A64: Implement Peek/PokePair

src/a64/code-stubs-a64.cc

Index: src/a64/code-stubs-a64.cc
diff --git a/src/a64/code-stubs-a64.cc b/src/a64/code-stubs-a64.cc
index 401d5a8d4eae1c2a4302f1dcb6367c1e6bd80857..594860ce8e87e6e6d36562da1204410238e4c3ab 100644
--- a/src/a64/code-stubs-a64.cc
+++ b/src/a64/code-stubs-a64.cc
@@ -6357,9 +6357,7 @@ void StoreArrayLiteralElementStub::Generate(MacroAssembler* masm) {
   Register array = x1;
   Register array_map = x2;
   Register array_index_smi = x4;
-  // TODO(jbramley): Implement PeekPair and use it here.
-  __ Peek(array, 1 * kPointerSize);
-  __ Peek(array_index_smi, 0 * kPointerSize);
+  __ PeekPair(array_index_smi, array, 0);
   __ Ldr(array_map, FieldMemOperand(array, JSObject::kMapOffset));
 
   Label double_elements, smi_element, fast_elements, slow_elements;