Treat EntryToken nodes as "passive" so that they aren't added to the

ScheduleDAG; they don't correspond to any actual instructions so they
don't need to be scheduled.

This fixes a bug where the EntryToken was being scheduled multiple
times in some cases, though it ended up not causing any trouble because 
EntryToken doesn't expand into anything. With this fixed the schedulers
reliably schedule the expected number of units, so we can check this
with an assertion.

This requires a tweak to test/CodeGen/X86/loop-hoist.ll because it
ends up getting scheduled differently in a trivial way, though it was
enough to fool the prcontext+grep that the test does.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49701 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 6 deletions

diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
index 3ae5e13c1c..c2fae25067 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
@@ -164,21 +164,16 @@ void ScheduleDAGList::ScheduleNodeTopDown(SUnit *SU, unsigned CurCycle) {
 /// schedulers.
 void ScheduleDAGList::ListScheduleTopDown() {
   unsigned CurCycle = 0;
-  SUnit *Entry = SUnitMap[DAG.getEntryNode().Val].front();
 
   // All leaves to Available queue.
   for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
     // It is available if it has no predecessors.
-    if (SUnits[i].Preds.empty() && &SUnits[i] != Entry) {
+    if (SUnits[i].Preds.empty()) {
       AvailableQueue->push(&SUnits[i]);
       SUnits[i].isAvailable = SUnits[i].isPending = true;
     }
   }
   
-  // Emit the entry node first.
-  ScheduleNodeTopDown(Entry, CurCycle);
-  HazardRec->EmitInstruction(Entry->Node);
-  
   // While Available queue is not empty, grab the node with the highest
   // priority. If it is not ready put it back.  Schedule the node.
   std::vector<SUnit*> NotReady;