forked from OSchip/llvm-project
1125 lines
33 KiB
C++
1125 lines
33 KiB
C++
// RUN: %clang_cc1 -std=c++1y -verify %s -fcxx-exceptions -triple=x86_64-linux-gnu
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struct S {
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// dummy ctor to make this a literal type
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constexpr S(int);
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S();
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int arr[10];
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constexpr int &get(int n) { return arr[n]; }
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constexpr const int &get(int n) const { return arr[n]; }
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};
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S s = S();
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const S &sr = s;
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static_assert(&s.get(4) - &sr.get(2) == 2, "");
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// Compound-statements can be used in constexpr functions.
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constexpr int e() {{{{}} return 5; }}
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static_assert(e() == 5, "");
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// Types can be defined in constexpr functions.
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constexpr int f() {
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enum E { e1, e2, e3 };
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struct S {
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constexpr S(E e) : e(e) {}
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constexpr int get() { return e; }
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E e;
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};
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return S(e2).get();
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}
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static_assert(f() == 1, "");
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// Variables can be declared in constexpr functions.
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constexpr int g(int k) {
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const int n = 9;
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int k2 = k * k;
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int k3 = k2 * k;
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return 3 * k3 + 5 * k2 + n * k - 20;
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}
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static_assert(g(2) == 42, "");
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constexpr int h(int n) {
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static const int m = n; // expected-error {{static variable not permitted in a constexpr function}}
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return m;
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}
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constexpr int i(int n) {
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thread_local const int m = n; // expected-error {{thread_local variable not permitted in a constexpr function}}
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return m;
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}
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// if-statements can be used in constexpr functions.
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constexpr int j(int k) {
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if (k == 5)
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return 1;
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if (k == 1)
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return 5;
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else {
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if (int n = 2 * k - 4) {
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return n + 1;
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return 2;
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}
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}
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} // expected-note 2{{control reached end of constexpr function}}
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static_assert(j(0) == -3, "");
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static_assert(j(1) == 5, "");
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static_assert(j(2), ""); // expected-error {{constant expression}} expected-note {{in call to 'j(2)'}}
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static_assert(j(3) == 3, "");
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static_assert(j(4) == 5, "");
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static_assert(j(5) == 1, "");
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// There can be 0 return-statements.
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constexpr void k() {
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}
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// If the return type is not 'void', no return statements => never a constant
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// expression, so still diagnose that case.
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[[noreturn]] constexpr int fn() { // expected-error {{no return statement in constexpr function}}
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fn();
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}
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// We evaluate the body of a constexpr constructor, to check for side-effects.
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struct U {
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constexpr U(int n) {
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if (j(n)) {} // expected-note {{in call to 'j(2)'}}
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}
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};
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constexpr U u1{1};
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constexpr U u2{2}; // expected-error {{constant expression}} expected-note {{in call to 'U(2)'}}
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// We allow expression-statements.
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constexpr int l(bool b) {
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if (b)
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throw "invalid value for b!"; // expected-note {{subexpression not valid}}
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return 5;
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}
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static_assert(l(false) == 5, "");
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static_assert(l(true), ""); // expected-error {{constant expression}} expected-note {{in call to 'l(true)'}}
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// Potential constant expression checking is still applied where possible.
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constexpr int htonl(int x) { // expected-error {{never produces a constant expression}}
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typedef unsigned char uchar;
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uchar arr[4] = { uchar(x >> 24), uchar(x >> 16), uchar(x >> 8), uchar(x) };
