From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25247 invoked by alias); 14 May 2009 11:04:33 -0000 Received: (qmail 22950 invoked by uid 48); 14 May 2009 11:04:20 -0000 Date: Thu, 14 May 2009 11:04:00 -0000 Message-ID: <20090514110420.22948.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug middle-end/40141] [4.3 Regression] accessing aliased __m128 miscompiles In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "rguenth 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: 2009-05/txt/msg01222.txt.bz2 ------- Comment #1 from rguenth at gcc dot gnu dot org 2009-05-14 11:04 ------- Confirmed. That's the SMTs do not include ref-all stuff bug so DCE removes the initialization. extern void abort (void); typedef int __m128 __attribute__((vector_size(16), may_alias)); typedef float floatA __attribute__((may_alias)); int main() { __m128 x = { 0, 0, 0, 0 }; int i; for (i = 0; i < 4; ++i) { const float xx = ((floatA*)&x)[i]; if (xx != 0.f) abort (); } return 0; } works without may_alias on __m128 for a strange reason. I'll find the patch that fixed this. -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot |dot org |org Status|UNCONFIRMED |ASSIGNED Component|c |middle-end Ever Confirmed|0 |1 Keywords| |alias, wrong-code Last reconfirmed|0000-00-00 00:00:00 |2009-05-14 11:04:20 date| | Summary|accessing aliased __m128 |[4.3 Regression] accessing |miscompiles |aliased __m128 miscompiles Target Milestone|--- |4.3.4 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40141