gcc/testsuite/gcc.c-torture/execute/pr20100-1.c

   1 /* PR tree-optimization/20100
   2    Pure function being treated as const.
   3    Author: Hans-Peter Nilsson.  */
   4
   5 static unsigned short g = 0;
   6 static unsigned short p = 0;
   7 unsigned char e;
   8
   9 static unsigned short
  10 next_g (void)
  11 {
  12   return g == e - 1 ? 0 : g + 1;
  13 }
  14
  15 static unsigned short
  16 curr_p (void)
  17 {
  18   return p;
  19 }
  20
  21 static unsigned short
  22 inc_g (void)
  23 {
  24   return g = next_g ();
  25 }
  26
  27 static unsigned short
  28 curr_g (void)
  29 {
  30   return g;
  31 }
  32
  33 static char
  34 ring_empty (void)
  35 {
  36   if (curr_p () == curr_g ())
  37     return 1;
  38   else
  39     return 0;
  40 }
  41
  42 char
  43 frob (unsigned short a, unsigned short b)
  44 {
  45   g = a;
  46   p = b;
  47   inc_g ();
  48   return ring_empty ();
  49 }
  50
  51 unsigned short
  52 get_n (void)
  53 {
  54   unsigned short n = 0;
  55   unsigned short org_g;
  56   org_g = curr_g ();
  57   while (!ring_empty () && n < 5)
  58     {
  59       inc_g ();
  60       n++;
  61     }
  62
  63   return n;
  64 }
  65
  66 void abort (void);
  67 void exit (int);
  68 int main (void)
  69 {
  70   e = 3;
  71   if (frob (0, 2) != 0 || g != 1 || p != 2 || e != 3
  72       || get_n () != 1
  73       || g != 2 || p != 2)
  74     abort ();
  75   exit (0);
  76 }