[loop-unroll] Properly populate LoopInfo for loops cloned in LoopUnrollRuntime.

[fhahn]

Summary

This fixes Transforms/LoopUnroll/runtime-loop3.ll which failed with
EXTENSIVE_DEBUG, because the cloned basic blocks were not added to the
correct sub-loops in LoopUnrollRuntime.cpp.

[mzolotukhin]

Thanks for fixing it! The patch looks good to me, but I'd suggest committing it in two separate pieces: 1) factoring out addClonedBlockToLoopInfo (that should be NFC), 2) fixing CloneLoopBlocks in LoopUnrollRuntime.cpp. Also, I recommend to drop unnecessary whitespace changes.

Michael

[fhahn]

Thanks for the comments. I've committed the factoring out in https://reviews.llvm.org/rL291614 and will land the second commit from Phabricator.

lib/Transforms/Utils/LoopUnrollRuntime.cpp

static void CloneLoopBlocks(Loop *L, Value *NewIter,
   if (CreateRemainderLoop) {
     NewLoop = new Loop();
     if (ParentLoop)
       ParentLoop->addChildLoop(NewLoop);
     else
       LI->addTopLevelLoop(NewLoop);
   }
 
+  NewLoopsMap NewLoops;
+  NewLoops[L] = NewLoop;
   // For each block in the original loop, create a new copy,
   // and update the value map with the newly created values.
   for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
     BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, "." + suffix, F);
     NewBlocks.push_back(NewBB);
 
-    if (NewLoop)
-      NewLoop->addBasicBlockToLoop(NewBB, *LI);
-    else if (ParentLoop)
+    if (NewLoop) {
+      addClonedBlockToLoopInfo(*BB, NewBB, LI, NewLoops);
+    } else if (ParentLoop)
       ParentLoop->addBasicBlockToLoop(NewBB, *LI);
 
     VMap[*BB] = NewBB;
     if (Header == *BB) {
       // For the first block, add a CFG connection to this newly
       // created block.
       InsertTop->getTerminator()->setSuccessor(0, NewBB);
     }