commit 8b23b2bbd9622c5f079a71c7078d167052f6a70c
author Craig Topper <craig.topper@intel.com> Mon Dec 30 13:24:08 2019 -0800
committer Craig Topper <craig.topper@intel.com> Mon Dec 30 13:24:11 2019 -0800
tree b57c221f85f31a6f8bbe64e5ff5892ac48a85ab4
parent 07be32961a694670885626e72faca6f0007f14c9

[CodeGen] Use CreateFNeg in buildFMulAdd

We have an fneg instruction now and should use it instead of the fsub -0.0 idiom. Looks like we had no test that showed that we handled the negation cases here so I've added new tests.

Differential Revision: https://reviews.llvm.org/D72010

clang/lib/CodeGen/CGExprScalar.cpp

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index b884616..12bf37e 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -3345,17 +3345,10 @@
 
   Value *MulOp0 = MulOp->getOperand(0);
   Value *MulOp1 = MulOp->getOperand(1);
-  if (negMul) {
-    MulOp0 =
-      Builder.CreateFSub(
-        llvm::ConstantFP::getZeroValueForNegation(MulOp0->getType()), MulOp0,
-        "neg");
-  } else if (negAdd) {
-    Addend =
-      Builder.CreateFSub(
-        llvm::ConstantFP::getZeroValueForNegation(Addend->getType()), Addend,
-        "neg");
-  }
+  if (negMul)
+    MulOp0 = Builder.CreateFNeg(MulOp0, "neg");
+  if (negAdd)
+    Addend = Builder.CreateFNeg(Addend, "neg");
 
   Value *FMulAdd = Builder.CreateCall(
       CGF.CGM.getIntrinsic(llvm::Intrinsic::fmuladd, Addend->getType()),