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Date: Wed, 20 Jul 2005 14:21:00 -0000
From: "arndt at jjj dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20050720134633.22568.arndt@jjj.de>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug c++/22568] New: Should use cmov in some stituations
X-Bugzilla-Reason: CC
X-SW-Source: 2005-07/txt/msg02397.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

With (ulong a, ulong b) and code like
if ( a<b )  { ulong t=a; a=b; b=t; }
gcc should (if a and b are in registers already)
not emit a conditional jump but code like
MOV a, t;
CMP a, b;
CMOVcc b, a;
CMOVcc t, b;

Other such examples are easily found.  If I got it correctly, gcc
emits CMOVcc in just one situation, the conditional assignment.

Machine is AMD64, OS is SuSE Linux 9.3
gcc (GCC) 3.3.5 20050117 (prerelease) (SUSE Linux)

-- 
           Summary: Should use cmov in some stituations
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: arndt at jjj dot de
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22568