| //===-BlockGenerators.h - Helper to generate code for statements-*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines the BlockGenerator and VectorBlockGenerator classes, which |
| // generate sequential code and vectorized code for a polyhedral statement, |
| // respectively. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef POLLY_BLOCK_GENERATORS_H |
| #define POLLY_BLOCK_GENERATORS_H |
| |
| #include "polly/CodeGen/IRBuilder.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/Analysis/ScalarEvolutionExpressions.h" |
| |
| #include "isl/map.h" |
| |
| #include <vector> |
| |
| struct isl_ast_build; |
| |
| namespace llvm { |
| class Pass; |
| class Region; |
| class ScalarEvolution; |
| } |
| |
| namespace polly { |
| using namespace llvm; |
| class ScopStmt; |
| class MemoryAccess; |
| class IslExprBuilder; |
| |
| typedef DenseMap<const Value *, Value *> ValueMapT; |
| typedef std::vector<ValueMapT> VectorValueMapT; |
| |
| /// @brief Check whether an instruction can be synthesized by the code |
| /// generator. |
| /// |
| /// Some instructions will be recalculated only from information that is code |
| /// generated from the polyhedral representation. For such instructions we do |
| /// not need to ensure that their operands are available during code generation. |
| /// |
| /// @param I The instruction to check. |
| /// @param LI The LoopInfo analysis. |
| /// @param SE The scalar evolution database. |
| /// @param R The region out of which SSA names are parameters. |
| /// @return If the instruction I can be regenerated from its |
| /// scalar evolution representation, return true, |
| /// otherwise return false. |
| bool canSynthesize(const llvm::Instruction *I, const llvm::LoopInfo *LI, |
| llvm::ScalarEvolution *SE, const llvm::Region *R); |
| |
| /// @brief Generate a new basic block for a polyhedral statement. |
| /// |
| /// The only public function exposed is generate(). |
| class BlockGenerator { |
| public: |
| /// @brief Generate a new BasicBlock for a ScopStmt. |
| /// |
| /// @param Builder The LLVM-IR Builder used to generate the statement. The |
| /// code is generated at the location, the Builder points to. |
| /// @param Stmt The statement to code generate. |
| /// @param GlobalMap A map that defines for certain Values referenced from the |
| /// original code new Values they should be replaced with. |
| /// @param P A reference to the pass this function is called from. |
| /// The pass is needed to update other analysis. |
| /// @param LI The loop info for the current function |
| /// @param SE The scalar evolution info for the current function |
| /// @param Build The AST build with the new schedule. |
| /// @param ExprBuilder An expression builder to generate new access functions. |
| static void generate(PollyIRBuilder &Builder, ScopStmt &Stmt, |
| ValueMapT &GlobalMap, LoopToScevMapT <S, Pass *P, |
| LoopInfo &LI, ScalarEvolution &SE, |
| __isl_keep isl_ast_build *Build = nullptr, |
| IslExprBuilder *ExprBuilder = nullptr) { |
| BlockGenerator Generator(Builder, Stmt, P, LI, SE, Build, ExprBuilder); |
| Generator.copyBB(GlobalMap, LTS); |
| } |
| |
| protected: |
| PollyIRBuilder &Builder; |
| ScopStmt &Statement; |
| Pass *P; |
| LoopInfo &LI; |
| ScalarEvolution &SE; |
| isl_ast_build *Build; |
| IslExprBuilder *ExprBuilder; |
| |
| BlockGenerator(PollyIRBuilder &B, ScopStmt &Stmt, Pass *P, LoopInfo &LI, |
| ScalarEvolution &SE, __isl_keep isl_ast_build *Build, |
| IslExprBuilder *ExprBuilder); |
| |
| /// @brief Get the new version of a value. |
| /// |
| /// Given an old value, we first check if a new version of this value is |
| /// available in the BBMap or GlobalMap. In case it is not and the value can |
| /// be recomputed using SCEV, we do so. If we can not recompute a value |
| /// using SCEV, but we understand that the value is constant within the scop, |
| /// we return the old value. If the value can still not be derived, this |
| /// function will assert. |
| /// |
| /// @param Old The old Value. |
| /// @param BBMap A mapping from old values to their new values |
| /// (for values recalculated within this basic block). |
| /// @param GlobalMap A mapping from old values to their new values |
| /// (for values recalculated in the new ScoP, but not |
| /// within this basic block). |
| /// @param LTS A mapping from loops virtual canonical induction |
| /// variable to their new values |
| /// (for values recalculated in the new ScoP, but not |
| /// within this basic block). |
