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