aboutsummaryrefslogtreecommitdiff
path: root/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineAndOrXor.cpp')
-rw-r--r--lib/Transforms/InstCombine/InstCombineAndOrXor.cpp243
1 files changed, 106 insertions, 137 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 5e0bfe8e26d2..0dbe11d2f01f 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -14,6 +14,7 @@
#include "InstCombine.h"
#include "llvm/Intrinsics.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/PatternMatch.h"
using namespace llvm;
@@ -62,50 +63,6 @@ static inline Value *dyn_castNotVal(Value *V) {
return 0;
}
-
-/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits
-/// are carefully arranged to allow folding of expressions such as:
-///
-/// (A < B) | (A > B) --> (A != B)
-///
-/// Note that this is only valid if the first and second predicates have the
-/// same sign. Is illegal to do: (A u< B) | (A s> B)
-///
-/// Three bits are used to represent the condition, as follows:
-/// 0 A > B
-/// 1 A == B
-/// 2 A < B
-///
-/// <=> Value Definition
-/// 000 0 Always false
-/// 001 1 A > B
-/// 010 2 A == B
-/// 011 3 A >= B
-/// 100 4 A < B
-/// 101 5 A != B
-/// 110 6 A <= B
-/// 111 7 Always true
-///
-static unsigned getICmpCode(const ICmpInst *ICI) {
- switch (ICI->getPredicate()) {
- // False -> 0
- case ICmpInst::ICMP_UGT: return 1; // 001
- case ICmpInst::ICMP_SGT: return 1; // 001
- case ICmpInst::ICMP_EQ: return 2; // 010
- case ICmpInst::ICMP_UGE: return 3; // 011
- case ICmpInst::ICMP_SGE: return 3; // 011
- case ICmpInst::ICMP_ULT: return 4; // 100
- case ICmpInst::ICMP_SLT: return 4; // 100
- case ICmpInst::ICMP_NE: return 5; // 101
- case ICmpInst::ICMP_ULE: return 6; // 110
- case ICmpInst::ICMP_SLE: return 6; // 110
- // True -> 7
- default:
- llvm_unreachable("Invalid ICmp predicate!");
- return 0;
- }
-}
-
/// getFCmpCode - Similar to getICmpCode but for FCmpInst. This encodes a fcmp
/// predicate into a three bit mask. It also returns whether it is an ordered
/// predicate by reference.
@@ -130,31 +87,19 @@ static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
default:
// Not expecting FCMP_FALSE and FCMP_TRUE;
llvm_unreachable("Unexpected FCmp predicate!");
- return 0;
}
}
-/// getICmpValue - This is the complement of getICmpCode, which turns an
+/// getNewICmpValue - This is the complement of getICmpCode, which turns an
/// opcode and two operands into either a constant true or false, or a brand
/// new ICmp instruction. The sign is passed in to determine which kind
/// of predicate to use in the new icmp instruction.
-static Value *getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
- InstCombiner::BuilderTy *Builder) {
- CmpInst::Predicate Pred;
- switch (Code) {
- default: assert(0 && "Illegal ICmp code!");
- case 0: // False.
- return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
- case 1: Pred = Sign ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; break;
- case 2: Pred = ICmpInst::ICMP_EQ; break;
- case 3: Pred = Sign ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; break;
- case 4: Pred = Sign ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT; break;
- case 5: Pred = ICmpInst::ICMP_NE; break;
- case 6: Pred = Sign ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; break;
- case 7: // True.
- return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
- }
- return Builder->CreateICmp(Pred, LHS, RHS);
+static Value *getNewICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
+ InstCombiner::BuilderTy *Builder) {
+ ICmpInst::Predicate NewPred;
+ if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred))
+ return NewConstant;
+ return Builder->CreateICmp(NewPred, LHS, RHS);
}
/// getFCmpValue - This is the complement of getFCmpCode, which turns an
@@ -165,7 +110,7 @@ static Value *getFCmpValue(bool isordered, unsigned code,
InstCombiner::BuilderTy *Builder) {
CmpInst::Predicate Pred;
switch (code) {
- default: assert(0 && "Illegal FCmp code!");
+ default: llvm_unreachable("Illegal FCmp code!");
case 0: Pred = isordered ? FCmpInst::FCMP_ORD : FCmpInst::FCMP_UNO; break;
case 1: Pred = isordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT; break;
case 2: Pred = isordered ? FCmpInst::FCMP_OEQ : FCmpInst::FCMP_UEQ; break;
@@ -180,14 +125,6 @@ static Value *getFCmpValue(bool isordered, unsigned code,
return Builder->CreateFCmp(Pred, LHS, RHS);
}
-/// PredicatesFoldable - Return true if both predicates match sign or if at
-/// least one of them is an equality comparison (which is signless).
