From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21087 invoked by alias); 25 Aug 2007 12:39:28 -0000 Received: (qmail 19831 invoked by uid 48); 25 Aug 2007 12:39:06 -0000 Date: Sat, 25 Aug 2007 12:39:00 -0000 Message-ID: <20070825123906.19830.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug middle-end/33187] Missed cmove opportunity In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "ubizjak at gmail dot com" 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: 2007-08/txt/msg01856.txt.bz2 ------- Comment #1 from ubizjak at gmail dot com 2007-08-25 12:39 ------- There is a small problem in combine. It tries to combine insn 17 and 18, but: Failed to match this instruction: (set (reg:DF 58 [ D.1658 ]) (const_double:DF -1.0e+0 [-0x0.8p+1])) Failed to match this instruction: (set (reg:DF 58 [ D.1658 ]) (const_double:DF -1.0e+0 [-0x0.8p+1])) It looks to me, that in the second case combine "over-optimizes" the combined instruction, failing to check for: (set (reg:DF 58 [ D.1658 ]) (float_extend:DF (mem/u/c/i:SF (symbol_ref/u:SI ("*.LC2"))))) which just happens to be valid insn for i387 and as such also appropriate for ifcvt cmove transformation in the second ifcvt pass (after combine). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33187