Add pass that expands pseudo instructions into target instructions after register allocation. Define pseudos that get expanded into mtc1 or mfc1 instructions.

llvm-svn: 129594
diff --git a/llvm/lib/Target/Mips/MipsTargetMachine.h b/llvm/lib/Target/Mips/MipsTargetMachine.h
index 43ab798..badb652 100644
--- a/llvm/lib/Target/Mips/MipsTargetMachine.h
+++ b/llvm/lib/Target/Mips/MipsTargetMachine.h
@@ -63,6 +63,7 @@
                                  CodeGenOpt::Level OptLevel);
     virtual bool addPreEmitPass(PassManagerBase &PM,
                                 CodeGenOpt::Level OptLevel);
+    virtual bool addPostRegAlloc(PassManagerBase &, CodeGenOpt::Level);
   };
 
 /// MipselTargetMachine - Mipsel target machine.