--- /dev/null
+//===- SROA.cpp - Scalar Replacement Of Aggregates ------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This transformation implements the well known scalar replacement of
+/// aggregates transformation. It tries to identify promotable elements of an
+/// aggregate alloca, and promote them to registers. It will also try to
+/// convert uses of an element (or set of elements) of an alloca into a vector
+/// or bitfield-style integer scalar if appropriate.
+///
+/// It works to do this with minimal slicing of the alloca so that regions
+/// which are merely transferred in and out of external memory remain unchanged
+/// and are not decomposed to scalar code.
+///
+/// Because this also performs alloca promotion, it can be thought of as also
+/// serving the purpose of SSA formation. The algorithm iterates on the
+/// function until all opportunities for promotion have been realized.
+///
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sroa"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Constants.h"
+#include "llvm/DIBuilder.h"
+#include "llvm/DebugInfo.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/IRBuilder.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Module.h"
+#include "llvm/Operator.h"
+#include "llvm/Pass.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/TinyPtrVector.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/Loads.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/GetElementPtrTypeIterator.h"
+#include "llvm/Support/InstVisitor.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/PromoteMemToReg.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
+using namespace llvm;
+
+STATISTIC(NumAllocasAnalyzed, "Number of allocas analyzed for replacement");
+STATISTIC(NumNewAllocas, "Number of new, smaller allocas introduced");
+STATISTIC(NumPromoted, "Number of allocas promoted to SSA values");
+STATISTIC(NumLoadsSpeculated, "Number of loads speculated to allow promotion");
+STATISTIC(NumDeleted, "Number of instructions deleted");
+STATISTIC(NumVectorized, "Number of vectorized aggregates");
+
+namespace {
+/// \brief Alloca partitioning representation.
+///
+/// This class represents a partitioning of an alloca into slices, and
+/// information about the nature of uses of each slice of the alloca. The goal
+/// is that this information is sufficient to decide if and how to split the
+/// alloca apart and replace slices with scalars. It is also intended that this
+/// structure can capture the relevant information needed both due decide about
+/// and to enact these transformations.
+class AllocaPartitioning {
+public:
+ /// \brief A common base class for representing a half-open byte range.
+ struct ByteRange {
+ /// \brief The beginning offset of the range.
+ uint64_t BeginOffset;
+
+ /// \brief The ending offset, not included in the range.
+ uint64_t EndOffset;
+
+ ByteRange() : BeginOffset(), EndOffset() {}
+ ByteRange(uint64_t BeginOffset, uint64_t EndOffset)
+ : BeginOffset(BeginOffset), EndOffset(EndOffset) {}
+
+ /// \brief Support for ordering ranges.
+ ///
+ /// This provides an ordering over ranges such that start offsets are
+ /// always increasing, and within equal start offsets, the end offsets are
+ /// decreasing. Thus the spanning range comes first in in cluster with the
+ /// same start position.
+ bool operator<(const ByteRange &RHS) const {
+ if (BeginOffset < RHS.BeginOffset) return true;
+ if (BeginOffset > RHS.BeginOffset) return false;
+ if (EndOffset > RHS.EndOffset) return true;
+ return false;
+ }
+
+ /// \brief Support comparison with a single offset to allow binary searches.
+ bool operator<(uint64_t RHSOffset) const {
+ return BeginOffset < RHSOffset;
+ }
+
+ bool operator==(const ByteRange &RHS) const {
+ return BeginOffset == RHS.BeginOffset && EndOffset == RHS.EndOffset;
+ }
+ bool operator!=(const ByteRange &RHS) const { return !operator==(RHS); }
+ };
+
+ /// \brief A partition of an alloca.
+ ///
+ /// This structure represents a contiguous partition of the alloca. These are
+ /// formed by examining the uses of the alloca. During formation, they may
+ /// overlap but once an AllocaPartitioning is built, the Partitions within it
+ /// are all disjoint.
+ struct Partition : public ByteRange {
+ /// \brief Whether this partition is splittable into smaller partitions.
+ ///
+ /// We flag partitions as splittable when they are formed entirely due to
+ /// accesses by trivially split operations such as memset and memcpy.
+ ///
+ /// FIXME: At some point we should consider loads and stores of FCAs to be
+ /// splittable and eagerly split them into scalar values.
+ bool IsSplittable;
+
+ Partition() : ByteRange(), IsSplittable() {}
+ Partition(uint64_t BeginOffset, uint64_t EndOffset, bool IsSplittable)
+ : ByteRange(BeginOffset, EndOffset), IsSplittable(IsSplittable) {}
+ };
+
+ /// \brief A particular use of a partition of the alloca.
+ ///
+ /// This structure is used to associate uses of a partition with it. They
+ /// mark the range of bytes which are referenced by a particular instruction,
+ /// and includes a handle to the user itself and the pointer value in use.
+ /// The bounds of these uses are determined by intersecting the bounds of the
+ /// memory use itself with a particular partition. As a consequence there is
+ /// intentionally overlap between various usues of the same partition.
+ struct PartitionUse : public ByteRange {
+ /// \brief The user of this range of the alloca.
+ AssertingVH<Instruction> User;
+
+ /// \brief The particular pointer value derived from this alloca in use.
+ AssertingVH<Instruction> Ptr;
+
+ PartitionUse() : ByteRange(), User(), Ptr() {}
+ PartitionUse(uint64_t BeginOffset, uint64_t EndOffset,
+ Instruction *User, Instruction *Ptr)
+ : ByteRange(BeginOffset, EndOffset), User(User), Ptr(Ptr) {}
+ };
+
+ /// \brief Construct a partitioning of a particular alloca.
+ ///
+ /// Construction does most of the work for partitioning the alloca. This
+ /// performs the necessary walks of users and builds a partitioning from it.
+ AllocaPartitioning(const TargetData &TD, AllocaInst &AI);
+
+ /// \brief Test whether a pointer to the allocation escapes our analysis.
+ ///
+ /// If this is true, the partitioning is never fully built and should be
+ /// ignored.
+ bool isEscaped() const { return PointerEscapingInstr; }
+
+ /// \brief Support for iterating over the partitions.
+ /// @{
+ typedef SmallVectorImpl<Partition>::iterator iterator;
+ iterator begin() { return Partitions.begin(); }
+ iterator end() { return Partitions.end(); }
+
+ typedef SmallVectorImpl<Partition>::const_iterator const_iterator;
+ const_iterator begin() const { return Partitions.begin(); }
+ const_iterator end() const { return Partitions.end(); }
+ /// @}
+
+ /// \brief Support for iterating over and manipulating a particular
+ /// partition's uses.
+ ///
+ /// The iteration support provided for uses is more limited, but also
+ /// includes some manipulation routines to support rewriting the uses of
+ /// partitions during SROA.
+ /// @{
+ typedef SmallVectorImpl<PartitionUse>::iterator use_iterator;
+ use_iterator use_begin(unsigned Idx) { return Uses[Idx].begin(); }
+ use_iterator use_begin(const_iterator I) { return Uses[I - begin()].begin(); }
+ use_iterator use_end(unsigned Idx) { return Uses[Idx].end(); }
+ use_iterator use_end(const_iterator I) { return Uses[I - begin()].end(); }
+ void use_insert(unsigned Idx, use_iterator UI, const PartitionUse &U) {
+ Uses[Idx].insert(UI, U);
+ }
+ void use_insert(const_iterator I, use_iterator UI, const PartitionUse &U) {
+ Uses[I - begin()].insert(UI, U);
+ }
+ void use_erase(unsigned Idx, use_iterator UI) { Uses[Idx].erase(UI); }
+ void use_erase(const_iterator I, use_iterator UI) {
+ Uses[I - begin()].erase(UI);
+ }
+
+ typedef SmallVectorImpl<PartitionUse>::const_iterator const_use_iterator;
+ const_use_iterator use_begin(unsigned Idx) const { return Uses[Idx].begin(); }
+ const_use_iterator use_begin(const_iterator I) const {
+ return Uses[I - begin()].begin();
+ }
+ const_use_iterator use_end(unsigned Idx) const { return Uses[Idx].end(); }
+ const_use_iterator use_end(const_iterator I) const {
+ return Uses[I - begin()].end();
+ }
+ /// @}
+
+ /// \brief Allow iterating the dead users for this alloca.
+ ///
+ /// These are instructions which will never actually use the alloca as they
+ /// are outside the allocated range. They are safe to replace with undef and
+ /// delete.
+ /// @{
+ typedef SmallVectorImpl<Instruction *>::const_iterator dead_user_iterator;
+ dead_user_iterator dead_user_begin() const { return DeadUsers.begin(); }
+ dead_user_iterator dead_user_end() const { return DeadUsers.end(); }
+ /// @}
+
+ /// \brief Allow iterating the dead operands referring to this alloca.
+ ///
+ /// These are operands which have cannot actually be used to refer to the
+ /// alloca as they are outside its range and the user doesn't correct for
+ /// that. These mostly consist of PHI node inputs and the like which we just
+ /// need to replace with undef.
+ /// @{
+ typedef SmallVectorImpl<Use *>::const_iterator dead_op_iterator;
+ dead_op_iterator dead_op_begin() const { return DeadOperands.begin(); }
+ dead_op_iterator dead_op_end() const { return DeadOperands.end(); }
+ /// @}
+
+ /// \brief MemTransferInst auxiliary data.
+ /// This struct provides some auxiliary data about memory transfer
+ /// intrinsics such as memcpy and memmove. These intrinsics can use two
+ /// different ranges within the same alloca, and provide other challenges to
+ /// correctly represent. We stash extra data to help us untangle this
+ /// after the partitioning is complete.
+ struct MemTransferOffsets {
+ uint64_t DestBegin, DestEnd;
+ uint64_t SourceBegin, SourceEnd;
+ bool IsSplittable;
+ };
+ MemTransferOffsets getMemTransferOffsets(MemTransferInst &II) const {
+ return MemTransferInstData.lookup(&II);
+ }
+
+ /// \brief Map from a PHI or select operand back to a partition.
+ ///
+ /// When manipulating PHI nodes or selects, they can use more than one
+ /// partition of an alloca. We store a special mapping to allow finding the
+ /// partition referenced by each of these operands, if any.
+ iterator findPartitionForPHIOrSelectOperand(Instruction &I, Value *Op) {
+ SmallDenseMap<std::pair<Instruction *, Value *>,
+ std::pair<unsigned, unsigned> >::const_iterator MapIt
+ = PHIOrSelectOpMap.find(std::make_pair(&I, Op));
+ if (MapIt == PHIOrSelectOpMap.end())
+ return end();
+
+ return begin() + MapIt->second.first;
+ }
+
+ /// \brief Map from a PHI or select operand back to the specific use of
+ /// a partition.
+ ///
+ /// Similar to mapping these operands back to the partitions, this maps
+ /// directly to the use structure of that partition.
+ use_iterator findPartitionUseForPHIOrSelectOperand(Instruction &I,
+ Value *Op) {
+ SmallDenseMap<std::pair<Instruction *, Value *>,
+ std::pair<unsigned, unsigned> >::const_iterator MapIt
+ = PHIOrSelectOpMap.find(std::make_pair(&I, Op));
+ assert(MapIt != PHIOrSelectOpMap.end());
+ return Uses[MapIt->second.first].begin() + MapIt->second.second;
+ }
+
+ /// \brief Compute a common type among the uses of a particular partition.
+ ///
+ /// This routines walks all of the uses of a particular partition and tries
+ /// to find a common type between them. Untyped operations such as memset and
+ /// memcpy are ignored.
+ Type *getCommonType(iterator I) const;
+
+ void print(raw_ostream &OS, const_iterator I, StringRef Indent = " ") const;
+ void printUsers(raw_ostream &OS, const_iterator I,
+ StringRef Indent = " ") const;
+ void print(raw_ostream &OS) const;
+ void dump(const_iterator I) const LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED;
+ void dump() const LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED;
+
+private:
+ template <typename DerivedT, typename RetT = void> class BuilderBase;
+ class PartitionBuilder;
+ friend class AllocaPartitioning::PartitionBuilder;
+ class UseBuilder;
+ friend class AllocaPartitioning::UseBuilder;
+
+ /// \brief Handle to alloca instruction to simplify method interfaces.
+ AllocaInst &AI;
+
+ /// \brief The instruction responsible for this alloca having no partitioning.
+ ///
+ /// When an instruction (potentially) escapes the pointer to the alloca, we
+ /// store a pointer to that here and abort trying to partition the alloca.
+ /// This will be null if the alloca is partitioned successfully.
+ Instruction *PointerEscapingInstr;
+
+ /// \brief The partitions of the alloca.
+ ///
+ /// We store a vector of the partitions over the alloca here. This vector is
+ /// sorted by increasing begin offset, and then by decreasing end offset. See
+ /// the Partition inner class for more details. Initially there are overlaps,
+ /// be during construction we form a disjoint sequence toward the end.
+ SmallVector<Partition, 8> Partitions;
+
+ /// \brief The uses of the partitions.
+ ///
+ /// This is essentially a mapping from each partition to a list of uses of
+ /// that partition. The mapping is done with a Uses vector that has the exact
+ /// same number of entries as the partition vector. Each entry is itself
+ /// a vector of the uses.
+ SmallVector<SmallVector<PartitionUse, 2>, 8> Uses;
+
+ /// \brief Instructions which will become dead if we rewrite the alloca.
+ ///
+ /// Note that these are not separated by partition. This is because we expect
+ /// a partitioned alloca to be completely rewritten or not rewritten at all.
+ /// If rewritten, all these instructions can simply be removed and replaced
+ /// with undef as they come from outside of the allocated space.
+ SmallVector<Instruction *, 8> DeadUsers;
+
+ /// \brief Operands which will become dead if we rewrite the alloca.
+ ///
+ /// These are operands that in their particular use can be replaced with
+ /// undef when we rewrite the alloca. These show up in out-of-bounds inputs
+ /// to PHI nodes and the like. They aren't entirely dead (there might be
+ /// a GEP back into the bounds using it elsewhere) and nor is the PHI, but we
+ /// want to swap this particular input for undef to simplify the use lists of
+ /// the alloca.
+ SmallVector<Use *, 8> DeadOperands;
+
+ /// \brief The underlying storage for auxiliary memcpy and memset info.
+ SmallDenseMap<MemTransferInst *, MemTransferOffsets, 4> MemTransferInstData;
+
+ /// \brief A side datastructure used when building up the partitions and uses.
+ ///
+ /// This mapping is only really used during the initial building of the
+ /// partitioning so that we can retain information about PHI and select nodes
+ /// processed.
+ SmallDenseMap<Instruction *, std::pair<uint64_t, bool> > PHIOrSelectSizes;
+
+ /// \brief Auxiliary information for particular PHI or select operands.
+ SmallDenseMap<std::pair<Instruction *, Value *>,
+ std::pair<unsigned, unsigned>, 4> PHIOrSelectOpMap;
+
+ /// \brief A utility routine called from the constructor.
+ ///
+ /// This does what it says on the tin. It is the key of the alloca partition
+ /// splitting and merging. After it is called we have the desired disjoint
+ /// collection of partitions.
+ void splitAndMergePartitions();
+};
+}
+
+template <typename DerivedT, typename RetT>
+class AllocaPartitioning::BuilderBase
+ : public InstVisitor<DerivedT, RetT> {
+public:
+ BuilderBase(const TargetData &TD, AllocaInst &AI, AllocaPartitioning &P)
+ : TD(TD),
+ AllocSize(TD.getTypeAllocSize(AI.getAllocatedType())),
+ P(P) {
+ enqueueUsers(AI, 0);
+ }
+
+protected:
+ const TargetData &TD;
+ const uint64_t AllocSize;
+ AllocaPartitioning &P;
+
+ struct OffsetUse {
+ Use *U;
+ uint64_t Offset;
+ };
+ SmallVector<OffsetUse, 8> Queue;
+
+ // The active offset and use while visiting.
+ Use *U;
+ uint64_t Offset;
+
+ void enqueueUsers(Instruction &I, uint64_t UserOffset) {
+ SmallPtrSet<User *, 8> UserSet;
+ for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
+ UI != UE; ++UI) {
+ if (!UserSet.insert(*UI))
+ continue;
+
+ OffsetUse OU = { &UI.getUse(), UserOffset };
+ Queue.push_back(OU);
+ }
+ }
+
+ bool computeConstantGEPOffset(GetElementPtrInst &GEPI, uint64_t &GEPOffset) {
+ GEPOffset = Offset;
+ for (gep_type_iterator GTI = gep_type_begin(GEPI), GTE = gep_type_end(GEPI);
+ GTI != GTE; ++GTI) {
+ ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
+ if (!OpC)
+ return false;
+ if (OpC->isZero())
+ continue;
+
+ // Handle a struct index, which adds its field offset to the pointer.
+ if (StructType *STy = dyn_cast<StructType>(*GTI)) {
+ unsigned ElementIdx = OpC->getZExtValue();
+ const StructLayout *SL = TD.getStructLayout(STy);
+ GEPOffset += SL->getElementOffset(ElementIdx);
+ continue;
+ }
+
+ GEPOffset
+ += OpC->getZExtValue() * TD.getTypeAllocSize(GTI.getIndexedType());
+ }
+ return true;
+ }
+
+ Value *foldSelectInst(SelectInst &SI) {
+ // If the condition being selected on is a constant or the same value is
+ // being selected between, fold the select. Yes this does (rarely) happen
+ // early on.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(SI.getCondition()))
+ return SI.getOperand(1+CI->isZero());
+ if (SI.getOperand(1) == SI.getOperand(2)) {
+ assert(*U == SI.getOperand(1));
+ return SI.getOperand(1);
+ }
+ return 0;
+ }
+};
+
+/// \brief Builder for the alloca partitioning.
+///
+/// This class builds an alloca partitioning by recursively visiting the uses
+/// of an alloca and splitting the partitions for each load and store at each
+/// offset.