| /// @param L The loop that surrounded the instruction that referenced |
| /// this value in the original code. This loop is used to |
| /// evaluate the scalar evolution at the right scope. |
| /// |
| /// @returns o The old value, if it is still valid. |
| /// o The new value, if available. |
| /// o NULL, if no value is found. |
| Value *getNewValue(const Value *Old, ValueMapT &BBMap, ValueMapT &GlobalMap, |
| LoopToScevMapT <S, Loop *L) const; |
| |
| void copyInstScalar(const Instruction *Inst, ValueMapT &BBMap, |
| ValueMapT &GlobalMap, LoopToScevMapT <S); |
| |
| /// @brief Get the innermost loop that surrounds an instruction. |
| /// |
| /// @param Inst The instruction for which we get the loop. |
| /// @return The innermost loop that surrounds the instruction. |
| Loop *getLoopForInst(const Instruction *Inst); |
| |
| /// @brief Get the new operand address according to access relation of @p MA. |
| Value *getNewAccessOperand(const MemoryAccess &MA); |
| |
| /// @brief Generate the operand address |
| Value *generateLocationAccessed(const Instruction *Inst, const Value *Pointer, |
| ValueMapT &BBMap, ValueMapT &GlobalMap, |
| LoopToScevMapT <S); |
| |
| Value *generateScalarLoad(const LoadInst *load, ValueMapT &BBMap, |
| ValueMapT &GlobalMap, LoopToScevMapT <S); |
| |
| Value *generateScalarStore(const StoreInst *store, ValueMapT &BBMap, |
| ValueMapT &GlobalMap, LoopToScevMapT <S); |
| |
| /// @brief Copy a single Instruction. |
| /// |
| /// This copies a single Instruction and updates references to old values |
| /// with references to new values, as defined by GlobalMap and BBMap. |
| /// |
| /// @param BBMap A mapping from old values to their new values |
| /// (for values recalculated within this basic block). |
| /// @param GlobalMap A mapping from old values to their new values |
| /// (for values recalculated in the new ScoP, but not |
| /// within this basic block). |
| void copyInstruction(const Instruction *Inst, ValueMapT &BBMap, |
| ValueMapT &GlobalMap, LoopToScevMapT <S); |
| |
| /// @brief Copy the basic block. |
| /// |
| /// This copies the entire basic block and updates references to old values |
| /// with references to new values, as defined by GlobalMap. |
| /// |
| /// @param GlobalMap A mapping from old values to their new values |
| /// (for values recalculated in the new ScoP, but not |
| /// within this basic block). |
| void copyBB(ValueMapT &GlobalMap, LoopToScevMapT <S); |
| }; |
| |
| /// @brief Generate a new vector basic block for a polyhedral statement. |
| /// |
| /// The only public function exposed is generate(). |
| class VectorBlockGenerator : BlockGenerator { |
| public: |
| /// @brief Generate a new vector basic block for a ScoPStmt. |
| /// |
| /// This code generation is similar to the normal, scalar code generation, |
| /// except that each instruction is code generated for several vector lanes |
| /// at a time. If possible instructions are issued as actual vector |
| /// instructions, but e.g. for address calculation instructions we currently |
| /// generate scalar instructions for each vector lane. |
| /// |
| /// @param Stmt The statement to code generate. |
| /// @param GlobalMaps A vector of maps that define for certain Values |
| /// referenced from the original code new Values they should |
| /// be replaced with. Each map in the vector of maps is |
| /// used for one vector lane. The number of elements in the |
| /// vector defines the width of the generated vector |
| /// instructions. |
| /// @param Schedule A map from the statement to a schedule where the |
| /// innermost dimension is the dimension of the innermost |
| /// loop containing the statemenet. |
| /// @param P A reference to the pass this function is called from. |
| /// The pass is needed to update other analysis. |
| /// @param LI The loop info for the current function |
| /// @param SE The scalar evolution info for the current function |
| /// @param Build The AST build with the new schedule. |
| /// @param ExprBuilder An expression builder to generate new access functions. |
| static void generate(PollyIRBuilder &B, ScopStmt &Stmt, |
| VectorValueMapT &GlobalMaps, |
| std::vector<LoopToScevMapT> &VLTS, |
| __isl_keep isl_map *Schedule, Pass *P, LoopInfo &LI, |
| ScalarEvolution &SE, |
| __isl_keep isl_ast_build *Build = nullptr, |
| IslExprBuilder *ExprBuilder = nullptr) { |
| VectorBlockGenerator Generator(B, GlobalMaps, VLTS, Stmt, Schedule, P, LI, |
| SE, Build, ExprBuilder); |
| Generator.copyBB(); |
| } |
| |
| private: |
| // This is a vector of global value maps. The first map is used for the first |
| // vector lane, ... |
| // Each map, contains information about Instructions in the old ScoP, which |
| // are recalculated in the new SCoP. When copying the basic block, we replace |
| // all referenes to the old instructions with their recalculated values. |
| VectorValueMapT &GlobalMaps; |
| |
| // This is a vector of loop->scev maps. The first map is used for the first |
| // vector lane, ... |
| // Each map, contains information about Instructions in the old ScoP, which |
| // are recalculated in the new SCoP. When copying the basic block, we replace |
| // all referenes to the old instructions with their recalculated values. |
| // |
| // For example, when the code generator produces this AST: |
| // |
| // for (int c1 = 0; c1 <= 1023; c1 += 1) |
| // for (int c2 = 0; c2 <= 1023; c2 += VF) |
| // for (int lane = 0; lane <= VF; lane += 1) |
| // Stmt(c2 + lane + 3, c1); |
| // |
| // VLTS[lane] contains a map: |
| // "outer loop in the old loop nest" -> SCEV("c2 + lane + 3"), |
| // "inner loop in the old loop nest" -> SCEV("c1"). |
| std::vector<LoopToScevMapT> &VLTS; |
| |
| // A map from the statement to a schedule where the innermost dimension is the |
| // dimension of the innermost loop containing the statemenet. |
| isl_map *Schedule; |
| |
| VectorBlockGenerator(PollyIRBuilder &B, VectorValueMapT &GlobalMaps, |
| std::vector<LoopToScevMapT> &VLTS, ScopStmt &Stmt, |
| __isl_keep isl_map *Schedule, Pass *P, LoopInfo &LI, |
| ScalarEvolution &SE, |
| __isl_keep isl_ast_build *Build = nullptr, |
| IslExprBuilder *ExprBuilder = nullptr); |
| |
| int getVectorWidth(); |
| |
| Value *getVectorValue(const Value *Old, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps, Loop *L); |
| |
| Type *getVectorPtrTy(const Value *V, int Width); |
| |
| /// @brief Load a vector from a set of adjacent scalars |
| /// |
| /// In case a set of scalars is known to be next to each other in memory, |
| /// create a vector load that loads those scalars |
| /// |
| /// %vector_ptr= bitcast double* %p to <4 x double>* |
| /// %vec_full = load <4 x double>* %vector_ptr |
| /// |
| /// @param NegativeStride This is used to indicate a -1 stride. In such |
| /// a case we load the end of a base address and |
| /// shuffle the accesses in reverse order into the |
| /// vector. By default we would do only positive |
| /// strides. |
| /// |
| Value *generateStrideOneLoad(const LoadInst *Load, |
| VectorValueMapT &ScalarMaps, |
| bool NegativeStride); |
| |
| /// @brief Load a vector initialized from a single scalar in memory |
| /// |
| /// In case all elements of a vector are initialized to the same |
| /// scalar value, this value is loaded and shuffeled into all elements |
| /// of the vector. |
| /// |
| /// %splat_one = load <1 x double>* %p |
| /// %splat = shufflevector <1 x double> %splat_one, <1 x |
| /// double> %splat_one, <4 x i32> zeroinitializer |
| /// |
| Value *generateStrideZeroLoad(const LoadInst *Load, ValueMapT &BBMap); |
| |
| /// @brief Load a vector from scalars distributed in memory |
| /// |
| /// In case some scalars a distributed randomly in memory. Create a vector |
| /// by loading each scalar and by inserting one after the other into the |
| /// vector. |
| /// |
| /// %scalar_1= load double* %p_1 |
| /// %vec_1 = insertelement <2 x double> undef, double %scalar_1, i32 0 |
| /// %scalar 2 = load double* %p_2 |
| /// %vec_2 = insertelement <2 x double> %vec_1, double %scalar_1, i32 1 |
| /// |
| Value *generateUnknownStrideLoad(const LoadInst *Load, |
| VectorValueMapT &ScalarMaps); |
| |
| void generateLoad(const LoadInst *Load, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps); |
| |
| void copyUnaryInst(const UnaryInstruction *Inst, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps); |
| |
| void copyBinaryInst(const BinaryOperator *Inst, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps); |
| |
| void copyStore(const StoreInst *Store, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps); |
| |
| void copyInstScalarized(const Instruction *Inst, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps); |
| |
| bool extractScalarValues(const Instruction *Inst, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps); |
| |
| bool hasVectorOperands(const Instruction *Inst, ValueMapT &VectorMap); |
| |
| void copyInstruction(const Instruction *Inst, ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps); |
| |
| void copyBB(); |
| }; |
| } |
| #endif |