mirror of
https://github.com/c64scene-ar/llvm-6502.git
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f80a63fa23
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191610 91177308-0d34-0410-b5e6-96231b3b80d8
3041 lines
106 KiB
C++
3041 lines
106 KiB
C++
//===----- ScheduleDAGRRList.cpp - Reg pressure reduction list scheduler --===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This implements bottom-up and top-down register pressure reduction list
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// schedulers, using standard algorithms. The basic approach uses a priority
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// queue of available nodes to schedule. One at a time, nodes are taken from
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// the priority queue (thus in priority order), checked for legality to
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// schedule, and emitted if legal.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "pre-RA-sched"
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#include "llvm/CodeGen/SchedulerRegistry.h"
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#include "ScheduleDAGSDNodes.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
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#include "llvm/CodeGen/SelectionDAGISel.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/InlineAsm.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetLowering.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include <climits>
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using namespace llvm;
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STATISTIC(NumBacktracks, "Number of times scheduler backtracked");
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STATISTIC(NumUnfolds, "Number of nodes unfolded");
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STATISTIC(NumDups, "Number of duplicated nodes");
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STATISTIC(NumPRCopies, "Number of physical register copies");
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static RegisterScheduler
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burrListDAGScheduler("list-burr",
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"Bottom-up register reduction list scheduling",
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createBURRListDAGScheduler);
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static RegisterScheduler
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sourceListDAGScheduler("source",
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"Similar to list-burr but schedules in source "
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"order when possible",
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createSourceListDAGScheduler);
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static RegisterScheduler
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hybridListDAGScheduler("list-hybrid",
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"Bottom-up register pressure aware list scheduling "
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"which tries to balance latency and register pressure",
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createHybridListDAGScheduler);
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static RegisterScheduler
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ILPListDAGScheduler("list-ilp",
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"Bottom-up register pressure aware list scheduling "
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"which tries to balance ILP and register pressure",
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createILPListDAGScheduler);
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static cl::opt<bool> DisableSchedCycles(
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"disable-sched-cycles", cl::Hidden, cl::init(false),
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cl::desc("Disable cycle-level precision during preRA scheduling"));
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// Temporary sched=list-ilp flags until the heuristics are robust.
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// Some options are also available under sched=list-hybrid.
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static cl::opt<bool> DisableSchedRegPressure(
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"disable-sched-reg-pressure", cl::Hidden, cl::init(false),
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cl::desc("Disable regpressure priority in sched=list-ilp"));
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static cl::opt<bool> DisableSchedLiveUses(
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"disable-sched-live-uses", cl::Hidden, cl::init(true),
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cl::desc("Disable live use priority in sched=list-ilp"));
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static cl::opt<bool> DisableSchedVRegCycle(
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"disable-sched-vrcycle", cl::Hidden, cl::init(false),
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cl::desc("Disable virtual register cycle interference checks"));
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static cl::opt<bool> DisableSchedPhysRegJoin(
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"disable-sched-physreg-join", cl::Hidden, cl::init(false),
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cl::desc("Disable physreg def-use affinity"));
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static cl::opt<bool> DisableSchedStalls(
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"disable-sched-stalls", cl::Hidden, cl::init(true),
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cl::desc("Disable no-stall priority in sched=list-ilp"));
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static cl::opt<bool> DisableSchedCriticalPath(
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"disable-sched-critical-path", cl::Hidden, cl::init(false),
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cl::desc("Disable critical path priority in sched=list-ilp"));
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static cl::opt<bool> DisableSchedHeight(
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"disable-sched-height", cl::Hidden, cl::init(false),
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cl::desc("Disable scheduled-height priority in sched=list-ilp"));
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static cl::opt<bool> Disable2AddrHack(
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"disable-2addr-hack", cl::Hidden, cl::init(true),
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cl::desc("Disable scheduler's two-address hack"));
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static cl::opt<int> MaxReorderWindow(
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"max-sched-reorder", cl::Hidden, cl::init(6),
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cl::desc("Number of instructions to allow ahead of the critical path "
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"in sched=list-ilp"));
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static cl::opt<unsigned> AvgIPC(
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"sched-avg-ipc", cl::Hidden, cl::init(1),
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cl::desc("Average inst/cycle whan no target itinerary exists."));
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namespace {
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//===----------------------------------------------------------------------===//
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/// ScheduleDAGRRList - The actual register reduction list scheduler
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/// implementation. This supports both top-down and bottom-up scheduling.
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///
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class ScheduleDAGRRList : public ScheduleDAGSDNodes {
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private:
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/// NeedLatency - True if the scheduler will make use of latency information.
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///
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bool NeedLatency;
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/// AvailableQueue - The priority queue to use for the available SUnits.
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SchedulingPriorityQueue *AvailableQueue;
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/// PendingQueue - This contains all of the instructions whose operands have
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/// been issued, but their results are not ready yet (due to the latency of
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/// the operation). Once the operands becomes available, the instruction is
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/// added to the AvailableQueue.
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std::vector<SUnit*> PendingQueue;
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/// HazardRec - The hazard recognizer to use.
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ScheduleHazardRecognizer *HazardRec;
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/// CurCycle - The current scheduler state corresponds to this cycle.
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unsigned CurCycle;
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/// MinAvailableCycle - Cycle of the soonest available instruction.
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unsigned MinAvailableCycle;
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/// IssueCount - Count instructions issued in this cycle
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/// Currently valid only for bottom-up scheduling.
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unsigned IssueCount;
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/// LiveRegDefs - A set of physical registers and their definition
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/// that are "live". These nodes must be scheduled before any other nodes that
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/// modifies the registers can be scheduled.
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unsigned NumLiveRegs;
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std::vector<SUnit*> LiveRegDefs;
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std::vector<SUnit*> LiveRegGens;
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// Collect interferences between physical register use/defs.
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// Each interference is an SUnit and set of physical registers.
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SmallVector<SUnit*, 4> Interferences;
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typedef DenseMap<SUnit*, SmallVector<unsigned, 4> > LRegsMapT;
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LRegsMapT LRegsMap;
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/// Topo - A topological ordering for SUnits which permits fast IsReachable
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/// and similar queries.
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ScheduleDAGTopologicalSort Topo;
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// Hack to keep track of the inverse of FindCallSeqStart without more crazy
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// DAG crawling.
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DenseMap<SUnit*, SUnit*> CallSeqEndForStart;
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public:
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ScheduleDAGRRList(MachineFunction &mf, bool needlatency,
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SchedulingPriorityQueue *availqueue,
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CodeGenOpt::Level OptLevel)
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: ScheduleDAGSDNodes(mf),
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NeedLatency(needlatency), AvailableQueue(availqueue), CurCycle(0),
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Topo(SUnits, NULL) {
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const TargetMachine &tm = mf.getTarget();
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if (DisableSchedCycles || !NeedLatency)
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HazardRec = new ScheduleHazardRecognizer();
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else
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HazardRec = tm.getInstrInfo()->CreateTargetHazardRecognizer(&tm, this);
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}
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~ScheduleDAGRRList() {
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delete HazardRec;
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delete AvailableQueue;
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}
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void Schedule();
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ScheduleHazardRecognizer *getHazardRec() { return HazardRec; }
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/// IsReachable - Checks if SU is reachable from TargetSU.
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bool IsReachable(const SUnit *SU, const SUnit *TargetSU) {
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return Topo.IsReachable(SU, TargetSU);
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}
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/// WillCreateCycle - Returns true if adding an edge from SU to TargetSU will
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/// create a cycle.
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bool WillCreateCycle(SUnit *SU, SUnit *TargetSU) {
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return Topo.WillCreateCycle(SU, TargetSU);
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}
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/// AddPred - adds a predecessor edge to SUnit SU.
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/// This returns true if this is a new predecessor.
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/// Updates the topological ordering if required.
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void AddPred(SUnit *SU, const SDep &D) {
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Topo.AddPred(SU, D.getSUnit());
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SU->addPred(D);
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}
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/// RemovePred - removes a predecessor edge from SUnit SU.
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/// This returns true if an edge was removed.
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/// Updates the topological ordering if required.
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void RemovePred(SUnit *SU, const SDep &D) {
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Topo.RemovePred(SU, D.getSUnit());
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SU->removePred(D);
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}
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private:
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bool isReady(SUnit *SU) {
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return DisableSchedCycles || !AvailableQueue->hasReadyFilter() ||
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AvailableQueue->isReady(SU);
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}
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void ReleasePred(SUnit *SU, const SDep *PredEdge);
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void ReleasePredecessors(SUnit *SU);
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void ReleasePending();
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void AdvanceToCycle(unsigned NextCycle);
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void AdvancePastStalls(SUnit *SU);
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void EmitNode(SUnit *SU);
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void ScheduleNodeBottomUp(SUnit*);
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void CapturePred(SDep *PredEdge);
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void UnscheduleNodeBottomUp(SUnit*);
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void RestoreHazardCheckerBottomUp();
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void BacktrackBottomUp(SUnit*, SUnit*);
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SUnit *CopyAndMoveSuccessors(SUnit*);
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void InsertCopiesAndMoveSuccs(SUnit*, unsigned,
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const TargetRegisterClass*,
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const TargetRegisterClass*,
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SmallVectorImpl<SUnit*>&);
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bool DelayForLiveRegsBottomUp(SUnit*, SmallVectorImpl<unsigned>&);
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void releaseInterferences(unsigned Reg = 0);
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SUnit *PickNodeToScheduleBottomUp();
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void ListScheduleBottomUp();
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/// CreateNewSUnit - Creates a new SUnit and returns a pointer to it.
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/// Updates the topological ordering if required.
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SUnit *CreateNewSUnit(SDNode *N) {
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unsigned NumSUnits = SUnits.size();
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SUnit *NewNode = newSUnit(N);
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// Update the topological ordering.
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if (NewNode->NodeNum >= NumSUnits)
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Topo.InitDAGTopologicalSorting();
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return NewNode;
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}
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/// CreateClone - Creates a new SUnit from an existing one.
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/// Updates the topological ordering if required.
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SUnit *CreateClone(SUnit *N) {
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unsigned NumSUnits = SUnits.size();
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SUnit *NewNode = Clone(N);
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// Update the topological ordering.
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if (NewNode->NodeNum >= NumSUnits)
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Topo.InitDAGTopologicalSorting();
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return NewNode;
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}
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/// forceUnitLatencies - Register-pressure-reducing scheduling doesn't
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/// need actual latency information but the hybrid scheduler does.
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bool forceUnitLatencies() const {
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return !NeedLatency;
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}
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};
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} // end anonymous namespace
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/// GetCostForDef - Looks up the register class and cost for a given definition.
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/// Typically this just means looking up the representative register class,
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/// but for untyped values (MVT::Untyped) it means inspecting the node's
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/// opcode to determine what register class is being generated.
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static void GetCostForDef(const ScheduleDAGSDNodes::RegDefIter &RegDefPos,
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const TargetLowering *TLI,
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const TargetInstrInfo *TII,
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const TargetRegisterInfo *TRI,
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unsigned &RegClass, unsigned &Cost,
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const MachineFunction &MF) {
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MVT VT = RegDefPos.GetValue();
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// Special handling for untyped values. These values can only come from
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// the expansion of custom DAG-to-DAG patterns.
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if (VT == MVT::Untyped) {
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const SDNode *Node = RegDefPos.GetNode();
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// Special handling for CopyFromReg of untyped values.
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if (!Node->isMachineOpcode() && Node->getOpcode() == ISD::CopyFromReg) {
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unsigned Reg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
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const TargetRegisterClass *RC = MF.getRegInfo().getRegClass(Reg);
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RegClass = RC->getID();
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Cost = 1;
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return;
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}
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unsigned Opcode = Node->getMachineOpcode();
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if (Opcode == TargetOpcode::REG_SEQUENCE) {
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unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue();
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const TargetRegisterClass *RC = TRI->getRegClass(DstRCIdx);
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RegClass = RC->getID();
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Cost = 1;
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return;
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}
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unsigned Idx = RegDefPos.GetIdx();
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const MCInstrDesc Desc = TII->get(Opcode);
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const TargetRegisterClass *RC = TII->getRegClass(Desc, Idx, TRI, MF);
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RegClass = RC->getID();
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// FIXME: Cost arbitrarily set to 1 because there doesn't seem to be a
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// better way to determine it.
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Cost = 1;
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} else {
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RegClass = TLI->getRepRegClassFor(VT)->getID();
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Cost = TLI->getRepRegClassCostFor(VT);
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}
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}
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/// Schedule - Schedule the DAG using list scheduling.
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void ScheduleDAGRRList::Schedule() {
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DEBUG(dbgs()
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<< "********** List Scheduling BB#" << BB->getNumber()
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<< " '" << BB->getName() << "' **********\n");
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CurCycle = 0;
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IssueCount = 0;
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MinAvailableCycle = DisableSchedCycles ? 0 : UINT_MAX;
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NumLiveRegs = 0;
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// Allocate slots for each physical register, plus one for a special register
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// to track the virtual resource of a calling sequence.
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LiveRegDefs.resize(TRI->getNumRegs() + 1, NULL);
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LiveRegGens.resize(TRI->getNumRegs() + 1, NULL);
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CallSeqEndForStart.clear();
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assert(Interferences.empty() && LRegsMap.empty() && "stale Interferences");
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// Build the scheduling graph.
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BuildSchedGraph(NULL);
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DEBUG(for (unsigned su = 0, e = SUnits.size(); su != e; ++su)
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SUnits[su].dumpAll(this));
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Topo.InitDAGTopologicalSorting();
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AvailableQueue->initNodes(SUnits);
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HazardRec->Reset();
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// Execute the actual scheduling loop.
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ListScheduleBottomUp();
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AvailableQueue->releaseState();
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DEBUG({
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dbgs() << "*** Final schedule ***\n";
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dumpSchedule();
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dbgs() << '\n';
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});
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}
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//===----------------------------------------------------------------------===//
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// Bottom-Up Scheduling
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//===----------------------------------------------------------------------===//
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/// ReleasePred - Decrement the NumSuccsLeft count of a predecessor. Add it to
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/// the AvailableQueue if the count reaches zero. Also update its cycle bound.
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void ScheduleDAGRRList::ReleasePred(SUnit *SU, const SDep *PredEdge) {
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SUnit *PredSU = PredEdge->getSUnit();
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#ifndef NDEBUG
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if (PredSU->NumSuccsLeft == 0) {
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dbgs() << "*** Scheduling failed! ***\n";
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PredSU->dump(this);
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dbgs() << " has been released too many times!\n";
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llvm_unreachable(0);
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}
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#endif
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--PredSU->NumSuccsLeft;
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if (!forceUnitLatencies()) {
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// Updating predecessor's height. This is now the cycle when the
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// predecessor can be scheduled without causing a pipeline stall.
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PredSU->setHeightToAtLeast(SU->getHeight() + PredEdge->getLatency());
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}
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// If all the node's successors are scheduled, this node is ready
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// to be scheduled. Ignore the special EntrySU node.
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if (PredSU->NumSuccsLeft == 0 && PredSU != &EntrySU) {
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PredSU->isAvailable = true;
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unsigned Height = PredSU->getHeight();
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if (Height < MinAvailableCycle)
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MinAvailableCycle = Height;
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if (isReady(PredSU)) {
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AvailableQueue->push(PredSU);
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}
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// CapturePred and others may have left the node in the pending queue, avoid
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// adding it twice.
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else if (!PredSU->isPending) {
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PredSU->isPending = true;
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PendingQueue.push_back(PredSU);
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}
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}
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}
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/// IsChainDependent - Test if Outer is reachable from Inner through
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/// chain dependencies.
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static bool IsChainDependent(SDNode *Outer, SDNode *Inner,
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unsigned NestLevel,
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const TargetInstrInfo *TII) {
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SDNode *N = Outer;
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for (;;) {
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if (N == Inner)
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return true;
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// For a TokenFactor, examine each operand. There may be multiple ways
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// to get to the CALLSEQ_BEGIN, but we need to find the path with the
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// most nesting in order to ensure that we find the corresponding match.
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if (N->getOpcode() == ISD::TokenFactor) {
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for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
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if (IsChainDependent(N->getOperand(i).getNode(), Inner, NestLevel, TII))
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return true;
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return false;
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}
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// Check for a lowered CALLSEQ_BEGIN or CALLSEQ_END.
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if (N->isMachineOpcode()) {
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if (N->getMachineOpcode() ==
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(unsigned)TII->getCallFrameDestroyOpcode()) {
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++NestLevel;
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} else if (N->getMachineOpcode() ==
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(unsigned)TII->getCallFrameSetupOpcode()) {
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if (NestLevel == 0)
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return false;
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--NestLevel;
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}
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}
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// Otherwise, find the chain and continue climbing.
