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Diffstat (limited to 'src/common/overflow.h')
-rw-r--r-- | src/common/overflow.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/src/common/overflow.h b/src/common/overflow.h index 44d8e7e73..e184ead95 100644 --- a/src/common/overflow.h +++ b/src/common/overflow.h @@ -3,6 +3,7 @@ #pragma once +#include <algorithm> #include <type_traits> #include "bit_cast.h" @@ -19,4 +20,21 @@ inline T WrappingAdd(T lhs, T rhs) { return BitCast<T>(lhs_u + rhs_u); } +template <typename T> + requires(std::is_integral_v<T> && std::is_signed_v<T>) +inline bool CanAddWithoutOverflow(T lhs, T rhs) { +#ifdef _MSC_VER + if (lhs >= 0 && rhs >= 0) { + return WrappingAdd(lhs, rhs) >= std::max(lhs, rhs); + } else if (lhs < 0 && rhs < 0) { + return WrappingAdd(lhs, rhs) <= std::min(lhs, rhs); + } else { + return true; + } +#else + T res; + return !__builtin_add_overflow(lhs, rhs, &res); +#endif +} + } // namespace Common |