1// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -fcxx-exceptions %s 2// RUN: %clang_cc1 -fsyntax-only -std=c++11 -fcxx-exceptions -Wno-invalid-constexpr %s 3 4namespace StdExample { 5 6constexpr int f(void *) { return 0; } 7constexpr int f(...) { return 1; } 8constexpr int g1() { return f(0); } 9constexpr int g2(int n) { return f(n); } 10constexpr int g3(int n) { return f(n*0); } 11 12namespace N { 13 constexpr int c = 5; 14 constexpr int h() { return c; } 15} 16constexpr int c = 0; 17constexpr int g4() { return N::h(); } 18 19static_assert(f(0) == 0, ""); 20static_assert(f('0') == 1, ""); 21static_assert(g1() == 0, ""); 22static_assert(g2(0) == 1, ""); 23static_assert(g2(1) == 1, ""); 24static_assert(g3(0) == 1, ""); 25static_assert(g3(1) == 1, ""); 26static_assert(N::h() == 5, ""); 27static_assert(g4() == 5, ""); 28 29 30constexpr int f(bool b) 31 { return b ? throw 0 : 0; } // ok 32constexpr int f() { return throw 0, 0; } // expected-error {{constexpr function never produces a constant expression}} expected-note {{subexpression}} 33 34struct B { 35 constexpr B(int x) : i(0) { } 36 int i; 37}; 38 39int global; // expected-note {{declared here}} 40 41struct D : B { 42 constexpr D() : B(global) { } // expected-error {{constexpr constructor never produces a constant expression}} expected-note {{read of non-const}} 43}; 44 45} 46 47namespace PotentialConstant { 48 49constexpr int Comma(int n) { return // expected-error {{constexpr function never produces a constant expression}} 50 (void)(n * 2), 51 throw 0, // expected-note {{subexpression}} 52 0; 53} 54 55int ng; // expected-note 6{{here}} 56constexpr int BinaryOp1(int n) { return n + ng; } // expected-error {{never produces}} expected-note {{read}} 57constexpr int BinaryOp2(int n) { return ng + n; } // expected-error {{never produces}} expected-note {{read}} 58 59double dg; // expected-note 2{{here}} 60constexpr double BinaryOp1(double d) { return d + dg; } // expected-error {{never produces}} expected-note {{read}} 61constexpr double BinaryOp2(double d) { return dg + d; } // expected-error {{never produces}} expected-note {{read}} 62 63constexpr int Add(int a, int b, int c) { return a + b + c; } 64constexpr int FunctionArgs(int a) { return Add(a, ng, a); } // expected-error {{never produces}} expected-note {{read}} 65 66struct S { int a; int b; int c[2]; }; 67constexpr S InitList(int a) { return { a, ng }; }; // expected-error {{never produces}} expected-note {{read}} 68constexpr S InitList1a(int a) { return S{ a, ng }; }; // expected-error {{never produces}} expected-note {{read}} 69constexpr S InitList2(int a) { return { a, a, { ng } }; }; // expected-error {{never produces}} expected-note {{read}} 70constexpr S InitList3(int a) { return a ? S{ a, a } : S{ a, ng }; }; // ok 71 72constexpr int LogicalAnd1(int n) { return n && (throw, 0); } // ok 73constexpr int LogicalAnd2(int n) { return 1 && (throw, 0); } // expected-error {{never produces}} expected-note {{subexpression}} 74 75constexpr int LogicalOr1(int n) { return n || (throw, 0); } // ok 76constexpr int LogicalOr2(int n) { return 0 || (throw, 0); } // expected-error {{never produces}} expected-note {{subexpression}} 77 78constexpr int Conditional1(bool b, int n) { return b ? n : ng; } // ok 79constexpr int Conditional2(bool b, int n) { return b ? n * ng : n + ng; } // expected-error {{never produces}} expected-note {{both arms of conditional operator are unable to produce a constant expression}} 80 81// __builtin_constant_p ? : is magical, and is always a potential constant. 82constexpr bool BcpCall(int n) { 83 return __builtin_constant_p((int*)n != &n) ? (int*)n != &n : (int*)n != &n; 84} 85static_assert(BcpCall(0), ""); 86 87// DR1311: A function template which can produce a constant expression, but 88// for which a particular specialization cannot, is ok. 89template<typename T> constexpr T cmin(T a, T b) { 90 return a < b ? a : b; 91} 92int n = cmin(3, 5); // ok 93 94struct X { 95 constexpr X() {} 96 bool operator<(X); // not constexpr 97}; 98 99X x = cmin(X(), X()); // ok, not constexpr 100 101// Same with other temploids. 102template<typename T> 103struct Y { 104 constexpr Y() {} 105 constexpr int get() { return T(); } 106}; 107struct Z { operator int(); }; 108 109int y1 = Y<int>().get(); // ok 110int y2 = Y<Z>().get(); // ok 111 112} 113