[AMDGPU] Fix recorded region boundaries in max-occupancy scheduler

This is incorrect to record region boundaries before scheduling,
it may change after scheduling. As a result second pass may see less
instructions to schedule than it should.

Differential Revision: https://reviews.llvm.org/D31434

llvm-svn: 298945
diff --git a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h
index daf0d71..15af232 100644
--- a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h
+++ b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h
@@ -75,8 +75,8 @@
   unsigned Stage;
 
   // Vecor of regions recorder for later rescheduling
-  SmallVector<std::pair<const MachineBasicBlock::iterator,
-                        const MachineBasicBlock::iterator>, 32> Regions;
+  SmallVector<std::pair<MachineBasicBlock::iterator,
+                        MachineBasicBlock::iterator>, 32> Regions;
 
   // Region live-ins.
   DenseMap<unsigned, LaneBitmask> LiveIns;
@@ -94,11 +94,6 @@
   GCNScheduleDAGMILive(MachineSchedContext *C,
                        std::unique_ptr<MachineSchedStrategy> S);
 
-  void enterRegion(MachineBasicBlock *bb,
-                   MachineBasicBlock::iterator begin,
-                   MachineBasicBlock::iterator end,
-                   unsigned regioninstrs) override;
-
   void schedule() override;
 
   void finalizeSchedule() override;