Bug Summary

File:llvm/lib/Transforms/Scalar/LICM.cpp
Warning:line 1216, column 41
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name LICM.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -mframe-pointer=none -fmath-errno -fno-rounding-math -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -dwarf-column-info -fno-split-dwarf-inlining -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/build-llvm/lib/Transforms/Scalar -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/build-llvm/include -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/build-llvm/lib/Transforms/Scalar -fdebug-prefix-map=/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2020-01-13-084841-49055-1 -x c++ /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp

/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp

1//===-- LICM.cpp - Loop Invariant Code Motion Pass ------------------------===//
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 pass performs loop invariant code motion, attempting to remove as much
10// code from the body of a loop as possible. It does this by either hoisting
11// code into the preheader block, or by sinking code to the exit blocks if it is
12// safe. This pass also promotes must-aliased memory locations in the loop to
13// live in registers, thus hoisting and sinking "invariant" loads and stores.
14//
15// This pass uses alias analysis for two purposes:
16//
17// 1. Moving loop invariant loads and calls out of loops. If we can determine
18// that a load or call inside of a loop never aliases anything stored to,
19// we can hoist it or sink it like any other instruction.
20// 2. Scalar Promotion of Memory - If there is a store instruction inside of
21// the loop, we try to move the store to happen AFTER the loop instead of
22// inside of the loop. This can only happen if a few conditions are true:
23// A. The pointer stored through is loop invariant
24// B. There are no stores or loads in the loop which _may_ alias the
25// pointer. There are no calls in the loop which mod/ref the pointer.
26// If these conditions are true, we can promote the loads and stores in the
27// loop of the pointer to use a temporary alloca'd variable. We then use
28// the SSAUpdater to construct the appropriate SSA form for the value.
29//
30//===----------------------------------------------------------------------===//
31
32#include "llvm/Transforms/Scalar/LICM.h"
33#include "llvm/ADT/SetOperations.h"
34#include "llvm/ADT/Statistic.h"
35#include "llvm/Analysis/AliasAnalysis.h"
36#include "llvm/Analysis/AliasSetTracker.h"
37#include "llvm/Analysis/BasicAliasAnalysis.h"
38#include "llvm/Analysis/CaptureTracking.h"
39#include "llvm/Analysis/ConstantFolding.h"
40#include "llvm/Analysis/GlobalsModRef.h"
41#include "llvm/Analysis/GuardUtils.h"
42#include "llvm/Analysis/Loads.h"
43#include "llvm/Analysis/LoopInfo.h"
44#include "llvm/Analysis/LoopIterator.h"
45#include "llvm/Analysis/LoopPass.h"
46#include "llvm/Analysis/MemoryBuiltins.h"
47#include "llvm/Analysis/MemorySSA.h"
48#include "llvm/Analysis/MemorySSAUpdater.h"
49#include "llvm/Analysis/OptimizationRemarkEmitter.h"
50#include "llvm/Analysis/ScalarEvolution.h"
51#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
52#include "llvm/Analysis/TargetLibraryInfo.h"
53#include "llvm/Analysis/ValueTracking.h"
54#include "llvm/IR/CFG.h"
55#include "llvm/IR/Constants.h"
56#include "llvm/IR/DataLayout.h"
57#include "llvm/IR/DebugInfoMetadata.h"
58#include "llvm/IR/DerivedTypes.h"
59#include "llvm/IR/Dominators.h"
60#include "llvm/IR/Instructions.h"
61#include "llvm/IR/IntrinsicInst.h"
62#include "llvm/IR/LLVMContext.h"
63#include "llvm/IR/Metadata.h"
64#include "llvm/IR/PatternMatch.h"
65#include "llvm/IR/PredIteratorCache.h"
66#include "llvm/InitializePasses.h"
67#include "llvm/Support/CommandLine.h"
68#include "llvm/Support/Debug.h"
69#include "llvm/Support/raw_ostream.h"
70#include "llvm/Transforms/Scalar.h"
71#include "llvm/Transforms/Scalar/LoopPassManager.h"
72#include "llvm/Transforms/Utils/BasicBlockUtils.h"
73#include "llvm/Transforms/Utils/Local.h"
74#include "llvm/Transforms/Utils/LoopUtils.h"
75#include "llvm/Transforms/Utils/SSAUpdater.h"
76#include <algorithm>
77#include <utility>
78using namespace llvm;
79
80#define DEBUG_TYPE"licm" "licm"
81
82STATISTIC(NumCreatedBlocks, "Number of blocks created")static llvm::Statistic NumCreatedBlocks = {"licm", "NumCreatedBlocks"
, "Number of blocks created"}
;
83STATISTIC(NumClonedBranches, "Number of branches cloned")static llvm::Statistic NumClonedBranches = {"licm", "NumClonedBranches"
, "Number of branches cloned"}
;
84STATISTIC(NumSunk, "Number of instructions sunk out of loop")static llvm::Statistic NumSunk = {"licm", "NumSunk", "Number of instructions sunk out of loop"
}
;
85STATISTIC(NumHoisted, "Number of instructions hoisted out of loop")static llvm::Statistic NumHoisted = {"licm", "NumHoisted", "Number of instructions hoisted out of loop"
}
;
86STATISTIC(NumMovedLoads, "Number of load insts hoisted or sunk")static llvm::Statistic NumMovedLoads = {"licm", "NumMovedLoads"
, "Number of load insts hoisted or sunk"}
;
87STATISTIC(NumMovedCalls, "Number of call insts hoisted or sunk")static llvm::Statistic NumMovedCalls = {"licm", "NumMovedCalls"
, "Number of call insts hoisted or sunk"}
;
88STATISTIC(NumPromoted, "Number of memory locations promoted to registers")static llvm::Statistic NumPromoted = {"licm", "NumPromoted", "Number of memory locations promoted to registers"
}
;
89
90/// Memory promotion is enabled by default.
91static cl::opt<bool>
92 DisablePromotion("disable-licm-promotion", cl::Hidden, cl::init(false),
93 cl::desc("Disable memory promotion in LICM pass"));
94
95static cl::opt<bool> ControlFlowHoisting(
96 "licm-control-flow-hoisting", cl::Hidden, cl::init(false),
97 cl::desc("Enable control flow (and PHI) hoisting in LICM"));
98
99static cl::opt<uint32_t> MaxNumUsesTraversed(
100 "licm-max-num-uses-traversed", cl::Hidden, cl::init(8),
101 cl::desc("Max num uses visited for identifying load "
102 "invariance in loop using invariant start (default = 8)"));
103
104// Default value of zero implies we use the regular alias set tracker mechanism
105// instead of the cross product using AA to identify aliasing of the memory
106// location we are interested in.
107static cl::opt<int>
108LICMN2Theshold("licm-n2-threshold", cl::Hidden, cl::init(0),
109 cl::desc("How many instruction to cross product using AA"));
110
111// Experimental option to allow imprecision in LICM in pathological cases, in
112// exchange for faster compile. This is to be removed if MemorySSA starts to
113// address the same issue. This flag applies only when LICM uses MemorySSA
114// instead on AliasSetTracker. LICM calls MemorySSAWalker's
115// getClobberingMemoryAccess, up to the value of the Cap, getting perfect
116// accuracy. Afterwards, LICM will call into MemorySSA's getDefiningAccess,
117// which may not be precise, since optimizeUses is capped. The result is
118// correct, but we may not get as "far up" as possible to get which access is
119// clobbering the one queried.
120cl::opt<unsigned> llvm::SetLicmMssaOptCap(
121 "licm-mssa-optimization-cap", cl::init(100), cl::Hidden,
122 cl::desc("Enable imprecision in LICM in pathological cases, in exchange "
123 "for faster compile. Caps the MemorySSA clobbering calls."));
124
125// Experimentally, memory promotion carries less importance than sinking and
126// hoisting. Limit when we do promotion when using MemorySSA, in order to save
127// compile time.
128cl::opt<unsigned> llvm::SetLicmMssaNoAccForPromotionCap(
129 "licm-mssa-max-acc-promotion", cl::init(250), cl::Hidden,
130 cl::desc("[LICM & MemorySSA] When MSSA in LICM is disabled, this has no "
131 "effect. When MSSA in LICM is enabled, then this is the maximum "
132 "number of accesses allowed to be present in a loop in order to "
133 "enable memory promotion."));
134
135static bool inSubLoop(BasicBlock *BB, Loop *CurLoop, LoopInfo *LI);
136static bool isNotUsedOrFreeInLoop(const Instruction &I, const Loop *CurLoop,
137 const LoopSafetyInfo *SafetyInfo,
138 TargetTransformInfo *TTI, bool &FreeInLoop);
139static void hoist(Instruction &I, const DominatorTree *DT, const Loop *CurLoop,
140 BasicBlock *Dest, ICFLoopSafetyInfo *SafetyInfo,
141 MemorySSAUpdater *MSSAU, ScalarEvolution *SE,
142 OptimizationRemarkEmitter *ORE);
143static bool sink(Instruction &I, LoopInfo *LI, DominatorTree *DT,
144 const Loop *CurLoop, ICFLoopSafetyInfo *SafetyInfo,
145 MemorySSAUpdater *MSSAU, OptimizationRemarkEmitter *ORE);
146static bool isSafeToExecuteUnconditionally(Instruction &Inst,
147 const DominatorTree *DT,
148 const Loop *CurLoop,
149 const LoopSafetyInfo *SafetyInfo,
150 OptimizationRemarkEmitter *ORE,
151 const Instruction *CtxI = nullptr);
152static bool pointerInvalidatedByLoop(MemoryLocation MemLoc,
153 AliasSetTracker *CurAST, Loop *CurLoop,
154 AliasAnalysis *AA);
155static bool pointerInvalidatedByLoopWithMSSA(MemorySSA *MSSA, MemoryUse *MU,
156 Loop *CurLoop,
157 SinkAndHoistLICMFlags &Flags);
158static Instruction *CloneInstructionInExitBlock(
159 Instruction &I, BasicBlock &ExitBlock, PHINode &PN, const LoopInfo *LI,
160 const LoopSafetyInfo *SafetyInfo, MemorySSAUpdater *MSSAU);
161
162static void eraseInstruction(Instruction &I, ICFLoopSafetyInfo &SafetyInfo,
163 AliasSetTracker *AST, MemorySSAUpdater *MSSAU);
164
165static void moveInstructionBefore(Instruction &I, Instruction &Dest,
166 ICFLoopSafetyInfo &SafetyInfo,
167 MemorySSAUpdater *MSSAU, ScalarEvolution *SE);
168
169namespace {
170struct LoopInvariantCodeMotion {
171 using ASTrackerMapTy = DenseMap<Loop *, std::unique_ptr<AliasSetTracker>>;
172 bool runOnLoop(Loop *L, AliasAnalysis *AA, LoopInfo *LI, DominatorTree *DT,
173 TargetLibraryInfo *TLI, TargetTransformInfo *TTI,
174 ScalarEvolution *SE, MemorySSA *MSSA,
175 OptimizationRemarkEmitter *ORE, bool DeleteAST);
176
177 ASTrackerMapTy &getLoopToAliasSetMap() { return LoopToAliasSetMap; }
178 LoopInvariantCodeMotion(unsigned LicmMssaOptCap,
179 unsigned LicmMssaNoAccForPromotionCap)
180 : LicmMssaOptCap(LicmMssaOptCap),
181 LicmMssaNoAccForPromotionCap(LicmMssaNoAccForPromotionCap) {}
182
183private:
184 ASTrackerMapTy LoopToAliasSetMap;
185 unsigned LicmMssaOptCap;
186 unsigned LicmMssaNoAccForPromotionCap;
187
188 std::unique_ptr<AliasSetTracker>
189 collectAliasInfoForLoop(Loop *L, LoopInfo *LI, AliasAnalysis *AA);
190 std::unique_ptr<AliasSetTracker>
191 collectAliasInfoForLoopWithMSSA(Loop *L, AliasAnalysis *AA,
192 MemorySSAUpdater *MSSAU);
193};
194
195struct LegacyLICMPass : public LoopPass {
196 static char ID; // Pass identification, replacement for typeid
197 LegacyLICMPass(
198 unsigned LicmMssaOptCap = SetLicmMssaOptCap,
199 unsigned LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap)
200 : LoopPass(ID), LICM(LicmMssaOptCap, LicmMssaNoAccForPromotionCap) {
201 initializeLegacyLICMPassPass(*PassRegistry::getPassRegistry());
202 }
203
204 bool runOnLoop(Loop *L, LPPassManager &LPM) override {
205 if (skipLoop(L)) {
206 // If we have run LICM on a previous loop but now we are skipping
207 // (because we've hit the opt-bisect limit), we need to clear the
208 // loop alias information.
209 LICM.getLoopToAliasSetMap().clear();
210 return false;
211 }
212
213 auto *SE = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>();
214 MemorySSA *MSSA = EnableMSSALoopDependency
215 ? (&getAnalysis<MemorySSAWrapperPass>().getMSSA())
216 : nullptr;
217 // For the old PM, we can't use OptimizationRemarkEmitter as an analysis
218 // pass. Function analyses need to be preserved across loop transformations
219 // but ORE cannot be preserved (see comment before the pass definition).
220 OptimizationRemarkEmitter ORE(L->getHeader()->getParent());
221 return LICM.runOnLoop(L,
222 &getAnalysis<AAResultsWrapperPass>().getAAResults(),
223 &getAnalysis<LoopInfoWrapperPass>().getLoopInfo(),
224 &getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
225 &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(
226 *L->getHeader()->getParent()),
227 &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(
228 *L->getHeader()->getParent()),
229 SE ? &SE->getSE() : nullptr, MSSA, &ORE, false);
230 }
231
232 /// This transformation requires natural loop information & requires that
233 /// loop preheaders be inserted into the CFG...
234 ///
235 void getAnalysisUsage(AnalysisUsage &AU) const override {
236 AU.addPreserved<DominatorTreeWrapperPass>();
237 AU.addPreserved<LoopInfoWrapperPass>();
238 AU.addRequired<TargetLibraryInfoWrapperPass>();
239 if (EnableMSSALoopDependency) {
240 AU.addRequired<MemorySSAWrapperPass>();
241 AU.addPreserved<MemorySSAWrapperPass>();
242 }
243 AU.addRequired<TargetTransformInfoWrapperPass>();
244 getLoopAnalysisUsage(AU);
245 }
246
247 using llvm::Pass::doFinalization;
248
249 bool doFinalization() override {
250 auto &AliasSetMap = LICM.getLoopToAliasSetMap();
251 // All loops in the AliasSetMap should be cleaned up already. The only case
252 // where we fail to do so is if an outer loop gets deleted before LICM
253 // visits it.
254 assert(all_of(AliasSetMap,((all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy
::value_type &KV) { return !KV.first->getParentLoop();
}) && "Didn't free loop alias sets") ? static_cast<
void> (0) : __assert_fail ("all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy::value_type &KV) { return !KV.first->getParentLoop(); }) && \"Didn't free loop alias sets\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 258, __PRETTY_FUNCTION__))
255 [](LoopInvariantCodeMotion::ASTrackerMapTy::value_type &KV) {((all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy
::value_type &KV) { return !KV.first->getParentLoop();
}) && "Didn't free loop alias sets") ? static_cast<
void> (0) : __assert_fail ("all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy::value_type &KV) { return !KV.first->getParentLoop(); }) && \"Didn't free loop alias sets\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 258, __PRETTY_FUNCTION__))
256 return !KV.first->getParentLoop();((all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy
::value_type &KV) { return !KV.first->getParentLoop();
}) && "Didn't free loop alias sets") ? static_cast<
void> (0) : __assert_fail ("all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy::value_type &KV) { return !KV.first->getParentLoop(); }) && \"Didn't free loop alias sets\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 258, __PRETTY_FUNCTION__))
257 }) &&((all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy
::value_type &KV) { return !KV.first->getParentLoop();
}) && "Didn't free loop alias sets") ? static_cast<
void> (0) : __assert_fail ("all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy::value_type &KV) { return !KV.first->getParentLoop(); }) && \"Didn't free loop alias sets\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 258, __PRETTY_FUNCTION__))
258 "Didn't free loop alias sets")((all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy
::value_type &KV) { return !KV.first->getParentLoop();
}) && "Didn't free loop alias sets") ? static_cast<
void> (0) : __assert_fail ("all_of(AliasSetMap, [](LoopInvariantCodeMotion::ASTrackerMapTy::value_type &KV) { return !KV.first->getParentLoop(); }) && \"Didn't free loop alias sets\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 258, __PRETTY_FUNCTION__))
;
259 AliasSetMap.clear();
260 return false;
261 }
262
263private:
264 LoopInvariantCodeMotion LICM;
265
266 /// cloneBasicBlockAnalysis - Simple Analysis hook. Clone alias set info.
267 void cloneBasicBlockAnalysis(BasicBlock *From, BasicBlock *To,
268 Loop *L) override;
269
270 /// deleteAnalysisValue - Simple Analysis hook. Delete value V from alias
271 /// set.
272 void deleteAnalysisValue(Value *V, Loop *L) override;
273
274 /// Simple Analysis hook. Delete loop L from alias set map.
275 void deleteAnalysisLoop(Loop *L) override;
276};
277} // namespace
278
279PreservedAnalyses LICMPass::run(Loop &L, LoopAnalysisManager &AM,
280 LoopStandardAnalysisResults &AR, LPMUpdater &) {
281 const auto &FAM =
282 AM.getResult<FunctionAnalysisManagerLoopProxy>(L, AR).getManager();
283 Function *F = L.getHeader()->getParent();
284
285 auto *ORE = FAM.getCachedResult<OptimizationRemarkEmitterAnalysis>(*F);
286 // FIXME: This should probably be optional rather than required.
287 if (!ORE)
288 report_fatal_error("LICM: OptimizationRemarkEmitterAnalysis not "
289 "cached at a higher level");
290
291 LoopInvariantCodeMotion LICM(LicmMssaOptCap, LicmMssaNoAccForPromotionCap);
292 if (!LICM.runOnLoop(&L, &AR.AA, &AR.LI, &AR.DT, &AR.TLI, &AR.TTI, &AR.SE,
293 AR.MSSA, ORE, true))
294 return PreservedAnalyses::all();
295
296 auto PA = getLoopPassPreservedAnalyses();
297
298 PA.preserve<DominatorTreeAnalysis>();
299 PA.preserve<LoopAnalysis>();
300 if (AR.MSSA)
301 PA.preserve<MemorySSAAnalysis>();
302
303 return PA;
304}
305
306char LegacyLICMPass::ID = 0;
307INITIALIZE_PASS_BEGIN(LegacyLICMPass, "licm", "Loop Invariant Code Motion",static void *initializeLegacyLICMPassPassOnce(PassRegistry &
Registry) {
308 false, false)static void *initializeLegacyLICMPassPassOnce(PassRegistry &
Registry) {
309INITIALIZE_PASS_DEPENDENCY(LoopPass)initializeLoopPassPass(Registry);
310INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
311INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry);
312INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
313INITIALIZE_PASS_END(LegacyLICMPass, "licm", "Loop Invariant Code Motion", false,PassInfo *PI = new PassInfo( "Loop Invariant Code Motion", "licm"
, &LegacyLICMPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<LegacyLICMPass>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeLegacyLICMPassPassFlag
; void llvm::initializeLegacyLICMPassPass(PassRegistry &Registry
) { llvm::call_once(InitializeLegacyLICMPassPassFlag, initializeLegacyLICMPassPassOnce
, std::ref(Registry)); }
314 false)PassInfo *PI = new PassInfo( "Loop Invariant Code Motion", "licm"
, &LegacyLICMPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<LegacyLICMPass>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeLegacyLICMPassPassFlag
; void llvm::initializeLegacyLICMPassPass(PassRegistry &Registry
) { llvm::call_once(InitializeLegacyLICMPassPassFlag, initializeLegacyLICMPassPassOnce
, std::ref(Registry)); }
315
316Pass *llvm::createLICMPass() { return new LegacyLICMPass(); }
317Pass *llvm::createLICMPass(unsigned LicmMssaOptCap,
318 unsigned LicmMssaNoAccForPromotionCap) {
319 return new LegacyLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap);
320}
321
322/// Hoist expressions out of the specified loop. Note, alias info for inner
323/// loop is not preserved so it is not a good idea to run LICM multiple
324/// times on one loop.
325/// We should delete AST for inner loops in the new pass manager to avoid
326/// memory leak.
327///
328bool LoopInvariantCodeMotion::runOnLoop(
329 Loop *L, AliasAnalysis *AA, LoopInfo *LI, DominatorTree *DT,
330 TargetLibraryInfo *TLI, TargetTransformInfo *TTI, ScalarEvolution *SE,
331 MemorySSA *MSSA, OptimizationRemarkEmitter *ORE, bool DeleteAST) {
332 bool Changed = false;
333
334 assert(L->isLCSSAForm(*DT) && "Loop is not in LCSSA form.")((L->isLCSSAForm(*DT) && "Loop is not in LCSSA form."
) ? static_cast<void> (0) : __assert_fail ("L->isLCSSAForm(*DT) && \"Loop is not in LCSSA form.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 334, __PRETTY_FUNCTION__))
;
335
336 // If this loop has metadata indicating that LICM is not to be performed then
337 // just exit.
338 if (hasDisableLICMTransformsHint(L)) {
339 return false;
340 }
341
342 std::unique_ptr<AliasSetTracker> CurAST;
343 std::unique_ptr<MemorySSAUpdater> MSSAU;
344 bool NoOfMemAccTooLarge = false;
345 unsigned LicmMssaOptCounter = 0;
346
347 if (!MSSA) {
348 LLVM_DEBUG(dbgs() << "LICM: Using Alias Set Tracker.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM: Using Alias Set Tracker.\n"
; } } while (false)
;
349 CurAST = collectAliasInfoForLoop(L, LI, AA);
350 } else {
351 LLVM_DEBUG(dbgs() << "LICM: Using MemorySSA.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM: Using MemorySSA.\n"; } } while
(false)
;
352 MSSAU = std::make_unique<MemorySSAUpdater>(MSSA);
353
354 unsigned AccessCapCount = 0;
355 for (auto *BB : L->getBlocks()) {
356 if (auto *Accesses = MSSA->getBlockAccesses(BB)) {
357 for (const auto &MA : *Accesses) {
358 (void)MA;
359 AccessCapCount++;
360 if (AccessCapCount > LicmMssaNoAccForPromotionCap) {
361 NoOfMemAccTooLarge = true;
362 break;
363 }
364 }
365 }
366 if (NoOfMemAccTooLarge)
367 break;
368 }
369 }
370
371 // Get the preheader block to move instructions into...
372 BasicBlock *Preheader = L->getLoopPreheader();
373
374 // Compute loop safety information.
375 ICFLoopSafetyInfo SafetyInfo(DT);
376 SafetyInfo.computeLoopSafetyInfo(L);
377
378 // We want to visit all of the instructions in this loop... that are not parts
379 // of our subloops (they have already had their invariants hoisted out of
380 // their loop, into this loop, so there is no need to process the BODIES of
381 // the subloops).
382 //
383 // Traverse the body of the loop in depth first order on the dominator tree so
384 // that we are guaranteed to see definitions before we see uses. This allows
385 // us to sink instructions in one pass, without iteration. After sinking
386 // instructions, we perform another pass to hoist them out of the loop.
387 SinkAndHoistLICMFlags Flags = {NoOfMemAccTooLarge, LicmMssaOptCounter,
388 LicmMssaOptCap, LicmMssaNoAccForPromotionCap,
389 /*IsSink=*/true};
390 if (L->hasDedicatedExits())
391 Changed |= sinkRegion(DT->getNode(L->getHeader()), AA, LI, DT, TLI, TTI, L,
392 CurAST.get(), MSSAU.get(), &SafetyInfo, Flags, ORE);
393 Flags.IsSink = false;
394 if (Preheader)
395 Changed |=
396 hoistRegion(DT->getNode(L->getHeader()), AA, LI, DT, TLI, L,
397 CurAST.get(), MSSAU.get(), SE, &SafetyInfo, Flags, ORE);
398
399 // Now that all loop invariants have been removed from the loop, promote any
400 // memory references to scalars that we can.
401 // Don't sink stores from loops without dedicated block exits. Exits
402 // containing indirect branches are not transformed by loop simplify,
403 // make sure we catch that. An additional load may be generated in the
404 // preheader for SSA updater, so also avoid sinking when no preheader
405 // is available.
406 if (!DisablePromotion && Preheader && L->hasDedicatedExits() &&
407 !NoOfMemAccTooLarge) {
408 // Figure out the loop exits and their insertion points
409 SmallVector<BasicBlock *, 8> ExitBlocks;
410 L->getUniqueExitBlocks(ExitBlocks);
411
412 // We can't insert into a catchswitch.
413 bool HasCatchSwitch = llvm::any_of(ExitBlocks, [](BasicBlock *Exit) {
414 return isa<CatchSwitchInst>(Exit->getTerminator());
415 });
416
417 if (!HasCatchSwitch) {
418 SmallVector<Instruction *, 8> InsertPts;
419 SmallVector<MemoryAccess *, 8> MSSAInsertPts;
420 InsertPts.reserve(ExitBlocks.size());
421 if (MSSAU)
422 MSSAInsertPts.reserve(ExitBlocks.size());
423 for (BasicBlock *ExitBlock : ExitBlocks) {
424 InsertPts.push_back(&*ExitBlock->getFirstInsertionPt());
425 if (MSSAU)
426 MSSAInsertPts.push_back(nullptr);
427 }
428
429 PredIteratorCache PIC;
430
431 bool Promoted = false;
432
433 // Build an AST using MSSA.
434 if (!CurAST.get())
435 CurAST = collectAliasInfoForLoopWithMSSA(L, AA, MSSAU.get());
436
437 // Loop over all of the alias sets in the tracker object.
438 for (AliasSet &AS : *CurAST) {
439 // We can promote this alias set if it has a store, if it is a "Must"
440 // alias set, if the pointer is loop invariant, and if we are not
441 // eliminating any volatile loads or stores.
442 if (AS.isForwardingAliasSet() || !AS.isMod() || !AS.isMustAlias() ||
443 !L->isLoopInvariant(AS.begin()->getValue()))
444 continue;
445
446 assert(((!AS.empty() && "Must alias set should have at least one pointer element in it!"
) ? static_cast<void> (0) : __assert_fail ("!AS.empty() && \"Must alias set should have at least one pointer element in it!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 448, __PRETTY_FUNCTION__))
447 !AS.empty() &&((!AS.empty() && "Must alias set should have at least one pointer element in it!"
) ? static_cast<void> (0) : __assert_fail ("!AS.empty() && \"Must alias set should have at least one pointer element in it!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 448, __PRETTY_FUNCTION__))
448 "Must alias set should have at least one pointer element in it!")((!AS.empty() && "Must alias set should have at least one pointer element in it!"
) ? static_cast<void> (0) : __assert_fail ("!AS.empty() && \"Must alias set should have at least one pointer element in it!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 448, __PRETTY_FUNCTION__))
;
449
450 SmallSetVector<Value *, 8> PointerMustAliases;
451 for (const auto &ASI : AS)
452 PointerMustAliases.insert(ASI.getValue());
453
454 Promoted |= promoteLoopAccessesToScalars(
455 PointerMustAliases, ExitBlocks, InsertPts, MSSAInsertPts, PIC, LI,
456 DT, TLI, L, CurAST.get(), MSSAU.get(), &SafetyInfo, ORE);
457 }
458
459 // Once we have promoted values across the loop body we have to
460 // recursively reform LCSSA as any nested loop may now have values defined
461 // within the loop used in the outer loop.
462 // FIXME: This is really heavy handed. It would be a bit better to use an
463 // SSAUpdater strategy during promotion that was LCSSA aware and reformed
464 // it as it went.
465 if (Promoted)
466 formLCSSARecursively(*L, *DT, LI, SE);
467
468 Changed |= Promoted;
469 }
470 }
471
472 // Check that neither this loop nor its parent have had LCSSA broken. LICM is
473 // specifically moving instructions across the loop boundary and so it is
474 // especially in need of sanity checking here.
475 assert(L->isLCSSAForm(*DT) && "Loop not left in LCSSA form after LICM!")((L->isLCSSAForm(*DT) && "Loop not left in LCSSA form after LICM!"
) ? static_cast<void> (0) : __assert_fail ("L->isLCSSAForm(*DT) && \"Loop not left in LCSSA form after LICM!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 475, __PRETTY_FUNCTION__))
;
476 assert((!L->getParentLoop() || L->getParentLoop()->isLCSSAForm(*DT)) &&(((!L->getParentLoop() || L->getParentLoop()->isLCSSAForm
(*DT)) && "Parent loop not left in LCSSA form after LICM!"
) ? static_cast<void> (0) : __assert_fail ("(!L->getParentLoop() || L->getParentLoop()->isLCSSAForm(*DT)) && \"Parent loop not left in LCSSA form after LICM!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 477, __PRETTY_FUNCTION__))
477 "Parent loop not left in LCSSA form after LICM!")(((!L->getParentLoop() || L->getParentLoop()->isLCSSAForm
(*DT)) && "Parent loop not left in LCSSA form after LICM!"
) ? static_cast<void> (0) : __assert_fail ("(!L->getParentLoop() || L->getParentLoop()->isLCSSAForm(*DT)) && \"Parent loop not left in LCSSA form after LICM!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 477, __PRETTY_FUNCTION__))
;
478
479 // If this loop is nested inside of another one, save the alias information
480 // for when we process the outer loop.
481 if (!MSSAU.get() && CurAST.get() && L->getParentLoop() && !DeleteAST)
482 LoopToAliasSetMap[L] = std::move(CurAST);
483
484 if (MSSAU.get() && VerifyMemorySSA)
485 MSSAU->getMemorySSA()->verifyMemorySSA();
486
487 if (Changed && SE)
488 SE->forgetLoopDispositions(L);
489 return Changed;
490}
491
492/// Walk the specified region of the CFG (defined by all blocks dominated by
493/// the specified block, and that are in the current loop) in reverse depth
494/// first order w.r.t the DominatorTree. This allows us to visit uses before
495/// definitions, allowing us to sink a loop body in one pass without iteration.
496///
497bool llvm::sinkRegion(DomTreeNode *N, AliasAnalysis *AA, LoopInfo *LI,
498 DominatorTree *DT, TargetLibraryInfo *TLI,
499 TargetTransformInfo *TTI, Loop *CurLoop,
500 AliasSetTracker *CurAST, MemorySSAUpdater *MSSAU,
501 ICFLoopSafetyInfo *SafetyInfo,
502 SinkAndHoistLICMFlags &Flags,
503 OptimizationRemarkEmitter *ORE) {
504
505 // Verify inputs.
506 assert(N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr &&((N != nullptr && AA != nullptr && LI != nullptr
&& DT != nullptr && CurLoop != nullptr &&
SafetyInfo != nullptr && "Unexpected input to sinkRegion."
) ? static_cast<void> (0) : __assert_fail ("N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr && CurLoop != nullptr && SafetyInfo != nullptr && \"Unexpected input to sinkRegion.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 508, __PRETTY_FUNCTION__))
507 CurLoop != nullptr && SafetyInfo != nullptr &&((N != nullptr && AA != nullptr && LI != nullptr
&& DT != nullptr && CurLoop != nullptr &&
SafetyInfo != nullptr && "Unexpected input to sinkRegion."
) ? static_cast<void> (0) : __assert_fail ("N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr && CurLoop != nullptr && SafetyInfo != nullptr && \"Unexpected input to sinkRegion.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 508, __PRETTY_FUNCTION__))
508 "Unexpected input to sinkRegion.")((N != nullptr && AA != nullptr && LI != nullptr
&& DT != nullptr && CurLoop != nullptr &&
SafetyInfo != nullptr && "Unexpected input to sinkRegion."
) ? static_cast<void> (0) : __assert_fail ("N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr && CurLoop != nullptr && SafetyInfo != nullptr && \"Unexpected input to sinkRegion.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 508, __PRETTY_FUNCTION__))
;
509 assert(((CurAST != nullptr) ^ (MSSAU != nullptr)) &&((((CurAST != nullptr) ^ (MSSAU != nullptr)) && "Either AliasSetTracker or MemorySSA should be initialized."
) ? static_cast<void> (0) : __assert_fail ("((CurAST != nullptr) ^ (MSSAU != nullptr)) && \"Either AliasSetTracker or MemorySSA should be initialized.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 510, __PRETTY_FUNCTION__))
510 "Either AliasSetTracker or MemorySSA should be initialized.")((((CurAST != nullptr) ^ (MSSAU != nullptr)) && "Either AliasSetTracker or MemorySSA should be initialized."
) ? static_cast<void> (0) : __assert_fail ("((CurAST != nullptr) ^ (MSSAU != nullptr)) && \"Either AliasSetTracker or MemorySSA should be initialized.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 510, __PRETTY_FUNCTION__))
;
511
512 // We want to visit children before parents. We will enque all the parents
513 // before their children in the worklist and process the worklist in reverse
514 // order.
515 SmallVector<DomTreeNode *, 16> Worklist = collectChildrenInLoop(N, CurLoop);
516
517 bool Changed = false;
518 for (DomTreeNode *DTN : reverse(Worklist)) {
519 BasicBlock *BB = DTN->getBlock();
520 // Only need to process the contents of this block if it is not part of a
521 // subloop (which would already have been processed).
