index 01320e22a3d5f3a7c6942b229d061d9f0de2e61e..d0c6bd056352210144b77ffed025c26814598f4c 100644 (file)
///
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "sroa"
#include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/PtrUseVisitor.h"
#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/DIBuilder.h"
-#include "llvm/DebugInfo.h"
#include "llvm/IR/Constants.h"
+#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstVisitor.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Operator.h"
-#include "llvm/InstVisitor.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
using namespace llvm;
+#define DEBUG_TYPE "sroa"
+
STATISTIC(NumAllocasAnalyzed, "Number of allocas analyzed for replacement");
STATISTIC(NumAllocaPartitions, "Number of alloca partitions formed");
STATISTIC(MaxPartitionsPerAlloca, "Maximum number of partitions per alloca");
/// Hidden option to force the pass to not use DomTree and mem2reg, instead
/// forming SSA values through the SSAUpdater infrastructure.
-static cl::opt<bool>
-ForceSSAUpdater("force-ssa-updater", cl::init(false), cl::Hidden);
+static cl::opt<bool> ForceSSAUpdater("force-ssa-updater", cl::init(false),
+ cl::Hidden);
/// Hidden option to enable randomly shuffling the slices to help uncover
/// instability in their order.
/// Hidden option to experiment with completely strict handling of inbounds
/// GEPs.
-static cl::opt<bool> SROAStrictInbounds("sroa-strict-inbounds",
- cl::init(false), cl::Hidden);
+static cl::opt<bool> SROAStrictInbounds("sroa-strict-inbounds", cl::init(false),
+ cl::Hidden);
namespace {
/// \brief A custom IRBuilder inserter which prefixes all names if they are
/// preserved.
template <bool preserveNames = true>
-class IRBuilderPrefixedInserter :
- public IRBuilderDefaultInserter<preserveNames> {
+class IRBuilderPrefixedInserter
+ : public IRBuilderDefaultInserter<preserveNames> {
std::string Prefix;
public:
// Specialization for not preserving the name is trivial.
template <>
-class IRBuilderPrefixedInserter<false> :
- public IRBuilderDefaultInserter<false> {
+class IRBuilderPrefixedInserter<false>
+ : public IRBuilderDefaultInserter<false> {
public:
void SetNamePrefix(const Twine &P) {}
};
/// \brief Provide a typedef for IRBuilder that drops names in release builds.
#ifndef NDEBUG
-typedef llvm::IRBuilder<true, ConstantFolder,
- IRBuilderPrefixedInserter<true> > IRBuilderTy;
+typedef llvm::IRBuilder<true, ConstantFolder, IRBuilderPrefixedInserter<true>>
+ IRBuilderTy;
#else
-typedef llvm::IRBuilder<false, ConstantFolder,
- IRBuilderPrefixedInserter<false> > IRBuilderTy;
+typedef llvm::IRBuilder<false, ConstantFolder, IRBuilderPrefixedInserter<false>>
+ IRBuilderTy;
#endif
}
Use *getUse() const { return UseAndIsSplittable.getPointer(); }
- bool isDead() const { return getUse() == 0; }
- void kill() { UseAndIsSplittable.setPointer(0); }
+ bool isDead() const { return getUse() == nullptr; }
+ void kill() { UseAndIsSplittable.setPointer(nullptr); }
/// \brief Support for ordering ranges.
///
/// decreasing. Thus the spanning range comes first in a cluster with the
/// same start position.
bool operator<(const Slice &RHS) const {
- if (beginOffset() < RHS.beginOffset()) return true;
- if (beginOffset() > RHS.beginOffset()) return false;
- if (isSplittable() != RHS.isSplittable()) return !isSplittable();
- if (endOffset() > RHS.endOffset()) return true;
+ if (beginOffset() < RHS.beginOffset())
+ return true;
+ if (beginOffset() > RHS.beginOffset())
+ return false;
+ if (isSplittable() != RHS.isSplittable())
+ return !isSplittable();
+ if (endOffset() > RHS.endOffset())
+ return true;
return false;
}
namespace llvm {
template <typename T> struct isPodLike;
-template <> struct isPodLike<Slice> {
- static const bool value = true;
-};
+template <> struct isPodLike<Slice> { static const bool value = true; };
}
namespace {
/// \brief Support for iterating over the slices.
/// @{
typedef SmallVectorImpl<Slice>::iterator iterator;
+ typedef iterator_range<iterator> range;
iterator begin() { return Slices.begin(); }
iterator end() { return Slices.end(); }
typedef SmallVectorImpl<Slice>::const_iterator const_iterator;
+ typedef iterator_range<const_iterator> const_range;
const_iterator begin() const { return Slices.begin(); }
const_iterator end() const { return Slices.end(); }
/// @}
- /// \brief Allow iterating the dead users for this alloca.
+ /// \brief Erase a range of slices.
+ void erase(iterator Start, iterator Stop) { Slices.erase(Start, Stop); }
+
+ /// \brief Insert new slices 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(); }
- /// @}
+ /// This moves the slices into the alloca's slices collection, and re-sorts
+ /// everything so that the usual ordering properties of the alloca's slices
+ /// hold.
+ void insert(ArrayRef<Slice> NewSlices) {
+ int OldSize = Slices.size();
+ std::move(NewSlices.begin(), NewSlices.end(), std::back_inserter(Slices));
+ auto SliceI = Slices.begin() + OldSize;
+ std::sort(SliceI, Slices.end());
+ std::inplace_merge(Slices.begin(), SliceI, Slices.end());
+ }
+
+ // Forward declare an iterator to befriend it.
+ class partition_iterator;
+
+ /// \brief A partition of the slices.
+ ///
+ /// An ephemeral representation for a range of slices which can be viewed as
+ /// a partition of the alloca. This range represents a span of the alloca's
+ /// memory which cannot be split, and provides access to all of the slices
+ /// overlapping some part of the partition.
+ ///
+ /// Objects of this type are produced by traversing the alloca's slices, but
+ /// are only ephemeral and not persistent.
+ class Partition {
+ private:
+ friend class AllocaSlices;
+ friend class AllocaSlices::partition_iterator;
+
+ /// \brief The begining and ending offsets of the alloca for this partition.
+ uint64_t BeginOffset, EndOffset;
+
+ /// \brief The start end end iterators of this partition.
+ iterator SI, SJ;
+
+ /// \brief A collection of split slice tails overlapping the partition.
+ SmallVector<Slice *, 4> SplitTails;
+
+ /// \brief Raw constructor builds an empty partition starting and ending at
+ /// the given iterator.
+ Partition(iterator SI) : SI(SI), SJ(SI) {}
+
+ public:
+ /// \brief The start offset of this partition.
+ ///
+ /// All of the contained slices start at or after this offset.
+ uint64_t beginOffset() const { return BeginOffset; }
- /// \brief Allow iterating the dead expressions referring to this alloca.
+ /// \brief The end offset of this partition.
+ ///
+ /// All of the contained slices end at or before this offset.
+ uint64_t endOffset() const { return EndOffset; }
+
+ /// \brief The size of the partition.
+ ///
+ /// Note that this can never be zero.
+ uint64_t size() const {
+ assert(BeginOffset < EndOffset && "Partitions must span some bytes!");
+ return EndOffset - BeginOffset;
+ }
+
+ /// \brief Test whether this partition contains no slices, and merely spans
+ /// a region occupied by split slices.
+ bool empty() const { return SI == SJ; }
+
+ /// \name Iterate slices that start within the partition.
+ /// These may be splittable or unsplittable. They have a begin offset >= the
+ /// partition begin offset.
+ /// @{
+ // FIXME: We should probably define a "concat_iterator" helper and use that
+ // to stitch together pointee_iterators over the split tails and the
+ // contiguous iterators of the partition. That would give a much nicer
+ // interface here. We could then additionally expose filtered iterators for
+ // split, unsplit, and unsplittable splices based on the usage patterns.
+ iterator begin() const { return SI; }
+ iterator end() const { return SJ; }
+ /// @}
+
+ /// \brief Get the sequence of split slice tails.
+ ///
+ /// These tails are of slices which start before this partition but are
+ /// split and overlap into the partition. We accumulate these while forming
+ /// partitions.
+ ArrayRef<Slice *> splitSliceTails() const { return SplitTails; }
+ };
+
+ /// \brief An iterator over partitions of the alloca's slices.
+ ///
+ /// This iterator implements the core algorithm for partitioning the alloca's
+ /// slices. It is a forward iterator as we don't support backtracking for
+ /// efficiency reasons, and re-use a single storage area to maintain the
+ /// current set of split slices.
+ ///
+ /// It is templated on the slice iterator type to use so that it can operate
+ /// with either const or non-const slice iterators.
+ class partition_iterator
+ : public iterator_facade_base<partition_iterator,
+ std::forward_iterator_tag, Partition> {
+ friend class AllocaSlices;
+
+ /// \brief Most of the state for walking the partitions is held in a class
+ /// with a nice interface for examining them.
+ Partition P;
+
+ /// \brief We need to keep the end of the slices to know when to stop.
+ AllocaSlices::iterator SE;
+
+ /// \brief We also need to keep track of the maximum split end offset seen.
+ /// FIXME: Do we really?
+ uint64_t MaxSplitSliceEndOffset;
+
+ /// \brief Sets the partition to be empty at given iterator, and sets the
+ /// end iterator.
+ partition_iterator(AllocaSlices::iterator SI, AllocaSlices::iterator SE)
+ : P(SI), SE(SE), MaxSplitSliceEndOffset(0) {
+ // If not already at the end, advance our state to form the initial
+ // partition.
+ if (SI != SE)
+ advance();
+ }
+
+ /// \brief Advance the iterator to the next partition.
+ ///
+ /// Requires that the iterator not be at the end of the slices.
+ void advance() {
+ assert((P.SI != SE || !P.SplitTails.empty()) &&
+ "Cannot advance past the end of the slices!");
+
+ // Clear out any split uses which have ended.
+ if (!P.SplitTails.empty()) {
+ if (P.EndOffset >= MaxSplitSliceEndOffset) {
+ // If we've finished all splits, this is easy.
+ P.SplitTails.clear();
+ MaxSplitSliceEndOffset = 0;
+ } else {
+ // Remove the uses which have ended in the prior partition. This
+ // cannot change the max split slice end because we just checked that
+ // the prior partition ended prior to that max.
+ P.SplitTails.erase(
+ std::remove_if(
+ P.SplitTails.begin(), P.SplitTails.end(),
+ [&](Slice *S) { return S->endOffset() <= P.EndOffset; }),
+ P.SplitTails.end());
+ assert(std::any_of(P.SplitTails.begin(), P.SplitTails.end(),
+ [&](Slice *S) {
+ return S->endOffset() == MaxSplitSliceEndOffset;
+ }) &&
+ "Could not find the current max split slice offset!");
+ assert(std::all_of(P.SplitTails.begin(), P.SplitTails.end(),
+ [&](Slice *S) {
+ return S->endOffset() <= MaxSplitSliceEndOffset;
+ }) &&
+ "Max split slice end offset is not actually the max!");
+ }
+ }
+
+ // If P.SI is already at the end, then we've cleared the split tail and
+ // now have an end iterator.
+ if (P.SI == SE) {
+ assert(P.SplitTails.empty() && "Failed to clear the split slices!");
+ return;
+ }
+
+ // If we had a non-empty partition previously, set up the state for
+ // subsequent partitions.
+ if (P.SI != P.SJ) {
+ // Accumulate all the splittable slices which started in the old
+ // partition into the split list.
+ for (Slice &S : P)
+ if (S.isSplittable() && S.endOffset() > P.EndOffset) {
+ P.SplitTails.push_back(&S);
+ MaxSplitSliceEndOffset =
+ std::max(S.endOffset(), MaxSplitSliceEndOffset);
+ }
+
+ // Start from the end of the previous partition.
+ P.SI = P.SJ;
+
+ // If P.SI is now at the end, we at most have a tail of split slices.
+ if (P.SI == SE) {
+ P.BeginOffset = P.EndOffset;
+ P.EndOffset = MaxSplitSliceEndOffset;
+ return;
+ }
+
+ // If the we have split slices and the next slice is after a gap and is
+ // not splittable immediately form an empty partition for the split
+ // slices up until the next slice begins.
+ if (!P.SplitTails.empty() && P.SI->beginOffset() != P.EndOffset &&
+ !P.SI->isSplittable()) {
+ P.BeginOffset = P.EndOffset;
+ P.EndOffset = P.SI->beginOffset();
+ return;
+ }
+ }
+
+ // OK, we need to consume new slices. Set the end offset based on the
+ // current slice, and step SJ past it. The beginning offset of the
+ // parttion is the beginning offset of the next slice unless we have
+ // pre-existing split slices that are continuing, in which case we begin
+ // at the prior end offset.
+ P.BeginOffset = P.SplitTails.empty() ? P.SI->beginOffset() : P.EndOffset;
+ P.EndOffset = P.SI->endOffset();
+ ++P.SJ;
+
+ // There are two strategies to form a partition based on whether the
+ // partition starts with an unsplittable slice or a splittable slice.
+ if (!P.SI->isSplittable()) {
+ // When we're forming an unsplittable region, it must always start at
+ // the first slice and will extend through its end.
+ assert(P.BeginOffset == P.SI->beginOffset());
+
+ // Form a partition including all of the overlapping slices with this
+ // unsplittable slice.
+ while (P.SJ != SE && P.SJ->beginOffset() < P.EndOffset) {
+ if (!P.SJ->isSplittable())
+ P.EndOffset = std::max(P.EndOffset, P.SJ->endOffset());
+ ++P.SJ;
+ }
+
+ // We have a partition across a set of overlapping unsplittable
+ // partitions.
+ return;
+ }
+
+ // If we're starting with a splittable slice, then we need to form
+ // a synthetic partition spanning it and any other overlapping splittable
+ // splices.
+ assert(P.SI->isSplittable() && "Forming a splittable partition!");
+
+ // Collect all of the overlapping splittable slices.
+ while (P.SJ != SE && P.SJ->beginOffset() < P.EndOffset &&
+ P.SJ->isSplittable()) {
+ P.EndOffset = std::max(P.EndOffset, P.SJ->endOffset());
+ ++P.SJ;
+ }
+
+ // Back upiP.EndOffset if we ended the span early when encountering an
+ // unsplittable slice. This synthesizes the early end offset of
+ // a partition spanning only splittable slices.
+ if (P.SJ != SE && P.SJ->beginOffset() < P.EndOffset) {
+ assert(!P.SJ->isSplittable());
+ P.EndOffset = P.SJ->beginOffset();
+ }
+ }
+
+ public:
+ bool operator==(const partition_iterator &RHS) const {
+ assert(SE == RHS.SE &&
+ "End iterators don't match between compared partition iterators!");
+
+ // The observed positions of partitions is marked by the P.SI iterator and
+ // the emptyness of the split slices. The latter is only relevant when
+ // P.SI == SE, as the end iterator will additionally have an empty split
+ // slices list, but the prior may have the same P.SI and a tail of split
+ // slices.
+ if (P.SI == RHS.P.SI &&
+ P.SplitTails.empty() == RHS.P.SplitTails.empty()) {
+ assert(P.SJ == RHS.P.SJ &&
+ "Same set of slices formed two different sized partitions!");
+ assert(P.SplitTails.size() == RHS.P.SplitTails.size() &&
+ "Same slice position with differently sized non-empty split "
+ "slice tails!");
+ return true;
+ }
+ return false;
+ }
+
+ partition_iterator &operator++() {
+ advance();
+ return *this;
+ }
+
+ Partition &operator*() { return P; }
+ };
+
+ /// \brief A forward range over the partitions of the alloca's slices.
+ ///
+ /// This accesses an iterator range over the partitions of the alloca's
+ /// slices. It computes these partitions on the fly based on the overlapping
+ /// offsets of the slices and the ability to split them. It will visit "empty"
+ /// partitions to cover regions of the alloca only accessed via split
+ /// slices.
+ iterator_range<partition_iterator> partitions() {
+ return make_range(partition_iterator(begin(), end()),
+ partition_iterator(end(), end()));
+ }
+
+ /// \brief Access the dead users for this alloca.
+ ArrayRef<Instruction *> getDeadUsers() const { return DeadUsers; }
+
+ /// \brief Access 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(); }
- /// @}
+ ArrayRef<Use *> getDeadOperands() const { return DeadOperands; }
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void print(raw_ostream &OS, const_iterator I, StringRef Indent = " ") const;
// 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());
+ return SI.getOperand(1 + CI->isZero());
if (SI.getOperand(1) == SI.getOperand(2))
return SI.getOperand(1);
- return 0;
+ return nullptr;
+}
+
+/// \brief A helper that folds a PHI node or a select.
+static Value *foldPHINodeOrSelectInst(Instruction &I) {
+ if (PHINode *PN = dyn_cast<PHINode>(&I)) {
+ // If PN merges together the same value, return that value.
+ return PN->hasConstantValue();
+ }
+ return foldSelectInst(cast<SelectInst>(I));
}
/// \brief Builder for the alloca slices.
typedef PtrUseVisitor<SliceBuilder> Base;
const uint64_t AllocSize;
- AllocaSlices &S;
+ AllocaSlices &AS;
SmallDenseMap<Instruction *, unsigned> MemTransferSliceMap;
SmallDenseMap<Instruction *, uint64_t> PHIOrSelectSizes;
SmallPtrSet<Instruction *, 4> VisitedDeadInsts;
public:
- SliceBuilder(const DataLayout &DL, AllocaInst &AI, AllocaSlices &S)
+ SliceBuilder(const DataLayout &DL, AllocaInst &AI, AllocaSlices &AS)
: PtrUseVisitor<SliceBuilder>(DL),
- AllocSize(DL.getTypeAllocSize(AI.getAllocatedType())), S(S) {}
+ AllocSize(DL.getTypeAllocSize(AI.getAllocatedType())), AS(AS) {}
private:
void markAsDead(Instruction &I) {
- if (VisitedDeadInsts.insert(&I))
- S.DeadUsers.push_back(&I);
+ if (VisitedDeadInsts.insert(&I).second)
+ AS.DeadUsers.push_back(&I);
}
void insertUse(Instruction &I, const APInt &Offset, uint64_t Size,
bool IsSplittable = false) {
// Completely skip uses which have a zero size or start either before or
// past the end of the allocation.
- if (Size == 0 || Offset.isNegative() || Offset.uge(AllocSize)) {
+ if (Size == 0 || Offset.uge(AllocSize)) {
DEBUG(dbgs() << "WARNING: Ignoring " << Size << " byte use @" << Offset
<< " which has zero size or starts outside of the "
<< AllocSize << " byte alloca:\n"
- << " alloca: " << S.AI << "\n"
+ << " alloca: " << AS.AI << "\n"
<< " use: " << I << "\n");
return markAsDead(I);
}
if (Size > AllocSize - BeginOffset) {
DEBUG(dbgs() << "WARNING: Clamping a " << Size << " byte use @" << Offset
<< " to remain within the " << AllocSize << " byte alloca:\n"
- << " alloca: " << S.AI << "\n"
+ << " alloca: " << AS.AI << "\n"
<< " use: " << I << "\n");
EndOffset = AllocSize;
}
- S.Slices.push_back(Slice(BeginOffset, EndOffset, U, IsSplittable));
+ AS.Slices.push_back(Slice(BeginOffset, EndOffset, U, IsSplittable));
}
void visitBitCastInst(BitCastInst &BC) {
GEPOffset +=
APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx));
} else {
- // For array or vector indices, scale the index by the size of the type.
