diff --git a/core/src/main/java/org/teavm/model/optimization/Devirtualization.java b/core/src/main/java/org/teavm/model/optimization/Devirtualization.java
index c67f3b5f7..6cf8ebebe 100644
--- a/core/src/main/java/org/teavm/model/optimization/Devirtualization.java
+++ b/core/src/main/java/org/teavm/model/optimization/Devirtualization.java
@@ -34,22 +34,38 @@ import org.teavm.model.instructions.InvocationType;
 import org.teavm.model.instructions.InvokeInstruction;
 
 public class Devirtualization {
+    static final boolean shouldLog = System.getProperty("org.teavm.logDevirtualization", "false").equals("true");
     private DependencyInfo dependency;
     private ClassHierarchy hierarchy;
     private Set<MethodReference> virtualMethods = new HashSet<>();
     private Set<? extends MethodReference> readonlyVirtualMethods = Collections.unmodifiableSet(virtualMethods);
+    private int virtualCallSites;
+    private int directCallSites;
 
     public Devirtualization(DependencyInfo dependency, ClassHierarchy hierarchy) {
         this.dependency = dependency;
         this.hierarchy = hierarchy;
     }
 
+    public int getVirtualCallSites() {
+        return virtualCallSites;
+    }
+
+    public int getDirectCallSites() {
+        return directCallSites;
+    }
+
     public void apply(MethodHolder method) {
         MethodDependencyInfo methodDep = dependency.getMethod(method.getReference());
         if (methodDep == null) {
             return;
         }
         Program program = method.getProgram();
+
+        if (shouldLog) {
+            System.out.println("DEVIRTUALIZATION running at " + method.getReference());
+        }
+
         for (int i = 0; i < program.basicBlockCount(); ++i) {
             BasicBlock block = program.basicBlockAt(i);
             for (Instruction insn : block) {
@@ -64,13 +80,46 @@ public class Devirtualization {
                 Set<MethodReference> implementations = getImplementations(var.getTypes(),
                         invoke.getMethod());
                 if (implementations.size() == 1) {
+                    MethodReference resolvedImplementaiton = implementations.iterator().next();
+                    if (shouldLog) {
+                        System.out.print("DIRECT CALL " + invoke.getMethod() + " resolved to "
+                                + resolvedImplementaiton.getClassName());
+                        if (insn.getLocation() != null) {
+                            System.out.print(" at " + insn.getLocation().getFileName() + ":"
+                                    + insn.getLocation().getLine());
+                        }
+                        System.out.println();
+                    }
                     invoke.setType(InvocationType.SPECIAL);
-                    invoke.setMethod(implementations.iterator().next());
+                    invoke.setMethod(resolvedImplementaiton);
+                    directCallSites++;
                 } else {
                     virtualMethods.addAll(implementations);
+                    if (shouldLog) {
+                        System.out.print("VIRTUAL CALL " + invoke.getMethod() + " resolved to [");
+                        boolean first = true;
+                        for (MethodReference impl : implementations) {
+                            if (!first) {
+                                System.out.print(", ");
+                            }
+                            first = false;
+                            System.out.print(impl.getClassName());
+                        }
+                        System.out.print("]");
+                        if (insn.getLocation() != null) {
+                            System.out.print(" at " + insn.getLocation().getFileName() + ":"
+                                    + insn.getLocation().getLine());
+                        }
+                        System.out.println();
+                    }
+                    virtualCallSites++;
                 }
             }
         }
+
+        if (shouldLog) {
+            System.out.println("DEVIRTUALIZATION complete for " + method.getReference());
+        }
     }
 
     private Set<MethodReference> getImplementations(String[] classNames, MethodReference ref) {
diff --git a/core/src/main/java/org/teavm/vm/TeaVM.java b/core/src/main/java/org/teavm/vm/TeaVM.java
index a4ddb7cda..fef5d87de 100644
--- a/core/src/main/java/org/teavm/vm/TeaVM.java
+++ b/core/src/main/java/org/teavm/vm/TeaVM.java
@@ -603,6 +603,12 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
         if (wasCancelled()) {
             return;
         }
+
+        boolean shouldLog = System.getProperty("org.teavm.logDevirtualization", "false").equals("true");
+        if (shouldLog) {
+            System.out.println("Running devirtualization");
+        }
+
         Devirtualization devirtualization = new Devirtualization(dependencyAnalyzer,
                 dependencyAnalyzer.getClassHierarchy());
         for (String className : classes.getClassNames()) {
@@ -618,6 +624,12 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
             }
         }
         virtualMethods = devirtualization.getVirtualMethods();
+
+        if (shouldLog) {
+            System.out.println("Devirtualization complete");
+            System.out.println("Virtual calls: " + devirtualization.getVirtualCallSites());
+            System.out.println("Direct calls: " + devirtualization.getDirectCallSites());
+        }
     }
 
     private void inline(ListableClassHolderSource classes) {