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Re: [PATCH][GCC][mid-end] Correct subreg no-op handling for big-endian vec_select.
- From: Jeff Law <law at redhat dot com>
- To: Tamar Christina <tamar dot christina at arm dot com>, gcc-patches at gcc dot gnu dot org
- Cc: nd at arm dot com, rguenther at suse dot de, ian at airs dot com
- Date: Wed, 27 Jun 2018 21:11:36 -0600
- Subject: Re: [PATCH][GCC][mid-end] Correct subreg no-op handling for big-endian vec_select.
- References: <20180619141104.GA28745@arm.com>
On 06/19/2018 08:11 AM, Tamar Christina wrote:
> Hi All,
>
> Previously GCC's no-op detection could would consider something a no-op even when the
> mode change is not directly possible. This caused subregs that shouldn't be removed
> to be treated as a no-op and deleted.
>
> Regtested on armeb-none-eabi and no regressions.
> Bootstrapped on arm-none-linux-gnueabihf and no issues.
>
> Ok for trunk? and for backport to GCC 8?
>
> Thanks,
> Tamar
>
> gcc/
> 2018-06-19 Tamar Christina <tamar.christina@arm.com>
>
> PR target/84711
> * rtlanal.c (set_noop_p): Constrain on mode change,
> include hard-reg-set.h
>
OK. Though please include a testcase. I believe you had
big-endian-subreg.c in the original target specific approach to fixing
this problem. That'd be fine to re-use here.
jeff