| //===- EarlyCSE.cpp - Simple and fast CSE 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 pass performs a simple dominator tree walk that eliminates trivially |
| // redundant instructions. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/Scalar/EarlyCSE.h" |
| #include "llvm/ADT/DenseMapInfo.h" |
| #include "llvm/ADT/Hashing.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/ScopedHashTable.h" |
| #include "llvm/ADT/SetVector.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/Analysis/AssumptionCache.h" |
| #include "llvm/Analysis/GlobalsModRef.h" |
| #include "llvm/Analysis/GuardUtils.h" |
| #include "llvm/Analysis/InstructionSimplify.h" |
| #include "llvm/Analysis/MemorySSA.h" |
| #include "llvm/Analysis/MemorySSAUpdater.h" |
| #include "llvm/Analysis/TargetLibraryInfo.h" |
| #include "llvm/Analysis/TargetTransformInfo.h" |
| #include "llvm/Analysis/ValueTracking.h" |
| #include "llvm/IR/BasicBlock.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/Dominators.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/InstrTypes.h" |
| #include "llvm/IR/Instruction.h" |
| #include "llvm/IR/Instructions.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/Intrinsics.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/IR/PassManager.h" |
| #include "llvm/IR/PatternMatch.h" |
| #include "llvm/IR/Type.h" |
| #include "llvm/IR/Use.h" |
| #include "llvm/IR/Value.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/Allocator.h" |
| #include "llvm/Support/AtomicOrdering.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/DebugCounter.h" |
| #include "llvm/Support/RecyclingAllocator.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Transforms/Scalar.h" |
| #include "llvm/Transforms/Utils/AssumeBundleBuilder.h" |
| #include "llvm/Transforms/Utils/GuardUtils.h" |
| #include "llvm/Transforms/Utils/Local.h" |
| #include <cassert> |
| #include <deque> |
| #include <memory> |
| #include <utility> |
| |
| using namespace llvm; |
| using namespace llvm::PatternMatch; |
| |
| #define DEBUG_TYPE "early-cse" |
| |
| STATISTIC(NumSimplify, "Number of instructions simplified or DCE'd"); |
| STATISTIC(NumCSE, "Number of instructions CSE'd"); |
| STATISTIC(NumCSECVP, "Number of compare instructions CVP'd"); |
| STATISTIC(NumCSELoad, "Number of load instructions CSE'd"); |
| STATISTIC(NumCSECall, "Number of call instructions CSE'd"); |
| STATISTIC(NumDSE, "Number of trivial dead stores removed"); |
| |
| DEBUG_COUNTER(CSECounter, "early-cse", |
| "Controls which instructions are removed"); |
| |
| static cl::opt<unsigned> EarlyCSEMssaOptCap( |
| "earlycse-mssa-optimization-cap", cl::init(500), cl::Hidden, |
| cl::desc("Enable imprecision in EarlyCSE in pathological cases, in exchange " |
| "for faster compile. Caps the MemorySSA clobbering calls.")); |
| |
| static cl::opt<bool> EarlyCSEDebugHash( |
| "earlycse-debug-hash", cl::init(false), cl::Hidden, |
| cl::desc("Perform extra assertion checking to verify that SimpleValue's hash " |
| "function is well-behaved w.r.t. its isEqual predicate")); |
| |
| //===----------------------------------------------------------------------===// |
| // SimpleValue |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| |
| /// Struct representing the available values in the scoped hash table. |
| struct SimpleValue { |
| Instruction *Inst; |
| |
| SimpleValue(Instruction *I) : Inst(I) { |
| assert((isSentinel() || canHandle(I)) && "Inst can't be handled!"); |
| } |
| |
| bool isSentinel() const { |
| return Inst == DenseMapInfo<Instruction *>::getEmptyKey() || |
| Inst == DenseMapInfo<Instruction *>::getTombstoneKey(); |
| } |
| |
| static bool canHandle(Instruction *Inst) { |
| // This can only handle non-void readnone functions. |
| // Also handled are constrained intrinsic that look like the types |
| // of instruction handled below (UnaryOperator, etc.). |
| if (CallInst *CI = dyn_cast<CallInst>(Inst)) { |
| if (Function *F = CI->getCalledFunction()) { |
| switch ((Intrinsic::ID)F->getIntrinsicID()) { |
| case Intrinsic::experimental_constrained_fadd: |
| case Intrinsic::experimental_constrained_fsub: |
| case Intrinsic::experimental_constrained_fmul: |
| case Intrinsic::experimental_constrained_fdiv: |
| case Intrinsic::experimental_constrained_frem: |
| case Intrinsic::experimental_constrained_fptosi: |
| case Intrinsic::experimental_constrained_sitofp: |
| case Intrinsic::experimental_constrained_fptoui: |
| case Intrinsic::experimental_constrained_uitofp: |
| case Intrinsic::experimental_constrained_fcmp: |
| case Intrinsic::experimental_constrained_fcmps: { |
| auto *CFP = cast<ConstrainedFPIntrinsic>(CI); |
| return CFP->isDefaultFPEnvironment(); |
| } |
| } |
| } |
| return CI->doesNotAccessMemory() && !CI->getType()->isVoidTy(); |
| } |
| return isa<CastInst>(Inst) || isa<UnaryOperator>(Inst) || |
| isa<BinaryOperator>(Inst) || isa<GetElementPtrInst>(Inst) || |
| isa<CmpInst>(Inst) || isa<SelectInst>(Inst) || |
| isa<ExtractElementInst>(Inst) || isa<InsertElementInst>(Inst) || |
| isa<ShuffleVectorInst>(Inst) || isa<ExtractValueInst>(Inst) || |
| isa<InsertValueInst>(Inst) || isa<FreezeInst>(Inst); |
| } |
| }; |
| |
| } // end anonymous namespace |
| |
| namespace llvm { |
| |
| template <> struct DenseMapInfo<SimpleValue> { |
| static inline SimpleValue getEmptyKey() { |
| return DenseMapInfo<Instruction *>::getEmptyKey(); |
| } |
| |
| static inline SimpleValue getTombstoneKey() { |
| return DenseMapInfo<Instruction *>::getTombstoneKey(); |
| } |
| |
| static unsigned getHashValue(SimpleValue Val); |
| static bool isEqual(SimpleValue LHS, SimpleValue RHS); |
| }; |
| |
| } // end namespace llvm |
| |
| /// Match a 'select' including an optional 'not's of the condition. |
| static bool matchSelectWithOptionalNotCond(Value *V, Value *&Cond, Value *&A, |
| Value *&B, |
| SelectPatternFlavor &Flavor) { |
| // Return false if V is not even a select. |
| if (!match(V, m_Select(m_Value(Cond), m_Value(A), m_Value(B)))) |
| return false; |
| |
| // Look through a 'not' of the condition operand by swapping A/B. |
| Value *CondNot; |
| if (match(Cond, m_Not(m_Value(CondNot)))) { |
| Cond = CondNot; |
| std::swap(A, B); |
| } |
| |
| // Match canonical forms of min/max. We are not using ValueTracking's |
| // more powerful matchSelectPattern() because it may rely on instruction flags |
| // such as "nsw". That would be incompatible with the current hashing |
| // mechanism that may remove flags to increase the likelihood of CSE. |
| |
| Flavor = SPF_UNKNOWN; |
| CmpInst::Predicate Pred; |
| |
| if (!match(Cond, m_ICmp(Pred, m_Specific(A), m_Specific(B)))) { |
| // Check for commuted variants of min/max by swapping predicate. |
| // If we do not match the standard or commuted patterns, this is not a |
| // recognized form of min/max, but it is still a select, so return true. |
| if (!match(Cond, m_ICmp(Pred, m_Specific(B), m_Specific(A)))) |
| return true; |
| Pred = ICmpInst::getSwappedPredicate(Pred); |
| } |
| |
| switch (Pred) { |
| case CmpInst::ICMP_UGT: Flavor = SPF_UMAX; break; |
| case CmpInst::ICMP_ULT: Flavor = SPF_UMIN; break; |
| case CmpInst::ICMP_SGT: Flavor = SPF_SMAX; break; |
| case CmpInst::ICMP_SLT: Flavor = SPF_SMIN; break; |
| // Non-strict inequalities. |
| case CmpInst::ICMP_ULE: Flavor = SPF_UMIN; break; |
| case CmpInst::ICMP_UGE: Flavor = SPF_UMAX; break; |
| case CmpInst::ICMP_SLE: Flavor = SPF_SMIN; break; |
| case CmpInst::ICMP_SGE: Flavor = SPF_SMAX; break; |
| default: break; |
| } |
| |
| return true; |
| } |
| |
| static unsigned getHashValueImpl(SimpleValue Val) { |
| Instruction *Inst = Val.Inst; |
| // Hash in all of the operands as pointers. |
| if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst)) { |
| Value *LHS = BinOp->getOperand(0); |
| Value *RHS = BinOp->getOperand(1); |
| if (BinOp->isCommutative() && BinOp->getOperand(0) > BinOp->getOperand(1)) |
| std::swap(LHS, RHS); |
| |
| return hash_combine(BinOp->getOpcode(), LHS, RHS); |
| } |
| |
| if (CmpInst *CI = dyn_cast<CmpInst>(Inst)) { |
| // Compares can be commuted by swapping the comparands and |
| // updating the predicate. Choose the form that has the |
