Bug Summary

File:lib/Transforms/Scalar/NewGVN.cpp
Warning:line 988, column 3
Called C++ object pointer is null

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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 -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/lib/Transforms/Scalar -I /build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn345461/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/lib/Transforms/Scalar -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-10-27-211344-32123-1 -x c++ /build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp -faddrsig
1//===- NewGVN.cpp - Global Value Numbering Pass ---------------------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10/// \file
11/// This file implements the new LLVM's Global Value Numbering pass.
12/// GVN partitions values computed by a function into congruence classes.
13/// Values ending up in the same congruence class are guaranteed to be the same
14/// for every execution of the program. In that respect, congruency is a
15/// compile-time approximation of equivalence of values at runtime.
16/// The algorithm implemented here uses a sparse formulation and it's based
17/// on the ideas described in the paper:
18/// "A Sparse Algorithm for Predicated Global Value Numbering" from
19/// Karthik Gargi.
20///
21/// A brief overview of the algorithm: The algorithm is essentially the same as
22/// the standard RPO value numbering algorithm (a good reference is the paper
23/// "SCC based value numbering" by L. Taylor Simpson) with one major difference:
24/// The RPO algorithm proceeds, on every iteration, to process every reachable
25/// block and every instruction in that block. This is because the standard RPO
26/// algorithm does not track what things have the same value number, it only
27/// tracks what the value number of a given operation is (the mapping is
28/// operation -> value number). Thus, when a value number of an operation
29/// changes, it must reprocess everything to ensure all uses of a value number
30/// get updated properly. In constrast, the sparse algorithm we use *also*
31/// tracks what operations have a given value number (IE it also tracks the
32/// reverse mapping from value number -> operations with that value number), so
33/// that it only needs to reprocess the instructions that are affected when
34/// something's value number changes. The vast majority of complexity and code
35/// in this file is devoted to tracking what value numbers could change for what
36/// instructions when various things happen. The rest of the algorithm is
37/// devoted to performing symbolic evaluation, forward propagation, and
38/// simplification of operations based on the value numbers deduced so far
39///
40/// In order to make the GVN mostly-complete, we use a technique derived from
41/// "Detection of Redundant Expressions: A Complete and Polynomial-time
42/// Algorithm in SSA" by R.R. Pai. The source of incompleteness in most SSA
43/// based GVN algorithms is related to their inability to detect equivalence
44/// between phi of ops (IE phi(a+b, c+d)) and op of phis (phi(a,c) + phi(b, d)).
45/// We resolve this issue by generating the equivalent "phi of ops" form for
46/// each op of phis we see, in a way that only takes polynomial time to resolve.
47///
48/// We also do not perform elimination by using any published algorithm. All
49/// published algorithms are O(Instructions). Instead, we use a technique that
50/// is O(number of operations with the same value number), enabling us to skip
51/// trying to eliminate things that have unique value numbers.
52//
53//===----------------------------------------------------------------------===//
54
55#include "llvm/Transforms/Scalar/NewGVN.h"
56#include "llvm/ADT/ArrayRef.h"
57#include "llvm/ADT/BitVector.h"
58#include "llvm/ADT/DenseMap.h"
59#include "llvm/ADT/DenseMapInfo.h"
60#include "llvm/ADT/DenseSet.h"
61#include "llvm/ADT/DepthFirstIterator.h"
62#include "llvm/ADT/GraphTraits.h"
63#include "llvm/ADT/Hashing.h"
64#include "llvm/ADT/PointerIntPair.h"
65#include "llvm/ADT/PostOrderIterator.h"
66#include "llvm/ADT/SmallPtrSet.h"
67#include "llvm/ADT/SmallVector.h"
68#include "llvm/ADT/SparseBitVector.h"
69#include "llvm/ADT/Statistic.h"
70#include "llvm/ADT/iterator_range.h"
71#include "llvm/Analysis/AliasAnalysis.h"
72#include "llvm/Analysis/AssumptionCache.h"
73#include "llvm/Analysis/CFGPrinter.h"
74#include "llvm/Analysis/ConstantFolding.h"
75#include "llvm/Analysis/GlobalsModRef.h"
76#include "llvm/Analysis/InstructionSimplify.h"
77#include "llvm/Analysis/MemoryBuiltins.h"
78#include "llvm/Analysis/MemorySSA.h"
79#include "llvm/Analysis/TargetLibraryInfo.h"
80#include "llvm/Transforms/Utils/Local.h"
81#include "llvm/IR/Argument.h"
82#include "llvm/IR/BasicBlock.h"
83#include "llvm/IR/Constant.h"
84#include "llvm/IR/Constants.h"
85#include "llvm/IR/Dominators.h"
86#include "llvm/IR/Function.h"
87#include "llvm/IR/InstrTypes.h"
88#include "llvm/IR/Instruction.h"
89#include "llvm/IR/Instructions.h"
90#include "llvm/IR/IntrinsicInst.h"
91#include "llvm/IR/Intrinsics.h"
92#include "llvm/IR/LLVMContext.h"
93#include "llvm/IR/Type.h"
94#include "llvm/IR/Use.h"
95#include "llvm/IR/User.h"
96#include "llvm/IR/Value.h"
97#include "llvm/Pass.h"
98#include "llvm/Support/Allocator.h"
99#include "llvm/Support/ArrayRecycler.h"
100#include "llvm/Support/Casting.h"
101#include "llvm/Support/CommandLine.h"
102#include "llvm/Support/Debug.h"
103#include "llvm/Support/DebugCounter.h"
104#include "llvm/Support/ErrorHandling.h"
105#include "llvm/Support/PointerLikeTypeTraits.h"
106#include "llvm/Support/raw_ostream.h"
107#include "llvm/Transforms/Scalar.h"
108#include "llvm/Transforms/Scalar/GVNExpression.h"
109#include "llvm/Transforms/Utils/PredicateInfo.h"
110#include "llvm/Transforms/Utils/VNCoercion.h"
111#include <algorithm>
112#include <cassert>
113#include <cstdint>
114#include <iterator>
115#include <map>
116#include <memory>
117#include <set>
118#include <string>
119#include <tuple>
120#include <utility>
121#include <vector>
122
123using namespace llvm;
124using namespace llvm::GVNExpression;
125using namespace llvm::VNCoercion;
126
127#define DEBUG_TYPE"newgvn" "newgvn"
128
129STATISTIC(NumGVNInstrDeleted, "Number of instructions deleted")static llvm::Statistic NumGVNInstrDeleted = {"newgvn", "NumGVNInstrDeleted"
, "Number of instructions deleted", {0}, {false}}
;
130STATISTIC(NumGVNBlocksDeleted, "Number of blocks deleted")static llvm::Statistic NumGVNBlocksDeleted = {"newgvn", "NumGVNBlocksDeleted"
, "Number of blocks deleted", {0}, {false}}
;
131STATISTIC(NumGVNOpsSimplified, "Number of Expressions simplified")static llvm::Statistic NumGVNOpsSimplified = {"newgvn", "NumGVNOpsSimplified"
, "Number of Expressions simplified", {0}, {false}}
;
132STATISTIC(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
}}
;
133STATISTIC(NumGVNMaxIterations,static llvm::Statistic NumGVNMaxIterations = {"newgvn", "NumGVNMaxIterations"
, "Maximum Number of iterations it took to converge GVN", {0}
, {false}}
134 "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}}
;
135STATISTIC(NumGVNLeaderChanges, "Number of leader changes")static llvm::Statistic NumGVNLeaderChanges = {"newgvn", "NumGVNLeaderChanges"
, "Number of leader changes", {0}, {false}}
;
136STATISTIC(NumGVNSortedLeaderChanges, "Number of sorted leader changes")static llvm::Statistic NumGVNSortedLeaderChanges = {"newgvn",
"NumGVNSortedLeaderChanges", "Number of sorted leader changes"
, {0}, {false}}
;
137STATISTIC(NumGVNAvoidedSortedLeaderChanges,static llvm::Statistic NumGVNAvoidedSortedLeaderChanges = {"newgvn"
, "NumGVNAvoidedSortedLeaderChanges", "Number of avoided sorted leader changes"
, {0}, {false}}
138 "Number of avoided sorted leader changes")static llvm::Statistic NumGVNAvoidedSortedLeaderChanges = {"newgvn"
, "NumGVNAvoidedSortedLeaderChanges", "Number of avoided sorted leader changes"
, {0}, {false}}
;
139STATISTIC(NumGVNDeadStores, "Number of redundant/dead stores eliminated")static llvm::Statistic NumGVNDeadStores = {"newgvn", "NumGVNDeadStores"
, "Number of redundant/dead stores eliminated", {0}, {false}}
;
140STATISTIC(NumGVNPHIOfOpsCreated, "Number of PHI of ops created")static llvm::Statistic NumGVNPHIOfOpsCreated = {"newgvn", "NumGVNPHIOfOpsCreated"
, "Number of PHI of ops created", {0}, {false}}
;
141STATISTIC(NumGVNPHIOfOpsEliminations,static llvm::Statistic NumGVNPHIOfOpsEliminations = {"newgvn"
, "NumGVNPHIOfOpsEliminations", "Number of things eliminated using PHI of ops"
, {0}, {false}}
142 "Number of things eliminated using PHI of ops")static llvm::Statistic NumGVNPHIOfOpsEliminations = {"newgvn"
, "NumGVNPHIOfOpsEliminations", "Number of things eliminated using PHI of ops"
, {0}, {false}}
;
143DEBUG_COUNTER(VNCounter, "newgvn-vn",static const unsigned VNCounter = DebugCounter::registerCounter
("newgvn-vn", "Controls which instructions are value numbered"
)
144 "Controls which instructions are value numbered")static const unsigned VNCounter = DebugCounter::registerCounter
("newgvn-vn", "Controls which instructions are value numbered"
)
;
145DEBUG_COUNTER(PHIOfOpsCounter, "newgvn-phi",static const unsigned PHIOfOpsCounter = DebugCounter::registerCounter
("newgvn-phi", "Controls which instructions we create phi of ops for"
)
146 "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"
)
;
147// Currently store defining access refinement is too slow due to basicaa being
148// egregiously slow. This flag lets us keep it working while we work on this
149// issue.
150static cl::opt<bool> EnableStoreRefinement("enable-store-refinement",
151 cl::init(false), cl::Hidden);
152
153/// Currently, the generation "phi of ops" can result in correctness issues.
154static cl::opt<bool> EnablePhiOfOps("enable-phi-of-ops", cl::init(true),
155 cl::Hidden);
156
157//===----------------------------------------------------------------------===//
158// GVN Pass
159//===----------------------------------------------------------------------===//
160
161// Anchor methods.
162namespace llvm {
163namespace GVNExpression {
164
165Expression::~Expression() = default;
166BasicExpression::~BasicExpression() = default;
167CallExpression::~CallExpression() = default;
168LoadExpression::~LoadExpression() = default;
169StoreExpression::~StoreExpression() = default;
170AggregateValueExpression::~AggregateValueExpression() = default;
171PHIExpression::~PHIExpression() = default;
172
173} // end namespace GVNExpression
174} // end namespace llvm
175
176namespace {
177
178// Tarjan's SCC finding algorithm with Nuutila's improvements
179// SCCIterator is actually fairly complex for the simple thing we want.
180// It also wants to hand us SCC's that are unrelated to the phi node we ask
181// about, and have us process them there or risk redoing work.
182// Graph traits over a filter iterator also doesn't work that well here.
183// This SCC finder is specialized to walk use-def chains, and only follows
184// instructions,
185// not generic values (arguments, etc).
186struct TarjanSCC {
187 TarjanSCC() : Components(1) {}
188
189 void Start(const Instruction *Start) {
190 if (Root.lookup(Start) == 0)
191 FindSCC(Start);
192 }
193
194 const SmallPtrSetImpl<const Value *> &getComponentFor(const Value *V) const {
195 unsigned ComponentID = ValueToComponent.lookup(V);
196
197 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 198, __PRETTY_FUNCTION__))
198 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 198, __PRETTY_FUNCTION__))
;
199 return Components[ComponentID];
200 }
201
202private:
203 void FindSCC(const Instruction *I) {
204 Root[I] = ++DFSNum;
205 // Store the DFS Number we had before it possibly gets incremented.
206 unsigned int OurDFS = DFSNum;
207 for (auto &Op : I->operands()) {
208 if (auto *InstOp = dyn_cast<Instruction>(Op)) {
209 if (Root.lookup(Op) == 0)
210 FindSCC(InstOp);
211 if (!InComponent.count(Op))
212 Root[I] = std::min(Root.lookup(I), Root.lookup(Op));
213 }
214 }
215 // See if we really were the root of a component, by seeing if we still have
216 // our DFSNumber. If we do, we are the root of the component, and we have
217 // completed a component. If we do not, we are not the root of a component,
218 // and belong on the component stack.
219 if (Root.lookup(I) == OurDFS) {
220 unsigned ComponentID = Components.size();
221 Components.resize(Components.size() + 1);
222 auto &Component = Components.back();
223 Component.insert(I);
224 LLVM_DEBUG(dbgs() << "Component root is " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Component root is " << *
I << "\n"; } } while (false)
;
225 InComponent.insert(I);
226 ValueToComponent[I] = ComponentID;
227 // Pop a component off the stack and label it.
228 while (!Stack.empty() && Root.lookup(Stack.back()) >= OurDFS) {
229 auto *Member = Stack.back();
230 LLVM_DEBUG(dbgs() << "Component member is " << *Member << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Component member is " <<
*Member << "\n"; } } while (false)
;
231 Component.insert(Member);
232 InComponent.insert(Member);
233 ValueToComponent[Member] = ComponentID;
234 Stack.pop_back();
235 }
236 } else {
237 // Part of a component, push to stack
238 Stack.push_back(I);
239 }
240 }
241
242 unsigned int DFSNum = 1;
243 SmallPtrSet<const Value *, 8> InComponent;
244 DenseMap<const Value *, unsigned int> Root;
245 SmallVector<const Value *, 8> Stack;
246
247 // Store the components as vector of ptr sets, because we need the topo order
248 // of SCC's, but not individual member order
249 SmallVector<SmallPtrSet<const Value *, 8>, 8> Components;
250
251 DenseMap<const Value *, unsigned> ValueToComponent;
252};
253
254// Congruence classes represent the set of expressions/instructions
255// that are all the same *during some scope in the function*.
256// That is, because of the way we perform equality propagation, and
257// because of memory value numbering, it is not correct to assume
258// you can willy-nilly replace any member with any other at any
259// point in the function.
260//
261// For any Value in the Member set, it is valid to replace any dominated member
262// with that Value.
