clang/test/AST/ByteCode/constexpr.c

   1 // RUN: %clang_cc1 -std=c23 -verify=ref,both -triple x86_64 -pedantic -Wno-conversion -Wno-constant-conversion -Wno-div-by-zero %s
   2 // RUN: %clang_cc1 -std=c23 -verify=expected,both -triple x86_64 -pedantic -Wno-conversion -Wno-constant-conversion -Wno-div-by-zero -fexperimental-new-constant-interpreter %s
   3
   4 // Check that constexpr only applies to variables.
   5 constexpr void f0() {} // both-error {{'constexpr' can only be used in variable declarations}}
   6 constexpr const int f1() { return 0; } // both-error {{'constexpr' can only be used in variable declarations}}
   7
   8 constexpr struct S1 { int f; }; //both-error {{struct cannot be marked constexpr}}
   9 constexpr struct S2 ; // both-error {{struct cannot be marked constexpr}}
  10 constexpr union U1; // both-error {{union cannot be marked constexpr}}
  11 constexpr union U2 {int a; float b;}; // both-error {{union cannot be marked constexpr}}
  12 constexpr enum E1 {A = 1, B = 2} ; // both-error {{enum cannot be marked constexpr}}
  13 struct S3 {
  14   static constexpr int f = 0; // both-error {{type name does not allow storage class}}
  15   // both-error@-1 {{type name does not allow constexpr}}
  16   // both-error@-2 {{expected ';' at end}}
  17   constexpr int f1 = 0;
  18   // both-error@-1 {{type name does not allow constexpr}}
  19   // both-error@-2 {{expected ';' at end}}
  20 };
  21
  22 constexpr; // both-error {{'constexpr' can only be used in variable declarations}}
  23 constexpr int V1 = 3;
  24 constexpr float V2 = 7.0;
  25 int V3 = (constexpr)3; // both-error {{expected expression}}
  26
  27 void f2() {
  28   constexpr int a = 0;
  29   constexpr float b = 1.7f;
  30 }
  31
  32 // Check how constexpr works with other storage-class specifiers.
  33 constexpr auto V4 = 1;
  34 constexpr static auto V5 = 1;
  35 constexpr static const auto V6 = 1;
  36 constexpr static const int V7 = 1;
  37 constexpr static int V8 = 1;
  38 constexpr auto Ulong = 1L;
  39 constexpr auto CompoundLiteral = (int){13};
  40 constexpr auto DoubleCast = (double)(1 / 3);
  41 constexpr auto String = "this is a string"; // both-error {{constexpr pointer initializer is not null}}
  42 constexpr signed auto Long = 1L; // both-error {{'auto' cannot be signed or unsigned}}
  43 _Static_assert(_Generic(Ulong, long : 1));
  44 _Static_assert(_Generic(CompoundLiteral, int : 1));
  45 _Static_assert(_Generic(DoubleCast, double : 1));
  46 _Static_assert(_Generic(String, char* : 1));
  47
  48 typedef constexpr int Foo; // both-error {{typedef cannot be constexpr}}
  49 constexpr typedef int Bar; // both-error {{typedef cannot be constexpr}}
  50
  51 void f3(constexpr register int P1) { // both-error {{function parameter cannot be constexpr}}
  52   constexpr register int V9 = 0;
  53   constexpr register auto V10 = 0.0;
  54 }
  55
  56 constexpr thread_local int V11 = 38; // both-error {{cannot combine with previous '_Thread_local' declaration specifier}}
  57 constexpr static thread_local double V12 = 38; // both-error {{cannot combine with previous '_Thread_local' declaration specifier}}
  58 constexpr extern thread_local char V13; // both-error {{cannot combine with previous '_Thread_local' declaration specifier}}
  59 // both-error@-1 {{cannot combine with previous 'extern' declaration specifier}}
  60 // both-error@-2 {{constexpr variable declaration must be a definition}}
  61 constexpr thread_local short V14 = 38; // both-error {{cannot combine with previous '_Thread_local' declaration specifier}}
  62
  63 // Check how constexpr works with qualifiers.
