#include "llvm/InstVisitor.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
}
namespace {
-/// \brief A common base class for representing a half-open byte range.
-struct ByteRange {
+/// \brief A partition of an alloca.
+///
+/// This structure represents a contiguous partition of the alloca. These are
+/// formed by examining the uses of the alloca. During formation, they may
+/// overlap but once an AllocaPartitioning is built, the Partitions within it
+/// are all disjoint. The partition also contains a chain of uses of that
+/// partition.
+class Partition {
/// \brief The beginning offset of the range.
uint64_t BeginOffset;
/// \brief The ending offset, not included in the range.
uint64_t EndOffset;
- ByteRange() : BeginOffset(), EndOffset() {}
- ByteRange(uint64_t BeginOffset, uint64_t EndOffset)
- : BeginOffset(BeginOffset), EndOffset(EndOffset) {}
+ /// \brief Storage for both the use of this partition and whether it can be
+ /// split.
+ PointerIntPair<Use *, 1, bool> PartitionUseAndIsSplittable;
+
+public:
+ Partition() : BeginOffset(), EndOffset() {}
+ Partition(uint64_t BeginOffset, uint64_t EndOffset, Use *U, bool IsSplittable)
+ : BeginOffset(BeginOffset), EndOffset(EndOffset),
+ PartitionUseAndIsSplittable(U, IsSplittable) {}
+
+ uint64_t beginOffset() const { return BeginOffset; }
+ uint64_t endOffset() const { return EndOffset; }
+
+ bool isSplittable() const { return PartitionUseAndIsSplittable.getInt(); }
+ void makeUnsplittable() { PartitionUseAndIsSplittable.setInt(false); }
+
+ Use *getUse() const { return PartitionUseAndIsSplittable.getPointer(); }
+
+ bool isDead() const { return getUse() == 0; }
+ void kill() { PartitionUseAndIsSplittable.setPointer(0); }
/// \brief Support for ordering ranges.
///
/// always increasing, and within equal start offsets, the end offsets are
/// decreasing. Thus the spanning range comes first in a cluster with the
/// same start position.
- bool operator<(const ByteRange &RHS) const {
- if (BeginOffset < RHS.BeginOffset) return true;
- if (BeginOffset > RHS.BeginOffset) return false;
- if (EndOffset > RHS.EndOffset) return true;
+ bool operator<(const Partition &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;
return false;
}
/// \brief Support comparison with a single offset to allow binary searches.
- friend bool operator<(const ByteRange &LHS, uint64_t RHSOffset) {
- return LHS.BeginOffset < RHSOffset;
+ friend LLVM_ATTRIBUTE_UNUSED bool operator<(const Partition &LHS,
+ uint64_t RHSOffset) {
+ return LHS.beginOffset() < RHSOffset;
}
-
friend LLVM_ATTRIBUTE_UNUSED bool operator<(uint64_t LHSOffset,
- const ByteRange &RHS) {
- return LHSOffset < RHS.BeginOffset;
- }
-
- bool operator==(const ByteRange &RHS) const {
- return BeginOffset == RHS.BeginOffset && EndOffset == RHS.EndOffset;
- }
- bool operator!=(const ByteRange &RHS) const { return !operator==(RHS); }
-};
-
-/// \brief A partition of an alloca.
-///
-/// This structure represents a contiguous partition of the alloca. These are
-/// formed by examining the uses of the alloca. During formation, they may
-/// overlap but once an AllocaPartitioning is built, the Partitions within it
-/// are all disjoint.
-struct Partition : public ByteRange {
- /// \brief Whether this partition is splittable into smaller partitions.
- ///
- /// We flag partitions as splittable when they are formed entirely due to
- /// accesses by trivially splittable operations such as memset and memcpy.
- bool IsSplittable;
-
- /// \brief Test whether a partition has been marked as dead.
- bool isDead() const {
- if (BeginOffset == UINT64_MAX) {
- assert(EndOffset == UINT64_MAX);
- return true;
- }
- return false;
+ const Partition &RHS) {
+ return LHSOffset < RHS.beginOffset();
}
- /// \brief Kill a partition.
- /// This is accomplished by setting both its beginning and end offset to
- /// the maximum possible value.
- void kill() {
- assert(!isDead() && "He's Dead, Jim!");
- BeginOffset = EndOffset = UINT64_MAX;
+ bool operator==(const Partition &RHS) const {
+ return isSplittable() == RHS.isSplittable() &&
+ beginOffset() == RHS.beginOffset() && endOffset() == RHS.endOffset();
}
-
- Partition() : ByteRange(), IsSplittable() {}
- Partition(uint64_t BeginOffset, uint64_t EndOffset, bool IsSplittable)
- : ByteRange(BeginOffset, EndOffset), IsSplittable(IsSplittable) {}
-};
-
-/// \brief A particular use of a partition of the alloca.
-///
-/// This structure is used to associate uses of a partition with it. They
-/// mark the range of bytes which are referenced by a particular instruction,
-/// and includes a handle to the user itself and the pointer value in use.
-/// The bounds of these uses are determined by intersecting the bounds of the
-/// memory use itself with a particular partition. As a consequence there is
-/// intentionally overlap between various uses of the same partition.
-class PartitionUse : public ByteRange {
- /// \brief Combined storage for both the Use* and split state.
- PointerIntPair<Use*, 1, bool> UsePtrAndIsSplit;
-
-public:
- PartitionUse() : ByteRange(), UsePtrAndIsSplit() {}
- PartitionUse(uint64_t BeginOffset, uint64_t EndOffset, Use *U,
- bool IsSplit)
- : ByteRange(BeginOffset, EndOffset), UsePtrAndIsSplit(U, IsSplit) {}
-
- /// \brief The use in question. Provides access to both user and used value.
- ///
- /// Note that this may be null if the partition use is *dead*, that is, it
- /// should be ignored.
- Use *getUse() const { return UsePtrAndIsSplit.getPointer(); }
-
- /// \brief Set the use for this partition use range.
- void setUse(Use *U) { UsePtrAndIsSplit.setPointer(U); }
-
- /// \brief Whether this use is split across multiple partitions.
- bool isSplit() const { return UsePtrAndIsSplit.getInt(); }
+ bool operator!=(const Partition &RHS) const { return !operator==(RHS); }
};
-}
+} // end anonymous namespace
namespace llvm {
-template <> struct isPodLike<Partition> : llvm::true_type {};
-template <> struct isPodLike<PartitionUse> : llvm::true_type {};
+template <typename T> struct isPodLike;
+template <> struct isPodLike<Partition> {
+ static const bool value = true;
+};
}
namespace {
const_iterator end() const { return Partitions.end(); }
/// @}
- /// \brief Support for iterating over and manipulating a particular
- /// partition's uses.
- ///
- /// The iteration support provided for uses is more limited, but also
- /// includes some manipulation routines to support rewriting the uses of
- /// partitions during SROA.
- /// @{
- typedef SmallVectorImpl<PartitionUse>::iterator use_iterator;
- use_iterator use_begin(unsigned Idx) { return Uses[Idx].begin(); }
- use_iterator use_begin(const_iterator I) { return Uses[I - begin()].begin(); }
- use_iterator use_end(unsigned Idx) { return Uses[Idx].end(); }
- use_iterator use_end(const_iterator I) { return Uses[I - begin()].end(); }
-
- typedef SmallVectorImpl<PartitionUse>::const_iterator const_use_iterator;
- const_use_iterator use_begin(unsigned Idx) const { return Uses[Idx].begin(); }
- const_use_iterator use_begin(const_iterator I) const {
- return Uses[I - begin()].begin();
- }
- const_use_iterator use_end(unsigned Idx) const { return Uses[Idx].end(); }
- const_use_iterator use_end(const_iterator I) const {
- return Uses[I - begin()].end();
- }
-
- unsigned use_size(unsigned Idx) const { return Uses[Idx].size(); }
- unsigned use_size(const_iterator I) const { return Uses[I - begin()].size(); }
- const PartitionUse &getUse(unsigned PIdx, unsigned UIdx) const {
- return Uses[PIdx][UIdx];
- }
- const PartitionUse &getUse(const_iterator I, unsigned UIdx) const {
- return Uses[I - begin()][UIdx];
- }
-
- void use_push_back(unsigned Idx, const PartitionUse &PU) {
- Uses[Idx].push_back(PU);
- }
- void use_push_back(const_iterator I, const PartitionUse &PU) {
- Uses[I - begin()].push_back(PU);
- }
- /// @}
-
/// \brief Allow iterating the dead users for this alloca.
///
/// These are instructions which will never actually use the alloca as they
dead_op_iterator dead_op_end() const { return DeadOperands.end(); }
/// @}
- /// \brief MemTransferInst auxiliary data.
- /// This struct provides some auxiliary data about memory transfer
- /// intrinsics such as memcpy and memmove. These intrinsics can use two
- /// different ranges within the same alloca, and provide other challenges to
- /// correctly represent. We stash extra data to help us untangle this
- /// after the partitioning is complete.
- struct MemTransferOffsets {
- /// The destination begin and end offsets when the destination is within
- /// this alloca. If the end offset is zero the destination is not within
- /// this alloca.
- uint64_t DestBegin, DestEnd;
-
- /// The source begin and end offsets when the source is within this alloca.
- /// If the end offset is zero, the source is not within this alloca.
- uint64_t SourceBegin, SourceEnd;
-
- /// Flag for whether an alloca is splittable.
- bool IsSplittable;
- };
- MemTransferOffsets getMemTransferOffsets(MemTransferInst &II) const {
- return MemTransferInstData.lookup(&II);
- }
-
- /// \brief Map from a PHI or select operand back to a partition.
- ///
- /// When manipulating PHI nodes or selects, they can use more than one
- /// partition of an alloca. We store a special mapping to allow finding the
- /// partition referenced by each of these operands, if any.
- iterator findPartitionForPHIOrSelectOperand(Use *U) {
- SmallDenseMap<Use *, std::pair<unsigned, unsigned> >::const_iterator MapIt
- = PHIOrSelectOpMap.find(U);
- if (MapIt == PHIOrSelectOpMap.end())
- return end();
-
- return begin() + MapIt->second.first;
- }
-
- /// \brief Map from a PHI or select operand back to the specific use of
- /// a partition.
- ///
- /// Similar to mapping these operands back to the partitions, this maps
- /// directly to the use structure of that partition.
- use_iterator findPartitionUseForPHIOrSelectOperand(Use *U) {
- SmallDenseMap<Use *, std::pair<unsigned, unsigned> >::const_iterator MapIt
- = PHIOrSelectOpMap.find(U);
- assert(MapIt != PHIOrSelectOpMap.end());
- return Uses[MapIt->second.first].begin() + MapIt->second.second;
- }
-
- /// \brief Compute a common type among the uses of a particular partition.
- ///
- /// This routines walks all of the uses of a particular partition and tries
- /// to find a common type between them. Untyped operations such as memset and
- /// memcpy are ignored.
- Type *getCommonType(iterator I) const;
-
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void print(raw_ostream &OS, const_iterator I, StringRef Indent = " ") const;
- void printUsers(raw_ostream &OS, const_iterator I,
- StringRef Indent = " ") const;
+ void printPartition(raw_ostream &OS, const_iterator I,
+ StringRef Indent = " ") const;
+ void printUse(raw_ostream &OS, const_iterator I,
+ StringRef Indent = " ") const;
void print(raw_ostream &OS) const;
void LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED dump(const_iterator I) const;
void LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED dump() const;
template <typename DerivedT, typename RetT = void> class BuilderBase;
class PartitionBuilder;
friend class AllocaPartitioning::PartitionBuilder;
- class UseBuilder;
- friend class AllocaPartitioning::UseBuilder;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
/// \brief Handle to alloca instruction to simplify method interfaces.
/// expected to always have this as a disjoint space.
SmallVector<Partition, 8> Partitions;
- /// \brief The uses of the partitions.
- ///
- /// This is essentially a mapping from each partition to a list of uses of
- /// that partition. The mapping is done with a Uses vector that has the exact
- /// same number of entries as the partition vector. Each entry is itself
- /// a vector of the uses.
- SmallVector<SmallVector<PartitionUse, 2>, 8> Uses;
-
/// \brief Instructions which will become dead if we rewrite the alloca.
///
/// Note that these are not separated by partition. This is because we expect
/// want to swap this particular input for undef to simplify the use lists of
/// the alloca.
SmallVector<Use *, 8> DeadOperands;
-
- /// \brief The underlying storage for auxiliary memcpy and memset info.
- SmallDenseMap<MemTransferInst *, MemTransferOffsets, 4> MemTransferInstData;
-
- /// \brief A side datastructure used when building up the partitions and uses.
- ///
- /// This mapping is only really used during the initial building of the
- /// partitioning so that we can retain information about PHI and select nodes
- /// processed.
- SmallDenseMap<Instruction *, std::pair<uint64_t, bool> > PHIOrSelectSizes;
-
- /// \brief Auxiliary information for particular PHI or select operands.
- SmallDenseMap<Use *, std::pair<unsigned, unsigned>, 4> PHIOrSelectOpMap;
-
- /// \brief A utility routine called from the constructor.
- ///
- /// This does what it says on the tin. It is the key of the alloca partition
- /// splitting and merging. After it is called we have the desired disjoint
- /// collection of partitions.
- void splitAndMergePartitions();
};
}
AllocaPartitioning &P;
SmallDenseMap<Instruction *, unsigned> MemTransferPartitionMap;
+ SmallDenseMap<Instruction *, uint64_t> PHIOrSelectSizes;
+
+ /// \brief Set to de-duplicate dead instructions found in the use walk.
