Consistently make the bounds check for AccessArgumentsAt explicit.

src/arm/lithium-codegen-arm.cc

 // 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 2886 matching lines @@
   __ ldr(to_reg, FieldMemOperand(from_reg,
                                  ExternalArray::kExternalPointerOffset));
 }
 
 
 void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
   Register arguments = ToRegister(instr->arguments());
   Register length = ToRegister(instr->length());
   Register index = ToRegister(instr->index());
   Register result = ToRegister(instr->result());
-
-  // Bailout index is not a valid argument index. Use unsigned check to get
-  // negative check for free.
-  __ sub(length, length, index, SetCC);
-  DeoptimizeIf(ls, instr->environment());
-
   // There are two words between the frame pointer and the last argument.
   // Subtracting from length accounts for one of them add one more.
+  __ sub(length, length, index);
   __ add(length, length, Operand(1));
   __ ldr(result, MemOperand(arguments, length, LSL, kPointerSizeLog2));
 }
 
 
 void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
   Register elements = ToRegister(instr->elements());
   Register result = ToRegister(instr->result());
   Register scratch = scratch0();
   Register store_base = scratch;
@@ skipping 2753 matching lines @@
   __ sub(scratch, result, Operand(index, LSL, kPointerSizeLog2 - kSmiTagSize));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal