1 //===- GCNRegPressure.cpp -------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file implements the GCNRegPressure class.
11 ///
12 //===----------------------------------------------------------------------===//
13
14 #include "GCNRegPressure.h"
15 #include "AMDGPU.h"
16 #include "llvm/CodeGen/RegisterPressure.h"
17
18 using namespace llvm;
19
20 #define DEBUG_TYPE "machine-scheduler"
21
isEqual(const GCNRPTracker::LiveRegSet & S1,const GCNRPTracker::LiveRegSet & S2)22 bool llvm::isEqual(const GCNRPTracker::LiveRegSet &S1,
23 const GCNRPTracker::LiveRegSet &S2) {
24 if (S1.size() != S2.size())
25 return false;
26
27 for (const auto &P : S1) {
28 auto I = S2.find(P.first);
29 if (I == S2.end() || I->second != P.second)
30 return false;
31 }
32 return true;
33 }
34
35 ///////////////////////////////////////////////////////////////////////////////
36 // GCNRegPressure
37
getRegKind(Register Reg,const MachineRegisterInfo & MRI)38 unsigned GCNRegPressure::getRegKind(Register Reg,
39 const MachineRegisterInfo &MRI) {
40 assert(Reg.isVirtual());
41 const auto RC = MRI.getRegClass(Reg);
42 auto STI = static_cast<const SIRegisterInfo*>(MRI.getTargetRegisterInfo());
43 return STI->isSGPRClass(RC)
44 ? (STI->getRegSizeInBits(*RC) == 32 ? SGPR32 : SGPR_TUPLE)
45 : STI->isAGPRClass(RC)
46 ? (STI->getRegSizeInBits(*RC) == 32 ? AGPR32 : AGPR_TUPLE)
47 : (STI->getRegSizeInBits(*RC) == 32 ? VGPR32 : VGPR_TUPLE);
48 }
49
inc(unsigned Reg,LaneBitmask PrevMask,LaneBitmask NewMask,const MachineRegisterInfo & MRI)50 void GCNRegPressure::inc(unsigned Reg,
51 LaneBitmask PrevMask,
52 LaneBitmask NewMask,
53 const MachineRegisterInfo &MRI) {
54 if (SIRegisterInfo::getNumCoveredRegs(NewMask) ==
55 SIRegisterInfo::getNumCoveredRegs(PrevMask))
56 return;
57
58 int Sign = 1;
59 if (NewMask < PrevMask) {
60 std::swap(NewMask, PrevMask);
61 Sign = -1;
62 }
63
64 switch (auto Kind = getRegKind(Reg, MRI)) {
65 case SGPR32:
66 case VGPR32:
67 case AGPR32:
68 Value[Kind] += Sign;
69 break;
70
71 case SGPR_TUPLE:
72 case VGPR_TUPLE:
73 case AGPR_TUPLE:
74 assert(PrevMask < NewMask);
75
76 Value[Kind == SGPR_TUPLE ? SGPR32 : Kind == AGPR_TUPLE ? AGPR32 : VGPR32] +=
77 Sign * SIRegisterInfo::getNumCoveredRegs(~PrevMask & NewMask);
78
79 if (PrevMask.none()) {
80 assert(NewMask.any());
81 const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo();
82 Value[Kind] +=
83 Sign * TRI->getRegClassWeight(MRI.getRegClass(Reg)).RegWeight;
84 }
85 break;
86
87 default: llvm_unreachable("Unknown register kind");
88 }
89 }
90
less(const MachineFunction & MF,const GCNRegPressure & O,unsigned MaxOccupancy) const91 bool GCNRegPressure::less(const MachineFunction &MF, const GCNRegPressure &O,
92 unsigned MaxOccupancy) const {
93 const GCNSubtarget &ST = MF.getSubtarget<GCNSubtarget>();
94
95 const auto SGPROcc = std::min(MaxOccupancy,
96 ST.getOccupancyWithNumSGPRs(getSGPRNum()));
97 const auto VGPROcc =
98 std::min(MaxOccupancy,
99 ST.getOccupancyWithNumVGPRs(getVGPRNum(ST.hasGFX90AInsts())));
100 const auto OtherSGPROcc = std::min(MaxOccupancy,
101 ST.getOccupancyWithNumSGPRs(O.getSGPRNum()));
102 const auto OtherVGPROcc =
103 std::min(MaxOccupancy,
104 ST.getOccupancyWithNumVGPRs(O.getVGPRNum(ST.hasGFX90AInsts())));
105
106 const auto Occ = std::min(SGPROcc, VGPROcc);
107 const auto OtherOcc = std::min(OtherSGPROcc, OtherVGPROcc);
108
109 // Give first precedence to the better occupancy.
