[InstCombine] simplify code for X * -1.0 --> -X; NFC
I've added random FMF to one of the tests to show those are propagated.
llvm-svn: 326377
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index f79e33f..b445c33 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -563,13 +563,9 @@
if (match(Op0, m_FNeg(m_Value(X))))
return BinaryOperator::CreateFMulFMF(X, ConstantExpr::getFNeg(C), &I);
- // (fmul X, -1.0) --> (fsub -0.0, X)
- if (match(C, m_SpecificFP(-1.0))) {
- Constant *NegZero = ConstantFP::getNegativeZero(Op1->getType());
- Instruction *RI = BinaryOperator::CreateFSub(NegZero, Op0);
- RI->copyFastMathFlags(&I);
- return RI;
- }
+ // X * -1.0 --> -X
+ if (match(C, m_SpecificFP(-1.0)))
+ return BinaryOperator::CreateFNegFMF(Op0, &I);
if (AllowReassociate && C->isFiniteNonZeroFP()) {
// Let MDC denote an expression in one of these forms:
diff --git a/llvm/test/Transforms/InstCombine/fmul.ll b/llvm/test/Transforms/InstCombine/fmul.ll
index 2eaa7c3..34e0047 100644
--- a/llvm/test/Transforms/InstCombine/fmul.ll
+++ b/llvm/test/Transforms/InstCombine/fmul.ll
@@ -153,10 +153,10 @@
; PR18532
define <4 x float> @test10(<4 x float> %x) {
; CHECK-LABEL: @test10(
-; CHECK-NEXT: [[MUL:%.*]] = fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, [[X:%.*]]
+; CHECK-NEXT: [[MUL:%.*]] = fsub arcp afn <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, [[X:%.*]]
; CHECK-NEXT: ret <4 x float> [[MUL]]
;
- %mul = fmul <4 x float> %x, <float -1.0, float -1.0, float -1.0, float -1.0>
+ %mul = fmul arcp afn <4 x float> %x, <float -1.0, float -1.0, float -1.0, float -1.0>
ret <4 x float> %mul
}