+ SmallPtrSet<Instruction *, 4> VisitedDeadInsts;
public:
PartitionBuilder(const DataLayout &DL, AllocaInst &AI, AllocaPartitioning &P)
P(P) {}
private:
+ void markAsDead(Instruction &I) {
+ if (VisitedDeadInsts.insert(&I))
+ P.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
<< AllocSize << " byte alloca:\n"
<< " alloca: " << P.AI << "\n"
<< " use: " << I << "\n");
- return;
+ return markAsDead(I);
}
uint64_t BeginOffset = Offset.getZExtValue();
EndOffset = AllocSize;
}
- Partition New(BeginOffset, EndOffset, IsSplittable);
- P.Partitions.push_back(New);
+ P.Partitions.push_back(Partition(BeginOffset, EndOffset, U, IsSplittable));
+ }
+
+ void visitBitCastInst(BitCastInst &BC) {
+ if (BC.use_empty())
+ return markAsDead(BC);
+
+ return Base::visitBitCastInst(BC);
+ }
+
+ void visitGetElementPtrInst(GetElementPtrInst &GEPI) {
+ if (GEPI.use_empty())
+ return markAsDead(GEPI);
+
+ return Base::visitGetElementPtrInst(GEPI);
}
void handleLoadOrStore(Type *Ty, Instruction &I, const APInt &Offset,
<< " byte alloca:\n"
<< " alloca: " << P.AI << "\n"
<< " use: " << SI << "\n");
- return;
+ return markAsDead(SI);
}
assert((!SI.isSimple() || ValOp->getType()->isSingleValueType()) &&
if ((Length && Length->getValue() == 0) ||
(IsOffsetKnown && !Offset.isNegative() && Offset.uge(AllocSize)))
// Zero-length mem transfer intrinsics can be ignored entirely.
- return;
+ return markAsDead(II);
if (!IsOffsetKnown)
return PI.setAborted(&II);
if ((Length && Length->getValue() == 0) ||
(IsOffsetKnown && !Offset.isNegative() && Offset.uge(AllocSize)))
// Zero-length mem transfer intrinsics can be ignored entirely.
- return;
+ return markAsDead(II);
if (!IsOffsetKnown)
return PI.setAborted(&II);
uint64_t Size = Length ? Length->getLimitedValue()
: AllocSize - RawOffset;
- MemTransferOffsets &Offsets = P.MemTransferInstData[&II];
-
- // Only intrinsics with a constant length can be split.
- Offsets.IsSplittable = Length;
+ // Check for the special case where the same exact value is used for both
+ // source and dest.
+ if (*U == II.getRawDest() && *U == II.getRawSource()) {
+ // For non-volatile transfers this is a no-op.
+ if (!II.isVolatile())
+ return markAsDead(II);
- if (*U == II.getRawDest()) {
- Offsets.DestBegin = RawOffset;
- Offsets.DestEnd = RawOffset + Size;
- }
- if (*U == II.getRawSource()) {
- Offsets.SourceBegin = RawOffset;
- Offsets.SourceEnd = RawOffset + Size;
+ return insertUse(II, Offset, Size, /*IsSplittable=*/false);;
}
- // If we have set up end offsets for both the source and the destination,
- // we have found both sides of this transfer pointing at the same alloca.
- bool SeenBothEnds = Offsets.SourceEnd && Offsets.DestEnd;
- if (SeenBothEnds && II.getRawDest() != II.getRawSource()) {
- unsigned PrevIdx = MemTransferPartitionMap[&II];
+ // If we have seen both source and destination for a mem transfer, then
+ // they both point to the same alloca.
+ bool Inserted;
+ SmallDenseMap<Instruction *, unsigned>::iterator MTPI;
+ llvm::tie(MTPI, Inserted) =
+ MemTransferPartitionMap.insert(std::make_pair(&II, P.Partitions.size()));
+ unsigned PrevIdx = MTPI->second;
+ if (!Inserted) {
+ Partition &PrevP = P.Partitions[PrevIdx];
// Check if the begin offsets match and this is a non-volatile transfer.
// In that case, we can completely elide the transfer.
- if (!II.isVolatile() && Offsets.SourceBegin == Offsets.DestBegin) {
- P.Partitions[PrevIdx].kill();
- return;
+ if (!II.isVolatile() && PrevP.beginOffset() == RawOffset) {
+ PrevP.kill();
+ return markAsDead(II);
}
// Otherwise we have an offset transfer within the same alloca. We can't
// split those.
- P.Partitions[PrevIdx].IsSplittable = Offsets.IsSplittable = false;
- } else if (SeenBothEnds) {
- // Handle the case where this exact use provides both ends of the
- // operation.
- assert(II.getRawDest() == II.getRawSource());
-
- // For non-volatile transfers this is a no-op.
- if (!II.isVolatile())
- return;
-
- // Otherwise just suppress splitting.
- Offsets.IsSplittable = false;
+ PrevP.makeUnsplittable();
}
-
// Insert the use now that we've fixed up the splittable nature.
- insertUse(II, Offset, Size, Offsets.IsSplittable);
-
- // Setup the mapping from intrinsic to partition of we've not seen both
- // ends of this transfer.
- if (!SeenBothEnds) {
- unsigned NewIdx = P.Partitions.size() - 1;
- bool Inserted
- = MemTransferPartitionMap.insert(std::make_pair(&II, NewIdx)).second;
- assert(Inserted &&
- "Already have intrinsic in map but haven't seen both ends");
- (void)Inserted;
- }
+ insertUse(II, Offset, Size, /*IsSplittable=*/Inserted && Length);
+
+ // Check that we ended up with a valid index in the map.
+ assert(P.Partitions[PrevIdx].getUse()->getUser() == &II &&
+ "Map index doesn't point back to a partition with this user.");
}
// Disable SRoA for any intrinsics except for lifetime invariants.
void visitPHINode(PHINode &PN) {
if (PN.use_empty())
- return;
+ return markAsDead(PN);
if (!IsOffsetKnown)
return PI.setAborted(&PN);
// See if we already have computed info on this node.
- std::pair<uint64_t, bool> &PHIInfo = P.PHIOrSelectSizes[&PN];
- if (PHIInfo.first) {
- PHIInfo.second = true;
- insertUse(PN, Offset, PHIInfo.first);
- return;
- }
-
- // Check for an unsafe use of the PHI node.
- if (Instruction *UnsafeI = hasUnsafePHIOrSelectUse(&PN, PHIInfo.first))
- return PI.setAborted(UnsafeI);
-
- insertUse(PN, Offset, PHIInfo.first);
- }
-
- void visitSelectInst(SelectInst &SI) {
- if (SI.use_empty())
- return;
- if (Value *Result = foldSelectInst(SI)) {
- if (Result == *U)
- // If the result of the constant fold will be the pointer, recurse
- // through the select as if we had RAUW'ed it.
- enqueueUsers(SI);
-
- return;
- }
- if (!IsOffsetKnown)
- return PI.setAborted(&SI);
-
- // See if we already have computed info on this node.
- std::pair<uint64_t, bool> &SelectInfo = P.PHIOrSelectSizes[&SI];
- if (SelectInfo.first) {
- SelectInfo.second = true;
- insertUse(SI, Offset, SelectInfo.first);
- return;
- }
-
- // Check for an unsafe use of the PHI node.
- if (Instruction *UnsafeI = hasUnsafePHIOrSelectUse(&SI, SelectInfo.first))
- return PI.setAborted(UnsafeI);
-
- insertUse(SI, Offset, SelectInfo.first);
- }
-
- /// \brief Disable SROA entirely if there are unhandled users of the alloca.
- void visitInstruction(Instruction &I) {
- PI.setAborted(&I);
- }
-};
-
-/// \brief Use adder for the alloca partitioning.
-///
-/// This class adds the uses of an alloca to all of the partitions which they
-/// use. For splittable partitions, this can end up doing essentially a linear
-/// walk of the partitions, but the number of steps remains bounded by the
-/// total result instruction size:
-/// - The number of partitions is a result of the number unsplittable
-/// instructions using the alloca.
-/// - The number of users of each partition is at worst the total number of
-/// splittable instructions using the alloca.
-/// Thus we will produce N * M instructions in the end, where N are the number
-/// of unsplittable uses and M are the number of splittable. This visitor does
-/// the exact same number of updates to the partitioning.
-///
-/// In the more common case, this visitor will leverage the fact that the
-/// partition space is pre-sorted, and do a logarithmic search for the
-/// partition needed, making the total visit a classical ((N + M) * log(N))
-/// complexity operation.
-class AllocaPartitioning::UseBuilder : public PtrUseVisitor<UseBuilder> {
- friend class PtrUseVisitor<UseBuilder>;
- friend class InstVisitor<UseBuilder>;
- typedef PtrUseVisitor<UseBuilder> Base;
-
- const uint64_t AllocSize;
- AllocaPartitioning &P;
-
- /// \brief Set to de-duplicate dead instructions found in the use walk.
- SmallPtrSet<Instruction *, 4> VisitedDeadInsts;
-
-public:
- UseBuilder(const DataLayout &TD, AllocaInst &AI, AllocaPartitioning &P)
- : PtrUseVisitor<UseBuilder>(TD),
- AllocSize(TD.getTypeAllocSize(AI.getAllocatedType())),
- P(P) {}
-
-private:
- void markAsDead(Instruction &I) {
- if (VisitedDeadInsts.insert(&I))
- P.DeadUsers.push_back(&I);
- }
-
- void insertUse(Instruction &User, const APInt &Offset, uint64_t Size) {
- // If the use has a zero size or extends outside of the allocation, record
- // it as a dead use for elimination later.
- if (Size == 0 || Offset.isNegative() || Offset.uge(AllocSize))
- return markAsDead(User);
-
- uint64_t BeginOffset = Offset.getZExtValue();
- uint64_t EndOffset = BeginOffset + Size;
-
- // Clamp the end offset to the end of the allocation. Note that this is
- // formulated to handle even the case where "BeginOffset + Size" overflows.
- assert(AllocSize >= BeginOffset); // Established above.
- if (Size > AllocSize - BeginOffset)
- EndOffset = AllocSize;
-
- // NB: This only works if we have zero overlapping partitions.
- iterator I = std::lower_bound(P.begin(), P.end(), BeginOffset);
- if (I != P.begin() && llvm::prior(I)->EndOffset > BeginOffset)
- I = llvm::prior(I);
- iterator E = P.end();
- bool IsSplit = llvm::next(I) != E && llvm::next(I)->BeginOffset < EndOffset;
- for (; I != E && I->BeginOffset < EndOffset; ++I) {
- PartitionUse NewPU(std::max(I->BeginOffset, BeginOffset),
- std::min(I->EndOffset, EndOffset), U, IsSplit);
- P.use_push_back(I, NewPU);
- if (isa<PHINode>(U->getUser()) || isa<SelectInst>(U->getUser()))
- P.PHIOrSelectOpMap[U]
- = std::make_pair(I - P.begin(), P.Uses[I - P.begin()].size() - 1);
+ 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);
}
- }
-
- void visitBitCastInst(BitCastInst &BC) {
- if (BC.use_empty())
- return markAsDead(BC);
-
- return Base::visitBitCastInst(BC);
- }
-
- void visitGetElementPtrInst(GetElementPtrInst &GEPI) {
- if (GEPI.use_empty())
- return markAsDead(GEPI);
-
- return Base::visitGetElementPtrInst(GEPI);
- }
-
- void visitLoadInst(LoadInst &LI) {
- assert(IsOffsetKnown);
- uint64_t Size = DL.getTypeStoreSize(LI.getType());
- insertUse(LI, Offset, Size);
- }
-
- void visitStoreInst(StoreInst &SI) {
- assert(IsOffsetKnown);
- uint64_t Size = DL.getTypeStoreSize(SI.getOperand(0)->getType());
-
- // If this memory access can be shown to *statically* extend outside the
- // bounds of of the allocation, it's behavior is undefined, so simply
- // ignore it. Note that this is more strict than the generic clamping
- // behavior of insertUse.
- if (Offset.isNegative() || Size > AllocSize ||
- Offset.ugt(AllocSize - Size))
- return markAsDead(SI);
-
- insertUse(SI, Offset, Size);
- }
-
- void visitMemSetInst(MemSetInst &II) {
- ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
- if ((Length && Length->getValue() == 0) ||
- (IsOffsetKnown && !Offset.isNegative() && Offset.uge(AllocSize)))
- return markAsDead(II);
-
- assert(IsOffsetKnown);
- insertUse(II, Offset, Length ? Length->getLimitedValue()
- : AllocSize - Offset.getLimitedValue());
- }
-
- void visitMemTransferInst(MemTransferInst &II) {
- ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
- if ((Length && Length->getValue() == 0) ||
- (IsOffsetKnown && !Offset.isNegative() && Offset.uge(AllocSize)))
- return markAsDead(II);
-
- assert(IsOffsetKnown);
- uint64_t Size = Length ? Length->getLimitedValue()
- : AllocSize - Offset.getLimitedValue();
-
- const MemTransferOffsets &Offsets = P.MemTransferInstData[&II];
- if (!II.isVolatile() && Offsets.DestEnd && Offsets.SourceEnd &&
- Offsets.DestBegin == Offsets.SourceBegin)
- return markAsDead(II); // Skip identity transfers without side-effects.
-
- insertUse(II, Offset, Size);
- }
-
- void visitIntrinsicInst(IntrinsicInst &II) {
- assert(IsOffsetKnown);
- assert(II.getIntrinsicID() == Intrinsic::lifetime_start ||
- II.getIntrinsicID() == Intrinsic::lifetime_end);
-
- ConstantInt *Length = cast<ConstantInt>(II.getArgOperand(0));
- insertUse(II, Offset, std::min(Length->getLimitedValue(),
- AllocSize - Offset.getLimitedValue()));
- }
-
- void insertPHIOrSelect(Instruction &User, const APInt &Offset) {
- uint64_t Size = P.PHIOrSelectSizes.lookup(&User).first;
// For PHI and select operands outside the alloca, we can't nuke the entire
// phi or select -- the other side might still be relevant, so we special
// case them here and use a separate structure to track the operands
// themselves which should be replaced with undef.
- if ((Offset.isNegative() && Offset.uge(Size)) ||
+ // 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))) {
P.DeadOperands.push_back(U);
return;
}
- insertUse(User, Offset, Size);
- }
-
- void visitPHINode(PHINode &PN) {
- if (PN.use_empty())
- return markAsDead(PN);
-
- assert(IsOffsetKnown);
- insertPHIOrSelect(PN, Offset);
+ insertUse(PN, Offset, PHISize);
}
void visitSelectInst(SelectInst &SI) {
if (SI.use_empty())
return markAsDead(SI);
-
if (Value *Result = foldSelectInst(SI)) {
if (Result == *U)
// If the result of the constant fold will be the pointer, recurse
return;
}
+ if (!IsOffsetKnown)
+ return PI.setAborted(&SI);
- assert(IsOffsetKnown);
- insertPHIOrSelect(SI, Offset);
- }
-
- /// \brief Unreachable, we've already visited the alloca once.