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return *reinterpret_cast<int*>(arr); // expected-note {{reinterpret_cast is not allowed in a constant expression}}
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}
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constexpr int maybe_htonl(bool isBigEndian, int x) {
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if (isBigEndian)
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return x;
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typedef unsigned char uchar;
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uchar arr[4] = { uchar(x >> 24), uchar(x >> 16), uchar(x >> 8), uchar(x) };
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return *reinterpret_cast<int*>(arr); // expected-note {{reinterpret_cast is not allowed in a constant expression}}
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}
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constexpr int swapped = maybe_htonl(false, 123); // expected-error {{constant expression}} expected-note {{in call}}
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namespace NS {
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constexpr int n = 0;
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}
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constexpr int namespace_alias() {
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namespace N = NS;
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return N::n;
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}
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namespace assign {
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constexpr int a = 0;
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const int b = 0;
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int c = 0; // expected-note {{here}}
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constexpr void set(const int &a, int b) {
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const_cast<int&>(a) = b; // expected-note 3{{constant expression cannot modify an object that is visible outside that expression}}
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}
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constexpr int wrap(int a, int b) {
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set(a, b);
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return a;
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}
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static_assert((set(a, 1), a) == 1, ""); // expected-error {{constant expression}} expected-note {{in call to 'set(a, 1)'}}
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static_assert((set(b, 1), b) == 1, ""); // expected-error {{constant expression}} expected-note {{in call to 'set(b, 1)'}}
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static_assert((set(c, 1), c) == 1, ""); // expected-error {{constant expression}} expected-note {{in call to 'set(c, 1)'}}
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static_assert(wrap(a, 1) == 1, "");
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static_assert(wrap(b, 1) == 1, "");
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static_assert(wrap(c, 1) == 1, ""); // expected-error {{constant expression}} expected-note {{read of non-const variable 'c'}}
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}
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namespace string_assign {
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template<typename T>
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constexpr void swap(T &a, T &b) {
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T tmp = a;
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a = b;
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b = tmp;
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}
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template<typename Iterator>
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constexpr void reverse(Iterator begin, Iterator end) {
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while (begin != end && begin != --end)
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swap(*begin++, *end);
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}
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template<typename Iterator1, typename Iterator2>
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constexpr bool equal(Iterator1 a, Iterator1 ae, Iterator2 b, Iterator2 be) {
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while (a != ae && b != be)
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if (*a++ != *b++)
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return false;
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return a == ae && b == be;
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}
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constexpr bool test1(int n) {
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char stuff[100] = "foobarfoo";
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const char stuff2[100] = "oofraboof";
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reverse(stuff, stuff + n); // expected-note {{cannot refer to element 101 of array of 100 elements}}
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return equal(stuff, stuff + n, stuff2, stuff2 + n);
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}
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static_assert(!test1(1), "");
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static_assert(test1(3), "");
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static_assert(!test1(6), "");
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static_assert(test1(9), "");
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static_assert(!test1(100), "");
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static_assert(!test1(101), ""); // expected-error {{constant expression}} expected-note {{in call to 'test1(101)'}}
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constexpr void f() { // expected-error{{constexpr function never produces a constant expression}} expected-note@+2{{assignment to dereferenced one-past-the-end pointer is not allowed in a constant expression}}
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char foo[10] = { "z" }; // expected-note {{here}}
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foo[10] = 'x'; // expected-warning {{past the end}}
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}
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}
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namespace array_resize {
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constexpr int do_stuff(int k1, int k2) {
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int arr[1234] = { 1, 2, 3, 4 };
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arr[k1] = 5; // expected-note {{past-the-end}} expected-note {{cannot refer to element 1235}} expected-note {{cannot refer to element -1}}
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return arr[k2];
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}
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static_assert(do_stuff(1, 2) == 3, "");
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static_assert(do_stuff(0, 0) == 5, "");
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static_assert(do_stuff(1233, 1233) == 5, "");
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static_assert(do_stuff(1233, 0) == 1, "");
