[PATCH] D122789: [compiler-rt] [scudo] Use -mcrc32 on x86 when available

Fri Apr 1 23:29:11 PDT 2022

pengfei added a comment.

In D122789#3424226 <https://reviews.llvm.org/D122789#3424226>, @MaskRay wrote:

> In D122789#3424213 <https://reviews.llvm.org/D122789#3424213>, @pengfei wrote:
>
>> In D122789#3423846 <https://reviews.llvm.org/D122789#3423846>, @MaskRay wrote:
>>
>>> Is this a problem with D105462 <https://reviews.llvm.org/D105462>? Should -msse4.2 imply -mcrc32?
>>
>> -msse4.2 implies -mcrc32: https://godbolt.org/z/xaPccrKx3
>
> That is my understanding of clang/lib/Basic/Targets/X86.cpp:159 , but the error suggested that D105462 <https://reviews.llvm.org/D105462> might change something in an interesting way.
> I am on a trip so do not spend time investigating the root cause.

I a bit suspect the -msse4.2 doesn't specified (correctly). The message in https://bugs.gentoo.org/835870 is a bit confusing. The options in first comment contain -msse4.2, but the following ones say "-msse4.2 [disabled]" or "-mno-sse4 [enabled]". If sse4.2 is disable, no doubt we should add -mcrc32 instead.

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https://reviews.llvm.org/D122789