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-rw-r--r--lib/Analysis/Lint.cpp40
1 files changed, 34 insertions, 6 deletions
diff --git a/lib/Analysis/Lint.cpp b/lib/Analysis/Lint.cpp
index 9393508..2c8fc0b 100644
--- a/lib/Analysis/Lint.cpp
+++ b/lib/Analysis/Lint.cpp
@@ -504,14 +504,42 @@ void Lint::visitShl(BinaryOperator &I) {
"Undefined result: Shift count out of range", &I);
}
-static bool isZero(Value *V, DataLayout *TD) {
+static bool isZero(Value *V, DataLayout *DL) {
// Assume undef could be zero.
- if (isa<UndefValue>(V)) return true;
+ if (isa<UndefValue>(V))
+ return true;
+
+ VectorType *VecTy = dyn_cast<VectorType>(V->getType());
+ if (!VecTy) {
+ unsigned BitWidth = V->getType()->getIntegerBitWidth();
+ APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+ ComputeMaskedBits(V, KnownZero, KnownOne, DL);
+ return KnownZero.isAllOnesValue();
+ }
+
+ // Per-component check doesn't work with zeroinitializer
+ Constant *C = dyn_cast<Constant>(V);
+ if (!C)
+ return false;
+
+ if (C->isZeroValue())
+ return true;
+
+ // For a vector, KnownZero will only be true if all values are zero, so check
+ // this per component
+ unsigned BitWidth = VecTy->getElementType()->getIntegerBitWidth();
+ for (unsigned I = 0, N = VecTy->getNumElements(); I != N; ++I) {
+ Constant *Elem = C->getAggregateElement(I);
+ if (isa<UndefValue>(Elem))
+ return true;
+
+ APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+ ComputeMaskedBits(Elem, KnownZero, KnownOne, DL);
+ if (KnownZero.isAllOnesValue())
+ return true;
+ }
- unsigned BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
- APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
- ComputeMaskedBits(V, KnownZero, KnownOne, TD);
- return KnownZero.isAllOnesValue();
+ return false;
}
void Lint::visitSDiv(BinaryOperator &I) {