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

llvm/lib/CodeGen/MachineTraceMetrics.cpp

@@ -627,7 +627,7 @@ struct DataDep {
     assert(TargetRegisterInfo::isVirtualRegister(VirtReg));
     MachineRegisterInfo::def_iterator DefI = MRI->def_begin(VirtReg);
     assert(!DefI.atEnd() && "Register has no defs");
-    DefMI = &*DefI;
+    DefMI = DefI->getParent();
     DefOp = DefI.getOperandNo();
     assert((++DefI).atEnd() && "Register has multiple defs");
   }