Description:
------------
void *
__gmp_default_reallocate (void *oldptr, size_t old_size, size_t new_size)
{
  void *ret;

#ifdef DEBUG
  size_t req_size = new_size;

  if (old_size != 0)
    {
      mp_ptr p = oldptr;
      if (p[-1] != (0xdeadbeef << 31) + 0xdeafdeed)
	{
	  fprintf (stderr, "gmp: (realloc) data clobbered before allocation block\n");
	  abort ();
	}
      if (old_size % BYTES_PER_MP_LIMB == 0)
	if (p[old_size / BYTES_PER_MP_LIMB] != ~((0xdeadbeef << 31) + 0xdeafdeed))
	  {
	    fprintf (stderr, "gmp: (realloc) data clobbered after allocation block\n");
	    abort ();
	  }
      oldptr = p - 1;
    }

  new_size += 2 * BYTES_PER_MP_LIMB;
#endif

  ret = realloc (oldptr, new_size);
  if (ret == 0)
    {
#if defined _MSC_VER && defined _WIN64
        fprintf (stderr, "GNU MP: Cannot reallocate memory (old_size=%llu new_size=%llu)\n", old_size, new_size);
#else
        fprintf (stderr, "GNU MP: Cannot reallocate memory (old_size=%lu new_size=%lu)\n", old_size, new_size);
#endif
      abort ();
    }


This abort inside __gmp_default_reallocate is reached with the attached test scripts. Maybe a check can be implemented inside php-gmp extension to prevent it. Tested on 64 bits Windows.

Test script:
---------------
<?php

$v1=-4500000000;
echo gmp_random($v1); 
 
<?php
$v1=PHP_INT_MAX;
gmp_random_bits($v1); 

Expected result:
----------------
No crash

Actual result:
--------------
php.exe crashes