forked from OSchip/llvm-project
				
			
		
			
				
	
	
		
			107 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			107 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			C
		
	
	
	
| // RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -Wno-unused %s
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| 
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| int f(int, int);
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| 
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| typedef struct A {
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|   int x, y;
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| } A;
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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 + ++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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| 
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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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| 
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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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| 
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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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| 
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|   (xs[2] && (a = 0)) + a; // expected-warning {{unsequenced modification and access to 'a'}}
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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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| 
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|   (xs[3] || (a = 0)) + a; // expected-warning {{unsequenced modification and access to 'a'}}
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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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| 
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|   (xs[4] ? a : ++a) + a; // expected-warning {{unsequenced modification and access to 'a'}}
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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; // expected-warning {{unsequenced modification and access to 'a'}}
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| 
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|   (++a, xs[6] ? ++a : 0) + a; // expected-warning {{unsequenced modification and access}}
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|   // This has undefined behavior if a != 0.
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|   (a && a++) + a; // expected-warning {{unsequenced modification and access to 'a'}}
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| 
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|   // FIXME: Find a way to avoid warning here.
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|   (xs[7] && ++a) * (!xs[7] && ++a); // expected-warning {{multiple unsequenced modifications to 'a'}}
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| 
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|   xs[0] = (a = 1, a); // ok
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| 
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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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| 
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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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| 
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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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| 
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|   __builtin_constant_p(f(++a, 0)) ? f(f(++a, 0), f(++a, 0)) : 0;
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| 
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|   if (0) ++a + ++a; // ok, unreachable
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| }
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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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