[X86] Enable EVEX512 when host CPU has AVX512

[phoebewang]

This is used when -march=native run on an unknown CPU to old version of LLVM.

[github-actions[bot]]

:warning: C/C++ code formatter, clang-format found issues in your code. :warning:

You can test this locally with the following command:

``````````bash git-clang-format --diff 8d5386669ed63548daf1bee415596582d6d78d7d 9e84562bbea4d733199bef8d760c8e7a02bdb941 -- llvm/lib/TargetParser/Host.cpp ``````````

View the diff from clang-format here.

``````````diff diff --git a/llvm/lib/TargetParser/Host.cpp b/llvm/lib/TargetParser/Host.cpp index e911d15498..c71adadbb7 100644 --- a/llvm/lib/TargetParser/Host.cpp +++ b/llvm/lib/TargetParser/Host.cpp @@ -1801,7 +1801,7 @@ bool sys::getHostCPUFeatures(StringMap &Features) { Features["rtm"] = HasLeaf7 && ((EBX >> 11) & 1); // AVX512 is only supported if the OS supports the context save for it. Features["avx512f"] = HasLeaf7 && ((EBX >> 16) & 1) && HasAVX512Save; - Features["evex512"] = Features["avx512f"]; + Features["evex512"] = Features["avx512f"]; Features["avx512dq"] = HasLeaf7 && ((EBX >> 17) & 1) && HasAVX512Save; Features["rdseed"] = HasLeaf7 && ((EBX >> 18) & 1); Features["adx"] = HasLeaf7 && ((EBX >> 19) & 1); ``````````

[phoebewang]

cherry-pick https://github.com/llvm/llvm-project/commit/b3291793f11924a3b62601aabebebdcfbb12a9a1

[nikic]

/cherry-pick b3291793f11924a3b62601aabebebdcfbb12a9a1

[llvmbot]

/pull-request llvm/llvm-project#90545