[clang] [compiler-rt] [llvm] [X86] Support APXF to enable __builtin_cpu_supports. (PR #80636)

[Shengchen Kan via cfe-commits]

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@@ -1845,6 +1845,7 @@ bool sys::getHostCPUFeatures(StringMap<bool> &Features) {
   Features["prefetchi"]  = HasLeaf7Subleaf1 && ((EDX >> 14) & 1);
   Features["usermsr"]  = HasLeaf7Subleaf1 && ((EDX >> 15) & 1);
   Features["avx10.1-256"] = HasLeaf7Subleaf1 && ((EDX >> 19) & 1);
+  Features["apxf"] = HasLeaf7Subleaf1 && ((EDX >> 21) & 1);
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KanRobert wrote:

My understanding is "apxf" here is used by front-end for FMV, right?
What would happen if there is "apxf" in the IR after this patch?

https://github.com/llvm/llvm-project/pull/80636