From 26a4f1e6033941fd3b309f7c50423ed8559a848d Mon Sep 17 00:00:00 2001
From: Ben Gruver <bgruv@google.com>
Date: Sun, 11 Sep 2016 11:14:27 -0700
Subject: [PATCH] Fix an issue with instance-of type inference

We should only infer the register type after an if-eqz/nez if it has a
single predecessor that is the instance-of instruction.
---
 .../java/org/jf/dexlib2/analysis/AnalyzedInstruction.java    | 3 ++-
 .../main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java    | 5 ++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java b/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java
index be7b20f5..111913cc 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java
@@ -368,7 +368,8 @@ public class AnalyzedInstruction implements Comparable<AnalyzedInstruction> {
             return false;
         }
 
-        if (instruction.getOpcode() == Opcode.IF_EQZ || instruction.getOpcode() == Opcode.IF_NEZ) {
+        if (getPredecessorCount() == 1 && (instruction.getOpcode() == Opcode.IF_EQZ ||
+                instruction.getOpcode() == Opcode.IF_NEZ)) {
             AnalyzedInstruction previousInstruction = getPreviousInstruction();
             if (previousInstruction != null &&
                     previousInstruction.instruction.getOpcode() == Opcode.INSTANCE_OF &&
diff --git a/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java b/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java
index 6c99db38..64275402 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java
@@ -1206,7 +1206,10 @@ public class MethodAnalyzer {
     private void analyzeIfEqzNez(@Nonnull AnalyzedInstruction analyzedInstruction) {
         int instructionIndex = analyzedInstruction.getInstructionIndex();
         if (instructionIndex > 0) {
-            AnalyzedInstruction prevAnalyzedInstruction = analyzedInstructions.valueAt(instructionIndex - 1);
+            if (analyzedInstruction.getPredecessorCount() != 1) {
+                return;
+            }
+            AnalyzedInstruction prevAnalyzedInstruction = analyzedInstruction.getPredecessors().first();
             if (prevAnalyzedInstruction.instruction.getOpcode() == Opcode.INSTANCE_OF) {
                 if (canNarrowAfterInstanceOf(prevAnalyzedInstruction, analyzedInstruction, classPath)) {
                     List<Integer> narrowingRegisters = Lists.newArrayList();