[PATCH] D140100: [SLP]Integrate looking through shuffles logic into ShuffleInstructionBuilder.

Wed Jan 4 07:56:10 PST 2023

ABataev added a comment.

In D140100#4026248 <https://reviews.llvm.org/D140100#4026248>, @alexfh wrote:

> In D140100#4024152 <https://reviews.llvm.org/D140100#4024152>, @ABataev wrote:
>
>> In D140100#4024147 <https://reviews.llvm.org/D140100#4024147>, @alexfh wrote:
>>
>>> In D140100#4018269 <https://reviews.llvm.org/D140100#4018269>, @asmok-g wrote:
>>>
>>>> Heads-up: This has caused a change in behavior when using `#pragma unroll` in some test using SIMD. In other words, using `#pragma unroll` results in a different output than without it. I'm preparing a reduced test case.
>>>
>>> I've got a reduced IR file for that case: F26088275: q.ll <https://reviews.llvm.org/F26088275>
>>>
>>>   $ old-clang -O2 q.ll && ./a.out
>>>   0.0
>>>   $ new-clang -O2 q.ll && ./a.out
>>>   5.0
>>>
>>> Please fix or revert the patch, if there's no trivial fix.
>>>
>>> Thanks!
>>
>> Thanks for the reproducer, will investigate it.
>
> Alexey, could you revert the commit in the meantime?

It is not so easy, there are several commits on top of it already. I just started looking at it, hope to provide a fix in 1-2hrs, if it will take more time, I'll revert it.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D140100/new/

https://reviews.llvm.org/D140100