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"
23 /// SCEVExpander - This class uses information about analyze scalars to
24 /// rewrite expressions in canonical form.
26 /// Clients should create an instance of this class when rewriting is needed,
27 /// and destroy it when finished to allow the release of the associated
29 struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
32 std::map<SCEVHandle, Value*> InsertedExpressions;
33 std::set<Instruction*> InsertedInstructions;
35 Instruction *InsertPt;
37 friend struct SCEVVisitor<SCEVExpander, Value*>;
39 SCEVExpander(ScalarEvolution &se, LoopInfo &li) : SE(se), LI(li) {}
41 LoopInfo &getLoopInfo() const { return LI; }
43 /// clear - Erase the contents of the InsertedExpressions map so that users
44 /// trying to expand the same expression into multiple BasicBlocks or
45 /// different places within the same BasicBlock can do so.
46 void clear() { InsertedExpressions.clear(); }
48 /// isInsertedInstruction - Return true if the specified instruction was
49 /// inserted by the code rewriter. If so, the client should not modify the
51 bool isInsertedInstruction(Instruction *I) const {
52 return InsertedInstructions.count(I);
55 /// getOrInsertCanonicalInductionVariable - This method returns the
56 /// canonical induction variable of the specified type for the specified
57 /// loop (inserting one if there is none). A canonical induction variable
58 /// starts at zero and steps by one on each iteration.
59 Value *getOrInsertCanonicalInductionVariable(const Loop *L, const Type *Ty){
60 assert(Ty->isInteger() && "Can only insert integer induction variables!");
61 SCEVHandle H = SE.getAddRecExpr(SE.getIntegerSCEV(0, Ty),
62 SE.getIntegerSCEV(1, Ty), L);
66 /// addInsertedValue - Remember the specified instruction as being the
67 /// canonical form for the specified SCEV.
68 void addInsertedValue(Instruction *I, SCEV *S) {
69 InsertedExpressions[S] = (Value*)I;
70 InsertedInstructions.insert(I);
73 Instruction *getInsertionPoint() const { return InsertPt; }
75 /// expandCodeFor - Insert code to directly compute the specified SCEV
76 /// expression into the program. The inserted code is inserted into the
78 Value *expandCodeFor(SCEVHandle SH, Instruction *IP);
80 /// InsertCastOfTo - Insert a cast of V to the specified type, doing what
81 /// we can to share the casts.
82 static Value *InsertCastOfTo(Instruction::CastOps opcode, Value *V,
84 /// InsertBinop - Insert the specified binary operator, doing a small amount
85 /// of work to avoid inserting an obviously redundant operation.
86 static Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
87 Value *RHS, Instruction *InsertPt);
89 Value *expand(SCEV *S);
91 Value *visitConstant(SCEVConstant *S) {
95 Value *visitTruncateExpr(SCEVTruncateExpr *S);
97 Value *visitZeroExtendExpr(SCEVZeroExtendExpr *S);
99 Value *visitSignExtendExpr(SCEVSignExtendExpr *S);
101 Value *visitAddExpr(SCEVAddExpr *S);
103 Value *visitMulExpr(SCEVMulExpr *S);
105 Value *visitUDivExpr(SCEVUDivExpr *S);
107 Value *visitSDivExpr(SCEVSDivExpr *S);
109 Value *visitAddRecExpr(SCEVAddRecExpr *S);
111 Value *visitSMaxExpr(SCEVSMaxExpr *S);
113 Value *visitUMaxExpr(SCEVUMaxExpr *S);
115 Value *visitUnknown(SCEVUnknown *S) {
116 return S->getValue();