| // comparands in sorted order, or in the case of a tie, the |
| // one with the lower predicate. |
| Value *LHS = CI->getOperand(0); |
| Value *RHS = CI->getOperand(1); |
| CmpInst::Predicate Pred = CI->getPredicate(); |
| CmpInst::Predicate SwappedPred = CI->getSwappedPredicate(); |
| if (std::tie(LHS, Pred) > std::tie(RHS, SwappedPred)) { |
| std::swap(LHS, RHS); |
| Pred = SwappedPred; |
| } |
| return hash_combine(Inst->getOpcode(), Pred, LHS, RHS); |
| } |
| |
| // Hash general selects to allow matching commuted true/false operands. |
| SelectPatternFlavor SPF; |
| Value *Cond, *A, *B; |
| if (matchSelectWithOptionalNotCond(Inst, Cond, A, B, SPF)) { |
| // Hash min/max (cmp + select) to allow for commuted operands. |
| // Min/max may also have non-canonical compare predicate (eg, the compare for |
| // smin may use 'sgt' rather than 'slt'), and non-canonical operands in the |
| // compare. |
| // TODO: We should also detect FP min/max. |
| if (SPF == SPF_SMIN || SPF == SPF_SMAX || |
| SPF == SPF_UMIN || SPF == SPF_UMAX) { |
| if (A > B) |
| std::swap(A, B); |
| return hash_combine(Inst->getOpcode(), SPF, A, B); |
| } |
| |
| // Hash general selects to allow matching commuted true/false operands. |
| |
| // If we do not have a compare as the condition, just hash in the condition. |
| CmpInst::Predicate Pred; |
| Value *X, *Y; |
| if (!match(Cond, m_Cmp(Pred, m_Value(X), m_Value(Y)))) |
| return hash_combine(Inst->getOpcode(), Cond, A, B); |
| |
| // Similar to cmp normalization (above) - canonicalize the predicate value: |
| // select (icmp Pred, X, Y), A, B --> select (icmp InvPred, X, Y), B, A |
| if (CmpInst::getInversePredicate(Pred) < Pred) { |
| Pred = CmpInst::getInversePredicate(Pred); |
| std::swap(A, B); |
| } |
| return hash_combine(Inst->getOpcode(), Pred, X, Y, A, B); |
| } |
| |
| if (CastInst *CI = dyn_cast<CastInst>(Inst)) |
| return hash_combine(CI->getOpcode(), CI->getType(), CI->getOperand(0)); |
| |
| if (FreezeInst *FI = dyn_cast<FreezeInst>(Inst)) |
| return hash_combine(FI->getOpcode(), FI->getOperand(0)); |
| |
| if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(Inst)) |
| return hash_combine(EVI->getOpcode(), EVI->getOperand(0), |
| hash_combine_range(EVI->idx_begin(), EVI->idx_end())); |
| |
| if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(Inst)) |
| return hash_combine(IVI->getOpcode(), IVI->getOperand(0), |
| IVI->getOperand(1), |
| hash_combine_range(IVI->idx_begin(), IVI->idx_end())); |
| |
| assert((isa<CallInst>(Inst) || isa<GetElementPtrInst>(Inst) || |
| isa<ExtractElementInst>(Inst) || isa<InsertElementInst>(Inst) || |
| isa<ShuffleVectorInst>(Inst) || isa<UnaryOperator>(Inst) || |
| isa<FreezeInst>(Inst)) && |
| "Invalid/unknown instruction"); |
| |
| // Handle intrinsics with commutative operands. |
| // TODO: Extend this to handle intrinsics with >2 operands where the 1st |
| // 2 operands are commutative. |
| auto *II = dyn_cast<IntrinsicInst>(Inst); |
| if (II && II->isCommutative() && II->arg_size() == 2) { |
| Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); |
| if (LHS > RHS) |
| std::swap(LHS, RHS); |
| return hash_combine(II->getOpcode(), LHS, RHS); |
| } |
| |
| // gc.relocate is 'special' call: its second and third operands are |
| // not real values, but indices into statepoint's argument list. |
| // Get values they point to. |
| if (const GCRelocateInst *GCR = dyn_cast<GCRelocateInst>(Inst)) |
| return hash_combine(GCR->getOpcode(), GCR->getOperand(0), |
| GCR->getBasePtr(), GCR->getDerivedPtr()); |
| |
| // Mix in the opcode. |
| return hash_combine( |
| Inst->getOpcode(), |
| hash_combine_range(Inst->value_op_begin(), Inst->value_op_end())); |
| } |
| |
| unsigned DenseMapInfo<SimpleValue>::getHashValue(SimpleValue Val) { |
| #ifndef NDEBUG |
| // If -earlycse-debug-hash was specified, return a constant -- this |
| // will force all hashing to collide, so we'll exhaustively search |
| // the table for a match, and the assertion in isEqual will fire if |
| // there's a bug causing equal keys to hash differently. |
| if (EarlyCSEDebugHash) |
| return 0; |
| #endif |
| return getHashValueImpl(Val); |
| } |
| |
| static bool isEqualImpl(SimpleValue LHS, SimpleValue RHS) { |
| Instruction *LHSI = LHS.Inst, *RHSI = RHS.Inst; |
| |
| if (LHS.isSentinel() || RHS.isSentinel()) |
| return LHSI == RHSI; |
| |
| if (LHSI->getOpcode() != RHSI->getOpcode()) |
| return false; |
| if (LHSI->isIdenticalToWhenDefined(RHSI)) |
| return true; |
| |
| // If we're not strictly identical, we still might be a commutable instruction |
| if (BinaryOperator *LHSBinOp = dyn_cast<BinaryOperator>(LHSI)) { |
| if (!LHSBinOp->isCommutative()) |
| return false; |
| |
| assert(isa<BinaryOperator>(RHSI) && |
| "same opcode, but different instruction type?"); |
| BinaryOperator *RHSBinOp = cast<BinaryOperator>(RHSI); |
| |
| // Commuted equality |
| return LHSBinOp->getOperand(0) == RHSBinOp->getOperand(1) && |
| LHSBinOp->getOperand(1) == RHSBinOp->getOperand(0); |
| } |
| if (CmpInst *LHSCmp = dyn_cast<CmpInst>(LHSI)) { |
| assert(isa<CmpInst>(RHSI) && |
| "same opcode, but different instruction type?"); |
| CmpInst *RHSCmp = cast<CmpInst>(RHSI); |
| // Commuted equality |
| return LHSCmp->getOperand(0) == RHSCmp->getOperand(1) && |
| LHSCmp->getOperand(1) == RHSCmp->getOperand(0) && |
| LHSCmp->getSwappedPredicate() == RHSCmp->getPredicate(); |
| } |
| |
| // TODO: Extend this for >2 args by matching the trailing N-2 args. |
| auto *LII = dyn_cast<IntrinsicInst>(LHSI); |
| auto *RII = dyn_cast<IntrinsicInst>(RHSI); |
| if (LII && RII && LII->getIntrinsicID() == RII->getIntrinsicID() && |
| LII->isCommutative() && LII->arg_size() == 2) { |
| return LII->getArgOperand(0) == RII->getArgOperand(1) && |
| LII->getArgOperand(1) == RII->getArgOperand(0); |
| } |
| |
| // See comment above in `getHashValue()`. |
| if (const GCRelocateInst *GCR1 = dyn_cast<GCRelocateInst>(LHSI)) |
| if (const GCRelocateInst *GCR2 = dyn_cast<GCRelocateInst>(RHSI)) |
| return GCR1->getOperand(0) == GCR2->getOperand(0) && |
| GCR1->getBasePtr() == GCR2->getBasePtr() && |
| GCR1->getDerivedPtr() == GCR2->getDerivedPtr(); |
| |
| // Min/max can occur with commuted operands, non-canonical predicates, |
| // and/or non-canonical operands. |
| // Selects can be non-trivially equivalent via inverted conditions and swaps. |
| SelectPatternFlavor LSPF, RSPF; |
| Value *CondL, *CondR, *LHSA, *RHSA, *LHSB, *RHSB; |
| if (matchSelectWithOptionalNotCond(LHSI, CondL, LHSA, LHSB, LSPF) && |
| matchSelectWithOptionalNotCond(RHSI, CondR, RHSA, RHSB, RSPF)) { |
| if (LSPF == RSPF) { |
| // TODO: We should also detect FP min/max. |
| if (LSPF == SPF_SMIN || LSPF == SPF_SMAX || |
| LSPF == SPF_UMIN || LSPF == SPF_UMAX) |
| return ((LHSA == RHSA && LHSB == RHSB) || |
| (LHSA == RHSB && LHSB == RHSA)); |
| |
| // select Cond, A, B <--> select not(Cond), B, A |
| if (CondL == CondR && LHSA == RHSA && LHSB == RHSB) |
| return true; |
| } |
| |
| // If the true/false operands are swapped and the conditions are compares |
| // with inverted predicates, the selects are equal: |
| // select (icmp Pred, X, Y), A, B <--> select (icmp InvPred, X, Y), B, A |
| // |
| // This also handles patterns with a double-negation in the sense of not + |
| // inverse, because we looked through a 'not' in the matching function and |
| // swapped A/B: |
| // select (cmp Pred, X, Y), A, B <--> select (not (cmp InvPred, X, Y)), B, A |
| // |
| // This intentionally does NOT handle patterns with a double-negation in |
| // the sense of not + not, because doing so could result in values |
| // comparing |
| // as equal that hash differently in the min/max cases like: |
| // select (cmp slt, X, Y), X, Y <--> select (not (not (cmp slt, X, Y))), X, Y |
| // ^ hashes as min ^ would not hash as min |
| // In the context of the EarlyCSE pass, however, such cases never reach |
| // this code, as we simplify the double-negation before hashing the second |
| // select (and so still succeed at CSEing them). |
| if (LHSA == RHSB && LHSB == RHSA) { |
| CmpInst::Predicate PredL, PredR; |
| Value *X, *Y; |
| if (match(CondL, m_Cmp(PredL, m_Value(X), m_Value(Y))) && |