+ // For array or vector indices, scale the index by the size of the
+ // type.
APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth());
GEPOffset += Index * APInt(Offset.getBitWidth(),
DL.getTypeAllocSize(GTI.getIndexedType()));
void handleLoadOrStore(Type *Ty, Instruction &I, const APInt &Offset,
uint64_t Size, bool IsVolatile) {
- // We allow splitting of loads and stores where the type is an integer type
- // and cover the entire alloca. This prevents us from splitting over
- // eagerly.
- // FIXME: In the great blue eventually, we should eagerly split all integer
- // loads and stores, and then have a separate step that merges adjacent
- // alloca partitions into a single partition suitable for integer widening.
- // Or we should skip the merge step and rely on GVN and other passes to
- // merge adjacent loads and stores that survive mem2reg.
- bool IsSplittable =
- Ty->isIntegerTy() && !IsVolatile && Offset == 0 && Size >= AllocSize;
+ // We allow splitting of non-volatile loads and stores where the type is an
+ // integer type. These may be used to implement 'memcpy' or other "transfer
+ // of bits" patterns.
+ bool IsSplittable = Ty->isIntegerTy() && !IsVolatile;
insertUse(I, Offset, Size, IsSplittable);
}
// 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.isNegative() || Size > AllocSize ||
- Offset.ugt(AllocSize - Size)) {
+ if (Size > AllocSize || Offset.ugt(AllocSize - Size)) {
DEBUG(dbgs() << "WARNING: Ignoring " << Size << " byte store @" << Offset
<< " which extends past the end of the " << AllocSize
<< " byte alloca:\n"
- << " alloca: " << S.AI << "\n"
+ << " alloca: " << AS.AI << "\n"
<< " use: " << SI << "\n");
return markAsDead(SI);
}
handleLoadOrStore(ValOp->getType(), SI, Offset, Size, SI.isVolatile());
}
-
void visitMemSetInst(MemSetInst &II) {
assert(II.getRawDest() == *U && "Pointer use is not the destination?");
ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
if ((Length && Length->getValue() == 0) ||
- (IsOffsetKnown && !Offset.isNegative() && Offset.uge(AllocSize)))
+ (IsOffsetKnown && Offset.uge(AllocSize)))
// Zero-length mem transfer intrinsics can be ignored entirely.
return markAsDead(II);
if (!IsOffsetKnown)
return PI.setAborted(&II);
- insertUse(II, Offset,
- Length ? Length->getLimitedValue()
- : AllocSize - Offset.getLimitedValue(),
+ insertUse(II, Offset, Length ? Length->getLimitedValue()
+ : AllocSize - Offset.getLimitedValue(),
(bool)Length);
}
// if already added to our partitions.
// FIXME: Yet another place we really should bypass this when
// instrumenting for ASan.
- if (!Offset.isNegative() && Offset.uge(AllocSize)) {
- SmallDenseMap<Instruction *, unsigned>::iterator MTPI = MemTransferSliceMap.find(&II);
+ if (Offset.uge(AllocSize)) {
+ SmallDenseMap<Instruction *, unsigned>::iterator MTPI =
+ MemTransferSliceMap.find(&II);
if (MTPI != MemTransferSliceMap.end())
- S.Slices[MTPI->second].kill();
+ AS.Slices[MTPI->second].kill();
return markAsDead(II);
}
uint64_t RawOffset = Offset.getLimitedValue();
- uint64_t Size = Length ? Length->getLimitedValue()
- : AllocSize - RawOffset;
+ uint64_t Size = Length ? Length->getLimitedValue() : AllocSize - RawOffset;
// Check for the special case where the same exact value is used for both
// source and dest.
// they both point to the same alloca.
bool Inserted;
SmallDenseMap<Instruction *, unsigned>::iterator MTPI;
- llvm::tie(MTPI, Inserted) =
- MemTransferSliceMap.insert(std::make_pair(&II, S.Slices.size()));
+ std::tie(MTPI, Inserted) =
+ MemTransferSliceMap.insert(std::make_pair(&II, AS.Slices.size()));
unsigned PrevIdx = MTPI->second;
if (!Inserted) {
- Slice &PrevP = S.Slices[PrevIdx];
+ Slice &PrevP = AS.Slices[PrevIdx];
// Check if the begin offsets match and this is a non-volatile transfer.
// In that case, we can completely elide the transfer.
insertUse(II, Offset, Size, /*IsSplittable=*/Inserted && Length);
// Check that we ended up with a valid index in the map.
- assert(S.Slices[PrevIdx].getUse()->getUser() == &II &&
+ assert(AS.Slices[PrevIdx].getUse()->getUser() == &II &&
"Map index doesn't point back to a slice with this user.");
}
Size = 0;
do {
Instruction *I, *UsedI;
- llvm::tie(UsedI, I) = Uses.pop_back_val();
+ std::tie(UsedI, I) = Uses.pop_back_val();
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
Size = std::max(Size, DL.getTypeStoreSize(LI->getType()));
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)));
+ for (User *U : I->users())
+ if (Visited.insert(cast<Instruction>(U)).second)
+ Uses.push_back(std::make_pair(I, cast<Instruction>(U)));
} while (!Uses.empty());
- return 0;
+ return nullptr;
}
- void visitPHINode(PHINode &PN) {
- if (PN.use_empty())
- return markAsDead(PN);
- if (!IsOffsetKnown)
- return PI.setAborted(&PN);
-
- // See if we already have computed info on this node.
- uint64_t &PHISize = PHIOrSelectSizes[&PN];
- if (!PHISize) {
- // This is a new PHI node, check for an unsafe use of the PHI node.
- if (Instruction *UnsafeI = hasUnsafePHIOrSelectUse(&PN, PHISize))
- return PI.setAborted(UnsafeI);
- }
-
- // 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.
- // FIXME: This should instead be escaped in the event we're instrumenting
- // for address sanitization.
- if ((Offset.isNegative() && (-Offset).uge(PHISize)) ||
- (!Offset.isNegative() && Offset.uge(AllocSize))) {
- S.DeadOperands.push_back(U);
- return;
- }
-
- insertUse(PN, Offset, PHISize);
- }
+ void visitPHINodeOrSelectInst(Instruction &I) {
+ assert(isa<PHINode>(I) || isa<SelectInst>(I));
+ if (I.use_empty())
+ return markAsDead(I);
- void visitSelectInst(SelectInst &SI) {
- if (SI.use_empty())
- return markAsDead(SI);
- if (Value *Result = foldSelectInst(SI)) {
+ // TODO: We could use SimplifyInstruction here to fold PHINodes and
+ // SelectInsts. However, doing so requires to change the current
+ // dead-operand-tracking mechanism. For instance, suppose neither loading
+ // from %U nor %other traps. Then "load (select undef, %U, %other)" does not
+ // trap either. However, if we simply replace %U with undef using the
+ // current dead-operand-tracking mechanism, "load (select undef, undef,
+ // %other)" may trap because the select may return the first operand
+ // "undef".
+ if (Value *Result = foldPHINodeOrSelectInst(I)) {
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);
+ // through the PHI/select as if we had RAUW'ed it.
+ enqueueUsers(I);
else
- // Otherwise the operand to the select is dead, and we can replace it
- // with undef.
- S.DeadOperands.push_back(U);
+ // Otherwise the operand to the PHI/select is dead, and we can replace
+ // it with undef.
+ AS.DeadOperands.push_back(U);
return;
}
+
if (!IsOffsetKnown)
- return PI.setAborted(&SI);
+ return PI.setAborted(&I);
// See if we already have computed info on this node.
- uint64_t &SelectSize = PHIOrSelectSizes[&SI];
- if (!SelectSize) {
- // This is a new Select, check for an unsafe use of it.
- if (Instruction *UnsafeI = hasUnsafePHIOrSelectUse(&SI, SelectSize))
+ uint64_t &Size = PHIOrSelectSizes[&I];
+ if (!Size) {
+ // This is a new PHI/Select, check for an unsafe use of it.
+ if (Instruction *UnsafeI = hasUnsafePHIOrSelectUse(&I, Size))
return PI.setAborted(UnsafeI);
}
// themselves which should be replaced with undef.
// FIXME: This should instead be escaped in the event we're instrumenting
// for address sanitization.
- if ((Offset.isNegative() && Offset.uge(SelectSize)) ||
- (!Offset.isNegative() && Offset.uge(AllocSize))) {
- S.DeadOperands.push_back(U);
+ if (Offset.uge(AllocSize)) {
+ AS.DeadOperands.push_back(U);
return;
}
- insertUse(SI, Offset, SelectSize);
+ insertUse(I, Offset, Size);
}
+ void visitPHINode(PHINode &PN) { visitPHINodeOrSelectInst(PN); }
+
+ void visitSelectInst(SelectInst &SI) { visitPHINodeOrSelectInst(SI); }
+
/// \brief Disable SROA entirely if there are unhandled users of the alloca.
- void visitInstruction(Instruction &I) {
- PI.setAborted(&I);
- }
+ void visitInstruction(Instruction &I) { PI.setAborted(&I); }
};
AllocaSlices::AllocaSlices(const DataLayout &DL, AllocaInst &AI)
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
AI(AI),
#endif
- PointerEscapingInstr(0) {
+ PointerEscapingInstr(nullptr) {
SliceBuilder PB(DL, AI, *this);
SliceBuilder::PtrInfo PtrI = PB.visitPtr(AI);
if (PtrI.isEscaped() || PtrI.isAborted()) {
}
Slices.erase(std::remove_if(Slices.begin(), Slices.end(),
- std::mem_fun_ref(&Slice::isDead)),
+ [](const Slice &S) {
+ return S.isDead();
+ }),
Slices.end());
#if __cplusplus >= 201103L && !defined(NDEBUG)
void AllocaSlices::print(raw_ostream &OS, const_iterator I,
StringRef Indent) const {
printSlice(OS, I, Indent);
+ OS << "\n";
printUse(OS, I, Indent);
}
StringRef Indent) const {
OS << Indent << "[" << I->beginOffset() << "," << I->endOffset() << ")"
<< " slice #" << (I - begin())
- << (I->isSplittable() ? " (splittable)" : "") << "\n";
+ << (I->isSplittable() ? " (splittable)" : "");
}
void AllocaSlices::printUse(raw_ostream &OS, const_iterator I,
AllocaInst &AI, DIBuilder &DIB)
: LoadAndStorePromoter(Insts, S), AI(AI), DIB(DIB) {}
- void run(const SmallVectorImpl<Instruction*> &Insts) {
+ void run(const SmallVectorImpl<Instruction *> &Insts) {
// Retain the debug information attached to the alloca for use when
// rewriting loads and stores.
- if (MDNode *DebugNode = MDNode::getIfExists(AI.getContext(), &AI)) {
- for (Value::use_iterator UI = DebugNode->use_begin(),
- UE = DebugNode->use_end();
- UI != UE; ++UI)
- if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(*UI))
- DDIs.push_back(DDI);
- else if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(*UI))
- DVIs.push_back(DVI);
+ if (auto *L = LocalAsMetadata::getIfExists(&AI)) {
+ if (auto *DebugNode = MetadataAsValue::getIfExists(AI.getContext(), L)) {
+ for (User *U : DebugNode->users())
+ if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(U))
+ DDIs.push_back(DDI);
+ else if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(U))
+ DVIs.push_back(DVI);
+ }
}
LoadAndStorePromoter::run(Insts);
DVIs.pop_back_val()->eraseFromParent();
}
- virtual bool isInstInList(Instruction *I,
- const SmallVectorImpl<Instruction*> &Insts) const {
+ bool
+ isInstInList(Instruction *I,
+ const SmallVectorImpl<Instruction *> &Insts) const override {
Value *Ptr;
if (LoadInst *LI = dyn_cast<LoadInst>(I))
Ptr = LI->getOperand(0);
else
return false;
- } while (Visited.insert(Ptr));
+ } while (Visited.insert(Ptr).second);
return false;
}
- virtual void updateDebugInfo(Instruction *Inst) const {
- for (SmallVectorImpl<DbgDeclareInst *>::const_iterator I = DDIs.begin(),
- E = DDIs.end(); I != E; ++I) {
- DbgDeclareInst *DDI = *I;
+ void updateDebugInfo(Instruction *Inst) const override {
+ for (DbgDeclareInst *DDI : DDIs)
if (StoreInst *SI = dyn_cast<StoreInst>(Inst))
ConvertDebugDeclareToDebugValue(DDI, SI, DIB);
else if (LoadInst *LI = dyn_cast<LoadInst>(Inst))
ConvertDebugDeclareToDebugValue(DDI, LI, DIB);
- }
- for (SmallVectorImpl<DbgValueInst *>::const_iterator I = DVIs.begin(),
- E = DVIs.end(); I != E; ++I) {
- DbgValueInst *DVI = *I;
- Value *Arg = 0;
+ for (DbgValueInst *DVI : DVIs) {
+ Value *Arg = nullptr;
if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
// If an argument is zero extended then use argument directly. The ZExt
// may be zapped by an optimization pass in future.
continue;
}
Instruction *DbgVal =
- DIB.insertDbgValueIntrinsic(Arg, 0, DIVariable(DVI->getVariable()),
- Inst);
+ DIB.insertDbgValueIntrinsic(Arg, 0, DIVariable(DVI->getVariable()),
+ DIExpression(DVI->getExpression()), Inst);
DbgVal->setDebugLoc(DVI->getDebugLoc());
}
}
};
} // end anon namespace
-
namespace {
/// \brief An optimization pass providing Scalar Replacement of Aggregates.
///
LLVMContext *C;
const DataLayout *DL;
DominatorTree *DT;
+ AssumptionCache *AC;
/// \brief Worklist of alloca instructions to simplify.
///
/// 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;
+ 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.
- SetVector<Instruction *, SmallVector<Instruction *, 8> > DeadInsts;
+ SetVector<Instruction *, SmallVector<Instruction *, 8>> DeadInsts;
/// \brief Post-promotion worklist.
///
///
/// Note that we have to be very careful to clear allocas out of this list in
/// the event they are deleted.
- SetVector<AllocaInst *, SmallVector<AllocaInst *, 16> > PostPromotionWorklist;
+ SetVector<AllocaInst *, SmallVector<AllocaInst *, 16>> PostPromotionWorklist;
/// \brief A collection of alloca instructions we can directly promote.
std::vector<AllocaInst *> PromotableAllocas;
/// All of these PHIs have been checked for the safety of speculation and by
/// being speculated will allow promoting allocas currently in the promotable
/// queue.
- SetVector<PHINode *, SmallVector<PHINode *, 2> > SpeculatablePHIs;
+ SetVector<PHINode *, SmallVector<PHINode *, 2>> SpeculatablePHIs;
/// \brief A worklist of select instructions to speculate prior to promoting
/// allocas.
/// All of these select instructions have been checked for the safety of
/// speculation and by being speculated will allow promoting allocas
/// currently in the promotable queue.
- SetVector<SelectInst *, SmallVector<SelectInst *, 2> > SpeculatableSelects;
+ SetVector<SelectInst *, SmallVector<SelectInst *, 2>> SpeculatableSelects;
+
+ /// Debug intrinsics do not show up as regular uses in the
+ /// IR. This side-table holds the missing use edges.
+ DenseMap<AllocaInst *, DbgDeclareInst *> DbgDeclares;
public:
SROA(bool RequiresDomTree = true)
- : FunctionPass(ID), RequiresDomTree(RequiresDomTree),
- C(0), DL(0), DT(0) {
+ : FunctionPass(ID), RequiresDomTree(RequiresDomTree), C(nullptr),
+ DL(nullptr), DT(nullptr) {
initializeSROAPass(*PassRegistry::getPassRegistry());
}
- bool runOnFunction(Function &F);
- void getAnalysisUsage(AnalysisUsage &AU) const;
+ bool runOnFunction(Function &F) override;
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
- const char *getPassName() const { return "SROA"; }
+ const char *getPassName() const override { return "SROA"; }
static char ID;
private:
friend class PHIOrSelectSpeculator;
friend class AllocaSliceRewriter;
- bool rewritePartition(AllocaInst &AI, AllocaSlices &S,
- AllocaSlices::iterator B, AllocaSlices::iterator E,
- int64_t BeginOffset, int64_t EndOffset,
- ArrayRef<AllocaSlices::iterator> SplitUses);
- bool splitAlloca(AllocaInst &AI, AllocaSlices &S);
+ bool presplitLoadsAndStores(AllocaInst &AI, AllocaSlices &AS);
+ AllocaInst *rewritePartition(AllocaInst &AI, AllocaSlices &AS,
+ AllocaSlices::Partition &P);
+ bool splitAlloca(AllocaInst &AI, AllocaSlices &AS);
bool runOnAlloca(AllocaInst &AI);
void clobberUse(Use &U);
- void deleteDeadInstructions(SmallPtrSet<AllocaInst *, 4> &DeletedAllocas);
+ void deleteDeadInstructions(SmallPtrSetImpl<AllocaInst *> &DeletedAllocas);
bool promoteAllocas(Function &F);
};
}
return new SROA(RequiresDomTree);
}
-INITIALIZE_PASS_BEGIN(SROA, "sroa", "Scalar Replacement Of Aggregates",
- false, false)
+INITIALIZE_PASS_BEGIN(SROA, "sroa", "Scalar Replacement Of Aggregates", false,
+ false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_END(SROA, "sroa", "Scalar Replacement Of Aggregates",
- false, false)
+INITIALIZE_PASS_END(SROA, "sroa", "Scalar Replacement Of Aggregates", false,
+ false)
/// Walk the range of a partitioning looking for a common type to cover this
/// sequence of slices.
static Type *findCommonType(AllocaSlices::const_iterator B,
AllocaSlices::const_iterator E,
uint64_t EndOffset) {
- Type *Ty = 0;
+ Type *Ty = nullptr;
bool TyIsCommon = true;
- IntegerType *ITy = 0;
+ IntegerType *ITy = nullptr;
// Note that we need to look at *every* alloca slice's Use to ensure we
// always get consistent results regardless of the order of slices.
if (I->beginOffset() != B->beginOffset() || I->endOffset() != EndOffset)
continue;
- Type *UserTy = 0;
+ Type *UserTy = nullptr;
if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
UserTy = LI->getType();
} else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
UserTy = SI->getValueOperand()->getType();
}
- if (!UserTy || (Ty && Ty != UserTy))
- TyIsCommon = false; // Give up on anything but an iN type.
- else
- Ty = UserTy;
-
if (IntegerType *UserITy = dyn_cast_or_null<IntegerType>(UserTy)) {
// If the type is larger than the partition, skip it. We only encounter
// this for split integer operations where we want to use the type of the
if (!ITy || ITy->getBitWidth() < UserITy->getBitWidth())
ITy = UserITy;
}
+
+ // To avoid depending on the order of slices, Ty and TyIsCommon must not
+ // depend on types skipped above.
