diff --git a/kernel/hashlib.h b/kernel/hashlib.h
index 9c53e6687..3136494c7 100644
--- a/kernel/hashlib.h
+++ b/kernel/hashlib.h
@@ -558,13 +558,16 @@ public:
 		int index;
 		const_iterator(const dict *ptr, int index) : ptr(ptr), index(index) { }
 	public:
-		typedef std::forward_iterator_tag iterator_category;
+		typedef std::bidirectional_iterator_tag iterator_category;
 		typedef std::pair<K, T> value_type;
 		typedef ptrdiff_t difference_type;
-		typedef std::pair<K, T>* pointer;
-		typedef std::pair<K, T>& reference;
+		typedef const std::pair<K, T>* pointer;
+		typedef const std::pair<K, T>& reference;
 		const_iterator() { }
 		const_iterator operator++() { index--; return *this; }
+		const_iterator operator++(int) { const_iterator tmp = *this; index--; return tmp; }
+		const_iterator operator--() { index++; return *this; }
+		const_iterator operator--(int) { const_iterator tmp = *this; index++; return tmp; }
 		const_iterator operator+=(int amt) { index -= amt; return *this; }
 		bool operator<(const const_iterator &other) const { return index > other.index; }
 		bool operator==(const const_iterator &other) const { return index == other.index; }
@@ -598,6 +601,13 @@ public:
 		const std::pair<K, T> *operator->() const { return &ptr->entries[index].udata; }
 		operator const_iterator() const { return const_iterator(ptr, index); }
 	};
+	using reverse_iterator = std::reverse_iterator<const_iterator>;
+	reverse_iterator rbegin() const {
+		return std::make_reverse_iterator(end());
+	}
+	reverse_iterator rend() const {
+		return std::make_reverse_iterator(begin());
+	}
 
 	constexpr dict()
 	{
@@ -847,7 +857,7 @@ public:
 
 	const_iterator begin() const { return const_iterator(this, int(entries.size())-1); }
 	const_iterator element(int n) const { return const_iterator(this, int(entries.size())-1-n); }
-	const_iterator end() const { return const_iterator(nullptr, -1); }
+	const_iterator end() const { return const_iterator(this, -1); }
 };
 
 template<typename K, typename OPS>
diff --git a/kernel/utils.h b/kernel/utils.h
index 6c9fe36a5..5c739aceb 100644
--- a/kernel/utils.h
+++ b/kernel/utils.h
@@ -21,6 +21,7 @@
 // do not depend on any other components of yosys (except stuff like log_*).
 
 #include "kernel/yosys.h"
+#include <iterator>
 
 #ifndef UTILS_H
 #define UTILS_H
@@ -276,6 +277,16 @@ inline int ceil_log2(int x)
 #endif
 }
 
+template <typename T>
+auto reversed(const T& container) {
+    struct reverse_view {
+        const T& cont;
+        auto begin() const { return cont.rbegin(); }
+        auto end() const { return cont.rend(); }
+    };
+    return reverse_view{container};
+}
+
 YOSYS_NAMESPACE_END
 
 #endif