1 //===- PartialInlining.cpp - Inline parts of functions --------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass performs partial inlining, typically by inlining an if statement
11 // that surrounds the body of the function.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Transforms/IPO/PartialInlining.h"
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/DenseSet.h"
18 #include "llvm/ADT/None.h"
19 #include "llvm/ADT/Optional.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/Analysis/BlockFrequencyInfo.h"
24 #include "llvm/Analysis/BranchProbabilityInfo.h"
25 #include "llvm/Analysis/InlineCost.h"
26 #include "llvm/Analysis/LoopInfo.h"
27 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
28 #include "llvm/Analysis/ProfileSummaryInfo.h"
29 #include "llvm/Analysis/TargetLibraryInfo.h"
30 #include "llvm/Analysis/TargetTransformInfo.h"
31 #include "llvm/IR/Attributes.h"
32 #include "llvm/IR/BasicBlock.h"
33 #include "llvm/IR/CFG.h"
34 #include "llvm/IR/CallSite.h"
35 #include "llvm/IR/DebugLoc.h"
36 #include "llvm/IR/DiagnosticInfo.h"
37 #include "llvm/IR/Dominators.h"
38 #include "llvm/IR/Function.h"
39 #include "llvm/IR/InstrTypes.h"
40 #include "llvm/IR/Instruction.h"
41 #include "llvm/IR/Instructions.h"
42 #include "llvm/IR/IntrinsicInst.h"
43 #include "llvm/IR/Intrinsics.h"
44 #include "llvm/IR/Module.h"
45 #include "llvm/IR/User.h"
46 #include "llvm/Pass.h"
47 #include "llvm/Support/BlockFrequency.h"
48 #include "llvm/Support/BranchProbability.h"
49 #include "llvm/Support/Casting.h"
50 #include "llvm/Support/CommandLine.h"
51 #include "llvm/Support/ErrorHandling.h"
52 #include "llvm/Transforms/IPO.h"
53 #include "llvm/Transforms/Utils/Cloning.h"
54 #include "llvm/Transforms/Utils/CodeExtractor.h"
55 #include "llvm/Transforms/Utils/ValueMapper.h"
67 #define DEBUG_TYPE "partial-inlining"
69 STATISTIC(NumPartialInlined,
70 "Number of callsites functions partially inlined into.");
71 STATISTIC(NumColdOutlinePartialInlined, "Number of times functions with "
72 "cold outlined regions were partially "
73 "inlined into its caller(s).");
74 STATISTIC(NumColdRegionsFound,
75 "Number of cold single entry/exit regions found.");
76 STATISTIC(NumColdRegionsOutlined,
77 "Number of cold single entry/exit regions outlined.");
79 // Command line option to disable partial-inlining. The default is false:
81 DisablePartialInlining("disable-partial-inlining", cl::init(false),
82 cl::Hidden, cl::desc("Disable partial inlining"));
83 // Command line option to disable multi-region partial-inlining. The default is
85 static cl::opt<bool> DisableMultiRegionPartialInline(
86 "disable-mr-partial-inlining", cl::init(false), cl::Hidden,
87 cl::desc("Disable multi-region partial inlining"));
89 // Command line option to force outlining in regions with live exit variables.
90 // The default is false:
92 ForceLiveExit("pi-force-live-exit-outline", cl::init(false), cl::Hidden,
93 cl::desc("Force outline regions with live exits"));
95 // Command line option to enable marking outline functions with Cold Calling
96 // Convention. The default is false:
98 MarkOutlinedColdCC("pi-mark-coldcc", cl::init(false), cl::Hidden,
99 cl::desc("Mark outline function calls with ColdCC"));
102 // Command line option to debug partial-inlining. The default is none:
103 static cl::opt<bool> TracePartialInlining("trace-partial-inlining",
104 cl::init(false), cl::Hidden,
105 cl::desc("Trace partial inlining."));
108 // This is an option used by testing:
109 static cl::opt<bool> SkipCostAnalysis("skip-partial-inlining-cost-analysis",
110 cl::init(false), cl::ZeroOrMore,
112 cl::desc("Skip Cost Analysis"));
113 // Used to determine if a cold region is worth outlining based on
114 // its inlining cost compared to the original function. Default is set at 10%.
115 // ie. if the cold region reduces the inlining cost of the original function by
117 static cl::opt<float> MinRegionSizeRatio(
118 "min-region-size-ratio", cl::init(0.1), cl::Hidden,
119 cl::desc("Minimum ratio comparing relative sizes of each "
120 "outline candidate and original function"));
121 // Used to tune the minimum number of execution counts needed in the predecessor
122 // block to the cold edge. ie. confidence interval.
123 static cl::opt<unsigned>
124 MinBlockCounterExecution("min-block-execution", cl::init(100), cl::Hidden,
125 cl::desc("Minimum block executions to consider "
126 "its BranchProbabilityInfo valid"));
127 // Used to determine when an edge is considered cold. Default is set to 10%. ie.
128 // if the branch probability is 10% or less, then it is deemed as 'cold'.
129 static cl::opt<float> ColdBranchRatio(
130 "cold-branch-ratio", cl::init(0.1), cl::Hidden,
131 cl::desc("Minimum BranchProbability to consider a region cold."));
133 static cl::opt<unsigned> MaxNumInlineBlocks(
134 "max-num-inline-blocks", cl::init(5), cl::Hidden,
135 cl::desc("Max number of blocks to be partially inlined"));
137 // Command line option to set the maximum number of partial inlining allowed
138 // for the module. The default value of -1 means no limit.
139 static cl::opt<int> MaxNumPartialInlining(
140 "max-partial-inlining", cl::init(-1), cl::Hidden, cl::ZeroOrMore,
141 cl::desc("Max number of partial inlining. The default is unlimited"));
143 // Used only when PGO or user annotated branch data is absent. It is
144 // the least value that is used to weigh the outline region. If BFI
145 // produces larger value, the BFI value will be used.
147 OutlineRegionFreqPercent("outline-region-freq-percent", cl::init(75),
148 cl::Hidden, cl::ZeroOrMore,
149 cl::desc("Relative frequency of outline region to "
152 static cl::opt<unsigned> ExtraOutliningPenalty(
153 "partial-inlining-extra-penalty", cl::init(0), cl::Hidden,
154 cl::desc("A debug option to add additional penalty to the computed one."));
158 struct FunctionOutliningInfo {
159 FunctionOutliningInfo() = default;
161 // Returns the number of blocks to be inlined including all blocks
162 // in Entries and one return block.
163 unsigned GetNumInlinedBlocks() const { return Entries.size() + 1; }
165 // A set of blocks including the function entry that guard
166 // the region to be outlined.
167 SmallVector<BasicBlock *, 4> Entries;
169 // The return block that is not included in the outlined region.
170 BasicBlock *ReturnBlock = nullptr;
172 // The dominating block of the region to be outlined.
