Bug Summary

File:lib/Transforms/Scalar/NewGVN.cpp
Warning:line 1151, column 9
Called C++ object pointer is null

Annotated Source Code

1//===---- NewGVN.cpp - Global Value Numbering Pass --------------*- C++ -*-===//
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/// \file
10/// This file implements the new LLVM's Global Value Numbering pass.
11/// GVN partitions values computed by a function into congruence classes.
12/// Values ending up in the same congruence class are guaranteed to be the same
13/// for every execution of the program. In that respect, congruency is a
14/// compile-time approximation of equivalence of values at runtime.
15/// The algorithm implemented here uses a sparse formulation and it's based
16/// on the ideas described in the paper:
17/// "A Sparse Algorithm for Predicated Global Value Numbering" from
18/// Karthik Gargi.
19///
20/// A brief overview of the algorithm: The algorithm is essentially the same as
21/// the standard RPO value numbering algorithm (a good reference is the paper
22/// "SCC based value numbering" by L. Taylor Simpson) with one major difference:
23/// The RPO algorithm proceeds, on every iteration, to process every reachable
24/// block and every instruction in that block. This is because the standard RPO
25/// algorithm does not track what things have the same value number, it only
26/// tracks what the value number of a given operation is (the mapping is
27/// operation -> value number). Thus, when a value number of an operation
28/// changes, it must reprocess everything to ensure all uses of a value number
29/// get updated properly. In constrast, the sparse algorithm we use *also*
30/// tracks what operations have a given value number (IE it also tracks the
31/// reverse mapping from value number -> operations with that value number), so
32/// that it only needs to reprocess the instructions that are affected when
33/// something's value number changes. The rest of the algorithm is devoted to
34/// performing symbolic evaluation, forward propagation, and simplification of
35/// operations based on the value numbers deduced so far.
36///
37/// We also do not perform elimination by using any published algorithm. All
38/// published algorithms are O(Instructions). Instead, we use a technique that
39/// is O(number of operations with the same value number), enabling us to skip
40/// trying to eliminate things that have unique value numbers.
41//===----------------------------------------------------------------------===//
42
43#include "llvm/Transforms/Scalar/NewGVN.h"
44#include "llvm/ADT/BitVector.h"
45#include "llvm/ADT/DenseMap.h"
46#include "llvm/ADT/DenseSet.h"
47#include "llvm/ADT/DepthFirstIterator.h"
48#include "llvm/ADT/Hashing.h"
49#include "llvm/ADT/MapVector.h"
50#include "llvm/ADT/PostOrderIterator.h"
51#include "llvm/ADT/STLExtras.h"
52#include "llvm/ADT/SmallPtrSet.h"
53#include "llvm/ADT/SmallSet.h"
54#include "llvm/ADT/SparseBitVector.h"
55#include "llvm/ADT/Statistic.h"
56#include "llvm/ADT/TinyPtrVector.h"
57#include "llvm/Analysis/AliasAnalysis.h"
58#include "llvm/Analysis/AssumptionCache.h"
59#include "llvm/Analysis/CFG.h"
60#include "llvm/Analysis/CFGPrinter.h"
61#include "llvm/Analysis/ConstantFolding.h"
62#include "llvm/Analysis/GlobalsModRef.h"
63#include "llvm/Analysis/InstructionSimplify.h"
64#include "llvm/Analysis/MemoryBuiltins.h"
65#include "llvm/Analysis/MemoryLocation.h"
66#include "llvm/Analysis/MemorySSA.h"
67#include "llvm/Analysis/TargetLibraryInfo.h"
68#include "llvm/IR/DataLayout.h"
69#include "llvm/IR/Dominators.h"
70#include "llvm/IR/GlobalVariable.h"
71#include "llvm/IR/IRBuilder.h"
72#include "llvm/IR/IntrinsicInst.h"
73#include "llvm/IR/LLVMContext.h"
74#include "llvm/IR/Metadata.h"
75#include "llvm/IR/PatternMatch.h"
76#include "llvm/IR/Type.h"
77#include "llvm/Support/Allocator.h"
78#include "llvm/Support/CommandLine.h"
79#include "llvm/Support/Debug.h"
80#include "llvm/Support/DebugCounter.h"
81#include "llvm/Transforms/Scalar.h"
82#include "llvm/Transforms/Scalar/GVNExpression.h"
83#include "llvm/Transforms/Utils/BasicBlockUtils.h"
84#include "llvm/Transforms/Utils/Local.h"
85#include "llvm/Transforms/Utils/PredicateInfo.h"
86#include "llvm/Transforms/Utils/VNCoercion.h"
87#include <numeric>
88#include <unordered_map>
89#include <utility>
90#include <vector>
91using namespace llvm;
92using namespace PatternMatch;
93using namespace llvm::GVNExpression;
94using namespace llvm::VNCoercion;
95#define DEBUG_TYPE"newgvn" "newgvn"
96
97STATISTIC(NumGVNInstrDeleted, "Number of instructions deleted")static llvm::Statistic NumGVNInstrDeleted = {"newgvn", "NumGVNInstrDeleted"
, "Number of instructions deleted", {0}, false}
;
98STATISTIC(NumGVNBlocksDeleted, "Number of blocks deleted")static llvm::Statistic NumGVNBlocksDeleted = {"newgvn", "NumGVNBlocksDeleted"
, "Number of blocks deleted", {0}, false}
;
99STATISTIC(NumGVNOpsSimplified, "Number of Expressions simplified")static llvm::Statistic NumGVNOpsSimplified = {"newgvn", "NumGVNOpsSimplified"
, "Number of Expressions simplified", {0}, false}
;
100STATISTIC(NumGVNPhisAllSame, "Number of PHIs whos arguments are all the same")static llvm::Statistic NumGVNPhisAllSame = {"newgvn", "NumGVNPhisAllSame"
, "Number of PHIs whos arguments are all the same", {0}, false
}
;
101STATISTIC(NumGVNMaxIterations,static llvm::Statistic NumGVNMaxIterations = {"newgvn", "NumGVNMaxIterations"
, "Maximum Number of iterations it took to converge GVN", {0}
, false}
102 "Maximum Number of iterations it took to converge GVN")static llvm::Statistic NumGVNMaxIterations = {"newgvn", "NumGVNMaxIterations"
, "Maximum Number of iterations it took to converge GVN", {0}
, false}
;
103STATISTIC(NumGVNLeaderChanges, "Number of leader changes")static llvm::Statistic NumGVNLeaderChanges = {"newgvn", "NumGVNLeaderChanges"
, "Number of leader changes", {0}, false}
;
104STATISTIC(NumGVNSortedLeaderChanges, "Number of sorted leader changes")static llvm::Statistic NumGVNSortedLeaderChanges = {"newgvn",
"NumGVNSortedLeaderChanges", "Number of sorted leader changes"
, {0}, false}
;
105STATISTIC(NumGVNAvoidedSortedLeaderChanges,static llvm::Statistic NumGVNAvoidedSortedLeaderChanges = {"newgvn"
, "NumGVNAvoidedSortedLeaderChanges", "Number of avoided sorted leader changes"
, {0}, false}
106 "Number of avoided sorted leader changes")static llvm::Statistic NumGVNAvoidedSortedLeaderChanges = {"newgvn"
, "NumGVNAvoidedSortedLeaderChanges", "Number of avoided sorted leader changes"
, {0}, false}
;
107STATISTIC(NumGVNNotMostDominatingLeader,static llvm::Statistic NumGVNNotMostDominatingLeader = {"newgvn"
, "NumGVNNotMostDominatingLeader", "Number of times a member dominated it's new classes' leader"
, {0}, false}
108 "Number of times a member dominated it's new classes' leader")static llvm::Statistic NumGVNNotMostDominatingLeader = {"newgvn"
, "NumGVNNotMostDominatingLeader", "Number of times a member dominated it's new classes' leader"
, {0}, false}
;
109STATISTIC(NumGVNDeadStores, "Number of redundant/dead stores eliminated")static llvm::Statistic NumGVNDeadStores = {"newgvn", "NumGVNDeadStores"
, "Number of redundant/dead stores eliminated", {0}, false}
;
110DEBUG_COUNTER(VNCounter, "newgvn-vn",static const unsigned VNCounter = DebugCounter::registerCounter
("newgvn-vn", "Controls which instructions are value numbered"
);
111 "Controls which instructions are value numbered")static const unsigned VNCounter = DebugCounter::registerCounter
("newgvn-vn", "Controls which instructions are value numbered"
);
112
113// Currently store defining access refinement is too slow due to basicaa being
114// egregiously slow. This flag lets us keep it working while we work on this
115// issue.
116static cl::opt<bool> EnableStoreRefinement("enable-store-refinement",
117 cl::init(false), cl::Hidden);
118
119//===----------------------------------------------------------------------===//
120// GVN Pass
121//===----------------------------------------------------------------------===//
122
123// Anchor methods.
124namespace llvm {
125namespace GVNExpression {
126Expression::~Expression() = default;
127BasicExpression::~BasicExpression() = default;
128CallExpression::~CallExpression() = default;
129LoadExpression::~LoadExpression() = default;
130StoreExpression::~StoreExpression() = default;
131AggregateValueExpression::~AggregateValueExpression() = default;
132PHIExpression::~PHIExpression() = default;
133}
134}
135
136// Tarjan's SCC finding algorithm with Nuutila's improvements
137// SCCIterator is actually fairly complex for the simple thing we want.
138// It also wants to hand us SCC's that are unrelated to the phi node we ask
139// about, and have us process them there or risk redoing work.
140// Graph traits over a filter iterator also doesn't work that well here.
141// This SCC finder is specialized to walk use-def chains, and only follows
142// instructions,
143// not generic values (arguments, etc).
144struct TarjanSCC {
145
146 TarjanSCC() : Components(1) {}
147
148 void Start(const Instruction *Start) {
149 if (Root.lookup(Start) == 0)
150 FindSCC(Start);
151 }
152
153 const SmallPtrSetImpl<const Value *> &getComponentFor(const Value *V) const {
154 unsigned ComponentID = ValueToComponent.lookup(V);
155
156 assert(ComponentID > 0 &&((ComponentID > 0 && "Asking for a component for a value we never processed"
) ? static_cast<void> (0) : __assert_fail ("ComponentID > 0 && \"Asking for a component for a value we never processed\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 157, __PRETTY_FUNCTION__))
157 "Asking for a component for a value we never processed")((ComponentID > 0 && "Asking for a component for a value we never processed"
) ? static_cast<void> (0) : __assert_fail ("ComponentID > 0 && \"Asking for a component for a value we never processed\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 157, __PRETTY_FUNCTION__))
;
158 return Components[ComponentID];
159 }
160
161private:
162 void FindSCC(const Instruction *I) {
163 Root[I] = ++DFSNum;
164 // Store the DFS Number we had before it possibly gets incremented.
165 unsigned int OurDFS = DFSNum;
166 for (auto &Op : I->operands()) {
167 if (auto *InstOp = dyn_cast<Instruction>(Op)) {
168 if (Root.lookup(Op) == 0)
169 FindSCC(InstOp);
170 if (!InComponent.count(Op))
171 Root[I] = std::min(Root.lookup(I), Root.lookup(Op));
172 }
173 }
174 // See if we really were the root of a component, by seeing if we still have
175 // our DFSNumber.
176 // If we do, we are the root of the component, and we have completed a
177 // component. If we do not,
178 // we are not the root of a component, and belong on the component stack.
179 if (Root.lookup(I) == OurDFS) {
180 unsigned ComponentID = Components.size();
181 Components.resize(Components.size() + 1);
182 auto &Component = Components.back();
183 Component.insert(I);
184 DEBUG(dbgs() << "Component root is " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Component root is " << *
I << "\n"; } } while (false)
;
185 InComponent.insert(I);
186 ValueToComponent[I] = ComponentID;
187 // Pop a component off the stack and label it.
188 while (!Stack.empty() && Root.lookup(Stack.back()) >= OurDFS) {
189 auto *Member = Stack.back();
190 DEBUG(dbgs() << "Component member is " << *Member << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Component member is " <<
*Member << "\n"; } } while (false)
;
191 Component.insert(Member);
192 InComponent.insert(Member);
193 ValueToComponent[Member] = ComponentID;
194 Stack.pop_back();
195 }
196 } else {
197 // Part of a component, push to stack
198 Stack.push_back(I);
199 }
200 }
201 unsigned int DFSNum = 1;
202 SmallPtrSet<const Value *, 8> InComponent;
203 DenseMap<const Value *, unsigned int> Root;
204 SmallVector<const Value *, 8> Stack;
205 // Store the components as vector of ptr sets, because we need the topo order
206 // of SCC's, but not individual member order
207 SmallVector<SmallPtrSet<const Value *, 8>, 8> Components;
208 DenseMap<const Value *, unsigned> ValueToComponent;
209};
210// Congruence classes represent the set of expressions/instructions
211// that are all the same *during some scope in the function*.
212// That is, because of the way we perform equality propagation, and
213// because of memory value numbering, it is not correct to assume
214// you can willy-nilly replace any member with any other at any
215// point in the function.
216//
217// For any Value in the Member set, it is valid to replace any dominated member
218// with that Value.
219//
220// Every congruence class has a leader, and the leader is used to symbolize
221// instructions in a canonical way (IE every operand of an instruction that is a
222// member of the same congruence class will always be replaced with leader
223// during symbolization). To simplify symbolization, we keep the leader as a
224// constant if class can be proved to be a constant value. Otherwise, the
225// leader is the member of the value set with the smallest DFS number. Each
226// congruence class also has a defining expression, though the expression may be
227// null. If it exists, it can be used for forward propagation and reassociation
228// of values.
229
230// For memory, we also track a representative MemoryAccess, and a set of memory
231// members for MemoryPhis (which have no real instructions). Note that for
232// memory, it seems tempting to try to split the memory members into a
233// MemoryCongruenceClass or something. Unfortunately, this does not work
234// easily. The value numbering of a given memory expression depends on the
235// leader of the memory congruence class, and the leader of memory congruence
236// class depends on the value numbering of a given memory expression. This
237// leads to wasted propagation, and in some cases, missed optimization. For
238// example: If we had value numbered two stores together before, but now do not,
239// we move them to a new value congruence class. This in turn will move at one
240// of the memorydefs to a new memory congruence class. Which in turn, affects
241// the value numbering of the stores we just value numbered (because the memory
242// congruence class is part of the value number). So while theoretically
243// possible to split them up, it turns out to be *incredibly* complicated to get
244// it to work right, because of the interdependency. While structurally
245// slightly messier, it is algorithmically much simpler and faster to do what we
246// do here, and track them both at once in the same class.
247// Note: The default iterators for this class iterate over values
248class CongruenceClass {
249public:
250 using MemberType = Value;
251 using MemberSet = SmallPtrSet<MemberType *, 4>;
252 using MemoryMemberType = MemoryPhi;
253 using MemoryMemberSet = SmallPtrSet<const MemoryMemberType *, 2>;
254
255 explicit CongruenceClass(unsigned ID) : ID(ID) {}
256 CongruenceClass(unsigned ID, Value *Leader, const Expression *E)
257 : ID(ID), RepLeader(Leader), DefiningExpr(E) {}
258 unsigned getID() const { return ID; }
259 // True if this class has no members left. This is mainly used for assertion
260 // purposes, and for skipping empty classes.
261 bool isDead() const {
262 // If it's both dead from a value perspective, and dead from a memory
263 // perspective, it's really dead.
264 return empty() && memory_empty();
265 }
266 // Leader functions
267 Value *getLeader() const { return RepLeader; }
268 void setLeader(Value *Leader) { RepLeader = Leader; }
269 const std::pair<Value *, unsigned int> &getNextLeader() const {
270 return NextLeader;
271 }
272 void resetNextLeader() { NextLeader = {nullptr, ~0}; }
273
274 void addPossibleNextLeader(std::pair<Value *, unsigned int> LeaderPair) {
275 if (LeaderPair.second < NextLeader.second)
276 NextLeader = LeaderPair;
277 }
278
279 Value *getStoredValue() const { return RepStoredValue; }
280 void setStoredValue(Value *Leader) { RepStoredValue = Leader; }
281 const MemoryAccess *getMemoryLeader() const { return RepMemoryAccess; }
282 void setMemoryLeader(const MemoryAccess *Leader) { RepMemoryAccess = Leader; }
283
284 // Forward propagation info
285 const Expression *getDefiningExpr() const { return DefiningExpr; }
286 void setDefiningExpr(const Expression *E) { DefiningExpr = E; }
287
288 // Value member set
289 bool empty() const { return Members.empty(); }
290 unsigned size() const { return Members.size(); }
291 MemberSet::const_iterator begin() const { return Members.begin(); }
292 MemberSet::const_iterator end() const { return Members.end(); }
293 void insert(MemberType *M) { Members.insert(M); }
294 void erase(MemberType *M) { Members.erase(M); }
295 void swap(MemberSet &Other) { Members.swap(Other); }
296
297 // Memory member set
298 bool memory_empty() const { return MemoryMembers.empty(); }
299 unsigned memory_size() const { return MemoryMembers.size(); }
300 MemoryMemberSet::const_iterator memory_begin() const {
301 return MemoryMembers.begin();
302 }
303 MemoryMemberSet::const_iterator memory_end() const {
304 return MemoryMembers.end();
305 }
306 iterator_range<MemoryMemberSet::const_iterator> memory() const {
307 return make_range(memory_begin(), memory_end());
308 }
309 void memory_insert(const MemoryMemberType *M) { MemoryMembers.insert(M); }
310 void memory_erase(const MemoryMemberType *M) { MemoryMembers.erase(M); }
311
312 // Store count
313 unsigned getStoreCount() const { return StoreCount; }
314 void incStoreCount() { ++StoreCount; }
315 void decStoreCount() {
316 assert(StoreCount != 0 && "Store count went negative")((StoreCount != 0 && "Store count went negative") ? static_cast
<void> (0) : __assert_fail ("StoreCount != 0 && \"Store count went negative\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 316, __PRETTY_FUNCTION__))
;
317 --StoreCount;
318 }
319
320 // Return true if two congruence classes are equivalent to each other. This
321 // means
322 // that every field but the ID number and the dead field are equivalent.
323 bool isEquivalentTo(const CongruenceClass *Other) const {
324 if (!Other)
325 return false;
326 if (this == Other)
327 return true;
328
329 if (std::tie(StoreCount, RepLeader, RepStoredValue, RepMemoryAccess) !=
330 std::tie(Other->StoreCount, Other->RepLeader, Other->RepStoredValue,
331 Other->RepMemoryAccess))
332 return false;
333 if (DefiningExpr != Other->DefiningExpr)
334 if (!DefiningExpr || !Other->DefiningExpr ||
335 *DefiningExpr != *Other->DefiningExpr)
336 return false;
337 // We need some ordered set
338 std::set<Value *> AMembers(Members.begin(), Members.end());
339 std::set<Value *> BMembers(Members.begin(), Members.end());
340 return AMembers == BMembers;
341 }
342
343private:
344 unsigned ID;
345 // Representative leader.
346 Value *RepLeader = nullptr;
347 // The most dominating leader after our current leader, because the member set
348 // is not sorted and is expensive to keep sorted all the time.
349 std::pair<Value *, unsigned int> NextLeader = {nullptr, ~0U};
350 // If this is represented by a store, the value of the store.
351 Value *RepStoredValue = nullptr;
352 // If this class contains MemoryDefs or MemoryPhis, this is the leading memory
353 // access.
354 const MemoryAccess *RepMemoryAccess = nullptr;
355 // Defining Expression.
356 const Expression *DefiningExpr = nullptr;
357 // Actual members of this class.
358 MemberSet Members;
359 // This is the set of MemoryPhis that exist in the class. MemoryDefs and
360 // MemoryUses have real instructions representing them, so we only need to
361 // track MemoryPhis here.
362 MemoryMemberSet MemoryMembers;
363 // Number of stores in this congruence class.
364 // This is used so we can detect store equivalence changes properly.
365 int StoreCount = 0;
366};
367
368namespace llvm {
369template <> struct DenseMapInfo<const Expression *> {
370 static const Expression *getEmptyKey() {
371 auto Val = static_cast<uintptr_t>(-1);
372 Val <<= PointerLikeTypeTraits<const Expression *>::NumLowBitsAvailable;
373 return reinterpret_cast<const Expression *>(Val);
374 }
375 static const Expression *getTombstoneKey() {
376 auto Val = static_cast<uintptr_t>(~1U);
377 Val <<= PointerLikeTypeTraits<const Expression *>::NumLowBitsAvailable;
378 return reinterpret_cast<const Expression *>(Val);
379 }
380 static unsigned getHashValue(const Expression *V) {
381 return static_cast<unsigned>(V->getHashValue());
382 }
383 static bool isEqual(const Expression *LHS, const Expression *RHS) {
384 if (LHS == RHS)
385 return true;
386 if (LHS == getTombstoneKey() || RHS == getTombstoneKey() ||
387 LHS == getEmptyKey() || RHS == getEmptyKey())
388 return false;
389 return *LHS == *RHS;
390 }
391};
392} // end namespace llvm
393
394namespace {
395class NewGVN {
396 Function &F;
397 DominatorTree *DT;
398 const TargetLibraryInfo *TLI;
399 AliasAnalysis *AA;
400 MemorySSA *MSSA;
401 MemorySSAWalker *MSSAWalker;
402 const DataLayout &DL;
403 std::unique_ptr<PredicateInfo> PredInfo;
404 BumpPtrAllocator ExpressionAllocator;
405 ArrayRecycler<Value *> ArgRecycler;
406 TarjanSCC SCCFinder;
407 const SimplifyQuery SQ;
408
409 // Number of function arguments, used by ranking
410 unsigned int NumFuncArgs;
411
412 // RPOOrdering of basic blocks
413 DenseMap<const DomTreeNode *, unsigned> RPOOrdering;
414
415 // Congruence class info.
416
417 // This class is called INITIAL in the paper. It is the class everything
418 // startsout in, and represents any value. Being an optimistic analysis,
419 // anything in the TOP class has the value TOP, which is indeterminate and
420 // equivalent to everything.
421 CongruenceClass *TOPClass;
422 std::vector<CongruenceClass *> CongruenceClasses;
423 unsigned NextCongruenceNum;
424
425 // Value Mappings.
426 DenseMap<Value *, CongruenceClass *> ValueToClass;
427 DenseMap<Value *, const Expression *> ValueToExpression;
428
429 // Mapping from predicate info we used to the instructions we used it with.
430 // In order to correctly ensure propagation, we must keep track of what
431 // comparisons we used, so that when the values of the comparisons change, we
432 // propagate the information to the places we used the comparison.
433 DenseMap<const Value *, SmallPtrSet<Instruction *, 2>> PredicateToUsers;
434 // Mapping from MemoryAccess we used to the MemoryAccess we used it with. Has
435 // the same reasoning as PredicateToUsers. When we skip MemoryAccesses for
436 // stores, we no longer can rely solely on the def-use chains of MemorySSA.
437 DenseMap<const MemoryAccess *, SmallPtrSet<MemoryAccess *, 2>> MemoryToUsers;
438
439 // A table storing which memorydefs/phis represent a memory state provably
440 // equivalent to another memory state.
441 // We could use the congruence class machinery, but the MemoryAccess's are
442 // abstract memory states, so they can only ever be equivalent to each other,
443 // and not to constants, etc.
444 DenseMap<const MemoryAccess *, CongruenceClass *> MemoryAccessToClass;
445
446 // We could, if we wanted, build MemoryPhiExpressions and
447 // MemoryVariableExpressions, etc, and value number them the same way we value
448 // number phi expressions. For the moment, this seems like overkill. They
449 // can only exist in one of three states: they can be TOP (equal to
450 // everything), Equivalent to something else, or unique. Because we do not
451 // create expressions for them, we need to simulate leader change not just
452 // when they change class, but when they change state. Note: We can do the
453 // same thing for phis, and avoid having phi expressions if we wanted, We
454 // should eventually unify in one direction or the other, so this is a little
455 // bit of an experiment in which turns out easier to maintain.
456 enum MemoryPhiState { MPS_Invalid, MPS_TOP, MPS_Equivalent, MPS_Unique };
457 DenseMap<const MemoryPhi *, MemoryPhiState> MemoryPhiState;
458
459 enum PhiCycleState { PCS_Unknown, PCS_CycleFree, PCS_Cycle };
460 DenseMap<const PHINode *, PhiCycleState> PhiCycleState;
461 // Expression to class mapping.
462 using ExpressionClassMap = DenseMap<const Expression *, CongruenceClass *>;
463 ExpressionClassMap ExpressionToClass;
464
465 // Which values have changed as a result of leader changes.
466 SmallPtrSet<Value *, 8> LeaderChanges;
467
468 // Reachability info.
