[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

2 files changed, 7 insertions, 17 deletions

diff --git a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
index f65b4d7e40d..ea305a92fc6 100644
--- a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp
@@ -321,16 +321,6 @@ GCNScheduleDAGMILive::GCNScheduleDAGMILive(MachineSchedContext *C,
   DEBUG(dbgs() << "Starting occupancy is " << StartingOccupancy << ".\n");
 }
 
-void GCNScheduleDAGMILive::enterRegion(MachineBasicBlock *bb,
-                                       MachineBasicBlock::iterator begin,
-                                       MachineBasicBlock::iterator end,
-                                       unsigned regioninstrs) {
-  ScheduleDAGMILive::enterRegion(bb, begin, end, regioninstrs);
-
-  if (Stage == 0)
-    Regions.push_back(std::make_pair(begin, end));
-}
-
 void GCNScheduleDAGMILive::schedule() {
   std::vector<MachineInstr*> Unsched;
   Unsched.reserve(NumRegionInstrs);
@@ -345,6 +335,9 @@ void GCNScheduleDAGMILive::schedule() {
   }
 
   ScheduleDAGMILive::schedule();
+  if (Stage == 0)
+    Regions.push_back(std::make_pair(RegionBegin, RegionEnd));
+
   if (!LIS)
     return;
 
@@ -405,6 +398,8 @@ void GCNScheduleDAGMILive::schedule() {
     DEBUG(dbgs() << "Scheduling " << *MI);
   }
   RegionBegin = Unsched.front()->getIterator();
+  if (Stage == 0)
+    Regions.back() = std::make_pair(RegionBegin, RegionEnd);
 
   placeDebugValues();
 }
diff --git a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h
index daf0d71f47b..15af232704f 100644
--- a/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h
+++ b/llvm/lib/Target/AMDGPU/GCNSchedStrategy.h
@@ -75,8 +75,8 @@ class GCNScheduleDAGMILive : public ScheduleDAGMILive {
   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 @@ public:
   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;