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[GVN] Respect fast-math-flags on fcmps 

We assumed that flags were only present on binary operators.  This is
not true, they may also be present on calls and fcmps.

llvm-svn: 267113
This commit is contained in:
David Majnemer 2016-04-22 06:37:51 +00:00
parent 68318e0414
commit d0ce8f1485
3 changed files with 56 additions and 30 deletions
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29
llvm/lib/IR/Instruction.cpp
View File

@ -217,32 +217,41 @@ void Instruction::copyFastMathFlags(const Instruction *I) {
void Instruction::copyIRFlags(const Value *V) {
// Copy the wrapping flags.
if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
setHasNoSignedWrap(OB->hasNoSignedWrap());
setHasNoUnsignedWrap(OB->hasNoUnsignedWrap());
if (isa<OverflowingBinaryOperator>(this)) {
setHasNoSignedWrap(OB->hasNoSignedWrap());
setHasNoUnsignedWrap(OB->hasNoUnsignedWrap());
}
}
// Copy the exact flag.
if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
setIsExact(PE->isExact());
if (isa<PossiblyExactOperator>(this))
setIsExact(PE->isExact());
// Copy the fast-math flags.
if (auto *FP = dyn_cast<FPMathOperator>(V))
copyFastMathFlags(FP->getFastMathFlags());
if (isa<FPMathOperator>(this))
copyFastMathFlags(FP->getFastMathFlags());
}
void Instruction::andIRFlags(const Value *V) {
if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
setHasNoSignedWrap(hasNoSignedWrap() & OB->hasNoSignedWrap());
setHasNoUnsignedWrap(hasNoUnsignedWrap() & OB->hasNoUnsignedWrap());
if (isa<OverflowingBinaryOperator>(this)) {
setHasNoSignedWrap(hasNoSignedWrap() & OB->hasNoSignedWrap());
setHasNoUnsignedWrap(hasNoUnsignedWrap() & OB->hasNoUnsignedWrap());
}
}
if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
setIsExact(isExact() & PE->isExact());
if (isa<PossiblyExactOperator>(this))
setIsExact(isExact() & PE->isExact());
if (auto *FP = dyn_cast<FPMathOperator>(V)) {
FastMathFlags FM = getFastMathFlags();
FM &= FP->getFastMathFlags();
copyFastMathFlags(FM);
if (isa<FPMathOperator>(this)) {
FastMathFlags FM = getFastMathFlags();
FM &= FP->getFastMathFlags();
copyFastMathFlags(FM);
}
}
}

39
llvm/lib/Transforms/Scalar/GVN.cpp
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@ -1725,30 +1725,29 @@ bool GVN::processAssumeIntrinsic(IntrinsicInst *IntrinsicI) {
}
static void patchReplacementInstruction(Instruction *I, Value *Repl) {
auto *ReplInst = dyn_cast<Instruction>(Repl);
if (!ReplInst)
return;
// Patch the replacement so that it is not more restrictive than the value
// being replaced.
BinaryOperator *Op = dyn_cast<BinaryOperator>(I);
BinaryOperator *ReplOp = dyn_cast<BinaryOperator>(Repl);
if (Op && ReplOp)
ReplOp->andIRFlags(Op);
ReplInst->andIRFlags(I);
if (Instruction *ReplInst = dyn_cast<Instruction>(Repl)) {
// FIXME: If both the original and replacement value are part of the
// same control-flow region (meaning that the execution of one
// guarantees the execution of the other), then we can combine the
// noalias scopes here and do better than the general conservative
// answer used in combineMetadata().
// FIXME: If both the original and replacement value are part of the
// same control-flow region (meaning that the execution of one
// guarantees the execution of the other), then we can combine the
// noalias scopes here and do better than the general conservative
// answer used in combineMetadata().
// In general, GVN unifies expressions over different control-flow
// regions, and so we need a conservative combination of the noalias
// scopes.
static const unsigned KnownIDs[] = {
LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
LLVMContext::MD_noalias, LLVMContext::MD_range,
LLVMContext::MD_fpmath, LLVMContext::MD_invariant_load,
LLVMContext::MD_invariant_group};
combineMetadata(ReplInst, I, KnownIDs);
}
// In general, GVN unifies expressions over different control-flow
// regions, and so we need a conservative combination of the noalias
// scopes.
static const unsigned KnownIDs[] = {
LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
LLVMContext::MD_noalias, LLVMContext::MD_range,
LLVMContext::MD_fpmath, LLVMContext::MD_invariant_load,
LLVMContext::MD_invariant_group};
combineMetadata(ReplInst, I, KnownIDs);
}
static void patchAndReplaceAllUsesWith(Instruction *I, Value *Repl) {

18
llvm/test/Transforms/GVN/flags.ll Normal file
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@ -0,0 +1,18 @@
; RUN: opt -gvn -S < %s | FileCheck %s
declare void @use(i1)
define void @test1(float %x, float %y) {
entry:
%cmp1 = fcmp nnan oeq float %y, %x
%cmp2 = fcmp oeq float %x, %y
call void @use(i1 %cmp1)
call void @use(i1 %cmp2)
ret void
}
; CHECK-LABEL: define void @test1(
; CHECK: %[[cmp:.*]] = fcmp oeq float %y, %x
; CHECK-NEXT: call void @use(i1 %[[cmp]])
; CHECK-NEXT: call void @use(i1 %[[cmp]])
; CHECK-NEXT: ret void