#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/ValueHandle.h"
+#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
/// Optimization analysis message produced during vectorization. Messages inform
/// the user why vectorization did not occur.
-class VectorizationReport {
+class LoopAccessReport {
std::string Message;
- Instruction *Instr;
+ const Instruction *Instr;
+
+protected:
+ LoopAccessReport(const Twine &Message, const Instruction *I)
+ : Message(Message.str()), Instr(I) {}
public:
- VectorizationReport(Instruction *I = nullptr)
- : Message("loop not vectorized: "), Instr(I) {}
+ LoopAccessReport(const Instruction *I = nullptr) : Instr(I) {}
- template <typename A> VectorizationReport &operator<<(const A &Value) {
+ template <typename A> LoopAccessReport &operator<<(const A &Value) {
raw_string_ostream Out(Message);
Out << Value;
return *this;
}
- Instruction *getInstr() { return Instr; }
+ const Instruction *getInstr() const { return Instr; }
std::string &str() { return Message; }
+ const std::string &str() const { return Message; }
operator Twine() { return Message; }
- /// \brief Emit an analysis note with the debug location from the instruction
- /// in \p Message if available. Otherwise use the location of \p TheLoop.
- static void emitAnalysis(VectorizationReport &Message,
+ /// \brief Emit an analysis note for \p PassName with the debug location from
+ /// the instruction in \p Message if available. Otherwise use the location of
+ /// \p TheLoop.
+ static void emitAnalysis(const LoopAccessReport &Message,
const Function *TheFunction,
- const Loop *TheLoop);
+ const Loop *TheLoop,
+ const char *PassName);
};
/// \brief Collection of parameters shared beetween the Loop Vectorizer and the
static unsigned VectorizationFactor;
/// \brief Interleave factor as overridden by the user.
static unsigned VectorizationInterleave;
+ /// \brief True if force-vector-interleave was specified by the user.
+ static bool isInterleaveForced();
/// \\brief When performing memory disambiguation checks at runtime do not
/// make more than this number of comparisons.
- static const unsigned RuntimeMemoryCheckThreshold;
+ static unsigned RuntimeMemoryCheckThreshold;
};
/// \brief Drive the analysis of memory accesses in the loop
/// Insert a pointer and calculate the start and end SCEVs.
void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr, bool WritePtr,
- unsigned DepSetId, unsigned ASId, ValueToValueMap &Strides);
+ unsigned DepSetId, unsigned ASId,
+ const ValueToValueMap &Strides);
+
+ /// \brief No run-time memory checking is necessary.
+ bool empty() const { return Pointers.empty(); }
+
+ /// \brief Decide whether we need to issue a run-time check for pointer at
+ /// index \p I and \p J to prove their independence.
+ bool needsChecking(unsigned I, unsigned J) const;
+
+ /// \brief Print the list run-time memory checks necessary.
+ void print(raw_ostream &OS, unsigned Depth = 0) const;
/// This flag indicates if we need to add the runtime check.
bool Need;
LoopAccessInfo(Loop *L, ScalarEvolution *SE, const DataLayout *DL,
const TargetLibraryInfo *TLI, AliasAnalysis *AA,
- DominatorTree *DT) :
- TheLoop(L), SE(SE), DL(DL), TLI(TLI), AA(AA), DT(DT), NumLoads(0),
- NumStores(0), MaxSafeDepDistBytes(-1U), CanVecMem(false) {}
-
- /// \brief Analyze the loop. Replaces symbolic strides using Strides.
- void analyzeLoop(ValueToValueMap &Strides);
+ DominatorTree *DT, const ValueToValueMap &Strides);
/// Return true we can analyze the memory accesses in the loop and there are
/// no memory dependence cycles.
- bool canVectorizeMemory() { return CanVecMem; }
+ bool canVectorizeMemory() const { return CanVecMem; }
- RuntimePointerCheck *getRuntimePointerCheck() { return &PtrRtCheck; }
+ const RuntimePointerCheck *getRuntimePointerCheck() const {
+ return &PtrRtCheck;
+ }
/// Return true if the block BB needs to be predicated in order for the loop
/// to be vectorized.
