diff --git a/core/src/main/java/org/teavm/common/DJGraph.java b/core/src/main/java/org/teavm/common/DJGraph.java
index 152893c72..7cdbbff5e 100644
--- a/core/src/main/java/org/teavm/common/DJGraph.java
+++ b/core/src/main/java/org/teavm/common/DJGraph.java
@@ -114,10 +114,6 @@ public class DJGraph {
         }
     }
 
-    public DominatorTree getDomTree() {
-        return domTree;
-    }
-
     public MutableDirectedGraph getCfg() {
         return cfg;
     }
@@ -136,7 +132,17 @@ public class DJGraph {
     }
 
     public boolean isDomEdge(int i, int j) {
-        return domTree.immediateDominatorOf(mergeRoot[j]) == mergeRoot[i];
+        return immediateDominatorOf(j) == mergeRoot[i];
+    }
+
+    public int immediateDominatorOf(int node) {
+        int dom = domTree.immediateDominatorOf(mergeRoot[node]);
+        return dom >= 0 ? mergeRoot[dom] : dom;
+    }
+
+    public int commonDominatorOf(int a, int b) {
+        int dom = domTree.commonDominatorOf(mergeRoot[a], mergeRoot[b]);
+        return dom >= 0 ? mergeRoot[dom] : dom;
     }
 
     public boolean isJoinEdge(int i, int j) {
diff --git a/core/src/main/java/org/teavm/common/IrreducibleGraphConverter.java b/core/src/main/java/org/teavm/common/IrreducibleGraphConverter.java
index 7569e4006..b1eb1ad4f 100644
--- a/core/src/main/java/org/teavm/common/IrreducibleGraphConverter.java
+++ b/core/src/main/java/org/teavm/common/IrreducibleGraphConverter.java
@@ -84,7 +84,7 @@ class IrreducibleGraphConverter {
         // Find shared dominator
         int sharedDom = scc[0];
         for (int i = 1; i < scc.length; ++i) {
-            sharedDom = djGraph.getDomTree().commonDominatorOf(sharedDom, scc[i]);
+            sharedDom = djGraph.commonDominatorOf(sharedDom, scc[i]);
         }
 
         for (int i = 0; i < scc.length; ++i) {
@@ -103,7 +103,7 @@ class IrreducibleGraphConverter {
         }
         for (int i = 0; i < scc.length; ++i) {
             int node = scc[i];
-            int idom = djGraph.getDomTree().immediateDominatorOf(node);
+            int idom = djGraph.immediateDominatorOf(node);
             if (idom != sharedDom) {
                 partitions.union(i, sccBack[idom]);
             }
diff --git a/core/src/test/java/org/teavm/common/GraphTest.java b/core/src/test/java/org/teavm/common/GraphTest.java
index 09300c0e5..fa40f1a81 100644
--- a/core/src/test/java/org/teavm/common/GraphTest.java
+++ b/core/src/test/java/org/teavm/common/GraphTest.java
@@ -24,7 +24,6 @@ import com.carrotsearch.hppc.IntSet;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.function.IntPredicate;
-import org.junit.Ignore;
 import org.junit.Test;
 
 public class GraphTest {
@@ -172,12 +171,10 @@ public class GraphTest {
 
         assertTrue("Should be irreducible", GraphUtils.isIrreducible(graph));
         assertFalse("Should be reducible", GraphUtils.isIrreducible(result));
-        assertTrue("Should be equialent", isEquialent(backend, graph));
+        assertTrue("Should be equivalent", isEquialent(backend, graph));
     }
 
-    // TODO: fix and unignore
     @Test
-    @Ignore
     public void irreducibleGraphSplit3() {
         GraphBuilder builder = new GraphBuilder();
         builder.addEdge(0, 1);
@@ -232,8 +229,8 @@ public class GraphTest {
     private IntPredicate filter = (int node) -> true;
 
     private void sortSccs(int[][] sccs) {
-        for (int i = 0; i < sccs.length; ++i) {
-            Arrays.sort(sccs[i]);
+        for (int[] scc : sccs) {
+            Arrays.sort(scc);
         }
         Arrays.sort(sccs, Comparator.comparingInt(o -> o[0]));
     }