[llvm] r186316 - Reimplement SROA yet again. Same fundamental principle, but a totally
Benjamin Kramer
benny.kra at gmail.com
Mon Jul 15 07:56:01 PDT 2013
On 15.07.2013, at 12:30, Chandler Carruth <chandlerc at gmail.com> wrote:
> Author: chandlerc
> Date: Mon Jul 15 05:30:19 2013
> New Revision: 186316
>
> URL: http://llvm.org/viewvc/llvm-project?rev=186316&view=rev
> Log:
> Reimplement SROA yet again. Same fundamental principle, but a totally
> different core implementation strategy.
>
> Previously, SROA would build a relatively elaborate partitioning of an
> alloca, associate uses with each partition, and then rewrite the uses of
> each partition in an attempt to break apart the alloca into chunks that
> could be promoted. This was very wasteful in terms of memory and compile
> time because regardless of how complex the alloca or how much we're able
> to do in breaking it up, all of the datastructure work to analyze the
> partitioning was done up front.
>
> The new implementation attempts to form partitions of the alloca lazily
> and on the fly, rewriting the uses that make up that partition as it
> goes. This has a few significant effects:
> 1) Much simpler data structures are used throughout.
> 2) No more double walk of the recursive use graph of the alloca, only
> walk it once.
> 3) No more complex algorithms for associating a particular use with
> a particular partition.
> 4) PHI and Select speculation is simplified and happens lazily.
> 5) More precise information is available about a specific use of the
> alloca, removing the need for some side datastructures.
>
> Ultimately, I think this is a much better implementation. It removes
> about 300 lines of code, but arguably removes more like 500 considering
> that some code grew in the process of being factored apart and cleaned
> up for this all to work.
>
> I've re-used as much of the old implementation as possible, which
> includes the lion's share of code in the form of the rewriting logic.
> The interesting new logic centers around how the uses of a partition are
> sorted, and split into actual partitions.
>
> Each instruction using a pointer derived from the alloca gets
> a 'Partition' entry. This name is totally wrong, but I'll do a rename in
> a follow-up commit as there is already enough churn here. The entry
> describes the offset range accessed and the nature of the access. Once
> we have all of these entries we sort them in a very specific way:
> increasing order of begin offset, followed by whether they are
> splittable uses (memcpy, etc), followed by the end offset or whatever.
> Sorting by splittability is important as it simplifies the collection of
> uses into a partition.
>
> Once we have these uses sorted, we walk from the beginning to the end
> building up a range of uses that form a partition of the alloca.
> Overlapping unsplittable uses are merged into a single partition while
> splittable uses are broken apart and carried from one partition to the
> next. A partition is also introduced to bridge splittable uses between
> the unsplittable regions when necessary.
>
> I've looked at the performance PRs fairly closely. PR15471 no longer
> will even load (the module is invalid). Not sure what is up there.
> PR15412 improves by between 5% and 10%, however it is nearly impossible
> to know what is holding it up as SROA (the entire pass) takes less time
> than reading the IR for that test case. The analysis takes the same time
> as running mem2reg on the final allocas. I suspect (without much
> evidence) that the new implementation will scale much better however,
> and it is just the small nature of the test cases that makes the changes
> small and noisy. Either way, it is still simpler and cleaner I think.
The buildbot is behaving a bit weirdly but this seems to have broken bullet in the nightly tester:
http://lab.llvm.org:8011/builders/clang-x86_64-darwin12-nt-O3/builds/602
Assertion failed: (CanSROA), function visit, file /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/llvm.src/lib/Transforms/Scalar/SROA.cpp, line 1954.
