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