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for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
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if (N->getOperand(i).getValueType() == MVT::Other) {
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N = N->getOperand(i).getNode();
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goto found_chain_operand;
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}
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return false;
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found_chain_operand:;
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if (N->getOpcode() == ISD::EntryToken)
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return false;
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}
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}
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/// FindCallSeqStart - Starting from the (lowered) CALLSEQ_END node, locate
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/// the corresponding (lowered) CALLSEQ_BEGIN node.
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///
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/// NestLevel and MaxNested are used in recursion to indcate the current level
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/// of nesting of CALLSEQ_BEGIN and CALLSEQ_END pairs, as well as the maximum
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/// level seen so far.
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///
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/// TODO: It would be better to give CALLSEQ_END an explicit operand to point
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/// to the corresponding CALLSEQ_BEGIN to avoid needing to search for it.
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static SDNode *
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FindCallSeqStart(SDNode *N, unsigned &NestLevel, unsigned &MaxNest,
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const TargetInstrInfo *TII) {
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for (;;) {
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// For a TokenFactor, examine each operand. There may be multiple ways
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// to get to the CALLSEQ_BEGIN, but we need to find the path with the
|
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// most nesting in order to ensure that we find the corresponding match.
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if (N->getOpcode() == ISD::TokenFactor) {
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SDNode *Best = 0;
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unsigned BestMaxNest = MaxNest;
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for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
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unsigned MyNestLevel = NestLevel;
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unsigned MyMaxNest = MaxNest;
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if (SDNode *New = FindCallSeqStart(N->getOperand(i).getNode(),
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|
MyNestLevel, MyMaxNest, TII))
|
|
if (!Best || (MyMaxNest > BestMaxNest)) {
|
|
Best = New;
|
|
BestMaxNest = MyMaxNest;
|
|
}
|
|
}
|
|
assert(Best);
|
|
MaxNest = BestMaxNest;
|
|
return Best;
|
|
}
|
|
// Check for a lowered CALLSEQ_BEGIN or CALLSEQ_END.
|
|
if (N->isMachineOpcode()) {
|
|
if (N->getMachineOpcode() ==
|
|
(unsigned)TII->getCallFrameDestroyOpcode()) {
|
|
++NestLevel;
|
|
MaxNest = std::max(MaxNest, NestLevel);
|
|
} else if (N->getMachineOpcode() ==
|
|
(unsigned)TII->getCallFrameSetupOpcode()) {
|
|
assert(NestLevel != 0);
|
|
--NestLevel;
|
|
if (NestLevel == 0)
|
|
return N;
|
|
}
|
|
}
|
|
// Otherwise, find the chain and continue climbing.
|
|
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
|
|
if (N->getOperand(i).getValueType() == MVT::Other) {
|
|
N = N->getOperand(i).getNode();
|
|
goto found_chain_operand;
|
|
}
|
|
return 0;
|
|
found_chain_operand:;
|
|
if (N->getOpcode() == ISD::EntryToken)
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/// Call ReleasePred for each predecessor, then update register live def/gen.
|
|
/// Always update LiveRegDefs for a register dependence even if the current SU
|
|
/// also defines the register. This effectively create one large live range
|
|
/// across a sequence of two-address node. This is important because the
|
|
/// entire chain must be scheduled together. Example:
|
|
///
|
|
/// flags = (3) add
|
|
/// flags = (2) addc flags
|
|
/// flags = (1) addc flags
|
|
///
|
|
/// results in
|
|
///
|
|
/// LiveRegDefs[flags] = 3
|
|
/// LiveRegGens[flags] = 1
|
|
///
|
|
/// If (2) addc is unscheduled, then (1) addc must also be unscheduled to avoid
|
|
/// interference on flags.
|
|
void ScheduleDAGRRList::ReleasePredecessors(SUnit *SU) {
|
|
// Bottom up: release predecessors
|
|
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
ReleasePred(SU, &*I);
|
|
if (I->isAssignedRegDep()) {
|
|
// This is a physical register dependency and it's impossible or
|
|
// expensive to copy the register. Make sure nothing that can
|
|
// clobber the register is scheduled between the predecessor and
|
|
// this node.
|
|
SUnit *RegDef = LiveRegDefs[I->getReg()]; (void)RegDef;
|
|
assert((!RegDef || RegDef == SU || RegDef == I->getSUnit()) &&
|
|
"interference on register dependence");
|
|
LiveRegDefs[I->getReg()] = I->getSUnit();
|
|
if (!LiveRegGens[I->getReg()]) {
|
|
++NumLiveRegs;
|
|
LiveRegGens[I->getReg()] = SU;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If we're scheduling a lowered CALLSEQ_END, find the corresponding
|
|
// CALLSEQ_BEGIN. Inject an artificial physical register dependence between
|
|
// these nodes, to prevent other calls from being interscheduled with them.
|
|
unsigned CallResource = TRI->getNumRegs();
|
|
if (!LiveRegDefs[CallResource])
|
|
for (SDNode *Node = SU->getNode(); Node; Node = Node->getGluedNode())
|
|
if (Node->isMachineOpcode() &&
|
|
Node->getMachineOpcode() == (unsigned)TII->getCallFrameDestroyOpcode()) {
|
|
unsigned NestLevel = 0;
|
|
unsigned MaxNest = 0;
|
|
SDNode *N = FindCallSeqStart(Node, NestLevel, MaxNest, TII);
|
|
|
|
SUnit *Def = &SUnits[N->getNodeId()];
|
|
CallSeqEndForStart[Def] = SU;
|
|
|
|
++NumLiveRegs;
|
|
LiveRegDefs[CallResource] = Def;
|
|
LiveRegGens[CallResource] = SU;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/// Check to see if any of the pending instructions are ready to issue. If
|
|
/// so, add them to the available queue.
|
|
void ScheduleDAGRRList::ReleasePending() {
|
|
if (DisableSchedCycles) {
|
|
assert(PendingQueue.empty() && "pending instrs not allowed in this mode");
|
|
return;
|
|
}
|
|
|
|
// If the available queue is empty, it is safe to reset MinAvailableCycle.
|
|
if (AvailableQueue->empty())
|
|
MinAvailableCycle = UINT_MAX;
|
|
|
|
// Check to see if any of the pending instructions are ready to issue. If
|
|
// so, add them to the available queue.
|
|
for (unsigned i = 0, e = PendingQueue.size(); i != e; ++i) {
|
|
unsigned ReadyCycle = PendingQueue[i]->getHeight();
|
|
if (ReadyCycle < MinAvailableCycle)
|
|
MinAvailableCycle = ReadyCycle;
|
|
|
|
if (PendingQueue[i]->isAvailable) {
|
|
if (!isReady(PendingQueue[i]))
|
|
continue;
|
|
AvailableQueue->push(PendingQueue[i]);
|
|
}
|
|
PendingQueue[i]->isPending = false;
|
|
PendingQueue[i] = PendingQueue.back();
|
|
PendingQueue.pop_back();
|
|
--i; --e;
|
|
}
|
|
}
|
|
|
|
/// Move the scheduler state forward by the specified number of Cycles.
|
|
void ScheduleDAGRRList::AdvanceToCycle(unsigned NextCycle) {
|
|
if (NextCycle <= CurCycle)
|
|
return;
|
|
|
|
IssueCount = 0;
|
|
AvailableQueue->setCurCycle(NextCycle);
|
|
if (!HazardRec->isEnabled()) {
|
|
// Bypass lots of virtual calls in case of long latency.
|
|
CurCycle = NextCycle;
|
|
}
|
|
else {
|
|
for (; CurCycle != NextCycle; ++CurCycle) {
|
|
HazardRec->RecedeCycle();
|
|
}
|
|
}
|
|
// FIXME: Instead of visiting the pending Q each time, set a dirty flag on the
|
|
// available Q to release pending nodes at least once before popping.
|
|
ReleasePending();
|
|
}
|
|
|
|
/// Move the scheduler state forward until the specified node's dependents are
|
|
/// ready and can be scheduled with no resource conflicts.
|
|
void ScheduleDAGRRList::AdvancePastStalls(SUnit *SU) {
|
|
if (DisableSchedCycles)
|
|
return;
|
|
|
|
// FIXME: Nodes such as CopyFromReg probably should not advance the current
|
|
// cycle. Otherwise, we can wrongly mask real stalls. If the non-machine node
|
|
// has predecessors the cycle will be advanced when they are scheduled.
|
|
// But given the crude nature of modeling latency though such nodes, we
|
|
// currently need to treat these nodes like real instructions.
|
|
// if (!SU->getNode() || !SU->getNode()->isMachineOpcode()) return;
|
|
|
|
unsigned ReadyCycle = SU->getHeight();
|
|
|
|
// Bump CurCycle to account for latency. We assume the latency of other
|
|
// available instructions may be hidden by the stall (not a full pipe stall).
|
|
// This updates the hazard recognizer's cycle before reserving resources for
|
|
// this instruction.
|
|
AdvanceToCycle(ReadyCycle);
|
|
|
|
// Calls are scheduled in their preceding cycle, so don't conflict with
|
|
// hazards from instructions after the call. EmitNode will reset the
|
|
// scoreboard state before emitting the call.
|
|
if (SU->isCall)
|
|
return;
|
|
|
|
// FIXME: For resource conflicts in very long non-pipelined stages, we
|
|
// should probably skip ahead here to avoid useless scoreboard checks.
|
|
int Stalls = 0;
|
|
while (true) {
|
|
ScheduleHazardRecognizer::HazardType HT =
|
|
HazardRec->getHazardType(SU, -Stalls);
|
|
|
|
if (HT == ScheduleHazardRecognizer::NoHazard)
|
|
break;
|
|
|
|
++Stalls;
|
|
}
|
|
AdvanceToCycle(CurCycle + Stalls);
|
|
}
|
|
|
|
/// Record this SUnit in the HazardRecognizer.
|
|
/// Does not update CurCycle.
|
|
void ScheduleDAGRRList::EmitNode(SUnit *SU) {
|
|
if (!HazardRec->isEnabled())
|
|
return;
|
|
|
|
// Check for phys reg copy.
|
|
if (!SU->getNode())
|
|
return;
|
|
|
|
switch (SU->getNode()->getOpcode()) {
|
|
default:
|
|
assert(SU->getNode()->isMachineOpcode() &&
|
|
"This target-independent node should not be scheduled.");
|
|
break;
|
|
case ISD::MERGE_VALUES:
|
|
case ISD::TokenFactor:
|
|
case ISD::LIFETIME_START:
|
|
case ISD::LIFETIME_END:
|
|
case ISD::CopyToReg:
|
|
case ISD::CopyFromReg:
|
|
case ISD::EH_LABEL:
|
|
// Noops don't affect the scoreboard state. Copies are likely to be
|
|
// removed.
|
|
return;
|
|
case ISD::INLINEASM:
|
|
// For inline asm, clear the pipeline state.
|
|
HazardRec->Reset();
|
|
return;
|
|
}
|
|
if (SU->isCall) {
|
|
// Calls are scheduled with their preceding instructions. For bottom-up
|
|
// scheduling, clear the pipeline state before emitting.
|
|
HazardRec->Reset();
|
|
}
|
|
|
|
HazardRec->EmitInstruction(SU);
|
|
}
|
|
|
|
static void resetVRegCycle(SUnit *SU);
|
|
|
|
/// ScheduleNodeBottomUp - Add the node to the schedule. Decrement the pending
|
|
/// count of its predecessors. If a predecessor pending count is zero, add it to
|
|
/// the Available queue.
|
|
void ScheduleDAGRRList::ScheduleNodeBottomUp(SUnit *SU) {
|
|
DEBUG(dbgs() << "\n*** Scheduling [" << CurCycle << "]: ");
|
|
DEBUG(SU->dump(this));
|
|
|
|
#ifndef NDEBUG
|
|
if (CurCycle < SU->getHeight())
|
|
DEBUG(dbgs() << " Height [" << SU->getHeight()
|
|
<< "] pipeline stall!\n");
|
|
#endif
|
|
|
|
// FIXME: Do not modify node height. It may interfere with
|
|
// backtracking. Instead add a "ready cycle" to SUnit. Before scheduling the
|
|
// node its ready cycle can aid heuristics, and after scheduling it can
|
|
// indicate the scheduled cycle.
|
|
SU->setHeightToAtLeast(CurCycle);
|
|
|
|
// Reserve resources for the scheduled instruction.
|
|
EmitNode(SU);
|
|
|
|
Sequence.push_back(SU);
|
|
|
|
AvailableQueue->scheduledNode(SU);
|
|
|
|
// If HazardRec is disabled, and each inst counts as one cycle, then
|
|
// advance CurCycle before ReleasePredecessors to avoid useless pushes to
|
|
// PendingQueue for schedulers that implement HasReadyFilter.
|
|
if (!HazardRec->isEnabled() && AvgIPC < 2)
|
|
AdvanceToCycle(CurCycle + 1);
|
|
|
|
// Update liveness of predecessors before successors to avoid treating a
|
|
// two-address node as a live range def.
|
|
ReleasePredecessors(SU);
|
|
|
|
// Release all the implicit physical register defs that are live.
|
|
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
|
|
I != E; ++I) {
|
|
// LiveRegDegs[I->getReg()] != SU when SU is a two-address node.
|
|
if (I->isAssignedRegDep() && LiveRegDefs[I->getReg()] == SU) {
|
|
assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
|
|
--NumLiveRegs;
|
|
LiveRegDefs[I->getReg()] = NULL;
|
|
LiveRegGens[I->getReg()] = NULL;
|
|
releaseInterferences(I->getReg());
|
|
}
|
|
}
|
|
// Release the special call resource dependence, if this is the beginning
|
|
// of a call.
|
|
unsigned CallResource = TRI->getNumRegs();
|
|
if (LiveRegDefs[CallResource] == SU)
|
|
for (const SDNode *SUNode = SU->getNode(); SUNode;
|
|
SUNode = SUNode->getGluedNode()) {
|
|
if (SUNode->isMachineOpcode() &&
|
|
SUNode->getMachineOpcode() == (unsigned)TII->getCallFrameSetupOpcode()) {
|
|
assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
|
|
--NumLiveRegs;
|
|
LiveRegDefs[CallResource] = NULL;
|
|
LiveRegGens[CallResource] = NULL;
|
|
releaseInterferences(CallResource);
|
|
}
|
|
}
|
|
|
|
resetVRegCycle(SU);
|
|
|
|
SU->isScheduled = true;
|
|
|
|
// Conditions under which the scheduler should eagerly advance the cycle:
|
|
// (1) No available instructions
|
|
// (2) All pipelines full, so available instructions must have hazards.
|
|
//
|
|
// If HazardRec is disabled, the cycle was pre-advanced before calling
|
|
// ReleasePredecessors. In that case, IssueCount should remain 0.
|
|
//
|
|
// Check AvailableQueue after ReleasePredecessors in case of zero latency.
|
|
if (HazardRec->isEnabled() || AvgIPC > 1) {
|
|
if (SU->getNode() && SU->getNode()->isMachineOpcode())
|
|
++IssueCount;
|
|
if ((HazardRec->isEnabled() && HazardRec->atIssueLimit())
|
|
|| (!HazardRec->isEnabled() && IssueCount == AvgIPC))
|
|
AdvanceToCycle(CurCycle + 1);
|
|
}
|
|
}
|
|
|
|
/// CapturePred - This does the opposite of ReleasePred. Since SU is being
|
|
/// unscheduled, incrcease the succ left count of its predecessors. Remove
|
|
/// them from AvailableQueue if necessary.
|
|
void ScheduleDAGRRList::CapturePred(SDep *PredEdge) {
|
|
SUnit *PredSU = PredEdge->getSUnit();
|
|
if (PredSU->isAvailable) {
|
|
PredSU->isAvailable = false;
|
|
if (!PredSU->isPending)
|
|
AvailableQueue->remove(PredSU);
|
|
}
|
|
|
|
assert(PredSU->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!");
|
|
++PredSU->NumSuccsLeft;
|
|
}
|
|
|
|
/// UnscheduleNodeBottomUp - Remove the node from the schedule, update its and
|
|
/// its predecessor states to reflect the change.
