[llvm-bugs] [Bug 45931] New: Many AVX-512 functions take an int instead of unsigned int

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=45931

            Bug ID: 45931
           Summary: Many AVX-512 functions take an int instead of unsigned
                    int
           Product: new-bugs
           Version: unspecified
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: clang at evan.coeusgroup.com
                CC: htmldeveloper at gmail.com, llvm-bugs at lists.llvm.org

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 clang'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 GCC has the same problem, though ICC and MSVC do not.

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