blob: 427ef94ad7dcece8729dcec6b24e064a0f609a40 [file] [log] [blame]
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +00001//===---------- SplitKit.cpp - Toolkit for splitting live ranges ----------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains the SplitAnalysis class as well as mutator functions for
11// live range splitting.
12//
13//===----------------------------------------------------------------------===//
14
Jakob Stoklund Olesen376dcbd2010-11-03 20:39:23 +000015#define DEBUG_TYPE "regalloc"
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +000016#include "SplitKit.h"
Jakob Stoklund Olesena17768f2010-10-14 23:49:52 +000017#include "LiveRangeEdit.h"
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +000018#include "VirtRegMap.h"
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +000019#include "llvm/ADT/Statistic.h"
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +000020#include "llvm/CodeGen/LiveIntervalAnalysis.h"
Jakob Stoklund Olesend68f4582010-10-28 20:34:50 +000021#include "llvm/CodeGen/MachineDominators.h"
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +000022#include "llvm/CodeGen/MachineInstrBuilder.h"
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +000023#include "llvm/CodeGen/MachineRegisterInfo.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/raw_ostream.h"
Jakob Stoklund Olesen6a0dc072010-07-20 21:46:58 +000026#include "llvm/Target/TargetInstrInfo.h"
27#include "llvm/Target/TargetMachine.h"
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +000028
29using namespace llvm;
30
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +000031STATISTIC(NumFinished, "Number of splits finished");
32STATISTIC(NumSimple, "Number of splits that were simple");
33
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +000034//===----------------------------------------------------------------------===//
35// Split Analysis
36//===----------------------------------------------------------------------===//
37
Jakob Stoklund Olesen1b847de2011-02-19 00:53:42 +000038SplitAnalysis::SplitAnalysis(const VirtRegMap &vrm,
Jakob Stoklund Olesenf2c6e362010-07-20 23:50:15 +000039 const LiveIntervals &lis,
40 const MachineLoopInfo &mli)
Jakob Stoklund Olesen1b847de2011-02-19 00:53:42 +000041 : MF(vrm.getMachineFunction()),
42 VRM(vrm),
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +000043 LIS(lis),
44 Loops(mli),
Jakob Stoklund Olesen1b847de2011-02-19 00:53:42 +000045 TII(*MF.getTarget().getInstrInfo()),
Jakob Stoklund Olesen1a774452011-04-05 04:20:27 +000046 CurLI(0),
47 LastSplitPoint(MF.getNumBlockIDs()) {}
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +000048
49void SplitAnalysis::clear() {
Jakob Stoklund Olesenb5fa9332011-01-18 21:13:27 +000050 UseSlots.clear();
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +000051 UseBlocks.clear();
52 ThroughBlocks.clear();
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +000053 CurLI = 0;
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +000054}
55
Jakob Stoklund Olesen1a774452011-04-05 04:20:27 +000056SlotIndex SplitAnalysis::computeLastSplitPoint(unsigned Num) {
57 const MachineBasicBlock *MBB = MF.getBlockNumbered(Num);
58 const MachineBasicBlock *LPad = MBB->getLandingPadSuccessor();
59 std::pair<SlotIndex, SlotIndex> &LSP = LastSplitPoint[Num];
60
61 // Compute split points on the first call. The pair is independent of the
62 // current live interval.
63 if (!LSP.first.isValid()) {
64 MachineBasicBlock::const_iterator FirstTerm = MBB->getFirstTerminator();
65 if (FirstTerm == MBB->end())
66 LSP.first = LIS.getMBBEndIdx(MBB);
67 else
68 LSP.first = LIS.getInstructionIndex(FirstTerm);
69
70 // If there is a landing pad successor, also find the call instruction.
71 if (!LPad)
72 return LSP.first;
73 // There may not be a call instruction (?) in which case we ignore LPad.
74 LSP.second = LSP.first;
75 for (MachineBasicBlock::const_iterator I = FirstTerm, E = MBB->begin();
76 I != E; --I)
77 if (I->getDesc().isCall()) {
78 LSP.second = LIS.getInstructionIndex(I);
79 break;
80 }
81 }
82
83 // If CurLI is live into a landing pad successor, move the last split point
84 // back to the call that may throw.
Jakob Stoklund Olesen71d9e652011-04-05 23:43:16 +000085 if (LPad && LSP.second.isValid() && LIS.isLiveInToMBB(*CurLI, LPad))
Jakob Stoklund Olesen1a774452011-04-05 04:20:27 +000086 return LSP.second;
87 else
88 return LSP.first;
Jakob Stoklund Olesen6a0dc072010-07-20 21:46:58 +000089}
90
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +000091/// analyzeUses - Count instructions, basic blocks, and loops using CurLI.
Jakob Stoklund Olesenabff2802010-07-20 16:12:37 +000092void SplitAnalysis::analyzeUses() {
Jakob Stoklund Olesena2948ef2011-04-05 15:18:18 +000093 assert(UseSlots.empty() && "Call clear first");
94
95 // First get all the defs from the interval values. This provides the correct
96 // slots for early clobbers.
97 for (LiveInterval::const_vni_iterator I = CurLI->vni_begin(),
98 E = CurLI->vni_end(); I != E; ++I)
99 if (!(*I)->isPHIDef() && !(*I)->isUnused())
100 UseSlots.push_back((*I)->def);
101
102 // Get use slots form the use-def chain.
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000103 const MachineRegisterInfo &MRI = MF.getRegInfo();
Jakob Stoklund Olesena2948ef2011-04-05 15:18:18 +0000104 for (MachineRegisterInfo::use_nodbg_iterator
105 I = MRI.use_nodbg_begin(CurLI->reg), E = MRI.use_nodbg_end(); I != E;
106 ++I)
107 if (!I.getOperand().isUndef())
108 UseSlots.push_back(LIS.getInstructionIndex(&*I).getDefIndex());
109
Jakob Stoklund Olesenb5fa9332011-01-18 21:13:27 +0000110 array_pod_sort(UseSlots.begin(), UseSlots.end());
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000111
Jakob Stoklund Olesena2948ef2011-04-05 15:18:18 +0000112 // Remove duplicates, keeping the smaller slot for each instruction.
113 // That is what we want for early clobbers.
114 UseSlots.erase(std::unique(UseSlots.begin(), UseSlots.end(),
115 SlotIndex::isSameInstr),
116 UseSlots.end());
117
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000118 // Compute per-live block info.
119 if (!calcLiveBlockInfo()) {
120 // FIXME: calcLiveBlockInfo found inconsistencies in the live range.
121 // I am looking at you, SimpleRegisterCoalescing!
122 DEBUG(dbgs() << "*** Fixing inconsistent live interval! ***\n");
123 const_cast<LiveIntervals&>(LIS)
124 .shrinkToUses(const_cast<LiveInterval*>(CurLI));
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +0000125 UseBlocks.clear();
126 ThroughBlocks.clear();
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000127 bool fixed = calcLiveBlockInfo();
128 (void)fixed;
129 assert(fixed && "Couldn't fix broken live interval");
130 }
131
Jakob Stoklund Olesenef1f5cc2011-03-27 22:49:23 +0000132 DEBUG(dbgs() << "Analyze counted "
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +0000133 << UseSlots.size() << " instrs in "
134 << UseBlocks.size() << " blocks, through "
Jakob Stoklund Olesenf4afdfc2011-04-09 02:59:09 +0000135 << NumThroughBlocks << " blocks.\n");
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +0000136}
137
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000138/// calcLiveBlockInfo - Fill the LiveBlocks array with information about blocks
139/// where CurLI is live.