173 BasicBlock *NonReturnBlock = nullptr;
175 // The set of blocks in Entries that that are predecessors to ReturnBlock
176 SmallVector<BasicBlock *, 4> ReturnBlockPreds;
179 struct FunctionOutliningMultiRegionInfo {
180 FunctionOutliningMultiRegionInfo()
183 // Container for outline regions
184 struct OutlineRegionInfo {
185 OutlineRegionInfo(SmallVector<BasicBlock *, 8> Region,
186 BasicBlock *EntryBlock, BasicBlock *ExitBlock,
187 BasicBlock *ReturnBlock)
188 : Region(Region), EntryBlock(EntryBlock), ExitBlock(ExitBlock),
189 ReturnBlock(ReturnBlock) {}
190 SmallVector<BasicBlock *, 8> Region;
191 BasicBlock *EntryBlock;
192 BasicBlock *ExitBlock;
193 BasicBlock *ReturnBlock;
196 SmallVector<OutlineRegionInfo, 4> ORI;
199 struct PartialInlinerImpl {
202 std::function<AssumptionCache &(Function &)> *GetAC,
203 std::function<TargetTransformInfo &(Function &)> *GTTI,
204 Optional<function_ref<BlockFrequencyInfo &(Function &)>> GBFI,
205 ProfileSummaryInfo *ProfSI,
206 std::function<OptimizationRemarkEmitter &(Function &)> *GORE)
207 : GetAssumptionCache(GetAC), GetTTI(GTTI), GetBFI(GBFI), PSI(ProfSI),
211 // Main part of the transformation that calls helper functions to find
212 // outlining candidates, clone & outline the function, and attempt to
213 // partially inline the resulting function. Returns true if
214 // inlining was successful, false otherwise. Also returns the outline
215 // function (only if we partially inlined early returns) as there is a
216 // possibility to further "peel" early return statements that were left in the
217 // outline function due to code size.
218 std::pair<bool, Function *> unswitchFunction(Function *F);
220 // This class speculatively clones the the function to be partial inlined.
221 // At the end of partial inlining, the remaining callsites to the cloned
222 // function that are not partially inlined will be fixed up to reference
223 // the original function, and the cloned function will be erased.
224 struct FunctionCloner {
225 // Two constructors, one for single region outlining, the other for
226 // multi-region outlining.
227 FunctionCloner(Function *F, FunctionOutliningInfo *OI,
228 OptimizationRemarkEmitter &ORE);
229 FunctionCloner(Function *F, FunctionOutliningMultiRegionInfo *OMRI,
230 OptimizationRemarkEmitter &ORE);
233 // Prepare for function outlining: making sure there is only
234 // one incoming edge from the extracted/outlined region to
236 void NormalizeReturnBlock();
238 // Do function outlining for cold regions.
239 bool doMultiRegionFunctionOutlining();
240 // Do function outlining for region after early return block(s).
241 // NOTE: For vararg functions that do the vararg handling in the outlined
242 // function, we temporarily generate IR that does not properly
243 // forward varargs to the outlined function. Calling InlineFunction
244 // will update calls to the outlined functions to properly forward
246 Function *doSingleRegionFunctionOutlining();
248 Function *OrigFunc = nullptr;
249 Function *ClonedFunc = nullptr;
251 typedef std::pair<Function *, BasicBlock *> FuncBodyCallerPair;
252 // Keep track of Outlined Functions and the basic block they're called from.
253 SmallVector<FuncBodyCallerPair, 4> OutlinedFunctions;
255 // ClonedFunc is inlined in one of its callers after function
257 bool IsFunctionInlined = false;
258 // The cost of the region to be outlined.
259 int OutlinedRegionCost = 0;
260 // ClonedOI is specific to outlining non-early return blocks.
261 std::unique_ptr<FunctionOutliningInfo> ClonedOI = nullptr;
262 // ClonedOMRI is specific to outlining cold regions.
263 std::unique_ptr<FunctionOutliningMultiRegionInfo> ClonedOMRI = nullptr;
264 std::unique_ptr<BlockFrequencyInfo> ClonedFuncBFI = nullptr;
265 OptimizationRemarkEmitter &ORE;
269 int NumPartialInlining = 0;
270 std::function<AssumptionCache &(Function &)> *GetAssumptionCache;
271 std::function<TargetTransformInfo &(Function &)> *GetTTI;
272 Optional<function_ref<BlockFrequencyInfo &(Function &)>> GetBFI;
273 ProfileSummaryInfo *PSI;
274 std::function<OptimizationRemarkEmitter &(Function &)> *GetORE;
276 // Return the frequency of the OutlininingBB relative to F's entry point.
277 // The result is no larger than 1 and is represented using BP.
278 // (Note that the outlined region's 'head' block can only have incoming
279 // edges from the guarding entry blocks).
280 BranchProbability getOutliningCallBBRelativeFreq(FunctionCloner &Cloner);
282 // Return true if the callee of CS should be partially inlined with
284 bool shouldPartialInline(CallSite CS, FunctionCloner &Cloner,
285 BlockFrequency WeightedOutliningRcost);
287 // Try to inline DuplicateFunction (cloned from F with call to
288 // the OutlinedFunction into its callers. Return true
289 // if there is any successful inlining.
290 bool tryPartialInline(FunctionCloner &Cloner);
292 // Compute the mapping from use site of DuplicationFunction to the enclosing
293 // BB's profile count.
294 void computeCallsiteToProfCountMap(Function *DuplicateFunction,
295 DenseMap<User *, uint64_t> &SiteCountMap);
297 bool IsLimitReached() {
298 return (MaxNumPartialInlining != -1 &&
299 NumPartialInlining >= MaxNumPartialInlining);
302 static CallSite getCallSite(User *U) {
304 if (CallInst *CI = dyn_cast<CallInst>(U))
306 else if (InvokeInst *II = dyn_cast<InvokeInst>(U))
309 llvm_unreachable("All uses must be calls");
313 static CallSite getOneCallSiteTo(Function *F) {
314 User *User = *F->user_begin();
315 return getCallSite(User);
318 std::tuple<DebugLoc, BasicBlock *> getOneDebugLoc(Function *F) {
319 CallSite CS = getOneCallSiteTo(F);
320 DebugLoc DLoc = CS.getInstruction()->getDebugLoc();
321 BasicBlock *Block = CS.getParent();
322 return std::make_tuple(DLoc, Block);
325 // Returns the costs associated with function outlining:
326 // - The first value is the non-weighted runtime cost for making the call
327 // to the outlined function, including the addtional setup cost in the
328 // outlined function itself;
329 // - The second value is the estimated size of the new call sequence in
330 // basic block Cloner.OutliningCallBB;
331 std::tuple<int, int> computeOutliningCosts(FunctionCloner &Cloner);
333 // Compute the 'InlineCost' of block BB. InlineCost is a proxy used to
334 // approximate both the size and runtime cost (Note that in the current
335 // inline cost analysis, there is no clear distinction there either).
