Add a policy to enable computing SchedDFSResult.

Summary:
Make GenericScheduler compute SchedDFSResult on initialization if
the policy is set. This makes it possible to create classes
that extend GenericScheduler and rely on the results of SchedDFSResult,
e.g. to perform subtree scheduling.

NFC unless the policy is set.

Subscribers: MatzeB, hiraditya, javed.absar, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78432

diff --git a/llvm/include/llvm/CodeGen/MachineScheduler.h b/llvm/include/llvm/CodeGen/MachineScheduler.h
index 6cebaa4..f858b69 100644 (file)
--- a/llvm/include/llvm/CodeGen/MachineScheduler.h
+++ b/llvm/include/llvm/CodeGen/MachineScheduler.h
@@ -186,6 +186,9 @@ struct MachineSchedPolicy {
   // first.
   bool DisableLatencyHeuristic = false;
 
+  // Compute DFSResult for use in scheduling heuristics.
+  bool ComputeDFSResult = false;
+
   MachineSchedPolicy() = default;
 };
 

diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index 5cfc019..55b0075 100644 (file)
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -2733,6 +2733,9 @@ void GenericScheduler::initialize(ScheduleDAGMI *dag) {
   SchedModel = DAG->getSchedModel();
   TRI = DAG->TRI;
 
+  if (RegionPolicy.ComputeDFSResult)
+    DAG->computeDFSResult();
+
   Rem.init(DAG, SchedModel);
   Top.init(DAG, SchedModel, &Rem);
   Bot.init(DAG, SchedModel, &Rem);