 0. */ - - if (sign_bit_comparison_p - && (GET_CODE (XEXP (op0, 0)) == ABS - || (mode_width <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (XEXP (op0, 0), mode) - & ((HOST_WIDE_INT) 1 << (mode_width - 1))) == 0))) - { - op0 = XEXP (op0, 0); - code = (code == LT ? NE : EQ); - continue; - } - - /* If we have NEG of something whose two high-order bits are the - same, we know that "(-a) < 0" is equivalent to "a > 0". */ - if (num_sign_bit_copies (op0, mode) >= 2) - { - op0 = XEXP (op0, 0); - code = swap_condition (code); - continue; - } - break; - - case ROTATE: - /* If we are testing equality and our count is a constant, we - can perform the inverse operation on our RHS. */ - if (equality_comparison_p && GET_CODE (XEXP (op0, 1)) == CONST_INT - && (tem = simplify_binary_operation (ROTATERT, mode, - op1, XEXP (op0, 1))) != 0) - { - op0 = XEXP (op0, 0); - op1 = tem; - continue; - } - - /* If we are doing a < 0 or >= 0 comparison, it means we are testing - a particular bit. Convert it to an AND of a constant of that - bit. This will be converted into a ZERO_EXTRACT. */ - if (const_op == 0 && sign_bit_comparison_p - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && mode_width <= HOST_BITS_PER_WIDE_INT) - { - op0 = simplify_and_const_int (NULL_RTX, mode, XEXP (op0, 0), - ((HOST_WIDE_INT) 1 - << (mode_width - 1 - - INTVAL (XEXP (op0, 1))))); - code = (code == LT ? NE : EQ); - continue; - } - - /* ... fall through ... */ - - case ABS: - /* ABS is ignorable inside an equality comparison with zero. */ - if (const_op == 0 && equality_comparison_p) - { - op0 = XEXP (op0, 0); - continue; - } - break; - - - case SIGN_EXTEND: - /* Can simplify (compare (zero/sign_extend FOO) CONST) - to (compare FOO CONST) if CONST fits in FOO's mode and we - are either testing inequality or have an unsigned comparison - with ZERO_EXTEND or a signed comparison with SIGN_EXTEND. */ - if (! unsigned_comparison_p - && (GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0))) - <= HOST_BITS_PER_WIDE_INT) - && ((unsigned HOST_WIDE_INT) const_op - < (((unsigned HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0))) - 1))))) - { - op0 = XEXP (op0, 0); - continue; - } - break; - - case SUBREG: - /* Check for the case where we are comparing A - C1 with C2, - both constants are smaller than 1/2 the maximum positive - value in MODE, and the comparison is equality or unsigned. - In that case, if A is either zero-extended to MODE or has - sufficient sign bits so that the high-order bit in MODE - is a copy of the sign in the inner mode, we can prove that it is - safe to do the operation in the wider mode. This simplifies - many range checks. */ - - if (mode_width <= HOST_BITS_PER_WIDE_INT - && subreg_lowpart_p (op0) - && GET_CODE (SUBREG_REG (op0)) == PLUS - && GET_CODE (XEXP (SUBREG_REG (op0), 1)) == CONST_INT - && INTVAL (XEXP (SUBREG_REG (op0), 1)) < 0 - && (- INTVAL (XEXP (SUBREG_REG (op0), 1)) - < (HOST_WIDE_INT)(GET_MODE_MASK (mode) / 2)) - && (unsigned HOST_WIDE_INT) const_op < GET_MODE_MASK (mode) / 2 - && (0 == (nonzero_bits (XEXP (SUBREG_REG (op0), 0), - GET_MODE (SUBREG_REG (op0))) - & ~ GET_MODE_MASK (mode)) - || (num_sign_bit_copies (XEXP (SUBREG_REG (op0), 0), - GET_MODE (SUBREG_REG (op0))) - > (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0))) - - GET_MODE_BITSIZE (mode))))) - { - op0 = SUBREG_REG (op0); - continue; - } - - /* If the inner mode is narrower and we are extracting the low part, - we can treat the SUBREG as if it were a ZERO_EXTEND. */ - if (subreg_lowpart_p (op0) - && GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0))) < mode_width) - /* Fall through */ ; - else - break; - - /* ... fall through ... */ - - case ZERO_EXTEND: - if ((unsigned_comparison_p || equality_comparison_p) - && (GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0))) - <= HOST_BITS_PER_WIDE_INT) - && ((unsigned HOST_WIDE_INT) const_op - < GET_MODE_MASK (GET_MODE (XEXP (op0, 0))))) - { - op0 = XEXP (op0, 0); - continue; - } - break; - - case PLUS: - /* (eq (plus X A) B) -> (eq X (minus B A)). We can only do - this for equality comparisons due to pathological cases involving - overflows. */ - if (equality_comparison_p - && 0 != (tem = simplify_binary_operation (MINUS, mode, - op1, XEXP (op0, 1)))) - { - op0 = XEXP (op0, 0); - op1 = tem; - continue; - } - - /* (plus (abs X) (const_int -1)) is < 0 if and only if X == 0. */ - if (const_op == 0 && XEXP (op0, 1) == constm1_rtx - && GET_CODE (XEXP (op0, 0)) == ABS && sign_bit_comparison_p) - { - op0 = XEXP (XEXP (op0, 0), 0); - code = (code == LT ? EQ : NE); - continue; - } - break; - - case MINUS: - /* (eq (minus A B) C) -> (eq A (plus B C)) or - (eq B (minus A C)), whichever simplifies. We can only do - this for equality comparisons due to pathological cases involving - overflows. */ - if (equality_comparison_p - && 0 != (tem = simplify_binary_operation (PLUS, mode, - XEXP (op0, 1), op1))) - { - op0 = XEXP (op0, 0); - op1 = tem; - continue; - } - - if (equality_comparison_p - && 0 != (tem = simplify_binary_operation (MINUS, mode, - XEXP (op0, 0), op1))) - { - op0 = XEXP (op0, 1); - op1 = tem; - continue; - } - - /* The sign bit of (minus (ashiftrt X C) X), where C is the number - of bits in X minus 1, is one iff X > 0. */ - if (sign_bit_comparison_p && GET_CODE (XEXP (op0, 0)) == ASHIFTRT - && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (op0, 0), 1)) == mode_width - 1 - && rtx_equal_p (XEXP (XEXP (op0, 0), 0), XEXP (op0, 1))) - { - op0 = XEXP (op0, 1); - code = (code == GE ? LE : GT); - continue; - } - break; - - case XOR: - /* (eq (xor A B) C) -> (eq A (xor B C)). This is a simplification - if C is zero or B is a constant. */ - if (equality_comparison_p - && 0 != (tem = simplify_binary_operation (XOR, mode, - XEXP (op0, 1), op1))) - { - op0 = XEXP (op0, 0); - op1 = tem; - continue; - } - break; - - case EQ: case NE: - case LT: case LTU: case LE: case LEU: - case GT: case GTU: case GE: case GEU: - /* We can't do anything if OP0 is a condition code value, rather - than an actual data value. */ - if (const_op != 0 -#ifdef HAVE_cc0 - || XEXP (op0, 0) == cc0_rtx -#endif - || GET_MODE_CLASS (GET_MODE (XEXP (op0, 0))) == MODE_CC) - break; - - /* Get the two operands being compared. */ - if (GET_CODE (XEXP (op0, 0)) == COMPARE) - tem = XEXP (XEXP (op0, 0), 0), tem1 = XEXP (XEXP (op0, 0), 1); - else - tem = XEXP (op0, 0), tem1 = XEXP (op0, 1); - - /* Check for the cases where we simply want the result of the - earlier test or the opposite of that result. */ - if (code == NE - || (code == EQ && reversible_comparison_p (op0)) - || (GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT - && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT - && (STORE_FLAG_VALUE - & (((HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (GET_MODE (op0)) - 1)))) - && (code == LT - || (code == GE && reversible_comparison_p (op0))))) - { - code = (code == LT || code == NE - ? GET_CODE (op0) : reverse_condition (GET_CODE (op0))); - op0 = tem, op1 = tem1; - continue; - } - break; - - case IOR: - /* The sign bit of (ior (plus X (const_int -1)) X) is non-zero - iff X <= 0. */ - if (sign_bit_comparison_p && GET_CODE (XEXP (op0, 0)) == PLUS - && XEXP (XEXP (op0, 0), 1) == constm1_rtx - && rtx_equal_p (XEXP (XEXP (op0, 0), 0), XEXP (op0, 1))) - { - op0 = XEXP (op0, 1); - code = (code == GE ? GT : LE); - continue; - } - break; - - case AND: - /* Convert (and (xshift 1 X) Y) to (and (lshiftrt Y X) 1). This - will be converted to a ZERO_EXTRACT later. */ - if (const_op == 0 && equality_comparison_p - && GET_CODE (XEXP (op0, 0)) == ASHIFT - && XEXP (XEXP (op0, 0), 0) == const1_rtx) - { - op0 = simplify_and_const_int - (op0, mode, gen_rtx_combine (LSHIFTRT, mode, - XEXP (op0, 1), - XEXP (XEXP (op0, 0), 1)), - (HOST_WIDE_INT) 1); - continue; - } - - /* If we are comparing (and (lshiftrt X C1) C2) for equality with - zero and X is a comparison and C1 and C2 describe only bits set - in STORE_FLAG_VALUE, we can compare with X. */ - if (const_op == 0 && equality_comparison_p - && mode_width <= HOST_BITS_PER_WIDE_INT - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && GET_CODE (XEXP (op0, 0)) == LSHIFTRT - && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (op0, 0), 1)) >= 0 - && INTVAL (XEXP (XEXP (op0, 0), 1)) < HOST_BITS_PER_WIDE_INT) - { - mask = ((INTVAL (XEXP (op0, 1)) & GET_MODE_MASK (mode)) - << INTVAL (XEXP (XEXP (op0, 0), 1))); - if ((~ STORE_FLAG_VALUE & mask) == 0 - && (GET_RTX_CLASS (GET_CODE (XEXP (XEXP (op0, 0), 0))) == '<' - || ((tem = get_last_value (XEXP (XEXP (op0, 0), 0))) != 0 - && GET_RTX_CLASS (GET_CODE (tem)) == '<'))) - { - op0 = XEXP (XEXP (op0, 0), 0); - continue; - } - } - - /* If we are doing an equality comparison of an AND of a bit equal - to the sign bit, replace this with a LT or GE comparison of - the underlying value. */ - if (equality_comparison_p - && const_op == 0 - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && mode_width <= HOST_BITS_PER_WIDE_INT - && ((INTVAL (XEXP (op0, 1)) & GET_MODE_MASK (mode)) - == (unsigned HOST_WIDE_INT) 1 << (mode_width - 1))) - { - op0 = XEXP (op0, 0); - code = (code == EQ ? GE : LT); - continue; - } - - /* If this AND operation is really a ZERO_EXTEND from a narrower - mode, the constant fits within that mode, and this is either an - equality or unsigned comparison, try to do this comparison in - the narrower mode. */ - if ((equality_comparison_p || unsigned_comparison_p) - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && (i = exact_log2 ((INTVAL (XEXP (op0, 1)) - & GET_MODE_MASK (mode)) - + 1)) >= 0 - && const_op >> i == 0 - && (tmode = mode_for_size (i, MODE_INT, 1)) != BLKmode) - { - op0 = gen_lowpart_for_combine (tmode, XEXP (op0, 0)); - continue; - } - - /* If this is (and:M1 (subreg:M2 X 0) (const_int C1)) where C1 fits - in both M1 and M2 and the SUBREG is either paradoxical or - represents the low part, permute the SUBREG and the AND and - try again. */ - if (GET_CODE (XEXP (op0, 0)) == SUBREG - && ((mode_width - >= GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (XEXP (op0, 0))))) -#ifdef WORD_REGISTER_OPERATIONS - || subreg_lowpart_p (XEXP (op0, 0)) -#endif - ) -#ifndef WORD_REGISTER_OPERATIONS - /* It is unsafe to commute the AND into the SUBREG if the SUBREG - is paradoxical and WORD_REGISTER_OPERATIONS is not defined. - As originally written the upper bits have a defined value - due to the AND operation. However, if we commute the AND - inside the SUBREG then they no longer have defined values - and the meaning of the code has been changed. */ - && (GET_MODE_SIZE (GET_MODE (XEXP (op0, 0))) - <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (op0, 0))))) -#endif - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && mode_width <= HOST_BITS_PER_WIDE_INT - && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (XEXP (op0, 0)))) - <= HOST_BITS_PER_WIDE_INT) - && (INTVAL (XEXP (op0, 1)) & ~ mask) == 0 - && 0 == (~ GET_MODE_MASK (GET_MODE (SUBREG_REG (XEXP (op0, 0)))) - & INTVAL (XEXP (op0, 1))) - && (unsigned HOST_WIDE_INT) INTVAL (XEXP (op0, 1)) != mask - && ((unsigned HOST_WIDE_INT) INTVAL (XEXP (op0, 1)) - != GET_MODE_MASK (GET_MODE (SUBREG_REG (XEXP (op0, 0)))))) - - { - op0 - = gen_lowpart_for_combine - (mode, - gen_binary (AND, GET_MODE (SUBREG_REG (XEXP (op0, 0))), - SUBREG_REG (XEXP (op0, 0)), XEXP (op0, 1))); - continue; - } - - break; - - case ASHIFT: - /* If we have (compare (ashift FOO N) (const_int C)) and - the high order N bits of FOO (N+1 if an inequality comparison) - are known to be zero, we can do this by comparing FOO with C - shifted right N bits so long as the low-order N bits of C are - zero. */ - if (GET_CODE (XEXP (op0, 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) >= 0 - && ((INTVAL (XEXP (op0, 1)) + ! equality_comparison_p) - < HOST_BITS_PER_WIDE_INT) - && ((const_op - & (((HOST_WIDE_INT) 1 << INTVAL (XEXP (op0, 1))) - 1)) == 0) - && mode_width <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (XEXP (op0, 0), mode) - & ~ (mask >> (INTVAL (XEXP (op0, 1)) - + ! equality_comparison_p))) == 0) - { - const_op >>= INTVAL (XEXP (op0, 1)); - op1 = GEN_INT (const_op); - op0 = XEXP (op0, 0); - continue; - } - - /* If we are doing a sign bit comparison, it means we are testing - a particular bit. Convert it to the appropriate AND. */ - if (sign_bit_comparison_p && GET_CODE (XEXP (op0, 1)) == CONST_INT - && mode_width <= HOST_BITS_PER_WIDE_INT) - { - op0 = simplify_and_const_int (NULL_RTX, mode, XEXP (op0, 0), - ((HOST_WIDE_INT) 1 - << (mode_width - 1 - - INTVAL (XEXP (op0, 1))))); - code = (code == LT ? NE : EQ); - continue; - } - - /* If this an equality comparison with zero and we are shifting - the low bit to the sign bit, we can convert this to an AND of the - low-order bit. */ - if (const_op == 0 && equality_comparison_p - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) == mode_width - 1) - { - op0 = simplify_and_const_int (NULL_RTX, mode, XEXP (op0, 0), - (HOST_WIDE_INT) 1); - continue; - } - break; - - case ASHIFTRT: - /* If this is an equality comparison with zero, we can do this - as a logical shift, which might be much simpler. */ - if (equality_comparison_p && const_op == 0 - && GET_CODE (XEXP (op0, 1)) == CONST_INT) - { - op0 = simplify_shift_const (NULL_RTX, LSHIFTRT, mode, - XEXP (op0, 0), - INTVAL (XEXP (op0, 1))); - continue; - } - - /* If OP0 is a sign extension and CODE is not an unsigned comparison, - do the comparison in a narrower mode. */ - if (! unsigned_comparison_p - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && GET_CODE (XEXP (op0, 0)) == ASHIFT - && XEXP (op0, 1) == XEXP (XEXP (op0, 0), 1) - && (tmode = mode_for_size (mode_width - INTVAL (XEXP (op0, 1)), - MODE_INT, 1)) != BLKmode - && ((unsigned HOST_WIDE_INT) const_op <= GET_MODE_MASK (tmode) - || ((unsigned HOST_WIDE_INT) - const_op - <= GET_MODE_MASK (tmode)))) - { - op0 = gen_lowpart_for_combine (tmode, XEXP (XEXP (op0, 0), 0)); - continue; - } - - /* ... fall through ... */ - case LSHIFTRT: - /* If we have (compare (xshiftrt FOO N) (const_int C)) and - the low order N bits of FOO are known to be zero, we can do this - by comparing FOO with C shifted left N bits so long as no - overflow occurs. */ - if (GET_CODE (XEXP (op0, 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) >= 0 - && INTVAL (XEXP (op0, 1)) < HOST_BITS_PER_WIDE_INT - && mode_width <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (XEXP (op0, 0), mode) - & (((HOST_WIDE_INT) 1 << INTVAL (XEXP (op0, 1))) - 1)) == 0 - && (const_op == 0 - || (floor_log2 (const_op) + INTVAL (XEXP (op0, 1)) - < mode_width))) - { - const_op <<= INTVAL (XEXP (op0, 1)); - op1 = GEN_INT (const_op); - op0 = XEXP (op0, 0); - continue; - } - - /* If we are using this shift to extract just the sign bit, we - can replace this with an LT or GE comparison. */ - if (const_op == 0 - && (equality_comparison_p || sign_bit_comparison_p) - && GET_CODE (XEXP (op0, 1)) == CONST_INT - && INTVAL (XEXP (op0, 1)) == mode_width - 1) - { - op0 = XEXP (op0, 0); - code = (code == NE || code == GT ? LT : GE); - continue; - } - break; - - default: - break; - } - - break; - } - - /* Now make any compound operations involved in this comparison. Then, - check for an outmost SUBREG on OP0 that is not doing anything or is - paradoxical. The latter case can only occur when it is known that the - "extra" bits will be zero. Therefore, it is safe to remove the SUBREG. - We can never remove a SUBREG for a non-equality comparison because the - sign bit is in a different place in the underlying object. */ - - op0 = make_compound_operation (op0, op1 == const0_rtx ? COMPARE : SET); - op1 = make_compound_operation (op1, SET); - - if (GET_CODE (op0) == SUBREG && subreg_lowpart_p (op0) - && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT - && (code == NE || code == EQ) - && ((GET_MODE_SIZE (GET_MODE (op0)) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))) - { - op0 = SUBREG_REG (op0); - op1 = gen_lowpart_for_combine (GET_MODE (op0), op1); - } - - else if (GET_CODE (op0) == SUBREG && subreg_lowpart_p (op0) - && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT - && (code == NE || code == EQ) - && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0))) - <= HOST_BITS_PER_WIDE_INT) - && (nonzero_bits (SUBREG_REG (op0), GET_MODE (SUBREG_REG (op0))) - & ~ GET_MODE_MASK (GET_MODE (op0))) == 0 - && (tem = gen_lowpart_for_combine (GET_MODE (SUBREG_REG (op0)), - op1), - (nonzero_bits (tem, GET_MODE (SUBREG_REG (op0))) - & ~ GET_MODE_MASK (GET_MODE (op0))) == 0)) - op0 = SUBREG_REG (op0), op1 = tem; - - /* We now do the opposite procedure: Some machines don't have compare - insns in all modes. If OP0's mode is an integer mode smaller than a - word and we can't do a compare in that mode, see if there is a larger - mode for which we can do the compare. There are a number of cases in - which we can use the wider mode. */ - - mode = GET_MODE (op0); - if (mode != VOIDmode && GET_MODE_CLASS (mode) == MODE_INT - && GET_MODE_SIZE (mode) < UNITS_PER_WORD - && cmp_optab->handlers[(int) mode].insn_code == CODE_FOR_nothing) - for (tmode = GET_MODE_WIDER_MODE (mode); - (tmode != VOIDmode - && GET_MODE_BITSIZE (tmode) <= HOST_BITS_PER_WIDE_INT); - tmode = GET_MODE_WIDER_MODE (tmode)) - if (cmp_optab->handlers[(int) tmode].insn_code != CODE_FOR_nothing) - { - /* If the only nonzero bits in OP0 and OP1 are those in the - narrower mode and this is an equality or unsigned comparison, - we can use the wider mode. Similarly for sign-extended - values, in which case it is true for all comparisons. */ - if (((code == EQ || code == NE - || code == GEU || code == GTU || code == LEU || code == LTU) - && (nonzero_bits (op0, tmode) & ~ GET_MODE_MASK (mode)) == 0 - && (nonzero_bits (op1, tmode) & ~ GET_MODE_MASK (mode)) == 0) - || ((num_sign_bit_copies (op0, tmode) - > GET_MODE_BITSIZE (tmode) - GET_MODE_BITSIZE (mode)) - && (num_sign_bit_copies (op1, tmode) - > GET_MODE_BITSIZE (tmode) - GET_MODE_BITSIZE (mode)))) - { - op0 = gen_lowpart_for_combine (tmode, op0); - op1 = gen_lowpart_for_combine (tmode, op1); - break; - } - - /* If this is a test for negative, we can make an explicit - test of the sign bit. */ - - if (op1 == const0_rtx && (code == LT || code == GE) - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) - { - op0 = gen_binary (AND, tmode, - gen_lowpart_for_combine (tmode, op0), - GEN_INT ((HOST_WIDE_INT) 1 - << (GET_MODE_BITSIZE (mode) - 1))); - code = (code == LT) ? NE : EQ; - break; - } - } - -#ifdef CANONICALIZE_COMPARISON - /* If this machine only supports a subset of valid comparisons, see if we - can convert an unsupported one into a supported one. */ - CANONICALIZE_COMPARISON (code, op0, op1); -#endif - - *pop0 = op0; - *pop1 = op1; - - return code; -} - -/* Return 1 if we know that X, a comparison operation, is not operating - on a floating-point value or is EQ or NE, meaning that we can safely - reverse it. */ - -static int -reversible_comparison_p (x) - rtx x; -{ - if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT - || flag_fast_math - || GET_CODE (x) == NE || GET_CODE (x) == EQ) - return 1; - - switch (GET_MODE_CLASS (GET_MODE (XEXP (x, 0)))) - { - case MODE_INT: - case MODE_PARTIAL_INT: - case MODE_COMPLEX_INT: - return 1; - - case MODE_CC: - /* If the mode of the condition codes tells us that this is safe, - we need look no further. */ - if (REVERSIBLE_CC_MODE (GET_MODE (XEXP (x, 0)))) - return 1; - - /* Otherwise try and find where the condition codes were last set and - use that. */ - x = get_last_value (XEXP (x, 0)); - return (x && GET_CODE (x) == COMPARE - && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0)))); - - default: - return 0; - } -} - -/* Utility function for following routine. Called when X is part of a value - being stored into reg_last_set_value. Sets reg_last_set_table_tick - for each register mentioned. Similar to mention_regs in cse.c */ - -static void -update_table_tick (x) - rtx x; -{ - register enum rtx_code code = GET_CODE (x); - register char *fmt = GET_RTX_FORMAT (code); - register int i; - - if (code == REG) - { - int regno = REGNO (x); - int endregno = regno + (regno < FIRST_PSEUDO_REGISTER - ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1); - - for (i = regno; i < endregno; i++) - reg_last_set_table_tick[i] = label_tick; - - return; - } - - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - /* Note that we can't have an "E" in values stored; see - get_last_value_validate. */ - if (fmt[i] == 'e') - update_table_tick (XEXP (x, i)); -} - -/* Record that REG is set to VALUE in insn INSN. If VALUE is zero, we - are saying that the register is clobbered and we no longer know its - value. If INSN is zero, don't update reg_last_set; this is only permitted - with VALUE also zero and is used to invalidate the register. */ - -static void -record_value_for_reg (reg, insn, value) - rtx reg; - rtx insn; - rtx value; -{ - int regno = REGNO (reg); - int endregno = regno + (regno < FIRST_PSEUDO_REGISTER - ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1); - int i; - - /* If VALUE contains REG and we have a previous value for REG, substitute - the previous value. */ - if (value && insn && reg_overlap_mentioned_p (reg, value)) - { - rtx tem; - - /* Set things up so get_last_value is allowed to see anything set up to - our insn. */ - subst_low_cuid = INSN_CUID (insn); - tem = get_last_value (reg); - - if (tem) - value = replace_rtx (copy_rtx (value), reg, tem); - } - - /* For each register modified, show we don't know its value, that - we don't know about its bitwise content, that its value has been - updated, and that we don't know the location of the death of the - register. */ - for (i = regno; i < endregno; i ++) - { - if (insn) - reg_last_set[i] = insn; - reg_last_set_value[i] = 0; - reg_last_set_mode[i] = 0; - reg_last_set_nonzero_bits[i] = 0; - reg_last_set_sign_bit_copies[i] = 0; - reg_last_death[i] = 0; - } - - /* Mark registers that are being referenced in this value. */ - if (value) - update_table_tick (value); - - /* Now update the status of each register being set. - If someone is using this register in this block, set this register - to invalid since we will get confused between the two lives in this - basic block. This makes using this register always invalid. In cse, we - scan the table to invalidate all entries using this register, but this - is too much work for us. */ - - for (i = regno; i < endregno; i++) - { - reg_last_set_label[i] = label_tick; - if (value && reg_last_set_table_tick[i] == label_tick) - reg_last_set_invalid[i] = 1; - else - reg_last_set_invalid[i] = 0; - } - - /* The value being assigned might refer to X (like in "x++;"). In that - case, we must replace it with (clobber (const_int 0)) to prevent - infinite loops. */ - if (value && ! get_last_value_validate (&value, insn, - reg_last_set_label[regno], 0)) - { - value = copy_rtx (value); - if (! get_last_value_validate (&value, insn, - reg_last_set_label[regno], 1)) - value = 0; - } - - /* For the main register being