1//===- InlineCost.cpp - Cost analysis for inliner -------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements inline cost analysis.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Analysis/InlineCost.h"
14#include "llvm/ADT/STLExtras.h"
15#include "llvm/ADT/SetVector.h"
16#include "llvm/ADT/SmallPtrSet.h"
17#include "llvm/ADT/SmallVector.h"
18#include "llvm/ADT/Statistic.h"
19#include "llvm/Analysis/AssumptionCache.h"
20#include "llvm/Analysis/BlockFrequencyInfo.h"
21#include "llvm/Analysis/CodeMetrics.h"
22#include "llvm/Analysis/ConstantFolding.h"
23#include "llvm/Analysis/InstructionSimplify.h"
24#include "llvm/Analysis/LoopInfo.h"
25#include "llvm/Analysis/MemoryBuiltins.h"
26#include "llvm/Analysis/OptimizationRemarkEmitter.h"
27#include "llvm/Analysis/ProfileSummaryInfo.h"
28#include "llvm/Analysis/TargetLibraryInfo.h"
29#include "llvm/Analysis/TargetTransformInfo.h"
30#include "llvm/Analysis/ValueTracking.h"
31#include "llvm/Config/llvm-config.h"
32#include "llvm/IR/AssemblyAnnotationWriter.h"
33#include "llvm/IR/CallingConv.h"
34#include "llvm/IR/DataLayout.h"
35#include "llvm/IR/Dominators.h"
36#include "llvm/IR/GetElementPtrTypeIterator.h"
37#include "llvm/IR/GlobalAlias.h"
38#include "llvm/IR/InstVisitor.h"
39#include "llvm/IR/IntrinsicInst.h"
40#include "llvm/IR/Operator.h"
41#include "llvm/IR/PatternMatch.h"
42#include "llvm/Support/CommandLine.h"
43#include "llvm/Support/Debug.h"
44#include "llvm/Support/FormattedStream.h"
45#include "llvm/Support/raw_ostream.h"
46#include <climits>
47#include <limits>
48#include <optional>
49
50using namespace llvm;
51
52#define DEBUG_TYPE "inline-cost"
53
54STATISTIC(NumCallsAnalyzed, "Number of call sites analyzed");
55
56static cl::opt<int>
57 DefaultThreshold("inlinedefault-threshold", cl::Hidden, cl::init(Val: 225),
58 cl::desc("Default amount of inlining to perform"));
59
60// We introduce this option since there is a minor compile-time win by avoiding
61// addition of TTI attributes (target-features in particular) to inline
62// candidates when they are guaranteed to be the same as top level methods in
63// some use cases. If we avoid adding the attribute, we need an option to avoid
64// checking these attributes.
65static cl::opt<bool> IgnoreTTIInlineCompatible(
66 "ignore-tti-inline-compatible", cl::Hidden, cl::init(Val: false),
67 cl::desc("Ignore TTI attributes compatibility check between callee/caller "
68 "during inline cost calculation"));
69
70static cl::opt<bool> PrintInstructionComments(
71 "print-instruction-comments", cl::Hidden, cl::init(Val: false),
72 cl::desc("Prints comments for instruction based on inline cost analysis"));
73
74static cl::opt<int> InlineThreshold(
75 "inline-threshold", cl::Hidden, cl::init(Val: 225),
76 cl::desc("Control the amount of inlining to perform (default = 225)"));
77
78static cl::opt<int> HintThreshold(
79 "inlinehint-threshold", cl::Hidden, cl::init(Val: 325),
80 cl::desc("Threshold for inlining functions with inline hint"));
81
82static cl::opt<int>
83 ColdCallSiteThreshold("inline-cold-callsite-threshold", cl::Hidden,
84 cl::init(Val: 45),
85 cl::desc("Threshold for inlining cold callsites"));
86
87static cl::opt<bool> InlineEnableCostBenefitAnalysis(
88 "inline-enable-cost-benefit-analysis", cl::Hidden, cl::init(Val: false),
89 cl::desc("Enable the cost-benefit analysis for the inliner"));
90
91// InlineSavingsMultiplier overrides per TTI multipliers iff it is
92// specified explicitly in command line options. This option is exposed
93// for tuning and testing.
94static cl::opt<int> InlineSavingsMultiplier(
95 "inline-savings-multiplier", cl::Hidden, cl::init(Val: 8),
96 cl::desc("Multiplier to multiply cycle savings by during inlining"));
97
98// InlineSavingsProfitableMultiplier overrides per TTI multipliers iff it is
99// specified explicitly in command line options. This option is exposed
100// for tuning and testing.
101static cl::opt<int> InlineSavingsProfitableMultiplier(
102 "inline-savings-profitable-multiplier", cl::Hidden, cl::init(Val: 4),
103 cl::desc("A multiplier on top of cycle savings to decide whether the "
104 "savings won't justify the cost"));
105
106static cl::opt<int>
107 InlineSizeAllowance("inline-size-allowance", cl::Hidden, cl::init(Val: 100),
108 cl::desc("The maximum size of a callee that get's "
109 "inlined without sufficient cycle savings"));
110
111// We introduce this threshold to help performance of instrumentation based
112// PGO before we actually hook up inliner with analysis passes such as BPI and
113// BFI.
114static cl::opt<int> ColdThreshold(
115 "inlinecold-threshold", cl::Hidden, cl::init(Val: 45),
116 cl::desc("Threshold for inlining functions with cold attribute"));
117
118static cl::opt<int>
119 HotCallSiteThreshold("hot-callsite-threshold", cl::Hidden, cl::init(Val: 3000),
120 cl::desc("Threshold for hot callsites "));
121
122static cl::opt<int> LocallyHotCallSiteThreshold(
123 "locally-hot-callsite-threshold", cl::Hidden, cl::init(Val: 525),
124 cl::desc("Threshold for locally hot callsites "));
125
126static cl::opt<int> ColdCallSiteRelFreq(
127 "cold-callsite-rel-freq", cl::Hidden, cl::init(Val: 2),
128 cl::desc("Maximum block frequency, expressed as a percentage of caller's "
129 "entry frequency, for a callsite to be cold in the absence of "
130 "profile information."));
131
132static cl::opt<uint64_t> HotCallSiteRelFreq(
133 "hot-callsite-rel-freq", cl::Hidden, cl::init(Val: 60),
134 cl::desc("Minimum block frequency, expressed as a multiple of caller's "
135 "entry frequency, for a callsite to be hot in the absence of "
136 "profile information."));
137
138static cl::opt<int>
139 InstrCost("inline-instr-cost", cl::Hidden, cl::init(Val: 5),
140 cl::desc("Cost of a single instruction when inlining"));
141
142static cl::opt<int>
143 MemAccessCost("inline-memaccess-cost", cl::Hidden, cl::init(Val: 0),
144 cl::desc("Cost of load/store instruction when inlining"));
145
146static cl::opt<int> CallPenalty(
147 "inline-call-penalty", cl::Hidden, cl::init(Val: 25),
148 cl::desc("Call penalty that is applied per callsite when inlining"));
149
150static cl::opt<size_t>
151 StackSizeThreshold("inline-max-stacksize", cl::Hidden,
152 cl::init(Val: std::numeric_limits<size_t>::max()),
153 cl::desc("Do not inline functions with a stack size "
154 "that exceeds the specified limit"));
155
156static cl::opt<size_t> RecurStackSizeThreshold(
157 "recursive-inline-max-stacksize", cl::Hidden,
158 cl::init(Val: InlineConstants::TotalAllocaSizeRecursiveCaller),
159 cl::desc("Do not inline recursive functions with a stack "
160 "size that exceeds the specified limit"));
161
162static cl::opt<bool> OptComputeFullInlineCost(
163 "inline-cost-full", cl::Hidden,
164 cl::desc("Compute the full inline cost of a call site even when the cost "
165 "exceeds the threshold."));
166
167static cl::opt<bool> InlineCallerSupersetNoBuiltin(
168 "inline-caller-superset-nobuiltin", cl::Hidden, cl::init(Val: true),
169 cl::desc("Allow inlining when caller has a superset of callee's nobuiltin "
170 "attributes."));
171
172static cl::opt<bool> DisableGEPConstOperand(
173 "disable-gep-const-evaluation", cl::Hidden, cl::init(Val: false),
174 cl::desc("Disables evaluation of GetElementPtr with constant operands"));
175
176namespace llvm {
177std::optional<int> getStringFnAttrAsInt(const Attribute &Attr) {
178 if (Attr.isValid()) {
179 int AttrValue = 0;
180 if (!Attr.getValueAsString().getAsInteger(Radix: 10, Result&: AttrValue))
181 return AttrValue;
182 }
183 return std::nullopt;
184}
185
186std::optional<int> getStringFnAttrAsInt(CallBase &CB, StringRef AttrKind) {
187 return getStringFnAttrAsInt(Attr: CB.getFnAttr(Kind: AttrKind));
188}
189
190std::optional<int> getStringFnAttrAsInt(Function *F, StringRef AttrKind) {
191 return getStringFnAttrAsInt(Attr: F->getFnAttribute(Kind: AttrKind));
192}
193
194namespace InlineConstants {
195int getInstrCost() { return InstrCost; }
196
197} // namespace InlineConstants
198
199} // namespace llvm
200
201namespace {
202class InlineCostCallAnalyzer;
203
204// This struct is used to store information about inline cost of a
205// particular instruction
206struct InstructionCostDetail {
207 int CostBefore = 0;
208 int CostAfter = 0;
209 int ThresholdBefore = 0;
210 int ThresholdAfter = 0;
211
212 int getThresholdDelta() const { return ThresholdAfter - ThresholdBefore; }
213
214 int getCostDelta() const { return CostAfter - CostBefore; }
215
216 bool hasThresholdChanged() const { return ThresholdAfter != ThresholdBefore; }
217};
218
219class InlineCostAnnotationWriter : public AssemblyAnnotationWriter {
220private:
221 InlineCostCallAnalyzer *const ICCA;
222
223public:
224 InlineCostAnnotationWriter(InlineCostCallAnalyzer *ICCA) : ICCA(ICCA) {}
225 void emitInstructionAnnot(const Instruction *I,
226 formatted_raw_ostream &OS) override;
227};
228
229/// Carry out call site analysis, in order to evaluate inlinability.
230/// NOTE: the type is currently used as implementation detail of functions such
231/// as llvm::getInlineCost. Note the function_ref constructor parameters - the
232/// expectation is that they come from the outer scope, from the wrapper
233/// functions. If we want to support constructing CallAnalyzer objects where
234/// lambdas are provided inline at construction, or where the object needs to
235/// otherwise survive past the scope of the provided functions, we need to
236/// revisit the argument types.
237class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
238 typedef InstVisitor<CallAnalyzer, bool> Base;
239 friend class InstVisitor<CallAnalyzer, bool>;
240
241protected:
242 virtual ~CallAnalyzer() = default;
243 /// The TargetTransformInfo available for this compilation.
244 const TargetTransformInfo &TTI;
245
246 /// Getter for the cache of @llvm.assume intrinsics.
247 function_ref<AssumptionCache &(Function &)> GetAssumptionCache;
248
249 /// Getter for BlockFrequencyInfo
250 function_ref<BlockFrequencyInfo &(Function &)> GetBFI;
251
252 /// Profile summary information.
253 ProfileSummaryInfo *PSI;
254
255 /// The called function.
256 Function &F;
257
258 // Cache the DataLayout since we use it a lot.
259 const DataLayout &DL;
260
261 /// The OptimizationRemarkEmitter available for this compilation.
262 OptimizationRemarkEmitter *ORE;
263
264 /// The candidate callsite being analyzed. Please do not use this to do
265 /// analysis in the caller function; we want the inline cost query to be
266 /// easily cacheable. Instead, use the cover function paramHasAttr.
267 CallBase &CandidateCall;
268
269 /// Extension points for handling callsite features.
270 // Called before a basic block was analyzed.
271 virtual void onBlockStart(const BasicBlock *BB) {}
272
273 /// Called after a basic block was analyzed.
274 virtual void onBlockAnalyzed(const BasicBlock *BB) {}
275
276 /// Called before an instruction was analyzed
277 virtual void onInstructionAnalysisStart(const Instruction *I) {}
278
279 /// Called after an instruction was analyzed
280 virtual void onInstructionAnalysisFinish(const Instruction *I) {}
281
282 /// Called at the end of the analysis of the callsite. Return the outcome of
283 /// the analysis, i.e. 'InlineResult(true)' if the inlining may happen, or
284 /// the reason it can't.
285 virtual InlineResult finalizeAnalysis() { return InlineResult::success(); }
286 /// Called when we're about to start processing a basic block, and every time
287 /// we are done processing an instruction. Return true if there is no point in
288 /// continuing the analysis (e.g. we've determined already the call site is
289 /// too expensive to inline)
290 virtual bool shouldStop() { return false; }
291
292 /// Called before the analysis of the callee body starts (with callsite
293 /// contexts propagated). It checks callsite-specific information. Return a
294 /// reason analysis can't continue if that's the case, or 'true' if it may
295 /// continue.
296 virtual InlineResult onAnalysisStart() { return InlineResult::success(); }
297 /// Called if the analysis engine decides SROA cannot be done for the given
298 /// alloca.
299 virtual void onDisableSROA(AllocaInst *Arg) {}
300
301 /// Called the analysis engine determines load elimination won't happen.
302 virtual void onDisableLoadElimination() {}
303
304 /// Called when we visit a CallBase, before the analysis starts. Return false
305 /// to stop further processing of the instruction.
306 virtual bool onCallBaseVisitStart(CallBase &Call) { return true; }
307
308 /// Called to account for a call.
309 virtual void onCallPenalty() {}
310
311 /// Called to account for a load or store.
312 virtual void onMemAccess(){};
313
314 /// Called to account for the expectation the inlining would result in a load
315 /// elimination.
316 virtual void onLoadEliminationOpportunity() {}
317
318 /// Called to account for the cost of argument setup for the Call in the
319 /// callee's body (not the callsite currently under analysis).
320 virtual void onCallArgumentSetup(const CallBase &Call) {}
321
322 /// Called to account for a load relative intrinsic.
323 virtual void onLoadRelativeIntrinsic() {}
324
325 /// Called to account for a lowered call.
326 virtual void onLoweredCall(Function *F, CallBase &Call, bool IsIndirectCall) {
327 }
328
329 /// Account for a jump table of given size. Return false to stop further
330 /// processing the switch instruction
331 virtual bool onJumpTable(unsigned JumpTableSize) { return true; }
332
333 /// Account for a case cluster of given size. Return false to stop further
334 /// processing of the instruction.
335 virtual bool onCaseCluster(unsigned NumCaseCluster) { return true; }
336
337 /// Called at the end of processing a switch instruction, with the given
338 /// number of case clusters.
339 virtual void onFinalizeSwitch(unsigned JumpTableSize, unsigned NumCaseCluster,
340 bool DefaultDestUndefined) {}
341
342 /// Called to account for any other instruction not specifically accounted
343 /// for.
344 virtual void onMissedSimplification() {}
345
346 /// Start accounting potential benefits due to SROA for the given alloca.
347 virtual void onInitializeSROAArg(AllocaInst *Arg) {}
348
349 /// Account SROA savings for the AllocaInst value.
350 virtual void onAggregateSROAUse(AllocaInst *V) {}
351
352 bool handleSROA(Value *V, bool DoNotDisable) {
353 // Check for SROA candidates in comparisons.
354 if (auto *SROAArg = getSROAArgForValueOrNull(V)) {
355 if (DoNotDisable) {
356 onAggregateSROAUse(V: SROAArg);
357 return true;
358 }
359 disableSROAForArg(SROAArg);
360 }
361 return false;
362 }
363
364 bool IsCallerRecursive = false;
365 bool IsRecursiveCall = false;
366 bool ExposesReturnsTwice = false;
367 bool HasDynamicAlloca = false;
368 bool ContainsNoDuplicateCall = false;
369 bool HasReturn = false;
370 bool HasIndirectBr = false;
371 bool HasUninlineableIntrinsic = false;
372 bool InitsVargArgs = false;
373
374 /// Number of bytes allocated statically by the callee.
375 uint64_t AllocatedSize = 0;
376 unsigned NumInstructions = 0;
377 unsigned NumVectorInstructions = 0;
378
379 /// While we walk the potentially-inlined instructions, we build up and
380 /// maintain a mapping of simplified values specific to this callsite. The
381 /// idea is to propagate any special information we have about arguments to
382 /// this call through the inlinable section of the function, and account for
383 /// likely simplifications post-inlining. The most important aspect we track
384 /// is CFG altering simplifications -- when we prove a basic block dead, that
385 /// can cause dramatic shifts in the cost of inlining a function.
386 DenseMap<Value *, Constant *> SimplifiedValues;
387
388 /// Keep track of the values which map back (through function arguments) to
389 /// allocas on the caller stack which could be simplified through SROA.
390 DenseMap<Value *, AllocaInst *> SROAArgValues;
391
392 /// Keep track of Allocas for which we believe we may get SROA optimization.
393 DenseSet<AllocaInst *> EnabledSROAAllocas;
394
395 /// Keep track of values which map to a pointer base and constant offset.
396 DenseMap<Value *, std::pair<Value *, APInt>> ConstantOffsetPtrs;
397
398 /// Keep track of dead blocks due to the constant arguments.
399 SmallPtrSet<BasicBlock *, 16> DeadBlocks;
400
401 /// The mapping of the blocks to their known unique successors due to the
402 /// constant arguments.
403 DenseMap<BasicBlock *, BasicBlock *> KnownSuccessors;
404
405 /// Model the elimination of repeated loads that is expected to happen
406 /// whenever we simplify away the stores that would otherwise cause them to be
407 /// loads.
408 bool EnableLoadElimination = true;
409
410 /// Whether we allow inlining for recursive call.
411 bool AllowRecursiveCall = false;
412
413 SmallPtrSet<Value *, 16> LoadAddrSet;
414
415 AllocaInst *getSROAArgForValueOrNull(Value *V) const {
416 auto It = SROAArgValues.find(Val: V);
417 if (It == SROAArgValues.end() || EnabledSROAAllocas.count(V: It->second) == 0)
418 return nullptr;
419 return It->second;
420 }
421
422 // Custom simplification helper routines.
423 bool isAllocaDerivedArg(Value *V);
424 void disableSROAForArg(AllocaInst *SROAArg);
425 void disableSROA(Value *V);
426 void findDeadBlocks(BasicBlock *CurrBB, BasicBlock *NextBB);
427 void disableLoadElimination();
428 bool isGEPFree(GetElementPtrInst &GEP);
429 bool canFoldInboundsGEP(GetElementPtrInst &I);
430 bool accumulateGEPOffset(GEPOperator &GEP, APInt &Offset);
431 bool simplifyCallSite(Function *F, CallBase &Call);
432 bool simplifyInstruction(Instruction &I);
433 bool simplifyIntrinsicCallIsConstant(CallBase &CB);
434 bool simplifyIntrinsicCallObjectSize(CallBase &CB);
435 ConstantInt *stripAndComputeInBoundsConstantOffsets(Value *&V);
436
437 /// Return true if the given argument to the function being considered for
438 /// inlining has the given attribute set either at the call site or the
439 /// function declaration. Primarily used to inspect call site specific
440 /// attributes since these can be more precise than the ones on the callee
441 /// itself.
