ARM64: Regenerate instead of spilling and restoring cheap lithium instructions.

src/lithium.cc

Index: src/lithium.cc
diff --git a/src/lithium.cc b/src/lithium.cc
index 1a97df67cdcf097e1e110612c1bbfcaa90ec41d2..665ef4bb8736ffa47986ffd9451f1c30cc89cd75 100644
--- a/src/lithium.cc
+++ b/src/lithium.cc
@@ -134,6 +134,17 @@ void LOperand::TearDownCaches() {
 }
 
 
+bool LMoveOperands::UsesRegeneration() const {
+  bool prefer_regen =
+      (source_->parent_linstr() == destination_->parent_linstr()) &&
+      (destination_->parent_linstr() != NULL) &&
+      destination_->parent_linstr()->PreferRegenerateToSpill();
+  bool one_is_mem = source_->IsInMemory() || destination_->IsInMemory();
+  bool one_is_reg = source_->IsInRegister() || destination_->IsInRegister();
+  return prefer_regen && one_is_mem && one_is_reg;
+}
+
+
 bool LParallelMove::IsRedundant() const {
   for (int i = 0; i < move_operands_.length(); ++i) {
     if (!move_operands_[i].IsRedundant()) return false;