From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id EDFA338582B3; Wed, 10 Jan 2024 09:19:15 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org EDFA338582B3 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1704878355; bh=jfFGIvAexC7/v7PI5Uu54qypdh1zsO6QF3b9gGeBq48=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Qps9zOnSQS/Zqh5qcBNOgQfZ8ZHPeMDTv0JJUxoknVWa2Jregk7smp5ffdfr53N3X KzdJZnYcZ9kXQLcshdmgOxQ1waUryoHr4qCjLNbNgkWcRyoLH7WR1jH8vyiuoqLgoN +DVkLXPyrhIzwZlvSV/Zrnneqk4w37VGpplLMqWM= From: "jakub at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/113059] [14 regression] fftw fails tests for -O3 -m32 -march=znver2 since r14-6210-ge44ed92dbbe9d4 Date: Wed, 10 Jan 2024 09:19:15 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 14.0 X-Bugzilla-Keywords: wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: jakub at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 14.0 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113059 --- Comment #12 from Jakub Jelinek --- (In reply to Richard Biener from comment #11) > IMHO REG_UNUSED notes should stay correct or be removed. Instead of a fu= ll > solution can we just wipe them in postreload-cse as we know that pass will > break them? Any user then should recompute the notes. Originally pass > properties were thought of a vehicle indicating these kind of IL features, > so we > could add PROP_rtl_unused_notes and if not set treat them as possibly > invalid when present (instead of actively wiping them), and when a pass > requires them re-compute them. >=20 > The problem with properties is that they are always set/unset irrespective > of whether a pass did something destroying it. That could be > circumvented by postreload-cse only clearing the flag when it does > something. >=20 > Not (re-)using pass properties for this but a flag in struct function > works as well of course (or treat it as part of the DF state). I was hoping we could have some df checking which would discover invalid REG_UNUSED notes and so we would know which passes need tweaking, but I'm afraid my df knowledge is insufficient for that. Dunno how often postreload-cse actually extends life time of some register, which should determine whether we want to drop REG_UNUSED notes uncondition= ally at the end of postreload-cse, or whether we e.g. want just some flag whether we've extended lifetime of something during it and only remove REG_UNUSED n= otes if that flag is set.=