| match(CondR, m_Cmp(PredR, m_Specific(X), m_Specific(Y))) && |
| CmpInst::getInversePredicate(PredL) == PredR) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| bool DenseMapInfo<SimpleValue>::isEqual(SimpleValue LHS, SimpleValue RHS) { |
| // These comparisons are nontrivial, so assert that equality implies |
| // hash equality (DenseMap demands this as an invariant). |
| bool Result = isEqualImpl(LHS, RHS); |
| assert(!Result || (LHS.isSentinel() && LHS.Inst == RHS.Inst) || |
| getHashValueImpl(LHS) == getHashValueImpl(RHS)); |
| return Result; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // CallValue |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| |
| /// Struct representing the available call values in the scoped hash |
| /// table. |
| struct CallValue { |
| Instruction *Inst; |
| |
| CallValue(Instruction *I) : Inst(I) { |
| assert((isSentinel() || canHandle(I)) && "Inst can't be handled!"); |
| } |
| |
| bool isSentinel() const { |
| return Inst == DenseMapInfo<Instruction *>::getEmptyKey() || |
| Inst == DenseMapInfo<Instruction *>::getTombstoneKey(); |
| } |
| |
| static bool canHandle(Instruction *Inst) { |
| // Don't value number anything that returns void. |
| if (Inst->getType()->isVoidTy()) |
| return false; |
| |
| CallInst *CI = dyn_cast<CallInst>(Inst); |
| if (!CI || !CI->onlyReadsMemory()) |
| return false; |
| return true; |
| } |
| }; |
| |
| } // end anonymous namespace |
| |
| namespace llvm { |
| |
| template <> struct DenseMapInfo<CallValue> { |
| static inline CallValue getEmptyKey() { |
| return DenseMapInfo<Instruction *>::getEmptyKey(); |
| } |
| |
| static inline CallValue getTombstoneKey() { |
| return DenseMapInfo<Instruction *>::getTombstoneKey(); |
| } |
| |
| static unsigned getHashValue(CallValue Val); |
| static bool isEqual(CallValue LHS, CallValue RHS); |
| }; |
| |
| } // end namespace llvm |
| |
| unsigned DenseMapInfo<CallValue>::getHashValue(CallValue Val) { |
| Instruction *Inst = Val.Inst; |
| |
| // Hash all of the operands as pointers and mix in the opcode. |
| return hash_combine( |
| Inst->getOpcode(), |
| hash_combine_range(Inst->value_op_begin(), Inst->value_op_end())); |
| } |
| |
| bool DenseMapInfo<CallValue>::isEqual(CallValue LHS, CallValue RHS) { |
| Instruction *LHSI = LHS.Inst, *RHSI = RHS.Inst; |
| if (LHS.isSentinel() || RHS.isSentinel()) |
| return LHSI == RHSI; |
| |
| return LHSI->isIdenticalTo(RHSI); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // EarlyCSE implementation |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| |
| /// A simple and fast domtree-based CSE pass. |
| /// |
| /// This pass does a simple depth-first walk over the dominator tree, |
| /// eliminating trivially redundant instructions and using instsimplify to |
| /// canonicalize things as it goes. It is intended to be fast and catch obvious |
| /// cases so that instcombine and other passes are more effective. It is |
| /// expected that a later pass of GVN will catch the interesting/hard cases. |
| class EarlyCSE { |
| public: |
| const TargetLibraryInfo &TLI; |
| const TargetTransformInfo &TTI; |
| DominatorTree &DT; |
| AssumptionCache &AC; |
| const SimplifyQuery SQ; |
| MemorySSA *MSSA; |
| std::unique_ptr<MemorySSAUpdater> MSSAUpdater; |
| |
| using AllocatorTy = |
| RecyclingAllocator<BumpPtrAllocator, |
| ScopedHashTableVal<SimpleValue, Value *>>; |
| using ScopedHTType = |
| ScopedHashTable<SimpleValue, Value *, DenseMapInfo<SimpleValue>, |
| AllocatorTy>; |
| |
| /// A scoped hash table of the current values of all of our simple |
| /// scalar expressions. |
| /// |
| /// As we walk down the domtree, we look to see if instructions are in this: |
| /// if so, we replace them with what we find, otherwise we insert them so |
| /// that dominated values can succeed in their lookup. |
| ScopedHTType AvailableValues; |
| |
| /// A scoped hash table of the current values of previously encountered |
| /// memory locations. |
| /// |
| /// This allows us to get efficient access to dominating loads or stores when |
| /// we have a fully redundant load. In addition to the most recent load, we |
| /// keep track of a generation count of the read, which is compared against |
| /// the current generation count. The current generation count is incremented |
| /// after every possibly writing memory operation, which ensures that we only |
| /// CSE loads with other loads that have no intervening store. Ordering |
| /// events (such as fences or atomic instructions) increment the generation |
| /// count as well; essentially, we model these as writes to all possible |
| /// locations. Note that atomic and/or volatile loads and stores can be |
| /// present the table; it is the responsibility of the consumer to inspect |
| /// the atomicity/volatility if needed. |
| struct LoadValue { |
| Instruction *DefInst = nullptr; |
| unsigned Generation = 0; |
| int MatchingId = -1; |
| bool IsAtomic = false; |
| |
| LoadValue() = default; |
| LoadValue(Instruction *Inst, unsigned Generation, unsigned MatchingId, |
| bool IsAtomic) |
| : DefInst(Inst), Generation(Generation), MatchingId(MatchingId), |
| IsAtomic(IsAtomic) {} |
| }; |
| |
| using LoadMapAllocator = |
| RecyclingAllocator<BumpPtrAllocator, |
| ScopedHashTableVal<Value *, LoadValue>>; |
| using LoadHTType = |
| ScopedHashTable<Value *, LoadValue, DenseMapInfo<Value *>, |
| LoadMapAllocator>; |
| |
| LoadHTType AvailableLoads; |
| |
| // A scoped hash table mapping memory locations (represented as typed |
| // addresses) to generation numbers at which that memory location became |
| // (henceforth indefinitely) invariant. |
| using InvariantMapAllocator = |
| RecyclingAllocator<BumpPtrAllocator, |
| ScopedHashTableVal<MemoryLocation, unsigned>>; |
| using InvariantHTType = |
| ScopedHashTable<MemoryLocation, unsigned, DenseMapInfo<MemoryLocation>, |
| InvariantMapAllocator>; |
| InvariantHTType AvailableInvariants; |
| |
| /// A scoped hash table of the current values of read-only call |
| /// values. |
| /// |
| /// It uses the same generation count as loads. |
| using CallHTType = |
| ScopedHashTable<CallValue, std::pair<Instruction *, unsigned>>; |
| CallHTType AvailableCalls; |
| |
| /// This is the current generation of the memory value. |
| unsigned CurrentGeneration = 0; |
| |
| /// Set up the EarlyCSE runner for a particular function. |
| EarlyCSE(const DataLayout &DL, const TargetLibraryInfo &TLI, |
| const TargetTransformInfo &TTI, DominatorTree &DT, |
| AssumptionCache &AC, MemorySSA *MSSA) |
| : TLI(TLI), TTI(TTI), DT(DT), AC(AC), SQ(DL, &TLI, &DT, &AC), MSSA(MSSA), |
| MSSAUpdater(std::make_unique<MemorySSAUpdater>(MSSA)) {} |
| |
| bool run(); |
| |
| private: |
| unsigned ClobberCounter = 0; |
| // Almost a POD, but needs to call the constructors for the scoped hash |
| // tables so that a new scope gets pushed on. These are RAII so that the |
| // scope gets popped when the NodeScope is destroyed. |
| class NodeScope { |
| public: |
| NodeScope(ScopedHTType &AvailableValues, LoadHTType &AvailableLoads, |
| InvariantHTType &AvailableInvariants, CallHTType &AvailableCalls) |
| : Scope(AvailableValues), LoadScope(AvailableLoads), |
| InvariantScope(AvailableInvariants), CallScope(AvailableCalls) {} |
| NodeScope(const NodeScope &) = delete; |
| NodeScope &operator=(const NodeScope &) = delete; |
| |
| private: |
| ScopedHTType::ScopeTy Scope; |
| LoadHTType::ScopeTy LoadScope; |
| InvariantHTType::ScopeTy InvariantScope; |
| CallHTType::ScopeTy CallScope; |
| }; |
| |
| // Contains all the needed information to create a stack for doing a depth |
| // first traversal of the tree. This includes scopes for values, loads, and |
| // calls as well as the generation. There is a child iterator so that the |
| // children do not need to be store separately. |
| class StackNode { |
| public: |
| StackNode(ScopedHTType &AvailableValues, LoadHTType &AvailableLoads, |
| InvariantHTType &AvailableInvariants, CallHTType &AvailableCalls, |
| unsigned cg, DomTreeNode *n, DomTreeNode::const_iterator child, |
| DomTreeNode::const_iterator end) |
| : CurrentGeneration(cg), ChildGeneration(cg), Node(n), ChildIter(child), |
