Fix target block index offset in switch eliminator
Bug: 181320553
Change-Id: I8d8347006e618bb9b72f2580bc2d3b8819fe96af
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/SwitchCaseEliminator.java b/src/main/java/com/android/tools/r8/ir/optimize/SwitchCaseEliminator.java
index 733db77..6c9bfbb 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/SwitchCaseEliminator.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/SwitchCaseEliminator.java
@@ -83,20 +83,20 @@
boolean optimize() {
if (canBeOptimized()) {
int originalNumberOfSuccessors = block.getSuccessors().size();
- unlinkDeadSuccessors();
+ IntList removedSuccessorIndices = unlinkDeadSuccessors();
if (hasAlwaysHitCase() || allSwitchCasesMarkedForRemoval()) {
// Replace switch with a simple goto.
replaceSwitchByGoto();
} else {
// Replace switch by a new switch where the dead switch cases have been removed.
- replaceSwitchByOptimizedSwitch(originalNumberOfSuccessors);
+ replaceSwitchByOptimizedSwitch(originalNumberOfSuccessors, removedSuccessorIndices);
}
return true;
}
return false;
}
- private void unlinkDeadSuccessors() {
+ private IntList unlinkDeadSuccessors() {
IntPredicate successorHasBecomeDeadPredicate = computeSuccessorHasBecomeDeadPredicate();
IntList successorIndicesToBeRemoved = new IntArrayList();
for (int i = 0; i < block.getSuccessors().size(); i++) {
@@ -111,6 +111,7 @@
}
successorIndicesToBeRemoved.sort(Comparator.naturalOrder());
block.removeSuccessorsByIndex(successorIndicesToBeRemoved);
+ return successorIndicesToBeRemoved;
}
private IntPredicate computeSuccessorHasBecomeDeadPredicate() {
@@ -136,16 +137,12 @@
iterator.replaceCurrentInstruction(new Goto(target));
}
- private void replaceSwitchByOptimizedSwitch(int originalNumberOfSuccessors) {
+ private void replaceSwitchByOptimizedSwitch(
+ int originalNumberOfSuccessors, IntList removedSuccessorIndices) {
int[] targetBlockIndexOffset = new int[originalNumberOfSuccessors];
- for (int i : switchCasesToBeRemoved) {
- int targetBlockIndex = theSwitch.getTargetBlockIndex(i);
- // Add 1 because we are interested in the number of targets removed before a given index.
- if (targetBlockIndex + 1 < targetBlockIndexOffset.length) {
- targetBlockIndexOffset[targetBlockIndex + 1] = 1;
- }
+ for (int removedSuccessorIndex : removedSuccessorIndices) {
+ targetBlockIndexOffset[removedSuccessorIndex] = 1;
}
-
for (int i = 1; i < targetBlockIndexOffset.length; i++) {
targetBlockIndexOffset[i] += targetBlockIndexOffset[i - 1];
}
diff --git a/src/test/java/com/android/tools/r8/ir/optimize/switches/DeadSwitchCaseWithSharedTargetTest.java b/src/test/java/com/android/tools/r8/ir/optimize/switches/DeadSwitchCaseWithSharedTargetTest.java
new file mode 100644
index 0000000..6fd4739
--- /dev/null
+++ b/src/test/java/com/android/tools/r8/ir/optimize/switches/DeadSwitchCaseWithSharedTargetTest.java
@@ -0,0 +1,82 @@
+// Copyright (c) 2021, the R8 project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.android.tools.r8.ir.optimize.switches;
+
+import com.android.tools.r8.TestBase;
+import com.android.tools.r8.TestParameters;
+import com.android.tools.r8.TestParametersCollection;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(Parameterized.class)
+public class DeadSwitchCaseWithSharedTargetTest extends TestBase {
+
+ private final TestParameters parameters;
+
+ @Parameterized.Parameters(name = "{0}")
+ public static TestParametersCollection data() {
+ return getTestParameters().withAllRuntimesAndApiLevels().build();
+ }
+
+ public DeadSwitchCaseWithSharedTargetTest(TestParameters parameters) {
+ this.parameters = parameters;
+ }
+
+ @Test
+ public void test() throws Exception {
+ testForR8(parameters.getBackend())
+ .addInnerClasses(getClass())
+ .addKeepMainRule(Main.class)
+ .addKeepRules(
+ "-assumevalues class " + Main.class.getTypeName() + " {",
+ " static int FIELD return 27..30;",
+ "}")
+ .setMinApi(parameters.getApiLevel())
+ .compile()
+ .run(parameters.getRuntime(), Main.class)
+ .assertSuccessWithOutputLines("?", "?", "O", "P", "Q", "R", "?");
+ }
+
+ static class Main {
+
+ static int FIELD;
+ static boolean alwaysTrue = System.currentTimeMillis() >= 0;
+
+ public static void main(String[] args) {
+ test(25);
+ test(26);
+ test(27);
+ test(28);
+ test(29);
+ test(30);
+ test(31);
+ }
+
+ static void test(int i) {
+ if (alwaysTrue) {
+ FIELD = i;
+ }
+ switch (FIELD) {
+ case 26:
+ case 27:
+ System.out.println("O");
+ break;
+ case 28:
+ System.out.println("P");
+ break;
+ case 29:
+ System.out.println("Q");
+ break;
+ case 30:
+ System.out.println("R");
+ break;
+ default:
+ System.out.println("?");
+ break;
+ }
+ }
+ }
+}
