diff --git a/lib/cretonne/src/context.rs b/lib/cretonne/src/context.rs
index ece812a5de..45914d8069 100644
--- a/lib/cretonne/src/context.rs
+++ b/lib/cretonne/src/context.rs
@@ -115,13 +115,6 @@ impl Context {
         self.domtree.compute(&self.func, &self.cfg);
     }
 
-    /// Ensure that a valid domtree exists.
-    pub fn ensure_domtree(&mut self) {
-        if !self.domtree.is_valid() {
-            self.domtree.compute(&self.func, &self.cfg);
-        }
-    }
-
     /// Perform simple GVN on the function.
     pub fn simple_gvn(&mut self) -> CtonResult {
         do_simple_gvn(&mut self.func, &mut self.cfg);
@@ -132,7 +125,6 @@ impl Context {
 
     /// Perform LICM on the function.
     pub fn licm(&mut self) -> CtonResult {
-        self.ensure_domtree();
         do_licm(
             &mut self.func,
             &mut self.cfg,
@@ -144,12 +136,11 @@ impl Context {
 
     /// Run the register allocator.
     pub fn regalloc(&mut self, isa: &TargetIsa) -> CtonResult {
-        self.ensure_domtree();
         self.regalloc.run(
             isa,
             &mut self.func,
             &self.cfg,
-            &self.domtree,
+            &mut self.domtree,
         )
     }
 
diff --git a/lib/cretonne/src/dominator_tree.rs b/lib/cretonne/src/dominator_tree.rs
index 2e9a6dc38d..18fd9e91b2 100644
--- a/lib/cretonne/src/dominator_tree.rs
+++ b/lib/cretonne/src/dominator_tree.rs
@@ -237,6 +237,14 @@ impl DominatorTree {
         !self.nodes.is_empty()
     }
 
+    /// Conveneince function to call `compute` if `compute` hasn't been called
+    /// since the last `clear()`.
+    pub fn ensure(&mut self, func: &Function, cfg: &ControlFlowGraph) {
+        if !self.is_valid() {
+            self.compute(func, cfg)
+        }
+    }
+
     /// Reset all internal data structures and compute a post-order for `cfg`.
     ///
     /// This leaves `rpo_number == 1` for all reachable EBBs, 0 for unreachable ones.
diff --git a/lib/cretonne/src/licm.rs b/lib/cretonne/src/licm.rs
index 20dfca9f5d..41aa498c5c 100644
--- a/lib/cretonne/src/licm.rs
+++ b/lib/cretonne/src/licm.rs
@@ -16,6 +16,7 @@ pub fn do_licm(
     domtree: &mut DominatorTree,
     loop_analysis: &mut LoopAnalysis,
 ) {
+    domtree.ensure(func, cfg);
     loop_analysis.compute(func, cfg, domtree);
     for lp in loop_analysis.loops() {
         // For each loop that we want to optimize we determine the set of loop-invariant
diff --git a/lib/cretonne/src/regalloc/context.rs b/lib/cretonne/src/regalloc/context.rs
index 2e11536596..92be408919 100644
--- a/lib/cretonne/src/regalloc/context.rs
+++ b/lib/cretonne/src/regalloc/context.rs
@@ -58,8 +58,11 @@ impl Context {
         isa: &TargetIsa,
         func: &mut Function,
         cfg: &ControlFlowGraph,
-        domtree: &DominatorTree,
+        domtree: &mut DominatorTree,
     ) -> CtonResult {
+        // Ensure that a valid domtree exists.
+        domtree.ensure(func, cfg);
+
         // `Liveness` and `Coloring` are self-clearing.
         self.virtregs.clear();