This bug report: https://bugs.llvm.org/show_bug.cgi?id=43448
Highlights 2 issues with the attribute target AArch64 support.
The first is that the cpu check needs to check the arch rather than
The second is that the AArch64 implementation of GCC's target supports
+<FEATURE> for these targets.
This patch adds these two.
However, passing the AArch64 architecture names in target-cpu
isn't supported by LLVM:
('armv8-a' is not a recognized processor for this target (ignoring processor))
This likely needs to be fixed before this patch can go in.
Note that this is necessary for the ClangBuiltLinux effort.