| //===- LowerMemIntrinsics.cpp ----------------------------------*- C++ -*--===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/Utils/LowerMemIntrinsics.h" |
| #include "llvm/Analysis/ScalarEvolution.h" |
| #include "llvm/Analysis/TargetTransformInfo.h" |
| #include "llvm/IR/IRBuilder.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/MDBuilder.h" |
| #include "llvm/Transforms/Utils/BasicBlockUtils.h" |
| #include <optional> |
| |
| using namespace llvm; |
| |
| void llvm::createMemCpyLoopKnownSize( |
| Instruction *InsertBefore, Value *SrcAddr, Value *DstAddr, |
| ConstantInt *CopyLen, Align SrcAlign, Align DstAlign, bool SrcIsVolatile, |
| bool DstIsVolatile, bool CanOverlap, const TargetTransformInfo &TTI, |
| std::optional<uint32_t> AtomicElementSize) { |
| // No need to expand zero length copies. |
| if (CopyLen->isZero()) |
| return; |
| |
| BasicBlock *PreLoopBB = InsertBefore->getParent(); |
| BasicBlock *PostLoopBB = nullptr; |
| Function *ParentFunc = PreLoopBB->getParent(); |
| LLVMContext &Ctx = PreLoopBB->getContext(); |
| const DataLayout &DL = ParentFunc->getParent()->getDataLayout(); |
| MDBuilder MDB(Ctx); |
| MDNode *NewDomain = MDB.createAnonymousAliasScopeDomain("MemCopyDomain"); |
| StringRef Name = "MemCopyAliasScope"; |
| MDNode *NewScope = MDB.createAnonymousAliasScope(NewDomain, Name); |
| |
| unsigned SrcAS = cast<PointerType>(SrcAddr->getType())->getAddressSpace(); |
| unsigned DstAS = cast<PointerType>(DstAddr->getType())->getAddressSpace(); |
| |
| Type *TypeOfCopyLen = CopyLen->getType(); |
| Type *LoopOpType = TTI.getMemcpyLoopLoweringType( |
| Ctx, CopyLen, SrcAS, DstAS, SrcAlign.value(), DstAlign.value(), |
| AtomicElementSize); |
| assert((!AtomicElementSize || !LoopOpType->isVectorTy()) && |
| "Atomic memcpy lowering is not supported for vector operand type"); |
| |
| unsigned LoopOpSize = DL.getTypeStoreSize(LoopOpType); |
| assert((!AtomicElementSize || LoopOpSize % *AtomicElementSize == 0) && |
| "Atomic memcpy lowering is not supported for selected operand size"); |
| |
| uint64_t LoopEndCount = CopyLen->getZExtValue() / LoopOpSize; |
| |
| if (LoopEndCount != 0) { |
| // Split |
| PostLoopBB = PreLoopBB->splitBasicBlock(InsertBefore, "memcpy-split"); |
| BasicBlock *LoopBB = |
| BasicBlock::Create(Ctx, "load-store-loop", ParentFunc, PostLoopBB); |
| PreLoopBB->getTerminator()->setSuccessor(0, LoopBB); |
| |
| IRBuilder<> PLBuilder(PreLoopBB->getTerminator()); |
| |
| // Cast the Src and Dst pointers to pointers to the loop operand type (if |
| // needed). |
| PointerType *SrcOpType = PointerType::get(LoopOpType, SrcAS); |
| PointerType *DstOpType = PointerType::get(LoopOpType, DstAS); |
| if (SrcAddr->getType() != SrcOpType) { |
| SrcAddr = PLBuilder.CreateBitCast(SrcAddr, SrcOpType); |
| } |
| if (DstAddr->getType() != DstOpType) { |
| DstAddr = PLBuilder.CreateBitCast(DstAddr, DstOpType); |
| } |
| |
| Align PartDstAlign(commonAlignment(DstAlign, LoopOpSize)); |
| Align PartSrcAlign(commonAlignment(SrcAlign, LoopOpSize)); |
| |
| IRBuilder<> LoopBuilder(LoopBB); |
| PHINode *LoopIndex = LoopBuilder.CreatePHI(TypeOfCopyLen, 2, "loop-index"); |
| LoopIndex->addIncoming(ConstantInt::get(TypeOfCopyLen, 0U), PreLoopBB); |
