1//===- AssumeBundleBuilder.h - utils to build assume bundles ----*- 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 contain tools to preserve informations. They should be used before
10// performing a transformation that may move and delete instructions as those
11// transformation may destroy or worsen information that can be derived from the
12// IR.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_TRANSFORMS_UTILS_ASSUMEBUNDLEBUILDER_H
17#define LLVM_TRANSFORMS_UTILS_ASSUMEBUNDLEBUILDER_H
18
19#include "llvm/Analysis/AssumeBundleQueries.h"
20#include "llvm/IR/PassManager.h"
21#include "llvm/Support/CommandLine.h"
22
23namespace llvm {
24class AssumeInst;
25class Function;
26class Instruction;
27class AssumptionCache;
28class DominatorTree;
29
30extern cl::opt<bool> EnableKnowledgeRetention;
31
32/// Build a call to llvm.assume to preserve informations that can be derived
33/// from the given instruction.
34/// If no information derived from \p I, this call returns null.
35/// The returned instruction is not inserted anywhere.
36AssumeInst *buildAssumeFromInst(Instruction *I);
37
38/// Calls BuildAssumeFromInst and if the resulting llvm.assume is valid insert
39/// if before I. This is usually what need to be done to salvage the knowledge
40/// contained in the instruction I.
41/// The AssumptionCache must be provided if it is available or the cache may
42/// become silently be invalid.
43/// The DominatorTree can optionally be provided to enable cross-block
44/// reasoning.
45/// This returns if a change was made.
46bool salvageKnowledge(Instruction *I, AssumptionCache *AC = nullptr,
47 DominatorTree *DT = nullptr);
48
49/// Build and return a new assume created from the provided knowledge
50/// if the knowledge in the assume is fully redundant this will return nullptr
51AssumeInst *buildAssumeFromKnowledge(ArrayRef<RetainedKnowledge> Knowledge,
52 Instruction *CtxI,
53 AssumptionCache *AC = nullptr,
54 DominatorTree *DT = nullptr);
55
56/// This pass attempts to minimize the number of assume without loosing any
57/// information.
58struct AssumeSimplifyPass : public PassInfoMixin<AssumeSimplifyPass> {
59 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
60};
61
62/// This pass will try to build an llvm.assume for every instruction in the
63/// function. Its main purpose is testing.
64struct AssumeBuilderPass : public PassInfoMixin<AssumeBuilderPass> {
65 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
66};
67
68/// canonicalize the RetainedKnowledge RK. it is assumed that RK is part of
69/// Assume. This will return an empty RetainedKnowledge if the knowledge is
70/// useless.
71RetainedKnowledge simplifyRetainedKnowledge(AssumeInst *Assume,
72 RetainedKnowledge RK,
73 AssumptionCache *AC,
74 DominatorTree *DT);
75
76} // namespace llvm
77
78#endif
79

source code of llvm/include/llvm/Transforms/Utils/AssumeBundleBuilder.h