263//
264// Every congruence class has a leader, and the leader is used to symbolize
265// instructions in a canonical way (IE every operand of an instruction that is a
266// member of the same congruence class will always be replaced with leader
267// during symbolization). To simplify symbolization, we keep the leader as a
268// constant if class can be proved to be a constant value. Otherwise, the
269// leader is the member of the value set with the smallest DFS number. Each
270// congruence class also has a defining expression, though the expression may be
271// null. If it exists, it can be used for forward propagation and reassociation
272// of values.
273
274// For memory, we also track a representative MemoryAccess, and a set of memory
275// members for MemoryPhis (which have no real instructions). Note that for
276// memory, it seems tempting to try to split the memory members into a
277// MemoryCongruenceClass or something. Unfortunately, this does not work
278// easily. The value numbering of a given memory expression depends on the
279// leader of the memory congruence class, and the leader of memory congruence
280// class depends on the value numbering of a given memory expression. This
281// leads to wasted propagation, and in some cases, missed optimization. For
282// example: If we had value numbered two stores together before, but now do not,
283// we move them to a new value congruence class. This in turn will move at one
284// of the memorydefs to a new memory congruence class. Which in turn, affects
285// the value numbering of the stores we just value numbered (because the memory
286// congruence class is part of the value number). So while theoretically
287// possible to split them up, it turns out to be *incredibly* complicated to get
288// it to work right, because of the interdependency. While structurally
289// slightly messier, it is algorithmically much simpler and faster to do what we
290// do here, and track them both at once in the same class.
291// Note: The default iterators for this class iterate over values
292class CongruenceClass {
293public:
294 using MemberType = Value;
295 using MemberSet = SmallPtrSet<MemberType *, 4>;
296 using MemoryMemberType = MemoryPhi;
297 using MemoryMemberSet = SmallPtrSet<const MemoryMemberType *, 2>;
298
299 explicit CongruenceClass(unsigned ID) : ID(ID) {}
300 CongruenceClass(unsigned ID, Value *Leader, const Expression *E)
301 : ID(ID), RepLeader(Leader), DefiningExpr(E) {}
302
303 unsigned getID() const { return ID; }
304
305 // True if this class has no members left. This is mainly used for assertion
306 // purposes, and for skipping empty classes.
307 bool isDead() const {
308 // If it's both dead from a value perspective, and dead from a memory
309 // perspective, it's really dead.
310 return empty() && memory_empty();
311 }
312
313 // Leader functions
314 Value *getLeader() const { return RepLeader; }
315 void setLeader(Value *Leader) { RepLeader = Leader; }
316 const std::pair<Value *, unsigned int> &getNextLeader() const {
317 return NextLeader;
318 }
319 void resetNextLeader() { NextLeader = {nullptr, ~0}; }
320 void addPossibleNextLeader(std::pair<Value *, unsigned int> LeaderPair) {
321 if (LeaderPair.second < NextLeader.second)
322 NextLeader = LeaderPair;
323 }
324
325 Value *getStoredValue() const { return RepStoredValue; }
326 void setStoredValue(Value *Leader) { RepStoredValue = Leader; }
327 const MemoryAccess *getMemoryLeader() const { return RepMemoryAccess; }
328 void setMemoryLeader(const MemoryAccess *Leader) { RepMemoryAccess = Leader; }
329
330 // Forward propagation info
331 const Expression *getDefiningExpr() const { return DefiningExpr; }
332
333 // Value member set
334 bool empty() const { return Members.empty(); }
335 unsigned size() const { return Members.size(); }
336 MemberSet::const_iterator begin() const { return Members.begin(); }
337 MemberSet::const_iterator end() const { return Members.end(); }
338 void insert(MemberType *M) { Members.insert(M); }
339 void erase(MemberType *M) { Members.erase(M); }
340 void swap(MemberSet &Other) { Members.swap(Other); }
341
342 // Memory member set
343 bool memory_empty() const { return MemoryMembers.empty(); }
344 unsigned memory_size() const { return MemoryMembers.size(); }
345 MemoryMemberSet::const_iterator memory_begin() const {
346 return MemoryMembers.begin();
347 }
348 MemoryMemberSet::const_iterator memory_end() const {
349 return MemoryMembers.end();
350 }
351 iterator_range<MemoryMemberSet::const_iterator> memory() const {
352 return make_range(memory_begin(), memory_end());
353 }
354
355 void memory_insert(const MemoryMemberType *M) { MemoryMembers.insert(M); }
356 void memory_erase(const MemoryMemberType *M) { MemoryMembers.erase(M); }
357
358 // Store count
359 unsigned getStoreCount() const { return StoreCount; }
360 void incStoreCount() { ++StoreCount; }
361 void decStoreCount() {
362 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 362, __PRETTY_FUNCTION__))
;
363 --StoreCount;
364 }
365
366 // True if this class has no memory members.
367 bool definesNoMemory() const { return StoreCount == 0 && memory_empty(); }
368
369 // Return true if two congruence classes are equivalent to each other. This
370 // means that every field but the ID number and the dead field are equivalent.
371 bool isEquivalentTo(const CongruenceClass *Other) const {
372 if (!Other)
373 return false;
374 if (this == Other)
375 return true;
376
377 if (std::tie(StoreCount, RepLeader, RepStoredValue, RepMemoryAccess) !=
378 std::tie(Other->StoreCount, Other->RepLeader, Other->RepStoredValue,
379 Other->RepMemoryAccess))
380 return false;
381 if (DefiningExpr != Other->DefiningExpr)
382 if (!DefiningExpr || !Other->DefiningExpr ||
383 *DefiningExpr != *Other->DefiningExpr)
384 return false;
385
386 if (Members.size() != Other->Members.size())
387 return false;
388
389 return all_of(Members,
390 [&](const Value *V) { return Other->Members.count(V); });
391 }
392
393private:
394 unsigned ID;
395
396 // Representative leader.
397 Value *RepLeader = nullptr;
398
399 // The most dominating leader after our current leader, because the member set
400 // is not sorted and is expensive to keep sorted all the time.
401 std::pair<Value *, unsigned int> NextLeader = {nullptr, ~0U};
402
403 // If this is represented by a store, the value of the store.
404 Value *RepStoredValue = nullptr;
405
406 // If this class contains MemoryDefs or MemoryPhis, this is the leading memory
407 // access.
408 const MemoryAccess *RepMemoryAccess = nullptr;
409
410 // Defining Expression.
411 const Expression *DefiningExpr = nullptr;
412
413 // Actual members of this class.
414 MemberSet Members;
415
416 // This is the set of MemoryPhis that exist in the class. MemoryDefs and
417 // MemoryUses have real instructions representing them, so we only need to
418 // track MemoryPhis here.
419 MemoryMemberSet MemoryMembers;
420
421 // Number of stores in this congruence class.
422 // This is used so we can detect store equivalence changes properly.
423 int StoreCount = 0;
424};
425
426} // end anonymous namespace
427
428namespace llvm {
429
430struct ExactEqualsExpression {
431 const Expression &E;
432
433 explicit ExactEqualsExpression(const Expression &E) : E(E) {}
434
435 hash_code getComputedHash() const { return E.getComputedHash(); }
436
437 bool operator==(const Expression &Other) const {
438 return E.exactlyEquals(Other);
439 }
440};
441
442template <> struct DenseMapInfo<const Expression *> {
443 static const Expression *getEmptyKey() {
444 auto Val = static_cast<uintptr_t>(-1);
445 Val <<= PointerLikeTypeTraits<const Expression *>::NumLowBitsAvailable;
446 return reinterpret_cast<const Expression *>(Val);
447 }
448
449 static const Expression *getTombstoneKey() {
450 auto Val = static_cast<uintptr_t>(~1U);
451 Val <<= PointerLikeTypeTraits<const Expression *>::NumLowBitsAvailable;
452 return reinterpret_cast<const Expression *>(Val);
453 }
454
455 static unsigned getHashValue(const Expression *E) {
456 return E->getComputedHash();
457 }
458
459 static unsigned getHashValue(const ExactEqualsExpression &E) {
460 return E.getComputedHash();
461 }
462
463 static bool isEqual(const ExactEqualsExpression &LHS, const Expression *RHS) {
464 if (RHS == getTombstoneKey() || RHS == getEmptyKey())
465 return false;
466 return LHS == *RHS;
467 }
468
469 static bool isEqual(const Expression *LHS, const Expression *RHS) {
470 if (LHS == RHS)
471 return true;
472 if (LHS == getTombstoneKey() || RHS == getTombstoneKey() ||
473 LHS == getEmptyKey() || RHS == getEmptyKey())
474 return false;
475 // Compare hashes before equality. This is *not* what the hashtable does,
476 // since it is computing it modulo the number of buckets, whereas we are
477 // using the full hash keyspace. Since the hashes are precomputed, this
478 // check is *much* faster than equality.
479 if (LHS->getComputedHash() != RHS->getComputedHash())
480 return false;
481 return *LHS == *RHS;
482 }
483};
484
485} // end namespace llvm
486
487namespace {
488
489class NewGVN {
490 Function &F;
491 DominatorTree *DT;
492 const TargetLibraryInfo *TLI;
493 AliasAnalysis *AA;
494 MemorySSA *MSSA;
495 MemorySSAWalker *MSSAWalker;
496 const DataLayout &DL;
497 std::unique_ptr<PredicateInfo> PredInfo;
498
499 // These are the only two things the create* functions should have
500 // side-effects on due to allocating memory.
501 mutable BumpPtrAllocator ExpressionAllocator;
502 mutable ArrayRecycler<Value *> ArgRecycler;
503 mutable TarjanSCC SCCFinder;
504 const SimplifyQuery SQ;
505
506 // Number of function arguments, used by ranking
507 unsigned int NumFuncArgs;
508
509 // RPOOrdering of basic blocks
510 DenseMap<const DomTreeNode *, unsigned> RPOOrdering;
511
512 // Congruence class info.
513
514 // This class is called INITIAL in the paper. It is the class everything
515 // startsout in, and represents any value. Being an optimistic analysis,
516 // anything in the TOP class has the value TOP, which is indeterminate and
517 // equivalent to everything.
518 CongruenceClass *TOPClass;
519 std::vector<CongruenceClass *> CongruenceClasses;
520 unsigned NextCongruenceNum;
521
522 // Value Mappings.
523 DenseMap<Value *, CongruenceClass *> ValueToClass;
524 DenseMap<Value *, const Expression *> ValueToExpression;
525
526 // Value PHI handling, used to make equivalence between phi(op, op) and
527 // op(phi, phi).
528 // These mappings just store various data that would normally be part of the
529 // IR.
530 SmallPtrSet<const Instruction *, 8> PHINodeUses;
531
532 DenseMap<const Value *, bool> OpSafeForPHIOfOps;
533
534 // Map a temporary instruction we created to a parent block.
535 DenseMap<const Value *, BasicBlock *> TempToBlock;
536
537 // Map between the already in-program instructions and the temporary phis we
538 // created that they are known equivalent to.
539 DenseMap<const Value *, PHINode *> RealToTemp;
540
541 // In order to know when we should re-process instructions that have
542 // phi-of-ops, we track the set of expressions that they needed as
543 // leaders. When we discover new leaders for those expressions, we process the
544 // associated phi-of-op instructions again in case they have changed. The
545 // other way they may change is if they had leaders, and those leaders
546 // disappear. However, at the point they have leaders, there are uses of the
547 // relevant operands in the created phi node, and so they will get reprocessed
548 // through the normal user marking we perform.
549 mutable DenseMap<const Value *, SmallPtrSet<Value *, 2>> AdditionalUsers;
550 DenseMap<const Expression *, SmallPtrSet<Instruction *, 2>>
551 ExpressionToPhiOfOps;
552
553 // Map from temporary operation to MemoryAccess.
554 DenseMap<const Instruction *, MemoryUseOrDef *> TempToMemory;
555
556 // Set of all temporary instructions we created.
557 // Note: This will include instructions that were just created during value
558 // numbering. The way to test if something is using them is to check
559 // RealToTemp.
560 DenseSet<Instruction *> AllTempInstructions;
561
562 // This is the set of instructions to revisit on a reachability change. At
563 // the end of the main iteration loop it will contain at least all the phi of
564 // ops instructions that will be changed to phis, as well as regular phis.
565 // During the iteration loop, it may contain other things, such as phi of ops
566 // instructions that used edge reachability to reach a result, and so need to
567 // be revisited when the edge changes, independent of whether the phi they
568 // depended on changes.
569 DenseMap<BasicBlock *, SparseBitVector<>> RevisitOnReachabilityChange;
570
571 // Mapping from predicate info we used to the instructions we used it with.
572 // In order to correctly ensure propagation, we must keep track of what
573 // comparisons we used, so that when the values of the comparisons change, we
574 // propagate the information to the places we used the comparison.
575 mutable DenseMap<const Value *, SmallPtrSet<Instruction *, 2>>
576 PredicateToUsers;
577
578 // the same reasoning as PredicateToUsers. When we skip MemoryAccesses for
579 // stores, we no longer can rely solely on the def-use chains of MemorySSA.
580 mutable DenseMap<const MemoryAccess *, SmallPtrSet<MemoryAccess *, 2>>
581 MemoryToUsers;
582
583 // A table storing which memorydefs/phis represent a memory state provably
584 // equivalent to another memory state.
585 // We could use the congruence class machinery, but the MemoryAccess's are
586 // abstract memory states, so they can only ever be equivalent to each other,
587 // and not to constants, etc.
588 DenseMap<const MemoryAccess *, CongruenceClass *> MemoryAccessToClass;
589
590 // We could, if we wanted, build MemoryPhiExpressions and
591 // MemoryVariableExpressions, etc, and value number them the same way we value
592 // number phi expressions. For the moment, this seems like overkill. They
593 // can only exist in one of three states: they can be TOP (equal to
594 // everything), Equivalent to something else, or unique. Because we do not
595 // create expressions for them, we need to simulate leader change not just
596 // when they change class, but when they change state. Note: We can do the
597 // same thing for phis, and avoid having phi expressions if we wanted, We
598 // should eventually unify in one direction or the other, so this is a little
599 // bit of an experiment in which turns out easier to maintain.
600 enum MemoryPhiState { MPS_Invalid, MPS_TOP, MPS_Equivalent, MPS_Unique };
601 DenseMap<const MemoryPhi *, MemoryPhiState> MemoryPhiState;
602
603 enum InstCycleState { ICS_Unknown, ICS_CycleFree, ICS_Cycle };
604 mutable DenseMap<const Instruction *, InstCycleState> InstCycleState;
605
606 // Expression to class mapping.
607 using ExpressionClassMap = DenseMap<const Expression *, CongruenceClass *>;
608 ExpressionClassMap ExpressionToClass;
609
610 // We have a single expression that represents currently DeadExpressions.
611 // For dead expressions we can prove will stay dead, we mark them with
612 // DFS number zero. However, it's possible in the case of phi nodes
613 // for us to assume/prove all arguments are dead during fixpointing.
614 // We use DeadExpression for that case.
615 DeadExpression *SingletonDeadExpression = nullptr;
616
617 // Which values have changed as a result of leader changes.