|
|
void ScheduleDAGRRList::UnscheduleNodeBottomUp(SUnit *SU) {
|
|
DEBUG(dbgs() << "*** Unscheduling [" << SU->getHeight() << "]: ");
|
|
DEBUG(SU->dump(this));
|
|
|
|
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
CapturePred(&*I);
|
|
if (I->isAssignedRegDep() && SU == LiveRegGens[I->getReg()]){
|
|
assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
|
|
assert(LiveRegDefs[I->getReg()] == I->getSUnit() &&
|
|
"Physical register dependency violated?");
|
|
--NumLiveRegs;
|
|
LiveRegDefs[I->getReg()] = NULL;
|
|
LiveRegGens[I->getReg()] = NULL;
|
|
releaseInterferences(I->getReg());
|
|
}
|
|
}
|
|
|
|
// Reclaim the special call resource dependence, if this is the beginning
|
|
// of a call.
|
|
unsigned CallResource = TRI->getNumRegs();
|
|
for (const SDNode *SUNode = SU->getNode(); SUNode;
|
|
SUNode = SUNode->getGluedNode()) {
|
|
if (SUNode->isMachineOpcode() &&
|
|
SUNode->getMachineOpcode() == (unsigned)TII->getCallFrameSetupOpcode()) {
|
|
++NumLiveRegs;
|
|
LiveRegDefs[CallResource] = SU;
|
|
LiveRegGens[CallResource] = CallSeqEndForStart[SU];
|
|
}
|
|
}
|
|
|
|
// Release the special call resource dependence, if this is the end
|
|
// of a call.
|
|
if (LiveRegGens[CallResource] == SU)
|
|
for (const SDNode *SUNode = SU->getNode(); SUNode;
|
|
SUNode = SUNode->getGluedNode()) {
|
|
if (SUNode->isMachineOpcode() &&
|
|
SUNode->getMachineOpcode() == (unsigned)TII->getCallFrameDestroyOpcode()) {
|
|
assert(NumLiveRegs > 0 && "NumLiveRegs is already zero!");
|
|
--NumLiveRegs;
|
|
LiveRegDefs[CallResource] = NULL;
|
|
LiveRegGens[CallResource] = NULL;
|
|
releaseInterferences(CallResource);
|
|
}
|
|
}
|
|
|
|
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
|
|
I != E; ++I) {
|
|
if (I->isAssignedRegDep()) {
|
|
if (!LiveRegDefs[I->getReg()])
|
|
++NumLiveRegs;
|
|
// This becomes the nearest def. Note that an earlier def may still be
|
|
// pending if this is a two-address node.
|
|
LiveRegDefs[I->getReg()] = SU;
|
|
if (LiveRegGens[I->getReg()] == NULL ||
|
|
I->getSUnit()->getHeight() < LiveRegGens[I->getReg()]->getHeight())
|
|
LiveRegGens[I->getReg()] = I->getSUnit();
|
|
}
|
|
}
|
|
if (SU->getHeight() < MinAvailableCycle)
|
|
MinAvailableCycle = SU->getHeight();
|
|
|
|
SU->setHeightDirty();
|
|
SU->isScheduled = false;
|
|
SU->isAvailable = true;
|
|
if (!DisableSchedCycles && AvailableQueue->hasReadyFilter()) {
|
|
// Don't make available until backtracking is complete.
|
|
SU->isPending = true;
|
|
PendingQueue.push_back(SU);
|
|
}
|
|
else {
|
|
AvailableQueue->push(SU);
|
|
}
|
|
AvailableQueue->unscheduledNode(SU);
|
|
}
|
|
|
|
/// After backtracking, the hazard checker needs to be restored to a state
|
|
/// corresponding the current cycle.
|
|
void ScheduleDAGRRList::RestoreHazardCheckerBottomUp() {
|
|
HazardRec->Reset();
|
|
|
|
unsigned LookAhead = std::min((unsigned)Sequence.size(),
|
|
HazardRec->getMaxLookAhead());
|
|
if (LookAhead == 0)
|
|
return;
|
|
|
|
std::vector<SUnit*>::const_iterator I = (Sequence.end() - LookAhead);
|
|
unsigned HazardCycle = (*I)->getHeight();
|
|
for (std::vector<SUnit*>::const_iterator E = Sequence.end(); I != E; ++I) {
|
|
SUnit *SU = *I;
|
|
for (; SU->getHeight() > HazardCycle; ++HazardCycle) {
|
|
HazardRec->RecedeCycle();
|
|
}
|
|
EmitNode(SU);
|
|
}
|
|
}
|
|
|
|
/// BacktrackBottomUp - Backtrack scheduling to a previous cycle specified in
|
|
/// BTCycle in order to schedule a specific node.
|
|
void ScheduleDAGRRList::BacktrackBottomUp(SUnit *SU, SUnit *BtSU) {
|
|
SUnit *OldSU = Sequence.back();
|
|
while (true) {
|
|
Sequence.pop_back();
|
|
// FIXME: use ready cycle instead of height
|
|
CurCycle = OldSU->getHeight();
|
|
UnscheduleNodeBottomUp(OldSU);
|
|
AvailableQueue->setCurCycle(CurCycle);
|
|
if (OldSU == BtSU)
|
|
break;
|
|
OldSU = Sequence.back();
|
|
}
|
|
|
|
assert(!SU->isSucc(OldSU) && "Something is wrong!");
|
|
|
|
RestoreHazardCheckerBottomUp();
|
|
|
|
ReleasePending();
|
|
|
|
++NumBacktracks;
|
|
}
|
|
|
|
static bool isOperandOf(const SUnit *SU, SDNode *N) {
|
|
for (const SDNode *SUNode = SU->getNode(); SUNode;
|
|
SUNode = SUNode->getGluedNode()) {
|
|
if (SUNode->isOperandOf(N))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// CopyAndMoveSuccessors - Clone the specified node and move its scheduled
|
|
/// successors to the newly created node.
|
|
SUnit *ScheduleDAGRRList::CopyAndMoveSuccessors(SUnit *SU) {
|
|
SDNode *N = SU->getNode();
|
|
if (!N)
|
|
return NULL;
|
|
|
|
if (SU->getNode()->getGluedNode())
|
|
return NULL;
|
|
|
|
SUnit *NewSU;
|
|
bool TryUnfold = false;
|
|
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
|
|
EVT VT = N->getValueType(i);
|
|
if (VT == MVT::Glue)
|
|
return NULL;
|
|
else if (VT == MVT::Other)
|
|
TryUnfold = true;
|
|
}
|
|
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
|
|
const SDValue &Op = N->getOperand(i);
|
|
EVT VT = Op.getNode()->getValueType(Op.getResNo());
|
|
if (VT == MVT::Glue)
|
|
return NULL;
|
|
}
|
|
|
|
if (TryUnfold) {
|
|
SmallVector<SDNode*, 2> NewNodes;
|
|
if (!TII->unfoldMemoryOperand(*DAG, N, NewNodes))
|
|
return NULL;
|
|
|
|
// unfolding an x86 DEC64m operation results in store, dec, load which
|
|
// can't be handled here so quit
|
|
if (NewNodes.size() == 3)
|
|
return NULL;
|
|
|
|
DEBUG(dbgs() << "Unfolding SU #" << SU->NodeNum << "\n");
|
|
assert(NewNodes.size() == 2 && "Expected a load folding node!");
|
|
|
|
N = NewNodes[1];
|
|
SDNode *LoadNode = NewNodes[0];
|
|
unsigned NumVals = N->getNumValues();
|
|
unsigned OldNumVals = SU->getNode()->getNumValues();
|
|
for (unsigned i = 0; i != NumVals; ++i)
|
|
DAG->ReplaceAllUsesOfValueWith(SDValue(SU->getNode(), i), SDValue(N, i));
|
|
DAG->ReplaceAllUsesOfValueWith(SDValue(SU->getNode(), OldNumVals-1),
|
|
SDValue(LoadNode, 1));
|
|
|
|
// LoadNode may already exist. This can happen when there is another
|
|
// load from the same location and producing the same type of value
|
|
// but it has different alignment or volatileness.
|
|
bool isNewLoad = true;
|
|
SUnit *LoadSU;
|
|
if (LoadNode->getNodeId() != -1) {
|
|
LoadSU = &SUnits[LoadNode->getNodeId()];
|
|
isNewLoad = false;
|
|
} else {
|
|
LoadSU = CreateNewSUnit(LoadNode);
|
|
LoadNode->setNodeId(LoadSU->NodeNum);
|
|
|
|
InitNumRegDefsLeft(LoadSU);
|
|
computeLatency(LoadSU);
|
|
}
|
|
|
|
SUnit *NewSU = CreateNewSUnit(N);
|
|
assert(N->getNodeId() == -1 && "Node already inserted!");
|
|
N->setNodeId(NewSU->NodeNum);
|
|
|
|
const MCInstrDesc &MCID = TII->get(N->getMachineOpcode());
|
|
for (unsigned i = 0; i != MCID.getNumOperands(); ++i) {
|
|
if (MCID.getOperandConstraint(i, MCOI::TIED_TO) != -1) {
|
|
NewSU->isTwoAddress = true;
|
|
break;
|
|
}
|
|
}
|
|
if (MCID.isCommutable())
|
|
NewSU->isCommutable = true;
|
|
|
|
InitNumRegDefsLeft(NewSU);
|
|
computeLatency(NewSU);
|
|
|
|
// Record all the edges to and from the old SU, by category.
|
|
SmallVector<SDep, 4> ChainPreds;
|
|
SmallVector<SDep, 4> ChainSuccs;
|
|
SmallVector<SDep, 4> LoadPreds;
|
|
SmallVector<SDep, 4> NodePreds;
|
|
SmallVector<SDep, 4> NodeSuccs;
|
|
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl())
|
|
ChainPreds.push_back(*I);
|
|
else if (isOperandOf(I->getSUnit(), LoadNode))
|
|
LoadPreds.push_back(*I);
|
|
else
|
|
NodePreds.push_back(*I);
|
|
}
|
|
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl())
|
|
ChainSuccs.push_back(*I);
|
|
else
|
|
NodeSuccs.push_back(*I);
|
|
}
|
|
|
|
// Now assign edges to the newly-created nodes.
|
|
for (unsigned i = 0, e = ChainPreds.size(); i != e; ++i) {
|
|
const SDep &Pred = ChainPreds[i];
|
|
RemovePred(SU, Pred);
|
|
if (isNewLoad)
|
|
AddPred(LoadSU, Pred);
|
|
}
|
|
for (unsigned i = 0, e = LoadPreds.size(); i != e; ++i) {
|
|
const SDep &Pred = LoadPreds[i];
|
|
RemovePred(SU, Pred);
|
|
if (isNewLoad)
|
|
AddPred(LoadSU, Pred);
|
|
}
|
|
for (unsigned i = 0, e = NodePreds.size(); i != e; ++i) {
|
|
const SDep &Pred = NodePreds[i];
|
|
RemovePred(SU, Pred);
|
|
AddPred(NewSU, Pred);
|
|
}
|
|
for (unsigned i = 0, e = NodeSuccs.size(); i != e; ++i) {
|
|
SDep D = NodeSuccs[i];
|
|
SUnit *SuccDep = D.getSUnit();
|
|
D.setSUnit(SU);
|
|
RemovePred(SuccDep, D);
|
|
D.setSUnit(NewSU);
|
|
AddPred(SuccDep, D);
|
|
// Balance register pressure.
|
|
if (AvailableQueue->tracksRegPressure() && SuccDep->isScheduled
|
|
&& !D.isCtrl() && NewSU->NumRegDefsLeft > 0)
|
|
--NewSU->NumRegDefsLeft;
|
|
}
|
|
for (unsigned i = 0, e = ChainSuccs.size(); i != e; ++i) {
|
|
SDep D = ChainSuccs[i];
|
|
SUnit *SuccDep = D.getSUnit();
|
|
D.setSUnit(SU);
|
|
RemovePred(SuccDep, D);
|
|
if (isNewLoad) {
|
|
D.setSUnit(LoadSU);
|
|
AddPred(SuccDep, D);
|
|
}
|
|
}
|
|
|
|
// Add a data dependency to reflect that NewSU reads the value defined
|
|
// by LoadSU.
|
|
SDep D(LoadSU, SDep::Data, 0);
|
|
D.setLatency(LoadSU->Latency);
|
|
AddPred(NewSU, D);
|
|
|
|
if (isNewLoad)
|
|
AvailableQueue->addNode(LoadSU);
|
|
AvailableQueue->addNode(NewSU);
|
|
|
|
++NumUnfolds;
|
|
|
|
if (NewSU->NumSuccsLeft == 0) {
|
|
NewSU->isAvailable = true;
|
|
return NewSU;
|
|
}
|
|
SU = NewSU;
|
|
}
|
|
|
|
DEBUG(dbgs() << " Duplicating SU #" << SU->NodeNum << "\n");
|
|
NewSU = CreateClone(SU);
|
|
|
|
// New SUnit has the exact same predecessors.
|
|
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I)
|
|
if (!I->isArtificial())
|
|
AddPred(NewSU, *I);
|
|
|
|
// Only copy scheduled successors. Cut them from old node's successor
|
|
// list and move them over.
|
|
SmallVector<std::pair<SUnit *, SDep>, 4> DelDeps;
|
|
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
|
|
I != E; ++I) {
|
|
if (I->isArtificial())
|
|
continue;
|
|
SUnit *SuccSU = I->getSUnit();
|
|
if (SuccSU->isScheduled) {
|
|
SDep D = *I;
|
|
D.setSUnit(NewSU);
|
|
AddPred(SuccSU, D);
|
|
D.setSUnit(SU);
|
|
DelDeps.push_back(std::make_pair(SuccSU, D));
|
|
}
|
|
}
|
|
for (unsigned i = 0, e = DelDeps.size(); i != e; ++i)
|
|
RemovePred(DelDeps[i].first, DelDeps[i].second);
|
|
|
|
AvailableQueue->updateNode(SU);
|
|
AvailableQueue->addNode(NewSU);
|
|
|
|
++NumDups;
|
|
return NewSU;
|
|
}
|
|
|
|
/// InsertCopiesAndMoveSuccs - Insert register copies and move all
|
|
/// scheduled successors of the given SUnit to the last copy.
|
|
void ScheduleDAGRRList::InsertCopiesAndMoveSuccs(SUnit *SU, unsigned Reg,
|
|
const TargetRegisterClass *DestRC,
|
|
const TargetRegisterClass *SrcRC,
|
|
SmallVectorImpl<SUnit*> &Copies) {
|
|
SUnit *CopyFromSU = CreateNewSUnit(NULL);
|
|
CopyFromSU->CopySrcRC = SrcRC;
|
|
CopyFromSU->CopyDstRC = DestRC;
|
|
|
|
SUnit *CopyToSU = CreateNewSUnit(NULL);
|
|
CopyToSU->CopySrcRC = DestRC;
|
|
CopyToSU->CopyDstRC = SrcRC;
|
|
|
|
// Only copy scheduled successors. Cut them from old node's successor
|
|
// list and move them over.
|
|
SmallVector<std::pair<SUnit *, SDep>, 4> DelDeps;
|
|
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
|
|
I != E; ++I) {
|
|
if (I->isArtificial())
|
|
continue;
|
|
SUnit *SuccSU = I->getSUnit();
|
|
if (SuccSU->isScheduled) {
|
|
SDep D = *I;
|
|
D.setSUnit(CopyToSU);
|
|
AddPred(SuccSU, D);
|
|
DelDeps.push_back(std::make_pair(SuccSU, *I));
|
|
}
|
|
else {
|
|
// Avoid scheduling the def-side copy before other successors. Otherwise
|
|
// we could introduce another physreg interference on the copy and
|
|
// continue inserting copies indefinitely.
|
|
AddPred(SuccSU, SDep(CopyFromSU, SDep::Artificial));
|
|
}
|
|
}
|
|
for (unsigned i = 0, e = DelDeps.size(); i != e; ++i)
|
|
RemovePred(DelDeps[i].first, DelDeps[i].second);
|
|
|
|
SDep FromDep(SU, SDep::Data, Reg);
|
|
FromDep.setLatency(SU->Latency);
|
|
AddPred(CopyFromSU, FromDep);
|
|
SDep ToDep(CopyFromSU, SDep::Data, 0);
|
|
ToDep.setLatency(CopyFromSU->Latency);
|
|
AddPred(CopyToSU, ToDep);
|
|
|
|
AvailableQueue->updateNode(SU);
|
|
AvailableQueue->addNode(CopyFromSU);
|
|
AvailableQueue->addNode(CopyToSU);
|
|
Copies.push_back(CopyFromSU);
|
|
Copies.push_back(CopyToSU);
|
|
|
|
++NumPRCopies;
|
|
}
|
|
|
|
/// getPhysicalRegisterVT - Returns the ValueType of the physical register
|
|
/// definition of the specified node.
|
|
/// FIXME: Move to SelectionDAG?
