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Date: Tue, 12 Oct 2004 23:01:00 -0000
From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20041012230130.17959.pinskia@gcc.gnu.org>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug target/17959] New: -mpowerpc64 can cause worse code than without it
X-Bugzilla-Reason: CC
X-SW-Source: 2004-10/txt/msg01658.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

unsigned long long div16(unsigned long long n) { return n / 16; }

Without -mpowerpc64:
_div16:
        slwi r0,r3,28
        srwi r4,r4,4
        or r4,r0,r4
        srwi r3,r3,4
        blr

With:
_div16:
        li r0,0
        rldimi r0,r3,32,0
        rldimi r0,r4,0,32
        srdi r4,r0,4
        srdi r3,r0,36
        blr

-- 
           Summary: -mpowerpc64 can cause worse code than without it
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-darwin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17959