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-rw-r--r--lib/Transforms/InstCombine/InstCombineCompares.cpp128
1 files changed, 81 insertions, 47 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 60ed4057cedd..6492eaedae9c 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -3506,7 +3506,7 @@ bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
// We can strength reduce this signed add into a regular add if we can prove
// that it will never overflow.
if (OCF == OCF_SIGNED_ADD)
- if (WillNotOverflowSignedAdd(LHS, RHS, OrigI))
+ if (willNotOverflowSignedAdd(LHS, RHS, OrigI))
return SetResult(Builder->CreateNSWAdd(LHS, RHS), Builder->getFalse(),
true);
break;
@@ -3519,11 +3519,11 @@ bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
return SetResult(LHS, Builder->getFalse(), false);
if (OCF == OCF_SIGNED_SUB) {
- if (WillNotOverflowSignedSub(LHS, RHS, OrigI))
+ if (willNotOverflowSignedSub(LHS, RHS, OrigI))
return SetResult(Builder->CreateNSWSub(LHS, RHS), Builder->getFalse(),
true);
} else {
- if (WillNotOverflowUnsignedSub(LHS, RHS, OrigI))
+ if (willNotOverflowUnsignedSub(LHS, RHS, OrigI))
return SetResult(Builder->CreateNUWSub(LHS, RHS), Builder->getFalse(),
true);
}
@@ -3553,7 +3553,7 @@ bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
return SetResult(LHS, Builder->getFalse(), false);
if (OCF == OCF_SIGNED_MUL)
- if (WillNotOverflowSignedMul(LHS, RHS, OrigI))
+ if (willNotOverflowSignedMul(LHS, RHS, OrigI))
return SetResult(Builder->CreateNSWMul(LHS, RHS), Builder->getFalse(),
true);
break;
@@ -4260,6 +4260,80 @@ static ICmpInst *canonicalizeCmpWithConstant(ICmpInst &I) {
return new ICmpInst(NewPred, Op0, ConstantExpr::getAdd(Op1C, OneOrNegOne));
}
+/// Integer compare with boolean values can always be turned into bitwise ops.
+static Instruction *canonicalizeICmpBool(ICmpInst &I,
+ InstCombiner::BuilderTy &Builder) {
+ Value *A = I.getOperand(0), *B = I.getOperand(1);
+ assert(A->getType()->getScalarType()->isIntegerTy(1) && "Bools only");
+
+ // A boolean compared to true/false can be simplified to Op0/true/false in
+ // 14 out of the 20 (10 predicates * 2 constants) possible combinations.
+ // Cases not handled by InstSimplify are always 'not' of Op0.
+ if (match(B, m_Zero())) {
+ switch (I.getPredicate()) {
+ case CmpInst::ICMP_EQ: // A == 0 -> !A
+ case CmpInst::ICMP_ULE: // A <=u 0 -> !A
+ case CmpInst::ICMP_SGE: // A >=s 0 -> !A
+ return BinaryOperator::CreateNot(A);
+ default:
+ llvm_unreachable("ICmp i1 X, C not simplified as expected.");
+ }
+ } else if (match(B, m_One())) {
+ switch (I.getPredicate()) {
+ case CmpInst::ICMP_NE: // A != 1 -> !A
+ case CmpInst::ICMP_ULT: // A <u 1 -> !A
+ case CmpInst::ICMP_SGT: // A >s -1 -> !A
+ return BinaryOperator::CreateNot(A);
+ default:
+ llvm_unreachable("ICmp i1 X, C not simplified as expected.");
+ }
+ }
+
+ switch (I.getPredicate()) {
+ default:
+ llvm_unreachable("Invalid icmp instruction!");
+ case ICmpInst::ICMP_EQ:
+ // icmp eq i1 A, B -> ~(A ^ B)
+ return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
