X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FAnalysis%2FScalarEvolutionExpander.h;h=9ee3a97bc70df3a138f85373e64a0723c3a81b15;hb=0b8c9a80f20772c3793201ab5b251d3520b9cea3;hp=7e0de47dc4f3b291077592ba17d7c8326b995845;hpb=453aa4fbf1083cc7f646a0ac21e2bcc384a91ae9;p=oota-llvm.git diff --git a/include/llvm/Analysis/ScalarEvolutionExpander.h b/include/llvm/Analysis/ScalarEvolutionExpander.h index 7e0de47dc4f..9ee3a97bc70 100644 --- a/include/llvm/Analysis/ScalarEvolutionExpander.h +++ b/include/llvm/Analysis/ScalarEvolutionExpander.h @@ -14,107 +14,214 @@ #ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H #define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H -#include "llvm/Instructions.h" -#include "llvm/Type.h" -#include "llvm/Analysis/ScalarEvolution.h" #include "llvm/Analysis/ScalarEvolutionExpressions.h" +#include "llvm/Analysis/ScalarEvolutionNormalization.h" +#include "llvm/IR/IRBuilder.h" +#include "llvm/Support/TargetFolder.h" +#include "llvm/Support/ValueHandle.h" +#include namespace llvm { + class TargetLowering; + + /// Return true if the given expression is safe to expand in the sense that + /// all materialized values are safe to speculate. + bool isSafeToExpand(const SCEV *S); + /// SCEVExpander - This class uses information about analyze scalars to /// rewrite expressions in canonical form. /// /// Clients should create an instance of this class when rewriting is needed, - /// and destroy it when finished to allow the release of the associated + /// and destroy it when finished to allow the release of the associated /// memory. - struct SCEVExpander : public SCEVVisitor { + class SCEVExpander : public SCEVVisitor { ScalarEvolution &SE; - std::map > InsertedExpressions; - std::set InsertedValues; - BasicBlock::iterator InsertPt; + // New instructions receive a name to identifies them with the current pass. + const char* IVName; + + std::map, AssertingVH > + InsertedExpressions; + std::set > InsertedValues; + std::set > InsertedPostIncValues; + + /// RelevantLoops - A memoization of the "relevant" loop for a given SCEV. + DenseMap RelevantLoops; + + /// PostIncLoops - Addrecs referring to any of the given loops are expanded + /// in post-inc mode. For example, expanding {1,+,1} in post-inc mode + /// returns the add instruction that adds one to the phi for {0,+,1}, + /// as opposed to a new phi starting at 1. This is only supported in + /// non-canonical mode. + PostIncLoopSet PostIncLoops; + + /// IVIncInsertPos - When this is non-null, addrecs expanded in the + /// loop it indicates should be inserted with increments at + /// IVIncInsertPos. + const Loop *IVIncInsertLoop; + + /// IVIncInsertPos - When expanding addrecs in the IVIncInsertLoop loop, + /// insert the IV increment at this position. + Instruction *IVIncInsertPos; + + /// Phis that complete an IV chain. Reuse + std::set > ChainedPhis; + + /// CanonicalMode - When true, expressions are expanded in "canonical" + /// form. In particular, addrecs are expanded as arithmetic based on + /// a canonical induction variable. When false, expression are expanded + /// in a more literal form. + bool CanonicalMode; + + /// When invoked from LSR, the expander is in "strength reduction" mode. The + /// only difference is that phi's are only reused if they are already in + /// "expanded" form. + bool LSRMode; + + typedef IRBuilder BuilderType; + BuilderType Builder; + +#ifndef NDEBUG + const char *DebugType; +#endif friend struct SCEVVisitor; + public: - explicit SCEVExpander(ScalarEvolution &se) - : SE(se) {} + /// SCEVExpander - Construct a SCEVExpander in "canonical" mode. + explicit SCEVExpander(ScalarEvolution &se, const char *name) + : SE(se), IVName(name), IVIncInsertLoop(0), IVIncInsertPos(0), + CanonicalMode(true), LSRMode(false), + Builder(se.getContext(), TargetFolder(se.TD)) { +#ifndef NDEBUG + DebugType = ""; +#endif + } + +#ifndef NDEBUG + void setDebugType(const