diff --git a/kernel/hashlib.h b/kernel/hashlib.h
index 24a1dbf6d..021cc66ee 100644
--- a/kernel/hashlib.h
+++ b/kernel/hashlib.h
@@ -31,6 +31,20 @@ inline unsigned int mkhash_add(unsigned int a, unsigned int b) {
 	return ((a << 5) + a) + b;
 }
 
+inline unsigned int mkhash_xorshift(unsigned int a) {
+	if (sizeof(a) == 4) {
+		a ^= a << 13;
+		a ^= a >> 17;
+		a ^= a << 5;
+	} else if (sizeof(a) == 8) {
+		a ^= a << 13;
+		a ^= a >> 7;
+		a ^= a << 17;
+	} else
+		throw std::runtime_error("mkhash_xorshift() only implemented for 32 bit and 64 bit ints");
+	return a;
+}
+
 template<typename T> struct hash_ops {
 	bool cmp(const T &a, const T &b) const {
 		return a == b;
@@ -122,7 +136,11 @@ inline int hashtable_size(int old_size)
 	if (old_size <  250999999) return  250999999;
 	if (old_size <  503000009) return  503000009;
 	if (old_size < 1129999999) return 1129999999;
-	throw std::length_error("hash table exceeded maximum size");
+
+	if (sizeof(old_size) == 4)
+		throw std::length_error("hash table exceeded maximum size. recompile with -mint64.");
+
+	return old_size * 2;
 }
 
 template<typename K, typename T, typename OPS = hash_ops<K>>
diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index cdbaa5bbf..f25df175d 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -236,8 +236,9 @@ void RTLIL::Selection::optimize(RTLIL::Design *design)
 
 RTLIL::Design::Design()
 {
-	static unsigned int hashidx_count = 0;
-	hashidx_ = hashidx_count++;
+	static unsigned int hashidx_count = 123456789;
+	hashidx_count = mkhash_xorshift(hashidx_count);
+	hashidx_ = hashidx_count;
 
 	refcount_modules_ = 0;
 	selection_stack.push_back(RTLIL::Selection());
@@ -450,8 +451,9 @@ std::vector<RTLIL::Module*> RTLIL::Design::selected_whole_modules_warn() const
 
 RTLIL::Module::Module()
 {
-	static unsigned int hashidx_count = 0;
-	hashidx_ = hashidx_count++;
+	static unsigned int hashidx_count = 123456789;
+	hashidx_count = mkhash_xorshift(hashidx_count);
+	hashidx_ = hashidx_count;
 
 	design = nullptr;
 	refcount_wires_ = 0;
@@ -1741,8 +1743,9 @@ RTLIL::Cell* RTLIL::Module::addDlatchsrGate(RTLIL::IdString name, RTLIL::SigSpec
 
 RTLIL::Wire::Wire()
 {
-	static unsigned int hashidx_count = 0;
-	hashidx_ = hashidx_count++;
+	static unsigned int hashidx_count = 123456789;
+	hashidx_count = mkhash_xorshift(hashidx_count);
+	hashidx_ = hashidx_count;
 
 	module = nullptr;
 	width = 1;
@@ -1755,8 +1758,9 @@ RTLIL::Wire::Wire()
 
 RTLIL::Memory::Memory()
 {
-	static unsigned int hashidx_count = 0;
-	hashidx_ = hashidx_count++;
+	static unsigned int hashidx_count = 123456789;
+	hashidx_count = mkhash_xorshift(hashidx_count);
+	hashidx_ = hashidx_count;
 
 	width = 1;
 	size = 0;
@@ -1764,8 +1768,9 @@ RTLIL::Memory::Memory()
 
 RTLIL::Cell::Cell() : module(nullptr)
 {
-	static unsigned int hashidx_count = 0;
-	hashidx_ = hashidx_count++;
+	static unsigned int hashidx_count = 123456789;
+	hashidx_count = mkhash_xorshift(hashidx_count);
+	hashidx_ = hashidx_count;
 
 	// log("#memtrace# %p\n", this);
 	memhasher();
diff --git a/kernel/rtlil.h b/kernel/rtlil.h
index f759a014f..5bca060f4 100644
--- a/kernel/rtlil.h
+++ b/kernel/rtlil.h
@@ -712,8 +712,9 @@ struct RTLIL::Monitor
 	unsigned int hash() const { return hashidx_; }
 
 	Monitor() {
-		static unsigned int hashidx_count = 0;
-		hashidx_ = hashidx_count++;
+		static unsigned int hashidx_count = 123456789;
+		hashidx_count = mkhash_xorshift(hashidx_count);
+		hashidx_ = hashidx_count;
 	}
 
 	virtual ~Monitor() { }
diff --git a/kernel/yosys.h b/kernel/yosys.h
index bbcbd5fed..8ddd6f540 100644
--- a/kernel/yosys.h
+++ b/kernel/yosys.h
@@ -136,6 +136,7 @@ using std::vector;
 using std::string;
 using hashlib::mkhash;
 using hashlib::mkhash_add;
+using hashlib::mkhash_xorshift;
 using hashlib::hash_ops;
 using hashlib::hash_cstr_ops;
 using hashlib::hash_ptr_ops;