llvm-project/llvm/lib/Passes/PassBuilderPipelines.cpp
xur-llvm b1ca2a9546
[PGO] Sampled instrumentation in PGO to speed up instrumentation binary (#69535)
In comparison to non-instrumented binaries, PGO instrumentation binaries
can be significantly slower. For highly threaded programs, this slowdown
can
reach 10x due to data races or false sharing within counters.

This patch incorporates sampling into the PGO instrumentation process to
enhance the speed of instrumentation binaries. The fundamental concept
is similar to the one proposed in https://reviews.llvm.org/D63949.

Three sampling modes are introduced:
1. Simple Sampling: When '-sampled-instr-bust-duration' is set to 1.
2. Fast Burst Sampling: When not using simple sampling, and 
'-sampled-instr-period' is set to 65535. This is the default mode of
sampling.
3. Full Burst Sampling: When neither simple nor fast burst sampling is
used.

Utilizing this sampled instrumentation significantly improves the
binary's
execution speed. Measurements show up to 5x speedup with default
settings. Fast burst sampling now results in only around 20% to 30%
slowdown (compared to 8 to 10x slowdown without sampling).

Out tests show that profile quality remains good with sampling,
with edge counts typically showing more than 90% overlap.
For applications whose behavior changes due to binary speed,
sampling instrumentation can enhance performance.
Observations have shown some apps experiencing up to
a ~2% improvement in PGO.

A potential drawback of this patch is the increased binary size
and compilation time. The Sampling method in this patch does
not improve single threaded program instrumentation binary
speed.
2024-07-22 09:19:17 -07:00

2195 lines
91 KiB
C++

//===- Construction of pass pipelines -------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This file provides the implementation of the PassBuilder based on our
/// static pass registry as well as related functionality. It also provides
/// helpers to aid in analyzing, debugging, and testing passes and pass
/// pipelines.
///
//===----------------------------------------------------------------------===//
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/CGSCCPassManager.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/InlineAdvisor.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/ScopedNoAliasAA.h"
#include "llvm/Analysis/TypeBasedAliasAnalysis.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Passes/OptimizationLevel.h"
#include "llvm/Passes/PassBuilder.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/PGOOptions.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h"
#include "llvm/Transforms/Coroutines/CoroCleanup.h"
#include "llvm/Transforms/Coroutines/CoroConditionalWrapper.h"
#include "llvm/Transforms/Coroutines/CoroEarly.h"
#include "llvm/Transforms/Coroutines/CoroElide.h"
#include "llvm/Transforms/Coroutines/CoroSplit.h"
#include "llvm/Transforms/HipStdPar/HipStdPar.h"
#include "llvm/Transforms/IPO/AlwaysInliner.h"
#include "llvm/Transforms/IPO/Annotation2Metadata.h"
#include "llvm/Transforms/IPO/ArgumentPromotion.h"
#include "llvm/Transforms/IPO/Attributor.h"
#include "llvm/Transforms/IPO/CalledValuePropagation.h"
#include "llvm/Transforms/IPO/ConstantMerge.h"
#include "llvm/Transforms/IPO/CrossDSOCFI.h"
#include "llvm/Transforms/IPO/DeadArgumentElimination.h"
#include "llvm/Transforms/IPO/ElimAvailExtern.h"
#include "llvm/Transforms/IPO/EmbedBitcodePass.h"
#include "llvm/Transforms/IPO/ForceFunctionAttrs.h"
#include "llvm/Transforms/IPO/FunctionAttrs.h"
#include "llvm/Transforms/IPO/GlobalDCE.h"
#include "llvm/Transforms/IPO/GlobalOpt.h"
#include "llvm/Transforms/IPO/GlobalSplit.h"
#include "llvm/Transforms/IPO/HotColdSplitting.h"
#include "llvm/Transforms/IPO/IROutliner.h"
#include "llvm/Transforms/IPO/InferFunctionAttrs.h"
#include "llvm/Transforms/IPO/Inliner.h"
#include "llvm/Transforms/IPO/LowerTypeTests.h"
#include "llvm/Transforms/IPO/MemProfContextDisambiguation.h"
#include "llvm/Transforms/IPO/MergeFunctions.h"
#include "llvm/Transforms/IPO/ModuleInliner.h"
#include "llvm/Transforms/IPO/OpenMPOpt.h"
#include "llvm/Transforms/IPO/PartialInlining.h"
#include "llvm/Transforms/IPO/SCCP.h"
#include "llvm/Transforms/IPO/SampleProfile.h"
#include "llvm/Transforms/IPO/SampleProfileProbe.h"
#include "llvm/Transforms/IPO/SyntheticCountsPropagation.h"
#include "llvm/Transforms/IPO/WholeProgramDevirt.h"
#include "llvm/Transforms/InstCombine/InstCombine.h"
#include "llvm/Transforms/Instrumentation/CGProfile.h"
#include "llvm/Transforms/Instrumentation/ControlHeightReduction.h"
#include "llvm/Transforms/Instrumentation/InstrOrderFile.h"
#include "llvm/Transforms/Instrumentation/InstrProfiling.h"
#include "llvm/Transforms/Instrumentation/MemProfiler.h"
#include "llvm/Transforms/Instrumentation/PGOCtxProfLowering.h"
#include "llvm/Transforms/Instrumentation/PGOForceFunctionAttrs.h"
#include "llvm/Transforms/Instrumentation/PGOInstrumentation.h"
#include "llvm/Transforms/Scalar/ADCE.h"
#include "llvm/Transforms/Scalar/AlignmentFromAssumptions.h"
#include "llvm/Transforms/Scalar/AnnotationRemarks.h"
#include "llvm/Transforms/Scalar/BDCE.h"
#include "llvm/Transforms/Scalar/CallSiteSplitting.h"
#include "llvm/Transforms/Scalar/ConstraintElimination.h"
#include "llvm/Transforms/Scalar/CorrelatedValuePropagation.h"
#include "llvm/Transforms/Scalar/DFAJumpThreading.h"
#include "llvm/Transforms/Scalar/DeadStoreElimination.h"
#include "llvm/Transforms/Scalar/DivRemPairs.h"
#include "llvm/Transforms/Scalar/EarlyCSE.h"
#include "llvm/Transforms/Scalar/Float2Int.h"
#include "llvm/Transforms/Scalar/GVN.h"
#include "llvm/Transforms/Scalar/IndVarSimplify.h"
#include "llvm/Transforms/Scalar/InferAlignment.h"
#include "llvm/Transforms/Scalar/InstSimplifyPass.h"
#include "llvm/Transforms/Scalar/JumpTableToSwitch.h"
#include "llvm/Transforms/Scalar/JumpThreading.h"
#include "llvm/Transforms/Scalar/LICM.h"
#include "llvm/Transforms/Scalar/LoopDeletion.h"
#include "llvm/Transforms/Scalar/LoopDistribute.h"
#include "llvm/Transforms/Scalar/LoopFlatten.h"
#include "llvm/Transforms/Scalar/LoopIdiomRecognize.h"
#include "llvm/Transforms/Scalar/LoopInstSimplify.h"
#include "llvm/Transforms/Scalar/LoopInterchange.h"
#include "llvm/Transforms/Scalar/LoopLoadElimination.h"
#include "llvm/Transforms/Scalar/LoopPassManager.h"
#include "llvm/Transforms/Scalar/LoopRotation.h"
#include "llvm/Transforms/Scalar/LoopSimplifyCFG.h"
#include "llvm/Transforms/Scalar/LoopSink.h"
#include "llvm/Transforms/Scalar/LoopUnrollAndJamPass.h"
#include "llvm/Transforms/Scalar/LoopUnrollPass.h"
#include "llvm/Transforms/Scalar/LoopVersioningLICM.h"
#include "llvm/Transforms/Scalar/LowerConstantIntrinsics.h"
#include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
#include "llvm/Transforms/Scalar/LowerMatrixIntrinsics.h"
#include "llvm/Transforms/Scalar/MemCpyOptimizer.h"
#include "llvm/Transforms/Scalar/MergedLoadStoreMotion.h"
#include "llvm/Transforms/Scalar/NewGVN.h"
#include "llvm/Transforms/Scalar/Reassociate.h"
#include "llvm/Transforms/Scalar/SCCP.h"
#include "llvm/Transforms/Scalar/SROA.h"
#include "llvm/Transforms/Scalar/SimpleLoopUnswitch.h"
#include "llvm/Transforms/Scalar/SimplifyCFG.h"
#include "llvm/Transforms/Scalar/SpeculativeExecution.h"
#include "llvm/Transforms/Scalar/TailRecursionElimination.h"
#include "llvm/Transforms/Scalar/WarnMissedTransforms.h"
#include "llvm/Transforms/Utils/AddDiscriminators.h"
#include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
#include "llvm/Transforms/Utils/CanonicalizeAliases.h"
#include "llvm/Transforms/Utils/CountVisits.h"
#include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
#include "llvm/Transforms/Utils/InjectTLIMappings.h"
#include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
#include "llvm/Transforms/Utils/Mem2Reg.h"
#include "llvm/Transforms/Utils/MoveAutoInit.h"
#include "llvm/Transforms/Utils/NameAnonGlobals.h"
#include "llvm/Transforms/Utils/RelLookupTableConverter.h"
#include "llvm/Transforms/Utils/SimplifyCFGOptions.h"
#include "llvm/Transforms/Vectorize/LoopVectorize.h"
#include "llvm/Transforms/Vectorize/SLPVectorizer.h"
#include "llvm/Transforms/Vectorize/VectorCombine.h"
using namespace llvm;
static cl::opt<InliningAdvisorMode> UseInlineAdvisor(
"enable-ml-inliner", cl::init(InliningAdvisorMode::Default), cl::Hidden,
cl::desc("Enable ML policy for inliner. Currently trained for -Oz only"),
cl::values(clEnumValN(InliningAdvisorMode::Default, "default",
"Heuristics-based inliner version"),
clEnumValN(InliningAdvisorMode::Development, "development",
"Use development mode (runtime-loadable model)"),
clEnumValN(InliningAdvisorMode::Release, "release",
"Use release mode (AOT-compiled model)")));
static cl::opt<bool> EnableSyntheticCounts(
"enable-npm-synthetic-counts", cl::Hidden,
cl::desc("Run synthetic function entry count generation "
"pass"));
/// Flag to enable inline deferral during PGO.
static cl::opt<bool>
EnablePGOInlineDeferral("enable-npm-pgo-inline-deferral", cl::init(true),
cl::Hidden,
cl::desc("Enable inline deferral during PGO"));
static cl::opt<bool> EnableModuleInliner("enable-module-inliner",
cl::init(false), cl::Hidden,
cl::desc("Enable module inliner"));
static cl::opt<bool> PerformMandatoryInliningsFirst(
"mandatory-inlining-first", cl::init(false), cl::Hidden,
cl::desc("Perform mandatory inlinings module-wide, before performing "
"inlining"));
static cl::opt<bool> EnableEagerlyInvalidateAnalyses(
"eagerly-invalidate-analyses", cl::init(true), cl::Hidden,
cl::desc("Eagerly invalidate more analyses in default pipelines"));
static cl::opt<bool> EnableMergeFunctions(
"enable-merge-functions", cl::init(false), cl::Hidden,
cl::desc("Enable function merging as part of the optimization pipeline"));
static cl::opt<bool> EnablePostPGOLoopRotation(
"enable-post-pgo-loop-rotation", cl::init(true), cl::Hidden,
cl::desc("Run the loop rotation transformation after PGO instrumentation"));
static cl::opt<bool> EnableGlobalAnalyses(
"enable-global-analyses", cl::init(true), cl::Hidden,
cl::desc("Enable inter-procedural analyses"));
static cl::opt<bool>
RunPartialInlining("enable-partial-inlining", cl::init(false), cl::Hidden,
cl::desc("Run Partial inlinining pass"));
static cl::opt<bool> ExtraVectorizerPasses(
"extra-vectorizer-passes", cl::init(false), cl::Hidden,
cl::desc("Run cleanup optimization passes after vectorization"));
static cl::opt<bool> RunNewGVN("enable-newgvn", cl::init(false), cl::Hidden,
cl::desc("Run the NewGVN pass"));
static cl::opt<bool> EnableLoopInterchange(
"enable-loopinterchange", cl::init(false), cl::Hidden,
cl::desc("Enable the experimental LoopInterchange Pass"));
static cl::opt<bool> EnableUnrollAndJam("enable-unroll-and-jam",
cl::init(false), cl::Hidden,
cl::desc("Enable Unroll And Jam Pass"));
static cl::opt<bool> EnableLoopFlatten("enable-loop-flatten", cl::init(false),
cl::Hidden,
cl::desc("Enable the LoopFlatten Pass"));
// Experimentally allow loop header duplication. This should allow for better
// optimization at Oz, since loop-idiom recognition can then recognize things
// like memcpy. If this ends up being useful for many targets, we should drop
// this flag and make a code generation option that can be controlled
// independent of the opt level and exposed through the frontend.
static cl::opt<bool> EnableLoopHeaderDuplication(
"enable-loop-header-duplication", cl::init(false), cl::Hidden,
cl::desc("Enable loop header duplication at any optimization level"));
static cl::opt<bool>
EnableDFAJumpThreading("enable-dfa-jump-thread",
cl::desc("Enable DFA jump threading"),
cl::init(false), cl::Hidden);
// TODO: turn on and remove flag
static cl::opt<bool> EnablePGOForceFunctionAttrs(
"enable-pgo-force-function-attrs",
cl::desc("Enable pass to set function attributes based on PGO profiles"),
cl::init(false));
static cl::opt<bool>
EnableHotColdSplit("hot-cold-split",
cl::desc("Enable hot-cold splitting pass"));
static cl::opt<bool> EnableIROutliner("ir-outliner", cl::init(false),
cl::Hidden,
cl::desc("Enable ir outliner pass"));
static cl::opt<bool>
DisablePreInliner("disable-preinline", cl::init(false), cl::Hidden,
cl::desc("Disable pre-instrumentation inliner"));
static cl::opt<int> PreInlineThreshold(
"preinline-threshold", cl::Hidden, cl::init(75),
cl::desc("Control the amount of inlining in pre-instrumentation inliner "
"(default = 75)"));
static cl::opt<bool>
EnableGVNHoist("enable-gvn-hoist",
cl::desc("Enable the GVN hoisting pass (default = off)"));
static cl::opt<bool>
EnableGVNSink("enable-gvn-sink",
cl::desc("Enable the GVN sinking pass (default = off)"));
static cl::opt<bool> EnableJumpTableToSwitch(
"enable-jump-table-to-switch",
cl::desc("Enable JumpTableToSwitch pass (default = off)"));
// This option is used in simplifying testing SampleFDO optimizations for
// profile loading.
static cl::opt<bool>
EnableCHR("enable-chr", cl::init(true), cl::Hidden,
cl::desc("Enable control height reduction optimization (CHR)"));
static cl::opt<bool> FlattenedProfileUsed(
"flattened-profile-used", cl::init(false), cl::Hidden,
cl::desc("Indicate the sample profile being used is flattened, i.e., "
"no inline hierachy exists in the profile"));
static cl::opt<bool> EnableOrderFileInstrumentation(
"enable-order-file-instrumentation", cl::init(false), cl::Hidden,
cl::desc("Enable order file instrumentation (default = off)"));
static cl::opt<bool>
EnableMatrix("enable-matrix", cl::init(false), cl::Hidden,
cl::desc("Enable lowering of the matrix intrinsics"));
static cl::opt<bool> EnableConstraintElimination(
"enable-constraint-elimination", cl::init(true), cl::Hidden,
cl::desc(
"Enable pass to eliminate conditions based on linear constraints"));
static cl::opt<AttributorRunOption> AttributorRun(
"attributor-enable", cl::Hidden, cl::init(AttributorRunOption::NONE),
cl::desc("Enable the attributor inter-procedural deduction pass"),
cl::values(clEnumValN(AttributorRunOption::ALL, "all",
"enable all attributor runs"),
clEnumValN(AttributorRunOption::MODULE, "module",
"enable module-wide attributor runs"),
clEnumValN(AttributorRunOption::CGSCC, "cgscc",
"enable call graph SCC attributor runs"),
clEnumValN(AttributorRunOption::NONE, "none",
"disable attributor runs")));
static cl::opt<bool> EnableSampledInstr(
"enable-sampled-instrumentation", cl::init(false), cl::Hidden,
cl::desc("Enable profile instrumentation sampling (default = off)"));
static cl::opt<bool> UseLoopVersioningLICM(
"enable-loop-versioning-licm", cl::init(false), cl::Hidden,
cl::desc("Enable the experimental Loop Versioning LICM pass"));
namespace llvm {
extern cl::opt<bool> EnableMemProfContextDisambiguation;
extern cl::opt<bool> EnableInferAlignmentPass;
} // namespace llvm
PipelineTuningOptions::PipelineTuningOptions() {
LoopInterleaving = true;
LoopVectorization = true;
SLPVectorization = false;
LoopUnrolling = true;
ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll;
LicmMssaOptCap = SetLicmMssaOptCap;
LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap;
CallGraphProfile = true;
UnifiedLTO = false;
MergeFunctions = EnableMergeFunctions;
InlinerThreshold = -1;
EagerlyInvalidateAnalyses = EnableEagerlyInvalidateAnalyses;
}
namespace llvm {
extern cl::opt<unsigned> MaxDevirtIterations;
} // namespace llvm
void PassBuilder::invokePeepholeEPCallbacks(FunctionPassManager &FPM,
OptimizationLevel Level) {
for (auto &C : PeepholeEPCallbacks)
C(FPM, Level);
}
void PassBuilder::invokeLateLoopOptimizationsEPCallbacks(
LoopPassManager &LPM, OptimizationLevel Level) {
for (auto &C : LateLoopOptimizationsEPCallbacks)
C(LPM, Level);
}
void PassBuilder::invokeLoopOptimizerEndEPCallbacks(LoopPassManager &LPM,
OptimizationLevel Level) {
for (auto &C : LoopOptimizerEndEPCallbacks)
C(LPM, Level);
}
void PassBuilder::invokeScalarOptimizerLateEPCallbacks(
FunctionPassManager &FPM, OptimizationLevel Level) {
for (auto &C : ScalarOptimizerLateEPCallbacks)
C(FPM, Level);
}
void PassBuilder::invokeCGSCCOptimizerLateEPCallbacks(CGSCCPassManager &CGPM,
OptimizationLevel Level) {
for (auto &C : CGSCCOptimizerLateEPCallbacks)
C(CGPM, Level);
}
void PassBuilder::invokeVectorizerStartEPCallbacks(FunctionPassManager &FPM,
OptimizationLevel Level) {
for (auto &C : VectorizerStartEPCallbacks)
C(FPM, Level);
}
void PassBuilder::invokeOptimizerEarlyEPCallbacks(ModulePassManager &MPM,
OptimizationLevel Level) {
for (auto &C : OptimizerEarlyEPCallbacks)
C(MPM, Level);
}
void PassBuilder::invokeOptimizerLastEPCallbacks(ModulePassManager &MPM,
OptimizationLevel Level) {
for (auto &C : OptimizerLastEPCallbacks)
C(MPM, Level);
}
void PassBuilder::invokeFullLinkTimeOptimizationEarlyEPCallbacks(
ModulePassManager &MPM, OptimizationLevel Level) {
for (auto &C : FullLinkTimeOptimizationEarlyEPCallbacks)
C(MPM, Level);
}
void PassBuilder::invokeFullLinkTimeOptimizationLastEPCallbacks(
ModulePassManager &MPM, OptimizationLevel Level) {
for (auto &C : FullLinkTimeOptimizationLastEPCallbacks)
C(MPM, Level);
}
void PassBuilder::invokePipelineStartEPCallbacks(ModulePassManager &MPM,
OptimizationLevel Level) {
for (auto &C : PipelineStartEPCallbacks)
C(MPM, Level);
}
void PassBuilder::invokePipelineEarlySimplificationEPCallbacks(
ModulePassManager &MPM, OptimizationLevel Level) {
for (auto &C : PipelineEarlySimplificationEPCallbacks)
C(MPM, Level);
}
// Helper to add AnnotationRemarksPass.
static void addAnnotationRemarksPass(ModulePassManager &MPM) {
MPM.addPass(createModuleToFunctionPassAdaptor(AnnotationRemarksPass()));
}
// Helper to check if the current compilation phase is preparing for LTO
static bool isLTOPreLink(ThinOrFullLTOPhase Phase) {
return Phase == ThinOrFullLTOPhase::ThinLTOPreLink ||
Phase == ThinOrFullLTOPhase::FullLTOPreLink;
}
// TODO: Investigate the cost/benefit of tail call elimination on debugging.
FunctionPassManager
PassBuilder::buildO1FunctionSimplificationPipeline(OptimizationLevel Level,
ThinOrFullLTOPhase Phase) {
FunctionPassManager FPM;
if (AreStatisticsEnabled())
FPM.addPass(CountVisitsPass());
// Form SSA out of local memory accesses after breaking apart aggregates into
// scalars.
FPM.addPass(SROAPass(SROAOptions::ModifyCFG));
// Catch trivial redundancies
FPM.addPass(EarlyCSEPass(true /* Enable mem-ssa. */));
// Hoisting of scalars and load expressions.
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
FPM.addPass(InstCombinePass());
FPM.addPass(LibCallsShrinkWrapPass());
invokePeepholeEPCallbacks(FPM, Level);
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
// Form canonically associated expression trees, and simplify the trees using
// basic mathematical properties. For example, this will form (nearly)
// minimal multiplication trees.
FPM.addPass(ReassociatePass());
// Add the primary loop simplification pipeline.
// FIXME: Currently this is split into two loop pass pipelines because we run
// some function passes in between them. These can and should be removed
// and/or replaced by scheduling the loop pass equivalents in the correct
// positions. But those equivalent passes aren't powerful enough yet.
// Specifically, `SimplifyCFGPass` and `InstCombinePass` are currently still
// used. We have `LoopSimplifyCFGPass` which isn't yet powerful enough yet to
// fully replace `SimplifyCFGPass`, and the closest to the other we have is
// `LoopInstSimplify`.
LoopPassManager LPM1, LPM2;
// Simplify the loop body. We do this initially to clean up after other loop
// passes run, either when iterating on a loop or on inner loops with
// implications on the outer loop.
LPM1.addPass(LoopInstSimplifyPass());
LPM1.addPass(LoopSimplifyCFGPass());
// Try to remove as much code from the loop header as possible,
// to reduce amount of IR that will have to be duplicated. However,
// do not perform speculative hoisting the first time as LICM
// will destroy metadata that may not need to be destroyed if run
// after loop rotation.
// TODO: Investigate promotion cap for O1.
LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/false));
LPM1.addPass(LoopRotatePass(/* Disable header duplication */ true,
isLTOPreLink(Phase)));
// TODO: Investigate promotion cap for O1.
LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/true));
LPM1.addPass(SimpleLoopUnswitchPass());
if (EnableLoopFlatten)
LPM1.addPass(LoopFlattenPass());
LPM2.addPass(LoopIdiomRecognizePass());
LPM2.addPass(IndVarSimplifyPass());
invokeLateLoopOptimizationsEPCallbacks(LPM2, Level);
LPM2.addPass(LoopDeletionPass());
if (EnableLoopInterchange)
LPM2.addPass(LoopInterchangePass());
// Do not enable unrolling in PreLinkThinLTO phase during sample PGO
// because it changes IR to makes profile annotation in back compile
// inaccurate. The normal unroller doesn't pay attention to forced full unroll
// attributes so we need to make sure and allow the full unroll pass to pay
// attention to it.
if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink || !PGOOpt ||
PGOOpt->Action != PGOOptions::SampleUse)
LPM2.addPass(LoopFullUnrollPass(Level.getSpeedupLevel(),
/* OnlyWhenForced= */ !PTO.LoopUnrolling,
PTO.ForgetAllSCEVInLoopUnroll));
invokeLoopOptimizerEndEPCallbacks(LPM2, Level);
FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM1),
/*UseMemorySSA=*/true,
/*UseBlockFrequencyInfo=*/true));
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
FPM.addPass(InstCombinePass());
// The loop passes in LPM2 (LoopFullUnrollPass) do not preserve MemorySSA.
// *All* loop passes must preserve it, in order to be able to use it.
FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM2),
/*UseMemorySSA=*/false,
/*UseBlockFrequencyInfo=*/false));
// Delete small array after loop unroll.
FPM.addPass(SROAPass(SROAOptions::ModifyCFG));
// Specially optimize memory movement as it doesn't look like dataflow in SSA.
FPM.addPass(MemCpyOptPass());
// Sparse conditional constant propagation.
// FIXME: It isn't clear why we do this *after* loop passes rather than
// before...
FPM.addPass(SCCPPass());
// Delete dead bit computations (instcombine runs after to fold away the dead
// computations, and then ADCE will run later to exploit any new DCE
// opportunities that creates).
FPM.addPass(BDCEPass());
// Run instcombine after redundancy and dead bit elimination to exploit
// opportunities opened up by them.
FPM.addPass(InstCombinePass());
invokePeepholeEPCallbacks(FPM, Level);
FPM.addPass(CoroElidePass());
invokeScalarOptimizerLateEPCallbacks(FPM, Level);
// Finally, do an expensive DCE pass to catch all the dead code exposed by
// the simplifications and basic cleanup after all the simplifications.
// TODO: Investigate if this is too expensive.
FPM.addPass(ADCEPass());
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
FPM.addPass(InstCombinePass());
invokePeepholeEPCallbacks(FPM, Level);
return FPM;
}
FunctionPassManager
PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
ThinOrFullLTOPhase Phase) {
assert(Level != OptimizationLevel::O0 && "Must request optimizations!");
// The O1 pipeline has a separate pipeline creation function to simplify
// construction readability.
if (Level.getSpeedupLevel() == 1)
return buildO1FunctionSimplificationPipeline(Level, Phase);
FunctionPassManager FPM;
if (AreStatisticsEnabled())
FPM.addPass(CountVisitsPass());
// Form SSA out of local memory accesses after breaking apart aggregates into
// scalars.
FPM.addPass(SROAPass(SROAOptions::ModifyCFG));
// Catch trivial redundancies
FPM.addPass(EarlyCSEPass(true /* Enable mem-ssa. */));
if (EnableKnowledgeRetention)
FPM.addPass(AssumeSimplifyPass());
// Hoisting of scalars and load expressions.
if (EnableGVNHoist)
FPM.addPass(GVNHoistPass());
// Global value numbering based sinking.
if (EnableGVNSink) {
FPM.addPass(GVNSinkPass());
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
}
// Speculative execution if the target has divergent branches; otherwise nop.
FPM.addPass(SpeculativeExecutionPass(/* OnlyIfDivergentTarget =*/true));
// Optimize based on known information about branches, and cleanup afterward.
FPM.addPass(JumpThreadingPass());
FPM.addPass(CorrelatedValuePropagationPass());
// Jump table to switch conversion.
if (EnableJumpTableToSwitch)
FPM.addPass(JumpTableToSwitchPass());
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
FPM.addPass(InstCombinePass());
FPM.addPass(AggressiveInstCombinePass());
if (!Level.isOptimizingForSize())
FPM.addPass(LibCallsShrinkWrapPass());
invokePeepholeEPCallbacks(FPM, Level);
// For PGO use pipeline, try to optimize memory intrinsics such as memcpy
// using the size value profile. Don't perform this when optimizing for size.
if (PGOOpt && PGOOpt->Action == PGOOptions::IRUse &&
!Level.isOptimizingForSize())
FPM.addPass(PGOMemOPSizeOpt());
FPM.addPass(TailCallElimPass());
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
// Form canonically associated expression trees, and simplify the trees using
// basic mathematical properties. For example, this will form (nearly)
// minimal multiplication trees.
FPM.addPass(ReassociatePass());
if (EnableConstraintElimination)
FPM.addPass(ConstraintEliminationPass());
// Add the primary loop simplification pipeline.
// FIXME: Currently this is split into two loop pass pipelines because we run
// some function passes in between them. These can and should be removed
// and/or replaced by scheduling the loop pass equivalents in the correct
// positions. But those equivalent passes aren't powerful enough yet.
// Specifically, `SimplifyCFGPass` and `InstCombinePass` are currently still
// used. We have `LoopSimplifyCFGPass` which isn't yet powerful enough yet to
// fully replace `SimplifyCFGPass`, and the closest to the other we have is
// `LoopInstSimplify`.
LoopPassManager LPM1, LPM2;
// Simplify the loop body. We do this initially to clean up after other loop
// passes run, either when iterating on a loop or on inner loops with
// implications on the outer loop.
LPM1.addPass(LoopInstSimplifyPass());
LPM1.addPass(LoopSimplifyCFGPass());
// Try to remove as much code from the loop header as possible,
// to reduce amount of IR that will have to be duplicated. However,
// do not perform speculative hoisting the first time as LICM
// will destroy metadata that may not need to be destroyed if run
// after loop rotation.
// TODO: Investigate promotion cap for O1.
LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/false));
// Disable header duplication in loop rotation at -Oz.
LPM1.addPass(LoopRotatePass(EnableLoopHeaderDuplication ||
Level != OptimizationLevel::Oz,
isLTOPreLink(Phase)));
// TODO: Investigate promotion cap for O1.
LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/true));
LPM1.addPass(
SimpleLoopUnswitchPass(/* NonTrivial */ Level == OptimizationLevel::O3));
if (EnableLoopFlatten)
LPM1.addPass(LoopFlattenPass());
LPM2.addPass(LoopIdiomRecognizePass());
LPM2.addPass(IndVarSimplifyPass());
{
ExtraSimpleLoopUnswitchPassManager ExtraPasses;
ExtraPasses.addPass(SimpleLoopUnswitchPass(/* NonTrivial */ Level ==
OptimizationLevel::O3));
LPM2.addPass(std::move(ExtraPasses));
}
invokeLateLoopOptimizationsEPCallbacks(LPM2, Level);
LPM2.addPass(LoopDeletionPass());
if (EnableLoopInterchange)
LPM2.addPass(LoopInterchangePass());
// Do not enable unrolling in PreLinkThinLTO phase during sample PGO
// because it changes IR to makes profile annotation in back compile
// inaccurate. The normal unroller doesn't pay attention to forced full unroll
// attributes so we need to make sure and allow the full unroll pass to pay
// attention to it.
if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink || !PGOOpt ||
PGOOpt->Action != PGOOptions::SampleUse)
LPM2.addPass(LoopFullUnrollPass(Level.getSpeedupLevel(),
/* OnlyWhenForced= */ !PTO.LoopUnrolling,
PTO.ForgetAllSCEVInLoopUnroll));
invokeLoopOptimizerEndEPCallbacks(LPM2, Level);
FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM1),
/*UseMemorySSA=*/true,
/*UseBlockFrequencyInfo=*/true));
FPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
FPM.addPass(InstCombinePass());
// The loop passes in LPM2 (LoopIdiomRecognizePass, IndVarSimplifyPass,
// LoopDeletionPass and LoopFullUnrollPass) do not preserve MemorySSA.
// *All* loop passes must preserve it, in order to be able to use it.
FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM2),
/*UseMemorySSA=*/false,
/*UseBlockFrequencyInfo=*/false));
// Delete small array after loop unroll.
FPM.addPass(SROAPass(SROAOptions::ModifyCFG));
// Try vectorization/scalarization transforms that are both improvements
// themselves and can allow further folds with GVN and InstCombine.
FPM.addPass(VectorCombinePass(/*TryEarlyFoldsOnly=*/true));
// Eliminate redundancies.
FPM.addPass(MergedLoadStoreMotionPass());
if (RunNewGVN)
FPM.addPass(NewGVNPass());
else
FPM.addPass(GVNPass());
// Sparse conditional constant propagation.
// FIXME: It isn't clear why we do this *after* loop passes rather than
// before...
FPM.addPass(SCCPPass());
// Delete dead bit computations (instcombine runs after to fold away the dead
// computations, and then ADCE will run later to exploit any new DCE
// opportunities that creates).
FPM.addPass(BDCEPass());
// Run instcombine after redundancy and dead bit elimination to exploit
// opportunities opened up by them.
FPM.addPass(InstCombinePass());
invokePeepholeEPCallbacks(FPM, Level);
// Re-consider control flow based optimizations after redundancy elimination,
// redo DCE, etc.
if (EnableDFAJumpThreading)
FPM.addPass(DFAJumpThreadingPass());
FPM.addPass(JumpThreadingPass());
FPM.addPass(CorrelatedValuePropagationPass());
// Finally, do an expensive DCE pass to catch all the dead code exposed by
// the simplifications and basic cleanup after all the simplifications.
// TODO: Investigate if this is too expensive.
FPM.addPass(ADCEPass());
// Specially optimize memory movement as it doesn't look like dataflow in SSA.
FPM.addPass(MemCpyOptPass());
FPM.addPass(DSEPass());
FPM.addPass(MoveAutoInitPass());
FPM.addPass(createFunctionToLoopPassAdaptor(
LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/true),
/*UseMemorySSA=*/true, /*UseBlockFrequencyInfo=*/false));
FPM.addPass(CoroElidePass());
invokeScalarOptimizerLateEPCallbacks(FPM, Level);
FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions()
.convertSwitchRangeToICmp(true)
.hoistCommonInsts(true)
.sinkCommonInsts(true)));
FPM.addPass(InstCombinePass());
invokePeepholeEPCallbacks(FPM, Level);
return FPM;
}
void PassBuilder::addRequiredLTOPreLinkPasses(ModulePassManager &MPM) {
MPM.addPass(CanonicalizeAliasesPass());
MPM.addPass(NameAnonGlobalPass());
}
void PassBuilder::addPreInlinerPasses(ModulePassManager &MPM,
OptimizationLevel Level,
ThinOrFullLTOPhase LTOPhase) {
assert(Level != OptimizationLevel::O0 && "Not expecting O0 here!");
if (DisablePreInliner)
return;
InlineParams IP;
IP.DefaultThreshold = PreInlineThreshold;
// FIXME: The hint threshold has the same value used by the regular inliner
// when not optimzing for size. This should probably be lowered after
// performance testing.
// FIXME: this comment is cargo culted from the old pass manager, revisit).
