Desugar bitwise negation into XOR and kill all UnaryOp stuff.

src/mips/lithium-codegen-mips.h

Index: src/mips/lithium-codegen-mips.h
diff --git a/src/mips/lithium-codegen-mips.h b/src/mips/lithium-codegen-mips.h
index cc3873d8454b5154169aaf7f98a48fdfb9d98249..670c4cc87a7927d8c04fec47c36e14c059e93123 100644
--- a/src/mips/lithium-codegen-mips.h
+++ b/src/mips/lithium-codegen-mips.h
@@ -114,7 +114,7 @@ class LCodeGen BASE_EMBEDDED {
   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;