/
PassManagerBuilder.cpp
1326 lines (1106 loc) · 53.1 KB
/
PassManagerBuilder.cpp
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//===- PassManagerBuilder.cpp - Build Standard Pass -----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines the PassManagerBuilder class, which is used to set up a
// "standard" optimization sequence suitable for languages like C and C++.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#include "llvm-c/Transforms/PassManagerBuilder.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/CFLAndersAliasAnalysis.h"
#include "llvm/Analysis/CFLSteensAliasAnalysis.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/ScopedNoAliasAA.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TypeBasedAliasAnalysis.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Verifier.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Target/CGPassBuilderOption.h"
#include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/Attributor.h"
#include "llvm/Transforms/IPO/ForceFunctionAttrs.h"
#include "llvm/Transforms/IPO/FunctionAttrs.h"
#include "llvm/Transforms/IPO/InferFunctionAttrs.h"
#include "llvm/Transforms/InstCombine/InstCombine.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Scalar/GVN.h"
#include "llvm/Transforms/Scalar/InstSimplifyPass.h"
#include "llvm/Transforms/Scalar/LICM.h"
#include "llvm/Transforms/Scalar/LoopUnrollPass.h"
#include "llvm/Transforms/Scalar/SCCP.h"
#include "llvm/Transforms/Scalar/SimpleLoopUnswitch.h"
#include "llvm/Transforms/Utils.h"
#include "llvm/Transforms/Vectorize.h"
#include "llvm/Transforms/Vectorize/LoopVectorize.h"
#include "llvm/Transforms/Vectorize/SLPVectorizer.h"
#include "llvm/Transforms/Vectorize/VectorCombine.h"
using namespace llvm;
namespace llvm {
cl::opt<bool> RunPartialInlining("enable-partial-inlining", cl::init(false),
cl::Hidden, cl::ZeroOrMore,
cl::desc("Run Partial inlinining pass"));
static cl::opt<bool>
UseGVNAfterVectorization("use-gvn-after-vectorization",
cl::init(false), cl::Hidden,
cl::desc("Run GVN instead of Early CSE after vectorization passes"));
cl::opt<bool> ExtraVectorizerPasses(
"extra-vectorizer-passes", cl::init(false), cl::Hidden,
cl::desc("Run cleanup optimization passes after vectorization."));
static cl::opt<bool>
RunLoopRerolling("reroll-loops", cl::Hidden,
cl::desc("Run the loop rerolling pass"));
cl::opt<bool> RunNewGVN("enable-newgvn", cl::init(false), cl::Hidden,
cl::desc("Run the NewGVN pass"));
// Experimental option to use CFL-AA
static cl::opt<::CFLAAType>
UseCFLAA("use-cfl-aa", cl::init(::CFLAAType::None), cl::Hidden,
cl::desc("Enable the new, experimental CFL alias analysis"),
cl::values(clEnumValN(::CFLAAType::None, "none", "Disable CFL-AA"),
clEnumValN(::CFLAAType::Steensgaard, "steens",
"Enable unification-based CFL-AA"),
clEnumValN(::CFLAAType::Andersen, "anders",
"Enable inclusion-based CFL-AA"),
clEnumValN(::CFLAAType::Both, "both",
"Enable both variants of CFL-AA")));
cl::opt<bool> EnableLoopInterchange(
"enable-loopinterchange", cl::init(false), cl::Hidden,
cl::desc("Enable the experimental LoopInterchange Pass"));
cl::opt<bool> EnableUnrollAndJam("enable-unroll-and-jam", cl::init(false),
cl::Hidden,
cl::desc("Enable Unroll And Jam Pass"));
cl::opt<bool> EnableLoopFlatten("enable-loop-flatten", cl::init(false),
cl::Hidden,
cl::desc("Enable the LoopFlatten Pass"));
cl::opt<bool> EnableDFAJumpThreading("enable-dfa-jump-thread",
cl::desc("Enable DFA jump threading."),
cl::init(false), cl::Hidden);
static cl::opt<bool>
EnablePrepareForThinLTO("prepare-for-thinlto", cl::init(false), cl::Hidden,
cl::desc("Enable preparation for ThinLTO."));
static cl::opt<bool>
EnablePerformThinLTO("perform-thinlto", cl::init(false), cl::Hidden,
cl::desc("Enable performing ThinLTO."));
