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From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug optimization/4079] unnecessary register move on simple code
Date: Mon, 29 Mar 2004 05:32:00 -0000	[thread overview]
Message-ID: <20040329053213.7480.qmail@sources.redhat.com> (raw)
In-Reply-To: <20010822061601.4079.mattias@virtutech.se>


------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-29 05:32 -------
Using unions make the code not use a "mv" instruction:
unsigned mulh(unsigned a, unsigned b)
{
    union a{
    unsigned long long ull;
    unsigned long ul[2];
    }ullul;
    ullul.ull = ((unsigned long long)a * (unsigned long long)b);
    return ullul.ul[1];
}

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2003-11-28 07:53:38         |2004-03-29 05:32:12
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=4079


  parent reply	other threads:[~2004-03-29  5:32 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20010822061601.4079.mattias@virtutech.se>
2003-06-08 14:07 ` pinskia@physics.uc.edu
2003-08-06 16:06 ` pinskia at physics dot uc dot edu
2003-08-11 18:22 ` pinskia at gcc dot gnu dot org
2003-08-29 15:32 ` pinskia at gcc dot gnu dot org
2004-03-29  5:32 ` pinskia at gcc dot gnu dot org [this message]
2004-03-29  5:34 ` pinskia at gcc dot gnu dot org

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