xref: /freebsd/contrib/llvm-project/llvm/lib/Passes/PassBuilderPipelines.cpp (revision 38a52bd3b5cac3da6f7f6eef3dd050e6aa08ebb3)
1 //===- Construction of pass pipelines -------------------------------------===//
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 /// \file
9 ///
10 /// This file provides the implementation of the PassBuilder based on our
11 /// static pass registry as well as related functionality. It also provides
12 /// helpers to aid in analyzing, debugging, and testing passes and pass
13 /// pipelines.
14 ///
15 //===----------------------------------------------------------------------===//
16 
17 #include "llvm/Analysis/AliasAnalysis.h"
18 #include "llvm/Analysis/BasicAliasAnalysis.h"
19 #include "llvm/Analysis/CGSCCPassManager.h"
20 #include "llvm/Analysis/GlobalsModRef.h"
21 #include "llvm/Analysis/InlineAdvisor.h"
22 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
23 #include "llvm/Analysis/ProfileSummaryInfo.h"
24 #include "llvm/Analysis/ScopedNoAliasAA.h"
25 #include "llvm/Analysis/TypeBasedAliasAnalysis.h"
26 #include "llvm/IR/PassManager.h"
27 #include "llvm/Passes/OptimizationLevel.h"
28 #include "llvm/Passes/PassBuilder.h"
29 #include "llvm/Support/CommandLine.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/PGOOptions.h"
32 #include "llvm/Target/TargetMachine.h"
33 #include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h"
34 #include "llvm/Transforms/Coroutines/CoroCleanup.h"
35 #include "llvm/Transforms/Coroutines/CoroEarly.h"
36 #include "llvm/Transforms/Coroutines/CoroElide.h"
37 #include "llvm/Transforms/Coroutines/CoroSplit.h"
38 #include "llvm/Transforms/IPO/AlwaysInliner.h"
39 #include "llvm/Transforms/IPO/Annotation2Metadata.h"
40 #include "llvm/Transforms/IPO/ArgumentPromotion.h"
41 #include "llvm/Transforms/IPO/Attributor.h"
42 #include "llvm/Transforms/IPO/CalledValuePropagation.h"
43 #include "llvm/Transforms/IPO/ConstantMerge.h"
44 #include "llvm/Transforms/IPO/CrossDSOCFI.h"
45 #include "llvm/Transforms/IPO/DeadArgumentElimination.h"
46 #include "llvm/Transforms/IPO/ElimAvailExtern.h"
47 #include "llvm/Transforms/IPO/ForceFunctionAttrs.h"
48 #include "llvm/Transforms/IPO/FunctionAttrs.h"
49 #include "llvm/Transforms/IPO/GlobalDCE.h"
50 #include "llvm/Transforms/IPO/GlobalOpt.h"
51 #include "llvm/Transforms/IPO/GlobalSplit.h"
52 #include "llvm/Transforms/IPO/HotColdSplitting.h"
53 #include "llvm/Transforms/IPO/IROutliner.h"
54 #include "llvm/Transforms/IPO/InferFunctionAttrs.h"
55 #include "llvm/Transforms/IPO/Inliner.h"
56 #include "llvm/Transforms/IPO/LowerTypeTests.h"
57 #include "llvm/Transforms/IPO/MergeFunctions.h"
58 #include "llvm/Transforms/IPO/ModuleInliner.h"
59 #include "llvm/Transforms/IPO/OpenMPOpt.h"
60 #include "llvm/Transforms/IPO/PartialInlining.h"
61 #include "llvm/Transforms/IPO/SCCP.h"
62 #include "llvm/Transforms/IPO/SampleProfile.h"
63 #include "llvm/Transforms/IPO/SampleProfileProbe.h"
64 #include "llvm/Transforms/IPO/SyntheticCountsPropagation.h"
65 #include "llvm/Transforms/IPO/WholeProgramDevirt.h"
66 #include "llvm/Transforms/InstCombine/InstCombine.h"
67 #include "llvm/Transforms/Instrumentation/CGProfile.h"
68 #include "llvm/Transforms/Instrumentation/ControlHeightReduction.h"
69 #include "llvm/Transforms/Instrumentation/InstrOrderFile.h"
70 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
71 #include "llvm/Transforms/Instrumentation/MemProfiler.h"
72 #include "llvm/Transforms/Instrumentation/PGOInstrumentation.h"
73 #include "llvm/Transforms/Scalar/ADCE.h"
74 #include "llvm/Transforms/Scalar/AlignmentFromAssumptions.h"
75 #include "llvm/Transforms/Scalar/AnnotationRemarks.h"
76 #include "llvm/Transforms/Scalar/BDCE.h"
77 #include "llvm/Transforms/Scalar/CallSiteSplitting.h"
78 #include "llvm/Transforms/Scalar/ConstraintElimination.h"
79 #include "llvm/Transforms/Scalar/CorrelatedValuePropagation.h"
80 #include "llvm/Transforms/Scalar/DFAJumpThreading.h"
81 #include "llvm/Transforms/Scalar/DeadStoreElimination.h"
82 #include "llvm/Transforms/Scalar/DivRemPairs.h"
83 #include "llvm/Transforms/Scalar/EarlyCSE.h"
84 #include "llvm/Transforms/Scalar/Float2Int.h"
85 #include "llvm/Transforms/Scalar/GVN.h"
86 #include "llvm/Transforms/Scalar/IndVarSimplify.h"
87 #include "llvm/Transforms/Scalar/InstSimplifyPass.h"
88 #include "llvm/Transforms/Scalar/JumpThreading.h"
89 #include "llvm/Transforms/Scalar/LICM.h"
90 #include "llvm/Transforms/Scalar/LoopDeletion.h"
91 #include "llvm/Transforms/Scalar/LoopDistribute.h"
92 #include "llvm/Transforms/Scalar/LoopFlatten.h"
93 #include "llvm/Transforms/Scalar/LoopIdiomRecognize.h"
94 #include "llvm/Transforms/Scalar/LoopInstSimplify.h"
95 #include "llvm/Transforms/Scalar/LoopInterchange.h"
96 #include "llvm/Transforms/Scalar/LoopLoadElimination.h"
97 #include "llvm/Transforms/Scalar/LoopPassManager.h"
98 #include "llvm/Transforms/Scalar/LoopRotation.h"
99 #include "llvm/Transforms/Scalar/LoopSimplifyCFG.h"
100 #include "llvm/Transforms/Scalar/LoopSink.h"
101 #include "llvm/Transforms/Scalar/LoopUnrollAndJamPass.h"
102 #include "llvm/Transforms/Scalar/LoopUnrollPass.h"
103 #include "llvm/Transforms/Scalar/LowerConstantIntrinsics.h"
104 #include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
105 #include "llvm/Transforms/Scalar/LowerMatrixIntrinsics.h"
106 #include "llvm/Transforms/Scalar/MemCpyOptimizer.h"
107 #include "llvm/Transforms/Scalar/MergedLoadStoreMotion.h"
108 #include "llvm/Transforms/Scalar/NewGVN.h"
109 #include "llvm/Transforms/Scalar/Reassociate.h"
110 #include "llvm/Transforms/Scalar/SCCP.h"
111 #include "llvm/Transforms/Scalar/SROA.h"
112 #include "llvm/Transforms/Scalar/SimpleLoopUnswitch.h"
113 #include "llvm/Transforms/Scalar/SimplifyCFG.h"
114 #include "llvm/Transforms/Scalar/SpeculativeExecution.h"
115 #include "llvm/Transforms/Scalar/TailRecursionElimination.h"
116 #include "llvm/Transforms/Scalar/WarnMissedTransforms.h"
117 #include "llvm/Transforms/Utils/AddDiscriminators.h"
118 #include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
119 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
120 #include "llvm/Transforms/Utils/InjectTLIMappings.h"
121 #include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
122 #include "llvm/Transforms/Utils/Mem2Reg.h"
123 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
124 #include "llvm/Transforms/Utils/RelLookupTableConverter.h"
125 #include "llvm/Transforms/Utils/SimplifyCFGOptions.h"
126 #include "llvm/Transforms/Vectorize/LoopVectorize.h"
127 #include "llvm/Transforms/Vectorize/SLPVectorizer.h"
128 #include "llvm/Transforms/Vectorize/VectorCombine.h"
129 
130 using namespace llvm;
131 
132 static cl::opt<InliningAdvisorMode> UseInlineAdvisor(
133     "enable-ml-inliner", cl::init(InliningAdvisorMode::Default), cl::Hidden,
134     cl::desc("Enable ML policy for inliner. Currently trained for -Oz only"),
135     cl::values(clEnumValN(InliningAdvisorMode::Default, "default",
136                           "Heuristics-based inliner version."),
137                clEnumValN(InliningAdvisorMode::Development, "development",
138                           "Use development mode (runtime-loadable model)."),
139                clEnumValN(InliningAdvisorMode::Release, "release",
140                           "Use release mode (AOT-compiled model).")));
141 
142 static cl::opt<bool> EnableSyntheticCounts(
143     "enable-npm-synthetic-counts", cl::init(false), cl::Hidden, cl::ZeroOrMore,
144     cl::desc("Run synthetic function entry count generation "
145              "pass"));
146 
147 /// Flag to enable inline deferral during PGO.