- void visitInstruction(Instruction &I) {
- llvm_unreachable("Unhandled instruction in use builder.");
- }
-};
-
-void AllocaPartitioning::splitAndMergePartitions() {
- size_t NumDeadPartitions = 0;
-
- // Track the range of splittable partitions that we pass when accumulating
- // overlapping unsplittable partitions.
- uint64_t SplitEndOffset = 0ull;
-
- Partition New(0ull, 0ull, false);
-
- for (unsigned i = 0, j = i, e = Partitions.size(); i != e; i = j) {
- ++j;
-
- if (!Partitions[i].IsSplittable || New.BeginOffset == New.EndOffset) {
- assert(New.BeginOffset == New.EndOffset);
- New = Partitions[i];
- } else {
- assert(New.IsSplittable);
- New.EndOffset = std::max(New.EndOffset, Partitions[i].EndOffset);
- }
- assert(New.BeginOffset != New.EndOffset);
-
- // Scan the overlapping partitions.
- while (j != e && New.EndOffset > Partitions[j].BeginOffset) {
- // If the new partition we are forming is splittable, stop at the first
- // unsplittable partition.
- if (New.IsSplittable && !Partitions[j].IsSplittable)
- break;
-
- // Grow the new partition to include any equally splittable range. 'j' is
- // always equally splittable when New is splittable, but when New is not
- // splittable, we may subsume some (or part of some) splitable partition
- // without growing the new one.
- if (New.IsSplittable == Partitions[j].IsSplittable) {
- New.EndOffset = std::max(New.EndOffset, Partitions[j].EndOffset);
- } else {
- assert(!New.IsSplittable);
- assert(Partitions[j].IsSplittable);
- SplitEndOffset = std::max(SplitEndOffset, Partitions[j].EndOffset);
- }
-
- Partitions[j].kill();
- ++NumDeadPartitions;
- ++j;
- }
-
- // If the new partition is splittable, chop off the end as soon as the
- // unsplittable subsequent partition starts and ensure we eventually cover
- // the splittable area.
- if (j != e && New.IsSplittable) {
- SplitEndOffset = std::max(SplitEndOffset, New.EndOffset);
- New.EndOffset = std::min(New.EndOffset, Partitions[j].BeginOffset);
+ // 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))
+ return PI.setAborted(UnsafeI);
}
- // Add the new partition if it differs from the original one and is
- // non-empty. We can end up with an empty partition here if it was
- // splittable but there is an unsplittable one that starts at the same
- // offset.
- if (New != Partitions[i]) {
- if (New.BeginOffset != New.EndOffset)
- Partitions.push_back(New);
- // Mark the old one for removal.
- Partitions[i].kill();
- ++NumDeadPartitions;
+ // 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(SelectSize)) ||
+ (!Offset.isNegative() && Offset.uge(AllocSize))) {
+ P.DeadOperands.push_back(U);
+ return;
}
- New.BeginOffset = New.EndOffset;
- if (!New.IsSplittable) {
- New.EndOffset = std::max(New.EndOffset, SplitEndOffset);
- if (j != e && !Partitions[j].IsSplittable)
- New.EndOffset = std::min(New.EndOffset, Partitions[j].BeginOffset);
- New.IsSplittable = true;
- // If there is a trailing splittable partition which won't be fused into
- // the next splittable partition go ahead and add it onto the partitions
- // list.
- if (New.BeginOffset < New.EndOffset &&
- (j == e || !Partitions[j].IsSplittable ||
- New.EndOffset < Partitions[j].BeginOffset)) {
- Partitions.push_back(New);
- New.BeginOffset = New.EndOffset = 0ull;
- }
- }
+ insertUse(SI, Offset, SelectSize);
}
- // Re-sort the partitions now that they have been split and merged into
- // disjoint set of partitions. Also remove any of the dead partitions we've
- // replaced in the process.
- std::sort(Partitions.begin(), Partitions.end());
- if (NumDeadPartitions) {
- assert(Partitions.back().isDead());
- assert((ptrdiff_t)NumDeadPartitions ==
- std::count(Partitions.begin(), Partitions.end(), Partitions.back()));
+ /// \brief Disable SROA entirely if there are unhandled users of the alloca.
+ void visitInstruction(Instruction &I) {
+ PI.setAborted(&I);
}
- Partitions.erase(Partitions.end() - NumDeadPartitions, Partitions.end());
+};
+
+namespace {
+struct IsPartitionDead {
+ bool operator()(const Partition &P) { return P.isDead(); }
+};
}
AllocaPartitioning::AllocaPartitioning(const DataLayout &TD, AllocaInst &AI)
// and the sizes to be in descending order.
std::sort(Partitions.begin(), Partitions.end());
- // Remove any partitions from the back which are marked as dead.
- while (!Partitions.empty() && Partitions.back().isDead())
- Partitions.pop_back();
-
- if (Partitions.size() > 1) {
- // Intersect splittability for all partitions with equal offsets and sizes.
- // Then remove all but the first so that we have a sequence of non-equal but
- // potentially overlapping partitions.
- for (iterator I = Partitions.begin(), J = I, E = Partitions.end(); I != E;
- I = J) {
- ++J;
- while (J != E && *I == *J) {
- I->IsSplittable &= J->IsSplittable;
- ++J;
- }
- }
- Partitions.erase(std::unique(Partitions.begin(), Partitions.end()),
- Partitions.end());
-
- // Split splittable and merge unsplittable partitions into a disjoint set
- // of partitions over the used space of the allocation.
- splitAndMergePartitions();
- }
+ Partitions.erase(
+ std::remove_if(Partitions.begin(), Partitions.end(), IsPartitionDead()),
+ Partitions.end());
// Record how many partitions we end up with.
NumAllocaPartitions += Partitions.size();
MaxPartitionsPerAlloca = std::max<unsigned>(Partitions.size(), MaxPartitionsPerAlloca);
- // Now build up the user lists for each of these disjoint partitions by
- // re-walking the recursive users of the alloca.
- Uses.resize(Partitions.size());
- UseBuilder UB(TD, AI, *this);
- PtrI = UB.visitPtr(AI);
- assert(!PtrI.isEscaped() && "Previously analyzed pointer now escapes!");
- assert(!PtrI.isAborted() && "Early aborted the visit of the pointer.");
-
- unsigned NumUses = 0;
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
- for (unsigned Idx = 0, Size = Uses.size(); Idx != Size; ++Idx)
- NumUses += Uses[Idx].size();
-#endif
- NumAllocaPartitionUses += NumUses;
- MaxPartitionUsesPerAlloca = std::max<unsigned>(NumUses, MaxPartitionUsesPerAlloca);
-}
-
-Type *AllocaPartitioning::getCommonType(iterator I) const {
- Type *Ty = 0;
- for (const_use_iterator UI = use_begin(I), UE = use_end(I); UI != UE; ++UI) {
- Use *U = UI->getUse();
- if (!U)
- continue; // Skip dead uses.
- if (isa<IntrinsicInst>(*U->getUser()))
- continue;
- if (UI->BeginOffset != I->BeginOffset || UI->EndOffset != I->EndOffset)
- continue;
-
- Type *UserTy = 0;
- if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser()))
- UserTy = LI->getType();
- else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser()))
- UserTy = SI->getValueOperand()->getType();
- else
- return 0; // Bail if we have weird uses.
-
- if (IntegerType *ITy = dyn_cast<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
- // entity causing the split.
- if (ITy->getBitWidth() > (I->EndOffset - I->BeginOffset)*8)
- continue;
-
- // If we have found an integer type use covering the alloca, use that
- // regardless of the other types, as integers are often used for a "bucket
- // of bits" type.
- return ITy;
- }
-
- if (Ty && Ty != UserTy)
- return 0;
-
- Ty = UserTy;
- }
- return Ty;
+ NumAllocaPartitionUses += Partitions.size();
+ MaxPartitionUsesPerAlloca =
+ std::max<unsigned>(Partitions.size(), MaxPartitionUsesPerAlloca);
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void AllocaPartitioning::print(raw_ostream &OS, const_iterator I,
StringRef Indent) const {
- OS << Indent << "partition #" << (I - begin())
- << " [" << I->BeginOffset << "," << I->EndOffset << ")"
- << (I->IsSplittable ? " (splittable)" : "")
- << (Uses[I - begin()].empty() ? " (zero uses)" : "")
- << "\n";
+ printPartition(OS, I, Indent);
+ printUse(OS, I, Indent);
+}
+
+void AllocaPartitioning::printPartition(raw_ostream &OS, const_iterator I,
+ StringRef Indent) const {
+ OS << Indent << "[" << I->beginOffset() << "," << I->endOffset() << ")"
+ << " partition #" << (I - begin())
+ << (I->isSplittable() ? " (splittable)" : "") << "\n";
}
-void AllocaPartitioning::printUsers(raw_ostream &OS, const_iterator I,
- StringRef Indent) const {
- for (const_use_iterator UI = use_begin(I), UE = use_end(I); UI != UE; ++UI) {
- if (!UI->getUse())
- continue; // Skip dead uses.
- OS << Indent << " [" << UI->BeginOffset << "," << UI->EndOffset << ") "
- << "used by: " << *UI->getUse()->getUser() << "\n";
- if (MemTransferInst *II =
- dyn_cast<MemTransferInst>(UI->getUse()->getUser())) {
- const MemTransferOffsets &MTO = MemTransferInstData.lookup(II);
- bool IsDest;
- if (!MTO.IsSplittable)
- IsDest = UI->BeginOffset == MTO.DestBegin;
- else
- IsDest = MTO.DestBegin != 0u;
- OS << Indent << " (original " << (IsDest ? "dest" : "source") << ": "
- << "[" << (IsDest ? MTO.DestBegin : MTO.SourceBegin)
- << "," << (IsDest ? MTO.DestEnd : MTO.SourceEnd) << ")\n";
- }
- }
+void AllocaPartitioning::printUse(raw_ostream &OS, const_iterator I,
+ StringRef Indent) const {
+ OS << Indent << " used by: " << *I->getUse()->getUser() << "\n";
}
void AllocaPartitioning::print(raw_ostream &OS) const {
}
OS << "Partitioning of alloca: " << AI << "\n";
- for (const_iterator I = begin(), E = end(); I != E; ++I) {
+ for (const_iterator I = begin(), E = end(); I != E; ++I)
print(OS, I);
- printUsers(OS, I);
- }
}
void AllocaPartitioning::dump(const_iterator I) const { print(dbgs(), I); }
#endif // !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-
namespace {
/// \brief Implementation of LoadAndStorePromoter for promoting allocas.
///
/// \brief A collection of alloca instructions we can directly promote.
std::vector<AllocaInst *> PromotableAllocas;
+ /// \brief A worklist of PHIs to speculate prior to promoting allocas.
+ ///
+ /// 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;
+
+ /// \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;
+
public:
SROA(bool RequiresDomTree = true)
: FunctionPass(ID), RequiresDomTree(RequiresDomTree),
friend class AllocaPartitionRewriter;
friend class AllocaPartitionVectorRewriter;
- bool rewriteAllocaPartition(AllocaInst &AI,
- AllocaPartitioning &P,
- AllocaPartitioning::iterator PI);
+ bool rewritePartitions(AllocaInst &AI, AllocaPartitioning &P,
+ AllocaPartitioning::iterator B,
+ AllocaPartitioning::iterator E,
+ int64_t BeginOffset, int64_t EndOffset,
+ ArrayRef<AllocaPartitioning::iterator> SplitUses);
bool splitAlloca(AllocaInst &AI, AllocaPartitioning &P);
bool runOnAlloca(AllocaInst &AI);
void deleteDeadInstructions(SmallPtrSet<AllocaInst *, 4> &DeletedAllocas);
INITIALIZE_PASS_END(SROA, "sroa", "Scalar Replacement Of Aggregates",
false, false)
-namespace {
-/// \brief Visitor to speculate PHIs and Selects where possible.
-class PHIOrSelectSpeculator : public InstVisitor<PHIOrSelectSpeculator> {
- // Befriend the base class so it can delegate to private visit methods.
- friend class llvm::InstVisitor<PHIOrSelectSpeculator>;
+/// Walk a range of a partitioning looking for a common type to cover this
+/// sequence of partition uses.
+static Type *findCommonType(AllocaPartitioning::const_iterator B,
+ AllocaPartitioning::const_iterator E,
+ uint64_t EndOffset) {
+ Type *Ty = 0;
+ for (AllocaPartitioning::const_iterator I = B; I != E; ++I) {
+ Use *U = I->getUse();
+ if (isa<IntrinsicInst>(*U->getUser()))
+ continue;
+ if (I->beginOffset() != B->beginOffset() || I->endOffset() != EndOffset)
+ continue;
- const DataLayout &TD;
- AllocaPartitioning &P;
- SROA &Pass;
+ Type *UserTy = 0;
+ if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser()))
+ UserTy = LI->getType();
+ else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser()))
+ UserTy = SI->getValueOperand()->getType();
+ else
+ return 0; // Bail if we have weird uses.
-public:
- PHIOrSelectSpeculator(const DataLayout &TD, AllocaPartitioning &P, SROA &Pass)
- : TD(TD), P(P), Pass(Pass) {}
-
- /// \brief Visit the users of an alloca partition and rewrite them.
- void visitUsers(AllocaPartitioning::const_iterator PI) {
- // Note that we need to use an index here as the underlying vector of uses
- // may be grown during speculation. However, we never need to re-visit the
- // new uses, and so we can use the initial size bound.
- for (unsigned Idx = 0, Size = P.use_size(PI); Idx != Size; ++Idx) {
- const PartitionUse &PU = P.getUse(PI, Idx);
- if (!PU.getUse())
- continue; // Skip dead use.
