Generate some intrinsics using our IR.

runtime/vm/flow_graph_compiler.h

Index: runtime/vm/flow_graph_compiler.h
===================================================================
--- runtime/vm/flow_graph_compiler.h	(revision 39909)
+++ runtime/vm/flow_graph_compiler.h	(working copy)
@@ -273,7 +273,7 @@
 
   // Accessors.
   Assembler* assembler() const { return assembler_; }
-  const ParsedFunction& parsed_function() const { return parsed_function_; }
+  ParsedFunction& parsed_function() const { return parsed_function_; }
   const GrowableArray<BlockEntryInstr*>& block_order() const {
     return block_order_;
   }
@@ -292,6 +292,10 @@
   bool CanOSRFunction() const;
   bool is_optimizing() const { return is_optimizing_; }
 
+  void EnterIntrinsicMode();
+  void ExitIntrinsicMode();
+  bool intrinsic_mode() const { return intrinsic_mode_; }
+
   bool ForceSlowPathForStackOverflow() const;
 
   const GrowableArray<BlockInfo*>& block_info() const { return block_info_; }
@@ -601,7 +605,7 @@
 
   Isolate* isolate_;
   Assembler* assembler_;
-  const ParsedFunction& parsed_function_;
+  ParsedFunction& parsed_function_;
   const FlowGraph& flow_graph_;
   const GrowableArray<BlockEntryInstr*>& block_order_;
 
@@ -620,6 +624,9 @@
   const bool is_optimizing_;
   // Set to true if optimized code has IC calls.
   bool may_reoptimize_;
+  // True while emitting intrinsic code.
+  bool intrinsic_mode_;
+  Label intrinsic_deopt_label_;
 
   const Class& double_class_;
   const Class& mint_class_;