a previous patch completely disabled trivial unswitching, this fixees it.

Thanks to nate for pointing this out :)

llvm-svn: 26280

llvm/lib/Transforms/Scalar/LoopUnswitch.cpp

@@ -168,7 +168,6 @@ static bool isTrivialLoopExitBlockHelper(Loop *L, BasicBlock *BB,
 static BasicBlock *isTrivialLoopExitBlock(Loop *L, BasicBlock *BB) {
   std::set<BasicBlock*> Visited;
   Visited.insert(L->getHeader());  // Branches to header are ok.
-  Visited.insert(BB);              // Don't revisit BB after we do.
   BasicBlock *ExitBB = 0;
   if (isTrivialLoopExitBlockHelper(L, BB, ExitBB, Visited))
     return ExitBB;