Avoid an unnecessary call to allnodes_size(), which is linear.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61372 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 4b6469b..4a7920a 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -68,20 +68,23 @@
/// This SUnit graph is similar to the SelectionDAG, but represents flagged
/// together nodes with a single SUnit.
void ScheduleDAGSDNodes::BuildSchedUnits() {
+ // During scheduling, the NodeId field of SDNode is used to map SDNodes
+ // to their associated SUnits by holding SUnits table indices. A value
+ // of -1 means the SDNode does not yet have an associated SUnit.
+ unsigned NumNodes = 0;
+ for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
+ E = DAG->allnodes_end(); NI != E; ++NI) {
+ NI->setNodeId(-1);
+ ++NumNodes;
+ }
+
// Reserve entries in the vector for each of the SUnits we are creating. This
// ensure that reallocation of the vector won't happen, so SUnit*'s won't get
// invalidated.
// FIXME: Multiply by 2 because we may clone nodes during scheduling.
// This is a temporary workaround.
- SUnits.reserve(DAG->allnodes_size() * 2);
+ SUnits.reserve(NumNodes * 2);
- // During scheduling, the NodeId field of SDNode is used to map SDNodes
- // to their associated SUnits by holding SUnits table indices. A value
- // of -1 means the SDNode does not yet have an associated SUnit.
- for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
- E = DAG->allnodes_end(); NI != E; ++NI)
- NI->setNodeId(-1);
-
// Check to see if the scheduler cares about latencies.
bool UnitLatencies = ForceUnitLatencies();