+class AllocaPartitioning::PartitionBuilder
+ : public BuilderBase<PartitionBuilder, bool> {
+ friend class InstVisitor<PartitionBuilder, bool>;
+
+ SmallDenseMap<Instruction *, unsigned> MemTransferPartitionMap;
+
+public:
+ PartitionBuilder(const TargetData &TD, AllocaInst &AI, AllocaPartitioning &P)
+ : BuilderBase(TD, AI, P) {}
+
+ /// \brief Run the builder over the allocation.
+ bool operator()() {
+ // Note that we have to re-evaluate size on each trip through the loop as
+ // the queue grows at the tail.
+ for (unsigned Idx = 0; Idx < Queue.size(); ++Idx) {
+ U = Queue[Idx].U;
+ Offset = Queue[Idx].Offset;
+ if (!visit(cast<Instruction>(U->getUser())))
+ return false;
+ }
+ return true;
+ }
+
+private:
+ bool markAsEscaping(Instruction &I) {
+ P.PointerEscapingInstr = &I;
+ return false;
+ }
+
+ void insertUse(Instruction &I, uint64_t Size, bool IsSplittable = false) {
+ uint64_t BeginOffset = Offset, EndOffset = Offset + Size;
+
+ // Completely skip uses which start outside of the allocation.
+ if (BeginOffset >= AllocSize) {
+ DEBUG(dbgs() << "WARNING: Ignoring " << Size << " byte use @" << Offset
+ << " which starts past the end of the " << AllocSize
+ << " byte alloca:\n"
+ << " alloca: " << P.AI << "\n"
+ << " use: " << I << "\n");
+ return;
+ }
+
+ // Clamp the size to the allocation.
+ if (EndOffset > AllocSize) {
+ DEBUG(dbgs() << "WARNING: Clamping a " << Size << " byte use @" << Offset
+ << " to remain within the " << AllocSize << " byte alloca:\n"
+ << " alloca: " << P.AI << "\n"
+ << " use: " << I << "\n");
+ EndOffset = AllocSize;
+ }
+
+ // See if we can just add a user onto the last slot currently occupied.
+ if (!P.Partitions.empty() &&
+ P.Partitions.back().BeginOffset == BeginOffset &&
+ P.Partitions.back().EndOffset == EndOffset) {
+ P.Partitions.back().IsSplittable &= IsSplittable;
+ return;
+ }
+
+ Partition New(BeginOffset, EndOffset, IsSplittable);
+ P.Partitions.push_back(New);
+ }
+
+ bool handleLoadOrStore(Type *Ty, Instruction &I) {
+ uint64_t Size = TD.getTypeStoreSize(Ty);
+
+ // If this memory access can be shown to *statically* extend outside the
+ // bounds of of the allocation, it's behavior is undefined, so simply
+ // ignore it. Note that this is more strict than the generic clamping
+ // behavior of insertUse. We also try to handle cases which might run the
+ // risk of overflow.
+ // FIXME: We should instead consider the pointer to have escaped if this
+ // function is being instrumented for addressing bugs or race conditions.
+ if (Offset >= AllocSize || Size > AllocSize || Offset + Size > AllocSize) {
+ DEBUG(dbgs() << "WARNING: Ignoring " << Size << " byte "
+ << (isa<LoadInst>(I) ? "load" : "store") << " @" << Offset
+ << " which extends past the end of the " << AllocSize
+ << " byte alloca:\n"
+ << " alloca: " << P.AI << "\n"
+ << " use: " << I << "\n");
+ return true;
+ }
+
+ insertUse(I, Size);
+ return true;
+ }
+
+ bool visitBitCastInst(BitCastInst &BC) {
+ enqueueUsers(BC, Offset);
+ return true;
+ }
+
+ bool visitGetElementPtrInst(GetElementPtrInst &GEPI) {
+ //unsigned IntPtrWidth = TD->getPointerSizeInBits();
+ //assert(IntPtrWidth == Offset.getBitWidth());
+ uint64_t GEPOffset;
+ if (!computeConstantGEPOffset(GEPI, GEPOffset))
+ return markAsEscaping(GEPI);
+
+ enqueueUsers(GEPI, GEPOffset);
+ return true;
+ }
+
+ bool visitLoadInst(LoadInst &LI) {
+ return handleLoadOrStore(LI.getType(), LI);
+ }
+
+ bool visitStoreInst(StoreInst &SI) {
+ if (SI.getOperand(0) == *U)
+ return markAsEscaping(SI);
+
+ return handleLoadOrStore(SI.getOperand(0)->getType(), SI);
+ }
+
+
+ bool visitMemSetInst(MemSetInst &II) {
+ ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
+ insertUse(II, Length ? Length->getZExtValue() : AllocSize - Offset, Length);
+ return true;
+ }
+
+ bool visitMemTransferInst(MemTransferInst &II) {
+ ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
+ uint64_t Size = Length ? Length->getZExtValue() : AllocSize - Offset;
+ if (!Size)
+ // Zero-length mem transfer intrinsics can be ignored entirely.
+ return true;
+
+ MemTransferOffsets &Offsets = P.MemTransferInstData[&II];
+
+ // Only intrinsics with a constant length can be split.
+ Offsets.IsSplittable = Length;
+
+ if (*U != II.getRawDest()) {
+ assert(*U == II.getRawSource());
+ Offsets.SourceBegin = Offset;
+ Offsets.SourceEnd = Offset + Size;
+ } else {
+ Offsets.DestBegin = Offset;
+ Offsets.DestEnd = Offset + Size;
+ }
+
+ insertUse(II, Size, Offsets.IsSplittable);
+ unsigned NewIdx = P.Partitions.size() - 1;
+
+ SmallDenseMap<Instruction *, unsigned>::const_iterator PMI;
+ bool Inserted = false;
+ llvm::tie(PMI, Inserted)
+ = MemTransferPartitionMap.insert(std::make_pair(&II, NewIdx));
+ if (!Inserted && Offsets.IsSplittable) {
+ // We've found a memory transfer intrinsic which refers to the alloca as
+ // both a source and dest. We refuse to split these to simplify splitting
+ // logic. If possible, SROA will still split them into separate allocas
+ // and then re-analyze.
+ Offsets.IsSplittable = false;
+ P.Partitions[PMI->second].IsSplittable = false;
+ P.Partitions[NewIdx].IsSplittable = false;
+ }
+
+ return true;
+ }
+
+ // Disable SRoA for any intrinsics except for lifetime invariants.
+ bool visitIntrinsicInst(IntrinsicInst &II) {
+ if (II.getIntrinsicID() == Intrinsic::lifetime_start ||
+ II.getIntrinsicID() == Intrinsic::lifetime_end) {
+ ConstantInt *Length = cast<ConstantInt>(II.getArgOperand(0));
+ uint64_t Size = std::min(AllocSize - Offset, Length->getLimitedValue());
+ insertUse(II, Size, true);
+ return true;
+ }
+
+ return markAsEscaping(II);
+ }
+
+ Instruction *hasUnsafePHIOrSelectUse(Instruction *Root, uint64_t &Size) {
+ // We consider any PHI or select that results in a direct load or store of
+ // the same offset to be a viable use for partitioning purposes. These uses
+ // are considered unsplittable and the size is the maximum loaded or stored
+ // size.
+ SmallPtrSet<Instruction *, 4> Visited;
+ SmallVector<std::pair<Instruction *, Instruction *>, 4> Uses;
+ Visited.insert(Root);
+ Uses.push_back(std::make_pair(cast<Instruction>(*U), Root));
+ do {
+ Instruction *I, *UsedI;
+ llvm::tie(UsedI, I) = Uses.pop_back_val();
+
+ if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+ Size = std::max(Size, TD.getTypeStoreSize(LI->getType()));
+ continue;
+ }
+ if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
+ Value *Op = SI->getOperand(0);
+ if (Op == UsedI)
+ return SI;
+ Size = std::max(Size, TD.getTypeStoreSize(Op->getType()));
+ continue;
+ }
+
+ if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
+ if (!GEP->hasAllZeroIndices())
+ return GEP;
+ } else if (!isa<BitCastInst>(I) && !isa<PHINode>(I) &&
+ !isa<SelectInst>(I)) {
+ return I;
+ }
+
+ for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
+ ++UI)
+ if (Visited.insert(cast<Instruction>(*UI)))
+ Uses.push_back(std::make_pair(I, cast<Instruction>(*UI)));
+ } while (!Uses.empty());
+
+ return 0;
+ }
+
+ bool visitPHINode(PHINode &PN) {
+ // See if we already have computed info on this node.
+ std::pair<uint64_t, bool> &PHIInfo = P.PHIOrSelectSizes[&PN];
+ if (PHIInfo.first) {
+ PHIInfo.second = true;
+ insertUse(PN, PHIInfo.first);
+ return true;
+ }
+
+ // Check for an unsafe use of the PHI node.
+ if (Instruction *EscapingI = hasUnsafePHIOrSelectUse(&PN, PHIInfo.first))
+ return markAsEscaping(*EscapingI);
+
+ insertUse(PN, PHIInfo.first);
+ return true;
+ }
+
+ bool visitSelectInst(SelectInst &SI) {
+ if (Value *Result = foldSelectInst(SI)) {
+ if (Result == *U)
+ // If the result of the constant fold will be the pointer, recurse
+ // through the select as if we had RAUW'ed it.
+ enqueueUsers(SI, Offset);
+
+ return true;
+ }
+
+ // See if we already have computed info on this node.
+ std::pair<uint64_t, bool> &SelectInfo = P.PHIOrSelectSizes[&SI];
+ if (SelectInfo.first) {
+ SelectInfo.second = true;
+ insertUse(SI, SelectInfo.first);
+ return true;
+ }
+
+ // Check for an unsafe use of the PHI node.
+ if (Instruction *EscapingI = hasUnsafePHIOrSelectUse(&SI, SelectInfo.first))
+ return markAsEscaping(*EscapingI);
+
+ insertUse(SI, SelectInfo.first);
+ return true;
+ }
+
+ /// \brief Disable SROA entirely if there are unhandled users of the alloca.
+ bool visitInstruction(Instruction &I) { return markAsEscaping(I); }
+};
+
+
+/// \brief Use adder for the alloca partitioning.
+///
+/// This class adds the uses of an alloca to all of the partitions which it
+/// uses. For splittable partitions, this can end up doing essentially a linear
+/// walk of the partitions, but the number of steps remains bounded by the
+/// total result instruction size:
+/// - The number of partitions is a result of the number unsplittable
+/// instructions using the alloca.
+/// - The number of users of each partition is at worst the total number of
+/// splittable instructions using the alloca.
+/// Thus we will produce N * M instructions in the end, where N are the number
+/// of unsplittable uses and M are the number of splittable. This visitor does
+/// the exact same number of updates to the partitioning.
+///
+/// In the more common case, this visitor will leverage the fact that the
+/// partition space is pre-sorted, and do a logarithmic search for the
+/// partition needed, making the total visit a classical ((N + M) * log(N))
+/// complexity operation.
+class AllocaPartitioning::UseBuilder : public BuilderBase<UseBuilder> {
+ friend class InstVisitor<UseBuilder>;
+
+ /// \brief Set to de-duplicate dead instructions found in the use walk.
+ SmallPtrSet<Instruction *, 4> VisitedDeadInsts;
+
+public:
+ UseBuilder(const TargetData &TD, AllocaInst &AI, AllocaPartitioning &P)
+ : BuilderBase(TD, AI, P) {}
+
+ /// \brief Run the builder over the allocation.
+ void operator()() {
+ // Note that we have to re-evaluate size on each trip through the loop as
+ // the queue grows at the tail.
+ for (unsigned Idx = 0; Idx < Queue.size(); ++Idx) {
+ U = Queue[Idx].U;
+ Offset = Queue[Idx].Offset;
+ this->visit(cast<Instruction>(U->getUser()));
+ }
+ }
+
+private:
+ void markAsDead(Instruction &I) {
+ if (VisitedDeadInsts.insert(&I))
+ P.DeadUsers.push_back(&I);
+ }
+
+ void insertUse(uint64_t Size, Instruction &User) {
+ uint64_t BeginOffset = Offset, EndOffset = Offset + Size;
+
+ // If the use extends outside of the allocation, record it as a dead use
+ // for elimination later.
+ if (BeginOffset >= AllocSize || Size == 0)
+ return markAsDead(User);
+
+ // Bound the use by the size of the allocation.
+ if (EndOffset > AllocSize)
+ EndOffset = AllocSize;
+
+ // NB: This only works if we have zero overlapping partitions.
+ iterator B = std::lower_bound(P.begin(), P.end(), BeginOffset);
+ if (B != P.begin() && llvm::prior(B)->EndOffset > BeginOffset)
+ B = llvm::prior(B);
+ for (iterator I = B, E = P.end(); I != E && I->BeginOffset < EndOffset;
+ ++I) {
+ PartitionUse NewUse(std::max(I->BeginOffset, BeginOffset),
+ std::min(I->EndOffset, EndOffset),
+ &User, cast<Instruction>(*U));
+ P.Uses[I - P.begin()].push_back(NewUse);
+ if (isa<PHINode>(U->getUser()) || isa<SelectInst>(U->getUser()))
+ P.PHIOrSelectOpMap[std::make_pair(&User, U->get())]
+ = std::make_pair(I - P.begin(), P.Uses[I - P.begin()].size() - 1);
+ }
+ }
+
+ void handleLoadOrStore(Type *Ty, Instruction &I) {
+ uint64_t Size = TD.getTypeStoreSize(Ty);
+
+ // If this memory access can be shown to *statically* extend outside the
+ // bounds of of the allocation, it's behavior is undefined, so simply
+ // ignore it. Note that this is more strict than the generic clamping
+ // behavior of insertUse.
+ if (Offset >= AllocSize || Size > AllocSize || Offset + Size > AllocSize)
+ return markAsDead(I);
+
+ insertUse(Size, I);
+ }
+
+ void visitBitCastInst(BitCastInst &BC) {
+ if (BC.use_empty())
+ return markAsDead(BC);
+
+ enqueueUsers(BC, Offset);
+ }
+
+ void visitGetElementPtrInst(GetElementPtrInst &GEPI) {
+ if (GEPI.use_empty())
+ return markAsDead(GEPI);
+
+ //unsigned IntPtrWidth = TD->getPointerSizeInBits();
+ //assert(IntPtrWidth == Offset.getBitWidth());
+ uint64_t GEPOffset;
+ if (!computeConstantGEPOffset(GEPI, GEPOffset))
+ llvm_unreachable("Unable to compute constant offset for use");
+
+ enqueueUsers(GEPI, GEPOffset);
+ }
+
+ void visitLoadInst(LoadInst &LI) {
+ handleLoadOrStore(LI.getType(), LI);
+ }
+
+ void visitStoreInst(StoreInst &SI) {
+ handleLoadOrStore(SI.getOperand(0)->getType(), SI);
+ }
+
+ void visitMemSetInst(MemSetInst &II) {
+ ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
+ insertUse(Length ? Length->getZExtValue() : AllocSize - Offset, II);
+ }
+
+ void visitMemTransferInst(MemTransferInst &II) {
+ ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
+ insertUse(Length ? Length->getZExtValue() : AllocSize - Offset, II);
+ }
+
+ void visitIntrinsicInst(IntrinsicInst &II) {
+ assert(II.getIntrinsicID() == Intrinsic::lifetime_start ||
+ II.getIntrinsicID() == Intrinsic::lifetime_end);
+
+ ConstantInt *Length = cast<ConstantInt>(II.getArgOperand(0));
+ insertUse(std::min(AllocSize - Offset, Length->getLimitedValue()), II);
+ }
+
+ void insertPHIOrSelect(Instruction &User) {
+ uint64_t Size = P.PHIOrSelectSizes.lookup(&User).first;
+
+ // For PHI and select operands outside the alloca, we can't nuke the entire
+ // phi or select -- the other side might still be relevant, so we special
+ // case them here and use a separate structure to track the operands
+ // themselves which should be replaced with undef.
+ if (Offset >= AllocSize) {
+ P.DeadOperands.push_back(U);
+ return;
+ }
+
+ insertUse(Size, User);
+ }
+ void visitPHINode(PHINode &PN) {
+ if (PN.use_empty())
+ return markAsDead(PN);
+
+ insertPHIOrSelect(PN);
+ }
+ void visitSelectInst(SelectInst &SI) {
+ if (SI.use_empty())
+ return markAsDead(SI);
+
+ if (Value *Result = foldSelectInst(SI)) {
+ if (Result == *U)
+ // If the result of the constant fold will be the pointer, recurse
+ // through the select as if we had RAUW'ed it.
+ enqueueUsers(SI, Offset);
+
+ return;
+ }
+
+ insertPHIOrSelect(SI);
+ }
+
+ /// \brief Unreachable, we've already visited the alloca once.
+ void visitInstruction(Instruction &I) {
+ llvm_unreachable("Unhandled instruction in use builder.");
+ }
+};
+
+void AllocaPartitioning::splitAndMergePartitions() {
+ size_t NumDeadPartitions = 0;
+
+ // Track the range of splittable partitions that we pass when accumulating
+ // overlapping unsplittable partitions.
+ uint64_t SplitEndOffset = 0ull;
+
+ Partition New(0ull, 0ull, false);
+
+ for (unsigned i = 0, j = i, e = Partitions.size(); i != e; i = j) {
+ ++j;
+
+ if (!Partitions[i].IsSplittable || New.BeginOffset == New.EndOffset) {
+ assert(New.BeginOffset == New.EndOffset);
+ New = Partitions[i];
+ } else {
+ assert(New.IsSplittable);
+ New.EndOffset = std::max(New.EndOffset, Partitions[i].EndOffset);
+ }
+ assert(New.BeginOffset != New.EndOffset);
+
+ // Scan the overlapping partitions.
