| // Copyright (C) 2018-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING3. If not see |
| // <http://www.gnu.org/licenses/>. |
| |
| // { dg-options "-std=gnu++2a" } |
| // { dg-do run { target c++2a } } |
| |
| #include <type_traits> |
| #include <testsuite_hooks.h> |
| |
| template<int N> |
| struct X { int v = N; }; |
| X<std::is_constant_evaluated()> x; // type X<true> |
| int y = 4; |
| int a = std::is_constant_evaluated() ? y : 1; // initializes a to 1 |
| int b = std::is_constant_evaluated() ? 2 : y; // initializes b to 2 |
| int c = y + (std::is_constant_evaluated() ? 2 : y); // initializes c to 2*y |
| int d = std::is_constant_evaluated(); // initializes d to 1 |
| int e = d + std::is_constant_evaluated(); // initializes e to 1 + 0 |
| |
| constexpr int |
| foo(int x) |
| { |
| const int n = std::is_constant_evaluated() ? 13 : 17; // n == 13 |
| int m = std::is_constant_evaluated() ? 13 : 17; // m might be 13 or 17 (see below) |
| char arr[n] = {}; // char[13] |
| return m + sizeof (arr) + x; |
| } |
| |
| constexpr int |
| bar() |
| { |
| const int n = std::is_constant_evaluated() ? 13 : 17; |
| X<n> x1; |
| X<std::is_constant_evaluated() ? 13 : 17> x2; |
| static_assert(std::is_same<decltype(x1), decltype(x2)>::value, |
| "x1/x2's type"); |
| return x1.v + x2.v; |
| } |
| |
| int p = foo(0); // m == 13; initialized to 26 |
| int q = p + foo(0); // m == 17 for this call; initialized to 56 |
| static_assert(bar() == 26, "bar"); |
| |
| struct S { int a, b; }; |
| |
| S s = { std::is_constant_evaluated() ? 2 : 3, y }; |
| S t = { std::is_constant_evaluated() ? 2 : 3, 4 }; |
| |
| static_assert(std::is_same<decltype(x), X<true> >::value, "x's type"); |
| |
| void |
| test01() |
| { |
| VERIFY( a == 1 && b == 2 && c == 8 && d == 1 && e == 1 && p == 26 ); |
| VERIFY( q == 56 && s.a == 3 && s.b == 4 && t.a == 2 && t.b == 4 ); |
| VERIFY( foo (y) == 34 ); |
| if constexpr (foo (0) != 26) |
| VERIFY( 0 ); |
| constexpr int w = foo (0); |
| VERIFY( w == 26 ); |
| } |
| |
| int main() |
| { |
| test01(); |
| } |