442 bool paramHasAttr(Argument *A, Attribute::AttrKind Attr);
443
444 /// Return true if the given value is known non null within the callee if
445 /// inlined through this particular callsite.
446 bool isKnownNonNullInCallee(Value *V);
447
448 /// Return true if size growth is allowed when inlining the callee at \p Call.
449 bool allowSizeGrowth(CallBase &Call);
450
451 // Custom analysis routines.
452 InlineResult analyzeBlock(BasicBlock *BB,
453 SmallPtrSetImpl<const Value *> &EphValues);
454
455 // Disable several entry points to the visitor so we don't accidentally use
456 // them by declaring but not defining them here.
457 void visit(Module *);
458 void visit(Module &);
459 void visit(Function *);
460 void visit(Function &);
461 void visit(BasicBlock *);
462 void visit(BasicBlock &);
463
464 // Provide base case for our instruction visit.
465 bool visitInstruction(Instruction &I);
466
467 // Our visit overrides.
468 bool visitAlloca(AllocaInst &I);
469 bool visitPHI(PHINode &I);
470 bool visitGetElementPtr(GetElementPtrInst &I);
471 bool visitBitCast(BitCastInst &I);
472 bool visitPtrToInt(PtrToIntInst &I);
473 bool visitIntToPtr(IntToPtrInst &I);
474 bool visitCastInst(CastInst &I);
475 bool visitCmpInst(CmpInst &I);
476 bool visitSub(BinaryOperator &I);
477 bool visitBinaryOperator(BinaryOperator &I);
478 bool visitFNeg(UnaryOperator &I);
479 bool visitLoad(LoadInst &I);
480 bool visitStore(StoreInst &I);
481 bool visitExtractValue(ExtractValueInst &I);
482 bool visitInsertValue(InsertValueInst &I);
483 bool visitCallBase(CallBase &Call);
484 bool visitReturnInst(ReturnInst &RI);
485 bool visitBranchInst(BranchInst &BI);
486 bool visitSelectInst(SelectInst &SI);
487 bool visitSwitchInst(SwitchInst &SI);
488 bool visitIndirectBrInst(IndirectBrInst &IBI);
489 bool visitResumeInst(ResumeInst &RI);
490 bool visitCleanupReturnInst(CleanupReturnInst &RI);
491 bool visitCatchReturnInst(CatchReturnInst &RI);
492 bool visitUnreachableInst(UnreachableInst &I);
493
494public:
495 CallAnalyzer(Function &Callee, CallBase &Call, const TargetTransformInfo &TTI,
496 function_ref<AssumptionCache &(Function &)> GetAssumptionCache,
497 function_ref<BlockFrequencyInfo &(Function &)> GetBFI = nullptr,
498 ProfileSummaryInfo *PSI = nullptr,
499 OptimizationRemarkEmitter *ORE = nullptr)
500 : TTI(TTI), GetAssumptionCache(GetAssumptionCache), GetBFI(GetBFI),
501 PSI(PSI), F(Callee), DL(F.getDataLayout()), ORE(ORE),
502 CandidateCall(Call) {}
503
504 InlineResult analyze();
505
506 std::optional<Constant *> getSimplifiedValue(Instruction *I) {
507 if (SimplifiedValues.contains(Val: I))
508 return SimplifiedValues[I];
509 return std::nullopt;
510 }
511
512 // Keep a bunch of stats about the cost savings found so we can print them
513 // out when debugging.
514 unsigned NumConstantArgs = 0;
515 unsigned NumConstantOffsetPtrArgs = 0;
516 unsigned NumAllocaArgs = 0;
517 unsigned NumConstantPtrCmps = 0;
518 unsigned NumConstantPtrDiffs = 0;
519 unsigned NumInstructionsSimplified = 0;
520
521 void dump();
522};
523
524// Considering forming a binary search, we should find the number of nodes
525// which is same as the number of comparisons when lowered. For a given
526// number of clusters, n, we can define a recursive function, f(n), to find
527// the number of nodes in the tree. The recursion is :
528// f(n) = 1 + f(n/2) + f (n - n/2), when n > 3,
529// and f(n) = n, when n <= 3.
530// This will lead a binary tree where the leaf should be either f(2) or f(3)
531// when n > 3. So, the number of comparisons from leaves should be n, while
532// the number of non-leaf should be :
533// 2^(log2(n) - 1) - 1
534// = 2^log2(n) * 2^-1 - 1
535// = n / 2 - 1.
536// Considering comparisons from leaf and non-leaf nodes, we can estimate the
537// number of comparisons in a simple closed form :
538// n + n / 2 - 1 = n * 3 / 2 - 1
539int64_t getExpectedNumberOfCompare(int NumCaseCluster) {
540 return 3 * static_cast<int64_t>(NumCaseCluster) / 2 - 1;
541}
542
543/// FIXME: if it is necessary to derive from InlineCostCallAnalyzer, note
544/// the FIXME in onLoweredCall, when instantiating an InlineCostCallAnalyzer
545class InlineCostCallAnalyzer final : public CallAnalyzer {
546 const bool ComputeFullInlineCost;
547 int LoadEliminationCost = 0;
548 /// Bonus to be applied when percentage of vector instructions in callee is
549 /// high (see more details in updateThreshold).
550 int VectorBonus = 0;
551 /// Bonus to be applied when the callee has only one reachable basic block.
552 int SingleBBBonus = 0;
553
554 /// Tunable parameters that control the analysis.
555 const InlineParams &Params;
556
557 // This DenseMap stores the delta change in cost and threshold after
558 // accounting for the given instruction. The map is filled only with the
559 // flag PrintInstructionComments on.
560 DenseMap<const Instruction *, InstructionCostDetail> InstructionCostDetailMap;
561
562 /// Upper bound for the inlining cost. Bonuses are being applied to account
563 /// for speculative "expected profit" of the inlining decision.
564 int Threshold = 0;
565
566 /// The amount of StaticBonus applied.
567 int StaticBonusApplied = 0;
568
569 /// Attempt to evaluate indirect calls to boost its inline cost.
570 const bool BoostIndirectCalls;
571
572 /// Ignore the threshold when finalizing analysis.
573 const bool IgnoreThreshold;
574
575 // True if the cost-benefit-analysis-based inliner is enabled.
576 const bool CostBenefitAnalysisEnabled;
577
578 /// Inlining cost measured in abstract units, accounts for all the
579 /// instructions expected to be executed for a given function invocation.
580 /// Instructions that are statically proven to be dead based on call-site
581 /// arguments are not counted here.
582 int Cost = 0;
583
584 // The cumulative cost at the beginning of the basic block being analyzed. At
585 // the end of analyzing each basic block, "Cost - CostAtBBStart" represents
586 // the size of that basic block.
587 int CostAtBBStart = 0;
588
589 // The static size of live but cold basic blocks. This is "static" in the
590 // sense that it's not weighted by profile counts at all.
591 int ColdSize = 0;
592
593 // Whether inlining is decided by cost-threshold analysis.
594 bool DecidedByCostThreshold = false;
595
596 // Whether inlining is decided by cost-benefit analysis.
597 bool DecidedByCostBenefit = false;
598
599 // The cost-benefit pair computed by cost-benefit analysis.
600 std::optional<CostBenefitPair> CostBenefit;
601
602 bool SingleBB = true;
603
604 unsigned SROACostSavings = 0;
605 unsigned SROACostSavingsLost = 0;
606
607 /// The mapping of caller Alloca values to their accumulated cost savings. If
608 /// we have to disable SROA for one of the allocas, this tells us how much
609 /// cost must be added.
610 DenseMap<AllocaInst *, int> SROAArgCosts;
611
612 /// Return true if \p Call is a cold callsite.
613 bool isColdCallSite(CallBase &Call, BlockFrequencyInfo *CallerBFI);
614
615 /// Update Threshold based on callsite properties such as callee
616 /// attributes and callee hotness for PGO builds. The Callee is explicitly
617 /// passed to support analyzing indirect calls whose target is inferred by
618 /// analysis.
619 void updateThreshold(CallBase &Call, Function &Callee);
620 /// Return a higher threshold if \p Call is a hot callsite.
621 std::optional<int> getHotCallSiteThreshold(CallBase &Call,
622 BlockFrequencyInfo *CallerBFI);
623
624 /// Handle a capped 'int' increment for Cost.
625 void addCost(int64_t Inc) {
626 Inc = std::clamp<int64_t>(val: Inc, INT_MIN, INT_MAX);
627 Cost = std::clamp<int64_t>(val: Inc + Cost, INT_MIN, INT_MAX);
628 }
629
630 void onDisableSROA(AllocaInst *Arg) override {
631 auto CostIt = SROAArgCosts.find(Val: Arg);
632 if (CostIt == SROAArgCosts.end())
633 return;
634 addCost(Inc: CostIt->second);
635 SROACostSavings -= CostIt->second;
636 SROACostSavingsLost += CostIt->second;
637 SROAArgCosts.erase(I: CostIt);
638 }
639
640 void onDisableLoadElimination() override {
641 addCost(Inc: LoadEliminationCost);
642 LoadEliminationCost = 0;
643 }
644
645 bool onCallBaseVisitStart(CallBase &Call) override {
646 if (std::optional<int> AttrCallThresholdBonus =
647 getStringFnAttrAsInt(CB&: Call, AttrKind: "call-threshold-bonus"))
648 Threshold += *AttrCallThresholdBonus;
649
650 if (std::optional<int> AttrCallCost =
651 getStringFnAttrAsInt(CB&: Call, AttrKind: "call-inline-cost")) {
652 addCost(Inc: *AttrCallCost);
653 // Prevent further processing of the call since we want to override its
654 // inline cost, not just add to it.
655 return false;
656 }
657 return true;
658 }
659
660 void onCallPenalty() override { addCost(Inc: CallPenalty); }
661
662 void onMemAccess() override { addCost(Inc: MemAccessCost); }
663
664 void onCallArgumentSetup(const CallBase &Call) override {
665 // Pay the price of the argument setup. We account for the average 1
666 // instruction per call argument setup here.
667 addCost(Inc: Call.arg_size() * InstrCost);
668 }
669 void onLoadRelativeIntrinsic() override {
670 // This is normally lowered to 4 LLVM instructions.
671 addCost(Inc: 3 * InstrCost);
672 }
673 void onLoweredCall(Function *F, CallBase &Call,
674 bool IsIndirectCall) override {
675 // We account for the average 1 instruction per call argument setup here.
676 addCost(Inc: Call.arg_size() * InstrCost);
677
678 // If we have a constant that we are calling as a function, we can peer
679 // through it and see the function target. This happens not infrequently
680 // during devirtualization and so we want to give it a hefty bonus for
681 // inlining, but cap that bonus in the event that inlining wouldn't pan out.
682 // Pretend to inline the function, with a custom threshold.
683 if (IsIndirectCall && BoostIndirectCalls) {
684 auto IndirectCallParams = Params;
685 IndirectCallParams.DefaultThreshold =
686 InlineConstants::IndirectCallThreshold;
687 /// FIXME: if InlineCostCallAnalyzer is derived from, this may need
688 /// to instantiate the derived class.
689 InlineCostCallAnalyzer CA(*F, Call, IndirectCallParams, TTI,
690 GetAssumptionCache, GetBFI, PSI, ORE, false);
691 if (CA.analyze().isSuccess()) {
692 // We were able to inline the indirect call! Subtract the cost from the
693 // threshold to get the bonus we want to apply, but don't go below zero.
694 Cost -= std::max(a: 0, b: CA.getThreshold() - CA.getCost());
695 }
696 } else
697 // Otherwise simply add the cost for merely making the call.
698 addCost(Inc: TTI.getInlineCallPenalty(F: CandidateCall.getCaller(), Call,
699 DefaultCallPenalty: CallPenalty));
700 }
701
702 void onFinalizeSwitch(unsigned JumpTableSize, unsigned NumCaseCluster,
703 bool DefaultDestUndefined) override {
704 // If suitable for a jump table, consider the cost for the table size and
705 // branch to destination.
706 // Maximum valid cost increased in this function.
707 if (JumpTableSize) {
708 // Suppose a default branch includes one compare and one conditional
709 // branch if it's reachable.
710 if (!DefaultDestUndefined)
711 addCost(Inc: 2 * InstrCost);
712 // Suppose a jump table requires one load and one jump instruction.
713 int64_t JTCost =
714 static_cast<int64_t>(JumpTableSize) * InstrCost + 2 * InstrCost;
715 addCost(Inc: JTCost);
716 return;
717 }
718
719 if (NumCaseCluster <= 3) {
720 // Suppose a comparison includes one compare and one conditional branch.
721 // We can reduce a set of instructions if the default branch is
722 // undefined.
723 addCost(Inc: (NumCaseCluster - DefaultDestUndefined) * 2 * InstrCost);
724 return;
725 }
726
727 int64_t ExpectedNumberOfCompare =
728 getExpectedNumberOfCompare(NumCaseCluster);
729 int64_t SwitchCost = ExpectedNumberOfCompare * 2 * InstrCost;
730
731 addCost(Inc: SwitchCost);
732 }
733 void onMissedSimplification() override { addCost(Inc: InstrCost); }
734
735 void onInitializeSROAArg(AllocaInst *Arg) override {
736 assert(Arg != nullptr &&
737 "Should not initialize SROA costs for null value.");
738 auto SROAArgCost = TTI.getCallerAllocaCost(CB: &CandidateCall, AI: Arg);
739 SROACostSavings += SROAArgCost;
740 SROAArgCosts[Arg] = SROAArgCost;
741 }
742
743 void onAggregateSROAUse(AllocaInst *SROAArg) override {
744 auto CostIt = SROAArgCosts.find(Val: SROAArg);
745 assert(CostIt != SROAArgCosts.end() &&
746 "expected this argument to have a cost");
747 CostIt->second += InstrCost;
748 SROACostSavings += InstrCost;
749 }
750
751 void onBlockStart(const BasicBlock *BB) override { CostAtBBStart = Cost; }
752
753 void onBlockAnalyzed(const BasicBlock *BB) override {
754 if (CostBenefitAnalysisEnabled) {
755 // Keep track of the static size of live but cold basic blocks. For now,
756 // we define a cold basic block to be one that's never executed.
757 assert(GetBFI && "GetBFI must be available");
758 BlockFrequencyInfo *BFI = &(GetBFI(F));
759 assert(BFI && "BFI must be available");
760 auto ProfileCount = BFI->getBlockProfileCount(BB);
761 if (*ProfileCount == 0)
762 ColdSize += Cost - CostAtBBStart;
763 }
764
765 auto *TI = BB->getTerminator();
766 // If we had any successors at this point, than post-inlining is likely to
767 // have them as well. Note that we assume any basic blocks which existed
768 // due to branches or switches which folded above will also fold after
769 // inlining.
770 if (SingleBB && TI->getNumSuccessors() > 1) {
771 // Take off the bonus we applied to the threshold.
772 Threshold -= SingleBBBonus;
773 SingleBB = false;
774 }
775 }
776
777 void onInstructionAnalysisStart(const Instruction *I) override {
778 // This function is called to store the initial cost of inlining before
779 // the given instruction was assessed.
780 if (!PrintInstructionComments)
781 return;
782 InstructionCostDetailMap[I].CostBefore = Cost;
783 InstructionCostDetailMap[I].ThresholdBefore = Threshold;
784 }
785
786 void onInstructionAnalysisFinish(const Instruction *I) override {
787 // This function is called to find new values of cost and threshold after
788 // the instruction has been assessed.
789 if (!PrintInstructionComments)
790 return;
791 InstructionCostDetailMap[I].CostAfter = Cost;
792 InstructionCostDetailMap[I].ThresholdAfter = Threshold;
793 }
794
795 bool isCostBenefitAnalysisEnabled() {
796 if (!PSI || !PSI->hasProfileSummary())
797 return false;
798
799 if (!GetBFI)
800 return false;
801
802 if (InlineEnableCostBenefitAnalysis.getNumOccurrences()) {
803 // Honor the explicit request from the user.
804 if (!InlineEnableCostBenefitAnalysis)
805 return false;
806 } else {
807 // Otherwise, require instrumentation profile.
808 if (!PSI->hasInstrumentationProfile())
809 return false;
810 }
811
812 auto *Caller = CandidateCall.getParent()->getParent();
813 if (!Caller->getEntryCount())
814 return false;
815
816 BlockFrequencyInfo *CallerBFI = &(GetBFI(*Caller));
817 if (!CallerBFI)
818 return false;
819
820 // For now, limit to hot call site.
821 if (!PSI->isHotCallSite(CB: CandidateCall, BFI: CallerBFI))
822 return false;
823
824 // Make sure we have a nonzero entry count.
825 auto EntryCount = F.getEntryCount();
826 if (!EntryCount || !EntryCount->getCount())
827 return false;
828
829 BlockFrequencyInfo *CalleeBFI = &(GetBFI(F));
830 if (!CalleeBFI)
831 return false;
832
833 return true;
834 }
835
836 // A helper function to choose between command line override and default.
837 unsigned getInliningCostBenefitAnalysisSavingsMultiplier() const {
838 if (InlineSavingsMultiplier.getNumOccurrences())
839 return InlineSavingsMultiplier;
840 return TTI.getInliningCostBenefitAnalysisSavingsMultiplier();
841 }
842
843 // A helper function to choose between command line override and default.
844 unsigned getInliningCostBenefitAnalysisProfitableMultiplier() const {
845 if (InlineSavingsProfitableMultiplier.getNumOccurrences())
846 return InlineSavingsProfitableMultiplier;
847 return TTI.getInliningCostBenefitAnalysisProfitableMultiplier();
848 }
849
850 void OverrideCycleSavingsAndSizeForTesting(APInt &CycleSavings, int &Size) {
851 if (std::optional<int> AttrCycleSavings = getStringFnAttrAsInt(
852 CB&: CandidateCall, AttrKind: "inline-cycle-savings-for-test")) {
853 CycleSavings = *AttrCycleSavings;
854 }
855
856 if (std::optional<int> AttrRuntimeCost = getStringFnAttrAsInt(
857 CB&: CandidateCall, AttrKind: "inline-runtime-cost-for-test")) {
858 Size = *AttrRuntimeCost;
859 }
860 }
861
862 // Determine whether we should inline the given call site, taking into account
863 // both the size cost and the cycle savings. Return std::nullopt if we don't
864 // have sufficient profiling information to determine.
865 std::optional<bool> costBenefitAnalysis() {
866 if (!CostBenefitAnalysisEnabled)
867 return std::nullopt;
868
869 // buildInlinerPipeline in the pass builder sets HotCallSiteThreshold to 0
870 // for the prelink phase of the AutoFDO + ThinLTO build. Honor the logic by
871 // falling back to the cost-based metric.
872 // TODO: Improve this hacky condition.
873 if (Threshold == 0)
874 return std::nullopt;
875
876 assert(GetBFI);
877 BlockFrequencyInfo *CalleeBFI = &(GetBFI(F));
878 assert(CalleeBFI);
879
880 // The cycle savings expressed as the sum of InstrCost
881 // multiplied by the estimated dynamic count of each instruction we can
882 // avoid. Savings come from the call site cost, such as argument setup and
883 // the call instruction, as well as the instructions that are folded.
884 //
885 // We use 128-bit APInt here to avoid potential overflow. This variable
886 // should stay well below 10^^24 (or 2^^80) in practice. This "worst" case
887 // assumes that we can avoid or fold a billion instructions, each with a
888 // profile count of 10^^15 -- roughly the number of cycles for a 24-hour
889 // period on a 4GHz machine.
890 APInt CycleSavings(128, 0);
891
892 for (auto &BB : F) {
893 APInt CurrentSavings(128, 0);
894 for (auto &I : BB) {
895 if (BranchInst *BI = dyn_cast<BranchInst>(Val: &I)) {
896 // Count a conditional branch as savings if it becomes unconditional.
897 if (BI->isConditional() &&
898 isa_and_nonnull<ConstantInt>(
899 Val: SimplifiedValues.lookup(Val: BI->getCondition()))) {
900 CurrentSavings += InstrCost;
901 }
902 } else if (SwitchInst *SI = dyn_cast<SwitchInst>(Val: &I)) {
903 if (isa_and_present<ConstantInt>(Val: SimplifiedValues.lookup(Val: SI->getCondition())))
904 CurrentSavings += InstrCost;
905 } else if (Value *V = dyn_cast<Value>(Val: &I)) {
906 // Count an instruction as savings if we can fold it.
907 if (SimplifiedValues.count(Val: V)) {
908 CurrentSavings += InstrCost;
909 }
910 }
911 }
912
913 auto ProfileCount = CalleeBFI->getBlockProfileCount(BB: &BB);
914 CurrentSavings *= *ProfileCount;
915 CycleSavings += CurrentSavings;
916 }
917
918 // Compute the cycle savings per call.
919 auto EntryProfileCount = F.getEntryCount();
920 assert(EntryProfileCount && EntryProfileCount->getCount());
921 auto EntryCount = EntryProfileCount->getCount();
922 CycleSavings += EntryCount / 2;
923 CycleSavings = CycleSavings.udiv(RHS: EntryCount);
924
925 // Compute the total savings for the call site.
926 auto *CallerBB = CandidateCall.getParent();
927 BlockFrequencyInfo *CallerBFI = &(GetBFI(*(CallerBB->getParent())));
928 CycleSavings += getCallsiteCost(TTI, Call: this->CandidateCall, DL);
929 CycleSavings *= *CallerBFI->getBlockProfileCount(BB: CallerBB);
930
931 // Remove the cost of the cold basic blocks to model the runtime cost more
932 // accurately. Both machine block placement and function splitting could
933 // place cold blocks further from hot blocks.
934 int Size = Cost - ColdSize;
935
936 // Allow tiny callees to be inlined regardless of whether they meet the
937 // savings threshold.
938 Size = Size > InlineSizeAllowance ? Size - InlineSizeAllowance : 1;
939
940 OverrideCycleSavingsAndSizeForTesting(CycleSavings, Size);
941 CostBenefit.emplace(args: APInt(128, Size), args&: CycleSavings);
942
943 // Let R be the ratio of CycleSavings to Size. We accept the inlining
944 // opportunity if R is really high and reject if R is really low. If R is
945 // somewhere in the middle, we fall back to the cost-based analysis.
946 //
947 // Specifically, let R = CycleSavings / Size, we accept the inlining
948 // opportunity if:
949 //
950 // PSI->getOrCompHotCountThreshold()
951 // R > -------------------------------------------------
952 // getInliningCostBenefitAnalysisSavingsMultiplier()
953 //
954 // and reject the inlining opportunity if:
955 //
956 // PSI->getOrCompHotCountThreshold()
957 // R <= ----------------------------------------------------
958 // getInliningCostBenefitAnalysisProfitableMultiplier()
959 //
960 // Otherwise, we fall back to the cost-based analysis.
961 //
962 // Implementation-wise, use multiplication (CycleSavings * Multiplier,
963 // HotCountThreshold * Size) rather than division to avoid precision loss.
964 APInt Threshold(128, PSI->getOrCompHotCountThreshold());
965 Threshold *= Size;
966
967 APInt UpperBoundCycleSavings = CycleSavings;
968 UpperBoundCycleSavings *= getInliningCostBenefitAnalysisSavingsMultiplier();
969 if (UpperBoundCycleSavings.uge(RHS: Threshold))
970 return true;
971
972 APInt LowerBoundCycleSavings = CycleSavings;
973 LowerBoundCycleSavings *=
974 getInliningCostBenefitAnalysisProfitableMultiplier();
975 if (LowerBoundCycleSavings.ult(RHS: Threshold))
976 return false;
977
978 // Otherwise, fall back to the cost-based analysis.
979 return std::nullopt;
980 }
981
982 InlineResult finalizeAnalysis() override {
983 // Loops generally act a lot like calls in that they act like barriers to
984 // movement, require a certain amount of setup, etc. So when optimising for
985 // size, we penalise any call sites that perform loops. We do this after all
986 // other costs here, so will likely only be dealing with relatively small
987 // functions (and hence DT and LI will hopefully be cheap).
988 auto *Caller = CandidateCall.getFunction();
989 if (Caller->hasMinSize()) {
990 DominatorTree DT(F);
991 LoopInfo LI(DT);
992 int NumLoops = 0;
993 for (Loop *L : LI) {
994 // Ignore loops that will not be executed
995 if (DeadBlocks.count(Ptr: L->getHeader()))
996 continue;
997 NumLoops++;
998 }
999 addCost(Inc: NumLoops * InlineConstants::LoopPenalty);
1000 }
1001
1002 // We applied the maximum possible vector bonus at the beginning. Now,
1003 // subtract the excess bonus, if any, from the Threshold before
1004 // comparing against Cost.
1005 if (NumVectorInstructions <= NumInstructions / 10)
1006 Threshold -= VectorBonus;
1007 else if (NumVectorInstructions <= NumInstructions / 2)
1008 Threshold -= VectorBonus / 2;
1009
1010 if (std::optional<int> AttrCost =
1011 getStringFnAttrAsInt(CB&: CandidateCall, AttrKind: "function-inline-cost"))
1012 Cost = *AttrCost;
1013
1014 if (std::optional<int> AttrCostMult = getStringFnAttrAsInt(
1015 CB&: CandidateCall,
1016 AttrKind: InlineConstants::FunctionInlineCostMultiplierAttributeName))
1017 Cost *= *AttrCostMult;
1018
1019 if (std::optional<int> AttrThreshold =
1020 getStringFnAttrAsInt(CB&: CandidateCall, AttrKind: "function-inline-threshold"))
1021 Threshold = *AttrThreshold;
1022
1023 if (auto Result = costBenefitAnalysis()) {
1024 DecidedByCostBenefit = true;
1025 if (*Result)
1026 return InlineResult::success();
1027 else
1028 return InlineResult::failure(Reason: "Cost over threshold.");
1029 }
1030
1031 if (IgnoreThreshold)
1032 return InlineResult::success();
1033
1034 DecidedByCostThreshold = true;
1035 return Cost < std::max(a: 1, b: Threshold)
1036 ? InlineResult::success()
1037 : InlineResult::failure(Reason: "Cost over threshold.");
1038 }
1039
1040 bool shouldStop() override {
1041 if (IgnoreThreshold || ComputeFullInlineCost)
1042 return false;
1043 // Bail out the moment we cross the threshold. This means we'll under-count
1044 // the cost, but only when undercounting doesn't matter.
1045 if (Cost < Threshold)
1046 return false;
1047 DecidedByCostThreshold = true;
1048 return true;
1049 }
1050
1051 void onLoadEliminationOpportunity() override {
1052 LoadEliminationCost += InstrCost;
1053 }
1054
1055 InlineResult onAnalysisStart() override {
1056 // Perform some tweaks to the cost and threshold based on the direct
1057 // callsite information.
1058
1059 // We want to more aggressively inline vector-dense kernels, so up the
1060 // threshold, and we'll lower it if the % of vector instructions gets too
1061 // low. Note that these bonuses are some what arbitrary and evolved over
1062 // time by accident as much as because they are principled bonuses.
1063 //
1064 // FIXME: It would be nice to remove all such bonuses. At least it would be
1065 // nice to base the bonus values on something more scientific.
1066 assert(NumInstructions == 0);
1067 assert(NumVectorInstructions == 0);
1068
1069 // Update the threshold based on callsite properties
1070 updateThreshold(Call&: CandidateCall, Callee&: F);
1071
1072 // While Threshold depends on commandline options that can take negative
1073 // values, we want to enforce the invariant that the computed threshold and
1074 // bonuses are non-negative.
1075 assert(Threshold >= 0);
1076 assert(SingleBBBonus >= 0);
1077 assert(VectorBonus >= 0);
1078
1079 // Speculatively apply all possible bonuses to Threshold. If cost exceeds
1080 // this Threshold any time, and cost cannot decrease, we can stop processing
1081 // the rest of the function body.
1082 Threshold += (SingleBBBonus + VectorBonus);
1083
1084 // Give out bonuses for the callsite, as the instructions setting them up
1085 // will be gone after inlining.
1086 addCost(Inc: -getCallsiteCost(TTI, Call: this->CandidateCall, DL));
1087
1088 // If this function uses the coldcc calling convention, prefer not to inline
1089 // it.
1090 if (F.getCallingConv() == CallingConv::Cold)
1091 Cost += InlineConstants::ColdccPenalty;
1092
1093 LLVM_DEBUG(dbgs() << " Initial cost: " << Cost << "\n");
1094
1095 // Check if we're done. This can happen due to bonuses and penalties.
1096 if (Cost >= Threshold && !ComputeFullInlineCost)
1097 return InlineResult::failure(Reason: "high cost");
1098
1099 return InlineResult::success();
1100 }
1101
1102public:
1103 InlineCostCallAnalyzer(
1104 Function &Callee, CallBase &Call, const InlineParams &Params,
1105 const TargetTransformInfo &TTI,
1106 function_ref<AssumptionCache &(Function &)> GetAssumptionCache,
1107 function_ref<BlockFrequencyInfo &(Function &)> GetBFI = nullptr,
1108 ProfileSummaryInfo *PSI = nullptr,
1109 OptimizationRemarkEmitter *ORE = nullptr, bool BoostIndirect = true,
1110 bool IgnoreThreshold = false)
1111 : CallAnalyzer(Callee, Call, TTI, GetAssumptionCache, GetBFI, PSI, ORE),
1112 ComputeFullInlineCost(OptComputeFullInlineCost ||
1113 Params.ComputeFullInlineCost || ORE ||
1114 isCostBenefitAnalysisEnabled()),
1115 Params(Params), Threshold(Params.DefaultThreshold),
1116 BoostIndirectCalls(BoostIndirect), IgnoreThreshold(IgnoreThreshold),
1117 CostBenefitAnalysisEnabled(isCostBenefitAnalysisEnabled()),
1118 Writer(this) {
1119 AllowRecursiveCall = *Params.AllowRecursiveCall;
1120 }
1121
1122 /// Annotation Writer for instruction details
1123 InlineCostAnnotationWriter Writer;
1124
1125 void dump();
1126
1127 // Prints the same analysis as dump(), but its definition is not dependent
1128 // on the build.
1129 void print(raw_ostream &OS);
1130
1131 std::optional<InstructionCostDetail> getCostDetails(const Instruction *I) {
1132 if (InstructionCostDetailMap.contains(Val: I))
1133 return InstructionCostDetailMap[I];
1134 return std::nullopt;
1135 }
1136
1137 virtual ~InlineCostCallAnalyzer() = default;
1138 int getThreshold() const { return Threshold; }
1139 int getCost() const { return Cost; }
1140 int getStaticBonusApplied() const { return StaticBonusApplied; }
1141 std::optional<CostBenefitPair> getCostBenefitPair() { return CostBenefit; }
1142 bool wasDecidedByCostBenefit() const { return DecidedByCostBenefit; }
1143 bool wasDecidedByCostThreshold() const { return DecidedByCostThreshold; }
1144};
1145
1146// Return true if CB is the sole call to local function Callee.
1147static bool isSoleCallToLocalFunction(const CallBase &CB,
1148 const Function &Callee) {
1149 return Callee.hasLocalLinkage() && Callee.hasOneLiveUse() &&
1150 &Callee == CB.getCalledFunction();
1151}
1152
1153class InlineCostFeaturesAnalyzer final : public CallAnalyzer {
1154private:
1155 InlineCostFeatures Cost = {};
1156
1157 // FIXME: These constants are taken from the heuristic-based cost visitor.
1158 // These should be removed entirely in a later revision to avoid reliance on
1159 // heuristics in the ML inliner.
1160 static constexpr int JTCostMultiplier = 2;
1161 static constexpr int CaseClusterCostMultiplier = 2;
1162 static constexpr int SwitchDefaultDestCostMultiplier = 2;
1163 static constexpr int SwitchCostMultiplier = 2;
1164
1165 // FIXME: These are taken from the heuristic-based cost visitor: we should
1166 // eventually abstract these to the CallAnalyzer to avoid duplication.
1167 unsigned SROACostSavingOpportunities = 0;
1168 int VectorBonus = 0;
1169 int SingleBBBonus = 0;
1170 int Threshold = 5;
1171
1172 DenseMap<AllocaInst *, unsigned> SROACosts;
1173
1174 void increment(InlineCostFeatureIndex Feature, int64_t Delta = 1) {
1175 Cost[static_cast<size_t>(Feature)] += Delta;
1176 }
1177
1178 void set(InlineCostFeatureIndex Feature, int64_t Value) {
1179 Cost[static_cast<size_t>(Feature)] = Value;
1180 }
1181
1182 void onDisableSROA(AllocaInst *Arg) override {
1183 auto CostIt = SROACosts.find(Val: Arg);
1184 if (CostIt == SROACosts.end())
1185 return;
1186
1187 increment(Feature: InlineCostFeatureIndex::sroa_losses, Delta: CostIt->second);
1188 SROACostSavingOpportunities -= CostIt->second;
1189 SROACosts.erase(I: CostIt);
1190 }
1191
1192 void onDisableLoadElimination() override {
1193 set(Feature: InlineCostFeatureIndex::load_elimination, Value: 1);
1194 }
1195
1196 void onCallPenalty() override {
1197 increment(Feature: InlineCostFeatureIndex::call_penalty, Delta: CallPenalty);
1198 }
1199
1200 void onCallArgumentSetup(const CallBase &Call) override {
1201 increment(Feature: InlineCostFeatureIndex::call_argument_setup,
1202 Delta: Call.arg_size() * InstrCost);
1203 }
1204
1205 void onLoadRelativeIntrinsic() override {
1206 increment(Feature: InlineCostFeatureIndex::load_relative_intrinsic, Delta: 3 * InstrCost);
1207 }
1208
1209 void onLoweredCall(Function *F, CallBase &Call,
1210 bool IsIndirectCall) override {
1211 increment(Feature: InlineCostFeatureIndex::lowered_call_arg_setup,
1212 Delta: Call.arg_size() * InstrCost);
1213
1214 if (IsIndirectCall) {
1215 InlineParams IndirectCallParams = {/* DefaultThreshold*/ 0,
1216 /*HintThreshold*/ {},
1217 /*ColdThreshold*/ {},
1218 /*OptSizeThreshold*/ {},
1219 /*OptMinSizeThreshold*/ {},
1220 /*HotCallSiteThreshold*/ {},
1221 /*LocallyHotCallSiteThreshold*/ {},
1222 /*ColdCallSiteThreshold*/ {},
1223 /*ComputeFullInlineCost*/ true,
1224 /*EnableDeferral*/ true};
1225 IndirectCallParams.DefaultThreshold =
1226 InlineConstants::IndirectCallThreshold;
1227
1228 InlineCostCallAnalyzer CA(*F, Call, IndirectCallParams, TTI,
1229 GetAssumptionCache, GetBFI, PSI, ORE, false,
1230 true);
1231 if (CA.analyze().isSuccess()) {
1232 increment(Feature: InlineCostFeatureIndex::nested_inline_cost_estimate,
1233 Delta: CA.getCost());
1234 increment(Feature: InlineCostFeatureIndex::nested_inlines, Delta: 1);
1235 }
1236 } else {
1237 onCallPenalty();
1238 }
1239 }
1240
1241 void onFinalizeSwitch(unsigned JumpTableSize, unsigned NumCaseCluster,
1242 bool DefaultDestUndefined) override {
1243 if (JumpTableSize) {
1244 if (!DefaultDestUndefined)
1245 increment(Feature: InlineCostFeatureIndex::switch_default_dest_penalty,
1246 Delta: SwitchDefaultDestCostMultiplier * InstrCost);
1247 int64_t JTCost = static_cast<int64_t>(JumpTableSize) * InstrCost +
1248 JTCostMultiplier * InstrCost;
1249 increment(Feature: InlineCostFeatureIndex::jump_table_penalty, Delta: JTCost);
1250 return;
1251 }
1252
1253 if (NumCaseCluster <= 3) {
1254 increment(Feature: InlineCostFeatureIndex::case_cluster_penalty,
1255 Delta: (NumCaseCluster - DefaultDestUndefined) *
1256 CaseClusterCostMultiplier * InstrCost);
1257 return;
1258 }
1259
1260 int64_t ExpectedNumberOfCompare =
1261 getExpectedNumberOfCompare(NumCaseCluster);
1262
1263 int64_t SwitchCost =
1264 ExpectedNumberOfCompare * SwitchCostMultiplier * InstrCost;
1265 increment(Feature: InlineCostFeatureIndex::switch_penalty, Delta: SwitchCost);
1266 }
1267
1268 void onMissedSimplification() override {
1269 increment(Feature: InlineCostFeatureIndex::unsimplified_common_instructions,
1270 Delta: InstrCost);
1271 }
1272
1273 void onInitializeSROAArg(AllocaInst *Arg) override {
1274 auto SROAArgCost = TTI.getCallerAllocaCost(CB: &CandidateCall, AI: Arg);
1275 SROACosts[Arg] = SROAArgCost;
1276 SROACostSavingOpportunities += SROAArgCost;
1277 }
1278
1279 void onAggregateSROAUse(AllocaInst *Arg) override {
1280 SROACosts.find(Val: Arg)->second += InstrCost;
1281 SROACostSavingOpportunities += InstrCost;
1282 }
1283
1284 void onBlockAnalyzed(const BasicBlock *BB) override {
1285 if (BB->getTerminator()->getNumSuccessors() > 1)
1286 set(Feature: InlineCostFeatureIndex::is_multiple_blocks, Value: 1);
1287 Threshold -= SingleBBBonus;
1288 }
1289
1290 InlineResult finalizeAnalysis() override {
1291 auto *Caller = CandidateCall.getFunction();
1292 if (Caller->hasMinSize()) {
1293 DominatorTree DT(F);
1294 LoopInfo LI(DT);
1295 for (Loop *L : LI) {
1296 // Ignore loops that will not be executed
1297 if (DeadBlocks.count(Ptr: L->getHeader()))
1298 continue;
1299 increment(Feature: InlineCostFeatureIndex::num_loops,
1300 Delta: InlineConstants::LoopPenalty);
1301 }
1302 }
1303 set(Feature: InlineCostFeatureIndex::dead_blocks, Value: DeadBlocks.size());
1304 set(Feature: InlineCostFeatureIndex::simplified_instructions,
1305 Value: NumInstructionsSimplified);
1306 set(Feature: InlineCostFeatureIndex::constant_args, Value: NumConstantArgs);
1307 set(Feature: InlineCostFeatureIndex::constant_offset_ptr_args,
1308 Value: NumConstantOffsetPtrArgs);
1309 set(Feature: InlineCostFeatureIndex::sroa_savings, Value: SROACostSavingOpportunities);
1310
1311 if (NumVectorInstructions <= NumInstructions / 10)
1312 Threshold -= VectorBonus;
1313 else if (NumVectorInstructions <= NumInstructions / 2)
1314 Threshold -= VectorBonus / 2;
1315
1316 set(Feature: InlineCostFeatureIndex::threshold, Value: Threshold);
1317
1318 return InlineResult::success();
1319 }
1320
1321 bool shouldStop() override { return false; }
1322
1323 void onLoadEliminationOpportunity() override {
1324 increment(Feature: InlineCostFeatureIndex::load_elimination, Delta: 1);
1325 }
1326
1327 InlineResult onAnalysisStart() override {
1328 increment(Feature: InlineCostFeatureIndex::callsite_cost,
1329 Delta: -1 * getCallsiteCost(TTI, Call: this->CandidateCall, DL));
1330
1331 set(Feature: InlineCostFeatureIndex::cold_cc_penalty,
1332 Value: (F.getCallingConv() == CallingConv::Cold));
1333
1334 set(Feature: InlineCostFeatureIndex::last_call_to_static_bonus,
1335 Value: isSoleCallToLocalFunction(CB: CandidateCall, Callee: F));
1336
1337 // FIXME: we shouldn't repeat this logic in both the Features and Cost
1338 // analyzer - instead, we should abstract it to a common method in the
1339 // CallAnalyzer
1340 int SingleBBBonusPercent = 50;
1341 int VectorBonusPercent = TTI.getInlinerVectorBonusPercent();
1342 Threshold += TTI.adjustInliningThreshold(CB: &CandidateCall);
1343 Threshold *= TTI.getInliningThresholdMultiplier();
1344 SingleBBBonus = Threshold * SingleBBBonusPercent / 100;
1345 VectorBonus = Threshold * VectorBonusPercent / 100;
1346 Threshold += (SingleBBBonus + VectorBonus);
1347
1348 return InlineResult::success();
1349 }
1350
1351public:
1352 InlineCostFeaturesAnalyzer(
1353 const TargetTransformInfo &TTI,
1354 function_ref<AssumptionCache &(Function &)> &GetAssumptionCache,
1355 function_ref<BlockFrequencyInfo &(Function &)> GetBFI,
1356 ProfileSummaryInfo *PSI, OptimizationRemarkEmitter *ORE, Function &Callee,
1357 CallBase &Call)
1358 : CallAnalyzer(Callee, Call, TTI, GetAssumptionCache, GetBFI, PSI) {}
1359
1360 const InlineCostFeatures &features() const { return Cost; }
1361};
1362
1363} // namespace
1364
1365/// Test whether the given value is an Alloca-derived function argument.