110 if (Occ != OtherOcc)
111 return Occ > OtherOcc;
112
113 unsigned MaxVGPRs = ST.getMaxNumVGPRs(MF);
114 unsigned MaxSGPRs = ST.getMaxNumSGPRs(MF);
115
116 // SGPR excess pressure conditions
117 unsigned ExcessSGPR = std::max(static_cast<int>(getSGPRNum() - MaxSGPRs), 0);
118 unsigned OtherExcessSGPR =
119 std::max(static_cast<int>(O.getSGPRNum() - MaxSGPRs), 0);
120
121 auto WaveSize = ST.getWavefrontSize();
122 // The number of virtual VGPRs required to handle excess SGPR
123 unsigned VGPRForSGPRSpills = (ExcessSGPR + (WaveSize - 1)) / WaveSize;
124 unsigned OtherVGPRForSGPRSpills =
125 (OtherExcessSGPR + (WaveSize - 1)) / WaveSize;
126
127 unsigned MaxArchVGPRs = ST.getAddressableNumArchVGPRs();
128
129 // Unified excess pressure conditions, accounting for VGPRs used for SGPR
130 // spills
131 unsigned ExcessVGPR =
132 std::max(static_cast<int>(getVGPRNum(ST.hasGFX90AInsts()) +
133 VGPRForSGPRSpills - MaxVGPRs),
134 0);
135 unsigned OtherExcessVGPR =
136 std::max(static_cast<int>(O.getVGPRNum(ST.hasGFX90AInsts()) +
137 OtherVGPRForSGPRSpills - MaxVGPRs),
138 0);
139 // Arch VGPR excess pressure conditions, accounting for VGPRs used for SGPR
140 // spills
141 unsigned ExcessArchVGPR = std::max(
142 static_cast<int>(getVGPRNum(false) + VGPRForSGPRSpills - MaxArchVGPRs),
143 0);
144 unsigned OtherExcessArchVGPR =
145 std::max(static_cast<int>(O.getVGPRNum(false) + OtherVGPRForSGPRSpills -
146 MaxArchVGPRs),
147 0);
148 // AGPR excess pressure conditions
149 unsigned ExcessAGPR = std::max(
150 static_cast<int>(ST.hasGFX90AInsts() ? (getAGPRNum() - MaxArchVGPRs)
151 : (getAGPRNum() - MaxVGPRs)),
152 0);
153 unsigned OtherExcessAGPR = std::max(
154 static_cast<int>(ST.hasGFX90AInsts() ? (O.getAGPRNum() - MaxArchVGPRs)
155 : (O.getAGPRNum() - MaxVGPRs)),
156 0);
157
158 bool ExcessRP = ExcessSGPR || ExcessVGPR || ExcessArchVGPR || ExcessAGPR;
159 bool OtherExcessRP = OtherExcessSGPR || OtherExcessVGPR ||
160 OtherExcessArchVGPR || OtherExcessAGPR;
161
162 // Give second precedence to the reduced number of spills to hold the register
163 // pressure.
164 if (ExcessRP || OtherExcessRP) {
165 // The difference in excess VGPR pressure, after including VGPRs used for
166 // SGPR spills
167 int VGPRDiff = ((OtherExcessVGPR + OtherExcessArchVGPR + OtherExcessAGPR) -
168 (ExcessVGPR + ExcessArchVGPR + ExcessAGPR));
169
170 int SGPRDiff = OtherExcessSGPR - ExcessSGPR;
171
172 if (VGPRDiff != 0)
173 return VGPRDiff > 0;
174 if (SGPRDiff != 0) {
175 unsigned PureExcessVGPR =
176 std::max(static_cast<int>(getVGPRNum(ST.hasGFX90AInsts()) - MaxVGPRs),
177 0) +
178 std::max(static_cast<int>(getVGPRNum(false) - MaxArchVGPRs), 0);
179 unsigned OtherPureExcessVGPR =
180 std::max(
181 static_cast<int>(O.getVGPRNum(ST.hasGFX90AInsts()) - MaxVGPRs),
182 0) +
183 std::max(static_cast<int>(O.getVGPRNum(false) - MaxArchVGPRs), 0);
184
185 // If we have a special case where there is a tie in excess VGPR, but one
186 // of the pressures has VGPR usage from SGPR spills, prefer the pressure
187 // with SGPR spills.
