Bug Summary

File:lib/Transforms/Scalar/NewGVN.cpp
Warning:line 987, column 3
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name NewGVN.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-9/lib/clang/9.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/lib/Transforms/Scalar -I /build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/include -I /build/llvm-toolchain-snapshot-9~svn362543/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/9.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-9/lib/clang/9.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/lib/Transforms/Scalar -fdebug-prefix-map=/build/llvm-toolchain-snapshot-9~svn362543=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2019-06-05-060531-1271-1 -x c++ /build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp -faddrsig
1//===- NewGVN.cpp - Global Value Numbering Pass ---------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9/// \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 vast majority of complexity and code
34/// in this file is devoted to tracking what value numbers could change for what
35/// instructions when various things happen. The rest of the algorithm is
36/// devoted to performing symbolic evaluation, forward propagation, and
37/// simplification of operations based on the value numbers deduced so far
38///
39/// In order to make the GVN mostly-complete, we use a technique derived from
40/// "Detection of Redundant Expressions: A Complete and Polynomial-time
41/// Algorithm in SSA" by R.R. Pai. The source of incompleteness in most SSA
42/// based GVN algorithms is related to their inability to detect equivalence
43/// between phi of ops (IE phi(a+b, c+d)) and op of phis (phi(a,c) + phi(b, d)).
44/// We resolve this issue by generating the equivalent "phi of ops" form for
45/// each op of phis we see, in a way that only takes polynomial time to resolve.
46///
47/// We also do not perform elimination by using any published algorithm. All
48/// published algorithms are O(Instructions). Instead, we use a technique that
49/// is O(number of operations with the same value number), enabling us to skip
50/// trying to eliminate things that have unique value numbers.
51//
52//===----------------------------------------------------------------------===//
53
54#include "llvm/Transforms/Scalar/NewGVN.h"
55#include "llvm/ADT/ArrayRef.h"
56#include "llvm/ADT/BitVector.h"
57#include "llvm/ADT/DenseMap.h"
58#include "llvm/ADT/DenseMapInfo.h"
59#include "llvm/ADT/DenseSet.h"
60#include "llvm/ADT/DepthFirstIterator.h"
61#include "llvm/ADT/GraphTraits.h"
62#include "llvm/ADT/Hashing.h"
63#include "llvm/ADT/PointerIntPair.h"
64#include "llvm/ADT/PostOrderIterator.h"
65#include "llvm/ADT/SmallPtrSet.h"
66#include "llvm/ADT/SmallVector.h"
67#include "llvm/ADT/SparseBitVector.h"
68#include "llvm/ADT/Statistic.h"
69#include "llvm/ADT/iterator_range.h"
70#include "llvm/Analysis/AliasAnalysis.h"
71#include "llvm/Analysis/AssumptionCache.h"
72#include "llvm/Analysis/CFGPrinter.h"
73#include "llvm/Analysis/ConstantFolding.h"
74#include "llvm/Analysis/GlobalsModRef.h"
75#include "llvm/Analysis/InstructionSimplify.h"
76#include "llvm/Analysis/MemoryBuiltins.h"
77#include "llvm/Analysis/MemorySSA.h"
78#include "llvm/Analysis/TargetLibraryInfo.h"
79#include "llvm/Transforms/Utils/Local.h"
80#include "llvm/IR/Argument.h"
81#include "llvm/IR/BasicBlock.h"
82#include "llvm/IR/Constant.h"
83#include "llvm/IR/Constants.h"
84#include "llvm/IR/Dominators.h"
85#include "llvm/IR/Function.h"
86#include "llvm/IR/InstrTypes.h"
87#include "llvm/IR/Instruction.h"
88#include "llvm/IR/Instructions.h"
89#include "llvm/IR/IntrinsicInst.h"
90#include "llvm/IR/Intrinsics.h"
91#include "llvm/IR/LLVMContext.h"
92#include "llvm/IR/Type.h"
93#include "llvm/IR/Use.h"
94#include "llvm/IR/User.h"
95#include "llvm/IR/Value.h"
96#include "llvm/Pass.h"
97#include "llvm/Support/Allocator.h"
98#include "llvm/Support/ArrayRecycler.h"
99#include "llvm/Support/Casting.h"
100#include "llvm/Support/CommandLine.h"
101#include "llvm/Support/Debug.h"
102#include "llvm/Support/DebugCounter.h"
103#include "llvm/Support/ErrorHandling.h"
104#include "llvm/Support/PointerLikeTypeTraits.h"
105#include "llvm/Support/raw_ostream.h"
106#include "llvm/Transforms/Scalar.h"
107#include "llvm/Transforms/Scalar/GVNExpression.h"
108#include "llvm/Transforms/Utils/PredicateInfo.h"
109#include "llvm/Transforms/Utils/VNCoercion.h"
110#include <algorithm>
111#include <cassert>
112#include <cstdint>
113#include <iterator>
114#include <map>
115#include <memory>
116#include <set>
117#include <string>
118#include <tuple>
119#include <utility>
120#include <vector>
121
122using namespace llvm;
123using namespace llvm::GVNExpression;
124using namespace llvm::VNCoercion;
125
126#define DEBUG_TYPE"newgvn" "newgvn"
127
128STATISTIC(NumGVNInstrDeleted, "Number of instructions deleted")static llvm::Statistic NumGVNInstrDeleted = {"newgvn", "NumGVNInstrDeleted"
, "Number of instructions deleted", {0}, {false}}
;
129STATISTIC(NumGVNBlocksDeleted, "Number of blocks deleted")static llvm::Statistic NumGVNBlocksDeleted = {"newgvn", "NumGVNBlocksDeleted"
, "Number of blocks deleted", {0}, {false}}
;
130STATISTIC(NumGVNOpsSimplified, "Number of Expressions simplified")static llvm::Statistic NumGVNOpsSimplified = {"newgvn", "NumGVNOpsSimplified"
, "Number of Expressions simplified", {0}, {false}}
;
131STATISTIC(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
}}
;
132STATISTIC(NumGVNMaxIterations,static llvm::Statistic NumGVNMaxIterations = {"newgvn", "NumGVNMaxIterations"
, "Maximum Number of iterations it took to converge GVN", {0}
, {false}}
133 "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}}
;
134STATISTIC(NumGVNLeaderChanges, "Number of leader changes")static llvm::Statistic NumGVNLeaderChanges = {"newgvn", "NumGVNLeaderChanges"
, "Number of leader changes", {0}, {false}}
;
135STATISTIC(NumGVNSortedLeaderChanges, "Number of sorted leader changes")static llvm::Statistic NumGVNSortedLeaderChanges = {"newgvn",
"NumGVNSortedLeaderChanges", "Number of sorted leader changes"
, {0}, {false}}
;
136STATISTIC(NumGVNAvoidedSortedLeaderChanges,static llvm::Statistic NumGVNAvoidedSortedLeaderChanges = {"newgvn"
, "NumGVNAvoidedSortedLeaderChanges", "Number of avoided sorted leader changes"
, {0}, {false}}
137 "Number of avoided sorted leader changes")static llvm::Statistic NumGVNAvoidedSortedLeaderChanges = {"newgvn"
, "NumGVNAvoidedSortedLeaderChanges", "Number of avoided sorted leader changes"
, {0}, {false}}
;
138STATISTIC(NumGVNDeadStores, "Number of redundant/dead stores eliminated")static llvm::Statistic NumGVNDeadStores = {"newgvn", "NumGVNDeadStores"
, "Number of redundant/dead stores eliminated", {0}, {false}}
;
139STATISTIC(NumGVNPHIOfOpsCreated, "Number of PHI of ops created")static llvm::Statistic NumGVNPHIOfOpsCreated = {"newgvn", "NumGVNPHIOfOpsCreated"
, "Number of PHI of ops created", {0}, {false}}
;
140STATISTIC(NumGVNPHIOfOpsEliminations,static llvm::Statistic NumGVNPHIOfOpsEliminations = {"newgvn"
, "NumGVNPHIOfOpsEliminations", "Number of things eliminated using PHI of ops"
, {0}, {false}}
141 "Number of things eliminated using PHI of ops")static llvm::Statistic NumGVNPHIOfOpsEliminations = {"newgvn"
, "NumGVNPHIOfOpsEliminations", "Number of things eliminated using PHI of ops"
, {0}, {false}}
;
142DEBUG_COUNTER(VNCounter, "newgvn-vn",static const unsigned VNCounter = DebugCounter::registerCounter
("newgvn-vn", "Controls which instructions are value numbered"
)
143 "Controls which instructions are value numbered")static const unsigned VNCounter = DebugCounter::registerCounter
("newgvn-vn", "Controls which instructions are value numbered"
)
;
144DEBUG_COUNTER(PHIOfOpsCounter, "newgvn-phi",static const unsigned PHIOfOpsCounter = DebugCounter::registerCounter
("newgvn-phi", "Controls which instructions we create phi of ops for"
)
145 "Controls which instructions we create phi of ops for")static const unsigned PHIOfOpsCounter = DebugCounter::registerCounter
("newgvn-phi", "Controls which instructions we create phi of ops for"
)
;
146// Currently store defining access refinement is too slow due to basicaa being
147// egregiously slow. This flag lets us keep it working while we work on this
148// issue.
149static cl::opt<bool> EnableStoreRefinement("enable-store-refinement",
150 cl::init(false), cl::Hidden);
151
152/// Currently, the generation "phi of ops" can result in correctness issues.
153static cl::opt<bool> EnablePhiOfOps("enable-phi-of-ops", cl::init(true),
154 cl::Hidden);
155
156//===----------------------------------------------------------------------===//
157// GVN Pass
158//===----------------------------------------------------------------------===//
159
160// Anchor methods.
161namespace llvm {
162namespace GVNExpression {
163
164Expression::~Expression() = default;
165BasicExpression::~BasicExpression() = default;
166CallExpression::~CallExpression() = default;
167LoadExpression::~LoadExpression() = default;
168StoreExpression::~StoreExpression() = default;
169AggregateValueExpression::~AggregateValueExpression() = default;
170PHIExpression::~PHIExpression() = default;
171
172} // end namespace GVNExpression
173} // end namespace llvm
174
175namespace {
176
177// Tarjan's SCC finding algorithm with Nuutila's improvements
178// SCCIterator is actually fairly complex for the simple thing we want.
179// It also wants to hand us SCC's that are unrelated to the phi node we ask
180// about, and have us process them there or risk redoing work.
181// Graph traits over a filter iterator also doesn't work that well here.
182// This SCC finder is specialized to walk use-def chains, and only follows
183// instructions,
184// not generic values (arguments, etc).
185struct TarjanSCC {
186 TarjanSCC() : Components(1) {}
187
188 void Start(const Instruction *Start) {
189 if (Root.lookup(Start) == 0)
190 FindSCC(Start);
191 }
192
193 const SmallPtrSetImpl<const Value *> &getComponentFor(const Value *V) const {
194 unsigned ComponentID = ValueToComponent.lookup(V);
195
196 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 197, __PRETTY_FUNCTION__))
197 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 197, __PRETTY_FUNCTION__))
;
198 return Components[ComponentID];
199 }
200
201private:
202 void FindSCC(const Instruction *I) {
203 Root[I] = ++DFSNum;
204 // Store the DFS Number we had before it possibly gets incremented.
205 unsigned int OurDFS = DFSNum;
206 for (auto &Op : I->operands()) {
207 if (auto *InstOp = dyn_cast<Instruction>(Op)) {
208 if (Root.lookup(Op) == 0)
209 FindSCC(InstOp);
210 if (!InComponent.count(Op))
211 Root[I] = std::min(Root.lookup(I), Root.lookup(Op));
212 }
213 }
214 // See if we really were the root of a component, by seeing if we still have
215 // our DFSNumber. If we do, we are the root of the component, and we have
216 // completed a component. If we do not, we are not the root of a component,
217 // and belong on the component stack.
218 if (Root.lookup(I) == OurDFS) {
219 unsigned ComponentID = Components.size();
220 Components.resize(Components.size() + 1);
221 auto &Component = Components.back();
222 Component.insert(I);
223 LLVM_DEBUG(dbgs() << "Component root is " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Component root is " << *
I << "\n"; } } while (false)
;
224 InComponent.insert(I);
225 ValueToComponent[I] = ComponentID;
226 // Pop a component off the stack and label it.
227 while (!Stack.empty() && Root.lookup(Stack.back()) >= OurDFS) {
228 auto *Member = Stack.back();
229 LLVM_DEBUG(dbgs() << "Component member is " << *Member << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Component member is " <<
*Member << "\n"; } } while (false)
;
230 Component.insert(Member);
231 InComponent.insert(Member);
232 ValueToComponent[Member] = ComponentID;
233 Stack.pop_back();
234 }
235 } else {
236 // Part of a component, push to stack
237 Stack.push_back(I);
238 }
239 }
240
241 unsigned int DFSNum = 1;
242 SmallPtrSet<const Value *, 8> InComponent;
243 DenseMap<const Value *, unsigned int> Root;
244 SmallVector<const Value *, 8> Stack;
245
246 // Store the components as vector of ptr sets, because we need the topo order
247 // of SCC's, but not individual member order
248 SmallVector<SmallPtrSet<const Value *, 8>, 8> Components;
249
250 DenseMap<const Value *, unsigned> ValueToComponent;
251};
252
253// Congruence classes represent the set of expressions/instructions
254// that are all the same *during some scope in the function*.
255// That is, because of the way we perform equality propagation, and
256// because of memory value numbering, it is not correct to assume
257// you can willy-nilly replace any member with any other at any
258// point in the function.
259//
260// For any Value in the Member set, it is valid to replace any dominated member
261// with that Value.
262//
263// Every congruence class has a leader, and the leader is used to symbolize
264// instructions in a canonical way (IE every operand of an instruction that is a
265// member of the same congruence class will always be replaced with leader
266// during symbolization). To simplify symbolization, we keep the leader as a
267// constant if class can be proved to be a constant value. Otherwise, the
268// leader is the member of the value set with the smallest DFS number. Each
269// congruence class also has a defining expression, though the expression may be
270// null. If it exists, it can be used for forward propagation and reassociation
271// of values.
272
273// For memory, we also track a representative MemoryAccess, and a set of memory
274// members for MemoryPhis (which have no real instructions). Note that for
275// memory, it seems tempting to try to split the memory members into a
276// MemoryCongruenceClass or something. Unfortunately, this does not work
277// easily. The value numbering of a given memory expression depends on the
278// leader of the memory congruence class, and the leader of memory congruence
279// class depends on the value numbering of a given memory expression. This
280// leads to wasted propagation, and in some cases, missed optimization. For
281// example: If we had value numbered two stores together before, but now do not,
282// we move them to a new value congruence class. This in turn will move at one
283// of the memorydefs to a new memory congruence class. Which in turn, affects
284// the value numbering of the stores we just value numbered (because the memory
285// congruence class is part of the value number). So while theoretically
286// possible to split them up, it turns out to be *incredibly* complicated to get
287// it to work right, because of the interdependency. While structurally
288// slightly messier, it is algorithmically much simpler and faster to do what we
289// do here, and track them both at once in the same class.
290// Note: The default iterators for this class iterate over values
291class CongruenceClass {
292public:
293 using MemberType = Value;
294 using MemberSet = SmallPtrSet<MemberType *, 4>;
295 using MemoryMemberType = MemoryPhi;
296 using MemoryMemberSet = SmallPtrSet<const MemoryMemberType *, 2>;
297
298 explicit CongruenceClass(unsigned ID) : ID(ID) {}
299 CongruenceClass(unsigned ID, Value *Leader, const Expression *E)
300 : ID(ID), RepLeader(Leader), DefiningExpr(E) {}
301
302 unsigned getID() const { return ID; }
303
304 // True if this class has no members left. This is mainly used for assertion
305 // purposes, and for skipping empty classes.
306 bool isDead() const {
307 // If it's both dead from a value perspective, and dead from a memory
308 // perspective, it's really dead.
309 return empty() && memory_empty();
310 }
311
312 // Leader functions
313 Value *getLeader() const { return RepLeader; }
314 void setLeader(Value *Leader) { RepLeader = Leader; }
315 const std::pair<Value *, unsigned int> &getNextLeader() const {
316 return NextLeader;
317 }
318 void resetNextLeader() { NextLeader = {nullptr, ~0}; }
319 void addPossibleNextLeader(std::pair<Value *, unsigned int> LeaderPair) {
320 if (LeaderPair.second < NextLeader.second)
321 NextLeader = LeaderPair;
322 }
323
324 Value *getStoredValue() const { return RepStoredValue; }
325 void setStoredValue(Value *Leader) { RepStoredValue = Leader; }
326 const MemoryAccess *getMemoryLeader() const { return RepMemoryAccess; }
327 void setMemoryLeader(const MemoryAccess *Leader) { RepMemoryAccess = Leader; }
328
329 // Forward propagation info
330 const Expression *getDefiningExpr() const { return DefiningExpr; }
331
332 // Value member set
333 bool empty() const { return Members.empty(); }
334 unsigned size() const { return Members.size(); }
335 MemberSet::const_iterator begin() const { return Members.begin(); }
336 MemberSet::const_iterator end() const { return Members.end(); }
337 void insert(MemberType *M) { Members.insert(M); }
338 void erase(MemberType *M) { Members.erase(M); }
339 void swap(MemberSet &Other) { Members.swap(Other); }
340
341 // Memory member set
342 bool memory_empty() const { return MemoryMembers.empty(); }
343 unsigned memory_size() const { return MemoryMembers.size(); }
344 MemoryMemberSet::const_iterator memory_begin() const {
345 return MemoryMembers.begin();
346 }
347 MemoryMemberSet::const_iterator memory_end() const {
348 return MemoryMembers.end();
349 }
350 iterator_range<MemoryMemberSet::const_iterator> memory() const {
351 return make_range(memory_begin(), memory_end());
352 }
353
354 void memory_insert(const MemoryMemberType *M) { MemoryMembers.insert(M); }
355 void memory_erase(const MemoryMemberType *M) { MemoryMembers.erase(M); }
356
357 // Store count
358 unsigned getStoreCount() const { return StoreCount; }
359 void incStoreCount() { ++StoreCount; }
360 void decStoreCount() {
361 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 361, __PRETTY_FUNCTION__))
;
362 --StoreCount;
363 }
364
365 // True if this class has no memory members.
366 bool definesNoMemory() const { return StoreCount == 0 && memory_empty(); }
367
368 // Return true if two congruence classes are equivalent to each other. This
369 // means that every field but the ID number and the dead field are equivalent.
370 bool isEquivalentTo(const CongruenceClass *Other) const {
371 if (!Other)
372 return false;
373 if (this == Other)
374 return true;
375
376 if (std::tie(StoreCount, RepLeader, RepStoredValue, RepMemoryAccess) !=
377 std::tie(Other->StoreCount, Other->RepLeader, Other->RepStoredValue,
378 Other->RepMemoryAccess))
379 return false;
380 if (DefiningExpr != Other->DefiningExpr)
381 if (!DefiningExpr || !Other->DefiningExpr ||
382 *DefiningExpr != *Other->DefiningExpr)
383 return false;
384
385 if (Members.size() != Other->Members.size())
386 return false;
387
388 return all_of(Members,
389 [&](const Value *V) { return Other->Members.count(V); });
390 }
391
392private:
393 unsigned ID;
394
395 // Representative leader.
396 Value *RepLeader = nullptr;
397
398 // The most dominating leader after our current leader, because the member set
399 // is not sorted and is expensive to keep sorted all the time.
400 std::pair<Value *, unsigned int> NextLeader = {nullptr, ~0U};
401
402 // If this is represented by a store, the value of the store.
403 Value *RepStoredValue = nullptr;
404
405 // If this class contains MemoryDefs or MemoryPhis, this is the leading memory
406 // access.
407 const MemoryAccess *RepMemoryAccess = nullptr;
408
409 // Defining Expression.
410 const Expression *DefiningExpr = nullptr;
411
412 // Actual members of this class.
413 MemberSet Members;
414
415 // This is the set of MemoryPhis that exist in the class. MemoryDefs and
416 // MemoryUses have real instructions representing them, so we only need to
417 // track MemoryPhis here.
418 MemoryMemberSet MemoryMembers;
419
420 // Number of stores in this congruence class.
421 // This is used so we can detect store equivalence changes properly.
422 int StoreCount = 0;
423};
424
425} // end anonymous namespace
426
427namespace llvm {
428
429struct ExactEqualsExpression {
430 const Expression &E;
431
432 explicit ExactEqualsExpression(const Expression &E) : E(E) {}
433
434 hash_code getComputedHash() const { return E.getComputedHash(); }
435
436 bool operator==(const Expression &Other) const {
437 return E.exactlyEquals(Other);
438 }
439};
440
441template <> struct DenseMapInfo<const Expression *> {
442 static const Expression *getEmptyKey() {
443 auto Val = static_cast<uintptr_t>(-1);
444 Val <<= PointerLikeTypeTraits<const Expression *>::NumLowBitsAvailable;
445 return reinterpret_cast<const Expression *>(Val);
446 }
447
448 static const Expression *getTombstoneKey() {
449 auto Val = static_cast<uintptr_t>(~1U);
450 Val <<= PointerLikeTypeTraits<const Expression *>::NumLowBitsAvailable;
451 return reinterpret_cast<const Expression *>(Val);
452 }
453
454 static unsigned getHashValue(const Expression *E) {
455 return E->getComputedHash();
456 }
457
458 static unsigned getHashValue(const ExactEqualsExpression &E) {
459 return E.getComputedHash();
460 }
461
462 static bool isEqual(const ExactEqualsExpression &LHS, const Expression *RHS) {
463 if (RHS == getTombstoneKey() || RHS == getEmptyKey())
464 return false;
465 return LHS == *RHS;
466 }
467
468 static bool isEqual(const Expression *LHS, const Expression *RHS) {
469 if (LHS == RHS)
470 return true;
471 if (LHS == getTombstoneKey() || RHS == getTombstoneKey() ||
472 LHS == getEmptyKey() || RHS == getEmptyKey())
473 return false;
474 // Compare hashes before equality. This is *not* what the hashtable does,
475 // since it is computing it modulo the number of buckets, whereas we are
476 // using the full hash keyspace. Since the hashes are precomputed, this
477 // check is *much* faster than equality.
478 if (LHS->getComputedHash() != RHS->getComputedHash())
479 return false;
480 return *LHS == *RHS;
481 }
482};
483
484} // end namespace llvm
485
486namespace {
487
488class NewGVN {
489 Function &F;
490 DominatorTree *DT;
491 const TargetLibraryInfo *TLI;
492 AliasAnalysis *AA;
493 MemorySSA *MSSA;
494 MemorySSAWalker *MSSAWalker;
495 const DataLayout &DL;
496 std::unique_ptr<PredicateInfo> PredInfo;
497
498 // These are the only two things the create* functions should have
499 // side-effects on due to allocating memory.
500 mutable BumpPtrAllocator ExpressionAllocator;
501 mutable ArrayRecycler<Value *> ArgRecycler;
502 mutable TarjanSCC SCCFinder;
503 const SimplifyQuery SQ;
504
505 // Number of function arguments, used by ranking
506 unsigned int NumFuncArgs;
507
508 // RPOOrdering of basic blocks
509 DenseMap<const DomTreeNode *, unsigned> RPOOrdering;
510
511 // Congruence class info.
512
513 // This class is called INITIAL in the paper. It is the class everything
514 // startsout in, and represents any value. Being an optimistic analysis,
515 // anything in the TOP class has the value TOP, which is indeterminate and
516 // equivalent to everything.
517 CongruenceClass *TOPClass;
518 std::vector<CongruenceClass *> CongruenceClasses;
519 unsigned NextCongruenceNum;
520
521 // Value Mappings.
522 DenseMap<Value *, CongruenceClass *> ValueToClass;
523 DenseMap<Value *, const Expression *> ValueToExpression;
524
525 // Value PHI handling, used to make equivalence between phi(op, op) and
526 // op(phi, phi).
527 // These mappings just store various data that would normally be part of the
528 // IR.
529 SmallPtrSet<const Instruction *, 8> PHINodeUses;
530
531 DenseMap<const Value *, bool> OpSafeForPHIOfOps;
532
533 // Map a temporary instruction we created to a parent block.
534 DenseMap<const Value *, BasicBlock *> TempToBlock;
535
536 // Map between the already in-program instructions and the temporary phis we
537 // created that they are known equivalent to.
538 DenseMap<const Value *, PHINode *> RealToTemp;
539
540 // In order to know when we should re-process instructions that have
541 // phi-of-ops, we track the set of expressions that they needed as
542 // leaders. When we discover new leaders for those expressions, we process the
543 // associated phi-of-op instructions again in case they have changed. The
544 // other way they may change is if they had leaders, and those leaders
545 // disappear. However, at the point they have leaders, there are uses of the
546 // relevant operands in the created phi node, and so they will get reprocessed
547 // through the normal user marking we perform.
548 mutable DenseMap<const Value *, SmallPtrSet<Value *, 2>> AdditionalUsers;
549 DenseMap<const Expression *, SmallPtrSet<Instruction *, 2>>
550 ExpressionToPhiOfOps;
551
552 // Map from temporary operation to MemoryAccess.
553 DenseMap<const Instruction *, MemoryUseOrDef *> TempToMemory;
554
555 // Set of all temporary instructions we created.
556 // Note: This will include instructions that were just created during value
557 // numbering. The way to test if something is using them is to check
558 // RealToTemp.
559 DenseSet<Instruction *> AllTempInstructions;
560
561 // This is the set of instructions to revisit on a reachability change. At
562 // the end of the main iteration loop it will contain at least all the phi of
563 // ops instructions that will be changed to phis, as well as regular phis.
564 // During the iteration loop, it may contain other things, such as phi of ops
565 // instructions that used edge reachability to reach a result, and so need to
566 // be revisited when the edge changes, independent of whether the phi they
567 // depended on changes.
568 DenseMap<BasicBlock *, SparseBitVector<>> RevisitOnReachabilityChange;
569
570 // Mapping from predicate info we used to the instructions we used it with.
571 // In order to correctly ensure propagation, we must keep track of what
572 // comparisons we used, so that when the values of the comparisons change, we
573 // propagate the information to the places we used the comparison.
574 mutable DenseMap<const Value *, SmallPtrSet<Instruction *, 2>>
575 PredicateToUsers;
576
577 // the same reasoning as PredicateToUsers. When we skip MemoryAccesses for
578 // stores, we no longer can rely solely on the def-use chains of MemorySSA.