469 using BlockEdge = BasicBlockEdge;
470 DenseSet<BlockEdge> ReachableEdges;
471 SmallPtrSet<const BasicBlock *, 8> ReachableBlocks;
472
473 // This is a bitvector because, on larger functions, we may have
474 // thousands of touched instructions at once (entire blocks,
475 // instructions with hundreds of uses, etc). Even with optimization
476 // for when we mark whole blocks as touched, when this was a
477 // SmallPtrSet or DenseSet, for some functions, we spent >20% of all
478 // the time in GVN just managing this list. The bitvector, on the
479 // other hand, efficiently supports test/set/clear of both
480 // individual and ranges, as well as "find next element" This
481 // enables us to use it as a worklist with essentially 0 cost.
482 BitVector TouchedInstructions;
483
484 DenseMap<const BasicBlock *, std::pair<unsigned, unsigned>> BlockInstRange;
485
486#ifndef NDEBUG
487 // Debugging for how many times each block and instruction got processed.
488 DenseMap<const Value *, unsigned> ProcessedCount;
489#endif
490
491 // DFS info.
492 // This contains a mapping from Instructions to DFS numbers.
493 // The numbering starts at 1. An instruction with DFS number zero
494 // means that the instruction is dead.
495 DenseMap<const Value *, unsigned> InstrDFS;
496
497 // This contains the mapping DFS numbers to instructions.
498 SmallVector<Value *, 32> DFSToInstr;
499
500 // Deletion info.
501 SmallPtrSet<Instruction *, 8> InstructionsToErase;
502
503public:
504 NewGVN(Function &F, DominatorTree *DT, AssumptionCache *AC,
505 TargetLibraryInfo *TLI, AliasAnalysis *AA, MemorySSA *MSSA,
506 const DataLayout &DL)
507 : F(F), DT(DT), TLI(TLI), AA(AA), MSSA(MSSA), DL(DL),
508 PredInfo(make_unique<PredicateInfo>(F, *DT, *AC)), SQ(DL, TLI, DT, AC) {
509 }
510 bool runGVN();
511
512private:
513 // Expression handling.
514 const Expression *createExpression(Instruction *);
515 const Expression *createBinaryExpression(unsigned, Type *, Value *, Value *);
516 PHIExpression *createPHIExpression(Instruction *, bool &HasBackedge,
517 bool &AllConstant);
518 const VariableExpression *createVariableExpression(Value *);
519 const ConstantExpression *createConstantExpression(Constant *);
520 const Expression *createVariableOrConstant(Value *V);
521 const UnknownExpression *createUnknownExpression(Instruction *);
522 const StoreExpression *createStoreExpression(StoreInst *,
523 const MemoryAccess *);
524 LoadExpression *createLoadExpression(Type *, Value *, LoadInst *,
525 const MemoryAccess *);
526 const CallExpression *createCallExpression(CallInst *, const MemoryAccess *);
527 const AggregateValueExpression *createAggregateValueExpression(Instruction *);
528 bool setBasicExpressionInfo(Instruction *, BasicExpression *);
529
530 // Congruence class handling.
531 CongruenceClass *createCongruenceClass(Value *Leader, const Expression *E) {
532 auto *result = new CongruenceClass(NextCongruenceNum++, Leader, E);
533 CongruenceClasses.emplace_back(result);
534 return result;
535 }
536
537 CongruenceClass *createMemoryClass(MemoryAccess *MA) {
538 auto *CC = createCongruenceClass(nullptr, nullptr);
539 CC->setMemoryLeader(MA);
540 return CC;
541 }
542 CongruenceClass *ensureLeaderOfMemoryClass(MemoryAccess *MA) {
543 auto *CC = getMemoryClass(MA);
544 if (CC->getMemoryLeader() != MA)
545 CC = createMemoryClass(MA);
546 return CC;
547 }
548
549 CongruenceClass *createSingletonCongruenceClass(Value *Member) {
550 CongruenceClass *CClass = createCongruenceClass(Member, nullptr);
551 CClass->insert(Member);
552 ValueToClass[Member] = CClass;
553 return CClass;
554 }
555 void initializeCongruenceClasses(Function &F);
556
557 // Value number an Instruction or MemoryPhi.
558 void valueNumberMemoryPhi(MemoryPhi *);
559 void valueNumberInstruction(Instruction *);
560
561 // Symbolic evaluation.
562 const Expression *checkSimplificationResults(Expression *, Instruction *,
563 Value *);
564 const Expression *performSymbolicEvaluation(Value *);
565 const Expression *performSymbolicLoadCoercion(Type *, Value *, LoadInst *,
566 Instruction *, MemoryAccess *);
567 const Expression *performSymbolicLoadEvaluation(Instruction *);
568 const Expression *performSymbolicStoreEvaluation(Instruction *);
569 const Expression *performSymbolicCallEvaluation(Instruction *);
570 const Expression *performSymbolicPHIEvaluation(Instruction *);
571 const Expression *performSymbolicAggrValueEvaluation(Instruction *);
572 const Expression *performSymbolicCmpEvaluation(Instruction *);
573 const Expression *performSymbolicPredicateInfoEvaluation(Instruction *);
574
575 // Congruence finding.
576 bool someEquivalentDominates(const Instruction *, const Instruction *) const;
577 Value *lookupOperandLeader(Value *) const;
578 void performCongruenceFinding(Instruction *, const Expression *);
579 void moveValueToNewCongruenceClass(Instruction *, const Expression *,
580 CongruenceClass *, CongruenceClass *);
581 void moveMemoryToNewCongruenceClass(Instruction *, MemoryAccess *,
582 CongruenceClass *, CongruenceClass *);
583 Value *getNextValueLeader(CongruenceClass *) const;
584 const MemoryAccess *getNextMemoryLeader(CongruenceClass *) const;
585 bool setMemoryClass(const MemoryAccess *From, CongruenceClass *To);
586 CongruenceClass *getMemoryClass(const MemoryAccess *MA) const;
587 const MemoryAccess *lookupMemoryLeader(const MemoryAccess *) const;
588 bool isMemoryAccessTop(const MemoryAccess *) const;
589
590 // Ranking
591 unsigned int getRank(const Value *) const;
592 bool shouldSwapOperands(const Value *, const Value *) const;
593
594 // Reachability handling.
595 void updateReachableEdge(BasicBlock *, BasicBlock *);
596 void processOutgoingEdges(TerminatorInst *, BasicBlock *);
597 Value *findConditionEquivalence(Value *) const;
598
599 // Elimination.
600 struct ValueDFS;
601 void convertClassToDFSOrdered(const CongruenceClass &,
602 SmallVectorImpl<ValueDFS> &,
603 DenseMap<const Value *, unsigned int> &,
604 SmallPtrSetImpl<Instruction *> &) const;
605 void convertClassToLoadsAndStores(const CongruenceClass &,
606 SmallVectorImpl<ValueDFS> &) const;
607
608 bool eliminateInstructions(Function &);
609 void replaceInstruction(Instruction *, Value *);
610 void markInstructionForDeletion(Instruction *);
611 void deleteInstructionsInBlock(BasicBlock *);
612
613 // New instruction creation.
614 void handleNewInstruction(Instruction *){};
615
616 // Various instruction touch utilities
617 void markUsersTouched(Value *);
618 void markMemoryUsersTouched(const MemoryAccess *);
619 void markMemoryDefTouched(const MemoryAccess *);
620 void markPredicateUsersTouched(Instruction *);
621 void markValueLeaderChangeTouched(CongruenceClass *CC);
622 void markMemoryLeaderChangeTouched(CongruenceClass *CC);
623 void addPredicateUsers(const PredicateBase *, Instruction *);
624 void addMemoryUsers(const MemoryAccess *To, MemoryAccess *U);
625
626 // Main loop of value numbering
627 void iterateTouchedInstructions();
628
629 // Utilities.
630 void cleanupTables();
631 std::pair<unsigned, unsigned> assignDFSNumbers(BasicBlock *, unsigned);
632 void updateProcessedCount(Value *V);
633 void verifyMemoryCongruency() const;
634 void verifyIterationSettled(Function &F);
635 bool singleReachablePHIPath(const MemoryAccess *, const MemoryAccess *) const;
636 BasicBlock *getBlockForValue(Value *V) const;
637 void deleteExpression(const Expression *E);
638 unsigned InstrToDFSNum(const Value *V) const {
639 assert(isa<Instruction>(V) && "This should not be used for MemoryAccesses")((isa<Instruction>(V) && "This should not be used for MemoryAccesses"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(V) && \"This should not be used for MemoryAccesses\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 639, __PRETTY_FUNCTION__))
;
640 return InstrDFS.lookup(V);
641 }
642
643 unsigned InstrToDFSNum(const MemoryAccess *MA) const {
644 return MemoryToDFSNum(MA);
645 }
646 Value *InstrFromDFSNum(unsigned DFSNum) { return DFSToInstr[DFSNum]; }
647 // Given a MemoryAccess, return the relevant instruction DFS number. Note:
648 // This deliberately takes a value so it can be used with Use's, which will
649 // auto-convert to Value's but not to MemoryAccess's.
650 unsigned MemoryToDFSNum(const Value *MA) const {
651 assert(isa<MemoryAccess>(MA) &&((isa<MemoryAccess>(MA) && "This should not be used with instructions"
) ? static_cast<void> (0) : __assert_fail ("isa<MemoryAccess>(MA) && \"This should not be used with instructions\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 652, __PRETTY_FUNCTION__))
652 "This should not be used with instructions")((isa<MemoryAccess>(MA) && "This should not be used with instructions"
) ? static_cast<void> (0) : __assert_fail ("isa<MemoryAccess>(MA) && \"This should not be used with instructions\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 652, __PRETTY_FUNCTION__))
;
653 return isa<MemoryUseOrDef>(MA)
654 ? InstrToDFSNum(cast<MemoryUseOrDef>(MA)->getMemoryInst())
655 : InstrDFS.lookup(MA);
656 }
657 bool isCycleFree(const PHINode *PN);
658 template <class T, class Range> T *getMinDFSOfRange(const Range &) const;
659 // Debug counter info. When verifying, we have to reset the value numbering
660 // debug counter to the same state it started in to get the same results.
661 std::pair<int, int> StartingVNCounter;
662};
663} // end anonymous namespace
664
665template <typename T>
666static bool equalsLoadStoreHelper(const T &LHS, const Expression &RHS) {
667 if (!isa<LoadExpression>(RHS) && !isa<StoreExpression>(RHS))
668 return false;
669 return LHS.MemoryExpression::equals(RHS);
670}
671
672bool LoadExpression::equals(const Expression &Other) const {
673 return equalsLoadStoreHelper(*this, Other);
674}
675
676bool StoreExpression::equals(const Expression &Other) const {
677 if (!equalsLoadStoreHelper(*this, Other))
678 return false;
679 // Make sure that store vs store includes the value operand.
680 if (const auto *S = dyn_cast<StoreExpression>(&Other))
681 if (getStoredValue() != S->getStoredValue())
682 return false;
683 return true;
684}
685
686#ifndef NDEBUG
687static std::string getBlockName(const BasicBlock *B) {
688 return DOTGraphTraits<const Function *>::getSimpleNodeLabel(B, nullptr);
689}
690#endif
691
692// Get the basic block from an instruction/memory value.
693BasicBlock *NewGVN::getBlockForValue(Value *V) const {
694 if (auto *I = dyn_cast<Instruction>(V))
695 return I->getParent();
696 else if (auto *MP = dyn_cast<MemoryPhi>(V))
697 return MP->getBlock();
698 llvm_unreachable("Should have been able to figure out a block for our value")::llvm::llvm_unreachable_internal("Should have been able to figure out a block for our value"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 698)
;
699 return nullptr;
700}
701
702// Delete a definitely dead expression, so it can be reused by the expression
703// allocator. Some of these are not in creation functions, so we have to accept
704// const versions.
705void NewGVN::deleteExpression(const Expression *E) {
706 assert(isa<BasicExpression>(E))((isa<BasicExpression>(E)) ? static_cast<void> (0
) : __assert_fail ("isa<BasicExpression>(E)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 706, __PRETTY_FUNCTION__))
;
707 auto *BE = cast<BasicExpression>(E);
708 const_cast<BasicExpression *>(BE)->deallocateOperands(ArgRecycler);
709 ExpressionAllocator.Deallocate(E);
710}
711
712PHIExpression *NewGVN::createPHIExpression(Instruction *I, bool &HasBackedge,
713 bool &AllConstant) {
714 BasicBlock *PHIBlock = I->getParent();
715 auto *PN = cast<PHINode>(I);
716 auto *E =
717 new (ExpressionAllocator) PHIExpression(PN->getNumOperands(), PHIBlock);
718
719 E->allocateOperands(ArgRecycler, ExpressionAllocator);
720 E->setType(I->getType());
721 E->setOpcode(I->getOpcode());
722
723 unsigned PHIRPO = RPOOrdering.lookup(DT->getNode(PHIBlock));
724
725 // Filter out unreachable phi operands.
726 auto Filtered = make_filter_range(PN->operands(), [&](const Use &U) {
727 return ReachableEdges.count({PN->getIncomingBlock(U), PHIBlock});
728 });
729
730 std::transform(Filtered.begin(), Filtered.end(), op_inserter(E),
731 [&](const Use &U) -> Value * {
732 auto *BB = PN->getIncomingBlock(U);
733 auto *DTN = DT->getNode(BB);
734 if (RPOOrdering.lookup(DTN) >= PHIRPO)
735 HasBackedge = true;
736 AllConstant &= isa<UndefValue>(U) || isa<Constant>(U);
737
738 // Don't try to transform self-defined phis.
739 if (U == PN)
740 return PN;
741 return lookupOperandLeader(U);
742 });
743 return E;
744}
745
746// Set basic expression info (Arguments, type, opcode) for Expression
747// E from Instruction I in block B.
748bool NewGVN::setBasicExpressionInfo(Instruction *I, BasicExpression *E) {
749 bool AllConstant = true;
750 if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
751 E->setType(GEP->getSourceElementType());
752 else
753 E->setType(I->getType());
754 E->setOpcode(I->getOpcode());
755 E->allocateOperands(ArgRecycler, ExpressionAllocator);
756
757 // Transform the operand array into an operand leader array, and keep track of
758 // whether all members are constant.
759 std::transform(I->op_begin(), I->op_end(), op_inserter(E), [&](Value *O) {
760 auto Operand = lookupOperandLeader(O);
761 AllConstant &= isa<Constant>(Operand);
762 return Operand;
763 });
764
765 return AllConstant;
766}
767
768const Expression *NewGVN::createBinaryExpression(unsigned Opcode, Type *T,
769 Value *Arg1, Value *Arg2) {
770 auto *E = new (ExpressionAllocator) BasicExpression(2);
771
772 E->setType(T);
773 E->setOpcode(Opcode);
774 E->allocateOperands(ArgRecycler, ExpressionAllocator);
775 if (Instruction::isCommutative(Opcode)) {
776 // Ensure that commutative instructions that only differ by a permutation
777 // of their operands get the same value number by sorting the operand value
778 // numbers. Since all commutative instructions have two operands it is more
779 // efficient to sort by hand rather than using, say, std::sort.
780 if (shouldSwapOperands(Arg1, Arg2))
781 std::swap(Arg1, Arg2);
782 }
783 E->op_push_back(lookupOperandLeader(Arg1));
784 E->op_push_back(lookupOperandLeader(Arg2));
785
786 Value *V = SimplifyBinOp(Opcode, E->getOperand(0), E->getOperand(1), SQ);
787 if (const Expression *SimplifiedE = checkSimplificationResults(E, nullptr, V))
788 return SimplifiedE;
789 return E;
790}
791
792// Take a Value returned by simplification of Expression E/Instruction
793// I, and see if it resulted in a simpler expression. If so, return
794// that expression.
795// TODO: Once finished, this should not take an Instruction, we only
796// use it for printing.
797const Expression *NewGVN::checkSimplificationResults(Expression *E,
798 Instruction *I, Value *V) {
799 if (!V)
800 return nullptr;
801 if (auto *C = dyn_cast<Constant>(V)) {
802 if (I)
803 DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " constant " << *C << "\n"; } } while
(false)
804 << " constant " << *C << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " constant " << *C << "\n"; } } while
(false)
;
805 NumGVNOpsSimplified++;
806 assert(isa<BasicExpression>(E) &&((isa<BasicExpression>(E) && "We should always have had a basic expression here"
) ? static_cast<void> (0) : __assert_fail ("isa<BasicExpression>(E) && \"We should always have had a basic expression here\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 807, __PRETTY_FUNCTION__))
807 "We should always have had a basic expression here")((isa<BasicExpression>(E) && "We should always have had a basic expression here"
) ? static_cast<void> (0) : __assert_fail ("isa<BasicExpression>(E) && \"We should always have had a basic expression here\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 807, __PRETTY_FUNCTION__))
;
808 deleteExpression(E);
809 return createConstantExpression(C);
810 } else if (isa<Argument>(V) || isa<GlobalVariable>(V)) {
811 if (I)
812 DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " variable " << *V << "\n"; } } while
(false)
813 << " variable " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " variable " << *V << "\n"; } } while
(false)
;
814 deleteExpression(E);
815 return createVariableExpression(V);
816 }
817
818 CongruenceClass *CC = ValueToClass.lookup(V);
819 if (CC && CC->getDefiningExpr()) {
820 if (I)
821 DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " expression " << *V << "\n"; } }
while (false)
822 << " expression " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " expression " << *V << "\n"; } }
while (false)
;
823 NumGVNOpsSimplified++;
824 deleteExpression(E);
825 return CC->getDefiningExpr();
826 }
827 return nullptr;
828}
829
830const Expression *NewGVN::createExpression(Instruction *I) {
831 auto *E = new (ExpressionAllocator) BasicExpression(I->getNumOperands());
832
833 bool AllConstant = setBasicExpressionInfo(I, E);
834
835 if (I->isCommutative()) {
836 // Ensure that commutative instructions that only differ by a permutation
837 // of their operands get the same value number by sorting the operand value
838 // numbers. Since all commutative instructions have two operands it is more
839 // efficient to sort by hand rather than using, say, std::sort.
840 assert(I->getNumOperands() == 2 && "Unsupported commutative instruction!")((I->getNumOperands() == 2 && "Unsupported commutative instruction!"
) ? static_cast<void> (0) : __assert_fail ("I->getNumOperands() == 2 && \"Unsupported commutative instruction!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 840, __PRETTY_FUNCTION__))
;
841 if (shouldSwapOperands(E->getOperand(0), E->getOperand(1)))
842 E->swapOperands(0, 1);
843 }
844
845 // Perform simplificaiton
846 // TODO: Right now we only check to see if we get a constant result.
847 // We may get a less than constant, but still better, result for
848 // some operations.
849 // IE
850 // add 0, x -> x
851 // and x, x -> x
852 // We should handle this by simply rewriting the expression.
853 if (auto *CI = dyn_cast<CmpInst>(I)) {
854 // Sort the operand value numbers so x<y and y>x get the same value
855 // number.
856 CmpInst::Predicate Predicate = CI->getPredicate();
857 if (shouldSwapOperands(E->getOperand(0), E->getOperand(1))) {
858 E->swapOperands(0, 1);
859 Predicate = CmpInst::getSwappedPredicate(Predicate);
860 }
861 E->setOpcode((CI->getOpcode() << 8) | Predicate);
862 // TODO: 25% of our time is spent in SimplifyCmpInst with pointer operands
863 assert(I->getOperand(0)->getType() == I->getOperand(1)->getType() &&((I->getOperand(0)->getType() == I->getOperand(1)->
getType() && "Wrong types on cmp instruction") ? static_cast
<void> (0) : __assert_fail ("I->getOperand(0)->getType() == I->getOperand(1)->getType() && \"Wrong types on cmp instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 864, __PRETTY_FUNCTION__))
864 "Wrong types on cmp instruction")((I->getOperand(0)->getType() == I->getOperand(1)->
getType() && "Wrong types on cmp instruction") ? static_cast
<void> (0) : __assert_fail ("I->getOperand(0)->getType() == I->getOperand(1)->getType() && \"Wrong types on cmp instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 864, __PRETTY_FUNCTION__))
;
865 assert((E->getOperand(0)->getType() == I->getOperand(0)->getType() &&(((E->getOperand(0)->getType() == I->getOperand(0)->
getType() && E->getOperand(1)->getType() == I->
getOperand(1)->getType())) ? static_cast<void> (0) :
__assert_fail ("(E->getOperand(0)->getType() == I->getOperand(0)->getType() && E->getOperand(1)->getType() == I->getOperand(1)->getType())"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 866, __PRETTY_FUNCTION__))
866 E->getOperand(1)->getType() == I->getOperand(1)->getType()))(((E->getOperand(0)->getType() == I->getOperand(0)->
getType() && E->getOperand(1)->getType() == I->
getOperand(1)->getType())) ? static_cast<void> (0) :
__assert_fail ("(E->getOperand(0)->getType() == I->getOperand(0)->getType() && E->getOperand(1)->getType() == I->getOperand(1)->getType())"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 866, __PRETTY_FUNCTION__))
;
867 Value *V =
868 SimplifyCmpInst(Predicate, E->getOperand(0), E->getOperand(1), SQ);
869 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
870 return SimplifiedE;
871 } else if (isa<SelectInst>(I)) {
872 if (isa<Constant>(E->getOperand(0)) ||
873 E->getOperand(0) == E->getOperand(1)) {
874 assert(E->getOperand(1)->getType() == I->getOperand(1)->getType() &&((E->getOperand(1)->getType() == I->getOperand(1)->
getType() && E->getOperand(2)->getType() == I->
getOperand(2)->getType()) ? static_cast<void> (0) : __assert_fail
("E->getOperand(1)->getType() == I->getOperand(1)->getType() && E->getOperand(2)->getType() == I->getOperand(2)->getType()"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 875, __PRETTY_FUNCTION__))
875 E->getOperand(2)->getType() == I->getOperand(2)->getType())((E->getOperand(1)->getType() == I->getOperand(1)->
getType() && E->getOperand(2)->getType() == I->
getOperand(2)->getType()) ? static_cast<void> (0) : __assert_fail
("E->getOperand(1)->getType() == I->getOperand(1)->getType() && E->getOperand(2)->getType() == I->getOperand(2)->getType()"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 875, __PRETTY_FUNCTION__))
;
876 Value *V = SimplifySelectInst(E->getOperand(0), E->getOperand(1),
877 E->getOperand(2), SQ);
878 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
879 return SimplifiedE;
880 }
881 } else if (I->isBinaryOp()) {
882 Value *V =
883 SimplifyBinOp(E->getOpcode(), E->getOperand(0), E->getOperand(1), SQ);
884 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
885 return SimplifiedE;
886 } else if (auto *BI = dyn_cast<BitCastInst>(I)) {
887 Value *V =
888 SimplifyCastInst(BI->getOpcode(), BI->getOperand(0), BI->getType(), SQ);
889 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
890 return SimplifiedE;
891 } else if (isa<GetElementPtrInst>(I)) {
892 Value *V = SimplifyGEPInst(
893 E->getType(), ArrayRef<Value *>(E->op_begin(), E->op_end()), SQ);
894 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
895 return SimplifiedE;
896 } else if (AllConstant) {
897 // We don't bother trying to simplify unless all of the operands
898 // were constant.
899 // TODO: There are a lot of Simplify*'s we could call here, if we
900 // wanted to. The original motivating case for this code was a
901 // zext i1 false to i8, which we don't have an interface to
902 // simplify (IE there is no SimplifyZExt).