618 SmallPtrSet<Value *, 8> LeaderChanges;
619
620 // Reachability info.
621 using BlockEdge = BasicBlockEdge;
622 DenseSet<BlockEdge> ReachableEdges;
623 SmallPtrSet<const BasicBlock *, 8> ReachableBlocks;
624
625 // This is a bitvector because, on larger functions, we may have
626 // thousands of touched instructions at once (entire blocks,
627 // instructions with hundreds of uses, etc). Even with optimization
628 // for when we mark whole blocks as touched, when this was a
629 // SmallPtrSet or DenseSet, for some functions, we spent >20% of all
630 // the time in GVN just managing this list. The bitvector, on the
631 // other hand, efficiently supports test/set/clear of both
632 // individual and ranges, as well as "find next element" This
633 // enables us to use it as a worklist with essentially 0 cost.
634 BitVector TouchedInstructions;
635
636 DenseMap<const BasicBlock *, std::pair<unsigned, unsigned>> BlockInstRange;
637
638#ifndef NDEBUG
639 // Debugging for how many times each block and instruction got processed.
640 DenseMap<const Value *, unsigned> ProcessedCount;
641#endif
642
643 // DFS info.
644 // This contains a mapping from Instructions to DFS numbers.
645 // The numbering starts at 1. An instruction with DFS number zero
646 // means that the instruction is dead.
647 DenseMap<const Value *, unsigned> InstrDFS;
648
649 // This contains the mapping DFS numbers to instructions.
650 SmallVector<Value *, 32> DFSToInstr;
651
652 // Deletion info.
653 SmallPtrSet<Instruction *, 8> InstructionsToErase;
654
655public:
656 NewGVN(Function &F, DominatorTree *DT, AssumptionCache *AC,
657 TargetLibraryInfo *TLI, AliasAnalysis *AA, MemorySSA *MSSA,
658 const DataLayout &DL)
659 : F(F), DT(DT), TLI(TLI), AA(AA), MSSA(MSSA), DL(DL),
660 PredInfo(make_unique<PredicateInfo>(F, *DT, *AC)),
661 SQ(DL, TLI, DT, AC, /*CtxI=*/nullptr, /*UseInstrInfo=*/false) {}
662
663 bool runGVN();
664
665private:
666 // Expression handling.
667 const Expression *createExpression(Instruction *) const;
668 const Expression *createBinaryExpression(unsigned, Type *, Value *, Value *,
669 Instruction *) const;
670
671 // Our canonical form for phi arguments is a pair of incoming value, incoming
672 // basic block.
673 using ValPair = std::pair<Value *, BasicBlock *>;
674
675 PHIExpression *createPHIExpression(ArrayRef<ValPair>, const Instruction *,
676 BasicBlock *, bool &HasBackEdge,
677 bool &OriginalOpsConstant) const;
678 const DeadExpression *createDeadExpression() const;
679 const VariableExpression *createVariableExpression(Value *) const;
680 const ConstantExpression *createConstantExpression(Constant *) const;
681 const Expression *createVariableOrConstant(Value *V) const;
682 const UnknownExpression *createUnknownExpression(Instruction *) const;
683 const StoreExpression *createStoreExpression(StoreInst *,
684 const MemoryAccess *) const;
685 LoadExpression *createLoadExpression(Type *, Value *, LoadInst *,
686 const MemoryAccess *) const;
687 const CallExpression *createCallExpression(CallInst *,
688 const MemoryAccess *) const;
689 const AggregateValueExpression *
690 createAggregateValueExpression(Instruction *) const;
691 bool setBasicExpressionInfo(Instruction *, BasicExpression *) const;
692
693 // Congruence class handling.
694 CongruenceClass *createCongruenceClass(Value *Leader, const Expression *E) {
695 auto *result = new CongruenceClass(NextCongruenceNum++, Leader, E);
696 CongruenceClasses.emplace_back(result);
697 return result;
698 }
699
700 CongruenceClass *createMemoryClass(MemoryAccess *MA) {
701 auto *CC = createCongruenceClass(nullptr, nullptr);
702 CC->setMemoryLeader(MA);
703 return CC;
704 }
705
706 CongruenceClass *ensureLeaderOfMemoryClass(MemoryAccess *MA) {
707 auto *CC = getMemoryClass(MA);
708 if (CC->getMemoryLeader() != MA)
709 CC = createMemoryClass(MA);
710 return CC;
711 }
712
713 CongruenceClass *createSingletonCongruenceClass(Value *Member) {
714 CongruenceClass *CClass = createCongruenceClass(Member, nullptr);
715 CClass->insert(Member);
716 ValueToClass[Member] = CClass;
717 return CClass;
718 }
719
720 void initializeCongruenceClasses(Function &F);
721 const Expression *makePossiblePHIOfOps(Instruction *,
722 SmallPtrSetImpl<Value *> &);
723 Value *findLeaderForInst(Instruction *ValueOp,
724 SmallPtrSetImpl<Value *> &Visited,
725 MemoryAccess *MemAccess, Instruction *OrigInst,
726 BasicBlock *PredBB);
727 bool OpIsSafeForPHIOfOpsHelper(Value *V, const BasicBlock *PHIBlock,
728 SmallPtrSetImpl<const Value *> &Visited,
729 SmallVectorImpl<Instruction *> &Worklist);
730 bool OpIsSafeForPHIOfOps(Value *Op, const BasicBlock *PHIBlock,
731 SmallPtrSetImpl<const Value *> &);
732 void addPhiOfOps(PHINode *Op, BasicBlock *BB, Instruction *ExistingValue);
733 void removePhiOfOps(Instruction *I, PHINode *PHITemp);
734
735 // Value number an Instruction or MemoryPhi.
736 void valueNumberMemoryPhi(MemoryPhi *);
737 void valueNumberInstruction(Instruction *);
738
739 // Symbolic evaluation.
740 const Expression *checkSimplificationResults(Expression *, Instruction *,
741 Value *) const;
742 const Expression *performSymbolicEvaluation(Value *,
743 SmallPtrSetImpl<Value *> &) const;
744 const Expression *performSymbolicLoadCoercion(Type *, Value *, LoadInst *,
745 Instruction *,
746 MemoryAccess *) const;
747 const Expression *performSymbolicLoadEvaluation(Instruction *) const;
748 const Expression *performSymbolicStoreEvaluation(Instruction *) const;
749 const Expression *performSymbolicCallEvaluation(Instruction *) const;
750 void sortPHIOps(MutableArrayRef<ValPair> Ops) const;
751 const Expression *performSymbolicPHIEvaluation(ArrayRef<ValPair>,
752 Instruction *I,
753 BasicBlock *PHIBlock) const;
754 const Expression *performSymbolicAggrValueEvaluation(Instruction *) const;
755 const Expression *performSymbolicCmpEvaluation(Instruction *) const;
756 const Expression *performSymbolicPredicateInfoEvaluation(Instruction *) const;
757
758 // Congruence finding.
759 bool someEquivalentDominates(const Instruction *, const Instruction *) const;
760 Value *lookupOperandLeader(Value *) const;
761 CongruenceClass *getClassForExpression(const Expression *E) const;
762 void performCongruenceFinding(Instruction *, const Expression *);
763 void moveValueToNewCongruenceClass(Instruction *, const Expression *,
764 CongruenceClass *, CongruenceClass *);
765 void moveMemoryToNewCongruenceClass(Instruction *, MemoryAccess *,
766 CongruenceClass *, CongruenceClass *);
767 Value *getNextValueLeader(CongruenceClass *) const;
768 const MemoryAccess *getNextMemoryLeader(CongruenceClass *) const;
769 bool setMemoryClass(const MemoryAccess *From, CongruenceClass *To);
770 CongruenceClass *getMemoryClass(const MemoryAccess *MA) const;
771 const MemoryAccess *lookupMemoryLeader(const MemoryAccess *) const;
772 bool isMemoryAccessTOP(const MemoryAccess *) const;
773
774 // Ranking
775 unsigned int getRank(const Value *) const;
776 bool shouldSwapOperands(const Value *, const Value *) const;
777
778 // Reachability handling.
779 void updateReachableEdge(BasicBlock *, BasicBlock *);
780 void processOutgoingEdges(Instruction *, BasicBlock *);
781 Value *findConditionEquivalence(Value *) const;
782
783 // Elimination.
784 struct ValueDFS;
785 void convertClassToDFSOrdered(const CongruenceClass &,
786 SmallVectorImpl<ValueDFS> &,
787 DenseMap<const Value *, unsigned int> &,
788 SmallPtrSetImpl<Instruction *> &) const;
789 void convertClassToLoadsAndStores(const CongruenceClass &,
790 SmallVectorImpl<ValueDFS> &) const;
791
792 bool eliminateInstructions(Function &);
793 void replaceInstruction(Instruction *, Value *);
794 void markInstructionForDeletion(Instruction *);
795 void deleteInstructionsInBlock(BasicBlock *);
796 Value *findPHIOfOpsLeader(const Expression *, const Instruction *,
797 const BasicBlock *) const;
798
799 // New instruction creation.
800 void handleNewInstruction(Instruction *) {}
801
802 // Various instruction touch utilities
803 template <typename Map, typename KeyType, typename Func>
804 void for_each_found(Map &, const KeyType &, Func);
805 template <typename Map, typename KeyType>
806 void touchAndErase(Map &, const KeyType &);
807 void markUsersTouched(Value *);
808 void markMemoryUsersTouched(const MemoryAccess *);
809 void markMemoryDefTouched(const MemoryAccess *);
810 void markPredicateUsersTouched(Instruction *);
811 void markValueLeaderChangeTouched(CongruenceClass *CC);
812 void markMemoryLeaderChangeTouched(CongruenceClass *CC);
813 void markPhiOfOpsChanged(const Expression *E);
814 void addPredicateUsers(const PredicateBase *, Instruction *) const;
815 void addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) const;
816 void addAdditionalUsers(Value *To, Value *User) const;
817
818 // Main loop of value numbering
819 void iterateTouchedInstructions();
820
821 // Utilities.
822 void cleanupTables();
823 std::pair<unsigned, unsigned> assignDFSNumbers(BasicBlock *, unsigned);
824 void updateProcessedCount(const Value *V);
825 void verifyMemoryCongruency() const;
826 void verifyIterationSettled(Function &F);
827 void verifyStoreExpressions() const;
828 bool singleReachablePHIPath(SmallPtrSet<const MemoryAccess *, 8> &,
829 const MemoryAccess *, const MemoryAccess *) const;
830 BasicBlock *getBlockForValue(Value *V) const;
831 void deleteExpression(const Expression *E) const;
832 MemoryUseOrDef *getMemoryAccess(const Instruction *) const;
833 MemoryAccess *getDefiningAccess(const MemoryAccess *) const;
834 MemoryPhi *getMemoryAccess(const BasicBlock *) const;
835 template <class T, class Range> T *getMinDFSOfRange(const Range &) const;
836
837 unsigned InstrToDFSNum(const Value *V) const {
838 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 838, __PRETTY_FUNCTION__))
;
839 return InstrDFS.lookup(V);
840 }
841
842 unsigned InstrToDFSNum(const MemoryAccess *MA) const {
843 return MemoryToDFSNum(MA);
844 }
845
846 Value *InstrFromDFSNum(unsigned DFSNum) { return DFSToInstr[DFSNum]; }
847
848 // Given a MemoryAccess, return the relevant instruction DFS number. Note:
849 // This deliberately takes a value so it can be used with Use's, which will
850 // auto-convert to Value's but not to MemoryAccess's.
851 unsigned MemoryToDFSNum(const Value *MA) const {
852 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 853, __PRETTY_FUNCTION__))
853 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 853, __PRETTY_FUNCTION__))
;
854 return isa<MemoryUseOrDef>(MA)
855 ? InstrToDFSNum(cast<MemoryUseOrDef>(MA)->getMemoryInst())
856 : InstrDFS.lookup(MA);
857 }
858
859 bool isCycleFree(const Instruction *) const;
860 bool isBackedge(BasicBlock *From, BasicBlock *To) const;
861
862 // Debug counter info. When verifying, we have to reset the value numbering
863 // debug counter to the same state it started in to get the same results.
864 int64_t StartingVNCounter;
865};
866
867} // end anonymous namespace
868
869template <typename T>
870static bool equalsLoadStoreHelper(const T &LHS, const Expression &RHS) {
871 if (!isa<LoadExpression>(RHS) && !isa<StoreExpression>(RHS))
872 return false;
873 return LHS.MemoryExpression::equals(RHS);
874}
875
876bool LoadExpression::equals(const Expression &Other) const {
877 return equalsLoadStoreHelper(*this, Other);
878}
879
880bool StoreExpression::equals(const Expression &Other) const {
881 if (!equalsLoadStoreHelper(*this, Other))
882 return false;
883 // Make sure that store vs store includes the value operand.
884 if (const auto *S = dyn_cast<StoreExpression>(&Other))
885 if (getStoredValue() != S->getStoredValue())
886 return false;
887 return true;
888}
889
890// Determine if the edge From->To is a backedge
891bool NewGVN::isBackedge(BasicBlock *From, BasicBlock *To) const {
892 return From == To ||
893 RPOOrdering.lookup(DT->getNode(From)) >=
894 RPOOrdering.lookup(DT->getNode(To));
895}
896
897#ifndef NDEBUG
898static std::string getBlockName(const BasicBlock *B) {
899 return DOTGraphTraits<const Function *>::getSimpleNodeLabel(B, nullptr);
900}
901#endif
902
903// Get a MemoryAccess for an instruction, fake or real.
904MemoryUseOrDef *NewGVN::getMemoryAccess(const Instruction *I) const {
905 auto *Result = MSSA->getMemoryAccess(I);
906 return Result ? Result : TempToMemory.lookup(I);
907}
908
909// Get a MemoryPhi for a basic block. These are all real.
910MemoryPhi *NewGVN::getMemoryAccess(const BasicBlock *BB) const {
911 return MSSA->getMemoryAccess(BB);
912}
913
914// Get the basic block from an instruction/memory value.
915BasicBlock *NewGVN::getBlockForValue(Value *V) const {
916 if (auto *I = dyn_cast<Instruction>(V)) {
917 auto *Parent = I->getParent();
918 if (Parent)
919 return Parent;
920 Parent = TempToBlock.lookup(V);
921 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 921, __PRETTY_FUNCTION__))
;
922 return Parent;
923 }
924
925 auto *MP = dyn_cast<MemoryPhi>(V);
926 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 926, __PRETTY_FUNCTION__))
;
927 return MP->getBlock();
928}
929
930// Delete a definitely dead expression, so it can be reused by the expression
931// allocator. Some of these are not in creation functions, so we have to accept
932// const versions.
933void NewGVN::deleteExpression(const Expression *E) const {
934 assert(isa<BasicExpression>(E))((isa<BasicExpression>(E)) ? static_cast<void> (0
) : __assert_fail ("isa<BasicExpression>(E)", "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 934, __PRETTY_FUNCTION__))
;
935 auto *BE = cast<BasicExpression>(E);
936 const_cast<BasicExpression *>(BE)->deallocateOperands(ArgRecycler);
937 ExpressionAllocator.Deallocate(E);
938}
939
940// If V is a predicateinfo copy, get the thing it is a copy of.
941static Value *getCopyOf(const Value *V) {
942 if (auto *II = dyn_cast<IntrinsicInst>(V))
943 if (II->getIntrinsicID() == Intrinsic::ssa_copy)
944 return II->getOperand(0);
945 return nullptr;
946}
947
948// Return true if V is really PN, even accounting for predicateinfo copies.
949static bool isCopyOfPHI(const Value *V, const PHINode *PN) {
950 return V == PN || getCopyOf(V) == PN;
951}
952
953static bool isCopyOfAPHI(const Value *V) {
954 auto *CO = getCopyOf(V);
955 return CO && isa<PHINode>(CO);
956}
957
958// Sort PHI Operands into a canonical order. What we use here is an RPO
959// order. The BlockInstRange numbers are generated in an RPO walk of the basic
960// blocks.
961void NewGVN::sortPHIOps(MutableArrayRef<ValPair> Ops) const {
962 llvm::sort(Ops, [&](const ValPair &P1, const ValPair &P2) {
963 return BlockInstRange.lookup(P1.second).first <
964 BlockInstRange.lookup(P2.second).first;
965 });
966}
967
968// Return true if V is a value that will always be available (IE can
969// be placed anywhere) in the function. We don't do globals here
970// because they are often worse to put in place.
971static bool alwaysAvailable(Value *V) {
972 return isa<Constant>(V) || isa<Argument>(V);
973}
974
975// Create a PHIExpression from an array of {incoming edge, value} pairs. I is
976// the original instruction we are creating a PHIExpression for (but may not be
977// a phi node). We require, as an invariant, that all the PHIOperands in the
978// same block are sorted the same way. sortPHIOps will sort them into a
979// canonical order.
980PHIExpression *NewGVN::createPHIExpression(ArrayRef<ValPair> PHIOperands,
981 const Instruction *I,
982 BasicBlock *PHIBlock,
983 bool &HasBackedge,
984 bool &OriginalOpsConstant) const {
985 unsigned NumOps = PHIOperands.size();
986 auto *E = new (ExpressionAllocator) PHIExpression(NumOps, PHIBlock);
21
'E' initialized to a null pointer value
987
988 E->allocateOperands(ArgRecycler, ExpressionAllocator);
22
Called C++ object pointer is null
989 E->setType(PHIOperands.begin()->first->getType());
990 E->setOpcode(Instruction::PHI);
991
992 // Filter out unreachable phi operands.
993 auto Filtered = make_filter_range(PHIOperands, [&](const ValPair &P) {
994 auto *BB = P.second;
995 if (auto *PHIOp = dyn_cast<PHINode>(I))
996 if (isCopyOfPHI(P.first, PHIOp))
997 return false;
998 if (!ReachableEdges.count({BB, PHIBlock}))
999 return false;
1000 // Things in TOPClass are equivalent to everything.
1001 if (ValueToClass.lookup(P.first) == TOPClass)
1002 return false;
1003 OriginalOpsConstant = OriginalOpsConstant && isa<Constant>(P.first);
1004 HasBackedge = HasBackedge || isBackedge(BB, PHIBlock);
1005 return lookupOperandLeader(P.first) != I;
1006 });
1007 std::transform(Filtered.begin(), Filtered.end(), op_inserter(E),
1008 [&](const ValPair &P) -> Value * {
1009 return lookupOperandLeader(P.first);
1010 });
1011 return E;
1012}
1013
1014// Set basic expression info (Arguments, type, opcode) for Expression
1015// E from Instruction I in block B.
1016bool NewGVN::setBasicExpressionInfo(Instruction *I, BasicExpression *E) const {
1017 bool AllConstant = true;
1018 if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
1019 E->setType(GEP->getSourceElementType());
1020 else
1021 E->setType(I->getType());
1022 E->setOpcode(I->getOpcode());
1023 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1024
1025 // Transform the operand array into an operand leader array, and keep track of
1026 // whether all members are constant.
1027 std::transform(I->op_begin(), I->op_end(), op_inserter(E), [&](Value *O) {
1028 auto Operand = lookupOperandLeader(O);
1029 AllConstant = AllConstant && isa<Constant>(Operand);
1030 return Operand;
1031 });
1032
1033 return AllConstant;
1034}
1035
1036const Expression *NewGVN::createBinaryExpression(unsigned Opcode, Type *T,
1037 Value *Arg1, Value *Arg2,
1038 Instruction *I) const {
1039 auto *E = new (ExpressionAllocator) BasicExpression(2);
1040
1041 E->setType(T);
1042 E->setOpcode(Opcode);
1043 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1044 if (Instruction::isCommutative(Opcode)) {
1045 // Ensure that commutative instructions that only differ by a permutation
1046 // of their operands get the same value number by sorting the operand value
1047 // numbers. Since all commutative instructions have two operands it is more
1048 // efficient to sort by hand rather than using, say, std::sort.
1049 if (shouldSwapOperands(Arg1, Arg2))
1050 std::swap(Arg1, Arg2);
1051 }
1052 E->op_push_back(lookupOperandLeader(Arg1));
1053 E->op_push_back(lookupOperandLeader(Arg2));
1054
1055 Value *V = SimplifyBinOp(Opcode, E->getOperand(0), E->getOperand(1), SQ);
1056 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1057 return SimplifiedE;
1058 return E;
1059}
1060
1061// Take a Value returned by simplification of Expression E/Instruction
1062// I, and see if it resulted in a simpler expression. If so, return
1063// that expression.
1064const Expression *NewGVN::checkSimplificationResults(Expression *E,
1065 Instruction *I,
1066 Value *V) const {
1067 if (!V)
1068 return nullptr;
1069 if (auto *C = dyn_cast<Constant>(V)) {
1070 if (I)
1071 LLVM_DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " constant " << *C << "\n"; } } while
(false)
1072 << " constant " << *C << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " constant " << *C << "\n"; } } while
(false)
;
1073 NumGVNOpsSimplified++;
1074 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1075, __PRETTY_FUNCTION__))
1075 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1075, __PRETTY_FUNCTION__))
;
1076 deleteExpression(E);
1077 return createConstantExpression(C);
1078 } else if (isa<Argument>(V) || isa<GlobalVariable>(V)) {
1079 if (I)
1080 LLVM_DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " variable " << *V << "\n"; } } while
(false)
1081 << " variable " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " variable " << *V << "\n"; } } while
(false)
;
1082 deleteExpression(E);
1083 return createVariableExpression(V);
1084 }
1085
1086 CongruenceClass *CC = ValueToClass.lookup(V);
1087 if (CC) {
1088 if (CC->getLeader() && CC->getLeader() != I) {
1089 // Don't add temporary instructions to the user lists.
1090 if (!AllTempInstructions.count(I))
1091 addAdditionalUsers(V, I);
1092 return createVariableOrConstant(CC->getLeader());
1093 }
1094 if (CC->getDefiningExpr()) {
1095 // If we simplified to something else, we need to communicate
1096 // that we're users of the value we simplified to.
1097 if (I != V) {
1098 // Don't add temporary instructions to the user lists.
1099 if (!AllTempInstructions.count(I))
1100 addAdditionalUsers(V, I);
1101 }
1102
1103 if (I)
1104 LLVM_DEBUG(dbgs() << "Simplified " << *I << " to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " expression " << *CC->getDefiningExpr
() << "\n"; } } while (false)
1105 << " expression " << *CC->getDefiningExpr() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified " << *I <<
" to " << " expression " << *CC->getDefiningExpr
() << "\n"; } } while (false)
;
1106 NumGVNOpsSimplified++;
1107 deleteExpression(E);
1108 return CC->getDefiningExpr();
1109 }
1110 }
1111
1112 return nullptr;
1113}
1114
1115// Create a value expression from the instruction I, replacing operands with
1116// their leaders.
1117
1118const Expression *NewGVN::createExpression(Instruction *I) const {
1119 auto *E = new (ExpressionAllocator) BasicExpression(I->getNumOperands());
1120
1121 bool AllConstant = setBasicExpressionInfo(I, E);
1122
1123 if (I->isCommutative()) {
1124 // Ensure that commutative instructions that only differ by a permutation
1125 // of their operands get the same value number by sorting the operand value
1126 // numbers. Since all commutative instructions have two operands it is more
1127 // efficient to sort by hand rather than using, say, std::sort.
1128 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1128, __PRETTY_FUNCTION__))
;
1129 if (shouldSwapOperands(E->getOperand(0), E->getOperand(1)))
1130 E->swapOperands(0, 1);
1131 }
1132 // Perform simplification.
1133 if (auto *CI = dyn_cast<CmpInst>(I)) {
1134 // Sort the operand value numbers so x<y and y>x get the same value
1135 // number.
1136 CmpInst::Predicate Predicate = CI->getPredicate();
1137 if (shouldSwapOperands(E->getOperand(0), E->getOperand(1))) {
1138 E->swapOperands(0, 1);
1139 Predicate = CmpInst::getSwappedPredicate(Predicate);
1140 }
1141 E->setOpcode((CI->getOpcode() << 8) | Predicate);
1142 // TODO: 25% of our time is spent in SimplifyCmpInst with pointer operands
1143 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1144, __PRETTY_FUNCTION__))
1144 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1144, __PRETTY_FUNCTION__))
;
1145 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1146, __PRETTY_FUNCTION__))
1146 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1146, __PRETTY_FUNCTION__))
;
1147 Value *V =
1148 SimplifyCmpInst(Predicate, E->getOperand(0), E->getOperand(1), SQ);
1149 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1150 return SimplifiedE;
1151 } else if (isa<SelectInst>(I)) {
1152 if (isa<Constant>(E->getOperand(0)) ||
1153 E->getOperand(1) == E->getOperand(2)) {
1154 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1155, __PRETTY_FUNCTION__))
1155 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1155, __PRETTY_FUNCTION__))
;
1156 Value *V = SimplifySelectInst(E->getOperand(0), E->getOperand(1),
1157 E->getOperand(2), SQ);
1158 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1159 return SimplifiedE;
1160 }
1161 } else if (I->isBinaryOp()) {
1162 Value *V =
1163 SimplifyBinOp(E->getOpcode(), E->getOperand(0), E->getOperand(1), SQ);
1164 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1165 return SimplifiedE;
1166 } else if (auto *BI = dyn_cast<BitCastInst>(I)) {
1167 Value *V =
1168 SimplifyCastInst(BI->getOpcode(), BI->getOperand(0), BI->getType(), SQ);
1169 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1170 return SimplifiedE;
1171 } else if (isa<GetElementPtrInst>(I)) {
1172 Value *V = SimplifyGEPInst(
1173 E->getType(), ArrayRef<Value *>(E->op_begin(), E->op_end()), SQ);
1174 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1175 return SimplifiedE;
1176 } else if (AllConstant) {
1177 // We don't bother trying to simplify unless all of the operands
1178 // were constant.
1179 // TODO: There are a lot of Simplify*'s we could call here, if we
1180 // wanted to. The original motivating case for this code was a
1181 // zext i1 false to i8, which we don't have an interface to
1182 // simplify (IE there is no SimplifyZExt).
1183
1184 SmallVector<Constant *, 8> C;
1185 for (Value *Arg : E->operands())
1186 C.emplace_back(cast<Constant>(Arg));
1187
1188 if (Value *V = ConstantFoldInstOperands(I, C, DL, TLI))
1189 if (const Expression *SimplifiedE = checkSimplificationResults(E, I, V))
1190 return SimplifiedE;
1191 }
1192 return E;
1193}
1194
1195const AggregateValueExpression *
1196NewGVN::createAggregateValueExpression(Instruction *I) const {
1197 if (auto *II = dyn_cast<InsertValueInst>(I)) {
1198 auto *E = new (ExpressionAllocator)
1199 AggregateValueExpression(I->getNumOperands(), II->getNumIndices());
1200 setBasicExpressionInfo(I, E);
1201 E->allocateIntOperands(ExpressionAllocator);
1202 std::copy(II->idx_begin(), II->idx_end(), int_op_inserter(E));
1203 return E;
1204 } else if (auto *EI = dyn_cast<ExtractValueInst>(I)) {
1205 auto *E = new (ExpressionAllocator)
1206 AggregateValueExpression(I->getNumOperands(), EI->getNumIndices());
1207 setBasicExpressionInfo(EI, E);
1208 E->allocateIntOperands(ExpressionAllocator);
1209 std::copy(EI->idx_begin(), EI->idx_end(), int_op_inserter(E));
1210 return E;
1211 }
1212 llvm_unreachable("Unhandled type of aggregate value operation")::llvm::llvm_unreachable_internal("Unhandled type of aggregate value operation"
, "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1212)
;
1213}
1214
1215const DeadExpression *NewGVN::createDeadExpression() const {
1216 // DeadExpression has no arguments and all DeadExpression's are the same,
1217 // so we only need one of them.
1218 return SingletonDeadExpression;
1219}
1220
1221const VariableExpression *NewGVN::createVariableExpression(Value *V) const {
1222 auto *E = new (ExpressionAllocator) VariableExpression(V);
1223 E->setOpcode(V->getValueID());
1224 return E;
1225}
1226
1227const Expression *NewGVN::createVariableOrConstant(Value *V) const {
1228 if (auto *C = dyn_cast<Constant>(V))
1229 return createConstantExpression(C);
1230 return createVariableExpression(V);
1231}
1232
1233const ConstantExpression *NewGVN::createConstantExpression(Constant *C) const {
1234 auto *E = new (ExpressionAllocator) ConstantExpression(C);
1235 E->setOpcode(C->getValueID());
1236 return E;
1237}
1238
1239const UnknownExpression *NewGVN::createUnknownExpression(Instruction *I) const {
1240 auto *E = new (ExpressionAllocator) UnknownExpression(I);
1241 E->setOpcode(I->getOpcode());
1242 return E;
1243}
1244
1245const CallExpression *
1246NewGVN::createCallExpression(CallInst *CI, const MemoryAccess *MA) const {
1247 // FIXME: Add operand bundles for calls.
1248 auto *E =
1249 new (ExpressionAllocator) CallExpression(CI->getNumOperands(), CI, MA);
1250 setBasicExpressionInfo(CI, E);
1251 return E;
1252}
1253
1254// Return true if some equivalent of instruction Inst dominates instruction U.
1255bool NewGVN::someEquivalentDominates(const Instruction *Inst,
1256 const Instruction *U) const {
1257 auto *CC = ValueToClass.lookup(Inst);
1258 // This must be an instruction because we are only called from phi nodes
1259 // in the case that the value it needs to check against is an instruction.
