gcc/testsuite/gcc.target/i386/asm-mem.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O3" } */
   3
   4 /* Check that "m" array references are effective in preventing the
   5    array initialization from wandering past a use in the asm, and
   6    that the casts remain supported.  */
   7
   8 static int
   9 f1 (const char *p)
  10 {
  11   int count;
  12
  13   __asm__ ("repne scasb"
  14            : "=c" (count), "+D" (p)
  15            : "m" (*(const char (*)[]) p), "0" (-1), "a" (0));
  16   return -2 - count;
  17 }
  18
  19 static int
  20 f2 (const char *p)
  21 {
  22   int count;
  23
  24   __asm__ ("repne scasb"
  25            : "=c" (count), "+D" (p)
  26            : "m" (*(const char (*)[48]) p), "0" (-1), "a" (0));
  27   return -2 - count;
  28 }
  29
  30 static int
  31 f3 (int n, const char *p)
  32 {
  33   int count;
  34
  35   __asm__ ("repne scasb"
  36            : "=c" (count), "+D" (p)
  37            : "m" (*(const char (*)[n]) p), "0" (-1), "a" (0));
  38   return -2 - count;
  39 }
  40
  41 int
  42 main ()
  43 {
  44   int a;
  45   char buff[48] = "hello world";
  46   buff[4] = 0;
  47   a = f1 (buff);
  48   if (a != 4)
  49     __builtin_abort ();
  50   buff[4] = 'o';
  51   a = f2 (buff);
  52   if (a != 11)
  53     __builtin_abort ();
  54   buff[4] = 0;
  55   a = f3 (48, buff);
  56   if (a != 4)
  57     __builtin_abort ();
  58   return 0;
  59 }