903
904 SmallVector<Constant *, 8> C;
905 for (Value *Arg : E->operands())
906 C.emplace_back(cast<Constant>(Arg));
907
908 if (Value *V = ConstantFoldInstOperands(I, C, DL, TLI))
909 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
910 return SimplifiedE;
911 }
912 return E;
913}
914
915const AggregateValueExpression *
916NewGVN::createAggregateValueExpression(Instruction *I) {
917 if (auto *II = dyn_cast<InsertValueInst>(I)) {
918 auto *E = new (ExpressionAllocator)
919 AggregateValueExpression(I->getNumOperands(), II->getNumIndices());
920 setBasicExpressionInfo(I, E);
921 E->allocateIntOperands(ExpressionAllocator);
922 std::copy(II->idx_begin(), II->idx_end(), int_op_inserter(E));
923 return E;
924 } else if (auto *EI = dyn_cast<ExtractValueInst>(I)) {
925 auto *E = new (ExpressionAllocator)
926 AggregateValueExpression(I->getNumOperands(), EI->getNumIndices());
927 setBasicExpressionInfo(EI, E);
928 E->allocateIntOperands(ExpressionAllocator);
929 std::copy(EI->idx_begin(), EI->idx_end(), int_op_inserter(E));
930 return E;
931 }
932 llvm_unreachable("Unhandled type of aggregate value operation")::llvm::llvm_unreachable_internal("Unhandled type of aggregate value operation"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 932)
;
933}
934
935const VariableExpression *NewGVN::createVariableExpression(Value *V) {
936 auto *E = new (ExpressionAllocator) VariableExpression(V);
937 E->setOpcode(V->getValueID());
938 return E;
939}
940
941const Expression *NewGVN::createVariableOrConstant(Value *V) {
942 if (auto *C = dyn_cast<Constant>(V))
943 return createConstantExpression(C);
944 return createVariableExpression(V);
945}
946
947const ConstantExpression *NewGVN::createConstantExpression(Constant *C) {
948 auto *E = new (ExpressionAllocator) ConstantExpression(C);
949 E->setOpcode(C->getValueID());
950 return E;
951}
952
953const UnknownExpression *NewGVN::createUnknownExpression(Instruction *I) {
954 auto *E = new (ExpressionAllocator) UnknownExpression(I);
955 E->setOpcode(I->getOpcode());
956 return E;
957}
958
959const CallExpression *NewGVN::createCallExpression(CallInst *CI,
960 const MemoryAccess *MA) {
961 // FIXME: Add operand bundles for calls.
962 auto *E =
963 new (ExpressionAllocator) CallExpression(CI->getNumOperands(), CI, MA);
964 setBasicExpressionInfo(CI, E);
965 return E;
966}
967
968// Return true if some equivalent of instruction Inst dominates instruction U.
969bool NewGVN::someEquivalentDominates(const Instruction *Inst,
970 const Instruction *U) const {
971 auto *CC = ValueToClass.lookup(Inst);
972 // This must be an instruction because we are only called from phi nodes
973 // in the case that the value it needs to check against is an instruction.
974
975 // The most likely candiates for dominance are the leader and the next leader.
976 // The leader or nextleader will dominate in all cases where there is an
977 // equivalent that is higher up in the dom tree.
978 // We can't *only* check them, however, because the
979 // dominator tree could have an infinite number of non-dominating siblings
980 // with instructions that are in the right congruence class.
981 // A
982 // B C D E F G
983 // |
984 // H
985 // Instruction U could be in H, with equivalents in every other sibling.
986 // Depending on the rpo order picked, the leader could be the equivalent in
987 // any of these siblings.
988 if (!CC)
989 return false;
990 if (DT->dominates(cast<Instruction>(CC->getLeader()), U))
991 return true;
992 if (CC->getNextLeader().first &&
993 DT->dominates(cast<Instruction>(CC->getNextLeader().first), U))
994 return true;
995 return llvm::any_of(*CC, [&](const Value *Member) {
996 return Member != CC->getLeader() &&
997 DT->dominates(cast<Instruction>(Member), U);
998 });
999}
1000
1001// See if we have a congruence class and leader for this operand, and if so,
1002// return it. Otherwise, return the operand itself.
1003Value *NewGVN::lookupOperandLeader(Value *V) const {
1004 CongruenceClass *CC = ValueToClass.lookup(V);
1005 if (CC) {
1006 // Everything in TOP is represneted by undef, as it can be any value.
1007 // We do have to make sure we get the type right though, so we can't set the
1008 // RepLeader to undef.
1009 if (CC == TOPClass)
1010 return UndefValue::get(V->getType());
1011 return CC->getStoredValue() ? CC->getStoredValue() : CC->getLeader();
1012 }
1013
1014 return V;
1015}
1016
1017const MemoryAccess *NewGVN::lookupMemoryLeader(const MemoryAccess *MA) const {
1018 auto *CC = getMemoryClass(MA);
1019 assert(CC->getMemoryLeader() &&((CC->getMemoryLeader() && "Every MemoryAccess should be mapped to a "
"congruence class with a represenative memory " "access") ? static_cast
<void> (0) : __assert_fail ("CC->getMemoryLeader() && \"Every MemoryAccess should be mapped to a \" \"congruence class with a represenative memory \" \"access\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1022, __PRETTY_FUNCTION__))
1020 "Every MemoryAccess should be mapped to a "((CC->getMemoryLeader() && "Every MemoryAccess should be mapped to a "
"congruence class with a represenative memory " "access") ? static_cast
<void> (0) : __assert_fail ("CC->getMemoryLeader() && \"Every MemoryAccess should be mapped to a \" \"congruence class with a represenative memory \" \"access\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1022, __PRETTY_FUNCTION__))
1021 "congruence class with a represenative memory "((CC->getMemoryLeader() && "Every MemoryAccess should be mapped to a "
"congruence class with a represenative memory " "access") ? static_cast
<void> (0) : __assert_fail ("CC->getMemoryLeader() && \"Every MemoryAccess should be mapped to a \" \"congruence class with a represenative memory \" \"access\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1022, __PRETTY_FUNCTION__))
1022 "access")((CC->getMemoryLeader() && "Every MemoryAccess should be mapped to a "
"congruence class with a represenative memory " "access") ? static_cast
<void> (0) : __assert_fail ("CC->getMemoryLeader() && \"Every MemoryAccess should be mapped to a \" \"congruence class with a represenative memory \" \"access\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1022, __PRETTY_FUNCTION__))
;
1023 return CC->getMemoryLeader();
1024}
1025
1026// Return true if the MemoryAccess is really equivalent to everything. This is
1027// equivalent to the lattice value "TOP" in most lattices. This is the initial
1028// state of all MemoryAccesses.
1029bool NewGVN::isMemoryAccessTop(const MemoryAccess *MA) const {
1030 return getMemoryClass(MA) == TOPClass;
1031}
1032
1033LoadExpression *NewGVN::createLoadExpression(Type *LoadType, Value *PointerOp,
1034 LoadInst *LI,
1035 const MemoryAccess *MA) {
1036 auto *E =
1037 new (ExpressionAllocator) LoadExpression(1, LI, lookupMemoryLeader(MA));
1038 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1039 E->setType(LoadType);
1040
1041 // Give store and loads same opcode so they value number together.
1042 E->setOpcode(0);
1043 E->op_push_back(PointerOp);
1044 if (LI)
1045 E->setAlignment(LI->getAlignment());
1046
1047 // TODO: Value number heap versions. We may be able to discover
1048 // things alias analysis can't on it's own (IE that a store and a
1049 // load have the same value, and thus, it isn't clobbering the load).
1050 return E;
1051}
1052
1053const StoreExpression *NewGVN::createStoreExpression(StoreInst *SI,
1054 const MemoryAccess *MA) {
1055 auto *StoredValueLeader = lookupOperandLeader(SI->getValueOperand());
1056 auto *E = new (ExpressionAllocator)
1057 StoreExpression(SI->getNumOperands(), SI, StoredValueLeader, MA);
1058 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1059 E->setType(SI->getValueOperand()->getType());
1060
1061 // Give store and loads same opcode so they value number together.
1062 E->setOpcode(0);
1063 E->op_push_back(lookupOperandLeader(SI->getPointerOperand()));
1064
1065 // TODO: Value number heap versions. We may be able to discover
1066 // things alias analysis can't on it's own (IE that a store and a
1067 // load have the same value, and thus, it isn't clobbering the load).
1068 return E;
1069}
1070
1071const Expression *NewGVN::performSymbolicStoreEvaluation(Instruction *I) {
1072 // Unlike loads, we never try to eliminate stores, so we do not check if they
1073 // are simple and avoid value numbering them.
1074 auto *SI = cast<StoreInst>(I);
1075 auto *StoreAccess = MSSA->getMemoryAccess(SI);
1076 // Get the expression, if any, for the RHS of the MemoryDef.
1077 const MemoryAccess *StoreRHS = StoreAccess->getDefiningAccess();
1078 if (EnableStoreRefinement)
1079 StoreRHS = MSSAWalker->getClobberingMemoryAccess(StoreAccess);
1080 // If we bypassed the use-def chains, make sure we add a use.
1081 if (StoreRHS != StoreAccess->getDefiningAccess())
1082 addMemoryUsers(StoreRHS, StoreAccess);
1083
1084 StoreRHS = lookupMemoryLeader(StoreRHS);
1085 // If we are defined by ourselves, use the live on entry def.
1086 if (StoreRHS == StoreAccess)
1087 StoreRHS = MSSA->getLiveOnEntryDef();
1088
1089 if (SI->isSimple()) {
1090 // See if we are defined by a previous store expression, it already has a
1091 // value, and it's the same value as our current store. FIXME: Right now, we
1092 // only do this for simple stores, we should expand to cover memcpys, etc.
1093 const auto *LastStore = createStoreExpression(SI, StoreRHS);
1094 const auto *LastCC = ExpressionToClass.lookup(LastStore);
1095 // Basically, check if the congruence class the store is in is defined by a
1096 // store that isn't us, and has the same value. MemorySSA takes care of
1097 // ensuring the store has the same memory state as us already.
1098 // The RepStoredValue gets nulled if all the stores disappear in a class, so
1099 // we don't need to check if the class contains a store besides us.
1100 if (LastCC &&
1101 LastCC->getStoredValue() == lookupOperandLeader(SI->getValueOperand()))
1102 return LastStore;
1103 deleteExpression(LastStore);
1104 // Also check if our value operand is defined by a load of the same memory
1105 // location, and the memory state is the same as it was then (otherwise, it
1106 // could have been overwritten later. See test32 in
1107 // transforms/DeadStoreElimination/simple.ll).
1108 if (auto *LI =
1109 dyn_cast<LoadInst>(lookupOperandLeader(SI->getValueOperand()))) {
1110 if ((lookupOperandLeader(LI->getPointerOperand()) ==
1111 lookupOperandLeader(SI->getPointerOperand())) &&
1112 (lookupMemoryLeader(MSSA->getMemoryAccess(LI)->getDefiningAccess()) ==
1113 StoreRHS))
1114 return createVariableExpression(LI);
1115 }
1116 }
1117
1118 // If the store is not equivalent to anything, value number it as a store that
1119 // produces a unique memory state (instead of using it's MemoryUse, we use
1120 // it's MemoryDef).
1121 return createStoreExpression(SI, StoreAccess);
1122}
1123
1124// See if we can extract the value of a loaded pointer from a load, a store, or
1125// a memory instruction.
1126const Expression *
1127NewGVN::performSymbolicLoadCoercion(Type *LoadType, Value *LoadPtr,
1128 LoadInst *LI, Instruction *DepInst,
1129 MemoryAccess *DefiningAccess) {
1130 assert((!LI || LI->isSimple()) && "Not a simple load")(((!LI || LI->isSimple()) && "Not a simple load") ?
static_cast<void> (0) : __assert_fail ("(!LI || LI->isSimple()) && \"Not a simple load\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1130, __PRETTY_FUNCTION__))
;
1
Within the expansion of the macro 'assert':
a
Assuming 'LI' is null
1131 if (auto *DepSI = dyn_cast<StoreInst>(DepInst)) {
2
Taking false branch
1132 // Can't forward from non-atomic to atomic without violating memory model.
1133 // Also don't need to coerce if they are the same type, we will just
1134 // propogate..
1135 if (LI->isAtomic() > DepSI->isAtomic() ||
1136 LoadType == DepSI->getValueOperand()->getType())
1137 return nullptr;
1138 int Offset = analyzeLoadFromClobberingStore(LoadType, LoadPtr, DepSI, DL);
1139 if (Offset >= 0) {
1140 if (auto *C = dyn_cast<Constant>(
1141 lookupOperandLeader(DepSI->getValueOperand()))) {
1142 DEBUG(dbgs() << "Coercing load from store " << *DepSI << " to constant "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from store " <<
*DepSI << " to constant " << *C << "\n"; }
} while (false)
1143 << *C << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from store " <<
*DepSI << " to constant " << *C << "\n"; }
} while (false)
;
1144 return createConstantExpression(
1145 getConstantStoreValueForLoad(C, Offset, LoadType, DL));
1146 }
1147 }
1148
1149 } else if (LoadInst *DepLI = dyn_cast<LoadInst>(DepInst)) {
3
Assuming 'DepLI' is non-null
4
Taking true branch
1150 // Can't forward from non-atomic to atomic without violating memory model.
1151 if (LI->isAtomic() > DepLI->isAtomic())
5
Called C++ object pointer is null
1152 return nullptr;
1153 int Offset = analyzeLoadFromClobberingLoad(LoadType, LoadPtr, DepLI, DL);
1154 if (Offset >= 0) {
1155 // We can coerce a constant load into a load
1156 if (auto *C = dyn_cast<Constant>(lookupOperandLeader(DepLI)))
1157 if (auto *PossibleConstant =
1158 getConstantLoadValueForLoad(C, Offset, LoadType, DL)) {
1159 DEBUG(dbgs() << "Coercing load from load " << *LI << " to constant "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from load " <<
*LI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
1160 << *PossibleConstant << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from load " <<
*LI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
;
1161 return createConstantExpression(PossibleConstant);
1162 }
1163 }
1164
1165 } else if (MemIntrinsic *DepMI = dyn_cast<MemIntrinsic>(DepInst)) {
1166 int Offset = analyzeLoadFromClobberingMemInst(LoadType, LoadPtr, DepMI, DL);
1167 if (Offset >= 0) {
1168 if (auto *PossibleConstant =
1169 getConstantMemInstValueForLoad(DepMI, Offset, LoadType, DL)) {
1170 DEBUG(dbgs() << "Coercing load from meminst " << *DepMIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from meminst " <<
*DepMI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
1171 << " to constant " << *PossibleConstant << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from meminst " <<
*DepMI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
;
1172 return createConstantExpression(PossibleConstant);
1173 }
1174 }
1175 }
1176
1177 // All of the below are only true if the loaded pointer is produced
1178 // by the dependent instruction.
1179 if (LoadPtr != lookupOperandLeader(DepInst) &&
1180 !AA->isMustAlias(LoadPtr, DepInst))
1181 return nullptr;
1182 // If this load really doesn't depend on anything, then we must be loading an
1183 // undef value. This can happen when loading for a fresh allocation with no
1184 // intervening stores, for example. Note that this is only true in the case
1185 // that the result of the allocation is pointer equal to the load ptr.
1186 if (isa<AllocaInst>(DepInst) || isMallocLikeFn(DepInst, TLI)) {
1187 return createConstantExpression(UndefValue::get(LoadType));
1188 }
1189 // If this load occurs either right after a lifetime begin,
1190 // then the loaded value is undefined.
1191 else if (auto *II = dyn_cast<IntrinsicInst>(DepInst)) {
1192 if (II->getIntrinsicID() == Intrinsic::lifetime_start)
1193 return createConstantExpression(UndefValue::get(LoadType));
1194 }
1195 // If this load follows a calloc (which zero initializes memory),
1196 // then the loaded value is zero
1197 else if (isCallocLikeFn(DepInst, TLI)) {
1198 return createConstantExpression(Constant::getNullValue(LoadType));
1199 }
1200
1201 return nullptr;
1202}
1203
1204const Expression *NewGVN::performSymbolicLoadEvaluation(Instruction *I) {
1205 auto *LI = cast<LoadInst>(I);
1206
1207 // We can eliminate in favor of non-simple loads, but we won't be able to
1208 // eliminate the loads themselves.
1209 if (!LI->isSimple())
1210 return nullptr;
1211
1212 Value *LoadAddressLeader = lookupOperandLeader(LI->getPointerOperand());
1213 // Load of undef is undef.
1214 if (isa<UndefValue>(LoadAddressLeader))
1215 return createConstantExpression(UndefValue::get(LI->getType()));
1216
1217 MemoryAccess *DefiningAccess = MSSAWalker->getClobberingMemoryAccess(I);
1218
1219 if (!MSSA->isLiveOnEntryDef(DefiningAccess)) {
1220 if (auto *MD = dyn_cast<MemoryDef>(DefiningAccess)) {
1221 Instruction *DefiningInst = MD->getMemoryInst();
1222 // If the defining instruction is not reachable, replace with undef.
1223 if (!ReachableBlocks.count(DefiningInst->getParent()))
1224 return createConstantExpression(UndefValue::get(LI->getType()));
1225 // This will handle stores and memory insts. We only do if it the
1226 // defining access has a different type, or it is a pointer produced by
1227 // certain memory operations that cause the memory to have a fixed value
1228 // (IE things like calloc).
1229 if (const auto *CoercionResult =
1230 performSymbolicLoadCoercion(LI->getType(), LoadAddressLeader, LI,
1231 DefiningInst, DefiningAccess))
1232 return CoercionResult;
1233 }
1234 }
1235
1236 const Expression *E = createLoadExpression(LI->getType(), LoadAddressLeader,
1237 LI, DefiningAccess);
1238 return E;
1239}
1240
1241const Expression *
1242NewGVN::performSymbolicPredicateInfoEvaluation(Instruction *I) {
1243 auto *PI = PredInfo->getPredicateInfoFor(I);
1244 if (!PI)
1245 return nullptr;
1246
1247 DEBUG(dbgs() << "Found predicate info from instruction !\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found predicate info from instruction !\n"
; } } while (false)
;
1248
1249 auto *PWC = dyn_cast<PredicateWithCondition>(PI);
1250 if (!PWC)
1251 return nullptr;
1252
1253 auto *CopyOf = I->getOperand(0);
1254 auto *Cond = PWC->Condition;
1255
1256 // If this a copy of the condition, it must be either true or false depending
1257 // on the predicate info type and edge
1258 if (CopyOf == Cond) {
1259 // We should not need to add predicate users because the predicate info is
1260 // already a use of this operand.
1261 if (isa<PredicateAssume>(PI))
1262 return createConstantExpression(ConstantInt::getTrue(Cond->getType()));
1263 if (auto *PBranch = dyn_cast<PredicateBranch>(PI)) {
1264 if (PBranch->TrueEdge)
1265 return createConstantExpression(ConstantInt::getTrue(Cond->getType()));
1266 return createConstantExpression(ConstantInt::getFalse(Cond->getType()));
1267 }
1268 if (auto *PSwitch = dyn_cast<PredicateSwitch>(PI))
1269 return createConstantExpression(cast<Constant>(PSwitch->CaseValue));
1270 }
1271
1272 // Not a copy of the condition, so see what the predicates tell us about this
1273 // value. First, though, we check to make sure the value is actually a copy
1274 // of one of the condition operands. It's possible, in certain cases, for it
1275 // to be a copy of a predicateinfo copy. In particular, if two branch
1276 // operations use the same condition, and one branch dominates the other, we
1277 // will end up with a copy of a copy. This is currently a small deficiency in
1278 // predicateinfo. What will end up happening here is that we will value
1279 // number both copies the same anyway.
1280
1281 // Everything below relies on the condition being a comparison.
1282 auto *Cmp = dyn_cast<CmpInst>(Cond);
1283 if (!Cmp)
1284 return nullptr;
1285
1286 if (CopyOf != Cmp->getOperand(0) && CopyOf != Cmp->getOperand(1)) {
1287 DEBUG(dbgs() << "Copy is not of any condition operands!")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Copy is not of any condition operands!"
; } } while (false)
;
1288 return nullptr;
1289 }
1290 Value *FirstOp = lookupOperandLeader(Cmp->getOperand(0));
1291 Value *SecondOp = lookupOperandLeader(Cmp->getOperand(1));
1292 bool SwappedOps = false;
1293 // Sort the ops
1294 if (shouldSwapOperands(FirstOp, SecondOp)) {
1295 std::swap(FirstOp, SecondOp);
1296 SwappedOps = true;
1297 }
1298 CmpInst::Predicate Predicate =
1299 SwappedOps ? Cmp->getSwappedPredicate() : Cmp->getPredicate();
1300
1301 if (isa<PredicateAssume>(PI)) {
1302 // If the comparison is true when the operands are equal, then we know the
1303 // operands are equal, because assumes must always be true.
1304 if (CmpInst::isTrueWhenEqual(Predicate)) {
1305 addPredicateUsers(PI, I);
1306 return createVariableOrConstant(FirstOp);
1307 }
1308 }
1309 if (const auto *PBranch = dyn_cast<PredicateBranch>(PI)) {
1310 // If we are *not* a copy of the comparison, we may equal to the other
1311 // operand when the predicate implies something about equality of
1312 // operations. In particular, if the comparison is true/false when the
1313 // operands are equal, and we are on the right edge, we know this operation
1314 // is equal to something.
1315 if ((PBranch->TrueEdge && Predicate == CmpInst::ICMP_EQ) ||
1316 (!PBranch->TrueEdge && Predicate == CmpInst::ICMP_NE)) {
1317 addPredicateUsers(PI, I);
1318 return createVariableOrConstant(FirstOp);
1319 }
1320 // Handle the special case of floating point.
1321 if (((PBranch->TrueEdge && Predicate == CmpInst::FCMP_OEQ) ||
1322 (!PBranch->TrueEdge && Predicate == CmpInst::FCMP_UNE)) &&
1323 isa<ConstantFP>(FirstOp) && !cast<ConstantFP>(FirstOp)->isZero()) {
1324 addPredicateUsers(PI, I);
1325 return createConstantExpression(cast<Constant>(FirstOp));
1326 }
1327 }
1328 return nullptr;
1329}
1330
1331// Evaluate read only and pure calls, and create an expression result.
1332const Expression *NewGVN::performSymbolicCallEvaluation(Instruction *I) {
1333 auto *CI = cast<CallInst>(I);
1334 if (auto *II = dyn_cast<IntrinsicInst>(I)) {
1335 // Instrinsics with the returned attribute are copies of arguments.
1336 if (auto *ReturnedValue = II->getReturnedArgOperand()) {
1337 if (II->getIntrinsicID() == Intrinsic::ssa_copy)
1338 if (const auto *Result = performSymbolicPredicateInfoEvaluation(I))
1339 return Result;
1340 return createVariableOrConstant(ReturnedValue);
1341 }
1342 }
1343 if (AA->doesNotAccessMemory(CI)) {
1344 return createCallExpression(CI, TOPClass->getMemoryLeader());
1345 } else if (AA->onlyReadsMemory(CI)) {
1346 MemoryAccess *DefiningAccess = MSSAWalker->getClobberingMemoryAccess(CI);
1347 return createCallExpression(CI, DefiningAccess);
1348 }
1349 return nullptr;
1350}
1351
1352// Retrieve the memory class for a given MemoryAccess.
1353CongruenceClass *NewGVN::getMemoryClass(const MemoryAccess *MA) const {
1354
1355 auto *Result = MemoryAccessToClass.lookup(MA);
1356 assert(Result && "Should have found memory class")((Result && "Should have found memory class") ? static_cast
<void> (0) : __assert_fail ("Result && \"Should have found memory class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1356, __PRETTY_FUNCTION__))
;
1357 return Result;
1358}
1359
1360// Update the MemoryAccess equivalence table to say that From is equal to To,
1361// and return true if this is different from what already existed in the table.
1362bool NewGVN::setMemoryClass(const MemoryAccess *From,
1363 CongruenceClass *NewClass) {
1364 assert(NewClass &&((NewClass && "Every MemoryAccess should be getting mapped to a non-null class"
) ? static_cast<void> (0) : __assert_fail ("NewClass && \"Every MemoryAccess should be getting mapped to a non-null class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1365, __PRETTY_FUNCTION__))
1365 "Every MemoryAccess should be getting mapped to a non-null class")((NewClass && "Every MemoryAccess should be getting mapped to a non-null class"
) ? static_cast<void> (0) : __assert_fail ("NewClass && \"Every MemoryAccess should be getting mapped to a non-null class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1365, __PRETTY_FUNCTION__))
;
1366 DEBUG(dbgs() << "Setting " << *From)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Setting " << *From; } } while
(false)
;
1367 DEBUG(dbgs() << " equivalent to congruence class ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " equivalent to congruence class "
; } } while (false)
;
1368 DEBUG(dbgs() << NewClass->getID() << " with current MemoryAccess leader ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << NewClass->getID() << " with current MemoryAccess leader "
; } } while (false)
;
1369 DEBUG(dbgs() << *NewClass->getMemoryLeader())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << *NewClass->getMemoryLeader()
; } } while (false)
;
1370 DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "\n"; } } while (false)
;
1371
1372 auto LookupResult = MemoryAccessToClass.find(From);
1373 bool Changed = false;
1374 // If it's already in the table, see if the value changed.
1375 if (LookupResult != MemoryAccessToClass.end()) {
1376 auto *OldClass = LookupResult->second;
1377 if (OldClass != NewClass) {
1378 // If this is a phi, we have to handle memory member updates.
1379 if (auto *MP = dyn_cast<MemoryPhi>(From)) {
1380 OldClass->memory_erase(MP);
1381 NewClass->memory_insert(MP);
1382 // This may have killed the class if it had no non-memory members
1383 if (OldClass->getMemoryLeader() == From) {
1384 if (OldClass->memory_empty()) {
1385 OldClass->setMemoryLeader(nullptr);
1386 } else {
1387 OldClass->setMemoryLeader(getNextMemoryLeader(OldClass));
1388 DEBUG(dbgs() << "Memory class leader change for class "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of a memory member "
<< *From << "\n"; } } while (false)
1389 << OldClass->getID() << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of a memory member "
<< *From << "\n"; } } while (false)
1390 << *OldClass->getMemoryLeader()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of a memory member "
<< *From << "\n"; } } while (false)
1391 << " due to removal of a memory member " << *Fromdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of a memory member "
<< *From << "\n"; } } while (false)
1392 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of a memory member "
<< *From << "\n"; } } while (false)
;
1393 markMemoryLeaderChangeTouched(OldClass);
1394 }
1395 }
1396 }
1397 // It wasn't equivalent before, and now it is.
1398 LookupResult->second = NewClass;
1399 Changed = true;
1400 }
1401 }
1402
1403 return Changed;
1404}
1405
1406// Determine if a phi is cycle-free. That means the values in the phi don't
1407// depend on any expressions that can change value as a result of the phi.
1408// For example, a non-cycle free phi would be v = phi(0, v+1).
1409bool NewGVN::isCycleFree(const PHINode *PN) {
1410 // In order to compute cycle-freeness, we do SCC finding on the phi, and see
1411 // what kind of SCC it ends up in. If it is a singleton, it is cycle-free.
1412 // If it is not in a singleton, it is only cycle free if the other members are
1413 // all phi nodes (as they do not compute anything, they are copies). TODO:
1414 // There are likely a few other intrinsics or expressions that could be
1415 // included here, but this happens so infrequently already that it is not
1416 // likely to be worth it.
1417 auto PCS = PhiCycleState.lookup(PN);
1418 if (PCS == PCS_Unknown) {
1419 SCCFinder.Start(PN);
1420 auto &SCC = SCCFinder.getComponentFor(PN);
1421 // It's cycle free if it's size 1 or or the SCC is *only* phi nodes.
1422 if (SCC.size() == 1)
1423 PhiCycleState.insert({PN, PCS_CycleFree});
1424 else {
1425 bool AllPhis =
1426 llvm::all_of(SCC, [](const Value *V) { return isa<PHINode>(V); });
1427 PCS = AllPhis ? PCS_CycleFree : PCS_Cycle;
1428 for (auto *Member : SCC)
1429 if (auto *MemberPhi = dyn_cast<PHINode>(Member))
1430 PhiCycleState.insert({MemberPhi, PCS});
1431 }
1432 }
1433 if (PCS == PCS_Cycle)
1434 return false;
1435 return true;
1436}
1437
1438// Evaluate PHI nodes symbolically, and create an expression result.
1439const Expression *NewGVN::performSymbolicPHIEvaluation(Instruction *I) {
1440 // True if one of the incoming phi edges is a backedge.
1441 bool HasBackedge = false;
1442 // All constant tracks the state of whether all the *original* phi operands
1443 // were constant.
1444 // This is really shorthand for "this phi cannot cycle due to forward
1445 // propagation", as any
1446 // change in value of the phi is guaranteed not to later change the value of
1447 // the phi.
1448 // IE it can't be v = phi(undef, v+1)
1449 bool AllConstant = true;
1450 auto *E =
1451 cast<PHIExpression>(createPHIExpression(I, HasBackedge, AllConstant));
1452 // We match the semantics of SimplifyPhiNode from InstructionSimplify here.
1453
1454 // See if all arguaments are the same.
1455 // We track if any were undef because they need special handling.
1456 bool HasUndef = false;
1457 auto Filtered = make_filter_range(E->operands(), [&](const Value *Arg) {
1458 if (Arg == I)
1459 return false;
1460 if (isa<UndefValue>(Arg)) {
1461 HasUndef = true;
1462 return false;
1463 }
1464 return true;
1465 });
1466 // If we are left with no operands, it's undef
1467 if (Filtered.begin() == Filtered.end()) {
1468 DEBUG(dbgs() << "Simplified PHI node " << *I << " to undef"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified PHI node " <<
*I << " to undef" << "\n"; } } while (false)
1469 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified PHI node " <<
*I << " to undef" << "\n"; } } while (false)
;
1470 deleteExpression(E);
1471 return createConstantExpression(UndefValue::get(I->getType()));
1472 }
1473 unsigned NumOps = 0;
1474 Value *AllSameValue = *(Filtered.begin());
1475 ++Filtered.begin();
1476 // Can't use std::equal here, sadly, because filter.begin moves.
1477 if (llvm::all_of(Filtered, [AllSameValue, &NumOps](const Value *V) {
1478 ++NumOps;
1479 return V == AllSameValue;
1480 })) {
1481 // In LLVM's non-standard representation of phi nodes, it's possible to have
1482 // phi nodes with cycles (IE dependent on other phis that are .... dependent
1483 // on the original phi node), especially in weird CFG's where some arguments
1484 // are unreachable, or uninitialized along certain paths. This can cause
1485 // infinite loops during evaluation. We work around this by not trying to
1486 // really evaluate them independently, but instead using a variable
1487 // expression to say if one is equivalent to the other.
1488 // We also special case undef, so that if we have an undef, we can't use the
1489 // common value unless it dominates the phi block.
1490 if (HasUndef) {
1491 // If we have undef and at least one other value, this is really a
1492 // multivalued phi, and we need to know if it's cycle free in order to
1493 // evaluate whether we can ignore the undef. The other parts of this are
1494 // just shortcuts. If there is no backedge, or all operands are
1495 // constants, or all operands are ignored but the undef, it also must be
1496 // cycle free.
1497 if (!AllConstant && HasBackedge && NumOps > 0 &&
1498 !isa<UndefValue>(AllSameValue) && !isCycleFree(cast<PHINode>(I)))
1499 return E;
1500
1501 // Only have to check for instructions
1502 if (auto *AllSameInst = dyn_cast<Instruction>(AllSameValue))
1503 if (!someEquivalentDominates(AllSameInst, I))
1504 return E;
1505 }
1506
1507 NumGVNPhisAllSame++;
1508 DEBUG(dbgs() << "Simplified PHI node " << *I << " to " << *AllSameValuedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified PHI node " <<
*I << " to " << *AllSameValue << "\n"; } }
while (false)
1509 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified PHI node " <<
*I << " to " << *AllSameValue << "\n"; } }
while (false)
;
1510 deleteExpression(E);
1511 return createVariableOrConstant(AllSameValue);
1512 }
1513 return E;
1514}
1515
1516const Expression *NewGVN::performSymbolicAggrValueEvaluation(Instruction *I) {
1517 if (auto *EI = dyn_cast<ExtractValueInst>(I)) {
1518 auto *II = dyn_cast<IntrinsicInst>(EI->getAggregateOperand());
1519 if (II && EI->getNumIndices() == 1 && *EI->idx_begin() == 0) {
1520 unsigned Opcode = 0;
1521 // EI might be an extract from one of our recognised intrinsics. If it
1522 // is we'll synthesize a semantically equivalent expression instead on
1523 // an extract value expression.
1524 switch (II->getIntrinsicID()) {
1525 case Intrinsic::sadd_with_overflow:
1526 case Intrinsic::uadd_with_overflow:
1527 Opcode = Instruction::Add;
1528 break;
1529 case Intrinsic::ssub_with_overflow:
1530 case Intrinsic::usub_with_overflow:
1531 Opcode = Instruction::Sub;
1532 break;
1533 case Intrinsic::smul_with_overflow:
1534 case Intrinsic::umul_with_overflow:
1535 Opcode = Instruction::Mul;
1536 break;
1537 default:
1538 break;
1539 }
1540
1541 if (Opcode != 0) {
1542 // Intrinsic recognized. Grab its args to finish building the
1543 // expression.
1544 assert(II->getNumArgOperands() == 2 &&((II->getNumArgOperands() == 2 && "Expect two args for recognised intrinsics."
) ? static_cast<void> (0) : __assert_fail ("II->getNumArgOperands() == 2 && \"Expect two args for recognised intrinsics.\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1545, __PRETTY_FUNCTION__))
1545 "Expect two args for recognised intrinsics.")((II->getNumArgOperands() == 2 && "Expect two args for recognised intrinsics."
) ? static_cast<void> (0) : __assert_fail ("II->getNumArgOperands() == 2 && \"Expect two args for recognised intrinsics.\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1545, __PRETTY_FUNCTION__))
;
1546 return createBinaryExpression(
1547 Opcode, EI->getType(), II->getArgOperand(0), II->getArgOperand(1));
1548 }
1549 }
1550 }
1551
1552 return createAggregateValueExpression(I);
1553}
1554const Expression *NewGVN::performSymbolicCmpEvaluation(Instruction *I) {
1555 auto *CI = dyn_cast<CmpInst>(I);
1556 // See if our operands are equal to those of a previous predicate, and if so,
1557 // if it implies true or false.
1558 auto Op0 = lookupOperandLeader(CI->getOperand(0));
1559 auto Op1 = lookupOperandLeader(CI->getOperand(1));
1560 auto OurPredicate = CI->getPredicate();
1561 if (shouldSwapOperands(Op0, Op1)) {
1562 std::swap(Op0, Op1);
1563 OurPredicate = CI->getSwappedPredicate();
1564 }
1565
1566 // Avoid processing the same info twice
1567 const PredicateBase *LastPredInfo = nullptr;
1568 // See if we know something about the comparison itself, like it is the target
1569 // of an assume.
1570 auto *CmpPI = PredInfo->getPredicateInfoFor(I);
1571 if (dyn_cast_or_null<PredicateAssume>(CmpPI))
1572 return createConstantExpression(ConstantInt::getTrue(CI->getType()));
1573
1574 if (Op0 == Op1) {
1575 // This condition does not depend on predicates, no need to add users
1576 if (CI->isTrueWhenEqual())
1577 return createConstantExpression(ConstantInt::getTrue(CI->getType()));
1578 else if (CI->isFalseWhenEqual())
1579 return createConstantExpression(ConstantInt::getFalse(CI->getType()));
1580 }
1581
1582 // NOTE: Because we are comparing both operands here and below, and using
1583 // previous comparisons, we rely on fact that predicateinfo knows to mark
1584 // comparisons that use renamed operands as users of the earlier comparisons.
1585 // It is *not* enough to just mark predicateinfo renamed operands as users of
1586 // the earlier comparisons, because the *other* operand may have changed in a
1587 // previous iteration.
1588 // Example:
1589 // icmp slt %a, %b
1590 // %b.0 = ssa.copy(%b)
1591 // false branch:
1592 // icmp slt %c, %b.0
1593
1594 // %c and %a may start out equal, and thus, the code below will say the second
1595 // %icmp is false. c may become equal to something else, and in that case the
1596 // %second icmp *must* be reexamined, but would not if only the renamed
1597 // %operands are considered users of the icmp.
1598
1599 // *Currently* we only check one level of comparisons back, and only mark one
1600 // level back as touched when changes appen . If you modify this code to look
1601 // back farther through comparisons, you *must* mark the appropriate
1602 // comparisons as users in PredicateInfo.cpp, or you will cause bugs. See if
1603 // we know something just from the operands themselves
1604
1605 // See if our operands have predicate info, so that we may be able to derive
1606 // something from a previous comparison.
1607 for (const auto &Op : CI->operands()) {
1608 auto *PI = PredInfo->getPredicateInfoFor(Op);
1609 if (const auto *PBranch = dyn_cast_or_null<PredicateBranch>(PI)) {
1610 if (PI == LastPredInfo)
1611 continue;
1612 LastPredInfo = PI;
1613
1614 // TODO: Along the false edge, we may know more things too, like icmp of
1615 // same operands is false.
1616 // TODO: We only handle actual comparison conditions below, not and/or.
1617 auto *BranchCond = dyn_cast<CmpInst>(PBranch->Condition);
1618 if (!BranchCond)
1619 continue;
1620 auto *BranchOp0 = lookupOperandLeader(BranchCond->getOperand(0));
1621 auto *BranchOp1 = lookupOperandLeader(BranchCond->getOperand(1));
1622 auto BranchPredicate = BranchCond->getPredicate();
1623 if (shouldSwapOperands(BranchOp0, BranchOp1)) {
1624 std::swap(BranchOp0, BranchOp1);
1625 BranchPredicate = BranchCond->getSwappedPredicate();
1626 }
1627 if (BranchOp0 == Op0 && BranchOp1 == Op1) {
1628 if (PBranch->TrueEdge) {
1629 // If we know the previous predicate is true and we are in the true
1630 // edge then we may be implied true or false.
1631 if (CmpInst::isImpliedTrueByMatchingCmp(OurPredicate,
1632 BranchPredicate)) {
1633 addPredicateUsers(PI, I);
1634 return createConstantExpression(
1635 ConstantInt::getTrue(CI->getType()));
1636 }
1637
1638 if (CmpInst::isImpliedFalseByMatchingCmp(OurPredicate,
1639 BranchPredicate)) {
1640 addPredicateUsers(PI, I);
1641 return createConstantExpression(
1642 ConstantInt::getFalse(CI->getType()));
1643 }
1644
1645 } else {
1646 // Just handle the ne and eq cases, where if we have the same
1647 // operands, we may know something.
1648 if (BranchPredicate == OurPredicate) {
1649 addPredicateUsers(PI, I);
1650 // Same predicate, same ops,we know it was false, so this is false.
1651 return createConstantExpression(
1652 ConstantInt::getFalse(CI->getType()));
1653 } else if (BranchPredicate ==
1654 CmpInst::getInversePredicate(OurPredicate)) {
1655 addPredicateUsers(PI, I);
1656 // Inverse predicate, we know the other was false, so this is true.
1657 return createConstantExpression(
1658 ConstantInt::getTrue(CI->getType()));
1659 }
1660 }
1661 }
1662 }
1663 }
1664 // Create expression will take care of simplifyCmpInst
1665 return createExpression(I);
1666}
1667
1668// Substitute and symbolize the value before value numbering.
1669const Expression *NewGVN::performSymbolicEvaluation(Value *V) {
1670 const Expression *E = nullptr;
1671 if (auto *C = dyn_cast<Constant>(V))
1672 E = createConstantExpression(C);
1673 else if (isa<Argument>(V) || isa<GlobalVariable>(V)) {
1674 E = createVariableExpression(V);
1675 } else {
1676 // TODO: memory intrinsics.
1677 // TODO: Some day, we should do the forward propagation and reassociation
1678 // parts of the algorithm.
1679 auto *I = cast<Instruction>(V);
1680 switch (I->getOpcode()) {
1681 case Instruction::ExtractValue:
1682 case Instruction::InsertValue:
1683 E = performSymbolicAggrValueEvaluation(I);
1684 break;
1685 case Instruction::PHI:
1686 E = performSymbolicPHIEvaluation(I);
1687 break;
1688 case Instruction::Call:
1689 E = performSymbolicCallEvaluation(I);
1690 break;
1691 case Instruction::Store:
1692 E = performSymbolicStoreEvaluation(I);
1693 break;
1694 case Instruction::Load:
1695 E = performSymbolicLoadEvaluation(I);
1696 break;
1697 case Instruction::BitCast: {
1698 E = createExpression(I);
1699 } break;
1700 case Instruction::ICmp:
1701 case Instruction::FCmp: {
1702 E = performSymbolicCmpEvaluation(I);
1703 } break;
1704 case Instruction::Add:
1705 case Instruction::FAdd:
1706 case Instruction::Sub:
1707 case Instruction::FSub:
1708 case Instruction::Mul:
1709 case Instruction::FMul:
1710 case Instruction::UDiv:
1711 case Instruction::SDiv:
1712 case Instruction::FDiv:
1713 case Instruction::URem:
1714 case Instruction::SRem:
1715 case Instruction::FRem:
1716 case Instruction::Shl:
1717 case Instruction::LShr:
1718 case Instruction::AShr:
1719 case Instruction::And:
1720 case Instruction::Or:
1721 case Instruction::Xor:
1722 case Instruction::Trunc:
1723 case Instruction::ZExt:
1724 case Instruction::SExt:
1725 case Instruction::FPToUI:
1726 case Instruction::FPToSI:
1727 case Instruction::UIToFP:
1728 case Instruction::SIToFP:
1729 case Instruction::FPTrunc:
1730 case Instruction::FPExt:
1731 case Instruction::PtrToInt:
1732 case Instruction::IntToPtr:
1733 case Instruction::Select:
1734 case Instruction::ExtractElement:
1735 case Instruction::InsertElement:
1736 case Instruction::ShuffleVector:
1737 case Instruction::GetElementPtr:
1738 E = createExpression(I);
1739 break;
1740 default:
1741 return nullptr;
1742 }
1743 }
1744 return E;
1745}
1746
1747void NewGVN::markUsersTouched(Value *V) {
1748 // Now mark the users as touched.
1749 for (auto *User : V->users()) {
1750 assert(isa<Instruction>(User) && "Use of value not within an instruction?")((isa<Instruction>(User) && "Use of value not within an instruction?"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(User) && \"Use of value not within an instruction?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1750, __PRETTY_FUNCTION__))
;
1751 TouchedInstructions.set(InstrToDFSNum(User));
1752 }
1753}
1754
1755void NewGVN::addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) {
1756 DEBUG(dbgs() << "Adding memory user " << *U << " to " << *To << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Adding memory user " << *
U << " to " << *To << "\n"; } } while (false
)
;
1757 MemoryToUsers[To].insert(U);
1758}
1759
1760void NewGVN::markMemoryDefTouched(const MemoryAccess *MA) {
1761 TouchedInstructions.set(MemoryToDFSNum(MA));
1762}
1763
1764void NewGVN::markMemoryUsersTouched(const MemoryAccess *MA) {
1765 if (isa<MemoryUse>(MA))
1766 return;
1767 for (auto U : MA->users())
1768 TouchedInstructions.set(MemoryToDFSNum(U));
1769 const auto Result = MemoryToUsers.find(MA);
1770 if (Result != MemoryToUsers.end()) {
1771 for (auto *User : Result->second)
1772 TouchedInstructions.set(MemoryToDFSNum(User));
1773 MemoryToUsers.erase(Result);
1774 }
1775}
1776
1777// Add I to the set of users of a given predicate.
1778void NewGVN::addPredicateUsers(const PredicateBase *PB, Instruction *I) {
1779 if (auto *PBranch = dyn_cast<PredicateBranch>(PB))
1780 PredicateToUsers[PBranch->Condition].insert(I);
1781 else if (auto *PAssume = dyn_cast<PredicateBranch>(PB))
1782 PredicateToUsers[PAssume->Condition].insert(I);
1783}
1784
1785// Touch all the predicates that depend on this instruction.
1786void NewGVN::markPredicateUsersTouched(Instruction *I) {
1787 const auto Result = PredicateToUsers.find(I);
1788 if (Result != PredicateToUsers.end()) {
1789 for (auto *User : Result->second)
1790 TouchedInstructions.set(InstrToDFSNum(User));
1791 PredicateToUsers.erase(Result);
1792 }
1793}
1794
1795// Mark users affected by a memory leader change.
1796void NewGVN::markMemoryLeaderChangeTouched(CongruenceClass *CC) {
1797 for (auto M : CC->memory())
1798 markMemoryDefTouched(M);
1799}
1800
1801// Touch the instructions that need to be updated after a congruence class has a
1802// leader change, and mark changed values.
1803void NewGVN::markValueLeaderChangeTouched(CongruenceClass *CC) {
1804 for (auto M : *CC) {
1805 if (auto *I = dyn_cast<Instruction>(M))
1806 TouchedInstructions.set(InstrToDFSNum(I));
1807 LeaderChanges.insert(M);
1808 }
1809}
1810
1811// Give a range of things that have instruction DFS numbers, this will return
1812// the member of the range with the smallest dfs number.
1813template <class T, class Range>
1814T *NewGVN::getMinDFSOfRange(const Range &R) const {
1815 std::pair<T *, unsigned> MinDFS = {nullptr, ~0U};
1816 for (const auto X : R) {
1817 auto DFSNum = InstrToDFSNum(X);
1818 if (DFSNum < MinDFS.second)
1819 MinDFS = {X, DFSNum};
1820 }
1821 return MinDFS.first;
1822}
1823
1824// This function returns the MemoryAccess that should be the next leader of
1825// congruence class CC, under the assumption that the current leader is going to
1826// disappear.
1827const MemoryAccess *NewGVN::getNextMemoryLeader(CongruenceClass *CC) const {
1828 // TODO: If this ends up to slow, we can maintain a next memory leader like we
1829 // do for regular leaders.
1830 // Make sure there will be a leader to find
1831 assert((CC->getStoreCount() > 0 || !CC->memory_empty()) &&(((CC->getStoreCount() > 0 || !CC->memory_empty()) &&
"Can't get next leader if there is none") ? static_cast<void
> (0) : __assert_fail ("(CC->getStoreCount() > 0 || !CC->memory_empty()) && \"Can't get next leader if there is none\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1832, __PRETTY_FUNCTION__))
1832 "Can't get next leader if there is none")(((CC->getStoreCount() > 0 || !CC->memory_empty()) &&
"Can't get next leader if there is none") ? static_cast<void
> (0) : __assert_fail ("(CC->getStoreCount() > 0 || !CC->memory_empty()) && \"Can't get next leader if there is none\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1832, __PRETTY_FUNCTION__))
;
1833 if (CC->getStoreCount() > 0) {
1834 if (auto *NL = dyn_cast_or_null<StoreInst>(CC->getNextLeader().first))
1835 return MSSA->getMemoryAccess(NL);
1836 // Find the store with the minimum DFS number.
1837 auto *V = getMinDFSOfRange<Value>(make_filter_range(
1838 *CC, [&](const Value *V) { return isa<StoreInst>(V); }));
1839 return MSSA->getMemoryAccess(cast<StoreInst>(V));
1840 }
1841 assert(CC->getStoreCount() == 0)((CC->getStoreCount() == 0) ? static_cast<void> (0) :
__assert_fail ("CC->getStoreCount() == 0", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1841, __PRETTY_FUNCTION__))
;
1842
1843 // Given our assertion, hitting this part must mean
1844 // !OldClass->memory_empty()
1845 if (CC->memory_size() == 1)
1846 return *CC->memory_begin();
1847 return getMinDFSOfRange<const MemoryPhi>(CC->memory());
1848}
1849
1850// This function returns the next value leader of a congruence class, under the
1851// assumption that the current leader is going away. This should end up being
1852// the next most dominating member.
1853Value *NewGVN::getNextValueLeader(CongruenceClass *CC) const {
1854 // We don't need to sort members if there is only 1, and we don't care about
1855 // sorting the TOP class because everything either gets out of it or is
1856 // unreachable.
1857
1858 if (CC->size() == 1 || CC == TOPClass) {
1859 return *(CC->begin());
1860 } else if (CC->getNextLeader().first) {
1861 ++NumGVNAvoidedSortedLeaderChanges;
1862 return CC->getNextLeader().first;
1863 } else {
1864 ++NumGVNSortedLeaderChanges;
1865 // NOTE: If this ends up to slow, we can maintain a dual structure for
1866 // member testing/insertion, or keep things mostly sorted, and sort only
1867 // here, or use SparseBitVector or ....
1868 return getMinDFSOfRange<Value>(*CC);
1869 }
1870}
1871
1872// Move a MemoryAccess, currently in OldClass, to NewClass, including updates to
1873// the memory members, etc for the move.
1874//
1875// The invariants of this function are:
1876//
1877// I must be moving to NewClass from OldClass The StoreCount of OldClass and
1878// NewClass is expected to have been updated for I already if it is is a store.
1879// The OldClass memory leader has not been updated yet if I was the leader.
1880void NewGVN::moveMemoryToNewCongruenceClass(Instruction *I,
1881 MemoryAccess *InstMA,
1882 CongruenceClass *OldClass,
1883 CongruenceClass *NewClass) {
1884 // If the leader is I, and we had a represenative MemoryAccess, it should
1885 // be the MemoryAccess of OldClass.