336 static int computeBBInlineCost(BasicBlock *BB);
338 std::unique_ptr<FunctionOutliningInfo> computeOutliningInfo(Function *F);
339 std::unique_ptr<FunctionOutliningMultiRegionInfo>
340 computeOutliningColdRegionsInfo(Function *F);
343 struct PartialInlinerLegacyPass : public ModulePass {
344 static char ID; // Pass identification, replacement for typeid
346 PartialInlinerLegacyPass() : ModulePass(ID) {
347 initializePartialInlinerLegacyPassPass(*PassRegistry::getPassRegistry());
350 void getAnalysisUsage(AnalysisUsage &AU) const override {
351 AU.addRequired<AssumptionCacheTracker>();
352 AU.addRequired<ProfileSummaryInfoWrapperPass>();
353 AU.addRequired<TargetTransformInfoWrapperPass>();
356 bool runOnModule(Module &M) override {
360 AssumptionCacheTracker *ACT = &getAnalysis<AssumptionCacheTracker>();
361 TargetTransformInfoWrapperPass *TTIWP =
362 &getAnalysis<TargetTransformInfoWrapperPass>();
363 ProfileSummaryInfo *PSI =
364 getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
365 std::unique_ptr<OptimizationRemarkEmitter> UPORE;
367 std::function<AssumptionCache &(Function &)> GetAssumptionCache =
368 [&ACT](Function &F) -> AssumptionCache & {
369 return ACT->getAssumptionCache(F);
372 std::function<TargetTransformInfo &(Function &)> GetTTI =
373 [&TTIWP](Function &F) -> TargetTransformInfo & {
374 return TTIWP->getTTI(F);
377 std::function<OptimizationRemarkEmitter &(Function &)> GetORE =
378 [&UPORE](Function &F) -> OptimizationRemarkEmitter & {
379 UPORE.reset(new OptimizationRemarkEmitter(&F));
383 return PartialInlinerImpl(&GetAssumptionCache, &GetTTI, NoneType::None, PSI,
389 } // end anonymous namespace
391 std::unique_ptr<FunctionOutliningMultiRegionInfo>
392 PartialInlinerImpl::computeOutliningColdRegionsInfo(Function *F) {
393 BasicBlock *EntryBlock = &F->front();
395 DominatorTree DT(*F);
397 BranchProbabilityInfo BPI(*F, LI);
398 std::unique_ptr<BlockFrequencyInfo> ScopedBFI;
399 BlockFrequencyInfo *BFI;
401 ScopedBFI.reset(new BlockFrequencyInfo(*F, BPI, LI));
402 BFI = ScopedBFI.get();
404 BFI = &(*GetBFI)(*F);
406 auto &ORE = (*GetORE)(*F);
408 // Return if we don't have profiling information.
409 if (!PSI->hasInstrumentationProfile())
410 return std::unique_ptr<FunctionOutliningMultiRegionInfo>();
412 std::unique_ptr<FunctionOutliningMultiRegionInfo> OutliningInfo =
413 llvm::make_unique<FunctionOutliningMultiRegionInfo>();
415 auto IsSingleEntry = [](SmallVectorImpl<BasicBlock *> &BlockList) {
416 BasicBlock *Dom = BlockList.front();
417 return BlockList.size() > 1 &&
418 std::distance(pred_begin(Dom), pred_end(Dom)) == 1;
422 [&ORE](SmallVectorImpl<BasicBlock *> &BlockList) -> BasicBlock * {
423 BasicBlock *ExitBlock = nullptr;
424 for (auto *Block : BlockList) {
425 for (auto SI = succ_begin(Block); SI != succ_end(Block); ++SI) {
426 if (!is_contained(BlockList, *SI)) {
429 return OptimizationRemarkMissed(DEBUG_TYPE, "MultiExitRegion",
431 << "Region dominated by "
432 << ore::NV("Block", BlockList.front()->getName())
433 << " has more than one region exit edge.";
444 auto BBProfileCount = [BFI](BasicBlock *BB) {
445 return BFI->getBlockProfileCount(BB)
446 ? BFI->getBlockProfileCount(BB).getValue()
450 // Use the same computeBBInlineCost function to compute the cost savings of
451 // the outlining the candidate region.
452 int OverallFunctionCost = 0;
454 OverallFunctionCost += computeBBInlineCost(&BB);
457 if (TracePartialInlining)
458 dbgs() << "OverallFunctionCost = " << OverallFunctionCost << "\n";
460 int MinOutlineRegionCost =
461 static_cast<int>(OverallFunctionCost * MinRegionSizeRatio);
462 BranchProbability MinBranchProbability(
463 static_cast<int>(ColdBranchRatio * MinBlockCounterExecution),
464 MinBlockCounterExecution);
465 bool ColdCandidateFound = false;
466 BasicBlock *CurrEntry = EntryBlock;
467 std::vector<BasicBlock *> DFS;
468 DenseMap<BasicBlock *, bool> VisitedMap;
469 DFS.push_back(CurrEntry);
470 VisitedMap[CurrEntry] = true;
471 // Use Depth First Search on the basic blocks to find CFG edges that are
473 // Cold regions considered must also have its inline cost compared to the
474 // overall inline cost of the original function. The region is outlined only
475 // if it reduced the inline cost of the function by 'MinOutlineRegionCost' or
477 while (!DFS.empty()) {
478 auto *thisBB = DFS.back();
480 // Only consider regions with predecessor blocks that are considered
481 // not-cold (default: part of the top 99.99% of all block counters)
482 // AND greater than our minimum block execution count (default: 100).
483 if (PSI->isColdBB(thisBB, BFI) ||
484 BBProfileCount(thisBB) < MinBlockCounterExecution)
486 for (auto SI = succ_begin(thisBB); SI != succ_end(thisBB); ++SI) {
489 VisitedMap[*SI] = true;
491 // If branch isn't cold, we skip to the next one.
492 BranchProbability SuccProb = BPI.getEdgeProbability(thisBB, *SI);
493 if (SuccProb > MinBranchProbability)
496 if (TracePartialInlining) {
497 dbgs() << "Found cold edge: " << thisBB->getName() << "->"
498 << (*SI)->getName() << "\nBranch Probability = " << SuccProb
502 SmallVector<BasicBlock *, 8> DominateVector;
503 DT.getDescendants(*SI, DominateVector);
504 // We can only outline single entry regions (for now).
505 if (!IsSingleEntry(DominateVector))
507 BasicBlock *ExitBlock = nullptr;
508 // We can only outline single exit regions (for now).
509 if (!(ExitBlock = IsSingleExit(DominateVector)))
511 int OutlineRegionCost = 0;
512 for (auto *BB : DominateVector)
513 OutlineRegionCost += computeBBInlineCost(BB);
516 if (TracePartialInlining)
517 dbgs() << "OutlineRegionCost = " << OutlineRegionCost << "\n";
520 if (OutlineRegionCost < MinOutlineRegionCost) {
522 return OptimizationRemarkAnalysis(DEBUG_TYPE, "TooCostly",
524 << ore::NV("Callee", F) << " inline cost-savings smaller than "
525 << ore::NV("Cost", MinOutlineRegionCost);
529 // For now, ignore blocks that belong to a SISE region that is a
530 // candidate for outlining. In the future, we may want to look
531 // at inner regions because the outer region may have live-exit
533 for (auto *BB : DominateVector)
534 VisitedMap[BB] = true;
535 // ReturnBlock here means the block after the outline call
536 BasicBlock *ReturnBlock = ExitBlock->getSingleSuccessor();
537 // assert(ReturnBlock && "ReturnBlock is NULL somehow!");
538 FunctionOutliningMultiRegionInfo::OutlineRegionInfo RegInfo(
539 DominateVector, DominateVector.front(), ExitBlock, ReturnBlock);
540 RegInfo.Region = DominateVector;
541 OutliningInfo->ORI.push_back(RegInfo);
543 if (TracePartialInlining) {
544 dbgs() << "Found Cold Candidate starting at block: "
545 << DominateVector.front()->getName() << "\n";
548 ColdCandidateFound = true;
549 NumColdRegionsFound++;
552 if (ColdCandidateFound)
553 return OutliningInfo;
555 return std::unique_ptr<FunctionOutliningMultiRegionInfo>();
558 std::unique_ptr<FunctionOutliningInfo>
559 PartialInlinerImpl::computeOutliningInfo(Function *F) {
560 BasicBlock *EntryBlock = &F->front();
561 BranchInst *BR = dyn_cast<BranchInst>(EntryBlock->getTerminator());
562 if (!BR || BR->isUnconditional())
563 return std::unique_ptr<FunctionOutliningInfo>();
565 // Returns true if Succ is BB's successor
566 auto IsSuccessor = [](BasicBlock *Succ, BasicBlock *BB) {
567 return is_contained(successors(BB), Succ);
570 auto SuccSize = [](BasicBlock *BB) {
571 return std::distance(succ_begin(BB), succ_end(BB));
574 auto IsReturnBlock = [](BasicBlock *BB) {
575 TerminatorInst *TI = BB->getTerminator();
576 return isa<ReturnInst>(TI);
579 auto GetReturnBlock = [&](BasicBlock *Succ1, BasicBlock *Succ2) {
580 if (IsReturnBlock(Succ1))
581 return std::make_tuple(Succ1, Succ2);
582 if (IsReturnBlock(Succ2))
583 return std::make_tuple(Succ2, Succ1);
585 return std::make_tuple<BasicBlock *, BasicBlock *>(nullptr, nullptr);
588 // Detect a triangular shape:
589 auto GetCommonSucc = [&](BasicBlock *Succ1, BasicBlock *Succ2) {
590 if (IsSuccessor(Succ1, Succ2))
591 return std::make_tuple(Succ1, Succ2);
592 if (IsSuccessor(Succ2, Succ1))
593 return std::make_tuple(Succ2, Succ1);
595 return std::make_tuple<BasicBlock *, BasicBlock *>(nullptr, nullptr);
598 std::unique_ptr<FunctionOutliningInfo> OutliningInfo =
599 llvm::make_unique<FunctionOutliningInfo>();
601 BasicBlock *CurrEntry = EntryBlock;
602 bool CandidateFound = false;
604 // The number of blocks to be inlined has already reached
605 // the limit. When MaxNumInlineBlocks is set to 0 or 1, this
606 // disables partial inlining for the function.