188 if (PureExcessVGPR != OtherPureExcessVGPR)
189 return SGPRDiff < 0;
190 // If both pressures have the same excess pressure before and after
191 // accounting for SGPR spills, prefer fewer SGPR spills.
192 return SGPRDiff > 0;
193 }
194 }
195
196 bool SGPRImportant = SGPROcc < VGPROcc;
197 const bool OtherSGPRImportant = OtherSGPROcc < OtherVGPROcc;
198
199 // If both pressures disagree on what is more important compare vgprs.
200 if (SGPRImportant != OtherSGPRImportant) {
201 SGPRImportant = false;
202 }
203
204 // Give third precedence to lower register tuple pressure.
205 bool SGPRFirst = SGPRImportant;
206 for (int I = 2; I > 0; --I, SGPRFirst = !SGPRFirst) {
207 if (SGPRFirst) {
208 auto SW = getSGPRTuplesWeight();
209 auto OtherSW = O.getSGPRTuplesWeight();
210 if (SW != OtherSW)
211 return SW < OtherSW;
212 } else {
213 auto VW = getVGPRTuplesWeight();
214 auto OtherVW = O.getVGPRTuplesWeight();
215 if (VW != OtherVW)
216 return VW < OtherVW;
217 }
218 }
219
220 // Give final precedence to lower general RP.
221 return SGPRImportant ? (getSGPRNum() < O.getSGPRNum()):
222 (getVGPRNum(ST.hasGFX90AInsts()) <
223 O.getVGPRNum(ST.hasGFX90AInsts()));
224 }
225
print(const GCNRegPressure & RP,const GCNSubtarget * ST)226 Printable llvm::print(const GCNRegPressure &RP, const GCNSubtarget *ST) {
227 return Printable([&RP, ST](raw_ostream &OS) {
228 OS << "VGPRs: " << RP.Value[GCNRegPressure::VGPR32] << ' '
229 << "AGPRs: " << RP.getAGPRNum();
230 if (ST)
231 OS << "(O"
232 << ST->getOccupancyWithNumVGPRs(RP.getVGPRNum(ST->hasGFX90AInsts()))
233 << ')';
234 OS << ", SGPRs: " << RP.getSGPRNum();
235 if (ST)
236 OS << "(O" << ST->getOccupancyWithNumSGPRs(RP.getSGPRNum()) << ')';
237 OS << ", LVGPR WT: " << RP.getVGPRTuplesWeight()
238 << ", LSGPR WT: " << RP.getSGPRTuplesWeight();
239 if (ST)
240 OS << " -> Occ: " << RP.getOccupancy(*ST);
241 OS << '\n';
242 });
243 }
244
getDefRegMask(const MachineOperand & MO,const MachineRegisterInfo & MRI)245 static LaneBitmask getDefRegMask(const MachineOperand &MO,
246 const MachineRegisterInfo &MRI) {
247 assert(MO.isDef() && MO.isReg() && MO.getReg().isVirtual());
248
249 // We don't rely on read-undef flag because in case of tentative schedule
250 // tracking it isn't set correctly yet. This works correctly however since
251 // use mask has been tracked before using LIS.
252 return MO.getSubReg() == 0 ?
253 MRI.getMaxLaneMaskForVReg(MO.getReg()) :
254 MRI.getTargetRegisterInfo()->getSubRegIndexLaneMask(MO.getSubReg());
255 }
256
257 static void
collectVirtualRegUses(SmallVectorImpl<RegisterMaskPair> & RegMaskPairs,const MachineInstr & MI,const LiveIntervals & LIS,const MachineRegisterInfo & MRI)258 collectVirtualRegUses(SmallVectorImpl<RegisterMaskPair> &RegMaskPairs,
259 const MachineInstr &MI, const LiveIntervals &LIS,
260 const MachineRegisterInfo &MRI) {
261 SlotIndex InstrSI;
262 for (const auto &MO : MI.operands()) {
263 if (!MO.isReg() || !MO.getReg().isVirtual())
264 continue;
265 if (!MO.isUse() || !MO.readsReg())
266 continue;
267
268 Register Reg = MO.getReg();
269 if (llvm::any_of(RegMaskPairs, [Reg](const RegisterMaskPair &RM) {
270 return RM.RegUnit == Reg;
271 }))
272 continue;
273
274 LaneBitmask UseMask;
275 auto &LI = LIS.getInterval(Reg);
276 if (!LI.hasSubRanges())
277 UseMask = MRI.getMaxLaneMaskForVReg(Reg);
278 else {
279 // For a tentative schedule LIS isn't updated yet but livemask should
280 // remain the same on any schedule. Subreg defs can be reordered but they
281 // all must dominate uses anyway.