1886 assert((!InstMA || !OldClass->getMemoryLeader() ||(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || OldClass->getMemoryLeader() == InstMA)
&& "Representative MemoryAccess mismatch") ? static_cast
<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || OldClass->getMemoryLeader() == InstMA) && \"Representative MemoryAccess mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1889, __PRETTY_FUNCTION__))
1887 OldClass->getLeader() != I ||(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || OldClass->getMemoryLeader() == InstMA)
&& "Representative MemoryAccess mismatch") ? static_cast
<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || OldClass->getMemoryLeader() == InstMA) && \"Representative MemoryAccess mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1889, __PRETTY_FUNCTION__))
1888 OldClass->getMemoryLeader() == InstMA) &&(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || OldClass->getMemoryLeader() == InstMA)
&& "Representative MemoryAccess mismatch") ? static_cast
<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || OldClass->getMemoryLeader() == InstMA) && \"Representative MemoryAccess mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1889, __PRETTY_FUNCTION__))
1889 "Representative MemoryAccess mismatch")(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || OldClass->getMemoryLeader() == InstMA)
&& "Representative MemoryAccess mismatch") ? static_cast
<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || OldClass->getMemoryLeader() == InstMA) && \"Representative MemoryAccess mismatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1889, __PRETTY_FUNCTION__))
;
1890 // First, see what happens to the new class
1891 if (!NewClass->getMemoryLeader()) {
1892 // Should be a new class, or a store becoming a leader of a new class.
1893 assert(NewClass->size() == 1 ||((NewClass->size() == 1 || (isa<StoreInst>(I) &&
NewClass->getStoreCount() == 1)) ? static_cast<void>
(0) : __assert_fail ("NewClass->size() == 1 || (isa<StoreInst>(I) && NewClass->getStoreCount() == 1)"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1894, __PRETTY_FUNCTION__))
1894 (isa<StoreInst>(I) && NewClass->getStoreCount() == 1))((NewClass->size() == 1 || (isa<StoreInst>(I) &&
NewClass->getStoreCount() == 1)) ? static_cast<void>
(0) : __assert_fail ("NewClass->size() == 1 || (isa<StoreInst>(I) && NewClass->getStoreCount() == 1)"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1894, __PRETTY_FUNCTION__))
;
1895 NewClass->setMemoryLeader(InstMA);
1896 // Mark it touched if we didn't just create a singleton
1897 DEBUG(dbgs() << "Memory class leader change for class " << NewClass->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< NewClass->getID() << " due to new memory instruction becoming leader\n"
; } } while (false)
1898 << " due to new memory instruction becoming leader\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< NewClass->getID() << " due to new memory instruction becoming leader\n"
; } } while (false)
;
1899 markMemoryLeaderChangeTouched(NewClass);
1900 }
1901 setMemoryClass(InstMA, NewClass);
1902 // Now, fixup the old class if necessary
1903 if (OldClass->getMemoryLeader() == InstMA) {
1904 if (OldClass->getStoreCount() != 0 || !OldClass->memory_empty()) {
1905 OldClass->setMemoryLeader(getNextMemoryLeader(OldClass));
1906 DEBUG(dbgs() << "Memory class leader change for class "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of old leader "
<< *InstMA << "\n"; } } while (false)
1907 << OldClass->getID() << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of old leader "
<< *InstMA << "\n"; } } while (false)
1908 << *OldClass->getMemoryLeader()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of old leader "
<< *InstMA << "\n"; } } while (false)
1909 << " due to removal of old leader " << *InstMA << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory class leader change for class "
<< OldClass->getID() << " to " << *OldClass
->getMemoryLeader() << " due to removal of old leader "
<< *InstMA << "\n"; } } while (false)
;
1910 markMemoryLeaderChangeTouched(OldClass);
1911 } else
1912 OldClass->setMemoryLeader(nullptr);
1913 }
1914}
1915
1916// Move a value, currently in OldClass, to be part of NewClass
1917// Update OldClass and NewClass for the move (including changing leaders, etc).
1918void NewGVN::moveValueToNewCongruenceClass(Instruction *I, const Expression *E,
1919 CongruenceClass *OldClass,
1920 CongruenceClass *NewClass) {
1921 if (I == OldClass->getNextLeader().first)
1922 OldClass->resetNextLeader();
1923
1924 // It's possible, though unlikely, for us to discover equivalences such
1925 // that the current leader does not dominate the old one.
1926 // This statistic tracks how often this happens.
1927 // We assert on phi nodes when this happens, currently, for debugging, because
1928 // we want to make sure we name phi node cycles properly.
1929 if (isa<Instruction>(NewClass->getLeader()) && NewClass->getLeader() &&
1930 I != NewClass->getLeader()) {
1931 auto *IBB = I->getParent();
1932 auto *NCBB = cast<Instruction>(NewClass->getLeader())->getParent();
1933 bool Dominated =
1934 IBB == NCBB && InstrToDFSNum(I) < InstrToDFSNum(NewClass->getLeader());
1935 Dominated = Dominated || DT->properlyDominates(IBB, NCBB);
1936 if (Dominated) {
1937 ++NumGVNNotMostDominatingLeader;
1938 assert(((!isa<PHINode>(I) && "New class for instruction should not be dominated by instruction"
) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(I) && \"New class for instruction should not be dominated by instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1940, __PRETTY_FUNCTION__))
1939 !isa<PHINode>(I) &&((!isa<PHINode>(I) && "New class for instruction should not be dominated by instruction"
) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(I) && \"New class for instruction should not be dominated by instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1940, __PRETTY_FUNCTION__))
1940 "New class for instruction should not be dominated by instruction")((!isa<PHINode>(I) && "New class for instruction should not be dominated by instruction"
) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(I) && \"New class for instruction should not be dominated by instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1940, __PRETTY_FUNCTION__))
;
1941 }
1942 }
1943
1944 if (NewClass->getLeader() != I)
1945 NewClass->addPossibleNextLeader({I, InstrToDFSNum(I)});
1946
1947 OldClass->erase(I);
1948 NewClass->insert(I);
1949 // Handle our special casing of stores.
1950 if (auto *SI = dyn_cast<StoreInst>(I)) {
1951 OldClass->decStoreCount();
1952 // Okay, so when do we want to make a store a leader of a class?
1953 // If we have a store defined by an earlier load, we want the earlier load
1954 // to lead the class.
1955 // If we have a store defined by something else, we want the store to lead
1956 // the class so everything else gets the "something else" as a value.
1957 // If we have a store as the single member of the class, we want the store
1958 // as the leader
1959 if (NewClass->getStoreCount() == 0 && !NewClass->getStoredValue()) {
1960 // If it's a store expression we are using, it means we are not equivalent
1961 // to something earlier.
1962 if (isa<StoreExpression>(E)) {
1963 assert(lookupOperandLeader(SI->getValueOperand()) !=((lookupOperandLeader(SI->getValueOperand()) != NewClass->
getLeader()) ? static_cast<void> (0) : __assert_fail ("lookupOperandLeader(SI->getValueOperand()) != NewClass->getLeader()"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1964, __PRETTY_FUNCTION__))
1964 NewClass->getLeader())((lookupOperandLeader(SI->getValueOperand()) != NewClass->
getLeader()) ? static_cast<void> (0) : __assert_fail ("lookupOperandLeader(SI->getValueOperand()) != NewClass->getLeader()"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 1964, __PRETTY_FUNCTION__))
;
1965 NewClass->setStoredValue(lookupOperandLeader(SI->getValueOperand()));
1966 markValueLeaderChangeTouched(NewClass);
1967 // Shift the new class leader to be the store
1968 DEBUG(dbgs() << "Changing leader of congruence class "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Changing leader of congruence class "
<< NewClass->getID() << " from " << *NewClass
->getLeader() << " to " << *SI << " because store joined class\n"
; } } while (false)
1969 << NewClass->getID() << " from " << *NewClass->getLeader()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Changing leader of congruence class "
<< NewClass->getID() << " from " << *NewClass
->getLeader() << " to " << *SI << " because store joined class\n"
; } } while (false)
1970 << " to " << *SI << " because store joined class\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Changing leader of congruence class "
<< NewClass->getID() << " from " << *NewClass
->getLeader() << " to " << *SI << " because store joined class\n"
; } } while (false)
;
1971 // If we changed the leader, we have to mark it changed because we don't
1972 // know what it will do to symbolic evlauation.
1973 NewClass->setLeader(SI);
1974 }
1975 // We rely on the code below handling the MemoryAccess change.
1976 }
1977 NewClass->incStoreCount();
1978 }
1979 // True if there is no memory instructions left in a class that had memory
1980 // instructions before.
1981
1982 // If it's not a memory use, set the MemoryAccess equivalence
1983 auto *InstMA = dyn_cast_or_null<MemoryDef>(MSSA->getMemoryAccess(I));
1984 bool InstWasMemoryLeader = InstMA && OldClass->getMemoryLeader() == InstMA;
1985 if (InstMA)
1986 moveMemoryToNewCongruenceClass(I, InstMA, OldClass, NewClass);
1987 ValueToClass[I] = NewClass;
1988 // See if we destroyed the class or need to swap leaders.
1989 if (OldClass->empty() && OldClass != TOPClass) {
1990 if (OldClass->getDefiningExpr()) {
1991 DEBUG(dbgs() << "Erasing expression " << OldClass->getDefiningExpr()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Erasing expression " << OldClass
->getDefiningExpr() << " from table\n"; } } while (false
)
1992 << " from table\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Erasing expression " << OldClass
->getDefiningExpr() << " from table\n"; } } while (false
)
;
1993 ExpressionToClass.erase(OldClass->getDefiningExpr());
1994 }
1995 } else if (OldClass->getLeader() == I) {
1996 // When the leader changes, the value numbering of
1997 // everything may change due to symbolization changes, so we need to
1998 // reprocess.
1999 DEBUG(dbgs() << "Value class leader change for class " << OldClass->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Value class leader change for class "
<< OldClass->getID() << "\n"; } } while (false
)
2000 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Value class leader change for class "
<< OldClass->getID() << "\n"; } } while (false
)
;
2001 ++NumGVNLeaderChanges;
2002 // Destroy the stored value if there are no more stores to represent it.
2003 // Note that this is basically clean up for the expression removal that
2004 // happens below. If we remove stores from a class, we may leave it as a
2005 // class of equivalent memory phis.
2006 if (OldClass->getStoreCount() == 0) {
2007 if (OldClass->getStoredValue())
2008 OldClass->setStoredValue(nullptr);
2009 }
2010 // If we destroy the old access leader and it's a store, we have to
2011 // effectively destroy the congruence class. When it comes to scalars,
2012 // anything with the same value is as good as any other. That means that
2013 // one leader is as good as another, and as long as you have some leader for
2014 // the value, you are good.. When it comes to *memory states*, only one
2015 // particular thing really represents the definition of a given memory
2016 // state. Once it goes away, we need to re-evaluate which pieces of memory
2017 // are really still equivalent. The best way to do this is to re-value
2018 // number things. The only way to really make that happen is to destroy the
2019 // rest of the class. In order to effectively destroy the class, we reset
2020 // ExpressionToClass for each by using the ValueToExpression mapping. The
2021 // members later get marked as touched due to the leader change. We will
2022 // create new congruence classes, and the pieces that are still equivalent
2023 // will end back together in a new class. If this becomes too expensive, it
2024 // is possible to use a versioning scheme for the congruence classes to
2025 // avoid the expressions finding this old class. Note that the situation is
2026 // different for memory phis, becuase they are evaluated anew each time, and
2027 // they become equal not by hashing, but by seeing if all operands are the
2028 // same (or only one is reachable).
2029 if (OldClass->getStoreCount() > 0 && InstWasMemoryLeader) {
2030 DEBUG(dbgs() << "Kicking everything out of class " << OldClass->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Kicking everything out of class "
<< OldClass->getID() << " because MemoryAccess leader changed"
; } } while (false)
2031 << " because MemoryAccess leader changed")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Kicking everything out of class "
<< OldClass->getID() << " because MemoryAccess leader changed"
; } } while (false)
;
2032 for (auto Member : *OldClass)
2033 ExpressionToClass.erase(ValueToExpression.lookup(Member));
2034 }
2035 OldClass->setLeader(getNextValueLeader(OldClass));
2036 OldClass->resetNextLeader();
2037 markValueLeaderChangeTouched(OldClass);
2038 }
2039}
2040
2041// Perform congruence finding on a given value numbering expression.
2042void NewGVN::performCongruenceFinding(Instruction *I, const Expression *E) {
2043 ValueToExpression[I] = E;
2044 // This is guaranteed to return something, since it will at least find
2045 // TOP.
2046
2047 CongruenceClass *IClass = ValueToClass[I];
2048 assert(IClass && "Should have found a IClass")((IClass && "Should have found a IClass") ? static_cast
<void> (0) : __assert_fail ("IClass && \"Should have found a IClass\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2048, __PRETTY_FUNCTION__))
;
2049 // Dead classes should have been eliminated from the mapping.
2050 assert(!IClass->isDead() && "Found a dead class")((!IClass->isDead() && "Found a dead class") ? static_cast
<void> (0) : __assert_fail ("!IClass->isDead() && \"Found a dead class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2050, __PRETTY_FUNCTION__))
;
2051
2052 CongruenceClass *EClass;
2053 if (const auto *VE = dyn_cast<VariableExpression>(E)) {
2054 EClass = ValueToClass[VE->getVariableValue()];
2055 } else {
2056 auto lookupResult = ExpressionToClass.insert({E, nullptr});
2057
2058 // If it's not in the value table, create a new congruence class.
2059 if (lookupResult.second) {
2060 CongruenceClass *NewClass = createCongruenceClass(nullptr, E);
2061 auto place = lookupResult.first;
2062 place->second = NewClass;
2063
2064 // Constants and variables should always be made the leader.
2065 if (const auto *CE = dyn_cast<ConstantExpression>(E)) {
2066 NewClass->setLeader(CE->getConstantValue());
2067 } else if (const auto *SE = dyn_cast<StoreExpression>(E)) {
2068 StoreInst *SI = SE->getStoreInst();
2069 NewClass->setLeader(SI);
2070 NewClass->setStoredValue(lookupOperandLeader(SI->getValueOperand()));
2071 // The RepMemoryAccess field will be filled in properly by the
2072 // moveValueToNewCongruenceClass call.
2073 } else {
2074 NewClass->setLeader(I);
2075 }
2076 assert(!isa<VariableExpression>(E) &&((!isa<VariableExpression>(E) && "VariableExpression should have been handled already"
) ? static_cast<void> (0) : __assert_fail ("!isa<VariableExpression>(E) && \"VariableExpression should have been handled already\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2077, __PRETTY_FUNCTION__))
2077 "VariableExpression should have been handled already")((!isa<VariableExpression>(E) && "VariableExpression should have been handled already"
) ? static_cast<void> (0) : __assert_fail ("!isa<VariableExpression>(E) && \"VariableExpression should have been handled already\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2077, __PRETTY_FUNCTION__))
;
2078
2079 EClass = NewClass;
2080 DEBUG(dbgs() << "Created new congruence class for " << *Ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Created new congruence class for "
<< *I << " using expression " << *E <<
" at " << NewClass->getID() << " and leader "
<< *(NewClass->getLeader()); } } while (false)
2081 << " using expression " << *E << " at " << NewClass->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Created new congruence class for "
<< *I << " using expression " << *E <<
" at " << NewClass->getID() << " and leader "
<< *(NewClass->getLeader()); } } while (false)
2082 << " and leader " << *(NewClass->getLeader()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Created new congruence class for "
<< *I << " using expression " << *E <<
" at " << NewClass->getID() << " and leader "
<< *(NewClass->getLeader()); } } while (false)
;
2083 if (NewClass->getStoredValue())
2084 DEBUG(dbgs() << " and stored value " << *(NewClass->getStoredValue()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " and stored value " << *
(NewClass->getStoredValue()); } } while (false)
;
2085 DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "\n"; } } while (false)
;
2086 } else {
2087 EClass = lookupResult.first->second;
2088 if (isa<ConstantExpression>(E))
2089 assert((isa<Constant>(EClass->getLeader()) ||(((isa<Constant>(EClass->getLeader()) || (EClass->
getStoredValue() && isa<Constant>(EClass->getStoredValue
()))) && "Any class with a constant expression should have a "
"constant leader") ? static_cast<void> (0) : __assert_fail
("(isa<Constant>(EClass->getLeader()) || (EClass->getStoredValue() && isa<Constant>(EClass->getStoredValue()))) && \"Any class with a constant expression should have a \" \"constant leader\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2093, __PRETTY_FUNCTION__))
2090 (EClass->getStoredValue() &&(((isa<Constant>(EClass->getLeader()) || (EClass->
getStoredValue() && isa<Constant>(EClass->getStoredValue
()))) && "Any class with a constant expression should have a "
"constant leader") ? static_cast<void> (0) : __assert_fail
("(isa<Constant>(EClass->getLeader()) || (EClass->getStoredValue() && isa<Constant>(EClass->getStoredValue()))) && \"Any class with a constant expression should have a \" \"constant leader\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2093, __PRETTY_FUNCTION__))
2091 isa<Constant>(EClass->getStoredValue()))) &&(((isa<Constant>(EClass->getLeader()) || (EClass->
getStoredValue() && isa<Constant>(EClass->getStoredValue
()))) && "Any class with a constant expression should have a "
"constant leader") ? static_cast<void> (0) : __assert_fail
("(isa<Constant>(EClass->getLeader()) || (EClass->getStoredValue() && isa<Constant>(EClass->getStoredValue()))) && \"Any class with a constant expression should have a \" \"constant leader\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2093, __PRETTY_FUNCTION__))
2092 "Any class with a constant expression should have a "(((isa<Constant>(EClass->getLeader()) || (EClass->
getStoredValue() && isa<Constant>(EClass->getStoredValue
()))) && "Any class with a constant expression should have a "
"constant leader") ? static_cast<void> (0) : __assert_fail
("(isa<Constant>(EClass->getLeader()) || (EClass->getStoredValue() && isa<Constant>(EClass->getStoredValue()))) && \"Any class with a constant expression should have a \" \"constant leader\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2093, __PRETTY_FUNCTION__))
2093 "constant leader")(((isa<Constant>(EClass->getLeader()) || (EClass->
getStoredValue() && isa<Constant>(EClass->getStoredValue
()))) && "Any class with a constant expression should have a "
"constant leader") ? static_cast<void> (0) : __assert_fail
("(isa<Constant>(EClass->getLeader()) || (EClass->getStoredValue() && isa<Constant>(EClass->getStoredValue()))) && \"Any class with a constant expression should have a \" \"constant leader\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2093, __PRETTY_FUNCTION__))
;
2094
2095 assert(EClass && "Somehow don't have an eclass")((EClass && "Somehow don't have an eclass") ? static_cast
<void> (0) : __assert_fail ("EClass && \"Somehow don't have an eclass\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2095, __PRETTY_FUNCTION__))
;
2096
2097 assert(!EClass->isDead() && "We accidentally looked up a dead class")((!EClass->isDead() && "We accidentally looked up a dead class"
) ? static_cast<void> (0) : __assert_fail ("!EClass->isDead() && \"We accidentally looked up a dead class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2097, __PRETTY_FUNCTION__))
;
2098 }
2099 }
2100 bool ClassChanged = IClass != EClass;
2101 bool LeaderChanged = LeaderChanges.erase(I);
2102 if (ClassChanged || LeaderChanged) {
2103 DEBUG(dbgs() << "New class " << EClass->getID() << " for expression " << *Edo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "New class " << EClass->
getID() << " for expression " << *E << "\n"
; } } while (false)
2104 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "New class " << EClass->
getID() << " for expression " << *E << "\n"
; } } while (false)
;
2105 if (ClassChanged)
2106 moveValueToNewCongruenceClass(I, E, IClass, EClass);
2107 markUsersTouched(I);
2108 if (MemoryAccess *MA = MSSA->getMemoryAccess(I))
2109 markMemoryUsersTouched(MA);
2110 if (auto *CI = dyn_cast<CmpInst>(I))
2111 markPredicateUsersTouched(CI);
2112 }
2113}
2114
2115// Process the fact that Edge (from, to) is reachable, including marking
2116// any newly reachable blocks and instructions for processing.
2117void NewGVN::updateReachableEdge(BasicBlock *From, BasicBlock *To) {
2118 // Check if the Edge was reachable before.
2119 if (ReachableEdges.insert({From, To}).second) {
2120 // If this block wasn't reachable before, all instructions are touched.
2121 if (ReachableBlocks.insert(To).second) {
2122 DEBUG(dbgs() << "Block " << getBlockName(To) << " marked reachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " marked reachable\n"; } } while (false)
;
2123 const auto &InstRange = BlockInstRange.lookup(To);
2124 TouchedInstructions.set(InstRange.first, InstRange.second);
2125 } else {
2126 DEBUG(dbgs() << "Block " << getBlockName(To)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " was reachable, but new edge {" << getBlockName
(From) << "," << getBlockName(To) << "} to it found\n"
; } } while (false)
2127 << " was reachable, but new edge {" << getBlockName(From)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " was reachable, but new edge {" << getBlockName
(From) << "," << getBlockName(To) << "} to it found\n"
; } } while (false)
2128 << "," << getBlockName(To) << "} to it found\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " was reachable, but new edge {" << getBlockName
(From) << "," << getBlockName(To) << "} to it found\n"
; } } while (false)
;
2129
2130 // We've made an edge reachable to an existing block, which may
2131 // impact predicates. Otherwise, only mark the phi nodes as touched, as
2132 // they are the only thing that depend on new edges. Anything using their
2133 // values will get propagated to if necessary.
2134 if (MemoryAccess *MemPhi = MSSA->getMemoryAccess(To))
2135 TouchedInstructions.set(InstrToDFSNum(MemPhi));
2136
2137 auto BI = To->begin();
2138 while (isa<PHINode>(BI)) {
2139 TouchedInstructions.set(InstrToDFSNum(&*BI));
2140 ++BI;
2141 }
2142 }
2143 }
2144}
2145
2146// Given a predicate condition (from a switch, cmp, or whatever) and a block,
2147// see if we know some constant value for it already.
2148Value *NewGVN::findConditionEquivalence(Value *Cond) const {
2149 auto Result = lookupOperandLeader(Cond);
2150 if (isa<Constant>(Result))
2151 return Result;
2152 return nullptr;
2153}
2154
2155// Process the outgoing edges of a block for reachability.
2156void NewGVN::processOutgoingEdges(TerminatorInst *TI, BasicBlock *B) {
2157 // Evaluate reachability of terminator instruction.
2158 BranchInst *BR;
2159 if ((BR = dyn_cast<BranchInst>(TI)) && BR->isConditional()) {
2160 Value *Cond = BR->getCondition();
2161 Value *CondEvaluated = findConditionEquivalence(Cond);
2162 if (!CondEvaluated) {
2163 if (auto *I = dyn_cast<Instruction>(Cond)) {
2164 const Expression *E = createExpression(I);
2165 if (const auto *CE = dyn_cast<ConstantExpression>(E)) {
2166 CondEvaluated = CE->getConstantValue();
2167 }
2168 } else if (isa<ConstantInt>(Cond)) {
2169 CondEvaluated = Cond;
2170 }
2171 }
2172 ConstantInt *CI;
2173 BasicBlock *TrueSucc = BR->getSuccessor(0);
2174 BasicBlock *FalseSucc = BR->getSuccessor(1);
2175 if (CondEvaluated && (CI = dyn_cast<ConstantInt>(CondEvaluated))) {
2176 if (CI->isOne()) {
2177 DEBUG(dbgs() << "Condition for Terminator " << *TIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to true\n"; } } while (false)
2178 << " evaluated to true\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to true\n"; } } while (false)
;
2179 updateReachableEdge(B, TrueSucc);
2180 } else if (CI->isZero()) {
2181 DEBUG(dbgs() << "Condition for Terminator " << *TIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to false\n"; } } while (false)
2182 << " evaluated to false\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to false\n"; } } while (false)
;
2183 updateReachableEdge(B, FalseSucc);
2184 }
2185 } else {
2186 updateReachableEdge(B, TrueSucc);
2187 updateReachableEdge(B, FalseSucc);
2188 }
2189 } else if (auto *SI = dyn_cast<SwitchInst>(TI)) {
2190 // For switches, propagate the case values into the case
2191 // destinations.
2192
2193 // Remember how many outgoing edges there are to every successor.
2194 SmallDenseMap<BasicBlock *, unsigned, 16> SwitchEdges;
2195
2196 Value *SwitchCond = SI->getCondition();
2197 Value *CondEvaluated = findConditionEquivalence(SwitchCond);
2198 // See if we were able to turn this switch statement into a constant.
2199 if (CondEvaluated && isa<ConstantInt>(CondEvaluated)) {
2200 auto *CondVal = cast<ConstantInt>(CondEvaluated);
2201 // We should be able to get case value for this.
2202 auto Case = *SI->findCaseValue(CondVal);
2203 if (Case.getCaseSuccessor() == SI->getDefaultDest()) {
2204 // We proved the value is outside of the range of the case.
2205 // We can't do anything other than mark the default dest as reachable,
2206 // and go home.
2207 updateReachableEdge(B, SI->getDefaultDest());
2208 return;
2209 }
2210 // Now get where it goes and mark it reachable.