| // Loop Body |
| Value *SrcGEP = |
| LoopBuilder.CreateInBoundsGEP(LoopOpType, SrcAddr, LoopIndex); |
| LoadInst *Load = LoopBuilder.CreateAlignedLoad(LoopOpType, SrcGEP, |
| PartSrcAlign, SrcIsVolatile); |
| if (!CanOverlap) { |
| // Set alias scope for loads. |
| Load->setMetadata(LLVMContext::MD_alias_scope, |
| MDNode::get(Ctx, NewScope)); |
| } |
| Value *DstGEP = |
| LoopBuilder.CreateInBoundsGEP(LoopOpType, DstAddr, LoopIndex); |
| StoreInst *Store = LoopBuilder.CreateAlignedStore( |
| Load, DstGEP, PartDstAlign, DstIsVolatile); |
| if (!CanOverlap) { |
| // Indicate that stores don't overlap loads. |
| Store->setMetadata(LLVMContext::MD_noalias, MDNode::get(Ctx, NewScope)); |
| } |
| if (AtomicElementSize) { |
| Load->setAtomic(AtomicOrdering::Unordered); |
| Store->setAtomic(AtomicOrdering::Unordered); |
| } |
| Value *NewIndex = |
| LoopBuilder.CreateAdd(LoopIndex, ConstantInt::get(TypeOfCopyLen, 1U)); |
| LoopIndex->addIncoming(NewIndex, LoopBB); |
| |
| // Create the loop branch condition. |
| Constant *LoopEndCI = ConstantInt::get(TypeOfCopyLen, LoopEndCount); |
| LoopBuilder.CreateCondBr(LoopBuilder.CreateICmpULT(NewIndex, LoopEndCI), |
| LoopBB, PostLoopBB); |
| } |
| |
| uint64_t BytesCopied = LoopEndCount * LoopOpSize; |
| uint64_t RemainingBytes = CopyLen->getZExtValue() - BytesCopied; |
| if (RemainingBytes) { |
| IRBuilder<> RBuilder(PostLoopBB ? PostLoopBB->getFirstNonPHI() |
| : InsertBefore); |
| |
| SmallVector<Type *, 5> RemainingOps; |
| TTI.getMemcpyLoopResidualLoweringType(RemainingOps, Ctx, RemainingBytes, |
| SrcAS, DstAS, SrcAlign.value(), |
| DstAlign.value(), AtomicElementSize); |
| |
| for (auto *OpTy : RemainingOps) { |
| Align PartSrcAlign(commonAlignment(SrcAlign, BytesCopied)); |
| Align PartDstAlign(commonAlignment(DstAlign, BytesCopied)); |
| |
| // Calculate the new index |
| unsigned OperandSize = DL.getTypeStoreSize(OpTy); |
| assert( |
| (!AtomicElementSize || OperandSize % *AtomicElementSize == 0) && |
| "Atomic memcpy lowering is not supported for selected operand size"); |
| |
| uint64_t GepIndex = BytesCopied / OperandSize; |
| assert(GepIndex * OperandSize == BytesCopied && |
| "Division should have no Remainder!"); |
| // Cast source to operand type and load |
| PointerType *SrcPtrType = PointerType::get(OpTy, SrcAS); |
| Value *CastedSrc = SrcAddr->getType() == SrcPtrType |
| ? SrcAddr |
| : RBuilder.CreateBitCast(SrcAddr, SrcPtrType); |
| Value *SrcGEP = RBuilder.CreateInBoundsGEP( |
| OpTy, CastedSrc, ConstantInt::get(TypeOfCopyLen, GepIndex)); |
| LoadInst *Load = |
| RBuilder.CreateAlignedLoad(OpTy, SrcGEP, PartSrcAlign, SrcIsVolatile); |
| if (!CanOverlap) { |
| // Set alias scope for loads. |
| Load->setMetadata(LLVMContext::MD_alias_scope, |
| MDNode::get(Ctx, NewScope)); |
| } |
| // Cast destination to operand type and store. |
| PointerType *DstPtrType = PointerType::get(OpTy, DstAS); |
| Value *CastedDst = DstAddr->getType() == DstPtrType |
| ? DstAddr |
| : RBuilder.CreateBitCast(DstAddr, DstPtrType); |
| Value *DstGEP = RBuilder.CreateInBoundsGEP( |
| OpTy, CastedDst, ConstantInt::get(TypeOfCopyLen, GepIndex)); |
| StoreInst *Store = RBuilder.CreateAlignedStore(Load, DstGEP, PartDstAlign, |
| DstIsVolatile); |
| if (!CanOverlap) { |
| // Indicate that stores don't overlap loads. |
| Store->setMetadata(LLVMContext::MD_noalias, MDNode::get(Ctx, NewScope)); |
| } |
| if (AtomicElementSize) { |
| Load->setAtomic(AtomicOrdering::Unordered); |
| Store->setAtomic(AtomicOrdering::Unordered); |
| } |
| BytesCopied += OperandSize; |
| } |
| } |
| assert(BytesCopied == CopyLen->getZExtValue() && |
| "Bytes copied should match size in the call!"); |
| } |
| |
| void llvm::createMemCpyLoopUnknownSize( |
| Instruction *InsertBefore, Value *SrcAddr, Value *DstAddr, Value *CopyLen, |
| Align SrcAlign, Align DstAlign, bool SrcIsVolatile, bool DstIsVolatile, |
| bool CanOverlap, const TargetTransformInfo &TTI, |
| std::optional<uint32_t> AtomicElementSize) { |
| BasicBlock *PreLoopBB = InsertBefore->getParent(); |
| BasicBlock *PostLoopBB = |
| PreLoopBB->splitBasicBlock(InsertBefore, "post-loop-memcpy-expansion"); |
| |
| Function *ParentFunc = PreLoopBB->getParent(); |
| const DataLayout &DL = ParentFunc->getParent()->getDataLayout(); |
| LLVMContext &Ctx = PreLoopBB->getContext(); |
| MDBuilder MDB(Ctx); |
| MDNode *NewDomain = MDB.createAnonymousAliasScopeDomain("MemCopyDomain"); |
| StringRef Name = "MemCopyAliasScope"; |
| MDNode *NewScope = MDB.createAnonymousAliasScope(NewDomain, Name); |
| |
| unsigned SrcAS = cast<PointerType>(SrcAddr->getType())->getAddressSpace(); |
| unsigned DstAS = cast<PointerType>(DstAddr->getType())->getAddressSpace(); |
| |
| Type *LoopOpType = TTI.getMemcpyLoopLoweringType( |
| Ctx, CopyLen, SrcAS, DstAS, SrcAlign.value(), DstAlign.value(), |
| AtomicElementSize); |
| assert((!AtomicElementSize || !LoopOpType->isVectorTy()) && |
| "Atomic memcpy lowering is not supported for vector operand type"); |
| unsigned LoopOpSize = DL.getTypeStoreSize(LoopOpType); |
| assert((!AtomicElementSize || LoopOpSize % *AtomicElementSize == 0) && |
| "Atomic memcpy lowering is not supported for selected operand size"); |
| |
| IRBuilder<> PLBuilder(PreLoopBB->getTerminator()); |
| |
| PointerType *SrcOpType = PointerType::get(LoopOpType, SrcAS); |
| PointerType *DstOpType = PointerType::get(LoopOpType, DstAS); |
| if (SrcAddr->getType() != SrcOpType) { |
| SrcAddr = PLBuilder.CreateBitCast(SrcAddr, SrcOpType); |
| } |
| if (DstAddr->getType() != DstOpType) { |
| DstAddr = PLBuilder.CreateBitCast(DstAddr, DstOpType); |
| } |
| |
| // Calculate the loop trip count, and remaining bytes to copy after the loop. |
| Type *CopyLenType = CopyLen->getType(); |
| IntegerType *ILengthType = dyn_cast<IntegerType>(CopyLenType); |
| assert(ILengthType && |
| "expected size argument to memcpy to be an integer type!"); |
| Type *Int8Type = Type::getInt8Ty(Ctx); |
| bool LoopOpIsInt8 = LoopOpType == Int8Type; |
| ConstantInt *CILoopOpSize = ConstantInt::get(ILengthType, LoopOpSize); |
| Value *RuntimeLoopCount = LoopOpIsInt8 ? |
| CopyLen : |
| PLBuilder.CreateUDiv(CopyLen, CILoopOpSize); |
| BasicBlock *LoopBB = |
| BasicBlock::Create(Ctx, "loop-memcpy-expansion", ParentFunc, PostLoopBB); |
| IRBuilder<> LoopBuilder(LoopBB); |
| |
| Align PartSrcAlign(commonAlignment(SrcAlign, LoopOpSize)); |
| Align PartDstAlign(commonAlignment(DstAlign, LoopOpSize)); |
| |
| PHINode *LoopIndex = LoopBuilder.CreatePHI(CopyLenType, 2, "loop-index"); |
| LoopIndex->addIncoming(ConstantInt::get(CopyLenType, 0U), PreLoopBB); |
| |
| Value *SrcGEP = LoopBuilder.CreateInBoundsGEP(LoopOpType, SrcAddr, LoopIndex); |
| LoadInst *Load = LoopBuilder.CreateAlignedLoad(LoopOpType, SrcGEP, |
| PartSrcAlign, SrcIsVolatile); |
| if (!CanOverlap) { |
| // Set alias scope for loads. |
| Load->setMetadata(LLVMContext::MD_alias_scope, MDNode::get(Ctx, NewScope)); |
| } |
| Value *DstGEP = LoopBuilder.CreateInBoundsGEP(LoopOpType, DstAddr, LoopIndex); |
| StoreInst *Store = |
| LoopBuilder.CreateAlignedStore(Load, DstGEP, PartDstAlign, DstIsVolatile); |
| if (!CanOverlap) { |
| // Indicate that stores don't overlap loads. |
| Store->setMetadata(LLVMContext::MD_noalias, MDNode::get(Ctx, NewScope)); |
| } |
| if (AtomicElementSize) { |
| Load->setAtomic(AtomicOrdering::Unordered); |
| Store->setAtomic(AtomicOrdering::Unordered); |
| } |
| Value *NewIndex = |
| LoopBuilder.CreateAdd(LoopIndex, ConstantInt::get(CopyLenType, 1U)); |
| LoopIndex->addIncoming(NewIndex, LoopBB); |
| |
| bool requiresResidual = |
| !LoopOpIsInt8 && !(AtomicElementSize && LoopOpSize == AtomicElementSize); |
| if (requiresResidual) { |
| Type *ResLoopOpType = AtomicElementSize |
| ? Type::getIntNTy(Ctx, *AtomicElementSize * 8) |
| : Int8Type; |
| unsigned ResLoopOpSize = DL.getTypeStoreSize(ResLoopOpType); |
| assert((ResLoopOpSize == AtomicElementSize ? *AtomicElementSize : 1) && |
| "Store size is expected to match type size"); |
| |
| // Add in the |
| Value *RuntimeResidual = PLBuilder.CreateURem(CopyLen, CILoopOpSize); |
| Value *RuntimeBytesCopied = PLBuilder.CreateSub(CopyLen, RuntimeResidual); |
| |
| // Loop body for the residual copy. |
| BasicBlock *ResLoopBB = BasicBlock::Create(Ctx, "loop-memcpy-residual", |
| PreLoopBB->getParent(), |
| PostLoopBB); |
| // Residual loop header. |
| BasicBlock *ResHeaderBB = BasicBlock::Create( |
| Ctx, "loop-memcpy-residual-header", PreLoopBB->getParent(), nullptr); |
| |
| // Need to update the pre-loop basic block to branch to the correct place. |
| // branch to the main loop if the count is non-zero, branch to the residual |
| // loop if the copy size is smaller then 1 iteration of the main loop but |
| // non-zero and finally branch to after the residual loop if the memcpy |
| // size is zero. |
| ConstantInt *Zero = ConstantInt::get(ILengthType, 0U); |
| PLBuilder.CreateCondBr(PLBuilder.CreateICmpNE(RuntimeLoopCount, Zero), |
| LoopBB, ResHeaderBB); |
| PreLoopBB->getTerminator()->eraseFromParent(); |
| |
| LoopBuilder.CreateCondBr( |
| LoopBuilder.CreateICmpULT(NewIndex, RuntimeLoopCount), LoopBB, |
| ResHeaderBB); |
| |
| // Determine if we need to branch to the residual loop or bypass it. |
| IRBuilder<> RHBuilder(ResHeaderBB); |
| RHBuilder.CreateCondBr(RHBuilder.CreateICmpNE(RuntimeResidual, Zero), |
| ResLoopBB, PostLoopBB); |
| |
| // Copy the residual with single byte load/store loop. |
| IRBuilder<> ResBuilder(ResLoopBB); |
| PHINode *ResidualIndex = |
| ResBuilder.CreatePHI(CopyLenType, 2, "residual-loop-index"); |