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static_assert(do_stuff(1234, 0) == 1, ""); // expected-error {{constant expression}} expected-note {{in call}}
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static_assert(do_stuff(1235, 0) == 1, ""); // expected-error {{constant expression}} expected-note {{in call}}
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static_assert(do_stuff(-1, 0) == 1, ""); // expected-error {{constant expression}} expected-note {{in call}}
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}
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namespace potential_const_expr {
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constexpr void set(int &n) { n = 1; }
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constexpr int div_zero_1() { int z = 0; set(z); return 100 / z; } // no error
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constexpr int div_zero_2() { // expected-error {{never produces a constant expression}}
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int z = 0;
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return 100 / (set(z), 0); // expected-note {{division by zero}}
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}
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int n; // expected-note {{declared here}}
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constexpr int ref() { // expected-error {{never produces a constant expression}}
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int &r = n;
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return r; // expected-note {{read of non-const variable 'n'}}
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}
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}
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namespace subobject {
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union A { constexpr A() : y(5) {} int x, y; };
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struct B { A a; };
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struct C : B {};
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union D { constexpr D() : c() {} constexpr D(int n) : n(n) {} C c; int n; };
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constexpr void f(D &d) {
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d.c.a.y = 3;
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// expected-note@-1 {{cannot modify an object that is visible outside}}
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// expected-note@-2 {{assignment to member 'c' of union with active member 'n'}}
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}
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constexpr bool check(D &d) { return d.c.a.y == 3; }
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constexpr bool g() { D d; f(d); return d.c.a.y == 3; }
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static_assert(g(), "");
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D d;
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constexpr bool h() { f(d); return check(d); } // expected-note {{in call}}
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static_assert(h(), ""); // expected-error {{constant expression}} expected-note {{in call}}
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constexpr bool i() { D d(0); f(d); return check(d); } // expected-note {{in call}}
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static_assert(i(), ""); // expected-error {{constant expression}} expected-note {{in call}}
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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'}}
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static_assert(j(), ""); // expected-error {{constant expression}} expected-note {{in call}}
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}
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namespace lifetime {
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constexpr int &&id(int &&n) { return static_cast<int&&>(n); }
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constexpr int &&dead() { return id(0); } // expected-note {{temporary created here}}
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constexpr int bad() { int &&n = dead(); n = 1; return n; } // expected-note {{assignment to temporary whose lifetime has ended}}
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static_assert(bad(), ""); // expected-error {{constant expression}} expected-note {{in call}}
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}
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namespace const_modify {
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constexpr int modify(int &n) { return n = 1; } // expected-note 2 {{modification of object of const-qualified type 'const int'}}
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constexpr int test1() { int k = 0; return modify(k); }
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constexpr int test2() { const int k = 0; return modify(const_cast<int&>(k)); } // expected-note 2 {{in call}}
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static_assert(test1() == 1, "");
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static_assert(test2() == 1, ""); // expected-error {{constant expression}} expected-note {{in call}}
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constexpr int i = test2(); // expected-error {{constant expression}} expected-note {{in call}}
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}
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namespace null {
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constexpr int test(int *p) {
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return *p = 123; // expected-note {{assignment to dereferenced null pointer}}
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}
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static_assert(test(0), ""); // expected-error {{constant expression}} expected-note {{in call}}
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}
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namespace incdec {
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template<typename T> constexpr T &ref(T &&r) { return r; }
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template<typename T> constexpr T postinc(T &&r) { return (r++, r); }
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template<typename T> constexpr T postdec(T &&r) { return (r--, r); }
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static_assert(++ref(0) == 1, "");
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static_assert(ref(0)++ == 0, "");
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static_assert(postinc(0) == 1, "");
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static_assert(--ref(0) == -1, "");
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static_assert(ref(0)-- == 0, "");
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static_assert(postdec(0) == -1, "");
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constexpr int overflow_int_inc_1 = ref(0x7fffffff)++; // expected-error {{constant}} expected-note {{2147483648}}
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constexpr int overflow_int_inc_1_ok = ref(0x7ffffffe)++;
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constexpr int overflow_int_inc_2 = ++ref(0x7fffffff); // expected-error {{constant}} expected-note {{2147483648}}
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constexpr int overflow_int_inc_2_ok = ++ref(0x7ffffffe);
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// inc/dec on short can't overflow because we promote to int first