char* s) { DebugType = s; } +#endif /// clear - Erase the contents of the InsertedExpressions map so that users /// trying to expand the same expression into multiple BasicBlocks or /// different places within the same BasicBlock can do so. - void clear() { InsertedExpressions.clear(); } - - /// isInsertedInstruction - Return true if the specified instruction was - /// inserted by the code rewriter. If so, the client should not modify the - /// instruction. - bool isInsertedInstruction(Instruction *I) const { - return InsertedValues.count(I); - } - - /// isInsertedExpression - Return true if the the code rewriter has a - /// Value* recorded for the given expression. - bool isInsertedExpression(const SCEV *S) const { - return InsertedExpressions.count(S); + void clear() { + InsertedExpressions.clear(); + InsertedValues.clear(); + InsertedPostIncValues.clear(); + ChainedPhis.clear(); } /// getOrInsertCanonicalInductionVariable - This method returns the /// canonical induction variable of the specified type for the specified /// loop (inserting one if there is none). A canonical induction variable /// starts at zero and steps by one on each iteration. - Value *getOrInsertCanonicalInductionVariable(const Loop *L, const Type *Ty){ - assert(Ty->isInteger() && "Can only insert integer induction variables!"); - SCEVHandle H = SE.getAddRecExpr(SE.getIntegerSCEV(0, Ty), - SE.getIntegerSCEV(1, Ty), L); - return expand(H); - } - - /// addInsertedValue - Remember the specified instruction as being the - /// canonical form for the specified SCEV. - void addInsertedValue(Value *V, const SCEV *S) { - InsertedExpressions[S] = V; - InsertedValues.insert(V); - } + PHINode *getOrInsertCanonicalInductionVariable(const Loop *L, Type *Ty); - void setInsertionPoint(BasicBlock::iterator NewIP) { InsertPt = NewIP; } + /// getIVIncOperand - Return the induction variable increment's IV operand. + Instruction *getIVIncOperand(Instruction *IncV, Instruction *InsertPos, + bool allowScale); - BasicBlock::iterator getInsertionPoint() const { return InsertPt; } + /// hoistIVInc - Utility for hoisting an IV increment. + bool hoistIVInc(Instruction *IncV, Instruction *InsertPos); - /// expandCodeFor - Insert code to directly compute the specified SCEV - /// expression into the program. The inserted code is inserted into the - /// SCEVExpander's current insertion point. If a type is specified, the - /// result will be expanded to have that type, with a cast if necessary. - Value *expandCodeFor(SCEVHandle SH, const Type *Ty = 0); + /// replaceCongruentIVs - replace congruent phis with their most canonical + /// representative. Return the number of phis eliminated. + unsigned replaceCongruentIVs(Loop *L, const DominatorTree *DT, + SmallVectorImpl &DeadInsts, + const TargetLowering *TLI = NULL); /// expandCodeFor - Insert code to directly compute the specified SCEV /// expression into the program. The inserted code is inserted into the /// specified block. - Value *expandCodeFor(SCEVHandle SH, const Type *Ty, - BasicBlock::iterator IP) { - setInsertionPoint(IP); - return expandCodeFor(SH, Ty); + Value *expandCodeFor(const SCEV *SH, Type *Ty, Instruction *I); + + /// setIVIncInsertPos - Set the current IV increment loop and position. + void setIVIncInsertPos(const Loop *L, Instruction *Pos) { + assert(!CanonicalMode && + "IV increment positions are not supported in CanonicalMode"); + IVIncInsertLoop = L; + IVIncInsertPos = Pos; } - /// InsertCastOfTo - Insert a cast of V to the specified type, doing what - /// we can to share the casts. - Value *InsertCastOfTo(Instruction::CastOps opcode, Value *V, - const Type *Ty); + /// setPostInc - Enable post-inc expansion for addrecs referring to the + /// given loops. Post-inc expansion is only supported in non-canonical + /// mode. + void setPostInc(const PostIncLoopSet &L) { + assert(!CanonicalMode && + "Post-inc expansion is not supported in