+ // If TIBB is in a loop and DestBB is outside of that loop, split the
+ // other exit blocks of the loop that also have predecessors outside
+ // the loop, to maintain a LoopSimplify guarantee.
+ if (!TIL->contains(DestBB) &&
+ P->mustPreserveAnalysisID(LoopSimplifyID)) {
+ assert(!TIL->contains(NewBB) &&
+ "Split point for loop exit is contained in loop!");
+
+ // Update LCSSA form in the newly created exit block.
+ if (P->mustPreserveAnalysisID(LCSSAID)) {
+ SmallVector<BasicBlock *, 1> OrigPred;
+ OrigPred.push_back(TIBB);
+ CreatePHIsForSplitLoopExit(OrigPred, NewBB, DestBB);
+ }
+
+ // For each unique exit block...
+ SmallVector<BasicBlock *, 4> ExitBlocks;
+ TIL->getExitBlocks(ExitBlocks);
+ for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) {
+ // Collect all the preds that are inside the loop, and note
+ // whether there are any preds outside the loop.
+ SmallVector<BasicBlock *, 4> Preds;
+ bool HasPredOutsideOfLoop = false;
+ BasicBlock *Exit = ExitBlocks[i];
+ for (pred_iterator I = pred_begin(Exit), E = pred_end(Exit);
+ I != E; ++I)
+ if (TIL->contains(*I))
+ Preds.push_back(*I);
+ else
+ HasPredOutsideOfLoop = true;
+ // If there are any preds not in the loop, we'll need to split
+ // the edges. The Preds.empty() check is needed because a block
+ // may appear multiple times in the list. We can't use
+ // getUniqueExitBlocks above because that depends on LoopSimplify
+ // form, which we're in the process of restoring!
+ if (!Preds.empty() && HasPredOutsideOfLoop) {
+ BasicBlock *NewExitBB =
+ SplitBlockPredecessors(Exit, Preds.data(), Preds.size(),
+ "split", P);
+ if (P->mustPreserveAnalysisID(LCSSAID))
+ CreatePHIsForSplitLoopExit(Preds, NewExitBB, Exit);
+ }
+ }
+ }
+ // LCSSA form was updated above for the case where LoopSimplify is
+ // available, which means that all predecessors of loop exit blocks
+ // are within the loop. Without LoopSimplify form, it would be
+ // necessary to insert a new phi.
+ assert((!P->mustPreserveAnalysisID(LCSSAID) ||
+ P->mustPreserveAnalysisID(LoopSimplifyID)) &&
+ "SplitCriticalEdge doesn't know how to update LCCSA form "
+ "without LoopSimplify!");
+ }