gcc/testsuite/gcc.dg/const-float80.c

/* Test 'w' and 'W' suffixes on __float80 type constants.  */
/* { dg-do compile { target i?86-*-* x86_64-*-* ia64-*-* } } */
/* { dg-options "" } */

__float80 a = 123.456789W;
__float80 b = 123.456789w;