| EndIter(end), |
| Scopes(AvailableValues, AvailableLoads, AvailableInvariants, |
| AvailableCalls) |
| {} |
| StackNode(const StackNode &) = delete; |
| StackNode &operator=(const StackNode &) = delete; |
| |
| // Accessors. |
| unsigned currentGeneration() const { return CurrentGeneration; } |
| unsigned childGeneration() const { return ChildGeneration; } |
| void childGeneration(unsigned generation) { ChildGeneration = generation; } |
| DomTreeNode *node() { return Node; } |
| DomTreeNode::const_iterator childIter() const { return ChildIter; } |
| |
| DomTreeNode *nextChild() { |
| DomTreeNode *child = *ChildIter; |
| ++ChildIter; |
| return child; |
| } |
| |
| DomTreeNode::const_iterator end() const { return EndIter; } |
| bool isProcessed() const { return Processed; } |
| void process() { Processed = true; } |
| |
| private: |
| unsigned CurrentGeneration; |
| unsigned ChildGeneration; |
| DomTreeNode *Node; |
| DomTreeNode::const_iterator ChildIter; |
| DomTreeNode::const_iterator EndIter; |
| NodeScope Scopes; |
| bool Processed = false; |
| }; |
| |
| /// Wrapper class to handle memory instructions, including loads, |
| /// stores and intrinsic loads and stores defined by the target. |
| class ParseMemoryInst { |
| public: |
| ParseMemoryInst(Instruction *Inst, const TargetTransformInfo &TTI) |
| : Inst(Inst) { |
| if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) { |
| IntrID = II->getIntrinsicID(); |
| if (TTI.getTgtMemIntrinsic(II, Info)) |
| return; |
| if (isHandledNonTargetIntrinsic(IntrID)) { |
| switch (IntrID) { |
| case Intrinsic::masked_load: |
| Info.PtrVal = Inst->getOperand(0); |
| Info.MatchingId = Intrinsic::masked_load; |
| Info.ReadMem = true; |
| Info.WriteMem = false; |
| Info.IsVolatile = false; |
| break; |
| case Intrinsic::masked_store: |
| Info.PtrVal = Inst->getOperand(1); |
| // Use the ID of masked load as the "matching id". This will |
| // prevent matching non-masked loads/stores with masked ones |
| // (which could be done), but at the moment, the code here |
| // does not support matching intrinsics with non-intrinsics, |
| // so keep the MatchingIds specific to masked instructions |
| // for now (TODO). |
| Info.MatchingId = Intrinsic::masked_load; |
| Info.ReadMem = false; |
| Info.WriteMem = true; |
| Info.IsVolatile = false; |
| break; |
| } |
| } |
| } |
| } |
| |
| Instruction *get() { return Inst; } |
| const Instruction *get() const { return Inst; } |
| |
| bool isLoad() const { |
| if (IntrID != 0) |
| return Info.ReadMem; |
| return isa<LoadInst>(Inst); |
| } |
| |
| bool isStore() const { |
| if (IntrID != 0) |
| return Info.WriteMem; |
| return isa<StoreInst>(Inst); |
| } |
| |
| bool isAtomic() const { |
| if (IntrID != 0) |
| return Info.Ordering != AtomicOrdering::NotAtomic; |
| return Inst->isAtomic(); |
| } |
| |
| bool isUnordered() const { |
| if (IntrID != 0) |
| return Info.isUnordered(); |
| |
| if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) { |
| return LI->isUnordered(); |
| } else if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { |
| return SI->isUnordered(); |
| } |
| // Conservative answer |
| return !Inst->isAtomic(); |
| } |
| |
| bool isVolatile() const { |
| if (IntrID != 0) |
| return Info.IsVolatile; |
| |
| if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) { |
| return LI->isVolatile(); |
| } else if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { |
| return SI->isVolatile(); |
| } |
| // Conservative answer |
| return true; |
| } |
| |
| bool isInvariantLoad() const { |
| if (auto *LI = dyn_cast<LoadInst>(Inst)) |
| return LI->hasMetadata(LLVMContext::MD_invariant_load); |
| return false; |
| } |
| |
| bool isValid() const { return getPointerOperand() != nullptr; } |
| |
| // For regular (non-intrinsic) loads/stores, this is set to -1. For |
| // intrinsic loads/stores, the id is retrieved from the corresponding |
| // field in the MemIntrinsicInfo structure. That field contains |
| // non-negative values only. |
| int getMatchingId() const { |
| if (IntrID != 0) |
| return Info.MatchingId; |
| return -1; |
| } |
| |
| Value *getPointerOperand() const { |
| if (IntrID != 0) |
| return Info.PtrVal; |
| return getLoadStorePointerOperand(Inst); |
| } |
| |
| bool mayReadFromMemory() const { |
| if (IntrID != 0) |
| return Info.ReadMem; |
| return Inst->mayReadFromMemory(); |
| } |
| |
| bool mayWriteToMemory() const { |
| if (IntrID != 0) |
| return Info.WriteMem; |
| return Inst->mayWriteToMemory(); |
| } |
| |
| private: |
| Intrinsic::ID IntrID = 0; |
| MemIntrinsicInfo Info; |
| Instruction *Inst; |
| }; |
| |
| // This function is to prevent accidentally passing a non-target |
| // intrinsic ID to TargetTransformInfo. |
| static bool isHandledNonTargetIntrinsic(Intrinsic::ID ID) { |
| switch (ID) { |
| case Intrinsic::masked_load: |
| case Intrinsic::masked_store: |
| return true; |
| } |
| return false; |
| } |
| static bool isHandledNonTargetIntrinsic(const Value *V) { |
| if (auto *II = dyn_cast<IntrinsicInst>(V)) |
| return isHandledNonTargetIntrinsic(II->getIntrinsicID()); |
| return false; |
| } |
| |
| bool processNode(DomTreeNode *Node); |
| |
| bool handleBranchCondition(Instruction *CondInst, const BranchInst *BI, |
| const BasicBlock *BB, const BasicBlock *Pred); |
| |
| Value *getMatchingValue(LoadValue &InVal, ParseMemoryInst &MemInst, |
| unsigned CurrentGeneration); |
| |
| bool overridingStores(const ParseMemoryInst &Earlier, |
| const ParseMemoryInst &Later); |
| |
| Value *getOrCreateResult(Value *Inst, Type *ExpectedType) const { |
| if (auto *LI = dyn_cast<LoadInst>(Inst)) |
| return LI; |
| if (auto *SI = dyn_cast<StoreInst>(Inst)) |
| return SI->getValueOperand(); |
| assert(isa<IntrinsicInst>(Inst) && "Instruction not supported"); |
| auto *II = cast<IntrinsicInst>(Inst); |
| if (isHandledNonTargetIntrinsic(II->getIntrinsicID())) |
| return getOrCreateResultNonTargetMemIntrinsic(II, ExpectedType); |
| return TTI.getOrCreateResultFromMemIntrinsic(II, ExpectedType); |
| } |
| |
| Value *getOrCreateResultNonTargetMemIntrinsic(IntrinsicInst *II, |
| Type *ExpectedType) const { |
| switch (II->getIntrinsicID()) { |
| case Intrinsic::masked_load: |
| return II; |
| case Intrinsic::masked_store: |
| return II->getOperand(0); |
| } |
| return nullptr; |
| } |
| |
| /// Return true if the instruction is known to only operate on memory |
| /// provably invariant in the given "generation". |
| bool isOperatingOnInvariantMemAt(Instruction *I, unsigned GenAt); |
| |
| bool isSameMemGeneration(unsigned EarlierGeneration, unsigned LaterGeneration, |
| Instruction *EarlierInst, Instruction *LaterInst); |
| |
| bool isNonTargetIntrinsicMatch(const IntrinsicInst *Earlier, |
| const IntrinsicInst *Later) { |
| auto IsSubmask = [](const Value *Mask0, const Value *Mask1) { |
| // Is Mask0 a submask of Mask1? |
| if (Mask0 == Mask1) |
| return true; |
| if (isa<UndefValue>(Mask0) || isa<UndefValue>(Mask1)) |
| return false; |
| auto *Vec0 = dyn_cast<ConstantVector>(Mask0); |
| auto *Vec1 = dyn_cast<ConstantVector>(Mask1); |
| if (!Vec0 || !Vec1) |
| return false; |
| assert(Vec0->getType() == Vec1->getType() && |
| "Masks should have the same type"); |
| for (int i = 0, e = Vec0->getNumOperands(); i != e; ++i) { |
| Constant *Elem0 = Vec0->getOperand(i); |
| Constant *Elem1 = Vec1->getOperand(i); |
| auto *Int0 = dyn_cast<ConstantInt>(Elem0); |
| if (Int0 && Int0->isZero()) |
| continue; |
| auto *Int1 = dyn_cast<ConstantInt>(Elem1); |
| if (Int1 && !Int1->isZero()) |
| continue; |
| if (isa<UndefValue>(Elem0) || isa<UndefValue>(Elem1)) |
| return false; |
| if (Elem0 == Elem1) |
| continue; |
| return false; |
| } |
| return true; |
| }; |
| auto PtrOp = [](const IntrinsicInst *II) { |
| if (II->getIntrinsicID() == Intrinsic::masked_load) |
| return II->getOperand(0); |
| if (II->getIntrinsicID() == Intrinsic::masked_store) |
| return II->getOperand(1); |
| llvm_unreachable("Unexpected IntrinsicInst"); |
| }; |
| auto MaskOp = [](const IntrinsicInst *II) { |
| if (II->getIntrinsicID() == Intrinsic::masked_load) |
| return II->getOperand(2); |
| if (II->getIntrinsicID() == Intrinsic::masked_store) |
