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/Attributes.h" 21 #include "llvm/IR/Instruction.h" 22 #include "llvm/IR/PassManager.h" 23 24 namespace llvm { 25 class AssumptionCache; 26 class DominatorTree; 27 28 /// Build a call to llvm.assume to preserve informations that can be derived 29 /// from the given instruction. 30 /// If no information derived from \p I, this call returns null. 31 /// The returned instruction is not inserted anywhere. 32 AssumeInst *buildAssumeFromInst(Instruction *I); 33 34 /// Calls BuildAssumeFromInst and if the resulting llvm.assume is valid insert 35 /// if before I. This is usually what need to be done to salvage the knowledge 36 /// contained in the instruction I. 37 /// The AssumptionCache must be provided if it is available or the cache may 38 /// become silently be invalid. 39 /// The DominatorTree can optionally be provided to enable cross-block 40 /// reasoning. 41 void salvageKnowledge(Instruction *I, AssumptionCache *AC = nullptr, 42 DominatorTree *DT = nullptr); 43 44 /// Build and return a new assume created from the provided knowledge 45 /// if the knowledge in the assume is fully redundant this will return nullptr 46 AssumeInst *buildAssumeFromKnowledge(ArrayRef<RetainedKnowledge> Knowledge, 47 Instruction *CtxI, 48 AssumptionCache *AC = nullptr, 49 DominatorTree *DT = nullptr); 50 51 /// This pass attempts to minimize the number of assume without loosing any 52 /// information. 53 struct AssumeSimplifyPass : public PassInfoMixin<AssumeSimplifyPass> { 54 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); 55 }; 56 57 FunctionPass *createAssumeSimplifyPass(); 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