| ResidualIndex->addIncoming(Zero, ResHeaderBB); |
| |
| Value *SrcAsResLoopOpType = ResBuilder.CreateBitCast( |
| SrcAddr, PointerType::get(ResLoopOpType, SrcAS)); |
| Value *DstAsResLoopOpType = ResBuilder.CreateBitCast( |
| DstAddr, PointerType::get(ResLoopOpType, DstAS)); |
| Value *FullOffset = ResBuilder.CreateAdd(RuntimeBytesCopied, ResidualIndex); |
| Value *SrcGEP = ResBuilder.CreateInBoundsGEP( |
| ResLoopOpType, SrcAsResLoopOpType, FullOffset); |
| LoadInst *Load = ResBuilder.CreateAlignedLoad(ResLoopOpType, SrcGEP, |
| PartSrcAlign, SrcIsVolatile); |
| if (!CanOverlap) { |
| // Set alias scope for loads. |
| Load->setMetadata(LLVMContext::MD_alias_scope, |
| MDNode::get(Ctx, NewScope)); |
| } |
| Value *DstGEP = ResBuilder.CreateInBoundsGEP( |
| ResLoopOpType, DstAsResLoopOpType, FullOffset); |
| StoreInst *Store = ResBuilder.CreateAlignedStore(Load, DstGEP, PartDstAlign, |
| DstIsVolatile); |
| if (!CanOverlap) { |
| // Indicate that stores don't overlap loads. |
| Store->setMetadata(LLVMContext::MD_noalias, MDNode::get(Ctx, NewScope)); |
| } |
| if (AtomicElementSize) { |
| Load->setAtomic(AtomicOrdering::Unordered); |
| Store->setAtomic(AtomicOrdering::Unordered); |
| } |
| Value *ResNewIndex = ResBuilder.CreateAdd( |
| ResidualIndex, ConstantInt::get(CopyLenType, ResLoopOpSize)); |
| ResidualIndex->addIncoming(ResNewIndex, ResLoopBB); |
| |
| // Create the loop branch condition. |
| ResBuilder.CreateCondBr( |
| ResBuilder.CreateICmpULT(ResNewIndex, RuntimeResidual), ResLoopBB, |
| PostLoopBB); |
| } else { |
| // In this case the loop operand type was a byte, and there is no need for a |
| // residual loop to copy the remaining memory after the main loop. |
| // We do however need to patch up the control flow by creating the |
| // terminators for the preloop block and the memcpy loop. |
| ConstantInt *Zero = ConstantInt::get(ILengthType, 0U); |
| PLBuilder.CreateCondBr(PLBuilder.CreateICmpNE(RuntimeLoopCount, Zero), |
| LoopBB, PostLoopBB); |
| PreLoopBB->getTerminator()->eraseFromParent(); |
| LoopBuilder.CreateCondBr( |
| LoopBuilder.CreateICmpULT(NewIndex, RuntimeLoopCount), LoopBB, |
| PostLoopBB); |
| } |
| } |
| |
| // Lower memmove to IR. memmove is required to correctly copy overlapping memory |
| // regions; therefore, it has to check the relative positions of the source and |
| // destination pointers and choose the copy direction accordingly. |
| // |
| // The code below is an IR rendition of this C function: |
| // |
| // void* memmove(void* dst, const void* src, size_t n) { |
| // unsigned char* d = dst; |
| // const unsigned char* s = src; |
| // if (s < d) { |
| // // copy backwards |
| // while (n--) { |
| // d[n] = s[n]; |
| // } |
| // } else { |
| // // copy forward |
| // for (size_t i = 0; i < n; ++i) { |
| // d[i] = s[i]; |
| // } |
| // } |
| // return dst; |
| // } |
| static void createMemMoveLoop(Instruction *InsertBefore, Value *SrcAddr, |
| Value *DstAddr, Value *CopyLen, Align SrcAlign, |
| Align DstAlign, bool SrcIsVolatile, |
| bool DstIsVolatile) { |
| Type *TypeOfCopyLen = CopyLen->getType(); |
| BasicBlock *OrigBB = InsertBefore->getParent(); |
| Function *F = OrigBB->getParent(); |