1260
1261 // The most likely candidates for dominance are the leader and the next leader.
1262 // The leader or nextleader will dominate in all cases where there is an
1263 // equivalent that is higher up in the dom tree.
1264 // We can't *only* check them, however, because the
1265 // dominator tree could have an infinite number of non-dominating siblings
1266 // with instructions that are in the right congruence class.
1267 // A
1268 // B C D E F G
1269 // |
1270 // H
1271 // Instruction U could be in H, with equivalents in every other sibling.
1272 // Depending on the rpo order picked, the leader could be the equivalent in
1273 // any of these siblings.
1274 if (!CC)
1275 return false;
1276 if (alwaysAvailable(CC->getLeader()))
1277 return true;
1278 if (DT->dominates(cast<Instruction>(CC->getLeader()), U))
1279 return true;
1280 if (CC->getNextLeader().first &&
1281 DT->dominates(cast<Instruction>(CC->getNextLeader().first), U))
1282 return true;
1283 return llvm::any_of(*CC, [&](const Value *Member) {
1284 return Member != CC->getLeader() &&
1285 DT->dominates(cast<Instruction>(Member), U);
1286 });
1287}
1288
1289// See if we have a congruence class and leader for this operand, and if so,
1290// return it. Otherwise, return the operand itself.
1291Value *NewGVN::lookupOperandLeader(Value *V) const {
1292 CongruenceClass *CC = ValueToClass.lookup(V);
1293 if (CC) {
1294 // Everything in TOP is represented by undef, as it can be any value.
1295 // We do have to make sure we get the type right though, so we can't set the
1296 // RepLeader to undef.
1297 if (CC == TOPClass)
1298 return UndefValue::get(V->getType());
1299 return CC->getStoredValue() ? CC->getStoredValue() : CC->getLeader();
1300 }
1301
1302 return V;
1303}
1304
1305const MemoryAccess *NewGVN::lookupMemoryLeader(const MemoryAccess *MA) const {
1306 auto *CC = getMemoryClass(MA);
1307 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1309, __PRETTY_FUNCTION__))
1308 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1309, __PRETTY_FUNCTION__))
1309 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1309, __PRETTY_FUNCTION__))
;
1310 return CC->getMemoryLeader();
1311}
1312
1313// Return true if the MemoryAccess is really equivalent to everything. This is
1314// equivalent to the lattice value "TOP" in most lattices. This is the initial
1315// state of all MemoryAccesses.
1316bool NewGVN::isMemoryAccessTOP(const MemoryAccess *MA) const {
1317 return getMemoryClass(MA) == TOPClass;
1318}
1319
1320LoadExpression *NewGVN::createLoadExpression(Type *LoadType, Value *PointerOp,
1321 LoadInst *LI,
1322 const MemoryAccess *MA) const {
1323 auto *E =
1324 new (ExpressionAllocator) LoadExpression(1, LI, lookupMemoryLeader(MA));
1325 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1326 E->setType(LoadType);
1327
1328 // Give store and loads same opcode so they value number together.
1329 E->setOpcode(0);
1330 E->op_push_back(PointerOp);
1331 if (LI)
1332 E->setAlignment(LI->getAlignment());
1333
1334 // TODO: Value number heap versions. We may be able to discover
1335 // things alias analysis can't on it's own (IE that a store and a
1336 // load have the same value, and thus, it isn't clobbering the load).
1337 return E;
1338}
1339
1340const StoreExpression *
1341NewGVN::createStoreExpression(StoreInst *SI, const MemoryAccess *MA) const {
1342 auto *StoredValueLeader = lookupOperandLeader(SI->getValueOperand());
1343 auto *E = new (ExpressionAllocator)
1344 StoreExpression(SI->getNumOperands(), SI, StoredValueLeader, MA);
1345 E->allocateOperands(ArgRecycler, ExpressionAllocator);
1346 E->setType(SI->getValueOperand()->getType());
1347
1348 // Give store and loads same opcode so they value number together.
1349 E->setOpcode(0);
1350 E->op_push_back(lookupOperandLeader(SI->getPointerOperand()));
1351
1352 // TODO: Value number heap versions. We may be able to discover
1353 // things alias analysis can't on it's own (IE that a store and a
1354 // load have the same value, and thus, it isn't clobbering the load).
1355 return E;
1356}
1357
1358const Expression *NewGVN::performSymbolicStoreEvaluation(Instruction *I) const {
1359 // Unlike loads, we never try to eliminate stores, so we do not check if they
1360 // are simple and avoid value numbering them.
1361 auto *SI = cast<StoreInst>(I);
1362 auto *StoreAccess = getMemoryAccess(SI);
1363 // Get the expression, if any, for the RHS of the MemoryDef.
1364 const MemoryAccess *StoreRHS = StoreAccess->getDefiningAccess();
1365 if (EnableStoreRefinement)
1366 StoreRHS = MSSAWalker->getClobberingMemoryAccess(StoreAccess);
1367 // If we bypassed the use-def chains, make sure we add a use.
1368 StoreRHS = lookupMemoryLeader(StoreRHS);
1369 if (StoreRHS != StoreAccess->getDefiningAccess())
1370 addMemoryUsers(StoreRHS, StoreAccess);
1371 // If we are defined by ourselves, use the live on entry def.
1372 if (StoreRHS == StoreAccess)
1373 StoreRHS = MSSA->getLiveOnEntryDef();
1374
1375 if (SI->isSimple()) {
1376 // See if we are defined by a previous store expression, it already has a
1377 // value, and it's the same value as our current store. FIXME: Right now, we
1378 // only do this for simple stores, we should expand to cover memcpys, etc.
1379 const auto *LastStore = createStoreExpression(SI, StoreRHS);
1380 const auto *LastCC = ExpressionToClass.lookup(LastStore);
1381 // We really want to check whether the expression we matched was a store. No
1382 // easy way to do that. However, we can check that the class we found has a
1383 // store, which, assuming the value numbering state is not corrupt, is
1384 // sufficient, because we must also be equivalent to that store's expression
1385 // for it to be in the same class as the load.
1386 if (LastCC && LastCC->getStoredValue() == LastStore->getStoredValue())
1387 return LastStore;
1388 // Also check if our value operand is defined by a load of the same memory
1389 // location, and the memory state is the same as it was then (otherwise, it
1390 // could have been overwritten later. See test32 in
1391 // transforms/DeadStoreElimination/simple.ll).
1392 if (auto *LI = dyn_cast<LoadInst>(LastStore->getStoredValue()))
1393 if ((lookupOperandLeader(LI->getPointerOperand()) ==
1394 LastStore->getOperand(0)) &&
1395 (lookupMemoryLeader(getMemoryAccess(LI)->getDefiningAccess()) ==
1396 StoreRHS))
1397 return LastStore;
1398 deleteExpression(LastStore);
1399 }
1400
1401 // If the store is not equivalent to anything, value number it as a store that
1402 // produces a unique memory state (instead of using it's MemoryUse, we use
1403 // it's MemoryDef).
1404 return createStoreExpression(SI, StoreAccess);
1405}
1406
1407// See if we can extract the value of a loaded pointer from a load, a store, or
1408// a memory instruction.
1409const Expression *
1410NewGVN::performSymbolicLoadCoercion(Type *LoadType, Value *LoadPtr,
1411 LoadInst *LI, Instruction *DepInst,
1412 MemoryAccess *DefiningAccess) const {
1413 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1413, __PRETTY_FUNCTION__))
;
1414 if (auto *DepSI = dyn_cast<StoreInst>(DepInst)) {
1415 // Can't forward from non-atomic to atomic without violating memory model.
1416 // Also don't need to coerce if they are the same type, we will just
1417 // propagate.
1418 if (LI->isAtomic() > DepSI->isAtomic() ||
1419 LoadType == DepSI->getValueOperand()->getType())
1420 return nullptr;
1421 int Offset = analyzeLoadFromClobberingStore(LoadType, LoadPtr, DepSI, DL);
1422 if (Offset >= 0) {
1423 if (auto *C = dyn_cast<Constant>(
1424 lookupOperandLeader(DepSI->getValueOperand()))) {
1425 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)
1426 << " to constant " << *C << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from store " <<
*DepSI << " to constant " << *C << "\n"; }
} while (false)
;
1427 return createConstantExpression(
1428 getConstantStoreValueForLoad(C, Offset, LoadType, DL));
1429 }
1430 }
1431 } else if (auto *DepLI = dyn_cast<LoadInst>(DepInst)) {
1432 // Can't forward from non-atomic to atomic without violating memory model.
1433 if (LI->isAtomic() > DepLI->isAtomic())
1434 return nullptr;
1435 int Offset = analyzeLoadFromClobberingLoad(LoadType, LoadPtr, DepLI, DL);
1436 if (Offset >= 0) {
1437 // We can coerce a constant load into a load.
1438 if (auto *C = dyn_cast<Constant>(lookupOperandLeader(DepLI)))
1439 if (auto *PossibleConstant =
1440 getConstantLoadValueForLoad(C, Offset, LoadType, DL)) {
1441 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)
1442 << " to constant " << *PossibleConstant << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from load " <<
*LI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
;
1443 return createConstantExpression(PossibleConstant);
1444 }
1445 }
1446 } else if (auto *DepMI = dyn_cast<MemIntrinsic>(DepInst)) {
1447 int Offset = analyzeLoadFromClobberingMemInst(LoadType, LoadPtr, DepMI, DL);
1448 if (Offset >= 0) {
1449 if (auto *PossibleConstant =
1450 getConstantMemInstValueForLoad(DepMI, Offset, LoadType, DL)) {
1451 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)
1452 << " to constant " << *PossibleConstant << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Coercing load from meminst " <<
*DepMI << " to constant " << *PossibleConstant <<
"\n"; } } while (false)
;
1453 return createConstantExpression(PossibleConstant);
1454 }
1455 }
1456 }
1457
1458 // All of the below are only true if the loaded pointer is produced
1459 // by the dependent instruction.
1460 if (LoadPtr != lookupOperandLeader(DepInst) &&
1461 !AA->isMustAlias(LoadPtr, DepInst))
1462 return nullptr;
1463 // If this load really doesn't depend on anything, then we must be loading an
1464 // undef value. This can happen when loading for a fresh allocation with no
1465 // intervening stores, for example. Note that this is only true in the case
1466 // that the result of the allocation is pointer equal to the load ptr.
1467 if (isa<AllocaInst>(DepInst) || isMallocLikeFn(DepInst, TLI)) {
1468 return createConstantExpression(UndefValue::get(LoadType));
1469 }
1470 // If this load occurs either right after a lifetime begin,
1471 // then the loaded value is undefined.
1472 else if (auto *II = dyn_cast<IntrinsicInst>(DepInst)) {
1473 if (II->getIntrinsicID() == Intrinsic::lifetime_start)
1474 return createConstantExpression(UndefValue::get(LoadType));
1475 }
1476 // If this load follows a calloc (which zero initializes memory),
1477 // then the loaded value is zero
1478 else if (isCallocLikeFn(DepInst, TLI)) {
1479 return createConstantExpression(Constant::getNullValue(LoadType));
1480 }
1481
1482 return nullptr;
1483}
1484
1485const Expression *NewGVN::performSymbolicLoadEvaluation(Instruction *I) const {
1486 auto *LI = cast<LoadInst>(I);
1487
1488 // We can eliminate in favor of non-simple loads, but we won't be able to
1489 // eliminate the loads themselves.
1490 if (!LI->isSimple())
1491 return nullptr;
1492
1493 Value *LoadAddressLeader = lookupOperandLeader(LI->getPointerOperand());
1494 // Load of undef is undef.
1495 if (isa<UndefValue>(LoadAddressLeader))
1496 return createConstantExpression(UndefValue::get(LI->getType()));
1497 MemoryAccess *OriginalAccess = getMemoryAccess(I);
1498 MemoryAccess *DefiningAccess =
1499 MSSAWalker->getClobberingMemoryAccess(OriginalAccess);
1500
1501 if (!MSSA->isLiveOnEntryDef(DefiningAccess)) {
1502 if (auto *MD = dyn_cast<MemoryDef>(DefiningAccess)) {
1503 Instruction *DefiningInst = MD->getMemoryInst();
1504 // If the defining instruction is not reachable, replace with undef.
1505 if (!ReachableBlocks.count(DefiningInst->getParent()))
1506 return createConstantExpression(UndefValue::get(LI->getType()));
1507 // This will handle stores and memory insts. We only do if it the
1508 // defining access has a different type, or it is a pointer produced by
1509 // certain memory operations that cause the memory to have a fixed value
1510 // (IE things like calloc).
1511 if (const auto *CoercionResult =
1512 performSymbolicLoadCoercion(LI->getType(), LoadAddressLeader, LI,
1513 DefiningInst, DefiningAccess))
1514 return CoercionResult;
1515 }
1516 }
1517
1518 const auto *LE = createLoadExpression(LI->getType(), LoadAddressLeader, LI,
1519 DefiningAccess);
1520 // If our MemoryLeader is not our defining access, add a use to the
1521 // MemoryLeader, so that we get reprocessed when it changes.
1522 if (LE->getMemoryLeader() != DefiningAccess)
1523 addMemoryUsers(LE->getMemoryLeader(), OriginalAccess);
1524 return LE;
1525}
1526
1527const Expression *
1528NewGVN::performSymbolicPredicateInfoEvaluation(Instruction *I) const {
1529 auto *PI = PredInfo->getPredicateInfoFor(I);
1530 if (!PI)
1531 return nullptr;
1532
1533 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)
;
1534
1535 auto *PWC = dyn_cast<PredicateWithCondition>(PI);
1536 if (!PWC)
1537 return nullptr;
1538
1539 auto *CopyOf = I->getOperand(0);
1540 auto *Cond = PWC->Condition;
1541
1542 // If this a copy of the condition, it must be either true or false depending
1543 // on the predicate info type and edge.
1544 if (CopyOf == Cond) {
1545 // We should not need to add predicate users because the predicate info is
1546 // already a use of this operand.
1547 if (isa<PredicateAssume>(PI))
1548 return createConstantExpression(ConstantInt::getTrue(Cond->getType()));
1549 if (auto *PBranch = dyn_cast<PredicateBranch>(PI)) {
1550 if (PBranch->TrueEdge)
1551 return createConstantExpression(ConstantInt::getTrue(Cond->getType()));
1552 return createConstantExpression(ConstantInt::getFalse(Cond->getType()));
1553 }
1554 if (auto *PSwitch = dyn_cast<PredicateSwitch>(PI))
1555 return createConstantExpression(cast<Constant>(PSwitch->CaseValue));
1556 }
1557
1558 // Not a copy of the condition, so see what the predicates tell us about this
1559 // value. First, though, we check to make sure the value is actually a copy
1560 // of one of the condition operands. It's possible, in certain cases, for it
1561 // to be a copy of a predicateinfo copy. In particular, if two branch
1562 // operations use the same condition, and one branch dominates the other, we
1563 // will end up with a copy of a copy. This is currently a small deficiency in
1564 // predicateinfo. What will end up happening here is that we will value
1565 // number both copies the same anyway.