|
|
static EVT getPhysicalRegisterVT(SDNode *N, unsigned Reg,
|
|
const TargetInstrInfo *TII) {
|
|
const MCInstrDesc &MCID = TII->get(N->getMachineOpcode());
|
|
assert(MCID.ImplicitDefs && "Physical reg def must be in implicit def list!");
|
|
unsigned NumRes = MCID.getNumDefs();
|
|
for (const uint16_t *ImpDef = MCID.getImplicitDefs(); *ImpDef; ++ImpDef) {
|
|
if (Reg == *ImpDef)
|
|
break;
|
|
++NumRes;
|
|
}
|
|
return N->getValueType(NumRes);
|
|
}
|
|
|
|
/// CheckForLiveRegDef - Return true and update live register vector if the
|
|
/// specified register def of the specified SUnit clobbers any "live" registers.
|
|
static void CheckForLiveRegDef(SUnit *SU, unsigned Reg,
|
|
std::vector<SUnit*> &LiveRegDefs,
|
|
SmallSet<unsigned, 4> &RegAdded,
|
|
SmallVectorImpl<unsigned> &LRegs,
|
|
const TargetRegisterInfo *TRI) {
|
|
for (MCRegAliasIterator AliasI(Reg, TRI, true); AliasI.isValid(); ++AliasI) {
|
|
|
|
// Check if Ref is live.
|
|
if (!LiveRegDefs[*AliasI]) continue;
|
|
|
|
// Allow multiple uses of the same def.
|
|
if (LiveRegDefs[*AliasI] == SU) continue;
|
|
|
|
// Add Reg to the set of interfering live regs.
|
|
if (RegAdded.insert(*AliasI)) {
|
|
LRegs.push_back(*AliasI);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// CheckForLiveRegDefMasked - Check for any live physregs that are clobbered
|
|
/// by RegMask, and add them to LRegs.
|
|
static void CheckForLiveRegDefMasked(SUnit *SU, const uint32_t *RegMask,
|
|
std::vector<SUnit*> &LiveRegDefs,
|
|
SmallSet<unsigned, 4> &RegAdded,
|
|
SmallVectorImpl<unsigned> &LRegs) {
|
|
// Look at all live registers. Skip Reg0 and the special CallResource.
|
|
for (unsigned i = 1, e = LiveRegDefs.size()-1; i != e; ++i) {
|
|
if (!LiveRegDefs[i]) continue;
|
|
if (LiveRegDefs[i] == SU) continue;
|
|
if (!MachineOperand::clobbersPhysReg(RegMask, i)) continue;
|
|
if (RegAdded.insert(i))
|
|
LRegs.push_back(i);
|
|
}
|
|
}
|
|
|
|
/// getNodeRegMask - Returns the register mask attached to an SDNode, if any.
|
|
static const uint32_t *getNodeRegMask(const SDNode *N) {
|
|
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
|
|
if (const RegisterMaskSDNode *Op =
|
|
dyn_cast<RegisterMaskSDNode>(N->getOperand(i).getNode()))
|
|
return Op->getRegMask();
|
|
return NULL;
|
|
}
|
|
|
|
/// DelayForLiveRegsBottomUp - Returns true if it is necessary to delay
|
|
/// scheduling of the given node to satisfy live physical register dependencies.
|
|
/// If the specific node is the last one that's available to schedule, do
|
|
/// whatever is necessary (i.e. backtracking or cloning) to make it possible.
|
|
bool ScheduleDAGRRList::
|
|
DelayForLiveRegsBottomUp(SUnit *SU, SmallVectorImpl<unsigned> &LRegs) {
|
|
if (NumLiveRegs == 0)
|
|
return false;
|
|
|
|
SmallSet<unsigned, 4> RegAdded;
|
|
// If this node would clobber any "live" register, then it's not ready.
|
|
//
|
|
// If SU is the currently live definition of the same register that it uses,
|
|
// then we are free to schedule it.
|
|
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isAssignedRegDep() && LiveRegDefs[I->getReg()] != SU)
|
|
CheckForLiveRegDef(I->getSUnit(), I->getReg(), LiveRegDefs,
|
|
RegAdded, LRegs, TRI);
|
|
}
|
|
|
|
for (SDNode *Node = SU->getNode(); Node; Node = Node->getGluedNode()) {
|
|
if (Node->getOpcode() == ISD::INLINEASM) {
|
|
// Inline asm can clobber physical defs.
|
|
unsigned NumOps = Node->getNumOperands();
|
|
if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue)
|
|
--NumOps; // Ignore the glue operand.
|
|
|
|
for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) {
|
|
unsigned Flags =
|
|
cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue();
|
|
unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
|
|
|
|
++i; // Skip the ID value.
|
|
if (InlineAsm::isRegDefKind(Flags) ||
|
|
InlineAsm::isRegDefEarlyClobberKind(Flags) ||
|
|
InlineAsm::isClobberKind(Flags)) {
|
|
// Check for def of register or earlyclobber register.
|
|
for (; NumVals; --NumVals, ++i) {
|
|
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
|
|
if (TargetRegisterInfo::isPhysicalRegister(Reg))
|
|
CheckForLiveRegDef(SU, Reg, LiveRegDefs, RegAdded, LRegs, TRI);
|
|
}
|
|
} else
|
|
i += NumVals;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (!Node->isMachineOpcode())
|
|
continue;
|
|
// If we're in the middle of scheduling a call, don't begin scheduling
|
|
// another call. Also, don't allow any physical registers to be live across
|
|
// the call.
|
|
if (Node->getMachineOpcode() == (unsigned)TII->getCallFrameDestroyOpcode()) {
|
|
// Check the special calling-sequence resource.
|
|
unsigned CallResource = TRI->getNumRegs();
|
|
if (LiveRegDefs[CallResource]) {
|
|
SDNode *Gen = LiveRegGens[CallResource]->getNode();
|
|
while (SDNode *Glued = Gen->getGluedNode())
|
|
Gen = Glued;
|
|
if (!IsChainDependent(Gen, Node, 0, TII) && RegAdded.insert(CallResource))
|
|
LRegs.push_back(CallResource);
|
|
}
|
|
}
|
|
if (const uint32_t *RegMask = getNodeRegMask(Node))
|
|
CheckForLiveRegDefMasked(SU, RegMask, LiveRegDefs, RegAdded, LRegs);
|
|
|
|
const MCInstrDesc &MCID = TII->get(Node->getMachineOpcode());
|
|
if (!MCID.ImplicitDefs)
|
|
continue;
|
|
for (const uint16_t *Reg = MCID.getImplicitDefs(); *Reg; ++Reg)
|
|
CheckForLiveRegDef(SU, *Reg, LiveRegDefs, RegAdded, LRegs, TRI);
|
|
}
|
|
|
|
return !LRegs.empty();
|
|
}
|
|
|
|
void ScheduleDAGRRList::releaseInterferences(unsigned Reg) {
|
|
// Add the nodes that aren't ready back onto the available list.
|
|
for (unsigned i = Interferences.size(); i > 0; --i) {
|
|
SUnit *SU = Interferences[i-1];
|
|
LRegsMapT::iterator LRegsPos = LRegsMap.find(SU);
|
|
if (Reg) {
|
|
SmallVectorImpl<unsigned> &LRegs = LRegsPos->second;
|
|
if (std::find(LRegs.begin(), LRegs.end(), Reg) == LRegs.end())
|
|
continue;
|
|
}
|
|
SU->isPending = false;
|
|
// The interfering node may no longer be available due to backtracking.
|
|
// Furthermore, it may have been made available again, in which case it is
|
|
// now already in the AvailableQueue.
|
|
if (SU->isAvailable && !SU->NodeQueueId) {
|
|
DEBUG(dbgs() << " Repushing SU #" << SU->NodeNum << '\n');
|
|
AvailableQueue->push(SU);
|
|
}
|
|
if (i < Interferences.size())
|
|
Interferences[i-1] = Interferences.back();
|
|
Interferences.pop_back();
|
|
LRegsMap.erase(LRegsPos);
|
|
}
|
|
}
|
|
|
|
/// Return a node that can be scheduled in this cycle. Requirements:
|
|
/// (1) Ready: latency has been satisfied
|
|
/// (2) No Hazards: resources are available
|
|
/// (3) No Interferences: may unschedule to break register interferences.
|
|
SUnit *ScheduleDAGRRList::PickNodeToScheduleBottomUp() {
|
|
SUnit *CurSU = AvailableQueue->empty() ? 0 : AvailableQueue->pop();
|
|
while (CurSU) {
|
|
SmallVector<unsigned, 4> LRegs;
|
|
if (!DelayForLiveRegsBottomUp(CurSU, LRegs))
|
|
break;
|
|
DEBUG(dbgs() << " Interfering reg " <<
|
|
(LRegs[0] == TRI->getNumRegs() ? "CallResource"
|
|
: TRI->getName(LRegs[0]))
|
|
<< " SU #" << CurSU->NodeNum << '\n');
|
|
std::pair<LRegsMapT::iterator, bool> LRegsPair =
|
|
LRegsMap.insert(std::make_pair(CurSU, LRegs));
|
|
if (LRegsPair.second) {
|
|
CurSU->isPending = true; // This SU is not in AvailableQueue right now.
|
|
Interferences.push_back(CurSU);
|
|
}
|
|
else {
|
|
assert(CurSU->isPending && "Intereferences are pending");
|
|
// Update the interference with current live regs.
|
|
LRegsPair.first->second = LRegs;
|
|
}
|
|
CurSU = AvailableQueue->pop();
|
|
}
|
|
if (CurSU)
|
|
return CurSU;
|
|
|
|
// All candidates are delayed due to live physical reg dependencies.
|
|
// Try backtracking, code duplication, or inserting cross class copies
|
|
// to resolve it.
|
|
for (unsigned i = 0, e = Interferences.size(); i != e; ++i) {
|
|
SUnit *TrySU = Interferences[i];
|
|
SmallVectorImpl<unsigned> &LRegs = LRegsMap[TrySU];
|
|
|
|
// Try unscheduling up to the point where it's safe to schedule
|
|
// this node.
|
|
SUnit *BtSU = NULL;
|
|
unsigned LiveCycle = UINT_MAX;
|
|
for (unsigned j = 0, ee = LRegs.size(); j != ee; ++j) {
|
|
unsigned Reg = LRegs[j];
|
|
if (LiveRegGens[Reg]->getHeight() < LiveCycle) {
|
|
BtSU = LiveRegGens[Reg];
|
|
LiveCycle = BtSU->getHeight();
|
|
}
|
|
}
|
|
if (!WillCreateCycle(TrySU, BtSU)) {
|
|
// BacktrackBottomUp mutates Interferences!
|
|
BacktrackBottomUp(TrySU, BtSU);
|
|
|
|
// Force the current node to be scheduled before the node that
|
|
// requires the physical reg dep.
|
|
if (BtSU->isAvailable) {
|
|
BtSU->isAvailable = false;
|
|
if (!BtSU->isPending)
|
|
AvailableQueue->remove(BtSU);
|
|
}
|
|
DEBUG(dbgs() << "ARTIFICIAL edge from SU(" << BtSU->NodeNum << ") to SU("
|
|
<< TrySU->NodeNum << ")\n");
|
|
AddPred(TrySU, SDep(BtSU, SDep::Artificial));
|
|
|
|
// If one or more successors has been unscheduled, then the current
|
|
// node is no longer available.
|
|
if (!TrySU->isAvailable)
|
|
CurSU = AvailableQueue->pop();
|
|
else {
|
|
AvailableQueue->remove(TrySU);
|
|
CurSU = TrySU;
|
|
}
|
|
// Interferences has been mutated. We must break.
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!CurSU) {
|
|
// Can't backtrack. If it's too expensive to copy the value, then try
|
|
// duplicate the nodes that produces these "too expensive to copy"
|
|
// values to break the dependency. In case even that doesn't work,
|
|
// insert cross class copies.
|
|
// If it's not too expensive, i.e. cost != -1, issue copies.
|
|
SUnit *TrySU = Interferences[0];
|
|
SmallVectorImpl<unsigned> &LRegs = LRegsMap[TrySU];
|
|
assert(LRegs.size() == 1 && "Can't handle this yet!");
|
|
unsigned Reg = LRegs[0];
|
|
SUnit *LRDef = LiveRegDefs[Reg];
|
|
EVT VT = getPhysicalRegisterVT(LRDef->getNode(), Reg, TII);
|
|
const TargetRegisterClass *RC =
|
|
TRI->getMinimalPhysRegClass(Reg, VT);
|
|
const TargetRegisterClass *DestRC = TRI->getCrossCopyRegClass(RC);
|
|
|
|
// If cross copy register class is the same as RC, then it must be possible
|
|
// copy the value directly. Do not try duplicate the def.
|
|
// If cross copy register class is not the same as RC, then it's possible to
|
|
// copy the value but it require cross register class copies and it is
|
|
// expensive.
|
|
// If cross copy register class is null, then it's not possible to copy
|
|
// the value at all.
|
|
SUnit *NewDef = 0;
|
|
if (DestRC != RC) {
|
|
NewDef = CopyAndMoveSuccessors(LRDef);
|
|
if (!DestRC && !NewDef)
|
|
report_fatal_error("Can't handle live physical register dependency!");
|
|
}
|
|
if (!NewDef) {
|
|
// Issue copies, these can be expensive cross register class copies.
|
|
SmallVector<SUnit*, 2> Copies;
|
|
InsertCopiesAndMoveSuccs(LRDef, Reg, DestRC, RC, Copies);
|
|
DEBUG(dbgs() << " Adding an edge from SU #" << TrySU->NodeNum
|
|
<< " to SU #" << Copies.front()->NodeNum << "\n");
|
|
AddPred(TrySU, SDep(Copies.front(), SDep::Artificial));
|
|
NewDef = Copies.back();
|
|
}
|
|
|
|
DEBUG(dbgs() << " Adding an edge from SU #" << NewDef->NodeNum
|
|
<< " to SU #" << TrySU->NodeNum << "\n");
|
|
LiveRegDefs[Reg] = NewDef;
|
|
AddPred(NewDef, SDep(TrySU, SDep::Artificial));
|
|
TrySU->isAvailable = false;
|
|
CurSU = NewDef;
|
|
}
|
|
assert(CurSU && "Unable to resolve live physical register dependencies!");
|
|
return CurSU;
|
|
}
|
|
|
|
/// ListScheduleBottomUp - The main loop of list scheduling for bottom-up
|
|
/// schedulers.
|
|
void ScheduleDAGRRList::ListScheduleBottomUp() {
|
|
// Release any predecessors of the special Exit node.
|
|
ReleasePredecessors(&ExitSU);
|
|
|
|
// Add root to Available queue.
|
|
if (!SUnits.empty()) {
|
|
SUnit *RootSU = &SUnits[DAG->getRoot().getNode()->getNodeId()];
|
|
assert(RootSU->Succs.empty() && "Graph root shouldn't have successors!");
|
|
RootSU->isAvailable = true;
|
|
AvailableQueue->push(RootSU);
|
|
}
|
|
|
|
// While Available queue is not empty, grab the node with the highest
|
|
// priority. If it is not ready put it back. Schedule the node.
|
|
Sequence.reserve(SUnits.size());
|
|
while (!AvailableQueue->empty() || !Interferences.empty()) {
|
|
DEBUG(dbgs() << "\nExamining Available:\n";
|
|
AvailableQueue->dump(this));
|
|
|
|
// Pick the best node to schedule taking all constraints into
|
|
// consideration.
|
|
SUnit *SU = PickNodeToScheduleBottomUp();
|
|
|
|
AdvancePastStalls(SU);
|
|
|
|
ScheduleNodeBottomUp(SU);
|
|
|
|
while (AvailableQueue->empty() && !PendingQueue.empty()) {
|
|
// Advance the cycle to free resources. Skip ahead to the next ready SU.
|
|
assert(MinAvailableCycle < UINT_MAX && "MinAvailableCycle uninitialized");
|
|
AdvanceToCycle(std::max(CurCycle + 1, MinAvailableCycle));
|
|
}
|
|
}
|
|
|
|
// Reverse the order if it is bottom up.
|
|
std::reverse(Sequence.begin(), Sequence.end());
|
|
|
|
#ifndef NDEBUG
|
|
VerifyScheduledSequence(/*isBottomUp=*/true);
|
|
#endif
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// RegReductionPriorityQueue Definition
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This is a SchedulingPriorityQueue that schedules using Sethi Ullman numbers
|
|
// to reduce register pressure.