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000140bool SplitAnalysis::calcLiveBlockInfo() {
Jakob Stoklund Olesenf4afdfc2011-04-09 02:59:09 +0000141 ThroughBlocks.resize(MF.getNumBlockIDs());
142 NumThroughBlocks = 0;
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000143 if (CurLI->empty())
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000144 return true;
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000145
146 LiveInterval::const_iterator LVI = CurLI->begin();
147 LiveInterval::const_iterator LVE = CurLI->end();
148
149 SmallVectorImpl<SlotIndex>::const_iterator UseI, UseE;
150 UseI = UseSlots.begin();
151 UseE = UseSlots.end();
152
153 // Loop over basic blocks where CurLI is live.
154 MachineFunction::iterator MFI = LIS.getMBBFromIndex(LVI->start);
155 for (;;) {
156 BlockInfo BI;
157 BI.MBB = MFI;
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000158 SlotIndex Start, Stop;
159 tie(Start, Stop) = LIS.getSlotIndexes()->getMBBRange(BI.MBB);
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000160
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000161 // LVI is the first live segment overlapping MBB.
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000162 BI.LiveIn = LVI->start <= Start;
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000163 if (!BI.LiveIn)
164 BI.Def = LVI->start;
165
166 // Find the first and last uses in the block.
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +0000167 bool Uses = UseI != UseE && *UseI < Stop;
168 if (Uses) {
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000169 BI.FirstUse = *UseI;
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000170 assert(BI.FirstUse >= Start);
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000171 do ++UseI;
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000172 while (UseI != UseE && *UseI < Stop);
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000173 BI.LastUse = UseI[-1];
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000174 assert(BI.LastUse < Stop);
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000175 }
176
177 // Look for gaps in the live range.
178 bool hasGap = false;
179 BI.LiveOut = true;
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000180 while (LVI->end < Stop) {
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000181 SlotIndex LastStop = LVI->end;
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000182 if (++LVI == LVE || LVI->start >= Stop) {
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000183 BI.Kill = LastStop;
184 BI.LiveOut = false;
185 break;
186 }
187 if (LastStop < LVI->start) {
188 hasGap = true;
189 BI.Kill = LastStop;
190 BI.Def = LVI->start;
191 }
192 }
193
194 // Don't set LiveThrough when the block has a gap.
195 BI.LiveThrough = !hasGap && BI.LiveIn && BI.LiveOut;
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +0000196 if (Uses)
197 UseBlocks.push_back(BI);
Jakob Stoklund Olesenf4afdfc2011-04-09 02:59:09 +0000198 else {
199 ++NumThroughBlocks;
200 ThroughBlocks.set(BI.MBB->getNumber());
201 }
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000202 // FIXME: This should never happen. The live range stops or starts without a
203 // corresponding use. An earlier pass did something wrong.
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +0000204 if (!BI.LiveThrough && !Uses)
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000205 return false;
206
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000207 // LVI is now at LVE or LVI->end >= Stop.
208 if (LVI == LVE)
209 break;
210
211 // Live segment ends exactly at Stop. Move to the next segment.
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000212 if (LVI->end == Stop && ++LVI == LVE)
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000213 break;
214
215 // Pick the next basic block.
Jakob Stoklund Olesen6c8afd72011-04-04 15:32:15 +0000216 if (LVI->start < Stop)
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000217 ++MFI;
218 else
219 MFI = LIS.getMBBFromIndex(LVI->start);
220 }
Jakob Stoklund Olesen2b0f9e72011-03-05 18:33:49 +0000221 return true;
Jakob Stoklund Olesenf0ac26c2011-02-09 22:50:26 +0000222}
223
Jakob Stoklund Olesen9f4b8932011-04-26 22:33:12 +0000224unsigned SplitAnalysis::countLiveBlocks(const LiveInterval *cli) const {
225 if (cli->empty())
226 return 0;
227 LiveInterval *li = const_cast<LiveInterval*>(cli);
228 LiveInterval::iterator LVI = li->begin();
229 LiveInterval::iterator LVE = li->end();
230 unsigned Count = 0;
231
232 // Loop over basic blocks where li is live.
233 MachineFunction::const_iterator MFI = LIS.getMBBFromIndex(LVI->start);
234 SlotIndex Stop = LIS.getMBBEndIdx(MFI);
235 for (;;) {
236 ++Count;
237 LVI = li->advanceTo(LVI, Stop);
238 if (LVI == LVE)
239 return Count;
240 do {
241 ++MFI;
242 Stop = LIS.getMBBEndIdx(MFI);
243 } while (Stop <= LVI->start);
244 }
245}
246
Jakob Stoklund Olesen06c0f252011-02-21 23:09:46 +0000247bool SplitAnalysis::isOriginalEndpoint(SlotIndex Idx) const {
248 unsigned OrigReg = VRM.getOriginal(CurLI->reg);
249 const LiveInterval &Orig = LIS.getInterval(OrigReg);
250 assert(!Orig.empty() && "Splitting empty interval?");
251 LiveInterval::const_iterator I = Orig.find(Idx);
252
253 // Range containing Idx should begin at Idx.
254 if (I != Orig.end() && I->start <= Idx)
255 return I->start == Idx;
256
257 // Range does not contain Idx, previous must end at Idx.
258 return I != Orig.begin() && (--I)->end == Idx;
259}
260
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +0000261void SplitAnalysis::analyze(const LiveInterval *li) {
262 clear();
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000263 CurLI = li;
Jakob Stoklund Olesenabff2802010-07-20 16:12:37 +0000264 analyzeUses();
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +0000265}
266
Jakob Stoklund Olesen697483a2010-12-15 17:49:52 +0000267
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +0000268//===----------------------------------------------------------------------===//
269// Split Editor
270//===----------------------------------------------------------------------===//
271
272/// Create a new SplitEditor for editing the LiveInterval analyzed by SA.
Jakob Stoklund Olesend68f4582010-10-28 20:34:50 +0000273SplitEditor::SplitEditor(SplitAnalysis &sa,
274 LiveIntervals &lis,
275 VirtRegMap &vrm,
Jakob Stoklund Olesenbece06f2011-03-03 01:29:13 +0000276 MachineDominatorTree &mdt)
Jakob Stoklund Olesen0eeca442011-02-19 00:42:33 +0000277 : SA(sa), LIS(lis), VRM(vrm),
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000278 MRI(vrm.getMachineFunction().getRegInfo()),
Eric Christopher0f438112011-02-03 06:18:29 +0000279 MDT(mdt),
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000280 TII(*vrm.getMachineFunction().getTarget().getInstrInfo()),
281 TRI(*vrm.getMachineFunction().getTarget().getRegisterInfo()),
Jakob Stoklund Olesenbece06f2011-03-03 01:29:13 +0000282 Edit(0),
Eric Christopher0f438112011-02-03 06:18:29 +0000283 OpenIdx(0),
284 RegAssign(Allocator)
Jakob Stoklund Olesenbece06f2011-03-03 01:29:13 +0000285{}
286
287void SplitEditor::reset(LiveRangeEdit &lre) {
288 Edit = &lre;
289 OpenIdx = 0;
290 RegAssign.clear();
291 Values.clear();
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000292
293 // We don't need to clear LiveOutCache, only LiveOutSeen entries are read.