| return II->getOperand(3); |
| llvm_unreachable("Unexpected IntrinsicInst"); |
| }; |
| auto ThruOp = [](const IntrinsicInst *II) { |
| if (II->getIntrinsicID() == Intrinsic::masked_load) |
| return II->getOperand(3); |
| llvm_unreachable("Unexpected IntrinsicInst"); |
| }; |
| |
| if (PtrOp(Earlier) != PtrOp(Later)) |
| return false; |
| |
| Intrinsic::ID IDE = Earlier->getIntrinsicID(); |
| Intrinsic::ID IDL = Later->getIntrinsicID(); |
| // We could really use specific intrinsic classes for masked loads |
| // and stores in IntrinsicInst.h. |
| if (IDE == Intrinsic::masked_load && IDL == Intrinsic::masked_load) { |
| // Trying to replace later masked load with the earlier one. |
| // Check that the pointers are the same, and |
| // - masks and pass-throughs are the same, or |
| // - replacee's pass-through is "undef" and replacer's mask is a |
| // super-set of the replacee's mask. |
| if (MaskOp(Earlier) == MaskOp(Later) && ThruOp(Earlier) == ThruOp(Later)) |
| return true; |
| if (!isa<UndefValue>(ThruOp(Later))) |
| return false; |
| return IsSubmask(MaskOp(Later), MaskOp(Earlier)); |
| } |
| if (IDE == Intrinsic::masked_store && IDL == Intrinsic::masked_load) { |
| // Trying to replace a load of a stored value with the store's value. |
| // Check that the pointers are the same, and |
| // - load's mask is a subset of store's mask, and |
| // - load's pass-through is "undef". |
| if (!IsSubmask(MaskOp(Later), MaskOp(Earlier))) |
| return false; |
| return isa<UndefValue>(ThruOp(Later)); |
| } |
| if (IDE == Intrinsic::masked_load && IDL == Intrinsic::masked_store) { |
| // Trying to remove a store of the loaded value. |
| // Check that the pointers are the same, and |
| // - store's mask is a subset of the load's mask. |
| return IsSubmask(MaskOp(Later), MaskOp(Earlier)); |
| } |
| if (IDE == Intrinsic::masked_store && IDL == Intrinsic::masked_store) { |
| // Trying to remove a dead store (earlier). |
| // Check that the pointers are the same, |
| // - the to-be-removed store's mask is a subset of the other store's |
| // mask. |
| return IsSubmask(MaskOp(Earlier), MaskOp(Later)); |
| } |
| return false; |
| } |
| |
| void removeMSSA(Instruction &Inst) { |
| if (!MSSA) |
| return; |
| if (VerifyMemorySSA) |
| MSSA->verifyMemorySSA(); |
| // Removing a store here can leave MemorySSA in an unoptimized state by |
| // creating MemoryPhis that have identical arguments and by creating |
| // MemoryUses whose defining access is not an actual clobber. The phi case |
| // is handled by MemorySSA when passing OptimizePhis = true to |
| // removeMemoryAccess. The non-optimized MemoryUse case is lazily updated |
| // by MemorySSA's getClobberingMemoryAccess. |
| MSSAUpdater->removeMemoryAccess(&Inst, true); |
| } |
| }; |
| |
| } // end anonymous namespace |
| |
| /// Determine if the memory referenced by LaterInst is from the same heap |
| /// version as EarlierInst. |
| /// This is currently called in two scenarios: |
| /// |
| /// load p |
| /// ... |
| /// load p |
| /// |
| /// and |
| /// |
| /// x = load p |
| /// ... |
| /// store x, p |
| /// |
| /// in both cases we want to verify that there are no possible writes to the |
| /// memory referenced by p between the earlier and later instruction. |
| bool EarlyCSE::isSameMemGeneration(unsigned EarlierGeneration, |
| unsigned LaterGeneration, |
| Instruction *EarlierInst, |
| Instruction *LaterInst) { |
| // Check the simple memory generation tracking first. |
| if (EarlierGeneration == LaterGeneration) |
| return true; |
| |
| if (!MSSA) |
| return false; |
| |
| // If MemorySSA has determined that one of EarlierInst or LaterInst does not |
| // read/write memory, then we can safely return true here. |
| // FIXME: We could be more aggressive when checking doesNotAccessMemory(), |
| // onlyReadsMemory(), mayReadFromMemory(), and mayWriteToMemory() in this pass |
| // by also checking the MemorySSA MemoryAccess on the instruction. Initial |
| // experiments suggest this isn't worthwhile, at least for C/C++ code compiled |
| // with the default optimization pipeline. |
| auto *EarlierMA = MSSA->getMemoryAccess(EarlierInst); |
| if (!EarlierMA) |
| return true; |
| auto *LaterMA = MSSA->getMemoryAccess(LaterInst); |
| if (!LaterMA) |
| return true; |
| |
| // Since we know LaterDef dominates LaterInst and EarlierInst dominates |
| // LaterInst, if LaterDef dominates EarlierInst then it can't occur between |
| // EarlierInst and LaterInst and neither can any other write that potentially |
| // clobbers LaterInst. |
| MemoryAccess *LaterDef; |
| if (ClobberCounter < EarlyCSEMssaOptCap) { |
| LaterDef = MSSA->getWalker()->getClobberingMemoryAccess(LaterInst); |
| ClobberCounter++; |
| } else |
| LaterDef = LaterMA->getDefiningAccess(); |
| |
| return MSSA->dominates(LaterDef, EarlierMA); |
| } |
| |
| bool EarlyCSE::isOperatingOnInvariantMemAt(Instruction *I, unsigned GenAt) { |
| // A location loaded from with an invariant_load is assumed to *never* change |
| // within the visible scope of the compilation. |
| if (auto *LI = dyn_cast<LoadInst>(I)) |
| if (LI->hasMetadata(LLVMContext::MD_invariant_load)) |
| return true; |
| |
| auto MemLocOpt = MemoryLocation::getOrNone(I); |
| if (!MemLocOpt) |
| // "target" intrinsic forms of loads aren't currently known to |
| // MemoryLocation::get. TODO |
| return false; |
| MemoryLocation MemLoc = *MemLocOpt; |
| if (!AvailableInvariants.count(MemLoc)) |
| return false; |
| |
| // Is the generation at which this became invariant older than the |
| // current one? |
| return AvailableInvariants.lookup(MemLoc) <= GenAt; |
| } |
| |
| bool EarlyCSE::handleBranchCondition(Instruction *CondInst, |
| const BranchInst *BI, const BasicBlock *BB, |
| const BasicBlock *Pred) { |
| assert(BI->isConditional() && "Should be a conditional branch!"); |
| assert(BI->getCondition() == CondInst && "Wrong condition?"); |
| assert(BI->getSuccessor(0) == BB || BI->getSuccessor(1) == BB); |
| auto *TorF = (BI->getSuccessor(0) == BB) |
| ? ConstantInt::getTrue(BB->getContext()) |
| : ConstantInt::getFalse(BB->getContext()); |
| auto MatchBinOp = [](Instruction *I, unsigned Opcode, Value *&LHS, |
| Value *&RHS) { |
| if (Opcode == Instruction::And && |
| match(I, m_LogicalAnd(m_Value(LHS), m_Value(RHS)))) |
| return true; |
| else if (Opcode == Instruction::Or && |
| match(I, m_LogicalOr(m_Value(LHS), m_Value(RHS)))) |
| return true; |
| return false; |
| }; |
| // If the condition is AND operation, we can propagate its operands into the |
| // true branch. If it is OR operation, we can propagate them into the false |
| // branch. |
| unsigned PropagateOpcode = |
| (BI->getSuccessor(0) == BB) ? Instruction::And : Instruction::Or; |
| |
| bool MadeChanges = false; |
| SmallVector<Instruction *, 4> WorkList; |
| SmallPtrSet<Instruction *, 4> Visited; |
| WorkList.push_back(CondInst); |
| while (!WorkList.empty()) { |
| Instruction *Curr = WorkList.pop_back_val(); |
| |
| AvailableValues.insert(Curr, TorF); |
| LLVM_DEBUG(dbgs() << "EarlyCSE CVP: Add conditional value for '" |
| << Curr->getName() << "' as " << *TorF << " in " |
| << BB->getName() << "\n"); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| } else { |
| // Replace all dominated uses with the known value. |
| if (unsigned Count = replaceDominatedUsesWith(Curr, TorF, DT, |
| BasicBlockEdge(Pred, BB))) { |
| NumCSECVP += Count; |
| MadeChanges = true; |
| } |
| } |
| |
| Value *LHS, *RHS; |
| if (MatchBinOp(Curr, PropagateOpcode, LHS, RHS)) |
| for (auto &Op : { LHS, RHS }) |
| if (Instruction *OPI = dyn_cast<Instruction>(Op)) |
| if (SimpleValue::canHandle(OPI) && Visited.insert(OPI).second) |
| WorkList.push_back(OPI); |
| } |
| |
| return MadeChanges; |
| } |
| |
| Value *EarlyCSE::getMatchingValue(LoadValue &InVal, ParseMemoryInst &MemInst, |
| unsigned CurrentGeneration) { |
| if (InVal.DefInst == nullptr) |
| return nullptr; |
| if (InVal.MatchingId != MemInst.getMatchingId()) |
| return nullptr; |
| // We don't yet handle removing loads with ordering of any kind. |
| if (MemInst.isVolatile() || !MemInst.isUnordered()) |
| return nullptr; |
| // We can't replace an atomic load with one which isn't also atomic. |