1366bool CallAnalyzer::isAllocaDerivedArg(Value *V) {
1367 return SROAArgValues.count(Val: V);
1368}
1369
1370void CallAnalyzer::disableSROAForArg(AllocaInst *SROAArg) {
1371 onDisableSROA(Arg: SROAArg);
1372 EnabledSROAAllocas.erase(V: SROAArg);
1373 disableLoadElimination();
1374}
1375
1376void InlineCostAnnotationWriter::emitInstructionAnnot(
1377 const Instruction *I, formatted_raw_ostream &OS) {
1378 // The cost of inlining of the given instruction is printed always.
1379 // The threshold delta is printed only when it is non-zero. It happens
1380 // when we decided to give a bonus at a particular instruction.
1381 std::optional<InstructionCostDetail> Record = ICCA->getCostDetails(I);
1382 if (!Record)
1383 OS << "; No analysis for the instruction";
1384 else {
1385 OS << "; cost before = " << Record->CostBefore
1386 << ", cost after = " << Record->CostAfter
1387 << ", threshold before = " << Record->ThresholdBefore
1388 << ", threshold after = " << Record->ThresholdAfter << ", ";
1389 OS << "cost delta = " << Record->getCostDelta();
1390 if (Record->hasThresholdChanged())
1391 OS << ", threshold delta = " << Record->getThresholdDelta();
1392 }
1393 auto C = ICCA->getSimplifiedValue(I: const_cast<Instruction *>(I));
1394 if (C) {
1395 OS << ", simplified to ";
1396 (*C)->print(O&: OS, IsForDebug: true);
1397 }
1398 OS << "\n";
1399}
1400
1401/// If 'V' maps to a SROA candidate, disable SROA for it.
1402void CallAnalyzer::disableSROA(Value *V) {
1403 if (auto *SROAArg = getSROAArgForValueOrNull(V)) {
1404 disableSROAForArg(SROAArg);
1405 }
1406}
1407
1408void CallAnalyzer::disableLoadElimination() {
1409 if (EnableLoadElimination) {
1410 onDisableLoadElimination();
1411 EnableLoadElimination = false;
1412 }
1413}
1414
1415/// Accumulate a constant GEP offset into an APInt if possible.
1416///
1417/// Returns false if unable to compute the offset for any reason. Respects any
1418/// simplified values known during the analysis of this callsite.
1419bool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) {
1420 unsigned IntPtrWidth = DL.getIndexTypeSizeInBits(Ty: GEP.getType());
1421 assert(IntPtrWidth == Offset.getBitWidth());
1422
1423 for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP);
1424 GTI != GTE; ++GTI) {
1425 ConstantInt *OpC = dyn_cast<ConstantInt>(Val: GTI.getOperand());
1426 if (!OpC)
1427 if (Constant *SimpleOp = SimplifiedValues.lookup(Val: GTI.getOperand()))
1428 OpC = dyn_cast<ConstantInt>(Val: SimpleOp);
1429 if (!OpC)
1430 return false;
1431 if (OpC->isZero())
1432 continue;
1433
1434 // Handle a struct index, which adds its field offset to the pointer.
1435 if (StructType *STy = GTI.getStructTypeOrNull()) {
1436 unsigned ElementIdx = OpC->getZExtValue();
1437 const StructLayout *SL = DL.getStructLayout(Ty: STy);
1438 Offset += APInt(IntPtrWidth, SL->getElementOffset(Idx: ElementIdx));
1439 continue;
1440 }
1441
1442 APInt TypeSize(IntPtrWidth, GTI.getSequentialElementStride(DL));
1443 Offset += OpC->getValue().sextOrTrunc(width: IntPtrWidth) * TypeSize;
1444 }
1445 return true;
1446}
1447
1448/// Use TTI to check whether a GEP is free.
1449///
1450/// Respects any simplified values known during the analysis of this callsite.
1451bool CallAnalyzer::isGEPFree(GetElementPtrInst &GEP) {
1452 SmallVector<Value *, 4> Operands;
1453 Operands.push_back(Elt: GEP.getOperand(i_nocapture: 0));
1454 for (const Use &Op : GEP.indices())
1455 if (Constant *SimpleOp = SimplifiedValues.lookup(Val: Op))
1456 Operands.push_back(Elt: SimpleOp);
1457 else
1458 Operands.push_back(Elt: Op);
1459 return TTI.getInstructionCost(U: &GEP, Operands,
1460 CostKind: TargetTransformInfo::TCK_SizeAndLatency) ==
1461 TargetTransformInfo::TCC_Free;
1462}
1463
1464bool CallAnalyzer::visitAlloca(AllocaInst &I) {
1465 disableSROA(V: I.getOperand(i_nocapture: 0));
1466
1467 // Check whether inlining will turn a dynamic alloca into a static
1468 // alloca and handle that case.
1469 if (I.isArrayAllocation()) {
1470 Constant *Size = SimplifiedValues.lookup(Val: I.getArraySize());
1471 if (auto *AllocSize = dyn_cast_or_null<ConstantInt>(Val: Size)) {
1472 // Sometimes a dynamic alloca could be converted into a static alloca
1473 // after this constant prop, and become a huge static alloca on an
1474 // unconditional CFG path. Avoid inlining if this is going to happen above
1475 // a threshold.
1476 // FIXME: If the threshold is removed or lowered too much, we could end up
1477 // being too pessimistic and prevent inlining non-problematic code. This
1478 // could result in unintended perf regressions. A better overall strategy
1479 // is needed to track stack usage during inlining.
1480 Type *Ty = I.getAllocatedType();
1481 AllocatedSize = SaturatingMultiplyAdd(
1482 X: AllocSize->getLimitedValue(),
1483 Y: DL.getTypeAllocSize(Ty).getKnownMinValue(), A: AllocatedSize);
1484 if (AllocatedSize > InlineConstants::MaxSimplifiedDynamicAllocaToInline)
1485 HasDynamicAlloca = true;
1486 return false;
1487 }
1488 }
1489
1490 // Accumulate the allocated size.
1491 if (I.isStaticAlloca()) {
1492 Type *Ty = I.getAllocatedType();
1493 AllocatedSize = SaturatingAdd(X: DL.getTypeAllocSize(Ty).getKnownMinValue(),
1494 Y: AllocatedSize);
1495 }
1496
1497 // FIXME: This is overly conservative. Dynamic allocas are inefficient for
1498 // a variety of reasons, and so we would like to not inline them into
1499 // functions which don't currently have a dynamic alloca. This simply
1500 // disables inlining altogether in the presence of a dynamic alloca.
1501 if (!I.isStaticAlloca())
1502 HasDynamicAlloca = true;
1503
1504 return false;
1505}
1506
1507bool CallAnalyzer::visitPHI(PHINode &I) {
1508 // FIXME: We need to propagate SROA *disabling* through phi nodes, even
1509 // though we don't want to propagate it's bonuses. The idea is to disable
1510 // SROA if it *might* be used in an inappropriate manner.
1511
1512 // Phi nodes are always zero-cost.
1513 // FIXME: Pointer sizes may differ between different address spaces, so do we
1514 // need to use correct address space in the call to getPointerSizeInBits here?
1515 // Or could we skip the getPointerSizeInBits call completely? As far as I can
1516 // see the ZeroOffset is used as a dummy value, so we can probably use any
1517 // bit width for the ZeroOffset?
1518 APInt ZeroOffset = APInt::getZero(numBits: DL.getPointerSizeInBits(AS: 0));
1519 bool CheckSROA = I.getType()->isPointerTy();
1520
1521 // Track the constant or pointer with constant offset we've seen so far.
1522 Constant *FirstC = nullptr;
1523 std::pair<Value *, APInt> FirstBaseAndOffset = {nullptr, ZeroOffset};
1524 Value *FirstV = nullptr;
1525
1526 for (unsigned i = 0, e = I.getNumIncomingValues(); i != e; ++i) {
1527 BasicBlock *Pred = I.getIncomingBlock(i);
1528 // If the incoming block is dead, skip the incoming block.
1529 if (DeadBlocks.count(Ptr: Pred))
1530 continue;
1531 // If the parent block of phi is not the known successor of the incoming
1532 // block, skip the incoming block.
1533 BasicBlock *KnownSuccessor = KnownSuccessors[Pred];
1534 if (KnownSuccessor && KnownSuccessor != I.getParent())
1535 continue;
1536
1537 Value *V = I.getIncomingValue(i);
1538 // If the incoming value is this phi itself, skip the incoming value.
1539 if (&I == V)
1540 continue;
1541
1542 Constant *C = dyn_cast<Constant>(Val: V);
1543 if (!C)
1544 C = SimplifiedValues.lookup(Val: V);
1545
1546 std::pair<Value *, APInt> BaseAndOffset = {nullptr, ZeroOffset};
1547 if (!C && CheckSROA)
1548 BaseAndOffset = ConstantOffsetPtrs.lookup(Val: V);
1549
1550 if (!C && !BaseAndOffset.first)
1551 // The incoming value is neither a constant nor a pointer with constant
1552 // offset, exit early.
1553 return true;
1554
1555 if (FirstC) {
1556 if (FirstC == C)
1557 // If we've seen a constant incoming value before and it is the same
1558 // constant we see this time, continue checking the next incoming value.
1559 continue;
1560 // Otherwise early exit because we either see a different constant or saw
1561 // a constant before but we have a pointer with constant offset this time.
1562 return true;
1563 }
1564
1565 if (FirstV) {
1566 // The same logic as above, but check pointer with constant offset here.
1567 if (FirstBaseAndOffset == BaseAndOffset)
1568 continue;
1569 return true;
1570 }
1571
1572 if (C) {
1573 // This is the 1st time we've seen a constant, record it.
1574 FirstC = C;
1575 continue;
1576 }
1577
1578 // The remaining case is that this is the 1st time we've seen a pointer with
1579 // constant offset, record it.
1580 FirstV = V;
1581 FirstBaseAndOffset = BaseAndOffset;
1582 }
1583
1584 // Check if we can map phi to a constant.
1585 if (FirstC) {
1586 SimplifiedValues[&I] = FirstC;
1587 return true;
1588 }
1589
1590 // Check if we can map phi to a pointer with constant offset.
1591 if (FirstBaseAndOffset.first) {
1592 ConstantOffsetPtrs[&I] = FirstBaseAndOffset;
1593
1594 if (auto *SROAArg = getSROAArgForValueOrNull(V: FirstV))
1595 SROAArgValues[&I] = SROAArg;
1596 }
1597
1598 return true;
1599}
1600
1601/// Check we can fold GEPs of constant-offset call site argument pointers.
1602/// This requires target data and inbounds GEPs.
1603///
1604/// \return true if the specified GEP can be folded.
1605bool CallAnalyzer::canFoldInboundsGEP(GetElementPtrInst &I) {
1606 // Check if we have a base + offset for the pointer.
1607 std::pair<Value *, APInt> BaseAndOffset =
1608 ConstantOffsetPtrs.lookup(Val: I.getPointerOperand());
1609 if (!BaseAndOffset.first)
1610 return false;
1611
1612 // Check if the offset of this GEP is constant, and if so accumulate it
1613 // into Offset.
1614 if (!accumulateGEPOffset(GEP&: cast<GEPOperator>(Val&: I), Offset&: BaseAndOffset.second))
1615 return false;
1616
1617 // Add the result as a new mapping to Base + Offset.
1618 ConstantOffsetPtrs[&I] = BaseAndOffset;
1619
1620 return true;
1621}
1622
1623bool CallAnalyzer::visitGetElementPtr(GetElementPtrInst &I) {
1624 auto *SROAArg = getSROAArgForValueOrNull(V: I.getPointerOperand());
1625
1626 // Lambda to check whether a GEP's indices are all constant.
1627 auto IsGEPOffsetConstant = [&](GetElementPtrInst &GEP) {
1628 for (const Use &Op : GEP.indices())
1629 if (!isa<Constant>(Val: Op) && !SimplifiedValues.lookup(Val: Op))
1630 return false;
1631 return true;
1632 };
1633
1634 if (!DisableGEPConstOperand)
1635 if (simplifyInstruction(I))
1636 return true;
1637
1638 if ((I.isInBounds() && canFoldInboundsGEP(I)) || IsGEPOffsetConstant(I)) {
1639 if (SROAArg)
1640 SROAArgValues[&I] = SROAArg;
1641
1642 // Constant GEPs are modeled as free.
1643 return true;
1644 }
1645
1646 // Variable GEPs will require math and will disable SROA.
1647 if (SROAArg)
1648 disableSROAForArg(SROAArg);
1649 return isGEPFree(GEP&: I);
1650}
1651
1652/// Simplify \p I if its operands are constants and update SimplifiedValues.
1653bool CallAnalyzer::simplifyInstruction(Instruction &I) {
1654 SmallVector<Constant *> COps;
1655 for (Value *Op : I.operands()) {
1656 Constant *COp = dyn_cast<Constant>(Val: Op);
1657 if (!COp)
1658 COp = SimplifiedValues.lookup(Val: Op);
1659 if (!COp)
1660 return false;
1661 COps.push_back(Elt: COp);
1662 }
1663 auto *C = ConstantFoldInstOperands(I: &I, Ops: COps, DL);
1664 if (!C)
1665 return false;
1666 SimplifiedValues[&I] = C;
1667 return true;
1668}
1669
1670/// Try to simplify a call to llvm.is.constant.
1671///
1672/// Duplicate the argument checking from CallAnalyzer::simplifyCallSite since
1673/// we expect calls of this specific intrinsic to be infrequent.
1674///
1675/// FIXME: Given that we know CB's parent (F) caller
1676/// (CandidateCall->getParent()->getParent()), we might be able to determine
1677/// whether inlining F into F's caller would change how the call to
1678/// llvm.is.constant would evaluate.
1679bool CallAnalyzer::simplifyIntrinsicCallIsConstant(CallBase &CB) {
1680 Value *Arg = CB.getArgOperand(i: 0);
1681 auto *C = dyn_cast<Constant>(Val: Arg);
1682
1683 if (!C)
1684 C = dyn_cast_or_null<Constant>(Val: SimplifiedValues.lookup(Val: Arg));
1685
1686 Type *RT = CB.getFunctionType()->getReturnType();
1687 SimplifiedValues[&CB] = ConstantInt::get(Ty: RT, V: C ? 1 : 0);
1688 return true;
1689}
1690
1691bool CallAnalyzer::simplifyIntrinsicCallObjectSize(CallBase &CB) {
1692 // As per the langref, "The fourth argument to llvm.objectsize determines if
1693 // the value should be evaluated at runtime."
