1418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -Wno-unused %s 2418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 3418dd3eb3e813235af089b5c88182941f8a03d20Richard Smithint f(int, int); 4418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 5418dd3eb3e813235af089b5c88182941f8a03d20Richard Smithtypedef struct A { 6418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith int x, y; 7418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith} A; 8418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 9418dd3eb3e813235af089b5c88182941f8a03d20Richard Smithvoid test() { 10418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith int a; 11418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith int xs[10]; 12418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a + ++a; // expected-warning {{unsequenced modification and access to 'a'}} 13418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = ++a; // expected-warning {{multiple unsequenced modifications to 'a'}} 14418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a + a++; // expected-warning {{unsequenced modification and access to 'a'}} 15418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = a++; // expected-warning {{multiple unsequenced modifications to 'a'}} 16418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (a++, a++); // ok 17418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith ++a + ++a; // expected-warning {{multiple unsequenced modifications}} 18418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a++ + a++; // expected-warning {{multiple unsequenced modifications}} 19418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = xs[++a]; // expected-warning {{multiple unsequenced modifications}} 20418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = xs[a++]; // expected-warning {{multiple unsequenced modifications}} 21418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = (++a, ++a); // expected-warning {{multiple unsequenced modifications}} 22418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = (a++, ++a); // expected-warning {{multiple unsequenced modifications}} 23418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = (a++, a++); // expected-warning {{multiple unsequenced modifications}} 24418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith f(a, a); // ok 25418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith f(a = 0, a); // expected-warning {{unsequenced modification and access}} 26418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith f(a, a += 0); // expected-warning {{unsequenced modification and access}} 27418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith f(a = 0, a = 0); // expected-warning {{multiple unsequenced modifications}} 280c0b3909d11de7440d77556089516918b9c04cefRichard Smith a = f(++a, 0); // ok 290c0b3909d11de7440d77556089516918b9c04cefRichard Smith a = f(a++, 0); // ok 300c0b3909d11de7440d77556089516918b9c04cefRichard Smith a = f(++a, a++); // expected-warning {{multiple unsequenced modifications}} 31418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 320e2c34f92f00628d48968dfea096d36381f494cbStephen Hines ++a + f(++a, 0); // expected-warning {{multiple unsequenced modifications}} 330e2c34f92f00628d48968dfea096d36381f494cbStephen Hines f(++a, 0) + ++a; // expected-warning {{multiple unsequenced modifications}} 340e2c34f92f00628d48968dfea096d36381f494cbStephen Hines a++ + f(a++, 0); // expected-warning {{multiple unsequenced modifications}} 350e2c34f92f00628d48968dfea096d36381f494cbStephen Hines f(a++, 0) + a++; // expected-warning {{multiple unsequenced modifications}} 360e2c34f92f00628d48968dfea096d36381f494cbStephen Hines 37418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = ++a; // expected-warning {{multiple unsequenced modifications}} 38418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a += ++a; // expected-warning {{unsequenced modification and access}} 39418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 40418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith A agg1 = { a++, a++ }; // expected-warning {{multiple unsequenced modifications}} 41418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith A agg2 = { a++ + a, a++ }; // expected-warning {{unsequenced modification and access}} 42418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 43418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (xs[2] && (a = 0)) + a; // ok 44418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (0 && (a = 0)) + a; // ok 45418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (1 && (a = 0)) + a; // expected-warning {{unsequenced modification and access}} 46418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 47418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (xs[3] || (a = 0)) + a; // ok 48418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (0 || (a = 0)) + a; // expected-warning {{unsequenced modification and access}} 49418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (1 || (a = 0)) + a; // ok 50418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 51418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (xs[4] ? a : ++a) + a; // ok 52418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (0 ? a : ++a) + a; // expected-warning {{unsequenced modification and access}} 53418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (1 ? a : ++a) + a; // ok 54418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (xs[5] ? ++a : ++a) + a; // FIXME: warn here 55418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 560e2c34f92f00628d48968dfea096d36381f494cbStephen Hines (++a, xs[6] ? ++a : 0) + a; // expected-warning {{unsequenced modification and access}} 57418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 58418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // Here, the read of the fourth 'a' might happen before or after the write to 59418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // the second 'a'. 60418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a += (a++, a) + a; // expected-warning {{unsequenced modification and access}} 61418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 62418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith int *p = xs; 63418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = *(a++, p); // ok 64418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = a++ && a; // ok 65418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 66418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith A *q = &agg1; 67418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (q = &agg2)->y = q->x; // expected-warning {{unsequenced modification and access to 'q'}} 68418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 69418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // This has undefined behavior if a == 0; otherwise, the side-effect of the 70418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // increment is sequenced before the value computation of 'f(a, a)', which is 71418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // sequenced before the value computation of the '&&', which is sequenced 72418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // before the assignment. We treat the sequencing in '&&' as being 73418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // unconditional. 74418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith a = a++ && f(a, a); 75418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 76418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith // This has undefined behavior if a != 0. FIXME: We should diagnose this. 77418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (a && a++) + a; 78418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 79418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (xs[7] && ++a) * (!xs[7] && ++a); // ok 80418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 81418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith xs[0] = (a = 1, a); // ok 82418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 83418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith xs[8] ? ++a + a++ : 0; // expected-warning {{multiple unsequenced modifications}} 84418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith xs[8] ? 0 : ++a + a++; // expected-warning {{multiple unsequenced modifications}} 85418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith xs[8] ? ++a : a++; // ok 86418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 87418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith xs[8] && (++a + a++); // expected-warning {{multiple unsequenced modifications}} 88418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith xs[8] || (++a + a++); // expected-warning {{multiple unsequenced modifications}} 89418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith 90418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (__builtin_classify_type(++a) ? 1 : 0) + ++a; // ok 91418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith (__builtin_constant_p(++a) ? 1 : 0) + ++a; // ok 920e2c34f92f00628d48968dfea096d36381f494cbStephen Hines (__builtin_expect(++a, 0) ? 1 : 0) + ++a; // expected-warning {{multiple unsequenced modifications}} 930e2c34f92f00628d48968dfea096d36381f494cbStephen Hines _Generic(++a, default: 0) + ++a; // ok 940e2c34f92f00628d48968dfea096d36381f494cbStephen Hines sizeof(++a) + ++a; // ok 950e2c34f92f00628d48968dfea096d36381f494cbStephen Hines _Alignof(++a) + ++a; // expected-warning {{extension}} 96418dd3eb3e813235af089b5c88182941f8a03d20Richard Smith} 97