607 if (OutliningInfo->GetNumInlinedBlocks() >= MaxNumInlineBlocks)
610 if (SuccSize(CurrEntry) != 2)
613 BasicBlock *Succ1 = *succ_begin(CurrEntry);
614 BasicBlock *Succ2 = *(succ_begin(CurrEntry) + 1);
616 BasicBlock *ReturnBlock, *NonReturnBlock;
617 std::tie(ReturnBlock, NonReturnBlock) = GetReturnBlock(Succ1, Succ2);
620 OutliningInfo->Entries.push_back(CurrEntry);
621 OutliningInfo->ReturnBlock = ReturnBlock;
622 OutliningInfo->NonReturnBlock = NonReturnBlock;
623 CandidateFound = true;
627 BasicBlock *CommSucc;
628 BasicBlock *OtherSucc;
629 std::tie(CommSucc, OtherSucc) = GetCommonSucc(Succ1, Succ2);
634 OutliningInfo->Entries.push_back(CurrEntry);
635 CurrEntry = OtherSucc;
639 return std::unique_ptr<FunctionOutliningInfo>();
641 // Do sanity check of the entries: threre should not
642 // be any successors (not in the entry set) other than
643 // {ReturnBlock, NonReturnBlock}
644 assert(OutliningInfo->Entries[0] == &F->front() &&
645 "Function Entry must be the first in Entries vector");
646 DenseSet<BasicBlock *> Entries;
647 for (BasicBlock *E : OutliningInfo->Entries)
650 // Returns true of BB has Predecessor which is not
652 auto HasNonEntryPred = [Entries](BasicBlock *BB) {
653 for (auto Pred : predecessors(BB)) {
654 if (!Entries.count(Pred))
659 auto CheckAndNormalizeCandidate =
660 [Entries, HasNonEntryPred](FunctionOutliningInfo *OutliningInfo) {
661 for (BasicBlock *E : OutliningInfo->Entries) {
662 for (auto Succ : successors(E)) {
663 if (Entries.count(Succ))
665 if (Succ == OutliningInfo->ReturnBlock)
666 OutliningInfo->ReturnBlockPreds.push_back(E);
667 else if (Succ != OutliningInfo->NonReturnBlock)
670 // There should not be any outside incoming edges either:
671 if (HasNonEntryPred(E))
677 if (!CheckAndNormalizeCandidate(OutliningInfo.get()))
678 return std::unique_ptr<FunctionOutliningInfo>();
680 // Now further growing the candidate's inlining region by
681 // peeling off dominating blocks from the outlining region:
682 while (OutliningInfo->GetNumInlinedBlocks() < MaxNumInlineBlocks) {
683 BasicBlock *Cand = OutliningInfo->NonReturnBlock;
684 if (SuccSize(Cand) != 2)
687 if (HasNonEntryPred(Cand))
690 BasicBlock *Succ1 = *succ_begin(Cand);
691 BasicBlock *Succ2 = *(succ_begin(Cand) + 1);
693 BasicBlock *ReturnBlock, *NonReturnBlock;
694 std::tie(ReturnBlock, NonReturnBlock) = GetReturnBlock(Succ1, Succ2);
695 if (!ReturnBlock || ReturnBlock != OutliningInfo->ReturnBlock)
698 if (NonReturnBlock->getSinglePredecessor() != Cand)
701 // Now grow and update OutlininigInfo:
702 OutliningInfo->Entries.push_back(Cand);
703 OutliningInfo->NonReturnBlock = NonReturnBlock;
704 OutliningInfo->ReturnBlockPreds.push_back(Cand);
705 Entries.insert(Cand);
708 return OutliningInfo;
711 // Check if there is PGO data or user annoated branch data:
712 static bool hasProfileData(Function *F, FunctionOutliningInfo *OI) {
713 if (F->hasProfileData())
715 // Now check if any of the entry block has MD_prof data:
716 for (auto *E : OI->Entries) {
717 BranchInst *BR = dyn_cast<BranchInst>(E->getTerminator());
718 if (!BR || BR->isUnconditional())
721 if (BR->extractProfMetadata(T, F))
728 PartialInlinerImpl::getOutliningCallBBRelativeFreq(FunctionCloner &Cloner) {
729 BasicBlock *OutliningCallBB = Cloner.OutlinedFunctions.back().second;
731 Cloner.ClonedFuncBFI->getBlockFreq(&Cloner.ClonedFunc->getEntryBlock());
732 auto OutliningCallFreq =
733 Cloner.ClonedFuncBFI->getBlockFreq(OutliningCallBB);
734 // FIXME Hackery needed because ClonedFuncBFI is based on the function BEFORE
735 // we outlined any regions, so we may encounter situations where the
736 // OutliningCallFreq is *slightly* bigger than the EntryFreq.
737 if (OutliningCallFreq.getFrequency() > EntryFreq.getFrequency()) {
738 OutliningCallFreq = EntryFreq;
740 auto OutlineRegionRelFreq = BranchProbability::getBranchProbability(
741 OutliningCallFreq.getFrequency(), EntryFreq.getFrequency());
743 if (hasProfileData(Cloner.OrigFunc, Cloner.ClonedOI.get()))
744 return OutlineRegionRelFreq;
746 // When profile data is not available, we need to be conservative in
747 // estimating the overall savings. Static branch prediction can usually
748 // guess the branch direction right (taken/non-taken), but the guessed
749 // branch probability is usually not biased enough. In case when the
750 // outlined region is predicted to be likely, its probability needs
751 // to be made higher (more biased) to not under-estimate the cost of
752 // function outlining. On the other hand, if the outlined region
753 // is predicted to be less likely, the predicted probablity is usually
754 // higher than the actual. For instance, the actual probability of the
755 // less likely target is only 5%, but the guessed probablity can be
756 // 40%. In the latter case, there is no need for further adjustement.
