1 // RUN: %clang_cc1 -Wall -Wno-unused-but-set-variable -Wshift-sign-overflow -ffreestanding -fsyntax-only -verify=expected,cxx17 -std=c++17 %s 2 // RUN: %clang_cc1 -Wall -Wno-unused-but-set-variable -Wshift-sign-overflow -ffreestanding -fsyntax-only -verify=expected,cxx2a -std=c++2a %s 3 4 #include <limits.h> 5 6 #define WORD_BIT (sizeof(int) * CHAR_BIT) 7 8 enum { 9 X = 1 << 0, 10 Y = 1 << 1, 11 Z = 1 << 2 12 }; 13 14 void test() { 15 char c; 16 17 c = 0 << 0; 18 c = 0 << 1; 19 c = 1 << 0; 20 c = 1 << -0; 21 c = 1 >> -0; 22 c = 1 << -1; // expected-warning {{shift count is negative}} 23 c = 1 >> -1; // expected-warning {{shift count is negative}} 24 c = 1 << (unsigned)-1; // expected-warning {{shift count >= width of type}} 25 // expected-warning@-1 {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}} 26 c = 1 >> (unsigned)-1; // expected-warning {{shift count >= width of type}} 27 c = 1 << c; 28 c <<= 0; 29 c >>= 0; 30 c <<= 1; 31 c >>= 1; 32 c <<= -1; // expected-warning {{shift count is negative}} 33 c >>= -1; // expected-warning {{shift count is negative}} 34 c <<= 999999; // expected-warning {{shift count >= width of type}} 35 c >>= 999999; // expected-warning {{shift count >= width of type}} 36 c <<= CHAR_BIT; // expected-warning {{shift count >= width of type}} 37 c >>= CHAR_BIT; // expected-warning {{shift count >= width of type}} 38 c <<= CHAR_BIT+1; // expected-warning {{shift count >= width of type}} 39 c >>= CHAR_BIT+1; // expected-warning {{shift count >= width of type}} 40 (void)((long)c << CHAR_BIT); 41 42 int i; 43 i = 1 << (WORD_BIT - 2); 44 i = 2 << (WORD_BIT - 1); // cxx17-warning {{bits to represent, but 'int' only has}} 45 i = 1 << (WORD_BIT - 1); // cxx17-warning {{sets the sign bit of the shift expression}} 46 i = -1 << (WORD_BIT - 1); // cxx17-warning {{shifting a negative signed value is undefined}} 47 i = -1 << 0; // cxx17-warning {{shifting a negative signed value is undefined}} 48 i = 0 << (WORD_BIT - 1); 49 i = (char)1 << (WORD_BIT - 2); 50 51 unsigned u; 52 u = 1U << (WORD_BIT - 1); 53 u = 5U << (WORD_BIT - 1); 54 55 long long int lli; 56 lli = INT_MIN << 2; // cxx17-warning {{shifting a negative signed value is undefined}} 57 lli = 1LL << (sizeof(long long) * CHAR_BIT - 2); 58 } 59 60 #define a 0 61 #define ashift 8 62 enum { b = (a << ashift) }; 63 64 // Don't warn for negative shifts in code that is unreachable. 65 void test_pr5544() { 66 (void) (((1) > 63 && (1) < 128 ? (((unsigned long long) 1)<<((1)-64)) : (unsigned long long) 0)); // no-warning 67 } 68 69 void test_shift_too_much(char x) { 70 if (0) 71 (void) (x >> 80); // no-warning 72 (void) (x >> 80); // expected-warning {{shift count >= width of type}} 73 } 74 75 typedef unsigned vec16 __attribute__((vector_size(16))); 76 typedef unsigned vec8 __attribute__((vector_size(8))); 77 78 void vect_shift_1(vec16 *x) { *x = *x << 4; } 79 80 void vect_shift_2(vec16 *x, vec16 y) { *x = *x << y; } 81 82 void vect_shift_3(vec16 *x, vec8 y) { 83 *x = *x << y; // expected-error {{vector operands do not have the same number of elements}} 84 } 85