modified, update the value, the mode, the - nonzero bits, and the number of sign bit copies. */ - - reg_last_set_value[regno] = value; - - if (value) - { - subst_low_cuid = INSN_CUID (insn); - reg_last_set_mode[regno] = GET_MODE (reg); - reg_last_set_nonzero_bits[regno] = nonzero_bits (value, GET_MODE (reg)); - reg_last_set_sign_bit_copies[regno] - = num_sign_bit_copies (value, GET_MODE (reg)); - } -} - -/* Used for communication between the following two routines. */ -static rtx record_dead_insn; - -/* Called via note_stores from record_dead_and_set_regs to handle one - SET or CLOBBER in an insn. */ - -static void -record_dead_and_set_regs_1 (dest, setter) - rtx dest, setter; -{ - if (GET_CODE (dest) == SUBREG) - dest = SUBREG_REG (dest); - - if (GET_CODE (dest) == REG) - { - /* If we are setting the whole register, we know its value. Otherwise - show that we don't know the value. We can handle SUBREG in - some cases. */ - if (GET_CODE (setter) == SET && dest == SET_DEST (setter)) - record_value_for_reg (dest, record_dead_insn, SET_SRC (setter)); - else if (GET_CODE (setter) == SET - && GET_CODE (SET_DEST (setter)) == SUBREG - && SUBREG_REG (SET_DEST (setter)) == dest - && GET_MODE_BITSIZE (GET_MODE (dest)) <= BITS_PER_WORD - && subreg_lowpart_p (SET_DEST (setter))) - record_value_for_reg (dest, record_dead_insn, - gen_lowpart_for_combine (GET_MODE (dest), - SET_SRC (setter))); - else - record_value_for_reg (dest, record_dead_insn, NULL_RTX); - } - else if (GET_CODE (dest) == MEM - /* Ignore pushes, they clobber nothing. */ - && ! push_operand (dest, GET_MODE (dest))) - mem_last_set = INSN_CUID (record_dead_insn); -} - -/* Update the records of when each REG was most recently set or killed - for the things done by INSN. This is the last thing done in processing - INSN in the combiner loop. - - We update reg_last_set, reg_last_set_value, reg_last_set_mode, - reg_last_set_nonzero_bits, reg_last_set_sign_bit_copies, reg_last_death, - and also the similar information mem_last_set (which insn most recently - modified memory) and last_call_cuid (which insn was the most recent - subroutine call). */ - -static void -record_dead_and_set_regs (insn) - rtx insn; -{ - register rtx link; - int i; - - for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) - { - if (REG_NOTE_KIND (link) == REG_DEAD - && GET_CODE (XEXP (link, 0)) == REG) - { - int regno = REGNO (XEXP (link, 0)); - int endregno - = regno + (regno < FIRST_PSEUDO_REGISTER - ? HARD_REGNO_NREGS (regno, GET_MODE (XEXP (link, 0))) - : 1); - - for (i = regno; i < endregno; i++) - reg_last_death[i] = insn; - } - else if (REG_NOTE_KIND (link) == REG_INC) - record_value_for_reg (XEXP (link, 0), insn, NULL_RTX); - } - - if (GET_CODE (insn) == CALL_INSN) - { - for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) - if (call_used_regs[i]) - { - reg_last_set_value[i] = 0; - reg_last_set_mode[i] = 0; - reg_last_set_nonzero_bits[i] = 0; - reg_last_set_sign_bit_copies[i] = 0; - reg_last_death[i] = 0; - } - - last_call_cuid = mem_last_set = INSN_CUID (insn); - } - - record_dead_insn = insn; - note_stores (PATTERN (insn), record_dead_and_set_regs_1); -} - -/* Utility routine for the following function. Verify that all the registers - mentioned in *LOC are valid when *LOC was part of a value set when - label_tick == TICK. Return 0 if some are not. - - If REPLACE is non-zero, replace the invalid reference with - (clobber (const_int 0)) and return 1. This replacement is useful because - we often can get useful information about the form of a value (e.g., if - it was produced by a shift that always produces -1 or 0) even though - we don't know exactly what registers it was produced from. */ - -static int -get_last_value_validate (loc, insn, tick, replace) - rtx *loc; - rtx insn; - int tick; - int replace; -{ - rtx x = *loc; - char *fmt = GET_RTX_FORMAT (GET_CODE (x)); - int len = GET_RTX_LENGTH (GET_CODE (x)); - int i; - - if (GET_CODE (x) == REG) - { - int regno = REGNO (x); - int endregno = regno + (regno < FIRST_PSEUDO_REGISTER - ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1); - int j; - - for (j = regno; j < endregno; j++) - if (reg_last_set_invalid[j] - /* If this is a pseudo-register that was only set once, it is - always valid. */ - || (! (regno >= FIRST_PSEUDO_REGISTER && REG_N_SETS (regno) == 1) - && reg_last_set_label[j] > tick)) - { - if (replace) - *loc = gen_rtx_CLOBBER (GET_MODE (x), const0_rtx); - return replace; - } - - return 1; - } - /* If this is a memory reference, make sure that there were - no stores after it that might have clobbered the value. We don't - have alias info, so we assume any store invalidates it. */ - else if (GET_CODE (x) == MEM && ! RTX_UNCHANGING_P (x) - && INSN_CUID (insn) <= mem_last_set) - { - if (replace) - *loc = gen_rtx_CLOBBER (GET_MODE (x), const0_rtx); - return replace; - } - - for (i = 0; i < len; i++) - if ((fmt[i] == 'e' - && get_last_value_validate (&XEXP (x, i), insn, tick, replace) == 0) - /* Don't bother with these. They shouldn't occur anyway. */ - || fmt[i] == 'E') - return 0; - - /* If we haven't found a reason for it to be invalid, it is valid. */ - return 1; -} - -/* Get the last value assigned to X, if known. Some registers - in the value may be replaced with (clobber (const_int 0)) if their value - is known longer known reliably. */ - -static rtx -get_last_value (x) - rtx x; -{ - int regno; - rtx value; - - /* If this is a non-paradoxical SUBREG, get the value of its operand and - then convert it to the desired mode. If this is a paradoxical SUBREG, - we cannot predict what values the "extra" bits might have. */ - if (GET_CODE (x) == SUBREG - && subreg_lowpart_p (x) - && (GET_MODE_SIZE (GET_MODE (x)) - <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) - && (value = get_last_value (SUBREG_REG (x))) != 0) - return gen_lowpart_for_combine (GET_MODE (x), value); - - if (GET_CODE (x) != REG) - return 0; - - regno = REGNO (x); - value = reg_last_set_value[regno]; - - /* If we don't have a value or if it isn't for this basic block, - return 0. */ - - if (value == 0 - || (REG_N_SETS (regno) != 1 - && reg_last_set_label[regno] != label_tick)) - return 0; - - /* If the value was set in a later insn than the ones we are processing, - we can't use it even if the register was only set once. */ - if (INSN_CUID (reg_last_set[regno]) >= subst_low_cuid) - return 0; - - /* If the value has all its registers valid, return it. */ - if (get_last_value_validate (&value, reg_last_set[regno], - reg_last_set_label[regno], 0)) - return value; - - /* Otherwise, make a copy and replace any invalid register with - (clobber (const_int 0)). If that fails for some reason, return 0. */ - - value = copy_rtx (value); - if (get_last_value_validate (&value, reg_last_set[regno], - reg_last_set_label[regno], 1)) - return value; - - return 0; -} - -/* Return nonzero if expression X refers to a REG or to memory - that is set in an instruction more recent than FROM_CUID. */ - -static int -use_crosses_set_p (x, from_cuid) - register rtx x; - int from_cuid; -{ - register char *fmt; - register int i; - register enum rtx_code code = GET_CODE (x); - - if (code == REG) - { - register int regno = REGNO (x); - int endreg = regno + (regno < FIRST_PSEUDO_REGISTER - ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1); - -#ifdef PUSH_ROUNDING - /* Don't allow uses of the stack pointer to be moved, - because we don't know whether the move crosses a push insn. */ - if (regno == STACK_POINTER_REGNUM) - return 1; -#endif - for (;regno < endreg; regno++) - if (reg_last_set[regno] - && INSN_CUID (reg_last_set[regno]) > from_cuid) - return 1; - return 0; - } - - if (code == MEM && mem_last_set > from_cuid) - return 1; - - fmt = GET_RTX_FORMAT (code); - - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - if (fmt[i] == 'E') - { - register int j; - for (j = XVECLEN (x, i) - 1; j >= 0; j--) - if (use_crosses_set_p (XVECEXP (x, i, j), from_cuid)) - return 1; - } - else if (fmt[i] == 'e' - && use_crosses_set_p (XEXP (x, i), from_cuid)) - return 1; - } - return 0; -} - -/* Define three variables used for communication between the following - routines. */ - -static int reg_dead_regno, reg_dead_endregno; -static int reg_dead_flag; - -/* Function called via note_stores from reg_dead_at_p. - - If DEST is within [reg_dead_regno, reg_dead_endregno), set - reg_dead_flag to 1 if X is a CLOBBER and to -1 it is a SET. */ - -static void -reg_dead_at_p_1 (dest, x) - rtx dest; - rtx x; -{ - int regno, endregno; - - if (GET_CODE (dest) != REG) - return; - - regno = REGNO (dest); - endregno = regno + (regno < FIRST_PSEUDO_REGISTER - ? HARD_REGNO_NREGS (regno, GET_MODE (dest)) : 1); - - if (reg_dead_endregno > regno && reg_dead_regno < endregno) - reg_dead_flag = (GET_CODE (x) == CLOBBER) ? 