/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp

Bug Summary

File:	lib/Analysis/MemorySSA.cpp
Warning:	line 1139, column 5 Value stored to 'Walker' is never read

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 MemorySSA.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 -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn350071/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/include/clang/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/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++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/lib/Analysis -fdebug-prefix-map=/build/llvm-toolchain-snapshot-8~svn350071=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-12-27-042839-1215-1 -x c++ /build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp -faddrsig

1	//===- MemorySSA.cpp - Memory SSA Builder ---------------------------------===//
2	//
3	// The LLVM Compiler Infrastructure
4	//
5	// This file is distributed under the University of Illinois Open Source
6	// License. See LICENSE.TXT for details.
7	//
8	//===----------------------------------------------------------------------===//
9	//
10	// This file implements the MemorySSA class.
11	//
12	//===----------------------------------------------------------------------===//
13
14	#include "llvm/Analysis/MemorySSA.h"
15	#include "llvm/ADT/DenseMap.h"
16	#include "llvm/ADT/DenseMapInfo.h"
17	#include "llvm/ADT/DenseSet.h"
18	#include "llvm/ADT/DepthFirstIterator.h"
19	#include "llvm/ADT/Hashing.h"
20	#include "llvm/ADT/None.h"
21	#include "llvm/ADT/Optional.h"
22	#include "llvm/ADT/STLExtras.h"
23	#include "llvm/ADT/SmallPtrSet.h"
24	#include "llvm/ADT/SmallVector.h"
25	#include "llvm/ADT/iterator.h"
26	#include "llvm/ADT/iterator_range.h"
27	#include "llvm/Analysis/AliasAnalysis.h"
28	#include "llvm/Analysis/IteratedDominanceFrontier.h"
29	#include "llvm/Analysis/MemoryLocation.h"
30	#include "llvm/Config/llvm-config.h"
31	#include "llvm/IR/AssemblyAnnotationWriter.h"
32	#include "llvm/IR/BasicBlock.h"
33	#include "llvm/IR/CallSite.h"
34	#include "llvm/IR/Dominators.h"
35	#include "llvm/IR/Function.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/LLVMContext.h"
41	#include "llvm/IR/PassManager.h"
42	#include "llvm/IR/Use.h"
43	#include "llvm/Pass.h"
44	#include "llvm/Support/AtomicOrdering.h"
45	#include "llvm/Support/Casting.h"
46	#include "llvm/Support/CommandLine.h"
47	#include "llvm/Support/Compiler.h"
48	#include "llvm/Support/Debug.h"
49	#include "llvm/Support/ErrorHandling.h"
50	#include "llvm/Support/FormattedStream.h"
51	#include "llvm/Support/raw_ostream.h"
52	#include <algorithm>
53	#include <cassert>
54	#include <iterator>
55	#include <memory>
56	#include <utility>
57
58	using namespace llvm;
59
60	#define DEBUG_TYPE"memoryssa" "memoryssa"
61
62	INITIALIZE_PASS_BEGIN(MemorySSAWrapperPass, "memoryssa", "Memory SSA", false,static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry &Registry) {
63	true)static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry &Registry) {
64	INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
65	INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
66	INITIALIZE_PASS_END(MemorySSAWrapperPass, "memoryssa", "Memory SSA", false,PassInfo PI = new PassInfo( "Memory SSA", "memoryssa", & MemorySSAWrapperPass::ID, PassInfo::NormalCtor_t(callDefaultCtor <MemorySSAWrapperPass>), false, true); Registry.registerPass (PI, true); return PI; } static llvm::once_flag InitializeMemorySSAWrapperPassPassFlag ; void llvm::initializeMemorySSAWrapperPassPass(PassRegistry & Registry) { llvm::call_once(InitializeMemorySSAWrapperPassPassFlag , initializeMemorySSAWrapperPassPassOnce, std::ref(Registry)) ; }
67	true)PassInfo PI = new PassInfo( "Memory SSA", "memoryssa", & MemorySSAWrapperPass::ID, PassInfo::NormalCtor_t(callDefaultCtor <MemorySSAWrapperPass>), false, true); Registry.registerPass (PI, true); return PI; } static llvm::once_flag InitializeMemorySSAWrapperPassPassFlag ; void llvm::initializeMemorySSAWrapperPassPass(PassRegistry & Registry) { llvm::call_once(InitializeMemorySSAWrapperPassPassFlag , initializeMemorySSAWrapperPassPassOnce, std::ref(Registry)) ; }
68
69	INITIALIZE_PASS_BEGIN(MemorySSAPrinterLegacyPass, "print-memoryssa",static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry &Registry) {
70	"Memory SSA Printer", false, false)static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry &Registry) {
71	INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
72	INITIALIZE_PASS_END(MemorySSAPrinterLegacyPass, "print-memoryssa",PassInfo PI = new PassInfo( "Memory SSA Printer", "print-memoryssa" , &MemorySSAPrinterLegacyPass::ID, PassInfo::NormalCtor_t (callDefaultCtor<MemorySSAPrinterLegacyPass>), false, false ); Registry.registerPass(PI, true); return PI; } static llvm ::once_flag InitializeMemorySSAPrinterLegacyPassPassFlag; void llvm::initializeMemorySSAPrinterLegacyPassPass(PassRegistry & Registry) { llvm::call_once(InitializeMemorySSAPrinterLegacyPassPassFlag , initializeMemorySSAPrinterLegacyPassPassOnce, std::ref(Registry )); }
73	"Memory SSA Printer", false, false)PassInfo PI = new PassInfo( "Memory SSA Printer", "print-memoryssa" , &MemorySSAPrinterLegacyPass::ID, PassInfo::NormalCtor_t (callDefaultCtor<MemorySSAPrinterLegacyPass>), false, false ); Registry.registerPass(PI, true); return PI; } static llvm ::once_flag InitializeMemorySSAPrinterLegacyPassPassFlag; void llvm::initializeMemorySSAPrinterLegacyPassPass(PassRegistry & Registry) { llvm::call_once(InitializeMemorySSAPrinterLegacyPassPassFlag , initializeMemorySSAPrinterLegacyPassPassOnce, std::ref(Registry )); }
74
75	static cl::opt<unsigned> MaxCheckLimit(
76	"memssa-check-limit", cl::Hidden, cl::init(100),
77	cl::desc("The maximum number of stores/phis MemorySSA"
78	"will consider trying to walk past (default = 100)"));
79
80	// Always verify MemorySSA if expensive checking is enabled.
81	#ifdef EXPENSIVE_CHECKS
82	bool llvm::VerifyMemorySSA = true;
83	#else
84	bool llvm::VerifyMemorySSA = false;
85	#endif
86	static cl::opt<bool, true>
87	VerifyMemorySSAX("verify-memoryssa", cl::location(VerifyMemorySSA),
88	cl::Hidden, cl::desc("Enable verification of MemorySSA."));
89
90	namespace llvm {
91
92	/// An assembly annotator class to print Memory SSA information in
93	/// comments.
94	class MemorySSAAnnotatedWriter : public AssemblyAnnotationWriter {
95	friend class MemorySSA;
96
97	const MemorySSA *MSSA;
98
99	public:
100	MemorySSAAnnotatedWriter(const MemorySSA *M) : MSSA(M) {}
101
102	void emitBasicBlockStartAnnot(const BasicBlock *BB,
103	formatted_raw_ostream &OS) override {
104	if (MemoryAccess *MA = MSSA->getMemoryAccess(BB))
105	OS << "; " << *MA << "\n";
106	}
107
108	void emitInstructionAnnot(const Instruction *I,
109	formatted_raw_ostream &OS) override {
110	if (MemoryAccess *MA = MSSA->getMemoryAccess(I))
111	OS << "; " << *MA << "\n";
112	}
113	};
114
115	} // end namespace llvm
116
117	namespace {
118
119	/// Our current alias analysis API differentiates heavily between calls and
120	/// non-calls, and functions called on one usually assert on the other.
121	/// This class encapsulates the distinction to simplify other code that wants
122	/// "Memory affecting instructions and related data" to use as a key.
123	/// For example, this class is used as a densemap key in the use optimizer.
124	class MemoryLocOrCall {
125	public:
126	bool IsCall = false;
127
128	MemoryLocOrCall(MemoryUseOrDef *MUD)
129	: MemoryLocOrCall(MUD->getMemoryInst()) {}
130	MemoryLocOrCall(const MemoryUseOrDef *MUD)
131	: MemoryLocOrCall(MUD->getMemoryInst()) {}
132
133	MemoryLocOrCall(Instruction *Inst) {
134	if (ImmutableCallSite(Inst)) {
135	IsCall = true;
136	CS = ImmutableCallSite(Inst);
137	} else {
138	IsCall = false;
139	// There is no such thing as a memorylocation for a fence inst, and it is
140	// unique in that regard.
141	if (!isa<FenceInst>(Inst))
142	Loc = MemoryLocation::get(Inst);
143	}
144	}
145
146	explicit MemoryLocOrCall(const MemoryLocation &Loc) : Loc(Loc) {}
147
148	ImmutableCallSite getCS() const {
149	assert(IsCall)((IsCall) ? static_cast<void> (0) : __assert_fail ("IsCall" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 149, __PRETTY_FUNCTION__));
150	return CS;
151	}
152
153	MemoryLocation getLoc() const {
154	assert(!IsCall)((!IsCall) ? static_cast<void> (0) : __assert_fail ("!IsCall" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 154, __PRETTY_FUNCTION__));
155	return Loc;
156	}
157
158	bool operator==(const MemoryLocOrCall &Other) const {
159	if (IsCall != Other.IsCall)
160	return false;
161
162	if (!IsCall)
163	return Loc == Other.Loc;
164
165	if (CS.getCalledValue() != Other.CS.getCalledValue())
166	return false;
167
168	return CS.arg_size() == Other.CS.arg_size() &&
169	std::equal(CS.arg_begin(), CS.arg_end(), Other.CS.arg_begin());
170	}
171
172	private:
173	union {
174	ImmutableCallSite CS;
175	MemoryLocation Loc;
176	};
177	};
178
179	} // end anonymous namespace
180
181	namespace llvm {
182
183	template <> struct DenseMapInfo<MemoryLocOrCall> {
184	static inline MemoryLocOrCall getEmptyKey() {
185	return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getEmptyKey());
186	}
187
188	static inline MemoryLocOrCall getTombstoneKey() {
189	return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getTombstoneKey());
190	}
191
192	static unsigned getHashValue(const MemoryLocOrCall &MLOC) {
193	if (!MLOC.IsCall)
194	return hash_combine(
195	MLOC.IsCall,
196	DenseMapInfo<MemoryLocation>::getHashValue(MLOC.getLoc()));
197
198	hash_code hash =
199	hash_combine(MLOC.IsCall, DenseMapInfo<const Value *>::getHashValue(
200	MLOC.getCS().getCalledValue()));
201
202	for (const Value *Arg : MLOC.getCS().args())
203	hash = hash_combine(hash, DenseMapInfo<const Value *>::getHashValue(Arg));
204	return hash;
205	}
206
207	static bool isEqual(const MemoryLocOrCall &LHS, const MemoryLocOrCall &RHS) {
208	return LHS == RHS;
209	}
210	};
211
212	} // end namespace llvm
213
214	/// This does one-way checks to see if Use could theoretically be hoisted above
215	/// MayClobber. This will not check the other way around.
216	///
217	/// This assumes that, for the purposes of MemorySSA, Use comes directly after
218	/// MayClobber, with no potentially clobbering operations in between them.
219	/// (Where potentially clobbering ops are memory barriers, aliased stores, etc.)
220	static bool areLoadsReorderable(const LoadInst *Use,
221	const LoadInst *MayClobber) {
222	bool VolatileUse = Use->isVolatile();
223	bool VolatileClobber = MayClobber->isVolatile();
224	// Volatile operations may never be reordered with other volatile operations.
225	if (VolatileUse && VolatileClobber)
226	return false;
227	// Otherwise, volatile doesn't matter here. From the language reference:
228	// 'optimizers may change the order of volatile operations relative to
229	// non-volatile operations.'"
230
231	// If a load is seq_cst, it cannot be moved above other loads. If its ordering
232	// is weaker, it can be moved above other loads. We just need to be sure that
233	// MayClobber isn't an acquire load, because loads can't be moved above
234	// acquire loads.
235	//
236	// Note that this explicitly does allow the free reordering of monotonic (or
237	// weaker) loads of the same address.
238	bool SeqCstUse = Use->getOrdering() == AtomicOrdering::SequentiallyConsistent;
239	bool MayClobberIsAcquire = isAtLeastOrStrongerThan(MayClobber->getOrdering(),
240	AtomicOrdering::Acquire);
241	return !(SeqCstUse \|\| MayClobberIsAcquire);
242	}
243
244	namespace {
245
246	struct ClobberAlias {
247	bool IsClobber;
248	Optional<AliasResult> AR;
249	};
250
251	} // end anonymous namespace
252
253	// Return a pair of {IsClobber (bool), AR (AliasResult)}. It relies on AR being
254	// ignored if IsClobber = false.
255	static ClobberAlias instructionClobbersQuery(const MemoryDef *MD,
256	const MemoryLocation &UseLoc,
257	const Instruction *UseInst,
258	AliasAnalysis &AA) {
259	Instruction *DefInst = MD->getMemoryInst();
260	assert(DefInst && "Defining instruction not actually an instruction")((DefInst && "Defining instruction not actually an instruction" ) ? static_cast<void> (0) : __assert_fail ("DefInst && \"Defining instruction not actually an instruction\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 260, __PRETTY_FUNCTION__));
261	ImmutableCallSite UseCS(UseInst);
262	Optional<AliasResult> AR;
263
264	if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(DefInst)) {
265	// These intrinsics will show up as affecting memory, but they are just
266	// markers, mostly.
267	//
268	// FIXME: We probably don't actually want MemorySSA to model these at all
269	// (including creating MemoryAccesses for them): we just end up inventing
270	// clobbers where they don't really exist at all. Please see D43269 for
271	// context.
272	switch (II->getIntrinsicID()) {
273	case Intrinsic::lifetime_start:
274	if (UseCS)
275	return {false, NoAlias};
276	AR = AA.alias(MemoryLocation(II->getArgOperand(1)), UseLoc);
277	return {AR != NoAlias, AR};
278	case Intrinsic::lifetime_end:
279	case Intrinsic::invariant_start:
280	case Intrinsic::invariant_end:
281	case Intrinsic::assume:
282	return {false, NoAlias};
283	default:
284	break;
285	}
286	}
287
288	if (UseCS) {
289	ModRefInfo I = AA.getModRefInfo(DefInst, UseCS);
290	AR = isMustSet(I) ? MustAlias : MayAlias;
291	return {isModOrRefSet(I), AR};
292	}
293
294	if (auto *DefLoad = dyn_cast<LoadInst>(DefInst))
295	if (auto *UseLoad = dyn_cast<LoadInst>(UseInst))
296	return {!areLoadsReorderable(UseLoad, DefLoad), MayAlias};
297
298	ModRefInfo I = AA.getModRefInfo(DefInst, UseLoc);
299	AR = isMustSet(I) ? MustAlias : MayAlias;
300	return {isModSet(I), AR};
301	}
302
303	static ClobberAlias instructionClobbersQuery(MemoryDef *MD,
304	const MemoryUseOrDef *MU,
305	const MemoryLocOrCall &UseMLOC,
306	AliasAnalysis &AA) {
307	// FIXME: This is a temporary hack to allow a single instructionClobbersQuery
308	// to exist while MemoryLocOrCall is pushed through places.