+ if (!UserTy || (Ty && Ty != UserTy))
+ TyIsCommon = false; // Give up on anything but an iN type.
+ else
+ Ty = UserTy;
}
return TyIsCommon ? Ty : ITy;
///
/// FIXME: This should be hoisted into a generic utility, likely in
/// Transforms/Util/Local.h
-static bool isSafePHIToSpeculate(PHINode &PN,
- const DataLayout *DL = 0) {
+static bool isSafePHIToSpeculate(PHINode &PN, const DataLayout *DL = nullptr) {
// 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.
BasicBlock *BB = PN.getParent();
unsigned MaxAlign = 0;
bool HaveLoad = false;
- 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())
+ for (User *U : PN.users()) {
+ LoadInst *LI = dyn_cast<LoadInst>(U);
+ if (!LI || !LI->isSimple())
return false;
// For now we only allow loads in the same block as the PHI. This is
// 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() ||
+ if (InVal->isDereferenceablePointer(DL) ||
isSafeToLoadUnconditionally(InVal, TI, MaxAlign, DL))
continue;
PHINode *NewPN = PHIBuilder.CreatePHI(LoadTy, PN.getNumIncomingValues(),
PN.getName() + ".sroa.speculated");
- // Get the TBAA tag and alignment to use from one of the loads. It doesn't
+ // Get the AA tags and alignment to use from one of the loads. It doesn't
// matter which one we get and if any differ.
- LoadInst *SomeLoad = cast<LoadInst>(*PN.use_begin());
- MDNode *TBAATag = SomeLoad->getMetadata(LLVMContext::MD_tbaa);
+ LoadInst *SomeLoad = cast<LoadInst>(PN.user_back());
+
+ AAMDNodes AATags;
+ SomeLoad->getAAMetadata(AATags);
unsigned Align = SomeLoad->getAlignment();
// Rewrite all loads of the PN to use the new PHI.
while (!PN.use_empty()) {
- LoadInst *LI = cast<LoadInst>(*PN.use_begin());
+ LoadInst *LI = cast<LoadInst>(PN.user_back());
LI->replaceAllUsesWith(NewPN);
LI->eraseFromParent();
}
InVal, (PN.getName() + ".sroa.speculate.load." + Pred->getName()));
++NumLoadsSpeculated;
Load->setAlignment(Align);
- if (TBAATag)
- Load->setMetadata(LLVMContext::MD_tbaa, TBAATag);
+ if (AATags)
+ Load->setAAMetadata(AATags);
NewPN->addIncoming(Load, Pred);
}
///
/// We can do this to a select if its only uses are loads and if the operand
/// to the select can be loaded unconditionally.
-static bool isSafeSelectToSpeculate(SelectInst &SI, const DataLayout *DL = 0) {
+static bool isSafeSelectToSpeculate(SelectInst &SI,
+ const DataLayout *DL = nullptr) {
Value *TValue = SI.getTrueValue();
Value *FValue = SI.getFalseValue();
- bool TDerefable = TValue->isDereferenceablePointer();
- bool FDerefable = FValue->isDereferenceablePointer();
+ bool TDerefable = TValue->isDereferenceablePointer(DL);
+ bool FDerefable = FValue->isDereferenceablePointer(DL);
- 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())
+ for (User *U : SI.users()) {
+ LoadInst *LI = dyn_cast<LoadInst>(U);
+ if (!LI || !LI->isSimple())
return false;
// Both operands to the select need to be dereferencable, either
Value *FV = SI.getFalseValue();
// Replace the loads of the select with a select of two loads.
while (!SI.use_empty()) {
- LoadInst *LI = cast<LoadInst>(*SI.use_begin());
+ LoadInst *LI = cast<LoadInst>(SI.user_back());
assert(LI->isSimple() && "We only speculate simple loads");
IRB.SetInsertPoint(LI);
IRB.CreateLoad(FV, LI->getName() + ".sroa.speculate.load.false");
NumLoadsSpeculated += 2;
- // Transfer alignment and TBAA info if present.
+ // Transfer alignment and AA 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);
+
+ AAMDNodes Tags;
+ LI->getAAMetadata(Tags);
+ if (Tags) {
+ TL->setAAMetadata(Tags);
+ FL->setAAMetadata(Tags);
}
Value *V = IRB.CreateSelect(SI.getCondition(), TL, FL,
if (Ty == TargetTy)
return buildGEP(IRB, BasePtr, Indices, NamePrefix);
+ // Pointer size to use for the indices.
+ unsigned PtrSize = DL.getPointerTypeSizeInBits(BasePtr->getType());
+
// See if we can descend into a struct and locate a field with the correct
// type.
unsigned NumLayers = 0;
do {
if (ElementTy->isPointerTy())
break;
- if (SequentialType *SeqTy = dyn_cast<SequentialType>(ElementTy)) {
- ElementTy = SeqTy->getElementType();
- // Note that we use the default address space as this index is over an
- // array or a vector, not a pointer.
- Indices.push_back(IRB.getInt(APInt(DL.getPointerSizeInBits(0), 0)));
+
+ if (ArrayType *ArrayTy = dyn_cast<ArrayType>(ElementTy)) {
+ ElementTy = ArrayTy->getElementType();
+ Indices.push_back(IRB.getIntN(PtrSize, 0));
+ } else if (VectorType *VectorTy = dyn_cast<VectorType>(ElementTy)) {
+ ElementTy = VectorTy->getElementType();
+ Indices.push_back(IRB.getInt32(0));
} else if (StructType *STy = dyn_cast<StructType>(ElementTy)) {
if (STy->element_begin() == STy->element_end())
break; // Nothing left to descend into.
@@ -1331,23 +1613,26 @@ static Value *getNaturalGEPRecursively(IRBuilderTy &IRB, const DataLayout &DL,
SmallVectorImpl<Value *> &Indices,
Twine NamePrefix) {
if (Offset == 0)
- return getNaturalGEPWithType(IRB, DL, Ptr, Ty, TargetTy, Indices, NamePrefix);
+ return getNaturalGEPWithType(IRB, DL, Ptr, Ty, TargetTy, Indices,
+ NamePrefix);
// We can't recurse through pointer types.
if (Ty->isPointerTy())
- return 0;
+ return nullptr;
// We try to analyze GEPs over vectors here, but note that these GEPs are
// extremely poorly defined currently. The long-term goal is to remove GEPing
// over a vector from the IR completely.
if (VectorType *VecTy = dyn_cast<VectorType>(Ty)) {
unsigned ElementSizeInBits = DL.getTypeSizeInBits(VecTy->getScalarType());
- if (ElementSizeInBits % 8)
- return 0; // GEPs over non-multiple of 8 size vector elements are invalid.
+ if (ElementSizeInBits % 8 != 0) {
+ // GEPs over non-multiple of 8 size vector elements are invalid.
+ return nullptr;
+ }
APInt ElementSize(Offset.getBitWidth(), ElementSizeInBits / 8);
APInt NumSkippedElements = Offset.sdiv(ElementSize);
if (NumSkippedElements.ugt(VecTy->getNumElements()))
- return 0;
+ return nullptr;
Offset -= NumSkippedElements * ElementSize;
Indices.push_back(IRB.getInt(NumSkippedElements));
return getNaturalGEPRecursively(IRB, DL, Ptr, VecTy->getElementType(),
@@ -1359,7 +1644,7 @@ static Value *getNaturalGEPRecursively(IRBuilderTy &IRB, const DataLayout &DL,
APInt ElementSize(Offset.getBitWidth(), DL.getTypeAllocSize(ElementTy));
APInt NumSkippedElements = Offset.sdiv(ElementSize);
if (NumSkippedElements.ugt(ArrTy->getNumElements()))
- return 0;
+ return nullptr;
Offset -= NumSkippedElements * ElementSize;
Indices.push_back(IRB.getInt(NumSkippedElements));
@@ -1369,17 +1654,17 @@ static Value *getNaturalGEPRecursively(IRBuilderTy &IRB, const DataLayout &DL,
StructType *STy = dyn_cast<StructType>(Ty);
if (!STy)
- return 0;
+ return nullptr;
const StructLayout *SL = DL.getStructLayout(STy);
uint64_t StructOffset = Offset.getZExtValue();
if (StructOffset >= SL->getSizeInBytes())
- return 0;
+ return nullptr;
unsigned Index = SL->getElementContainingOffset(StructOffset);
Offset -= APInt(Offset.getBitWidth(), SL->getElementOffset(Index));
Type *ElementTy = STy->getElementType(Index);
if (Offset.uge(DL.getTypeAllocSize(ElementTy)))
- return 0; // The offset points into alignment padding.
+ return nullptr; // The offset points into alignment padding.
Indices.push_back(IRB.getInt32(Index));
return getNaturalGEPRecursively(IRB, DL, Ptr, ElementTy, Offset, TargetTy,
@@ -1404,15 +1689,15 @@ static Value *getNaturalGEPWithOffset(IRBuilderTy &IRB, const DataLayout &DL,
// 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;
+ if (Ty == IRB.getInt8PtrTy(Ty->getAddressSpace()) && TargetTy->isIntegerTy(8))
+ return nullptr;
Type *ElementTy = Ty->getElementType();
if (!ElementTy->isSized())
- return 0; // We can't GEP through an unsized element.
+ return nullptr; // We can't GEP through an unsized element.
APInt ElementSize(Offset.getBitWidth(), DL.getTypeAllocSize(ElementTy));
if (ElementSize == 0)
- return 0; // Zero-length arrays can't help us build a natural GEP.
+ return nullptr; // Zero-length arrays can't help us build a natural GEP.
APInt NumSkippedElements = Offset.sdiv(ElementSize);
Offset -= NumSkippedElements * ElementSize;
/// a single GEP as possible, thus making each GEP more independent of the
/// surrounding code.
static Value *getAdjustedPtr(IRBuilderTy &IRB, const DataLayout &DL, Value *Ptr,
- APInt Offset, Type *PointerTy,
- Twine NamePrefix) {
+ APInt Offset, Type *PointerTy, Twine NamePrefix) {
// 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;
@@ -1447,12 +1731,13 @@ static Value *getAdjustedPtr(IRBuilderTy &IRB, const DataLayout &DL, Value *Ptr,
// 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;
+ // fall back to it, so keep it and the base it was computed from around here.
+ Value *OffsetPtr = nullptr;
+ Value *OffsetBasePtr;
// Remember any i8 pointer we come across to re-use if we need to do a raw
// byte offset.
- Value *Int8Ptr = 0;
+ Value *Int8Ptr = nullptr;
APInt Int8PtrOffset(Offset.getBitWidth(), 0);
Type *TargetTy = PointerTy->getPointerElementType();
@@ -1465,7 +1750,7 @@ static Value *getAdjustedPtr(IRBuilderTy &IRB, const DataLayout &DL, Value *Ptr,
break;
Offset += GEPOffset;
Ptr = GEP->getPointerOperand();
- if (!Visited.insert(Ptr))
+ if (!Visited.insert(Ptr).second)
break;
}
@@ -1473,16 +1758,19 @@ static Value *getAdjustedPtr(IRBuilderTy &IRB, const DataLayout &DL, Value *Ptr,
Indices.clear();
if (Value *P = getNaturalGEPWithOffset(IRB, DL, Ptr, Offset, TargetTy,
Indices, NamePrefix)) {
- 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();
+ // If we have a new natural pointer at the offset, clear out any old
+ // offset pointer we computed. Unless it is the base pointer or
+ // a non-instruction, we built a GEP we don't need. Zap it.
+ if (OffsetPtr && OffsetPtr != OffsetBasePtr)
+ if (Instruction *I = dyn_cast<Instruction>(OffsetPtr)) {
+ assert(I->use_empty() && "Built a GEP with uses some how!");
+ I->eraseFromParent();
+ }
+ OffsetPtr = P;
+ OffsetBasePtr = Ptr;
+ // If we also found a pointer of the right type, we're done.
+ if (P->getType() == PointerTy)
return P;
- }
- if (!OffsetPtr) {
- OffsetPtr = P;
- }
}
// Stash this pointer if we've found an i8*.
@@ -1502,18 +1790,20 @@ static Value *getAdjustedPtr(IRBuilderTy &IRB, const DataLayout &DL, Value *Ptr,
break;
}
assert(Ptr->getType()->isPointerTy() && "Unexpected operand type!");
- } while (Visited.insert(Ptr));
+ } while (Visited.insert(Ptr).second);
if (!OffsetPtr) {
if (!Int8Ptr) {
- Int8Ptr = IRB.CreateBitCast(Ptr, IRB.getInt8PtrTy(),
- NamePrefix + "sroa_raw_cast");
+ Int8Ptr = IRB.CreateBitCast(
+ Ptr, IRB.getInt8PtrTy(PointerTy->getPointerAddressSpace()),
+ NamePrefix + "sroa_raw_cast");
Int8PtrOffset = Offset;
}
- OffsetPtr = Int8PtrOffset == 0 ? Int8Ptr :
- IRB.CreateInBoundsGEP(Int8Ptr, IRB.getInt(Int8PtrOffset),
- NamePrefix + "sroa_raw_idx");
+ OffsetPtr = Int8PtrOffset == 0
+ ? Int8Ptr
+ : IRB.CreateInBoundsGEP(Int8Ptr, IRB.getInt(Int8PtrOffset),
+ NamePrefix + "sroa_raw_idx");
}
Ptr = OffsetPtr;
@@ -1524,6 +1814,27 @@ static Value *getAdjustedPtr(IRBuilderTy &IRB, const DataLayout &DL, Value *Ptr,
return Ptr;
}
+/// \brief Compute the adjusted alignment for a load or store from an offset.
+static unsigned getAdjustedAlignment(Instruction *I, uint64_t Offset,
+ const DataLayout &DL) {
+ unsigned Alignment;
+ Type *Ty;
+ if (auto *LI = dyn_cast<LoadInst>(I)) {
+ Alignment = LI->getAlignment();
+ Ty = LI->getType();
+ } else if (auto *SI = dyn_cast<StoreInst>(I)) {
+ Alignment = SI->getAlignment();
+ Ty = SI->getValueOperand()->getType();
+ } else {
+ llvm_unreachable("Only loads and stores are allowed!");
+ }
+
+ if (!Alignment)
+ Alignment = DL.getABITypeAlignment(Ty);
+
+ return MinAlign(Alignment, Offset);
+}
+
/// \brief Test whether we can convert a value from the old to the new type.
///
/// This predicate should be used to guard calls to convertValue in order to
@@ -1617,39 +1928,43 @@ static Value *convertValue(const DataLayout &DL, IRBuilderTy &IRB, Value *V,
///
/// This function is called to test each entry in a partioning which is slated
/// for a single slice.
-static bool isVectorPromotionViableForSlice(
- const DataLayout &DL, AllocaSlices &S, uint64_t SliceBeginOffset,
- uint64_t SliceEndOffset, VectorType *Ty, uint64_t ElementSize,
- AllocaSlices::const_iterator I) {
+static bool isVectorPromotionViableForSlice(AllocaSlices::Partition &P,
+ const Slice &S, VectorType *Ty,
+ uint64_t ElementSize,
+ const DataLayout &DL) {
// First validate the slice offsets.
uint64_t BeginOffset =
- std::max(I->beginOffset(), SliceBeginOffset) - SliceBeginOffset;
+ std::max(S.beginOffset(), P.beginOffset()) - P.beginOffset();
uint64_t BeginIndex = BeginOffset / ElementSize;
if (BeginIndex * ElementSize != BeginOffset ||
BeginIndex >= Ty->getNumElements())
return false;
uint64_t EndOffset =
- std::min(I->endOffset(), SliceEndOffset) - SliceBeginOffset;
+ std::min(S.endOffset(), P.endOffset()) - P.beginOffset();
uint64_t EndIndex = EndOffset / ElementSize;
if (EndIndex * ElementSize != EndOffset || EndIndex > Ty->getNumElements())
return false;
assert(EndIndex > BeginIndex && "Empty vector!");
uint64_t NumElements = EndIndex - BeginIndex;
- Type *SliceTy =
- (NumElements == 1) ? Ty->getElementType()
- : VectorType::get(Ty->getElementType(), NumElements);
+ Type *SliceTy = (NumElements == 1)
+ ? Ty->getElementType()
+ : VectorType::get(Ty->getElementType(), NumElements);
Type *SplitIntTy =
Type::getIntNTy(Ty->getContext(), NumElements * ElementSize * 8);
- Use *U = I->getUse();
+ Use *U = S.getUse();
if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
if (MI->isVolatile())
return false;
- if (!I->isSplittable())
+ if (!S.isSplittable())
return false; // Skip any unsplittable intrinsics.
+ } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U->getUser())) {
+ if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
+ II->getIntrinsicID() != Intrinsic::lifetime_end)
+ return false;
} else if (U->get()->getType()->getPointerElementType()->isStructTy()) {
// Disable vector promotion when there are loads or stores of an FCA.
return false;
if (LI->isVolatile())
return false;
Type *LTy = LI->getType();
- if (SliceBeginOffset > I->beginOffset() ||
- SliceEndOffset < I->endOffset()) {
+ if (P.beginOffset() > S.beginOffset() || P.endOffset() < S.endOffset()) {
assert(LTy->isIntegerTy());
LTy = SplitIntTy;
}
if (SI->isVolatile())
return false;
Type *STy = SI->getValueOperand()->getType();
- if (SliceBeginOffset > I->beginOffset() ||
- SliceEndOffset < I->endOffset()) {
+ if (P.beginOffset() > S.beginOffset() || P.endOffset() < S.endOffset()) {
assert(STy->isIntegerTy());
STy = SplitIntTy;
}
/// 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 DataLayout &DL, Type *AllocaTy, AllocaSlices &S,
- uint64_t SliceBeginOffset, uint64_t SliceEndOffset,
- AllocaSlices::const_iterator I,
- AllocaSlices::const_iterator E,
- ArrayRef<AllocaSlices::iterator> SplitUses) {
- VectorType *Ty = dyn_cast<VectorType>(AllocaTy);
- if (!Ty)
- return false;
+static VectorType *isVectorPromotionViable(AllocaSlices::Partition &P,
+ const DataLayout &DL) {
+ // Collect the candidate types for vector-based promotion. Also track whether
+ // we have different element types.
+ SmallVector<VectorType *, 4> CandidateTys;
+ Type *CommonEltTy = nullptr;
+ bool HaveCommonEltTy = true;
+ auto CheckCandidateType = [&](Type *Ty) {
+ if (auto *VTy = dyn_cast<VectorType>(Ty)) {
+ CandidateTys.push_back(VTy);
+ if (!CommonEltTy)
+ CommonEltTy = VTy->getElementType();
+ else if (CommonEltTy != VTy->getElementType())
+ HaveCommonEltTy = false;
+ }
+ };
+ // Consider any loads or stores that are the exact size of the slice.
+ for (const Slice &S : P)
+ if (S.beginOffset() == P.beginOffset() &&
+ S.endOffset() == P.endOffset()) {
+ if (auto *LI = dyn_cast<LoadInst>(S.getUse()->getUser()))
+ CheckCandidateType(LI->getType());
+ else if (auto *SI = dyn_cast<StoreInst>(S.getUse()->getUser()))
+ CheckCandidateType(SI->getValueOperand()->getType());
+ }
- uint64_t ElementSize = DL.getTypeSizeInBits(Ty->getScalarType());
+ // If we didn't find a vector type, nothing to do here.
+ if (CandidateTys.empty())
+ return nullptr;
+
+ // Remove non-integer vector types if we had multiple common element types.
+ // FIXME: It'd be nice to replace them with integer vector types, but we can't
+ // do that until all the backends are known to produce good code for all
+ // integer vector types.
+ if (!HaveCommonEltTy) {
+ CandidateTys.erase(std::remove_if(CandidateTys.begin(), CandidateTys.end(),
+ [](VectorType *VTy) {
+ return !VTy->getElementType()->isIntegerTy();
+ }),
+ CandidateTys.end());
+
+ // If there were no integer vector types, give up.
+ if (CandidateTys.empty())
+ return nullptr;
+
+ // Rank the remaining candidate vector types. This is easy because we know
+ // they're all integer vectors. We sort by ascending number of elements.
+ auto RankVectorTypes = [&DL](VectorType *RHSTy, VectorType *LHSTy) {
+ assert(DL.getTypeSizeInBits(RHSTy) == DL.getTypeSizeInBits(LHSTy) &&
+ "Cannot have vector types of different sizes!");
+ assert(RHSTy->getElementType()->isIntegerTy() &&
+ "All non-integer types eliminated!");
+ assert(LHSTy->getElementType()->isIntegerTy() &&
+ "All non-integer types eliminated!");
+ return RHSTy->getNumElements() < LHSTy->getNumElements();
+ };
+ std::sort(CandidateTys.begin(), CandidateTys.end(), RankVectorTypes);
+ CandidateTys.erase(
+ std::unique(CandidateTys.begin(), CandidateTys.end(), RankVectorTypes),
+ CandidateTys.end());
+ } else {
+// The only way to have the same element type in every vector type is to
+// have the same vector type. Check that and remove all but one.
+#ifndef NDEBUG
+ for (VectorType *VTy : CandidateTys) {
+ assert(VTy->getElementType() == CommonEltTy &&
+ "Unaccounted for element type!");
+ assert(VTy == CandidateTys[0] &&
+ "Different vector types with the same element type!");
+ }
+#endif
+ CandidateTys.resize(1);
+ }
- // While the definition of LLVM vectors is bitpacked, we don't support sizes
- // that aren't byte sized.
- if (ElementSize % 8)
- return false;
- assert((DL.getTypeSizeInBits(Ty) % 8) == 0 &&
- "vector size not a multiple of element size?");
- ElementSize /= 8;
+ // Try each vector type, and return the one which works.
+ auto CheckVectorTypeForPromotion = [&](VectorType *VTy) {
+ uint64_t ElementSize = DL.getTypeSizeInBits(VTy->getElementType());
- for (; I != E; ++I)
- if (!isVectorPromotionViableForSlice(DL, S, SliceBeginOffset,
- SliceEndOffset, Ty, ElementSize, I))
+ // While the definition of LLVM vectors is bitpacked, we don't support sizes
+ // that aren't byte sized.
+ if (ElementSize % 8)
return false;
+ assert((DL.getTypeSizeInBits(VTy) % 8) == 0 &&
+ "vector size not a multiple of element size?");
+ ElementSize /= 8;
- for (ArrayRef<AllocaSlices::iterator>::const_iterator SUI = SplitUses.begin(),
- SUE = SplitUses.end();
- SUI != SUE; ++SUI)
- if (!isVectorPromotionViableForSlice(DL, S, SliceBeginOffset,
- SliceEndOffset, Ty, ElementSize, *SUI))
- return false;
+ for (const Slice &S : P)
+ if (!isVectorPromotionViableForSlice(P, S, VTy, ElementSize, DL))
+ return false;
- return true;
+ for (const Slice *S : P.splitSliceTails())
+ if (!isVectorPromotionViableForSlice(P, *S, VTy, ElementSize, DL))
+ return false;
+
+ return true;
+ };
+ for (VectorType *VTy : CandidateTys)
+ if (CheckVectorTypeForPromotion(VTy))
+ return VTy;
+
+ return nullptr;
}
/// \brief Test whether a slice of an alloca is valid for integer widening.
///
/// This implements the necessary checking for the \c isIntegerWideningViable
/// test below on a single slice of the alloca.
-static bool isIntegerWideningViableForSlice(const DataLayout &DL,
- Type *AllocaTy,
+static bool isIntegerWideningViableForSlice(const Slice &S,
uint64_t AllocBeginOffset,
- uint64_t Size, AllocaSlices &S,
- AllocaSlices::const_iterator I,
+ Type *AllocaTy,
+ const DataLayout &DL,
bool &WholeAllocaOp) {
- uint64_t RelBegin = I->beginOffset() - AllocBeginOffset;
- uint64_t RelEnd = I->endOffset() - AllocBeginOffset;
+ uint64_t Size = DL.getTypeStoreSize(AllocaTy);
+
+ uint64_t RelBegin = S.beginOffset() - AllocBeginOffset;
+ uint64_t RelEnd = S.endOffset() - AllocBeginOffset;
// We can't reasonably handle cases where the load or store extends past
// the end of the aloca's type and into its padding.
if (RelEnd > Size)
return false;
- Use *U = I->getUse();
+ Use *U = S.getUse();
if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
if (LI->isVolatile())
return false;
- if (RelBegin == 0 && RelEnd == Size)
+ // Note that we don't count vector loads or stores as whole-alloca
+ // operations which enable integer widening because we would prefer to use
+ // vector widening instead.
+ if (!isa<VectorType>(LI->getType()) && RelBegin == 0 && RelEnd == Size)
WholeAllocaOp = true;
if (IntegerType *ITy = dyn_cast<IntegerType>(LI->getType())) {
if (ITy->getBitWidth() < DL.getTypeStoreSizeInBits(ITy))
Type *ValueTy = SI->getValueOperand()->getType();
if (SI->isVolatile())
return false;
- if (RelBegin == 0 && RelEnd == Size)
+ // Note that we don't count vector loads or stores as whole-alloca
+ // operations which enable integer widening because we would prefer to use
+ // vector widening instead.
+ if (!isa<VectorType>(ValueTy) && RelBegin == 0 && RelEnd == Size)
WholeAllocaOp = true;
if (IntegerType *ITy = dyn_cast<IntegerType>(ValueTy)) {
if (ITy->getBitWidth() < DL.getTypeStoreSizeInBits(ITy))
} else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
if (MI->isVolatile() || !isa<Constant>(MI->getLength()))
return false;
- if (!I->isSplittable())
+ if (!S.isSplittable())
return false; // Skip any unsplittable intrinsics.
} else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U->getUser())) {
if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
/// This is a quick test to check whether we can rewrite the integer loads and
/// stores to a particular alloca into wider loads and stores and be able to
/// promote the resulting alloca.
-static bool
-isIntegerWideningViable(const DataLayout &DL, Type *AllocaTy,
- uint64_t AllocBeginOffset, AllocaSlices &S,
- AllocaSlices::const_iterator I,
- AllocaSlices::const_iterator E,
- ArrayRef<AllocaSlices::iterator> SplitUses) {
+static bool isIntegerWideningViable(AllocaSlices::Partition &P, Type *AllocaTy,
+ const DataLayout &DL) {
uint64_t SizeInBits = DL.getTypeSizeInBits(AllocaTy);
// Don't create integer types larger than the maximum bitwidth.
if (SizeInBits > IntegerType::MAX_INT_BITS)
!canConvertValue(DL, IntTy, AllocaTy))
return false;
- uint64_t Size = DL.getTypeStoreSize(AllocaTy);
-
// While examining uses, we ensure that the alloca has a covering load or
// store. We don't want to widen the integer operations only to fail to
// promote due to some other unsplittable entry (which we may make splittable
// later). However, if there are only splittable uses, go ahead and assume
// that we cover the alloca.
- bool WholeAllocaOp = (I != E) ? false : DL.isLegalInteger(SizeInBits);
-
- for (; I != E; ++I)
- if (!isIntegerWideningViableForSlice(DL, AllocaTy, AllocBeginOffset, Size,
- S, I, WholeAllocaOp))
+ // FIXME: We shouldn't consider split slices that happen to start in the
+ // partition here...
+ bool WholeAllocaOp =
+ P.begin() != P.end() ? false : DL.isLegalInteger(SizeInBits);
+
+ for (const Slice &S : P)
+ if (!isIntegerWideningViableForSlice(S, P.beginOffset(), AllocaTy, DL,
+ WholeAllocaOp))
return false;
- for (ArrayRef<AllocaSlices::iterator>::const_iterator SUI = SplitUses.begin(),
- SUE = SplitUses.end();
- SUI != SUE; ++SUI)
- if (!isIntegerWideningViableForSlice(DL, AllocaTy, AllocBeginOffset, Size,
- S, *SUI, WholeAllocaOp))
+ for (const Slice *S : P.splitSliceTails())
+ if (!isIntegerWideningViableForSlice(*S, P.beginOffset(), AllocaTy, DL,
+ WholeAllocaOp))
return false;
return WholeAllocaOp;
@@ -1851,9 +2234,9 @@ static Value *extractInteger(const DataLayout &DL, IRBuilderTy &IRB, Value *V,
IntegerType *IntTy = cast<IntegerType>(V->getType());
assert(DL.getTypeStoreSize(Ty) + Offset <= DL.getTypeStoreSize(IntTy) &&
"Element extends past full value");
- uint64_t ShAmt = 8*Offset;
+ uint64_t ShAmt = 8 * Offset;
if (DL.isBigEndian())
- ShAmt = 8*(DL.getTypeStoreSize(IntTy) - DL.getTypeStoreSize(Ty) - Offset);
+ ShAmt = 8 * (DL.getTypeStoreSize(IntTy) - DL.getTypeStoreSize(Ty) - Offset);
if (ShAmt) {
V = IRB.CreateLShr(V, ShAmt, Name + ".shift");
DEBUG(dbgs() << " shifted: " << *V << "\n");
@@ -1880,9 +2263,9 @@ static Value *insertInteger(const DataLayout &DL, IRBuilderTy &IRB, Value *Old,
}
assert(DL.getTypeStoreSize(Ty) + Offset <= DL.getTypeStoreSize(IntTy) &&
"Element store outside of alloca store");
- uint64_t ShAmt = 8*Offset;
+ uint64_t ShAmt = 8 * Offset;
if (DL.isBigEndian())
- ShAmt = 8*(DL.getTypeStoreSize(IntTy) - DL.getTypeStoreSize(Ty) - Offset);
+ ShAmt = 8 * (DL.getTypeStoreSize(IntTy) - DL.getTypeStoreSize(Ty) - Offset);
if (ShAmt) {
V = IRB.CreateShl(V, ShAmt, Name + ".shift");
DEBUG(dbgs() << " shifted: " << *V << "\n");
@@ -1898,9 +2281,8 @@ static Value *insertInteger(const DataLayout &DL, IRBuilderTy &IRB, Value *Old,
return V;
}
-static Value *extractVector(IRBuilderTy &IRB, Value *V,
- unsigned BeginIndex, unsigned EndIndex,
- const Twine &Name) {
+static Value *extractVector(IRBuilderTy &IRB, Value *V, unsigned BeginIndex,
+ unsigned EndIndex, const Twine &Name) {
VectorType *VecTy = cast<VectorType>(V->getType());
unsigned NumElements = EndIndex - BeginIndex;
assert(NumElements <= VecTy->getNumElements() && "Too many elements!");
return V;
}
- SmallVector<Constant*, 8> Mask;
+ SmallVector<Constant *, 8> Mask;
Mask.reserve(NumElements);
for (unsigned i = BeginIndex; i != EndIndex; ++i)
Mask.push_back(IRB.getInt32(i));
V = IRB.CreateShuffleVector(V, UndefValue::get(V->getType()),
- ConstantVector::get(Mask),
- Name + ".extract");
+ ConstantVector::get(Mask), Name + ".extract");
DEBUG(dbgs() << " shuffle: " << *V << "\n");
return V;
}
// Single element to insert.
V = IRB.CreateInsertElement(Old, V, IRB.getInt32(BeginIndex),
Name + ".insert");
- DEBUG(dbgs() << " insert: " << *V << "\n");
+ DEBUG(dbgs() << " insert: " << *V << "\n");
return V;
}
// use a shuffle vector to widen it with undef elements, and then
// a second shuffle vector to select between the loaded vector and the
// incoming vector.
- SmallVector<Constant*, 8> Mask;
+ SmallVector<Constant *, 8> Mask;
Mask.reserve(VecTy->getNumElements());
for (unsigned i = 0; i != VecTy->getNumElements(); ++i)
if (i >= BeginIndex && i < EndIndex)
else
Mask.push_back(UndefValue::get(IRB.getInt32Ty()));
V = IRB.CreateShuffleVector(V, UndefValue::get(V->getType()),
- ConstantVector::get(Mask),
- Name + ".expand");
+ ConstantVector::get(Mask), Name + ".expand");
DEBUG(dbgs() << " shuffle: " << *V << "\n");
Mask.clear();
typedef llvm::InstVisitor<AllocaSliceRewriter, bool> Base;
const DataLayout &DL;
- AllocaSlices &S;
+ AllocaSlices &AS;
SROA &Pass;
AllocaInst &OldAI, &NewAI;
const uint64_t NewAllocaBeginOffset, NewAllocaEndOffset;
Type *NewAllocaTy;
+ // This is a convenience and flag variable that will be null unless the new
+ // alloca's integer operations should be widened to this integer type due to
+ // passing isIntegerWideningViable above. If it is non-null, the desired
+ // integer type will be stored here for easy access during rewriting.
+ IntegerType *IntTy;
+
// 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 rewritten alloca:
Type *ElementTy;
uint64_t ElementSize;
- // This is a convenience and flag variable that will be null unless the new
- // alloca's integer operations should be widened to this integer type due to
- // passing isIntegerWideningViable above. If it is non-null, the desired
- // integer type will be stored here for easy access during rewriting.
- IntegerType *IntTy;
-
- // The offset of the slice currently being rewritten.
+ // The original offset of the slice currently being rewritten relative to
+ // the original alloca.
uint64_t BeginOffset, EndOffset;
+ // The new offsets of the slice currently being rewritten relative to the
+ // original alloca.
+ uint64_t NewBeginOffset, NewEndOffset;
+
+ uint64_t SliceSize;
bool IsSplittable;
bool IsSplit;
Use *OldUse;
IRBuilderTy IRB;
public:
- AllocaSliceRewriter(const DataLayout &DL, AllocaSlices &S, SROA &Pass,
+ AllocaSliceRewriter(const DataLayout &DL, AllocaSlices &AS, SROA &Pass,
AllocaInst &OldAI, AllocaInst &NewAI,
- uint64_t NewBeginOffset, uint64_t NewEndOffset,
- bool IsVectorPromotable, bool IsIntegerPromotable,
+ uint64_t NewAllocaBeginOffset,
+ uint64_t NewAllocaEndOffset, bool IsIntegerPromotable,
+ VectorType *PromotableVecTy,
SmallPtrSetImpl<PHINode *> &PHIUsers,
SmallPtrSetImpl<SelectInst *> &SelectUsers)
- : DL(DL), S(S), Pass(Pass), OldAI(OldAI), NewAI(NewAI),
- NewAllocaBeginOffset(NewBeginOffset), NewAllocaEndOffset(NewEndOffset),
+ : DL(DL), AS(AS), Pass(Pass), OldAI(OldAI), NewAI(NewAI),
+ NewAllocaBeginOffset(NewAllocaBeginOffset),
+ NewAllocaEndOffset(NewAllocaEndOffset),
NewAllocaTy(NewAI.getAllocatedType()),
- VecTy(IsVectorPromotable ? cast<VectorType>(NewAllocaTy) : 0),
- ElementTy(VecTy ? VecTy->getElementType() : 0),
- ElementSize(VecTy ? DL.getTypeSizeInBits(ElementTy) / 8 : 0),
IntTy(IsIntegerPromotable
? Type::getIntNTy(
NewAI.getContext(),
DL.getTypeSizeInBits(NewAI.getAllocatedType()))
- : 0),
+ : nullptr),
+ VecTy(PromotableVecTy),
+ ElementTy(VecTy ? VecTy->getElementType() : nullptr),
+ ElementSize(VecTy ? DL.getTypeSizeInBits(ElementTy) / 8 : 0),
BeginOffset(), EndOffset(), IsSplittable(), IsSplit(), OldUse(),
OldPtr(), PHIUsers(PHIUsers), SelectUsers(SelectUsers),
IRB(NewAI.getContext(), ConstantFolder()) {
"Only multiple-of-8 sized vector elements are viable");
++NumVectorized;
}
- assert((!IsVectorPromotable && !IsIntegerPromotable) ||
- IsVectorPromotable != IsIntegerPromotable);
+ assert((!IntTy && !VecTy) || (IntTy && !VecTy) || (!IntTy && VecTy));
}
bool visit(AllocaSlices::const_iterator I) {
IsSplittable = I->isSplittable();
IsSplit =
BeginOffset < NewAllocaBeginOffset || EndOffset > NewAllocaEndOffset;
+ DEBUG(dbgs() << " rewriting " << (IsSplit ? "split " : ""));
+ DEBUG(AS.printSlice(dbgs(), I, ""));
+ DEBUG(dbgs() << "\n");
+
+ // Compute the intersecting offset range.
+ assert(BeginOffset < NewAllocaEndOffset);
+ assert(EndOffset > NewAllocaBeginOffset);
+ NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
+ NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
+
+ SliceSize = NewEndOffset - NewBeginOffset;
OldUse = I->getUse();
OldPtr = cast<Instruction>(OldUse->get());
llvm_unreachable("No rewrite rule for this instruction!");
}
- Value *getAdjustedAllocaPtr(IRBuilderTy &IRB, uint64_t Offset,
- Type *PointerTy) {
- assert(Offset >= NewAllocaBeginOffset);
+ Value *getNewAllocaSlicePtr(IRBuilderTy &IRB, Type *PointerTy) {
+ // Note that the offset computation can use BeginOffset or NewBeginOffset
+ // interchangeably for unsplit slices.
+ assert(IsSplit || BeginOffset == NewBeginOffset);
+ uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
+
#ifndef NDEBUG
StringRef OldName = OldPtr->getName();
// Skip through the last '.sroa.' component of the name.
// Strip any SROA suffixes as well.
OldName = OldName.substr(0, OldName.find(".sroa_"));
#endif
- return getAdjustedPtr(IRB, DL, &NewAI, APInt(DL.getPointerSizeInBits(),
- Offset - NewAllocaBeginOffset),
- PointerTy,
+
+ return getAdjustedPtr(IRB, DL, &NewAI,
+ APInt(DL.getPointerSizeInBits(), Offset), PointerTy,
#ifndef NDEBUG
Twine(OldName) + "."
#else
);
}
- /// \brief Compute suitable alignment to access an offset into the new alloca.
- unsigned getOffsetAlign(uint64_t Offset) {
+ /// \brief Compute suitable alignment to access this slice of the *new*
+ /// alloca.