757 // FIXME: add an option for this.
758 if (OutlineRegionRelFreq < BranchProbability(45, 100))
759 return OutlineRegionRelFreq;
761 OutlineRegionRelFreq = std::max(
762 OutlineRegionRelFreq, BranchProbability(OutlineRegionFreqPercent, 100));
764 return OutlineRegionRelFreq;
767 bool PartialInlinerImpl::shouldPartialInline(
768 CallSite CS, FunctionCloner &Cloner,
769 BlockFrequency WeightedOutliningRcost) {
772 if (SkipCostAnalysis)
775 Instruction *Call = CS.getInstruction();
776 Function *Callee = CS.getCalledFunction();
777 assert(Callee == Cloner.ClonedFunc);
779 Function *Caller = CS.getCaller();
780 auto &CalleeTTI = (*GetTTI)(*Callee);
781 auto &ORE = (*GetORE)(*Caller);
782 InlineCost IC = getInlineCost(CS, getInlineParams(), CalleeTTI,
783 *GetAssumptionCache, GetBFI, PSI, &ORE);
787 return OptimizationRemarkAnalysis(DEBUG_TYPE, "AlwaysInline", Call)
788 << NV("Callee", Cloner.OrigFunc)
789 << " should always be fully inlined, not partially";
796 return OptimizationRemarkMissed(DEBUG_TYPE, "NeverInline", Call)
797 << NV("Callee", Cloner.OrigFunc) << " not partially inlined into "
798 << NV("Caller", Caller)
799 << " because it should never be inlined (cost=never)";
806 return OptimizationRemarkAnalysis(DEBUG_TYPE, "TooCostly", Call)
807 << NV("Callee", Cloner.OrigFunc) << " not partially inlined into "
808 << NV("Caller", Caller) << " because too costly to inline (cost="
809 << NV("Cost", IC.getCost()) << ", threshold="
810 << NV("Threshold", IC.getCostDelta() + IC.getCost()) << ")";
814 const DataLayout &DL = Caller->getParent()->getDataLayout();
816 // The savings of eliminating the call:
817 int NonWeightedSavings = getCallsiteCost(CS, DL);
818 BlockFrequency NormWeightedSavings(NonWeightedSavings);
820 // Weighted saving is smaller than weighted cost, return false
821 if (NormWeightedSavings < WeightedOutliningRcost) {
823 return OptimizationRemarkAnalysis(DEBUG_TYPE, "OutliningCallcostTooHigh",
825 << NV("Callee", Cloner.OrigFunc) << " not partially inlined into "
826 << NV("Caller", Caller) << " runtime overhead (overhead="
827 << NV("Overhead", (unsigned)WeightedOutliningRcost.getFrequency())
829 << NV("Savings", (unsigned)NormWeightedSavings.getFrequency())
831 << " of making the outlined call is too high";
838 return OptimizationRemarkAnalysis(DEBUG_TYPE, "CanBePartiallyInlined", Call)
839 << NV("Callee", Cloner.OrigFunc) << " can be partially inlined into "
840 << NV("Caller", Caller) << " with cost=" << NV("Cost", IC.getCost())
842 << NV("Threshold", IC.getCostDelta() + IC.getCost()) << ")";
847 // TODO: Ideally we should share Inliner's InlineCost Analysis code.
848 // For now use a simplified version. The returned 'InlineCost' will be used
849 // to esimate the size cost as well as runtime cost of the BB.
850 int PartialInlinerImpl::computeBBInlineCost(BasicBlock *BB) {
852 const DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
853 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
854 if (isa<DbgInfoIntrinsic>(I))
857 switch (I->getOpcode()) {
858 case Instruction::BitCast:
859 case Instruction::PtrToInt:
860 case Instruction::IntToPtr:
861 case Instruction::Alloca:
863 case Instruction::GetElementPtr:
864 if (cast<GetElementPtrInst>(I)->hasAllZeroIndices())
871 IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(I);
873 if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_start ||
874 IntrInst->getIntrinsicID() == Intrinsic::lifetime_end)
878 if (CallInst *CI = dyn_cast<CallInst>(I)) {
879 InlineCost += getCallsiteCost(CallSite(CI), DL);
883 if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
884 InlineCost += getCallsiteCost(CallSite(II), DL);
888 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
889 InlineCost += (SI->getNumCases() + 1) * InlineConstants::InstrCost;
892 InlineCost += InlineConstants::InstrCost;
898 PartialInlinerImpl::computeOutliningCosts(FunctionCloner &Cloner) {
899 int OutliningFuncCallCost = 0, OutlinedFunctionCost = 0;
900 for (auto FuncBBPair : Cloner.OutlinedFunctions) {
901 Function *OutlinedFunc = FuncBBPair.first;
902 BasicBlock* OutliningCallBB = FuncBBPair.second;
903 // Now compute the cost of the call sequence to the outlined function
904 // 'OutlinedFunction' in BB 'OutliningCallBB':
905 OutliningFuncCallCost += computeBBInlineCost(OutliningCallBB);
907 // Now compute the cost of the extracted/outlined function itself:
908 for (BasicBlock &BB : *OutlinedFunc)
909 OutlinedFunctionCost += computeBBInlineCost(&BB);
911 assert(OutlinedFunctionCost >= Cloner.OutlinedRegionCost &&
912 "Outlined function cost should be no less than the outlined region");
914 // The code extractor introduces a new root and exit stub blocks with
915 // additional unconditional branches. Those branches will be eliminated
916 // later with bb layout. The cost should be adjusted accordingly:
917 OutlinedFunctionCost -=
918 2 * InlineConstants::InstrCost * Cloner.OutlinedFunctions.size();
920 int OutliningRuntimeOverhead =
921 OutliningFuncCallCost +
922 (OutlinedFunctionCost - Cloner.OutlinedRegionCost) +
923 ExtraOutliningPenalty;
925 return std::make_tuple(OutliningFuncCallCost, OutliningRuntimeOverhead);
928 // Create the callsite to profile count map which is
929 // used to update the original function's entry count,
930 // after the function is partially inlined into the callsite.
931 void PartialInlinerImpl::computeCallsiteToProfCountMap(
932 Function *DuplicateFunction,
933 DenseMap<User *, uint64_t> &CallSiteToProfCountMap) {
934 std::vector<User *> Users(DuplicateFunction->user_begin(),
935 DuplicateFunction->user_end());
936 Function *CurrentCaller = nullptr;
937 std::unique_ptr<BlockFrequencyInfo> TempBFI;
938 BlockFrequencyInfo *CurrentCallerBFI = nullptr;
940 auto ComputeCurrBFI = [&,this](Function *Caller) {
941 // For the old pass manager:
943 DominatorTree DT(*Caller);
945 BranchProbabilityInfo BPI(*Caller, LI);
946 TempBFI.reset(new BlockFrequencyInfo(*Caller, BPI, LI));
947 CurrentCallerBFI = TempBFI.get();
950 CurrentCallerBFI = &(*GetBFI)(*Caller);
954 for (User *User : Users) {
955 CallSite CS = getCallSite(User);
956 Function *Caller = CS.getCaller();
957 if (CurrentCaller != Caller) {
958 CurrentCaller = Caller;
959 ComputeCurrBFI(Caller);
961 assert(CurrentCallerBFI && "CallerBFI is not set");
963 BasicBlock *CallBB = CS.getInstruction()->getParent();
964 auto Count = CurrentCallerBFI->getBlockProfileCount(CallBB);
966 CallSiteToProfCountMap[User] = *Count;
968 CallSiteToProfCountMap[User] = 0;
972 PartialInlinerImpl::FunctionCloner::FunctionCloner(
973 Function *F, FunctionOutliningInfo *OI, OptimizationRemarkEmitter &ORE)
974 : OrigFunc(F), ORE(ORE) {
975 ClonedOI = llvm::make_unique<FunctionOutliningInfo>();
977 // Clone the function, so that we can hack away on it.
