| // RUN: %clang_cc1 -std=c++1y -verify %s -fcxx-exceptions -triple=x86_64-linux-gnu |
| |
| struct S { |
| // dummy ctor to make this a literal type |
| constexpr S(int); |
| |
| S(); |
| |
| int arr[10]; |
| |
| constexpr int &get(int n) { return arr[n]; } |
| constexpr const int &get(int n) const { return arr[n]; } |
| }; |
| |
| S s = S(); |
| const S &sr = s; |
| static_assert(&s.get(4) - &sr.get(2) == 2, ""); |
| |
| // Compound-statements can be used in constexpr functions. |
| constexpr int e() {{{{}} return 5; }} |
| static_assert(e() == 5, ""); |
| |
| // Types can be defined in constexpr functions. |
| constexpr int f() { |
| enum E { e1, e2, e3 }; |
| |
| struct S { |
| constexpr S(E e) : e(e) {} |
| constexpr int get() { return e; } |
| E e; |
| }; |
| |
| return S(e2).get(); |
| } |
| static_assert(f() == 1, ""); |
| |
| // Variables can be declared in constexpr functions. |
| constexpr int g(int k) { |
| const int n = 9; |
| int k2 = k * k; |
| int k3 = k2 * k; |
| return 3 * k3 + 5 * k2 + n * k - 20; |
| } |
| static_assert(g(2) == 42, ""); |
| constexpr int h(int n) { |
| static const int m = n; // expected-error {{static variable not permitted in a constexpr function}} |
| return m; |
| } |
| constexpr int i(int n) { |
| thread_local const int m = n; // expected-error {{thread_local variable not permitted in a constexpr function}} |
| return m; |
| } |
| |
| // if-statements can be used in constexpr functions. |
| constexpr int j(int k) { |
| if (k == 5) |
| return 1; |
| if (k == 1) |
| return 5; |
| else { |
| if (int n = 2 * k - 4) { |
| return n + 1; |
| return 2; |
| } |
| } |
| } // expected-note 2{{control reached end of constexpr function}} |
| static_assert(j(0) == -3, ""); |
| static_assert(j(1) == 5, ""); |
| static_assert(j(2), ""); // expected-error {{constant expression}} expected-note {{in call to 'j(2)'}} |
| static_assert(j(3) == 3, ""); |
| static_assert(j(4) == 5, ""); |
| static_assert(j(5) == 1, ""); |
| |
| // There can be 0 return-statements. |
| constexpr void k() { |
| } |
| |
| // If the return type is not 'void', no return statements => never a constant |
| // expression, so still diagnose that case. |
| [[noreturn]] constexpr int fn() { // expected-error {{no return statement in constexpr function}} |
| fn(); |
| } |
| |
| // We evaluate the body of a constexpr constructor, to check for side-effects. |
| struct U { |
| constexpr U(int n) { |
| if (j(n)) {} // expected-note {{in call to 'j(2)'}} |
| } |
| }; |
| constexpr U u1{1}; |
| constexpr U u2{2}; // expected-error {{constant expression}} expected-note {{in call to 'U(2)'}} |
| |
| // We allow expression-statements. |
| constexpr int l(bool b) { |
| if (b) |
| throw "invalid value for b!"; // expected-note {{subexpression not valid}} |
| return 5; |
| } |
| static_assert(l(false) == 5, ""); |
| static_assert(l(true), ""); // expected-error {{constant expression}} expected-note {{in call to 'l(true)'}} |
| |
| // Potential constant expression checking is still applied where possible. |
| constexpr int htonl(int x) { // expected-error {{never produces a constant expression}} |
| typedef unsigned char uchar; |
| uchar arr[4] = { uchar(x >> 24), uchar(x >> 16), uchar(x >> 8), uchar(x) }; |
| return *reinterpret_cast<int*>(arr); // expected-note {{reinterpret_cast is not allowed in a constant expression}} |
| } |
| |
| constexpr int maybe_htonl(bool isBigEndian, int x) { |
| if (isBigEndian) |
| return x; |
| |
| typedef unsigned char uchar; |
| uchar arr[4] = { uchar(x >> 24), uchar(x >> 16), uchar(x >> 8), uchar(x) }; |
| return *reinterpret_cast<int*>(arr); // expected-note {{reinterpret_cast is not allowed in a constant expression}} |