-
- visit(cast<Instruction>(PU.getUse()->getUser()));
- }
- }
+ if (IntegerType *ITy = dyn_cast<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
+ // entity causing the split.
+ if (ITy->getBitWidth() / 8 > (EndOffset - B->beginOffset()))
+ continue;
-private:
- // By default, skip this instruction.
- void visitInstruction(Instruction &I) {}
-
- /// PHI instructions that use an alloca and are subsequently loaded can be
- /// rewritten to load both input pointers in the pred blocks and then PHI the
- /// results, allowing the load of the alloca to be promoted.
- /// From this:
- /// %P2 = phi [i32* %Alloca, i32* %Other]
- /// %V = load i32* %P2
- /// to:
- /// %V1 = load i32* %Alloca -> will be mem2reg'd
- /// ...
- /// %V2 = load i32* %Other
- /// ...
- /// %V = phi [i32 %V1, i32 %V2]
- ///
- /// We can do this to a select if its only uses are loads and if the operands
- /// to the select can be loaded unconditionally.
- ///
- /// FIXME: This should be hoisted into a generic utility, likely in
- /// Transforms/Util/Local.h
- bool isSafePHIToSpeculate(PHINode &PN, SmallVectorImpl<LoadInst *> &Loads) {
- // For now, we can only do this promotion if the load is in the same block
- // as the PHI, and if there are no stores between the phi and load.
- // TODO: Allow recursive phi users.
- // TODO: Allow stores.
- BasicBlock *BB = PN.getParent();
- unsigned MaxAlign = 0;
- for (Value::use_iterator UI = PN.use_begin(), UE = PN.use_end();
- UI != UE; ++UI) {
- LoadInst *LI = dyn_cast<LoadInst>(*UI);
- if (LI == 0 || !LI->isSimple()) return false;
-
- // For now we only allow loads in the same block as the PHI. This is
- // a common case that happens when instcombine merges two loads through
- // a PHI.
- if (LI->getParent() != BB) return false;
-
- // Ensure that there are no instructions between the PHI and the load that
- // could store.
- for (BasicBlock::iterator BBI = &PN; &*BBI != LI; ++BBI)
- if (BBI->mayWriteToMemory())
- return false;
-
- MaxAlign = std::max(MaxAlign, LI->getAlignment());
- Loads.push_back(LI);
+ // If we have found an integer type use covering the alloca, use that
+ // regardless of the other types, as integers are often used for a
+ // "bucket
+ // of bits" type.
+ return ITy;
}
- // We can only transform this if it is safe to push the loads into the
- // predecessor blocks. The only thing to watch out for is that we can't put
- // a possibly trapping load in the predecessor if it is a critical edge.
- for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
- TerminatorInst *TI = PN.getIncomingBlock(Idx)->getTerminator();
- Value *InVal = PN.getIncomingValue(Idx);
-
- // If the value is produced by the terminator of the predecessor (an
- // invoke) or it has side-effects, there is no valid place to put a load
- // in the predecessor.
- if (TI == InVal || TI->mayHaveSideEffects())
- return false;
+ if (Ty && Ty != UserTy)
+ return 0;
- // If the predecessor has a single successor, then the edge isn't
- // critical.
- if (TI->getNumSuccessors() == 1)
- continue;
+ Ty = UserTy;
+ }
+ return Ty;
+}
- // If this pointer is always safe to load, or if we can prove that there
- // is already a load in the block, then we can move the load to the pred
- // block.
- if (InVal->isDereferenceablePointer() ||
- isSafeToLoadUnconditionally(InVal, TI, MaxAlign, &TD))
- continue;
+/// PHI instructions that use an alloca and are subsequently loaded can be
+/// rewritten to load both input pointers in the pred blocks and then PHI the
+/// results, allowing the load of the alloca to be promoted.
+/// From this:
+/// %P2 = phi [i32* %Alloca, i32* %Other]
+/// %V = load i32* %P2
+/// to:
+/// %V1 = load i32* %Alloca -> will be mem2reg'd
+/// ...
+/// %V2 = load i32* %Other
+/// ...
+/// %V = phi [i32 %V1, i32 %V2]
+///
+/// We can do this to a select if its only uses are loads and if the operands
+/// to the select can be loaded unconditionally.
+///
+/// FIXME: This should be hoisted into a generic utility, likely in
+/// Transforms/Util/Local.h
+static bool isSafePHIToSpeculate(PHINode &PN,
+ const DataLayout *TD = 0) {
+ // For now, we can only do this promotion if the load is in the same block
+ // as the PHI, and if there are no stores between the phi and load.
+ // TODO: Allow recursive phi users.
+ // TODO: Allow stores.
+ BasicBlock *BB = PN.getParent();
+ unsigned MaxAlign = 0;
+ 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())
+ return false;
+ // For now we only allow loads in the same block as the PHI. This is
+ // a common case that happens when instcombine merges two loads through
+ // a PHI.
+ if (LI->getParent() != BB)
return false;
- }
- return true;
+ // Ensure that there are no instructions between the PHI and the load that
+ // could store.
+ for (BasicBlock::iterator BBI = &PN; &*BBI != LI; ++BBI)
+ if (BBI->mayWriteToMemory())
+ return false;
+
+ MaxAlign = std::max(MaxAlign, LI->getAlignment());
+ HaveLoad = true;
}
- void visitPHINode(PHINode &PN) {
- DEBUG(dbgs() << " original: " << PN << "\n");
+ if (!HaveLoad)
+ return false;
- SmallVector<LoadInst *, 4> Loads;
- if (!isSafePHIToSpeculate(PN, Loads))
- return;
+ // We can only transform this if it is safe to push the loads into the
+ // predecessor blocks. The only thing to watch out for is that we can't put
+ // a possibly trapping load in the predecessor if it is a critical edge.
+ for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
+ TerminatorInst *TI = PN.getIncomingBlock(Idx)->getTerminator();
+ Value *InVal = PN.getIncomingValue(Idx);
+
+ // If the value is produced by the terminator of the predecessor (an
+ // invoke) or it has side-effects, there is no valid place to put a load
+ // in the predecessor.
+ if (TI == InVal || TI->mayHaveSideEffects())
+ return false;
- assert(!Loads.empty());
+ // If the predecessor has a single successor, then the edge isn't
+ // critical.
+ if (TI->getNumSuccessors() == 1)
+ continue;
- Type *LoadTy = cast<PointerType>(PN.getType())->getElementType();
- IRBuilderTy PHIBuilder(&PN);
- PHINode *NewPN = PHIBuilder.CreatePHI(LoadTy, PN.getNumIncomingValues(),
- PN.getName() + ".sroa.speculated");
+ // If this pointer is always safe to load, or if we can prove that there
+ // is already a load in the block, then we can move the load to the pred
+ // block.
+ if (InVal->isDereferenceablePointer() ||
+ isSafeToLoadUnconditionally(InVal, TI, MaxAlign, TD))
+ continue;
- // Get the TBAA tag and alignment to use from one of the loads. It doesn't
- // matter which one we get and if any differ.
- LoadInst *SomeLoad = cast<LoadInst>(Loads.back());
- MDNode *TBAATag = SomeLoad->getMetadata(LLVMContext::MD_tbaa);
- unsigned Align = SomeLoad->getAlignment();
+ return false;
+ }
- // Rewrite all loads of the PN to use the new PHI.
- do {
- LoadInst *LI = Loads.pop_back_val();
- LI->replaceAllUsesWith(NewPN);
- Pass.DeadInsts.insert(LI);
- } while (!Loads.empty());
-
- // Inject loads into all of the pred blocks.
- for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
- BasicBlock *Pred = PN.getIncomingBlock(Idx);
- TerminatorInst *TI = Pred->getTerminator();
- Use *InUse = &PN.getOperandUse(PN.getOperandNumForIncomingValue(Idx));
- Value *InVal = PN.getIncomingValue(Idx);
- IRBuilderTy PredBuilder(TI);
-
- LoadInst *Load
- = PredBuilder.CreateLoad(InVal, (PN.getName() + ".sroa.speculate.load." +
- Pred->getName()));
- ++NumLoadsSpeculated;
- Load->setAlignment(Align);
- if (TBAATag)
- Load->setMetadata(LLVMContext::MD_tbaa, TBAATag);
- NewPN->addIncoming(Load, Pred);
-
- Instruction *Ptr = dyn_cast<Instruction>(InVal);
- if (!Ptr)
- // No uses to rewrite.
- continue;
+ return true;
+}
- // Try to lookup and rewrite any partition uses corresponding to this phi
- // input.
- AllocaPartitioning::iterator PI
- = P.findPartitionForPHIOrSelectOperand(InUse);
- if (PI == P.end())
- continue;
+static void speculatePHINodeLoads(PHINode &PN) {
+ DEBUG(dbgs() << " original: " << PN << "\n");
+
+ Type *LoadTy = cast<PointerType>(PN.getType())->getElementType();
+ IRBuilderTy PHIBuilder(&PN);
+ 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
+ // matter which one we get and if any differ.
+ LoadInst *SomeLoad = cast<LoadInst>(*PN.use_begin());
+ MDNode *TBAATag = SomeLoad->getMetadata(LLVMContext::MD_tbaa);
+ 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());
+ LI->replaceAllUsesWith(NewPN);
+ LI->eraseFromParent();
+ }
+
+ // Inject loads into all of the pred blocks.
+ for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
+ BasicBlock *Pred = PN.getIncomingBlock(Idx);
+ TerminatorInst *TI = Pred->getTerminator();
+ Value *InVal = PN.getIncomingValue(Idx);
+ IRBuilderTy PredBuilder(TI);
+
+ LoadInst *Load = PredBuilder.CreateLoad(
+ InVal, (PN.getName() + ".sroa.speculate.load." + Pred->getName()));
+ ++NumLoadsSpeculated;
+ Load->setAlignment(Align);
+ if (TBAATag)
+ Load->setMetadata(LLVMContext::MD_tbaa, TBAATag);
+ NewPN->addIncoming(Load, Pred);
+ }
+
+ DEBUG(dbgs() << " speculated to: " << *NewPN << "\n");
+ PN.eraseFromParent();
+}
- // Replace the Use in the PartitionUse for this operand with the Use
- // inside the load.
- AllocaPartitioning::use_iterator UI
- = P.findPartitionUseForPHIOrSelectOperand(InUse);
- assert(isa<PHINode>(*UI->getUse()->getUser()));
- UI->setUse(&Load->getOperandUse(Load->getPointerOperandIndex()));
- }
- DEBUG(dbgs() << " speculated to: " << *NewPN << "\n");
- }
-
- /// Select instructions that use an alloca and are subsequently loaded can be
- /// rewritten to load both input pointers and then select between the result,
- /// allowing the load of the alloca to be promoted.
- /// From this:
- /// %P2 = select i1 %cond, i32* %Alloca, i32* %Other
- /// %V = load i32* %P2
- /// to:
- /// %V1 = load i32* %Alloca -> will be mem2reg'd
- /// %V2 = load i32* %Other
- /// %V = select i1 %cond, i32 %V1, i32 %V2
- ///
- /// We can do this to a select if its only uses are loads and if the operand
- /// to the select can be loaded unconditionally.
- bool isSafeSelectToSpeculate(SelectInst &SI,
- SmallVectorImpl<LoadInst *> &Loads) {
- Value *TValue = SI.getTrueValue();
- Value *FValue = SI.getFalseValue();
- bool TDerefable = TValue->isDereferenceablePointer();
- bool FDerefable = FValue->isDereferenceablePointer();
-
- for (Value::use_iterator UI = SI.use_begin(), UE = SI.use_end();
- UI != UE; ++UI) {
- LoadInst *LI = dyn_cast<LoadInst>(*UI);
- if (LI == 0 || !LI->isSimple()) return false;
-
- // Both operands to the select need to be dereferencable, either
- // absolutely (e.g. allocas) or at this point because we can see other
- // accesses to it.
- if (!TDerefable && !isSafeToLoadUnconditionally(TValue, LI,
- LI->getAlignment(), &TD))
- return false;
- if (!FDerefable && !isSafeToLoadUnconditionally(FValue, LI,
- LI->getAlignment(), &TD))
- return false;
- Loads.push_back(LI);
- }
+/// Select instructions that use an alloca and are subsequently loaded can be
+/// rewritten to load both input pointers and then select between the result,
+/// allowing the load of the alloca to be promoted.
+/// From this:
+/// %P2 = select i1 %cond, i32* %Alloca, i32* %Other
+/// %V = load i32* %P2
+/// to:
+/// %V1 = load i32* %Alloca -> will be mem2reg'd
+/// %V2 = load i32* %Other
+/// %V = select i1 %cond, i32 %V1, i32 %V2
+///
+/// We can do this to a select if its only uses are loads and if the operand
+/// to the select can be loaded unconditionally.
+static bool isSafeSelectToSpeculate(SelectInst &SI, const DataLayout *TD = 0) {
+ Value *TValue = SI.getTrueValue();
+ Value *FValue = SI.getFalseValue();
+ bool TDerefable = TValue->isDereferenceablePointer();
+ bool FDerefable = FValue->isDereferenceablePointer();
+
+ for (Value::use_iterator UI = SI.use_begin(), UE = SI.use_end(); UI != UE;
+ ++UI) {
+ LoadInst *LI = dyn_cast<LoadInst>(*UI);
+ if (LI == 0 || !LI->isSimple())
+ return false;
- return true;
+ // Both operands to the select need to be dereferencable, either
+ // absolutely (e.g. allocas) or at this point because we can see other
+ // accesses to it.
+ if (!TDerefable &&
+ !isSafeToLoadUnconditionally(TValue, LI, LI->getAlignment(), TD))
+ return false;
+ if (!FDerefable &&
+ !isSafeToLoadUnconditionally(FValue, LI, LI->getAlignment(), TD))
+ return false;
}
- void visitSelectInst(SelectInst &SI) {
- DEBUG(dbgs() << " original: " << SI << "\n");
-
- // If the select isn't safe to speculate, just use simple logic to emit it.
