VM: Array bounds checks that don't deoptimize for precompiled code.

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 889 matching lines @@
   // Untag the value in the register assuming it is a smi.
   // Untagging shifts tag bit into the carry flag - if carry is clear
   // assumption was correct. In this case jump to the is_smi label.
   // Otherwise fall-through.
   void SmiUntag(Register dst, Register src, Label* is_smi) {
     ASSERT(kSmiTagSize == 1);
     Asrs(dst, src, Operand(kSmiTagSize));
     b(is_smi, CC);
   }
 
+  void BranchIfNotSmi(Register reg, Label* label) {
+    tst(reg, Operand(kSmiTagMask));
+    b(label, NE);
+  }
+
   void CheckCodePointer();
 
   // Function frame setup and tear down.
   void EnterFrame(RegList regs, intptr_t frame_space);
   void LeaveFrame(RegList regs);
   void Ret();
   void ReserveAlignedFrameSpace(intptr_t frame_space);
 
   // Create a frame for calling into runtime that preserves all volatile
   // registers.  Frame's SP is guaranteed to be correctly aligned and
@@ skipping 242 matching lines @@
                                   Register value,
                                   Label* no_update);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_ARM_H_