Move REG_SEQUENCE removal to 2addr pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103109 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineInstr.h

@@ -223,6 +223,9 @@ public:
   bool isSubregToReg() const {
     return getOpcode() == TargetOpcode::SUBREG_TO_REG;
   }
+  bool isRegSequence() const {
+    return getOpcode() == TargetOpcode::REG_SEQUENCE;
+  }
   
   /// readsRegister - Return true if the MachineInstr reads the specified
   /// register. If TargetRegisterInfo is passed, then it also checks if there