522 if (inSubLoop(BB, CurLoop, LI))
523 continue;
524
525 for (BasicBlock::iterator II = BB->end(); II != BB->begin();) {
526 Instruction &I = *--II;
527
528 // If the instruction is dead, we would try to sink it because it isn't
529 // used in the loop, instead, just delete it.
530 if (isInstructionTriviallyDead(&I, TLI)) {
531 LLVM_DEBUG(dbgs() << "LICM deleting dead inst: " << I << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM deleting dead inst: " <<
I << '\n'; } } while (false)
;
532 salvageDebugInfo(I);
533 ++II;
534 eraseInstruction(I, *SafetyInfo, CurAST, MSSAU);
535 Changed = true;
536 continue;
537 }
538
539 // Check to see if we can sink this instruction to the exit blocks
540 // of the loop. We can do this if the all users of the instruction are
541 // outside of the loop. In this case, it doesn't even matter if the
542 // operands of the instruction are loop invariant.
543 //
544 bool FreeInLoop = false;
545 if (isNotUsedOrFreeInLoop(I, CurLoop, SafetyInfo, TTI, FreeInLoop) &&
546 canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, MSSAU, true, &Flags,
547 ORE) &&
548 !I.mayHaveSideEffects()) {
549 if (sink(I, LI, DT, CurLoop, SafetyInfo, MSSAU, ORE)) {
550 if (!FreeInLoop) {
551 ++II;
552 eraseInstruction(I, *SafetyInfo, CurAST, MSSAU);
553 }
554 Changed = true;
555 }
556 }
557 }
558 }
559 if (MSSAU && VerifyMemorySSA)
560 MSSAU->getMemorySSA()->verifyMemorySSA();
561 return Changed;
562}
563
564namespace {
565// This is a helper class for hoistRegion to make it able to hoist control flow
566// in order to be able to hoist phis. The way this works is that we initially
567// start hoisting to the loop preheader, and when we see a loop invariant branch
568// we make note of this. When we then come to hoist an instruction that's
569// conditional on such a branch we duplicate the branch and the relevant control
570// flow, then hoist the instruction into the block corresponding to its original
571// block in the duplicated control flow.
572class ControlFlowHoister {
573private:
574 // Information about the loop we are hoisting from
575 LoopInfo *LI;
576 DominatorTree *DT;
577 Loop *CurLoop;
578 MemorySSAUpdater *MSSAU;
579
580 // A map of blocks in the loop to the block their instructions will be hoisted
581 // to.
582 DenseMap<BasicBlock *, BasicBlock *> HoistDestinationMap;
583
584 // The branches that we can hoist, mapped to the block that marks a
585 // convergence point of their control flow.
586 DenseMap<BranchInst *, BasicBlock *> HoistableBranches;
587
588public:
589 ControlFlowHoister(LoopInfo *LI, DominatorTree *DT, Loop *CurLoop,
590 MemorySSAUpdater *MSSAU)
591 : LI(LI), DT(DT), CurLoop(CurLoop), MSSAU(MSSAU) {}
592
593 void registerPossiblyHoistableBranch(BranchInst *BI) {
594 // We can only hoist conditional branches with loop invariant operands.
595 if (!ControlFlowHoisting || !BI->isConditional() ||
596 !CurLoop->hasLoopInvariantOperands(BI))
597 return;
598
599 // The branch destinations need to be in the loop, and we don't gain
600 // anything by duplicating conditional branches with duplicate successors,
601 // as it's essentially the same as an unconditional branch.
602 BasicBlock *TrueDest = BI->getSuccessor(0);
603 BasicBlock *FalseDest = BI->getSuccessor(1);
604 if (!CurLoop->contains(TrueDest) || !CurLoop->contains(FalseDest) ||
605 TrueDest == FalseDest)
606 return;
607
608 // We can hoist BI if one branch destination is the successor of the other,
609 // or both have common successor which we check by seeing if the
610 // intersection of their successors is non-empty.
611 // TODO: This could be expanded to allowing branches where both ends
612 // eventually converge to a single block.
613 SmallPtrSet<BasicBlock *, 4> TrueDestSucc, FalseDestSucc;
614 TrueDestSucc.insert(succ_begin(TrueDest), succ_end(TrueDest));
615 FalseDestSucc.insert(succ_begin(FalseDest), succ_end(FalseDest));
616 BasicBlock *CommonSucc = nullptr;
617 if (TrueDestSucc.count(FalseDest)) {
618 CommonSucc = FalseDest;
619 } else if (FalseDestSucc.count(TrueDest)) {
620 CommonSucc = TrueDest;
621 } else {
622 set_intersect(TrueDestSucc, FalseDestSucc);
623 // If there's one common successor use that.
624 if (TrueDestSucc.size() == 1)
625 CommonSucc = *TrueDestSucc.begin();
626 // If there's more than one pick whichever appears first in the block list
627 // (we can't use the value returned by TrueDestSucc.begin() as it's
628 // unpredicatable which element gets returned).
629 else if (!TrueDestSucc.empty()) {
630 Function *F = TrueDest->getParent();
631 auto IsSucc = [&](BasicBlock &BB) { return TrueDestSucc.count(&BB); };
632 auto It = std::find_if(F->begin(), F->end(), IsSucc);
633 assert(It != F->end() && "Could not find successor in function")((It != F->end() && "Could not find successor in function"
) ? static_cast<void> (0) : __assert_fail ("It != F->end() && \"Could not find successor in function\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 633, __PRETTY_FUNCTION__))
;
634 CommonSucc = &*It;
635 }
636 }
637 // The common successor has to be dominated by the branch, as otherwise
638 // there will be some other path to the successor that will not be
639 // controlled by this branch so any phi we hoist would be controlled by the
640 // wrong condition. This also takes care of avoiding hoisting of loop back
641 // edges.
642 // TODO: In some cases this could be relaxed if the successor is dominated
643 // by another block that's been hoisted and we can guarantee that the
644 // control flow has been replicated exactly.
645 if (CommonSucc && DT->dominates(BI, CommonSucc))
646 HoistableBranches[BI] = CommonSucc;
647 }
648
649 bool canHoistPHI(PHINode *PN) {
650 // The phi must have loop invariant operands.
651 if (!ControlFlowHoisting || !CurLoop->hasLoopInvariantOperands(PN))
652 return false;
653 // We can hoist phis if the block they are in is the target of hoistable
654 // branches which cover all of the predecessors of the block.
655 SmallPtrSet<BasicBlock *, 8> PredecessorBlocks;
656 BasicBlock *BB = PN->getParent();
657 for (BasicBlock *PredBB : predecessors(BB))
658 PredecessorBlocks.insert(PredBB);
659 // If we have less predecessor blocks than predecessors then the phi will
660 // have more than one incoming value for the same block which we can't
661 // handle.
662 // TODO: This could be handled be erasing some of the duplicate incoming
663 // values.
664 if (PredecessorBlocks.size() != pred_size(BB))
665 return false;
666 for (auto &Pair : HoistableBranches) {
667 if (Pair.second == BB) {
668 // Which blocks are predecessors via this branch depends on if the
669 // branch is triangle-like or diamond-like.
670 if (Pair.first->getSuccessor(0) == BB) {
671 PredecessorBlocks.erase(Pair.first->getParent());
672 PredecessorBlocks.erase(Pair.first->getSuccessor(1));
673 } else if (Pair.first->getSuccessor(1) == BB) {
674 PredecessorBlocks.erase(Pair.first->getParent());
675 PredecessorBlocks.erase(Pair.first->getSuccessor(0));
676 } else {
677 PredecessorBlocks.erase(Pair.first->getSuccessor(0));
678 PredecessorBlocks.erase(Pair.first->getSuccessor(1));
679 }
680 }
681 }
682 // PredecessorBlocks will now be empty if for every predecessor of BB we
683 // found a hoistable branch source.
684 return PredecessorBlocks.empty();
685 }
686
687 BasicBlock *getOrCreateHoistedBlock(BasicBlock *BB) {
688 if (!ControlFlowHoisting)
689 return CurLoop->getLoopPreheader();
690 // If BB has already been hoisted, return that
691 if (HoistDestinationMap.count(BB))
692 return HoistDestinationMap[BB];
693
694 // Check if this block is conditional based on a pending branch
695 auto HasBBAsSuccessor =
696 [&](DenseMap<BranchInst *, BasicBlock *>::value_type &Pair) {
697 return BB != Pair.second && (Pair.first->getSuccessor(0) == BB ||
698 Pair.first->getSuccessor(1) == BB);
699 };
700 auto It = std::find_if(HoistableBranches.begin(), HoistableBranches.end(),
701 HasBBAsSuccessor);
702
703 // If not involved in a pending branch, hoist to preheader
704 BasicBlock *InitialPreheader = CurLoop->getLoopPreheader();
705 if (It == HoistableBranches.end()) {
706 LLVM_DEBUG(dbgs() << "LICM using " << InitialPreheader->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM using " << InitialPreheader
->getName() << " as hoist destination for " <<
BB->getName() << "\n"; } } while (false)
707 << " as hoist destination for " << BB->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM using " << InitialPreheader
->getName() << " as hoist destination for " <<
BB->getName() << "\n"; } } while (false)
708 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM using " << InitialPreheader
->getName() << " as hoist destination for " <<
BB->getName() << "\n"; } } while (false)
;
709 HoistDestinationMap[BB] = InitialPreheader;
710 return InitialPreheader;
711 }
712 BranchInst *BI = It->first;
713 assert(std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor) ==((std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor
) == HoistableBranches.end() && "BB is expected to be the target of at most one branch"
) ? static_cast<void> (0) : __assert_fail ("std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor) == HoistableBranches.end() && \"BB is expected to be the target of at most one branch\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 715, __PRETTY_FUNCTION__))
714 HoistableBranches.end() &&((std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor
) == HoistableBranches.end() && "BB is expected to be the target of at most one branch"
) ? static_cast<void> (0) : __assert_fail ("std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor) == HoistableBranches.end() && \"BB is expected to be the target of at most one branch\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 715, __PRETTY_FUNCTION__))
715 "BB is expected to be the target of at most one branch")((std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor
) == HoistableBranches.end() && "BB is expected to be the target of at most one branch"
) ? static_cast<void> (0) : __assert_fail ("std::find_if(++It, HoistableBranches.end(), HasBBAsSuccessor) == HoistableBranches.end() && \"BB is expected to be the target of at most one branch\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 715, __PRETTY_FUNCTION__))
;
716
717 LLVMContext &C = BB->getContext();
718 BasicBlock *TrueDest = BI->getSuccessor(0);
719 BasicBlock *FalseDest = BI->getSuccessor(1);
720 BasicBlock *CommonSucc = HoistableBranches[BI];
721 BasicBlock *HoistTarget = getOrCreateHoistedBlock(BI->getParent());
722
723 // Create hoisted versions of blocks that currently don't have them
724 auto CreateHoistedBlock = [&](BasicBlock *Orig) {
725 if (HoistDestinationMap.count(Orig))
726 return HoistDestinationMap[Orig];
727 BasicBlock *New =
728 BasicBlock::Create(C, Orig->getName() + ".licm", Orig->getParent());
729 HoistDestinationMap[Orig] = New;
730 DT->addNewBlock(New, HoistTarget);
731 if (CurLoop->getParentLoop())
732 CurLoop->getParentLoop()->addBasicBlockToLoop(New, *LI);
733 ++NumCreatedBlocks;
734 LLVM_DEBUG(dbgs() << "LICM created " << New->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM created " << New->
getName() << " as hoist destination for " << Orig
->getName() << "\n"; } } while (false)
735 << " as hoist destination for " << Orig->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM created " << New->
getName() << " as hoist destination for " << Orig
->getName() << "\n"; } } while (false)
736 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM created " << New->
getName() << " as hoist destination for " << Orig
->getName() << "\n"; } } while (false)
;
737 return New;
738 };
739 BasicBlock *HoistTrueDest = CreateHoistedBlock(TrueDest);
740 BasicBlock *HoistFalseDest = CreateHoistedBlock(FalseDest);
741 BasicBlock *HoistCommonSucc = CreateHoistedBlock(CommonSucc);
742
743 // Link up these blocks with branches.
744 if (!HoistCommonSucc->getTerminator()) {
745 // The new common successor we've generated will branch to whatever that
746 // hoist target branched to.
747 BasicBlock *TargetSucc = HoistTarget->getSingleSuccessor();
748 assert(TargetSucc && "Expected hoist target to have a single successor")((TargetSucc && "Expected hoist target to have a single successor"
) ? static_cast<void> (0) : __assert_fail ("TargetSucc && \"Expected hoist target to have a single successor\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 748, __PRETTY_FUNCTION__))
;
749 HoistCommonSucc->moveBefore(TargetSucc);
750 BranchInst::Create(TargetSucc, HoistCommonSucc);
751 }
752 if (!HoistTrueDest->getTerminator()) {
753 HoistTrueDest->moveBefore(HoistCommonSucc);
754 BranchInst::Create(HoistCommonSucc, HoistTrueDest);
755 }
756 if (!HoistFalseDest->getTerminator()) {
757 HoistFalseDest->moveBefore(HoistCommonSucc);
758 BranchInst::Create(HoistCommonSucc, HoistFalseDest);
759 }
760
761 // If BI is being cloned to what was originally the preheader then
762 // HoistCommonSucc will now be the new preheader.
763 if (HoistTarget == InitialPreheader) {
764 // Phis in the loop header now need to use the new preheader.
765 InitialPreheader->replaceSuccessorsPhiUsesWith(HoistCommonSucc);
766 if (MSSAU)
767 MSSAU->wireOldPredecessorsToNewImmediatePredecessor(
768 HoistTarget->getSingleSuccessor(), HoistCommonSucc, {HoistTarget});
769 // The new preheader dominates the loop header.
770 DomTreeNode *PreheaderNode = DT->getNode(HoistCommonSucc);
771 DomTreeNode *HeaderNode = DT->getNode(CurLoop->getHeader());
772 DT->changeImmediateDominator(HeaderNode, PreheaderNode);
773 // The preheader hoist destination is now the new preheader, with the
774 // exception of the hoist destination of this branch.
775 for (auto &Pair : HoistDestinationMap)
776 if (Pair.second == InitialPreheader && Pair.first != BI->getParent())
777 Pair.second = HoistCommonSucc;
778 }
779
780 // Now finally clone BI.
781 ReplaceInstWithInst(
782 HoistTarget->getTerminator(),
783 BranchInst::Create(HoistTrueDest, HoistFalseDest, BI->getCondition()));
784 ++NumClonedBranches;
785
786 assert(CurLoop->getLoopPreheader() &&((CurLoop->getLoopPreheader() && "Hoisting blocks should not have destroyed preheader"
) ? static_cast<void> (0) : __assert_fail ("CurLoop->getLoopPreheader() && \"Hoisting blocks should not have destroyed preheader\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 787, __PRETTY_FUNCTION__))
787 "Hoisting blocks should not have destroyed preheader")((CurLoop->getLoopPreheader() && "Hoisting blocks should not have destroyed preheader"
) ? static_cast<void> (0) : __assert_fail ("CurLoop->getLoopPreheader() && \"Hoisting blocks should not have destroyed preheader\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 787, __PRETTY_FUNCTION__))
;
788 return HoistDestinationMap[BB];
789 }
790};
791} // namespace
792
793
794/// Return true if we know how to rewrite all uses of the given alloca after
795/// hoisting it out of the loop. The main concerns are a) potential captures
796/// and b) invariant.start markers which don't capture, but are no longer
797/// valid w/o a corresponding invariant.end.
798static bool canRewriteUsesOfAlloca(AllocaInst &AI) {
799 // TODO: This looks a lot like capture tracking, but we need to remove any
800 // invariant starts if we extend the lifetime of the alloca by hoisting it.
801 // We should probably refactor capture tracking into a form which allows us
802 // to reuse the relevant bits and remove the duplicated logic here.
803
804 SmallVector<Use *, 16> Worklist;
805 for (Use &U : AI.uses())
806 Worklist.push_back(&U);
807
808 unsigned NumUsesExplored = 0;
809 while (!Worklist.empty()) {
810 Use *U = Worklist.pop_back_val();
811 Instruction *I = cast<Instruction>(U->getUser());
812 NumUsesExplored++;
813 if (NumUsesExplored > DefaultMaxUsesToExplore)
814 return false;
815 // Non capturing, terminating uses
816 if (isa<LoadInst>(I) ||
817 (isa<StoreInst>(I) && U->getOperandNo() == 1))
818 continue;
819 // Non capturing, non-terminating
820 if (!isa<BitCastInst>(I) && !isa<GetElementPtrInst>(I))
821 return false;
822 for (Use &U : I->uses())
823 Worklist.push_back(&U);
824 }
825 return true;
826}
827
828/// Walk the specified region of the CFG (defined by all blocks dominated by
829/// the specified block, and that are in the current loop) in depth first
830/// order w.r.t the DominatorTree. This allows us to visit definitions before
831/// uses, allowing us to hoist a loop body in one pass without iteration.
832///
833bool llvm::hoistRegion(DomTreeNode *N, AliasAnalysis *AA, LoopInfo *LI,
834 DominatorTree *DT, TargetLibraryInfo *TLI, Loop *CurLoop,
835 AliasSetTracker *CurAST, MemorySSAUpdater *MSSAU,
836 ScalarEvolution *SE, ICFLoopSafetyInfo *SafetyInfo,
837 SinkAndHoistLICMFlags &Flags,
838 OptimizationRemarkEmitter *ORE) {
839 // Verify inputs.
840 assert(N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr &&((N != nullptr && AA != nullptr && LI != nullptr
&& DT != nullptr && CurLoop != nullptr &&
SafetyInfo != nullptr && "Unexpected input to hoistRegion."
) ? static_cast<void> (0) : __assert_fail ("N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr && CurLoop != nullptr && SafetyInfo != nullptr && \"Unexpected input to hoistRegion.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 842, __PRETTY_FUNCTION__))
841 CurLoop != nullptr && SafetyInfo != nullptr &&((N != nullptr && AA != nullptr && LI != nullptr
&& DT != nullptr && CurLoop != nullptr &&
SafetyInfo != nullptr && "Unexpected input to hoistRegion."
) ? static_cast<void> (0) : __assert_fail ("N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr && CurLoop != nullptr && SafetyInfo != nullptr && \"Unexpected input to hoistRegion.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 842, __PRETTY_FUNCTION__))
842 "Unexpected input to hoistRegion.")((N != nullptr && AA != nullptr && LI != nullptr
&& DT != nullptr && CurLoop != nullptr &&
SafetyInfo != nullptr && "Unexpected input to hoistRegion."
) ? static_cast<void> (0) : __assert_fail ("N != nullptr && AA != nullptr && LI != nullptr && DT != nullptr && CurLoop != nullptr && SafetyInfo != nullptr && \"Unexpected input to hoistRegion.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 842, __PRETTY_FUNCTION__))
;
843 assert(((CurAST != nullptr) ^ (MSSAU != nullptr)) &&((((CurAST != nullptr) ^ (MSSAU != nullptr)) && "Either AliasSetTracker or MemorySSA should be initialized."
) ? static_cast<void> (0) : __assert_fail ("((CurAST != nullptr) ^ (MSSAU != nullptr)) && \"Either AliasSetTracker or MemorySSA should be initialized.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 844, __PRETTY_FUNCTION__))
844 "Either AliasSetTracker or MemorySSA should be initialized.")((((CurAST != nullptr) ^ (MSSAU != nullptr)) && "Either AliasSetTracker or MemorySSA should be initialized."
) ? static_cast<void> (0) : __assert_fail ("((CurAST != nullptr) ^ (MSSAU != nullptr)) && \"Either AliasSetTracker or MemorySSA should be initialized.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 844, __PRETTY_FUNCTION__))
;
845
846 ControlFlowHoister CFH(LI, DT, CurLoop, MSSAU);
847
848 // Keep track of instructions that have been hoisted, as they may need to be
849 // re-hoisted if they end up not dominating all of their uses.
850 SmallVector<Instruction *, 16> HoistedInstructions;
851
852 // For PHI hoisting to work we need to hoist blocks before their successors.
853 // We can do this by iterating through the blocks in the loop in reverse
854 // post-order.
855 LoopBlocksRPO Worklist(CurLoop);
856 Worklist.perform(LI);
857 bool Changed = false;
858 for (BasicBlock *BB : Worklist) {
859 // Only need to process the contents of this block if it is not part of a
860 // subloop (which would already have been processed).
861 if (inSubLoop(BB, CurLoop, LI))
862 continue;
863
864 for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E;) {
865 Instruction &I = *II++;
866 // Try constant folding this instruction. If all the operands are
867 // constants, it is technically hoistable, but it would be better to
868 // just fold it.
869 if (Constant *C = ConstantFoldInstruction(
870 &I, I.getModule()->getDataLayout(), TLI)) {
871 LLVM_DEBUG(dbgs() << "LICM folding inst: " << I << " --> " << *Cdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM folding inst: " << I <<
" --> " << *C << '\n'; } } while (false)
872 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM folding inst: " << I <<
" --> " << *C << '\n'; } } while (false)
;
873 if (CurAST)
874 CurAST->copyValue(&I, C);
875 // FIXME MSSA: Such replacements may make accesses unoptimized (D51960).
876 I.replaceAllUsesWith(C);
877 if (isInstructionTriviallyDead(&I, TLI))
878 eraseInstruction(I, *SafetyInfo, CurAST, MSSAU);
879 Changed = true;
880 continue;
881 }
882
883 // Try hoisting the instruction out to the preheader. We can only do
884 // this if all of the operands of the instruction are loop invariant and
885 // if it is safe to hoist the instruction.
886 // TODO: It may be safe to hoist if we are hoisting to a conditional block
887 // and we have accurately duplicated the control flow from the loop header
888 // to that block.
889 if (CurLoop->hasLoopInvariantOperands(&I) &&
890 canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, MSSAU, true, &Flags,
891 ORE) &&
892 isSafeToExecuteUnconditionally(
893 I, DT, CurLoop, SafetyInfo, ORE,
894 CurLoop->getLoopPreheader()->getTerminator())) {
895 hoist(I, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB), SafetyInfo,
896 MSSAU, SE, ORE);
897 HoistedInstructions.push_back(&I);
898 Changed = true;
899 continue;
900 }
901
902 // Attempt to remove floating point division out of the loop by
903 // converting it to a reciprocal multiplication.
904 if (I.getOpcode() == Instruction::FDiv &&
905 CurLoop->isLoopInvariant(I.getOperand(1)) &&
906 I.hasAllowReciprocal()) {
907 auto Divisor = I.getOperand(1);
908 auto One = llvm::ConstantFP::get(Divisor->getType(), 1.0);
909 auto ReciprocalDivisor = BinaryOperator::CreateFDiv(One, Divisor);
910 ReciprocalDivisor->setFastMathFlags(I.getFastMathFlags());
911 SafetyInfo->insertInstructionTo(ReciprocalDivisor, I.getParent());
912 ReciprocalDivisor->insertBefore(&I);
913
914 auto Product =
915 BinaryOperator::CreateFMul(I.getOperand(0), ReciprocalDivisor);
916 Product->setFastMathFlags(I.getFastMathFlags());
917 SafetyInfo->insertInstructionTo(Product, I.getParent());
918 Product->insertAfter(&I);
919 I.replaceAllUsesWith(Product);
920 eraseInstruction(I, *SafetyInfo, CurAST, MSSAU);
921
922 hoist(*ReciprocalDivisor, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB),
923 SafetyInfo, MSSAU, SE, ORE);
924 HoistedInstructions.push_back(ReciprocalDivisor);
925 Changed = true;
926 continue;
927 }
928
929 auto IsInvariantStart = [&](Instruction &I) {
930 using namespace PatternMatch;
931 return I.use_empty() &&
932 match(&I, m_Intrinsic<Intrinsic::invariant_start>());
933 };
934 auto MustExecuteWithoutWritesBefore = [&](Instruction &I) {
935 return SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop) &&
936 SafetyInfo->doesNotWriteMemoryBefore(I, CurLoop);
937 };
938 if ((IsInvariantStart(I) || isGuard(&I)) &&
939 CurLoop->hasLoopInvariantOperands(&I) &&
940 MustExecuteWithoutWritesBefore(I)) {
941 hoist(I, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB), SafetyInfo,
942 MSSAU, SE, ORE);
943 HoistedInstructions.push_back(&I);
944 Changed = true;
945 continue;
946 }
947
948 if (isa<AllocaInst>(&I) &&
949 SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop) &&
950 canRewriteUsesOfAlloca(cast<AllocaInst>(I))) {
951 hoist(I, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB), SafetyInfo,
952 MSSAU, SE, ORE);
953 HoistedInstructions.push_back(&I);
954 Changed = true;
955 continue;
956 }
957
958 if (PHINode *PN = dyn_cast<PHINode>(&I)) {
959 if (CFH.canHoistPHI(PN)) {
960 // Redirect incoming blocks first to ensure that we create hoisted
961 // versions of those blocks before we hoist the phi.
962 for (unsigned int i = 0; i < PN->getNumIncomingValues(); ++i)
963 PN->setIncomingBlock(
964 i, CFH.getOrCreateHoistedBlock(PN->getIncomingBlock(i)));
965 hoist(*PN, DT, CurLoop, CFH.getOrCreateHoistedBlock(BB), SafetyInfo,
966 MSSAU, SE, ORE);
967 assert(DT->dominates(PN, BB) && "Conditional PHIs not expected")((DT->dominates(PN, BB) && "Conditional PHIs not expected"
) ? static_cast<void> (0) : __assert_fail ("DT->dominates(PN, BB) && \"Conditional PHIs not expected\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 967, __PRETTY_FUNCTION__))
;
968 Changed = true;
969 continue;
970 }
971 }
972
973 // Remember possibly hoistable branches so we can actually hoist them
974 // later if needed.
975 if (BranchInst *BI = dyn_cast<BranchInst>(&I))
976 CFH.registerPossiblyHoistableBranch(BI);
977 }
978 }
979
980 // If we hoisted instructions to a conditional block they may not dominate
981 // their uses that weren't hoisted (such as phis where some operands are not
982 // loop invariant). If so make them unconditional by moving them to their
983 // immediate dominator. We iterate through the instructions in reverse order
984 // which ensures that when we rehoist an instruction we rehoist its operands,
985 // and also keep track of where in the block we are rehoisting to to make sure
986 // that we rehoist instructions before the instructions that use them.
987 Instruction *HoistPoint = nullptr;
988 if (ControlFlowHoisting) {
989 for (Instruction *I : reverse(HoistedInstructions)) {
990 if (!llvm::all_of(I->uses(),
991 [&](Use &U) { return DT->dominates(I, U); })) {
992 BasicBlock *Dominator =
993 DT->getNode(I->getParent())->getIDom()->getBlock();
994 if (!HoistPoint || !DT->dominates(HoistPoint->getParent(), Dominator)) {
995 if (HoistPoint)
996 assert(DT->dominates(Dominator, HoistPoint->getParent()) &&((DT->dominates(Dominator, HoistPoint->getParent()) &&
"New hoist point expected to dominate old hoist point") ? static_cast
<void> (0) : __assert_fail ("DT->dominates(Dominator, HoistPoint->getParent()) && \"New hoist point expected to dominate old hoist point\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 997, __PRETTY_FUNCTION__))
997 "New hoist point expected to dominate old hoist point")((DT->dominates(Dominator, HoistPoint->getParent()) &&
"New hoist point expected to dominate old hoist point") ? static_cast
<void> (0) : __assert_fail ("DT->dominates(Dominator, HoistPoint->getParent()) && \"New hoist point expected to dominate old hoist point\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 997, __PRETTY_FUNCTION__))
;
998 HoistPoint = Dominator->getTerminator();
999 }
1000 LLVM_DEBUG(dbgs() << "LICM rehoisting to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM rehoisting to " << HoistPoint
->getParent()->getName() << ": " << *I <<
"\n"; } } while (false)
1001 << HoistPoint->getParent()->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM rehoisting to " << HoistPoint
->getParent()->getName() << ": " << *I <<
"\n"; } } while (false)
1002 << ": " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM rehoisting to " << HoistPoint
->getParent()->getName() << ": " << *I <<
"\n"; } } while (false)
;
1003 moveInstructionBefore(*I, *HoistPoint, *SafetyInfo, MSSAU, SE);
1004 HoistPoint = I;
1005 Changed = true;
1006 }
1007 }
1008 }
1009 if (MSSAU && VerifyMemorySSA)
1010 MSSAU->getMemorySSA()->verifyMemorySSA();
1011
1012 // Now that we've finished hoisting make sure that LI and DT are still
1013 // valid.
1014#ifdef EXPENSIVE_CHECKS
1015 if (Changed) {
1016 assert(DT->verify(DominatorTree::VerificationLevel::Fast) &&((DT->verify(DominatorTree::VerificationLevel::Fast) &&
"Dominator tree verification failed") ? static_cast<void>
(0) : __assert_fail ("DT->verify(DominatorTree::VerificationLevel::Fast) && \"Dominator tree verification failed\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1017, __PRETTY_FUNCTION__))
1017 "Dominator tree verification failed")((DT->verify(DominatorTree::VerificationLevel::Fast) &&
"Dominator tree verification failed") ? static_cast<void>
(0) : __assert_fail ("DT->verify(DominatorTree::VerificationLevel::Fast) && \"Dominator tree verification failed\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1017, __PRETTY_FUNCTION__))
;
1018 LI->verify(*DT);
1019 }
1020#endif
1021
1022 return Changed;
1023}
1024
1025// Return true if LI is invariant within scope of the loop. LI is invariant if
1026// CurLoop is dominated by an invariant.start representing the same memory
1027// location and size as the memory location LI loads from, and also the
1028// invariant.start has no uses.
1029static bool isLoadInvariantInLoop(LoadInst *LI, DominatorTree *DT,
1030 Loop *CurLoop) {
1031 Value *Addr = LI->getOperand(0);
1032 const DataLayout &DL = LI->getModule()->getDataLayout();
1033 const uint32_t LocSizeInBits = DL.getTypeSizeInBits(LI->getType());
1034
1035 // if the type is i8 addrspace(x)*, we know this is the type of
1036 // llvm.invariant.start operand
1037 auto *PtrInt8Ty = PointerType::get(Type::getInt8Ty(LI->getContext()),
1038 LI->getPointerAddressSpace());
1039 unsigned BitcastsVisited = 0;
1040 // Look through bitcasts until we reach the i8* type (this is invariant.start
1041 // operand type).
1042 while (Addr->getType() != PtrInt8Ty) {
1043 auto *BC = dyn_cast<BitCastInst>(Addr);
1044 // Avoid traversing high number of bitcast uses.
1045 if (++BitcastsVisited > MaxNumUsesTraversed || !BC)
1046 return false;
1047 Addr = BC->getOperand(0);
1048 }
1049
1050 unsigned UsesVisited = 0;
1051 // Traverse all uses of the load operand value, to see if invariant.start is
1052 // one of the uses, and whether it dominates the load instruction.
1053 for (auto *U : Addr->users()) {
1054 // Avoid traversing for Load operand with high number of users.
1055 if (++UsesVisited > MaxNumUsesTraversed)
1056 return false;
1057 IntrinsicInst *II = dyn_cast<IntrinsicInst>(U);
1058 // If there are escaping uses of invariant.start instruction, the load maybe
1059 // non-invariant.
1060 if (!II || II->getIntrinsicID() != Intrinsic::invariant_start ||
1061 !II->use_empty())
1062 continue;
1063 unsigned InvariantSizeInBits =
1064 cast<ConstantInt>(II->getArgOperand(0))->getSExtValue() * 8;
1065 // Confirm the invariant.start location size contains the load operand size
1066 // in bits. Also, the invariant.start should dominate the load, and we
1067 // should not hoist the load out of a loop that contains this dominating
1068 // invariant.start.
1069 if (LocSizeInBits <= InvariantSizeInBits &&
1070 DT->properlyDominates(II->getParent(), CurLoop->getHeader()))
1071 return true;
1072 }
1073
1074 return false;
1075}
1076
1077namespace {
1078/// Return true if-and-only-if we know how to (mechanically) both hoist and
1079/// sink a given instruction out of a loop. Does not address legality
1080/// concerns such as aliasing or speculation safety.
1081bool isHoistableAndSinkableInst(Instruction &I) {
1082 // Only these instructions are hoistable/sinkable.
1083 return (isa<LoadInst>(I) || isa<StoreInst>(I) || isa<CallInst>(I) ||
2
Assuming 'I' is not a 'LoadInst'
3
Assuming 'I' is not a 'StoreInst'
4
Assuming 'I' is not a 'CallInst'
17
Returning the value 1, which participates in a condition later
1084 isa<FenceInst>(I) || isa<CastInst>(I) ||
5
Assuming 'I' is not a 'FenceInst'
6
Assuming 'I' is not a 'CastInst'
1085 isa<UnaryOperator>(I) || isa<BinaryOperator>(I) ||
7
Assuming 'I' is not a 'UnaryOperator'
8
Assuming 'I' is not a 'BinaryOperator'
1086 isa<SelectInst>(I) || isa<GetElementPtrInst>(I) || isa<CmpInst>(I) ||
9
Assuming 'I' is not a 'SelectInst'
10
Assuming 'I' is not a 'GetElementPtrInst'
11
Assuming 'I' is not a 'CmpInst'
1087 isa<InsertElementInst>(I) || isa<ExtractElementInst>(I) ||
12
Assuming 'I' is not a 'InsertElementInst'
13
Assuming 'I' is not a 'ExtractElementInst'
1088 isa<ShuffleVectorInst>(I) || isa<ExtractValueInst>(I) ||
14
Assuming 'I' is not a 'ShuffleVectorInst'
15
Assuming 'I' is not a 'ExtractValueInst'
1089 isa<InsertValueInst>(I));
16
Assuming 'I' is a 'InsertValueInst'
1090}
1091/// Return true if all of the alias sets within this AST are known not to
1092/// contain a Mod, or if MSSA knows thare are no MemoryDefs in the loop.
1093bool isReadOnly(AliasSetTracker *CurAST, const MemorySSAUpdater *MSSAU,
1094 const Loop *L) {
1095 if (CurAST) {
1096 for (AliasSet &AS : *CurAST) {
1097 if (!AS.isForwardingAliasSet() && AS.isMod()) {
1098 return false;
1099 }
1100 }
1101 return true;
1102 } else { /*MSSAU*/
1103 for (auto *BB : L->getBlocks())
1104 if (MSSAU->getMemorySSA()->getBlockDefs(BB))
1105 return false;
1106 return true;
1107 }
1108}
1109
1110/// Return true if I is the only Instruction with a MemoryAccess in L.
1111bool isOnlyMemoryAccess(const Instruction *I, const Loop *L,
1112 const MemorySSAUpdater *MSSAU) {
1113 for (auto *BB : L->getBlocks())
1114 if (auto *Accs = MSSAU->getMemorySSA()->getBlockAccesses(BB)) {
1115 int NotAPhi = 0;
1116 for (const auto &Acc : *Accs) {
1117 if (isa<MemoryPhi>(&Acc))
1118 continue;
1119 const auto *MUD = cast<MemoryUseOrDef>(&Acc);
1120 if (MUD->getMemoryInst() != I || NotAPhi++ == 1)
1121 return false;
1122 }
1123 }
1124 return true;
1125}
1126}
1127
1128bool llvm::canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
1129 Loop *CurLoop, AliasSetTracker *CurAST,
1130 MemorySSAUpdater *MSSAU,
1131 bool TargetExecutesOncePerLoop,
1132 SinkAndHoistLICMFlags *Flags,
1133 OptimizationRemarkEmitter *ORE) {
1134 // If we don't understand the instruction, bail early.
1135 if (!isHoistableAndSinkableInst(I))
1
Calling 'isHoistableAndSinkableInst'
18
Returning from 'isHoistableAndSinkableInst'
19
Taking false branch
1136 return false;
1137
1138 MemorySSA *MSSA = MSSAU ? MSSAU->getMemorySSA() : nullptr;
20
Assuming 'MSSAU' is null
21
'?' condition is false
22
'MSSA' initialized to a null pointer value
1139 if (MSSA
22.1
'MSSA' is null
22.1
'MSSA' is null
22.1
'MSSA' is null
22.1
'MSSA' is null
)
23
Taking false branch
1140 assert(Flags != nullptr && "Flags cannot be null.")((Flags != nullptr && "Flags cannot be null.") ? static_cast
<void> (0) : __assert_fail ("Flags != nullptr && \"Flags cannot be null.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1140, __PRETTY_FUNCTION__))
;
1141
1142 // Loads have extra constraints we have to verify before we can hoist them.
1143 if (LoadInst *LI
24.1
'LI' is null
24.1
'LI' is null
24.1
'LI' is null
24.1
'LI' is null
= dyn_cast<LoadInst>(&I)) {
24
Assuming the object is not a 'LoadInst'
25
Taking false branch
1144 if (!LI->isUnordered())
1145 return false; // Don't sink/hoist volatile or ordered atomic loads!
1146
1147 // Loads from constant memory are always safe to move, even if they end up
1148 // in the same alias set as something that ends up being modified.
1149 if (AA->pointsToConstantMemory(LI->getOperand(0)))
1150 return true;
1151 if (LI->hasMetadata(LLVMContext::MD_invariant_load))
1152 return true;
1153
1154 if (LI->isAtomic() && !TargetExecutesOncePerLoop)
1155 return false; // Don't risk duplicating unordered loads
1156
1157 // This checks for an invariant.start dominating the load.
1158 if (isLoadInvariantInLoop(LI, DT, CurLoop))
1159 return true;
1160
1161 bool Invalidated;
1162 if (CurAST)
1163 Invalidated = pointerInvalidatedByLoop(MemoryLocation::get(LI), CurAST,
1164 CurLoop, AA);
1165 else
1166 Invalidated = pointerInvalidatedByLoopWithMSSA(
1167 MSSA, cast<MemoryUse>(MSSA->getMemoryAccess(LI)), CurLoop, *Flags);
1168 // Check loop-invariant address because this may also be a sinkable load
1169 // whose address is not necessarily loop-invariant.
1170 if (ORE && Invalidated && CurLoop->isLoopInvariant(LI->getPointerOperand()))
1171 ORE->emit([&]() {
1172 return OptimizationRemarkMissed(
1173 DEBUG_TYPE"licm", "LoadWithLoopInvariantAddressInvalidated", LI)
1174 << "failed to move load with loop-invariant address "
1175 "because the loop may invalidate its value";
1176 });
1177
1178 return !Invalidated;
1179 } else if (CallInst *CI
26.1
'CI' is non-null
26.1
'CI' is non-null
26.1
'CI' is non-null
26.1
'CI' is non-null
= dyn_cast<CallInst>(&I)) {
26
Assuming the object is a 'CallInst'
27
Taking true branch
1180 // Don't sink or hoist dbg info; it's legal, but not useful.
1181 if (isa<DbgInfoIntrinsic>(I))
28
Assuming 'I' is not a 'DbgInfoIntrinsic'
29
Taking false branch
1182 return false;
1183
1184 // Don't sink calls which can throw.
1185 if (CI->mayThrow())
30
Assuming the condition is false
31
Taking false branch
1186 return false;
1187
1188 using namespace PatternMatch;
1189 if (match(CI, m_Intrinsic<Intrinsic::assume>()))
32
Calling 'match<llvm::CallInst, llvm::PatternMatch::IntrinsicID_match>'
39
Returning from 'match<llvm::CallInst, llvm::PatternMatch::IntrinsicID_match>'
40
Taking false branch
1190 // Assumes don't actually alias anything or throw
1191 return true;
1192
1193 if (match(CI, m_Intrinsic<Intrinsic::experimental_widenable_condition>()))
41
Calling 'match<llvm::CallInst, llvm::PatternMatch::IntrinsicID_match>'
48
Returning from 'match<llvm::CallInst, llvm::PatternMatch::IntrinsicID_match>'
49
Taking false branch
1194 // Widenable conditions don't actually alias anything or throw
1195 return true;
1196
1197 // Handle simple cases by querying alias analysis.
1198 FunctionModRefBehavior Behavior = AA->getModRefBehavior(CI);
1199 if (Behavior == FMRB_DoesNotAccessMemory)
50
Assuming 'Behavior' is not equal to FMRB_DoesNotAccessMemory
51
Taking false branch
1200 return true;
1201 if (AliasAnalysis::onlyReadsMemory(Behavior)) {
52
Calling 'AAResults::onlyReadsMemory'
55
Returning from 'AAResults::onlyReadsMemory'
56
Taking true branch
1202 // A readonly argmemonly function only reads from memory pointed to by
1203 // it's arguments with arbitrary offsets. If we can prove there are no
1204 // writes to this memory in the loop, we can hoist or sink.
1205 if (AliasAnalysis::onlyAccessesArgPointees(Behavior)) {
57
Calling 'AAResults::onlyAccessesArgPointees'
60
Returning from 'AAResults::onlyAccessesArgPointees'
61
Taking true branch
1206 // TODO: expand to writeable arguments
1207 for (Value *Op : CI->arg_operands())
62
Assuming '__begin5' is not equal to '__end5'
1208 if (Op->getType()->isPointerTy()) {
63
Calling 'Type::isPointerTy'
66
Returning from 'Type::isPointerTy'
67
Taking true branch
1209 bool Invalidated;
1210 if (CurAST)
68
Assuming 'CurAST' is null
69
Taking false branch
1211 Invalidated = pointerInvalidatedByLoop(
1212 MemoryLocation(Op, LocationSize::unknown(), AAMDNodes()),
1213 CurAST, CurLoop, AA);
1214 else
1215 Invalidated = pointerInvalidatedByLoopWithMSSA(
1216 MSSA, cast<MemoryUse>(MSSA->getMemoryAccess(CI)), CurLoop,
70
Called C++ object pointer is null
1217 *Flags);
1218 if (Invalidated)
1219 return false;
1220 }
1221 return true;
1222 }
1223
1224 // If this call only reads from memory and there are no writes to memory
1225 // in the loop, we can hoist or sink the call as appropriate.
1226 if (isReadOnly(CurAST, MSSAU, CurLoop))
1227 return true;
1228 }
1229
1230 // FIXME: This should use mod/ref information to see if we can hoist or
1231 // sink the call.
1232
1233 return false;
1234 } else if (auto *FI = dyn_cast<FenceInst>(&I)) {
1235 // Fences alias (most) everything to provide ordering. For the moment,
1236 // just give up if there are any other memory operations in the loop.
1237 if (CurAST) {
1238 auto Begin = CurAST->begin();
1239 assert(Begin != CurAST->end() && "must contain FI")((Begin != CurAST->end() && "must contain FI") ? static_cast
<void> (0) : __assert_fail ("Begin != CurAST->end() && \"must contain FI\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1239, __PRETTY_FUNCTION__))
;
1240 if (std::next(Begin) != CurAST->end())
1241 // constant memory for instance, TODO: handle better
1242 return false;
1243 auto *UniqueI = Begin->getUniqueInstruction();
1244 if (!UniqueI)
1245 // other memory op, give up
1246 return false;
1247 (void)FI; // suppress unused variable warning
1248 assert(UniqueI == FI && "AS must contain FI")((UniqueI == FI && "AS must contain FI") ? static_cast
<void> (0) : __assert_fail ("UniqueI == FI && \"AS must contain FI\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1248, __PRETTY_FUNCTION__))
;
1249 return true;
1250 } else // MSSAU
1251 return isOnlyMemoryAccess(FI, CurLoop, MSSAU);
1252 } else if (auto *SI = dyn_cast<StoreInst>(&I)) {
1253 if (!SI->isUnordered())
1254 return false; // Don't sink/hoist volatile or ordered atomic store!
1255
1256 // We can only hoist a store that we can prove writes a value which is not
1257 // read or overwritten within the loop. For those cases, we fallback to
1258 // load store promotion instead. TODO: We can extend this to cases where
1259 // there is exactly one write to the location and that write dominates an
1260 // arbitrary number of reads in the loop.
1261 if (CurAST) {
1262 auto &AS = CurAST->getAliasSetFor(MemoryLocation::get(SI));
1263
1264 if (AS.isRef() || !AS.isMustAlias())
1265 // Quick exit test, handled by the full path below as well.
1266 return false;
1267 auto *UniqueI = AS.getUniqueInstruction();
1268 if (!UniqueI)
1269 // other memory op, give up
1270 return false;
1271 assert(UniqueI == SI && "AS must contain SI")((UniqueI == SI && "AS must contain SI") ? static_cast
<void> (0) : __assert_fail ("UniqueI == SI && \"AS must contain SI\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1271, __PRETTY_FUNCTION__))
;
1272 return true;
1273 } else { // MSSAU
1274 if (isOnlyMemoryAccess(SI, CurLoop, MSSAU))
1275 return true;
1276 // If there are more accesses than the Promotion cap, give up, we're not
1277 // walking a list that long.
1278 if (Flags->NoOfMemAccTooLarge)
1279 return false;
1280 // Check store only if there's still "quota" to check clobber.
1281 if (Flags->LicmMssaOptCounter >= Flags->LicmMssaOptCap)
1282 return false;
1283 // If there are interfering Uses (i.e. their defining access is in the
1284 // loop), or ordered loads (stored as Defs!), don't move this store.
1285 // Could do better here, but this is conservatively correct.
1286 // TODO: Cache set of Uses on the first walk in runOnLoop, update when
1287 // moving accesses. Can also extend to dominating uses.
1288 auto *SIMD = MSSA->getMemoryAccess(SI);
1289 for (auto *BB : CurLoop->getBlocks())
1290 if (auto *Accesses = MSSA->getBlockAccesses(BB)) {
1291 for (const auto &MA : *Accesses)
1292 if (const auto *MU = dyn_cast<MemoryUse>(&MA)) {
1293 auto *MD = MU->getDefiningAccess();
1294 if (!MSSA->isLiveOnEntryDef(MD) &&
1295 CurLoop->contains(MD->getBlock()))
1296 return false;
1297 // Disable hoisting past potentially interfering loads. Optimized
1298 // Uses may point to an access outside the loop, as getClobbering
1299 // checks the previous iteration when walking the backedge.
1300 // FIXME: More precise: no Uses that alias SI.
1301 if (!Flags->IsSink && !MSSA->dominates(SIMD, MU))
1302 return false;
1303 } else if (const auto *MD = dyn_cast<MemoryDef>(&MA)) {
1304 if (auto *LI = dyn_cast<LoadInst>(MD->getMemoryInst())) {
1305 (void)LI; // Silence warning.
1306 assert(!LI->isUnordered() && "Expected unordered load")((!LI->isUnordered() && "Expected unordered load")
? static_cast<void> (0) : __assert_fail ("!LI->isUnordered() && \"Expected unordered load\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1306, __PRETTY_FUNCTION__))
;
1307 return false;
1308 }
1309 // Any call, while it may not be clobbering SI, it may be a use.
1310 if (auto *CI = dyn_cast<CallInst>(MD->getMemoryInst())) {
1311 // Check if the call may read from the memory locattion written
1312 // to by SI. Check CI's attributes and arguments; the number of
1313 // such checks performed is limited above by NoOfMemAccTooLarge.
1314 ModRefInfo MRI = AA->getModRefInfo(CI, MemoryLocation::get(SI));
1315 if (isModOrRefSet(MRI))
1316 return false;
1317 }
1318 }
1319 }
1320
1321 auto *Source = MSSA->getSkipSelfWalker()->getClobberingMemoryAccess(SI);
1322 Flags->LicmMssaOptCounter++;
1323 // If there are no clobbering Defs in the loop, store is safe to hoist.
1324 return MSSA->isLiveOnEntryDef(Source) ||
1325 !CurLoop->contains(Source->getBlock());
1326 }
1327 }
1328
1329 assert(!I.mayReadOrWriteMemory() && "unhandled aliasing")((!I.mayReadOrWriteMemory() && "unhandled aliasing") ?
static_cast<void> (0) : __assert_fail ("!I.mayReadOrWriteMemory() && \"unhandled aliasing\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1329, __PRETTY_FUNCTION__))
;
1330
1331 // We've established mechanical ability and aliasing, it's up to the caller
1332 // to check fault safety
1333 return true;
1334}
1335
1336/// Returns true if a PHINode is a trivially replaceable with an
1337/// Instruction.
1338/// This is true when all incoming values are that instruction.
1339/// This pattern occurs most often with LCSSA PHI nodes.
1340///
1341static bool isTriviallyReplaceablePHI(const PHINode &PN, const Instruction &I) {
1342 for (const Value *IncValue : PN.incoming_values())
1343 if (IncValue != &I)
1344 return false;
1345
1346 return true;
1347}
1348
1349/// Return true if the instruction is free in the loop.
1350static bool isFreeInLoop(const Instruction &I, const Loop *CurLoop,
1351 const TargetTransformInfo *TTI) {
1352
1353 if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&I)) {
1354 if (TTI->getUserCost(GEP) != TargetTransformInfo::TCC_Free)
1355 return false;
1356 // For a GEP, we cannot simply use getUserCost because currently it
1357 // optimistically assume that a GEP will fold into addressing mode
1358 // regardless of its users.
1359 const BasicBlock *BB = GEP->getParent();
1360 for (const User *U : GEP->users()) {
1361 const Instruction *UI = cast<Instruction>(U);
1362 if (CurLoop->contains(UI) &&
1363 (BB != UI->getParent() ||
1364 (!isa<StoreInst>(UI) && !isa<LoadInst>(UI))))
1365 return false;
1366 }
1367 return true;
1368 } else
1369 return TTI->getUserCost(&I) == TargetTransformInfo::TCC_Free;
1370}
1371
1372/// Return true if the only users of this instruction are outside of
1373/// the loop. If this is true, we can sink the instruction to the exit
1374/// blocks of the loop.
1375///
1376/// We also return true if the instruction could be folded away in lowering.
1377/// (e.g., a GEP can be folded into a load as an addressing mode in the loop).
1378static bool isNotUsedOrFreeInLoop(const Instruction &I, const Loop *CurLoop,
1379 const LoopSafetyInfo *SafetyInfo,
1380 TargetTransformInfo *TTI, bool &FreeInLoop) {
1381 const auto &BlockColors = SafetyInfo->getBlockColors();
1382 bool IsFree = isFreeInLoop(I, CurLoop, TTI);
1383 for (const User *U : I.users()) {
1384 const Instruction *UI = cast<Instruction>(U);
1385 if (const PHINode *PN = dyn_cast<PHINode>(UI)) {
1386 const BasicBlock *BB = PN->getParent();
1387 // We cannot sink uses in catchswitches.
1388 if (isa<CatchSwitchInst>(BB->getTerminator()))
1389 return false;
1390
1391 // We need to sink a callsite to a unique funclet. Avoid sinking if the
1392 // phi use is too muddled.
1393 if (isa<CallInst>(I))
1394 if (!BlockColors.empty() &&
1395 BlockColors.find(const_cast<BasicBlock *>(BB))->second.size() != 1)
1396 return false;
1397 }
1398
1399 if (CurLoop->contains(UI)) {
1400 if (IsFree) {
1401 FreeInLoop = true;
1402 continue;
1403 }
1404 return false;
1405 }
1406 }
1407 return true;
1408}
1409
1410static Instruction *CloneInstructionInExitBlock(
1411 Instruction &I, BasicBlock &ExitBlock, PHINode &PN, const LoopInfo *LI,
1412 const LoopSafetyInfo *SafetyInfo, MemorySSAUpdater *MSSAU) {
1413 Instruction *New;
1414 if (auto *CI = dyn_cast<CallInst>(&I)) {
1415 const auto &BlockColors = SafetyInfo->getBlockColors();
1416
1417 // Sinking call-sites need to be handled differently from other
1418 // instructions. The cloned call-site needs a funclet bundle operand
1419 // appropriate for its location in the CFG.
1420 SmallVector<OperandBundleDef, 1> OpBundles;
1421 for (unsigned BundleIdx = 0, BundleEnd = CI->getNumOperandBundles();
1422 BundleIdx != BundleEnd; ++BundleIdx) {
1423 OperandBundleUse Bundle = CI->getOperandBundleAt(BundleIdx);
1424 if (Bundle.getTagID() == LLVMContext::OB_funclet)
1425 continue;
1426
1427 OpBundles.emplace_back(Bundle);
1428 }
1429
1430 if (!BlockColors.empty()) {
1431 const ColorVector &CV = BlockColors.find(&ExitBlock)->second;
1432 assert(CV.size() == 1 && "non-unique color for exit block!")((CV.size() == 1 && "non-unique color for exit block!"
) ? static_cast<void> (0) : __assert_fail ("CV.size() == 1 && \"non-unique color for exit block!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1432, __PRETTY_FUNCTION__))
;
1433 BasicBlock *BBColor = CV.front();
1434 Instruction *EHPad = BBColor->getFirstNonPHI();
1435 if (EHPad->isEHPad())
1436 OpBundles.emplace_back("funclet", EHPad);
1437 }
1438
1439 New = CallInst::Create(CI, OpBundles);
1440 } else {
1441 New = I.clone();
1442 }
1443
1444 ExitBlock.getInstList().insert(ExitBlock.getFirstInsertionPt(), New);
1445 if (!I.getName().empty())
1446 New->setName(I.getName() + ".le");
1447
1448 if (MSSAU && MSSAU->getMemorySSA()->getMemoryAccess(&I)) {
1449 // Create a new MemoryAccess and let MemorySSA set its defining access.
1450 MemoryAccess *NewMemAcc = MSSAU->createMemoryAccessInBB(
1451 New, nullptr, New->getParent(), MemorySSA::Beginning);
1452 if (NewMemAcc) {
1453 if (auto *MemDef = dyn_cast<MemoryDef>(NewMemAcc))
1454 MSSAU->insertDef(MemDef, /*RenameUses=*/true);
1455 else {
1456 auto *MemUse = cast<MemoryUse>(NewMemAcc);
1457 MSSAU->insertUse(MemUse, /*RenameUses=*/true);
1458 }
1459 }
1460 }
1461
1462 // Build LCSSA PHI nodes for any in-loop operands. Note that this is
1463 // particularly cheap because we can rip off the PHI node that we're
1464 // replacing for the number and blocks of the predecessors.
1465 // OPT: If this shows up in a profile, we can instead finish sinking all
1466 // invariant instructions, and then walk their operands to re-establish
1467 // LCSSA. That will eliminate creating PHI nodes just to nuke them when
1468 // sinking bottom-up.
1469 for (User::op_iterator OI = New->op_begin(), OE = New->op_end(); OI != OE;
1470 ++OI)
1471 if (Instruction *OInst = dyn_cast<Instruction>(*OI))
1472 if (Loop *OLoop = LI->getLoopFor(OInst->getParent()))
1473 if (!OLoop->contains(&PN)) {
1474 PHINode *OpPN =
1475 PHINode::Create(OInst->getType(), PN.getNumIncomingValues(),
1476 OInst->getName() + ".lcssa", &ExitBlock.front());
1477 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
1478 OpPN->addIncoming(OInst, PN.getIncomingBlock(i));
1479 *OI = OpPN;
1480 }
1481 return New;
1482}
1483
1484static void eraseInstruction(Instruction &I, ICFLoopSafetyInfo &SafetyInfo,
1485 AliasSetTracker *AST, MemorySSAUpdater *MSSAU) {
1486 if (AST)
1487 AST->deleteValue(&I);
1488 if (MSSAU)
1489 MSSAU->removeMemoryAccess(&I);
1490 SafetyInfo.removeInstruction(&I);
1491 I.eraseFromParent();
1492}
1493
1494static void moveInstructionBefore(Instruction &I, Instruction &Dest,
1495 ICFLoopSafetyInfo &SafetyInfo,
1496 MemorySSAUpdater *MSSAU,
1497 ScalarEvolution *SE) {
1498 SafetyInfo.removeInstruction(&I);
1499 SafetyInfo.insertInstructionTo(&I, Dest.getParent());
1500 I.moveBefore(&Dest);
1501 if (MSSAU)
1502 if (MemoryUseOrDef *OldMemAcc = cast_or_null<MemoryUseOrDef>(
1503 MSSAU->getMemorySSA()->getMemoryAccess(&I)))
1504 MSSAU->moveToPlace(OldMemAcc, Dest.getParent(),
1505 MemorySSA::BeforeTerminator);
1506 if (SE)
1507 SE->forgetValue(&I);
1508}
1509
1510static Instruction *sinkThroughTriviallyReplaceablePHI(
1511 PHINode *TPN, Instruction *I, LoopInfo *LI,
1512 SmallDenseMap<BasicBlock *, Instruction *, 32> &SunkCopies,
1513 const LoopSafetyInfo *SafetyInfo, const Loop *CurLoop,
1514 MemorySSAUpdater *MSSAU) {
1515 assert(isTriviallyReplaceablePHI(*TPN, *I) &&((isTriviallyReplaceablePHI(*TPN, *I) && "Expect only trivially replaceable PHI"
) ? static_cast<void> (0) : __assert_fail ("isTriviallyReplaceablePHI(*TPN, *I) && \"Expect only trivially replaceable PHI\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1516, __PRETTY_FUNCTION__))
1516 "Expect only trivially replaceable PHI")((isTriviallyReplaceablePHI(*TPN, *I) && "Expect only trivially replaceable PHI"
) ? static_cast<void> (0) : __assert_fail ("isTriviallyReplaceablePHI(*TPN, *I) && \"Expect only trivially replaceable PHI\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1516, __PRETTY_FUNCTION__))
;
1517 BasicBlock *ExitBlock = TPN->getParent();
1518 Instruction *New;
1519 auto It = SunkCopies.find(ExitBlock);
1520 if (It != SunkCopies.end())
1521 New = It->second;
1522 else
1523 New = SunkCopies[ExitBlock] = CloneInstructionInExitBlock(
1524 *I, *ExitBlock, *TPN, LI, SafetyInfo, MSSAU);
1525 return New;
1526}
1527
1528static bool canSplitPredecessors(PHINode *PN, LoopSafetyInfo *SafetyInfo) {
1529 BasicBlock *BB = PN->getParent();
1530 if (!BB->canSplitPredecessors())
1531 return false;
1532 // It's not impossible to split EHPad blocks, but if BlockColors already exist
1533 // it require updating BlockColors for all offspring blocks accordingly. By
1534 // skipping such corner case, we can make updating BlockColors after splitting
1535 // predecessor fairly simple.
1536 if (!SafetyInfo->getBlockColors().empty() && BB->getFirstNonPHI()->isEHPad())
1537 return false;
1538 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
1539 BasicBlock *BBPred = *PI;
1540 if (isa<IndirectBrInst>(BBPred->getTerminator()))
1541 return false;
1542 }
1543 return true;
1544}
1545
1546static void splitPredecessorsOfLoopExit(PHINode *PN, DominatorTree *DT,
1547 LoopInfo *LI, const Loop *CurLoop,
1548 LoopSafetyInfo *SafetyInfo,
1549 MemorySSAUpdater *MSSAU) {
1550#ifndef NDEBUG
1551 SmallVector<BasicBlock *, 32> ExitBlocks;
1552 CurLoop->getUniqueExitBlocks(ExitBlocks);
1553 SmallPtrSet<BasicBlock *, 32> ExitBlockSet(ExitBlocks.begin(),
1554 ExitBlocks.end());
1555#endif
1556 BasicBlock *ExitBB = PN->getParent();
1557 assert(ExitBlockSet.count(ExitBB) && "Expect the PHI is in an exit block.")((ExitBlockSet.count(ExitBB) && "Expect the PHI is in an exit block."
) ? static_cast<void> (0) : __assert_fail ("ExitBlockSet.count(ExitBB) && \"Expect the PHI is in an exit block.\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1557, __PRETTY_FUNCTION__))
;
1558
1559 // Split predecessors of the loop exit to make instructions in the loop are
1560 // exposed to exit blocks through trivially replaceable PHIs while keeping the
1561 // loop in the canonical form where each predecessor of each exit block should
1562 // be contained within the loop. For example, this will convert the loop below
1563 // from
1564 //
1565 // LB1:
1566 // %v1 =
1567 // br %LE, %LB2
1568 // LB2:
1569 // %v2 =
1570 // br %LE, %LB1
1571 // LE:
1572 // %p = phi [%v1, %LB1], [%v2, %LB2] <-- non-trivially replaceable
1573 //
1574 // to
1575 //
1576 // LB1:
1577 // %v1 =
1578 // br %LE.split, %LB2
1579 // LB2:
1580 // %v2 =
1581 // br %LE.split2, %LB1
1582 // LE.split:
1583 // %p1 = phi [%v1, %LB1] <-- trivially replaceable
1584 // br %LE
1585 // LE.split2:
1586 // %p2 = phi [%v2, %LB2] <-- trivially replaceable
1587 // br %LE
1588 // LE:
1589 // %p = phi [%p1, %LE.split], [%p2, %LE.split2]
1590 //
1591 const auto &BlockColors = SafetyInfo->getBlockColors();
1592 SmallSetVector<BasicBlock *, 8> PredBBs(pred_begin(ExitBB), pred_end(ExitBB));
1593 while (!PredBBs.empty()) {
1594 BasicBlock *PredBB = *PredBBs.begin();
1595 assert(CurLoop->contains(PredBB) &&((CurLoop->contains(PredBB) && "Expect all predecessors are in the loop"
) ? static_cast<void> (0) : __assert_fail ("CurLoop->contains(PredBB) && \"Expect all predecessors are in the loop\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1596, __PRETTY_FUNCTION__))
1596 "Expect all predecessors are in the loop")((CurLoop->contains(PredBB) && "Expect all predecessors are in the loop"
) ? static_cast<void> (0) : __assert_fail ("CurLoop->contains(PredBB) && \"Expect all predecessors are in the loop\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1596, __PRETTY_FUNCTION__))
;
1597 if (PN->getBasicBlockIndex(PredBB) >= 0) {
1598 BasicBlock *NewPred = SplitBlockPredecessors(
1599 ExitBB, PredBB, ".split.loop.exit", DT, LI, MSSAU, true);
1600 // Since we do not allow splitting EH-block with BlockColors in
1601 // canSplitPredecessors(), we can simply assign predecessor's color to
1602 // the new block.
1603 if (!BlockColors.empty())
1604 // Grab a reference to the ColorVector to be inserted before getting the
1605 // reference to the vector we are copying because inserting the new
1606 // element in BlockColors might cause the map to be reallocated.
1607 SafetyInfo->copyColors(NewPred, PredBB);
1608 }
1609 PredBBs.remove(PredBB);
1610 }
1611}
1612
1613/// When an instruction is found to only be used outside of the loop, this
1614/// function moves it to the exit blocks and patches up SSA form as needed.
1615/// This method is guaranteed to remove the original instruction from its
1616/// position, and may either delete it or move it to outside of the loop.
1617///
1618static bool sink(Instruction &I, LoopInfo *LI, DominatorTree *DT,
1619 const Loop *CurLoop, ICFLoopSafetyInfo *SafetyInfo,
1620 MemorySSAUpdater *MSSAU, OptimizationRemarkEmitter *ORE) {
1621 LLVM_DEBUG(dbgs() << "LICM sinking instruction: " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM sinking instruction: " <<
I << "\n"; } } while (false)
;
1622 ORE->emit([&]() {
1623 return OptimizationRemark(DEBUG_TYPE"licm", "InstSunk", &I)
1624 << "sinking " << ore::NV("Inst", &I);
1625 });
1626 bool Changed = false;
1627 if (isa<LoadInst>(I))
1628 ++NumMovedLoads;
1629 else if (isa<CallInst>(I))
1630 ++NumMovedCalls;
1631 ++NumSunk;
1632
1633 // Iterate over users to be ready for actual sinking. Replace users via
1634 // unreachable blocks with undef and make all user PHIs trivially replaceable.
1635 SmallPtrSet<Instruction *, 8> VisitedUsers;
1636 for (Value::user_iterator UI = I.user_begin(), UE = I.user_end(); UI != UE;) {
1637 auto *User = cast<Instruction>(*UI);
1638 Use &U = UI.getUse();
1639 ++UI;
1640
1641 if (VisitedUsers.count(User) || CurLoop->contains(User))
1642 continue;
1643
1644 if (!DT->isReachableFromEntry(User->getParent())) {
1645 U = UndefValue::get(I.getType());
1646 Changed = true;
1647 continue;
1648 }
1649
1650 // The user must be a PHI node.
1651 PHINode *PN = cast<PHINode>(User);
1652
1653 // Surprisingly, instructions can be used outside of loops without any
1654 // exits. This can only happen in PHI nodes if the incoming block is
1655 // unreachable.
1656 BasicBlock *BB = PN->getIncomingBlock(U);
1657 if (!DT->isReachableFromEntry(BB)) {
1658 U = UndefValue::get(I.getType());
1659 Changed = true;
1660 continue;
1661 }
1662
1663 VisitedUsers.insert(PN);
1664 if (isTriviallyReplaceablePHI(*PN, I))
1665 continue;
1666
1667 if (!canSplitPredecessors(PN, SafetyInfo))
1668 return Changed;
1669
1670 // Split predecessors of the PHI so that we can make users trivially
1671 // replaceable.
1672 splitPredecessorsOfLoopExit(PN, DT, LI, CurLoop, SafetyInfo, MSSAU);
1673
1674 // Should rebuild the iterators, as they may be invalidated by
1675 // splitPredecessorsOfLoopExit().
1676 UI = I.user_begin();
1677 UE = I.user_end();
1678 }
1679
1680 if (VisitedUsers.empty())
1681 return Changed;
1682
1683#ifndef NDEBUG
1684 SmallVector<BasicBlock *, 32> ExitBlocks;
1685 CurLoop->getUniqueExitBlocks(ExitBlocks);
1686 SmallPtrSet<BasicBlock *, 32> ExitBlockSet(ExitBlocks.begin(),
1687 ExitBlocks.end());
1688#endif
1689
1690 // Clones of this instruction. Don't create more than one per exit block!
1691 SmallDenseMap<BasicBlock *, Instruction *, 32> SunkCopies;
1692
1693 // If this instruction is only used outside of the loop, then all users are
1694 // PHI nodes in exit blocks due to LCSSA form. Just RAUW them with clones of
1695 // the instruction.
1696 SmallSetVector<User*, 8> Users(I.user_begin(), I.user_end());
1697 for (auto *UI : Users) {
1698 auto *User = cast<Instruction>(UI);
1699
1700 if (CurLoop->contains(User))
1701 continue;
1702
1703 PHINode *PN = cast<PHINode>(User);
1704 assert(ExitBlockSet.count(PN->getParent()) &&((ExitBlockSet.count(PN->getParent()) && "The LCSSA PHI is not in an exit block!"
) ? static_cast<void> (0) : __assert_fail ("ExitBlockSet.count(PN->getParent()) && \"The LCSSA PHI is not in an exit block!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1705, __PRETTY_FUNCTION__))
1705 "The LCSSA PHI is not in an exit block!")((ExitBlockSet.count(PN->getParent()) && "The LCSSA PHI is not in an exit block!"
) ? static_cast<void> (0) : __assert_fail ("ExitBlockSet.count(PN->getParent()) && \"The LCSSA PHI is not in an exit block!\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1705, __PRETTY_FUNCTION__))
;
1706 // The PHI must be trivially replaceable.
1707 Instruction *New = sinkThroughTriviallyReplaceablePHI(
1708 PN, &I, LI, SunkCopies, SafetyInfo, CurLoop, MSSAU);
1709 PN->replaceAllUsesWith(New);
1710 eraseInstruction(*PN, *SafetyInfo, nullptr, nullptr);
1711 Changed = true;
1712 }
1713 return Changed;
1714}
1715
1716/// When an instruction is found to only use loop invariant operands that
1717/// is safe to hoist, this instruction is called to do the dirty work.
1718///
1719static void hoist(Instruction &I, const DominatorTree *DT, const Loop *CurLoop,
1720 BasicBlock *Dest, ICFLoopSafetyInfo *SafetyInfo,
1721 MemorySSAUpdater *MSSAU, ScalarEvolution *SE,
1722 OptimizationRemarkEmitter *ORE) {
1723 LLVM_DEBUG(dbgs() << "LICM hoisting to " << Dest->getName() << ": " << Ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM hoisting to " << Dest
->getName() << ": " << I << "\n"; } } while
(false)
1724 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM hoisting to " << Dest
->getName() << ": " << I << "\n"; } } while
(false)
;
1725 ORE->emit([&]() {
1726 return OptimizationRemark(DEBUG_TYPE"licm", "Hoisted", &I) << "hoisting "
1727 << ore::NV("Inst", &I);
1728 });
1729
1730 // Metadata can be dependent on conditions we are hoisting above.
1731 // Conservatively strip all metadata on the instruction unless we were
1732 // guaranteed to execute I if we entered the loop, in which case the metadata
1733 // is valid in the loop preheader.
1734 if (I.hasMetadataOtherThanDebugLoc() &&
1735 // The check on hasMetadataOtherThanDebugLoc is to prevent us from burning
1736 // time in isGuaranteedToExecute if we don't actually have anything to
1737 // drop. It is a compile time optimization, not required for correctness.
1738 !SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop))
1739 I.dropUnknownNonDebugMetadata();
1740
1741 if (isa<PHINode>(I))
1742 // Move the new node to the end of the phi list in the destination block.
1743 moveInstructionBefore(I, *Dest->getFirstNonPHI(), *SafetyInfo, MSSAU, SE);
1744 else
1745 // Move the new node to the destination block, before its terminator.
1746 moveInstructionBefore(I, *Dest->getTerminator(), *SafetyInfo, MSSAU, SE);
1747
1748 // Apply line 0 debug locations when we are moving instructions to different
1749 // basic blocks because we want to avoid jumpy line tables.
1750 if (const DebugLoc &DL = I.getDebugLoc())
1751 I.setDebugLoc(DebugLoc::get(0, 0, DL.getScope(), DL.getInlinedAt()));
1752
1753 if (isa<LoadInst>(I))
1754 ++NumMovedLoads;
1755 else if (isa<CallInst>(I))
1756 ++NumMovedCalls;
1757 ++NumHoisted;
1758}
1759
1760/// Only sink or hoist an instruction if it is not a trapping instruction,
1761/// or if the instruction is known not to trap when moved to the preheader.
1762/// or if it is a trapping instruction and is guaranteed to execute.
1763static bool isSafeToExecuteUnconditionally(Instruction &Inst,
1764 const DominatorTree *DT,
1765 const Loop *CurLoop,
1766 const LoopSafetyInfo *SafetyInfo,
1767 OptimizationRemarkEmitter *ORE,
1768 const Instruction *CtxI) {
1769 if (isSafeToSpeculativelyExecute(&Inst, CtxI, DT))
1770 return true;
1771
1772 bool GuaranteedToExecute =
1773 SafetyInfo->isGuaranteedToExecute(Inst, DT, CurLoop);
1774
1775 if (!GuaranteedToExecute) {
1776 auto *LI = dyn_cast<LoadInst>(&Inst);
1777 if (LI && CurLoop->isLoopInvariant(LI->getPointerOperand()))
1778 ORE->emit([&]() {
1779 return OptimizationRemarkMissed(
1780 DEBUG_TYPE"licm", "LoadWithLoopInvariantAddressCondExecuted", LI)
1781 << "failed to hoist load with loop-invariant address "
1782 "because load is conditionally executed";
1783 });
1784 }
1785
1786 return GuaranteedToExecute;
1787}
1788
1789namespace {
1790class LoopPromoter : public LoadAndStorePromoter {
1791 Value *SomePtr; // Designated pointer to store to.
1792 const SmallSetVector<Value *, 8> &PointerMustAliases;
1793 SmallVectorImpl<BasicBlock *> &LoopExitBlocks;
1794 SmallVectorImpl<Instruction *> &LoopInsertPts;
1795 SmallVectorImpl<MemoryAccess *> &MSSAInsertPts;
1796 PredIteratorCache &PredCache;
1797 AliasSetTracker &AST;
1798 MemorySSAUpdater *MSSAU;
1799 LoopInfo &LI;
1800 DebugLoc DL;
1801 int Alignment;
1802 bool UnorderedAtomic;
1803 AAMDNodes AATags;
1804 ICFLoopSafetyInfo &SafetyInfo;
1805
1806 Value *maybeInsertLCSSAPHI(Value *V, BasicBlock *BB) const {
1807 if (Instruction *I = dyn_cast<Instruction>(V))
1808 if (Loop *L = LI.getLoopFor(I->getParent()))
1809 if (!L->contains(BB)) {
1810 // We need to create an LCSSA PHI node for the incoming value and
1811 // store that.
1812 PHINode *PN = PHINode::Create(I->getType(), PredCache.size(BB),
1813 I->getName() + ".lcssa", &BB->front());
1814 for (BasicBlock *Pred : PredCache.get(BB))
1815 PN->addIncoming(I, Pred);
1816 return PN;
1817 }
1818 return V;
1819 }
1820
1821public:
1822 LoopPromoter(Value *SP, ArrayRef<const Instruction *> Insts, SSAUpdater &S,
1823 const SmallSetVector<Value *, 8> &PMA,
1824 SmallVectorImpl<BasicBlock *> &LEB,
1825 SmallVectorImpl<Instruction *> &LIP,
1826 SmallVectorImpl<MemoryAccess *> &MSSAIP, PredIteratorCache &PIC,
1827 AliasSetTracker &ast, MemorySSAUpdater *MSSAU, LoopInfo &li,
1828 DebugLoc dl, int alignment, bool UnorderedAtomic,
1829 const AAMDNodes &AATags, ICFLoopSafetyInfo &SafetyInfo)
1830 : LoadAndStorePromoter(Insts, S), SomePtr(SP), PointerMustAliases(PMA),
1831 LoopExitBlocks(LEB), LoopInsertPts(LIP), MSSAInsertPts(MSSAIP),
1832 PredCache(PIC), AST(ast), MSSAU(MSSAU), LI(li), DL(std::move(dl)),
1833 Alignment(alignment), UnorderedAtomic(UnorderedAtomic), AATags(AATags),
1834 SafetyInfo(SafetyInfo) {}
1835
1836 bool isInstInList(Instruction *I,
1837 const SmallVectorImpl<Instruction *> &) const override {
1838 Value *Ptr;
1839 if (LoadInst *LI = dyn_cast<LoadInst>(I))
1840 Ptr = LI->getOperand(0);
1841 else
1842 Ptr = cast<StoreInst>(I)->getPointerOperand();
1843 return PointerMustAliases.count(Ptr);
1844 }
1845
1846 void doExtraRewritesBeforeFinalDeletion() override {
1847 // Insert stores after in the loop exit blocks. Each exit block gets a
1848 // store of the live-out values that feed them. Since we've already told
1849 // the SSA updater about the defs in the loop and the preheader
1850 // definition, it is all set and we can start using it.
1851 for (unsigned i = 0, e = LoopExitBlocks.size(); i != e; ++i) {
1852 BasicBlock *ExitBlock = LoopExitBlocks[i];
1853 Value *LiveInValue = SSA.GetValueInMiddleOfBlock(ExitBlock);
1854 LiveInValue = maybeInsertLCSSAPHI(LiveInValue, ExitBlock);
1855 Value *Ptr = maybeInsertLCSSAPHI(SomePtr, ExitBlock);
1856 Instruction *InsertPos = LoopInsertPts[i];
1857 StoreInst *NewSI = new StoreInst(LiveInValue, Ptr, InsertPos);
1858 if (UnorderedAtomic)
1859 NewSI->setOrdering(AtomicOrdering::Unordered);
1860 NewSI->setAlignment(MaybeAlign(Alignment));
1861 NewSI->setDebugLoc(DL);
1862 if (AATags)
1863 NewSI->setAAMetadata(AATags);
1864
1865 if (MSSAU) {
1866 MemoryAccess *MSSAInsertPoint = MSSAInsertPts[i];
1867 MemoryAccess *NewMemAcc;
1868 if (!MSSAInsertPoint) {
1869 NewMemAcc = MSSAU->createMemoryAccessInBB(
1870 NewSI, nullptr, NewSI->getParent(), MemorySSA::Beginning);
1871 } else {
1872 NewMemAcc =
1873 MSSAU->createMemoryAccessAfter(NewSI, nullptr, MSSAInsertPoint);
1874 }
1875 MSSAInsertPts[i] = NewMemAcc;
1876 MSSAU->insertDef(cast<MemoryDef>(NewMemAcc), true);
1877 // FIXME: true for safety, false may still be correct.
1878 }
1879 }
1880 }
1881
1882 void replaceLoadWithValue(LoadInst *LI, Value *V) const override {
1883 // Update alias analysis.
1884 AST.copyValue(LI, V);
1885 }
1886 void instructionDeleted(Instruction *I) const override {
1887 SafetyInfo.removeInstruction(I);
1888 AST.deleteValue(I);
1889 if (MSSAU)
1890 MSSAU->removeMemoryAccess(I);
1891 }
1892};
1893
1894
1895/// Return true iff we can prove that a caller of this function can not inspect
1896/// the contents of the provided object in a well defined program.
1897bool isKnownNonEscaping(Value *Object, const TargetLibraryInfo *TLI) {
1898 if (isa<AllocaInst>(Object))
1899 // Since the alloca goes out of scope, we know the caller can't retain a
1900 // reference to it and be well defined. Thus, we don't need to check for
1901 // capture.
1902 return true;
1903
1904 // For all other objects we need to know that the caller can't possibly
1905 // have gotten a reference to the object. There are two components of
1906 // that:
1907 // 1) Object can't be escaped by this function. This is what
1908 // PointerMayBeCaptured checks.
1909 // 2) Object can't have been captured at definition site. For this, we
1910 // need to know the return value is noalias. At the moment, we use a
1911 // weaker condition and handle only AllocLikeFunctions (which are
1912 // known to be noalias). TODO
1913 return isAllocLikeFn(Object, TLI) &&
1914 !PointerMayBeCaptured(Object, true, true);
1915}
1916
1917} // namespace
1918
1919/// Try to promote memory values to scalars by sinking stores out of the
1920/// loop and moving loads to before the loop. We do this by looping over
1921/// the stores in the loop, looking for stores to Must pointers which are
1922/// loop invariant.
1923///
1924bool llvm::promoteLoopAccessesToScalars(
1925 const SmallSetVector<Value *, 8> &PointerMustAliases,
1926 SmallVectorImpl<BasicBlock *> &ExitBlocks,
1927 SmallVectorImpl<Instruction *> &InsertPts,
1928 SmallVectorImpl<MemoryAccess *> &MSSAInsertPts, PredIteratorCache &PIC,
1929 LoopInfo *LI, DominatorTree *DT, const TargetLibraryInfo *TLI,
1930 Loop *CurLoop, AliasSetTracker *CurAST, MemorySSAUpdater *MSSAU,
1931 ICFLoopSafetyInfo *SafetyInfo, OptimizationRemarkEmitter *ORE) {
1932 // Verify inputs.
1933 assert(LI != nullptr && DT != nullptr && CurLoop != nullptr &&((LI != nullptr && DT != nullptr && CurLoop !=
nullptr && CurAST != nullptr && SafetyInfo !=
nullptr && "Unexpected Input to promoteLoopAccessesToScalars"
) ? static_cast<void> (0) : __assert_fail ("LI != nullptr && DT != nullptr && CurLoop != nullptr && CurAST != nullptr && SafetyInfo != nullptr && \"Unexpected Input to promoteLoopAccessesToScalars\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1935, __PRETTY_FUNCTION__))
1934 CurAST != nullptr && SafetyInfo != nullptr &&((LI != nullptr && DT != nullptr && CurLoop !=
nullptr && CurAST != nullptr && SafetyInfo !=
nullptr && "Unexpected Input to promoteLoopAccessesToScalars"
) ? static_cast<void> (0) : __assert_fail ("LI != nullptr && DT != nullptr && CurLoop != nullptr && CurAST != nullptr && SafetyInfo != nullptr && \"Unexpected Input to promoteLoopAccessesToScalars\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1935, __PRETTY_FUNCTION__))
1935 "Unexpected Input to promoteLoopAccessesToScalars")((LI != nullptr && DT != nullptr && CurLoop !=
nullptr && CurAST != nullptr && SafetyInfo !=
nullptr && "Unexpected Input to promoteLoopAccessesToScalars"
) ? static_cast<void> (0) : __assert_fail ("LI != nullptr && DT != nullptr && CurLoop != nullptr && CurAST != nullptr && SafetyInfo != nullptr && \"Unexpected Input to promoteLoopAccessesToScalars\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 1935, __PRETTY_FUNCTION__))
;
1936
1937 Value *SomePtr = *PointerMustAliases.begin();
1938 BasicBlock *Preheader = CurLoop->getLoopPreheader();
1939
1940 // It is not safe to promote a load/store from the loop if the load/store is
1941 // conditional. For example, turning:
1942 //
1943 // for () { if (c) *P += 1; }
1944 //
1945 // into:
1946 //
1947 // tmp = *P; for () { if (c) tmp +=1; } *P = tmp;
1948 //
1949 // is not safe, because *P may only be valid to access if 'c' is true.
1950 //
1951 // The safety property divides into two parts:
1952 // p1) The memory may not be dereferenceable on entry to the loop. In this
1953 // case, we can't insert the required load in the preheader.
1954 // p2) The memory model does not allow us to insert a store along any dynamic
1955 // path which did not originally have one.
1956 //
1957 // If at least one store is guaranteed to execute, both properties are
1958 // satisfied, and promotion is legal.
1959 //
1960 // This, however, is not a necessary condition. Even if no store/load is
1961 // guaranteed to execute, we can still establish these properties.
1962 // We can establish (p1) by proving that hoisting the load into the preheader
1963 // is safe (i.e. proving dereferenceability on all paths through the loop). We
1964 // can use any access within the alias set to prove dereferenceability,
1965 // since they're all must alias.
1966 //
1967 // There are two ways establish (p2):
1968 // a) Prove the location is thread-local. In this case the memory model
1969 // requirement does not apply, and stores are safe to insert.
1970 // b) Prove a store dominates every exit block. In this case, if an exit
1971 // blocks is reached, the original dynamic path would have taken us through
1972 // the store, so inserting a store into the exit block is safe. Note that this
1973 // is different from the store being guaranteed to execute. For instance,
1974 // if an exception is thrown on the first iteration of the loop, the original
1975 // store is never executed, but the exit blocks are not executed either.
1976
1977 bool DereferenceableInPH = false;
1978 bool SafeToInsertStore = false;
1979
1980 SmallVector<Instruction *, 64> LoopUses;
1981
1982 // We start with an alignment of one and try to find instructions that allow
1983 // us to prove better alignment.
1984 unsigned Alignment = 1;
1985 // Keep track of which types of access we see
1986 bool SawUnorderedAtomic = false;
1987 bool SawNotAtomic = false;
1988 AAMDNodes AATags;
1989
1990 const DataLayout &MDL = Preheader->getModule()->getDataLayout();
1991
1992 bool IsKnownThreadLocalObject = false;
1993 if (SafetyInfo->anyBlockMayThrow()) {
1994 // If a loop can throw, we have to insert a store along each unwind edge.
1995 // That said, we can't actually make the unwind edge explicit. Therefore,
1996 // we have to prove that the store is dead along the unwind edge. We do
1997 // this by proving that the caller can't have a reference to the object
1998 // after return and thus can't possibly load from the object.
1999 Value *Object = GetUnderlyingObject(SomePtr, MDL);
2000 if (!isKnownNonEscaping(Object, TLI))
2001 return false;
2002 // Subtlety: Alloca's aren't visible to callers, but *are* potentially
2003 // visible to other threads if captured and used during their lifetimes.
2004 IsKnownThreadLocalObject = !isa<AllocaInst>(Object);
2005 }
2006
2007 // Check that all of the pointers in the alias set have the same type. We
2008 // cannot (yet) promote a memory location that is loaded and stored in
2009 // different sizes. While we are at it, collect alignment and AA info.
2010 for (Value *ASIV : PointerMustAliases) {
2011 // Check that all of the pointers in the alias set have the same type. We
2012 // cannot (yet) promote a memory location that is loaded and stored in
2013 // different sizes.
2014 if (SomePtr->getType() != ASIV->getType())
2015 return false;
2016
2017 for (User *U : ASIV->users()) {
2018 // Ignore instructions that are outside the loop.
2019 Instruction *UI = dyn_cast<Instruction>(U);
2020 if (!UI || !CurLoop->contains(UI))
2021 continue;
2022
2023 // If there is an non-load/store instruction in the loop, we can't promote
2024 // it.
2025 if (LoadInst *Load = dyn_cast<LoadInst>(UI)) {
2026 if (!Load->isUnordered())
2027 return false;
2028
2029 SawUnorderedAtomic |= Load->isAtomic();
2030 SawNotAtomic |= !Load->isAtomic();
2031
2032 unsigned InstAlignment = Load->getAlignment();
2033 if (!InstAlignment)
2034 InstAlignment =
2035 MDL.getABITypeAlignment(Load->getType());
2036
2037 // Note that proving a load safe to speculate requires proving
2038 // sufficient alignment at the target location. Proving it guaranteed
2039 // to execute does as well. Thus we can increase our guaranteed
2040 // alignment as well.
2041 if (!DereferenceableInPH || (InstAlignment > Alignment))
2042 if (isSafeToExecuteUnconditionally(*Load, DT, CurLoop, SafetyInfo,
2043 ORE, Preheader->getTerminator())) {
2044 DereferenceableInPH = true;
2045 Alignment = std::max(Alignment, InstAlignment);
2046 }
2047 } else if (const StoreInst *Store = dyn_cast<StoreInst>(UI)) {
2048 // Stores *of* the pointer are not interesting, only stores *to* the
2049 // pointer.
2050 if (UI->getOperand(1) != ASIV)
2051 continue;
2052 if (!Store->isUnordered())
2053 return false;
2054
2055 SawUnorderedAtomic |= Store->isAtomic();
2056 SawNotAtomic |= !Store->isAtomic();
2057
2058 // If the store is guaranteed to execute, both properties are satisfied.
2059 // We may want to check if a store is guaranteed to execute even if we
2060 // already know that promotion is safe, since it may have higher
2061 // alignment than any other guaranteed stores, in which case we can
2062 // raise the alignment on the promoted store.
2063 unsigned InstAlignment = Store->getAlignment();
2064 if (!InstAlignment)
2065 InstAlignment =
2066 MDL.getABITypeAlignment(Store->getValueOperand()->getType());
2067
2068 if (!DereferenceableInPH || !SafeToInsertStore ||
2069 (InstAlignment > Alignment)) {
2070 if (SafetyInfo->isGuaranteedToExecute(*UI, DT, CurLoop)) {
2071 DereferenceableInPH = true;
2072 SafeToInsertStore = true;
2073 Alignment = std::max(Alignment, InstAlignment);
2074 }
2075 }
2076
2077 // If a store dominates all exit blocks, it is safe to sink.
2078 // As explained above, if an exit block was executed, a dominating
2079 // store must have been executed at least once, so we are not
2080 // introducing stores on paths that did not have them.
2081 // Note that this only looks at explicit exit blocks. If we ever
2082 // start sinking stores into unwind edges (see above), this will break.
2083 if (!SafeToInsertStore)
2084 SafeToInsertStore = llvm::all_of(ExitBlocks, [&](BasicBlock *Exit) {
2085 return DT->dominates(Store->getParent(), Exit);
2086 });
2087
2088 // If the store is not guaranteed to execute, we may still get
2089 // deref info through it.
2090 if (!DereferenceableInPH) {
2091 DereferenceableInPH = isDereferenceableAndAlignedPointer(
2092 Store->getPointerOperand(), Store->getValueOperand()->getType(),
2093 MaybeAlign(Store->getAlignment()), MDL,
2094 Preheader->getTerminator(), DT);
2095 }
2096 } else
2097 return false; // Not a load or store.
2098
2099 // Merge the AA tags.
2100 if (LoopUses.empty()) {
2101 // On the first load/store, just take its AA tags.
2102 UI->getAAMetadata(AATags);
2103 } else if (AATags) {
2104 UI->getAAMetadata(AATags, /* Merge = */ true);
2105 }
2106
2107 LoopUses.push_back(UI);
2108 }
2109 }
2110
2111 // If we found both an unordered atomic instruction and a non-atomic memory
2112 // access, bail. We can't blindly promote non-atomic to atomic since we
2113 // might not be able to lower the result. We can't downgrade since that
2114 // would violate memory model. Also, align 0 is an error for atomics.
2115 if (SawUnorderedAtomic && SawNotAtomic)
2116 return false;
2117
2118 // If we're inserting an atomic load in the preheader, we must be able to
2119 // lower it. We're only guaranteed to be able to lower naturally aligned
2120 // atomics.
2121 auto *SomePtrElemType = SomePtr->getType()->getPointerElementType();
2122 if (SawUnorderedAtomic &&
2123 Alignment < MDL.getTypeStoreSize(SomePtrElemType))
2124 return false;
2125
2126 // If we couldn't prove we can hoist the load, bail.
2127 if (!DereferenceableInPH)
2128 return false;
2129
2130 // We know we can hoist the load, but don't have a guaranteed store.
2131 // Check whether the location is thread-local. If it is, then we can insert
2132 // stores along paths which originally didn't have them without violating the
2133 // memory model.
2134 if (!SafeToInsertStore) {
2135 if (IsKnownThreadLocalObject)
2136 SafeToInsertStore = true;
2137 else {
2138 Value *Object = GetUnderlyingObject(SomePtr, MDL);
2139 SafeToInsertStore =
2140 (isAllocLikeFn(Object, TLI) || isa<AllocaInst>(Object)) &&
2141 !PointerMayBeCaptured(Object, true, true);
2142 }
2143 }
2144
2145 // If we've still failed to prove we can sink the store, give up.
2146 if (!SafeToInsertStore)
2147 return false;
2148
2149 // Otherwise, this is safe to promote, lets do it!
2150 LLVM_DEBUG(dbgs() << "LICM: Promoting value stored to in loop: " << *SomePtrdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM: Promoting value stored to in loop: "
<< *SomePtr << '\n'; } } while (false)
2151 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "LICM: Promoting value stored to in loop: "
<< *SomePtr << '\n'; } } while (false)
;
2152 ORE->emit([&]() {
2153 return OptimizationRemark(DEBUG_TYPE"licm", "PromoteLoopAccessesToScalar",
2154 LoopUses[0])
2155 << "Moving accesses to memory location out of the loop";
2156 });
2157 ++NumPromoted;
2158
2159 // Grab a debug location for the inserted loads/stores; given that the
2160 // inserted loads/stores have little relation to the original loads/stores,
2161 // this code just arbitrarily picks a location from one, since any debug
2162 // location is better than none.
2163 DebugLoc DL = LoopUses[0]->getDebugLoc();
2164
2165 // We use the SSAUpdater interface to insert phi nodes as required.
2166 SmallVector<PHINode *, 16> NewPHIs;
2167 SSAUpdater SSA(&NewPHIs);
2168 LoopPromoter Promoter(SomePtr, LoopUses, SSA, PointerMustAliases, ExitBlocks,
2169 InsertPts, MSSAInsertPts, PIC, *CurAST, MSSAU, *LI, DL,
2170 Alignment, SawUnorderedAtomic, AATags, *SafetyInfo);
2171
2172 // Set up the preheader to have a definition of the value. It is the live-out
2173 // value from the preheader that uses in the loop will use.
2174 LoadInst *PreheaderLoad = new LoadInst(
2175 SomePtr->getType()->getPointerElementType(), SomePtr,
2176 SomePtr->getName() + ".promoted", Preheader->getTerminator());
2177 if (SawUnorderedAtomic)
2178 PreheaderLoad->setOrdering(AtomicOrdering::Unordered);
2179 PreheaderLoad->setAlignment(MaybeAlign(Alignment));
2180 PreheaderLoad->setDebugLoc(DL);
2181 if (AATags)
2182 PreheaderLoad->setAAMetadata(AATags);
2183 SSA.AddAvailableValue(Preheader, PreheaderLoad);
2184
2185 if (MSSAU) {
2186 MemoryAccess *PreheaderLoadMemoryAccess = MSSAU->createMemoryAccessInBB(
2187 PreheaderLoad, nullptr, PreheaderLoad->getParent(), MemorySSA::End);
2188 MemoryUse *NewMemUse = cast<MemoryUse>(PreheaderLoadMemoryAccess);
2189 MSSAU->insertUse(NewMemUse, /*RenameUses=*/true);
2190 }
2191
2192 if (MSSAU && VerifyMemorySSA)
2193 MSSAU->getMemorySSA()->verifyMemorySSA();
2194 // Rewrite all the loads in the loop and remember all the definitions from
2195 // stores in the loop.
2196 Promoter.run(LoopUses);
2197
2198 if (MSSAU && VerifyMemorySSA)
2199 MSSAU->getMemorySSA()->verifyMemorySSA();
2200 // If the SSAUpdater didn't use the load in the preheader, just zap it now.
2201 if (PreheaderLoad->use_empty())
2202 eraseInstruction(*PreheaderLoad, *SafetyInfo, CurAST, MSSAU);
2203
2204 return true;
2205}
2206
2207/// Returns an owning pointer to an alias set which incorporates aliasing info
2208/// from L and all subloops of L.
2209/// FIXME: In new pass manager, there is no helper function to handle loop
2210/// analysis such as cloneBasicBlockAnalysis, so the AST needs to be recomputed
2211/// from scratch for every loop. Hook up with the helper functions when
2212/// available in the new pass manager to avoid redundant computation.
2213std::unique_ptr<AliasSetTracker>
2214LoopInvariantCodeMotion::collectAliasInfoForLoop(Loop *L, LoopInfo *LI,
2215 AliasAnalysis *AA) {
2216 std::unique_ptr<AliasSetTracker> CurAST;
2217 SmallVector<Loop *, 4> RecomputeLoops;
2218 for (Loop *InnerL : L->getSubLoops()) {
2219 auto MapI = LoopToAliasSetMap.find(InnerL);
2220 // If the AST for this inner loop is missing it may have been merged into
2221 // some other loop's AST and then that loop unrolled, and so we need to
2222 // recompute it.
2223 if (MapI == LoopToAliasSetMap.end()) {
2224 RecomputeLoops.push_back(InnerL);
2225 continue;
2226 }
2227 std::unique_ptr<AliasSetTracker> InnerAST = std::move(MapI->second);
2228
2229 if (CurAST) {
2230 // What if InnerLoop was modified by other passes ?
2231 // Once we've incorporated the inner loop's AST into ours, we don't need
2232 // the subloop's anymore.
2233 CurAST->add(*InnerAST);
2234 } else {
2235 CurAST = std::move(InnerAST);
2236 }
2237 LoopToAliasSetMap.erase(MapI);
2238 }
2239 if (!CurAST)
2240 CurAST = std::make_unique<AliasSetTracker>(*AA);
2241
2242 // Add everything from the sub loops that are no longer directly available.
2243 for (Loop *InnerL : RecomputeLoops)
2244 for (BasicBlock *BB : InnerL->blocks())
2245 CurAST->add(*BB);
2246
2247 // And merge in this loop (without anything from inner loops).
2248 for (BasicBlock *BB : L->blocks())
2249 if (LI->getLoopFor(BB) == L)
2250 CurAST->add(*BB);
2251
2252 return CurAST;
2253}
2254
2255std::unique_ptr<AliasSetTracker>
2256LoopInvariantCodeMotion::collectAliasInfoForLoopWithMSSA(
2257 Loop *L, AliasAnalysis *AA, MemorySSAUpdater *MSSAU) {
2258 auto *MSSA = MSSAU->getMemorySSA();
2259 auto CurAST = std::make_unique<AliasSetTracker>(*AA, MSSA, L);
2260 CurAST->addAllInstructionsInLoopUsingMSSA();
2261 return CurAST;
2262}
2263
2264/// Simple analysis hook. Clone alias set info.
2265///
2266void LegacyLICMPass::cloneBasicBlockAnalysis(BasicBlock *From, BasicBlock *To,
2267 Loop *L) {
2268 auto ASTIt = LICM.getLoopToAliasSetMap().find(L);
2269 if (ASTIt == LICM.getLoopToAliasSetMap().end())
2270 return;
2271
2272 ASTIt->second->copyValue(From, To);
2273}
2274
2275/// Simple Analysis hook. Delete value V from alias set
2276///
2277void LegacyLICMPass::deleteAnalysisValue(Value *V, Loop *L) {
2278 auto ASTIt = LICM.getLoopToAliasSetMap().find(L);
2279 if (ASTIt == LICM.getLoopToAliasSetMap().end())
2280 return;
2281
2282 ASTIt->second->deleteValue(V);
2283}
2284
2285/// Simple Analysis hook. Delete value L from alias set map.
2286///
2287void LegacyLICMPass::deleteAnalysisLoop(Loop *L) {
2288 if (!LICM.getLoopToAliasSetMap().count(L))
2289 return;
2290
2291 LICM.getLoopToAliasSetMap().erase(L);
2292}
2293
2294static bool pointerInvalidatedByLoop(MemoryLocation MemLoc,
2295 AliasSetTracker *CurAST, Loop *CurLoop,
2296 AliasAnalysis *AA) {
2297 // First check to see if any of the basic blocks in CurLoop invalidate *V.
2298 bool isInvalidatedAccordingToAST = CurAST->getAliasSetFor(MemLoc).isMod();
2299
2300 if (!isInvalidatedAccordingToAST || !LICMN2Theshold)
2301 return isInvalidatedAccordingToAST;
2302
2303 // Check with a diagnostic analysis if we can refine the information above.
2304 // This is to identify the limitations of using the AST.
2305 // The alias set mechanism used by LICM has a major weakness in that it
2306 // combines all things which may alias into a single set *before* asking
2307 // modref questions. As a result, a single readonly call within a loop will
2308 // collapse all loads and stores into a single alias set and report
2309 // invalidation if the loop contains any store. For example, readonly calls
2310 // with deopt states have this form and create a general alias set with all
2311 // loads and stores. In order to get any LICM in loops containing possible
2312 // deopt states we need a more precise invalidation of checking the mod ref
2313 // info of each instruction within the loop and LI. This has a complexity of
2314 // O(N^2), so currently, it is used only as a diagnostic tool since the
2315 // default value of LICMN2Threshold is zero.
2316
2317 // Don't look at nested loops.
2318 if (CurLoop->begin() != CurLoop->end())
2319 return true;
2320
2321 int N = 0;
2322 for (BasicBlock *BB : CurLoop->getBlocks())
2323 for (Instruction &I : *BB) {
2324 if (N >= LICMN2Theshold) {
2325 LLVM_DEBUG(dbgs() << "Alasing N2 threshold exhausted for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "Alasing N2 threshold exhausted for "
<< *(MemLoc.Ptr) << "\n"; } } while (false)
2326 << *(MemLoc.Ptr) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "Alasing N2 threshold exhausted for "
<< *(MemLoc.Ptr) << "\n"; } } while (false)
;
2327 return true;
2328 }
2329 N++;
2330 auto Res = AA->getModRefInfo(&I, MemLoc);
2331 if (isModSet(Res)) {
2332 LLVM_DEBUG(dbgs() << "Aliasing failed on " << I << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "Aliasing failed on " << I <<
" for " << *(MemLoc.Ptr) << "\n"; } } while (false
)
2333 << *(MemLoc.Ptr) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "Aliasing failed on " << I <<
" for " << *(MemLoc.Ptr) << "\n"; } } while (false
)
;
2334 return true;
2335 }
2336 }
2337 LLVM_DEBUG(dbgs() << "Aliasing okay for " << *(MemLoc.Ptr) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("licm")) { dbgs() << "Aliasing okay for " << *(MemLoc
.Ptr) << "\n"; } } while (false)
;
2338 return false;
2339}
2340
2341static bool pointerInvalidatedByLoopWithMSSA(MemorySSA *MSSA, MemoryUse *MU,
2342 Loop *CurLoop,
2343 SinkAndHoistLICMFlags &Flags) {
2344 // For hoisting, use the walker to determine safety
2345 if (!Flags.IsSink) {
2346 MemoryAccess *Source;
2347 // See declaration of SetLicmMssaOptCap for usage details.
