[Bug tree-optimization/39506] New: PTA TBAA pruning wrong for -fargument-noalias-*

[rguenth at gcc dot gnu dot org]

int i;
int foo (int *p, int b)
{
  if (b)
    p = &i;
  i = 1;
  *p = 0;
  return i;
}

at -O2 -fargument-noalias-global shows

  # p_1 = PHI <p_3(D)(2), &i(3)>
  # i_7 = VDEF <i_6(D)>
  i = 1;
  # PARM_NOALIAS.10_9 = VDEF <PARM_NOALIAS.10_8(D)>
  *p_1 = 0;
  # VUSE <i_7>
  D.1596_5 = i;

even though *p_1 aliases i.


-- 
           Summary: PTA TBAA pruning wrong for -fargument-noalias-*
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39506