diff --git a/vm/arrays.cpp b/vm/arrays.cpp
index 3060ac70a3..3945670e7d 100644
--- a/vm/arrays.cpp
+++ b/vm/arrays.cpp
@@ -7,9 +7,9 @@ namespace factor
 array *factor_vm::allot_array(cell capacity, cell fill_)
 {
 	data_root<object> fill(fill_,this);
-	data_root<array> new_array(allot_uninitialized_array<array>(capacity),this);
+	array *new_array = allot_uninitialized_array<array>(capacity);
 	memset_cell(new_array->data(),fill.value(),capacity * sizeof(cell));
-	return new_array.untagged();
+	return new_array;
 }
 
 /* push a new array on the stack */
diff --git a/vm/data_heap.cpp b/vm/data_heap.cpp
index a080417db0..c62b433af0 100755
--- a/vm/data_heap.cpp
+++ b/vm/data_heap.cpp
@@ -245,13 +245,11 @@ cell factor_vm::instances(cell type)
 	each_object(accum);
 	cell object_count = accum.objects.size();
 
-	data_roots.push_back((cell)&accum.objects[0]);
-	data_roots.push_back(object_count);
+	data_roots.push_back(data_root_range(&accum.objects[0],object_count));
 
 	array *objects = allot_array(object_count,false_object);
 	memcpy(objects->data(),&accum.objects[0],object_count * sizeof(cell));
 
-	data_roots.pop_back();
 	data_roots.pop_back();
 
 	return tag<array>(objects);
diff --git a/vm/data_roots.hpp b/vm/data_roots.hpp
index 1b3eb888ef..8e366a7cfd 100644
--- a/vm/data_roots.hpp
+++ b/vm/data_roots.hpp
@@ -7,8 +7,7 @@ struct data_root : public tagged<Type> {
 
 	void push()
 	{
-		parent->data_roots.push_back((cell)this);
-		parent->data_roots.push_back(1);
+		parent->data_roots.push_back(data_root_range(&this->value_,1));
 	}
 
 	explicit data_root(cell value_, factor_vm *parent_)
@@ -28,13 +27,6 @@ struct data_root : public tagged<Type> {
 
 	~data_root()
 	{
-#ifdef FACTOR_DEBUG
-		assert(parent->data_roots.back() == 1);
-#endif
-		parent->data_roots.pop_back();
-#ifdef FACTOR_DEBUG
-		assert(parent->data_roots.back() == (cell)this);
-#endif
 		parent->data_roots.pop_back();
 	}
 };
diff --git a/vm/gc.cpp b/vm/gc.cpp
index 98266ecc91..79fba81d19 100755
--- a/vm/gc.cpp
+++ b/vm/gc.cpp
@@ -218,18 +218,14 @@ void factor_vm::primitive_compact_gc()
 		true /* trace contexts? */);
 }
 
-void factor_vm::inline_gc(cell data_roots_base, cell data_roots_size)
+void factor_vm::inline_gc(cell *data_roots_base, cell data_roots_size)
 {
-	data_roots.push_back(data_roots_base);
-	data_roots.push_back(data_roots_size);
-
+	data_roots.push_back(data_root_range(data_roots_base,data_roots_size));
 	primitive_minor_gc();
-
-	data_roots.pop_back();
 	data_roots.pop_back();
 }
 
-VM_C_API void inline_gc(cell data_roots_base, cell data_roots_size, factor_vm *parent)
+VM_C_API void inline_gc(cell *data_roots_base, cell data_roots_size, factor_vm *parent)
 {
 	parent->inline_gc(data_roots_base,data_roots_size);
 }
diff --git a/vm/gc.hpp b/vm/gc.hpp
index 83e5da8aa1..a9250eddb2 100755
--- a/vm/gc.hpp
+++ b/vm/gc.hpp
@@ -53,6 +53,6 @@ struct gc_state {
 	void start_again(gc_op op_, factor_vm *parent);
 };
 
-VM_C_API void inline_gc(cell data_roots_base, cell data_roots_size, factor_vm *parent);
+VM_C_API void inline_gc(cell *data_roots_base, cell data_roots_size, factor_vm *parent);
 
 }
diff --git a/vm/layouts.hpp b/vm/layouts.hpp
index 5f3f3e9310..5eea72a002 100644
--- a/vm/layouts.hpp
+++ b/vm/layouts.hpp
@@ -373,4 +373,12 @@ struct tuple : public object {
 	cell *data() const { return (cell *)(this + 1); }
 };
 
+struct data_root_range {
+	cell *start;
+	cell len;
+
+	explicit data_root_range(cell *start_, cell len_) :
+		start(start_), len(len_) {}
+};
+
 }
diff --git a/vm/slot_visitor.hpp b/vm/slot_visitor.hpp
index eb24179336..af920fc6e2 100644
--- a/vm/slot_visitor.hpp
+++ b/vm/slot_visitor.hpp
@@ -43,15 +43,14 @@ template<typename Visitor> struct slot_visitor {
 
 	void visit_data_roots()
 	{
-		std::vector<cell>::const_iterator iter = parent->data_roots.begin();
-		std::vector<cell>::const_iterator end = parent->data_roots.end();
+		std::vector<data_root_range>::const_iterator iter = parent->data_roots.begin();
+		std::vector<data_root_range>::const_iterator end = parent->data_roots.end();
 
-		while(iter < end)
+		for(; iter < end; iter++)
 		{
-			cell start = *iter++;
-			cell len = *iter++;
-			for(cell index = 0; index < len; index++)
-				visit_handle((cell *)start + index);
+			data_root_range r = *iter;
+			for(cell index = 0; index < r.len; index++)
+				visit_handle(r.start + index);
 		}
 	}
 
diff --git a/vm/vm.hpp b/vm/vm.hpp
index cb0d0968a0..05f15af560 100755
--- a/vm/vm.hpp
+++ b/vm/vm.hpp
@@ -62,7 +62,7 @@ struct factor_vm
 	   allocates memory, it must wrap any references to the data and code
 	   heaps with data_root and code_root smart pointers, which register
 	   themselves here. See data_roots.hpp and code_roots.hpp */
-	std::vector<cell> data_roots;
+	std::vector<data_root_range> data_roots;
 	std::vector<cell> bignum_roots;
 	std::vector<code_root *> code_roots;
 
@@ -281,7 +281,7 @@ struct factor_vm
 	void primitive_minor_gc();
 	void primitive_full_gc();
 	void primitive_compact_gc();
-	void inline_gc(cell data_roots_base, cell data_roots_size);
+	void inline_gc(cell *data_roots_base, cell data_roots_size);
 	void primitive_enable_gc_events();
 	void primitive_disable_gc_events();
 	object *allot_object(header header, cell size);