+ ///
+ /// You can optionally pass a type to this routine and if that type's ABI
+ /// alignment is itself suitable, this will return zero.
+ unsigned getSliceAlign(Type *Ty = nullptr) {
unsigned NewAIAlign = NewAI.getAlignment();
if (!NewAIAlign)
NewAIAlign = DL.getABITypeAlignment(NewAI.getAllocatedType());
- return MinAlign(NewAIAlign, Offset);
- }
-
- /// \brief Compute suitable alignment to access a type at an offset of the
- /// new alloca.
- ///
- /// \returns zero if the type's ABI alignment is a suitable alignment,
- /// otherwise returns the maximal suitable alignment.
- unsigned getOffsetTypeAlign(Type *Ty, uint64_t Offset) {
- unsigned Align = getOffsetAlign(Offset);
- return Align == DL.getABITypeAlignment(Ty) ? 0 : Align;
+ unsigned Align =
+ MinAlign(NewAIAlign, NewBeginOffset - NewAllocaBeginOffset);
+ return (Ty && Align == DL.getABITypeAlignment(Ty)) ? 0 : Align;
}
unsigned getIndex(uint64_t Offset) {
Pass.DeadInsts.insert(I);
}
- Value *rewriteVectorizedLoadInst(uint64_t NewBeginOffset,
- uint64_t NewEndOffset) {
+ Value *rewriteVectorizedLoadInst() {
unsigned BeginIndex = getIndex(NewBeginOffset);
unsigned EndIndex = getIndex(NewEndOffset);
assert(EndIndex > BeginIndex && "Empty vector!");
- Value *V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "load");
+ Value *V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "load");
return extractVector(IRB, V, BeginIndex, EndIndex, "vec");
}
- Value *rewriteIntegerLoad(LoadInst &LI, uint64_t NewBeginOffset,
- uint64_t NewEndOffset) {
+ Value *rewriteIntegerLoad(LoadInst &LI) {
assert(IntTy && "We cannot insert an integer to the alloca");
assert(!LI.isVolatile());
- Value *V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "load");
+ Value *V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "load");
V = convertValue(DL, IRB, V, IntTy);
assert(NewBeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
Value *OldOp = LI.getOperand(0);
assert(OldOp == OldPtr);
- // Compute the intersecting offset range.
- assert(BeginOffset < NewAllocaEndOffset);
- assert(EndOffset > NewAllocaBeginOffset);
- uint64_t NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
- uint64_t NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
-
- uint64_t Size = NewEndOffset - NewBeginOffset;
-
- Type *TargetTy = IsSplit ? Type::getIntNTy(LI.getContext(), Size * 8)
+ Type *TargetTy = IsSplit ? Type::getIntNTy(LI.getContext(), SliceSize * 8)
: LI.getType();
bool IsPtrAdjusted = false;
Value *V;
if (VecTy) {
- V = rewriteVectorizedLoadInst(NewBeginOffset, NewEndOffset);
+ V = rewriteVectorizedLoadInst();
} else if (IntTy && LI.getType()->isIntegerTy()) {
- V = rewriteIntegerLoad(LI, NewBeginOffset, NewEndOffset);
+ V = rewriteIntegerLoad(LI);
} else if (NewBeginOffset == NewAllocaBeginOffset &&
canConvertValue(DL, NewAllocaTy, LI.getType())) {
- V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- LI.isVolatile(), LI.getName());
+ V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), LI.isVolatile(),
+ LI.getName());
} else {
Type *LTy = TargetTy->getPointerTo();
- V = IRB.CreateAlignedLoad(
- getAdjustedAllocaPtr(IRB, NewBeginOffset, LTy),
- getOffsetTypeAlign(TargetTy, NewBeginOffset - NewAllocaBeginOffset),
- LI.isVolatile(), LI.getName());
+ V = IRB.CreateAlignedLoad(getNewAllocaSlicePtr(IRB, LTy),
+ getSliceAlign(TargetTy), LI.isVolatile(),
+ LI.getName());
IsPtrAdjusted = true;
}
V = convertValue(DL, IRB, V, TargetTy);
assert(!LI.isVolatile());
assert(LI.getType()->isIntegerTy() &&
"Only integer type loads and stores are split");
- assert(Size < DL.getTypeStoreSize(LI.getType()) &&
+ assert(SliceSize < DL.getTypeStoreSize(LI.getType()) &&
"Split load isn't smaller than original load");
assert(LI.getType()->getIntegerBitWidth() ==
- DL.getTypeStoreSizeInBits(LI.getType()) &&
+ DL.getTypeStoreSizeInBits(LI.getType()) &&
"Non-byte-multiple bit width");
// Move the insertion point just past the load so that we can refer to it.
- IRB.SetInsertPoint(llvm::next(BasicBlock::iterator(&LI)));
+ IRB.SetInsertPoint(std::next(BasicBlock::iterator(&LI)));
// Create a placeholder value with the same type as LI to use as the
// basis for the new value. This allows us to replace the uses of LI with
// the computed value, and then replace the placeholder with LI, leaving
// LI only used for this computation.
- Value *Placeholder
- = new LoadInst(UndefValue::get(LI.getType()->getPointerTo()));
- V = insertInteger(DL, IRB, Placeholder, V, NewBeginOffset,
+ Value *Placeholder =
+ new LoadInst(UndefValue::get(LI.getType()->getPointerTo()));
+ V = insertInteger(DL, IRB, Placeholder, V, NewBeginOffset - BeginOffset,
"insert");
LI.replaceAllUsesWith(V);
Placeholder->replaceAllUsesWith(&LI);
return !LI.isVolatile() && !IsPtrAdjusted;
}
- bool rewriteVectorizedStoreInst(Value *V, StoreInst &SI, Value *OldOp,
- uint64_t NewBeginOffset,
- uint64_t NewEndOffset) {
+ bool rewriteVectorizedStoreInst(Value *V, StoreInst &SI, Value *OldOp) {
if (V->getType() != VecTy) {
unsigned BeginIndex = getIndex(NewBeginOffset);
unsigned EndIndex = getIndex(NewEndOffset);
assert(EndIndex > BeginIndex && "Empty vector!");
unsigned NumElements = EndIndex - BeginIndex;
assert(NumElements <= VecTy->getNumElements() && "Too many elements!");
- Type *SliceTy =
- (NumElements == 1) ? ElementTy
- : VectorType::get(ElementTy, NumElements);
+ Type *SliceTy = (NumElements == 1)
+ ? ElementTy
+ : VectorType::get(ElementTy, NumElements);
if (V->getType() != SliceTy)
V = convertValue(DL, IRB, V, SliceTy);
// Mix in the existing elements.
- Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "load");
+ Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "load");
V = insertVector(IRB, Old, V, BeginIndex, "vec");
}
StoreInst *Store = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlignment());
return true;
}
- bool rewriteIntegerStore(Value *V, StoreInst &SI,
- uint64_t NewBeginOffset, uint64_t NewEndOffset) {
+ bool rewriteIntegerStore(Value *V, StoreInst &SI) {
assert(IntTy && "We cannot extract an integer from the alloca");
assert(!SI.isVolatile());
if (DL.getTypeSizeInBits(V->getType()) != IntTy->getBitWidth()) {
- Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "oldload");
+ Value *Old =
+ IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "oldload");
Old = convertValue(DL, IRB, Old, IntTy);
assert(BeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
uint64_t Offset = BeginOffset - NewAllocaBeginOffset;
- V = insertInteger(DL, IRB, Old, SI.getValueOperand(), Offset,
- "insert");
+ V = insertInteger(DL, IRB, Old, SI.getValueOperand(), Offset, "insert");
}
V = convertValue(DL, IRB, V, NewAllocaTy);
StoreInst *Store = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlignment());
if (AllocaInst *AI = dyn_cast<AllocaInst>(V->stripInBoundsOffsets()))
Pass.PostPromotionWorklist.insert(AI);
- // Compute the intersecting offset range.
- assert(BeginOffset < NewAllocaEndOffset);
- assert(EndOffset > NewAllocaBeginOffset);
- uint64_t NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
- uint64_t NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
-
- uint64_t Size = NewEndOffset - NewBeginOffset;
- if (Size < DL.getTypeStoreSize(V->getType())) {
+ if (SliceSize < DL.getTypeStoreSize(V->getType())) {
assert(!SI.isVolatile());
assert(V->getType()->isIntegerTy() &&
"Only integer type loads and stores are split");
assert(V->getType()->getIntegerBitWidth() ==
- DL.getTypeStoreSizeInBits(V->getType()) &&
+ DL.getTypeStoreSizeInBits(V->getType()) &&
"Non-byte-multiple bit width");
- IntegerType *NarrowTy = Type::getIntNTy(SI.getContext(), Size * 8);
- V = extractInteger(DL, IRB, V, NarrowTy, NewBeginOffset,
+ IntegerType *NarrowTy = Type::getIntNTy(SI.getContext(), SliceSize * 8);
+ V = extractInteger(DL, IRB, V, NarrowTy, NewBeginOffset - BeginOffset,
"extract");
}
if (VecTy)
- return rewriteVectorizedStoreInst(V, SI, OldOp, NewBeginOffset,
- NewEndOffset);
+ return rewriteVectorizedStoreInst(V, SI, OldOp);
if (IntTy && V->getType()->isIntegerTy())
- return rewriteIntegerStore(V, SI, NewBeginOffset, NewEndOffset);
+ return rewriteIntegerStore(V, SI);
StoreInst *NewSI;
if (NewBeginOffset == NewAllocaBeginOffset &&
NewSI = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlignment(),
SI.isVolatile());
} else {
- Value *NewPtr = getAdjustedAllocaPtr(IRB, NewBeginOffset,
- V->getType()->getPointerTo());
- NewSI = IRB.CreateAlignedStore(
- V, NewPtr, getOffsetTypeAlign(V->getType(),
- NewBeginOffset - NewAllocaBeginOffset),
- SI.isVolatile());
+ Value *NewPtr = getNewAllocaSlicePtr(IRB, V->getType()->getPointerTo());
+ NewSI = IRB.CreateAlignedStore(V, NewPtr, getSliceAlign(V->getType()),
+ SI.isVolatile());
}
(void)NewSI;
Pass.DeadInsts.insert(&SI);
if (Size == 1)
return V;
- Type *SplatIntTy = Type::getIntNTy(VTy->getContext(), Size*8);
- V = IRB.CreateMul(IRB.CreateZExt(V, SplatIntTy, "zext"),
- ConstantExpr::getUDiv(
- Constant::getAllOnesValue(SplatIntTy),
- ConstantExpr::getZExt(
- Constant::getAllOnesValue(V->getType()),
- SplatIntTy)),
- "isplat");
+ Type *SplatIntTy = Type::getIntNTy(VTy->getContext(), Size * 8);
+ V = IRB.CreateMul(
+ IRB.CreateZExt(V, SplatIntTy, "zext"),
+ ConstantExpr::getUDiv(
+ Constant::getAllOnesValue(SplatIntTy),
+ ConstantExpr::getZExt(Constant::getAllOnesValue(V->getType()),
+ SplatIntTy)),
+ "isplat");
return V;
}
// pointer to the new alloca.
if (!isa<Constant>(II.getLength())) {
assert(!IsSplit);
- assert(BeginOffset >= NewAllocaBeginOffset);
- II.setDest(getAdjustedAllocaPtr(IRB, BeginOffset, OldPtr->getType()));
+ assert(NewBeginOffset == BeginOffset);
+ II.setDest(getNewAllocaSlicePtr(IRB, OldPtr->getType()));
Type *CstTy = II.getAlignmentCst()->getType();
- II.setAlignment(ConstantInt::get(CstTy, getOffsetAlign(BeginOffset)));
+ II.setAlignment(ConstantInt::get(CstTy, getSliceAlign()));
deleteIfTriviallyDead(OldPtr);
return false;
Type *AllocaTy = NewAI.getAllocatedType();
Type *ScalarTy = AllocaTy->getScalarType();
- // Compute the intersecting offset range.
- assert(BeginOffset < NewAllocaEndOffset);
- assert(EndOffset > NewAllocaBeginOffset);
- uint64_t NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
- uint64_t NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
- uint64_t SliceOffset = NewBeginOffset - NewAllocaBeginOffset;
-
// 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 && !IntTy &&
- (BeginOffset > NewAllocaBeginOffset ||
- EndOffset < NewAllocaEndOffset ||
+ (BeginOffset > NewAllocaBeginOffset || EndOffset < NewAllocaEndOffset ||
+ SliceSize != DL.getTypeStoreSize(AllocaTy) ||
!AllocaTy->isSingleValueType() ||
!DL.isLegalInteger(DL.getTypeSizeInBits(ScalarTy)) ||
- DL.getTypeSizeInBits(ScalarTy)%8 != 0)) {
+ DL.getTypeSizeInBits(ScalarTy) % 8 != 0)) {
Type *SizeTy = II.getLength()->getType();
Constant *Size = ConstantInt::get(SizeTy, NewEndOffset - NewBeginOffset);
CallInst *New = IRB.CreateMemSet(
- getAdjustedAllocaPtr(IRB, NewBeginOffset, OldPtr->getType()),
- II.getValue(), Size, getOffsetAlign(SliceOffset), II.isVolatile());
+ getNewAllocaSlicePtr(IRB, OldPtr->getType()), II.getValue(), Size,
+ getSliceAlign(), II.isVolatile());
(void)New;
DEBUG(dbgs() << " to: " << *New << "\n");
return false;
if (NumElements > 1)
Splat = getVectorSplat(Splat, NumElements);
- Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "oldload");
+ Value *Old =
+ IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "oldload");
V = insertVector(IRB, Old, Splat, BeginIndex, "vec");
} else if (IntTy) {
// If this is a memset on an alloca where we can widen stores, insert the
if (IntTy && (BeginOffset != NewAllocaBeginOffset ||
EndOffset != NewAllocaBeginOffset)) {
- Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "oldload");
+ Value *Old =
+ IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "oldload");
Old = convertValue(DL, IRB, Old, IntTy);
uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
V = insertInteger(DL, IRB, Old, V, Offset, "insert");
DEBUG(dbgs() << " original: " << II << "\n");
- // Compute the intersecting offset range.
- assert(BeginOffset < NewAllocaEndOffset);
- assert(EndOffset > NewAllocaBeginOffset);
- uint64_t NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
- uint64_t NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
-
bool IsDest = &II.getRawDestUse() == OldUse;
assert((IsDest && II.getRawDest() == OldPtr) ||
(!IsDest && II.getRawSource() == OldPtr));
- // Compute the relative offset within the transfer.
- unsigned IntPtrWidth = DL.getPointerSizeInBits();
- APInt RelOffset(IntPtrWidth, NewBeginOffset - BeginOffset);
-
- unsigned Align = II.getAlignment();
- uint64_t SliceOffset = NewBeginOffset - NewAllocaBeginOffset;
- if (Align > 1)
- Align =
- MinAlign(RelOffset.zextOrTrunc(64).getZExtValue(),
- MinAlign(II.getAlignment(), getOffsetAlign(SliceOffset)));
+ unsigned SliceAlign = getSliceAlign();
// For unsplit intrinsics, we simply modify the source and destination
// pointers in place. This isn't just an optimization, it is a matter of
// memcpy, and so simply updating the pointers is the necessary for us to
// update both source and dest of a single call.
if (!IsSplittable) {
- Value *AdjustedPtr =
- getAdjustedAllocaPtr(IRB, BeginOffset, OldPtr->getType());
+ Value *AdjustedPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
if (IsDest)
II.setDest(AdjustedPtr);
else
II.setSource(AdjustedPtr);
- Type *CstTy = II.getAlignmentCst()->getType();
- II.setAlignment(ConstantInt::get(CstTy, Align));
+ if (II.getAlignment() > SliceAlign) {
+ Type *CstTy = II.getAlignmentCst()->getType();
+ II.setAlignment(
+ ConstantInt::get(CstTy, MinAlign(II.getAlignment(), SliceAlign)));
+ }
DEBUG(dbgs() << " to: " << II << "\n");
deleteIfTriviallyDead(OldPtr);
// 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 && !IntTy && (BeginOffset > NewAllocaBeginOffset ||
- EndOffset < NewAllocaEndOffset ||
- !NewAI.getAllocatedType()->isSingleValueType());
+ bool EmitMemCpy =
+ !VecTy && !IntTy &&
+ (BeginOffset > NewAllocaBeginOffset || EndOffset < NewAllocaEndOffset ||
+ SliceSize != DL.getTypeStoreSize(NewAI.getAllocatedType()) ||
+ !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
// Strip all inbounds GEPs and pointer casts to try to dig out any root
// alloca that should be re-examined after rewriting this instruction.
Value *OtherPtr = IsDest ? II.getRawSource() : II.getRawDest();
- if (AllocaInst *AI
- = dyn_cast<AllocaInst>(OtherPtr->stripInBoundsOffsets())) {
+ if (AllocaInst *AI =
+ dyn_cast<AllocaInst>(OtherPtr->stripInBoundsOffsets())) {
assert(AI != &OldAI && AI != &NewAI &&
"Splittable transfers cannot reach the same alloca on both ends.");
Pass.Worklist.insert(AI);
}
- if (EmitMemCpy) {
- Type *OtherPtrTy = OtherPtr->getType();
+ Type *OtherPtrTy = OtherPtr->getType();
+ unsigned OtherAS = OtherPtrTy->getPointerAddressSpace();
+
+ // Compute the relative offset for the other pointer within the transfer.
+ unsigned IntPtrWidth = DL.getPointerSizeInBits(OtherAS);
+ APInt OtherOffset(IntPtrWidth, NewBeginOffset - BeginOffset);
+ unsigned OtherAlign = MinAlign(II.getAlignment() ? II.getAlignment() : 1,
+ OtherOffset.zextOrTrunc(64).getZExtValue());
+ if (EmitMemCpy) {
// Compute the other pointer, folding as much as possible to produce
// a single, simple GEP in most cases.
- OtherPtr = getAdjustedPtr(IRB, DL, OtherPtr, RelOffset, OtherPtrTy,
+ OtherPtr = getAdjustedPtr(IRB, DL, OtherPtr, OtherOffset, OtherPtrTy,
OtherPtr->getName() + ".");
- Value *OurPtr =
- getAdjustedAllocaPtr(IRB, NewBeginOffset, OldPtr->getType());
+ Value *OurPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
Type *SizeTy = II.getLength()->getType();
Constant *Size = ConstantInt::get(SizeTy, NewEndOffset - NewBeginOffset);
- CallInst *New = IRB.CreateMemCpy(IsDest ? OurPtr : OtherPtr,
- IsDest ? OtherPtr : OurPtr,
- Size, Align, II.isVolatile());
+ CallInst *New = IRB.CreateMemCpy(
+ IsDest ? OurPtr : OtherPtr, IsDest ? OtherPtr : OurPtr, Size,
+ MinAlign(SliceAlign, OtherAlign), II.isVolatile());
(void)New;
DEBUG(dbgs() << " to: " << *New << "\n");
return false;
}
- // Note that we clamp the alignment to 1 here as a 0 alignment for a memcpy
- // is equivalent to 1, but that isn't true if we end up rewriting this as
- // a load or store.
