[TRE] Update comments. NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305636 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/TailRecursionElimination.cpp

@@ -679,7 +679,7 @@ static bool foldReturnAndProcessPred(BasicBlock *BB, ReturnInst *Ret,
 
   // If the return block contains nothing but the return and PHI's,
   // there might be an opportunity to duplicate the return in its
-  // predecessors and perform TRC there. Look for predecessors that end
+  // predecessors and perform TRE there. Look for predecessors that end
   // in unconditional branch and recursive call(s).
   SmallVector<BranchInst*, 8> UncondBranchPreds;
   for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {