Consistently make the bounds check for AccessArgumentsAt explicit.

src/mips/lithium-codegen-mips.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
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 //     * Redistributions in binary form must reproduce the above
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@@ skipping 2594 matching lines @@
   __ lw(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.
-
-  // TODO(plind): Shoud be optimized to do the sub before the DeoptimizeIf(),
-  // as they do in Arm. It will save us an instruction.
-  DeoptimizeIf(ls, instr->environment(), length, Operand(index));
-
   // There are two words between the frame pointer and the last argument.
   // Subtracting from length accounts for one of them, add one more.
   __ subu(length, length, index);
   __ Addu(length, length, Operand(1));
   __ sll(length, length, kPointerSizeLog2);
   __ Addu(at, arguments, Operand(length));
   __ lw(result, MemOperand(at, 0));
 }
 
 
@@ skipping 2815 matching lines @@
   __ Subu(scratch, result, scratch);
   __ lw(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal