diff --git a/src/main/java/com/android/tools/r8/graph/DexItemFactory.java b/src/main/java/com/android/tools/r8/graph/DexItemFactory.java
index 1dc0e89..2591960 100644
--- a/src/main/java/com/android/tools/r8/graph/DexItemFactory.java
+++ b/src/main/java/com/android/tools/r8/graph/DexItemFactory.java
@@ -680,14 +680,18 @@
   // Library methods listed here are based on their original implementations. That is, we assume
   // these cannot be overridden.
   public final Set<DexMethod> libraryMethodsReturningNonNull =
-      ImmutableSet.of(
-          classMethods.getName,
-          classMethods.getSimpleName,
-          classMethods.forName,
-          objectsMethods.requireNonNull,
-          objectsMethods.requireNonNullWithMessage,
-          objectsMethods.requireNonNullWithMessageSupplier,
-          stringMembers.valueOf);
+      ImmutableSet.<DexMethod>builder()
+          .add(
+              classMethods.getName,
+              classMethods.getSimpleName,
+              classMethods.forName,
+              objectsMethods.requireNonNull,
+              objectsMethods.requireNonNullWithMessage,
+              objectsMethods.requireNonNullWithMessageSupplier,
+              stringMembers.valueOf)
+          .addAll(stringBufferMethods.appendMethods)
+          .addAll(stringBuilderMethods.appendMethods)
+          .build();
 
   // TODO(b/119596718): More idempotent methods? Any singleton accessors? E.g.,
   // java.util.Calendar#getInstance(...) // 4 variants
diff --git a/src/main/java/com/android/tools/r8/graph/DexMethod.java b/src/main/java/com/android/tools/r8/graph/DexMethod.java
index e00c1fe..d35b1a0 100644
--- a/src/main/java/com/android/tools/r8/graph/DexMethod.java
+++ b/src/main/java/com/android/tools/r8/graph/DexMethod.java
@@ -261,6 +261,10 @@
     return factory.isConstructor(this);
   }
 
+  public boolean mustBeInlinedIntoInstanceInitializer(DexItemFactory dexItemFactory) {
+    return getName().startsWith(dexItemFactory.temporaryConstructorMethodPrefix);
+  }
+
   public DexMethod withExtraArgumentPrepended(DexType type, DexItemFactory dexItemFactory) {
     return dexItemFactory.createMethod(
         holder, dexItemFactory.prependTypeToProto(type, proto), name);
diff --git a/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java b/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java
index 495be54..dd0486a 100644
--- a/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java
+++ b/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java
@@ -155,7 +155,7 @@
         new AllInstantiatedOrUninstantiated(appView),
         new SameParentClass(),
         new SameNestHost(),
-        new PreserveMethodCharacteristics(),
+        new PreserveMethodCharacteristics(appView),
         new SameFeatureSplit(appView),
         new RespectPackageBoundaries(appView),
         new DontMergeSynchronizedClasses(appView),
diff --git a/src/main/java/com/android/tools/r8/horizontalclassmerging/policies/PreserveMethodCharacteristics.java b/src/main/java/com/android/tools/r8/horizontalclassmerging/policies/PreserveMethodCharacteristics.java
index 431fdb9..3adb35c 100644
--- a/src/main/java/com/android/tools/r8/horizontalclassmerging/policies/PreserveMethodCharacteristics.java
+++ b/src/main/java/com/android/tools/r8/horizontalclassmerging/policies/PreserveMethodCharacteristics.java
@@ -4,12 +4,14 @@
 
 package com.android.tools.r8.horizontalclassmerging.policies;
 
+import com.android.tools.r8.graph.AppView;
 import com.android.tools.r8.graph.DexEncodedMethod;
 import com.android.tools.r8.graph.DexMethodSignature;
 import com.android.tools.r8.graph.DexProgramClass;
 import com.android.tools.r8.graph.MethodAccessFlags;
 import com.android.tools.r8.horizontalclassmerging.MergeGroup;
 import com.android.tools.r8.horizontalclassmerging.MultiClassPolicy;
+import com.android.tools.r8.shaking.AppInfoWithLiveness;
 import com.android.tools.r8.utils.OptionalBool;
 import com.google.common.collect.Iterables;
 import java.util.ArrayList;
@@ -28,9 +30,10 @@
   static class MethodCharacteristics {
 
     private final MethodAccessFlags accessFlags;
+    private final boolean isAssumeNoSideEffectsMethod;
     private final OptionalBool isLibraryMethodOverride;
 
-    private MethodCharacteristics(DexEncodedMethod method) {
+    private MethodCharacteristics(boolean isAssumeNoSideEffectsMethod, DexEncodedMethod method) {
       this.accessFlags =
           MethodAccessFlags.builder()
               .setPrivate(method.getAccessFlags().isPrivate())
@@ -39,9 +42,16 @@
               .setStrict(method.getAccessFlags().isStrict())
               .setSynchronized(method.getAccessFlags().isSynchronized())
               .build();
+      this.isAssumeNoSideEffectsMethod = isAssumeNoSideEffectsMethod;
       this.isLibraryMethodOverride = method.isLibraryMethodOverride();
     }
 
+    static MethodCharacteristics create(
+        AppView<AppInfoWithLiveness> appView, DexEncodedMethod method) {
+      return new MethodCharacteristics(
+          appView.appInfo().isAssumeNoSideEffectsMethod(method.getReference()), method);
+    }
+
     @Override
     public int hashCode() {
       return (accessFlags.hashCode() << 2) | isLibraryMethodOverride.ordinal();
@@ -56,12 +66,17 @@
         return false;
       }
       MethodCharacteristics characteristics = (MethodCharacteristics) obj;
-      return isLibraryMethodOverride == characteristics.isLibraryMethodOverride
-          && accessFlags.equals(characteristics.accessFlags);
+      return accessFlags.equals(characteristics.accessFlags)
+          && isAssumeNoSideEffectsMethod == characteristics.isAssumeNoSideEffectsMethod
+          && isLibraryMethodOverride == characteristics.isLibraryMethodOverride;
     }
   }
 
-  public PreserveMethodCharacteristics() {}
+  private final AppView<AppInfoWithLiveness> appView;
+
+  public PreserveMethodCharacteristics(AppView<AppInfoWithLiveness> appView) {
+    this.appView = appView;
+  }
 
   public static class TargetGroup {
 
@@ -72,12 +87,12 @@
       return group;
     }
 
-    public boolean tryAdd(DexProgramClass clazz) {
+    public boolean tryAdd(AppView<AppInfoWithLiveness> appView, DexProgramClass clazz) {
       Map<DexMethodSignature, MethodCharacteristics> newMethods = new HashMap<>();
       for (DexEncodedMethod method : clazz.methods()) {
         DexMethodSignature signature = method.getSignature();
         MethodCharacteristics existingCharacteristics = methodMap.get(signature);
-        MethodCharacteristics methodCharacteristics = new MethodCharacteristics(method);
+        MethodCharacteristics methodCharacteristics = MethodCharacteristics.create(appView, method);
         if (existingCharacteristics == null) {
           newMethods.put(signature, methodCharacteristics);
           continue;
@@ -97,10 +112,10 @@
     List<TargetGroup> groups = new ArrayList<>();
 
     for (DexProgramClass clazz : group) {
-      boolean added = Iterables.any(groups, targetGroup -> targetGroup.tryAdd(clazz));
+      boolean added = Iterables.any(groups, targetGroup -> targetGroup.tryAdd(appView, clazz));
       if (!added) {
         TargetGroup newGroup = new TargetGroup();
-        added = newGroup.tryAdd(clazz);
+        added = newGroup.tryAdd(appView, clazz);
         assert added;
         groups.add(newGroup);
       }
diff --git a/src/main/java/com/android/tools/r8/ir/code/BasicBlockInstructionListIterator.java b/src/main/java/com/android/tools/r8/ir/code/BasicBlockInstructionListIterator.java
index ee770e8..a1c4e7b 100644
--- a/src/main/java/com/android/tools/r8/ir/code/BasicBlockInstructionListIterator.java
+++ b/src/main/java/com/android/tools/r8/ir/code/BasicBlockInstructionListIterator.java
@@ -4,6 +4,7 @@
 
 package com.android.tools.r8.ir.code;
 
+import static com.android.tools.r8.graph.DexProgramClass.asProgramClassOrNull;
 import static com.android.tools.r8.ir.analysis.type.Nullability.definitelyNotNull;
 import static com.android.tools.r8.ir.analysis.type.Nullability.maybeNull;
 import static com.android.tools.r8.ir.code.DominatorTree.Assumption.MAY_HAVE_UNREACHABLE_BLOCKS;
@@ -12,6 +13,9 @@
 import com.android.tools.r8.graph.AppView;
 import com.android.tools.r8.graph.DebugLocalInfo;
 import com.android.tools.r8.graph.DexField;
+import com.android.tools.r8.graph.DexItemFactory;
+import com.android.tools.r8.graph.DexMethod;
+import com.android.tools.r8.graph.DexProgramClass;
 import com.android.tools.r8.graph.DexString;
 import com.android.tools.r8.graph.DexType;
 import com.android.tools.r8.graph.ProgramMethod;
@@ -19,6 +23,7 @@
 import com.android.tools.r8.ir.analysis.type.TypeElement;
 import com.android.tools.r8.ir.code.Phi.RegisterReadType;
 import com.android.tools.r8.ir.optimize.NestUtils;
+import com.android.tools.r8.shaking.AppInfoWithLiveness;
 import com.android.tools.r8.utils.InternalOptions;
 import com.android.tools.r8.utils.IteratorUtils;
 import com.google.common.collect.ImmutableList;
@@ -269,6 +274,76 @@
   }
 
   @Override
+  public boolean replaceCurrentInstructionByNullCheckIfPossible(
+      AppView<?> appView, ProgramMethod context) {
+    Instruction toBeReplaced = current;
+    assert toBeReplaced != null;
+    assert toBeReplaced.isInstanceFieldInstruction() || toBeReplaced.isInvokeMethodWithReceiver();
+    if (toBeReplaced.hasUsedOutValue()) {
+      return false;
+    }
+    if (toBeReplaced.isInvokeDirect()) {
+      DexItemFactory dexItemFactory = appView.dexItemFactory();
+      DexMethod invokedMethod = toBeReplaced.asInvokeDirect().getInvokedMethod();
+      if (invokedMethod.isInstanceInitializer(dexItemFactory)
+          || invokedMethod.mustBeInlinedIntoInstanceInitializer(dexItemFactory)) {
+        return false;
+      }
+    }
+    if (toBeReplaced.instructionMayHaveSideEffects(
+        appView, context, Instruction.SideEffectAssumption.RECEIVER_NOT_NULL)) {
+      return false;
+    }
+    Value receiver =
+        toBeReplaced.isInstanceFieldInstruction()
+            ? toBeReplaced.asInstanceFieldInstruction().object()
+            : toBeReplaced.asInvokeMethodWithReceiver().getReceiver();
+    if (receiver.isNeverNull()) {
+      removeOrReplaceByDebugLocalRead();
+      return true;
+    }
+    InvokeMethod replacement;
+    if (appView.options().canUseRequireNonNull()) {
+      DexMethod requireNonNullMethod = appView.dexItemFactory().objectsMethods.requireNonNull;
+      replacement = new InvokeStatic(requireNonNullMethod, null, ImmutableList.of(receiver));
+    } else {
+      DexMethod getClassMethod = appView.dexItemFactory().objectMembers.getClass;
+      replacement = new InvokeVirtual(getClassMethod, null, ImmutableList.of(receiver));
+    }
+    replaceCurrentInstruction(replacement);
+    return true;
+  }
+
+  @Override
+  public boolean replaceCurrentInstructionByInitClassIfPossible(
+      AppView<AppInfoWithLiveness> appView, IRCode code, DexType type) {
+    Instruction toBeReplaced = current;
+    assert toBeReplaced != null;
+    assert toBeReplaced.isStaticFieldInstruction() || toBeReplaced.isInvokeStatic();
+    if (toBeReplaced.hasUsedOutValue()) {
+      return false;
+    }
+    ProgramMethod context = code.context();
+    if (toBeReplaced.instructionMayHaveSideEffects(
+        appView, context, Instruction.SideEffectAssumption.CLASS_ALREADY_INITIALIZED)) {
+      return false;
+    }
+    if (!type.classInitializationMayHaveSideEffectsInContext(appView, context)) {
+      removeOrReplaceByDebugLocalRead();
+      return true;
+    }
+    if (!appView.canUseInitClass()) {
+      return false;
+    }
+    DexProgramClass clazz = asProgramClassOrNull(appView.definitionFor(type));
+    if (clazz != null) {
+      Value dest = code.createValue(TypeElement.getInt());
+      replaceCurrentInstruction(new InitClass(dest, clazz.type));
+    }
+    return true;
+  }
+
+  @Override
   public void replaceCurrentInstructionWithConstClass(
       AppView<?> appView, IRCode code, DexType type, DebugLocalInfo localInfo) {
     if (current == null) {
diff --git a/src/main/java/com/android/tools/r8/ir/code/IRCodeInstructionListIterator.java b/src/main/java/com/android/tools/r8/ir/code/IRCodeInstructionListIterator.java
index a96760f..757a581 100644
--- a/src/main/java/com/android/tools/r8/ir/code/IRCodeInstructionListIterator.java
+++ b/src/main/java/com/android/tools/r8/ir/code/IRCodeInstructionListIterator.java
@@ -11,7 +11,9 @@
 import com.android.tools.r8.graph.DexField;
 import com.android.tools.r8.graph.DexString;
 import com.android.tools.r8.graph.DexType;
+import com.android.tools.r8.graph.ProgramMethod;
 import com.android.tools.r8.ir.analysis.type.TypeElement;
+import com.android.tools.r8.shaking.AppInfoWithLiveness;
 import com.android.tools.r8.utils.InternalOptions;
 import java.util.ListIterator;
 import java.util.NoSuchElementException;
@@ -42,6 +44,18 @@
   }
 
   @Override
+  public boolean replaceCurrentInstructionByNullCheckIfPossible(
+      AppView<?> appView, ProgramMethod context) {
+    return instructionIterator.replaceCurrentInstructionByNullCheckIfPossible(appView, context);
+  }
+
+  @Override
+  public boolean replaceCurrentInstructionByInitClassIfPossible(
+      AppView<AppInfoWithLiveness> appView, IRCode code, DexType type) {
+    return instructionIterator.replaceCurrentInstructionByInitClassIfPossible(appView, code, type);
+  }
+
+  @Override
   public void replaceCurrentInstructionWithConstClass(
       AppView<?> appView, IRCode code, DexType type, DebugLocalInfo localInfo) {
     instructionIterator.replaceCurrentInstructionWithConstClass(appView, code, type, localInfo);
diff --git a/src/main/java/com/android/tools/r8/ir/code/Instruction.java b/src/main/java/com/android/tools/r8/ir/code/Instruction.java
index e8ba6bd..689514f 100644
--- a/src/main/java/com/android/tools/r8/ir/code/Instruction.java
+++ b/src/main/java/com/android/tools/r8/ir/code/Instruction.java
@@ -130,7 +130,11 @@
   }
 
   public boolean hasUnusedOutValue() {
-    return !hasOutValue() || !outValue().hasAnyUsers();
+    return !hasUsedOutValue();
+  }
+
+  public boolean hasUsedOutValue() {
+    return hasOutValue() && outValue().hasAnyUsers();
   }
 
   public Value outValue() {
diff --git a/src/main/java/com/android/tools/r8/ir/code/InstructionListIterator.java b/src/main/java/com/android/tools/r8/ir/code/InstructionListIterator.java
index c4cceea..6b17a04 100644
--- a/src/main/java/com/android/tools/r8/ir/code/InstructionListIterator.java
+++ b/src/main/java/com/android/tools/r8/ir/code/InstructionListIterator.java
@@ -11,7 +11,9 @@
 import com.android.tools.r8.graph.DexField;
 import com.android.tools.r8.graph.DexString;
 import com.android.tools.r8.graph.DexType;
+import com.android.tools.r8.graph.ProgramMethod;
 import com.android.tools.r8.ir.analysis.type.TypeElement;
+import com.android.tools.r8.shaking.AppInfoWithLiveness;
 import com.android.tools.r8.utils.InternalOptions;
 import com.google.common.collect.Sets;
 import java.util.ListIterator;
@@ -97,6 +99,11 @@
 
   Value insertConstStringInstruction(AppView<?> appView, IRCode code, DexString value);
 
+  boolean replaceCurrentInstructionByNullCheckIfPossible(AppView<?> appView, ProgramMethod context);
+
+  boolean replaceCurrentInstructionByInitClassIfPossible(
+      AppView<AppInfoWithLiveness> appView, IRCode code, DexType type);
+
   void replaceCurrentInstructionWithConstClass(
       AppView<?> appView, IRCode code, DexType type, DebugLocalInfo localInfo);
 
diff --git a/src/main/java/com/android/tools/r8/ir/code/Invoke.java b/src/main/java/com/android/tools/r8/ir/code/Invoke.java
index 31fd8f4..5793ec1 100644
--- a/src/main/java/com/android/tools/r8/ir/code/Invoke.java
+++ b/src/main/java/com/android/tools/r8/ir/code/Invoke.java
@@ -144,6 +144,10 @@
 
   abstract public DexType getReturnType();
 