IP.HintThreshold = Level.isOptimizingForSize() ? PreInlineThreshold : 325;
ModuleInlinerWrapperPass MIWP(
IP, /* MandatoryFirst */ true,
InlineContext{LTOPhase, InlinePass::EarlyInliner});
CGSCCPassManager &CGPipeline = MIWP.getPM();
FunctionPassManager FPM;
FPM.addPass(SROAPass(SROAOptions::ModifyCFG));
FPM.addPass(EarlyCSEPass()); // Catch trivial redundancies.
FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(
true))); // Merge & remove basic blocks.
FPM.addPass(InstCombinePass()); // Combine silly sequences.
invokePeepholeEPCallbacks(FPM, Level);
CGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
std::move(FPM), PTO.EagerlyInvalidateAnalyses));
MPM.addPass(std::move(MIWP));
// Delete anything that is now dead to make sure that we don't instrument
// dead code. Instrumentation can end up keeping dead code around and
// dramatically increase code size.
MPM.addPass(GlobalDCEPass());
}
void PassBuilder::addPostPGOLoopRotation(ModulePassManager &MPM,
OptimizationLevel Level) {
if (EnablePostPGOLoopRotation) {
// Disable header duplication in loop rotation at -Oz.
MPM.addPass(createModuleToFunctionPassAdaptor(
createFunctionToLoopPassAdaptor(
LoopRotatePass(EnableLoopHeaderDuplication ||
Level != OptimizationLevel::Oz),
/*UseMemorySSA=*/false,
/*UseBlockFrequencyInfo=*/false),
PTO.EagerlyInvalidateAnalyses));
}
}
void PassBuilder::addPGOInstrPasses(ModulePassManager &MPM,
OptimizationLevel Level, bool RunProfileGen,
bool IsCS, bool AtomicCounterUpdate,
std::string ProfileFile,
std::string ProfileRemappingFile,
IntrusiveRefCntPtr<vfs::FileSystem> FS) {
assert(Level != OptimizationLevel::O0 && "Not expecting O0 here!");
if (!RunProfileGen) {
assert(!ProfileFile.empty() && "Profile use expecting a profile file!");
MPM.addPass(
PGOInstrumentationUse(ProfileFile, ProfileRemappingFile, IsCS, FS));
// Cache ProfileSummaryAnalysis once to avoid the potential need to insert
// RequireAnalysisPass for PSI before subsequent non-module passes.
MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
return;
}
// Perform PGO instrumentation.
MPM.addPass(PGOInstrumentationGen(IsCS));
addPostPGOLoopRotation(MPM, Level);
// Add the profile lowering pass.
InstrProfOptions Options;
if (!ProfileFile.empty())
Options.InstrProfileOutput = ProfileFile;
// Do counter promotion at Level greater than O0.
Options.DoCounterPromotion = true;
Options.UseBFIInPromotion = IsCS;
if (EnableSampledInstr) {
Options.Sampling = true;
// With sampling, there is little beneifit to enable counter promotion.
// But note that sampling does work with counter promotion.
Options.DoCounterPromotion = false;
}
Options.Atomic = AtomicCounterUpdate;
MPM.addPass(InstrProfilingLoweringPass(Options, IsCS));
}
void PassBuilder::addPGOInstrPassesForO0(
ModulePassManager &MPM, bool RunProfileGen, bool IsCS,
bool AtomicCounterUpdate, std::string ProfileFile,
std::string ProfileRemappingFile, IntrusiveRefCntPtr<vfs::FileSystem> FS) {
if (!RunProfileGen) {
assert(!ProfileFile.empty() && "Profile use expecting a profile file!");
MPM.addPass(
PGOInstrumentationUse(ProfileFile, ProfileRemappingFile, IsCS, FS));
// Cache ProfileSummaryAnalysis once to avoid the potential need to insert
// RequireAnalysisPass for PSI before subsequent non-module passes.
MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
return;
}
// Perform PGO instrumentation.
MPM.addPass(PGOInstrumentationGen(IsCS));
// Add the profile lowering pass.
InstrProfOptions Options;
if (!ProfileFile.empty())
Options.InstrProfileOutput = ProfileFile;
// Do not do counter promotion at O0.
Options.DoCounterPromotion = false;
Options.UseBFIInPromotion = IsCS;
Options.Atomic = AtomicCounterUpdate;
MPM.addPass(InstrProfilingLoweringPass(Options, IsCS));
}
static InlineParams getInlineParamsFromOptLevel(OptimizationLevel Level) {
return getInlineParams(Level.getSpeedupLevel(), Level.getSizeLevel());
}
ModuleInlinerWrapperPass
PassBuilder::buildInlinerPipeline(OptimizationLevel Level,
ThinOrFullLTOPhase Phase) {
InlineParams IP;
if (PTO.InlinerThreshold == -1)
IP = getInlineParamsFromOptLevel(Level);
else
IP = getInlineParams(PTO.InlinerThreshold);
// For PreLinkThinLTO + SamplePGO, set hot-caller threshold to 0 to
// disable hot callsite inline (as much as possible [1]) because it makes
// profile annotation in the backend inaccurate.
//
// [1] Note the cost of a function could be below zero due to erased
// prologue / epilogue.
if (Phase == ThinOrFullLTOPhase::ThinLTOPreLink && PGOOpt &&
PGOOpt->Action == PGOOptions::SampleUse)
IP.HotCallSiteThreshold = 0;
if (PGOOpt)
IP.EnableDeferral = EnablePGOInlineDeferral;
ModuleInlinerWrapperPass MIWP(IP, PerformMandatoryInliningsFirst,
InlineContext{Phase, InlinePass::CGSCCInliner},
UseInlineAdvisor, MaxDevirtIterations);
// Require the GlobalsAA analysis for the module so we can query it within
// the CGSCC pipeline.
if (EnableGlobalAnalyses) {
MIWP.addModulePass(RequireAnalysisPass<GlobalsAA, Module>());
// Invalidate AAManager so it can be recreated and pick up the newly
// available GlobalsAA.
MIWP.addModulePass(
createModuleToFunctionPassAdaptor(InvalidateAnalysisPass<AAManager>()));
}
// Require the ProfileSummaryAnalysis for the module so we can query it within
// the inliner pass.
MIWP.addModulePass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
// Now begin the main postorder CGSCC pipeline.
// FIXME: The current CGSCC pipeline has its origins in the legacy pass
// manager and trying to emulate its precise behavior. Much of this doesn't
// make a lot of sense and we should revisit the core CGSCC structure.
CGSCCPassManager &MainCGPipeline = MIWP.getPM();
// Note: historically, the PruneEH pass was run first to deduce nounwind and
// generally clean up exception handling overhead. It isn't clear this is
// valuable as the inliner doesn't currently care whether it is inlining an
// invoke or a call.
if (AttributorRun & AttributorRunOption::CGSCC)
MainCGPipeline.addPass(AttributorCGSCCPass());
// Deduce function attributes. We do another run of this after the function
// simplification pipeline, so this only needs to run when it could affect the
// function simplification pipeline, which is only the case with recursive
// functions.
MainCGPipeline.addPass(PostOrderFunctionAttrsPass(/*SkipNonRecursive*/ true));
// When at O3 add argument promotion to the pass pipeline.
// FIXME: It isn't at all clear why this should be limited to O3.
if (Level == OptimizationLevel::O3)
MainCGPipeline.addPass(ArgumentPromotionPass());
// Try to perform OpenMP specific optimizations. This is a (quick!) no-op if
// there are no OpenMP runtime calls present in the module.
if (Level == OptimizationLevel::O2 || Level == OptimizationLevel::O3)
MainCGPipeline.addPass(OpenMPOptCGSCCPass());
invokeCGSCCOptimizerLateEPCallbacks(MainCGPipeline, Level);
// Add the core function simplification pipeline nested inside the
// CGSCC walk.
MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
buildFunctionSimplificationPipeline(Level, Phase),
PTO.EagerlyInvalidateAnalyses, /*NoRerun=*/true));
// Finally, deduce any function attributes based on the fully simplified
// function.
MainCGPipeline.addPass(PostOrderFunctionAttrsPass());
// Mark that the function is fully simplified and that it shouldn't be
// simplified again if we somehow revisit it due to CGSCC mutations unless
// it's been modified since.
MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
RequireAnalysisPass<ShouldNotRunFunctionPassesAnalysis, Function>()));
MainCGPipeline.addPass(CoroSplitPass(Level != OptimizationLevel::O0));
// Make sure we don't affect potential future NoRerun CGSCC adaptors.
MIWP.addLateModulePass(createModuleToFunctionPassAdaptor(
InvalidateAnalysisPass<ShouldNotRunFunctionPassesAnalysis>()));
return MIWP;
}
ModulePassManager
PassBuilder::buildModuleInlinerPipeline(OptimizationLevel Level,
ThinOrFullLTOPhase Phase) {
ModulePassManager MPM;
InlineParams IP = getInlineParamsFromOptLevel(Level);
// For PreLinkThinLTO + SamplePGO, set hot-caller threshold to 0 to
// disable hot callsite inline (as much as possible [1]) because it makes
// profile annotation in the backend inaccurate.
//
// [1] Note the cost of a function could be below zero due to erased
// prologue / epilogue.
if (Phase == ThinOrFullLTOPhase::ThinLTOPreLink && PGOOpt &&
PGOOpt->Action == PGOOptions::SampleUse)
IP.HotCallSiteThreshold = 0;
if (PGOOpt)
IP.EnableDeferral = EnablePGOInlineDeferral;
// The inline deferral logic is used to avoid losing some
// inlining chance in future. It is helpful in SCC inliner, in which
// inlining is processed in bottom-up order.
// While in module inliner, the inlining order is a priority-based order
// by default. The inline deferral is unnecessary there. So we disable the
// inline deferral logic in module inliner.
IP.EnableDeferral = false;
MPM.addPass(ModuleInlinerPass(IP, UseInlineAdvisor, Phase));
MPM.addPass(createModuleToFunctionPassAdaptor(
buildFunctionSimplificationPipeline(Level, Phase),
PTO.EagerlyInvalidateAnalyses));
MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
CoroSplitPass(Level != OptimizationLevel::O0)));
return MPM;
}
ModulePassManager
PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
ThinOrFullLTOPhase Phase) {
assert(Level != OptimizationLevel::O0 &&
"Should not be used for O0 pipeline");
assert(Phase != ThinOrFullLTOPhase::FullLTOPostLink &&
"FullLTOPostLink shouldn't call buildModuleSimplificationPipeline!");
ModulePassManager MPM;
// Place pseudo probe instrumentation as the first pass of the pipeline to
// minimize the impact of optimization changes.
if (PGOOpt && PGOOpt->PseudoProbeForProfiling &&
Phase != ThinOrFullLTOPhase::ThinLTOPostLink)
MPM.addPass(SampleProfileProbePass(TM));
bool HasSampleProfile = PGOOpt && (PGOOpt->Action == PGOOptions::SampleUse);
// In ThinLTO mode, when flattened profile is used, all the available
// profile information will be annotated in PreLink phase so there is
// no need to load the profile again in PostLink.
bool LoadSampleProfile =
HasSampleProfile &&
!(FlattenedProfileUsed && Phase == ThinOrFullLTOPhase::ThinLTOPostLink);
// During the ThinLTO backend phase we perform early indirect call promotion
// here, before globalopt. Otherwise imported available_externally functions
// look unreferenced and are removed. If we are going to load the sample
// profile then defer until later.
// TODO: See if we can move later and consolidate with the location where
// we perform ICP when we are loading a sample profile.
// TODO: We pass HasSampleProfile (whether there was a sample profile file
// passed to the compile) to the SamplePGO flag of ICP. This is used to
// determine whether the new direct calls are annotated with prof metadata.
// Ideally this should be determined from whether the IR is annotated with
// sample profile, and not whether the a sample profile was provided on the
// command line. E.g. for flattened profiles where we will not be reloading
// the sample profile in the ThinLTO backend, we ideally shouldn't have to
// provide the sample profile file.
if (Phase == ThinOrFullLTOPhase::ThinLTOPostLink && !LoadSampleProfile)
MPM.addPass(PGOIndirectCallPromotion(true /* InLTO */, HasSampleProfile));
// Create an early function pass manager to cleanup the output of the
// frontend. Not necessary with LTO post link pipelines since the pre link
// pipeline already cleaned up the frontend output.
if (Phase != ThinOrFullLTOPhase::ThinLTOPostLink) {
// Do basic inference of function attributes from known properties of system
// libraries and other oracles.
MPM.addPass(InferFunctionAttrsPass());
MPM.addPass(CoroEarlyPass());
FunctionPassManager EarlyFPM;
EarlyFPM.addPass(EntryExitInstrumenterPass(/*PostInlining=*/false));
// Lower llvm.expect to metadata before attempting transforms.
// Compare/branch metadata may alter the behavior of passes like
// SimplifyCFG.
EarlyFPM.addPass(LowerExpectIntrinsicPass());
EarlyFPM.addPass(SimplifyCFGPass());
EarlyFPM.addPass(SROAPass(SROAOptions::ModifyCFG));
EarlyFPM.addPass(EarlyCSEPass());
if (Level == OptimizationLevel::O3)
EarlyFPM.addPass(CallSiteSplittingPass());
MPM.addPass(createModuleToFunctionPassAdaptor(
std::move(EarlyFPM), PTO.EagerlyInvalidateAnalyses));
}
if (LoadSampleProfile) {
// Annotate sample profile right after early FPM to ensure freshness of
// the debug info.
MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
PGOOpt->ProfileRemappingFile, Phase));
// Cache ProfileSummaryAnalysis once to avoid the potential need to insert
// RequireAnalysisPass for PSI before subsequent non-module passes.
MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
// Do not invoke ICP in the LTOPrelink phase as it makes it hard
// for the profile annotation to be accurate in the LTO backend.
if (!isLTOPreLink(Phase))
// We perform early indirect call promotion here, before globalopt.
// This is important for the ThinLTO backend phase because otherwise
// imported available_externally functions look unreferenced and are
// removed.
MPM.addPass(
PGOIndirectCallPromotion(true /* IsInLTO */, true /* SamplePGO */));
}
// Try to perform OpenMP specific optimizations on the module. This is a
// (quick!) no-op if there are no OpenMP runtime calls present in the module.
MPM.addPass(OpenMPOptPass());
if (AttributorRun & AttributorRunOption::MODULE)
MPM.addPass(AttributorPass());
// Lower type metadata and the type.test intrinsic in the ThinLTO
// post link pipeline after ICP. This is to enable usage of the type
// tests in ICP sequences.
if (Phase == ThinOrFullLTOPhase::ThinLTOPostLink)
MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
invokePipelineEarlySimplificationEPCallbacks(MPM, Level);
// Interprocedural constant propagation now that basic cleanup has occurred
// and prior to optimizing globals.
// FIXME: This position in the pipeline hasn't been carefully considered in
// years, it should be re-analyzed.
MPM.addPass(IPSCCPPass(
IPSCCPOptions(/*AllowFuncSpec=*/
Level != OptimizationLevel::Os &&
Level != OptimizationLevel::Oz &&
!isLTOPreLink(Phase))));
// Attach metadata to indirect call sites indicating the set of functions
// they may target at run-time. This should follow IPSCCP.
MPM.addPass(CalledValuePropagationPass());
// Optimize globals to try and fold them into constants.
MPM.addPass(GlobalOptPass());
// Create a small function pass pipeline to cleanup after all the global
// optimizations.
FunctionPassManager GlobalCleanupPM;
// FIXME: Should this instead by a run of SROA?
GlobalCleanupPM.addPass(PromotePass());
GlobalCleanupPM.addPass(InstCombinePass());
invokePeepholeEPCallbacks(GlobalCleanupPM, Level);
GlobalCleanupPM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(GlobalCleanupPM),
PTO.EagerlyInvalidateAnalyses));
// We already asserted this happens in non-FullLTOPostLink earlier.
const bool IsPreLink = Phase != ThinOrFullLTOPhase::ThinLTOPostLink;
const bool IsPGOPreLink = PGOOpt && IsPreLink;
const bool IsPGOInstrGen =
IsPGOPreLink && PGOOpt->Action == PGOOptions::IRInstr;
const bool IsPGOInstrUse =
IsPGOPreLink && PGOOpt->Action == PGOOptions::IRUse;
const bool IsMemprofUse = IsPGOPreLink && !PGOOpt->MemoryProfile.empty();
// We don't want to mix pgo ctx gen and pgo gen; we also don't currently
// enable ctx profiling from the frontend.
assert(
!(IsPGOInstrGen && PGOCtxProfLoweringPass::isContextualIRPGOEnabled()) &&
"Enabling both instrumented FDO and contextual instrumentation is not "
"supported.");
// Enable contextual profiling instrumentation.
const bool IsCtxProfGen = !IsPGOInstrGen && IsPreLink &&
PGOCtxProfLoweringPass::isContextualIRPGOEnabled();
if (IsPGOInstrGen || IsPGOInstrUse || IsMemprofUse || IsCtxProfGen)
addPreInlinerPasses(MPM, Level, Phase);
// Add all the requested passes for instrumentation PGO, if requested.
if (IsPGOInstrGen || IsPGOInstrUse) {
addPGOInstrPasses(MPM, Level,
/*RunProfileGen=*/IsPGOInstrGen,
/*IsCS=*/false, PGOOpt->AtomicCounterUpdate,
PGOOpt->ProfileFile, PGOOpt->ProfileRemappingFile,
PGOOpt->FS);
} else if (IsCtxProfGen) {
MPM.addPass(PGOInstrumentationGen(false));
addPostPGOLoopRotation(MPM, Level);
MPM.addPass(PGOCtxProfLoweringPass());
}
if (IsPGOInstrGen || IsPGOInstrUse || IsCtxProfGen)
MPM.addPass(PGOIndirectCallPromotion(false, false));
if (IsPGOPreLink && PGOOpt->CSAction == PGOOptions::CSIRInstr)
MPM.addPass(PGOInstrumentationGenCreateVar(PGOOpt->CSProfileGenFile,
EnableSampledInstr));
if (IsMemprofUse)
MPM.addPass(MemProfUsePass(PGOOpt->MemoryProfile, PGOOpt->FS));
// Synthesize function entry counts for non-PGO compilation.
if (EnableSyntheticCounts && !PGOOpt)
MPM.addPass(SyntheticCountsPropagation());
if (EnablePGOForceFunctionAttrs && PGOOpt)
MPM.addPass(PGOForceFunctionAttrsPass(PGOOpt->ColdOptType));
MPM.addPass(AlwaysInlinerPass(/*InsertLifetimeIntrinsics=*/true));
if (EnableModuleInliner)
MPM.addPass(buildModuleInlinerPipeline(Level, Phase));
else
MPM.addPass(buildInlinerPipeline(Level, Phase));
// Remove any dead arguments exposed by cleanups, constant folding globals,
// and argument promotion.
MPM.addPass(DeadArgumentEliminationPass());
MPM.addPass(CoroCleanupPass());
// Optimize globals now that functions are fully simplified.
MPM.addPass(GlobalOptPass());
MPM.addPass(GlobalDCEPass());
return MPM;
}
/// TODO: Should LTO cause any differences to this set of passes?
void PassBuilder::addVectorPasses(OptimizationLevel Level,
FunctionPassManager &FPM, bool IsFullLTO) {
FPM.addPass(LoopVectorizePass(
LoopVectorizeOptions(!PTO.LoopInterleaving, !PTO.LoopVectorization)));
if (EnableInferAlignmentPass)
FPM.addPass(InferAlignmentPass());
if (IsFullLTO) {
// The vectorizer may have significantly shortened a loop body; unroll
// again. Unroll small loops to hide loop backedge latency and saturate any
// parallel execution resources of an out-of-order processor. We also then
// need to clean up redundancies and loop invariant code.
// FIXME: It would be really good to use a loop-integrated instruction
// combiner for cleanup here so that the unrolling and LICM can be pipelined
// across the loop nests.
// We do UnrollAndJam in a separate LPM to ensure it happens before unroll
if (EnableUnrollAndJam && PTO.LoopUnrolling)
FPM.addPass(createFunctionToLoopPassAdaptor(
LoopUnrollAndJamPass(Level.getSpeedupLevel())));
FPM.addPass(LoopUnrollPass(LoopUnrollOptions(
Level.getSpeedupLevel(), /*OnlyWhenForced=*/!PTO.LoopUnrolling,
PTO.ForgetAllSCEVInLoopUnroll)));
FPM.addPass(WarnMissedTransformationsPass());
// Now that we are done with loop unrolling, be it either by LoopVectorizer,
// or LoopUnroll passes, some variable-offset GEP's into alloca's could have
// become constant-offset, thus enabling SROA and alloca promotion. Do so.
// NOTE: we are very late in the pipeline, and we don't have any LICM
// or SimplifyCFG passes scheduled after us, that would cleanup
// the CFG mess this may created if allowed to modify CFG, so forbid that.
FPM.addPass(SROAPass(SROAOptions::PreserveCFG));
}
if (!IsFullLTO) {
// Eliminate loads by forwarding stores from the previous iteration to loads
// of the current iteration.
FPM.addPass(LoopLoadEliminationPass());
}
// Cleanup after the loop optimization passes.
FPM.addPass(InstCombinePass());
if (Level.getSpeedupLevel() > 1 && ExtraVectorizerPasses) {
ExtraVectorPassManager ExtraPasses;
// At higher optimization levels, try to clean up any runtime overlap and
// alignment checks inserted by the vectorizer. We want to track correlated
// runtime checks for two inner loops in the same outer loop, fold any
// common computations, hoist loop-invariant aspects out of any outer loop,
// and unswitch the runtime checks if possible. Once hoisted, we may have
// dead (or speculatable) control flows or more combining opportunities.
ExtraPasses.addPass(EarlyCSEPass());
ExtraPasses.addPass(CorrelatedValuePropagationPass());
ExtraPasses.addPass(InstCombinePass());
LoopPassManager LPM;
LPM.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/true));
LPM.addPass(SimpleLoopUnswitchPass(/* NonTrivial */ Level ==
OptimizationLevel::O3));
ExtraPasses.addPass(
createFunctionToLoopPassAdaptor(std::move(LPM), /*UseMemorySSA=*/true,
/*UseBlockFrequencyInfo=*/true));
ExtraPasses.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
ExtraPasses.addPass(InstCombinePass());
FPM.addPass(std::move(ExtraPasses));
}
// Now that we've formed fast to execute loop structures, we do further
// optimizations. These are run afterward as they might block doing complex
// analyses and transforms such as what are needed for loop vectorization.
// Cleanup after loop vectorization, etc. Simplification passes like CVP and
// GVN, loop transforms, and others have already run, so it's now better to
// convert to more optimized IR using more aggressive simplify CFG options.
// The extra sinking transform can create larger basic blocks, so do this
// before SLP vectorization.
FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions()
.forwardSwitchCondToPhi(true)
.convertSwitchRangeToICmp(true)
.convertSwitchToLookupTable(true)
.needCanonicalLoops(false)
.hoistCommonInsts(true)
.sinkCommonInsts(true)));
if (IsFullLTO) {
FPM.addPass(SCCPPass());
FPM.addPass(InstCombinePass());
FPM.addPass(BDCEPass());
}
// Optimize parallel scalar instruction chains into SIMD instructions.
if (PTO.SLPVectorization) {
FPM.addPass(SLPVectorizerPass());
if (Level.getSpeedupLevel() > 1 && ExtraVectorizerPasses) {
FPM.addPass(EarlyCSEPass());
}
}
// Enhance/cleanup vector code.
FPM.addPass(VectorCombinePass());
if (!IsFullLTO) {
FPM.addPass(InstCombinePass());
// Unroll small loops to hide loop backedge latency and saturate any
// parallel execution resources of an out-of-order processor. We also then
// need to clean up redundancies and loop invariant code.
// FIXME: It would be really good to use a loop-integrated instruction
// combiner for cleanup here so that the unrolling and LICM can be pipelined
// across the loop nests.
// We do UnrollAndJam in a separate LPM to ensure it happens before unroll
if (EnableUnrollAndJam && PTO.LoopUnrolling) {
FPM.addPass(createFunctionToLoopPassAdaptor(
LoopUnrollAndJamPass(Level.getSpeedupLevel())));
}
FPM.addPass(LoopUnrollPass(LoopUnrollOptions(
Level.getSpeedupLevel(), /*OnlyWhenForced=*/!PTO.LoopUnrolling,
PTO.ForgetAllSCEVInLoopUnroll)));
FPM.addPass(WarnMissedTransformationsPass());
// Now that we are done with loop unrolling, be it either by LoopVectorizer,
// or LoopUnroll passes, some variable-offset GEP's into alloca's could have
// become constant-offset, thus enabling SROA and alloca promotion. Do so.
// NOTE: we are very late in the pipeline, and we don't have any LICM
// or SimplifyCFG passes scheduled after us, that would cleanup
// the CFG mess this may created if allowed to modify CFG, so forbid that.
FPM.addPass(SROAPass(SROAOptions::PreserveCFG));
}
if (EnableInferAlignmentPass)
FPM.addPass(InferAlignmentPass());
FPM.addPass(InstCombinePass());
// This is needed for two reasons:
// 1. It works around problems that instcombine introduces, such as sinking
// expensive FP divides into loops containing multiplications using the
// divide result.
// 2. It helps to clean up some loop-invariant code created by the loop
// unroll pass when IsFullLTO=false.
FPM.addPass(createFunctionToLoopPassAdaptor(
LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/true),
/*UseMemorySSA=*/true, /*UseBlockFrequencyInfo=*/false));
// Now that we've vectorized and unrolled loops, we may have more refined
// alignment information, try to re-derive it here.
FPM.addPass(AlignmentFromAssumptionsPass());
}
ModulePassManager
PassBuilder::buildModuleOptimizationPipeline(OptimizationLevel Level,
ThinOrFullLTOPhase LTOPhase) {
const bool LTOPreLink = isLTOPreLink(LTOPhase);
ModulePassManager MPM;
// Run partial inlining pass to partially inline functions that have
// large bodies.
if (RunPartialInlining)
MPM.addPass(PartialInlinerPass());
// Remove avail extern fns and globals definitions since we aren't compiling
// an object file for later LTO. For LTO we want to preserve these so they
// are eligible for inlining at link-time. Note if they are unreferenced they
// will be removed by GlobalDCE later, so this only impacts referenced
// available externally globals. Eventually they will be suppressed during
// codegen, but eliminating here enables more opportunity for GlobalDCE as it
// may make globals referenced by available external functions dead and saves
// running remaining passes on the eliminated functions. These should be
// preserved during prelinking for link-time inlining decisions.
if (!LTOPreLink)
MPM.addPass(EliminateAvailableExternallyPass());
if (EnableOrderFileInstrumentation)
MPM.addPass(InstrOrderFilePass());
// Do RPO function attribute inference across the module to forward-propagate
// attributes where applicable.
// FIXME: Is this really an optimization rather than a canonicalization?
MPM.addPass(ReversePostOrderFunctionAttrsPass());
// Do a post inline PGO instrumentation and use pass. This is a context
// sensitive PGO pass. We don't want to do this in LTOPreLink phrase as
// cross-module inline has not been done yet. The context sensitive
// instrumentation is after all the inlines are done.
if (!LTOPreLink && PGOOpt) {
if (PGOOpt->CSAction == PGOOptions::CSIRInstr)
addPGOInstrPasses(MPM, Level, /*RunProfileGen=*/true,
/*IsCS=*/true, PGOOpt->AtomicCounterUpdate,
PGOOpt->CSProfileGenFile, PGOOpt->ProfileRemappingFile,
PGOOpt->FS);
else if (PGOOpt->CSAction == PGOOptions::CSIRUse)
addPGOInstrPasses(MPM, Level, /*RunProfileGen=*/false,
/*IsCS=*/true, PGOOpt->AtomicCounterUpdate,
PGOOpt->ProfileFile, PGOOpt->ProfileRemappingFile,
PGOOpt->FS);
}
// Re-compute GlobalsAA here prior to function passes. This is particularly
// useful as the above will have inlined, DCE'ed, and function-attr
// propagated everything. We should at this point have a reasonably minimal
// and richly annotated call graph. By computing aliasing and mod/ref
// information for all local globals here, the late loop passes and notably
// the vectorizer will be able to use them to help recognize vectorizable
// memory operations.
if (EnableGlobalAnalyses)
MPM.addPass(RecomputeGlobalsAAPass());
invokeOptimizerEarlyEPCallbacks(MPM, Level);
FunctionPassManager OptimizePM;
// Scheduling LoopVersioningLICM when inlining is over, because after that
// we may see more accurate aliasing. Reason to run this late is that too
// early versioning may prevent further inlining due to increase of code
// size. Other optimizations which runs later might get benefit of no-alias
// assumption in clone loop.
if (UseLoopVersioningLICM) {
OptimizePM.addPass(
createFunctionToLoopPassAdaptor(LoopVersioningLICMPass()));
// LoopVersioningLICM pass might increase new LICM opportunities.
OptimizePM.addPass(createFunctionToLoopPassAdaptor(
LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/true),
/*USeMemorySSA=*/true, /*UseBlockFrequencyInfo=*/false));
}
OptimizePM.addPass(Float2IntPass());
OptimizePM.addPass(LowerConstantIntrinsicsPass());
if (EnableMatrix) {
OptimizePM.addPass(LowerMatrixIntrinsicsPass());
OptimizePM.addPass(EarlyCSEPass());
}
// CHR pass should only be applied with the profile information.
// The check is to check the profile summary information in CHR.
if (EnableCHR && Level == OptimizationLevel::O3)
OptimizePM.addPass(ControlHeightReductionPass());
// FIXME: We need to run some loop optimizations to re-rotate loops after
// simplifycfg and others undo their rotation.
// Optimize the loop execution. These passes operate on entire loop nests
// rather than on each loop in an inside-out manner, and so they are actually
// function passes.
invokeVectorizerStartEPCallbacks(OptimizePM, Level);
LoopPassManager LPM;
// First rotate loops that may have been un-rotated by prior passes.
// Disable header duplication at -Oz.
LPM.addPass(LoopRotatePass(EnableLoopHeaderDuplication ||
Level != OptimizationLevel::Oz,
LTOPreLink));
// Some loops may have become dead by now. Try to delete them.
// FIXME: see discussion in https://reviews.llvm.org/D112851,
// this may need to be revisited once we run GVN before loop deletion
// in the simplification pipeline.
LPM.addPass(LoopDeletionPass());
OptimizePM.addPass(createFunctionToLoopPassAdaptor(
std::move(LPM), /*UseMemorySSA=*/false, /*UseBlockFrequencyInfo=*/false));
// Distribute loops to allow partial vectorization. I.e. isolate dependences
// into separate loop that would otherwise inhibit vectorization. This is
// currently only performed for loops marked with the metadata
// llvm.loop.distribute=true or when -enable-loop-distribute is specified.
OptimizePM.addPass(LoopDistributePass());
// Populates the VFABI attribute with the scalar-to-vector mappings
// from the TargetLibraryInfo.
OptimizePM.addPass(InjectTLIMappings());
addVectorPasses(Level, OptimizePM, /* IsFullLTO */ false);
// LoopSink pass sinks instructions hoisted by LICM, which serves as a
// canonicalization pass that enables other optimizations. As a result,
// LoopSink pass needs to be a very late IR pass to avoid undoing LICM
// result too early.
OptimizePM.addPass(LoopSinkPass());
// And finally clean up LCSSA form before generating code.
OptimizePM.addPass(InstSimplifyPass());
// This hoists/decomposes div/rem ops. It should run after other sink/hoist
// passes to avoid re-sinking, but before SimplifyCFG because it can allow
// flattening of blocks.
OptimizePM.addPass(DivRemPairsPass());
// Try to annotate calls that were created during optimization.
OptimizePM.addPass(TailCallElimPass());
// LoopSink (and other loop passes since the last simplifyCFG) might have
// resulted in single-entry-single-exit or empty blocks. Clean up the CFG.
OptimizePM.addPass(
SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
// Add the core optimizing pipeline.
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(OptimizePM),
PTO.EagerlyInvalidateAnalyses));
invokeOptimizerLastEPCallbacks(MPM, Level);
// Split out cold code. Splitting is done late to avoid hiding context from
// other optimizations and inadvertently regressing performance. The tradeoff
// is that this has a higher code size cost than splitting early.
if (EnableHotColdSplit && !LTOPreLink)
MPM.addPass(HotColdSplittingPass());
// Search the code for similar regions of code. If enough similar regions can
// be found where extracting the regions into their own function will decrease
// the size of the program, we extract the regions, a deduplicate the
// structurally similar regions.
if (EnableIROutliner)
MPM.addPass(IROutlinerPass());
// Now we need to do some global optimization transforms.
// FIXME: It would seem like these should come first in the optimization
// pipeline and maybe be the bottom of the canonicalization pipeline? Weird
// ordering here.
MPM.addPass(GlobalDCEPass());
MPM.addPass(ConstantMergePass());
// Merge functions if requested. It has a better chance to merge functions
// after ConstantMerge folded jump tables.
if (PTO.MergeFunctions)
MPM.addPass(MergeFunctionsPass());
if (PTO.CallGraphProfile && !LTOPreLink)
MPM.addPass(CGProfilePass(LTOPhase == ThinOrFullLTOPhase::FullLTOPostLink ||
LTOPhase == ThinOrFullLTOPhase::ThinLTOPostLink));
// TODO: Relative look table converter pass caused an issue when full lto is
// enabled. See https://reviews.llvm.org/D94355 for more details.
// Until the issue fixed, disable this pass during pre-linking phase.
if (!LTOPreLink)
MPM.addPass(RelLookupTableConverterPass());
return MPM;
}
ModulePassManager
PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
bool LTOPreLink) {
if (Level == OptimizationLevel::O0)
return buildO0DefaultPipeline(Level, LTOPreLink);
ModulePassManager MPM;
// Convert @llvm.global.annotations to !annotation metadata.
MPM.addPass(Annotation2MetadataPass());
// Force any function attributes we want the rest of the pipeline to observe.
MPM.addPass(ForceFunctionAttrsPass());
if (PGOOpt && PGOOpt->DebugInfoForProfiling)
MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
// Apply module pipeline start EP callback.
invokePipelineStartEPCallbacks(MPM, Level);
const ThinOrFullLTOPhase LTOPhase = LTOPreLink
? ThinOrFullLTOPhase::FullLTOPreLink
: ThinOrFullLTOPhase::None;
// Add the core simplification pipeline.
MPM.addPass(buildModuleSimplificationPipeline(Level, LTOPhase));
// Now add the optimization pipeline.
