gcc/testsuite/gcc.dg/globalreg-1.c

   1 /* { dg-do run { target sparc*-*-* } } */
   2 /* { dg-options "-std=gnu99 -Os" } */
   3
   4 /* This is a massively distilled test case based upon
   5    mm/memory.c:unmap_vmas() in the Linux kernel when compiled
   6    on sparc64 for SMP which uses a global register as the
   7    base of the per-cpu variable area.
   8
   9    Because of a bug in global register handling in the dataflow
  10    code, the loop-invariant pass would move 'expression(regval)'
  11    outside of the loop.  */
  12
  13 extern void exit(int);
  14 extern void abort(void);
  15
  16 register unsigned long regval __asm__("g6");
  17
  18 extern void cond_resched(void);
  19
  20 unsigned int var;
  21
  22 static unsigned long expression(unsigned long v)
  23 {
  24   unsigned long ret;
  25
  26   __asm__("" : "=r" (ret) : "0" (0));
  27   return ret + v;
  28 }
  29
  30 void func(unsigned long *pp)
  31 {
  32   int i;
  33
  34   for (i = 0; i < 56; i++) {
  35     cond_resched();
  36     *pp = expression(regval);
  37   }
  38 }
  39
  40 void __attribute__((noinline)) cond_resched(void)
  41 {
  42         regval++;
  43 }
  44
  45 int main(void)
  46 {
  47   unsigned long val;
  48
  49   regval = 100;
  50   func(&val);
  51   if (val != 156)
  52     abort();
  53   exit(0);
  54 }