gcc/testsuite/gcc.dg/torture/float128-exact-underflow.c

   1 /* Test that exact underflow in __float128 signals the underflow
   2    exception if trapping is enabled, but does not raise the flag
   3    otherwise.  */
   4
   5 /* { dg-do run { target i?86-*-*gnu* x86_64-*-*gnu* ia64-*-*gnu* } } */
   6 /* { dg-options "-D_GNU_SOURCE" } */
   7 /* { dg-require-effective-target fenv_exceptions } */
   8
   9 #include <fenv.h>
  10 #include <setjmp.h>
  11 #include <signal.h>
  12 #include <stdlib.h>
  13
  14 volatile sig_atomic_t caught_sigfpe;
  15 sigjmp_buf buf;
  16
  17 static void
  18 handle_sigfpe (int sig)
  19 {
  20   caught_sigfpe = 1;
  21   siglongjmp (buf, 1);
  22 }
  23
  24 int
  25 main (void)
  26 {
  27   volatile __float128 a = 0x1p-16382q, b = 0x1p-2q;
  28   volatile __float128 r;
  29   r = a * b;
  30   if (fetestexcept (FE_UNDERFLOW))
  31     abort ();
  32   if (r != 0x1p-16384q)
  33     abort ();
  34   feenableexcept (FE_UNDERFLOW);
  35   signal (SIGFPE, handle_sigfpe);
  36   if (sigsetjmp (buf, 1) == 0)
  37     r = a * b;
  38   if (!caught_sigfpe)
  39     abort ();
  40   exit (0);
  41 }