[PATCH] D145131: [Arm][AArch64] Setting IsX18ReservedByDefault() to true for Unknown OSes

[David Spickett via Phabricator via llvm-commits]

DavidSpickett removed a reviewer: ARMDavidSpickett.
DavidSpickett added a comment.

Please confirm that the CI failures are not due to this change and add/update an existing test case for this change. Presumably a triple of "aarch64-notarealos-gnueabi" will trigger this.

There is a chance someone out there is relying on this, but that seems like a risky position to begin with. If they are, they will probably just get less efficient code, so I don't object to the change.

There should be a release note for this, for those minority of cases. I know there are command line options for reserving registers (`-ffixed-`?), please check if those would allow folks to override this and if so add that to the note. "if you do not want this behaviour you can use....".

> [Arm][AArch64]

In the context of llvm, ARM = Arm 32 bit, AArch64 = Arm 64 bit (I know, it's hardly elegant). So you just need [AArch64]. Ideally `[llvm][AArch64]`.

Finally, do we know what RISCV does for this? They have a method by the same name and we might as well make clang consistent if we can.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D145131/new/

https://reviews.llvm.org/D145131