-static bool PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) {
- return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) ||
- (CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) ||
- (CmpInst::isSigned(p2) && ICmpInst::isEquality(p1));
-}
-
// OptAndOp - This handles expressions of the form ((val OP C1) & C2). Where
// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is
// guaranteed to be a binary operator.
@@ -558,6 +495,38 @@ static unsigned getTypeOfMaskedICmp(Value* A, Value* B, Value* C,
return result;
}
+/// decomposeBitTestICmp - Decompose an icmp into the form ((X & Y) pred Z)
+/// if possible. The returned predicate is either == or !=. Returns false if
+/// decomposition fails.
+static bool decomposeBitTestICmp(const ICmpInst *I, ICmpInst::Predicate &Pred,
+ Value *&X, Value *&Y, Value *&Z) {
+ // X < 0 is equivalent to (X & SignBit) != 0.
+ if (I->getPredicate() == ICmpInst::ICMP_SLT)
+ if (ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
+ if (C->isZero()) {
+ X = I->getOperand(0);
+ Y = ConstantInt::get(I->getContext(),
+ APInt::getSignBit(C->getBitWidth()));
+ Pred = ICmpInst::ICMP_NE;
+ Z = C;
+ return true;
+ }
+
+ // X > -1 is equivalent to (X & SignBit) == 0.
+ if (I->getPredicate() == ICmpInst::ICMP_SGT)
+ if (ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
+ if (C->isAllOnesValue()) {
+ X = I->getOperand(0);
+ Y = ConstantInt::get(I->getContext(),
+ APInt::getSignBit(C->getBitWidth()));
+ Pred = ICmpInst::ICMP_EQ;
+ Z = ConstantInt::getNullValue(C->getType());
+ return true;
+ }
+
+ return false;
+}
+
/// foldLogOpOfMaskedICmpsHelper:
/// handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
/// return the set of pattern classes (from MaskedICmpType)
@@ -565,10 +534,9 @@ static unsigned getTypeOfMaskedICmp(Value* A, Value* B, Value* C,
static unsigned foldLogOpOfMaskedICmpsHelper(Value*& A,
Value*& B, Value*& C,
Value*& D, Value*& E,
- ICmpInst *LHS, ICmpInst *RHS) {
- ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
- if (LHSCC != ICmpInst::ICMP_EQ && LHSCC != ICmpInst::ICMP_NE) return 0;
- if (RHSCC != ICmpInst::ICMP_EQ && RHSCC != ICmpInst::ICMP_NE) return 0;
+ ICmpInst *LHS, ICmpInst *RHS,
+ ICmpInst::Predicate &LHSCC,
+ ICmpInst::Predicate &RHSCC) {
if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType()) return 0;
// vectors are not (yet?) supported
if (LHS->getOperand(0)->getType()->isVectorTy()) return 0;
@@ -582,40 +550,60 @@ static unsigned foldLogOpOfMaskedICmpsHelper(Value*& A,
Value *L1 = LHS->getOperand(0);
Value *L2 = LHS->getOperand(1);
Value *L11,*L12,*L21,*L22;
- if (match(L1, m_And(m_Value(L11), m_Value(L12)))) {
- if (!match(L2, m_And(m_Value(L21), m_Value(L22))))
+ // Check whether the icmp can be decomposed into a bit test.
+ if (decomposeBitTestICmp(LHS, LHSCC, L11, L12, L2)) {
+ L21 = L22 = L1 = 0;
+ } else {
+ // Look for ANDs in the LHS icmp.