cl::opt<bool> EnableHotColdSplit("hot-cold-split", cl::init(false),
cl::ZeroOrMore, cl::desc("Enable hot-cold splitting pass"));
cl::opt<bool> EnableIROutliner("ir-outliner", cl::init(false), cl::Hidden,
cl::desc("Enable ir outliner pass"));
static cl::opt<bool> UseLoopVersioningLICM(
"enable-loop-versioning-licm", cl::init(false), cl::Hidden,
cl::desc("Enable the experimental Loop Versioning LICM pass"));
cl::opt<bool>
DisablePreInliner("disable-preinline", cl::init(false), cl::Hidden,
cl::desc("Disable pre-instrumentation inliner"));
cl::opt<int> PreInlineThreshold(
"preinline-threshold", cl::Hidden, cl::init(75), cl::ZeroOrMore,
cl::desc("Control the amount of inlining in pre-instrumentation inliner "
"(default = 75)"));
cl::opt<bool>
EnableGVNHoist("enable-gvn-hoist", cl::init(false), cl::ZeroOrMore,
cl::desc("Enable the GVN hoisting pass (default = off)"));
static cl::opt<bool>
DisableLibCallsShrinkWrap("disable-libcalls-shrinkwrap", cl::init(false),
cl::Hidden,
cl::desc("Disable shrink-wrap library calls"));
static cl::opt<bool> EnableSimpleLoopUnswitch(
"enable-simple-loop-unswitch", cl::init(false), cl::Hidden,
cl::desc("Enable the simple loop unswitch pass. Also enables independent "
"cleanup passes integrated into the loop pass manager pipeline."));
cl::opt<bool>
EnableGVNSink("enable-gvn-sink", cl::init(false), cl::ZeroOrMore,
cl::desc("Enable the GVN sinking pass (default = off)"));
// This option is used in simplifying testing SampleFDO optimizations for
// profile loading.
cl::opt<bool>
EnableCHR("enable-chr", cl::init(true), cl::Hidden,
cl::desc("Enable control height reduction optimization (CHR)"));
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. "));
cl::opt<bool> EnableOrderFileInstrumentation(
"enable-order-file-instrumentation", cl::init(false), cl::Hidden,
cl::desc("Enable order file instrumentation (default = off)"));
cl::opt<bool> EnableMatrix(
"enable-matrix", cl::init(false), cl::Hidden,
cl::desc("Enable lowering of the matrix intrinsics"));
cl::opt<bool> EnableConstraintElimination(
"enable-constraint-elimination", cl::init(false), cl::Hidden,
cl::desc(
"Enable pass to eliminate conditions based on linear constraints."));
cl::opt<bool> EnableFunctionSpecialization(
"enable-function-specialization", cl::init(false), cl::Hidden,
cl::desc("Enable Function Specialization pass"));
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")));
extern cl::opt<bool> EnableKnowledgeRetention;
} // namespace llvm
PassManagerBuilder::PassManagerBuilder() {
OptLevel = 2;
SizeLevel = 0;
LibraryInfo = nullptr;
Inliner = nullptr;
DisableUnrollLoops = false;
SLPVectorize = false;
LoopVectorize = true;
LoopsInterleaved = true;
RerollLoops = RunLoopRerolling;
NewGVN = RunNewGVN;
LicmMssaOptCap = SetLicmMssaOptCap;
LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap;
DisableGVNLoadPRE = false;
ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll;
VerifyInput = false;
VerifyOutput = false;
MergeFunctions = false;
PrepareForLTO = false;
EnablePGOInstrGen = false;
EnablePGOCSInstrGen = false;
EnablePGOCSInstrUse = false;
PGOInstrGen = "";
PGOInstrUse = "";
PGOSampleUse = "";
PrepareForThinLTO = EnablePrepareForThinLTO;
PerformThinLTO = EnablePerformThinLTO;
DivergentTarget = false;
CallGraphProfile = true;
}
PassManagerBuilder::~PassManagerBuilder() {
delete LibraryInfo;
delete Inliner;
}
/// Set of global extensions, automatically added as part of the standard set.
static ManagedStatic<
SmallVector<std::tuple<PassManagerBuilder::ExtensionPointTy,
PassManagerBuilder::ExtensionFn,
PassManagerBuilder::GlobalExtensionID>,
8>>
GlobalExtensions;
static PassManagerBuilder::GlobalExtensionID GlobalExtensionsCounter;
/// Check if GlobalExtensions is constructed and not empty.