579 mutable DenseMap<const MemoryAccess *, SmallPtrSet<MemoryAccess *, 2>>
580 MemoryToUsers;
581
582 // A table storing which memorydefs/phis represent a memory state provably
583 // equivalent to another memory state.
584 // We could use the congruence class machinery, but the MemoryAccess's are
585 // abstract memory states, so they can only ever be equivalent to each other,
586 // and not to constants, etc.
587 DenseMap<const MemoryAccess *, CongruenceClass *> MemoryAccessToClass;
588
589 // We could, if we wanted, build MemoryPhiExpressions and
590 // MemoryVariableExpressions, etc, and value number them the same way we value
591 // number phi expressions. For the moment, this seems like overkill. They
592 // can only exist in one of three states: they can be TOP (equal to
593 // everything), Equivalent to something else, or unique. Because we do not
594 // create expressions for them, we need to simulate leader change not just
595 // when they change class, but when they change state. Note: We can do the
596 // same thing for phis, and avoid having phi expressions if we wanted, We
597 // should eventually unify in one direction or the other, so this is a little
598 // bit of an experiment in which turns out easier to maintain.
599 enum MemoryPhiState { MPS_Invalid, MPS_TOP, MPS_Equivalent, MPS_Unique };
600 DenseMap<const MemoryPhi *, MemoryPhiState> MemoryPhiState;
601
602 enum InstCycleState { ICS_Unknown, ICS_CycleFree, ICS_Cycle };
603 mutable DenseMap<const Instruction *, InstCycleState> InstCycleState;
604
605 // Expression to class mapping.
606 using ExpressionClassMap = DenseMap<const Expression *, CongruenceClass *>;
607 ExpressionClassMap ExpressionToClass;
608
609 // We have a single expression that represents currently DeadExpressions.
610 // For dead expressions we can prove will stay dead, we mark them with
611 // DFS number zero. However, it's possible in the case of phi nodes
612 // for us to assume/prove all arguments are dead during fixpointing.
613 // We use DeadExpression for that case.
614 DeadExpression *SingletonDeadExpression = nullptr;
615
616 // Which values have changed as a result of leader changes.
617 SmallPtrSet<Value *, 8> LeaderChanges;
618
619 // Reachability info.
620 using BlockEdge = BasicBlockEdge;
621 DenseSet<BlockEdge> ReachableEdges;
622 SmallPtrSet<const BasicBlock *, 8> ReachableBlocks;
623
624 // This is a bitvector because, on larger functions, we may have
625 // thousands of touched instructions at once (entire blocks,
626 // instructions with hundreds of uses, etc). Even with optimization
627 // for when we mark whole blocks as touched, when this was a
628 // SmallPtrSet or DenseSet, for some functions, we spent >20% of all
629 // the time in GVN just managing this list. The bitvector, on the
630 // other hand, efficiently supports test/set/clear of both
631 // individual and ranges, as well as "find next element" This
632 // enables us to use it as a worklist with essentially 0 cost.
633 BitVector TouchedInstructions;
634
635 DenseMap<const BasicBlock *, std::pair<unsigned, unsigned>> BlockInstRange;
636
637#ifndef NDEBUG
638 // Debugging for how many times each block and instruction got processed.
639 DenseMap<const Value *, unsigned> ProcessedCount;
640#endif
641
642 // DFS info.
643 // This contains a mapping from Instructions to DFS numbers.
644 // The numbering starts at 1. An instruction with DFS number zero
645 // means that the instruction is dead.
646 DenseMap<const Value *, unsigned> InstrDFS;
647
648 // This contains the mapping DFS numbers to instructions.
649 SmallVector<Value *, 32> DFSToInstr;
650
651 // Deletion info.
652 SmallPtrSet<Instruction *, 8> InstructionsToErase;
653
654public:
655 NewGVN(Function &F, DominatorTree *DT, AssumptionCache *AC,
656 TargetLibraryInfo *TLI, AliasAnalysis *AA, MemorySSA *MSSA,
657 const DataLayout &DL)
658 : F(F), DT(DT), TLI(TLI), AA(AA), MSSA(MSSA), DL(DL),
659 PredInfo(make_unique<PredicateInfo>(F, *DT, *AC)),
660 SQ(DL, TLI, DT, AC, /*CtxI=*/nullptr, /*UseInstrInfo=*/false) {}
661
662 bool runGVN();
663
664private:
665 // Expression handling.
666 const Expression *createExpression(Instruction *) const;
667 const Expression *createBinaryExpression(unsigned, Type *, Value *, Value *,
668 Instruction *) const;
669
670 // Our canonical form for phi arguments is a pair of incoming value, incoming
671 // basic block.
672 using ValPair = std::pair<Value *, BasicBlock *>;
673
674 PHIExpression *createPHIExpression(ArrayRef<ValPair>, const Instruction *,
675 BasicBlock *, bool &HasBackEdge,
676 bool &OriginalOpsConstant) const;
677 const DeadExpression *createDeadExpression() const;
678 const VariableExpression *createVariableExpression(Value *) const;
679 const ConstantExpression *createConstantExpression(Constant *) const;
680 const Expression *createVariableOrConstant(Value *V) const;
681 const UnknownExpression *createUnknownExpression(Instruction *) const;
682 const StoreExpression *createStoreExpression(StoreInst *,
683 const MemoryAccess *) const;
684 LoadExpression *createLoadExpression(Type *, Value *, LoadInst *,
685 const MemoryAccess *) const;
686 const CallExpression *createCallExpression(CallInst *,
687 const MemoryAccess *) const;
688 const AggregateValueExpression *
689 createAggregateValueExpression(Instruction *) const;
690 bool setBasicExpressionInfo(Instruction *, BasicExpression *) const;
691
692 // Congruence class handling.
693 CongruenceClass *createCongruenceClass(Value *Leader, const Expression *E) {
694 auto *result = new CongruenceClass(NextCongruenceNum++, Leader, E);
695 CongruenceClasses.emplace_back(result);
696 return result;
697 }
698
699 CongruenceClass *createMemoryClass(MemoryAccess *MA) {
700 auto *CC = createCongruenceClass(nullptr, nullptr);
701 CC->setMemoryLeader(MA);
702 return CC;
703 }
704
705 CongruenceClass *ensureLeaderOfMemoryClass(MemoryAccess *MA) {
706 auto *CC = getMemoryClass(MA);
707 if (CC->getMemoryLeader() != MA)
708 CC = createMemoryClass(MA);
709 return CC;
710 }
711
712 CongruenceClass *createSingletonCongruenceClass(Value *Member) {
713 CongruenceClass *CClass = createCongruenceClass(Member, nullptr);
714 CClass->insert(Member);
715 ValueToClass[Member] = CClass;
716 return CClass;
717 }
718
719 void initializeCongruenceClasses(Function &F);
720 const Expression *makePossiblePHIOfOps(Instruction *,
721 SmallPtrSetImpl<Value *> &);
722 Value *findLeaderForInst(Instruction *ValueOp,
723 SmallPtrSetImpl<Value *> &Visited,
724 MemoryAccess *MemAccess, Instruction *OrigInst,
725 BasicBlock *PredBB);
726 bool OpIsSafeForPHIOfOpsHelper(Value *V, const BasicBlock *PHIBlock,
727 SmallPtrSetImpl<const Value *> &Visited,
728 SmallVectorImpl<Instruction *> &Worklist);
729 bool OpIsSafeForPHIOfOps(Value *Op, const BasicBlock *PHIBlock,
730 SmallPtrSetImpl<const Value *> &);
731 void addPhiOfOps(PHINode *Op, BasicBlock *BB, Instruction *ExistingValue);
732 void removePhiOfOps(Instruction *I, PHINode *PHITemp);
733
734 // Value number an Instruction or MemoryPhi.
735 void valueNumberMemoryPhi(MemoryPhi *);
736 void valueNumberInstruction(Instruction *);
737
738 // Symbolic evaluation.
739 const Expression *checkSimplificationResults(Expression *, Instruction *,
740 Value *) const;
741 const Expression *performSymbolicEvaluation(Value *,
742 SmallPtrSetImpl<Value *> &) const;
743 const Expression *performSymbolicLoadCoercion(Type *, Value *, LoadInst *,
744 Instruction *,
745 MemoryAccess *) const;
746 const Expression *performSymbolicLoadEvaluation(Instruction *) const;
747 const Expression *performSymbolicStoreEvaluation(Instruction *) const;
748 const Expression *performSymbolicCallEvaluation(Instruction *) const;
749 void sortPHIOps(MutableArrayRef<ValPair> Ops) const;
750 const Expression *performSymbolicPHIEvaluation(ArrayRef<ValPair>,
751 Instruction *I,
752 BasicBlock *PHIBlock) const;
753 const Expression *performSymbolicAggrValueEvaluation(Instruction *) const;
754 const Expression *performSymbolicCmpEvaluation(Instruction *) const;
755 const Expression *performSymbolicPredicateInfoEvaluation(Instruction *) const;
756
757 // Congruence finding.
758 bool someEquivalentDominates(const Instruction *, const Instruction *) const;
759 Value *lookupOperandLeader(Value *) const;
760 CongruenceClass *getClassForExpression(const Expression *E) const;
761 void performCongruenceFinding(Instruction *, const Expression *);
762 void moveValueToNewCongruenceClass(Instruction *, const Expression *,
763 CongruenceClass *, CongruenceClass *);
764 void moveMemoryToNewCongruenceClass(Instruction *, MemoryAccess *,
765 CongruenceClass *, CongruenceClass *);
766 Value *getNextValueLeader(CongruenceClass *) const;
767 const MemoryAccess *getNextMemoryLeader(CongruenceClass *) const;
768 bool setMemoryClass(const MemoryAccess *From, CongruenceClass *To);
769 CongruenceClass *getMemoryClass(const MemoryAccess *MA) const;
770 const MemoryAccess *lookupMemoryLeader(const MemoryAccess *) const;
771 bool isMemoryAccessTOP(const MemoryAccess *) const;
772
773 // Ranking
774 unsigned int getRank(const Value *) const;
775 bool shouldSwapOperands(const Value *, const Value *) const;
776
777 // Reachability handling.
778 void updateReachableEdge(BasicBlock *, BasicBlock *);
779 void processOutgoingEdges(Instruction *, BasicBlock *);
780 Value *findConditionEquivalence(Value *) const;
781
782 // Elimination.
783 struct ValueDFS;
784 void convertClassToDFSOrdered(const CongruenceClass &,
785 SmallVectorImpl<ValueDFS> &,
786 DenseMap<const Value *, unsigned int> &,
787 SmallPtrSetImpl<Instruction *> &) const;
788 void convertClassToLoadsAndStores(const CongruenceClass &,
789 SmallVectorImpl<ValueDFS> &) const;
790
791 bool eliminateInstructions(Function &);
792 void replaceInstruction(Instruction *, Value *);
793 void markInstructionForDeletion(Instruction *);
794 void deleteInstructionsInBlock(BasicBlock *);
795 Value *findPHIOfOpsLeader(const Expression *, const Instruction *,
796 const BasicBlock *) const;
797
798 // New instruction creation.
799 void handleNewInstruction(Instruction *) {}
800
801 // Various instruction touch utilities
802 template <typename Map, typename KeyType, typename Func>
803 void for_each_found(Map &, const KeyType &, Func);
804 template <typename Map, typename KeyType>
805 void touchAndErase(Map &, const KeyType &);
806 void markUsersTouched(Value *);
807 void markMemoryUsersTouched(const MemoryAccess *);
808 void markMemoryDefTouched(const MemoryAccess *);
809 void markPredicateUsersTouched(Instruction *);
810 void markValueLeaderChangeTouched(CongruenceClass *CC);
811 void markMemoryLeaderChangeTouched(CongruenceClass *CC);
812 void markPhiOfOpsChanged(const Expression *E);
813 void addPredicateUsers(const PredicateBase *, Instruction *) const;
814 void addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) const;
815 void addAdditionalUsers(Value *To, Value *User) const;
816
817 // Main loop of value numbering
818 void iterateTouchedInstructions();
819
820 // Utilities.
821 void cleanupTables();
822 std::pair<unsigned, unsigned> assignDFSNumbers(BasicBlock *, unsigned);
823 void updateProcessedCount(const Value *V);
824 void verifyMemoryCongruency() const;
825 void verifyIterationSettled(Function &F);
826 void verifyStoreExpressions() const;
827 bool singleReachablePHIPath(SmallPtrSet<const MemoryAccess *, 8> &,
828 const MemoryAccess *, const MemoryAccess *) const;
829 BasicBlock *getBlockForValue(Value *V) const;
830 void deleteExpression(const Expression *E) const;
831 MemoryUseOrDef *getMemoryAccess(const Instruction *) const;
832 MemoryAccess *getDefiningAccess(const MemoryAccess *) const;
833 MemoryPhi *getMemoryAccess(const BasicBlock *) const;
834 template <class T, class Range> T *getMinDFSOfRange(const Range &) const;
835
836 unsigned InstrToDFSNum(const Value *V) const {
837 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 837, __PRETTY_FUNCTION__))
;
838 return InstrDFS.lookup(V);
839 }
840
841 unsigned InstrToDFSNum(const MemoryAccess *MA) const {
842 return MemoryToDFSNum(MA);
843 }
844
845 Value *InstrFromDFSNum(unsigned DFSNum) { return DFSToInstr[DFSNum]; }
846
847 // Given a MemoryAccess, return the relevant instruction DFS number. Note:
848 // This deliberately takes a value so it can be used with Use's, which will
849 // auto-convert to Value's but not to MemoryAccess's.
850 unsigned MemoryToDFSNum(const Value *MA) const {
851 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 852, __PRETTY_FUNCTION__))
852 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 852, __PRETTY_FUNCTION__))
;
853 return isa<MemoryUseOrDef>(MA)
854 ? InstrToDFSNum(cast<MemoryUseOrDef>(MA)->getMemoryInst())
855 : InstrDFS.lookup(MA);
856 }
857
858 bool isCycleFree(const Instruction *) const;
859 bool isBackedge(BasicBlock *From, BasicBlock *To) const;
860
861 // Debug counter info. When verifying, we have to reset the value numbering
862 // debug counter to the same state it started in to get the same results.
863 int64_t StartingVNCounter;
864};
865
866} // end anonymous namespace
867
868template <typename T>
869static bool equalsLoadStoreHelper(const T &LHS, const Expression &RHS) {
870 if (!isa<LoadExpression>(RHS) && !isa<StoreExpression>(RHS))
871 return false;
872 return LHS.MemoryExpression::equals(RHS);
873}
874
875bool LoadExpression::equals(const Expression &Other) const {
876 return equalsLoadStoreHelper(*this, Other);
877}
878
879bool StoreExpression::equals(const Expression &Other) const {
880 if (!equalsLoadStoreHelper(*this, Other))
881 return false;
882 // Make sure that store vs store includes the value operand.
883 if (const auto *S = dyn_cast<StoreExpression>(&Other))
884 if (getStoredValue() != S->getStoredValue())
885 return false;
886 return true;
887}
888
889// Determine if the edge From->To is a backedge
890bool NewGVN::isBackedge(BasicBlock *From, BasicBlock *To) const {
891 return From == To ||
892 RPOOrdering.lookup(DT->getNode(From)) >=
893 RPOOrdering.lookup(DT->getNode(To));
894}
895
896#ifndef NDEBUG
897static std::string getBlockName(const BasicBlock *B) {
898 return DOTGraphTraits<const Function *>::getSimpleNodeLabel(B, nullptr);
899}
900#endif
901
902// Get a MemoryAccess for an instruction, fake or real.
903MemoryUseOrDef *NewGVN::getMemoryAccess(const Instruction *I) const {
904 auto *Result = MSSA->getMemoryAccess(I);
905 return Result ? Result : TempToMemory.lookup(I);
906}
907
908// Get a MemoryPhi for a basic block. These are all real.
909MemoryPhi *NewGVN::getMemoryAccess(const BasicBlock *BB) const {
910 return MSSA->getMemoryAccess(BB);
911}
912
913// Get the basic block from an instruction/memory value.
914BasicBlock *NewGVN::getBlockForValue(Value *V) const {
915 if (auto *I = dyn_cast<Instruction>(V)) {
916 auto *Parent = I->getParent();
917 if (Parent)
918 return Parent;
919 Parent = TempToBlock.lookup(V);
920 assert(Parent && "Every fake instruction should have a block")((Parent && "Every fake instruction should have a block"
) ? static_cast<void> (0) : __assert_fail ("Parent && \"Every fake instruction should have a block\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 920, __PRETTY_FUNCTION__))
;
921 return Parent;
922 }
923
924 auto *MP = dyn_cast<MemoryPhi>(V);
925 assert(MP && "Should have been an instruction or a MemoryPhi")((MP && "Should have been an instruction or a MemoryPhi"
) ? static_cast<void> (0) : __assert_fail ("MP && \"Should have been an instruction or a MemoryPhi\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 925, __PRETTY_FUNCTION__))
;
926 return MP->getBlock();
927}
928
929// Delete a definitely dead expression, so it can be reused by the expression
930// allocator. Some of these are not in creation functions, so we have to accept
931// const versions.
932void NewGVN::deleteExpression(const Expression *E) const {
933 assert(isa<BasicExpression>(E))((isa<BasicExpression>(E)) ? static_cast<void> (0
) : __assert_fail ("isa<BasicExpression>(E)", "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 933, __PRETTY_FUNCTION__))
;
934 auto *BE = cast<BasicExpression>(E);
935 const_cast<BasicExpression *>(BE)->deallocateOperands(ArgRecycler);
936 ExpressionAllocator.Deallocate(E);
937}
938
939// If V is a predicateinfo copy, get the thing it is a copy of.
940static Value *getCopyOf(const Value *V) {
941 if (auto *II = dyn_cast<IntrinsicInst>(V))
942 if (II->getIntrinsicID() == Intrinsic::ssa_copy)
943 return II->getOperand(0);
944 return nullptr;
945}
946
947// Return true if V is really PN, even accounting for predicateinfo copies.
948static bool isCopyOfPHI(const Value *V, const PHINode *PN) {
949 return V == PN || getCopyOf(V) == PN;
950}
951
952static bool isCopyOfAPHI(const Value *V) {
953 auto *CO = getCopyOf(V);
954 return CO && isa<PHINode>(CO);
955}
956
957// Sort PHI Operands into a canonical order. What we use here is an RPO
958// order. The BlockInstRange numbers are generated in an RPO walk of the basic
959// blocks.
960void NewGVN::sortPHIOps(MutableArrayRef<ValPair> Ops) const {
961 llvm::sort(Ops, [&](const ValPair &P1, const ValPair &P2) {
962 return BlockInstRange.lookup(P1.second).first <
963 BlockInstRange.lookup(P2.second).first;
964 });
965}
966
967// Return true if V is a value that will always be available (IE can
968// be placed anywhere) in the function. We don't do globals here
969// because they are often worse to put in place.
970static bool alwaysAvailable(Value *V) {
971 return isa<Constant>(V) || isa<Argument>(V);
972}
973
974// Create a PHIExpression from an array of {incoming edge, value} pairs. I is
975// the original instruction we are creating a PHIExpression for (but may not be
976// a phi node). We require, as an invariant, that all the PHIOperands in the
977// same block are sorted the same way. sortPHIOps will sort them into a
978// canonical order.
979PHIExpression *NewGVN::createPHIExpression(ArrayRef<ValPair> PHIOperands,
980 const Instruction *I,
981 BasicBlock *PHIBlock,
982 bool &HasBackedge,
983 bool &OriginalOpsConstant) const {
984 unsigned NumOps = PHIOperands.size();
985 auto *E = new (ExpressionAllocator) PHIExpression(NumOps, PHIBlock);
23
'E' initialized to a null pointer value
986
987 E->allocateOperands(ArgRecycler, ExpressionAllocator);
24
Called C++ object pointer is null
988 E->setType(PHIOperands.begin()->first->getType());
989 E->setOpcode(Instruction::PHI);
990
991 // Filter out unreachable phi operands.
992 auto Filtered = make_filter_range(PHIOperands, [&](const ValPair &P) {
993 auto *BB = P.second;
994 if (auto *PHIOp = dyn_cast<PHINode>(I))
995 if (isCopyOfPHI(P.first, PHIOp))
996 return false;
997 if (!ReachableEdges.count({BB, PHIBlock}))
998 return false;
999 // Things in TOPClass are equivalent to everything.
1000 if (ValueToClass.lookup(P.first) == TOPClass)
1001 return false;
1002 OriginalOpsConstant = OriginalOpsConstant && isa<Constant>(P.first);
1003 HasBackedge = HasBackedge || isBackedge(BB, PHIBlock);
1004 return lookupOperandLeader(P.first) != I;
1005 });
1006 std::transform(Filtered.begin(), Filtered.end(), op_inserter(E),
1007 [&](const ValPair &P) -> Value * {
1008 return lookupOperandLeader(P.first);
1009 });
1010 return E;
1011}
1012
1013// Set basic expression info (Arguments, type, opcode) for Expression
1014// E from Instruction I in block B.
1015bool NewGVN::setBasicExpressionInfo(Instruction *I, BasicExpression *E) const {
1016 bool AllConstant = true;
1017 if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
1018 E->setType(GEP->getSourceElementType());
1019 else
1020 E->setType(I->getType());
1021 E->setOpcode(I->getOpcode());
1022 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1023
1024 // Transform the operand array into an operand leader array, and keep track of
1025 // whether all members are constant.
1026 std::transform(I->op_begin(), I->op_end(), op_inserter(E), [&](Value *O) {
1027 auto Operand = lookupOperandLeader(O);
1028 AllConstant = AllConstant && isa<Constant>(Operand);
1029 return Operand;
1030 });
1031
1032 return AllConstant;
1033}
1034
1035const Expression *NewGVN::createBinaryExpression(unsigned Opcode, Type *T,
1036 Value *Arg1, Value *Arg2,
1037 Instruction *I) const {
1038 auto *E = new (ExpressionAllocator) BasicExpression(2);
1039
1040 E->setType(T);
1041 E->setOpcode(Opcode);
1042 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1043 if (Instruction::isCommutative(Opcode)) {
1044 // Ensure that commutative instructions that only differ by a permutation
1045 // of their operands get the same value number by sorting the operand value
1046 // numbers. Since all commutative instructions have two operands it is more
1047 // efficient to sort by hand rather than using, say, std::sort.
1048 if (shouldSwapOperands(Arg1, Arg2))
1049 std::swap(Arg1, Arg2);
1050 }
1051 E->op_push_back(lookupOperandLeader(Arg1));
1052 E->op_push_back(lookupOperandLeader(Arg2));
1053
1054 Value *V = SimplifyBinOp(Opcode, E->getOperand(0), E->getOperand(1), SQ);
1055 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1056 return SimplifiedE;
1057 return E;
1058}
1059
1060// Take a Value returned by simplification of Expression E/Instruction
1061// I, and see if it resulted in a simpler expression. If so, return
1062// that expression.
1063const Expression *NewGVN::checkSimplificationResults(Expression *E,
1064 Instruction *I,
1065 Value *V) const {
1066 if (!V)
1067 return nullptr;
1068 if (auto *C = dyn_cast<Constant>(V)) {
1069 if (I)
1070 LLVM_DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " constant " << *C << "\n"; } } while
(false)
1071 << " constant " << *C << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " constant " << *C << "\n"; } } while
(false)
;
1072 NumGVNOpsSimplified++;
1073 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1074, __PRETTY_FUNCTION__))
1074 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1074, __PRETTY_FUNCTION__))
;
1075 deleteExpression(E);
1076 return createConstantExpression(C);
1077 } else if (isa<Argument>(V) || isa<GlobalVariable>(V)) {
1078 if (I)
1079 LLVM_DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " variable " << *V << "\n"; } } while
(false)
1080 << " variable " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " variable " << *V << "\n"; } } while
(false)
;
1081 deleteExpression(E);
1082 return createVariableExpression(V);
1083 }
1084
1085 CongruenceClass *CC = ValueToClass.lookup(V);
1086 if (CC) {
1087 if (CC->getLeader() && CC->getLeader() != I) {
1088 // If we simplified to something else, we need to communicate
1089 // that we're users of the value we simplified to.
1090 if (I != V) {
1091 // Don't add temporary instructions to the user lists.
1092 if (!AllTempInstructions.count(I))
1093 addAdditionalUsers(V, I);
1094 }
1095 return createVariableOrConstant(CC->getLeader());
1096 }
1097 if (CC->getDefiningExpr()) {
1098 // If we simplified to something else, we need to communicate
1099 // that we're users of the value we simplified to.
1100 if (I != V) {
1101 // Don't add temporary instructions to the user lists.
1102 if (!AllTempInstructions.count(I))
1103 addAdditionalUsers(V, I);
1104 }
1105
1106 if (I)
1107 LLVM_DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " expression " << *CC->getDefiningExpr
() << "\n"; } } while (false)
1108 << " expression " << *CC->getDefiningExpr() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " expression " << *CC->getDefiningExpr
() << "\n"; } } while (false)
;
1109 NumGVNOpsSimplified++;
1110 deleteExpression(E);
1111 return CC->getDefiningExpr();
1112 }
1113 }
1114
1115 return nullptr;
1116}
1117
1118// Create a value expression from the instruction I, replacing operands with
1119// their leaders.
1120
1121const Expression *NewGVN::createExpression(Instruction *I) const {
1122 auto *E = new (ExpressionAllocator) BasicExpression(I->getNumOperands());
1123
1124 bool AllConstant = setBasicExpressionInfo(I, E);
1125
1126 if (I->isCommutative()) {
1127 // Ensure that commutative instructions that only differ by a permutation
1128 // of their operands get the same value number by sorting the operand value
1129 // numbers. Since all commutative instructions have two operands it is more
1130 // efficient to sort by hand rather than using, say, std::sort.
1131 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!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1131, __PRETTY_FUNCTION__))
;
1132 if (shouldSwapOperands(E->getOperand(0), E->getOperand(1)))
1133 E->swapOperands(0, 1);
1134 }
1135 // Perform simplification.
1136 if (auto *CI = dyn_cast<CmpInst>(I)) {
1137 // Sort the operand value numbers so x<y and y>x get the same value
1138 // number.
