<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/155411>155411</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Headers][X86] Allow SSE2/AVX2/AVX512F/AVX512BW/AVX512DQ integer multiply intrinsics to be used in constexpr
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            good first issue,
            backend:X86,
            clang:headers,
            constexpr
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          RKSimon
      </td>
    </tr>
</table>

<pre>
    Split off from #152490
```
_mm_mullo_epi32 _mm256_mullo_epi32 _mm512_mullo_epi32
_mm_mullo_epi64 _mm256_mullo_epi64 _mm512_mullo_epi64

_mm_mask_mullo_epi16 _mm256_mask_mullo_epi16 _mm512_mask_mullo_epi16
_mm_mask_mullo_epi32 _mm256_mask_mullo_epi32 _mm512_mask_mullo_epi32
_mm_mask_mullo_epi64 _mm256_mask_mullo_epi64 _mm512_mask_mullo_epi64

_mm_maskz_mullo_epi16 _mm256_maskz_mullo_epi16 _mm512_maskz_mullo_epi16
_mm_maskz_mullo_epi32 _mm256_maskz_mullo_epi32 _mm512_maskz_mullo_epi32
_mm_maskz_mullo_epi64 _mm256_maskz_mullo_epi64 _mm512_maskz_mullo_epi64

_mm_mask_mulhi_epi16 _mm256_mask_mulhi_epi16 _mm512_mask_mulhi_epi16
_mm_mask_mulhi_epu16 _mm256_mask_mulhi_epu16 _mm512_mask_mulhi_epu16

_mm_maskz_mulhi_epi16 _mm256_maskz_mulhi_epi16 _mm512_maskz_mulhi_epi16
_mm_maskz_mulhi_epu16 _mm256_maskz_mulhi_epu16 _mm512_maskz_mulhi_epu16
```
The integer multiple intrinsics (including the masked mulhi variants missed in #152524) are all safe to be used in constexpr - use #152296 for reference
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJx0lEGPmzAQhX-NuVgbwYBJOHBgm0aVempTtXuLDIzBXYMj22y7-fUVlE1IAAkJ9Ib5_J5HNrdWVi1iStgzYXuPd67WJv3-9Sgb3Xq5Lt_T41lJR7UQVBjdUAJhwCBKfOJnJPbHx89OTXNqOqX0Cc8yBHpqGmDxo8QCmEqPfXE06_sv3fXFUb_22Mrt660SxNf-BX2APOiLmIn9BX2OuQW5kydpFvQ55jHXZS3YrPDBuqxEu6xlmxUWSHfpLmvxZoUF0tLgark8uKk-3aoPfQnTrWC6FUw3YB7TLTmaFe7SLXi6rJmaFeak0dbkcP2okcrWYYWGNp1y8qwGwcjWysJSAjvZFqorZVtRVyPtgVjSgUjfuJG8dZY20losqWzHU8wgIpBQbpBypajlAqnTNEfajf8VurUO_54Nfeq1sQ-SmAptqEGBBtsCvTINyyRMuIdpsGUxBOE2Yl6dCohZUZZbvgWGYZFsE8E4F0UochEWW_RkCj4wfwdxEPqJzzbo-4Evyjjn0S7eFiWJfGy4VBul3pqNNpUnre0wDRiLgsBTPEdlh_sLoNK6pEIa6-jwEwEg8IkA5Lx4xbYkYfayi69qoXhbkTCrkZdo7E3_CN0rbO-ZtF_7Ke8qSyJfSevszY2TTg3355eRwvaEPffLsD3NlNJ_6PH4GQgcsp8v44sFcLh-Pf-6fu6_PU75fTrlldF4nVFp7dzZkjAjA7mSru7yTaEbAofe6vh6Ohv9GwtH4DBskCVwGDfyLYV_AQAA__9j2AuE">