| } |
| |
| constexpr int swapped = maybe_htonl(false, 123); // expected-error {{constant expression}} expected-note {{in call}} |
| |
| namespace NS { |
| constexpr int n = 0; |
| } |
| constexpr int namespace_alias() { |
| namespace N = NS; |
| return N::n; |
| } |
| |
| namespace assign { |
| constexpr int a = 0; |
| const int b = 0; |
| int c = 0; // expected-note 2{{here}} |
| |
| constexpr void set(const int &a, int b) { |
| const_cast<int&>(a) = b; // expected-note 2{{constant expression cannot modify an object that is visible outside that expression}} |
| } |
| constexpr int wrap(int a, int b) { |
| set(a, b); |
| return a; |
| } |
| |
| static_assert((set(a, 1), a) == 1, ""); // expected-error {{constant expression}} expected-note {{in call to 'set(a, 1)'}} |
| static_assert((set(b, 1), b) == 1, ""); // expected-error {{constant expression}} expected-note {{in call to 'set(b, 1)'}} |
| static_assert((set(c, 1), c) == 1, ""); // expected-error {{constant expression}} expected-note {{read of non-const variable 'c'}} |
| |
| static_assert(wrap(a, 1) == 1, ""); |
| static_assert(wrap(b, 1) == 1, ""); |
| static_assert(wrap(c, 1) == 1, ""); // expected-error {{constant expression}} expected-note {{read of non-const variable 'c'}} |
| } |
| |
| namespace string_assign { |
| template<typename T> |
| constexpr void swap(T &a, T &b) { |
| T tmp = a; |
| a = b; |
| b = tmp; |
| } |
| template<typename Iterator> |
| constexpr void reverse(Iterator begin, Iterator end) { |
| while (begin != end && begin != --end) |
| swap(*begin++, *end); |
| } |
| template<typename Iterator1, typename Iterator2> |
| constexpr bool equal(Iterator1 a, Iterator1 ae, Iterator2 b, Iterator2 be) { |
| while (a != ae && b != be) |
| if (*a++ != *b++) |
| return false; |
| return a == ae && b == be; |
| } |
| constexpr bool test1(int n) { |
| char stuff[100] = "foobarfoo"; |
| const char stuff2[100] = "oofraboof"; |
| reverse(stuff, stuff + n); // expected-note {{cannot refer to element 101 of array of 100 elements}} |
| return equal(stuff, stuff + n, stuff2, stuff2 + n); |
| } |
| static_assert(!test1(1), ""); |
| static_assert(test1(3), ""); |
| static_assert(!test1(6), ""); |
| static_assert(test1(9), ""); |
| static_assert(!test1(100), ""); |
| static_assert(!test1(101), ""); // expected-error {{constant expression}} expected-note {{in call to 'test1(101)'}} |
| |
| // FIXME: We should be able to reject this before it's called |
| constexpr void f() { |
| char foo[10] = { "z" }; // expected-note {{here}} |
| foo[10] = 'x'; // expected-warning {{past the end}} expected-note {{assignment to dereferenced one-past-the-end pointer}} |
| } |
| constexpr int k = (f(), 0); // expected-error {{constant expression}} expected-note {{in call}} |
| } |
| |
| namespace array_resize { |
| constexpr int do_stuff(int k1, int k2) { |
| int arr[1234] = { 1, 2, 3, 4 }; |
| arr[k1] = 5; // expected-note {{past-the-end}} expected-note {{cannot refer to element 1235}} expected-note {{cannot refer to element -1}} |
| return arr[k2]; |
| } |
| static_assert(do_stuff(1, 2) == 3, ""); |
| static_assert(do_stuff(0, 0) == 5, ""); |
| static_assert(do_stuff(1233, 1233) == 5, ""); |
| static_assert(do_stuff(1233, 0) == 1, ""); |
| static_assert(do_stuff(1234, 0) == 1, ""); // expected-error {{constant expression}} expected-note {{in call}} |
| static_assert(do_stuff(1235, 0) == 1, ""); // expected-error {{constant expression}} expected-note {{in call}} |
| static_assert(do_stuff(-1, 0) == 1, ""); // expected-error {{constant expression}} expected-note {{in call}} |
| } |
| |
| namespace potential_const_expr { |