+
+ case ICmpInst::ICMP_NE:
+ // icmp ne i1 A, B -> A ^ B
+ return BinaryOperator::CreateXor(A, B);
+
+ case ICmpInst::ICMP_UGT:
+ // icmp ugt -> icmp ult
+ std::swap(A, B);
+ LLVM_FALLTHROUGH;
+ case ICmpInst::ICMP_ULT:
+ // icmp ult i1 A, B -> ~A & B
+ return BinaryOperator::CreateAnd(Builder.CreateNot(A), B);
+
+ case ICmpInst::ICMP_SGT:
+ // icmp sgt -> icmp slt
+ std::swap(A, B);
+ LLVM_FALLTHROUGH;
+ case ICmpInst::ICMP_SLT:
+ // icmp slt i1 A, B -> A & ~B
+ return BinaryOperator::CreateAnd(Builder.CreateNot(B), A);
+
+ case ICmpInst::ICMP_UGE:
+ // icmp uge -> icmp ule
+ std::swap(A, B);
+ LLVM_FALLTHROUGH;
+ case ICmpInst::ICMP_ULE:
+ // icmp ule i1 A, B -> ~A | B
+ return BinaryOperator::CreateOr(Builder.CreateNot(A), B);
+
+ case ICmpInst::ICMP_SGE:
+ // icmp sge -> icmp sle
+ std::swap(A, B);
+ LLVM_FALLTHROUGH;
+ case ICmpInst::ICMP_SLE:
+ // icmp sle i1 A, B -> A | ~B
+ return BinaryOperator::CreateOr(Builder.CreateNot(B), A);
+ }
+}
+
Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
bool Changed = false;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
@@ -4297,49 +4371,9 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
}
}
- Type *Ty = Op0->getType();
-
- // icmp's with boolean values can always be turned into bitwise operations
- if (Ty->getScalarType()->isIntegerTy(1)) {
- switch (I.getPredicate()) {
- default: llvm_unreachable("Invalid icmp instruction!");
- case ICmpInst::ICMP_EQ: { // icmp eq i1 A, B -> ~(A^B)
- Value *Xor = Builder->CreateXor(Op0, Op1, I.getName() + "tmp");
- return BinaryOperator::CreateNot(Xor);
- }
- case ICmpInst::ICMP_NE: // icmp ne i1 A, B -> A^B
- return BinaryOperator::CreateXor(Op0, Op1);
-
- case ICmpInst::ICMP_UGT:
- std::swap(Op0, Op1); // Change icmp ugt -> icmp ult
- LLVM_FALLTHROUGH;
- case ICmpInst::ICMP_ULT:{ // icmp ult i1 A, B -> ~A & B
- Value *Not = Builder->CreateNot(Op0, I.getName() + "tmp");
- return BinaryOperator::CreateAnd(Not, Op1);
- }
- case ICmpInst::ICMP_SGT:
- std::swap(Op0, Op1); // Change icmp sgt -> icmp slt
- LLVM_FALLTHROUGH;
- case ICmpInst::ICMP_SLT: { // icmp slt i1 A, B -> A & ~B
- Value *Not = Builder->CreateNot(Op1, I.getName() + "tmp");
- return BinaryOperator::CreateAnd(Not, Op0);
- }
- case ICmpInst::ICMP_UGE:
- std::swap(Op0, Op1); // Change icmp uge -> icmp ule
- LLVM_FALLTHROUGH;
- case ICmpInst::ICMP_ULE: { // icmp ule i1 A, B -> ~A | B
- Value *Not = Builder->CreateNot(Op0, I.getName() + "tmp");
- return BinaryOperator::CreateOr(Not, Op1);
- }
- case ICmpInst::ICMP_SGE:
- std::swap(Op0, Op1); // Change icmp sge -> icmp sle
- LLVM_FALLTHROUGH;
- case ICmpInst::ICMP_SLE: { // icmp sle i1 A, B -> A | ~B
- Value *Not = Builder->CreateNot(Op1, I.getName() + "tmp");
- return BinaryOperator::CreateOr(Not, Op0);
- }
- }
- }
+ if (Op0->getType()->getScalarType()->isIntegerTy(1))
+ if (Instruction *Res = canonicalizeICmpBool(I, *Builder))
+ return Res;
if (ICmpInst *NewICmp = canonicalizeCmpWithConstant(I))
return NewICmp;
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-04 20:17:04 +0000