gcc/testsuite/gcc.dg/fixed-point/struct-union.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O -Wall" } */
   3
   4 /* C99 6.5.2.3 Structure and union members.
   5    If the first expression has qualified type, the result has the so-qualified
   6    version of the type of the designated member.
   7    Based on the test from ../dfp/.  */
   8
   9 struct s {_Fract f; const long _Fract lf;};
  10 struct sv { volatile _Fract f; volatile long _Fract lf; };
  11 union u
  12 {
  13   const long _Fract lf;
  14   _Fract f;
  15   const struct s cs;
  16 };
  17
  18 struct s s;
  19 struct sv sv;
  20 const struct s cs;
  21
  22 union u u;
  23 const union u cu;
  24
  25 struct s g (struct s s)
  26 {
  27   return s;
  28 }
  29
  30 union u h (union u u)
  31 {
  32   return u;
  33 }
  34
  35 void f()
  36 {
  37   cs.f = 0.1r; /* { dg-error "assignment of read-only variable" } */
  38   cs.lf = 0.2lr; /* { dg-error "assignment of read-only variable" } */
  39   s.lf = 0.3lr;  /* { dg-error "assignment of read-only member" } */
  40
  41   s.f = 0.4r;
  42   u.f = 0.5r;
  43
  44   u.lf = 0.6lr;    /* { dg-error "assignment of read-only member" } */
  45   u.cs.f = 0.7r; /* { dg-error "assignment of read-only member" } */
  46   u.cs.lf = 0.8lr; /* { dg-error "assignment of read-only member" } */
  47
  48   cu.f = 0.9r;   /* { dg-error "assignment of read-only variable" } */
  49
  50   cu.lf = 0.01lr;    /* { dg-error "assignment of read-only variable" } */
  51   cu.cs.f = 0.02r; /* { dg-error "assignment of read-only variable" } */
  52   cu.cs.lf = 0.03lr; /* { dg-error "assignment of read-only variable" } */
  53
  54   /* f().x is a valid postfix expression but is not an lvalue if
  55      function f() returning a structure or union.  */
  56   g(s).f = 0.04r;  /* { dg-error "lvalue required" } */
  57   h(u).lf = 0.05lr;  /* { dg-error "lvalue required" } */
  58
  59   /* Test assignment to volatile structure members.  */
  60   sv.f = 0.06r;
  61   sv.lf = 0.07lr;
  62 }
  63