148 static cl::opt<bool>
149     EnablePGOInlineDeferral("enable-npm-pgo-inline-deferral", cl::init(true),
150                             cl::Hidden,
151                             cl::desc("Enable inline deferral during PGO"));
152 
153 static cl::opt<bool> EnableMemProfiler("enable-mem-prof", cl::init(false),
154                                        cl::Hidden, cl::ZeroOrMore,
155                                        cl::desc("Enable memory profiler"));
156 
157 static cl::opt<bool> EnableModuleInliner("enable-module-inliner",
158                                          cl::init(false), cl::Hidden,
159                                          cl::desc("Enable module inliner"));
160 
161 static cl::opt<bool> PerformMandatoryInliningsFirst(
162     "mandatory-inlining-first", cl::init(true), cl::Hidden, cl::ZeroOrMore,
163     cl::desc("Perform mandatory inlinings module-wide, before performing "
164              "inlining."));
165 
166 static cl::opt<bool> EnableO3NonTrivialUnswitching(
167     "enable-npm-O3-nontrivial-unswitch", cl::init(true), cl::Hidden,
168     cl::ZeroOrMore, cl::desc("Enable non-trivial loop unswitching for -O3"));
169 
170 static cl::opt<bool> EnableEagerlyInvalidateAnalyses(
171     "eagerly-invalidate-analyses", cl::init(true), cl::Hidden,
172     cl::desc("Eagerly invalidate more analyses in default pipelines"));
173 
174 static cl::opt<bool> EnableNoRerunSimplificationPipeline(
175     "enable-no-rerun-simplification-pipeline", cl::init(false), cl::Hidden,
176     cl::desc(
177         "Prevent running the simplification pipeline on a function more "
178         "than once in the case that SCC mutations cause a function to be "
179         "visited multiple times as long as the function has not been changed"));
180 
181 static cl::opt<bool> EnableMergeFunctions(
182     "enable-merge-functions", cl::init(false), cl::Hidden,
183     cl::desc("Enable function merging as part of the optimization pipeline"));
184 
185 PipelineTuningOptions::PipelineTuningOptions() {
186   LoopInterleaving = true;
187   LoopVectorization = true;
188   SLPVectorization = false;
189   LoopUnrolling = true;
190   ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll;
191   LicmMssaOptCap = SetLicmMssaOptCap;
192   LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap;
193   CallGraphProfile = true;
194   MergeFunctions = EnableMergeFunctions;
195   EagerlyInvalidateAnalyses = EnableEagerlyInvalidateAnalyses;
196 }
197 
198 namespace llvm {
199 
200 extern cl::opt<unsigned> MaxDevirtIterations;
201 extern cl::opt<bool> EnableConstraintElimination;
202 extern cl::opt<bool> EnableFunctionSpecialization;
203 extern cl::opt<bool> EnableGVNHoist;
204 extern cl::opt<bool> EnableGVNSink;
205 extern cl::opt<bool> EnableHotColdSplit;
206 extern cl::opt<bool> EnableIROutliner;
207 extern cl::opt<bool> EnableOrderFileInstrumentation;
208 extern cl::opt<bool> EnableCHR;
209 extern cl::opt<bool> EnableLoopInterchange;
210 extern cl::opt<bool> EnableUnrollAndJam;
211 extern cl::opt<bool> EnableLoopFlatten;
212 extern cl::opt<bool> EnableDFAJumpThreading;
213 extern cl::opt<bool> RunNewGVN;
214 extern cl::opt<bool> RunPartialInlining;
215 extern cl::opt<bool> ExtraVectorizerPasses;
216 
217 extern cl::opt<bool> FlattenedProfileUsed;
218 
219 extern cl::opt<AttributorRunOption> AttributorRun;
220 extern cl::opt<bool> EnableKnowledgeRetention;
221 
222 extern cl::opt<bool> EnableMatrix;
223 
224 extern cl::opt<bool> DisablePreInliner;
225 extern cl::opt<int> PreInlineThreshold;
226 } // namespace llvm
227 
228 void PassBuilder::invokePeepholeEPCallbacks(FunctionPassManager &FPM,
229                                             OptimizationLevel Level) {
230   for (auto &C : PeepholeEPCallbacks)
231     C(FPM, Level);
232 }
233 
234 // Helper to add AnnotationRemarksPass.
235 static void addAnnotationRemarksPass(ModulePassManager &MPM) {
236   FunctionPassManager FPM;
237   FPM.addPass(AnnotationRemarksPass());
238   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
239 }
240 
241 // Helper to check if the current compilation phase is preparing for LTO
242 static bool isLTOPreLink(ThinOrFullLTOPhase Phase) {
243   return Phase == ThinOrFullLTOPhase::ThinLTOPreLink ||
244          Phase == ThinOrFullLTOPhase::FullLTOPreLink;
245 }
246 
247 // TODO: Investigate the cost/benefit of tail call elimination on debugging.
248 FunctionPassManager
249 PassBuilder::buildO1FunctionSimplificationPipeline(OptimizationLevel Level,
250                                                    ThinOrFullLTOPhase Phase) {
251 
252   FunctionPassManager FPM;
253 
254   // Form SSA out of local memory accesses after breaking apart aggregates into
255   // scalars.
256   FPM.addPass(SROAPass());
257 
258   // Catch trivial redundancies
259   FPM.addPass(EarlyCSEPass(true /* Enable mem-ssa. */));
260 
261   // Hoisting of scalars and load expressions.
262   FPM.addPass(
263       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
264   FPM.addPass(InstCombinePass());
265 
266   FPM.addPass(LibCallsShrinkWrapPass());
267 
268   invokePeepholeEPCallbacks(FPM, Level);
269 
270   FPM.addPass(
271       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
272 
273   // Form canonically associated expression trees, and simplify the trees using
274   // basic mathematical properties. For example, this will form (nearly)
275   // minimal multiplication trees.
276   FPM.addPass(ReassociatePass());
277 
278   // Add the primary loop simplification pipeline.
279   // FIXME: Currently this is split into two loop pass pipelines because we run
280   // some function passes in between them. These can and should be removed
281   // and/or replaced by scheduling the loop pass equivalents in the correct
282   // positions. But those equivalent passes aren't powerful enough yet.
283   // Specifically, `SimplifyCFGPass` and `InstCombinePass` are currently still
284   // used. We have `LoopSimplifyCFGPass` which isn't yet powerful enough yet to
285   // fully replace `SimplifyCFGPass`, and the closest to the other we have is
286   // `LoopInstSimplify`.
287   LoopPassManager LPM1, LPM2;
288 
289   // Simplify the loop body. We do this initially to clean up after other loop
290   // passes run, either when iterating on a loop or on inner loops with
291   // implications on the outer loop.
292   LPM1.addPass(LoopInstSimplifyPass());
293   LPM1.addPass(LoopSimplifyCFGPass());
294 
295   // Try to remove as much code from the loop header as possible,
296   // to reduce amount of IR that will have to be duplicated. However,
297   // do not perform speculative hoisting the first time as LICM
298   // will destroy metadata that may not need to be destroyed if run
299   // after loop rotation.
300   // TODO: Investigate promotion cap for O1.
301   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
302                         /*AllowSpeculation=*/false));
303 
304   LPM1.addPass(LoopRotatePass(/* Disable header duplication */ true,
305                               isLTOPreLink(Phase)));
306   // TODO: Investigate promotion cap for O1.
307   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
308                         /*AllowSpeculation=*/true));
309   LPM1.addPass(SimpleLoopUnswitchPass());
310   if (EnableLoopFlatten)
311     LPM1.addPass(LoopFlattenPass());
312 
313   LPM2.addPass(LoopIdiomRecognizePass());
314   LPM2.addPass(IndVarSimplifyPass());
315 
316   for (auto &C : LateLoopOptimizationsEPCallbacks)
317     C(LPM2, Level);
318 
319   LPM2.addPass(LoopDeletionPass());
320 
321   if (EnableLoopInterchange)
322     LPM2.addPass(LoopInterchangePass());
323 
324   // Do not enable unrolling in PreLinkThinLTO phase during sample PGO
325   // because it changes IR to makes profile annotation in back compile
326   // inaccurate. The normal unroller doesn't pay attention to forced full unroll
327   // attributes so we need to make sure and allow the full unroll pass to pay
328   // attention to it.
329   if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink || !PGOOpt ||
330       PGOOpt->Action != PGOOptions::SampleUse)
331     LPM2.addPass(LoopFullUnrollPass(Level.getSpeedupLevel(),
332                                     /* OnlyWhenForced= */ !PTO.LoopUnrolling,
333                                     PTO.ForgetAllSCEVInLoopUnroll));
334 
335   for (auto &C : LoopOptimizerEndEPCallbacks)
336     C(LPM2, Level);
337 
338   // We provide the opt remark emitter pass for LICM to use. We only need to do
339   // this once as it is immutable.
340   FPM.addPass(
341       RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
342   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM1),
343                                               /*UseMemorySSA=*/true,
344                                               /*UseBlockFrequencyInfo=*/true));
345   FPM.addPass(
346       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
347   FPM.addPass(InstCombinePass());
348   // The loop passes in LPM2 (LoopFullUnrollPass) do not preserve MemorySSA.
349   // *All* loop passes must preserve it, in order to be able to use it.
350   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM2),
351                                               /*UseMemorySSA=*/false,
352                                               /*UseBlockFrequencyInfo=*/false));
353 
354   // Delete small array after loop unroll.
355   FPM.addPass(SROAPass());
356 
357   // Specially optimize memory movement as it doesn't look like dataflow in SSA.
358   FPM.addPass(MemCpyOptPass());
359 
360   // Sparse conditional constant propagation.
361   // FIXME: It isn't clear why we do this *after* loop passes rather than
362   // before...
363   FPM.addPass(SCCPPass());
364 
365   // Delete dead bit computations (instcombine runs after to fold away the dead
366   // computations, and then ADCE will run later to exploit any new DCE
367   // opportunities that creates).
368   FPM.addPass(BDCEPass());
369 
370   // Run instcombine after redundancy and dead bit elimination to exploit
371   // opportunities opened up by them.
372   FPM.addPass(InstCombinePass());
373   invokePeepholeEPCallbacks(FPM, Level);
374 
375   FPM.addPass(CoroElidePass());
376 
377   for (auto &C : ScalarOptimizerLateEPCallbacks)
378     C(FPM, Level);
379 
380   // Finally, do an expensive DCE pass to catch all the dead code exposed by
381   // the simplifications and basic cleanup after all the simplifications.
382   // TODO: Investigate if this is too expensive.
383   FPM.addPass(ADCEPass());
384   FPM.addPass(
385       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
386   FPM.addPass(InstCombinePass());
387   invokePeepholeEPCallbacks(FPM, Level);
388 
389   return FPM;
390 }
391 
392 FunctionPassManager
393 PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
394                                                  ThinOrFullLTOPhase Phase) {
395   assert(Level != OptimizationLevel::O0 && "Must request optimizations!");
396 
397   // The O1 pipeline has a separate pipeline creation function to simplify
398   // construction readability.
399   if (Level.getSpeedupLevel() == 1)
400     return buildO1FunctionSimplificationPipeline(Level, Phase);
401 
402   FunctionPassManager FPM;
403 
404   // Form SSA out of local memory accesses after breaking apart aggregates into
405   // scalars.
406   FPM.addPass(SROAPass());
407 
408   // Catch trivial redundancies
409   FPM.addPass(EarlyCSEPass(true /* Enable mem-ssa. */));
410   if (EnableKnowledgeRetention)
411     FPM.addPass(AssumeSimplifyPass());
412 
413   // Hoisting of scalars and load expressions.
414   if (EnableGVNHoist)
415     FPM.addPass(GVNHoistPass());
416 
417   // Global value numbering based sinking.
418   if (EnableGVNSink) {
419     FPM.addPass(GVNSinkPass());
420     FPM.addPass(
421         SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
422   }
423 
424   if (EnableConstraintElimination)
425     FPM.addPass(ConstraintEliminationPass());
426 
427   // Speculative execution if the target has divergent branches; otherwise nop.
428   FPM.addPass(SpeculativeExecutionPass(/* OnlyIfDivergentTarget =*/true));
429 
430   // Optimize based on known information about branches, and cleanup afterward.
431   FPM.addPass(JumpThreadingPass());
432   FPM.addPass(CorrelatedValuePropagationPass());
433 
434   FPM.addPass(
435       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
436   FPM.addPass(InstCombinePass());
437   if (Level == OptimizationLevel::O3)
438     FPM.addPass(AggressiveInstCombinePass());
439 
440   if (!Level.isOptimizingForSize())
441     FPM.addPass(LibCallsShrinkWrapPass());
442 
443   invokePeepholeEPCallbacks(FPM, Level);
444 
445   // For PGO use pipeline, try to optimize memory intrinsics such as memcpy
446   // using the size value profile. Don't perform this when optimizing for size.