+  public boolean hasArguments() {
+    return !arguments().isEmpty();
+  }
+
   public boolean hasReturnTypeVoid(DexItemFactory factory) {
     return getReturnType() == factory.voidType;
   }
diff --git a/src/main/java/com/android/tools/r8/ir/code/LinearFlowInstructionListIterator.java b/src/main/java/com/android/tools/r8/ir/code/LinearFlowInstructionListIterator.java
index 0fc2768..bbb6d27 100644
--- a/src/main/java/com/android/tools/r8/ir/code/LinearFlowInstructionListIterator.java
+++ b/src/main/java/com/android/tools/r8/ir/code/LinearFlowInstructionListIterator.java
@@ -10,7 +10,9 @@
 import com.android.tools.r8.graph.DexField;
 import com.android.tools.r8.graph.DexString;
 import com.android.tools.r8.graph.DexType;
+import com.android.tools.r8.graph.ProgramMethod;
 import com.android.tools.r8.ir.analysis.type.TypeElement;
+import com.android.tools.r8.shaking.AppInfoWithLiveness;
 import com.android.tools.r8.utils.InternalOptions;
 import com.google.common.collect.Sets;
 import java.util.ListIterator;
@@ -62,6 +64,18 @@
   }
 
   @Override
+  public boolean replaceCurrentInstructionByNullCheckIfPossible(
+      AppView<?> appView, ProgramMethod context) {
+    return currentBlockIterator.replaceCurrentInstructionByNullCheckIfPossible(appView, context);
+  }
+
+  @Override
+  public boolean replaceCurrentInstructionByInitClassIfPossible(
+      AppView<AppInfoWithLiveness> appView, IRCode code, DexType type) {
+    return currentBlockIterator.replaceCurrentInstructionByInitClassIfPossible(appView, code, type);
+  }
+
+  @Override
   public void replaceCurrentInstructionWithConstClass(
       AppView<?> appView, IRCode code, DexType type, DebugLocalInfo localInfo) {
     currentBlockIterator.replaceCurrentInstructionWithConstClass(appView, code, type, localInfo);
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/Inliner.java b/src/main/java/com/android/tools/r8/ir/optimize/Inliner.java
index 7e75ee2..38c4e6f 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/Inliner.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/Inliner.java
@@ -982,6 +982,16 @@
             continue;
           }
 
+          if (invoke.isInvokeMethodWithReceiver()) {
+            if (iterator.replaceCurrentInstructionByNullCheckIfPossible(appView, context)) {
+              continue;
+            }
+          } else if (invoke.isInvokeStatic()
+              && iterator.replaceCurrentInstructionByInitClassIfPossible(
+                  appView, code, resolutionResult.getResolvedHolder().getType())) {
+            continue;
+          }
+
           // TODO(b/156853206): Should not duplicate resolution.
           ProgramMethod singleTarget = oracle.lookupSingleTarget(invoke, context);
           if (singleTarget == null) {
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/MemberValuePropagation.java b/src/main/java/com/android/tools/r8/ir/optimize/MemberValuePropagation.java
index 39ce729..2950d4c 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/MemberValuePropagation.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/MemberValuePropagation.java
@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 package com.android.tools.r8.ir.optimize;
 
-import static com.android.tools.r8.graph.DexProgramClass.asProgramClassOrNull;
 import static com.android.tools.r8.ir.analysis.type.Nullability.maybeNull;
 import static com.google.common.base.Predicates.alwaysTrue;
 
@@ -14,7 +13,6 @@
 import com.android.tools.r8.graph.DexEncodedMethod;
 import com.android.tools.r8.graph.DexField;
 import com.android.tools.r8.graph.DexMethod;
-import com.android.tools.r8.graph.DexProgramClass;
 import com.android.tools.r8.graph.DexReference;
 import com.android.tools.r8.graph.DexType;
 import com.android.tools.r8.graph.ProgramMethod;
@@ -26,13 +24,10 @@
 import com.android.tools.r8.ir.code.FieldInstruction;
 import com.android.tools.r8.ir.code.IRCode;
 import com.android.tools.r8.ir.code.IRMetadata;
-import com.android.tools.r8.ir.code.InitClass;
 import com.android.tools.r8.ir.code.InstancePut;
 import com.android.tools.r8.ir.code.Instruction;
 import com.android.tools.r8.ir.code.InstructionListIterator;
 import com.android.tools.r8.ir.code.InvokeMethod;
-import com.android.tools.r8.ir.code.InvokeStatic;
-import com.android.tools.r8.ir.code.InvokeVirtual;
 import com.android.tools.r8.ir.code.Position;
 import com.android.tools.r8.ir.code.StaticGet;
 import com.android.tools.r8.ir.code.StaticPut;
@@ -44,7 +39,6 @@
 import com.android.tools.r8.shaking.ProguardMemberRuleReturnValue;
 import com.android.tools.r8.utils.Reporter;
 import com.android.tools.r8.utils.StringDiagnostic;
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Sets;
 import java.util.ListIterator;
 import java.util.Set;
@@ -216,8 +210,8 @@
       }
       if (current.isStaticGet()) {
         StaticGet staticGet = current.asStaticGet();
-        replaceInstructionByInitClassIfPossible(
-            staticGet, staticGet.getField().holder, code, iterator, code.context());
+        iterator.replaceCurrentInstructionByInitClassIfPossible(
+            appView, code, staticGet.getField().holder);
       }
       replacement.setPosition(position);
       if (block.hasCatchHandlers()) {
@@ -236,16 +230,12 @@
       ListIterator<BasicBlock> blocks,
       InstructionListIterator iterator,
       InvokeMethod invoke) {
+    if (invoke.hasUnusedOutValue()) {
+      return;
+    }
+
     DexMethod invokedMethod = invoke.getInvokedMethod();
-    if (invokedMethod.proto.returnType.isVoidType()) {
-      return;
-    }
-
-    if (!invoke.hasOutValue() || !invoke.outValue().hasNonDebugUsers()) {
-      return;
-    }
-
-    DexType invokedHolder = invokedMethod.holder;
+    DexType invokedHolder = invokedMethod.getHolderType();
     if (!invokedHolder.isClassType()) {
       return;
     }
@@ -302,10 +292,10 @@
         invoke.setOutValue(null);
 
