Fix two cases where we could lose fast math flags when optimizing FADD expressions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199427 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 4 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 534feb8fad..d49153e482 100644
--- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1198,13 +1198,19 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
 
   // -A + B  -->  B - A
   // -A + -B  -->  -(A + B)
-  if (Value *LHSV = dyn_castFNegVal(LHS))
-    return BinaryOperator::CreateFSub(RHS, LHSV);
+  if (Value *LHSV = dyn_castFNegVal(LHS)) {
+    Instruction *RI = BinaryOperator::CreateFSub(RHS, LHSV);
+    RI->copyFastMathFlags(&I);
+    return RI;
+  }
 
   // A + -B  -->  A - B
   if (!isa<Constant>(RHS))
-    if (Value *V = dyn_castFNegVal(RHS))
-      return BinaryOperator::CreateFSub(LHS, V);
+    if (Value *V = dyn_castFNegVal(RHS)) {
+      Instruction *RI = BinaryOperator::CreateFSub(LHS, V);
+      RI->copyFastMathFlags(&I);
+      return RI;
+    }
 
   // Check for (fadd double (sitofp x), y), see if we can merge this into an
   // integer add followed by a promotion.