309	if (UseMLOC.IsCall)
310	return instructionClobbersQuery(MD, MemoryLocation(), MU->getMemoryInst(),
311	AA);
312	return instructionClobbersQuery(MD, UseMLOC.getLoc(), MU->getMemoryInst(),
313	AA);
314	}
315
316	// Return true when MD may alias MU, return false otherwise.
317	bool MemorySSAUtil::defClobbersUseOrDef(MemoryDef MD, const MemoryUseOrDef MU,
318	AliasAnalysis &AA) {
319	return instructionClobbersQuery(MD, MU, MemoryLocOrCall(MU), AA).IsClobber;
320	}
321
322	namespace {
323
324	struct UpwardsMemoryQuery {
325	// True if our original query started off as a call
326	bool IsCall = false;
327	// The pointer location we started the query with. This will be empty if
328	// IsCall is true.
329	MemoryLocation StartingLoc;
330	// This is the instruction we were querying about.
331	const Instruction *Inst = nullptr;
332	// The MemoryAccess we actually got called with, used to test local domination
333	const MemoryAccess *OriginalAccess = nullptr;
334	Optional<AliasResult> AR = MayAlias;
335
336	UpwardsMemoryQuery() = default;
337
338	UpwardsMemoryQuery(const Instruction Inst, const MemoryAccess Access)
339	: IsCall(ImmutableCallSite(Inst)), Inst(Inst), OriginalAccess(Access) {
340	if (!IsCall)
341	StartingLoc = MemoryLocation::get(Inst);
342	}
343	};
344
345	} // end anonymous namespace
346
347	static bool lifetimeEndsAt(MemoryDef *MD, const MemoryLocation &Loc,
348	AliasAnalysis &AA) {
349	Instruction *Inst = MD->getMemoryInst();
350	if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
351	switch (II->getIntrinsicID()) {
352	case Intrinsic::lifetime_end:
353	return AA.isMustAlias(MemoryLocation(II->getArgOperand(1)), Loc);
354	default:
355	return false;
356	}
357	}
358	return false;
359	}
360
361	static bool isUseTriviallyOptimizableToLiveOnEntry(AliasAnalysis &AA,
362	const Instruction *I) {
363	// If the memory can't be changed, then loads of the memory can't be
364	// clobbered.
365	return isa<LoadInst>(I) && (I->getMetadata(LLVMContext::MD_invariant_load) \|\|
366	AA.pointsToConstantMemory(cast<LoadInst>(I)->
367	getPointerOperand()));
368	}
369
370	/// Verifies that `Start` is clobbered by `ClobberAt`, and that nothing
371	/// inbetween `Start` and `ClobberAt` can clobbers `Start`.
372	///
373	/// This is meant to be as simple and self-contained as possible. Because it
374	/// uses no cache, etc., it can be relatively expensive.
375	///
376	/// \param Start The MemoryAccess that we want to walk from.
377	/// \param ClobberAt A clobber for Start.
378	/// \param StartLoc The MemoryLocation for Start.
379	/// \param MSSA The MemorySSA instance that Start and ClobberAt belong to.
380	/// \param Query The UpwardsMemoryQuery we used for our search.
381	/// \param AA The AliasAnalysis we used for our search.
382	/// \param AllowImpreciseClobber Always false, unless we do relaxed verify.
383	static void
384	checkClobberSanity(const MemoryAccess Start, MemoryAccess ClobberAt,
385	const MemoryLocation &StartLoc, const MemorySSA &MSSA,
386	const UpwardsMemoryQuery &Query, AliasAnalysis &AA,
387	bool AllowImpreciseClobber = false) {
388	assert(MSSA.dominates(ClobberAt, Start) && "Clobber doesn't dominate start?")((MSSA.dominates(ClobberAt, Start) && "Clobber doesn't dominate start?" ) ? static_cast<void> (0) : __assert_fail ("MSSA.dominates(ClobberAt, Start) && \"Clobber doesn't dominate start?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 388, __PRETTY_FUNCTION__));
389
390	if (MSSA.isLiveOnEntryDef(Start)) {
391	assert(MSSA.isLiveOnEntryDef(ClobberAt) &&((MSSA.isLiveOnEntryDef(ClobberAt) && "liveOnEntry must clobber itself" ) ? static_cast<void> (0) : __assert_fail ("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 392, __PRETTY_FUNCTION__))
392	"liveOnEntry must clobber itself")((MSSA.isLiveOnEntryDef(ClobberAt) && "liveOnEntry must clobber itself" ) ? static_cast<void> (0) : __assert_fail ("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 392, __PRETTY_FUNCTION__));
393	return;
394	}
395
396	bool FoundClobber = false;
397	DenseSet<ConstMemoryAccessPair> VisitedPhis;
398	SmallVector<ConstMemoryAccessPair, 8> Worklist;
399	Worklist.emplace_back(Start, StartLoc);
400	// Walk all paths from Start to ClobberAt, while looking for clobbers. If one
401	// is found, complain.
402	while (!Worklist.empty()) {
403	auto MAP = Worklist.pop_back_val();
404	// All we care about is that nothing from Start to ClobberAt clobbers Start.
405	// We learn nothing from revisiting nodes.
406	if (!VisitedPhis.insert(MAP).second)
407	continue;
408
409	for (const auto *MA : def_chain(MAP.first)) {
410	if (MA == ClobberAt) {
411	if (const auto *MD = dyn_cast<MemoryDef>(MA)) {
412	// instructionClobbersQuery isn't essentially free, so don't use `\|=`,
413	// since it won't let us short-circuit.
414	//
415	// Also, note that this can't be hoisted out of the `Worklist` loop,
416	// since MD may only act as a clobber for 1 of N MemoryLocations.
417	FoundClobber = FoundClobber \|\| MSSA.isLiveOnEntryDef(MD);
418	if (!FoundClobber) {
419	ClobberAlias CA =
420	instructionClobbersQuery(MD, MAP.second, Query.Inst, AA);
421	if (CA.IsClobber) {
422	FoundClobber = true;
423	// Not used: CA.AR;
424	}
425	}
426	}
427	break;
428	}
429
430	// We should never hit liveOnEntry, unless it's the clobber.
431	assert(!MSSA.isLiveOnEntryDef(MA) && "Hit liveOnEntry before clobber?")((!MSSA.isLiveOnEntryDef(MA) && "Hit liveOnEntry before clobber?" ) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(MA) && \"Hit liveOnEntry before clobber?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 431, __PRETTY_FUNCTION__));
432
433	if (const auto *MD = dyn_cast<MemoryDef>(MA)) {
434	// If Start is a Def, skip self.
435	if (MD == Start)
436	continue;
437
438	assert(!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA)((!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) . IsClobber && "Found clobber before reaching ClobberAt!" ) ? static_cast<void> (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) .IsClobber && \"Found clobber before reaching ClobberAt!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 440, __PRETTY_FUNCTION__))
439	.IsClobber &&((!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) . IsClobber && "Found clobber before reaching ClobberAt!" ) ? static_cast<void> (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) .IsClobber && \"Found clobber before reaching ClobberAt!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 440, __PRETTY_FUNCTION__))
440	"Found clobber before reaching ClobberAt!")((!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) . IsClobber && "Found clobber before reaching ClobberAt!" ) ? static_cast<void> (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) .IsClobber && \"Found clobber before reaching ClobberAt!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 440, __PRETTY_FUNCTION__));
441	continue;
442	}
443
444	if (const auto *MU = dyn_cast<MemoryUse>(MA)) {
445	(void)MU;
446	assert (MU == Start &&((MU == Start && "Can only find use in def chain if Start is a use" ) ? static_cast<void> (0) : __assert_fail ("MU == Start && \"Can only find use in def chain if Start is a use\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 447, __PRETTY_FUNCTION__))
447	"Can only find use in def chain if Start is a use")((MU == Start && "Can only find use in def chain if Start is a use" ) ? static_cast<void> (0) : __assert_fail ("MU == Start && \"Can only find use in def chain if Start is a use\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 447, __PRETTY_FUNCTION__));
448	continue;
449	}
450
451	assert(isa<MemoryPhi>(MA))((isa<MemoryPhi>(MA)) ? static_cast<void> (0) : __assert_fail ("isa<MemoryPhi>(MA)", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 451, __PRETTY_FUNCTION__));
452	Worklist.append(
453	upward_defs_begin({const_cast<MemoryAccess *>(MA), MAP.second}),
454	upward_defs_end());
455	}
456	}
457
458	// If the verify is done following an optimization, it's possible that
459	// ClobberAt was a conservative clobbering, that we can now infer is not a
460	// true clobbering access. Don't fail the verify if that's the case.
461	// We do have accesses that claim they're optimized, but could be optimized
462	// further. Updating all these can be expensive, so allow it for now (FIXME).
463	if (AllowImpreciseClobber)
464	return;
465
466	// If ClobberAt is a MemoryPhi, we can assume something above it acted as a
467	// clobber. Otherwise, `ClobberAt` should've acted as a clobber at some point.
468	assert((isa<MemoryPhi>(ClobberAt) \|\| FoundClobber) &&(((isa<MemoryPhi>(ClobberAt) \|\| FoundClobber) && "ClobberAt never acted as a clobber") ? static_cast<void> (0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) \|\| FoundClobber) && \"ClobberAt never acted as a clobber\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 469, __PRETTY_FUNCTION__))
469	"ClobberAt never acted as a clobber")(((isa<MemoryPhi>(ClobberAt) \|\| FoundClobber) && "ClobberAt never acted as a clobber") ? static_cast<void> (0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) \|\| FoundClobber) && \"ClobberAt never acted as a clobber\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 469, __PRETTY_FUNCTION__));
470	}
471
472	namespace {
473
474	/// Our algorithm for walking (and trying to optimize) clobbers, all wrapped up
475	/// in one class.
476	class ClobberWalker {
477	/// Save a few bytes by using unsigned instead of size_t.
478	using ListIndex = unsigned;
479
480	/// Represents a span of contiguous MemoryDefs, potentially ending in a
481	/// MemoryPhi.
482	struct DefPath {
483	MemoryLocation Loc;
484	// Note that, because we always walk in reverse, Last will always dominate
485	// First. Also note that First and Last are inclusive.
486	MemoryAccess *First;
487	MemoryAccess *Last;
488	Optional<ListIndex> Previous;
489
490	DefPath(const MemoryLocation &Loc, MemoryAccess First, MemoryAccess Last,
491	Optional<ListIndex> Previous)
492	: Loc(Loc), First(First), Last(Last), Previous(Previous) {}
493
494	DefPath(const MemoryLocation &Loc, MemoryAccess *Init,
495	Optional<ListIndex> Previous)
496	: DefPath(Loc, Init, Init, Previous) {}
497	};
498
499	const MemorySSA &MSSA;
500	AliasAnalysis &AA;
501	DominatorTree &DT;
502	UpwardsMemoryQuery *Query;
503
504	// Phi optimization bookkeeping
505	SmallVector<DefPath, 32> Paths;
506	DenseSet<ConstMemoryAccessPair> VisitedPhis;
507
508	/// Find the nearest def or phi that `From` can legally be optimized to.
509	const MemoryAccess getWalkTarget(const MemoryPhi From) const {
510	assert(From->getNumOperands() && "Phi with no operands?")((From->getNumOperands() && "Phi with no operands?" ) ? static_cast<void> (0) : __assert_fail ("From->getNumOperands() && \"Phi with no operands?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 510, __PRETTY_FUNCTION__));
511
512	BasicBlock *BB = From->getBlock();
513	MemoryAccess *Result = MSSA.getLiveOnEntryDef();
514	DomTreeNode *Node = DT.getNode(BB);
515	while ((Node = Node->getIDom())) {
516	auto *Defs = MSSA.getBlockDefs(Node->getBlock());
517	if (Defs)
518	return &*Defs->rbegin();
519	}
520	return Result;
521	}
522
523	/// Result of calling walkToPhiOrClobber.
524	struct UpwardsWalkResult {
525	/// The "Result" of the walk. Either a clobber, the last thing we walked, or
526	/// both. Include alias info when clobber found.
527	MemoryAccess *Result;
528	bool IsKnownClobber;
529	Optional<AliasResult> AR;
530	};
531
532	/// Walk to the next Phi or Clobber in the def chain starting at Desc.Last.
533	/// This will update Desc.Last as it walks. It will (optionally) also stop at
534	/// StopAt.
535	///
536	/// This does not test for whether StopAt is a clobber
537	UpwardsWalkResult
538	walkToPhiOrClobber(DefPath &Desc,
539	const MemoryAccess *StopAt = nullptr) const {
540	assert(!isa<MemoryUse>(Desc.Last) && "Uses don't exist in my world")((!isa<MemoryUse>(Desc.Last) && "Uses don't exist in my world" ) ? static_cast<void> (0) : __assert_fail ("!isa<MemoryUse>(Desc.Last) && \"Uses don't exist in my world\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 540, __PRETTY_FUNCTION__));
541
542	for (MemoryAccess *Current : def_chain(Desc.Last)) {
543	Desc.Last = Current;
544	if (Current == StopAt)
545	return {Current, false, MayAlias};
546
547	if (auto *MD = dyn_cast<MemoryDef>(Current)) {
548	if (MSSA.isLiveOnEntryDef(MD))
549	return {MD, true, MustAlias};
550	ClobberAlias CA =
551	instructionClobbersQuery(MD, Desc.Loc, Query->Inst, AA);
552	if (CA.IsClobber)
553	return {MD, true, CA.AR};
554	}
555	}
556
557	assert(isa<MemoryPhi>(Desc.Last) &&((isa<MemoryPhi>(Desc.Last) && "Ended at a non-clobber that's not a phi?" ) ? static_cast<void> (0) : __assert_fail ("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 558, __PRETTY_FUNCTION__))
558	"Ended at a non-clobber that's not a phi?")((isa<MemoryPhi>(Desc.Last) && "Ended at a non-clobber that's not a phi?" ) ? static_cast<void> (0) : __assert_fail ("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 558, __PRETTY_FUNCTION__));
559	return {Desc.Last, false, MayAlias};
560	}
561
562	void addSearches(MemoryPhi *Phi, SmallVectorImpl<ListIndex> &PausedSearches,
563	ListIndex PriorNode) {
564	auto UpwardDefs = make_range(upward_defs_begin({Phi, Paths[PriorNode].Loc}),
565	upward_defs_end());
566	for (const MemoryAccessPair &P : UpwardDefs) {
567	PausedSearches.push_back(Paths.size());
568	Paths.emplace_back(P.second, P.first, PriorNode);
569	}
570	}
571
572	/// Represents a search that terminated after finding a clobber. This clobber
573	/// may or may not be present in the path of defs from LastNode..SearchStart,
574	/// since it may have been retrieved from cache.