         if (invoke.isInvokeMethodWithReceiver()) {
-          replaceInstructionByNullCheckIfPossible(invoke, iterator, context);
+          iterator.replaceCurrentInstructionByNullCheckIfPossible(appView, context);
         } else if (invoke.isInvokeStatic()) {
-          replaceInstructionByInitClassIfPossible(
-              invoke, singleTarget.getHolderType(), code, iterator, context);
+          iterator.replaceCurrentInstructionByInitClassIfPossible(
+              appView, code, singleTarget.getHolderType());
         }
 
         // Insert the definition of the replacement.
@@ -404,11 +394,11 @@
         // To preserve side effects, original field-get is replaced by an explicit null-check, if
         // the field-get instruction may only fail with an NPE, or the field-get remains as-is.
         if (current.isInstanceGet()) {
-          replaceInstructionByNullCheckIfPossible(current, iterator, context);
+          iterator.replaceCurrentInstructionByNullCheckIfPossible(appView, context);
         } else {
           assert current.isStaticGet();
-          replaceInstructionByInitClassIfPossible(
-              current, target.getHolderType(), code, iterator, context);
+          iterator.replaceCurrentInstructionByInitClassIfPossible(
+              appView, code, target.getHolderType());
         }
 
         // Insert the definition of the replacement.
@@ -426,58 +416,6 @@
     }
   }
 
-  private void replaceInstructionByNullCheckIfPossible(
-      Instruction instruction, InstructionListIterator iterator, ProgramMethod context) {
-    assert instruction.isInstanceFieldInstruction() || instruction.isInvokeMethodWithReceiver();
-    assert !instruction.hasOutValue() || !instruction.outValue().hasAnyUsers();
-    if (instruction.instructionMayHaveSideEffects(
-        appView, context, Instruction.SideEffectAssumption.RECEIVER_NOT_NULL)) {
-      return;
-    }
-    Value receiver =
-        instruction.isInstanceFieldInstruction()
-            ? instruction.asInstanceFieldInstruction().object()
-            : instruction.asInvokeMethodWithReceiver().getReceiver();
-    if (receiver.isNeverNull()) {
-      iterator.removeOrReplaceByDebugLocalRead();
-      return;
-    }
-    InvokeMethod replacement;
-    if (appView.options().canUseRequireNonNull()) {
-      DexMethod requireNonNullMethod = appView.dexItemFactory().objectsMethods.requireNonNull;
-      replacement = new InvokeStatic(requireNonNullMethod, null, ImmutableList.of(receiver));
-    } else {
-      DexMethod getClassMethod = appView.dexItemFactory().objectMembers.getClass;
-      replacement = new InvokeVirtual(getClassMethod, null, ImmutableList.of(receiver));
-    }
-    iterator.replaceCurrentInstruction(replacement);
-  }
-
-  private void replaceInstructionByInitClassIfPossible(
-      Instruction instruction,
-      DexType holder,
-      IRCode code,
-      InstructionListIterator iterator,
-      ProgramMethod context) {
-    assert instruction.isStaticFieldInstruction() || instruction.isInvokeStatic();
-    if (instruction.instructionMayHaveSideEffects(
-        appView, context, Instruction.SideEffectAssumption.CLASS_ALREADY_INITIALIZED)) {
-      return;
-    }
-    if (!holder.classInitializationMayHaveSideEffectsInContext(appView, context)) {
-      iterator.removeOrReplaceByDebugLocalRead();
-      return;
-    }
-    if (!appView.canUseInitClass()) {
-      return;
-    }
-    DexProgramClass clazz = asProgramClassOrNull(appView.definitionFor(holder));
-    if (clazz != null) {
-      Value dest = code.createValue(TypeElement.getInt());
-      iterator.replaceCurrentInstruction(new InitClass(dest, clazz.type));
-    }
-  }
-
   private void replaceInstancePutByNullCheckIfNeverRead(
       IRCode code, InstructionListIterator iterator, InstancePut current) {
     DexEncodedField field = appView.appInfo().resolveField(current.getField()).getResolvedField();
@@ -492,7 +430,7 @@
       return;
     }
 
-    replaceInstructionByNullCheckIfPossible(current, iterator, code.context());
+    iterator.replaceCurrentInstructionByNullCheckIfPossible(appView, code.context());
   }
 
   private void replaceStaticPutByInitClassIfNeverRead(
@@ -509,8 +447,7 @@
       return;
     }
 
-    replaceInstructionByInitClassIfPossible(
-        current, field.getHolderType(), code, iterator, code.context());
+    iterator.replaceCurrentInstructionByInitClassIfPossible(appView, code, field.getHolderType());
   }
 