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static_assert(++ref<short>(0x7fff) == (int)0xffff8000u, "");
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static_assert(--ref<short>(0x8000) == 0x7fff, "");
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// inc on bool sets to true
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static_assert(++ref(false), ""); // expected-warning {{deprecated}}
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static_assert(++ref(true), ""); // expected-warning {{deprecated}}
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int arr[10];
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static_assert(++ref(&arr[0]) == &arr[1], "");
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static_assert(++ref(&arr[9]) == &arr[10], "");
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static_assert(++ref(&arr[10]) == &arr[11], ""); // expected-error {{constant}} expected-note {{cannot refer to element 11}}
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static_assert(ref(&arr[0])++ == &arr[0], "");
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static_assert(ref(&arr[10])++ == &arr[10], ""); // expected-error {{constant}} expected-note {{cannot refer to element 11}}
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static_assert(postinc(&arr[0]) == &arr[1], "");
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static_assert(--ref(&arr[10]) == &arr[9], "");
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static_assert(--ref(&arr[1]) == &arr[0], "");
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static_assert(--ref(&arr[0]) != &arr[0], ""); // expected-error {{constant}} expected-note {{cannot refer to element -1}}
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static_assert(ref(&arr[1])-- == &arr[1], "");
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static_assert(ref(&arr[0])-- == &arr[0], ""); // expected-error {{constant}} expected-note {{cannot refer to element -1}}
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static_assert(postdec(&arr[1]) == &arr[0], "");
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int x;
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static_assert(++ref(&x) == &x + 1, "");
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static_assert(++ref(0.0) == 1.0, "");
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static_assert(ref(0.0)++ == 0.0, "");
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static_assert(postinc(0.0) == 1.0, "");
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static_assert(--ref(0.0) == -1.0, "");
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static_assert(ref(0.0)-- == 0.0, "");
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static_assert(postdec(0.0) == -1.0, "");
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static_assert(++ref(1e100) == 1e100, "");
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static_assert(--ref(1e100) == 1e100, "");
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union U {
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int a, b;
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};
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constexpr int f(U u) {
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return ++u.b; // expected-note {{increment of member 'b' of union with active member 'a'}}
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}
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constexpr int wrong_member = f({0}); // expected-error {{constant}} expected-note {{in call to 'f({.a = 0})'}}
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constexpr int vol = --ref<volatile int>(0); // expected-error {{constant}} expected-note {{decrement of volatile-qualified}}
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constexpr int incr(int k) {
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int x = k;
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if (x++ == 100)
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return x;
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return incr(x);
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}
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static_assert(incr(0) == 101, "");
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}
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namespace compound_assign {
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constexpr bool test_int() {
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int a = 3;
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a += 6;
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if (a != 9) return false;
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a -= 2;
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if (a != 7) return false;
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a *= 3;
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if (a != 21) return false;
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if (&(a /= 10) != &a) return false;
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if (a != 2) return false;
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a <<= 3;
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if (a != 16) return false;
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a %= 6;
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if (a != 4) return false;
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a >>= 1;
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if (a != 2) return false;
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a ^= 10;
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if (a != 8) return false;
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a |= 5;
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if (a != 13) return false;
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a &= 14;
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if (a != 12) return false;
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return true;
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}
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static_assert(test_int(), "");
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constexpr bool test_float() {
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float f = 123.;
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f *= 2;
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if (f != 246.) return false;
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if ((f -= 0.5) != 245.5) return false;
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if (f != 245.5) return false;
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f /= 0.5;
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if (f != 491.) return false;
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f += -40;
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if (f != 451.) return false;
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return true;
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}
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static_assert(test_float(), "");
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constexpr bool test_bool() {
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bool b = false;
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b |= 2;
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if (b != true) return false;
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b <<= 1;
