diff --git a/core/src/main/java/org/teavm/model/optimization/GlobalValueNumbering.java b/core/src/main/java/org/teavm/model/optimization/GlobalValueNumbering.java
index c048c8b79..27bd008e4 100644
--- a/core/src/main/java/org/teavm/model/optimization/GlobalValueNumbering.java
+++ b/core/src/main/java/org/teavm/model/optimization/GlobalValueNumbering.java
@@ -219,8 +219,7 @@ public class GlobalValueNumbering implements MethodOptimization {
             }
             namesCompatible = knownName.isEmpty() || name.isEmpty() || knownName.equals(name);
         }
-        if (known != null && domTree.dominates(known.location * 2 + 1, currentBlockIndex * 2) && known.value != var
-                && namesCompatible) {
+        if (known != null && dominates(known.location, currentBlockIndex) && known.value != var && namesCompatible) {
             map[var] = known.value;
             if (!noReplace) {
                 replaceMap[var] = known.value;
@@ -242,6 +241,10 @@ public class GlobalValueNumbering implements MethodOptimization {
         }
     }
 
+    private boolean dominates(int a, int b) {
+        return a == b || domTree.dominates(a * 2 + 1, b * 2);
+    }
+
     private InstructionVisitor constantPreprocessor = new AbstractInstructionVisitor() {
         private void setConstant(int index, Number value) {
             numericConstants[index] = value;