Push safepoint registers in deferred number-to-i/u only on-demand.

src/arm/lithium-codegen-arm.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 108 matching lines @@
   bool GenerateCode();
 
   // Finish the code by setting stack height, safepoint, and bailout
   // information on it.
   void FinishCode(Handle<Code> code);
 
   // Deferred code support.
   void DoDeferredNumberTagD(LNumberTagD* instr);
 
   enum IntegerSignedness { SIGNED_INT32, UNSIGNED_INT32 };
-  void DoDeferredNumberTagI(LInstruction* instr,
-                            LOperand* value,
-                            IntegerSignedness signedness);
+  void DoDeferredNumberTagIU(LInstruction* instr,
+                             LOperand* value,
+                             LOperand* temp1,
+                             LOperand* temp2,
+                             IntegerSignedness signedness);
 
   void DoDeferredTaggedToI(LTaggedToI* instr);
   void DoDeferredMathAbsTaggedHeapNumber(LMathAbs* instr);
   void DoDeferredStackCheck(LStackCheck* instr);
   void DoDeferredStringCharCodeAt(LStringCharCodeAt* instr);
   void DoDeferredStringCharFromCode(LStringCharFromCode* instr);
   void DoDeferredAllocate(LAllocate* instr);
   void DoDeferredInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr,
                                        Label* map_check);
   void DoDeferredInstanceMigration(LCheckMaps* instr, Register object);
@@ skipping 317 matching lines @@
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_CODEGEN_ARM_H_