- if (!Align)
- Align = 1;
-
bool IsWholeAlloca = NewBeginOffset == NewAllocaBeginOffset &&
NewEndOffset == NewAllocaEndOffset;
uint64_t Size = NewEndOffset - NewBeginOffset;
unsigned BeginIndex = VecTy ? getIndex(NewBeginOffset) : 0;
unsigned EndIndex = VecTy ? getIndex(NewEndOffset) : 0;
unsigned NumElements = EndIndex - BeginIndex;
- IntegerType *SubIntTy
- = IntTy ? Type::getIntNTy(IntTy->getContext(), Size*8) : 0;
+ IntegerType *SubIntTy =
+ IntTy ? Type::getIntNTy(IntTy->getContext(), Size * 8) : nullptr;
- Type *OtherPtrTy = NewAI.getType();
+ // Reset the other pointer type to match the register type we're going to
+ // use, but using the address space of the original other pointer.
if (VecTy && !IsWholeAlloca) {
if (NumElements == 1)
OtherPtrTy = VecTy->getElementType();
else
OtherPtrTy = VectorType::get(VecTy->getElementType(), NumElements);
- OtherPtrTy = OtherPtrTy->getPointerTo();
+ OtherPtrTy = OtherPtrTy->getPointerTo(OtherAS);
} else if (IntTy && !IsWholeAlloca) {
- OtherPtrTy = SubIntTy->getPointerTo();
+ OtherPtrTy = SubIntTy->getPointerTo(OtherAS);
+ } else {
+ OtherPtrTy = NewAllocaTy->getPointerTo(OtherAS);
}
- Value *SrcPtr = getAdjustedPtr(IRB, DL, OtherPtr, RelOffset, OtherPtrTy,
+ Value *SrcPtr = getAdjustedPtr(IRB, DL, OtherPtr, OtherOffset, OtherPtrTy,
OtherPtr->getName() + ".");
+ unsigned SrcAlign = OtherAlign;
Value *DstPtr = &NewAI;
- if (!IsDest)
+ unsigned DstAlign = SliceAlign;
+ if (!IsDest) {
std::swap(SrcPtr, DstPtr);
+ std::swap(SrcAlign, DstAlign);
+ }
Value *Src;
if (VecTy && !IsWholeAlloca && !IsDest) {
- Src = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "load");
+ Src = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "load");
Src = extractVector(IRB, Src, BeginIndex, EndIndex, "vec");
} else if (IntTy && !IsWholeAlloca && !IsDest) {
- Src = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "load");
+ Src = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "load");
Src = convertValue(DL, IRB, Src, IntTy);
uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
Src = extractInteger(DL, IRB, Src, SubIntTy, Offset, "extract");
} else {
- Src = IRB.CreateAlignedLoad(SrcPtr, Align, II.isVolatile(),
- "copyload");
+ Src =
+ IRB.CreateAlignedLoad(SrcPtr, SrcAlign, II.isVolatile(), "copyload");
}
if (VecTy && !IsWholeAlloca && IsDest) {
- Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "oldload");
+ Value *Old =
+ IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "oldload");
Src = insertVector(IRB, Old, Src, BeginIndex, "vec");
} else if (IntTy && !IsWholeAlloca && IsDest) {
- Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
- "oldload");
+ Value *Old =
+ IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(), "oldload");
Old = convertValue(DL, IRB, Old, IntTy);
uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
Src = insertInteger(DL, IRB, Old, Src, Offset, "insert");
}
StoreInst *Store = cast<StoreInst>(
- IRB.CreateAlignedStore(Src, DstPtr, Align, II.isVolatile()));
+ IRB.CreateAlignedStore(Src, DstPtr, DstAlign, II.isVolatile()));
(void)Store;
DEBUG(dbgs() << " to: " << *Store << "\n");
return !II.isVolatile();
DEBUG(dbgs() << " original: " << II << "\n");
assert(II.getArgOperand(1) == OldPtr);
- // Compute the intersecting offset range.
- assert(BeginOffset < NewAllocaEndOffset);
- assert(EndOffset > NewAllocaBeginOffset);
- uint64_t NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
- uint64_t NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
-
// Record this instruction for deletion.
Pass.DeadInsts.insert(&II);
- ConstantInt *Size
- = ConstantInt::get(cast<IntegerType>(II.getArgOperand(0)->getType()),
+ ConstantInt *Size =
+ ConstantInt::get(cast<IntegerType>(II.getArgOperand(0)->getType()),
NewEndOffset - NewBeginOffset);
- Value *Ptr = getAdjustedAllocaPtr(IRB, NewBeginOffset, OldPtr->getType());
+ Value *Ptr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
Value *New;
if (II.getIntrinsicID() == Intrinsic::lifetime_start)
New = IRB.CreateLifetimeStart(Ptr, Size);
// the old pointer, which necessarily must be in the right position to
// dominate the PHI.
IRBuilderTy PtrBuilder(IRB);
- PtrBuilder.SetInsertPoint(OldPtr);
+ if (isa<PHINode>(OldPtr))
+ PtrBuilder.SetInsertPoint(OldPtr->getParent()->getFirstInsertionPt());
+ else
+ PtrBuilder.SetInsertPoint(OldPtr);
PtrBuilder.SetCurrentDebugLocation(OldPtr->getDebugLoc());
- Value *NewPtr =
- getAdjustedAllocaPtr(PtrBuilder, BeginOffset, OldPtr->getType());
+ Value *NewPtr = getNewAllocaSlicePtr(PtrBuilder, OldPtr->getType());
// Replace the operands which were using the old pointer.
std::replace(PN.op_begin(), PN.op_end(), cast<Value>(OldPtr), NewPtr);
assert(BeginOffset >= NewAllocaBeginOffset && "Selects are unsplittable");
assert(EndOffset <= NewAllocaEndOffset && "Selects are unsplittable");
- Value *NewPtr = getAdjustedAllocaPtr(IRB, BeginOffset, OldPtr->getType());
+ Value *NewPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
// Replace the operands which were using the old pointer.
if (SI.getOperand(1) == OldPtr)
SI.setOperand(1, NewPtr);
SelectUsers.insert(&SI);
return true;
}
-
};
}
/// Enqueue all the users of the given instruction for further processing.
/// This uses a set to de-duplicate users.
void enqueueUsers(Instruction &I) {
- for (Value::use_iterator UI = I.use_begin(), UE = I.use_end(); UI != UE;
- ++UI)
- if (Visited.insert(*UI))
- Queue.push_back(&UI.getUse());
+ for (Use &U : I.uses())
+ if (Visited.insert(U.getUser()).second)
+ Queue.push_back(&U);
}
// Conservative default is to not rewrite anything.
bool visitInstruction(Instruction &I) { return false; }
/// \brief Generic recursive split emission class.
- template <typename Derived>
- class OpSplitter {
+ template <typename Derived> class OpSplitter {
protected:
/// The builder used to form new instructions.
IRBuilderTy IRB;
/// Initialize the splitter with an insertion point, Ptr and start with a
/// single zero GEP index.
OpSplitter(Instruction *InsertionPoint, Value *Ptr)
- : IRB(InsertionPoint), GEPIndices(1, IRB.getInt32(0)), Ptr(Ptr) {}
+ : IRB(InsertionPoint), GEPIndices(1, IRB.getInt32(0)), Ptr(Ptr) {}
public:
/// \brief Generic recursive split emission routine.
struct LoadOpSplitter : public OpSplitter<LoadOpSplitter> {
LoadOpSplitter(Instruction *InsertionPoint, Value *Ptr)
- : OpSplitter<LoadOpSplitter>(InsertionPoint, Ptr) {}
+ : OpSplitter<LoadOpSplitter>(InsertionPoint, Ptr) {}
/// Emit a leaf load of a single value. This is called at the leaves of the
/// recursive emission to actually load values.
struct StoreOpSplitter : public OpSplitter<StoreOpSplitter> {
StoreOpSplitter(Instruction *InsertionPoint, Value *Ptr)
- : OpSplitter<StoreOpSplitter>(InsertionPoint, Ptr) {}
+ : OpSplitter<StoreOpSplitter>(InsertionPoint, Ptr) {}
/// Emit a leaf store of a single value. This is called at the leaves of the
/// recursive emission to actually produce stores.
assert(Ty->isSingleValueType());
// Extract the single value and store it using the indices.
Value *Store = IRB.CreateStore(
- IRB.CreateExtractValue(Agg, Indices, Name + ".extract"),
- IRB.CreateInBoundsGEP(Ptr, GEPIndices, Name + ".gep"));
+ IRB.CreateExtractValue(Agg, Indices, Name + ".extract"),
+ IRB.CreateInBoundsGEP(Ptr, GEPIndices, Name + ".gep"));
(void)Store;
DEBUG(dbgs() << " to: " << *Store << "\n");
}
/// when the size or offset cause either end of type-based partition to be off.
/// Also, this is a best-effort routine. It is reasonable to give up and not
/// return a type if necessary.
-static Type *getTypePartition(const DataLayout &DL, Type *Ty,
- uint64_t Offset, uint64_t Size) {
+static Type *getTypePartition(const DataLayout &DL, Type *Ty, uint64_t Offset,
+ uint64_t Size) {
if (Offset == 0 && DL.getTypeAllocSize(Ty) == Size)
return stripAggregateTypeWrapping(DL, Ty);
if (Offset > DL.getTypeAllocSize(Ty) ||
(DL.getTypeAllocSize(Ty) - Offset) < Size)
- return 0;
+ return nullptr;
if (SequentialType *SeqTy = dyn_cast<SequentialType>(Ty)) {
// We can't partition pointers...
if (SeqTy->isPointerTy())
- return 0;
+ return nullptr;
Type *ElementTy = SeqTy->getElementType();
uint64_t ElementSize = DL.getTypeAllocSize(ElementTy);
uint64_t NumSkippedElements = Offset / ElementSize;
if (ArrayType *ArrTy = dyn_cast<ArrayType>(SeqTy)) {
if (NumSkippedElements >= ArrTy->getNumElements())
- return 0;
+ return nullptr;
} else if (VectorType *VecTy = dyn_cast<VectorType>(SeqTy)) {
if (NumSkippedElements >= VecTy->getNumElements())
- return 0;
+ return nullptr;
}
Offset -= NumSkippedElements * ElementSize;
if (Offset > 0 || Size < ElementSize) {
// Bail if the partition ends in a different array element.
if ((Offset + Size) > ElementSize)
- return 0;
+ return nullptr;
// Recurse through the element type trying to peel off offset bytes.
return getTypePartition(DL, ElementTy, Offset, Size);
}
assert(Size > ElementSize);
uint64_t NumElements = Size / ElementSize;
if (NumElements * ElementSize != Size)
- return 0;
+ return nullptr;
return ArrayType::get(ElementTy, NumElements);
}
StructType *STy = dyn_cast<StructType>(Ty);
if (!STy)
- return 0;
+ return nullptr;
const StructLayout *SL = DL.getStructLayout(STy);
if (Offset >= SL->getSizeInBytes())
- return 0;
+ return nullptr;
uint64_t EndOffset = Offset + Size;
if (EndOffset > SL->getSizeInBytes())
- return 0;
+ return nullptr;
unsigned Index = SL->getElementContainingOffset(Offset);
Offset -= SL->getElementOffset(Index);
Type *ElementTy = STy->getElementType(Index);
uint64_t ElementSize = DL.getTypeAllocSize(ElementTy);
if (Offset >= ElementSize)
- return 0; // The offset points into alignment padding.
+ return nullptr; // 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;
+ return nullptr;
return getTypePartition(DL, ElementTy, Offset, Size);
}
assert(Offset == 0);
if (EndOffset < SL->getSizeInBytes()) {
unsigned EndIndex = SL->getElementContainingOffset(EndOffset);
if (Index == EndIndex)
- return 0; // Within a single element and its padding.
+ return nullptr; // Within a single element and its padding.
// Don't try to form "natural" types if the elements don't line up with the
// expected size.
// FIXME: We could potentially recurse down through the last element in the
// sub-struct to find a natural end point.
if (SL->getElementOffset(EndIndex) != EndOffset)
- return 0;
+ return nullptr;
assert(Index < EndIndex);
EE = STy->element_begin() + EndIndex;
}
// Try to build up a sub-structure.
- StructType *SubTy = StructType::get(STy->getContext(), makeArrayRef(EI, EE),
- STy->isPacked());
+ StructType *SubTy =
+ StructType::get(STy->getContext(), makeArrayRef(EI, EE), STy->isPacked());
const StructLayout *SubSL = DL.getStructLayout(SubTy);
if (Size != SubSL->getSizeInBytes())
- return 0; // The sub-struct doesn't have quite the size needed.
+ return nullptr; // The sub-struct doesn't have quite the size needed.
return SubTy;
}
+/// \brief Pre-split loads and stores to simplify rewriting.
+///
+/// We want to break up the splittable load+store pairs as much as
+/// possible. This is important to do as a preprocessing step, as once we
+/// start rewriting the accesses to partitions of the alloca we lose the
+/// necessary information to correctly split apart paired loads and stores
+/// which both point into this alloca. The case to consider is something like
+/// the following:
+///
+/// %a = alloca [12 x i8]
+/// %gep1 = getelementptr [12 x i8]* %a, i32 0, i32 0
+/// %gep2 = getelementptr [12 x i8]* %a, i32 0, i32 4
+/// %gep3 = getelementptr [12 x i8]* %a, i32 0, i32 8
+/// %iptr1 = bitcast i8* %gep1 to i64*
+/// %iptr2 = bitcast i8* %gep2 to i64*
+/// %fptr1 = bitcast i8* %gep1 to float*
+/// %fptr2 = bitcast i8* %gep2 to float*
+/// %fptr3 = bitcast i8* %gep3 to float*
+/// store float 0.0, float* %fptr1
+/// store float 1.0, float* %fptr2
+/// %v = load i64* %iptr1
+/// store i64 %v, i64* %iptr2
+/// %f1 = load float* %fptr2
+/// %f2 = load float* %fptr3
+///
+/// Here we want to form 3 partitions of the alloca, each 4 bytes large, and
+/// promote everything so we recover the 2 SSA values that should have been
+/// there all along.
+///
+/// \returns true if any changes are made.
+bool SROA::presplitLoadsAndStores(AllocaInst &AI, AllocaSlices &AS) {
+ DEBUG(dbgs() << "Pre-splitting loads and stores\n");
+
+ // Track the loads and stores which are candidates for pre-splitting here, in
+ // the order they first appear during the partition scan. These give stable
+ // iteration order and a basis for tracking which loads and stores we
+ // actually split.
+ SmallVector<LoadInst *, 4> Loads;
+ SmallVector<StoreInst *, 4> Stores;
+
+ // We need to accumulate the splits required of each load or store where we
+ // can find them via a direct lookup. This is important to cross-check loads
+ // and stores against each other. We also track the slice so that we can kill
+ // all the slices that end up split.
+ struct SplitOffsets {
+ Slice *S;
+ std::vector<uint64_t> Splits;
+ };
+ SmallDenseMap<Instruction *, SplitOffsets, 8> SplitOffsetsMap;
+
+ // Track loads out of this alloca which cannot, for any reason, be pre-split.
+ // This is important as we also cannot pre-split stores of those loads!
+ // FIXME: This is all pretty gross. It means that we can be more aggressive
+ // in pre-splitting when the load feeding the store happens to come from
+ // a separate alloca. Put another way, the effectiveness of SROA would be
+ // decreased by a frontend which just concatenated all of its local allocas
+ // into one big flat alloca. But defeating such patterns is exactly the job
+ // SROA is tasked with! Sadly, to not have this discrepancy we would have
+ // change store pre-splitting to actually force pre-splitting of the load
+ // that feeds it *and all stores*. That makes pre-splitting much harder, but
+ // maybe it would make it more principled?
+ SmallPtrSet<LoadInst *, 8> UnsplittableLoads;
+
+ DEBUG(dbgs() << " Searching for candidate loads and stores\n");
+ for (auto &P : AS.partitions()) {
+ for (Slice &S : P) {
+ Instruction *I = cast<Instruction>(S.getUse()->getUser());
+ if (!S.isSplittable() ||S.endOffset() <= P.endOffset()) {
+ // If this was a load we have to track that it can't participate in any
+ // pre-splitting!
+ if (auto *LI = dyn_cast<LoadInst>(I))
+ UnsplittableLoads.insert(LI);
+ continue;
+ }
+ assert(P.endOffset() > S.beginOffset() &&
+ "Empty or backwards partition!");
+
+ // Determine if this is a pre-splittable slice.
+ if (auto *LI = dyn_cast<LoadInst>(I)) {
+ assert(!LI->isVolatile() && "Cannot split volatile loads!");
+
+ // The load must be used exclusively to store into other pointers for
+ // us to be able to arbitrarily pre-split it. The stores must also be
+ // simple to avoid changing semantics.
+ auto IsLoadSimplyStored = [](LoadInst *LI) {
+ for (User *LU : LI->users()) {
+ auto *SI = dyn_cast<StoreInst>(LU);
+ if (!SI || !SI->isSimple())
+ return false;
+ }
+ return true;
+ };
+ if (!IsLoadSimplyStored(LI)) {
+ UnsplittableLoads.insert(LI);
+ continue;
+ }
+
+ Loads.push_back(LI);
+ } else if (auto *SI = dyn_cast<StoreInst>(S.getUse()->getUser())) {
+ if (!SI ||
+ S.getUse() != &SI->getOperandUse(SI->getPointerOperandIndex()))
+ continue;
+ auto *StoredLoad = dyn_cast<LoadInst>(SI->getValueOperand());
+ if (!StoredLoad || !StoredLoad->isSimple())
+ continue;
+ assert(!SI->isVolatile() && "Cannot split volatile stores!");
+
+ Stores.push_back(SI);
+ } else {
+ // Other uses cannot be pre-split.
+ continue;
+ }
+
+ // Record the initial split.
+ DEBUG(dbgs() << " Candidate: " << *I << "\n");
+ auto &Offsets = SplitOffsetsMap[I];
+ assert(Offsets.Splits.empty() &&
+ "Should not have splits the first time we see an instruction!");
+ Offsets.S = &S;
+ Offsets.Splits.push_back(P.endOffset() - S.beginOffset());
+ }
+
+ // Now scan the already split slices, and add a split for any of them which
+ // we're going to pre-split.
+ for (Slice *S : P.splitSliceTails()) {
+ auto SplitOffsetsMapI =
+ SplitOffsetsMap.find(cast<Instruction>(S->getUse()->getUser()));
+ if (SplitOffsetsMapI == SplitOffsetsMap.end())
+ continue;
+ auto &Offsets = SplitOffsetsMapI->second;
+
+ assert(Offsets.S == S && "Found a mismatched slice!");
+ assert(!Offsets.Splits.empty() &&
+ "Cannot have an empty set of splits on the second partition!");
+ assert(Offsets.Splits.back() ==
+ P.beginOffset() - Offsets.S->beginOffset() &&
+ "Previous split does not end where this one begins!");
+
+ // Record each split. The last partition's end isn't needed as the size
+ // of the slice dictates that.
