llvm-6502/include/llvm/Analysis/ScalarEvolutionExpander.h
Dan Gohman 752ec7da50 Change SCEVExpander's expandCodeFor to provide more flexibility
with the persistent insertion point, and change IndVars to make
use of it. This fixes a bug where IndVars was holding on to a
stale insertion point and forcing the SCEVExpander to continue to
use it.

This fixes PR4038.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69892 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-23 15:16:49 +00:00

139 lines
5.0 KiB
C++

//===---- 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/Instructions.h"
#include "llvm/Type.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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;
LoopInfo &LI;
std::map<SCEVHandle, Value*> InsertedExpressions;
std::set<Instruction*> InsertedInstructions;
BasicBlock::iterator InsertPt;
friend struct SCEVVisitor<SCEVExpander, Value*>;
public:
SCEVExpander(ScalarEvolution &se, LoopInfo &li)
: SE(se), LI(li) {}
LoopInfo &getLoopInfo() const { return LI; }
/// 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(); }
/// 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);
}
/// 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() && "Can only insert integer induction variables!");
SCEVHandle H = SE.getAddRecExpr(SE.getIntegerSCEV(0, Ty),
SE.getIntegerSCEV(1, Ty), L);
return expand(H);
}
/// addInsertedValue - Remember the specified instruction as being the
/// canonical form for the specified SCEV.
void addInsertedValue(Instruction *I, const SCEV *S) {
InsertedExpressions[S] = (Value*)I;
InsertedInstructions.insert(I);
}
void setInsertionPoint(BasicBlock::iterator NewIP) { InsertPt = NewIP; }
BasicBlock::iterator getInsertionPoint() const { return InsertPt; }
/// 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.
Value *expandCodeFor(SCEVHandle SH, 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(SCEVHandle SH, const Type *Ty,
BasicBlock::iterator IP) {
setInsertionPoint(IP);
return expandCodeFor(SH, Ty);
}
/// InsertCastOfTo - Insert a cast of V to the specified type, doing what
/// we can to share the casts.
Value *InsertCastOfTo(Instruction::CastOps opcode, Value *V,
const Type *Ty);
/// InsertNoopCastOfTo - Insert a cast of V to the specified type,
/// which must be possible with a noop cast.
Value *InsertNoopCastOfTo(Value *V, const Type *Ty);
/// InsertBinop - Insert the specified binary operator, doing a small amount
/// of work to avoid inserting an obviously redundant operation.
static Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
Value *RHS, BasicBlock::iterator InsertPt);
private:
Value *expand(const SCEV *S);
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 *visitUnknown(const SCEVUnknown *S) {
return S->getValue();
}
};
}
#endif