[turbofan] Set elements kind to holey if constructing array of possibly non-zero length.

src/compiler/js-create-lowering.cc

Index: src/compiler/js-create-lowering.cc
diff --git a/src/compiler/js-create-lowering.cc b/src/compiler/js-create-lowering.cc
index fc77138fc19f2131ba5cb8eadc7672a9cb3a5c2a..0f829d48aefad7d38583813afe60eb108ce7396b 100644
--- a/src/compiler/js-create-lowering.cc
+++ b/src/compiler/js-create-lowering.cc
@@ -473,6 +473,9 @@ Reduction JSCreateLowering::ReduceNewArray(Node* node, Node* length,
   PretenureFlag pretenure = site->GetPretenureMode();
   ElementsKind elements_kind = site->GetElementsKind();
   DCHECK(IsFastElementsKind(elements_kind));
+  if (NodeProperties::GetType(length)->Max() > 0) {

[Jarin, 2016/07/06 04:39:59]

Not sure whether we should thread through the type cache just to be able to say
!GetType(length)->Is(cache_.kSingletonZero). WDYT?

+    elements_kind = GetHoleyElementsKind(elements_kind);
+  }
   dependencies()->AssumeTenuringDecision(site);
   dependencies()->AssumeTransitionStable(site);