   /**
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/Outliner.java b/src/main/java/com/android/tools/r8/ir/optimize/Outliner.java
index 508e0f4..f673395 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/Outliner.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/Outliner.java
@@ -37,6 +37,7 @@
 import com.android.tools.r8.ir.analysis.type.PrimitiveTypeElement;
 import com.android.tools.r8.ir.analysis.type.TypeElement;
 import com.android.tools.r8.ir.code.Add;
+import com.android.tools.r8.ir.code.Assume;
 import com.android.tools.r8.ir.code.BasicBlock;
 import com.android.tools.r8.ir.code.BasicBlock.ThrowingInfo;
 import com.android.tools.r8.ir.code.Binop;
@@ -782,7 +783,7 @@
     // Process instruction. Returns true if an outline candidate was found.
     private void processInstruction(Instruction instruction) {
       // Figure out whether to include the instruction.
-      boolean include = false;
+      boolean include;
       int instructionIncrement = 1;
       if (instruction.isConstInstruction()) {
         if (index == start) {
@@ -811,13 +812,13 @@
         includeInstruction(instruction);
         // Check if this instruction ends the outline.
         if (actualInstructions >= appView.options().outline.maxSize) {
-          candidate(start, index + 1, actualInstructions);
+          candidate(start, index + 1);
         } else {
           index++;
         }
       } else if (index > start) {
         // Do not add this instruction, candidate ends with previous instruction.
-        candidate(start, index, actualInstructions);
+        candidate(start, index);
       } else {
         // Restart search from next instruction.
         reset(index + 1);
@@ -830,7 +831,7 @@
       int returnValueUsersLeftIfIncluded = returnValueUsersLeft;
       if (returnValue != null) {
         for (Value value : instruction.inValues()) {
-          if (value == returnValue) {
+          if (value.getAliasedValue() == returnValue) {
             returnValueUsersLeftIfIncluded--;
           }
         }
@@ -870,10 +871,9 @@
       }
       // Find the number of in-going arguments, if adding this instruction.
       int newArgumentRegisters = argumentRegisters;
-      if (instruction.inValues().size() > 0) {
-        List<Value> inValues = orderedInValues(instruction, returnValue);
-        for (int i = 0; i < inValues.size(); i++) {
-          Value value = inValues.get(i);
+      if (invoke.hasArguments()) {
+        for (int i = 0; i < invoke.arguments().size(); i++) {
+          Value value = invoke.getArgument(i).getAliasedValue();
           if (value == returnValue) {
             continue;
           }
@@ -884,7 +884,8 @@
             newArgumentRegisters += value.requiredRegisters();
           } else {
             // For virtual calls only re-use the receiver argument.
-            if (i > 0 || !arguments.contains(value)) {
+            Value receiver = invoke.asInvokeMethodWithReceiver().getReceiver().getAliasedValue();
+            if (value != receiver || !arguments.contains(value)) {
               newArgumentRegisters += value.requiredRegisters();
             }
           }
@@ -907,7 +908,11 @@
           offset++;
           previous = instructions.get(index - offset);
         } while (previous.isConstInstruction());
-        if (!previous.isNewInstance() || previous.outValue() != returnValue) {
+        if (!previous.isNewInstance()) {
+          return false;
+        }
+        if (returnValue == null || returnValue != previous.outValue()) {
+          assert false;
           return false;
         }
         // Clear pending new instance flag as the last thing, now the matching constructor is known
@@ -996,6 +1001,10 @@
     // Add the current instruction to the outline.
     private void includeInstruction(Instruction instruction) {
       if (instruction.isAssume()) {
+        Assume assume = instruction.asAssume();
+        if (returnValue != null && assume.src().getAliasedValue() == returnValue) {
+          adjustReturnValueUsersLeft(assume.outValue().numberOfAllUsers() - 1);
+        }
         return;
       }
 
@@ -1005,12 +1014,7 @@
       if (returnValue != null) {
         for (Value value : inValues) {
           if (value.getAliasedValue() == returnValue) {
-            assert returnValueUsersLeft > 0;
-            returnValueUsersLeft--;
-          }
-          if (returnValueUsersLeft == 0) {
-            returnValue = null;
-            returnType = appView.dexItemFactory().voidType;
+            adjustReturnValueUsersLeft(-1);
           }
         }
       }
@@ -1080,9 +1084,18 @@
       }
     }
 
+    private void adjustReturnValueUsersLeft(int change) {
+      returnValueUsersLeft += change;
+      assert returnValueUsersLeft >= 0;
+      if (returnValueUsersLeft == 0) {
+        returnValue = null;
+        returnType = appView.dexItemFactory().voidType;
+      }
+    }
+
     protected abstract void handle(int start, int end, Outline outline);
 
-    private void candidate(int start, int index, int actualInstructions) {
+    private void candidate(int start, int index) {
       List<Instruction> instructions = getInstructionArray();
       assert !instructions.get(start).isConstInstruction();
 
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java b/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
index 143d776..0ce08a5 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/classinliner/InlineCandidateProcessor.java
@@ -584,10 +584,13 @@
       currentUsers = indirectOutValueUsers;
     }
 
-    assert !methodCallsOnInstance.isEmpty();
-
-    inliner.performForcedInlining(
-        method, code, methodCallsOnInstance, inliningIRProvider, Timing.empty());
+    if (!methodCallsOnInstance.isEmpty()) {
+      inliner.performForcedInlining(
+          method, code, methodCallsOnInstance, inliningIRProvider, Timing.empty());
+    } else {
+      assert indirectMethodCallsOnInstance.stream()
+          .noneMatch(method -> method.getDefinition().getOptimizationInfo().mayHaveSideEffects());
+    }
     return true;
   }
 
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/library/LibraryMethodSideEffectModelCollection.java b/src/main/java/com/android/tools/r8/ir/optimize/library/LibraryMethodSideEffectModelCollection.java
index b1890af..ae91ac8 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/library/LibraryMethodSideEffectModelCollection.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/library/LibraryMethodSideEffectModelCollection.java
@@ -38,7 +38,10 @@
         ImmutableMap.<DexMethod, BiPredicate<DexMethod, List<Value>>>builder()
             .put(
                 dexItemFactory.stringMembers.constructor,
-                (method, arguments) -> arguments.get(1).isNeverNull());
+                (method, arguments) -> arguments.get(1).isNeverNull())
+            .put(
+                dexItemFactory.stringMembers.valueOf,
+                (method, arguments) -> arguments.get(0).isNeverNull());
     putAll(
         builder,
         dexItemFactory.stringBufferMethods.constructorMethods,
diff --git a/src/main/java/com/android/tools/r8/shaking/AppInfoWithLiveness.java b/src/main/java/com/android/tools/r8/shaking/AppInfoWithLiveness.java
index 97b2504..5619d97 100644
--- a/src/main/java/com/android/tools/r8/shaking/AppInfoWithLiveness.java
+++ b/src/main/java/com/android/tools/r8/shaking/AppInfoWithLiveness.java
@@ -575,6 +575,10 @@
     return neverInlineDueToSingleCaller.contains(method.getReference());
   }
 
