In the pre-RA scheduler, maintain cmp+br proximity.

[oota-llvm.git] / lib / CodeGen / SelectionDAG / ScheduleDAGSDNodes.cpp

diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 078533be843ac23e9341a61128e337c259f0b5d9..b258e6eefe20958fe8516b1da5708b317517ee32 100644 (file)
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -87,6 +87,8 @@ SUnit *ScheduleDAGSDNodes::Clone(SUnit *Old) {
   SU->isCommutable = Old->isCommutable;
   SU->hasPhysRegDefs = Old->hasPhysRegDefs;
   SU->hasPhysRegClobbers = Old->hasPhysRegClobbers;
+  SU->isScheduleHigh = Old->isScheduleHigh;
+  SU->isScheduleLow = Old->isScheduleLow;
   SU->SchedulingPref = Old->SchedulingPref;
   Old->isCloned = true;
   return SU;
@@ -335,6 +337,12 @@ void ScheduleDAGSDNodes::BuildSchedUnits() {
       if (!HasGlueUse) break;
     }
 
+    // Schedule zero-latency TokenFactor below any nodes that may increase the
+    // schedule height. Otherwise, ancestors of the TokenFactor may appear to
+    // have false stalls.
+    if (NI->getOpcode() == ISD::TokenFactor)
+      NodeSUnit->isScheduleLow = true;
+
     // If there are glue operands involved, N is now the bottom-most node
     // of the sequence of nodes that are glued together.
     // Update the SUnit.