294 LiveOutSeen.clear();
Jakob Stoklund Olesenbece06f2011-03-03 01:29:13 +0000295
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000296 // We don't need an AliasAnalysis since we will only be performing
297 // cheap-as-a-copy remats anyway.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000298 Edit->anyRematerializable(LIS, TII, 0);
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +0000299}
300
Eric Christopher0f438112011-02-03 06:18:29 +0000301void SplitEditor::dump() const {
302 if (RegAssign.empty()) {
303 dbgs() << " empty\n";
304 return;
305 }
306
307 for (RegAssignMap::const_iterator I = RegAssign.begin(); I.valid(); ++I)
308 dbgs() << " [" << I.start() << ';' << I.stop() << "):" << I.value();
309 dbgs() << '\n';
Jakob Stoklund Olesen5fa42a42010-09-21 22:32:21 +0000310}
311
Jakob Stoklund Olesen670ccd12011-03-01 23:14:53 +0000312VNInfo *SplitEditor::defValue(unsigned RegIdx,
313 const VNInfo *ParentVNI,
314 SlotIndex Idx) {
315 assert(ParentVNI && "Mapping NULL value");
316 assert(Idx.isValid() && "Invalid SlotIndex");
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000317 assert(Edit->getParent().getVNInfoAt(Idx) == ParentVNI && "Bad Parent VNI");
318 LiveInterval *LI = Edit->get(RegIdx);
Jakob Stoklund Olesen670ccd12011-03-01 23:14:53 +0000319
320 // Create a new value.
321 VNInfo *VNI = LI->getNextValue(Idx, 0, LIS.getVNInfoAllocator());
322
Jakob Stoklund Olesen670ccd12011-03-01 23:14:53 +0000323 // Use insert for lookup, so we can add missing values with a second lookup.
324 std::pair<ValueMap::iterator, bool> InsP =
325 Values.insert(std::make_pair(std::make_pair(RegIdx, ParentVNI->id), VNI));
326
327 // This was the first time (RegIdx, ParentVNI) was mapped.
328 // Keep it as a simple def without any liveness.
329 if (InsP.second)
330 return VNI;
331
332 // If the previous value was a simple mapping, add liveness for it now.
333 if (VNInfo *OldVNI = InsP.first->second) {
334 SlotIndex Def = OldVNI->def;
335 LI->addRange(LiveRange(Def, Def.getNextSlot(), OldVNI));
336 // No longer a simple mapping.
337 InsP.first->second = 0;
338 }
339
340 // This is a complex mapping, add liveness for VNI
341 SlotIndex Def = VNI->def;
342 LI->addRange(LiveRange(Def, Def.getNextSlot(), VNI));
343
344 return VNI;
345}
346
347void SplitEditor::markComplexMapped(unsigned RegIdx, const VNInfo *ParentVNI) {
348 assert(ParentVNI && "Mapping NULL value");
349 VNInfo *&VNI = Values[std::make_pair(RegIdx, ParentVNI->id)];
350
351 // ParentVNI was either unmapped or already complex mapped. Either way.
352 if (!VNI)
353 return;
354
355 // This was previously a single mapping. Make sure the old def is represented
356 // by a trivial live range.
357 SlotIndex Def = VNI->def;
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000358 Edit->get(RegIdx)->addRange(LiveRange(Def, Def.getNextSlot(), VNI));
Jakob Stoklund Olesen670ccd12011-03-01 23:14:53 +0000359 VNI = 0;
360}
361
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000362// extendRange - Extend the live range to reach Idx.
363// Potentially create phi-def values.
364void SplitEditor::extendRange(unsigned RegIdx, SlotIndex Idx) {
365 assert(Idx.isValid() && "Invalid SlotIndex");
366 MachineBasicBlock *IdxMBB = LIS.getMBBFromIndex(Idx);
367 assert(IdxMBB && "No MBB at Idx");
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000368 LiveInterval *LI = Edit->get(RegIdx);
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000369
370 // Is there a def in the same MBB we can extend?
371 if (LI->extendInBlock(LIS.getMBBStartIdx(IdxMBB), Idx))
372 return;
373
374 // Now for the fun part. We know that ParentVNI potentially has multiple defs,
375 // and we may need to create even more phi-defs to preserve VNInfo SSA form.
376 // Perform a search for all predecessor blocks where we know the dominating
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000377 // VNInfo.
378 VNInfo *VNI = findReachingDefs(LI, IdxMBB, Idx.getNextSlot());
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000379
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000380 // When there were multiple different values, we may need new PHIs.
381 if (!VNI)
382 return updateSSA();
383
384 // Poor man's SSA update for the single-value case.
385 LiveOutPair LOP(VNI, MDT[LIS.getMBBFromIndex(VNI->def)]);
386 for (SmallVectorImpl<LiveInBlock>::iterator I = LiveInBlocks.begin(),
387 E = LiveInBlocks.end(); I != E; ++I) {
388 MachineBasicBlock *MBB = I->DomNode->getBlock();
389 SlotIndex Start = LIS.getMBBStartIdx(MBB);
390 if (I->Kill.isValid())
391 LI->addRange(LiveRange(Start, I->Kill, VNI));
392 else {
393 LiveOutCache[MBB] = LOP;
394 LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
395 }
396 }
397}
398
399/// findReachingDefs - Search the CFG for known live-out values.
400/// Add required live-in blocks to LiveInBlocks.
401VNInfo *SplitEditor::findReachingDefs(LiveInterval *LI,
402 MachineBasicBlock *KillMBB,
403 SlotIndex Kill) {
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000404 // Initialize the live-out cache the first time it is needed.
405 if (LiveOutSeen.empty()) {
406 unsigned N = VRM.getMachineFunction().getNumBlockIDs();
407 LiveOutSeen.resize(N);
408 LiveOutCache.resize(N);
409 }
410
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000411 // Blocks where LI should be live-in.
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000412 SmallVector<MachineBasicBlock*, 16> WorkList(1, KillMBB);
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000413
Jakob Stoklund Olesen87017682011-03-03 01:29:10 +0000414 // Remember if we have seen more than one value.
415 bool UniqueVNI = true;
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000416 VNInfo *TheVNI = 0;
Jakob Stoklund Olesen87017682011-03-03 01:29:10 +0000417
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000418 // Using LiveOutCache as a visited set, perform a BFS for all reaching defs.
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000419 for (unsigned i = 0; i != WorkList.size(); ++i) {
420 MachineBasicBlock *MBB = WorkList[i];
Jakob Stoklund Olesen7cec1792011-03-18 03:06:02 +0000421 assert(!MBB->pred_empty() && "Value live-in to entry block?");
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000422 for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
423 PE = MBB->pred_end(); PI != PE; ++PI) {
424 MachineBasicBlock *Pred = *PI;
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000425 LiveOutPair &LOP = LiveOutCache[Pred];
426
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000427 // Is this a known live-out block?
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000428 if (LiveOutSeen.test(Pred->getNumber())) {
429 if (VNInfo *VNI = LOP.first) {
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000430 if (TheVNI && TheVNI != VNI)
Jakob Stoklund Olesen87017682011-03-03 01:29:10 +0000431 UniqueVNI = false;
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000432 TheVNI = VNI;
Jakob Stoklund Olesen87017682011-03-03 01:29:10 +0000433 }
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000434 continue;
Jakob Stoklund Olesen87017682011-03-03 01:29:10 +0000435 }
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000436
437 // First time. LOP is garbage and must be cleared below.
438 LiveOutSeen.set(Pred->getNumber());
439
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000440 // Does Pred provide a live-out value?