978 ValueToValueMapTy VMap;
979 ClonedFunc = CloneFunction(F, VMap);
981 ClonedOI->ReturnBlock = cast<BasicBlock>(VMap[OI->ReturnBlock]);
982 ClonedOI->NonReturnBlock = cast<BasicBlock>(VMap[OI->NonReturnBlock]);
983 for (BasicBlock *BB : OI->Entries) {
984 ClonedOI->Entries.push_back(cast<BasicBlock>(VMap[BB]));
986 for (BasicBlock *E : OI->ReturnBlockPreds) {
987 BasicBlock *NewE = cast<BasicBlock>(VMap[E]);
988 ClonedOI->ReturnBlockPreds.push_back(NewE);
990 // Go ahead and update all uses to the duplicate, so that we can just
991 // use the inliner functionality when we're done hacking.
992 F->replaceAllUsesWith(ClonedFunc);
995 PartialInlinerImpl::FunctionCloner::FunctionCloner(
996 Function *F, FunctionOutliningMultiRegionInfo *OI,
997 OptimizationRemarkEmitter &ORE)
998 : OrigFunc(F), ORE(ORE) {
999 ClonedOMRI = llvm::make_unique<FunctionOutliningMultiRegionInfo>();
1001 // Clone the function, so that we can hack away on it.
1002 ValueToValueMapTy VMap;
1003 ClonedFunc = CloneFunction(F, VMap);
1005 // Go through all Outline Candidate Regions and update all BasicBlock
1007 for (FunctionOutliningMultiRegionInfo::OutlineRegionInfo RegionInfo :
1009 SmallVector<BasicBlock *, 8> Region;
1010 for (BasicBlock *BB : RegionInfo.Region) {
1011 Region.push_back(cast<BasicBlock>(VMap[BB]));
1013 BasicBlock *NewEntryBlock = cast<BasicBlock>(VMap[RegionInfo.EntryBlock]);
1014 BasicBlock *NewExitBlock = cast<BasicBlock>(VMap[RegionInfo.ExitBlock]);
1015 BasicBlock *NewReturnBlock = nullptr;
1016 if (RegionInfo.ReturnBlock)
1017 NewReturnBlock = cast<BasicBlock>(VMap[RegionInfo.ReturnBlock]);
1018 FunctionOutliningMultiRegionInfo::OutlineRegionInfo MappedRegionInfo(
1019 Region, NewEntryBlock, NewExitBlock, NewReturnBlock);
1020 ClonedOMRI->ORI.push_back(MappedRegionInfo);
1022 // Go ahead and update all uses to the duplicate, so that we can just
1023 // use the inliner functionality when we're done hacking.
1024 F->replaceAllUsesWith(ClonedFunc);
1027 void PartialInlinerImpl::FunctionCloner::NormalizeReturnBlock() {
1028 auto getFirstPHI = [](BasicBlock *BB) {
1029 BasicBlock::iterator I = BB->begin();
1030 PHINode *FirstPhi = nullptr;
1031 while (I != BB->end()) {
1032 PHINode *Phi = dyn_cast<PHINode>(I);
1043 // Shouldn't need to normalize PHIs if we're not outlining non-early return
1048 // Special hackery is needed with PHI nodes that have inputs from more than
1049 // one extracted block. For simplicity, just split the PHIs into a two-level
1050 // sequence of PHIs, some of which will go in the extracted region, and some
1051 // of which will go outside.
1052 BasicBlock *PreReturn = ClonedOI->ReturnBlock;
1053 // only split block when necessary:
1054 PHINode *FirstPhi = getFirstPHI(PreReturn);
1055 unsigned NumPredsFromEntries = ClonedOI->ReturnBlockPreds.size();
1057 if (!FirstPhi || FirstPhi->getNumIncomingValues() <= NumPredsFromEntries + 1)
1060 auto IsTrivialPhi = [](PHINode *PN) -> Value * {
1061 Value *CommonValue = PN->getIncomingValue(0);
1062 if (all_of(PN->incoming_values(),
1063 [&](Value *V) { return V == CommonValue; }))
1068 ClonedOI->ReturnBlock = ClonedOI->ReturnBlock->splitBasicBlock(
1069 ClonedOI->ReturnBlock->getFirstNonPHI()->getIterator());
1070 BasicBlock::iterator I = PreReturn->begin();
1071 Instruction *Ins = &ClonedOI->ReturnBlock->front();
1072 SmallVector<Instruction *, 4> DeadPhis;
1073 while (I != PreReturn->end()) {
1074 PHINode *OldPhi = dyn_cast<PHINode>(I);
1079 PHINode::Create(OldPhi->getType(), NumPredsFromEntries + 1, "", Ins);
1080 OldPhi->replaceAllUsesWith(RetPhi);
1081 Ins = ClonedOI->ReturnBlock->getFirstNonPHI();
1083 RetPhi->addIncoming(&*I, PreReturn);
1084 for (BasicBlock *E : ClonedOI->ReturnBlockPreds) {
1085 RetPhi->addIncoming(OldPhi->getIncomingValueForBlock(E), E);
1086 OldPhi->removeIncomingValue(E);
1089 // After incoming values splitting, the old phi may become trivial.
1090 // Keeping the trivial phi can introduce definition inside the outline
1091 // region which is live-out, causing necessary overhead (load, store
1092 // arg passing etc).
1093 if (auto *OldPhiVal = IsTrivialPhi(OldPhi)) {
1094 OldPhi->replaceAllUsesWith(OldPhiVal);
1095 DeadPhis.push_back(OldPhi);
1099 for (auto *DP : DeadPhis)
1100 DP->eraseFromParent();
1102 for (auto E : ClonedOI->ReturnBlockPreds) {
1103 E->getTerminator()->replaceUsesOfWith(PreReturn, ClonedOI->ReturnBlock);
1107 bool PartialInlinerImpl::FunctionCloner::doMultiRegionFunctionOutlining() {
1109 auto ComputeRegionCost = [](SmallVectorImpl<BasicBlock *> &Region) {
1111 for (BasicBlock* BB : Region)
1112 Cost += computeBBInlineCost(BB);
1116 assert(ClonedOMRI && "Expecting OutlineInfo for multi region outline");
1118 if (ClonedOMRI->ORI.empty())
1121 // The CodeExtractor needs a dominator tree.
1123 DT.recalculate(*ClonedFunc);
1125 // Manually calculate a BlockFrequencyInfo and BranchProbabilityInfo.
