[Bug middle-end/19775] New: [3.3 regression] sqrt(pow(x,y)) != pow(x,y*0.5)

[rguenth at tat dot physik dot uni-tuebingen dot de]

This one should not abort:

#include <math.h>
#include <stdlib.h>

int main()
{
        double x = -1.0;
        if (sqrt(pow(x,2)) != 1.0)
                abort();
        return 0;
}

but both, 3.4.4 and 4.0.0 do sqrt(pow(x,y)) -> pow(x,y*0.5)
which in this case means sqrt(1.0) -> -1.0.

Ouch.

-- 
           Summary: [3.3 regression] sqrt(pow(x,y)) != pow(x,y*0.5)
           Product: gcc
           Version: 3.4.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at tat dot physik dot uni-tuebingen dot de
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19775