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llvm-mirror/include/llvm/Analysis/LazyValueInfo.h
John Regehr b357c876ed [LVI] Add an API to LazyValueInfo so that it can export ConstantRanges
that it computes. Currently this is used for testing and precision
tuning, but it might be used by optimizations later.

Differential Revision: http://reviews.llvm.org/D19179

llvm-svn: 268291
2016-05-02 19:58:00 +00:00

97 lines
3.4 KiB
C++

//===- LazyValueInfo.h - Value constraint analysis --------------*- 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 interface for lazy computation of value constraint
// information.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LAZYVALUEINFO_H
#define LLVM_ANALYSIS_LAZYVALUEINFO_H
#include "llvm/Pass.h"
namespace llvm {
class AssumptionCache;
class Constant;
class ConstantRange;
class DataLayout;
class DominatorTree;
class Instruction;
class TargetLibraryInfo;
class Value;
/// This pass computes, caches, and vends lazy value constraint information.
class LazyValueInfo : public FunctionPass {
AssumptionCache *AC;
class TargetLibraryInfo *TLI;
DominatorTree *DT;
void *PImpl;
LazyValueInfo(const LazyValueInfo&) = delete;
void operator=(const LazyValueInfo&) = delete;
public:
static char ID;
LazyValueInfo() : FunctionPass(ID), PImpl(nullptr) {
initializeLazyValueInfoPass(*PassRegistry::getPassRegistry());
}
~LazyValueInfo() override { assert(!PImpl && "releaseMemory not called"); }
/// This is used to return true/false/dunno results.
enum Tristate {
Unknown = -1, False = 0, True = 1
};
// Public query interface.
/// Determine whether the specified value comparison with a constant is known
/// to be true or false on the specified CFG edge.
/// Pred is a CmpInst predicate.
Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
BasicBlock *FromBB, BasicBlock *ToBB,
Instruction *CxtI = nullptr);
/// Determine whether the specified value comparison with a constant is known
/// to be true or false at the specified instruction
/// (from an assume intrinsic). Pred is a CmpInst predicate.
Tristate getPredicateAt(unsigned Pred, Value *V, Constant *C,
Instruction *CxtI);
/// Determine whether the specified value is known to be a
/// constant at the end of the specified block. Return null if not.
Constant *getConstant(Value *V, BasicBlock *BB, Instruction *CxtI = nullptr);
/// Return the ConstantRange constraint that is known to hold for the
/// specified value at the end of the specified block. This may only be called
/// on integer-typed Values.
ConstantRange getConstantRange(Value *V, BasicBlock *BB, Instruction *CxtI = nullptr);
/// Determine whether the specified value is known to be a
/// constant on the specified edge. Return null if not.
Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
Instruction *CxtI = nullptr);
/// Inform the analysis cache that we have threaded an edge from
/// PredBB to OldSucc to be from PredBB to NewSucc instead.
void threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, BasicBlock *NewSucc);
/// Inform the analysis cache that we have erased a block.
void eraseBlock(BasicBlock *BB);
// Implementation boilerplate.
void getAnalysisUsage(AnalysisUsage &AU) const override;
void releaseMemory() override;
bool runOnFunction(Function &F) override;
};
} // end namespace llvm
#endif