From: Vladimir Makarov <vmakarov@redhat.com>
To: Joel Hutton <Joel.Hutton@arm.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: nd <nd@arm.com>, "ebotcazou@adacore.com" <ebotcazou@adacore.com>
Subject: Re: [GCC][IRA] Revert 11b8091fb to fix Bug 93221
Date: Tue, 21 Jan 2020 19:27:00 -0000 [thread overview]
Message-ID: <03413895-e1a6-0e46-c64a-436234e03d4a@redhat.com> (raw)
In-Reply-To: <586c7e2d-5305-7bd2-8d57-85693feffb16@arm.com>
On 1/21/20 12:20 PM, Joel Hutton wrote:
> Hi all,
>
> A previous change to simplify LRA introduced in 11b809 (From-SVN:
> r279550) disabled hard register splitting for -O0. This causes a problem
> on aarch64 in cases where parameters are passed in multiple registers
> (in the bug report an OI passed in 2 V4SI registers). This is mandated
> by the AAPCS.
I see. I suspected that it can cause the problem but I thought the
probability is very small for this. I was wrong. We should revert it
at least for now. Correct work of GCC is more important than saving
cycles in -O0 mode.
> Vlad, Eric, do you have a preferred alternate solution to reverting the
> patch?
I am in favour of reverting the patch now. But may be Eric can provide
another version of the patch not causing the arm problem. I am ready to
reconsider this too. So I guess the decision is upto Eric.
> Previously discussed here:
> https://gcc.gnu.org/ml/gcc-patches/2019-12/msg01414.html
> Bug report: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93221
>
> Bootstrapped and regression tested on aarch64
>
> Changelog:
>
> 2020-01-21 Joel Hutton <Joel.Hutton@arm.com\>
>
> * ira.c (ira): Revert use of simplified LRA algorithm.
>
> gcc/testsuite/ChangeLog:
>
> 2020-01-21 Joel Hutton <Joel.Hutton@arm.com\>
>
> PR bug/93221
> * gcc.target/aarch64/pr93221.c: New test.
>
next prev parent reply other threads:[~2020-01-21 19:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 18:35 Joel Hutton
2020-01-21 19:27 ` Vladimir Makarov [this message]
2020-01-27 15:54 ` [Ping][GCC][IRA] " Joel Hutton
2020-01-28 9:31 ` Eric Botcazou
2020-01-28 10:01 ` Joel Hutton
2020-01-28 15:34 ` Vladimir Makarov
2020-01-21 20:04 ` [GCC][IRA] " Jakub Jelinek
2020-01-21 21:06 ` Joel Hutton
2020-01-21 21:36 ` Joel Hutton
2020-01-21 21:39 ` Joel Hutton
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