  64 constexpr _Atomic int V15 = 0; // both-error {{constexpr variable cannot have type 'const _Atomic(int)'}}
  65 constexpr _Atomic(int) V16 = 0; // both-error {{constexpr variable cannot have type 'const _Atomic(int)'}}
  66
  67 constexpr volatile int V17 = 0; // both-error {{constexpr variable cannot have type 'const volatile int'}}
  68
  69 constexpr int * restrict V18 = 0; // both-error {{constexpr variable cannot have type 'int *const restrict'}}
  70
  71 constexpr extern char Oops = 1; // both-error {{cannot combine with previous 'extern' declaration specifier}} \
  72                                 // both-warning {{'extern' variable has an initializer}}
  73
  74 constexpr int * restrict * Oops1 = 0;
  75
  76 typedef _Atomic(int) TheA;
  77 typedef volatile short TheV;
  78 typedef float * restrict TheR;
  79
  80 constexpr TheA V19[3] = {};
  81 // both-error@-1 {{constexpr variable cannot have type 'const TheA[3]' (aka 'const _Atomic(int)[3]')}}
  82 constexpr TheV V20[3] = {};
  83 // both-error@-1 {{constexpr variable cannot have type 'const TheV[3]' (aka 'const volatile short[3]')}}
  84 constexpr TheR V21[3] = {};
  85 // both-error@-1 {{constexpr variable cannot have type 'const TheR[3]' (aka 'float *restrict const[3]')}}
  86
  87 struct HasA {
  88   TheA f;
  89   int b;
  90 };
  91
  92 struct HasV {
  93   float b;
  94   TheV f;
  95 };
  96
  97 struct HasR {
  98   short b;
  99   int a;
 100   TheR f;
 101 };
 102
 103 constexpr struct HasA V22[2] = {};
 104 // both-error@-1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
 105 constexpr struct HasV V23[2] = {};
 106 // both-error@-1 {{constexpr variable cannot have type 'TheV' (aka 'volatile short')}}
 107 constexpr struct HasR V24[2] = {};
 108 // both-error@-1 {{constexpr variable cannot have type 'TheR' (aka 'float *restrict')}}
 109
 110 union U3 {
 111   float a;
 112   union {
 113     struct HasA f;
 114     struct HasR f1;
 115   };
 116 };
 117
 118 constexpr union U3 V25 = {};
 119 // both-error@-1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
 120 constexpr union U3 V26[8] = {};
 121 // both-error@-1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
 122
 123 struct S4 {
 124   union U3 f[3];
 125 };
 126
 127 constexpr struct S4 V27 = {};
 128 // both-error@-1 {{constexpr variable cannot have type 'TheA' (aka '_Atomic(int)')}}
 129 constexpr const int V28 = 28;
 130
 131 struct S {
 132   union {
 133     volatile int i;
 134   };
 135   int j;
 136 };
 137
 138 constexpr struct S s = {}; // both-error {{constexpr variable cannot have type 'volatile int'}}
 139
 140 // Check that constexpr variable must have a valid initializer which is a
 141 // constant expression.