1 : -1; -} - -/* Return non-zero if REG is known to be dead at INSN. - - We scan backwards from INSN. If we hit a REG_DEAD note or a CLOBBER - referencing REG, it is dead. If we hit a SET referencing REG, it is - live. Otherwise, see if it is live or dead at the start of the basic - block we are in. Hard regs marked as being live in NEWPAT_USED_REGS - must be assumed to be always live. */ - -static int -reg_dead_at_p (reg, insn) - rtx reg; - rtx insn; -{ - int block, i; - - /* Set variables for reg_dead_at_p_1. */ - reg_dead_regno = REGNO (reg); - reg_dead_endregno = reg_dead_regno + (reg_dead_regno < FIRST_PSEUDO_REGISTER - ? HARD_REGNO_NREGS (reg_dead_regno, - GET_MODE (reg)) - : 1); - - reg_dead_flag = 0; - - /* Check that reg isn't mentioned in NEWPAT_USED_REGS. */ - if (reg_dead_regno < FIRST_PSEUDO_REGISTER) - { - for (i = reg_dead_regno; i < reg_dead_endregno; i++) - if (TEST_HARD_REG_BIT (newpat_used_regs, i)) - return 0; - } - - /* Scan backwards until we find a REG_DEAD note, SET, CLOBBER, label, or - beginning of function. */ - for (; insn && GET_CODE (insn) != CODE_LABEL && GET_CODE (insn) != BARRIER; - insn = prev_nonnote_insn (insn)) - { - note_stores (PATTERN (insn), reg_dead_at_p_1); - if (reg_dead_flag) - return reg_dead_flag == 1 ? 1 : 0; - - if (find_regno_note (insn, REG_DEAD, reg_dead_regno)) - return 1; - } - - /* Get the basic block number that we were in. */ - if (insn == 0) - block = 0; - else - { - for (block = 0; block < n_basic_blocks; block++) - if (insn == BLOCK_HEAD (block)) - break; - - if (block == n_basic_blocks) - return 0; - } - - for (i = reg_dead_regno; i < reg_dead_endregno; i++) - if (REGNO_REG_SET_P (BASIC_BLOCK (block)->global_live_at_start, i)) - return 0; - - return 1; -} - -/* Note hard registers in X that are used. This code is similar to - that in flow.c, but much simpler since we don't care about pseudos. */ - -static void -mark_used_regs_combine (x) - rtx x; -{ - register RTX_CODE code = GET_CODE (x); - register int regno; - int i; - - switch (code) - { - case LABEL_REF: - case SYMBOL_REF: - case CONST_INT: - case CONST: - case CONST_DOUBLE: - case PC: - case ADDR_VEC: - case ADDR_DIFF_VEC: - case ASM_INPUT: -#ifdef HAVE_cc0 - /* CC0 must die in the insn after it is set, so we don't need to take - special note of it here. */ - case CC0: -#endif - return; - - case CLOBBER: - /* If we are clobbering a MEM, mark any hard registers inside the - address as used. */ - if (GET_CODE (XEXP (x, 0)) == MEM) - mark_used_regs_combine (XEXP (XEXP (x, 0), 0)); - return; - - case REG: - regno = REGNO (x); - /* A hard reg in a wide mode may really be multiple registers. - If so, mark all of them just like the first. */ - if (regno < FIRST_PSEUDO_REGISTER) - { - /* None of this applies to the stack, frame or arg pointers */ - if (regno == STACK_POINTER_REGNUM -#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM - || regno == HARD_FRAME_POINTER_REGNUM -#endif -#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM - || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) -#endif - || regno == FRAME_POINTER_REGNUM) - return; - - i = HARD_REGNO_NREGS (regno, GET_MODE (x)); - while (i-- > 0) - SET_HARD_REG_BIT (newpat_used_regs, regno + i); - } - return; - - case SET: - { - /* If setting a MEM, or a SUBREG of a MEM, then note any hard regs in - the address. */ - register rtx testreg = SET_DEST (x); - - while (GET_CODE (testreg) == SUBREG - || GET_CODE (testreg) == ZERO_EXTRACT - || GET_CODE (testreg) == SIGN_EXTRACT - || GET_CODE (testreg) == STRICT_LOW_PART) - testreg = XEXP (testreg, 0); - - if (GET_CODE (testreg) == MEM) - mark_used_regs_combine (XEXP (testreg, 0)); - - mark_used_regs_combine (SET_SRC (x)); - } - return; - - default: - break; - } - - /* Recursively scan the operands of this expression. */ - - { - register char *fmt = GET_RTX_FORMAT (code); - - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - if (fmt[i] == 'e') - mark_used_regs_combine (XEXP (x, i)); - else if (fmt[i] == 'E') - { - register int j; - - for (j = 0; j < XVECLEN (x, i); j++) - mark_used_regs_combine (XVECEXP (x, i, j)); - } - } - } -} - - -/* Remove register number REGNO from the dead registers list of INSN. - - Return the note used to record the death, if there was one. */ - -rtx -remove_death (regno, insn) - int regno; - rtx insn; -{ - register rtx note = find_regno_note (insn, REG_DEAD, regno); - - if (note) - { - REG_N_DEATHS (regno)--; - remove_note (insn, note); - } - - return note; -} - -/* For each register (hardware or pseudo) used within expression X, if its - death is in an instruction with cuid between FROM_CUID (inclusive) and - TO_INSN (exclusive), put a REG_DEAD note for that register in the - list headed by PNOTES. - - That said, don't move registers killed by maybe_kill_insn. - - This is done when X is being merged by combination into TO_INSN. These - notes will then be distributed as needed. */ - -static void -move_deaths (x, maybe_kill_insn, from_cuid, to_insn, pnotes) - rtx x; - rtx maybe_kill_insn; - int from_cuid; - rtx to_insn; - rtx *pnotes; -{ - register char *fmt; - register int len, i; - register enum rtx_code code = GET_CODE (x); - - if (code == REG) - { - register int regno = REGNO (x); - register rtx where_dead = reg_last_death[regno]; - register rtx before_dead, after_dead; - - /* Don't move the register if it gets killed in between from and to */ - if (maybe_kill_insn && reg_set_p (x, maybe_kill_insn) - && !reg_referenced_p (x, maybe_kill_insn)) - return; - - /* WHERE_DEAD could be a USE insn made by combine, so first we - make sure that we have insns with valid INSN_CUID values. */ - before_dead = where_dead; - while (before_dead && INSN_UID (before_dead) > max_uid_cuid) - before_dead = PREV_INSN (before_dead); - after_dead = where_dead; - while (after_dead && INSN_UID (after_dead) > max_uid_cuid) - after_dead = NEXT_INSN (after_dead); - - if (before_dead && after_dead - && INSN_CUID (before_dead) >= from_cuid - && (INSN_CUID (after_dead) < INSN_CUID (to_insn) - || (where_dead != after_dead - && INSN_CUID (after_dead) == INSN_CUID (to_insn)))) - { - rtx note = remove_death (regno, where_dead); - - /* It is possible for the call above to return 0. This can occur - when reg_last_death points to I2 or I1 that we combined with. - In that case make a new note. - - We must also check for the case where X is a hard register - and NOTE is a death note for a range of hard registers - including X. In that case, we must put REG_DEAD notes for - the remaining registers in place of NOTE. */ - - if (note != 0 && regno < FIRST_PSEUDO_REGISTER - && (GET_MODE_SIZE (GET_MODE (XEXP (note, 0))) - > GET_MODE_SIZE (GET_MODE (x)))) - { - int deadregno = REGNO (XEXP (note, 0)); - int deadend - = (deadregno + HARD_REGNO_NREGS (deadregno, - GET_MODE (XEXP (note, 0)))); - int ourend = regno + HARD_REGNO_NREGS (regno, GET_MODE (x)); - int i; - - for (i = deadregno; i < deadend; i++) - if (i < regno || i >= ourend) - REG_NOTES (where_dead) - = gen_rtx_EXPR_LIST (REG_DEAD, - gen_rtx_REG (reg_raw_mode[i], i), - REG_NOTES (where_dead)); - } - /* If we didn't find any note, or if we found a REG_DEAD note that - covers only part of the given reg, and we have a multi-reg hard - register, then to be safe we must check for REG_DEAD notes - for each register other than the first. They could have - their own REG_DEAD notes lying around. */ - else if ((note == 0 - || (note != 0 - && (GET_MODE_SIZE (GET_MODE (XEXP (note, 0))) - < GET_MODE_SIZE (GET_MODE (x))))) - && regno < FIRST_PSEUDO_REGISTER - && HARD_REGNO_NREGS (regno, GET_MODE (x)) > 1) - { - int ourend = regno + HARD_REGNO_NREGS (regno, GET_MODE (x)); - int i, offset; - rtx oldnotes = 0; - - if (note) - offset = HARD_REGNO_NREGS (regno, GET_MODE (XEXP (note, 0))); - else - offset = 1; - - for (i = regno + offset; i < ourend; i++) - move_deaths (gen_rtx_REG (reg_raw_mode[i], i), - maybe_kill_insn, from_cuid, to_insn, &oldnotes); - } - - if (note != 0 && GET_MODE (XEXP (note, 0)) == GET_MODE (x)) - { - XEXP (note, 1) = *pnotes; - *pnotes = note; - } - else - *pnotes = gen_rtx_EXPR_LIST (REG_DEAD, x, *pnotes); - - REG_N_DEATHS (regno)++; - } - - return; - } - - else if (GET_CODE (x) == SET) - { - rtx dest = SET_DEST (x); - - move_deaths (SET_SRC (x), maybe_kill_insn, from_cuid, to_insn, pnotes); - - /* In the case of a ZERO_EXTRACT, a STRICT_LOW_PART, or a SUBREG - that accesses one word of a multi-word item, some - piece of everything register in the expression is used by - this insn, so remove any old death. */ - - if (GET_CODE (dest) == ZERO_EXTRACT - || GET_CODE (dest) == STRICT_LOW_PART - || (GET_CODE (dest) == SUBREG - && (((GET_MODE_SIZE (GET_MODE (dest)) - + UNITS_PER_WORD - 1) / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) - + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))) - { - move_deaths (dest, maybe_kill_insn, from_cuid, to_insn, pnotes); - return; - } - - /* If this is some other SUBREG, we know it replaces the entire - value, so use that as the destination. */ - if (GET_CODE (dest) == SUBREG) - dest = SUBREG_REG (dest); - - /* If this is a MEM, adjust deaths of anything used in the address. - For a REG (the only other possibility), the entire value is - being replaced so the old value is not used in this insn. */ - - if (GET_CODE (dest) == MEM) - move_deaths (XEXP (dest, 0), maybe_kill_insn, from_cuid, - to_insn, pnotes); - return; - } - - else if (GET_CODE (x) == CLOBBER) - return; - - len = GET_RTX_LENGTH (code); - fmt = GET_RTX_FORMAT (code); - - for (i = 0; i < len; i++) - { - if (fmt[i] == 'E') - { - register int j; - for (j = XVECLEN (x, i) - 1; j >= 0; j--) - move_deaths (XVECEXP (x, i, j), maybe_kill_insn, from_cuid, - to_insn, pnotes); - } - else if (fmt[i] == 'e') - move_deaths (XEXP (x, i), maybe_kill_insn, from_cuid, to_insn, pnotes); - } -} - -/* Return 1 if X is the target of a bit-field assignment in BODY, the - pattern of an insn. X must be a REG. */ - -static int -reg_bitfield_target_p (x, body) - rtx x; - rtx body; -{ - int i; - - if (GET_CODE (body) == SET) - { - rtx dest = SET_DEST (body); - rtx target; - int regno, tregno, endregno, endtregno; - - if (GET_CODE (dest) == ZERO_EXTRACT) - target = XEXP (dest, 0); - else if (GET_CODE (dest) == STRICT_LOW_PART) - target = SUBREG_REG (XEXP (dest, 0)); - else - return 0; - - if (GET_CODE (target) == SUBREG) - target = SUBREG_REG (target); - - if (GET_CODE (target) != REG) - return 0; - - tregno = REGNO (target), regno = REGNO (x); - if (tregno >= FIRST_PSEUDO_REGISTER || regno >= FIRST_PSEUDO_REGISTER) - return target == x; - - endtregno = tregno + HARD_REGNO_NREGS (tregno, GET_MODE (target)); - endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x)); - - return endregno > tregno && regno < endtregno; - } - - else if (GET_CODE (body) == PARALLEL) - for (i = XVECLEN (body, 0) - 1; i >= 0; i--) - if (reg_bitfield_target_p (x, XVECEXP (body, 0, i))) - return 1; - - return 0; -} - -/* Given a chain of REG_NOTES originally from FROM_INSN, try to place them - as appropriate. I3 and I2 are the insns resulting from the combination - insns including FROM (I2 may be zero). - - ELIM_I2 and ELIM_I1 are either zero or registers that we know will - not need REG_DEAD notes because they are being substituted for. This - saves searching in the most common cases. - - Each note in the list is either ignored or placed on some insns, depending - on the type of note. */ - -static void -distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1) - rtx notes; - rtx from_insn; - rtx i3, i2; - rtx elim_i2, elim_i1; -{ - rtx note, next_note; - rtx tem; - - for (note = notes; note; note = next_note) - { - rtx place = 0, place2 = 0; - - /* If this NOTE references a pseudo register, ensure it references - the latest copy of that register. */ - if (XEXP (note, 0) && GET_CODE (XEXP (note, 0)) == REG - && REGNO (XEXP (note, 0)) >= FIRST_PSEUDO_REGISTER) - XEXP (note, 0) = regno_reg_rtx[REGNO (XEXP (note, 0))]; - - next_note = XEXP (note, 1); - switch (REG_NOTE_KIND (note)) - { - case REG_BR_PROB: - case REG_EXEC_COUNT: - /* Doesn't matter much where we put this, as long as it's somewhere. - It is preferable to keep these notes on branches, which is most - likely to be i3. */ - place = i3; - break; - - case REG_EH_REGION: - /* This note must remain with the call. It should not be possible - for both I2 and I3 to be a call. */ - if (GET_CODE (i3) == CALL_INSN) - place = i3; - else if (i2 && GET_CODE (i2) == CALL_INSN) - place = i2; - else - abort (); - break; - - case REG_UNUSED: - /* Any clobbers for i3 may still exist, and so we must process - REG_UNUSED notes from that insn. - - Any clobbers from i2 or i1 can only exist if they were added by - recog_for_combine. In that case, recog_for_combine created the - necessary REG_UNUSED notes. Trying to keep any original - REG_UNUSED notes from these insns can cause incorrect output - if it is for the same register as the original i3 dest. - In that case, we will notice that the register is set in i3, - and then add a REG_UNUSED note for the destination of i3, which - is wrong. However, it is possible to have REG_UNUSED notes from - i2 or i1 for register which were both used and clobbered, so - we keep notes from i2 or i1 if they will turn into REG_DEAD - notes. */ - - /* If this register is set or clobbered in I3, put the note there - unless there is one already. */ - if (reg_set_p (XEXP (note, 0), PATTERN (i3))) - { - if (from_insn != i3) - break; - - if (! (GET_CODE (XEXP (note, 0)) == REG - ? find_regno_note (i3, REG_UNUSED, REGNO (XEXP (note, 0))) - : find_reg_note (i3, REG_UNUSED, XEXP (note, 0)))) - place = i3; - } - /* Otherwise, if this register is used by I3, then this register - now dies here, so we must put a REG_DEAD note here unless there - is one already. */ - else if (reg_referenced_p (XEXP (note, 0), PATTERN (i3)) - && ! (GET_CODE (XEXP (note, 0)) == REG - ? find_regno_note (i3, REG_DEAD, REGNO (XEXP (note, 0))) - : find_reg_note (i3, REG_DEAD, XEXP (note, 0)))) - { - PUT_REG_NOTE_KIND (note, REG_DEAD); - place = i3; - } - break; - - case REG_EQUAL: - case REG_EQUIV: - case REG_NONNEG: - case REG_NOALIAS: - /* These notes say something about results of an insn. We can - only support