llvm-project/clang/test/Sema/compare.c

// RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -pedantic -verify -Wsign-compare -Wtautological-constant-in-range-compare %s -Wno-unreachable-code

int test(char *C) { // nothing here should warn.
  return C != ((void*)0);
  return C != (void*)0;
  return C != 0;
  return C != 1;  // expected-warning {{comparison between pointer and integer ('char *' and 'int')}}
}

int ints(long a, unsigned long b) {
  enum EnumA {A};
  enum EnumB {B};
  enum EnumC {C = 0x10000};
  return
         // (a,b)
         (a == (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
         (a == (unsigned int) b) +
         (a == (unsigned short) b) +
         (a == (unsigned char) b) +
         ((long) a == b) +  // expected-warning {{comparison of integers of different signs}}
         ((int) a == b) +  // expected-warning {{comparison of integers of different signs}}
         ((short) a == b) +  // expected-warning {{comparison of integers of different signs}}
         ((signed char) a == b) +  // expected-warning {{comparison of integers of different signs}}
         ((long) a == (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
         ((int) a == (unsigned int) b) +  // expected-warning {{comparison of integers of different signs}}
         ((short) a == (unsigned short) b) +
         ((signed char) a == (unsigned char) b) +
         (a < (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
         (a < (unsigned int) b) +
         (a < (unsigned short) b) +
         (a < (unsigned char) b) +
         ((long) a < b) +  // expected-warning {{comparison of integers of different signs}}
         ((int) a < b) +  // expected-warning {{comparison of integers of different signs}}
         ((short) a < b) +  // expected-warning {{comparison of integers of different signs}}
         ((signed char) a < b) +  // expected-warning {{comparison of integers of different signs}}
         ((long) a < (unsigned long) b) +  // expected-warning {{comparison of integers of different signs}}
         ((int) a < (unsigned int) b) +  // expected-warning {{comparison of integers of different signs}}
         ((short) a < (unsigned short) b) +
         ((signed char) a < (unsigned char) b) +

         // (A,b)
         (A == (unsigned long) b) +
         (A == (unsigned int) b) +
         (A == (unsigned short) b) +
         (A == (unsigned char) b) +
         ((long) A == b) +
         ((int) A == b) +
         ((short) A == b) +
         ((signed char) A == b) +
         ((long) A == (unsigned long) b) +
         ((int) A == (unsigned int) b) +
         ((short) A == (unsigned short) b) +
         ((signed char) A == (unsigned char) b) +
         (A < (unsigned long) b) +
         (A < (unsigned int) b) +
         (A < (unsigned short) b) +
         (A < (unsigned char) b) +
         ((long) A < b) +
         ((int) A < b) +
         ((short) A < b) +
         ((signed char) A < b) +
         ((long) A < (unsigned long) b) +
         ((int) A < (unsigned int) b) +
         ((short) A < (unsigned short) b) +
         ((signed char) A < (unsigned char) b) +

         // (a,B)
         (a == (unsigned long) B) +
         (a == (unsigned int) B) +
         (a == (unsigned short) B) +
         (a == (unsigned char) B) +
         ((long) a == B) +
         ((int) a == B) +
         ((short) a == B) +
         ((signed char) a == B) +
         ((long) a == (unsigned long) B) +
         ((int) a == (unsigned int) B) +
         ((short) a == (unsigned short) B) +
         ((signed char) a == (unsigned char) B) +
         (a < (unsigned long) B) +  // expected-warning {{comparison of unsigned expression < 0 is always false}}
         (a < (unsigned int) B) +
         (a < (unsigned short) B) +
         (a < (unsigned char) B) +
         ((long) a < B) +
         ((int) a < B) +
         ((short) a < B) +
         ((signed char) a < B) +
         ((long) a < (unsigned long) B) +  // expected-warning {{comparison of unsigned expression < 0 is always false}}
         ((int) a < (unsigned int) B) +  // expected-warning {{comparison of unsigned expression < 0 is always false}}
         ((short) a < (unsigned short) B) +
         ((signed char) a < (unsigned char) B) +

         // (C,b)
         (C == (unsigned long) b) +
         (C == (unsigned int) b) +
         (C == (unsigned short) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned short' is always false}}
         (C == (unsigned char) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned char' is always false}}
         ((long) C == b) +
         ((int) C == b) +
         ((short) C == b) +
         ((signed char) C == b) +
         ((long) C == (unsigned long) b) +
         ((int) C == (unsigned int) b) +
         ((short) C == (unsigned short) b) +
         ((signed char) C == (unsigned char) b) +
         (C < (unsigned long) b) +
         (C < (unsigned int) b) +
         (C < (unsigned short) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned short' is always false}}
         (C < (unsigned char) b) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'unsigned char' is always false}}
         ((long) C < b) +
         ((int) C < b) +
         ((short) C < b) +
         ((signed char) C < b) +
         ((long) C < (unsigned long) b) +
         ((int) C < (unsigned int) b) +
         ((short) C < (unsigned short) b) +
         ((signed char) C < (unsigned char) b) +