 142 constexpr int V29;
 143 // both-error@-1 {{constexpr variable 'V29' must be initialized by a constant expression}}
 144
 145 struct S5 {
 146   int f;
 147 };
 148
 149 constexpr struct S5 V30;
 150 // both-error@-1 {{constexpr variable 'V30' must be initialized by a constant expression}}
 151 constexpr struct S5 V31 = {};
 152
 153 int randomFoo() { return 7; }
 154
 155 constexpr float V32 = randomFoo();
 156 // both-error@-1 {{constexpr variable 'V32' must be initialized by a constant expression}}
 157
 158 const int V33 = 4;
 159 const int V34 = 0;
 160 const int V35 = 2;
 161
 162 constexpr int V36 = V33 / V34;
 163 // both-error@-1 {{constexpr variable 'V36' must be initialized by a constant expression}}
 164 constexpr int V37 = V33 / V35;
 165 // both-error@-1 {{constexpr variable 'V37' must be initialized by a constant expression}}
 166 constexpr int V38 = 3;
 167 constexpr int V39 = V38 / V38;
 168 constexpr int V40 = V38 / 2;
 169 constexpr int V41 = V38 / 0;
 170 // both-error@-1 {{constexpr variable 'V41' must be initialized by a constant expression}}
 171 // both-note@-2 {{division by zero}}
 172 constexpr int V42 = V38 & 0;
 173
 174 constexpr struct S5 V43 = { randomFoo() };
 175 // both-error@-1 {{constexpr variable 'V43' must be initialized by a constant expression}}
 176 constexpr struct S5 V44 = { 0 };
 177 constexpr struct S5 V45 = { V38 / 0 };
 178 // both-error@-1 {{constexpr variable 'V45' must be initialized by a constant expression}}
 179 // both-note@-2 {{division by zero}}
 180
 181 constexpr float V46[3] = {randomFoo() };
 182 // both-error@-1 {{constexpr variable 'V46' must be initialized by a constant expression}}
 183 constexpr struct S5 V47[3] = {randomFoo() };
 184 // both-error@-1 {{constexpr variable 'V47' must be initialized by a constant expression}}
 185
 186 const static int V48 = V38;
 187 constexpr static int V49 = V48;
 188 // both-error@-1 {{constexpr variable 'V49' must be initialized by a constant expression}}
 189
 190 void f4(const int P1) {
 191   constexpr int V = P1;
 192 // both-error@-1 {{constexpr variable 'V' must be initialized by a constant expression}}
 193
 194   constexpr int V1 = 12;
 195   constexpr const int *V2 = &V1;
 196 // both-error@-1 {{constexpr variable 'V2' must be initialized by a constant expression}}
 197 }
 198
 199 // Check that initializer for constexpr variable should match the type of the
 200 // variable and is exactly representable int the variable's type.
 201
 202 struct S6 {
 203   unsigned char a;
 204 };
 205
 206 struct S7 {
 207   union {
 208     float a;
 209   };
 210   unsigned int b;
 211 };
 212
 213 struct S8 {
 214   unsigned char a[3];
 215   unsigned int b[3];
 216 };
 217
 218 constexpr struct S8 DesigInit = {.b = {299, 7, 8}, .a = {-1, 7, 8}};
 219 // both-error@-1 {{constexpr initializer evaluates to -1 which is not exactly representable in type 'unsigned char'}}
 220
 221 void f5() {
 222   constexpr char V50 = 300;
 223   // both-error@-1 {{constexpr initializer evaluates to 300 which is not exactly representable in type 'const char'}}
 224   constexpr float V51 = 1.0 / 3.0;
 225   // both-error@-1 {{constexpr initializer evaluates to 3.333333e-01 which is not exactly representable in type 'const float'}}
 226   constexpr float V52 = 0.7;
 227   // both-error@-1 {{constexpr initializer evaluates to 7.000000e-01 which is not exactly representable in type 'const float'}}
 228   constexpr float V53 = 1.0f / 3.0f;
 229   constexpr float V54 = 432000000000;
 230   // both-error@-1 {{constexpr initializer evaluates to 432000000000 which is not exactly representable in type 'const float'}}
 231   constexpr unsigned char V55[] = {
 232       "\xAF",
 233   // both-error@-1 {{constexpr initializer evaluates to -81 which is not exactly representable in type 'const unsigned char'}}
 234   };
 235
 236   constexpr unsigned char V56[] = {
 237       u8"\xAF",
 238   };
 239   constexpr struct S6 V57 = {299};
 240   // both-error@-1 {{constexpr initializer evaluates to 299 which is not exactly representable in type 'unsigned char'}}
 241   constexpr struct S6 V58 = {-299};
 242   // both-error@-1 {{constexpr initializer evaluates to -299 which is not exactly representable in type 'unsigned char'}}
 243   constexpr double V59 = 0.5;
 244   constexpr double V60 = 1.0;
 245   constexpr float V61 = V59 / V60;
 246   constexpr double V62 = 1.7;
 247   constexpr float V63 = V59 / V62;
 248   // both-error@-1 {{constexpr initializer evaluates to 2.941176e-01 which is not exactly representable in type 'const float'}}
 249
 250   constexpr unsigned char V64 = '\xAF';
 251   // both-error@-1 {{constexpr initializer evaluates to -81 which is not exactly representable in type 'const unsigned char'}}
 252   constexpr unsigned char V65 = u8'\xAF';
 253
 254   constexpr char V66[3] = {300};
 255   // both-error@-1 {{constexpr initializer evaluates to 300 which is not exactly representable in type 'const char'}}
 256   constexpr struct S6 V67[3] = {300};
 257   // both-error@-1 {{constexpr initializer evaluates to 300 which is not exactly representable in type 'unsigned char'}}
 258
 259   constexpr struct S7 V68 = {0.3, -1 };
 260   // both-error@-1 {{constexpr initializer evaluates to 3.000000e-01 which is not exactly representable in type 'float'}}
 261   // both-error@-2 {{constexpr initializer evaluates to -1 which is not exactly representable in type 'unsigned int'}}
 262   constexpr struct S7 V69 = {0.5, -1 };
 263   // both-error@-1 {{constexpr initializer evaluates to -1 which is not exactly representable in type 'unsigned int'}}
 264   constexpr struct S7 V70[3] = {{123456789}};
 265   // both-error@-1 {{constexpr initializer evaluates to 123456789 which is not exactly representable in type 'float'}}
 266
 267   constexpr int V71 = 0.3;
 268   // both-error@-1 {{constexpr initializer for type 'const int' is of type 'double'}}
 269   constexpr int V72 = V59;
 270   // both-error@-1 {{constexpr initializer for type 'const int' is of type 'const double'}}
 271   constexpr struct S6 V73 = {V59};
 272   // both-error@-1 {{constexpr initializer for type 'unsigned char' is of type 'const double'}}
 273
 274   constexpr float V74 = 1;
 275   constexpr float V75 = V59;
 276   constexpr unsigned int V76[3] = {0.5};
 277   // both-error@-1 {{constexpr initializer for type 'const unsigned int' is of type 'double'}}
 278
 279   constexpr _Complex float V77 = 0;
 280   constexpr float V78 = V77;
 281   // both-error@-1 {{constexpr initializer for type 'const float' is of type 'const _Complex float'}}
 282   constexpr int V79 = V77;
 283   // both-error@-1 {{constexpr initializer for type 'const int' is of type 'const _Complex float'}}
 284
 285 }
 286
 287 constexpr char string[] = "test""ing this out\xFF";
 288 constexpr unsigned char ustring[] = "test""ing this out\xFF";
 289 // both-error@-1 {{constexpr initializer evaluates to -1 which is not exactly representable in type 'const unsigned char'}}
 290 constexpr char u8string[] = u8"test"u8"ing this out\xFF";
 291 // both-error@-1 {{constexpr initializer evaluates to 255 which is not exactly representable in type 'const char'}}
 292 constexpr unsigned char u8ustring[] = u8"test"u8"ing this out\xFF";
 293 constexpr unsigned short uustring[] = u"test"u"ing this out\xFF";
 294 constexpr unsigned int Ustring[] = U"test"U"ing this out\xFF";
 295 constexpr unsigned char Arr2[6][6] = {
 296   {"ek\xFF"}, {"ek\xFF"}
 297 // both-error@-1 2{{constexpr initializer evaluates to -1 which is not exactly representable in type 'const unsigned char'}}
 298 };
 299
 300 constexpr int i = (12);
 301 constexpr int j = (i);
 302 constexpr unsigned jneg = (-i);
 303 // both-error@-1 {{constexpr initializer evaluates to -12 which is not exactly representable in type 'const unsigned int'}}
 304
 305 // Check that initializer for pointer constexpr variable should be null.