| const DataLayout &DL = F->getParent()->getDataLayout(); |
| |
| // TODO: Use different element type if possible? |
| IRBuilder<> CastBuilder(InsertBefore); |
| Type *EltTy = CastBuilder.getInt8Ty(); |
| Type *PtrTy = |
| CastBuilder.getInt8PtrTy(SrcAddr->getType()->getPointerAddressSpace()); |
| SrcAddr = CastBuilder.CreateBitCast(SrcAddr, PtrTy); |
| DstAddr = CastBuilder.CreateBitCast(DstAddr, PtrTy); |
| |
| // Create the a comparison of src and dst, based on which we jump to either |
| // the forward-copy part of the function (if src >= dst) or the backwards-copy |
| // part (if src < dst). |
| // SplitBlockAndInsertIfThenElse conveniently creates the basic if-then-else |
| // structure. Its block terminators (unconditional branches) are replaced by |
| // the appropriate conditional branches when the loop is built. |
| ICmpInst *PtrCompare = new ICmpInst(InsertBefore, ICmpInst::ICMP_ULT, |
| SrcAddr, DstAddr, "compare_src_dst"); |
| Instruction *ThenTerm, *ElseTerm; |
| SplitBlockAndInsertIfThenElse(PtrCompare, InsertBefore, &ThenTerm, |
| &ElseTerm); |
| |
| // Each part of the function consists of two blocks: |
| // copy_backwards: used to skip the loop when n == 0 |
| // copy_backwards_loop: the actual backwards loop BB |
| // copy_forward: used to skip the loop when n == 0 |
| // copy_forward_loop: the actual forward loop BB |
| BasicBlock *CopyBackwardsBB = ThenTerm->getParent(); |
| CopyBackwardsBB->setName("copy_backwards"); |
| BasicBlock *CopyForwardBB = ElseTerm->getParent(); |
| CopyForwardBB->setName("copy_forward"); |
| BasicBlock *ExitBB = InsertBefore->getParent(); |
| ExitBB->setName("memmove_done"); |
| |
| unsigned PartSize = DL.getTypeStoreSize(EltTy); |
| Align PartSrcAlign(commonAlignment(SrcAlign, PartSize)); |
| Align PartDstAlign(commonAlignment(DstAlign, PartSize)); |
| |
| // Initial comparison of n == 0 that lets us skip the loops altogether. Shared |
| // between both backwards and forward copy clauses. |
| ICmpInst *CompareN = |
| new ICmpInst(OrigBB->getTerminator(), ICmpInst::ICMP_EQ, CopyLen, |
| ConstantInt::get(TypeOfCopyLen, 0), "compare_n_to_0"); |
| |
| // Copying backwards. |
| BasicBlock *LoopBB = |
| BasicBlock::Create(F->getContext(), "copy_backwards_loop", F, CopyForwardBB); |
| IRBuilder<> LoopBuilder(LoopBB); |
| PHINode *LoopPhi = LoopBuilder.CreatePHI(TypeOfCopyLen, 0); |
| Value *IndexPtr = LoopBuilder.CreateSub( |
| LoopPhi, ConstantInt::get(TypeOfCopyLen, 1), "index_ptr"); |
| Value *Element = LoopBuilder.CreateAlignedLoad( |
| EltTy, LoopBuilder.CreateInBoundsGEP(EltTy, SrcAddr, IndexPtr), |
| PartSrcAlign, "element"); |
| LoopBuilder.CreateAlignedStore( |
| Element, LoopBuilder.CreateInBoundsGEP(EltTy, DstAddr, IndexPtr), |
| PartDstAlign); |
| LoopBuilder.CreateCondBr( |
| LoopBuilder.CreateICmpEQ(IndexPtr, ConstantInt::get(TypeOfCopyLen, 0)), |
| ExitBB, LoopBB); |
| LoopPhi->addIncoming(IndexPtr, LoopBB); |
| LoopPhi->addIncoming(CopyLen, CopyBackwardsBB); |
| BranchInst::Create(ExitBB, LoopBB, CompareN, ThenTerm); |
| ThenTerm->eraseFromParent(); |
| |
| // Copying forward. |
| BasicBlock *FwdLoopBB = |
| BasicBlock::Create(F->getContext(), "copy_forward_loop", F, ExitBB); |
