From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8815 invoked by alias); 27 Aug 2006 20:28:54 -0000 Received: (qmail 8783 invoked by uid 48); 27 Aug 2006 20:28:48 -0000 Date: Sun, 27 Aug 2006 20:28:00 -0000 Message-ID: <20060827202848.8781.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/28778] [4.0/4.1/4.2 Regression] alias bug with cast and call clobbered In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "mmitchel at gcc dot gnu dot org" Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2006-08/txt/msg02380.txt.bz2 List-Id: ------- Comment #26 from mmitchel at gcc dot gnu dot org 2006-08-27 20:28 ------- I don't understand how TBAA is interacting with the may-alias information. In particular, TBAA doesn't say anything about casts; it says something about loads and stores. In particular, TBAA forbids accessing storage of type A through a pointer to type B, given certain constraints on A and B. It does not forbid casting an A* to a B*. Why are the optimizers pruning may-alias sets on casts? Why isn't the fix just to stop them from doing that? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28778