Desugar bitwise negation into XOR and kill all UnaryOp stuff.

src/mips/lithium-codegen-mips.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 96 matching lines @@
   // LOperand is loaded into scratch, unless already a register.
   Register EmitLoadRegister(LOperand* op, Register scratch);
 
   // LOperand must be a double register.
   DoubleRegister ToDoubleRegister(LOperand* op) const;
 
   // LOperand is loaded into dbl_scratch, unless already a double register.
   DoubleRegister EmitLoadDoubleRegister(LOperand* op,
                                         FloatRegister flt_scratch,
                                         DoubleRegister dbl_scratch);
-  int ToRepresentation(LConstantOperand* op, const Representation& r) const;
+  int32_t ToRepresentation(LConstantOperand* op, const Representation& r) const;
   int32_t ToInteger32(LConstantOperand* op) const;
   Smi* ToSmi(LConstantOperand* op) const;
   double ToDouble(LConstantOperand* op) const;
   Operand ToOperand(LOperand* op);
   MemOperand ToMemOperand(LOperand* op) const;
   // Returns a MemOperand pointing to the high word of a DoubleStackSlot.
   MemOperand ToHighMemOperand(LOperand* op) const;
 
   bool IsInteger32(LConstantOperand* op) const;
   bool IsSmi(LConstantOperand* op) const;
@@ skipping 381 matching lines @@
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_MIPS_LITHIUM_CODEGEN_MIPS_H_