Move a few containers out of ScheduleDAGInstrs::BuildSchedGraph

and into the ScheduleDAGInstrs class, so that they don't get
destructed and re-constructed for each block. This fixes a
compile-time hot spot in the post-pass scheduler.

To help facilitate this, tidy and do some minor reorganization
in the scheduler constructor functions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62275 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp

@@ -22,9 +22,8 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
-ScheduleDAGSDNodes::ScheduleDAGSDNodes(SelectionDAG *dag, MachineBasicBlock *bb,
-                                       const TargetMachine &tm)
-  : ScheduleDAG(dag, bb, tm) {
+ScheduleDAGSDNodes::ScheduleDAGSDNodes(MachineFunction &mf)
+  : ScheduleDAG(mf) {
 }
 
 SUnit *ScheduleDAGSDNodes::Clone(SUnit *Old) {