them if they used to be on I3 in which case they - remain on I3. Otherwise they are ignored. - - If the note refers to an expression that is not a constant, we - must also ignore the note since we cannot tell whether the - equivalence is still true. It might be possible to do - slightly better than this (we only have a problem if I2DEST - or I1DEST is present in the expression), but it doesn't - seem worth the trouble. */ - - if (from_insn == i3 - && (XEXP (note, 0) == 0 || CONSTANT_P (XEXP (note, 0)))) - place = i3; - break; - - case REG_INC: - case REG_NO_CONFLICT: - /* These notes say something about how a register is used. They must - be present on any use of the register in I2 or I3. */ - if (reg_mentioned_p (XEXP (note, 0), PATTERN (i3))) - place = i3; - - if (i2 && reg_mentioned_p (XEXP (note, 0), PATTERN (i2))) - { - if (place) - place2 = i2; - else - place = i2; - } - break; - - case REG_LABEL: - /* This can show up in several ways -- either directly in the - pattern, or hidden off in the constant pool with (or without?) - a REG_EQUAL note. */ - /* ??? Ignore the without-reg_equal-note problem for now. */ - if (reg_mentioned_p (XEXP (note, 0), PATTERN (i3)) - || ((tem = find_reg_note (i3, REG_EQUAL, NULL_RTX)) - && GET_CODE (XEXP (tem, 0)) == LABEL_REF - && XEXP (XEXP (tem, 0), 0) == XEXP (note, 0))) - place = i3; - - if (i2 - && (reg_mentioned_p (XEXP (note, 0), PATTERN (i2)) - || ((tem = find_reg_note (i2, REG_EQUAL, NULL_RTX)) - && GET_CODE (XEXP (tem, 0)) == LABEL_REF - && XEXP (XEXP (tem, 0), 0) == XEXP (note, 0)))) - { - if (place) - place2 = i2; - else - place = i2; - } - break; - - case REG_WAS_0: - /* It is too much trouble to try to see if this note is still - correct in all situations. It is better to simply delete it. */ - break; - - case REG_RETVAL: - /* If the insn previously containing this note still exists, - put it back where it was. Otherwise move it to the previous - insn. Adjust the corresponding REG_LIBCALL note. */ - if (GET_CODE (from_insn) != NOTE) - place = from_insn; - else - { - tem = find_reg_note (XEXP (note, 0), REG_LIBCALL, NULL_RTX); - place = prev_real_insn (from_insn); - if (tem && place) - XEXP (tem, 0) = place; - } - break; - - case REG_LIBCALL: - /* This is handled similarly to REG_RETVAL. */ - if (GET_CODE (from_insn) != NOTE) - place = from_insn; - else - { - tem = find_reg_note (XEXP (note, 0), REG_RETVAL, NULL_RTX); - place = next_real_insn (from_insn); - if (tem && place) - XEXP (tem, 0) = place; - } - break; - - case REG_DEAD: - /* If the register is used as an input in I3, it dies there. - Similarly for I2, if it is non-zero and adjacent to I3. - - If the register is not used as an input in either I3 or I2 - and it is not one of the registers we were supposed to eliminate, - there are two possibilities. We might have a non-adjacent I2 - or we might have somehow eliminated an additional register - from a computation. For example, we might have had A & B where - we discover that B will always be zero. In this case we will - eliminate the reference to A. - - In both cases, we must search to see if we can find a previous - use of A and put the death note there. */ - - if (from_insn - && GET_CODE (from_insn) == CALL_INSN - && find_reg_fusage (from_insn, USE, XEXP (note, 0))) - place = from_insn; - else if (reg_referenced_p (XEXP (note, 0), PATTERN (i3))) - place = i3; - else if (i2 != 0 && next_nonnote_insn (i2) == i3 - && reg_referenced_p (XEXP (note, 0), PATTERN (i2))) - place = i2; - - if (XEXP (note, 0) == elim_i2 || XEXP (note, 0) == elim_i1) - break; - - /* If the register is used in both I2 and I3 and it dies in I3, - we might have added another reference to it. If reg_n_refs - was 2, bump it to 3. This has to be correct since the - register must have been set somewhere. The reason this is - done is because local-alloc.c treats 2 references as a - special case. */ - - if (place == i3 && i2 != 0 && GET_CODE (XEXP (note, 0)) == REG - && REG_N_REFS (REGNO (XEXP (note, 0)))== 2 - && reg_referenced_p (XEXP (note, 0), PATTERN (i2))) - REG_N_REFS (REGNO (XEXP (note, 0))) = 3; - - if (place == 0) - { - for (tem = prev_nonnote_insn (i3); - place == 0 && tem - && (GET_CODE (tem) == INSN || GET_CODE (tem) == CALL_INSN); - tem = prev_nonnote_insn (tem)) - { - /* If the register is being set at TEM, see if that is all - TEM is doing. If so, delete TEM. Otherwise, make this - into a REG_UNUSED note instead. */ - if (reg_set_p (XEXP (note, 0), PATTERN (tem))) - { - rtx set = single_set (tem); - rtx inner_dest = 0; -#ifdef HAVE_cc0 - rtx cc0_setter = NULL_RTX; -#endif - - if (set != 0) - for (inner_dest = SET_DEST (set); - GET_CODE (inner_dest) == STRICT_LOW_PART - || GET_CODE (inner_dest) == SUBREG - || GET_CODE (inner_dest) == ZERO_EXTRACT; - inner_dest = XEXP (inner_dest, 0)) - ; - - /* Verify that it was the set, and not a clobber that - modified the register. - - CC0 targets must be careful to maintain setter/user - pairs. If we cannot delete the setter due to side - effects, mark the user with an UNUSED note instead - of deleting it. */ - - if (set != 0 && ! side_effects_p (SET_SRC (set)) - && rtx_equal_p (XEXP (note, 0), inner_dest) -#ifdef HAVE_cc0 - && (! reg_mentioned_p (cc0_rtx, SET_SRC (set)) - || ((cc0_setter = prev_cc0_setter (tem)) != NULL - && sets_cc0_p (PATTERN (cc0_setter)) > 0)) -#endif - ) - { - /* Move the notes and links of TEM elsewhere. - This might delete other dead insns recursively. - First set the pattern to something that won't use - any register. */ - - PATTERN (tem) = pc_rtx; - - distribute_notes (REG_NOTES (tem), tem, tem, - NULL_RTX, NULL_RTX, NULL_RTX); - distribute_links (LOG_LINKS (tem)); - - PUT_CODE (tem, NOTE); - NOTE_LINE_NUMBER (tem) = NOTE_INSN_DELETED; - NOTE_SOURCE_FILE (tem) = 0; - -#ifdef HAVE_cc0 - /* Delete the setter too. */ - if (cc0_setter) - { - PATTERN (cc0_setter) = pc_rtx; - - distribute_notes (REG_NOTES (cc0_setter), - cc0_setter, cc0_setter, - NULL_RTX, NULL_RTX, NULL_RTX); - distribute_links (LOG_LINKS (cc0_setter)); - - PUT_CODE (cc0_setter, NOTE); - NOTE_LINE_NUMBER (cc0_setter) = NOTE_INSN_DELETED; - NOTE_SOURCE_FILE (cc0_setter) = 0; - } -#endif - } - /* If the register is both set and used here, put the - REG_DEAD note here, but place a REG_UNUSED note - here too unless there already is one. */ - else if (reg_referenced_p (XEXP (note, 0), - PATTERN (tem))) - { - place = tem; - - if (! find_regno_note (tem, REG_UNUSED, - REGNO (XEXP (note, 0)))) - REG_NOTES (tem) - = gen_rtx_EXPR_LIST (REG_UNUSED, - XEXP (note, 0), - REG_NOTES (tem)); - } - else - { - PUT_REG_NOTE_KIND (note, REG_UNUSED); - - /* If there isn't already a REG_UNUSED note, put one - here. */ - if (! find_regno_note (tem, REG_UNUSED, - REGNO (XEXP (note, 0)))) - place = tem; - break; - } - } - else if (reg_referenced_p (XEXP (note, 0), PATTERN (tem)) - || (GET_CODE (tem) == CALL_INSN - && find_reg_fusage (tem, USE, XEXP (note, 0)))) - { - place = tem; - - /* If we are doing a 3->2 combination, and we have a - register which formerly died in i3 and was not used - by i2, which now no longer dies in i3 and is used in - i2 but does not die in i2, and place is between i2 - and i3, then we may need to move a link from place to - i2. */ - if (i2 && INSN_UID (place) <= max_uid_cuid - && INSN_CUID (place) > INSN_CUID (i2) - && from_insn && INSN_CUID (from_insn) > INSN_CUID (i2) - && reg_referenced_p (XEXP (note, 0), PATTERN (i2))) - { - rtx links = LOG_LINKS (place); - LOG_LINKS (place) = 0; - distribute_links (links); - } - break; - } - } - - /* If we haven't found an insn for the death note and it - is still a REG_DEAD note, but we have hit a CODE_LABEL, - insert a USE insn for