From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 6053 invoked by alias); 11 Dec 2013 09:51:20 -0000 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 Received: (qmail 6024 invoked by uid 48); 11 Dec 2013 09:51:16 -0000 From: "ebotcazou at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/59461] missed zero-extension elimination in the combiner Date: Wed, 11 Dec 2013 09:51:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: rtl-optimization X-Bugzilla-Version: 4.9.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: enhancement X-Bugzilla-Who: ebotcazou at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: ebotcazou at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2013-12/txt/msg00944.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59461 --- Comment #3 from Eric Botcazou --- > I wonder if x86_64 is also affected as it has implicitely zero/sign-extending > loads as well. Not for this testcase at least, where the code is (and has always been) optimal: ee_isdigit2: .LFB0: .cfi_startproc movl %edi, %edi movzbl zeb_test_array(%rdi), %eax subl $48, %eax cmpb $9, %al setbe %al ret .cfi_endproc because the x86-64 can perform the addition in QImode directly.