From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7385 invoked by alias); 8 Jan 2010 02:44:09 -0000 Received: (qmail 5277 invoked by uid 48); 8 Jan 2010 02:43:47 -0000 Date: Fri, 08 Jan 2010 02:44:00 -0000 Message-ID: <20100108024347.5276.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug rtl-optimization/42631] [4.5 Regression] "-fcompare-debug failure" with "-O1 -funroll-loops" In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "aoliva at gcc dot gnu dot org" 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: 2010-01/txt/msg00881.txt.bz2 ------- Comment #10 from aoliva at gcc dot gnu dot org 2010-01-08 02:43 ------- Well, it's not like accessing an uninitialized variable is well-defined, so it's not like our splitting into multiple webs is wrong, or could possibly generate incorrect results. The only reason we notice this is that it gets us different results precisely for a test framework designed to be picky about minute differences, even if in the end they don't make any difference in terms of program behavior. Just to be clear, although the references were *originally* part of a loop, when the loop was unrolled, the failing bits became part of an pre-loop block, so there's nothing that could actually fail here in terms of codegen, AFAICT. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42631