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if (b != true) return false;
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b *= 2;
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if (b != true) return false;
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b -= 1;
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if (b != false) return false;
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b -= 1;
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if (b != true) return false;
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b += -1;
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if (b != false) return false;
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b += 1;
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if (b != true) return false;
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b += 1;
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if (b != true) return false;
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b ^= b;
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if (b != false) return false;
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return true;
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}
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static_assert(test_bool(), "");
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constexpr bool test_ptr() {
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int arr[123] = {};
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int *p = arr;
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if ((p += 4) != &arr[4]) return false;
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if (p != &arr[4]) return false;
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p += -1;
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if (p != &arr[3]) return false;
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if ((p -= -10) != &arr[13]) return false;
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if (p != &arr[13]) return false;
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p -= 11;
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if (p != &arr[2]) return false;
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return true;
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}
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static_assert(test_ptr(), "");
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template<typename T>
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constexpr bool test_overflow() {
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T a = 1;
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while (a != a / 2)
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a *= 2; // expected-note {{value 2147483648 is outside the range}} expected-note {{ 9223372036854775808 }} expected-note {{floating point arithmetic produces an infinity}}
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return true;
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}
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static_assert(test_overflow<int>(), ""); // expected-error {{constant}} expected-note {{call}}
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static_assert(test_overflow<unsigned>(), ""); // ok, unsigned overflow is defined
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static_assert(test_overflow<short>(), ""); // ok, short is promoted to int before multiplication
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static_assert(test_overflow<unsigned short>(), ""); // ok
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static_assert(test_overflow<unsigned long long>(), ""); // ok
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static_assert(test_overflow<long long>(), ""); // expected-error {{constant}} expected-note {{call}}
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static_assert(test_overflow<float>(), ""); // expected-error {{constant}} expected-note {{call}}
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constexpr short test_promotion(short k) {
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short s = k;
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s *= s;
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return s;
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}
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static_assert(test_promotion(100) == 10000, "");
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static_assert(test_promotion(200) == -25536, "");
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static_assert(test_promotion(256) == 0, "");
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constexpr const char *test_bounds(const char *p, int o) {
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return p += o; // expected-note {{element 5 of}} expected-note {{element -1 of}} expected-note {{element 1000 of}}
|
|
}
|
|
static_assert(test_bounds("foo", 0)[0] == 'f', "");
|
|
static_assert(test_bounds("foo", 3)[0] == 0, "");
|
|
static_assert(test_bounds("foo", 4)[-3] == 'o', "");
|
|
static_assert(test_bounds("foo" + 4, -4)[0] == 'f', "");
|
|
static_assert(test_bounds("foo", 5) != 0, ""); // expected-error {{constant}} expected-note {{call}}
|
|
static_assert(test_bounds("foo", -1) != 0, ""); // expected-error {{constant}} expected-note {{call}}
|
|
static_assert(test_bounds("foo", 1000) != 0, ""); // expected-error {{constant}} expected-note {{call}}
|
|
}
|
|
|
|
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(), "");
|
|
|
|
constexpr int range_for() {
|
|
int arr[] = { 1, 2, 3, 4, 5 };
|
|
int sum = 0;
|
|
for (int x : arr)
|
|
sum += x;
|
|
return sum;
|
|
}
|
|
static_assert(range_for() == 15, "");
|
|
|
|
template<int...N> struct ints {};
|
|
template<typename A, typename B> struct join_ints;
|
|
template<int...As, int...Bs> struct join_ints<ints<As...>, ints<Bs...>> {
|
|
using type = ints<As..., sizeof...(As) + Bs...>;
|
|
};
|
|
template<unsigned N> struct make_ints {
|
|
using type = typename join_ints<typename make_ints<N/2>::type, typename make_ints<(N+1)/2>::type>::type;
|
|
};
|
|
template<> struct make_ints<0> { using type = ints<>; };
|
|
template<> struct make_ints<1> { using type = ints<0>; };
|
|
|
|
struct ignore { template<typename ...Ts> constexpr ignore(Ts &&...) {} };
|
|
|
|
template<typename T, unsigned N> struct array {
|
|
constexpr array() : arr{} {}
|
|
template<typename ...X>
|
|
constexpr array(X ...x) : arr{} {
|
|
init(typename make_ints<sizeof...(X)>::type{}, x...);
|
|
}
|
|
template<int ...I, typename ...X> constexpr void init(ints<I...>, X ...x) {
|
|
ignore{arr[I] = x ...};
|
|
}
|
|
T arr[N];
|
|
struct iterator {
|
|
T *p;
|
|
constexpr explicit iterator(T *p) : p(p) {}
|
|
constexpr bool operator!=(iterator o) { return p != o.p; }
|
|
constexpr iterator &operator++() { ++p; return *this; }
|
|
constexpr T &operator*() { return *p; }
|
|
};
|
|
constexpr iterator begin() { return iterator(arr); }
|
|
constexpr iterator end() { return iterator(arr + N); }
|
|
};
|
|
|
|
constexpr int range_for_2() {
|
|
array<int, 5> arr { 1, 2, 3, 4, 5 };
|
|
int sum = 0;
|
|
for (int k : arr) {
|
|
sum += k;
|
|
if (sum > 8) break;
|
|
}
|
|
return sum;
|
|
}
|
|
static_assert(range_for_2() == 10, "");
|
|
}
|
|
|
|
namespace assignment_op {
|
|
struct A {
|
|
constexpr A() : n(5) {}
|
|
int n;
|
|
struct B {
|
|
int k = 1;
|
|
union U {
|
|
constexpr U() : y(4) {}
|
|
int x;
|
|
int y;
|
|
} u;
|
|
} b;
|
|
};
|
|
constexpr bool testA() {
|
|
A a, b;
|
|
a.n = 7;
|
|
a.b.u.y = 5;
|
|
b = a;
|
|
return b.n == 7 && b.b.u.y == 5 && b.b.k == 1;
