[ScheduleDAG] Fix error assert target

[clearlov7e77]

Summary

[ScheduleDAG] Fix error assert target

In SUnit::removePred，N->WeakSuccsLeft is reduced but WeakSuccsLeft is checked

[kerbowa]

LGTM, thanks!

[clearlov7e77]

Thanks for the review @kerbowa. I don't think I have commit access to this repository. Could you please land this patch on my behalf ?
Name - lennyxiao
email - [e-mail]
github username - clearlov7e77

[clearlov7e77]

hello @kerbowa, this is my first patch, can it be landed？Thanks for your time.

llvm/lib/CodeGen/ScheduleDAG.cpp

if (D.isWeak()) {
       --WeakPredsLeft;
     } else {
       assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!");
       --NumPredsLeft;
     }
   }
   if (!isScheduled) {
     if (D.isWeak()) {
-      assert(WeakSuccsLeft > 0 && "WeakSuccsLeft will underflow!");
+      assert(N->WeakSuccsLeft > 0 && "WeakSuccsLeft will underflow!");
       --N->WeakSuccsLeft;
     } else {
       assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!");
       --N->NumSuccsLeft;
     }
   }
   N->Succs.erase(Succ);
   Preds.erase(I);