+ if (S->endOffset() > P.endOffset())
+ Offsets.Splits.push_back(P.endOffset() - Offsets.S->beginOffset());
+ }
+ }
+
+ // We may have split loads where some of their stores are split stores. For
+ // such loads and stores, we can only pre-split them if their splits exactly
+ // match relative to their starting offset. We have to verify this prior to
+ // any rewriting.
+ Stores.erase(
+ std::remove_if(Stores.begin(), Stores.end(),
+ [&UnsplittableLoads, &SplitOffsetsMap](StoreInst *SI) {
+ // Lookup the load we are storing in our map of split
+ // offsets.
+ auto *LI = cast<LoadInst>(SI->getValueOperand());
+ // If it was completely unsplittable, then we're done,
+ // and this store can't be pre-split.
+ if (UnsplittableLoads.count(LI))
+ return true;
+
+ auto LoadOffsetsI = SplitOffsetsMap.find(LI);
+ if (LoadOffsetsI == SplitOffsetsMap.end())
+ return false; // Unrelated loads are definitely safe.
+ auto &LoadOffsets = LoadOffsetsI->second;
+
+ // Now lookup the store's offsets.
+ auto &StoreOffsets = SplitOffsetsMap[SI];
+
+ // If the relative offsets of each split in the load and
+ // store match exactly, then we can split them and we
+ // don't need to remove them here.
+ if (LoadOffsets.Splits == StoreOffsets.Splits)
+ return false;
+
+ DEBUG(dbgs()
+ << " Mismatched splits for load and store:\n"
+ << " " << *LI << "\n"
+ << " " << *SI << "\n");
+
+ // We've found a store and load that we need to split
+ // with mismatched relative splits. Just give up on them
+ // and remove both instructions from our list of
+ // candidates.
+ UnsplittableLoads.insert(LI);
+ return true;
+ }),
+ Stores.end());
+ // Now we have to go *back* through all te stores, because a later store may
+ // have caused an earlier store's load to become unsplittable and if it is
+ // unsplittable for the later store, then we can't rely on it being split in
+ // the earlier store either.
+ Stores.erase(std::remove_if(Stores.begin(), Stores.end(),
+ [&UnsplittableLoads](StoreInst *SI) {
+ auto *LI =
+ cast<LoadInst>(SI->getValueOperand());
+ return UnsplittableLoads.count(LI);
+ }),
+ Stores.end());
+ // Once we've established all the loads that can't be split for some reason,
+ // filter any that made it into our list out.
+ Loads.erase(std::remove_if(Loads.begin(), Loads.end(),
+ [&UnsplittableLoads](LoadInst *LI) {
+ return UnsplittableLoads.count(LI);
+ }),
+ Loads.end());
+
+
+ // If no loads or stores are left, there is no pre-splitting to be done for
+ // this alloca.
+ if (Loads.empty() && Stores.empty())
+ return false;
+
+ // From here on, we can't fail and will be building new accesses, so rig up
+ // an IR builder.
+ IRBuilderTy IRB(&AI);
+
+ // Collect the new slices which we will merge into the alloca slices.
+ SmallVector<Slice, 4> NewSlices;
+
+ // Track any allocas we end up splitting loads and stores for so we iterate
+ // on them.
+ SmallPtrSet<AllocaInst *, 4> ResplitPromotableAllocas;
+
+ // At this point, we have collected all of the loads and stores we can
+ // pre-split, and the specific splits needed for them. We actually do the
+ // splitting in a specific order in order to handle when one of the loads in
+ // the value operand to one of the stores.
+ //
+ // First, we rewrite all of the split loads, and just accumulate each split
+ // load in a parallel structure. We also build the slices for them and append
+ // them to the alloca slices.
+ SmallDenseMap<LoadInst *, std::vector<LoadInst *>, 1> SplitLoadsMap;
+ std::vector<LoadInst *> SplitLoads;
+ for (LoadInst *LI : Loads) {
+ SplitLoads.clear();
+
+ IntegerType *Ty = cast<IntegerType>(LI->getType());
+ uint64_t LoadSize = Ty->getBitWidth() / 8;
+ assert(LoadSize > 0 && "Cannot have a zero-sized integer load!");
+
+ auto &Offsets = SplitOffsetsMap[LI];
+ assert(LoadSize == Offsets.S->endOffset() - Offsets.S->beginOffset() &&
+ "Slice size should always match load size exactly!");
+ uint64_t BaseOffset = Offsets.S->beginOffset();
+ assert(BaseOffset + LoadSize > BaseOffset &&
+ "Cannot represent alloca access size using 64-bit integers!");
+
+ Instruction *BasePtr = cast<Instruction>(LI->getPointerOperand());
+ IRB.SetInsertPoint(BasicBlock::iterator(LI));
+
+ DEBUG(dbgs() << " Splitting load: " << *LI << "\n");
+
+ uint64_t PartOffset = 0, PartSize = Offsets.Splits.front();
+ int Idx = 0, Size = Offsets.Splits.size();
+ for (;;) {
+ auto *PartTy = Type::getIntNTy(Ty->getContext(), PartSize * 8);
+ auto *PartPtrTy = PartTy->getPointerTo(LI->getPointerAddressSpace());
+ LoadInst *PLoad = IRB.CreateAlignedLoad(
+ getAdjustedPtr(IRB, *DL, BasePtr,
+ APInt(DL->getPointerSizeInBits(), PartOffset),
+ PartPtrTy, BasePtr->getName() + "."),
+ getAdjustedAlignment(LI, PartOffset, *DL), /*IsVolatile*/ false,
+ LI->getName());
+
+ // Append this load onto the list of split loads so we can find it later
+ // to rewrite the stores.
+ SplitLoads.push_back(PLoad);
+
+ // Now build a new slice for the alloca.
+ NewSlices.push_back(
+ Slice(BaseOffset + PartOffset, BaseOffset + PartOffset + PartSize,
+ &PLoad->getOperandUse(PLoad->getPointerOperandIndex()),
+ /*IsSplittable*/ false));
+ DEBUG(dbgs() << " new slice [" << NewSlices.back().beginOffset()
+ << ", " << NewSlices.back().endOffset() << "): " << *PLoad
+ << "\n");
+
+ // See if we've handled all the splits.
+ if (Idx >= Size)
+ break;
+
+ // Setup the next partition.
+ PartOffset = Offsets.Splits[Idx];
+ ++Idx;
+ PartSize = (Idx < Size ? Offsets.Splits[Idx] : LoadSize) - PartOffset;
+ }
+
+ // Now that we have the split loads, do the slow walk over all uses of the
+ // load and rewrite them as split stores, or save the split loads to use
+ // below if the store is going to be split there anyways.
+ bool DeferredStores = false;
+ for (User *LU : LI->users()) {
+ StoreInst *SI = cast<StoreInst>(LU);
+ if (!Stores.empty() && SplitOffsetsMap.count(SI)) {
+ DeferredStores = true;
+ DEBUG(dbgs() << " Deferred splitting of store: " << *SI << "\n");
+ continue;
+ }
+
+ Value *StoreBasePtr = SI->getPointerOperand();
+ IRB.SetInsertPoint(BasicBlock::iterator(SI));
+
+ DEBUG(dbgs() << " Splitting store of load: " << *SI << "\n");
+
+ for (int Idx = 0, Size = SplitLoads.size(); Idx < Size; ++Idx) {
+ LoadInst *PLoad = SplitLoads[Idx];
+ uint64_t PartOffset = Idx == 0 ? 0 : Offsets.Splits[Idx - 1];
+ auto *PartPtrTy =
+ PLoad->getType()->getPointerTo(SI->getPointerAddressSpace());
+
+ StoreInst *PStore = IRB.CreateAlignedStore(
+ PLoad, getAdjustedPtr(IRB, *DL, StoreBasePtr,
+ APInt(DL->getPointerSizeInBits(), PartOffset),
+ PartPtrTy, StoreBasePtr->getName() + "."),
+ getAdjustedAlignment(SI, PartOffset, *DL), /*IsVolatile*/ false);
+ (void)PStore;
+ DEBUG(dbgs() << " +" << PartOffset << ":" << *PStore << "\n");
+ }
+
+ // We want to immediately iterate on any allocas impacted by splitting
+ // this store, and we have to track any promotable alloca (indicated by
+ // a direct store) as needing to be resplit because it is no longer
+ // promotable.
+ if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(StoreBasePtr)) {
+ ResplitPromotableAllocas.insert(OtherAI);
+ Worklist.insert(OtherAI);
+ } else if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(
+ StoreBasePtr->stripInBoundsOffsets())) {
+ Worklist.insert(OtherAI);
+ }
+
+ // Mark the original store as dead.
+ DeadInsts.insert(SI);
+ }
+
+ // Save the split loads if there are deferred stores among the users.
+ if (DeferredStores)
+ SplitLoadsMap.insert(std::make_pair(LI, std::move(SplitLoads)));
+
+ // Mark the original load as dead and kill the original slice.
+ DeadInsts.insert(LI);
+ Offsets.S->kill();
+ }
+
+ // Second, we rewrite all of the split stores. At this point, we know that
+ // all loads from this alloca have been split already. For stores of such
+ // loads, we can simply look up the pre-existing split loads. For stores of
+ // other loads, we split those loads first and then write split stores of
+ // them.
+ for (StoreInst *SI : Stores) {
+ auto *LI = cast<LoadInst>(SI->getValueOperand());
+ IntegerType *Ty = cast<IntegerType>(LI->getType());
+ uint64_t StoreSize = Ty->getBitWidth() / 8;
+ assert(StoreSize > 0 && "Cannot have a zero-sized integer store!");
+
+ auto &Offsets = SplitOffsetsMap[SI];
+ assert(StoreSize == Offsets.S->endOffset() - Offsets.S->beginOffset() &&
+ "Slice size should always match load size exactly!");
+ uint64_t BaseOffset = Offsets.S->beginOffset();
+ assert(BaseOffset + StoreSize > BaseOffset &&
+ "Cannot represent alloca access size using 64-bit integers!");
+
+ Value *LoadBasePtr = LI->getPointerOperand();
+ Instruction *StoreBasePtr = cast<Instruction>(SI->getPointerOperand());
+
+ DEBUG(dbgs() << " Splitting store: " << *SI << "\n");
+
+ // Check whether we have an already split load.
+ auto SplitLoadsMapI = SplitLoadsMap.find(LI);
+ std::vector<LoadInst *> *SplitLoads = nullptr;
+ if (SplitLoadsMapI != SplitLoadsMap.end()) {
+ SplitLoads = &SplitLoadsMapI->second;
+ assert(SplitLoads->size() == Offsets.Splits.size() + 1 &&
+ "Too few split loads for the number of splits in the store!");
+ } else {
+ DEBUG(dbgs() << " of load: " << *LI << "\n");
+ }
+
+ uint64_t PartOffset = 0, PartSize = Offsets.Splits.front();
+ int Idx = 0, Size = Offsets.Splits.size();
+ for (;;) {
+ auto *PartTy = Type::getIntNTy(Ty->getContext(), PartSize * 8);
+ auto *PartPtrTy = PartTy->getPointerTo(SI->getPointerAddressSpace());
+
+ // Either lookup a split load or create one.
+ LoadInst *PLoad;
+ if (SplitLoads) {
+ PLoad = (*SplitLoads)[Idx];
+ } else {
+ IRB.SetInsertPoint(BasicBlock::iterator(LI));
+ PLoad = IRB.CreateAlignedLoad(
+ getAdjustedPtr(IRB, *DL, LoadBasePtr,
+ APInt(DL->getPointerSizeInBits(), PartOffset),
+ PartPtrTy, LoadBasePtr->getName() + "."),
+ getAdjustedAlignment(LI, PartOffset, *DL), /*IsVolatile*/ false,
+ LI->getName());
+ }
+
+ // And store this partition.
+ IRB.SetInsertPoint(BasicBlock::iterator(SI));
+ StoreInst *PStore = IRB.CreateAlignedStore(
+ PLoad, getAdjustedPtr(IRB, *DL, StoreBasePtr,
+ APInt(DL->getPointerSizeInBits(), PartOffset),
+ PartPtrTy, StoreBasePtr->getName() + "."),
+ getAdjustedAlignment(SI, PartOffset, *DL), /*IsVolatile*/ false);
+
+ // Now build a new slice for the alloca.
+ NewSlices.push_back(
+ Slice(BaseOffset + PartOffset, BaseOffset + PartOffset + PartSize,
+ &PStore->getOperandUse(PStore->getPointerOperandIndex()),
+ /*IsSplittable*/ false));
+ DEBUG(dbgs() << " new slice [" << NewSlices.back().beginOffset()
+ << ", " << NewSlices.back().endOffset() << "): " << *PStore
+ << "\n");
+ if (!SplitLoads) {
+ DEBUG(dbgs() << " of split load: " << *PLoad << "\n");
+ }
+
+ // See if we've finished all the splits.
+ if (Idx >= Size)
+ break;
+
+ // Setup the next partition.
+ PartOffset = Offsets.Splits[Idx];
+ ++Idx;
+ PartSize = (Idx < Size ? Offsets.Splits[Idx] : StoreSize) - PartOffset;
+ }
+
+ // We want to immediately iterate on any allocas impacted by splitting
+ // this load, which is only relevant if it isn't a load of this alloca and
+ // thus we didn't already split the loads above. We also have to keep track
+ // of any promotable allocas we split loads on as they can no longer be
+ // promoted.
+ if (!SplitLoads) {
+ if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(LoadBasePtr)) {
+ assert(OtherAI != &AI && "We can't re-split our own alloca!");
+ ResplitPromotableAllocas.insert(OtherAI);
+ Worklist.insert(OtherAI);
+ } else if (AllocaInst *OtherAI = dyn_cast<AllocaInst>(
+ LoadBasePtr->stripInBoundsOffsets())) {
+ assert(OtherAI != &AI && "We can't re-split our own alloca!");
+ Worklist.insert(OtherAI);
+ }
+ }
+
+ // Mark the original store as dead now that we've split it up and kill its
+ // slice. Note that we leave the original load in place unless this store
+ // was its ownly use. It may in turn be split up if it is an alloca load
+ // for some other alloca, but it may be a normal load. This may introduce
+ // redundant loads, but where those can be merged the rest of the optimizer
+ // should handle the merging, and this uncovers SSA splits which is more
+ // important. In practice, the original loads will almost always be fully
+ // split and removed eventually, and the splits will be merged by any
+ // trivial CSE, including instcombine.
+ if (LI->hasOneUse()) {
+ assert(*LI->user_begin() == SI && "Single use isn't this store!");
+ DeadInsts.insert(LI);
+ }
+ DeadInsts.insert(SI);
+ Offsets.S->kill();
+ }
+
+ // Remove the killed slices that have ben pre-split.
+ AS.erase(std::remove_if(AS.begin(), AS.end(), [](const Slice &S) {
+ return S.isDead();
+ }), AS.end());
+
+ // Insert our new slices. This will sort and merge them into the sorted
+ // sequence.
+ AS.insert(NewSlices);
+
+ DEBUG(dbgs() << " Pre-split slices:\n");
+#ifndef NDEBUG
+ for (auto I = AS.begin(), E = AS.end(); I != E; ++I)
+ DEBUG(AS.print(dbgs(), I, " "));
+#endif
+
+ // Finally, don't try to promote any allocas that new require re-splitting.
+ // They have already been added to the worklist above.
+ PromotableAllocas.erase(
+ std::remove_if(
+ PromotableAllocas.begin(), PromotableAllocas.end(),
+ [&](AllocaInst *AI) { return ResplitPromotableAllocas.count(AI); }),
+ PromotableAllocas.end());
+
+ return true;
+}
+
/// \brief Rewrite an alloca partition's users.
///
/// This routine drives both of the rewriting goals of the SROA pass. It tries
/// 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::rewritePartition(AllocaInst &AI, AllocaSlices &S,
- AllocaSlices::iterator B, AllocaSlices::iterator E,
- int64_t BeginOffset, int64_t EndOffset,
- ArrayRef<AllocaSlices::iterator> SplitUses) {
- assert(BeginOffset < EndOffset);
- uint64_t SliceSize = EndOffset - BeginOffset;
-
+AllocaInst *SROA::rewritePartition(AllocaInst &AI, AllocaSlices &AS,
+ AllocaSlices::Partition &P) {
// 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 *SliceTy = 0;
- if (Type *CommonUseTy = findCommonType(B, E, EndOffset))
- if (DL->getTypeAllocSize(CommonUseTy) >= SliceSize)
+ Type *SliceTy = nullptr;
+ if (Type *CommonUseTy = findCommonType(P.begin(), P.end(), P.endOffset()))
+ if (DL->getTypeAllocSize(CommonUseTy) >= P.size())
SliceTy = CommonUseTy;
if (!SliceTy)
if (Type *TypePartitionTy = getTypePartition(*DL, AI.getAllocatedType(),
- BeginOffset, SliceSize))
+ P.beginOffset(), P.size()))
SliceTy = TypePartitionTy;
if ((!SliceTy || (SliceTy->isArrayTy() &&
SliceTy->getArrayElementType()->isIntegerTy())) &&
- DL->isLegalInteger(SliceSize * 8))
- SliceTy = Type::getIntNTy(*C, SliceSize * 8);
+ DL->isLegalInteger(P.size() * 8))
+ SliceTy = Type::getIntNTy(*C, P.size() * 8);
if (!SliceTy)
- SliceTy = ArrayType::get(Type::getInt8Ty(*C), SliceSize);
- assert(DL->getTypeAllocSize(SliceTy) >= SliceSize);
+ SliceTy = ArrayType::get(Type::getInt8Ty(*C), P.size());
+ assert(DL->getTypeAllocSize(SliceTy) >= P.size());
- bool IsVectorPromotable = isVectorPromotionViable(
- *DL, SliceTy, S, BeginOffset, EndOffset, B, E, SplitUses);
+ bool IsIntegerPromotable = isIntegerWideningViable(P, SliceTy, *DL);
- bool IsIntegerPromotable =
- !IsVectorPromotable &&
- isIntegerWideningViable(*DL, SliceTy, BeginOffset, S, B, E, SplitUses);
+ VectorType *VecTy =
+ IsIntegerPromotable ? nullptr : isVectorPromotionViable(P, *DL);
+ if (VecTy)
+ SliceTy = VecTy;
// 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
// perform phi and select speculation.
AllocaInst *NewAI;
if (SliceTy == AI.getAllocatedType()) {
- assert(BeginOffset == 0 &&
+ assert(P.beginOffset() == 0 &&
"Non-zero begin offset but same alloca type");
NewAI = &AI;
// FIXME: We should be able to bail at this point with "nothing changed".
// FIXME: We might want to defer PHI speculation until after here.
+ // FIXME: return nullptr;
} else {
unsigned Alignment = AI.getAlignment();
if (!Alignment) {
// type.
