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/CriticalAntiDepBreaker.h b/llvm/lib/CodeGen/CriticalAntiDepBreaker.h
index 10b8739..ac0dac6 100644
--- a/llvm/lib/CodeGen/CriticalAntiDepBreaker.h
+++ b/llvm/lib/CodeGen/CriticalAntiDepBreaker.h
@@ -84,15 +84,15 @@
 
     /// 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,
                  unsigned InsertPosIndex) override;
 
     /// Finish anti-dep breaking for a basic block.
     void FinishBlock() override;
 
   private:
-    void PrescanInstruction(MachineInstr *MI);
-    void ScanInstruction(MachineInstr *MI, unsigned Count);
+    void PrescanInstruction(MachineInstr &MI);
+    void ScanInstruction(MachineInstr &MI, unsigned Count);
     bool isNewRegClobberedByRefs(RegRefIter RegRefBegin,
                                  RegRefIter RegRefEnd,
                                  unsigned NewReg);