 306 constexpr int V80 = 3;
 307 constexpr const int *V81 = &V80;
 308 // both-error@-1 {{constexpr pointer initializer is not null}}
 309 constexpr int *V82 = 0;
 310 constexpr int *V83 = V82;
 311 constexpr int *V84 = 42;
 312 // ref-error@-1 {{constexpr variable 'V84' must be initialized by a constant expression}}
 313 // ref-note@-2 {{this conversion is not allowed in a constant expression}}
 314 // both-error@-3 {{constexpr pointer initializer is not null}}
 315 constexpr int *V85 = nullptr;
 316
 317 // Check that constexpr variables should not be VLAs.
 318 void f6(const int P1) {
 319   constexpr int V86[P1] = {};
 320 // both-error@-1 {{constexpr variable cannot have type 'const int[P1]'}}
 321   const int V87 = 3;
 322   constexpr int V88[V87] = {};
 323 // both-warning@-1 {{variable length array folded to constant array as an extension}}
 324   int V89 = 7;
 325   constexpr int V90[V89] = {};
 326 // both-error@-1 {{constexpr variable cannot have type 'const int[V89]'}}
 327 }
 328
 329 void f7(int n, int array[n]) {
 330   constexpr typeof(array) foo = 0; // Accepted because array is a pointer type, not a VLA type
 331   int (*(*fp)(int n))[n];
 332   constexpr typeof(fp) bar = 0; // both-error {{constexpr variable cannot have type 'const typeof (fp)' (aka 'int (*(*const)(int))[n]')}}
 333 }
 334
 335 // Check how constexpr works with NaNs and infinities.
 336 #define FLT_NAN __builtin_nanf("1")
 337 #define DBL_NAN __builtin_nan("1")
 338 #define LD_NAN __builtin_nanf("1")
 339 #define FLT_SNAN __builtin_nansf("1")
 340 #define DBL_SNAN __builtin_nans("1")
 341 #define LD_SNAN __builtin_nansl("1")
 342 #define INF __builtin_inf()
 343 void infsNaNs() {
 344   // Inf and quiet NaN is always fine, signaling NaN must have the same type.
 345   constexpr float fl0 = INF;
 346   constexpr float fl1 = (long double)INF;
 347   constexpr float fl2 = (long double)FLT_NAN;
 348   constexpr float fl3 = FLT_NAN;
 349   constexpr float fl5 = DBL_NAN;
 350   constexpr float fl6 = LD_NAN;
 351   constexpr float fl7 = DBL_SNAN; // both-error {{constexpr initializer evaluates to nan which is not exactly representable in type 'const float'}}
 352   constexpr float fl8 = LD_SNAN; // both-error {{constexpr initializer evaluates to nan which is not exactly representable in type 'const float'}}
 353
 354   constexpr double db0 = FLT_NAN;
 355   constexpr double db2 = DBL_NAN;
 356   constexpr double db3 = DBL_SNAN;
 357   constexpr double db4 = FLT_SNAN; // both-error {{constexpr initializer evaluates to nan which is not exactly representable in type 'const double'}}
 358   constexpr double db5 = LD_SNAN; // both-error {{constexpr initializer evaluates to nan which is not exactly representable in type 'const double'}}
 359   constexpr double db6 = INF;
 360 }
 361
 362 constexpr struct S9 s9 = {  }; // both-error {{variable has incomplete type 'const struct S9'}} \
 363                                // both-note {{forward declaration of 'struct S9'}}
 364
 365 struct S10 {
 366   signed long long i : 8;
 367 };
 368 constexpr struct S10 c = { 255 };
 369 // FIXME-expected-error@-1 {{constexpr initializer evaluates to 255 which is not exactly representable in 'long long' bit-field with width 8}}
 370 // See: GH#101299