|
|
//
|
|
namespace {
|
|
class RegReductionPQBase;
|
|
|
|
struct queue_sort : public std::binary_function<SUnit*, SUnit*, bool> {
|
|
bool isReady(SUnit* SU, unsigned CurCycle) const { return true; }
|
|
};
|
|
|
|
#ifndef NDEBUG
|
|
template<class SF>
|
|
struct reverse_sort : public queue_sort {
|
|
SF &SortFunc;
|
|
reverse_sort(SF &sf) : SortFunc(sf) {}
|
|
reverse_sort(const reverse_sort &RHS) : SortFunc(RHS.SortFunc) {}
|
|
|
|
bool operator()(SUnit* left, SUnit* right) const {
|
|
// reverse left/right rather than simply !SortFunc(left, right)
|
|
// to expose different paths in the comparison logic.
|
|
return SortFunc(right, left);
|
|
}
|
|
};
|
|
#endif // NDEBUG
|
|
|
|
/// bu_ls_rr_sort - Priority function for bottom up register pressure
|
|
// reduction scheduler.
|
|
struct bu_ls_rr_sort : public queue_sort {
|
|
enum {
|
|
IsBottomUp = true,
|
|
HasReadyFilter = false
|
|
};
|
|
|
|
RegReductionPQBase *SPQ;
|
|
bu_ls_rr_sort(RegReductionPQBase *spq) : SPQ(spq) {}
|
|
bu_ls_rr_sort(const bu_ls_rr_sort &RHS) : SPQ(RHS.SPQ) {}
|
|
|
|
bool operator()(SUnit* left, SUnit* right) const;
|
|
};
|
|
|
|
// src_ls_rr_sort - Priority function for source order scheduler.
|
|
struct src_ls_rr_sort : public queue_sort {
|
|
enum {
|
|
IsBottomUp = true,
|
|
HasReadyFilter = false
|
|
};
|
|
|
|
RegReductionPQBase *SPQ;
|
|
src_ls_rr_sort(RegReductionPQBase *spq)
|
|
: SPQ(spq) {}
|
|
src_ls_rr_sort(const src_ls_rr_sort &RHS)
|
|
: SPQ(RHS.SPQ) {}
|
|
|
|
bool operator()(SUnit* left, SUnit* right) const;
|
|
};
|
|
|
|
// hybrid_ls_rr_sort - Priority function for hybrid scheduler.
|
|
struct hybrid_ls_rr_sort : public queue_sort {
|
|
enum {
|
|
IsBottomUp = true,
|
|
HasReadyFilter = false
|
|
};
|
|
|
|
RegReductionPQBase *SPQ;
|
|
hybrid_ls_rr_sort(RegReductionPQBase *spq)
|
|
: SPQ(spq) {}
|
|
hybrid_ls_rr_sort(const hybrid_ls_rr_sort &RHS)
|
|
: SPQ(RHS.SPQ) {}
|
|
|
|
bool isReady(SUnit *SU, unsigned CurCycle) const;
|
|
|
|
bool operator()(SUnit* left, SUnit* right) const;
|
|
};
|
|
|
|
// ilp_ls_rr_sort - Priority function for ILP (instruction level parallelism)
|
|
// scheduler.
|
|
struct ilp_ls_rr_sort : public queue_sort {
|
|
enum {
|
|
IsBottomUp = true,
|
|
HasReadyFilter = false
|
|
};
|
|
|
|
RegReductionPQBase *SPQ;
|
|
ilp_ls_rr_sort(RegReductionPQBase *spq)
|
|
: SPQ(spq) {}
|
|
ilp_ls_rr_sort(const ilp_ls_rr_sort &RHS)
|
|
: SPQ(RHS.SPQ) {}
|
|
|
|
bool isReady(SUnit *SU, unsigned CurCycle) const;
|
|
|
|
bool operator()(SUnit* left, SUnit* right) const;
|
|
};
|
|
|
|
class RegReductionPQBase : public SchedulingPriorityQueue {
|
|
protected:
|
|
std::vector<SUnit*> Queue;
|
|
unsigned CurQueueId;
|
|
bool TracksRegPressure;
|
|
bool SrcOrder;
|
|
|
|
// SUnits - The SUnits for the current graph.
|
|
std::vector<SUnit> *SUnits;
|
|
|
|
MachineFunction &MF;
|
|
const TargetInstrInfo *TII;
|
|
const TargetRegisterInfo *TRI;
|
|
const TargetLowering *TLI;
|
|
ScheduleDAGRRList *scheduleDAG;
|
|
|
|
// SethiUllmanNumbers - The SethiUllman number for each node.
|
|
std::vector<unsigned> SethiUllmanNumbers;
|
|
|
|
/// RegPressure - Tracking current reg pressure per register class.
|
|
///
|
|
std::vector<unsigned> RegPressure;
|
|
|
|
/// RegLimit - Tracking the number of allocatable registers per register
|
|
/// class.
|
|
std::vector<unsigned> RegLimit;
|
|
|
|
public:
|
|
RegReductionPQBase(MachineFunction &mf,
|
|
bool hasReadyFilter,
|
|
bool tracksrp,
|
|
bool srcorder,
|
|
const TargetInstrInfo *tii,
|
|
const TargetRegisterInfo *tri,
|
|
const TargetLowering *tli)
|
|
: SchedulingPriorityQueue(hasReadyFilter),
|
|
CurQueueId(0), TracksRegPressure(tracksrp), SrcOrder(srcorder),
|
|
MF(mf), TII(tii), TRI(tri), TLI(tli), scheduleDAG(NULL) {
|
|
if (TracksRegPressure) {
|
|
unsigned NumRC = TRI->getNumRegClasses();
|
|
RegLimit.resize(NumRC);
|
|
RegPressure.resize(NumRC);
|
|
std::fill(RegLimit.begin(), RegLimit.end(), 0);
|
|
std::fill(RegPressure.begin(), RegPressure.end(), 0);
|
|
for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
|
|
E = TRI->regclass_end(); I != E; ++I)
|
|
RegLimit[(*I)->getID()] = tri->getRegPressureLimit(*I, MF);
|
|
}
|
|
}
|
|
|
|
void setScheduleDAG(ScheduleDAGRRList *scheduleDag) {
|
|
scheduleDAG = scheduleDag;
|
|
}
|
|
|
|
ScheduleHazardRecognizer* getHazardRec() {
|
|
return scheduleDAG->getHazardRec();
|
|
}
|
|
|
|
void initNodes(std::vector<SUnit> &sunits);
|
|
|
|
void addNode(const SUnit *SU);
|
|
|
|
void updateNode(const SUnit *SU);
|
|
|
|
void releaseState() {
|
|
SUnits = 0;
|
|
SethiUllmanNumbers.clear();
|
|
std::fill(RegPressure.begin(), RegPressure.end(), 0);
|
|
}
|
|
|
|
unsigned getNodePriority(const SUnit *SU) const;
|
|
|
|
unsigned getNodeOrdering(const SUnit *SU) const {
|
|
if (!SU->getNode()) return 0;
|
|
|
|
return SU->getNode()->getIROrder();
|
|
}
|
|
|
|
bool empty() const { return Queue.empty(); }
|
|
|
|
void push(SUnit *U) {
|
|
assert(!U->NodeQueueId && "Node in the queue already");
|
|
U->NodeQueueId = ++CurQueueId;
|
|
Queue.push_back(U);
|
|
}
|
|
|
|
void remove(SUnit *SU) {
|
|
assert(!Queue.empty() && "Queue is empty!");
|
|
assert(SU->NodeQueueId != 0 && "Not in queue!");
|
|
std::vector<SUnit *>::iterator I = std::find(Queue.begin(), Queue.end(),
|
|
SU);
|
|
if (I != prior(Queue.end()))
|
|
std::swap(*I, Queue.back());
|
|
Queue.pop_back();
|
|
SU->NodeQueueId = 0;
|
|
}
|
|
|
|
bool tracksRegPressure() const { return TracksRegPressure; }
|
|
|
|
void dumpRegPressure() const;
|
|
|
|
bool HighRegPressure(const SUnit *SU) const;
|
|
|
|
bool MayReduceRegPressure(SUnit *SU) const;
|
|
|
|
int RegPressureDiff(SUnit *SU, unsigned &LiveUses) const;
|
|
|
|
void scheduledNode(SUnit *SU);
|
|
|
|
void unscheduledNode(SUnit *SU);
|
|
|
|
protected:
|
|
bool canClobber(const SUnit *SU, const SUnit *Op);
|
|
void AddPseudoTwoAddrDeps();
|
|
void PrescheduleNodesWithMultipleUses();
|
|
void CalculateSethiUllmanNumbers();
|
|
};
|
|
|
|
template<class SF>
|
|
static SUnit *popFromQueueImpl(std::vector<SUnit*> &Q, SF &Picker) {
|
|
std::vector<SUnit *>::iterator Best = Q.begin();
|
|
for (std::vector<SUnit *>::iterator I = llvm::next(Q.begin()),
|
|
E = Q.end(); I != E; ++I)
|
|
if (Picker(*Best, *I))
|
|
Best = I;
|
|
SUnit *V = *Best;
|
|
if (Best != prior(Q.end()))
|
|
std::swap(*Best, Q.back());
|
|
Q.pop_back();
|
|
return V;
|
|
}
|
|
|
|
template<class SF>
|
|
SUnit *popFromQueue(std::vector<SUnit*> &Q, SF &Picker, ScheduleDAG *DAG) {
|
|
#ifndef NDEBUG
|
|
if (DAG->StressSched) {
|
|
reverse_sort<SF> RPicker(Picker);
|
|
return popFromQueueImpl(Q, RPicker);
|
|
}
|
|
#endif
|
|
(void)DAG;
|
|
return popFromQueueImpl(Q, Picker);
|
|
}
|
|
|
|
template<class SF>
|
|
class RegReductionPriorityQueue : public RegReductionPQBase {
|
|
SF Picker;
|
|
|
|
public:
|
|
RegReductionPriorityQueue(MachineFunction &mf,
|
|
bool tracksrp,
|
|
bool srcorder,
|
|
const TargetInstrInfo *tii,
|
|
const TargetRegisterInfo *tri,
|
|
const TargetLowering *tli)
|
|
: RegReductionPQBase(mf, SF::HasReadyFilter, tracksrp, srcorder,
|
|
tii, tri, tli),
|
|
Picker(this) {}
|
|
|
|
bool isBottomUp() const { return SF::IsBottomUp; }
|
|
|
|
bool isReady(SUnit *U) const {
|
|
return Picker.HasReadyFilter && Picker.isReady(U, getCurCycle());
|
|
}
|
|
|
|
SUnit *pop() {
|
|
if (Queue.empty()) return NULL;
|
|
|
|
SUnit *V = popFromQueue(Queue, Picker, scheduleDAG);
|
|
V->NodeQueueId = 0;
|
|
return V;
|
|
}
|
|
|
|
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
|
|
void dump(ScheduleDAG *DAG) const {
|
|
// Emulate pop() without clobbering NodeQueueIds.
|
|
std::vector<SUnit*> DumpQueue = Queue;
|
|
SF DumpPicker = Picker;
|
|
while (!DumpQueue.empty()) {
|
|
SUnit *SU = popFromQueue(DumpQueue, DumpPicker, scheduleDAG);
|
|
dbgs() << "Height " << SU->getHeight() << ": ";
|
|
SU->dump(DAG);
|
|
}
|
|
}
|
|
#endif
|
|
};
|
|
|
|
typedef RegReductionPriorityQueue<bu_ls_rr_sort>
|
|
BURegReductionPriorityQueue;
|
|
|
|
typedef RegReductionPriorityQueue<src_ls_rr_sort>
|
|
SrcRegReductionPriorityQueue;
|
|
|
|
typedef RegReductionPriorityQueue<hybrid_ls_rr_sort>
|
|
HybridBURRPriorityQueue;
|
|
|
|
typedef RegReductionPriorityQueue<ilp_ls_rr_sort>
|
|
ILPBURRPriorityQueue;
|
|
} // end anonymous namespace
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Static Node Priority for Register Pressure Reduction
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// Check for special nodes that bypass scheduling heuristics.
|
|
// Currently this pushes TokenFactor nodes down, but may be used for other
|
|
// pseudo-ops as well.
|
|
//
|
|
// Return -1 to schedule right above left, 1 for left above right.
|
|
// Return 0 if no bias exists.
|
|
static int checkSpecialNodes(const SUnit *left, const SUnit *right) {
|
|
bool LSchedLow = left->isScheduleLow;
|
|
bool RSchedLow = right->isScheduleLow;
|
|
if (LSchedLow != RSchedLow)
|
|
return LSchedLow < RSchedLow ? 1 : -1;
|
|
return 0;
|
|
}
|
|
|
|
/// CalcNodeSethiUllmanNumber - Compute Sethi Ullman number.
|
|
/// Smaller number is the higher priority.
|
|
static unsigned
|
|
CalcNodeSethiUllmanNumber(const SUnit *SU, std::vector<unsigned> &SUNumbers) {
|
|
unsigned &SethiUllmanNumber = SUNumbers[SU->NodeNum];
|
|
if (SethiUllmanNumber != 0)
|
|
return SethiUllmanNumber;
|
|
|
|
unsigned Extra = 0;
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue; // ignore chain preds
|
|
SUnit *PredSU = I->getSUnit();
|
|
unsigned PredSethiUllman = CalcNodeSethiUllmanNumber(PredSU, SUNumbers);
|
|
if (PredSethiUllman > SethiUllmanNumber) {
|
|
SethiUllmanNumber = PredSethiUllman;
|
|
Extra = 0;
|
|
} else if (PredSethiUllman == SethiUllmanNumber)
|
|
++Extra;
|
|
}
|
|
|
|
SethiUllmanNumber += Extra;
|
|
|
|
if (SethiUllmanNumber == 0)
|
|
SethiUllmanNumber = 1;
|
|
|
|
return SethiUllmanNumber;
|
|
}
|
|
|
|
/// CalculateSethiUllmanNumbers - Calculate Sethi-Ullman numbers of all
|
|
/// scheduling units.
|
|
void RegReductionPQBase::CalculateSethiUllmanNumbers() {
|
|
SethiUllmanNumbers.assign(SUnits->size(), 0);
|
|
|
|
for (unsigned i = 0, e = SUnits->size(); i != e; ++i)
|
|
CalcNodeSethiUllmanNumber(&(*SUnits)[i], SethiUllmanNumbers);
|
|
}
|
|
|
|
void RegReductionPQBase::addNode(const SUnit *SU) {
|
|
unsigned SUSize = SethiUllmanNumbers.size();
|
|
if (SUnits->size() > SUSize)
|
|
SethiUllmanNumbers.resize(SUSize*2, 0);
|
|
CalcNodeSethiUllmanNumber(SU, SethiUllmanNumbers);
|
|
}
|
|
|
|
void RegReductionPQBase::updateNode(const SUnit *SU) {
|
|
SethiUllmanNumbers[SU->NodeNum] = 0;
|
|
CalcNodeSethiUllmanNumber(SU, SethiUllmanNumbers);
|
|
}
|
|
|
|
// Lower priority means schedule further down. For bottom-up scheduling, lower
|
|
// priority SUs are scheduled before higher priority SUs.
|
|
unsigned RegReductionPQBase::getNodePriority(const SUnit *SU) const {
|
|
assert(SU->NodeNum < SethiUllmanNumbers.size());
|
|
unsigned Opc = SU->getNode() ? SU->getNode()->getOpcode() : 0;
|
|
if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
|
|
// CopyToReg should be close to its uses to facilitate coalescing and
|
|
// avoid spilling.
|
|
return 0;
|
|
if (Opc == TargetOpcode::EXTRACT_SUBREG ||
|
|
Opc == TargetOpcode::SUBREG_TO_REG ||
|
|
Opc == TargetOpcode::INSERT_SUBREG)
|
|
// EXTRACT_SUBREG, INSERT_SUBREG, and SUBREG_TO_REG nodes should be
|
|
// close to their uses to facilitate coalescing.
|
|
return 0;
|
|
if (SU->NumSuccs == 0 && SU->NumPreds != 0)
|
|
// If SU does not have a register use, i.e. it doesn't produce a value
|
|
// that would be consumed (e.g. store), then it terminates a chain of
|
|
// computation. Give it a large SethiUllman number so it will be
|
|
// scheduled right before its predecessors that it doesn't lengthen
|
|
// their live ranges.
|
|
return 0xffff;
|
|
if (SU->NumPreds == 0 && SU->NumSuccs != 0)
|
|
// If SU does not have a register def, schedule it close to its uses
|
|
// because it does not lengthen any live ranges.