|
|
}
|
|
static_assert(testA(), "");
|
|
|
|
struct B {
|
|
bool assigned = false;
|
|
constexpr B &operator=(const B&) {
|
|
assigned = true;
|
|
return *this;
|
|
}
|
|
};
|
|
struct C : B {
|
|
B b;
|
|
int n = 5;
|
|
};
|
|
constexpr bool testC() {
|
|
C c, d;
|
|
c.n = 7;
|
|
d = c;
|
|
c.n = 3;
|
|
return d.n == 7 && d.assigned && d.b.assigned;
|
|
}
|
|
static_assert(testC(), "");
|
|
}
|
|
|
|
namespace switch_stmt {
|
|
constexpr int f(char k) {
|
|
bool b = false;
|
|
int z = 6;
|
|
switch (k) {
|
|
return -1;
|
|
case 0:
|
|
if (false) {
|
|
case 1:
|
|
z = 1;
|
|
for (; b;) {
|
|
return 5;
|
|
while (0)
|
|
case 2: return 2;
|
|
case 7: z = 7;
|
|
do case 6: {
|
|
return z;
|
|
if (false)
|
|
case 3: return 3;
|
|
case 4: z = 4;
|
|
} while (1);
|
|
case 5: b = true;
|
|
case 9: z = 9;
|
|
}
|
|
return z;
|
|
} else if (false) case 8: z = 8;
|
|
else if (false) {
|
|
case 10:
|
|
z = -10;
|
|
break;
|
|
}
|
|
else z = 0;
|
|
return z;
|
|
default:
|
|
return -1;
|
|
}
|
|
return -z;
|
|
}
|
|
static_assert(f(0) == 0, "");
|
|
static_assert(f(1) == 1, "");
|
|
static_assert(f(2) == 2, "");
|
|
static_assert(f(3) == 3, "");
|
|
static_assert(f(4) == 4, "");
|
|
static_assert(f(5) == 5, "");
|
|
static_assert(f(6) == 6, "");
|
|
static_assert(f(7) == 7, "");
|
|
static_assert(f(8) == 8, "");
|
|
static_assert(f(9) == 9, "");
|
|
static_assert(f(10) == 10, "");
|
|
|
|
// Check that we can continue an outer loop from within a switch.
|
|
constexpr bool contin() {
|
|
for (int n = 0; n != 10; ++n) {
|
|
switch (n) {
|
|
case 0:
|
|
++n;
|
|
continue;
|
|
case 1:
|
|
return false;
|
|
case 2:
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
static_assert(contin(), "");
|
|
|
|
constexpr bool switch_into_for() {
|
|
int n = 0;
|
|
switch (n) {
|
|
for (; n == 1; ++n) {
|
|
return n == 1;
|
|
case 0: ;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
static_assert(switch_into_for(), "");
|
|
|
|
constexpr void duff_copy(char *a, const char *b, int n) {
|
|
switch ((n - 1) % 8 + 1) {
|
|
for ( ; n; n = (n - 1) & ~7) {
|
|
case 8: a[n-8] = b[n-8];
|
|
case 7: a[n-7] = b[n-7];
|
|
case 6: a[n-6] = b[n-6];
|
|
case 5: a[n-5] = b[n-5];
|
|
case 4: a[n-4] = b[n-4];
|
|
case 3: a[n-3] = b[n-3];
|
|
case 2: a[n-2] = b[n-2];
|
|
case 1: a[n-1] = b[n-1];
|
|
}
|
|
case 0: ;
|
|
}
|
|
}
|
|
|
|
constexpr bool test_copy(const char *str, int n) {
|
|
char buffer[16] = {};
|
|
duff_copy(buffer, str, n);
|
|
for (int i = 0; i != sizeof(buffer); ++i)
|
|
if (buffer[i] != (i < n ? str[i] : 0))
|
|
return false;
|
|
return true;
|
|
}
|
|
static_assert(test_copy("foo", 0), "");
|
|
static_assert(test_copy("foo", 1), "");
|
|
static_assert(test_copy("foo", 2), "");
|
|
static_assert(test_copy("hello world", 0), "");
|
|
static_assert(test_copy("hello world", 7), "");
|
|
static_assert(test_copy("hello world", 8), "");
|
|
static_assert(test_copy("hello world", 9), "");
|
|
static_assert(test_copy("hello world", 10), "");
|
|
static_assert(test_copy("hello world", 10), "");
|
|
}
|
|
|
|
namespace deduced_return_type {
|
|
constexpr auto f() { return 0; }
|
|
template<typename T> constexpr auto g(T t) { return t; }
|
|
static_assert(f() == 0, "");
|
|
static_assert(g(true), "");
|
|
}
|
|
|
|
namespace modify_temporary_during_construction {
|
|
struct A { int &&temporary; int x; int y; };
|
|
constexpr int f(int &r) { r *= 9; return r - 12; }
|
|
constexpr A a = { 6, f(a.temporary), a.temporary }; // expected-note {{temporary created here}}
|
|
static_assert(a.x == 42, "");
|
|
static_assert(a.y == 54, "");
|
|
constexpr int k = a.temporary++; // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}
|
|
}
|
|
|
|
namespace std {
|
|
typedef decltype(sizeof(int)) size_t;
|
|
|
|
template <class _E>
|
|
class initializer_list
|
|
{
|
|
const _E* __begin_;
|
|
size_t __size_;
|
|
|
|
constexpr initializer_list(const _E* __b, size_t __s)
|
|
: __begin_(__b),
|
|
__size_(__s)
|
|
{}
|
|
|
|
public:
|
|
typedef _E value_type;
|
|
typedef const _E& reference;
|
|
typedef const _E& const_reference;
|
|
typedef size_t size_type;
|
|
|
|
typedef const _E* iterator;
|
|
typedef const _E* const_iterator;
|
|
|
|
constexpr initializer_list() : __begin_(nullptr), __size_(0) {}
|
|
|
|
constexpr size_t size() const {return __size_;}
|
|
constexpr const _E* begin() const {return __begin_;}
|
|
constexpr const _E* end() const {return __begin_ + __size_;}
|
|
};
|
|
}
|
|
|
|
namespace InitializerList {
|
|
constexpr int sum(std::initializer_list<int> ints) {
|
|
int total = 0;
|
|
for (int n : ints) total += n;
|
|
return total;
|
|
}
|
|
static_assert(sum({1, 2, 3, 4, 5}) == 15, "");
|
|
}
|
|
|
|
namespace StmtExpr {
|
|
constexpr int f(int k) {
|
|
switch (k) {
|
|
case 0:
|
|
return 0;
|
|
|
|
({
|
|
case 1: // expected-note {{not supported}}
|
|
return 1;
|
|
});
|
|
}
|
|
}
|
|
static_assert(f(1) == 1, ""); // expected-error {{constant expression}} expected-note {{in call}}
|
|
|
|
constexpr int g() { // expected-error {{never produces a constant}}
|
|
return ({ int n; n; }); // expected-note {{object of type 'int' is not initialized}}
|
|
}
|
|
|
|
// FIXME: We should handle the void statement expression case.
|
|
constexpr int h() { // expected-error {{never produces a constant}}
|
|
({ if (true) {} }); // expected-note {{not supported}}
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
namespace VirtualFromBase {
|
|
struct S1 {
|
|
virtual int f() const;
|
|
};
|
|
struct S2 {
|
|
virtual int f();
|
|
};
|
|
template <typename T> struct X : T {
|
|
constexpr X() {}
|
|
double d = 0.0;
|
|
constexpr int f() { return sizeof(T); }
|
|
};
|
|
|
|
// Non-virtual f(), OK.
|
|
constexpr X<X<S1>> xxs1;
|
|
constexpr X<S1> *p = const_cast<X<X<S1>>*>(&xxs1);
|
|
static_assert(p->f() == sizeof(S1), "");
|
|
|
|
// Virtual f(), not OK.
|
|
constexpr X<X<S2>> xxs2;
|
|
constexpr X<S2> *q = const_cast<X<X<S2>>*>(&xxs2);
|
|
static_assert(q->f() == sizeof(X<S2>), ""); // expected-error {{constant expression}} expected-note {{virtual function call}}
|
|
}
|
|
|
|
namespace Lifetime {
|
|
constexpr int &get(int &&r) { return r; }
|
|
constexpr int f() {
|
|
int &r = get(123);
|
|
return r; // expected-note {{read of object outside its lifetime}}
|
|
}
|
|
static_assert(f() == 123, ""); // expected-error {{constant expression}} expected-note {{in call}}
|
|
|
|
constexpr int g() {
|
|
int *p = 0;
|
|
{
|
|
int n = 0;
|
|
p = &n;
|
|
n = 42;
|
|
}
|
|
*p = 123; // expected-note {{assignment to object outside its lifetime}}
|
|
return *p;
|
|
}
|
|
static_assert(g() == 42, ""); // expected-error {{constant expression}} expected-note {{in call}}
|
|
|
|
constexpr int h(int n) {
|
|
int *p[4] = {};
|
|
int &&r = 1;
|
|
p[0] = &r;
|
|
while (int a = 1) {
|
|
p[1] = &a;
|
|
for (int b = 1; int c = 1; ) {
|
|
p[2] = &b, p[3] = &c;
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
*p[n] = 0; // expected-note 3{{assignment to object outside its lifetime}}
|
|
return *p[n];
|
|
}
|
|
static_assert(h(0) == 0, ""); // ok, lifetime-extended
|
|
static_assert(h(1) == 0, ""); // expected-error {{constant expression}} expected-note {{in call}}
|
|
static_assert(h(2) == 0, ""); // expected-error {{constant expression}} expected-note {{in call}}
|
|
static_assert(h(3) == 0, ""); // expected-error {{constant expression}} expected-note {{in call}}
|
|
|
|
constexpr void lifetime_versus_loops() {
|
|
int *p = 0;
|
|
for (int i = 0; i != 2; ++i) {
|
|
int *q = p;
|
|
int n = 0;
|
|
p = &n;
|
|
if (i)
|
|
// This modifies the 'n' from the previous iteration of the loop outside
|
|
// its lifetime.