+ while (j != e && New.EndOffset > Partitions[j].BeginOffset) {
+ // If the new partition we are forming is splittable, stop at the first
+ // unsplittable partition.
+ if (New.IsSplittable && !Partitions[j].IsSplittable)
+ break;
+
+ // Grow the new partition to include any equally splittable range. 'j' is
+ // always equally splittable when New is splittable, but when New is not
+ // splittable, we may subsume some (or part of some) splitable partition
+ // without growing the new one.
+ if (New.IsSplittable == Partitions[j].IsSplittable) {
+ New.EndOffset = std::max(New.EndOffset, Partitions[j].EndOffset);
+ } else {
+ assert(!New.IsSplittable);
+ assert(Partitions[j].IsSplittable);
+ SplitEndOffset = std::max(SplitEndOffset, Partitions[j].EndOffset);
+ }
+
+ Partitions[j].BeginOffset = Partitions[j].EndOffset = UINT64_MAX;
+ ++NumDeadPartitions;
+ ++j;
+ }
+
+ // If the new partition is splittable, chop off the end as soon as the
+ // unsplittable subsequent partition starts and ensure we eventually cover
+ // the splittable area.
+ if (j != e && New.IsSplittable) {
+ SplitEndOffset = std::max(SplitEndOffset, New.EndOffset);
+ New.EndOffset = std::min(New.EndOffset, Partitions[j].BeginOffset);
+ }
+
+ // Add the new partition if it differs from the original one and is
+ // non-empty. We can end up with an empty partition here if it was
+ // splittable but there is an unsplittable one that starts at the same
+ // offset.
+ if (New != Partitions[i]) {
+ if (New.BeginOffset != New.EndOffset)
+ Partitions.push_back(New);
+ // Mark the old one for removal.
+ Partitions[i].BeginOffset = Partitions[i].EndOffset = UINT64_MAX;
+ ++NumDeadPartitions;
+ }
+
+ New.BeginOffset = New.EndOffset;
+ if (!New.IsSplittable) {
+ New.EndOffset = std::max(New.EndOffset, SplitEndOffset);
+ if (j != e && !Partitions[j].IsSplittable)
+ New.EndOffset = std::min(New.EndOffset, Partitions[j].BeginOffset);
+ New.IsSplittable = true;
+ // If there is a trailing splittable partition which won't be fused into
+ // the next splittable partition go ahead and add it onto the partitions
+ // list.
+ if (New.BeginOffset < New.EndOffset &&
+ (j == e || !Partitions[j].IsSplittable ||
+ New.EndOffset < Partitions[j].BeginOffset)) {
+ Partitions.push_back(New);
+ New.BeginOffset = New.EndOffset = 0ull;
+ }
+ }
+ }
+
+ // Re-sort the partitions now that they have been split and merged into
+ // disjoint set of partitions. Also remove any of the dead partitions we've
+ // replaced in the process.
+ std::sort(Partitions.begin(), Partitions.end());
+ if (NumDeadPartitions) {
+ assert(Partitions.back().BeginOffset == UINT64_MAX);
+ assert(Partitions.back().EndOffset == UINT64_MAX);
+ assert((ptrdiff_t)NumDeadPartitions ==
+ std::count(Partitions.begin(), Partitions.end(), Partitions.back()));
+ }
+ Partitions.erase(Partitions.end() - NumDeadPartitions, Partitions.end());
+}
+
+AllocaPartitioning::AllocaPartitioning(const TargetData &TD, AllocaInst &AI)
+ : AI(AI), PointerEscapingInstr(0) {
+ PartitionBuilder PB(TD, AI, *this);
+ if (!PB())
+ return;
+
+ if (Partitions.size() > 1) {
+ // Sort the uses. This arranges for the offsets to be in ascending order,
+ // and the sizes to be in descending order.
+ std::sort(Partitions.begin(), Partitions.end());
+
+ // Intersect splittability for all partitions with equal offsets and sizes.
+ // Then remove all but the first so that we have a sequence of non-equal but
+ // potentially overlapping partitions.
+ for (iterator I = Partitions.begin(), J = I, E = Partitions.end(); I != E;
+ I = J) {
+ ++J;
+ while (J != E && *I == *J) {
+ I->IsSplittable &= J->IsSplittable;
+ ++J;
+ }
+ }
+ Partitions.erase(std::unique(Partitions.begin(), Partitions.end()),
+ Partitions.end());
+
+ // Split splittable and merge unsplittable partitions into a disjoint set
+ // of partitions over the used space of the allocation.
+ splitAndMergePartitions();
+ }
+
+ // Now build up the user lists for each of these disjoint partitions by
+ // re-walking the recursive users of the alloca.
+ Uses.resize(Partitions.size());
+ UseBuilder UB(TD, AI, *this);
+ UB();
+ for (iterator I = Partitions.begin(), E = Partitions.end(); I != E; ++I)
+ std::stable_sort(use_begin(I), use_end(I));
+}
+
+Type *AllocaPartitioning::getCommonType(iterator I) const {
+ Type *Ty = 0;
+ for (const_use_iterator UI = use_begin(I), UE = use_end(I); UI != UE; ++UI) {
+ if (isa<MemIntrinsic>(*UI->User))
+ continue;
+ if (UI->BeginOffset != I->BeginOffset || UI->EndOffset != I->EndOffset)
+ break;
+
+ Type *UserTy = 0;
+ if (LoadInst *LI = dyn_cast<LoadInst>(&*UI->User)) {
+ UserTy = LI->getType();
+ } else if (StoreInst *SI = dyn_cast<StoreInst>(&*UI->User)) {
+ UserTy = SI->getValueOperand()->getType();
+ } else if (SelectInst *SI = dyn_cast<SelectInst>(&*UI->User)) {
+ if (PointerType *PtrTy = dyn_cast<PointerType>(SI->getType()))
+ UserTy = PtrTy->getElementType();
+ } else if (PHINode *PN = dyn_cast<PHINode>(&*UI->User)) {
+ if (PointerType *PtrTy = dyn_cast<PointerType>(PN->getType()))
+ UserTy = PtrTy->getElementType();
+ }
+
+ if (Ty && Ty != UserTy)
+ return 0;
+
+ Ty = UserTy;
+ }
+ return Ty;
+}
+
+void AllocaPartitioning::print(raw_ostream &OS, const_iterator I,
+ StringRef Indent) const {
+ OS << Indent << "partition #" << (I - begin())
+ << " [" << I->BeginOffset << "," << I->EndOffset << ")"
+ << (I->IsSplittable ? " (splittable)" : "")
+ << (Uses[I - begin()].empty() ? " (zero uses)" : "")
+ << "\n";
+}
+
+void AllocaPartitioning::printUsers(raw_ostream &OS, const_iterator I,
+ StringRef Indent) const {
+ for (const_use_iterator UI = use_begin(I), UE = use_end(I);
+ UI != UE; ++UI) {
+ OS << Indent << " [" << UI->BeginOffset << "," << UI->EndOffset << ") "
+ << "used by: " << *UI->User << "\n";
+ if (MemTransferInst *II = dyn_cast<MemTransferInst>(&*UI->User)) {
+ const MemTransferOffsets &MTO = MemTransferInstData.lookup(II);
+ bool IsDest;
+ if (!MTO.IsSplittable)
+ IsDest = UI->BeginOffset == MTO.DestBegin;
+ else
+ IsDest = MTO.DestBegin != 0u;
+ OS << Indent << " (original " << (IsDest ? "dest" : "source") << ": "
+ << "[" << (IsDest ? MTO.DestBegin : MTO.SourceBegin)
+ << "," << (IsDest ? MTO.DestEnd : MTO.SourceEnd) << ")\n";
+ }
+ }
+}
+
+void AllocaPartitioning::print(raw_ostream &OS) const {
+ if (PointerEscapingInstr) {
+ OS << "No partitioning for alloca: " << AI << "\n"
+ << " A pointer to this alloca escaped by:\n"
+ << " " << *PointerEscapingInstr << "\n";
+ return;
+ }
+
+ OS << "Partitioning of alloca: " << AI << "\n";
+ unsigned Num = 0;
+ for (const_iterator I = begin(), E = end(); I != E; ++I, ++Num) {
+ print(OS, I);
+ printUsers(OS, I);
+ }
+}
+
+void AllocaPartitioning::dump(const_iterator I) const { print(dbgs(), I); }
+void AllocaPartitioning::dump() const { print(dbgs()); }
+
+
+namespace {
+/// \brief An optimization pass providing Scalar Replacement of Aggregates.
+///
+/// This pass takes allocations which can be completely analyzed (that is, they
+/// don't escape) and tries to turn them into scalar SSA values. There are
+/// a few steps to this process.
+///
+/// 1) It takes allocations of aggregates and analyzes the ways in which they
+/// are used to try to split them into smaller allocations, ideally of
+/// a single scalar data type. It will split up memcpy and memset accesses
+/// as necessary and try to isolate invidual scalar accesses.
+/// 2) It will transform accesses into forms which are suitable for SSA value
+/// promotion. This can be replacing a memset with a scalar store of an
+/// integer value, or it can involve speculating operations on a PHI or
+/// select to be a PHI or select of the results.
+/// 3) Finally, this will try to detect a pattern of accesses which map cleanly
+/// onto insert and extract operations on a vector value, and convert them to
+/// this form. By doing so, it will enable promotion of vector aggregates to
+/// SSA vector values.
+class SROA : public FunctionPass {
+ LLVMContext *C;
+ const TargetData *TD;
+ DominatorTree *DT;
+
+ /// \brief Worklist of alloca instructions to simplify.
+ ///
+ /// Each alloca in the function is added to this. Each new alloca formed gets
+ /// added to it as well to recursively simplify unless that alloca can be
+ /// directly promoted. Finally, each time we rewrite a use of an alloca other
+ /// the one being actively rewritten, we add it back onto the list if not
+ /// already present to ensure it is re-visited.
+ SetVector<AllocaInst *, SmallVector<AllocaInst *, 16> > Worklist;
+
+ /// \brief A collection of instructions to delete.
+ /// We try to batch deletions to simplify code and make things a bit more
+ /// efficient.
+ SmallVector<Instruction *, 8> DeadInsts;
+
+ /// \brief A set to prevent repeatedly marking an instruction split into many
+ /// uses as dead. Only used to guard insertion into DeadInsts.
+ SmallPtrSet<Instruction *, 4> DeadSplitInsts;
+
+ /// \brief A set of deleted alloca instructions.
+ ///
+ /// These pointers are *no longer valid* as they have been deleted. They are
+ /// used to remove deleted allocas from the list of promotable allocas.
+ SmallPtrSet<AllocaInst *, 4> DeletedAllocas;
+
+ /// \brief A collection of alloca instructions we can directly promote.
+ std::vector<AllocaInst *> PromotableAllocas;
+
+public:
+ SROA() : FunctionPass(ID), C(0), TD(0), DT(0) {
+ initializeSROAPass(*PassRegistry::getPassRegistry());
+ }
+ bool runOnFunction(Function &F);
+ void getAnalysisUsage(AnalysisUsage &AU) const;
+
+ const char *getPassName() const { return "SROA"; }
+ static char ID;
+
+private:
+ friend class AllocaPartitionRewriter;
+ friend class AllocaPartitionVectorRewriter;
+
+ bool rewriteAllocaPartition(AllocaInst &AI,
+ AllocaPartitioning &P,
+ AllocaPartitioning::iterator PI);
+ bool splitAlloca(AllocaInst &AI, AllocaPartitioning &P);
+ bool runOnAlloca(AllocaInst &AI);
+ void deleteDeadInstructions();
+};
+}
+
+char SROA::ID = 0;
+
+FunctionPass *llvm::createSROAPass() {
+ return new SROA();
+}
+
+INITIALIZE_PASS_BEGIN(SROA, "sroa", "Scalar Replacement Of Aggregates",
+ false, false)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_END(SROA, "sroa", "Scalar Replacement Of Aggregates",
+ false, false)
+
+/// \brief Accumulate the constant offsets in a GEP into a single APInt offset.
+///
+/// If the provided GEP is all-constant, the total byte offset formed by the
+/// GEP is computed and Offset is set to it. If the GEP has any non-constant
+/// operands, the function returns false and the value of Offset is unmodified.
+static bool accumulateGEPOffsets(const TargetData &TD, GEPOperator &GEP,
+ APInt &Offset) {
+ APInt GEPOffset(Offset.getBitWidth(), 0);
+ for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP);
+ GTI != GTE; ++GTI) {
+ ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
+ if (!OpC)
+ return false;
+ if (OpC->isZero()) continue;
+
+ // Handle a struct index, which adds its field offset to the pointer.
+ if (StructType *STy = dyn_cast<StructType>(*GTI)) {
+ unsigned ElementIdx = OpC->getZExtValue();
+ const StructLayout *SL = TD.getStructLayout(STy);
+ GEPOffset += APInt(Offset.getBitWidth(),
+ SL->getElementOffset(ElementIdx));
+ continue;
+ }
+
+ APInt TypeSize(Offset.getBitWidth(),
+ TD.getTypeAllocSize(GTI.getIndexedType()));
+ if (VectorType *VTy = dyn_cast<VectorType>(*GTI)) {
+ assert((VTy->getScalarSizeInBits() % 8) == 0 &&
+ "vector element size is not a multiple of 8, cannot GEP over it");
+ TypeSize = VTy->getScalarSizeInBits() / 8;
+ }
+
+ GEPOffset += OpC->getValue().sextOrTrunc(Offset.getBitWidth()) * TypeSize;
+ }
+ Offset = GEPOffset;
+ return true;
+}
+
+/// \brief Build a GEP out of a base pointer and indices.
+///
+/// This will return the BasePtr if that is valid, or build a new GEP
+/// instruction using the IRBuilder if GEP-ing is needed.
+static Value *buildGEP(IRBuilder<> &IRB, Value *BasePtr,
+ SmallVectorImpl<Value *> &Indices,
+ const Twine &Prefix) {
+ if (Indices.empty())
+ return BasePtr;
+
+ // A single zero index is a no-op, so check for this and avoid building a GEP
+ // in that case.
+ if (Indices.size() == 1 && cast<ConstantInt>(Indices.back())->isZero())
+ return BasePtr;
+
+ return IRB.CreateInBoundsGEP(BasePtr, Indices, Prefix + ".idx");
+}
+
+/// \brief Get a natural GEP off of the BasePtr walking through Ty toward
+/// TargetTy without changing the offset of the pointer.
+///
+/// This routine assumes we've already established a properly offset GEP with
+/// Indices, and arrived at the Ty type. The goal is to continue to GEP with
+/// zero-indices down through type layers until we find one the same as
+/// TargetTy. If we can't find one with the same type, we at least try to use
+/// one with the same size. If none of that works, we just produce the GEP as
+/// indicated by Indices to have the correct offset.
+static Value *getNaturalGEPWithType(IRBuilder<> &IRB, const TargetData &TD,
+ Value *BasePtr, Type *Ty, Type *TargetTy,
+ SmallVectorImpl<Value *> &Indices,
+ const Twine &Prefix) {
+ if (Ty == TargetTy)
+ return buildGEP(IRB, BasePtr, Indices, Prefix);
+
+ // See if we can descend into a struct and locate a field with the correct
+ // type.
+ unsigned NumLayers = 0;
+ Type *ElementTy = Ty;
+ do {
+ if (ElementTy->isPointerTy())
+ break;
+ if (SequentialType *SeqTy = dyn_cast<SequentialType>(ElementTy)) {
+ ElementTy = SeqTy->getElementType();
+ Indices.push_back(IRB.getInt(APInt(TD.getPointerSizeInBits(), 0)));
+ } else if (StructType *STy = dyn_cast<StructType>(ElementTy)) {
+ ElementTy = *STy->element_begin();
+ Indices.push_back(IRB.getInt32(0));
+ } else {
+ break;
+ }
+ ++NumLayers;
+ } while (ElementTy != TargetTy);
+ if (ElementTy != TargetTy)
+ Indices.erase(Indices.end() - NumLayers, Indices.end());
+
+ return buildGEP(IRB, BasePtr, Indices, Prefix);
+}
+
+/// \brief Recursively compute indices for a natural GEP.
+///
+/// This is the recursive step for getNaturalGEPWithOffset that walks down the
+/// element types adding appropriate indices for the GEP.
+static Value *getNaturalGEPRecursively(IRBuilder<> &IRB, const TargetData &TD,
+ Value *Ptr, Type *Ty, APInt &Offset,
+ Type *TargetTy,
+ SmallVectorImpl<Value *> &Indices,
+ const Twine &Prefix) {
+ if (Offset == 0)
+ return getNaturalGEPWithType(IRB, TD, Ptr, Ty, TargetTy, Indices, Prefix);
+
+ // We can't recurse through pointer types.
+ if (Ty->isPointerTy())
+ return 0;
+
+ if (VectorType *VecTy = dyn_cast<VectorType>(Ty)) {
+ unsigned ElementSizeInBits = VecTy->getScalarSizeInBits();
+ if (ElementSizeInBits % 8)
+ return 0; // GEPs over multiple of 8 size vector elements are invalid.
