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

[Phoebe Wang via Phabricator via cfe-commits]

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In D122789#3446865 <https://reviews.llvm.org/D122789#3446865>, @MaskRay wrote:

> To kurly (original Gentoo reporter):
>
>   printf '#include <smmintrin.h>\n#include <stdint.h>\nuint32_t computeHardwareCRC32(uint32_t Crc, uint32_t Data) { return _mm_crc32_u32(Crc, Data); }' > a.c
>
>
>
>   % clang -m32 -march=i686 -msse4.2 -c a.c  # seems to compile fine
>   % gcc -m32 -march=i686 -msse4.2 -c a.c
>   % gcc -m32 -march=i686 -mcrc32 -c a.c
>   In file included from a.c:1:
>   a.c: In function ‘computeHardwareCRC32’:
>   /usr/lib/gcc/x86_64-linux-gnu/11/include/smmintrin.h:839:1: error: inlining failed in call to ‘always_inline’ ‘_mm_crc32_u32’: target specific option mismatch
>     839 | _mm_crc32_u32 (unsigned int __C, unsigned int __V)
>         | ^~~~~~~~~~~~~
>   a.c:3:69: note: called from here
>       3 | uint32_t computeHardwareCRC32(uint32_t Crc, uint32_t Data) { return _mm_crc32_u32(Crc, Data); }
>         |                                                                     ^~~~~~~~~~~~~~~~~~~~~~~~
>
> I have some older GCC and latest GCC (2022-04, multilib), `gcc -m32 -march=i686 -msse4.2 -c a.c`  builds while `-mcrc32` doesn't.
>
> I suspect we should revert the `-mcrc32` change. The `__CRC32__` macro may be fine.

Thanks for the infromation. I got the same result. That's weird. I believe at some point, GCC supported `-mcrc32`. @hjl.tools, did GCC intentionally remove the support for `-mcrc32`?


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