gcc/testsuite/gcc.dg/20050826-1.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 /* Darwin spells this differently */
   9 #ifndef MAP_ANONYMOUS
  10 #define MAP_ANONYMOUS MAP_ANON
  11 #endif
  12 #include <stdlib.h>
  13
  14     struct Flags {
  15  int filler[18];
  16  unsigned int a:14;
  17  unsigned int b:14;
  18  unsigned int c:1;
  19  unsigned int d:1;
  20  unsigned int e:1;
  21  unsigned int f:1;
  22     };
  23 static void __attribute__((noinline)) set (struct Flags *);
  24 static void set (struct Flags *fp)
  25 {
  26   fp->b = 5;
  27   fp->d = 1;
  28 }
  29
  30 static int __attribute__((noinline)) bar (int);
  31 static int bar(int x) { return !(x==1); }
  32 int main (void)
  33 {
  34   char *p = mmap (NULL, 131072, PROT_READ | PROT_WRITE,
  35                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  36   struct Flags *fp;
  37   if (p == MAP_FAILED)
  38     return 0;
  39   if (munmap (p + 65536, 65536) < 0)
  40     return 0;
  41   fp = (struct Flags*)(p + 65536 - sizeof(struct Flags));
  42   set(fp);
  43   if (fp->b > 0)
  44     return (bar(fp->d));
  45   return 1;
  46 }