From 84affdb260889c24fd7348ed0cb0e463b8dbc244 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Tue, 17 Jul 2018 14:53:50 -0400
Subject: [PATCH] safe_ops: Avoid cases where shift bases are invalid with
signed values
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.
---
src/common/safe_ops.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/common/safe_ops.h b/src/common/safe_ops.h
index eb833ebb..6cc9ea4a 100644
--- a/src/common/safe_ops.h
+++ b/src/common/safe_ops.h
@@ -76,8 +76,8 @@ T ArithmeticShiftLeft(T value, int shift_amount) {
return ArithmeticShiftRight(value, -shift_amount);
}
- auto signed_value = static_cast<std::make_signed_t<T>>(value);
- return static_cast<T>(signed_value << shift_amount);
+ auto unsigned_value = static_cast<std::make_unsigned_t<T>>(value);
+ return static_cast<T>(unsigned_value << shift_amount);
}
template<typename T>