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Diffstat (limited to 'gnu/usr.bin/cc/lib/fold-const.c')
| -rw-r--r-- | gnu/usr.bin/cc/lib/fold-const.c | 4479 |
1 files changed, 4479 insertions, 0 deletions
diff --git a/gnu/usr.bin/cc/lib/fold-const.c b/gnu/usr.bin/cc/lib/fold-const.c new file mode 100644 index 000000000000..6570ac2a62d5 --- /dev/null +++ b/gnu/usr.bin/cc/lib/fold-const.c @@ -0,0 +1,4479 @@ +/* Fold a constant sub-tree into a single node for C-compiler + Copyright (C) 1987, 1988, 1992, 1993 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, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/*@@ Fix lossage on folding division of big integers. */ + +/*@@ This file should be rewritten to use an arbitrary precision + @@ representation for "struct tree_int_cst" and "struct tree_real_cst". + @@ Perhaps the routines could also be used for bc/dc, and made a lib. + @@ The routines that translate from the ap rep should + @@ warn if precision et. al. is lost. + @@ This would also make life easier when this technology is used + @@ for cross-compilers. */ + + +/* The entry points in this file are fold, size_int and size_binop. + + fold takes a tree as argument and returns a simplified tree. + + size_binop takes a tree code for an arithmetic operation + and two operands that are trees, and produces a tree for the + result, assuming the type comes from `sizetype'. + + size_int takes an integer value, and creates a tree constant + with type from `sizetype'. */ + +#include <stdio.h> +#include <setjmp.h> +#include "config.h" +#include "flags.h" +#include "tree.h" + +/* Handle floating overflow for `const_binop'. */ +static jmp_buf float_error; + +void lshift_double (); +void rshift_double (); +void lrotate_double (); +void rrotate_double (); +static tree const_binop (); + +#ifndef BRANCH_COST +#define BRANCH_COST 1 +#endif + +/* Yield nonzero if a signed left shift of A by B bits overflows. */ +#define left_shift_overflows(a, b) ((a) != ((a) << (b)) >> (b)) + +/* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow. + Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1. + Then this yields nonzero if overflow occurred during the addition. + Overflow occurs if A and B have the same sign, but A and SUM differ in sign. + Use `^' to test whether signs differ, and `< 0' to isolate the sign. */ +#define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0) + +/* To do constant folding on INTEGER_CST nodes requires two-word arithmetic. + We do that by representing the two-word integer as MAX_SHORTS shorts, + with only 8 bits stored in each short, as a positive number. */ + +/* Unpack a two-word integer into MAX_SHORTS shorts. + LOW and HI are the integer, as two `HOST_WIDE_INT' pieces. + SHORTS points to the array of shorts. */ + +static void +encode (shorts, low, hi) + short *shorts; + HOST_WIDE_INT low, hi; +{ + register int i; + + for (i = 0; i < MAX_SHORTS / 2; i++) + { + shorts[i] = (low >> (i * 8)) & 0xff; + shorts[i + MAX_SHORTS / 2] = (hi >> (i * 8) & 0xff); + } +} + +/* Pack an array of MAX_SHORTS shorts into a two-word integer. + SHORTS points to the array of shorts. + The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */ + +static void +decode (shorts, low, hi) + short *shorts; + HOST_WIDE_INT *low, *hi; +{ + register int i; + HOST_WIDE_INT lv = 0, hv = 0; + + for (i = 0; i < MAX_SHORTS / 2; i++) + { + lv |= (HOST_WIDE_INT) shorts[i] << (i * 8); + hv |= (HOST_WIDE_INT) shorts[i + MAX_SHORTS / 2] << (i * 8); + } + + *low = lv, *hi = hv; +} + +/* Make the integer constant T valid for its type + by setting to 0 or 1 all the bits in the constant + that don't belong in the type. + Yield 1 if a signed overflow occurs, 0 otherwise. + If OVERFLOW is nonzero, a signed overflow has already occurred + in calculating T, so propagate it. */ + +int +force_fit_type (t, overflow) + tree t; + int overflow; +{ + HOST_WIDE_INT low, high; + register int prec; + + if (TREE_CODE (t) != INTEGER_CST) + return overflow; + + low = TREE_INT_CST_LOW (t); + high = TREE_INT_CST_HIGH (t); + + if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE) + prec = POINTER_SIZE; + else + prec = TYPE_PRECISION (TREE_TYPE (t)); + + /* First clear all bits that are beyond the type's precision. */ + + if (prec == 2 * HOST_BITS_PER_WIDE_INT) + ; + else if (prec > HOST_BITS_PER_WIDE_INT) + { + TREE_INT_CST_HIGH (t) + &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT)); + } + else + { + TREE_INT_CST_HIGH (t) = 0; + if (prec < HOST_BITS_PER_WIDE_INT) + TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec); + } + + /* Unsigned types do not suffer sign extension or overflow. */ + if (TREE_UNSIGNED (TREE_TYPE (t))) + return 0; + + /* If the value's sign bit is set, extend the sign. */ + if (prec != 2 * HOST_BITS_PER_WIDE_INT + && (prec > HOST_BITS_PER_WIDE_INT + ? (TREE_INT_CST_HIGH (t) + & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1))) + : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1)))) + { + /* Value is negative: + set to 1 all the bits that are outside this type's precision. */ + if (prec > HOST_BITS_PER_WIDE_INT) + { + TREE_INT_CST_HIGH (t) + |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT)); + } + else + { + TREE_INT_CST_HIGH (t) = -1; + if (prec < HOST_BITS_PER_WIDE_INT) + TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec); + } + } + + /* Yield nonzero if signed overflow occurred. */ + return + ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t))) + != 0); +} + +/* Add two doubleword integers with doubleword result. + Each argument is given as two `HOST_WIDE_INT' pieces. + One argument is L1 and H1; the other, L2 and H2. + The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. + We use the 8-shorts representation internally. */ + +int +add_double (l1, h1, l2, h2, lv, hv) + HOST_WIDE_INT l1, h1, l2, h2; + HOST_WIDE_INT *lv, *hv; +{ + short arg1[MAX_SHORTS]; + short arg2[MAX_SHORTS]; + register int carry = 0; + register int i; + + encode (arg1, l1, h1); + encode (arg2, l2, h2); + + for (i = 0; i < MAX_SHORTS; i++) + { + carry += arg1[i] + arg2[i]; + arg1[i] = carry & 0xff; + carry >>= 8; + } + + decode (arg1, lv, hv); + return overflow_sum_sign (h1, h2, *hv); +} + +/* Negate a doubleword integer with doubleword result. + Return nonzero if the operation overflows, assuming it's signed. + The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1. + The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. + We use the 8-shorts representation internally. */ + +int +neg_double (l1, h1, lv, hv) + HOST_WIDE_INT l1, h1; + HOST_WIDE_INT *lv, *hv; +{ + if (l1 == 0) + { + *lv = 0; + *hv = - h1; + return (*hv & h1) < 0; + } + else + { + *lv = - l1; + *hv = ~ h1; + return 0; + } +} + +/* Multiply two doubleword integers with doubleword result. + Return nonzero if the operation overflows, assuming it's signed. + Each argument is given as two `HOST_WIDE_INT' pieces. + One argument is L1 and H1; the other, L2 and H2. + The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. + We use the 8-shorts representation internally. */ + +int +mul_double (l1, h1, l2, h2, lv, hv) + HOST_WIDE_INT l1, h1, l2, h2; + HOST_WIDE_INT *lv, *hv; +{ + short arg1[MAX_SHORTS]; + short arg2[MAX_SHORTS]; + short prod[MAX_SHORTS * 2]; + register int carry = 0; + register int i, j, k; + HOST_WIDE_INT toplow, tophigh, neglow, neghigh; + + /* These cases are used extensively, arising from pointer combinations. */ + if (h2 == 0) + { + if (l2 == 2) + { + int overflow = left_shift_overflows (h1, 1); + unsigned HOST_WIDE_INT temp = l1 + l1; + *hv = (h1 << 1) + (temp < l1); + *lv = temp; + return overflow; + } + if (l2 == 4) + { + int overflow = left_shift_overflows (h1, 2); + unsigned HOST_WIDE_INT temp = l1 + l1; + h1 = (h1 << 2) + ((temp < l1) << 1); + l1 = temp; + temp += temp; + h1 += (temp < l1); + *lv = temp; + *hv = h1; + return overflow; + } + if (l2 == 8) + { + int overflow = left_shift_overflows (h1, 3); + unsigned HOST_WIDE_INT temp = l1 + l1; + h1 = (h1 << 3) + ((temp < l1) << 2); + l1 = temp; + temp += temp; + h1 += (temp < l1) << 1; + l1 = temp; + temp += temp; + h1 += (temp < l1); + *lv = temp; + *hv = h1; + return overflow; + } + } + + encode (arg1, l1, h1); + encode (arg2, l2, h2); + + bzero (prod, sizeof prod); + + for (i = 0; i < MAX_SHORTS; i++) + for (j = 0; j < MAX_SHORTS; j++) + { + k = i + j; + carry = arg1[i] * arg2[j]; + while (carry) + { + carry += prod[k]; + prod[k] = carry & 0xff; + carry >>= 8; + k++; + } + } + + decode (prod, lv, hv); /* This ignores + prod[MAX_SHORTS] -> prod[MAX_SHORTS*2-1] */ + + /* Check for overflow by calculating the top half of the answer in full; + it should agree with the low half's sign bit. */ + decode (prod+MAX_SHORTS, &toplow, &tophigh); + if (h1 < 0) + { + neg_double (l2, h2, &neglow, &neghigh); + add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh); + } + if (h2 < 0) + { + neg_double (l1, h1, &neglow, &neghigh); + add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh); + } + return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0; +} + +/* Shift the doubleword integer in L1, H1 left by COUNT places + keeping only PREC bits of result. + Shift right if COUNT is negative. + ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. + Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ + +void +lshift_double (l1, h1, count, prec, lv, hv, arith) + HOST_WIDE_INT l1, h1; + int count, prec; + HOST_WIDE_INT *lv, *hv; + int arith; +{ + short arg1[MAX_SHORTS]; + register int i; + register int carry; + + if (count < 0) + { + rshift_double (l1, h1, - count, prec, lv, hv, arith); + return; + } + + encode (arg1, l1, h1); + + if (count > prec) + count = prec; + + while (count > 0) + { + carry = 0; + for (i = 0; i < MAX_SHORTS; i++) + { + carry += arg1[i] << 1; + arg1[i] = carry & 0xff; + carry >>= 8; + } + count--; + } + + decode (arg1, lv, hv); +} + +/* Shift the doubleword integer in L1, H1 right by COUNT places + keeping only PREC bits of result. COUNT must be positive. + ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. + Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ + +void +rshift_double (l1, h1, count, prec, lv, hv, arith) + HOST_WIDE_INT l1, h1, count, prec; + HOST_WIDE_INT *lv, *hv; + int arith; +{ + short arg1[MAX_SHORTS]; + register int i; + register int carry; + + encode (arg1, l1, h1); + + if (count > prec) + count = prec; + + while (count > 0) + { + carry = arith && arg1[7] >> 7; + for (i = MAX_SHORTS - 1; i >= 0; i--) + { + carry <<= 8; + carry += arg1[i]; + arg1[i] = (carry >> 1) & 0xff; + } + count--; + } + + decode (arg1, lv, hv); +} + +/* Rotate the doubldword integer in L1, H1 left by COUNT places + keeping only PREC bits of result. + Rotate right if COUNT is negative. + Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ + +void +lrotate_double (l1, h1, count, prec, lv, hv) + HOST_WIDE_INT l1, h1, count, prec; + HOST_WIDE_INT *lv, *hv; +{ + short arg1[MAX_SHORTS]; + register int i; + register int carry; + + if (count < 0) + { + rrotate_double (l1, h1, - count, prec, lv, hv); + return; + } + + encode (arg1, l1, h1); + + if (count > prec) + count = prec; + + carry = arg1[MAX_SHORTS - 1] >> 7; + while (count > 0) + { + for (i = 0; i < MAX_SHORTS; i++) + { + carry += arg1[i] << 1; + arg1[i] = carry & 0xff; + carry >>= 8; + } + count--; + } + + decode (arg1, lv, hv); +} + +/* Rotate the doubleword integer in L1, H1 left by COUNT places + keeping only PREC bits of result. COUNT must be positive. + Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ + +void +rrotate_double (l1, h1, count, prec, lv, hv) + HOST_WIDE_INT l1, h1, count, prec; + HOST_WIDE_INT *lv, *hv; +{ + short arg1[MAX_SHORTS]; + register int i; + register int carry; + + encode (arg1, l1, h1); + + if (count > prec) + count = prec; + + carry = arg1[0] & 1; + while (count > 0) + { + for (i = MAX_SHORTS - 1; i >= 0; i--) + { + carry <<= 8; + carry += arg1[i]; + arg1[i] = (carry >> 1) & 0xff; + } + count--; + } + + decode (arg1, lv, hv); +} + +/* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN + for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM). + CODE is a tree code for a kind of division, one of + TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR + or EXACT_DIV_EXPR + It controls how the quotient is rounded to a integer. + Return nonzero if the operation overflows. + UNS nonzero says do unsigned division. */ + +static int +div_and_round_double (code, uns, + lnum_orig, hnum_orig, lden_orig, hden_orig, + lquo, hquo, lrem, hrem) + enum tree_code code; + int uns; + HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */ + HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */ + HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem; +{ + int quo_neg = 0; + short num[MAX_SHORTS + 1]; /* extra element for scaling. */ + short den[MAX_SHORTS], quo[MAX_SHORTS]; + register int i, j, work; + register int carry = 0; + HOST_WIDE_INT lnum = lnum_orig; + HOST_WIDE_INT hnum = hnum_orig; + HOST_WIDE_INT lden = lden_orig; + HOST_WIDE_INT hden = hden_orig; + int overflow = 0; + + if ((hden == 0) && (lden == 0)) + abort (); + + /* calculate quotient sign and convert operands to unsigned. */ + if (!uns) + { + if (hnum < 0) + { + quo_neg = ~ quo_neg; + /* (minimum integer) / (-1) is the only overflow case. */ + if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1) + overflow = 1; + } + if (hden < 0) + { + quo_neg = ~ quo_neg; + neg_double (lden, hden, &lden, &hden); + } + } + + if (hnum == 0 && hden == 0) + { /* single precision */ + *hquo = *hrem = 0; + /* This unsigned division rounds toward zero. */ + *lquo = lnum / (unsigned HOST_WIDE_INT) lden; + goto finish_up; + } + + if (hnum == 0) + { /* trivial case: dividend < divisor */ + /* hden != 0 already checked. */ + *hquo = *lquo = 0; + *hrem = hnum; + *lrem = lnum; + goto finish_up; + } + + bzero (quo, sizeof quo); + + bzero (num, sizeof num); /* to zero 9th element */ + bzero (den, sizeof den); + + encode (num, lnum, hnum); + encode (den, lden, hden); + + /* This code requires more than just hden == 0. + We also have to require that we don't need more than three bytes + to hold CARRY. If we ever did need four bytes to hold it, we + would lose part of it when computing WORK on the next round. */ + if (hden == 0 && (((unsigned HOST_WIDE_INT) lden << 8) >> 8) == lden) + { /* simpler algorithm */ + /* hnum != 0 already checked. */ + for (i = MAX_SHORTS - 1; i >= 0; i--) + { + work = num[i] + (carry << 8); + quo[i] = work / (unsigned HOST_WIDE_INT) lden; + carry = work % (unsigned HOST_WIDE_INT) lden; + } + } + else { /* full double precision, + with thanks to Don Knuth's + "Seminumerical Algorithms". */ +#define BASE 256 + int quo_est, scale, num_hi_sig, den_hi_sig, quo_hi_sig; + + /* Find the highest non-zero divisor digit. */ + for (i = MAX_SHORTS - 1; ; i--) + if (den[i] != 0) { + den_hi_sig = i; + break; + } + for (i = MAX_SHORTS - 1; ; i--) + if (num[i] != 0) { + num_hi_sig = i; + break; + } + quo_hi_sig = num_hi_sig - den_hi_sig + 1; + + /* Insure that the first digit of the divisor is at least BASE/2. + This is required by the quotient digit estimation algorithm. */ + + scale = BASE / (den[den_hi_sig] + 1); + if (scale > 1) { /* scale divisor and dividend */ + carry = 0; + for (i = 0; i <= MAX_SHORTS - 1; i++) { + work = (num[i] * scale) + carry; + num[i] = work & 0xff; + carry = work >> 8; + if (num[i] != 0) num_hi_sig = i; + } + carry = 0; + for (i = 0; i <= MAX_SHORTS - 1; i++) { + work = (den[i] * scale) + carry; + den[i] = work & 0xff; + carry = work >> 8; + if (den[i] != 0) den_hi_sig = i; + } + } + + /* Main loop */ + for (i = quo_hi_sig; i > 0; i--) { + /* guess the next quotient digit, quo_est, by dividing the first + two remaining dividend digits by the high order quotient digit. + quo_est is never low and is at most 2 high. */ + + int num_hi; /* index of highest remaining dividend digit */ + + num_hi = i + den_hi_sig; + + work = (num[num_hi] * BASE) + (num_hi > 0 ? num[num_hi - 1] : 0); + if (num[num_hi] != den[den_hi_sig]) { + quo_est = work / den[den_hi_sig]; + } + else { + quo_est = BASE - 1; + } + + /* refine quo_est so it's usually correct, and at most one high. */ + while ((den[den_hi_sig - 1] * quo_est) + > (((work - (quo_est * den[den_hi_sig])) * BASE) + + ((num_hi - 1) > 0 ? num[num_hi - 2] : 0))) + quo_est--; + + /* Try QUO_EST as the quotient digit, by multiplying the + divisor by QUO_EST and subtracting from the remaining dividend. + Keep in mind that QUO_EST is the I - 1st digit. */ + + carry = 0; + + for (j = 0; j <= den_hi_sig; j++) + { + int digit; + + work = num[i + j - 1] - (quo_est * den[j]) + carry; + digit = work & 0xff; + carry = work >> 8; + if (digit < 0) + { + digit += BASE; + carry--; + } + num[i + j - 1] = digit; + } + + /* if quo_est was high by one, then num[i] went negative and + we need to correct things. */ + + if (num[num_hi] < 0) + { + quo_est--; + carry = 0; /* add divisor back in */ + for (j = 0; j <= den_hi_sig; j++) + { + work = num[i + j - 1] + den[j] + carry; + if (work > BASE) + { + work -= BASE; + carry = 1; + } + else + { + carry = 0; + } + num[i + j - 1] = work; + } + num [num_hi] += carry; + } + + /* store the quotient digit. */ + quo[i - 1] = quo_est; + } + } + + decode (quo, lquo, hquo); + + finish_up: + /* if result is negative, make it so. */ + if (quo_neg) + neg_double (*lquo, *hquo, lquo, hquo); + + /* compute trial remainder: rem = num - (quo * den) */ + mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); + neg_double (*lrem, *hrem, lrem, hrem); + add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); + + switch (code) + { + case TRUNC_DIV_EXPR: + case TRUNC_MOD_EXPR: /* round toward zero */ + case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */ + return overflow; + + case FLOOR_DIV_EXPR: + case FLOOR_MOD_EXPR: /* round toward negative infinity */ + if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */ + { + /* quo = quo - 1; */ + add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, + lquo, hquo); + } + else return overflow; + break; + + case CEIL_DIV_EXPR: + case CEIL_MOD_EXPR: /* round toward positive infinity */ + if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */ + { + add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0, + lquo, hquo); + } + else return overflow; + break; + + case ROUND_DIV_EXPR: + case ROUND_MOD_EXPR: /* round to closest integer */ + { + HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem; + HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice; + + /* get absolute values */ + if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem); + if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den); + + /* if (2 * abs (lrem) >= abs (lden)) */ + mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0, + labs_rem, habs_rem, <wice, &htwice); + if (((unsigned HOST_WIDE_INT) habs_den + < (unsigned HOST_WIDE_INT) htwice) + || (((unsigned HOST_WIDE_INT) habs_den + == (unsigned HOST_WIDE_INT) htwice) + && ((HOST_WIDE_INT unsigned) labs_den + < (unsigned HOST_WIDE_INT) ltwice))) + { + if (*hquo < 0) + /* quo = quo - 1; */ + add_double (*lquo, *hquo, + (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo); + else + /* quo = quo + 1; */ + add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0, + lquo, hquo); + } + else return overflow; + } + break; + + default: + abort (); + } + + /* compute true remainder: rem = num - (quo * den) */ + mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); + neg_double (*lrem, *hrem, lrem, hrem); + add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); + return overflow; +} + +#ifndef REAL_ARITHMETIC +/* Effectively truncate a real value to represent + the nearest possible value in a narrower mode. + The result is actually represented in the same data type as the argument, + but its value is usually different. */ + +REAL_VALUE_TYPE +real_value_truncate (mode, arg) + enum machine_mode mode; + REAL_VALUE_TYPE arg; +{ +#ifdef __STDC__ + /* Make sure the value is actually stored in memory before we turn off + the handler. */ + volatile +#endif + REAL_VALUE_TYPE value; + jmp_buf handler, old_handler; + int handled; + + if (setjmp (handler)) + { + error ("floating overflow"); + return dconst0; + } + handled = push_float_handler (handler, old_handler); + value = REAL_VALUE_TRUNCATE (mode, arg); + pop_float_handler (handled, old_handler); + return value; +} + +#if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT + +/* Check for infinity in an IEEE double precision number. */ + +int +target_isinf (x) + REAL_VALUE_TYPE x; +{ + /* The IEEE 64-bit double format. */ + union { + REAL_VALUE_TYPE d; + struct { + unsigned sign : 1; + unsigned exponent : 11; + unsigned mantissa1 : 20; + unsigned mantissa2; + } little_endian; + struct { + unsigned mantissa2; + unsigned mantissa1 : 20; + unsigned exponent : 11; + unsigned sign : 1; + } big_endian; + } u; + + u.d = dconstm1; + if (u.big_endian.sign == 1) + { + u.d = x; + return (u.big_endian.exponent == 2047 + && u.big_endian.mantissa1 == 0 + && u.big_endian.mantissa2 == 0); + } + else + { + u.d = x; + return (u.little_endian.exponent == 2047 + && u.little_endian.mantissa1 == 0 + && u.little_endian.mantissa2 == 0); + } +} + +/* Check whether an IEEE double precision number is a NaN. */ + +int +target_isnan (x) + REAL_VALUE_TYPE x; +{ + /* The IEEE 64-bit double format. */ + union { + REAL_VALUE_TYPE d; + struct { + unsigned sign : 1; + unsigned exponent : 11; + unsigned mantissa1 : 20; + unsigned mantissa2; + } little_endian; + struct { + unsigned mantissa2; + unsigned mantissa1 : 20; + unsigned exponent : 11; + unsigned sign : 1; + } big_endian; + } u; + + u.d = dconstm1; + if (u.big_endian.sign == 1) + { + u.d = x; + return (u.big_endian.exponent == 2047 + && (u.big_endian.mantissa1 != 0 + || u.big_endian.mantissa2 != 0)); + } + else + { + u.d = x; + return (u.little_endian.exponent == 2047 + && (u.little_endian.mantissa1 != 0 + || u.little_endian.mantissa2 != 0)); + } +} + +/* Check for a negative IEEE double precision number. */ + +int +target_negative (x) + REAL_VALUE_TYPE x; +{ + /* The IEEE 64-bit double format. */ + union { + REAL_VALUE_TYPE d; + struct { + unsigned sign : 1; + unsigned exponent : 11; + unsigned mantissa1 : 20; + unsigned mantissa2; + } little_endian; + struct { + unsigned mantissa2; + unsigned mantissa1 : 20; + unsigned exponent : 11; + unsigned sign : 1; + } big_endian; + } u; + + u.d = dconstm1; + if (u.big_endian.sign == 1) + { + u.d = x; + return u.big_endian.sign; + } + else + { + u.d = x; + return u.little_endian.sign; + } +} +#else /* Target not IEEE */ + +/* Let's assume other float formats don't have infinity. + (This can be overridden by redefining REAL_VALUE_ISINF.) */ + +target_isinf (x) + REAL_VALUE_TYPE x; +{ + return 0; +} + +/* Let's assume other float formats don't have NaNs. + (This can be overridden by redefining REAL_VALUE_ISNAN.) */ + +target_isnan (x) + REAL_VALUE_TYPE x; +{ + return 0; +} + +/* Let's assume other float formats don't have minus zero. + (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */ + +target_negative (x) + REAL_VALUE_TYPE x; +{ + return x < 0; +} +#endif /* Target not IEEE */ +#endif /* no REAL_ARITHMETIC */ + +/* Split a tree IN into a constant and a variable part + that could be combined with CODE to make IN. + CODE must be a commutative arithmetic operation. + Store the constant part into *CONP and the variable in &VARP. + Return 1 if this was done; zero means the tree IN did not decompose + this way. + + If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. + Therefore, we must tell the caller whether the variable part + was subtracted. We do this by storing 1 or -1 into *VARSIGNP. + The value stored is the coefficient for the variable term. + The constant term we return should always be added; + we negate it if necessary. */ + +static int +split_tree (in, code, varp, conp, varsignp) + tree in; + enum tree_code code; + tree *varp, *conp; + int *varsignp; +{ + register tree outtype = TREE_TYPE (in); + *varp = 0; + *conp = 0; + + /* Strip any conversions that don't change the machine mode. */ + while ((TREE_CODE (in) == NOP_EXPR + || TREE_CODE (in) == CONVERT_EXPR) + && (TYPE_MODE (TREE_TYPE (in)) + == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0))))) + in = TREE_OPERAND (in, 0); + + if (TREE_CODE (in) == code + || (! FLOAT_TYPE_P (TREE_TYPE (in)) + /* We can associate addition and subtraction together + (even though the C standard doesn't say so) + for integers because the value is not affected. + For reals, the value might be affected, so we can't. */ + && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR) + || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR)))) + { + enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0)); + if (code == INTEGER_CST) + { + *conp = TREE_OPERAND (in, 0); + *varp = TREE_OPERAND (in, 1); + if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) + && TREE_TYPE (*varp) != outtype) + *varp = convert (outtype, *varp); + *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1; + return 1; + } + if (TREE_CONSTANT (TREE_OPERAND (in, 1))) + { + *conp = TREE_OPERAND (in, 1); + *varp = TREE_OPERAND (in, 0); + *varsignp = 1; + if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) + && TREE_TYPE (*varp) != outtype) + *varp = convert (outtype, *varp); + if (TREE_CODE (in) == MINUS_EXPR) + { + /* If operation is subtraction and constant is second, + must negate it to get an additive constant. + And this cannot be done unless it is a manifest constant. + It could also be the address of a static variable. + We cannot negate that, so give up. */ + if (TREE_CODE (*conp) == INTEGER_CST) + /* Subtracting from integer_zero_node loses for long long. */ + *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp)); + else + return 0; + } + return 1; + } + if (TREE_CONSTANT (TREE_OPERAND (in, 0))) + { + *conp = TREE_OPERAND (in, 0); + *varp = TREE_OPERAND (in, 1); + if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) + && TREE_TYPE (*varp) != outtype) + *varp = convert (outtype, *varp); + *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1; + return 1; + } + } + return 0; +} + +/* Combine two constants NUM and ARG2 under operation CODE + to produce a new constant. + We assume ARG1 and ARG2 have the same data type, + or at least are the same kind of constant and the same machine mode. + + If NOTRUNC is nonzero, do not truncate the result to fit the data type. */ + +static tree +const_binop (code, arg1, arg2, notrunc) + enum tree_code code; + register tree arg1, arg2; + int notrunc; +{ + if (TREE_CODE (arg1) == INTEGER_CST) + { + register HOST_WIDE_INT int1l = TREE_INT_CST_LOW (arg1); + register HOST_WIDE_INT int1h = TREE_INT_CST_HIGH (arg1); + HOST_WIDE_INT int2l = TREE_INT_CST_LOW (arg2); + HOST_WIDE_INT int2h = TREE_INT_CST_HIGH (arg2); + HOST_WIDE_INT low, hi; + HOST_WIDE_INT garbagel, garbageh; + register tree t; + int uns = TREE_UNSIGNED (TREE_TYPE (arg1)); + int overflow = 0; + + switch (code) + { + case BIT_IOR_EXPR: + t = build_int_2 (int1l | int2l, int1h | int2h); + break; + + case BIT_XOR_EXPR: + t = build_int_2 (int1l ^ int2l, int1h ^ int2h); + break; + + case BIT_AND_EXPR: + t = build_int_2 (int1l & int2l, int1h & int2h); + break; + + case BIT_ANDTC_EXPR: + t = build_int_2 (int1l & ~int2l, int1h & ~int2h); + break; + + case RSHIFT_EXPR: + int2l = - int2l; + case LSHIFT_EXPR: + /* It's unclear from the C standard whether shifts can overflow. + The following code ignores overflow; perhaps a C standard + interpretation ruling is needed. */ + lshift_double (int1l, int1h, int2l, + TYPE_PRECISION (TREE_TYPE (arg1)), + &low, &hi, + !uns); + t = build_int_2 (low, hi); + TREE_TYPE (t) = TREE_TYPE (arg1); + if (!notrunc) + force_fit_type (t, 0); + TREE_CONSTANT_OVERFLOW (t) + = TREE_CONSTANT_OVERFLOW (arg1) | TREE_CONSTANT_OVERFLOW (arg2); + return t; + + case RROTATE_EXPR: + int2l = - int2l; + case LROTATE_EXPR: + lrotate_double (int1l, int1h, int2l, + TYPE_PRECISION (TREE_TYPE (arg1)), + &low, &hi); + t = build_int_2 (low, hi); + break; + + case PLUS_EXPR: + if (int1h == 0) + { + int2l += int1l; + if ((unsigned HOST_WIDE_INT) int2l < int1l) + { + hi = int2h++; + overflow = int2h < hi; + } + t = build_int_2 (int2l, int2h); + break; + } + if (int2h == 0) + { + int1l += int2l; + if ((unsigned HOST_WIDE_INT) int1l < int2l) + { + hi = int1h++; + overflow = int1h < hi; + } + t = build_int_2 (int1l, int1h); + break; + } + overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi); + t = build_int_2 (low, hi); + break; + + case MINUS_EXPR: + if (int2h == 0 && int2l == 0) + { + t = build_int_2 (int1l, int1h); + break; + } + neg_double (int2l, int2h, &low, &hi); + add_double (int1l, int1h, low, hi, &low, &hi); + overflow = overflow_sum_sign (hi, int2h, int1h); + t = build_int_2 (low, hi); + break; + + case MULT_EXPR: + /* Optimize simple cases. */ + if (int1h == 0) + { + unsigned HOST_WIDE_INT temp; + + switch (int1l) + { + case 0: + t = build_int_2 (0, 0); + goto got_it; + case 1: + t = build_int_2 (int2l, int2h); + goto got_it; + case 2: + overflow = left_shift_overflows (int2h, 1); + temp = int2l + int2l; + int2h = (int2h << 1) + (temp < int2l); + t = build_int_2 (temp, int2h); + goto got_it; +#if 0 /* This code can lose carries. */ + case 3: + temp = int2l + int2l + int2l; + int2h = int2h * 3 + (temp < int2l); + t = build_int_2 (temp, int2h); + goto got_it; +#endif + case 4: + overflow = left_shift_overflows (int2h, 2); + temp = int2l + int2l; + int2h = (int2h << 2) + ((temp < int2l) << 1); + int2l = temp; + temp += temp; + int2h += (temp < int2l); + t = build_int_2 (temp, int2h); + goto got_it; + case 8: + overflow = left_shift_overflows (int2h, 3); + temp = int2l + int2l; + int2h = (int2h << 3) + ((temp < int2l) << 2); + int2l = temp; + temp += temp; + int2h += (temp < int2l) << 1; + int2l = temp; + temp += temp; + int2h += (temp < int2l); + t = build_int_2 (temp, int2h); + goto got_it; + default: + break; + } + } + + if (int2h == 0) + { + if (int2l == 0) + { + t = build_int_2 (0, 0); + break; + } + if (int2l == 1) + { + t = build_int_2 (int1l, int1h); + break; + } + } + + overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi); + t = build_int_2 (low, hi); + break; + + case TRUNC_DIV_EXPR: + case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR: + case EXACT_DIV_EXPR: + /* This is a shortcut for a common special case. + It reduces the number of tree nodes generated + and saves time. */ + if (int2h == 0 && int2l > 0 + && TREE_TYPE (arg1) == sizetype + && int1h == 0 && int1l >= 0) + { + if (code == CEIL_DIV_EXPR) + int1l += int2l-1; + return size_int (int1l / int2l); + } + case ROUND_DIV_EXPR: + if (int2h == 0 && int2l == 1) + { + t = build_int_2 (int1l, int1h); + break; + } + if (int1l == int2l && int1h == int2h) + { + if ((int1l | int1h) == 0) + abort (); + t = build_int_2 (1, 0); + break; + } + overflow = div_and_round_double (code, uns, + int1l, int1h, int2l, int2h, + &low, &hi, &garbagel, &garbageh); + t = build_int_2 (low, hi); + break; + + case TRUNC_MOD_EXPR: case ROUND_MOD_EXPR: + case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR: + overflow = div_and_round_double (code, uns, + int1l, int1h, int2l, int2h, + &garbagel, &garbageh, &low, &hi); + t = build_int_2 (low, hi); + break; + + case MIN_EXPR: + case MAX_EXPR: + if (uns) + { + low = (((unsigned HOST_WIDE_INT) int1h + < (unsigned HOST_WIDE_INT) int2h) + || (((unsigned HOST_WIDE_INT) int1h + == (unsigned HOST_WIDE_INT) int2h) + && ((unsigned HOST_WIDE_INT) int1l + < (unsigned HOST_WIDE_INT) int2l))); + } + else + { + low = ((int1h < int2h) + || ((int1h == int2h) + && ((unsigned HOST_WIDE_INT) int1l + < (unsigned HOST_WIDE_INT) int2l))); + } + if (low == (code == MIN_EXPR)) + t = build_int_2 (int1l, int1h); + else + t = build_int_2 (int2l, int2h); + break; + + default: + abort (); + } + got_it: + TREE_TYPE (t) = TREE_TYPE (arg1); + TREE_CONSTANT_OVERFLOW (t) + = ((notrunc ? !uns && overflow : force_fit_type (t, overflow)) + | TREE_CONSTANT_OVERFLOW (arg1) + | TREE_CONSTANT_OVERFLOW (arg2)); + return t; + } +#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) + if (TREE_CODE (arg1) == REAL_CST) + { + REAL_VALUE_TYPE d1; + REAL_VALUE_TYPE d2; + REAL_VALUE_TYPE value; + tree t; + + d1 = TREE_REAL_CST (arg1); + d2 = TREE_REAL_CST (arg2); + if (setjmp (float_error)) + { + pedwarn ("floating overflow in constant expression"); + return build (code, TREE_TYPE (arg1), arg1, arg2); + } + set_float_handler (float_error); + +#ifdef REAL_ARITHMETIC + REAL_ARITHMETIC (value, code, d1, d2); +#else + switch (code) + { + case PLUS_EXPR: + value = d1 + d2; + break; + + case MINUS_EXPR: + value = d1 - d2; + break; + + case MULT_EXPR: + value = d1 * d2; + break; + + case RDIV_EXPR: +#ifndef REAL_INFINITY + if (d2 == 0) + abort (); +#endif + + value = d1 / d2; + break; + + case MIN_EXPR: + value = MIN (d1, d2); + break; + + case MAX_EXPR: + value = MAX (d1, d2); + break; + + default: + abort (); + } +#endif /* no REAL_ARITHMETIC */ + t = build_real (TREE_TYPE (arg1), + real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value)); + set_float_handler (NULL_PTR); + return t; + } +#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ + if (TREE_CODE (arg1) == COMPLEX_CST) + { + register tree r1 = TREE_REALPART (arg1); + register tree i1 = TREE_IMAGPART (arg1); + register tree r2 = TREE_REALPART (arg2); + register tree i2 = TREE_IMAGPART (arg2); + register tree t; + + switch (code) + { + case PLUS_EXPR: + t = build_complex (const_binop (PLUS_EXPR, r1, r2, notrunc), + const_binop (PLUS_EXPR, i1, i2, notrunc)); + break; + + case MINUS_EXPR: + t = build_complex (const_binop (MINUS_EXPR, r1, r2, notrunc), + const_binop (MINUS_EXPR, i1, i2, notrunc)); + break; + + case MULT_EXPR: + t = build_complex (const_binop (MINUS_EXPR, + const_binop (MULT_EXPR, + r1, r2, notrunc), + const_binop (MULT_EXPR, + i1, i2, notrunc), + notrunc), + const_binop (PLUS_EXPR, + const_binop (MULT_EXPR, + r1, i2, notrunc), + const_binop (MULT_EXPR, + i1, r2, notrunc), + notrunc)); + break; + + case RDIV_EXPR: + { + register tree magsquared + = const_binop (PLUS_EXPR, + const_binop (MULT_EXPR, r2, r2, notrunc), + const_binop (MULT_EXPR, i2, i2, notrunc), + notrunc); + t = build_complex (const_binop (RDIV_EXPR, + const_binop (PLUS_EXPR, + const_binop (MULT_EXPR, r1, r2, notrunc), + const_binop (MULT_EXPR, i1, i2, notrunc), + notrunc), + magsquared, notrunc), + const_binop (RDIV_EXPR, + const_binop (MINUS_EXPR, + const_binop (MULT_EXPR, i1, r2, notrunc), + const_binop (MULT_EXPR, r1, i2, notrunc), + notrunc), + magsquared, notrunc)); + } + break; + + default: + abort (); + } + TREE_TYPE (t) = TREE_TYPE (arg1); + return t; + } + return 0; +} + +/* Return an INTEGER_CST with value V and type from `sizetype'. */ + +tree +size_int (number) + unsigned int number; +{ + register tree t; + /* Type-size nodes already made for small sizes. */ + static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1]; + + if (number < 2*HOST_BITS_PER_WIDE_INT + 1 + && size_table[number] != 0) + return size_table[number]; + if (number < 2*HOST_BITS_PER_WIDE_INT + 1) + { + push_obstacks_nochange (); + /* Make this a permanent node. */ + end_temporary_allocation (); + t = build_int_2 (number, 0); + TREE_TYPE (t) = sizetype; + size_table[number] = t; + pop_obstacks (); + } + else + { + t = build_int_2 (number, 0); + TREE_TYPE (t) = sizetype; + } + return t; +} + +/* Combine operands OP1 and OP2 with arithmetic operation CODE. + CODE is a tree code. Data type is taken from `sizetype', + If the operands are constant, so is the result. */ + +tree +size_binop (code, arg0, arg1) + enum tree_code code; + tree arg0, arg1; +{ + /* Handle the special case of two integer constants faster. */ + if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) + { + /* And some specific cases even faster than that. */ + if (code == PLUS_EXPR + && TREE_INT_CST_LOW (arg0) == 0 + && TREE_INT_CST_HIGH (arg0) == 0) + return arg1; + if (code == MINUS_EXPR + && TREE_INT_CST_LOW (arg1) == 0 + && TREE_INT_CST_HIGH (arg1) == 0) + return arg0; + if (code == MULT_EXPR + && TREE_INT_CST_LOW (arg0) == 1 + && TREE_INT_CST_HIGH (arg0) == 0) + return arg1; + /* Handle general case of two integer constants. */ + return const_binop (code, arg0, arg1, 1); + } + + if (arg0 == error_mark_node || arg1 == error_mark_node) + return error_mark_node; + + return fold (build (code, sizetype, arg0, arg1)); +} + +/* Given T, a tree representing type conversion of ARG1, a constant, + return a constant tree representing the result of conversion. */ + +static tree +fold_convert (t, arg1) + register tree t; + register tree arg1; +{ + register tree type = TREE_TYPE (t); + + if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type)) + { + if (TREE_CODE (arg1) == INTEGER_CST) + { + /* Given an integer constant, make new constant with new type, + appropriately sign-extended or truncated. */ + t = build_int_2 (TREE_INT_CST_LOW (arg1), + TREE_INT_CST_HIGH (arg1)); + TREE_TYPE (t) = type; + /* Indicate an overflow if (1) ARG1 already overflowed, + or (2) ARG1 is a too-large unsigned value and T is signed, + or (3) force_fit_type indicates an overflow. + force_fit_type can't detect (2), since it sees only T's type. */ + TREE_CONSTANT_OVERFLOW (t) = + (TREE_CONSTANT_OVERFLOW (arg1) + | (TREE_INT_CST_HIGH (arg1) < 0 + & TREE_UNSIGNED (type) < TREE_UNSIGNED (TREE_TYPE (arg1))) + | force_fit_type (t, 0)); + } +#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) + else if (TREE_CODE (arg1) == REAL_CST) + { + REAL_VALUE_TYPE l, x, u; + + l = real_value_from_int_cst (TYPE_MIN_VALUE (type)); + x = TREE_REAL_CST (arg1); + u = real_value_from_int_cst (TYPE_MAX_VALUE (type)); + + /* See if X will be in range after truncation towards 0. + To compensate for truncation, move the bounds away from 0, + but reject if X exactly equals the adjusted bounds. */ +#ifdef REAL_ARITHMETIC + REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1); + REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1); +#else + l--; + u++; +#endif + if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u))) + { + pedwarn ("real constant out of range for integer conversion"); + return t; + } +#ifndef REAL_ARITHMETIC + { + REAL_VALUE_TYPE d; + HOST_WIDE_INT low, high; + HOST_WIDE_INT half_word + = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2); + + d = TREE_REAL_CST (arg1); + if (d < 0) + d = -d; + + high = (HOST_WIDE_INT) (d / half_word / half_word); + d -= (REAL_VALUE_TYPE) high * half_word * half_word; + if (d >= (REAL_VALUE_TYPE) half_word * half_word / 2) + { + low = d - (REAL_VALUE_TYPE) half_word * half_word / 2; + low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1); + } + else + low = (HOST_WIDE_INT) d; + if (TREE_REAL_CST (arg1) < 0) + neg_double (low, high, &low, &high); + t = build_int_2 (low, high); + } +#else + { + HOST_WIDE_INT low, high; + REAL_VALUE_TO_INT (&low, &high, (TREE_REAL_CST (arg1))); + t = build_int_2 (low, high); + } +#endif + TREE_TYPE (t) = type; + force_fit_type (t, 0); + } +#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ + TREE_TYPE (t) = type; + } + else if (TREE_CODE (type) == REAL_TYPE) + { +#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) + if (TREE_CODE (arg1) == INTEGER_CST) + return build_real_from_int_cst (type, arg1); +#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ + if (TREE_CODE (arg1) == REAL_CST) + { + if (setjmp (float_error)) + { + pedwarn ("floating overflow in constant expression"); + return t; + } + set_float_handler (float_error); + + t = build_real (type, real_value_truncate (TYPE_MODE (type), + TREE_REAL_CST (arg1))); + set_float_handler (NULL_PTR); + return t; + } + } + TREE_CONSTANT (t) = 1; + return t; +} + +/* Return an expr equal to X but certainly not valid as an lvalue. + Also make sure it is not valid as an null pointer constant. */ + +tree +non_lvalue (x) + tree x; +{ + tree result; + + /* These things are certainly not lvalues. */ + if (TREE_CODE (x) == NON_LVALUE_EXPR + || TREE_CODE (x) == INTEGER_CST + || TREE_CODE (x) == REAL_CST + || TREE_CODE (x) == STRING_CST + || TREE_CODE (x) == ADDR_EXPR) + { + if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x)) + { + /* Use NOP_EXPR instead of NON_LVALUE_EXPR + so convert_for_assignment won't strip it. + This is so this 0 won't be treated as a null pointer constant. */ + result = build1 (NOP_EXPR, TREE_TYPE (x), x); + TREE_CONSTANT (result) = TREE_CONSTANT (x); + return result; + } + return x; + } + + result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x); + TREE_CONSTANT (result) = TREE_CONSTANT (x); + return result; +} + +/* Given a tree comparison code, return the code that is the logical inverse + of the given code. It is not safe to do this for floating-point + comparisons, except for NE_EXPR and EQ_EXPR. */ + +static enum tree_code +invert_tree_comparison (code) + enum tree_code code; +{ + switch (code) + { + case EQ_EXPR: + return NE_EXPR; + case NE_EXPR: + return EQ_EXPR; + case GT_EXPR: + return LE_EXPR; + case GE_EXPR: + return LT_EXPR; + case LT_EXPR: + return GE_EXPR; + case LE_EXPR: + return GT_EXPR; + default: + abort (); + } +} + +/* Similar, but return the comparison that results if the operands are + swapped. This is safe for floating-point. */ + +static enum tree_code +swap_tree_comparison (code) + enum tree_code code; +{ + switch (code) + { + case EQ_EXPR: + case NE_EXPR: + return code; + case GT_EXPR: + return LT_EXPR; + case GE_EXPR: + return LE_EXPR; + case LT_EXPR: + return GT_EXPR; + case LE_EXPR: + return GE_EXPR; + default: + abort (); + } +} + +/* Return nonzero if two operands are necessarily equal. + If ONLY_CONST is non-zero, only return non-zero for constants. + This function tests whether the operands are indistinguishable; + it does not test whether they are equal using C's == operation. + The distinction is important for IEEE floating point, because + (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and + (2) two NaNs may be indistinguishable, but NaN!=NaN. */ + +int +operand_equal_p (arg0, arg1, only_const) + tree arg0, arg1; + int only_const; +{ + /* If both types don't have the same signedness, then we can't consider + them equal. We must check this before the STRIP_NOPS calls + because they may change the signedness of the arguments. */ + if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1))) + return 0; + + STRIP_NOPS (arg0); + STRIP_NOPS (arg1); + + /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal. + We don't care about side effects in that case because the SAVE_EXPR + takes care of that for us. */ + if (TREE_CODE (arg0) == SAVE_EXPR && arg0 == arg1) + return ! only_const; + + if (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1)) + return 0; + + if (TREE_CODE (arg0) == TREE_CODE (arg1) + && TREE_CODE (arg0) == ADDR_EXPR + && TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0)) + return 1; + + if (TREE_CODE (arg0) == TREE_CODE (arg1) + && TREE_CODE (arg0) == INTEGER_CST + && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1) + && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1)) + return 1; + + /* Detect when real constants are equal. */ + if (TREE_CODE (arg0) == TREE_CODE (arg1) + && TREE_CODE (arg0) == REAL_CST) + return !bcmp (&TREE_REAL_CST (arg0), &TREE_REAL_CST (arg1), + sizeof (REAL_VALUE_TYPE)); + + if (only_const) + return 0; + + if (arg0 == arg1) + return 1; + + if (TREE_CODE (arg0) != TREE_CODE (arg1)) + return 0; + /* This is needed for conversions and for COMPONENT_REF. + Might as well play it safe and always test this. */ + if (TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1))) + return 0; + + switch (TREE_CODE_CLASS (TREE_CODE (arg0))) + { + case '1': + /* Two conversions are equal only if signedness and modes match. */ + if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR) + && (TREE_UNSIGNED (TREE_TYPE (arg0)) + != TREE_UNSIGNED (TREE_TYPE (arg1)))) + return 0; + + return operand_equal_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0), 0); + + case '<': + case '2': + return (operand_equal_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0), 0) + && operand_equal_p (TREE_OPERAND (arg0, 1), + TREE_OPERAND (arg1, 1), 0)); + + case 'r': + switch (TREE_CODE (arg0)) + { + case INDIRECT_REF: + return operand_equal_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0), 0); + + case COMPONENT_REF: + case ARRAY_REF: + return (operand_equal_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0), 0) + && operand_equal_p (TREE_OPERAND (arg0, 1), + TREE_OPERAND (arg1, 1), 0)); + + case BIT_FIELD_REF: + return (operand_equal_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0), 0) + && operand_equal_p (TREE_OPERAND (arg0, 1), + TREE_OPERAND (arg1, 1), 0) + && operand_equal_p (TREE_OPERAND (arg0, 2), + TREE_OPERAND (arg1, 2), 0)); + } + break; + } + + return 0; +} + +/* Similar to operand_equal_p, but see if ARG0 might have been made by + shorten_compare from ARG1 when ARG1 was being compared with OTHER. + + When in doubt, return 0. */ + +static int +operand_equal_for_comparison_p (arg0, arg1, other) + tree arg0, arg1; + tree other; +{ + int unsignedp1, unsignedpo; + tree primarg1, primother; + int correct_width; + + if (operand_equal_p (arg0, arg1, 0)) + return 1; + + if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))) + return 0; + + /* Duplicate what shorten_compare does to ARG1 and see if that gives the + actual comparison operand, ARG0. + + First throw away any conversions to wider types + already present in the operands. */ + + primarg1 = get_narrower (arg1, &unsignedp1); + primother = get_narrower (other, &unsignedpo); + + correct_width = TYPE_PRECISION (TREE_TYPE (arg1)); + if (unsignedp1 == unsignedpo + && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width + && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width) + { + tree type = TREE_TYPE (arg0); + + /* Make sure shorter operand is extended the right way + to match the longer operand. */ + primarg1 = convert (signed_or_unsigned_type (unsignedp1, + TREE_TYPE (primarg1)), + primarg1); + + if (operand_equal_p (arg0, convert (type, primarg1), 0)) + return 1; + } + + return 0; +} + +/* See if ARG is an expression that is either a comparison or is performing + arithmetic on comparisons. The comparisons must only be comparing + two different values, which will be stored in *CVAL1 and *CVAL2; if + they are non-zero it means that some operands have already been found. + No variables may be used anywhere else in the expression except in the + comparisons. + + If this is true, return 1. Otherwise, return zero. */ + +static int +twoval_comparison_p (arg, cval1, cval2) + tree arg; + tree *cval1, *cval2; +{ + enum tree_code code = TREE_CODE (arg); + char class = TREE_CODE_CLASS (code); + + /* We can handle some of the 'e' cases here. */ + if (class == 'e' + && (code == TRUTH_NOT_EXPR + || (code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0))) + class = '1'; + else if (class == 'e' + && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR + || code == COMPOUND_EXPR)) + class = '2'; + + switch (class) + { + case '1': + return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2); + + case '2': + return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2) + && twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2)); + + case 'c': + return 1; + + case 'e': + if (code == COND_EXPR) + return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2) + && twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2) + && twoval_comparison_p (TREE_OPERAND (arg, 2), + cval1, cval2)); + return 0; + + case '<': + /* First see if we can handle the first operand, then the second. For + the second operand, we know *CVAL1 