From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25256 invoked by alias); 16 Jan 2012 10:16:29 -0000 Received: (qmail 25246 invoked by uid 22791); 16 Jan 2012 10:16:28 -0000 X-SWARE-Spam-Status: No, hits=-2.9 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 16 Jan 2012 10:16:16 +0000 From: "amker.cheng at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/51867] GCC generates inconsistent code for same sources calling builtin calls, like sqrtf Date: Mon, 16 Jan 2012 10:19:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Keywords: X-Bugzilla-Severity: trivial X-Bugzilla-Who: amker.cheng at gmail dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: 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: 2012-01/txt/msg01746.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51867 --- Comment #1 from amker.cheng 2012-01-16 10:15:59 UTC --- The cause is in function expand_builtin, gcc checks following conditions: ---------------------------------------------- /* When not optimizing, generate calls to library functions for a certain set of builtins. */ if (!optimize && !called_as_built_in (fndecl) && DECL_ASSEMBLER_NAME_SET_P (fndecl) && fcode != BUILT_IN_ALLOCA && fcode != BUILT_IN_ALLOCA_WITH_ALIGN && fcode != BUILT_IN_FREE) return expand_call (exp, target, ignore); The control flow is: 1, DECL_ASSEMBLER_NAME_SET_P (fndecl) is false at the first time when compiling a; 2, It is then set in following codes when expanding sqrtf call in function a; 3, When compiling function b, gcc checks DECL_ASSEMBLER_NAME_SET_P (fndecl) again and this time it's true;