Alignment = DL->getABITypeAlignment(AI.getAllocatedType());
}
- Alignment = MinAlign(Alignment, BeginOffset);
+ Alignment = MinAlign(Alignment, P.beginOffset());
// If we will get at least this much alignment from the type alone, leave
// the alloca's alignment unconstrained.
if (Alignment <= DL->getABITypeAlignment(SliceTy))
Alignment = 0;
- NewAI = new AllocaInst(SliceTy, 0, Alignment,
- AI.getName() + ".sroa." + Twine(B - S.begin()), &AI);
+ NewAI = new AllocaInst(
+ SliceTy, nullptr, Alignment,
+ AI.getName() + ".sroa." + Twine(P.begin() - AS.begin()), &AI);
++NumNewAllocas;
}
DEBUG(dbgs() << "Rewriting alloca partition "
- << "[" << BeginOffset << "," << EndOffset << ") to: " << *NewAI
- << "\n");
+ << "[" << P.beginOffset() << "," << P.endOffset()
+ << ") to: " << *NewAI << "\n");
// Track the high watermark on the worklist as it is only relevant for
// promoted allocas. We will reset it to this point if the alloca is not in
SmallPtrSet<PHINode *, 8> PHIUsers;
SmallPtrSet<SelectInst *, 8> SelectUsers;
- AllocaSliceRewriter Rewriter(*DL, S, *this, AI, *NewAI, BeginOffset,
- EndOffset, IsVectorPromotable,
- IsIntegerPromotable, PHIUsers, SelectUsers);
+ AllocaSliceRewriter Rewriter(*DL, AS, *this, AI, *NewAI, P.beginOffset(),
+ P.endOffset(), IsIntegerPromotable, VecTy,
+ PHIUsers, SelectUsers);
bool Promotable = true;
- for (ArrayRef<AllocaSlices::iterator>::const_iterator SUI = SplitUses.begin(),
- SUE = SplitUses.end();
- SUI != SUE; ++SUI) {
- DEBUG(dbgs() << " rewriting split ");
- DEBUG(S.printSlice(dbgs(), *SUI, ""));
- Promotable &= Rewriter.visit(*SUI);
+ for (Slice *S : P.splitSliceTails()) {
+ Promotable &= Rewriter.visit(S);
++NumUses;
}
- for (AllocaSlices::iterator I = B; I != E; ++I) {
- DEBUG(dbgs() << " rewriting ");
- DEBUG(S.printSlice(dbgs(), I, ""));
- Promotable &= Rewriter.visit(I);
+ for (Slice &S : P) {
+ Promotable &= Rewriter.visit(&S);
++NumUses;
}
// If we have either PHIs or Selects to speculate, add them to those
// worklists and re-queue the new alloca so that we promote in on the
// next iteration.
- for (SmallPtrSetImpl<PHINode *>::iterator I = PHIUsers.begin(),
- E = PHIUsers.end();
- I != E; ++I)
- SpeculatablePHIs.insert(*I);
- for (SmallPtrSetImpl<SelectInst *>::iterator I = SelectUsers.begin(),
- E = SelectUsers.end();
- I != E; ++I)
- SpeculatableSelects.insert(*I);
+ for (PHINode *PHIUser : PHIUsers)
+ SpeculatablePHIs.insert(PHIUser);
+ for (SelectInst *SelectUser : SelectUsers)
+ SpeculatableSelects.insert(SelectUser);
Worklist.insert(NewAI);
}
} else {
PostPromotionWorklist.pop_back();
}
- return true;
-}
-
-namespace {
-struct IsSliceEndLessOrEqualTo {
- uint64_t UpperBound;
-
- IsSliceEndLessOrEqualTo(uint64_t UpperBound) : UpperBound(UpperBound) {}
-
- bool operator()(const AllocaSlices::iterator &I) {
- return I->endOffset() <= UpperBound;
- }
-};
-}
-
-static void
-removeFinishedSplitUses(SmallVectorImpl<AllocaSlices::iterator> &SplitUses,
- uint64_t &MaxSplitUseEndOffset, uint64_t Offset) {
- if (Offset >= MaxSplitUseEndOffset) {
- SplitUses.clear();
- MaxSplitUseEndOffset = 0;
- return;
- }
-
- size_t SplitUsesOldSize = SplitUses.size();
- SplitUses.erase(std::remove_if(SplitUses.begin(), SplitUses.end(),
- IsSliceEndLessOrEqualTo(Offset)),
- SplitUses.end());
- if (SplitUsesOldSize == SplitUses.size())
- return;
-
- // Recompute the max. While this is linear, so is remove_if.
- MaxSplitUseEndOffset = 0;
- for (SmallVectorImpl<AllocaSlices::iterator>::iterator
- SUI = SplitUses.begin(),
- SUE = SplitUses.end();
- SUI != SUE; ++SUI)
- MaxSplitUseEndOffset = std::max((*SUI)->endOffset(), MaxSplitUseEndOffset);
+ return NewAI;
}
/// \brief Walks the slices of an alloca and form partitions based on them,
/// rewriting each of their uses.
-bool SROA::splitAlloca(AllocaInst &AI, AllocaSlices &S) {
- if (S.begin() == S.end())
+bool SROA::splitAlloca(AllocaInst &AI, AllocaSlices &AS) {
+ if (AS.begin() == AS.end())
return false;
unsigned NumPartitions = 0;
bool Changed = false;
- SmallVector<AllocaSlices::iterator, 4> SplitUses;
- uint64_t MaxSplitUseEndOffset = 0;
-
- uint64_t BeginOffset = S.begin()->beginOffset();
-
- for (AllocaSlices::iterator SI = S.begin(), SJ = llvm::next(SI), SE = S.end();
- SI != SE; SI = SJ) {
- uint64_t MaxEndOffset = SI->endOffset();
-
- if (!SI->isSplittable()) {
- // When we're forming an unsplittable region, it must always start at the
- // first slice and will extend through its end.
- assert(BeginOffset == SI->beginOffset());
-
- // Form a partition including all of the overlapping slices with this
- // unsplittable slice.
- while (SJ != SE && SJ->beginOffset() < MaxEndOffset) {
- if (!SJ->isSplittable())
- MaxEndOffset = std::max(MaxEndOffset, SJ->endOffset());
- ++SJ;
- }
- } else {
- assert(SI->isSplittable()); // Established above.
-
- // Collect all of the overlapping splittable slices.
- while (SJ != SE && SJ->beginOffset() < MaxEndOffset &&
- SJ->isSplittable()) {
- MaxEndOffset = std::max(MaxEndOffset, SJ->endOffset());
- ++SJ;
- }
-
- // Back up MaxEndOffset and SJ if we ended the span early when
- // encountering an unsplittable slice.
- if (SJ != SE && SJ->beginOffset() < MaxEndOffset) {
- assert(!SJ->isSplittable());
- MaxEndOffset = SJ->beginOffset();
- }
- }
-
- // Check if we have managed to move the end offset forward yet. If so,
- // we'll have to rewrite uses and erase old split uses.
- if (BeginOffset < MaxEndOffset) {
- // Rewrite a sequence of overlapping slices.
- Changed |=
- rewritePartition(AI, S, SI, SJ, BeginOffset, MaxEndOffset, SplitUses);
- ++NumPartitions;
- removeFinishedSplitUses(SplitUses, MaxSplitUseEndOffset, MaxEndOffset);
- }
-
- // Accumulate all the splittable slices from the [SI,SJ) region which
- // overlap going forward.
- for (AllocaSlices::iterator SK = SI; SK != SJ; ++SK)
- if (SK->isSplittable() && SK->endOffset() > MaxEndOffset) {
- SplitUses.push_back(SK);
- MaxSplitUseEndOffset = std::max(SK->endOffset(), MaxSplitUseEndOffset);
- }
+ // First try to pre-split loads and stores.
+ Changed |= presplitLoadsAndStores(AI, AS);
- // If we're already at the end and we have no split uses, we're done.
- if (SJ == SE && SplitUses.empty())
- break;
-
- // If we have no split uses or no gap in offsets, we're ready to move to
- // the next slice.
- if (SplitUses.empty() || (SJ != SE && MaxEndOffset == SJ->beginOffset())) {
- BeginOffset = SJ->beginOffset();
+ // Now that we have identified any pre-splitting opportunities, mark any
+ // splittable (non-whole-alloca) loads and stores as unsplittable. If we fail
+ // to split these during pre-splitting, we want to force them to be
+ // rewritten into a partition.
+ bool IsSorted = true;
+ for (Slice &S : AS) {
+ if (!S.isSplittable())
continue;
- }
-
- // Even if we have split slices, if the next slice is splittable and the
- // split slices reach it, we can simply set up the beginning offset of the
- // next iteration to bridge between them.
- if (SJ != SE && SJ->isSplittable() &&
- MaxSplitUseEndOffset > SJ->beginOffset()) {
- BeginOffset = MaxEndOffset;
+ // FIXME: We currently leave whole-alloca splittable loads and stores. This
+ // used to be the only splittable loads and stores and we need to be
+ // confident that the above handling of splittable loads and stores is
+ // completely sufficient before we forcibly disable the remaining handling.
+ if (S.beginOffset() == 0 &&
+ S.endOffset() >= DL->getTypeAllocSize(AI.getAllocatedType()))
continue;
+ if (isa<LoadInst>(S.getUse()->getUser()) ||
+ isa<StoreInst>(S.getUse()->getUser())) {
+ S.makeUnsplittable();
+ IsSorted = false;
+ }
+ }
+ if (!IsSorted)
+ std::sort(AS.begin(), AS.end());
+
+ /// \brief Describes the allocas introduced by rewritePartition
+ /// in order to migrate the debug info.
+ struct Piece {
+ AllocaInst *Alloca;
+ uint64_t Offset;
+ uint64_t Size;
+ Piece(AllocaInst *AI, uint64_t O, uint64_t S)
+ : Alloca(AI), Offset(O), Size(S) {}
+ };
+ SmallVector<Piece, 4> Pieces;
+
+ // Rewrite each partition.
+ for (auto &P : AS.partitions()) {
+ if (AllocaInst *NewAI = rewritePartition(AI, AS, P)) {
+ Changed = true;
+ if (NewAI != &AI)
+ Pieces.push_back(Piece(NewAI, P.beginOffset(), P.size()));
}
-
- // Otherwise, we have a tail of split slices. Rewrite them with an empty
- // range of slices.
- uint64_t PostSplitEndOffset =
- SJ == SE ? MaxSplitUseEndOffset : SJ->beginOffset();
-
- Changed |= rewritePartition(AI, S, SJ, SJ, MaxEndOffset, PostSplitEndOffset,
- SplitUses);
++NumPartitions;
-
- if (SJ == SE)
- break; // Skip the rest, we don't need to do any cleanup.
-
- removeFinishedSplitUses(SplitUses, MaxSplitUseEndOffset,
- PostSplitEndOffset);
-
- // Now just reset the begin offset for the next iteration.
- BeginOffset = SJ->beginOffset();
}
NumAllocaPartitions += NumPartitions;
MaxPartitionsPerAlloca =
std::max<unsigned>(NumPartitions, MaxPartitionsPerAlloca);
+ // Migrate debug information from the old alloca to the new alloca(s)
+ // and the individial partitions.
+ if (DbgDeclareInst *DbgDecl = DbgDeclares.lookup(&AI)) {
+ DIVariable Var(DbgDecl->getVariable());
+ DIExpression Expr(DbgDecl->getExpression());
+ DIBuilder DIB(*AI.getParent()->getParent()->getParent(),
+ /*AllowUnresolved*/ false);
+ bool IsSplit = Pieces.size() > 1;
+ for (auto Piece : Pieces) {
+ // Create a piece expression describing the new partition or reuse AI's
+ // expression if there is only one partition.
+ if (IsSplit)
+ Expr = DIB.createPieceExpression(Piece.Offset, Piece.Size);
+ Instruction *NewDDI = DIB.insertDeclare(Piece.Alloca, Var, Expr, &AI);
+ NewDDI->setDebugLoc(DbgDecl->getDebugLoc());
+ assert((!DbgDeclares.count(Piece.Alloca) ||
+ DbgDeclares[Piece.Alloca] == cast<DbgDeclareInst>(NewDDI)
+ ) && "alloca already described");
+ DbgDeclares.insert(std::make_pair(Piece.Alloca,
+ cast<DbgDeclareInst>(NewDDI)));
+ }
+ }
return Changed;
}
Changed |= AggRewriter.rewrite(AI);
// Build the slices using a recursive instruction-visiting builder.
- AllocaSlices S(*DL, AI);
- DEBUG(S.print(dbgs()));
- if (S.isEscaped())
+ AllocaSlices AS(*DL, AI);
+ DEBUG(AS.print(dbgs()));
+ if (AS.isEscaped())
return Changed;
// Delete all the dead users of this alloca before splitting and rewriting it.
- for (AllocaSlices::dead_user_iterator DI = S.dead_user_begin(),
- DE = S.dead_user_end();
- DI != DE; ++DI) {
+ for (Instruction *DeadUser : AS.getDeadUsers()) {
// Free up everything used by this instruction.
- for (User::op_iterator DOI = (*DI)->op_begin(), DOE = (*DI)->op_end();
- DOI != DOE; ++DOI)
- clobberUse(*DOI);
+ for (Use &DeadOp : DeadUser->operands())
+ clobberUse(DeadOp);
// Now replace the uses of this instruction.
- (*DI)->replaceAllUsesWith(UndefValue::get((*DI)->getType()));
+ DeadUser->replaceAllUsesWith(UndefValue::get(DeadUser->getType()));
// And mark it for deletion.
- DeadInsts.insert(*DI);
+ DeadInsts.insert(DeadUser);
Changed = true;
}
- for (AllocaSlices::dead_op_iterator DO = S.dead_op_begin(),
- DE = S.dead_op_end();
- DO != DE; ++DO) {
- clobberUse(**DO);
+ for (Use *DeadOp : AS.getDeadOperands()) {
+ clobberUse(*DeadOp);
Changed = true;
}
// No slices to split. Leave the dead alloca for a later pass to clean up.
- if (S.begin() == S.end())
+ if (AS.begin() == AS.end())
return Changed;
- Changed |= splitAlloca(AI, S);
+ Changed |= splitAlloca(AI, AS);
DEBUG(dbgs() << " Speculating PHIs\n");
while (!SpeculatablePHIs.empty())
///
/// We also record the alloca instructions deleted here so that they aren't
/// subsequently handed to mem2reg to promote.
-void SROA::deleteDeadInstructions(SmallPtrSet<AllocaInst*, 4> &DeletedAllocas) {
+void SROA::deleteDeadInstructions(
+ SmallPtrSetImpl<AllocaInst *> &DeletedAllocas) {
while (!DeadInsts.empty()) {
Instruction *I = DeadInsts.pop_back_val();
DEBUG(dbgs() << "Deleting dead instruction: " << *I << "\n");
I->replaceAllUsesWith(UndefValue::get(I->getType()));
- for (User::op_iterator OI = I->op_begin(), E = I->op_end(); OI != E; ++OI)
- if (Instruction *U = dyn_cast<Instruction>(*OI)) {
+ for (Use &Operand : I->operands())
+ if (Instruction *U = dyn_cast<Instruction>(Operand)) {
// Zero out the operand and see if it becomes trivially dead.
- *OI = 0;
+ Operand = nullptr;
if (isInstructionTriviallyDead(U))
DeadInsts.insert(U);
}
- if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
DeletedAllocas.insert(AI);
+ if (DbgDeclareInst *DbgDecl = DbgDeclares.lookup(AI)) {
+ DbgDecl->eraseFromParent();
+ DbgDeclares.erase(AI);
+ }
+ }
++NumDeleted;
I->eraseFromParent();
@@ -3555,11 +4315,10 @@ void SROA::deleteDeadInstructions(SmallPtrSet<AllocaInst*, 4> &DeletedAllocas) {
static void enqueueUsersInWorklist(Instruction &I,
SmallVectorImpl<Instruction *> &Worklist,
- SmallPtrSet<Instruction *, 8> &Visited) {
- for (Value::use_iterator UI = I.use_begin(), UE = I.use_end(); UI != UE;
- ++UI)
- if (Visited.insert(cast<Instruction>(*UI)))
- Worklist.push_back(cast<Instruction>(*UI));
+ SmallPtrSetImpl<Instruction *> &Visited) {
+ for (User *U : I.users())
+ if (Visited.insert(cast<Instruction>(U)).second)
+ Worklist.push_back(cast<Instruction>(U));
}
/// \brief Promote the allocas, using the best available technique.
if (DT && !ForceSSAUpdater) {
DEBUG(dbgs() << "Promoting allocas with mem2reg...\n");
- PromoteMemToReg(PromotableAllocas, *DT);
+ PromoteMemToReg(PromotableAllocas, *DT, nullptr, AC);
PromotableAllocas.clear();
return true;
}
DEBUG(dbgs() << "Promoting allocas with SSAUpdater...\n");
SSAUpdater SSA;
- DIBuilder DIB(*F.getParent());
+ DIBuilder DIB(*F.getParent(), /*AllowUnresolved*/ false);
SmallVector<Instruction *, 64> Insts;
// We need a worklist to walk the uses of each alloca.
return true;
}
-namespace {
- /// \brief A predicate to test whether an alloca belongs to a set.
- class IsAllocaInSet {
- typedef SmallPtrSet<AllocaInst *, 4> SetType;
- const SetType &Set;
-
- public:
- typedef AllocaInst *argument_type;
-
- IsAllocaInSet(const SetType &Set) : Set(Set) {}
- bool operator()(AllocaInst *AI) const { return Set.count(AI); }
- };
-}
-
bool SROA::runOnFunction(Function &F) {
if (skipOptnoneFunction(F))
return false;
DL = &DLP->getDataLayout();
DominatorTreeWrapperPass *DTWP =
getAnalysisIfAvailable<DominatorTreeWrapperPass>();
- DT = DTWP ? &DTWP->getDomTree() : 0;
+ DT = DTWP ? &DTWP->getDomTree() : nullptr;
+ AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+ DbgDeclares.clear();
BasicBlock &EntryBB = F.getEntryBlock();
- for (BasicBlock::iterator I = EntryBB.begin(), E = llvm::prior(EntryBB.end());
- I != E; ++I)
+ for (BasicBlock::iterator I = EntryBB.begin(), E = std::prev(EntryBB.end());
+ I != E; ++I) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
Worklist.insert(AI);
+ else if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I))
+ if (auto AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress()))
+ DbgDeclares.insert(std::make_pair(AI, DDI));
+ }
bool Changed = false;
// A set of deleted alloca instruction pointers which should be removed from
// Remove the deleted allocas from various lists so that we don't try to
// continue processing them.
if (!DeletedAllocas.empty()) {
- Worklist.remove_if(IsAllocaInSet(DeletedAllocas));
- PostPromotionWorklist.remove_if(IsAllocaInSet(DeletedAllocas));
+ auto IsInSet = [&](AllocaInst *AI) { return DeletedAllocas.count(AI); };
+ Worklist.remove_if(IsInSet);
+ PostPromotionWorklist.remove_if(IsInSet);
PromotableAllocas.erase(std::remove_if(PromotableAllocas.begin(),
PromotableAllocas.end(),
- IsAllocaInSet(DeletedAllocas)),
+ IsInSet),
PromotableAllocas.end());
DeletedAllocas.clear();
}
}
void SROA::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<AssumptionCacheTracker>();
if (RequiresDomTree)
AU.addRequired<DominatorTreeWrapperPass>();
AU.setPreservesCFG();