1139 CmpInst::Predicate Predicate = CI->getPredicate();
1140 if (shouldSwapOperands(E->getOperand(0), E->getOperand(1))) {
1141 E->swapOperands(0, 1);
1142 Predicate = CmpInst::getSwappedPredicate(Predicate);
1143 }
1144 E->setOpcode((CI->getOpcode() << 8) | Predicate);
1145 // TODO: 25% of our time is spent in SimplifyCmpInst with pointer operands
1146 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1147, __PRETTY_FUNCTION__))
1147 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1147, __PRETTY_FUNCTION__))
;
1148 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())"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1149, __PRETTY_FUNCTION__))
1149 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())"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1149, __PRETTY_FUNCTION__))
;
1150 Value *V =
1151 SimplifyCmpInst(Predicate, E->getOperand(0), E->getOperand(1), SQ);
1152 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1153 return SimplifiedE;
1154 } else if (isa<SelectInst>(I)) {
1155 if (isa<Constant>(E->getOperand(0)) ||
1156 E->getOperand(1) == E->getOperand(2)) {
1157 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()"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1158, __PRETTY_FUNCTION__))
1158 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()"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1158, __PRETTY_FUNCTION__))
;
1159 Value *V = SimplifySelectInst(E->getOperand(0), E->getOperand(1),
1160 E->getOperand(2), SQ);
1161 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1162 return SimplifiedE;
1163 }
1164 } else if (I->isBinaryOp()) {
1165 Value *V =
1166 SimplifyBinOp(E->getOpcode(), E->getOperand(0), E->getOperand(1), SQ);
1167 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1168 return SimplifiedE;
1169 } else if (auto *BI = dyn_cast<BitCastInst>(I)) {
1170 Value *V =
1171 SimplifyCastInst(BI->getOpcode(), BI->getOperand(0), BI->getType(), SQ);
1172 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1173 return SimplifiedE;
1174 } else if (isa<GetElementPtrInst>(I)) {
1175 Value *V = SimplifyGEPInst(
1176 E->getType(), ArrayRef<Value *>(E->op_begin(), E->op_end()), SQ);
1177 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1178 return SimplifiedE;
1179 } else if (AllConstant) {
1180 // We don't bother trying to simplify unless all of the operands
1181 // were constant.
1182 // TODO: There are a lot of Simplify*'s we could call here, if we
1183 // wanted to. The original motivating case for this code was a
1184 // zext i1 false to i8, which we don't have an interface to
1185 // simplify (IE there is no SimplifyZExt).
1186
1187 SmallVector<Constant *, 8> C;
1188 for (Value *Arg : E->operands())
1189 C.emplace_back(cast<Constant>(Arg));
1190
1191 if (Value *V = ConstantFoldInstOperands(I, C, DL, TLI))
1192 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1193 return SimplifiedE;
1194 }
1195 return E;
1196}
1197
1198const AggregateValueExpression *
1199NewGVN::createAggregateValueExpression(Instruction *I) const {
1200 if (auto *II = dyn_cast<InsertValueInst>(I)) {
1201 auto *E = new (ExpressionAllocator)
1202 AggregateValueExpression(I->getNumOperands(), II->getNumIndices());
1203 setBasicExpressionInfo(I, E);
1204 E->allocateIntOperands(ExpressionAllocator);
1205 std::copy(II->idx_begin(), II->idx_end(), int_op_inserter(E));
1206 return E;
1207 } else if (auto *EI = dyn_cast<ExtractValueInst>(I)) {
1208 auto *E = new (ExpressionAllocator)
1209 AggregateValueExpression(I->getNumOperands(), EI->getNumIndices());
1210 setBasicExpressionInfo(EI, E);
1211 E->allocateIntOperands(ExpressionAllocator);
1212 std::copy(EI->idx_begin(), EI->idx_end(), int_op_inserter(E));
1213 return E;
1214 }
1215 llvm_unreachable("Unhandled type of aggregate value operation")::llvm::llvm_unreachable_internal("Unhandled type of aggregate value operation"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1215)
;
1216}
1217
1218const DeadExpression *NewGVN::createDeadExpression() const {
1219 // DeadExpression has no arguments and all DeadExpression's are the same,
1220 // so we only need one of them.
1221 return SingletonDeadExpression;
1222}
1223
1224const VariableExpression *NewGVN::createVariableExpression(Value *V) const {
1225 auto *E = new (ExpressionAllocator) VariableExpression(V);
1226 E->setOpcode(V->getValueID());
1227 return E;
1228}
1229
1230const Expression *NewGVN::createVariableOrConstant(Value *V) const {
1231 if (auto *C = dyn_cast<Constant>(V))
1232 return createConstantExpression(C);
1233 return createVariableExpression(V);
1234}
1235
1236const ConstantExpression *NewGVN::createConstantExpression(Constant *C) const {
1237 auto *E = new (ExpressionAllocator) ConstantExpression(C);
1238 E->setOpcode(C->getValueID());
1239 return E;
1240}
1241
1242const UnknownExpression *NewGVN::createUnknownExpression(Instruction *I) const {
1243 auto *E = new (ExpressionAllocator) UnknownExpression(I);
1244 E->setOpcode(I->getOpcode());
1245 return E;
1246}
1247
1248const CallExpression *
1249NewGVN::createCallExpression(CallInst *CI, const MemoryAccess *MA) const {
1250 // FIXME: Add operand bundles for calls.
1251 auto *E =
1252 new (ExpressionAllocator) CallExpression(CI->getNumOperands(), CI, MA);
1253 setBasicExpressionInfo(CI, E);
1254 return E;
1255}
1256
1257// Return true if some equivalent of instruction Inst dominates instruction U.
1258bool NewGVN::someEquivalentDominates(const Instruction *Inst,
1259 const Instruction *U) const {
1260 auto *CC = ValueToClass.lookup(Inst);
1261 // This must be an instruction because we are only called from phi nodes
1262 // in the case that the value it needs to check against is an instruction.
1263
1264 // The most likely candidates for dominance are the leader and the next leader.
1265 // The leader or nextleader will dominate in all cases where there is an
1266 // equivalent that is higher up in the dom tree.
1267 // We can't *only* check them, however, because the
1268 // dominator tree could have an infinite number of non-dominating siblings
1269 // with instructions that are in the right congruence class.
1270 // A
1271 // B C D E F G
1272 // |
1273 // H
1274 // Instruction U could be in H, with equivalents in every other sibling.
1275 // Depending on the rpo order picked, the leader could be the equivalent in
1276 // any of these siblings.
1277 if (!CC)
1278 return false;
1279 if (alwaysAvailable(CC->getLeader()))
1280 return true;
1281 if (DT->dominates(cast<Instruction>(CC->getLeader()), U))
1282 return true;
1283 if (CC->getNextLeader().first &&
1284 DT->dominates(cast<Instruction>(CC->getNextLeader().first), U))
1285 return true;
1286 return llvm::any_of(*CC, [&](const Value *Member) {
1287 return Member != CC->getLeader() &&
1288 DT->dominates(cast<Instruction>(Member), U);
1289 });
1290}
1291
1292// See if we have a congruence class and leader for this operand, and if so,
1293// return it. Otherwise, return the operand itself.
1294Value *NewGVN::lookupOperandLeader(Value *V) const {
1295 CongruenceClass *CC = ValueToClass.lookup(V);
1296 if (CC) {
1297 // Everything in TOP is represented by undef, as it can be any value.
1298 // We do have to make sure we get the type right though, so we can't set the
1299 // RepLeader to undef.
1300 if (CC == TOPClass)
1301 return UndefValue::get(V->getType());
1302 return CC->getStoredValue() ? CC->getStoredValue() : CC->getLeader();
1303 }
1304
1305 return V;
1306}
1307
1308const MemoryAccess *NewGVN::lookupMemoryLeader(const MemoryAccess *MA) const {
1309 auto *CC = getMemoryClass(MA);
1310 assert(CC->getMemoryLeader() &&((CC->getMemoryLeader() && "Every MemoryAccess should be mapped to a congruence class with a "
"representative memory access") ? static_cast<void> (0
) : __assert_fail ("CC->getMemoryLeader() && \"Every MemoryAccess should be mapped to a congruence class with a \" \"representative memory access\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1312, __PRETTY_FUNCTION__))
1311 "Every MemoryAccess should be mapped to a congruence class with a "((CC->getMemoryLeader() && "Every MemoryAccess should be mapped to a congruence class with a "
"representative memory access") ? static_cast<void> (0
) : __assert_fail ("CC->getMemoryLeader() && \"Every MemoryAccess should be mapped to a congruence class with a \" \"representative memory access\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1312, __PRETTY_FUNCTION__))
1312 "representative memory access")((CC->getMemoryLeader() && "Every MemoryAccess should be mapped to a congruence class with a "
"representative memory access") ? static_cast<void> (0
) : __assert_fail ("CC->getMemoryLeader() && \"Every MemoryAccess should be mapped to a congruence class with a \" \"representative memory access\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1312, __PRETTY_FUNCTION__))
;
1313 return CC->getMemoryLeader();
1314}
1315
1316// Return true if the MemoryAccess is really equivalent to everything. This is
1317// equivalent to the lattice value "TOP" in most lattices. This is the initial
1318// state of all MemoryAccesses.
1319bool NewGVN::isMemoryAccessTOP(const MemoryAccess *MA) const {
1320 return getMemoryClass(MA) == TOPClass;
1321}
1322
1323LoadExpression *NewGVN::createLoadExpression(Type *LoadType, Value *PointerOp,
1324 LoadInst *LI,
1325 const MemoryAccess *MA) const {
1326 auto *E =
1327 new (ExpressionAllocator) LoadExpression(1, LI, lookupMemoryLeader(MA));
1328 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1329 E->setType(LoadType);
1330
1331 // Give store and loads same opcode so they value number together.
1332 E->setOpcode(0);
1333 E->op_push_back(PointerOp);
1334 if (LI)
1335 E->setAlignment(LI->getAlignment());
1336
1337 // TODO: Value number heap versions. We may be able to discover
1338 // things alias analysis can't on it's own (IE that a store and a
1339 // load have the same value, and thus, it isn't clobbering the load).
1340 return E;
1341}
1342
1343const StoreExpression *
1344NewGVN::createStoreExpression(StoreInst *SI, const MemoryAccess *MA) const {
1345 auto *StoredValueLeader = lookupOperandLeader(SI->getValueOperand());
1346 auto *E = new (ExpressionAllocator)
1347 StoreExpression(SI->getNumOperands(), SI, StoredValueLeader, MA);
1348 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1349 E->setType(SI->getValueOperand()->getType());
1350
1351 // Give store and loads same opcode so they value number together.
1352 E->setOpcode(0);
1353 E->op_push_back(lookupOperandLeader(SI->getPointerOperand()));
1354
1355 // TODO: Value number heap versions. We may be able to discover
1356 // things alias analysis can't on it's own (IE that a store and a
1357 // load have the same value, and thus, it isn't clobbering the load).
1358 return E;
1359}
1360
1361const Expression *NewGVN::performSymbolicStoreEvaluation(Instruction *I) const {
1362 // Unlike loads, we never try to eliminate stores, so we do not check if they
1363 // are simple and avoid value numbering them.
1364 auto *SI = cast<StoreInst>(I);
1365 auto *StoreAccess = getMemoryAccess(SI);
1366 // Get the expression, if any, for the RHS of the MemoryDef.
1367 const MemoryAccess *StoreRHS = StoreAccess->getDefiningAccess();
1368 if (EnableStoreRefinement)
1369 StoreRHS = MSSAWalker->getClobberingMemoryAccess(StoreAccess);
1370 // If we bypassed the use-def chains, make sure we add a use.
1371 StoreRHS = lookupMemoryLeader(StoreRHS);
1372 if (StoreRHS != StoreAccess->getDefiningAccess())
1373 addMemoryUsers(StoreRHS, StoreAccess);
1374 // If we are defined by ourselves, use the live on entry def.
1375 if (StoreRHS == StoreAccess)
1376 StoreRHS = MSSA->getLiveOnEntryDef();
1377
1378 if (SI->isSimple()) {
1379 // See if we are defined by a previous store expression, it already has a
1380 // value, and it's the same value as our current store. FIXME: Right now, we
1381 // only do this for simple stores, we should expand to cover memcpys, etc.
1382 const auto *LastStore = createStoreExpression(SI, StoreRHS);
1383 const auto *LastCC = ExpressionToClass.lookup(LastStore);
1384 // We really want to check whether the expression we matched was a store. No
1385 // easy way to do that. However, we can check that the class we found has a
1386 // store, which, assuming the value numbering state is not corrupt, is
1387 // sufficient, because we must also be equivalent to that store's expression
1388 // for it to be in the same class as the load.
1389 if (LastCC && LastCC->getStoredValue() == LastStore->getStoredValue())
1390 return LastStore;
1391 // Also check if our value operand is defined by a load of the same memory
1392 // location, and the memory state is the same as it was then (otherwise, it
1393 // could have been overwritten later. See test32 in
1394 // transforms/DeadStoreElimination/simple.ll).
1395 if (auto *LI = dyn_cast<LoadInst>(LastStore->getStoredValue()))
1396 if ((lookupOperandLeader(LI->getPointerOperand()) ==
1397 LastStore->getOperand(0)) &&
1398 (lookupMemoryLeader(getMemoryAccess(LI)->getDefiningAccess()) ==
1399 StoreRHS))
1400 return LastStore;
1401 deleteExpression(LastStore);
1402 }
1403
1404 // If the store is not equivalent to anything, value number it as a store that
1405 // produces a unique memory state (instead of using it's MemoryUse, we use
1406 // it's MemoryDef).
1407 return createStoreExpression(SI, StoreAccess);
1408}
1409
1410// See if we can extract the value of a loaded pointer from a load, a store, or
1411// a memory instruction.
1412const Expression *
1413NewGVN::performSymbolicLoadCoercion(Type *LoadType, Value *LoadPtr,
1414 LoadInst *LI, Instruction *DepInst,
1415 MemoryAccess *DefiningAccess) const {
1416 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1416, __PRETTY_FUNCTION__))
;
1417 if (auto *DepSI = dyn_cast<StoreInst>(DepInst)) {
1418 // Can't forward from non-atomic to atomic without violating memory model.
1419 // Also don't need to coerce if they are the same type, we will just
1420 // propagate.
1421 if (LI->isAtomic() > DepSI->isAtomic() ||
1422 LoadType == DepSI->getValueOperand()->getType())
1423 return nullptr;
1424 int Offset = analyzeLoadFromClobberingStore(LoadType, LoadPtr, DepSI, DL);
1425 if (Offset >= 0) {
1426 if (auto *C = dyn_cast<Constant>(
1427 lookupOperandLeader(DepSI->getValueOperand()))) {
1428 LLVM_DEBUG(dbgs() << "Coercing load from store " << *DepSIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from store " <<
*DepSI << " to constant " << *C << "\n"; }
} while (false)
1429 << " to constant " << *C << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from store " <<
*DepSI << " to constant " << *C << "\n"; }
} while (false)
;
1430 return createConstantExpression(
1431 getConstantStoreValueForLoad(C, Offset, LoadType, DL));
1432 }
1433 }
1434 } else if (auto *DepLI = dyn_cast<LoadInst>(DepInst)) {
1435 // Can't forward from non-atomic to atomic without violating memory model.
1436 if (LI->isAtomic() > DepLI->isAtomic())
1437 return nullptr;
1438 int Offset = analyzeLoadFromClobberingLoad(LoadType, LoadPtr, DepLI, DL);
1439 if (Offset >= 0) {
1440 // We can coerce a constant load into a load.
1441 if (auto *C = dyn_cast<Constant>(lookupOperandLeader(DepLI)))
1442 if (auto *PossibleConstant =
1443 getConstantLoadValueForLoad(C, Offset, LoadType, DL)) {
1444 LLVM_DEBUG(dbgs() << "Coercing load from load " << *LIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from load " <<
*LI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
1445 << " to constant " << *PossibleConstant << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from load " <<
*LI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
;
1446 return createConstantExpression(PossibleConstant);
1447 }
1448 }
1449 } else if (auto *DepMI = dyn_cast<MemIntrinsic>(DepInst)) {
1450 int Offset = analyzeLoadFromClobberingMemInst(LoadType, LoadPtr, DepMI, DL);
1451 if (Offset >= 0) {
1452 if (auto *PossibleConstant =
1453 getConstantMemInstValueForLoad(DepMI, Offset, LoadType, DL)) {
1454 LLVM_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)
1455 << " to constant " << *PossibleConstant << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from meminst " <<
*DepMI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
;
1456 return createConstantExpression(PossibleConstant);
1457 }
1458 }
1459 }
1460
1461 // All of the below are only true if the loaded pointer is produced
1462 // by the dependent instruction.
1463 if (LoadPtr != lookupOperandLeader(DepInst) &&
1464 !AA->isMustAlias(LoadPtr, DepInst))
1465 return nullptr;
1466 // If this load really doesn't depend on anything, then we must be loading an
1467 // undef value. This can happen when loading for a fresh allocation with no
1468 // intervening stores, for example. Note that this is only true in the case
1469 // that the result of the allocation is pointer equal to the load ptr.
1470 if (isa<AllocaInst>(DepInst) || isMallocLikeFn(DepInst, TLI)) {
1471 return createConstantExpression(UndefValue::get(LoadType));
1472 }
1473 // If this load occurs either right after a lifetime begin,
1474 // then the loaded value is undefined.
1475 else if (auto *II = dyn_cast<IntrinsicInst>(DepInst)) {
1476 if (II->getIntrinsicID() == Intrinsic::lifetime_start)
1477 return createConstantExpression(UndefValue::get(LoadType));
1478 }
1479 // If this load follows a calloc (which zero initializes memory),
1480 // then the loaded value is zero
1481 else if (isCallocLikeFn(DepInst, TLI)) {
1482 return createConstantExpression(Constant::getNullValue(LoadType));
1483 }
1484
1485 return nullptr;
1486}
1487
1488const Expression *NewGVN::performSymbolicLoadEvaluation(Instruction *I) const {
1489 auto *LI = cast<LoadInst>(I);
1490
1491 // We can eliminate in favor of non-simple loads, but we won't be able to
1492 // eliminate the loads themselves.
1493 if (!LI->isSimple())
1494 return nullptr;
1495
1496 Value *LoadAddressLeader = lookupOperandLeader(LI->getPointerOperand());
1497 // Load of undef is undef.
1498 if (isa<UndefValue>(LoadAddressLeader))
1499 return createConstantExpression(UndefValue::get(LI->getType()));
1500 MemoryAccess *OriginalAccess = getMemoryAccess(I);
1501 MemoryAccess *DefiningAccess =
1502 MSSAWalker->getClobberingMemoryAccess(OriginalAccess);
1503
1504 if (!MSSA->isLiveOnEntryDef(DefiningAccess)) {
1505 if (auto *MD = dyn_cast<MemoryDef>(DefiningAccess)) {
1506 Instruction *DefiningInst = MD->getMemoryInst();
1507 // If the defining instruction is not reachable, replace with undef.
1508 if (!ReachableBlocks.count(DefiningInst->getParent()))
1509 return createConstantExpression(UndefValue::get(LI->getType()));
1510 // This will handle stores and memory insts. We only do if it the
1511 // defining access has a different type, or it is a pointer produced by
1512 // certain memory operations that cause the memory to have a fixed value
1513 // (IE things like calloc).
1514 if (const auto *CoercionResult =
1515 performSymbolicLoadCoercion(LI->getType(), LoadAddressLeader, LI,
1516 DefiningInst, DefiningAccess))
1517 return CoercionResult;
1518 }
1519 }
1520
1521 const auto *LE = createLoadExpression(LI->getType(), LoadAddressLeader, LI,
1522 DefiningAccess);
1523 // If our MemoryLeader is not our defining access, add a use to the
1524 // MemoryLeader, so that we get reprocessed when it changes.
1525 if (LE->getMemoryLeader() != DefiningAccess)
1526 addMemoryUsers(LE->getMemoryLeader(), OriginalAccess);
1527 return LE;
1528}
1529
1530const Expression *
1531NewGVN::performSymbolicPredicateInfoEvaluation(Instruction *I) const {
1532 auto *PI = PredInfo->getPredicateInfoFor(I);
1533 if (!PI)
1534 return nullptr;
1535
1536 LLVM_DEBUG(dbgs() << "Found predicate info from instruction !\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found predicate info from instruction !\n"
; } } while (false)
;
1537
1538 auto *PWC = dyn_cast<PredicateWithCondition>(PI);
1539 if (!PWC)
1540 return nullptr;
1541
1542 auto *CopyOf = I->getOperand(0);
1543 auto *Cond = PWC->Condition;
1544
1545 // If this a copy of the condition, it must be either true or false depending
1546 // on the predicate info type and edge.
1547 if (CopyOf == Cond) {
1548 // We should not need to add predicate users because the predicate info is
1549 // already a use of this operand.
1550 if (isa<PredicateAssume>(PI))
1551 return createConstantExpression(ConstantInt::getTrue(Cond->getType()));
1552 if (auto *PBranch = dyn_cast<PredicateBranch>(PI)) {
1553 if (PBranch->TrueEdge)
1554 return createConstantExpression(ConstantInt::getTrue(Cond->getType()));
1555 return createConstantExpression(ConstantInt::getFalse(Cond->getType()));
1556 }
1557 if (auto *PSwitch = dyn_cast<PredicateSwitch>(PI))
1558 return createConstantExpression(cast<Constant>(PSwitch->CaseValue));
1559 }
1560
1561 // Not a copy of the condition, so see what the predicates tell us about this
1562 // value. First, though, we check to make sure the value is actually a copy
1563 // of one of the condition operands. It's possible, in certain cases, for it
1564 // to be a copy of a predicateinfo copy. In particular, if two branch
1565 // operations use the same condition, and one branch dominates the other, we
1566 // will end up with a copy of a copy. This is currently a small deficiency in
1567 // predicateinfo. What will end up happening here is that we will value
1568 // number both copies the same anyway.
1569
1570 // Everything below relies on the condition being a comparison.
1571 auto *Cmp = dyn_cast<CmpInst>(Cond);
1572 if (!Cmp)
1573 return nullptr;
1574
1575 if (CopyOf != Cmp->getOperand(0) && CopyOf != Cmp->getOperand(1)) {
1576 LLVM_DEBUG(dbgs() << "Copy is not of any condition operands!\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Copy is not of any condition operands!\n"
; } } while (false)
;
1577 return nullptr;
1578 }
1579 Value *FirstOp = lookupOperandLeader(Cmp->getOperand(0));
1580 Value *SecondOp = lookupOperandLeader(Cmp->getOperand(1));
1581 bool SwappedOps = false;
1582 // Sort the ops.
1583 if (shouldSwapOperands(FirstOp, SecondOp)) {
1584 std::swap(FirstOp, SecondOp);
1585 SwappedOps = true;
1586 }
1587 CmpInst::Predicate Predicate =
1588 SwappedOps ? Cmp->getSwappedPredicate() : Cmp->getPredicate();
1589
1590 if (isa<PredicateAssume>(PI)) {
1591 // If we assume the operands are equal, then they are equal.
1592 if (Predicate == CmpInst::ICMP_EQ) {
1593 addPredicateUsers(PI, I);
1594 addAdditionalUsers(SwappedOps ? Cmp->getOperand(1) : Cmp->getOperand(0),
1595 I);
1596 return createVariableOrConstant(FirstOp);
1597 }
1598 }
1599 if (const auto *PBranch = dyn_cast<PredicateBranch>(PI)) {
1600 // If we are *not* a copy of the comparison, we may equal to the other
1601 // operand when the predicate implies something about equality of
1602 // operations. In particular, if the comparison is true/false when the
1603 // operands are equal, and we are on the right edge, we know this operation
1604 // is equal to something.
1605 if ((PBranch->TrueEdge && Predicate == CmpInst::ICMP_EQ) ||
1606 (!PBranch->TrueEdge && Predicate == CmpInst::ICMP_NE)) {
1607 addPredicateUsers(PI, I);
1608 addAdditionalUsers(SwappedOps ? Cmp->getOperand(1) : Cmp->getOperand(0),
1609 I);
1610 return createVariableOrConstant(FirstOp);
1611 }
1612 // Handle the special case of floating point.
1613 if (((PBranch->TrueEdge && Predicate == CmpInst::FCMP_OEQ) ||
1614 (!PBranch->TrueEdge && Predicate == CmpInst::FCMP_UNE)) &&
1615 isa<ConstantFP>(FirstOp) && !cast<ConstantFP>(FirstOp)->isZero()) {
1616 addPredicateUsers(PI, I);
1617 addAdditionalUsers(SwappedOps ? Cmp->getOperand(1) : Cmp->getOperand(0),
1618 I);
1619 return createConstantExpression(cast<Constant>(FirstOp));
1620 }
1621 }
1622 return nullptr;
1623}
1624
1625// Evaluate read only and pure calls, and create an expression result.
1626const Expression *NewGVN::performSymbolicCallEvaluation(Instruction *I) const {
1627 auto *CI = cast<CallInst>(I);
1628 if (auto *II = dyn_cast<IntrinsicInst>(I)) {
1629 // Intrinsics with the returned attribute are copies of arguments.
1630 if (auto *ReturnedValue = II->getReturnedArgOperand()) {
1631 if (II->getIntrinsicID() == Intrinsic::ssa_copy)
1632 if (const auto *Result = performSymbolicPredicateInfoEvaluation(I))
1633 return Result;
1634 return createVariableOrConstant(ReturnedValue);
1635 }
1636 }
1637 if (AA->doesNotAccessMemory(CI)) {
1638 return createCallExpression(CI, TOPClass->getMemoryLeader());
1639 } else if (AA->onlyReadsMemory(CI)) {
1640 MemoryAccess *DefiningAccess = MSSAWalker->getClobberingMemoryAccess(CI);
1641 return createCallExpression(CI, DefiningAccess);
1642 }
1643 return nullptr;
1644}
1645
1646// Retrieve the memory class for a given MemoryAccess.
1647CongruenceClass *NewGVN::getMemoryClass(const MemoryAccess *MA) const {
1648 auto *Result = MemoryAccessToClass.lookup(MA);
1649 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1649, __PRETTY_FUNCTION__))
;
1650 return Result;
1651}
1652
1653// Update the MemoryAccess equivalence table to say that From is equal to To,
1654// and return true if this is different from what already existed in the table.
