// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++20 -verify=expected,all %s
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++17 -verify=cxx17,all %s
// RUN: %clang_cc1 -std=c++20 -verify=ref,all %s
// RUN: %clang_cc1 -std=c++17 -verify=ref-cxx17,all %s
#define INT_MIN (~__INT_MAX__)
namespace shifts {
constexpr void test() { // ref-error {{constexpr function never produces a constant expression}} \
// ref-cxx17-error {{constexpr function never produces a constant expression}} \
// expected-error {{constexpr function never produces a constant expression}} \
// cxx17-error {{constexpr function never produces a constant expression}} \
char c; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
c = 0 << 0;
c = 0 << 1;
c = 1 << 0;
c = 1 << -0;
c = 1 >> -0;
c = 1 << -1; // expected-warning {{shift count is negative}} \
// expected-note {{negative shift count -1}} \
// cxx17-note {{negative shift count -1}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-note {{negative shift count -1}} \
// ref-cxx17-warning {{shift count is negative}} \
// ref-cxx17-note {{negative shift count -1}}
c = 1 >> -1; // expected-warning {{shift count is negative}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-cxx17-warning {{shift count is negative}}
c = 1 << (unsigned)-1; // expected-warning {{shift count >= width of type}} \
// expected-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}} \
// cxx17-warning {{shift count >= width of type}} \
// cxx17-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}} \
// ref-warning {{shift count >= width of type}} \
// ref-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}} \
// ref-cxx17-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}}
c = 1 >> (unsigned)-1; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c = 1 << c;
c <<= 0;
c >>= 0;
c <<= 1;
c >>= 1;
c <<= -1; // expected-warning {{shift count is negative}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-cxx17-warning {{shift count is negative}}
c >>= -1; // expected-warning {{shift count is negative}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-cxx17-warning {{shift count is negative}}
c <<= 999999; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c >>= 999999; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c <<= __CHAR_BIT__; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c >>= __CHAR_BIT__; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c <<= __CHAR_BIT__+1; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c >>= __CHAR_BIT__+1; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
(void)((long)c << __CHAR_BIT__);
int i; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
i = 1 << (__INT_WIDTH__ - 2);
i = 2 << (__INT_WIDTH__ - 1); // cxx17-warning {{bits to represent, but 'int' only has}} \
// ref-cxx17-warning {{bits to represent, but 'int' only has}}
i = 1 << (__INT_WIDTH__ - 1); // cxx17-warning-not {{sets the sign bit of the shift expression}}
i = -1 << (__INT_WIDTH__ - 1); // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}}
i = -1 << 0; // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}}
i = 0 << (__INT_WIDTH__ - 1);
i = (char)1 << (__INT_WIDTH__ - 2);
unsigned u; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
u = 1U << (__INT_WIDTH__ - 1);
u = 5U << (__INT_WIDTH__ - 1);
long long int lli; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
lli = INT_MIN << 2; // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}}
lli = 1LL << (sizeof(long long) * __CHAR_BIT__ - 2);
}
static_assert(1 << 4 == 16, "");
constexpr unsigned m = 2 >> 1;
static_assert(m == 1, "");
constexpr unsigned char c = 0 << 8;
static_assert(c == 0, "");
static_assert(true << 1, "");
static_assert(1 << (__INT_WIDTH__ +1) == 0, ""); // expected-error {{not an integral constant expression}} \
// expected-note {{>= width of type 'int'}} \
// cxx17-error {{not an integral constant expression}} \
// cxx17-note {{>= width of type 'int'}} \
// ref-error {{not an integral constant expression}} \
// ref-note {{>= width of type 'int'}} \
// ref-cxx17-error {{not an integral constant expression}} \
// ref-cxx17-note {{>= width of type 'int'}}
constexpr int i1 = 1 << -1; // expected-error {{must be initialized by a constant expression}} \
// expected-note {{negative shift count -1}} \
// cxx17-error {{must be initialized by a constant expression}} \
// cxx17-note {{negative shift count -1}} \
// ref-error {{must be initialized by a constant expression}} \
// ref-note {{negative shift count -1}} \
// ref-cxx17-error {{must be initialized by a constant expression}} \
// ref-cxx17-note {{negative shift count -1}}
constexpr int i2 = 1 << (__INT_WIDTH__ + 1); // expected-error {{must be initialized by a constant expression}} \
// expected-note {{>= width of type}} \
// cxx17-error {{must be initialized by a constant expression}} \
// cxx17-note {{>= width of type}} \
// ref-error {{must be initialized by a constant expression}} \
// ref-note {{>= width of type}} \
// ref-cxx17-error {{must be initialized by a constant expression}} \
// ref-cxx17-note {{>= width of type}}
constexpr char c2 = 1;
constexpr int i3 = c2 << (__CHAR_BIT__ + 1); // Not ill-formed
/// The purpose of these few lines is to test that we can shift more bits
/// than an unsigned *of the host* has. There was a bug where we casted
/// to host-unsigned. However, we cannot query what a host-unsigned even is
/// here, so only test this on platforms where `sizeof(long long) > sizeof(unsigned)`.
constexpr long long int L = 1;
constexpr signed int R = (sizeof(unsigned) * 8) + 1;
constexpr decltype(L) M = (R > 32 && R < 64) ? L << R : 0;
constexpr decltype(L) M2 = (R > 32 && R < 64) ? L >> R : 0;
constexpr int signedShift() { // cxx17-error {{never produces a constant expression}} \
// ref-cxx17-error {{never produces a constant expression}}
return 1024 << 31; // cxx17-warning {{signed shift result}} \
// ref-cxx17-warning {{signed shift result}} \
// cxx17-note {{signed left shift discards bits}} \
// ref-cxx17-note {{signed left shift discards bits}}
}
constexpr int negativeShift() { // cxx17-error {{never produces a constant expression}} \
// ref-cxx17-error {{never produces a constant expression}}
return -1 << 2; // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}} \
// cxx17-note {{left shift of negative value -1}} \
// ref-cxx17-note {{left shift of negative value -1}}
}
constexpr int foo(int a) {
return -a << 2; // cxx17-note {{left shift of negative value -10}} \
// ref-cxx17-note {{left shift of negative value -10}} \
// cxx17-note {{left shift of negative value -2}} \
// ref-cxx17-note {{left shift of negative value -2}}
}
static_assert(foo(10)); // cxx17-error {{not an integral constant expression}} \
// cxx17-note {{in call to 'foo(10)'}} \
// ref-cxx17-error {{not an integral constant expression}} \
// ref-cxx17-note {{in call to 'foo(10)'}}
constexpr int a = -2;
static_assert(foo(a));
static_assert(foo(-a)); // cxx17-error {{not an integral constant expression}} \
// cxx17-note {{in call to 'foo(2)'}} \
// ref-cxx17-error {{not an integral constant expression}} \
// ref-cxx17-note {{in call to 'foo(2)'}}
};
namespace LongInt {
constexpr int f() {
int a = 1;
a <<= (long)0;
return 1;
}
static_assert(f() == 1, "");
};
enum shiftof {
X = (1<<-29), // all-error {{expression is not an integral constant expression}} \
// all-note {{negative shift count -29}}
X2 = (-1<<29), // cxx17-error {{expression is not an integral constant expression}} \
// cxx17-note {{left shift of negative value -1}} \
// ref-cxx17-error {{expression is not an integral constant expression}} \
// ref-cxx17-note {{left shift of negative value -1}}
X3 = (1<<32) // all-error {{expression is not an integral constant expression}} \
// all-note {{shift count 32 >= width of type 'int'}}
};
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