+ APInt ElementSize(Offset.getBitWidth(), ElementSizeInBits / 8);
+ APInt NumSkippedElements = Offset.udiv(ElementSize);
+ if (NumSkippedElements.ugt(VecTy->getNumElements()))
+ return 0;
+ Offset -= NumSkippedElements * ElementSize;
+ Indices.push_back(IRB.getInt(NumSkippedElements));
+ return getNaturalGEPRecursively(IRB, TD, Ptr, VecTy->getElementType(),
+ Offset, TargetTy, Indices, Prefix);
+ }
+
+ if (ArrayType *ArrTy = dyn_cast<ArrayType>(Ty)) {
+ Type *ElementTy = ArrTy->getElementType();
+ APInt ElementSize(Offset.getBitWidth(), TD.getTypeAllocSize(ElementTy));
+ APInt NumSkippedElements = Offset.udiv(ElementSize);
+ if (NumSkippedElements.ugt(ArrTy->getNumElements()))
+ return 0;
+
+ Offset -= NumSkippedElements * ElementSize;
+ Indices.push_back(IRB.getInt(NumSkippedElements));
+ return getNaturalGEPRecursively(IRB, TD, Ptr, ElementTy, Offset, TargetTy,
+ Indices, Prefix);
+ }
+
+ StructType *STy = dyn_cast<StructType>(Ty);
+ if (!STy)
+ return 0;
+
+ const StructLayout *SL = TD.getStructLayout(STy);
+ uint64_t StructOffset = Offset.getZExtValue();
+ if (StructOffset > SL->getSizeInBytes())
+ return 0;
+ unsigned Index = SL->getElementContainingOffset(StructOffset);
+ Offset -= APInt(Offset.getBitWidth(), SL->getElementOffset(Index));
+ Type *ElementTy = STy->getElementType(Index);
+ if (Offset.uge(TD.getTypeAllocSize(ElementTy)))
+ return 0; // The offset points into alignment padding.
+
+ Indices.push_back(IRB.getInt32(Index));
+ return getNaturalGEPRecursively(IRB, TD, Ptr, ElementTy, Offset, TargetTy,
+ Indices, Prefix);
+}
+
+/// \brief Get a natural GEP from a base pointer to a particular offset and
+/// resulting in a particular type.
+///
+/// The goal is to produce a "natural" looking GEP that works with the existing
+/// composite types to arrive at the appropriate offset and element type for
+/// a pointer. TargetTy is the element type the returned GEP should point-to if
+/// possible. We recurse by decreasing Offset, adding the appropriate index to
+/// Indices, and setting Ty to the result subtype.
+///
+/// If no natural GEP can be constructed, this function returns a null Value*.
+static Value *getNaturalGEPWithOffset(IRBuilder<> &IRB, const TargetData &TD,
+ Value *Ptr, APInt Offset, Type *TargetTy,
+ SmallVectorImpl<Value *> &Indices,
+ const Twine &Prefix) {
+ PointerType *Ty = cast<PointerType>(Ptr->getType());
+
+ // Don't consider any GEPs through an i8* as natural unless the TargetTy is
+ // an i8.
+ if (Ty == IRB.getInt8PtrTy() && TargetTy->isIntegerTy(8))
+ return 0;
+
+ Type *ElementTy = Ty->getElementType();
+ APInt ElementSize(Offset.getBitWidth(), TD.getTypeAllocSize(ElementTy));
+ if (ElementSize == 0)
+ return 0; // Zero-length arrays can't help us build a natural GEP.
+ APInt NumSkippedElements = Offset.udiv(ElementSize);
+
+ Offset -= NumSkippedElements * ElementSize;
+ Indices.push_back(IRB.getInt(NumSkippedElements));
+ return getNaturalGEPRecursively(IRB, TD, Ptr, ElementTy, Offset, TargetTy,
+ Indices, Prefix);
+}
+
+/// \brief Compute an adjusted pointer from Ptr by Offset bytes where the
+/// resulting pointer has PointerTy.
+///
+/// This tries very hard to compute a "natural" GEP which arrives at the offset
+/// and produces the pointer type desired. Where it cannot, it will try to use
+/// the natural GEP to arrive at the offset and bitcast to the type. Where that
+/// fails, it will try to use an existing i8* and GEP to the byte offset and
+/// bitcast to the type.
+///
+/// The strategy for finding the more natural GEPs is to peel off layers of the
+/// pointer, walking back through bit casts and GEPs, searching for a base
+/// pointer from which we can compute a natural GEP with the desired
+/// properities. The algorithm tries to fold as many constant indices into
+/// a single GEP as possible, thus making each GEP more independent of the
+/// surrounding code.
+static Value *getAdjustedPtr(IRBuilder<> &IRB, const TargetData &TD,
+ Value *Ptr, APInt Offset, Type *PointerTy,
+ const Twine &Prefix) {
+ // Even though we don't look through PHI nodes, we could be called on an
+ // instruction in an unreachable block, which may be on a cycle.
+ SmallPtrSet<Value *, 4> Visited;
+ Visited.insert(Ptr);
+ SmallVector<Value *, 4> Indices;
+
+ // We may end up computing an offset pointer that has the wrong type. If we
+ // never are able to compute one directly that has the correct type, we'll
+ // fall back to it, so keep it around here.
+ Value *OffsetPtr = 0;
+
+ // Remember any i8 pointer we come across to re-use if we need to do a raw
+ // byte offset.
+ Value *Int8Ptr = 0;
+ APInt Int8PtrOffset(Offset.getBitWidth(), 0);
+
+ Type *TargetTy = PointerTy->getPointerElementType();
+
+ do {
+ // First fold any existing GEPs into the offset.
+ while (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
+ APInt GEPOffset(Offset.getBitWidth(), 0);
+ if (!accumulateGEPOffsets(TD, *GEP, GEPOffset))
+ break;
+ Offset += GEPOffset;
+ Ptr = GEP->getPointerOperand();
+ if (!Visited.insert(Ptr))
+ break;
+ }
+
+ // See if we can perform a natural GEP here.
+ Indices.clear();
+ if (Value *P = getNaturalGEPWithOffset(IRB, TD, Ptr, Offset, TargetTy,
+ Indices, Prefix)) {
+ if (P->getType() == PointerTy) {
+ // Zap any offset pointer that we ended up computing in previous rounds.
+ if (OffsetPtr && OffsetPtr->use_empty())
+ if (Instruction *I = dyn_cast<Instruction>(OffsetPtr))
+ I->eraseFromParent();
+ return P;
+ }
+ if (!OffsetPtr) {
+ OffsetPtr = P;
+ }
+ }
+
+ // Stash this pointer if we've found an i8*.
+ if (Ptr->getType()->isIntegerTy(8)) {
+ Int8Ptr = Ptr;
+ Int8PtrOffset = Offset;
+ }
+
+ // Peel off a layer of the pointer and update the offset appropriately.
+ if (Operator::getOpcode(Ptr) == Instruction::BitCast) {
+ Ptr = cast<Operator>(Ptr)->getOperand(0);
+ } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(Ptr)) {
+ if (GA->mayBeOverridden())
+ break;
+ Ptr = GA->getAliasee();
+ } else {
+ break;
+ }
+ assert(Ptr->getType()->isPointerTy() && "Unexpected operand type!");
+ } while (Visited.insert(Ptr));
+
+ if (!OffsetPtr) {
+ if (!Int8Ptr) {
+ Int8Ptr = IRB.CreateBitCast(Ptr, IRB.getInt8PtrTy(),
+ Prefix + ".raw_cast");
+ Int8PtrOffset = Offset;
+ }
+
+ OffsetPtr = Int8PtrOffset == 0 ? Int8Ptr :
+ IRB.CreateInBoundsGEP(Int8Ptr, IRB.getInt(Int8PtrOffset),
+ Prefix + ".raw_idx");
+ }
+ Ptr = OffsetPtr;
+
+ // On the off chance we were targeting i8*, guard the bitcast here.
+ if (Ptr->getType() != PointerTy)
+ Ptr = IRB.CreateBitCast(Ptr, PointerTy, Prefix + ".cast");
+
+ return Ptr;
+}
+
+/// \brief Test whether the given alloca partition can be promoted to a vector.
+///
+/// This is a quick test to check whether we can rewrite a particular alloca
+/// partition (and its newly formed alloca) into a vector alloca with only
+/// whole-vector loads and stores such that it could be promoted to a vector
+/// SSA value. We only can ensure this for a limited set of operations, and we
+/// don't want to do the rewrites unless we are confident that the result will
+/// be promotable, so we have an early test here.
+static bool isVectorPromotionViable(const TargetData &TD,
+ Type *AllocaTy,
+ AllocaPartitioning &P,
+ uint64_t PartitionBeginOffset,
+ uint64_t PartitionEndOffset,
+ AllocaPartitioning::const_use_iterator I,
+ AllocaPartitioning::const_use_iterator E) {
+ VectorType *Ty = dyn_cast<VectorType>(AllocaTy);
+ if (!Ty)
+ return false;
+
+ uint64_t VecSize = TD.getTypeSizeInBits(Ty);
+ uint64_t ElementSize = Ty->getScalarSizeInBits();
+
+ // While the definition of LLVM vectors is bitpacked, we don't support sizes
+ // that aren't byte sized.
+ if (ElementSize % 8)
+ return false;
+ assert((VecSize % 8) == 0 && "vector size not a multiple of element size?");
+ VecSize /= 8;
+ ElementSize /= 8;
+
+ for (; I != E; ++I) {
+ uint64_t BeginOffset = I->BeginOffset - PartitionBeginOffset;
+ uint64_t BeginIndex = BeginOffset / ElementSize;
+ if (BeginIndex * ElementSize != BeginOffset ||
+ BeginIndex >= Ty->getNumElements())
+ return false;
+ uint64_t EndOffset = I->EndOffset - PartitionBeginOffset;
+ uint64_t EndIndex = EndOffset / ElementSize;
+ if (EndIndex * ElementSize != EndOffset ||
+ EndIndex > Ty->getNumElements())
+ return false;
+
+ // FIXME: We should build shuffle vector instructions to handle
+ // non-element-sized accesses.
+ if ((EndOffset - BeginOffset) != ElementSize &&
+ (EndOffset - BeginOffset) != VecSize)
+ return false;
+
+ if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(&*I->User)) {
+ if (MI->isVolatile())
+ return false;
+ if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(&*I->User)) {
+ const AllocaPartitioning::MemTransferOffsets &MTO
+ = P.getMemTransferOffsets(*MTI);
+ if (!MTO.IsSplittable)
+ return false;
+ }
+ } else if (I->Ptr->getType()->getPointerElementType()->isStructTy()) {
+ // Disable vector promotion when there are loads or stores of an FCA.
+ return false;
+ } else if (!isa<LoadInst>(*I->User) && !isa<StoreInst>(*I->User)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+namespace {
+/// \brief Visitor to rewrite instructions using a partition of an alloca to
+/// use a new alloca.
+///
+/// Also implements the rewriting to vector-based accesses when the partition
+/// passes the isVectorPromotionViable predicate. Most of the rewriting logic
+/// lives here.
+class AllocaPartitionRewriter : public InstVisitor<AllocaPartitionRewriter,
+ bool> {
+ // Befriend the base class so it can delegate to private visit methods.
+ friend class llvm::InstVisitor<AllocaPartitionRewriter, bool>;
+
+ const TargetData &TD;
+ AllocaPartitioning &P;
+ SROA &Pass;
+ AllocaInst &OldAI, &NewAI;
+ const uint64_t NewAllocaBeginOffset, NewAllocaEndOffset;
+
+ // If we are rewriting an alloca partition which can be written as pure
+ // vector operations, we stash extra information here. When VecTy is
+ // non-null, we have some strict guarantees about the rewriten alloca:
+ // - The new alloca is exactly the size of the vector type here.
+ // - The accesses all either map to the entire vector or to a single
+ // element.
+ // - The set of accessing instructions is only one of those handled above
+ // in isVectorPromotionViable. Generally these are the same access kinds
+ // which are promotable via mem2reg.
+ VectorType *VecTy;
+ Type *ElementTy;
+ uint64_t ElementSize;
+
+ // The offset of the partition user currently being rewritten.
+ uint64_t BeginOffset, EndOffset;
+ Instruction *OldPtr;
+
+ // The name prefix to use when rewriting instructions for this alloca.
+ std::string NamePrefix;
+
+public:
+ AllocaPartitionRewriter(const TargetData &TD, AllocaPartitioning &P,
+ AllocaPartitioning::iterator PI,
+ SROA &Pass, AllocaInst &OldAI, AllocaInst &NewAI,
+ uint64_t NewBeginOffset, uint64_t NewEndOffset)
+ : TD(TD), P(P), Pass(Pass),
+ OldAI(OldAI), NewAI(NewAI),
+ NewAllocaBeginOffset(NewBeginOffset),
+ NewAllocaEndOffset(NewEndOffset),
+ VecTy(), ElementTy(), ElementSize(),
+ BeginOffset(), EndOffset() {
+ }
+
+ /// \brief Visit the users of the alloca partition and rewrite them.
+ bool visitUsers(AllocaPartitioning::const_use_iterator I,
+ AllocaPartitioning::const_use_iterator E) {
+ if (isVectorPromotionViable(TD, NewAI.getAllocatedType(), P,
+ NewAllocaBeginOffset, NewAllocaEndOffset,
+ I, E)) {
+ ++NumVectorized;
+ VecTy = cast<VectorType>(NewAI.getAllocatedType());
+ ElementTy = VecTy->getElementType();
+ assert((VecTy->getScalarSizeInBits() % 8) == 0 &&
+ "Only multiple-of-8 sized vector elements are viable");
+ ElementSize = VecTy->getScalarSizeInBits() / 8;
+ }
+ bool CanSROA = true;
+ for (; I != E; ++I) {
+ BeginOffset = I->BeginOffset;
+ EndOffset = I->EndOffset;
+ OldPtr = I->Ptr;
+ NamePrefix = (Twine(NewAI.getName()) + "." + Twine(BeginOffset)).str();
+ CanSROA &= visit(I->User);
+ }
+ if (VecTy) {
+ assert(CanSROA);
+ VecTy = 0;
+ ElementTy = 0;
+ ElementSize = 0;
+ }
+ return CanSROA;
+ }
+
+private:
+ // Every instruction which can end up as a user must have a rewrite rule.
+ bool visitInstruction(Instruction &I) {
+ DEBUG(dbgs() << " !!!! Cannot rewrite: " << I << "\n");
+ llvm_unreachable("No rewrite rule for this instruction!");
+ }
+
+ Twine getName(const Twine &Suffix) {
+ return NamePrefix + Suffix;
+ }
+
+ Value *getAdjustedAllocaPtr(IRBuilder<> &IRB, Type *PointerTy) {
+ assert(BeginOffset >= NewAllocaBeginOffset);
+ APInt Offset(TD.getPointerSizeInBits(), BeginOffset - NewAllocaBeginOffset);
+ return getAdjustedPtr(IRB, TD, &NewAI, Offset, PointerTy, getName(""));
+ }
+
+ ConstantInt *getIndex(IRBuilder<> &IRB, uint64_t Offset) {
+ assert(VecTy && "Can only call getIndex when rewriting a vector");
+ uint64_t RelOffset = Offset - NewAllocaBeginOffset;
+ assert(RelOffset / ElementSize < UINT32_MAX && "Index out of bounds");
+ uint32_t Index = RelOffset / ElementSize;
+ assert(Index * ElementSize == RelOffset);
+ return IRB.getInt32(Index);
+ }
+
+ void deleteIfTriviallyDead(Value *V) {
+ Instruction *I = cast<Instruction>(V);
+ if (isInstructionTriviallyDead(I))
+ Pass.DeadInsts.push_back(I);
+ }
+
+ Value *getValueCast(IRBuilder<> &IRB, Value *V, Type *Ty) {
+ if (V->getType()->isIntegerTy() && Ty->isPointerTy())
+ return IRB.CreateIntToPtr(V, Ty);
+ if (V->getType()->isPointerTy() && Ty->isIntegerTy())
+ return IRB.CreatePtrToInt(V, Ty);
+
+ return IRB.CreateBitCast(V, Ty);
+ }
+
+ bool rewriteVectorizedLoadInst(IRBuilder<> &IRB, LoadInst &LI, Value *OldOp) {
+ Value *Result;
+ if (LI.getType() == VecTy->getElementType() ||
+ BeginOffset > NewAllocaBeginOffset || EndOffset < NewAllocaEndOffset) {
+ Result
+ = IRB.CreateExtractElement(IRB.CreateLoad(&NewAI, getName(".load")),
+ getIndex(IRB, BeginOffset),
+ getName(".extract"));
+ } else {
+ Result = IRB.CreateLoad(&NewAI, getName(".load"));
+ }
+ if (Result->getType() != LI.getType())
+ Result = getValueCast(IRB, Result, LI.getType());
+ LI.replaceAllUsesWith(Result);
+ Pass.DeadInsts.push_back(&LI);
+
+ DEBUG(dbgs() << " to: " << *Result << "\n");
+ return true;
+ }
+
+ bool visitLoadInst(LoadInst &LI) {
+ DEBUG(dbgs() << " original: " << LI << "\n");
+ Value *OldOp = LI.getOperand(0);
+ assert(OldOp == OldPtr);
+ IRBuilder<> IRB(&LI);
+
+ if (VecTy)
+ return rewriteVectorizedLoadInst(IRB, LI, OldOp);
+
+ Value *NewPtr = getAdjustedAllocaPtr(IRB,
+ LI.getPointerOperand()->getType());
+ LI.setOperand(0, NewPtr);
+ DEBUG(dbgs() << " to: " << LI << "\n");
+
+ deleteIfTriviallyDead(OldOp);
+ return NewPtr == &NewAI && !LI.isVolatile();
+ }
+
+ bool rewriteVectorizedStoreInst(IRBuilder<> &IRB, StoreInst &SI,
+ Value *OldOp) {
+ Value *V = SI.getValueOperand();
+ if (V->getType() == ElementTy ||
+ BeginOffset > NewAllocaBeginOffset || EndOffset < NewAllocaEndOffset) {
+ if (V->getType() != ElementTy)
+ V = getValueCast(IRB, V, ElementTy);
+ V = IRB.CreateInsertElement(IRB.CreateLoad(&NewAI, getName(".load")), V,
+ getIndex(IRB, BeginOffset),
+ getName(".insert"));
+ } else if (V->getType() != VecTy) {
+ V = getValueCast(IRB, V, VecTy);
+ }
+ StoreInst *Store = IRB.CreateStore(V, &NewAI);
+ Pass.DeadInsts.push_back(&SI);
+
+ (void)Store;
+ DEBUG(dbgs() << " to: " << *Store << "\n");
+ return true;
+ }
+
+ bool visitStoreInst(StoreInst &SI) {
+ DEBUG(dbgs() << " original: " << SI << "\n");
+ Value *OldOp = SI.getOperand(1);
+ assert(OldOp == OldPtr);
+ IRBuilder<> IRB(&SI);
+
+ if (VecTy)
+ return rewriteVectorizedStoreInst(IRB, SI, OldOp);
+
+ Value *NewPtr = getAdjustedAllocaPtr(IRB,
+ SI.getPointerOperand()->getType());
+ SI.setOperand(1, NewPtr);
+ DEBUG(dbgs() << " to: " << SI << "\n");
+
+ deleteIfTriviallyDead(OldOp);
+ return NewPtr == &NewAI && !SI.isVolatile();
+ }
+
+ bool visitMemSetInst(MemSetInst &II) {
+ DEBUG(dbgs() << " original: " << II << "\n");
+ IRBuilder<> IRB(&II);
+ assert(II.getRawDest() == OldPtr);
+
+ // If the memset has a variable size, it cannot be split, just adjust the
+ // pointer to the new alloca.