+ if (match(L1, m_And(m_Value(L11), m_Value(L12)))) {
+ if (!match(L2, m_And(m_Value(L21), m_Value(L22))))
+ L21 = L22 = 0;
+ } else {
+ if (!match(L2, m_And(m_Value(L11), m_Value(L12))))
+ return 0;
+ std::swap(L1, L2);
L21 = L22 = 0;
- }
- else {
- if (!match(L2, m_And(m_Value(L11), m_Value(L12))))
- return 0;
- std::swap(L1, L2);
- L21 = L22 = 0;
+ }
}
+ // Bail if LHS was a icmp that can't be decomposed into an equality.
+ if (!ICmpInst::isEquality(LHSCC))
+ return 0;
+
Value *R1 = RHS->getOperand(0);
Value *R2 = RHS->getOperand(1);
Value *R11,*R12;
bool ok = false;
- if (match(R1, m_And(m_Value(R11), m_Value(R12)))) {
- if (R11 != 0 && (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22)) {
- A = R11; D = R12; E = R2; ok = true;
+ if (decomposeBitTestICmp(RHS, RHSCC, R11, R12, R2)) {
+ if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
+ A = R11; D = R12;
+ } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
+ A = R12; D = R11;
+ } else {
+ return 0;
}
- else
- if (R12 != 0 && (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22)) {
+ E = R2; R1 = 0; ok = true;
+ } else if (match(R1, m_And(m_Value(R11), m_Value(R12)))) {
+ if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
+ A = R11; D = R12; E = R2; ok = true;
+ } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
A = R12; D = R11; E = R2; ok = true;
}
}
+
+ // Bail if RHS was a icmp that can't be decomposed into an equality.
+ if (!ICmpInst::isEquality(RHSCC))
+ return 0;
+
+ // Look for ANDs in on the right side of the RHS icmp.
if (!ok && match(R2, m_And(m_Value(R11), m_Value(R12)))) {
- if (R11 != 0 && (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22)) {
- A = R11; D = R12; E = R1; ok = true;
- }
- else
- if (R12 != 0 && (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22)) {
+ if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
+ A = R11; D = R12; E = R1; ok = true;
+ } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
A = R12; D = R11; E = R1; ok = true;
- }
- else
+ } else {
return 0;
+ }
}
if (!ok)
return 0;
@@ -644,8 +632,12 @@ static Value* foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS,
ICmpInst::Predicate NEWCC,
llvm::InstCombiner::BuilderTy* Builder) {
Value *A = 0, *B = 0, *C = 0, *D = 0, *E = 0;
- unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS);
+ ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
+ unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS,
+ LHSCC, RHSCC);
if (mask == 0) return 0;
+ assert(ICmpInst::isEquality(LHSCC) && ICmpInst::isEquality(RHSCC) &&
+ "foldLogOpOfMaskedICmpsHelper must return an equality predicate.");
if (NEWCC == ICmpInst::ICMP_NE)
mask >>= 1; // treat "Not"-states as normal states
@@ -693,11 +685,11 @@ static Value* foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS,
ConstantInt *CCst = dyn_cast<ConstantInt>(C);
if (CCst == 0) return 0;
- if (LHS->getPredicate() != NEWCC)
+ if (LHSCC != NEWCC)
CCst = dyn_cast<ConstantInt>( ConstantExpr::getXor(BCst, CCst) );
ConstantInt *ECst = dyn_cast<ConstantInt>(E);
if (ECst == 0) return 0;
- if (RHS->getPredicate() != NEWCC)
+ if (RHSCC != NEWCC)
ECst = dyn_cast<ConstantInt>( ConstantExpr::getXor(DCst, ECst) );
ConstantInt* MCst = dyn_cast<ConstantInt>(
ConstantExpr::getAnd(ConstantExpr::getAnd(BCst, DCst),
@@ -728,7 +720,7 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
unsigned Code = getICmpCode(LHS) & getICmpCode(RHS);
bool isSigned = LHS->isSigned() || RHS->isSigned();
- return getICmpValue(isSigned, Code, Op0, Op1, Builder);
+ return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
}
}
@@ -756,24 +748,12 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
Value *NewOr = Builder->CreateOr(Val, Val2);
return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
}
-
- // (icmp slt A, 0) & (icmp slt B, 0) --> (icmp slt (A&B), 0)
- if (LHSCC == ICmpInst::ICMP_SLT && LHSCst->isZero()) {
- Value *NewAnd = Builder->CreateAnd(Val, Val2);
- return Builder->CreateICmp(LHSCC, NewAnd, LHSCst);
- }
-
- // (icmp sgt A, -1) & (icmp sgt B, -1) --> (icmp sgt (A|B), -1)
- if (LHSCC == ICmpInst::ICMP_SGT && LHSCst->isAllOnesValue()) {
- Value *NewOr = Builder->CreateOr(Val, Val2);
- return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
- }
}
// (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
// where CMAX is the all ones value for the truncated type,
// iff the lower bits of C2 and CA are zero.