575	struct TerminatedPath {
576	MemoryAccess *Clobber;
577	ListIndex LastNode;
578	};
579
580	/// Get an access that keeps us from optimizing to the given phi.
581	///
582	/// PausedSearches is an array of indices into the Paths array. Its incoming
583	/// value is the indices of searches that stopped at the last phi optimization
584	/// target. It's left in an unspecified state.
585	///
586	/// If this returns None, NewPaused is a vector of searches that terminated
587	/// at StopWhere. Otherwise, NewPaused is left in an unspecified state.
588	Optional<TerminatedPath>
589	getBlockingAccess(const MemoryAccess *StopWhere,
590	SmallVectorImpl<ListIndex> &PausedSearches,
591	SmallVectorImpl<ListIndex> &NewPaused,
592	SmallVectorImpl<TerminatedPath> &Terminated) {
593	assert(!PausedSearches.empty() && "No searches to continue?")((!PausedSearches.empty() && "No searches to continue?" ) ? static_cast<void> (0) : __assert_fail ("!PausedSearches.empty() && \"No searches to continue?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 593, __PRETTY_FUNCTION__));
594
595	// BFS vs DFS really doesn't make a difference here, so just do a DFS with
596	// PausedSearches as our stack.
597	while (!PausedSearches.empty()) {
598	ListIndex PathIndex = PausedSearches.pop_back_val();
599	DefPath &Node = Paths[PathIndex];
600
601	// If we've already visited this path with this MemoryLocation, we don't
602	// need to do so again.
603	//
604	// NOTE: That we just drop these paths on the ground makes caching
605	// behavior sporadic. e.g. given a diamond:
606	// A
607	// B C
608	// D
609	//
610	// ...If we walk D, B, A, C, we'll only cache the result of phi
611	// optimization for A, B, and D; C will be skipped because it dies here.
612	// This arguably isn't the worst thing ever, since:
613	// - We generally query things in a top-down order, so if we got below D
614	// without needing cache entries for {C, MemLoc}, then chances are
615	// that those cache entries would end up ultimately unused.
616	// - We still cache things for A, so C only needs to walk up a bit.
617	// If this behavior becomes problematic, we can fix without a ton of extra
618	// work.
619	if (!VisitedPhis.insert({Node.Last, Node.Loc}).second)
620	continue;
621
622	UpwardsWalkResult Res = walkToPhiOrClobber(Node, /StopAt=/StopWhere);
623	if (Res.IsKnownClobber) {
624	assert(Res.Result != StopWhere)((Res.Result != StopWhere) ? static_cast<void> (0) : __assert_fail ("Res.Result != StopWhere", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 624, __PRETTY_FUNCTION__));
625	// If this wasn't a cache hit, we hit a clobber when walking. That's a
626	// failure.
627	TerminatedPath Term{Res.Result, PathIndex};
628	if (!MSSA.dominates(Res.Result, StopWhere))
629	return Term;
630
631	// Otherwise, it's a valid thing to potentially optimize to.
632	Terminated.push_back(Term);
633	continue;
634	}
635
636	if (Res.Result == StopWhere) {
637	// We've hit our target. Save this path off for if we want to continue
638	// walking.
639	NewPaused.push_back(PathIndex);
640	continue;
641	}
642
643	assert(!MSSA.isLiveOnEntryDef(Res.Result) && "liveOnEntry is a clobber")((!MSSA.isLiveOnEntryDef(Res.Result) && "liveOnEntry is a clobber" ) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(Res.Result) && \"liveOnEntry is a clobber\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 643, __PRETTY_FUNCTION__));
644	addSearches(cast<MemoryPhi>(Res.Result), PausedSearches, PathIndex);
645	}
646
647	return None;
648	}
649
650	template <typename T, typename Walker>
651	struct generic_def_path_iterator
652	: public iterator_facade_base<generic_def_path_iterator<T, Walker>,
653	std::forward_iterator_tag, T *> {
654	generic_def_path_iterator() = default;
655	generic_def_path_iterator(Walker *W, ListIndex N) : W(W), N(N) {}
656
657	T &operator*() const { return curNode(); }
658
659	generic_def_path_iterator &operator++() {
660	N = curNode().Previous;
661	return *this;
662	}
663
664	bool operator==(const generic_def_path_iterator &O) const {
665	if (N.hasValue() != O.N.hasValue())
666	return false;
667	return !N.hasValue() \|\| N == O.N;
668	}
669
670	private:
671	T &curNode() const { return W->Paths[*N]; }
672
673	Walker *W = nullptr;
674	Optional<ListIndex> N = None;
675	};
676
677	using def_path_iterator = generic_def_path_iterator<DefPath, ClobberWalker>;
678	using const_def_path_iterator =
679	generic_def_path_iterator<const DefPath, const ClobberWalker>;
680
681	iterator_range<def_path_iterator> def_path(ListIndex From) {
682	return make_range(def_path_iterator(this, From), def_path_iterator());
683	}
684
685	iterator_range<const_def_path_iterator> const_def_path(ListIndex From) const {
686	return make_range(const_def_path_iterator(this, From),
687	const_def_path_iterator());
688	}
689
690	struct OptznResult {
691	/// The path that contains our result.
692	TerminatedPath PrimaryClobber;
693	/// The paths that we can legally cache back from, but that aren't
694	/// necessarily the result of the Phi optimization.
695	SmallVector<TerminatedPath, 4> OtherClobbers;
696	};
697
698	ListIndex defPathIndex(const DefPath &N) const {
699	// The assert looks nicer if we don't need to do &N
700	const DefPath *NP = &N;
701	assert(!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() &&((!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && "Out of bounds DefPath!" ) ? static_cast<void> (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 702, __PRETTY_FUNCTION__))
702	"Out of bounds DefPath!")((!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && "Out of bounds DefPath!" ) ? static_cast<void> (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 702, __PRETTY_FUNCTION__));
703	return NP - &Paths.front();
704	}
705
706	/// Try to optimize a phi as best as we can. Returns a SmallVector of Paths
707	/// that act as legal clobbers. Note that this won't return all clobbers.
708	///
709	/// Phi optimization algorithm tl;dr:
710	/// - Find the earliest def/phi, A, we can optimize to
711	/// - Find if all paths from the starting memory access ultimately reach A
712	/// - If not, optimization isn't possible.
713	/// - Otherwise, walk from A to another clobber or phi, A'.
714	/// - If A' is a def, we're done.
715	/// - If A' is a phi, try to optimize it.
716	///
717	/// A path is a series of {MemoryAccess, MemoryLocation} pairs. A path
718	/// terminates when a MemoryAccess that clobbers said MemoryLocation is found.
719	OptznResult tryOptimizePhi(MemoryPhi Phi, MemoryAccess Start,
720	const MemoryLocation &Loc) {
721	assert(Paths.empty() && VisitedPhis.empty() &&((Paths.empty() && VisitedPhis.empty() && "Reset the optimization state." ) ? static_cast<void> (0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 722, __PRETTY_FUNCTION__))
722	"Reset the optimization state.")((Paths.empty() && VisitedPhis.empty() && "Reset the optimization state." ) ? static_cast<void> (0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 722, __PRETTY_FUNCTION__));
723
724	Paths.emplace_back(Loc, Start, Phi, None);
725	// Stores how many "valid" optimization nodes we had prior to calling
726	// addSearches/getBlockingAccess. Necessary for caching if we had a blocker.
727	auto PriorPathsSize = Paths.size();
728
729	SmallVector<ListIndex, 16> PausedSearches;
730	SmallVector<ListIndex, 8> NewPaused;
731	SmallVector<TerminatedPath, 4> TerminatedPaths;
732
733	addSearches(Phi, PausedSearches, 0);
734
735	// Moves the TerminatedPath with the "most dominated" Clobber to the end of
736	// Paths.
737	auto MoveDominatedPathToEnd = [&](SmallVectorImpl<TerminatedPath> &Paths) {
738	assert(!Paths.empty() && "Need a path to move")((!Paths.empty() && "Need a path to move") ? static_cast <void> (0) : __assert_fail ("!Paths.empty() && \"Need a path to move\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 738, __PRETTY_FUNCTION__));
739	auto Dom = Paths.begin();
740	for (auto I = std::next(Dom), E = Paths.end(); I != E; ++I)
741	if (!MSSA.dominates(I->Clobber, Dom->Clobber))
742	Dom = I;
743	auto Last = Paths.end() - 1;
744	if (Last != Dom)
745	std::iter_swap(Last, Dom);
746	};
747
748	MemoryPhi *Current = Phi;
749	while (true) {
750	assert(!MSSA.isLiveOnEntryDef(Current) &&((!MSSA.isLiveOnEntryDef(Current) && "liveOnEntry wasn't treated as a clobber?" ) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 751, __PRETTY_FUNCTION__))
751	"liveOnEntry wasn't treated as a clobber?")((!MSSA.isLiveOnEntryDef(Current) && "liveOnEntry wasn't treated as a clobber?" ) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 751, __PRETTY_FUNCTION__));
752
753	const auto *Target = getWalkTarget(Current);
754	// If a TerminatedPath doesn't dominate Target, then it wasn't a legal
755	// optimization for the prior phi.
756	assert(all_of(TerminatedPaths, [&](const TerminatedPath &P) {((all_of(TerminatedPaths, [&](const TerminatedPath &P ) { return MSSA.dominates(P.Clobber, Target); })) ? static_cast <void> (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 758, __PRETTY_FUNCTION__))
757	return MSSA.dominates(P.Clobber, Target);((all_of(TerminatedPaths, [&](const TerminatedPath &P ) { return MSSA.dominates(P.Clobber, Target); })) ? static_cast <void> (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 758, __PRETTY_FUNCTION__))
758	}))((all_of(TerminatedPaths, [&](const TerminatedPath &P ) { return MSSA.dominates(P.Clobber, Target); })) ? static_cast <void> (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 758, __PRETTY_FUNCTION__));
759
760	// FIXME: This is broken, because the Blocker may be reported to be
761	// liveOnEntry, and we'll happily wait for that to disappear (read: never)
762	// For the moment, this is fine, since we do nothing with blocker info.
763	if (Optional<TerminatedPath> Blocker = getBlockingAccess(
764	Target, PausedSearches, NewPaused, TerminatedPaths)) {
765
766	// Find the node we started at. We can't search based on N->Last, since
767	// we may have gone around a loop with a different MemoryLocation.
768	auto Iter = find_if(def_path(Blocker->LastNode), [&](const DefPath &N) {
769	return defPathIndex(N) < PriorPathsSize;
770	});
771	assert(Iter != def_path_iterator())((Iter != def_path_iterator()) ? static_cast<void> (0) : __assert_fail ("Iter != def_path_iterator()", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 771, __PRETTY_FUNCTION__));
772
773	DefPath &CurNode = *Iter;
774	assert(CurNode.Last == Current)((CurNode.Last == Current) ? static_cast<void> (0) : __assert_fail ("CurNode.Last == Current", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 774, __PRETTY_FUNCTION__));
775
776	// Two things:
777	// A. We can't reliably cache all of NewPaused back. Consider a case
778	// where we have two paths in NewPaused; one of which can't optimize
779	// above this phi, whereas the other can. If we cache the second path
780	// back, we'll end up with suboptimal cache entries. We can handle
781	// cases like this a bit better when we either try to find all
782	// clobbers that block phi optimization, or when our cache starts
783	// supporting unfinished searches.
784	// B. We can't reliably cache TerminatedPaths back here without doing
785	// extra checks; consider a case like:
786	// T
787	// / \
788	// D C
789	// \ /
790	// S
791	// Where T is our target, C is a node with a clobber on it, D is a
792	// diamond (with a clobber only on the left or right node, N), and
793	// S is our start. Say we walk to D, through the node opposite N
794	// (read: ignoring the clobber), and see a cache entry in the top
795	// node of D. That cache entry gets put into TerminatedPaths. We then
796	// walk up to C (N is later in our worklist), find the clobber, and
797	// quit. If we append TerminatedPaths to OtherClobbers, we'll cache
798	// the bottom part of D to the cached clobber, ignoring the clobber
799	// in N. Again, this problem goes away if we start tracking all
800	// blockers for a given phi optimization.
801	TerminatedPath Result{CurNode.Last, defPathIndex(CurNode)};
802	return {Result, {}};
803	}
804
805	// If there's nothing left to search, then all paths led to valid clobbers
806	// that we got from our cache; pick the nearest to the start, and allow
807	// the rest to be cached back.
808	if (NewPaused.empty()) {
809	MoveDominatedPathToEnd(TerminatedPaths);
810	TerminatedPath Result = TerminatedPaths.pop_back_val();
811	return {Result, std::move(TerminatedPaths)};
812	}
813
814	MemoryAccess *DefChainEnd = nullptr;
815	SmallVector<TerminatedPath, 4> Clobbers;
816	for (ListIndex Paused : NewPaused) {
817	UpwardsWalkResult WR = walkToPhiOrClobber(Paths[Paused]);
818	if (WR.IsKnownClobber)
819	Clobbers.push_back({WR.Result, Paused});
820	else
821	// Micro-opt: If we hit the end of the chain, save it.
822	DefChainEnd = WR.Result;
823	}
824
825	if (!TerminatedPaths.empty()) {
826	// If we couldn't find the dominating phi/liveOnEntry in the above loop,
827	// do it now.
828	if (!DefChainEnd)
829	for (auto MA : def_chain(const_cast<MemoryAccess >(Target)))
830	DefChainEnd = MA;
831
832	// If any of the terminated paths don't dominate the phi we'll try to
833	// optimize, we need to figure out what they are and quit.
834	const BasicBlock *ChainBB = DefChainEnd->getBlock();
835	for (const TerminatedPath &TP : TerminatedPaths) {
836	// Because we know that DefChainEnd is as "high" as we can go, we
837	// don't need local dominance checks; BB dominance is sufficient.
838	if (DT.dominates(ChainBB, TP.Clobber->getBlock()))
839	Clobbers.push_back(TP);
840	}
841	}
842
843	// If we have clobbers in the def chain, find the one closest to Current
844	// and quit.
845	if (!Clobbers.empty()) {
846	MoveDominatedPathToEnd(Clobbers);
847	TerminatedPath Result = Clobbers.pop_back_val();
848	return {Result, std::move(Clobbers)};
849	}
850
851	assert(all_of(NewPaused,((all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })) ? static_cast<void> (0) : __assert_fail ("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 852, __PRETTY_FUNCTION__))
852	[&](ListIndex I) { return Paths[I].Last == DefChainEnd; }))((all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })) ? static_cast<void> (0) : __assert_fail ("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 852, __PRETTY_FUNCTION__));
853
854	// Because liveOnEntry is a clobber, this must be a phi.
