Consider expression "0.0 - X" as the negation of X if
- this expression is explicitly marked no-signed-zero, or
- no-signed-zero of this expression can be derived from some context.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171922 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index 1b5d004..f2e9813 100644
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -1926,11 +1926,14 @@
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;
}