[Bug optimization/14705] New: [tree-ssa] more alias analysis needed!?

["kazu at cs dot umass dot edu" <gcc-bugzilla at gcc dot gnu dot org>]

The second "if" statement is not optimized away until CSE.

/* Reduced from reload_combine() in postreload.c.  */

struct s {
  int c;
  struct s *next;
};

int global;

extern void bar (void);

void
foo (struct s *p)
{
  for (; p; p = p->next)
    {
      if (p->c != 0)
	continue;

      global++;
      if (p->c == 0)
	bar ();
    }
}

To give you sense of where this comes from,
think of the first "if" as !INSN_P and
think of the second one as INSN_P with bar() being single_set_2.

-- 
           Summary: [tree-ssa] more alias analysis needed!?
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at cs dot umass dot edu
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14705