kc3-lang/gnulib/tests/test-calloc-gnu.c

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• Hash : 1e972a8a
  Author :
  Date : 2020-06-06T10:14:24
  

  calloc-gnu tests: Avoid a test failure with clang.
  
  * tests/test-calloc-gnu.c (main): Mark the pointer variable as
  'volatile', to defeat compiler optimizations.
  

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• tests/test-calloc-gnu.c

• /* Test of calloc function.
     Copyright (C) 2010-2020 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  #include <stdlib.h>
  
  /* Return 8.
     Usual compilers are not able to infer something about the return value.  */
  static unsigned int
  eight (void)
  {
    unsigned int x = rand ();
    unsigned int y = x * x * x * x;
    x++; y |= x * x * x * x;
    x++; y |= x * x * x * x;
    x++; y |= x * x * x * x;
    y = y >> 1;
    return y & -y;
  }
  
  int
  main ()
  {
    /* Check that calloc (0, 0) is not a NULL pointer.  */
    {
      void * volatile p = calloc (0, 0);
      if (p == NULL)
        return 1;
      free (p);
    }
  
    /* Check that calloc fails when requested to allocate a block of memory
       larger than SIZE_MAX bytes.
       We use eight (), not 8, to avoid a compiler warning from GCC 7.
       'volatile' is needed to defeat an incorrect optimization by clang 10,
       see <https://bugs.llvm.org/show_bug.cgi?id=46055>.  */
    {
      void * volatile p = calloc ((size_t) -1 / 8 + 1, eight ());
      if (p != NULL)
        {
          free (p);
          return 2;
        }
    }
  
    return 0;
  }
  

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