[Alignment][NFC] Support compile time constants
[llvm-core.git] / include / llvm / Analysis / PHITransAddr.h
blob54a07f05347877950a2aa09ef185e551f485a5d6
1 //===- PHITransAddr.h - PHI Translation for Addresses -----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file declares the PHITransAddr class.
11 //===----------------------------------------------------------------------===//
13 #ifndef LLVM_ANALYSIS_PHITRANSADDR_H
14 #define LLVM_ANALYSIS_PHITRANSADDR_H
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/IR/Instruction.h"
19 namespace llvm {
20 class AssumptionCache;
21 class DominatorTree;
22 class DataLayout;
23 class TargetLibraryInfo;
25 /// PHITransAddr - An address value which tracks and handles phi translation.
26 /// As we walk "up" the CFG through predecessors, we need to ensure that the
27 /// address we're tracking is kept up to date. For example, if we're analyzing
28 /// an address of "&A[i]" and walk through the definition of 'i' which is a PHI
29 /// node, we *must* phi translate i to get "&A[j]" or else we will analyze an
30 /// incorrect pointer in the predecessor block.
31 ///
32 /// This is designed to be a relatively small object that lives on the stack and
33 /// is copyable.
34 ///
35 class PHITransAddr {
36 /// Addr - The actual address we're analyzing.
37 Value *Addr;
39 /// The DataLayout we are playing with.
40 const DataLayout &DL;
42 /// TLI - The target library info if known, otherwise null.
43 const TargetLibraryInfo *TLI;
45 /// A cache of \@llvm.assume calls used by SimplifyInstruction.
46 AssumptionCache *AC;
48 /// InstInputs - The inputs for our symbolic address.
49 SmallVector<Instruction*, 4> InstInputs;
51 public:
52 PHITransAddr(Value *addr, const DataLayout &DL, AssumptionCache *AC)
53 : Addr(addr), DL(DL), TLI(nullptr), AC(AC) {
54 // If the address is an instruction, the whole thing is considered an input.
55 if (Instruction *I = dyn_cast<Instruction>(Addr))
56 InstInputs.push_back(I);
59 Value *getAddr() const { return Addr; }
61 /// NeedsPHITranslationFromBlock - Return true if moving from the specified
62 /// BasicBlock to its predecessors requires PHI translation.
63 bool NeedsPHITranslationFromBlock(BasicBlock *BB) const {
64 // We do need translation if one of our input instructions is defined in
65 // this block.
66 for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
67 if (InstInputs[i]->getParent() == BB)
68 return true;
69 return false;
72 /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
73 /// if we have some hope of doing it. This should be used as a filter to
74 /// avoid calling PHITranslateValue in hopeless situations.
75 bool IsPotentiallyPHITranslatable() const;
77 /// PHITranslateValue - PHI translate the current address up the CFG from
78 /// CurBB to Pred, updating our state to reflect any needed changes. If
79 /// 'MustDominate' is true, the translated value must dominate
80 /// PredBB. This returns true on failure and sets Addr to null.
81 bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB,
82 const DominatorTree *DT, bool MustDominate);
84 /// PHITranslateWithInsertion - PHI translate this value into the specified
85 /// predecessor block, inserting a computation of the value if it is
86 /// unavailable.
87 ///
88 /// All newly created instructions are added to the NewInsts list. This
89 /// returns null on failure.
90 ///
91 Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
92 const DominatorTree &DT,
93 SmallVectorImpl<Instruction *> &NewInsts);
95 void dump() const;
97 /// Verify - Check internal consistency of this data structure. If the
98 /// structure is valid, it returns true. If invalid, it prints errors and
99 /// returns false.
100 bool Verify() const;
102 private:
103 Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB,
104 const DominatorTree *DT);
106 /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated
107 /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
108 /// block. All newly created instructions are added to the NewInsts list.
109 /// This returns null on failure.
111 Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
112 BasicBlock *PredBB, const DominatorTree &DT,
113 SmallVectorImpl<Instruction *> &NewInsts);
115 /// AddAsInput - If the specified value is an instruction, add it as an input.
116 Value *AddAsInput(Value *V) {
117 // If V is an instruction, it is now an input.
118 if (Instruction *VI = dyn_cast<Instruction>(V))
119 InstInputs.push_back(VI);
120 return V;
124 } // end namespace llvm
126 #endif