| if (MemInst.isLoad() && !InVal.IsAtomic && MemInst.isAtomic()) |
| return nullptr; |
| // The value V returned from this function is used differently depending |
| // on whether MemInst is a load or a store. If it's a load, we will replace |
| // MemInst with V, if it's a store, we will check if V is the same as the |
| // available value. |
| bool MemInstMatching = !MemInst.isLoad(); |
| Instruction *Matching = MemInstMatching ? MemInst.get() : InVal.DefInst; |
| Instruction *Other = MemInstMatching ? InVal.DefInst : MemInst.get(); |
| |
| // For stores check the result values before checking memory generation |
| // (otherwise isSameMemGeneration may crash). |
| Value *Result = MemInst.isStore() |
| ? getOrCreateResult(Matching, Other->getType()) |
| : nullptr; |
| if (MemInst.isStore() && InVal.DefInst != Result) |
| return nullptr; |
| |
| // Deal with non-target memory intrinsics. |
| bool MatchingNTI = isHandledNonTargetIntrinsic(Matching); |
| bool OtherNTI = isHandledNonTargetIntrinsic(Other); |
| if (OtherNTI != MatchingNTI) |
| return nullptr; |
| if (OtherNTI && MatchingNTI) { |
| if (!isNonTargetIntrinsicMatch(cast<IntrinsicInst>(InVal.DefInst), |
| cast<IntrinsicInst>(MemInst.get()))) |
| return nullptr; |
| } |
| |
| if (!isOperatingOnInvariantMemAt(MemInst.get(), InVal.Generation) && |
| !isSameMemGeneration(InVal.Generation, CurrentGeneration, InVal.DefInst, |
| MemInst.get())) |
| return nullptr; |
| |
| if (!Result) |
| Result = getOrCreateResult(Matching, Other->getType()); |
| return Result; |
| } |
| |
| bool EarlyCSE::overridingStores(const ParseMemoryInst &Earlier, |
| const ParseMemoryInst &Later) { |
| // Can we remove Earlier store because of Later store? |
| |
| assert(Earlier.isUnordered() && !Earlier.isVolatile() && |
| "Violated invariant"); |
| if (Earlier.getPointerOperand() != Later.getPointerOperand()) |
| return false; |
| if (Earlier.getMatchingId() != Later.getMatchingId()) |
| return false; |
| // At the moment, we don't remove ordered stores, but do remove |
| // unordered atomic stores. There's no special requirement (for |
| // unordered atomics) about removing atomic stores only in favor of |
| // other atomic stores since we were going to execute the non-atomic |
| // one anyway and the atomic one might never have become visible. |
| if (!Earlier.isUnordered() || !Later.isUnordered()) |
| return false; |
| |
| // Deal with non-target memory intrinsics. |
| bool ENTI = isHandledNonTargetIntrinsic(Earlier.get()); |
| bool LNTI = isHandledNonTargetIntrinsic(Later.get()); |
| if (ENTI && LNTI) |
| return isNonTargetIntrinsicMatch(cast<IntrinsicInst>(Earlier.get()), |
| cast<IntrinsicInst>(Later.get())); |
| |
| // Because of the check above, at least one of them is false. |
| // For now disallow matching intrinsics with non-intrinsics, |
| // so assume that the stores match if neither is an intrinsic. |
| return ENTI == LNTI; |
| } |
| |
| bool EarlyCSE::processNode(DomTreeNode *Node) { |
| bool Changed = false; |
| BasicBlock *BB = Node->getBlock(); |
| |
| // If this block has a single predecessor, then the predecessor is the parent |
| // of the domtree node and all of the live out memory values are still current |
| // in this block. If this block has multiple predecessors, then they could |
| // have invalidated the live-out memory values of our parent value. For now, |
| // just be conservative and invalidate memory if this block has multiple |
| // predecessors. |
| if (!BB->getSinglePredecessor()) |
| ++CurrentGeneration; |
| |
| // If this node has a single predecessor which ends in a conditional branch, |
| // we can infer the value of the branch condition given that we took this |
| // path. We need the single predecessor to ensure there's not another path |
| // which reaches this block where the condition might hold a different |
| // value. Since we're adding this to the scoped hash table (like any other |
| // def), it will have been popped if we encounter a future merge block. |
| if (BasicBlock *Pred = BB->getSinglePredecessor()) { |
| auto *BI = dyn_cast<BranchInst>(Pred->getTerminator()); |
| if (BI && BI->isConditional()) { |
| auto *CondInst = dyn_cast<Instruction>(BI->getCondition()); |
| if (CondInst && SimpleValue::canHandle(CondInst)) |
| Changed |= handleBranchCondition(CondInst, BI, BB, Pred); |
| } |
| } |
| |
| /// LastStore - Keep track of the last non-volatile store that we saw... for |
| /// as long as there in no instruction that reads memory. If we see a store |
| /// to the same location, we delete the dead store. This zaps trivial dead |
| /// stores which can occur in bitfield code among other things. |
| Instruction *LastStore = nullptr; |
| |
| // See if any instructions in the block can be eliminated. If so, do it. If |
| // not, add them to AvailableValues. |
| for (Instruction &Inst : make_early_inc_range(BB->getInstList())) { |
| // Dead instructions should just be removed. |
| if (isInstructionTriviallyDead(&Inst, &TLI)) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE DCE: " << Inst << '\n'); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| continue; |
| } |
| |
| salvageKnowledge(&Inst, &AC); |
| salvageDebugInfo(Inst); |
| removeMSSA(Inst); |
| Inst.eraseFromParent(); |
| Changed = true; |
| ++NumSimplify; |
| continue; |
| } |
| |
| // Skip assume intrinsics, they don't really have side effects (although |
| // they're marked as such to ensure preservation of control dependencies), |
| // and this pass will not bother with its removal. However, we should mark |
| // its condition as true for all dominated blocks. |
| if (auto *Assume = dyn_cast<AssumeInst>(&Inst)) { |
| auto *CondI = dyn_cast<Instruction>(Assume->getArgOperand(0)); |
| if (CondI && SimpleValue::canHandle(CondI)) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE considering assumption: " << Inst |
| << '\n'); |
| AvailableValues.insert(CondI, ConstantInt::getTrue(BB->getContext())); |
| } else |
| LLVM_DEBUG(dbgs() << "EarlyCSE skipping assumption: " << Inst << '\n'); |
| continue; |
| } |
| |
| // Likewise, noalias intrinsics don't actually write. |
| if (match(&Inst, |
| m_Intrinsic<Intrinsic::experimental_noalias_scope_decl>())) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE skipping noalias intrinsic: " << Inst |
| << '\n'); |
| continue; |
| } |
| |
| // Skip sideeffect intrinsics, for the same reason as assume intrinsics. |
| if (match(&Inst, m_Intrinsic<Intrinsic::sideeffect>())) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE skipping sideeffect: " << Inst << '\n'); |
| continue; |
| } |
| |
| // Skip pseudoprobe intrinsics, for the same reason as assume intrinsics. |
| if (match(&Inst, m_Intrinsic<Intrinsic::pseudoprobe>())) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE skipping pseudoprobe: " << Inst << '\n'); |
| continue; |
| } |
| |
| // We can skip all invariant.start intrinsics since they only read memory, |
| // and we can forward values across it. For invariant starts without |
| // invariant ends, we can use the fact that the invariantness never ends to |
| // start a scope in the current generaton which is true for all future |
| // generations. Also, we dont need to consume the last store since the |
| // semantics of invariant.start allow us to perform DSE of the last |
| // store, if there was a store following invariant.start. Consider: |
| // |
| // store 30, i8* p |
| // invariant.start(p) |
| // store 40, i8* p |
| // We can DSE the store to 30, since the store 40 to invariant location p |
| // causes undefined behaviour. |
| if (match(&Inst, m_Intrinsic<Intrinsic::invariant_start>())) { |
| // If there are any uses, the scope might end. |
| if (!Inst.use_empty()) |
| continue; |
| MemoryLocation MemLoc = |
| MemoryLocation::getForArgument(&cast<CallInst>(Inst), 1, TLI); |
| // Don't start a scope if we already have a better one pushed |
| if (!AvailableInvariants.count(MemLoc)) |
| AvailableInvariants.insert(MemLoc, CurrentGeneration); |
| continue; |
| } |
| |
| if (isGuard(&Inst)) { |
| if (auto *CondI = |
| dyn_cast<Instruction>(cast<CallInst>(Inst).getArgOperand(0))) { |
