1 files changed, 165 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/Target/Hexagon/HexagonHazardRecognizer.cpp b/contrib/llvm-project/llvm/lib/Target/Hexagon/HexagonHazardRecognizer.cpp
new file mode 100644
index 000000000000..e45126bec6ef
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Target/Hexagon/HexagonHazardRecognizer.cpp
@@ -0,0 +1,165 @@
+//===-- HexagonHazardRecognizer.cpp - Hexagon Post RA Hazard Recognizer ---===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the hazard recognizer for scheduling on Hexagon.
+// Use a DFA based hazard recognizer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "HexagonHazardRecognizer.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/ScheduleDAG.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cassert>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "post-RA-sched"
+
+void HexagonHazardRecognizer::Reset() {
+  LLVM_DEBUG(dbgs() << "Reset hazard recognizer\n");
+  Resources->clearResources();
+  PacketNum = 0;
+  UsesDotCur = nullptr;
+  DotCurPNum = -1;
+  UsesLoad = false;
+  PrefVectorStoreNew = nullptr;
+  RegDefs.clear();
+}
+
+ScheduleHazardRecognizer::HazardType
+HexagonHazardRecognizer::getHazardType(SUnit *SU, int stalls) {
+  MachineInstr *MI = SU->getInstr();
+  if (!MI || TII->isZeroCost(MI->getOpcode()))
+    return NoHazard;
+
+  if (!Resources->canReserveResources(*MI)) {
+    LLVM_DEBUG(dbgs() << "*** Hazard in cycle " << PacketNum << ", " << *MI);
+    HazardType RetVal = Hazard;
+    if (TII->mayBeNewStore(*MI)) {
+      // Make sure the register to be stored is defined by an instruction in the
+      // packet.
+      MachineOperand &MO = MI->getOperand(MI->getNumOperands() - 1);
+      if (!MO.isReg() || RegDefs.count(MO.getReg()) == 0)
+        return Hazard;
+      // The .new store version uses different resources so check if it
+      // causes a hazard.
+      MachineFunction *MF = MI->getParent()->getParent();
+      MachineInstr *NewMI =
+        MF->CreateMachineInstr(TII->get(TII->getDotNewOp(*MI)),
+                               MI->getDebugLoc());
+      if (Resources->canReserveResources(*NewMI))
+        RetVal = NoHazard;
+      LLVM_DEBUG(dbgs() << "*** Try .new version? " << (RetVal == NoHazard)
+                        << "\n");
+      MF->DeleteMachineInstr(NewMI);
+    }
+    return RetVal;
+  }
+
+  if (SU == UsesDotCur && DotCurPNum != (int)PacketNum) {
+    LLVM_DEBUG(dbgs() << "*** .cur Hazard in cycle " << PacketNum << ", "
+                      << *MI);
+    return Hazard;
+  }
+
+  return NoHazard;
+}
+
+void HexagonHazardRecognizer::AdvanceCycle() {
+  LLVM_DEBUG(dbgs() << "Advance cycle, clear state\n");
+  Resources->clearResources();
+  if (DotCurPNum != -1 && DotCurPNum != (int)PacketNum) {
+    UsesDotCur = nullptr;
+    DotCurPNum = -1;
+  }
+  UsesLoad = false;
+  PrefVectorStoreNew = nullptr;
+  PacketNum++;
+  RegDefs.clear();
+}
+
+/// Handle the cases when we prefer one instruction over another. Case 1 - we
+/// prefer not to generate multiple loads in the packet to avoid a potential
+/// bank conflict. Case 2 - if a packet contains a dot cur instruction, then we
+/// prefer the instruction that can use the dot cur result. However, if the use
+/// is not scheduled in the same packet, then prefer other instructions in the
+/// subsequent packet. Case 3 - we prefer a vector store that can be converted
+/// to a .new store. The packetizer will not generate the .new store if the
+/// store doesn't have resources to fit in the packet (but the .new store may
+/// have resources). We attempt to schedule the store as soon as possible to
+/// help packetize the two instructions together.
+bool HexagonHazardRecognizer::ShouldPreferAnother(SUnit *SU) {
+  if (PrefVectorStoreNew != nullptr && PrefVectorStoreNew != SU)
+    return true;
+  if (UsesLoad && SU->isInstr() && SU->getInstr()->mayLoad())
+    return true;
+  return UsesDotCur && ((SU == UsesDotCur) ^ (DotCurPNum == (int)PacketNum));
+}
+
+void HexagonHazardRecognizer::EmitInstruction(SUnit *SU) {
+  MachineInstr *MI = SU->getInstr();
+  if (!MI)
+    return;
+
+  // Keep the set of definitions for each packet, which is used to determine
+  // if a .new can be used.
+  for (const MachineOperand &MO : MI->operands())
+    if (MO.isReg() && MO.isDef() && !MO.isImplicit())
+      RegDefs.insert(MO.getReg());
+
+  if (TII->isZeroCost(MI->getOpcode()))
+    return;
+
+  if (!Resources->canReserveResources(*MI)) {
+    // It must be a .new store since other instructions must be able to be
+    // reserved at this point.
+    assert(TII->mayBeNewStore(*MI) && "Expecting .new store");
+    MachineFunction *MF = MI->getParent()->getParent();
+    MachineInstr *NewMI =
+        MF->CreateMachineInstr(TII->get(TII->getDotNewOp(*MI)),
+                               MI->getDebugLoc());
+    assert(Resources->canReserveResources(*NewMI));
+    Resources->reserveResources(*NewMI);
+    MF->DeleteMachineInstr(NewMI);
+  }
+  else
+    Resources->reserveResources(*MI);
+  LLVM_DEBUG(dbgs() << " Add instruction " << *MI);
+
+  // When scheduling a dot cur instruction, check if there is an instruction
+  // that can use the dot cur in the same packet. If so, we'll attempt to
+  // schedule it before other instructions. We only do this if the load has a
+  // single zero-latency use.
+  if (TII->mayBeCurLoad(*MI))
+    for (auto &S : SU->Succs)
+      if (S.isAssignedRegDep() && S.getLatency() == 0 &&
+          S.getSUnit()->NumPredsLeft == 1) {
+        UsesDotCur = S.getSUnit();
+        DotCurPNum = PacketNum;
+        break;
+      }
+  if (SU == UsesDotCur) {
+    UsesDotCur = nullptr;
+    DotCurPNum = -1;
+  }
+
+  UsesLoad = MI->mayLoad();
+
+  if (TII->isHVXVec(*MI) && !MI->mayLoad() && !MI->mayStore())
+    for (auto &S : SU->Succs)
+      if (S.isAssignedRegDep() && S.getLatency() == 0 &&
+          TII->mayBeNewStore(*S.getSUnit()->getInstr()) &&
+          Resources->canReserveResources(*S.getSUnit()->getInstr())) {
+        PrefVectorStoreNew = S.getSUnit();
+        break;
+      }
+}