[PATCH] D155406: [MemCpyOpt] implement multi BB stack-move optimization

Mon Sep 11 20:29:38 PDT 2023

khei4 added a comment.

@vitalybuka Ah, sorry, I was confused and not sure what you said. Did you mean just stripping the src lifetime work?

In D155406#4641099 <https://reviews.llvm.org/D155406#4641099>, @vitalybuka wrote:

> In D155406#4640773 <https://reviews.llvm.org/D155406#4640773>, @bgraur wrote:
>
>> @khei4 the last commit is causing again lots of false positive for tests executed under `asan`.
>>
>> We (the google compilers team) got several tests with no `asan` findings when built before rG3a1409f93da32bf626f76257e0aac71716f2f67e <https://reviews.llvm.org/rG3a1409f93da32bf626f76257e0aac71716f2f67e> that trigger `stack-use-after-scope` when built with this commit.
>>
>> Coming up with a reproducer is pretty time consuming, could you please revert this until one is available?
>
> reverted in efe8aa2e618122e8050af10cc5d6ad83f24ef557 <https://reviews.llvm.org/rGefe8aa2e618122e8050af10cc5d6ad83f24ef557>
>
> If this optimization is critical, maybe you can split this patch in two?
>
> 1. BB stack-move optimization which strips all lifetime markers from src alloca
> 2. insert alloca on dst
>
> Then we can continue related/revert patch 2 as needed.

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  https://reviews.llvm.org/D155406/new/

https://reviews.llvm.org/D155406