1694 if (cast<ConstantInt>(Val: CB.getArgOperand(i: 3))->isOne())
1695 return false;
1696
1697 Value *V = lowerObjectSizeCall(ObjectSize: &cast<IntrinsicInst>(Val&: CB), DL, TLI: nullptr,
1698 /*MustSucceed=*/true);
1699 Constant *C = dyn_cast_or_null<Constant>(Val: V);
1700 if (C)
1701 SimplifiedValues[&CB] = C;
1702 return C;
1703}
1704
1705bool CallAnalyzer::visitBitCast(BitCastInst &I) {
1706 // Propagate constants through bitcasts.
1707 if (simplifyInstruction(I))
1708 return true;
1709
1710 // Track base/offsets through casts
1711 std::pair<Value *, APInt> BaseAndOffset =
1712 ConstantOffsetPtrs.lookup(Val: I.getOperand(i_nocapture: 0));
1713 // Casts don't change the offset, just wrap it up.
1714 if (BaseAndOffset.first)
1715 ConstantOffsetPtrs[&I] = BaseAndOffset;
1716
1717 // Also look for SROA candidates here.
1718 if (auto *SROAArg = getSROAArgForValueOrNull(V: I.getOperand(i_nocapture: 0)))
1719 SROAArgValues[&I] = SROAArg;
1720
1721 // Bitcasts are always zero cost.
1722 return true;
1723}
1724
1725bool CallAnalyzer::visitPtrToInt(PtrToIntInst &I) {
1726 // Propagate constants through ptrtoint.
1727 if (simplifyInstruction(I))
1728 return true;
1729
1730 // Track base/offset pairs when converted to a plain integer provided the
1731 // integer is large enough to represent the pointer.
1732 unsigned IntegerSize = I.getType()->getScalarSizeInBits();
1733 unsigned AS = I.getOperand(i_nocapture: 0)->getType()->getPointerAddressSpace();
1734 if (IntegerSize == DL.getPointerSizeInBits(AS)) {
1735 std::pair<Value *, APInt> BaseAndOffset =
1736 ConstantOffsetPtrs.lookup(Val: I.getOperand(i_nocapture: 0));
1737 if (BaseAndOffset.first)
1738 ConstantOffsetPtrs[&I] = BaseAndOffset;
1739 }
1740
1741 // This is really weird. Technically, ptrtoint will disable SROA. However,
1742 // unless that ptrtoint is *used* somewhere in the live basic blocks after
1743 // inlining, it will be nuked, and SROA should proceed. All of the uses which
1744 // would block SROA would also block SROA if applied directly to a pointer,
1745 // and so we can just add the integer in here. The only places where SROA is
1746 // preserved either cannot fire on an integer, or won't in-and-of themselves
1747 // disable SROA (ext) w/o some later use that we would see and disable.
1748 if (auto *SROAArg = getSROAArgForValueOrNull(V: I.getOperand(i_nocapture: 0)))
1749 SROAArgValues[&I] = SROAArg;
1750
1751 return TTI.getInstructionCost(U: &I, CostKind: TargetTransformInfo::TCK_SizeAndLatency) ==
1752 TargetTransformInfo::TCC_Free;
1753}
1754
1755bool CallAnalyzer::visitIntToPtr(IntToPtrInst &I) {
1756 // Propagate constants through ptrtoint.
1757 if (simplifyInstruction(I))
1758 return true;
1759
1760 // Track base/offset pairs when round-tripped through a pointer without
1761 // modifications provided the integer is not too large.
1762 Value *Op = I.getOperand(i_nocapture: 0);
1763 unsigned IntegerSize = Op->getType()->getScalarSizeInBits();
1764 if (IntegerSize <= DL.getPointerTypeSizeInBits(I.getType())) {
1765 std::pair<Value *, APInt> BaseAndOffset = ConstantOffsetPtrs.lookup(Val: Op);
1766 if (BaseAndOffset.first)
1767 ConstantOffsetPtrs[&I] = BaseAndOffset;
1768 }
1769
1770 // "Propagate" SROA here in the same manner as we do for ptrtoint above.
1771 if (auto *SROAArg = getSROAArgForValueOrNull(V: Op))
1772 SROAArgValues[&I] = SROAArg;
1773
1774 return TTI.getInstructionCost(U: &I, CostKind: TargetTransformInfo::TCK_SizeAndLatency) ==
1775 TargetTransformInfo::TCC_Free;
1776}
1777
1778bool CallAnalyzer::visitCastInst(CastInst &I) {
1779 // Propagate constants through casts.
1780 if (simplifyInstruction(I))
1781 return true;
1782
1783 // Disable SROA in the face of arbitrary casts we don't explicitly list
1784 // elsewhere.
1785 disableSROA(V: I.getOperand(i_nocapture: 0));
1786
1787 // If this is a floating-point cast, and the target says this operation
1788 // is expensive, this may eventually become a library call. Treat the cost
1789 // as such.
1790 switch (I.getOpcode()) {
1791 case Instruction::FPTrunc:
1792 case Instruction::FPExt:
1793 case Instruction::UIToFP:
1794 case Instruction::SIToFP:
1795 case Instruction::FPToUI:
1796 case Instruction::FPToSI:
1797 if (TTI.getFPOpCost(Ty: I.getType()) == TargetTransformInfo::TCC_Expensive)
1798 onCallPenalty();
1799 break;
1800 default:
1801 break;
1802 }
1803
1804 return TTI.getInstructionCost(U: &I, CostKind: TargetTransformInfo::TCK_SizeAndLatency) ==
1805 TargetTransformInfo::TCC_Free;
1806}
1807
1808bool CallAnalyzer::paramHasAttr(Argument *A, Attribute::AttrKind Attr) {
1809 return CandidateCall.paramHasAttr(ArgNo: A->getArgNo(), Kind: Attr);
1810}
1811
1812bool CallAnalyzer::isKnownNonNullInCallee(Value *V) {
1813 // Does the *call site* have the NonNull attribute set on an argument? We
1814 // use the attribute on the call site to memoize any analysis done in the
1815 // caller. This will also trip if the callee function has a non-null
1816 // parameter attribute, but that's a less interesting case because hopefully
1817 // the callee would already have been simplified based on that.
1818 if (Argument *A = dyn_cast<Argument>(Val: V))
1819 if (paramHasAttr(A, Attr: Attribute::NonNull))
1820 return true;
1821
1822 // Is this an alloca in the caller? This is distinct from the attribute case
1823 // above because attributes aren't updated within the inliner itself and we
1824 // always want to catch the alloca derived case.
1825 if (isAllocaDerivedArg(V))
1826 // We can actually predict the result of comparisons between an
1827 // alloca-derived value and null. Note that this fires regardless of
1828 // SROA firing.
1829 return true;
1830
1831 return false;
1832}
1833
1834bool CallAnalyzer::allowSizeGrowth(CallBase &Call) {
1835 // If the normal destination of the invoke or the parent block of the call
1836 // site is unreachable-terminated, there is little point in inlining this
1837 // unless there is literally zero cost.
1838 // FIXME: Note that it is possible that an unreachable-terminated block has a
1839 // hot entry. For example, in below scenario inlining hot_call_X() may be
1840 // beneficial :
1841 // main() {
1842 // hot_call_1();
1843 // ...
1844 // hot_call_N()
1845 // exit(0);
1846 // }
1847 // For now, we are not handling this corner case here as it is rare in real
1848 // code. In future, we should elaborate this based on BPI and BFI in more
1849 // general threshold adjusting heuristics in updateThreshold().
1850 if (InvokeInst *II = dyn_cast<InvokeInst>(Val: &Call)) {
1851 if (isa<UnreachableInst>(Val: II->getNormalDest()->getTerminator()))
1852 return false;
1853 } else if (isa<UnreachableInst>(Val: Call.getParent()->getTerminator()))
1854 return false;
1855
1856 return true;
1857}
1858
1859bool InlineCostCallAnalyzer::isColdCallSite(CallBase &Call,
1860 BlockFrequencyInfo *CallerBFI) {
1861 // If global profile summary is available, then callsite's coldness is
1862 // determined based on that.
1863 if (PSI && PSI->hasProfileSummary())
1864 return PSI->isColdCallSite(CB: Call, BFI: CallerBFI);
1865
1866 // Otherwise we need BFI to be available.
1867 if (!CallerBFI)
1868 return false;
1869
1870 // Determine if the callsite is cold relative to caller's entry. We could
1871 // potentially cache the computation of scaled entry frequency, but the added
1872 // complexity is not worth it unless this scaling shows up high in the
1873 // profiles.
1874 const BranchProbability ColdProb(ColdCallSiteRelFreq, 100);
1875 auto CallSiteBB = Call.getParent();
1876 auto CallSiteFreq = CallerBFI->getBlockFreq(BB: CallSiteBB);
1877 auto CallerEntryFreq =
1878 CallerBFI->getBlockFreq(BB: &(Call.getCaller()->getEntryBlock()));
1879 return CallSiteFreq < CallerEntryFreq * ColdProb;
1880}
1881
1882std::optional<int>
1883InlineCostCallAnalyzer::getHotCallSiteThreshold(CallBase &Call,
1884 BlockFrequencyInfo *CallerBFI) {
1885
1886 // If global profile summary is available, then callsite's hotness is
1887 // determined based on that.
1888 if (PSI && PSI->hasProfileSummary() && PSI->isHotCallSite(CB: Call, BFI: CallerBFI))
1889 return Params.HotCallSiteThreshold;
1890
1891 // Otherwise we need BFI to be available and to have a locally hot callsite
1892 // threshold.
1893 if (!CallerBFI || !Params.LocallyHotCallSiteThreshold)
1894 return std::nullopt;
1895
1896 // Determine if the callsite is hot relative to caller's entry. We could
1897 // potentially cache the computation of scaled entry frequency, but the added
1898 // complexity is not worth it unless this scaling shows up high in the
1899 // profiles.
1900 const BasicBlock *CallSiteBB = Call.getParent();
1901 BlockFrequency CallSiteFreq = CallerBFI->getBlockFreq(BB: CallSiteBB);
1902 BlockFrequency CallerEntryFreq = CallerBFI->getEntryFreq();
1903 std::optional<BlockFrequency> Limit = CallerEntryFreq.mul(Factor: HotCallSiteRelFreq);
1904 if (Limit && CallSiteFreq >= *Limit)
1905 return Params.LocallyHotCallSiteThreshold;
1906
1907 // Otherwise treat it normally.
1908 return std::nullopt;
1909}
1910
1911void InlineCostCallAnalyzer::updateThreshold(CallBase &Call, Function &Callee) {
1912 // If no size growth is allowed for this inlining, set Threshold to 0.
1913 if (!allowSizeGrowth(Call)) {
1914 Threshold = 0;
1915 return;
1916 }
1917
1918 Function *Caller = Call.getCaller();
1919
1920 // return min(A, B) if B is valid.
1921 auto MinIfValid = [](int A, std::optional<int> B) {
1922 return B ? std::min(a: A, b: *B) : A;
1923 };
1924
1925 // return max(A, B) if B is valid.
1926 auto MaxIfValid = [](int A, std::optional<int> B) {
1927 return B ? std::max(a: A, b: *B) : A;
1928 };
1929
1930 // Various bonus percentages. These are multiplied by Threshold to get the
1931 // bonus values.
1932 // SingleBBBonus: This bonus is applied if the callee has a single reachable
1933 // basic block at the given callsite context. This is speculatively applied
1934 // and withdrawn if more than one basic block is seen.
1935 //
1936 // LstCallToStaticBonus: This large bonus is applied to ensure the inlining
1937 // of the last call to a static function as inlining such functions is
1938 // guaranteed to reduce code size.
1939 //
1940 // These bonus percentages may be set to 0 based on properties of the caller
1941 // and the callsite.
1942 int SingleBBBonusPercent = 50;
1943 int VectorBonusPercent = TTI.getInlinerVectorBonusPercent();
1944 int LastCallToStaticBonus = InlineConstants::LastCallToStaticBonus;
1945
1946 // Lambda to set all the above bonus and bonus percentages to 0.
1947 auto DisallowAllBonuses = [&]() {
1948 SingleBBBonusPercent = 0;
1949 VectorBonusPercent = 0;
1950 LastCallToStaticBonus = 0;
1951 };
1952
1953 // Use the OptMinSizeThreshold or OptSizeThreshold knob if they are available
1954 // and reduce the threshold if the caller has the necessary attribute.
1955 if (Caller->hasMinSize()) {
1956 Threshold = MinIfValid(Threshold, Params.OptMinSizeThreshold);
1957 // For minsize, we want to disable the single BB bonus and the vector
1958 // bonuses, but not the last-call-to-static bonus. Inlining the last call to
1959 // a static function will, at the minimum, eliminate the parameter setup and
1960 // call/return instructions.
1961 SingleBBBonusPercent = 0;
1962 VectorBonusPercent = 0;
1963 } else if (Caller->hasOptSize())
1964 Threshold = MinIfValid(Threshold, Params.OptSizeThreshold);
1965
1966 // Adjust the threshold based on inlinehint attribute and profile based
1967 // hotness information if the caller does not have MinSize attribute.
1968 if (!Caller->hasMinSize()) {
1969 if (Callee.hasFnAttribute(Kind: Attribute::InlineHint))
1970 Threshold = MaxIfValid(Threshold, Params.HintThreshold);
1971
1972 // FIXME: After switching to the new passmanager, simplify the logic below
1973 // by checking only the callsite hotness/coldness as we will reliably
1974 // have local profile information.
1975 //
1976 // Callsite hotness and coldness can be determined if sample profile is
1977 // used (which adds hotness metadata to calls) or if caller's
1978 // BlockFrequencyInfo is available.
1979 BlockFrequencyInfo *CallerBFI = GetBFI ? &(GetBFI(*Caller)) : nullptr;
1980 auto HotCallSiteThreshold = getHotCallSiteThreshold(Call, CallerBFI);
1981 if (!Caller->hasOptSize() && HotCallSiteThreshold) {
1982 LLVM_DEBUG(dbgs() << "Hot callsite.\n");
1983 // FIXME: This should update the threshold only if it exceeds the
1984 // current threshold, but AutoFDO + ThinLTO currently relies on this
1985 // behavior to prevent inlining of hot callsites during ThinLTO
1986 // compile phase.
1987 Threshold = *HotCallSiteThreshold;
1988 } else if (isColdCallSite(Call, CallerBFI)) {
1989 LLVM_DEBUG(dbgs() << "Cold callsite.\n");
1990 // Do not apply bonuses for a cold callsite including the
1991 // LastCallToStatic bonus. While this bonus might result in code size
1992 // reduction, it can cause the size of a non-cold caller to increase
1993 // preventing it from being inlined.
1994 DisallowAllBonuses();
1995 Threshold = MinIfValid(Threshold, Params.ColdCallSiteThreshold);
1996 } else if (PSI) {
1997 // Use callee's global profile information only if we have no way of
1998 // determining this via callsite information.
1999 if (PSI->isFunctionEntryHot(F: &Callee)) {
2000 LLVM_DEBUG(dbgs() << "Hot callee.\n");
2001 // If callsite hotness can not be determined, we may still know
2002 // that the callee is hot and treat it as a weaker hint for threshold
2003 // increase.
2004 Threshold = MaxIfValid(Threshold, Params.HintThreshold);
2005 } else if (PSI->isFunctionEntryCold(F: &Callee)) {
2006 LLVM_DEBUG(dbgs() << "Cold callee.\n");
2007 // Do not apply bonuses for a cold callee including the
2008 // LastCallToStatic bonus. While this bonus might result in code size
2009 // reduction, it can cause the size of a non-cold caller to increase
2010 // preventing it from being inlined.
2011 DisallowAllBonuses();
2012 Threshold = MinIfValid(Threshold, Params.ColdThreshold);
2013 }
2014 }
2015 }
2016
2017 Threshold += TTI.adjustInliningThreshold(CB: &Call);
2018
2019 // Finally, take the target-specific inlining threshold multiplier into
2020 // account.
2021 Threshold *= TTI.getInliningThresholdMultiplier();
2022
2023 SingleBBBonus = Threshold * SingleBBBonusPercent / 100;
2024 VectorBonus = Threshold * VectorBonusPercent / 100;
2025
2026 // If there is only one call of the function, and it has internal linkage,
2027 // the cost of inlining it drops dramatically. It may seem odd to update
2028 // Cost in updateThreshold, but the bonus depends on the logic in this method.
2029 if (isSoleCallToLocalFunction(CB: Call, Callee: F)) {
2030 Cost -= LastCallToStaticBonus;
2031 StaticBonusApplied = LastCallToStaticBonus;
2032 }
2033}
2034
2035bool CallAnalyzer::visitCmpInst(CmpInst &I) {
2036 Value *LHS = I.getOperand(i_nocapture: 0), *RHS = I.getOperand(i_nocapture: 1);
2037 // First try to handle simplified comparisons.
2038 if (simplifyInstruction(I))
2039 return true;
2040
2041 if (I.getOpcode() == Instruction::FCmp)
2042 return false;
2043
2044 // Otherwise look for a comparison between constant offset pointers with
2045 // a common base.
2046 Value *LHSBase, *RHSBase;
2047 APInt LHSOffset, RHSOffset;
2048 std::tie(args&: LHSBase, args&: LHSOffset) = ConstantOffsetPtrs.lookup(Val: LHS);
2049 if (LHSBase) {
2050 std::tie(args&: RHSBase, args&: RHSOffset) = ConstantOffsetPtrs.lookup(Val: RHS);
2051 if (RHSBase && LHSBase == RHSBase) {
2052 // We have common bases, fold the icmp to a constant based on the
2053 // offsets.
2054 SimplifiedValues[&I] = ConstantInt::getBool(
2055 Ty: I.getType(),
2056 V: ICmpInst::compare(LHS: LHSOffset, RHS: RHSOffset, Pred: I.getPredicate()));
2057 ++NumConstantPtrCmps;
2058 return true;
2059 }
2060 }
2061
2062 auto isImplicitNullCheckCmp = [](const CmpInst &I) {
2063 for (auto *User : I.users())
2064 if (auto *Instr = dyn_cast<Instruction>(Val: User))
2065 if (!Instr->getMetadata(KindID: LLVMContext::MD_make_implicit))
2066 return false;
2067 return true;
2068 };
2069
2070 // If the comparison is an equality comparison with null, we can simplify it
2071 // if we know the value (argument) can't be null
2072 if (I.isEquality() && isa<ConstantPointerNull>(Val: I.getOperand(i_nocapture: 1))) {
2073 if (isKnownNonNullInCallee(V: I.getOperand(i_nocapture: 0))) {
2074 bool IsNotEqual = I.getPredicate() == CmpInst::ICMP_NE;
2075 SimplifiedValues[&I] = IsNotEqual ? ConstantInt::getTrue(Ty: I.getType())
2076 : ConstantInt::getFalse(Ty: I.getType());
2077 return true;
2078 }
2079 // Implicit null checks act as unconditional branches and their comparisons
2080 // should be treated as simplified and free of cost.