|
|
++*q; // expected-note {{increment of object outside its lifetime}}
|
|
}
|
|
}
|
|
static_assert((lifetime_versus_loops(), true), ""); // expected-error {{constant expression}} expected-note {{in call}}
|
|
}
|
|
|
|
namespace Bitfields {
|
|
struct A {
|
|
bool b : 1;
|
|
int n : 4;
|
|
unsigned u : 5;
|
|
};
|
|
constexpr bool test() {
|
|
A a {};
|
|
a.b += 2;
|
|
--a.n;
|
|
--a.u;
|
|
a.n = -a.n * 3;
|
|
return a.b == true && a.n == 3 && a.u == 31;
|
|
}
|
|
static_assert(test(), "");
|
|
}
|
|
|
|
namespace PR17615 {
|
|
struct A {
|
|
int &&r;
|
|
constexpr A(int &&r) : r(static_cast<int &&>(r)) {}
|
|
constexpr A() : A(0) {
|
|
(void)+r; // expected-note {{outside its lifetime}}
|
|
}
|
|
};
|
|
constexpr int k = A().r; // expected-error {{constant expression}} expected-note {{in call to}}
|
|
}
|
|
|
|
namespace PR17331 {
|
|
template<typename T, unsigned int N>
|
|
constexpr T sum(const T (&arr)[N]) {
|
|
T result = 0;
|
|
for (T i : arr)
|
|
result += i;
|
|
return result;
|
|
}
|
|
|
|
constexpr int ARR[] = { 1, 2, 3, 4, 5 };
|
|
static_assert(sum(ARR) == 15, "");
|
|
}
|
|
|
|
namespace EmptyClass {
|
|
struct E1 {} e1;
|
|
union E2 {} e2; // expected-note 4{{here}}
|
|
struct E3 : E1 {} e3;
|
|
|
|
template<typename E>
|
|
constexpr int f(E &a, int kind) {
|
|
switch (kind) {
|
|
case 0: { E e(a); return 0; } // expected-note {{read}} expected-note {{in call}}
|
|
case 1: { E e(static_cast<E&&>(a)); return 0; } // expected-note {{read}} expected-note {{in call}}
|
|
case 2: { E e; e = a; return 0; } // expected-note {{read}} expected-note {{in call}}
|
|
case 3: { E e; e = static_cast<E&&>(a); return 0; } // expected-note {{read}} expected-note {{in call}}
|
|
}
|
|
}
|
|
constexpr int test1 = f(e1, 0);
|
|
constexpr int test2 = f(e2, 0); // expected-error {{constant expression}} expected-note {{in call}}
|
|
constexpr int test3 = f(e3, 0);
|
|
constexpr int test4 = f(e1, 1);
|
|
constexpr int test5 = f(e2, 1); // expected-error {{constant expression}} expected-note {{in call}}
|
|
constexpr int test6 = f(e3, 1);
|
|
constexpr int test7 = f(e1, 2);
|
|
constexpr int test8 = f(e2, 2); // expected-error {{constant expression}} expected-note {{in call}}
|
|
constexpr int test9 = f(e3, 2);
|
|
constexpr int testa = f(e1, 3);
|
|
constexpr int testb = f(e2, 3); // expected-error {{constant expression}} expected-note {{in call}}
|
|
constexpr int testc = f(e3, 3);
|
|
}
|
|
|
|
namespace SpeculativeEvalWrites {
|
|
// Ensure that we don't try to speculatively evaluate writes.
|
|
constexpr int f() {
|
|
int i = 0;
|
|
int a = 0;
|
|
// __builtin_object_size speculatively evaluates its first argument.
