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 bitfield 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 bitfield changes value from 10 to -2}}
35 struct A b[] = { 0, 10, 0, 0 }; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to -2}}
36 struct A c[] = {{10, 0}}; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to 2}}
37 struct A d = (struct A) { 10, 0 }; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 10 to 2}}
38 struct A e = { .foo = 10 }; // expected-warning {{implicit truncation from 'int' to bitfield 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 bitfield 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 bitfield.
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 = ~1; // expected-warning {{implicit truncation from 'int' to bitfield changes value from -2 to 2}}
73 f.twoBits2 = ~2; // expected-warning {{implicit truncation from 'int' to bitfield changes value from -3 to 1}}
74 f.twoBits1 &= ~1; // no-warning
75 f.twoBits2 &= ~2; // no-warning
76 }
77
test8()78 void test8() {
79 enum E { A, B, C };
80 struct { enum E x : 1; } f;
81 f.x = C; // expected-warning {{implicit truncation from 'int' to bitfield changes value from 2 to 0}}
82 }
83