clang/test/Sema/compare.c

   1 // RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -pedantic -verify -Wsign-compare -Wtautological-constant-in-range-compare %s -Wno-unreachable-code
   2 // RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -pedantic -verify -Wsign-compare -Wtype-limits %s -Wno-unreachable-code
   3
   4 int test(char *C) { // nothing here should warn.
   5   return C != ((void*)0);
   6   return C != (void*)0;
   7   return C != 0;
   8   return C != 1;  // expected-warning {{comparison between pointer and integer ('char *' and 'int')}}
   9 }
  10
  11 int ints(long a, unsigned long b) {
  12   enum EnumA {A};
  13   enum EnumB {B};
  14   enum EnumC {C = 0x10000};
  15   return
  16          // (a,b)
  17          (a == (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
  18          (a == (unsigned int) b) +
  19          (a == (unsigned short) b) +
  20          (a == (unsigned char) b) +
  21          ((long) a == b) +  // expected-warning {{comparison of integers of different signs}}
  22          ((int) a == b) +  // expected-warning {{comparison of integers of different signs}}
  23          ((short) a == b) +  // expected-warning {{comparison of integers of different signs}}
  24          ((signed char) a == b) +  // expected-warning {{comparison of integers of different signs}}
  25          ((long) a == (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
  26          ((int) a == (unsigned int) b) +  // expected-warning {{comparison of integers of different signs}}
  27          ((short) a == (unsigned short) b) +
  28          ((signed char) a == (unsigned char) b) +
  29          (a < (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
  30          (a < (unsigned int) b) +
  31          (a < (unsigned short) b) +
  32          (a < (unsigned char) b) +
  33          ((long) a < b) +  // expected-warning {{comparison of integers of different signs}}
  34          ((int) a < b) +  // expected-warning {{comparison of integers of different signs}}
  35          ((short) a < b) +  // expected-warning {{comparison of integers of different signs}}
  36          ((signed char) a < b) +  // expected-warning {{comparison of integers of different signs}}
  37          ((long) a < (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
  38          ((int) a < (unsigned int) b) +  // expected-warning {{comparison of integers of different signs}}
  39          ((short) a < (unsigned short) b) +
  40          ((signed char) a < (unsigned char) b) +
  41
  42          // (A,b)
  43          (A == (unsigned long) b) +
  44          (A == (unsigned int) b) +
  45          (A == (unsigned short) b) +
  46          (A == (unsigned char) b) +
  47          ((long) A == b) +
  48          ((int) A == b) +
  49          ((short) A == b) +
  50          ((signed char) A == b) +
  51          ((long) A == (unsigned long) b) +
  52          ((int) A == (unsigned int) b) +
  53          ((short) A == (unsigned short) b) +
  54          ((signed char) A == (unsigned char) b) +
  55          (A < (unsigned long) b) +
  56          (A < (unsigned int) b) +
  57          (A < (unsigned short) b) +
  58          (A < (unsigned char) b) +
  59          ((long) A < b) +
  60          ((int) A < b) +
  61          ((short) A < b) +
  62          ((signed char) A < b) +
  63          ((long) A < (unsigned long) b) +
  64          ((int) A < (unsigned int) b) +
  65          ((short) A < (unsigned short) b) +
  66          ((signed char) A < (unsigned char) b) +
  67
  68          // (a,B)
  69          (a == (unsigned long) B) +
  70          (a == (unsigned int) B) +
  71          (a == (unsigned short) B) +
  72          (a == (unsigned char) B) +
  73          ((long) a == B) +
  74          ((int) a == B) +
  75          ((short) a == B) +
  76          ((signed char) a == B) +
  77          ((long) a == (unsigned long) B) +
  78          ((int) a == (unsigned int) B) +
  79          ((short) a == (unsigned short) B) +
  80          ((signed char) a == (unsigned char) B) +
  81          (a < (unsigned long) B) +  // expected-warning {{comparison of unsigned expression < 0 is always false}}
  82          (a < (unsigned int) B) +
  83          (a < (unsigned short) B) +
  84          (a < (unsigned char) B) +
  85          ((long) a < B) +
  86          ((int) a < B) +
  87          ((short) a < B) +
  88          ((signed char) a < B) +
  89          ((long) a < (unsigned long) B) +  // expected-warning {{comparison of unsigned expression < 0 is always false}}
  90          ((int) a < (unsigned int) B) +  // expected-warning {{comparison of unsigned expression < 0 is always false}}
  91          ((short) a < (unsigned short) B) +
  92          ((signed char) a < (unsigned char) B) +
  93
  94          // (C,b)
  95          (C == (unsigned long) b) +
  96          (C == (unsigned int) b) +
  97          (C == (unsigned short) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned short' is always false}}
  98          (C == (unsigned char) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned char' is always false}}
  99          ((long) C == b) +
 100          ((int) C == b) +
 101          ((short) C == b) +
 102          ((signed char) C == b) +
 103          ((long) C == (unsigned long) b) +
 104          ((int) C == (unsigned int) b) +
 105          ((short) C == (unsigned short) b) +