282 if (!InstrSI)
283 InstrSI = LIS.getInstructionIndex(*MO.getParent()).getBaseIndex();
284 UseMask = getLiveLaneMask(LI, InstrSI, MRI);
285 }
286
287 RegMaskPairs.emplace_back(Reg, UseMask);
288 }
289 }
290
291 ///////////////////////////////////////////////////////////////////////////////
292 // GCNRPTracker
293
getLiveLaneMask(unsigned Reg,SlotIndex SI,const LiveIntervals & LIS,const MachineRegisterInfo & MRI)294 LaneBitmask llvm::getLiveLaneMask(unsigned Reg, SlotIndex SI,
295 const LiveIntervals &LIS,
296 const MachineRegisterInfo &MRI) {
297 return getLiveLaneMask(LIS.getInterval(Reg), SI, MRI);
298 }
299
getLiveLaneMask(const LiveInterval & LI,SlotIndex SI,const MachineRegisterInfo & MRI)300 LaneBitmask llvm::getLiveLaneMask(const LiveInterval &LI, SlotIndex SI,
301 const MachineRegisterInfo &MRI) {
302 LaneBitmask LiveMask;
303 if (LI.hasSubRanges()) {
304 for (const auto &S : LI.subranges())
305 if (S.liveAt(SI)) {
306 LiveMask |= S.LaneMask;
307 assert(LiveMask == (LiveMask & MRI.getMaxLaneMaskForVReg(LI.reg())));
308 }
309 } else if (LI.liveAt(SI)) {
310 LiveMask = MRI.getMaxLaneMaskForVReg(LI.reg());
311 }
312 return LiveMask;
313 }
314
getLiveRegs(SlotIndex SI,const LiveIntervals & LIS,const MachineRegisterInfo & MRI)315 GCNRPTracker::LiveRegSet llvm::getLiveRegs(SlotIndex SI,
316 const LiveIntervals &LIS,
317 const MachineRegisterInfo &MRI) {
318 GCNRPTracker::LiveRegSet LiveRegs;
319 for (unsigned I = 0, E = MRI.getNumVirtRegs(); I != E; ++I) {
320 auto Reg = Register::index2VirtReg(I);
321 if (!LIS.hasInterval(Reg))
322 continue;
323 auto LiveMask = getLiveLaneMask(Reg, SI, LIS, MRI);
324 if (LiveMask.any())
325 LiveRegs[Reg] = LiveMask;
326 }
327 return LiveRegs;
328 }
329
reset(const MachineInstr & MI,const LiveRegSet * LiveRegsCopy,bool After)330 void GCNRPTracker::reset(const MachineInstr &MI,
331 const LiveRegSet *LiveRegsCopy,
332 bool After) {
333 const MachineFunction &MF = *MI.getMF();
334 MRI = &MF.getRegInfo();
335 if (LiveRegsCopy) {
336 if (&LiveRegs != LiveRegsCopy)
337 LiveRegs = *LiveRegsCopy;
338 } else {
339 LiveRegs = After ? getLiveRegsAfter(MI, LIS)
340 : getLiveRegsBefore(MI, LIS);
341 }
342
343 MaxPressure = CurPressure = getRegPressure(*MRI, LiveRegs);
344 }
345
346 ////////////////////////////////////////////////////////////////////////////////
347 // GCNUpwardRPTracker
348
reset(const MachineRegisterInfo & MRI_,const LiveRegSet & LiveRegs_)349 void GCNUpwardRPTracker::reset(const MachineRegisterInfo &MRI_,
350 const LiveRegSet &LiveRegs_) {
351 MRI = &MRI_;
352 LiveRegs = LiveRegs_;
353 LastTrackedMI = nullptr;
354 MaxPressure = CurPressure = getRegPressure(MRI_, LiveRegs_);
355 }
356
recede(const MachineInstr & MI)357 void GCNUpwardRPTracker::recede(const MachineInstr &MI) {
358 assert(MRI && "call reset first");
359
360 LastTrackedMI = &MI;
361
362 if (MI.isDebugInstr())
363 return;
364
365 // Kill all defs.
