some clang AVX instricts looks broken
Rozhuk Ivan
rozhuk.im at gmail.com
Sun May 1 20:51:31 UTC 2016
Hi!
I try port some SSE code to AVX and found that clang instricts _mm256_extract* broken:
_mm256_extract_epi8(__aymm0, 0) - BAD result
_mm256_extract_epi8(__aymm0, 0) & 0xff - OK
_mm_extract_epi8(_mm256_extractf128_si256(__aymm0, 0), 0) - OK
Same time: _mm256_extract_epi8(__aymm0, 0) build with GCC - OK.
CLANG:
static __inline int __attribute__((__always_inline__, __nodebug__))
_mm256_extract_epi8(__m256i __a, int const __imm)
{
__v32qi __b = (__v32qi)__a;
return __b[__imm & 31];
}
GCC:
extern __inline int __attribute__((__gnu_inline__, __always_inline__, __artificial__))
_mm256_extract_epi8 (__m256i const __X, int const __N)
{
__m128i __Y = _mm256_extractf128_si256 (__X, __N >> 4);
return _mm_extract_epi8 (__Y, __N % 16);
}
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