+ if (!isa<Constant>(II.getLength())) {
+ II.setDest(getAdjustedAllocaPtr(IRB, II.getRawDest()->getType()));
+ deleteIfTriviallyDead(OldPtr);
+ return false;
+ }
+
+ // Record this instruction for deletion.
+ if (Pass.DeadSplitInsts.insert(&II))
+ Pass.DeadInsts.push_back(&II);
+
+ Type *AllocaTy = NewAI.getAllocatedType();
+ Type *ScalarTy = AllocaTy->getScalarType();
+
+ // If this doesn't map cleanly onto the alloca type, and that type isn't
+ // a single value type, just emit a memset.
+ if (!VecTy && (BeginOffset != NewAllocaBeginOffset ||
+ EndOffset != NewAllocaEndOffset ||
+ !AllocaTy->isSingleValueType() ||
+ !TD.isLegalInteger(TD.getTypeSizeInBits(ScalarTy)))) {
+ Type *SizeTy = II.getLength()->getType();
+ Constant *Size = ConstantInt::get(SizeTy, EndOffset - BeginOffset);
+
+ CallInst *New
+ = IRB.CreateMemSet(getAdjustedAllocaPtr(IRB,
+ II.getRawDest()->getType()),
+ II.getValue(), Size, II.getAlignment(),
+ II.isVolatile());
+ (void)New;
+ DEBUG(dbgs() << " to: " << *New << "\n");
+ return false;
+ }
+
+ // If we can represent this as a simple value, we have to build the actual
+ // value to store, which requires expanding the byte present in memset to
+ // a sensible representation for the alloca type. This is essentially
+ // splatting the byte to a sufficiently wide integer, bitcasting to the
+ // desired scalar type, and splatting it across any desired vector type.
+ Value *V = II.getValue();
+ IntegerType *VTy = cast<IntegerType>(V->getType());
+ Type *IntTy = Type::getIntNTy(VTy->getContext(),
+ TD.getTypeSizeInBits(ScalarTy));
+ if (TD.getTypeSizeInBits(ScalarTy) > VTy->getBitWidth())
+ V = IRB.CreateMul(IRB.CreateZExt(V, IntTy, getName(".zext")),
+ ConstantExpr::getUDiv(
+ Constant::getAllOnesValue(IntTy),
+ ConstantExpr::getZExt(
+ Constant::getAllOnesValue(V->getType()),
+ IntTy)),
+ getName(".isplat"));
+ if (V->getType() != ScalarTy) {
+ if (ScalarTy->isPointerTy())
+ V = IRB.CreateIntToPtr(V, ScalarTy);
+ else if (ScalarTy->isPrimitiveType() || ScalarTy->isVectorTy())
+ V = IRB.CreateBitCast(V, ScalarTy);
+ else if (ScalarTy->isIntegerTy())
+ llvm_unreachable("Computed different integer types with equal widths");
+ else
+ llvm_unreachable("Invalid scalar type");
+ }
+
+ // If this is an element-wide memset of a vectorizable alloca, insert it.
+ if (VecTy && (BeginOffset > NewAllocaBeginOffset ||
+ EndOffset < NewAllocaEndOffset)) {
+ StoreInst *Store = IRB.CreateStore(
+ IRB.CreateInsertElement(IRB.CreateLoad(&NewAI, getName(".load")), V,
+ getIndex(IRB, BeginOffset),
+ getName(".insert")),
+ &NewAI);
+ (void)Store;
+ DEBUG(dbgs() << " to: " << *Store << "\n");
+ return true;
+ }
+
+ // Splat to a vector if needed.
+ if (VectorType *VecTy = dyn_cast<VectorType>(AllocaTy)) {
+ VectorType *SplatSourceTy = VectorType::get(V->getType(), 1);
+ V = IRB.CreateShuffleVector(
+ IRB.CreateInsertElement(UndefValue::get(SplatSourceTy), V,
+ IRB.getInt32(0), getName(".vsplat.insert")),
+ UndefValue::get(SplatSourceTy),
+ ConstantVector::getSplat(VecTy->getNumElements(), IRB.getInt32(0)),
+ getName(".vsplat.shuffle"));
+ assert(V->getType() == VecTy);
+ }
+
+ Value *New = IRB.CreateStore(V, &NewAI, II.isVolatile());
+ (void)New;
+ DEBUG(dbgs() << " to: " << *New << "\n");
+ return !II.isVolatile();
+ }
+
+ bool visitMemTransferInst(MemTransferInst &II) {
+ // Rewriting of memory transfer instructions can be a bit tricky. We break
+ // them into two categories: split intrinsics and unsplit intrinsics.
+
+ DEBUG(dbgs() << " original: " << II << "\n");
+ IRBuilder<> IRB(&II);
+
+ assert(II.getRawSource() == OldPtr || II.getRawDest() == OldPtr);
+ bool IsDest = II.getRawDest() == OldPtr;
+
+ const AllocaPartitioning::MemTransferOffsets &MTO
+ = P.getMemTransferOffsets(II);
+
+ // For unsplit intrinsics, we simply modify the source and destination
+ // pointers in place. This isn't just an optimization, it is a matter of
+ // correctness. With unsplit intrinsics we may be dealing with transfers
+ // within a single alloca before SROA ran, or with transfers that have
+ // a variable length. We may also be dealing with memmove instead of
+ // memcpy, and so simply updating the pointers is the necessary for us to
+ // update both source and dest of a single call.
+ if (!MTO.IsSplittable) {
+ Value *OldOp = IsDest ? II.getRawDest() : II.getRawSource();
+ if (IsDest)
+ II.setDest(getAdjustedAllocaPtr(IRB, II.getRawDest()->getType()));
+ else
+ II.setSource(getAdjustedAllocaPtr(IRB, II.getRawSource()->getType()));
+
+ DEBUG(dbgs() << " to: " << II << "\n");
+ deleteIfTriviallyDead(OldOp);
+ return false;
+ }
+ // For split transfer intrinsics we have an incredibly useful assurance:
+ // the source and destination do not reside within the same alloca, and at
+ // least one of them does not escape. This means that we can replace
+ // memmove with memcpy, and we don't need to worry about all manner of
+ // downsides to splitting and transforming the operations.
+
+ // Compute the relative offset within the transfer.
+ unsigned IntPtrWidth = TD.getPointerSizeInBits();
+ APInt RelOffset(IntPtrWidth, BeginOffset - (IsDest ? MTO.DestBegin
+ : MTO.SourceBegin));
+
+ // If this doesn't map cleanly onto the alloca type, and that type isn't
+ // a single value type, just emit a memcpy.
+ bool EmitMemCpy
+ = !VecTy && (BeginOffset != NewAllocaBeginOffset ||
+ EndOffset != NewAllocaEndOffset ||
+ !NewAI.getAllocatedType()->isSingleValueType());
+
+ // If we're just going to emit a memcpy, the alloca hasn't changed, and the
+ // size hasn't been shrunk based on analysis of the viable range, this is
+ // a no-op.
+ if (EmitMemCpy && &OldAI == &NewAI) {
+ uint64_t OrigBegin = IsDest ? MTO.DestBegin : MTO.SourceBegin;
+ uint64_t OrigEnd = IsDest ? MTO.DestEnd : MTO.SourceEnd;
+ // Ensure the start lines up.
+ assert(BeginOffset == OrigBegin);
+
+ // Rewrite the size as needed.
+ if (EndOffset != OrigEnd)
+ II.setLength(ConstantInt::get(II.getLength()->getType(),
+ EndOffset - BeginOffset));
+ return false;
+ }
+ // Record this instruction for deletion.
+ if (Pass.DeadSplitInsts.insert(&II))
+ Pass.DeadInsts.push_back(&II);
+
+ bool IsVectorElement = VecTy && (BeginOffset > NewAllocaBeginOffset ||
+ EndOffset < NewAllocaEndOffset);
+
+ Type *OtherPtrTy = IsDest ? II.getRawSource()->getType()
+ : II.getRawDest()->getType();
+ if (!EmitMemCpy)
+ OtherPtrTy = IsVectorElement ? VecTy->getElementType()->getPointerTo()
+ : NewAI.getType();
+
+ // Compute the other pointer, folding as much as possible to produce
+ // a single, simple GEP in most cases.
+ Value *OtherPtr = IsDest ? II.getRawSource() : II.getRawDest();
+ OtherPtr = getAdjustedPtr(IRB, TD, OtherPtr, RelOffset, OtherPtrTy,
+ getName("." + OtherPtr->getName()));
+
+ // Strip all inbounds GEPs and pointer casts to try to dig out any root
+ // alloca that should be re-examined after rewriting this instruction.
+ if (AllocaInst *AI
+ = dyn_cast<AllocaInst>(OtherPtr->stripInBoundsOffsets()))
+ Pass.Worklist.insert(AI);
+
+ if (EmitMemCpy) {
+ Value *OurPtr
+ = getAdjustedAllocaPtr(IRB, IsDest ? II.getRawDest()->getType()
+ : II.getRawSource()->getType());
+ Type *SizeTy = II.getLength()->getType();
+ Constant *Size = ConstantInt::get(SizeTy, EndOffset - BeginOffset);
+
+ CallInst *New = IRB.CreateMemCpy(IsDest ? OurPtr : OtherPtr,
+ IsDest ? OtherPtr : OurPtr,
+ Size, II.getAlignment(),
+ II.isVolatile());
+ (void)New;
+ DEBUG(dbgs() << " to: " << *New << "\n");
+ return false;
+ }
+
+ Value *SrcPtr = OtherPtr;
+ Value *DstPtr = &NewAI;
+ if (!IsDest)
+ std::swap(SrcPtr, DstPtr);
+
+ Value *Src;
+ if (IsVectorElement && !IsDest) {
+ // We have to extract rather than load.
+ Src = IRB.CreateExtractElement(IRB.CreateLoad(SrcPtr,
+ getName(".copyload")),
+ getIndex(IRB, BeginOffset),
+ getName(".copyextract"));
+ } else {
+ Src = IRB.CreateLoad(SrcPtr, II.isVolatile(), getName(".copyload"));
+ }
+
+ if (IsVectorElement && IsDest) {
+ // We have to insert into a loaded copy before storing.
+ Src = IRB.CreateInsertElement(IRB.CreateLoad(&NewAI, getName(".load")),
+ Src, getIndex(IRB, BeginOffset),
+ getName(".insert"));
+ }
+
+ Value *Store = IRB.CreateStore(Src, DstPtr, II.isVolatile());
+ (void)Store;
+ DEBUG(dbgs() << " to: " << *Store << "\n");
+ return !II.isVolatile();
+ }
+
+ bool visitIntrinsicInst(IntrinsicInst &II) {
+ assert(II.getIntrinsicID() == Intrinsic::lifetime_start ||
+ II.getIntrinsicID() == Intrinsic::lifetime_end);
+ DEBUG(dbgs() << " original: " << II << "\n");
+ IRBuilder<> IRB(&II);
+ assert(II.getArgOperand(1) == OldPtr);
+
+ // Record this instruction for deletion.
+ if (Pass.DeadSplitInsts.insert(&II))
+ Pass.DeadInsts.push_back(&II);
+
+ ConstantInt *Size
+ = ConstantInt::get(cast<IntegerType>(II.getArgOperand(0)->getType()),
+ EndOffset - BeginOffset);
+ Value *Ptr = getAdjustedAllocaPtr(IRB, II.getArgOperand(1)->getType());
+ Value *New;
+ if (II.getIntrinsicID() == Intrinsic::lifetime_start)
+ New = IRB.CreateLifetimeStart(Ptr, Size);
+ else
+ New = IRB.CreateLifetimeEnd(Ptr, Size);
+
+ DEBUG(dbgs() << " to: " << *New << "\n");
+ return true;
+ }
+
+ /// PHI instructions that use an alloca and are subsequently loaded can be
+ /// rewritten to load both input pointers in the pred blocks and then PHI the
+ /// results, allowing the load of the alloca to be promoted.
+ /// From this:
+ /// %P2 = phi [i32* %Alloca, i32* %Other]
+ /// %V = load i32* %P2
+ /// to:
+ /// %V1 = load i32* %Alloca -> will be mem2reg'd
+ /// ...
+ /// %V2 = load i32* %Other
+ /// ...
+ /// %V = phi [i32 %V1, i32 %V2]
+ ///
+ /// We can do this to a select if its only uses are loads and if the operand
+ /// to the select can be loaded unconditionally.
+ ///
+ /// FIXME: This should be hoisted into a generic utility, likely in
+ /// Transforms/Util/Local.h
+ bool isSafePHIToSpeculate(PHINode &PN, SmallVectorImpl<LoadInst *> &Loads) {
+ // For now, we can only do this promotion if the load is in the same block
+ // as the PHI, and if there are no stores between the phi and load.
+ // TODO: Allow recursive phi users.
+ // TODO: Allow stores.
+ BasicBlock *BB = PN.getParent();
+ unsigned MaxAlign = 0;
+ for (Value::use_iterator UI = PN.use_begin(), UE = PN.use_end();
+ UI != UE; ++UI) {
+ LoadInst *LI = dyn_cast<LoadInst>(*UI);
+ if (LI == 0 || !LI->isSimple()) return false;
+
+ // For now we only allow loads in the same block as the PHI. This is
+ // a common case that happens when instcombine merges two loads through
+ // a PHI.
+ if (LI->getParent() != BB) return false;
+
+ // Ensure that there are no instructions between the PHI and the load that
+ // could store.
+ for (BasicBlock::iterator BBI = &PN; &*BBI != LI; ++BBI)
+ if (BBI->mayWriteToMemory())
+ return false;
+
+ MaxAlign = std::max(MaxAlign, LI->getAlignment());
+ Loads.push_back(LI);
+ }
+
+ // We can only transform this if it is safe to push the loads into the
+ // predecessor blocks. The only thing to watch out for is that we can't put
+ // a possibly trapping load in the predecessor if it is a critical edge.
+ for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num;
+ ++Idx) {
+ TerminatorInst *TI = PN.getIncomingBlock(Idx)->getTerminator();
+ Value *InVal = PN.getIncomingValue(Idx);
+
+ // If the value is produced by the terminator of the predecessor (an
+ // invoke) or it has side-effects, there is no valid place to put a load
+ // in the predecessor.
+ if (TI == InVal || TI->mayHaveSideEffects())
+ return false;
+
+ // If the predecessor has a single successor, then the edge isn't
+ // critical.
+ if (TI->getNumSuccessors() == 1)
+ continue;
+
+ // If this pointer is always safe to load, or if we can prove that there
+ // is already a load in the block, then we can move the load to the pred
+ // block.
+ if (InVal->isDereferenceablePointer() ||
+ isSafeToLoadUnconditionally(InVal, TI, MaxAlign, &TD))
+ continue;
+
+ return false;
+ }
+
+ return true;
+ }
+
+ bool visitPHINode(PHINode &PN) {
+ DEBUG(dbgs() << " original: " << PN << "\n");
+ // We would like to compute a new pointer in only one place, but have it be
+ // as local as possible to the PHI. To do that, we re-use the location of
+ // the old pointer, which necessarily must be in the right position to
+ // dominate the PHI.
+ IRBuilder<> PtrBuilder(cast<Instruction>(OldPtr));
+
+ SmallVector<LoadInst *, 4> Loads;
+ if (!isSafePHIToSpeculate(PN, Loads)) {
+ Value *NewPtr = getAdjustedAllocaPtr(PtrBuilder, OldPtr->getType());
+ // Replace the operands which were using the old pointer.
+ User::op_iterator OI = PN.op_begin(), OE = PN.op_end();
+ for (; OI != OE; ++OI)
+ if (*OI == OldPtr)
+ *OI = NewPtr;
+
+ DEBUG(dbgs() << " to: " << PN << "\n");
+ deleteIfTriviallyDead(OldPtr);
+ return false;
+ }
+ assert(!Loads.empty());
+
+ Type *LoadTy = cast<PointerType>(PN.getType())->getElementType();
+ IRBuilder<> PHIBuilder(&PN);
+ PHINode *NewPN = PHIBuilder.CreatePHI(LoadTy, PN.getNumIncomingValues());
+ NewPN->takeName(&PN);
+
+ // Get the TBAA tag and alignment to use from one of the loads. It doesn't
+ // matter which one we get and if any differ, it doesn't matter.
