[Bug middle-end/30322] ((-i-1) + i) +1) is turned into ~i + (i+1) and never into 0 on the tree level

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2007-01-05 16:30 -------
It seems to be IVOPTs rewriting introduces the trees.  Testcase:

extern void op( int, int);
void foo(int f0, int f1, int e0, int e1)
{
  for (int i1 = f1; i1 <= e1; ++i1)
    for (int i0 = f0; i0 <= e0; ++i0)
      op(i0, i1);
}

results in (./cc1plus -O2):

void foo(int, int, int, int) (f0, f1, e0, e1)
{
  int i0;
  int i1;

<bb 2>:
  if (f1 <= e1) goto <L26>; else goto <L5>;

<L26>:;
  i1 = f1;
  goto <bb 5> (<L2>);

<L25>:;
  i0 = f0;

<L1>:;
  op (i0, i1);
  i0 = i0 + 1;
  if (e0 >= i0) goto <L1>; else goto <L3>;

<L3>:;
  i1 = i1 + 1;
  if (i1 != (int) ((unsigned int) f1 + 2 + (unsigned int) ~f1 + (unsigned int)
e1)) goto <L2>; else goto <L5>;

<L2>:;
  if (f0 <= e0) goto <L25>; else goto <L3>;

<L5>:;
  return;

}


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rakdver at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30322