//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
-#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
+#ifndef LLVM_ANALYSIS_SCALAREVOLUTIONEXPANDER_H
+#define LLVM_ANALYSIS_SCALAREVOLUTIONEXPANDER_H
-#include "llvm/BasicBlock.h"
-#include "llvm/Constants.h"
-#include "llvm/Instructions.h"
-#include "llvm/Type.h"
-#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
-#include "llvm/Support/CFG.h"
+#include "llvm/Analysis/ScalarEvolutionNormalization.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/Support/TargetFolder.h"
+#include "llvm/Support/ValueHandle.h"
+#include <set>
namespace llvm {
+ class TargetTransformInfo;
+
+ /// 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 destroying 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<SCEVExpander, Value*> {
+ class SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
ScalarEvolution &SE;
- LoopInfo &LI;
- std::map<SCEVHandle, Value*> InsertedExpressions;
- std::set<Instruction*> InsertedInstructions;
- Instruction *InsertPt;
+ // New instructions receive a name to identifies them with the current pass.
+ const char* IVName;
+
+ std::map<std::pair<const SCEV *, Instruction *>, AssertingVH<Value> >
+ InsertedExpressions;
+ std::set<AssertingVH<Value> > InsertedValues;
+ std::set<AssertingVH<Value> > InsertedPostIncValues;
+
+ /// RelevantLoops - A memoization of the "relevant" loop for a given SCEV.
+ DenseMap<const SCEV *, const Loop *> RelevantLoops;
+
+ /// PostIncLoops - Addrecs referring to any of the given loops are expanded
+ /// in post-inc mode. For example, expanding {1,+,1}<L> in post-inc mode
+ /// returns the add instruction that adds one to the phi for {0,+,1}<L>,
+ /// 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<AssertingVH<PHINode> > 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<true, TargetFolder> BuilderType;
+ BuilderType Builder;
+
+#ifndef NDEBUG
+ const char *DebugType;
+#endif
friend struct SCEVVisitor<SCEVExpander, Value*>;
+
public:
- SCEVExpander(ScalarEvolution &se, LoopInfo &li) : SE(se), LI(li) {}
+ /// 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
+ /// 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 InsertedInstructions.count(I);
+ 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() || Ty->isFloatingPoint()) &&
- "Can only insert integer or floating point induction variables!");
- SCEVHandle H = SCEVAddRecExpr::get(SCEVUnknown::getIntegerSCEV(0, Ty),
- SCEVUnknown::getIntegerSCEV(1, Ty), L);
- return expand(H);
- }
+ PHINode *getOrInsertCanonicalInductionVariable(const Loop *L, Type *Ty);
- /// addInsertedValue - Remember the specified instruction as being the
- /// canonical form for the specified SCEV.
- void addInsertedValue(Instruction *I, SCEV *S) {
- InsertedExpressions[S] = (Value*)I;
- InsertedInstructions.insert(I);
- }
+ /// getIVIncOperand - Return the induction variable increment's IV operand.
+ Instruction *getIVIncOperand(Instruction *IncV, Instruction *InsertPos,
+ bool allowScale);
+
+ /// hoistIVInc - Utility for hoisting an IV increment.
+ bool hoistIVInc(Instruction *IncV, Instruction *InsertPos);
+
+ /// replaceCongruentIVs - replace congruent phis with their most canonical
+ /// representative. Return the number of phis eliminated.
+ unsigned replaceCongruentIVs(Loop *L, const DominatorTree *DT,
+ SmallVectorImpl<WeakVH> &DeadInsts,
+ const TargetTransformInfo *TTI = NULL);
/// expandCodeFor - Insert code to directly compute the specified SCEV
/// expression into the program. The inserted code is inserted into the
/// specified block.
- ///
- /// If a particular value sign is required, a type may be specified for the
- /// result.
- Value *expandCodeFor(SCEVHandle SH, Instruction *IP, const Type *Ty = 0) {
- // Expand the code for this SCEV.
- this->InsertPt = IP;
- return expandInTy(SH, Ty);
- }
+ Value *expandCodeFor(const SCEV *SH, Type *Ty, Instruction *I);
- protected:
- Value *expand(SCEV *S) {
- // Check to see if we already expanded this.