366 GCNRegPressure DefPressure, ECDefPressure;
367 bool HasECDefs = false;
368 for (const MachineOperand &MO : MI.all_defs()) {
369 if (!MO.getReg().isVirtual())
370 continue;
371
372 Register Reg = MO.getReg();
373 LaneBitmask DefMask = getDefRegMask(MO, *MRI);
374
375 // Treat a def as fully live at the moment of definition: keep a record.
376 if (MO.isEarlyClobber()) {
377 ECDefPressure.inc(Reg, LaneBitmask::getNone(), DefMask, *MRI);
378 HasECDefs = true;
379 } else
380 DefPressure.inc(Reg, LaneBitmask::getNone(), DefMask, *MRI);
381
382 auto I = LiveRegs.find(Reg);
383 if (I == LiveRegs.end())
384 continue;
385
386 LaneBitmask &LiveMask = I->second;
387 LaneBitmask PrevMask = LiveMask;
388 LiveMask &= ~DefMask;
389 CurPressure.inc(Reg, PrevMask, LiveMask, *MRI);
390 if (LiveMask.none())
391 LiveRegs.erase(I);
392 }
393
394 // Update MaxPressure with defs pressure.
395 DefPressure += CurPressure;
396 if (HasECDefs)
397 DefPressure += ECDefPressure;
398 MaxPressure = max(DefPressure, MaxPressure);
399
400 // Make uses alive.
401 SmallVector<RegisterMaskPair, 8> RegUses;
402 collectVirtualRegUses(RegUses, MI, LIS, *MRI);
403 for (const RegisterMaskPair &U : RegUses) {
404 LaneBitmask &LiveMask = LiveRegs[U.RegUnit];
405 LaneBitmask PrevMask = LiveMask;
406 LiveMask |= U.LaneMask;
407 CurPressure.inc(U.RegUnit, PrevMask, LiveMask, *MRI);
408 }
409
410 // Update MaxPressure with uses plus early-clobber defs pressure.
411 MaxPressure = HasECDefs ? max(CurPressure + ECDefPressure, MaxPressure)
412 : max(CurPressure, MaxPressure);
413
414 assert(CurPressure == getRegPressure(*MRI, LiveRegs));
415 }
416
417 ////////////////////////////////////////////////////////////////////////////////
418 // GCNDownwardRPTracker
419
reset(const MachineInstr & MI,const LiveRegSet * LiveRegsCopy)420 bool GCNDownwardRPTracker::reset(const MachineInstr &MI,
421 const LiveRegSet *LiveRegsCopy) {
422 MRI = &MI.getParent()->getParent()->getRegInfo();
423 LastTrackedMI = nullptr;
424 MBBEnd = MI.getParent()->end();
425 NextMI = &MI;
426 NextMI = skipDebugInstructionsForward(NextMI, MBBEnd);
427 if (NextMI == MBBEnd)
428 return false;
429 GCNRPTracker::reset(*NextMI, LiveRegsCopy, false);
430 return true;
431 }
432
advanceBeforeNext()433 bool GCNDownwardRPTracker::advanceBeforeNext() {
434 assert(MRI && "call reset first");
435 if (!LastTrackedMI)
436 return NextMI == MBBEnd;
437
438 assert(NextMI == MBBEnd || !NextMI->isDebugInstr());
439
440 SlotIndex SI = NextMI == MBBEnd
441 ? LIS.getInstructionIndex(*LastTrackedMI).getDeadSlot()
442 : LIS.getInstructionIndex(*NextMI).getBaseIndex();
443 assert(SI.isValid());
444
445 // Remove dead registers or mask bits.
