1 //===- AssumeBundleQueries.cpp - tool to query 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 #include "llvm/Analysis/AssumeBundleQueries.h" 10 #include "llvm/ADT/Statistic.h" 11 #include "llvm/Analysis/AssumptionCache.h" 12 #include "llvm/Analysis/ValueTracking.h" 13 #include "llvm/IR/Instruction.h" 14 #include "llvm/IR/Instructions.h" 15 #include "llvm/IR/IntrinsicInst.h" 16 #include "llvm/IR/PatternMatch.h" 17 #include "llvm/Support/DebugCounter.h" 18 19 #define DEBUG_TYPE "assume-queries" 20 21 using namespace llvm; 22 using namespace llvm::PatternMatch; 23 24 STATISTIC(NumAssumeQueries, "Number of Queries into an assume assume bundles"); 25 STATISTIC( 26 NumUsefullAssumeQueries, 27 "Number of Queries into an assume assume bundles that were satisfied"); 28 29 DEBUG_COUNTER(AssumeQueryCounter, "assume-queries-counter", 30 "Controls which assumes gets created"); 31 32 static bool bundleHasArgument(const CallBase::BundleOpInfo &BOI, unsigned Idx) { 33 return BOI.End - BOI.Begin > Idx; 34 } 35 36 static Value *getValueFromBundleOpInfo(AssumeInst &Assume, 37 const CallBase::BundleOpInfo &BOI, 38 unsigned Idx) { 39 assert(bundleHasArgument(BOI, Idx) && "index out of range"); 40 return (Assume.op_begin() + BOI.Begin + Idx)->get(); 41 } 42 43 bool llvm::hasAttributeInAssume(AssumeInst &Assume, Value *IsOn, 44 StringRef AttrName, uint64_t *ArgVal) { 45 assert(Attribute::isExistingAttribute(AttrName) && 46 "this attribute doesn't exist"); 47 assert((ArgVal == nullptr || Attribute::isIntAttrKind( 48 Attribute::getAttrKindFromName(AttrName))) && 49 "requested value for an attribute that has no argument"); 50 if (Assume.bundle_op_infos().empty()) 51 return false; 52 53 for (auto &BOI : Assume.bundle_op_infos()) { 54 if (BOI.Tag->getKey() != AttrName) 55 continue; 56 if (IsOn && (BOI.End - BOI.Begin <= ABA_WasOn || 57 IsOn != getValueFromBundleOpInfo(Assume, BOI, ABA_WasOn))) 58 continue; 59 if (ArgVal) { 60 assert(BOI.End - BOI.Begin > ABA_Argument); 61 *ArgVal = 62 cast<ConstantInt>(getValueFromBundleOpInfo(Assume, BOI, ABA_Argument)) 63 ->getZExtValue(); 64 } 65 return true; 66 } 67 return false; 68 } 69 70 void llvm::fillMapFromAssume(AssumeInst &Assume, RetainedKnowledgeMap &Result) { 71 for (auto &Bundles : Assume.bundle_op_infos()) { 72 std::pair<Value *, Attribute::AttrKind> Key{ 73 nullptr, Attribute::getAttrKindFromName(Bundles.Tag->getKey())}; 74 if (bundleHasArgument(Bundles, ABA_WasOn)) 75 Key.first = getValueFromBundleOpInfo(Assume, Bundles, ABA_WasOn); 76 77 if (Key.first == nullptr && Key.second == Attribute::None) 78 continue; 79 if (!bundleHasArgument(Bundles, ABA_Argument)) { 80 Result[Key][&Assume] = {0, 0}; 81 continue; 82 } 83 auto *CI = dyn_cast<ConstantInt>( 84 getValueFromBundleOpInfo(Assume, Bundles, ABA_Argument)); 85 if (!CI) 86 continue; 87 uint64_t Val = CI->getZExtValue(); 88 auto [It, Inserted] = Result[Key].try_emplace(&Assume); 89 if (Inserted) { 90 It->second = {Val, Val}; 91 continue; 92 } 93 auto &MinMax = It->second; 94 MinMax.Min = std::min(Val, MinMax.Min); 95 MinMax.Max = std::max(Val, MinMax.Max); 96 } 97 } 98 99 RetainedKnowledge 100 llvm::getKnowledgeFromBundle(AssumeInst &Assume, 101 const CallBase::BundleOpInfo &BOI) { 102 RetainedKnowledge Result; 103 if (!DebugCounter::shouldExecute(AssumeQueryCounter)) 104 return Result; 105 106 Result.AttrKind = Attribute::getAttrKindFromName(BOI.Tag->getKey()); 107 if (bundleHasArgument(BOI, ABA_WasOn)) 108 Result.WasOn = getValueFromBundleOpInfo(Assume, BOI, ABA_WasOn); 109 auto GetArgOr1 = [&](unsigned Idx) -> uint64_t { 110 if (auto *ConstInt = dyn_cast<ConstantInt>( 111 getValueFromBundleOpInfo(Assume, BOI, ABA_Argument + Idx))) 112 return ConstInt->getZExtValue(); 113 return 1; 114 }; 115 if (BOI.End - BOI.Begin > ABA_Argument) 116 Result.ArgValue = GetArgOr1(0); 117 Result.IRArgValue = bundleHasArgument(BOI, ABA_Argument) 118 ? getValueFromBundleOpInfo(Assume, BOI, ABA_Argument) 119 : nullptr; 120 if (Result.AttrKind == Attribute::Alignment) 121 if (BOI.End - BOI.Begin > ABA_Argument + 1) 122 Result.ArgValue = MinAlign(Result.ArgValue, GetArgOr1(1)); 123 return Result; 124 } 125 126 RetainedKnowledge llvm::getKnowledgeFromOperandInAssume(AssumeInst &Assume, 127 unsigned Idx) { 128 CallBase::BundleOpInfo BOI = Assume.getBundleOpInfoForOperand(Idx); 129 return getKnowledgeFromBundle(Assume, BOI); 130 } 131 132 bool llvm::isAssumeWithEmptyBundle(const AssumeInst &Assume) { 133 return none_of(Assume.bundle_op_infos(), 134 [](const CallBase::BundleOpInfo &BOI) { 135 return BOI.Tag->getKey() != IgnoreBundleTag; 136 }); 137 } 138 139 static CallInst::BundleOpInfo *getBundleFromUse(const Use *U) { 140 if (!match(U->getUser(), 141 m_Intrinsic<Intrinsic::assume>(m_Unless(m_Specific(U->get()))))) 142 return nullptr; 143 auto *Intr = cast<IntrinsicInst>(U->getUser()); 144 return &Intr->getBundleOpInfoForOperand(U->getOperandNo()); 145 } 146 147 RetainedKnowledge 148 llvm::getKnowledgeFromUse(const Use *U, 149 ArrayRef<Attribute::AttrKind> AttrKinds) { 150 CallInst::BundleOpInfo* Bundle = getBundleFromUse(U); 151 if (!Bundle) 152 return RetainedKnowledge::none(); 153 RetainedKnowledge RK = 154 getKnowledgeFromBundle(*cast<AssumeInst>(U->getUser()), *Bundle); 155 if (llvm::is_contained(AttrKinds, RK.AttrKind)) 156 return RK; 157 return RetainedKnowledge::none(); 158 } 159 160 RetainedKnowledge 161 llvm::getKnowledgeForValue(const Value *V, 162 ArrayRef<Attribute::AttrKind> AttrKinds, 163 AssumptionCache &AC, 164 function_ref<bool(RetainedKnowledge, Instruction *, 165 const CallBase::BundleOpInfo *)> 166 Filter) { 167 NumAssumeQueries++; 168 for (AssumptionCache::ResultElem &Elem : AC.assumptionsFor(V)) { 169 auto *II = cast_or_null<AssumeInst>(Elem.Assume); 170 if (!II || Elem.Index == AssumptionCache::ExprResultIdx) 171 continue; 172 if (RetainedKnowledge RK = getKnowledgeFromBundle( 173 *II, II->bundle_op_info_begin()[Elem.Index])) { 174 if (V != RK.WasOn) 175 continue; 176 if (is_contained(AttrKinds, RK.AttrKind) && 177 Filter(RK, II, &II->bundle_op_info_begin()[Elem.Index])) { 178 NumUsefullAssumeQueries++; 179 return RK; 180 } 181 } 182 } 183 184 return RetainedKnowledge::none(); 185 } 186 187 RetainedKnowledge llvm::getKnowledgeValidInContext( 188 const Value *V, ArrayRef<Attribute::AttrKind> AttrKinds, 189 AssumptionCache &AC, const Instruction *CtxI, const DominatorTree *DT) { 190 return getKnowledgeForValue(V, AttrKinds, AC, 191 [&](auto, Instruction *I, auto) { 192 return isValidAssumeForContext(I, CtxI, DT); 193 }); 194 } 195