[LoopUtils] Use llvm::find

[orivej]

Summary

Fixes this build error:

llvm/lib/Transforms/Utils/LoopUtils.cpp:679:26: error: no matching function for call to 'find'
      Loop::iterator I = find(ParentLoop->begin(), ParentLoop->end(), L);
                         ^~~~

[Whitney]

llvm/lib/Transforms/Utils/LoopUtils.cpp

716

How about change to Loop::iterator I = find(ParentLoop, L)?

720

How about change to Loop::iterator I = find(LI, L);

[orivej]

I have tried that first, but I should have dereferenced too. Done.

[orivej]

I do not have commit access, could you please commit on my behalf?

llvm/lib/Transforms/Utils/LoopUtils.cpp

if (LI) {
     for (BasicBlock *BB : blocks)
       LI->removeBlock(BB);
 
     // The last step is to update LoopInfo now that we've eliminated this loop.
     // Note: LoopInfo::erase remove the given loop and relink its subloops with
     // its parent. While removeLoop/removeChildLoop remove the given loop but
     // not relink its subloops, which is what we want.
     if (Loop *ParentLoop = L->getParentLoop()) {
-      Loop::iterator I = find(ParentLoop->begin(), ParentLoop->end(), L);
+      Loop::iterator I = find(*ParentLoop, L);
       assert(I != ParentLoop->end() && "Couldn't find loop");
       ParentLoop->removeChildLoop(I);
     } else {
-      Loop::iterator I = find(LI->begin(), LI->end(), L);
+      Loop::iterator I = find(*LI, L);
       assert(I != LI->end() && "Couldn't find loop");
       LI->removeLoop(I);
     }
     LI->destroy(L);
   }
 }
 
 /// Checks if \p L has single exit through latch block except possibly