1655bool NewGVN::setMemoryClass(const MemoryAccess *From,
1656 CongruenceClass *NewClass) {
1657 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1658, __PRETTY_FUNCTION__))
1658 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1658, __PRETTY_FUNCTION__))
;
1659 LLVM_DEBUG(dbgs() << "Setting " << *From)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Setting " << *From; } } while
(false)
;
1660 LLVM_DEBUG(dbgs() << " equivalent to congruence class ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " equivalent to congruence class "
; } } while (false)
;
1661 LLVM_DEBUG(dbgs() << NewClass->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << NewClass->getID() << " with current MemoryAccess leader "
; } } while (false)
1662 << " with current MemoryAccess leader ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << NewClass->getID() << " with current MemoryAccess leader "
; } } while (false)
;
1663 LLVM_DEBUG(dbgs() << *NewClass->getMemoryLeader() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << *NewClass->getMemoryLeader()
<< "\n"; } } while (false)
;
1664
1665 auto LookupResult = MemoryAccessToClass.find(From);
1666 bool Changed = false;
1667 // If it's already in the table, see if the value changed.
1668 if (LookupResult != MemoryAccessToClass.end()) {
1669 auto *OldClass = LookupResult->second;
1670 if (OldClass != NewClass) {
1671 // If this is a phi, we have to handle memory member updates.
1672 if (auto *MP = dyn_cast<MemoryPhi>(From)) {
1673 OldClass->memory_erase(MP);
1674 NewClass->memory_insert(MP);
1675 // This may have killed the class if it had no non-memory members
1676 if (OldClass->getMemoryLeader() == From) {
1677 if (OldClass->definesNoMemory()) {
1678 OldClass->setMemoryLeader(nullptr);
1679 } else {
1680 OldClass->setMemoryLeader(getNextMemoryLeader(OldClass));
1681 LLVM_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)
1682 << 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)
1683 << *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)
1684 << " 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)
1685 << "\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)
;
1686 markMemoryLeaderChangeTouched(OldClass);
1687 }
1688 }
1689 }
1690 // It wasn't equivalent before, and now it is.
1691 LookupResult->second = NewClass;
1692 Changed = true;
1693 }
1694 }
1695
1696 return Changed;
1697}
1698
1699// Determine if a instruction is cycle-free. That means the values in the
1700// instruction don't depend on any expressions that can change value as a result
1701// of the instruction. For example, a non-cycle free instruction would be v =
1702// phi(0, v+1).
1703bool NewGVN::isCycleFree(const Instruction *I) const {
1704 // In order to compute cycle-freeness, we do SCC finding on the instruction,
1705 // and see what kind of SCC it ends up in. If it is a singleton, it is
1706 // cycle-free. If it is not in a singleton, it is only cycle free if the
1707 // other members are all phi nodes (as they do not compute anything, they are
1708 // copies).
1709 auto ICS = InstCycleState.lookup(I);
1710 if (ICS == ICS_Unknown) {
1711 SCCFinder.Start(I);
1712 auto &SCC = SCCFinder.getComponentFor(I);
1713 // It's cycle free if it's size 1 or the SCC is *only* phi nodes.
1714 if (SCC.size() == 1)
1715 InstCycleState.insert({I, ICS_CycleFree});
1716 else {
1717 bool AllPhis = llvm::all_of(SCC, [](const Value *V) {
1718 return isa<PHINode>(V) || isCopyOfAPHI(V);
1719 });
1720 ICS = AllPhis ? ICS_CycleFree : ICS_Cycle;
1721 for (auto *Member : SCC)
1722 if (auto *MemberPhi = dyn_cast<PHINode>(Member))
1723 InstCycleState.insert({MemberPhi, ICS});
1724 }
1725 }
1726 if (ICS == ICS_Cycle)
1727 return false;
1728 return true;
1729}
1730
1731// Evaluate PHI nodes symbolically and create an expression result.
1732const Expression *
1733NewGVN::performSymbolicPHIEvaluation(ArrayRef<ValPair> PHIOps,
1734 Instruction *I,
1735 BasicBlock *PHIBlock) const {
1736 // True if one of the incoming phi edges is a backedge.
1737 bool HasBackedge = false;
1738 // All constant tracks the state of whether all the *original* phi operands
1739 // This is really shorthand for "this phi cannot cycle due to forward
1740 // change in value of the phi is guaranteed not to later change the value of
1741 // the phi. IE it can't be v = phi(undef, v+1)
1742 bool OriginalOpsConstant = true;
1743 auto *E = cast<PHIExpression>(createPHIExpression(
22
Calling 'NewGVN::createPHIExpression'
1744 PHIOps, I, PHIBlock, HasBackedge, OriginalOpsConstant));
1745 // We match the semantics of SimplifyPhiNode from InstructionSimplify here.
1746 // See if all arguments are the same.
1747 // We track if any were undef because they need special handling.
1748 bool HasUndef = false;
1749 auto Filtered = make_filter_range(E->operands(), [&](Value *Arg) {
1750 if (isa<UndefValue>(Arg)) {
1751 HasUndef = true;
1752 return false;
1753 }
1754 return true;
1755 });
1756 // If we are left with no operands, it's dead.
1757 if (empty(Filtered)) {
1758 // If it has undef at this point, it means there are no-non-undef arguments,
1759 // and thus, the value of the phi node must be undef.
1760 if (HasUndef) {
1761 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHI Node " << *I <<
" has no non-undef arguments, valuing it as undef\n"; } } while
(false)
1762 dbgs() << "PHI Node " << *Ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHI Node " << *I <<
" has no non-undef arguments, valuing it as undef\n"; } } while
(false)
1763 << " has no non-undef arguments, valuing it as undef\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHI Node " << *I <<
" has no non-undef arguments, valuing it as undef\n"; } } while
(false)
;
1764 return createConstantExpression(UndefValue::get(I->getType()));
1765 }
1766
1767 LLVM_DEBUG(dbgs() << "No arguments of PHI node " << *I << " are live\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "No arguments of PHI node " <<
*I << " are live\n"; } } while (false)
;
1768 deleteExpression(E);
1769 return createDeadExpression();
1770 }
1771 Value *AllSameValue = *(Filtered.begin());
1772 ++Filtered.begin();
1773 // Can't use std::equal here, sadly, because filter.begin moves.
1774 if (llvm::all_of(Filtered, [&](Value *Arg) { return Arg == AllSameValue; })) {
1775 // In LLVM's non-standard representation of phi nodes, it's possible to have
1776 // phi nodes with cycles (IE dependent on other phis that are .... dependent
1777 // on the original phi node), especially in weird CFG's where some arguments
1778 // are unreachable, or uninitialized along certain paths. This can cause
1779 // infinite loops during evaluation. We work around this by not trying to
1780 // really evaluate them independently, but instead using a variable
1781 // expression to say if one is equivalent to the other.
1782 // We also special case undef, so that if we have an undef, we can't use the
1783 // common value unless it dominates the phi block.
1784 if (HasUndef) {
1785 // If we have undef and at least one other value, this is really a
1786 // multivalued phi, and we need to know if it's cycle free in order to
1787 // evaluate whether we can ignore the undef. The other parts of this are
1788 // just shortcuts. If there is no backedge, or all operands are
1789 // constants, it also must be cycle free.
1790 if (HasBackedge && !OriginalOpsConstant &&
1791 !isa<UndefValue>(AllSameValue) && !isCycleFree(I))
1792 return E;
1793
1794 // Only have to check for instructions
1795 if (auto *AllSameInst = dyn_cast<Instruction>(AllSameValue))
1796 if (!someEquivalentDominates(AllSameInst, I))
1797 return E;
1798 }
1799 // Can't simplify to something that comes later in the iteration.
1800 // Otherwise, when and if it changes congruence class, we will never catch
1801 // up. We will always be a class behind it.
1802 if (isa<Instruction>(AllSameValue) &&
1803 InstrToDFSNum(AllSameValue) > InstrToDFSNum(I))
1804 return E;
1805 NumGVNPhisAllSame++;
1806 LLVM_DEBUG(dbgs() << "Simplified PHI node " << *I << " to " << *AllSameValuedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified PHI node " <<
*I << " to " << *AllSameValue << "\n"; } }
while (false)
1807 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified PHI node " <<
*I << " to " << *AllSameValue << "\n"; } }
while (false)
;
1808 deleteExpression(E);
1809 return createVariableOrConstant(AllSameValue);
1810 }
1811 return E;
1812}
1813
1814const Expression *
1815NewGVN::performSymbolicAggrValueEvaluation(Instruction *I) const {
1816 if (auto *EI = dyn_cast<ExtractValueInst>(I)) {
1817 auto *WO = dyn_cast<WithOverflowInst>(EI->getAggregateOperand());
1818 if (WO && EI->getNumIndices() == 1 && *EI->idx_begin() == 0)
1819 // EI is an extract from one of our with.overflow intrinsics. Synthesize
1820 // a semantically equivalent expression instead of an extract value
1821 // expression.
1822 return createBinaryExpression(WO->getBinaryOp(), EI->getType(),
1823 WO->getLHS(), WO->getRHS(), I);
1824 }
1825
1826 return createAggregateValueExpression(I);
1827}
1828
1829const Expression *NewGVN::performSymbolicCmpEvaluation(Instruction *I) const {
1830 assert(isa<CmpInst>(I) && "Expected a cmp instruction.")((isa<CmpInst>(I) && "Expected a cmp instruction."
) ? static_cast<void> (0) : __assert_fail ("isa<CmpInst>(I) && \"Expected a cmp instruction.\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 1830, __PRETTY_FUNCTION__))
;
1831
1832 auto *CI = cast<CmpInst>(I);
1833 // See if our operands are equal to those of a previous predicate, and if so,
1834 // if it implies true or false.
1835 auto Op0 = lookupOperandLeader(CI->getOperand(0));
1836 auto Op1 = lookupOperandLeader(CI->getOperand(1));
1837 auto OurPredicate = CI->getPredicate();
1838 if (shouldSwapOperands(Op0, Op1)) {
1839 std::swap(Op0, Op1);
1840 OurPredicate = CI->getSwappedPredicate();
1841 }
1842
1843 // Avoid processing the same info twice.
1844 const PredicateBase *LastPredInfo = nullptr;
1845 // See if we know something about the comparison itself, like it is the target
1846 // of an assume.
1847 auto *CmpPI = PredInfo->getPredicateInfoFor(I);
1848 if (dyn_cast_or_null<PredicateAssume>(CmpPI))
1849 return createConstantExpression(ConstantInt::getTrue(CI->getType()));
1850
1851 if (Op0 == Op1) {
1852 // This condition does not depend on predicates, no need to add users
1853 if (CI->isTrueWhenEqual())
1854 return createConstantExpression(ConstantInt::getTrue(CI->getType()));
1855 else if (CI->isFalseWhenEqual())
1856 return createConstantExpression(ConstantInt::getFalse(CI->getType()));
1857 }
1858
1859 // NOTE: Because we are comparing both operands here and below, and using
1860 // previous comparisons, we rely on fact that predicateinfo knows to mark
1861 // comparisons that use renamed operands as users of the earlier comparisons.
1862 // It is *not* enough to just mark predicateinfo renamed operands as users of
1863 // the earlier comparisons, because the *other* operand may have changed in a
1864 // previous iteration.
1865 // Example:
1866 // icmp slt %a, %b
1867 // %b.0 = ssa.copy(%b)
1868 // false branch:
1869 // icmp slt %c, %b.0
1870
1871 // %c and %a may start out equal, and thus, the code below will say the second
1872 // %icmp is false. c may become equal to something else, and in that case the
1873 // %second icmp *must* be reexamined, but would not if only the renamed
1874 // %operands are considered users of the icmp.
1875
1876 // *Currently* we only check one level of comparisons back, and only mark one
1877 // level back as touched when changes happen. If you modify this code to look
1878 // back farther through comparisons, you *must* mark the appropriate
1879 // comparisons as users in PredicateInfo.cpp, or you will cause bugs. See if
1880 // we know something just from the operands themselves
1881
1882 // See if our operands have predicate info, so that we may be able to derive
1883 // something from a previous comparison.
1884 for (const auto &Op : CI->operands()) {
1885 auto *PI = PredInfo->getPredicateInfoFor(Op);
1886 if (const auto *PBranch = dyn_cast_or_null<PredicateBranch>(PI)) {
1887 if (PI == LastPredInfo)
1888 continue;
1889 LastPredInfo = PI;
1890 // In phi of ops cases, we may have predicate info that we are evaluating
1891 // in a different context.
1892 if (!DT->dominates(PBranch->To, getBlockForValue(I)))
1893 continue;
1894 // TODO: Along the false edge, we may know more things too, like
1895 // icmp of
1896 // same operands is false.
1897 // TODO: We only handle actual comparison conditions below, not
1898 // and/or.
1899 auto *BranchCond = dyn_cast<CmpInst>(PBranch->Condition);
1900 if (!BranchCond)
1901 continue;
1902 auto *BranchOp0 = lookupOperandLeader(BranchCond->getOperand(0));
1903 auto *BranchOp1 = lookupOperandLeader(BranchCond->getOperand(1));
1904 auto BranchPredicate = BranchCond->getPredicate();
1905 if (shouldSwapOperands(BranchOp0, BranchOp1)) {
1906 std::swap(BranchOp0, BranchOp1);
1907 BranchPredicate = BranchCond->getSwappedPredicate();
1908 }
1909 if (BranchOp0 == Op0 && BranchOp1 == Op1) {
1910 if (PBranch->TrueEdge) {
1911 // If we know the previous predicate is true and we are in the true
1912 // edge then we may be implied true or false.
1913 if (CmpInst::isImpliedTrueByMatchingCmp(BranchPredicate,
1914 OurPredicate)) {
1915 addPredicateUsers(PI, I);
1916 return createConstantExpression(
1917 ConstantInt::getTrue(CI->getType()));
1918 }
1919
1920 if (CmpInst::isImpliedFalseByMatchingCmp(BranchPredicate,
1921 OurPredicate)) {
1922 addPredicateUsers(PI, I);
1923 return createConstantExpression(
1924 ConstantInt::getFalse(CI->getType()));
1925 }
1926 } else {
1927 // Just handle the ne and eq cases, where if we have the same
1928 // operands, we may know something.
1929 if (BranchPredicate == OurPredicate) {
1930 addPredicateUsers(PI, I);
1931 // Same predicate, same ops,we know it was false, so this is false.
1932 return createConstantExpression(
1933 ConstantInt::getFalse(CI->getType()));
1934 } else if (BranchPredicate ==
1935 CmpInst::getInversePredicate(OurPredicate)) {
1936 addPredicateUsers(PI, I);
1937 // Inverse predicate, we know the other was false, so this is true.
1938 return createConstantExpression(
1939 ConstantInt::getTrue(CI->getType()));
1940 }
1941 }
1942 }
1943 }
1944 }
1945 // Create expression will take care of simplifyCmpInst
1946 return createExpression(I);
1947}
1948
1949// Substitute and symbolize the value before value numbering.
1950const Expression *
1951NewGVN::performSymbolicEvaluation(Value *V,
1952 SmallPtrSetImpl<Value *> &Visited) const {
1953 const Expression *E = nullptr;
1954 if (auto *C = dyn_cast<Constant>(V))
1955 E = createConstantExpression(C);
1956 else if (isa<Argument>(V) || isa<GlobalVariable>(V)) {
1957 E = createVariableExpression(V);
1958 } else {
1959 // TODO: memory intrinsics.
1960 // TODO: Some day, we should do the forward propagation and reassociation
1961 // parts of the algorithm.
1962 auto *I = cast<Instruction>(V);
1963 switch (I->getOpcode()) {
1964 case Instruction::ExtractValue:
1965 case Instruction::InsertValue:
1966 E = performSymbolicAggrValueEvaluation(I);
1967 break;
1968 case Instruction::PHI: {
1969 SmallVector<ValPair, 3> Ops;
1970 auto *PN = cast<PHINode>(I);
1971 for (unsigned i = 0; i < PN->getNumOperands(); ++i)
1972 Ops.push_back({PN->getIncomingValue(i), PN->getIncomingBlock(i)});
1973 // Sort to ensure the invariant createPHIExpression requires is met.
1974 sortPHIOps(Ops);
1975 E = performSymbolicPHIEvaluation(Ops, I, getBlockForValue(I));
1976 } break;
1977 case Instruction::Call:
1978 E = performSymbolicCallEvaluation(I);
1979 break;
1980 case Instruction::Store:
1981 E = performSymbolicStoreEvaluation(I);
1982 break;
1983 case Instruction::Load:
1984 E = performSymbolicLoadEvaluation(I);
1985 break;
1986 case Instruction::BitCast:
1987 E = createExpression(I);
1988 break;
1989 case Instruction::ICmp:
1990 case Instruction::FCmp:
1991 E = performSymbolicCmpEvaluation(I);
1992 break;
1993 case Instruction::Add:
1994 case Instruction::FAdd:
1995 case Instruction::Sub:
1996 case Instruction::FSub:
1997 case Instruction::Mul:
1998 case Instruction::FMul:
1999 case Instruction::UDiv:
2000 case Instruction::SDiv:
2001 case Instruction::FDiv:
2002 case Instruction::URem:
2003 case Instruction::SRem:
2004 case Instruction::FRem:
2005 case Instruction::Shl:
2006 case Instruction::LShr:
2007 case Instruction::AShr:
2008 case Instruction::And:
2009 case Instruction::Or:
2010 case Instruction::Xor:
2011 case Instruction::Trunc:
2012 case Instruction::ZExt:
2013 case Instruction::SExt:
2014 case Instruction::FPToUI:
2015 case Instruction::FPToSI:
2016 case Instruction::UIToFP:
2017 case Instruction::SIToFP:
2018 case Instruction::FPTrunc:
2019 case Instruction::FPExt:
2020 case Instruction::PtrToInt:
2021 case Instruction::IntToPtr:
2022 case Instruction::Select:
2023 case Instruction::ExtractElement:
2024 case Instruction::InsertElement:
2025 case Instruction::ShuffleVector:
2026 case Instruction::GetElementPtr:
2027 E = createExpression(I);
2028 break;
2029 default:
2030 return nullptr;
2031 }
2032 }
2033 return E;
2034}
2035
2036// Look up a container in a map, and then call a function for each thing in the
2037// found container.
2038template <typename Map, typename KeyType, typename Func>
2039void NewGVN::for_each_found(Map &M, const KeyType &Key, Func F) {
2040 const auto Result = M.find_as(Key);
2041 if (Result != M.end())
2042 for (typename Map::mapped_type::value_type Mapped : Result->second)
2043 F(Mapped);
2044}
2045
2046// Look up a container of values/instructions in a map, and touch all the
2047// instructions in the container. Then erase value from the map.
2048template <typename Map, typename KeyType>
2049void NewGVN::touchAndErase(Map &M, const KeyType &Key) {
2050 const auto Result = M.find_as(Key);
2051 if (Result != M.end()) {
2052 for (const typename Map::mapped_type::value_type Mapped : Result->second)
2053 TouchedInstructions.set(InstrToDFSNum(Mapped));
2054 M.erase(Result);
2055 }
2056}
2057
2058void NewGVN::addAdditionalUsers(Value *To, Value *User) const {
2059 assert(User && To != User)((User && To != User) ? static_cast<void> (0) :
__assert_fail ("User && To != User", "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2059, __PRETTY_FUNCTION__))
;
2060 if (isa<Instruction>(To))
2061 AdditionalUsers[To].insert(User);
2062}
2063
2064void NewGVN::markUsersTouched(Value *V) {
2065 // Now mark the users as touched.
2066 for (auto *User : V->users()) {
2067 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?\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2067, __PRETTY_FUNCTION__))
;
2068 TouchedInstructions.set(InstrToDFSNum(User));
2069 }
2070 touchAndErase(AdditionalUsers, V);
2071}
2072
2073void NewGVN::addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) const {
2074 LLVM_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
)
;
2075 MemoryToUsers[To].insert(U);
2076}
2077
2078void NewGVN::markMemoryDefTouched(const MemoryAccess *MA) {
2079 TouchedInstructions.set(MemoryToDFSNum(MA));
2080}
2081
2082void NewGVN::markMemoryUsersTouched(const MemoryAccess *MA) {
2083 if (isa<MemoryUse>(MA))
2084 return;
2085 for (auto U : MA->users())
2086 TouchedInstructions.set(MemoryToDFSNum(U));
2087 touchAndErase(MemoryToUsers, MA);
2088}
2089
2090// Add I to the set of users of a given predicate.
2091void NewGVN::addPredicateUsers(const PredicateBase *PB, Instruction *I) const {
2092 // Don't add temporary instructions to the user lists.
2093 if (AllTempInstructions.count(I))
2094 return;
2095
2096 if (auto *PBranch = dyn_cast<PredicateBranch>(PB))
2097 PredicateToUsers[PBranch->Condition].insert(I);
2098 else if (auto *PAssume = dyn_cast<PredicateBranch>(PB))
2099 PredicateToUsers[PAssume->Condition].insert(I);
2100}
2101
2102// Touch all the predicates that depend on this instruction.
2103void NewGVN::markPredicateUsersTouched(Instruction *I) {
2104 touchAndErase(PredicateToUsers, I);
2105}
2106
2107// Mark users affected by a memory leader change.
2108void NewGVN::markMemoryLeaderChangeTouched(CongruenceClass *CC) {
2109 for (auto M : CC->memory())
2110 markMemoryDefTouched(M);
2111}
2112
2113// Touch the instructions that need to be updated after a congruence class has a
2114// leader change, and mark changed values.
2115void NewGVN::markValueLeaderChangeTouched(CongruenceClass *CC) {
2116 for (auto M : *CC) {
2117 if (auto *I = dyn_cast<Instruction>(M))
2118 TouchedInstructions.set(InstrToDFSNum(I));
2119 LeaderChanges.insert(M);
2120 }
2121}
2122
2123// Give a range of things that have instruction DFS numbers, this will return
2124// the member of the range with the smallest dfs number.
2125template <class T, class Range>
2126T *NewGVN::getMinDFSOfRange(const Range &R) const {
2127 std::pair<T *, unsigned> MinDFS = {nullptr, ~0U};
2128 for (const auto X : R) {
2129 auto DFSNum = InstrToDFSNum(X);
2130 if (DFSNum < MinDFS.second)
2131 MinDFS = {X, DFSNum};
2132 }
2133 return MinDFS.first;
2134}
2135
2136// This function returns the MemoryAccess that should be the next leader of
2137// congruence class CC, under the assumption that the current leader is going to
2138// disappear.
2139const MemoryAccess *NewGVN::getNextMemoryLeader(CongruenceClass *CC) const {
2140 // TODO: If this ends up to slow, we can maintain a next memory leader like we
2141 // do for regular leaders.
2142 // Make sure there will be a leader to find.
2143 assert(!CC->definesNoMemory() && "Can't get next leader if there is none")((!CC->definesNoMemory() && "Can't get next leader if there is none"
) ? static_cast<void> (0) : __assert_fail ("!CC->definesNoMemory() && \"Can't get next leader if there is none\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2143, __PRETTY_FUNCTION__))
;
2144 if (CC->getStoreCount() > 0) {
2145 if (auto *NL = dyn_cast_or_null<StoreInst>(CC->getNextLeader().first))
2146 return getMemoryAccess(NL);
2147 // Find the store with the minimum DFS number.
2148 auto *V = getMinDFSOfRange<Value>(make_filter_range(
2149 *CC, [&](const Value *V) { return isa<StoreInst>(V); }));
2150 return getMemoryAccess(cast<StoreInst>(V));
2151 }
2152 assert(CC->getStoreCount() == 0)((CC->getStoreCount() == 0) ? static_cast<void> (0) :
__assert_fail ("CC->getStoreCount() == 0", "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2152, __PRETTY_FUNCTION__))
;
2153
2154 // Given our assertion, hitting this part must mean
2155 // !OldClass->memory_empty()
2156 if (CC->memory_size() == 1)
2157 return *CC->memory_begin();
2158 return getMinDFSOfRange<const MemoryPhi>(CC->memory());
2159}
2160
2161// This function returns the next value leader of a congruence class, under the
2162// assumption that the current leader is going away. This should end up being
2163// the next most dominating member.
2164Value *NewGVN::getNextValueLeader(CongruenceClass *CC) const {
2165 // We don't need to sort members if there is only 1, and we don't care about
2166 // sorting the TOP class because everything either gets out of it or is
2167 // unreachable.
2168
2169 if (CC->size() == 1 || CC == TOPClass) {
2170 return *(CC->begin());
2171 } else if (CC->getNextLeader().first) {
2172 ++NumGVNAvoidedSortedLeaderChanges;
2173 return CC->getNextLeader().first;
2174 } else {
2175 ++NumGVNSortedLeaderChanges;
2176 // NOTE: If this ends up to slow, we can maintain a dual structure for
2177 // member testing/insertion, or keep things mostly sorted, and sort only
2178 // here, or use SparseBitVector or ....
2179 return getMinDFSOfRange<Value>(*CC);
2180 }
2181}
2182
2183// Move a MemoryAccess, currently in OldClass, to NewClass, including updates to
2184// the memory members, etc for the move.
2185//
2186// The invariants of this function are:
2187//
2188// - I must be moving to NewClass from OldClass
2189// - The StoreCount of OldClass and NewClass is expected to have been updated
2190// for I already if it is a store.
2191// - The OldClass memory leader has not been updated yet if I was the leader.
2192void NewGVN::moveMemoryToNewCongruenceClass(Instruction *I,
2193 MemoryAccess *InstMA,
2194 CongruenceClass *OldClass,
2195 CongruenceClass *NewClass) {
2196 // If the leader is I, and we had a representative MemoryAccess, it should
2197 // be the MemoryAccess of OldClass.