855	auto *DefChainPhi = cast<MemoryPhi>(DefChainEnd);
856
857	PriorPathsSize = Paths.size();
858	PausedSearches.clear();
859	for (ListIndex I : NewPaused)
860	addSearches(DefChainPhi, PausedSearches, I);
861	NewPaused.clear();
862
863	Current = DefChainPhi;
864	}
865	}
866
867	void verifyOptResult(const OptznResult &R) const {
868	assert(all_of(R.OtherClobbers, [&](const TerminatedPath &P) {((all_of(R.OtherClobbers, [&](const TerminatedPath &P ) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber ); })) ? static_cast<void> (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 870, __PRETTY_FUNCTION__))
869	return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber);((all_of(R.OtherClobbers, [&](const TerminatedPath &P ) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber ); })) ? static_cast<void> (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 870, __PRETTY_FUNCTION__))
870	}))((all_of(R.OtherClobbers, [&](const TerminatedPath &P ) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber ); })) ? static_cast<void> (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 870, __PRETTY_FUNCTION__));
871	}
872
873	void resetPhiOptznState() {
874	Paths.clear();
875	VisitedPhis.clear();
876	}
877
878	public:
879	ClobberWalker(const MemorySSA &MSSA, AliasAnalysis &AA, DominatorTree &DT)
880	: MSSA(MSSA), AA(AA), DT(DT) {}
881
882	/// Finds the nearest clobber for the given query, optimizing phis if
883	/// possible.
884	MemoryAccess findClobber(MemoryAccess Start, UpwardsMemoryQuery &Q) {
885	Query = &Q;
886
887	MemoryAccess *Current = Start;
888	// This walker pretends uses don't exist. If we're handed one, silently grab
889	// its def. (This has the nice side-effect of ensuring we never cache uses)
890	if (auto *MU = dyn_cast<MemoryUse>(Start))
891	Current = MU->getDefiningAccess();
892
893	DefPath FirstDesc(Q.StartingLoc, Current, Current, None);
894	// Fast path for the overly-common case (no crazy phi optimization
895	// necessary)
896	UpwardsWalkResult WalkResult = walkToPhiOrClobber(FirstDesc);
897	MemoryAccess *Result;
898	if (WalkResult.IsKnownClobber) {
899	Result = WalkResult.Result;
900	Q.AR = WalkResult.AR;
901	} else {
902	OptznResult OptRes = tryOptimizePhi(cast<MemoryPhi>(FirstDesc.Last),
903	Current, Q.StartingLoc);
904	verifyOptResult(OptRes);
905	resetPhiOptznState();
906	Result = OptRes.PrimaryClobber.Clobber;
907	}
908
909	#ifdef EXPENSIVE_CHECKS
910	checkClobberSanity(Current, Result, Q.StartingLoc, MSSA, Q, AA);
911	#endif
912	return Result;
913	}
914
915	void verify(const MemorySSA *MSSA) { assert(MSSA == &this->MSSA)((MSSA == &this->MSSA) ? static_cast<void> (0) : __assert_fail ("MSSA == &this->MSSA", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 915, __PRETTY_FUNCTION__)); }
916	};
917
918	struct RenamePassData {
919	DomTreeNode *DTN;
920	DomTreeNode::const_iterator ChildIt;
921	MemoryAccess *IncomingVal;
922
923	RenamePassData(DomTreeNode *D, DomTreeNode::const_iterator It,
924	MemoryAccess *M)
925	: DTN(D), ChildIt(It), IncomingVal(M) {}
926
927	void swap(RenamePassData &RHS) {
928	std::swap(DTN, RHS.DTN);
929	std::swap(ChildIt, RHS.ChildIt);
930	std::swap(IncomingVal, RHS.IncomingVal);
931	}
932	};
933
934	} // end anonymous namespace
935
936	namespace llvm {
937
938	/// A MemorySSAWalker that does AA walks to disambiguate accesses. It no
939	/// longer does caching on its own, but the name has been retained for the
940	/// moment.
941	class MemorySSA::CachingWalker final : public MemorySSAWalker {
942	ClobberWalker Walker;
943
944	MemoryAccess getClobberingMemoryAccess(MemoryAccess , UpwardsMemoryQuery &);
945
946	public:
947	CachingWalker(MemorySSA , AliasAnalysis , DominatorTree *);
948	~CachingWalker() override = default;
949
950	using MemorySSAWalker::getClobberingMemoryAccess;
951
952	MemoryAccess getClobberingMemoryAccess(MemoryAccess ) override;
953	MemoryAccess getClobberingMemoryAccess(MemoryAccess ,
954	const MemoryLocation &) override;
955	void invalidateInfo(MemoryAccess *) override;
956
957	void verify(const MemorySSA *MSSA) override {
958	MemorySSAWalker::verify(MSSA);
959	Walker.verify(MSSA);
960	}
961	};
962
963	} // end namespace llvm
964
965	void MemorySSA::renameSuccessorPhis(BasicBlock BB, MemoryAccess IncomingVal,
966	bool RenameAllUses) {
967	// Pass through values to our successors
968	for (const BasicBlock *S : successors(BB)) {
969	auto It = PerBlockAccesses.find(S);
970	// Rename the phi nodes in our successor block
971	if (It == PerBlockAccesses.end() \|\| !isa<MemoryPhi>(It->second->front()))
972	continue;
973	AccessList *Accesses = It->second.get();
974	auto *Phi = cast<MemoryPhi>(&Accesses->front());
975	if (RenameAllUses) {
976	int PhiIndex = Phi->getBasicBlockIndex(BB);
977	assert(PhiIndex != -1 && "Incomplete phi during partial rename")((PhiIndex != -1 && "Incomplete phi during partial rename" ) ? static_cast<void> (0) : __assert_fail ("PhiIndex != -1 && \"Incomplete phi during partial rename\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 977, __PRETTY_FUNCTION__));
978	Phi->setIncomingValue(PhiIndex, IncomingVal);
979	} else
980	Phi->addIncoming(IncomingVal, BB);
981	}
982	}
983
984	/// Rename a single basic block into MemorySSA form.
985	/// Uses the standard SSA renaming algorithm.
986	/// \returns The new incoming value.
987	MemoryAccess MemorySSA::renameBlock(BasicBlock BB, MemoryAccess *IncomingVal,
988	bool RenameAllUses) {
989	auto It = PerBlockAccesses.find(BB);
990	// Skip most processing if the list is empty.
991	if (It != PerBlockAccesses.end()) {
992	AccessList *Accesses = It->second.get();
993	for (MemoryAccess &L : *Accesses) {
994	if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(&L)) {
995	if (MUD->getDefiningAccess() == nullptr \|\| RenameAllUses)
996	MUD->setDefiningAccess(IncomingVal);
997	if (isa<MemoryDef>(&L))
998	IncomingVal = &L;
999	} else {
1000	IncomingVal = &L;
1001	}
1002	}
1003	}
1004	return IncomingVal;
1005	}
1006
1007	/// This is the standard SSA renaming algorithm.
1008	///
1009	/// We walk the dominator tree in preorder, renaming accesses, and then filling
1010	/// in phi nodes in our successors.
1011	void MemorySSA::renamePass(DomTreeNode Root, MemoryAccess IncomingVal,
1012	SmallPtrSetImpl<BasicBlock *> &Visited,
1013	bool SkipVisited, bool RenameAllUses) {
1014	SmallVector<RenamePassData, 32> WorkStack;
1015	// Skip everything if we already renamed this block and we are skipping.
1016	// Note: You can't sink this into the if, because we need it to occur
1017	// regardless of whether we skip blocks or not.
1018	bool AlreadyVisited = !Visited.insert(Root->getBlock()).second;
1019	if (SkipVisited && AlreadyVisited)
1020	return;
1021
1022	IncomingVal = renameBlock(Root->getBlock(), IncomingVal, RenameAllUses);
1023	renameSuccessorPhis(Root->getBlock(), IncomingVal, RenameAllUses);
1024	WorkStack.push_back({Root, Root->begin(), IncomingVal});
1025
1026	while (!WorkStack.empty()) {
1027	DomTreeNode *Node = WorkStack.back().DTN;
1028	DomTreeNode::const_iterator ChildIt = WorkStack.back().ChildIt;
1029	IncomingVal = WorkStack.back().IncomingVal;
1030
1031	if (ChildIt == Node->end()) {
1032	WorkStack.pop_back();
1033	} else {
1034	DomTreeNode Child = ChildIt;
1035	++WorkStack.back().ChildIt;
1036	BasicBlock *BB = Child->getBlock();
1037	// Note: You can't sink this into the if, because we need it to occur
1038	// regardless of whether we skip blocks or not.
1039	AlreadyVisited = !Visited.insert(BB).second;
1040	if (SkipVisited && AlreadyVisited) {
1041	// We already visited this during our renaming, which can happen when
1042	// being asked to rename multiple blocks. Figure out the incoming val,
1043	// which is the last def.
1044	// Incoming value can only change if there is a block def, and in that
1045	// case, it's the last block def in the list.
1046	if (auto *BlockDefs = getWritableBlockDefs(BB))
1047	IncomingVal = &*BlockDefs->rbegin();
1048	} else
1049	IncomingVal = renameBlock(BB, IncomingVal, RenameAllUses);
1050	renameSuccessorPhis(BB, IncomingVal, RenameAllUses);
1051	WorkStack.push_back({Child, Child->begin(), IncomingVal});
1052	}
1053	}
1054	}
1055
1056	/// This handles unreachable block accesses by deleting phi nodes in
1057	/// unreachable blocks, and marking all other unreachable MemoryAccess's as
1058	/// being uses of the live on entry definition.
1059	void MemorySSA::markUnreachableAsLiveOnEntry(BasicBlock *BB) {
1060	assert(!DT->isReachableFromEntry(BB) &&((!DT->isReachableFromEntry(BB) && "Reachable block found while handling unreachable blocks" ) ? static_cast<void> (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1061, __PRETTY_FUNCTION__))
1061	"Reachable block found while handling unreachable blocks")((!DT->isReachableFromEntry(BB) && "Reachable block found while handling unreachable blocks" ) ? static_cast<void> (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1061, __PRETTY_FUNCTION__));
1062
1063	// Make sure phi nodes in our reachable successors end up with a
1064	// LiveOnEntryDef for our incoming edge, even though our block is forward
1065	// unreachable. We could just disconnect these blocks from the CFG fully,
1066	// but we do not right now.
1067	for (const BasicBlock *S : successors(BB)) {
1068	if (!DT->isReachableFromEntry(S))
1069	continue;
1070	auto It = PerBlockAccesses.find(S);
1071	// Rename the phi nodes in our successor block
1072	if (It == PerBlockAccesses.end() \|\| !isa<MemoryPhi>(It->second->front()))
1073	continue;
1074	AccessList *Accesses = It->second.get();
1075	auto *Phi = cast<MemoryPhi>(&Accesses->front());
1076	Phi->addIncoming(LiveOnEntryDef.get(), BB);
1077	}
1078
1079	auto It = PerBlockAccesses.find(BB);
1080	if (It == PerBlockAccesses.end())
1081	return;
1082
1083	auto &Accesses = It->second;
1084	for (auto AI = Accesses->begin(), AE = Accesses->end(); AI != AE;) {
1085	auto Next = std::next(AI);
1086	// If we have a phi, just remove it. We are going to replace all
1087	// users with live on entry.
1088	if (auto *UseOrDef = dyn_cast<MemoryUseOrDef>(AI))
1089	UseOrDef->setDefiningAccess(LiveOnEntryDef.get());
1090	else
1091	Accesses->erase(AI);
1092	AI = Next;
1093	}
1094	}
1095
1096	MemorySSA::MemorySSA(Function &Func, AliasAnalysis AA, DominatorTree DT)
1097	: AA(AA), DT(DT), F(Func), LiveOnEntryDef(nullptr), Walker(nullptr),
1098	NextID(0) {
1099	buildMemorySSA();
1100	}
1101
1102	MemorySSA::~MemorySSA() {
1103	// Drop all our references
1104	for (const auto &Pair : PerBlockAccesses)
1105	for (MemoryAccess &MA : *Pair.second)
1106	MA.dropAllReferences();
1107	}
1108
1109	MemorySSA::AccessList MemorySSA::getOrCreateAccessList(const BasicBlock BB) {
1110	auto Res = PerBlockAccesses.insert(std::make_pair(BB, nullptr));
1111
1112	if (Res.second)
1113	Res.first->second = llvm::make_unique<AccessList>();
1114	return Res.first->second.get();
1115	}
1116
1117	MemorySSA::DefsList MemorySSA::getOrCreateDefsList(const BasicBlock BB) {
1118	auto Res = PerBlockDefs.insert(std::make_pair(BB, nullptr));
1119
1120	if (Res.second)
1121	Res.first->second = llvm::make_unique<DefsList>();
1122	return Res.first->second.get();
1123	}
1124
1125	namespace llvm {
1126
1127	/// This class is a batch walker of all MemoryUse's in the program, and points
1128	/// their defining access at the thing that actually clobbers them. Because it
1129	/// is a batch walker that touches everything, it does not operate like the
1130	/// other walkers. This walker is basically performing a top-down SSA renaming
1131	/// pass, where the version stack is used as the cache. This enables it to be
1132	/// significantly more time and memory efficient than using the regular walker,
1133	/// which is walking bottom-up.
1134	class MemorySSA::OptimizeUses {
1135	public:
1136	OptimizeUses(MemorySSA MSSA, MemorySSAWalker Walker, AliasAnalysis *AA,
1137	DominatorTree *DT)
1138	: MSSA(MSSA), Walker(Walker), AA(AA), DT(DT) {
1139	Walker = MSSA->getWalker();
	Value stored to 'Walker' is never read
1140	}
1141
1142	void optimizeUses();
1143
1144	private:
1145	/// This represents where a given memorylocation is in the stack.
1146	struct MemlocStackInfo {
1147	// This essentially is keeping track of versions of the stack. Whenever
1148	// the stack changes due to pushes or pops, these versions increase.
1149	unsigned long StackEpoch;
1150	unsigned long PopEpoch;
1151	// This is the lower bound of places on the stack to check. It is equal to
1152	// the place the last stack walk ended.
1153	// Note: Correctness depends on this being initialized to 0, which densemap
1154	// does
1155	unsigned long LowerBound;
1156	const BasicBlock *LowerBoundBlock;
1157	// This is where the last walk for this memory location ended.
1158	unsigned long LastKill;
1159	bool LastKillValid;
1160	Optional<AliasResult> AR;
1161	};
1162
1163	void optimizeUsesInBlock(const BasicBlock *, unsigned long &, unsigned long &,
1164	SmallVectorImpl<MemoryAccess *> &,
1165	DenseMap<MemoryLocOrCall, MemlocStackInfo> &);
1166
1167	MemorySSA *MSSA;
1168	MemorySSAWalker *Walker;
1169	AliasAnalysis *AA;
1170	DominatorTree *DT;
1171	};
1172
1173	} // end namespace llvm
1174
1175	/// Optimize the uses in a given block This is basically the SSA renaming
1176	/// algorithm, with one caveat: We are able to use a single stack for all
1177	/// MemoryUses. This is because the set of possible reaching MemoryDefs is
1178	/// the same for every MemoryUse. The actual clobbering MemoryDef is just
1179	/// going to be some position in that stack of possible ones.
