misched: Don't consider artificial edges weak edges.

For now be more conservative in case other out-of-tree schedulers rely
on the old behavior of artificial edges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167808 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/PostRASchedulerList.cpp

@@ -581,7 +581,7 @@ void SchedulePostRATDList::FixupKills(MachineBasicBlock *MBB) {
 void SchedulePostRATDList::ReleaseSucc(SUnit *SU, SDep *SuccEdge) {
   SUnit *SuccSU = SuccEdge->getSUnit();
 
-  if (SuccEdge->isArtificial()) {
+  if (SuccEdge->isWeak()) {
     --SuccSU->WeakPredsLeft;
     return;
   }