clang/test/SemaCXX/has_unique_object_reps_bitint.cpp

   1 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify -std=c++17 -Wno-bitfield-width %s
   2 //  expected-no-diagnostics
   3
   4 static_assert(__has_unique_object_representations(_BitInt(8)));
   5 static_assert(__has_unique_object_representations(unsigned _BitInt(8)));
   6 static_assert(__has_unique_object_representations(_BitInt(sizeof(int) * 8u)));
   7 // sizeof(_BitInt(24)) may be 4 to align it to the next greater integer type, in which case it would have 8 padding bits.
   8 static_assert(__has_unique_object_representations(_BitInt(24)) == (sizeof(_BitInt(24)) == 3));
   9
  10 static_assert(!__has_unique_object_representations(_BitInt(7)));
  11 static_assert(!__has_unique_object_representations(unsigned _BitInt(7)));
  12 static_assert(!__has_unique_object_representations(_BitInt(2)));
  13 static_assert(!__has_unique_object_representations(unsigned _BitInt(1)));
  14
  15 template <unsigned N>
  16 constexpr bool check() {
  17   if constexpr (N <= __BITINT_MAXWIDTH__) {
  18     static_assert(__has_unique_object_representations(_BitInt(N)) == (sizeof(_BitInt(N)) * 8u == N));
  19     static_assert(__has_unique_object_representations(unsigned _BitInt(N)) == (sizeof(unsigned _BitInt(N)) * 8u == N));
  20   }
  21   return true;
  22 }
  23
  24 template <unsigned... N>
  25 constexpr bool do_check = (check<N>() && ...);
  26
  27 static_assert(do_check<2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18>);
  28 static_assert(do_check<15, 16, 17, 23, 24, 25, 31, 32, 33>);
  29 static_assert(do_check<39, 40, 41, 47, 48, 49>);
  30 static_assert(do_check<127, 128, 129, 255, 256, 257, 383, 384, 385>);
  31
  32 template <unsigned N>
  33 struct in_struct {
  34   _BitInt(N) x;
  35   static constexpr bool check() {
  36     return __has_unique_object_representations(in_struct<N>) == __has_unique_object_representations(_BitInt(N));
  37   }
  38 };
  39
  40 static_assert(in_struct<8>::check());
  41 static_assert(in_struct<7>::check());
  42
  43 struct bit_fields_1 {
  44   _BitInt(7) x : 7;
  45   unsigned _BitInt(1) y : 1;
  46 };
  47
  48 static_assert(__has_unique_object_representations(bit_fields_1) == (sizeof(bit_fields_1) == 1));
  49
  50 struct bit_fields_2 {
  51   _BitInt(8) x : 7;
  52 };
  53
  54 static_assert(!__has_unique_object_representations(bit_fields_2));
  55
  56 struct bit_fields_3 {
  57   _BitInt(15) x : 8;
  58 };
  59
  60 static_assert(__has_unique_object_representations(bit_fields_3) == (sizeof(bit_fields_3) == 1));
  61
  62 #if __BITINT_MAXWIDTH__ >= 129
  63 struct bit_fields_4 {
  64   _BitInt(129) x : 128;
  65 };
  66
  67 static_assert(__has_unique_object_representations(bit_fields_4) == (sizeof(bit_fields_4) == 128 / 8));
  68 #endif
  69
  70 struct bit_fields_5 {
  71   _BitInt(2) x : 8;
  72 };
  73
  74 static_assert(!__has_unique_object_representations(bit_fields_5));
  75
  76 template <unsigned N>
  77 struct ref_member {
  78   _BitInt(N) & x;
  79 };
  80
  81 struct int_ref_member {
  82   int &x;
  83 };
  84
  85 static_assert(__has_unique_object_representations(ref_member<7>) == __has_unique_object_representations(ref_member<8>));
  86 static_assert(__has_unique_object_representations(ref_member<8>) == __has_unique_object_representations(int_ref_member));