1566
1567 // Everything below relies on the condition being a comparison.
1568 auto *Cmp = dyn_cast<CmpInst>(Cond);
1569 if (!Cmp)
1570 return nullptr;
1571
1572 if (CopyOf != Cmp->getOperand(0) && CopyOf != Cmp->getOperand(1)) {
1573 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)
;
1574 return nullptr;
1575 }
1576 Value *FirstOp = lookupOperandLeader(Cmp->getOperand(0));
1577 Value *SecondOp = lookupOperandLeader(Cmp->getOperand(1));
1578 bool SwappedOps = false;
1579 // Sort the ops.
1580 if (shouldSwapOperands(FirstOp, SecondOp)) {
1581 std::swap(FirstOp, SecondOp);
1582 SwappedOps = true;
1583 }
1584 CmpInst::Predicate Predicate =
1585 SwappedOps ? Cmp->getSwappedPredicate() : Cmp->getPredicate();
1586
1587 if (isa<PredicateAssume>(PI)) {
1588 // If we assume the operands are equal, then they are equal.
1589 if (Predicate == CmpInst::ICMP_EQ) {
1590 addPredicateUsers(PI, I);
1591 addAdditionalUsers(SwappedOps ? Cmp->getOperand(1) : Cmp->getOperand(0),
1592 I);
1593 return createVariableOrConstant(FirstOp);
1594 }
1595 }
1596 if (const auto *PBranch = dyn_cast<PredicateBranch>(PI)) {
1597 // If we are *not* a copy of the comparison, we may equal to the other
1598 // operand when the predicate implies something about equality of
1599 // operations. In particular, if the comparison is true/false when the
1600 // operands are equal, and we are on the right edge, we know this operation
1601 // is equal to something.
1602 if ((PBranch->TrueEdge && Predicate == CmpInst::ICMP_EQ) ||
1603 (!PBranch->TrueEdge && Predicate == CmpInst::ICMP_NE)) {
1604 addPredicateUsers(PI, I);
1605 addAdditionalUsers(SwappedOps ? Cmp->getOperand(1) : Cmp->getOperand(0),
1606 I);
1607 return createVariableOrConstant(FirstOp);
1608 }
1609 // Handle the special case of floating point.
1610 if (((PBranch->TrueEdge && Predicate == CmpInst::FCMP_OEQ) ||
1611 (!PBranch->TrueEdge && Predicate == CmpInst::FCMP_UNE)) &&
1612 isa<ConstantFP>(FirstOp) && !cast<ConstantFP>(FirstOp)->isZero()) {
1613 addPredicateUsers(PI, I);
1614 addAdditionalUsers(SwappedOps ? Cmp->getOperand(1) : Cmp->getOperand(0),
1615 I);
1616 return createConstantExpression(cast<Constant>(FirstOp));
1617 }
1618 }
1619 return nullptr;
1620}
1621
1622// Evaluate read only and pure calls, and create an expression result.
1623const Expression *NewGVN::performSymbolicCallEvaluation(Instruction *I) const {
1624 auto *CI = cast<CallInst>(I);
1625 if (auto *II = dyn_cast<IntrinsicInst>(I)) {
1626 // Intrinsics with the returned attribute are copies of arguments.
1627 if (auto *ReturnedValue = II->getReturnedArgOperand()) {
1628 if (II->getIntrinsicID() == Intrinsic::ssa_copy)
1629 if (const auto *Result = performSymbolicPredicateInfoEvaluation(I))
1630 return Result;
1631 return createVariableOrConstant(ReturnedValue);
1632 }
1633 }
1634 if (AA->doesNotAccessMemory(CI)) {
1635 return createCallExpression(CI, TOPClass->getMemoryLeader());
1636 } else if (AA->onlyReadsMemory(CI)) {
1637 MemoryAccess *DefiningAccess = MSSAWalker->getClobberingMemoryAccess(CI);
1638 return createCallExpression(CI, DefiningAccess);
1639 }
1640 return nullptr;
1641}
1642
1643// Retrieve the memory class for a given MemoryAccess.
1644CongruenceClass *NewGVN::getMemoryClass(const MemoryAccess *MA) const {
1645 auto *Result = MemoryAccessToClass.lookup(MA);
1646 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1646, __PRETTY_FUNCTION__))
;
1647 return Result;
1648}
1649
1650// Update the MemoryAccess equivalence table to say that From is equal to To,
1651// and return true if this is different from what already existed in the table.
1652bool NewGVN::setMemoryClass(const MemoryAccess *From,
1653 CongruenceClass *NewClass) {
1654 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1655, __PRETTY_FUNCTION__))
1655 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1655, __PRETTY_FUNCTION__))
;
1656 LLVM_DEBUG(dbgs() << "Setting " << *From)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Setting " << *From; } } while
(false)
;
1657 LLVM_DEBUG(dbgs() << " equivalent to congruence class ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " equivalent to congruence class "
; } } while (false)
;
1658 LLVM_DEBUG(dbgs() << NewClass->getID()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << NewClass->getID() << " with current MemoryAccess leader "
; } } while (false)
1659 << " with current MemoryAccess leader ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << NewClass->getID() << " with current MemoryAccess leader "
; } } while (false)
;
1660 LLVM_DEBUG(dbgs() << *NewClass->getMemoryLeader() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << *NewClass->getMemoryLeader()
<< "\n"; } } while (false)
;
1661
1662 auto LookupResult = MemoryAccessToClass.find(From);
1663 bool Changed = false;
1664 // If it's already in the table, see if the value changed.
1665 if (LookupResult != MemoryAccessToClass.end()) {
1666 auto *OldClass = LookupResult->second;
1667 if (OldClass != NewClass) {
1668 // If this is a phi, we have to handle memory member updates.
1669 if (auto *MP = dyn_cast<MemoryPhi>(From)) {
1670 OldClass->memory_erase(MP);
1671 NewClass->memory_insert(MP);
1672 // This may have killed the class if it had no non-memory members
1673 if (OldClass->getMemoryLeader() == From) {
1674 if (OldClass->definesNoMemory()) {
1675 OldClass->setMemoryLeader(nullptr);
1676 } else {
1677 OldClass->setMemoryLeader(getNextMemoryLeader(OldClass));
1678 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)
1679 << 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)
1680 << *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)
1681 << " 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)
1682 << "\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)
;
1683 markMemoryLeaderChangeTouched(OldClass);
1684 }
1685 }
1686 }
1687 // It wasn't equivalent before, and now it is.
1688 LookupResult->second = NewClass;
1689 Changed = true;
1690 }
1691 }
1692
1693 return Changed;
1694}
1695
1696// Determine if a instruction is cycle-free. That means the values in the
1697// instruction don't depend on any expressions that can change value as a result
1698// of the instruction. For example, a non-cycle free instruction would be v =
1699// phi(0, v+1).
1700bool NewGVN::isCycleFree(const Instruction *I) const {
1701 // In order to compute cycle-freeness, we do SCC finding on the instruction,
1702 // and see what kind of SCC it ends up in. If it is a singleton, it is
1703 // cycle-free. If it is not in a singleton, it is only cycle free if the
1704 // other members are all phi nodes (as they do not compute anything, they are
1705 // copies).
1706 auto ICS = InstCycleState.lookup(I);
1707 if (ICS == ICS_Unknown) {
1708 SCCFinder.Start(I);
1709 auto &SCC = SCCFinder.getComponentFor(I);
1710 // It's cycle free if it's size 1 or the SCC is *only* phi nodes.
1711 if (SCC.size() == 1)
1712 InstCycleState.insert({I, ICS_CycleFree});
1713 else {
1714 bool AllPhis = llvm::all_of(SCC, [](const Value *V) {
1715 return isa<PHINode>(V) || isCopyOfAPHI(V);
1716 });
1717 ICS = AllPhis ? ICS_CycleFree : ICS_Cycle;
1718 for (auto *Member : SCC)
1719 if (auto *MemberPhi = dyn_cast<PHINode>(Member))
1720 InstCycleState.insert({MemberPhi, ICS});
1721 }
1722 }
1723 if (ICS == ICS_Cycle)
1724 return false;
1725 return true;
1726}
1727
1728// Evaluate PHI nodes symbolically and create an expression result.
1729const Expression *
1730NewGVN::performSymbolicPHIEvaluation(ArrayRef<ValPair> PHIOps,
1731 Instruction *I,
1732 BasicBlock *PHIBlock) const {
1733 // True if one of the incoming phi edges is a backedge.
1734 bool HasBackedge = false;
1735 // All constant tracks the state of whether all the *original* phi operands
1736 // This is really shorthand for "this phi cannot cycle due to forward
1737 // change in value of the phi is guaranteed not to later change the value of
1738 // the phi. IE it can't be v = phi(undef, v+1)
1739 bool OriginalOpsConstant = true;
1740 auto *E = cast<PHIExpression>(createPHIExpression(
20
Calling 'NewGVN::createPHIExpression'
1741 PHIOps, I, PHIBlock, HasBackedge, OriginalOpsConstant));
1742 // We match the semantics of SimplifyPhiNode from InstructionSimplify here.
1743 // See if all arguments are the same.
1744 // We track if any were undef because they need special handling.
1745 bool HasUndef = false;
1746 auto Filtered = make_filter_range(E->operands(), [&](Value *Arg) {
1747 if (isa<UndefValue>(Arg)) {
1748 HasUndef = true;
1749 return false;
1750 }
1751 return true;
1752 });
1753 // If we are left with no operands, it's dead.
1754 if (Filtered.begin() == Filtered.end()) {
1755 // If it has undef at this point, it means there are no-non-undef arguments,
1756 // and thus, the value of the phi node must be undef.
1757 if (HasUndef) {
1758 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)
1759 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)
1760 << " 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)
;
1761 return createConstantExpression(UndefValue::get(I->getType()));
1762 }
1763
1764 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)
;
1765 deleteExpression(E);
1766 return createDeadExpression();
1767 }
1768 Value *AllSameValue = *(Filtered.begin());
1769 ++Filtered.begin();
1770 // Can't use std::equal here, sadly, because filter.begin moves.
1771 if (llvm::all_of(Filtered, [&](Value *Arg) { return Arg == AllSameValue; })) {
1772 // In LLVM's non-standard representation of phi nodes, it's possible to have
1773 // phi nodes with cycles (IE dependent on other phis that are .... dependent
1774 // on the original phi node), especially in weird CFG's where some arguments
1775 // are unreachable, or uninitialized along certain paths. This can cause
1776 // infinite loops during evaluation. We work around this by not trying to
1777 // really evaluate them independently, but instead using a variable
1778 // expression to say if one is equivalent to the other.
1779 // We also special case undef, so that if we have an undef, we can't use the
1780 // common value unless it dominates the phi block.
1781 if (HasUndef) {
1782 // If we have undef and at least one other value, this is really a
1783 // multivalued phi, and we need to know if it's cycle free in order to
1784 // evaluate whether we can ignore the undef. The other parts of this are
1785 // just shortcuts. If there is no backedge, or all operands are
1786 // constants, it also must be cycle free.
1787 if (HasBackedge && !OriginalOpsConstant &&
1788 !isa<UndefValue>(AllSameValue) && !isCycleFree(I))
1789 return E;
1790
1791 // Only have to check for instructions
1792 if (auto *AllSameInst = dyn_cast<Instruction>(AllSameValue))
1793 if (!someEquivalentDominates(AllSameInst, I))
1794 return E;
1795 }
1796 // Can't simplify to something that comes later in the iteration.
1797 // Otherwise, when and if it changes congruence class, we will never catch
1798 // up. We will always be a class behind it.
1799 if (isa<Instruction>(AllSameValue) &&
1800 InstrToDFSNum(AllSameValue) > InstrToDFSNum(I))
1801 return E;
1802 NumGVNPhisAllSame++;
1803 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)
1804 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Simplified PHI node " <<
*I << " to " << *AllSameValue << "\n"; } }
while (false)
;
1805 deleteExpression(E);
1806 return createVariableOrConstant(AllSameValue);
1807 }
1808 return E;
1809}
1810
1811const Expression *
1812NewGVN::performSymbolicAggrValueEvaluation(Instruction *I) const {
1813 if (auto *EI = dyn_cast<ExtractValueInst>(I)) {
1814 auto *II = dyn_cast<IntrinsicInst>(EI->getAggregateOperand());
1815 if (II && EI->getNumIndices() == 1 && *EI->idx_begin() == 0) {
1816 unsigned Opcode = 0;
1817 // EI might be an extract from one of our recognised intrinsics. If it
1818 // is we'll synthesize a semantically equivalent expression instead on
1819 // an extract value expression.
1820 switch (II->getIntrinsicID()) {
1821 case Intrinsic::sadd_with_overflow:
1822 case Intrinsic::uadd_with_overflow:
1823 Opcode = Instruction::Add;
1824 break;
1825 case Intrinsic::ssub_with_overflow:
1826 case Intrinsic::usub_with_overflow:
1827 Opcode = Instruction::Sub;
1828 break;
1829 case Intrinsic::smul_with_overflow:
1830 case Intrinsic::umul_with_overflow:
1831 Opcode = Instruction::Mul;
1832 break;
1833 default:
1834 break;
1835 }
1836
1837 if (Opcode != 0) {
1838 // Intrinsic recognized. Grab its args to finish building the
1839 // expression.
1840 assert(II->getNumArgOperands() == 2 &&((II->getNumArgOperands() == 2 && "Expect two args for recognised intrinsics."
) ? static_cast<void> (0) : __assert_fail ("II->getNumArgOperands() == 2 && \"Expect two args for recognised intrinsics.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1841, __PRETTY_FUNCTION__))
1841 "Expect two args for recognised intrinsics.")((II->getNumArgOperands() == 2 && "Expect two args for recognised intrinsics."
) ? static_cast<void> (0) : __assert_fail ("II->getNumArgOperands() == 2 && \"Expect two args for recognised intrinsics.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1841, __PRETTY_FUNCTION__))
;
1842 return createBinaryExpression(Opcode, EI->getType(),
1843 II->getArgOperand(0),
1844 II->getArgOperand(1), I);
1845 }
1846 }
1847 }
1848
1849 return createAggregateValueExpression(I);
1850}
1851
1852const Expression *NewGVN::performSymbolicCmpEvaluation(Instruction *I) const {
1853 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 1853, __PRETTY_FUNCTION__))
;
1854
1855 auto *CI = cast<CmpInst>(I);
1856 // See if our operands are equal to those of a previous predicate, and if so,
1857 // if it implies true or false.
