PPC: VectorICs: use a vector slot to aid in array literal processing.

Port f2f46aff

Original commit message:
    The lack of a vector slot for the keyed store operation in filling in
    non-constant array literal properties led to undesirable contortions in
    compilers downwind of full-codegen. The use of a single slot to initialize all
    the array elements is sufficient.

R=mvstanton@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, dstence@us.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1390353006

Cr-Commit-Position: refs/heads/master@{#31261}

src/full-codegen/ppc/full-codegen-ppc.cc

@@ -1715,7 +1715,6 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
 void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   Comment cmnt(masm_, "[ ArrayLiteral");
 
-  expr->BuildConstantElements(isolate());
   Handle<FixedArray> constant_elements = expr->constant_elements();
   bool has_fast_elements =
       IsFastObjectElementsKind(expr->constant_elements_kind());
@@ -1764,7 +1763,16 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
     }
     VisitForAccumulatorValue(subexpr);
 
-    if (has_fast_elements) {
+    if (FLAG_vector_stores) {
+      __ LoadSmiLiteral(StoreDescriptor::NameRegister(),
+                        Smi::FromInt(array_index));
+      __ LoadP(StoreDescriptor::ReceiverRegister(),
+               MemOperand(sp, kPointerSize));
+      EmitLoadStoreICSlot(expr->LiteralFeedbackSlot());
+      Handle<Code> ic =
+          CodeFactory::KeyedStoreIC(isolate(), language_mode()).code();
+      CallIC(ic);
+    } else if (has_fast_elements) {
       int offset = FixedArray::kHeaderSize + (array_index * kPointerSize);
       __ LoadP(r8, MemOperand(sp, kPointerSize));  // Copy of array literal.
       __ LoadP(r4, FieldMemOperand(r8, JSObject::kElementsOffset));