[PM] Now that LoopInfo isn't in the Pass type hierarchy, it is much

cleaner to derive from the generic base.

Thise removes a ton of boiler plate code and somewhat strange and
pointless indirections. It also remove a bunch of the previously needed
friend declarations. To fully remove these, I also lifted the verify
logic into the generic LoopInfoBase, which seems good anyways -- it is
generic and useful logic even for the machine side.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226385 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/LoopSimplify.cpp

@@ -460,7 +460,7 @@ static BasicBlock *insertUniqueBackedgeBlock(Loop *L, BasicBlock *Preheader,
 
   // Update Loop Information - we know that this block is now in the current
   // loop and all parent loops.
-  L->addBasicBlockToLoop(BEBlock, LI->getBase());
+  L->addBasicBlockToLoop(BEBlock, *LI);
 
   // Update dominator information
   DT->splitBlock(BEBlock);