X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FCodeGen%2FPasses.cpp;h=319c2c865039829f05a43a91c9410a6f7f78010a;hp=20a3ff45e850d45eb9fb9bf0f8f3f2bcb1950281;hb=dcd3cbea545253df6ba196e3a66decf06fc3f88d;hpb=6b2bb15bf7c77918adc433646846f6847d421257 diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp index 20a3ff45e85..319c2c86503 100644 --- a/lib/CodeGen/Passes.cpp +++ b/lib/CodeGen/Passes.cpp @@ -12,21 +12,21 @@ // //===---------------------------------------------------------------------===// +#include "llvm/CodeGen/Passes.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/IR/IRPrintingPasses.h" +#include "llvm/IR/Verifier.h" #include "llvm/MC/MCAsmInfo.h" -#include "llvm/Assembly/PrintModulePass.h" +#include "llvm/PassManager.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetSubtargetInfo.h" +#include "llvm/Transforms/Scalar.h" using namespace llvm; @@ -39,16 +39,15 @@ static cl::opt DisableTailDuplicate("disable-tail-duplicate", cl::Hidden, static cl::opt DisableEarlyTailDup("disable-early-taildup", cl::Hidden, cl::desc("Disable pre-register allocation tail duplication")); static cl::opt DisableBlockPlacement("disable-block-placement", - cl::Hidden, cl::desc("Disable the probability-driven block placement, and " - "re-enable the old code placement pass")); + cl::Hidden, cl::desc("Disable 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 DisableEarlyIfConversion("disable-early-ifcvt", cl::Hidden, + cl::desc("Disable Early If-conversion")); static cl::opt DisableMachineLICM("disable-machine-licm", cl::Hidden, cl::desc("Disable Machine LICM")); static cl::opt DisableMachineCSE("disable-machine-cse", cl::Hidden, @@ -57,10 +56,8 @@ static cl::opt OptimizeRegAlloc("optimize-regalloc", cl::Hidden, cl::desc("Enable optimized register allocation compilation path.")); static cl::opt -EnableMachineSched("enable-misched", cl::Hidden, +EnableMachineSched("enable-misched", 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")); @@ -68,10 +65,14 @@ 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 DisableConstantHoisting("disable-constant-hoisting", + cl::Hidden, cl::desc("Disable ConstantHoisting")); 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 DisablePartialLibcallInlining("disable-partial-libcall-inlining", + cl::Hidden, cl::desc("Disable Partial Libcall Inlining")); 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, @@ -80,19 +81,32 @@ 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)); + cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=nullptr)); static cl::opt PrintMachineInstrs("print-machineinstrs", cl::ValueOptional, cl::desc("Print machine instrs"), cl::value_desc("pass-name"), cl::init("option-unspecified")); +// Temporary option to allow experimenting with MachineScheduler as a post-RA +// scheduler. Targets can "properly" enable this with +// substitutePass(&PostRASchedulerID, &PostMachineSchedulerID); Ideally it +// wouldn't be part of the standard pass pipeline, and the target would just add +// a PostRA scheduling pass wherever it wants. +static cl::opt MISchedPostRA("misched-postra", cl::Hidden, + cl::desc("Run MachineScheduler post regalloc (independent of preRA sched)")); + +// Experimental option to run live interval analysis early. +static cl::opt EarlyLiveIntervals("early-live-intervals", cl::Hidden, + cl::desc("Run live interval analysis earlier in the pipeline")); + /// 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 PassID, bool Override) { +static IdentifyingPassPtr applyDisable(IdentifyingPassPtr PassID, + bool Override) { if (Override) - return 0; + return IdentifyingPassPtr(); return PassID; } @@ -100,19 +114,20 @@ static AnalysisID applyDisable(AnalysisID PassID, bool Override) { /// 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) { +static IdentifyingPassPtr applyOverride(IdentifyingPassPtr TargetID, + cl::boolOrDefault Override, + AnalysisID StandardID) { switch (Override) { case cl::BOU_UNSET: return TargetID; case cl::BOU_TRUE: - if (TargetID) + if (TargetID.isValid()) return TargetID; - if (StandardID == 0) + if (StandardID == nullptr) report_fatal_error("Target cannot enable pass"); return StandardID; case cl::BOU_FALSE: - return 0; + return IdentifyingPassPtr(); } llvm_unreachable("Invalid command line option state"); } @@ -129,7 +144,8 @@ static AnalysisID applyOverride(AnalysisID TargetID, cl::boolOrDefault Override, /// 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) { +static IdentifyingPassPtr overridePass(AnalysisID StandardID, + IdentifyingPassPtr TargetID) { if (StandardID == &PostRASchedulerID) return applyDisable(TargetID, DisablePostRA); @@ -143,10 +159,7 @@ static AnalysisID overridePass(AnalysisID StandardID, AnalysisID TargetID) { return applyDisable(TargetID, DisableEarlyTailDup); if (StandardID == &MachineBlockPlacementID) - return applyDisable(TargetID, DisableCodePlace); - - if (StandardID == &CodePlacementOptID) - return applyDisable(TargetID, DisableCodePlace); + return applyDisable(TargetID, DisableBlockPlacement); if (StandardID == &StackSlotColoringID) return applyDisable(TargetID, DisableSSC); @@ -154,6 +167,9 @@ static AnalysisID overridePass(AnalysisID StandardID, AnalysisID TargetID) { if (StandardID == &DeadMachineInstructionElimID) return applyDisable(TargetID, DisableMachineDCE); + if (StandardID == &EarlyIfConverterID) + return applyDisable(TargetID, DisableEarlyIfConversion); + if (StandardID == &MachineLICMID) return applyDisable(TargetID, DisableMachineLICM); @@ -197,11 +213,11 @@ public: // user interface. For example, a target may disable a standard pass by // default by substituting a pass ID of zero, and the user may still enable // that standard pass with an explicit command line option. - DenseMap TargetPasses; + DenseMap TargetPasses; /// Store the pairs of of which the second pass /// is inserted after each instance of the first one. - SmallVector, 4> InsertedPasses; + SmallVector, 4> InsertedPasses; }; } // namespace llvm @@ -213,7 +229,8 @@ TargetPassConfig::~TargetPassConfig() { // Out of line constructor provides default values for pass options and // registers all common codegen passes. TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm) - : ImmutablePass(ID), PM(&pm), TM(tm), Impl(0), Initialized(false), + : ImmutablePass(ID), PM(&pm), StartAfter(nullptr), StopAfter(nullptr), + Started(true), Stopped(false), TM(tm), Impl(nullptr), Initialized(false), DisableVerify(false), EnableTailMerge(true) { @@ -228,14 +245,20 @@ TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm) substitutePass(&PostRAMachineLICMID, &MachineLICMID); // Temporarily disable experimental passes. - substitutePass(&MachineSchedulerID, 0); + const TargetSubtargetInfo &ST = TM->getSubtarget(); + if (!ST.useMachineScheduler()) + disablePass(&MachineSchedulerID); } /// Insert InsertedPassID pass after TargetPassID. void TargetPassConfig::insertPass(AnalysisID TargetPassID, - AnalysisID InsertedPassID) { - assert(TargetPassID != InsertedPassID && "Insert a pass after itself!"); - std::pair P(TargetPassID, InsertedPassID); + IdentifyingPassPtr InsertedPassID) { + assert(((!InsertedPassID.isInstance() && + TargetPassID != InsertedPassID.getID()) || + (InsertedPassID.isInstance() && + TargetPassID != InsertedPassID.getInstance()->getPassID())) && + "Insert a pass after itself!"); + std::pair P(TargetPassID, InsertedPassID); Impl->InsertedPasses.push_back(P); } @@ -248,7 +271,7 @@ TargetPassConfig *LLVMTargetMachine::createPassConfig(PassManagerBase &PM) { } TargetPassConfig::TargetPassConfig() - : ImmutablePass(ID), PM(0) { + : ImmutablePass(ID), PM(nullptr) { llvm_unreachable("TargetPassConfig should not be constructed on-the-fly"); } @@ -259,45 +282,79 @@ void TargetPassConfig::setOpt(bool &Opt, bool Val) { } void TargetPassConfig::substitutePass(AnalysisID StandardID, - AnalysisID TargetID) { + IdentifyingPassPtr TargetID) { Impl->TargetPasses[StandardID] = TargetID; } -AnalysisID TargetPassConfig::getPassSubstitution(AnalysisID ID) const { - DenseMap::const_iterator +IdentifyingPassPtr 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 pass to the PassManager. +/// Add a pass to the PassManager if that pass is supposed to be run. If the +/// Started/Stopped flags indicate either that the compilation should start at +/// a later pass or that it should stop after an earlier pass, then do not add +/// the pass. Finally, compare the current pass against the StartAfter +/// and StopAfter options and change the Started/Stopped flags accordingly. void TargetPassConfig::addPass(Pass *P) { assert(!Initialized && "PassConfig is immutable"); - PM->add(P); + // Cache the Pass ID here in case the pass manager finds this pass is + // redundant with ones already scheduled / available, and deletes it. + // Fundamentally, once we add the pass to the manager, we no longer own it + // and shouldn't reference it. + AnalysisID PassID = P->getPassID(); + + if (Started && !Stopped) + PM->add(P); + else + delete P; + if (StopAfter == PassID) + Stopped = true; + if (StartAfter == PassID) + Started = true; + if (Stopped && !Started) + report_fatal_error("Cannot stop compilation after pass that is not run"); } /// Add a CodeGen pass at this point in the pipeline after checking for target /// and command line overrides. +/// +/// addPass cannot return a pointer to the pass instance because is internal the +/// PassManager and the instance we create here may already be freed. AnalysisID TargetPassConfig::addPass(AnalysisID PassID) { - AnalysisID TargetID = getPassSubstitution(PassID); - AnalysisID FinalID = overridePass(PassID, TargetID); - if (FinalID == 0) - return FinalID; - - Pass *P = Pass::createPass(FinalID); - if (!P) - llvm_unreachable("Pass ID not registered"); - addPass(P); + IdentifyingPassPtr TargetID = getPassSubstitution(PassID); + IdentifyingPassPtr FinalPtr = overridePass(PassID, TargetID); + if (!FinalPtr.isValid()) + return nullptr; + + Pass *P; + if (FinalPtr.isInstance()) + P = FinalPtr.getInstance(); + else { + P = Pass::createPass(FinalPtr.getID()); + if (!P) + llvm_unreachable("Pass ID not registered"); + } + AnalysisID FinalID = P->getPassID(); + addPass(P); // Ends the lifetime of P. + // Add the passes after the pass P if there is any. - for (SmallVector, 4>::iterator + for (SmallVectorImpl >::iterator I = Impl->InsertedPasses.begin(), E = Impl->InsertedPasses.end(); I != E; ++I) { if ((*I).first == PassID) { - assert((*I).second && "Illegal Pass ID!"); - Pass *NP = Pass::createPass((*I).second); - assert(NP && "Pass ID not registered"); + assert((*I).second.isValid() && "Illegal Pass ID!"); + Pass *NP; + if ((*I).second.isInstance()) + NP = (*I).second.getInstance(); + else { + NP = Pass::createPass((*I).second.getID()); + assert(NP && "Pass ID not registered"); + } addPass(NP); } } @@ -320,24 +377,34 @@ void TargetPassConfig::addIRPasses() { // BasicAliasAnalysis wins if they disagree. This is intended to help // support "obvious" type-punning idioms. addPass(createTypeBasedAliasAnalysisPass()); + addPass(createScopedNoAliasAAPass()); addPass(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) + if (!DisableVerify) { addPass(createVerifierPass()); + addPass(createDebugInfoVerifierPass()); + } // Run loop strength reduction before anything else. if (getOptLevel() != CodeGenOpt::None && !DisableLSR) { - addPass(createLoopStrengthReducePass(getTargetLowering())); + addPass(createLoopStrengthReducePass()); if (PrintLSR) - addPass(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &dbgs())); + addPass(createPrintFunctionPass(dbgs(), "\n\n*** Code after LSR ***\n")); } addPass(createGCLoweringPass()); // Make sure that no unreachable blocks are instruction selected. addPass(createUnreachableBlockEliminationPass()); + + // Prepare expensive constants for SelectionDAG. + if (getOptLevel() != CodeGenOpt::None && !DisableConstantHoisting) + addPass(createConstantHoistingPass()); + + if (getOptLevel() != CodeGenOpt::None && !DisablePartialLibcallInlining) + addPass(createPartiallyInlineLibCallsPass()); } /// Turn exception handling constructs into something the code generators can @@ -351,15 +418,15 @@ void TargetPassConfig::addPassesToHandleExceptions() { // removed from the parent invoke(s). This could happen when a landing // pad is shared by multiple invokes and is also a target of a normal // edge from elsewhere. - addPass(createSjLjEHPreparePass(TM->getTargetLowering())); + addPass(createSjLjEHPreparePass(TM)); // FALLTHROUGH case ExceptionHandling::DwarfCFI: case ExceptionHandling::ARM: - case ExceptionHandling::Win64: + case ExceptionHandling::WinEH: addPass(createDwarfEHPass(TM)); break; case ExceptionHandling::None: - addPass(createLowerInvokePass(TM->getTargetLowering())); + addPass(createLowerInvokePass()); // The lower invoke pass may create unreachable code. Remove it. addPass(createUnreachableBlockEliminationPass()); @@ -367,20 +434,29 @@ void TargetPassConfig::addPassesToHandleExceptions() { } } +/// Add pass to prepare the LLVM IR for code generation. This should be done +/// before exception handling preparation passes. +void TargetPassConfig::addCodeGenPrepare() { + if (getOptLevel() != CodeGenOpt::None && !DisableCGP) + addPass(createCodeGenPreparePass(TM)); +} + /// Add common passes that perform LLVM IR to IR transforms in preparation for /// instruction selection. void TargetPassConfig::addISelPrepare() { - if (getOptLevel() != CodeGenOpt::None && !DisableCGP) - addPass(createCodeGenPreparePass(getTargetLowering())); + addPreISel(); - addPass(createStackProtectorPass(getTargetLowering())); + // Need to verify DebugInfo *before* creating the stack protector analysis. + // It's a function pass, and verifying between it and its users causes a + // crash. + if (!DisableVerify) + addPass(createDebugInfoVerifierPass()); - addPreISel(); + addPass(createStackProtectorPass(TM)); if (PrintISelInput) - addPass(createPrintFunctionPass("\n\n" - "*** Final LLVM Code input to ISel ***\n", - &dbgs())); + addPass(createPrintFunctionPass( + dbgs(), "\n\n*** Final LLVM Code input to ISel ***\n")); // All passes which modify the LLVM IR are now complete; run the verifier // to ensure that the IR is valid. @@ -407,9 +483,6 @@ void TargetPassConfig::addISelPrepare() { /// 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"); - // Insert a machine instr printer pass after the specified pass. // If -print-machineinstrs specified, print machineinstrs after all passes. if (StringRef(PrintMachineInstrs.getValue()).equals("")) @@ -420,19 +493,22 @@ void TargetPassConfig::addMachinePasses() { const PassInfo *TPI = PR->getPassInfo(PrintMachineInstrs.getValue()); const PassInfo *IPI = PR->getPassInfo(StringRef("print-machineinstrs")); assert (TPI && IPI && "Pass ID not registered!"); - const char *TID = (char *)(TPI->getTypeInfo()); - const char *IID = (char *)(IPI->getTypeInfo()); + const char *TID = (const char *)(TPI->getTypeInfo()); + const char *IID = (const char *)(IPI->getTypeInfo()); insertPass(TID, IID); } + // Print the instruction selected machine code... + printAndVerify("After Instruction Selection"); + // Expand pseudo-instructions emitted by ISel. - addPass(&ExpandISelPseudosID); + if (addPass(&ExpandISelPseudosID)) + printAndVerify("After ExpandISelPseudos"); // Add passes that optimize machine instructions in SSA form. if (getOptLevel() != CodeGenOpt::None) { addMachineSSAOptimization(); - } - else { + } 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); @@ -471,14 +547,18 @@ void TargetPassConfig::addMachinePasses() { // Second pass scheduler. if (getOptLevel() != CodeGenOpt::None) { - addPass(&PostRASchedulerID); + if (MISchedPostRA) + addPass(&PostMachineSchedulerID); + else + addPass(&PostRASchedulerID); printAndVerify("After PostRAScheduler"); } // GC - addPass(&GCMachineCodeAnalysisID); - if (PrintGCInfo) - addPass(createGCInfoPrinter(dbgs())); + if (addGCPasses()) { + if (PrintGCInfo) + addPass(createGCInfoPrinter(dbgs())); + } // Basic block placement. if (getOptLevel() != CodeGenOpt::None) @@ -486,6 +566,8 @@ void TargetPassConfig::addMachinePasses() { if (addPreEmitPass()) printAndVerify("After PreEmit passes"); + + addPass(&StackMapLivenessID); } /// Add passes that optimize machine instructions in SSA form. @@ -498,6 +580,10 @@ void TargetPassConfig::addMachineSSAOptimization() { // instructions dead. addPass(&OptimizePHIsID); + // This pass merges large allocas. StackSlotColoring is a different pass + // which merges spill slots. + addPass(&StackColoringID); + // If the target requests it, assign local variables to stack slots relative // to one another and simplify frame index references where possible. addPass(&LocalStackSlotAllocationID); @@ -509,12 +595,21 @@ void TargetPassConfig::addMachineSSAOptimization() { addPass(&DeadMachineInstructionElimID); printAndVerify("After codegen DCE pass"); + // Allow targets to insert passes that improve instruction level parallelism, + // like if-conversion. Such passes will typically need dominator trees and + // loop info, just like LICM and CSE below. + if (addILPOpts()) + printAndVerify("After ILP optimizations"); + addPass(&MachineLICMID); addPass(&MachineCSEID); addPass(&MachineSinkingID); printAndVerify("After Machine LICM, CSE and Sinking passes"); addPass(&PeepholeOptimizerID); + // Clean-up the dead code that may have been generated by peephole + // rewriting. + addPass(&DeadMachineInstructionElimID); printAndVerify("After codegen peephole optimization pass"); } @@ -536,7 +631,7 @@ 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 FunctionPass *useDefaultRegisterAllocator() { return nullptr; } static RegisterRegAlloc defaultRegAlloc("default", "pick register allocator based on -O option", @@ -613,19 +708,15 @@ void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) { // 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); + // Edge splitting is smarter with machine loop info. + addPass(&MachineLoopInfoID); + addPass(&PHIEliminationID); - if (EnableStrongPHIElim) - addPass(&StrongPHIEliminationID); + // Eventually, we want to run LiveIntervals before PHI elimination. + if (EarlyLiveIntervals) + addPass(&LiveIntervalsID); + addPass(&TwoAddressInstructionPassID); addPass(&RegisterCoalescerID); // PreRA instruction scheduling. @@ -644,14 +735,6 @@ void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) { addPass(&VirtRegRewriterID); printAndVerify("After Virtual Register Rewriter"); - // 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 @@ -677,7 +760,10 @@ void TargetPassConfig::addMachineLateOptimization() { printAndVerify("After BranchFolding"); // Tail duplication. - if (addPass(&TailDuplicateID)) + // Note that duplicating tail just increases code size and degrades + // performance for targets that require Structured Control Flow. + // In addition it can also make CFG irreducible. Thus we disable it. + if (!TM->requiresStructuredCFG() && addPass(&TailDuplicateID)) printAndVerify("After TailDuplicate"); // Copy propagation. @@ -685,18 +771,15 @@ void TargetPassConfig::addMachineLateOptimization() { printAndVerify("After copy propagation pass"); } +/// Add standard GC passes. +bool TargetPassConfig::addGCPasses() { + addPass(&GCMachineCodeAnalysisID); + return true; +} + /// Add standard basic block placement passes. void TargetPassConfig::addBlockPlacement() { - AnalysisID PassID = 0; - if (!DisableBlockPlacement) { - // MachineBlockPlacement is a new pass which subsumes the functionality of - // CodPlacementOpt. The old code placement pass can be restored by - // disabling block placement, but eventually it will be removed. - PassID = addPass(&MachineBlockPlacementID); - } else { - PassID = addPass(&CodePlacementOptID); - } - if (PassID) { + if (addPass(&MachineBlockPlacementID)) { // Run a separate pass to collect block placement statistics. if (EnableBlockPlacementStats) addPass(&MachineBlockPlacementStatsID);