Handle -0.0 correctly


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12530 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 21f19b9..e1b0f18 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -313,7 +313,10 @@
 /// specify the full Instruction::OPCODE identifier.
 ///
 Constant *ConstantExpr::getNeg(Constant *C) {
-  return get(Instruction::Sub, getNullValue(C->getType()), C);
+  if (!C->getType()->isFloatingPoint())
+    return get(Instruction::Sub, getNullValue(C->getType()), C);
+  else
+    return get(Instruction::Sub, ConstantFP::get(C->getType(), -0.0), C);
 }
 Constant *ConstantExpr::getNot(Constant *C) {
   assert(isa<ConstantIntegral>(C) && "Cannot NOT a nonintegral type!");