1180	///
1181	/// We track the stack positions that each MemoryLocation needs
1182	/// to check, and last ended at. This is because we only want to check the
1183	/// things that changed since last time. The same MemoryLocation should
1184	/// get clobbered by the same store (getModRefInfo does not use invariantness or
1185	/// things like this, and if they start, we can modify MemoryLocOrCall to
1186	/// include relevant data)
1187	void MemorySSA::OptimizeUses::optimizeUsesInBlock(
1188	const BasicBlock *BB, unsigned long &StackEpoch, unsigned long &PopEpoch,
1189	SmallVectorImpl<MemoryAccess *> &VersionStack,
1190	DenseMap<MemoryLocOrCall, MemlocStackInfo> &LocStackInfo) {
1191
1192	/// If no accesses, nothing to do.
1193	MemorySSA::AccessList *Accesses = MSSA->getWritableBlockAccesses(BB);
1194	if (Accesses == nullptr)
1195	return;
1196
1197	// Pop everything that doesn't dominate the current block off the stack,
1198	// increment the PopEpoch to account for this.
1199	while (true) {
1200	assert(((!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything" ) ? static_cast<void> (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1202, __PRETTY_FUNCTION__))
1201	!VersionStack.empty() &&((!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything" ) ? static_cast<void> (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1202, __PRETTY_FUNCTION__))
1202	"Version stack should have liveOnEntry sentinel dominating everything")((!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything" ) ? static_cast<void> (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1202, __PRETTY_FUNCTION__));
1203	BasicBlock *BackBlock = VersionStack.back()->getBlock();
1204	if (DT->dominates(BackBlock, BB))
1205	break;
1206	while (VersionStack.back()->getBlock() == BackBlock)
1207	VersionStack.pop_back();
1208	++PopEpoch;
1209	}
1210
1211	for (MemoryAccess &MA : *Accesses) {
1212	auto *MU = dyn_cast<MemoryUse>(&MA);
1213	if (!MU) {
1214	VersionStack.push_back(&MA);
1215	++StackEpoch;
1216	continue;
1217	}
1218
1219	if (isUseTriviallyOptimizableToLiveOnEntry(*AA, MU->getMemoryInst())) {
1220	MU->setDefiningAccess(MSSA->getLiveOnEntryDef(), true, None);
1221	continue;
1222	}
1223
1224	MemoryLocOrCall UseMLOC(MU);
1225	auto &LocInfo = LocStackInfo[UseMLOC];
1226	// If the pop epoch changed, it means we've removed stuff from top of
1227	// stack due to changing blocks. We may have to reset the lower bound or
1228	// last kill info.
1229	if (LocInfo.PopEpoch != PopEpoch) {
1230	LocInfo.PopEpoch = PopEpoch;
1231	LocInfo.StackEpoch = StackEpoch;
1232	// If the lower bound was in something that no longer dominates us, we
1233	// have to reset it.
1234	// We can't simply track stack size, because the stack may have had
1235	// pushes/pops in the meantime.
1236	// XXX: This is non-optimal, but only is slower cases with heavily
1237	// branching dominator trees. To get the optimal number of queries would
1238	// be to make lowerbound and lastkill a per-loc stack, and pop it until
1239	// the top of that stack dominates us. This does not seem worth it ATM.
1240	// A much cheaper optimization would be to always explore the deepest
1241	// branch of the dominator tree first. This will guarantee this resets on
1242	// the smallest set of blocks.
1243	if (LocInfo.LowerBoundBlock && LocInfo.LowerBoundBlock != BB &&
1244	!DT->dominates(LocInfo.LowerBoundBlock, BB)) {
1245	// Reset the lower bound of things to check.
1246	// TODO: Some day we should be able to reset to last kill, rather than
1247	// 0.
1248	LocInfo.LowerBound = 0;
1249	LocInfo.LowerBoundBlock = VersionStack[0]->getBlock();
1250	LocInfo.LastKillValid = false;
1251	}
1252	} else if (LocInfo.StackEpoch != StackEpoch) {
1253	// If all that has changed is the StackEpoch, we only have to check the
1254	// new things on the stack, because we've checked everything before. In
1255	// this case, the lower bound of things to check remains the same.
1256	LocInfo.PopEpoch = PopEpoch;
1257	LocInfo.StackEpoch = StackEpoch;
1258	}
1259	if (!LocInfo.LastKillValid) {
1260	LocInfo.LastKill = VersionStack.size() - 1;
1261	LocInfo.LastKillValid = true;
1262	LocInfo.AR = MayAlias;
1263	}
1264
1265	// At this point, we should have corrected last kill and LowerBound to be
1266	// in bounds.
1267	assert(LocInfo.LowerBound < VersionStack.size() &&((LocInfo.LowerBound < VersionStack.size() && "Lower bound out of range" ) ? static_cast<void> (0) : __assert_fail ("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1268, __PRETTY_FUNCTION__))
1268	"Lower bound out of range")((LocInfo.LowerBound < VersionStack.size() && "Lower bound out of range" ) ? static_cast<void> (0) : __assert_fail ("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1268, __PRETTY_FUNCTION__));
1269	assert(LocInfo.LastKill < VersionStack.size() &&((LocInfo.LastKill < VersionStack.size() && "Last kill info out of range" ) ? static_cast<void> (0) : __assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1270, __PRETTY_FUNCTION__))
1270	"Last kill info out of range")((LocInfo.LastKill < VersionStack.size() && "Last kill info out of range" ) ? static_cast<void> (0) : __assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1270, __PRETTY_FUNCTION__));
1271	// In any case, the new upper bound is the top of the stack.
1272	unsigned long UpperBound = VersionStack.size() - 1;
1273
1274	if (UpperBound - LocInfo.LowerBound > MaxCheckLimit) {
1275	LLVM_DEBUG(dbgs() << "MemorySSA skipping optimization of " << MU << " ("do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "MemorySSA skipping optimization of " << MU << " (" << *(MU->getMemoryInst() ) << ")" << " because there are " << UpperBound - LocInfo.LowerBound << " stores to disambiguate\n"; } } while (false)
1276	<< (MU->getMemoryInst()) << ")"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "MemorySSA skipping optimization of " << MU << " (" << *(MU->getMemoryInst() ) << ")" << " because there are " << UpperBound - LocInfo.LowerBound << " stores to disambiguate\n"; } } while (false)
1277	<< " because there are "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "MemorySSA skipping optimization of " << MU << " (" << (MU->getMemoryInst() ) << ")" << " because there are " << UpperBound - LocInfo.LowerBound << " stores to disambiguate\n"; } } while (false)
1278	<< UpperBound - LocInfo.LowerBounddo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "MemorySSA skipping optimization of " << MU << " (" << (MU->getMemoryInst() ) << ")" << " because there are " << UpperBound - LocInfo.LowerBound << " stores to disambiguate\n"; } } while (false)
1279	<< " stores to disambiguate\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "MemorySSA skipping optimization of " << MU << " (" << (MU->getMemoryInst() ) << ")" << " because there are " << UpperBound - LocInfo.LowerBound << " stores to disambiguate\n"; } } while (false);
1280	// Because we did not walk, LastKill is no longer valid, as this may
1281	// have been a kill.
1282	LocInfo.LastKillValid = false;
1283	continue;
1284	}
1285	bool FoundClobberResult = false;
1286	while (UpperBound > LocInfo.LowerBound) {
1287	if (isa<MemoryPhi>(VersionStack[UpperBound])) {
1288	// For phis, use the walker, see where we ended up, go there
1289	Instruction *UseInst = MU->getMemoryInst();
1290	MemoryAccess *Result = Walker->getClobberingMemoryAccess(UseInst);
1291	// We are guaranteed to find it or something is wrong
1292	while (VersionStack[UpperBound] != Result) {
1293	assert(UpperBound != 0)((UpperBound != 0) ? static_cast<void> (0) : __assert_fail ("UpperBound != 0", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1293, __PRETTY_FUNCTION__));
1294	--UpperBound;
1295	}
1296	FoundClobberResult = true;
1297	break;
1298	}
1299
1300	MemoryDef *MD = cast<MemoryDef>(VersionStack[UpperBound]);
1301	// If the lifetime of the pointer ends at this instruction, it's live on
1302	// entry.
1303	if (!UseMLOC.IsCall && lifetimeEndsAt(MD, UseMLOC.getLoc(), *AA)) {
1304	// Reset UpperBound to liveOnEntryDef's place in the stack
1305	UpperBound = 0;
1306	FoundClobberResult = true;
1307	LocInfo.AR = MustAlias;
1308	break;
1309	}
1310	ClobberAlias CA = instructionClobbersQuery(MD, MU, UseMLOC, *AA);
1311	if (CA.IsClobber) {
1312	FoundClobberResult = true;
1313	LocInfo.AR = CA.AR;
1314	break;
1315	}
1316	--UpperBound;
1317	}
1318
1319	// Note: Phis always have AliasResult AR set to MayAlias ATM.
1320
1321	// At the end of this loop, UpperBound is either a clobber, or lower bound
1322	// PHI walking may cause it to be < LowerBound, and in fact, < LastKill.
1323	if (FoundClobberResult \|\| UpperBound < LocInfo.LastKill) {
1324	// We were last killed now by where we got to
1325	if (MSSA->isLiveOnEntryDef(VersionStack[UpperBound]))
1326	LocInfo.AR = None;
1327	MU->setDefiningAccess(VersionStack[UpperBound], true, LocInfo.AR);
1328	LocInfo.LastKill = UpperBound;
1329	} else {
1330	// Otherwise, we checked all the new ones, and now we know we can get to
1331	// LastKill.
1332	MU->setDefiningAccess(VersionStack[LocInfo.LastKill], true, LocInfo.AR);
1333	}
1334	LocInfo.LowerBound = VersionStack.size() - 1;
1335	LocInfo.LowerBoundBlock = BB;
1336	}
1337	}
1338
1339	/// Optimize uses to point to their actual clobbering definitions.
1340	void MemorySSA::OptimizeUses::optimizeUses() {
1341	SmallVector<MemoryAccess *, 16> VersionStack;
1342	DenseMap<MemoryLocOrCall, MemlocStackInfo> LocStackInfo;
1343	VersionStack.push_back(MSSA->getLiveOnEntryDef());
1344
1345	unsigned long StackEpoch = 1;
1346	unsigned long PopEpoch = 1;
1347	// We perform a non-recursive top-down dominator tree walk.
1348	for (const auto *DomNode : depth_first(DT->getRootNode()))
1349	optimizeUsesInBlock(DomNode->getBlock(), StackEpoch, PopEpoch, VersionStack,
1350	LocStackInfo);
1351	}
1352
1353	void MemorySSA::placePHINodes(
1354	const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks) {
1355	// Determine where our MemoryPhi's should go
1356	ForwardIDFCalculator IDFs(*DT);
1357	IDFs.setDefiningBlocks(DefiningBlocks);
1358	SmallVector<BasicBlock *, 32> IDFBlocks;
1359	IDFs.calculate(IDFBlocks);
1360
1361	// Now place MemoryPhi nodes.
1362	for (auto &BB : IDFBlocks)
1363	createMemoryPhi(BB);
1364	}
1365
1366	void MemorySSA::buildMemorySSA() {
1367	// We create an access to represent "live on entry", for things like
1368	// arguments or users of globals, where the memory they use is defined before
1369	// the beginning of the function. We do not actually insert it into the IR.
1370	// We do not define a live on exit for the immediate uses, and thus our
1371	// semantics do not imply that something with no immediate uses can simply
1372	// be removed.
1373	BasicBlock &StartingPoint = F.getEntryBlock();
1374	LiveOnEntryDef.reset(new MemoryDef(F.getContext(), nullptr, nullptr,
1375	&StartingPoint, NextID++));
1376
1377	// We maintain lists of memory accesses per-block, trading memory for time. We
1378	// could just look up the memory access for every possible instruction in the
1379	// stream.
1380	SmallPtrSet<BasicBlock *, 32> DefiningBlocks;
1381	// Go through each block, figure out where defs occur, and chain together all
1382	// the accesses.
1383	for (BasicBlock &B : F) {
1384	bool InsertIntoDef = false;
1385	AccessList *Accesses = nullptr;
1386	DefsList *Defs = nullptr;
1387	for (Instruction &I : B) {
1388	MemoryUseOrDef *MUD = createNewAccess(&I);
1389	if (!MUD)
1390	continue;
1391
1392	if (!Accesses)
1393	Accesses = getOrCreateAccessList(&B);
1394	Accesses->push_back(MUD);
1395	if (isa<MemoryDef>(MUD)) {
1396	InsertIntoDef = true;
1397	if (!Defs)
1398	Defs = getOrCreateDefsList(&B);
1399	Defs->push_back(*MUD);
1400	}
1401	}
1402	if (InsertIntoDef)
1403	DefiningBlocks.insert(&B);
1404	}
1405	placePHINodes(DefiningBlocks);
1406
1407	// Now do regular SSA renaming on the MemoryDef/MemoryUse. Visited will get
1408	// filled in with all blocks.
1409	SmallPtrSet<BasicBlock *, 16> Visited;
1410	renamePass(DT->getRootNode(), LiveOnEntryDef.get(), Visited);
1411
1412	CachingWalker *Walker = getWalkerImpl();
1413
1414	OptimizeUses(this, Walker, AA, DT).optimizeUses();
1415
1416	// Mark the uses in unreachable blocks as live on entry, so that they go
1417	// somewhere.
1418	for (auto &BB : F)
1419	if (!Visited.count(&BB))
1420	markUnreachableAsLiveOnEntry(&BB);
1421	}
1422
1423	MemorySSAWalker *MemorySSA::getWalker() { return getWalkerImpl(); }
1424
1425	MemorySSA::CachingWalker *MemorySSA::getWalkerImpl() {
1426	if (Walker)
1427	return Walker.get();
1428
1429	Walker = llvm::make_unique<CachingWalker>(this, AA, DT);
1430	return Walker.get();
1431	}
1432
1433	// This is a helper function used by the creation routines. It places NewAccess
1434	// into the access and defs lists for a given basic block, at the given
1435	// insertion point.
1436	void MemorySSA::insertIntoListsForBlock(MemoryAccess *NewAccess,
1437	const BasicBlock *BB,
1438	InsertionPlace Point) {
1439	auto *Accesses = getOrCreateAccessList(BB);
1440	if (Point == Beginning) {
1441	// If it's a phi node, it goes first, otherwise, it goes after any phi
1442	// nodes.
1443	if (isa<MemoryPhi>(NewAccess)) {
1444	Accesses->push_front(NewAccess);
1445	auto *Defs = getOrCreateDefsList(BB);
1446	Defs->push_front(*NewAccess);
1447	} else {
1448	auto AI = find_if_not(
1449	*Accesses, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
1450	Accesses->insert(AI, NewAccess);
1451	if (!isa<MemoryUse>(NewAccess)) {
1452	auto *Defs = getOrCreateDefsList(BB);
1453	auto DI = find_if_not(
1454	*Defs, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
1455	Defs->insert(DI, *NewAccess);
1456	}
1457	}
1458	} else {
1459	Accesses->push_back(NewAccess);
1460	if (!isa<MemoryUse>(NewAccess)) {
1461	auto *Defs = getOrCreateDefsList(BB);
1462	Defs->push_back(*NewAccess);
1463	}
1464	}
1465	BlockNumberingValid.erase(BB);
1466	}
1467
1468	void MemorySSA::insertIntoListsBefore(MemoryAccess What, const BasicBlock BB,
1469	AccessList::iterator InsertPt) {
1470	auto *Accesses = getWritableBlockAccesses(BB);
1471	bool WasEnd = InsertPt == Accesses->end();
1472	Accesses->insert(AccessList::iterator(InsertPt), What);
1473	if (!isa<MemoryUse>(What)) {
1474	auto *Defs = getOrCreateDefsList(BB);
1475	// If we got asked to insert at the end, we have an easy job, just shove it
1476	// at the end. If we got asked to insert before an existing def, we also get
1477	// an iterator. If we got asked to insert before a use, we have to hunt for
1478	// the next def.
