================
@@ -358,49 +360,64 @@ UseCaptureKind llvm::DetermineUseCaptureKind(
// Volatile stores make the address observable.
auto *ACXI = cast<AtomicCmpXchgInst>(I);
if (U.getOperandNo() == 1 || U.getOperandNo() == 2 || ACXI->isVolatile())
- return UseCaptureKind::MAY_CAPTURE;
- return UseCaptureKind::NO_CAPTURE;
+ return CaptureInfo::otherOnly();
+ return CaptureInfo::none();
}
case Instruction::GetElementPtr:
// AA does not support pointers of vectors, so GEP vector splats need to
// be considered as captures.
if (I->getType()->isVectorTy())
- return UseCaptureKind::MAY_CAPTURE;
- return UseCaptureKind::PASSTHROUGH;
+ return CaptureInfo::otherOnly();
+ return CaptureInfo::retOnly();
case Instruction::BitCast:
case Instruction::PHI:
case Instruction::Select:
case Instruction::AddrSpaceCast:
// The original value is not captured via this if the new value isn't.
- return UseCaptureKind::PASSTHROUGH;
+ return CaptureInfo::retOnly();
case Instruction::ICmp: {
unsigned Idx = U.getOperandNo();
unsigned OtherIdx = 1 - Idx;
- if (auto *CPN = dyn_cast<ConstantPointerNull>(I->getOperand(OtherIdx))) {
+ if (isa<ConstantPointerNull>(I->getOperand(OtherIdx)) &&
+ cast<ICmpInst>(I)->isEquality()) {
+ // TODO(captures): Remove these special cases once we make use of
+ // captures(address_is_null).
+
// Don't count comparisons of a no-alias return value against null as
// captures. This allows us to ignore comparisons of malloc results
// with null, for example.
- if (CPN->getType()->getAddressSpace() == 0)
+ if (U->getType()->getPointerAddressSpace() == 0)
if (isNoAliasCall(U.get()->stripPointerCasts()))
- return UseCaptureKind::NO_CAPTURE;
+ return CaptureInfo::none();
if (!I->getFunction()->nullPointerIsDefined()) {
auto *O = I->getOperand(Idx)->stripPointerCastsSameRepresentation();
// Comparing a dereferenceable_or_null pointer against null cannot
// lead to pointer escapes, because if it is not null it must be a
// valid (in-bounds) pointer.
const DataLayout &DL = I->getDataLayout();
if (IsDereferenceableOrNull && IsDereferenceableOrNull(O, DL))
- return UseCaptureKind::NO_CAPTURE;
+ return CaptureInfo::none();
}
+
+ // Check whether this is a comparison of the base pointer against
+ // null. We can also strip inbounds GEPs, as inbounds preserves
+ // the null-ness of the pointer.
+ Value *Stripped = U.get();
+ if (!NullPointerIsDefined(I->getFunction(),
+ U->getType()->getPointerAddressSpace()))
+ Stripped = Stripped->stripInBoundsOffsets();
+ if (Stripped == Base)
----------------
nikic wrote:
Yeah, I wasn't sure about that. I've dropped it for now. We can add it back if
it's useful for phase ordering reasons.
https://github.com/llvm/llvm-project/pull/125880
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
