[clang] [compiler-rt] [llvm] [AArch64] Extend FMV support to more features (PR #229139)

[via cfe-commits]

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@@ -7389,6 +7389,7 @@ CodeGenFunction::EmitAArch64CpuSupports(ArrayRef<StringRef> FeaturesStrs) {
     // Get features from structure in runtime library
     // struct {
     //   unsigned long long features;
+    //   unsigned long long features2;
     // } __aarch64_cpu_features;
     llvm::Type *STy = llvm::StructType::get(Int64Ty);
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Lukacma wrote:

That wouldn't be backwards compatible. Compiler cannot assume __aarch64_cpu_features has 16bytes for the new code works with older runtime. 

https://github.com/llvm/llvm-project/pull/229139