1127 BranchProbabilityInfo BPI(*ClonedFunc, LI);
1128 ClonedFuncBFI.reset(new BlockFrequencyInfo(*ClonedFunc, BPI, LI));
1130 SetVector<Value *> Inputs, Outputs, Sinks;
1131 for (FunctionOutliningMultiRegionInfo::OutlineRegionInfo RegionInfo :
1133 int CurrentOutlinedRegionCost = ComputeRegionCost(RegionInfo.Region);
1135 CodeExtractor CE(RegionInfo.Region, &DT, /*AggregateArgs*/ false,
1136 ClonedFuncBFI.get(), &BPI, /* AllowVarargs */ false);
1138 CE.findInputsOutputs(Inputs, Outputs, Sinks);
1141 if (TracePartialInlining) {
1142 dbgs() << "inputs: " << Inputs.size() << "\n";
1143 dbgs() << "outputs: " << Outputs.size() << "\n";
1144 for (Value *value : Inputs)
1145 dbgs() << "value used in func: " << *value << "\n";
1146 for (Value *output : Outputs)
1147 dbgs() << "instr used in func: " << *output << "\n";
1150 // Do not extract regions that have live exit variables.
1151 if (Outputs.size() > 0 && !ForceLiveExit)
1154 Function *OutlinedFunc = CE.extractCodeRegion();
1157 CallSite OCS = PartialInlinerImpl::getOneCallSiteTo(OutlinedFunc);
1158 BasicBlock *OutliningCallBB = OCS.getInstruction()->getParent();
1159 assert(OutliningCallBB->getParent() == ClonedFunc);
1160 OutlinedFunctions.push_back(std::make_pair(OutlinedFunc,OutliningCallBB));
1161 NumColdRegionsOutlined++;
1162 OutlinedRegionCost += CurrentOutlinedRegionCost;
1164 if (MarkOutlinedColdCC) {
1165 OutlinedFunc->setCallingConv(CallingConv::Cold);
1166 OCS.setCallingConv(CallingConv::Cold);
1170 return OptimizationRemarkMissed(DEBUG_TYPE, "ExtractFailed",
1171 &RegionInfo.Region.front()->front())
1172 << "Failed to extract region at block "
1173 << ore::NV("Block", RegionInfo.Region.front());
1177 return !OutlinedFunctions.empty();
1181 PartialInlinerImpl::FunctionCloner::doSingleRegionFunctionOutlining() {
1182 // Returns true if the block is to be partial inlined into the caller
1183 // (i.e. not to be extracted to the out of line function)
1184 auto ToBeInlined = [&, this](BasicBlock *BB) {
1185 return BB == ClonedOI->ReturnBlock ||
1186 (std::find(ClonedOI->Entries.begin(), ClonedOI->Entries.end(), BB) !=
1187 ClonedOI->Entries.end());
1190 assert(ClonedOI && "Expecting OutlineInfo for single region outline");
1191 // The CodeExtractor needs a dominator tree.
1193 DT.recalculate(*ClonedFunc);
1195 // Manually calculate a BlockFrequencyInfo and BranchProbabilityInfo.
1197 BranchProbabilityInfo BPI(*ClonedFunc, LI);
1198 ClonedFuncBFI.reset(new BlockFrequencyInfo(*ClonedFunc, BPI, LI));
1200 // Gather up the blocks that we're going to extract.
1201 std::vector<BasicBlock *> ToExtract;
1202 ToExtract.push_back(ClonedOI->NonReturnBlock);
1203 OutlinedRegionCost +=
1204 PartialInlinerImpl::computeBBInlineCost(ClonedOI->NonReturnBlock);
1205 for (BasicBlock &BB : *ClonedFunc)
1206 if (!ToBeInlined(&BB) && &BB != ClonedOI->NonReturnBlock) {
1207 ToExtract.push_back(&BB);
1208 // FIXME: the code extractor may hoist/sink more code
1209 // into the outlined function which may make the outlining
1210 // overhead (the difference of the outlined function cost
1211 // and OutliningRegionCost) look larger.
1212 OutlinedRegionCost += computeBBInlineCost(&BB);
1215 // Extract the body of the if.
1216 Function *OutlinedFunc =
1217 CodeExtractor(ToExtract, &DT, /*AggregateArgs*/ false,
1218 ClonedFuncBFI.get(), &BPI,
1219 /* AllowVarargs */ true)
1220 .extractCodeRegion();
1223 BasicBlock *OutliningCallBB =
1224 PartialInlinerImpl::getOneCallSiteTo(OutlinedFunc)
1227 assert(OutliningCallBB->getParent() == ClonedFunc);
1228 OutlinedFunctions.push_back(std::make_pair(OutlinedFunc, OutliningCallBB));
1231 return OptimizationRemarkMissed(DEBUG_TYPE, "ExtractFailed",
1232 &ToExtract.front()->front())
1233 << "Failed to extract region at block "
1234 << ore::NV("Block", ToExtract.front());
1237 return OutlinedFunc;
1240 PartialInlinerImpl::FunctionCloner::~FunctionCloner() {
1241 // Ditch the duplicate, since we're done with it, and rewrite all remaining
1242 // users (function pointers, etc.) back to the original function.
1243 ClonedFunc->replaceAllUsesWith(OrigFunc);
1244 ClonedFunc->eraseFromParent();
1245 if (!IsFunctionInlined) {
1246 // Remove each function that was speculatively created if there is no
1248 for (auto FuncBBPair : OutlinedFunctions) {
1249 Function *Func = FuncBBPair.first;
1250 Func->eraseFromParent();
1255 std::pair<bool, Function *> PartialInlinerImpl::unswitchFunction(Function *F) {
1257 if (F->hasAddressTaken())
1258 return {false, nullptr};
1260 // Let inliner handle it
1261 if (F->hasFnAttribute(Attribute::AlwaysInline))
1262 return {false, nullptr};
1264 if (F->hasFnAttribute(Attribute::NoInline))
1265 return {false, nullptr};
1267 if (PSI->isFunctionEntryCold(F))
1268 return {false, nullptr};
1270 if (F->user_begin() == F->user_end())
1271 return {false, nullptr};
1273 auto &ORE = (*GetORE)(*F);
1275 // Only try to outline cold regions if we have a profile summary, which
1276 // implies we have profiling information.
1277 if (PSI->hasProfileSummary() && F->hasProfileData() &&
1278 !DisableMultiRegionPartialInline) {
1279 std::unique_ptr<FunctionOutliningMultiRegionInfo> OMRI =
1280 computeOutliningColdRegionsInfo(F);
1282 FunctionCloner Cloner(F, OMRI.get(), ORE);
1285 if (TracePartialInlining) {
1286 dbgs() << "HotCountThreshold = " << PSI->getHotCountThreshold() << "\n";
1287 dbgs() << "ColdCountThreshold = " << PSI->getColdCountThreshold()
1291 bool DidOutline = Cloner.doMultiRegionFunctionOutlining();
1295 if (TracePartialInlining) {
1296 dbgs() << ">>>>>> Outlined (Cloned) Function >>>>>>\n";
1297 Cloner.ClonedFunc->print(dbgs());
1298 dbgs() << "<<<<<< Outlined (Cloned) Function <<<<<<\n";
1302 if (tryPartialInline(Cloner))
1303 return {true, nullptr};
1308 // Fall-thru to regular partial inlining if we:
1309 // i) can't find any cold regions to outline, or
1310 // ii) can't inline the outlined function anywhere.
