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 mmap } } */
   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 #ifndef MAP_ANON
  13 #define MAP_ANON 0
  14 #endif
  15 #include <stdlib.h>
  16
  17     struct Flags {
  18  int filler[18];
  19  unsigned int a:14;
  20  unsigned int b:14;
  21  unsigned int c:1;
  22  unsigned int d:1;
  23  unsigned int e:1;
  24  unsigned int f:1;
  25     };
  26 static void __attribute__((noinline)) set (struct Flags *);
  27 static void set (struct Flags *fp)
  28 {
  29   fp->b = 5;
  30   fp->d = 1;
  31 }
  32
  33 static int __attribute__((noinline)) bar (int);
  34 static int bar(int x) { return !(x==1); }
  35 int main (void)
  36 {
  37   char *p = mmap (NULL, 131072, PROT_READ | PROT_WRITE,
  38                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  39   struct Flags *fp;
  40   if (p == MAP_FAILED)
  41     return 0;
  42   if (munmap (p + 65536, 65536) < 0)
  43     return 0;
  44   fp = (struct Flags*)(p + 65536 - sizeof(struct Flags));
  45   set(fp);
  46   if (fp->b > 0)
  47     return (bar(fp->d));
  48   return 1;
  49 }