| constexpr void set(int &n) { n = 1; } |
| constexpr int div_zero_1() { int z = 0; set(z); return 100 / z; } // no error |
| constexpr int div_zero_2() { // expected-error {{never produces a constant expression}} |
| int z = 0; |
| return 100 / (set(z), 0); // expected-note {{division by zero}} |
| } |
| int n; // expected-note {{declared here}} |
| constexpr int ref() { // expected-error {{never produces a constant expression}} |
| int &r = n; |
| return r; // expected-note {{read of non-const variable 'n'}} |
| } |
| } |
| |
| namespace subobject { |
| union A { constexpr A() : y(5) {} int x, y; }; |
| struct B { A a; }; |
| struct C : B {}; |
| union D { constexpr D() : c() {} constexpr D(int n) : n(n) {} C c; int n; }; |
| constexpr void f(D &d) { |
| d.c.a.y = 3; |
| // expected-note@-1 {{cannot modify an object that is visible outside}} |
| // expected-note@-2 {{assignment to member 'c' of union with active member 'n'}} |
| } |
| constexpr bool check(D &d) { return d.c.a.y == 3; } |
| |
| constexpr bool g() { D d; f(d); return d.c.a.y == 3; } |
| static_assert(g(), ""); |
| |
| D d; |
| constexpr bool h() { f(d); return check(d); } // expected-note {{in call}} |
| static_assert(h(), ""); // expected-error {{constant expression}} expected-note {{in call}} |
| |
| constexpr bool i() { D d(0); f(d); return check(d); } // expected-note {{in call}} |
| static_assert(i(), ""); // expected-error {{constant expression}} expected-note {{in call}} |
| |
| constexpr bool j() { D d; d.c.a.x = 3; return check(d); } // expected-note {{assignment to member 'x' of union with active member 'y'}} |
| static_assert(j(), ""); // expected-error {{constant expression}} expected-note {{in call}} |
| } |
| |
| namespace lifetime { |
| constexpr int &&id(int &&n) { return static_cast<int&&>(n); } |
| constexpr int &&dead() { return id(0); } // expected-note {{temporary created here}} |
| constexpr int bad() { int &&n = dead(); n = 1; return n; } // expected-note {{assignment to temporary whose lifetime has ended}} |
| static_assert(bad(), ""); // expected-error {{constant expression}} expected-note {{in call}} |
| } |
| |
| namespace const_modify { |
| constexpr int modify(int &n) { return n = 1; } // expected-note {{modification of object of const-qualified type 'const int'}} |
| constexpr int test1() { int k = 0; return modify(k); } |
| constexpr int test2() { const int k = 0; return modify(const_cast<int&>(k)); } // expected-note {{in call}} |
| static_assert(test1() == 1, ""); |
| static_assert(test2() == 1, ""); // expected-error {{constant expression}} expected-note {{in call}} |
| } |
| |
| namespace null { |
| constexpr int test(int *p) { |
| return *p = 123; // expected-note {{assignment to dereferenced null pointer}} |
| } |
| static_assert(test(0), ""); // expected-error {{constant expression}} expected-note {{in call}} |
| } |
| |
| namespace incdec { |
| template<typename T> constexpr T &ref(T &&r) { return r; } |
| template<typename T> constexpr T postinc(T &&r) { return (r++, r); } |
| template<typename T> constexpr T postdec(T &&r) { return (r--, r); } |
| |
| static_assert(++ref(0) == 1, ""); |
| static_assert(ref(0)++ == 0, ""); |
| static_assert(postinc(0) == 1, ""); |
| static_assert(--ref(0) == -1, ""); |
| static_assert(ref(0)-- == 0, ""); |
| static_assert(postdec(0) == -1, ""); |
| |
| constexpr int overflow_int_inc_1 = ref(0x7fffffff)++; // expected-error {{constant}} expected-note {{2147483648}} |
| constexpr int overflow_int_inc_1_ok = ref(0x7ffffffe)++; |
| constexpr int overflow_int_inc_2 = ++ref(0x7fffffff); // expected-error {{constant}} expected-note {{2147483648}} |
| constexpr int overflow_int_inc_2_ok = ++ref(0x7ffffffe); |
| |
| // inc/dec on short can't overflow because we promote to int first |
| static_assert(++ref<short>(0x7fff) == (int)0xffff8000u, ""); |
| static_assert(--ref<short>(0x8000) == 0x7fff, ""); |
| |
| // inc on bool sets to true |
| static_assert(++ref(false), ""); // expected-warning {{deprecated}} |
| static_assert(++ref(true), ""); // expected-warning {{deprecated}} |
| |
| int arr[10]; |
| static_assert(++ref(&arr[0]) == &arr[1], ""); |
| static_assert(++ref(&arr[9]) == &arr[10], ""); |
| static_assert(++ref(&arr[10]) == &arr[11], ""); // expected-error {{constant}} expected-note {{cannot refer to element 11}} |
| static_assert(ref(&arr[0])++ == &arr[0], ""); |
| static_assert(ref(&arr[10])++ == &arr[10], ""); // expected-error {{constant}} expected-note {{cannot refer to element 11}} |
| static_assert(postinc(&arr[0]) == &arr[1], ""); |
| static_assert(--ref(&arr[10]) == &arr[9], ""); |
| static_assert(--ref(&arr[1]) == &arr[0], ""); |
| static_assert(--ref(&arr[0]) != &arr[0], ""); // expected-error {{constant}} expected-note {{cannot refer to element -1}} |
| static_assert(ref(&arr[1])-- == &arr[1], ""); |
| static_assert(ref(&arr[0])-- == &arr[0], ""); // expected-error {{constant}} expected-note {{cannot refer to element -1}} |
| static_assert(postdec(&arr[1]) == &arr[0], ""); |
| |
| int x; |
| static_assert(++ref(&x) == &x + 1, ""); |
| |
| static_assert(++ref(0.0) == 1.0, ""); |
| static_assert(ref(0.0)++ == 0.0, ""); |
| static_assert(postinc(0.0) == 1.0, ""); |
| static_assert(--ref(0.0) == -1.0, ""); |
| static_assert(ref(0.0)-- == 0.0, ""); |
| static_assert(postdec(0.0) == -1.0, ""); |
| |
| static_assert(++ref(1e100) == 1e100, ""); |
| static_assert(--ref(1e100) == 1e100, ""); |
| |
| union U { |
| int a, b; |
| }; |
| constexpr int f(U u) { |
| return ++u.b; // expected-note {{increment of member 'b' of union with active member 'a'}} |
| } |
| constexpr int wrong_member = f({0}); // expected-error {{constant}} expected-note {{in call to 'f({.a = 0})'}} |
| constexpr int vol = --ref<volatile int>(0); // expected-error {{constant}} expected-note {{decrement of volatile-qualified}} |
| |
| constexpr int incr(int k) { |
| int x = k; |
| if (x++ == 100) |
| return x; |
| return incr(x); |
| } |
| static_assert(incr(0) == 101, ""); |
| } |
| |
| namespace loops { |
| constexpr int fib_loop(int a) { |
| int f_k = 0, f_k_plus_one = 1; |
| for (int k = 1; k != a; ++k) { |
| int f_k_plus_two = f_k + f_k_plus_one; |
| f_k = f_k_plus_one; |
| f_k_plus_one = f_k_plus_two; |
| } |
| return f_k_plus_one; |
| } |
| static_assert(fib_loop(46) == 1836311903, ""); |
| |
| constexpr bool breaks_work() { |
| int a = 0; |
| for (int n = 0; n != 100; ++n) { |
| ++a; |
| if (a == 5) continue; |
| if ((a % 5) == 0) break; |
| } |
| |
| int b = 0; |
| while (b != 17) { |
| ++b; |
| if (b == 6) continue; |
| if ((b % 6) == 0) break; |
| } |
| |
| int c = 0; |
| do { |
| ++c; |
| if (c == 7) continue; |
| if ((c % 7) == 0) break; |
| } while (c != 21); |
| |
| return a == 10 && b == 12 & c == 14; |
| } |
| static_assert(breaks_work(), ""); |
| |
| void not_constexpr(); |
| constexpr bool no_cont_after_break() { |
| for (;;) { |
| break; |
| not_constexpr(); |
| } |
| while (true) { |
| break; |
| not_constexpr(); |
| } |
| do { |
| break; |
| not_constexpr(); |
| } while (true); |
| return true; |
| } |
| static_assert(no_cont_after_break(), ""); |
| |
| constexpr bool cond() { |
| for (int a = 1; bool b = a != 3; ++a) { |
| if (!b) |
| return false; |
| } |
| while (bool b = true) { |
| b = false; |
| break; |
| } |
| return true; |
| } |
| static_assert(cond(), ""); |
| } |