| if (SimpleValue::canHandle(CondI)) { |
| // Do we already know the actual value of this condition? |
| if (auto *KnownCond = AvailableValues.lookup(CondI)) { |
| // Is the condition known to be true? |
| if (isa<ConstantInt>(KnownCond) && |
| cast<ConstantInt>(KnownCond)->isOne()) { |
| LLVM_DEBUG(dbgs() |
| << "EarlyCSE removing guard: " << Inst << '\n'); |
| salvageKnowledge(&Inst, &AC); |
| removeMSSA(Inst); |
| Inst.eraseFromParent(); |
| Changed = true; |
| continue; |
| } else |
| // Use the known value if it wasn't true. |
| cast<CallInst>(Inst).setArgOperand(0, KnownCond); |
| } |
| // The condition we're on guarding here is true for all dominated |
| // locations. |
| AvailableValues.insert(CondI, ConstantInt::getTrue(BB->getContext())); |
| } |
| } |
| |
| // Guard intrinsics read all memory, but don't write any memory. |
| // Accordingly, don't update the generation but consume the last store (to |
| // avoid an incorrect DSE). |
| LastStore = nullptr; |
| continue; |
| } |
| |
| // If the instruction can be simplified (e.g. X+0 = X) then replace it with |
| // its simpler value. |
| if (Value *V = SimplifyInstruction(&Inst, SQ)) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE Simplify: " << Inst << " to: " << *V |
| << '\n'); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| } else { |
| bool Killed = false; |
| if (!Inst.use_empty()) { |
| Inst.replaceAllUsesWith(V); |
| Changed = true; |
| } |
| if (isInstructionTriviallyDead(&Inst, &TLI)) { |
| salvageKnowledge(&Inst, &AC); |
| removeMSSA(Inst); |
| Inst.eraseFromParent(); |
| Changed = true; |
| Killed = true; |
| } |
| if (Changed) |
| ++NumSimplify; |
| if (Killed) |
| continue; |
| } |
| } |
| |
| // If this is a simple instruction that we can value number, process it. |
| if (SimpleValue::canHandle(&Inst)) { |
| // See if the instruction has an available value. If so, use it. |
| if (Value *V = AvailableValues.lookup(&Inst)) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE CSE: " << Inst << " to: " << *V |
| << '\n'); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| continue; |
| } |
| if (auto *I = dyn_cast<Instruction>(V)) |
| I->andIRFlags(&Inst); |
| Inst.replaceAllUsesWith(V); |
| salvageKnowledge(&Inst, &AC); |
| removeMSSA(Inst); |
| Inst.eraseFromParent(); |
| Changed = true; |
| ++NumCSE; |
| continue; |
| } |
| |
| // Otherwise, just remember that this value is available. |
| AvailableValues.insert(&Inst, &Inst); |
| continue; |
| } |
| |
| ParseMemoryInst MemInst(&Inst, TTI); |
| // If this is a non-volatile load, process it. |
| if (MemInst.isValid() && MemInst.isLoad()) { |
| // (conservatively) we can't peak past the ordering implied by this |
| // operation, but we can add this load to our set of available values |
| if (MemInst.isVolatile() || !MemInst.isUnordered()) { |
| LastStore = nullptr; |
| ++CurrentGeneration; |
| } |
| |
| if (MemInst.isInvariantLoad()) { |
| // If we pass an invariant load, we know that memory location is |
| // indefinitely constant from the moment of first dereferenceability. |
| // We conservatively treat the invariant_load as that moment. If we |
| // pass a invariant load after already establishing a scope, don't |
| // restart it since we want to preserve the earliest point seen. |
| auto MemLoc = MemoryLocation::get(&Inst); |
| if (!AvailableInvariants.count(MemLoc)) |
| AvailableInvariants.insert(MemLoc, CurrentGeneration); |
| } |
| |
| // If we have an available version of this load, and if it is the right |
| // generation or the load is known to be from an invariant location, |
| // replace this instruction. |
| // |
| // If either the dominating load or the current load are invariant, then |
| // we can assume the current load loads the same value as the dominating |
| // load. |
| LoadValue InVal = AvailableLoads.lookup(MemInst.getPointerOperand()); |
| if (Value *Op = getMatchingValue(InVal, MemInst, CurrentGeneration)) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE CSE LOAD: " << Inst |
| << " to: " << *InVal.DefInst << '\n'); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| continue; |
| } |
| if (!Inst.use_empty()) |
| Inst.replaceAllUsesWith(Op); |
| salvageKnowledge(&Inst, &AC); |
| removeMSSA(Inst); |
| Inst.eraseFromParent(); |
| Changed = true; |
| ++NumCSELoad; |
| continue; |
| } |
| |
| // Otherwise, remember that we have this instruction. |
| AvailableLoads.insert(MemInst.getPointerOperand(), |
| LoadValue(&Inst, CurrentGeneration, |
| MemInst.getMatchingId(), |
| MemInst.isAtomic())); |
| LastStore = nullptr; |
| continue; |
| } |
| |
| // If this instruction may read from memory or throw (and potentially read |
| // from memory in the exception handler), forget LastStore. Load/store |
| // intrinsics will indicate both a read and a write to memory. The target |
| // may override this (e.g. so that a store intrinsic does not read from |
| // memory, and thus will be treated the same as a regular store for |
| // commoning purposes). |
| if ((Inst.mayReadFromMemory() || Inst.mayThrow()) && |
| !(MemInst.isValid() && !MemInst.mayReadFromMemory())) |
| LastStore = nullptr; |
| |
| // If this is a read-only call, process it. |
| if (CallValue::canHandle(&Inst)) { |
| // If we have an available version of this call, and if it is the right |
| // generation, replace this instruction. |
| std::pair<Instruction *, unsigned> InVal = AvailableCalls.lookup(&Inst); |
| if (InVal.first != nullptr && |
| isSameMemGeneration(InVal.second, CurrentGeneration, InVal.first, |
| &Inst)) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE CSE CALL: " << Inst |
| << " to: " << *InVal.first << '\n'); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| continue; |
| } |
| if (!Inst.use_empty()) |
| Inst.replaceAllUsesWith(InVal.first); |
| salvageKnowledge(&Inst, &AC); |
| removeMSSA(Inst); |
| Inst.eraseFromParent(); |
| Changed = true; |
| ++NumCSECall; |
| continue; |
| } |
| |
| // Otherwise, remember that we have this instruction. |
| AvailableCalls.insert(&Inst, std::make_pair(&Inst, CurrentGeneration)); |
| continue; |
| } |
| |
| // A release fence requires that all stores complete before it, but does |
| // not prevent the reordering of following loads 'before' the fence. As a |
| // result, we don't need to consider it as writing to memory and don't need |
| // to advance the generation. We do need to prevent DSE across the fence, |
| // but that's handled above. |
| if (auto *FI = dyn_cast<FenceInst>(&Inst)) |
| if (FI->getOrdering() == AtomicOrdering::Release) { |
| assert(Inst.mayReadFromMemory() && "relied on to prevent DSE above"); |
| continue; |
| } |
| |
| // write back DSE - If we write back the same value we just loaded from |
| // the same location and haven't passed any intervening writes or ordering |
| // operations, we can remove the write. The primary benefit is in allowing |
| // the available load table to remain valid and value forward past where |
| // the store originally was. |
| if (MemInst.isValid() && MemInst.isStore()) { |
| LoadValue InVal = AvailableLoads.lookup(MemInst.getPointerOperand()); |
| if (InVal.DefInst && |
| InVal.DefInst == getMatchingValue(InVal, MemInst, CurrentGeneration)) { |
| // It is okay to have a LastStore to a different pointer here if MemorySSA |
| // tells us that the load and store are from the same memory generation. |
| // In that case, LastStore should keep its present value since we're |
| // removing the current store. |
| assert((!LastStore || |
| ParseMemoryInst(LastStore, TTI).getPointerOperand() == |
| MemInst.getPointerOperand() || |
| MSSA) && |
| "can't have an intervening store if not using MemorySSA!"); |
| LLVM_DEBUG(dbgs() << "EarlyCSE DSE (writeback): " << Inst << '\n'); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| continue; |
| } |
| salvageKnowledge(&Inst, &AC); |
| removeMSSA(Inst); |
| Inst.eraseFromParent(); |
| Changed = true; |
| ++NumDSE; |
| // We can avoid incrementing the generation count since we were able |
| // to eliminate this store. |
| continue; |
| } |
| } |
| |
| // Okay, this isn't something we can CSE at all. Check to see if it is |
