[AIE] Add a loopclass to pinpoint a postpipeliner candidate

Author: Martien de Jong

llvm/lib/Target/AIE/AIEBasePipelinerLoopInfo.cpp

@@ -14,6 +14,8 @@
 
 #include "AIEBasePipelinerLoopInfo.h"
 #include "AIEBaseInstrInfo.h"
+#include "AIELoopClass.h"
+#include "AIESlotStatistics.h"
 #include "Utils/AIELoopUtils.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
@@ -751,6 +753,19 @@ bool ZeroOverheadLoop::preferPostPipeliner(SMSchedule &SMS) {
     return false;
   }
 
+  AIE::SlotStatistics Stats = AIE::computeSlotStatistics(*LoopBlock, &TII);
+  int LoopClass = classifyLoop(Stats);
+  LLVM_DEBUG(dbgs() << "Stats="; Stats.dumpShort();
+             dbgs() << format("\nLoopClass=%d", LoopClass));
+  switch (LoopClass) {
+  case 1000:
+    LLVM_DEBUG(dbgs() << format("PLI: Leaving loopclass %d for PostPipeliner\n",
+                                LoopClass));
+    return true;
+  default:
+    break;
+  }
+
   unsigned NS = SMS.getMaxStageCount() + 1;
   int II = SMS.getInitiationInterval();
   if (NS > LoopMaxStageCount && II < PostPipelinerCutoff) {
@@ -853,7 +868,6 @@ createAIEBasePipelinerLoopInfo(MachineInstr *EndLoop,
                                const AIEBaseInstrInfo &TII) {
   LLVM_DEBUG(dbgs() << "PLI: ----START LOOP----\n");
   LLVM_DEBUG(dbgs() << "  Trying DownCountLoop\n");
-
   DownCountLoop DCL(EndLoop, TII);
   auto Outcome = DCL.accept(EndLoop);
   if (Outcome == AIEBasePipelinerLoopInfo::Assessment::Accept) {

llvm/lib/Target/AIE/AIELoopClass.cpp

@@ -78,6 +78,10 @@ static const KernelFeatures Kernels[] = {
     {45, {{900, 300, 0, 2520, 0, 0, 3360}, {45, 45, 0, 45, 45}}},
     {46, {{0, 0, 0, 0, 2160, 0, 120, 1080}, {0, 420, 420}}},
     {47, {{0, 0, 0, 0, 360, 0, 240, 360}, {0, 60, 60}}},
+    // These are pre-regalloc
+    {1000, {{0, 0, 0, 0, 480, 0, 480, 480}, {0, 120, 120}}},
+    {1001, {{0, 0, 0, 0, 360, 0, 480, 720}, {0, 60, 60}}},
+
 };
 
 std::vector<int> getLoopClassScores(const SlotStatistics &Stats) {