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* *-*-darwin* } } */
   4 /* { dg-options "-O2" } */
   5 #include <stddef.h>
   6 #include <stdio.h>
   7 #include <sys/mman.h>
   8 #ifndef MAP_ANONYMOUS
   9 #define MAP_ANONYMOUS MAP_ANON
  10 #endif
  11 #include <stdlib.h>
  12
  13 void __attribute__((noinline)) test (const char *p)
  14 {
  15   if (__builtin_strncmp (p, "abcdefghijklmnopq", 17) == 0)
  16     abort ();
  17 }
  18
  19 int main (void)
  20 {
  21   char *p = mmap (NULL, 131072, PROT_READ | PROT_WRITE,
  22                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  23   if (p == MAP_FAILED)
  24     return 0;
  25   if (munmap (p + 65536, 65536) < 0)
  26     return 0;
  27   __builtin_memcpy (p + 65536 - 5, "abcd", 5);
  28   test (p + 65536 - 5);
  29   return 0;
  30 }