Fix a faulty optimization on FP values

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11801 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index fb7dc9849235706ceacbca8d9186c6d8bd891d68..322112a942ef06fbbf1a48fbb3c7c7653b3bfe54 100644 (file)
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -441,7 +441,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
   Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
 
   // X + 0 --> X
-  if (RHS == Constant::getNullValue(I.getType()))
+  if (!I.getType()->isFloatingPoint() &&    // -0 + +0 = +0, so it's not a noop
+      RHS == Constant::getNullValue(I.getType()))
     return ReplaceInstUsesWith(I, LHS);
 
   // X + X --> X << 1