[clang] [C23] Implement N3018: The constexpr specifier for object definitions (PR #73099)
Mariya Podchishchaeva via cfe-commits
cfe-commits at lists.llvm.org
Mon Feb 26 09:12:08 PST 2024
================
@@ -0,0 +1,296 @@
+// RUN: %clang_cc1 -std=c2x -verify -triple x86_64 -pedantic -Wno-conversion -Wno-constant-conversion -Wno-div-by-zero %s
+
+// Check that constexpr only applies to variables.
+constexpr void f0() {} // expected-error {{'constexpr' can only be used in variable declarations}}
+constexpr const int f1() { return 0; } // expected-error {{'constexpr' can only be used in variable declarations}}
+
+constexpr struct S1 { int f; }; //expected-error {{struct cannot be marked constexpr}}
+constexpr struct S2 ; // expected-error {{struct cannot be marked constexpr}}
+constexpr union U1; // expected-error {{union cannot be marked constexpr}}
+constexpr union U2 {int a; float b;}; // expected-error {{union cannot be marked constexpr}}
+constexpr enum E1 {A = 1, B = 2} ; // expected-error {{enum cannot be marked constexpr}}
+struct S3 {
+ static constexpr int f = 0; // expected-error {{type name does not allow storage class}}
+ // expected-error at -1 {{type name does not allow constexpr}}
+ // expected-error at -2 {{expected ';' at end}}
+ constexpr int f1 = 0;
+ // expected-error at -1 {{type name does not allow constexpr}}
+ // expected-error at -2 {{expected ';' at end}}
+};
+
+constexpr; // expected-error {{'constexpr' can only be used in variable declarations}}
+constexpr int V1 = 3;
+constexpr float V2 = 7.0;
+int V3 = (constexpr)3; // expected-error {{expected expression}}
+
+void f2() {
+ constexpr int a = 0;
+ constexpr float b = 1.7f;
+}
+
+// Check how constexpr works with other storage-class specifiers.
+constexpr auto V4 = 1;
+constexpr static auto V5 = 1;
+constexpr static const auto V6 = 1;
+constexpr static const int V7 = 1;
+constexpr static int V8 = 1;
+constexpr auto Ulong = 1L;
+constexpr auto CompoundLiteral = (int){13};
+constexpr auto DoubleCast = (double)(1 / 3);
+constexpr auto String = "this is a string";
+constexpr signed auto Long = 1L; // expected-error {{'auto' cannot be signed or unsigned}}
+_Static_assert(_Generic(Ulong, long : 1));
+_Static_assert(_Generic(CompoundLiteral, int : 1));
+_Static_assert(_Generic(DoubleCast, double : 1));
+_Static_assert(_Generic(String, char* : 1));
+
+void f3(constexpr register int P1) { // expected-error {{function parameter cannot be constexpr}}
+ constexpr register int V9 = 0;
+ constexpr register auto V10 = 0.0;
+}
+
+constexpr thread_local int V11 = 38; // expected-error {{cannot combine with previous '_Thread_local' declaration specifier}}
+constexpr static thread_local double V12 = 38; // expected-error {{cannot combine with previous '_Thread_local' declaration specifier}}
+constexpr extern thread_local char V13; // expected-error {{cannot combine with previous '_Thread_local' declaration specifier}}
+// expected-error at -1 {{cannot combine with previous 'extern' declaration specifier}}
+// expected-error at -2 {{constexpr variable declaration must be a definition}}
+constexpr thread_local short V14 = 38; // expected-error {{cannot combine with previous '_Thread_local' declaration specifier}}
+
+// Check how constexpr works with qualifiers.
+constexpr _Atomic int V15 = 0; // expected-error {{constexpr variable cannot have type 'const _Atomic(int)'}}
+constexpr _Atomic(int) V16 = 0; // expected-error {{constexpr variable cannot have type 'const _Atomic(int)'}}
+
+constexpr volatile int V17 = 0; // expected-error {{constexpr variable cannot have type 'const volatile int'}}
+
+constexpr int * restrict V18 = 0; // expected-error {{constexpr variable cannot have type 'int *const restrict'}}
+
+typedef _Atomic(int) TheA;
+typedef volatile short TheV;
+typedef float * restrict TheR;
+
+constexpr TheA V19[3] = {};
+// expected-error at -1 {{constexpr variable cannot have type 'const TheA' (aka 'const _Atomic(int)')}}
+constexpr TheV V20[3] = {};
+// expected-error at -1 {{constexpr variable cannot have type 'const TheV' (aka 'const volatile short')}}
+constexpr TheR V21[3] = {};
+// expected-error at -1 {{constexpr variable cannot have type 'const TheR' (aka 'float *const restrict')}}
+
+struct HasA {
+ TheA f;
+ int b;
+};
+
+struct HasV {
+ float b;
+ TheV f;
+};
+
+struct HasR {
+ short b;
+ int a;
+ TheR f;
+};
+
+constexpr struct HasA V22[2] = {};
+// expected-error at -1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
+constexpr struct HasV V23[2] = {};
+// expected-error at -1 {{constexpr variable cannot have type 'TheV' (aka 'volatile short')}}
+constexpr struct HasR V24[2] = {};
+// expected-error at -1 {{constexpr variable cannot have type 'TheR' (aka 'float *restrict')}}
+
+union U3 {
+ float a;
+ union {
+ struct HasA f;
+ struct HasR f1;
+ };
+};
+
+constexpr union U3 V25 = {};
+// expected-error at -1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
+constexpr union U3 V26[8] = {};
+// expected-error at -1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
+
+struct S4 {
+ union U3 f[3];
+};
+
+constexpr struct S4 V27 = {};
+// expected-error at -1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
+constexpr const int V28 = 28;
+
+// Check that constexpr variable must have a valid initializer which is a
+// constant expression.