2081 if (isImplicitNullCheckCmp(I))
2082 return true;
2083 }
2084 return handleSROA(V: I.getOperand(i_nocapture: 0), DoNotDisable: isa<ConstantPointerNull>(Val: I.getOperand(i_nocapture: 1)));
2085}
2086
2087bool CallAnalyzer::visitSub(BinaryOperator &I) {
2088 // Try to handle a special case: we can fold computing the difference of two
2089 // constant-related pointers.
2090 Value *LHS = I.getOperand(i_nocapture: 0), *RHS = I.getOperand(i_nocapture: 1);
2091 Value *LHSBase, *RHSBase;
2092 APInt LHSOffset, RHSOffset;
2093 std::tie(args&: LHSBase, args&: LHSOffset) = ConstantOffsetPtrs.lookup(Val: LHS);
2094 if (LHSBase) {
2095 std::tie(args&: RHSBase, args&: RHSOffset) = ConstantOffsetPtrs.lookup(Val: RHS);
2096 if (RHSBase && LHSBase == RHSBase) {
2097 // We have common bases, fold the subtract to a constant based on the
2098 // offsets.
2099 Constant *CLHS = ConstantInt::get(Context&: LHS->getContext(), V: LHSOffset);
2100 Constant *CRHS = ConstantInt::get(Context&: RHS->getContext(), V: RHSOffset);
2101 if (Constant *C = ConstantExpr::getSub(C1: CLHS, C2: CRHS)) {
2102 SimplifiedValues[&I] = C;
2103 ++NumConstantPtrDiffs;
2104 return true;
2105 }
2106 }
2107 }
2108
2109 // Otherwise, fall back to the generic logic for simplifying and handling
2110 // instructions.
2111 return Base::visitSub(I);
2112}
2113
2114bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) {
2115 Value *LHS = I.getOperand(i_nocapture: 0), *RHS = I.getOperand(i_nocapture: 1);
2116 Constant *CLHS = dyn_cast<Constant>(Val: LHS);
2117 if (!CLHS)
2118 CLHS = SimplifiedValues.lookup(Val: LHS);
2119 Constant *CRHS = dyn_cast<Constant>(Val: RHS);
2120 if (!CRHS)
2121 CRHS = SimplifiedValues.lookup(Val: RHS);
2122
2123 Value *SimpleV = nullptr;
2124 if (auto FI = dyn_cast<FPMathOperator>(Val: &I))
2125 SimpleV = simplifyBinOp(Opcode: I.getOpcode(), LHS: CLHS ? CLHS : LHS, RHS: CRHS ? CRHS : RHS,
2126 FMF: FI->getFastMathFlags(), Q: DL);
2127 else
2128 SimpleV =
2129 simplifyBinOp(Opcode: I.getOpcode(), LHS: CLHS ? CLHS : LHS, RHS: CRHS ? CRHS : RHS, Q: DL);
2130
2131 if (Constant *C = dyn_cast_or_null<Constant>(Val: SimpleV))
2132 SimplifiedValues[&I] = C;
2133
2134 if (SimpleV)
2135 return true;
2136
2137 // Disable any SROA on arguments to arbitrary, unsimplified binary operators.
2138 disableSROA(V: LHS);
2139 disableSROA(V: RHS);
2140
2141 // If the instruction is floating point, and the target says this operation
2142 // is expensive, this may eventually become a library call. Treat the cost
2143 // as such. Unless it's fneg which can be implemented with an xor.
2144 using namespace llvm::PatternMatch;
2145 if (I.getType()->isFloatingPointTy() &&
2146 TTI.getFPOpCost(Ty: I.getType()) == TargetTransformInfo::TCC_Expensive &&
2147 !match(V: &I, P: m_FNeg(X: m_Value())))
2148 onCallPenalty();
2149
2150 return false;
2151}
2152
2153bool CallAnalyzer::visitFNeg(UnaryOperator &I) {
2154 Value *Op = I.getOperand(i_nocapture: 0);
2155 Constant *COp = dyn_cast<Constant>(Val: Op);
2156 if (!COp)
2157 COp = SimplifiedValues.lookup(Val: Op);
2158
2159 Value *SimpleV = simplifyFNegInst(
2160 Op: COp ? COp : Op, FMF: cast<FPMathOperator>(Val&: I).getFastMathFlags(), Q: DL);
2161
2162 if (Constant *C = dyn_cast_or_null<Constant>(Val: SimpleV))
2163 SimplifiedValues[&I] = C;
2164
2165 if (SimpleV)
2166 return true;
2167
2168 // Disable any SROA on arguments to arbitrary, unsimplified fneg.
2169 disableSROA(V: Op);
2170
2171 return false;
2172}
2173
2174bool CallAnalyzer::visitLoad(LoadInst &I) {
2175 if (handleSROA(V: I.getPointerOperand(), DoNotDisable: I.isSimple()))
2176 return true;
2177
2178 // If the data is already loaded from this address and hasn't been clobbered
2179 // by any stores or calls, this load is likely to be redundant and can be
2180 // eliminated.
2181 if (EnableLoadElimination &&
2182 !LoadAddrSet.insert(Ptr: I.getPointerOperand()).second && I.isUnordered()) {
2183 onLoadEliminationOpportunity();
2184 return true;
2185 }
2186
2187 onMemAccess();
2188 return false;
2189}
2190
2191bool CallAnalyzer::visitStore(StoreInst &I) {
2192 if (handleSROA(V: I.getPointerOperand(), DoNotDisable: I.isSimple()))
2193 return true;
2194
2195 // The store can potentially clobber loads and prevent repeated loads from
2196 // being eliminated.
2197 // FIXME:
2198 // 1. We can probably keep an initial set of eliminatable loads substracted
2199 // from the cost even when we finally see a store. We just need to disable
2200 // *further* accumulation of elimination savings.
2201 // 2. We should probably at some point thread MemorySSA for the callee into
2202 // this and then use that to actually compute *really* precise savings.
2203 disableLoadElimination();
2204
2205 onMemAccess();
2206 return false;
2207}
2208
2209bool CallAnalyzer::visitExtractValue(ExtractValueInst &I) {
2210 // Constant folding for extract value is trivial.
2211 if (simplifyInstruction(I))
2212 return true;
2213
2214 // SROA can't look through these, but they may be free.
2215 return Base::visitExtractValue(I);
2216}
2217
2218bool CallAnalyzer::visitInsertValue(InsertValueInst &I) {
2219 // Constant folding for insert value is trivial.
2220 if (simplifyInstruction(I))
2221 return true;
2222
2223 // SROA can't look through these, but they may be free.
2224 return Base::visitInsertValue(I);
2225}
2226
2227/// Try to simplify a call site.
2228///
2229/// Takes a concrete function and callsite and tries to actually simplify it by
2230/// analyzing the arguments and call itself with instsimplify. Returns true if
2231/// it has simplified the callsite to some other entity (a constant), making it
2232/// free.
2233bool CallAnalyzer::simplifyCallSite(Function *F, CallBase &Call) {
2234 // FIXME: Using the instsimplify logic directly for this is inefficient
2235 // because we have to continually rebuild the argument list even when no
2236 // simplifications can be performed. Until that is fixed with remapping
2237 // inside of instsimplify, directly constant fold calls here.
2238 if (!canConstantFoldCallTo(Call: &Call, F))
2239 return false;
2240
2241 // Try to re-map the arguments to constants.
2242 SmallVector<Constant *, 4> ConstantArgs;
2243 ConstantArgs.reserve(N: Call.arg_size());
2244 for (Value *I : Call.args()) {
2245 Constant *C = dyn_cast<Constant>(Val: I);
2246 if (!C)
2247 C = dyn_cast_or_null<Constant>(Val: SimplifiedValues.lookup(Val: I));
2248 if (!C)
2249 return false; // This argument doesn't map to a constant.
2250
2251 ConstantArgs.push_back(Elt: C);
2252 }
2253 if (Constant *C = ConstantFoldCall(Call: &Call, F, Operands: ConstantArgs)) {
2254 SimplifiedValues[&Call] = C;
2255 return true;
2256 }
2257
2258 return false;
2259}
2260
2261bool CallAnalyzer::visitCallBase(CallBase &Call) {
2262 if (!onCallBaseVisitStart(Call))
2263 return true;
2264
2265 if (Call.hasFnAttr(Kind: Attribute::ReturnsTwice) &&
2266 !F.hasFnAttribute(Kind: Attribute::ReturnsTwice)) {
2267 // This aborts the entire analysis.
2268 ExposesReturnsTwice = true;
2269 return false;
2270 }
2271 if (isa<CallInst>(Val: Call) && cast<CallInst>(Val&: Call).cannotDuplicate())
2272 ContainsNoDuplicateCall = true;
2273
2274 Function *F = Call.getCalledFunction();
2275 bool IsIndirectCall = !F;
2276 if (IsIndirectCall) {
2277 // Check if this happens to be an indirect function call to a known function
2278 // in this inline context. If not, we've done all we can.
2279 Value *Callee = Call.getCalledOperand();
2280 F = dyn_cast_or_null<Function>(Val: SimplifiedValues.lookup(Val: Callee));
2281 if (!F || F->getFunctionType() != Call.getFunctionType()) {
2282 onCallArgumentSetup(Call);
2283
2284 if (!Call.onlyReadsMemory())
2285 disableLoadElimination();
2286 return Base::visitCallBase(I&: Call);
2287 }
2288 }
2289
2290 assert(F && "Expected a call to a known function");
2291
2292 // When we have a concrete function, first try to simplify it directly.
2293 if (simplifyCallSite(F, Call))
2294 return true;
2295
2296 // Next check if it is an intrinsic we know about.
2297 // FIXME: Lift this into part of the InstVisitor.
2298 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Val: &Call)) {
2299 switch (II->getIntrinsicID()) {
2300 default:
2301 if (!Call.onlyReadsMemory() && !isAssumeLikeIntrinsic(I: II))
2302 disableLoadElimination();
2303 return Base::visitCallBase(I&: Call);
2304
2305 case Intrinsic::load_relative:
2306 onLoadRelativeIntrinsic();
2307 return false;
2308
2309 case Intrinsic::memset:
2310 case Intrinsic::memcpy:
2311 case Intrinsic::memmove:
2312 disableLoadElimination();
2313 // SROA can usually chew through these intrinsics, but they aren't free.
2314 return false;
2315 case Intrinsic::icall_branch_funnel:
2316 case Intrinsic::localescape:
2317 HasUninlineableIntrinsic = true;
2318 return false;
2319 case Intrinsic::vastart:
2320 InitsVargArgs = true;
2321 return false;
2322 case Intrinsic::launder_invariant_group:
2323 case Intrinsic::strip_invariant_group:
2324 if (auto *SROAArg = getSROAArgForValueOrNull(V: II->getOperand(i_nocapture: 0)))
2325 SROAArgValues[II] = SROAArg;
2326 return true;
2327 case Intrinsic::is_constant:
2328 return simplifyIntrinsicCallIsConstant(CB&: Call);
2329 case Intrinsic::objectsize:
2330 return simplifyIntrinsicCallObjectSize(CB&: Call);
2331 }
2332 }
2333
2334 if (F == Call.getFunction()) {
2335 // This flag will fully abort the analysis, so don't bother with anything
2336 // else.
2337 IsRecursiveCall = true;
2338 if (!AllowRecursiveCall)
2339 return false;
2340 }
2341
2342 if (TTI.isLoweredToCall(F)) {
2343 onLoweredCall(F, Call, IsIndirectCall);
2344 }
2345
2346 if (!(Call.onlyReadsMemory() || (IsIndirectCall && F->onlyReadsMemory())))
2347 disableLoadElimination();
2348 return Base::visitCallBase(I&: Call);
2349}
2350
2351bool CallAnalyzer::visitReturnInst(ReturnInst &RI) {
2352 // At least one return instruction will be free after inlining.
2353 bool Free = !HasReturn;
2354 HasReturn = true;
2355 return Free;
2356}
2357
2358bool CallAnalyzer::visitBranchInst(BranchInst &BI) {
2359 // We model unconditional branches as essentially free -- they really
2360 // shouldn't exist at all, but handling them makes the behavior of the
2361 // inliner more regular and predictable. Interestingly, conditional branches
2362 // which will fold away are also free.
2363 return BI.isUnconditional() || isa<ConstantInt>(Val: BI.getCondition()) ||
2364 BI.getMetadata(KindID: LLVMContext::MD_make_implicit) ||
2365 isa_and_nonnull<ConstantInt>(
2366 Val: SimplifiedValues.lookup(Val: BI.getCondition()));
2367}
2368
2369bool CallAnalyzer::visitSelectInst(SelectInst &SI) {
2370 bool CheckSROA = SI.getType()->isPointerTy();
2371 Value *TrueVal = SI.getTrueValue();
2372 Value *FalseVal = SI.getFalseValue();
2373
2374 Constant *TrueC = dyn_cast<Constant>(Val: TrueVal);
2375 if (!TrueC)
2376 TrueC = SimplifiedValues.lookup(Val: TrueVal);
2377 Constant *FalseC = dyn_cast<Constant>(Val: FalseVal);
2378 if (!FalseC)
2379 FalseC = SimplifiedValues.lookup(Val: FalseVal);
2380 Constant *CondC =
2381 dyn_cast_or_null<Constant>(Val: SimplifiedValues.lookup(Val: SI.getCondition()));
2382
2383 if (!CondC) {
2384 // Select C, X, X => X
2385 if (TrueC == FalseC && TrueC) {
2386 SimplifiedValues[&SI] = TrueC;
2387 return true;
2388 }
2389
2390 if (!CheckSROA)
2391 return Base::visitSelectInst(I&: SI);
2392
2393 std::pair<Value *, APInt> TrueBaseAndOffset =
2394 ConstantOffsetPtrs.lookup(Val: TrueVal);
2395 std::pair<Value *, APInt> FalseBaseAndOffset =
2396 ConstantOffsetPtrs.lookup(Val: FalseVal);
2397 if (TrueBaseAndOffset == FalseBaseAndOffset && TrueBaseAndOffset.first) {
2398 ConstantOffsetPtrs[&SI] = TrueBaseAndOffset;
2399
2400 if (auto *SROAArg = getSROAArgForValueOrNull(V: TrueVal))
2401 SROAArgValues[&SI] = SROAArg;
2402 return true;
2403 }
2404
2405 return Base::visitSelectInst(I&: SI);
2406 }
2407
2408 // Select condition is a constant.
2409 Value *SelectedV = CondC->isAllOnesValue() ? TrueVal
2410 : (CondC->isNullValue()) ? FalseVal
2411 : nullptr;
2412 if (!SelectedV) {
2413 // Condition is a vector constant that is not all 1s or all 0s. If all
2414 // operands are constants, ConstantFoldSelectInstruction() can handle the
2415 // cases such as select vectors.
2416 if (TrueC && FalseC) {
2417 if (auto *C = ConstantFoldSelectInstruction(Cond: CondC, V1: TrueC, V2: FalseC)) {
2418 SimplifiedValues[&SI] = C;
2419 return true;
2420 }
2421 }
2422 return Base::visitSelectInst(I&: SI);
2423 }
2424
2425 // Condition is either all 1s or all 0s. SI can be simplified.
2426 if (Constant *SelectedC = dyn_cast<Constant>(Val: SelectedV)) {
2427 SimplifiedValues[&SI] = SelectedC;
2428 return true;
2429 }
2430
2431 if (!CheckSROA)
2432 return true;
2433
2434 std::pair<Value *, APInt> BaseAndOffset =
2435 ConstantOffsetPtrs.lookup(Val: SelectedV);
2436 if (BaseAndOffset.first) {
2437 ConstantOffsetPtrs[&SI] = BaseAndOffset;
2438
2439 if (auto *SROAArg = getSROAArgForValueOrNull(V: SelectedV))
2440 SROAArgValues[&SI] = SROAArg;
2441 }
2442
2443 return true;
2444}
2445
2446bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) {
2447 // We model unconditional switches as free, see the comments on handling
2448 // branches.
2449 if (isa<ConstantInt>(Val: SI.getCondition()))
2450 return true;
2451 if (Value *V = SimplifiedValues.lookup(Val: SI.getCondition()))
2452 if (isa<ConstantInt>(Val: V))
2453 return true;
2454
2455 // Assume the most general case where the switch is lowered into
2456 // either a jump table, bit test, or a balanced binary tree consisting of
2457 // case clusters without merging adjacent clusters with the same
2458 // destination. We do not consider the switches that are lowered with a mix
2459 // of jump table/bit test/binary search tree. The cost of the switch is
2460 // proportional to the size of the tree or the size of jump table range.
2461 //
2462 // NB: We convert large switches which are just used to initialize large phi
2463 // nodes to lookup tables instead in simplifycfg, so this shouldn't prevent
2464 // inlining those. It will prevent inlining in cases where the optimization
2465 // does not (yet) fire.
2466
2467 unsigned JumpTableSize = 0;
2468 BlockFrequencyInfo *BFI = GetBFI ? &(GetBFI(F)) : nullptr;
2469 unsigned NumCaseCluster =
2470 TTI.getEstimatedNumberOfCaseClusters(SI, JTSize&: JumpTableSize, PSI, BFI);
2471
2472 onFinalizeSwitch(JumpTableSize, NumCaseCluster, DefaultDestUndefined: SI.defaultDestUndefined());
2473 return false;
2474}
2475
2476bool CallAnalyzer::visitIndirectBrInst(IndirectBrInst &IBI) {
2477 // We never want to inline functions that contain an indirectbr. This is
2478 // incorrect because all the blockaddress's (in static global initializers
2479 // for example) would be referring to the original function, and this
2480 // indirect jump would jump from the inlined copy of the function into the
2481 // original function which is extremely undefined behavior.
2482 // FIXME: This logic isn't really right; we can safely inline functions with
2483 // indirectbr's as long as no other function or global references the
2484 // blockaddress of a block within the current function.
2485 HasIndirectBr = true;
2486 return false;
2487}
2488
2489bool CallAnalyzer::visitResumeInst(ResumeInst &RI) {
2490 // FIXME: It's not clear that a single instruction is an accurate model for
2491 // the inline cost of a resume instruction.
2492 return false;
2493}
2494
2495bool CallAnalyzer::visitCleanupReturnInst(CleanupReturnInst &CRI) {
2496 // FIXME: It's not clear that a single instruction is an accurate model for
2497 // the inline cost of a cleanupret instruction.
2498 return false;
2499}
2500
2501bool CallAnalyzer::visitCatchReturnInst(CatchReturnInst &CRI) {
2502 // FIXME: It's not clear that a single instruction is an accurate model for
2503 // the inline cost of a catchret instruction.