+  public boolean isAssumeNoSideEffectsMethod(DexMethod method) {
+    return noSideEffects.containsKey(method);
+  }
+
   public boolean isWhyAreYouNotInliningMethod(DexMethod method) {
     return whyAreYouNotInlining.contains(method);
   }
diff --git a/src/test/java/com/android/tools/r8/ir/conversion/StringSwitchConversionFromIfTest.java b/src/test/java/com/android/tools/r8/ir/conversion/StringSwitchConversionFromIfTest.java
index 294efee..bcdd93f 100644
--- a/src/test/java/com/android/tools/r8/ir/conversion/StringSwitchConversionFromIfTest.java
+++ b/src/test/java/com/android/tools/r8/ir/conversion/StringSwitchConversionFromIfTest.java
@@ -7,7 +7,7 @@
 import static com.android.tools.r8.utils.codeinspector.Matchers.isPresent;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
 
 import com.android.tools.r8.NeverInline;
 import com.android.tools.r8.TestBase;
@@ -87,7 +87,16 @@
                 // instruction may throw. This holds even if the string-switch instruction is
                 // compiled to a sequence of `if (x.equals("..."))` instructions that do not even
                 // use the hash code.
-                assertNotEquals(0, hashCodeValues.size());
+                assertTrue(
+                    code.collectArguments().get(0).uniqueUsers().stream()
+                        .filter(Instruction::isInvokeMethod)
+                        .map(Instruction::asInvokeMethod)
+                        .map(invoke -> invoke.getInvokedMethod().getName().toSourceString())
+                        .anyMatch(
+                            name ->
+                                name.equals("getClass")
+                                    || name.equals("hashCode")
+                                    || name.equals("requireNonNull")));
               }
             })
         .run(parameters.getRuntime(), TestClass.class)
diff --git a/src/test/java/com/android/tools/r8/ir/optimize/R8InliningTest.java b/src/test/java/com/android/tools/r8/ir/optimize/R8InliningTest.java
index af047b9..7049089 100644
--- a/src/test/java/com/android/tools/r8/ir/optimize/R8InliningTest.java
+++ b/src/test/java/com/android/tools/r8/ir/optimize/R8InliningTest.java
@@ -3,6 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.
 package com.android.tools.r8.ir.optimize;
 
+import static com.android.tools.r8.utils.codeinspector.Matchers.isAbsent;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
@@ -333,7 +335,7 @@
     assertCounters(INLINABLE, NEVER_INLINABLE, countInvokes(inspector, m));
 
     m = clazz.method("int", "notInlinableDueToMissingNpe", ImmutableList.of("inlining.A"));
-    assertCounters(INLINABLE, NEVER_INLINABLE, countInvokes(inspector, m));
+    assertCounters(INLINABLE, ALWAYS_INLINABLE, countInvokes(inspector, m));
 
     m = clazz.method("int", "notInlinableDueToSideEffect", ImmutableList.of("inlining.A"));
     assertCounters(INLINABLE, NEVER_INLINABLE, countInvokes(inspector, m));
@@ -354,7 +356,12 @@
     CodeInspector inspector =
         new CodeInspector(getGeneratedFiles(), getGeneratedProguardMap(), null);
     ClassSubject clazz = inspector.clazz(nullabilityClass);
-    MethodSubject m = clazz.method("int", "conditionalOperator", ImmutableList.of("inlining.A"));
+    assertThat(clazz.uniqueMethodWithName("conditionalOperator"), isAbsent());
+
+    // The enum parameter may get unboxed.
+    MethodSubject m =
+        clazz.uniqueMethodWithName(
+            parameters.isCfRuntime() ? "moreControlFlows" : "moreControlFlows$enumunboxing$");
     assertTrue(m.isPresent());
 
     // Verify that a.b() is resolved to an inline instance-get.
@@ -365,27 +372,6 @@
       InstructionSubject instruction = iterator.next();
       if (instruction.isInstanceGet()) {
         ++instanceGetCount;
-      } else if (instruction.isInvoke()) {
-        ++invokeCount;
-      }
-    }
-    assertEquals(1, instanceGetCount);
-    assertEquals(0, invokeCount);
-
-    // The enum parameter may get unboxed.
-    m =
-        clazz.uniqueMethodWithName(
-            parameters.isCfRuntime() ? "moreControlFlows" : "moreControlFlows$enumunboxing$");
-    assertTrue(m.isPresent());
-
-    // Verify that a.b() is resolved to an inline instance-get.
-    iterator = m.iterateInstructions();
-    instanceGetCount = 0;
-    invokeCount = 0;
-    while (iterator.hasNext()) {
-      InstructionSubject instruction = iterator.next();
-      if (instruction.isInstanceGet()) {
-        ++instanceGetCount;
       } else if (instruction.isInvoke() && !isEnumInvoke(instruction)) {
         ++invokeCount;
       }
diff --git a/src/test/java/com/android/tools/r8/ir/regalloc/RegisterMoveSchedulerTest.java b/src/test/java/com/android/tools/r8/ir/regalloc/RegisterMoveSchedulerTest.java
index c253c45..8d01a11 100644
--- a/src/test/java/com/android/tools/r8/ir/regalloc/RegisterMoveSchedulerTest.java
+++ b/src/test/java/com/android/tools/r8/ir/regalloc/RegisterMoveSchedulerTest.java
@@ -14,6 +14,7 @@
 import com.android.tools.r8.graph.DexField;
 import com.android.tools.r8.graph.DexString;
 import com.android.tools.r8.graph.DexType;
+import com.android.tools.r8.graph.ProgramMethod;
 import com.android.tools.r8.ir.analysis.type.Nullability;
 import com.android.tools.r8.ir.analysis.type.TypeElement;
 import com.android.tools.r8.ir.code.BasicBlock;
@@ -23,6 +24,7 @@
 import com.android.tools.r8.ir.code.Move;
 import com.android.tools.r8.ir.code.Value;
 import com.android.tools.r8.ir.code.ValueType;
+import com.android.tools.r8.shaking.AppInfoWithLiveness;
 import com.android.tools.r8.utils.InternalOptions;
 import java.util.LinkedList;
 import java.util.List;
@@ -62,6 +64,18 @@
     }
 