2198 assert((!InstMA || !OldClass->getMemoryLeader() ||(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader
()) == MemoryAccessToClass.lookup(InstMA)) && "Representative MemoryAccess mismatch"
) ? static_cast<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader()) == MemoryAccessToClass.lookup(InstMA)) && \"Representative MemoryAccess mismatch\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2202, __PRETTY_FUNCTION__))
2199 OldClass->getLeader() != I ||(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader
()) == MemoryAccessToClass.lookup(InstMA)) && "Representative MemoryAccess mismatch"
) ? static_cast<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader()) == MemoryAccessToClass.lookup(InstMA)) && \"Representative MemoryAccess mismatch\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2202, __PRETTY_FUNCTION__))
2200 MemoryAccessToClass.lookup(OldClass->getMemoryLeader()) ==(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader
()) == MemoryAccessToClass.lookup(InstMA)) && "Representative MemoryAccess mismatch"
) ? static_cast<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader()) == MemoryAccessToClass.lookup(InstMA)) && \"Representative MemoryAccess mismatch\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2202, __PRETTY_FUNCTION__))
2201 MemoryAccessToClass.lookup(InstMA)) &&(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader
()) == MemoryAccessToClass.lookup(InstMA)) && "Representative MemoryAccess mismatch"
) ? static_cast<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader()) == MemoryAccessToClass.lookup(InstMA)) && \"Representative MemoryAccess mismatch\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2202, __PRETTY_FUNCTION__))
2202 "Representative MemoryAccess mismatch")(((!InstMA || !OldClass->getMemoryLeader() || OldClass->
getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader
()) == MemoryAccessToClass.lookup(InstMA)) && "Representative MemoryAccess mismatch"
) ? static_cast<void> (0) : __assert_fail ("(!InstMA || !OldClass->getMemoryLeader() || OldClass->getLeader() != I || MemoryAccessToClass.lookup(OldClass->getMemoryLeader()) == MemoryAccessToClass.lookup(InstMA)) && \"Representative MemoryAccess mismatch\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2202, __PRETTY_FUNCTION__))
;
2203 // First, see what happens to the new class
2204 if (!NewClass->getMemoryLeader()) {
2205 // Should be a new class, or a store becoming a leader of a new class.
2206 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)"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2207, __PRETTY_FUNCTION__))
2207 (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)"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2207, __PRETTY_FUNCTION__))
;
2208 NewClass->setMemoryLeader(InstMA);
2209 // Mark it touched if we didn't just create a singleton
2210 LLVM_DEBUG(dbgs() << "Memory class leader change for class "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)
2211 << 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)
2212 << " 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)
;
2213 markMemoryLeaderChangeTouched(NewClass);
2214 }
2215 setMemoryClass(InstMA, NewClass);
2216 // Now, fixup the old class if necessary
2217 if (OldClass->getMemoryLeader() == InstMA) {
2218 if (!OldClass->definesNoMemory()) {
2219 OldClass->setMemoryLeader(getNextMemoryLeader(OldClass));
2220 LLVM_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)
2221 << 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)
2222 << *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)
2223 << " 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)
;
2224 markMemoryLeaderChangeTouched(OldClass);
2225 } else
2226 OldClass->setMemoryLeader(nullptr);
2227 }
2228}
2229
2230// Move a value, currently in OldClass, to be part of NewClass
2231// Update OldClass and NewClass for the move (including changing leaders, etc).
2232void NewGVN::moveValueToNewCongruenceClass(Instruction *I, const Expression *E,
2233 CongruenceClass *OldClass,
2234 CongruenceClass *NewClass) {
2235 if (I == OldClass->getNextLeader().first)
2236 OldClass->resetNextLeader();
2237
2238 OldClass->erase(I);
2239 NewClass->insert(I);
2240
2241 if (NewClass->getLeader() != I)
2242 NewClass->addPossibleNextLeader({I, InstrToDFSNum(I)});
2243 // Handle our special casing of stores.
2244 if (auto *SI = dyn_cast<StoreInst>(I)) {
2245 OldClass->decStoreCount();
2246 // Okay, so when do we want to make a store a leader of a class?
2247 // If we have a store defined by an earlier load, we want the earlier load
2248 // to lead the class.
2249 // If we have a store defined by something else, we want the store to lead
2250 // the class so everything else gets the "something else" as a value.
2251 // If we have a store as the single member of the class, we want the store
2252 // as the leader
2253 if (NewClass->getStoreCount() == 0 && !NewClass->getStoredValue()) {
2254 // If it's a store expression we are using, it means we are not equivalent
2255 // to something earlier.
2256 if (auto *SE = dyn_cast<StoreExpression>(E)) {
2257 NewClass->setStoredValue(SE->getStoredValue());
2258 markValueLeaderChangeTouched(NewClass);
2259 // Shift the new class leader to be the store
2260 LLVM_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)
2261 << NewClass->getID() << " from "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)
2262 << *NewClass->getLeader() << " to " << *SIdo { 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)
2263 << " 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)
;
2264 // If we changed the leader, we have to mark it changed because we don't
2265 // know what it will do to symbolic evaluation.
2266 NewClass->setLeader(SI);
2267 }
2268 // We rely on the code below handling the MemoryAccess change.
2269 }
2270 NewClass->incStoreCount();
2271 }
2272 // True if there is no memory instructions left in a class that had memory
2273 // instructions before.
2274
2275 // If it's not a memory use, set the MemoryAccess equivalence
2276 auto *InstMA = dyn_cast_or_null<MemoryDef>(getMemoryAccess(I));
2277 if (InstMA)
2278 moveMemoryToNewCongruenceClass(I, InstMA, OldClass, NewClass);
2279 ValueToClass[I] = NewClass;
2280 // See if we destroyed the class or need to swap leaders.
2281 if (OldClass->empty() && OldClass != TOPClass) {
2282 if (OldClass->getDefiningExpr()) {
2283 LLVM_DEBUG(dbgs() << "Erasing expression " << *OldClass->getDefiningExpr()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Erasing expression " << *
OldClass->getDefiningExpr() << " from table\n"; } } while
(false)
2284 << " from table\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Erasing expression " << *
OldClass->getDefiningExpr() << " from table\n"; } } while
(false)
;
2285 // We erase it as an exact expression to make sure we don't just erase an
2286 // equivalent one.
2287 auto Iter = ExpressionToClass.find_as(
2288 ExactEqualsExpression(*OldClass->getDefiningExpr()));
2289 if (Iter != ExpressionToClass.end())
2290 ExpressionToClass.erase(Iter);
2291#ifdef EXPENSIVE_CHECKS
2292 assert((((*OldClass->getDefiningExpr() != *E || ExpressionToClass
.lookup(E)) && "We erased the expression we just inserted, which should not happen"
) ? static_cast<void> (0) : __assert_fail ("(*OldClass->getDefiningExpr() != *E || ExpressionToClass.lookup(E)) && \"We erased the expression we just inserted, which should not happen\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2294, __PRETTY_FUNCTION__))
2293 (*OldClass->getDefiningExpr() != *E || ExpressionToClass.lookup(E)) &&(((*OldClass->getDefiningExpr() != *E || ExpressionToClass
.lookup(E)) && "We erased the expression we just inserted, which should not happen"
) ? static_cast<void> (0) : __assert_fail ("(*OldClass->getDefiningExpr() != *E || ExpressionToClass.lookup(E)) && \"We erased the expression we just inserted, which should not happen\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2294, __PRETTY_FUNCTION__))
2294 "We erased the expression we just inserted, which should not happen")(((*OldClass->getDefiningExpr() != *E || ExpressionToClass
.lookup(E)) && "We erased the expression we just inserted, which should not happen"
) ? static_cast<void> (0) : __assert_fail ("(*OldClass->getDefiningExpr() != *E || ExpressionToClass.lookup(E)) && \"We erased the expression we just inserted, which should not happen\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2294, __PRETTY_FUNCTION__))
;
2295#endif
2296 }
2297 } else if (OldClass->getLeader() == I) {
2298 // When the leader changes, the value numbering of
2299 // everything may change due to symbolization changes, so we need to
2300 // reprocess.
2301 LLVM_DEBUG(dbgs() << "Value class leader change for class "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Value class leader change for class "
<< OldClass->getID() << "\n"; } } while (false
)
2302 << OldClass->getID() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Value class leader change for class "
<< OldClass->getID() << "\n"; } } while (false
)
;
2303 ++NumGVNLeaderChanges;
2304 // Destroy the stored value if there are no more stores to represent it.
2305 // Note that this is basically clean up for the expression removal that
2306 // happens below. If we remove stores from a class, we may leave it as a
2307 // class of equivalent memory phis.
2308 if (OldClass->getStoreCount() == 0) {
2309 if (OldClass->getStoredValue())
2310 OldClass->setStoredValue(nullptr);
2311 }
2312 OldClass->setLeader(getNextValueLeader(OldClass));
2313 OldClass->resetNextLeader();
2314 markValueLeaderChangeTouched(OldClass);
2315 }
2316}
2317
2318// For a given expression, mark the phi of ops instructions that could have
2319// changed as a result.
2320void NewGVN::markPhiOfOpsChanged(const Expression *E) {
2321 touchAndErase(ExpressionToPhiOfOps, E);
2322}
2323
2324// Perform congruence finding on a given value numbering expression.
2325void NewGVN::performCongruenceFinding(Instruction *I, const Expression *E) {
2326 // This is guaranteed to return something, since it will at least find
2327 // TOP.
2328
2329 CongruenceClass *IClass = ValueToClass.lookup(I);
2330 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2330, __PRETTY_FUNCTION__))
;
2331 // Dead classes should have been eliminated from the mapping.
2332 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2332, __PRETTY_FUNCTION__))
;
2333
2334 CongruenceClass *EClass = nullptr;
2335 if (const auto *VE = dyn_cast<VariableExpression>(E)) {
2336 EClass = ValueToClass.lookup(VE->getVariableValue());
2337 } else if (isa<DeadExpression>(E)) {
2338 EClass = TOPClass;
2339 }
2340 if (!EClass) {
2341 auto lookupResult = ExpressionToClass.insert({E, nullptr});
2342
2343 // If it's not in the value table, create a new congruence class.
2344 if (lookupResult.second) {
2345 CongruenceClass *NewClass = createCongruenceClass(nullptr, E);
2346 auto place = lookupResult.first;
2347 place->second = NewClass;
2348
2349 // Constants and variables should always be made the leader.
2350 if (const auto *CE = dyn_cast<ConstantExpression>(E)) {
2351 NewClass->setLeader(CE->getConstantValue());
2352 } else if (const auto *SE = dyn_cast<StoreExpression>(E)) {
2353 StoreInst *SI = SE->getStoreInst();
2354 NewClass->setLeader(SI);
2355 NewClass->setStoredValue(SE->getStoredValue());
2356 // The RepMemoryAccess field will be filled in properly by the
2357 // moveValueToNewCongruenceClass call.
2358 } else {
2359 NewClass->setLeader(I);
2360 }
2361 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2362, __PRETTY_FUNCTION__))
2362 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2362, __PRETTY_FUNCTION__))
;
2363
2364 EClass = NewClass;
2365 LLVM_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)
2366 << " using expression " << *E << " at "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)
2367 << NewClass->getID() << " and leader "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)
2368 << *(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)
;
2369 if (NewClass->getStoredValue())
2370 LLVM_DEBUG(dbgs() << " and stored value "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " and stored value " << *
(NewClass->getStoredValue()); } } while (false)
2371 << *(NewClass->getStoredValue()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " and stored value " << *
(NewClass->getStoredValue()); } } while (false)
;
2372 LLVM_DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "\n"; } } while (false)
;
2373 } else {
2374 EClass = lookupResult.first->second;
2375 if (isa<ConstantExpression>(E))
2376 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2380, __PRETTY_FUNCTION__))
2377 (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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2380, __PRETTY_FUNCTION__))
2378 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2380, __PRETTY_FUNCTION__))
2379 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2380, __PRETTY_FUNCTION__))
2380 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2380, __PRETTY_FUNCTION__))
;
2381
2382 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2382, __PRETTY_FUNCTION__))
;
2383
2384 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 2384, __PRETTY_FUNCTION__))
;
2385 }
2386 }
2387 bool ClassChanged = IClass != EClass;
2388 bool LeaderChanged = LeaderChanges.erase(I);
2389 if (ClassChanged || LeaderChanged) {
2390 LLVM_DEBUG(dbgs() << "New class " << EClass->getID() << " for expression "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "New class " << EClass->
getID() << " for expression " << *E << "\n"
; } } while (false)
2391 << *E << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "New class " << EClass->
getID() << " for expression " << *E << "\n"
; } } while (false)
;
2392 if (ClassChanged) {
2393 moveValueToNewCongruenceClass(I, E, IClass, EClass);
2394 markPhiOfOpsChanged(E);
2395 }
2396
2397 markUsersTouched(I);
2398 if (MemoryAccess *MA = getMemoryAccess(I))
2399 markMemoryUsersTouched(MA);
2400 if (auto *CI = dyn_cast<CmpInst>(I))
2401 markPredicateUsersTouched(CI);
2402 }
2403 // If we changed the class of the store, we want to ensure nothing finds the
2404 // old store expression. In particular, loads do not compare against stored
2405 // value, so they will find old store expressions (and associated class
2406 // mappings) if we leave them in the table.
2407 if (ClassChanged && isa<StoreInst>(I)) {
2408 auto *OldE = ValueToExpression.lookup(I);
2409 // It could just be that the old class died. We don't want to erase it if we
2410 // just moved classes.
2411 if (OldE && isa<StoreExpression>(OldE) && *E != *OldE) {
2412 // Erase this as an exact expression to ensure we don't erase expressions
2413 // equivalent to it.
2414 auto Iter = ExpressionToClass.find_as(ExactEqualsExpression(*OldE));
2415 if (Iter != ExpressionToClass.end())
2416 ExpressionToClass.erase(Iter);
2417 }
2418 }
2419 ValueToExpression[I] = E;
2420}
2421
2422// Process the fact that Edge (from, to) is reachable, including marking
2423// any newly reachable blocks and instructions for processing.
2424void NewGVN::updateReachableEdge(BasicBlock *From, BasicBlock *To) {
2425 // Check if the Edge was reachable before.
2426 if (ReachableEdges.insert({From, To}).second) {
2427 // If this block wasn't reachable before, all instructions are touched.
2428 if (ReachableBlocks.insert(To).second) {
2429 LLVM_DEBUG(dbgs() << "Block " << getBlockName(To)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " marked reachable\n"; } } while (false)
2430 << " marked reachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " marked reachable\n"; } } while (false)
;
2431 const auto &InstRange = BlockInstRange.lookup(To);
2432 TouchedInstructions.set(InstRange.first, InstRange.second);
2433 } else {
2434 LLVM_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)
2435 << " was reachable, but new edge {"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)
2436 << getBlockName(From) << "," << 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)
2437 << "} 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)
;
2438
2439 // We've made an edge reachable to an existing block, which may
2440 // impact predicates. Otherwise, only mark the phi nodes as touched, as
2441 // they are the only thing that depend on new edges. Anything using their
2442 // values will get propagated to if necessary.
2443 if (MemoryAccess *MemPhi = getMemoryAccess(To))
2444 TouchedInstructions.set(InstrToDFSNum(MemPhi));
2445
2446 // FIXME: We should just add a union op on a Bitvector and
2447 // SparseBitVector. We can do it word by word faster than we are doing it
2448 // here.
2449 for (auto InstNum : RevisitOnReachabilityChange[To])
2450 TouchedInstructions.set(InstNum);
2451 }
2452 }
2453}
2454
2455// Given a predicate condition (from a switch, cmp, or whatever) and a block,
2456// see if we know some constant value for it already.
2457Value *NewGVN::findConditionEquivalence(Value *Cond) const {
2458 auto Result = lookupOperandLeader(Cond);
2459 return isa<Constant>(Result) ? Result : nullptr;
2460}
2461
2462// Process the outgoing edges of a block for reachability.
2463void NewGVN::processOutgoingEdges(Instruction *TI, BasicBlock *B) {
2464 // Evaluate reachability of terminator instruction.
2465 BranchInst *BR;
2466 if ((BR = dyn_cast<BranchInst>(TI)) && BR->isConditional()) {
2467 Value *Cond = BR->getCondition();
2468 Value *CondEvaluated = findConditionEquivalence(Cond);
2469 if (!CondEvaluated) {
2470 if (auto *I = dyn_cast<Instruction>(Cond)) {
2471 const Expression *E = createExpression(I);
2472 if (const auto *CE = dyn_cast<ConstantExpression>(E)) {
2473 CondEvaluated = CE->getConstantValue();
2474 }
2475 } else if (isa<ConstantInt>(Cond)) {
2476 CondEvaluated = Cond;
2477 }
2478 }
2479 ConstantInt *CI;
2480 BasicBlock *TrueSucc = BR->getSuccessor(0);
2481 BasicBlock *FalseSucc = BR->getSuccessor(1);
2482 if (CondEvaluated && (CI = dyn_cast<ConstantInt>(CondEvaluated))) {
2483 if (CI->isOne()) {
2484 LLVM_DEBUG(dbgs() << "Condition for Terminator " << *TIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to true\n"; } } while (false)
2485 << " evaluated to true\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to true\n"; } } while (false)
;
2486 updateReachableEdge(B, TrueSucc);
2487 } else if (CI->isZero()) {
2488 LLVM_DEBUG(dbgs() << "Condition for Terminator " << *TIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to false\n"; } } while (false)
2489 << " evaluated to false\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to false\n"; } } while (false)
;
2490 updateReachableEdge(B, FalseSucc);
2491 }
2492 } else {
2493 updateReachableEdge(B, TrueSucc);
2494 updateReachableEdge(B, FalseSucc);
2495 }
2496 } else if (auto *SI = dyn_cast<SwitchInst>(TI)) {
2497 // For switches, propagate the case values into the case
2498 // destinations.
2499
2500 // Remember how many outgoing edges there are to every successor.
2501 SmallDenseMap<BasicBlock *, unsigned, 16> SwitchEdges;
2502
2503 Value *SwitchCond = SI->getCondition();
2504 Value *CondEvaluated = findConditionEquivalence(SwitchCond);
2505 // See if we were able to turn this switch statement into a constant.
2506 if (CondEvaluated && isa<ConstantInt>(CondEvaluated)) {
2507 auto *CondVal = cast<ConstantInt>(CondEvaluated);
2508 // We should be able to get case value for this.
2509 auto Case = *SI->findCaseValue(CondVal);
2510 if (Case.getCaseSuccessor() == SI->getDefaultDest()) {
2511 // We proved the value is outside of the range of the case.
2512 // We can't do anything other than mark the default dest as reachable,
2513 // and go home.
2514 updateReachableEdge(B, SI->getDefaultDest());
2515 return;
2516 }
2517 // Now get where it goes and mark it reachable.
2518 BasicBlock *TargetBlock = Case.getCaseSuccessor();
2519 updateReachableEdge(B, TargetBlock);
2520 } else {
2521 for (unsigned i = 0, e = SI->getNumSuccessors(); i != e; ++i) {
2522 BasicBlock *TargetBlock = SI->getSuccessor(i);
2523 ++SwitchEdges[TargetBlock];
2524 updateReachableEdge(B, TargetBlock);
2525 }
2526 }
2527 } else {
2528 // Otherwise this is either unconditional, or a type we have no
2529 // idea about. Just mark successors as reachable.
2530 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
2531 BasicBlock *TargetBlock = TI->getSuccessor(i);
2532 updateReachableEdge(B, TargetBlock);
2533 }
2534
2535 // This also may be a memory defining terminator, in which case, set it
2536 // equivalent only to itself.
2537 //
2538 auto *MA = getMemoryAccess(TI);
2539 if (MA && !isa<MemoryUse>(MA)) {
2540 auto *CC = ensureLeaderOfMemoryClass(MA);
2541 if (setMemoryClass(MA, CC))
2542 markMemoryUsersTouched(MA);
2543 }
2544 }
2545}
2546
2547// Remove the PHI of Ops PHI for I
2548void NewGVN::removePhiOfOps(Instruction *I, PHINode *PHITemp) {
2549 InstrDFS.erase(PHITemp);
2550 // It's still a temp instruction. We keep it in the array so it gets erased.
2551 // However, it's no longer used by I, or in the block
2552 TempToBlock.erase(PHITemp);
2553 RealToTemp.erase(I);
2554 // We don't remove the users from the phi node uses. This wastes a little
2555 // time, but such is life. We could use two sets to track which were there
2556 // are the start of NewGVN, and which were added, but right nowt he cost of
2557 // tracking is more than the cost of checking for more phi of ops.
2558}
2559
2560// Add PHI Op in BB as a PHI of operations version of ExistingValue.
2561void NewGVN::addPhiOfOps(PHINode *Op, BasicBlock *BB,
2562 Instruction *ExistingValue) {
2563 InstrDFS[Op] = InstrToDFSNum(ExistingValue);
2564 AllTempInstructions.insert(Op);
2565 TempToBlock[Op] = BB;
2566 RealToTemp[ExistingValue] = Op;
2567 // Add all users to phi node use, as they are now uses of the phi of ops phis
2568 // and may themselves be phi of ops.
2569 for (auto *U : ExistingValue->users())
2570 if (auto *UI = dyn_cast<Instruction>(U))
2571 PHINodeUses.insert(UI);
2572}
2573
2574static bool okayForPHIOfOps(const Instruction *I) {
2575 if (!EnablePhiOfOps)
2576 return false;
2577 return isa<BinaryOperator>(I) || isa<SelectInst>(I) || isa<CmpInst>(I) ||
2578 isa<LoadInst>(I);
2579}
2580
2581bool NewGVN::OpIsSafeForPHIOfOpsHelper(
2582 Value *V, const BasicBlock *PHIBlock,
2583 SmallPtrSetImpl<const Value *> &Visited,
2584 SmallVectorImpl<Instruction *> &Worklist) {
2585
2586 if (!isa<Instruction>(V))
2587 return true;
2588 auto OISIt = OpSafeForPHIOfOps.find(V);
2589 if (OISIt != OpSafeForPHIOfOps.end())
2590 return OISIt->second;
2591
2592 // Keep walking until we either dominate the phi block, or hit a phi, or run
2593 // out of things to check.
2594 if (DT->properlyDominates(getBlockForValue(V), PHIBlock)) {
2595 OpSafeForPHIOfOps.insert({V, true});
2596 return true;
2597 }
2598 // PHI in the same block.
2599 if (isa<PHINode>(V) && getBlockForValue(V) == PHIBlock) {
2600 OpSafeForPHIOfOps.insert({V, false});
2601 return false;
2602 }
2603
2604 auto *OrigI = cast<Instruction>(V);
2605 for (auto *Op : OrigI->operand_values()) {
2606 if (!isa<Instruction>(Op))
2607 continue;
2608 // Stop now if we find an unsafe operand.
2609 auto OISIt = OpSafeForPHIOfOps.find(OrigI);
2610 if (OISIt != OpSafeForPHIOfOps.end()) {
2611 if (!OISIt->second) {
2612 OpSafeForPHIOfOps.insert({V, false});
2613 return false;
2614 }
2615 continue;
2616 }
2617 if (!Visited.insert(Op).second)
2618 continue;
2619 Worklist.push_back(cast<Instruction>(Op));
2620 }
2621 return true;
2622}
2623
2624// Return true if this operand will be safe to use for phi of ops.
2625//
2626// The reason some operands are unsafe is that we are not trying to recursively
2627// translate everything back through phi nodes. We actually expect some lookups
2628// of expressions to fail. In particular, a lookup where the expression cannot
2629// exist in the predecessor. This is true even if the expression, as shown, can
2630// be determined to be constant.
2631bool NewGVN::OpIsSafeForPHIOfOps(Value *V, const BasicBlock *PHIBlock,
2632 SmallPtrSetImpl<const Value *> &Visited) {
2633 SmallVector<Instruction *, 4> Worklist;
2634 if (!OpIsSafeForPHIOfOpsHelper(V, PHIBlock, Visited, Worklist))
2635 return false;
2636 while (!Worklist.empty()) {
2637 auto *I = Worklist.pop_back_val();
2638 if (!OpIsSafeForPHIOfOpsHelper(I, PHIBlock, Visited, Worklist))
2639 return false;
2640 }
2641 OpSafeForPHIOfOps.insert({V, true});
2642 return true;
2643}
2644
2645// Try to find a leader for instruction TransInst, which is a phi translated
2646// version of something in our original program. Visited is used to ensure we
2647// don't infinite loop during translations of cycles. OrigInst is the
2648// instruction in the original program, and PredBB is the predecessor we
2649// translated it through.
2650Value *NewGVN::findLeaderForInst(Instruction *TransInst,
2651 SmallPtrSetImpl<Value *> &Visited,
2652 MemoryAccess *MemAccess, Instruction *OrigInst,
2653 BasicBlock *PredBB) {
2654 unsigned IDFSNum = InstrToDFSNum(OrigInst);
2655 // Make sure it's marked as a temporary instruction.
2656 AllTempInstructions.insert(TransInst);
2657 // and make sure anything that tries to add it's DFS number is
2658 // redirected to the instruction we are making a phi of ops
2659 // for.
2660 TempToBlock.insert({TransInst, PredBB});
2661 InstrDFS.insert({TransInst, IDFSNum});
2662
2663 const Expression *E = performSymbolicEvaluation(TransInst, Visited);
2664 InstrDFS.erase(TransInst);
2665 AllTempInstructions.erase(TransInst);
2666 TempToBlock.erase(TransInst);
2667 if (MemAccess)
2668 TempToMemory.erase(TransInst);
2669 if (!E)
2670 return nullptr;
2671 auto *FoundVal = findPHIOfOpsLeader(E, OrigInst, PredBB);
2672 if (!FoundVal) {
2673 ExpressionToPhiOfOps[E].insert(OrigInst);
2674 LLVM_DEBUG(dbgs() << "Cannot find phi of ops operand for " << *TransInstdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Cannot find phi of ops operand for "
<< *TransInst << " in block " << getBlockName
(PredBB) << "\n"; } } while (false)
2675 << " in block " << getBlockName(PredBB) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Cannot find phi of ops operand for "
<< *TransInst << " in block " << getBlockName
(PredBB) << "\n"; } } while (false)
;
2676 return nullptr;
2677 }
2678 if (auto *SI = dyn_cast<StoreInst>(FoundVal))
2679 FoundVal = SI->getValueOperand();
2680 return FoundVal;
2681}
2682
2683// When we see an instruction that is an op of phis, generate the equivalent phi
2684// of ops form.
2685const Expression *
2686NewGVN::makePossiblePHIOfOps(Instruction *I,
2687 SmallPtrSetImpl<Value *> &Visited) {
2688 if (!okayForPHIOfOps(I))
1
Taking false branch
2689 return nullptr;
2690
2691 if (!Visited.insert(I).second)
2
Assuming the condition is false
3
Taking false branch
2692 return nullptr;
2693 // For now, we require the instruction be cycle free because we don't
2694 // *always* create a phi of ops for instructions that could be done as phi
2695 // of ops, we only do it if we think it is useful. If we did do it all the
2696 // time, we could remove the cycle free check.