447   if (PGOOpt && PGOOpt->Action == PGOOptions::IRUse &&
448       !Level.isOptimizingForSize())
449     FPM.addPass(PGOMemOPSizeOpt());
450 
451   FPM.addPass(TailCallElimPass());
452   FPM.addPass(
453       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
454 
455   // Form canonically associated expression trees, and simplify the trees using
456   // basic mathematical properties. For example, this will form (nearly)
457   // minimal multiplication trees.
458   FPM.addPass(ReassociatePass());
459 
460   // Add the primary loop simplification pipeline.
461   // FIXME: Currently this is split into two loop pass pipelines because we run
462   // some function passes in between them. These can and should be removed
463   // and/or replaced by scheduling the loop pass equivalents in the correct
464   // positions. But those equivalent passes aren't powerful enough yet.
465   // Specifically, `SimplifyCFGPass` and `InstCombinePass` are currently still
466   // used. We have `LoopSimplifyCFGPass` which isn't yet powerful enough yet to
467   // fully replace `SimplifyCFGPass`, and the closest to the other we have is
468   // `LoopInstSimplify`.
469   LoopPassManager LPM1, LPM2;
470 
471   // Simplify the loop body. We do this initially to clean up after other loop
472   // passes run, either when iterating on a loop or on inner loops with
473   // implications on the outer loop.
474   LPM1.addPass(LoopInstSimplifyPass());
475   LPM1.addPass(LoopSimplifyCFGPass());
476 
477   // Try to remove as much code from the loop header as possible,
478   // to reduce amount of IR that will have to be duplicated. However,
479   // do not perform speculative hoisting the first time as LICM
480   // will destroy metadata that may not need to be destroyed if run
481   // after loop rotation.
482   // TODO: Investigate promotion cap for O1.
483   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
484                         /*AllowSpeculation=*/false));
485 
486   // Disable header duplication in loop rotation at -Oz.
487   LPM1.addPass(
488       LoopRotatePass(Level != OptimizationLevel::Oz, isLTOPreLink(Phase)));
489   // TODO: Investigate promotion cap for O1.
490   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
491                         /*AllowSpeculation=*/true));
492   LPM1.addPass(
493       SimpleLoopUnswitchPass(/* NonTrivial */ Level == OptimizationLevel::O3 &&
494                              EnableO3NonTrivialUnswitching));
495   if (EnableLoopFlatten)
496     LPM1.addPass(LoopFlattenPass());
497 
498   LPM2.addPass(LoopIdiomRecognizePass());
499   LPM2.addPass(IndVarSimplifyPass());
500 
501   for (auto &C : LateLoopOptimizationsEPCallbacks)
502     C(LPM2, Level);
503 
504   LPM2.addPass(LoopDeletionPass());
505 
506   if (EnableLoopInterchange)
507     LPM2.addPass(LoopInterchangePass());
508 
509   // Do not enable unrolling in PreLinkThinLTO phase during sample PGO
510   // because it changes IR to makes profile annotation in back compile
511   // inaccurate. The normal unroller doesn't pay attention to forced full unroll
512   // attributes so we need to make sure and allow the full unroll pass to pay
513   // attention to it.
514   if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink || !PGOOpt ||
515       PGOOpt->Action != PGOOptions::SampleUse)
516     LPM2.addPass(LoopFullUnrollPass(Level.getSpeedupLevel(),
517                                     /* OnlyWhenForced= */ !PTO.LoopUnrolling,
518                                     PTO.ForgetAllSCEVInLoopUnroll));
519 
520   for (auto &C : LoopOptimizerEndEPCallbacks)
521     C(LPM2, Level);
522 
523   // We provide the opt remark emitter pass for LICM to use. We only need to do
524   // this once as it is immutable.
525   FPM.addPass(
526       RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
527   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM1),
528                                               /*UseMemorySSA=*/true,
529                                               /*UseBlockFrequencyInfo=*/true));
530   FPM.addPass(
531       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
532   FPM.addPass(InstCombinePass());
533   // The loop passes in LPM2 (LoopIdiomRecognizePass, IndVarSimplifyPass,
534   // LoopDeletionPass and LoopFullUnrollPass) do not preserve MemorySSA.
535   // *All* loop passes must preserve it, in order to be able to use it.
536   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM2),
537                                               /*UseMemorySSA=*/false,
538                                               /*UseBlockFrequencyInfo=*/false));
539 
540   // Delete small array after loop unroll.
541   FPM.addPass(SROAPass());
542 
543   // The matrix extension can introduce large vector operations early, which can
544   // benefit from running vector-combine early on.
545   if (EnableMatrix)
546     FPM.addPass(VectorCombinePass(/*ScalarizationOnly=*/true));
547 
548   // Eliminate redundancies.
549   FPM.addPass(MergedLoadStoreMotionPass());
550   if (RunNewGVN)
551     FPM.addPass(NewGVNPass());
552   else
553     FPM.addPass(GVNPass());
554 
555   // Sparse conditional constant propagation.
556   // FIXME: It isn't clear why we do this *after* loop passes rather than
557   // before...
558   FPM.addPass(SCCPPass());
559 
560   // Delete dead bit computations (instcombine runs after to fold away the dead
561   // computations, and then ADCE will run later to exploit any new DCE
562   // opportunities that creates).
563   FPM.addPass(BDCEPass());
564 
565   // Run instcombine after redundancy and dead bit elimination to exploit
566   // opportunities opened up by them.
567   FPM.addPass(InstCombinePass());
568   invokePeepholeEPCallbacks(FPM, Level);
569 
570   // Re-consider control flow based optimizations after redundancy elimination,
571   // redo DCE, etc.
572   if (EnableDFAJumpThreading && Level.getSizeLevel() == 0)
573     FPM.addPass(DFAJumpThreadingPass());
574 
575   FPM.addPass(JumpThreadingPass());
576   FPM.addPass(CorrelatedValuePropagationPass());
577 
578   // Finally, do an expensive DCE pass to catch all the dead code exposed by
579   // the simplifications and basic cleanup after all the simplifications.
580   // TODO: Investigate if this is too expensive.
581   FPM.addPass(ADCEPass());
582 
583   // Specially optimize memory movement as it doesn't look like dataflow in SSA.
584   FPM.addPass(MemCpyOptPass());
585 
586   FPM.addPass(DSEPass());
587   FPM.addPass(createFunctionToLoopPassAdaptor(
588       LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
589                /*AllowSpeculation=*/true),
590       /*UseMemorySSA=*/true, /*UseBlockFrequencyInfo=*/true));
591 
592   FPM.addPass(CoroElidePass());
593 
594   for (auto &C : ScalarOptimizerLateEPCallbacks)
595     C(FPM, Level);
596 
597   FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions()
598                                   .convertSwitchRangeToICmp(true)
599                                   .hoistCommonInsts(true)
600                                   .sinkCommonInsts(true)));
601   FPM.addPass(InstCombinePass());
602   invokePeepholeEPCallbacks(FPM, Level);
603 
604   if (EnableCHR && Level == OptimizationLevel::O3 && PGOOpt &&
605       (PGOOpt->Action == PGOOptions::IRUse ||
606        PGOOpt->Action == PGOOptions::SampleUse))
607     FPM.addPass(ControlHeightReductionPass());
608 
609   return FPM;
610 }
611 
612 void PassBuilder::addRequiredLTOPreLinkPasses(ModulePassManager &MPM) {
613   MPM.addPass(CanonicalizeAliasesPass());
614   MPM.addPass(NameAnonGlobalPass());
615 }
616 
617 void PassBuilder::addPGOInstrPasses(ModulePassManager &MPM,
618                                     OptimizationLevel Level, bool RunProfileGen,
619                                     bool IsCS, std::string ProfileFile,
620                                     std::string ProfileRemappingFile) {
621   assert(Level != OptimizationLevel::O0 && "Not expecting O0 here!");
622   if (!IsCS && !DisablePreInliner) {
623     InlineParams IP;
624 
625     IP.DefaultThreshold = PreInlineThreshold;
626 
627     // FIXME: The hint threshold has the same value used by the regular inliner
628     // when not optimzing for size. This should probably be lowered after
629     // performance testing.
630     // FIXME: this comment is cargo culted from the old pass manager, revisit).
631     IP.HintThreshold = Level.isOptimizingForSize() ? PreInlineThreshold : 325;
632     ModuleInlinerWrapperPass MIWP(IP);
633     CGSCCPassManager &CGPipeline = MIWP.getPM();
634 
635     FunctionPassManager FPM;
636     FPM.addPass(SROAPass());
637     FPM.addPass(EarlyCSEPass());    // Catch trivial redundancies.
638     FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(
639         true)));                    // Merge & remove basic blocks.
640     FPM.addPass(InstCombinePass()); // Combine silly sequences.
641     invokePeepholeEPCallbacks(FPM, Level);
642 
643     CGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
644         std::move(FPM), PTO.EagerlyInvalidateAnalyses));
645 
646     MPM.addPass(std::move(MIWP));
647 
648     // Delete anything that is now dead to make sure that we don't instrument
649     // dead code. Instrumentation can end up keeping dead code around and
650     // dramatically increase code size.
651     MPM.addPass(GlobalDCEPass());
652   }
653 
654   if (!RunProfileGen) {
655     assert(!ProfileFile.empty() && "Profile use expecting a profile file!");
656     MPM.addPass(PGOInstrumentationUse(ProfileFile, ProfileRemappingFile, IsCS));
657     // Cache ProfileSummaryAnalysis once to avoid the potential need to insert
658     // RequireAnalysisPass for PSI before subsequent non-module passes.
659     MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
660     return;
661   }
662 
663   // Perform PGO instrumentation.
664   MPM.addPass(PGOInstrumentationGen(IsCS));
665 
666   FunctionPassManager FPM;
667   // Disable header duplication in loop rotation at -Oz.
668   FPM.addPass(createFunctionToLoopPassAdaptor(
669       LoopRotatePass(Level != OptimizationLevel::Oz), /*UseMemorySSA=*/false,
670       /*UseBlockFrequencyInfo=*/false));
671   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM),
672                                                 PTO.EagerlyInvalidateAnalyses));
673 
674   // Add the profile lowering pass.
675   InstrProfOptions Options;
676   if (!ProfileFile.empty())
677     Options.InstrProfileOutput = ProfileFile;
678   // Do counter promotion at Level greater than O0.
679   Options.DoCounterPromotion = true;
680   Options.UseBFIInPromotion = IsCS;
681   MPM.addPass(InstrProfiling(Options, IsCS));
682 }
683 
684 void PassBuilder::addPGOInstrPassesForO0(ModulePassManager &MPM,
685                                          bool RunProfileGen, bool IsCS,
686                                          std::string ProfileFile,
687                                          std::string ProfileRemappingFile) {
688   if (!RunProfileGen) {
689     assert(!ProfileFile.empty() && "Profile use expecting a profile file!");
690     MPM.addPass(PGOInstrumentationUse(ProfileFile, ProfileRemappingFile, IsCS));
691     // Cache ProfileSummaryAnalysis once to avoid the potential need to insert
692     // RequireAnalysisPass for PSI before subsequent non-module passes.
693     MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
694     return;
695   }
696 
697   // Perform PGO instrumentation.
698   MPM.addPass(PGOInstrumentationGen(IsCS));
699   // Add the profile lowering pass.
700   InstrProfOptions Options;
701   if (!ProfileFile.empty())
702     Options.InstrProfileOutput = ProfileFile;
703   // Do not do counter promotion at O0.
704   Options.DoCounterPromotion = false;
705   Options.UseBFIInPromotion = IsCS;
706   MPM.addPass(InstrProfiling(Options, IsCS));
707 }
708 
709 static InlineParams getInlineParamsFromOptLevel(OptimizationLevel Level) {
710   return getInlineParams(Level.getSpeedupLevel(), Level.getSizeLevel());
711 }
712 
713 ModuleInlinerWrapperPass
714 PassBuilder::buildInlinerPipeline(OptimizationLevel Level,
715                                   ThinOrFullLTOPhase Phase) {
716   InlineParams IP = getInlineParamsFromOptLevel(Level);
717   if (Phase == ThinOrFullLTOPhase::ThinLTOPreLink && PGOOpt &&
718       PGOOpt->Action == PGOOptions::SampleUse)
719     IP.HotCallSiteThreshold = 0;
720 
721   if (PGOOpt)
722     IP.EnableDeferral = EnablePGOInlineDeferral;
723 
724   ModuleInlinerWrapperPass MIWP(IP, PerformMandatoryInliningsFirst,
725                                 UseInlineAdvisor, MaxDevirtIterations);
726 
727   // Require the GlobalsAA analysis for the module so we can query it within
728   // the CGSCC pipeline.
729   MIWP.addModulePass(RequireAnalysisPass<GlobalsAA, Module>());
730   // Invalidate AAManager so it can be recreated and pick up the newly available
731   // GlobalsAA.
732   MIWP.addModulePass(
733       createModuleToFunctionPassAdaptor(InvalidateAnalysisPass<AAManager>()));
734 
735   // Require the ProfileSummaryAnalysis for the module so we can query it within
736   // the inliner pass.
737   MIWP.addModulePass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
738 
739   // Now begin the main postorder CGSCC pipeline.
740   // FIXME: The current CGSCC pipeline has its origins in the legacy pass
741   // manager and trying to emulate its precise behavior. Much of this doesn't
742   // make a lot of sense and we should revisit the core CGSCC structure.
743   CGSCCPassManager &MainCGPipeline = MIWP.getPM();
744 
745   // Note: historically, the PruneEH pass was run first to deduce nounwind and
746   // generally clean up exception handling overhead. It isn't clear this is
747   // valuable as the inliner doesn't currently care whether it is inlining an
748   // invoke or a call.
749 
750   if (AttributorRun & AttributorRunOption::CGSCC)
751     MainCGPipeline.addPass(AttributorCGSCCPass());
752 
753   // Now deduce any function attributes based in the current code.
754   MainCGPipeline.addPass(PostOrderFunctionAttrsPass());
755 
756   // When at O3 add argument promotion to the pass pipeline.
757   // FIXME: It isn't at all clear why this should be limited to O3.
758   if (Level == OptimizationLevel::O3)
759     MainCGPipeline.addPass(ArgumentPromotionPass());
760 
761   // Try to perform OpenMP specific optimizations. This is a (quick!) no-op if
762   // there are no OpenMP runtime calls present in the module.
763   if (Level == OptimizationLevel::O2 || Level == OptimizationLevel::O3)
764     MainCGPipeline.addPass(OpenMPOptCGSCCPass());
765 
766   for (auto &C : CGSCCOptimizerLateEPCallbacks)
767     C(MainCGPipeline, Level);
768 
769   // Lastly, add the core function simplification pipeline nested inside the
770   // CGSCC walk.
771   MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
772       buildFunctionSimplificationPipeline(Level, Phase),
773       PTO.EagerlyInvalidateAnalyses, EnableNoRerunSimplificationPipeline));
774 
775   MainCGPipeline.addPass(CoroSplitPass(Level != OptimizationLevel::O0));
776 
777   if (EnableNoRerunSimplificationPipeline)
778     MIWP.addLateModulePass(createModuleToFunctionPassAdaptor(
779         InvalidateAnalysisPass<ShouldNotRunFunctionPassesAnalysis>()));
780 
781   return MIWP;
782 }
783 
784 ModulePassManager
785 PassBuilder::buildModuleInlinerPipeline(OptimizationLevel Level,
786                                         ThinOrFullLTOPhase Phase) {
787   ModulePassManager MPM;
788 
789   InlineParams IP = getInlineParamsFromOptLevel(Level);
790   if (Phase == ThinOrFullLTOPhase::ThinLTOPreLink && PGOOpt &&
791       PGOOpt->Action == PGOOptions::SampleUse)
792     IP.HotCallSiteThreshold = 0;
793 
794   if (PGOOpt)
795     IP.EnableDeferral = EnablePGOInlineDeferral;
796 
797   // The inline deferral logic is used to avoid losing some
798   // inlining chance in future. It is helpful in SCC inliner, in which
799   // inlining is processed in bottom-up order.
800   // While in module inliner, the inlining order is a priority-based order
801   // by default. The inline deferral is unnecessary there. So we disable the
802   // inline deferral logic in module inliner.
803   IP.EnableDeferral = false;
804 
805   MPM.addPass(ModuleInlinerPass(IP, UseInlineAdvisor));
806 
807   MPM.addPass(createModuleToFunctionPassAdaptor(
808       buildFunctionSimplificationPipeline(Level, Phase),
809       PTO.EagerlyInvalidateAnalyses));
810 
811   MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
812       CoroSplitPass(Level != OptimizationLevel::O0)));
813 
814   return MPM;
815 }
816 
817 ModulePassManager
818 PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
819                                                ThinOrFullLTOPhase Phase) {
820   ModulePassManager MPM;
821 
822   // Place pseudo probe instrumentation as the first pass of the pipeline to
823   // minimize the impact of optimization changes.
824   if (PGOOpt && PGOOpt->PseudoProbeForProfiling &&
825       Phase != ThinOrFullLTOPhase::ThinLTOPostLink)
826     MPM.addPass(SampleProfileProbePass(TM));
827 
828   bool HasSampleProfile = PGOOpt && (PGOOpt->Action == PGOOptions::SampleUse);
829 
830   // In ThinLTO mode, when flattened profile is used, all the available
831   // profile information will be annotated in PreLink phase so there is
832   // no need to load the profile again in PostLink.
833   bool LoadSampleProfile =
834       HasSampleProfile &&
835       !(FlattenedProfileUsed && Phase == ThinOrFullLTOPhase::ThinLTOPostLink);
836 
837   // During the ThinLTO backend phase we perform early indirect call promotion
838   // here, before globalopt. Otherwise imported available_externally functions
839   // look unreferenced and are removed. If we are going to load the sample
840   // profile then defer until later.
841   // TODO: See if we can move later and consolidate with the location where
842   // we perform ICP when we are loading a sample profile.
843   // TODO: We pass HasSampleProfile (whether there was a sample profile file
844   // passed to the compile) to the SamplePGO flag of ICP. This is used to
845   // determine whether the new direct calls are annotated with prof metadata.
846   // Ideally this should be determined from whether the IR is annotated with
847   // sample profile, and not whether the a sample profile was provided on the
848   // command line. E.g. for flattened profiles where we will not be reloading
849   // the sample profile in the ThinLTO backend, we ideally shouldn't have to
850   // provide the sample profile file.
851   if (Phase == ThinOrFullLTOPhase::ThinLTOPostLink && !LoadSampleProfile)
852     MPM.addPass(PGOIndirectCallPromotion(true /* InLTO */, HasSampleProfile));
853 
854   // Do basic inference of function attributes from known properties of system
855   // libraries and other oracles.
856   MPM.addPass(InferFunctionAttrsPass());
857 
858   // Create an early function pass manager to cleanup the output of the
859   // frontend.
860   FunctionPassManager EarlyFPM;
861   // Lower llvm.expect to metadata before attempting transforms.
862   // Compare/branch metadata may alter the behavior of passes like SimplifyCFG.
863   EarlyFPM.addPass(LowerExpectIntrinsicPass());
864   EarlyFPM.addPass(SimplifyCFGPass());
865   EarlyFPM.addPass(SROAPass());
866   EarlyFPM.addPass(EarlyCSEPass());
867   EarlyFPM.addPass(CoroEarlyPass());
868   if (Level == OptimizationLevel::O3)
869     EarlyFPM.addPass(CallSiteSplittingPass());
870 
871   // In SamplePGO ThinLTO backend, we need instcombine before profile annotation
872   // to convert bitcast to direct calls so that they can be inlined during the
873   // profile annotation prepration step.
874   // More details about SamplePGO design can be found in:
875   // https://research.google.com/pubs/pub45290.html
876   // FIXME: revisit how SampleProfileLoad/Inliner/ICP is structured.
877   if (LoadSampleProfile)
878     EarlyFPM.addPass(InstCombinePass());
879   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(EarlyFPM),
880                                                 PTO.EagerlyInvalidateAnalyses));
881 
882   if (LoadSampleProfile) {
883     // Annotate sample profile right after early FPM to ensure freshness of
884     // the debug info.
885     MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
886                                         PGOOpt->ProfileRemappingFile, Phase));
887     // Cache ProfileSummaryAnalysis once to avoid the potential need to insert
888     // RequireAnalysisPass for PSI before subsequent non-module passes.
889     MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
890     // Do not invoke ICP in the LTOPrelink phase as it makes it hard
891     // for the profile annotation to be accurate in the LTO backend.
892     if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink &&
893         Phase != ThinOrFullLTOPhase::FullLTOPreLink)
894       // We perform early indirect call promotion here, before globalopt.
895       // This is important for the ThinLTO backend phase because otherwise
896       // imported available_externally functions look unreferenced and are
897       // removed.
898       MPM.addPass(
899           PGOIndirectCallPromotion(true /* IsInLTO */, true /* SamplePGO */));
900   }
901 
902   // Try to perform OpenMP specific optimizations on the module. This is a
903   // (quick!) no-op if there are no OpenMP runtime calls present in the module.
904   if (Level != OptimizationLevel::O0)
905     MPM.addPass(OpenMPOptPass());
906 
907   if (AttributorRun & AttributorRunOption::MODULE)
908     MPM.addPass(AttributorPass());
909 
910   // Lower type metadata and the type.test intrinsic in the ThinLTO
911   // post link pipeline after ICP. This is to enable usage of the type
912   // tests in ICP sequences.
913   if (Phase == ThinOrFullLTOPhase::ThinLTOPostLink)
914     MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
915 
916   for (auto &C : PipelineEarlySimplificationEPCallbacks)
917     C(MPM, Level);
918 
919   // Specialize functions with IPSCCP.
920   if (EnableFunctionSpecialization && Level == OptimizationLevel::O3)
921     MPM.addPass(FunctionSpecializationPass());
922 
923   // Interprocedural constant propagation now that basic cleanup has occurred
924   // and prior to optimizing globals.
925   // FIXME: This position in the pipeline hasn't been carefully considered in
926   // years, it should be re-analyzed.
927   MPM.addPass(IPSCCPPass());
928 
929   // Attach metadata to indirect call sites indicating the set of functions
930   // they may target at run-time. This should follow IPSCCP.
931   MPM.addPass(CalledValuePropagationPass());
932 
933   // Optimize globals to try and fold them into constants.
934   MPM.addPass(GlobalOptPass());
935 
936   // Promote any localized globals to SSA registers.
937   // FIXME: Should this instead by a run of SROA?
938   // FIXME: We should probably run instcombine and simplifycfg afterward to
939   // delete control flows that are dead once globals have been folded to
940   // constants.
941   MPM.addPass(createModuleToFunctionPassAdaptor(PromotePass()));
942 
943   // Remove any dead arguments exposed by cleanups and constant folding
944   // globals.
945   MPM.addPass(DeadArgumentEliminationPass());
946 
947   // Create a small function pass pipeline to cleanup after all the global
948   // optimizations.
949   FunctionPassManager GlobalCleanupPM;
950   GlobalCleanupPM.addPass(InstCombinePass());
951   invokePeepholeEPCallbacks(GlobalCleanupPM, Level);
952 
953   GlobalCleanupPM.addPass(
954       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
955   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(GlobalCleanupPM),
956                                                 PTO.EagerlyInvalidateAnalyses));
957 
958   // Add all the requested passes for instrumentation PGO, if requested.
959   if (PGOOpt && Phase != ThinOrFullLTOPhase::ThinLTOPostLink &&
960       (PGOOpt->Action == PGOOptions::IRInstr ||
961        PGOOpt->Action == PGOOptions::IRUse)) {
962     addPGOInstrPasses(MPM, Level,
963                       /* RunProfileGen */ PGOOpt->Action == PGOOptions::IRInstr,
964                       /* IsCS */ false, PGOOpt->ProfileFile,
965                       PGOOpt->ProfileRemappingFile);
966     MPM.addPass(PGOIndirectCallPromotion(false, false));
967   }
968   if (PGOOpt && Phase != ThinOrFullLTOPhase::ThinLTOPostLink &&
969       PGOOpt->CSAction == PGOOptions::CSIRInstr)
970     MPM.addPass(PGOInstrumentationGenCreateVar(PGOOpt->CSProfileGenFile));
971 
972   // Synthesize function entry counts for non-PGO compilation.
973   if (EnableSyntheticCounts && !PGOOpt)
974     MPM.addPass(SyntheticCountsPropagation());
975 
976   if (EnableModuleInliner)
977     MPM.addPass(buildModuleInlinerPipeline(Level, Phase));
978   else
979     MPM.addPass(buildInlinerPipeline(Level, Phase));
980 
981   if (EnableMemProfiler && Phase != ThinOrFullLTOPhase::ThinLTOPreLink) {
982     MPM.addPass(createModuleToFunctionPassAdaptor(MemProfilerPass()));
983     MPM.addPass(ModuleMemProfilerPass());
984   }
985 
986   return MPM;
987 }
988 
989 /// TODO: Should LTO cause any differences to this set of passes?
990 void PassBuilder::addVectorPasses(OptimizationLevel Level,
991                                   FunctionPassManager &FPM, bool IsFullLTO) {
992   FPM.addPass(LoopVectorizePass(
993       LoopVectorizeOptions(!PTO.LoopInterleaving, !PTO.LoopVectorization)));
994 
995   if (IsFullLTO) {
996     // The vectorizer may have significantly shortened a loop body; unroll
997     // again. Unroll small loops to hide loop backedge latency and saturate any
998     // parallel execution resources of an out-of-order processor. We also then
999     // need to clean up redundancies and loop invariant code.
1000     // FIXME: It would be really good to use a loop-integrated instruction
1001     // combiner for cleanup here so that the unrolling and LICM can be pipelined
1002     // across the loop nests.
1003     // We do UnrollAndJam in a separate LPM to ensure it happens before unroll
1004     if (EnableUnrollAndJam && PTO.LoopUnrolling)
1005       FPM.addPass(createFunctionToLoopPassAdaptor(
1006           LoopUnrollAndJamPass(Level.getSpeedupLevel())));
1007     FPM.addPass(LoopUnrollPass(LoopUnrollOptions(
1008         Level.getSpeedupLevel(), /*OnlyWhenForced=*/!PTO.LoopUnrolling,
1009         PTO.ForgetAllSCEVInLoopUnroll)));
1010     FPM.addPass(WarnMissedTransformationsPass());
1011   }
1012 
1013   if (!IsFullLTO) {
1014     // Eliminate loads by forwarding stores from the previous iteration to loads
1015     // of the current iteration.
1016     FPM.addPass(LoopLoadEliminationPass());
1017   }
1018   // Cleanup after the loop optimization passes.
1019   FPM.addPass(InstCombinePass());
1020 
1021   if (Level.getSpeedupLevel() > 1 && ExtraVectorizerPasses) {
1022     ExtraVectorPassManager ExtraPasses;
1023     // At higher optimization levels, try to clean up any runtime overlap and
1024     // alignment checks inserted by the vectorizer. We want to track correlated
1025     // runtime checks for two inner loops in the same outer loop, fold any
1026     // common computations, hoist loop-invariant aspects out of any outer loop,
1027     // and unswitch the runtime checks if possible. Once hoisted, we may have
1028     // dead (or speculatable) control flows or more combining opportunities.
1029     ExtraPasses.addPass(EarlyCSEPass());
1030     ExtraPasses.addPass(CorrelatedValuePropagationPass());
1031     ExtraPasses.addPass(InstCombinePass());
1032     LoopPassManager LPM;
1033     LPM.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
1034                          /*AllowSpeculation=*/true));
1035     LPM.addPass(SimpleLoopUnswitchPass(/* NonTrivial */ Level ==
1036                                        OptimizationLevel::O3));
1037     ExtraPasses.addPass(
1038         RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
1039     ExtraPasses.addPass(
1040         createFunctionToLoopPassAdaptor(std::move(LPM), /*UseMemorySSA=*/true,
1041                                         /*UseBlockFrequencyInfo=*/true));
1042     ExtraPasses.addPass(
1043         SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
1044     ExtraPasses.addPass(InstCombinePass());
1045     FPM.addPass(std::move(ExtraPasses));
1046   }
1047 
1048   // Now that we've formed fast to execute loop structures, we do further
1049   // optimizations. These are run afterward as they might block doing complex
1050   // analyses and transforms such as what are needed for loop vectorization.
1051 
1052   // Cleanup after loop vectorization, etc. Simplification passes like CVP and
1053   // GVN, loop transforms, and others have already run, so it's now better to
1054   // convert to more optimized IR using more aggressive simplify CFG options.
1055   // The extra sinking transform can create larger basic blocks, so do this
1056   // before SLP vectorization.
1057   FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions()
1058                                   .forwardSwitchCondToPhi(true)
1059                                   .convertSwitchRangeToICmp(true)
1060                                   .convertSwitchToLookupTable(true)
1061                                   .needCanonicalLoops(false)
1062                                   .hoistCommonInsts(true)
1063                                   .sinkCommonInsts(true)));
1064 
1065   if (IsFullLTO) {
1066     FPM.addPass(SCCPPass());
1067     FPM.addPass(InstCombinePass());
1068     FPM.addPass(BDCEPass());
1069   }
1070 
1071   // Optimize parallel scalar instruction chains into SIMD instructions.
1072   if (PTO.SLPVectorization) {
1073     FPM.addPass(SLPVectorizerPass());
1074     if (Level.getSpeedupLevel() > 1 && ExtraVectorizerPasses) {
1075       FPM.addPass(EarlyCSEPass());
1076     }
1077   }
1078   // Enhance/cleanup vector code.
1079   FPM.addPass(VectorCombinePass());
1080 
1081   if (!IsFullLTO) {
1082     FPM.addPass(InstCombinePass());
1083     // Unroll small loops to hide loop backedge latency and saturate any
1084     // parallel execution resources of an out-of-order processor. We also then
1085     // need to clean up redundancies and loop invariant code.
1086     // FIXME: It would be really good to use a loop-integrated instruction
1087     // combiner for cleanup here so that the unrolling and LICM can be pipelined
1088     // across the loop nests.
1089     // We do UnrollAndJam in a separate LPM to ensure it happens before unroll
1090     if (EnableUnrollAndJam && PTO.LoopUnrolling) {
1091       FPM.addPass(createFunctionToLoopPassAdaptor(
1092           LoopUnrollAndJamPass(Level.getSpeedupLevel())));
1093     }
1094     FPM.addPass(LoopUnrollPass(LoopUnrollOptions(
1095         Level.getSpeedupLevel(), /*OnlyWhenForced=*/!PTO.LoopUnrolling,
1096         PTO.ForgetAllSCEVInLoopUnroll)));
1097     FPM.addPass(WarnMissedTransformationsPass());
1098     FPM.addPass(InstCombinePass());
1099     FPM.addPass(
1100         RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
1101     FPM.addPass(createFunctionToLoopPassAdaptor(
1102         LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
1103                  /*AllowSpeculation=*/true),
1104         /*UseMemorySSA=*/true, /*UseBlockFrequencyInfo=*/true));
1105   }
1106 
1107   // Now that we've vectorized and unrolled loops, we may have more refined
1108   // alignment information, try to re-derive it here.
1109   FPM.addPass(AlignmentFromAssumptionsPass());
1110 
1111   if (IsFullLTO)
1112     FPM.addPass(InstCombinePass());
1113 }
1114 
1115 ModulePassManager
1116 PassBuilder::buildModuleOptimizationPipeline(OptimizationLevel Level,
1117                                              bool LTOPreLink) {
1118   ModulePassManager MPM;
1119 
1120   // Optimize globals now that the module is fully simplified.
1121   MPM.addPass(GlobalOptPass());
1122   MPM.addPass(GlobalDCEPass());
1123 
1124   // Run partial inlining pass to partially inline functions that have
1125   // large bodies.
1126   if (RunPartialInlining)
1127     MPM.addPass(PartialInlinerPass());
1128 
1129   // Remove avail extern fns and globals definitions since we aren't compiling
1130   // an object file for later LTO. For LTO we want to preserve these so they
1131   // are eligible for inlining at link-time. Note if they are unreferenced they
1132   // will be removed by GlobalDCE later, so this only impacts referenced
1133   // available externally globals. Eventually they will be suppressed during
1134   // codegen, but eliminating here enables more opportunity for GlobalDCE as it
1135   // may make globals referenced by available external functions dead and saves
1136   // running remaining passes on the eliminated functions. These should be
1137   // preserved during prelinking for link-time inlining decisions.
1138   if (!LTOPreLink)
1139     MPM.addPass(EliminateAvailableExternallyPass());
1140 
1141   if (EnableOrderFileInstrumentation)
1142     MPM.addPass(InstrOrderFilePass());
1143 
1144   // Do RPO function attribute inference across the module to forward-propagate
1145   // attributes where applicable.
1146   // FIXME: Is this really an optimization rather than a canonicalization?
1147   MPM.addPass(ReversePostOrderFunctionAttrsPass());
1148 
1149   // Do a post inline PGO instrumentation and use pass. This is a context
1150   // sensitive PGO pass. We don't want to do this in LTOPreLink phrase as
1151   // cross-module inline has not been done yet. The context sensitive
1152   // instrumentation is after all the inlines are done.
1153   if (!LTOPreLink && PGOOpt) {
1154     if (PGOOpt->CSAction == PGOOptions::CSIRInstr)
1155       addPGOInstrPasses(MPM, Level, /* RunProfileGen */ true,
1156                         /* IsCS */ true, PGOOpt->CSProfileGenFile,
1157                         PGOOpt->ProfileRemappingFile);
1158     else if (PGOOpt->CSAction == PGOOptions::CSIRUse)
1159       addPGOInstrPasses(MPM, Level, /* RunProfileGen */ false,
1160                         /* IsCS */ true, PGOOpt->ProfileFile,
1161                         PGOOpt->ProfileRemappingFile);
1162   }
1163 
1164   // Re-require GloblasAA here prior to function passes. This is particularly
1165   // useful as the above will have inlined, DCE'ed, and function-attr
1166   // propagated everything. We should at this point have a reasonably minimal
1167   // and richly annotated call graph. By computing aliasing and mod/ref
1168   // information for all local globals here, the late loop passes and notably
1169   // the vectorizer will be able to use them to help recognize vectorizable
1170   // memory operations.
1171   MPM.addPass(RequireAnalysisPass<GlobalsAA, Module>());
1172 
1173   FunctionPassManager OptimizePM;
1174   OptimizePM.addPass(Float2IntPass());
1175   OptimizePM.addPass(LowerConstantIntrinsicsPass());
1176 
1177   if (EnableMatrix) {
1178     OptimizePM.addPass(LowerMatrixIntrinsicsPass());
1179     OptimizePM.addPass(EarlyCSEPass());
1180   }
1181 
1182   // FIXME: We need to run some loop optimizations to re-rotate loops after
1183   // simplifycfg and others undo their rotation.
1184 
1185   // Optimize the loop execution. These passes operate on entire loop nests
1186   // rather than on each loop in an inside-out manner, and so they are actually
1187   // function passes.
1188 
1189   for (auto &C : VectorizerStartEPCallbacks)
1190     C(OptimizePM, Level);
1191 
1192   LoopPassManager LPM;
1193   // First rotate loops that may have been un-rotated by prior passes.
1194   // Disable header duplication at -Oz.
1195   LPM.addPass(LoopRotatePass(Level != OptimizationLevel::Oz, LTOPreLink));
1196   // Some loops may have become dead by now. Try to delete them.
1197   // FIXME: see discussion in https://reviews.llvm.org/D112851,
1198   //        this may need to be revisited once we run GVN before loop deletion
1199   //        in the simplification pipeline.
1200   LPM.addPass(LoopDeletionPass());
1201   OptimizePM.addPass(createFunctionToLoopPassAdaptor(
1202       std::move(LPM), /*UseMemorySSA=*/false, /*UseBlockFrequencyInfo=*/false));
1203 
1204   // Distribute loops to allow partial vectorization.  I.e. isolate dependences
1205   // into separate loop that would otherwise inhibit vectorization.  This is
1206   // currently only performed for loops marked with the metadata
1207   // llvm.loop.distribute=true or when -enable-loop-distribute is specified.
1208   OptimizePM.addPass(LoopDistributePass());
1209 
1210   // Populates the VFABI attribute with the scalar-to-vector mappings
1211   // from the TargetLibraryInfo.
1212   OptimizePM.addPass(InjectTLIMappings());
1213 
1214   addVectorPasses(Level, OptimizePM, /* IsFullLTO */ false);
1215 
1216   // LoopSink pass sinks instructions hoisted by LICM, which serves as a
1217   // canonicalization pass that enables other optimizations. As a result,
1218   // LoopSink pass needs to be a very late IR pass to avoid undoing LICM
1219   // result too early.
1220   OptimizePM.addPass(LoopSinkPass());
1221 
1222   // And finally clean up LCSSA form before generating code.
1223   OptimizePM.addPass(InstSimplifyPass());
1224 
1225   // This hoists/decomposes div/rem ops. It should run after other sink/hoist
1226   // passes to avoid re-sinking, but before SimplifyCFG because it can allow
1227   // flattening of blocks.
1228   OptimizePM.addPass(DivRemPairsPass());
1229 
1230   // LoopSink (and other loop passes since the last simplifyCFG) might have
1231   // resulted in single-entry-single-exit or empty blocks. Clean up the CFG.
1232   OptimizePM.addPass(
1233       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
1234 
1235   OptimizePM.addPass(CoroCleanupPass());
1236 
1237   // Add the core optimizing pipeline.
1238   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(OptimizePM),
1239                                                 PTO.EagerlyInvalidateAnalyses));
1240 
1241   for (auto &C : OptimizerLastEPCallbacks)
1242     C(MPM, Level);
1243 
1244   // Split out cold code. Splitting is done late to avoid hiding context from
1245   // other optimizations and inadvertently regressing performance. The tradeoff
1246   // is that this has a higher code size cost than splitting early.
1247   if (EnableHotColdSplit && !LTOPreLink)
1248     MPM.addPass(HotColdSplittingPass());
1249 
1250   // Search the code for similar regions of code. If enough similar regions can
1251   // be found where extracting the regions into their own function will decrease
1252   // the size of the program, we extract the regions, a deduplicate the
1253   // structurally similar regions.
1254   if (EnableIROutliner)
1255     MPM.addPass(IROutlinerPass());
1256 
1257   // Merge functions if requested.
1258   if (PTO.MergeFunctions)
1259     MPM.addPass(MergeFunctionsPass());
1260 
1261   if (PTO.CallGraphProfile)
1262     MPM.addPass(CGProfilePass());
1263 
1264   // Now we need to do some global optimization transforms.
1265   // FIXME: It would seem like these should come first in the optimization
1266   // pipeline and maybe be the bottom of the canonicalization pipeline? Weird
1267   // ordering here.
1268   MPM.addPass(GlobalDCEPass());
1269   MPM.addPass(ConstantMergePass());
1270 
1271   // TODO: Relative look table converter pass caused an issue when full lto is
1272   // enabled. See https://reviews.llvm.org/D94355 for more details.
1273   // Until the issue fixed, disable this pass during pre-linking phase.
1274   if (!LTOPreLink)
1275     MPM.addPass(RelLookupTableConverterPass());
1276 
1277   return MPM;
1278 }
1279 
1280 ModulePassManager
1281 PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
1282                                            bool LTOPreLink) {
1283   assert(Level != OptimizationLevel::O0 &&
1284          "Must request optimizations for the default pipeline!");
1285 
1286   ModulePassManager MPM;
1287 
1288   // Convert @llvm.global.annotations to !annotation metadata.
1289   MPM.addPass(Annotation2MetadataPass());
1290 
1291   // Force any function attributes we want the rest of the pipeline to observe.
1292   MPM.addPass(ForceFunctionAttrsPass());
1293 
1294   // Apply module pipeline start EP callback.
1295   for (auto &C : PipelineStartEPCallbacks)
1296     C(MPM, Level);
1297 
1298   if (PGOOpt && PGOOpt->DebugInfoForProfiling)
1299     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
1300 
1301   // Add the core simplification pipeline.
1302   MPM.addPass(buildModuleSimplificationPipeline(
1303       Level, LTOPreLink ? ThinOrFullLTOPhase::FullLTOPreLink
1304                         : ThinOrFullLTOPhase::None));
1305 
1306   // Now add the optimization pipeline.
1307   MPM.addPass(buildModuleOptimizationPipeline(Level, LTOPreLink));
1308 
1309   if (PGOOpt && PGOOpt->PseudoProbeForProfiling &&
1310       PGOOpt->Action == PGOOptions::SampleUse)
1311     MPM.addPass(PseudoProbeUpdatePass());
1312 
1313   // Emit annotation remarks.
1314   addAnnotationRemarksPass(MPM);
1315 
1316   if (LTOPreLink)
1317     addRequiredLTOPreLinkPasses(MPM);
1318 
1319   return MPM;
1320 }
1321 
1322 ModulePassManager
1323 PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level) {
1324   assert(Level != OptimizationLevel::O0 &&
1325          "Must request optimizations for the default pipeline!");
1326 
1327   ModulePassManager MPM;
1328 
1329   // Convert @llvm.global.annotations to !annotation metadata.
1330   MPM.addPass(Annotation2MetadataPass());
1331 
1332   // Force any function attributes we want the rest of the pipeline to observe.
1333   MPM.addPass(ForceFunctionAttrsPass());
1334 
1335   if (PGOOpt && PGOOpt->DebugInfoForProfiling)
1336     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
1337 
1338   // Apply module pipeline start EP callback.
1339   for (auto &C : PipelineStartEPCallbacks)
1340     C(MPM, Level);
1341 
1342   // If we are planning to perform ThinLTO later, we don't bloat the code with
1343   // unrolling/vectorization/... now. Just simplify the module as much as we
1344   // can.
1345   MPM.addPass(buildModuleSimplificationPipeline(
1346       Level, ThinOrFullLTOPhase::ThinLTOPreLink));
1347 
1348   // Run partial inlining pass to partially inline functions that have
1349   // large bodies.
1350   // FIXME: It isn't clear whether this is really the right place to run this
1351   // in ThinLTO. Because there is another canonicalization and simplification
1352   // phase that will run after the thin link, running this here ends up with
1353   // less information than will be available later and it may grow functions in
1354   // ways that aren't beneficial.
1355   if (RunPartialInlining)
1356     MPM.addPass(PartialInlinerPass());
1357 
1358   // Reduce the size of the IR as much as possible.
1359   MPM.addPass(GlobalOptPass());
1360 
1361   // Module simplification splits coroutines, but does not fully clean up
1362   // coroutine intrinsics. To ensure ThinLTO optimization passes don't trip up
1363   // on these, we schedule the cleanup here.
1364   MPM.addPass(createModuleToFunctionPassAdaptor(CoroCleanupPass()));
1365 
1366   if (PGOOpt && PGOOpt->PseudoProbeForProfiling &&
1367       PGOOpt->Action == PGOOptions::SampleUse)
1368     MPM.addPass(PseudoProbeUpdatePass());
1369 
1370   // Handle OptimizerLastEPCallbacks added by clang on PreLink. Actual
1371   // optimization is going to be done in PostLink stage, but clang can't
1372   // add callbacks there in case of in-process ThinLTO called by linker.
1373   for (auto &C : OptimizerLastEPCallbacks)
1374     C(MPM, Level);
1375 
1376   // Emit annotation remarks.
1377   addAnnotationRemarksPass(MPM);
1378 
1379   addRequiredLTOPreLinkPasses(MPM);
1380 
1381   return MPM;
1382 }
1383 
1384 ModulePassManager PassBuilder::buildThinLTODefaultPipeline(
1385     OptimizationLevel Level, const ModuleSummaryIndex *ImportSummary) {
1386   ModulePassManager MPM;
1387 
1388   // Convert @llvm.global.annotations to !annotation metadata.
1389   MPM.addPass(Annotation2MetadataPass());
1390 
1391   if (ImportSummary) {
1392     // These passes import type identifier resolutions for whole-program
1393     // devirtualization and CFI. They must run early because other passes may
1394     // disturb the specific instruction patterns that these passes look for,
1395     // creating dependencies on resolutions that may not appear in the summary.
1396     //
1397     // For example, GVN may transform the pattern assume(type.test) appearing in
1398     // two basic blocks into assume(phi(type.test, type.test)), which would
1399     // transform a dependency on a WPD resolution into a dependency on a type
1400     // identifier resolution for CFI.
1401     //
1402     // Also, WPD has access to more precise information than ICP and can
1403     // devirtualize more effectively, so it should operate on the IR first.
1404     //
1405     // The WPD and LowerTypeTest passes need to run at -O0 to lower type
1406     // metadata and intrinsics.
1407     MPM.addPass(WholeProgramDevirtPass(nullptr, ImportSummary));
1408     MPM.addPass(LowerTypeTestsPass(nullptr, ImportSummary));
1409   }
1410 
1411   if (Level == OptimizationLevel::O0) {
1412     // Run a second time to clean up any type tests left behind by WPD for use
1413     // in ICP.
1414     MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
1415     // Drop available_externally and unreferenced globals. This is necessary
1416     // with ThinLTO in order to avoid leaving undefined references to dead
1417     // globals in the object file.
1418     MPM.addPass(EliminateAvailableExternallyPass());
1419     MPM.addPass(GlobalDCEPass());
1420     return MPM;
1421   }
1422 
1423   // Force any function attributes we want the rest of the pipeline to observe.
1424   MPM.addPass(ForceFunctionAttrsPass());
1425 
1426   // Add the core simplification pipeline.
1427   MPM.addPass(buildModuleSimplificationPipeline(
1428       Level, ThinOrFullLTOPhase::ThinLTOPostLink));
1429 
1430   // Now add the optimization pipeline.
1431   MPM.addPass(buildModuleOptimizationPipeline(Level));
1432 
1433   // Emit annotation remarks.
1434   addAnnotationRemarksPass(MPM);
1435 
1436   return MPM;
1437 }
1438 
1439 ModulePassManager
1440 PassBuilder::buildLTOPreLinkDefaultPipeline(OptimizationLevel Level) {
1441   assert(Level != OptimizationLevel::O0 &&
1442          "Must request optimizations for the default pipeline!");
1443   // FIXME: We should use a customized pre-link pipeline!
1444   return buildPerModuleDefaultPipeline(Level,
1445                                        /* LTOPreLink */ true);
1446 }
1447 
1448 ModulePassManager
1449 PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
1450                                      ModuleSummaryIndex *ExportSummary) {
1451   ModulePassManager MPM;
1452 
1453   // Convert @llvm.global.annotations to !annotation metadata.
1454   MPM.addPass(Annotation2MetadataPass());
1455 
1456   // Create a function that performs CFI checks for cross-DSO calls with targets
1457   // in the current module.
1458   MPM.addPass(CrossDSOCFIPass());
1459 
1460   if (Level == OptimizationLevel::O0) {
1461     // The WPD and LowerTypeTest passes need to run at -O0 to lower type
1462     // metadata and intrinsics.
1463     MPM.addPass(WholeProgramDevirtPass(ExportSummary, nullptr));
1464     MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
1465     // Run a second time to clean up any type tests left behind by WPD for use
1466     // in ICP.
1467     MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
1468 
1469     // Emit annotation remarks.
1470     addAnnotationRemarksPass(MPM);
1471 
1472     return MPM;
1473   }
1474 
1475   if (PGOOpt && PGOOpt->Action == PGOOptions::SampleUse) {
1476     // Load sample profile before running the LTO optimization pipeline.
1477     MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
1478                                         PGOOpt->ProfileRemappingFile,
1479                                         ThinOrFullLTOPhase::FullLTOPostLink));
1480     // Cache ProfileSummaryAnalysis once to avoid the potential need to insert
1481     // RequireAnalysisPass for PSI before subsequent non-module passes.
1482     MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
1483   }
1484 
1485   // Try to run OpenMP optimizations, quick no-op if no OpenMP metadata present.
1486   MPM.addPass(OpenMPOptPass());
1487 
1488   // Remove unused virtual tables to improve the quality of code generated by
1489   // whole-program devirtualization and bitset lowering.
1490   MPM.addPass(GlobalDCEPass());
1491 
1492   // Force any function attributes we want the rest of the pipeline to observe.
1493   MPM.addPass(ForceFunctionAttrsPass());
1494 
1495   // Do basic inference of function attributes from known properties of system
1496   // libraries and other oracles.
1497   MPM.addPass(InferFunctionAttrsPass());
1498 
1499   if (Level.getSpeedupLevel() > 1) {
1500     FunctionPassManager EarlyFPM;
1501     EarlyFPM.addPass(CallSiteSplittingPass());
1502     MPM.addPass(createModuleToFunctionPassAdaptor(
1503         std::move(EarlyFPM), PTO.EagerlyInvalidateAnalyses));
1504 
1505     // Indirect call promotion. This should promote all the targets that are
1506     // left by the earlier promotion pass that promotes intra-module targets.
1507     // This two-step promotion is to save the compile time. For LTO, it should
1508     // produce the same result as if we only do promotion here.
1509     MPM.addPass(PGOIndirectCallPromotion(
1510         true /* InLTO */, PGOOpt && PGOOpt->Action == PGOOptions::SampleUse));
1511 
1512     if (EnableFunctionSpecialization && Level == OptimizationLevel::O3)
1513       MPM.addPass(FunctionSpecializationPass());
1514     // Propagate constants at call sites into the functions they call.  This
1515     // opens opportunities for globalopt (and inlining) by substituting function
1516     // pointers passed as arguments to direct uses of functions.
1517     MPM.addPass(IPSCCPPass());
1518 
1519     // Attach metadata to indirect call sites indicating the set of functions
1520     // they may target at run-time. This should follow IPSCCP.
1521     MPM.addPass(CalledValuePropagationPass());
1522   }
1523 
1524   // Now deduce any function attributes based in the current code.
1525   MPM.addPass(
1526       createModuleToPostOrderCGSCCPassAdaptor(PostOrderFunctionAttrsPass()));
1527 
1528   // Do RPO function attribute inference across the module to forward-propagate
1529   // attributes where applicable.
1530   // FIXME: Is this really an optimization rather than a canonicalization?
1531   MPM.addPass(ReversePostOrderFunctionAttrsPass());
1532 
1533   // Use in-range annotations on GEP indices to split globals where beneficial.
1534   MPM.addPass(GlobalSplitPass());
1535 
1536   // Run whole program optimization of virtual call when the list of callees
1537   // is fixed.
1538   MPM.addPass(WholeProgramDevirtPass(ExportSummary, nullptr));
1539 
1540   // Stop here at -O1.
1541   if (Level == OptimizationLevel::O1) {
1542     // The LowerTypeTestsPass needs to run to lower type metadata and the
1543     // type.test intrinsics. The pass does nothing if CFI is disabled.
1544     MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
1545     // Run a second time to clean up any type tests left behind by WPD for use
1546     // in ICP (which is performed earlier than this in the regular LTO
1547     // pipeline).
1548     MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
1549 
1550     // Emit annotation remarks.
1551     addAnnotationRemarksPass(MPM);
1552 
1553     return MPM;
1554   }
1555 
1556   // Optimize globals to try and fold them into constants.
1557   MPM.addPass(GlobalOptPass());
1558 
1559   // Promote any localized globals to SSA registers.
1560   MPM.addPass(createModuleToFunctionPassAdaptor(PromotePass()));
1561 
1562   // Linking modules together can lead to duplicate global constant, only
1563   // keep one copy of each constant.
1564   MPM.addPass(ConstantMergePass());
1565 
1566   // Remove unused arguments from functions.
1567   MPM.addPass(DeadArgumentEliminationPass());
1568 
1569   // Reduce the code after globalopt and ipsccp.  Both can open up significant
1570   // simplification opportunities, and both can propagate functions through
1571   // function pointers.  When this happens, we often have to resolve varargs
1572   // calls, etc, so let instcombine do this.
1573   FunctionPassManager PeepholeFPM;
1574   PeepholeFPM.addPass(InstCombinePass());
1575   if (Level == OptimizationLevel::O3)
1576     PeepholeFPM.addPass(AggressiveInstCombinePass());
1577   invokePeepholeEPCallbacks(PeepholeFPM, Level);
1578 
1579   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(PeepholeFPM),
1580                                                 PTO.EagerlyInvalidateAnalyses));
1581 
1582   // Note: historically, the PruneEH pass was run first to deduce nounwind and
1583   // generally clean up exception handling overhead. It isn't clear this is
1584   // valuable as the inliner doesn't currently care whether it is inlining an
1585   // invoke or a call.
1586   // Run the inliner now.
1587   MPM.addPass(ModuleInlinerWrapperPass(getInlineParamsFromOptLevel(Level)));
1588 
1589   // Optimize globals again after we ran the inliner.
1590   MPM.addPass(GlobalOptPass());
1591 
1592   // Garbage collect dead functions.
1593   MPM.addPass(GlobalDCEPass());
1594 
1595   // If we didn't decide to inline a function, check to see if we can
1596   // transform it to pass arguments by value instead of by reference.
1597   MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(ArgumentPromotionPass()));
1598 
1599   FunctionPassManager FPM;
1600   // The IPO Passes may leave cruft around. Clean up after them.
1601   FPM.addPass(InstCombinePass());
1602   invokePeepholeEPCallbacks(FPM, Level);
1603 
1604   FPM.addPass(JumpThreadingPass(/*InsertFreezeWhenUnfoldingSelect*/ true));
1605 
1606   // Do a post inline PGO instrumentation and use pass. This is a context
1607   // sensitive PGO pass.
1608   if (PGOOpt) {
1609     if (PGOOpt->CSAction == PGOOptions::CSIRInstr)
1610       addPGOInstrPasses(MPM, Level, /* RunProfileGen */ true,
1611                         /* IsCS */ true, PGOOpt->CSProfileGenFile,
1612                         PGOOpt->ProfileRemappingFile);
1613     else if (PGOOpt->CSAction == PGOOptions::CSIRUse)
1614       addPGOInstrPasses(MPM, Level, /* RunProfileGen */ false,
1615                         /* IsCS */ true, PGOOpt->ProfileFile,
1616                         PGOOpt->ProfileRemappingFile);
1617   }
1618 
1619   // Break up allocas
1620   FPM.addPass(SROAPass());
1621 
1622   // LTO provides additional opportunities for tailcall elimination due to
1623   // link-time inlining, and visibility of nocapture attribute.
1624   FPM.addPass(TailCallElimPass());
1625 
1626   // Run a few AA driver optimizations here and now to cleanup the code.
1627   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM),
1628                                                 PTO.EagerlyInvalidateAnalyses));
1629 
1630   MPM.addPass(
1631       createModuleToPostOrderCGSCCPassAdaptor(PostOrderFunctionAttrsPass()));
1632 
1633   // Require the GlobalsAA analysis for the module so we can query it within
1634   // MainFPM.
1635   MPM.addPass(RequireAnalysisPass<GlobalsAA, Module>());
1636   // Invalidate AAManager so it can be recreated and pick up the newly available
1637   // GlobalsAA.
1638   MPM.addPass(
1639       createModuleToFunctionPassAdaptor(InvalidateAnalysisPass<AAManager>()));
1640 
1641   FunctionPassManager MainFPM;
1642   MainFPM.addPass(createFunctionToLoopPassAdaptor(
1643       LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
1644                /*AllowSpeculation=*/true),
1645       /*USeMemorySSA=*/true, /*UseBlockFrequencyInfo=*/true));
1646 
1647   if (RunNewGVN)
1648     MainFPM.addPass(NewGVNPass());
1649   else
1650     MainFPM.addPass(GVNPass());
1651 
1652   // Remove dead memcpy()'s.
1653   MainFPM.addPass(MemCpyOptPass());
1654 
1655   // Nuke dead stores.
1656   MainFPM.addPass(DSEPass());
1657   MainFPM.addPass(MergedLoadStoreMotionPass());
1658 
1659 
1660   if (EnableConstraintElimination)
1661     MainFPM.addPass(ConstraintEliminationPass());
1662 
1663   LoopPassManager LPM;
1664   if (EnableLoopFlatten && Level.getSpeedupLevel() > 1)
1665     LPM.addPass(LoopFlattenPass());
1666   LPM.addPass(IndVarSimplifyPass());
1667   LPM.addPass(LoopDeletionPass());
1668   // FIXME: Add loop interchange.
1669 
1670   // Unroll small loops and perform peeling.
1671   LPM.addPass(LoopFullUnrollPass(Level.getSpeedupLevel(),
1672                                  /* OnlyWhenForced= */ !PTO.LoopUnrolling,
1673                                  PTO.ForgetAllSCEVInLoopUnroll));
1674   // The loop passes in LPM (LoopFullUnrollPass) do not preserve MemorySSA.
1675   // *All* loop passes must preserve it, in order to be able to use it.
1676   MainFPM.addPass(createFunctionToLoopPassAdaptor(
1677       std::move(LPM), /*UseMemorySSA=*/false, /*UseBlockFrequencyInfo=*/true));
1678 
1679   MainFPM.addPass(LoopDistributePass());
1680 
1681   addVectorPasses(Level, MainFPM, /* IsFullLTO */ true);
1682 
1683   // Run the OpenMPOpt CGSCC pass again late.
1684   MPM.addPass(
1685       createModuleToPostOrderCGSCCPassAdaptor(OpenMPOptCGSCCPass()));
1686 
1687   invokePeepholeEPCallbacks(MainFPM, Level);
1688   MainFPM.addPass(JumpThreadingPass(/*InsertFreezeWhenUnfoldingSelect*/ true));
1689   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(MainFPM),
1690                                                 PTO.EagerlyInvalidateAnalyses));
1691 
1692   // Lower type metadata and the type.test intrinsic. This pass supports
1693   // clang's control flow integrity mechanisms (-fsanitize=cfi*) and needs
1694   // to be run at link time if CFI is enabled. This pass does nothing if
1695   // CFI is disabled.
1696   MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
1697   // Run a second time to clean up any type tests left behind by WPD for use
1698   // in ICP (which is performed earlier than this in the regular LTO pipeline).
1699   MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
1700 
1701   // Enable splitting late in the FullLTO post-link pipeline. This is done in
1702   // the same stage in the old pass manager (\ref addLateLTOOptimizationPasses).
1703   if (EnableHotColdSplit)
1704     MPM.addPass(HotColdSplittingPass());
1705 
1706   // Add late LTO optimization passes.
1707   // Delete basic blocks, which optimization passes may have killed.
1708   MPM.addPass(createModuleToFunctionPassAdaptor(SimplifyCFGPass(
1709       SimplifyCFGOptions().convertSwitchRangeToICmp(true).hoistCommonInsts(
1710           true))));
1711 
1712   // Drop bodies of available eternally objects to improve GlobalDCE.
1713   MPM.addPass(EliminateAvailableExternallyPass());
1714 
1715   // Now that we have optimized the program, discard unreachable functions.
1716   MPM.addPass(GlobalDCEPass());
1717 
1718   if (PTO.MergeFunctions)
1719     MPM.addPass(MergeFunctionsPass());
1720 
1721   // Emit annotation remarks.
1722   addAnnotationRemarksPass(MPM);
1723 
1724   return MPM;
1725 }
1726 
1727 ModulePassManager PassBuilder::buildO0DefaultPipeline(OptimizationLevel Level,
1728                                                       bool LTOPreLink) {
1729   assert(Level == OptimizationLevel::O0 &&
1730          "buildO0DefaultPipeline should only be used with O0");
1731 
1732   ModulePassManager MPM;
1733 
1734   // Perform pseudo probe instrumentation in O0 mode. This is for the
1735   // consistency between different build modes. For example, a LTO build can be
1736   // mixed with an O0 prelink and an O2 postlink. Loading a sample profile in
1737   // the postlink will require pseudo probe instrumentation in the prelink.
1738   if (PGOOpt && PGOOpt->PseudoProbeForProfiling)
1739     MPM.addPass(SampleProfileProbePass(TM));
1740 
1741   if (PGOOpt && (PGOOpt->Action == PGOOptions::IRInstr ||
1742                  PGOOpt->Action == PGOOptions::IRUse))
1743     addPGOInstrPassesForO0(
1744         MPM,
1745         /* RunProfileGen */ (PGOOpt->Action == PGOOptions::IRInstr),
1746         /* IsCS */ false, PGOOpt->ProfileFile, PGOOpt->ProfileRemappingFile);
1747 
1748   for (auto &C : PipelineStartEPCallbacks)
1749     C(MPM, Level);
1750 
1751   if (PGOOpt && PGOOpt->DebugInfoForProfiling)
1752     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
1753 
1754   for (auto &C : PipelineEarlySimplificationEPCallbacks)
1755     C(MPM, Level);
1756 
1757   // Build a minimal pipeline based on the semantics required by LLVM,
1758   // which is just that always inlining occurs. Further, disable generating
1759   // lifetime intrinsics to avoid enabling further optimizations during
1760   // code generation.
1761   MPM.addPass(AlwaysInlinerPass(
1762       /*InsertLifetimeIntrinsics=*/false));
1763 
1764   if (PTO.MergeFunctions)
1765     MPM.addPass(MergeFunctionsPass());
1766 
1767   if (EnableMatrix)
1768     MPM.addPass(
1769         createModuleToFunctionPassAdaptor(LowerMatrixIntrinsicsPass(true)));
1770 
1771   if (!CGSCCOptimizerLateEPCallbacks.empty()) {
1772     CGSCCPassManager CGPM;
1773     for (auto &C : CGSCCOptimizerLateEPCallbacks)
1774       C(CGPM, Level);
1775     if (!CGPM.isEmpty())
1776       MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPM)));
1777   }
1778   if (!LateLoopOptimizationsEPCallbacks.empty()) {
1779     LoopPassManager LPM;
1780     for (auto &C : LateLoopOptimizationsEPCallbacks)
1781       C(LPM, Level);
1782     if (!LPM.isEmpty()) {
1783       MPM.addPass(createModuleToFunctionPassAdaptor(
1784           createFunctionToLoopPassAdaptor(std::move(LPM))));
1785     }
1786   }
1787   if (!LoopOptimizerEndEPCallbacks.empty()) {
1788     LoopPassManager LPM;
1789     for (auto &C : LoopOptimizerEndEPCallbacks)
1790       C(LPM, Level);
1791     if (!LPM.isEmpty()) {
1792       MPM.addPass(createModuleToFunctionPassAdaptor(
1793           createFunctionToLoopPassAdaptor(std::move(LPM))));
1794     }
1795   }
1796   if (!ScalarOptimizerLateEPCallbacks.empty()) {
1797     FunctionPassManager FPM;
1798     for (auto &C : ScalarOptimizerLateEPCallbacks)
1799       C(FPM, Level);
1800     if (!FPM.isEmpty())
1801       MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
1802   }
1803   if (!VectorizerStartEPCallbacks.empty()) {
1804     FunctionPassManager FPM;
1805     for (auto &C : VectorizerStartEPCallbacks)
1806       C(FPM, Level);
1807     if (!FPM.isEmpty())
1808       MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
1809   }
1810 
1811   MPM.addPass(createModuleToFunctionPassAdaptor(CoroEarlyPass()));
1812   CGSCCPassManager CGPM;
1813   CGPM.addPass(CoroSplitPass());
1814   MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPM)));
1815   MPM.addPass(createModuleToFunctionPassAdaptor(CoroCleanupPass()));
1816 
1817   for (auto &C : OptimizerLastEPCallbacks)
1818     C(MPM, Level);
1819 
1820   if (LTOPreLink)
1821     addRequiredLTOPreLinkPasses(MPM);
1822 
1823   MPM.addPass(createModuleToFunctionPassAdaptor(AnnotationRemarksPass()));
1824 
1825   return MPM;
1826 }
1827 
1828 AAManager PassBuilder::buildDefaultAAPipeline() {
1829   AAManager AA;
1830 
1831   // The order in which these are registered determines their priority when
1832   // being queried.
1833 
1834   // First we register the basic alias analysis that provides the majority of
1835   // per-function local AA logic. This is a stateless, on-demand local set of
1836   // AA techniques.
1837   AA.registerFunctionAnalysis<BasicAA>();
1838 
1839   // Next we query fast, specialized alias analyses that wrap IR-embedded
1840   // information about aliasing.
1841   AA.registerFunctionAnalysis<ScopedNoAliasAA>();
1842   AA.registerFunctionAnalysis<TypeBasedAA>();
1843 
1844   // Add support for querying global aliasing information when available.
1845   // Because the `AAManager` is a function analysis and `GlobalsAA` is a module
1846   // analysis, all that the `AAManager` can do is query for any *cached*
1847   // results from `GlobalsAA` through a readonly proxy.
1848   AA.registerModuleAnalysis<GlobalsAA>();
1849 
1850   // Add target-specific alias analyses.
1851   if (TM)
1852     TM->registerDefaultAliasAnalyses(AA);
1853 
1854   return AA;
1855 }
1856