         // (a,C)
         (a == (unsigned long) C) +
         (a == (unsigned int) C) +
         (a == (unsigned short) C) +
         (a == (unsigned char) C) +
         ((long) a == C) +
         ((int) a == C) +
         ((short) a == C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'short' is always false}}
         ((signed char) a == C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'signed char' is always false}}
         ((long) a == (unsigned long) C) +
         ((int) a == (unsigned int) C) +
         ((short) a == (unsigned short) C) +
         ((signed char) a == (unsigned char) C) +
         (a < (unsigned long) C) +  // expected-warning {{comparison of integers of different signs}}
         (a < (unsigned int) C) +
         (a < (unsigned short) C) +
         (a < (unsigned char) C) +
         ((long) a < C) +
         ((int) a < C) +
         ((short) a < C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'short' is always true}}
         ((signed char) a < C) + // expected-warning {{comparison of constant 'C' (65536) with expression of type 'signed char' is always true}}
         ((long) a < (unsigned long) C) +  // expected-warning {{comparison of integers of different signs}}
         ((int) a < (unsigned int) C) +  // expected-warning {{comparison of integers of different signs}}
         ((short) a < (unsigned short) C) +
         ((signed char) a < (unsigned char) C) +

         // (0x80000,b)
         (0x80000 == (unsigned long) b) +
         (0x80000 == (unsigned int) b) +
         (0x80000 == (unsigned short) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned short' is always false}}
         (0x80000 == (unsigned char) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned char' is always false}}
         ((long) 0x80000 == b) +
         ((int) 0x80000 == b) +
         ((short) 0x80000 == b) +
         ((signed char) 0x80000 == b) +
         ((long) 0x80000 == (unsigned long) b) +
         ((int) 0x80000 == (unsigned int) b) +
         ((short) 0x80000 == (unsigned short) b) +
         ((signed char) 0x80000 == (unsigned char) b) +
         (0x80000 < (unsigned long) b) +
         (0x80000 < (unsigned int) b) +
         (0x80000 < (unsigned short) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned short' is always false}}
         (0x80000 < (unsigned char) b) + // expected-warning {{comparison of constant 524288 with expression of type 'unsigned char' is always false}}
         ((long) 0x80000 < b) +
         ((int) 0x80000 < b) +
         ((short) 0x80000 < b) +
         ((signed char) 0x80000 < b) +
         ((long) 0x80000 < (unsigned long) b) +
         ((int) 0x80000 < (unsigned int) b) +
         ((short) 0x80000 < (unsigned short) b) +
         ((signed char) 0x80000 < (unsigned char) b) +

         // (a,0x80000)
         (a == (unsigned long) 0x80000) +
         (a == (unsigned int) 0x80000) +
         (a == (unsigned short) 0x80000) +
         (a == (unsigned char) 0x80000) +
         ((long) a == 0x80000) +
         ((int) a == 0x80000) +
         ((short) a == 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'short' is always false}}
         ((signed char) a == 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'signed char' is always false}}
         ((long) a == (unsigned long) 0x80000) +
         ((int) a == (unsigned int) 0x80000) +
         ((short) a == (unsigned short) 0x80000) +
         ((signed char) a == (unsigned char) 0x80000) +
         (a < (unsigned long) 0x80000) +  // expected-warning {{comparison of integers of different signs}}
         (a < (unsigned int) 0x80000) +
         (a < (unsigned short) 0x80000) +
         (a < (unsigned char) 0x80000) +
         ((long) a < 0x80000) +
         ((int) a < 0x80000) +
         ((short) a < 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'short' is always true}}
         ((signed char) a < 0x80000) + // expected-warning {{comparison of constant 524288 with expression of type 'signed char' is always true}}
         ((long) a < (unsigned long) 0x80000) +  // expected-warning {{comparison of integers of different signs}}
         ((int) a < (unsigned int) 0x80000) +  // expected-warning {{comparison of integers of different signs}}
         ((short) a < (unsigned short) 0x80000) +
         ((signed char) a < (unsigned char) 0x80000) +

         // We should be able to avoid warning about this.
         (b != (a < 4 ? 1 : 2)) +

