1 //===---- llvm/Analysis/ScalarEvolutionExpander.h - SCEV Exprs --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the classes used to generate code from scalar expressions.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
15 #define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
17 #include "llvm/Instructions.h"
18 #include "llvm/Type.h"
19 #include "llvm/Analysis/ScalarEvolution.h"
20 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
25 /// SCEVExpander - This class uses information about analyze scalars to
26 /// rewrite expressions in canonical form.
28 /// Clients should create an instance of this class when rewriting is needed,
29 /// and destroy it when finished to allow the release of the associated
31 struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
35 std::map<SCEVHandle, Value*> InsertedExpressions;
36 std::set<Instruction*> InsertedInstructions;
38 Instruction *InsertPt;
40 friend struct SCEVVisitor<SCEVExpander, Value*>;
42 SCEVExpander(ScalarEvolution &se, LoopInfo &li, const TargetData &td)
43 : SE(se), LI(li), TD(td) {}
45 LoopInfo &getLoopInfo() const { return LI; }
47 /// clear - Erase the contents of the InsertedExpressions map so that users
48 /// trying to expand the same expression into multiple BasicBlocks or
49 /// different places within the same BasicBlock can do so.
50 void clear() { InsertedExpressions.clear(); }
52 /// isInsertedInstruction - Return true if the specified instruction was
53 /// inserted by the code rewriter. If so, the client should not modify the
55 bool isInsertedInstruction(Instruction *I) const {
56 return InsertedInstructions.count(I);
59 /// getOrInsertCanonicalInductionVariable - This method returns the
60 /// canonical induction variable of the specified type for the specified
61 /// loop (inserting one if there is none). A canonical induction variable
62 /// starts at zero and steps by one on each iteration.
63 Value *getOrInsertCanonicalInductionVariable(const Loop *L, const Type *Ty){
64 assert(Ty->isInteger() && "Can only insert integer induction variables!");
65 SCEVHandle H = SE.getAddRecExpr(SE.getIntegerSCEV(0, Ty),
66 SE.getIntegerSCEV(1, Ty), L);
70 /// addInsertedValue - Remember the specified instruction as being the
71 /// canonical form for the specified SCEV.
72 void addInsertedValue(Instruction *I, SCEV *S) {
73 InsertedExpressions[S] = (Value*)I;
74 InsertedInstructions.insert(I);
77 Instruction *getInsertionPoint() const { return InsertPt; }
79 /// expandCodeFor - Insert code to directly compute the specified SCEV
80 /// expression into the program. The inserted code is inserted into the
82 Value *expandCodeFor(SCEVHandle SH, const Type *Ty, Instruction *IP);
84 /// InsertCastOfTo - Insert a cast of V to the specified type, doing what
85 /// we can to share the casts.
86 Value *InsertCastOfTo(Instruction::CastOps opcode, Value *V,
88 /// InsertBinop - Insert the specified binary operator, doing a small amount
89 /// of work to avoid inserting an obviously redundant operation.
90 static Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
91 Value *RHS, Instruction *InsertPt);
93 Value *expand(SCEV *S);
95 Value *visitConstant(SCEVConstant *S) {
99 Value *visitTruncateExpr(SCEVTruncateExpr *S);
101 Value *visitZeroExtendExpr(SCEVZeroExtendExpr *S);
103 Value *visitSignExtendExpr(SCEVSignExtendExpr *S);
105 Value *visitAddExpr(SCEVAddExpr *S);
107 Value *visitMulExpr(SCEVMulExpr *S);
109 Value *visitUDivExpr(SCEVUDivExpr *S);
111 Value *visitAddRecExpr(SCEVAddRecExpr *S);
113 Value *visitSMaxExpr(SCEVSMaxExpr *S);
115 Value *visitUMaxExpr(SCEVUMaxExpr *S);
117 Value *visitUnknown(SCEVUnknown *S) {
118 return S->getValue();