| IRBuilder<> FwdLoopBuilder(FwdLoopBB); |
| PHINode *FwdCopyPhi = FwdLoopBuilder.CreatePHI(TypeOfCopyLen, 0, "index_ptr"); |
| Value *SrcGEP = FwdLoopBuilder.CreateInBoundsGEP(EltTy, SrcAddr, FwdCopyPhi); |
| Value *FwdElement = |
| FwdLoopBuilder.CreateAlignedLoad(EltTy, SrcGEP, PartSrcAlign, "element"); |
| Value *DstGEP = FwdLoopBuilder.CreateInBoundsGEP(EltTy, DstAddr, FwdCopyPhi); |
| FwdLoopBuilder.CreateAlignedStore(FwdElement, DstGEP, PartDstAlign); |
| Value *FwdIndexPtr = FwdLoopBuilder.CreateAdd( |
| FwdCopyPhi, ConstantInt::get(TypeOfCopyLen, 1), "index_increment"); |
| FwdLoopBuilder.CreateCondBr(FwdLoopBuilder.CreateICmpEQ(FwdIndexPtr, CopyLen), |
| ExitBB, FwdLoopBB); |
| FwdCopyPhi->addIncoming(FwdIndexPtr, FwdLoopBB); |
| FwdCopyPhi->addIncoming(ConstantInt::get(TypeOfCopyLen, 0), CopyForwardBB); |
| |
| BranchInst::Create(ExitBB, FwdLoopBB, CompareN, ElseTerm); |
| ElseTerm->eraseFromParent(); |
| } |
| |
| static void createMemSetLoop(Instruction *InsertBefore, Value *DstAddr, |
| Value *CopyLen, Value *SetValue, Align DstAlign, |
| bool IsVolatile) { |
| Type *TypeOfCopyLen = CopyLen->getType(); |
| BasicBlock *OrigBB = InsertBefore->getParent(); |
| Function *F = OrigBB->getParent(); |
| const DataLayout &DL = F->getParent()->getDataLayout(); |
| BasicBlock *NewBB = |
| OrigBB->splitBasicBlock(InsertBefore, "split"); |
| BasicBlock *LoopBB |
| = BasicBlock::Create(F->getContext(), "loadstoreloop", F, NewBB); |
| |
| IRBuilder<> Builder(OrigBB->getTerminator()); |
| |
| // Cast pointer to the type of value getting stored |
| unsigned dstAS = cast<PointerType>(DstAddr->getType())->getAddressSpace(); |
| DstAddr = Builder.CreateBitCast(DstAddr, |
| PointerType::get(SetValue->getType(), dstAS)); |
| |
| Builder.CreateCondBr( |
| Builder.CreateICmpEQ(ConstantInt::get(TypeOfCopyLen, 0), CopyLen), NewBB, |
| LoopBB); |
| OrigBB->getTerminator()->eraseFromParent(); |
| |
| unsigned PartSize = DL.getTypeStoreSize(SetValue->getType()); |
| Align PartAlign(commonAlignment(DstAlign, PartSize)); |
| |
| IRBuilder<> LoopBuilder(LoopBB); |
| PHINode *LoopIndex = LoopBuilder.CreatePHI(TypeOfCopyLen, 0); |
| LoopIndex->addIncoming(ConstantInt::get(TypeOfCopyLen, 0), OrigBB); |
| |
| LoopBuilder.CreateAlignedStore( |
| SetValue, |
| LoopBuilder.CreateInBoundsGEP(SetValue->getType(), DstAddr, LoopIndex), |
| PartAlign, IsVolatile); |
| |
| Value *NewIndex = |
| LoopBuilder.CreateAdd(LoopIndex, ConstantInt::get(TypeOfCopyLen, 1)); |
| LoopIndex->addIncoming(NewIndex, LoopBB); |
| |
| LoopBuilder.CreateCondBr(LoopBuilder.CreateICmpULT(NewIndex, CopyLen), LoopBB, |
| NewBB); |
| } |
| |
| template <typename T> |
| static bool canOverlap(MemTransferBase<T> *Memcpy, ScalarEvolution *SE) { |
| if (SE) { |
| auto *SrcSCEV = SE->getSCEV(Memcpy->getRawSource()); |
| auto *DestSCEV = SE->getSCEV(Memcpy->getRawDest()); |
| if (SE->isKnownPredicateAt(CmpInst::ICMP_NE, SrcSCEV, DestSCEV, Memcpy)) |
| return false; |
| } |
| return true; |
| } |
| |
| void llvm::expandMemCpyAsLoop(MemCpyInst *Memcpy, |
| const TargetTransformInfo &TTI, |
| ScalarEvolution *SE) { |
| bool CanOverlap = canOverlap(Memcpy, SE); |
