Detect simple tail calls

src/compiler/js-generic-lowering.cc

Index: src/compiler/js-generic-lowering.cc
diff --git a/src/compiler/js-generic-lowering.cc b/src/compiler/js-generic-lowering.cc
index 3ebb6bc261fbec929fd2521e820a8779efb6af45..8c5c9b98d67954ecfd84f181b95339ba8952a4f7 100644
--- a/src/compiler/js-generic-lowering.cc
+++ b/src/compiler/js-generic-lowering.cc
@@ -491,8 +491,10 @@ bool JSGenericLowering::TryLowerDirectJSCall(Node* node) {
     context = jsgraph()->HeapConstant(Handle<Context>(function->context()));
   }
   node->ReplaceInput(index, context);
-  CallDescriptor* desc = Linkage::GetJSCallDescriptor(
-      zone(), false, 1 + arg_count, FlagsForNode(node));
+  CallDescriptor::Flags flags = FlagsForNode(node);
+  if (is_strict(p.language_mode())) flags |= CallDescriptor::kSupportsTailCalls;
+  CallDescriptor* desc =
+      Linkage::GetJSCallDescriptor(zone(), false, 1 + arg_count, flags);
   node->set_op(common()->Call(desc));
   return true;
 }