gcc/testsuite/gcc.dg/torture/pr67828.c

   1 /* Check that we don't misoptimize the final value of d.  We used to
   2    apply loop unswitching on if(j), introducing undefined behavior
   3    that the original code wouldn't exercise, and this undefined
   4    behavior would get later passes to misoptimize the loop.  */
   5
   6 /* { dg-do run } */
   7
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10
  11 int x;
  12
  13 int __attribute__ ((noinline, noclone))
  14 xprintf (int d) {
  15   if (d)
  16     {
  17       if (x)
  18         printf ("%d", d);
  19       abort ();
  20     }
  21 }
  22
  23 int a, b;
  24 short c;
  25
  26 int
  27 main ()
  28 {
  29   int j, d = 1;
  30   for (; c >= 0; c++)
  31     {
  32       a = d;
  33       d = 0;
  34       if (b)
  35         {
  36           xprintf (0);
  37           if (j)
  38             xprintf (0);
  39         }
  40     }
  41   xprintf (d);
  42   exit (0);
  43 }