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Fix a bug in InstCombine where we failed to preserve fast math flags when optimizing an FMUL expression.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199424 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2014-01-16 20:59:41 +00:00
parent 4b81ee4d9a
commit da5e148474
2 changed files with 7 additions and 5 deletions
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7
lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
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@ -525,8 +525,11 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
Value *N1 = dyn_castFNegVal(Opnd1, IgnoreZeroSign);
// -X * -Y => X*Y
if (N1)
return BinaryOperator::CreateFMul(N0, N1);
if (N1) {
Value *FMul = Builder->CreateFMul(N0, N1);
FMul->takeName(&I);
return ReplaceInstUsesWith(I, FMul);
}
if (Opnd0->hasOneUse()) {
// -X * Y => -(X*Y) (Promote negation as high as possible)

5
test/Transforms/InstCombine/fmul.ll
View File

@ -24,10 +24,10 @@ define float @test2(float %x) {
define float @test3(float %x, float %y) {
%sub1 = fsub float -0.000000e+00, %x
%sub2 = fsub float -0.000000e+00, %y
%mul = fmul float %sub1, %sub2
%mul = fmul fast float %sub1, %sub2
ret float %mul
; CHECK-LABEL: @test3(
; CHECK: fmul float %x, %y
; CHECK: fmul fast float %x, %y
}
; (0.0 - X) * (0.0 - Y) => X * Y
@ -104,4 +104,3 @@ define float @test9(float %x) {
; CHECK: fsub
}