[PATCH] D39712: [ARM] Add an alias for psr

[Oliver Stannard via Phabricator via llvm-commits]

olista01 added reviewers: javed.absar, rengolin.
olista01 added a comment.

Hi Leslie,

As far as I can tell, this is a gcc extension (it's not in any architecture reference manual I can find), which I can't find any documentation for. Is this correct, or is there some documentation I've missed? If I'm right, I'm not sure that there's any compelling reason to support this in LLVM. I've added Renato, who might know more about our policy for adding these sort of non-standard extensions.

If we do implement it, this isn't the right way to do it, you have given the "psr" operand a different encoding than "xpsr". In gcc's implementation, "psr" and "xpsr" result in exactly the same instructions. I've added Javed, who implemented this table-driver operand parsing, he might have some ideas about the best way to implement aliases.

As for the test, this is not the right file to put it in, I'd suggest adding it to test/MC/ARM/thumb2-mclass.s instead.


Repository:
  rL LLVM

https://reviews.llvm.org/D39712