Stack dump:
0. Program arguments: /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/llvm.install.1/bin/clang -cc1 -triple x86_64-apple-macosx10.8.0 -emit-obj -disable-free -main-file-name btGImpactCollisionAlgorithm.cpp -mrelocation-model dynamic-no-pic -pic-level 2 -masm-verbose -munwind-tables -target-cpu core2 -target-linker-version 136 -coverage-file /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/tests/nt/build/sample-0/MultiSource/Benchmarks/Bullet/Output/btGImpactCollisionAlgorithm.llvm.o -resource-dir /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/llvm.install.1/bin/../lib/clang/3.4 -D NO_TIME -D _GNU_SOURCE -D __STDC_LIMIT_MACROS -D NDEBUG -I /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/test-suite/MultiSource/Benchmarks/Bullet/include -I /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/tests/nt/build/sample-0/MultiSource/Benchmarks/Bullet -I /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/test-suite/MultiSource/Benchmarks/Bullet -I /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/test-suite/include -I ../../..//include -O3 -fdeprecated-macro -fdebug-compilation-dir /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/tests/nt/build/sample-0/MultiSource/Benchmarks/Bullet -ferror-limit 19 -fmessage-length 0 -stack-protector 1 -mstackrealign -fblocks -fobjc-runtime=macosx-10.8.0 -fobjc-dispatch-method=mixed -fobjc-default-synthesize-properties -fencode-extended-block-signature -fcxx-exceptions -fexceptions -fdiagnostics-show-option -vectorize-loops -o Output/btGImpactCollisionAlgorithm.llvm.o -x c++ /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/clang-x86_64-darwin12-nt-O3/test-suite/MultiSource/Benchmarks/Bullet/btGImpactCollisionAlgorithm.cpp
- Ben
> Modified:
> llvm/trunk/lib/Transforms/Scalar/SROA.cpp
> llvm/trunk/test/Transforms/SROA/basictest.ll
>
> Modified: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SROA.cpp?rev=186316&r1=186315&r2=186316&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Scalar/SROA.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp Mon Jul 15 05:30:19 2013
> @@ -47,6 +47,7 @@
> #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"
> @@ -110,17 +111,40 @@ typedef llvm::IRBuilder<false, ConstantF
> }
>
> 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.
> ///
> @@ -128,99 +152,37 @@ struct ByteRange {
> /// 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;
> + const Partition &RHS) {
> + return LHSOffset < RHS.beginOffset();
> }
>
> - bool operator==(const ByteRange &RHS) const {
> - return BeginOffset == RHS.BeginOffset && EndOffset == RHS.EndOffset;
> + bool operator==(const Partition &RHS) const {
> + return isSplittable() == RHS.isSplittable() &&
> + beginOffset() == RHS.beginOffset() && endOffset() == RHS.endOffset();
> }
> - bool operator!=(const ByteRange &RHS) const { return !operator==(RHS); }
> + bool operator!=(const Partition &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;
> - }
> -
> - /// \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;
> - }
> -
> - 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(); }
> -};
> -}
> +} // 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 {
> @@ -257,46 +219,6 @@ public:
> 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
> @@ -320,66 +242,12 @@ public:
> 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;
> @@ -389,8 +257,6 @@ private:
> 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.
> @@ -414,14 +280,6 @@ private:
> /// 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
> @@ -439,26 +297,6 @@ private:
> /// 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();
> };
> }
>
> @@ -489,6 +327,10 @@ class AllocaPartitioning::PartitionBuild
> 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)
> @@ -497,6 +339,11 @@ public:
> 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
> @@ -507,7 +354,7 @@ private:
> << AllocSize << " byte alloca:\n"
> << " alloca: " << P.AI << "\n"
> << " use: " << I << "\n");
> - return;
> + return markAsDead(I);
> }
>
> uint64_t BeginOffset = Offset.getZExtValue();
> @@ -528,8 +375,21 @@ private:
> 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,
> @@ -582,7 +442,7 @@ private:
> << " byte alloca:\n"
> << " alloca: " << P.AI << "\n"
> << " use: " << SI << "\n");
> - return;
> + return markAsDead(SI);
> }
>
> assert((!SI.isSimple() || ValOp->getType()->isSingleValueType()) &&
> @@ -597,7 +457,7 @@ private:
> 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);
> @@ -613,7 +473,7 @@ private:
> 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);
> @@ -622,63 +482,44 @@ private:
> 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);
> + insertUse(II, Offset, Size, /*IsSplittable=*/Inserted && Length);
>
> - // 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;
> - }
> + // 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.
> @@ -747,33 +588,45 @@ private:
>
> 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;
> + 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);
> }
>
> - // Check for an unsafe use of the PHI node.
> - if (Instruction *UnsafeI = hasUnsafePHIOrSelectUse(&PN, PHIInfo.first))
> - return PI.setAborted(UnsafeI);
> + // For PHI and select operands outside the alloca, we can't nuke the entire
> + // phi or select -- the other side might still be relevant, so we special
> + // case them here and use a separate structure to track the operands
> + // themselves which should be replaced with undef.
> + // FIXME: This should instead be escaped in the event we're instrumenting
> + // for address sanitization.
> + if ((Offset.isNegative() && (-Offset).uge(PHISize)) ||
> + (!Offset.isNegative() && Offset.uge(AllocSize))) {
> + P.DeadOperands.push_back(U);
> + return;
> + }
>
> - insertUse(PN, Offset, PHIInfo.first);
> + insertUse(PN, Offset, PHISize);
> }
>
> void visitSelectInst(SelectInst &SI) {
> if (SI.use_empty())
> - return;
> + return markAsDead(SI);
> if (Value *Result = foldSelectInst(SI)) {
> if (Result == *U)
> // If the result of the constant fold will be the pointer, recurse
> // through the select as if we had RAUW'ed it.
> enqueueUsers(SI);
> + else
> + // Otherwise the operand to the select is dead, and we can replace it
> + // with undef.
> + P.DeadOperands.push_back(U);
>
> return;
> }
> @@ -781,316 +634,38 @@ private:
> 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 &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);
> }
> - }
> -
> - 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(SelectSize)) ||
> (!Offset.isNegative() && Offset.uge(AllocSize))) {
> P.DeadOperands.push_back(U);
> return;
> }
>
> - insertUse(User, Offset, Size);
> + insertUse(SI, Offset, SelectSize);
> }
>
> - void visitPHINode(PHINode &PN) {
> - if (PN.use_empty())
> - return markAsDead(PN);
> -
> - assert(IsOffsetKnown);
> - insertPHIOrSelect(PN, Offset);
> - }
> -
> - void visitSelectInst(SelectInst &SI) {
> - if (SI.use_empty())
> - return markAsDead(SI);
> -
> - if (Value *Result = foldSelectInst(SI)) {
> - if (Result == *U)
> - // If the result of the constant fold will be the pointer, recurse
> - // through the select as if we had RAUW'ed it.
> - enqueueUsers(SI);
> - else
> - // Otherwise the operand to the select is dead, and we can replace it
> - // with undef.
> - P.DeadOperands.push_back(U);
> -
> - return;
> - }
> -
> - assert(IsOffsetKnown);
> - insertPHIOrSelect(SI, Offset);
> - }
> -
> - /// \brief Unreachable, we've already visited the alloca once.
> + /// \brief Disable SROA entirely if there are unhandled users of the alloca.
> void visitInstruction(Instruction &I) {
> - llvm_unreachable("Unhandled instruction in use builder.");
> + PI.setAborted(&I);
> }
> };
>
> -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);
> - }
> -
> - // 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;
> - }
> -
> - New.BeginOffset = New.EndOffset;
> - if (!New.IsSplittable) {
> - New.EndOffset = std::max(New.EndOffset, SplitEndOffset);
> - if (j != e && !Partitions[j].IsSplittable)
> - New.EndOffset = std::min(New.EndOffset, Partitions[j].BeginOffset);
> - New.IsSplittable = true;
> - // If there is a trailing splittable partition which won't be fused into
> - // the next splittable partition go ahead and add it onto the partitions
> - // list.
> - if (New.BeginOffset < New.EndOffset &&
> - (j == e || !Partitions[j].IsSplittable ||
> - New.EndOffset < Partitions[j].BeginOffset)) {
> - Partitions.push_back(New);
> - New.BeginOffset = New.EndOffset = 0ull;
> - }
> - }
> - }
> -
> - // Re-sort the partitions now that they have been split and merged into
> - // disjoint set of partitions. Also remove any of the dead partitions we've
> - // replaced in the process.
> - std::sort(Partitions.begin(), Partitions.end());
> - if (NumDeadPartitions) {
> - assert(Partitions.back().isDead());
> - assert((ptrdiff_t)NumDeadPartitions ==
> - std::count(Partitions.begin(), Partitions.end(), Partitions.back()));
> - }
> - 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)
> @@ -1114,122 +689,37 @@ AllocaPartitioning::AllocaPartitioning(c
> // 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();
> - }
> -
> - // 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;
> + Partitions.erase(
> + std::remove_if(Partitions.begin(), Partitions.end(), IsPartitionDead()),
> + Partitions.end());
>
> - Ty = UserTy;
> - }
> - return Ty;
> + // Record how many partitions we end up with.
