1 //===- LazyValueInfo.h - Value constraint analysis --------------*- 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 interface for lazy computation of value constraint
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_LAZYVALUEINFO_H
16 #define LLVM_ANALYSIS_LAZYVALUEINFO_H
18 #include "llvm/Pass.h"
25 /// LazyValueInfo - This pass computes, caches, and vends lazy value constraint
27 class LazyValueInfo : public FunctionPass {
30 LazyValueInfo(const LazyValueInfo&); // DO NOT IMPLEMENT.
31 void operator=(const LazyValueInfo&); // DO NOT IMPLEMENT.
34 LazyValueInfo() : FunctionPass(ID), PImpl(0) {
35 initializeLazyValueInfoPass(*PassRegistry::getPassRegistry());
37 ~LazyValueInfo() { assert(PImpl == 0 && "releaseMemory not called"); }
39 /// Tristate - This is used to return true/false/dunno results.
41 Unknown = -1, False = 0, True = 1
45 // Public query interface.
47 /// getPredicateOnEdge - Determine whether the specified value comparison
48 /// with a constant is known to be true or false on the specified CFG edge.
49 /// Pred is a CmpInst predicate.
50 Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
51 BasicBlock *FromBB, BasicBlock *ToBB);
54 /// getConstant - Determine whether the specified value is known to be a
55 /// constant at the end of the specified block. Return null if not.
56 Constant *getConstant(Value *V, BasicBlock *BB);
58 /// getConstantOnEdge - Determine whether the specified value is known to be a
59 /// constant on the specified edge. Return null if not.
60 Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB);
62 /// threadEdge - Inform the analysis cache that we have threaded an edge from
63 /// PredBB to OldSucc to be from PredBB to NewSucc instead.
64 void threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, BasicBlock *NewSucc);
66 /// eraseBlock - Inform the analysis cache that we have erased a block.
67 void eraseBlock(BasicBlock *BB);
69 // Implementation boilerplate.
71 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
74 virtual void releaseMemory();
75 virtual bool runOnFunction(Function &F);
78 } // end namespace llvm