Improve Array.shift() performance for small arrays.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index f5c5c32f406044898596a28102d61b0a61749f0e..feb8b6b4809f795b43e5a4d8cab47ad3acc3a6d4 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -817,6 +817,7 @@ bool HInstruction::CanDeoptimize() {
     case HValue::kArgumentsElements:
     case HValue::kArgumentsLength:
     case HValue::kArgumentsObject:
+    case HValue::kArrayShift:
     case HValue::kBlockEntry:
     case HValue::kBoundsCheckBaseIndexInformation:
     case HValue::kCallFunction:
@@ -3637,6 +3638,12 @@ void HTransitionElementsKind::PrintDataTo(StringStream* stream) {
 }
 
 
+void HArrayShift::PrintDataTo(StringStream* stream) {
+  object()->PrintNameTo(stream);
+  stream->Add(" [%s]", ElementsAccessor::ForKind(kind())->name());
+}
+
+
 void HLoadGlobalCell::PrintDataTo(StringStream* stream) {
   stream->Add("[%p]", *cell().handle());
   if (!details_.IsDontDelete()) stream->Add(" (deleteable)");