Fix some register-alias-related bugs in the post-RA scheduler liveness

computation code. Also, avoid adding output-depenency edges when both
defs are dead, which frequently happens with EFLAGS defs.

Compute Depth and Height lazily, and always in terms of edge latency
values. For the schedulers that don't care about latency, edge latencies
are set to 1.

Eliminate Cycle and CycleBound, and LatencyPriorityQueue's Latencies array.
These are all subsumed by the Depth and Height fields.

llvm-svn: 61073

1 files changed, 7 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 69d3045bf27..21df142ff34 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -80,6 +80,9 @@ void ScheduleDAGSDNodes::BuildSchedUnits() {
        E = DAG->allnodes_end(); NI != E; ++NI)
     NI->setNodeId(-1);
 
+  // Check to see if the scheduler cares about latencies.
+  bool UnitLatencies = ForceUnitLatencies();
+
   for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
        E = DAG->allnodes_end(); NI != E; ++NI) {
     if (isPassiveNode(NI))  // Leaf node, e.g. a TargetImmediate.
@@ -133,7 +136,10 @@ void ScheduleDAGSDNodes::BuildSchedUnits() {
     N->setNodeId(NodeSUnit->NodeNum);
 
     // Assign the Latency field of NodeSUnit using target-provided information.
-    ComputeLatency(NodeSUnit);
+    if (UnitLatencies)
+      NodeSUnit->Latency = 1;
+    else
+      ComputeLatency(NodeSUnit);
   }
   
   // Pass 2: add the preds, succs, etc.