Recognize and optimize a.runtimeType == b.runtimeType pattern.

runtime/vm/assembler_arm.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_ASSEMBLER_ARM_H_
 #define VM_ASSEMBLER_ARM_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_arm.h directly; use assembler.h instead.
 #endif
@@ skipping 682 matching lines @@
 
   // Add signed immediate value to rd. May clobber IP.
   void AddImmediate(Register rd, int32_t value, Condition cond = AL);
   void AddImmediate(Register rd, Register rn, int32_t value,
                     Condition cond = AL);
   void AddImmediateSetFlags(Register rd, Register rn, int32_t value,
                             Condition cond = AL);
   void SubImmediateSetFlags(Register rd, Register rn, int32_t value,
                             Condition cond = AL);
   void AndImmediate(Register rd, Register rs, int32_t imm, Condition cond = AL);
+  void SubImmediate(Register rd, Register rn, int32_t imm, Condition cond = AL);
 
   // Test rn and immediate. May clobber IP.
   void TestImmediate(Register rn, int32_t imm, Condition cond = AL);
 
   // Compare rn with signed immediate value. May clobber IP.
   void CompareImmediate(Register rn, int32_t value, Condition cond = AL);
 
 
   // Signed integer division of left by right. Checks to see if integer
   // division is supported. If not, uses the FPU for division with
@@ skipping 459 matching lines @@
                                   Register value,
                                   Label* no_update);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_ARM_H_