- SmallVector<LoadInst *, 4> Loads;
- if (!isSafeSelectToSpeculate(SI, Loads))
- return;
+ return true;
+}
- IRBuilderTy IRB(&SI);
- Use *Ops[2] = { &SI.getOperandUse(1), &SI.getOperandUse(2) };
- AllocaPartitioning::iterator PIs[2];
- PartitionUse PUs[2];
- for (unsigned i = 0, e = 2; i != e; ++i) {
- PIs[i] = P.findPartitionForPHIOrSelectOperand(Ops[i]);
- if (PIs[i] != P.end()) {
- // If the pointer is within the partitioning, remove the select from
- // its uses. We'll add in the new loads below.
- AllocaPartitioning::use_iterator UI
- = P.findPartitionUseForPHIOrSelectOperand(Ops[i]);
- PUs[i] = *UI;
- // Clear out the use here so that the offsets into the use list remain
- // stable but this use is ignored when rewriting.
- UI->setUse(0);
- }
- }
+static void speculateSelectInstLoads(SelectInst &SI) {
+ DEBUG(dbgs() << " original: " << SI << "\n");
- Value *TV = SI.getTrueValue();
- Value *FV = SI.getFalseValue();
- // Replace the loads of the select with a select of two loads.
- while (!Loads.empty()) {
- LoadInst *LI = Loads.pop_back_val();
+ IRBuilderTy IRB(&SI);
+ Value *TV = SI.getTrueValue();
+ 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());
+ assert(LI->isSimple() && "We only speculate simple loads");
- IRB.SetInsertPoint(LI);
- LoadInst *TL =
+ IRB.SetInsertPoint(LI);
+ LoadInst *TL =
IRB.CreateLoad(TV, LI->getName() + ".sroa.speculate.load.true");
- LoadInst *FL =
+ LoadInst *FL =
IRB.CreateLoad(FV, LI->getName() + ".sroa.speculate.load.false");
- NumLoadsSpeculated += 2;
-
- // Transfer alignment and TBAA info if present.
- TL->setAlignment(LI->getAlignment());
- FL->setAlignment(LI->getAlignment());
- if (MDNode *Tag = LI->getMetadata(LLVMContext::MD_tbaa)) {
- TL->setMetadata(LLVMContext::MD_tbaa, Tag);
- FL->setMetadata(LLVMContext::MD_tbaa, Tag);
- }
+ NumLoadsSpeculated += 2;
- Value *V = IRB.CreateSelect(SI.getCondition(), TL, FL,
- LI->getName() + ".sroa.speculated");
+ // Transfer alignment and TBAA info if present.
+ TL->setAlignment(LI->getAlignment());
+ FL->setAlignment(LI->getAlignment());
+ if (MDNode *Tag = LI->getMetadata(LLVMContext::MD_tbaa)) {
+ TL->setMetadata(LLVMContext::MD_tbaa, Tag);
+ FL->setMetadata(LLVMContext::MD_tbaa, Tag);
+ }
- LoadInst *Loads[2] = { TL, FL };
- for (unsigned i = 0, e = 2; i != e; ++i) {
- if (PIs[i] != P.end()) {
- Use *LoadUse = &Loads[i]->getOperandUse(0);
- assert(PUs[i].getUse()->get() == LoadUse->get());
- PUs[i].setUse(LoadUse);
- P.use_push_back(PIs[i], PUs[i]);
- }
- }
+ Value *V = IRB.CreateSelect(SI.getCondition(), TL, FL,
+ LI->getName() + ".sroa.speculated");
- DEBUG(dbgs() << " speculated to: " << *V << "\n");
- LI->replaceAllUsesWith(V);
- Pass.DeadInsts.insert(LI);
- }
+ DEBUG(dbgs() << " speculated to: " << *V << "\n");
+ LI->replaceAllUsesWith(V);
+ LI->eraseFromParent();
}
-};
+ SI.eraseFromParent();
}
/// \brief Build a GEP out of a base pointer and indices.
return IRB.CreateBitCast(V, Ty);
}
+/// \brief Test whether the given partition use can be promoted to a vector.
+///
+/// This function is called to test each entry in a partioning which is slated
+/// for a single partition.
+static bool isVectorPromotionViableForPartitioning(
+ const DataLayout &TD, AllocaPartitioning &P,
+ uint64_t PartitionBeginOffset, uint64_t PartitionEndOffset, VectorType *Ty,
+ uint64_t ElementSize, AllocaPartitioning::const_iterator I) {
+ // First validate the partitioning offsets.
+ uint64_t BeginOffset =
+ std::max(I->beginOffset(), PartitionBeginOffset) - PartitionBeginOffset;
+ uint64_t BeginIndex = BeginOffset / ElementSize;
+ if (BeginIndex * ElementSize != BeginOffset ||
+ BeginIndex >= Ty->getNumElements())
+ return false;
+ uint64_t EndOffset =
+ std::min(I->endOffset(), PartitionEndOffset) - PartitionBeginOffset;
+ 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 *PartitionTy =
+ (NumElements == 1) ? Ty->getElementType()
+ : VectorType::get(Ty->getElementType(), NumElements);
+
+ Type *SplitIntTy =
+ Type::getIntNTy(Ty->getContext(), NumElements * ElementSize * 8);
+
+ Use *U = I->getUse();
+
+ if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
+ if (MI->isVolatile())
+ return false;
+ if (!I->isSplittable())
+ return false; // Skip any unsplittable intrinsics.
+ } else if (U->get()->getType()->getPointerElementType()->isStructTy()) {
+ // Disable vector promotion when there are loads or stores of an FCA.
+ return false;
+ } else if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
+ if (LI->isVolatile())
+ return false;
+ Type *LTy = LI->getType();
+ if (PartitionBeginOffset > I->beginOffset() ||
+ PartitionEndOffset < I->endOffset()) {
+ assert(LTy->isIntegerTy());
+ LTy = SplitIntTy;
+ }
+ if (!canConvertValue(TD, PartitionTy, LTy))
+ return false;
+ } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
+ if (SI->isVolatile())
+ return false;
+ Type *STy = SI->getValueOperand()->getType();
+ if (PartitionBeginOffset > I->beginOffset() ||
+ PartitionEndOffset < I->endOffset()) {
+ assert(STy->isIntegerTy());
+ STy = SplitIntTy;
+ }
+ if (!canConvertValue(TD, STy, PartitionTy))
+ return false;
+ }
+
+ return true;
+}
+
/// \brief Test whether the given alloca partition can be promoted to a vector.
///
/// This is a quick test to check whether we can rewrite a particular alloca
/// 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 &TD,
- Type *AllocaTy,
- AllocaPartitioning &P,
- uint64_t PartitionBeginOffset,
- uint64_t PartitionEndOffset,
- AllocaPartitioning::const_use_iterator I,
- AllocaPartitioning::const_use_iterator E) {
+static bool isVectorPromotionViable(
+ const DataLayout &TD, Type *AllocaTy, AllocaPartitioning &P,
+ uint64_t PartitionBeginOffset, uint64_t PartitionEndOffset,
+ AllocaPartitioning::const_iterator I, AllocaPartitioning::const_iterator E,
+ ArrayRef<AllocaPartitioning::iterator> SplitUses) {
VectorType *Ty = dyn_cast<VectorType>(AllocaTy);
if (!Ty)
return false;
"vector size not a multiple of element size?");
ElementSize /= 8;
- for (; I != E; ++I) {
- Use *U = I->getUse();
- if (!U)
- continue; // Skip dead use.
-
- uint64_t BeginOffset = I->BeginOffset - PartitionBeginOffset;
- uint64_t BeginIndex = BeginOffset / ElementSize;
- if (BeginIndex * ElementSize != BeginOffset ||
- BeginIndex >= Ty->getNumElements())
+ for (; I != E; ++I)
+ if (!isVectorPromotionViableForPartitioning(
+ TD, P, PartitionBeginOffset, PartitionEndOffset, Ty, ElementSize,
+ I))
return false;
- uint64_t EndOffset = I->EndOffset - PartitionBeginOffset;
- uint64_t EndIndex = EndOffset / ElementSize;
- if (EndIndex * ElementSize != EndOffset ||
- EndIndex > Ty->getNumElements())
+
+ for (ArrayRef<AllocaPartitioning::iterator>::const_iterator
+ SUI = SplitUses.begin(),
+ SUE = SplitUses.end();
+ SUI != SUE; ++SUI)
+ if (!isVectorPromotionViableForPartitioning(
+ TD, P, PartitionBeginOffset, PartitionEndOffset, Ty, ElementSize,
+ *SUI))
return false;
- assert(EndIndex > BeginIndex && "Empty vector!");
- uint64_t NumElements = EndIndex - BeginIndex;
- Type *PartitionTy
- = (NumElements == 1) ? Ty->getElementType()
- : VectorType::get(Ty->getElementType(), NumElements);
+ return true;
+}
- if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
- if (MI->isVolatile())
- return false;
- if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(U->getUser())) {
- const AllocaPartitioning::MemTransferOffsets &MTO
- = P.getMemTransferOffsets(*MTI);
- if (!MTO.IsSplittable)
- return false;
- }
- } else if (U->get()->getType()->getPointerElementType()->isStructTy()) {
- // Disable vector promotion when there are loads or stores of an FCA.
+/// \brief Test whether a partitioning slice of an alloca is a valid set of
+/// operations for integer widening.
+///
+/// This implements the necessary checking for the \c isIntegerWideningViable
+/// test below on a single partitioning slice of the alloca.
+static bool isIntegerWideningViableForPartitioning(
+ const DataLayout &TD, Type *AllocaTy, uint64_t AllocBeginOffset,
+ uint64_t Size, AllocaPartitioning &P, AllocaPartitioning::const_iterator I,
+ bool &WholeAllocaOp) {
+ uint64_t RelBegin = I->beginOffset() - AllocBeginOffset;
+ uint64_t RelEnd = I->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();
+
+ if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
+ if (LI->isVolatile())
return false;
- } else if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
- if (LI->isVolatile())
- return false;
- if (!canConvertValue(TD, PartitionTy, LI->getType()))
- return false;
- } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
- if (SI->isVolatile())
+ if (RelBegin == 0 && RelEnd == Size)
+ WholeAllocaOp = true;
+ if (IntegerType *ITy = dyn_cast<IntegerType>(LI->getType())) {
+ if (ITy->getBitWidth() < TD.getTypeStoreSizeInBits(ITy))
return false;
- if (!canConvertValue(TD, SI->getValueOperand()->getType(), PartitionTy))
+ } else if (RelBegin != 0 || RelEnd != Size ||
+ !canConvertValue(TD, AllocaTy, LI->getType())) {
+ // Non-integer loads need to be convertible from the alloca type so that
+ // they are promotable.
+ return false;
+ }
+ } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
+ Type *ValueTy = SI->getValueOperand()->getType();
+ if (SI->isVolatile())
+ return false;
+ if (RelBegin == 0 && RelEnd == Size)
+ WholeAllocaOp = true;
+ if (IntegerType *ITy = dyn_cast<IntegerType>(ValueTy)) {
+ if (ITy->getBitWidth() < TD.getTypeStoreSizeInBits(ITy))
return false;
- } else {
+ } else if (RelBegin != 0 || RelEnd != Size ||
+ !canConvertValue(TD, ValueTy, AllocaTy)) {
+ // Non-integer stores need to be convertible to the alloca type so that
+ // they are promotable.
return false;
}
+ } else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
+ if (MI->isVolatile() || !isa<Constant>(MI->getLength()))
+ return false;
+ if (!I->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 {
+ return false;
}
+
return true;
}
/// 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 &TD,
- Type *AllocaTy,
- uint64_t AllocBeginOffset,
- AllocaPartitioning &P,
- AllocaPartitioning::const_use_iterator I,
- AllocaPartitioning::const_use_iterator E) {
+static bool
+isIntegerWideningViable(const DataLayout &TD, Type *AllocaTy,
+ uint64_t AllocBeginOffset, AllocaPartitioning &P,
+ AllocaPartitioning::const_iterator I,
+ AllocaPartitioning::const_iterator E,
+ ArrayRef<AllocaPartitioning::iterator> SplitUses) {
uint64_t SizeInBits = TD.getTypeSizeInBits(AllocaTy);
// Don't create integer types larger than the maximum bitwidth.
if (SizeInBits > IntegerType::MAX_INT_BITS)
!canConvertValue(TD, IntTy, AllocaTy))
return false;
+ // If we have no actual uses of this partition, we're forming a fully
+ // splittable partition. Assume all the operations are easy to widen (they
+ // are if they're splittable), and just check that it's a good idea to form
+ // a single integer.
+ if (I == E)
+ return TD.isLegalInteger(SizeInBits);
+
uint64_t Size = TD.getTypeStoreSize(AllocaTy);
- // Check the uses to ensure the uses are (likely) promotable integer uses.
- // Also 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).
+ // 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).
bool WholeAllocaOp = false;
- for (; I != E; ++I) {
- Use *U = I->getUse();
- if (!U)
- continue; // Skip dead use.
-
- uint64_t RelBegin = I->BeginOffset - AllocBeginOffset;
- uint64_t RelEnd = I->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)
+ for (; I != E; ++I)
+ if (!isIntegerWideningViableForPartitioning(TD, AllocaTy, AllocBeginOffset,
+ Size, P, I, WholeAllocaOp))
return false;
- if (LoadInst *LI = dyn_cast<LoadInst>(U->getUser())) {
- if (LI->isVolatile())
- return false;
- if (RelBegin == 0 && RelEnd == Size)
- WholeAllocaOp = true;
- if (IntegerType *ITy = dyn_cast<IntegerType>(LI->getType())) {
- if (ITy->getBitWidth() < TD.getTypeStoreSizeInBits(ITy))
- return false;
- continue;
- }
- // Non-integer loads need to be convertible from the alloca type so that
- // they are promotable.
- if (RelBegin != 0 || RelEnd != Size ||
- !canConvertValue(TD, AllocaTy, LI->getType()))
- return false;
- } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
- Type *ValueTy = SI->getValueOperand()->getType();
- if (SI->isVolatile())
- return false;
- if (RelBegin == 0 && RelEnd == Size)
- WholeAllocaOp = true;
- if (IntegerType *ITy = dyn_cast<IntegerType>(ValueTy)) {
- if (ITy->getBitWidth() < TD.getTypeStoreSizeInBits(ITy))
- return false;
- continue;
- }
- // Non-integer stores need to be convertible to the alloca type so that
- // they are promotable.
