[PATCH] [AArch64] Add add/sub/cmp/cmn aliases to MC AsmParser

Arnaud A. de Grandmaison arnaud.degrandmaison at arm.com
Fri Jul 11 15:14:28 PDT 2014

Only the cmn -> adds / cmp -> subs aliases  are part of the ARM ARM.

The other aliases, in this patch or my previous patch, do not appear in the
ARM ARM, because they are pseudos in ARM's parlance, i.e. cases that a
compiler would not generate by itself, but that assemblers should accept,
for compatibility between different assemblers. Those pseudos are used in
already existing hand written assembly code : for example, the bic with
immediate is used at several places in the linux kernel.

The goal  is to be able to assemble code which other assemblers do accept,
so that users can switch fully to llvm for their toolchain. I do not know if
such a compatibility document exists, so  let me check that ; but I agree
that this  document is necessary so that there is an official , reasonable
and documented common ground to support.  

Arnaud A. de Grandmaison

-----Original Message-----
From: llvm-commits-bounces at cs.uiuc.edu
[mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Tim Northover
Sent: 11 July 2014 22:39
To: Renato Golin
Cc: LLVM Commits
Subject: Re: [PATCH] [AArch64] Add add/sub/cmp/cmn aliases to MC AsmParser

> It is possible that GCC already does that and maybe that's the reason 
> for the patch? (Arnaud?)

That almost certainly is the direct reason. But ARM should be strongly
encouraged to document it in the ARM ARM if it becomes some kind of de facto
standard (assuming it's not there already).


llvm-commits mailing list
llvm-commits at cs.uiuc.edu

More information about the llvm-commits mailing list