1858 auto Op0 = lookupOperandLeader(CI->getOperand(0));
1859 auto Op1 = lookupOperandLeader(CI->getOperand(1));
1860 auto OurPredicate = CI->getPredicate();
1861 if (shouldSwapOperands(Op0, Op1)) {
1862 std::swap(Op0, Op1);
1863 OurPredicate = CI->getSwappedPredicate();
1864 }
1865
1866 // Avoid processing the same info twice.
1867 const PredicateBase *LastPredInfo = nullptr;
1868 // See if we know something about the comparison itself, like it is the target
1869 // of an assume.
1870 auto *CmpPI = PredInfo->getPredicateInfoFor(I);
1871 if (dyn_cast_or_null<PredicateAssume>(CmpPI))
1872 return createConstantExpression(ConstantInt::getTrue(CI->getType()));
1873
1874 if (Op0 == Op1) {
1875 // This condition does not depend on predicates, no need to add users
1876 if (CI->isTrueWhenEqual())
1877 return createConstantExpression(ConstantInt::getTrue(CI->getType()));
1878 else if (CI->isFalseWhenEqual())
1879 return createConstantExpression(ConstantInt::getFalse(CI->getType()));
1880 }
1881
1882 // NOTE: Because we are comparing both operands here and below, and using
1883 // previous comparisons, we rely on fact that predicateinfo knows to mark
1884 // comparisons that use renamed operands as users of the earlier comparisons.
1885 // It is *not* enough to just mark predicateinfo renamed operands as users of
1886 // the earlier comparisons, because the *other* operand may have changed in a
1887 // previous iteration.
1888 // Example:
1889 // icmp slt %a, %b
1890 // %b.0 = ssa.copy(%b)
1891 // false branch:
1892 // icmp slt %c, %b.0
1893
1894 // %c and %a may start out equal, and thus, the code below will say the second
1895 // %icmp is false. c may become equal to something else, and in that case the
1896 // %second icmp *must* be reexamined, but would not if only the renamed
1897 // %operands are considered users of the icmp.
1898
1899 // *Currently* we only check one level of comparisons back, and only mark one
1900 // level back as touched when changes happen. If you modify this code to look
1901 // back farther through comparisons, you *must* mark the appropriate
1902 // comparisons as users in PredicateInfo.cpp, or you will cause bugs. See if
1903 // we know something just from the operands themselves
1904
1905 // See if our operands have predicate info, so that we may be able to derive
1906 // something from a previous comparison.
1907 for (const auto &Op : CI->operands()) {
1908 auto *PI = PredInfo->getPredicateInfoFor(Op);
1909 if (const auto *PBranch = dyn_cast_or_null<PredicateBranch>(PI)) {
1910 if (PI == LastPredInfo)
1911 continue;
1912 LastPredInfo = PI;
1913 // In phi of ops cases, we may have predicate info that we are evaluating
1914 // in a different context.
1915 if (!DT->dominates(PBranch->To, getBlockForValue(I)))
1916 continue;
1917 // TODO: Along the false edge, we may know more things too, like
1918 // icmp of
1919 // same operands is false.
1920 // TODO: We only handle actual comparison conditions below, not
1921 // and/or.
1922 auto *BranchCond = dyn_cast<CmpInst>(PBranch->Condition);
1923 if (!BranchCond)
1924 continue;
1925 auto *BranchOp0 = lookupOperandLeader(BranchCond->getOperand(0));
1926 auto *BranchOp1 = lookupOperandLeader(BranchCond->getOperand(1));
1927 auto BranchPredicate = BranchCond->getPredicate();
1928 if (shouldSwapOperands(BranchOp0, BranchOp1)) {
1929 std::swap(BranchOp0, BranchOp1);
1930 BranchPredicate = BranchCond->getSwappedPredicate();
1931 }
1932 if (BranchOp0 == Op0 && BranchOp1 == Op1) {
1933 if (PBranch->TrueEdge) {
1934 // If we know the previous predicate is true and we are in the true
1935 // edge then we may be implied true or false.
1936 if (CmpInst::isImpliedTrueByMatchingCmp(BranchPredicate,
1937 OurPredicate)) {
1938 addPredicateUsers(PI, I);
1939 return createConstantExpression(
1940 ConstantInt::getTrue(CI->getType()));
1941 }
1942
1943 if (CmpInst::isImpliedFalseByMatchingCmp(BranchPredicate,
1944 OurPredicate)) {
1945 addPredicateUsers(PI, I);
1946 return createConstantExpression(
1947 ConstantInt::getFalse(CI->getType()));
1948 }
1949 } else {
1950 // Just handle the ne and eq cases, where if we have the same
1951 // operands, we may know something.
1952 if (BranchPredicate == OurPredicate) {
1953 addPredicateUsers(PI, I);
1954 // Same predicate, same ops,we know it was false, so this is false.
1955 return createConstantExpression(
1956 ConstantInt::getFalse(CI->getType()));
1957 } else if (BranchPredicate ==
1958 CmpInst::getInversePredicate(OurPredicate)) {
1959 addPredicateUsers(PI, I);
1960 // Inverse predicate, we know the other was false, so this is true.
1961 return createConstantExpression(
1962 ConstantInt::getTrue(CI->getType()));
1963 }
1964 }
1965 }
1966 }
1967 }
1968 // Create expression will take care of simplifyCmpInst
1969 return createExpression(I);
1970}
1971
1972// Substitute and symbolize the value before value numbering.
1973const Expression *
1974NewGVN::performSymbolicEvaluation(Value *V,
1975 SmallPtrSetImpl<Value *> &Visited) const {
1976 const Expression *E = nullptr;
1977 if (auto *C = dyn_cast<Constant>(V))
1978 E = createConstantExpression(C);
1979 else if (isa<Argument>(V) || isa<GlobalVariable>(V)) {
1980 E = createVariableExpression(V);
1981 } else {
1982 // TODO: memory intrinsics.
1983 // TODO: Some day, we should do the forward propagation and reassociation
1984 // parts of the algorithm.
1985 auto *I = cast<Instruction>(V);
1986 switch (I->getOpcode()) {
1987 case Instruction::ExtractValue:
1988 case Instruction::InsertValue:
1989 E = performSymbolicAggrValueEvaluation(I);
1990 break;
1991 case Instruction::PHI: {
1992 SmallVector<ValPair, 3> Ops;
1993 auto *PN = cast<PHINode>(I);
1994 for (unsigned i = 0; i < PN->getNumOperands(); ++i)
1995 Ops.push_back({PN->getIncomingValue(i), PN->getIncomingBlock(i)});
1996 // Sort to ensure the invariant createPHIExpression requires is met.
1997 sortPHIOps(Ops);
1998 E = performSymbolicPHIEvaluation(Ops, I, getBlockForValue(I));
1999 } break;
2000 case Instruction::Call:
2001 E = performSymbolicCallEvaluation(I);
2002 break;
2003 case Instruction::Store:
2004 E = performSymbolicStoreEvaluation(I);
2005 break;
2006 case Instruction::Load:
2007 E = performSymbolicLoadEvaluation(I);
2008 break;
2009 case Instruction::BitCast:
2010 E = createExpression(I);
2011 break;
2012 case Instruction::ICmp:
2013 case Instruction::FCmp:
2014 E = performSymbolicCmpEvaluation(I);
2015 break;
2016 case Instruction::Add:
2017 case Instruction::FAdd:
2018 case Instruction::Sub:
2019 case Instruction::FSub:
2020 case Instruction::Mul:
2021 case Instruction::FMul:
2022 case Instruction::UDiv:
2023 case Instruction::SDiv:
2024 case Instruction::FDiv:
2025 case Instruction::URem:
2026 case Instruction::SRem:
2027 case Instruction::FRem:
2028 case Instruction::Shl:
2029 case Instruction::LShr:
2030 case Instruction::AShr:
2031 case Instruction::And:
2032 case Instruction::Or:
2033 case Instruction::Xor:
2034 case Instruction::Trunc:
2035 case Instruction::ZExt:
2036 case Instruction::SExt:
2037 case Instruction::FPToUI:
2038 case Instruction::FPToSI:
2039 case Instruction::UIToFP:
2040 case Instruction::SIToFP:
2041 case Instruction::FPTrunc:
2042 case Instruction::FPExt:
2043 case Instruction::PtrToInt:
2044 case Instruction::IntToPtr:
2045 case Instruction::Select:
2046 case Instruction::ExtractElement:
2047 case Instruction::InsertElement:
2048 case Instruction::ShuffleVector:
2049 case Instruction::GetElementPtr:
2050 E = createExpression(I);
2051 break;
2052 default:
2053 return nullptr;
2054 }
2055 }
2056 return E;
2057}
2058
2059// Look up a container in a map, and then call a function for each thing in the
2060// found container.
2061template <typename Map, typename KeyType, typename Func>
2062void NewGVN::for_each_found(Map &M, const KeyType &Key, Func F) {
2063 const auto Result = M.find_as(Key);
2064 if (Result != M.end())
2065 for (typename Map::mapped_type::value_type Mapped : Result->second)
2066 F(Mapped);
2067}
2068
2069// Look up a container of values/instructions in a map, and touch all the
2070// instructions in the container. Then erase value from the map.
2071template <typename Map, typename KeyType>
2072void NewGVN::touchAndErase(Map &M, const KeyType &Key) {
2073 const auto Result = M.find_as(Key);
2074 if (Result != M.end()) {
2075 for (const typename Map::mapped_type::value_type Mapped : Result->second)
2076 TouchedInstructions.set(InstrToDFSNum(Mapped));
2077 M.erase(Result);
2078 }
2079}
2080
2081void NewGVN::addAdditionalUsers(Value *To, Value *User) const {
2082 assert(User && To != User)((User && To != User) ? static_cast<void> (0) :
__assert_fail ("User && To != User", "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2082, __PRETTY_FUNCTION__))
;
2083 if (isa<Instruction>(To))
2084 AdditionalUsers[To].insert(User);
2085}
2086
2087void NewGVN::markUsersTouched(Value *V) {
2088 // Now mark the users as touched.
2089 for (auto *User : V->users()) {
2090 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2090, __PRETTY_FUNCTION__))
;
2091 TouchedInstructions.set(InstrToDFSNum(User));
2092 }
2093 touchAndErase(AdditionalUsers, V);
2094}
2095
2096void NewGVN::addMemoryUsers(const MemoryAccess *To, MemoryAccess *U) const {
2097 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
)
;
2098 MemoryToUsers[To].insert(U);
2099}
2100
2101void NewGVN::markMemoryDefTouched(const MemoryAccess *MA) {
2102 TouchedInstructions.set(MemoryToDFSNum(MA));
2103}
2104
2105void NewGVN::markMemoryUsersTouched(const MemoryAccess *MA) {
2106 if (isa<MemoryUse>(MA))
2107 return;
2108 for (auto U : MA->users())
2109 TouchedInstructions.set(MemoryToDFSNum(U));
2110 touchAndErase(MemoryToUsers, MA);
2111}
2112
2113// Add I to the set of users of a given predicate.
2114void NewGVN::addPredicateUsers(const PredicateBase *PB, Instruction *I) const {
2115 // Don't add temporary instructions to the user lists.
2116 if (AllTempInstructions.count(I))
2117 return;
2118
2119 if (auto *PBranch = dyn_cast<PredicateBranch>(PB))
2120 PredicateToUsers[PBranch->Condition].insert(I);
2121 else if (auto *PAssume = dyn_cast<PredicateBranch>(PB))
2122 PredicateToUsers[PAssume->Condition].insert(I);
2123}
2124
2125// Touch all the predicates that depend on this instruction.
2126void NewGVN::markPredicateUsersTouched(Instruction *I) {
2127 touchAndErase(PredicateToUsers, I);
2128}
2129
2130// Mark users affected by a memory leader change.
2131void NewGVN::markMemoryLeaderChangeTouched(CongruenceClass *CC) {
2132 for (auto M : CC->memory())
2133 markMemoryDefTouched(M);
2134}
2135
2136// Touch the instructions that need to be updated after a congruence class has a
2137// leader change, and mark changed values.
2138void NewGVN::markValueLeaderChangeTouched(CongruenceClass *CC) {
2139 for (auto M : *CC) {
2140 if (auto *I = dyn_cast<Instruction>(M))
2141 TouchedInstructions.set(InstrToDFSNum(I));
2142 LeaderChanges.insert(M);
2143 }
2144}
2145
2146// Give a range of things that have instruction DFS numbers, this will return
2147// the member of the range with the smallest dfs number.
2148template <class T, class Range>
2149T *NewGVN::getMinDFSOfRange(const Range &R) const {
2150 std::pair<T *, unsigned> MinDFS = {nullptr, ~0U};
2151 for (const auto X : R) {
2152 auto DFSNum = InstrToDFSNum(X);
2153 if (DFSNum < MinDFS.second)
2154 MinDFS = {X, DFSNum};
2155 }
2156 return MinDFS.first;
2157}
2158
2159// This function returns the MemoryAccess that should be the next leader of
2160// congruence class CC, under the assumption that the current leader is going to
2161// disappear.
2162const MemoryAccess *NewGVN::getNextMemoryLeader(CongruenceClass *CC) const {
2163 // TODO: If this ends up to slow, we can maintain a next memory leader like we
2164 // do for regular leaders.
2165 // Make sure there will be a leader to find.
2166 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2166, __PRETTY_FUNCTION__))
;
2167 if (CC->getStoreCount() > 0) {
2168 if (auto *NL = dyn_cast_or_null<StoreInst>(CC->getNextLeader().first))
2169 return getMemoryAccess(NL);
2170 // Find the store with the minimum DFS number.
2171 auto *V = getMinDFSOfRange<Value>(make_filter_range(
2172 *CC, [&](const Value *V) { return isa<StoreInst>(V); }));
2173 return getMemoryAccess(cast<StoreInst>(V));
2174 }
2175 assert(CC->getStoreCount() == 0)((CC->getStoreCount() == 0) ? static_cast<void> (0) :
__assert_fail ("CC->getStoreCount() == 0", "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2175, __PRETTY_FUNCTION__))
;
2176
2177 // Given our assertion, hitting this part must mean
2178 // !OldClass->memory_empty()
2179 if (CC->memory_size() == 1)
2180 return *CC->memory_begin();
2181 return getMinDFSOfRange<const MemoryPhi>(CC->memory());
2182}
2183
2184// This function returns the next value leader of a congruence class, under the
2185// assumption that the current leader is going away. This should end up being
2186// the next most dominating member.
2187Value *NewGVN::getNextValueLeader(CongruenceClass *CC) const {
2188 // We don't need to sort members if there is only 1, and we don't care about
2189 // sorting the TOP class because everything either gets out of it or is
2190 // unreachable.
