Fix undefined value error from shorten live ranges

Bug: b/241636314
Change-Id: I1af99a055108fb6454751169fc6989537d67591d

src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java

diff --git a/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java b/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java
index 85802c1..36b96dc 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java
@@ -2045,23 +2045,6 @@
       // Locate the closest dominator block for all user blocks.
       DominatorTree dominatorTree = dominatorTreeMemoization.computeIfAbsent();
       BasicBlock dominator = dominatorTree.closestDominator(userBlocks);
-      // If the closest dominator block is a block that uses the constant for a phi the constant
-      // needs to go in the immediate dominator block so that it is available for phi moves.
-      for (Phi phi : instruction.outValue().uniquePhiUsers()) {
-        if (phi.getBlock() == dominator) {
-          if (instruction.outValue().numberOfAllUsers() == 1 &&
-              phi.usesValueOneTime(instruction.outValue())) {
-            // Out value is used only one time, move the constant directly to the corresponding
-            // branch rather than into the dominator to avoid to generate a const on paths which
-            // does not required it.
-            int predIndex = phi.getOperands().indexOf(instruction.outValue());
-            dominator = dominator.getPredecessors().get(predIndex);
-          } else {
-            dominator = dominatorTree.immediateDominator(dominator);
-          }
-          break;
-        }
-      }
 
       if (instruction.instructionTypeCanThrow()) {
         if (block.hasCatchHandlers() || dominator.hasCatchHandlers()) {

src/test/java/com/android/tools/r8/ir/optimize/ShortenLiveRangesOfInstanceGetWithPhiUserRegressionTest.java

diff --git a/src/test/java/com/android/tools/r8/ir/optimize/ShortenLiveRangesOfInstanceGetWithPhiUserRegressionTest.java b/src/test/java/com/android/tools/r8/ir/optimize/ShortenLiveRangesOfInstanceGetWithPhiUserRegressionTest.java
index be5cb83..20b3e58 100644
--- a/src/test/java/com/android/tools/r8/ir/optimize/ShortenLiveRangesOfInstanceGetWithPhiUserRegressionTest.java
+++ b/src/test/java/com/android/tools/r8/ir/optimize/ShortenLiveRangesOfInstanceGetWithPhiUserRegressionTest.java
@@ -7,7 +7,6 @@
 import com.android.tools.r8.TestBase;
 import com.android.tools.r8.TestParameters;
 import com.android.tools.r8.TestParametersCollection;
-import com.android.tools.r8.utils.codeinspector.AssertUtils;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
@@ -28,15 +27,12 @@
 
   @Test
   public void test() throws Exception {
-    AssertUtils.assertFailsCompilationIf(
-        parameters.isDexRuntime(),
-        () ->
-            testForR8(parameters.getBackend())
-                .addInnerClasses(getClass())
-                .addKeepMainRule(Main.class)
-                .setMinApi(parameters.getApiLevel())
-                .run(parameters.getRuntime(), Main.class)
-                .assertSuccessWithOutputLines("0", "1", "2"));
+    testForR8(parameters.getBackend())
+        .addInnerClasses(getClass())
+        .addKeepMainRule(Main.class)
+        .setMinApi(parameters.getApiLevel())
+        .run(parameters.getRuntime(), Main.class)
+        .assertSuccessWithOutputLines("0", "1", "2");
   }
 
   static class Main {