Remove the no-longer-needed F/I and D/J alias.

Rationale:
Now that our HIR is type clean (yeah!), we no longer have
to conservatively assume F/I and D/J are aliased. This
enables more accurate side effects analysis, with improvements
in all clients, such a LICM.

Refinement:
The HIR is not completely clean between building and SSA.
This refinement takes care of that, with new tests.

BUG=22538329

Change-Id: Id78ff0ff4e325aeebf0022d868937cff73d3a742
diff --git a/test/594-checker-array-alias/src/Main.java b/test/594-checker-array-alias/src/Main.java
new file mode 100644
index 0000000..5ece2e2
--- /dev/null
+++ b/test/594-checker-array-alias/src/Main.java
@@ -0,0 +1,255 @@
+/*
+ * 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.util.Arrays;
+
+//
+// Test on array parameters with or without potential aliasing.
+//
+public class Main {
+
+  //
+  // Cross-over on parameters with potential aliasing on parameters.
+  // The arrays a and b may point to the same memory, which (without
+  // further runtime tests) prevents hoisting the seemingly invariant
+  // array reference.
+  //
+
+  /// CHECK-START: void Main.CrossOverLoop1(int[], int[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.CrossOverLoop1(int[], int[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void CrossOverLoop1(int a[], int b[]) {
+    b[20] = 99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = b[20] - 7;
+    }
+  }
+
+  /// CHECK-START: void Main.CrossOverLoop2(float[], float[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.CrossOverLoop2(float[], float[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void CrossOverLoop2(float a[], float b[]) {
+    b[20] = 99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = b[20] - 7;
+    }
+  }
+
+  /// CHECK-START: void Main.CrossOverLoop3(long[], long[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.CrossOverLoop3(long[], long[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void CrossOverLoop3(long a[], long b[]) {
+    b[20] = 99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = b[20] - 7;
+    }
+  }
+
+  /// CHECK-START: void Main.CrossOverLoop4(double[], double[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.CrossOverLoop4(double[], double[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void CrossOverLoop4(double a[], double b[]) {
+    b[20] = 99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = b[20] - 7;
+    }
+  }
+
+  //
+  // False cross-over on parameters. Parameters have same width (which used to
+  // cause a false type aliasing in an older version of the compiler), but since
+  // the types are different cannot be aliased. Thus, the invariant array
+  // reference can be hoisted.
+  //
+
+  /// CHECK-START: void Main.FalseCrossOverLoop1(int[], float[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.FalseCrossOverLoop1(int[], float[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:none
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void FalseCrossOverLoop1(int a[], float b[]) {
+    b[20] = -99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = (int) b[20] - 7;
+    }
+  }
+
+  /// CHECK-START: void Main.FalseCrossOverLoop2(float[], int[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.FalseCrossOverLoop2(float[], int[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:none
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void FalseCrossOverLoop2(float a[], int b[]) {
+    b[20] = -99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = b[20] - 7;
+    }
+  }
+
+  /// CHECK-START: void Main.FalseCrossOverLoop3(long[], double[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.FalseCrossOverLoop3(long[], double[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:none
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void FalseCrossOverLoop3(long a[], double b[]) {
+    b[20] = -99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = (long) b[20] - 7;
+    }
+  }
+
+  /// CHECK-START: void Main.FalseCrossOverLoop4(double[], long[]) licm (before)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:{{B\d+}}
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  //
+  /// CHECK-START: void Main.FalseCrossOverLoop4(double[], long[]) licm (after)
+  /// CHECK-DAG: ArraySet loop:none
+  /// CHECK-DAG: ArrayGet loop:none
+  /// CHECK-DAG: ArraySet loop:{{B\d+}}
+  private static void FalseCrossOverLoop4(double a[], long b[]) {
+    b[20] = -99;
+    for (int i = 0; i < a.length; i++) {
+      a[i] = b[20] - 7;
+    }
+  }
+
+  //
+  // Main driver and testers.
+  //
+
+  public static void main(String[] args) {
+    int[] aI = new int[100];
+    float[] aF = new float[100];
+    long[] aJ = new long[100];
+    double[] aD = new double[100];
+
+    // Type I.
+    CrossOverLoop1(aI, aI);
+    for (int i = 0; i < aI.length; i++) {
+      expectEquals(i <= 20 ? 92 : 85, aI[i]);
+    }
+    // Type F.
+    CrossOverLoop2(aF, aF);
+    for (int i = 0; i < aF.length; i++) {
+      expectEquals(i <= 20 ? 92 : 85, aF[i]);
+    }
+    // Type J.
+    CrossOverLoop3(aJ, aJ);
+    for (int i = 0; i < aJ.length; i++) {
+      expectEquals(i <= 20 ? 92 : 85, aJ[i]);
+    }
+    // Type D.
+    CrossOverLoop4(aD, aD);
+    for (int i = 0; i < aD.length; i++) {
+      expectEquals(i <= 20 ? 92 : 85, aD[i]);
+    }
+
+    // Type I vs F.
+    FalseCrossOverLoop1(aI, aF);
+    for (int i = 0; i < aI.length; i++) {
+      expectEquals(-106, aI[i]);
+    }
+    // Type F vs I.
+    FalseCrossOverLoop2(aF, aI);
+    for (int i = 0; i < aF.length; i++) {
+      expectEquals(-106, aF[i]);
+    }
+    // Type J vs D.
+    FalseCrossOverLoop3(aJ, aD);
+    for (int i = 0; i < aJ.length; i++) {
+      expectEquals(-106, aJ[i]);
+    }
+    // Type D vs J.
+    FalseCrossOverLoop4(aD, aJ);
+    for (int i = 0; i < aD.length; i++) {
+      expectEquals(-106, aD[i]);
+    }
+
+    // Real-world example where incorrect type assignment could introduce a bug.
+    // The library sorting algorithm is heavy on array reads and writes, and
+    // assigning the wrong J/D type to one of these would introduce errors.
+    for (int i = 0; i < aD.length; i++) {
+      aD[i] = aD.length - i - 1;
+    }
+    Arrays.sort(aD);
+    for (int i = 0; i < aD.length; i++) {
+      expectEquals((double) i, aD[i]);
+    }
+
+    System.out.println("passed");
+  }
+
+  private static void expectEquals(int expected, int result) {
+    if (expected != result) {
+      throw new Error("Expected: " + expected + ", found: " + result);
+    }
+  }
+
+  private static void expectEquals(long expected, long result) {
+    if (expected != result) {
+      throw new Error("Expected: " + expected + ", found: " + result);
+    }
+  }
+
+  private static void expectEquals(float expected, float result) {
+    if (expected != result) {
+      throw new Error("Expected: " + expected + ", found: " + result);
+    }
+  }
+
+  private static void expectEquals(double expected, double result) {
+    if (expected != result) {
+      throw new Error("Expected: " + expected + ", found: " + result);
+    }
+  }
+}