[Attributor] Handle special case when offset equals zero in nonnull deduction
diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 366c347..faf0cdf 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -308,15 +308,16 @@
return nullptr;
}
-static const Value *getBasePointerOfAccessPointerOperand(const Instruction *I,
- int64_t &BytesOffset,
- const DataLayout &DL) {
+static const Value *
+getBasePointerOfAccessPointerOperand(const Instruction *I, int64_t &BytesOffset,
+ const DataLayout &DL,
+ bool AllowNonInbounds = false) {
const Value *Ptr = getPointerOperand(I);
if (!Ptr)
return nullptr;
return GetPointerBaseWithConstantOffset(Ptr, BytesOffset, DL,
- /*AllowNonInbounds*/ false);
+ AllowNonInbounds);
}
ChangeStatus AbstractAttribute::update(Attributor &A) {
@@ -1702,8 +1703,7 @@
return 0;
}
if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
- if (GEP->hasAllZeroIndices() ||
- (GEP->isInBounds() && GEP->hasAllConstantIndices())) {
+ if (GEP->hasAllConstantIndices()) {
TrackUse = true;
return 0;
}
@@ -1718,6 +1718,18 @@
return std::max(int64_t(0), DerefBytes);
}
}
+
+ /// Corner case when an offset is 0.
+ if (const Value *Base = getBasePointerOfAccessPointerOperand(
+ I, Offset, DL, /*AllowNonInbounds*/ true)) {
+ if (Offset == 0 && Base == &AssociatedValue &&
+ getPointerOperand(I) == UseV) {
+ int64_t DerefBytes =
+ (int64_t)DL.getTypeStoreSize(PtrTy->getPointerElementType());
+ IsNonNull |= !NullPointerIsDefined;
+ return std::max(int64_t(0), DerefBytes);
+ }
+ }
if (const Value *Base =
GetPointerBaseWithConstantOffset(UseV, Offset, DL,
/*AllowNonInbounds*/ false)) {