> + NumAllocaPartitions += Partitions.size();
> + MaxPartitionsPerAlloca = std::max<unsigned>(Partitions.size(), MaxPartitionsPerAlloca);
> +
> + 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";
> -}
> -
> -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";
> - }
> - }
> + 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::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 {
> @@ -1241,10 +731,8 @@ void AllocaPartitioning::print(raw_ostre
> }
>
> 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); }
> @@ -1252,7 +740,6 @@ void AllocaPartitioning::dump() const {
>
> #endif // !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
>
> -
> namespace {
> /// \brief Implementation of LoadAndStorePromoter for promoting allocas.
> ///
> @@ -1390,6 +877,21 @@ class SROA : public FunctionPass {
> /// \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),
> @@ -1407,9 +909,11 @@ private:
> 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);
> @@ -1429,286 +933,247 @@ INITIALIZE_PASS_DEPENDENCY(DominatorTree
> 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>;
> -
> - const DataLayout &TD;
> - AllocaPartitioning &P;
> - SROA &Pass;
> +/// 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;
>
> -public:
> - PHIOrSelectSpeculator(const DataLayout &TD, AllocaPartitioning &P, SROA &Pass)
> - : TD(TD), P(P), Pass(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.
>
> - /// \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.
> + 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;
>
> - visit(cast<Instruction>(PU.getUse()->getUser()));
> + // 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;
> }
> - }
> -
> -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);
> - }
> -
> - // 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");
> -
> - // 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();
> + // 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;
>
> - // 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 false;
> + }
>
> - // Try to lookup and rewrite any partition uses corresponding to this phi
> - // input.
> - AllocaPartitioning::iterator PI
> - = P.findPartitionForPHIOrSelectOperand(InUse);
> - if (PI == P.end())
> - continue;
> + return true;
> +}
>
> - // 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);
> - }
> +static void speculatePHINodeLoads(PHINode &PN) {
> + DEBUG(dbgs() << " original: " << PN << "\n");
>
> - return true;
> - }
> + 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();
> +}
> +
> +/// 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;
>
> - void visitSelectInst(SelectInst &SI) {
> - DEBUG(dbgs() << " original: " << SI << "\n");
> + // 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;
> + }
>
> - // 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.
> @@ -2024,6 +1489,73 @@ static Value *convertValue(const DataLay
> 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
> @@ -2032,13 +1564,11 @@ static Value *convertValue(const DataLay
> /// 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;
> @@ -2053,54 +1583,85 @@ static bool isVectorPromotionViable(cons
> "vector size not a multiple of element size?");
> ElementSize /= 8;
>
> - for (; I != E; ++I) {
> - Use *U = I->getUse();
> - if (!U)
> - continue; // Skip dead use.
> + for (; I != E; ++I)
> + if (!isVectorPromotionViableForPartitioning(
> + TD, P, PartitionBeginOffset, PartitionEndOffset, Ty, ElementSize,
> + I))
> + return false;
>
> - uint64_t BeginOffset = I->BeginOffset - PartitionBeginOffset;
> - uint64_t BeginIndex = BeginOffset / ElementSize;
> - if (BeginIndex * ElementSize != BeginOffset ||
> - BeginIndex >= Ty->getNumElements())
> - return false;
> - uint64_t EndOffset = I->EndOffset - PartitionBeginOffset;
> - uint64_t EndIndex = EndOffset / ElementSize;
> - if (EndIndex * ElementSize != EndOffset ||
> - EndIndex > Ty->getNumElements())
> + 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())
> + 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, PartitionTy, LI->getType()))
> - return false;
> - } else if (StoreInst *SI = dyn_cast<StoreInst>(U->getUser())) {
> - if (SI->isVolatile())
> - 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;
> }
>
> @@ -2110,12 +1671,12 @@ static bool isVectorPromotionViable(cons
> /// 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)
> @@ -2133,74 +1694,34 @@ static bool isIntegerWideningViable(cons
> !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;
> }
>
> @@ -2345,6 +1866,7 @@ class AllocaPartitionRewriter : public I
> 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;
> @@ -2374,6 +1896,7 @@ class AllocaPartitionRewriter : public I
>
> // The offset of the partition user currently being rewritten.