446 SmallSet<Register, 8> SeenRegs;
447 for (auto &MO : LastTrackedMI->operands()) {
448 if (!MO.isReg() || !MO.getReg().isVirtual())
449 continue;
450 if (MO.isUse() && !MO.readsReg())
451 continue;
452 if (!SeenRegs.insert(MO.getReg()).second)
453 continue;
454 const LiveInterval &LI = LIS.getInterval(MO.getReg());
455 if (LI.hasSubRanges()) {
456 auto It = LiveRegs.end();
457 for (const auto &S : LI.subranges()) {
458 if (!S.liveAt(SI)) {
459 if (It == LiveRegs.end()) {
460 It = LiveRegs.find(MO.getReg());
461 if (It == LiveRegs.end())
462 llvm_unreachable("register isn't live");
463 }
464 auto PrevMask = It->second;
465 It->second &= ~S.LaneMask;
466 CurPressure.inc(MO.getReg(), PrevMask, It->second, *MRI);
467 }
468 }
469 if (It != LiveRegs.end() && It->second.none())
470 LiveRegs.erase(It);
471 } else if (!LI.liveAt(SI)) {
472 auto It = LiveRegs.find(MO.getReg());
473 if (It == LiveRegs.end())
474 llvm_unreachable("register isn't live");
475 CurPressure.inc(MO.getReg(), It->second, LaneBitmask::getNone(), *MRI);
476 LiveRegs.erase(It);
477 }
478 }
479
480 MaxPressure = max(MaxPressure, CurPressure);
481
482 LastTrackedMI = nullptr;
483
484 return NextMI == MBBEnd;
485 }
486
advanceToNext()487 void GCNDownwardRPTracker::advanceToNext() {
488 LastTrackedMI = &*NextMI++;
489 NextMI = skipDebugInstructionsForward(NextMI, MBBEnd);
490
491 // Add new registers or mask bits.
492 for (const auto &MO : LastTrackedMI->all_defs()) {
493 Register Reg = MO.getReg();
494 if (!Reg.isVirtual())
495 continue;
496 auto &LiveMask = LiveRegs[Reg];
497 auto PrevMask = LiveMask;
498 LiveMask |= getDefRegMask(MO, *MRI);
499 CurPressure.inc(Reg, PrevMask, LiveMask, *MRI);
500 }
501
502 MaxPressure = max(MaxPressure, CurPressure);
503 }
504
advance()505 bool GCNDownwardRPTracker::advance() {
506 if (NextMI == MBBEnd)
507 return false;
508 advanceBeforeNext();
509 advanceToNext();
510 return true;
511 }
512
advance(MachineBasicBlock::const_iterator End)513 bool GCNDownwardRPTracker::advance(MachineBasicBlock::const_iterator End) {
514 while (NextMI != End)
515 if (!advance()) return false;
516 return true;
517 }
518
advance(MachineBasicBlock::const_iterator Begin,MachineBasicBlock::const_iterator End,const LiveRegSet * LiveRegsCopy)519 bool GCNDownwardRPTracker::advance(MachineBasicBlock::const_iterator Begin,
520 MachineBasicBlock::const_iterator End,
521 const LiveRegSet *LiveRegsCopy) {
522 reset(*Begin, LiveRegsCopy);
523 return advance(End);
524 }
525
reportMismatch(const GCNRPTracker::LiveRegSet & LISLR,const GCNRPTracker::LiveRegSet & TrackedLR,const TargetRegisterInfo * TRI,StringRef Pfx)526 Printable llvm::reportMismatch(const GCNRPTracker::LiveRegSet &LISLR,
527 const GCNRPTracker::LiveRegSet &TrackedLR,
528 const TargetRegisterInfo *TRI, StringRef Pfx) {
529 return Printable([&LISLR, &TrackedLR, TRI, Pfx](raw_ostream &OS) {
530 for (auto const &P : TrackedLR) {
531 auto I = LISLR.find(P.first);
532 if (I == LISLR.end()) {
533 OS << Pfx << printReg(P.first, TRI) << ":L" << PrintLaneMask(P.second)
534 << " isn't found in LIS reported set\n";
535 } else if (I->second != P.second) {
536 OS << Pfx << printReg(P.first, TRI)
537 << " masks doesn't match: LIS reported " << PrintLaneMask(I->second)
538 << ", tracked " << PrintLaneMask(P.second) << '\n';
539 }
540 }
541 for (auto const &P : LISLR) {
542 auto I = TrackedLR.find(P.first);
543 if (I == TrackedLR.end()) {
544 OS << Pfx << printReg(P.first, TRI) << ":L" << PrintLaneMask(P.second)
