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/Analysis/ScalarEvolutionExpressions.h"
18 #include "llvm/Support/IRBuilder.h"
19 #include "llvm/Support/TargetFolder.h"
22 /// SCEVExpander - This class uses information about analyze scalars to
23 /// rewrite expressions in canonical form.
25 /// Clients should create an instance of this class when rewriting is needed,
26 /// and destroy it when finished to allow the release of the associated
28 struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
30 std::map<std::pair<const SCEV *, Instruction *>, AssertingVH<Value> >
32 std::set<Value*> InsertedValues;
34 typedef IRBuilder<true, TargetFolder> BuilderType;
37 friend struct SCEVVisitor<SCEVExpander, Value*>;
39 explicit SCEVExpander(ScalarEvolution &se)
40 : SE(se), Builder(*se.getContext(),
41 TargetFolder(se.TD, *se.getContext())) {}
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 /// getOrInsertCanonicalInductionVariable - This method returns the
49 /// canonical induction variable of the specified type for the specified
50 /// loop (inserting one if there is none). A canonical induction variable
51 /// starts at zero and steps by one on each iteration.
52 Value *getOrInsertCanonicalInductionVariable(const Loop *L, const Type *Ty);
54 /// expandCodeFor - Insert code to directly compute the specified SCEV
55 /// expression into the program. The inserted code is inserted into the
57 Value *expandCodeFor(const SCEV *SH, const Type *Ty, Instruction *IP) {
58 Builder.SetInsertPoint(IP->getParent(), IP);
59 return expandCodeFor(SH, Ty);
63 LLVMContext *getContext() const { return SE.getContext(); }
65 /// InsertBinop - Insert the specified binary operator, doing a small amount
66 /// of work to avoid inserting an obviously redundant operation.
67 Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS);
69 /// InsertNoopCastOfTo - Insert a cast of V to the specified type,
70 /// which must be possible with a noop cast, doing what we can to
72 Value *InsertNoopCastOfTo(Value *V, const Type *Ty);
74 /// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP
75 /// instead of using ptrtoint+arithmetic+inttoptr.
76 Value *expandAddToGEP(const SCEV *const *op_begin,
77 const SCEV *const *op_end,
78 const PointerType *PTy, const Type *Ty, Value *V);
80 Value *expand(const SCEV *S);
82 /// expandCodeFor - Insert code to directly compute the specified SCEV
83 /// expression into the program. The inserted code is inserted into the
84 /// SCEVExpander's current insertion point. If a type is specified, the
85 /// result will be expanded to have that type, with a cast if necessary.
86 Value *expandCodeFor(const SCEV *SH, const Type *Ty = 0);
88 /// isInsertedInstruction - Return true if the specified instruction was
89 /// inserted by the code rewriter. If so, the client should not modify the
91 bool isInsertedInstruction(Instruction *I) const {
92 return InsertedValues.count(I);
95 Value *visitConstant(const SCEVConstant *S) {
99 Value *visitTruncateExpr(const SCEVTruncateExpr *S);
101 Value *visitZeroExtendExpr(const SCEVZeroExtendExpr *S);
103 Value *visitSignExtendExpr(const SCEVSignExtendExpr *S);
105 Value *visitAddExpr(const SCEVAddExpr *S);
107 Value *visitMulExpr(const SCEVMulExpr *S);
109 Value *visitUDivExpr(const SCEVUDivExpr *S);
111 Value *visitAddRecExpr(const SCEVAddRecExpr *S);
113 Value *visitSMaxExpr(const SCEVSMaxExpr *S);
115 Value *visitUMaxExpr(const SCEVUMaxExpr *S);
117 Value *visitUnknown(const SCEVUnknown *S) {
118 return S->getValue();