msg_169.c revision 1.2
1 1.2 rillig /* $NetBSD: msg_169.c,v 1.2 2021/01/04 15:52:51 rillig Exp $ */ 2 1.1 rillig # 3 "msg_169.c" 3 1.1 rillig 4 1.1 rillig // Test for message: precedence confusion possible: parenthesize! [169] 5 1.1 rillig 6 1.2 rillig /* lint1-flags: -g -h -S -w */ 7 1.2 rillig 8 1.2 rillig typedef _Bool bool; 9 1.2 rillig 10 1.2 rillig void 11 1.2 rillig confusing_shift_arith(unsigned a, unsigned b, unsigned c, unsigned char ch) 12 1.2 rillig { 13 1.2 rillig unsigned con, okl, okr; 14 1.2 rillig 15 1.2 rillig con = a + b << c; 16 1.2 rillig okl = (a + b) << c; 17 1.2 rillig okr = a + (b << c); 18 1.2 rillig 19 1.2 rillig con = a << b + c; 20 1.2 rillig okl = (a << b) + c; 21 1.2 rillig okr = a << (b + c); 22 1.2 rillig 23 1.2 rillig con = a - b >> c; 24 1.2 rillig okl = (a - b) >> c; 25 1.2 rillig okr = a - (b >> c); 26 1.2 rillig 27 1.2 rillig con = a >> b - c; 28 1.2 rillig okl = (a >> b) - c; 29 1.2 rillig okr = a >> (b - c); 30 1.2 rillig 31 1.2 rillig // Parenthesizing the inner operands has no effect on the warning. 32 1.2 rillig con = (a) + b << c; 33 1.2 rillig con = a + (b) << c; 34 1.2 rillig con = a + b << (c); 35 1.2 rillig 36 1.2 rillig // The usual arithmetic promotions have no effect on the warning. 37 1.2 rillig con = ch + b << c; 38 1.2 rillig con = a + ch << c; 39 1.2 rillig con = a + b << ch; 40 1.2 rillig } 41 1.2 rillig 42 1.2 rillig void 43 1.2 rillig confusing_logical(bool a, bool b, bool c) 44 1.2 rillig { 45 1.2 rillig bool con, okl, okr, eql; 46 1.2 rillig 47 1.2 rillig eql = a && b && c; 48 1.2 rillig eql = a || b || c; 49 1.2 rillig 50 1.2 rillig con = a && b || c; 51 1.2 rillig okl = (a && b) || c; 52 1.2 rillig okr = a && (b || c); 53 1.2 rillig 54 1.2 rillig con = a || b && c; 55 1.2 rillig okl = (a || b) && c; 56 1.2 rillig okr = a || (b && c); 57 1.2 rillig } 58 1.2 rillig 59 1.2 rillig void 60 1.2 rillig confusing_bitwise(unsigned a, unsigned b, unsigned c) 61 1.2 rillig { 62 1.2 rillig bool con, okl, okr, eql; 63 1.2 rillig 64 1.2 rillig eql = a & b & c; 65 1.2 rillig eql = a | b | c; 66 1.2 rillig eql = a ^ b ^ c; 67 1.2 rillig 68 1.2 rillig con = a | b ^ c; 69 1.2 rillig okl = (a | b) ^ c; 70 1.2 rillig okr = a | (b ^ c); 71 1.2 rillig 72 1.2 rillig con = a | b & c; 73 1.2 rillig okl = (a | b) & c; 74 1.2 rillig okr = a | (b & c); 75 1.2 rillig 76 1.2 rillig con = a ^ b | c; 77 1.2 rillig okl = (a ^ b) | c; 78 1.2 rillig okr = a ^ (b | c); 79 1.2 rillig 80 1.2 rillig con = a ^ b & c; 81 1.2 rillig okl = (a ^ b) & c; 82 1.2 rillig okr = a ^ (b & c); 83 1.2 rillig 84 1.2 rillig con = a & b | c; 85 1.2 rillig okl = (a & b) ^ c; 86 1.2 rillig okr = a & (b ^ c); 87 1.2 rillig 88 1.2 rillig con = a & b ^ c; 89 1.2 rillig okl = (a & b) ^ c; 90 1.2 rillig okr = a & (b ^ c); 91 1.2 rillig 92 1.2 rillig con = a & b + c; 93 1.2 rillig okl = (a & b) + c; 94 1.2 rillig okr = a & (b + c); 95 1.2 rillig 96 1.2 rillig con = a - b | c; 97 1.2 rillig okl = (a - b) | c; 98 1.2 rillig okr = a - (b | c); 99 1.2 rillig 100 1.2 rillig // This looks like a binomial formula but isn't. 101 1.2 rillig con = a ^ 2 - 2 * a * b + b ^ 2; 102 1.2 rillig 103 1.2 rillig // This isn't a binomial formula either since '^' means xor. 104 1.2 rillig con = (a ^ 2) - 2 * a * b + (b ^ 2); 105 1.2 rillig } 106 1.2 rillig 107 1.2 rillig void 108 1.2 rillig constant_expressions(void) 109 1.2 rillig { 110 1.2 rillig unsigned con; 111 1.2 rillig 112 1.2 rillig // The check for confusing precedence happens after constant folding. 113 1.2 rillig // Therefore the following lines do not generate warnings. 114 1.2 rillig con = 1 & 2 | 3; 115 1.2 rillig con = 4 << 5 + 6; 116 1.2 rillig con = 7 ^ 8 & 9; 117 1.2 rillig } 118 1.2 rillig 119 1.2 rillig void 120 1.2 rillig cast_expressions(char a, char b, char c) 121 1.2 rillig { 122 1.2 rillig unsigned con; 123 1.2 rillig 124 1.2 rillig // Adding casts to the leaf nodes doesn't change anything about the 125 1.2 rillig // confusing precedence. 126 1.2 rillig con = (unsigned)a | (unsigned)b & (unsigned)c; 127 1.2 rillig con = (unsigned)a & (unsigned)b | (unsigned)c; 128 1.2 rillig 129 1.2 rillig // Adding a cast around the whole calculation doesn't change the 130 1.2 rillig // precedence as well. 131 1.2 rillig con = (unsigned)(a | b & c); 132 1.2 rillig 133 1.2 rillig // Adding a cast around an intermediate result groups the operands 134 1.2 rillig // of the main node, which prevents any confusion about precedence. 135 1.2 rillig con = (unsigned)a | (unsigned)(b & c); 136 1.2 rillig con = a | (unsigned)(b & c); 137 1.2 rillig con = (unsigned)(a | b) & (unsigned)c; 138 1.2 rillig con = (unsigned)(a | b) & c; 139 1.2 rillig } 140 1.2 rillig 141 1.2 rillig void 142 1.2 rillig expected_precedence(int a, int b, int c) 143 1.2 rillig { 144 1.2 rillig int ok; 145 1.2 rillig 146 1.2 rillig ok = a + b * c; 147 1.2 rillig } 148 1.2 rillig 149 1.2 rillig // TODO: add a test with unsigned long instead of unsigned, to demonstrate 150 1.2 rillig // that the typo in 151
Indexes created Wed Oct 01 19:09:53 GMT 2025