1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-20 19:42:54 +02:00
llvm-mirror/include/llvm/InitializePasses.h
Adam Nemet 933537bc6b LLE 6/6: Add LoopLoadElimination pass
Summary:
The goal of this pass is to perform store-to-load forwarding across the
backedge of a loop.  E.g.:

  for (i)
     A[i + 1] = A[i] + B[i]

  =>

  T = A[0]
  for (i)
     T = T + B[i]
     A[i + 1] = T

The pass relies on loop dependence analysis via LoopAccessAnalisys to
find opportunities of loop-carried dependences with a distance of one
between a store and a load.  Since it's using LoopAccessAnalysis, it was
easy to also add support for versioning away may-aliasing intervening
stores that would otherwise prevent this transformation.

This optimization is also performed by Load-PRE in GVN without the
option of multi-versioning.  As was discussed with Daniel Berlin in
http://reviews.llvm.org/D9548, this is inferior to a more loop-aware
solution applied here.  Hopefully, we will be able to remove some
complexity from GVN/MemorySSA as a consequence.

In the long run, we may want to extend this pass (or create a new one if
there is little overlap) to also eliminate loop-indepedent redundant
loads and store that *require* versioning due to may-aliasing
intervening stores/loads.  I have some motivating cases for store
elimination. My plan right now is to wait for MemorySSA to come online
first rather than using memdep for this.

The main motiviation for this pass is the 456.hmmer loop in SPECint2006
where after distributing the original loop and vectorizing the top part,
we are left with the critical path exposed in the bottom loop.  Being
able to promote the memory dependence into a register depedence (even
though the HW does perform store-to-load fowarding as well) results in a
major gain (~20%).  This gain also transfers over to x86: it's
around 8-10%.

Right now the pass is off by default and can be enabled
with -enable-loop-load-elim.  On the LNT testsuite, there are two
performance changes (negative number -> improvement):

  1. -28% in Polybench/linear-algebra/solvers/dynprog: the length of the
     critical paths is reduced
  2. +2% in Polybench/stencils/adi: Unfortunately, I couldn't reproduce this
     outside of LNT

The pass is scheduled after the loop vectorizer (which is after loop
distribution).  The rational is to try to reuse LAA state, rather than
recomputing it.  The order between LV and LLE is not critical because
normally LV does not touch scalar st->ld forwarding cases where
vectorizing would inhibit the CPU's st->ld forwarding to kick in.

LoopLoadElimination requires LAA to provide the full set of dependences
(including forward dependences).  LAA is known to omit loop-independent
dependences in certain situations.  The big comment before
removeDependencesFromMultipleStores explains why this should not occur
for the cases that we're interested in.

Reviewers: dberlin, hfinkel

Subscribers: junbuml, dberlin, mssimpso, rengolin, sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D13259

llvm-svn: 252017
2015-11-03 23:50:08 +00:00

308 lines
14 KiB
C++

//===- llvm/InitializePasses.h -------- Initialize All Passes ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declarations for the pass initialization routines
// for the entire LLVM project.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_INITIALIZEPASSES_H
#define LLVM_INITIALIZEPASSES_H
namespace llvm {
class PassRegistry;
/// initializeCore - Initialize all passes linked into the
/// TransformUtils library.
void initializeCore(PassRegistry&);
/// initializeTransformUtils - Initialize all passes linked into the
/// TransformUtils library.
void initializeTransformUtils(PassRegistry&);
/// initializeScalarOpts - Initialize all passes linked into the
/// ScalarOpts library.
void initializeScalarOpts(PassRegistry&);
/// initializeObjCARCOpts - Initialize all passes linked into the ObjCARCOpts
/// library.
void initializeObjCARCOpts(PassRegistry&);
/// initializeVectorization - Initialize all passes linked into the
/// Vectorize library.
void initializeVectorization(PassRegistry&);
/// initializeInstCombine - Initialize all passes linked into the
/// InstCombine library.
void initializeInstCombine(PassRegistry&);
/// initializeIPO - Initialize all passes linked into the IPO library.
void initializeIPO(PassRegistry&);
/// initializeInstrumentation - Initialize all passes linked into the
/// Instrumentation library.
void initializeInstrumentation(PassRegistry&);
/// initializeAnalysis - Initialize all passes linked into the Analysis library.
void initializeAnalysis(PassRegistry&);
/// initializeCodeGen - Initialize all passes linked into the CodeGen library.
void initializeCodeGen(PassRegistry&);
/// initializeCodeGen - Initialize all passes linked into the CodeGen library.
void initializeTarget(PassRegistry&);
void initializeAAEvalPass(PassRegistry&);
void initializeAddDiscriminatorsPass(PassRegistry&);
void initializeADCELegacyPassPass(PassRegistry&);
void initializeBDCEPass(PassRegistry&);
void initializeAliasSetPrinterPass(PassRegistry&);
void initializeAlwaysInlinerPass(PassRegistry&);
void initializeArgPromotionPass(PassRegistry&);
void initializeAtomicExpandPass(PassRegistry&);
void initializeSampleProfileLoaderPass(PassRegistry&);
void initializeAlignmentFromAssumptionsPass(PassRegistry&);
void initializeBarrierNoopPass(PassRegistry&);
void initializeBasicAAWrapperPassPass(PassRegistry&);
void initializeCallGraphWrapperPassPass(PassRegistry &);
void initializeBlockExtractorPassPass(PassRegistry&);
void initializeBlockFrequencyInfoWrapperPassPass(PassRegistry&);
void initializeBoundsCheckingPass(PassRegistry&);
void initializeBranchFolderPassPass(PassRegistry&);
void initializeBranchProbabilityInfoWrapperPassPass(PassRegistry&);
void initializeBreakCriticalEdgesPass(PassRegistry&);
void initializeCallGraphPrinterPass(PassRegistry&);
void initializeCallGraphViewerPass(PassRegistry&);
void initializeCFGOnlyPrinterPass(PassRegistry&);
void initializeCFGOnlyViewerPass(PassRegistry&);
void initializeCFGPrinterPass(PassRegistry&);
void initializeCFGSimplifyPassPass(PassRegistry&);
void initializeCFLAAWrapperPassPass(PassRegistry&);
void initializeExternalAAWrapperPassPass(PassRegistry&);
void initializeForwardControlFlowIntegrityPass(PassRegistry&);
void initializeFlattenCFGPassPass(PassRegistry&);
void initializeStructurizeCFGPass(PassRegistry&);
void initializeCFGViewerPass(PassRegistry&);
void initializeConstantHoistingPass(PassRegistry&);
void initializeCodeGenPreparePass(PassRegistry&);
void initializeConstantMergePass(PassRegistry&);