- if (RelBegin != 0 || RelEnd != Size ||
- !canConvertValue(TD, ValueTy, AllocaTy))
- return false;
- } else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U->getUser())) {
- if (MI->isVolatile() || !isa<Constant>(MI->getLength()))
- return false;
- if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(U->getUser())) {
- const AllocaPartitioning::MemTransferOffsets &MTO
- = P.getMemTransferOffsets(*MTI);
- if (!MTO.IsSplittable)
- return false;
- }
- } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U->getUser())) {
- if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
- II->getIntrinsicID() != Intrinsic::lifetime_end)
- return false;
- } else {
+ for (ArrayRef<AllocaPartitioning::iterator>::const_iterator
+ SUI = SplitUses.begin(),
+ SUE = SplitUses.end();
+ SUI != SUE; ++SUI)
+ if (!isIntegerWideningViableForPartitioning(TD, AllocaTy, AllocBeginOffset,
+ Size, P, *SUI, WholeAllocaOp))
return false;
- }
- }
+
return WholeAllocaOp;
}
bool> {
// Befriend the base class so it can delegate to private visit methods.
friend class llvm::InstVisitor<AllocaPartitionRewriter, bool>;
+ typedef llvm::InstVisitor<AllocaPartitionRewriter, bool> Base;
const DataLayout &TD;
AllocaPartitioning &P;
// The offset of the partition user currently being rewritten.
uint64_t BeginOffset, EndOffset;
+ bool IsSplittable;
bool IsSplit;
Use *OldUse;
Instruction *OldPtr;
public:
AllocaPartitionRewriter(const DataLayout &TD, AllocaPartitioning &P,
- AllocaPartitioning::iterator PI,
SROA &Pass, AllocaInst &OldAI, AllocaInst &NewAI,
- uint64_t NewBeginOffset, uint64_t NewEndOffset)
- : TD(TD), P(P), Pass(Pass),
- OldAI(OldAI), NewAI(NewAI),
- NewAllocaBeginOffset(NewBeginOffset),
- NewAllocaEndOffset(NewEndOffset),
- NewAllocaTy(NewAI.getAllocatedType()),
- VecTy(), ElementTy(), ElementSize(), IntTy(),
- BeginOffset(), EndOffset(), IsSplit(), OldUse(), OldPtr(),
- IRB(NewAI.getContext(), ConstantFolder()) {
- }
-
- /// \brief Visit the users of the alloca partition and rewrite them.
- bool visitUsers(AllocaPartitioning::const_use_iterator I,
- AllocaPartitioning::const_use_iterator E) {
- if (isVectorPromotionViable(TD, NewAI.getAllocatedType(), P,
- NewAllocaBeginOffset, NewAllocaEndOffset,
- I, E)) {
- ++NumVectorized;
- VecTy = cast<VectorType>(NewAI.getAllocatedType());
- ElementTy = VecTy->getElementType();
- assert((TD.getTypeSizeInBits(VecTy->getScalarType()) % 8) == 0 &&
+ uint64_t NewBeginOffset, uint64_t NewEndOffset,
+ bool IsVectorPromotable = false,
+ bool IsIntegerPromotable = false)
+ : TD(TD), P(P), Pass(Pass), OldAI(OldAI), NewAI(NewAI),
+ NewAllocaBeginOffset(NewBeginOffset), NewAllocaEndOffset(NewEndOffset),
+ NewAllocaTy(NewAI.getAllocatedType()),
+ VecTy(IsVectorPromotable ? cast<VectorType>(NewAllocaTy) : 0),
+ ElementTy(VecTy ? VecTy->getElementType() : 0),
+ ElementSize(VecTy ? TD.getTypeSizeInBits(ElementTy) / 8 : 0),
+ IntTy(IsIntegerPromotable
+ ? Type::getIntNTy(
+ NewAI.getContext(),
+ TD.getTypeSizeInBits(NewAI.getAllocatedType()))
+ : 0),
+ BeginOffset(), EndOffset(), IsSplittable(), IsSplit(), OldUse(),
+ OldPtr(), IRB(NewAI.getContext(), ConstantFolder()) {
+ if (VecTy) {
+ assert((TD.getTypeSizeInBits(ElementTy) % 8) == 0 &&
"Only multiple-of-8 sized vector elements are viable");
- ElementSize = TD.getTypeSizeInBits(VecTy->getScalarType()) / 8;
- } else if (isIntegerWideningViable(TD, NewAI.getAllocatedType(),
- NewAllocaBeginOffset, P, I, E)) {
- IntTy = Type::getIntNTy(NewAI.getContext(),
- TD.getTypeSizeInBits(NewAI.getAllocatedType()));
+ ++NumVectorized;
}
+ assert((!IsVectorPromotable && !IsIntegerPromotable) ||
+ IsVectorPromotable != IsIntegerPromotable);
+ }
+
+ bool visit(AllocaPartitioning::const_iterator I) {
bool CanSROA = true;
- for (; I != E; ++I) {
- if (!I->getUse())
- continue; // Skip dead uses.
- BeginOffset = I->BeginOffset;
- EndOffset = I->EndOffset;
- IsSplit = I->isSplit();
- OldUse = I->getUse();
- OldPtr = cast<Instruction>(OldUse->get());
-
- Instruction *OldUserI = cast<Instruction>(OldUse->getUser());
- IRB.SetInsertPoint(OldUserI);
- IRB.SetCurrentDebugLocation(OldUserI->getDebugLoc());
- IRB.SetNamePrefix(Twine(NewAI.getName()) + "." + Twine(BeginOffset) +
- ".");
-
- CanSROA &= visit(cast<Instruction>(OldUse->getUser()));
- }
- if (VecTy) {
- assert(CanSROA);
- VecTy = 0;
- ElementTy = 0;
- ElementSize = 0;
- }
- if (IntTy) {
+ BeginOffset = I->beginOffset();
+ EndOffset = I->endOffset();
+ IsSplittable = I->isSplittable();
+ IsSplit =
+ BeginOffset < NewAllocaBeginOffset || EndOffset > NewAllocaEndOffset;
+
+ OldUse = I->getUse();
+ OldPtr = cast<Instruction>(OldUse->get());
+
+ Instruction *OldUserI = cast<Instruction>(OldUse->getUser());
+ IRB.SetInsertPoint(OldUserI);
+ IRB.SetCurrentDebugLocation(OldUserI->getDebugLoc());
+ IRB.SetNamePrefix(Twine(NewAI.getName()) + "." + Twine(BeginOffset) + ".");
+
+ CanSROA &= visit(cast<Instruction>(OldUse->getUser()));
+ if (VecTy || IntTy)
assert(CanSROA);
- IntTy = 0;
- }
return CanSROA;
}
private:
+ // Make sure the other visit overloads are visible.
+ using Base::visit;
+
// Every instruction which can end up as a user must have a rewrite rule.
bool visitInstruction(Instruction &I) {
DEBUG(dbgs() << " !!!! Cannot rewrite: " << I << "\n");
llvm_unreachable("No rewrite rule for this instruction!");
}
- Value *getAdjustedAllocaPtr(IRBuilderTy &IRB, Type *PointerTy) {
- assert(BeginOffset >= NewAllocaBeginOffset);
- APInt Offset(TD.getPointerSizeInBits(), BeginOffset - NewAllocaBeginOffset);
- return getAdjustedPtr(IRB, TD, &NewAI, Offset, PointerTy);
+ Value *getAdjustedAllocaPtr(IRBuilderTy &IRB, uint64_t Offset,
+ Type *PointerTy) {
+ assert(Offset >= NewAllocaBeginOffset);
+ return getAdjustedPtr(IRB, TD, &NewAI, APInt(TD.getPointerSizeInBits(),
+ Offset - NewAllocaBeginOffset),
+ PointerTy);
}
/// \brief Compute suitable alignment to access an offset into the new alloca.
return MinAlign(NewAIAlign, Offset);
}
- /// \brief Compute suitable alignment to access this partition of the new
- /// alloca.
- unsigned getPartitionAlign() {
- return getOffsetAlign(BeginOffset - NewAllocaBeginOffset);
- }
-
/// \brief Compute suitable alignment to access a type at an offset of the
/// new alloca.
///
return Align == TD.getABITypeAlignment(Ty) ? 0 : Align;
}
- /// \brief Compute suitable alignment to access a type at the beginning of
- /// this partition of the new alloca.
- ///
- /// See \c getOffsetTypeAlign for details; this routine delegates to it.
- unsigned getPartitionTypeAlign(Type *Ty) {
- return getOffsetTypeAlign(Ty, BeginOffset - NewAllocaBeginOffset);
- }
-
unsigned getIndex(uint64_t Offset) {
assert(VecTy && "Can only call getIndex when rewriting a vector");
uint64_t RelOffset = Offset - NewAllocaBeginOffset;
Pass.DeadInsts.insert(I);
}
- Value *rewriteVectorizedLoadInst() {
- unsigned BeginIndex = getIndex(BeginOffset);
- unsigned EndIndex = getIndex(EndOffset);
+ Value *rewriteVectorizedLoadInst(uint64_t NewBeginOffset,
+ uint64_t NewEndOffset) {
+ unsigned BeginIndex = getIndex(NewBeginOffset);
+ unsigned EndIndex = getIndex(NewEndOffset);
assert(EndIndex > BeginIndex && "Empty vector!");
Value *V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
return extractVector(IRB, V, BeginIndex, EndIndex, "vec");
}
- Value *rewriteIntegerLoad(LoadInst &LI) {
+ Value *rewriteIntegerLoad(LoadInst &LI, uint64_t NewBeginOffset,
+ uint64_t NewEndOffset) {
assert(IntTy && "We cannot insert an integer to the alloca");
assert(!LI.isVolatile());
Value *V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
"load");
V = convertValue(TD, IRB, V, IntTy);
- assert(BeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
- uint64_t Offset = BeginOffset - NewAllocaBeginOffset;
- if (Offset > 0 || EndOffset < NewAllocaEndOffset)
+ assert(NewBeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
+ uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
+ if (Offset > 0 || NewEndOffset < NewAllocaEndOffset)
V = extractInteger(TD, IRB, V, cast<IntegerType>(LI.getType()), Offset,
"extract");
return V;
Value *OldOp = LI.getOperand(0);
assert(OldOp == OldPtr);
- uint64_t Size = EndOffset - BeginOffset;
+ // 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)
: LI.getType();
bool IsPtrAdjusted = false;
Value *V;
if (VecTy) {
- V = rewriteVectorizedLoadInst();
+ V = rewriteVectorizedLoadInst(NewBeginOffset, NewEndOffset);
} else if (IntTy && LI.getType()->isIntegerTy()) {
- V = rewriteIntegerLoad(LI);
- } else if (BeginOffset == NewAllocaBeginOffset &&
+ V = rewriteIntegerLoad(LI, NewBeginOffset, NewEndOffset);
+ } else if (NewBeginOffset == NewAllocaBeginOffset &&
canConvertValue(TD, NewAllocaTy, LI.getType())) {
V = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
LI.isVolatile(), "load");
} else {
Type *LTy = TargetTy->getPointerTo();
- V = IRB.CreateAlignedLoad(getAdjustedAllocaPtr(IRB, LTy),
- getPartitionTypeAlign(TargetTy),
- LI.isVolatile(), "load");
+ V = IRB.CreateAlignedLoad(
+ getAdjustedAllocaPtr(IRB, NewBeginOffset, LTy),
+ getOffsetTypeAlign(TargetTy, NewBeginOffset - NewAllocaBeginOffset),
+ LI.isVolatile(), "load");
IsPtrAdjusted = true;
}
V = convertValue(TD, IRB, V, TargetTy);
// LI only used for this computation.
Value *Placeholder
= new LoadInst(UndefValue::get(LI.getType()->getPointerTo()));
- V = insertInteger(TD, IRB, Placeholder, V, BeginOffset,
+ V = insertInteger(TD, IRB, Placeholder, V, NewBeginOffset,
"insert");
LI.replaceAllUsesWith(V);
Placeholder->replaceAllUsesWith(&LI);
return !LI.isVolatile() && !IsPtrAdjusted;
}
- bool rewriteVectorizedStoreInst(Value *V,
- StoreInst &SI, Value *OldOp) {
+ bool rewriteVectorizedStoreInst(Value *V, StoreInst &SI, Value *OldOp,
+ uint64_t NewBeginOffset,
+ uint64_t NewEndOffset) {
if (V->getType() != VecTy) {
- unsigned BeginIndex = getIndex(BeginOffset);
- unsigned EndIndex = getIndex(EndOffset);
+ unsigned BeginIndex = getIndex(NewBeginOffset);
+ unsigned EndIndex = getIndex(NewEndOffset);
assert(EndIndex > BeginIndex && "Empty vector!");
unsigned NumElements = EndIndex - BeginIndex;
assert(NumElements <= VecTy->getNumElements() && "Too many elements!");
return true;
}
- bool rewriteIntegerStore(Value *V, StoreInst &SI) {
+ bool rewriteIntegerStore(Value *V, StoreInst &SI,
+ uint64_t NewBeginOffset, uint64_t NewEndOffset) {
assert(IntTy && "We cannot extract an integer from the alloca");
assert(!SI.isVolatile());
if (TD.getTypeSizeInBits(V->getType()) != IntTy->getBitWidth()) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(V->stripInBoundsOffsets()))
Pass.PostPromotionWorklist.insert(AI);
- uint64_t Size = EndOffset - BeginOffset;
+ // 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 < TD.getTypeStoreSize(V->getType())) {
assert(!SI.isVolatile());
- assert(IsSplit && "A seemingly split store isn't splittable");
assert(V->getType()->isIntegerTy() &&
"Only integer type loads and stores are split");
assert(V->getType()->getIntegerBitWidth() ==
TD.getTypeStoreSizeInBits(V->getType()) &&
"Non-byte-multiple bit width");
IntegerType *NarrowTy = Type::getIntNTy(SI.getContext(), Size * 8);
- V = extractInteger(TD, IRB, V, NarrowTy, BeginOffset,
+ V = extractInteger(TD, IRB, V, NarrowTy, NewBeginOffset,
"extract");
}
if (VecTy)
- return rewriteVectorizedStoreInst(V, SI, OldOp);
+ return rewriteVectorizedStoreInst(V, SI, OldOp, NewBeginOffset,
+ NewEndOffset);
if (IntTy && V->getType()->isIntegerTy())
- return rewriteIntegerStore(V, SI);
+ return rewriteIntegerStore(V, SI, NewBeginOffset, NewEndOffset);
StoreInst *NewSI;
- if (BeginOffset == NewAllocaBeginOffset &&
- EndOffset == NewAllocaEndOffset &&
+ if (NewBeginOffset == NewAllocaBeginOffset &&
+ NewEndOffset == NewAllocaEndOffset &&
canConvertValue(TD, V->getType(), NewAllocaTy)) {
V = convertValue(TD, IRB, V, NewAllocaTy);
NewSI = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlignment(),
SI.isVolatile());
} else {
- Value *NewPtr = getAdjustedAllocaPtr(IRB, V->getType()->getPointerTo());
- NewSI = IRB.CreateAlignedStore(V, NewPtr,
- getPartitionTypeAlign(V->getType()),
- SI.isVolatile());
+ Value *NewPtr = getAdjustedAllocaPtr(IRB, NewBeginOffset,
+ V->getType()->getPointerTo());
+ NewSI = IRB.CreateAlignedStore(
+ V, NewPtr, getOffsetTypeAlign(
+ V->getType(), NewBeginOffset - NewAllocaBeginOffset),
+ SI.isVolatile());
}
(void)NewSI;
Pass.DeadInsts.insert(&SI);
// If the memset has a variable size, it cannot be split, just adjust the
// pointer to the new alloca.
