sdcc/support/regression/tests/bug-221220.c

   1 /* bug-221220.c
   2    Or an approximation there of.
   3 */
   4 #include <testfwk.h>
   5
   6 typedef struct {
   7     int filler;
   8     int value;
   9 } TESTSTRUCT;
  10
  11 static void
  12 incrementValue(TESTSTRUCT *ps)
  13 {
  14     ps->value++;
  15 }
  16
  17 static void
  18 subTestStructVolatile(TESTSTRUCT *ps)
  19 {
  20     int a, b;
  21
  22     /* sdcc used to cache the value of ps->value into registers, such
  23        that as a = ps->value and b = ps->value, then a = b.  However
  24        if an intervening function uses the structure then ps->value
  25        could change.
  26     */
  27     a = ps->value;
  28     incrementValue(ps);
  29     b = ps->value;
  30
  31     ASSERT(a == 7);
  32     ASSERT(b == 8);
  33 }
  34
  35 static void
  36 testStructVolatile(void)
  37 {
  38     TESTSTRUCT s;
  39
  40     s.value = 7;
  41     subTestStructVolatile(&s);
  42 }