p5.cpp revision 74e1ad93fa8d6347549bcb10279fdf1fbc775321
123730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -fcxx-exceptions %s 223730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 323730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)namespace StdExample { 423730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 523730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr int f(void *) { return 0; } 623730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr int f(...) { return 1; } 7c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochconstexpr int g1() { return f(0); } 8c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochconstexpr int g2(int n) { return f(n); } 9c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochconstexpr int g3(int n) { return f(n*0); } 1023730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 11a02191e04bc25c4935f804f2c080ae28663d096dBen Murdochnamespace N { 12c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdoch constexpr int c = 5; 1323730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) constexpr int h() { return c; } 1423730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)} 1523730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr int c = 0; 1623730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr int g4() { return N::h(); } 1723730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 1823730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)static_assert(f(0) == 0, ""); 19c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochstatic_assert(f('0') == 1, ""); 20c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochstatic_assert(g1() == 0, ""); 21c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochstatic_assert(g2(0) == 1, ""); 2223730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)static_assert(g2(1) == 1, ""); 2323730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)static_assert(g3(0) == 1, ""); 2423730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)static_assert(g3(1) == 1, ""); 2523730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)static_assert(N::h() == 5, ""); 26a02191e04bc25c4935f804f2c080ae28663d096dBen Murdochstatic_assert(g4() == 5, ""); 2723730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 2823730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 2923730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr int f(bool b) 3023730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) { return b ? throw 0 : 0; } // ok 3123730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr int f() { return throw 0, 0; } // expected-error {{constexpr function never produces a constant expression}} expected-note {{subexpression}} 3223730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 3323730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)struct B { 3423730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) constexpr B(int x) : i(0) { } 3523730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) int i; 3623730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)}; 375f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 385f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)int global; // expected-note {{declared here}} 395f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 405f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)struct D : B { 415f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) constexpr D() : B(global) { } // expected-error {{constexpr constructor never produces a constant expression}} expected-note {{read of non-const}} 425f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)}; 435f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 445f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)} 455f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 465f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)namespace PotentialConstant { 475f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 485f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)constexpr int Comma(int n) { return // expected-error {{constexpr function never produces a constant expression}} 495f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) (void)(n * 2), 505f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) throw 0, // expected-note {{subexpression}} 515f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 0; 525f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)} 535f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 545f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)int ng; // expected-note 6{{here}} 555f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)constexpr int BinaryOp1(int n) { return n + ng; } // expected-error {{never produces}} expected-note {{read}} 56a02191e04bc25c4935f804f2c080ae28663d096dBen Murdochconstexpr int BinaryOp2(int n) { return ng + n; } // expected-error {{never produces}} expected-note {{read}} 57a02191e04bc25c4935f804f2c080ae28663d096dBen Murdoch 58c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochdouble dg; // expected-note 2{{here}} 59c5cede9ae108bb15f6b7a8aea21c7e1fefa2834cBen Murdochconstexpr double BinaryOp1(double d) { return d + dg; } // expected-error {{never produces}} expected-note {{read}} 6023730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr double BinaryOp2(double d) { return dg + d; } // expected-error {{never produces}} expected-note {{read}} 6123730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles) 6223730a6e56a168d1879203e4b3819bb36e3d8f1fTorne (Richard Coles)constexpr int Add(int a, int b, int c) { return a + b + c; } 63constexpr int FunctionArgs(int a) { return Add(a, ng, a); } // expected-error {{never produces}} expected-note {{read}} 64 65struct S { int a; int b; int c[2]; }; 66constexpr S InitList(int a) { return { a, ng }; }; // expected-error {{never produces}} expected-note {{read}} 67constexpr S InitList1a(int a) { return S{ a, ng }; }; // expected-error {{never produces}} expected-note {{read}} 68constexpr S InitList2(int a) { return { a, a, { ng } }; }; // expected-error {{never produces}} expected-note {{read}} 69constexpr S InitList3(int a) { return a ? S{ a, a } : S{ a, ng }; }; // ok 70 71constexpr int LogicalAnd1(int n) { return n && (throw, 0); } // ok 72constexpr int LogicalAnd2(int n) { return 1 && (throw, 0); } // expected-error {{never produces}} expected-note {{subexpression}} 73 74constexpr int LogicalOr1(int n) { return n || (throw, 0); } // ok 75constexpr int LogicalOr2(int n) { return 0 || (throw, 0); } // expected-error {{never produces}} expected-note {{subexpression}} 76 77constexpr int Conditional1(bool b, int n) { return b ? n : ng; } // ok 78constexpr 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}} 79 80// __builtin_constant_p ? : is magical, and is always a potential constant. 81constexpr bool BcpCall(int n) { 82 return __builtin_constant_p((int*)n != &n) ? (int*)n != &n : (int*)n != &n; 83} 84static_assert(BcpCall(0), ""); 85 86// DR1311: A function template which can produce a constant expression, but 87// for which a particular specialization cannot, is ok. 88template<typename T> constexpr T cmin(T a, T b) { 89 return a < b ? a : b; 90} 91int n = cmin(3, 5); // ok 92 93struct X { 94 constexpr X() {} 95 bool operator<(X); // not constexpr 96}; 97 98X x = cmin(X(), X()); // ok, not constexpr 99 100// Same with other temploids. 101template<typename T> 102struct Y { 103 constexpr Y() {} 104 constexpr int get() { return T(); } 105}; 106struct Z { operator int(); }; 107 108int y1 = Y<int>().get(); // ok 109int y2 = Y<Z>().get(); // ok 110 111} 112