146 lines · c
1// RUN: %clang_cc1 -fsyntax-only -ffreestanding -verify=expected,one-bit -triple x86_64-apple-darwin %s2// RUN: %clang_cc1 -fsyntax-only -ffreestanding -Wno-single-bit-bitfield-constant-conversion -verify -triple x86_64-apple-darwin %s3 4#include <stdbool.h>5 6// This file tests -Wconstant-conversion, a subcategory of -Wconversion7// which is on by default.8 9void test_6792488(void) {10 int x = 0x3ff0000000000000U; // expected-warning {{implicit conversion from 'unsigned long' to 'int' changes value from 4607182418800017408 to 0}}11}12 13void test_7809123(void) {14 struct { int i5 : 5; } a;15 16 a.i5 = 36; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 36 to 4}}17}18 19void test(void) {20 struct S {21 int b : 1; // The only valid values are 0 and -1.22 } s;23 24 s.b = -3; // expected-warning {{implicit truncation from 'int' to bit-field changes value from -3 to -1}}25 s.b = -2; // expected-warning {{implicit truncation from 'int' to bit-field changes value from -2 to 0}}26 s.b = -1; // no-warning27 s.b = 0; // no-warning28 s.b = 1; // one-bit-warning {{implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1}}29 s.b = true; // no-warning (we suppress it manually to reduce false positives)30 s.b = false; // no-warning31 s.b = 2; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 2 to 0}}32}33 34enum Test2 { K_zero, K_one };35enum Test2 test2(enum Test2 *t) {36 *t = 20;37 return 10; // shouldn't warn38}39 40void test3(void) {41 struct A {42 unsigned int foo : 2;43 int bar : 2;44 };45 46 struct A a = { 0, 10 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to -2}}47 struct A b[] = { 0, 10, 0, 0 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to -2}}48 struct A c[] = {{10, 0}}; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to 2}}49 struct A d = (struct A) { 10, 0 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to 2}}50 struct A e = { .foo = 10 }; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 10 to 2}}51}52 53void test4(void) {54 struct A {55 char c : 2;56 } a;57 58 a.c = 0x101; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 257 to 1}}59}60 61void test5(void) {62 struct A {63 _Bool b : 1;64 } a;65 66 // Don't warn about this implicit conversion to bool, or at least67 // don't warn about it just because it's a bit-field.68 a.b = 100;69}70 71void test6(void) {72 // Test that unreachable code doesn't trigger the truncation warning.73 unsigned char x = 0 ? 65535 : 1; // no-warning74 unsigned char y = 1 ? 65535 : 1; // expected-warning {{changes value}}75}76 77void test7(void) {78 struct {79 unsigned int twoBits1:2;80 unsigned int twoBits2:2;81 unsigned int reserved:28;82 } f;83 84 f.twoBits1 = ~0; // no-warning85 f.twoBits1 = ~1; // no-warning86 f.twoBits2 = ~2; // expected-warning {{implicit truncation from 'int' to bit-field changes value from -3 to 1}}87 f.twoBits1 &= ~1; // no-warning88 f.twoBits2 &= ~2; // no-warning89}90 91void test8(void) {92 enum E { A, B, C };93 struct { enum E x : 1; } f;94 f.x = C; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 2 to 0}}95}96 97void test9(void) {98 const char max_char = 0x7F;99 const short max_short = 0x7FFF;100 const int max_int = 0x7FFFFFFF;101 102 const short max_char_plus_one = (short)max_char + 1;103 const int max_short_plus_one = (int)max_short + 1;104 const long max_int_plus_one = (long)max_int + 1;105 106 char new_char = max_char_plus_one; // expected-warning {{implicit conversion from 'const short' to 'char' changes value from 128 to -128}}107 short new_short = max_short_plus_one; // expected-warning {{implicit conversion from 'const int' to 'short' changes value from 32768 to -32768}}108 int new_int = max_int_plus_one; // expected-warning {{implicit conversion from 'const long' to 'int' changes value from 2147483648 to -2147483648}}109 110 char hex_char = 0x80;111 short hex_short = 0x8000;112 int hex_int = 0x80000000;113 114 char oct_char = 0200;115 short oct_short = 0100000;116 int oct_int = 020000000000;117 118 char bin_char = 0b10000000;119 short bin_short = 0b1000000000000000;120 int bin_int = 0b10000000000000000000000000000000;121 122#define CHAR_MACRO_HEX 0xff123 char macro_char_hex = CHAR_MACRO_HEX;124#define CHAR_MACRO_DEC 255125 char macro_char_dec = CHAR_MACRO_DEC; // expected-warning {{implicit conversion from 'int' to 'char' changes value from 255 to -1}}126 127 char array_init[] = { 255, 127, 128, 129, 0 };128}129 130#define A 1131 132void test10(void) {133 struct S {134 unsigned a : 4;135 } s;136 s.a = -1;137 s.a = 15;138 s.a = -8;139 s.a = ~0;140 s.a = ~0U;141 s.a = ~(1<<A);142 143 s.a = -9; // expected-warning{{implicit truncation from 'int' to bit-field changes value from -9 to 7}}144 s.a = 16; // expected-warning{{implicit truncation from 'int' to bit-field changes value from 16 to 0}}145}146