math/test-fesetexcept-traps.c

   1 /* Test fesetexcept: exception traps enabled.
   2    Copyright (C) 2016-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <fenv.h>
  20 #include <stdio.h>
  21 #include <math-tests.h>
  22 #include <math-barriers.h>
  23
  24 static int
  25 do_test (void)
  26 {
  27   int result = 0;
  28
  29   fedisableexcept (FE_ALL_EXCEPT);
  30   int ret = feenableexcept (FE_ALL_EXCEPT);
  31   if (!EXCEPTION_ENABLE_SUPPORTED (FE_ALL_EXCEPT) && (ret == -1))
  32     {
  33       puts ("feenableexcept (FE_ALL_EXCEPT) not supported, cannot test");
  34       return 77;
  35     }
  36   else if (ret != 0)
  37     {
  38       puts ("feenableexcept (FE_ALL_EXCEPT) failed");
  39       result = 1;
  40       return result;
  41     }
  42
  43   /* Verify fesetexcept does not cause exception traps.  For architectures
  44      where setting the exception might result in traps the function should
  45      return a nonzero value.
  46      Also check if the function does not alter the exception mask.  */
  47   ret = fesetexcept (FE_ALL_EXCEPT);
  48
  49   _Static_assert (!(EXCEPTION_SET_FORCES_TRAP && !EXCEPTION_TESTS(float)),
  50                   "EXCEPTION_SET_FORCES_TRAP only makes sense if the "
  51                   "architecture suports exceptions");
  52   {
  53     int exc_before = fegetexcept ();
  54     ret = fesetexcept (FE_ALL_EXCEPT);
  55     int exc_after = fegetexcept ();
  56     if (exc_before != exc_after)
  57       {
  58         puts ("fesetexcept (FE_ALL_EXCEPT) changed the exceptions mask");
  59         return 1;
  60       }
  61   }
  62
  63   /* Execute some floating-point operations, since on some CPUs exceptions
  64      triggers a trap only at the next floating-point instruction.  */
  65   volatile double a = 1.0;
  66   volatile double b = a + a;
  67   math_force_eval (b);
  68   volatile long double al = 1.0L;
  69   volatile long double bl = al + al;
  70   math_force_eval (bl);
  71
  72   if (ret == 0)
  73     {
  74       if (EXCEPTION_SET_FORCES_TRAP)
  75         {
  76           puts ("unexpected fesetexcept success");
  77           result = 1;
  78         }
  79     }
  80   else if (!EXCEPTION_SET_FORCES_TRAP)
  81     {
  82       puts ("fesetexcept (FE_ALL_EXCEPT) failed");
  83       if (EXCEPTION_TESTS (float))
  84         {
  85           puts ("failure of fesetexcept was unexpected");
  86           result = 1;
  87         }
  88       else
  89         puts ("failure of fesetexcept OK");
  90     }
  91   feclearexcept (FE_ALL_EXCEPT);
  92
  93   return result;
  94 }
  95
  96 #include <support/test-driver.c>