[PATCH] D124728: Allow pointer types for atomicrmw xchg

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/lib/CodeGen/AtomicExpandPass.cpp:548
+      (AI->getValOperand()->getType()->isFloatingPointTy() ||
+       (Kind != TargetLoweringBase::AtomicExpansionKind::CmpXChg &&
+        AI->getValOperand()->getType()->isPointerTy()))) {
----------------
tkf wrote:
> efriedma wrote:
> > Do you also want to check for AtomicExpansionKind::None here?
> I saw the failure from LegalizeDAG in an AArch64 test that does atomicrmw xchg on floating point. It occurs with `AtomicExpansionKind::None`. This is the failure in LegalizeDAG I mentioned above. Since presumably the legalization does not support xchg of floats, we need to convert it on xchg of ints here.
> 
> I think making this part simple requires adding supports to the legalization. But I'm not familiar with that part of LLVM.
> 
No, I meant if we have pointer, and the expansion kind is None.  I wasn't suggesting you change what we do for floating-point ops.


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  https://reviews.llvm.org/D124728/new/

https://reviews.llvm.org/D124728