RFA: don't try to compare IEEE NaN's
Jim Blandy
jimb@zwingli.cygnus.com
Tue Jun 5 20:40:00 GMT 2001
2001-06-05 Jim Blandy <jimb@redhat.com>
* gdb.base/return2.exp (main): Use values to test float and double
returns that are not NaN's, to avoid being confused by IEEE
comparison rules.
Index: gdb/testsuite/gdb.base/return2.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/testsuite/gdb.base/return2.c,v
retrieving revision 1.2
diff -c -r1.2 return2.c
*** gdb/testsuite/gdb.base/return2.c 2000/12/20 14:34:27 1.2
--- gdb/testsuite/gdb.base/return2.c 2001/06/06 03:39:25
***************
*** 84,91 ****
int_resultval = int_func (); /* short_checkpoint */
long_resultval = long_func (); /* int_checkpoint */
long_long_resultval = long_long_func (); /* long_checkpoint */
! float_resultval = float_func (); /* long_long_checkpoint */
! double_resultval = double_func (); /* float_checkpoint */
main_test = 1; /* double_checkpoint */
return 0;
}
--- 84,110 ----
int_resultval = int_func (); /* short_checkpoint */
long_resultval = long_func (); /* int_checkpoint */
long_long_resultval = long_long_func (); /* long_checkpoint */
!
! /* On machines using IEEE floating point, the test pattern of all
! 1-bits established above turns out to be a floating-point NaN
! ("Not a Number"). According to the IEEE rules, NaN's aren't even
! equal to themselves. This can lead to stupid conversations with
! GDB like:
!
! (gdb) p testval.float_testval == testval.float_testval
! $7 = 0
! (gdb)
!
! This is the correct answer, but it's not the sort of thing
! return2.exp wants to see. So to make things work the way they
! ought, we'll set aside the `union' cleverness and initialize the
! test values explicitly here. These values have interesting bits
! throughout the value, so we'll still detect truncated values. */
!
! testval.float_testval = 2.7182818284590452354;/* long_long_checkpoint */
! float_resultval = float_func ();
! testval.double_testval = 3.14159265358979323846; /* float_checkpoint */
! double_resultval = double_func ();
main_test = 1; /* double_checkpoint */
return 0;
}
More information about the Gdb-patches
mailing list