clang/test/AST/ByteCode/if.cpp

   1 // RUN: %clang_cc1 -std=c++23 -fsyntax-only -fexperimental-new-constant-interpreter %s -verify=expected,both
   2 // RUN: %clang_cc1 -std=c++23 -fsyntax-only %s -verify=ref,both
   3
   4 namespace ConstEval {
   5   constexpr int f() {
   6     int i = 0;
   7     if consteval {
   8       i = 1;
   9     }
  10     return i;
  11   }
  12   static_assert(f() == 1, "");
  13
  14   constexpr int f2() {
  15     int i = 0;
  16     if !consteval {
  17         i = 12;
  18       if consteval {
  19         i = i + 1;
  20       }
  21     }
  22     return i;
  23   }
  24   static_assert(f2() == 0, "");
  25 };
  26
  27 namespace InitDecl {
  28   constexpr bool f() {
  29     if (int i = 5; i != 10) {
  30       return true;
  31     }
  32     return false;
  33   }
  34   static_assert(f(), "");
  35
  36   constexpr bool f2() {
  37     if (bool b = false; b) {
  38       return true;
  39     }
  40     return false;
  41   }
  42   static_assert(!f2(), "");
  43
  44
  45   constexpr int attrs() {
  46     if (1) [[likely]] {}
  47     return 1;
  48   }
  49   static_assert(attrs() == 1, "");
  50 };
  51
  52 /// The faulty if statement creates a RecoveryExpr with contains-errors,
  53 /// but the execution will never reach that.
  54 constexpr char g(char const (&x)[2]) {
  55     return 'x';
  56   if (auto [a, b] = x) // both-error {{an array type is not allowed here}} \
  57                        // both-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  58     ;
  59 }
  60 static_assert(g("x") == 'x');
  61
  62 namespace IfScope {
  63   struct Inc {
  64     int &a;
  65     constexpr Inc(int &a) : a(a) {}
  66     constexpr ~Inc() { ++a; }
  67   };
  68
  69   constexpr int foo() {
  70     int a= 0;
  71     int b = 12;
  72     if (Inc{a}; true) {
  73       b += a;
  74     }
  75     return b;
  76   }
  77   static_assert(foo() == 13, "");
  78 }