|
|
__builtin_object_size((i = 1, &a), 0);
|
|
return i;
|
|
}
|
|
|
|
static_assert(!f(), "");
|
|
}
|
|
|
|
namespace PR27989 {
|
|
constexpr int f(int n) {
|
|
int a = (n = 1, 0);
|
|
return n;
|
|
}
|
|
static_assert(f(0) == 1, "");
|
|
}
|
|
|
|
namespace const_char {
|
|
template <int N>
|
|
constexpr int sum(const char (&Arr)[N]) {
|
|
int S = 0;
|
|
for (unsigned I = 0; I != N; ++I)
|
|
S += Arr[I]; // expected-note 2{{read of non-constexpr variable 'Cs' is not allowed}}
|
|
return S;
|
|
}
|
|
|
|
// As an extension, we support evaluating some things that are `const` as though
|
|
// they were `constexpr` when folding, but it should not be allowed in normal
|
|
// constexpr evaluation.
|
|
const char Cs[] = {'a', 'b'};
|
|
void foo() __attribute__((enable_if(sum(Cs) == 'a' + 'b', "")));
|
|
void run() { foo(); }
|
|
|
|
static_assert(sum(Cs) == 'a' + 'b', ""); // expected-error{{not an integral constant expression}} expected-note{{in call to 'sum(Cs)'}}
|
|
constexpr int S = sum(Cs); // expected-error{{must be initialized by a constant expression}} expected-note{{in call}}
|
|
}
|
|
|
|
constexpr void PR28739(int n) { // expected-error {{never produces a constant}}
|
|
int *p = &n;
|
|
p += (__int128)(unsigned long)-1; // expected-note {{cannot refer to element 18446744073709551615 of non-array object in a constant expression}}
|
|
}
|
|
|
|
constexpr void Void(int n) {
|
|
void(n + 1);
|
|
void();
|
|
}
|
|
constexpr int void_test = (Void(0), 1);
|
|
|
|
namespace PR19741 {
|
|
constexpr void addone(int &m) { m++; }
|
|
|
|
struct S {
|
|
int m = 0;
|
|
constexpr S() { addone(m); }
|
|
};
|
|
constexpr bool evalS() {
|
|
constexpr S s;
|
|
return s.m == 1;
|
|
}
|
|
static_assert(evalS(), "");
|
|
|
|
struct Nested {
|
|
struct First { int x = 42; };
|
|
union {
|
|
First first;
|
|
int second;
|
|
};
|
|
int x;
|
|
constexpr Nested(int x) : first(), x(x) { x = 4; }
|
|
constexpr Nested() : Nested(42) {
|
|
addone(first.x);
|
|
x = 3;
|
|
}
|
|
};
|
|
constexpr bool evalNested() {
|
|
constexpr Nested N;
|
|
return N.first.x == 43;
|
|
}
|
|
static_assert(evalNested(), "");
|
|
} // namespace PR19741
|
|
|
|
namespace Mutable {
|
|
struct A { mutable int n; }; // expected-note 2{{here}}
|
|
constexpr int k = A{123}.n; // ok
|
|
static_assert(k == 123, "");
|
|
|
|
struct Q { A &&a; int b = a.n; };
|
|
constexpr Q q = { A{456} }; // expected-note {{temporary}}
|
|
static_assert(q.b == 456, "");
|
|
static_assert(q.a.n == 456, ""); // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}
|
|
|
|
constexpr A a = {123};
|
|
constexpr int m = a.n; // expected-error {{constant expression}} expected-note {{mutable}}
|
|
|
|
constexpr Q r = { static_cast<A&&>(const_cast<A&>(a)) }; // expected-error {{constant expression}} expected-note@-8 {{mutable}}
|
|
|
|
struct B {
|
|
mutable int n; // expected-note {{here}}
|
|
int m;
|
|
constexpr B() : n(1), m(n) {} // ok
|
|
};
|
|
constexpr B b;
|
|
constexpr int p = b.n; // expected-error {{constant expression}} expected-note {{mutable}}
|
|
}
|
|
|
|
namespace IndirectFields {
|
|
|
|
// Reference indirect field.
|
|
struct A {
|
|
struct {
|
|
union {
|
|
int x = x = 3; // expected-note {{outside its lifetime}}
|
|
};
|
|
};
|
|
constexpr A() {}
|
|
};
|
|
static_assert(A().x == 3, ""); // expected-error{{not an integral constant expression}} expected-note{{in call to 'A()'}}
|
|
|
|
// Reference another indirect field, with different 'this'.
|
|
struct B {
|
|
struct {
|
|
union {
|
|
int x = 3;
|
|
};
|
|
int y = x;
|
|
};
|
|
constexpr B() {}
|
|
};
|
|
static_assert(B().y == 3, "");
|
|
|
|
// Nested evaluation of indirect field initializers.
|
|
struct C {
|
|
union {
|
|
int x = 1;
|
|
};
|
|
};
|
|
struct D {
|
|
struct {
|
|
C c;
|
|
int y = c.x + 1;
|
|
};
|
|
};
|
|
static_assert(D().y == 2, "");
|
|
|
|
// Explicit 'this'.
|
|
struct E {
|
|
int n = 0;
|
|
struct {
|
|
void *x = this;
|
|
};
|
|
void *y = this;
|
|
};
|
|
constexpr E e1 = E();
|
|
static_assert(e1.x != e1.y, "");
|
|
constexpr E e2 = E{0};
|
|
static_assert(e2.x != e2.y, "");
|
|
|
|
} // namespace IndirectFields
|