From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2601 invoked by alias); 12 Feb 2013 18:26:21 -0000 Received: (qmail 2484 invoked by uid 48); 12 Feb 2013 18:25:46 -0000 From: "meissner at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug lto/50494] gcc.dg/vect/vect-reduc-2char.c fails spuriously on ppc with -flto Date: Tue, 12 Feb 2013 18:26:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: lto X-Bugzilla-Keywords: lto X-Bugzilla-Severity: normal X-Bugzilla-Who: meissner at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Component Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2013-02/txt/msg01247.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50494 Michael Meissner changed: What |Removed |Added ---------------------------------------------------------------------------- Component|target |lto --- Comment #7 from Michael Meissner 2013-02-12 18:25:38 UTC --- I am switching this to LTO instead of target, as it appears to be an LTO bug. Before LTO is run, the alignment of the .rodata section is 16 byte alignment since the array used to initialize the auto array is copied with altivec instructions. After LTO, the alignment of the .rodata section is 4 bytes. The powerpc Altivec instructions ignore the bottom 4 bits of the address, and so depending on what else is linked, the test will randomly fail or succeed. I added attachments from compiling slp-perm-1.c with -O3 -mcpu=power6 -maltivec -save-temps to give the asm files.