| if (ConstantInt *CI = dyn_cast<ConstantInt>(Memcpy->getLength())) { |
| createMemCpyLoopKnownSize( |
| /* InsertBefore */ Memcpy, |
| /* SrcAddr */ Memcpy->getRawSource(), |
| /* DstAddr */ Memcpy->getRawDest(), |
| /* CopyLen */ CI, |
| /* SrcAlign */ Memcpy->getSourceAlign().valueOrOne(), |
| /* DestAlign */ Memcpy->getDestAlign().valueOrOne(), |
| /* SrcIsVolatile */ Memcpy->isVolatile(), |
| /* DstIsVolatile */ Memcpy->isVolatile(), |
| /* CanOverlap */ CanOverlap, |
| /* TargetTransformInfo */ TTI); |
| } else { |
| createMemCpyLoopUnknownSize( |
| /* InsertBefore */ Memcpy, |
| /* SrcAddr */ Memcpy->getRawSource(), |
| /* DstAddr */ Memcpy->getRawDest(), |
| /* CopyLen */ Memcpy->getLength(), |
| /* SrcAlign */ Memcpy->getSourceAlign().valueOrOne(), |
| /* DestAlign */ Memcpy->getDestAlign().valueOrOne(), |
| /* SrcIsVolatile */ Memcpy->isVolatile(), |
| /* DstIsVolatile */ Memcpy->isVolatile(), |
| /* CanOverlap */ CanOverlap, |
| /* TargetTransformInfo */ TTI); |
| } |
| } |
| |
| void llvm::expandMemMoveAsLoop(MemMoveInst *Memmove) { |
| createMemMoveLoop(/* InsertBefore */ Memmove, |
| /* SrcAddr */ Memmove->getRawSource(), |
| /* DstAddr */ Memmove->getRawDest(), |
| /* CopyLen */ Memmove->getLength(), |
| /* SrcAlign */ Memmove->getSourceAlign().valueOrOne(), |
| /* DestAlign */ Memmove->getDestAlign().valueOrOne(), |
| /* SrcIsVolatile */ Memmove->isVolatile(), |
| /* DstIsVolatile */ Memmove->isVolatile()); |
| } |
| |
| void llvm::expandMemSetAsLoop(MemSetInst *Memset) { |
| createMemSetLoop(/* InsertBefore */ Memset, |
| /* DstAddr */ Memset->getRawDest(), |
| /* CopyLen */ Memset->getLength(), |
| /* SetValue */ Memset->getValue(), |
| /* Alignment */ Memset->getDestAlign().valueOrOne(), |
| Memset->isVolatile()); |
| } |
| |
| void llvm::expandAtomicMemCpyAsLoop(AtomicMemCpyInst *AtomicMemcpy, |
| const TargetTransformInfo &TTI, |
| ScalarEvolution *SE) { |
| if (ConstantInt *CI = dyn_cast<ConstantInt>(AtomicMemcpy->getLength())) { |
| createMemCpyLoopKnownSize( |
| /* InsertBefore */ AtomicMemcpy, |
| /* SrcAddr */ AtomicMemcpy->getRawSource(), |
| /* DstAddr */ AtomicMemcpy->getRawDest(), |
| /* CopyLen */ CI, |
| /* SrcAlign */ AtomicMemcpy->getSourceAlign().valueOrOne(), |
| /* DestAlign */ AtomicMemcpy->getDestAlign().valueOrOne(), |
| /* SrcIsVolatile */ AtomicMemcpy->isVolatile(), |
| /* DstIsVolatile */ AtomicMemcpy->isVolatile(), |
| /* CanOverlap */ false, // SrcAddr & DstAddr may not overlap by spec. |
| /* TargetTransformInfo */ TTI, |
| /* AtomicCpySize */ AtomicMemcpy->getElementSizeInBytes()); |
| } else { |
| createMemCpyLoopUnknownSize( |
| /* InsertBefore */ AtomicMemcpy, |
| /* SrcAddr */ AtomicMemcpy->getRawSource(), |
| /* DstAddr */ AtomicMemcpy->getRawDest(), |
| /* CopyLen */ AtomicMemcpy->getLength(), |
| /* SrcAlign */ AtomicMemcpy->getSourceAlign().valueOrOne(), |
| /* DestAlign */ AtomicMemcpy->getDestAlign().valueOrOne(), |
| /* SrcIsVolatile */ AtomicMemcpy->isVolatile(), |
| /* DstIsVolatile */ AtomicMemcpy->isVolatile(), |
| /* CanOverlap */ false, // SrcAddr & DstAddr may not overlap by spec. |
| /* TargetTransformInfo */ TTI, |
| /* AtomicCpySize */ AtomicMemcpy->getElementSizeInBytes()); |
| } |
| } |
