From 7cd01f5d496c384874ea8c21eafb2b6479833e6a Mon Sep 17 00:00:00 2001
From: Vladimir Marko <vmarko@google.com>
Date: Mon, 13 Oct 2014 18:29:44 +0100
Subject: Add regression test for null check elimination.

Prompted by
    https://android-review.googlesource.com/110090

Bug: 17969907
Change-Id: I938c27cda0681b9431d69baf4eafa7ca2f9b5c9c
---
 compiler/dex/mir_optimization.cc            |  2 ++
 test/083-compiler-regressions/expected.txt  |  1 +
 test/083-compiler-regressions/src/Main.java | 19 +++++++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index 2ac0b51a89..84c056daf3 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -929,6 +929,8 @@ bool MIRGraph::EliminateNullChecks(BasicBlock* bb) {
         mir->optimization_flags |= MIR_IGNORE_NULL_CHECK;
       } else {
         // Do the null check.
+        // TODO: Rewrite the pass to converge first before doing any modifications so that
+        // we don't lose the MIR_IGNORE_NULL_CHECK here if previously set by some other pass.
         mir->optimization_flags &= ~MIR_IGNORE_NULL_CHECK;
         // Mark s_reg as null-checked
         ssa_regs_to_check->ClearBit(src_sreg);
diff --git a/test/083-compiler-regressions/expected.txt b/test/083-compiler-regressions/expected.txt
index e907fd1d58..c43d1f78cb 100644
--- a/test/083-compiler-regressions/expected.txt
+++ b/test/083-compiler-regressions/expected.txt
@@ -16,6 +16,7 @@ false
 b13679511Test finishing
 b16177324TestWrapper caught NPE as expected.
 b16230771TestWrapper caught NPE as expected.
+b17969907TestWrapper caught NPE as expected.
 largeFrame passes
 largeFrameFloat passes
 mulBy1Test passes
diff --git a/test/083-compiler-regressions/src/Main.java b/test/083-compiler-regressions/src/Main.java
index 8d7bf01192..9c772b9fb0 100644
--- a/test/083-compiler-regressions/src/Main.java
+++ b/test/083-compiler-regressions/src/Main.java
@@ -38,6 +38,7 @@ public class Main {
         b13679511Test();
         b16177324TestWrapper();
         b16230771TestWrapper();
+        b17969907TestWrapper();
         largeFrameTest();
         largeFrameTestFloat();
         mulBy1Test();
@@ -977,6 +978,24 @@ public class Main {
       }
     }
 
+    static void b17969907TestWrapper() {
+      try {
+        b17969907Test();
+        System.out.println("b17969907Test unexpectedly didn't throw NPE.");
+      } catch (NullPointerException expected) {
+        System.out.println("b17969907TestWrapper caught NPE as expected.");
+      }
+    }
+
+    public static void b17969907Test() {
+      Integer i = new Integer(1);
+      int sum = 0;
+      while (sum < 100) {
+        sum += i;
+        i = null;
+      }
+    }
+
     static double TooManyArgs(
           long l00,
           long l01,
-- 
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