+ LoadInst *SomeLoad = cast<LoadInst>(Loads.back());
+ MDNode *TBAATag = SomeLoad->getMetadata(LLVMContext::MD_tbaa);
+ unsigned Align = SomeLoad->getAlignment();
+ Value *NewPtr = getAdjustedAllocaPtr(PtrBuilder, OldPtr->getType());
+
+ // Rewrite all loads of the PN to use the new PHI.
+ do {
+ LoadInst *LI = Loads.pop_back_val();
+ LI->replaceAllUsesWith(NewPN);
+ Pass.DeadInsts.push_back(LI);
+ } while (!Loads.empty());
+
+ // Inject loads into all of the pred blocks.
+ for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
+ BasicBlock *Pred = PN.getIncomingBlock(Idx);
+ TerminatorInst *TI = Pred->getTerminator();
+ Value *InVal = PN.getIncomingValue(Idx);
+ IRBuilder<> PredBuilder(TI);
+
+ // Map the value to the new alloca pointer if this was the old alloca
+ // pointer.
+ bool ThisOperand = InVal == OldPtr;
+ if (ThisOperand)
+ InVal = NewPtr;
+
+ LoadInst *Load
+ = PredBuilder.CreateLoad(InVal, getName(".sroa.speculate." +
+ Pred->getName()));
+ ++NumLoadsSpeculated;
+ Load->setAlignment(Align);
+ if (TBAATag)
+ Load->setMetadata(LLVMContext::MD_tbaa, TBAATag);
+ NewPN->addIncoming(Load, Pred);
+
+ if (ThisOperand)
+ continue;
+ Instruction *OtherPtr = dyn_cast<Instruction>(InVal);
+ if (!OtherPtr)
+ // No uses to rewrite.
+ continue;
+
+ // Try to lookup and rewrite any partition uses corresponding to this phi
+ // input.
+ AllocaPartitioning::iterator PI
+ = P.findPartitionForPHIOrSelectOperand(PN, OtherPtr);
+ if (PI != P.end()) {
+ // If the other pointer is within the partitioning, replace the PHI in
+ // its uses with the load we just speculated, or add another load for
+ // it to rewrite if we've already replaced the PHI.
+ AllocaPartitioning::use_iterator UI
+ = P.findPartitionUseForPHIOrSelectOperand(PN, OtherPtr);
+ if (isa<PHINode>(*UI->User))
+ UI->User = Load;
+ else {
+ AllocaPartitioning::PartitionUse OtherUse = *UI;
+ OtherUse.User = Load;
+ P.use_insert(PI, std::upper_bound(UI, P.use_end(PI), OtherUse),
+ OtherUse);
+ }
+ }
+ }
+ DEBUG(dbgs() << " speculated to: " << *NewPN << "\n");
+ return NewPtr == &NewAI;
+ }
+
+ /// Select instructions that use an alloca and are subsequently loaded can be
+ /// rewritten to load both input pointers and then select between the result,
+ /// allowing the load of the alloca to be promoted.
+ /// From this:
+ /// %P2 = select i1 %cond, i32* %Alloca, i32* %Other
+ /// %V = load i32* %P2
+ /// to:
+ /// %V1 = load i32* %Alloca -> will be mem2reg'd
+ /// %V2 = load i32* %Other
+ /// %V = select i1 %cond, i32 %V1, i32 %V2
+ ///
+ /// We can do this to a select if its only uses are loads and if the operand
+ /// to the select can be loaded unconditionally.
+ bool isSafeSelectToSpeculate(SelectInst &SI,
+ SmallVectorImpl<LoadInst *> &Loads) {
+ Value *TValue = SI.getTrueValue();
+ Value *FValue = SI.getFalseValue();
+ bool TDerefable = TValue->isDereferenceablePointer();
+ bool FDerefable = FValue->isDereferenceablePointer();
+
+ for (Value::use_iterator UI = SI.use_begin(), UE = SI.use_end();
+ UI != UE; ++UI) {
+ LoadInst *LI = dyn_cast<LoadInst>(*UI);
+ if (LI == 0 || !LI->isSimple()) return false;
+
+ // Both operands to the select need to be dereferencable, either
+ // absolutely (e.g. allocas) or at this point because we can see other
+ // accesses to it.
+ if (!TDerefable && !isSafeToLoadUnconditionally(TValue, LI,
+ LI->getAlignment(), &TD))
+ return false;
+ if (!FDerefable && !isSafeToLoadUnconditionally(FValue, LI,
+ LI->getAlignment(), &TD))
+ return false;
+ Loads.push_back(LI);
+ }
+
+ return true;
+ }
+
+ bool visitSelectInst(SelectInst &SI) {
+ DEBUG(dbgs() << " original: " << SI << "\n");
+ IRBuilder<> IRB(&SI);
+
+ // Find the operand we need to rewrite here.
+ bool IsTrueVal = SI.getTrueValue() == OldPtr;
+ if (IsTrueVal)
+ assert(SI.getFalseValue() != OldPtr && "Pointer is both operands!");
+ else
+ assert(SI.getFalseValue() == OldPtr && "Pointer isn't an operand!");
+ Value *NewPtr = getAdjustedAllocaPtr(IRB, OldPtr->getType());
+
+ // If the select isn't safe to speculate, just use simple logic to emit it.
+ SmallVector<LoadInst *, 4> Loads;
+ if (!isSafeSelectToSpeculate(SI, Loads)) {
+ SI.setOperand(IsTrueVal ? 1 : 2, NewPtr);
+ DEBUG(dbgs() << " to: " << SI << "\n");
+ deleteIfTriviallyDead(OldPtr);
+ return false;
+ }
+
+ Value *OtherPtr = IsTrueVal ? SI.getFalseValue() : SI.getTrueValue();
+ AllocaPartitioning::iterator PI
+ = P.findPartitionForPHIOrSelectOperand(SI, OtherPtr);
+ AllocaPartitioning::PartitionUse OtherUse;
+ if (PI != P.end()) {
+ // If the other pointer is within the partitioning, remove the select
+ // from its uses. We'll add in the new loads below.
+ AllocaPartitioning::use_iterator UI
+ = P.findPartitionUseForPHIOrSelectOperand(SI, OtherPtr);
+ OtherUse = *UI;
+ P.use_erase(PI, UI);
+ }
+
+ Value *TV = IsTrueVal ? NewPtr : SI.getTrueValue();
+ Value *FV = IsTrueVal ? SI.getFalseValue() : NewPtr;
+ // Replace the loads of the select with a select of two loads.
+ while (!Loads.empty()) {
+ LoadInst *LI = Loads.pop_back_val();
+
+ IRB.SetInsertPoint(LI);
+ LoadInst *TL =
+ IRB.CreateLoad(TV, getName("." + LI->getName() + ".true"));
+ LoadInst *FL =
+ IRB.CreateLoad(FV, getName("." + LI->getName() + ".false"));
+ NumLoadsSpeculated += 2;
+ if (PI != P.end()) {
+ LoadInst *OtherLoad = IsTrueVal ? FL : TL;
+ assert(OtherUse.Ptr == OtherLoad->getOperand(0));
+ OtherUse.User = OtherLoad;
+ P.use_insert(PI, P.use_end(PI), OtherUse);
+ }
+
+ // Transfer alignment and TBAA info if present.
+ TL->setAlignment(LI->getAlignment());
+ FL->setAlignment(LI->getAlignment());
+ if (MDNode *Tag = LI->getMetadata(LLVMContext::MD_tbaa)) {
+ TL->setMetadata(LLVMContext::MD_tbaa, Tag);
+ FL->setMetadata(LLVMContext::MD_tbaa, Tag);
+ }
+
+ Value *V = IRB.CreateSelect(SI.getCondition(), TL, FL);
+ V->takeName(LI);
+ DEBUG(dbgs() << " speculated to: " << *V << "\n");
+ LI->replaceAllUsesWith(V);
+ Pass.DeadInsts.push_back(LI);
+ }
+ if (PI != P.end())
+ std::stable_sort(P.use_begin(PI), P.use_end(PI));
+
+ deleteIfTriviallyDead(OldPtr);
+ return NewPtr == &NewAI;
+ }
+
+};
+}
+
+/// \brief Try to find a partition of the aggregate type passed in for a given
+/// offset and size.
+///
+/// This recurses through the aggregate type and tries to compute a subtype
+/// based on the offset and size. When the offset and size span a sub-section
+/// of an array, it will even compute a new array type for that sub-section.
+static Type *getTypePartition(const TargetData &TD, Type *Ty,
+ uint64_t Offset, uint64_t Size) {
+ if (Offset == 0 && TD.getTypeAllocSize(Ty) == Size)
+ return Ty;
+
+ if (SequentialType *SeqTy = dyn_cast<SequentialType>(Ty)) {
+ // We can't partition pointers...
+ if (SeqTy->isPointerTy())
+ return 0;
+
+ Type *ElementTy = SeqTy->getElementType();
+ uint64_t ElementSize = TD.getTypeAllocSize(ElementTy);
+ uint64_t NumSkippedElements = Offset / ElementSize;
+ if (ArrayType *ArrTy = dyn_cast<ArrayType>(SeqTy))
+ if (NumSkippedElements >= ArrTy->getNumElements())
+ return 0;
+ if (VectorType *VecTy = dyn_cast<VectorType>(SeqTy))
+ if (NumSkippedElements >= VecTy->getNumElements())
+ return 0;
+ Offset -= NumSkippedElements * ElementSize;
+
+ // First check if we need to recurse.
+ if (Offset > 0 || Size < ElementSize) {
+ // Bail if the partition ends in a different array element.
+ if ((Offset + Size) > ElementSize)
+ return 0;
+ // Recurse through the element type trying to peel off offset bytes.
+ return getTypePartition(TD, ElementTy, Offset, Size);
+ }
+ assert(Offset == 0);
+
+ if (Size == ElementSize)
+ return ElementTy;
+ assert(Size > ElementSize);
+ uint64_t NumElements = Size / ElementSize;
+ if (NumElements * ElementSize != Size)
+ return 0;
+ return ArrayType::get(ElementTy, NumElements);
+ }
+
+ StructType *STy = dyn_cast<StructType>(Ty);
+ if (!STy)
+ return 0;
+
+ const StructLayout *SL = TD.getStructLayout(STy);
+ if (Offset > SL->getSizeInBytes())
+ return 0;
+ uint64_t EndOffset = Offset + Size;
+ if (EndOffset > SL->getSizeInBytes())
+ return 0;
+
+ unsigned Index = SL->getElementContainingOffset(Offset);
+ if (SL->getElementOffset(Index) != Offset)
+ return 0; // Inside of padding.
+ Offset -= SL->getElementOffset(Index);
+
+ Type *ElementTy = STy->getElementType(Index);
+ uint64_t ElementSize = TD.getTypeAllocSize(ElementTy);
+ if (Offset >= ElementSize)
+ return 0; // The offset points into alignment padding.
+
+ // See if any partition must be contained by the element.
+ if (Offset > 0 || Size < ElementSize) {
+ if ((Offset + Size) > ElementSize)
+ return 0;
+ // Bail if this is a poniter element, we can't recurse through them.
+ if (ElementTy->isPointerTy())
+ return 0;
+ return getTypePartition(TD, ElementTy, Offset, Size);
+ }
+ assert(Offset == 0);
+
+ if (Size == ElementSize)
+ return ElementTy;
+
+ StructType::element_iterator EI = STy->element_begin() + Index,
+ EE = STy->element_end();
+ if (EndOffset < SL->getSizeInBytes()) {
+ unsigned EndIndex = SL->getElementContainingOffset(EndOffset);
+ if (Index == EndIndex)
+ return 0; // Within a single element and its padding.
+ assert(Index < EndIndex);
+ assert(Index + EndIndex <= STy->getNumElements());
+ EE = STy->element_begin() + EndIndex;
+ }
+
+ // Try to build up a sub-structure.
+ SmallVector<Type *, 4> ElementTys;
+ do {
+ ElementTys.push_back(*EI++);
+ } while (EI != EE);
+ StructType *SubTy = StructType::get(STy->getContext(), ElementTys,
+ STy->isPacked());
+ const StructLayout *SubSL = TD.getStructLayout(SubTy);
+ if (Size == SubSL->getSizeInBytes())
+ return SubTy;
+
+ // FIXME: We could potentially recurse down through the last element in the
+ // sub-struct to find a natural end point.
+ return 0;
+}
+
+/// \brief Rewrite an alloca partition's users.
+///
+/// This routine drives both of the rewriting goals of the SROA pass. It tries
+/// to rewrite uses of an alloca partition to be conducive for SSA value
+/// promotion. If the partition needs a new, more refined alloca, this will
+/// build that new alloca, preserving as much type information as possible, and
+/// rewrite the uses of the old alloca to point at the new one and have the
+/// appropriate new offsets. It also evaluates how successful the rewrite was
+/// at enabling promotion and if it was successful queues the alloca to be
+/// promoted.
+bool SROA::rewriteAllocaPartition(AllocaInst &AI,
+ AllocaPartitioning &P,
+ AllocaPartitioning::iterator PI) {
+ uint64_t AllocaSize = PI->EndOffset - PI->BeginOffset;
+ if (P.use_begin(PI) == P.use_end(PI))
+ return false; // No live uses left of this partition.
+
+ // Try to compute a friendly type for this partition of the alloca. This
+ // won't always succeed, in which case we fall back to a legal integer type
+ // or an i8 array of an appropriate size.
+ Type *AllocaTy = 0;
+ if (Type *PartitionTy = P.getCommonType(PI))
+ if (TD->getTypeAllocSize(PartitionTy) >= AllocaSize)
+ AllocaTy = PartitionTy;
+ if (!AllocaTy)
+ if (Type *PartitionTy = getTypePartition(*TD, AI.getAllocatedType(),
+ PI->BeginOffset, AllocaSize))
+ AllocaTy = PartitionTy;
+ if ((!AllocaTy ||
+ (AllocaTy->isArrayTy() &&
+ AllocaTy->getArrayElementType()->isIntegerTy())) &&
+ TD->isLegalInteger(AllocaSize * 8))
+ AllocaTy = Type::getIntNTy(*C, AllocaSize * 8);
+ if (!AllocaTy)
+ AllocaTy = ArrayType::get(Type::getInt8Ty(*C), AllocaSize);
+
+ // Check for the case where we're going to rewrite to a new alloca of the
+ // exact same type as the original, and with the same access offsets. In that
+ // case, re-use the existing alloca, but still run through the rewriter to
+ // performe phi and select speculation.
+ AllocaInst *NewAI;
+ if (AllocaTy == AI.getAllocatedType()) {
+ assert(PI->BeginOffset == 0 &&
+ "Non-zero begin offset but same alloca type");
+ assert(PI == P.begin() && "Begin offset is zero on later partition");
+ NewAI = &AI;
+ } else {
+ // FIXME: The alignment here is overly conservative -- we could in many
+ // cases get away with much weaker alignment constraints.
+ NewAI = new AllocaInst(AllocaTy, 0, AI.getAlignment(),
+ AI.getName() + ".sroa." + Twine(PI - P.begin()),
+ &AI);
+ ++NumNewAllocas;
+ }
+
+ DEBUG(dbgs() << "Rewriting alloca partition "
+ << "[" << PI->BeginOffset << "," << PI->EndOffset << ") to: "
+ << *NewAI << "\n");
+
+ AllocaPartitionRewriter Rewriter(*TD, P, PI, *this, AI, *NewAI,
+ PI->BeginOffset, PI->EndOffset);
+ DEBUG(dbgs() << " rewriting ");
+ DEBUG(P.print(dbgs(), PI, ""));
+ if (Rewriter.visitUsers(P.use_begin(PI), P.use_end(PI))) {
+ DEBUG(dbgs() << " and queuing for promotion\n");
+ PromotableAllocas.push_back(NewAI);
+ } else if (NewAI != &AI) {
+ // If we can't promote the alloca, iterate on it to check for new
+ // refinements exposed by splitting the current alloca. Don't iterate on an
+ // alloca which didn't actually change and didn't get promoted.
+ Worklist.insert(NewAI);
+ }
+ return true;
+}
+
+/// \brief Walks the partitioning of an alloca rewriting uses of each partition.
+bool SROA::splitAlloca(AllocaInst &AI, AllocaPartitioning &P) {
+ bool Changed = false;
+ for (AllocaPartitioning::iterator PI = P.begin(), PE = P.end(); PI != PE;
+ ++PI)
+ Changed |= rewriteAllocaPartition(AI, P, PI);
+
+ return Changed;
+}
+
+/// \brief Analyze an alloca for SROA.
+///
+/// This analyzes the alloca to ensure we can reason about it, builds
+/// a partitioning of the alloca, and then hands it off to be split and
+/// rewritten as needed.
+bool SROA::runOnAlloca(AllocaInst &AI) {
+ DEBUG(dbgs() << "SROA alloca: " << AI << "\n");
+ ++NumAllocasAnalyzed;
+
+ // Special case dead allocas, as they're trivial.
+ if (AI.use_empty()) {
+ AI.eraseFromParent();
+ return true;
+ }
+
+ // Skip alloca forms that this analysis can't handle.
+ if (AI.isArrayAllocation() || !AI.getAllocatedType()->isSized() ||
+ TD->getTypeAllocSize(AI.getAllocatedType()) == 0)
+ return false;
+
+ // First check if this is a non-aggregate type that we should simply promote.
+ if (!AI.getAllocatedType()->isAggregateType() && isAllocaPromotable(&AI)) {
+ DEBUG(dbgs() << " Trivially scalar type, queuing for promotion...\n");
+ PromotableAllocas.push_back(&AI);
+ return false;
+ }
+
+ // Build the partition set using a recursive instruction-visiting builder.
+ AllocaPartitioning P(*TD, AI);
+ DEBUG(P.print(dbgs()));
+ if (P.isEscaped())
+ return false;
+
+ // No partitions to split. Leave the dead alloca for a later pass to clean up.
+ if (P.begin() == P.end())
+ return false;
+
+ // Delete all the dead users of this alloca before splitting and rewriting it.