 106          ((signed char) C == (unsigned char) b) +
 107          (C < (unsigned long) b) +
 108          (C < (unsigned int) b) +
 109          (C < (unsigned short) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned short' is always false}}
 110          (C < (unsigned char) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned char' is always false}}
 111          ((long) C < b) +
 112          ((int) C < b) +
 113          ((short) C < b) +
 114          ((signed char) C < b) +
 115          ((long) C < (unsigned long) b) +
 116          ((int) C < (unsigned int) b) +
 117          ((short) C < (unsigned short) b) +
 118          ((signed char) C < (unsigned char) b) +
 119
 120          // (a,C)
 121          (a == (unsigned long) C) +
 122          (a == (unsigned int) C) +
 123          (a == (unsigned short) C) +
 124          (a == (unsigned char) C) +
 125          ((long) a == C) +
 126          ((int) a == C) +
 127          ((short) a == C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'short' is always false}}
 128          ((signed char) a == C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'signed char' is always false}}
 129          ((long) a == (unsigned long) C) +
 130          ((int) a == (unsigned int) C) +
 131          ((short) a == (unsigned short) C) +
 132          ((signed char) a == (unsigned char) C) +
 133          (a < (unsigned long) C) +  // expected-warning {{comparison of integers of different signs}}
 134          (a < (unsigned int) C) +
 135          (a < (unsigned short) C) +
 136          (a < (unsigned char) C) +
 137          ((long) a < C) +
 138          ((int) a < C) +
 139          ((short) a < C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'short' is always true}}
 140          ((signed char) a < C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'signed char' is always true}}
 141          ((long) a < (unsigned long) C) +  // expected-warning {{comparison of integers of different signs}}
 142          ((int) a < (unsigned int) C) +  // expected-warning {{comparison of integers of different signs}}
 143          ((short) a < (unsigned short) C) +
 144          ((signed char) a < (unsigned char) C) +
 145
 146          // (0x80000,b)
 147          (0x80000 == (unsigned long) b) +
 148          (0x80000 == (unsigned int) b) +
 149          (0x80000 == (unsigned short) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned short' is always false}}
 150          (0x80000 == (unsigned char) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned char' is always false}}
 151          ((long) 0x80000 == b) +
 152          ((int) 0x80000 == b) +
 153          ((short) 0x80000 == b) +
 154          ((signed char) 0x80000 == b) +
 155          ((long) 0x80000 == (unsigned long) b) +
 156          ((int) 0x80000 == (unsigned int) b) +
 157          ((short) 0x80000 == (unsigned short) b) +
 158          ((signed char) 0x80000 == (unsigned char) b) +
 159          (0x80000 < (unsigned long) b) +
 160          (0x80000 < (unsigned int) b) +
 161          (0x80000 < (unsigned short) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned short' is always false}}
 162          (0x80000 < (unsigned char) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned char' is always false}}
 163          ((long) 0x80000 < b) +
 164          ((int) 0x80000 < b) +
 165          ((short) 0x80000 < b) +
 166          ((signed char) 0x80000 < b) +
 167          ((long) 0x80000 < (unsigned long) b) +
 168          ((int) 0x80000 < (unsigned int) b) +
 169          ((short) 0x80000 < (unsigned short) b) +
 170          ((signed char) 0x80000 < (unsigned char) b) +
 171
 172          // (a,0x80000)
 173          (a == (unsigned long) 0x80000) +
 174          (a == (unsigned int) 0x80000) +
 175          (a == (unsigned short) 0x80000) +
 176          (a == (unsigned char) 0x80000) +
 177          ((long) a == 0x80000) +
 178          ((int) a == 0x80000) +
 179          ((short) a == 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'short' is always false}}
 180          ((signed char) a == 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'signed char' is always false}}
 181          ((long) a == (unsigned long) 0x80000) +
 182          ((int) a == (unsigned int) 0x80000) +
 183          ((short) a == (unsigned short) 0x80000) +
 184          ((signed char) a == (unsigned char) 0x80000) +
 185          (a < (unsigned long) 0x80000) +  // expected-warning {{comparison of integers of different signs}}
 186          (a < (unsigned int) 0x80000) +
 187          (a < (unsigned short) 0x80000) +
 188          (a < (unsigned char) 0x80000) +
 189          ((long) a < 0x80000) +
 190          ((int) a < 0x80000) +
 191          ((short) a < 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'short' is always true}}
 192          ((signed char) a < 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'signed char' is always true}}
 193          ((long) a < (unsigned long) 0x80000) +  // expected-warning {{comparison of integers of different signs}}
 194          ((int) a < (unsigned int) 0x80000) +  // expected-warning {{comparison of integers of different signs}}
 195          ((short) a < (unsigned short) 0x80000) +
 196          ((signed char) a < (unsigned char) 0x80000) +
 197
 198          // We should be able to avoid warning about this.
