https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95144
Bug ID: 95144
Summary: Many AVX-512 functions take an int instead of unsigned
int
Product: gcc
Version: 10.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: e...@coeus-group.com
Target Milestone: ---
There are a bunch of functions in AVX-512F which, according to Intel's
documentation (https://software.intel.com/sites/landingpage/IntrinsicsGuide/),
take an unsigned integer as an argument but GCC's header has the type as a
signed integer.
This causes problems with -Wsign-conversion. Here is an example which will
generate a warning with -Wsign-conversion (or https://godbolt.org/z/kTBTAD if
you prefer):
#include <immintrin.h>
static __m256i foo (__m256i a, unsigned int imm8) {
return _mm256_srai_epi64(a, imm8);
}
__m256i bar(__m256i a) {
return foo(a, 7);
}
AFAICT all the functions which take unsigned imm8 arguments have this problem
in clang. Here is a quick list:
* _mm256_mask_slli_epi16
* _mm256_mask_slli_epi32
* _mm256_mask_slli_epi64
* _mm256_mask_srai_epi16
* _mm256_mask_srai_epi32
* _mm256_mask_srai_epi64
* _mm256_mask_srli_epi32
* _mm256_mask_srli_epi64
* _mm256_maskz_slli_epi16
* _mm256_maskz_slli_epi32
* _mm256_maskz_slli_epi64
* _mm256_maskz_srai_epi16
* _mm256_maskz_srai_epi32
* _mm256_maskz_srai_epi64
* _mm256_maskz_srli_epi32
* _mm256_maskz_srli_epi64
* _mm256_srai_epi64
* _mm512_mask_slli_epi16
* _mm512_mask_slli_epi32
* _mm512_mask_slli_epi64
* _mm512_mask_srai_epi16
* _mm512_mask_srai_epi32
* _mm512_mask_srai_epi64
* _mm512_mask_srli_epi16
* _mm512_mask_srli_epi32
* _mm512_mask_srli_epi64
* _mm512_maskz_slli_epi16
* _mm512_maskz_slli_epi32
* _mm512_maskz_slli_epi64
* _mm512_maskz_srai_epi16
* _mm512_maskz_srai_epi32
* _mm512_maskz_srai_epi64
* _mm512_maskz_srli_epi32
* _mm512_maskz_srli_epi64
* _mm512_slli_epi16
* _mm512_slli_epi32
* _mm512_slli_epi64
* _mm512_srai_epi16
* _mm512_srai_epi32
* _mm512_srai_epi64
* _mm512_srli_epi16
* _mm512_srli_epi32
* _mm512_srli_epi64
* _mm_mask_slli_epi16
* _mm_mask_slli_epi32
* _mm_mask_slli_epi64
* _mm_mask_srai_epi16
* _mm_mask_srai_epi32
* _mm_mask_srai_epi64
* _mm_mask_srli_epi32
* _mm_mask_srli_epi64
* _mm_maskz_slli_epi16
* _mm_maskz_slli_epi32
* _mm_maskz_slli_epi64
* _mm_maskz_srai_epi16
* _mm_maskz_srai_epi32
* _mm_maskz_srai_epi64
* _mm_maskz_srli_epi32
* _mm_maskz_srli_epi64
It looks like clang has the same problem, though ICC and MSVC do not. Here is
an almost identical bug report I filed against LLVM:
https://bugs.llvm.org/show_bug.cgi?id=45931
