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"
23 class TargetLibraryInfo;
26 /// LazyValueInfo - This pass computes, caches, and vends lazy value constraint
28 class LazyValueInfo : public FunctionPass {
30 class TargetLibraryInfo *TLI;
32 LazyValueInfo(const LazyValueInfo&) LLVM_DELETED_FUNCTION;
33 void operator=(const LazyValueInfo&) LLVM_DELETED_FUNCTION;
36 LazyValueInfo() : FunctionPass(ID), PImpl(nullptr) {
37 initializeLazyValueInfoPass(*PassRegistry::getPassRegistry());
39 ~LazyValueInfo() { assert(!PImpl && "releaseMemory not called"); }
41 /// Tristate - This is used to return true/false/dunno results.
43 Unknown = -1, False = 0, True = 1
47 // Public query interface.
49 /// getPredicateOnEdge - Determine whether the specified value comparison
50 /// with a constant is known to be true or false on the specified CFG edge.
51 /// Pred is a CmpInst predicate.
52 Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
53 BasicBlock *FromBB, BasicBlock *ToBB);
56 /// getConstant - Determine whether the specified value is known to be a
57 /// constant at the end of the specified block. Return null if not.
58 Constant *getConstant(Value *V, BasicBlock *BB);
60 /// getConstantOnEdge - Determine whether the specified value is known to be a
61 /// constant on the specified edge. Return null if not.
62 Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB);
64 /// threadEdge - Inform the analysis cache that we have threaded an edge from
65 /// PredBB to OldSucc to be from PredBB to NewSucc instead.
66 void threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, BasicBlock *NewSucc);
68 /// eraseBlock - Inform the analysis cache that we have erased a block.
69 void eraseBlock(BasicBlock *BB);
71 // Implementation boilerplate.
73 void getAnalysisUsage(AnalysisUsage &AU) const override;
74 void releaseMemory() override;
75 bool runOnFunction(Function &F) override;
78 } // end namespace llvm