diff --git a/src/common/bit_util.h b/src/common/bit_util.h
index eae8748c..e7ec95b1 100644
--- a/src/common/bit_util.h
+++ b/src/common/bit_util.h
@@ -59,7 +59,7 @@ constexpr bool Bit(size_t bit_position, const T value) {
 #pragma warning(pop)
 #endif
 
-/// Sign-extends a value that has NBits bits to the full bitwidth of type T.
+/// Sign-extends a value that has bit_count bits to the full bitwidth of type T.
 template<size_t bit_count, typename T>
 inline T SignExtend(const T value) {
     static_assert(bit_count <= BitSize<T>(), "bit_count larger than bitsize of T");
@@ -72,6 +72,19 @@ inline T SignExtend(const T value) {
     return value;
 }
 
+/// Sign-extends a value that has bit_count bits to the full bitwidth of type T.
+template<typename T>
+inline T SignExtend(const size_t bit_count, const T value) {
+    ASSERT_MSG(bit_count <= BitSize<T>(), "bit_count larger than bitsize of T");
+
+    const T mask = static_cast<T>(1ULL << bit_count) - 1;
+    const bool signbit = Bit<T>(bit_count - 1, value);
+    if (signbit) {
+        return value | ~mask;
+    }
+    return value;
+}
+
 template <typename Integral>
 inline size_t BitCount(Integral value) {
     return std::bitset<BitSize<Integral>()>(value).count();