the register at that label and - put the death node there. This prevents problems with - call-state tracking in caller-save.c. */ - if (REG_NOTE_KIND (note) == REG_DEAD && place == 0 && tem != 0) - { - place - = emit_insn_after (gen_rtx_USE (VOIDmode, XEXP (note, 0)), - tem); - - /* If this insn was emitted between blocks, then update - BLOCK_HEAD of the current block to include it. */ - if (BLOCK_END (this_basic_block - 1) == tem) - BLOCK_HEAD (this_basic_block) = place; - } - } - - /* If the register is set or already dead at PLACE, we needn't do - anything with this note if it is still a REG_DEAD note. - We can here if it is set at all, not if is it totally replace, - which is what `dead_or_set_p' checks, so also check for it being - set partially. */ - - - if (place && REG_NOTE_KIND (note) == REG_DEAD) - { - int regno = REGNO (XEXP (note, 0)); - - if (dead_or_set_p (place, XEXP (note, 0)) - || reg_bitfield_target_p (XEXP (note, 0), PATTERN (place))) - { - /* Unless the register previously died in PLACE, clear - reg_last_death. [I no longer understand why this is - being done.] */ - if (reg_last_death[regno] != place) - reg_last_death[regno] = 0; - place = 0; - } - else - reg_last_death[regno] = place; - - /* If this is a death note for a hard reg that is occupying - multiple registers, ensure that we are still using all - parts of the object. If we find a piece of the object - that is unused, we must add a USE for that piece before - PLACE and put the appropriate REG_DEAD note on it. - - An alternative would be to put a REG_UNUSED for the pieces - on the insn that set the register, but that can't be done if - it is not in the same block. It is simpler, though less - efficient, to add the USE insns. */ - - if (place && regno < FIRST_PSEUDO_REGISTER - && HARD_REGNO_NREGS (regno, GET_MODE (XEXP (note, 0))) > 1) - { - int endregno - = regno + HARD_REGNO_NREGS (regno, - GET_MODE (XEXP (note, 0))); - int all_used = 1; - int i; - - for (i = regno; i < endregno; i++) - if (! refers_to_regno_p (i, i + 1, PATTERN (place), 0) - && ! find_regno_fusage (place, USE, i)) - { - rtx piece = gen_rtx_REG (reg_raw_mode[i], i); - rtx p; - - /* See if we already placed a USE note for this - register in front of PLACE. */ - for (p = place; - GET_CODE (PREV_INSN (p)) == INSN - && GET_CODE (PATTERN (PREV_INSN (p))) == USE; - p = PREV_INSN (p)) - if (rtx_equal_p (piece, - XEXP (PATTERN (PREV_INSN (p)), 0))) - { - p = 0; - break; - } - - if (p) - { - rtx use_insn - = emit_insn_before (gen_rtx_USE (VOIDmode, - piece), - p); - REG_NOTES (use_insn) - = gen_rtx_EXPR_LIST (REG_DEAD, piece, - REG_NOTES (use_insn)); - } - - all_used = 0; - } - - /* Check for the case where the register dying partially - overlaps the register set by this insn. */ - if (all_used) - for (i = regno; i < endregno; i++) - if (dead_or_set_regno_p (place, i)) - { - all_used = 0; - break; - } - - if (! all_used) - { - /* Put only REG_DEAD notes for pieces that are - still used and that are not already dead or set. */ - - for (i = regno; i < endregno; i++) - { - rtx piece = gen_rtx_REG (reg_raw_mode[i], i); - - if ((reg_referenced_p (piece, PATTERN (place)) - || (GET_CODE (place) == CALL_INSN - && find_reg_fusage (place, USE, piece))) - && ! dead_or_set_p (place, piece) - && ! reg_bitfield_target_p (piece, - PATTERN (place))) - REG_NOTES (place) - = gen_rtx_EXPR_LIST (REG_DEAD, - piece, REG_NOTES (place)); - } - - place = 0; - } - } - } - break; - - default: - /* Any other notes should not be present at this point in the - compilation. */ - abort (); - } - - if (place) - { - XEXP (note, 1) = REG_NOTES (place); - REG_NOTES (place) = note; - } - else if ((REG_NOTE_KIND (note) == REG_DEAD - || REG_NOTE_KIND (note) == REG_UNUSED) - && GET_CODE (XEXP (note, 0)) == REG) - REG_N_DEATHS (REGNO (XEXP (note, 0)))--; - - if (place2) - { - if ((REG_NOTE_KIND (note) == REG_DEAD - || REG_NOTE_KIND (note) == REG_UNUSED) - && GET_CODE (XEXP (note, 0)) == REG) - REG_N_DEATHS (REGNO (XEXP (note, 0)))++; - - REG_NOTES (place2) = gen_rtx_fmt_ee (GET_CODE (note), - REG_NOTE_KIND (note), - XEXP (note, 0), - REG_NOTES (place2)); - } - } -} - -/* Similarly to above, distribute the LOG_LINKS that used to be present on - I3, I2, and I1 to new locations. This is also called in one case to - add a link pointing at I3 when I3's destination is changed. */ - -static void -distribute_links (links) - rtx links; -{ - rtx link, next_link; - - for (link = links; link; link = next_link) - { - rtx place = 0; - rtx insn; - rtx set, reg; - - next_link = XEXP (link, 1); - - /* If the insn that this link points to is a NOTE or isn't a single - set, ignore it. In the latter case, it isn't clear what we - can do other than ignore the link, since we can't tell which - register it was for. Such links wouldn't be used by combine - anyway. - - It is not possible for the destination of the target of the link to - have been changed by combine. The only potential of this is if we - replace I3, I2, and I1 by I3 and I2. But in that case the - destination of I2 also remains unchanged. */ - - if (GET_CODE (XEXP (link, 0)) == NOTE - || (set = single_set (XEXP (link, 0))) == 0) - continue; - - reg = SET_DEST (set); - while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT - || GET_CODE (reg) == SIGN_EXTRACT - || GET_CODE (reg) == STRICT_LOW_PART) - reg = XEXP (reg, 0); - - /* A LOG_LINK is defined as being placed on the first insn that uses - a register and points to the insn that sets the register. Start - searching at the next insn after the target of the link and stop - when we reach a set of the register or the end of the basic block. - - Note that this correctly handles the link that used to point from - I3 to I2. Also note that not much searching is typically done here - since most links don't point very far away. */ - - for (insn = NEXT_INSN (XEXP (link, 0)); - (insn && (this_basic_block == n_basic_blocks - 1 - || BLOCK_HEAD (this_basic_block + 1) != insn)); - insn = NEXT_INSN (insn)) - if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' - && reg_overlap_mentioned_p (reg, PATTERN (insn))) - { - if (reg_referenced_p (reg, PATTERN (insn))) - place = insn; - break; - } - else if (GET_CODE (insn) == CALL_INSN - && find_reg_fusage (insn, USE, reg)) - { - place = insn; - break; - } - - /* If we found a place to put the link, place it there unless there - is already a link to the same insn as LINK at that point. */ - - if (place) - { - rtx link2; - - for (link2 = LOG_LINKS (place); link2; link2 = XEXP (link2, 1)) - if (XEXP (link2, 0) == XEXP (link, 0)) - break; - - if (link2 == 0) - { - XEXP (link, 1) = LOG_LINKS (place); - LOG_LINKS (place) = link; - - /* Set added_links_insn to the earliest insn we added a - link to. */ - if (added_links_insn == 0 - || INSN_CUID (added_links_insn) > INSN_CUID (place)) - added_links_insn = place; - } - } - } -} - -/* Compute INSN_CUID for INSN, which is an insn made by combine. */ - -static int -insn_cuid (insn) - rtx insn; -{ - while (insn != 0 && INSN_UID (insn) > max_uid_cuid - && GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == USE) - insn = NEXT_INSN (insn); - - if (INSN_UID (insn) > max_uid_cuid) - abort (); - - return INSN_CUID (insn); -} - -void -dump_combine_stats (file) - FILE *file; -{ - fnotice - (file, - ";; Combiner statistics: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n\n", - combine_attempts, combine_merges, combine_extras, combine_successes); -} - -void -dump_combine_total_stats (file) - FILE *file; -{ - fnotice - (file, - "\n;; Combiner totals: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n", - total_attempts, total_merges, total_extras, total_successes); -} |