[clang] [X86][Clang] Add AVX512 Integer Comparison Intrinsics for constexpr Evaluation (PR #164026)

[Simon Pilgrim via cfe-commits]

https://github.com/RKSimon requested changes to this pull request.

A few very minors - how do you and @shri-acha intend to proceed with the remaining testing?

https://github.com/llvm/llvm-project/pull/164026