30 lines · c
1// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c11 -isystem %S/Inputs2// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c11 -isystem %S/Inputs3// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c11 -isystem %S/Inputs -Wsystem-headers -DSYSTEM_WARNINGS4// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c11 -isystem %S/Inputs -Wsystem-headers -DSYSTEM_WARNINGS5 6#include <pointer-subtraction.h>7 8void a(void) {9 char *f = (char *)0;10 f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}11 f = (char *)(f - (char *)0); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}12 f = (char *)((char *)0 - (char *)0); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}} expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}13 14 if (1)15 f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}16 else17 f = (char *)((char *)0 - f);18 19 if (0)20 f = (char *)((char *)0 - f);21 else22 f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}23 24#ifndef SYSTEM_WARNINGS25 SYSTEM_MACRO(f);26#else27 SYSTEM_MACRO(f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}28#endif29}30