441 SlotIndex Start, Last;
442 tie(Start, Last) = LIS.getSlotIndexes()->getMBBRange(Pred);
443 Last = Last.getPrevSlot();
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000444 VNInfo *VNI = LI->extendInBlock(Start, Last);
445 LOP.first = VNI;
446 if (VNI) {
447 LOP.second = MDT[LIS.getMBBFromIndex(VNI->def)];
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000448 if (TheVNI && TheVNI != VNI)
Jakob Stoklund Olesen87017682011-03-03 01:29:10 +0000449 UniqueVNI = false;
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000450 TheVNI = VNI;
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000451 continue;
452 }
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000453 LOP.second = 0;
454
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000455 // No, we need a live-in value for Pred as well
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000456 if (Pred != KillMBB)
457 WorkList.push_back(Pred);
Jakob Stoklund Olesen87017682011-03-03 01:29:10 +0000458 else
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000459 // Loopback to KillMBB, so value is really live through.
460 Kill = SlotIndex();
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000461 }
462 }
463
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000464 // Transfer WorkList to LiveInBlocks in reverse order.
465 // This ordering works best with updateSSA().
466 LiveInBlocks.clear();
467 LiveInBlocks.reserve(WorkList.size());
468 while(!WorkList.empty())
469 LiveInBlocks.push_back(MDT[WorkList.pop_back_val()]);
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000470
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000471 // The kill block may not be live-through.
472 assert(LiveInBlocks.back().DomNode->getBlock() == KillMBB);
473 LiveInBlocks.back().Kill = Kill;
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000474
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000475 return UniqueVNI ? TheVNI : 0;
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000476}
477
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000478void SplitEditor::updateSSA() {
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000479 // This is essentially the same iterative algorithm that SSAUpdater uses,
480 // except we already have a dominator tree, so we don't have to recompute it.
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000481 unsigned Changes;
482 do {
483 Changes = 0;
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000484 // Propagate live-out values down the dominator tree, inserting phi-defs
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000485 // when necessary.
486 for (SmallVectorImpl<LiveInBlock>::iterator I = LiveInBlocks.begin(),
487 E = LiveInBlocks.end(); I != E; ++I) {
488 MachineDomTreeNode *Node = I->DomNode;
489 // Skip block if the live-in value has already been determined.
490 if (!Node)
491 continue;
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000492 MachineBasicBlock *MBB = Node->getBlock();
493 MachineDomTreeNode *IDom = Node->getIDom();
494 LiveOutPair IDomValue;
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000495
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000496 // We need a live-in value to a block with no immediate dominator?
497 // This is probably an unreachable block that has survived somehow.
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000498 bool needPHI = !IDom || !LiveOutSeen.test(IDom->getBlock()->getNumber());
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000499
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000500 // IDom dominates all of our predecessors, but it may not be their
501 // immediate dominator. Check if any of them have live-out values that are
502 // properly dominated by IDom. If so, we need a phi-def here.
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000503 if (!needPHI) {
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000504 IDomValue = LiveOutCache[IDom->getBlock()];
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000505 for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
506 PE = MBB->pred_end(); PI != PE; ++PI) {
507 LiveOutPair Value = LiveOutCache[*PI];
508 if (!Value.first || Value.first == IDomValue.first)
509 continue;
510 // This predecessor is carrying something other than IDomValue.
511 // It could be because IDomValue hasn't propagated yet, or it could be
512 // because MBB is in the dominance frontier of that value.
513 if (MDT.dominates(IDom, Value.second)) {
514 needPHI = true;
515 break;
516 }
517 }
518 }
519
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000520 // The value may be live-through even if Kill is set, as can happen when
521 // we are called from extendRange. In that case LiveOutSeen is true, and
522 // LiveOutCache indicates a foreign or missing value.
523 LiveOutPair &LOP = LiveOutCache[MBB];
524
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000525 // Create a phi-def if required.
526 if (needPHI) {
527 ++Changes;
528 SlotIndex Start = LIS.getMBBStartIdx(MBB);
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000529 unsigned RegIdx = RegAssign.lookup(Start);
530 LiveInterval *LI = Edit->get(RegIdx);
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000531 VNInfo *VNI = LI->getNextValue(Start, 0, LIS.getVNInfoAllocator());
532 VNI->setIsPHIDef(true);
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000533 I->Value = VNI;
534 // This block is done, we know the final value.
535 I->DomNode = 0;
536 if (I->Kill.isValid())
537 LI->addRange(LiveRange(Start, I->Kill, VNI));
538 else {
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000539 LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000540 LOP = LiveOutPair(VNI, Node);
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000541 }
542 } else if (IDomValue.first) {
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000543 // No phi-def here. Remember incoming value.
544 I->Value = IDomValue.first;
545 if (I->Kill.isValid())
546 continue;
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000547 // Propagate IDomValue if needed:
548 // MBB is live-out and doesn't define its own value.
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000549 if (LOP.second != Node && LOP.first != IDomValue.first) {
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000550 ++Changes;
Jakob Stoklund Olesen13ba2da2011-03-04 00:15:36 +0000551 LOP = IDomValue;
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000552 }
553 }
554 }
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000555 } while (Changes);
556
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000557 // The values in LiveInBlocks are now accurate. No more phi-defs are needed
558 // for these blocks, so we can color the live ranges.
559 for (SmallVectorImpl<LiveInBlock>::iterator I = LiveInBlocks.begin(),
560 E = LiveInBlocks.end(); I != E; ++I) {
561 if (!I->DomNode)
562 continue;
563 assert(I->Value && "No live-in value found");
564 MachineBasicBlock *MBB = I->DomNode->getBlock();
565 SlotIndex Start = LIS.getMBBStartIdx(MBB);
566 unsigned RegIdx = RegAssign.lookup(Start);
567 LiveInterval *LI = Edit->get(RegIdx);
568 LI->addRange(LiveRange(Start, I->Kill.isValid() ?
569 I->Kill : LIS.getMBBEndIdx(MBB), I->Value));
570 }
Jakob Stoklund Olesen1c38ba62011-03-02 01:59:34 +0000571}
572
Eric Christopher0f438112011-02-03 06:18:29 +0000573VNInfo *SplitEditor::defFromParent(unsigned RegIdx,
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000574 VNInfo *ParentVNI,
575 SlotIndex UseIdx,
576 MachineBasicBlock &MBB,
577 MachineBasicBlock::iterator I) {
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000578 MachineInstr *CopyMI = 0;
579 SlotIndex Def;
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000580 LiveInterval *LI = Edit->get(RegIdx);
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000581
582 // Attempt cheap-as-a-copy rematerialization.
583 LiveRangeEdit::Remat RM(ParentVNI);
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000584 if (Edit->canRematerializeAt(RM, UseIdx, true, LIS)) {
585 Def = Edit->rematerializeAt(MBB, I, LI->reg, RM, LIS, TII, TRI);
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000586 } else {
587 // Can't remat, just insert a copy from parent.
Eric Christopher0f438112011-02-03 06:18:29 +0000588 CopyMI = BuildMI(MBB, I, DebugLoc(), TII.get(TargetOpcode::COPY), LI->reg)
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000589 .addReg(Edit->getReg());
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000590 Def = LIS.InsertMachineInstrInMaps(CopyMI).getDefIndex();
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000591 }
592
Jakob Stoklund Olesen670ccd12011-03-01 23:14:53 +0000593 // Define the value in Reg.