1479	if (WasEnd) {
1480	Defs->push_back(*What);
1481	} else if (isa<MemoryDef>(InsertPt)) {
1482	Defs->insert(InsertPt->getDefsIterator(), *What);
1483	} else {
1484	while (InsertPt != Accesses->end() && !isa<MemoryDef>(InsertPt))
1485	++InsertPt;
1486	// Either we found a def, or we are inserting at the end
1487	if (InsertPt == Accesses->end())
1488	Defs->push_back(*What);
1489	else
1490	Defs->insert(InsertPt->getDefsIterator(), *What);
1491	}
1492	}
1493	BlockNumberingValid.erase(BB);
1494	}
1495
1496	void MemorySSA::prepareForMoveTo(MemoryAccess What, BasicBlock BB) {
1497	// Keep it in the lookup tables, remove from the lists
1498	removeFromLists(What, false);
1499
1500	// Note that moving should implicitly invalidate the optimized state of a
1501	// MemoryUse (and Phis can't be optimized). However, it doesn't do so for a
1502	// MemoryDef.
1503	if (auto *MD = dyn_cast<MemoryDef>(What))
1504	MD->resetOptimized();
1505	What->setBlock(BB);
1506	}
1507
1508	// Move What before Where in the IR. The end result is that What will belong to
1509	// the right lists and have the right Block set, but will not otherwise be
1510	// correct. It will not have the right defining access, and if it is a def,
1511	// things below it will not properly be updated.
1512	void MemorySSA::moveTo(MemoryUseOrDef What, BasicBlock BB,
1513	AccessList::iterator Where) {
1514	prepareForMoveTo(What, BB);
1515	insertIntoListsBefore(What, BB, Where);
1516	}
1517
1518	void MemorySSA::moveTo(MemoryAccess What, BasicBlock BB,
1519	InsertionPlace Point) {
1520	if (isa<MemoryPhi>(What)) {
1521	assert(Point == Beginning &&((Point == Beginning && "Can only move a Phi at the beginning of the block" ) ? static_cast<void> (0) : __assert_fail ("Point == Beginning && \"Can only move a Phi at the beginning of the block\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1522, __PRETTY_FUNCTION__))
1522	"Can only move a Phi at the beginning of the block")((Point == Beginning && "Can only move a Phi at the beginning of the block" ) ? static_cast<void> (0) : __assert_fail ("Point == Beginning && \"Can only move a Phi at the beginning of the block\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1522, __PRETTY_FUNCTION__));
1523	// Update lookup table entry
1524	ValueToMemoryAccess.erase(What->getBlock());
1525	bool Inserted = ValueToMemoryAccess.insert({BB, What}).second;
1526	(void)Inserted;
1527	assert(Inserted && "Cannot move a Phi to a block that already has one")((Inserted && "Cannot move a Phi to a block that already has one" ) ? static_cast<void> (0) : __assert_fail ("Inserted && \"Cannot move a Phi to a block that already has one\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1527, __PRETTY_FUNCTION__));
1528	}
1529
1530	prepareForMoveTo(What, BB);
1531	insertIntoListsForBlock(What, BB, Point);
1532	}
1533
1534	MemoryPhi MemorySSA::createMemoryPhi(BasicBlock BB) {
1535	assert(!getMemoryAccess(BB) && "MemoryPhi already exists for this BB")((!getMemoryAccess(BB) && "MemoryPhi already exists for this BB" ) ? static_cast<void> (0) : __assert_fail ("!getMemoryAccess(BB) && \"MemoryPhi already exists for this BB\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1535, __PRETTY_FUNCTION__));
1536	MemoryPhi *Phi = new MemoryPhi(BB->getContext(), BB, NextID++);
1537	// Phi's always are placed at the front of the block.
1538	insertIntoListsForBlock(Phi, BB, Beginning);
1539	ValueToMemoryAccess[BB] = Phi;
1540	return Phi;
1541	}
1542
1543	MemoryUseOrDef MemorySSA::createDefinedAccess(Instruction I,
1544	MemoryAccess *Definition,
1545	const MemoryUseOrDef *Template) {
1546	assert(!isa<PHINode>(I) && "Cannot create a defined access for a PHI")((!isa<PHINode>(I) && "Cannot create a defined access for a PHI" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(I) && \"Cannot create a defined access for a PHI\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1546, __PRETTY_FUNCTION__));
1547	MemoryUseOrDef *NewAccess = createNewAccess(I, Template);
1548	assert(((NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction" ) ? static_cast<void> (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1550, __PRETTY_FUNCTION__))
1549	NewAccess != nullptr &&((NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction" ) ? static_cast<void> (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1550, __PRETTY_FUNCTION__))
1550	"Tried to create a memory access for a non-memory touching instruction")((NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction" ) ? static_cast<void> (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1550, __PRETTY_FUNCTION__));
1551	NewAccess->setDefiningAccess(Definition);
1552	return NewAccess;
1553	}
1554
1555	// Return true if the instruction has ordering constraints.
1556	// Note specifically that this only considers stores and loads
1557	// because others are still considered ModRef by getModRefInfo.
1558	static inline bool isOrdered(const Instruction *I) {
1559	if (auto *SI = dyn_cast<StoreInst>(I)) {
1560	if (!SI->isUnordered())
1561	return true;
1562	} else if (auto *LI = dyn_cast<LoadInst>(I)) {
1563	if (!LI->isUnordered())
1564	return true;
1565	}
1566	return false;
1567	}
1568
1569	/// Helper function to create new memory accesses
1570	MemoryUseOrDef MemorySSA::createNewAccess(Instruction I,
1571	const MemoryUseOrDef *Template) {
1572	// The assume intrinsic has a control dependency which we model by claiming
1573	// that it writes arbitrarily. Ignore that fake memory dependency here.
1574	// FIXME: Replace this special casing with a more accurate modelling of
1575	// assume's control dependency.
1576	if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
1577	if (II->getIntrinsicID() == Intrinsic::assume)
1578	return nullptr;
1579
1580	bool Def, Use;
1581	if (Template) {
1582	Def = dyn_cast_or_null<MemoryDef>(Template) != nullptr;
1583	Use = dyn_cast_or_null<MemoryUse>(Template) != nullptr;
1584	#if !defined(NDEBUG)
1585	ModRefInfo ModRef = AA->getModRefInfo(I, None);
1586	bool DefCheck, UseCheck;
1587	DefCheck = isModSet(ModRef) \|\| isOrdered(I);
1588	UseCheck = isRefSet(ModRef);
1589	assert(Def == DefCheck && (Def \|\| Use == UseCheck) && "Invalid template")((Def == DefCheck && (Def \|\| Use == UseCheck) && "Invalid template") ? static_cast<void> (0) : __assert_fail ("Def == DefCheck && (Def \|\| Use == UseCheck) && \"Invalid template\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1589, __PRETTY_FUNCTION__));
1590	#endif
1591	} else {
1592	// Find out what affect this instruction has on memory.
1593	ModRefInfo ModRef = AA->getModRefInfo(I, None);
1594	// The isOrdered check is used to ensure that volatiles end up as defs
1595	// (atomics end up as ModRef right now anyway). Until we separate the
1596	// ordering chain from the memory chain, this enables people to see at least
1597	// some relative ordering to volatiles. Note that getClobberingMemoryAccess
1598	// will still give an answer that bypasses other volatile loads. TODO:
1599	// Separate memory aliasing and ordering into two different chains so that
1600	// we can precisely represent both "what memory will this read/write/is
1601	// clobbered by" and "what instructions can I move this past".
1602	Def = isModSet(ModRef) \|\| isOrdered(I);
1603	Use = isRefSet(ModRef);
1604	}
1605
1606	// It's possible for an instruction to not modify memory at all. During
1607	// construction, we ignore them.
1608	if (!Def && !Use)
1609	return nullptr;
1610
1611	MemoryUseOrDef *MUD;
1612	if (Def)
1613	MUD = new MemoryDef(I->getContext(), nullptr, I, I->getParent(), NextID++);
1614	else
1615	MUD = new MemoryUse(I->getContext(), nullptr, I, I->getParent());
1616	ValueToMemoryAccess[I] = MUD;
1617	return MUD;
1618	}
1619
1620	/// Returns true if \p Replacer dominates \p Replacee .
1621	bool MemorySSA::dominatesUse(const MemoryAccess *Replacer,
1622	const MemoryAccess *Replacee) const {
1623	if (isa<MemoryUseOrDef>(Replacee))
1624	return DT->dominates(Replacer->getBlock(), Replacee->getBlock());
1625	const auto *MP = cast<MemoryPhi>(Replacee);
1626	// For a phi node, the use occurs in the predecessor block of the phi node.
1627	// Since we may occur multiple times in the phi node, we have to check each
1628	// operand to ensure Replacer dominates each operand where Replacee occurs.
1629	for (const Use &Arg : MP->operands()) {
1630	if (Arg.get() != Replacee &&
1631	!DT->dominates(Replacer->getBlock(), MP->getIncomingBlock(Arg)))
1632	return false;
1633	}
1634	return true;
1635	}
1636
1637	/// Properly remove \p MA from all of MemorySSA's lookup tables.
1638	void MemorySSA::removeFromLookups(MemoryAccess *MA) {
1639	assert(MA->use_empty() &&((MA->use_empty() && "Trying to remove memory access that still has uses" ) ? static_cast<void> (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1640, __PRETTY_FUNCTION__))
1640	"Trying to remove memory access that still has uses")((MA->use_empty() && "Trying to remove memory access that still has uses" ) ? static_cast<void> (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1640, __PRETTY_FUNCTION__));
1641	BlockNumbering.erase(MA);
1642	if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
1643	MUD->setDefiningAccess(nullptr);
1644	// Invalidate our walker's cache if necessary
1645	if (!isa<MemoryUse>(MA))
1646	Walker->invalidateInfo(MA);
1647
1648	Value *MemoryInst;
1649	if (const auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
1650	MemoryInst = MUD->getMemoryInst();
1651	else
1652	MemoryInst = MA->getBlock();
1653
1654	auto VMA = ValueToMemoryAccess.find(MemoryInst);
1655	if (VMA->second == MA)
1656	ValueToMemoryAccess.erase(VMA);
1657	}
1658
1659	/// Properly remove \p MA from all of MemorySSA's lists.
1660	///
1661	/// Because of the way the intrusive list and use lists work, it is important to
1662	/// do removal in the right order.
1663	/// ShouldDelete defaults to true, and will cause the memory access to also be
1664	/// deleted, not just removed.
1665	void MemorySSA::removeFromLists(MemoryAccess *MA, bool ShouldDelete) {
1666	BasicBlock *BB = MA->getBlock();
1667	// The access list owns the reference, so we erase it from the non-owning list
1668	// first.
1669	if (!isa<MemoryUse>(MA)) {
1670	auto DefsIt = PerBlockDefs.find(BB);
1671	std::unique_ptr<DefsList> &Defs = DefsIt->second;
1672	Defs->remove(*MA);
1673	if (Defs->empty())
1674	PerBlockDefs.erase(DefsIt);
1675	}
1676
1677	// The erase call here will delete it. If we don't want it deleted, we call
1678	// remove instead.
1679	auto AccessIt = PerBlockAccesses.find(BB);
1680	std::unique_ptr<AccessList> &Accesses = AccessIt->second;
1681	if (ShouldDelete)
1682	Accesses->erase(MA);
1683	else
1684	Accesses->remove(MA);
1685
1686	if (Accesses->empty()) {
1687	PerBlockAccesses.erase(AccessIt);
1688	BlockNumberingValid.erase(BB);
1689	}
1690	}
1691
1692	void MemorySSA::print(raw_ostream &OS) const {
1693	MemorySSAAnnotatedWriter Writer(this);
1694	F.print(OS, &Writer);
1695	}
1696
1697	#if !defined(NDEBUG) \|\| defined(LLVM_ENABLE_DUMP)
1698	LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void MemorySSA::dump() const { print(dbgs()); }
1699	#endif
1700
1701	void MemorySSA::verifyMemorySSA() const {
1702	verifyDefUses(F);
1703	verifyDomination(F);
1704	verifyOrdering(F);
1705	verifyDominationNumbers(F);
1706	Walker->verify(this);
1707	verifyClobberSanity(F);
1708	}
1709
1710	/// Check sanity of the clobbering instruction for access MA.
1711	void MemorySSA::checkClobberSanityAccess(const MemoryAccess *MA) const {
1712	if (const auto *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
1713	if (!MUD->isOptimized())
1714	return;
1715	auto *I = MUD->getMemoryInst();
1716	auto Loc = MemoryLocation::getOrNone(I);
1717	if (Loc == None)
1718	return;
1719	auto *Clobber = MUD->getOptimized();
1720	UpwardsMemoryQuery Q(I, MUD);
1721	checkClobberSanity(MUD, Clobber, Loc, this, Q, *AA, true);
1722	}
1723	}
1724
1725	void MemorySSA::verifyClobberSanity(const Function &F) const {
1726	#if !defined(NDEBUG) && defined(EXPENSIVE_CHECKS)
1727	for (const BasicBlock &BB : F) {
1728	const AccessList *Accesses = getBlockAccesses(&BB);
1729	if (!Accesses)
1730	continue;
1731	for (const MemoryAccess &MA : *Accesses)
1732	checkClobberSanityAccess(&MA);
1733	}
1734	#endif
1735	}
1736
1737	/// Verify that all of the blocks we believe to have valid domination numbers
1738	/// actually have valid domination numbers.
1739	void MemorySSA::verifyDominationNumbers(const Function &F) const {
1740	#ifndef NDEBUG
1741	if (BlockNumberingValid.empty())
1742	return;
1743
1744	SmallPtrSet<const BasicBlock *, 16> ValidBlocks = BlockNumberingValid;
1745	for (const BasicBlock &BB : F) {
1746	if (!ValidBlocks.count(&BB))
1747	continue;
1748
1749	ValidBlocks.erase(&BB);
1750
1751	const AccessList *Accesses = getBlockAccesses(&BB);
1752	// It's correct to say an empty block has valid numbering.
1753	if (!Accesses)
1754	continue;
1755
1756	// Block numbering starts at 1.
1757	unsigned long LastNumber = 0;
1758	for (const MemoryAccess &MA : *Accesses) {
1759	auto ThisNumberIter = BlockNumbering.find(&MA);
1760	assert(ThisNumberIter != BlockNumbering.end() &&((ThisNumberIter != BlockNumbering.end() && "MemoryAccess has no domination number in a valid block!" ) ? static_cast<void> (0) : __assert_fail ("ThisNumberIter != BlockNumbering.end() && \"MemoryAccess has no domination number in a valid block!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1761, __PRETTY_FUNCTION__))
1761	"MemoryAccess has no domination number in a valid block!")((ThisNumberIter != BlockNumbering.end() && "MemoryAccess has no domination number in a valid block!" ) ? static_cast<void> (0) : __assert_fail ("ThisNumberIter != BlockNumbering.end() && \"MemoryAccess has no domination number in a valid block!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1761, __PRETTY_FUNCTION__));
1762
1763	unsigned long ThisNumber = ThisNumberIter->second;
1764	assert(ThisNumber > LastNumber &&((ThisNumber > LastNumber && "Domination numbers should be strictly increasing!" ) ? static_cast<void> (0) : __assert_fail ("ThisNumber > LastNumber && \"Domination numbers should be strictly increasing!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1765, __PRETTY_FUNCTION__))
1765	"Domination numbers should be strictly increasing!")((ThisNumber > LastNumber && "Domination numbers should be strictly increasing!" ) ? static_cast<void> (0) : __assert_fail ("ThisNumber > LastNumber && \"Domination numbers should be strictly increasing!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1765, __PRETTY_FUNCTION__));
1766	LastNumber = ThisNumber;
1767	}
1768	}
1769
1770	assert(ValidBlocks.empty() &&((ValidBlocks.empty() && "All valid BasicBlocks should exist in F -- dangling pointers?" ) ? static_cast<void> (0) : __assert_fail ("ValidBlocks.empty() && \"All valid BasicBlocks should exist in F -- dangling pointers?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1771, __PRETTY_FUNCTION__))
1771	"All valid BasicBlocks should exist in F -- dangling pointers?")((ValidBlocks.empty() && "All valid BasicBlocks should exist in F -- dangling pointers?" ) ? static_cast<void> (0) : __assert_fail ("ValidBlocks.empty() && \"All valid BasicBlocks should exist in F -- dangling pointers?\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1771, __PRETTY_FUNCTION__));
1772	#endif
1773	}
1774
1775	/// Verify that the order and existence of MemoryAccesses matches the
1776	/// order and existence of memory affecting instructions.
1777	void MemorySSA::verifyOrdering(Function &F) const {
1778	#ifndef NDEBUG
1779	// Walk all the blocks, comparing what the lookups think and what the access
1780	// lists think, as well as the order in the blocks vs the order in the access
1781	// lists.
1782	SmallVector<MemoryAccess *, 32> ActualAccesses;
1783	SmallVector<MemoryAccess *, 32> ActualDefs;
1784	for (BasicBlock &B : F) {
1785	const AccessList *AL = getBlockAccesses(&B);
1786	const auto *DL = getBlockDefs(&B);
1787	MemoryAccess *Phi = getMemoryAccess(&B);
1788	if (Phi) {
1789	ActualAccesses.push_back(Phi);
1790	ActualDefs.push_back(Phi);
1791	}
1792
1793	for (Instruction &I : B) {
1794	MemoryAccess *MA = getMemoryAccess(&I);
1795	assert((!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) &&(((!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && "We have memory affecting instructions " "in this block but they are not in the " "access list or defs list") ? static_cast<void> (0) : __assert_fail ("(!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1798, __PRETTY_FUNCTION__))
1796	"We have memory affecting instructions "(((!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && "We have memory affecting instructions " "in this block but they are not in the " "access list or defs list") ? static_cast<void> (0) : __assert_fail ("(!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1798, __PRETTY_FUNCTION__))
1797	"in this block but they are not in the "(((!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && "We have memory affecting instructions " "in this block but they are not in the " "access list or defs list") ? static_cast<void> (0) : __assert_fail ("(!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1798, __PRETTY_FUNCTION__))
1798	"access list or defs list")(((!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && "We have memory affecting instructions " "in this block but they are not in the " "access list or defs list") ? static_cast<void> (0) : __assert_fail ("(!MA \|\| (AL && (isa<MemoryUse>(MA) \|\| DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1798, __PRETTY_FUNCTION__));
1799	if (MA) {
1800	ActualAccesses.push_back(MA);
1801	if (isa<MemoryDef>(MA))
1802	ActualDefs.push_back(MA);
1803	}
1804	}
1805	// Either we hit the assert, really have no accesses, or we have both
1806	// accesses and an access list.
1807	// Same with defs.
1808	if (!AL && !DL)
1809	continue;
1810	assert(AL->size() == ActualAccesses.size() &&((AL->size() == ActualAccesses.size() && "We don't have the same number of accesses in the block as on the " "access list") ? static_cast<void> (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1812, __PRETTY_FUNCTION__))
1811	"We don't have the same number of accesses in the block as on the "((AL->size() == ActualAccesses.size() && "We don't have the same number of accesses in the block as on the " "access list") ? static_cast<void> (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1812, __PRETTY_FUNCTION__))
1812	"access list")((AL->size() == ActualAccesses.size() && "We don't have the same number of accesses in the block as on the " "access list") ? static_cast<void> (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1812, __PRETTY_FUNCTION__));
1813	assert((DL \|\| ActualDefs.size() == 0) &&(((DL \|\| ActualDefs.size() == 0) && "Either we should have a defs list, or we should have no defs" ) ? static_cast<void> (0) : __assert_fail ("(DL \|\| ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1814, __PRETTY_FUNCTION__))
1814	"Either we should have a defs list, or we should have no defs")(((DL \|\| ActualDefs.size() == 0) && "Either we should have a defs list, or we should have no defs" ) ? static_cast<void> (0) : __assert_fail ("(DL \|\| ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1814, __PRETTY_FUNCTION__));
1815	assert((!DL \|\| DL->size() == ActualDefs.size()) &&(((!DL \|\| DL->size() == ActualDefs.size()) && "We don't have the same number of defs in the block as on the " "def list") ? static_cast<void> (0) : __assert_fail ("(!DL \|\| DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1817, __PRETTY_FUNCTION__))
1816	"We don't have the same number of defs in the block as on the "(((!DL \|\| DL->size() == ActualDefs.size()) && "We don't have the same number of defs in the block as on the " "def list") ? static_cast<void> (0) : __assert_fail ("(!DL \|\| DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1817, __PRETTY_FUNCTION__))
1817	"def list")(((!DL \|\| DL->size() == ActualDefs.size()) && "We don't have the same number of defs in the block as on the " "def list") ? static_cast<void> (0) : __assert_fail ("(!DL \|\| DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1817, __PRETTY_FUNCTION__));
1818	auto ALI = AL->begin();
1819	auto AAI = ActualAccesses.begin();
1820	while (ALI != AL->end() && AAI != ActualAccesses.end()) {
1821	assert(&ALI == AAI && "Not the same accesses in the same order")((&ALI == AAI && "Not the same accesses in the same order" ) ? static_cast<void> (0) : __assert_fail ("&ALI == AAI && \"Not the same accesses in the same order\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1821, __PRETTY_FUNCTION__));
1822	++ALI;
1823	++AAI;
1824	}
1825	ActualAccesses.clear();
1826	if (DL) {
1827	auto DLI = DL->begin();
1828	auto ADI = ActualDefs.begin();
1829	while (DLI != DL->end() && ADI != ActualDefs.end()) {
1830	assert(&DLI == ADI && "Not the same defs in the same order")((&DLI == ADI && "Not the same defs in the same order" ) ? static_cast<void> (0) : __assert_fail ("&DLI == ADI && \"Not the same defs in the same order\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1830, __PRETTY_FUNCTION__));
1831	++DLI;
1832	++ADI;
1833	}
1834	}
1835	ActualDefs.clear();
1836	}
1837	#endif
1838	}
1839
1840	/// Verify the domination properties of MemorySSA by checking that each
1841	/// definition dominates all of its uses.
1842	void MemorySSA::verifyDomination(Function &F) const {
1843	#ifndef NDEBUG
1844	for (BasicBlock &B : F) {
1845	// Phi nodes are attached to basic blocks
1846	if (MemoryPhi *MP = getMemoryAccess(&B))
1847	for (const Use &U : MP->uses())
1848	assert(dominates(MP, U) && "Memory PHI does not dominate it's uses")((dominates(MP, U) && "Memory PHI does not dominate it's uses" ) ? static_cast<void> (0) : __assert_fail ("dominates(MP, U) && \"Memory PHI does not dominate it's uses\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1848, __PRETTY_FUNCTION__));
1849
1850	for (Instruction &I : B) {
1851	MemoryAccess *MD = dyn_cast_or_null<MemoryDef>(getMemoryAccess(&I));
1852	if (!MD)
1853	continue;
1854
1855	for (const Use &U : MD->uses())
1856	assert(dominates(MD, U) && "Memory Def does not dominate it's uses")((dominates(MD, U) && "Memory Def does not dominate it's uses" ) ? static_cast<void> (0) : __assert_fail ("dominates(MD, U) && \"Memory Def does not dominate it's uses\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1856, __PRETTY_FUNCTION__));
1857	}
1858	}
1859	#endif
1860	}
1861
1862	/// Verify the def-use lists in MemorySSA, by verifying that \p Use
1863	/// appears in the use list of \p Def.
1864	void MemorySSA::verifyUseInDefs(MemoryAccess Def, MemoryAccess Use) const {
1865	#ifndef NDEBUG
1866	// The live on entry use may cause us to get a NULL def here
1867	if (!Def)
1868	assert(isLiveOnEntryDef(Use) &&((isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def" ) ? static_cast<void> (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1869, __PRETTY_FUNCTION__))
1869	"Null def but use not point to live on entry def")((isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def" ) ? static_cast<void> (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1869, __PRETTY_FUNCTION__));
1870	else
1871	assert(is_contained(Def->users(), Use) &&((is_contained(Def->users(), Use) && "Did not find use in def's use list" ) ? static_cast<void> (0) : __assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1872, __PRETTY_FUNCTION__))
1872	"Did not find use in def's use list")((is_contained(Def->users(), Use) && "Did not find use in def's use list" ) ? static_cast<void> (0) : __assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1872, __PRETTY_FUNCTION__));
1873	#endif
1874	}
1875
1876	/// Verify the immediate use information, by walking all the memory
1877	/// accesses and verifying that, for each use, it appears in the
1878	/// appropriate def's use list
1879	void MemorySSA::verifyDefUses(Function &F) const {
1880	#ifndef NDEBUG
1881	for (BasicBlock &B : F) {
1882	// Phi nodes are attached to basic blocks
1883	if (MemoryPhi *Phi = getMemoryAccess(&B)) {
1884	assert(Phi->getNumOperands() == static_cast<unsigned>(std::distance(((Phi->getNumOperands() == static_cast<unsigned>(std ::distance( pred_begin(&B), pred_end(&B))) && "Incomplete MemoryPhi Node") ? static_cast<void> (0) : __assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1886, __PRETTY_FUNCTION__))
1885	pred_begin(&B), pred_end(&B))) &&((Phi->getNumOperands() == static_cast<unsigned>(std ::distance( pred_begin(&B), pred_end(&B))) && "Incomplete MemoryPhi Node") ? static_cast<void> (0) : __assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1886, __PRETTY_FUNCTION__))
1886	"Incomplete MemoryPhi Node")((Phi->getNumOperands() == static_cast<unsigned>(std ::distance( pred_begin(&B), pred_end(&B))) && "Incomplete MemoryPhi Node") ? static_cast<void> (0) : __assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1886, __PRETTY_FUNCTION__));
1887	for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I) {
1888	verifyUseInDefs(Phi->getIncomingValue(I), Phi);
1889	assert(find(predecessors(&B), Phi->getIncomingBlock(I)) !=((find(predecessors(&B), Phi->getIncomingBlock(I)) != pred_end (&B) && "Incoming phi block not a block predecessor" ) ? static_cast<void> (0) : __assert_fail ("find(predecessors(&B), Phi->getIncomingBlock(I)) != pred_end(&B) && \"Incoming phi block not a block predecessor\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1891, __PRETTY_FUNCTION__))
1890	pred_end(&B) &&((find(predecessors(&B), Phi->getIncomingBlock(I)) != pred_end (&B) && "Incoming phi block not a block predecessor" ) ? static_cast<void> (0) : __assert_fail ("find(predecessors(&B), Phi->getIncomingBlock(I)) != pred_end(&B) && \"Incoming phi block not a block predecessor\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1891, __PRETTY_FUNCTION__))
1891	"Incoming phi block not a block predecessor")((find(predecessors(&B), Phi->getIncomingBlock(I)) != pred_end (&B) && "Incoming phi block not a block predecessor" ) ? static_cast<void> (0) : __assert_fail ("find(predecessors(&B), Phi->getIncomingBlock(I)) != pred_end(&B) && \"Incoming phi block not a block predecessor\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1891, __PRETTY_FUNCTION__));
1892	}
1893	}
1894
1895	for (Instruction &I : B) {
1896	if (MemoryUseOrDef *MA = getMemoryAccess(&I)) {
1897	verifyUseInDefs(MA->getDefiningAccess(), MA);
1898	}
1899	}
1900	}
1901	#endif
1902	}
1903
1904	/// Perform a local numbering on blocks so that instruction ordering can be
1905	/// determined in constant time.
1906	/// TODO: We currently just number in order. If we numbered by N, we could
1907	/// allow at least N-1 sequences of insertBefore or insertAfter (and at least
1908	/// log2(N) sequences of mixed before and after) without needing to invalidate
1909	/// the numbering.
1910	void MemorySSA::renumberBlock(const BasicBlock *B) const {
1911	// The pre-increment ensures the numbers really start at 1.
1912	unsigned long CurrentNumber = 0;
1913	const AccessList *AL = getBlockAccesses(B);
1914	assert(AL != nullptr && "Asking to renumber an empty block")((AL != nullptr && "Asking to renumber an empty block" ) ? static_cast<void> (0) : __assert_fail ("AL != nullptr && \"Asking to renumber an empty block\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1914, __PRETTY_FUNCTION__));
1915	for (const auto &I : *AL)
1916	BlockNumbering[&I] = ++CurrentNumber;
1917	BlockNumberingValid.insert(B);
1918	}
1919
1920	/// Determine, for two memory accesses in the same block,
1921	/// whether \p Dominator dominates \p Dominatee.
1922	/// \returns True if \p Dominator dominates \p Dominatee.
1923	bool MemorySSA::locallyDominates(const MemoryAccess *Dominator,
1924	const MemoryAccess *Dominatee) const {
1925	const BasicBlock *DominatorBlock = Dominator->getBlock();
1926
1927	assert((DominatorBlock == Dominatee->getBlock()) &&(((DominatorBlock == Dominatee->getBlock()) && "Asking for local domination when accesses are in different blocks!" ) ? static_cast<void> (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1928, __PRETTY_FUNCTION__))
1928	"Asking for local domination when accesses are in different blocks!")(((DominatorBlock == Dominatee->getBlock()) && "Asking for local domination when accesses are in different blocks!" ) ? static_cast<void> (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1928, __PRETTY_FUNCTION__));
1929	// A node dominates itself.
1930	if (Dominatee == Dominator)
1931	return true;
1932
1933	// When Dominatee is defined on function entry, it is not dominated by another
1934	// memory access.
