commit 3726e35942658a60e9e9549dc95d62590c9eade7
author Christoffer Quist Adamsen <christofferqa@google.com> Thu May 24 07:29:03 2018 +0000
committer Gerrit Code Review <noreply-gerritcodereview@google.com> Thu May 24 07:29:03 2018 +0000
tree 42b65fb9bc1c040b063f2e16469e4e69d335c691
parent 48a131a77c112e3e6f26ec0c1497ed7141cba0b8
parent f0f3160d8e5ba8736ad1006c2a802b2ac4ba4f17

Merge "Update unsplitting of arguments"

src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java

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 d02caf9..bb27c08 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
@@ -632,13 +632,21 @@
       LiveIntervals intervals = current.getLiveIntervals();
       assert intervals.getRegisterLimit() == Constants.U16BIT_MAX;
       boolean canUseArgumentRegister = true;
+      boolean couldUseArgumentRegister = true;
       for (LiveIntervals child : intervals.getSplitChildren()) {
-        if (child.getRegisterLimit() < highestUsedRegister()) {
-          canUseArgumentRegister = false;
-          break;
+        int registerConstraint = child.getRegisterLimit();
+        if (registerConstraint < Constants.U16BIT_MAX) {
+          couldUseArgumentRegister = false;
+
+          if (registerConstraint < highestUsedRegister()) {
+            canUseArgumentRegister = false;
+            break;
+          }
         }
       }
-      if (canUseArgumentRegister) {
+      if (canUseArgumentRegister && !couldUseArgumentRegister) {
+        // Only return true if there is a constrained use where it turns out that we can use the
+        // original argument register. This way we will not unnecessarily redo move insertion.
         argumentRegisterUnsplit = true;
         for (LiveIntervals child : intervals.getSplitChildren()) {
           child.clearRegisterAssignment();