[PATCH] D117356: InstructionCombining: avoid eliding mismatched alloc/free pairs

Wed Jan 19 12:45:32 PST 2022

ychen added a comment.

In D117356#3255986 <https://reviews.llvm.org/D117356#3255986>, @jyknight wrote:

> In D117356#3245221 <https://reviews.llvm.org/D117356#3245221>, @ychen wrote:
>
>> In D117356#3245161 <https://reviews.llvm.org/D117356#3245161>, @durin42 wrote:
>>
>>> Ah, @jyknight bailed me out. That's https://github.com/llvm/llvm-project/issues/40384 which looks related, yes. I suspect that would be resolved by this patch.
>>
>> Agreed that this patch could fix it. However, the underlying issue is that the mismatch is generated by LLVM itself. IMHO preventing the mismatch is a better approach (which D97735 <https://reviews.llvm.org/D97735> would do, I think we should land that instead. @rsmith (thought?)
>
> I don't believe this commit will address that bug.
>
> However, the follow-on work Augie has planned, to move the allocator information to attributes supplied by the frontend will -- because it will enable us to stop treating C++ allocators as "builtin" -- with all the other side-effects that has, while preserving the ability to mark them as removable allocation functions (what we actually _want_).

That sounds very promising. Thanks! (Yep, strictly speaking, this covers the issue instead of fixing it.)

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https://reviews.llvm.org/D117356