/// Since GlobalExtensions is a managed static, calling 'empty()' will trigger
/// the construction of the object.
static bool GlobalExtensionsNotEmpty() {
return GlobalExtensions.isConstructed() && !GlobalExtensions->empty();
}
PassManagerBuilder::GlobalExtensionID
PassManagerBuilder::addGlobalExtension(PassManagerBuilder::ExtensionPointTy Ty,
PassManagerBuilder::ExtensionFn Fn) {
auto ExtensionID = GlobalExtensionsCounter++;
GlobalExtensions->push_back(std::make_tuple(Ty, std::move(Fn), ExtensionID));
return ExtensionID;
}
void PassManagerBuilder::removeGlobalExtension(
PassManagerBuilder::GlobalExtensionID ExtensionID) {
// RegisterStandardPasses may try to call this function after GlobalExtensions
// has already been destroyed; doing so should not generate an error.
if (!GlobalExtensions.isConstructed())
return;
auto GlobalExtension =
llvm::find_if(*GlobalExtensions, [ExtensionID](const auto &elem) {
return std::get<2>(elem) == ExtensionID;
});
assert(GlobalExtension != GlobalExtensions->end() &&
"The extension ID to be removed should always be valid.");
GlobalExtensions->erase(GlobalExtension);
}
void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
Extensions.push_back(std::make_pair(Ty, std::move(Fn)));
}
void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy,
legacy::PassManagerBase &PM) const {
if (GlobalExtensionsNotEmpty()) {
for (auto &Ext : *GlobalExtensions) {
if (std::get<0>(Ext) == ETy)
std::get<1>(Ext)(*this, PM);
}
}
for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
if (Extensions[i].first == ETy)
Extensions[i].second(*this, PM);
}
void PassManagerBuilder::addInitialAliasAnalysisPasses(
legacy::PassManagerBase &PM) const {
switch (UseCFLAA) {
case ::CFLAAType::Steensgaard:
PM.add(createCFLSteensAAWrapperPass());
break;
case ::CFLAAType::Andersen:
PM.add(createCFLAndersAAWrapperPass());
break;
case ::CFLAAType::Both:
PM.add(createCFLSteensAAWrapperPass());
PM.add(createCFLAndersAAWrapperPass());
break;
default:
break;
}
// Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
// BasicAliasAnalysis wins if they disagree. This is intended to help
// support "obvious" type-punning idioms.
PM.add(createTypeBasedAAWrapperPass());
PM.add(createScopedNoAliasAAWrapperPass());
}
void PassManagerBuilder::populateFunctionPassManager(
legacy::FunctionPassManager &FPM) {
addExtensionsToPM(EP_EarlyAsPossible, FPM);
// Add LibraryInfo if we have some.
if (LibraryInfo)
FPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));
// The backends do not handle matrix intrinsics currently.
// Make sure they are also lowered in O0.
// FIXME: A lightweight version of the pass should run in the backend
// pipeline on demand.
if (EnableMatrix && OptLevel == 0)
FPM.add(createLowerMatrixIntrinsicsMinimalPass());
if (OptLevel == 0) return;
addInitialAliasAnalysisPasses(FPM);
// Lower llvm.expect to metadata before attempting transforms.
// Compare/branch metadata may alter the behavior of passes like SimplifyCFG.
FPM.add(createLowerExpectIntrinsicPass());
FPM.add(createCFGSimplificationPass());
FPM.add(createSROAPass());
FPM.add(createEarlyCSEPass());
}
// Do PGO instrumentation generation or use pass as the option specified.
void PassManagerBuilder::addPGOInstrPasses(legacy::PassManagerBase &MPM,
bool IsCS = false) {
if (IsCS) {
if (!EnablePGOCSInstrGen && !EnablePGOCSInstrUse)
return;
} else if (!EnablePGOInstrGen && PGOInstrUse.empty() && PGOSampleUse.empty())
return;
// Perform the preinline and cleanup passes for O1 and above.
// We will not do this inline for context sensitive PGO (when IsCS is true).
if (OptLevel > 0 && !DisablePreInliner && PGOSampleUse.empty() && !IsCS) {
// Create preinline pass. We construct an InlineParams object and specify
// the threshold here to avoid the command line options of the regular
// inliner to influence pre-inlining. The only fields of InlineParams we
// care about are DefaultThreshold and HintThreshold.
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.
// Use PreInlineThreshold for both -Os and -Oz. Not running preinliner makes
// the instrumented binary unusably large. Even if PreInlineThreshold is not
// correct thresold for -Oz, it is better than not running preinliner.
