From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rock.gnat.com (rock.gnat.com [205.232.38.15]) by sourceware.org (Postfix) with ESMTPS id 7F6DF3858D28; Wed, 15 Dec 2021 08:22:26 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 7F6DF3858D28 Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 41965116342; Wed, 15 Dec 2021 03:22:26 -0500 (EST) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id luNeWKRMtsuJ; Wed, 15 Dec 2021 03:22:26 -0500 (EST) Received: from free.home (tron.gnat.com [IPv6:2620:20:4000:0:46a8:42ff:fe0e:e294]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by rock.gnat.com (Postfix) with ESMTPS id A599A11633D; Wed, 15 Dec 2021 03:22:25 -0500 (EST) Received: from livre (livre.home [172.31.160.2]) by free.home (8.15.2/8.15.2) with ESMTPS id 1BF8MHEW036501 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Dec 2021 05:22:18 -0300 From: Alexandre Oliva To: Jeff Law Cc: gcc-patches@gcc.gnu.org, zsojka@seznam.cz, wilson@gcc.gnu.org Subject: Re: [PR103302] skip multi-word pre-move clobber during lra Organization: Free thinker, does not speak for AdaCore References: <74d2af86-c1c4-0842-b319-09e76b3bf633@gmail.com> <4bf89538-8c3c-59a7-378b-d02982e6a5ea@gmail.com> Errors-To: aoliva@lxoliva.fsfla.org Date: Wed, 15 Dec 2021 05:22:17 -0300 In-Reply-To: <4bf89538-8c3c-59a7-378b-d02982e6a5ea@gmail.com> (Jeff Law's message of "Wed, 8 Dec 2021 23:03:12 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 X-Spam-Status: No, score=-12.2 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Dec 2021 08:22:27 -0000 On Dec 9, 2021, Jeff Law wrote: >> I found a similar pattern of issuing clobbers for multi-word moves, but >> not when reload_in_progress, in expr.c:emit_move_complex_parts. I don't >> have a testcase, but I'm tempted to propose '!lra_in_progress &&' for it >> as well. Can you think of any reason not to? > The only reason I can think of is we're in stage3 :-)=C2=A0 It'd be a lot > easier to green light that if we could trigger an issue. I have not found the cycles to try to construct a testcase to trigger the issue, but before moving on, I have regstrapped this on x86_64-linux-gnu, so, at least for now, I propose it for the next release cycle. Ok to install then? [PR103302] skip multi-part clobber during lra for complex parts too From: Alexandre Oliva As with the earlier patch, avoid emitting clobbers that we used to avoid during reload also during LRA, now when moving complex multi-part values. We don't have a testcase for this one. for gcc/ChangeLog PR target/103302 * expr.c (emit_move_complex_parts): Skip clobbers during lra. --- gcc/expr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/expr.c b/gcc/expr.c index 0365625e7b835..30d1735ec29ce 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -3736,7 +3736,7 @@ emit_move_complex_parts (rtx x, rtx y) /* Show the output dies here. This is necessary for SUBREGs of pseudos since we cannot track their lifetimes correctly; hard regs shouldn't appear here except as return values. */ - if (!reload_completed && !reload_in_progress + if (!reload_completed && !reload_in_progress && !lra_in_progress && REG_P (x) && !reg_overlap_mentioned_p (x, y)) emit_clobber (x); =20 --=20 Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/ Free Software Activist GNU Toolchain Engineer Disinformation flourishes because many people care deeply about injustice but very few check the facts. Ask me about