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[Hexagon] Use timing class info as tie-breaker in machine scheduler 

Patch by Sirish Pande.

llvm-svn: 275794
This commit is contained in:
Krzysztof Parzyszek 2016-07-18 15:17:10 +00:00
parent 3467e9d0a9
commit 393b37937b
2 changed files with 67 additions and 1 deletions
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66
llvm/lib/Target/Hexagon/HexagonMachineScheduler.cpp
View File

@ -24,6 +24,15 @@ static cl::opt<bool> IgnoreBBRegPressure("ignore-bb-reg-pressure",
static cl::opt<bool> SchedPredsCloser("sched-preds-closer",
cl::Hidden, cl::ZeroOrMore, cl::init(true));
static cl::opt<bool> TopUseShorterTie("top-use-shorter-tie",
cl::Hidden, cl::ZeroOrMore, cl::init(false));
static cl::opt<bool> BotUseShorterTie("bot-use-shorter-tie",
cl::Hidden, cl::ZeroOrMore, cl::init(false));
static cl::opt<bool> DisableTCTie("disable-tc-tie",
cl::Hidden, cl::ZeroOrMore, cl::init(false));
static cl::opt<bool> SchedRetvalOptimization("sched-retval-optimization",
cl::Hidden, cl::ZeroOrMore, cl::init(true));
@ -775,6 +784,55 @@ pickNodeFromQueue(ReadyQueue &Q, const RegPressureTracker &RPTracker,
continue;
}
// Tie breaker using Timing Class.
if (!DisableTCTie) {
auto &QST = DAG->MF.getSubtarget<HexagonSubtarget>();
auto &QII = *QST.getInstrInfo();
const MachineInstr *MI = (*I)->getInstr();
const MachineInstr *CandI = Candidate.SU->getInstr();
const InstrItineraryData *InstrItins = QST.getInstrItineraryData();
unsigned InstrLatency = QII.getInstrTimingClassLatency(InstrItins, MI);
unsigned CandLatency = QII.getInstrTimingClassLatency(InstrItins, CandI);
DEBUG(dbgs() << "TC Tie Breaker Cand: "
<< CandLatency << " Instr:" << InstrLatency << "\n"
<< *MI << *CandI << "\n");
if (Q.getID() == TopQID && CurrentCost == Candidate.SCost) {
if (InstrLatency < CandLatency && TopUseShorterTie) {
Candidate.SU = *I;
Candidate.RPDelta = RPDelta;
Candidate.SCost = CurrentCost;
FoundCandidate = BestCost;
DEBUG(dbgs() << "Used top shorter tie breaker\n");
continue;
} else if (InstrLatency > CandLatency && !TopUseShorterTie) {
Candidate.SU = *I;
Candidate.RPDelta = RPDelta;
Candidate.SCost = CurrentCost;
FoundCandidate = BestCost;
DEBUG(dbgs() << "Used top longer tie breaker\n");
continue;
}
} else if (Q.getID() == BotQID && CurrentCost == Candidate.SCost) {
if (InstrLatency < CandLatency && BotUseShorterTie) {
Candidate.SU = *I;
Candidate.RPDelta = RPDelta;
Candidate.SCost = CurrentCost;
FoundCandidate = BestCost;
DEBUG(dbgs() << "Used Bot shorter tie breaker\n");
continue;
} else if (InstrLatency > CandLatency && !BotUseShorterTie) {
Candidate.SU = *I;
Candidate.RPDelta = RPDelta;
Candidate.SCost = CurrentCost;
FoundCandidate = BestCost;
DEBUG(dbgs() << "Used Bot longer tie breaker\n");
continue;
}
}
}
if (CurrentCost == Candidate.SCost) {
if ((Q.getID() == TopQID &&
(*I)->Succs.size() > Candidate.SU->Succs.size()) ||
@ -802,10 +860,12 @@ SUnit *ConvergingVLIWScheduler::pickNodeBidrectional(bool &IsTopNode) {
// Schedule as far as possible in the direction of no choice. This is most
// efficient, but also provides the best heuristics for CriticalPSets.
if (SUnit *SU = Bot.pickOnlyChoice()) {
DEBUG(dbgs() << "Picked only Bottom\n");
IsTopNode = false;
return SU;
}
if (SUnit *SU = Top.pickOnlyChoice()) {
DEBUG(dbgs() << "Picked only Top\n");
IsTopNode = true;
return SU;
}
@ -823,6 +883,7 @@ SUnit *ConvergingVLIWScheduler::pickNodeBidrectional(bool &IsTopNode) {
// increase pressure for one of the excess PSets, then schedule in that
// direction first to provide more freedom in the other direction.
if (BotResult == SingleExcess || BotResult == SingleCritical) {
DEBUG(dbgs() << "Prefered Bottom Node\n");
IsTopNode = false;
return BotCand.SU;
}
@ -833,24 +894,29 @@ SUnit *ConvergingVLIWScheduler::pickNodeBidrectional(bool &IsTopNode) {
assert(TopResult != NoCand && "failed to find the first candidate");
if (TopResult == SingleExcess || TopResult == SingleCritical) {
DEBUG(dbgs() << "Prefered Top Node\n");
IsTopNode = true;
return TopCand.SU;
}
// If either Q has a single candidate that minimizes pressure above the
// original region's pressure pick it.
if (BotResult == SingleMax) {
DEBUG(dbgs() << "Prefered Bottom Node SingleMax\n");
IsTopNode = false;
return BotCand.SU;
}
if (TopResult == SingleMax) {
DEBUG(dbgs() << "Prefered Top Node SingleMax\n");
IsTopNode = true;
return TopCand.SU;
}
if (TopCand.SCost > BotCand.SCost) {
DEBUG(dbgs() << "Prefered Top Node Cost\n");
IsTopNode = true;
return TopCand.SU;
}
// Otherwise prefer the bottom candidate in node order.
DEBUG(dbgs() << "Prefered Bottom in Node order\n");
IsTopNode = false;
return BotCand.SU;
}

2
llvm/test/CodeGen/Hexagon/sube.ll
View File

@ -1,7 +1,7 @@
; RUN: llc -march=hexagon -disable-hsdr -hexagon-expand-condsets=0 -hexagon-bit=0 -disable-post-ra < %s | FileCheck %s
; CHECK: r{{[0-9]+:[0-9]+}} = combine(#0, #1)
; CHECK: r{{[0-9]+:[0-9]+}} = combine(#0, #0)
; CHECK: r{{[0-9]+:[0-9]+}} = combine(#0, #1)
; CHECK: p{{[0-9]+}} = cmp.gtu(r{{[0-9]+:[0-9]+}}, r{{[0-9]+:[0-9]+}})
; CHECK: r{{[0-9]+:[0-9]+}} = sub(r{{[0-9]+:[0-9]+}}, r{{[0-9]+:[0-9]+}})
; CHECK: r{{[0-9]+}} = mux(p{{[0-9]+}}, r{{[0-9]+}}, r{{[0-9]+}})