From: Jeff Law <law@redhat.com>
To: gcc-patches@gcc.gnu.org, richard.sandiford@arm.com
Subject: Re: [PATCH 3/5] Use simplify_subreg_regno in combine.c:subst
Date: Fri, 19 Sep 2014 06:17:00 -0000 [thread overview]
Message-ID: <541BCA70.3020101@redhat.com> (raw)
In-Reply-To: <87d2atnsne.fsf@e105548-lin.cambridge.arm.com>
On 09/18/14 04:13, Richard Sandiford wrote:
> combine.c:subst should refuse to substitute a hard register
> into a subreg if the new subreg would not be simplified to a
> simple hard register, since the result would have to be reloaded.
> This is more for optimisation than correctness, since in theory
> the RA should be able to fix up any unsimplified subregs.
>
>
> gcc/
> * combine.c (subst): Use simplify_subreg_regno rather than
> REG_CANNOT_CHANGE_MODE_P to detect invalid mode changes.
OK independent of other changes.
jeff
next prev parent reply other threads:[~2014-09-19 6:17 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-18 10:07 [PATCH 0/5] Fix handling of word subregs of wide registers Richard Sandiford
2014-09-18 10:09 ` [PATCH 1/5] Allow *_HARD_REG_SET arguments to be const Richard Sandiford
2014-09-19 6:14 ` Jeff Law
2014-09-18 10:10 ` [PATCH 2/5] Tweak subreg_get_info documentation Richard Sandiford
2014-09-19 6:16 ` Jeff Law
2014-09-18 10:13 ` [PATCH 3/5] Use simplify_subreg_regno in combine.c:subst Richard Sandiford
2014-09-19 6:17 ` Jeff Law [this message]
2014-09-18 10:25 ` [PATCH 4/5] Generalise invalid_mode_change_p Richard Sandiford
2014-09-19 17:53 ` Jeff Law
2014-09-22 7:34 ` Richard Sandiford
2014-09-22 16:29 ` Jeff Law
2014-09-18 10:26 ` [PATCH 5/5] Remove CANNOT_CHANGE_MODE_CLASS workaround in i386.c Richard Sandiford
2014-09-19 17:54 ` Jeff Law
2014-09-19 6:14 ` [PATCH 0/5] Fix handling of word subregs of wide registers Jeff Law
2014-09-19 7:24 ` Richard Sandiford
2014-09-19 15:59 ` Jeff Law
2014-09-19 17:14 ` Jeff Law
2014-09-22 7:23 ` Richard Sandiford
2014-09-22 10:49 ` Ajit Kumar Agarwal
2014-09-22 11:26 ` Richard Sandiford
2014-09-22 12:07 ` Ajit Kumar Agarwal
2014-09-22 9:00 ` Andrew Pinski
2014-09-22 11:29 ` Richard Sandiford
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