|
|
return 0;
|
|
#if 1
|
|
return SethiUllmanNumbers[SU->NodeNum];
|
|
#else
|
|
unsigned Priority = SethiUllmanNumbers[SU->NodeNum];
|
|
if (SU->isCallOp) {
|
|
// FIXME: This assumes all of the defs are used as call operands.
|
|
int NP = (int)Priority - SU->getNode()->getNumValues();
|
|
return (NP > 0) ? NP : 0;
|
|
}
|
|
return Priority;
|
|
#endif
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Register Pressure Tracking
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
void RegReductionPQBase::dumpRegPressure() const {
|
|
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
|
|
for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
|
|
E = TRI->regclass_end(); I != E; ++I) {
|
|
const TargetRegisterClass *RC = *I;
|
|
unsigned Id = RC->getID();
|
|
unsigned RP = RegPressure[Id];
|
|
if (!RP) continue;
|
|
DEBUG(dbgs() << RC->getName() << ": " << RP << " / " << RegLimit[Id]
|
|
<< '\n');
|
|
}
|
|
#endif
|
|
}
|
|
|
|
bool RegReductionPQBase::HighRegPressure(const SUnit *SU) const {
|
|
if (!TLI)
|
|
return false;
|
|
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl())
|
|
continue;
|
|
SUnit *PredSU = I->getSUnit();
|
|
// NumRegDefsLeft is zero when enough uses of this node have been scheduled
|
|
// to cover the number of registers defined (they are all live).
|
|
if (PredSU->NumRegDefsLeft == 0) {
|
|
continue;
|
|
}
|
|
for (ScheduleDAGSDNodes::RegDefIter RegDefPos(PredSU, scheduleDAG);
|
|
RegDefPos.IsValid(); RegDefPos.Advance()) {
|
|
unsigned RCId, Cost;
|
|
GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost, MF);
|
|
|
|
if ((RegPressure[RCId] + Cost) >= RegLimit[RCId])
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool RegReductionPQBase::MayReduceRegPressure(SUnit *SU) const {
|
|
const SDNode *N = SU->getNode();
|
|
|
|
if (!N->isMachineOpcode() || !SU->NumSuccs)
|
|
return false;
|
|
|
|
unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
|
|
for (unsigned i = 0; i != NumDefs; ++i) {
|
|
MVT VT = N->getSimpleValueType(i);
|
|
if (!N->hasAnyUseOfValue(i))
|
|
continue;
|
|
unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
|
|
if (RegPressure[RCId] >= RegLimit[RCId])
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Compute the register pressure contribution by this instruction by count up
|
|
// for uses that are not live and down for defs. Only count register classes
|
|
// that are already under high pressure. As a side effect, compute the number of
|
|
// uses of registers that are already live.
|
|
//
|
|
// FIXME: This encompasses the logic in HighRegPressure and MayReduceRegPressure
|
|
// so could probably be factored.
|
|
int RegReductionPQBase::RegPressureDiff(SUnit *SU, unsigned &LiveUses) const {
|
|
LiveUses = 0;
|
|
int PDiff = 0;
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl())
|
|
continue;
|
|
SUnit *PredSU = I->getSUnit();
|
|
// NumRegDefsLeft is zero when enough uses of this node have been scheduled
|
|
// to cover the number of registers defined (they are all live).
|
|
if (PredSU->NumRegDefsLeft == 0) {
|
|
if (PredSU->getNode()->isMachineOpcode())
|
|
++LiveUses;
|
|
continue;
|
|
}
|
|
for (ScheduleDAGSDNodes::RegDefIter RegDefPos(PredSU, scheduleDAG);
|
|
RegDefPos.IsValid(); RegDefPos.Advance()) {
|
|
MVT VT = RegDefPos.GetValue();
|
|
unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
|
|
if (RegPressure[RCId] >= RegLimit[RCId])
|
|
++PDiff;
|
|
}
|
|
}
|
|
const SDNode *N = SU->getNode();
|
|
|
|
if (!N || !N->isMachineOpcode() || !SU->NumSuccs)
|
|
return PDiff;
|
|
|
|
unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
|
|
for (unsigned i = 0; i != NumDefs; ++i) {
|
|
MVT VT = N->getSimpleValueType(i);
|
|
if (!N->hasAnyUseOfValue(i))
|
|
continue;
|
|
unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
|
|
if (RegPressure[RCId] >= RegLimit[RCId])
|
|
--PDiff;
|
|
}
|
|
return PDiff;
|
|
}
|
|
|
|
void RegReductionPQBase::scheduledNode(SUnit *SU) {
|
|
if (!TracksRegPressure)
|
|
return;
|
|
|
|
if (!SU->getNode())
|
|
return;
|
|
|
|
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl())
|
|
continue;
|
|
SUnit *PredSU = I->getSUnit();
|
|
// NumRegDefsLeft is zero when enough uses of this node have been scheduled
|
|
// to cover the number of registers defined (they are all live).
|
|
if (PredSU->NumRegDefsLeft == 0) {
|
|
continue;
|
|
}
|
|
// FIXME: The ScheduleDAG currently loses information about which of a
|
|
// node's values is consumed by each dependence. Consequently, if the node
|
|
// defines multiple register classes, we don't know which to pressurize
|
|
// here. Instead the following loop consumes the register defs in an
|
|
// arbitrary order. At least it handles the common case of clustered loads
|
|
// to the same class. For precise liveness, each SDep needs to indicate the
|
|
// result number. But that tightly couples the ScheduleDAG with the
|
|
// SelectionDAG making updates tricky. A simpler hack would be to attach a
|
|
// value type or register class to SDep.
|
|
//
|
|
// The most important aspect of register tracking is balancing the increase
|
|
// here with the reduction further below. Note that this SU may use multiple
|
|
// defs in PredSU. The can't be determined here, but we've already
|
|
// compensated by reducing NumRegDefsLeft in PredSU during
|
|
// ScheduleDAGSDNodes::AddSchedEdges.
|
|
--PredSU->NumRegDefsLeft;
|
|
unsigned SkipRegDefs = PredSU->NumRegDefsLeft;
|
|
for (ScheduleDAGSDNodes::RegDefIter RegDefPos(PredSU, scheduleDAG);
|
|
RegDefPos.IsValid(); RegDefPos.Advance(), --SkipRegDefs) {
|
|
if (SkipRegDefs)
|
|
continue;
|
|
|
|
unsigned RCId, Cost;
|
|
GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost, MF);
|
|
RegPressure[RCId] += Cost;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// We should have this assert, but there may be dead SDNodes that never
|
|
// materialize as SUnits, so they don't appear to generate liveness.
|
|
//assert(SU->NumRegDefsLeft == 0 && "not all regdefs have scheduled uses");
|
|
int SkipRegDefs = (int)SU->NumRegDefsLeft;
|
|
for (ScheduleDAGSDNodes::RegDefIter RegDefPos(SU, scheduleDAG);
|
|
RegDefPos.IsValid(); RegDefPos.Advance(), --SkipRegDefs) {
|
|
if (SkipRegDefs > 0)
|
|
continue;
|
|
unsigned RCId, Cost;
|
|
GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost, MF);
|
|
if (RegPressure[RCId] < Cost) {
|
|
// Register pressure tracking is imprecise. This can happen. But we try
|
|
// hard not to let it happen because it likely results in poor scheduling.
|
|
DEBUG(dbgs() << " SU(" << SU->NodeNum << ") has too many regdefs\n");
|
|
RegPressure[RCId] = 0;
|
|
}
|
|
else {
|
|
RegPressure[RCId] -= Cost;
|
|
}
|
|
}
|
|
dumpRegPressure();
|
|
}
|
|
|
|
void RegReductionPQBase::unscheduledNode(SUnit *SU) {
|
|
if (!TracksRegPressure)
|
|
return;
|
|
|
|
const SDNode *N = SU->getNode();
|
|
if (!N) return;
|
|
|
|
if (!N->isMachineOpcode()) {
|
|
if (N->getOpcode() != ISD::CopyToReg)
|
|
return;
|
|
} else {
|
|
unsigned Opc = N->getMachineOpcode();
|
|
if (Opc == TargetOpcode::EXTRACT_SUBREG ||
|
|
Opc == TargetOpcode::INSERT_SUBREG ||
|
|
Opc == TargetOpcode::SUBREG_TO_REG ||
|
|
Opc == TargetOpcode::REG_SEQUENCE ||
|
|
Opc == TargetOpcode::IMPLICIT_DEF)
|
|
return;
|
|
}
|
|
|
|
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl())
|
|
continue;
|
|
SUnit *PredSU = I->getSUnit();
|
|
// NumSuccsLeft counts all deps. Don't compare it with NumSuccs which only
|
|
// counts data deps.
|
|
if (PredSU->NumSuccsLeft != PredSU->Succs.size())
|
|
continue;
|
|
const SDNode *PN = PredSU->getNode();
|
|
if (!PN->isMachineOpcode()) {
|
|
if (PN->getOpcode() == ISD::CopyFromReg) {
|
|
MVT VT = PN->getSimpleValueType(0);
|
|
unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
|
|
RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
|
|
}
|
|
continue;
|
|
}
|
|
unsigned POpc = PN->getMachineOpcode();
|
|
if (POpc == TargetOpcode::IMPLICIT_DEF)
|
|
continue;
|
|
if (POpc == TargetOpcode::EXTRACT_SUBREG ||
|
|
POpc == TargetOpcode::INSERT_SUBREG ||
|
|
POpc == TargetOpcode::SUBREG_TO_REG) {
|
|
MVT VT = PN->getSimpleValueType(0);
|
|
unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
|
|
RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
|
|
continue;
|
|
}
|
|
unsigned NumDefs = TII->get(PN->getMachineOpcode()).getNumDefs();
|
|
for (unsigned i = 0; i != NumDefs; ++i) {
|
|
MVT VT = PN->getSimpleValueType(i);
|
|
if (!PN->hasAnyUseOfValue(i))
|
|
continue;
|
|
unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
|
|
if (RegPressure[RCId] < TLI->getRepRegClassCostFor(VT))
|
|
// Register pressure tracking is imprecise. This can happen.
|
|
RegPressure[RCId] = 0;
|
|
else
|
|
RegPressure[RCId] -= TLI->getRepRegClassCostFor(VT);
|
|
}
|
|
}
|
|
|
|
// Check for isMachineOpcode() as PrescheduleNodesWithMultipleUses()
|
|
// may transfer data dependencies to CopyToReg.
|
|
if (SU->NumSuccs && N->isMachineOpcode()) {
|
|
unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
|
|
for (unsigned i = NumDefs, e = N->getNumValues(); i != e; ++i) {
|
|
MVT VT = N->getSimpleValueType(i);
|
|
if (VT == MVT::Glue || VT == MVT::Other)
|
|
continue;
|
|
if (!N->hasAnyUseOfValue(i))
|
|
continue;
|
|
unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
|
|
RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
|
|
}
|
|
}
|
|
|
|
dumpRegPressure();
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Dynamic Node Priority for Register Pressure Reduction
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
/// closestSucc - Returns the scheduled cycle of the successor which is
|
|
/// closest to the current cycle.
|
|
static unsigned closestSucc(const SUnit *SU) {
|
|
unsigned MaxHeight = 0;
|
|
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue; // ignore chain succs
|
|
unsigned Height = I->getSUnit()->getHeight();
|
|
// If there are bunch of CopyToRegs stacked up, they should be considered
|
|
// to be at the same position.
|
|
if (I->getSUnit()->getNode() &&
|
|
I->getSUnit()->getNode()->getOpcode() == ISD::CopyToReg)
|
|
Height = closestSucc(I->getSUnit())+1;
|
|
if (Height > MaxHeight)
|
|
MaxHeight = Height;
|
|
}
|
|
return MaxHeight;
|
|
}
|
|
|
|
/// calcMaxScratches - Returns an cost estimate of the worse case requirement
|
|
/// for scratch registers, i.e. number of data dependencies.
|
|
static unsigned calcMaxScratches(const SUnit *SU) {
|
|
unsigned Scratches = 0;
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue; // ignore chain preds
|
|
Scratches++;
|
|
}
|
|
return Scratches;
|
|
}
|
|
|
|
/// hasOnlyLiveInOpers - Return true if SU has only value predecessors that are
|
|
/// CopyFromReg from a virtual register.
|
|
static bool hasOnlyLiveInOpers(const SUnit *SU) {
|
|
bool RetVal = false;
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue;
|
|
const SUnit *PredSU = I->getSUnit();
|
|
if (PredSU->getNode() &&
|
|
PredSU->getNode()->getOpcode() == ISD::CopyFromReg) {
|
|
unsigned Reg =
|
|
cast<RegisterSDNode>(PredSU->getNode()->getOperand(1))->getReg();
|
|
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
|
|
RetVal = true;
|
|
continue;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
return RetVal;
|
|
}
|
|
|
|
/// hasOnlyLiveOutUses - Return true if SU has only value successors that are
|
|
/// CopyToReg to a virtual register. This SU def is probably a liveout and
|
|
/// it has no other use. It should be scheduled closer to the terminator.
|
|
static bool hasOnlyLiveOutUses(const SUnit *SU) {
|
|
bool RetVal = false;
|
|
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue;
|
|
const SUnit *SuccSU = I->getSUnit();
|
|
if (SuccSU->getNode() && SuccSU->getNode()->getOpcode() == ISD::CopyToReg) {
|
|
unsigned Reg =
|
|
cast<RegisterSDNode>(SuccSU->getNode()->getOperand(1))->getReg();
|
|
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
|
|
RetVal = true;
|
|
continue;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
return RetVal;
|
|
}
|
|
|
|
// Set isVRegCycle for a node with only live in opers and live out uses. Also
|
|
// set isVRegCycle for its CopyFromReg operands.
|
|
//
|
|
// This is only relevant for single-block loops, in which case the VRegCycle
|
|
// node is likely an induction variable in which the operand and target virtual
|
|
// registers should be coalesced (e.g. pre/post increment values). Setting the
|
|
// isVRegCycle flag helps the scheduler prioritize other uses of the same
|
|
// CopyFromReg so that this node becomes the virtual register "kill". This
|
|
// avoids interference between the values live in and out of the block and
|
|
// eliminates a copy inside the loop.
|
|
static void initVRegCycle(SUnit *SU) {
|
|
if (DisableSchedVRegCycle)
|
|
return;
|
|
|
|
if (!hasOnlyLiveInOpers(SU) || !hasOnlyLiveOutUses(SU))
|
|
return;
|
|
|
|
DEBUG(dbgs() << "VRegCycle: SU(" << SU->NodeNum << ")\n");
|
|
|
|
SU->isVRegCycle = true;
|
|
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue;
|
|
I->getSUnit()->isVRegCycle = true;
|
|
}
|
|
}
|
|
|
|
// After scheduling the definition of a VRegCycle, clear the isVRegCycle flag of
|
|
// CopyFromReg operands. We should no longer penalize other uses of this VReg.
|
|
static void resetVRegCycle(SUnit *SU) {
|
|
if (!SU->isVRegCycle)
|
|
return;
|
|
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue; // ignore chain preds
|
|
SUnit *PredSU = I->getSUnit();
|
|
if (PredSU->isVRegCycle) {
|
|
assert(PredSU->getNode()->getOpcode() == ISD::CopyFromReg &&
|
|
"VRegCycle def must be CopyFromReg");
|
|
I->getSUnit()->isVRegCycle = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Return true if this SUnit uses a CopyFromReg node marked as a VRegCycle. This
|
|
// means a node that defines the VRegCycle has not been scheduled yet.
|
|
static bool hasVRegCycleUse(const SUnit *SU) {
|
|
// If this SU also defines the VReg, don't hoist it as a "use".
|
|
if (SU->isVRegCycle)
|
|
return false;
|
|
|
|
for (SUnit::const_pred_iterator I = SU->Preds.begin(),E = SU->Preds.end();
|
|
I != E; ++I) {
|
|
if (I->isCtrl()) continue; // ignore chain preds
|
|
if (I->getSUnit()->isVRegCycle &&
|
|
I->getSUnit()->getNode()->getOpcode() == ISD::CopyFromReg) {
|
|
DEBUG(dbgs() << " VReg cycle use: SU (" << SU->NodeNum << ")\n");
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Check for either a dependence (latency) or resource (hazard) stall.
|
|
//
|
|
// Note: The ScheduleHazardRecognizer interface requires a non-const SU.
|
|
static bool BUHasStall(SUnit *SU, int Height, RegReductionPQBase *SPQ) {
|
|
if ((int)SPQ->getCurCycle() < Height) return true;
|
|
if (SPQ->getHazardRec()->getHazardType(SU, 0)
|
|
!= ScheduleHazardRecognizer::NoHazard)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
// Return -1 if left has higher priority, 1 if right has higher priority.
