| // RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -Wno-unused %s |
| |
| int f(int, int); |
| |
| typedef struct A { |
| int x, y; |
| } A; |
| |
| void test() { |
| int a; |
| int xs[10]; |
| a + ++a; // expected-warning {{unsequenced modification and access to 'a'}} |
| a = ++a; // expected-warning {{multiple unsequenced modifications to 'a'}} |
| a + a++; // expected-warning {{unsequenced modification and access to 'a'}} |
| a = a++; // expected-warning {{multiple unsequenced modifications to 'a'}} |
| (a++, a++); // ok |
| ++a + ++a; // expected-warning {{multiple unsequenced modifications}} |
| a++ + a++; // expected-warning {{multiple unsequenced modifications}} |
| a = xs[++a]; // expected-warning {{multiple unsequenced modifications}} |
| a = xs[a++]; // expected-warning {{multiple unsequenced modifications}} |
| a = (++a, ++a); // expected-warning {{multiple unsequenced modifications}} |
| a = (a++, ++a); // expected-warning {{multiple unsequenced modifications}} |
| a = (a++, a++); // expected-warning {{multiple unsequenced modifications}} |
| f(a, a); // ok |
| f(a = 0, a); // expected-warning {{unsequenced modification and access}} |
| f(a, a += 0); // expected-warning {{unsequenced modification and access}} |
| f(a = 0, a = 0); // expected-warning {{multiple unsequenced modifications}} |
| a = f(++a, 0); // ok |
| a = f(a++, 0); // ok |
| a = f(++a, a++); // expected-warning {{multiple unsequenced modifications}} |
| |
| ++a + f(++a, 0); // expected-warning {{multiple unsequenced modifications}} |
| f(++a, 0) + ++a; // expected-warning {{multiple unsequenced modifications}} |
| a++ + f(a++, 0); // expected-warning {{multiple unsequenced modifications}} |
| f(a++, 0) + a++; // expected-warning {{multiple unsequenced modifications}} |
| |
| a = ++a; // expected-warning {{multiple unsequenced modifications}} |
| a += ++a; // expected-warning {{unsequenced modification and access}} |
| |
| A agg1 = { a++, a++ }; // expected-warning {{multiple unsequenced modifications}} |
| A agg2 = { a++ + a, a++ }; // expected-warning {{unsequenced modification and access}} |
| |
| (xs[2] && (a = 0)) + a; // expected-warning {{unsequenced modification and access to 'a'}} |
| (0 && (a = 0)) + a; // ok |
| (1 && (a = 0)) + a; // expected-warning {{unsequenced modification and access}} |
| |
| (xs[3] || (a = 0)) + a; // expected-warning {{unsequenced modification and access to 'a'}} |
| (0 || (a = 0)) + a; // expected-warning {{unsequenced modification and access}} |
| (1 || (a = 0)) + a; // ok |
| |
| (xs[4] ? a : ++a) + a; // expected-warning {{unsequenced modification and access to 'a'}} |
| (0 ? a : ++a) + a; // expected-warning {{unsequenced modification and access}} |
| (1 ? a : ++a) + a; // ok |
| (xs[5] ? ++a : ++a) + a; // expected-warning {{unsequenced modification and access to 'a'}} |
| |
| (++a, xs[6] ? ++a : 0) + a; // expected-warning {{unsequenced modification and access}} |
| |
| // Here, the read of the fourth 'a' might happen before or after the write to |
| // the second 'a'. |
| a += (a++, a) + a; // expected-warning {{unsequenced modification and access}} |
| |
| int *p = xs; |
| a = *(a++, p); // ok |
| a = a++ && a; // ok |
| |
| A *q = &agg1; |
| (q = &agg2)->y = q->x; // expected-warning {{unsequenced modification and access to 'q'}} |
| |
| // This has undefined behavior if a == 0; otherwise, the side-effect of the |
| // increment is sequenced before the value computation of 'f(a, a)', which is |
| // sequenced before the value computation of the '&&', which is sequenced |
| // before the assignment. We treat the sequencing in '&&' as being |
| // unconditional. |
| a = a++ && f(a, a); |
| |
| // This has undefined behavior if a != 0. |
| (a && a++) + a; // expected-warning {{unsequenced modification and access to 'a'}} |
| |
| // FIXME: Find a way to avoid warning here. |
| (xs[7] && ++a) * (!xs[7] && ++a); // expected-warning {{multiple unsequenced modifications to 'a'}} |
| |
| xs[0] = (a = 1, a); // ok |
| |
| xs[8] ? ++a + a++ : 0; // expected-warning {{multiple unsequenced modifications}} |
| xs[8] ? 0 : ++a + a++; // expected-warning {{multiple unsequenced modifications}} |
| xs[8] ? ++a : a++; // ok |
| |
| xs[8] && (++a + a++); // expected-warning {{multiple unsequenced modifications}} |
| xs[8] || (++a + a++); // expected-warning {{multiple unsequenced modifications}} |
| |
| (__builtin_classify_type(++a) ? 1 : 0) + ++a; // ok |
| (__builtin_constant_p(++a) ? 1 : 0) + ++a; // ok |
| (__builtin_expect(++a, 0) ? 1 : 0) + ++a; // expected-warning {{multiple unsequenced modifications}} |
| _Generic(++a, default: 0) + ++a; // ok |
| sizeof(++a) + ++a; // ok |
| _Alignof(++a) + ++a; // expected-warning {{extension}} |
| |
| __builtin_constant_p(f(++a, 0)) ? f(f(++a, 0), f(++a, 0)) : 0; |
| |
| if (0) ++a + ++a; // ok, unreachable |
| } |
| |
| void g(const char *p, int n) { |
| // This resembles code produced by some macros in glibc's <string.h>. |
| __builtin_constant_p(p) && __builtin_constant_p(++n) && (++n + ++n); |
| } |