diff --git a/lib/cretonne/meta/gen_instr.py b/lib/cretonne/meta/gen_instr.py
index c05cb51078..e6eaa82c32 100644
--- a/lib/cretonne/meta/gen_instr.py
+++ b/lib/cretonne/meta/gen_instr.py
@@ -111,6 +111,8 @@ def gen_instruction_data_impl(fmt):
     - `pub fn second_result_mut(&mut self) -> Option<&mut PackedOption<Value>>`
     - `pub fn arguments(&self, &pool) -> &[Value]`
     - `pub fn arguments_mut(&mut self, &pool) -> &mut [Value]`
+    - `pub fn take_value_list(&mut self) -> Option<ValueList>`
+    - `pub fn put_value_list(&mut self, args: ValueList>`
     """
 
     # The `opcode` and `first_type` methods simply read the `opcode` and `ty`
@@ -221,6 +223,45 @@ def gen_instruction_data_impl(fmt):
                 """)
         gen_arguments_method(fmt, True)
 
+        fmt.doc_comment(
+                """
+                Take out the value list with all the value arguments and return
+                it.
+
+                This leaves the value list in the instruction empty. Use
+                `put_value_list` to put the value list back.
+                """)
+        with fmt.indented(
+                'pub fn take_value_list(&mut self) -> Option<ValueList> {',
+                '}'):
+            with fmt.indented('match *self {', '}'):
+                for f in InstructionFormat.all_formats:
+                    n = 'InstructionData::' + f.name
+                    if f.has_value_list:
+                        fmt.line(
+                            n + ' { ref mut args, .. } => Some(args.take()),')
+                fmt.line('_ => None,')
+
+        fmt.doc_comment(
+                """
+                Put back a value list.
+
+                After removing a value list with `take_value_list()`, use this
+                method to put it back. It is required that this instruction has
+                a format that accepts a value list, and that the existing value
+                list is empty. This avoids leaking list pool memory.
+                """)
+        with fmt.indented(
+                'pub fn put_value_list(&mut self, vlist: ValueList) {', '}'):
+            with fmt.indented('let args = match *self {', '};'):
+                for f in InstructionFormat.all_formats:
+                    n = 'InstructionData::' + f.name
+                    if f.has_value_list:
+                        fmt.line(n + ' { ref mut args, .. } => args,')
+                fmt.line('_ => panic!("No value list: {:?}", self),')
+            fmt.line('assert!(args.is_empty(), "Value list already in use");')
+            fmt.line('*args = vlist;')
+
 
 def collect_instr_groups(isas):
     seen = set()
diff --git a/lib/cretonne/src/entity_list.rs b/lib/cretonne/src/entity_list.rs
index 2b8ebb783e..64a0a4c830 100644
--- a/lib/cretonne/src/entity_list.rs
+++ b/lib/cretonne/src/entity_list.rs
@@ -47,6 +47,7 @@
 //! reserved for the empty list which isn't allocated in the vector.
 
 use std::marker::PhantomData;
+use std::mem;
 
 use entity_map::EntityRef;
 
@@ -273,6 +274,13 @@ impl<T: EntityRef> EntityList<T> {
         self.index = 0;
     }
 
+    /// Take all elements from this list and return them as a new list. Leave this list empty.
+    ///
+    /// This is the equivalent of `Option::take()`.
+    pub fn take(&mut self) -> EntityList<T> {
+        mem::replace(self, Default::default())
+    }
+
     /// Appends an element to the back of the list.
     pub fn push(&mut self, element: T, pool: &mut ListPool<T>) {
         let idx = self.index as usize;