545 << " isn't found in tracked set\n";
546 }
547 }
548 });
549 }
550
isValid() const551 bool GCNUpwardRPTracker::isValid() const {
552 const auto &SI = LIS.getInstructionIndex(*LastTrackedMI).getBaseIndex();
553 const auto LISLR = llvm::getLiveRegs(SI, LIS, *MRI);
554 const auto &TrackedLR = LiveRegs;
555
556 if (!isEqual(LISLR, TrackedLR)) {
557 dbgs() << "\nGCNUpwardRPTracker error: Tracked and"
558 " LIS reported livesets mismatch:\n"
559 << print(LISLR, *MRI);
560 reportMismatch(LISLR, TrackedLR, MRI->getTargetRegisterInfo());
561 return false;
562 }
563
564 auto LISPressure = getRegPressure(*MRI, LISLR);
565 if (LISPressure != CurPressure) {
566 dbgs() << "GCNUpwardRPTracker error: Pressure sets different\nTracked: "
567 << print(CurPressure) << "LIS rpt: " << print(LISPressure);
568 return false;
569 }
570 return true;
571 }
572
print(const GCNRPTracker::LiveRegSet & LiveRegs,const MachineRegisterInfo & MRI)573 Printable llvm::print(const GCNRPTracker::LiveRegSet &LiveRegs,
574 const MachineRegisterInfo &MRI) {
575 return Printable([&LiveRegs, &MRI](raw_ostream &OS) {
576 const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo();
577 for (unsigned I = 0, E = MRI.getNumVirtRegs(); I != E; ++I) {
578 Register Reg = Register::index2VirtReg(I);
579 auto It = LiveRegs.find(Reg);
580 if (It != LiveRegs.end() && It->second.any())
581 OS << ' ' << printVRegOrUnit(Reg, TRI) << ':'
582 << PrintLaneMask(It->second);
583 }
584 OS << '\n';
585 });
586 }
587
dump() const588 void GCNRegPressure::dump() const { dbgs() << print(*this); }
589
590 static cl::opt<bool> UseDownwardTracker(
591 "amdgpu-print-rp-downward",
592 cl::desc("Use GCNDownwardRPTracker for GCNRegPressurePrinter pass"),
593 cl::init(false), cl::Hidden);
594
595 char llvm::GCNRegPressurePrinter::ID = 0;
596 char &llvm::GCNRegPressurePrinterID = GCNRegPressurePrinter::ID;
597
598 INITIALIZE_PASS(GCNRegPressurePrinter, "amdgpu-print-rp", "", true, true)
599
600 // Return lanemask of Reg's subregs that are live-through at [Begin, End] and
601 // are fully covered by Mask.
602 static LaneBitmask
getRegLiveThroughMask(const MachineRegisterInfo & MRI,const LiveIntervals & LIS,Register Reg,SlotIndex Begin,SlotIndex End,LaneBitmask Mask=LaneBitmask::getAll ())603 getRegLiveThroughMask(const MachineRegisterInfo &MRI, const LiveIntervals &LIS,
604 Register Reg, SlotIndex Begin, SlotIndex End,
605 LaneBitmask Mask = LaneBitmask::getAll()) {
606
607 auto IsInOneSegment = [Begin, End](const LiveRange &LR) -> bool {
608 auto *Segment = LR.getSegmentContaining(Begin);
609 return Segment && Segment->contains(End);
610 };
611
612 LaneBitmask LiveThroughMask;
613 const LiveInterval &LI = LIS.getInterval(Reg);
614 if (LI.hasSubRanges()) {
615 for (auto &SR : LI.subranges()) {
616 if ((SR.LaneMask & Mask) == SR.LaneMask && IsInOneSegment(SR))
617 LiveThroughMask |= SR.LaneMask;
618 }
619 } else {
620 LaneBitmask RegMask = MRI.getMaxLaneMaskForVReg(Reg);
621 if ((RegMask & Mask) == RegMask && IsInOneSegment(LI))
622 LiveThroughMask = RegMask;
623 }
624
625 return LiveThroughMask;
626 }
627
runOnMachineFunction(MachineFunction & MF)628 bool GCNRegPressurePrinter::runOnMachineFunction(MachineFunction &MF) {
629 const MachineRegisterInfo &MRI = MF.getRegInfo();
630 const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo();
631 const LiveIntervals &LIS = getAnalysis<LiveIntervalsWrapperPass>().getLIS();
632
633 auto &OS = dbgs();
634
635 // Leading spaces are important for YAML syntax.
