From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id DD106385C426; Fri, 17 Apr 2020 21:41:08 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org DD106385C426 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1587159668; bh=5/xt0PA6ZXIUZbKzewRuqB6pLCCTWoqG3IRmfOuSCOo=; h=From:To:Subject:Date:In-Reply-To:References:From; b=LAD7Xa03k2Z7rEl4I6vNZkdPgV/oC3Dy4NeKJsq51+6FZeColq/q2cAT4YE5tqRbK H5J5UPCE+q/vSA/ACw06oRx83aBEcib0tqkuhP6FYbe8R2q/trVNEKV2MLU12PkbfT YJPkguxGJDB5XrPJwshbcTSMn0wODxlVU+nXdHEg= From: "cvs-commit at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/90275] [8/9/10 Regression] ICE: in insert_regs, at cse.c:1128 with -O2 -fno-dce -fno-tree-dce Date: Fri, 17 Apr 2020 21:41:08 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: rtl-optimization X-Bugzilla-Version: 10.0 X-Bugzilla-Keywords: ice-on-valid-code X-Bugzilla-Severity: normal X-Bugzilla-Who: cvs-commit at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: law at redhat dot com X-Bugzilla-Target-Milestone: 8.5 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 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Apr 2020 21:41:09 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D90275 --- Comment #22 from CVS Commits --- The master branch has been updated by Jeff Law : https://gcc.gnu.org/g:3737ccc424c56a2cecff202dd79f88d28850eeb2 commit r10-7781-g3737ccc424c56a2cecff202dd79f88d28850eeb2 Author: Jeff Law Date: Fri Apr 17 15:38:13 2020 -0600 [committed] [PR rtl-optimization/90275] Another 90275 related cse.c fix This time instead of having a NOP copy insn that we can completely igno= re and ultimately remove, we have a NOP set within a multi-set PARALLEL. It triggers, the same failure when the source of such a set is a hard register for t= he same reasons as we've already noted in the BZ and patches-to-date. For prior cases we've been able to mark the insn as a nop set and ignor= e it for the rest of cse_insn, ultimately removing it. That's not really an opt= ion here as there are other sets that we have to preserve. We might be able to fix this instance by splitting the multi-set insn, = but I'm not keen to introduce splitting into cse. Furthermore, the target may = not be able to split the insn. So I considered this is non-starter. What I finally settled on was to use the existing do_not_record machine= ry to ignore the nop set within the parallel (and only that set within the parallel). One might argue that we should always ignore a REG_UNUSED set. But I rejected that idea -- we could have cse-able divmod insns where the first had a REG_UNUSED note for a destination, but the second did not. One might also argue that we could have a nop set without a REG_UNUSED = in a multi-set parallel and thus we could trigger yet another insert_regs IC= E at some point. I tend to think this is a possibility. If we see this hap= pen, we'll have to revisit. PR rtl-optimization/90275 * cse.c (cse_insn): Avoid recording nop sets in multi-set paral= lels when the destination has a REG_UNUSED note.=