|
|
// Return 0 if latency-based priority is equivalent.
|
|
static int BUCompareLatency(SUnit *left, SUnit *right, bool checkPref,
|
|
RegReductionPQBase *SPQ) {
|
|
// Scheduling an instruction that uses a VReg whose postincrement has not yet
|
|
// been scheduled will induce a copy. Model this as an extra cycle of latency.
|
|
int LPenalty = hasVRegCycleUse(left) ? 1 : 0;
|
|
int RPenalty = hasVRegCycleUse(right) ? 1 : 0;
|
|
int LHeight = (int)left->getHeight() + LPenalty;
|
|
int RHeight = (int)right->getHeight() + RPenalty;
|
|
|
|
bool LStall = (!checkPref || left->SchedulingPref == Sched::ILP) &&
|
|
BUHasStall(left, LHeight, SPQ);
|
|
bool RStall = (!checkPref || right->SchedulingPref == Sched::ILP) &&
|
|
BUHasStall(right, RHeight, SPQ);
|
|
|
|
// If scheduling one of the node will cause a pipeline stall, delay it.
|
|
// If scheduling either one of the node will cause a pipeline stall, sort
|
|
// them according to their height.
|
|
if (LStall) {
|
|
if (!RStall)
|
|
return 1;
|
|
if (LHeight != RHeight)
|
|
return LHeight > RHeight ? 1 : -1;
|
|
} else if (RStall)
|
|
return -1;
|
|
|
|
// If either node is scheduling for latency, sort them by height/depth
|
|
// and latency.
|
|
if (!checkPref || (left->SchedulingPref == Sched::ILP ||
|
|
right->SchedulingPref == Sched::ILP)) {
|
|
// If neither instruction stalls (!LStall && !RStall) and HazardRecognizer
|
|
// is enabled, grouping instructions by cycle, then its height is already
|
|
// covered so only its depth matters. We also reach this point if both stall
|
|
// but have the same height.
|
|
if (!SPQ->getHazardRec()->isEnabled()) {
|
|
if (LHeight != RHeight)
|
|
return LHeight > RHeight ? 1 : -1;
|
|
}
|
|
int LDepth = left->getDepth() - LPenalty;
|
|
int RDepth = right->getDepth() - RPenalty;
|
|
if (LDepth != RDepth) {
|
|
DEBUG(dbgs() << " Comparing latency of SU (" << left->NodeNum
|
|
<< ") depth " << LDepth << " vs SU (" << right->NodeNum
|
|
<< ") depth " << RDepth << "\n");
|
|
return LDepth < RDepth ? 1 : -1;
|
|
}
|
|
if (left->Latency != right->Latency)
|
|
return left->Latency > right->Latency ? 1 : -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static bool BURRSort(SUnit *left, SUnit *right, RegReductionPQBase *SPQ) {
|
|
// Schedule physical register definitions close to their use. This is
|
|
// motivated by microarchitectures that can fuse cmp+jump macro-ops. But as
|
|
// long as shortening physreg live ranges is generally good, we can defer
|
|
// creating a subtarget hook.
|
|
if (!DisableSchedPhysRegJoin) {
|
|
bool LHasPhysReg = left->hasPhysRegDefs;
|
|
bool RHasPhysReg = right->hasPhysRegDefs;
|
|
if (LHasPhysReg != RHasPhysReg) {
|
|
#ifndef NDEBUG
|
|
static const char *const PhysRegMsg[] = { " has no physreg",
|
|
" defines a physreg" };
|
|
#endif
|
|
DEBUG(dbgs() << " SU (" << left->NodeNum << ") "
|
|
<< PhysRegMsg[LHasPhysReg] << " SU(" << right->NodeNum << ") "
|
|
<< PhysRegMsg[RHasPhysReg] << "\n");
|
|
return LHasPhysReg < RHasPhysReg;
|
|
}
|
|
}
|
|
|
|
// Prioritize by Sethi-Ulmann number and push CopyToReg nodes down.
|
|
unsigned LPriority = SPQ->getNodePriority(left);
|
|
unsigned RPriority = SPQ->getNodePriority(right);
|
|
|
|
// Be really careful about hoisting call operands above previous calls.
|
|
// Only allows it if it would reduce register pressure.
|
|
if (left->isCall && right->isCallOp) {
|
|
unsigned RNumVals = right->getNode()->getNumValues();
|
|
RPriority = (RPriority > RNumVals) ? (RPriority - RNumVals) : 0;
|
|
}
|
|
if (right->isCall && left->isCallOp) {
|
|
unsigned LNumVals = left->getNode()->getNumValues();
|
|
LPriority = (LPriority > LNumVals) ? (LPriority - LNumVals) : 0;
|
|
}
|
|
|
|
if (LPriority != RPriority)
|
|
return LPriority > RPriority;
|
|
|
|
// One or both of the nodes are calls and their sethi-ullman numbers are the
|
|
// same, then keep source order.
|
|
if (left->isCall || right->isCall) {
|
|
unsigned LOrder = SPQ->getNodeOrdering(left);
|
|
unsigned ROrder = SPQ->getNodeOrdering(right);
|
|
|
|
// Prefer an ordering where the lower the non-zero order number, the higher
|
|
// the preference.
|
|
if ((LOrder || ROrder) && LOrder != ROrder)
|
|
return LOrder != 0 && (LOrder < ROrder || ROrder == 0);
|
|
}
|
|
|
|
// Try schedule def + use closer when Sethi-Ullman numbers are the same.
|
|
// e.g.
|
|
// t1 = op t2, c1
|
|
// t3 = op t4, c2
|
|
//
|
|
// and the following instructions are both ready.
|
|
// t2 = op c3
|
|
// t4 = op c4
|
|
//
|
|
// Then schedule t2 = op first.
|
|
// i.e.
|
|
// t4 = op c4
|
|
// t2 = op c3
|
|
// t1 = op t2, c1
|
|
// t3 = op t4, c2
|
|
//
|
|
// This creates more short live intervals.
|
|
unsigned LDist = closestSucc(left);
|
|
unsigned RDist = closestSucc(right);
|
|
if (LDist != RDist)
|
|
return LDist < RDist;
|
|
|
|
// How many registers becomes live when the node is scheduled.
|
|
unsigned LScratch = calcMaxScratches(left);
|
|
unsigned RScratch = calcMaxScratches(right);
|
|
if (LScratch != RScratch)
|
|
return LScratch > RScratch;
|
|
|
|
// Comparing latency against a call makes little sense unless the node
|
|
// is register pressure-neutral.
|
|
if ((left->isCall && RPriority > 0) || (right->isCall && LPriority > 0))
|
|
return (left->NodeQueueId > right->NodeQueueId);
|
|
|
|
// Do not compare latencies when one or both of the nodes are calls.
|
|
if (!DisableSchedCycles &&
|
|
!(left->isCall || right->isCall)) {
|
|
int result = BUCompareLatency(left, right, false /*checkPref*/, SPQ);
|
|
if (result != 0)
|
|
return result > 0;
|
|
}
|
|
else {
|
|
if (left->getHeight() != right->getHeight())
|
|
return left->getHeight() > right->getHeight();
|
|
|
|
if (left->getDepth() != right->getDepth())
|
|
return left->getDepth() < right->getDepth();
|
|
}
|
|
|
|
assert(left->NodeQueueId && right->NodeQueueId &&
|
|
"NodeQueueId cannot be zero");
|
|
return (left->NodeQueueId > right->NodeQueueId);
|
|
}
|
|
|
|
// Bottom up
|
|
bool bu_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
|
|
if (int res = checkSpecialNodes(left, right))
|
|
return res > 0;
|
|
|
|
return BURRSort(left, right, SPQ);
|
|
}
|
|
|
|
// Source order, otherwise bottom up.
|
|
bool src_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
|
|
if (int res = checkSpecialNodes(left, right))
|
|
return res > 0;
|
|
|
|
unsigned LOrder = SPQ->getNodeOrdering(left);
|
|
unsigned ROrder = SPQ->getNodeOrdering(right);
|
|
|
|
// Prefer an ordering where the lower the non-zero order number, the higher
|
|
// the preference.
|
|
if ((LOrder || ROrder) && LOrder != ROrder)
|
|
return LOrder != 0 && (LOrder < ROrder || ROrder == 0);
|
|
|
|
return BURRSort(left, right, SPQ);
|
|
}
|
|
|
|
// If the time between now and when the instruction will be ready can cover
|
|
// the spill code, then avoid adding it to the ready queue. This gives long
|
|
// stalls highest priority and allows hoisting across calls. It should also
|
|
// speed up processing the available queue.
|
|
bool hybrid_ls_rr_sort::isReady(SUnit *SU, unsigned CurCycle) const {
|
|
static const unsigned ReadyDelay = 3;
|
|
|
|
if (SPQ->MayReduceRegPressure(SU)) return true;
|
|
|
|
if (SU->getHeight() > (CurCycle + ReadyDelay)) return false;
|
|
|
|
if (SPQ->getHazardRec()->getHazardType(SU, -ReadyDelay)
|
|
!= ScheduleHazardRecognizer::NoHazard)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
// Return true if right should be scheduled with higher priority than left.
|
|
bool hybrid_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
|
|
if (int res = checkSpecialNodes(left, right))
|
|
return res > 0;
|
|
|
|
if (left->isCall || right->isCall)
|
|
// No way to compute latency of calls.
|
|
return BURRSort(left, right, SPQ);
|
|
|
|
bool LHigh = SPQ->HighRegPressure(left);
|
|
bool RHigh = SPQ->HighRegPressure(right);
|
|
// Avoid causing spills. If register pressure is high, schedule for
|
|
// register pressure reduction.
|
|
if (LHigh && !RHigh) {
|
|
DEBUG(dbgs() << " pressure SU(" << left->NodeNum << ") > SU("
|
|
<< right->NodeNum << ")\n");
|
|
return true;
|
|
}
|
|
else if (!LHigh && RHigh) {
|
|
DEBUG(dbgs() << " pressure SU(" << right->NodeNum << ") > SU("
|
|
<< left->NodeNum << ")\n");
|
|
return false;
|
|
}
|
|
if (!LHigh && !RHigh) {
|
|
int result = BUCompareLatency(left, right, true /*checkPref*/, SPQ);
|
|
if (result != 0)
|
|
return result > 0;
|
|
}
|
|
return BURRSort(left, right, SPQ);
|
|
}
|
|
|
|
// Schedule as many instructions in each cycle as possible. So don't make an
|
|
// instruction available unless it is ready in the current cycle.
|
|
bool ilp_ls_rr_sort::isReady(SUnit *SU, unsigned CurCycle) const {
|
|
if (SU->getHeight() > CurCycle) return false;
|
|
|
|
if (SPQ->getHazardRec()->getHazardType(SU, 0)
|
|
!= ScheduleHazardRecognizer::NoHazard)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool canEnableCoalescing(SUnit *SU) {
|
|
unsigned Opc = SU->getNode() ? SU->getNode()->getOpcode() : 0;
|
|
if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
|
|
// CopyToReg should be close to its uses to facilitate coalescing and
|
|
// avoid spilling.
|
|
return true;
|
|
|
|
if (Opc == TargetOpcode::EXTRACT_SUBREG ||
|
|
Opc == TargetOpcode::SUBREG_TO_REG ||
|
|
Opc == TargetOpcode::INSERT_SUBREG)
|
|
// EXTRACT_SUBREG, INSERT_SUBREG, and SUBREG_TO_REG nodes should be
|
|
// close to their uses to facilitate coalescing.
|
|
return true;
|
|
|
|
if (SU->NumPreds == 0 && SU->NumSuccs != 0)
|
|
// If SU does not have a register def, schedule it close to its uses
|
|
// because it does not lengthen any live ranges.
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
// list-ilp is currently an experimental scheduler that allows various
|
|
// heuristics to be enabled prior to the normal register reduction logic.
|
|
bool ilp_ls_rr_sort::operator()(SUnit *left, SUnit *right) const {
|
|
if (int res = checkSpecialNodes(left, right))
|
|
return res > 0;
|
|
|
|
if (left->isCall || right->isCall)
|
|
// No way to compute latency of calls.
|
|
return BURRSort(left, right, SPQ);
|
|
|
|
unsigned LLiveUses = 0, RLiveUses = 0;
|
|
int LPDiff = 0, RPDiff = 0;
|
|
if (!DisableSchedRegPressure || !DisableSchedLiveUses) {
|
|
LPDiff = SPQ->RegPressureDiff(left, LLiveUses);
|
|
RPDiff = SPQ->RegPressureDiff(right, RLiveUses);
|
|
}
|
|
if (!DisableSchedRegPressure && LPDiff != RPDiff) {
|
|
DEBUG(dbgs() << "RegPressureDiff SU(" << left->NodeNum << "): " << LPDiff
|
|
<< " != SU(" << right->NodeNum << "): " << RPDiff << "\n");
|
|
return LPDiff > RPDiff;
|
|
}
|
|
|
|
if (!DisableSchedRegPressure && (LPDiff > 0 || RPDiff > 0)) {
|
|
bool LReduce = canEnableCoalescing(left);
|
|
bool RReduce = canEnableCoalescing(right);
|
|
if (LReduce && !RReduce) return false;
|
|
if (RReduce && !LReduce) return true;
|
|
}
|
|
|
|
if (!DisableSchedLiveUses && (LLiveUses != RLiveUses)) {
|
|
DEBUG(dbgs() << "Live uses SU(" << left->NodeNum << "): " << LLiveUses
|
|
<< " != SU(" << right->NodeNum << "): " << RLiveUses << "\n");
|
|
return LLiveUses < RLiveUses;
|
|
}
|
|
|
|
if (!DisableSchedStalls) {
|
|
bool LStall = BUHasStall(left, left->getHeight(), SPQ);
|
|
bool RStall = BUHasStall(right, right->getHeight(), SPQ);
|
|
if (LStall != RStall)
|
|
return left->getHeight() > right->getHeight();
|
|
}
|
|
|
|
if (!DisableSchedCriticalPath) {
|
|
int spread = (int)left->getDepth() - (int)right->getDepth();
|
|
if (std::abs(spread) > MaxReorderWindow) {
|
|
DEBUG(dbgs() << "Depth of SU(" << left->NodeNum << "): "
|
|
<< left->getDepth() << " != SU(" << right->NodeNum << "): "
|
|
<< right->getDepth() << "\n");
|
|
return left->getDepth() < right->getDepth();
|
|
}
|
|
}
|
|
|
|
if (!DisableSchedHeight && left->getHeight() != right->getHeight()) {
|
|
int spread = (int)left->getHeight() - (int)right->getHeight();
|
|
if (std::abs(spread) > MaxReorderWindow)
|
|
return left->getHeight() > right->getHeight();
|
|
}
|
|
|
|
return BURRSort(left, right, SPQ);
|
|
}
|
|
|
|
void RegReductionPQBase::initNodes(std::vector<SUnit> &sunits) {
|
|
SUnits = &sunits;
|
|
// Add pseudo dependency edges for two-address nodes.
|
|
if (!Disable2AddrHack)
|
|
AddPseudoTwoAddrDeps();
|
|
// Reroute edges to nodes with multiple uses.
|
|
if (!TracksRegPressure && !SrcOrder)
|
|
PrescheduleNodesWithMultipleUses();
|
|
// Calculate node priorities.
|
|
CalculateSethiUllmanNumbers();
|
|
|
|
// For single block loops, mark nodes that look like canonical IV increments.
|
|
if (scheduleDAG->BB->isSuccessor(scheduleDAG->BB)) {
|
|
for (unsigned i = 0, e = sunits.size(); i != e; ++i) {
|
|
initVRegCycle(&sunits[i]);
|
|
}
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Preschedule for Register Pressure
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
bool RegReductionPQBase::canClobber(const SUnit *SU, const SUnit *Op) {
|
|
if (SU->isTwoAddress) {
|
|
unsigned Opc = SU->getNode()->getMachineOpcode();
|
|
const MCInstrDesc &MCID = TII->get(Opc);
|
|
unsigned NumRes = MCID.getNumDefs();
|
|
unsigned NumOps = MCID.getNumOperands() - NumRes;
|
|
for (unsigned i = 0; i != NumOps; ++i) {
|
|
if (MCID.getOperandConstraint(i+NumRes, MCOI::TIED_TO) != -1) {
|
|
SDNode *DU = SU->getNode()->getOperand(i).getNode();
|
|
if (DU->getNodeId() != -1 &&
|
|
Op->OrigNode == &(*SUnits)[DU->getNodeId()])
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// canClobberReachingPhysRegUse - True if SU would clobber one of it's
|
|
/// successor's explicit physregs whose definition can reach DepSU.
