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Date: Tue, 14 Jun 2005 21:19:00 -0000
From: "pthaugen at us dot ibm dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20050614211850.22067.pthaugen@us.ibm.com>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug other/22067] New: Inconsistent multiply by immediate
X-Bugzilla-Reason: CC
X-SW-Source: 2005-06/txt/msg01947.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

PR17103 states that mulli is better than decomposing into shift/add sequence.
Following is example where we are being inconsistent about that decision.

Compiled with gcc -O2 -mcpu=power4 -m32


struct S {
  int i1,i2,i3,i4,i5,i6;
}s[10];

int y;

int test1(int j, int x)
{

 y = y * 24;	// shift/sub
 s[j].i1 = 1;	// mulli

 return (x * 24);	// mulli
}

-- 
           Summary: Inconsistent multiply by immediate
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pthaugen at us dot ibm dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: powerpc64-linux
  GCC host triplet: powerpc64-linux
GCC target triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22067