From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28190 invoked by alias); 5 Dec 2002 20:07:13 -0000 Mailing-List: contact gcc-prs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-prs-owner@gcc.gnu.org Received: (qmail 28171 invoked by uid 61); 5 Dec 2002 20:07:13 -0000 Date: Thu, 05 Dec 2002 12:07:00 -0000 Message-ID: <20021205200713.28170.qmail@sources.redhat.com> To: duchier@ps.uni-sb.de, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org From: bangerth@dealii.org Reply-To: bangerth@dealii.org, duchier@ps.uni-sb.de, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org Subject: Re: optimization/1532: -O3 generates (obviously) redundant tests and jumps X-SW-Source: 2002-12/txt/msg00296.txt.bz2 List-Id: Synopsis: -O3 generates (obviously) redundant tests and jumps State-Changed-From-To: open->analyzed State-Changed-By: bangerth State-Changed-When: Thu Dec 5 12:07:13 2002 State-Changed-Why: Confirmed. This is the relevant part of the assembler code: cmpl %eax, %edx je .L16 cmpl %eax, %edx jg .L1 movl %eax, %edx .L1: popl %ebp movl %edx, %eax ret .p2align 4,,7 .L16: leal (%eax,%eax), %edx jmp .L1 The two cmp operations are wasteful, and the one mov operation before .L1 could be merged with the one after in a better control flow. http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=1532