+constexpr int V29;
+// expected-error at -1 {{constexpr variable 'V29' must be initialized by a constant expression}}
+
+struct S5 {
+ int f;
+};
+
+constexpr struct S5 V30;
+// expected-error at -1 {{constexpr variable 'V30' must be initialized by a constant expression}}
+constexpr struct S5 V31 = {};
+
+int randomFoo() { return 7; }
+
+constexpr float V32 = randomFoo();
+// expected-error at -1 {{constexpr variable 'V32' must be initialized by a constant expression}}
+
+const int V33 = 4;
+const int V34 = 0;
+const int V35 = 2;
+
+constexpr int V36 = V33 / V34;
+// expected-error at -1 {{constexpr variable 'V36' must be initialized by a constant expression}}
+constexpr int V37 = V33 / V35;
+// expected-error at -1 {{constexpr variable 'V37' must be initialized by a constant expression}}
+constexpr int V38 = 3;
+constexpr int V39 = V38 / V38;
+constexpr int V40 = V38 / 2;
+constexpr int V41 = V38 / 0;
+// expected-error at -1 {{constexpr variable 'V41' must be initialized by a constant expression}}
+// expected-note at -2 {{division by zero}}
+constexpr int V42 = V38 & 0;
+
+constexpr struct S5 V43 = { randomFoo() };
+// expected-error at -1 {{constexpr variable 'V43' must be initialized by a constant expression}}
+constexpr struct S5 V44 = { 0 };
+constexpr struct S5 V45 = { V38 / 0 };
+// expected-error at -1 {{constexpr variable 'V45' must be initialized by a constant expression}}
+// expected-note at -2 {{division by zero}}
+
+constexpr float V46[3] = {randomFoo() };
+// expected-error at -1 {{constexpr variable 'V46' must be initialized by a constant expression}}
+constexpr struct S5 V47[3] = {randomFoo() };
+// expected-error at -1 {{constexpr variable 'V47' must be initialized by a constant expression}}
+
+const static int V48 = V38;
+constexpr static int V49 = V48;
+// expected-error at -1 {{constexpr variable 'V49' must be initialized by a constant expression}}
+
+void f4(const int P1) {
+ constexpr int V = P1;
+// expected-error at -1 {{constexpr variable 'V' must be initialized by a constant expression}}
+
+ constexpr int V1 = 12;
+ constexpr const int *V2 = &V1;
+// expected-error at -1 {{constexpr variable 'V2' must be initialized by a constant expression}}
+// expected-error at -2 {{constexpr pointer initializer is not null}}
+}
+
+// Check that initializer for constexpr variable should match the type of the
+// variable and is exactly representable int the variable's type.