IP.HintThreshold = SizeLevel > 0 ? PreInlineThreshold : 325;
MPM.add(createFunctionInliningPass(IP));
MPM.add(createSROAPass());
MPM.add(createEarlyCSEPass()); // Catch trivial redundancies
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
MPM.add(createInstructionCombiningPass()); // Combine silly seq's
addExtensionsToPM(EP_Peephole, MPM);
}
if ((EnablePGOInstrGen && !IsCS) || (EnablePGOCSInstrGen && IsCS)) {
MPM.add(createPGOInstrumentationGenLegacyPass(IsCS));
// Add the profile lowering pass.
InstrProfOptions Options;
if (!PGOInstrGen.empty())
Options.InstrProfileOutput = PGOInstrGen;
Options.DoCounterPromotion = true;
Options.UseBFIInPromotion = IsCS;
MPM.add(createLoopRotatePass());
MPM.add(createInstrProfilingLegacyPass(Options, IsCS));
}
if (!PGOInstrUse.empty())
MPM.add(createPGOInstrumentationUseLegacyPass(PGOInstrUse, IsCS));
// Indirect call promotion that promotes intra-module targets only.
// For ThinLTO this is done earlier due to interactions with globalopt
// for imported functions. We don't run this at -O0.
if (OptLevel > 0 && !IsCS)
MPM.add(
createPGOIndirectCallPromotionLegacyPass(false, !PGOSampleUse.empty()));
}
void PassManagerBuilder::addFunctionSimplificationPasses(
legacy::PassManagerBase &MPM) {
// Start of function pass.
// Break up aggregate allocas, using SSAUpdater.
assert(OptLevel >= 1 && "Calling function optimizer with no optimization level!");
MPM.add(createSROAPass());
MPM.add(createEarlyCSEPass(true /* Enable mem-ssa. */)); // Catch trivial redundancies
if (EnableKnowledgeRetention)
MPM.add(createAssumeSimplifyPass());
if (OptLevel > 1) {
if (EnableGVNHoist)
MPM.add(createGVNHoistPass());
if (EnableGVNSink) {
MPM.add(createGVNSinkPass());
MPM.add(createCFGSimplificationPass());
}
}
if (EnableConstraintElimination)
MPM.add(createConstraintEliminationPass());
if (OptLevel > 1) {
// Speculative execution if the target has divergent branches; otherwise nop.
MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
MPM.add(createJumpThreadingPass()); // Thread jumps.
MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
}
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
// Combine silly seq's
if (OptLevel > 2)
MPM.add(createAggressiveInstCombinerPass());
MPM.add(createInstructionCombiningPass());
if (SizeLevel == 0 && !DisableLibCallsShrinkWrap)
MPM.add(createLibCallsShrinkWrapPass());
addExtensionsToPM(EP_Peephole, MPM);
// Optimize memory intrinsic calls based on the profiled size information.
if (SizeLevel == 0)
MPM.add(createPGOMemOPSizeOptLegacyPass());
// TODO: Investigate the cost/benefit of tail call elimination on debugging.
if (OptLevel > 1)
MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
MPM.add(createReassociatePass()); // Reassociate expressions
// Begin the loop pass pipeline.
if (EnableSimpleLoopUnswitch) {
// The simple loop unswitch pass relies on separate cleanup passes. Schedule
// them first so when we re-process a loop they run before other loop
// passes.
MPM.add(createLoopInstSimplifyPass());
MPM.add(createLoopSimplifyCFGPass());
}
// Try to remove as much code from the loop header as possible,
// to reduce amount of IR that will have to be duplicated.
// TODO: Investigate promotion cap for O1.
MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
// Rotate Loop - disable header duplication at -Oz
MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1, PrepareForLTO));
// TODO: Investigate promotion cap for O1.
MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
if (EnableSimpleLoopUnswitch)
MPM.add(createSimpleLoopUnswitchLegacyPass());
else
MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3, DivergentTarget));
// FIXME: We break the loop pass pipeline here in order to do full
// simplifycfg. Eventually loop-simplifycfg should be enhanced to replace the
// need for this.
MPM.add(createCFGSimplificationPass());
MPM.add(createInstructionCombiningPass());
// We resume loop passes creating a second loop pipeline here.
if (EnableLoopFlatten) {
MPM.add(createLoopFlattenPass()); // Flatten loops
MPM.add(createLoopSimplifyCFGPass());
}
MPM.add(createLoopIdiomPass()); // Recognize idioms like memset.
MPM.add(createIndVarSimplifyPass()); // Canonicalize indvars
addExtensionsToPM(EP_LateLoopOptimizations, MPM);
MPM.add(createLoopDeletionPass()); // Delete dead loops
if (EnableLoopInterchange)
MPM.add(createLoopInterchangePass()); // Interchange loops
// Unroll small loops and perform peeling.
MPM.add(createSimpleLoopUnrollPass(OptLevel, DisableUnrollLoops,
ForgetAllSCEVInLoopUnroll));
addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
// This ends the loop pass pipelines.
// Break up allocas that may now be splittable after loop unrolling.
MPM.add(createSROAPass());
if (OptLevel > 1) {
MPM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds
MPM.add(NewGVN ? createNewGVNPass()
: createGVNPass(DisableGVNLoadPRE)); // Remove redundancies
}
MPM.add(createSCCPPass()); // Constant prop with SCCP
if (EnableConstraintElimination)
MPM.add(createConstraintEliminationPass());
// 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).
MPM.add(createBitTrackingDCEPass()); // Delete dead bit computations
// Run instcombine after redundancy elimination to exploit opportunities
// opened up by them.
MPM.add(createInstructionCombiningPass());
addExtensionsToPM(EP_Peephole, MPM);
if (OptLevel > 1) {
if (EnableDFAJumpThreading && SizeLevel == 0)
MPM.add(createDFAJumpThreadingPass());
MPM.add(createJumpThreadingPass()); // Thread jumps
MPM.add(createCorrelatedValuePropagationPass());
}
MPM.add(createAggressiveDCEPass()); // Delete dead instructions
MPM.add(createMemCpyOptPass()); // Remove memcpy / form memset
// TODO: Investigate if this is too expensive at O1.
if (OptLevel > 1) {
MPM.add(createDeadStoreEliminationPass()); // Delete dead stores
MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
}
addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
if (RerollLoops)
MPM.add(createLoopRerollPass());
// Merge & remove BBs and sink & hoist common instructions.
MPM.add(createCFGSimplificationPass(
SimplifyCFGOptions().hoistCommonInsts(true).sinkCommonInsts(true)));
// Clean up after everything.
MPM.add(createInstructionCombiningPass());
addExtensionsToPM(EP_Peephole, MPM);
if (EnableCHR && OptLevel >= 3 &&
(!PGOInstrUse.empty() || !PGOSampleUse.empty() || EnablePGOCSInstrGen))
MPM.add(createControlHeightReductionLegacyPass());
}
/// FIXME: Should LTO cause any differences to this set of passes?
void PassManagerBuilder::addVectorPasses(legacy::PassManagerBase &PM,
bool IsFullLTO) {
PM.add(createLoopVectorizePass(!LoopsInterleaved, !LoopVectorize));
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 && !DisableUnrollLoops)
PM.add(createLoopUnrollAndJamPass(OptLevel));
PM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops,
ForgetAllSCEVInLoopUnroll));
PM.add(createWarnMissedTransformationsPass());
}
if (!IsFullLTO) {
// Eliminate loads by forwarding stores from the previous iteration to loads
// of the current iteration.
PM.add(createLoopLoadEliminationPass());
}
// Cleanup after the loop optimization passes.
PM.add(createInstructionCombiningPass());
if (OptLevel > 1 && ExtraVectorizerPasses) {
// 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.
PM.add(createEarlyCSEPass());
PM.add(createCorrelatedValuePropagationPass());
PM.add(createInstructionCombiningPass());
PM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
PM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3, DivergentTarget));
PM.add(createCFGSimplificationPass());
PM.add(createInstructionCombiningPass());
}
// 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.
PM.add(createCFGSimplificationPass(SimplifyCFGOptions()
.forwardSwitchCondToPhi(true)
.convertSwitchToLookupTable(true)
.needCanonicalLoops(false)
.hoistCommonInsts(true)
.sinkCommonInsts(true)));
if (IsFullLTO) {
PM.add(createSCCPPass()); // Propagate exposed constants
PM.add(createInstructionCombiningPass()); // Clean up again
PM.add(createBitTrackingDCEPass());
}
// Optimize parallel scalar instruction chains into SIMD instructions.
if (SLPVectorize) {
PM.add(createSLPVectorizerPass());
if (OptLevel > 1 && ExtraVectorizerPasses)
PM.add(createEarlyCSEPass());
}
// Enhance/cleanup vector code.
