[compiler-rt] [FMV][AArch64] Add initial AT_HWCAP3 / AT_HWCAP4 support (PR #161595)

[Brad Smith via llvm-commits]

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@@ -19,9 +18,14 @@ void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
   if (res)
     return;
 
+  elf_aux_info(AT_HWCAP3, &hwcap3, sizeof hwcap3);
----------------
brad0 wrote:

> Should this and the the call below be taken into account before we early exit above or not?

No, it is intentionally below that as AT_HWCAP3 / AT_HWCAP4 will not exist on older releases so we're just ignoring any error just as Linux / Android will be doing. I honestly don't know why that is there  as I have never seen any software checking that and can't think of any reason to do so.

https://github.com/llvm/llvm-project/pull/161595