CanonicalMode"); + PostIncLoops = L; + } - /// InsertNoopCastOfTo - Insert a cast of V to the specified type, - /// which must be possible with a noop cast. - Value *InsertNoopCastOfTo(Value *V, const Type *Ty); + /// clearPostInc - Disable all post-inc expansion. + void clearPostInc() { + PostIncLoops.clear(); + + // When we change the post-inc loop set, cached expansions may no + // longer be valid. + InsertedPostIncValues.clear(); + } + + /// disableCanonicalMode - Disable the behavior of expanding expressions in + /// canonical form rather than in a more literal form. Non-canonical mode + /// is useful for late optimization passes. + void disableCanonicalMode() { CanonicalMode = false; } + + void enableLSRMode() { LSRMode = true; } + + /// clearInsertPoint - Clear the current insertion point. This is useful + /// if the instruction that had been serving as the insertion point may + /// have been deleted. + void clearInsertPoint() { + Builder.ClearInsertionPoint(); + } + + /// isInsertedInstruction - Return true if the specified instruction was + /// inserted by the code rewriter. If so, the client should not modify the + /// instruction. + bool isInsertedInstruction(Instruction *I) const { + return InsertedValues.count(I) || InsertedPostIncValues.count(I); + } + + void setChainedPhi(PHINode *PN) { ChainedPhis.insert(PN); } + + private: + LLVMContext &getContext() const { return SE.getContext(); } /// InsertBinop - Insert the specified binary operator, doing a small amount /// of work to avoid inserting an obviously redundant operation. - Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, - Value *RHS, BasicBlock::iterator InsertPt); + Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS); + + /// ReuseOrCreateCast - Arange for there to be a cast of V to Ty at IP, + /// reusing an existing cast if a suitable one exists, moving an existing + /// cast if a suitable one exists but isn't in the right place, or + /// or creating a new one. + Value *ReuseOrCreateCast(Value *V, Type *Ty, + Instruction::CastOps Op, + BasicBlock::iterator IP); + + /// InsertNoopCastOfTo - Insert a cast of V to the specified type, + /// which must be possible with a noop cast, doing what we can to + /// share the casts. + Value *InsertNoopCastOfTo(Value *V, Type *Ty); - private: /// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP /// instead of using ptrtoint+arithmetic+inttoptr. - Value *expandAddToGEP(const SCEVHandle *op_begin, const SCEVHandle *op_end, - const PointerType *PTy, const Type *Ty, Value *V); + Value *expandAddToGEP(const SCEV *const *op_begin, + const SCEV *const *op_end, + PointerType *PTy, Type *Ty, Value *V); Value *expand(const SCEV *S); + /// expandCodeFor - Insert code to directly compute the specified SCEV + /// expression into the program. The inserted code is inserted into the + /// SCEVExpander's current insertion point. If a type is specified, the + /// result will be expanded to have that type, with a cast if necessary. + Value *expandCodeFor(const SCEV *SH, Type *Ty = 0); + + /// getRelevantLoop - Determine the most "relevant" loop for the given SCEV. + const Loop *getRelevantLoop(const SCEV *); + Value *visitConstant(const SCEVConstant *S) { return S->getValue(); } @@ -140,8 +247,23 @@ namespace llvm { Value *visitUnknown(const SCEVUnknown *S) { return S->getValue(); } + + void rememberInstruction(Value *I); + + void restoreInsertPoint(BasicBlock *BB, BasicBlock::iterator I); + + bool isNormalAddRecExprPHI(PHINode *PN, Instruction *IncV, const Loop *L); + + bool isExpandedAddRecExprPHI(PHINode *PN, Instruction *IncV, const Loop *L); + + Value *expandAddRecExprLiterally(const SCEVAddRecExpr *); + PHINode *getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized, + const Loop *L, + Type *ExpandTy, + Type *IntTy); + Value *expandIVInc(PHINode *PN, Value *StepV, const Loop *L, + Type *ExpandTy, Type *IntTy, bool useSubtract); }; } #endif -