Replace all accesses to User::OperandList with getter and setter methods. NFC.

We don't want anyone to access OperandList directly as its going to be removed
and computed instead.  This uses getter's and setter's instead in which we
can later change the underlying implementation of OperandList.

Reviewed by Duncan Exon Smith.

llvm-svn: 239620
diff --git a/llvm/lib/IR/User.cpp b/llvm/lib/IR/User.cpp
index d659352..0cba526 100644
--- a/llvm/lib/IR/User.cpp
+++ b/llvm/lib/IR/User.cpp
@@ -49,7 +49,7 @@
   Use *Begin = static_cast<Use*>(::operator new(size));
   Use *End = Begin + N;
   (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
-  OperandList = Use::initTags(Begin, End);
+  setOperandList(Use::initTags(Begin, End));
   // Tag this operand list as being a hung off.
   HasHungOffUses = true;
 }
@@ -63,9 +63,9 @@
   // space to copy the old uses in to the new space.
   assert(NewNumUses > OldNumUses && "realloc must grow num uses");
 
-  Use *OldOps = OperandList;
+  Use *OldOps = getOperandList();
   allocHungoffUses(NewNumUses, IsPhi);
-  Use *NewOps = OperandList;
+  Use *NewOps = getOperandList();
 
   // Now copy from the old operands list to the new one.
   std::copy(OldOps, OldOps + OldNumUses, NewOps);
@@ -90,7 +90,7 @@
   Use *Start = static_cast<Use*>(Storage);
   Use *End = Start + Us;
   User *Obj = reinterpret_cast<User*>(End);
-  Obj->OperandList = Start;
+  Obj->setOperandList(Start);
   Obj->HasHungOffUses = false;
   Obj->NumOperands = Us;
   Use::initTags(Start, End);