+
+struct S6 {
+ unsigned char a;
+};
+
+struct S7 {
+ union {
+ float a;
+ };
+ unsigned int b;
+};
+
+void f5() {
+ constexpr char V50 = 300;
+ // expected-error at -1 {{constexpr initializer evaluates to 300 which is not exactly representable in type 'char'}}
+ constexpr float V51 = 1.0 / 3.0;
+ // expected-error at -1 {{constexpr initializer evaluates to 3.333333e-01 which is not exactly representable in type 'float'}}
+ constexpr float V52 = 0.7;
+ // expected-error at -1 {{constexpr initializer evaluates to 7.000000e-01 which is not exactly representable in type 'float'}}
+ constexpr float V53 = 1.0f / 3.0f;
+ constexpr float V54 = 432000000000;
+ // expected-error at -1 {{constexpr initializer evaluates to 432000000000 which is not exactly representable in type 'float'}}
+ constexpr unsigned char V55[] = {
+ "\xAF",
+ // expected-error at -1 {{constexpr initializer evaluates to -81 which is not exactly representable in type 'const unsigned char'}}
+ };
+
+ constexpr unsigned char V56[] = {
+ u8"\xAF",
+ };
+ constexpr struct S6 V57 = {299};
+ // expected-error at -1 {{constexpr initializer evaluates to 299 which is not exactly representable in type 'unsigned char'}}
+ constexpr struct S6 V58 = {-299};
+ // expected-error at -1 {{constexpr initializer evaluates to -299 which is not exactly representable in type 'unsigned char'}}
+ constexpr double V59 = 0.5;
+ constexpr double V60 = 1.0;
+ constexpr float V61 = V59 / V60;
+ constexpr double V62 = 1.7;
+ constexpr float V63 = V59 / V62;
+ // expected-error at -1 {{constexpr initializer evaluates to 2.941176e-01 which is not exactly representable in type 'float'}}
+
+ constexpr unsigned char V64 = '\xAF';
+ // expected-error at -1 {{constexpr initializer evaluates to -81 which is not exactly representable in type 'unsigned char'}}
+ constexpr unsigned char V65 = u8'\xAF';
+
+ constexpr char V66[3] = {300};
+ // expected-error at -1 {{constexpr initializer evaluates to 300 which is not exactly representable in type 'char'}}
+ constexpr struct S6 V67[3] = {300};
+ // expected-error at -1 {{constexpr initializer evaluates to 300 which is not exactly representable in type 'unsigned char'}}
+
+ constexpr struct S7 V68 = {0.3, -1 };
+ // expected-error at -1 {{constexpr initializer evaluates to 3.000000e-01 which is not exactly representable in type 'float'}}
+ constexpr struct S7 V69 = {0.5, -1 };
+ // expected-error at -1 {{constexpr initializer evaluates to -1 which is not exactly representable in type 'unsigned int'}}
+ constexpr struct S7 V70[3] = {{123456789}};
+ // expected-error at -1 {{constexpr initializer evaluates to 123456789 which is not exactly representable in type 'float'}}
+
+ constexpr int V71 = 0.3;
+ // expected-error at -1 {{constexpr initializer for type 'int' is of type 'double'}}
+ constexpr int V72 = V59;
+ // expected-error at -1 {{constexpr initializer for type 'int' is of type 'const double'}}
+ constexpr struct S6 V73 = {V59};
+ // expected-error at -1 {{constexpr initializer for type 'unsigned char' is of type 'const double'}}
+
+ constexpr float V74 = 1;
+ constexpr float V75 = V59;
+ constexpr unsigned int V76[3] = {0.5};
+ // expected-error at -1 {{constexpr initializer for type 'unsigned int' is of type 'double'}}
+
+ constexpr _Complex float V77 = 0;
+ constexpr float V78 = V77;
+ // expected-error at -1 {{constexpr initializer for type 'float' is of type 'const _Complex float'}}
+ constexpr int V79 = V77;
+ // expected-error at -1 {{constexpr initializer for type 'int' is of type 'const _Complex float'}}
+
+}
+
+constexpr char string[] = "test""ing this out\xFF";
+constexpr unsigned char ustring[] = "test""ing this out\xFF";
+// expected-error at -1 {{constexpr initializer evaluates to -1 which is not exactly representable in type 'const unsigned char'}}
+constexpr char u8string[] = u8"test"u8"ing this out\xFF";
+// expected-error at -1 {{constexpr initializer evaluates to 255 which is not exactly representable in type 'const char'}}
+constexpr unsigned char u8ustring[] = u8"test"u8"ing this out\xFF";
+constexpr unsigned short uustring[] = u"test"u"ing this out\xFF";
+constexpr unsigned int Ustring[] = U"test"U"ing this out\xFF";
+
+constexpr int i = (12);
+constexpr int j = (i);
+constexpr unsigned jneg = (-i);
+// expected-error at -1 {{constexpr initializer evaluates to -12 which is not exactly representable in type 'unsigned int'}}
+
+// Check that initializer for pointer constexpr variable should be null.
+constexpr int V80 = 3;
+constexpr const int *V81 = &V80;
+// expected-error at -1 {{constexpr pointer initializer is not null}}
+constexpr int *V82 = 0;
+constexpr int *V83 = V82;
+constexpr int *V84 = 42;
+// expected-error at -1 {{constexpr variable 'V84' must be initialized by a constant expression}}
+// expected-note at -2 {{this conversion is not allowed in a constant expression}}
+constexpr int *V85 = nullptr;
+
+// Check that constexpr variables should not be VLAs.
+void f6(const int P1) {
----------------
Fznamznon wrote:
Yep, checked at the end of the test.
https://github.com/llvm/llvm-project/pull/73099
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