Conversion of `long' and `unsigned long' to `long double' are broken
on FreeBSD/sparc64.  GCC generates the right code AFAICT, but the
implementation of _Qp_xtoq() and _Qp_uxtoq() in
/src/lib/libc/sparc64/fpu/fpu_qp.c seem to be broken.  Every value
that has bit 32 set will be negative when converted to a `long
double'.

Fix: 

Looking at the code in /usr/src/lib/libc/sparc64/fpu/fpu_qp.c (I'm
looking at revision 1.3), it seems that the _QP_TTOQ() macro only
handles 32-bit signed integers since on line 63 of that file we have:

	fe.fe_f1.fp_sign = a[0] >> 31;

I think that this line should be

	fe.fe_f1.fp_sign = a[0] >> 63;

for `long' (_Qp_xtoq) and that the line should be completely absent
for `unsigned' (_Qp_uitoq) and `unsigned long' (_Qp_uxtoq).  Some
not-too-thorough testing seems to indicate that's right.
How-To-Repeat: 
The following test program exhibits the behaviour:

#include <stdio.h>

unsigned long mant_long = 0x80000000;

int
main (void)
{
  long double mant = mant_long;
  printf ("%lu\n", mant_long);
  printf ("%Lf\n", mant);
  return 0;
}

which should print

2147483648
2147483648.000000

but will print

2147483648
-2147483648.000000