math/test-fexcept-traps.c

   1 /* Test fegetexceptflag and fesetexceptflag: 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 = feraiseexcept (FE_ALL_EXCEPT);
  31   if (ret != 0)
  32     {
  33       if (EXCEPTION_TESTS (float))
  34         {
  35           puts ("feraiseexcept (FE_ALL_EXCEPT) failed");
  36           result = 1;
  37           return result;
  38         }
  39       else
  40         {
  41           puts ("feraiseexcept (FE_ALL_EXCEPT) unsupported, cannot test");
  42           return 77;
  43         }
  44     }
  45   fexcept_t saved;
  46   ret = fegetexceptflag (&saved, FE_ALL_EXCEPT);
  47   if (ret != 0)
  48     {
  49       puts ("fegetexceptflag failed");
  50       result = 1;
  51       return result;
  52     }
  53   feclearexcept (FE_ALL_EXCEPT);
  54
  55   ret = feenableexcept (FE_ALL_EXCEPT);
  56   if (!EXCEPTION_ENABLE_SUPPORTED (FE_ALL_EXCEPT) && (ret == -1))
  57     {
  58       puts ("feenableexcept (FE_ALL_EXCEPT) not supported, cannot test");
  59       return 77;
  60     }
  61   else if (ret != 0)
  62     {
  63       puts ("feenableexcept (FE_ALL_EXCEPT) failed");
  64       result = 1;
  65     }
  66
  67   /* The test is that this does not cause exception traps.  For architectures
  68      where setting the exception might result in traps the function should
  69      return a nonzero value.
  70      Also check if the function does not alter the exception mask.  */
  71   ret = fesetexceptflag (&saved, FE_ALL_EXCEPT);
  72
  73   _Static_assert (!(EXCEPTION_SET_FORCES_TRAP && !EXCEPTION_TESTS(float)),
  74                   "EXCEPTION_SET_FORCES_TRAP only makes sense if the "
  75                   "architecture suports exceptions");
  76   {
  77     int exc_before = fegetexcept ();
  78     ret = fesetexceptflag (&saved, FE_ALL_EXCEPT);
  79     int exc_after = fegetexcept ();
  80     if (exc_before != exc_after)
  81       {
  82         puts ("fesetexceptflag (FE_ALL_EXCEPT) changed the exceptions mask");
  83         return 1;
  84       }
  85   }
  86
  87   /* Execute some floating-point operations, since on some CPUs exceptions
  88      triggers a trap only at the next floating-point instruction.  */
  89   volatile double a = 1.0;
  90   volatile double b = a + a;
  91   math_force_eval (b);
  92   volatile long double al = 1.0L;
  93   volatile long double bl = al + al;
  94   math_force_eval (bl);
  95
  96   if (ret != 0 && !EXCEPTION_SET_FORCES_TRAP)
  97     {
  98       puts ("fesetexceptflag failed");
  99       result = 1;
 100     }
 101   feclearexcept (FE_ALL_EXCEPT);
 102
 103   return result;
 104 }
 105
 106 #define TEST_FUNCTION do_test ()
 107 #include "../test-skeleton.c"