1 // PR c++/67376 - [5/6 regression] Comparison with pointer to past-the-end 2 // of array fails inside constant expression 3 // This test verifies the aspect of the bug raised in comment #10, 4 // specifically comparing pointers to null. The basic regression test 5 // is in g++.dg/cpp0x/constexpr-67376.C. 6 // Note also that while the description of the bug talks about pointers 7 // pointing past the end of arrays but the prolem is more general than 8 // that and involves all constexpr object pointers. 9 10 // { dg-do compile { target c++11 } } 11 // { dg-additional-options "-Wall -Wextra -fdelete-null-pointer-checks" } 12 13 namespace A { 14 15 extern int i; 16 17 constexpr int *p0 = &i; 18 19 constexpr bool b0 = p0; // { dg-warning "address of .A::i." } 20 constexpr bool b1 = p0 == 0; // { dg-warning "address of .A::i." } 21 constexpr bool b2 = p0 != 0; // { dg-warning "address of .A::i." } 22 constexpr bool b3 = p0 < 0; // { dg-error "25:ordered comparison" } 23 constexpr bool b4 = p0 <= 0; // { dg-error "25:ordered comparison" } 24 constexpr bool b5 = p0 > 0; // { dg-error "25:ordered comparison" } 25 constexpr bool b6 = p0 >= 0; // { dg-error "25:ordered comparison" } 26 27 constexpr bool b7 = !p0; // { dg-warning "address of .A::i." } 28 constexpr bool b8 = 0 == p0; // { dg-warning "address of .A::i." } 29 constexpr bool b9 = 0 != p0; // { dg-warning "address of .A::i." } 30 constexpr bool b10 = 0 < p0; // { dg-error "24:ordered comparison" } 31 constexpr bool b11 = 0 <= p0; // { dg-error "24:ordered comparison" } 32 constexpr bool b12 = 0 > p0; // { dg-error "24:ordered comparison" } 33 constexpr bool b13 = 0 >= p0; // { dg-error "24:ordered comparison" } 34 35 } 36 37 namespace B { 38 39 // PR c++/70172 - incorrect reinterpret_cast from integer to pointer 40 // error on invalid constexpr initialization 41 42 struct S { int a, b[1]; } s; 43 44 constexpr S *p0 = &s; 45 46 constexpr int *q0 = p0->b; // { dg-bogus "reinterpret_cast from integer to pointer" } 47 48 } 49 50 namespace WeakRefTest1 { 51 52 extern __attribute__ ((weak)) int i; 53 54 constexpr int *p0 = &i; 55 56 #pragma GCC diagnostic push 57 #pragma GCC diagnostic ignored "-Wextra" 58 // Suppress warning: ordered comparison of pointer with integer zero 59 60 constexpr bool b0 = p0; // { dg-error "not a constant expression" } 61 constexpr bool b1 = p0 == 0; // { dg-error "not a constant expression" } 62 constexpr bool b2 = p0 != 0; // { dg-error "not a constant expression" } 63 constexpr bool b4 = p0 <= 0; // { dg-error "ordered comparison" } 64 constexpr bool b5 = p0 > 0; // { dg-error "ordered comparison" } 65 66 constexpr bool b7 = !p0; // { dg-error "not a constant expression" } 67 constexpr bool b8 = 0 == p0; // { dg-error "not a constant expression" } 68 constexpr bool b9 = 0 != p0; // { dg-error "not a constant expression" } 69 constexpr bool b10 = 0 < p0; // { dg-error "ordered comparison" } 70 constexpr bool b13 = 0 >= p0; // { dg-error "ordered comparison" } 71 72 constexpr bool b3 = p0 < 0; // { dg-error "ordered comparison" } 73 constexpr bool b6 = p0 >= 0; // { dg-error "ordered comparison" } 74 constexpr bool b11 = 0 <= p0; // { dg-error "ordered comparison" } 75 constexpr bool b12 = 0 > p0; // { dg-error "ordered comparison" } 76 77 #pragma GCC diagnostic pop 78 79 } 80 81 namespace WeakRefTest2 { 82 83 extern __attribute__ ((weak)) int i; 84 85 constexpr int *p1 = &i + 1; 86 87 #pragma GCC diagnostic push 88 #pragma GCC diagnostic ignored "-Wextra" 89 // Suppress warning: ordered comparison of pointer with integer zero 90 91 constexpr bool b0 = p1; // { dg-error "not a constant expression" } 92 constexpr bool b1 = p1 == 0; // { dg-error "not a constant expression" } 93 constexpr bool b2 = p1 != 0; // { dg-error "not a constant expression" } 94 constexpr bool b4 = p1 <= 0; // { dg-error "ordered comparison" } 95 constexpr bool b5 = p1 > 0; // { dg-error "ordered comparison" } 96 97 constexpr bool b7 = !p1; // { dg-error "not a constant expression" } 98 constexpr bool b8 = 0 == p1; // { dg-error "not a constant expression" } 99 constexpr bool b9 = 0 != p1; // { dg-error "not a constant expression" } 100 constexpr bool b10 = 0 < p1; // { dg-error "ordered comparison" } 101 constexpr bool b13 = 0 >= p1; // { dg-error "ordered comparison" } 102 103 // The following are accepted as constant expressions due to bug c++/70196. 104 // constexpr bool b3 = p1 < 0; 105 // constexpr bool b6 = p1 >= 0; 106 // constexpr bool b11 = 0 <= p1; 107 // constexpr bool b12 = 0 > p1; 108 109 #pragma GCC diagnostic pop 110 111 } 112