2211 BasicBlock *TargetBlock = Case.getCaseSuccessor();
2212 updateReachableEdge(B, TargetBlock);
2213 } else {
2214 for (unsigned i = 0, e = SI->getNumSuccessors(); i != e; ++i) {
2215 BasicBlock *TargetBlock = SI->getSuccessor(i);
2216 ++SwitchEdges[TargetBlock];
2217 updateReachableEdge(B, TargetBlock);
2218 }
2219 }
2220 } else {
2221 // Otherwise this is either unconditional, or a type we have no
2222 // idea about. Just mark successors as reachable.
2223 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
2224 BasicBlock *TargetBlock = TI->getSuccessor(i);
2225 updateReachableEdge(B, TargetBlock);
2226 }
2227
2228 // This also may be a memory defining terminator, in which case, set it
2229 // equivalent only to itself.
2230 //
2231 auto *MA = MSSA->getMemoryAccess(TI);
2232 if (MA && !isa<MemoryUse>(MA)) {
2233 auto *CC = ensureLeaderOfMemoryClass(MA);
2234 if (setMemoryClass(MA, CC))
2235 markMemoryUsersTouched(MA);
2236 }
2237 }
2238}
2239
2240// The algorithm initially places the values of the routine in the TOP
2241// congruence class. The leader of TOP is the undetermined value `undef`.
2242// When the algorithm has finished, values still in TOP are unreachable.
2243void NewGVN::initializeCongruenceClasses(Function &F) {
2244 NextCongruenceNum = 0;
2245
2246 // Note that even though we use the live on entry def as a representative
2247 // MemoryAccess, it is *not* the same as the actual live on entry def. We
2248 // have no real equivalemnt to undef for MemoryAccesses, and so we really
2249 // should be checking whether the MemoryAccess is top if we want to know if it
2250 // is equivalent to everything. Otherwise, what this really signifies is that
2251 // the access "it reaches all the way back to the beginning of the function"
2252
2253 // Initialize all other instructions to be in TOP class.
2254 TOPClass = createCongruenceClass(nullptr, nullptr);
2255 TOPClass->setMemoryLeader(MSSA->getLiveOnEntryDef());
2256 // The live on entry def gets put into it's own class
2257 MemoryAccessToClass[MSSA->getLiveOnEntryDef()] =
2258 createMemoryClass(MSSA->getLiveOnEntryDef());
2259
2260 for (auto DTN : nodes(DT)) {
2261 BasicBlock *BB = DTN->getBlock();
2262 // All MemoryAccesses are equivalent to live on entry to start. They must
2263 // be initialized to something so that initial changes are noticed. For
2264 // the maximal answer, we initialize them all to be the same as
2265 // liveOnEntry.
2266 auto *MemoryBlockDefs = MSSA->getBlockDefs(BB);
2267 if (MemoryBlockDefs)
2268 for (const auto &Def : *MemoryBlockDefs) {
2269 MemoryAccessToClass[&Def] = TOPClass;
2270 auto *MD = dyn_cast<MemoryDef>(&Def);
2271 // Insert the memory phis into the member list.
2272 if (!MD) {
2273 const MemoryPhi *MP = cast<MemoryPhi>(&Def);
2274 TOPClass->memory_insert(MP);
2275 MemoryPhiState.insert({MP, MPS_TOP});
2276 }
2277
2278 if (MD && isa<StoreInst>(MD->getMemoryInst()))
2279 TOPClass->incStoreCount();
2280 }
2281 for (auto &I : *BB) {
2282 // Don't insert void terminators into the class. We don't value number
2283 // them, and they just end up sitting in TOP.
2284 if (isa<TerminatorInst>(I) && I.getType()->isVoidTy())
2285 continue;
2286 TOPClass->insert(&I);
2287 ValueToClass[&I] = TOPClass;
2288 }
2289 }
2290
2291 // Initialize arguments to be in their own unique congruence classes
2292 for (auto &FA : F.args())
2293 createSingletonCongruenceClass(&FA);
2294}
2295
2296void NewGVN::cleanupTables() {
2297 for (unsigned i = 0, e = CongruenceClasses.size(); i != e; ++i) {
2298 DEBUG(dbgs() << "Congruence class " << CongruenceClasses[i]->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Congruence class " << CongruenceClasses
[i]->getID() << " has " << CongruenceClasses[i
]->size() << " members\n"; } } while (false)
2299 << " has " << CongruenceClasses[i]->size() << " members\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Congruence class " << CongruenceClasses
[i]->getID() << " has " << CongruenceClasses[i
]->size() << " members\n"; } } while (false)
;
2300 // Make sure we delete the congruence class (probably worth switching to
2301 // a unique_ptr at some point.
2302 delete CongruenceClasses[i];
2303 CongruenceClasses[i] = nullptr;
2304 }
2305
2306 ValueToClass.clear();
2307 ArgRecycler.clear(ExpressionAllocator);
2308 ExpressionAllocator.Reset();
2309 CongruenceClasses.clear();
2310 ExpressionToClass.clear();
2311 ValueToExpression.clear();
2312 ReachableBlocks.clear();
2313 ReachableEdges.clear();
2314#ifndef NDEBUG
2315 ProcessedCount.clear();
2316#endif
2317 InstrDFS.clear();
2318 InstructionsToErase.clear();
2319 DFSToInstr.clear();
2320 BlockInstRange.clear();
2321 TouchedInstructions.clear();
2322 MemoryAccessToClass.clear();
2323 PredicateToUsers.clear();
2324 MemoryToUsers.clear();
2325}
2326
2327std::pair<unsigned, unsigned> NewGVN::assignDFSNumbers(BasicBlock *B,
2328 unsigned Start) {
2329 unsigned End = Start;
2330 if (MemoryAccess *MemPhi = MSSA->getMemoryAccess(B)) {
2331 InstrDFS[MemPhi] = End++;
2332 DFSToInstr.emplace_back(MemPhi);
2333 }
2334
2335 for (auto &I : *B) {
2336 // There's no need to call isInstructionTriviallyDead more than once on
2337 // an instruction. Therefore, once we know that an instruction is dead
2338 // we change its DFS number so that it doesn't get value numbered.
2339 if (isInstructionTriviallyDead(&I, TLI)) {
2340 InstrDFS[&I] = 0;
2341 DEBUG(dbgs() << "Skipping trivially dead instruction " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping trivially dead instruction "
<< I << "\n"; } } while (false)
;
2342 markInstructionForDeletion(&I);
2343 continue;
2344 }
2345
2346 InstrDFS[&I] = End++;
2347 DFSToInstr.emplace_back(&I);
2348 }
2349
2350 // All of the range functions taken half-open ranges (open on the end side).
2351 // So we do not subtract one from count, because at this point it is one
2352 // greater than the last instruction.
2353 return std::make_pair(Start, End);
2354}
2355
2356void NewGVN::updateProcessedCount(Value *V) {
2357#ifndef NDEBUG
2358 if (ProcessedCount.count(V) == 0) {
2359 ProcessedCount.insert({V, 1});
2360 } else {
2361 ++ProcessedCount[V];
2362 assert(ProcessedCount[V] < 100 &&((ProcessedCount[V] < 100 && "Seem to have processed the same Value a lot"
) ? static_cast<void> (0) : __assert_fail ("ProcessedCount[V] < 100 && \"Seem to have processed the same Value a lot\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2363, __PRETTY_FUNCTION__))
2363 "Seem to have processed the same Value a lot")((ProcessedCount[V] < 100 && "Seem to have processed the same Value a lot"
) ? static_cast<void> (0) : __assert_fail ("ProcessedCount[V] < 100 && \"Seem to have processed the same Value a lot\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2363, __PRETTY_FUNCTION__))
;
2364 }
2365#endif
2366}
2367// Evaluate MemoryPhi nodes symbolically, just like PHI nodes
2368void NewGVN::valueNumberMemoryPhi(MemoryPhi *MP) {
2369 // If all the arguments are the same, the MemoryPhi has the same value as the
2370 // argument.
2371 // Filter out unreachable blocks and self phis from our operands.
2372 const BasicBlock *PHIBlock = MP->getBlock();
2373 auto Filtered = make_filter_range(MP->operands(), [&](const Use &U) {
2374 return lookupMemoryLeader(cast<MemoryAccess>(U)) != MP &&
2375 !isMemoryAccessTop(cast<MemoryAccess>(U)) &&
2376 ReachableEdges.count({MP->getIncomingBlock(U), PHIBlock});
2377 });
2378 // If all that is left is nothing, our memoryphi is undef. We keep it as
2379 // InitialClass. Note: The only case this should happen is if we have at
2380 // least one self-argument.
2381 if (Filtered.begin() == Filtered.end()) {
2382 if (setMemoryClass(MP, TOPClass))
2383 markMemoryUsersTouched(MP);
2384 return;
2385 }
2386
2387 // Transform the remaining operands into operand leaders.
2388 // FIXME: mapped_iterator should have a range version.
2389 auto LookupFunc = [&](const Use &U) {
2390 return lookupMemoryLeader(cast<MemoryAccess>(U));
2391 };
2392 auto MappedBegin = map_iterator(Filtered.begin(), LookupFunc);
2393 auto MappedEnd = map_iterator(Filtered.end(), LookupFunc);
2394
2395 // and now check if all the elements are equal.
2396 // Sadly, we can't use std::equals since these are random access iterators.
2397 const auto *AllSameValue = *MappedBegin;
2398 ++MappedBegin;
2399 bool AllEqual = std::all_of(
2400 MappedBegin, MappedEnd,
2401 [&AllSameValue](const MemoryAccess *V) { return V == AllSameValue; });
2402
2403 if (AllEqual)
2404 DEBUG(dbgs() << "Memory Phi value numbered to " << *AllSameValue << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory Phi value numbered to "
<< *AllSameValue << "\n"; } } while (false)
;
2405 else
2406 DEBUG(dbgs() << "Memory Phi value numbered to itself\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory Phi value numbered to itself\n"
; } } while (false)
;
2407 // If it's equal to something, it's in that class. Otherwise, it has to be in
2408 // a class where it is the leader (other things may be equivalent to it, but
2409 // it needs to start off in its own class, which means it must have been the
2410 // leader, and it can't have stopped being the leader because it was never
2411 // removed).
2412 CongruenceClass *CC =
2413 AllEqual ? getMemoryClass(AllSameValue) : ensureLeaderOfMemoryClass(MP);
2414 auto OldState = MemoryPhiState.lookup(MP);
2415 assert(OldState != MPS_Invalid && "Invalid memory phi state")((OldState != MPS_Invalid && "Invalid memory phi state"
) ? static_cast<void> (0) : __assert_fail ("OldState != MPS_Invalid && \"Invalid memory phi state\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2415, __PRETTY_FUNCTION__))
;
2416 auto NewState = AllEqual ? MPS_Equivalent : MPS_Unique;
2417 MemoryPhiState[MP] = NewState;
2418 if (setMemoryClass(MP, CC) || OldState != NewState)
2419 markMemoryUsersTouched(MP);
2420}
2421
2422// Value number a single instruction, symbolically evaluating, performing
2423// congruence finding, and updating mappings.
2424void NewGVN::valueNumberInstruction(Instruction *I) {
2425 DEBUG(dbgs() << "Processing instruction " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Processing instruction " <<
*I << "\n"; } } while (false)
;
2426 if (!I->isTerminator()) {
2427 const Expression *Symbolized = nullptr;
2428 if (DebugCounter::shouldExecute(VNCounter)) {
2429 Symbolized = performSymbolicEvaluation(I);
2430 } else {
2431 // Mark the instruction as unused so we don't value number it again.
2432 InstrDFS[I] = 0;
2433 }
2434 // If we couldn't come up with a symbolic expression, use the unknown
2435 // expression
2436 if (Symbolized == nullptr) {
2437 Symbolized = createUnknownExpression(I);
2438 }
2439
2440 performCongruenceFinding(I, Symbolized);
2441 } else {
2442 // Handle terminators that return values. All of them produce values we
2443 // don't currently understand. We don't place non-value producing
2444 // terminators in a class.
2445 if (!I->getType()->isVoidTy()) {
2446 auto *Symbolized = createUnknownExpression(I);
2447 performCongruenceFinding(I, Symbolized);
2448 }
2449 processOutgoingEdges(dyn_cast<TerminatorInst>(I), I->getParent());
2450 }
2451}
2452
2453// Check if there is a path, using single or equal argument phi nodes, from
2454// First to Second.
2455bool NewGVN::singleReachablePHIPath(const MemoryAccess *First,
2456 const MemoryAccess *Second) const {
2457 if (First == Second)
2458 return true;
2459 if (MSSA->isLiveOnEntryDef(First))
2460 return false;
2461
2462 const auto *EndDef = First;
2463 for (auto *ChainDef : optimized_def_chain(First)) {
2464 if (ChainDef == Second)
2465 return true;
2466 if (MSSA->isLiveOnEntryDef(ChainDef))
2467 return false;
2468 EndDef = ChainDef;
2469 }
2470 auto *MP = cast<MemoryPhi>(EndDef);
2471 auto ReachableOperandPred = [&](const Use &U) {
2472 return ReachableEdges.count({MP->getIncomingBlock(U), MP->getBlock()});
2473 };
2474 auto FilteredPhiArgs =
2475 make_filter_range(MP->operands(), ReachableOperandPred);
2476 SmallVector<const Value *, 32> OperandList;
2477 std::copy(FilteredPhiArgs.begin(), FilteredPhiArgs.end(),
2478 std::back_inserter(OperandList));
2479 bool Okay = OperandList.size() == 1;
2480 if (!Okay)
2481 Okay =
2482 std::equal(OperandList.begin(), OperandList.end(), OperandList.begin());
2483 if (Okay)
2484 return singleReachablePHIPath(cast<MemoryAccess>(OperandList[0]), Second);
2485 return false;
2486}
2487
2488// Verify the that the memory equivalence table makes sense relative to the
2489// congruence classes. Note that this checking is not perfect, and is currently
2490// subject to very rare false negatives. It is only useful for
2491// testing/debugging.
2492void NewGVN::verifyMemoryCongruency() const {
2493#ifndef NDEBUG
2494 // Verify that the memory table equivalence and memory member set match
2495 for (const auto *CC : CongruenceClasses) {
2496 if (CC == TOPClass || CC->isDead())
2497 continue;
2498 if (CC->getStoreCount() != 0) {
2499 assert((CC->getStoredValue() || !isa<StoreInst>(CC->getLeader())) &&(((CC->getStoredValue() || !isa<StoreInst>(CC->getLeader
())) && "Any class with a store as a " "leader should have a "
"representative stored value\n") ? static_cast<void> (
0) : __assert_fail ("(CC->getStoredValue() || !isa<StoreInst>(CC->getLeader())) && \"Any class with a store as a \" \"leader should have a \" \"representative stored value\\n\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2502, __PRETTY_FUNCTION__))
2500 "Any class with a store as a "(((CC->getStoredValue() || !isa<StoreInst>(CC->getLeader
())) && "Any class with a store as a " "leader should have a "
"representative stored value\n") ? static_cast<void> (
0) : __assert_fail ("(CC->getStoredValue() || !isa<StoreInst>(CC->getLeader())) && \"Any class with a store as a \" \"leader should have a \" \"representative stored value\\n\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2502, __PRETTY_FUNCTION__))
2501 "leader should have a "(((CC->getStoredValue() || !isa<StoreInst>(CC->getLeader
())) && "Any class with a store as a " "leader should have a "
"representative stored value\n") ? static_cast<void> (
0) : __assert_fail ("(CC->getStoredValue() || !isa<StoreInst>(CC->getLeader())) && \"Any class with a store as a \" \"leader should have a \" \"representative stored value\\n\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2502, __PRETTY_FUNCTION__))
2502 "representative stored value\n")(((CC->getStoredValue() || !isa<StoreInst>(CC->getLeader
())) && "Any class with a store as a " "leader should have a "
"representative stored value\n") ? static_cast<void> (
0) : __assert_fail ("(CC->getStoredValue() || !isa<StoreInst>(CC->getLeader())) && \"Any class with a store as a \" \"leader should have a \" \"representative stored value\\n\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2502, __PRETTY_FUNCTION__))
;
2503 assert(CC->getMemoryLeader() &&((CC->getMemoryLeader() && "Any congruence class with a store should "
"have a representative access\n") ? static_cast<void> (
0) : __assert_fail ("CC->getMemoryLeader() && \"Any congruence class with a store should \" \"have a representative access\\n\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2505, __PRETTY_FUNCTION__))
2504 "Any congruence class with a store should "((CC->getMemoryLeader() && "Any congruence class with a store should "
"have a representative access\n") ? static_cast<void> (
0) : __assert_fail ("CC->getMemoryLeader() && \"Any congruence class with a store should \" \"have a representative access\\n\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2505, __PRETTY_FUNCTION__))
2505 "have a representative access\n")((CC->getMemoryLeader() && "Any congruence class with a store should "
"have a representative access\n") ? static_cast<void> (
0) : __assert_fail ("CC->getMemoryLeader() && \"Any congruence class with a store should \" \"have a representative access\\n\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2505, __PRETTY_FUNCTION__))
;
2506 }
2507
2508 if (CC->getMemoryLeader())
2509 assert(MemoryAccessToClass.lookup(CC->getMemoryLeader()) == CC &&((MemoryAccessToClass.lookup(CC->getMemoryLeader()) == CC &&
"Representative MemoryAccess does not appear to be reverse "
"mapped properly") ? static_cast<void> (0) : __assert_fail
("MemoryAccessToClass.lookup(CC->getMemoryLeader()) == CC && \"Representative MemoryAccess does not appear to be reverse \" \"mapped properly\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2511, __PRETTY_FUNCTION__))
2510 "Representative MemoryAccess does not appear to be reverse "((MemoryAccessToClass.lookup(CC->getMemoryLeader()) == CC &&
"Representative MemoryAccess does not appear to be reverse "
"mapped properly") ? static_cast<void> (0) : __assert_fail
("MemoryAccessToClass.lookup(CC->getMemoryLeader()) == CC && \"Representative MemoryAccess does not appear to be reverse \" \"mapped properly\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2511, __PRETTY_FUNCTION__))
2511 "mapped properly")((MemoryAccessToClass.lookup(CC->getMemoryLeader()) == CC &&
"Representative MemoryAccess does not appear to be reverse "
"mapped properly") ? static_cast<void> (0) : __assert_fail
("MemoryAccessToClass.lookup(CC->getMemoryLeader()) == CC && \"Representative MemoryAccess does not appear to be reverse \" \"mapped properly\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2511, __PRETTY_FUNCTION__))
;
2512 for (auto M : CC->memory())
2513 assert(MemoryAccessToClass.lookup(M) == CC &&((MemoryAccessToClass.lookup(M) == CC && "Memory member does not appear to be reverse mapped properly"
) ? static_cast<void> (0) : __assert_fail ("MemoryAccessToClass.lookup(M) == CC && \"Memory member does not appear to be reverse mapped properly\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2514, __PRETTY_FUNCTION__))
2514 "Memory member does not appear to be reverse mapped properly")((MemoryAccessToClass.lookup(M) == CC && "Memory member does not appear to be reverse mapped properly"
) ? static_cast<void> (0) : __assert_fail ("MemoryAccessToClass.lookup(M) == CC && \"Memory member does not appear to be reverse mapped properly\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2514, __PRETTY_FUNCTION__))
;
2515 }
2516
2517 // Anything equivalent in the MemoryAccess table should be in the same
2518 // congruence class.
2519
2520 // Filter out the unreachable and trivially dead entries, because they may
2521 // never have been updated if the instructions were not processed.
2522 auto ReachableAccessPred =
2523 [&](const std::pair<const MemoryAccess *, CongruenceClass *> Pair) {
2524 bool Result = ReachableBlocks.count(Pair.first->getBlock());
2525 if (!Result || MSSA->isLiveOnEntryDef(Pair.first) ||
2526 MemoryToDFSNum(Pair.first) == 0)
2527 return false;
2528 if (auto *MemDef = dyn_cast<MemoryDef>(Pair.first))
2529 return !isInstructionTriviallyDead(MemDef->getMemoryInst());
2530 return true;
2531 };
2532
2533 auto Filtered = make_filter_range(MemoryAccessToClass, ReachableAccessPred);
2534 for (auto KV : Filtered) {
2535 assert(KV.second != TOPClass &&((KV.second != TOPClass && "Memory not unreachable but ended up in TOP"
) ? static_cast<void> (0) : __assert_fail ("KV.second != TOPClass && \"Memory not unreachable but ended up in TOP\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2536, __PRETTY_FUNCTION__))
2536 "Memory not unreachable but ended up in TOP")((KV.second != TOPClass && "Memory not unreachable but ended up in TOP"
) ? static_cast<void> (0) : __assert_fail ("KV.second != TOPClass && \"Memory not unreachable but ended up in TOP\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2536, __PRETTY_FUNCTION__))
;
2537 if (auto *FirstMUD = dyn_cast<MemoryUseOrDef>(KV.first)) {
2538 auto *SecondMUD = dyn_cast<MemoryUseOrDef>(KV.second->getMemoryLeader());
2539 if (FirstMUD && SecondMUD)
2540 assert((singleReachablePHIPath(FirstMUD, SecondMUD) ||(((singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass
.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(
SecondMUD->getMemoryInst())) && "The instructions for these memory operations should have "
"been in the same congruence class or reachable through" "a single argument phi"
) ? static_cast<void> (0) : __assert_fail ("(singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(SecondMUD->getMemoryInst())) && \"The instructions for these memory operations should have \" \"been in the same congruence class or reachable through\" \"a single argument phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2545, __PRETTY_FUNCTION__))
2541 ValueToClass.lookup(FirstMUD->getMemoryInst()) ==(((singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass
.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(
SecondMUD->getMemoryInst())) && "The instructions for these memory operations should have "
"been in the same congruence class or reachable through" "a single argument phi"
) ? static_cast<void> (0) : __assert_fail ("(singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(SecondMUD->getMemoryInst())) && \"The instructions for these memory operations should have \" \"been in the same congruence class or reachable through\" \"a single argument phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2545, __PRETTY_FUNCTION__))
2542 ValueToClass.lookup(SecondMUD->getMemoryInst())) &&(((singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass
.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(
SecondMUD->getMemoryInst())) && "The instructions for these memory operations should have "
"been in the same congruence class or reachable through" "a single argument phi"
) ? static_cast<void> (0) : __assert_fail ("(singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(SecondMUD->getMemoryInst())) && \"The instructions for these memory operations should have \" \"been in the same congruence class or reachable through\" \"a single argument phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2545, __PRETTY_FUNCTION__))
2543 "The instructions for these memory operations should have "(((singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass
.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(
SecondMUD->getMemoryInst())) && "The instructions for these memory operations should have "
"been in the same congruence class or reachable through" "a single argument phi"
) ? static_cast<void> (0) : __assert_fail ("(singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(SecondMUD->getMemoryInst())) && \"The instructions for these memory operations should have \" \"been in the same congruence class or reachable through\" \"a single argument phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2545, __PRETTY_FUNCTION__))
2544 "been in the same congruence class or reachable through"(((singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass
.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(
SecondMUD->getMemoryInst())) && "The instructions for these memory operations should have "
"been in the same congruence class or reachable through" "a single argument phi"
) ? static_cast<void> (0) : __assert_fail ("(singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(SecondMUD->getMemoryInst())) && \"The instructions for these memory operations should have \" \"been in the same congruence class or reachable through\" \"a single argument phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2545, __PRETTY_FUNCTION__))
2545 "a single argument phi")(((singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass
.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(
SecondMUD->getMemoryInst())) && "The instructions for these memory operations should have "
"been in the same congruence class or reachable through" "a single argument phi"
) ? static_cast<void> (0) : __assert_fail ("(singleReachablePHIPath(FirstMUD, SecondMUD) || ValueToClass.lookup(FirstMUD->getMemoryInst()) == ValueToClass.lookup(SecondMUD->getMemoryInst())) && \"The instructions for these memory operations should have \" \"been in the same congruence class or reachable through\" \"a single argument phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2545, __PRETTY_FUNCTION__))
;
2546 } else if (auto *FirstMP = dyn_cast<MemoryPhi>(KV.first)) {
2547 // We can only sanely verify that MemoryDefs in the operand list all have
2548 // the same class.
