[LV] Don't add blocks to loop in GeneratedRTChecks (NFC).

Blocks will get added to parent loops as needed during VPlan execution.

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -2082,9 +2082,6 @@ class GeneratedRTChecks {
 
     auto *Pred = LoopVectorPreHeader->getSinglePredecessor();
     BranchInst::Create(LoopVectorPreHeader, SCEVCheckBlock);
-    // Create new preheader for vector loop.
-    if (OuterLoop)
-      OuterLoop->addBasicBlockToLoop(SCEVCheckBlock, *LI);
 
     SCEVCheckBlock->getTerminator()->eraseFromParent();
     SCEVCheckBlock->moveBefore(LoopVectorPreHeader);
@@ -2122,9 +2119,6 @@ class GeneratedRTChecks {
     DT->changeImmediateDominator(LoopVectorPreHeader, MemCheckBlock);
     MemCheckBlock->moveBefore(LoopVectorPreHeader);
 
-    if (OuterLoop)
-      OuterLoop->addBasicBlockToLoop(MemCheckBlock, *LI);
-
     BranchInst &BI =
         *BranchInst::Create(Bypass, LoopVectorPreHeader, MemRuntimeCheckCond);
     if (AddBranchWeights) {