2348 if (Flags.LicmMssaOptCounter >= Flags.LicmMssaOptCap)
2349 Source = MU->getDefiningAccess();
2350 else {
2351 Source = MSSA->getSkipSelfWalker()->getClobberingMemoryAccess(MU);
2352 Flags.LicmMssaOptCounter++;
2353 }
2354 return !MSSA->isLiveOnEntryDef(Source) &&
2355 CurLoop->contains(Source->getBlock());
2356 }
2357
2358 // For sinking, we'd need to check all Defs below this use. The getClobbering
2359 // call will look on the backedge of the loop, but will check aliasing with
2360 // the instructions on the previous iteration.
2361 // For example:
2362 // for (i ... )
2363 // load a[i] ( Use (LoE)
2364 // store a[i] ( 1 = Def (2), with 2 = Phi for the loop.
2365 // i++;
2366 // The load sees no clobbering inside the loop, as the backedge alias check
2367 // does phi translation, and will check aliasing against store a[i-1].
2368 // However sinking the load outside the loop, below the store is incorrect.
2369
2370 // For now, only sink if there are no Defs in the loop, and the existing ones
2371 // precede the use and are in the same block.
2372 // FIXME: Increase precision: Safe to sink if Use post dominates the Def;
2373 // needs PostDominatorTreeAnalysis.
2374 // FIXME: More precise: no Defs that alias this Use.
2375 if (Flags.NoOfMemAccTooLarge)
2376 return true;
2377 for (auto *BB : CurLoop->getBlocks())
2378 if (auto *Accesses = MSSA->getBlockDefs(BB))
2379 for (const auto &MA : *Accesses)
2380 if (const auto *MD = dyn_cast<MemoryDef>(&MA))
2381 if (MU->getBlock() != MD->getBlock() ||
2382 !MSSA->locallyDominates(MD, MU))
2383 return true;
2384 return false;
2385}
2386
2387/// Little predicate that returns true if the specified basic block is in
2388/// a subloop of the current one, not the current one itself.
2389///
2390static bool inSubLoop(BasicBlock *BB, Loop *CurLoop, LoopInfo *LI) {
2391 assert(CurLoop->contains(BB) && "Only valid if BB is IN the loop")((CurLoop->contains(BB) && "Only valid if BB is IN the loop"
) ? static_cast<void> (0) : __assert_fail ("CurLoop->contains(BB) && \"Only valid if BB is IN the loop\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/Transforms/Scalar/LICM.cpp"
, 2391, __PRETTY_FUNCTION__))
;
2392 return LI->getLoopFor(BB) != CurLoop;
2393}

/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/include/llvm/IR/PatternMatch.h

1//===- PatternMatch.h - Match on the LLVM IR --------------------*- 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 provides a simple and efficient mechanism for performing general
10// tree-based pattern matches on the LLVM IR. The power of these routines is
11// that it allows you to write concise patterns that are expressive and easy to
12// understand. The other major advantage of this is that it allows you to
13// trivially capture/bind elements in the pattern to variables. For example,
14// you can do something like this:
15//
16// Value *Exp = ...
17// Value *X, *Y; ConstantInt *C1, *C2; // (X & C1) | (Y & C2)
18// if (match(Exp, m_Or(m_And(m_Value(X), m_ConstantInt(C1)),
19// m_And(m_Value(Y), m_ConstantInt(C2))))) {
20// ... Pattern is matched and variables are bound ...
21// }
22//
23// This is primarily useful to things like the instruction combiner, but can
24// also be useful for static analysis tools or code generators.
25//
26//===----------------------------------------------------------------------===//
27
28#ifndef LLVM_IR_PATTERNMATCH_H
29#define LLVM_IR_PATTERNMATCH_H
30
31#include "llvm/ADT/APFloat.h"
32#include "llvm/ADT/APInt.h"
33#include "llvm/IR/Constant.h"
34#include "llvm/IR/Constants.h"
35#include "llvm/IR/InstrTypes.h"
36#include "llvm/IR/Instruction.h"
37#include "llvm/IR/Instructions.h"
38#include "llvm/IR/IntrinsicInst.h"
39#include "llvm/IR/Intrinsics.h"
40#include "llvm/IR/Operator.h"
41#include "llvm/IR/Value.h"
42#include "llvm/Support/Casting.h"
43#include <cstdint>
44
45namespace llvm {
46namespace PatternMatch {
47
48template <typename Val, typename Pattern> bool match(Val *V, const Pattern &P) {
49 return const_cast<Pattern &>(P).match(V);
33
Calling 'IntrinsicID_match::match'
37
Returning from 'IntrinsicID_match::match'
38
Returning zero, which participates in a condition later
42
Calling 'IntrinsicID_match::match'
46
Returning from 'IntrinsicID_match::match'
47
Returning zero, which participates in a condition later
50}
51
52template <typename SubPattern_t> struct OneUse_match {
53 SubPattern_t SubPattern;
54
55 OneUse_match(const SubPattern_t &SP) : SubPattern(SP) {}
56
57 template <typename OpTy> bool match(OpTy *V) {
58 return V->hasOneUse() && SubPattern.match(V);
59 }
60};
61
62template <typename T> inline OneUse_match<T> m_OneUse(const T &SubPattern) {
63 return SubPattern;
64}
65
66template <typename Class> struct class_match {
67 template <typename ITy> bool match(ITy *V) { return isa<Class>(V); }
68};
69
70/// Match an arbitrary value and ignore it.
71inline class_match<Value> m_Value() { return class_match<Value>(); }
72
73/// Match an arbitrary binary operation and ignore it.
74inline class_match<BinaryOperator> m_BinOp() {
75 return class_match<BinaryOperator>();
76}
77
78/// Matches any compare instruction and ignore it.
79inline class_match<CmpInst> m_Cmp() { return class_match<CmpInst>(); }
80
81/// Match an arbitrary ConstantInt and ignore it.
82inline class_match<ConstantInt> m_ConstantInt() {
83 return class_match<ConstantInt>();
84}
85
86/// Match an arbitrary undef constant.
87inline class_match<UndefValue> m_Undef() { return class_match<UndefValue>(); }
88
89/// Match an arbitrary Constant and ignore it.
90inline class_match<Constant> m_Constant() { return class_match<Constant>(); }
91
92/// Match an arbitrary basic block value and ignore it.
93inline class_match<BasicBlock> m_BasicBlock() {
94 return class_match<BasicBlock>();
95}
96
97/// Inverting matcher
98template <typename Ty> struct match_unless {
99 Ty M;
100
101 match_unless(const Ty &Matcher) : M(Matcher) {}
102
103 template <typename ITy> bool match(ITy *V) { return !M.match(V); }
104};
105
106/// Match if the inner matcher does *NOT* match.
107template <typename Ty> inline match_unless<Ty> m_Unless(const Ty &M) {
108 return match_unless<Ty>(M);
109}
110
111/// Matching combinators
112template <typename LTy, typename RTy> struct match_combine_or {
113 LTy L;
114 RTy R;
115
116 match_combine_or(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
117
118 template <typename ITy> bool match(ITy *V) {
119 if (L.match(V))
120 return true;
121 if (R.match(V))
122 return true;
123 return false;
124 }
125};
126
127template <typename LTy, typename RTy> struct match_combine_and {
128 LTy L;
129 RTy R;
130
131 match_combine_and(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
132
133 template <typename ITy> bool match(ITy *V) {
134 if (L.match(V))
135 if (R.match(V))
136 return true;
137 return false;
138 }
139};
140
141/// Combine two pattern matchers matching L || R
142template <typename LTy, typename RTy>
143inline match_combine_or<LTy, RTy> m_CombineOr(const LTy &L, const RTy &R) {
144 return match_combine_or<LTy, RTy>(L, R);
145}
146
147/// Combine two pattern matchers matching L && R
148template <typename LTy, typename RTy>
149inline match_combine_and<LTy, RTy> m_CombineAnd(const LTy &L, const RTy &R) {
150 return match_combine_and<LTy, RTy>(L, R);
151}
152
153struct apint_match {
154 const APInt *&Res;
155
156 apint_match(const APInt *&R) : Res(R) {}
157
158 template <typename ITy> bool match(ITy *V) {
159 if (auto *CI = dyn_cast<ConstantInt>(V)) {
160 Res = &CI->getValue();
161 return true;
162 }
163 if (V->getType()->isVectorTy())
164 if (const auto *C = dyn_cast<Constant>(V))
165 if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue())) {
166 Res = &CI->getValue();
167 return true;
168 }
169 return false;
170 }
171};
172// Either constexpr if or renaming ConstantFP::getValueAPF to
173// ConstantFP::getValue is needed to do it via single template
174// function for both apint/apfloat.
175struct apfloat_match {
176 const APFloat *&Res;
177 apfloat_match(const APFloat *&R) : Res(R) {}
178 template <typename ITy> bool match(ITy *V) {
179 if (auto *CI = dyn_cast<ConstantFP>(V)) {
180 Res = &CI->getValueAPF();
181 return true;
182 }
183 if (V->getType()->isVectorTy())
184 if (const auto *C = dyn_cast<Constant>(V))
185 if (auto *CI = dyn_cast_or_null<ConstantFP>(C->getSplatValue())) {
186 Res = &CI->getValueAPF();
187 return true;
188 }
189 return false;
190 }
191};
192
193/// Match a ConstantInt or splatted ConstantVector, binding the
194/// specified pointer to the contained APInt.
195inline apint_match m_APInt(const APInt *&Res) { return Res; }
196
197/// Match a ConstantFP or splatted ConstantVector, binding the
198/// specified pointer to the contained APFloat.
199inline apfloat_match m_APFloat(const APFloat *&Res) { return Res; }
200
201template <int64_t Val> struct constantint_match {
202 template <typename ITy> bool match(ITy *V) {
203 if (const auto *CI = dyn_cast<ConstantInt>(V)) {
204 const APInt &CIV = CI->getValue();
205 if (Val >= 0)
206 return CIV == static_cast<uint64_t>(Val);
207 // If Val is negative, and CI is shorter than it, truncate to the right
208 // number of bits. If it is larger, then we have to sign extend. Just
209 // compare their negated values.
210 return -CIV == -Val;
211 }
212 return false;
213 }
214};
215
216/// Match a ConstantInt with a specific value.
217template <int64_t Val> inline constantint_match<Val> m_ConstantInt() {
218 return constantint_match<Val>();
219}
220
221/// This helper class is used to match scalar and vector integer constants that
222/// satisfy a specified predicate.
223/// For vector constants, undefined elements are ignored.
224template <typename Predicate> struct cst_pred_ty : public Predicate {
225 template <typename ITy> bool match(ITy *V) {
226 if (const auto *CI = dyn_cast<ConstantInt>(V))
227 return this->isValue(CI->getValue());
228 if (V->getType()->isVectorTy()) {
229 if (const auto *C = dyn_cast<Constant>(V)) {
230 if (const auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
231 return this->isValue(CI->getValue());
232
233 // Non-splat vector constant: check each element for a match.
234 unsigned NumElts = V->getType()->getVectorNumElements();
235 assert(NumElts != 0 && "Constant vector with no elements?")((NumElts != 0 && "Constant vector with no elements?"
) ? static_cast<void> (0) : __assert_fail ("NumElts != 0 && \"Constant vector with no elements?\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/include/llvm/IR/PatternMatch.h"
, 235, __PRETTY_FUNCTION__))
;
236 bool HasNonUndefElements = false;
237 for (unsigned i = 0; i != NumElts; ++i) {
238 Constant *Elt = C->getAggregateElement(i);
239 if (!Elt)
240 return false;
241 if (isa<UndefValue>(Elt))
242 continue;
243 auto *CI = dyn_cast<ConstantInt>(Elt);
244 if (!CI || !this->isValue(CI->getValue()))
245 return false;
246 HasNonUndefElements = true;
247 }
248 return HasNonUndefElements;
249 }
250 }
251 return false;
252 }
253};
254
255/// This helper class is used to match scalar and vector constants that
256/// satisfy a specified predicate, and bind them to an APInt.
257template <typename Predicate> struct api_pred_ty : public Predicate {
258 const APInt *&Res;
259
260 api_pred_ty(const APInt *&R) : Res(R) {}
261
262 template <typename ITy> bool match(ITy *V) {
263 if (const auto *CI = dyn_cast<ConstantInt>(V))
264 if (this->isValue(CI->getValue())) {
265 Res = &CI->getValue();
266 return true;
267 }
268 if (V->getType()->isVectorTy())
269 if (const auto *C = dyn_cast<Constant>(V))
270 if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
271 if (this->isValue(CI->getValue())) {
272 Res = &CI->getValue();
273 return true;
274 }
275
276 return false;
277 }
278};
279
280/// This helper class is used to match scalar and vector floating-point
281/// constants that satisfy a specified predicate.
282/// For vector constants, undefined elements are ignored.
283template <typename Predicate> struct cstfp_pred_ty : public Predicate {
284 template <typename ITy> bool match(ITy *V) {
285 if (const auto *CF = dyn_cast<ConstantFP>(V))
286 return this->isValue(CF->getValueAPF());
287 if (V->getType()->isVectorTy()) {
288 if (const auto *C = dyn_cast<Constant>(V)) {
289 if (const auto *CF = dyn_cast_or_null<ConstantFP>(C->getSplatValue()))
290 return this->isValue(CF->getValueAPF());
291
292 // Non-splat vector constant: check each element for a match.
293 unsigned NumElts = V->getType()->getVectorNumElements();
294 assert(NumElts != 0 && "Constant vector with no elements?")((NumElts != 0 && "Constant vector with no elements?"
) ? static_cast<void> (0) : __assert_fail ("NumElts != 0 && \"Constant vector with no elements?\""
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/include/llvm/IR/PatternMatch.h"
, 294, __PRETTY_FUNCTION__))
;
295 bool HasNonUndefElements = false;
296 for (unsigned i = 0; i != NumElts; ++i) {
297 Constant *Elt = C->getAggregateElement(i);
298 if (!Elt)
299 return false;
300 if (isa<UndefValue>(Elt))
301 continue;
302 auto *CF = dyn_cast<ConstantFP>(Elt);
303 if (!CF || !this->isValue(CF->getValueAPF()))
304 return false;
305 HasNonUndefElements = true;
306 }
307 return HasNonUndefElements;
308 }
309 }
310 return false;
311 }
312};
313
314///////////////////////////////////////////////////////////////////////////////
315//
316// Encapsulate constant value queries for use in templated predicate matchers.
317// This allows checking if constants match using compound predicates and works
318// with vector constants, possibly with relaxed constraints. For example, ignore
319// undef values.
320//
321///////////////////////////////////////////////////////////////////////////////
322
323struct is_any_apint {
324 bool isValue(const APInt &C) { return true; }
325};
326/// Match an integer or vector with any integral constant.
327/// For vectors, this includes constants with undefined elements.
328inline cst_pred_ty<is_any_apint> m_AnyIntegralConstant() {
329 return cst_pred_ty<is_any_apint>();
330}
331
332struct is_all_ones {
333 bool isValue(const APInt &C) { return C.isAllOnesValue(); }
334};
335/// Match an integer or vector with all bits set.
336/// For vectors, this includes constants with undefined elements.
337inline cst_pred_ty<is_all_ones> m_AllOnes() {
338 return cst_pred_ty<is_all_ones>();
339}
340
341struct is_maxsignedvalue {
342 bool isValue(const APInt &C) { return C.isMaxSignedValue(); }
343};
344/// Match an integer or vector with values having all bits except for the high
345/// bit set (0x7f...).
346/// For vectors, this includes constants with undefined elements.
347inline cst_pred_ty<is_maxsignedvalue> m_MaxSignedValue() {
348 return cst_pred_ty<is_maxsignedvalue>();
349}
350inline api_pred_ty<is_maxsignedvalue> m_MaxSignedValue(const APInt *&V) {
351 return V;
352}
353
354struct is_negative {
355 bool isValue(const APInt &C) { return C.isNegative(); }
356};
357/// Match an integer or vector of negative values.
358/// For vectors, this includes constants with undefined elements.
359inline cst_pred_ty<is_negative> m_Negative() {
360 return cst_pred_ty<is_negative>();
361}
362inline api_pred_ty<is_negative> m_Negative(const APInt *&V) {
363 return V;
364}
365
366struct is_nonnegative {
367 bool isValue(const APInt &C) { return C.isNonNegative(); }
368};
369/// Match an integer or vector of non-negative values.
370/// For vectors, this includes constants with undefined elements.
371inline cst_pred_ty<is_nonnegative> m_NonNegative() {
372 return cst_pred_ty<is_nonnegative>();
373}
374inline api_pred_ty<is_nonnegative> m_NonNegative(const APInt *&V) {
375 return V;
376}
377
378struct is_strictlypositive {
379 bool isValue(const APInt &C) { return C.isStrictlyPositive(); }
380};
381/// Match an integer or vector of strictly positive values.
382/// For vectors, this includes constants with undefined elements.
383inline cst_pred_ty<is_strictlypositive> m_StrictlyPositive() {
384 return cst_pred_ty<is_strictlypositive>();
385}
386inline api_pred_ty<is_strictlypositive> m_StrictlyPositive(const APInt *&V) {
387 return V;
388}
389
390struct is_nonpositive {
391 bool isValue(const APInt &C) { return C.isNonPositive(); }
392};
393/// Match an integer or vector of non-positive values.
394/// For vectors, this includes constants with undefined elements.
395inline cst_pred_ty<is_nonpositive> m_NonPositive() {
396 return cst_pred_ty<is_nonpositive>();
397}
398inline api_pred_ty<is_nonpositive> m_NonPositive(const APInt *&V) { return V; }
399
400struct is_one {
401 bool isValue(const APInt &C) { return C.isOneValue(); }
402};
403/// Match an integer 1 or a vector with all elements equal to 1.
404/// For vectors, this includes constants with undefined elements.
405inline cst_pred_ty<is_one> m_One() {
406 return cst_pred_ty<is_one>();
407}
408
409struct is_zero_int {
410 bool isValue(const APInt &C) { return C.isNullValue(); }
411};
412/// Match an integer 0 or a vector with all elements equal to 0.
413/// For vectors, this includes constants with undefined elements.
414inline cst_pred_ty<is_zero_int> m_ZeroInt() {
415 return cst_pred_ty<is_zero_int>();
416}
417
418struct is_zero {
419 template <typename ITy> bool match(ITy *V) {
420 auto *C = dyn_cast<Constant>(V);
421 return C && (C->isNullValue() || cst_pred_ty<is_zero_int>().match(C));
422 }
423};
424/// Match any null constant or a vector with all elements equal to 0.
425/// For vectors, this includes constants with undefined elements.
426inline is_zero m_Zero() {
427 return is_zero();
428}
429
430struct is_power2 {
431 bool isValue(const APInt &C) { return C.isPowerOf2(); }
432};
433/// Match an integer or vector power-of-2.
434/// For vectors, this includes constants with undefined elements.
435inline cst_pred_ty<is_power2> m_Power2() {
436 return cst_pred_ty<is_power2>();
437}
438inline api_pred_ty<is_power2> m_Power2(const APInt *&V) {
439 return V;
440}
441
442struct is_negated_power2 {
443 bool isValue(const APInt &C) { return (-C).isPowerOf2(); }
444};
445/// Match a integer or vector negated power-of-2.
446/// For vectors, this includes constants with undefined elements.
447inline cst_pred_ty<is_negated_power2> m_NegatedPower2() {
448 return cst_pred_ty<is_negated_power2>();
449}
450inline api_pred_ty<is_negated_power2> m_NegatedPower2(const APInt *&V) {
451 return V;
452}
453
454struct is_power2_or_zero {
455 bool isValue(const APInt &C) { return !C || C.isPowerOf2(); }
456};
457/// Match an integer or vector of 0 or power-of-2 values.
458/// For vectors, this includes constants with undefined elements.
459inline cst_pred_ty<is_power2_or_zero> m_Power2OrZero() {
460 return cst_pred_ty<is_power2_or_zero>();
461}
462inline api_pred_ty<is_power2_or_zero> m_Power2OrZero(const APInt *&V) {
463 return V;
464}
465
466struct is_sign_mask {
467 bool isValue(const APInt &C) { return C.isSignMask(); }
468};
469/// Match an integer or vector with only the sign bit(s) set.
470/// For vectors, this includes constants with undefined elements.
471inline cst_pred_ty<is_sign_mask> m_SignMask() {
472 return cst_pred_ty<is_sign_mask>();
473}
474
475struct is_lowbit_mask {
476 bool isValue(const APInt &C) { return C.isMask(); }
477};
478/// Match an integer or vector with only the low bit(s) set.
479/// For vectors, this includes constants with undefined elements.
480inline cst_pred_ty<is_lowbit_mask> m_LowBitMask() {
481 return cst_pred_ty<is_lowbit_mask>();
482}
483
484struct icmp_pred_with_threshold {
485 ICmpInst::Predicate Pred;
486 const APInt *Thr;
487 bool isValue(const APInt &C) {
488 switch (Pred) {
489 case ICmpInst::Predicate::ICMP_EQ:
490 return C.eq(*Thr);
491 case ICmpInst::Predicate::ICMP_NE:
492 return C.ne(*Thr);
493 case ICmpInst::Predicate::ICMP_UGT:
494 return C.ugt(*Thr);
495 case ICmpInst::Predicate::ICMP_UGE:
496 return C.uge(*Thr);
497 case ICmpInst::Predicate::ICMP_ULT:
498 return C.ult(*Thr);
499 case ICmpInst::Predicate::ICMP_ULE:
500 return C.ule(*Thr);
501 case ICmpInst::Predicate::ICMP_SGT:
502 return C.sgt(*Thr);
503 case ICmpInst::Predicate::ICMP_SGE:
504 return C.sge(*Thr);
505 case ICmpInst::Predicate::ICMP_SLT:
506 return C.slt(*Thr);
507 case ICmpInst::Predicate::ICMP_SLE:
508 return C.sle(*Thr);
509 default:
510 llvm_unreachable("Unhandled ICmp predicate")::llvm::llvm_unreachable_internal("Unhandled ICmp predicate",
"/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/include/llvm/IR/PatternMatch.h"
, 510)
;
511 }
512 }
513};
514/// Match an integer or vector with every element comparing 'pred' (eg/ne/...)
515/// to Threshold. For vectors, this includes constants with undefined elements.
516inline cst_pred_ty<icmp_pred_with_threshold>
517m_SpecificInt_ICMP(ICmpInst::Predicate Predicate, const APInt &Threshold) {
518 cst_pred_ty<icmp_pred_with_threshold> P;
519 P.Pred = Predicate;
520 P.Thr = &Threshold;
521 return P;
522}
523
524struct is_nan {
525 bool isValue(const APFloat &C) { return C.isNaN(); }
526};
527/// Match an arbitrary NaN constant. This includes quiet and signalling nans.
528/// For vectors, this includes constants with undefined elements.
529inline cstfp_pred_ty<is_nan> m_NaN() {
530 return cstfp_pred_ty<is_nan>();
531}
532
533struct is_any_zero_fp {
534 bool isValue(const APFloat &C) { return C.isZero(); }
535};
536/// Match a floating-point negative zero or positive zero.
537/// For vectors, this includes constants with undefined elements.
538inline cstfp_pred_ty<is_any_zero_fp> m_AnyZeroFP() {
539 return cstfp_pred_ty<is_any_zero_fp>();
540}
541
542struct is_pos_zero_fp {
543 bool isValue(const APFloat &C) { return C.isPosZero(); }
544};
545/// Match a floating-point positive zero.
546/// For vectors, this includes constants with undefined elements.
547inline cstfp_pred_ty<is_pos_zero_fp> m_PosZeroFP() {
548 return cstfp_pred_ty<is_pos_zero_fp>();
549}
550
551struct is_neg_zero_fp {
552 bool isValue(const APFloat &C) { return C.isNegZero(); }
553};
554/// Match a floating-point negative zero.
555/// For vectors, this includes constants with undefined elements.
556inline cstfp_pred_ty<is_neg_zero_fp> m_NegZeroFP() {
557 return cstfp_pred_ty<is_neg_zero_fp>();
558}
559
560///////////////////////////////////////////////////////////////////////////////
561
562template <typename Class> struct bind_ty {
563 Class *&VR;
564
565 bind_ty(Class *&V) : VR(V) {}
566
567 template <typename ITy> bool match(ITy *V) {
568 if (auto *CV = dyn_cast<Class>(V)) {
569 VR = CV;
570 return true;
571 }
572 return false;
573 }
574};
575
576/// Match a value, capturing it if we match.
577inline bind_ty<Value> m_Value(Value *&V) { return V; }
578inline bind_ty<const Value> m_Value(const Value *&V) { return V; }
579
580/// Match an instruction, capturing it if we match.
581inline bind_ty<Instruction> m_Instruction(Instruction *&I) { return I; }
582/// Match a binary operator, capturing it if we match.
583inline bind_ty<BinaryOperator> m_BinOp(BinaryOperator *&I) { return I; }
584/// Match a with overflow intrinsic, capturing it if we match.
585inline bind_ty<WithOverflowInst> m_WithOverflowInst(WithOverflowInst *&I) { return I; }
586
587/// Match a ConstantInt, capturing the value if we match.
588inline bind_ty<ConstantInt> m_ConstantInt(ConstantInt *&CI) { return CI; }
589
590/// Match a Constant, capturing the value if we match.
591inline bind_ty<Constant> m_Constant(Constant *&C) { return C; }
592
593/// Match a ConstantFP, capturing the value if we match.
594inline bind_ty<ConstantFP> m_ConstantFP(ConstantFP *&C) { return C; }
595
596/// Match a basic block value, capturing it if we match.
597inline bind_ty<BasicBlock> m_BasicBlock(BasicBlock *&V) { return V; }
598inline bind_ty<const BasicBlock> m_BasicBlock(const BasicBlock *&V) {
599 return V;
600}
601
602/// Match a specified Value*.
603struct specificval_ty {
604 const Value *Val;
605
606 specificval_ty(const Value *V) : Val(V) {}
607
608 template <typename ITy> bool match(ITy *V) { return V == Val; }
609};
610
611/// Match if we have a specific specified value.
612inline specificval_ty m_Specific(const Value *V) { return V; }
613
614/// Stores a reference to the Value *, not the Value * itself,
615/// thus can be used in commutative matchers.
616template <typename Class> struct deferredval_ty {
617 Class *const &Val;
618
619 deferredval_ty(Class *const &V) : Val(V) {}
620
621 template <typename ITy> bool match(ITy *const V) { return V == Val; }
622};
623
624/// A commutative-friendly version of m_Specific().
625inline deferredval_ty<Value> m_Deferred(Value *const &V) { return V; }
626inline deferredval_ty<const Value> m_Deferred(const Value *const &V) {
627 return V;
628}
629
630/// Match a specified floating point value or vector of all elements of
631/// that value.
632struct specific_fpval {
633 double Val;
634
635 specific_fpval(double V) : Val(V) {}
636
637 template <typename ITy> bool match(ITy *V) {
638 if (const auto *CFP = dyn_cast<ConstantFP>(V))
639 return CFP->isExactlyValue(Val);
640 if (V->getType()->isVectorTy())
641 if (const auto *C = dyn_cast<Constant>(V))
642 if (auto *CFP = dyn_cast_or_null<ConstantFP>(C->getSplatValue()))
643 return CFP->isExactlyValue(Val);
644 return false;
645 }
646};
647
648/// Match a specific floating point value or vector with all elements
649/// equal to the value.
650inline specific_fpval m_SpecificFP(double V) { return specific_fpval(V); }
651
652/// Match a float 1.0 or vector with all elements equal to 1.0.
653inline specific_fpval m_FPOne() { return m_SpecificFP(1.0); }
654
655struct bind_const_intval_ty {
656 uint64_t &VR;
657
658 bind_const_intval_ty(uint64_t &V) : VR(V) {}
659
660 template <typename ITy> bool match(ITy *V) {
661 if (const auto *CV = dyn_cast<ConstantInt>(V))
662 if (CV->getValue().ule(UINT64_MAX(18446744073709551615UL))) {
663 VR = CV->getZExtValue();
664 return true;
665 }
666 return false;
667 }
668};
669
670/// Match a specified integer value or vector of all elements of that
671/// value.
672struct specific_intval {
673 APInt Val;
674
675 specific_intval(APInt V) : Val(std::move(V)) {}
676
677 template <typename ITy> bool match(ITy *V) {
678 const auto *CI = dyn_cast<ConstantInt>(V);
679 if (!CI && V->getType()->isVectorTy())
680 if (const auto *C = dyn_cast<Constant>(V))
681 CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue());
682
683 return CI && APInt::isSameValue(CI->getValue(), Val);
684 }
685};
686
687/// Match a specific integer value or vector with all elements equal to
688/// the value.
689inline specific_intval m_SpecificInt(APInt V) {
690 return specific_intval(std::move(V));
691}
692
693inline specific_intval m_SpecificInt(uint64_t V) {
694 return m_SpecificInt(APInt(64, V));
695}
696
697/// Match a ConstantInt and bind to its value. This does not match
698/// ConstantInts wider than 64-bits.
699inline bind_const_intval_ty m_ConstantInt(uint64_t &V) { return V; }
700
701/// Match a specified basic block value.
702struct specific_bbval {
703 BasicBlock *Val;
704
705 specific_bbval(BasicBlock *Val) : Val(Val) {}
706
707 template <typename ITy> bool match(ITy *V) {
708 const auto *BB = dyn_cast<BasicBlock>(V);
709 return BB && BB == Val;
710 }
711};
712
713/// Match a specific basic block value.
714inline specific_bbval m_SpecificBB(BasicBlock *BB) {
715 return specific_bbval(BB);
716}
717
718/// A commutative-friendly version of m_Specific().
719inline deferredval_ty<BasicBlock> m_Deferred(BasicBlock *const &BB) {
720 return BB;
721}
722inline deferredval_ty<const BasicBlock>
723m_Deferred(const BasicBlock *const &BB) {
724 return BB;
725}
726
727//===----------------------------------------------------------------------===//
728// Matcher for any binary operator.
729//
730template <typename LHS_t, typename RHS_t, bool Commutable = false>
731struct AnyBinaryOp_match {
732 LHS_t L;
733 RHS_t R;
734
735 // The evaluation order is always stable, regardless of Commutability.
736 // The LHS is always matched first.
737 AnyBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
738
739 template <typename OpTy> bool match(OpTy *V) {
740 if (auto *I = dyn_cast<BinaryOperator>(V))
741 return (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
742 (Commutable && L.match(I->getOperand(1)) &&
743 R.match(I->getOperand(0)));
744 return false;
745 }
746};
747
748template <typename LHS, typename RHS>
749inline AnyBinaryOp_match<LHS, RHS> m_BinOp(const LHS &L, const RHS &R) {
750 return AnyBinaryOp_match<LHS, RHS>(L, R);
751}
752
753//===----------------------------------------------------------------------===//
754// Matchers for specific binary operators.
755//
756
757template <typename LHS_t, typename RHS_t, unsigned Opcode,
758 bool Commutable = false>
759struct BinaryOp_match {
760 LHS_t L;
761 RHS_t R;
762
763 // The evaluation order is always stable, regardless of Commutability.
764 // The LHS is always matched first.
765 BinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
766
767 template <typename OpTy> bool match(OpTy *V) {
768 if (V->getValueID() == Value::InstructionVal + Opcode) {
769 auto *I = cast<BinaryOperator>(V);
770 return (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
771 (Commutable && L.match(I->getOperand(1)) &&
772 R.match(I->getOperand(0)));
773 }
774 if (auto *CE = dyn_cast<ConstantExpr>(V))
775 return CE->getOpcode() == Opcode &&
776 ((L.match(CE->getOperand(0)) && R.match(CE->getOperand(1))) ||
777 (Commutable && L.match(CE->getOperand(1)) &&
778 R.match(CE->getOperand(0))));
779 return false;
780 }
781};
782
783template <typename LHS, typename RHS>
784inline BinaryOp_match<LHS, RHS, Instruction::Add> m_Add(const LHS &L,
785 const RHS &R) {
786 return BinaryOp_match<LHS, RHS, Instruction::Add>(L, R);
787}
788
789template <typename LHS, typename RHS>
790inline BinaryOp_match<LHS, RHS, Instruction::FAdd> m_FAdd(const LHS &L,
791 const RHS &R) {
792 return BinaryOp_match<LHS, RHS, Instruction::FAdd>(L, R);
793}
794
795template <typename LHS, typename RHS>
796inline BinaryOp_match<LHS, RHS, Instruction::Sub> m_Sub(const LHS &L,
797 const RHS &R) {
798 return BinaryOp_match<LHS, RHS, Instruction::Sub>(L, R);
799}
800
801template <typename LHS, typename RHS>
802inline BinaryOp_match<LHS, RHS, Instruction::FSub> m_FSub(const LHS &L,
803 const RHS &R) {
804 return BinaryOp_match<LHS, RHS, Instruction::FSub>(L, R);
805}
806
807template <typename Op_t> struct FNeg_match {
808 Op_t X;
809
810 FNeg_match(const Op_t &Op) : X(Op) {}
811 template <typename OpTy> bool match(OpTy *V) {
812 auto *FPMO = dyn_cast<FPMathOperator>(V);
813 if (!FPMO) return false;
814
815 if (FPMO->getOpcode() == Instruction::FNeg)
816 return X.match(FPMO->getOperand(0));
817
818 if (FPMO->getOpcode() == Instruction::FSub) {
819 if (FPMO->hasNoSignedZeros()) {
820 // With 'nsz', any zero goes.
821 if (!cstfp_pred_ty<is_any_zero_fp>().match(FPMO->getOperand(0)))
822 return false;
823 } else {
824 // Without 'nsz', we need fsub -0.0, X exactly.
825 if (!cstfp_pred_ty<is_neg_zero_fp>().match(FPMO->getOperand(0)))
826 return false;
827 }
828
829 return X.match(FPMO->getOperand(1));
830 }
831
832 return false;
833 }
834};
835
836/// Match 'fneg X' as 'fsub -0.0, X'.
837template <typename OpTy>
838inline FNeg_match<OpTy>
839m_FNeg(const OpTy &X) {
840 return FNeg_match<OpTy>(X);
841}
842
843/// Match 'fneg X' as 'fsub +-0.0, X'.
844template <typename RHS>
845inline BinaryOp_match<cstfp_pred_ty<is_any_zero_fp>, RHS, Instruction::FSub>
846m_FNegNSZ(const RHS &X) {
847 return m_FSub(m_AnyZeroFP(), X);
848}
849
850template <typename LHS, typename RHS>
851inline BinaryOp_match<LHS, RHS, Instruction::Mul> m_Mul(const LHS &L,
852 const RHS &R) {
853 return BinaryOp_match<LHS, RHS, Instruction::Mul>(L, R);
854}
855
856template <typename LHS, typename RHS>
857inline BinaryOp_match<LHS, RHS, Instruction::FMul> m_FMul(const LHS &L,
858 const RHS &R) {
859 return BinaryOp_match<LHS, RHS, Instruction::FMul>(L, R);
860}
861
862template <typename LHS, typename RHS>
863inline BinaryOp_match<LHS, RHS, Instruction::UDiv> m_UDiv(const LHS &L,
864 const RHS &R) {
865 return BinaryOp_match<LHS, RHS, Instruction::UDiv>(L, R);
866}
867
868template <typename LHS, typename RHS>
869inline BinaryOp_match<LHS, RHS, Instruction::SDiv> m_SDiv(const LHS &L,
870 const RHS &R) {
871 return BinaryOp_match<LHS, RHS, Instruction::SDiv>(L, R);
872}
873
874template <typename LHS, typename RHS>
875inline BinaryOp_match<LHS, RHS, Instruction::FDiv> m_FDiv(const LHS &L,
876 const RHS &R) {
877 return BinaryOp_match<LHS, RHS, Instruction::FDiv>(L, R);
878}
879
880template <typename LHS, typename RHS>
881inline BinaryOp_match<LHS, RHS, Instruction::URem> m_URem(const LHS &L,
882 const RHS &R) {
883 return BinaryOp_match<LHS, RHS, Instruction::URem>(L, R);
884}
885
886template <typename LHS, typename RHS>
887inline BinaryOp_match<LHS, RHS, Instruction::SRem> m_SRem(const LHS &L,
888 const RHS &R) {
889 return BinaryOp_match<LHS, RHS, Instruction::SRem>(L, R);
890}
891
892template <typename LHS, typename RHS>
893inline BinaryOp_match<LHS, RHS, Instruction::FRem> m_FRem(const LHS &L,
894 const RHS &R) {
895 return BinaryOp_match<LHS, RHS, Instruction::FRem>(L, R);
896}
897
898template <typename LHS, typename RHS>
899inline BinaryOp_match<LHS, RHS, Instruction::And> m_And(const LHS &L,
900 const RHS &R) {
901 return BinaryOp_match<LHS, RHS, Instruction::And>(L, R);
902}
903
904template <typename LHS, typename RHS>
905inline BinaryOp_match<LHS, RHS, Instruction::Or> m_Or(const LHS &L,
906 const RHS &R) {
907 return BinaryOp_match<LHS, RHS, Instruction::Or>(L, R);
908}
909
910template <typename LHS, typename RHS>
911inline BinaryOp_match<LHS, RHS, Instruction::Xor> m_Xor(const LHS &L,
912 const RHS &R) {
913 return BinaryOp_match<LHS, RHS, Instruction::Xor>(L, R);
914}
915
916template <typename LHS, typename RHS>
917inline BinaryOp_match<LHS, RHS, Instruction::Shl> m_Shl(const LHS &L,
918 const RHS &R) {
919 return BinaryOp_match<LHS, RHS, Instruction::Shl>(L, R);
920}
921
922template <typename LHS, typename RHS>
923inline BinaryOp_match<LHS, RHS, Instruction::LShr> m_LShr(const LHS &L,
924 const RHS &R) {
925 return BinaryOp_match<LHS, RHS, Instruction::LShr>(L, R);
926}
927
928template <typename LHS, typename RHS>
929inline BinaryOp_match<LHS, RHS, Instruction::AShr> m_AShr(const LHS &L,
930 const RHS &R) {
931 return BinaryOp_match<LHS, RHS, Instruction::AShr>(L, R);
932}
933
934template <typename LHS_t, typename RHS_t, unsigned Opcode,
935 unsigned WrapFlags = 0>
936struct OverflowingBinaryOp_match {
937 LHS_t L;
938 RHS_t R;
939
940 OverflowingBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS)
941 : L(LHS), R(RHS) {}
942
943 template <typename OpTy> bool match(OpTy *V) {
944 if (auto *Op = dyn_cast<OverflowingBinaryOperator>(V)) {
945 if (Op->getOpcode() != Opcode)
946 return false;
947 if (WrapFlags & OverflowingBinaryOperator::NoUnsignedWrap &&
948 !Op->hasNoUnsignedWrap())
949 return false;
950 if (WrapFlags & OverflowingBinaryOperator::NoSignedWrap &&
951 !Op->hasNoSignedWrap())
952 return false;
953 return L.match(Op->getOperand(0)) && R.match(Op->getOperand(1));
954 }
955 return false;
956 }
957};
958
959template <typename LHS, typename RHS>
960inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
961 OverflowingBinaryOperator::NoSignedWrap>
962m_NSWAdd(const LHS &L, const RHS &R) {
963 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
964 OverflowingBinaryOperator::NoSignedWrap>(
965 L, R);
966}
967template <typename LHS, typename RHS>
968inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
969 OverflowingBinaryOperator::NoSignedWrap>
970m_NSWSub(const LHS &L, const RHS &R) {
971 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
972 OverflowingBinaryOperator::NoSignedWrap>(
973 L, R);
974}
975template <typename LHS, typename RHS>
976inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
977 OverflowingBinaryOperator::NoSignedWrap>
978m_NSWMul(const LHS &L, const RHS &R) {
979 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
980 OverflowingBinaryOperator::NoSignedWrap>(
981 L, R);
982}
983template <typename LHS, typename RHS>
984inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
985 OverflowingBinaryOperator::NoSignedWrap>
986m_NSWShl(const LHS &L, const RHS &R) {
987 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
988 OverflowingBinaryOperator::NoSignedWrap>(
989 L, R);
990}
991
992template <typename LHS, typename RHS>
993inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
994 OverflowingBinaryOperator::NoUnsignedWrap>
995m_NUWAdd(const LHS &L, const RHS &R) {
996 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
997 OverflowingBinaryOperator::NoUnsignedWrap>(
998 L, R);
999}
1000template <typename LHS, typename RHS>
1001inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
1002 OverflowingBinaryOperator::NoUnsignedWrap>
1003m_NUWSub(const LHS &L, const RHS &R) {
1004 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
1005 OverflowingBinaryOperator::NoUnsignedWrap>(
1006 L, R);
1007}
1008template <typename LHS, typename RHS>
1009inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
1010 OverflowingBinaryOperator::NoUnsignedWrap>
1011m_NUWMul(const LHS &L, const RHS &R) {
1012 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
1013 OverflowingBinaryOperator::NoUnsignedWrap>(
1014 L, R);
1015}
1016template <typename LHS, typename RHS>
1017inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
1018 OverflowingBinaryOperator::NoUnsignedWrap>
1019m_NUWShl(const LHS &L, const RHS &R) {
1020 return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
1021 OverflowingBinaryOperator::NoUnsignedWrap>(
1022 L, R);
1023}
1024
1025//===----------------------------------------------------------------------===//
1026// Class that matches a group of binary opcodes.
1027//
1028template <typename LHS_t, typename RHS_t, typename Predicate>
1029struct BinOpPred_match : Predicate {
1030 LHS_t L;
1031 RHS_t R;
1032
1033 BinOpPred_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
1034
1035 template <typename OpTy> bool match(OpTy *V) {
1036 if (auto *I = dyn_cast<Instruction>(V))
1037 return this->isOpType(I->getOpcode()) && L.match(I->getOperand(0)) &&
1038 R.match(I->getOperand(1));
1039 if (auto *CE = dyn_cast<ConstantExpr>(V))
1040 return this->isOpType(CE->getOpcode()) && L.match(CE->getOperand(0)) &&
1041 R.match(CE->getOperand(1));
1042 return false;
1043 }
1044};
1045
1046struct is_shift_op {
1047 bool isOpType(unsigned Opcode) { return Instruction::isShift(Opcode); }
1048};
1049
1050struct is_right_shift_op {
1051 bool isOpType(unsigned Opcode) {
1052 return Opcode == Instruction::LShr || Opcode == Instruction::AShr;
1053 }
1054};
1055
1056struct is_logical_shift_op {
1057 bool isOpType(unsigned Opcode) {
1058 return Opcode == Instruction::LShr || Opcode == Instruction::Shl;
1059 }
1060};
1061
1062struct is_bitwiselogic_op {
1063 bool isOpType(unsigned Opcode) {
1064 return Instruction::isBitwiseLogicOp(Opcode);
1065 }
1066};
1067
1068struct is_idiv_op {
1069 bool isOpType(unsigned Opcode) {
1070 return Opcode == Instruction::SDiv || Opcode == Instruction::UDiv;
1071 }
1072};
1073
1074struct is_irem_op {
1075 bool isOpType(unsigned Opcode) {
1076 return Opcode == Instruction::SRem || Opcode == Instruction::URem;
1077 }
1078};
1079
1080/// Matches shift operations.
1081template <typename LHS, typename RHS>
1082inline BinOpPred_match<LHS, RHS, is_shift_op> m_Shift(const LHS &L,
1083 const RHS &R) {
1084 return BinOpPred_match<LHS, RHS, is_shift_op>(L, R);
1085}
1086
1087/// Matches logical shift operations.
1088template <typename LHS, typename RHS>
1089inline BinOpPred_match<LHS, RHS, is_right_shift_op> m_Shr(const LHS &L,
1090 const RHS &R) {
1091 return BinOpPred_match<LHS, RHS, is_right_shift_op>(L, R);
1092}
1093
1094/// Matches logical shift operations.
1095template <typename LHS, typename RHS>
1096inline BinOpPred_match<LHS, RHS, is_logical_shift_op>
1097m_LogicalShift(const LHS &L, const RHS &R) {
1098 return BinOpPred_match<LHS, RHS, is_logical_shift_op>(L, R);
1099}
1100
1101/// Matches bitwise logic operations.
1102template <typename LHS, typename RHS>
1103inline BinOpPred_match<LHS, RHS, is_bitwiselogic_op>
1104m_BitwiseLogic(const LHS &L, const RHS &R) {
1105 return BinOpPred_match<LHS, RHS, is_bitwiselogic_op>(L, R);
1106}
1107
1108/// Matches integer division operations.
1109template <typename LHS, typename RHS>
1110inline BinOpPred_match<LHS, RHS, is_idiv_op> m_IDiv(const LHS &L,
1111 const RHS &R) {
1112 return BinOpPred_match<LHS, RHS, is_idiv_op>(L, R);
1113}
1114
1115/// Matches integer remainder operations.
1116template <typename LHS, typename RHS>
1117inline BinOpPred_match<LHS, RHS, is_irem_op> m_IRem(const LHS &L,
1118 const RHS &R) {
1119 return BinOpPred_match<LHS, RHS, is_irem_op>(L, R);
1120}
1121
1122//===----------------------------------------------------------------------===//
1123// Class that matches exact binary ops.
1124//
1125template <typename SubPattern_t> struct Exact_match {
1126 SubPattern_t SubPattern;
1127
1128 Exact_match(const SubPattern_t &SP) : SubPattern(SP) {}
1129
1130 template <typename OpTy> bool match(OpTy *V) {
1131 if (auto *PEO = dyn_cast<PossiblyExactOperator>(V))
1132 return PEO->isExact() && SubPattern.match(V);
1133 return false;
1134 }
1135};
1136
1137template <typename T> inline Exact_match<T> m_Exact(const T &SubPattern) {
1138 return SubPattern;
1139}
1140
1141//===----------------------------------------------------------------------===//
1142// Matchers for CmpInst classes
1143//
1144
1145template <typename LHS_t, typename RHS_t, typename Class, typename PredicateTy,
1146 bool Commutable = false>
1147struct CmpClass_match {
1148 PredicateTy &Predicate;
1149 LHS_t L;
1150 RHS_t R;
1151
1152 // The evaluation order is always stable, regardless of Commutability.
1153 // The LHS is always matched first.
1154 CmpClass_match(PredicateTy &Pred, const LHS_t &LHS, const RHS_t &RHS)
1155 : Predicate(Pred), L(LHS), R(RHS) {}
1156
1157 template <typename OpTy> bool match(OpTy *V) {
1158 if (auto *I = dyn_cast<Class>(V))
1159 if ((L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
1160 (Commutable && L.match(I->getOperand(1)) &&
1161 R.match(I->getOperand(0)))) {
1162 Predicate = I->getPredicate();
1163 return true;
1164 }
1165 return false;
1166 }
1167};
1168
1169template <typename LHS, typename RHS>
1170inline CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>
1171m_Cmp(CmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1172 return CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>(Pred, L, R);
1173}
1174
1175template <typename LHS, typename RHS>
1176inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>
1177m_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1178 return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>(Pred, L, R);
1179}
1180
1181template <typename LHS, typename RHS>
1182inline CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>
1183m_FCmp(FCmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1184 return CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>(Pred, L, R);
1185}
1186
1187//===----------------------------------------------------------------------===//
1188// Matchers for instructions with a given opcode and number of operands.
1189//
1190
1191/// Matches instructions with Opcode and three operands.
1192template <typename T0, unsigned Opcode> struct OneOps_match {
1193 T0 Op1;
1194
1195 OneOps_match(const T0 &Op1) : Op1(Op1) {}
1196
1197 template <typename OpTy> bool match(OpTy *V) {
1198 if (V->getValueID() == Value::InstructionVal + Opcode) {
1199 auto *I = cast<Instruction>(V);
1200 return Op1.match(I->getOperand(0));
1201 }
1202 return false;
1203 }
1204};
1205
1206/// Matches instructions with Opcode and three operands.
1207template <typename T0, typename T1, unsigned Opcode> struct TwoOps_match {
1208 T0 Op1;
1209 T1 Op2;
1210
1211 TwoOps_match(const T0 &Op1, const T1 &Op2) : Op1(Op1), Op2(Op2) {}
1212
1213 template <typename OpTy> bool match(OpTy *V) {
1214 if (V->getValueID() == Value::InstructionVal + Opcode) {
1215 auto *I = cast<Instruction>(V);
1216 return Op1.match(I->getOperand(0)) && Op2.match(I->getOperand(1));
1217 }
1218 return false;
1219 }
1220};
1221
1222/// Matches instructions with Opcode and three operands.
1223template <typename T0, typename T1, typename T2, unsigned Opcode>
1224struct ThreeOps_match {
1225 T0 Op1;
1226 T1 Op2;
1227 T2 Op3;
1228
1229 ThreeOps_match(const T0 &Op1, const T1 &Op2, const T2 &Op3)
1230 : Op1(Op1), Op2(Op2), Op3(Op3) {}
1231
1232 template <typename OpTy> bool match(OpTy *V) {
1233 if (V->getValueID() == Value::InstructionVal + Opcode) {
1234 auto *I = cast<Instruction>(V);
1235 return Op1.match(I->getOperand(0)) && Op2.match(I->getOperand(1)) &&
1236 Op3.match(I->getOperand(2));
1237 }
1238 return false;
1239 }
1240};
1241
1242/// Matches SelectInst.
1243template <typename Cond, typename LHS, typename RHS>
1244inline ThreeOps_match<Cond, LHS, RHS, Instruction::Select>
1245m_Select(const Cond &C, const LHS &L, const RHS &R) {
1246 return ThreeOps_match<Cond, LHS, RHS, Instruction::Select>(C, L, R);
1247}
1248
1249/// This matches a select of two constants, e.g.:
1250/// m_SelectCst<-1, 0>(m_Value(V))
1251template <int64_t L, int64_t R, typename Cond>
1252inline ThreeOps_match<Cond, constantint_match<L>, constantint_match<R>,
1253 Instruction::Select>
1254m_SelectCst(const Cond &C) {
1255 return m_Select(C, m_ConstantInt<L>(), m_ConstantInt<R>());
1256}
1257
1258/// Matches FreezeInst.
1259template <typename OpTy>
1260inline OneOps_match<OpTy, Instruction::Freeze> m_Freeze(const OpTy &Op) {
1261 return OneOps_match<OpTy, Instruction::Freeze>(Op);
1262}
1263
1264/// Matches InsertElementInst.
1265template <typename Val_t, typename Elt_t, typename Idx_t>
1266inline ThreeOps_match<Val_t, Elt_t, Idx_t, Instruction::InsertElement>
1267m_InsertElement(const Val_t &Val, const Elt_t &Elt, const Idx_t &Idx) {
1268 return ThreeOps_match<Val_t, Elt_t, Idx_t, Instruction::InsertElement>(
1269 Val, Elt, Idx);
1270}
1271
1272/// Matches ExtractElementInst.
1273template <typename Val_t, typename Idx_t>
1274inline TwoOps_match<Val_t, Idx_t, Instruction::ExtractElement>
1275m_ExtractElement(const Val_t &Val, const Idx_t &Idx) {
1276 return TwoOps_match<Val_t, Idx_t, Instruction::ExtractElement>(Val, Idx);
1277}
1278
1279/// Matches ShuffleVectorInst.
1280template <typename V1_t, typename V2_t, typename Mask_t>
1281inline ThreeOps_match<V1_t, V2_t, Mask_t, Instruction::ShuffleVector>
1282m_ShuffleVector(const V1_t &v1, const V2_t &v2, const Mask_t &m) {
1283 return ThreeOps_match<V1_t, V2_t, Mask_t, Instruction::ShuffleVector>(v1, v2,
1284 m);
1285}
1286
1287/// Matches LoadInst.
1288template <typename OpTy>
1289inline OneOps_match<OpTy, Instruction::Load> m_Load(const OpTy &Op) {
1290 return OneOps_match<OpTy, Instruction::Load>(Op);
1291}
1292
1293/// Matches StoreInst.
1294template <typename ValueOpTy, typename PointerOpTy>
1295inline TwoOps_match<ValueOpTy, PointerOpTy, Instruction::Store>
1296m_Store(const ValueOpTy &ValueOp, const PointerOpTy &PointerOp) {
1297 return TwoOps_match<ValueOpTy, PointerOpTy, Instruction::Store>(ValueOp,
1298 PointerOp);
1299}
1300
1301//===----------------------------------------------------------------------===//
1302// Matchers for CastInst classes
1303//
1304
1305template <typename Op_t, unsigned Opcode> struct CastClass_match {
1306 Op_t Op;
1307
1308 CastClass_match(const Op_t &OpMatch) : Op(OpMatch) {}
1309
1310 template <typename OpTy> bool match(OpTy *V) {
1311 if (auto *O = dyn_cast<Operator>(V))
1312 return O->getOpcode() == Opcode && Op.match(O->getOperand(0));
1313 return false;
1314 }
1315};
1316
1317/// Matches BitCast.
1318template <typename OpTy>
1319inline CastClass_match<OpTy, Instruction::BitCast> m_BitCast(const OpTy &Op) {
1320 return CastClass_match<OpTy, Instruction::BitCast>(Op);
1321}
1322
1323/// Matches PtrToInt.
1324template <typename OpTy>
1325inline CastClass_match<OpTy, Instruction::PtrToInt> m_PtrToInt(const OpTy &Op) {
1326 return CastClass_match<OpTy, Instruction::PtrToInt>(Op);
1327}
1328
1329/// Matches Trunc.
1330template <typename OpTy>
1331inline CastClass_match<OpTy, Instruction::Trunc> m_Trunc(const OpTy &Op) {
1332 return CastClass_match<OpTy, Instruction::Trunc>(Op);
1333}
1334
1335template <typename OpTy>
1336inline match_combine_or<CastClass_match<OpTy, Instruction::Trunc>, OpTy>
1337m_TruncOrSelf(const OpTy &Op) {
1338 return m_CombineOr(m_Trunc(Op), Op);
1339}
1340
1341/// Matches SExt.
1342template <typename OpTy>
1343inline CastClass_match<OpTy, Instruction::SExt> m_SExt(const OpTy &Op) {
1344 return CastClass_match<OpTy, Instruction::SExt>(Op);
1345}
1346
1347/// Matches ZExt.
1348template <typename OpTy>
1349inline CastClass_match<OpTy, Instruction::ZExt> m_ZExt(const OpTy &Op) {
1350 return CastClass_match<OpTy, Instruction::ZExt>(Op);
1351}
1352
1353template <typename OpTy>
1354inline match_combine_or<CastClass_match<OpTy, Instruction::ZExt>, OpTy>
1355m_ZExtOrSelf(const OpTy &Op) {
1356 return m_CombineOr(m_ZExt(Op), Op);
1357}
1358
1359template <typename OpTy>
1360inline match_combine_or<CastClass_match<OpTy, Instruction::SExt>, OpTy>
1361m_SExtOrSelf(const OpTy &Op) {
1362 return m_CombineOr(m_SExt(Op), Op);
1363}
1364
1365template <typename OpTy>
1366inline match_combine_or<CastClass_match<OpTy, Instruction::ZExt>,
1367 CastClass_match<OpTy, Instruction::SExt>>
1368m_ZExtOrSExt(const OpTy &Op) {
1369 return m_CombineOr(m_ZExt(Op), m_SExt(Op));
1370}
1371
1372template <typename OpTy>
1373inline match_combine_or<
1374 match_combine_or<CastClass_match<OpTy, Instruction::ZExt>,
1375 CastClass_match<OpTy, Instruction::SExt>>,
1376 OpTy>
1377m_ZExtOrSExtOrSelf(const OpTy &Op) {
1378 return m_CombineOr(m_ZExtOrSExt(Op), Op);
1379}
1380
1381/// Matches UIToFP.
1382template <typename OpTy>
1383inline CastClass_match<OpTy, Instruction::UIToFP> m_UIToFP(const OpTy &Op) {
1384 return CastClass_match<OpTy, Instruction::UIToFP>(Op);
1385}
1386
1387/// Matches SIToFP.
1388template <typename OpTy>
1389inline CastClass_match<OpTy, Instruction::SIToFP> m_SIToFP(const OpTy &Op) {
1390 return CastClass_match<OpTy, Instruction::SIToFP>(Op);
1391}
1392
1393/// Matches FPTrunc
1394template <typename OpTy>
1395inline CastClass_match<OpTy, Instruction::FPTrunc> m_FPTrunc(const OpTy &Op) {
1396 return CastClass_match<OpTy, Instruction::FPTrunc>(Op);
1397}
1398
1399/// Matches FPExt
1400template <typename OpTy>
1401inline CastClass_match<OpTy, Instruction::FPExt> m_FPExt(const OpTy &Op) {
1402 return CastClass_match<OpTy, Instruction::FPExt>(Op);
1403}
1404
1405//===----------------------------------------------------------------------===//
1406// Matchers for control flow.
1407//
1408
1409struct br_match {
1410 BasicBlock *&Succ;
1411
1412 br_match(BasicBlock *&Succ) : Succ(Succ) {}
1413
1414 template <typename OpTy> bool match(OpTy *V) {
1415 if (auto *BI = dyn_cast<BranchInst>(V))
1416 if (BI->isUnconditional()) {
1417 Succ = BI->getSuccessor(0);
1418 return true;
1419 }
1420 return false;
1421 }
1422};
1423
1424inline br_match m_UnconditionalBr(BasicBlock *&Succ) { return br_match(Succ); }
1425
1426template <typename Cond_t, typename TrueBlock_t, typename FalseBlock_t>
1427struct brc_match {
1428 Cond_t Cond;
1429 TrueBlock_t T;
1430 FalseBlock_t F;
1431
1432 brc_match(const Cond_t &C, const TrueBlock_t &t, const FalseBlock_t &f)
1433 : Cond(C), T(t), F(f) {}
1434
1435 template <typename OpTy> bool match(OpTy *V) {
1436 if (auto *BI = dyn_cast<BranchInst>(V))
1437 if (BI->isConditional() && Cond.match(BI->getCondition()))
1438 return T.match(BI->getSuccessor(0)) && F.match(BI->getSuccessor(1));
1439 return false;
1440 }
1441};
1442
1443template <typename Cond_t>
1444inline brc_match<Cond_t, bind_ty<BasicBlock>, bind_ty<BasicBlock>>
1445m_Br(const Cond_t &C, BasicBlock *&T, BasicBlock *&F) {
1446 return brc_match<Cond_t, bind_ty<BasicBlock>, bind_ty<BasicBlock>>(
1447 C, m_BasicBlock(T), m_BasicBlock(F));
1448}
1449
1450template <typename Cond_t, typename TrueBlock_t, typename FalseBlock_t>
1451inline brc_match<Cond_t, TrueBlock_t, FalseBlock_t>
1452m_Br(const Cond_t &C, const TrueBlock_t &T, const FalseBlock_t &F) {
1453 return brc_match<Cond_t, TrueBlock_t, FalseBlock_t>(C, T, F);
1454}
1455
1456//===----------------------------------------------------------------------===//
1457// Matchers for max/min idioms, eg: "select (sgt x, y), x, y" -> smax(x,y).
1458//
1459
1460template <typename CmpInst_t, typename LHS_t, typename RHS_t, typename Pred_t,
1461 bool Commutable = false>
1462struct MaxMin_match {
1463 LHS_t L;
1464 RHS_t R;
1465
1466 // The evaluation order is always stable, regardless of Commutability.
1467 // The LHS is always matched first.
1468 MaxMin_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
1469
1470 template <typename OpTy> bool match(OpTy *V) {
1471 // Look for "(x pred y) ? x : y" or "(x pred y) ? y : x".
1472 auto *SI = dyn_cast<SelectInst>(V);
1473 if (!SI)
1474 return false;
1475 auto *Cmp = dyn_cast<CmpInst_t>(SI->getCondition());
1476 if (!Cmp)
1477 return false;
1478 // At this point we have a select conditioned on a comparison. Check that
1479 // it is the values returned by the select that are being compared.
1480 Value *TrueVal = SI->getTrueValue();
1481 Value *FalseVal = SI->getFalseValue();
1482 Value *LHS = Cmp->getOperand(0);
1483 Value *RHS = Cmp->getOperand(1);
1484 if ((TrueVal != LHS || FalseVal != RHS) &&
1485 (TrueVal != RHS || FalseVal != LHS))
1486 return false;
1487 typename CmpInst_t::Predicate Pred =
1488 LHS == TrueVal ? Cmp->getPredicate() : Cmp->getInversePredicate();
1489 // Does "(x pred y) ? x : y" represent the desired max/min operation?
1490 if (!Pred_t::match(Pred))
1491 return false;
1492 // It does! Bind the operands.
1493 return (L.match(LHS) && R.match(RHS)) ||
1494 (Commutable && L.match(RHS) && R.match(LHS));
1495 }
1496};
1497
1498/// Helper class for identifying signed max predicates.
1499struct smax_pred_ty {
1500 static bool match(ICmpInst::Predicate Pred) {
1501 return Pred == CmpInst::ICMP_SGT || Pred == CmpInst::ICMP_SGE;
1502 }
1503};
1504
1505/// Helper class for identifying signed min predicates.
1506struct smin_pred_ty {
1507 static bool match(ICmpInst::Predicate Pred) {
1508 return Pred == CmpInst::ICMP_SLT || Pred == CmpInst::ICMP_SLE;
1509 }
1510};
1511
1512/// Helper class for identifying unsigned max predicates.
1513struct umax_pred_ty {
1514 static bool match(ICmpInst::Predicate Pred) {
1515 return Pred == CmpInst::ICMP_UGT || Pred == CmpInst::ICMP_UGE;
1516 }
1517};
1518
1519/// Helper class for identifying unsigned min predicates.
1520struct umin_pred_ty {
1521 static bool match(ICmpInst::Predicate Pred) {
1522 return Pred == CmpInst::ICMP_ULT || Pred == CmpInst::ICMP_ULE;
1523 }
1524};
1525
1526/// Helper class for identifying ordered max predicates.
1527struct ofmax_pred_ty {
1528 static bool match(FCmpInst::Predicate Pred) {
1529 return Pred == CmpInst::FCMP_OGT || Pred == CmpInst::FCMP_OGE;
1530 }
1531};
1532
1533/// Helper class for identifying ordered min predicates.
1534struct ofmin_pred_ty {
1535 static bool match(FCmpInst::Predicate Pred) {
1536 return Pred == CmpInst::FCMP_OLT || Pred == CmpInst::FCMP_OLE;
1537 }
1538};
1539
1540/// Helper class for identifying unordered max predicates.
1541struct ufmax_pred_ty {
1542 static bool match(FCmpInst::Predicate Pred) {
1543 return Pred == CmpInst::FCMP_UGT || Pred == CmpInst::FCMP_UGE;
1544 }
1545};
1546
1547/// Helper class for identifying unordered min predicates.
1548struct ufmin_pred_ty {
1549 static bool match(FCmpInst::Predicate Pred) {
1550 return Pred == CmpInst::FCMP_ULT || Pred == CmpInst::FCMP_ULE;
1551 }
1552};
1553
1554template <typename LHS, typename RHS>
1555inline MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty> m_SMax(const LHS &L,
1556 const RHS &R) {
1557 return MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty>(L, R);
1558}
1559
1560template <typename LHS, typename RHS>
1561inline MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty> m_SMin(const LHS &L,
1562 const RHS &R) {
1563 return MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty>(L, R);
1564}
1565
1566template <typename LHS, typename RHS>
1567inline MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty> m_UMax(const LHS &L,
1568 const RHS &R) {
1569 return MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty>(L, R);
1570}
1571
1572template <typename LHS, typename RHS>
1573inline MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty> m_UMin(const LHS &L,
1574 const RHS &R) {
1575 return MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty>(L, R);
1576}
1577
1578/// Match an 'ordered' floating point maximum function.
1579/// Floating point has one special value 'NaN'. Therefore, there is no total
1580/// order. However, if we can ignore the 'NaN' value (for example, because of a
1581/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
1582/// semantics. In the presence of 'NaN' we have to preserve the original
1583/// select(fcmp(ogt/ge, L, R), L, R) semantics matched by this predicate.
1584///
1585/// max(L, R) iff L and R are not NaN
1586/// m_OrdFMax(L, R) = R iff L or R are NaN
1587template <typename LHS, typename RHS>
1588inline MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty> m_OrdFMax(const LHS &L,
1589 const RHS &R) {
1590 return MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty>(L, R);
1591}
1592
1593/// Match an 'ordered' floating point minimum function.
1594/// Floating point has one special value 'NaN'. Therefore, there is no total
1595/// order. However, if we can ignore the 'NaN' value (for example, because of a
1596/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
1597/// semantics. In the presence of 'NaN' we have to preserve the original
1598/// select(fcmp(olt/le, L, R), L, R) semantics matched by this predicate.
1599///
1600/// min(L, R) iff L and R are not NaN
1601/// m_OrdFMin(L, R) = R iff L or R are NaN
1602template <typename LHS, typename RHS>
1603inline MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty> m_OrdFMin(const LHS &L,
1604 const RHS &R) {
1605 return MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty>(L, R);
1606}
1607
1608/// Match an 'unordered' floating point maximum function.
1609/// Floating point has one special value 'NaN'. Therefore, there is no total
1610/// order. However, if we can ignore the 'NaN' value (for example, because of a
1611/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
1612/// semantics. In the presence of 'NaN' we have to preserve the original
1613/// select(fcmp(ugt/ge, L, R), L, R) semantics matched by this predicate.
1614///
1615/// max(L, R) iff L and R are not NaN
1616/// m_UnordFMax(L, R) = L iff L or R are NaN
1617template <typename LHS, typename RHS>
1618inline MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>
1619m_UnordFMax(const LHS &L, const RHS &R) {
1620 return MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>(L, R);
1621}
1622
1623/// Match an 'unordered' floating point minimum function.
1624/// Floating point has one special value 'NaN'. Therefore, there is no total
1625/// order. However, if we can ignore the 'NaN' value (for example, because of a
1626/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
1627/// semantics. In the presence of 'NaN' we have to preserve the original
1628/// select(fcmp(ult/le, L, R), L, R) semantics matched by this predicate.
1629///
1630/// min(L, R) iff L and R are not NaN
1631/// m_UnordFMin(L, R) = L iff L or R are NaN
1632template <typename LHS, typename RHS>
1633inline MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>
1634m_UnordFMin(const LHS &L, const RHS &R) {
1635 return MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>(L, R);
1636}
1637
1638//===----------------------------------------------------------------------===//
1639// Matchers for overflow check patterns: e.g. (a + b) u< a
1640//
1641
1642template <typename LHS_t, typename RHS_t, typename Sum_t>
1643struct UAddWithOverflow_match {
1644 LHS_t L;
1645 RHS_t R;
1646 Sum_t S;
1647
1648 UAddWithOverflow_match(const LHS_t &L, const RHS_t &R, const Sum_t &S)
1649 : L(L), R(R), S(S) {}
1650
1651 template <typename OpTy> bool match(OpTy *V) {
1652 Value *ICmpLHS, *ICmpRHS;
1653 ICmpInst::Predicate Pred;
1654 if (!m_ICmp(Pred, m_Value(ICmpLHS), m_Value(ICmpRHS)).match(V))
1655 return false;
1656
1657 Value *AddLHS, *AddRHS;
1658 auto AddExpr = m_Add(m_Value(AddLHS), m_Value(AddRHS));
1659
1660 // (a + b) u< a, (a + b) u< b
1661 if (Pred == ICmpInst::ICMP_ULT)
1662 if (AddExpr.match(ICmpLHS) && (ICmpRHS == AddLHS || ICmpRHS == AddRHS))
1663 return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
1664
1665 // a >u (a + b), b >u (a + b)
1666 if (Pred == ICmpInst::ICMP_UGT)
1667 if (AddExpr.match(ICmpRHS) && (ICmpLHS == AddLHS || ICmpLHS == AddRHS))
1668 return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
1669
1670 // Match special-case for increment-by-1.
1671 if (Pred == ICmpInst::ICMP_EQ) {
1672 // (a + 1) == 0
1673 // (1 + a) == 0
1674 if (AddExpr.match(ICmpLHS) && m_ZeroInt().match(ICmpRHS) &&
1675 (m_One().match(AddLHS) || m_One().match(AddRHS)))
1676 return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
1677 // 0 == (a + 1)
1678 // 0 == (1 + a)
1679 if (m_ZeroInt().match(ICmpLHS) && AddExpr.match(ICmpRHS) &&
1680 (m_One().match(AddLHS) || m_One().match(AddRHS)))
1681 return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
1682 }
1683
1684 return false;
1685 }
1686};
1687
1688/// Match an icmp instruction checking for unsigned overflow on addition.
1689///
1690/// S is matched to the addition whose result is being checked for overflow, and
1691/// L and R are matched to the LHS and RHS of S.
1692template <typename LHS_t, typename RHS_t, typename Sum_t>
1693UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>
1694m_UAddWithOverflow(const LHS_t &L, const RHS_t &R, const Sum_t &S) {
1695 return UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>(L, R, S);
1696}
1697
1698template <typename Opnd_t> struct Argument_match {
1699 unsigned OpI;
1700 Opnd_t Val;
1701
1702 Argument_match(unsigned OpIdx, const Opnd_t &V) : OpI(OpIdx), Val(V) {}
1703
1704 template <typename OpTy> bool match(OpTy *V) {
1705 // FIXME: Should likely be switched to use `CallBase`.
1706 if (const auto *CI = dyn_cast<CallInst>(V))
1707 return Val.match(CI->getArgOperand(OpI));
1708 return false;
1709 }
1710};
1711
1712/// Match an argument.
1713template <unsigned OpI, typename Opnd_t>
1714inline Argument_match<Opnd_t> m_Argument(const Opnd_t &Op) {
1715 return Argument_match<Opnd_t>(OpI, Op);
1716}
1717
1718/// Intrinsic matchers.
1719struct IntrinsicID_match {
1720 unsigned ID;
1721
1722 IntrinsicID_match(Intrinsic::ID IntrID) : ID(IntrID) {}
1723
1724 template <typename OpTy> bool match(OpTy *V) {
1725 if (const auto *CI
34.1
'CI' is null
43.1
'CI' is null
34.1
'CI' is null
43.1
'CI' is null
34.1
'CI' is null
43.1
'CI' is null
34.1
'CI' is null
43.1
'CI' is null
= dyn_cast<CallInst>(V))
34
Assuming 'V' is not a 'CallInst'
35
Taking false branch
43
'V' is not a 'CallInst'
44
Taking false branch
1726 if (const auto *F = CI->getCalledFunction())
1727 return F->getIntrinsicID() == ID;
1728 return false;
36
Returning zero, which participates in a condition later
45
Returning zero, which participates in a condition later
1729 }
1730};
1731
1732/// Intrinsic matches are combinations of ID matchers, and argument
1733/// matchers. Higher arity matcher are defined recursively in terms of and-ing
1734/// them with lower arity matchers. Here's some convenient typedefs for up to
1735/// several arguments, and more can be added as needed
1736template <typename T0 = void, typename T1 = void, typename T2 = void,
1737 typename T3 = void, typename T4 = void, typename T5 = void,
1738 typename T6 = void, typename T7 = void, typename T8 = void,
1739 typename T9 = void, typename T10 = void>
1740struct m_Intrinsic_Ty;
1741template <typename T0> struct m_Intrinsic_Ty<T0> {
1742 using Ty = match_combine_and<IntrinsicID_match, Argument_match<T0>>;
1743};
1744template <typename T0, typename T1> struct m_Intrinsic_Ty<T0, T1> {
1745 using Ty =
1746 match_combine_and<typename m_Intrinsic_Ty<T0>::Ty, Argument_match<T1>>;
1747};
1748template <typename T0, typename T1, typename T2>
1749struct m_Intrinsic_Ty<T0, T1, T2> {
1750 using Ty =
1751 match_combine_and<typename m_Intrinsic_Ty<T0, T1>::Ty,
1752 Argument_match<T2>>;
1753};
1754template <typename T0, typename T1, typename T2, typename T3>
1755struct m_Intrinsic_Ty<T0, T1, T2, T3> {
1756 using Ty =
1757 match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2>::Ty,
1758 Argument_match<T3>>;
1759};
1760
1761template <typename T0, typename T1, typename T2, typename T3, typename T4>
1762struct m_Intrinsic_Ty<T0, T1, T2, T3, T4> {
1763 using Ty = match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2, T3>::Ty,
1764 Argument_match<T4>>;
1765};
1766
1767/// Match intrinsic calls like this:
1768/// m_Intrinsic<Intrinsic::fabs>(m_Value(X))
1769template <Intrinsic::ID IntrID> inline IntrinsicID_match m_Intrinsic() {
1770 return IntrinsicID_match(IntrID);
1771}
1772
1773template <Intrinsic::ID IntrID, typename T0>
1774inline typename m_Intrinsic_Ty<T0>::Ty m_Intrinsic(const T0 &Op0) {
1775 return m_CombineAnd(m_Intrinsic<IntrID>(), m_Argument<0>(Op0));
1776}
1777
1778template <Intrinsic::ID IntrID, typename T0, typename T1>
1779inline typename m_Intrinsic_Ty<T0, T1>::Ty m_Intrinsic(const T0 &Op0,
1780 const T1 &Op1) {
1781 return m_CombineAnd(m_Intrinsic<IntrID>(Op0), m_Argument<1>(Op1));
1782}
1783
1784template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2>
1785inline typename m_Intrinsic_Ty<T0, T1, T2>::Ty
1786m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2) {
1787 return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1), m_Argument<2>(Op2));
1788}
1789
1790template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
1791 typename T3>
1792inline typename m_Intrinsic_Ty<T0, T1, T2, T3>::Ty
1793m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3) {
1794 return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2), m_Argument<3>(Op3));
1795}
1796
1797template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
1798 typename T3, typename T4>
1799inline typename m_Intrinsic_Ty<T0, T1, T2, T3, T4>::Ty
1800m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3,
1801 const T4 &Op4) {
1802 return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2, Op3),
1803 m_Argument<4>(Op4));
1804}
1805
1806// Helper intrinsic matching specializations.
1807template <typename Opnd0>
1808inline typename m_Intrinsic_Ty<Opnd0>::Ty m_BitReverse(const Opnd0 &Op0) {
1809 return m_Intrinsic<Intrinsic::bitreverse>(Op0);
1810}
1811
1812template <typename Opnd0>
1813inline typename m_Intrinsic_Ty<Opnd0>::Ty m_BSwap(const Opnd0 &Op0) {
1814 return m_Intrinsic<Intrinsic::bswap>(Op0);
1815}
1816
1817template <typename Opnd0>
1818inline typename m_Intrinsic_Ty<Opnd0>::Ty m_FAbs(const Opnd0 &Op0) {
1819 return m_Intrinsic<Intrinsic::fabs>(Op0);
1820}
1821
1822template <typename Opnd0>
1823inline typename m_Intrinsic_Ty<Opnd0>::Ty m_FCanonicalize(const Opnd0 &Op0) {
1824 return m_Intrinsic<Intrinsic::canonicalize>(Op0);
1825}
1826
1827template <typename Opnd0, typename Opnd1>
1828inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMin(const Opnd0 &Op0,
1829 const Opnd1 &Op1) {
1830 return m_Intrinsic<Intrinsic::minnum>(Op0, Op1);
1831}
1832
1833template <typename Opnd0, typename Opnd1>
1834inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMax(const Opnd0 &Op0,
1835 const Opnd1 &Op1) {
1836 return m_Intrinsic<Intrinsic::maxnum>(Op0, Op1);
1837}
1838
1839//===----------------------------------------------------------------------===//
1840// Matchers for two-operands operators with the operators in either order
1841//
1842
1843/// Matches a BinaryOperator with LHS and RHS in either order.
1844template <typename LHS, typename RHS>
1845inline AnyBinaryOp_match<LHS, RHS, true> m_c_BinOp(const LHS &L, const RHS &R) {
1846 return AnyBinaryOp_match<LHS, RHS, true>(L, R);
1847}
1848
1849/// Matches an ICmp with a predicate over LHS and RHS in either order.
1850/// Does not swap the predicate.
1851template <typename LHS, typename RHS>
1852inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate, true>
1853m_c_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1854 return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate, true>(Pred, L,
1855 R);
1856}
1857
1858/// Matches a Add with LHS and RHS in either order.
1859template <typename LHS, typename RHS>
1860inline BinaryOp_match<LHS, RHS, Instruction::Add, true> m_c_Add(const LHS &L,
1861 const RHS &R) {
1862 return BinaryOp_match<LHS, RHS, Instruction::Add, true>(L, R);
1863}
1864
1865/// Matches a Mul with LHS and RHS in either order.
1866template <typename LHS, typename RHS>
1867inline BinaryOp_match<LHS, RHS, Instruction::Mul, true> m_c_Mul(const LHS &L,
1868 const RHS &R) {
1869 return BinaryOp_match<LHS, RHS, Instruction::Mul, true>(L, R);
1870}
1871
1872/// Matches an And with LHS and RHS in either order.
1873template <typename LHS, typename RHS>
1874inline BinaryOp_match<LHS, RHS, Instruction::And, true> m_c_And(const LHS &L,
1875 const RHS &R) {
1876 return BinaryOp_match<LHS, RHS, Instruction::And, true>(L, R);
1877}
1878
1879/// Matches an Or with LHS and RHS in either order.
1880template <typename LHS, typename RHS>
1881inline BinaryOp_match<LHS, RHS, Instruction::Or, true> m_c_Or(const LHS &L,
1882 const RHS &R) {
1883 return BinaryOp_match<LHS, RHS, Instruction::Or, true>(L, R);
1884}
1885
1886/// Matches an Xor with LHS and RHS in either order.
1887template <typename LHS, typename RHS>
1888inline BinaryOp_match<LHS, RHS, Instruction::Xor, true> m_c_Xor(const LHS &L,
1889 const RHS &R) {
1890 return BinaryOp_match<LHS, RHS, Instruction::Xor, true>(L, R);
1891}
1892
1893/// Matches a 'Neg' as 'sub 0, V'.
1894template <typename ValTy>
1895inline BinaryOp_match<cst_pred_ty<is_zero_int>, ValTy, Instruction::Sub>
1896m_Neg(const ValTy &V) {
1897 return m_Sub(m_ZeroInt(), V);
1898}
1899
1900/// Matches a 'Not' as 'xor V, -1' or 'xor -1, V'.
1901template <typename ValTy>
1902inline BinaryOp_match<ValTy, cst_pred_ty<is_all_ones>, Instruction::Xor, true>
1903m_Not(const ValTy &V) {
1904 return m_c_Xor(V, m_AllOnes());
1905}
1906
1907/// Matches an SMin with LHS and RHS in either order.
1908template <typename LHS, typename RHS>
1909inline MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty, true>
1910m_c_SMin(const LHS &L, const RHS &R) {
1911 return MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty, true>(L, R);
1912}
1913/// Matches an SMax with LHS and RHS in either order.
1914template <typename LHS, typename RHS>
1915inline MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty, true>
1916m_c_SMax(const LHS &L, const RHS &R) {
1917 return MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty, true>(L, R);
1918}
1919/// Matches a UMin with LHS and RHS in either order.
1920template <typename LHS, typename RHS>
1921inline MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty, true>
1922m_c_UMin(const LHS &L, const RHS &R) {
1923 return MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty, true>(L, R);
1924}
1925/// Matches a UMax with LHS and RHS in either order.
1926template <typename LHS, typename RHS>
1927inline MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty, true>
1928m_c_UMax(const LHS &L, const RHS &R) {
1929 return MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty, true>(L, R);
1930}
1931
1932/// Matches FAdd with LHS and RHS in either order.
1933template <typename LHS, typename RHS>
1934inline BinaryOp_match<LHS, RHS, Instruction::FAdd, true>
1935m_c_FAdd(const LHS &L, const RHS &R) {
1936 return BinaryOp_match<LHS, RHS, Instruction::FAdd, true>(L, R);
1937}
1938
1939/// Matches FMul with LHS and RHS in either order.
1940template <typename LHS, typename RHS>
1941inline BinaryOp_match<LHS, RHS, Instruction::FMul, true>
1942m_c_FMul(const LHS &L, const RHS &R) {
1943 return BinaryOp_match<LHS, RHS, Instruction::FMul, true>(L, R);
1944}
1945
1946template <typename Opnd_t> struct Signum_match {
1947 Opnd_t Val;
1948 Signum_match(const Opnd_t &V) : Val(V) {}
1949
1950 template <typename OpTy> bool match(OpTy *V) {
1951 unsigned TypeSize = V->getType()->getScalarSizeInBits();
1952 if (TypeSize == 0)
1953 return false;
1954
1955 unsigned ShiftWidth = TypeSize - 1;
1956 Value *OpL = nullptr, *OpR = nullptr;
1957
1958 // This is the representation of signum we match:
1959 //
1960 // signum(x) == (x >> 63) | (-x >>u 63)
1961 //
1962 // An i1 value is its own signum, so it's correct to match
1963 //
1964 // signum(x) == (x >> 0) | (-x >>u 0)
1965 //
1966 // for i1 values.
1967
1968 auto LHS = m_AShr(m_Value(OpL), m_SpecificInt(ShiftWidth));
1969 auto RHS = m_LShr(m_Neg(m_Value(OpR)), m_SpecificInt(ShiftWidth));
1970 auto Signum = m_Or(LHS, RHS);
1971
1972 return Signum.match(V) && OpL == OpR && Val.match(OpL);
1973 }
1974};
1975
1976/// Matches a signum pattern.
1977///
1978/// signum(x) =
1979/// x > 0 -> 1
1980/// x == 0 -> 0
1981/// x < 0 -> -1
1982template <typename Val_t> inline Signum_match<Val_t> m_Signum(const Val_t &V) {
1983 return Signum_match<Val_t>(V);
1984}
1985
1986template <int Ind, typename Opnd_t> struct ExtractValue_match {
1987 Opnd_t Val;
1988 ExtractValue_match(const Opnd_t &V) : Val(V) {}
1989
1990 template <typename OpTy> bool match(OpTy *V) {
1991 if (auto *I = dyn_cast<ExtractValueInst>(V))
1992 return I->getNumIndices() == 1 && I->getIndices()[0] == Ind &&
1993 Val.match(I->getAggregateOperand());
1994 return false;
1995 }
1996};
1997
1998/// Match a single index ExtractValue instruction.
1999/// For example m_ExtractValue<1>(...)
2000template <int Ind, typename Val_t>
2001inline ExtractValue_match<Ind, Val_t> m_ExtractValue(const Val_t &V) {
2002 return ExtractValue_match<Ind, Val_t>(V);
2003}
2004
2005} // end namespace PatternMatch
2006} // end namespace llvm
2007
2008#endif // LLVM_IR_PATTERNMATCH_H

/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/include/llvm/Analysis/AliasAnalysis.h

1//===- llvm/Analysis/AliasAnalysis.h - Alias Analysis Interface -*- 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 defines the generic AliasAnalysis interface, which is used as the
10// common interface used by all clients of alias analysis information, and
11// implemented by all alias analysis implementations. Mod/Ref information is
12// also captured by this interface.
13//
14// Implementations of this interface must implement the various virtual methods,
15// which automatically provides functionality for the entire suite of client
16// APIs.
17//
18// This API identifies memory regions with the MemoryLocation class. The pointer
19// component specifies the base memory address of the region. The Size specifies
20// the maximum size (in address units) of the memory region, or
21// MemoryLocation::UnknownSize if the size is not known. The TBAA tag
22// identifies the "type" of the memory reference; see the
23// TypeBasedAliasAnalysis class for details.
24//
25// Some non-obvious details include:
26// - Pointers that point to two completely different objects in memory never
27// alias, regardless of the value of the Size component.
28// - NoAlias doesn't imply inequal pointers. The most obvious example of this
29// is two pointers to constant memory. Even if they are equal, constant
30// memory is never stored to, so there will never be any dependencies.
31// In this and other situations, the pointers may be both NoAlias and
32// MustAlias at the same time. The current API can only return one result,
33// though this is rarely a problem in practice.
34//
35//===----------------------------------------------------------------------===//
36
37#ifndef LLVM_ANALYSIS_ALIASANALYSIS_H
38#define LLVM_ANALYSIS_ALIASANALYSIS_H
39
40#include "llvm/ADT/DenseMap.h"
41#include "llvm/ADT/None.h"
42#include "llvm/ADT/Optional.h"
43#include "llvm/ADT/SmallVector.h"
44#include "llvm/Analysis/MemoryLocation.h"
45#include "llvm/Analysis/TargetLibraryInfo.h"
46#include "llvm/IR/Function.h"
47#include "llvm/IR/Instruction.h"
48#include "llvm/IR/Instructions.h"
49#include "llvm/IR/PassManager.h"
50#include "llvm/Pass.h"
51#include <cstdint>
52#include <functional>
53#include <memory>
54#include <vector>
55
56namespace llvm {
57
58class AnalysisUsage;
59class BasicAAResult;
60class BasicBlock;
61class DominatorTree;
62class OrderedBasicBlock;
63class Value;
64
65/// The possible results of an alias query.
66///
67/// These results are always computed between two MemoryLocation objects as
68/// a query to some alias analysis.
69///
70/// Note that these are unscoped enumerations because we would like to support
71/// implicitly testing a result for the existence of any possible aliasing with
72/// a conversion to bool, but an "enum class" doesn't support this. The
73/// canonical names from the literature are suffixed and unique anyways, and so
74/// they serve as global constants in LLVM for these results.
75///
76/// See docs/AliasAnalysis.html for more information on the specific meanings
77/// of these values.
78enum AliasResult : uint8_t {
79 /// The two locations do not alias at all.
80 ///
81 /// This value is arranged to convert to false, while all other values
82 /// convert to true. This allows a boolean context to convert the result to
83 /// a binary flag indicating whether there is the possibility of aliasing.
84 NoAlias = 0,
85 /// The two locations may or may not alias. This is the least precise result.
86 MayAlias,
87 /// The two locations alias, but only due to a partial overlap.
88 PartialAlias,
89 /// The two locations precisely alias each other.
90 MustAlias,
91};
92
93/// << operator for AliasResult.
94raw_ostream &operator<<(raw_ostream &OS, AliasResult AR);
95
96/// Flags indicating whether a memory access modifies or references memory.
97///
98/// This is no access at all, a modification, a reference, or both
99/// a modification and a reference. These are specifically structured such that
100/// they form a three bit matrix and bit-tests for 'mod' or 'ref' or 'must'
101/// work with any of the possible values.
102enum class ModRefInfo : uint8_t {
103 /// Must is provided for completeness, but no routines will return only
104 /// Must today. See definition of Must below.
105 Must = 0,
106 /// The access may reference the value stored in memory,
107 /// a mustAlias relation was found, and no mayAlias or partialAlias found.
108 MustRef = 1,
109 /// The access may modify the value stored in memory,
110 /// a mustAlias relation was found, and no mayAlias or partialAlias found.
111 MustMod = 2,
112 /// The access may reference, modify or both the value stored in memory,
113 /// a mustAlias relation was found, and no mayAlias or partialAlias found.
114 MustModRef = MustRef | MustMod,
115 /// The access neither references nor modifies the value stored in memory.
116 NoModRef = 4,
117 /// The access may reference the value stored in memory.
118 Ref = NoModRef | MustRef,
119 /// The access may modify the value stored in memory.
120 Mod = NoModRef | MustMod,
121 /// The access may reference and may modify the value stored in memory.
122 ModRef = Ref | Mod,
123
124 /// About Must:
125 /// Must is set in a best effort manner.
126 /// We usually do not try our best to infer Must, instead it is merely
127 /// another piece of "free" information that is presented when available.
128 /// Must set means there was certainly a MustAlias found. For calls,
129 /// where multiple arguments are checked (argmemonly), this translates to
130 /// only MustAlias or NoAlias was found.
131 /// Must is not set for RAR accesses, even if the two locations must
132 /// alias. The reason is that two read accesses translate to an early return
133 /// of NoModRef. An additional alias check to set Must may be
134 /// expensive. Other cases may also not set Must(e.g. callCapturesBefore).
135 /// We refer to Must being *set* when the most significant bit is *cleared*.
136 /// Conversely we *clear* Must information by *setting* the Must bit to 1.
137};
138
139LLVM_NODISCARD[[clang::warn_unused_result]] inline bool isNoModRef(const ModRefInfo MRI) {
140 return (static_cast<int>(MRI) & static_cast<int>(ModRefInfo::MustModRef)) ==
141 static_cast<int>(ModRefInfo::Must);
142}
143LLVM_NODISCARD[[clang::warn_unused_result]] inline bool isModOrRefSet(const ModRefInfo MRI) {
144 return static_cast<int>(MRI) & static_cast<int>(ModRefInfo::MustModRef);
145}
146LLVM_NODISCARD[[clang::warn_unused_result]] inline bool isModAndRefSet(const ModRefInfo MRI) {
147 return (static_cast<int>(MRI) & static_cast<int>(ModRefInfo::MustModRef)) ==
148 static_cast<int>(ModRefInfo::MustModRef);
149}
150LLVM_NODISCARD[[clang::warn_unused_result]] inline bool isModSet(const ModRefInfo MRI) {
151 return static_cast<int>(MRI) & static_cast<int>(ModRefInfo::MustMod);
152}
153LLVM_NODISCARD[[clang::warn_unused_result]] inline bool isRefSet(const ModRefInfo MRI) {
154 return static_cast<int>(MRI) & static_cast<int>(ModRefInfo::MustRef);
155}
156LLVM_NODISCARD[[clang::warn_unused_result]] inline bool isMustSet(const ModRefInfo MRI) {
157 return !(static_cast<int>(MRI) & static_cast<int>(ModRefInfo::NoModRef));
158}
159
160LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo setMod(const ModRefInfo MRI) {
161 return ModRefInfo(static_cast<int>(MRI) |
162 static_cast<int>(ModRefInfo::MustMod));
163}
164LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo setRef(const ModRefInfo MRI) {
165 return ModRefInfo(static_cast<int>(MRI) |
166 static_cast<int>(ModRefInfo::MustRef));
167}
168LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo setMust(const ModRefInfo MRI) {
169 return ModRefInfo(static_cast<int>(MRI) &
170 static_cast<int>(ModRefInfo::MustModRef));
171}
172LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo setModAndRef(const ModRefInfo MRI) {
173 return ModRefInfo(static_cast<int>(MRI) |
174 static_cast<int>(ModRefInfo::MustModRef));
175}
176LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo clearMod(const ModRefInfo MRI) {
177 return ModRefInfo(static_cast<int>(MRI) & static_cast<int>(ModRefInfo::Ref));
178}
179LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo clearRef(const ModRefInfo MRI) {
180 return ModRefInfo(static_cast<int>(MRI) & static_cast<int>(ModRefInfo::Mod));
181}
182LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo clearMust(const ModRefInfo MRI) {
183 return ModRefInfo(static_cast<int>(MRI) |
184 static_cast<int>(ModRefInfo::NoModRef));
185}
186LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo unionModRef(const ModRefInfo MRI1,
187 const ModRefInfo MRI2) {
188 return ModRefInfo(static_cast<int>(MRI1) | static_cast<int>(MRI2));
189}
190LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo intersectModRef(const ModRefInfo MRI1,
191 const ModRefInfo MRI2) {
192 return ModRefInfo(static_cast<int>(MRI1) & static_cast<int>(MRI2));
193}
194
195/// The locations at which a function might access memory.
196///
197/// These are primarily used in conjunction with the \c AccessKind bits to
198/// describe both the nature of access and the locations of access for a
199/// function call.
200enum FunctionModRefLocation {
201 /// Base case is no access to memory.
202 FMRL_Nowhere = 0,
203 /// Access to memory via argument pointers.
204 FMRL_ArgumentPointees = 8,
205 /// Memory that is inaccessible via LLVM IR.
206 FMRL_InaccessibleMem = 16,
207 /// Access to any memory.
208 FMRL_Anywhere = 32 | FMRL_InaccessibleMem | FMRL_ArgumentPointees
209};
210
211/// Summary of how a function affects memory in the program.
212///
213/// Loads from constant globals are not considered memory accesses for this
214/// interface. Also, functions may freely modify stack space local to their
215/// invocation without having to report it through these interfaces.
216enum FunctionModRefBehavior {
217 /// This function does not perform any non-local loads or stores to memory.
218 ///
219 /// This property corresponds to the GCC 'const' attribute.
220 /// This property corresponds to the LLVM IR 'readnone' attribute.
221 /// This property corresponds to the IntrNoMem LLVM intrinsic flag.
222 FMRB_DoesNotAccessMemory =
223 FMRL_Nowhere | static_cast<int>(ModRefInfo::NoModRef),
224
225 /// The only memory references in this function (if it has any) are
226 /// non-volatile loads from objects pointed to by its pointer-typed
227 /// arguments, with arbitrary offsets.
228 ///
229 /// This property corresponds to the IntrReadArgMem LLVM intrinsic flag.
230 FMRB_OnlyReadsArgumentPointees =
231 FMRL_ArgumentPointees | static_cast<int>(ModRefInfo::Ref),
232
233 /// The only memory references in this function (if it has any) are
234 /// non-volatile loads and stores from objects pointed to by its
235 /// pointer-typed arguments, with arbitrary offsets.
236 ///
237 /// This property corresponds to the IntrArgMemOnly LLVM intrinsic flag.
238 FMRB_OnlyAccessesArgumentPointees =
239 FMRL_ArgumentPointees | static_cast<int>(ModRefInfo::ModRef),
240
241 /// The only memory references in this function (if it has any) are
242 /// references of memory that is otherwise inaccessible via LLVM IR.
243 ///
244 /// This property corresponds to the LLVM IR inaccessiblememonly attribute.
245 FMRB_OnlyAccessesInaccessibleMem =
246 FMRL_InaccessibleMem | static_cast<int>(ModRefInfo::ModRef),
247
248 /// The function may perform non-volatile loads and stores of objects
249 /// pointed to by its pointer-typed arguments, with arbitrary offsets, and
250 /// it may also perform loads and stores of memory that is otherwise
251 /// inaccessible via LLVM IR.
252 ///
253 /// This property corresponds to the LLVM IR
254 /// inaccessiblemem_or_argmemonly attribute.
255 FMRB_OnlyAccessesInaccessibleOrArgMem = FMRL_InaccessibleMem |
256 FMRL_ArgumentPointees |
257 static_cast<int>(ModRefInfo::ModRef),
258
259 /// This function does not perform any non-local stores or volatile loads,
260 /// but may read from any memory location.
261 ///
262 /// This property corresponds to the GCC 'pure' attribute.
263 /// This property corresponds to the LLVM IR 'readonly' attribute.
264 /// This property corresponds to the IntrReadMem LLVM intrinsic flag.
265 FMRB_OnlyReadsMemory = FMRL_Anywhere | static_cast<int>(ModRefInfo::Ref),
266
267 // This function does not read from memory anywhere, but may write to any
268 // memory location.
269 //
270 // This property corresponds to the LLVM IR 'writeonly' attribute.
271 // This property corresponds to the IntrWriteMem LLVM intrinsic flag.
272 FMRB_DoesNotReadMemory = FMRL_Anywhere | static_cast<int>(ModRefInfo::Mod),
273
274 /// This indicates that the function could not be classified into one of the
275 /// behaviors above.
276 FMRB_UnknownModRefBehavior =
277 FMRL_Anywhere | static_cast<int>(ModRefInfo::ModRef)
278};
279
280// Wrapper method strips bits significant only in FunctionModRefBehavior,
281// to obtain a valid ModRefInfo. The benefit of using the wrapper is that if
282// ModRefInfo enum changes, the wrapper can be updated to & with the new enum
283// entry with all bits set to 1.
284LLVM_NODISCARD[[clang::warn_unused_result]] inline ModRefInfo
285createModRefInfo(const FunctionModRefBehavior FMRB) {
286 return ModRefInfo(FMRB & static_cast<int>(ModRefInfo::ModRef));
287}
288
289/// This class stores info we want to provide to or retain within an alias
290/// query. By default, the root query is stateless and starts with a freshly
291/// constructed info object. Specific alias analyses can use this query info to
292/// store per-query state that is important for recursive or nested queries to
293/// avoid recomputing. To enable preserving this state across multiple queries
294/// where safe (due to the IR not changing), use a `BatchAAResults` wrapper.
295/// The information stored in an `AAQueryInfo` is currently limitted to the
296/// caches used by BasicAA, but can further be extended to fit other AA needs.
297class AAQueryInfo {
298public:
299 using LocPair = std::pair<MemoryLocation, MemoryLocation>;
300 using AliasCacheT = SmallDenseMap<LocPair, AliasResult, 8>;
301 AliasCacheT AliasCache;
302
303 using IsCapturedCacheT = SmallDenseMap<const Value *, bool, 8>;
304 IsCapturedCacheT IsCapturedCache;
305
306 AAQueryInfo() : AliasCache(), IsCapturedCache() {}
307};
308
309class BatchAAResults;
310
311class AAResults {
312public:
313 // Make these results default constructable and movable. We have to spell
314 // these out because MSVC won't synthesize them.
315 AAResults(const TargetLibraryInfo &TLI) : TLI(TLI) {}
316 AAResults(AAResults &&Arg);
317 ~AAResults();
318
319 /// Register a specific AA result.
320 template <typename AAResultT> void addAAResult(AAResultT &AAResult) {
321 // FIXME: We should use a much lighter weight system than the usual
322 // polymorphic pattern because we don't own AAResult. It should
323 // ideally involve two pointers and no separate allocation.
324 AAs.emplace_back(new Model<AAResultT>(AAResult, *this));
325 }
326
327 /// Register a function analysis ID that the results aggregation depends on.
328 ///
329 /// This is used in the new pass manager to implement the invalidation logic
330 /// where we must invalidate the results aggregation if any of our component
331 /// analyses become invalid.
332 void addAADependencyID(AnalysisKey *ID) { AADeps.push_back(ID); }
333
334 /// Handle invalidation events in the new pass manager.
335 ///
336 /// The aggregation is invalidated if any of the underlying analyses is
337 /// invalidated.
338 bool invalidate(Function &F, const PreservedAnalyses &PA,
339 FunctionAnalysisManager::Invalidator &Inv);
340
341 //===--------------------------------------------------------------------===//
342 /// \name Alias Queries
343 /// @{
344
345 /// The main low level interface to the alias analysis implementation.
346 /// Returns an AliasResult indicating whether the two pointers are aliased to
347 /// each other. This is the interface that must be implemented by specific
348 /// alias analysis implementations.