2504 return false;
2505}
2506
2507bool CallAnalyzer::visitUnreachableInst(UnreachableInst &I) {
2508 // FIXME: It might be reasonably to discount the cost of instructions leading
2509 // to unreachable as they have the lowest possible impact on both runtime and
2510 // code size.
2511 return true; // No actual code is needed for unreachable.
2512}
2513
2514bool CallAnalyzer::visitInstruction(Instruction &I) {
2515 // Some instructions are free. All of the free intrinsics can also be
2516 // handled by SROA, etc.
2517 if (TTI.getInstructionCost(U: &I, CostKind: TargetTransformInfo::TCK_SizeAndLatency) ==
2518 TargetTransformInfo::TCC_Free)
2519 return true;
2520
2521 // We found something we don't understand or can't handle. Mark any SROA-able
2522 // values in the operand list as no longer viable.
2523 for (const Use &Op : I.operands())
2524 disableSROA(V: Op);
2525
2526 return false;
2527}
2528
2529/// Analyze a basic block for its contribution to the inline cost.
2530///
2531/// This method walks the analyzer over every instruction in the given basic
2532/// block and accounts for their cost during inlining at this callsite. It
2533/// aborts early if the threshold has been exceeded or an impossible to inline
2534/// construct has been detected. It returns false if inlining is no longer
2535/// viable, and true if inlining remains viable.
2536InlineResult
2537CallAnalyzer::analyzeBlock(BasicBlock *BB,
2538 SmallPtrSetImpl<const Value *> &EphValues) {
2539 for (Instruction &I : *BB) {
2540 // FIXME: Currently, the number of instructions in a function regardless of
2541 // our ability to simplify them during inline to constants or dead code,
2542 // are actually used by the vector bonus heuristic. As long as that's true,
2543 // we have to special case debug intrinsics here to prevent differences in
2544 // inlining due to debug symbols. Eventually, the number of unsimplified
2545 // instructions shouldn't factor into the cost computation, but until then,
2546 // hack around it here.
2547 // Similarly, skip pseudo-probes.
2548 if (I.isDebugOrPseudoInst())
2549 continue;
2550
2551 // Skip ephemeral values.
2552 if (EphValues.count(Ptr: &I))
2553 continue;
2554
2555 ++NumInstructions;
2556 if (isa<ExtractElementInst>(Val: I) || I.getType()->isVectorTy())
2557 ++NumVectorInstructions;
2558
2559 // If the instruction simplified to a constant, there is no cost to this
2560 // instruction. Visit the instructions using our InstVisitor to account for
2561 // all of the per-instruction logic. The visit tree returns true if we
2562 // consumed the instruction in any way, and false if the instruction's base
2563 // cost should count against inlining.
2564 onInstructionAnalysisStart(I: &I);
2565
2566 if (Base::visit(I: &I))
2567 ++NumInstructionsSimplified;
2568 else
2569 onMissedSimplification();
2570
2571 onInstructionAnalysisFinish(I: &I);
2572 using namespace ore;
2573 // If the visit this instruction detected an uninlinable pattern, abort.
2574 InlineResult IR = InlineResult::success();
2575 if (IsRecursiveCall && !AllowRecursiveCall)
2576 IR = InlineResult::failure(Reason: "recursive");
2577 else if (ExposesReturnsTwice)
2578 IR = InlineResult::failure(Reason: "exposes returns twice");
2579 else if (HasDynamicAlloca)
2580 IR = InlineResult::failure(Reason: "dynamic alloca");
2581 else if (HasIndirectBr)
2582 IR = InlineResult::failure(Reason: "indirect branch");
2583 else if (HasUninlineableIntrinsic)
2584 IR = InlineResult::failure(Reason: "uninlinable intrinsic");
2585 else if (InitsVargArgs)
2586 IR = InlineResult::failure(Reason: "varargs");
2587 if (!IR.isSuccess()) {
2588 if (ORE)
2589 ORE->emit(RemarkBuilder: [&]() {
2590 return OptimizationRemarkMissed(DEBUG_TYPE, "NeverInline",
2591 &CandidateCall)
2592 << NV("Callee", &F) << " has uninlinable pattern ("
2593 << NV("InlineResult", IR.getFailureReason())
2594 << ") and cost is not fully computed";
2595 });
2596 return IR;
2597 }
2598
2599 // If the caller is a recursive function then we don't want to inline
2600 // functions which allocate a lot of stack space because it would increase
2601 // the caller stack usage dramatically.
2602 if (IsCallerRecursive && AllocatedSize > RecurStackSizeThreshold) {
2603 auto IR =
2604 InlineResult::failure(Reason: "recursive and allocates too much stack space");
2605 if (ORE)
2606 ORE->emit(RemarkBuilder: [&]() {
2607 return OptimizationRemarkMissed(DEBUG_TYPE, "NeverInline",
2608 &CandidateCall)
2609 << NV("Callee", &F) << " is "
2610 << NV("InlineResult", IR.getFailureReason())
2611 << ". Cost is not fully computed";
2612 });
2613 return IR;
2614 }
2615
2616 if (shouldStop())
2617 return InlineResult::failure(
2618 Reason: "Call site analysis is not favorable to inlining.");
2619 }
2620
2621 return InlineResult::success();
2622}
2623
2624/// Compute the base pointer and cumulative constant offsets for V.
2625///
2626/// This strips all constant offsets off of V, leaving it the base pointer, and
2627/// accumulates the total constant offset applied in the returned constant. It
2628/// returns 0 if V is not a pointer, and returns the constant '0' if there are
2629/// no constant offsets applied.
2630ConstantInt *CallAnalyzer::stripAndComputeInBoundsConstantOffsets(Value *&V) {
2631 if (!V->getType()->isPointerTy())
2632 return nullptr;
2633
2634 unsigned AS = V->getType()->getPointerAddressSpace();
2635 unsigned IntPtrWidth = DL.getIndexSizeInBits(AS);
2636 APInt Offset = APInt::getZero(numBits: IntPtrWidth);
2637
2638 // Even though we don't look through PHI nodes, we could be called on an
2639 // instruction in an unreachable block, which may be on a cycle.
2640 SmallPtrSet<Value *, 4> Visited;
2641 Visited.insert(Ptr: V);
2642 do {
2643 if (GEPOperator *GEP = dyn_cast<GEPOperator>(Val: V)) {
2644 if (!GEP->isInBounds() || !accumulateGEPOffset(GEP&: *GEP, Offset))
2645 return nullptr;
2646 V = GEP->getPointerOperand();
2647 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(Val: V)) {
2648 if (GA->isInterposable())
2649 break;
2650 V = GA->getAliasee();
2651 } else {
2652 break;
2653 }
2654 assert(V->getType()->isPointerTy() && "Unexpected operand type!");
2655 } while (Visited.insert(Ptr: V).second);
2656
2657 Type *IdxPtrTy = DL.getIndexType(PtrTy: V->getType());
2658 return cast<ConstantInt>(Val: ConstantInt::get(Ty: IdxPtrTy, V: Offset));
2659}
2660
2661/// Find dead blocks due to deleted CFG edges during inlining.
2662///
2663/// If we know the successor of the current block, \p CurrBB, has to be \p
2664/// NextBB, the other successors of \p CurrBB are dead if these successors have
2665/// no live incoming CFG edges. If one block is found to be dead, we can
2666/// continue growing the dead block list by checking the successors of the dead
2667/// blocks to see if all their incoming edges are dead or not.
2668void CallAnalyzer::findDeadBlocks(BasicBlock *CurrBB, BasicBlock *NextBB) {
2669 auto IsEdgeDead = [&](BasicBlock *Pred, BasicBlock *Succ) {
2670 // A CFG edge is dead if the predecessor is dead or the predecessor has a
2671 // known successor which is not the one under exam.
2672 return (DeadBlocks.count(Ptr: Pred) ||
2673 (KnownSuccessors[Pred] && KnownSuccessors[Pred] != Succ));
2674 };
2675
2676 auto IsNewlyDead = [&](BasicBlock *BB) {
2677 // If all the edges to a block are dead, the block is also dead.
2678 return (!DeadBlocks.count(Ptr: BB) &&
2679 llvm::all_of(Range: predecessors(BB),
2680 P: [&](BasicBlock *P) { return IsEdgeDead(P, BB); }));
2681 };
2682
2683 for (BasicBlock *Succ : successors(BB: CurrBB)) {
2684 if (Succ == NextBB || !IsNewlyDead(Succ))
2685 continue;
2686 SmallVector<BasicBlock *, 4> NewDead;
2687 NewDead.push_back(Elt: Succ);
2688 while (!NewDead.empty()) {
2689 BasicBlock *Dead = NewDead.pop_back_val();
2690 if (DeadBlocks.insert(Ptr: Dead).second)
2691 // Continue growing the dead block lists.
2692 for (BasicBlock *S : successors(BB: Dead))
2693 if (IsNewlyDead(S))
2694 NewDead.push_back(Elt: S);
2695 }
2696 }
2697}
2698
2699/// Analyze a call site for potential inlining.
2700///
2701/// Returns true if inlining this call is viable, and false if it is not
2702/// viable. It computes the cost and adjusts the threshold based on numerous
2703/// factors and heuristics. If this method returns false but the computed cost
2704/// is below the computed threshold, then inlining was forcibly disabled by
2705/// some artifact of the routine.
2706InlineResult CallAnalyzer::analyze() {
2707 ++NumCallsAnalyzed;
2708
2709 auto Result = onAnalysisStart();
2710 if (!Result.isSuccess())
2711 return Result;
2712
2713 if (F.empty())
2714 return InlineResult::success();
2715
2716 Function *Caller = CandidateCall.getFunction();
2717 // Check if the caller function is recursive itself.
2718 for (User *U : Caller->users()) {
2719 CallBase *Call = dyn_cast<CallBase>(Val: U);
2720 if (Call && Call->getFunction() == Caller) {
2721 IsCallerRecursive = true;
2722 break;
2723 }
2724 }
2725
2726 // Populate our simplified values by mapping from function arguments to call
2727 // arguments with known important simplifications.
2728 auto CAI = CandidateCall.arg_begin();
2729 for (Argument &FAI : F.args()) {
2730 assert(CAI != CandidateCall.arg_end());
2731 if (Constant *C = dyn_cast<Constant>(Val: CAI))
2732 SimplifiedValues[&FAI] = C;
2733
2734 Value *PtrArg = *CAI;
2735 if (ConstantInt *C = stripAndComputeInBoundsConstantOffsets(V&: PtrArg)) {
2736 ConstantOffsetPtrs[&FAI] = std::make_pair(x&: PtrArg, y: C->getValue());
2737
2738 // We can SROA any pointer arguments derived from alloca instructions.
2739 if (auto *SROAArg = dyn_cast<AllocaInst>(Val: PtrArg)) {
2740 SROAArgValues[&FAI] = SROAArg;
2741 onInitializeSROAArg(Arg: SROAArg);
2742 EnabledSROAAllocas.insert(V: SROAArg);
2743 }
2744 }
2745 ++CAI;
2746 }
2747 NumConstantArgs = SimplifiedValues.size();
2748 NumConstantOffsetPtrArgs = ConstantOffsetPtrs.size();
2749 NumAllocaArgs = SROAArgValues.size();
2750
2751 // FIXME: If a caller has multiple calls to a callee, we end up recomputing
2752 // the ephemeral values multiple times (and they're completely determined by
2753 // the callee, so this is purely duplicate work).
2754 SmallPtrSet<const Value *, 32> EphValues;
2755 CodeMetrics::collectEphemeralValues(L: &F, AC: &GetAssumptionCache(F), EphValues);
2756
2757 // The worklist of live basic blocks in the callee *after* inlining. We avoid
2758 // adding basic blocks of the callee which can be proven to be dead for this
2759 // particular call site in order to get more accurate cost estimates. This
2760 // requires a somewhat heavyweight iteration pattern: we need to walk the
2761 // basic blocks in a breadth-first order as we insert live successors. To
2762 // accomplish this, prioritizing for small iterations because we exit after
2763 // crossing our threshold, we use a small-size optimized SetVector.
2764 typedef SmallSetVector<BasicBlock *, 16> BBSetVector;
2765 BBSetVector BBWorklist;
2766 BBWorklist.insert(X: &F.getEntryBlock());
2767
2768 // Note that we *must not* cache the size, this loop grows the worklist.
2769 for (unsigned Idx = 0; Idx != BBWorklist.size(); ++Idx) {
2770 if (shouldStop())
2771 break;
2772
2773 BasicBlock *BB = BBWorklist[Idx];
2774 if (BB->empty())
2775 continue;
2776
2777 onBlockStart(BB);
2778
2779 // Disallow inlining a blockaddress with uses other than strictly callbr.
2780 // A blockaddress only has defined behavior for an indirect branch in the
2781 // same function, and we do not currently support inlining indirect
2782 // branches. But, the inliner may not see an indirect branch that ends up
2783 // being dead code at a particular call site. If the blockaddress escapes
2784 // the function, e.g., via a global variable, inlining may lead to an
2785 // invalid cross-function reference.
2786 // FIXME: pr/39560: continue relaxing this overt restriction.
2787 if (BB->hasAddressTaken())
2788 for (User *U : BlockAddress::get(BB: &*BB)->users())
2789 if (!isa<CallBrInst>(Val: *U))
2790 return InlineResult::failure(Reason: "blockaddress used outside of callbr");
2791
2792 // Analyze the cost of this block. If we blow through the threshold, this
2793 // returns false, and we can bail on out.
2794 InlineResult IR = analyzeBlock(BB, EphValues);
2795 if (!IR.isSuccess())
2796 return IR;
2797
2798 Instruction *TI = BB->getTerminator();
2799
2800 // Add in the live successors by first checking whether we have terminator
2801 // that may be simplified based on the values simplified by this call.
2802 if (BranchInst *BI = dyn_cast<BranchInst>(Val: TI)) {
2803 if (BI->isConditional()) {
2804 Value *Cond = BI->getCondition();
2805 if (ConstantInt *SimpleCond =
2806 dyn_cast_or_null<ConstantInt>(Val: SimplifiedValues.lookup(Val: Cond))) {
2807 BasicBlock *NextBB = BI->getSuccessor(i: SimpleCond->isZero() ? 1 : 0);
2808 BBWorklist.insert(X: NextBB);
2809 KnownSuccessors[BB] = NextBB;
2810 findDeadBlocks(CurrBB: BB, NextBB);
2811 continue;
2812 }
2813 }
2814 } else if (SwitchInst *SI = dyn_cast<SwitchInst>(Val: TI)) {
2815 Value *Cond = SI->getCondition();
2816 if (ConstantInt *SimpleCond =
2817 dyn_cast_or_null<ConstantInt>(Val: SimplifiedValues.lookup(Val: Cond))) {
2818 BasicBlock *NextBB = SI->findCaseValue(C: SimpleCond)->getCaseSuccessor();
2819 BBWorklist.insert(X: NextBB);
2820 KnownSuccessors[BB] = NextBB;
2821 findDeadBlocks(CurrBB: BB, NextBB);
2822 continue;
2823 }
2824 }
2825
2826 // If we're unable to select a particular successor, just count all of
2827 // them.
2828 for (BasicBlock *Succ : successors(BB))
2829 BBWorklist.insert(X: Succ);
2830
2831 onBlockAnalyzed(BB);
2832 }
2833
2834 // If this is a noduplicate call, we can still inline as long as
2835 // inlining this would cause the removal of the caller (so the instruction
2836 // is not actually duplicated, just moved).
2837 if (!isSoleCallToLocalFunction(CB: CandidateCall, Callee: F) && ContainsNoDuplicateCall)
2838 return InlineResult::failure(Reason: "noduplicate");
2839
2840 // If the callee's stack size exceeds the user-specified threshold,
2841 // do not let it be inlined.
2842 // The command line option overrides a limit set in the function attributes.
2843 size_t FinalStackSizeThreshold = StackSizeThreshold;
2844 if (!StackSizeThreshold.getNumOccurrences())
2845 if (std::optional<int> AttrMaxStackSize = getStringFnAttrAsInt(
2846 F: Caller, AttrKind: InlineConstants::MaxInlineStackSizeAttributeName))
2847 FinalStackSizeThreshold = *AttrMaxStackSize;
2848 if (AllocatedSize > FinalStackSizeThreshold)
2849 return InlineResult::failure(Reason: "stacksize");
2850
2851 return finalizeAnalysis();
2852}
2853
2854void InlineCostCallAnalyzer::print(raw_ostream &OS) {
2855#define DEBUG_PRINT_STAT(x) OS << " " #x ": " << x << "\n"
2856 if (PrintInstructionComments)
2857 F.print(OS, AAW: &Writer);
2858 DEBUG_PRINT_STAT(NumConstantArgs);
2859 DEBUG_PRINT_STAT(NumConstantOffsetPtrArgs);
2860 DEBUG_PRINT_STAT(NumAllocaArgs);
2861 DEBUG_PRINT_STAT(NumConstantPtrCmps);
2862 DEBUG_PRINT_STAT(NumConstantPtrDiffs);
2863 DEBUG_PRINT_STAT(NumInstructionsSimplified);
2864 DEBUG_PRINT_STAT(NumInstructions);
2865 DEBUG_PRINT_STAT(SROACostSavings);
2866 DEBUG_PRINT_STAT(SROACostSavingsLost);
2867 DEBUG_PRINT_STAT(LoadEliminationCost);
2868 DEBUG_PRINT_STAT(ContainsNoDuplicateCall);
2869 DEBUG_PRINT_STAT(Cost);
2870 DEBUG_PRINT_STAT(Threshold);
2871#undef DEBUG_PRINT_STAT
2872}
2873
2874#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
2875/// Dump stats about this call's analysis.
2876LLVM_DUMP_METHOD void InlineCostCallAnalyzer::dump() { print(dbgs()); }
2877#endif
2878
2879/// Test that there are no attribute conflicts between Caller and Callee
2880/// that prevent inlining.
2881static bool functionsHaveCompatibleAttributes(
2882 Function *Caller, Function *Callee, TargetTransformInfo &TTI,
2883 function_ref<const TargetLibraryInfo &(Function &)> &GetTLI) {
2884 // Note that CalleeTLI must be a copy not a reference. The legacy pass manager
2885 // caches the most recently created TLI in the TargetLibraryInfoWrapperPass
2886 // object, and always returns the same object (which is overwritten on each
2887 // GetTLI call). Therefore we copy the first result.