2549 auto ReachableOperandPred = [&](const Use &U) {
2550 return ReachableEdges.count(
2551 {FirstMP->getIncomingBlock(U), FirstMP->getBlock()}) &&
2552 isa<MemoryDef>(U);
2553
2554 };
2555 // All arguments should in the same class, ignoring unreachable arguments
2556 auto FilteredPhiArgs =
2557 make_filter_range(FirstMP->operands(), ReachableOperandPred);
2558 SmallVector<const CongruenceClass *, 16> PhiOpClasses;
2559 std::transform(FilteredPhiArgs.begin(), FilteredPhiArgs.end(),
2560 std::back_inserter(PhiOpClasses), [&](const Use &U) {
2561 const MemoryDef *MD = cast<MemoryDef>(U);
2562 return ValueToClass.lookup(MD->getMemoryInst());
2563 });
2564 assert(std::equal(PhiOpClasses.begin(), PhiOpClasses.end(),((std::equal(PhiOpClasses.begin(), PhiOpClasses.end(), PhiOpClasses
.begin()) && "All MemoryPhi arguments should be in the same class"
) ? static_cast<void> (0) : __assert_fail ("std::equal(PhiOpClasses.begin(), PhiOpClasses.end(), PhiOpClasses.begin()) && \"All MemoryPhi arguments should be in the same class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2566, __PRETTY_FUNCTION__))
2565 PhiOpClasses.begin()) &&((std::equal(PhiOpClasses.begin(), PhiOpClasses.end(), PhiOpClasses
.begin()) && "All MemoryPhi arguments should be in the same class"
) ? static_cast<void> (0) : __assert_fail ("std::equal(PhiOpClasses.begin(), PhiOpClasses.end(), PhiOpClasses.begin()) && \"All MemoryPhi arguments should be in the same class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2566, __PRETTY_FUNCTION__))
2566 "All MemoryPhi arguments should be in the same class")((std::equal(PhiOpClasses.begin(), PhiOpClasses.end(), PhiOpClasses
.begin()) && "All MemoryPhi arguments should be in the same class"
) ? static_cast<void> (0) : __assert_fail ("std::equal(PhiOpClasses.begin(), PhiOpClasses.end(), PhiOpClasses.begin()) && \"All MemoryPhi arguments should be in the same class\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2566, __PRETTY_FUNCTION__))
;
2567 }
2568 }
2569#endif
2570}
2571
2572// Verify that the sparse propagation we did actually found the maximal fixpoint
2573// We do this by storing the value to class mapping, touching all instructions,
2574// and redoing the iteration to see if anything changed.
2575void NewGVN::verifyIterationSettled(Function &F) {
2576#ifndef NDEBUG
2577 DEBUG(dbgs() << "Beginning iteration verification\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Beginning iteration verification\n"
; } } while (false)
;
2578 if (DebugCounter::isCounterSet(VNCounter))
2579 DebugCounter::setCounterValue(VNCounter, StartingVNCounter);
2580
2581 // Note that we have to store the actual classes, as we may change existing
2582 // classes during iteration. This is because our memory iteration propagation
2583 // is not perfect, and so may waste a little work. But it should generate
2584 // exactly the same congruence classes we have now, with different IDs.
2585 std::map<const Value *, CongruenceClass> BeforeIteration;
2586
2587 for (auto &KV : ValueToClass) {
2588 if (auto *I = dyn_cast<Instruction>(KV.first))
2589 // Skip unused/dead instructions.
2590 if (InstrToDFSNum(I) == 0)
2591 continue;
2592 BeforeIteration.insert({KV.first, *KV.second});
2593 }
2594
2595 TouchedInstructions.set();
2596 TouchedInstructions.reset(0);
2597 iterateTouchedInstructions();
2598 DenseSet<std::pair<const CongruenceClass *, const CongruenceClass *>>
2599 EqualClasses;
2600 for (const auto &KV : ValueToClass) {
2601 if (auto *I = dyn_cast<Instruction>(KV.first))
2602 // Skip unused/dead instructions.
2603 if (InstrToDFSNum(I) == 0)
2604 continue;
2605 // We could sink these uses, but i think this adds a bit of clarity here as
2606 // to what we are comparing.
2607 auto *BeforeCC = &BeforeIteration.find(KV.first)->second;
2608 auto *AfterCC = KV.second;
2609 // Note that the classes can't change at this point, so we memoize the set
2610 // that are equal.
2611 if (!EqualClasses.count({BeforeCC, AfterCC})) {
2612 assert(BeforeCC->isEquivalentTo(AfterCC) &&((BeforeCC->isEquivalentTo(AfterCC) && "Value number changed after main loop completed!"
) ? static_cast<void> (0) : __assert_fail ("BeforeCC->isEquivalentTo(AfterCC) && \"Value number changed after main loop completed!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2613, __PRETTY_FUNCTION__))
2613 "Value number changed after main loop completed!")((BeforeCC->isEquivalentTo(AfterCC) && "Value number changed after main loop completed!"
) ? static_cast<void> (0) : __assert_fail ("BeforeCC->isEquivalentTo(AfterCC) && \"Value number changed after main loop completed!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2613, __PRETTY_FUNCTION__))
;
2614 EqualClasses.insert({BeforeCC, AfterCC});
2615 }
2616 }
2617#endif
2618}
2619
2620// This is the main value numbering loop, it iterates over the initial touched
2621// instruction set, propagating value numbers, marking things touched, etc,
2622// until the set of touched instructions is completely empty.
2623void NewGVN::iterateTouchedInstructions() {
2624 unsigned int Iterations = 0;
2625 // Figure out where touchedinstructions starts
2626 int FirstInstr = TouchedInstructions.find_first();
2627 // Nothing set, nothing to iterate, just return.
2628 if (FirstInstr == -1)
2629 return;
2630 BasicBlock *LastBlock = getBlockForValue(InstrFromDFSNum(FirstInstr));
2631 while (TouchedInstructions.any()) {
2632 ++Iterations;
2633 // Walk through all the instructions in all the blocks in RPO.
2634 // TODO: As we hit a new block, we should push and pop equalities into a
2635 // table lookupOperandLeader can use, to catch things PredicateInfo
2636 // might miss, like edge-only equivalences.
2637 for (int InstrNum = TouchedInstructions.find_first(); InstrNum != -1;
2638 InstrNum = TouchedInstructions.find_next(InstrNum)) {
2639
2640 // This instruction was found to be dead. We don't bother looking
2641 // at it again.
2642 if (InstrNum == 0) {
2643 TouchedInstructions.reset(InstrNum);
2644 continue;
2645 }
2646
2647 Value *V = InstrFromDFSNum(InstrNum);
2648 BasicBlock *CurrBlock = getBlockForValue(V);
2649
2650 // If we hit a new block, do reachability processing.
2651 if (CurrBlock != LastBlock) {
2652 LastBlock = CurrBlock;
2653 bool BlockReachable = ReachableBlocks.count(CurrBlock);
2654 const auto &CurrInstRange = BlockInstRange.lookup(CurrBlock);
2655
2656 // If it's not reachable, erase any touched instructions and move on.
2657 if (!BlockReachable) {
2658 TouchedInstructions.reset(CurrInstRange.first, CurrInstRange.second);
2659 DEBUG(dbgs() << "Skipping instructions in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping instructions in block "
<< getBlockName(CurrBlock) << " because it is unreachable\n"
; } } while (false)
2660 << getBlockName(CurrBlock)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping instructions in block "
<< getBlockName(CurrBlock) << " because it is unreachable\n"
; } } while (false)
2661 << " because it is unreachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping instructions in block "
<< getBlockName(CurrBlock) << " because it is unreachable\n"
; } } while (false)
;
2662 continue;
2663 }
2664 updateProcessedCount(CurrBlock);
2665 }
2666
2667 if (auto *MP = dyn_cast<MemoryPhi>(V)) {
2668 DEBUG(dbgs() << "Processing MemoryPhi " << *MP << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Processing MemoryPhi " <<
*MP << "\n"; } } while (false)
;
2669 valueNumberMemoryPhi(MP);
2670 } else if (auto *I = dyn_cast<Instruction>(V)) {
2671 valueNumberInstruction(I);
2672 } else {
2673 llvm_unreachable("Should have been a MemoryPhi or Instruction")::llvm::llvm_unreachable_internal("Should have been a MemoryPhi or Instruction"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2673)
;
2674 }
2675 updateProcessedCount(V);
2676 // Reset after processing (because we may mark ourselves as touched when
2677 // we propagate equalities).
2678 TouchedInstructions.reset(InstrNum);
2679 }
2680 }
2681 NumGVNMaxIterations = std::max(NumGVNMaxIterations.getValue(), Iterations);
2682}
2683
2684// This is the main transformation entry point.
2685bool NewGVN::runGVN() {
2686 if (DebugCounter::isCounterSet(VNCounter))
2687 StartingVNCounter = DebugCounter::getCounterValue(VNCounter);
2688 bool Changed = false;
2689 NumFuncArgs = F.arg_size();
2690 MSSAWalker = MSSA->getWalker();
2691
2692 // Count number of instructions for sizing of hash tables, and come
2693 // up with a global dfs numbering for instructions.
2694 unsigned ICount = 1;
2695 // Add an empty instruction to account for the fact that we start at 1
2696 DFSToInstr.emplace_back(nullptr);
2697 // Note: We want ideal RPO traversal of the blocks, which is not quite the
2698 // same as dominator tree order, particularly with regard whether backedges
2699 // get visited first or second, given a block with multiple successors.
2700 // If we visit in the wrong order, we will end up performing N times as many
2701 // iterations.
2702 // The dominator tree does guarantee that, for a given dom tree node, it's
2703 // parent must occur before it in the RPO ordering. Thus, we only need to sort
2704 // the siblings.
2705 ReversePostOrderTraversal<Function *> RPOT(&F);
2706 unsigned Counter = 0;
2707 for (auto &B : RPOT) {
2708 auto *Node = DT->getNode(B);
2709 assert(Node && "RPO and Dominator tree should have same reachability")((Node && "RPO and Dominator tree should have same reachability"
) ? static_cast<void> (0) : __assert_fail ("Node && \"RPO and Dominator tree should have same reachability\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2709, __PRETTY_FUNCTION__))
;
2710 RPOOrdering[Node] = ++Counter;
2711 }
2712 // Sort dominator tree children arrays into RPO.
2713 for (auto &B : RPOT) {
2714 auto *Node = DT->getNode(B);
2715 if (Node->getChildren().size() > 1)
2716 std::sort(Node->begin(), Node->end(),
2717 [&](const DomTreeNode *A, const DomTreeNode *B) {
2718 return RPOOrdering[A] < RPOOrdering[B];
2719 });
2720 }
2721
2722 // Now a standard depth first ordering of the domtree is equivalent to RPO.
2723 for (auto DTN : depth_first(DT->getRootNode())) {
2724 BasicBlock *B = DTN->getBlock();
2725 const auto &BlockRange = assignDFSNumbers(B, ICount);
2726 BlockInstRange.insert({B, BlockRange});
2727 ICount += BlockRange.second - BlockRange.first;
2728 }
2729
2730 TouchedInstructions.resize(ICount);
2731 // Ensure we don't end up resizing the expressionToClass map, as
2732 // that can be quite expensive. At most, we have one expression per
2733 // instruction.
2734 ExpressionToClass.reserve(ICount);
2735
2736 // Initialize the touched instructions to include the entry block.
2737 const auto &InstRange = BlockInstRange.lookup(&F.getEntryBlock());
2738 TouchedInstructions.set(InstRange.first, InstRange.second);
2739 ReachableBlocks.insert(&F.getEntryBlock());
2740
2741 initializeCongruenceClasses(F);
2742 iterateTouchedInstructions();
2743 verifyMemoryCongruency();
2744 verifyIterationSettled(F);
2745
2746 Changed |= eliminateInstructions(F);
2747
2748 // Delete all instructions marked for deletion.
2749 for (Instruction *ToErase : InstructionsToErase) {
2750 if (!ToErase->use_empty())
2751 ToErase->replaceAllUsesWith(UndefValue::get(ToErase->getType()));
2752
2753 ToErase->eraseFromParent();
2754 }
2755
2756 // Delete all unreachable blocks.
2757 auto UnreachableBlockPred = [&](const BasicBlock &BB) {
2758 return !ReachableBlocks.count(&BB);
2759 };
2760
2761 for (auto &BB : make_filter_range(F, UnreachableBlockPred)) {
2762 DEBUG(dbgs() << "We believe block " << getBlockName(&BB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "We believe block " << getBlockName
(&BB) << " is unreachable\n"; } } while (false)
2763 << " is unreachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "We believe block " << getBlockName
(&BB) << " is unreachable\n"; } } while (false)
;
2764 deleteInstructionsInBlock(&BB);
2765 Changed = true;
2766 }
2767
2768 cleanupTables();
2769 return Changed;
2770}
2771
2772// Return true if V is a value that will always be available (IE can
2773// be placed anywhere) in the function. We don't do globals here
2774// because they are often worse to put in place.
2775// TODO: Separate cost from availability
2776static bool alwaysAvailable(Value *V) {
2777 return isa<Constant>(V) || isa<Argument>(V);
2778}
2779
2780struct NewGVN::ValueDFS {
2781 int DFSIn = 0;
2782 int DFSOut = 0;
2783 int LocalNum = 0;
2784 // Only one of Def and U will be set.
2785 // The bool in the Def tells us whether the Def is the stored value of a
2786 // store.
2787 PointerIntPair<Value *, 1, bool> Def;
2788 Use *U = nullptr;
2789 bool operator<(const ValueDFS &Other) const {
2790 // It's not enough that any given field be less than - we have sets
2791 // of fields that need to be evaluated together to give a proper ordering.
2792 // For example, if you have;
2793 // DFS (1, 3)
2794 // Val 0
2795 // DFS (1, 2)
2796 // Val 50
2797 // We want the second to be less than the first, but if we just go field
2798 // by field, we will get to Val 0 < Val 50 and say the first is less than
2799 // the second. We only want it to be less than if the DFS orders are equal.
2800 //
2801 // Each LLVM instruction only produces one value, and thus the lowest-level
2802 // differentiator that really matters for the stack (and what we use as as a
2803 // replacement) is the local dfs number.
2804 // Everything else in the structure is instruction level, and only affects
2805 // the order in which we will replace operands of a given instruction.
2806 //
2807 // For a given instruction (IE things with equal dfsin, dfsout, localnum),
2808 // the order of replacement of uses does not matter.
2809 // IE given,
2810 // a = 5
2811 // b = a + a
2812 // When you hit b, you will have two valuedfs with the same dfsin, out, and
2813 // localnum.
2814 // The .val will be the same as well.
2815 // The .u's will be different.
2816 // You will replace both, and it does not matter what order you replace them
2817 // in (IE whether you replace operand 2, then operand 1, or operand 1, then
2818 // operand 2).
2819 // Similarly for the case of same dfsin, dfsout, localnum, but different
2820 // .val's
2821 // a = 5
2822 // b = 6
2823 // c = a + b
2824 // in c, we will a valuedfs for a, and one for b,with everything the same
2825 // but .val and .u.
2826 // It does not matter what order we replace these operands in.
2827 // You will always end up with the same IR, and this is guaranteed.
2828 return std::tie(DFSIn, DFSOut, LocalNum, Def, U) <
2829 std::tie(Other.DFSIn, Other.DFSOut, Other.LocalNum, Other.Def,
2830 Other.U);
2831 }
2832};
2833
2834// This function converts the set of members for a congruence class from values,
2835// to sets of defs and uses with associated DFS info. The total number of
2836// reachable uses for each value is stored in UseCount, and instructions that
2837// seem
2838// dead (have no non-dead uses) are stored in ProbablyDead.
2839void NewGVN::convertClassToDFSOrdered(
2840 const CongruenceClass &Dense, SmallVectorImpl<ValueDFS> &DFSOrderedSet,
2841 DenseMap<const Value *, unsigned int> &UseCounts,
2842 SmallPtrSetImpl<Instruction *> &ProbablyDead) const {
2843 for (auto D : Dense) {
2844 // First add the value.
2845 BasicBlock *BB = getBlockForValue(D);
2846 // Constants are handled prior to ever calling this function, so
2847 // we should only be left with instructions as members.
2848 assert(BB && "Should have figured out a basic block for value")((BB && "Should have figured out a basic block for value"
) ? static_cast<void> (0) : __assert_fail ("BB && \"Should have figured out a basic block for value\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2848, __PRETTY_FUNCTION__))
;
2849 ValueDFS VDDef;
2850 DomTreeNode *DomNode = DT->getNode(BB);
2851 VDDef.DFSIn = DomNode->getDFSNumIn();
2852 VDDef.DFSOut = DomNode->getDFSNumOut();
2853 // If it's a store, use the leader of the value operand, if it's always
2854 // available, or the value operand. TODO: We could do dominance checks to
2855 // find a dominating leader, but not worth it ATM.
2856 if (auto *SI = dyn_cast<StoreInst>(D)) {
2857 auto Leader = lookupOperandLeader(SI->getValueOperand());
2858 if (alwaysAvailable(Leader)) {
2859 VDDef.Def.setPointer(Leader);
2860 } else {
2861 VDDef.Def.setPointer(SI->getValueOperand());
2862 VDDef.Def.setInt(true);
2863 }
2864 } else {
2865 VDDef.Def.setPointer(D);
2866 }
2867 assert(isa<Instruction>(D) &&((isa<Instruction>(D) && "The dense set member should always be an instruction"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(D) && \"The dense set member should always be an instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2868, __PRETTY_FUNCTION__))
2868 "The dense set member should always be an instruction")((isa<Instruction>(D) && "The dense set member should always be an instruction"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(D) && \"The dense set member should always be an instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2868, __PRETTY_FUNCTION__))
;
2869 VDDef.LocalNum = InstrToDFSNum(D);
2870 DFSOrderedSet.emplace_back(VDDef);
2871 Instruction *Def = cast<Instruction>(D);
2872 unsigned int UseCount = 0;
2873 // Now add the uses.
2874 for (auto &U : Def->uses()) {
2875 if (auto *I = dyn_cast<Instruction>(U.getUser())) {
2876 // Don't try to replace into dead uses
2877 if (InstructionsToErase.count(I))
2878 continue;
2879 ValueDFS VDUse;
2880 // Put the phi node uses in the incoming block.
2881 BasicBlock *IBlock;
2882 if (auto *P = dyn_cast<PHINode>(I)) {
2883 IBlock = P->getIncomingBlock(U);
2884 // Make phi node users appear last in the incoming block
2885 // they are from.
2886 VDUse.LocalNum = InstrDFS.size() + 1;
2887 } else {
2888 IBlock = I->getParent();
2889 VDUse.LocalNum = InstrToDFSNum(I);
2890 }
2891
2892 // Skip uses in unreachable blocks, as we're going
2893 // to delete them.
2894 if (ReachableBlocks.count(IBlock) == 0)
2895 continue;
2896
2897 DomTreeNode *DomNode = DT->getNode(IBlock);
2898 VDUse.DFSIn = DomNode->getDFSNumIn();
2899 VDUse.DFSOut = DomNode->getDFSNumOut();
2900 VDUse.U = &U;
2901 ++UseCount;
2902 DFSOrderedSet.emplace_back(VDUse);
2903 }
2904 }
2905
2906 // If there are no uses, it's probably dead (but it may have side-effects,
2907 // so not definitely dead. Otherwise, store the number of uses so we can
2908 // track if it becomes dead later).
2909 if (UseCount == 0)
2910 ProbablyDead.insert(Def);
2911 else
2912 UseCounts[Def] = UseCount;
2913 }
2914}
2915
2916// This function converts the set of members for a congruence class from values,
2917// to the set of defs for loads and stores, with associated DFS info.
2918void NewGVN::convertClassToLoadsAndStores(
2919 const CongruenceClass &Dense,
2920 SmallVectorImpl<ValueDFS> &LoadsAndStores) const {
2921 for (auto D : Dense) {
2922 if (!isa<LoadInst>(D) && !isa<StoreInst>(D))
2923 continue;
2924
2925 BasicBlock *BB = getBlockForValue(D);
2926 ValueDFS VD;
2927 DomTreeNode *DomNode = DT->getNode(BB);
2928 VD.DFSIn = DomNode->getDFSNumIn();
2929 VD.DFSOut = DomNode->getDFSNumOut();
2930 VD.Def.setPointer(D);
2931
2932 // If it's an instruction, use the real local dfs number.
2933 if (auto *I = dyn_cast<Instruction>(D))
2934 VD.LocalNum = InstrToDFSNum(I);
2935 else
2936 llvm_unreachable("Should have been an instruction")::llvm::llvm_unreachable_internal("Should have been an instruction"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 2936)
;
2937
2938 LoadsAndStores.emplace_back(VD);
2939 }
2940}
2941
2942static void patchReplacementInstruction(Instruction *I, Value *Repl) {
2943 auto *ReplInst = dyn_cast<Instruction>(Repl);
2944 if (!ReplInst)
2945 return;
2946
2947 // Patch the replacement so that it is not more restrictive than the value
2948 // being replaced.
2949 // Note that if 'I' is a load being replaced by some operation,
2950 // for example, by an arithmetic operation, then andIRFlags()
2951 // would just erase all math flags from the original arithmetic
2952 // operation, which is clearly not wanted and not needed.
2953 if (!isa<LoadInst>(I))
2954 ReplInst->andIRFlags(I);
2955
2956 // FIXME: If both the original and replacement value are part of the
2957 // same control-flow region (meaning that the execution of one
2958 // guarantees the execution of the other), then we can combine the
2959 // noalias scopes here and do better than the general conservative
2960 // answer used in combineMetadata().
2961
2962 // In general, GVN unifies expressions over different control-flow
2963 // regions, and so we need a conservative combination of the noalias
2964 // scopes.
2965 static const unsigned KnownIDs[] = {
2966 LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
2967 LLVMContext::MD_noalias, LLVMContext::MD_range,
2968 LLVMContext::MD_fpmath, LLVMContext::MD_invariant_load,
2969 LLVMContext::MD_invariant_group};
2970 combineMetadata(ReplInst, I, KnownIDs);
2971}
2972
2973static void patchAndReplaceAllUsesWith(Instruction *I, Value *Repl) {
2974 patchReplacementInstruction(I, Repl);
2975 I->replaceAllUsesWith(Repl);
2976}
2977
2978void NewGVN::deleteInstructionsInBlock(BasicBlock *BB) {
2979 DEBUG(dbgs() << " BasicBlock Dead:" << *BB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " BasicBlock Dead:" << *
BB; } } while (false)
;
2980 ++NumGVNBlocksDeleted;
2981
2982 // Delete the instructions backwards, as it has a reduced likelihood of having
2983 // to update as many def-use and use-def chains. Start after the terminator.
2984 auto StartPoint = BB->rbegin();
2985 ++StartPoint;
2986 // Note that we explicitly recalculate BB->rend() on each iteration,
2987 // as it may change when we remove the first instruction.
2988 for (BasicBlock::reverse_iterator I(StartPoint); I != BB->rend();) {
2989 Instruction &Inst = *I++;
2990 if (!Inst.use_empty())
2991 Inst.replaceAllUsesWith(UndefValue::get(Inst.getType()));
2992 if (isa<LandingPadInst>(Inst))
2993 continue;
2994
2995 Inst.eraseFromParent();
2996 ++NumGVNInstrDeleted;
2997 }
2998 // Now insert something that simplifycfg will turn into an unreachable.
2999 Type *Int8Ty = Type::getInt8Ty(BB->getContext());
3000 new StoreInst(UndefValue::get(Int8Ty),
3001 Constant::getNullValue(Int8Ty->getPointerTo()),
3002 BB->getTerminator());
3003}
3004
3005void NewGVN::markInstructionForDeletion(Instruction *I) {
3006 DEBUG(dbgs() << "Marking " << *I << " for deletion\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Marking " << *I <<
" for deletion\n"; } } while (false)
;
3007 InstructionsToErase.insert(I);
3008}
3009
3010void NewGVN::replaceInstruction(Instruction *I, Value *V) {
3011
3012 DEBUG(dbgs() << "Replacing " << *I << " with " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing " << *I <<
" with " << *V << "\n"; } } while (false)
;
3013 patchAndReplaceAllUsesWith(I, V);
3014 // We save the actual erasing to avoid invalidating memory
3015 // dependencies until we are done with everything.
3016 markInstructionForDeletion(I);
3017}
3018
3019namespace {
3020
3021// This is a stack that contains both the value and dfs info of where
3022// that value is valid.
3023class ValueDFSStack {
3024public:
3025 Value *back() const { return ValueStack.back(); }
3026 std::pair<int, int> dfs_back() const { return DFSStack.back(); }
3027
3028 void push_back(Value *V, int DFSIn, int DFSOut) {
3029 ValueStack.emplace_back(V);
3030 DFSStack.emplace_back(DFSIn, DFSOut);
3031 }
3032 bool empty() const { return DFSStack.empty(); }
3033 bool isInScope(int DFSIn, int DFSOut) const {
3034 if (empty())
3035 return false;
3036 return DFSIn >= DFSStack.back().first && DFSOut <= DFSStack.back().second;
3037 }
3038
3039 void popUntilDFSScope(int DFSIn, int DFSOut) {
3040
3041 // These two should always be in sync at this point.