> uint64_t BeginOffset, EndOffset;
> + bool IsSplittable;
> bool IsSplit;
> Use *OldUse;
> Instruction *OldPtr;
> @@ -2384,78 +1907,70 @@ class AllocaPartitionRewriter : public I
>
> 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) +
> - ".");
> + 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) {
> - assert(CanSROA);
> - VecTy = 0;
> - ElementTy = 0;
> - ElementSize = 0;
> - }
> - if (IntTy) {
> + 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.
> @@ -2466,12 +1981,6 @@ private:
> 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.
> ///
> @@ -2482,14 +1991,6 @@ private:
> 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;
> @@ -2505,9 +2006,10 @@ private:
> 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(),
> @@ -2515,15 +2017,16 @@ private:
> 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;
> @@ -2534,25 +2037,32 @@ private:
> 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);
> @@ -2574,7 +2084,7 @@ private:
> // 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);
> @@ -2589,11 +2099,12 @@ private:
> 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!");
> @@ -2616,7 +2127,8 @@ private:
> 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()) {
> @@ -2649,37 +2161,45 @@ private:
> 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);
> @@ -2730,9 +2250,12 @@ private:
> // 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;
> @@ -2744,21 +2267,27 @@ private:
> 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;
> @@ -2775,8 +2304,8 @@ private:
> // 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!");
> @@ -2795,7 +2324,7 @@ private:
> // set integer.
> assert(!II.isVolatile());
>
> - uint64_t Size = EndOffset - BeginOffset;
> + uint64_t Size = NewEndOffset - NewBeginOffset;
> V = getIntegerSplat(II.getValue(), Size);
>
> if (IntTy && (BeginOffset != NewAllocaBeginOffset ||
> @@ -2803,8 +2332,7 @@ private:
> 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 &&
> @@ -2813,8 +2341,8 @@ private:
> 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))
> @@ -2836,21 +2364,25 @@ private:
>
> 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
> @@ -2859,12 +2391,14 @@ private:
> // 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));
> @@ -2882,24 +2416,21 @@ private:
> // 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.
> @@ -2920,11 +2451,11 @@ private:
> // 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,
> @@ -2940,11 +2471,11 @@ private:
> 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;
> @@ -2975,8 +2506,7 @@ private:
> 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(),
> @@ -2991,8 +2521,7 @@ private:
> 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);
> }
> @@ -3010,13 +2539,20 @@ private:
> 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);
> @@ -3030,6 +2566,8 @@ private:
>
> 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
> @@ -3039,21 +2577,33 @@ private:
> 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);
> @@ -3062,7 +2612,16 @@ private:
>
> 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.
> }
>
> };
> @@ -3432,57 +2991,52 @@ static Type *getTypePartition(const Data
> /// 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) {
> @@ -3491,54 +3045,207 @@ bool SROA::rewriteAllocaPartition(Alloca
> // 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();
> + unsigned SPOldSize = SpeculatablePHIs.size();
> + unsigned SSOldSize = SpeculatableSelects.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) {
> + 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 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;
> }
> @@ -3601,7 +3308,17 @@ bool SROA::runOnAlloca(AllocaInst &AI) {
> 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.
>
> Modified: llvm/trunk/test/Transforms/SROA/basictest.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SROA/basictest.ll?rev=186316&r1=186315&r2=186316&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/SROA/basictest.ll (original)
> +++ llvm/trunk/test/Transforms/SROA/basictest.ll Mon Jul 15 05:30:19 2013
> @@ -1308,7 +1308,7 @@ end:
>
> define void @PR15805(i1 %a, i1 %b) {
> ; CHECK-LABEL: @PR15805(
> -; CHECK: select i1 undef, i64* %c, i64* %c
> +; CHECK-NOT: alloca
> ; CHECK: ret void
>
> %c = alloca i64, align 8
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
More information about the llvm-commits
mailing list