Consider expression "0.0 - X" as the negation of X if

[oota-llvm.git] / lib / IR / Instructions.cpp

diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index 1b5d004978c59b0aec452ea65eb1050853f93195..f2e9813bc638848e0245a2731239ff3ed4717eee 100644 (file)
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -1926,11 +1926,14 @@ bool BinaryOperator::isNeg(const Value *V) {
   return false;
 }
 
-bool BinaryOperator::isFNeg(const Value *V) {
+bool BinaryOperator::isFNeg(const Value *V, bool IgnoreZeroSign) {
   if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(V))
     if (Bop->getOpcode() == Instruction::FSub)
-      if (Constant* C = dyn_cast<Constant>(Bop->getOperand(0)))
-        return C->isNegativeZeroValue();
+      if (Constant* C = dyn_cast<Constant>(Bop->getOperand(0))) {
+        if (!IgnoreZeroSign)
+          IgnoreZeroSign = cast<Instruction>(V)->hasNoSignedZeros();
+        return !IgnoreZeroSign ? C->isNegativeZeroValue() : C->isZeroValue();
+      }
   return false;
 }