+ bool Changed = false;
+ for (AllocaPartitioning::dead_user_iterator DI = P.dead_user_begin(),
+ DE = P.dead_user_end();
+ DI != DE; ++DI) {
+ Changed = true;
+ (*DI)->replaceAllUsesWith(UndefValue::get((*DI)->getType()));
+ DeadInsts.push_back(*DI);
+ }
+ for (AllocaPartitioning::dead_op_iterator DO = P.dead_op_begin(),
+ DE = P.dead_op_end();
+ DO != DE; ++DO) {
+ Value *OldV = **DO;
+ // Clobber the use with an undef value.
+ **DO = UndefValue::get(OldV->getType());
+ if (Instruction *OldI = dyn_cast<Instruction>(OldV))
+ if (isInstructionTriviallyDead(OldI)) {
+ Changed = true;
+ DeadInsts.push_back(OldI);
+ }
+ }
+
+ return splitAlloca(AI, P) || Changed;
+}
+
+void SROA::deleteDeadInstructions() {
+ DeadSplitInsts.clear();
+ while (!DeadInsts.empty()) {
+ Instruction *I = DeadInsts.pop_back_val();
+ DEBUG(dbgs() << "Deleting dead instruction: " << *I << "\n");
+
+ for (User::op_iterator OI = I->op_begin(), E = I->op_end(); OI != E; ++OI)
+ if (Instruction *U = dyn_cast<Instruction>(*OI)) {
+ // Zero out the operand and see if it becomes trivially dead.
+ *OI = 0;
+ if (isInstructionTriviallyDead(U))
+ DeadInsts.push_back(U);
+ }
+
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
+ DeletedAllocas.insert(AI);
+
+ ++NumDeleted;
+ I->eraseFromParent();
+ }
+}
+
+namespace {
+ /// \brief A predicate to test whether an alloca belongs to a set.
+ class IsAllocaInSet {
+ typedef SmallPtrSet<AllocaInst *, 4> SetType;
+ const SetType &Set;
+
+ public:
+ IsAllocaInSet(const SetType &Set) : Set(Set) {}
+ bool operator()(AllocaInst *AI) { return Set.count(AI); }
+ };
+}
+
+bool SROA::runOnFunction(Function &F) {
+ DEBUG(dbgs() << "SROA function: " << F.getName() << "\n");
+ C = &F.getContext();
+ TD = getAnalysisIfAvailable<TargetData>();
+ if (!TD) {
+ DEBUG(dbgs() << " Skipping SROA -- no target data!\n");
+ return false;
+ }
+ DT = &getAnalysis<DominatorTree>();
+
+ BasicBlock &EntryBB = F.getEntryBlock();
+ for (BasicBlock::iterator I = EntryBB.begin(), E = llvm::prior(EntryBB.end());
+ I != E; ++I)
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
+ Worklist.insert(AI);
+
+ bool Changed = false;
+ while (!Worklist.empty()) {
+ Changed |= runOnAlloca(*Worklist.pop_back_val());
+ deleteDeadInstructions();
+ if (!DeletedAllocas.empty()) {
+ PromotableAllocas.erase(std::remove_if(PromotableAllocas.begin(),
+ PromotableAllocas.end(),
+ IsAllocaInSet(DeletedAllocas)),
+ PromotableAllocas.end());
+ DeletedAllocas.clear();
+ }
+ }
+
+ if (!PromotableAllocas.empty()) {
+ DEBUG(dbgs() << "Promoting allocas with mem2reg...\n");
+ PromoteMemToReg(PromotableAllocas, *DT);
+ Changed = true;
+ NumPromoted += PromotableAllocas.size();
+ PromotableAllocas.clear();
+ }
+
+ return Changed;
+}
+
+void SROA::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<DominatorTree>();
+ AU.setPreservesCFG();
+}
--- /dev/null
+; RUN: opt < %s -sroa -S | FileCheck %s
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n8:16:32:64"
+
+define i32 @test0() {
+; CHECK: @test0
+; CHECK-NOT: alloca
+; CHECK: ret i32
+
+entry:
+ %a1 = alloca i32
+ %a2 = alloca float
+
+ store i32 0, i32* %a1
+ %v1 = load i32* %a1
+
+ store float 0.0, float* %a2
+ %v2 = load float * %a2
+ %v2.int = bitcast float %v2 to i32
+ %sum1 = add i32 %v1, %v2.int
+
+ ret i32 %sum1
+}
+
+define i32 @test1() {
+; CHECK: @test1
+; CHECK-NOT: alloca
+; CHECK: ret i32 0
+
+entry:
+ %X = alloca { i32, float }
+ %Y = getelementptr { i32, float }* %X, i64 0, i32 0
+ store i32 0, i32* %Y
+ %Z = load i32* %Y
+ ret i32 %Z
+}
+
+define i64 @test2(i64 %X) {
+; CHECK: @test2
+; CHECK-NOT: alloca
+; CHECK: ret i64 %X
+
+entry:
+ %A = alloca [8 x i8]
+ %B = bitcast [8 x i8]* %A to i64*
+ store i64 %X, i64* %B
+ br label %L2
+
+L2:
+ %Z = load i64* %B
+ ret i64 %Z
+}
+
+define void @test3(i8* %dst, i8* %src) {
+; CHECK: @test3
+
+entry:
+ %a = alloca [300 x i8]
+; CHECK-NOT: alloca
+; CHECK: %[[test3_a1:.*]] = alloca [42 x i8]
+; CHECK-NEXT: %[[test3_a2:.*]] = alloca [99 x i8]
+; CHECK-NEXT: %[[test3_a3:.*]] = alloca [16 x i8]
+; CHECK-NEXT: %[[test3_a4:.*]] = alloca [42 x i8]
+; CHECK-NEXT: %[[test3_a5:.*]] = alloca [7 x i8]
+; CHECK-NEXT: %[[test3_a6:.*]] = alloca [7 x i8]
+; CHECK-NEXT: %[[test3_a7:.*]] = alloca [85 x i8]
+
+ %b = getelementptr [300 x i8]* %a, i64 0, i64 0
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %b, i8* %src, i32 300, i32 1, i1 false)
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [42 x i8]* %[[test3_a1]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %src, i32 42
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 42
+; CHECK-NEXT: %[[test3_r1:.*]] = load i8* %[[gep]]
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 43
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [99 x i8]* %[[test3_a2]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 99
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 142
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 16
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 158
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [42 x i8]* %[[test3_a4]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 42
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 200
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 207
+; CHECK-NEXT: %[[test3_r2:.*]] = load i8* %[[gep]]
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 208
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 215
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [85 x i8]* %[[test3_a7]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 85
+
+ ; Clobber a single element of the array, this should be promotable.
+ %c = getelementptr [300 x i8]* %a, i64 0, i64 42
+ store i8 0, i8* %c
+
+ ; Make a sequence of overlapping stores to the array. These overlap both in
+ ; forward strides and in shrinking accesses.
+ %overlap.1.i8 = getelementptr [300 x i8]* %a, i64 0, i64 142
+ %overlap.2.i8 = getelementptr [300 x i8]* %a, i64 0, i64 143
+ %overlap.3.i8 = getelementptr [300 x i8]* %a, i64 0, i64 144
+ %overlap.4.i8 = getelementptr [300 x i8]* %a, i64 0, i64 145
+ %overlap.5.i8 = getelementptr [300 x i8]* %a, i64 0, i64 146
+ %overlap.6.i8 = getelementptr [300 x i8]* %a, i64 0, i64 147
+ %overlap.7.i8 = getelementptr [300 x i8]* %a, i64 0, i64 148
+ %overlap.8.i8 = getelementptr [300 x i8]* %a, i64 0, i64 149
+ %overlap.9.i8 = getelementptr [300 x i8]* %a, i64 0, i64 150
+ %overlap.1.i16 = bitcast i8* %overlap.1.i8 to i16*
+ %overlap.1.i32 = bitcast i8* %overlap.1.i8 to i32*
+ %overlap.1.i64 = bitcast i8* %overlap.1.i8 to i64*
+ %overlap.2.i64 = bitcast i8* %overlap.2.i8 to i64*
+ %overlap.3.i64 = bitcast i8* %overlap.3.i8 to i64*
+ %overlap.4.i64 = bitcast i8* %overlap.4.i8 to i64*
+ %overlap.5.i64 = bitcast i8* %overlap.5.i8 to i64*
+ %overlap.6.i64 = bitcast i8* %overlap.6.i8 to i64*
+ %overlap.7.i64 = bitcast i8* %overlap.7.i8 to i64*
+ %overlap.8.i64 = bitcast i8* %overlap.8.i8 to i64*
+ %overlap.9.i64 = bitcast i8* %overlap.9.i8 to i64*
+ store i8 1, i8* %overlap.1.i8
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 0
+; CHECK-NEXT: store i8 1, i8* %[[gep]]
+ store i16 1, i16* %overlap.1.i16
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast [16 x i8]* %[[test3_a3]] to i16*
+; CHECK-NEXT: store i16 1, i16* %[[bitcast]]
+ store i32 1, i32* %overlap.1.i32
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast [16 x i8]* %[[test3_a3]] to i32*
+; CHECK-NEXT: store i32 1, i32* %[[bitcast]]
+ store i64 1, i64* %overlap.1.i64
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast [16 x i8]* %[[test3_a3]] to i64*
+; CHECK-NEXT: store i64 1, i64* %[[bitcast]]
+ store i64 2, i64* %overlap.2.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 1
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 2, i64* %[[bitcast]]
+ store i64 3, i64* %overlap.3.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 2
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 3, i64* %[[bitcast]]
+ store i64 4, i64* %overlap.4.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 3
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 4, i64* %[[bitcast]]
+ store i64 5, i64* %overlap.5.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 4
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 5, i64* %[[bitcast]]
+ store i64 6, i64* %overlap.6.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 5
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 6, i64* %[[bitcast]]
+ store i64 7, i64* %overlap.7.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 6
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 7, i64* %[[bitcast]]
+ store i64 8, i64* %overlap.8.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 7
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 8, i64* %[[bitcast]]
+ store i64 9, i64* %overlap.9.i64
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 8
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i64*
+; CHECK-NEXT: store i64 9, i64* %[[bitcast]]
+
+ ; Make two sequences of overlapping stores with more gaps and irregularities.
+ %overlap2.1.0.i8 = getelementptr [300 x i8]* %a, i64 0, i64 200
+ %overlap2.1.1.i8 = getelementptr [300 x i8]* %a, i64 0, i64 201
+ %overlap2.1.2.i8 = getelementptr [300 x i8]* %a, i64 0, i64 202
+ %overlap2.1.3.i8 = getelementptr [300 x i8]* %a, i64 0, i64 203
+
+ %overlap2.2.0.i8 = getelementptr [300 x i8]* %a, i64 0, i64 208
+ %overlap2.2.1.i8 = getelementptr [300 x i8]* %a, i64 0, i64 209
+ %overlap2.2.2.i8 = getelementptr [300 x i8]* %a, i64 0, i64 210
+ %overlap2.2.3.i8 = getelementptr [300 x i8]* %a, i64 0, i64 211
+
+ %overlap2.1.0.i16 = bitcast i8* %overlap2.1.0.i8 to i16*
+ %overlap2.1.0.i32 = bitcast i8* %overlap2.1.0.i8 to i32*
+ %overlap2.1.1.i32 = bitcast i8* %overlap2.1.1.i8 to i32*
+ %overlap2.1.2.i32 = bitcast i8* %overlap2.1.2.i8 to i32*
+ %overlap2.1.3.i32 = bitcast i8* %overlap2.1.3.i8 to i32*
+ store i8 1, i8* %overlap2.1.0.i8
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 0
+; CHECK-NEXT: store i8 1, i8* %[[gep]]
+ store i16 1, i16* %overlap2.1.0.i16
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast [7 x i8]* %[[test3_a5]] to i16*
+; CHECK-NEXT: store i16 1, i16* %[[bitcast]]
+ store i32 1, i32* %overlap2.1.0.i32
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast [7 x i8]* %[[test3_a5]] to i32*
+; CHECK-NEXT: store i32 1, i32* %[[bitcast]]
+ store i32 2, i32* %overlap2.1.1.i32
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 1
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i32*
+; CHECK-NEXT: store i32 2, i32* %[[bitcast]]
+ store i32 3, i32* %overlap2.1.2.i32
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 2
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i32*
+; CHECK-NEXT: store i32 3, i32* %[[bitcast]]
+ store i32 4, i32* %overlap2.1.3.i32
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 3
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i32*
+; CHECK-NEXT: store i32 4, i32* %[[bitcast]]
+
+ %overlap2.2.0.i32 = bitcast i8* %overlap2.2.0.i8 to i32*
+ %overlap2.2.1.i16 = bitcast i8* %overlap2.2.1.i8 to i16*
+ %overlap2.2.1.i32 = bitcast i8* %overlap2.2.1.i8 to i32*
+ %overlap2.2.2.i32 = bitcast i8* %overlap2.2.2.i8 to i32*
+ %overlap2.2.3.i32 = bitcast i8* %overlap2.2.3.i8 to i32*
+ store i32 1, i32* %overlap2.2.0.i32
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast [7 x i8]* %[[test3_a6]] to i32*
+; CHECK-NEXT: store i32 1, i32* %[[bitcast]]
+ store i8 1, i8* %overlap2.2.1.i8
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 1
+; CHECK-NEXT: store i8 1, i8* %[[gep]]
+ store i16 1, i16* %overlap2.2.1.i16
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 1
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i16*
+; CHECK-NEXT: store i16 1, i16* %[[bitcast]]
+ store i32 1, i32* %overlap2.2.1.i32
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 1
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i32*
+; CHECK-NEXT: store i32 1, i32* %[[bitcast]]
+ store i32 3, i32* %overlap2.2.2.i32
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 2
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i32*
+; CHECK-NEXT: store i32 3, i32* %[[bitcast]]
+ store i32 4, i32* %overlap2.2.3.i32
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 3
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i32*
+; CHECK-NEXT: store i32 4, i32* %[[bitcast]]
+
+ %overlap2.prefix = getelementptr i8* %overlap2.1.1.i8, i64 -4
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %overlap2.prefix, i8* %src, i32 8, i32 1, i1 false)
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [42 x i8]* %[[test3_a4]], i64 0, i64 39
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %src, i32 3
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 3
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 5
+
+ ; Bridge between the overlapping areas
+ call void @llvm.memset.p0i8.i32(i8* %overlap2.1.2.i8, i8 42, i32 8, i32 1, i1 false)
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 2
+; CHECK-NEXT: call void @llvm.memset.p0i8.i32(i8* %[[gep]], i8 42, i32 5
+; ...promoted i8 store...
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memset.p0i8.i32(i8* %[[gep]], i8 42, i32 2
+
+ ; Entirely within the second overlap.
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %overlap2.2.1.i8, i8* %src, i32 5, i32 1, i1 false)
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 1
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep]], i8* %src, i32 5
+
+ ; Trailing past the second overlap.
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %overlap2.2.2.i8, i8* %src, i32 8, i32 1, i1 false)
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 2
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep]], i8* %src, i32 5
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 5
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [85 x i8]* %[[test3_a7]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 3
+
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %b, i32 300, i32 1, i1 false)
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [42 x i8]* %[[test3_a1]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %[[gep]], i32 42
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 42
+; CHECK-NEXT: store i8 0, i8* %[[gep]]
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 43
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [99 x i8]* %[[test3_a2]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 99
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 142
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [16 x i8]* %[[test3_a3]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 16
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 158
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [42 x i8]* %[[test3_a4]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 42
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 200
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a5]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 207
+; CHECK-NEXT: store i8 42, i8* %[[gep]]
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 208
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [7 x i8]* %[[test3_a6]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 215
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [85 x i8]* %[[test3_a7]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 85
+
+ ret void
+}
+
+define void @test4(i8* %dst, i8* %src) {
+; CHECK: @test4
+
+entry:
+ %a = alloca [100 x i8]
+; CHECK-NOT: alloca
+; CHECK: %[[test4_a1:.*]] = alloca [20 x i8]
+; CHECK-NEXT: %[[test4_a2:.*]] = alloca [7 x i8]
+; CHECK-NEXT: %[[test4_a3:.*]] = alloca [10 x i8]
+; CHECK-NEXT: %[[test4_a4:.*]] = alloca [7 x i8]
+; CHECK-NEXT: %[[test4_a5:.*]] = alloca [7 x i8]
+; CHECK-NEXT: %[[test4_a6:.*]] = alloca [40 x i8]
+
+ %b = getelementptr [100 x i8]* %a, i64 0, i64 0
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %b, i8* %src, i32 100, i32 1, i1 false)
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [20 x i8]* %[[test4_a1]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep]], i8* %src, i32 20
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 20
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i16*
+; CHECK-NEXT: %[[test4_r1:.*]] = load i16* %[[bitcast]]
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 22
+; CHECK-NEXT: %[[test4_r2:.*]] = load i8* %[[gep]]
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 23
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a2]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 30
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [10 x i8]* %[[test4_a3]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 10
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 40
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i16*
+; CHECK-NEXT: %[[test4_r3:.*]] = load i16* %[[bitcast]]
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 42
+; CHECK-NEXT: %[[test4_r4:.*]] = load i8* %[[gep]]
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 43
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a4]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 50
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i16*
+; CHECK-NEXT: %[[test4_r5:.*]] = load i16* %[[bitcast]]
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %src, i64 52
+; CHECK-NEXT: %[[test4_r6:.*]] = load i8* %[[gep]]
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 53
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a5]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds i8* %src, i64 60
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [40 x i8]* %[[test4_a6]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 40
+
+ %a.src.1 = getelementptr [100 x i8]* %a, i64 0, i64 20
+ %a.dst.1 = getelementptr [100 x i8]* %a, i64 0, i64 40
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a.dst.1, i8* %a.src.1, i32 10, i32 1, i1 false)
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a4]], i64 0, i64 0
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a2]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+
+ ; Clobber a single element of the array, this should be promotable, and be deleted.
