llvm-6502/include/llvm/Analysis/LoopVR.h

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//===- LoopVR.cpp - Value Range analysis driven by loop information -------===//
//
// 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 interface for the loop-driven value range pass.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LOOPVR_H
#define LLVM_ANALYSIS_LOOPVR_H
#include "llvm/Pass.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Support/ConstantRange.h"
#include <iosfwd>
#include <map>
namespace llvm {
/// LoopVR - This class maintains a mapping of Values to ConstantRanges.
/// There are interfaces to look up and update ranges by value, and for
/// accessing all values with range information.
///
class LoopVR : public FunctionPass {
public:
static char ID; // Class identification, replacement for typeinfo
LoopVR() : FunctionPass(&ID) {}
bool runOnFunction(Function &F);
virtual void print(std::ostream &os, const Module *) const;
void releaseMemory();
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequiredTransitive<LoopInfo>();
AU.addRequiredTransitive<ScalarEvolution>();
AU.setPreservesAll();
}
//===---------------------------------------------------------------------
// Methods that are used to look up and update particular values.
/// get - return the ConstantRange for a given Value of IntegerType.
ConstantRange get(Value *V);
/// remove - remove a value from this analysis.
void remove(Value *V);
/// narrow - improve our unterstanding of a Value by pointing out that it
/// must fall within ConstantRange. To replace a range, remove it first.
void narrow(Value *V, const ConstantRange &CR);
//===---------------------------------------------------------------------
// Methods that are used to iterate across all values with information.
/// size - returns the number of Values with information
unsigned size() const { return Map.size(); }
typedef std::map<Value *, ConstantRange *>::iterator iterator;
/// begin - return an iterator to the first Value, ConstantRange pair
iterator begin() { return Map.begin(); }
/// end - return an iterator one past the last Value, ConstantRange pair
iterator end() { return Map.end(); }
/// getValue - return the Value referenced by an iterator
Value *getValue(iterator I) { return I->first; }
/// getConstantRange - return the ConstantRange referenced by an iterator
ConstantRange getConstantRange(iterator I) { return *I->second; }
private:
ConstantRange compute(Value *V);
ConstantRange getRange(const SCEV* S, Loop *L, ScalarEvolution &SE);
ConstantRange getRange(const SCEV* S, const SCEV* T, ScalarEvolution &SE);
std::map<Value *, ConstantRange *> Map;
};
} // end llvm namespace
#endif