gcc/testsuite/gcc.dg/nrv3.c

   1 /* Verify that gimple-level NRV is occurring when values other than the
   2    return slot are call-clobbered.  */
   3 /* { dg-do compile } */
   4 /* { dg-options "-O -fdump-tree-optimized" } */
   5
   6 typedef struct { int x[20]; void *y; } S;
   7 typedef struct { int a; S b; } T;
   8 S nrv_candidate (void);
   9 void use_result (S, int);
  10 int *ptr;
  11 void foo (void)
  12 {
  13   S result;
  14   T result_arr[10][5];
  15
  16   int i;
  17
  18   ptr = &i;
  19
  20   /* i is call-clobbered for these calls, but result and result_arr
  21      aren't.  */
  22   result = nrv_candidate ();
  23   result_arr[3][4].b = nrv_candidate ();
  24
  25   use_result (result, i);
  26   use_result (result_arr[3][4].b, i);
  27 }
  28
  29 /* { dg-final { scan-tree-dump-times "return slot optimization" 2 "optimized" } } */