349 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB);
350
351 /// A convenience wrapper around the primary \c alias interface.
352 AliasResult alias(const Value *V1, LocationSize V1Size, const Value *V2,
353 LocationSize V2Size) {
354 return alias(MemoryLocation(V1, V1Size), MemoryLocation(V2, V2Size));
355 }
356
357 /// A convenience wrapper around the primary \c alias interface.
358 AliasResult alias(const Value *V1, const Value *V2) {
359 return alias(V1, LocationSize::unknown(), V2, LocationSize::unknown());
360 }
361
362 /// A trivial helper function to check to see if the specified pointers are
363 /// no-alias.
364 bool isNoAlias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
365 return alias(LocA, LocB) == NoAlias;
366 }
367
368 /// A convenience wrapper around the \c isNoAlias helper interface.
369 bool isNoAlias(const Value *V1, LocationSize V1Size, const Value *V2,
370 LocationSize V2Size) {
371 return isNoAlias(MemoryLocation(V1, V1Size), MemoryLocation(V2, V2Size));
372 }
373
374 /// A convenience wrapper around the \c isNoAlias helper interface.
375 bool isNoAlias(const Value *V1, const Value *V2) {
376 return isNoAlias(MemoryLocation(V1), MemoryLocation(V2));
377 }
378
379 /// A trivial helper function to check to see if the specified pointers are
380 /// must-alias.
381 bool isMustAlias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
382 return alias(LocA, LocB) == MustAlias;
383 }
384
385 /// A convenience wrapper around the \c isMustAlias helper interface.
386 bool isMustAlias(const Value *V1, const Value *V2) {
387 return alias(V1, LocationSize::precise(1), V2, LocationSize::precise(1)) ==
388 MustAlias;
389 }
390
391 /// Checks whether the given location points to constant memory, or if
392 /// \p OrLocal is true whether it points to a local alloca.
393 bool pointsToConstantMemory(const MemoryLocation &Loc, bool OrLocal = false);
394
395 /// A convenience wrapper around the primary \c pointsToConstantMemory
396 /// interface.
397 bool pointsToConstantMemory(const Value *P, bool OrLocal = false) {
398 return pointsToConstantMemory(MemoryLocation(P), OrLocal);
399 }
400
401 /// @}
402 //===--------------------------------------------------------------------===//
403 /// \name Simple mod/ref information
404 /// @{
405
406 /// Get the ModRef info associated with a pointer argument of a call. The
407 /// result's bits are set to indicate the allowed aliasing ModRef kinds. Note
408 /// that these bits do not necessarily account for the overall behavior of
409 /// the function, but rather only provide additional per-argument
410 /// information. This never sets ModRefInfo::Must.
411 ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx);
412
413 /// Return the behavior of the given call site.
414 FunctionModRefBehavior getModRefBehavior(const CallBase *Call);
415
416 /// Return the behavior when calling the given function.
417 FunctionModRefBehavior getModRefBehavior(const Function *F);
418
419 /// Checks if the specified call is known to never read or write memory.
420 ///
421 /// Note that if the call only reads from known-constant memory, it is also
422 /// legal to return true. Also, calls that unwind the stack are legal for
423 /// this predicate.
424 ///
425 /// Many optimizations (such as CSE and LICM) can be performed on such calls
426 /// without worrying about aliasing properties, and many calls have this
427 /// property (e.g. calls to 'sin' and 'cos').
428 ///
429 /// This property corresponds to the GCC 'const' attribute.
430 bool doesNotAccessMemory(const CallBase *Call) {
431 return getModRefBehavior(Call) == FMRB_DoesNotAccessMemory;
432 }
433
434 /// Checks if the specified function is known to never read or write memory.
435 ///
436 /// Note that if the function only reads from known-constant memory, it is
437 /// also legal to return true. Also, function that unwind the stack are legal
438 /// for this predicate.
439 ///
440 /// Many optimizations (such as CSE and LICM) can be performed on such calls
441 /// to such functions without worrying about aliasing properties, and many
442 /// functions have this property (e.g. 'sin' and 'cos').
443 ///
444 /// This property corresponds to the GCC 'const' attribute.
445 bool doesNotAccessMemory(const Function *F) {
446 return getModRefBehavior(F) == FMRB_DoesNotAccessMemory;
447 }
448
449 /// Checks if the specified call is known to only read from non-volatile
450 /// memory (or not access memory at all).
451 ///
452 /// Calls that unwind the stack are legal for this predicate.
453 ///
454 /// This property allows many common optimizations to be performed in the
455 /// absence of interfering store instructions, such as CSE of strlen calls.
456 ///
457 /// This property corresponds to the GCC 'pure' attribute.
458 bool onlyReadsMemory(const CallBase *Call) {
459 return onlyReadsMemory(getModRefBehavior(Call));
460 }
461
462 /// Checks if the specified function is known to only read from non-volatile
463 /// memory (or not access memory at all).
464 ///
465 /// Functions that unwind the stack are legal for this predicate.
466 ///
467 /// This property allows many common optimizations to be performed in the
468 /// absence of interfering store instructions, such as CSE of strlen calls.
469 ///
470 /// This property corresponds to the GCC 'pure' attribute.
471 bool onlyReadsMemory(const Function *F) {
472 return onlyReadsMemory(getModRefBehavior(F));
473 }
474
475 /// Checks if functions with the specified behavior are known to only read
476 /// from non-volatile memory (or not access memory at all).
477 static bool onlyReadsMemory(FunctionModRefBehavior MRB) {
478 return !isModSet(createModRefInfo(MRB));
53
Assuming the condition is true
54
Returning the value 1, which participates in a condition later
479 }
480
481 /// Checks if functions with the specified behavior are known to only write
482 /// memory (or not access memory at all).
483 static bool doesNotReadMemory(FunctionModRefBehavior MRB) {
484 return !isRefSet(createModRefInfo(MRB));
485 }
486
487 /// Checks if functions with the specified behavior are known to read and
488 /// write at most from objects pointed to by their pointer-typed arguments
489 /// (with arbitrary offsets).
490 static bool onlyAccessesArgPointees(FunctionModRefBehavior MRB) {
491 return !(MRB & FMRL_Anywhere & ~FMRL_ArgumentPointees);
58
Assuming the condition is true
59
Returning the value 1, which participates in a condition later
492 }
493
494 /// Checks if functions with the specified behavior are known to potentially
495 /// read or write from objects pointed to be their pointer-typed arguments
496 /// (with arbitrary offsets).
497 static bool doesAccessArgPointees(FunctionModRefBehavior MRB) {
498 return isModOrRefSet(createModRefInfo(MRB)) &&
499 (MRB & FMRL_ArgumentPointees);
500 }
501
502 /// Checks if functions with the specified behavior are known to read and
503 /// write at most from memory that is inaccessible from LLVM IR.
504 static bool onlyAccessesInaccessibleMem(FunctionModRefBehavior MRB) {
505 return !(MRB & FMRL_Anywhere & ~FMRL_InaccessibleMem);
506 }
507
508 /// Checks if functions with the specified behavior are known to potentially
509 /// read or write from memory that is inaccessible from LLVM IR.
510 static bool doesAccessInaccessibleMem(FunctionModRefBehavior MRB) {
511 return isModOrRefSet(createModRefInfo(MRB)) && (MRB & FMRL_InaccessibleMem);
512 }
513
514 /// Checks if functions with the specified behavior are known to read and
515 /// write at most from memory that is inaccessible from LLVM IR or objects
516 /// pointed to by their pointer-typed arguments (with arbitrary offsets).
517 static bool onlyAccessesInaccessibleOrArgMem(FunctionModRefBehavior MRB) {
518 return !(MRB & FMRL_Anywhere &
519 ~(FMRL_InaccessibleMem | FMRL_ArgumentPointees));
520 }
521
522 /// getModRefInfo (for call sites) - Return information about whether
523 /// a particular call site modifies or reads the specified memory location.
524 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc);
525
526 /// getModRefInfo (for call sites) - A convenience wrapper.
527 ModRefInfo getModRefInfo(const CallBase *Call, const Value *P,
528 LocationSize Size) {
529 return getModRefInfo(Call, MemoryLocation(P, Size));
530 }
531
532 /// getModRefInfo (for loads) - Return information about whether
533 /// a particular load modifies or reads the specified memory location.
534 ModRefInfo getModRefInfo(const LoadInst *L, const MemoryLocation &Loc);
535
536 /// getModRefInfo (for loads) - A convenience wrapper.
537 ModRefInfo getModRefInfo(const LoadInst *L, const Value *P,
538 LocationSize Size) {
539 return getModRefInfo(L, MemoryLocation(P, Size));
540 }
541
542 /// getModRefInfo (for stores) - Return information about whether
543 /// a particular store modifies or reads the specified memory location.
544 ModRefInfo getModRefInfo(const StoreInst *S, const MemoryLocation &Loc);
545
546 /// getModRefInfo (for stores) - A convenience wrapper.
547 ModRefInfo getModRefInfo(const StoreInst *S, const Value *P,
548 LocationSize Size) {
549 return getModRefInfo(S, MemoryLocation(P, Size));
550 }
551
552 /// getModRefInfo (for fences) - Return information about whether
553 /// a particular store modifies or reads the specified memory location.
554 ModRefInfo getModRefInfo(const FenceInst *S, const MemoryLocation &Loc);
555
556 /// getModRefInfo (for fences) - A convenience wrapper.
557 ModRefInfo getModRefInfo(const FenceInst *S, const Value *P,
558 LocationSize Size) {
559 return getModRefInfo(S, MemoryLocation(P, Size));
560 }
561
562 /// getModRefInfo (for cmpxchges) - Return information about whether
563 /// a particular cmpxchg modifies or reads the specified memory location.
564 ModRefInfo getModRefInfo(const AtomicCmpXchgInst *CX,
565 const MemoryLocation &Loc);
566
567 /// getModRefInfo (for cmpxchges) - A convenience wrapper.
568 ModRefInfo getModRefInfo(const AtomicCmpXchgInst *CX, const Value *P,
569 LocationSize Size) {
570 return getModRefInfo(CX, MemoryLocation(P, Size));
571 }
572
573 /// getModRefInfo (for atomicrmws) - Return information about whether
574 /// a particular atomicrmw modifies or reads the specified memory location.
575 ModRefInfo getModRefInfo(const AtomicRMWInst *RMW, const MemoryLocation &Loc);
576
577 /// getModRefInfo (for atomicrmws) - A convenience wrapper.
578 ModRefInfo getModRefInfo(const AtomicRMWInst *RMW, const Value *P,
579 LocationSize Size) {
580 return getModRefInfo(RMW, MemoryLocation(P, Size));
581 }
582
583 /// getModRefInfo (for va_args) - Return information about whether
584 /// a particular va_arg modifies or reads the specified memory location.
585 ModRefInfo getModRefInfo(const VAArgInst *I, const MemoryLocation &Loc);
586
587 /// getModRefInfo (for va_args) - A convenience wrapper.
588 ModRefInfo getModRefInfo(const VAArgInst *I, const Value *P,
589 LocationSize Size) {
590 return getModRefInfo(I, MemoryLocation(P, Size));
591 }
592
593 /// getModRefInfo (for catchpads) - Return information about whether
594 /// a particular catchpad modifies or reads the specified memory location.
595 ModRefInfo getModRefInfo(const CatchPadInst *I, const MemoryLocation &Loc);
596
597 /// getModRefInfo (for catchpads) - A convenience wrapper.
598 ModRefInfo getModRefInfo(const CatchPadInst *I, const Value *P,
599 LocationSize Size) {
600 return getModRefInfo(I, MemoryLocation(P, Size));
601 }
602
603 /// getModRefInfo (for catchrets) - Return information about whether
604 /// a particular catchret modifies or reads the specified memory location.
605 ModRefInfo getModRefInfo(const CatchReturnInst *I, const MemoryLocation &Loc);
606
607 /// getModRefInfo (for catchrets) - A convenience wrapper.
608 ModRefInfo getModRefInfo(const CatchReturnInst *I, const Value *P,
609 LocationSize Size) {
610 return getModRefInfo(I, MemoryLocation(P, Size));
611 }
612
613 /// Check whether or not an instruction may read or write the optionally
614 /// specified memory location.
615 ///
616 ///
617 /// An instruction that doesn't read or write memory may be trivially LICM'd
618 /// for example.
619 ///
620 /// For function calls, this delegates to the alias-analysis specific
621 /// call-site mod-ref behavior queries. Otherwise it delegates to the specific
622 /// helpers above.
623 ModRefInfo getModRefInfo(const Instruction *I,
624 const Optional<MemoryLocation> &OptLoc) {
625 AAQueryInfo AAQIP;
626 return getModRefInfo(I, OptLoc, AAQIP);
627 }
628
629 /// A convenience wrapper for constructing the memory location.
630 ModRefInfo getModRefInfo(const Instruction *I, const Value *P,
631 LocationSize Size) {
632 return getModRefInfo(I, MemoryLocation(P, Size));
633 }
634
635 /// Return information about whether a call and an instruction may refer to
636 /// the same memory locations.
637 ModRefInfo getModRefInfo(Instruction *I, const CallBase *Call);
638
639 /// Return information about whether two call sites may refer to the same set
640 /// of memory locations. See the AA documentation for details:
641 /// http://llvm.org/docs/AliasAnalysis.html#ModRefInfo
642 ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2);
643
644 /// Return information about whether a particular call site modifies
645 /// or reads the specified memory location \p MemLoc before instruction \p I
646 /// in a BasicBlock. An ordered basic block \p OBB can be used to speed up
647 /// instruction ordering queries inside the BasicBlock containing \p I.
648 /// Early exits in callCapturesBefore may lead to ModRefInfo::Must not being
649 /// set.
650 ModRefInfo callCapturesBefore(const Instruction *I,
651 const MemoryLocation &MemLoc, DominatorTree *DT,
652 OrderedBasicBlock *OBB = nullptr);
653
654 /// A convenience wrapper to synthesize a memory location.
655 ModRefInfo callCapturesBefore(const Instruction *I, const Value *P,
656 LocationSize Size, DominatorTree *DT,
657 OrderedBasicBlock *OBB = nullptr) {
658 return callCapturesBefore(I, MemoryLocation(P, Size), DT, OBB);
659 }
660
661 /// @}
662 //===--------------------------------------------------------------------===//
663 /// \name Higher level methods for querying mod/ref information.
664 /// @{
665
666 /// Check if it is possible for execution of the specified basic block to
667 /// modify the location Loc.
668 bool canBasicBlockModify(const BasicBlock &BB, const MemoryLocation &Loc);
669
670 /// A convenience wrapper synthesizing a memory location.
671 bool canBasicBlockModify(const BasicBlock &BB, const Value *P,
672 LocationSize Size) {
673 return canBasicBlockModify(BB, MemoryLocation(P, Size));
674 }
675
676 /// Check if it is possible for the execution of the specified instructions
677 /// to mod\ref (according to the mode) the location Loc.
678 ///
679 /// The instructions to consider are all of the instructions in the range of
680 /// [I1,I2] INCLUSIVE. I1 and I2 must be in the same basic block.
681 bool canInstructionRangeModRef(const Instruction &I1, const Instruction &I2,
682 const MemoryLocation &Loc,
683 const ModRefInfo Mode);
684
685 /// A convenience wrapper synthesizing a memory location.
686 bool canInstructionRangeModRef(const Instruction &I1, const Instruction &I2,
687 const Value *Ptr, LocationSize Size,
688 const ModRefInfo Mode) {
689 return canInstructionRangeModRef(I1, I2, MemoryLocation(Ptr, Size), Mode);
690 }
691
692private:
693 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
694 AAQueryInfo &AAQI);
695 bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
696 bool OrLocal = false);
697 ModRefInfo getModRefInfo(Instruction *I, const CallBase *Call2,
698 AAQueryInfo &AAQIP);
699 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
700 AAQueryInfo &AAQI);
701 ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2,
702 AAQueryInfo &AAQI);
703 ModRefInfo getModRefInfo(const VAArgInst *V, const MemoryLocation &Loc,
704 AAQueryInfo &AAQI);
705 ModRefInfo getModRefInfo(const LoadInst *L, const MemoryLocation &Loc,
706 AAQueryInfo &AAQI);
707 ModRefInfo getModRefInfo(const StoreInst *S, const MemoryLocation &Loc,
708 AAQueryInfo &AAQI);
709 ModRefInfo getModRefInfo(const FenceInst *S, const MemoryLocation &Loc,
710 AAQueryInfo &AAQI);
711 ModRefInfo getModRefInfo(const AtomicCmpXchgInst *CX,
712 const MemoryLocation &Loc, AAQueryInfo &AAQI);
713 ModRefInfo getModRefInfo(const AtomicRMWInst *RMW, const MemoryLocation &Loc,
714 AAQueryInfo &AAQI);
715 ModRefInfo getModRefInfo(const CatchPadInst *I, const MemoryLocation &Loc,
716 AAQueryInfo &AAQI);
717 ModRefInfo getModRefInfo(const CatchReturnInst *I, const MemoryLocation &Loc,
718 AAQueryInfo &AAQI);
719 ModRefInfo getModRefInfo(const Instruction *I,
720 const Optional<MemoryLocation> &OptLoc,
721 AAQueryInfo &AAQIP) {
722 if (OptLoc == None) {
723 if (const auto *Call = dyn_cast<CallBase>(I)) {
724 return createModRefInfo(getModRefBehavior(Call));
725 }
726 }
727
728 const MemoryLocation &Loc = OptLoc.getValueOr(MemoryLocation());
729
730 switch (I->getOpcode()) {
731 case Instruction::VAArg:
732 return getModRefInfo((const VAArgInst *)I, Loc, AAQIP);
733 case Instruction::Load:
734 return getModRefInfo((const LoadInst *)I, Loc, AAQIP);
735 case Instruction::Store:
736 return getModRefInfo((const StoreInst *)I, Loc, AAQIP);
737 case Instruction::Fence:
738 return getModRefInfo((const FenceInst *)I, Loc, AAQIP);
739 case Instruction::AtomicCmpXchg:
740 return getModRefInfo((const AtomicCmpXchgInst *)I, Loc, AAQIP);
741 case Instruction::AtomicRMW:
742 return getModRefInfo((const AtomicRMWInst *)I, Loc, AAQIP);
743 case Instruction::Call:
744 return getModRefInfo((const CallInst *)I, Loc, AAQIP);
745 case Instruction::Invoke:
746 return getModRefInfo((const InvokeInst *)I, Loc, AAQIP);
747 case Instruction::CatchPad:
748 return getModRefInfo((const CatchPadInst *)I, Loc, AAQIP);
749 case Instruction::CatchRet:
750 return getModRefInfo((const CatchReturnInst *)I, Loc, AAQIP);
751 default:
752 return ModRefInfo::NoModRef;
753 }
754 }
755
756 class Concept;
757
758 template <typename T> class Model;
759
760 template <typename T> friend class AAResultBase;
761
762 const TargetLibraryInfo &TLI;
763
764 std::vector<std::unique_ptr<Concept>> AAs;
765
766 std::vector<AnalysisKey *> AADeps;
767
768 friend class BatchAAResults;
769};
770
771/// This class is a wrapper over an AAResults, and it is intended to be used
772/// only when there are no IR changes inbetween queries. BatchAAResults is
773/// reusing the same `AAQueryInfo` to preserve the state across queries,
774/// esentially making AA work in "batch mode". The internal state cannot be
775/// cleared, so to go "out-of-batch-mode", the user must either use AAResults,
776/// or create a new BatchAAResults.
777class BatchAAResults {
778 AAResults &AA;
779 AAQueryInfo AAQI;
780
781public:
782 BatchAAResults(AAResults &AAR) : AA(AAR), AAQI() {}
783 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
784 return AA.alias(LocA, LocB, AAQI);
785 }
786 bool pointsToConstantMemory(const MemoryLocation &Loc, bool OrLocal = false) {
787 return AA.pointsToConstantMemory(Loc, AAQI, OrLocal);
788 }
789 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc) {
790 return AA.getModRefInfo(Call, Loc, AAQI);
791 }
792 ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2) {
793 return AA.getModRefInfo(Call1, Call2, AAQI);
794 }
795 ModRefInfo getModRefInfo(const Instruction *I,
796 const Optional<MemoryLocation> &OptLoc) {
797 return AA.getModRefInfo(I, OptLoc, AAQI);
798 }
799 ModRefInfo getModRefInfo(Instruction *I, const CallBase *Call2) {
800 return AA.getModRefInfo(I, Call2, AAQI);
801 }
802 ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) {
803 return AA.getArgModRefInfo(Call, ArgIdx);
804 }
805 FunctionModRefBehavior getModRefBehavior(const CallBase *Call) {
806 return AA.getModRefBehavior(Call);
807 }
808};
809
810/// Temporary typedef for legacy code that uses a generic \c AliasAnalysis
811/// pointer or reference.
812using AliasAnalysis = AAResults;
813
814/// A private abstract base class describing the concept of an individual alias
815/// analysis implementation.
816///
817/// This interface is implemented by any \c Model instantiation. It is also the
818/// interface which a type used to instantiate the model must provide.
819///
820/// All of these methods model methods by the same name in the \c
821/// AAResults class. Only differences and specifics to how the
822/// implementations are called are documented here.
823class AAResults::Concept {
824public:
825 virtual ~Concept() = 0;
826
827 /// An update API used internally by the AAResults to provide
828 /// a handle back to the top level aggregation.
829 virtual void setAAResults(AAResults *NewAAR) = 0;
830
831 //===--------------------------------------------------------------------===//
832 /// \name Alias Queries
833 /// @{
834
835 /// The main low level interface to the alias analysis implementation.
836 /// Returns an AliasResult indicating whether the two pointers are aliased to
837 /// each other. This is the interface that must be implemented by specific
838 /// alias analysis implementations.
839 virtual AliasResult alias(const MemoryLocation &LocA,
840 const MemoryLocation &LocB, AAQueryInfo &AAQI) = 0;
841
842 /// Checks whether the given location points to constant memory, or if
843 /// \p OrLocal is true whether it points to a local alloca.
844 virtual bool pointsToConstantMemory(const MemoryLocation &Loc,
845 AAQueryInfo &AAQI, bool OrLocal) = 0;
846
847 /// @}
848 //===--------------------------------------------------------------------===//
849 /// \name Simple mod/ref information
850 /// @{
851
852 /// Get the ModRef info associated with a pointer argument of a callsite. The
853 /// result's bits are set to indicate the allowed aliasing ModRef kinds. Note
854 /// that these bits do not necessarily account for the overall behavior of
855 /// the function, but rather only provide additional per-argument
856 /// information.
857 virtual ModRefInfo getArgModRefInfo(const CallBase *Call,
858 unsigned ArgIdx) = 0;
859
860 /// Return the behavior of the given call site.
861 virtual FunctionModRefBehavior getModRefBehavior(const CallBase *Call) = 0;
862
863 /// Return the behavior when calling the given function.
864 virtual FunctionModRefBehavior getModRefBehavior(const Function *F) = 0;
865
866 /// getModRefInfo (for call sites) - Return information about whether
867 /// a particular call site modifies or reads the specified memory location.
868 virtual ModRefInfo getModRefInfo(const CallBase *Call,
869 const MemoryLocation &Loc,
870 AAQueryInfo &AAQI) = 0;
871
872 /// Return information about whether two call sites may refer to the same set
873 /// of memory locations. See the AA documentation for details:
874 /// http://llvm.org/docs/AliasAnalysis.html#ModRefInfo
875 virtual ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2,
876 AAQueryInfo &AAQI) = 0;
877
878 /// @}
879};
880
881/// A private class template which derives from \c Concept and wraps some other
882/// type.
883///
884/// This models the concept by directly forwarding each interface point to the
885/// wrapped type which must implement a compatible interface. This provides
886/// a type erased binding.
887template <typename AAResultT> class AAResults::Model final : public Concept {
888 AAResultT &Result;
889
890public:
891 explicit Model(AAResultT &Result, AAResults &AAR) : Result(Result) {
892 Result.setAAResults(&AAR);
893 }
894 ~Model() override = default;
895
896 void setAAResults(AAResults *NewAAR) override { Result.setAAResults(NewAAR); }
897
898 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
899 AAQueryInfo &AAQI) override {
900 return Result.alias(LocA, LocB, AAQI);
901 }
902
903 bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
904 bool OrLocal) override {
905 return Result.pointsToConstantMemory(Loc, AAQI, OrLocal);
906 }
907
908 ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) override {
909 return Result.getArgModRefInfo(Call, ArgIdx);
910 }
911
912 FunctionModRefBehavior getModRefBehavior(const CallBase *Call) override {
913 return Result.getModRefBehavior(Call);
914 }
915
916 FunctionModRefBehavior getModRefBehavior(const Function *F) override {
917 return Result.getModRefBehavior(F);
918 }
919
920 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
921 AAQueryInfo &AAQI) override {
922 return Result.getModRefInfo(Call, Loc, AAQI);
923 }
924
925 ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2,
926 AAQueryInfo &AAQI) override {
927 return Result.getModRefInfo(Call1, Call2, AAQI);
928 }
929};
930
931/// A CRTP-driven "mixin" base class to help implement the function alias
932/// analysis results concept.
933///
934/// Because of the nature of many alias analysis implementations, they often
935/// only implement a subset of the interface. This base class will attempt to
936/// implement the remaining portions of the interface in terms of simpler forms
937/// of the interface where possible, and otherwise provide conservatively
938/// correct fallback implementations.
939///
940/// Implementors of an alias analysis should derive from this CRTP, and then
941/// override specific methods that they wish to customize. There is no need to
942/// use virtual anywhere, the CRTP base class does static dispatch to the
943/// derived type passed into it.
944template <typename DerivedT> class AAResultBase {
945 // Expose some parts of the interface only to the AAResults::Model
946 // for wrapping. Specifically, this allows the model to call our
947 // setAAResults method without exposing it as a fully public API.
948 friend class AAResults::Model<DerivedT>;
949
950 /// A pointer to the AAResults object that this AAResult is
951 /// aggregated within. May be null if not aggregated.
952 AAResults *AAR = nullptr;
953
954 /// Helper to dispatch calls back through the derived type.
955 DerivedT &derived() { return static_cast<DerivedT &>(*this); }
956
957 /// A setter for the AAResults pointer, which is used to satisfy the
958 /// AAResults::Model contract.
959 void setAAResults(AAResults *NewAAR) { AAR = NewAAR; }
960
961protected:
962 /// This proxy class models a common pattern where we delegate to either the
963 /// top-level \c AAResults aggregation if one is registered, or to the
964 /// current result if none are registered.
965 class AAResultsProxy {
966 AAResults *AAR;
967 DerivedT &CurrentResult;
968
969 public:
970 AAResultsProxy(AAResults *AAR, DerivedT &CurrentResult)
971 : AAR(AAR), CurrentResult(CurrentResult) {}
972
973 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
974 AAQueryInfo &AAQI) {
975 return AAR ? AAR->alias(LocA, LocB, AAQI)
976 : CurrentResult.alias(LocA, LocB, AAQI);
977 }
978
979 bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
980 bool OrLocal) {
981 return AAR ? AAR->pointsToConstantMemory(Loc, AAQI, OrLocal)
982 : CurrentResult.pointsToConstantMemory(Loc, AAQI, OrLocal);
983 }
984
985 ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) {
986 return AAR ? AAR->getArgModRefInfo(Call, ArgIdx)
987 : CurrentResult.getArgModRefInfo(Call, ArgIdx);
988 }
989
990 FunctionModRefBehavior getModRefBehavior(const CallBase *Call) {
991 return AAR ? AAR->getModRefBehavior(Call)
992 : CurrentResult.getModRefBehavior(Call);
993 }
994
995 FunctionModRefBehavior getModRefBehavior(const Function *F) {
996 return AAR ? AAR->getModRefBehavior(F) : CurrentResult.getModRefBehavior(F);
997 }
998
999 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
1000 AAQueryInfo &AAQI) {
1001 return AAR ? AAR->getModRefInfo(Call, Loc, AAQI)
1002 : CurrentResult.getModRefInfo(Call, Loc, AAQI);
1003 }
1004
1005 ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2,
1006 AAQueryInfo &AAQI) {
1007 return AAR ? AAR->getModRefInfo(Call1, Call2, AAQI)
1008 : CurrentResult.getModRefInfo(Call1, Call2, AAQI);
1009 }
1010 };
1011
1012 explicit AAResultBase() = default;
1013
1014 // Provide all the copy and move constructors so that derived types aren't
1015 // constrained.
1016 AAResultBase(const AAResultBase &Arg) {}
1017 AAResultBase(AAResultBase &&Arg) {}
1018
1019 /// Get a proxy for the best AA result set to query at this time.
1020 ///
1021 /// When this result is part of a larger aggregation, this will proxy to that
1022 /// aggregation. When this result is used in isolation, it will just delegate
1023 /// back to the derived class's implementation.
1024 ///
1025 /// Note that callers of this need to take considerable care to not cause
1026 /// performance problems when they use this routine, in the case of a large
1027 /// number of alias analyses being aggregated, it can be expensive to walk
1028 /// back across the chain.
1029 AAResultsProxy getBestAAResults() { return AAResultsProxy(AAR, derived()); }
1030
1031public:
1032 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
1033 AAQueryInfo &AAQI) {
1034 return MayAlias;
1035 }
1036
1037 bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
1038 bool OrLocal) {
1039 return false;
1040 }
1041
1042 ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) {
1043 return ModRefInfo::ModRef;
1044 }
1045
1046 FunctionModRefBehavior getModRefBehavior(const CallBase *Call) {
1047 return FMRB_UnknownModRefBehavior;
1048 }
1049
1050 FunctionModRefBehavior getModRefBehavior(const Function *F) {
1051 return FMRB_UnknownModRefBehavior;
1052 }
1053
1054 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
1055 AAQueryInfo &AAQI) {
1056 return ModRefInfo::ModRef;
1057 }
1058
1059 ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2,
1060 AAQueryInfo &AAQI) {
1061 return ModRefInfo::ModRef;
1062 }
1063};
1064
1065/// Return true if this pointer is returned by a noalias function.
1066bool isNoAliasCall(const Value *V);
1067
1068/// Return true if this is an argument with the noalias attribute.
1069bool isNoAliasArgument(const Value *V);
1070
1071/// Return true if this pointer refers to a distinct and identifiable object.
1072/// This returns true for:
1073/// Global Variables and Functions (but not Global Aliases)
1074/// Allocas
1075/// ByVal and NoAlias Arguments
1076/// NoAlias returns (e.g. calls to malloc)
1077///
1078bool isIdentifiedObject(const Value *V);
1079
1080/// Return true if V is umabigously identified at the function-level.
1081/// Different IdentifiedFunctionLocals can't alias.
1082/// Further, an IdentifiedFunctionLocal can not alias with any function
1083/// arguments other than itself, which is not necessarily true for
1084/// IdentifiedObjects.
1085bool isIdentifiedFunctionLocal(const Value *V);
1086
1087/// A manager for alias analyses.
1088///
1089/// This class can have analyses registered with it and when run, it will run
1090/// all of them and aggregate their results into single AA results interface
1091/// that dispatches across all of the alias analysis results available.
1092///
1093/// Note that the order in which analyses are registered is very significant.
1094/// That is the order in which the results will be aggregated and queried.
1095///
1096/// This manager effectively wraps the AnalysisManager for registering alias
1097/// analyses. When you register your alias analysis with this manager, it will
1098/// ensure the analysis itself is registered with its AnalysisManager.
1099///
1100/// The result of this analysis is only invalidated if one of the particular
1101/// aggregated AA results end up being invalidated. This removes the need to
1102/// explicitly preserve the results of `AAManager`. Note that analyses should no
1103/// longer be registered once the `AAManager` is run.
1104class AAManager : public AnalysisInfoMixin<AAManager> {
1105public:
1106 using Result = AAResults;
1107
1108 /// Register a specific AA result.
1109 template <typename AnalysisT> void registerFunctionAnalysis() {
1110 ResultGetters.push_back(&getFunctionAAResultImpl<AnalysisT>);
1111 }
1112
1113 /// Register a specific AA result.
1114 template <typename AnalysisT> void registerModuleAnalysis() {
1115 ResultGetters.push_back(&getModuleAAResultImpl<AnalysisT>);
1116 }
1117
1118 Result run(Function &F, FunctionAnalysisManager &AM) {
1119 Result R(AM.getResult<TargetLibraryAnalysis>(F));
1120 for (auto &Getter : ResultGetters)
1121 (*Getter)(F, AM, R);
1122 return R;
1123 }
1124
1125private:
1126 friend AnalysisInfoMixin<AAManager>;
1127
1128 static AnalysisKey Key;
1129
1130 SmallVector<void (*)(Function &F, FunctionAnalysisManager &AM,
1131 AAResults &AAResults),
1132 4> ResultGetters;
1133
1134 template <typename AnalysisT>
1135 static void getFunctionAAResultImpl(Function &F,
1136 FunctionAnalysisManager &AM,
1137 AAResults &AAResults) {
1138 AAResults.addAAResult(AM.template getResult<AnalysisT>(F));
1139 AAResults.addAADependencyID(AnalysisT::ID());
1140 }
1141
1142 template <typename AnalysisT>
1143 static vo