[Bug middle-end/23470] New: a*a (for floats) is not considered always postive

[pinskia at gcc dot gnu dot org]

While looking into PR 23452, I noticed this:
double pow(double, double);
int f(double a, double b)
{
  if (((a*a) + (b*b))<0)
    link_error();
}

There should be no reference to link_error as a*a is always postive.  Note 
really 
__builtin_pow (a, 2.0e+0) is what is folded to first.

-- 
           Summary: a*a (for floats) is not considered always postive
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23470