if (!isa<Constant>(II.getLength())) {
- II.setDest(getAdjustedAllocaPtr(IRB, II.getRawDest()->getType()));
+ assert(!IsSplit);
+ assert(BeginOffset >= NewAllocaBeginOffset);
+ II.setDest(
+ getAdjustedAllocaPtr(IRB, BeginOffset, II.getRawDest()->getType()));
Type *CstTy = II.getAlignmentCst()->getType();
- II.setAlignment(ConstantInt::get(CstTy, getPartitionAlign()));
+ II.setAlignment(ConstantInt::get(CstTy, getOffsetAlign(BeginOffset)));
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 PartitionOffset = 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 ||
!AllocaTy->isSingleValueType() ||
!TD.isLegalInteger(TD.getTypeSizeInBits(ScalarTy)) ||
TD.getTypeSizeInBits(ScalarTy)%8 != 0)) {
Type *SizeTy = II.getLength()->getType();
- Constant *Size = ConstantInt::get(SizeTy, EndOffset - BeginOffset);
- CallInst *New
- = IRB.CreateMemSet(getAdjustedAllocaPtr(IRB,
- II.getRawDest()->getType()),
- II.getValue(), Size, getPartitionAlign(),
- II.isVolatile());
+ Constant *Size = ConstantInt::get(SizeTy, NewEndOffset - NewBeginOffset);
+ CallInst *New = IRB.CreateMemSet(
+ getAdjustedAllocaPtr(IRB, NewBeginOffset, II.getRawDest()->getType()),
+ II.getValue(), Size, getOffsetAlign(PartitionOffset),
+ II.isVolatile());
(void)New;
DEBUG(dbgs() << " to: " << *New << "\n");
return false;
// If this is a memset of a vectorized alloca, insert it.
assert(ElementTy == ScalarTy);
- unsigned BeginIndex = getIndex(BeginOffset);
- unsigned EndIndex = getIndex(EndOffset);
+ unsigned BeginIndex = getIndex(NewBeginOffset);
+ unsigned EndIndex = getIndex(NewEndOffset);
assert(EndIndex > BeginIndex && "Empty vector!");
unsigned NumElements = EndIndex - BeginIndex;
assert(NumElements <= VecTy->getNumElements() && "Too many elements!");
// set integer.
assert(!II.isVolatile());
- uint64_t Size = EndOffset - BeginOffset;
+ uint64_t Size = NewEndOffset - NewBeginOffset;
V = getIntegerSplat(II.getValue(), Size);
if (IntTy && (BeginOffset != NewAllocaBeginOffset ||
Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
"oldload");
Old = convertValue(TD, IRB, Old, IntTy);
- assert(BeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
- uint64_t Offset = BeginOffset - NewAllocaBeginOffset;
+ uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
V = insertInteger(TD, IRB, Old, V, Offset, "insert");
} else {
assert(V->getType() == IntTy &&
V = convertValue(TD, IRB, V, AllocaTy);
} else {
// Established these invariants above.
- assert(BeginOffset == NewAllocaBeginOffset);
- assert(EndOffset == NewAllocaEndOffset);
+ assert(NewBeginOffset == NewAllocaBeginOffset);
+ assert(NewEndOffset == NewAllocaEndOffset);
V = getIntegerSplat(II.getValue(), TD.getTypeSizeInBits(ScalarTy) / 8);
if (VectorType *AllocaVecTy = dyn_cast<VectorType>(AllocaTy))
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);
+
assert(II.getRawSource() == OldPtr || II.getRawDest() == OldPtr);
bool IsDest = II.getRawDest() == OldPtr;
- const AllocaPartitioning::MemTransferOffsets &MTO
- = P.getMemTransferOffsets(II);
-
// Compute the relative offset within the transfer.
unsigned IntPtrWidth = TD.getPointerSizeInBits();
- APInt RelOffset(IntPtrWidth, BeginOffset - (IsDest ? MTO.DestBegin
- : MTO.SourceBegin));
+ APInt RelOffset(IntPtrWidth, NewBeginOffset - BeginOffset);
unsigned Align = II.getAlignment();
+ uint64_t PartitionOffset = NewBeginOffset - NewAllocaBeginOffset;
if (Align > 1)
- Align = MinAlign(RelOffset.zextOrTrunc(64).getZExtValue(),
- MinAlign(II.getAlignment(), getPartitionAlign()));
+ Align = MinAlign(
+ RelOffset.zextOrTrunc(64).getZExtValue(),
+ MinAlign(II.getAlignment(), getOffsetAlign(PartitionOffset)));
// For unsplit intrinsics, we simply modify the source and destination
// pointers in place. This isn't just an optimization, it is a matter of
// a variable length. We may also be dealing with memmove instead of
// memcpy, and so simply updating the pointers is the necessary for us to
// update both source and dest of a single call.
- if (!MTO.IsSplittable) {
+ if (!IsSplittable) {
Value *OldOp = IsDest ? II.getRawDest() : II.getRawSource();
if (IsDest)
- II.setDest(getAdjustedAllocaPtr(IRB, II.getRawDest()->getType()));
+ II.setDest(
+ getAdjustedAllocaPtr(IRB, BeginOffset, II.getRawDest()->getType()));
else
- II.setSource(getAdjustedAllocaPtr(IRB, II.getRawSource()->getType()));
+ II.setSource(getAdjustedAllocaPtr(IRB, BeginOffset,
+ II.getRawSource()->getType()));
Type *CstTy = II.getAlignmentCst()->getType();
II.setAlignment(ConstantInt::get(CstTy, Align));
// 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 ||
+ = !VecTy && !IntTy && (BeginOffset > NewAllocaBeginOffset ||
+ EndOffset < NewAllocaEndOffset ||
!NewAI.getAllocatedType()->isSingleValueType());
// If we're just going to emit a memcpy, the alloca hasn't changed, and the
// size hasn't been shrunk based on analysis of the viable range, this is
// a no-op.
if (EmitMemCpy && &OldAI == &NewAI) {
- uint64_t OrigBegin = IsDest ? MTO.DestBegin : MTO.SourceBegin;
- uint64_t OrigEnd = IsDest ? MTO.DestEnd : MTO.SourceEnd;
// Ensure the start lines up.
- assert(BeginOffset == OrigBegin);
- (void)OrigBegin;
+ assert(NewBeginOffset == BeginOffset);
// Rewrite the size as needed.
- if (EndOffset != OrigEnd)
+ if (NewEndOffset != EndOffset)
II.setLength(ConstantInt::get(II.getLength()->getType(),
- EndOffset - BeginOffset));
+ NewEndOffset - NewBeginOffset));
return false;
}
// Record this instruction for deletion.
// a single, simple GEP in most cases.
OtherPtr = getAdjustedPtr(IRB, TD, OtherPtr, RelOffset, OtherPtrTy);
- Value *OurPtr
- = getAdjustedAllocaPtr(IRB, IsDest ? II.getRawDest()->getType()
- : II.getRawSource()->getType());
+ Value *OurPtr = getAdjustedAllocaPtr(
+ IRB, NewBeginOffset,
+ IsDest ? II.getRawDest()->getType() : II.getRawSource()->getType());
Type *SizeTy = II.getLength()->getType();
- Constant *Size = ConstantInt::get(SizeTy, EndOffset - BeginOffset);
+ Constant *Size = ConstantInt::get(SizeTy, NewEndOffset - NewBeginOffset);
CallInst *New = IRB.CreateMemCpy(IsDest ? OurPtr : OtherPtr,
IsDest ? OtherPtr : OurPtr,
if (!Align)
Align = 1;
- bool IsWholeAlloca = BeginOffset == NewAllocaBeginOffset &&
- EndOffset == NewAllocaEndOffset;
- uint64_t Size = EndOffset - BeginOffset;
- unsigned BeginIndex = VecTy ? getIndex(BeginOffset) : 0;
- unsigned EndIndex = VecTy ? getIndex(EndOffset) : 0;
+ 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;
Src = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
"load");
Src = convertValue(TD, IRB, Src, IntTy);
- assert(BeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
- uint64_t Offset = BeginOffset - NewAllocaBeginOffset;
+ uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
Src = extractInteger(TD, IRB, Src, SubIntTy, Offset, "extract");
} else {
Src = IRB.CreateAlignedLoad(SrcPtr, Align, II.isVolatile(),
Value *Old = IRB.CreateAlignedLoad(&NewAI, NewAI.getAlignment(),
"oldload");
Old = convertValue(TD, IRB, Old, IntTy);
- assert(BeginOffset >= NewAllocaBeginOffset && "Out of bounds offset");
- uint64_t Offset = BeginOffset - NewAllocaBeginOffset;
+ uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
Src = insertInteger(TD, IRB, Old, Src, Offset, "insert");
Src = convertValue(TD, IRB, Src, NewAllocaTy);
}
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()),
- EndOffset - BeginOffset);
- Value *Ptr = getAdjustedAllocaPtr(IRB, II.getArgOperand(1)->getType());
+ NewEndOffset - NewBeginOffset);
+ Value *Ptr =
+ getAdjustedAllocaPtr(IRB, NewBeginOffset, II.getArgOperand(1)->getType());
Value *New;
if (II.getIntrinsicID() == Intrinsic::lifetime_start)
New = IRB.CreateLifetimeStart(Ptr, Size);
bool visitPHINode(PHINode &PN) {
DEBUG(dbgs() << " original: " << PN << "\n");
+ assert(BeginOffset >= NewAllocaBeginOffset && "PHIs are unsplittable");
+ assert(EndOffset <= NewAllocaEndOffset && "PHIs are unsplittable");
// We would like to compute a new pointer in only one place, but have it be
// as local as possible to the PHI. To do that, we re-use the location of
PtrBuilder.SetNamePrefix(Twine(NewAI.getName()) + "." + Twine(BeginOffset) +
".");
- Value *NewPtr = getAdjustedAllocaPtr(PtrBuilder, OldPtr->getType());
+ Value *NewPtr =
+ getAdjustedAllocaPtr(PtrBuilder, BeginOffset, OldPtr->getType());
// Replace the operands which were using the old pointer.
std::replace(PN.op_begin(), PN.op_end(), cast<Value>(OldPtr), NewPtr);
DEBUG(dbgs() << " to: " << PN << "\n");
deleteIfTriviallyDead(OldPtr);
- return false;
+
+ // Check whether we can speculate this PHI node, and if so remember that
+ // fact and return that this alloca remains viable for promotion to an SSA
+ // value.
+ if (isSafePHIToSpeculate(PN, &TD)) {
+ Pass.SpeculatablePHIs.insert(&PN);
+ return true;
+ }
+
+ return false; // PHIs can't be promoted on their own.
}
bool visitSelectInst(SelectInst &SI) {
DEBUG(dbgs() << " original: " << SI << "\n");
assert((SI.getTrueValue() == OldPtr || SI.getFalseValue() == OldPtr) &&
"Pointer isn't an operand!");
+ assert(BeginOffset >= NewAllocaBeginOffset && "Selects are unsplittable");
+ assert(EndOffset <= NewAllocaEndOffset && "Selects are unsplittable");
- Value *NewPtr = getAdjustedAllocaPtr(IRB, OldPtr->getType());
+ Value *NewPtr = getAdjustedAllocaPtr(IRB, BeginOffset, OldPtr->getType());
// Replace the operands which were using the old pointer.
if (SI.getOperand(1) == OldPtr)
SI.setOperand(1, NewPtr);
DEBUG(dbgs() << " to: " << SI << "\n");
deleteIfTriviallyDead(OldPtr);
- return false;
+
+ // Check whether we can speculate this select instruction, and if so
+ // remember that fact and return that this alloca remains viable for
+ // promotion to an SSA value.
+ if (isSafeSelectToSpeculate(SI, &TD)) {
+ Pass.SpeculatableSelects.insert(&SI);
+ return true;
+ }
+
+ return false; // Selects can't be promoted on their own.
}
};
/// appropriate new offsets. It also evaluates how successful the rewrite was
/// at enabling promotion and if it was successful queues the alloca to be
/// promoted.
