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Re: [PATCH][ARM] Adjust arith_shiftsi for ARMv8-style
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Kyrill 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, 20 May 2014 14:07:48 +0100
- Subject: Re: [PATCH][ARM] Adjust arith_shiftsi for ARMv8-style
- Authentication-results: sourceware.org; auth=none
- References: <53747F0B dot 2060107 at arm dot com>
On 15/05/14 09:47, Kyrill Tkachov wrote:
> Hi all,
>
> Shifted arithmetic operations can never be encoded in 16-bits in and therefore
> can not appear in Thumb2 IT blocks under ARMv8-A rules (and the -mrestrict-it
> rules). This patch adjusts the relevant pattern for that purpose.
>
> Tested and bootstrapped on arm-none-linux-gnueabihf and made sure no performance
> regressions on a number of benchmarks.
>
> This is a bug (not wrong-code though) in -mrestrict-it that affects 4.9 as well
> as trunk, so is it ok to backport it there?
>
>
> Thanks,
> Kyrill
>
> 2014-05-15 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
>
> * config/arm/arm.md (arith_shiftsi): Do not predicate for
> arm_restrict_it.
>
OK both.
R.