gcc/testsuite/gcc.dg/20030711-1.c

   1 /* Test whether strncmp has not been "optimized" into memcmp
   2    nor any code with memcmp semantics.  */
   3 /* { dg-do run { target i?86-*-linux* x86_64-*-linux* ia64-*-linux* alpha*-*-linux* powerpc*-*-linux* s390*-*-linux* sparc*-*-linux* } } */
   4 /* { dg-options "-O2" } */
   5 #include <sys/mman.h>
   6 #include <stdlib.h>
   7
   8 void __attribute__((noinline)) test (const char *p)
   9 {
  10   if (__builtin_strncmp (p, "abcdefghijklmnopq", 17) == 0)
  11     abort ();
  12 }
  13
  14 int main (void)
  15 {
  16   char *p = mmap (NULL, 131072, PROT_READ | PROT_WRITE,
  17                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  18   if (p == MAP_FAILED)
  19     return 0;
  20   if (munmap (p + 65536, 65536) < 0)
  21     return 0;
  22   __builtin_memcpy (p + 65536 - 5, "abcd", 5);
  23   test (p + 65536 - 5);
  24   return 0;
  25 }