Merge "Don't consider debug-value uses as actual uses."

3 files changed, 23 insertions, 26 deletions

diff --git a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
index 631f8b2a9..eb0aa77f5 100644
--- a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
+++ b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
@@ -1808,7 +1808,7 @@ public class LinearScanRegisterAllocator implements RegisterAllocator {
               addLiveRange(use, block, number);
             }
             LiveIntervals useIntervals = use.getLiveIntervals();
-            useIntervals.addUse(new LiveIntervalsUse(number, Constants.U16BIT_MAX));
+            useIntervals.addUse(new LiveIntervalsUse(number, Constants.U16BIT_MAX, true));
           }
           Value use = instruction.getPreviousLocalValue();
           if (use != null) {
@@ -1818,7 +1818,7 @@ public class LinearScanRegisterAllocator implements RegisterAllocator {
               addLiveRange(use, block, number);
             }
             LiveIntervals useIntervals = use.getLiveIntervals();
-            useIntervals.addUse(new LiveIntervalsUse(number, Constants.U16BIT_MAX));
+            useIntervals.addUse(new LiveIntervalsUse(number, Constants.U16BIT_MAX, true));
           }
         }
       }
@@ -1850,27 +1850,14 @@ public class LinearScanRegisterAllocator implements RegisterAllocator {
       Value previous = null;
       for (int i = 0; i < arguments.size(); i++) {
         Value argument = arguments.get(i);
-        Value newArgument = argument;
-        // In debug mode, we have debug instructions that are also moves. Do not generate another
-        // move if there already is a move instruction that we can use. We generate moves if:
-        //
-        // 1. the argument is not defined by a move,
-        //
-        // 2. the argument is already linked or would cause a cycle if linked, or
-        //
-        // 3. the argument has a register constraint (the argument moves are there to make the
-        //    input value to a ranged invoke unconstrained.)
-        if (argument.definition == null ||
-            !argument.definition.isMove() ||
-            argument.isLinked() ||
-            argument == previous ||
-            argument.hasRegisterConstraint()) {
-          newArgument = createValue(argument.outType());
-          Move move = new Move(newArgument, argument);
-          move.setBlock(invoke.getBlock());
-          replaceArgument(invoke, i, newArgument);
-          insertAt.add(move);
-        }
+        // TODO(ager): Conditionally create a new argument if it is not already a move.
+        // Reverted optimization from CL: https://r8-review.googlesource.com/c/1985/
+        // Not considering debug-uses causes a unlinked/non-consecutive register in some cases.
+        Value newArgument = createValue(argument.outType());
+        Move move = new Move(newArgument, argument);
+        move.setBlock(invoke.getBlock());
+        replaceArgument(invoke, i, newArgument);
+        insertAt.add(move);
         if (previous != null) {
           previous.linkTo(newArgument);
         }
diff --git a/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervals.java b/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervals.java
index 06b33f473..9c28724a7 100644
--- a/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervals.java
+++ b/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervals.java
@@ -319,7 +319,7 @@ public class LiveIntervals {
 
   public int firstUseAfter(int unhandledStart) {
     for (LiveIntervalsUse use : uses) {
-      if (use.getPosition() >= unhandledStart) {
+      if (use.getPosition() >= unhandledStart && !use.isDebugUse()) {
         return use.getPosition();
       }
     }
diff --git a/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervalsUse.java b/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervalsUse.java
index a60213453..edf876ded 100644
--- a/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervalsUse.java
+++ b/src/main/java/com/android/tools/r8/ir/regalloc/LiveIntervalsUse.java
@@ -6,12 +6,18 @@ package com.android.tools.r8.ir.regalloc;
 import static com.android.tools.r8.dex.Constants.U16BIT_MAX;
 
 public class LiveIntervalsUse implements Comparable<LiveIntervalsUse> {
-  private int position;
-  private int limit;
+  private final int position;
+  private final int limit;
+  private final boolean debugUse;
 
   public LiveIntervalsUse(int position, int limit) {
+    this(position, limit, false);
+  }
+
+  public LiveIntervalsUse(int position, int limit, boolean debugUse) {
     this.position = position;
     this.limit = limit;
+    this.debugUse = debugUse;
   }
 
   public int getPosition() {
@@ -47,4 +53,8 @@ public class LiveIntervalsUse implements Comparable<LiveIntervalsUse> {
   public boolean hasConstraint() {
     return limit < U16BIT_MAX;
   }
+
+  public boolean isDebugUse() {
+    return debugUse;
+  }
 }