2697 if (!isCycleFree(I))
4
Taking false branch
2698 return nullptr;
2699
2700 SmallPtrSet<const Value *, 8> ProcessedPHIs;
2701 // TODO: We don't do phi translation on memory accesses because it's
2702 // complicated. For a load, we'd need to be able to simulate a new memoryuse,
2703 // which we don't have a good way of doing ATM.
2704 auto *MemAccess = getMemoryAccess(I);
2705 // If the memory operation is defined by a memory operation this block that
2706 // isn't a MemoryPhi, transforming the pointer backwards through a scalar phi
2707 // can't help, as it would still be killed by that memory operation.
2708 if (MemAccess && !isa<MemoryPhi>(MemAccess->getDefiningAccess()) &&
5
Assuming the condition is false
6
Taking false branch
2709 MemAccess->getDefiningAccess()->getBlock() == I->getParent())
2710 return nullptr;
2711
2712 // Convert op of phis to phi of ops
2713 SmallPtrSet<const Value *, 10> VisitedOps;
2714 SmallVector<Value *, 4> Ops(I->operand_values());
2715 BasicBlock *SamePHIBlock = nullptr;
2716 PHINode *OpPHI = nullptr;
2717 if (!DebugCounter::shouldExecute(PHIOfOpsCounter))
7
Assuming the condition is false
8
Taking false branch
2718 return nullptr;
2719 for (auto *Op : Ops) {
9
Assuming '__begin1' is not equal to '__end1'
2720 if (!isa<PHINode>(Op)) {
10
Taking true branch
2721 auto *ValuePHI = RealToTemp.lookup(Op);
2722 if (!ValuePHI)
11
Assuming 'ValuePHI' is non-null
12
Taking false branch
2723 continue;
2724 LLVM_DEBUG(dbgs() << "Found possible dependent phi of ops\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found possible dependent phi of ops\n"
; } } while (false)
;
13
Assuming 'DebugFlag' is 0
14
Loop condition is false. Exiting loop
2725 Op = ValuePHI;
2726 }
2727 OpPHI = cast<PHINode>(Op);
2728 if (!SamePHIBlock) {
15
Taking true branch
2729 SamePHIBlock = getBlockForValue(OpPHI);
2730 } else if (SamePHIBlock != getBlockForValue(OpPHI)) {
2731 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHIs for operands are not all in the same block, aborting\n"
; } } while (false)
2732 dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHIs for operands are not all in the same block, aborting\n"
; } } while (false)
2733 << "PHIs for operands are not all in the same block, aborting\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHIs for operands are not all in the same block, aborting\n"
; } } while (false)
;
2734 return nullptr;
2735 }
2736 // No point in doing this for one-operand phis.
2737 if (OpPHI->getNumOperands() == 1) {
16
Assuming the condition is false
17
Taking false branch
2738 OpPHI = nullptr;
2739 continue;
2740 }
2741 }
2742
2743 if (!OpPHI)
18
Taking false branch
2744 return nullptr;
2745
2746 SmallVector<ValPair, 4> PHIOps;
2747 SmallPtrSet<Value *, 4> Deps;
2748 auto *PHIBlock = getBlockForValue(OpPHI);
2749 RevisitOnReachabilityChange[PHIBlock].reset(InstrToDFSNum(I));
2750 for (unsigned PredNum = 0; PredNum < OpPHI->getNumOperands(); ++PredNum) {
19
Assuming the condition is false
20
Loop condition is false. Execution continues on line 2812
2751 auto *PredBB = OpPHI->getIncomingBlock(PredNum);
2752 Value *FoundVal = nullptr;
2753 SmallPtrSet<Value *, 4> CurrentDeps;
2754 // We could just skip unreachable edges entirely but it's tricky to do
2755 // with rewriting existing phi nodes.
2756 if (ReachableEdges.count({PredBB, PHIBlock})) {
2757 // Clone the instruction, create an expression from it that is
2758 // translated back into the predecessor, and see if we have a leader.
2759 Instruction *ValueOp = I->clone();
2760 if (MemAccess)
2761 TempToMemory.insert({ValueOp, MemAccess});
2762 bool SafeForPHIOfOps = true;
2763 VisitedOps.clear();
2764 for (auto &Op : ValueOp->operands()) {
2765 auto *OrigOp = &*Op;
2766 // When these operand changes, it could change whether there is a
2767 // leader for us or not, so we have to add additional users.
2768 if (isa<PHINode>(Op)) {
2769 Op = Op->DoPHITranslation(PHIBlock, PredBB);
2770 if (Op != OrigOp && Op != I)
2771 CurrentDeps.insert(Op);
2772 } else if (auto *ValuePHI = RealToTemp.lookup(Op)) {
2773 if (getBlockForValue(ValuePHI) == PHIBlock)
2774 Op = ValuePHI->getIncomingValueForBlock(PredBB);
2775 }
2776 // If we phi-translated the op, it must be safe.
2777 SafeForPHIOfOps =
2778 SafeForPHIOfOps &&
2779 (Op != OrigOp || OpIsSafeForPHIOfOps(Op, PHIBlock, VisitedOps));
2780 }
2781 // FIXME: For those things that are not safe we could generate
2782 // expressions all the way down, and see if this comes out to a
2783 // constant. For anything where that is true, and unsafe, we should
2784 // have made a phi-of-ops (or value numbered it equivalent to something)
2785 // for the pieces already.
2786 FoundVal = !SafeForPHIOfOps ? nullptr
2787 : findLeaderForInst(ValueOp, Visited,
2788 MemAccess, I, PredBB);
2789 ValueOp->deleteValue();
2790 if (!FoundVal) {
2791 // We failed to find a leader for the current ValueOp, but this might
2792 // change in case of the translated operands change.
2793 if (SafeForPHIOfOps)
2794 for (auto Dep : CurrentDeps)
2795 addAdditionalUsers(Dep, I);
2796
2797 return nullptr;
2798 }
2799 Deps.insert(CurrentDeps.begin(), CurrentDeps.end());
2800 } else {
2801 LLVM_DEBUG(dbgs() << "Skipping phi of ops operand for incoming block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping phi of ops operand for incoming block "
<< getBlockName(PredBB) << " because the block is unreachable\n"
; } } while (false)
2802 << getBlockName(PredBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping phi of ops operand for incoming block "
<< getBlockName(PredBB) << " because the block is unreachable\n"
; } } while (false)
2803 << " because the block is unreachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping phi of ops operand for incoming block "
<< getBlockName(PredBB) << " because the block is unreachable\n"
; } } while (false)
;
2804 FoundVal = UndefValue::get(I->getType());
2805 RevisitOnReachabilityChange[PHIBlock].set(InstrToDFSNum(I));
2806 }
2807
2808 PHIOps.push_back({FoundVal, PredBB});
2809 LLVM_DEBUG(dbgs() << "Found phi of ops operand " << *FoundVal << " in "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found phi of ops operand " <<
*FoundVal << " in " << getBlockName(PredBB) <<
"\n"; } } while (false)
2810 << getBlockName(PredBB) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found phi of ops operand " <<
*FoundVal << " in " << getBlockName(PredBB) <<
"\n"; } } while (false)
;
2811 }
2812 for (auto Dep : Deps)
2813 addAdditionalUsers(Dep, I);
2814 sortPHIOps(PHIOps);
2815 auto *E = performSymbolicPHIEvaluation(PHIOps, I, PHIBlock);
21
Calling 'NewGVN::performSymbolicPHIEvaluation'
2816 if (isa<ConstantExpression>(E) || isa<VariableExpression>(E)) {
2817 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Not creating real PHI of ops because it simplified to existing "
"value or constant\n"; } } while (false)
2818 dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Not creating real PHI of ops because it simplified to existing "
"value or constant\n"; } } while (false)
2819 << "Not creating real PHI of ops because it simplified to existing "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Not creating real PHI of ops because it simplified to existing "
"value or constant\n"; } } while (false)
2820 "value or constant\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Not creating real PHI of ops because it simplified to existing "
"value or constant\n"; } } while (false)
;
2821 return E;
2822 }
2823 auto *ValuePHI = RealToTemp.lookup(I);
2824 bool NewPHI = false;
2825 if (!ValuePHI) {
2826 ValuePHI =
2827 PHINode::Create(I->getType(), OpPHI->getNumOperands(), "phiofops");
2828 addPhiOfOps(ValuePHI, PHIBlock, I);
2829 NewPHI = true;
2830 NumGVNPHIOfOpsCreated++;
2831 }
2832 if (NewPHI) {
2833 for (auto PHIOp : PHIOps)
2834 ValuePHI->addIncoming(PHIOp.first, PHIOp.second);
2835 } else {
2836 TempToBlock[ValuePHI] = PHIBlock;
2837 unsigned int i = 0;
2838 for (auto PHIOp : PHIOps) {
2839 ValuePHI->setIncomingValue(i, PHIOp.first);
2840 ValuePHI->setIncomingBlock(i, PHIOp.second);
2841 ++i;
2842 }
2843 }
2844 RevisitOnReachabilityChange[PHIBlock].set(InstrToDFSNum(I));
2845 LLVM_DEBUG(dbgs() << "Created phi of ops " << *ValuePHI << " for " << *Ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Created phi of ops " << *
ValuePHI << " for " << *I << "\n"; } } while
(false)
2846 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Created phi of ops " << *
ValuePHI << " for " << *I << "\n"; } } while
(false)
;
2847
2848 return E;
2849}
2850
2851// The algorithm initially places the values of the routine in the TOP
2852// congruence class. The leader of TOP is the undetermined value `undef`.
2853// When the algorithm has finished, values still in TOP are unreachable.
2854void NewGVN::initializeCongruenceClasses(Function &F) {
2855 NextCongruenceNum = 0;
2856
2857 // Note that even though we use the live on entry def as a representative
2858 // MemoryAccess, it is *not* the same as the actual live on entry def. We
2859 // have no real equivalemnt to undef for MemoryAccesses, and so we really
2860 // should be checking whether the MemoryAccess is top if we want to know if it
2861 // is equivalent to everything. Otherwise, what this really signifies is that
2862 // the access "it reaches all the way back to the beginning of the function"
2863
2864 // Initialize all other instructions to be in TOP class.
2865 TOPClass = createCongruenceClass(nullptr, nullptr);
2866 TOPClass->setMemoryLeader(MSSA->getLiveOnEntryDef());
2867 // The live on entry def gets put into it's own class
2868 MemoryAccessToClass[MSSA->getLiveOnEntryDef()] =
2869 createMemoryClass(MSSA->getLiveOnEntryDef());
2870
2871 for (auto DTN : nodes(DT)) {
2872 BasicBlock *BB = DTN->getBlock();
2873 // All MemoryAccesses are equivalent to live on entry to start. They must
2874 // be initialized to something so that initial changes are noticed. For
2875 // the maximal answer, we initialize them all to be the same as
2876 // liveOnEntry.
2877 auto *MemoryBlockDefs = MSSA->getBlockDefs(BB);
2878 if (MemoryBlockDefs)
2879 for (const auto &Def : *MemoryBlockDefs) {
2880 MemoryAccessToClass[&Def] = TOPClass;
2881 auto *MD = dyn_cast<MemoryDef>(&Def);
2882 // Insert the memory phis into the member list.
2883 if (!MD) {
2884 const MemoryPhi *MP = cast<MemoryPhi>(&Def);
2885 TOPClass->memory_insert(MP);
2886 MemoryPhiState.insert({MP, MPS_TOP});
2887 }
2888
2889 if (MD && isa<StoreInst>(MD->getMemoryInst()))
2890 TOPClass->incStoreCount();
2891 }
2892
2893 // FIXME: This is trying to discover which instructions are uses of phi
2894 // nodes. We should move this into one of the myriad of places that walk
2895 // all the operands already.
2896 for (auto &I : *BB) {
2897 if (isa<PHINode>(&I))
2898 for (auto *U : I.users())
2899 if (auto *UInst = dyn_cast<Instruction>(U))
2900 if (InstrToDFSNum(UInst) != 0 && okayForPHIOfOps(UInst))
2901 PHINodeUses.insert(UInst);
2902 // Don't insert void terminators into the class. We don't value number
2903 // them, and they just end up sitting in TOP.
2904 if (I.isTerminator() && I.getType()->isVoidTy())
2905 continue;
2906 TOPClass->insert(&I);
2907 ValueToClass[&I] = TOPClass;
2908 }
2909 }
2910
2911 // Initialize arguments to be in their own unique congruence classes
2912 for (auto &FA : F.args())
2913 createSingletonCongruenceClass(&FA);
2914}
2915
2916void NewGVN::cleanupTables() {
2917 for (unsigned i = 0, e = CongruenceClasses.size(); i != e; ++i) {
2918 LLVM_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)
2919 << " has " << CongruenceClasses[i]->size()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Congruence class " << CongruenceClasses
[i]->getID() << " has " << CongruenceClasses[i
]->size() << " members\n"; } } while (false)
2920 << " members\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Congruence class " << CongruenceClasses
[i]->getID() << " has " << CongruenceClasses[i
]->size() << " members\n"; } } while (false)
;
2921 // Make sure we delete the congruence class (probably worth switching to
2922 // a unique_ptr at some point.
2923 delete CongruenceClasses[i];
2924 CongruenceClasses[i] = nullptr;
2925 }
2926
2927 // Destroy the value expressions
2928 SmallVector<Instruction *, 8> TempInst(AllTempInstructions.begin(),
2929 AllTempInstructions.end());
2930 AllTempInstructions.clear();
2931
2932 // We have to drop all references for everything first, so there are no uses
2933 // left as we delete them.
2934 for (auto *I : TempInst) {
2935 I->dropAllReferences();
2936 }
2937
2938 while (!TempInst.empty()) {
2939 auto *I = TempInst.back();
2940 TempInst.pop_back();
2941 I->deleteValue();
2942 }
2943
2944 ValueToClass.clear();
2945 ArgRecycler.clear(ExpressionAllocator);
2946 ExpressionAllocator.Reset();
2947 CongruenceClasses.clear();
2948 ExpressionToClass.clear();
2949 ValueToExpression.clear();
2950 RealToTemp.clear();
2951 AdditionalUsers.clear();
2952 ExpressionToPhiOfOps.clear();
2953 TempToBlock.clear();
2954 TempToMemory.clear();
2955 PHINodeUses.clear();
2956 OpSafeForPHIOfOps.clear();
2957 ReachableBlocks.clear();
2958 ReachableEdges.clear();
2959#ifndef NDEBUG
2960 ProcessedCount.clear();
2961#endif
2962 InstrDFS.clear();
2963 InstructionsToErase.clear();
2964 DFSToInstr.clear();
2965 BlockInstRange.clear();
2966 TouchedInstructions.clear();
2967 MemoryAccessToClass.clear();
2968 PredicateToUsers.clear();
2969 MemoryToUsers.clear();
2970 RevisitOnReachabilityChange.clear();
2971}
2972
2973// Assign local DFS number mapping to instructions, and leave space for Value
2974// PHI's.
2975std::pair<unsigned, unsigned> NewGVN::assignDFSNumbers(BasicBlock *B,
2976 unsigned Start) {
2977 unsigned End = Start;
2978 if (MemoryAccess *MemPhi = getMemoryAccess(B)) {
2979 InstrDFS[MemPhi] = End++;
2980 DFSToInstr.emplace_back(MemPhi);
2981 }
2982
2983 // Then the real block goes next.
2984 for (auto &I : *B) {
2985 // There's no need to call isInstructionTriviallyDead more than once on
2986 // an instruction. Therefore, once we know that an instruction is dead
2987 // we change its DFS number so that it doesn't get value numbered.
2988 if (isInstructionTriviallyDead(&I, TLI)) {
2989 InstrDFS[&I] = 0;
2990 LLVM_DEBUG(dbgs() << "Skipping trivially dead instruction " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping trivially dead instruction "
<< I << "\n"; } } while (false)
;
2991 markInstructionForDeletion(&I);
2992 continue;
2993 }
2994 if (isa<PHINode>(&I))
2995 RevisitOnReachabilityChange[B].set(End);
2996 InstrDFS[&I] = End++;
2997 DFSToInstr.emplace_back(&I);
2998 }
2999
3000 // All of the range functions taken half-open ranges (open on the end side).
3001 // So we do not subtract one from count, because at this point it is one
3002 // greater than the last instruction.
3003 return std::make_pair(Start, End);
3004}
3005
3006void NewGVN::updateProcessedCount(const Value *V) {
3007#ifndef NDEBUG
3008 if (ProcessedCount.count(V) == 0) {
3009 ProcessedCount.insert({V, 1});
3010 } else {
3011 ++ProcessedCount[V];
3012 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3013, __PRETTY_FUNCTION__))
3013 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3013, __PRETTY_FUNCTION__))
;
3014 }
3015#endif
3016}
3017
3018// Evaluate MemoryPhi nodes symbolically, just like PHI nodes
3019void NewGVN::valueNumberMemoryPhi(MemoryPhi *MP) {
3020 // If all the arguments are the same, the MemoryPhi has the same value as the
3021 // argument. Filter out unreachable blocks and self phis from our operands.
3022 // TODO: We could do cycle-checking on the memory phis to allow valueizing for
3023 // self-phi checking.
3024 const BasicBlock *PHIBlock = MP->getBlock();
3025 auto Filtered = make_filter_range(MP->operands(), [&](const Use &U) {
3026 return cast<MemoryAccess>(U) != MP &&
3027 !isMemoryAccessTOP(cast<MemoryAccess>(U)) &&
3028 ReachableEdges.count({MP->getIncomingBlock(U), PHIBlock});
3029 });
3030 // If all that is left is nothing, our memoryphi is undef. We keep it as
3031 // InitialClass. Note: The only case this should happen is if we have at
3032 // least one self-argument.
3033 if (Filtered.begin() == Filtered.end()) {
3034 if (setMemoryClass(MP, TOPClass))
3035 markMemoryUsersTouched(MP);
3036 return;
3037 }
3038
3039 // Transform the remaining operands into operand leaders.
3040 // FIXME: mapped_iterator should have a range version.
3041 auto LookupFunc = [&](const Use &U) {
3042 return lookupMemoryLeader(cast<MemoryAccess>(U));
3043 };
3044 auto MappedBegin = map_iterator(Filtered.begin(), LookupFunc);
3045 auto MappedEnd = map_iterator(Filtered.end(), LookupFunc);
3046
3047 // and now check if all the elements are equal.
3048 // Sadly, we can't use std::equals since these are random access iterators.
3049 const auto *AllSameValue = *MappedBegin;
3050 ++MappedBegin;
3051 bool AllEqual = std::all_of(
3052 MappedBegin, MappedEnd,
3053 [&AllSameValue](const MemoryAccess *V) { return V == AllSameValue; });
3054
3055 if (AllEqual)
3056 LLVM_DEBUG(dbgs() << "Memory Phi value numbered to " << *AllSameValuedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory Phi value numbered to "
<< *AllSameValue << "\n"; } } while (false)
3057 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory Phi value numbered to "
<< *AllSameValue << "\n"; } } while (false)
;
3058 else
3059 LLVM_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)
;
3060 // If it's equal to something, it's in that class. Otherwise, it has to be in
3061 // a class where it is the leader (other things may be equivalent to it, but
3062 // it needs to start off in its own class, which means it must have been the
3063 // leader, and it can't have stopped being the leader because it was never
3064 // removed).
3065 CongruenceClass *CC =
3066 AllEqual ? getMemoryClass(AllSameValue) : ensureLeaderOfMemoryClass(MP);
3067 auto OldState = MemoryPhiState.lookup(MP);
3068 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3068, __PRETTY_FUNCTION__))
;
3069 auto NewState = AllEqual ? MPS_Equivalent : MPS_Unique;
3070 MemoryPhiState[MP] = NewState;
3071 if (setMemoryClass(MP, CC) || OldState != NewState)
3072 markMemoryUsersTouched(MP);
3073}
3074
3075// Value number a single instruction, symbolically evaluating, performing
3076// congruence finding, and updating mappings.
3077void NewGVN::valueNumberInstruction(Instruction *I) {
3078 LLVM_DEBUG(dbgs() << "Processing instruction " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Processing instruction " <<
*I << "\n"; } } while (false)
;
3079 if (!I->isTerminator()) {
3080 const Expression *Symbolized = nullptr;
3081 SmallPtrSet<Value *, 2> Visited;
3082 if (DebugCounter::shouldExecute(VNCounter)) {
3083 Symbolized = performSymbolicEvaluation(I, Visited);
3084 // Make a phi of ops if necessary
3085 if (Symbolized && !isa<ConstantExpression>(Symbolized) &&
3086 !isa<VariableExpression>(Symbolized) && PHINodeUses.count(I)) {
3087 auto *PHIE = makePossiblePHIOfOps(I, Visited);
3088 // If we created a phi of ops, use it.
3089 // If we couldn't create one, make sure we don't leave one lying around
3090 if (PHIE) {
3091 Symbolized = PHIE;
3092 } else if (auto *Op = RealToTemp.lookup(I)) {
3093 removePhiOfOps(I, Op);
3094 }
3095 }
3096 } else {
3097 // Mark the instruction as unused so we don't value number it again.
3098 InstrDFS[I] = 0;
3099 }
3100 // If we couldn't come up with a symbolic expression, use the unknown
3101 // expression
3102 if (Symbolized == nullptr)
3103 Symbolized = createUnknownExpression(I);
3104 performCongruenceFinding(I, Symbolized);
3105 } else {
3106 // Handle terminators that return values. All of them produce values we
3107 // don't currently understand. We don't place non-value producing
3108 // terminators in a class.
3109 if (!I->getType()->isVoidTy()) {
3110 auto *Symbolized = createUnknownExpression(I);
3111 performCongruenceFinding(I, Symbolized);
3112 }
3113 processOutgoingEdges(I, I->getParent());
3114 }
3115}
3116
3117// Check if there is a path, using single or equal argument phi nodes, from
3118// First to Second.
3119bool NewGVN::singleReachablePHIPath(
3120 SmallPtrSet<const MemoryAccess *, 8> &Visited, const MemoryAccess *First,
3121 const MemoryAccess *Second) const {
3122 if (First == Second)
3123 return true;
3124 if (MSSA->isLiveOnEntryDef(First))
3125 return false;
3126
3127 // This is not perfect, but as we're just verifying here, we can live with
3128 // the loss of precision. The real solution would be that of doing strongly
3129 // connected component finding in this routine, and it's probably not worth
3130 // the complexity for the time being. So, we just keep a set of visited
3131 // MemoryAccess and return true when we hit a cycle.
3132 if (Visited.count(First))
3133 return true;
3134 Visited.insert(First);
3135
3136 const auto *EndDef = First;
3137 for (auto *ChainDef : optimized_def_chain(First)) {
3138 if (ChainDef == Second)
3139 return true;
3140 if (MSSA->isLiveOnEntryDef(ChainDef))
3141 return false;
3142 EndDef = ChainDef;
3143 }
3144 auto *MP = cast<MemoryPhi>(EndDef);
3145 auto ReachableOperandPred = [&](const Use &U) {
3146 return ReachableEdges.count({MP->getIncomingBlock(U), MP->getBlock()});
3147 };
3148 auto FilteredPhiArgs =
3149 make_filter_range(MP->operands(), ReachableOperandPred);
3150 SmallVector<const Value *, 32> OperandList;
3151 llvm::copy(FilteredPhiArgs, std::back_inserter(OperandList));
3152 bool Okay = is_splat(OperandList);
3153 if (Okay)
3154 return singleReachablePHIPath(Visited, cast<MemoryAccess>(OperandList[0]),
3155 Second);
3156 return false;
3157}
3158
3159// Verify the that the memory equivalence table makes sense relative to the
3160// congruence classes. Note that this checking is not perfect, and is currently
3161// subject to very rare false negatives. It is only useful for
3162// testing/debugging.
3163void NewGVN::verifyMemoryCongruency() const {
3164#ifndef NDEBUG
3165 // Verify that the memory table equivalence and memory member set match
3166 for (const auto *CC : CongruenceClasses) {
3167 if (CC == TOPClass || CC->isDead())
3168 continue;
3169 if (CC->getStoreCount() != 0) {
3170 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") ? 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3172, __PRETTY_FUNCTION__))
3171 "Any class with a store as a leader should have a "(((CC->getStoredValue() || !isa<StoreInst>(CC->getLeader
())) && "Any class with a store as a leader should have a "
"representative stored value") ? 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3172, __PRETTY_FUNCTION__))
3172 "representative stored value")(((CC->getStoredValue() || !isa<StoreInst>(CC->getLeader
())) && "Any class with a store as a leader should have a "
"representative stored value") ? 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3172, __PRETTY_FUNCTION__))
;
3173 assert(CC->getMemoryLeader() &&((CC->getMemoryLeader() && "Any congruence class with a store should have a "
"representative access") ? static_cast<void> (0) : __assert_fail
("CC->getMemoryLeader() && \"Any congruence class with a store should have a \" \"representative access\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3175, __PRETTY_FUNCTION__))
3174 "Any congruence class with a store should have a "((CC->getMemoryLeader() && "Any congruence class with a store should have a "
"representative access") ? static_cast<void> (0) : __assert_fail
("CC->getMemoryLeader() && \"Any congruence class with a store should have a \" \"representative access\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3175, __PRETTY_FUNCTION__))
3175 "representative access")((CC->getMemoryLeader() && "Any congruence class with a store should have a "
"representative access") ? static_cast<void> (0) : __assert_fail
("CC->getMemoryLeader() && \"Any congruence class with a store should have a \" \"representative access\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3175, __PRETTY_FUNCTION__))
;
3176 }
3177
3178 if (CC->getMemoryLeader())
3179 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3181, __PRETTY_FUNCTION__))
3180 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3181, __PRETTY_FUNCTION__))
3181 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3181, __PRETTY_FUNCTION__))
;
3182 for (auto M : CC->memory())
3183 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3184, __PRETTY_FUNCTION__))
3184 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3184, __PRETTY_FUNCTION__))
;
3185 }
3186
3187 // Anything equivalent in the MemoryAccess table should be in the same
3188 // congruence class.
3189
3190 // Filter out the unreachable and trivially dead entries, because they may
3191 // never have been updated if the instructions were not processed.
