clang/test/AST/ByteCode/bitfields.cpp

   1 // RUN: %clang_cc1 -fexperimental-new-constant-interpreter -Wno-bitfield-constant-conversion -verify=expected,both %s
   2 // RUN: %clang_cc1 -verify=ref,both -Wno-bitfield-constant-conversion %s
   3 // RUN: %clang_cc1 -std=c++20 -fexperimental-new-constant-interpreter -Wno-bitfield-constant-conversion -verify=expected,both %s
   4 // RUN: %clang_cc1 -std=c++20 -verify=ref,both -Wno-bitfield-constant-conversion %s
   5
   6 namespace Basic {
   7   struct A {
   8     unsigned int a : 2;
   9     constexpr A() : a(0) {}
  10     constexpr A(int a) : a(a) {}
  11   };
  12
  13   constexpr A a{1};
  14   static_assert(a.a == 1, "");
  15
  16   constexpr A a2{10};
  17   static_assert(a2.a == 2, "");
  18
  19
  20   constexpr int storeA() {
  21     A a;
  22     a.a = 10;
  23
  24     return a.a;
  25   }
  26   static_assert(storeA() == 2, "");
  27
  28   constexpr int storeA2() {
  29     A a;
  30     return a.a = 10;
  31   }
  32   static_assert(storeA2() == 2, "");
  33
  34 #if __cplusplus >= 202002
  35   struct Init1 {
  36     unsigned a : 2 = 1;
  37   };
  38   constexpr Init1 I1{};
  39   static_assert(I1.a == 1, "");
  40
  41   struct Init2 {
  42     unsigned a : 2 = 100;
  43   };
  44   constexpr Init2 I2{};
  45   static_assert(I2.a == 0, "");
  46 #endif
  47
  48   struct Init3 {
  49     unsigned a : 2;
  50     constexpr Init3() : a(100) {}
  51   };
  52   constexpr Init3 I3{};
  53   static_assert(I3.a == 0, "");
  54 }
  55
  56 namespace Overflow {
  57   struct A {int c:3;};
  58
  59   constexpr int f() {
  60     A a1{3};
  61     return a1.c++;
  62   }
  63
  64   static_assert(f() == 3, "");
  65 }
  66
  67 namespace Compound {
  68   struct A {
  69     unsigned int a : 2;
  70     constexpr A() : a(0) {}
  71     constexpr A(int a) : a(a) {}
  72   };
  73
  74   constexpr unsigned add() {
  75     A a;
  76     a.a += 10;
  77     return a.a;
  78   }
  79   static_assert(add() == 2, "");
  80
  81   constexpr unsigned sub() {
  82     A a;
  83     a.a -= 10;
  84     return a.a;
  85   }
  86   static_assert(sub() == 2, "");
  87
  88   constexpr unsigned mul() {
  89     A a(1);
  90     a.a *= 5;
  91     return a.a;
  92   }
  93   static_assert(mul() == 1, "");
  94
  95   constexpr unsigned div() {
  96     A a(2);
  97     a.a /= 2;
  98     return a.a;
  99   }
 100   static_assert(div() == 1, "");
 101 }
 102
 103 namespace test0 {
 104   extern int int_source();
 105   struct A {
 106     int aField;
 107     int bField;
 108   };
 109
 110   struct B {
 111     int onebit : 2;
 112     int twobit : 6;
 113     int intField;
 114   };
 115
 116   struct C : A, B {
 117   };
 118
 119   void b(C &c) {
 120     c.onebit = int_source();
 121   }
 122 }
 123
 124 namespace NonConstBitWidth {
 125   int n3 = 37; // both-note {{declared here}}
 126   struct S {
 127     int l : n3; // both-error {{constant expression}} \
 128                 // both-note {{read of non-const variable}}
 129   };
 130 }