[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - add MMX/SSE/AVX/AVX512 PMULHRSW intrinsics to be used in constexpr

[RKSimon]

Similar to #152524 - add handling for __builtin_ia32_pmulhrs to VectorExprEvaluator::VisitCallExpr and InterBuiltin.cpp

_mm_mulhrs_pi16
_mm_mulhrs_epi16 _mm256_mulhrs_epi16 _mm512_mulhrs_epi16
_mm_mask_mulhrs_epi16 _mm256_mask_mulhrs_epi16 _mm512_mask_mulhrs_epi16
_mm_maskz_mulhrs_epi16 _mm256_maskz_mulhrs_epi16 _mm512_maskz_mulhrs_epi16

Further info on how to constant fold PMULHRSW can be found in simplifyX86pmulh in X86InstCombineIntrinsic.cpp

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor is working on this issue. If someone is assigned to the issue or claimed to be working on it, ping the person. After one week without a response, the assignee may be changed.
2. Leave a comment indicating that you are working on the issue, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-backend-x86

Author: Simon Pilgrim (RKSimon)

Similar to #152524 - add handling for __builtin_ia32_pmulhrs to VectorExprEvaluator::VisitCallExpr and InterBuiltin.cpp ``` _mm_mulhrs_pi16 mm_mulhrs_epi16 mm256_mulhrs_epi16 mm512_mulhrs_epi16 mm_mask_mulhrs_epi16 mm256_mask_mulhrs_epi16 mm512_mask_mulhrs_epi16 mm_maskz_mulhrs_epi16 mm256_maskz_mulhrs_epi16 mm512_maskz_mulhrs_epi16 ```

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Simon Pilgrim (RKSimon)

Similar to #152524 - add handling for __builtin_ia32_pmulhrs to VectorExprEvaluator::VisitCallExpr and InterBuiltin.cpp ``` _mm_mulhrs_pi16 mm_mulhrs_epi16 mm256_mulhrs_epi16 mm512_mulhrs_epi16 mm_mask_mulhrs_epi16 mm256_mask_mulhrs_epi16 mm512_mask_mulhrs_epi16 mm_maskz_mulhrs_epi16 mm256_maskz_mulhrs_epi16 mm512_maskz_mulhrs_epi16 ```

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Simon Pilgrim (RKSimon)

Similar to #152524 - add handling for __builtin_ia32_pmulhrs to VectorExprEvaluator::VisitCallExpr and InterBuiltin.cpp ``` _mm_mulhrs_pi16 mm_mulhrs_epi16 mm256_mulhrs_epi16 mm512_mulhrs_epi16 mm_mask_mulhrs_epi16 mm256_mask_mulhrs_epi16 mm512_mask_mulhrs_epi16 mm_maskz_mulhrs_epi16 mm256_maskz_mulhrs_epi16 mm512_maskz_mulhrs_epi16 ```

[Temperz87]

Hey @RKSimon can I be assigned to this issue?

[RKSimon]

@Temperz87 Now that interp__builtin_elementwise_int_binop uses callbacks it should be easy to add handling to InterpBuiltin.cpp as well