llvm / llvm-project / 98dbcff19cfedb4e27d267310a76d616cd435447 / . / clang / test / Sema / warn-overlap.c

// RUN: %clang_cc1 -fsyntax-only -verify -Wtautological-overlap-compare %s | |

// RUN: %clang_cc1 -fsyntax-only -verify -Wall -Wno-unused -Wno-loop-analysis %s | |

#define mydefine 2 | |

enum Choices { | |

CHOICE_0 = 0, | |

CHOICE_1 = 1 | |

}; | |

enum Unchoices { | |

UNCHOICE_0 = 0, | |

UNCHOICE_1 = 1 | |

}; | |

void f(int x) { | |

int y = 0; | |

// > || < | |

if (x > 2 || x < 1) { } | |

if (x > 2 || x < 2) { } | |

if (x != 2 || x != 3) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x > 2 || x < 3) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x > 0 || x < 0) { } | |

if (x > 2 || x <= 1) { } | |

if (x > 2 || x <= 2) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x > 2 || x <= 3) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x >= 2 || x < 1) { } | |

if (x >= 2 || x < 2) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x >= 2 || x < 3) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x >= 2 || x <= 1) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x >= 2 || x <= 2) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x >= 2 || x <= 3) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x >= 0 || x <= 0) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

// > && < | |

if (x > 2 && x < 1) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x > 2 && x < 2) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x > 2 && x < 3) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x > 0 && x < 1) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x > 2 && x <= 1) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x > 2 && x <= 2) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x > 2 && x <= 3) { } | |

if (x >= 2 && x < 1) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x >= 2 && x < 2) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x >= 2 && x < 3) { } | |

if (x >= 0 && x < 0) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x >= 2 && x <= 1) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x >= 2 && x <= 2) { } | |

if (x >= 2 && x <= 3) { } | |

// !=, ==, .. | |

if (x != 2 || x != 3) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x != 2 || x < 3) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x == 2 && x == 3) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x == 2 && x > 3) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x == 3 && x < 0) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (3 == x && x < 0) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

if (x == mydefine && x > 3) { } | |

if (x == (mydefine + 1) && x > 3) { } | |

if (x != CHOICE_0 || x != CHOICE_1) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (x == CHOICE_0 && x == CHOICE_1) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

// Don't warn if comparing x to different types | |

if (x == CHOICE_0 && x == 1) { } | |

if (x != CHOICE_0 || x != 1) { } | |

// "Different types" includes different enums | |

if (x == CHOICE_0 && x == UNCHOICE_1) { } | |

if (x != CHOICE_0 || x != UNCHOICE_1) { } | |

} | |

void enums(enum Choices c) { | |

if (c != CHOICE_0 || c != CHOICE_1) { } // expected-warning {{overlapping comparisons always evaluate to true}} | |

if (c == CHOICE_0 && c == CHOICE_1) { } // expected-warning {{overlapping comparisons always evaluate to false}} | |

// Don't warn if comparing x to different types | |

if (c == CHOICE_0 && c == 1) { } | |

if (c != CHOICE_0 || c != 1) { } | |

// "Different types" includes different enums | |

if (c == CHOICE_0 && c == UNCHOICE_1) { } | |

if (c != CHOICE_0 || c != UNCHOICE_1) { } | |

} | |

// Don't generate a warning here. | |

void array_out_of_bounds() { | |

int x; | |

int buffer[4]; | |

x = (-7 > 0) ? (buffer[-7]) : 0; | |

} | |

void bool_contexts(int x) { | |

if (x > 4 || x < 10) {} | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

for (;x > 4 || x < 10;) {} | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

while (x > 4 || x < 10) {} | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

do {} while (x > 4 || x < 10); | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

x = (x > 4 || x < 10) ? 1 : 2; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

if ((void)5, x > 4 || x < 10) {} | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

} | |

void assignment(int x) { | |

int a = x > 4 || x < 10; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

int b = x < 2 && x > 5; | |

// expected-warning@-1{{overlapping comparisons always evaluate to false}} | |

int c = x != 1 || x != 3; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

int d = x == 1 && x == 2; | |

// expected-warning@-1{{overlapping comparisons always evaluate to false}} | |

int e = x < 1 || x != 0; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

} | |

int returns(int x) { | |

return x > 4 || x < 10; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

return x < 2 && x > 5; | |

// expected-warning@-1{{overlapping comparisons always evaluate to false}} | |

return x != 1 || x != 3; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

return x == 1 && x == 2; | |

// expected-warning@-1{{overlapping comparisons always evaluate to false}} | |

return x < 1 || x != 0; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

} | |

int integer_conversion(unsigned x, int y) { | |

return x > 4 || x < 10; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

return y > 4u || y < 10u; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

} | |

int negative_compare(int x) { | |

return x > -1 || x < 1; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

} | |

int no_warning(unsigned x) { | |

return x >= 0 || x == 1; | |

// no warning since "x >= 0" is caught by a different tautological warning. | |

} | |

struct A { | |

int x; | |

int y; | |

}; | |

int struct_test(struct A a) { | |

return a.x > 5 && a.y < 1; // no warning, different variables | |

return a.x > 5 && a.x < 1; | |

// expected-warning@-1{{overlapping comparisons always evaluate to false}} | |

return a.y == 1 || a.y != 1; | |

// expected-warning@-1{{overlapping comparisons always evaluate to true}} | |

} |