-bool SROA::rewriteAllocaPartition(AllocaInst &AI,
- AllocaPartitioning &P,
- AllocaPartitioning::iterator PI) {
- uint64_t AllocaSize = PI->EndOffset - PI->BeginOffset;
- bool IsLive = false;
- for (AllocaPartitioning::use_iterator UI = P.use_begin(PI),
- UE = P.use_end(PI);
- UI != UE && !IsLive; ++UI)
- if (UI->getUse())
- IsLive = true;
- if (!IsLive)
- return false; // No live uses left of this partition.
-
- DEBUG(dbgs() << "Speculating PHIs and selects in partition "
- << "[" << PI->BeginOffset << "," << PI->EndOffset << ")\n");
-
- PHIOrSelectSpeculator Speculator(*TD, P, *this);
- DEBUG(dbgs() << " speculating ");
- DEBUG(P.print(dbgs(), PI, ""));
- Speculator.visitUsers(PI);
+bool SROA::rewritePartitions(AllocaInst &AI, AllocaPartitioning &P,
+ AllocaPartitioning::iterator B,
+ AllocaPartitioning::iterator E,
+ int64_t BeginOffset, int64_t EndOffset,
+ ArrayRef<AllocaPartitioning::iterator> SplitUses) {
+ assert(BeginOffset < EndOffset);
+ uint64_t PartitionSize = EndOffset - BeginOffset;
// Try to compute a friendly type for this partition of the alloca. This
// won't always succeed, in which case we fall back to a legal integer type
// or an i8 array of an appropriate size.
- Type *AllocaTy = 0;
- if (Type *PartitionTy = P.getCommonType(PI))
- if (TD->getTypeAllocSize(PartitionTy) >= AllocaSize)
- AllocaTy = PartitionTy;
- if (!AllocaTy)
- if (Type *PartitionTy = getTypePartition(*TD, AI.getAllocatedType(),
- PI->BeginOffset, AllocaSize))
- AllocaTy = PartitionTy;
- if ((!AllocaTy ||
- (AllocaTy->isArrayTy() &&
- AllocaTy->getArrayElementType()->isIntegerTy())) &&
- TD->isLegalInteger(AllocaSize * 8))
- AllocaTy = Type::getIntNTy(*C, AllocaSize * 8);
- if (!AllocaTy)
- AllocaTy = ArrayType::get(Type::getInt8Ty(*C), AllocaSize);
- assert(TD->getTypeAllocSize(AllocaTy) >= AllocaSize);
+ Type *PartitionTy = 0;
+ if (Type *CommonUseTy = findCommonType(B, E, EndOffset))
+ if (TD->getTypeAllocSize(CommonUseTy) >= PartitionSize)
+ PartitionTy = CommonUseTy;
+ if (!PartitionTy)
+ if (Type *TypePartitionTy = getTypePartition(*TD, AI.getAllocatedType(),
+ BeginOffset, PartitionSize))
+ PartitionTy = TypePartitionTy;
+ if ((!PartitionTy || (PartitionTy->isArrayTy() &&
+ PartitionTy->getArrayElementType()->isIntegerTy())) &&
+ TD->isLegalInteger(PartitionSize * 8))
+ PartitionTy = Type::getIntNTy(*C, PartitionSize * 8);
+ if (!PartitionTy)
+ PartitionTy = ArrayType::get(Type::getInt8Ty(*C), PartitionSize);
+ assert(TD->getTypeAllocSize(PartitionTy) >= PartitionSize);
+
+ bool IsVectorPromotable = isVectorPromotionViable(
+ *TD, PartitionTy, P, BeginOffset, EndOffset, B, E, SplitUses);
+
+ bool IsIntegerPromotable =
+ !IsVectorPromotable &&
+ isIntegerWideningViable(*TD, PartitionTy, BeginOffset, P, B, E,
+ SplitUses);
// Check for the case where we're going to rewrite to a new alloca of the
// exact same type as the original, and with the same access offsets. In that
// case, re-use the existing alloca, but still run through the rewriter to
// perform phi and select speculation.
AllocaInst *NewAI;
- if (AllocaTy == AI.getAllocatedType()) {
- assert(PI->BeginOffset == 0 &&
+ if (PartitionTy == AI.getAllocatedType()) {
+ assert(BeginOffset == 0 &&
"Non-zero begin offset but same alloca type");
- assert(PI == P.begin() && "Begin offset is zero on later partition");
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.
} else {
unsigned Alignment = AI.getAlignment();
if (!Alignment) {
// type.
Alignment = TD->getABITypeAlignment(AI.getAllocatedType());
}
- Alignment = MinAlign(Alignment, PI->BeginOffset);
+ Alignment = MinAlign(Alignment, BeginOffset);
// If we will get at least this much alignment from the type alone, leave
// the alloca's alignment unconstrained.
- if (Alignment <= TD->getABITypeAlignment(AllocaTy))
+ if (Alignment <= TD->getABITypeAlignment(PartitionTy))
Alignment = 0;
- NewAI = new AllocaInst(AllocaTy, 0, Alignment,
- AI.getName() + ".sroa." + Twine(PI - P.begin()),
- &AI);
+ NewAI = new AllocaInst(PartitionTy, 0, Alignment,
+ AI.getName() + ".sroa." + Twine(B - P.begin()), &AI);
++NumNewAllocas;
}
DEBUG(dbgs() << "Rewriting alloca partition "
- << "[" << PI->BeginOffset << "," << PI->EndOffset << ") to: "
- << *NewAI << "\n");
+ << "[" << BeginOffset << "," << EndOffset << ") to: " << *NewAI
+ << "\n");
- // Track the high watermark of the post-promotion worklist. We will reset it
- // to this point if the alloca is not in fact scheduled for promotion.
+ // Track the high watermark on several worklists that are only relevant for
+ // promoted allocas. We will reset it to this point if the alloca is not in
+ // fact scheduled for promotion.
unsigned PPWOldSize = PostPromotionWorklist.size();
-
- AllocaPartitionRewriter Rewriter(*TD, P, PI, *this, AI, *NewAI,
- PI->BeginOffset, PI->EndOffset);
- DEBUG(dbgs() << " rewriting ");
- DEBUG(P.print(dbgs(), PI, ""));
- bool Promotable = Rewriter.visitUsers(P.use_begin(PI), P.use_end(PI));
- if (Promotable) {
+ unsigned SPOldSize = SpeculatablePHIs.size();
+ unsigned SSOldSize = SpeculatableSelects.size();
+
+ AllocaPartitionRewriter Rewriter(*TD, P, *this, AI, *NewAI, BeginOffset,
+ EndOffset, IsVectorPromotable,
+ IsIntegerPromotable);
+ bool Promotable = true;
+ for (ArrayRef<AllocaPartitioning::iterator>::const_iterator
+ SUI = SplitUses.begin(),
+ SUE = SplitUses.end();
+ SUI != SUE; ++SUI) {
+ DEBUG(dbgs() << " rewriting split ");
+ DEBUG(P.printPartition(dbgs(), *SUI, ""));
+ Promotable &= Rewriter.visit(*SUI);
+ }
+ for (AllocaPartitioning::iterator I = B; I != E; ++I) {
+ DEBUG(dbgs() << " rewriting ");
+ DEBUG(P.printPartition(dbgs(), I, ""));
+ Promotable &= Rewriter.visit(I);
+ }
+
+ if (Promotable && (SpeculatablePHIs.size() > SPOldSize ||
+ SpeculatableSelects.size() > SSOldSize)) {
+ // If we have a promotable alloca except for some unspeculated loads below
+ // PHIs or Selects, iterate once. We will speculate the loads and on the
+ // next iteration rewrite them into a promotable form.
+ Worklist.insert(NewAI);
+ } else if (Promotable) {
DEBUG(dbgs() << " and queuing for promotion\n");
PromotableAllocas.push_back(NewAI);
} else if (NewAI != &AI) {
// If we can't promote the alloca, iterate on it to check for new
// refinements exposed by splitting the current alloca. Don't iterate on an
// alloca which didn't actually change and didn't get promoted.
+ // FIXME: We should actually track whether the rewriter changed anything.
Worklist.insert(NewAI);
}
// Drop any post-promotion work items if promotion didn't happen.
- if (!Promotable)
+ if (!Promotable) {
while (PostPromotionWorklist.size() > PPWOldSize)
PostPromotionWorklist.pop_back();
+ while (SpeculatablePHIs.size() > SPOldSize)
+ SpeculatablePHIs.pop_back();
+ while (SpeculatableSelects.size() > SSOldSize)
+ SpeculatableSelects.pop_back();
+ }
return true;
}
+namespace {
+ struct IsPartitionEndLessOrEqualTo {
+ uint64_t UpperBound;
+
+ IsPartitionEndLessOrEqualTo(uint64_t UpperBound) : UpperBound(UpperBound) {}
+
+ bool operator()(const AllocaPartitioning::iterator &I) {
+ return I->endOffset() <= UpperBound;
+ }
+ };
+}
+
+static void removeFinishedSplitUses(
+ SmallVectorImpl<AllocaPartitioning::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(),
+ IsPartitionEndLessOrEqualTo(Offset)),
+ SplitUses.end());
+ if (SplitUsesOldSize == SplitUses.size())
+ return;
+
+ // Recompute the max. While this is linear, so is remove_if.
+ MaxSplitUseEndOffset = 0;
+ for (SmallVectorImpl<AllocaPartitioning::iterator>::iterator
+ SUI = SplitUses.begin(),
+ SUE = SplitUses.end();
+ SUI != SUE; ++SUI)
+ MaxSplitUseEndOffset = std::max((*SUI)->endOffset(), MaxSplitUseEndOffset);
+}
+
/// \brief Walks the partitioning of an alloca rewriting uses of each partition.
bool SROA::splitAlloca(AllocaInst &AI, AllocaPartitioning &P) {
+ if (P.begin() == P.end())
+ return false;
+
bool Changed = false;
- for (AllocaPartitioning::iterator PI = P.begin(), PE = P.end(); PI != PE;
- ++PI)
- Changed |= rewriteAllocaPartition(AI, P, PI);
+ SmallVector<AllocaPartitioning::iterator, 4> SplitUses;
+ uint64_t MaxSplitUseEndOffset = 0;
+
+ uint64_t BeginOffset = P.begin()->beginOffset();
+
+ for (AllocaPartitioning::iterator PI = P.begin(), PJ = llvm::next(PI),
+ PE = P.end();
+ PI != PE; PI = PJ) {
+ uint64_t MaxEndOffset = PI->endOffset();
+
+ if (!PI->isSplittable()) {
+ // When we're forming an unsplittable region, it must always start at he
+ // first partitioning use and will extend through its end.
+ assert(BeginOffset == PI->beginOffset());
+
+ // Rewrite a partition including all of the overlapping uses with this
+ // unsplittable partition.
+ while (PJ != PE && PJ->beginOffset() < MaxEndOffset) {
+ if (!PJ->isSplittable())
+ MaxEndOffset = std::max(MaxEndOffset, PJ->endOffset());
+ ++PJ;
+ }
+ } else {
+ assert(PI->isSplittable()); // Established above.
+
+ // Collect all of the overlapping splittable partitions.
+ while (PJ != PE && PJ->beginOffset() < MaxEndOffset &&
+ PJ->isSplittable()) {
+ MaxEndOffset = std::max(MaxEndOffset, PJ->endOffset());
+ ++PJ;
+ }
+
+ // Back up MaxEndOffset and PJ if we ended the span early when
+ // encountering an unsplittable partition.
+ if (PJ != PE && PJ->beginOffset() < MaxEndOffset) {
+ assert(!PJ->isSplittable());
+ MaxEndOffset = PJ->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 partition uses.
+ Changed |= rewritePartitions(AI, P, PI, PJ, BeginOffset,
+ MaxEndOffset, SplitUses);
+
+ removeFinishedSplitUses(SplitUses, MaxSplitUseEndOffset, MaxEndOffset);
+ }
+
+ // Accumulate all the splittable partitions from the [PI,PJ) region which
+ // overlap going forward.
+ for (AllocaPartitioning::iterator PII = PI, PIE = PJ; PII != PIE; ++PII)
+ if (PII->isSplittable() && PII->endOffset() > MaxEndOffset) {
+ SplitUses.push_back(PII);
+ MaxSplitUseEndOffset = std::max(PII->endOffset(), MaxSplitUseEndOffset);
+ }
+
+ // If we're already at the end and we have no split uses, we're done.
+ if (PJ == PE && SplitUses.empty())
+ break;
+
+ // If we have no split uses or no gap in offsets, we're ready to move to
+ // the next partitioning use.
+ if (SplitUses.empty() || (PJ != PE && MaxEndOffset == PJ->beginOffset())) {
+ BeginOffset = PJ->beginOffset();
+ continue;
+ }
+
+ // Even if we have split uses, if the next partitioning use is splittable
+ // and the split uses reach it, we can simply set up the beginning offset
+ // to bridge between them.
+ if (PJ != PE && PJ->isSplittable() && MaxSplitUseEndOffset > PJ->beginOffset()) {
+ BeginOffset = MaxEndOffset;
+ continue;
+ }
+
+ // Otherwise, we have a tail of split uses. Rewrite them with an empty
+ // range of partitioning uses.
+ uint64_t PostSplitEndOffset =
+ PJ == PE ? MaxSplitUseEndOffset : PJ->beginOffset();
+
+ Changed |= rewritePartitions(AI, P, PJ, PJ, MaxEndOffset,
+ PostSplitEndOffset, SplitUses);
+ if (PJ == PE)
+ 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 = PJ->beginOffset();
+ }
return Changed;
}
if (P.begin() == P.end())
return Changed;
- return splitAlloca(AI, P) || Changed;
+ Changed |= splitAlloca(AI, P);
+
+ DEBUG(dbgs() << " Speculating PHIs\n");
+ while (!SpeculatablePHIs.empty())
+ speculatePHINodeLoads(*SpeculatablePHIs.pop_back_val());
+
+ DEBUG(dbgs() << " Speculating Selects\n");
+ while (!SpeculatableSelects.empty())
+ speculateSelectInstLoads(*SpeculatableSelects.pop_back_val());
+
+ return Changed;
}
/// \brief Delete the dead instructions accumulated in this run.
projects / oota-llvm.git / blobdiff