3192 auto ReachableAccessPred =
3193 [&](const std::pair<const MemoryAccess *, CongruenceClass *> Pair) {
3194 bool Result = ReachableBlocks.count(Pair.first->getBlock());
3195 if (!Result || MSSA->isLiveOnEntryDef(Pair.first) ||
3196 MemoryToDFSNum(Pair.first) == 0)
3197 return false;
3198 if (auto *MemDef = dyn_cast<MemoryDef>(Pair.first))
3199 return !isInstructionTriviallyDead(MemDef->getMemoryInst());
3200
3201 // We could have phi nodes which operands are all trivially dead,
3202 // so we don't process them.
3203 if (auto *MemPHI = dyn_cast<MemoryPhi>(Pair.first)) {
3204 for (auto &U : MemPHI->incoming_values()) {
3205 if (auto *I = dyn_cast<Instruction>(&*U)) {
3206 if (!isInstructionTriviallyDead(I))
3207 return true;
3208 }
3209 }
3210 return false;
3211 }
3212
3213 return true;
3214 };
3215
3216 auto Filtered = make_filter_range(MemoryAccessToClass, ReachableAccessPred);
3217 for (auto KV : Filtered) {
3218 if (auto *FirstMUD = dyn_cast<MemoryUseOrDef>(KV.first)) {
3219 auto *SecondMUD = dyn_cast<MemoryUseOrDef>(KV.second->getMemoryLeader());
3220 if (FirstMUD && SecondMUD) {
3221 SmallPtrSet<const MemoryAccess *, 8> VisitedMAS;
3222 assert((singleReachablePHIPath(VisitedMAS, FirstMUD, SecondMUD) ||(((singleReachablePHIPath(VisitedMAS, 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(VisitedMAS, 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3227, __PRETTY_FUNCTION__))
3223 ValueToClass.lookup(FirstMUD->getMemoryInst()) ==(((singleReachablePHIPath(VisitedMAS, 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(VisitedMAS, 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3227, __PRETTY_FUNCTION__))
3224 ValueToClass.lookup(SecondMUD->getMemoryInst())) &&(((singleReachablePHIPath(VisitedMAS, 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(VisitedMAS, 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3227, __PRETTY_FUNCTION__))
3225 "The instructions for these memory operations should have "(((singleReachablePHIPath(VisitedMAS, 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(VisitedMAS, 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3227, __PRETTY_FUNCTION__))
3226 "been in the same congruence class or reachable through"(((singleReachablePHIPath(VisitedMAS, 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(VisitedMAS, 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3227, __PRETTY_FUNCTION__))
3227 "a single argument phi")(((singleReachablePHIPath(VisitedMAS, 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(VisitedMAS, 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3227, __PRETTY_FUNCTION__))
;
3228 }
3229 } else if (auto *FirstMP = dyn_cast<MemoryPhi>(KV.first)) {
3230 // We can only sanely verify that MemoryDefs in the operand list all have
3231 // the same class.
3232 auto ReachableOperandPred = [&](const Use &U) {
3233 return ReachableEdges.count(
3234 {FirstMP->getIncomingBlock(U), FirstMP->getBlock()}) &&
3235 isa<MemoryDef>(U);
3236
3237 };
3238 // All arguments should in the same class, ignoring unreachable arguments
3239 auto FilteredPhiArgs =
3240 make_filter_range(FirstMP->operands(), ReachableOperandPred);
3241 SmallVector<const CongruenceClass *, 16> PhiOpClasses;
3242 std::transform(FilteredPhiArgs.begin(), FilteredPhiArgs.end(),
3243 std::back_inserter(PhiOpClasses), [&](const Use &U) {
3244 const MemoryDef *MD = cast<MemoryDef>(U);
3245 return ValueToClass.lookup(MD->getMemoryInst());
3246 });
3247 assert(is_splat(PhiOpClasses) &&((is_splat(PhiOpClasses) && "All MemoryPhi arguments should be in the same class"
) ? static_cast<void> (0) : __assert_fail ("is_splat(PhiOpClasses) && \"All MemoryPhi arguments should be in the same class\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3248, __PRETTY_FUNCTION__))
3248 "All MemoryPhi arguments should be in the same class")((is_splat(PhiOpClasses) && "All MemoryPhi arguments should be in the same class"
) ? static_cast<void> (0) : __assert_fail ("is_splat(PhiOpClasses) && \"All MemoryPhi arguments should be in the same class\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3248, __PRETTY_FUNCTION__))
;
3249 }
3250 }
3251#endif
3252}
3253
3254// Verify that the sparse propagation we did actually found the maximal fixpoint
3255// We do this by storing the value to class mapping, touching all instructions,
3256// and redoing the iteration to see if anything changed.
3257void NewGVN::verifyIterationSettled(Function &F) {
3258#ifndef NDEBUG
3259 LLVM_DEBUG(dbgs() << "Beginning iteration verification\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Beginning iteration verification\n"
; } } while (false)
;
3260 if (DebugCounter::isCounterSet(VNCounter))
3261 DebugCounter::setCounterValue(VNCounter, StartingVNCounter);
3262
3263 // Note that we have to store the actual classes, as we may change existing
3264 // classes during iteration. This is because our memory iteration propagation
3265 // is not perfect, and so may waste a little work. But it should generate
3266 // exactly the same congruence classes we have now, with different IDs.
3267 std::map<const Value *, CongruenceClass> BeforeIteration;
3268
3269 for (auto &KV : ValueToClass) {
3270 if (auto *I = dyn_cast<Instruction>(KV.first))
3271 // Skip unused/dead instructions.
3272 if (InstrToDFSNum(I) == 0)
3273 continue;
3274 BeforeIteration.insert({KV.first, *KV.second});
3275 }
3276
3277 TouchedInstructions.set();
3278 TouchedInstructions.reset(0);
3279 iterateTouchedInstructions();
3280 DenseSet<std::pair<const CongruenceClass *, const CongruenceClass *>>
3281 EqualClasses;
3282 for (const auto &KV : ValueToClass) {
3283 if (auto *I = dyn_cast<Instruction>(KV.first))
3284 // Skip unused/dead instructions.
3285 if (InstrToDFSNum(I) == 0)
3286 continue;
3287 // We could sink these uses, but i think this adds a bit of clarity here as
3288 // to what we are comparing.
3289 auto *BeforeCC = &BeforeIteration.find(KV.first)->second;
3290 auto *AfterCC = KV.second;
3291 // Note that the classes can't change at this point, so we memoize the set
3292 // that are equal.
3293 if (!EqualClasses.count({BeforeCC, AfterCC})) {
3294 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!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3295, __PRETTY_FUNCTION__))
3295 "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!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3295, __PRETTY_FUNCTION__))
;
3296 EqualClasses.insert({BeforeCC, AfterCC});
3297 }
3298 }
3299#endif
3300}
3301
3302// Verify that for each store expression in the expression to class mapping,
3303// only the latest appears, and multiple ones do not appear.
3304// Because loads do not use the stored value when doing equality with stores,
3305// if we don't erase the old store expressions from the table, a load can find
3306// a no-longer valid StoreExpression.
3307void NewGVN::verifyStoreExpressions() const {
3308#ifndef NDEBUG
3309 // This is the only use of this, and it's not worth defining a complicated
3310 // densemapinfo hash/equality function for it.
3311 std::set<
3312 std::pair<const Value *,
3313 std::tuple<const Value *, const CongruenceClass *, Value *>>>
3314 StoreExpressionSet;
3315 for (const auto &KV : ExpressionToClass) {
3316 if (auto *SE = dyn_cast<StoreExpression>(KV.first)) {
3317 // Make sure a version that will conflict with loads is not already there
3318 auto Res = StoreExpressionSet.insert(
3319 {SE->getOperand(0), std::make_tuple(SE->getMemoryLeader(), KV.second,
3320 SE->getStoredValue())});
3321 bool Okay = Res.second;
3322 // It's okay to have the same expression already in there if it is
3323 // identical in nature.
3324 // This can happen when the leader of the stored value changes over time.
3325 if (!Okay)
3326 Okay = (std::get<1>(Res.first->second) == KV.second) &&
3327 (lookupOperandLeader(std::get<2>(Res.first->second)) ==
3328 lookupOperandLeader(SE->getStoredValue()));
3329 assert(Okay && "Stored expression conflict exists in expression table")((Okay && "Stored expression conflict exists in expression table"
) ? static_cast<void> (0) : __assert_fail ("Okay && \"Stored expression conflict exists in expression table\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3329, __PRETTY_FUNCTION__))
;
3330 auto *ValueExpr = ValueToExpression.lookup(SE->getStoreInst());
3331 assert(ValueExpr && ValueExpr->equals(*SE) &&((ValueExpr && ValueExpr->equals(*SE) && "StoreExpression in ExpressionToClass is not latest "
"StoreExpression for value") ? static_cast<void> (0) :
__assert_fail ("ValueExpr && ValueExpr->equals(*SE) && \"StoreExpression in ExpressionToClass is not latest \" \"StoreExpression for value\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3333, __PRETTY_FUNCTION__))
3332 "StoreExpression in ExpressionToClass is not latest "((ValueExpr && ValueExpr->equals(*SE) && "StoreExpression in ExpressionToClass is not latest "
"StoreExpression for value") ? static_cast<void> (0) :
__assert_fail ("ValueExpr && ValueExpr->equals(*SE) && \"StoreExpression in ExpressionToClass is not latest \" \"StoreExpression for value\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3333, __PRETTY_FUNCTION__))
3333 "StoreExpression for value")((ValueExpr && ValueExpr->equals(*SE) && "StoreExpression in ExpressionToClass is not latest "
"StoreExpression for value") ? static_cast<void> (0) :
__assert_fail ("ValueExpr && ValueExpr->equals(*SE) && \"StoreExpression in ExpressionToClass is not latest \" \"StoreExpression for value\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3333, __PRETTY_FUNCTION__))
;
3334 }
3335 }
3336#endif
3337}
3338
3339// This is the main value numbering loop, it iterates over the initial touched
3340// instruction set, propagating value numbers, marking things touched, etc,
3341// until the set of touched instructions is completely empty.
3342void NewGVN::iterateTouchedInstructions() {
3343 unsigned int Iterations = 0;
3344 // Figure out where touchedinstructions starts
3345 int FirstInstr = TouchedInstructions.find_first();
3346 // Nothing set, nothing to iterate, just return.
3347 if (FirstInstr == -1)
3348 return;
3349 const BasicBlock *LastBlock = getBlockForValue(InstrFromDFSNum(FirstInstr));
3350 while (TouchedInstructions.any()) {
3351 ++Iterations;
3352 // Walk through all the instructions in all the blocks in RPO.
3353 // TODO: As we hit a new block, we should push and pop equalities into a
3354 // table lookupOperandLeader can use, to catch things PredicateInfo
3355 // might miss, like edge-only equivalences.
3356 for (unsigned InstrNum : TouchedInstructions.set_bits()) {
3357
3358 // This instruction was found to be dead. We don't bother looking
3359 // at it again.
3360 if (InstrNum == 0) {
3361 TouchedInstructions.reset(InstrNum);
3362 continue;
3363 }
3364
3365 Value *V = InstrFromDFSNum(InstrNum);
3366 const BasicBlock *CurrBlock = getBlockForValue(V);
3367
3368 // If we hit a new block, do reachability processing.
3369 if (CurrBlock != LastBlock) {
3370 LastBlock = CurrBlock;
3371 bool BlockReachable = ReachableBlocks.count(CurrBlock);
3372 const auto &CurrInstRange = BlockInstRange.lookup(CurrBlock);
3373
3374 // If it's not reachable, erase any touched instructions and move on.
3375 if (!BlockReachable) {
3376 TouchedInstructions.reset(CurrInstRange.first, CurrInstRange.second);
3377 LLVM_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)
3378 << getBlockName(CurrBlock)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping instructions in block "
<< getBlockName(CurrBlock) << " because it is unreachable\n"
; } } while (false)
3379 << " 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)
;
3380 continue;
3381 }
3382 updateProcessedCount(CurrBlock);
3383 }
3384 // Reset after processing (because we may mark ourselves as touched when
3385 // we propagate equalities).
3386 TouchedInstructions.reset(InstrNum);
3387
3388 if (auto *MP = dyn_cast<MemoryPhi>(V)) {
3389 LLVM_DEBUG(dbgs() << "Processing MemoryPhi " << *MP << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Processing MemoryPhi " <<
*MP << "\n"; } } while (false)
;
3390 valueNumberMemoryPhi(MP);
3391 } else if (auto *I = dyn_cast<Instruction>(V)) {
3392 valueNumberInstruction(I);
3393 } else {
3394 llvm_unreachable("Should have been a MemoryPhi or Instruction")::llvm::llvm_unreachable_internal("Should have been a MemoryPhi or Instruction"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3394)
;
3395 }
3396 updateProcessedCount(V);
3397 }
3398 }
3399 NumGVNMaxIterations = std::max(NumGVNMaxIterations.getValue(), Iterations);
3400}
3401
3402// This is the main transformation entry point.
3403bool NewGVN::runGVN() {
3404 if (DebugCounter::isCounterSet(VNCounter))
3405 StartingVNCounter = DebugCounter::getCounterValue(VNCounter);
3406 bool Changed = false;
3407 NumFuncArgs = F.arg_size();
3408 MSSAWalker = MSSA->getWalker();
3409 SingletonDeadExpression = new (ExpressionAllocator) DeadExpression();
3410
3411 // Count number of instructions for sizing of hash tables, and come
3412 // up with a global dfs numbering for instructions.
3413 unsigned ICount = 1;
3414 // Add an empty instruction to account for the fact that we start at 1
3415 DFSToInstr.emplace_back(nullptr);
3416 // Note: We want ideal RPO traversal of the blocks, which is not quite the
3417 // same as dominator tree order, particularly with regard whether backedges
3418 // get visited first or second, given a block with multiple successors.
3419 // If we visit in the wrong order, we will end up performing N times as many
3420 // iterations.
3421 // The dominator tree does guarantee that, for a given dom tree node, it's
3422 // parent must occur before it in the RPO ordering. Thus, we only need to sort
3423 // the siblings.
3424 ReversePostOrderTraversal<Function *> RPOT(&F);
3425 unsigned Counter = 0;
3426 for (auto &B : RPOT) {
3427 auto *Node = DT->getNode(B);
3428 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3428, __PRETTY_FUNCTION__))
;
3429 RPOOrdering[Node] = ++Counter;
3430 }
3431 // Sort dominator tree children arrays into RPO.
3432 for (auto &B : RPOT) {
3433 auto *Node = DT->getNode(B);
3434 if (Node->getChildren().size() > 1)
3435 llvm::sort(Node->begin(), Node->end(),
3436 [&](const DomTreeNode *A, const DomTreeNode *B) {
3437 return RPOOrdering[A] < RPOOrdering[B];
3438 });
3439 }
3440
3441 // Now a standard depth first ordering of the domtree is equivalent to RPO.
3442 for (auto DTN : depth_first(DT->getRootNode())) {
3443 BasicBlock *B = DTN->getBlock();
3444 const auto &BlockRange = assignDFSNumbers(B, ICount);
3445 BlockInstRange.insert({B, BlockRange});
3446 ICount += BlockRange.second - BlockRange.first;
3447 }
3448 initializeCongruenceClasses(F);
3449
3450 TouchedInstructions.resize(ICount);
3451 // Ensure we don't end up resizing the expressionToClass map, as
3452 // that can be quite expensive. At most, we have one expression per
3453 // instruction.
3454 ExpressionToClass.reserve(ICount);
3455
3456 // Initialize the touched instructions to include the entry block.
3457 const auto &InstRange = BlockInstRange.lookup(&F.getEntryBlock());
3458 TouchedInstructions.set(InstRange.first, InstRange.second);
3459 LLVM_DEBUG(dbgs() << "Block " << getBlockName(&F.getEntryBlock())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
&F.getEntryBlock()) << " marked reachable\n"; } } while
(false)
3460 << " marked reachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
&F.getEntryBlock()) << " marked reachable\n"; } } while
(false)
;
3461 ReachableBlocks.insert(&F.getEntryBlock());
3462
3463 iterateTouchedInstructions();
3464 verifyMemoryCongruency();
3465 verifyIterationSettled(F);
3466 verifyStoreExpressions();
3467
3468 Changed |= eliminateInstructions(F);
3469
3470 // Delete all instructions marked for deletion.
3471 for (Instruction *ToErase : InstructionsToErase) {
3472 if (!ToErase->use_empty())
3473 ToErase->replaceAllUsesWith(UndefValue::get(ToErase->getType()));
3474
3475 assert(ToErase->getParent() &&((ToErase->getParent() && "BB containing ToErase deleted unexpectedly!"
) ? static_cast<void> (0) : __assert_fail ("ToErase->getParent() && \"BB containing ToErase deleted unexpectedly!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3476, __PRETTY_FUNCTION__))
3476 "BB containing ToErase deleted unexpectedly!")((ToErase->getParent() && "BB containing ToErase deleted unexpectedly!"
) ? static_cast<void> (0) : __assert_fail ("ToErase->getParent() && \"BB containing ToErase deleted unexpectedly!\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3476, __PRETTY_FUNCTION__))
;
3477 ToErase->eraseFromParent();
3478 }
3479 Changed |= !InstructionsToErase.empty();
3480
3481 // Delete all unreachable blocks.
3482 auto UnreachableBlockPred = [&](const BasicBlock &BB) {
3483 return !ReachableBlocks.count(&BB);
3484 };
3485
3486 for (auto &BB : make_filter_range(F, UnreachableBlockPred)) {
3487 LLVM_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)
3488 << " is unreachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "We believe block " << getBlockName
(&BB) << " is unreachable\n"; } } while (false)
;
3489 deleteInstructionsInBlock(&BB);
3490 Changed = true;
3491 }
3492
3493 cleanupTables();
3494 return Changed;
3495}
3496
3497struct NewGVN::ValueDFS {
3498 int DFSIn = 0;
3499 int DFSOut = 0;
3500 int LocalNum = 0;
3501
3502 // Only one of Def and U will be set.
3503 // The bool in the Def tells us whether the Def is the stored value of a
3504 // store.
3505 PointerIntPair<Value *, 1, bool> Def;
3506 Use *U = nullptr;
3507
3508 bool operator<(const ValueDFS &Other) const {
3509 // It's not enough that any given field be less than - we have sets
3510 // of fields that need to be evaluated together to give a proper ordering.
3511 // For example, if you have;
3512 // DFS (1, 3)
3513 // Val 0
3514 // DFS (1, 2)
3515 // Val 50
3516 // We want the second to be less than the first, but if we just go field
3517 // by field, we will get to Val 0 < Val 50 and say the first is less than
3518 // the second. We only want it to be less than if the DFS orders are equal.
3519 //
3520 // Each LLVM instruction only produces one value, and thus the lowest-level
3521 // differentiator that really matters for the stack (and what we use as as a
3522 // replacement) is the local dfs number.
3523 // Everything else in the structure is instruction level, and only affects
3524 // the order in which we will replace operands of a given instruction.
3525 //
3526 // For a given instruction (IE things with equal dfsin, dfsout, localnum),
3527 // the order of replacement of uses does not matter.
3528 // IE given,
3529 // a = 5
3530 // b = a + a
3531 // When you hit b, you will have two valuedfs with the same dfsin, out, and
3532 // localnum.
3533 // The .val will be the same as well.
3534 // The .u's will be different.
3535 // You will replace both, and it does not matter what order you replace them
3536 // in (IE whether you replace operand 2, then operand 1, or operand 1, then
3537 // operand 2).
3538 // Similarly for the case of same dfsin, dfsout, localnum, but different
3539 // .val's
3540 // a = 5
3541 // b = 6
3542 // c = a + b
3543 // in c, we will a valuedfs for a, and one for b,with everything the same
3544 // but .val and .u.
3545 // It does not matter what order we replace these operands in.
3546 // You will always end up with the same IR, and this is guaranteed.
3547 return std::tie(DFSIn, DFSOut, LocalNum, Def, U) <
3548 std::tie(Other.DFSIn, Other.DFSOut, Other.LocalNum, Other.Def,
3549 Other.U);
3550 }
3551};
3552
3553// This function converts the set of members for a congruence class from values,
3554// to sets of defs and uses with associated DFS info. The total number of
3555// reachable uses for each value is stored in UseCount, and instructions that
3556// seem
3557// dead (have no non-dead uses) are stored in ProbablyDead.
3558void NewGVN::convertClassToDFSOrdered(
3559 const CongruenceClass &Dense, SmallVectorImpl<ValueDFS> &DFSOrderedSet,
3560 DenseMap<const Value *, unsigned int> &UseCounts,
3561 SmallPtrSetImpl<Instruction *> &ProbablyDead) const {
3562 for (auto D : Dense) {
3563 // First add the value.
3564 BasicBlock *BB = getBlockForValue(D);
3565 // Constants are handled prior to ever calling this function, so
3566 // we should only be left with instructions as members.
3567 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3567, __PRETTY_FUNCTION__))
;
3568 ValueDFS VDDef;
3569 DomTreeNode *DomNode = DT->getNode(BB);
3570 VDDef.DFSIn = DomNode->getDFSNumIn();
3571 VDDef.DFSOut = DomNode->getDFSNumOut();
3572 // If it's a store, use the leader of the value operand, if it's always
3573 // available, or the value operand. TODO: We could do dominance checks to
3574 // find a dominating leader, but not worth it ATM.
3575 if (auto *SI = dyn_cast<StoreInst>(D)) {
3576 auto Leader = lookupOperandLeader(SI->getValueOperand());
3577 if (alwaysAvailable(Leader)) {
3578 VDDef.Def.setPointer(Leader);
3579 } else {
3580 VDDef.Def.setPointer(SI->getValueOperand());
3581 VDDef.Def.setInt(true);
3582 }
3583 } else {
3584 VDDef.Def.setPointer(D);
3585 }
3586 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3587, __PRETTY_FUNCTION__))
3587 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3587, __PRETTY_FUNCTION__))
;
3588 Instruction *Def = cast<Instruction>(D);
3589 VDDef.LocalNum = InstrToDFSNum(D);
3590 DFSOrderedSet.push_back(VDDef);
3591 // If there is a phi node equivalent, add it
3592 if (auto *PN = RealToTemp.lookup(Def)) {
3593 auto *PHIE =
3594 dyn_cast_or_null<PHIExpression>(ValueToExpression.lookup(Def));
3595 if (PHIE) {
3596 VDDef.Def.setInt(false);
3597 VDDef.Def.setPointer(PN);
3598 VDDef.LocalNum = 0;
3599 DFSOrderedSet.push_back(VDDef);
3600 }
3601 }
3602
3603 unsigned int UseCount = 0;
3604 // Now add the uses.
3605 for (auto &U : Def->uses()) {
3606 if (auto *I = dyn_cast<Instruction>(U.getUser())) {
3607 // Don't try to replace into dead uses
3608 if (InstructionsToErase.count(I))
3609 continue;
3610 ValueDFS VDUse;
3611 // Put the phi node uses in the incoming block.
3612 BasicBlock *IBlock;
3613 if (auto *P = dyn_cast<PHINode>(I)) {
3614 IBlock = P->getIncomingBlock(U);
3615 // Make phi node users appear last in the incoming block
3616 // they are from.
3617 VDUse.LocalNum = InstrDFS.size() + 1;
3618 } else {
3619 IBlock = getBlockForValue(I);
3620 VDUse.LocalNum = InstrToDFSNum(I);
3621 }
3622
3623 // Skip uses in unreachable blocks, as we're going
3624 // to delete them.
3625 if (ReachableBlocks.count(IBlock) == 0)
3626 continue;
3627
3628 DomTreeNode *DomNode = DT->getNode(IBlock);
3629 VDUse.DFSIn = DomNode->getDFSNumIn();
3630 VDUse.DFSOut = DomNode->getDFSNumOut();
3631 VDUse.U = &U;
3632 ++UseCount;
3633 DFSOrderedSet.emplace_back(VDUse);
3634 }
3635 }
3636
3637 // If there are no uses, it's probably dead (but it may have side-effects,
3638 // so not definitely dead. Otherwise, store the number of uses so we can
3639 // track if it becomes dead later).
3640 if (UseCount == 0)
3641 ProbablyDead.insert(Def);
3642 else
3643 UseCounts[Def] = UseCount;
3644 }
3645}
3646
3647// This function converts the set of members for a congruence class from values,
3648// to the set of defs for loads and stores, with associated DFS info.
3649void NewGVN::convertClassToLoadsAndStores(
3650 const CongruenceClass &Dense,
3651 SmallVectorImpl<ValueDFS> &LoadsAndStores) const {
3652 for (auto D : Dense) {
3653 if (!isa<LoadInst>(D) && !isa<StoreInst>(D))
3654 continue;
3655
3656 BasicBlock *BB = getBlockForValue(D);
3657 ValueDFS VD;
3658 DomTreeNode *DomNode = DT->getNode(BB);
3659 VD.DFSIn = DomNode->getDFSNumIn();
3660 VD.DFSOut = DomNode->getDFSNumOut();
3661 VD.Def.setPointer(D);
3662
3663 // If it's an instruction, use the real local dfs number.
3664 if (auto *I = dyn_cast<Instruction>(D))
3665 VD.LocalNum = InstrToDFSNum(I);
3666 else
3667 llvm_unreachable("Should have been an instruction")::llvm::llvm_unreachable_internal("Should have been an instruction"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3667)
;
3668
3669 LoadsAndStores.emplace_back(VD);
3670 }
3671}
3672
3673static void patchAndReplaceAllUsesWith(Instruction *I, Value *Repl) {
3674 patchReplacementInstruction(I, Repl);
3675 I->replaceAllUsesWith(Repl);
3676}
3677
3678void NewGVN::deleteInstructionsInBlock(BasicBlock *BB) {
3679 LLVM_DEBUG(dbgs() << " BasicBlock Dead:" << *BB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " BasicBlock Dead:" << *
BB; } } while (false)
;
3680 ++NumGVNBlocksDeleted;
3681
3682 // Delete the instructions backwards, as it has a reduced likelihood of having
3683 // to update as many def-use and use-def chains. Start after the terminator.
3684 auto StartPoint = BB->rbegin();
3685 ++StartPoint;
3686 // Note that we explicitly recalculate BB->rend() on each iteration,
3687 // as it may change when we remove the first instruction.
3688 for (BasicBlock::reverse_iterator I(StartPoint); I != BB->rend();) {
3689 Instruction &Inst = *I++;
3690 if (!Inst.use_empty())
3691 Inst.replaceAllUsesWith(UndefValue::get(Inst.getType()));
3692 if (isa<LandingPadInst>(Inst))
3693 continue;
3694
3695 Inst.eraseFromParent();
3696 ++NumGVNInstrDeleted;
3697 }
3698 // Now insert something that simplifycfg will turn into an unreachable.
