CodeGen: Use MachineInstr& in TargetLowering, NFC

This is a mechanical change to make TargetLowering API take MachineInstr&
(instead of MachineInstr*), since the argument is expected to be a valid
MachineInstr.  In one case, changed a parameter from MachineInstr* to
MachineBasicBlock::iterator, since it was used as an insertion point.

As a side effect, this removes a bunch of MachineInstr* to
MachineBasicBlock::iterator implicit conversions, a necessary step
toward fixing PR26753.

llvm-svn: 274287
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.h b/llvm/lib/Target/Sparc/SparcISelLowering.h
index 0fe18b1..e0a421b 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.h
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.h
@@ -72,8 +72,8 @@
                                        unsigned Depth = 0) const override;
 
     MachineBasicBlock *
-      EmitInstrWithCustomInserter(MachineInstr *MI,
-                                  MachineBasicBlock *MBB) const override;
+    EmitInstrWithCustomInserter(MachineInstr &MI,
+                                MachineBasicBlock *MBB) const override;
 
     const char *getTargetNodeName(unsigned Opcode) const override;
 
@@ -211,11 +211,11 @@
                             SmallVectorImpl<SDValue>& Results,
                             SelectionDAG &DAG) const override;
 
-    MachineBasicBlock *expandSelectCC(MachineInstr *MI, MachineBasicBlock *BB,
+    MachineBasicBlock *expandSelectCC(MachineInstr &MI, MachineBasicBlock *BB,
                                       unsigned BROpcode) const;
-    MachineBasicBlock *emitEHSjLjSetJmp(MachineInstr *MI,
+    MachineBasicBlock *emitEHSjLjSetJmp(MachineInstr &MI,
                                         MachineBasicBlock *MBB) const;
-    MachineBasicBlock *emitEHSjLjLongJmp(MachineInstr *MI,
+    MachineBasicBlock *emitEHSjLjLongJmp(MachineInstr &MI,
                                          MachineBasicBlock *MBB) const;
   };
 } // end namespace llvm