Implement optional turbofan UnalignedLoad and UnalignedStore operators

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index 91900be25c30dabec502028de1401680631509ae..ec78a4daf6d2b5406c84b93985f337b9f1f12939 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -705,6 +705,7 @@ void InstructionSelector::VisitBlock(BasicBlock* block) {
   int effect_level = 0;
   for (Node* const node : *block) {
     if (node->opcode() == IrOpcode::kStore ||
+        node->opcode() == IrOpcode::kUnalignedStore ||
         node->opcode() == IrOpcode::kCheckedStore ||
         node->opcode() == IrOpcode::kCall) {
       ++effect_level;
@@ -1142,6 +1143,14 @@ void InstructionSelector::VisitNode(Node* node) {
       return VisitLoadFramePointer(node);
     case IrOpcode::kLoadParentFramePointer:
       return VisitLoadParentFramePointer(node);
+    case IrOpcode::kUnalignedLoad: {
+      UnalignedLoadRepresentation type =
+          UnalignedLoadRepresentationOf(node->op());
+      MarkAsRepresentation(type.representation(), node);
+      return VisitUnalignedLoad(node);
+    }
+    case IrOpcode::kUnalignedStore:
+      return VisitUnalignedStore(node);
     case IrOpcode::kCheckedLoad: {
       MachineRepresentation rep =
           CheckedLoadRepresentationOf(node->op()).representation();