594 VNInfo *VNI = defValue(RegIdx, ParentVNI, Def);
595 VNI->setCopy(CopyMI);
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000596 return VNI;
597}
598
Jakob Stoklund Olesen7536f722010-08-04 22:08:39 +0000599/// Create a new virtual register and live interval.
Jakob Stoklund Olesene1b43c32011-04-12 18:11:31 +0000600unsigned SplitEditor::openIntv() {
Eric Christopher0f438112011-02-03 06:18:29 +0000601 // Create the complement as index 0.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000602 if (Edit->empty())
Jakob Stoklund Olesen6a3dbd32011-03-17 20:37:07 +0000603 Edit->create(LIS, VRM);
Eric Christopher0f438112011-02-03 06:18:29 +0000604
605 // Create the open interval.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000606 OpenIdx = Edit->size();
Jakob Stoklund Olesen6a3dbd32011-03-17 20:37:07 +0000607 Edit->create(LIS, VRM);
Jakob Stoklund Olesene1b43c32011-04-12 18:11:31 +0000608 return OpenIdx;
609}
610
611void SplitEditor::selectIntv(unsigned Idx) {
612 assert(Idx != 0 && "Cannot select the complement interval");
613 assert(Idx < Edit->size() && "Can only select previously opened interval");
614 OpenIdx = Idx;
Jakob Stoklund Olesen7536f722010-08-04 22:08:39 +0000615}
616
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000617SlotIndex SplitEditor::enterIntvBefore(SlotIndex Idx) {
Eric Christopher0f438112011-02-03 06:18:29 +0000618 assert(OpenIdx && "openIntv not called before enterIntvBefore");
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000619 DEBUG(dbgs() << " enterIntvBefore " << Idx);
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000620 Idx = Idx.getBaseIndex();
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000621 VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx);
Jakob Stoklund Olesenf6a129a2010-09-16 00:01:36 +0000622 if (!ParentVNI) {
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000623 DEBUG(dbgs() << ": not live\n");
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000624 return Idx;
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +0000625 }
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000626 DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000627 MachineInstr *MI = LIS.getInstructionFromIndex(Idx);
Jakob Stoklund Olesenf6a129a2010-09-16 00:01:36 +0000628 assert(MI && "enterIntvBefore called with invalid index");
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000629
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000630 VNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Idx, *MI->getParent(), MI);
631 return VNI->def;
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +0000632}
633
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000634SlotIndex SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) {
Eric Christopher0f438112011-02-03 06:18:29 +0000635 assert(OpenIdx && "openIntv not called before enterIntvAtEnd");
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000636 SlotIndex End = LIS.getMBBEndIdx(&MBB);
637 SlotIndex Last = End.getPrevSlot();
638 DEBUG(dbgs() << " enterIntvAtEnd BB#" << MBB.getNumber() << ", " << Last);
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000639 VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Last);
Jakob Stoklund Olesenf6a129a2010-09-16 00:01:36 +0000640 if (!ParentVNI) {
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000641 DEBUG(dbgs() << ": not live\n");
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000642 return End;
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +0000643 }
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000644 DEBUG(dbgs() << ": valno " << ParentVNI->id);
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000645 VNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Last, MBB,
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000646 LIS.getLastSplitPoint(Edit->getParent(), &MBB));
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000647 RegAssign.insert(VNI->def, End, OpenIdx);
Eric Christopher0f438112011-02-03 06:18:29 +0000648 DEBUG(dump());
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000649 return VNI->def;
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +0000650}
651
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000652/// useIntv - indicate that all instructions in MBB should use OpenLI.
Jakob Stoklund Olesen7536f722010-08-04 22:08:39 +0000653void SplitEditor::useIntv(const MachineBasicBlock &MBB) {
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000654 useIntv(LIS.getMBBStartIdx(&MBB), LIS.getMBBEndIdx(&MBB));
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +0000655}
656
Jakob Stoklund Olesen7536f722010-08-04 22:08:39 +0000657void SplitEditor::useIntv(SlotIndex Start, SlotIndex End) {
Eric Christopher0f438112011-02-03 06:18:29 +0000658 assert(OpenIdx && "openIntv not called before useIntv");
659 DEBUG(dbgs() << " useIntv [" << Start << ';' << End << "):");
660 RegAssign.insert(Start, End, OpenIdx);
661 DEBUG(dump());
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +0000662}
663
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000664SlotIndex SplitEditor::leaveIntvAfter(SlotIndex Idx) {
Eric Christopher0f438112011-02-03 06:18:29 +0000665 assert(OpenIdx && "openIntv not called before leaveIntvAfter");
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000666 DEBUG(dbgs() << " leaveIntvAfter " << Idx);
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +0000667
Jakob Stoklund Olesenf6a129a2010-09-16 00:01:36 +0000668 // The interval must be live beyond the instruction at Idx.
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000669 Idx = Idx.getBoundaryIndex();
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000670 VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx);
Jakob Stoklund Olesenf6a129a2010-09-16 00:01:36 +0000671 if (!ParentVNI) {
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000672 DEBUG(dbgs() << ": not live\n");
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000673 return Idx.getNextSlot();
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +0000674 }
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000675 DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +0000676
Jakob Stoklund Olesen01cb34b2011-02-08 18:50:18 +0000677 MachineInstr *MI = LIS.getInstructionFromIndex(Idx);
678 assert(MI && "No instruction at index");
679 VNInfo *VNI = defFromParent(0, ParentVNI, Idx, *MI->getParent(),
680 llvm::next(MachineBasicBlock::iterator(MI)));
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000681 return VNI->def;
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +0000682}
683
Jakob Stoklund Olesen9b057772011-02-09 23:30:25 +0000684SlotIndex SplitEditor::leaveIntvBefore(SlotIndex Idx) {
685 assert(OpenIdx && "openIntv not called before leaveIntvBefore");
686 DEBUG(dbgs() << " leaveIntvBefore " << Idx);
687
688 // The interval must be live into the instruction at Idx.
689 Idx = Idx.getBoundaryIndex();
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000690 VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx);
Jakob Stoklund Olesen9b057772011-02-09 23:30:25 +0000691 if (!ParentVNI) {
692 DEBUG(dbgs() << ": not live\n");
693 return Idx.getNextSlot();
694 }
695 DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
696
697 MachineInstr *MI = LIS.getInstructionFromIndex(Idx);
698 assert(MI && "No instruction at index");
699 VNInfo *VNI = defFromParent(0, ParentVNI, Idx, *MI->getParent(), MI);
700 return VNI->def;
701}
702
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000703SlotIndex SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) {
Eric Christopher0f438112011-02-03 06:18:29 +0000704 assert(OpenIdx && "openIntv not called before leaveIntvAtTop");
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000705 SlotIndex Start = LIS.getMBBStartIdx(&MBB);
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000706 DEBUG(dbgs() << " leaveIntvAtTop BB#" << MBB.getNumber() << ", " << Start);
Jakob Stoklund Olesen7536f722010-08-04 22:08:39 +0000707
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000708 VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Start);
Jakob Stoklund Olesenf6a129a2010-09-16 00:01:36 +0000709 if (!ParentVNI) {
Jakob Stoklund Olesen9b24afe2010-10-07 17:56:35 +0000710 DEBUG(dbgs() << ": not live\n");
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000711 return Start;
Jakob Stoklund Olesen7536f722010-08-04 22:08:39 +0000712 }
713
Eric Christopher0f438112011-02-03 06:18:29 +0000714 VNInfo *VNI = defFromParent(0, ParentVNI, Start, MBB,
Jakob Stoklund Olesencfa71342010-11-10 19:31:50 +0000715 MBB.SkipPHIsAndLabels(MBB.begin()));
Eric Christopher0f438112011-02-03 06:18:29 +0000716 RegAssign.insert(Start, VNI->def, OpenIdx);
717 DEBUG(dump());
Jakob Stoklund Olesen207c8682011-02-03 17:04:16 +0000718 return VNI->def;
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +0000719}
720
Jakob Stoklund Olesen5c716bd2011-02-08 18:50:21 +0000721void SplitEditor::overlapIntv(SlotIndex Start, SlotIndex End) {
722 assert(OpenIdx && "openIntv not called before overlapIntv");
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000723 const VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Start);
724 assert(ParentVNI == Edit->getParent().getVNInfoAt(End.getPrevSlot()) &&
Jakob Stoklund Olesen5c716bd2011-02-08 18:50:21 +0000725 "Parent changes value in extended range");
Jakob Stoklund Olesen5c716bd2011-02-08 18:50:21 +0000726 assert(LIS.getMBBFromIndex(Start) == LIS.getMBBFromIndex(End) &&
727 "Range cannot span basic blocks");
728
Jakob Stoklund Olesend3fdaeb2011-03-02 00:49:28 +0000729 // The complement interval will be extended as needed by extendRange().
