Viewing file: constexpr-arith-overflow.C (7.12 KB) -rw-r--r-- Select action/file-type: (+) | (+) | (+) | Code (+) | Session (+) | (+) | SDB (+) | (+) | (+) | (+) | (+) | (+) |
// PR c++/70507 - integer overflow builtins not constant expressions // { dg-do compile { target c++11 } }
#define SCHAR_MAX __SCHAR_MAX__ #define SHRT_MAX __SHRT_MAX__ #define INT_MAX __INT_MAX__ #define LONG_MAX __LONG_MAX__ #define LLONG_MAX __LONG_LONG_MAX__ #define SCHAR_MIN (-__SCHAR_MAX__ - 1) #define SHRT_MIN (-__SHRT_MAX__ - 1) #define INT_MIN (-__INT_MAX__ - 1) #define LONG_MIN (-__LONG_MAX__ - 1) #define LLONG_MIN (-__LONG_LONG_MAX__ - 1) #define UCHAR_MAX (SCHAR_MAX * 2U + 1) #define USHRT_MAX (SHRT_MAX * 2U + 1) #define UINT_MAX (INT_MAX * 2U + 1) #define ULONG_MAX (LONG_MAX * 2LU + 1) #define ULLONG_MAX (LLONG_MAX * 2LLU + 1) #define USCHAR_MIN (-__USCHAR_MAX__ - 1) #define USHRT_MIN (-__USHRT_MAX__ - 1) #define UINT_MIN (-__UINT_MAX__ - 1) #define ULONG_MIN (-__ULONG_MAX__ - 1) #define ULLONG_MIN (-__ULONG_LONG_MAX__ - 1)
#define Assert(expr) static_assert ((expr), #expr)
#if __cplusplus >= 201402L template <class T> constexpr T add (T x, T y, T z = T ()) { return __builtin_add_overflow (x, y, &z) ? 0 : z; }
template <class T> constexpr T sub (T x, T y, T z = T ()) { return __builtin_sub_overflow (x, y, &z) ? 0 : z; }
template <class T> constexpr T mul (T x, T y, T z = T ()) { return __builtin_mul_overflow (x, y, &z) ? 0 : z; }
#define TEST_ADD(T, x, y, z) Assert (z == add<T>(x, y)) #define TEST_SUB(T, x, y, z) Assert (z == sub<T>(x, y)) #define TEST_MUL(T, x, y, z) Assert (z == mul<T>(x, y)) #else #define TEST_ADD(T, x, y, z) Assert (true) #define TEST_SUB(T, x, y, z) Assert (true) #define TEST_MUL(T, x, y, z) Assert (true) #endif
TEST_ADD (signed char, 0, 0, 0); TEST_ADD (signed char, 0, SCHAR_MAX, SCHAR_MAX); TEST_ADD (signed char, 1, SCHAR_MAX, 0); // overflow TEST_ADD (signed char, SCHAR_MAX, SCHAR_MAX, 0); // overflow TEST_ADD (signed char, 0, SCHAR_MIN, SCHAR_MIN); TEST_ADD (signed char, -1, SCHAR_MIN, 0); // overflow
TEST_ADD (short, 0, 0, 0); TEST_ADD (short, 0, SHRT_MAX, SHRT_MAX); TEST_ADD (short, 1, SHRT_MAX, 0); // overflow TEST_ADD (short, SHRT_MAX, SHRT_MAX, 0); // overflow TEST_ADD (short, 0, SHRT_MIN, SHRT_MIN); TEST_ADD (short, -1, SHRT_MIN, 0); // overflow TEST_ADD (short, SHRT_MIN, SHRT_MIN, 0); // overflow
TEST_ADD (int, 0, 0, 0); TEST_ADD (int, 0, INT_MAX, INT_MAX); TEST_ADD (int, 1, INT_MAX, 0); // overflow TEST_ADD (int, INT_MAX, INT_MAX, 0); // overflow TEST_ADD (int, 0, INT_MIN, INT_MIN); TEST_ADD (int, -1, INT_MIN, 0); // overflow TEST_ADD (int, INT_MIN, INT_MIN, 0); // overflow
TEST_ADD (long, 0, 0, 0); TEST_ADD (long, 0, LONG_MAX, LONG_MAX); TEST_ADD (long, 1, LONG_MAX, 0); // overflow TEST_ADD (long, LONG_MAX, LONG_MAX, 0); // overflow TEST_ADD (long, 0, LONG_MIN, LONG_MIN); TEST_ADD (long, -1, LONG_MIN, 0); // overflow TEST_ADD (long, LONG_MIN, LONG_MIN, 0); // overflow
TEST_ADD (long long, 0, 0, 0); TEST_ADD (long long, 0, LLONG_MAX, LLONG_MAX); TEST_ADD (long long, 1, LLONG_MAX, 0); // overflow TEST_ADD (long long, LLONG_MAX, LLONG_MAX, 0); // overflow TEST_ADD (long long, 0, LLONG_MIN, LLONG_MIN); TEST_ADD (long long, -1, LLONG_MIN, 0); // overflow TEST_ADD (long long, LLONG_MIN, LLONG_MIN, 0); // overflow
