http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57675
Bug ID: 57675
Summary: Complex division of NaN by zero not handled correctly
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
Assignee: unassigned at gcc dot gnu.org
Reporter: ian at airs dot com
The rules in C99 Annex G say that if either part of a complex number is
infinity, then the whole number is treated as infinity. The rules imply but do
not clearly state that an operation involving a NaN should yield a NaN.
However, this program aborts:
__complex double f (__complex double, __complex double)
__attribute__ ((noinline));
__complex double
f (__complex double a, __complex double b)
{
return a / b;
}
int
main ()
{
__complex double c = f (__builtin_nan("") + 1.0i, 0);
if (__builtin_isinf (__real__ c) || __builtin_isinf (__imag__ c))
abort ();
exit (0);
}
Computing NaN+1.0i / 0+0i yields NaN+Inf*I. The rules of Annex G say that the
latter is infinity. But the result of dividing a NaN by 0 should be NaN, just
as the result of any operation involving NaN should be NaN.