can't be zero. It must be that + one side of the comparison is each of the values; test for the + case where this isn't true by failing if the two operands + are the same. */ + + if (operand_equal_p (TREE_OPERAND (arg, 0), + TREE_OPERAND (arg, 1), 0)) + return 0; + + if (*cval1 == 0) + *cval1 = TREE_OPERAND (arg, 0); + else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0)) + ; + else if (*cval2 == 0) + *cval2 = TREE_OPERAND (arg, 0); + else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0)) + ; + else + return 0; + + if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0)) + ; + else if (*cval2 == 0) + *cval2 = TREE_OPERAND (arg, 1); + else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0)) + ; + else + return 0; + + return 1; + } + + return 0; +} + +/* ARG is a tree that is known to contain just arithmetic operations and + comparisons. Evaluate the operations in the tree substituting NEW0 for + any occurrence of OLD0 as an operand of a comparison and likewise for + NEW1 and OLD1. */ + +static tree +eval_subst (arg, old0, new0, old1, new1) + tree arg; + tree old0, new0, old1, new1; +{ + tree type = TREE_TYPE (arg); + enum tree_code code = TREE_CODE (arg); + char class = TREE_CODE_CLASS (code); + + /* We can handle some of the 'e' cases here. */ + if (class == 'e' && code == TRUTH_NOT_EXPR) + class = '1'; + else if (class == 'e' + && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR)) + class = '2'; + + switch (class) + { + case '1': + return fold (build1 (code, type, + eval_subst (TREE_OPERAND (arg, 0), + old0, new0, old1, new1))); + + case '2': + return fold (build (code, type, + eval_subst (TREE_OPERAND (arg, 0), + old0, new0, old1, new1), + eval_subst (TREE_OPERAND (arg, 1), + old0, new0, old1, new1))); + + case 'e': + switch (code) + { + case SAVE_EXPR: + return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1); + + case COMPOUND_EXPR: + return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1); + + case COND_EXPR: + return fold (build (code, type, + eval_subst (TREE_OPERAND (arg, 0), + old0, new0, old1, new1), + eval_subst (TREE_OPERAND (arg, 1), + old0, new0, old1, new1), + eval_subst (TREE_OPERAND (arg, 2), + old0, new0, old1, new1))); + } + + case '<': + { + tree arg0 = TREE_OPERAND (arg, 0); + tree arg1 = TREE_OPERAND (arg, 1); + + /* We need to check both for exact equality and tree equality. The + former will be true if the operand has a side-effect. In that + case, we know the operand occurred exactly once. */ + + if (arg0 == old0 || operand_equal_p (arg0, old0, 0)) + arg0 = new0; + else if (arg0 == old1 || operand_equal_p (arg0, old1, 0)) + arg0 = new1; + + if (arg1 == old0 || operand_equal_p (arg1, old0, 0)) + arg1 = new0; + else if (arg1 == old1 || operand_equal_p (arg1, old1, 0)) + arg1 = new1; + + return fold (build (code, type, arg0, arg1)); + } + } + + return arg; +} + +/* Return a tree for the case when the result of an expression is RESULT + converted to TYPE and OMITTED was previously an operand of the expression + but is now not needed (e.g., we folded OMITTED * 0). + + If OMITTED has side effects, we must evaluate it. Otherwise, just do + the conversion of RESULT to TYPE. */ + +static tree +omit_one_operand (type, result, omitted) + tree type, result, omitted; +{ + tree t = convert (type, result); + + if (TREE_SIDE_EFFECTS (omitted)) + return build (COMPOUND_EXPR, type, omitted, t); + + return non_lvalue (t); +} + +/* Return a simplified tree node for the truth-negation of ARG. This + never alters ARG itself. We assume that ARG is an operation that + returns a truth value (0 or 1). */ + +tree +invert_truthvalue (arg) + tree arg; +{ + tree type = TREE_TYPE (arg); + enum tree_code code = TREE_CODE (arg); + + /* If this is a comparison, we can simply invert it, except for + floating-point non-equality comparisons, in which case we just + enclose a TRUTH_NOT_EXPR around what we have. */ + + if (TREE_CODE_CLASS (code) == '<') + { + if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0))) + && code != NE_EXPR && code != EQ_EXPR) + return build1 (TRUTH_NOT_EXPR, type, arg); + else + return build (invert_tree_comparison (code), type, + TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1)); + } + + switch (code) + { + case INTEGER_CST: + return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0 + && TREE_INT_CST_HIGH (arg) == 0, 0)); + + case TRUTH_AND_EXPR: + return build (TRUTH_OR_EXPR, type, + invert_truthvalue (TREE_OPERAND (arg, 0)), + invert_truthvalue (TREE_OPERAND (arg, 1))); + + case TRUTH_OR_EXPR: + return build (TRUTH_AND_EXPR, type, + invert_truthvalue (TREE_OPERAND (arg, 0)), + invert_truthvalue (TREE_OPERAND (arg, 1))); + + case TRUTH_XOR_EXPR: + /* Here we can invert either operand. We invert the first operand + unless the second operand is a TRUTH_NOT_EXPR in which case our + result is the XOR of the first operand with the inside of the + negation of the second operand. */ + + if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR) + return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0), + TREE_OPERAND (TREE_OPERAND (arg, 1), 0)); + else + return build (TRUTH_XOR_EXPR, type, + invert_truthvalue (TREE_OPERAND (arg, 0)), + TREE_OPERAND (arg, 1)); + + case TRUTH_ANDIF_EXPR: + return build (TRUTH_ORIF_EXPR, type, + invert_truthvalue (TREE_OPERAND (arg, 0)), + invert_truthvalue (TREE_OPERAND (arg, 1))); + + case TRUTH_ORIF_EXPR: + return build (TRUTH_ANDIF_EXPR, type, + invert_truthvalue (TREE_OPERAND (arg, 0)), + invert_truthvalue (TREE_OPERAND (arg, 1))); + + case TRUTH_NOT_EXPR: + return TREE_OPERAND (arg, 0); + + case COND_EXPR: + return build (COND_EXPR, type, TREE_OPERAND (arg, 0), + invert_truthvalue (TREE_OPERAND (arg, 1)), + invert_truthvalue (TREE_OPERAND (arg, 2))); + + case COMPOUND_EXPR: + return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0), + invert_truthvalue (TREE_OPERAND (arg, 1))); + + case NON_LVALUE_EXPR: + return invert_truthvalue (TREE_OPERAND (arg, 0)); + + case NOP_EXPR: + case CONVERT_EXPR: + case FLOAT_EXPR: + return build1 (TREE_CODE (arg), type, + invert_truthvalue (TREE_OPERAND (arg, 0))); + + case BIT_AND_EXPR: + if (! integer_onep (TREE_OPERAND (arg, 1))) + abort (); + return build (EQ_EXPR, type, arg, convert (type, integer_zero_node)); + } + + abort (); +} + +/* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both + operands are another bit-wise operation with a common input. If so, + distribute the bit operations to save an operation and possibly two if + constants are involved. For example, convert + (A | B) & (A | C) into A | (B & C) + Further simplification will occur if B and C are constants. + + If this optimization cannot be done, 0 will be returned. */ + +static tree +distribute_bit_expr (code, type, arg0, arg1) + enum tree_code code; + tree type; + tree arg0, arg1; +{ + tree common; + tree left, right; + + if (TREE_CODE (arg0) != TREE_CODE (arg1) + || TREE_CODE (arg0) == code + || (TREE_CODE (arg0) != BIT_AND_EXPR + && TREE_CODE (arg0) != BIT_IOR_EXPR)) + return 0; + + if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)) + { + common = TREE_OPERAND (arg0, 0); + left = TREE_OPERAND (arg0, 1); + right = TREE_OPERAND (arg1, 1); + } + else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0)) + { + common = TREE_OPERAND (arg0, 0); + left = TREE_OPERAND (arg0, 1); + right = TREE_OPERAND (arg1, 0); + } + else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0)) + { + common = TREE_OPERAND (arg0, 1); + left = TREE_OPERAND (arg0, 0); + right = TREE_OPERAND (arg1, 1); + } + else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0)) + { + common = TREE_OPERAND (arg0, 1); + left = TREE_OPERAND (arg0, 0); + right = TREE_OPERAND (arg1, 0); + } + else + return 0; + + return fold (build (TREE_CODE (arg0), type, common, + fold (build (code, type, left, right)))); +} + +/* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER + starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */ + +static tree +make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp) + tree inner; + tree type; + int bitsize, bitpos; + int unsignedp; +{ + tree result = build (BIT_FIELD_REF, type, inner, + size_int (bitsize), size_int (bitpos)); + + TREE_UNSIGNED (result) = unsignedp; + + return result; +} + +/* Optimize a bit-field compare. + + There are two cases: First is a compare against a constant and the + second is a comparison of two items where the fields are at the same + bit position relative to the start of a chunk (byte, halfword, word) + large enough to contain it. In these cases we can avoid the shift + implicit in bitfield extractions. + + For constants, we emit a compare of the shifted constant with the + BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being + compared. For two fields at the same position, we do the ANDs with the + similar mask and compare the result of the ANDs. + + CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR. + COMPARE_TYPE is the type of the comparison, and LHS and RHS + are the left and right operands of the comparison, respectively. + + If the optimization described above can be done, we return the resulting + tree. Otherwise we return zero. */ + +static tree +optimize_bit_field_compare (code, compare_type, lhs, rhs) + enum tree_code code; + tree compare_type; + tree lhs, rhs; +{ + int lbitpos, lbitsize, rbitpos, rbitsize; + int lnbitpos, lnbitsize, rnbitpos, rnbitsize; + tree type = TREE_TYPE (lhs); + tree signed_type, unsigned_type; + int const_p = TREE_CODE (rhs) == INTEGER_CST; + enum machine_mode lmode, rmode, lnmode, rnmode; + int lunsignedp, runsignedp; + int lvolatilep = 0, rvolatilep = 0; + tree linner, rinner; + tree mask; + tree offset; + + /* Get all the information about the extractions being done. If the bit size + if the same as the size of the underlying object, we aren't doing an + extraction at all and so can do nothing. */ + linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode, + &lunsignedp, &lvolatilep); + if (lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0 + || offset != 0) + return 0; + + if (!const_p) + { + /* If this is not a constant, we can only do something if bit positions, + sizes, and signedness are the same. */ + rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, + &rmode, &runsignedp, &rvolatilep); + + if (lbitpos != rbitpos || lbitsize != rbitsize + || lunsignedp != runsignedp || offset != 0) + return 0; + } + + /* See if we can find a mode to refer to this field. We should be able to, + but fail if we can't. */ + lnmode = get_best_mode (lbitsize, lbitpos, + TYPE_ALIGN (TREE_TYPE (linner)), word_mode, + lvolatilep); + if (lnmode == VOIDmode) + return 0; + + /* Set signed and unsigned types of the precision of this mode for the + shifts below. */ + signed_type = type_for_mode (lnmode, 0); + unsigned_type = type_for_mode (lnmode, 1); + + if (! const_p) + { + rnmode = get_best_mode (rbitsize, rbitpos, + TYPE_ALIGN (TREE_TYPE (rinner)), word_mode, + rvolatilep); + if (rnmode == VOIDmode) + return 0; + } + + /* Compute the bit position and size for the new reference and our offset + within it. If the new reference is the same size as the original, we + won't optimize anything, so return zero. */ + lnbitsize = GET_MODE_BITSIZE (lnmode); + lnbitpos = lbitpos & ~ (lnbitsize - 1); + lbitpos -= lnbitpos; + if (lnbitsize == lbitsize) + return 0; + + if (! const_p) + { + rnbitsize = GET_MODE_BITSIZE (rnmode); + rnbitpos = rbitpos & ~ (rnbitsize - 1); + rbitpos -= rnbitpos; + if (rnbitsize == rbitsize) + return 0; + } + +#if BYTES_BIG_ENDIAN + lbitpos = lnbitsize - lbitsize - lbitpos; +#endif + + /* Make the mask to be used against the extracted field. */ + mask = build_int_2 (~0, ~0); + TREE_TYPE (mask) = unsigned_type; + force_fit_type (mask, 0); + mask = convert (unsigned_type, mask); + mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0); + mask = const_binop (RSHIFT_EXPR, mask, + size_int (lnbitsize - lbitsize - lbitpos), 0); + + if (! const_p) + /* If not comparing with constant, just rework the comparison + and return. */ + return build (code, compare_type, + build (BIT_AND_EXPR, unsigned_type, + make_bit_field_ref (linner, unsigned_type, + lnbitsize, lnbitpos, 1), + mask), + build (BIT_AND_EXPR, unsigned_type, + make_bit_field_ref (rinner, unsigned_type, + rnbitsize, rnbitpos, 1), + mask)); + + /* Otherwise, we are handling the constant case. See if the constant is too + big for the field. Warn and return a tree of for 0 (false) if so. We do + this not only for its own sake, but to avoid having to test for this + error case below. If we didn't, we might generate wrong code. + + For unsigned fields, the constant shifted right by the field length should + be all zero. For signed fields, the high-order bits should agree with + the sign bit. */ + + if (lunsignedp) + { + if (! integer_zerop (const_binop (RSHIFT_EXPR, + convert (unsigned_type, rhs), + size_int (lbitsize), 0))) + { + warning ("comparison is always %s due to width of bitfield", + code == NE_EXPR ? "one" : "zero"); + return convert (compare_type, + (code == NE_EXPR + ? integer_one_node : integer_zero_node)); + } + } + else + { + tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs), + size_int (lbitsize - 1), 0); + if (! integer_zerop (tem) && ! integer_all_onesp (tem)) + { + warning ("comparison is always %s due to width of bitfield", + code == NE_EXPR ? "one" : "zero"); + return convert (compare_type, + (code == NE_EXPR + ? integer_one_node : integer_zero_node)); + } + } + + /* Single-bit compares should always be against zero. */ + if (lbitsize == 1 && ! integer_zerop (rhs)) + { + code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR; + rhs = convert (type, integer_zero_node); + } + + /* Make a new bitfield reference, shift the constant over the + appropriate number of bits and mask it with the computed mask + (in case this was a signed field). If we changed it, make a new one. */ + lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1); + + rhs = fold (const_binop (BIT_AND_EXPR, + const_binop (LSHIFT_EXPR, + convert (unsigned_type, rhs), + size_int (lbitpos), 0), + mask, 0)); + + return build (code, compare_type, + build (BIT_AND_EXPR, unsigned_type, lhs, mask), + rhs); +} + +/* Subroutine for fold_truthop: decode a field reference. + + If EXP is a comparison reference, we return the innermost reference. + + *PBITSIZE is set to the number of bits in the reference, *PBITPOS is + set to the starting bit number. + + If the innermost field can be completely contained in a mode-sized + unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode. + + *PVOLATILEP is set to 1 if the any expression encountered is volatile; + otherwise it is not changed. + + *PUNSIGNEDP is set to the signedness of the field. + + *PMASK is set to the mask used. This is either contained in a + BIT_AND_EXPR or derived from the width of the field. + + Return 0 if this is not a component reference or is one that we can't + do anything with. */ + +static tree +decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp, + pvolatilep, pmask) + tree exp; + int *pbitsize, *pbitpos; + enum machine_mode *pmode; + int *punsignedp, *pvolatilep; + tree *pmask; +{ + tree mask = 0; + tree inner; + tree offset; + + /* All the optimizations using this function assume integer fields. + There are problems with FP fields since the type_for_size call + below can fail for, e.g., XFmode. */ + if (! INTEGRAL_TYPE_P (TREE_TYPE (exp))) + return 0; + + STRIP_NOPS (exp); + + if (TREE_CODE (exp) == BIT_AND_EXPR) + { + mask = TREE_OPERAND (exp, 1); + exp = TREE_OPERAND (exp, 0); + STRIP_NOPS (exp); STRIP_NOPS (mask); + if (TREE_CODE (mask) != INTEGER_CST) + return 0; + } + + if (TREE_CODE (exp) != COMPONENT_REF && TREE_CODE (exp) != ARRAY_REF + && TREE_CODE (exp) != BIT_FIELD_REF) + return 0; + + inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode, + punsignedp, pvolatilep); + if (*pbitsize < 0 || offset != 0) + return 0; + + if (mask == 0) + { + tree unsigned_type = type_for_size (*pbitsize, 1); + int precision = TYPE_PRECISION (unsigned_type); + + mask = build_int_2 (~0, ~0); + TREE_TYPE (mask) = unsigned_type; + force_fit_type (mask, 0); + mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0); + mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0); + } + + *pmask = mask; + return inner; +} + +/* Return non-zero if MASK represents a mask of SIZE ones in the low-order + bit positions. */ + +static int +all_ones_mask_p (mask, size) + tree mask; + int size; +{ + tree type = TREE_TYPE (mask); + int precision = TYPE_PRECISION (type); + tree tmask; + + tmask = build_int_2 (~0, ~0); + TREE_TYPE (tmask) = signed_type (type); + force_fit_type (tmask, 0); + return + operand_equal_p (mask, + const_binop (RSHIFT_EXPR, + const_binop (LSHIFT_EXPR, tmask, + size_int (precision - size), 0), + size_int (precision - size), 0), + 0); +} + +/* Subroutine for fold_truthop: determine if an operand is simple enough + to be evaluated unconditionally. */ + +#ifdef __GNUC__ +__inline +#endif +static int +simple_operand_p (exp) + tree exp; +{ + /* Strip any conversions that don't change the machine mode. */ + while ((TREE_CODE (exp) == NOP_EXPR + || TREE_CODE (exp) == CONVERT_EXPR) + && (TYPE_MODE (TREE_TYPE (exp)) + == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0))))) + exp = TREE_OPERAND (exp, 0); + + return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c' + || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd' + && ! TREE_ADDRESSABLE (exp) + && ! TREE_THIS_VOLATILE (exp) + && ! DECL_NONLOCAL (exp) + /* Don't regard global variables as simple. They may be + allocated in ways unknown to the compiler (shared memory, + #pragma weak, etc). */ + && ! TREE_PUBLIC (exp) + && ! DECL_EXTERNAL (exp) + /* Loading a static variable is unduly expensive, but global + registers aren't expensive. */ + && (! TREE_STATIC (exp) || DECL_REGISTER (exp)))); +} + +/* Subroutine for fold_truthop: try to optimize a range test. + + For example, "i >= 2 && i =< 9" can be done as "(unsigned) (i - 2) <= 7". + + JCODE is the logical combination of the two terms. It is TRUTH_AND_EXPR + (representing TRUTH_ANDIF_EXPR and TRUTH_AND_EXPR) or TRUTH_OR_EXPR + (representing TRUTH_ORIF_EXPR and TRUTH_OR_EXPR). TYPE is the type of + the result. + + VAR is the value being tested. LO_CODE and HI_CODE are the comparison + operators comparing VAR to LO_CST and HI_CST. LO_CST is known to be no + larger than HI_CST (they may be equal). + + We return the simplified tree or 0 if no optimization is possible. */ + +tree +range_test (jcode, type, lo_code, hi_code, var, lo_cst, hi_cst) + enum tree_code jcode, lo_code, hi_code; + tree type, var, lo_cst, hi_cst; +{ + tree utype; + enum tree_code rcode; + + /* See if this is a range test and normalize the constant terms. */ + + if (jcode == TRUTH_AND_EXPR) + { + switch (lo_code) + { + case NE_EXPR: + /* See if we have VAR != CST && VAR != CST+1. */ + if (! (hi_code == NE_EXPR + && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1 + && tree_int_cst_equal (integer_one_node, + const_binop (MINUS_EXPR, + hi_cst, lo_cst, 0)))) + return 0; + + rcode = GT_EXPR; + break; + + case GT_EXPR: + case GE_EXPR: + if (hi_code == LT_EXPR) + hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0); + else if (hi_code != LE_EXPR) + return 0; + + if (lo_code == GT_EXPR) + lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0); + + /* We now have VAR >= LO_CST && VAR <= HI_CST. */ + rcode = LE_EXPR; + break; + + default: + return 0; + } + } + else + { + switch (lo_code) + { + case EQ_EXPR: + /* See if we have VAR == CST || VAR == CST+1. */ + if (! (hi_code == EQ_EXPR + && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1 + && tree_int_cst_equal (integer_one_node, + const_binop (MINUS_EXPR, + hi_cst, lo_cst, 0)))) + return 0; + + rcode = LE_EXPR; + break; + + case LE_EXPR: + case LT_EXPR: + if (hi_code == GE_EXPR) + hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0); + else if (hi_code != GT_EXPR) + return 0; + + if (lo_code == LE_EXPR) + lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0); + + /* We now have VAR < LO_CST || VAR > HI_CST. */ + rcode = GT_EXPR; + break; + + default: + return 0; + } + } + + /* When normalizing, it is possible to both increment the smaller constant + and decrement the larger constant. See if they are still ordered. */ + if (tree_int_cst_lt (hi_cst, lo_cst)) + return 0; + + /* Fail if VAR isn't an integer. */ + utype = TREE_TYPE (var); + if (! INTEGRAL_TYPE_P (utype)) + return 0; + + /* The range test is invalid if subtracting the two constants results + in overflow. This can happen in traditional mode. */ + if (! int_fits_type_p (hi_cst, TREE_TYPE (var)) + || ! int_fits_type_p (lo_cst, TREE_TYPE (var))) + return 0; + + if (! TREE_UNSIGNED (utype)) + { + utype = unsigned_type (utype); + var = convert (utype, var); + lo_cst = convert (utype, lo_cst); + hi_cst = convert (utype, hi_cst); + } + + return fold (convert (type, + build (rcode, utype, + build (MINUS_EXPR, utype, var, lo_cst), + const_binop (MINUS_EXPR, hi_cst, lo_cst, 0)))); +} + +/* Find ways of folding logical expressions of LHS and RHS: + Try to merge two comparisons to the same innermost item. + Look for range tests like "ch >= '0' && ch <= '9'". + Look for combinations of simple terms on machines with expensive branches + and evaluate the RHS unconditionally. + + For example, if we have p->a == 2 && p->b == 4 and we can make an + object large enough to span both A and B, we can do this with a comparison + against the object ANDed with the a mask. + + If we have p->a == q->a && p->b == q->b, we may be able to use bit masking + operations to do this with one comparison. + + We check for both normal comparisons and the BIT_AND_EXPRs made this by + function and the one above. + + CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR, + TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR. + + TRUTH_TYPE is the type of the logical operand and LHS and RHS are its + two operands. + + We return the simplified tree or 0 if no optimization is possible. */ + +static tree +fold_truthop (code, truth_type, lhs, rhs) + enum tree_code code; + tree truth_type, lhs, rhs; +{ + /* If this is the "or" of two comparisons, we can do something if we + the comparisons are NE_EXPR. If this is the "and", we can do something + if the comparisons are EQ_EXPR. I.e., + (a->b == 2 && a->c == 4) can become (a->new == NEW). + + WANTED_CODE is this operation code. For single bit fields, we can + convert EQ_EXPR to NE_EXPR so we need not reject the "wrong" + comparison for one-bit fields. */ + + enum tree_code wanted_code; + enum tree_code lcode, rcode; + tree ll_arg, lr_arg, rl_arg, rr_arg; + tree ll_inner, lr_inner, rl_inner, rr_inner; + int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos; + int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos; + int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos; + int lnbitsize, lnbitpos, rnbitsize, rnbitpos; + int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp; + enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode; + enum machine_mode lnmode, rnmode; + tree ll_mask, lr_mask, rl_mask, rr_mask; + tree l_const, r_const; + tree type, result; + int first_bit, end_bit; + int volatilep; + + /* Start by getting the comparison codes and seeing if this looks like + a range test. Fail if anything is volatile. */ + + if (TREE_SIDE_EFFECTS (lhs) + || TREE_SIDE_EFFECTS (rhs)) + return 0; + + lcode = TREE_CODE (lhs); + rcode = TREE_CODE (rhs); + + if (TREE_CODE_CLASS (lcode) != '<' + || TREE_CODE_CLASS (rcode) != '<') + return 0; + + code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR) + ? TRUTH_AND_EXPR : TRUTH_OR_EXPR); + + ll_arg = TREE_OPERAND (lhs, 0); + lr_arg = TREE_OPERAND (lhs, 1); + rl_arg = TREE_OPERAND (rhs, 0); + rr_arg = TREE_OPERAND (rhs, 1); + + if (TREE_CODE (lr_arg) == INTEGER_CST + && TREE_CODE (rr_arg) == INTEGER_CST + && operand_equal_p (ll_arg, rl_arg, 0)) + { + if (tree_int_cst_lt (lr_arg, rr_arg)) + result = range_test (code, truth_type, lcode, rcode, + ll_arg, lr_arg, rr_arg); + else + result = range_test (code, truth_type, rcode, lcode, + ll_arg, rr_arg, lr_arg); + + /* If this isn't a range test, it also isn't a comparison that + can be merged. However, it wins to evaluate the RHS unconditionally + on machines with expensive branches. */ + + if (result == 0 && BRANCH_COST >= 2) + { + if (TREE_CODE (ll_arg) != VAR_DECL + && TREE_CODE (ll_arg) != PARM_DECL) + { + /* Avoid evaluating the variable part twice. */ + ll_arg = save_expr (ll_arg); + lhs = build (lcode, TREE_TYPE (lhs), ll_arg, lr_arg); + rhs = build (rcode, TREE_TYPE (rhs), ll_arg, rr_arg); + } + return build (code, truth_type, lhs, rhs); + } + return result; + } + + /* If the RHS can be evaluated unconditionally and its operands are + simple, it wins to evaluate the RHS unconditionally on machines + with expensive branches. In this case, this isn't a comparison + that can be merged. */ + + /* @@ I'm not sure it wins on the m88110 to do this if the comparisons + are with zero (tmw). */ + + if (BRANCH_COST >= 2 + && INTEGRAL_TYPE_P (TREE_TYPE (rhs)) + && simple_operand_p (rl_arg) + && simple_operand_p (rr_arg)) + return build (code, truth_type, lhs, rhs); + + /* See if the comparisons can be merged. Then get all the parameters for + each side. */ + + if ((lcode != EQ_EXPR && lcode != NE_EXPR) + || (rcode != EQ_EXPR && rcode != NE_EXPR)) + return 0; + + volatilep = 0; + ll_inner = decode_field_reference (ll_arg, + &ll_bitsize, &ll_bitpos, &ll_mode, + &ll_unsignedp, &volatilep, &ll_mask); + lr_inner = decode_field_reference (lr_arg, + &lr_bitsize, &lr_bitpos, &lr_mode, + &lr_unsignedp, &volatilep, &lr_mask); + rl_inner = decode_field_reference (rl_arg, + &rl_bitsize, &rl_bitpos, &rl_mode, + &rl_unsignedp, &volatilep, &rl_mask); + rr_inner = decode_field_reference (rr_arg, + &rr_bitsize, &rr_bitpos, &rr_mode, + &rr_unsignedp, &volatilep, &rr_mask); + + /* It must be true that the inner operation on the lhs of each + comparison must be the same if we are to be able to do anything. + Then see if we have constants. If not, the same must be true for + the rhs's. */ + if (volatilep || ll_inner == 0 || rl_inner == 0 + || ! operand_equal_p (ll_inner, rl_inner, 0)) + return 0; + + if (TREE_CODE (lr_arg) == INTEGER_CST + && TREE_CODE (rr_arg) == INTEGER_CST) + l_const = lr_arg, r_const = rr_arg; + else if (lr_inner == 0 || rr_inner == 0 + || ! operand_equal_p (lr_inner, rr_inner, 0)) + return 0; + else + l_const = r_const = 0; + + /* If either comparison code is not correct for our logical operation, + fail. However, we can convert a one-bit comparison against zero into + the opposite comparison against that bit being set in the field. */ + + wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR); + if (lcode != wanted_code) + { + if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask)) + l_const = ll_mask; + else + return 0; + } + + if (rcode != wanted_code) + { + if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask)) + r_const = rl_mask; + else + return 0; + } + + /* See if we can find a mode that contains both fields being compared on + the left. If we can't, fail. Otherwise, update all constants and masks + to be relative to a field of that size. */ + first_bit = MIN (ll_bitpos, rl_bitpos); + end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize); + lnmode = get_best_mode (end_bit - first_bit, first_bit, + TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode, + volatilep); + if (lnmode == VOIDmode) + return 0; + + lnbitsize = GET_MODE_BITSIZE (lnmode); + lnbitpos = first_bit & ~ (lnbitsize - 1); + type = type_for_size (lnbitsize, 1); + xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos; + +#if BYTES_BIG_ENDIAN + xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize; + xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize; +#endif + + ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask), + size_int (xll_bitpos), 0); + rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask), + size_int (xrl_bitpos), 0); + + /* Make sure the constants are interpreted as unsigned, so we + don't have sign bits outside the range of their type. */ + + if (l_const) + { + l_const = convert (unsigned_type (TREE_TYPE (l_const)), l_const); + l_const = const_binop (LSHIFT_EXPR, convert (type, l_const), + size_int (xll_bitpos), 0); + } + if (r_const) + { + r_const = convert (unsigned_type (TREE_TYPE (r_const)), r_const); + r_const = const_binop (LSHIFT_EXPR, convert (type, r_const), + size_int (xrl_bitpos), 0); + } + + /* If the right sides are not constant, do the same for it. Also, + disallow this optimization if a size or signedness mismatch occurs + between the left and right sides. */ + if (l_const == 0) + { + if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize + || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp + /* Make sure the two fields on the right + correspond to the left without being swapped. */ + || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos) + return 0; + + first_bit = MIN (lr_bitpos, rr_bitpos); + end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize); + rnmode = get_best_mode (end_bit - first_bit, first_bit, + TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode, + volatilep); + if (rnmode == VOIDmode) + return 0; + + rnbitsize = GET_MODE_BITSIZE (rnmode); + rnbitpos = first_bit & ~ (rnbitsize - 1); + xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos; + +#if BYTES_BIG_ENDIAN + xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize; + xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize; +#endif + + lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask), + size_int (xlr_bitpos), 0); + rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask), + size_int (xrr_bitpos), 0); + + /* Make a mask that corresponds to both fields being compared. + Do this for both items being compared. If the masks agree, + we can do this by masking both and comparing the masked + results. */ + ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0); + lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0); + if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize) + { + lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos, + ll_unsignedp || rl_unsignedp); + rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos, + lr_unsignedp || rr_unsignedp); + if (! all_ones_mask_p (ll_mask, lnbitsize)) + { + lhs = build (BIT_AND_EXPR, type, lhs, ll_mask); + rhs = build (BIT_AND_EXPR, type, rhs, ll_mask); + } + return build (wanted_code, truth_type, lhs, rhs); + } + + /* There is still another way we can do something: If both pairs of + fields being compared are adjacent, we may be able to make a wider + field containing them both. */ + if ((ll_bitsize + ll_bitpos == rl_bitpos + && lr_bitsize + lr_bitpos == rr_bitpos) + || (ll_bitpos == rl_bitpos + rl_bitsize + && lr_bitpos == rr_bitpos + rr_bitsize)) + return build (wanted_code, truth_type, + make_bit_field_ref (ll_inner, type, + ll_bitsize + rl_bitsize, + MIN (ll_bitpos, rl_bitpos), + ll_unsignedp), + make_bit_field_ref (lr_inner, type, + lr_bitsize + rr_bitsize, + MIN (lr_bitpos, rr_bitpos), + lr_unsignedp)); + + return 0; + } + + /* Handle the case of comparisons with constants. If there is something in + common between the masks, those bits of the constants must be the same. + If not, the condition is always false. Test for this to avoid generating + incorrect code below. */ + result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0); + if (! integer_zerop (result) + && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0), + const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1) + { + if (wanted_code == NE_EXPR) + { + warning ("`or' of unmatched not-equal tests is always 1"); + return convert (truth_type, integer_one_node); + } + else + { + warning ("`and' of mutually exclusive equal-tests is always zero"); + return convert (truth_type, integer_zero_node); + } + } + + /* Construct the expression we will return. First get the component + reference we will make. Unless the mask is all ones the width of + that field, perform the mask operation. Then compare with the + merged constant. */ + result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos, + ll_unsignedp || rl_unsignedp); + + ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0); + if (! all_ones_mask_p (ll_mask, lnbitsize)) + result = build (BIT_AND_EXPR, type, result, ll_mask); + + return build (wanted_code, truth_type, result, + const_binop (BIT_IOR_EXPR, l_const, r_const, 0)); +} + +/* Perform constant folding and related simplification of EXPR. + The related simplifications include x*1 => x, x*0 => 0, etc., + and application of the associative law. + NOP_EXPR conversions may be removed freely (as long as we + are careful not to change the C type of the overall expression) + We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR, + but we can constant-fold them if they have constant operands. */ + +tree +fold (expr) + tree expr; +{ + register tree t = expr; + tree t1 = NULL_TREE; + tree tem; + tree type = TREE_TYPE (expr); + register tree arg0, arg1; + register enum tree_code code = TREE_CODE (t); + register int kind; + int invert; + + /* WINS will be nonzero when the switch is done + if all operands are constant. */ + + int wins = 1; + + /* Return right away if already constant. */ + if (TREE_CONSTANT (t)) + { + if (code == CONST_DECL) + return DECL_INITIAL (t); + return t; + } + + kind = TREE_CODE_CLASS (code); + if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR) + { + tree subop; + + /* Special case for conversion ops that can have fixed point args. */ + arg0 = TREE_OPERAND (t, 0); + + /* Don't use STRIP_NOPS, because signedness of argument type matters. */ + if (arg0 != 0) + STRIP_TYPE_NOPS (arg0); + + if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST) + subop = TREE_REALPART (arg0); + else + subop = arg0; + + if (subop != 0 && TREE_CODE (subop) != INTEGER_CST +#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) + && TREE_CODE (subop) != REAL_CST +#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ + ) + /* Note that TREE_CONSTANT isn't enough: + static var addresses are constant but we can't + do arithmetic on them. */ + wins = 0; + } + else if (kind == 'e' || kind == '<' + || kind == '1' || kind == '2' || kind == 'r') + { + register int len = tree_code_length[(int) code]; + register int i; + for (i = 0; i < len; i++) + { + tree op = TREE_OPERAND (t, i); + tree subop; + + if (op == 0) + continue; /* Valid for CALL_EXPR, at least. */ + + if (kind == '<' || code == RSHIFT_EXPR) + { + /* Signedness matters here. Perhaps we can refine this + later. */ + STRIP_TYPE_NOPS (op); + } + else + { + /* Strip any conversions that don't change the mode. */ + STRIP_NOPS (op); + } + + if (TREE_CODE (op) == COMPLEX_CST) + subop = TREE_REALPART (op); + else + subop = op; + + if (TREE_CODE (subop) != INTEGER_CST +#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) + && TREE_CODE (subop) != REAL_CST +#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ + ) + /* Note that TREE_CONSTANT isn't enough: + static var addresses are constant but we can't + do arithmetic on them. */ + wins = 0; + + if (i == 0) + arg0 = op; + else if (i == 1) + arg1 = op; + } + } + + /* If this is a commutative operation, and ARG0 is a constant, move it + to ARG1 to reduce the number of tests below. */ + if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR + || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR + || code == BIT_AND_EXPR) + && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST)) + { + tem = arg0; arg0 = arg1; arg1 = tem; + + tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1); + TREE_OPERAND (t, 1) = tem; + } + + /* Now WINS is set as described above, + ARG0 is the first operand of EXPR, + and ARG1 is the second operand (if it has more than one operand). + + First check for cases where an arithmetic operation is applied to a + compound, conditional, or comparison operation. Push the arithmetic + operation inside the compound or conditional to see if any folding + can then be done. Convert comparison to conditional for this purpose. + The also optimizes non-constant cases that used to be done in + expand_expr. */ + if (TREE_CODE_CLASS (code) == '1') + { + if (TREE_CODE (arg0) == COMPOUND_EXPR) + return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), + fold (build1 (code, type, TREE_OPERAND (arg0, 1)))); + else if (TREE_CODE (arg0) == COND_EXPR) + { + t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0), + fold (build1 (code, type, TREE_OPERAND (arg0, 1))), + fold (build1 (code, type, TREE_OPERAND (arg0, 2))))); + + /* If this was a conversion, and all we did was to move into + inside the COND_EXPR, bring it back out. Then return so we + don't get into an infinite recursion loop taking the conversion + out and then back in. */ + + if ((code == NOP_EXPR || code == CONVERT_EXPR + || code == NON_LVALUE_EXPR) + && TREE_CODE (t) == COND_EXPR + && TREE_CODE (TREE_OPERAND (t, 1)) == code + && TREE_CODE (TREE_OPERAND (t, 2)) == code + && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)) + == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))) + t = build1 (code, type, + build (COND_EXPR, + TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)), + TREE_OPERAND (t, 0), + TREE_OPERAND (TREE_OPERAND (t, 1), 0), + TREE_OPERAND (TREE_OPERAND (t, 2), 0))); + return t; + } + else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<') + return fold (build (COND_EXPR, type, arg0, + fold (build1 (code, type, integer_one_node)), + fold (build1 (code, type, integer_zero_node)))); + } + else if (TREE_CODE_CLASS (code) == '2') + { + if (TREE_CODE (arg1) == COMPOUND_EXPR) + return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0), + fold (build (code, type, arg0, TREE_OPERAND (arg1, 1)))); + else if (TREE_CODE (arg1) == COND_EXPR + || TREE_CODE_CLASS (TREE_CODE (arg1)) == '<') + { + tree test, true_value, false_value; + + if (TREE_CODE (arg1) == COND_EXPR) + { + test = TREE_OPERAND (arg1, 0); + true_value = TREE_OPERAND (arg1, 1); + false_value = TREE_OPERAND (arg1, 2); + } + else + { + test = arg1; + true_value = integer_one_node; + false_value = integer_zero_node; + } + + if (TREE_CODE (arg0) != VAR_DECL && TREE_CODE (arg0) != PARM_DECL) + arg0 = save_expr (arg0); + test = fold (build (COND_EXPR, type, test, + fold (build (code, type, arg0, true_value)), + fold (build (code, type, arg0, false_value)))); + if (TREE_CODE (arg0) == SAVE_EXPR) + return build (COMPOUND_EXPR, type, + convert (void_type_node, arg0), test); + else + return convert (type, test); + } + + else if (TREE_CODE (arg0) == COMPOUND_EXPR) + return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), + fold (build (code, type, TREE_OPERAND (arg0, 1), arg1))); + else if (TREE_CODE (arg0) == COND_EXPR + || TREE_CODE_CLASS (TREE_CODE (arg0)) == '<') + { + tree test, true_value, false_value; + + if (TREE_CODE (arg0) == COND_EXPR) + { + test = TREE_OPERAND (arg0, 0); + true_value = TREE_OPERAND (arg0, 1); + false_value = TREE_OPERAND (arg0, 2); + } + else + { + test = arg0; + true_value = integer_one_node; + false_value = integer_zero_node; + } + + if (TREE_CODE (arg1) != VAR_DECL && TREE_CODE (arg1) != PARM_DECL) + arg1 = save_expr (arg1); + test = fold (build (COND_EXPR, type, test, + fold (build (code, type, true_value, arg1)), + fold (build (code, type, false_value, arg1)))); + if (TREE_CODE (arg1) == SAVE_EXPR) + return build (COMPOUND_EXPR, type, + convert (void_type_node, arg1), test); + else + return convert (type, test); + } + } + else if (TREE_CODE_CLASS (code) == '<' + && TREE_CODE (arg0) == COMPOUND_EXPR) + return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), + fold (build (code, type, TREE_OPERAND (arg0, 1), arg1))); + else if (TREE_CODE_CLASS (code) == '<' + && TREE_CODE (arg1) == COMPOUND_EXPR) + return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0), + fold (build (code, type, arg0, TREE_OPERAND (arg1, 1)))); + + switch (code) + { + case INTEGER_CST: + case REAL_CST: + case STRING_CST: + case COMPLEX_CST: + case CONSTRUCTOR: + return t; + + case CONST_DECL: + return fold (DECL_INITIAL (t)); + + case NOP_EXPR: + case FLOAT_EXPR: + case CONVERT_EXPR: + case FIX_TRUNC_EXPR: + /* Other kinds of FIX are not handled properly by fold_convert. */ + /* Two conversions in a row are not needed unless: + - the intermediate type is narrower than both initial and final, or + - the intermediate type and innermost type differ in signedness, + and the outermost type is wider than the intermediate, or + - the initial type is a pointer type and the precisions of the + intermediate and final types differ, or + - the final type is a pointer type and the precisions of the + initial and intermediate types differ. */ + if ((TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR + || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR) + && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) + > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) + || + TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) + > TYPE_PRECISION (TREE_TYPE (t))) + && ! ((TREE_CODE (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) + == INTEGER_TYPE) + && (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) + == INTEGER_TYPE) + && (TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (t, 0))) + != TREE_UNSIGNED (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) + && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) + < TYPE_PRECISION (TREE_TYPE (t)))) + && ((TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (t, 0))) + && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) + > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))))) + == + (TREE_UNSIGNED (TREE_TYPE (t)) + && (TYPE_PRECISION (TREE_TYPE (t)) + > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))))) + && ! ((TREE_CODE (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) + == POINTER_TYPE) + && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) + != TYPE_PRECISION (TREE_TYPE (t)))) + && ! (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE + && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) + != TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))))) + return convert (TREE_TYPE (t), TREE_OPERAND (TREE_OPERAND (t, 0), 0)); + + if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR + && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1)) + /* Detect assigning a bitfield. */ + && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF + && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1)))) + { + /* Don't leave an assignment inside a conversion + unless assigning a bitfield. */ + tree prev = TREE_OPERAND (t, 0); + TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1); + /* First do the assignment, then return converted constant. */ + t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t)); + TREE_USED (t) = 1; + return t; + } + if (!wins) + { + TREE_CONSTANT (t) = TREE_CONSTANT (arg0); + return t; + } + return fold_convert (t, arg0); + +#if 0 /* This loses on &"foo"[0]. */ + case ARRAY_REF: + { + int i; + + /* Fold an expression like: "foo"[2] */ + if (TREE_CODE (arg0) == STRING_CST + && TREE_CODE (arg1) == INTEGER_CST + && !TREE_INT_CST_HIGH (arg1) + && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0)) + { + t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0); + TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0)); + force_fit_type (t, 0); + } + } + return t; +#endif /* 0 */ + + case RANGE_EXPR: + TREE_CONSTANT (t) = wins; + return t; + + case NEGATE_EXPR: + if (wins) + { + if (TREE_CODE (arg0) == INTEGER_CST) + { + HOST_WIDE_INT low, high; + int overflow = neg_double (TREE_INT_CST_LOW (arg0), + TREE_INT_CST_HIGH (arg0), + &low, &high); + t = build_int_2 (low, high); + TREE_TYPE (t) = type; + TREE_CONSTANT_OVERFLOW (t) + = (TREE_CONSTANT_OVERFLOW (arg0) + | force_fit_type (t, overflow)); + } + else if (TREE_CODE (arg0) == REAL_CST) + t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); + TREE_TYPE (t) = type; + } + else if (TREE_CODE (arg0) == NEGATE_EXPR) + return TREE_OPERAND (arg0, 0); + + /* Convert - (a - b) to (b - a) for non-floating-point. */ + else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type)) + return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1), + TREE_OPERAND (arg0, 0)); + + return t; + + case ABS_EXPR: + if (wins) + { + if (TREE_CODE (arg0) == INTEGER_CST) + { + if (! TREE_UNSIGNED (type) + && TREE_INT_CST_HIGH (arg0) < 0) + { + HOST_WIDE_INT low, high; + int overflow = neg_double (TREE_INT_CST_LOW (arg0), + TREE_INT_CST_HIGH (arg0), + &low, &high); + t = build_int_2 (low, high); + TREE_TYPE (t) = type; + TREE_CONSTANT_OVERFLOW (t) + = (TREE_CONSTANT_OVERFLOW (arg0) + | force_fit_type (t, overflow)); + } + } + else if (TREE_CODE (arg0) == REAL_CST) + { + if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0))) + t = build_real (type, + REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); + } + TREE_TYPE (t) = type; + } + else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR) + return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0)); + return t; + + case BIT_NOT_EXPR: + if (wins) + { + if (TREE_CODE (arg0) == INTEGER_CST) + t = build_int_2 (~ TREE_INT_CST_LOW (arg0), + ~ TREE_INT_CST_HIGH (arg0)); + TREE_TYPE (t) = type; + force_fit_type (t, 0); + TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0); + } + else if (TREE_CODE (arg0) == BIT_NOT_EXPR) + return TREE_OPERAND (arg0, 0); + return t; + + case PLUS_EXPR: + /* A + (-B) -> A - B */ + if (TREE_CODE (arg1) == NEGATE_EXPR) + return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0))); + else if (! FLOAT_TYPE_P (type)) + { + if (integer_zerop (arg1)) + return non_lvalue (convert (type, arg0)); + + /* If we are adding two BIT_AND_EXPR's, both of which are and'ing + with a constant, and the two constants have no bits in common, + we should treat this as a BIT_IOR_EXPR since this may produce more + simplifications. */ + if (TREE_CODE (arg0) == BIT_AND_EXPR + && TREE_CODE (arg1) == BIT_AND_EXPR + && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST + && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST + && integer_zerop (const_binop (BIT_AND_EXPR, + TREE_OPERAND (arg0, 1), + TREE_OPERAND (arg1, 1), 0))) + { + code = BIT_IOR_EXPR; + goto bit_ior; + } + } + /* In IEEE floating point, x+0 may not equal x. */ + else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT + && real_zerop (arg1)) + return non_lvalue (convert (type, arg0)); + associate: + /* In most languages, can't associate operations on floats + through parentheses. Rather than remember where the parentheses + were, we don't associate floats at all. It shouldn't matter much. */ + if (FLOAT_TYPE_P (type)) + goto binary; + /* The varsign == -1 cases happen only for addition and subtraction. + It says that the arg that was split was really CON minus VAR. + The rest of the code applies to all associative operations. */ + if (!wins) + { + tree var, con; + int varsign; + + if (split_tree (arg0, code, &var, &con, &varsign)) + { + if (varsign == -1) + { + /* EXPR is (CON-VAR) +- ARG1. */ + /* If it is + and VAR==ARG1, return just CONST. */ + if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0)) + return convert (TREE_TYPE (t), con); + + /* If ARG0 is a constant, don't change things around; + instead keep all the constant computations together. */ + + if (TREE_CONSTANT (arg0)) + return t; + + /* Otherwise return (CON +- ARG1) - VAR. */ + TREE_SET_CODE (t, MINUS_EXPR); + TREE_OPERAND (t, 1) = var; + TREE_OPERAND (t, 0) + = fold (build (code, TREE_TYPE (t), con, arg1)); + } + else + { + /* EXPR is (VAR+CON) +- ARG1. */ + /* If it is - and VAR==ARG1, return just CONST. */ + if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0)) + return convert (TREE_TYPE (t), con); + + /* If ARG0 is a constant, don't change things around; + instead keep all the constant computations together. */ + + if (TREE_CONSTANT (arg0)) + return t; + + /* Otherwise return VAR +- (ARG1 +- CON). */ + TREE_OPERAND (t, 1) = tem + = fold (build (code, TREE_TYPE (t), arg1, con)); + TREE_OPERAND (t, 0) = var; + if (integer_zerop (tem) + && (code == PLUS_EXPR || code == MINUS_EXPR)) + return convert (type, var); + /* If we have x +/- (c - d) [c an explicit integer] + change it to x -/+ (d - c) since if d is relocatable + then the latter can be a single immediate insn + and the former cannot. */ + if (TREE_CODE (tem) == MINUS_EXPR + && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST) + { + tree tem1 = TREE_OPERAND (tem, 1); + TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0); + TREE_OPERAND (tem, 0) = tem1; + TREE_SET_CODE (t, + (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR)); + } + } + return t; + } + + if (split_tree (arg1, code, &var, &con, &varsign)) + { + /* EXPR is ARG0 +- (CON +- VAR). */ + if (TREE_CODE (t) == MINUS_EXPR + && operand_equal_p (var, arg0, 0)) + { + /* If VAR and ARG0 cancel, return just CON or -CON. */ + if (code == PLUS_EXPR) + return convert (TREE_TYPE (t), con); + return fold (build1 (NEGATE_EXPR, TREE_TYPE (t), + convert (TREE_TYPE (t), con))); + } + if (TREE_CONSTANT (arg1)) + return t; + if (varsign == -1) + TREE_SET_CODE (t, + (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR)); + TREE_OPERAND (t, 0) + = fold (build (code, TREE_TYPE (t), arg0, con)); + TREE_OPERAND (t, 1) = var; + if (integer_zerop (TREE_OPERAND (t, 0)) + && TREE_CODE (t) == PLUS_EXPR) + return convert (TREE_TYPE (t), var); + return t; + } + } + binary: +#if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC) + if (TREE_CODE (arg1) == REAL_CST) + return t; +#endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */ + if (wins) + t1 = const_binop (code, arg0, arg1, 0); + if (t1 != NULL_TREE) + { + /* The return value should always have + the same type as the original expression. */ + TREE_TYPE (t1) = TREE_TYPE (t); + return t1; + } + return t; + + case MINUS_EXPR: + if (! FLOAT_TYPE_P (type)) + { + if (! wins && integer_zerop (arg0)) + return build1 (NEGATE_EXPR, type, arg1); + if (integer_zerop (arg1)) + return non_lvalue (convert (type, arg0)); + } + /* Convert A - (-B) to A + B. */ + else if (TREE_CODE (arg1) == NEGATE_EXPR) + return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0))); + else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT) + { + /* Except with IEEE floating point, 0-x equals -x. */ + if (! wins && real_zerop (arg0)) + return build1 (NEGATE_EXPR, type, arg1); + /* Except with IEEE floating point, x-0 equals x. */ + if (real_zerop (arg1)) + return non_lvalue (convert (type, arg0)); + + /* Fold &x - &x. This can happen from &x.foo - &x. + This is unsafe for certain floats even in non-IEEE formats. + In IEEE, it is unsafe because it does wrong for NaNs. + Also note that operand_equal_p is always false if an operand + is volatile. */ + + if (operand_equal_p (arg0, arg1, FLOAT_TYPE_P (type))) + return convert (type, integer_zero_node); + } + goto associate; + + case MULT_EXPR: + if (! FLOAT_TYPE_P (type)) + { + if (integer_zerop (arg1)) + return omit_one_operand (type, arg1, arg0); + if (integer_onep (arg1)) + return non_lvalue (convert (type, arg0)); + + /* (a * (1 << b)) is (a << b) */ + if (TREE_CODE (arg1) == LSHIFT_EXPR + && integer_onep (TREE_OPERAND (arg1, 0))) + return fold (build (LSHIFT_EXPR, type, arg0, + TREE_OPERAND (arg1, 1))); + if (TREE_CODE (arg0) == LSHIFT_EXPR + && integer_onep (TREE_OPERAND (arg0, 0))) + return fold (build (LSHIFT_EXPR, type, arg1, + TREE_OPERAND (arg0, 1))); + } + else + { + /* x*0 is 0, except for IEEE floating point. */ + if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT + && real_zerop (arg1)) + return omit_one_operand (type, arg1, arg0); + /* In IEEE floating point, x*1 is not equivalent to x for snans. + However, ANSI says we can drop signals, + so we can do this anyway. */ + if (real_onep (arg1)) + return non_lvalue (convert (type, arg0)); + /* x*2 is x+x */ + if (! wins && real_twop (arg1)) + { + tree arg = save_expr (arg0); + return build (PLUS_EXPR, type, arg, arg); + } + } + goto associate; + + case BIT_IOR_EXPR: + bit_ior: + if (integer_all_onesp (arg1)) + return omit_one_operand (type, arg1, arg0); + if (integer_zerop (arg1)) + return non_lvalue (convert (type, arg0)); + t1 = distribute_bit_expr (code, type, arg0, arg1); + if (t1 != NULL_TREE) + return t1; + + /* (a << C1) | (a >> C2) if A is unsigned and C1+C2 is the size of A + is a rotate of A by C1 bits. */ + + if ((TREE_CODE (arg0) == RSHIFT_EXPR + || TREE_CODE (arg0) == LSHIFT_EXPR) + && (TREE_CODE (arg1) == RSHIFT_EXPR + || TREE_CODE (arg1) == LSHIFT_EXPR) + && TREE_CODE (arg0) != TREE_CODE (arg1) + && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0) + && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))) + && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST + && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST + && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0 + && TREE_INT_CST_HIGH (TREE_OPERAND (arg1, 1)) == 0 + && ((TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) + + TREE_INT_CST_LOW (TREE_OPERAND (arg1, 1))) + == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))))) + return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0), + TREE_CODE (arg0) == LSHIFT_EXPR + ? TREE_OPERAND (arg0, 1) : TREE_OPERAND (arg1, 1)); + + goto associate; + + case BIT_XOR_EXPR: + if (integer_zerop (arg1)) + return non_lvalue (convert (type, arg0)); + if (integer_all_onesp (arg1)) + return fold (build1 (BIT_NOT_EXPR, type, arg0)); + goto associate; + + case BIT_AND_EXPR: + bit_and: + if (integer_all_onesp (arg1)) + return non_lvalue (convert (type, arg0)); + if (integer_zerop (arg1)) + return omit_one_operand (type, arg1, arg0); + t1 = distribute_bit_expr (code, type, arg0, arg1); + if (t1 != NULL_TREE) + return t1; + /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */ + if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR + && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0)))) + { + int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0))); + if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT + && (~TREE_INT_CST_LOW (arg0) + & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0) + return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0)); + } + if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR + && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))) + { + int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))); + if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT + && (~TREE_INT_CST_LOW (arg1) + & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0) + return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0)); + } + goto associate; + + case BIT_ANDTC_EXPR: + if (integer_all_onesp (arg0)) + return non_lvalue (convert (type, arg1)); + if (integer_zerop (arg0)) + return omit_one_operand (type, arg0, arg1); + if (TREE_CODE (arg1) == INTEGER_CST) + { + arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1)); + code = BIT_AND_EXPR; + goto bit_and; + } + goto binary; + + case TRUNC_DIV_EXPR: + case ROUND_DIV_EXPR: + case FLOOR_DIV_EXPR: + case CEIL_DIV_EXPR: + case EXACT_DIV_EXPR: + case RDIV_EXPR: + if (integer_onep (arg1)) + return non_lvalue (convert (type, arg0)); + if (integer_zerop (arg1)) + return t; + + /* If we have ((a * C1) / C2) and C1 % C2 == 0, we can replace this with + (a * (C1/C2). Also look for when we have a SAVE_EXPR in + between. */ + if (TREE_CODE (arg1) == INTEGER_CST + && TREE_INT_CST_LOW (arg1) > 0 && TREE_INT_CST_HIGH (arg1) == 0 + && TREE_CODE (arg0) == MULT_EXPR + && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST + && TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) > 0 + && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0 + && 0 == (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) + % TREE_INT_CST_LOW (arg1))) + { + tree new_op + = build_int_2 (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) + / TREE_INT_CST_LOW (arg1), 0); + + TREE_TYPE (new_op) = type; + return build (MULT_EXPR, type, TREE_OPERAND (arg0, 0), new_op); + } + + else if (TREE_CODE (arg1) == INTEGER_CST + && TREE_INT_CST_LOW (arg1) > 0 && TREE_INT_CST_HIGH (arg1) == 0 + && TREE_CODE (arg0) == SAVE_EXPR + && TREE_CODE (TREE_OPERAND (arg0, 0)) == MULT_EXPR + && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)) + == INTEGER_CST) + && (TREE_INT_CST_LOW (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)) + > 0) + && (TREE_INT_CST_HIGH (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)) + == 0) + && (TREE_INT_CST_LOW (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)) + % TREE_INT_CST_LOW (arg1)) == 0) + { + tree new_op + = build_int_2 (TREE_INT_CST_LOW (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)) + / TREE_INT_CST_LOW (arg1), 0); + + TREE_TYPE (new_op) = type; + return build (MULT_EXPR, type, + TREE_OPERAND (TREE_OPERAND (arg0, 0), 0), new_op); + } + +#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) +#ifndef REAL_INFINITY + if (TREE_CODE (arg1) == REAL_CST + && real_zerop (arg1)) + return t; +#endif +#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ + + goto binary; + + case CEIL_MOD_EXPR: + case FLOOR_MOD_EXPR: + case ROUND_MOD_EXPR: + case TRUNC_MOD_EXPR: + if (integer_onep (arg1)) + return omit_one_operand (type, integer_zero_node, arg0); + if (integer_zerop (arg1)) + return t; + goto binary; + + case LSHIFT_EXPR: + case RSHIFT_EXPR: + case LROTATE_EXPR: + case RROTATE_EXPR: + if (integer_zerop (arg1)) + return non_lvalue (convert (type, arg0)); + /* Since negative shift count is not well-defined, + don't try to compute it in the compiler. */ + if (tree_int_cst_lt (arg1, integer_zero_node)) + return t; + goto binary; + + case MIN_EXPR: + if (operand_equal_p (arg0, arg1, 0)) + return arg0; + if (INTEGRAL_TYPE_P (type) + && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1)) + return omit_one_operand (type, arg1, arg0); + goto associate; + + case MAX_EXPR: + if (operand_equal_p (arg0, arg1, 0)) + return arg0; + if (INTEGRAL_TYPE_P (type) + && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1)) + return omit_one_operand (type, arg1, arg0); + goto associate; + + case TRUTH_NOT_EXPR: + /* Note that the operand of this must be an int + and its values must be 0 or 1. + ("true" is a fixed value perhaps depending on the language, + but we don't handle values other than 1 correctly yet.) */ + return invert_truthvalue (arg0); + + case TRUTH_ANDIF_EXPR: + /* Note that the operands of this must be ints + and their values must be 0 or 1. + ("true" is a fixed value perhaps depending on the language.) */ + /* If first arg is constant zero, return it. */ + if (integer_zerop (arg0)) + return arg0; + case TRUTH_AND_EXPR: + /* If either arg is constant true, drop it. */ + if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) + return non_lvalue (arg1); + if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)) + return non_lvalue (arg0); + /* If second arg is constant zero, result is zero, but first arg + must be evaluated. */ + if (integer_zerop (arg1)) + return omit_one_operand (type, arg1, arg0); + + truth_andor: + /* Check for the possibility of merging component references. If our + lhs is another similar operation, try to merge its rhs with our + rhs. Then try to merge our lhs and rhs. */ + if (optimize) + { + if (TREE_CODE (arg0) == code) + { + tem = fold_truthop (code, type, + TREE_OPERAND (arg0, 1), arg1); + if (tem) + return fold (build (code, type, TREE_OPERAND (arg0, 0), tem)); + } + + tem = fold_truthop (code, type, arg0, arg1); + if (tem) + return tem; + } + return t; + + case TRUTH_ORIF_EXPR: + /* Note that the operands of this must be ints + and their values must be 0 or true. + ("true" is a fixed value perhaps depending on the language.) */ + /* If first arg is constant true, return it. */ + if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) + return arg0; + case TRUTH_OR_EXPR: + /* If either arg is constant zero, drop it. */ + if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0)) + return non_lvalue (arg1); + if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)) + return non_lvalue (arg0); + /* If second arg is constant true, result is true, but we must + evaluate first arg. */ + if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)) + return omit_one_operand (type, arg1, arg0); + goto truth_andor; + + case TRUTH_XOR_EXPR: + /* If either arg is constant zero, drop it. */ + if (integer_zerop (arg0)) + return non_lvalue (arg1); + if (integer_zerop (arg1)) + return non_lvalue (arg0); + /* If either arg is constant true, this is a logical inversion. */ + if (integer_onep (arg0)) + return non_lvalue (invert_truthvalue (arg1)); + if (integer_onep (arg1)) + return non_lvalue (invert_truthvalue (arg0)); + break; + + case EQ_EXPR: + case NE_EXPR: + case LT_EXPR: + case GT_EXPR: + case LE_EXPR: + case GE_EXPR: + /* If one arg is a constant integer, put it last. */ + if (TREE_CODE (arg0) == INTEGER_CST + && TREE_CODE (arg1) != INTEGER_CST) + { + TREE_OPERAND (t, 0) = arg1; + TREE_OPERAND (t, 1) = arg0; + arg0 = TREE_OPERAND (t, 0); + arg1 = TREE_OPERAND (t, 1); + code = swap_tree_comparison (code); + TREE_SET_CODE (t, code); + } + + /* Convert foo++ == CONST into ++foo == CONST + INCR. + First, see if one arg is constant; find the constant arg + and the other one. */ + { + tree constop = 0, varop; + tree *constoploc; + + if (TREE_CONSTANT (arg1)) + constoploc = &TREE_OPERAND (t, 1), constop = arg1, varop = arg0; + if (TREE_CONSTANT (arg0)) + constoploc = &TREE_OPERAND (t, 0), constop = arg0, varop = arg1; + + if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR) + { + /* This optimization is invalid for ordered comparisons + if CONST+INCR overflows or if foo+incr might overflow. + This optimization is invalid for floating point due to rounding. + For pointer types we assume overflow doesn't happen. */ + if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE + || (! FLOAT_TYPE_P (TREE_TYPE (varop)) + && (code == EQ_EXPR || code == NE_EXPR))) + { + tree newconst + = fold (build (PLUS_EXPR, TREE_TYPE (varop), + constop, TREE_OPERAND (varop, 1))); + TREE_SET_CODE (varop, PREINCREMENT_EXPR); + *constoploc = newconst; + return t; + } + } + else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR) + { + if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE + || (! FLOAT_TYPE_P (TREE_TYPE (varop)) + && (code == EQ_EXPR || code == NE_EXPR))) + { + tree newconst + = fold (build (MINUS_EXPR, TREE_TYPE (varop), + constop, TREE_OPERAND (varop, 1))); + TREE_SET_CODE (varop, PREDECREMENT_EXPR); + *constoploc = newconst; + return t; + } + } + } + + /* Change X >= CST to X > (CST - 1) if CST is positive. */ + if (TREE_CODE (arg1) == INTEGER_CST + && TREE_CODE (arg0) != INTEGER_CST + && ! tree_int_cst_lt (arg1, integer_one_node)) + { + switch (TREE_CODE (t)) + { + case GE_EXPR: + code = GT_EXPR; + TREE_SET_CODE (t, code); + arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0); + TREE_OPERAND (t, 1) = arg1; + break; + + case LT_EXPR: + code = LE_EXPR; + TREE_SET_CODE (t, code); + arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0); + TREE_OPERAND (t, 1) = arg1; + } + } + + /* If this is an EQ or NE comparison with zero and ARG0 is + (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require + two operations, but the latter can be done in one less insn + one machine that have only two-operand insns or on which a + constant cannot be the first operand. */ + if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR) + && TREE_CODE (arg0) == BIT_AND_EXPR) + { + if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR + && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0))) + return + fold (build (code, type, + build (BIT_AND_EXPR, TREE_TYPE (arg0), + build (RSHIFT_EXPR, + TREE_TYPE (TREE_OPERAND (arg0, 0)), + TREE_OPERAND (arg0, 1), + TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)), + convert (TREE_TYPE (arg0), + integer_one_node)), + arg1)); + else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR + && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0))) + return + fold (build (code, type, + build (BIT_AND_EXPR, TREE_TYPE (arg0), + build (RSHIFT_EXPR, + TREE_TYPE (TREE_OPERAND (arg0, 1)), + TREE_OPERAND (arg0, 0), + TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)), + convert (TREE_TYPE (arg0), + integer_one_node)), + arg1)); + } + + /* If this is an NE comparison of zero with an AND of one, remove the + comparison since the AND will give the correct value. */ + if (code == NE_EXPR && integer_zerop (arg1) + && TREE_CODE (arg0) == BIT_AND_EXPR + && integer_onep (TREE_OPERAND (arg0, 1))) + return convert (type, arg0); + + /* If we have (A & C) == C where C is a power of 2, convert this into + (A & C) != 0. Similarly for NE_EXPR. */ + if ((code == EQ_EXPR || code == NE_EXPR) + && TREE_CODE (arg0) == BIT_AND_EXPR + && integer_pow2p (TREE_OPERAND (arg0, 1)) + && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) + return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type, + arg0, integer_zero_node); + + /* Simplify comparison of something with itself. (For IEEE + floating-point, we can only do some of these simplifications.) */ + if (operand_equal_p (arg0, arg1, 0)) + { + switch (code) + { + case EQ_EXPR: + case GE_EXPR: + case LE_EXPR: + if (INTEGRAL_TYPE_P (TREE_TYPE (arg0))) + { + t = build_int_2 (1, 0); + TREE_TYPE (t) = type; + return t; + } + code = EQ_EXPR; + TREE_SET_CODE (t, code); + break; + + case NE_EXPR: + /* For NE, we can only do this simplification if integer. */ + if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))) + break; + /* ... fall through ... */ + case GT_EXPR: + case LT_EXPR: + t = build_int_2 (0, 0); + TREE_TYPE (t) = type; + return t; + } + } + + /* An unsigned comparison against 0 can be simplified. */ + if (integer_zerop (arg1) + && (INTEGRAL_TYPE_P (TREE_TYPE (arg1)) + || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE) + && TREE_UNSIGNED (TREE_TYPE (arg1))) + { + switch (TREE_CODE (t)) + { + case GT_EXPR: + code = NE_EXPR; + TREE_SET_CODE (t, NE_EXPR); + break; + case LE_EXPR: + code = EQ_EXPR; + TREE_SET_CODE (t, EQ_EXPR); + break; + case GE_EXPR: + return omit_one_operand (integer_type_node, + integer_one_node, arg0); + case LT_EXPR: + return omit_one_operand (integer_type_node, + integer_zero_node, arg0); + } + } + + /* If we are comparing an expression that just has comparisons + of two integer values, arithmetic expressions of those comparisons, + and constants, we can simplify it. There are only three cases + to check: the two values can either be equal, the first can be + greater, or the second can be greater. Fold the expression for + those three values. Since each value must be 0 or 1, we have + eight possibilities, each of which corresponds to the constant 0 + or 1 or one of the six possible comparisons. + + This handles common cases like (a > b) == 0 but also handles + expressions like ((x > y) - (y > x)) > 0, which supposedly + occur in macroized code. */ + + if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST) + { + tree cval1 = 0, cval2 = 0; + + if (twoval_comparison_p (arg0, &cval1, &cval2) + /* Don't handle degenerate cases here; they should already + have been handled anyway. */ + && cval1 != 0 && cval2 != 0 + && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2)) + && TREE_TYPE (cval1) == TREE_TYPE (cval2) + && INTEGRAL_TYPE_P (TREE_TYPE (cval1)) + && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)), + TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0)) + { + tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1)); + tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1)); + + /* We can't just pass T to eval_subst in case cval1 or cval2 + was the same as ARG1. */ + + tree high_result + = fold (build (code, type, + eval_subst (arg0, cval1, maxval, cval2, minval), + arg1)); + tree equal_result + = fold (build (code, type, + eval_subst (arg0, cval1, maxval, cval2, maxval), + arg1)); + tree low_result + = fold (build (code, type, + eval_subst (arg0, cval1, minval, cval2, maxval), + arg1)); + + /* All three of these results should be 0 or 1. Confirm they + are. Then use those values to select the proper code + to use. */ + + if ((integer_zerop (high_result) + || integer_onep (high_result)) + && (integer_zerop (equal_result) + || integer_onep (equal_result)) + && (integer_zerop (low_result) + || integer_onep (low_result))) + { + /* Make a 3-bit mask with the high-order bit being the + value for `>', the next for '=', and the low for '<'. */ + switch ((integer_onep (high_result) * 4) + + (integer_onep (equal_result) * 2) + + integer_onep (low_result)) + { + case 0: + /* Always false. */ + return omit_one_operand (type, integer_zero_node, arg0); + case 1: + code = LT_EXPR; + break; + case 2: + code = EQ_EXPR; + break; + case 3: + code = LE_EXPR; + break; + case 4: + code = GT_EXPR; + break; + case 5: + code = NE_EXPR; + break; + case 6: + code = GE_EXPR; + break; + case 7: + /* Always true. */ + return omit_one_operand (type, integer_one_node, arg0); + } + + return fold (build (code, type, cval1, cval2)); + } + } + } + + /* If this is a comparison of a field, we may be able to simplify it. */ + if ((TREE_CODE (arg0) == COMPONENT_REF + || TREE_CODE (arg0) == BIT_FIELD_REF) + && (code == EQ_EXPR || code == NE_EXPR) + /* Handle the constant case even without -O + to make sure the warnings are given. */ + && (optimize || TREE_CODE (arg1) == INTEGER_CST)) + { + t1 = optimize_bit_field_compare (code, type, arg0, arg1); + return t1 ? t1 : t; + } + + /* From here on, the only cases we handle are when the result is + known to be a constant. + + To compute GT, swap the arguments and do LT. + To compute GE, do LT and invert the result. + To compute LE, swap the arguments, do LT and invert the result. + To compute NE, do EQ and invert the result. + + Therefore, the code below must handle only EQ and LT. */ + + if (code == LE_EXPR || code == GT_EXPR) + { + tem = arg0, arg0 = arg1, arg1 = tem; + code = swap_tree_comparison (code); + } + + /* Note that it is safe to invert for real values here because we + will check below in the one case that it matters. */ + + invert = 0; + if (code == NE_EXPR || code == GE_EXPR) + { + invert = 1; + code = invert_tree_comparison (code); + } + + /* Compute a result for LT or EQ if args permit; + otherwise return T. */ + if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) + { + if (code == EQ_EXPR) + t1 = build_int_2 ((TREE_INT_CST_LOW (arg0) + == TREE_INT_CST_LOW (arg1)) + && (TREE_INT_CST_HIGH (arg0) + == TREE_INT_CST_HIGH (arg1)), + 0); + else + t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0)) + ? INT_CST_LT_UNSIGNED (arg0, arg1) + : INT_CST_LT (arg0, arg1)), + 0); + } + + /* Assume a nonexplicit constant cannot equal an explicit one, + since such code would be undefined anyway. + Exception: on sysvr4, using #pragma weak, + a label can come out as 0. */ + else if (TREE_CODE (arg1) == INTEGER_CST + && !integer_zerop (arg1) + && TREE_CONSTANT (arg0) + && TREE_CODE (arg0) == ADDR_EXPR + && code == EQ_EXPR) + t1 = build_int_2 (0, 0); + + /* Two real constants can be compared explicitly. */ + else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST) + { + /* If either operand is a NaN, the result is false with two + exceptions: First, an NE_EXPR is true on NaNs, but that case + is already handled correctly since we will be inverting the + result for NE_EXPR. Second, if we had inverted a LE_EXPR + or a GE_EXPR into a LT_EXPR, we must return true so that it + will be inverted into false. */ + + if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0)) + || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1))) + t1 = build_int_2 (invert && code == LT_EXPR, 0); + + else if (code == EQ_EXPR) + t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0), + TREE_REAL_CST (arg1)), + 0); + else + t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0), + TREE_REAL_CST (arg1)), + 0); + } + + if (t1 == NULL_TREE) + return t; + + if (invert) + TREE_INT_CST_LOW (t1) ^= 1; + + TREE_TYPE (t1) = type; + return t1; + + case COND_EXPR: + if (TREE_CODE (arg0) == INTEGER_CST) + return TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)); + else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0)) + return omit_one_operand (type, arg1, arg0); + + /* If the second operand is zero, invert the comparison and swap + the second and third operands. Likewise if the second operand + is constant and the third is not or if the third operand is + equivalent to the first operand of the comparison. */ + + if (integer_zerop (arg1) + || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2))) + || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<' + && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (t, 2), + TREE_OPERAND (arg0, 1)))) + { + /* See if this can be inverted. If it can't, possibly because + it was a floating-point inequality comparison, don't do + anything. */ + tem = invert_truthvalue (arg0); + + if (TREE_CODE (tem) != TRUTH_NOT_EXPR) + { + arg0 = TREE_OPERAND (t, 0) = tem; + TREE_OPERAND (t, 1) = TREE_OPERAND (t, 2); + TREE_OPERAND (t, 2) = arg1; + arg1 = TREE_OPERAND (t, 1); + } + } + + /* If we have A op B ? A : C, we may be able to convert this to a + simpler expression, depending on the operation and the values + of B and C. IEEE floating point prevents this though, + because A or B might be -0.0 or a NaN. */ + + if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<' + && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT + || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))) + && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), + arg1, TREE_OPERAND (arg0, 1))) + { + tree arg2 = TREE_OPERAND (t, 2); + enum tree_code comp_code = TREE_CODE (arg0); + + /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A), + depending on the comparison operation. */ + if (integer_zerop (TREE_OPERAND (arg0, 1)) + && TREE_CODE (arg2) == NEGATE_EXPR + && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0)) + switch (comp_code) + { + case EQ_EXPR: + return fold (build1 (NEGATE_EXPR, type, arg1)); + case NE_EXPR: + return convert (type, arg1); + case GE_EXPR: + case GT_EXPR: + return fold (build1 (ABS_EXPR, type, arg1)); + case LE_EXPR: + case LT_EXPR: + return fold (build1 (NEGATE_EXPR, type, + fold (build1 (ABS_EXPR, type, arg1)))); + } + + /* If this is A != 0 ? A : 0, this is simply A. For ==, it is + always zero. */ + + if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2)) + { + if (comp_code == NE_EXPR) + return convert (type, arg1); + else if (comp_code == EQ_EXPR) + return convert (type, integer_zero_node); + } + + /* If this is A op B ? A : B, this is either A, B, min (A, B), + or max (A, B), depending on the operation. */ + + if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1), + arg2, TREE_OPERAND (arg0, 0))) + switch (comp_code) + { + case EQ_EXPR: + return convert (type, arg2); + case NE_EXPR: + return convert (type, arg1); + case LE_EXPR: + case LT_EXPR: + return fold (build (MIN_EXPR, type, arg1, arg2)); + case GE_EXPR: + case GT_EXPR: + return fold (build (MAX_EXPR, type, arg1, arg2)); + } + + /* If this is A op C1 ? A : C2 with C1 and C2 constant integers, + we might still be able to simplify this. For example, + if C1 is one less or one more than C2, this might have started + out as a MIN or MAX and been transformed by this function. + Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */ + + if (INTEGRAL_TYPE_P (type) + && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST + && TREE_CODE (arg2) == INTEGER_CST) + switch (comp_code) + { + case EQ_EXPR: + /* We can replace A with C1 in this case. */ + arg1 = TREE_OPERAND (t, 1) + = convert (type, TREE_OPERAND (arg0, 1)); + break; + + case LT_EXPR: + /* If C1 is C2 + 1, this is min(A, C2). */ + if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1) + && operand_equal_p (TREE_OPERAND (arg0, 1), + const_binop (PLUS_EXPR, arg2, + integer_one_node, 0), 1)) + return fold (build (MIN_EXPR, type, arg1, arg2)); + break; + + case LE_EXPR: + /* If C1 is C2 - 1, this is min(A, C2). */ + if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1) + && operand_equal_p (TREE_OPERAND (arg0, 1), + const_binop (MINUS_EXPR, arg2, + integer_one_node, 0), 1)) + return fold (build (MIN_EXPR, type, arg1, arg2)); + break; + + case GT_EXPR: + /* If C1 is C2 - 1, this is max(A, C2). */ + if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1) + && operand_equal_p (TREE_OPERAND (arg0, 1), + const_binop (MINUS_EXPR, arg2, + integer_one_node, 0), 1)) + return fold (build (MAX_EXPR, type, arg1, arg2)); + break; + + case GE_EXPR: + /* If C1 is C2 + 1, this is max(A, C2). */ + if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1) + && operand_equal_p (TREE_OPERAND (arg0, 1), + const_binop (PLUS_EXPR, arg2, + integer_one_node, 0), 1)) + return fold (build (MAX_EXPR, type, arg1, arg2)); + break; + } + } + + /* Convert A ? 1 : 0 to simply A. */ + if (integer_onep (TREE_OPERAND (t, 1)) + && integer_zerop (TREE_OPERAND (t, 2)) + /* If we try to convert TREE_OPERAND (t, 0) to our type, the + call to fold will try to move the conversion inside + a COND, which will recurse. In that case, the COND_EXPR + is probably the best choice, so leave it alone. */ + && type == TREE_TYPE (arg0)) + return arg0; + + + /* Look for expressions of the form A & 2 ? 2 : 0. The result of this + operation is simply A & 2. */ + + if (integer_zerop (TREE_OPERAND (t, 2)) + && TREE_CODE (arg0) == NE_EXPR + && integer_zerop (TREE_OPERAND (arg0, 1)) + && integer_pow2p (arg1) + && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR + && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1), + arg1, 1)) + return convert (type, TREE_OPERAND (arg0, 0)); + + return t; + + case COMPOUND_EXPR: + /* When pedantic, a compound expression can be neither an lvalue + nor an integer constant expression. */ + if (TREE_SIDE_EFFECTS (arg0) || pedantic) + return t; + /* Don't let (0, 0) be null pointer constant. */ + if (integer_zerop (arg1)) + return non_lvalue (arg1); + return arg1; + + case COMPLEX_EXPR: + if (wins) + return build_complex (arg0, arg1); + return t; + + case REALPART_EXPR: + if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) + return t; + else if (TREE_CODE (arg0) == COMPLEX_EXPR) + return omit_one_operand (type, TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg0, 1)); + else if (TREE_CODE (arg0) == COMPLEX_CST) + return TREE_REALPART (arg0); + else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) + return fold (build (TREE_CODE (arg0), type, + fold (build1 (REALPART_EXPR, type, + TREE_OPERAND (arg0, 0))), + fold (build1 (REALPART_EXPR, + type, TREE_OPERAND (arg0, 1))))); + return t; + + case IMAGPART_EXPR: + if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) + return convert (type, integer_zero_node); + else if (TREE_CODE (arg0) == COMPLEX_EXPR) + return omit_one_operand (type, TREE_OPERAND (arg0, 1), + TREE_OPERAND (arg0, 0)); + else if (TREE_CODE (arg0) == COMPLEX_CST) + return TREE_IMAGPART (arg0); + else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) + return fold (build (TREE_CODE (arg0), type, + fold (build1 (IMAGPART_EXPR, type, + TREE_OPERAND (arg0, 0))), + fold (build1 (IMAGPART_EXPR, type, + TREE_OPERAND (arg0, 1))))); + return t; + + default: + return t; + } /* switch (code) */ +} |