void initializeConstantPropagationPass(PassRegistry&);
void initializeMachineCopyPropagationPass(PassRegistry&);
void initializeCostModelAnalysisPass(PassRegistry&);
void initializeCorrelatedValuePropagationPass(PassRegistry&);
void initializeDAEPass(PassRegistry&);
void initializeDAHPass(PassRegistry&);
void initializeDCEPass(PassRegistry&);
void initializeDSEPass(PassRegistry&);
void initializeDeadInstEliminationPass(PassRegistry&);
void initializeDeadMachineInstructionElimPass(PassRegistry&);
void initializeDelinearizationPass(PassRegistry &);
void initializeDependenceAnalysisPass(PassRegistry&);
void initializeDivergenceAnalysisPass(PassRegistry&);
void initializeDomOnlyPrinterPass(PassRegistry&);
void initializeDomOnlyViewerPass(PassRegistry&);
void initializeDomPrinterPass(PassRegistry&);
void initializeDomViewerPass(PassRegistry&);
void initializeDominanceFrontierPass(PassRegistry&);
void initializeDominatorTreeWrapperPassPass(PassRegistry&);
void initializeEarlyIfConverterPass(PassRegistry&);
void initializeEdgeBundlesPass(PassRegistry&);
void initializeExpandPostRAPass(PassRegistry&);
void initializeAAResultsWrapperPassPass(PassRegistry &);
void initializeGCOVProfilerPass(PassRegistry&);
void initializeInstrProfilingPass(PassRegistry&);
void initializeAddressSanitizerPass(PassRegistry&);
void initializeAddressSanitizerModulePass(PassRegistry&);
void initializeMemorySanitizerPass(PassRegistry&);
void initializeThreadSanitizerPass(PassRegistry&);
void initializeSanitizerCoverageModulePass(PassRegistry&);
void initializeDataFlowSanitizerPass(PassRegistry&);
void initializeScalarizerPass(PassRegistry&);
void initializeEarlyCSELegacyPassPass(PassRegistry &);
void initializeEliminateAvailableExternallyPass(PassRegistry&);
void initializeExpandISelPseudosPass(PassRegistry&);
void initializeFunctionAttrsPass(PassRegistry&);
void initializeGCMachineCodeAnalysisPass(PassRegistry&);
void initializeGCModuleInfoPass(PassRegistry&);
void initializeGVNPass(PassRegistry&);
void initializeGlobalDCEPass(PassRegistry&);
void initializeGlobalOptPass(PassRegistry&);
void initializeGlobalsAAWrapperPassPass(PassRegistry&);
void initializeIPCPPass(PassRegistry&);
void initializeIPSCCPPass(PassRegistry&);
void initializeIVUsersPass(PassRegistry&);
void initializeIfConverterPass(PassRegistry&);
void initializeInductiveRangeCheckEliminationPass(PassRegistry&);
void initializeIndVarSimplifyPass(PassRegistry&);
void initializeInlineCostAnalysisPass(PassRegistry&);
void initializeInstructionCombiningPassPass(PassRegistry&);
void initializeInstCountPass(PassRegistry&);
void initializeInstNamerPass(PassRegistry&);
void initializeInternalizePassPass(PassRegistry&);
void initializeIntervalPartitionPass(PassRegistry&);
void initializeJumpThreadingPass(PassRegistry&);
void initializeLCSSAPass(PassRegistry&);
void initializeLICMPass(PassRegistry&);
void initializeLazyValueInfoPass(PassRegistry&);
void initializeLintPass(PassRegistry&);
void initializeLiveDebugVariablesPass(PassRegistry&);
void initializeLiveIntervalsPass(PassRegistry&);
void initializeLiveRegMatrixPass(PassRegistry&);
void initializeLiveStacksPass(PassRegistry&);
void initializeLiveVariablesPass(PassRegistry&);
void initializeLoaderPassPass(PassRegistry&);
void initializeLocalStackSlotPassPass(PassRegistry&);
void initializeLoopDeletionPass(PassRegistry&);
void initializeLoopExtractorPass(PassRegistry&);
void initializeLoopInfoWrapperPassPass(PassRegistry&);
void initializeLoopInterchangePass(PassRegistry &);
void initializeLoopInstSimplifyPass(PassRegistry&);
void initializeLoopRotatePass(PassRegistry&);
void initializeLoopSimplifyPass(PassRegistry&);
void initializeLoopStrengthReducePass(PassRegistry&);
void initializeGlobalMergePass(PassRegistry&);
void initializeLoopRerollPass(PassRegistry&);
void initializeLoopUnrollPass(PassRegistry&);
void initializeLoopUnswitchPass(PassRegistry&);
void initializeLoopIdiomRecognizePass(PassRegistry&);
void initializeLowerAtomicPass(PassRegistry&);
void initializeLowerBitSetsPass(PassRegistry&);
void initializeLowerExpectIntrinsicPass(PassRegistry&);
void initializeLowerIntrinsicsPass(PassRegistry&);
void initializeLowerInvokePass(PassRegistry&);
void initializeLowerSwitchPass(PassRegistry&);
void initializeMachineBlockFrequencyInfoPass(PassRegistry&);
void initializeMachineBlockPlacementPass(PassRegistry&);
void initializeMachineBlockPlacementStatsPass(PassRegistry&);
void initializeMachineBranchProbabilityInfoPass(PassRegistry&);
void initializeMachineCSEPass(PassRegistry&);
void initializeImplicitNullChecksPass(PassRegistry&);
void initializeMachineDominatorTreePass(PassRegistry&);
void initializeMachineDominanceFrontierPass(PassRegistry&);
void initializeMachinePostDominatorTreePass(PassRegistry&);
void initializeMachineLICMPass(PassRegistry&);
void initializeMachineLoopInfoPass(PassRegistry&);
void initializeMachineModuleInfoPass(PassRegistry&);
void initializeMachineRegionInfoPassPass(PassRegistry&);
void initializeMachineSchedulerPass(PassRegistry&);
void initializeMachineSinkingPass(PassRegistry&);
void initializeMachineTraceMetricsPass(PassRegistry&);
void initializeMachineVerifierPassPass(PassRegistry&);
void initializeMemCpyOptPass(PassRegistry&);
void initializeMemDepPrinterPass(PassRegistry&);
void initializeMemDerefPrinterPass(PassRegistry&);
void initializeMemoryDependenceAnalysisPass(PassRegistry&);
void initializeMergedLoadStoreMotionPass(PassRegistry &);
void initializeMetaRenamerPass(PassRegistry&);
void initializeMergeFunctionsPass(PassRegistry&);
void initializeModuleDebugInfoPrinterPass(PassRegistry&);
void initializeNaryReassociatePass(PassRegistry&);
void initializeNoAAPass(PassRegistry&);
void initializeObjCARCAAWrapperPassPass(PassRegistry&);
void initializeObjCARCAPElimPass(PassRegistry&);
void initializeObjCARCExpandPass(PassRegistry&);
void initializeObjCARCContractPass(PassRegistry&);
void initializeObjCARCOptPass(PassRegistry&);
void initializePAEvalPass(PassRegistry &);
void initializeOptimizePHIsPass(PassRegistry&);
void initializePartiallyInlineLibCallsPass(PassRegistry&);
void initializePEIPass(PassRegistry&);
void initializePHIEliminationPass(PassRegistry&);
void initializePartialInlinerPass(PassRegistry&);
void initializePeepholeOptimizerPass(PassRegistry&);
void initializePostDomOnlyPrinterPass(PassRegistry&);
void initializePostDomOnlyViewerPass(PassRegistry&);
void initializePostDomPrinterPass(PassRegistry&);
void initializePostDomViewerPass(PassRegistry&);
void initializePostDominatorTreePass(PassRegistry&);
void initializePostRASchedulerPass(PassRegistry&);
void initializePostMachineSchedulerPass(PassRegistry&);
void initializePrintFunctionPassWrapperPass(PassRegistry&);
void initializePrintModulePassWrapperPass(PassRegistry&);
void initializePrintBasicBlockPassPass(PassRegistry&);
void initializeProcessImplicitDefsPass(PassRegistry&);
void initializePromotePassPass(PassRegistry&);
void initializePruneEHPass(PassRegistry&);
void initializeReassociatePass(PassRegistry&);
void initializeRegToMemPass(PassRegistry&);
void initializeRegionInfoPassPass(PassRegistry&);
void initializeRegionOnlyPrinterPass(PassRegistry&);
void initializeRegionOnlyViewerPass(PassRegistry&);
void initializeRegionPrinterPass(PassRegistry&);
void initializeRegionViewerPass(PassRegistry&);
void initializeRewriteStatepointsForGCPass(PassRegistry&);
void initializeSafeStackPass(PassRegistry&);
void initializeSCCPPass(PassRegistry&);
void initializeSROALegacyPassPass(PassRegistry&);
void initializeSROA_DTPass(PassRegistry&);
void initializeSROA_SSAUpPass(PassRegistry&);
void initializeSCEVAAWrapperPassPass(PassRegistry&);
void initializeScalarEvolutionWrapperPassPass(PassRegistry&);
void initializeShrinkWrapPass(PassRegistry &);
void initializeSimpleInlinerPass(PassRegistry&);
void initializeShadowStackGCLoweringPass(PassRegistry&);
void initializeRegisterCoalescerPass(PassRegistry&);
void initializeSingleLoopExtractorPass(PassRegistry&);
void initializeSinkingPass(PassRegistry&);
void initializeSeparateConstOffsetFromGEPPass(PassRegistry &);
void initializeSlotIndexesPass(PassRegistry&);
void initializeSpillPlacementPass(PassRegistry&);
void initializeSpeculativeExecutionPass(PassRegistry&);
void initializeStackProtectorPass(PassRegistry&);
void initializeStackColoringPass(PassRegistry&);
void initializeStackSlotColoringPass(PassRegistry&);
void initializeStraightLineStrengthReducePass(PassRegistry &);
void initializeStripDeadDebugInfoPass(PassRegistry&);
void initializeStripDeadPrototypesLegacyPassPass(PassRegistry&);
void initializeStripDebugDeclarePass(PassRegistry&);
void initializeStripNonDebugSymbolsPass(PassRegistry&);
void initializeStripSymbolsPass(PassRegistry&);
void initializeTailCallElimPass(PassRegistry&);
void initializeTailDuplicatePassPass(PassRegistry&);
void initializeTargetPassConfigPass(PassRegistry&);
void initializeTargetTransformInfoWrapperPassPass(PassRegistry &);
void initializeTargetLibraryInfoWrapperPassPass(PassRegistry &);
void initializeAssumptionCacheTrackerPass(PassRegistry &);
void initializeTwoAddressInstructionPassPass(PassRegistry&);
void initializeTypeBasedAAWrapperPassPass(PassRegistry&);
void initializeScopedNoAliasAAWrapperPassPass(PassRegistry&);
void initializeUnifyFunctionExitNodesPass(PassRegistry&);
void initializeUnreachableBlockElimPass(PassRegistry&);
void initializeUnreachableMachineBlockElimPass(PassRegistry&);
void initializeVerifierLegacyPassPass(PassRegistry&);
void initializeVirtRegMapPass(PassRegistry&);
void initializeVirtRegRewriterPass(PassRegistry&);
void initializeInstSimplifierPass(PassRegistry&);
void initializeUnpackMachineBundlesPass(PassRegistry&);
void initializeFinalizeMachineBundlesPass(PassRegistry&);
void initializeLoopAccessAnalysisPass(PassRegistry&);
void initializeLoopVectorizePass(PassRegistry&);
void initializeSLPVectorizerPass(PassRegistry&);
void initializeBBVectorizePass(PassRegistry&);
void initializeMachineFunctionPrinterPassPass(PassRegistry&);
void initializeMIRPrintingPassPass(PassRegistry&);
void initializeStackMapLivenessPass(PassRegistry&);
void initializeMachineCombinerPass(PassRegistry &);
void initializeLoadCombinePass(PassRegistry&);
void initializeRewriteSymbolsPass(PassRegistry&);
void initializeWinEHPreparePass(PassRegistry&);
void initializePlaceBackedgeSafepointsImplPass(PassRegistry&);
void initializePlaceSafepointsPass(PassRegistry&);
void initializeDwarfEHPreparePass(PassRegistry&);
void initializeFloat2IntPass(PassRegistry&);
void initializeLoopDistributePass(PassRegistry&);
void initializeSjLjEHPreparePass(PassRegistry&);
void initializeDemandedBitsPass(PassRegistry&);
void initializeFuncletLayoutPass(PassRegistry &);
void initializeLoopLoadEliminationPass(PassRegistry&);
}
#endif