Subzero: Fix ODR errors in the g++ build.

src/IceInstMIPS32.h

 //===- subzero/src/IceInstMIPS32.h - MIPS32 machine instrs --*- C++ -*-===    //
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 496 matching lines @@
 private:
   InstMIPS32Mov(Cfg *Func, Variable *Dest, Operand *Src);
 
   void emitMultiDestSingleSource(const Cfg *Func) const;
   void emitSingleDestMultiSource(const Cfg *Func) const;
   void emitSingleDestSingleSource(const Cfg *Func) const;
 
   Variable *DestHi = nullptr;
 };
 
+// Declare partial template specializations of emit() methods that already have
+// default implementations. Without this, there is the possibility of ODR
+// violations and link errors.
+
+template <> void InstMIPS32Mflo::emit(const Cfg *Func) const;
+template <> void InstMIPS32Mfhi::emit(const Cfg *Func) const;
+template <> void InstMIPS32Mtlo::emit(const Cfg *Func) const;
+template <> void InstMIPS32Mthi::emit(const Cfg *Func) const;
+template <> void InstMIPS32Mult::emit(const Cfg *Func) const;
+template <> void InstMIPS32Multu::emit(const Cfg *Func) const;
+
 } // end of namespace MIPS32
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINSTMIPS32_H