| // something that could modify memory. If so, our available memory values |
| // cannot be used so bump the generation count. |
| if (Inst.mayWriteToMemory()) { |
| ++CurrentGeneration; |
| |
| if (MemInst.isValid() && MemInst.isStore()) { |
| // We do a trivial form of DSE if there are two stores to the same |
| // location with no intervening loads. Delete the earlier store. |
| if (LastStore) { |
| if (overridingStores(ParseMemoryInst(LastStore, TTI), MemInst)) { |
| LLVM_DEBUG(dbgs() << "EarlyCSE DEAD STORE: " << *LastStore |
| << " due to: " << Inst << '\n'); |
| if (!DebugCounter::shouldExecute(CSECounter)) { |
| LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n"); |
| } else { |
| salvageKnowledge(&Inst, &AC); |
| removeMSSA(*LastStore); |
| LastStore->eraseFromParent(); |
| Changed = true; |
| ++NumDSE; |
| LastStore = nullptr; |
| } |
| } |
| // fallthrough - we can exploit information about this store |
| } |
| |
| // Okay, we just invalidated anything we knew about loaded values. Try |
| // to salvage *something* by remembering that the stored value is a live |
| // version of the pointer. It is safe to forward from volatile stores |
| // to non-volatile loads, so we don't have to check for volatility of |
| // the store. |
| AvailableLoads.insert(MemInst.getPointerOperand(), |
| LoadValue(&Inst, CurrentGeneration, |
| MemInst.getMatchingId(), |
| MemInst.isAtomic())); |
| |
| // Remember that this was the last unordered store we saw for DSE. We |
| // don't yet handle DSE on ordered or volatile stores since we don't |
| // have a good way to model the ordering requirement for following |
| // passes once the store is removed. We could insert a fence, but |
| // since fences are slightly stronger than stores in their ordering, |
| // it's not clear this is a profitable transform. Another option would |
| // be to merge the ordering with that of the post dominating store. |
| if (MemInst.isUnordered() && !MemInst.isVolatile()) |
| LastStore = &Inst; |
| else |
| LastStore = nullptr; |
| } |
| } |
| } |
| |
| return Changed; |
| } |
| |
| bool EarlyCSE::run() { |
| // Note, deque is being used here because there is significant performance |
| // gains over vector when the container becomes very large due to the |
| // specific access patterns. For more information see the mailing list |
| // discussion on this: |
| // http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20120116/135228.html |
| std::deque<StackNode *> nodesToProcess; |
| |
| bool Changed = false; |
| |
| // Process the root node. |
| nodesToProcess.push_back(new StackNode( |
| AvailableValues, AvailableLoads, AvailableInvariants, AvailableCalls, |
| CurrentGeneration, DT.getRootNode(), |
| DT.getRootNode()->begin(), DT.getRootNode()->end())); |
| |
| assert(!CurrentGeneration && "Create a new EarlyCSE instance to rerun it."); |
| |
| // Process the stack. |
| while (!nodesToProcess.empty()) { |
| // Grab the first item off the stack. Set the current generation, remove |
| // the node from the stack, and process it. |
| StackNode *NodeToProcess = nodesToProcess.back(); |
| |
| // Initialize class members. |
| CurrentGeneration = NodeToProcess->currentGeneration(); |
| |
| // Check if the node needs to be processed. |
| if (!NodeToProcess->isProcessed()) { |
| // Process the node. |
| Changed |= processNode(NodeToProcess->node()); |
| NodeToProcess->childGeneration(CurrentGeneration); |
| NodeToProcess->process(); |
| } else if (NodeToProcess->childIter() != NodeToProcess->end()) { |
| // Push the next child onto the stack. |
| DomTreeNode *child = NodeToProcess->nextChild(); |
| nodesToProcess.push_back( |
| new StackNode(AvailableValues, AvailableLoads, AvailableInvariants, |
| AvailableCalls, NodeToProcess->childGeneration(), |
| child, child->begin(), child->end())); |
| } else { |
| // It has been processed, and there are no more children to process, |
| // so delete it and pop it off the stack. |
| delete NodeToProcess; |
| nodesToProcess.pop_back(); |
| } |
| } // while (!nodes...) |
| |
| return Changed; |
| } |
| |
| PreservedAnalyses EarlyCSEPass::run(Function &F, |
| FunctionAnalysisManager &AM) { |
| auto &TLI = AM.getResult<TargetLibraryAnalysis>(F); |
| auto &TTI = AM.getResult<TargetIRAnalysis>(F); |
| auto &DT = AM.getResult<DominatorTreeAnalysis>(F); |
| auto &AC = AM.getResult<AssumptionAnalysis>(F); |
| auto *MSSA = |
| UseMemorySSA ? &AM.getResult<MemorySSAAnalysis>(F).getMSSA() : nullptr; |
| |
| EarlyCSE CSE(F.getParent()->getDataLayout(), TLI, TTI, DT, AC, MSSA); |
| |
| if (!CSE.run()) |
| return PreservedAnalyses::all(); |
| |
| PreservedAnalyses PA; |
| PA.preserveSet<CFGAnalyses>(); |
| if (UseMemorySSA) |
| PA.preserve<MemorySSAAnalysis>(); |
| return PA; |
| } |
| |
| void EarlyCSEPass::printPipeline( |
| raw_ostream &OS, function_ref<StringRef(StringRef)> MapClassName2PassName) { |
| static_cast<PassInfoMixin<EarlyCSEPass> *>(this)->printPipeline( |
| OS, MapClassName2PassName); |
| OS << "<"; |
| if (UseMemorySSA) |
| OS << "memssa"; |
| OS << ">"; |
| } |
| |
| namespace { |
| |
| /// A simple and fast domtree-based CSE pass. |
| /// |
| /// This pass does a simple depth-first walk over the dominator tree, |
| /// eliminating trivially redundant instructions and using instsimplify to |
| /// canonicalize things as it goes. It is intended to be fast and catch obvious |
| /// cases so that instcombine and other passes are more effective. It is |
| /// expected that a later pass of GVN will catch the interesting/hard cases. |
| template<bool UseMemorySSA> |
| class EarlyCSELegacyCommonPass : public FunctionPass { |
| public: |
| static char ID; |
| |
| EarlyCSELegacyCommonPass() : FunctionPass(ID) { |
| if (UseMemorySSA) |
| initializeEarlyCSEMemSSALegacyPassPass(*PassRegistry::getPassRegistry()); |
| else |
| initializeEarlyCSELegacyPassPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| bool runOnFunction(Function &F) override { |
| if (skipFunction(F)) |
| return false; |
| |
| auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F); |
| auto &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F); |
| auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree(); |
| auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F); |
| auto *MSSA = |
| UseMemorySSA ? &getAnalysis<MemorySSAWrapperPass>().getMSSA() : nullptr; |
| |
| EarlyCSE CSE(F.getParent()->getDataLayout(), TLI, TTI, DT, AC, MSSA); |
| |
| return CSE.run(); |
| } |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| AU.addRequired<AssumptionCacheTracker>(); |
| AU.addRequired<DominatorTreeWrapperPass>(); |
| AU.addRequired<TargetLibraryInfoWrapperPass>(); |
| AU.addRequired<TargetTransformInfoWrapperPass>(); |
| if (UseMemorySSA) { |
| AU.addRequired<AAResultsWrapperPass>(); |
| AU.addRequired<MemorySSAWrapperPass>(); |
| AU.addPreserved<MemorySSAWrapperPass>(); |
| } |
| AU.addPreserved<GlobalsAAWrapperPass>(); |
| AU.addPreserved<AAResultsWrapperPass>(); |
| AU.setPreservesCFG(); |
| } |
| }; |
| |
| } // end anonymous namespace |
| |
| using EarlyCSELegacyPass = EarlyCSELegacyCommonPass</*UseMemorySSA=*/false>; |
| |
| template<> |
| char EarlyCSELegacyPass::ID = 0; |
| |
| INITIALIZE_PASS_BEGIN(EarlyCSELegacyPass, "early-cse", "Early CSE", false, |
| false) |
| INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker) |
| INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass) |
| INITIALIZE_PASS_END(EarlyCSELegacyPass, "early-cse", "Early CSE", false, false) |
| |
| using EarlyCSEMemSSALegacyPass = |
| EarlyCSELegacyCommonPass</*UseMemorySSA=*/true>; |
| |
| template<> |
| char EarlyCSEMemSSALegacyPass::ID = 0; |
| |
| FunctionPass *llvm::createEarlyCSEPass(bool UseMemorySSA) { |
| if (UseMemorySSA) |
| return new EarlyCSEMemSSALegacyPass(); |
| else |
| return new EarlyCSELegacyPass(); |
| } |
| |
| INITIALIZE_PASS_BEGIN(EarlyCSEMemSSALegacyPass, "early-cse-memssa", |
| "Early CSE w/ MemorySSA", false, false) |
| INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker) |
| INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass) |
| INITIALIZE_PASS_END(EarlyCSEMemSSALegacyPass, "early-cse-memssa", |
| "Early CSE w/ MemorySSA", false, false) |