MachineScheduler: Provide an option for node hiding cutoff and disable it by default

[oota-llvm.git] / lib / CodeGen / MachineScheduler.cpp

diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index 7cff5d12238fb37768c7c430dbbf120a2461222f..bc89b134f8546ce8181461246a7346c1c9ba40f3 100644 (file)
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -49,6 +49,11 @@ DumpCriticalPathLength("misched-dcpl", cl::Hidden,
 static cl::opt<bool> ViewMISchedDAGs("view-misched-dags", cl::Hidden,
   cl::desc("Pop up a window to show MISched dags after they are processed"));
 
+/// In some situations a few uninteresting nodes depend on nearly all other
+/// nodes in the graph, provide a cutoff to hide them.
+static cl::opt<unsigned> ViewMISchedCutoff("view-misched-cutoff", cl::Hidden,
+  cl::desc("Hide nodes with more predecessor/successor than cutoff"));
+
 static cl::opt<unsigned> MISchedCutoff("misched-cutoff", cl::Hidden,
   cl::desc("Stop scheduling after N instructions"), cl::init(~0U));
 
@@ -3278,7 +3283,10 @@ struct DOTGraphTraits<ScheduleDAGMI*> : public DefaultDOTGraphTraits {
   }
 
   static bool isNodeHidden(const SUnit *Node) {
-    return (Node->Preds.size() > 10 || Node->Succs.size() > 10);
+    if (ViewMISchedCutoff == 0)
+      return false;
+    return (Node->Preds.size() > ViewMISchedCutoff
+         || Node->Succs.size() > ViewMISchedCutoff);
   }
 
   static bool hasNodeAddressLabel(const SUnit *Node,