+ %c = getelementptr [100 x i8]* %a, i64 0, i64 42
+ store i8 0, i8* %c
+
+ %a.src.2 = getelementptr [100 x i8]* %a, i64 0, i64 50
+ call void @llvm.memmove.p0i8.p0i8.i32(i8* %a.dst.1, i8* %a.src.2, i32 10, i32 1, i1 false)
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a4]], i64 0, i64 0
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a5]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %b, i32 100, i32 1, i1 false)
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds [20 x i8]* %[[test4_a1]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %[[gep]], i32 20
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 20
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i16*
+; CHECK-NEXT: store i16 %[[test4_r1]], i16* %[[bitcast]]
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 22
+; CHECK-NEXT: store i8 %[[test4_r2]], i8* %[[gep]]
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 23
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a2]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 30
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [10 x i8]* %[[test4_a3]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 10
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 40
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i16*
+; CHECK-NEXT: store i16 %[[test4_r5]], i16* %[[bitcast]]
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 42
+; CHECK-NEXT: store i8 %[[test4_r6]], i8* %[[gep]]
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 43
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a4]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 50
+; CHECK-NEXT: %[[bitcast:.*]] = bitcast i8* %[[gep]] to i16*
+; CHECK-NEXT: store i16 %[[test4_r5]], i16* %[[bitcast]]
+; CHECK-NEXT: %[[gep:.*]] = getelementptr inbounds i8* %dst, i64 52
+; CHECK-NEXT: store i8 %[[test4_r6]], i8* %[[gep]]
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 53
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [7 x i8]* %[[test4_a5]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 7
+; CHECK-NEXT: %[[gep_dst:.*]] = getelementptr inbounds i8* %dst, i64 60
+; CHECK-NEXT: %[[gep_src:.*]] = getelementptr inbounds [40 x i8]* %[[test4_a6]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[gep_dst]], i8* %[[gep_src]], i32 40
+
+ ret void
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
+declare void @llvm.memmove.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
+declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind
+
+define i16 @test5() {
+; CHECK: @test5
+; CHECK: alloca float
+; CHECK: ret i16 %
+
+entry:
+ %a = alloca [4 x i8]
+ %fptr = bitcast [4 x i8]* %a to float*
+ store float 0.0, float* %fptr
+ %ptr = getelementptr [4 x i8]* %a, i32 0, i32 2
+ %iptr = bitcast i8* %ptr to i16*
+ %val = load i16* %iptr
+ ret i16 %val
+}
+
+define i32 @test6() {
+; CHECK: @test6
+; CHECK: alloca i32
+; CHECK-NEXT: store volatile i32
+; CHECK-NEXT: load i32*
+; CHECK-NEXT: ret i32
+
+entry:
+ %a = alloca [4 x i8]
+ %ptr = getelementptr [4 x i8]* %a, i32 0, i32 0
+ call void @llvm.memset.p0i8.i32(i8* %ptr, i8 42, i32 4, i32 1, i1 true)
+ %iptr = bitcast i8* %ptr to i32*
+ %val = load i32* %iptr
+ ret i32 %val
+}
+
+define void @test7(i8* %src, i8* %dst) {
+; CHECK: @test7
+; CHECK: alloca i32
+; CHECK-NEXT: bitcast i8* %src to i32*
+; CHECK-NEXT: load volatile i32*
+; CHECK-NEXT: store volatile i32
+; CHECK-NEXT: bitcast i8* %dst to i32*
+; CHECK-NEXT: load volatile i32*
+; CHECK-NEXT: store volatile i32
+; CHECK-NEXT: ret
+
+entry:
+ %a = alloca [4 x i8]
+ %ptr = getelementptr [4 x i8]* %a, i32 0, i32 0
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr, i8* %src, i32 4, i32 1, i1 true)
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %ptr, i32 4, i32 1, i1 true)
+ ret void
+}
+
+
+%S1 = type { i32, i32, [16 x i8] }
+%S2 = type { %S1*, %S2* }
+
+define %S2 @test8(%S2* %s2) {
+; CHECK: @test8
+entry:
+ %new = alloca %S2
+; CHECK-NOT: alloca
+
+ %s2.next.ptr = getelementptr %S2* %s2, i64 0, i32 1
+ %s2.next = load %S2** %s2.next.ptr
+; CHECK: %[[gep:.*]] = getelementptr %S2* %s2, i64 0, i32 1
+; CHECK-NEXT: %[[next:.*]] = load %S2** %[[gep]]
+
+ %s2.next.s1.ptr = getelementptr %S2* %s2.next, i64 0, i32 0
+ %s2.next.s1 = load %S1** %s2.next.s1.ptr
+ %new.s1.ptr = getelementptr %S2* %new, i64 0, i32 0
+ store %S1* %s2.next.s1, %S1** %new.s1.ptr
+ %s2.next.next.ptr = getelementptr %S2* %s2.next, i64 0, i32 1
+ %s2.next.next = load %S2** %s2.next.next.ptr
+ %new.next.ptr = getelementptr %S2* %new, i64 0, i32 1
+ store %S2* %s2.next.next, %S2** %new.next.ptr
+; CHECK-NEXT: %[[gep:.*]] = getelementptr %S2* %[[next]], i64 0, i32 0
+; CHECK-NEXT: %[[next_s1:.*]] = load %S1** %[[gep]]
+; CHECK-NEXT: %[[gep:.*]] = getelementptr %S2* %[[next]], i64 0, i32 1
+; CHECK-NEXT: %[[next_next:.*]] = load %S2** %[[gep]]
+
+ %new.s1 = load %S1** %new.s1.ptr
+ %result1 = insertvalue %S2 undef, %S1* %new.s1, 0
+; CHECK-NEXT: %[[result1:.*]] = insertvalue %S2 undef, %S1* %[[next_s1]], 0
+ %new.next = load %S2** %new.next.ptr
+ %result2 = insertvalue %S2 %result1, %S2* %new.next, 1
+; CHECK-NEXT: %[[result2:.*]] = insertvalue %S2 %[[result1]], %S2* %[[next_next]], 1
+ ret %S2 %result2
+; CHECK-NEXT: ret %S2 %[[result2]]
+}
+
+define i64 @test9() {
+; Ensure we can handle loads off the end of an alloca even when wrapped in
+; weird bit casts and types. The result is undef, but this shouldn't crash
+; anything.
+; CHECK: @test9
+; CHECK-NOT: alloca
+; CHECK: ret i64 undef
+
+entry:
+ %a = alloca { [3 x i8] }
+ %gep1 = getelementptr inbounds { [3 x i8] }* %a, i32 0, i32 0, i32 0
+ store i8 0, i8* %gep1, align 1
+ %gep2 = getelementptr inbounds { [3 x i8] }* %a, i32 0, i32 0, i32 1
+ store i8 0, i8* %gep2, align 1
+ %gep3 = getelementptr inbounds { [3 x i8] }* %a, i32 0, i32 0, i32 2
+ store i8 26, i8* %gep3, align 1
+ %cast = bitcast { [3 x i8] }* %a to { i64 }*
+ %elt = getelementptr inbounds { i64 }* %cast, i32 0, i32 0
+ %result = load i64* %elt
+ ret i64 %result
+}
+
+define %S2* @test10() {
+; CHECK: @test10
+; CHECK-NOT: alloca %S2*
+; CHECK: ret %S2* null
+
+entry:
+ %a = alloca [8 x i8]
+ %ptr = getelementptr [8 x i8]* %a, i32 0, i32 0
+ call void @llvm.memset.p0i8.i32(i8* %ptr, i8 0, i32 8, i32 1, i1 false)
+ %s2ptrptr = bitcast i8* %ptr to %S2**
+ %s2ptr = load %S2** %s2ptrptr
+ ret %S2* %s2ptr
+}
+
+define i32 @test11() {
+; CHECK: @test11
+; CHECK-NOT: alloca
+; CHECK: ret i32 0
+
+entry:
+ %X = alloca i32
+ br i1 undef, label %good, label %bad
+
+good:
+ %Y = getelementptr i32* %X, i64 0
+ store i32 0, i32* %Y
+ %Z = load i32* %Y
+ ret i32 %Z
+
+bad:
+ %Y2 = getelementptr i32* %X, i64 1
+ store i32 0, i32* %Y2
+ %Z2 = load i32* %Y2
+ ret i32 %Z2
+}
+
+define i32 @test12() {
+; CHECK: @test12
+; CHECK: alloca i24
+;
+; FIXME: SROA should promote accesses to this into whole i24 operations instead
+; of i8 operations.
+; CHECK: store i8 0
+; CHECK: store i8 0
+; CHECK: store i8 0
+;
+; CHECK: load i24*
+
+entry:
+ %a = alloca [3 x i8]
+ %b0ptr = getelementptr [3 x i8]* %a, i64 0, i32 0
+ store i8 0, i8* %b0ptr
+ %b1ptr = getelementptr [3 x i8]* %a, i64 0, i32 1
+ store i8 0, i8* %b1ptr
+ %b2ptr = getelementptr [3 x i8]* %a, i64 0, i32 2
+ store i8 0, i8* %b2ptr
+ %iptr = bitcast [3 x i8]* %a to i24*
+ %i = load i24* %iptr
+ %ret = zext i24 %i to i32
+ ret i32 %ret
+}
+
+define i32 @test13() {
+; Ensure we don't crash and handle undefined loads that straddle the end of the
+; allocation.
+; CHECK: @test13
+; CHECK: %[[ret:.*]] = zext i16 undef to i32
+; CHECK: ret i32 %[[ret]]
+
+entry:
+ %a = alloca [3 x i8]
+ %b0ptr = getelementptr [3 x i8]* %a, i64 0, i32 0
+ store i8 0, i8* %b0ptr
+ %b1ptr = getelementptr [3 x i8]* %a, i64 0, i32 1
+ store i8 0, i8* %b1ptr
+ %b2ptr = getelementptr [3 x i8]* %a, i64 0, i32 2
+ store i8 0, i8* %b2ptr
+ %iptrcast = bitcast [3 x i8]* %a to i16*
+ %iptrgep = getelementptr i16* %iptrcast, i64 1
+ %i = load i16* %iptrgep
+ %ret = zext i16 %i to i32
+ ret i32 %ret
+}
+
+%test14.struct = type { [3 x i32] }
+
+define void @test14(...) nounwind uwtable {
+; This is a strange case where we split allocas into promotable partitions, but
+; also gain enough data to prove they must be dead allocas due to GEPs that walk
+; across two adjacent allocas. Test that we don't try to promote or otherwise
+; do bad things to these dead allocas, they should just be removed.
+; CHECK: @test14
+; CHECK-NEXT: entry:
+; CHECK-NEXT: ret void
+
+entry:
+ %a = alloca %test14.struct
+ %p = alloca %test14.struct*
+ %0 = bitcast %test14.struct* %a to i8*
+ %1 = getelementptr i8* %0, i64 12
+ %2 = bitcast i8* %1 to %test14.struct*
+ %3 = getelementptr inbounds %test14.struct* %2, i32 0, i32 0
+ %4 = getelementptr inbounds %test14.struct* %a, i32 0, i32 0
+ %5 = bitcast [3 x i32]* %3 to i32*
+ %6 = bitcast [3 x i32]* %4 to i32*
+ %7 = load i32* %6, align 4
+ store i32 %7, i32* %5, align 4
+ %8 = getelementptr inbounds i32* %5, i32 1
+ %9 = getelementptr inbounds i32* %6, i32 1
+ %10 = load i32* %9, align 4
+ store i32 %10, i32* %8, align 4
+ %11 = getelementptr inbounds i32* %5, i32 2
+ %12 = getelementptr inbounds i32* %6, i32 2
+ %13 = load i32* %12, align 4
+ store i32 %13, i32* %11, align 4
+ ret void
+}
+
+define i32 @test15(i1 %flag) nounwind uwtable {
+; Ensure that when there are dead instructions using an alloca that are not
+; loads or stores we still delete them during partitioning and rewriting.
+; Otherwise we'll go to promote them while thy still have unpromotable uses.
+; CHECK: @test15
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label %loop
+; CHECK: loop:
+; CHECK-NEXT: br label %loop
+
+entry:
+ %l0 = alloca i64
+ %l1 = alloca i64
+ %l2 = alloca i64
+ %l3 = alloca i64
+ br label %loop
+
+loop:
+ %dead3 = phi i8* [ %gep3, %loop ], [ null, %entry ]
+
+ store i64 1879048192, i64* %l0, align 8
+ %bc0 = bitcast i64* %l0 to i8*
+ %gep0 = getelementptr i8* %bc0, i64 3
+ %dead0 = bitcast i8* %gep0 to i64*
+
+ store i64 1879048192, i64* %l1, align 8
+ %bc1 = bitcast i64* %l1 to i8*
+ %gep1 = getelementptr i8* %bc1, i64 3
+ %dead1 = getelementptr i8* %gep1, i64 1
+
+ store i64 1879048192, i64* %l2, align 8
+ %bc2 = bitcast i64* %l2 to i8*
+ %gep2.1 = getelementptr i8* %bc2, i64 1
+ %gep2.2 = getelementptr i8* %bc2, i64 3
+ ; Note that this select should get visited multiple times due to using two
+ ; different GEPs off the same alloca. We should only delete it once.
+ %dead2 = select i1 %flag, i8* %gep2.1, i8* %gep2.2
+
+ store i64 1879048192, i64* %l3, align 8
+ %bc3 = bitcast i64* %l3 to i8*
+ %gep3 = getelementptr i8* %bc3, i64 3
+
+ br label %loop
+}
+
+define void @test16(i8* %src, i8* %dst) {
+; Ensure that we can promote an alloca of [3 x i8] to an i24 SSA value.
+; CHECK: @test16
+; CHECK-NOT: alloca
+; CHECK: %[[srccast:.*]] = bitcast i8* %src to i24*
+; CHECK-NEXT: load i24* %[[srccast]]
+; CHECK-NEXT: %[[dstcast:.*]] = bitcast i8* %dst to i24*
+; CHECK-NEXT: store i24 0, i24* %[[dstcast]]
+; CHECK-NEXT: ret void
+
+entry:
+ %a = alloca [3 x i8]
+ %ptr = getelementptr [3 x i8]* %a, i32 0, i32 0
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr, i8* %src, i32 4, i32 1, i1 false)
+ %cast = bitcast i8* %ptr to i24*
+ store i24 0, i24* %cast
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %ptr, i32 4, i32 1, i1 false)
+ ret void
+}
+
+define void @test17(i8* %src, i8* %dst) {
+; Ensure that we can rewrite unpromotable memcpys which extend past the end of
+; the alloca.
+; CHECK: @test17
+; CHECK: %[[a:.*]] = alloca [3 x i8]
+; CHECK-NEXT: %[[ptr:.*]] = getelementptr [3 x i8]* %[[a]], i32 0, i32 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[ptr]], i8* %src,
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %[[ptr]],
+; CHECK-NEXT: ret void
+
+entry:
+ %a = alloca [3 x i8]
+ %ptr = getelementptr [3 x i8]* %a, i32 0, i32 0
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr, i8* %src, i32 4, i32 1, i1 true)
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %ptr, i32 4, i32 1, i1 true)
+ ret void
+}
+
+define void @test18(i8* %src, i8* %dst, i32 %size) {
+; Preserve transfer instrinsics with a variable size, even if they overlap with
+; fixed size operations. Further, continue to split and promote allocas preceding
+; the variable sized intrinsic.
+; CHECK: @test18
+; CHECK: %[[a:.*]] = alloca [34 x i8]
+; CHECK: %[[srcgep1:.*]] = getelementptr inbounds i8* %src, i64 4
+; CHECK-NEXT: %[[srccast1:.*]] = bitcast i8* %[[srcgep1]] to i32*
+; CHECK-NEXT: %[[srcload:.*]] = load i32* %[[srccast1]]
+; CHECK-NEXT: %[[agep1:.*]] = getelementptr inbounds [34 x i8]* %[[a]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %[[agep1]], i8* %src, i32 %size,
+; CHECK-NEXT: %[[agep2:.*]] = getelementptr inbounds [34 x i8]* %[[a]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memset.p0i8.i32(i8* %[[agep2]], i8 42, i32 %size,
+; CHECK-NEXT: %[[dstcast1:.*]] = bitcast i8* %dst to i32*
+; CHECK-NEXT: store i32 42, i32* %[[dstcast1]]
+; CHECK-NEXT: %[[dstgep1:.*]] = getelementptr inbounds i8* %dst, i64 4
+; CHECK-NEXT: %[[dstcast2:.*]] = bitcast i8* %[[dstgep1]] to i32*
+; CHECK-NEXT: store i32 %[[srcload]], i32* %[[dstcast2]]
+; CHECK-NEXT: %[[agep3:.*]] = getelementptr inbounds [34 x i8]* %[[a]], i64 0, i64 0
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %[[agep3]], i32 %size,
+; CHECK-NEXT: ret void
+
+entry:
+ %a = alloca [42 x i8]
+ %ptr = getelementptr [42 x i8]* %a, i32 0, i32 0
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr, i8* %src, i32 8, i32 1, i1 false)
+ %ptr2 = getelementptr [42 x i8]* %a, i32 0, i32 8
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr2, i8* %src, i32 %size, i32 1, i1 false)
+ call void @llvm.memset.p0i8.i32(i8* %ptr2, i8 42, i32 %size, i32 1, i1 false)
+ %cast = bitcast i8* %ptr to i32*
+ store i32 42, i32* %cast
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %ptr, i32 8, i32 1, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %ptr2, i32 %size, i32 1, i1 false)
+ ret void
+}
+
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