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safe_ops: Avoid cases where shift bases are invalid with signed values

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For example, say the converted signed type is s64, shifting left  by 63
bits would be undefined behavior.

However, given an ASL is essentially the same behavior as an LSL
we can just use an unsigned type instead of converting to a signed type.
This commit is contained in:
Lioncash 2018-07-17 14:53:50 -04:00 committed by MerryMage
parent d0274f412a
commit 84affdb260
1 changed files with 2 additions and 2 deletions
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4
src/common/safe_ops.h
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@ -76,8 +76,8 @@ T ArithmeticShiftLeft(T value, int shift_amount) {
return ArithmeticShiftRight(value, -shift_amount); return ArithmeticShiftRight(value, -shift_amount);
} }
auto signed_value = static_cast<std::make_signed_t<T>>(value); auto unsigned_value = static_cast<std::make_unsigned_t<T>>(value);
return static_cast<T>(signed_value << shift_amount); return static_cast<T>(unsigned_value << shift_amount);
} }
template<typename T> template<typename T>