 199          (b != (a < 4 ? 1 : 2)) +
 200
 201          10
 202     ;
 203 }
 204
 205 int equal(char *a, const char *b) {
 206     return a == b;
 207 }
 208
 209 int arrays(char (*a)[5], char(*b)[10], char(*c)[5]) {
 210   int d = (a == c);
 211   return a == b; // expected-warning {{comparison of distinct pointer types}}
 212 }
 213
 214 int pointers(int *a) {
 215   return a > 0; // expected-warning {{ordered comparison between pointer and zero ('int *' and 'int') is an extension}}
 216   return a > 42; // expected-warning {{ordered comparison between pointer and integer ('int *' and 'int')}}
 217   return a > (void *)0; // expected-warning {{comparison of distinct pointer types}}
 218 }
 219
 220 int function_pointers(int (*a)(int), int (*b)(int), void (*c)(int)) {
 221   return a > b; // expected-warning {{ordered comparison of function pointers}}
 222   return function_pointers > function_pointers; // expected-warning {{self-comparison always evaluates to false}} expected-warning{{ordered comparison of function pointers}}
 223   return a > c;                                 // expected-warning {{comparison of distinct pointer types}} expected-warning {{ordered comparison of function pointers}}
 224   return a == (void *) 0;
 225   return a == (void *) 1; // expected-warning {{equality comparison between function pointer and void pointer}}
 226 }
 227
 228 int void_pointers(void* foo) {
 229   return foo == (void*) 0;
 230   return foo == (void*) 1;
 231 }
 232
 233
 234 int test1(int i) {
 235   enum en { zero };
 236   return i > zero;
 237 }
 238
 239 // PR5937
 240 int test2(int i32) {
 241   struct foo {
 242     unsigned int u8 : 8;
 243     unsigned long long u31 : 31;
 244     unsigned long long u32 : 32;
 245     unsigned long long u63 : 63;
 246     unsigned long long u64 : 64;
 247   } *x;
 248
 249   if (x->u8 == i32) { // comparison in int32, exact
 250     return 0;
 251   } else if (x->u31 == i32) { // comparison in int32, exact
 252     return 1;
 253   } else if (x->u32 == i32) { // expected-warning {{comparison of integers of different signs}}
 254     return 2;
 255   } else if (x->u63 == i32) { // comparison in uint64, exact because ==
 256     return 3;
 257   } else if (x->u64 == i32) { // expected-warning {{comparison of integers of different signs}}
 258     return 4;
 259   } else {
 260     return 5;
 261   }
 262 }
 263
 264 // PR5887
 265 void test3(void) {
 266   unsigned short x, y;
 267   unsigned int z;
 268   if ((x > y ? x : y) > z)
 269     (void) 0;
 270 }
 271
 272 // PR5961
 273 extern char *ptr4;
 274 void test4(void) {
 275   long value;
 276   if (value < (unsigned long) &ptr4) // expected-warning {{comparison of integers of different signs}}
 277     return;
 278 }
 279
 280 // PR4807
 281 int test5(unsigned int x) {
 282   return (x < 0) // expected-warning {{comparison of unsigned expression < 0 is always false}}
 283     && (0 > x)   // expected-warning {{comparison of 0 > unsigned expression is always false}}
 284     && (x >= 0)  // expected-warning {{comparison of unsigned expression >= 0 is always true}}
 285     && (0 <= x); // expected-warning {{comparison of 0 <= unsigned expression is always true}}
 286 }
 287
 288 struct bitfield {
 289   int a : 3;
 290   unsigned b : 3;
 291   long c : 40;
 292   unsigned long d : 40;
 293 };
 294
 295 void test5a(struct bitfield a) {
 296   if (a.a < 0) {}
