From 3190427825181d1663bb49f7c4074901a0a22987 Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Wed, 28 Feb 2018 22:30:04 +0000
Subject: [PATCH] [InstCombine] simplify code for X * -1.0 --> -X; NFC

I've added random FMF to one of the tests to show those are propagated.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326377 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 10 +++-------
 test/Transforms/InstCombine/fmul.ll                 |  4 ++--
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index f79e33fe597..b445c33e88c 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -563,13 +563,9 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
     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/test/Transforms/InstCombine/fmul.ll b/test/Transforms/InstCombine/fmul.ll
index 2eaa7c3e761..34e0047946c 100644
--- a/test/Transforms/InstCombine/fmul.ll
+++ b/test/Transforms/InstCombine/fmul.ll
@@ -153,10 +153,10 @@ define float @test9(float %x) {
 ; 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
 }