45e666a853
Clang isn't able to support multiple constraints on inputs and outputs,
like "rm". Instead, it picks the "safest" one to use, i.e. the memory
constraint for "rm". This leads to obviously horrible code:
asm __volatile__ ("pushf\n\t"
"popq %0"
: "=rm" (x));
is compiled to:
pushf
popq -8(%rsp)
movq -8(%rsp), %rax
It gets worse when inlined into other functions, because it may
introduce
a stack where none is needed.
With this change, Clang now generates IR for the more optimistic choice
("r"). All but the fast register allocator are able to fold registers if
it turns out that register pressure is too high.
This leaves the fast register allocator. The fast register allocator, as
the name suggests, is built for execution speed, not code quality. Thus,
we add special processing to convert the "optimistic" IR into the
"conservative" choice (again at the IR level), which we know it can
handle.
We focus on "rm" for the initial commit, but that can be expanded in the
future for other constraints where Clang generates ++ungood code (like
"g").
Fixes: https://github.com/llvm/llvm-project/issues/20571
173 lines
8.1 KiB
C++
173 lines
8.1 KiB
C++
//===-- CodeGen.cpp -------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the common initialization routines for the
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// CodeGen library.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/InitializePasses.h"
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#include "llvm/PassRegistry.h"
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using namespace llvm;
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/// initializeCodeGen - Initialize all passes linked into the CodeGen library.
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void llvm::initializeCodeGen(PassRegistry &Registry) {
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initializeAssignmentTrackingAnalysisPass(Registry);
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initializeAtomicExpandLegacyPass(Registry);
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initializeBasicBlockMatchingAndInferencePass(Registry);
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initializeBasicBlockPathCloningPass(Registry);
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initializeBasicBlockSectionsPass(Registry);
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initializeBasicBlockSectionsProfileReaderWrapperPassPass(Registry);
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initializeBranchFolderLegacyPass(Registry);
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initializeBranchRelaxationLegacyPass(Registry);
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initializeBreakFalseDepsPass(Registry);
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initializeCFGuardLongjmpPass(Registry);
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initializeCFIFixupPass(Registry);
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initializeCFIInstrInserterPass(Registry);
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initializeCheckDebugMachineModulePass(Registry);
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initializeCodeGenPrepareLegacyPassPass(Registry);
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initializeComplexDeinterleavingLegacyPassPass(Registry);
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initializeDeadMachineInstructionElimPass(Registry);
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initializeDebugifyMachineModulePass(Registry);
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initializeDetectDeadLanesLegacyPass(Registry);
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initializeDummyCGSCCPassPass(Registry);
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initializeDwarfEHPrepareLegacyPassPass(Registry);
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initializeEHContGuardTargetsPass(Registry);
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initializeEarlyIfConverterLegacyPass(Registry);
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initializeEarlyIfPredicatorPass(Registry);
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initializeEarlyMachineLICMPass(Registry);
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initializeEarlyTailDuplicateLegacyPass(Registry);
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initializeExpandIRInstsLegacyPassPass(Registry);
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initializeExpandMemCmpLegacyPassPass(Registry);
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initializeExpandPostRALegacyPass(Registry);
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initializeExpandReductionsPass(Registry);
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initializeFEntryInserterLegacyPass(Registry);
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initializeFinalizeISelPass(Registry);
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initializeFixupStatepointCallerSavedLegacyPass(Registry);
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initializeFuncletLayoutPass(Registry);
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initializeGCEmptyBasicBlocksLegacyPass(Registry);
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initializeGCMachineCodeAnalysisPass(Registry);
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initializeGCModuleInfoPass(Registry);
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initializeGlobalMergePass(Registry);
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initializeGlobalMergeFuncPassWrapperPass(Registry);
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initializeHardwareLoopsLegacyPass(Registry);
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initializeIfConverterPass(Registry);
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initializeImplicitNullChecksPass(Registry);
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initializeIndirectBrExpandLegacyPassPass(Registry);
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initializeInsertCodePrefetchPass(Registry);
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initializeInitUndefLegacyPass(Registry);
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initializeInlineAsmPreparePass(Registry);
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initializeInterleavedLoadCombinePass(Registry);
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initializeInterleavedAccessPass(Registry);
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initializeJMCInstrumenterPass(Registry);
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initializeLazyMachineBlockFrequencyInfoPassPass(Registry);
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initializeLibcallLoweringInfoWrapperPass(Registry);
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initializeLiveDebugValuesLegacyPass(Registry);
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initializeLiveDebugVariablesWrapperLegacyPass(Registry);
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initializeLiveIntervalsWrapperPassPass(Registry);
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initializeLiveRangeShrinkPass(Registry);
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initializeLiveStacksWrapperLegacyPass(Registry);
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initializeLiveVariablesWrapperPassPass(Registry);
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initializeLocalStackSlotPassPass(Registry);
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initializeLowerEmuTLSPass(Registry);
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initializeLowerGlobalDtorsLegacyPassPass(Registry);
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initializeLowerIntrinsicsPass(Registry);
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initializeMIRAddFSDiscriminatorsPass(Registry);
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initializeMIRCanonicalizerPass(Registry);
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initializeMIRNamerPass(Registry);
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initializeMIRProfileLoaderPassPass(Registry);
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initializeMachineBlockFrequencyInfoWrapperPassPass(Registry);
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initializeMachineBlockHashInfoPass(Registry);
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initializeMachineBlockPlacementLegacyPass(Registry);
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initializeMachineBlockPlacementStatsLegacyPass(Registry);
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initializeMachineBranchProbabilityInfoWrapperPassPass(Registry);
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initializeMachineCFGPrinterPass(Registry);
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initializeMachineCSELegacyPass(Registry);
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initializeMachineCombinerPass(Registry);
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initializeMachineDominanceFrontierWrapperPassPass(Registry);
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initializeMachineCopyPropagationLegacyPass(Registry);
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initializeMachineCycleInfoPrinterLegacyPass(Registry);
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initializeMachineCycleInfoWrapperPassPass(Registry);
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initializeMachineDominatorTreeWrapperPassPass(Registry);
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initializeMachineFunctionPrinterPassPass(Registry);
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initializeMachineFunctionSplitterPass(Registry);
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initializeMachineLateInstrsCleanupLegacyPass(Registry);
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initializeMachineLICMPass(Registry);
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initializeMachineLoopInfoWrapperPassPass(Registry);
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initializeMachineModuleInfoWrapperPassPass(Registry);
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initializeMachineOptimizationRemarkEmitterPassPass(Registry);
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initializeMachineOutlinerPass(Registry);
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initializeMachinePipelinerPass(Registry);
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initializeMachineSanitizerBinaryMetadataLegacyPass(Registry);
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initializeModuloScheduleTestPass(Registry);
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initializeMachinePostDominatorTreeWrapperPassPass(Registry);
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initializeMachineRegionInfoPassPass(Registry);
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initializeMachineSchedulerLegacyPass(Registry);
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initializeMachineSinkingLegacyPass(Registry);
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initializeMachineUniformityAnalysisPassPass(Registry);
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initializeMIR2VecVocabLegacyAnalysisPass(Registry);
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initializeMIR2VecVocabPrinterLegacyPassPass(Registry);
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initializeMIR2VecPrinterLegacyPassPass(Registry);
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initializeMachineUniformityInfoPrinterPassPass(Registry);
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initializeMachineVerifierLegacyPassPass(Registry);
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initializeObjCARCContractLegacyPassPass(Registry);
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initializeOptimizePHIsLegacyPass(Registry);
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initializePEILegacyPass(Registry);
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initializePHIEliminationPass(Registry);
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initializePatchableFunctionLegacyPass(Registry);
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initializePeepholeOptimizerLegacyPass(Registry);
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initializePhysicalRegisterUsageInfoWrapperLegacyPass(Registry);
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initializePostMachineSchedulerLegacyPass(Registry);
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initializePostRAMachineSinkingLegacyPass(Registry);
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initializePostRAHazardRecognizerLegacyPass(Registry);
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initializePostRASchedulerLegacyPass(Registry);
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initializePreISelIntrinsicLoweringLegacyPassPass(Registry);
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initializeProcessImplicitDefsLegacyPass(Registry);
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initializePseudoProbeInserterPass(Registry);
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initializeRABasicPass(Registry);
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initializeRAGreedyLegacyPass(Registry);
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initializeReachingDefInfoWrapperPassPass(Registry);
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initializeRegAllocFastPass(Registry);
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initializeRegAllocScoringPass(Registry);
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initializeRegUsageInfoCollectorLegacyPass(Registry);
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initializeRegUsageInfoPropagationLegacyPass(Registry);
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initializeRegisterCoalescerLegacyPass(Registry);
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initializeRemoveLoadsIntoFakeUsesLegacyPass(Registry);
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initializeRemoveRedundantDebugValuesLegacyPass(Registry);
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initializeRenameIndependentSubregsLegacyPass(Registry);
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initializeReplaceWithVeclibLegacyPass(Registry);
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initializeSafeStackLegacyPassPass(Registry);
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initializeSelectOptimizePass(Registry);
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initializeShadowStackGCLoweringPass(Registry);
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initializeShrinkWrapLegacyPass(Registry);
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initializeSjLjEHPreparePass(Registry);
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initializeSlotIndexesWrapperPassPass(Registry);
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initializeStackColoringLegacyPass(Registry);
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initializeStackFrameLayoutAnalysisLegacyPass(Registry);
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initializeStackMapLivenessPass(Registry);
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initializeStackProtectorPass(Registry);
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initializeStackSlotColoringLegacyPass(Registry);
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initializeStaticDataSplitterPass(Registry);
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initializeStaticDataAnnotatorPass(Registry);
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initializeStripDebugMachineModulePass(Registry);
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initializeTailDuplicateLegacyPass(Registry);
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initializeTargetPassConfigPass(Registry);
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initializeTwoAddressInstructionLegacyPassPass(Registry);
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initializeTypePromotionLegacyPass(Registry);
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initializeUnpackMachineBundlesPass(Registry);
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initializeUnreachableBlockElimLegacyPassPass(Registry);
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initializeUnreachableMachineBlockElimLegacyPass(Registry);
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initializeVirtRegMapWrapperLegacyPass(Registry);
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initializeVirtRegRewriterLegacyPass(Registry);
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initializeWasmEHPreparePass(Registry);
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initializeWinEHPreparePass(Registry);
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initializeWindowsSecureHotPatchingPass(Registry);
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initializeXRayInstrumentationLegacyPass(Registry);
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}
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