[Bug tree-optimization/30101] New: missed value numbering optimization (cprop+valnum)

[dann at godzilla dot ics dot uci dot edu]

The following 2 functions should be compiled to the same assembly. 
This is one of Briggs' compiler benchmarks.

void vnum_test12(int *data)
{
  int n;
  int stop = data[3];
  int j = data[1];
  int k = j;
  int i = 1;
  for (n=0; n<stop; n++) {
    if (j != k) i = 2;
    i = 2 - i;
    if (i != 1) k = 2;
    data[data[2]] = 2;
  }
  data[1] = i;
}
void vnum_result12(int *data)
{
  int n;
  int stop = data[3];
  for (n=0; n<stop; n++)
    data[data[2]] = 2;
  data[1] = 1;
}


-- 
           Summary: missed value numbering optimization (cprop+valnum)
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dann at godzilla dot ics dot uci dot edu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30101