X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FPasses.cpp;h=6246c21566a07218ede951252f2bf85c8ab6dd6b;hb=5f46eb157e58df285e1a0a7ce6ff1c9ed972bf65;hp=a896f83526e2dfeb590caebff63e41e4691774c6;hpb=9ff542f2cce5bf7bf3cf9f692cf3ec0690ad2b3b;p=oota-llvm.git diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp index a896f83526e..6246c21566a 100644 --- a/lib/CodeGen/Passes.cpp +++ b/lib/CodeGen/Passes.cpp @@ -2,8 +2,8 @@ // // The LLVM Compiler Infrastructure // -// This file was developed by the LLVM research group and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // @@ -12,31 +12,622 @@ // //===---------------------------------------------------------------------===// -#include "llvm/CodeGen/MachinePassRegistry.h" +#include "llvm/Analysis/Passes.h" +#include "llvm/Analysis/Verifier.h" +#include "llvm/Transforms/Scalar.h" +#include "llvm/PassManager.h" +#include "llvm/CodeGen/GCStrategy.h" +#include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/Passes.h" +#include "llvm/CodeGen/RegAllocRegistry.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetOptions.h" +#include "llvm/Assembly/PrintModulePass.h" #include "llvm/Support/CommandLine.h" -#include +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" using namespace llvm; -namespace { - cl::opt > - RegAlloc("regalloc", - cl::init("linearscan"), - cl::desc("Register allocator to use: (default = linearscan)")); +static cl::opt DisablePostRA("disable-post-ra", cl::Hidden, + cl::desc("Disable Post Regalloc")); +static cl::opt DisableBranchFold("disable-branch-fold", cl::Hidden, + cl::desc("Disable branch folding")); +static cl::opt DisableTailDuplicate("disable-tail-duplicate", cl::Hidden, + cl::desc("Disable tail duplication")); +static cl::opt DisableEarlyTailDup("disable-early-taildup", cl::Hidden, + cl::desc("Disable pre-register allocation tail duplication")); +static cl::opt EnableBlockPlacement("enable-block-placement", + cl::Hidden, cl::desc("Enable probability-driven block placement")); +static cl::opt EnableBlockPlacementStats("enable-block-placement-stats", + cl::Hidden, cl::desc("Collect probability-driven block placement stats")); +static cl::opt DisableCodePlace("disable-code-place", cl::Hidden, + cl::desc("Disable code placement")); +static cl::opt DisableSSC("disable-ssc", cl::Hidden, + cl::desc("Disable Stack Slot Coloring")); +static cl::opt DisableMachineDCE("disable-machine-dce", cl::Hidden, + cl::desc("Disable Machine Dead Code Elimination")); +static cl::opt DisableMachineLICM("disable-machine-licm", cl::Hidden, + cl::desc("Disable Machine LICM")); +static cl::opt DisableMachineCSE("disable-machine-cse", cl::Hidden, + cl::desc("Disable Machine Common Subexpression Elimination")); +static cl::opt +OptimizeRegAlloc("optimize-regalloc", cl::Hidden, + cl::desc("Enable optimized register allocation compilation path.")); +static cl::opt +EnableMachineSched("enable-misched", cl::Hidden, + cl::desc("Enable the machine instruction scheduling pass.")); +static cl::opt EnableStrongPHIElim("strong-phi-elim", cl::Hidden, + cl::desc("Use strong PHI elimination.")); +static cl::opt DisablePostRAMachineLICM("disable-postra-machine-licm", + cl::Hidden, + cl::desc("Disable Machine LICM")); +static cl::opt DisableMachineSink("disable-machine-sink", cl::Hidden, + cl::desc("Disable Machine Sinking")); +static cl::opt DisableLSR("disable-lsr", cl::Hidden, + cl::desc("Disable Loop Strength Reduction Pass")); +static cl::opt DisableCGP("disable-cgp", cl::Hidden, + cl::desc("Disable Codegen Prepare")); +static cl::opt DisableCopyProp("disable-copyprop", cl::Hidden, + cl::desc("Disable Copy Propagation pass")); +static cl::opt PrintLSR("print-lsr-output", cl::Hidden, + cl::desc("Print LLVM IR produced by the loop-reduce pass")); +static cl::opt PrintISelInput("print-isel-input", cl::Hidden, + cl::desc("Print LLVM IR input to isel pass")); +static cl::opt PrintGCInfo("print-gc", cl::Hidden, + cl::desc("Dump garbage collector data")); +static cl::opt VerifyMachineCode("verify-machineinstrs", cl::Hidden, + cl::desc("Verify generated machine code"), + cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL)); + +/// Allow standard passes to be disabled by command line options. This supports +/// simple binary flags that either suppress the pass or do nothing. +/// i.e. -disable-mypass=false has no effect. +/// These should be converted to boolOrDefault in order to use applyOverride. +static AnalysisID applyDisable(AnalysisID ID, bool Override) { + if (Override) + return &NoPassID; + return ID; +} + +/// Allow Pass selection to be overriden by command line options. This supports +/// flags with ternary conditions. TargetID is passed through by default. The +/// pass is suppressed when the option is false. When the option is true, the +/// StandardID is selected if the target provides no default. +static AnalysisID applyOverride(AnalysisID TargetID, cl::boolOrDefault Override, + AnalysisID StandardID) { + switch (Override) { + case cl::BOU_UNSET: + return TargetID; + case cl::BOU_TRUE: + if (TargetID != &NoPassID) + return TargetID; + if (StandardID == &NoPassID) + report_fatal_error("Target cannot enable pass"); + return StandardID; + case cl::BOU_FALSE: + return &NoPassID; + } + llvm_unreachable("Invalid command line option state"); +} + +/// Allow standard passes to be disabled by the command line, regardless of who +/// is adding the pass. +/// +/// StandardID is the pass identified in the standard pass pipeline and provided +/// to addPass(). It may be a target-specific ID in the case that the target +/// directly adds its own pass, but in that case we harmlessly fall through. +/// +/// TargetID is the pass that the target has configured to override StandardID. +/// +/// StandardID may be a pseudo ID. In that case TargetID is the name of the real +/// pass to run. This allows multiple options to control a single pass depending +/// on where in the pipeline that pass is added. +static AnalysisID overridePass(AnalysisID StandardID, AnalysisID TargetID) { + if (StandardID == &PostRASchedulerID) + return applyDisable(TargetID, DisablePostRA); + + if (StandardID == &BranchFolderPassID) + return applyDisable(TargetID, DisableBranchFold); + + if (StandardID == &TailDuplicateID) + return applyDisable(TargetID, DisableTailDuplicate); + + if (StandardID == &TargetPassConfig::EarlyTailDuplicateID) + return applyDisable(TargetID, DisableEarlyTailDup); + + if (StandardID == &MachineBlockPlacementID) + return applyDisable(TargetID, DisableCodePlace); + + if (StandardID == &CodePlacementOptID) + return applyDisable(TargetID, DisableCodePlace); + + if (StandardID == &StackSlotColoringID) + return applyDisable(TargetID, DisableSSC); + + if (StandardID == &DeadMachineInstructionElimID) + return applyDisable(TargetID, DisableMachineDCE); + + if (StandardID == &MachineLICMID) + return applyDisable(TargetID, DisableMachineLICM); + + if (StandardID == &MachineCSEID) + return applyDisable(TargetID, DisableMachineCSE); + + if (StandardID == &MachineSchedulerID) + return applyOverride(TargetID, EnableMachineSched, StandardID); + + if (StandardID == &TargetPassConfig::PostRAMachineLICMID) + return applyDisable(TargetID, DisablePostRAMachineLICM); + + if (StandardID == &MachineSinkingID) + return applyDisable(TargetID, DisableMachineSink); + + if (StandardID == &MachineCopyPropagationID) + return applyDisable(TargetID, DisableCopyProp); + + return TargetID; +} + +//===---------------------------------------------------------------------===// +/// TargetPassConfig +//===---------------------------------------------------------------------===// + +INITIALIZE_PASS(TargetPassConfig, "targetpassconfig", + "Target Pass Configuration", false, false) +char TargetPassConfig::ID = 0; + +static char NoPassIDAnchor = 0; +char &llvm::NoPassID = NoPassIDAnchor; + +// Pseudo Pass IDs. +char TargetPassConfig::EarlyTailDuplicateID = 0; +char TargetPassConfig::PostRAMachineLICMID = 0; + +namespace llvm { +class PassConfigImpl { +public: + // List of passes explicitly substituted by this target. Normally this is + // empty, but it is a convenient way to suppress or replace specific passes + // that are part of a standard pass pipeline without overridding the entire + // pipeline. This mechanism allows target options to inherit a standard pass's + // user interface. For example, a target may disable a standard pass by + // default by substituting NoPass, and the user may still enable that standard + // pass with an explicit command line option. + DenseMap TargetPasses; +}; +} // namespace llvm + +// Out of line virtual method. +TargetPassConfig::~TargetPassConfig() { + delete Impl; +} + +// Out of line constructor provides default values for pass options and +// registers all common codegen passes. +TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm) + : ImmutablePass(ID), TM(tm), PM(pm), Impl(0), Initialized(false), + DisableVerify(false), + EnableTailMerge(true) { + + Impl = new PassConfigImpl(); + + // Register all target independent codegen passes to activate their PassIDs, + // including this pass itself. + initializeCodeGen(*PassRegistry::getPassRegistry()); + + // Substitute Pseudo Pass IDs for real ones. + substitutePass(EarlyTailDuplicateID, TailDuplicateID); + substitutePass(PostRAMachineLICMID, MachineLICMID); + + // Temporarily disable experimental passes. + substitutePass(MachineSchedulerID, NoPassID); +} + +/// createPassConfig - Create a pass configuration object to be used by +/// addPassToEmitX methods for generating a pipeline of CodeGen passes. +/// +/// Targets may override this to extend TargetPassConfig. +TargetPassConfig *LLVMTargetMachine::createPassConfig(PassManagerBase &PM) { + return new TargetPassConfig(this, PM); +} + +TargetPassConfig::TargetPassConfig() + : ImmutablePass(ID), PM(*(PassManagerBase*)0) { + llvm_unreachable("TargetPassConfig should not be constructed on-the-fly"); +} + +// Helper to verify the analysis is really immutable. +void TargetPassConfig::setOpt(bool &Opt, bool Val) { + assert(!Initialized && "PassConfig is immutable"); + Opt = Val; +} + +void TargetPassConfig::substitutePass(char &StandardID, char &TargetID) { + Impl->TargetPasses[&StandardID] = &TargetID; +} + +AnalysisID TargetPassConfig::getPassSubstitution(AnalysisID ID) const { + DenseMap::const_iterator + I = Impl->TargetPasses.find(ID); + if (I == Impl->TargetPasses.end()) + return ID; + return I->second; +} + +/// Add a CodeGen pass at this point in the pipeline after checking for target +/// and command line overrides. +AnalysisID TargetPassConfig::addPass(char &ID) { + assert(!Initialized && "PassConfig is immutable"); + + AnalysisID TargetID = getPassSubstitution(&ID); + AnalysisID FinalID = overridePass(&ID, TargetID); + if (FinalID == &NoPassID) + return FinalID; + + Pass *P = Pass::createPass(FinalID); + if (!P) + llvm_unreachable("Pass ID not registered"); + PM.add(P); + return FinalID; +} + +void TargetPassConfig::printNoVerify(const char *Banner) const { + if (TM->shouldPrintMachineCode()) + PM.add(createMachineFunctionPrinterPass(dbgs(), Banner)); } -FunctionPass *llvm::createRegisterAllocator() { +void TargetPassConfig::printAndVerify(const char *Banner) const { + if (TM->shouldPrintMachineCode()) + PM.add(createMachineFunctionPrinterPass(dbgs(), Banner)); + + if (VerifyMachineCode) + PM.add(createMachineVerifierPass(Banner)); +} + +/// Add common target configurable passes that perform LLVM IR to IR transforms +/// following machine independent optimization. +void TargetPassConfig::addIRPasses() { + // Basic AliasAnalysis support. + // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that + // BasicAliasAnalysis wins if they disagree. This is intended to help + // support "obvious" type-punning idioms. + PM.add(createTypeBasedAliasAnalysisPass()); + PM.add(createBasicAliasAnalysisPass()); + + // Before running any passes, run the verifier to determine if the input + // coming from the front-end and/or optimizer is valid. + if (!DisableVerify) + PM.add(createVerifierPass()); + + // Run loop strength reduction before anything else. + if (getOptLevel() != CodeGenOpt::None && !DisableLSR) { + PM.add(createLoopStrengthReducePass(getTargetLowering())); + if (PrintLSR) + PM.add(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &dbgs())); + } + + PM.add(createGCLoweringPass()); + + // Make sure that no unreachable blocks are instruction selected. + PM.add(createUnreachableBlockEliminationPass()); +} + +/// Add common passes that perform LLVM IR to IR transforms in preparation for +/// instruction selection. +void TargetPassConfig::addISelPrepare() { + if (getOptLevel() != CodeGenOpt::None && !DisableCGP) + PM.add(createCodeGenPreparePass(getTargetLowering())); + + PM.add(createStackProtectorPass(getTargetLowering())); + + addPreISel(); + + if (PrintISelInput) + PM.add(createPrintFunctionPass("\n\n" + "*** Final LLVM Code input to ISel ***\n", + &dbgs())); + + // All passes which modify the LLVM IR are now complete; run the verifier + // to ensure that the IR is valid. + if (!DisableVerify) + PM.add(createVerifierPass()); +} + +/// Add the complete set of target-independent postISel code generator passes. +/// +/// This can be read as the standard order of major LLVM CodeGen stages. Stages +/// with nontrivial configuration or multiple passes are broken out below in +/// add%Stage routines. +/// +/// Any TargetPassConfig::addXX routine may be overriden by the Target. The +/// addPre/Post methods with empty header implementations allow injecting +/// target-specific fixups just before or after major stages. Additionally, +/// targets have the flexibility to change pass order within a stage by +/// overriding default implementation of add%Stage routines below. Each +/// technique has maintainability tradeoffs because alternate pass orders are +/// not well supported. addPre/Post works better if the target pass is easily +/// tied to a common pass. But if it has subtle dependencies on multiple passes, +/// the target should override the stage instead. +/// +/// TODO: We could use a single addPre/Post(ID) hook to allow pass injection +/// before/after any target-independent pass. But it's currently overkill. +void TargetPassConfig::addMachinePasses() { + // Print the instruction selected machine code... + printAndVerify("After Instruction Selection"); + + // Expand pseudo-instructions emitted by ISel. + addPass(ExpandISelPseudosID); + + // Add passes that optimize machine instructions in SSA form. + if (getOptLevel() != CodeGenOpt::None) { + addMachineSSAOptimization(); + } + else { + // If the target requests it, assign local variables to stack slots relative + // to one another and simplify frame index references where possible. + addPass(LocalStackSlotAllocationID); + } + + // Run pre-ra passes. + if (addPreRegAlloc()) + printAndVerify("After PreRegAlloc passes"); + + // Run register allocation and passes that are tightly coupled with it, + // including phi elimination and scheduling. + if (getOptimizeRegAlloc()) + addOptimizedRegAlloc(createRegAllocPass(true)); + else + addFastRegAlloc(createRegAllocPass(false)); + + // Run post-ra passes. + if (addPostRegAlloc()) + printAndVerify("After PostRegAlloc passes"); + + // Insert prolog/epilog code. Eliminate abstract frame index references... + addPass(PrologEpilogCodeInserterID); + printAndVerify("After PrologEpilogCodeInserter"); + + /// Add passes that optimize machine instructions after register allocation. + if (getOptLevel() != CodeGenOpt::None) + addMachineLateOptimization(); + + // Expand pseudo instructions before second scheduling pass. + addPass(ExpandPostRAPseudosID); + printNoVerify("After ExpandPostRAPseudos"); + + // Run pre-sched2 passes. + if (addPreSched2()) + printNoVerify("After PreSched2 passes"); + + // Second pass scheduler. + if (getOptLevel() != CodeGenOpt::None) { + addPass(PostRASchedulerID); + printNoVerify("After PostRAScheduler"); + } + + // GC + addPass(GCMachineCodeAnalysisID); + if (PrintGCInfo) + PM.add(createGCInfoPrinter(dbgs())); + + // Basic block placement. + if (getOptLevel() != CodeGenOpt::None) + addBlockPlacement(); + + if (addPreEmitPass()) + printNoVerify("After PreEmit passes"); +} + +/// Add passes that optimize machine instructions in SSA form. +void TargetPassConfig::addMachineSSAOptimization() { + // Pre-ra tail duplication. + if (addPass(EarlyTailDuplicateID) != &NoPassID) + printAndVerify("After Pre-RegAlloc TailDuplicate"); + + // Optimize PHIs before DCE: removing dead PHI cycles may make more + // instructions dead. + addPass(OptimizePHIsID); + + // If the target requests it, assign local variables to stack slots relative + // to one another and simplify frame index references where possible. + addPass(LocalStackSlotAllocationID); + + // With optimization, dead code should already be eliminated. However + // there is one known exception: lowered code for arguments that are only + // used by tail calls, where the tail calls reuse the incoming stack + // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll). + addPass(DeadMachineInstructionElimID); + printAndVerify("After codegen DCE pass"); + + addPass(MachineLICMID); + addPass(MachineCSEID); + addPass(MachineSinkingID); + printAndVerify("After Machine LICM, CSE and Sinking passes"); + + addPass(PeepholeOptimizerID); + printAndVerify("After codegen peephole optimization pass"); +} + +//===---------------------------------------------------------------------===// +/// Register Allocation Pass Configuration +//===---------------------------------------------------------------------===// + +bool TargetPassConfig::getOptimizeRegAlloc() const { + switch (OptimizeRegAlloc) { + case cl::BOU_UNSET: return getOptLevel() != CodeGenOpt::None; + case cl::BOU_TRUE: return true; + case cl::BOU_FALSE: return false; + } + llvm_unreachable("Invalid optimize-regalloc state"); +} + +/// RegisterRegAlloc's global Registry tracks allocator registration. +MachinePassRegistry RegisterRegAlloc::Registry; + +/// A dummy default pass factory indicates whether the register allocator is +/// overridden on the command line. +static FunctionPass *useDefaultRegisterAllocator() { return 0; } +static RegisterRegAlloc +defaultRegAlloc("default", + "pick register allocator based on -O option", + useDefaultRegisterAllocator); + +/// -regalloc=... command line option. +static cl::opt > +RegAlloc("regalloc", + cl::init(&useDefaultRegisterAllocator), + cl::desc("Register allocator to use")); + + +/// Instantiate the default register allocator pass for this target for either +/// the optimized or unoptimized allocation path. This will be added to the pass +/// manager by addFastRegAlloc in the unoptimized case or addOptimizedRegAlloc +/// in the optimized case. +/// +/// A target that uses the standard regalloc pass order for fast or optimized +/// allocation may still override this for per-target regalloc +/// selection. But -regalloc=... always takes precedence. +FunctionPass *TargetPassConfig::createTargetRegisterAllocator(bool Optimized) { + if (Optimized) + return createGreedyRegisterAllocator(); + else + return createFastRegisterAllocator(); +} + +/// Find and instantiate the register allocation pass requested by this target +/// at the current optimization level. Different register allocators are +/// defined as separate passes because they may require different analysis. +/// +/// This helper ensures that the regalloc= option is always available, +/// even for targets that override the default allocator. +/// +/// FIXME: When MachinePassRegistry register pass IDs instead of function ptrs, +/// this can be folded into addPass. +FunctionPass *TargetPassConfig::createRegAllocPass(bool Optimized) { RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault(); - + + // Initialize the global default. if (!Ctor) { - Ctor = RegisterRegAlloc::FindCtor(RegAlloc); - assert(Ctor && "No register allocator found"); - if (!Ctor) Ctor = RegisterRegAlloc::FirstCtor(); - RegisterRegAlloc::setDefault(Ctor); - } - - assert(Ctor && "No register allocator found"); - - return Ctor(); + Ctor = RegAlloc; + RegisterRegAlloc::setDefault(RegAlloc); + } + if (Ctor != useDefaultRegisterAllocator) + return Ctor(); + + // With no -regalloc= override, ask the target for a regalloc pass. + return createTargetRegisterAllocator(Optimized); +} + +/// Add the minimum set of target-independent passes that are required for +/// register allocation. No coalescing or scheduling. +void TargetPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) { + addPass(PHIEliminationID); + addPass(TwoAddressInstructionPassID); + + PM.add(RegAllocPass); + printAndVerify("After Register Allocation"); +} + +/// Add standard target-independent passes that are tightly coupled with +/// optimized register allocation, including coalescing, machine instruction +/// scheduling, and register allocation itself. +void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) { + // LiveVariables currently requires pure SSA form. + // + // FIXME: Once TwoAddressInstruction pass no longer uses kill flags, + // LiveVariables can be removed completely, and LiveIntervals can be directly + // computed. (We still either need to regenerate kill flags after regalloc, or + // preferably fix the scavenger to not depend on them). + addPass(LiveVariablesID); + + // Add passes that move from transformed SSA into conventional SSA. This is a + // "copy coalescing" problem. + // + if (!EnableStrongPHIElim) { + // Edge splitting is smarter with machine loop info. + addPass(MachineLoopInfoID); + addPass(PHIEliminationID); + } + addPass(TwoAddressInstructionPassID); + + // FIXME: Either remove this pass completely, or fix it so that it works on + // SSA form. We could modify LiveIntervals to be independent of this pass, But + // it would be even better to simply eliminate *all* IMPLICIT_DEFs before + // leaving SSA. + addPass(ProcessImplicitDefsID); + + if (EnableStrongPHIElim) + addPass(StrongPHIEliminationID); + + addPass(RegisterCoalescerID); + + // PreRA instruction scheduling. + if (addPass(MachineSchedulerID) != &NoPassID) + printAndVerify("After Machine Scheduling"); + + // Add the selected register allocation pass. + PM.add(RegAllocPass); + printAndVerify("After Register Allocation"); + + // FinalizeRegAlloc is convenient until MachineInstrBundles is more mature, + // but eventually, all users of it should probably be moved to addPostRA and + // it can go away. Currently, it's the intended place for targets to run + // FinalizeMachineBundles, because passes other than MachineScheduling an + // RegAlloc itself may not be aware of bundles. + if (addFinalizeRegAlloc()) + printAndVerify("After RegAlloc finalization"); + + // Perform stack slot coloring and post-ra machine LICM. + // + // FIXME: Re-enable coloring with register when it's capable of adding + // kill markers. + addPass(StackSlotColoringID); + + // Run post-ra machine LICM to hoist reloads / remats. + // + // FIXME: can this move into MachineLateOptimization? + addPass(PostRAMachineLICMID); + + printAndVerify("After StackSlotColoring and postra Machine LICM"); +} + +//===---------------------------------------------------------------------===// +/// Post RegAlloc Pass Configuration +//===---------------------------------------------------------------------===// + +/// Add passes that optimize machine instructions after register allocation. +void TargetPassConfig::addMachineLateOptimization() { + // Branch folding must be run after regalloc and prolog/epilog insertion. + if (addPass(BranchFolderPassID) != &NoPassID) + printNoVerify("After BranchFolding"); + + // Tail duplication. + if (addPass(TailDuplicateID) != &NoPassID) + printNoVerify("After TailDuplicate"); + + // Copy propagation. + if (addPass(MachineCopyPropagationID) != &NoPassID) + printNoVerify("After copy propagation pass"); +} + +/// Add standard basic block placement passes. +void TargetPassConfig::addBlockPlacement() { + AnalysisID ID = &NoPassID; + if (EnableBlockPlacement) { + // MachineBlockPlacement is an experimental pass which is disabled by + // default currently. Eventually it should subsume CodePlacementOpt, so + // when enabled, the other is disabled. + ID = addPass(MachineBlockPlacementID); + } else { + ID = addPass(CodePlacementOptID); + } + if (ID != &NoPassID) { + // Run a separate pass to collect block placement statistics. + if (EnableBlockPlacementStats) + addPass(MachineBlockPlacementStatsID); + + printNoVerify("After machine block placement."); + } }