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llvm-6502/include/llvm/Analysis/ScalarEvolutionExpander.h
Dan Gohman c40f17b087 Generalize ScalarEvolution to be able to analyze GEPs when
TargetData is not present. It still uses TargetData when available.
This generalization also fixed some limitations in the TargetData
case; the attached testcase covers this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79344 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-18 16:46:41 +00:00

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//===---- llvm/Analysis/ScalarEvolutionExpander.h - SCEV Exprs --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the classes used to generate code from scalar expressions.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Support/IRBuilder.h"
#include "llvm/Support/TargetFolder.h"
#include <set>
namespace llvm {
/// 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
/// memory.
struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
ScalarEvolution &SE;
std::map<std::pair<const SCEV *, Instruction *>, AssertingVH<Value> >
InsertedExpressions;
std::set<Value*> InsertedValues;
typedef IRBuilder<true, TargetFolder> BuilderType;
BuilderType Builder;
friend struct SCEVVisitor<SCEVExpander, Value*>;
public:
explicit SCEVExpander(ScalarEvolution &se)
: SE(se), Builder(se.getContext(),
TargetFolder(se.TD, se.getContext())) {}
/// 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(); }
/// 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);
/// expandCodeFor - Insert code to directly compute the specified SCEV
/// expression into the program. The inserted code is inserted into the
/// specified block.
Value *expandCodeFor(const SCEV *SH, const Type *Ty, Instruction *IP) {
Builder.SetInsertPoint(IP->getParent(), IP);
return expandCodeFor(SH, Ty);
}
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);
/// 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, const 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,
const PointerType *PTy, const 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, const Type *Ty = 0);
/// 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);
}
Value *visitConstant(const SCEVConstant *S) {
return S->getValue();
}
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 *visitUMaxExpr(const SCEVUMaxExpr *S);
Value *visitFieldOffsetExpr(const SCEVFieldOffsetExpr *S);
Value *visitAllocSizeExpr(const SCEVAllocSizeExpr *S);
Value *visitUnknown(const SCEVUnknown *S) {
return S->getValue();
}
};
}
#endif