1311 std::unique_ptr<FunctionOutliningInfo> OI = computeOutliningInfo(F);
1313 return {false, nullptr};
1315 FunctionCloner Cloner(F, OI.get(), ORE);
1316 Cloner.NormalizeReturnBlock();
1318 Function *OutlinedFunction = Cloner.doSingleRegionFunctionOutlining();
1320 if (!OutlinedFunction)
1321 return {false, nullptr};
1323 bool AnyInline = tryPartialInline(Cloner);
1326 return {true, OutlinedFunction};
1328 return {false, nullptr};
1331 bool PartialInlinerImpl::tryPartialInline(FunctionCloner &Cloner) {
1332 if (Cloner.OutlinedFunctions.empty())
1336 BlockFrequency WeightedRcost;
1337 int NonWeightedRcost;
1338 std::tie(SizeCost, NonWeightedRcost) = computeOutliningCosts(Cloner);
1340 // Only calculate RelativeToEntryFreq when we are doing single region
1342 BranchProbability RelativeToEntryFreq;
1343 if (Cloner.ClonedOI) {
1344 RelativeToEntryFreq = getOutliningCallBBRelativeFreq(Cloner);
1346 // RelativeToEntryFreq doesn't make sense when we have more than one
1347 // outlined call because each call will have a different relative frequency
1348 // to the entry block. We can consider using the average, but the
1349 // usefulness of that information is questionable. For now, assume we never
1350 // execute the calls to outlined functions.
1351 RelativeToEntryFreq = BranchProbability(0, 1);
1353 WeightedRcost = BlockFrequency(NonWeightedRcost) * RelativeToEntryFreq;
1355 // The call sequence(s) to the outlined function(s) are larger than the sum of
1356 // the original outlined region size(s), it does not increase the chances of
1357 // inlining the function with outlining (The inliner uses the size increase to
1358 // model the cost of inlining a callee).
1359 if (!SkipCostAnalysis && Cloner.OutlinedRegionCost < SizeCost) {
1360 auto &ORE = (*GetORE)(*Cloner.OrigFunc);
1363 std::tie(DLoc, Block) = getOneDebugLoc(Cloner.ClonedFunc);
1365 return OptimizationRemarkAnalysis(DEBUG_TYPE, "OutlineRegionTooSmall",
1367 << ore::NV("Function", Cloner.OrigFunc)
1368 << " not partially inlined into callers (Original Size = "
1369 << ore::NV("OutlinedRegionOriginalSize", Cloner.OutlinedRegionCost)
1370 << ", Size of call sequence to outlined function = "
1371 << ore::NV("NewSize", SizeCost) << ")";
1376 assert(Cloner.OrigFunc->user_begin() == Cloner.OrigFunc->user_end() &&
1377 "F's users should all be replaced!");
1379 std::vector<User *> Users(Cloner.ClonedFunc->user_begin(),
1380 Cloner.ClonedFunc->user_end());
1382 DenseMap<User *, uint64_t> CallSiteToProfCountMap;
1383 auto CalleeEntryCount = Cloner.OrigFunc->getEntryCount();
1384 if (CalleeEntryCount)
1385 computeCallsiteToProfCountMap(Cloner.ClonedFunc, CallSiteToProfCountMap);
1387 uint64_t CalleeEntryCountV = (CalleeEntryCount ? *CalleeEntryCount : 0);
1389 bool AnyInline = false;
1390 for (User *User : Users) {
1391 CallSite CS = getCallSite(User);
1393 if (IsLimitReached())
1397 if (!shouldPartialInline(CS, Cloner, WeightedRcost))
1400 auto &ORE = (*GetORE)(*CS.getCaller());
1401 // Construct remark before doing the inlining, as after successful inlining
1402 // the callsite is removed.
1403 OptimizationRemark OR(DEBUG_TYPE, "PartiallyInlined", CS.getInstruction());
1404 OR << ore::NV("Callee", Cloner.OrigFunc) << " partially inlined into "
1405 << ore::NV("Caller", CS.getCaller());
1407 InlineFunctionInfo IFI(nullptr, GetAssumptionCache, PSI);
1408 // We can only forward varargs when we outlined a single region, else we
1409 // bail on vararg functions.
1410 if (!InlineFunction(CS, IFI, nullptr, true,
1411 (Cloner.ClonedOI ? Cloner.OutlinedFunctions.back().first
1417 // Now update the entry count:
1418 if (CalleeEntryCountV && CallSiteToProfCountMap.count(User)) {
1419 uint64_t CallSiteCount = CallSiteToProfCountMap[User];
1420 CalleeEntryCountV -= std::min(CalleeEntryCountV, CallSiteCount);
1424 NumPartialInlining++;
1426 if (Cloner.ClonedOI)
1427 NumPartialInlined++;
1429 NumColdOutlinePartialInlined++;
1434 Cloner.IsFunctionInlined = true;
1435 if (CalleeEntryCount)
1436 Cloner.OrigFunc->setEntryCount(CalleeEntryCountV);
1437 auto &ORE = (*GetORE)(*Cloner.OrigFunc);
1439 return OptimizationRemark(DEBUG_TYPE, "PartiallyInlined", Cloner.OrigFunc)
1440 << "Partially inlined into at least one caller";
1448 bool PartialInlinerImpl::run(Module &M) {
1449 if (DisablePartialInlining)
1452 std::vector<Function *> Worklist;
1453 Worklist.reserve(M.size());
1454 for (Function &F : M)
1455 if (!F.use_empty() && !F.isDeclaration())
1456 Worklist.push_back(&F);
1458 bool Changed = false;
1459 while (!Worklist.empty()) {
1460 Function *CurrFunc = Worklist.back();
1461 Worklist.pop_back();
1463 if (CurrFunc->use_empty())
1466 bool Recursive = false;
1467 for (User *U : CurrFunc->users())
1468 if (Instruction *I = dyn_cast<Instruction>(U))
1469 if (I->getParent()->getParent() == CurrFunc) {
1476 std::pair<bool, Function * > Result = unswitchFunction(CurrFunc);
1478 Worklist.push_back(Result.second);
1487 char PartialInlinerLegacyPass::ID = 0;
1489 INITIALIZE_PASS_BEGIN(PartialInlinerLegacyPass, "partial-inliner",
1490 "Partial Inliner", false, false)
1491 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
1492 INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
1493 INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
1494 INITIALIZE_PASS_END(PartialInlinerLegacyPass, "partial-inliner",
1495 "Partial Inliner", false, false)
1497 ModulePass *llvm::createPartialInliningPass() {
1498 return new PartialInlinerLegacyPass();
1501 PreservedAnalyses PartialInlinerPass::run(Module &M,
1502 ModuleAnalysisManager &AM) {
1503 auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
1505 std::function<AssumptionCache &(Function &)> GetAssumptionCache =
1506 [&FAM](Function &F) -> AssumptionCache & {
1507 return FAM.getResult<AssumptionAnalysis>(F);
1510 std::function<BlockFrequencyInfo &(Function &)> GetBFI =
1511 [&FAM](Function &F) -> BlockFrequencyInfo & {
1512 return FAM.getResult<BlockFrequencyAnalysis>(F);
1515 std::function<TargetTransformInfo &(Function &)> GetTTI =
1516 [&FAM](Function &F) -> TargetTransformInfo & {
1517 return FAM.getResult<TargetIRAnalysis>(F);
1520 std::function<OptimizationRemarkEmitter &(Function &)> GetORE =
1521 [&FAM](Function &F) -> OptimizationRemarkEmitter & {
1522 return FAM.getResult<OptimizationRemarkEmitterAnalysis>(F);
1525 ProfileSummaryInfo *PSI = &AM.getResult<ProfileSummaryAnalysis>(M);
1527 if (PartialInlinerImpl(&GetAssumptionCache, &GetTTI, {GetBFI}, PSI, &GetORE)
1529 return PreservedAnalyses::none();
1530 return PreservedAnalyses::all();