|
|
/// i.e. DepSU should not be scheduled above SU.
|
|
static bool canClobberReachingPhysRegUse(const SUnit *DepSU, const SUnit *SU,
|
|
ScheduleDAGRRList *scheduleDAG,
|
|
const TargetInstrInfo *TII,
|
|
const TargetRegisterInfo *TRI) {
|
|
const uint16_t *ImpDefs
|
|
= TII->get(SU->getNode()->getMachineOpcode()).getImplicitDefs();
|
|
const uint32_t *RegMask = getNodeRegMask(SU->getNode());
|
|
if(!ImpDefs && !RegMask)
|
|
return false;
|
|
|
|
for (SUnit::const_succ_iterator SI = SU->Succs.begin(), SE = SU->Succs.end();
|
|
SI != SE; ++SI) {
|
|
SUnit *SuccSU = SI->getSUnit();
|
|
for (SUnit::const_pred_iterator PI = SuccSU->Preds.begin(),
|
|
PE = SuccSU->Preds.end(); PI != PE; ++PI) {
|
|
if (!PI->isAssignedRegDep())
|
|
continue;
|
|
|
|
if (RegMask && MachineOperand::clobbersPhysReg(RegMask, PI->getReg()) &&
|
|
scheduleDAG->IsReachable(DepSU, PI->getSUnit()))
|
|
return true;
|
|
|
|
if (ImpDefs)
|
|
for (const uint16_t *ImpDef = ImpDefs; *ImpDef; ++ImpDef)
|
|
// Return true if SU clobbers this physical register use and the
|
|
// definition of the register reaches from DepSU. IsReachable queries
|
|
// a topological forward sort of the DAG (following the successors).
|
|
if (TRI->regsOverlap(*ImpDef, PI->getReg()) &&
|
|
scheduleDAG->IsReachable(DepSU, PI->getSUnit()))
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// canClobberPhysRegDefs - True if SU would clobber one of SuccSU's
|
|
/// physical register defs.
|
|
static bool canClobberPhysRegDefs(const SUnit *SuccSU, const SUnit *SU,
|
|
const TargetInstrInfo *TII,
|
|
const TargetRegisterInfo *TRI) {
|
|
SDNode *N = SuccSU->getNode();
|
|
unsigned NumDefs = TII->get(N->getMachineOpcode()).getNumDefs();
|
|
const uint16_t *ImpDefs = TII->get(N->getMachineOpcode()).getImplicitDefs();
|
|
assert(ImpDefs && "Caller should check hasPhysRegDefs");
|
|
for (const SDNode *SUNode = SU->getNode(); SUNode;
|
|
SUNode = SUNode->getGluedNode()) {
|
|
if (!SUNode->isMachineOpcode())
|
|
continue;
|
|
const uint16_t *SUImpDefs =
|
|
TII->get(SUNode->getMachineOpcode()).getImplicitDefs();
|
|
const uint32_t *SURegMask = getNodeRegMask(SUNode);
|
|
if (!SUImpDefs && !SURegMask)
|
|
continue;
|
|
for (unsigned i = NumDefs, e = N->getNumValues(); i != e; ++i) {
|
|
EVT VT = N->getValueType(i);
|
|
if (VT == MVT::Glue || VT == MVT::Other)
|
|
continue;
|
|
if (!N->hasAnyUseOfValue(i))
|
|
continue;
|
|
unsigned Reg = ImpDefs[i - NumDefs];
|
|
if (SURegMask && MachineOperand::clobbersPhysReg(SURegMask, Reg))
|
|
return true;
|
|
if (!SUImpDefs)
|
|
continue;
|
|
for (;*SUImpDefs; ++SUImpDefs) {
|
|
unsigned SUReg = *SUImpDefs;
|
|
if (TRI->regsOverlap(Reg, SUReg))
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// PrescheduleNodesWithMultipleUses - Nodes with multiple uses
|
|
/// are not handled well by the general register pressure reduction
|
|
/// heuristics. When presented with code like this:
|
|
///
|
|
/// N
|
|
/// / |
|
|
/// / |
|
|
/// U store
|
|
/// |
|
|
/// ...
|
|
///
|
|
/// the heuristics tend to push the store up, but since the
|
|
/// operand of the store has another use (U), this would increase
|
|
/// the length of that other use (the U->N edge).
|
|
///
|
|
/// This function transforms code like the above to route U's
|
|
/// dependence through the store when possible, like this:
|
|
///
|
|
/// N
|
|
/// ||
|
|
/// ||
|
|
/// store
|
|
/// |
|
|
/// U
|
|
/// |
|
|
/// ...
|
|
///
|
|
/// This results in the store being scheduled immediately
|
|
/// after N, which shortens the U->N live range, reducing
|
|
/// register pressure.
|
|
///
|
|
void RegReductionPQBase::PrescheduleNodesWithMultipleUses() {
|
|
// Visit all the nodes in topological order, working top-down.
|
|
for (unsigned i = 0, e = SUnits->size(); i != e; ++i) {
|
|
SUnit *SU = &(*SUnits)[i];
|
|
// For now, only look at nodes with no data successors, such as stores.
|
|
// These are especially important, due to the heuristics in
|
|
// getNodePriority for nodes with no data successors.
|
|
if (SU->NumSuccs != 0)
|
|
continue;
|
|
// For now, only look at nodes with exactly one data predecessor.
|
|
if (SU->NumPreds != 1)
|
|
continue;
|
|
// Avoid prescheduling copies to virtual registers, which don't behave
|
|
// like other nodes from the perspective of scheduling heuristics.
|
|
if (SDNode *N = SU->getNode())
|
|
if (N->getOpcode() == ISD::CopyToReg &&
|
|
TargetRegisterInfo::isVirtualRegister
|
|
(cast<RegisterSDNode>(N->getOperand(1))->getReg()))
|
|
continue;
|
|
|
|
// Locate the single data predecessor.
|
|
SUnit *PredSU = 0;
|
|
for (SUnit::const_pred_iterator II = SU->Preds.begin(),
|
|
EE = SU->Preds.end(); II != EE; ++II)
|
|
if (!II->isCtrl()) {
|
|
PredSU = II->getSUnit();
|
|
break;
|
|
}
|
|
assert(PredSU);
|
|
|
|
// Don't rewrite edges that carry physregs, because that requires additional
|
|
// support infrastructure.
|
|
if (PredSU->hasPhysRegDefs)
|
|
continue;
|
|
// Short-circuit the case where SU is PredSU's only data successor.
|
|
if (PredSU->NumSuccs == 1)
|
|
continue;
|
|
// Avoid prescheduling to copies from virtual registers, which don't behave
|
|
// like other nodes from the perspective of scheduling heuristics.
|
|
if (SDNode *N = SU->getNode())
|
|
if (N->getOpcode() == ISD::CopyFromReg &&
|
|
TargetRegisterInfo::isVirtualRegister
|
|
(cast<RegisterSDNode>(N->getOperand(1))->getReg()))
|
|
continue;
|
|
|
|
// Perform checks on the successors of PredSU.
|
|
for (SUnit::const_succ_iterator II = PredSU->Succs.begin(),
|
|
EE = PredSU->Succs.end(); II != EE; ++II) {
|
|
SUnit *PredSuccSU = II->getSUnit();
|
|
if (PredSuccSU == SU) continue;
|
|
// If PredSU has another successor with no data successors, for
|
|
// now don't attempt to choose either over the other.
|
|
if (PredSuccSU->NumSuccs == 0)
|
|
goto outer_loop_continue;
|
|
// Don't break physical register dependencies.
|
|
if (SU->hasPhysRegClobbers && PredSuccSU->hasPhysRegDefs)
|
|
if (canClobberPhysRegDefs(PredSuccSU, SU, TII, TRI))
|
|
goto outer_loop_continue;
|
|
// Don't introduce graph cycles.
|
|
if (scheduleDAG->IsReachable(SU, PredSuccSU))
|
|
goto outer_loop_continue;
|
|
}
|
|
|
|
// Ok, the transformation is safe and the heuristics suggest it is
|
|
// profitable. Update the graph.
|
|
DEBUG(dbgs() << " Prescheduling SU #" << SU->NodeNum
|
|
<< " next to PredSU #" << PredSU->NodeNum
|
|
<< " to guide scheduling in the presence of multiple uses\n");
|
|
for (unsigned i = 0; i != PredSU->Succs.size(); ++i) {
|
|
SDep Edge = PredSU->Succs[i];
|
|
assert(!Edge.isAssignedRegDep());
|
|
SUnit *SuccSU = Edge.getSUnit();
|
|
if (SuccSU != SU) {
|
|
Edge.setSUnit(PredSU);
|
|
scheduleDAG->RemovePred(SuccSU, Edge);
|
|
scheduleDAG->AddPred(SU, Edge);
|
|
Edge.setSUnit(SU);
|
|
scheduleDAG->AddPred(SuccSU, Edge);
|
|
--i;
|
|
}
|
|
}
|
|
outer_loop_continue:;
|
|
}
|
|
}
|
|
|
|
/// AddPseudoTwoAddrDeps - If two nodes share an operand and one of them uses
|
|
/// it as a def&use operand. Add a pseudo control edge from it to the other
|
|
/// node (if it won't create a cycle) so the two-address one will be scheduled
|
|
/// first (lower in the schedule). If both nodes are two-address, favor the
|
|
/// one that has a CopyToReg use (more likely to be a loop induction update).
|
|
/// If both are two-address, but one is commutable while the other is not
|
|
/// commutable, favor the one that's not commutable.
|
|
void RegReductionPQBase::AddPseudoTwoAddrDeps() {
|
|
for (unsigned i = 0, e = SUnits->size(); i != e; ++i) {
|
|
SUnit *SU = &(*SUnits)[i];
|
|
if (!SU->isTwoAddress)
|
|
continue;
|
|
|
|
SDNode *Node = SU->getNode();
|
|
if (!Node || !Node->isMachineOpcode() || SU->getNode()->getGluedNode())
|
|
continue;
|
|
|
|
bool isLiveOut = hasOnlyLiveOutUses(SU);
|
|
unsigned Opc = Node->getMachineOpcode();
|
|
const MCInstrDesc &MCID = TII->get(Opc);
|
|
unsigned NumRes = MCID.getNumDefs();
|
|
unsigned NumOps = MCID.getNumOperands() - NumRes;
|
|
for (unsigned j = 0; j != NumOps; ++j) {
|
|
if (MCID.getOperandConstraint(j+NumRes, MCOI::TIED_TO) == -1)
|
|
continue;
|
|
SDNode *DU = SU->getNode()->getOperand(j).getNode();
|
|
if (DU->getNodeId() == -1)
|
|
continue;
|
|
const SUnit *DUSU = &(*SUnits)[DU->getNodeId()];
|
|
if (!DUSU) continue;
|
|
for (SUnit::const_succ_iterator I = DUSU->Succs.begin(),
|
|
E = DUSU->Succs.end(); I != E; ++I) {
|
|
if (I->isCtrl()) continue;
|
|
SUnit *SuccSU = I->getSUnit();
|
|
if (SuccSU == SU)
|
|
continue;
|
|
// Be conservative. Ignore if nodes aren't at roughly the same
|
|
// depth and height.
|
|
if (SuccSU->getHeight() < SU->getHeight() &&
|
|
(SU->getHeight() - SuccSU->getHeight()) > 1)
|
|
continue;
|
|
// Skip past COPY_TO_REGCLASS nodes, so that the pseudo edge
|
|
// constrains whatever is using the copy, instead of the copy
|
|
// itself. In the case that the copy is coalesced, this
|
|
// preserves the intent of the pseudo two-address heurietics.
|
|
while (SuccSU->Succs.size() == 1 &&
|
|
SuccSU->getNode()->isMachineOpcode() &&
|
|
SuccSU->getNode()->getMachineOpcode() ==
|
|
TargetOpcode::COPY_TO_REGCLASS)
|
|
SuccSU = SuccSU->Succs.front().getSUnit();
|
|
// Don't constrain non-instruction nodes.
|
|
if (!SuccSU->getNode() || !SuccSU->getNode()->isMachineOpcode())
|
|
continue;
|
|
// Don't constrain nodes with physical register defs if the
|
|
// predecessor can clobber them.
|
|
if (SuccSU->hasPhysRegDefs && SU->hasPhysRegClobbers) {
|
|
if (canClobberPhysRegDefs(SuccSU, SU, TII, TRI))
|
|
continue;
|
|
}
|
|
// Don't constrain EXTRACT_SUBREG, INSERT_SUBREG, and SUBREG_TO_REG;
|
|
// these may be coalesced away. We want them close to their uses.
|
|
unsigned SuccOpc = SuccSU->getNode()->getMachineOpcode();
|
|
if (SuccOpc == TargetOpcode::EXTRACT_SUBREG ||
|
|
SuccOpc == TargetOpcode::INSERT_SUBREG ||
|
|
SuccOpc == TargetOpcode::SUBREG_TO_REG)
|
|
continue;
|
|
if (!canClobberReachingPhysRegUse(SuccSU, SU, scheduleDAG, TII, TRI) &&
|
|
(!canClobber(SuccSU, DUSU) ||
|
|
(isLiveOut && !hasOnlyLiveOutUses(SuccSU)) ||
|
|
(!SU->isCommutable && SuccSU->isCommutable)) &&
|
|
!scheduleDAG->IsReachable(SuccSU, SU)) {
|
|
DEBUG(dbgs() << " Adding a pseudo-two-addr edge from SU #"
|
|
<< SU->NodeNum << " to SU #" << SuccSU->NodeNum << "\n");
|
|
scheduleDAG->AddPred(SU, SDep(SuccSU, SDep::Artificial));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Public Constructor Functions
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
llvm::ScheduleDAGSDNodes *
|
|
llvm::createBURRListDAGScheduler(SelectionDAGISel *IS,
|
|
CodeGenOpt::Level OptLevel) {
|
|
const TargetMachine &TM = IS->TM;
|
|
const TargetInstrInfo *TII = TM.getInstrInfo();
|
|
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
|
|
|
|
BURegReductionPriorityQueue *PQ =
|
|
new BURegReductionPriorityQueue(*IS->MF, false, false, TII, TRI, 0);
|
|
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, false, PQ, OptLevel);
|
|
PQ->setScheduleDAG(SD);
|
|
return SD;
|
|
}
|
|
|
|
llvm::ScheduleDAGSDNodes *
|
|
llvm::createSourceListDAGScheduler(SelectionDAGISel *IS,
|
|
CodeGenOpt::Level OptLevel) {
|
|
const TargetMachine &TM = IS->TM;
|
|
const TargetInstrInfo *TII = TM.getInstrInfo();
|
|
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
|
|
|
|
SrcRegReductionPriorityQueue *PQ =
|
|
new SrcRegReductionPriorityQueue(*IS->MF, false, true, TII, TRI, 0);
|
|
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, false, PQ, OptLevel);
|
|
PQ->setScheduleDAG(SD);
|
|
return SD;
|
|
}
|
|
|
|
llvm::ScheduleDAGSDNodes *
|
|
llvm::createHybridListDAGScheduler(SelectionDAGISel *IS,
|
|
CodeGenOpt::Level OptLevel) {
|
|
const TargetMachine &TM = IS->TM;
|
|
const TargetInstrInfo *TII = TM.getInstrInfo();
|
|
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
|
|
const TargetLowering *TLI = IS->getTargetLowering();
|
|
|
|
HybridBURRPriorityQueue *PQ =
|
|
new HybridBURRPriorityQueue(*IS->MF, true, false, TII, TRI, TLI);
|
|
|
|
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, true, PQ, OptLevel);
|
|
PQ->setScheduleDAG(SD);
|
|
return SD;
|
|
}
|
|
|
|
llvm::ScheduleDAGSDNodes *
|
|
llvm::createILPListDAGScheduler(SelectionDAGISel *IS,
|
|
CodeGenOpt::Level OptLevel) {
|
|
const TargetMachine &TM = IS->TM;
|
|
const TargetInstrInfo *TII = TM.getInstrInfo();
|
|
const TargetRegisterInfo *TRI = TM.getRegisterInfo();
|
|
const TargetLowering *TLI = IS->getTargetLowering();
|
|
|
|
ILPBURRPriorityQueue *PQ =
|
|
new ILPBURRPriorityQueue(*IS->MF, true, false, TII, TRI, TLI);
|
|
ScheduleDAGRRList *SD = new ScheduleDAGRRList(*IS->MF, true, PQ, OptLevel);
|
|
PQ->setScheduleDAG(SD);
|
|
return SD;
|
|
}
|