Jakob Stoklund Olesenb3dd8262011-04-05 23:43:14 +0000730 if (ParentVNI)
731 markComplexMapped(0, ParentVNI);
Jakob Stoklund Olesen5c716bd2011-02-08 18:50:21 +0000732 DEBUG(dbgs() << " overlapIntv [" << Start << ';' << End << "):");
733 RegAssign.insert(Start, End, OpenIdx);
734 DEBUG(dump());
735}
736
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000737/// transferValues - Transfer all possible values to the new live ranges.
738/// Values that were rematerialized are left alone, they need extendRange().
739bool SplitEditor::transferValues() {
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000740 bool Skipped = false;
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000741 LiveInBlocks.clear();
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000742 RegAssignMap::const_iterator AssignI = RegAssign.begin();
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000743 for (LiveInterval::const_iterator ParentI = Edit->getParent().begin(),
744 ParentE = Edit->getParent().end(); ParentI != ParentE; ++ParentI) {
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000745 DEBUG(dbgs() << " blit " << *ParentI << ':');
746 VNInfo *ParentVNI = ParentI->valno;
747 // RegAssign has holes where RegIdx 0 should be used.
748 SlotIndex Start = ParentI->start;
749 AssignI.advanceTo(Start);
750 do {
751 unsigned RegIdx;
752 SlotIndex End = ParentI->end;
753 if (!AssignI.valid()) {
754 RegIdx = 0;
755 } else if (AssignI.start() <= Start) {
756 RegIdx = AssignI.value();
757 if (AssignI.stop() < End) {
758 End = AssignI.stop();
759 ++AssignI;
760 }
761 } else {
762 RegIdx = 0;
763 End = std::min(End, AssignI.start());
764 }
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000765
766 // The interval [Start;End) is continuously mapped to RegIdx, ParentVNI.
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000767 DEBUG(dbgs() << " [" << Start << ';' << End << ")=" << RegIdx);
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000768 LiveInterval *LI = Edit->get(RegIdx);
769
770 // Check for a simply defined value that can be blitted directly.
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000771 if (VNInfo *VNI = Values.lookup(std::make_pair(RegIdx, ParentVNI->id))) {
772 DEBUG(dbgs() << ':' << VNI->id);
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000773 LI->addRange(LiveRange(Start, End, VNI));
774 Start = End;
775 continue;
776 }
777
778 // Skip rematerialized values, we need to use extendRange() and
779 // extendPHIKillRanges() to completely recompute the live ranges.
780 if (Edit->didRematerialize(ParentVNI)) {
781 DEBUG(dbgs() << "(remat)");
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000782 Skipped = true;
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000783 Start = End;
784 continue;
785 }
786
787 // Initialize the live-out cache the first time it is needed.
788 if (LiveOutSeen.empty()) {
789 unsigned N = VRM.getMachineFunction().getNumBlockIDs();
790 LiveOutSeen.resize(N);
791 LiveOutCache.resize(N);
792 }
793
794 // This value has multiple defs in RegIdx, but it wasn't rematerialized,
795 // so the live range is accurate. Add live-in blocks in [Start;End) to the
796 // LiveInBlocks.
797 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
798 SlotIndex BlockStart, BlockEnd;
799 tie(BlockStart, BlockEnd) = LIS.getSlotIndexes()->getMBBRange(MBB);
800
801 // The first block may be live-in, or it may have its own def.
802 if (Start != BlockStart) {
803 VNInfo *VNI = LI->extendInBlock(BlockStart,
804 std::min(BlockEnd, End).getPrevSlot());
805 assert(VNI && "Missing def for complex mapped value");
806 DEBUG(dbgs() << ':' << VNI->id << "*BB#" << MBB->getNumber());
807 // MBB has its own def. Is it also live-out?
808 if (BlockEnd <= End) {
809 LiveOutSeen.set(MBB->getNumber());
810 LiveOutCache[MBB] = LiveOutPair(VNI, MDT[MBB]);
811 }
812 // Skip to the next block for live-in.
813 ++MBB;
814 BlockStart = BlockEnd;
815 }
816
817 // Handle the live-in blocks covered by [Start;End).
818 assert(Start <= BlockStart && "Expected live-in block");
819 while (BlockStart < End) {
820 DEBUG(dbgs() << ">BB#" << MBB->getNumber());
821 BlockEnd = LIS.getMBBEndIdx(MBB);
822 if (BlockStart == ParentVNI->def) {
823 // This block has the def of a parent PHI, so it isn't live-in.
824 assert(ParentVNI->isPHIDef() && "Non-phi defined at block start?");
825 VNInfo *VNI = LI->extendInBlock(BlockStart,
826 std::min(BlockEnd, End).getPrevSlot());
827 assert(VNI && "Missing def for complex mapped parent PHI");
828 if (End >= BlockEnd) {
829 // Live-out as well.
830 LiveOutSeen.set(MBB->getNumber());
831 LiveOutCache[MBB] = LiveOutPair(VNI, MDT[MBB]);
832 }
833 } else {
834 // This block needs a live-in value.
835 LiveInBlocks.push_back(MDT[MBB]);
836 // The last block covered may not be live-out.
837 if (End < BlockEnd)
838 LiveInBlocks.back().Kill = End;
839 else {
840 // Live-out, but we need updateSSA to tell us the value.