     @Override
+    public boolean replaceCurrentInstructionByNullCheckIfPossible(
+        AppView<?> appView, ProgramMethod context) {
+      throw new Unimplemented();
+    }
+
+    @Override
+    public boolean replaceCurrentInstructionByInitClassIfPossible(
+        AppView<AppInfoWithLiveness> appView, IRCode code, DexType type) {
+      throw new Unimplemented();
+    }
+
+    @Override
     public void replaceCurrentInstructionWithConstClass(
         AppView<?> appView, IRCode code, DexType type, DebugLocalInfo localInfo) {
       throw new Unimplemented();
diff --git a/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumeNoSideEffectsForJavaLangClassTest.java b/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumeNoSideEffectsForJavaLangClassTest.java
index eb29f88..fed4e6d 100644
--- a/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumeNoSideEffectsForJavaLangClassTest.java
+++ b/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumeNoSideEffectsForJavaLangClassTest.java
@@ -7,6 +7,7 @@
 import static com.android.tools.r8.utils.codeinspector.CodeMatchers.invokesMethodWithName;
 import static com.android.tools.r8.utils.codeinspector.Matchers.isPresent;
 import static com.android.tools.r8.utils.codeinspector.Matchers.onlyIf;
+import static org.hamcrest.CoreMatchers.anyOf;
 import static org.hamcrest.MatcherAssert.assertThat;
 
 import com.android.tools.r8.AssumeMayHaveSideEffects;
@@ -71,7 +72,11 @@
     assertThat(
         methodSubject,
         onlyIf(maybeNullReceiver || maybeSubtype, invokesMethodWithName("hashCode")));
-    assertThat(methodSubject, onlyIf(maybeNullReceiver, invokesMethodWithName("getClass")));
+    assertThat(
+        methodSubject,
+        onlyIf(
+            maybeNullReceiver,
+            anyOf(invokesMethodWithName("getClass"), invokesMethodWithName("requireNonNull"))));
     assertThat(
         methodSubject,
         onlyIf(maybeNullReceiver || maybeSubtype, invokesMethodWithName("toString")));
diff --git a/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumenosideeffectsPropagationTest.java b/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumenosideeffectsPropagationTest.java
index 1c7f6ac..8130a6f 100644
--- a/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumenosideeffectsPropagationTest.java
+++ b/src/test/java/com/android/tools/r8/shaking/assumenosideeffects/AssumenosideeffectsPropagationTest.java
@@ -111,7 +111,7 @@
   private final TestConfig config;
   private final boolean enableHorizontalClassMerging;
 
-  @Parameterized.Parameters(name = "{0} {1}")
+  @Parameterized.Parameters(name = "{0}, config: {1}, horizontal: {2}")
   public static Collection<Object[]> data() {
     return buildParameters(
         getTestParameters().withAllRuntimesAndApiLevels().build(),
diff --git a/src/test/java/com/android/tools/r8/smali/OutlineTest.java b/src/test/java/com/android/tools/r8/smali/OutlineTest.java
index e85f2d8..04ac085 100644
--- a/src/test/java/com/android/tools/r8/smali/OutlineTest.java
+++ b/src/test/java/com/android/tools/r8/smali/OutlineTest.java
@@ -252,7 +252,7 @@
             "    move-result-object  v0",
             "    invoke-virtual      { v0, v1 }, " + stringBuilderAppendSignature,
             "    move-result-object  v0",
-            "    invoke-virtual      { v0 }, " + stringBuilderToStringSignature,
+            "    invoke-virtual      { v0, v1 }, " + stringBuilderAppendSignature,
             "    move-result-object  v0",
             "    const               v0, 0",
             "    const               v1, 1",
@@ -818,7 +818,7 @@
         "    move-result-object  v0",
         "    invoke-virtual      { v0, v1 }, " + stringBuilderAppendSignature,
         "    move-result-object  v0",
-        "    invoke-virtual      { v0 }, " + stringBuilderToStringSignature,
+        "    invoke-virtual      { v0, v1 }, " + stringBuilderAppendSignature,
         "    return-void");
 
     String returnType2 = "java.lang.String";
@@ -866,14 +866,14 @@
     ClassSubject clazz = inspector.clazz(OutlineOptions.CLASS_NAME);
     assertTrue(clazz.isPresent());
     assertEquals(3, clazz.getDexProgramClass().getMethodCollection().numberOfDirectMethods());
-    // Collect the return types of the putlines for the body of method1 and method2.
+    // Collect the return types of the outlines for the body of method1 and method2.
     List<DexType> r = new ArrayList<>();
     for (DexEncodedMethod directMethod : clazz.getDexProgramClass().directMethods()) {
       if (directMethod.getCode().asDexCode().instructions[0] instanceof InvokeVirtual) {
         r.add(directMethod.method.proto.returnType);
       }
     }
-    assert r.size() == 2;
+    assertEquals(2, r.size());
     DexType r1 = r.get(0);
     DexType r2 = r.get(1);
     DexItemFactory factory = inspector.getFactory();
@@ -882,7 +882,7 @@
 
     // Run the code.
     String result = runArt(processedApplication);
-    assertEquals("TestTestTestTest", result);
+    assertEquals("TestTestTestTestTest", result);
   }
 
   @Test