In optimized code use IC calls for instance calls that have no IC data instead of deoptimizing. The…

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
===================================================================
--- runtime/vm/flow_graph_compiler_x64.cc	(revision 14798)
+++ runtime/vm/flow_graph_compiler_x64.cc	(working copy)
@@ -1046,6 +1046,27 @@
 }
 
 
+void FlowGraphCompiler::EmitOptimizedInstanceCall(
+    ExternalLabel* target_label,
+    const ICData& ic_data,
+    const Array& arguments_descriptor,
+    intptr_t argument_count,
+    intptr_t deopt_id,
+    intptr_t token_pos,
+    LocationSummary* locs) {
+  // Load top function since it may not correspond to the ICData function.
+  __ LoadObject(RDI, parsed_function().function());
+  __ LoadObject(RBX, ic_data);
+  __ LoadObject(R10, arguments_descriptor);
+  GenerateDartCall(deopt_id,
+                   token_pos,
+                   target_label,
+                   PcDescriptors::kIcCall,
+                   locs);
+  __ Drop(argument_count);
+}
+
+
 void FlowGraphCompiler::EmitInstanceCall(ExternalLabel* target_label,
                                          const ICData& ic_data,
                                          const Array& arguments_descriptor,