         10
    ;
}

int equal(char *a, const char *b) {
    return a == b;
}

int arrays(char (*a)[5], char(*b)[10], char(*c)[5]) {
  int d = (a == c);
  return a == b; // expected-warning {{comparison of distinct pointer types}}
}

int pointers(int *a) {
  return a > 0; // expected-warning {{ordered comparison between pointer and zero ('int *' and 'int') is an extension}}
  return a > 42; // expected-warning {{ordered comparison between pointer and integer ('int *' and 'int')}}
  return a > (void *)0; // expected-warning {{comparison of distinct pointer types}}
}

int function_pointers(int (*a)(int), int (*b)(int), void (*c)(int)) {
  return a > b; // expected-warning {{ordered comparison of function pointers}}
  return function_pointers > function_pointers; // expected-warning {{self-comparison always evaluates to false}} expected-warning{{ordered comparison of function pointers}}
  return a > c; // expected-warning {{comparison of distinct pointer types}}
  return a == (void *) 0;
  return a == (void *) 1; // expected-warning {{equality comparison between function pointer and void pointer}}
}

int void_pointers(void* foo) {
  return foo == (void*) 0;
  return foo == (void*) 1;
}


int test1(int i) {
  enum en { zero };
  return i > zero;
}

// PR5937
int test2(int i32) {
  struct foo {
    unsigned int u8 : 8;
    unsigned long long u31 : 31;
    unsigned long long u32 : 32;
    unsigned long long u63 : 63;
    unsigned long long u64 : 64;
  } *x;
  
  if (x->u8 == i32) { // comparison in int32, exact
    return 0;
  } else if (x->u31 == i32) { // comparison in int32, exact
    return 1;
  } else if (x->u32 == i32) { // expected-warning {{comparison of integers of different signs}}
    return 2;
  } else if (x->u63 == i32) { // comparison in uint64, exact because ==
    return 3;
  } else if (x->u64 == i32) { // expected-warning {{comparison of integers of different signs}}
    return 4;
  } else {
    return 5;
  }
}

// PR5887
void test3() {
  unsigned short x, y;
  unsigned int z;
  if ((x > y ? x : y) > z)
    (void) 0;
}

// PR5961
extern char *ptr4;
void test4() {
  long value;
  if (value < (unsigned long) &ptr4) // expected-warning {{comparison of integers of different signs}}
    return;
}

// PR4807
int test5(unsigned int x) {
  return (x < 0) // expected-warning {{comparison of unsigned expression < 0 is always false}}
    && (0 > x)   // expected-warning {{comparison of 0 > unsigned expression is always false}}
    && (x >= 0)  // expected-warning {{comparison of unsigned expression >= 0 is always true}}
    && (0 <= x); // expected-warning {{comparison of 0 <= unsigned expression is always true}}
}

int test6(unsigned i, unsigned power) {
  unsigned x = (i < (1 << power) ? i : 0);
  return x != 3 ? 1 << power : i;
}

// <rdar://problem/8414119> enum >= (enum)0 comparison should not generate any warnings
enum rdar8414119_Vals { X, Y, Z };
#define ZERO 0
#define CHECK(x) (x >= X)
void rdar8414119_foo(enum rdar8414119_Vals v) {
  if (CHECK(v)) // no-warning
   return;
  if (v >= X) // no-warning
   return;
}
int rdar8414119_bar(unsigned x) {
  return x >= ZERO; // no-warning
}
#undef ZERO
#undef CHECK

int rdar8511238() {
  enum A { A_foo, A_bar };
  enum A a;

  if (a == 0)
      return 0;
  if (a != 0)
      return 0;
  if (a < 0) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
      return 0;
  if (a <= 0)
      return 0;
  if (a > 0)
      return 0;
  if (a >= 0) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
      return 0;

  if (0 == a)
      return 0;
  if (0 != a)
      return 0;
  if (0 < a)
      return 0;
  if (0 <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
      return 0;
  if (0 > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
      return 0;
  if (0 >= a)
      return 0;

  if (a == 0U)
      return 0;
  if (a != 0U)
      return 0;
  if (a < 0U) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
      return 0;
  if (a <= 0U)
      return 0;
  if (a > 0U)
      return 0;
  if (a >= 0U) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
      return 0;

  if (0U == a)
      return 0;
  if (0U != a)
      return 0;
  if (0U < a)
      return 0;
  if (0U <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
      return 0;
  if (0U > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
      return 0;
  if (0U >= a)
      return 0;

  return 20;
}

// PR10336
int test9(int sv, unsigned uv, long slv) {
  return sv == (uv ^= slv); // expected-warning {{comparison of integers of different signs: 'int' and 'unsigned int'}}
}

void test10(void) {
  int si;
  unsigned int ui;
  long sl;

  _Bool b;
  b = (si == (ui = sl)); // expected-warning {{comparison of integers of different signs: 'int' and 'unsigned int'}}
  b = (si == (ui = sl&15));
}

// PR11572
struct test11S { unsigned x : 30; };
int test11(unsigned y, struct test11S *p) {
  return y > (p->x >> 24); // no-warning
}

typedef char one_char[1];
typedef char two_chars[2];

void test12(unsigned a) {
  if (0 && -1 > a) { }
}

// PR36008

enum PR36008EnumTest {
  kPR36008Value = 0,
};

void pr36008(enum PR36008EnumTest lhs) {
  __typeof__(lhs) x = lhs;
  __typeof__(kPR36008Value) y = (kPR36008Value);
  if (x == y) x = y; // no warning
  if (y == x) y = x; // no warning
}