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Date: Sat, 19 Feb 2005 22:54:00 -0000
From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20050219165055.20083.pinskia@gcc.gnu.org>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug tree-optimization/20083] New: Missed optimization with conditional and basically ||
X-Bugzilla-Reason: CC
X-SW-Source: 2005-02/txt/msg02268.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

The following three functions should result in the same assembly (the last is the best, branchless and 
only does one compare):
int f(int i, int j, int l)
{
  int k = 0;
  if (i)
   k = 1;
  if (j)
   k = 1; 
  if (l)
    k = 1;
  return k;
}
int f1(int i, int j, int l)
{
  int k = 0;
  if (i)
   k = 1;
  else if (j)
   k = 1; 
  else if (l)
   k = 1;
  return k;
}
int f2(int i, int j, int l)
{
  return i||j||l;
}

Note I came up with this testcase after adding code like the above code to gcc and I was wondering how 
we optimizated it.

-- 
           Summary: Missed optimization with conditional and basically ||
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: tree-optimization
        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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20083