Fix inlining in the presence of multiple returns.

One return could actually return a phi, so doing a phi check for
knowing if the result phi was already created was bogus.

Bug: 19454010

Change-Id: Iee703a2d1071ae263092354465eda368e5d6770d
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 93787b8..e51bbc3 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -893,28 +893,32 @@
     exit_block_->ReplaceWith(to);
 
     // Update all predecessors of the exit block (now the `to` block)
-    // to not `HReturn` but `HGoto` instead. Also collect the return
-    // values if any, and potentially make it a phi if there are multiple
-    // predecessors.
+    // to not `HReturn` but `HGoto` instead.
     HInstruction* return_value = nullptr;
-    for (size_t i = 0, e = to->GetPredecessors().Size(); i < e; ++i) {
-      HBasicBlock* predecessor = to->GetPredecessors().Get(i);
+    bool returns_void = to->GetPredecessors().Get(0)->GetLastInstruction()->IsReturnVoid();
+    if (to->GetPredecessors().Size() == 1) {
+      HBasicBlock* predecessor = to->GetPredecessors().Get(0);
       HInstruction* last = predecessor->GetLastInstruction();
-      if (!last->IsReturnVoid()) {
-        if (return_value != nullptr) {
-          if (!return_value->IsPhi()) {
-            HPhi* phi = new (allocator) HPhi(allocator, kNoRegNumber, 0, invoke->GetType());
-            to->AddPhi(phi);
-            phi->AddInput(return_value);
-            return_value = phi;
-          }
-          return_value->AsPhi()->AddInput(last->InputAt(0));
-        } else {
-          return_value = last->InputAt(0);
-        }
+      if (!returns_void) {
+        return_value = last->InputAt(0);
       }
       predecessor->AddInstruction(new (allocator) HGoto());
       predecessor->RemoveInstruction(last);
+    } else {
+      if (!returns_void) {
+        // There will be multiple returns.
+        return_value = new (allocator) HPhi(allocator, kNoRegNumber, 0, invoke->GetType());
+        to->AddPhi(return_value->AsPhi());
+      }
+      for (size_t i = 0, e = to->GetPredecessors().Size(); i < e; ++i) {
+        HBasicBlock* predecessor = to->GetPredecessors().Get(i);
+        HInstruction* last = predecessor->GetLastInstruction();
+        if (!returns_void) {
+          return_value->AsPhi()->AddInput(last->InputAt(0));
+        }
+        predecessor->AddInstruction(new (allocator) HGoto());
+        predecessor->RemoveInstruction(last);
+      }
     }
 
     if (return_value != nullptr) {
diff --git a/test/452-multiple-returns2/expected.txt b/test/452-multiple-returns2/expected.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/test/452-multiple-returns2/expected.txt
diff --git a/test/452-multiple-returns2/info.txt b/test/452-multiple-returns2/info.txt
new file mode 100644
index 0000000..cdd354b
--- /dev/null
+++ b/test/452-multiple-returns2/info.txt
@@ -0,0 +1,2 @@
+Tests inlining of a pattern not generated by DX: multiple
+returns in a single method.
diff --git a/test/452-multiple-returns2/smali/MultipleReturns.smali b/test/452-multiple-returns2/smali/MultipleReturns.smali
new file mode 100644
index 0000000..ff2b9b0
--- /dev/null
+++ b/test/452-multiple-returns2/smali/MultipleReturns.smali
@@ -0,0 +1,40 @@
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+.class public LMultipleReturns;
+
+.super Ljava/lang/Object;
+
+.method public static caller()I
+   .registers 1
+   invoke-static {},  LMultipleReturns;->$opt$CalleeReturnInt()I
+   move-result v0
+   return v0
+.end method
+
+.method public static $opt$CalleeReturnInt()I
+   .registers 2
+   const/4 v0, 0x0
+   const/4 v1, 0x1
+   if-eq v1, v0, :else
+   if-eq v1, v0, :else2
+   const/4 v0, 0x4
+   :else2
+   return v0
+   :else
+   if-eq v1, v0, :else3
+   const/4 v1, 0x3
+   :else3
+   return v1
+.end method
diff --git a/test/452-multiple-returns2/src/Main.java b/test/452-multiple-returns2/src/Main.java
new file mode 100644
index 0000000..8904c45
--- /dev/null
+++ b/test/452-multiple-returns2/src/Main.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Method;
+
+public class Main {
+
+  // Workaround for b/18051191.
+  class InnerClass {}
+
+  public static void main(String[] args) throws Exception {
+    Class<?> c = Class.forName("MultipleReturns");
+    Method m = c.getMethod("caller");
+    int result = (Integer)m.invoke(null);
+    if (result != 4) {
+      throw new Error("Expected 4, got " + result);
+    }
+  }
+}