| 1 | // RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -Wno-unused %s |
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| 2 | |
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| 3 | int f(int, int); |
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| 4 | |
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| 5 | typedef struct A { |
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| 6 | int x, y; |
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| 7 | } A; |
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| 8 | |
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| 9 | void test() { |
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| 10 | int a; |
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| 11 | int xs[10]; |
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| 12 | a + ++a; // expected-warning {{unsequenced modification and access to 'a'}} |
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| 13 | a = ++a; // expected-warning {{multiple unsequenced modifications to 'a'}} |
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| 14 | a + a++; // expected-warning {{unsequenced modification and access to 'a'}} |
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| 15 | a = a++; // expected-warning {{multiple unsequenced modifications to 'a'}} |
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| 16 | (a++, a++); // ok |
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| 17 | ++a + ++a; // expected-warning {{multiple unsequenced modifications}} |
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| 18 | a++ + a++; // expected-warning {{multiple unsequenced modifications}} |
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| 19 | a = xs[++a]; // expected-warning {{multiple unsequenced modifications}} |
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| 20 | a = xs[a++]; // expected-warning {{multiple unsequenced modifications}} |
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| 21 | a = (++a, ++a); // expected-warning {{multiple unsequenced modifications}} |
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| 22 | a = (a++, ++a); // expected-warning {{multiple unsequenced modifications}} |
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| 23 | a = (a++, a++); // expected-warning {{multiple unsequenced modifications}} |
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| 24 | f(a, a); // ok |
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| 25 | f(a = 0, a); // expected-warning {{unsequenced modification and access}} |
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| 26 | f(a, a += 0); // expected-warning {{unsequenced modification and access}} |
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| 27 | f(a = 0, a = 0); // expected-warning {{multiple unsequenced modifications}} |
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| 28 | a = f(++a, 0); // ok |
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| 29 | a = f(a++, 0); // ok |
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| 30 | a = f(++a, a++); // expected-warning {{multiple unsequenced modifications}} |
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| 31 | |
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| 32 | ++a + f(++a, 0); // expected-warning {{multiple unsequenced modifications}} |
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| 33 | f(++a, 0) + ++a; // expected-warning {{multiple unsequenced modifications}} |
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| 34 | a++ + f(a++, 0); // expected-warning {{multiple unsequenced modifications}} |
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| 35 | f(a++, 0) + a++; // expected-warning {{multiple unsequenced modifications}} |
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| 36 | |
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| 37 | a = ++a; // expected-warning {{multiple unsequenced modifications}} |
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| 38 | a += ++a; // expected-warning {{unsequenced modification and access}} |
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| 39 | |
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| 40 | A agg1 = { a++, a++ }; // expected-warning {{multiple unsequenced modifications}} |
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| 41 | A agg2 = { a++ + a, a++ }; // expected-warning {{unsequenced modification and access}} |
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| 42 | |
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| 43 | (xs[2] && (a = 0)) + a; // ok |
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| 44 | (0 && (a = 0)) + a; // ok |
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| 45 | (1 && (a = 0)) + a; // expected-warning {{unsequenced modification and access}} |
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| 46 | |
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| 47 | (xs[3] || (a = 0)) + a; // ok |
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| 48 | (0 || (a = 0)) + a; // expected-warning {{unsequenced modification and access}} |
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| 49 | (1 || (a = 0)) + a; // ok |
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| 50 | |
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| 51 | (xs[4] ? a : ++a) + a; // ok |
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| 52 | (0 ? a : ++a) + a; // expected-warning {{unsequenced modification and access}} |
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| 53 | (1 ? a : ++a) + a; // ok |
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| 54 | (xs[5] ? ++a : ++a) + a; // FIXME: warn here |
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| 55 | |
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| 56 | (++a, xs[6] ? ++a : 0) + a; // expected-warning {{unsequenced modification and access}} |
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| 57 | |
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| 58 | // Here, the read of the fourth 'a' might happen before or after the write to |
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| 59 | // the second 'a'. |
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| 60 | a += (a++, a) + a; // expected-warning {{unsequenced modification and access}} |
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| 61 | |
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| 62 | int *p = xs; |
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| 63 | a = *(a++, p); // ok |
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| 64 | a = a++ && a; // ok |
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| 65 | |
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| 66 | A *q = &agg1; |
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| 67 | (q = &agg2)->y = q->x; // expected-warning {{unsequenced modification and access to 'q'}} |
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| 68 | |
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| 69 | // This has undefined behavior if a == 0; otherwise, the side-effect of the |
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| 70 | // increment is sequenced before the value computation of 'f(a, a)', which is |
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| 71 | // sequenced before the value computation of the '&&', which is sequenced |
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| 72 | // before the assignment. We treat the sequencing in '&&' as being |
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| 73 | // unconditional. |
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| 74 | a = a++ && f(a, a); |
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| 75 | |
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| 76 | // This has undefined behavior if a != 0. FIXME: We should diagnose this. |
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| 77 | (a && a++) + a; |
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| 78 | |
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| 79 | (xs[7] && ++a) * (!xs[7] && ++a); // ok |
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| 80 | |
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| 81 | xs[0] = (a = 1, a); // ok |
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| 82 | |
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| 83 | xs[8] ? ++a + a++ : 0; // expected-warning {{multiple unsequenced modifications}} |
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| 84 | xs[8] ? 0 : ++a + a++; // expected-warning {{multiple unsequenced modifications}} |
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| 85 | xs[8] ? ++a : a++; // ok |
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| 86 | |
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| 87 | xs[8] && (++a + a++); // expected-warning {{multiple unsequenced modifications}} |
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| 88 | xs[8] || (++a + a++); // expected-warning {{multiple unsequenced modifications}} |
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| 89 | |
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| 90 | (__builtin_classify_type(++a) ? 1 : 0) + ++a; // ok |
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| 91 | (__builtin_constant_p(++a) ? 1 : 0) + ++a; // ok |
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| 92 | (__builtin_expect(++a, 0) ? 1 : 0) + ++a; // expected-warning {{multiple unsequenced modifications}} |
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| 93 | _Generic(++a, default: 0) + ++a; // ok |
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| 94 | sizeof(++a) + ++a; // ok |
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| 95 | _Alignof(++a) + ++a; // expected-warning {{extension}} |
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| 96 | } |
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| 97 | |
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