Switch all register list clients to the new MC*Iterator interface.

No functional change intended.

Sorry for the churn. The iterator classes are supposed to help avoid
giant commits like this one in the future. The TableGen-produced
register lists are getting quite large, and it may be necessary to
change the table representation.

This makes it possible to do so without changing all clients (again).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157854 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineInstrBundle.cpp b/lib/CodeGen/MachineInstrBundle.cpp
index 73489a7..b7de7bf 100644
--- a/lib/CodeGen/MachineInstrBundle.cpp
+++ b/lib/CodeGen/MachineInstrBundle.cpp
@@ -169,8 +169,8 @@
       }
 
       if (!MO.isDead()) {
-        for (const uint16_t *SubRegs = TRI->getSubRegisters(Reg);
-             unsigned SubReg = *SubRegs; ++SubRegs) {
+        for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
+          unsigned SubReg = *SubRegs;
           if (LocalDefSet.insert(SubReg))
             LocalDefs.push_back(SubReg);
         }