2888 auto CalleeTLI = GetTLI(*Callee);
2889 return (IgnoreTTIInlineCompatible ||
2890 TTI.areInlineCompatible(Caller, Callee)) &&
2891 GetTLI(*Caller).areInlineCompatible(CalleeTLI,
2892 AllowCallerSuperset: InlineCallerSupersetNoBuiltin) &&
2893 AttributeFuncs::areInlineCompatible(Caller: *Caller, Callee: *Callee);
2894}
2895
2896int llvm::getCallsiteCost(const TargetTransformInfo &TTI, const CallBase &Call,
2897 const DataLayout &DL) {
2898 int64_t Cost = 0;
2899 for (unsigned I = 0, E = Call.arg_size(); I != E; ++I) {
2900 if (Call.isByValArgument(ArgNo: I)) {
2901 // We approximate the number of loads and stores needed by dividing the
2902 // size of the byval type by the target's pointer size.
2903 PointerType *PTy = cast<PointerType>(Val: Call.getArgOperand(i: I)->getType());
2904 unsigned TypeSize = DL.getTypeSizeInBits(Ty: Call.getParamByValType(ArgNo: I));
2905 unsigned AS = PTy->getAddressSpace();
2906 unsigned PointerSize = DL.getPointerSizeInBits(AS);
2907 // Ceiling division.
2908 unsigned NumStores = (TypeSize + PointerSize - 1) / PointerSize;
2909
2910 // If it generates more than 8 stores it is likely to be expanded as an
2911 // inline memcpy so we take that as an upper bound. Otherwise we assume
2912 // one load and one store per word copied.
2913 // FIXME: The maxStoresPerMemcpy setting from the target should be used
2914 // here instead of a magic number of 8, but it's not available via
2915 // DataLayout.
2916 NumStores = std::min(a: NumStores, b: 8U);
2917
2918 Cost += 2 * NumStores * InstrCost;
2919 } else {
2920 // For non-byval arguments subtract off one instruction per call
2921 // argument.
2922 Cost += InstrCost;
2923 }
2924 }
2925 // The call instruction also disappears after inlining.
2926 Cost += InstrCost;
2927 Cost += TTI.getInlineCallPenalty(F: Call.getCaller(), Call, DefaultCallPenalty: CallPenalty);
2928
2929 return std::min<int64_t>(a: Cost, INT_MAX);
2930}
2931
2932InlineCost llvm::getInlineCost(
2933 CallBase &Call, const InlineParams &Params, TargetTransformInfo &CalleeTTI,
2934 function_ref<AssumptionCache &(Function &)> GetAssumptionCache,
2935 function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
2936 function_ref<BlockFrequencyInfo &(Function &)> GetBFI,
2937 ProfileSummaryInfo *PSI, OptimizationRemarkEmitter *ORE) {
2938 return getInlineCost(Call, Callee: Call.getCalledFunction(), Params, CalleeTTI,
2939 GetAssumptionCache, GetTLI, GetBFI, PSI, ORE);
2940}
2941
2942std::optional<int> llvm::getInliningCostEstimate(
2943 CallBase &Call, TargetTransformInfo &CalleeTTI,
2944 function_ref<AssumptionCache &(Function &)> GetAssumptionCache,
2945 function_ref<BlockFrequencyInfo &(Function &)> GetBFI,
2946 ProfileSummaryInfo *PSI, OptimizationRemarkEmitter *ORE) {
2947 const InlineParams Params = {/* DefaultThreshold*/ 0,
2948 /*HintThreshold*/ {},
2949 /*ColdThreshold*/ {},
2950 /*OptSizeThreshold*/ {},
2951 /*OptMinSizeThreshold*/ {},
2952 /*HotCallSiteThreshold*/ {},
2953 /*LocallyHotCallSiteThreshold*/ {},
2954 /*ColdCallSiteThreshold*/ {},
2955 /*ComputeFullInlineCost*/ true,
2956 /*EnableDeferral*/ true};
2957
2958 InlineCostCallAnalyzer CA(*Call.getCalledFunction(), Call, Params, CalleeTTI,
2959 GetAssumptionCache, GetBFI, PSI, ORE, true,
2960 /*IgnoreThreshold*/ true);
2961 auto R = CA.analyze();
2962 if (!R.isSuccess())
2963 return std::nullopt;
2964 return CA.getCost();
2965}
2966
2967std::optional<InlineCostFeatures> llvm::getInliningCostFeatures(
2968 CallBase &Call, TargetTransformInfo &CalleeTTI,
2969 function_ref<AssumptionCache &(Function &)> GetAssumptionCache,
2970 function_ref<BlockFrequencyInfo &(Function &)> GetBFI,
2971 ProfileSummaryInfo *PSI, OptimizationRemarkEmitter *ORE) {
2972 InlineCostFeaturesAnalyzer CFA(CalleeTTI, GetAssumptionCache, GetBFI, PSI,
2973 ORE, *Call.getCalledFunction(), Call);
2974 auto R = CFA.analyze();
2975 if (!R.isSuccess())
2976 return std::nullopt;
2977 return CFA.features();
2978}
2979
2980std::optional<InlineResult> llvm::getAttributeBasedInliningDecision(
2981 CallBase &Call, Function *Callee, TargetTransformInfo &CalleeTTI,
2982 function_ref<const TargetLibraryInfo &(Function &)> GetTLI) {
2983
2984 // Cannot inline indirect calls.
2985 if (!Callee)
2986 return InlineResult::failure(Reason: "indirect call");
2987
2988 // When callee coroutine function is inlined into caller coroutine function
2989 // before coro-split pass,
2990 // coro-early pass can not handle this quiet well.
2991 // So we won't inline the coroutine function if it have not been unsplited
2992 if (Callee->isPresplitCoroutine())
2993 return InlineResult::failure(Reason: "unsplited coroutine call");
2994
2995 // Never inline calls with byval arguments that does not have the alloca
2996 // address space. Since byval arguments can be replaced with a copy to an
2997 // alloca, the inlined code would need to be adjusted to handle that the
2998 // argument is in the alloca address space (so it is a little bit complicated
2999 // to solve).
3000 unsigned AllocaAS = Callee->getDataLayout().getAllocaAddrSpace();
3001 for (unsigned I = 0, E = Call.arg_size(); I != E; ++I)
3002 if (Call.isByValArgument(ArgNo: I)) {
3003 PointerType *PTy = cast<PointerType>(Val: Call.getArgOperand(i: I)->getType());
3004 if (PTy->getAddressSpace() != AllocaAS)
3005 return InlineResult::failure(Reason: "byval arguments without alloca"
3006 " address space");
3007 }
3008
3009 // Calls to functions with always-inline attributes should be inlined
3010 // whenever possible.
3011 if (Call.hasFnAttr(Kind: Attribute::AlwaysInline)) {
3012 if (Call.getAttributes().hasFnAttr(Kind: Attribute::NoInline))
3013 return InlineResult::failure(Reason: "noinline call site attribute");
3014
3015 auto IsViable = isInlineViable(Callee&: *Callee);
3016 if (IsViable.isSuccess())
3017 return InlineResult::success();
3018 return InlineResult::failure(Reason: IsViable.getFailureReason());
3019 }
3020
3021 // Never inline functions with conflicting attributes (unless callee has
3022 // always-inline attribute).
3023 Function *Caller = Call.getCaller();
3024 if (!functionsHaveCompatibleAttributes(Caller, Callee, TTI&: CalleeTTI, GetTLI))
3025 return InlineResult::failure(Reason: "conflicting attributes");
3026
3027 // Don't inline this call if the caller has the optnone attribute.
3028 if (Caller->hasOptNone())
3029 return InlineResult::failure(Reason: "optnone attribute");
3030
3031 // Don't inline a function that treats null pointer as valid into a caller
3032 // that does not have this attribute.
3033 if (!Caller->nullPointerIsDefined() && Callee->nullPointerIsDefined())
3034 return InlineResult::failure(Reason: "nullptr definitions incompatible");
3035
3036 // Don't inline functions which can be interposed at link-time.
3037 if (Callee->isInterposable())
3038 return InlineResult::failure(Reason: "interposable");
3039
3040 // Don't inline functions marked noinline.
3041 if (Callee->hasFnAttribute(Kind: Attribute::NoInline))
3042 return InlineResult::failure(Reason: "noinline function attribute");
3043
3044 // Don't inline call sites marked noinline.
3045 if (Call.isNoInline())
3046 return InlineResult::failure(Reason: "noinline call site attribute");
3047
3048 return std::nullopt;
3049}
3050
3051InlineCost llvm::getInlineCost(
3052 CallBase &Call, Function *Callee, const InlineParams &Params,
3053 TargetTransformInfo &CalleeTTI,
3054 function_ref<AssumptionCache &(Function &)> GetAssumptionCache,
3055 function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
3056 function_ref<BlockFrequencyInfo &(Function &)> GetBFI,
3057 ProfileSummaryInfo *PSI, OptimizationRemarkEmitter *ORE) {
3058
3059 auto UserDecision =
3060 llvm::getAttributeBasedInliningDecision(Call, Callee, CalleeTTI, GetTLI);
3061
3062 if (UserDecision) {
3063 if (UserDecision->isSuccess())
3064 return llvm::InlineCost::getAlways(Reason: "always inline attribute");
3065 return llvm::InlineCost::getNever(Reason: UserDecision->getFailureReason());
3066 }
3067
3068 LLVM_DEBUG(llvm::dbgs() << " Analyzing call of " << Callee->getName()
3069 << "... (caller:" << Call.getCaller()->getName()
3070 << ")\n");
3071
3072 InlineCostCallAnalyzer CA(*Callee, Call, Params, CalleeTTI,
3073 GetAssumptionCache, GetBFI, PSI, ORE);
3074 InlineResult ShouldInline = CA.analyze();
3075
3076 LLVM_DEBUG(CA.dump());
3077
3078 // Always make cost benefit based decision explicit.
3079 // We use always/never here since threshold is not meaningful,
3080 // as it's not what drives cost-benefit analysis.
3081 if (CA.wasDecidedByCostBenefit()) {
3082 if (ShouldInline.isSuccess())
3083 return InlineCost::getAlways(Reason: "benefit over cost",
3084 CostBenefit: CA.getCostBenefitPair());
3085 else
3086 return InlineCost::getNever(Reason: "cost over benefit", CostBenefit: CA.getCostBenefitPair());
3087 }
3088
3089 if (CA.wasDecidedByCostThreshold())
3090 return InlineCost::get(Cost: CA.getCost(), Threshold: CA.getThreshold(),
3091 StaticBonus: CA.getStaticBonusApplied());
3092
3093 // No details on how the decision was made, simply return always or never.
3094 return ShouldInline.isSuccess()
3095 ? InlineCost::getAlways(Reason: "empty function")
3096 : InlineCost::getNever(Reason: ShouldInline.getFailureReason());
3097}
3098
3099InlineResult llvm::isInlineViable(Function &F) {
3100 bool ReturnsTwice = F.hasFnAttribute(Kind: Attribute::ReturnsTwice);
3101 for (BasicBlock &BB : F) {
3102 // Disallow inlining of functions which contain indirect branches.
3103 if (isa<IndirectBrInst>(Val: BB.getTerminator()))
3104 return InlineResult::failure(Reason: "contains indirect branches");
3105
3106 // Disallow inlining of blockaddresses which are used by non-callbr
3107 // instructions.
3108 if (BB.hasAddressTaken())
3109 for (User *U : BlockAddress::get(BB: &BB)->users())
3110 if (!isa<CallBrInst>(Val: *U))
3111 return InlineResult::failure(Reason: "blockaddress used outside of callbr");
3112
3113 for (auto &II : BB) {
3114 CallBase *Call = dyn_cast<CallBase>(Val: &II);
3115 if (!Call)
3116 continue;
3117
3118 // Disallow recursive calls.
3119 Function *Callee = Call->getCalledFunction();
3120 if (&F == Callee)
3121 return InlineResult::failure(Reason: "recursive call");
3122
3123 // Disallow calls which expose returns-twice to a function not previously
3124 // attributed as such.
3125 if (!ReturnsTwice && isa<CallInst>(Val: Call) &&
3126 cast<CallInst>(Val: Call)->canReturnTwice())
3127 return InlineResult::failure(Reason: "exposes returns-twice attribute");
3128
3129 if (Callee)
3130 switch (Callee->getIntrinsicID()) {
3131 default:
3132 break;
3133 case llvm::Intrinsic::icall_branch_funnel:
3134 // Disallow inlining of @llvm.icall.branch.funnel because current
3135 // backend can't separate call targets from call arguments.
3136 return InlineResult::failure(
3137 Reason: "disallowed inlining of @llvm.icall.branch.funnel");
3138 case llvm::Intrinsic::localescape:
3139 // Disallow inlining functions that call @llvm.localescape. Doing this
3140 // correctly would require major changes to the inliner.
3141 return InlineResult::failure(
3142 Reason: "disallowed inlining of @llvm.localescape");
3143 case llvm::Intrinsic::vastart:
3144 // Disallow inlining of functions that initialize VarArgs with
3145 // va_start.
3146 return InlineResult::failure(
3147 Reason: "contains VarArgs initialized with va_start");
3148 }
3149 }
3150 }
3151
3152 return InlineResult::success();
3153}
3154
3155// APIs to create InlineParams based on command line flags and/or other
3156// parameters.
3157
3158InlineParams llvm::getInlineParams(int Threshold) {
3159 InlineParams Params;
3160
3161 // This field is the threshold to use for a callee by default. This is
3162 // derived from one or more of:
3163 // * optimization or size-optimization levels,
3164 // * a value passed to createFunctionInliningPass function, or
3165 // * the -inline-threshold flag.
3166 // If the -inline-threshold flag is explicitly specified, that is used
3167 // irrespective of anything else.
3168 if (InlineThreshold.getNumOccurrences() > 0)
3169 Params.DefaultThreshold = InlineThreshold;
3170 else
3171 Params.DefaultThreshold = Threshold;
3172
3173 // Set the HintThreshold knob from the -inlinehint-threshold.
3174 Params.HintThreshold = HintThreshold;
3175
3176 // Set the HotCallSiteThreshold knob from the -hot-callsite-threshold.
3177 Params.HotCallSiteThreshold = HotCallSiteThreshold;
3178
3179 // If the -locally-hot-callsite-threshold is explicitly specified, use it to
3180 // populate LocallyHotCallSiteThreshold. Later, we populate
3181 // Params.LocallyHotCallSiteThreshold from -locally-hot-callsite-threshold if
3182 // we know that optimization level is O3 (in the getInlineParams variant that
3183 // takes the opt and size levels).
3184 // FIXME: Remove this check (and make the assignment unconditional) after
3185 // addressing size regression issues at O2.
3186 if (LocallyHotCallSiteThreshold.getNumOccurrences() > 0)
3187 Params.LocallyHotCallSiteThreshold = LocallyHotCallSiteThreshold;
3188
3189 // Set the ColdCallSiteThreshold knob from the
3190 // -inline-cold-callsite-threshold.
3191 Params.ColdCallSiteThreshold = ColdCallSiteThreshold;
3192
3193 // Set the OptMinSizeThreshold and OptSizeThreshold params only if the
3194 // -inlinehint-threshold commandline option is not explicitly given. If that
3195 // option is present, then its value applies even for callees with size and
3196 // minsize attributes.
3197 // If the -inline-threshold is not specified, set the ColdThreshold from the
3198 // -inlinecold-threshold even if it is not explicitly passed. If
3199 // -inline-threshold is specified, then -inlinecold-threshold needs to be
3200 // explicitly specified to set the ColdThreshold knob
3201 if (InlineThreshold.getNumOccurrences() == 0) {
3202 Params.OptMinSizeThreshold = InlineConstants::OptMinSizeThreshold;
3203 Params.OptSizeThreshold = InlineConstants::OptSizeThreshold;
3204 Params.ColdThreshold = ColdThreshold;
3205 } else if (ColdThreshold.getNumOccurrences() > 0) {
3206 Params.ColdThreshold = ColdThreshold;
3207 }
3208 return Params;
3209}
3210
3211InlineParams llvm::getInlineParams() {
3212 return getInlineParams(Threshold: DefaultThreshold);
3213}
3214
3215// Compute the default threshold for inlining based on the opt level and the
3216// size opt level.
3217static int computeThresholdFromOptLevels(unsigned OptLevel,
3218 unsigned SizeOptLevel) {
3219 if (OptLevel > 2)
3220 return InlineConstants::OptAggressiveThreshold;
3221 if (SizeOptLevel == 1) // -Os
3222 return InlineConstants::OptSizeThreshold;
3223 if (SizeOptLevel == 2) // -Oz
3224 return InlineConstants::OptMinSizeThreshold;
3225 return DefaultThreshold;
3226}
3227
3228InlineParams llvm::getInlineParams(unsigned OptLevel, unsigned SizeOptLevel) {
3229 auto Params =
3230 getInlineParams(Threshold: computeThresholdFromOptLevels(OptLevel, SizeOptLevel));
3231 // At O3, use the value of -locally-hot-callsite-threshold option to populate
3232 // Params.LocallyHotCallSiteThreshold. Below O3, this flag has effect only
3233 // when it is specified explicitly.
3234 if (OptLevel > 2)
3235 Params.LocallyHotCallSiteThreshold = LocallyHotCallSiteThreshold;
3236 return Params;
3237}
3238
3239PreservedAnalyses
3240InlineCostAnnotationPrinterPass::run(Function &F,
3241 FunctionAnalysisManager &FAM) {
3242 PrintInstructionComments = true;
3243 std::function<AssumptionCache &(Function &)> GetAssumptionCache =
3244 [&](Function &F) -> AssumptionCache & {
3245 return FAM.getResult<AssumptionAnalysis>(IR&: F);
3246 };
3247 Module *M = F.getParent();
3248 ProfileSummaryInfo PSI(*M);
3249 DataLayout DL(M);
3250 TargetTransformInfo TTI(DL);
3251 // FIXME: Redesign the usage of InlineParams to expand the scope of this pass.
3252 // In the current implementation, the type of InlineParams doesn't matter as
3253 // the pass serves only for verification of inliner's decisions.
3254 // We can add a flag which determines InlineParams for this run. Right now,
3255 // the default InlineParams are used.
3256 const InlineParams Params = llvm::getInlineParams();
3257 for (BasicBlock &BB : F) {
3258 for (Instruction &I : BB) {
3259 if (CallInst *CI = dyn_cast<CallInst>(Val: &I)) {
3260 Function *CalledFunction = CI->getCalledFunction();
3261 if (!CalledFunction || CalledFunction->isDeclaration())
3262 continue;
3263 OptimizationRemarkEmitter ORE(CalledFunction);
3264 InlineCostCallAnalyzer ICCA(*CalledFunction, *CI, Params, TTI,
3265 GetAssumptionCache, nullptr, &PSI, &ORE);
3266 ICCA.analyze();
3267 OS << " Analyzing call of " << CalledFunction->getName()
3268 << "... (caller:" << CI->getCaller()->getName() << ")\n";
3269 ICCA.print(OS);
3270 OS << "\n";
3271 }
3272 }
3273 }
3274 return PreservedAnalyses::all();
3275}
3276