gcc/testsuite/gcc.target/avr/pr46779-2.c

   1 /* { dg-do run { target { ! avr_tiny } } } */
   2 /* { dg-options "-Os -fno-split-wide-types" } */
   3
   4 /* This testcase should uncover bugs like
   5    PR46779
   6    PR45291
   7    PR41894
   8
   9    The inline asm just serves to direct y into the Y register.
  10    Otherwise, it is hard to write a "stable" test case that
  11    also fails with slight variations in source code, middle- resp.
  12    backend.
  13
  14    The problem is that Y is also the frame-pointer, and
  15    avr.c:avr_hard_regno_mode_ok disallows QI to get in Y-reg.
  16    However, the y.a = 0 generates a
  17        (set (subreg:QI (reg:HI pseudo)) ...)
  18    where pseudo gets allocated to Y.
  19
  20    Reload fails to generate the right spill.
  21 */
  22
  23 #include <stdlib.h>
  24
  25 struct S
  26 {
  27     unsigned char a, b;
  28 } ab = {12, 34};
  29
  30 void yoo (struct S y)
  31 {
  32     __asm volatile ("ldi %B0, 56" : "+y" (y));
  33     y.a = 0;
  34     __asm volatile ("; y = %0" : "+y" (y));
  35     ab = y;
  36 }
  37
  38 int main ()
  39 {
  40     yoo (ab);
  41
  42     if (ab.a != 0)
  43         abort();
  44
  45     if (ab.b != 56)
  46         abort();
  47
  48     exit (0);
  49
  50     return 0;
  51 }