[Bug tree-optimization/19703] [4.0 Regression] Poor optimisation of loop test, DOM causing unsigned to int and missing combine compares

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-30 
19:20 -------
Even though DOM is the problem, IV-OPTS can be improved so we don't create the 
casts in the first 
place, patch here to do that: 
<http://gcc.gnu.org/ml/gcc-patches/2005-01/msg02209.html>.

I will try get a testcase where DOM messes up even without IV-OPTs doing 
anything.
And here is that testcase, yes it is werid for someone to do this but ...:
extern void foo6(int);
void testloop6 (void)
{
  unsigned int D1133;
  int i;
  i = 100;
  do {
    foo6 (i);
    i = ((unsigned int) i) + 4294967286U;
  }while (i != 0);
}


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19703