MPM.addPass(buildModuleOptimizationPipeline(Level, LTOPhase));
if (PGOOpt && PGOOpt->PseudoProbeForProfiling &&
PGOOpt->Action == PGOOptions::SampleUse)
MPM.addPass(PseudoProbeUpdatePass());
// Emit annotation remarks.
addAnnotationRemarksPass(MPM);
if (LTOPreLink)
addRequiredLTOPreLinkPasses(MPM);
return MPM;
}
ModulePassManager
PassBuilder::buildFatLTODefaultPipeline(OptimizationLevel Level, bool ThinLTO,
bool EmitSummary) {
ModulePassManager MPM;
if (ThinLTO)
MPM.addPass(buildThinLTOPreLinkDefaultPipeline(Level));
else
MPM.addPass(buildLTOPreLinkDefaultPipeline(Level));
MPM.addPass(EmbedBitcodePass(ThinLTO, EmitSummary));
// Use the ThinLTO post-link pipeline with sample profiling
if (ThinLTO && PGOOpt && PGOOpt->Action == PGOOptions::SampleUse)
MPM.addPass(buildThinLTODefaultPipeline(Level, /*ImportSummary=*/nullptr));
else {
// otherwise, just use module optimization
MPM.addPass(
buildModuleOptimizationPipeline(Level, ThinOrFullLTOPhase::None));
// Emit annotation remarks.
addAnnotationRemarksPass(MPM);
}
return MPM;
}
ModulePassManager
PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level) {
if (Level == OptimizationLevel::O0)
return buildO0DefaultPipeline(Level, /*LTOPreLink*/true);
ModulePassManager MPM;
// Convert @llvm.global.annotations to !annotation metadata.
MPM.addPass(Annotation2MetadataPass());
// Force any function attributes we want the rest of the pipeline to observe.
MPM.addPass(ForceFunctionAttrsPass());
if (PGOOpt && PGOOpt->DebugInfoForProfiling)
MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
// Apply module pipeline start EP callback.
invokePipelineStartEPCallbacks(MPM, Level);
// If we are planning to perform ThinLTO later, we don't bloat the code with
// unrolling/vectorization/... now. Just simplify the module as much as we
// can.
MPM.addPass(buildModuleSimplificationPipeline(
Level, ThinOrFullLTOPhase::ThinLTOPreLink));
// Run partial inlining pass to partially inline functions that have
// large bodies.
// FIXME: It isn't clear whether this is really the right place to run this
// in ThinLTO. Because there is another canonicalization and simplification
// phase that will run after the thin link, running this here ends up with
// less information than will be available later and it may grow functions in
// ways that aren't beneficial.
if (RunPartialInlining)
MPM.addPass(PartialInlinerPass());
if (PGOOpt && PGOOpt->PseudoProbeForProfiling &&
PGOOpt->Action == PGOOptions::SampleUse)
MPM.addPass(PseudoProbeUpdatePass());
// Handle Optimizer{Early,Last}EPCallbacks added by clang on PreLink. Actual
// optimization is going to be done in PostLink stage, but clang can't add
// callbacks there in case of in-process ThinLTO called by linker.
invokeOptimizerEarlyEPCallbacks(MPM, Level);
invokeOptimizerLastEPCallbacks(MPM, Level);
// Emit annotation remarks.
addAnnotationRemarksPass(MPM);
addRequiredLTOPreLinkPasses(MPM);
return MPM;
}
ModulePassManager PassBuilder::buildThinLTODefaultPipeline(
OptimizationLevel Level, const ModuleSummaryIndex *ImportSummary) {
ModulePassManager MPM;
if (ImportSummary) {
// For ThinLTO we must apply the context disambiguation decisions early, to
// ensure we can correctly match the callsites to summary data.
if (EnableMemProfContextDisambiguation)
MPM.addPass(MemProfContextDisambiguation(ImportSummary));
// These passes import type identifier resolutions for whole-program
// devirtualization and CFI. They must run early because other passes may
// disturb the specific instruction patterns that these passes look for,
// creating dependencies on resolutions that may not appear in the summary.
//
// For example, GVN may transform the pattern assume(type.test) appearing in
// two basic blocks into assume(phi(type.test, type.test)), which would
// transform a dependency on a WPD resolution into a dependency on a type
// identifier resolution for CFI.
//
// Also, WPD has access to more precise information than ICP and can
// devirtualize more effectively, so it should operate on the IR first.
//
// The WPD and LowerTypeTest passes need to run at -O0 to lower type
// metadata and intrinsics.
MPM.addPass(WholeProgramDevirtPass(nullptr, ImportSummary));
MPM.addPass(LowerTypeTestsPass(nullptr, ImportSummary));
}
if (Level == OptimizationLevel::O0) {
// Run a second time to clean up any type tests left behind by WPD for use
// in ICP.
MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
// Drop available_externally and unreferenced globals. This is necessary
// with ThinLTO in order to avoid leaving undefined references to dead
// globals in the object file.
MPM.addPass(EliminateAvailableExternallyPass());
MPM.addPass(GlobalDCEPass());
return MPM;
}
// Add the core simplification pipeline.
MPM.addPass(buildModuleSimplificationPipeline(
Level, ThinOrFullLTOPhase::ThinLTOPostLink));
// Now add the optimization pipeline.
MPM.addPass(buildModuleOptimizationPipeline(
Level, ThinOrFullLTOPhase::ThinLTOPostLink));
// Emit annotation remarks.
addAnnotationRemarksPass(MPM);
return MPM;
}
ModulePassManager
PassBuilder::buildLTOPreLinkDefaultPipeline(OptimizationLevel Level) {
// FIXME: We should use a customized pre-link pipeline!
return buildPerModuleDefaultPipeline(Level,
/* LTOPreLink */ true);
}
ModulePassManager
PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
ModuleSummaryIndex *ExportSummary) {
ModulePassManager MPM;
invokeFullLinkTimeOptimizationEarlyEPCallbacks(MPM, Level);
// Create a function that performs CFI checks for cross-DSO calls with targets
// in the current module.
MPM.addPass(CrossDSOCFIPass());
if (Level == OptimizationLevel::O0) {
// The WPD and LowerTypeTest passes need to run at -O0 to lower type
// metadata and intrinsics.
MPM.addPass(WholeProgramDevirtPass(ExportSummary, nullptr));
MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
// Run a second time to clean up any type tests left behind by WPD for use
// in ICP.
MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
invokeFullLinkTimeOptimizationLastEPCallbacks(MPM, Level);
// Emit annotation remarks.
addAnnotationRemarksPass(MPM);
return MPM;
}
if (PGOOpt && PGOOpt->Action == PGOOptions::SampleUse) {
// Load sample profile before running the LTO optimization pipeline.
MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
PGOOpt->ProfileRemappingFile,
ThinOrFullLTOPhase::FullLTOPostLink));
// Cache ProfileSummaryAnalysis once to avoid the potential need to insert
// RequireAnalysisPass for PSI before subsequent non-module passes.
MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
}
// Try to run OpenMP optimizations, quick no-op if no OpenMP metadata present.
MPM.addPass(OpenMPOptPass(ThinOrFullLTOPhase::FullLTOPostLink));
// Remove unused virtual tables to improve the quality of code generated by
// whole-program devirtualization and bitset lowering.
MPM.addPass(GlobalDCEPass(/*InLTOPostLink=*/true));
// Do basic inference of function attributes from known properties of system
// libraries and other oracles.
MPM.addPass(InferFunctionAttrsPass());
if (Level.getSpeedupLevel() > 1) {
MPM.addPass(createModuleToFunctionPassAdaptor(
CallSiteSplittingPass(), PTO.EagerlyInvalidateAnalyses));
// Indirect call promotion. This should promote all the targets that are
// left by the earlier promotion pass that promotes intra-module targets.
// This two-step promotion is to save the compile time. For LTO, it should
// produce the same result as if we only do promotion here.
MPM.addPass(PGOIndirectCallPromotion(
true /* InLTO */, PGOOpt && PGOOpt->Action == PGOOptions::SampleUse));
// Propagate constants at call sites into the functions they call. This
// opens opportunities for globalopt (and inlining) by substituting function
// pointers passed as arguments to direct uses of functions.
MPM.addPass(IPSCCPPass(IPSCCPOptions(/*AllowFuncSpec=*/
Level != OptimizationLevel::Os &&
Level != OptimizationLevel::Oz)));
// Attach metadata to indirect call sites indicating the set of functions
// they may target at run-time. This should follow IPSCCP.
MPM.addPass(CalledValuePropagationPass());
}
// Now deduce any function attributes based in the current code.
MPM.addPass(
createModuleToPostOrderCGSCCPassAdaptor(PostOrderFunctionAttrsPass()));
// Do RPO function attribute inference across the module to forward-propagate
// attributes where applicable.
// FIXME: Is this really an optimization rather than a canonicalization?
MPM.addPass(ReversePostOrderFunctionAttrsPass());
// Use in-range annotations on GEP indices to split globals where beneficial.
MPM.addPass(GlobalSplitPass());
// Run whole program optimization of virtual call when the list of callees
// is fixed.
MPM.addPass(WholeProgramDevirtPass(ExportSummary, nullptr));
// Stop here at -O1.
if (Level == OptimizationLevel::O1) {
// The LowerTypeTestsPass needs to run to lower type metadata and the
// type.test intrinsics. The pass does nothing if CFI is disabled.
MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
// Run a second time to clean up any type tests left behind by WPD for use
// in ICP (which is performed earlier than this in the regular LTO
// pipeline).
MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
invokeFullLinkTimeOptimizationLastEPCallbacks(MPM, Level);
// Emit annotation remarks.
addAnnotationRemarksPass(MPM);
return MPM;
}
// Optimize globals to try and fold them into constants.
MPM.addPass(GlobalOptPass());
// Promote any localized globals to SSA registers.
MPM.addPass(createModuleToFunctionPassAdaptor(PromotePass()));
// Linking modules together can lead to duplicate global constant, only
// keep one copy of each constant.
MPM.addPass(ConstantMergePass());
// Remove unused arguments from functions.
MPM.addPass(DeadArgumentEliminationPass());
// Reduce the code after globalopt and ipsccp. Both can open up significant
// simplification opportunities, and both can propagate functions through
// function pointers. When this happens, we often have to resolve varargs
// calls, etc, so let instcombine do this.
FunctionPassManager PeepholeFPM;
PeepholeFPM.addPass(InstCombinePass());
if (Level.getSpeedupLevel() > 1)
PeepholeFPM.addPass(AggressiveInstCombinePass());
invokePeepholeEPCallbacks(PeepholeFPM, Level);
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(PeepholeFPM),
PTO.EagerlyInvalidateAnalyses));
// Note: historically, the PruneEH pass was run first to deduce nounwind and
// generally clean up exception handling overhead. It isn't clear this is
// valuable as the inliner doesn't currently care whether it is inlining an
// invoke or a call.
// Run the inliner now.
if (EnableModuleInliner) {
MPM.addPass(ModuleInlinerPass(getInlineParamsFromOptLevel(Level),
UseInlineAdvisor,
ThinOrFullLTOPhase::FullLTOPostLink));
} else {
MPM.addPass(ModuleInlinerWrapperPass(
getInlineParamsFromOptLevel(Level),
/* MandatoryFirst */ true,
InlineContext{ThinOrFullLTOPhase::FullLTOPostLink,
InlinePass::CGSCCInliner}));
}
// Perform context disambiguation after inlining, since that would reduce the
// amount of additional cloning required to distinguish the allocation
// contexts.
if (EnableMemProfContextDisambiguation)
MPM.addPass(MemProfContextDisambiguation());
// Optimize globals again after we ran the inliner.
MPM.addPass(GlobalOptPass());
// Run the OpenMPOpt pass again after global optimizations.
MPM.addPass(OpenMPOptPass(ThinOrFullLTOPhase::FullLTOPostLink));
// Garbage collect dead functions.
MPM.addPass(GlobalDCEPass(/*InLTOPostLink=*/true));
// If we didn't decide to inline a function, check to see if we can
// transform it to pass arguments by value instead of by reference.
MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(ArgumentPromotionPass()));
FunctionPassManager FPM;
// The IPO Passes may leave cruft around. Clean up after them.
FPM.addPass(InstCombinePass());
invokePeepholeEPCallbacks(FPM, Level);
if (EnableConstraintElimination)
FPM.addPass(ConstraintEliminationPass());
FPM.addPass(JumpThreadingPass());
// Do a post inline PGO instrumentation and use pass. This is a context
// sensitive PGO pass.
if (PGOOpt) {
if (PGOOpt->CSAction == PGOOptions::CSIRInstr)
addPGOInstrPasses(MPM, Level, /*RunProfileGen=*/true,
/*IsCS=*/true, PGOOpt->AtomicCounterUpdate,
PGOOpt->CSProfileGenFile, PGOOpt->ProfileRemappingFile,
PGOOpt->FS);
else if (PGOOpt->CSAction == PGOOptions::CSIRUse)
addPGOInstrPasses(MPM, Level, /*RunProfileGen=*/false,
/*IsCS=*/true, PGOOpt->AtomicCounterUpdate,
PGOOpt->ProfileFile, PGOOpt->ProfileRemappingFile,
PGOOpt->FS);
}
// Break up allocas
FPM.addPass(SROAPass(SROAOptions::ModifyCFG));
// LTO provides additional opportunities for tailcall elimination due to
// link-time inlining, and visibility of nocapture attribute.
FPM.addPass(TailCallElimPass());
// Run a few AA driver optimizations here and now to cleanup the code.
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM),
PTO.EagerlyInvalidateAnalyses));
MPM.addPass(
createModuleToPostOrderCGSCCPassAdaptor(PostOrderFunctionAttrsPass()));
// Require the GlobalsAA analysis for the module so we can query it within
// MainFPM.
if (EnableGlobalAnalyses) {
MPM.addPass(RequireAnalysisPass<GlobalsAA, Module>());
// Invalidate AAManager so it can be recreated and pick up the newly
// available GlobalsAA.
MPM.addPass(
createModuleToFunctionPassAdaptor(InvalidateAnalysisPass<AAManager>()));
}
FunctionPassManager MainFPM;
MainFPM.addPass(createFunctionToLoopPassAdaptor(
LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
/*AllowSpeculation=*/true),
/*USeMemorySSA=*/true, /*UseBlockFrequencyInfo=*/false));
if (RunNewGVN)
MainFPM.addPass(NewGVNPass());
else
MainFPM.addPass(GVNPass());
// Remove dead memcpy()'s.
MainFPM.addPass(MemCpyOptPass());
// Nuke dead stores.
MainFPM.addPass(DSEPass());
MainFPM.addPass(MoveAutoInitPass());
MainFPM.addPass(MergedLoadStoreMotionPass());
LoopPassManager LPM;
if (EnableLoopFlatten && Level.getSpeedupLevel() > 1)
LPM.addPass(LoopFlattenPass());
LPM.addPass(IndVarSimplifyPass());
LPM.addPass(LoopDeletionPass());
// FIXME: Add loop interchange.
// Unroll small loops and perform peeling.
LPM.addPass(LoopFullUnrollPass(Level.getSpeedupLevel(),
/* OnlyWhenForced= */ !PTO.LoopUnrolling,
PTO.ForgetAllSCEVInLoopUnroll));
// The loop passes in LPM (LoopFullUnrollPass) do not preserve MemorySSA.
// *All* loop passes must preserve it, in order to be able to use it.
MainFPM.addPass(createFunctionToLoopPassAdaptor(
std::move(LPM), /*UseMemorySSA=*/false, /*UseBlockFrequencyInfo=*/true));
MainFPM.addPass(LoopDistributePass());
addVectorPasses(Level, MainFPM, /* IsFullLTO */ true);
// Run the OpenMPOpt CGSCC pass again late.
MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
OpenMPOptCGSCCPass(ThinOrFullLTOPhase::FullLTOPostLink)));
invokePeepholeEPCallbacks(MainFPM, Level);
MainFPM.addPass(JumpThreadingPass());
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(MainFPM),
PTO.EagerlyInvalidateAnalyses));
// Lower type metadata and the type.test intrinsic. This pass supports
// clang's control flow integrity mechanisms (-fsanitize=cfi*) and needs
// to be run at link time if CFI is enabled. This pass does nothing if
// CFI is disabled.
MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
// Run a second time to clean up any type tests left behind by WPD for use
// in ICP (which is performed earlier than this in the regular LTO pipeline).
MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
// Enable splitting late in the FullLTO post-link pipeline.
if (EnableHotColdSplit)
MPM.addPass(HotColdSplittingPass());
// Add late LTO optimization passes.
FunctionPassManager LateFPM;
// LoopSink pass sinks instructions hoisted by LICM, which serves as a
// canonicalization pass that enables other optimizations. As a result,
// LoopSink pass needs to be a very late IR pass to avoid undoing LICM
// result too early.
LateFPM.addPass(LoopSinkPass());
// This hoists/decomposes div/rem ops. It should run after other sink/hoist
// passes to avoid re-sinking, but before SimplifyCFG because it can allow
// flattening of blocks.
LateFPM.addPass(DivRemPairsPass());
// Delete basic blocks, which optimization passes may have killed.
LateFPM.addPass(SimplifyCFGPass(
SimplifyCFGOptions().convertSwitchRangeToICmp(true).hoistCommonInsts(
true)));
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(LateFPM)));
// Drop bodies of available eternally objects to improve GlobalDCE.
MPM.addPass(EliminateAvailableExternallyPass());
// Now that we have optimized the program, discard unreachable functions.
MPM.addPass(GlobalDCEPass(/*InLTOPostLink=*/true));
if (PTO.MergeFunctions)
MPM.addPass(MergeFunctionsPass());
if (PTO.CallGraphProfile)
MPM.addPass(CGProfilePass(/*InLTOPostLink=*/true));
invokeFullLinkTimeOptimizationLastEPCallbacks(MPM, Level);
// Emit annotation remarks.
addAnnotationRemarksPass(MPM);
return MPM;
}
ModulePassManager PassBuilder::buildO0DefaultPipeline(OptimizationLevel Level,
bool LTOPreLink) {
assert(Level == OptimizationLevel::O0 &&
"buildO0DefaultPipeline should only be used with O0");
ModulePassManager MPM;
// Perform pseudo probe instrumentation in O0 mode. This is for the
// consistency between different build modes. For example, a LTO build can be
// mixed with an O0 prelink and an O2 postlink. Loading a sample profile in
// the postlink will require pseudo probe instrumentation in the prelink.
if (PGOOpt && PGOOpt->PseudoProbeForProfiling)
MPM.addPass(SampleProfileProbePass(TM));
if (PGOOpt && (PGOOpt->Action == PGOOptions::IRInstr ||
PGOOpt->Action == PGOOptions::IRUse))
addPGOInstrPassesForO0(
MPM,
/*RunProfileGen=*/(PGOOpt->Action == PGOOptions::IRInstr),
/*IsCS=*/false, PGOOpt->AtomicCounterUpdate, PGOOpt->ProfileFile,
PGOOpt->ProfileRemappingFile, PGOOpt->FS);
// Instrument function entry and exit before all inlining.
MPM.addPass(createModuleToFunctionPassAdaptor(
EntryExitInstrumenterPass(/*PostInlining=*/false)));
invokePipelineStartEPCallbacks(MPM, Level);
if (PGOOpt && PGOOpt->DebugInfoForProfiling)
MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
invokePipelineEarlySimplificationEPCallbacks(MPM, Level);
// Build a minimal pipeline based on the semantics required by LLVM,
// which is just that always inlining occurs. Further, disable generating
// lifetime intrinsics to avoid enabling further optimizations during
// code generation.
MPM.addPass(AlwaysInlinerPass(
/*InsertLifetimeIntrinsics=*/false));
if (PTO.MergeFunctions)
MPM.addPass(MergeFunctionsPass());
if (EnableMatrix)
MPM.addPass(
createModuleToFunctionPassAdaptor(LowerMatrixIntrinsicsPass(true)));
if (!CGSCCOptimizerLateEPCallbacks.empty()) {
CGSCCPassManager CGPM;
invokeCGSCCOptimizerLateEPCallbacks(CGPM, Level);
if (!CGPM.isEmpty())
MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPM)));
}
if (!LateLoopOptimizationsEPCallbacks.empty()) {
LoopPassManager LPM;
invokeLateLoopOptimizationsEPCallbacks(LPM, Level);
if (!LPM.isEmpty()) {
MPM.addPass(createModuleToFunctionPassAdaptor(
createFunctionToLoopPassAdaptor(std::move(LPM))));
}
}
if (!LoopOptimizerEndEPCallbacks.empty()) {
LoopPassManager LPM;
invokeLoopOptimizerEndEPCallbacks(LPM, Level);
if (!LPM.isEmpty()) {
MPM.addPass(createModuleToFunctionPassAdaptor(
createFunctionToLoopPassAdaptor(std::move(LPM))));
}
}
if (!ScalarOptimizerLateEPCallbacks.empty()) {
FunctionPassManager FPM;
invokeScalarOptimizerLateEPCallbacks(FPM, Level);
if (!FPM.isEmpty())
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
}
invokeOptimizerEarlyEPCallbacks(MPM, Level);
if (!VectorizerStartEPCallbacks.empty()) {
FunctionPassManager FPM;
invokeVectorizerStartEPCallbacks(FPM, Level);
if (!FPM.isEmpty())
MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
}
ModulePassManager CoroPM;
CoroPM.addPass(CoroEarlyPass());
CGSCCPassManager CGPM;
CGPM.addPass(CoroSplitPass());
CoroPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPM)));
CoroPM.addPass(CoroCleanupPass());
CoroPM.addPass(GlobalDCEPass());
MPM.addPass(CoroConditionalWrapper(std::move(CoroPM)));
invokeOptimizerLastEPCallbacks(MPM, Level);
if (LTOPreLink)
addRequiredLTOPreLinkPasses(MPM);
MPM.addPass(createModuleToFunctionPassAdaptor(AnnotationRemarksPass()));
return MPM;
}
AAManager PassBuilder::buildDefaultAAPipeline() {
AAManager AA;
// The order in which these are registered determines their priority when
// being queried.
// First we register the basic alias analysis that provides the majority of
// per-function local AA logic. This is a stateless, on-demand local set of
// AA techniques.
AA.registerFunctionAnalysis<BasicAA>();
// Next we query fast, specialized alias analyses that wrap IR-embedded
// information about aliasing.
AA.registerFunctionAnalysis<ScopedNoAliasAA>();
AA.registerFunctionAnalysis<TypeBasedAA>();
// Add support for querying global aliasing information when available.
// Because the `AAManager` is a function analysis and `GlobalsAA` is a module
// analysis, all that the `AAManager` can do is query for any *cached*
// results from `GlobalsAA` through a readonly proxy.
if (EnableGlobalAnalyses)
AA.registerModuleAnalysis<GlobalsAA>();
// Add target-specific alias analyses.
if (TM)
TM->registerDefaultAliasAnalyses(AA);
return AA;
}