841 LiveOutSeen.set(MBB->getNumber());
Francois Pichetcbc5f402011-04-16 14:20:39 +0000842 LiveOutCache[MBB] = LiveOutPair((VNInfo*)0,
843 (MachineDomTreeNode*)0);
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000844 }
845 }
846 BlockStart = BlockEnd;
847 ++MBB;
848 }
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000849 Start = End;
850 } while (Start != ParentI->end);
851 DEBUG(dbgs() << '\n');
852 }
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000853
854 if (!LiveInBlocks.empty())
855 updateSSA();
856
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000857 return Skipped;
858}
859
Jakob Stoklund Olesene2dc0c92011-03-02 23:05:16 +0000860void SplitEditor::extendPHIKillRanges() {
861 // Extend live ranges to be live-out for successor PHI values.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000862 for (LiveInterval::const_vni_iterator I = Edit->getParent().vni_begin(),
863 E = Edit->getParent().vni_end(); I != E; ++I) {
Jakob Stoklund Olesene2dc0c92011-03-02 23:05:16 +0000864 const VNInfo *PHIVNI = *I;
865 if (PHIVNI->isUnused() || !PHIVNI->isPHIDef())
866 continue;
867 unsigned RegIdx = RegAssign.lookup(PHIVNI->def);
868 MachineBasicBlock *MBB = LIS.getMBBFromIndex(PHIVNI->def);
869 for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
870 PE = MBB->pred_end(); PI != PE; ++PI) {
871 SlotIndex End = LIS.getMBBEndIdx(*PI).getPrevSlot();
872 // The predecessor may not have a live-out value. That is OK, like an
873 // undef PHI operand.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000874 if (Edit->getParent().liveAt(End)) {
Jakob Stoklund Olesene2dc0c92011-03-02 23:05:16 +0000875 assert(RegAssign.lookup(End) == RegIdx &&
876 "Different register assignment in phi predecessor");
877 extendRange(RegIdx, End);
878 }
879 }
880 }
881}
882
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000883/// rewriteAssigned - Rewrite all uses of Edit->getReg().
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000884void SplitEditor::rewriteAssigned(bool ExtendRanges) {
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000885 for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Edit->getReg()),
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000886 RE = MRI.reg_end(); RI != RE;) {
Jakob Stoklund Olesen74669272010-10-08 23:42:21 +0000887 MachineOperand &MO = RI.getOperand();
888 MachineInstr *MI = MO.getParent();
889 ++RI;
Eric Christopher0f438112011-02-03 06:18:29 +0000890 // LiveDebugVariables should have handled all DBG_VALUE instructions.
Jakob Stoklund Olesen74669272010-10-08 23:42:21 +0000891 if (MI->isDebugValue()) {
892 DEBUG(dbgs() << "Zapping " << *MI);
Jakob Stoklund Olesen74669272010-10-08 23:42:21 +0000893 MO.setReg(0);
894 continue;
895 }
Jakob Stoklund Olesena372d162011-02-09 21:52:09 +0000896
897 // <undef> operands don't really read the register, so just assign them to
898 // the complement.
899 if (MO.isUse() && MO.isUndef()) {
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000900 MO.setReg(Edit->get(0)->reg);
Jakob Stoklund Olesena372d162011-02-09 21:52:09 +0000901 continue;
902 }
903
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +0000904 SlotIndex Idx = LIS.getInstructionIndex(MI);
Jakob Stoklund Olesen7cec1792011-03-18 03:06:02 +0000905 if (MO.isDef())
906 Idx = MO.isEarlyClobber() ? Idx.getUseIndex() : Idx.getDefIndex();
Eric Christopher0f438112011-02-03 06:18:29 +0000907
908 // Rewrite to the mapped register at Idx.
909 unsigned RegIdx = RegAssign.lookup(Idx);
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000910 MO.setReg(Edit->get(RegIdx)->reg);
Eric Christopher0f438112011-02-03 06:18:29 +0000911 DEBUG(dbgs() << " rewr BB#" << MI->getParent()->getNumber() << '\t'
912 << Idx << ':' << RegIdx << '\t' << *MI);
913
Jakob Stoklund Olesen7cec1792011-03-18 03:06:02 +0000914 // Extend liveness to Idx if the instruction reads reg.
915 if (!ExtendRanges)
916 continue;
917
918 // Skip instructions that don't read Reg.
919 if (MO.isDef()) {
920 if (!MO.getSubReg() && !MO.isEarlyClobber())
921 continue;
922 // We may wan't to extend a live range for a partial redef, or for a use
923 // tied to an early clobber.
924 Idx = Idx.getPrevSlot();
925 if (!Edit->getParent().liveAt(Idx))
926 continue;
927 } else
928 Idx = Idx.getUseIndex();
929
930 extendRange(RegIdx, Idx);
Jakob Stoklund Olesen74669272010-10-08 23:42:21 +0000931 }
932}
933
Jakob Stoklund Olesen58817992011-03-08 22:46:11 +0000934void SplitEditor::deleteRematVictims() {
935 SmallVector<MachineInstr*, 8> Dead;
Jakob Stoklund Olesen2dc455a2011-03-20 19:46:23 +0000936 for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I){
937 LiveInterval *LI = *I;
938 for (LiveInterval::const_iterator LII = LI->begin(), LIE = LI->end();
939 LII != LIE; ++LII) {
940 // Dead defs end at the store slot.
941 if (LII->end != LII->valno->def.getNextSlot())
942 continue;
943 MachineInstr *MI = LIS.getInstructionFromIndex(LII->valno->def);
944 assert(MI && "Missing instruction for dead def");
945 MI->addRegisterDead(LI->reg, &TRI);
Jakob Stoklund Olesen58817992011-03-08 22:46:11 +0000946
Jakob Stoklund Olesen2dc455a2011-03-20 19:46:23 +0000947 if (!MI->allDefsAreDead())
948 continue;
Jakob Stoklund Olesen58817992011-03-08 22:46:11 +0000949
Jakob Stoklund Olesen2dc455a2011-03-20 19:46:23 +0000950 DEBUG(dbgs() << "All defs dead: " << *MI);
951 Dead.push_back(MI);
952 }
Jakob Stoklund Olesen58817992011-03-08 22:46:11 +0000953 }
954
955 if (Dead.empty())
956 return;
957
Jakob Stoklund Olesen6a3dbd32011-03-17 20:37:07 +0000958 Edit->eliminateDeadDefs(Dead, LIS, VRM, TII);
Jakob Stoklund Olesen58817992011-03-08 22:46:11 +0000959}
960
Jakob Stoklund Olesen59280462011-04-21 18:38:15 +0000961void SplitEditor::finish(SmallVectorImpl<unsigned> *LRMap) {
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000962 ++NumFinished;
Eric Christopher463a2972011-02-03 05:40:54 +0000963
Eric Christopher0f438112011-02-03 06:18:29 +0000964 // At this point, the live intervals in Edit contain VNInfos corresponding to
965 // the inserted copies.
966
967 // Add the original defs from the parent interval.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000968 for (LiveInterval::const_vni_iterator I = Edit->getParent().vni_begin(),
969 E = Edit->getParent().vni_end(); I != E; ++I) {
Eric Christopher0f438112011-02-03 06:18:29 +0000970 const VNInfo *ParentVNI = *I;
Jakob Stoklund Olesen9ecd1e72011-02-04 00:59:23 +0000971 if (ParentVNI->isUnused())
972 continue;
Jakob Stoklund Olesen670ccd12011-03-01 23:14:53 +0000973 unsigned RegIdx = RegAssign.lookup(ParentVNI->def);
Jakob Stoklund Olesen29ef8752011-03-15 21:13:22 +0000974 VNInfo *VNI = defValue(RegIdx, ParentVNI, ParentVNI->def);
975 VNI->setIsPHIDef(ParentVNI->isPHIDef());
976 VNI->setCopy(ParentVNI->getCopy());
977
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000978 // Mark rematted values as complex everywhere to force liveness computation.
979 // The new live ranges may be truncated.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000980 if (Edit->didRematerialize(ParentVNI))
981 for (unsigned i = 0, e = Edit->size(); i != e; ++i)
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000982 markComplexMapped(i, ParentVNI);
Eric Christopher0f438112011-02-03 06:18:29 +0000983 }
984
985#ifndef NDEBUG
986 // Every new interval must have a def by now, otherwise the split is bogus.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +0000987 for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I)
Eric Christopher0f438112011-02-03 06:18:29 +0000988 assert((*I)->hasAtLeastOneValue() && "Split interval has no value");
989#endif
990
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000991 // Transfer the simply mapped values, check if any are skipped.