- std::map<SCEVHandle, Value*>::iterator I = InsertedExpressions.find(S);
- if (I != InsertedExpressions.end())
- return I->second;
-
- Value *V = visit(S);
- InsertedExpressions[S] = V;
- return V;
+ /// 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;
}
- Value *expandInTy(SCEV *S, const Type *Ty) {
- Value *V = expand(S);
- if (Ty && V->getType() != Ty) {
- // FIXME: keep track of the cast instruction.
- if (Constant *C = dyn_cast<Constant>(V))
- return ConstantExpr::getCast(C, Ty);
- else if (Instruction *I = dyn_cast<Instruction>(V)) {
- // Check to see if there is already a cast. If there is, use it.
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI) {
- if ((*UI)->getType() == Ty)
- if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) {
- BasicBlock::iterator It = I; ++It;
- if (isa<InvokeInst>(I))
- It = cast<InvokeInst>(I)->getNormalDest()->begin();
- while (isa<PHINode>(It)) ++It;
- if (It != BasicBlock::iterator(CI)) {
- // Splice the cast immediately after the operand in question.
- BasicBlock::InstListType &InstList =
- It->getParent()->getInstList();
- InstList.splice(It, CI->getParent()->getInstList(), CI);
- }
- return CI;
- }
- }
- BasicBlock::iterator IP = I; ++IP;
- if (InvokeInst *II = dyn_cast<InvokeInst>(I))
- IP = II->getNormalDest()->begin();
- while (isa<PHINode>(IP)) ++IP;
- return new CastInst(V, Ty, V->getName(), IP);
- } else {
- // FIXME: check to see if there is already a cast!
- return new CastInst(V, Ty, V->getName(), InsertPt);
- }
- }
- return V;
+ /// 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;
}
- Value *visitConstant(SCEVConstant *S) {
- return S->getValue();
+ /// 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();
}
- Value *visitTruncateExpr(SCEVTruncateExpr *S) {
- Value *V = expand(S->getOperand());
- return new CastInst(V, S->getType(), "tmp.", InsertPt);
+ /// 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();
}
- Value *visitZeroExtendExpr(SCEVZeroExtendExpr *S) {
- Value *V = expandInTy(S->getOperand(),S->getType()->getUnsignedVersion());
- return new CastInst(V, S->getType(), "tmp.", InsertPt);
+ /// 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);
}
- Value *visitAddExpr(SCEVAddExpr *S) {
- const Type *Ty = S->getType();
- Value *V = expandInTy(S->getOperand(S->getNumOperands()-1), Ty);
+ void setChainedPhi(PHINode *PN) { ChainedPhis.insert(PN); }
- // Emit a bunch of add instructions
- for (int i = S->getNumOperands()-2; i >= 0; --i)
- V = BinaryOperator::createAdd(V, expandInTy(S->getOperand(i), Ty),
- "tmp.", InsertPt);
- return V;
- }
+ 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);
+
+ /// 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);
+
+ /// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP
+ /// instead of using ptrtoint+arithmetic+inttoptr.
+ 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);
- Value *visitMulExpr(SCEVMulExpr *S);
+ /// getRelevantLoop - Determine the most "relevant" loop for the given SCEV.
+ const Loop *getRelevantLoop(const SCEV *);
- Value *visitUDivExpr(SCEVUDivExpr *S) {
- const Type *Ty = S->getType();
- Value *LHS = expandInTy(S->getLHS(), Ty);
- Value *RHS = expandInTy(S->getRHS(), Ty);
- return BinaryOperator::createDiv(LHS, RHS, "tmp.", InsertPt);
+ Value *visitConstant(const SCEVConstant *S) {
+ return S->getValue();
}
- Value *visitAddRecExpr(SCEVAddRecExpr *S);
+ Value *visitTruncateExpr(const SCEVTruncateExpr *S);
+
+ Value *visitZeroExtendExpr(const SCEVZeroExtendExpr *S);
+
+ Value *visitSignExtendExpr(const SCEVSignExtendExpr *S);
+
+ Value *visitAddExpr(const SCEVAddExpr *S);
+
+ Value *visitMulExpr(const SCEVMulExpr *S);
+
+ Value *visitUDivExpr(const SCEVUDivExpr *S);
+
+ Value *visitAddRecExpr(const SCEVAddRecExpr *S);
+
+ Value *visitSMaxExpr(const SCEVSMaxExpr *S);
- Value *visitUnknown(SCEVUnknown *S) {
+ Value *visitUMaxExpr(const SCEVUMaxExpr *S);
+
+ 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
-
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