3699 Type *Int8Ty = Type::getInt8Ty(BB->getContext());
3700 new StoreInst(UndefValue::get(Int8Ty),
3701 Constant::getNullValue(Int8Ty->getPointerTo()),
3702 BB->getTerminator());
3703}
3704
3705void NewGVN::markInstructionForDeletion(Instruction *I) {
3706 LLVM_DEBUG(dbgs() << "Marking " << *I << " for deletion\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Marking " << *I <<
" for deletion\n"; } } while (false)
;
3707 InstructionsToErase.insert(I);
3708}
3709
3710void NewGVN::replaceInstruction(Instruction *I, Value *V) {
3711 LLVM_DEBUG(dbgs() << "Replacing " << *I << " with " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing " << *I <<
" with " << *V << "\n"; } } while (false)
;
3712 patchAndReplaceAllUsesWith(I, V);
3713 // We save the actual erasing to avoid invalidating memory
3714 // dependencies until we are done with everything.
3715 markInstructionForDeletion(I);
3716}
3717
3718namespace {
3719
3720// This is a stack that contains both the value and dfs info of where
3721// that value is valid.
3722class ValueDFSStack {
3723public:
3724 Value *back() const { return ValueStack.back(); }
3725 std::pair<int, int> dfs_back() const { return DFSStack.back(); }
3726
3727 void push_back(Value *V, int DFSIn, int DFSOut) {
3728 ValueStack.emplace_back(V);
3729 DFSStack.emplace_back(DFSIn, DFSOut);
3730 }
3731
3732 bool empty() const { return DFSStack.empty(); }
3733
3734 bool isInScope(int DFSIn, int DFSOut) const {
3735 if (empty())
3736 return false;
3737 return DFSIn >= DFSStack.back().first && DFSOut <= DFSStack.back().second;
3738 }
3739
3740 void popUntilDFSScope(int DFSIn, int DFSOut) {
3741
3742 // These two should always be in sync at this point.
3743 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3744, __PRETTY_FUNCTION__))
3744 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3744, __PRETTY_FUNCTION__))
;
3745 while (
3746 !DFSStack.empty() &&
3747 !(DFSIn >= DFSStack.back().first && DFSOut <= DFSStack.back().second)) {
3748 DFSStack.pop_back();
3749 ValueStack.pop_back();
3750 }
3751 }
3752
3753private:
3754 SmallVector<Value *, 8> ValueStack;
3755 SmallVector<std::pair<int, int>, 8> DFSStack;
3756};
3757
3758} // end anonymous namespace
3759
3760// Given an expression, get the congruence class for it.
3761CongruenceClass *NewGVN::getClassForExpression(const Expression *E) const {
3762 if (auto *VE = dyn_cast<VariableExpression>(E))
3763 return ValueToClass.lookup(VE->getVariableValue());
3764 else if (isa<DeadExpression>(E))
3765 return TOPClass;
3766 return ExpressionToClass.lookup(E);
3767}
3768
3769// Given a value and a basic block we are trying to see if it is available in,
3770// see if the value has a leader available in that block.
3771Value *NewGVN::findPHIOfOpsLeader(const Expression *E,
3772 const Instruction *OrigInst,
3773 const BasicBlock *BB) const {
3774 // It would already be constant if we could make it constant
3775 if (auto *CE = dyn_cast<ConstantExpression>(E))
3776 return CE->getConstantValue();
3777 if (auto *VE = dyn_cast<VariableExpression>(E)) {
3778 auto *V = VE->getVariableValue();
3779 if (alwaysAvailable(V) || DT->dominates(getBlockForValue(V), BB))
3780 return VE->getVariableValue();
3781 }
3782
3783 auto *CC = getClassForExpression(E);
3784 if (!CC)
3785 return nullptr;
3786 if (alwaysAvailable(CC->getLeader()))
3787 return CC->getLeader();
3788
3789 for (auto Member : *CC) {
3790 auto *MemberInst = dyn_cast<Instruction>(Member);
3791 if (MemberInst == OrigInst)
3792 continue;
3793 // Anything that isn't an instruction is always available.
3794 if (!MemberInst)
3795 return Member;
3796 if (DT->dominates(getBlockForValue(MemberInst), BB))
3797 return Member;
3798 }
3799 return nullptr;
3800}
3801
3802bool NewGVN::eliminateInstructions(Function &F) {
3803 // This is a non-standard eliminator. The normal way to eliminate is
3804 // to walk the dominator tree in order, keeping track of available
3805 // values, and eliminating them. However, this is mildly
3806 // pointless. It requires doing lookups on every instruction,
3807 // regardless of whether we will ever eliminate it. For
3808 // instructions part of most singleton congruence classes, we know we
3809 // will never eliminate them.
3810
3811 // Instead, this eliminator looks at the congruence classes directly, sorts
3812 // them into a DFS ordering of the dominator tree, and then we just
3813 // perform elimination straight on the sets by walking the congruence
3814 // class member uses in order, and eliminate the ones dominated by the
3815 // last member. This is worst case O(E log E) where E = number of
3816 // instructions in a single congruence class. In theory, this is all
3817 // instructions. In practice, it is much faster, as most instructions are
3818 // either in singleton congruence classes or can't possibly be eliminated
3819 // anyway (if there are no overlapping DFS ranges in class).
3820 // When we find something not dominated, it becomes the new leader
3821 // for elimination purposes.
3822 // TODO: If we wanted to be faster, We could remove any members with no
3823 // overlapping ranges while sorting, as we will never eliminate anything
3824 // with those members, as they don't dominate anything else in our set.
3825
3826 bool AnythingReplaced = false;
3827
3828 // Since we are going to walk the domtree anyway, and we can't guarantee the
3829 // DFS numbers are updated, we compute some ourselves.
3830 DT->updateDFSNumbers();
3831
3832 // Go through all of our phi nodes, and kill the arguments associated with
3833 // unreachable edges.
3834 auto ReplaceUnreachablePHIArgs = [&](PHINode *PHI, BasicBlock *BB) {
3835 for (auto &Operand : PHI->incoming_values())
3836 if (!ReachableEdges.count({PHI->getIncomingBlock(Operand), BB})) {
3837 LLVM_DEBUG(dbgs() << "Replacing incoming value of " << PHIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing incoming value of " <<
PHI << " for block " << getBlockName(PHI->getIncomingBlock
(Operand)) << " with undef due to it being unreachable\n"
; } } while (false)
3838 << " for block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing incoming value of " <<
PHI << " for block " << getBlockName(PHI->getIncomingBlock
(Operand)) << " with undef due to it being unreachable\n"
; } } while (false)
3839 << getBlockName(PHI->getIncomingBlock(Operand))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing incoming value of " <<
PHI << " for block " << getBlockName(PHI->getIncomingBlock
(Operand)) << " with undef due to it being unreachable\n"
; } } while (false)
3840 << " with undef due to it being unreachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing incoming value of " <<
PHI << " for block " << getBlockName(PHI->getIncomingBlock
(Operand)) << " with undef due to it being unreachable\n"
; } } while (false)
;
3841 Operand.set(UndefValue::get(PHI->getType()));
3842 }
3843 };
3844 // Replace unreachable phi arguments.
3845 // At this point, RevisitOnReachabilityChange only contains:
3846 //
3847 // 1. PHIs
3848 // 2. Temporaries that will convert to PHIs
3849 // 3. Operations that are affected by an unreachable edge but do not fit into
3850 // 1 or 2 (rare).
3851 // So it is a slight overshoot of what we want. We could make it exact by
3852 // using two SparseBitVectors per block.
3853 DenseMap<const BasicBlock *, unsigned> ReachablePredCount;
3854 for (auto &KV : ReachableEdges)
3855 ReachablePredCount[KV.getEnd()]++;
3856 for (auto &BBPair : RevisitOnReachabilityChange) {
3857 for (auto InstNum : BBPair.second) {
3858 auto *Inst = InstrFromDFSNum(InstNum);
3859 auto *PHI = dyn_cast<PHINode>(Inst);
3860 PHI = PHI ? PHI : dyn_cast_or_null<PHINode>(RealToTemp.lookup(Inst));
3861 if (!PHI)
3862 continue;
3863 auto *BB = BBPair.first;
3864 if (ReachablePredCount.lookup(BB) != PHI->getNumIncomingValues())
3865 ReplaceUnreachablePHIArgs(PHI, BB);
3866 }
3867 }
3868
3869 // Map to store the use counts
3870 DenseMap<const Value *, unsigned int> UseCounts;
3871 for (auto *CC : reverse(CongruenceClasses)) {
3872 LLVM_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)
3873 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Eliminating in congruence class "
<< CC->getID() << "\n"; } } while (false)
;
3874 // Track the equivalent store info so we can decide whether to try
3875 // dead store elimination.
3876 SmallVector<ValueDFS, 8> PossibleDeadStores;
3877 SmallPtrSet<Instruction *, 8> ProbablyDead;
3878 if (CC->isDead() || CC->empty())
3879 continue;
3880 // Everything still in the TOP class is unreachable or dead.
3881 if (CC == TOPClass) {
3882 for (auto M : *CC) {
3883 auto *VTE = ValueToExpression.lookup(M);
3884 if (VTE && isa<DeadExpression>(VTE))
3885 markInstructionForDeletion(cast<Instruction>(M));
3886 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3889, __PRETTY_FUNCTION__))
3887 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3889, __PRETTY_FUNCTION__))
3888 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3889, __PRETTY_FUNCTION__))
3889 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3889, __PRETTY_FUNCTION__))
;
3890 }
3891 continue;
3892 }
3893
3894 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3894, __PRETTY_FUNCTION__))
;
3895 // If this is a leader that is always available, and it's a
3896 // constant or has no equivalences, just replace everything with
3897 // it. We then update the congruence class with whatever members
3898 // are left.
3899 Value *Leader =
3900 CC->getStoredValue() ? CC->getStoredValue() : CC->getLeader();
3901 if (alwaysAvailable(Leader)) {
3902 CongruenceClass::MemberSet MembersLeft;
3903 for (auto M : *CC) {
3904 Value *Member = M;
3905 // Void things have no uses we can replace.
3906 if (Member == Leader || !isa<Instruction>(Member) ||
3907 Member->getType()->isVoidTy()) {
3908 MembersLeft.insert(Member);
3909 continue;
3910 }
3911 LLVM_DEBUG(dbgs() << "Found replacement " << *(Leader) << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
(Leader) << " for " << *Member << "\n"; } }
while (false)
3912 << *Member << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
(Leader) << " for " << *Member << "\n"; } }
while (false)
;
3913 auto *I = cast<Instruction>(Member);
3914 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 3914, __PRETTY_FUNCTION__))
;
3915 replaceInstruction(I, Leader);
3916 AnythingReplaced = true;
3917 }
3918 CC->swap(MembersLeft);
3919 } else {
3920 // If this is a singleton, we can skip it.
3921 if (CC->size() != 1 || RealToTemp.count(Leader)) {
3922 // This is a stack because equality replacement/etc may place
3923 // constants in the middle of the member list, and we want to use
3924 // those constant values in preference to the current leader, over
3925 // the scope of those constants.
3926 ValueDFSStack EliminationStack;
3927
3928 // Convert the members to DFS ordered sets and then merge them.
3929 SmallVector<ValueDFS, 8> DFSOrderedSet;
3930 convertClassToDFSOrdered(*CC, DFSOrderedSet, UseCounts, ProbablyDead);
3931
3932 // Sort the whole thing.
3933 llvm::sort(DFSOrderedSet);
3934 for (auto &VD : DFSOrderedSet) {
3935 int MemberDFSIn = VD.DFSIn;
3936 int MemberDFSOut = VD.DFSOut;
3937 Value *Def = VD.Def.getPointer();
3938 bool FromStore = VD.Def.getInt();
3939 Use *U = VD.U;
3940 // We ignore void things because we can't get a value from them.
3941 if (Def && Def->getType()->isVoidTy())
3942 continue;
3943 auto *DefInst = dyn_cast_or_null<Instruction>(Def);
3944 if (DefInst && AllTempInstructions.count(DefInst)) {
3945 auto *PN = cast<PHINode>(DefInst);
3946
3947 // If this is a value phi and that's the expression we used, insert
3948 // it into the program
3949 // remove from temp instruction list.
3950 AllTempInstructions.erase(PN);
3951 auto *DefBlock = getBlockForValue(Def);
3952 LLVM_DEBUG(dbgs() << "Inserting fully real phi of ops" << *Defdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Inserting fully real phi of ops"
<< *Def << " into block " << getBlockName(
getBlockForValue(Def)) << "\n"; } } while (false)
3953 << " into block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Inserting fully real phi of ops"
<< *Def << " into block " << getBlockName(
getBlockForValue(Def)) << "\n"; } } while (false)
3954 << getBlockName(getBlockForValue(Def)) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Inserting fully real phi of ops"
<< *Def << " into block " << getBlockName(
getBlockForValue(Def)) << "\n"; } } while (false)
;
3955 PN->insertBefore(&DefBlock->front());
3956 Def = PN;
3957 NumGVNPHIOfOpsEliminations++;
3958 }
3959
3960 if (EliminationStack.empty()) {
3961 LLVM_DEBUG(dbgs() << "Elimination Stack is empty\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Elimination Stack is empty\n";
} } while (false)
;
3962 } else {
3963 LLVM_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)
3964 << 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)
3965 << 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)
;
3966 }
3967
3968 LLVM_DEBUG(dbgs() << "Current DFS numbers are (" << MemberDFSIn << ","do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Current DFS numbers are (" <<
MemberDFSIn << "," << MemberDFSOut << ")\n"
; } } while (false)
3969 << MemberDFSOut << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Current DFS numbers are (" <<
MemberDFSIn << "," << MemberDFSOut << ")\n"
; } } while (false)
;
3970 // First, we see if we are out of scope or empty. If so,
3971 // and there equivalences, we try to replace the top of
3972 // stack with equivalences (if it's on the stack, it must
3973 // not have been eliminated yet).
3974 // Then we synchronize to our current scope, by
3975 // popping until we are back within a DFS scope that
3976 // dominates the current member.
3977 // Then, what happens depends on a few factors
3978 // If the stack is now empty, we need to push
3979 // If we have a constant or a local equivalence we want to
3980 // start using, we also push.
3981 // Otherwise, we walk along, processing members who are
3982 // dominated by this scope, and eliminate them.
3983 bool ShouldPush = Def && EliminationStack.empty();
3984 bool OutOfScope =
3985 !EliminationStack.isInScope(MemberDFSIn, MemberDFSOut);
3986
3987 if (OutOfScope || ShouldPush) {
3988 // Sync to our current scope.
3989 EliminationStack.popUntilDFSScope(MemberDFSIn, MemberDFSOut);
3990 bool ShouldPush = Def && EliminationStack.empty();
3991 if (ShouldPush) {
3992 EliminationStack.push_back(Def, MemberDFSIn, MemberDFSOut);
3993 }
3994 }
3995
3996 // Skip the Def's, we only want to eliminate on their uses. But mark
3997 // dominated defs as dead.
3998 if (Def) {
3999 // For anything in this case, what and how we value number
4000 // guarantees that any side-effets that would have occurred (ie
4001 // throwing, etc) can be proven to either still occur (because it's
4002 // dominated by something that has the same side-effects), or never
4003 // occur. Otherwise, we would not have been able to prove it value
4004 // equivalent to something else. For these things, we can just mark
4005 // it all dead. Note that this is different from the "ProbablyDead"
4006 // set, which may not be dominated by anything, and thus, are only
4007 // easy to prove dead if they are also side-effect free. Note that
4008 // because stores are put in terms of the stored value, we skip
4009 // stored values here. If the stored value is really dead, it will
4010 // still be marked for deletion when we process it in its own class.
4011 if (!EliminationStack.empty() && Def != EliminationStack.back() &&
4012 isa<Instruction>(Def) && !FromStore)
4013 markInstructionForDeletion(cast<Instruction>(Def));
4014 continue;
4015 }
4016 // At this point, we know it is a Use we are trying to possibly
4017 // replace.
4018
4019 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 4020, __PRETTY_FUNCTION__))
4020 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 4020, __PRETTY_FUNCTION__))
;
4021 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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 4022, __PRETTY_FUNCTION__))
4022 "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\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 4022, __PRETTY_FUNCTION__))
;
4023
4024 // If the thing we are replacing into is already marked to be dead,
4025 // this use is dead. Note that this is true regardless of whether
4026 // we have anything dominating the use or not. We do this here
4027 // because we are already walking all the uses anyway.
4028 Instruction *InstUse = cast<Instruction>(U->getUser());
4029 if (InstructionsToErase.count(InstUse)) {
4030 auto &UseCount = UseCounts[U->get()];
4031 if (--UseCount == 0) {
4032 ProbablyDead.insert(cast<Instruction>(U->get()));
4033 }
4034 }
4035
4036 // If we get to this point, and the stack is empty we must have a use
4037 // with nothing we can use to eliminate this use, so just skip it.
4038 if (EliminationStack.empty())
4039 continue;
4040
4041 Value *DominatingLeader = EliminationStack.back();
4042
4043 auto *II = dyn_cast<IntrinsicInst>(DominatingLeader);
4044 bool isSSACopy = II && II->getIntrinsicID() == Intrinsic::ssa_copy;
4045 if (isSSACopy)
4046 DominatingLeader = II->getOperand(0);
4047
4048 // Don't replace our existing users with ourselves.
4049 if (U->get() == DominatingLeader)
4050 continue;
4051 LLVM_DEBUG(dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
DominatingLeader << " for " << *U->get() <<
" in " << *(U->getUser()) << "\n"; } } while (
false)
4052 << "Found replacement " << *DominatingLeader << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
DominatingLeader << " for " << *U->get() <<
" in " << *(U->getUser()) << "\n"; } } while (
false)
4053 << *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)
;
4054
4055 // If we replaced something in an instruction, handle the patching of
4056 // metadata. Skip this if we are replacing predicateinfo with its
4057 // original operand, as we already know we can just drop it.
4058 auto *ReplacedInst = cast<Instruction>(U->get());
4059 auto *PI = PredInfo->getPredicateInfoFor(ReplacedInst);
4060 if (!PI || DominatingLeader != PI->OriginalOp)
4061 patchReplacementInstruction(ReplacedInst, DominatingLeader);
4062 U->set(DominatingLeader);
4063 // This is now a use of the dominating leader, which means if the
4064 // dominating leader was dead, it's now live!
4065 auto &LeaderUseCount = UseCounts[DominatingLeader];
4066 // It's about to be alive again.
4067 if (LeaderUseCount == 0 && isa<Instruction>(DominatingLeader))
4068 ProbablyDead.erase(cast<Instruction>(DominatingLeader));
4069 // For copy instructions, we use their operand as a leader,
4070 // which means we remove a user of the copy and it may become dead.
4071 if (isSSACopy) {
4072 unsigned &IIUseCount = UseCounts[II];
4073 if (--IIUseCount == 0)
4074 ProbablyDead.insert(II);
4075 }
4076 ++LeaderUseCount;
4077 AnythingReplaced = true;
4078 }
4079 }
4080 }
4081
4082 // At this point, anything still in the ProbablyDead set is actually dead if
4083 // would be trivially dead.
4084 for (auto *I : ProbablyDead)
4085 if (wouldInstructionBeTriviallyDead(I))
4086 markInstructionForDeletion(I);
4087
4088 // Cleanup the congruence class.
4089 CongruenceClass::MemberSet MembersLeft;
4090 for (auto *Member : *CC)
4091 if (!isa<Instruction>(Member) ||
4092 !InstructionsToErase.count(cast<Instruction>(Member)))
4093 MembersLeft.insert(Member);
4094 CC->swap(MembersLeft);
4095
4096 // If we have possible dead stores to look at, try to eliminate them.
4097 if (CC->getStoreCount() > 0) {
4098 convertClassToLoadsAndStores(*CC, PossibleDeadStores);
4099 llvm::sort(PossibleDeadStores);
4100 ValueDFSStack EliminationStack;
4101 for (auto &VD : PossibleDeadStores) {
4102 int MemberDFSIn = VD.DFSIn;
4103 int MemberDFSOut = VD.DFSOut;
4104 Instruction *Member = cast<Instruction>(VD.Def.getPointer());
4105 if (EliminationStack.empty() ||
4106 !EliminationStack.isInScope(MemberDFSIn, MemberDFSOut)) {
4107 // Sync to our current scope.
4108 EliminationStack.popUntilDFSScope(MemberDFSIn, MemberDFSOut);
4109 if (EliminationStack.empty()) {
4110 EliminationStack.push_back(Member, MemberDFSIn, MemberDFSOut);
4111 continue;
4112 }
4113 }
4114 // We already did load elimination, so nothing to do here.
4115 if (isa<LoadInst>(Member))
4116 continue;
4117 assert(!EliminationStack.empty())((!EliminationStack.empty()) ? static_cast<void> (0) : __assert_fail
("!EliminationStack.empty()", "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 4117, __PRETTY_FUNCTION__))
;
4118 Instruction *Leader = cast<Instruction>(EliminationStack.back());
4119 (void)Leader;
4120 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())"
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/Transforms/Scalar/NewGVN.cpp"
, 4120, __PRETTY_FUNCTION__))
;
4121 // Member is dominater by Leader, and thus dead
4122 LLVM_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)
4123 << " 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)
;
4124 markInstructionForDeletion(Member);
4125 CC->erase(Member);
4126 ++NumGVNDeadStores;
4127 }
4128 }
4129 }
4130 return AnythingReplaced;
4131}
4132
4133// This function provides global ranking of operations so that we can place them
4134// in a canonical order. Note that rank alone is not necessarily enough for a
4135// complete ordering, as constants all have the same rank. However, generally,
4136// we will simplify an operation with all constants so that it doesn't matter
4137// what order they appear in.
4138unsigned int NewGVN::getRank(const Value *V) const {
4139 // Prefer constants to undef to anything else
4140 // Undef is a constant, have to check it first.
4141 // Prefer smaller constants to constantexprs
4142 if (isa<ConstantExpr>(V))
4143 return 2;
4144 if (isa<UndefValue>(V))
4145 return 1;
4146 if (isa<Constant>(V))
4147 return 0;
4148 else if (auto *A = dyn_cast<Argument>(V))
4149 return 3 + A->getArgNo();
4150
4151 // Need to shift the instruction DFS by number of arguments + 3 to account for
4152 // the constant and argument ranking above.
4153 unsigned Result = InstrToDFSNum(V);
4154 if (Result > 0)
4155 return 4 + NumFuncArgs + Result;
4156 // Unreachable or something else, just return a really large number.
4157 return ~0;
4158}
4159
4160// This is a function that says whether two commutative operations should
4161// have their order swapped when canonicalizing.
4162bool NewGVN::shouldSwapOperands(const Value *A, const Value *B) const {
4163 // Because we only care about a total ordering, and don't rewrite expressions
4164 // in this order, we order by rank, which will give a strict weak ordering to
4165 // everything but constants, and then we order by pointer address.
4166 return std::make_pair(getRank(A), A) > std::make_pair(getRank(B), B);
4167}
4168
4169namespace {
4170
4171class NewGVNLegacyPass : public FunctionPass {
4172public:
4173 // Pass identification, replacement for typeid.
4174 static char ID;
4175
4176 NewGVNLegacyPass() : FunctionPass(ID) {
4177 initializeNewGVNLegacyPassPass(*PassRegistry::getPassRegistry());
4178 }
4179
4180 bool runOnFunction(Function &F) override;
4181
4182private:
4183 void getAnalysisUsage(AnalysisUsage &AU) const override {
4184 AU.addRequired<AssumptionCacheTracker>();
4185 AU.addRequired<DominatorTreeWrapperPass>();
4186 AU.addRequired<TargetLibraryInfoWrapperPass>();
4187 AU.addRequired<MemorySSAWrapperPass>();
4188 AU.addRequired<AAResultsWrapperPass>();
4189 AU.addPreserved<DominatorTreeWrapperPass>();
4190 AU.addPreserved<GlobalsAAWrapperPass>();
4191 }
4192};
4193
4194} // end anonymous namespace
4195
4196bool NewGVNLegacyPass::runOnFunction(Function &F) {
4197 if (skipFunction(F))
4198 return false;
4199 return NewGVN(F, &getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
4200 &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F),
4201 &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(),
4202 &getAnalysis<AAResultsWrapperPass>().getAAResults(),
4203 &getAnalysis<MemorySSAWrapperPass>().getMSSA(),
4204 F.getParent()->getDataLayout())
4205 .runGVN();
4206}
4207
4208char NewGVNLegacyPass::ID = 0;
4209
4210INITIALIZE_PASS_BEGIN(NewGVNLegacyPass, "newgvn", "Global Value Numbering",static void *initializeNewGVNLegacyPassPassOnce(PassRegistry &
Registry) {
4211 false, false)static void *initializeNewGVNLegacyPassPassOnce(PassRegistry &
Registry) {
4212INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
4213INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
4214INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
4215INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
4216INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
4217INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)initializeGlobalsAAWrapperPassPass(Registry);
4218INITIALIZE_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)); }
4219 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)); }
4220
4221// createGVNPass - The public interface to this file.
4222FunctionPass *llvm::createNewGVNPass() { return new NewGVNLegacyPass(); }
4223
4224PreservedAnalyses NewGVNPass::run(Function &F, AnalysisManager<Function> &AM) {
4225 // Apparently the order in which we get these results matter for
4226 // the old GVN (see Chandler's comment in GVN.cpp). I'll keep
4227 // the same order here, just in case.
4228 auto &AC = AM.getResult<AssumptionAnalysis>(F);
4229 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
4230 auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
4231 auto &AA = AM.getResult<AAManager>(F);
4232 auto &MSSA = AM.getResult<MemorySSAAnalysis>(F).getMSSA();
4233 bool Changed =
4234 NewGVN(F, &DT, &AC, &TLI, &AA, &MSSA, F.getParent()->getDataLayout())
4235 .runGVN();
4236 if (!Changed)
4237 return PreservedAnalyses::all();
4238 PreservedAnalyses PA;
4239 PA.preserve<DominatorTreeAnalysis>();
4240 PA.preserve<GlobalsAA>();
4241 return PA;
4242}