1935	if (isLiveOnEntryDef(Dominatee))
1936	return false;
1937
1938	// When Dominator is defined on function entry, it dominates the other memory
1939	// access.
1940	if (isLiveOnEntryDef(Dominator))
1941	return true;
1942
1943	if (!BlockNumberingValid.count(DominatorBlock))
1944	renumberBlock(DominatorBlock);
1945
1946	unsigned long DominatorNum = BlockNumbering.lookup(Dominator);
1947	// All numbers start with 1
1948	assert(DominatorNum != 0 && "Block was not numbered properly")((DominatorNum != 0 && "Block was not numbered properly" ) ? static_cast<void> (0) : __assert_fail ("DominatorNum != 0 && \"Block was not numbered properly\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1948, __PRETTY_FUNCTION__));
1949	unsigned long DominateeNum = BlockNumbering.lookup(Dominatee);
1950	assert(DominateeNum != 0 && "Block was not numbered properly")((DominateeNum != 0 && "Block was not numbered properly" ) ? static_cast<void> (0) : __assert_fail ("DominateeNum != 0 && \"Block was not numbered properly\"" , "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1950, __PRETTY_FUNCTION__));
1951	return DominatorNum < DominateeNum;
1952	}
1953
1954	bool MemorySSA::dominates(const MemoryAccess *Dominator,
1955	const MemoryAccess *Dominatee) const {
1956	if (Dominator == Dominatee)
1957	return true;
1958
1959	if (isLiveOnEntryDef(Dominatee))
1960	return false;
1961
1962	if (Dominator->getBlock() != Dominatee->getBlock())
1963	return DT->dominates(Dominator->getBlock(), Dominatee->getBlock());
1964	return locallyDominates(Dominator, Dominatee);
1965	}
1966
1967	bool MemorySSA::dominates(const MemoryAccess *Dominator,
1968	const Use &Dominatee) const {
1969	if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Dominatee.getUser())) {
1970	BasicBlock *UseBB = MP->getIncomingBlock(Dominatee);
1971	// The def must dominate the incoming block of the phi.
1972	if (UseBB != Dominator->getBlock())
1973	return DT->dominates(Dominator->getBlock(), UseBB);
1974	// If the UseBB and the DefBB are the same, compare locally.
1975	return locallyDominates(Dominator, cast<MemoryAccess>(Dominatee));
1976	}
1977	// If it's not a PHI node use, the normal dominates can already handle it.
1978	return dominates(Dominator, cast<MemoryAccess>(Dominatee.getUser()));
1979	}
1980
1981	const static char LiveOnEntryStr[] = "liveOnEntry";
1982
1983	void MemoryAccess::print(raw_ostream &OS) const {
1984	switch (getValueID()) {
1985	case MemoryPhiVal: return static_cast<const MemoryPhi *>(this)->print(OS);
1986	case MemoryDefVal: return static_cast<const MemoryDef *>(this)->print(OS);
1987	case MemoryUseVal: return static_cast<const MemoryUse *>(this)->print(OS);
1988	}
1989	llvm_unreachable("invalid value id")::llvm::llvm_unreachable_internal("invalid value id", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/MemorySSA.cpp" , 1989);
1990	}
1991
1992	void MemoryDef::print(raw_ostream &OS) const {
1993	MemoryAccess *UO = getDefiningAccess();
1994
1995	auto printID = [&OS](MemoryAccess *A) {
1996	if (A && A->getID())
1997	OS << A->getID();
1998	else
1999	OS << LiveOnEntryStr;
2000	};
2001
2002	OS << getID() << " = MemoryDef(";
2003	printID(UO);
2004	OS << ")";
2005
2006	if (isOptimized()) {
2007	OS << "->";
2008	printID(getOptimized());
2009
2010	if (Optional<AliasResult> AR = getOptimizedAccessType())
2011	OS << " " << *AR;
2012	}
2013	}
2014
2015	void MemoryPhi::print(raw_ostream &OS) const {
2016	bool First = true;
2017	OS << getID() << " = MemoryPhi(";
2018	for (const auto &Op : operands()) {
2019	BasicBlock *BB = getIncomingBlock(Op);
2020	MemoryAccess *MA = cast<MemoryAccess>(Op);
2021	if (!First)
2022	OS << ',';
2023	else
2024	First = false;
2025
2026	OS << '{';
2027	if (BB->hasName())
2028	OS << BB->getName();
2029	else
2030	BB->printAsOperand(OS, false);
2031	OS << ',';
2032	if (unsigned ID = MA->getID())
2033	OS << ID;
2034	else
2035	OS << LiveOnEntryStr;
2036	OS << '}';
2037	}
2038	OS << ')';
2039	}
2040
2041	void MemoryUse::print(raw_ostream &OS) const {
2042	MemoryAccess *UO = getDefiningAccess();
2043	OS << "MemoryUse(";
2044	if (UO && UO->getID())
2045	OS << UO->getID();
2046	else
2047	OS << LiveOnEntryStr;
2048	OS << ')';
2049
2050	if (Optional<AliasResult> AR = getOptimizedAccessType())
2051	OS << " " << *AR;
2052	}
2053
2054	void MemoryAccess::dump() const {
2055	// Cannot completely remove virtual function even in release mode.
2056	#if !defined(NDEBUG) \|\| defined(LLVM_ENABLE_DUMP)
2057	print(dbgs());
2058	dbgs() << "\n";
2059	#endif
2060	}
2061
2062	char MemorySSAPrinterLegacyPass::ID = 0;
2063
2064	MemorySSAPrinterLegacyPass::MemorySSAPrinterLegacyPass() : FunctionPass(ID) {
2065	initializeMemorySSAPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
2066	}
2067
2068	void MemorySSAPrinterLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
2069	AU.setPreservesAll();
2070	AU.addRequired<MemorySSAWrapperPass>();
2071	}
2072
2073	bool MemorySSAPrinterLegacyPass::runOnFunction(Function &F) {
2074	auto &MSSA = getAnalysis<MemorySSAWrapperPass>().getMSSA();
2075	MSSA.print(dbgs());
2076	if (VerifyMemorySSA)
2077	MSSA.verifyMemorySSA();
2078	return false;
2079	}
2080
2081	AnalysisKey MemorySSAAnalysis::Key;
2082
2083	MemorySSAAnalysis::Result MemorySSAAnalysis::run(Function &F,
2084	FunctionAnalysisManager &AM) {
2085	auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
2086	auto &AA = AM.getResult<AAManager>(F);
2087	return MemorySSAAnalysis::Result(llvm::make_unique<MemorySSA>(F, &AA, &DT));
2088	}
2089
2090	PreservedAnalyses MemorySSAPrinterPass::run(Function &F,
2091	FunctionAnalysisManager &AM) {
2092	OS << "MemorySSA for function: " << F.getName() << "\n";
2093	AM.getResult<MemorySSAAnalysis>(F).getMSSA().print(OS);
2094
2095	return PreservedAnalyses::all();
2096	}
2097
2098	PreservedAnalyses MemorySSAVerifierPass::run(Function &F,
2099	FunctionAnalysisManager &AM) {
2100	AM.getResult<MemorySSAAnalysis>(F).getMSSA().verifyMemorySSA();
2101
2102	return PreservedAnalyses::all();
2103	}
2104
2105	char MemorySSAWrapperPass::ID = 0;
2106
2107	MemorySSAWrapperPass::MemorySSAWrapperPass() : FunctionPass(ID) {
2108	initializeMemorySSAWrapperPassPass(*PassRegistry::getPassRegistry());
2109	}
2110
2111	void MemorySSAWrapperPass::releaseMemory() { MSSA.reset(); }
2112
2113	void MemorySSAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
2114	AU.setPreservesAll();
2115	AU.addRequiredTransitive<DominatorTreeWrapperPass>();
2116	AU.addRequiredTransitive<AAResultsWrapperPass>();
2117	}
2118
2119	bool MemorySSAWrapperPass::runOnFunction(Function &F) {
2120	auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
2121	auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
2122	MSSA.reset(new MemorySSA(F, &AA, &DT));
2123	return false;
2124	}
2125
2126	void MemorySSAWrapperPass::verifyAnalysis() const { MSSA->verifyMemorySSA(); }
2127
2128	void MemorySSAWrapperPass::print(raw_ostream &OS, const Module *M) const {
2129	MSSA->print(OS);
2130	}
2131
2132	MemorySSAWalker::MemorySSAWalker(MemorySSA *M) : MSSA(M) {}
2133
2134	MemorySSA::CachingWalker::CachingWalker(MemorySSA M, AliasAnalysis A,
2135	DominatorTree *D)
2136	: MemorySSAWalker(M), Walker(M, A, *D) {}
2137
2138	void MemorySSA::CachingWalker::invalidateInfo(MemoryAccess *MA) {
2139	if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
2140	MUD->resetOptimized();
2141	}
2142
2143	/// Walk the use-def chains starting at \p MA and find
2144	/// the MemoryAccess that actually clobbers Loc.
2145	///
2146	/// \returns our clobbering memory access
2147	MemoryAccess *MemorySSA::CachingWalker::getClobberingMemoryAccess(
2148	MemoryAccess *StartingAccess, UpwardsMemoryQuery &Q) {
2149	return Walker.findClobber(StartingAccess, Q);
2150	}
2151
2152	MemoryAccess *MemorySSA::CachingWalker::getClobberingMemoryAccess(
2153	MemoryAccess *StartingAccess, const MemoryLocation &Loc) {
2154	if (isa<MemoryPhi>(StartingAccess))
2155	return StartingAccess;
2156
2157	auto *StartingUseOrDef = cast<MemoryUseOrDef>(StartingAccess);
2158	if (MSSA->isLiveOnEntryDef(StartingUseOrDef))
2159	return StartingUseOrDef;
2160
2161	Instruction *I = StartingUseOrDef->getMemoryInst();
2162
2163	// Conservatively, fences are always clobbers, so don't perform the walk if we
2164	// hit a fence.
2165	if (!ImmutableCallSite(I) && I->isFenceLike())
2166	return StartingUseOrDef;
2167
2168	UpwardsMemoryQuery Q;
2169	Q.OriginalAccess = StartingUseOrDef;
2170	Q.StartingLoc = Loc;
2171	Q.Inst = I;
2172	Q.IsCall = false;
2173
2174	// Unlike the other function, do not walk to the def of a def, because we are
2175	// handed something we already believe is the clobbering access.
2176	MemoryAccess *DefiningAccess = isa<MemoryUse>(StartingUseOrDef)
2177	? StartingUseOrDef->getDefiningAccess()
2178	: StartingUseOrDef;
2179
2180	MemoryAccess *Clobber = getClobberingMemoryAccess(DefiningAccess, Q);
2181	LLVM_DEBUG(dbgs() << "Starting Memory SSA clobber for " << I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "Starting Memory SSA clobber for " << I << " is "; } } while (false);
2182	LLVM_DEBUG(dbgs() << StartingUseOrDef << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << StartingUseOrDef << "\n" ; } } while (false);
2183	LLVM_DEBUG(dbgs() << "Final Memory SSA clobber for " << I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "Final Memory SSA clobber for " << I << " is "; } } while (false);
2184	LLVM_DEBUG(dbgs() << Clobber << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << Clobber << "\n"; } } while (false);
2185	return Clobber;
2186	}
2187
2188	MemoryAccess *
2189	MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
2190	auto *StartingAccess = dyn_cast<MemoryUseOrDef>(MA);
2191	// If this is a MemoryPhi, we can't do anything.
2192	if (!StartingAccess)
2193	return MA;
2194
2195	// If this is an already optimized use or def, return the optimized result.
2196	// Note: Currently, we store the optimized def result in a separate field,
2197	// since we can't use the defining access.
2198	if (StartingAccess->isOptimized())
2199	return StartingAccess->getOptimized();
2200
2201	const Instruction *I = StartingAccess->getMemoryInst();
2202	// We can't sanely do anything with a fence, since they conservatively clobber
2203	// all memory, and have no locations to get pointers from to try to
2204	// disambiguate.
2205	if (!ImmutableCallSite(I) && I->isFenceLike())
2206	return StartingAccess;
2207
2208	UpwardsMemoryQuery Q(I, StartingAccess);
2209
2210	if (isUseTriviallyOptimizableToLiveOnEntry(*MSSA->AA, I)) {
2211	MemoryAccess *LiveOnEntry = MSSA->getLiveOnEntryDef();
2212	StartingAccess->setOptimized(LiveOnEntry);
2213	StartingAccess->setOptimizedAccessType(None);
2214	return LiveOnEntry;
2215	}
2216
2217	// Start with the thing we already think clobbers this location
2218	MemoryAccess *DefiningAccess = StartingAccess->getDefiningAccess();
2219
2220	// At this point, DefiningAccess may be the live on entry def.
2221	// If it is, we will not get a better result.
2222	if (MSSA->isLiveOnEntryDef(DefiningAccess)) {
2223	StartingAccess->setOptimized(DefiningAccess);
2224	StartingAccess->setOptimizedAccessType(None);
2225	return DefiningAccess;
2226	}
2227
2228	MemoryAccess *Result = getClobberingMemoryAccess(DefiningAccess, Q);
2229	LLVM_DEBUG(dbgs() << "Starting Memory SSA clobber for " << I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "Starting Memory SSA clobber for " << I << " is "; } } while (false);
2230	LLVM_DEBUG(dbgs() << DefiningAccess << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << DefiningAccess << "\n" ; } } while (false);
2231	LLVM_DEBUG(dbgs() << "Final Memory SSA clobber for " << I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << "Final Memory SSA clobber for " << I << " is "; } } while (false);
2232	LLVM_DEBUG(dbgs() << Result << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("memoryssa")) { dbgs() << Result << "\n"; } } while (false);
2233
2234	StartingAccess->setOptimized(Result);
2235	if (MSSA->isLiveOnEntryDef(Result))
2236	StartingAccess->setOptimizedAccessType(None);
2237	else if (Q.AR == MustAlias)
2238	StartingAccess->setOptimizedAccessType(MustAlias);
2239
2240	return Result;
2241	}
2242
2243	MemoryAccess *
2244	DoNothingMemorySSAWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
2245	if (auto *Use = dyn_cast<MemoryUseOrDef>(MA))
2246	return Use->getDefiningAccess();
2247	return MA;
2248	}
2249
2250	MemoryAccess *DoNothingMemorySSAWalker::getClobberingMemoryAccess(
2251	MemoryAccess *StartingAccess, const MemoryLocation &) {
2252	if (auto *Use = dyn_cast<MemoryUseOrDef>(StartingAccess))
2253	return Use->getDefiningAccess();
2254	return StartingAccess;
2255	}
2256
2257	void MemoryPhi::deleteMe(DerivedUser *Self) {
2258	delete static_cast<MemoryPhi *>(Self);
2259	}
2260
2261	void MemoryDef::deleteMe(DerivedUser *Self) {
2262	delete static_cast<MemoryDef *>(Self);
2263	}
2264
2265	void MemoryUse::deleteMe(DerivedUser *Self) {
2266	delete static_cast<MemoryUse *>(Self);
2267	}