 297   if (a.b < 0) {} // expected-warning {{comparison of unsigned expression < 0 is always false}}
 298   if (a.c < 0) {}
 299   if (a.d < 0) {} // expected-warning {{comparison of unsigned expression < 0 is always false}}
 300 }
 301
 302 int test6(unsigned i, unsigned power) {
 303   unsigned x = (i < (1 << power) ? i : 0);
 304   return x != 3 ? 1 << power : i;
 305 }
 306
 307 // enum >= (enum)0 comparison should not generate any warnings
 308 enum rdar8414119_Vals { X, Y, Z };
 309 #define ZERO 0
 310 #define CHECK(x) (x >= X)
 311 void rdar8414119_foo(enum rdar8414119_Vals v) {
 312   if (CHECK(v)) // no-warning
 313    return;
 314   if (v >= X) // no-warning
 315    return;
 316 }
 317 int rdar8414119_bar(unsigned x) {
 318   return x >= ZERO; // no-warning
 319 }
 320 #undef ZERO
 321 #undef CHECK
 322
 323 int rdar8511238(void) {
 324   enum A { A_foo, A_bar };
 325   enum A a;
 326
 327   if (a == 0)
 328       return 0;
 329   if (a != 0)
 330       return 0;
 331   if (a < 0) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
 332       return 0;
 333   if (a <= 0)
 334       return 0;
 335   if (a > 0)
 336       return 0;
 337   if (a >= 0) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
 338       return 0;
 339
 340   if (0 == a)
 341       return 0;
 342   if (0 != a)
 343       return 0;
 344   if (0 < a)
 345       return 0;
 346   if (0 <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
 347       return 0;
 348   if (0 > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
 349       return 0;
 350   if (0 >= a)
 351       return 0;
 352
 353   if (a == 0U)
 354       return 0;
 355   if (a != 0U)
 356       return 0;
 357   if (a < 0U) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
 358       return 0;
 359   if (a <= 0U)
 360       return 0;
 361   if (a > 0U)
 362       return 0;
 363   if (a >= 0U) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
 364       return 0;
 365
 366   if (0U == a)
 367       return 0;
 368   if (0U != a)
 369       return 0;
 370   if (0U < a)
 371       return 0;
 372   if (0U <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
 373       return 0;
 374   if (0U > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
 375       return 0;
 376   if (0U >= a)
 377       return 0;
 378
 379   return 20;
 380 }
 381
 382 // PR10336
 383 int test9(int sv, unsigned uv, long slv) {
 384   return sv == (uv ^= slv); // expected-warning {{comparison of integers of different signs: 'int' and 'unsigned int'}}
 385 }
 386
 387 void test10(void) {
 388   int si;
 389   unsigned int ui;
 390   long sl;
 391
 392   _Bool b;
 393   b = (si == (ui = sl)); // expected-warning {{comparison of integers of different signs: 'int' and 'unsigned int'}}
 394   b = (si == (ui = sl&15));
 395 }
 396
 397 // PR11572
 398 struct test11S { unsigned x : 30; };
 399 int test11(unsigned y, struct test11S *p) {
 400   return y > (p->x >> 24); // no-warning
 401 }
 402
 403 typedef char one_char[1];
 404 typedef char two_chars[2];
 405
 406 void test12(unsigned a) {
 407   if (0 && -1 > a) { }
 408 }
 409
 410 // PR36008
 411
 412 enum PR36008EnumTest {
 413   kPR36008Value = 0,
 414 };
 415
 416 void pr36008(enum PR36008EnumTest lhs) {
 417   __typeof__(lhs) x = lhs;
 418   __typeof__(kPR36008Value) y = (kPR36008Value);
 419   if (x == y) x = y; // no warning
 420   if (y == x) y = x; // no warning
 421 }