[PATCH] D57221: [LoopSimplifyCFG] Change logic of dead loops removal to avoid hitting asserts

[Mikael Holmén via Phabricator via llvm-commits]

uabelho added inline comments.


================
Comment at: lib/Transforms/Scalar/LoopSimplifyCFG.cpp:408-409
+        Loop *DL = LI.getLoopFor(BB);
+        if (DL->getParentLoop()) {
+          for (auto *PL = DL->getParentLoop(); PL; PL = PL->getParentLoop())
+            for (auto *BB : DL->getBlocks())
----------------
mkazantsev wrote:
> uabelho wrote:
> > Perhaps replace
> > 
> >         if (DL->getParentLoop()) {
> >           for (auto *PL = DL->getParentLoop(); PL; PL = PL->getParentLoop())
> > 
> > with
> > 
> >         while (auto *PL = DL->getParentLoop()) {
> > 
> > ?
> And loop infinitely? :) We need to change DL somehow, otherwise PL is always the same loop.
Doesn't
 DL->getParentLoop()->removeChildLoop(DL);
disconnect DL from PL, so in the next loop round DL doesn't have the old PL as parent anymore?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D57221/new/

https://reviews.llvm.org/D57221