PM.add(createVectorCombinePass());
if (!IsFullLTO) {
addExtensionsToPM(EP_Peephole, PM);
PM.add(createInstructionCombiningPass());
if (EnableUnrollAndJam && !DisableUnrollLoops) {
// Unroll and Jam. We do this before unroll but need to be in a separate
// loop pass manager in order for the outer loop to be processed by
// unroll and jam before the inner loop is unrolled.
PM.add(createLoopUnrollAndJamPass(OptLevel));
}
// Unroll small loops
PM.add(createLoopUnrollPass(OptLevel, DisableUnrollLoops,
ForgetAllSCEVInLoopUnroll));
if (!DisableUnrollLoops) {
// LoopUnroll may generate some redundency to cleanup.
PM.add(createInstructionCombiningPass());
// Runtime unrolling will introduce runtime check in loop prologue. If the
// unrolled loop is a inner loop, then the prologue will be inside the
// outer loop. LICM pass can help to promote the runtime check out if the
// checked value is loop invariant.
PM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
}
PM.add(createWarnMissedTransformationsPass());
}
// After vectorization and unrolling, assume intrinsics may tell us more
// about pointer alignments.
PM.add(createAlignmentFromAssumptionsPass());
if (IsFullLTO)
PM.add(createInstructionCombiningPass());
}
void PassManagerBuilder::populateModulePassManager(
legacy::PassManagerBase &MPM) {
// Whether this is a default or *LTO pre-link pipeline. The FullLTO post-link
// is handled separately, so just check this is not the ThinLTO post-link.
bool DefaultOrPreLinkPipeline = !PerformThinLTO;
MPM.add(createAnnotation2MetadataLegacyPass());
if (!PGOSampleUse.empty()) {
MPM.add(createPruneEHPass());
// 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.
if (!(FlattenedProfileUsed && PerformThinLTO))
MPM.add(createSampleProfileLoaderPass(PGOSampleUse));
}
// Allow forcing function attributes as a debugging and tuning aid.
MPM.add(createForceFunctionAttrsLegacyPass());
// If all optimizations are disabled, just run the always-inline pass and,
// if enabled, the function merging pass.
if (OptLevel == 0) {
addPGOInstrPasses(MPM);
if (Inliner) {
MPM.add(Inliner);
Inliner = nullptr;
}
// FIXME: The BarrierNoopPass is a HACK! The inliner pass above implicitly
// creates a CGSCC pass manager, but we don't want to add extensions into
// that pass manager. To prevent this we insert a no-op module pass to reset
// the pass manager to get the same behavior as EP_OptimizerLast in non-O0
// builds. The function merging pass is
if (MergeFunctions)
MPM.add(createMergeFunctionsPass());
else if (GlobalExtensionsNotEmpty() || !Extensions.empty())
MPM.add(createBarrierNoopPass());
if (PerformThinLTO) {
MPM.add(createLowerTypeTestsPass(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.add(createEliminateAvailableExternallyPass());
MPM.add(createGlobalDCEPass());
}
addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
if (PrepareForLTO || PrepareForThinLTO) {
MPM.add(createCanonicalizeAliasesPass());
// Rename anon globals to be able to export them in the summary.
// This has to be done after we add the extensions to the pass manager
// as there could be passes (e.g. Adddress sanitizer) which introduce
// new unnamed globals.
MPM.add(createNameAnonGlobalPass());
}
MPM.add(createAnnotationRemarksLegacyPass());
return;
}
// Add LibraryInfo if we have some.
if (LibraryInfo)
MPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));
addInitialAliasAnalysisPasses(MPM);
// For ThinLTO there are two passes of indirect call promotion. The
// first is during the compile phase when PerformThinLTO=false and
// intra-module indirect call targets are promoted. The second is during
// the ThinLTO backend when PerformThinLTO=true, when we promote imported
// inter-module indirect calls. For that we perform indirect call promotion
// earlier in the pass pipeline, here before globalopt. Otherwise imported
// available_externally functions look unreferenced and are removed.
if (PerformThinLTO) {
MPM.add(createPGOIndirectCallPromotionLegacyPass(/*InLTO = */ true,
!PGOSampleUse.empty()));
MPM.add(createLowerTypeTestsPass(nullptr, nullptr, true));
}
// For SamplePGO in ThinLTO compile phase, we do not want to unroll loops
// as it will change the CFG too much to make the 2nd profile annotation
// in backend more difficult.
bool PrepareForThinLTOUsingPGOSampleProfile =
PrepareForThinLTO && !PGOSampleUse.empty();
if (PrepareForThinLTOUsingPGOSampleProfile)
DisableUnrollLoops = true;
// Infer attributes about declarations if possible.
MPM.add(createInferFunctionAttrsLegacyPass());
// Infer attributes on declarations, call sites, arguments, etc.
if (AttributorRun & AttributorRunOption::MODULE)
MPM.add(createAttributorLegacyPass());
addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
if (OptLevel > 2)
MPM.add(createCallSiteSplittingPass());
// Propage constant function arguments by specializing the functions.
if (OptLevel > 2 && EnableFunctionSpecialization)
MPM.add(createFunctionSpecializationPass());
MPM.add(createIPSCCPPass()); // IP SCCP
MPM.add(createCalledValuePropagationPass());
MPM.add(createGlobalOptimizerPass()); // Optimize out global vars
// Promote any localized global vars.
MPM.add(createPromoteMemoryToRegisterPass());
MPM.add(createDeadArgEliminationPass()); // Dead argument elimination
MPM.add(createInstructionCombiningPass()); // Clean up after IPCP & DAE
addExtensionsToPM(EP_Peephole, MPM);
MPM.add(createCFGSimplificationPass()); // Clean up after IPCP & DAE
// For SamplePGO in ThinLTO compile phase, we do not want to do indirect
// call promotion as it will change the CFG too much to make the 2nd
// profile annotation in backend more difficult.
// PGO instrumentation is added during the compile phase for ThinLTO, do
// not run it a second time
if (DefaultOrPreLinkPipeline && !PrepareForThinLTOUsingPGOSampleProfile)
addPGOInstrPasses(MPM);
// Create profile COMDAT variables. Lld linker wants to see all variables
// before the LTO/ThinLTO link since it needs to resolve symbols/comdats.
if (!PerformThinLTO && EnablePGOCSInstrGen)
MPM.add(createPGOInstrumentationGenCreateVarLegacyPass(PGOInstrGen));
// We add a module alias analysis pass here. In part due to bugs in the
// analysis infrastructure this "works" in that the analysis stays alive
// for the entire SCC pass run below.
MPM.add(createGlobalsAAWrapperPass());
// Start of CallGraph SCC passes.
MPM.add(createPruneEHPass()); // Remove dead EH info
bool RunInliner = false;
if (Inliner) {
MPM.add(Inliner);
Inliner = nullptr;
RunInliner = true;
}
// Infer attributes on declarations, call sites, arguments, etc. for an SCC.
if (AttributorRun & AttributorRunOption::CGSCC)
MPM.add(createAttributorCGSCCLegacyPass());
// Try to perform OpenMP specific optimizations. This is a (quick!) no-op if
// there are no OpenMP runtime calls present in the module.
if (OptLevel > 1)
MPM.add(createOpenMPOptCGSCCLegacyPass());
MPM.add(createPostOrderFunctionAttrsLegacyPass());
if (OptLevel > 2)
MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args
addExtensionsToPM(EP_CGSCCOptimizerLate, MPM);
addFunctionSimplificationPasses(MPM);
// FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
// pass manager that we are specifically trying to avoid. To prevent this
// we must insert a no-op module pass to reset the pass manager.
MPM.add(createBarrierNoopPass());
if (RunPartialInlining)
MPM.add(createPartialInliningPass());
if (OptLevel > 1 && !PrepareForLTO && !PrepareForThinLTO)
// Remove avail extern fns and globals definitions if 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.
MPM.add(createEliminateAvailableExternallyPass());
// CSFDO instrumentation and use pass. Don't invoke this for Prepare pass
// for LTO and ThinLTO -- The actual pass will be called after all inlines
// are performed.
// Need to do this after COMDAT variables have been eliminated,
// (i.e. after EliminateAvailableExternallyPass).
if (!(PrepareForLTO || PrepareForThinLTO))
addPGOInstrPasses(MPM, /* IsCS */ true);
if (EnableOrderFileInstrumentation)
MPM.add(createInstrOrderFilePass());
MPM.add(createReversePostOrderFunctionAttrsPass());
// The inliner performs some kind of dead code elimination as it goes,
// but there are cases that are not really caught by it. We might
// at some point consider teaching the inliner about them, but it
// is OK for now to run GlobalOpt + GlobalDCE in tandem as their
// benefits generally outweight the cost, making the whole pipeline
// faster.
if (RunInliner) {
MPM.add(createGlobalOptimizerPass());
MPM.add(createGlobalDCEPass());
}
// If we are planning to perform ThinLTO later, let's not bloat the code with
// unrolling/vectorization/... now. We'll first run the inliner + CGSCC passes
// during ThinLTO and perform the rest of the optimizations afterward.
if (PrepareForThinLTO) {
// Ensure we perform any last passes, but do so before renaming anonymous
// globals in case the passes add any.
addExtensionsToPM(EP_OptimizerLast, MPM);
MPM.add(createCanonicalizeAliasesPass());
// Rename anon globals to be able to export them in the summary.
MPM.add(createNameAnonGlobalPass());
return;
}
if (PerformThinLTO)
// Optimize globals now when performing ThinLTO, this enables more
// optimizations later.
MPM.add(createGlobalOptimizerPass());
// 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. By placing it just after inlining other optimizations which runs
// later might get benefit of no-alias assumption in clone loop.
if (UseLoopVersioningLICM) {
MPM.add(createLoopVersioningLICMPass()); // Do LoopVersioningLICM
MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
}
// We add a fresh GlobalsModRef run at this point. 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.
//
// Note that this relies on a bug in the pass manager which preserves
// a module analysis into a function pass pipeline (and throughout it) so
// long as the first function pass doesn't invalidate the module analysis.
// Thus both Float2Int and LoopRotate have to preserve AliasAnalysis for
// this to work. Fortunately, it is trivial to preserve AliasAnalysis
// (doing nothing preserves it as it is required to be conservatively
// correct in the face of IR changes).
MPM.add(createGlobalsAAWrapperPass());
MPM.add(createFloat2IntPass());
MPM.add(createLowerConstantIntrinsicsPass());
if (EnableMatrix) {
MPM.add(createLowerMatrixIntrinsicsPass());
// CSE the pointer arithmetic of the column vectors. This allows alias
// analysis to establish no-aliasing between loads and stores of different
// columns of the same matrix.
MPM.add(createEarlyCSEPass(false));
}
addExtensionsToPM(EP_VectorizerStart, MPM);
// Re-rotate loops in all our loop nests. These may have fallout out of
// rotated form due to GVN or other transformations, and the vectorizer relies
// on the rotated form. Disable header duplication at -Oz.
MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1, PrepareForLTO));
// 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.
MPM.add(createLoopDistributePass());
addVectorPasses(MPM, /* IsFullLTO */ false);
// FIXME: We shouldn't bother with this anymore.
MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
// GlobalOpt already deletes dead functions and globals, at -O2 try a
// late pass of GlobalDCE. It is capable of deleting dead cycles.
if (OptLevel > 1) {
MPM.add(createGlobalDCEPass()); // Remove dead fns and globals.
MPM.add(createConstantMergePass()); // Merge dup global constants
}
// See comment in the new PM for justification of scheduling splitting at
// this stage (\ref buildModuleSimplificationPipeline).
if (EnableHotColdSplit && !(PrepareForLTO || PrepareForThinLTO))
MPM.add(createHotColdSplittingPass());
if (EnableIROutliner)
MPM.add(createIROutlinerPass());
if (MergeFunctions)
MPM.add(createMergeFunctionsPass());
// Add Module flag "CG Profile" based on Branch Frequency Information.
if (CallGraphProfile)
MPM.add(createCGProfileLegacyPass());
// 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.
MPM.add(createLoopSinkPass());
// Get rid of LCSSA nodes.
MPM.add(createInstSimplifyLegacyPass());
// 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.
MPM.add(createDivRemPairsPass());
// LoopSink (and other loop passes since the last simplifyCFG) might have
// resulted in single-entry-single-exit or empty blocks. Clean up the CFG.
MPM.add(createCFGSimplificationPass());
addExtensionsToPM(EP_OptimizerLast, MPM);
if (PrepareForLTO) {
MPM.add(createCanonicalizeAliasesPass());
// Rename anon globals to be able to handle them in the summary
MPM.add(createNameAnonGlobalPass());
}
MPM.add(createAnnotationRemarksLegacyPass());
}
void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
// Load sample profile before running the LTO optimization pipeline.
if (!PGOSampleUse.empty()) {
PM.add(createPruneEHPass());
PM.add(createSampleProfileLoaderPass(PGOSampleUse));
}
// Remove unused virtual tables to improve the quality of code generated by
// whole-program devirtualization and bitset lowering.
PM.add(createGlobalDCEPass());
// Provide AliasAnalysis services for optimizations.
addInitialAliasAnalysisPasses(PM);
// Allow forcing function attributes as a debugging and tuning aid.
PM.add(createForceFunctionAttrsLegacyPass());
// Infer attributes about declarations if possible.