3042 assert(ValueStack.size() == DFSStack.size() &&((ValueStack.size() == DFSStack.size() && "Mismatch between ValueStack and DFSStack"
) ? static_cast<void> (0) : __assert_fail ("ValueStack.size() == DFSStack.size() && \"Mismatch between ValueStack and DFSStack\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3043, __PRETTY_FUNCTION__))
3043 "Mismatch between ValueStack and DFSStack")((ValueStack.size() == DFSStack.size() && "Mismatch between ValueStack and DFSStack"
) ? static_cast<void> (0) : __assert_fail ("ValueStack.size() == DFSStack.size() && \"Mismatch between ValueStack and DFSStack\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3043, __PRETTY_FUNCTION__))
;
3044 while (
3045 !DFSStack.empty() &&
3046 !(DFSIn >= DFSStack.back().first && DFSOut <= DFSStack.back().second)) {
3047 DFSStack.pop_back();
3048 ValueStack.pop_back();
3049 }
3050 }
3051
3052private:
3053 SmallVector<Value *, 8> ValueStack;
3054 SmallVector<std::pair<int, int>, 8> DFSStack;
3055};
3056}
3057
3058bool NewGVN::eliminateInstructions(Function &F) {
3059 // This is a non-standard eliminator. The normal way to eliminate is
3060 // to walk the dominator tree in order, keeping track of available
3061 // values, and eliminating them. However, this is mildly
3062 // pointless. It requires doing lookups on every instruction,
3063 // regardless of whether we will ever eliminate it. For
3064 // instructions part of most singleton congruence classes, we know we
3065 // will never eliminate them.
3066
3067 // Instead, this eliminator looks at the congruence classes directly, sorts
3068 // them into a DFS ordering of the dominator tree, and then we just
3069 // perform elimination straight on the sets by walking the congruence
3070 // class member uses in order, and eliminate the ones dominated by the
3071 // last member. This is worst case O(E log E) where E = number of
3072 // instructions in a single congruence class. In theory, this is all
3073 // instructions. In practice, it is much faster, as most instructions are
3074 // either in singleton congruence classes or can't possibly be eliminated
3075 // anyway (if there are no overlapping DFS ranges in class).
3076 // When we find something not dominated, it becomes the new leader
3077 // for elimination purposes.
3078 // TODO: If we wanted to be faster, We could remove any members with no
3079 // overlapping ranges while sorting, as we will never eliminate anything
3080 // with those members, as they don't dominate anything else in our set.
3081
3082 bool AnythingReplaced = false;
3083
3084 // Since we are going to walk the domtree anyway, and we can't guarantee the
3085 // DFS numbers are updated, we compute some ourselves.
3086 DT->updateDFSNumbers();
3087
3088 for (auto &B : F) {
3089 if (!ReachableBlocks.count(&B)) {
3090 for (const auto S : successors(&B)) {
3091 for (auto II = S->begin(); isa<PHINode>(II); ++II) {
3092 auto &Phi = cast<PHINode>(*II);
3093 DEBUG(dbgs() << "Replacing incoming value of " << *II << " for block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing incoming value of " <<
*II << " for block " << getBlockName(&B) <<
" with undef due to it being unreachable\n"; } } while (false
)
3094 << getBlockName(&B)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing incoming value of " <<
*II << " for block " << getBlockName(&B) <<
" with undef due to it being unreachable\n"; } } while (false
)
3095 << " with undef due to it being unreachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing incoming value of " <<
*II << " for block " << getBlockName(&B) <<
" with undef due to it being unreachable\n"; } } while (false
)
;
3096 for (auto &Operand : Phi.incoming_values())
3097 if (Phi.getIncomingBlock(Operand) == &B)
3098 Operand.set(UndefValue::get(Phi.getType()));
3099 }
3100 }
3101 }
3102 }
3103
3104 // Map to store the use counts
3105 DenseMap<const Value *, unsigned int> UseCounts;
3106 for (CongruenceClass *CC : reverse(CongruenceClasses)) {
3107 // Track the equivalent store info so we can decide whether to try
3108 // dead store elimination.
3109 SmallVector<ValueDFS, 8> PossibleDeadStores;
3110 SmallPtrSet<Instruction *, 8> ProbablyDead;
3111 if (CC->isDead() || CC->empty())
3112 continue;
3113 // Everything still in the TOP class is unreachable or dead.
3114 if (CC == TOPClass) {
3115#ifndef NDEBUG
3116 for (auto M : *CC)
3117 assert((!ReachableBlocks.count(cast<Instruction>(M)->getParent()) ||(((!ReachableBlocks.count(cast<Instruction>(M)->getParent
()) || InstructionsToErase.count(cast<Instruction>(M)))
&& "Everything in TOP should be unreachable or dead at this "
"point") ? static_cast<void> (0) : __assert_fail ("(!ReachableBlocks.count(cast<Instruction>(M)->getParent()) || InstructionsToErase.count(cast<Instruction>(M))) && \"Everything in TOP should be unreachable or dead at this \" \"point\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3120, __PRETTY_FUNCTION__))
3118 InstructionsToErase.count(cast<Instruction>(M))) &&(((!ReachableBlocks.count(cast<Instruction>(M)->getParent
()) || InstructionsToErase.count(cast<Instruction>(M)))
&& "Everything in TOP should be unreachable or dead at this "
"point") ? static_cast<void> (0) : __assert_fail ("(!ReachableBlocks.count(cast<Instruction>(M)->getParent()) || InstructionsToErase.count(cast<Instruction>(M))) && \"Everything in TOP should be unreachable or dead at this \" \"point\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3120, __PRETTY_FUNCTION__))
3119 "Everything in TOP should be unreachable or dead at this "(((!ReachableBlocks.count(cast<Instruction>(M)->getParent
()) || InstructionsToErase.count(cast<Instruction>(M)))
&& "Everything in TOP should be unreachable or dead at this "
"point") ? static_cast<void> (0) : __assert_fail ("(!ReachableBlocks.count(cast<Instruction>(M)->getParent()) || InstructionsToErase.count(cast<Instruction>(M))) && \"Everything in TOP should be unreachable or dead at this \" \"point\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3120, __PRETTY_FUNCTION__))
3120 "point")(((!ReachableBlocks.count(cast<Instruction>(M)->getParent
()) || InstructionsToErase.count(cast<Instruction>(M)))
&& "Everything in TOP should be unreachable or dead at this "
"point") ? static_cast<void> (0) : __assert_fail ("(!ReachableBlocks.count(cast<Instruction>(M)->getParent()) || InstructionsToErase.count(cast<Instruction>(M))) && \"Everything in TOP should be unreachable or dead at this \" \"point\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3120, __PRETTY_FUNCTION__))
;
3121#endif
3122 continue;
3123 }
3124
3125 assert(CC->getLeader() && "We should have had a leader")((CC->getLeader() && "We should have had a leader"
) ? static_cast<void> (0) : __assert_fail ("CC->getLeader() && \"We should have had a leader\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3125, __PRETTY_FUNCTION__))
;
3126 // If this is a leader that is always available, and it's a
3127 // constant or has no equivalences, just replace everything with
3128 // it. We then update the congruence class with whatever members
3129 // are left.
3130 Value *Leader =
3131 CC->getStoredValue() ? CC->getStoredValue() : CC->getLeader();
3132 if (alwaysAvailable(Leader)) {
3133 CongruenceClass::MemberSet MembersLeft;
3134 for (auto M : *CC) {
3135 Value *Member = M;
3136 // Void things have no uses we can replace.
3137 if (Member == Leader || !isa<Instruction>(Member) ||
3138 Member->getType()->isVoidTy()) {
3139 MembersLeft.insert(Member);
3140 continue;
3141 }
3142 DEBUG(dbgs() << "Found replacement " << *(Leader) << " for " << *Memberdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
(Leader) << " for " << *Member << "\n"; } }
while (false)
3143 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
(Leader) << " for " << *Member << "\n"; } }
while (false)
;
3144 auto *I = cast<Instruction>(Member);
3145 assert(Leader != I && "About to accidentally remove our leader")((Leader != I && "About to accidentally remove our leader"
) ? static_cast<void> (0) : __assert_fail ("Leader != I && \"About to accidentally remove our leader\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3145, __PRETTY_FUNCTION__))
;
3146 replaceInstruction(I, Leader);
3147 AnythingReplaced = true;
3148 }
3149 CC->swap(MembersLeft);
3150 } else {
3151 DEBUG(dbgs() << "Eliminating in congruence class " << CC->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Eliminating in congruence class "
<< CC->getID() << "\n"; } } while (false)
3152 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Eliminating in congruence class "
<< CC->getID() << "\n"; } } while (false)
;
3153 // If this is a singleton, we can skip it.
3154 if (CC->size() != 1) {
3155 // This is a stack because equality replacement/etc may place
3156 // constants in the middle of the member list, and we want to use
3157 // those constant values in preference to the current leader, over
3158 // the scope of those constants.
3159 ValueDFSStack EliminationStack;
3160
3161 // Convert the members to DFS ordered sets and then merge them.
3162 SmallVector<ValueDFS, 8> DFSOrderedSet;
3163 convertClassToDFSOrdered(*CC, DFSOrderedSet, UseCounts, ProbablyDead);
3164
3165 // Sort the whole thing.
3166 std::sort(DFSOrderedSet.begin(), DFSOrderedSet.end());
3167 for (auto &VD : DFSOrderedSet) {
3168 int MemberDFSIn = VD.DFSIn;
3169 int MemberDFSOut = VD.DFSOut;
3170 Value *Def = VD.Def.getPointer();
3171 bool FromStore = VD.Def.getInt();
3172 Use *U = VD.U;
3173 // We ignore void things because we can't get a value from them.
3174 if (Def && Def->getType()->isVoidTy())
3175 continue;
3176
3177 if (EliminationStack.empty()) {
3178 DEBUG(dbgs() << "Elimination Stack is empty\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Elimination Stack is empty\n";
} } while (false)
;
3179 } else {
3180 DEBUG(dbgs() << "Elimination Stack Top DFS numbers are ("do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Elimination Stack Top DFS numbers are ("
<< EliminationStack.dfs_back().first << "," <<
EliminationStack.dfs_back().second << ")\n"; } } while
(false)
3181 << EliminationStack.dfs_back().first << ","do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Elimination Stack Top DFS numbers are ("
<< EliminationStack.dfs_back().first << "," <<
EliminationStack.dfs_back().second << ")\n"; } } while
(false)
3182 << EliminationStack.dfs_back().second << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Elimination Stack Top DFS numbers are ("
<< EliminationStack.dfs_back().first << "," <<
EliminationStack.dfs_back().second << ")\n"; } } while
(false)
;
3183 }
3184
3185 DEBUG(dbgs() << "Current DFS numbers are (" << MemberDFSIn << ","do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Current DFS numbers are (" <<
MemberDFSIn << "," << MemberDFSOut << ")\n"
; } } while (false)
3186 << MemberDFSOut << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Current DFS numbers are (" <<
MemberDFSIn << "," << MemberDFSOut << ")\n"
; } } while (false)
;
3187 // First, we see if we are out of scope or empty. If so,
3188 // and there equivalences, we try to replace the top of
3189 // stack with equivalences (if it's on the stack, it must
3190 // not have been eliminated yet).
3191 // Then we synchronize to our current scope, by
3192 // popping until we are back within a DFS scope that
3193 // dominates the current member.
3194 // Then, what happens depends on a few factors
3195 // If the stack is now empty, we need to push
3196 // If we have a constant or a local equivalence we want to
3197 // start using, we also push.
3198 // Otherwise, we walk along, processing members who are
3199 // dominated by this scope, and eliminate them.
3200 bool ShouldPush = Def && EliminationStack.empty();
3201 bool OutOfScope =
3202 !EliminationStack.isInScope(MemberDFSIn, MemberDFSOut);
3203
3204 if (OutOfScope || ShouldPush) {
3205 // Sync to our current scope.
3206 EliminationStack.popUntilDFSScope(MemberDFSIn, MemberDFSOut);
3207 bool ShouldPush = Def && EliminationStack.empty();
3208 if (ShouldPush) {
3209 EliminationStack.push_back(Def, MemberDFSIn, MemberDFSOut);
3210 }
3211 }
3212
3213 // Skip the Def's, we only want to eliminate on their uses. But mark
3214 // dominated defs as dead.
3215 if (Def) {
3216 // For anything in this case, what and how we value number
3217 // guarantees that any side-effets that would have occurred (ie
3218 // throwing, etc) can be proven to either still occur (because it's
3219 // dominated by something that has the same side-effects), or never
3220 // occur. Otherwise, we would not have been able to prove it value
3221 // equivalent to something else. For these things, we can just mark
3222 // it all dead. Note that this is different from the "ProbablyDead"
3223 // set, which may not be dominated by anything, and thus, are only
3224 // easy to prove dead if they are also side-effect free. Note that
3225 // because stores are put in terms of the stored value, we skip
3226 // stored values here. If the stored value is really dead, it will
3227 // still be marked for deletion when we process it in its own class.
3228 if (!EliminationStack.empty() && Def != EliminationStack.back() &&
3229 isa<Instruction>(Def) && !FromStore)
3230 markInstructionForDeletion(cast<Instruction>(Def));
3231 continue;
3232 }
3233 // At this point, we know it is a Use we are trying to possibly
3234 // replace.
3235
3236 assert(isa<Instruction>(U->get()) &&((isa<Instruction>(U->get()) && "Current def should have been an instruction"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(U->get()) && \"Current def should have been an instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3237, __PRETTY_FUNCTION__))
3237 "Current def should have been an instruction")((isa<Instruction>(U->get()) && "Current def should have been an instruction"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(U->get()) && \"Current def should have been an instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3237, __PRETTY_FUNCTION__))
;
3238 assert(isa<Instruction>(U->getUser()) &&((isa<Instruction>(U->getUser()) && "Current user should have been an instruction"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(U->getUser()) && \"Current user should have been an instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3239, __PRETTY_FUNCTION__))
3239 "Current user should have been an instruction")((isa<Instruction>(U->getUser()) && "Current user should have been an instruction"
) ? static_cast<void> (0) : __assert_fail ("isa<Instruction>(U->getUser()) && \"Current user should have been an instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3239, __PRETTY_FUNCTION__))
;
3240
3241 // If the thing we are replacing into is already marked to be dead,
3242 // this use is dead. Note that this is true regardless of whether
3243 // we have anything dominating the use or not. We do this here
3244 // because we are already walking all the uses anyway.
3245 Instruction *InstUse = cast<Instruction>(U->getUser());
3246 if (InstructionsToErase.count(InstUse)) {
3247 auto &UseCount = UseCounts[U->get()];
3248 if (--UseCount == 0) {
3249 ProbablyDead.insert(cast<Instruction>(U->get()));
3250 }
3251 }
3252
3253 // If we get to this point, and the stack is empty we must have a use
3254 // with nothing we can use to eliminate this use, so just skip it.
3255 if (EliminationStack.empty())
3256 continue;
3257
3258 Value *DominatingLeader = EliminationStack.back();
3259
3260 // Don't replace our existing users with ourselves.
3261 if (U->get() == DominatingLeader)
3262 continue;
3263 DEBUG(dbgs() << "Found replacement " << *DominatingLeader << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
DominatingLeader << " for " << *U->get() <<
" in " << *(U->getUser()) << "\n"; } } while (
false)
3264 << *U->get() << " in " << *(U->getUser()) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
DominatingLeader << " for " << *U->get() <<
" in " << *(U->getUser()) << "\n"; } } while (
false)
;
3265
3266 // If we replaced something in an instruction, handle the patching of
3267 // metadata. Skip this if we are replacing predicateinfo with its
3268 // original operand, as we already know we can just drop it.
3269 auto *ReplacedInst = cast<Instruction>(U->get());
3270 auto *PI = PredInfo->getPredicateInfoFor(ReplacedInst);
3271 if (!PI || DominatingLeader != PI->OriginalOp)
3272 patchReplacementInstruction(ReplacedInst, DominatingLeader);
3273 U->set(DominatingLeader);
3274 // This is now a use of the dominating leader, which means if the
3275 // dominating leader was dead, it's now live!
3276 auto &LeaderUseCount = UseCounts[DominatingLeader];
3277 // It's about to be alive again.
3278 if (LeaderUseCount == 0 && isa<Instruction>(DominatingLeader))
3279 ProbablyDead.erase(cast<Instruction>(DominatingLeader));
3280 ++LeaderUseCount;
3281 AnythingReplaced = true;
3282 }
3283 }
3284 }
3285
3286 // At this point, anything still in the ProbablyDead set is actually dead if
3287 // would be trivially dead.
3288 for (auto *I : ProbablyDead)
3289 if (wouldInstructionBeTriviallyDead(I))
3290 markInstructionForDeletion(I);
3291
3292 // Cleanup the congruence class.
3293 CongruenceClass::MemberSet MembersLeft;
3294 for (auto *Member : *CC)
3295 if (!isa<Instruction>(Member) ||
3296 !InstructionsToErase.count(cast<Instruction>(Member)))
3297 MembersLeft.insert(Member);
3298 CC->swap(MembersLeft);
3299
3300 // If we have possible dead stores to look at, try to eliminate them.
3301 if (CC->getStoreCount() > 0) {
3302 convertClassToLoadsAndStores(*CC, PossibleDeadStores);
3303 std::sort(PossibleDeadStores.begin(), PossibleDeadStores.end());
3304 ValueDFSStack EliminationStack;
3305 for (auto &VD : PossibleDeadStores) {
3306 int MemberDFSIn = VD.DFSIn;
3307 int MemberDFSOut = VD.DFSOut;
3308 Instruction *Member = cast<Instruction>(VD.Def.getPointer());
3309 if (EliminationStack.empty() ||
3310 !EliminationStack.isInScope(MemberDFSIn, MemberDFSOut)) {
3311 // Sync to our current scope.
3312 EliminationStack.popUntilDFSScope(MemberDFSIn, MemberDFSOut);
3313 if (EliminationStack.empty()) {
3314 EliminationStack.push_back(Member, MemberDFSIn, MemberDFSOut);
3315 continue;
3316 }
3317 }
3318 // We already did load elimination, so nothing to do here.
3319 if (isa<LoadInst>(Member))
3320 continue;
3321 assert(!EliminationStack.empty())((!EliminationStack.empty()) ? static_cast<void> (0) : __assert_fail
("!EliminationStack.empty()", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3321, __PRETTY_FUNCTION__))
;
3322 Instruction *Leader = cast<Instruction>(EliminationStack.back());
3323 (void)Leader;
3324 assert(DT->dominates(Leader->getParent(), Member->getParent()))((DT->dominates(Leader->getParent(), Member->getParent
())) ? static_cast<void> (0) : __assert_fail ("DT->dominates(Leader->getParent(), Member->getParent())"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn301769/lib/Transforms/Scalar/NewGVN.cpp"
, 3324, __PRETTY_FUNCTION__))
;
3325 // Member is dominater by Leader, and thus dead
3326 DEBUG(dbgs() << "Marking dead store " << *Memberdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Marking dead store " << *
Member << " that is dominated by " << *Leader <<
"\n"; } } while (false)
3327 << " that is dominated by " << *Leader << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Marking dead store " << *
Member << " that is dominated by " << *Leader <<
"\n"; } } while (false)
;
3328 markInstructionForDeletion(Member);
3329 CC->erase(Member);
3330 ++NumGVNDeadStores;
3331 }
3332 }
3333 }
3334
3335 return AnythingReplaced;
3336}
3337
3338// This function provides global ranking of operations so that we can place them
3339// in a canonical order. Note that rank alone is not necessarily enough for a
3340// complete ordering, as constants all have the same rank. However, generally,
3341// we will simplify an operation with all constants so that it doesn't matter
3342// what order they appear in.
3343unsigned int NewGVN::getRank(const Value *V) const {
3344 // Prefer undef to anything else
3345 if (isa<UndefValue>(V))
3346 return 0;
3347 if (isa<Constant>(V))
3348 return 1;
3349 else if (auto *A = dyn_cast<Argument>(V))
3350 return 2 + A->getArgNo();
3351
3352 // Need to shift the instruction DFS by number of arguments + 3 to account for
3353 // the constant and argument ranking above.
3354 unsigned Result = InstrToDFSNum(V);
3355 if (Result > 0)
3356 return 3 + NumFuncArgs + Result;
3357 // Unreachable or something else, just return a really large number.
3358 return ~0;
3359}
3360
3361// This is a function that says whether two commutative operations should
3362// have their order swapped when canonicalizing.
3363bool NewGVN::shouldSwapOperands(const Value *A, const Value *B) const {
3364 // Because we only care about a total ordering, and don't rewrite expressions
3365 // in this order, we order by rank, which will give a strict weak ordering to
3366 // everything but constants, and then we order by pointer address.
3367 return std::make_pair(getRank(A), A) > std::make_pair(getRank(B), B);
3368}
3369
3370class NewGVNLegacyPass : public FunctionPass {
3371public:
3372 static char ID; // Pass identification, replacement for typeid.
3373 NewGVNLegacyPass() : FunctionPass(ID) {
3374 initializeNewGVNLegacyPassPass(*PassRegistry::getPassRegistry());
3375 }
3376 bool runOnFunction(Function &F) override;
3377
3378private:
3379 void getAnalysisUsage(AnalysisUsage &AU) const override {
3380 AU.addRequired<AssumptionCacheTracker>();
3381 AU.addRequired<DominatorTreeWrapperPass>();
3382 AU.addRequired<TargetLibraryInfoWrapperPass>();
3383 AU.addRequired<MemorySSAWrapperPass>();
3384 AU.addRequired<AAResultsWrapperPass>();
3385 AU.addPreserved<DominatorTreeWrapperPass>();
3386 AU.addPreserved<GlobalsAAWrapperPass>();
3387 }
3388};
3389
3390bool NewGVNLegacyPass::runOnFunction(Function &F) {
3391 if (skipFunction(F))
3392 return false;
3393 return NewGVN(F, &getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
3394 &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F),
3395 &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(),
3396 &getAnalysis<AAResultsWrapperPass>().getAAResults(),
3397 &getAnalysis<MemorySSAWrapperPass>().getMSSA(),
3398 F.getParent()->getDataLayout())
3399 .runGVN();
3400}
3401
3402INITIALIZE_PASS_BEGIN(NewGVNLegacyPass, "newgvn", "Global Value Numbering",static void *initializeNewGVNLegacyPassPassOnce(PassRegistry &
Registry) {
3403 false, false)static void *initializeNewGVNLegacyPassPassOnce(PassRegistry &
Registry) {
3404INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
3405INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
3406INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
3407INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
3408INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
3409INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)initializeGlobalsAAWrapperPassPass(Registry);
3410INITIALIZE_PASS_END(NewGVNLegacyPass, "newgvn", "Global Value Numbering", false,PassInfo *PI = new PassInfo( "Global Value Numbering", "newgvn"
, &NewGVNLegacyPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<NewGVNLegacyPass>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeNewGVNLegacyPassPassFlag
; void llvm::initializeNewGVNLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeNewGVNLegacyPassPassFlag
, initializeNewGVNLegacyPassPassOnce, std::ref(Registry)); }
3411 false)PassInfo *PI = new PassInfo( "Global Value Numbering", "newgvn"
, &NewGVNLegacyPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<NewGVNLegacyPass>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeNewGVNLegacyPassPassFlag
; void llvm::initializeNewGVNLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeNewGVNLegacyPassPassFlag
, initializeNewGVNLegacyPassPassOnce, std::ref(Registry)); }
3412
3413char NewGVNLegacyPass::ID = 0;
3414
3415// createGVNPass - The public interface to this file.
3416FunctionPass *llvm::createNewGVNPass() { return new NewGVNLegacyPass(); }
3417
3418PreservedAnalyses NewGVNPass::run(Function &F, AnalysisManager<Function> &AM) {
3419 // Apparently the order in which we get these results matter for
3420 // the old GVN (see Chandler's comment in GVN.cpp). I'll keep
3421 // the same order here, just in case.
3422 auto &AC = AM.getResult<AssumptionAnalysis>(F);
3423 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
3424 auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
3425 auto &AA = AM.getResult<AAManager>(F);
3426 auto &MSSA = AM.getResult<MemorySSAAnalysis>(F).getMSSA();
3427 bool Changed =
3428 NewGVN(F, &DT, &AC, &TLI, &AA, &MSSA, F.getParent()->getDataLayout())
3429 .runGVN();
3430 if (!Changed)
3431 return PreservedAnalyses::all();
3432 PreservedAnalyses PA;
3433 PA.preserve<DominatorTreeAnalysis>();
3434 PA.preserve<GlobalsAA>();
3435 return PA;
3436}