- if (LHSCC == RHSCC && ICmpInst::isEquality(LHSCC) &&
+ if (LHSCC == ICmpInst::ICMP_EQ && LHSCC == RHSCC &&
LHS->hasOneUse() && RHS->hasOneUse()) {
Value *V;
ConstantInt *AndCst, *SmallCst = 0, *BigCst = 0;
@@ -805,7 +785,7 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
}
}
}
-
+
// From here on, we only handle:
// (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
if (Val != Val2) return 0;
@@ -1382,13 +1362,8 @@ static bool CollectBSwapParts(Value *V, int OverallLeftShift, uint32_t ByteMask,
// part of the value (e.g. byte 3) then it must be shifted right. If from the
// low part, it must be shifted left.
unsigned DestByteNo = InputByteNo + OverallLeftShift;
- if (InputByteNo < ByteValues.size()/2) {
- if (ByteValues.size()-1-DestByteNo != InputByteNo)
- return true;
- } else {
- if (ByteValues.size()-1-DestByteNo != InputByteNo)
- return true;
- }
+ if (ByteValues.size()-1-DestByteNo != InputByteNo)
+ return true;
// If the destination byte value is already defined, the values are or'd
// together, which isn't a bswap (unless it's an or of the same bits).
@@ -1469,7 +1444,7 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
unsigned Code = getICmpCode(LHS) | getICmpCode(RHS);
bool isSigned = LHS->isSigned() || RHS->isSigned();
- return getICmpValue(isSigned, Code, Op0, Op1, Builder);
+ return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
}
}
@@ -1490,18 +1465,6 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
Value *NewOr = Builder->CreateOr(Val, Val2);
return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
}
-
- // (icmp slt A, 0) | (icmp slt B, 0) --> (icmp slt (A|B), 0)
- if (LHSCC == ICmpInst::ICMP_SLT && LHSCst->isZero()) {
- Value *NewOr = Builder->CreateOr(Val, Val2);
- return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
- }
-
- // (icmp sgt A, -1) | (icmp sgt B, -1) --> (icmp sgt (A&B), -1)
- if (LHSCC == ICmpInst::ICMP_SGT && LHSCst->isAllOnesValue()) {
- Value *NewAnd = Builder->CreateAnd(Val, Val2);
- return Builder->CreateICmp(LHSCC, NewAnd, LHSCst);
- }
}
// (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
@@ -1586,7 +1549,6 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
case ICmpInst::ICMP_SLT: // (X != 13 | X s< 15) -> true
return ConstantInt::getTrue(LHS->getContext());
}
- break;
case ICmpInst::ICMP_ULT:
switch (RHSCC) {
default: llvm_unreachable("Unknown integer condition code!");
@@ -1962,8 +1924,11 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
}
// Canonicalize xor to the RHS.
- if (match(Op0, m_Xor(m_Value(), m_Value())))
+ bool SwappedForXor = false;
+ if (match(Op0, m_Xor(m_Value(), m_Value()))) {
std::swap(Op0, Op1);
+ SwappedForXor = true;
+ }
// A | ( A ^ B) -> A | B
// A | (~A ^ B) -> A | ~B
@@ -1994,6 +1959,9 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
return BinaryOperator::CreateOr(Not, Op0);
}
+ if (SwappedForXor)
+ std::swap(Op0, Op1);
+
if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
if (Value *Res = FoldOrOfICmps(LHS, RHS))
@@ -2281,7 +2249,8 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS);
bool isSigned = LHS->isSigned() || RHS->isSigned();
return ReplaceInstUsesWith(I,
- getICmpValue(isSigned, Code, Op0, Op1, Builder));
+ getNewICmpValue(isSigned, Code, Op0, Op1,
+ Builder));
}
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-21 21:48:47 +0000