[Bug tree-optimization/19790] equality not noticed when signedness differs.

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2008-07-06 12:20 -------
So we can optimize

void __attribute__((noinline))
bar (int i)
{
  asm ("");
}

extern void link_error (void);
void
foo (void)
{
  int i;
  for (i = 0; i <= 320; i++)
    {
      bar (i);
      if (i > 320)
        link_error ();
    }
}

but not

void __attribute__((noinline))
bar (int i)
{
  asm ("");
}

extern void link_error (void);
void
foo (void)
{
  int i, j = 2;
  for (i = 0; i <= 320; i++)
    {
      j++;
      bar (j);
      if (j > 322)
        link_error ();
    }
}

even with the niter computation hunk restored from the PR34244 patch.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19790