106 lines
4.0 KiB
C++
106 lines
4.0 KiB
C++
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wno-unused %s
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int f(int, int);
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struct A {
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int x, y;
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};
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struct S {
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S(int, int);
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};
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void test() {
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int a;
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int xs[10];
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++a = 0; // ok
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a + ++a; // expected-warning {{unsequenced modification and access to 'a'}}
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a = ++a; // ok
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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; // ok
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(a++, a++); // ok
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++a + ++a; // expected-warning {{multiple unsequenced modifications to 'a'}}
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a++ + a++; // expected-warning {{multiple unsequenced modifications}}
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(a++, a) = 0; // ok, increment is sequenced before value computation of LHS
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a = xs[++a]; // ok
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a = xs[a++]; // expected-warning {{multiple unsequenced modifications}}
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(a ? xs[0] : xs[1]) = ++a; // expected-warning {{unsequenced modification and access}}
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a = (++a, ++a); // ok
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a = (a++, ++a); // ok
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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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// Compound assignment "A OP= B" is equivalent to "A = A OP B" except that A
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// is evaluated only once.
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(++a, a) = 1; // ok
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(++a, a) += 1; // ok
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a = ++a; // ok
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a += ++a; // expected-warning {{unsequenced modification and access}}
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A agg1 = { a++, a++ }; // ok
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A agg2 = { a++ + a, a++ }; // expected-warning {{unsequenced modification and access}}
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S str1(a++, a++); // expected-warning {{multiple unsequenced modifications}}
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S str2 = { a++, a++ }; // ok
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S str3 = { 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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(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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(a -= 128) &= 128; // ok
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++a += 1; // 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_object_size(&(++a, a), 0) ? 1 : 0) + ++a; // ok
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(__builtin_expect(++a, 0) ? 1 : 0) + ++a; // expected-warning {{multiple unsequenced modifications}}
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}
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