Phase 2 of the great MachineRegisterInfo cleanup.  This time, we're changing
operator* on the by-operand iterators to return a MachineOperand& rather than
a MachineInstr&.  At this point they almost behave like normal iterators!

Again, this requires making some existing loops more verbose, but should pave
the way for the big range-based for-loop cleanups in the future.

llvm-svn: 203865
diff --git a/llvm/lib/CodeGen/VirtRegMap.cpp b/llvm/lib/CodeGen/VirtRegMap.cpp
index f87c8b0..54bc6f8 100644
--- a/llvm/lib/CodeGen/VirtRegMap.cpp
+++ b/llvm/lib/CodeGen/VirtRegMap.cpp
@@ -418,9 +418,9 @@
       // Check if this register has a use that will impact the rest of the
       // code. Uses in debug and noreturn instructions do not impact the
       // generated code.
-      for (MachineRegisterInfo::reg_nodbg_iterator It =
-             MRI->reg_nodbg_begin(Reg),
-             EndIt = MRI->reg_nodbg_end(); It != EndIt; ++It) {
+      for (MachineRegisterInfo::reg_instr_nodbg_iterator It =
+             MRI->reg_instr_nodbg_begin(Reg),
+             EndIt = MRI->reg_instr_nodbg_end(); It != EndIt; ++It) {
         if (!NoReturnInsts.count(&(*It))) {
           MRI->setPhysRegUsed(Reg);
           break;