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 FunctionPass; 26 class Instruction; 27 class AssumptionCache; 28 class DominatorTree; 29 30 /// Build a call to llvm.assume to preserve informations that can be derived 31 /// from the given instruction. 32 /// If no information derived from \p I, this call returns null. 33 /// The returned instruction is not inserted anywhere. 34 AssumeInst *buildAssumeFromInst(Instruction *I); 35 36 /// Calls BuildAssumeFromInst and if the resulting llvm.assume is valid insert 37 /// if before I. This is usually what need to be done to salvage the knowledge 38 /// contained in the instruction I. 39 /// The AssumptionCache must be provided if it is available or the cache may 40 /// become silently be invalid. 41 /// The DominatorTree can optionally be provided to enable cross-block 42 /// reasoning. 43 void 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 FunctionPass *createAssumeSimplifyPass(); 60 61 /// This pass will try to build an llvm.assume for every instruction in the 62 /// function. Its main purpose is testing. 63 struct AssumeBuilderPass : public PassInfoMixin<AssumeBuilderPass> { 64 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); 65 }; 66 67 /// canonicalize the RetainedKnowledge RK. it is assumed that RK is part of 68 /// Assume. This will return an empty RetainedKnowledge if the knowledge is 69 /// useless. 70 RetainedKnowledge simplifyRetainedKnowledge(AssumeInst *Assume, 71 RetainedKnowledge RK, 72 AssumptionCache *AC, 73 DominatorTree *DT); 74 75 } // namespace llvm 76 77 #endif 78