CodeGen: Use MachineInstr& in AntiDepBreaker API, NFC

Take parameters as MachineInstr& instead of MachineInstr* in
AntiDepBreaker API, since these are required to be non-null.  No
functionality change intended.  Looking toward PR26753.

llvm-svn: 262145
diff --git a/llvm/lib/CodeGen/PostRASchedulerList.cpp b/llvm/lib/CodeGen/PostRASchedulerList.cpp
index b95dffd..06a88bf 100644
--- a/llvm/lib/CodeGen/PostRASchedulerList.cpp
+++ b/llvm/lib/CodeGen/PostRASchedulerList.cpp
@@ -169,7 +169,7 @@
     /// Observe - Update liveness information to account for the current
     /// instruction, which will not be scheduled.
     ///
-    void Observe(MachineInstr *MI, unsigned Count);
+    void Observe(MachineInstr &MI, unsigned Count);
 
     /// finishBlock - Clean up register live-range state.
     ///
@@ -335,7 +335,7 @@
         Scheduler.EmitSchedule();
         Current = MI;
         CurrentCount = Count;
-        Scheduler.Observe(MI, CurrentCount);
+        Scheduler.Observe(*MI, CurrentCount);
       }
       I = MI;
       if (MI->isBundle())
@@ -414,7 +414,7 @@
 /// Observe - Update liveness information to account for the current
 /// instruction, which will not be scheduled.
 ///
-void SchedulePostRATDList::Observe(MachineInstr *MI, unsigned Count) {
+void SchedulePostRATDList::Observe(MachineInstr &MI, unsigned Count) {
   if (AntiDepBreak)
     AntiDepBreak->Observe(MI, Count, EndIndex);
 }