- bool blockNeedsPredication(BasicBlock *BB);
+ static bool blockNeedsPredication(BasicBlock *BB, Loop *TheLoop,
+ DominatorTree *DT);
/// Returns true if the value V is uniform within the loop.
- bool isUniform(Value *V);
+ bool isUniform(Value *V) const;
unsigned getMaxSafeDepDistBytes() const { return MaxSafeDepDistBytes; }
unsigned getNumStores() const { return NumStores; }
/// Returns a pair of instructions where the first element is the first
/// instruction generated in possibly a sequence of instructions and the
/// second value is the final comparator value or NULL if no check is needed.
- std::pair<Instruction *, Instruction *> addRuntimeCheck(Instruction *Loc);
+ std::pair<Instruction *, Instruction *>
+ addRuntimeCheck(Instruction *Loc) const;
/// \brief The diagnostics report generated for the analysis. E.g. why we
/// couldn't analyze the loop.
- Optional<VectorizationReport> &getReport() { return Report; }
+ const Optional<LoopAccessReport> &getReport() const { return Report; }
+
+ /// \brief Print the information about the memory accesses in the loop.
+ void print(raw_ostream &OS, unsigned Depth = 0) const;
+
+ /// \brief Used to ensure that if the analysis was run with speculating the
+ /// value of symbolic strides, the client queries it with the same assumption.
+ /// Only used in DEBUG build but we don't want NDEBUG-dependent ABI.
+ unsigned NumSymbolicStrides;
private:
- void emitAnalysis(VectorizationReport &Message);
+ /// \brief Analyze the loop. Substitute symbolic strides using Strides.
+ void analyzeLoop(const ValueToValueMap &Strides);
+
+ /// \brief Check if the structure of the loop allows it to be analyzed by this
+ /// pass.
+ bool canAnalyzeLoop();
+
+ void emitAnalysis(LoopAccessReport &Message);
/// We need to check that all of the pointers in this list are disjoint
/// at runtime.
/// \brief The diagnostics report generated for the analysis. E.g. why we
/// couldn't analyze the loop.
- Optional<VectorizationReport> Report;
+ Optional<LoopAccessReport> Report;
};
Value *stripIntegerCast(Value *V);
/// Ptr. \p PtrToStride provides the mapping between the pointer value and its
/// stride as collected by LoopVectorizationLegality::collectStridedAccess.
const SCEV *replaceSymbolicStrideSCEV(ScalarEvolution *SE,
- ValueToValueMap &PtrToStride,
+ const ValueToValueMap &PtrToStride,
Value *Ptr, Value *OrigPtr = nullptr);
+/// \brief This analysis provides dependence information for the memory accesses
+/// of a loop.
+///
+/// It runs the analysis for a loop on demand. This can be initiated by
+/// querying the loop access info via LAA::getInfo. getInfo return a
+/// LoopAccessInfo object. See this class for the specifics of what information
+/// is provided.
+class LoopAccessAnalysis : public FunctionPass {
+public:
+ static char ID;
+
+ LoopAccessAnalysis() : FunctionPass(ID) {
+ initializeLoopAccessAnalysisPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnFunction(Function &F) override;
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+ /// \brief Query the result of the loop access information for the loop \p L.
+ ///
+ /// If the client speculates (and then issues run-time checks) for the values
+ /// of symbolic strides, \p Strides provides the mapping (see
+ /// replaceSymbolicStrideSCEV). If there is no cached result available run
+ /// the analysis.
+ const LoopAccessInfo &getInfo(Loop *L, const ValueToValueMap &Strides);
+
+ void releaseMemory() override {
+ // Invalidate the cache when the pass is freed.
+ LoopAccessInfoMap.clear();
+ }
+
+ /// \brief Print the result of the analysis when invoked with -analyze.
+ void print(raw_ostream &OS, const Module *M = nullptr) const override;
+
+private:
+ /// \brief The cache.
+ DenseMap<Loop *, std::unique_ptr<LoopAccessInfo>> LoopAccessInfoMap;
+
+ // The used analysis passes.
+ ScalarEvolution *SE;
+ const DataLayout *DL;
+ const TargetLibraryInfo *TLI;
+ AliasAnalysis *AA;
+ DominatorTree *DT;
+};
} // End llvm namespace
#endif
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