[libwebp] Fix SIMD patch quirks #32985
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LilyWangLL
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LilyWangLL
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Aug 7, 2023
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dg0yt
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Aug 7, 2023
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| - set(SIMD_ENABLE_FLAGS "/arch:AVX;/arch:SSE2;;;;") | ||
| + set(SIMD_ENABLE_FLAGS ";/arch:SSE2;;;;") # /arch:AVX is too much for SSE4 |
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This is based on #21644 / #14568.
IMO this is a pessimistic build-time fix for generating invalid code for non-avx sse4.1 CPUs (#14568). AFAIU the actual implementation is chosen at runtime. So the proper fix would be to choose the the sse4.1 code only if the CPU supports AVX if the compiler is MSVC. Something around these lines:
https://github.com/webmproject/libwebp/blob/dd7364c3cefe0f5c0b3c18c3b1887d353f90fc1f/src/dsp/cpu.c#L158-L167
But I don't want to touch that now. This cmake code path is not used for modern versions of MSVC.
LilyWangLL
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Aug 8, 2023
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Reverts #21644.
Fixes #14568.
Fixes #32940.