TEST_ADD (unsigned char, 0, 0, 0); TEST_ADD (unsigned char, 0, UCHAR_MAX, UCHAR_MAX); TEST_ADD (unsigned char, 1, UCHAR_MAX, 0); // overflow
TEST_ADD (unsigned char, UCHAR_MAX, UCHAR_MAX, 0); // overflow TEST_ADD (unsigned short, 0, 0, 0); TEST_ADD (unsigned short, 0, USHRT_MAX, USHRT_MAX); TEST_ADD (unsigned short, 1, USHRT_MAX, 0); // overflow TEST_ADD (unsigned short, USHRT_MAX, USHRT_MAX, 0); // overflow
TEST_ADD (unsigned, 0, 0, 0); TEST_ADD (unsigned, 0, UINT_MAX, UINT_MAX); TEST_ADD (unsigned, 1, UINT_MAX, 0); // overflow TEST_ADD (unsigned, UINT_MAX, UINT_MAX, 0); // overflow
TEST_ADD (unsigned long, 0, 0, 0); TEST_ADD (unsigned long, 0, ULONG_MAX, ULONG_MAX); TEST_ADD (unsigned long, 1, ULONG_MAX, 0); // overflow TEST_ADD (unsigned long, ULONG_MAX, ULONG_MAX, 0); // overflow
TEST_ADD (unsigned long long, 0, 0, 0); TEST_ADD (unsigned long long, 0, ULLONG_MAX, ULLONG_MAX); TEST_ADD (unsigned long long, 1, ULLONG_MAX, 0); // overflow TEST_ADD (unsigned long long, ULLONG_MAX, ULLONG_MAX, 0); // overflow
// Make sure the built-ins are accepted in the following contexts // where constant expressions are required and that they return // the expected overflow value.
namespace Enum {
enum Add { a0 = __builtin_add_overflow_p ( 1, 1, 0), a1 = __builtin_add_overflow_p (INT_MAX, 1, 0) };
Assert (a0 == 0); Assert (a1 == 1);
enum Sub { s0 = __builtin_sub_overflow_p ( 1, 1, 0), s1 = __builtin_sub_overflow_p (INT_MIN, 1, 0) };
Assert (s0 == 0); Assert (s1 == 1);
enum Mul { m0 = __builtin_add_overflow_p ( 1, 1, 0), m1 = __builtin_add_overflow_p (INT_MAX, INT_MAX, 0) };
Assert (m0 == 0); Assert (m1 == 1);
} // namespace Enum
namespace TemplateArg {
template <class T, class U, class V, T x, U y, bool v, bool z = __builtin_add_overflow_p (x, y, V ())> struct Add { Assert (z == v); };
template <class T, class U, class V, T x, U y, bool v, bool z = __builtin_sub_overflow_p (x, y, V ())> struct Sub { Assert (z == v); };
template <class T, class U, class V, T x, U y, bool v, bool z = __builtin_mul_overflow_p (x, y, V ())> struct Mul { Assert (z == v); };
template struct Add<int, int, int, 1, 1, false>; template struct Add<int, int, int, 1, INT_MAX, true>;
template struct Sub<int, int, int, 1, 1, false>; template struct Sub<int, int, int, -2, INT_MAX, true>;
template struct Mul<int, int, int, 1, 1, false>; template struct Mul<int, int, int, 2, INT_MAX / 2 + 1, true>;
} // namespace TemplateArg
#if __cplusplus >= 201402L
namespace Initializer {
struct Result { int res; bool vflow; };
constexpr Result add_vflow (int a, int b) { #if 1 Result res = { a + b, __builtin_add_overflow_p (a, b, int ()) }; #else // The following fails to compile because of c++/71391 - error // on aggregate initialization with side-effects in a constexpr // function int c = 0; Result res = { 0, __builtin_add_overflow (a, b, &c) }; res.c = c; #endif return res; }
constexpr Result sum = add_vflow (123, 456); Assert (sum.res == 123 + 456); Assert (!sum.vflow);
} // namespace Initializer
#endif // __cplusplus >= 201402L
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