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// PR c++/100995
// { dg-do compile { target c++20 } }
// { dg-options "-Wtautological-compare" }
namespace std {
constexpr inline bool
is_constant_evaluated () noexcept
{
return __builtin_is_constant_evaluated ();
}
}
template <int I = []() constexpr { if (std::is_constant_evaluated()) return 1; return 0; }()>
struct X { };
template <int I = [](){ if (std::is_constant_evaluated()) return 1; return 0; }()>
struct Y { };
template <int I = [](){ if constexpr (std::is_constant_evaluated()) return 1; return 0; }()> // { dg-warning "always evaluates to true" }
struct Z { };
constexpr bool b = true;
#define __glibcxx_assert(cond) \
if (__builtin_is_constant_evaluated() && !bool(cond)) \
__builtin_unreachable()
#define CHECK __builtin_is_constant_evaluated() // { dg-warning "always evaluates to false" }
#define CHECK2 __builtin_is_constant_evaluated()
int
foo ()
{
if (std::is_constant_evaluated ()) // { dg-warning "always evaluates to false" }
return 1;
__glibcxx_assert(b);
if (CHECK && b)
return 2;
if (CHECK2)
return 3;
return 0;
}
constexpr int
bar ()
{
if (std::is_constant_evaluated ())
return 1;
if constexpr (std::is_constant_evaluated ()) // { dg-warning "always evaluates to true" }
return 2;
if constexpr (std::is_constant_evaluated () && b) // { dg-warning "always evaluates to true" }
return 3;
if constexpr (!std::is_constant_evaluated ()) // { dg-warning "always evaluates to true" }
return 4;
return 0;
}
consteval int
baz ()
{
if (std::is_constant_evaluated ()) // { dg-warning "always evaluates to true" }
return 1;
return 0;
}
int
qux ()
{
if (({ static bool a = std::is_constant_evaluated (); a; }))
return 1;
if (({ bool a = std::is_constant_evaluated (); a; }))
return 2;
if (static bool a = std::is_constant_evaluated (); a)
return 3;
if (bool a = std::is_constant_evaluated (); a)
return 4;
if constexpr (constexpr bool a = std::is_constant_evaluated (); a)
return 5;
return 0;
}
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