1 // RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-apple-darwin %s
2
3 // This file tests -Wconstant-conversion, a subcategory of -Wconversion
4 // which is on by default.
5
6 // rdar://problem/6792488
test_6792488(void)7 void test_6792488(void) {
8 int x = 0x3ff0000000000000U; // expected-warning {{implicit conversion from 'unsigned long' to 'int' changes value from 4607182418800017408 to 0}}
9 }
10
test_7809123(void)11 void test_7809123(void) {
12 struct { int i5 : 5; } a;
13
14 a.i5 = 36; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 36 to 4}}
15 }
16
test()17 void test() {
18 struct { int bit : 1; } a;
19 a.bit = 1; // shouldn't warn
20 }
21
22 enum Test2 { K_zero, K_one };
test2(enum Test2 * t)23 enum Test2 test2(enum Test2 *t) {
24 *t = 20;
25 return 10; // shouldn't warn
26 }
27
test3()28 void test3() {
29 struct A {
30 unsigned int foo : 2;
31 int bar : 2;
32 };
33
34 struct A a = { 0, 10 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to -2}}
35 struct A b[] = { 0, 10, 0, 0 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to -2}}
36 struct A c[] = {{10, 0}}; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to 2}}
37 struct A d = (struct A) { 10, 0 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to 2}}
38 struct A e = { .foo = 10 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to 2}}
39 }
40
test4()41 void test4() {
42 struct A {
43 char c : 2;
44 } a;
45
46 a.c = 0x101; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 257 to 1}}
47 }
48
test5()49 void test5() {
50 struct A {
51 _Bool b : 1;
52 } a;
53
54 // Don't warn about this implicit conversion to bool, or at least
55 // don't warn about it just because it's a bit-field.
56 a.b = 100;
57 }
58
test6()59 void test6() {
60 // Test that unreachable code doesn't trigger the truncation warning.
61 unsigned char x = 0 ? 65535 : 1; // no-warning
62 unsigned char y = 1 ? 65535 : 1; // expected-warning {{changes value}}
63 }
64
test7()65 void test7() {
66 struct {
67 unsigned int twoBits1:2;
68 unsigned int twoBits2:2;
69 unsigned int reserved:28;
70 } f;
71
72 f.twoBits1 = ~0; // no-warning
73 f.twoBits1 = ~1; // no-warning
74 f.twoBits2 = ~2; // expected-warning {{implicit truncation from 'int' to bit-field changes value from -3 to 1}}
75 f.twoBits1 &= ~1; // no-warning
76 f.twoBits2 &= ~2; // no-warning
77 }
78
test8()79 void test8() {
80 enum E { A, B, C };
81 struct { enum E x : 1; } f;
82 f.x = C; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 2 to 0}}
83 }
84
test9()85 void test9() {
86 const char max_char = 0x7F;
87 const short max_short = 0x7FFF;
88 const int max_int = 0x7FFFFFFF;
89
90 const short max_char_plus_one = (short)max_char + 1;
91 const int max_short_plus_one = (int)max_short + 1;
92 const long max_int_plus_one = (long)max_int + 1;
93
94 char new_char = max_char_plus_one; // expected-warning {{implicit conversion from 'const short' to 'char' changes value from 128 to -128}}
95 short new_short = max_short_plus_one; // expected-warning {{implicit conversion from 'const int' to 'short' changes value from 32768 to -32768}}
96 int new_int = max_int_plus_one; // expected-warning {{implicit conversion from 'const long' to 'int' changes value from 2147483648 to -2147483648}}
97
98 char hex_char = 0x80;
99 short hex_short = 0x8000;
100 int hex_int = 0x80000000;
101
102 char oct_char = 0200;
103 short oct_short = 0100000;
104 int oct_int = 020000000000;
105
106 char bin_char = 0b10000000;
107 short bin_short = 0b1000000000000000;
108 int bin_int = 0b10000000000000000000000000000000;
109
110 #define CHAR_MACRO_HEX 0xff
111 char macro_char_hex = CHAR_MACRO_HEX;
112 #define CHAR_MACRO_DEC 255
113 char macro_char_dec = CHAR_MACRO_DEC; // expected-warning {{implicit conversion from 'int' to 'char' changes value from 255 to -1}}
114
115 char array_init[] = { 255, 127, 128, 129, 0 };
116 }
117
118 #define A 1
119
test10()120 void test10() {
121 struct S {
122 unsigned a : 4;
123 } s;
124 s.a = -1;
125 s.a = 15;
126 s.a = -8;
127 s.a = ~0;
128 s.a = ~0U;
129 s.a = ~(1<<A);
130
131 s.a = -9; // expected-warning{{implicit truncation from 'int' to bit-field changes value from -9 to 7}}
132 s.a = 16; // expected-warning{{implicit truncation from 'int' to bit-field changes value from 16 to 0}}
133 }
134