636 #define PFX " "
637
638 OS << "---\nname: " << MF.getName() << "\nbody: |\n";
639
640 auto printRP = [](const GCNRegPressure &RP) {
641 return Printable([&RP](raw_ostream &OS) {
642 OS << format(PFX " %-5d", RP.getSGPRNum())
643 << format(" %-5d", RP.getVGPRNum(false));
644 });
645 };
646
647 auto ReportLISMismatchIfAny = [&](const GCNRPTracker::LiveRegSet &TrackedLR,
648 const GCNRPTracker::LiveRegSet &LISLR) {
649 if (LISLR != TrackedLR) {
650 OS << PFX " mis LIS: " << llvm::print(LISLR, MRI)
651 << reportMismatch(LISLR, TrackedLR, TRI, PFX " ");
652 }
653 };
654
655 // Register pressure before and at an instruction (in program order).
656 SmallVector<std::pair<GCNRegPressure, GCNRegPressure>, 16> RP;
657
658 for (auto &MBB : MF) {
659 RP.clear();
660 RP.reserve(MBB.size());
661
662 OS << PFX;
663 MBB.printName(OS);
664 OS << ":\n";
665
666 SlotIndex MBBStartSlot = LIS.getSlotIndexes()->getMBBStartIdx(&MBB);
667 SlotIndex MBBEndSlot = LIS.getSlotIndexes()->getMBBEndIdx(&MBB);
668
669 GCNRPTracker::LiveRegSet LiveIn, LiveOut;
670 GCNRegPressure RPAtMBBEnd;
671
672 if (UseDownwardTracker) {
673 if (MBB.empty()) {
674 LiveIn = LiveOut = getLiveRegs(MBBStartSlot, LIS, MRI);
675 RPAtMBBEnd = getRegPressure(MRI, LiveIn);
676 } else {
677 GCNDownwardRPTracker RPT(LIS);
678 RPT.reset(MBB.front());
679
680 LiveIn = RPT.getLiveRegs();
681
682 while (!RPT.advanceBeforeNext()) {
683 GCNRegPressure RPBeforeMI = RPT.getPressure();
684 RPT.advanceToNext();
685 RP.emplace_back(RPBeforeMI, RPT.getPressure());
686 }
687
688 LiveOut = RPT.getLiveRegs();
689 RPAtMBBEnd = RPT.getPressure();
690 }
691 } else {
692 GCNUpwardRPTracker RPT(LIS);
693 RPT.reset(MRI, MBBEndSlot);
694
695 LiveOut = RPT.getLiveRegs();
696 RPAtMBBEnd = RPT.getPressure();
697
698 for (auto &MI : reverse(MBB)) {
699 RPT.resetMaxPressure();
700 RPT.recede(MI);
701 if (!MI.isDebugInstr())
702 RP.emplace_back(RPT.getPressure(), RPT.getMaxPressure());
703 }
704
705 LiveIn = RPT.getLiveRegs();
706 }
707
708 OS << PFX " Live-in: " << llvm::print(LiveIn, MRI);
709 if (!UseDownwardTracker)
710 ReportLISMismatchIfAny(LiveIn, getLiveRegs(MBBStartSlot, LIS, MRI));
711
712 OS << PFX " SGPR VGPR\n";
713 int I = 0;
714 for (auto &MI : MBB) {
715 if (!MI.isDebugInstr()) {
716 auto &[RPBeforeInstr, RPAtInstr] =
717 RP[UseDownwardTracker ? I : (RP.size() - 1 - I)];
718 ++I;
719 OS << printRP(RPBeforeInstr) << '\n' << printRP(RPAtInstr) << " ";
720 } else
721 OS << PFX " ";
722 MI.print(OS);
723 }
724 OS << printRP(RPAtMBBEnd) << '\n';
725
726 OS << PFX " Live-out:" << llvm::print(LiveOut, MRI);
727 if (UseDownwardTracker)
728 ReportLISMismatchIfAny(LiveOut, getLiveRegs(MBBEndSlot, LIS, MRI));
729
730 GCNRPTracker::LiveRegSet LiveThrough;
731 for (auto [Reg, Mask] : LiveIn) {
732 LaneBitmask MaskIntersection = Mask & LiveOut.lookup(Reg);
733 if (MaskIntersection.any()) {
734 LaneBitmask LTMask = getRegLiveThroughMask(
735 MRI, LIS, Reg, MBBStartSlot, MBBEndSlot, MaskIntersection);
736 if (LTMask.any())
737 LiveThrough[Reg] = LTMask;
738 }
739 }
740 OS << PFX " Live-thr:" << llvm::print(LiveThrough, MRI);
741 OS << printRP(getRegPressure(MRI, LiveThrough)) << '\n';
742 }
743 OS << "...\n";
744 return false;
745
746 #undef PFX
747 }