Pack MachineOperand bitfields better.

Previously, 4 bits were unused.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171814 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 7bb8ab2..29d8866 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -143,7 +143,7 @@
   // Change this to a register and set the reg#.
   OpKind = MO_Register;
   SmallContents.RegNo = Reg;
-  SubReg = 0;
+  SubReg_TargetFlags = 0;
   IsDef = isDef;
   IsImp = isImp;
   IsKill = isKill;