[AMDGPU] Fix amdgpu-waves-per-eu accounting in scheduler

We cannot query this attribute from a subtarget given a machine function.
At this point attribute itself is already unavailable and can only be
obtained through MFI.

Differential Revision: https://reviews.llvm.org/D46781

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332166 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/AMDGPU/GCNIterativeScheduler.cpp

@@ -566,8 +566,9 @@ void GCNIterativeScheduler::scheduleMinReg(bool force) {
 void GCNIterativeScheduler::scheduleILP(
   bool TryMaximizeOccupancy) {
   const auto &ST = MF.getSubtarget<SISubtarget>();
+  const SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
   auto TgtOcc = std::min(ST.getOccupancyWithLocalMemSize(MF),
-                         ST.getWavesPerEU(MF.getFunction()).second);
+                         MFI->getMaxWavesPerEU());
 
   sortRegionsByPressure(TgtOcc);
   auto Occ = Regions.front()->MaxPressure.getOccupancy(ST);

lib/Target/AMDGPU/GCNSchedStrategy.cpp

@@ -314,8 +314,9 @@ GCNScheduleDAGMILive::GCNScheduleDAGMILive(MachineSchedContext *C,
   ScheduleDAGMILive(C, std::move(S)),
   ST(MF.getSubtarget<SISubtarget>()),
   MFI(*MF.getInfo<SIMachineFunctionInfo>()),
-  StartingOccupancy(ST.getOccupancyWithLocalMemSize(MFI.getLDSSize(),
-                                                    MF.getFunction())),
+  StartingOccupancy(std::min(ST.getOccupancyWithLocalMemSize(MFI.getLDSSize(),
+                                                             MF.getFunction()),
+                             MFI.getMaxWavesPerEU())),
   MinOccupancy(StartingOccupancy), Stage(0), RegionIdx(0) {
 
   DEBUG(dbgs() << "Starting occupancy is " << StartingOccupancy << ".\n");
@@ -368,6 +369,8 @@ void GCNScheduleDAGMILive::schedule() {
                                     PressureAfter.getVGPRNum(), MF);
   unsigned WavesBefore = getMaxWaves(PressureBefore.getSGPRNum(),
                                      PressureBefore.getVGPRNum(), MF);
+  WavesAfter = std::min(WavesAfter, MFI.getMaxWavesPerEU());
+  WavesBefore = std::min(WavesBefore, MFI.getMaxWavesPerEU());
   DEBUG(dbgs() << "Occupancy before scheduling: " << WavesBefore <<
                   ", after " << WavesAfter << ".\n");