992 bool Skipped = transferValues();
993 if (Skipped)
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000994 extendPHIKillRanges();
995 else
996 ++NumSimple;
Eric Christopher0f438112011-02-03 06:18:29 +0000997
Jakob Stoklund Olesen46703532011-03-02 23:05:19 +0000998 // Rewrite virtual registers, possibly extending ranges.
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +0000999 rewriteAssigned(Skipped);
Eric Christopher0f438112011-02-03 06:18:29 +00001000
Jakob Stoklund Olesen58817992011-03-08 22:46:11 +00001001 // Delete defs that were rematted everywhere.
Jakob Stoklund Olesen44b7ae22011-04-15 17:24:49 +00001002 if (Skipped)
Jakob Stoklund Olesen58817992011-03-08 22:46:11 +00001003 deleteRematVictims();
Jakob Stoklund Olesen5fa42a42010-09-21 22:32:21 +00001004
Jakob Stoklund Olesen0253df92010-10-07 23:34:34 +00001005 // Get rid of unused values and set phi-kill flags.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +00001006 for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I)
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +00001007 (*I)->RenumberValues(LIS);
Jakob Stoklund Olesen5fa42a42010-09-21 22:32:21 +00001008
Jakob Stoklund Olesen59280462011-04-21 18:38:15 +00001009 // Provide a reverse mapping from original indices to Edit ranges.
1010 if (LRMap) {
1011 LRMap->clear();
1012 for (unsigned i = 0, e = Edit->size(); i != e; ++i)
1013 LRMap->push_back(i);
1014 }
1015
Jakob Stoklund Olesen3a0e0712010-10-26 22:36:09 +00001016 // Now check if any registers were separated into multiple components.
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +00001017 ConnectedVNInfoEqClasses ConEQ(LIS);
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +00001018 for (unsigned i = 0, e = Edit->size(); i != e; ++i) {
Jakob Stoklund Olesen3a0e0712010-10-26 22:36:09 +00001019 // Don't use iterators, they are invalidated by create() below.
Jakob Stoklund Olesena2cae582011-03-02 23:31:50 +00001020 LiveInterval *li = Edit->get(i);
Jakob Stoklund Olesen3a0e0712010-10-26 22:36:09 +00001021 unsigned NumComp = ConEQ.Classify(li);
1022 if (NumComp <= 1)
1023 continue;
1024 DEBUG(dbgs() << " " << NumComp << " components: " << *li << '\n');
1025 SmallVector<LiveInterval*, 8> dups;
1026 dups.push_back(li);
Matt Beaumont-Gayae5fbee2011-04-21 19:46:23 +00001027 for (unsigned j = 1; j != NumComp; ++j)
Jakob Stoklund Olesen6a3dbd32011-03-17 20:37:07 +00001028 dups.push_back(&Edit->create(LIS, VRM));
Jakob Stoklund Olesen22542272011-03-17 00:23:45 +00001029 ConEQ.Distribute(&dups[0], MRI);
Jakob Stoklund Olesen59280462011-04-21 18:38:15 +00001030 // The new intervals all map back to i.
1031 if (LRMap)
1032 LRMap->resize(Edit->size(), i);
Jakob Stoklund Olesen3a0e0712010-10-26 22:36:09 +00001033 }
1034
Jakob Stoklund Olesen08e93b12010-08-10 17:07:22 +00001035 // Calculate spill weight and allocation hints for new intervals.
Jakob Stoklund Olesen6094bd82011-03-29 21:20:19 +00001036 Edit->calculateRegClassAndHint(VRM.getMachineFunction(), LIS, SA.Loops);
Jakob Stoklund Olesen59280462011-04-21 18:38:15 +00001037
1038 assert(!LRMap || LRMap->size() == Edit->size());
Jakob Stoklund Olesenf0179002010-07-26 23:44:11 +00001039}
1040
1041
Jakob Stoklund Olesen8ae02632010-07-20 15:41:07 +00001042//===----------------------------------------------------------------------===//
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +00001043// Single Block Splitting
1044//===----------------------------------------------------------------------===//
1045
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +00001046/// getMultiUseBlocks - if CurLI has more than one use in a basic block, it
1047/// may be an advantage to split CurLI for the duration of the block.
Jakob Stoklund Olesen2bfb3242010-10-22 22:48:56 +00001048bool SplitAnalysis::getMultiUseBlocks(BlockPtrSet &Blocks) {
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +00001049 // If CurLI is local to one block, there is no point to splitting it.
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +00001050 if (UseBlocks.size() <= 1)
Jakob Stoklund Olesen2bfb3242010-10-22 22:48:56 +00001051 return false;
1052 // Add blocks with multiple uses.
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +00001053 for (unsigned i = 0, e = UseBlocks.size(); i != e; ++i) {
1054 const BlockInfo &BI = UseBlocks[i];
1055 if (BI.FirstUse == BI.LastUse)
Jakob Stoklund Olesen9b057772011-02-09 23:30:25 +00001056 continue;
1057 Blocks.insert(BI.MBB);
1058 }
Jakob Stoklund Olesen2bfb3242010-10-22 22:48:56 +00001059 return !Blocks.empty();
1060}
1061
Jakob Stoklund Olesenfd5c5132011-04-12 19:32:53 +00001062void SplitEditor::splitSingleBlock(const SplitAnalysis::BlockInfo &BI) {
1063 openIntv();
1064 SlotIndex LastSplitPoint = SA.getLastSplitPoint(BI.MBB->getNumber());
1065 SlotIndex SegStart = enterIntvBefore(std::min(BI.FirstUse,
1066 LastSplitPoint));
1067 if (!BI.LiveOut || BI.LastUse < LastSplitPoint) {
1068 useIntv(SegStart, leaveIntvAfter(BI.LastUse));
1069 } else {
1070 // The last use is after the last valid split point.
1071 SlotIndex SegStop = leaveIntvBefore(LastSplitPoint);
1072 useIntv(SegStart, SegStop);
1073 overlapIntv(SegStop, BI.LastUse);
1074 }
Jakob Stoklund Olesenfd5c5132011-04-12 19:32:53 +00001075}
1076
Jakob Stoklund Olesen07862842011-01-26 00:50:53 +00001077/// splitSingleBlocks - Split CurLI into a separate live interval inside each
Jakob Stoklund Olesen57d0f2d2010-10-05 22:19:33 +00001078/// basic block in Blocks.
1079void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) {
Jakob Stoklund Olesene1f543f2010-08-12 18:50:55 +00001080 DEBUG(dbgs() << " splitSingleBlocks for " << Blocks.size() << " blocks.\n");
Jakob Stoklund Olesendb529a82011-04-06 03:57:00 +00001081 ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA.getUseBlocks();
1082 for (unsigned i = 0; i != UseBlocks.size(); ++i) {
1083 const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
Jakob Stoklund Olesenfd5c5132011-04-12 19:32:53 +00001084 if (Blocks.count(BI.MBB))
1085 splitSingleBlock(BI);
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +00001086 }
Jakob Stoklund Olesen74669272010-10-08 23:42:21 +00001087 finish();
Jakob Stoklund Olesenf1b05f22010-08-12 17:07:14 +00001088}