This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH][ARM] Improve cond_exec opportunities for immediate shifts for -mrestrict-it
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Kyrylo Tkachov <Kyrylo dot Tkachov at arm dot com>
- Cc: gcc-patches <gcc-patches at gcc dot gnu dot org>, Ramana Radhakrishnan <Ramana dot Radhakrishnan at arm dot com>
- Date: Tue, 10 Sep 2013 09:23:18 +0100
- Subject: Re: [PATCH][ARM] Improve cond_exec opportunities for immediate shifts for -mrestrict-it
- Authentication-results: sourceware.org; auth=none
- References: <014701cead7a$3d242f40$b76c8dc0$ at tkachov@arm.com>
On 09/09/13 17:32, Kyrylo Tkachov wrote:
> Hi all,
>
> Shift operations with an immediate can generate a 16-bit encoding when the
> immediate is 5-bit wide, i.e. in the range [0-31]. Therefore we can use them
> in IT blocks even with the -mrestrict-it rules.
>
> I decided to reuse the "N" constraint with a slight modification by removing
> the !TARGET_32BIT condition from it. The "N" constraint is only used in a few
> patterns that are predicated by TARGET_THUMB1 anyway, so there's no reason for
> the constraint to check for that as well.
>
Hmm, I see no reason why you can't use the M constraint as ARM does.
R.
> Tested arm-none-eabi on model and bootstrapped on Chromebook.
>
> Ok for trunk?
>
> Thanks,
> Kyrill
>
> 2013-09-09 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
>
> * config/arm/arm.md (arm_shiftsi3): New alternative l/l/N.
> * config/arm/constraints.md ("N"): Remove !TARGET_32BIT condition.
>
> 2013-09-09 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
>
> * gcc.target/arm/thumb-ifcvt-2.c: New test.
>
>
> cond-shifts.patch
>
>
> NÂnârÂÂÃÃ)emÃhÃyhiÃÂÂw^âÂÃ
>