2191
2192 if (CC->size() == 1 || CC == TOPClass) {
2193 return *(CC->begin());
2194 } else if (CC->getNextLeader().first) {
2195 ++NumGVNAvoidedSortedLeaderChanges;
2196 return CC->getNextLeader().first;
2197 } else {
2198 ++NumGVNSortedLeaderChanges;
2199 // NOTE: If this ends up to slow, we can maintain a dual structure for
2200 // member testing/insertion, or keep things mostly sorted, and sort only
2201 // here, or use SparseBitVector or ....
2202 return getMinDFSOfRange<Value>(*CC);
2203 }
2204}
2205
2206// Move a MemoryAccess, currently in OldClass, to NewClass, including updates to
2207// the memory members, etc for the move.
2208//
2209// The invariants of this function are:
2210//
2211// - I must be moving to NewClass from OldClass
2212// - The StoreCount of OldClass and NewClass is expected to have been updated
2213// for I already if it is a store.
2214// - The OldClass memory leader has not been updated yet if I was the leader.
2215void NewGVN::moveMemoryToNewCongruenceClass(Instruction *I,
2216 MemoryAccess *InstMA,
2217 CongruenceClass *OldClass,
2218 CongruenceClass *NewClass) {
2219 // If the leader is I, and we had a representative MemoryAccess, it should
2220 // be the MemoryAccess of OldClass.
2221 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2225, __PRETTY_FUNCTION__))
2222 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2225, __PRETTY_FUNCTION__))
2223 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2225, __PRETTY_FUNCTION__))
2224 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2225, __PRETTY_FUNCTION__))
2225 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2225, __PRETTY_FUNCTION__))
;
2226 // First, see what happens to the new class
2227 if (!NewClass->getMemoryLeader()) {
2228 // Should be a new class, or a store becoming a leader of a new class.
2229 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2230, __PRETTY_FUNCTION__))
2230 (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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2230, __PRETTY_FUNCTION__))
;
2231 NewClass->setMemoryLeader(InstMA);
2232 // Mark it touched if we didn't just create a singleton
2233 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)
2234 << 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)
2235 << " 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)
;
2236 markMemoryLeaderChangeTouched(NewClass);
2237 }
2238 setMemoryClass(InstMA, NewClass);
2239 // Now, fixup the old class if necessary
2240 if (OldClass->getMemoryLeader() == InstMA) {
2241 if (!OldClass->definesNoMemory()) {
2242 OldClass->setMemoryLeader(getNextMemoryLeader(OldClass));
2243 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)
2244 << 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)
2245 << *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)
2246 << " 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)
;
2247 markMemoryLeaderChangeTouched(OldClass);
2248 } else
2249 OldClass->setMemoryLeader(nullptr);
2250 }
2251}
2252
2253// Move a value, currently in OldClass, to be part of NewClass
2254// Update OldClass and NewClass for the move (including changing leaders, etc).
2255void NewGVN::moveValueToNewCongruenceClass(Instruction *I, const Expression *E,
2256 CongruenceClass *OldClass,
2257 CongruenceClass *NewClass) {
2258 if (I == OldClass->getNextLeader().first)
2259 OldClass->resetNextLeader();
2260
2261 OldClass->erase(I);
2262 NewClass->insert(I);
2263
2264 if (NewClass->getLeader() != I)
2265 NewClass->addPossibleNextLeader({I, InstrToDFSNum(I)});
2266 // Handle our special casing of stores.
2267 if (auto *SI = dyn_cast<StoreInst>(I)) {
2268 OldClass->decStoreCount();
2269 // Okay, so when do we want to make a store a leader of a class?
2270 // If we have a store defined by an earlier load, we want the earlier load
2271 // to lead the class.
2272 // If we have a store defined by something else, we want the store to lead
2273 // the class so everything else gets the "something else" as a value.
2274 // If we have a store as the single member of the class, we want the store
2275 // as the leader
2276 if (NewClass->getStoreCount() == 0 && !NewClass->getStoredValue()) {
2277 // If it's a store expression we are using, it means we are not equivalent
2278 // to something earlier.
2279 if (auto *SE = dyn_cast<StoreExpression>(E)) {
2280 NewClass->setStoredValue(SE->getStoredValue());
2281 markValueLeaderChangeTouched(NewClass);
2282 // Shift the new class leader to be the store
2283 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)
2284 << 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)
2285 << *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)
2286 << " 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)
;
2287 // If we changed the leader, we have to mark it changed because we don't
2288 // know what it will do to symbolic evaluation.
2289 NewClass->setLeader(SI);
2290 }
2291 // We rely on the code below handling the MemoryAccess change.
2292 }
2293 NewClass->incStoreCount();
2294 }
2295 // True if there is no memory instructions left in a class that had memory
2296 // instructions before.
2297
2298 // If it's not a memory use, set the MemoryAccess equivalence
2299 auto *InstMA = dyn_cast_or_null<MemoryDef>(getMemoryAccess(I));
2300 if (InstMA)
2301 moveMemoryToNewCongruenceClass(I, InstMA, OldClass, NewClass);
2302 ValueToClass[I] = NewClass;
2303 // See if we destroyed the class or need to swap leaders.
2304 if (OldClass->empty() && OldClass != TOPClass) {
2305 if (OldClass->getDefiningExpr()) {
2306 LLVM_DEBUG(dbgs() << "Erasing expression " << *OldClass->getDefiningExpr()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Erasing expression " << *
OldClass->getDefiningExpr() << " from table\n"; } } while
(false)
2307 << " from table\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Erasing expression " << *
OldClass->getDefiningExpr() << " from table\n"; } } while
(false)
;
2308 // We erase it as an exact expression to make sure we don't just erase an
2309 // equivalent one.
2310 auto Iter = ExpressionToClass.find_as(
2311 ExactEqualsExpression(*OldClass->getDefiningExpr()));
2312 if (Iter != ExpressionToClass.end())
2313 ExpressionToClass.erase(Iter);
2314#ifdef EXPENSIVE_CHECKS
2315 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2317, __PRETTY_FUNCTION__))
2316 (*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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2317, __PRETTY_FUNCTION__))
2317 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2317, __PRETTY_FUNCTION__))
;
2318#endif
2319 }
2320 } else if (OldClass->getLeader() == I) {
2321 // When the leader changes, the value numbering of
2322 // everything may change due to symbolization changes, so we need to
2323 // reprocess.
2324 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
)
2325 << OldClass->getID() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Value class leader change for class "
<< OldClass->getID() << "\n"; } } while (false
)
;
2326 ++NumGVNLeaderChanges;
2327 // Destroy the stored value if there are no more stores to represent it.
2328 // Note that this is basically clean up for the expression removal that
2329 // happens below. If we remove stores from a class, we may leave it as a
2330 // class of equivalent memory phis.
2331 if (OldClass->getStoreCount() == 0) {
2332 if (OldClass->getStoredValue())
2333 OldClass->setStoredValue(nullptr);
2334 }
2335 OldClass->setLeader(getNextValueLeader(OldClass));
2336 OldClass->resetNextLeader();
2337 markValueLeaderChangeTouched(OldClass);
2338 }
2339}
2340
2341// For a given expression, mark the phi of ops instructions that could have
2342// changed as a result.
2343void NewGVN::markPhiOfOpsChanged(const Expression *E) {
2344 touchAndErase(ExpressionToPhiOfOps, E);
2345}
2346
2347// Perform congruence finding on a given value numbering expression.
2348void NewGVN::performCongruenceFinding(Instruction *I, const Expression *E) {
2349 // This is guaranteed to return something, since it will at least find
2350 // TOP.
2351
2352 CongruenceClass *IClass = ValueToClass.lookup(I);
2353 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2353, __PRETTY_FUNCTION__))
;
2354 // Dead classes should have been eliminated from the mapping.
2355 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2355, __PRETTY_FUNCTION__))
;
2356
2357 CongruenceClass *EClass = nullptr;
2358 if (const auto *VE = dyn_cast<VariableExpression>(E)) {
2359 EClass = ValueToClass.lookup(VE->getVariableValue());
2360 } else if (isa<DeadExpression>(E)) {
2361 EClass = TOPClass;
2362 }
2363 if (!EClass) {
2364 auto lookupResult = ExpressionToClass.insert({E, nullptr});
2365
2366 // If it's not in the value table, create a new congruence class.
2367 if (lookupResult.second) {
2368 CongruenceClass *NewClass = createCongruenceClass(nullptr, E);
2369 auto place = lookupResult.first;
2370 place->second = NewClass;
2371
2372 // Constants and variables should always be made the leader.
2373 if (const auto *CE = dyn_cast<ConstantExpression>(E)) {
2374 NewClass->setLeader(CE->getConstantValue());
2375 } else if (const auto *SE = dyn_cast<StoreExpression>(E)) {
2376 StoreInst *SI = SE->getStoreInst();
2377 NewClass->setLeader(SI);
2378 NewClass->setStoredValue(SE->getStoredValue());
2379 // The RepMemoryAccess field will be filled in properly by the
2380 // moveValueToNewCongruenceClass call.
2381 } else {
2382 NewClass->setLeader(I);
2383 }
2384 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2385, __PRETTY_FUNCTION__))
2385 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2385, __PRETTY_FUNCTION__))
;
2386
2387 EClass = NewClass;
2388 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)
2389 << " 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)
2390 << 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)
2391 << *(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)
;
2392 if (NewClass->getStoredValue())
2393 LLVM_DEBUG(dbgs() << " and stored value "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " and stored value " << *
(NewClass->getStoredValue()); } } while (false)
2394 << *(NewClass->getStoredValue()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " and stored value " << *
(NewClass->getStoredValue()); } } while (false)
;
2395 LLVM_DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "\n"; } } while (false)
;
2396 } else {
2397 EClass = lookupResult.first->second;
2398 if (isa<ConstantExpression>(E))
2399 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2403, __PRETTY_FUNCTION__))
2400 (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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2403, __PRETTY_FUNCTION__))
2401 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2403, __PRETTY_FUNCTION__))
2402 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2403, __PRETTY_FUNCTION__))
2403 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2403, __PRETTY_FUNCTION__))
;
2404
2405 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2405, __PRETTY_FUNCTION__))
;
2406
2407 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 2407, __PRETTY_FUNCTION__))
;
2408 }
2409 }
2410 bool ClassChanged = IClass != EClass;
2411 bool LeaderChanged = LeaderChanges.erase(I);
2412 if (ClassChanged || LeaderChanged) {
2413 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)
2414 << *E << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "New class " << EClass->
getID() << " for expression " << *E << "\n"
; } } while (false)
;
2415 if (ClassChanged) {
2416 moveValueToNewCongruenceClass(I, E, IClass, EClass);
2417 markPhiOfOpsChanged(E);
2418 }
2419
2420 markUsersTouched(I);
2421 if (MemoryAccess *MA = getMemoryAccess(I))
2422 markMemoryUsersTouched(MA);
2423 if (auto *CI = dyn_cast<CmpInst>(I))
2424 markPredicateUsersTouched(CI);
2425 }
2426 // If we changed the class of the store, we want to ensure nothing finds the
2427 // old store expression. In particular, loads do not compare against stored
2428 // value, so they will find old store expressions (and associated class
2429 // mappings) if we leave them in the table.
2430 if (ClassChanged && isa<StoreInst>(I)) {
2431 auto *OldE = ValueToExpression.lookup(I);
2432 // It could just be that the old class died. We don't want to erase it if we
2433 // just moved classes.
2434 if (OldE && isa<StoreExpression>(OldE) && *E != *OldE) {
2435 // Erase this as an exact expression to ensure we don't erase expressions
2436 // equivalent to it.
2437 auto Iter = ExpressionToClass.find_as(ExactEqualsExpression(*OldE));
2438 if (Iter != ExpressionToClass.end())
2439 ExpressionToClass.erase(Iter);
2440 }
2441 }
2442 ValueToExpression[I] = E;
2443}
2444
2445// Process the fact that Edge (from, to) is reachable, including marking
2446// any newly reachable blocks and instructions for processing.
2447void NewGVN::updateReachableEdge(BasicBlock *From, BasicBlock *To) {
2448 // Check if the Edge was reachable before.
2449 if (ReachableEdges.insert({From, To}).second) {
2450 // If this block wasn't reachable before, all instructions are touched.
2451 if (ReachableBlocks.insert(To).second) {
2452 LLVM_DEBUG(dbgs() << "Block " << getBlockName(To)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " marked reachable\n"; } } while (false)
2453 << " marked reachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
To) << " marked reachable\n"; } } while (false)
;
2454 const auto &InstRange = BlockInstRange.lookup(To);
2455 TouchedInstructions.set(InstRange.first, InstRange.second);
2456 } else {
2457 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)
2458 << " 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)
2459 << 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)
2460 << "} 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)
;
2461
2462 // We've made an edge reachable to an existing block, which may
2463 // impact predicates. Otherwise, only mark the phi nodes as touched, as
2464 // they are the only thing that depend on new edges. Anything using their
2465 // values will get propagated to if necessary.
2466 if (MemoryAccess *MemPhi = getMemoryAccess(To))
2467 TouchedInstructions.set(InstrToDFSNum(MemPhi));
2468
2469 // FIXME: We should just add a union op on a Bitvector and
2470 // SparseBitVector. We can do it word by word faster than we are doing it
2471 // here.
2472 for (auto InstNum : RevisitOnReachabilityChange[To])
2473 TouchedInstructions.set(InstNum);
2474 }
2475 }
2476}
2477
2478// Given a predicate condition (from a switch, cmp, or whatever) and a block,
2479// see if we know some constant value for it already.
2480Value *NewGVN::findConditionEquivalence(Value *Cond) const {
2481 auto Result = lookupOperandLeader(Cond);
2482 return isa<Constant>(Result) ? Result : nullptr;
2483}
2484
2485// Process the outgoing edges of a block for reachability.
2486void NewGVN::processOutgoingEdges(Instruction *TI, BasicBlock *B) {
2487 // Evaluate reachability of terminator instruction.
2488 BranchInst *BR;
2489 if ((BR = dyn_cast<BranchInst>(TI)) && BR->isConditional()) {
2490 Value *Cond = BR->getCondition();
2491 Value *CondEvaluated = findConditionEquivalence(Cond);
2492 if (!CondEvaluated) {
2493 if (auto *I = dyn_cast<Instruction>(Cond)) {
2494 const Expression *E = createExpression(I);
2495 if (const auto *CE = dyn_cast<ConstantExpression>(E)) {
2496 CondEvaluated = CE->getConstantValue();
2497 }
2498 } else if (isa<ConstantInt>(Cond)) {
2499 CondEvaluated = Cond;
2500 }
2501 }
2502 ConstantInt *CI;
2503 BasicBlock *TrueSucc = BR->getSuccessor(0);
2504 BasicBlock *FalseSucc = BR->getSuccessor(1);
2505 if (CondEvaluated && (CI = dyn_cast<ConstantInt>(CondEvaluated))) {
2506 if (CI->isOne()) {
2507 LLVM_DEBUG(dbgs() << "Condition for Terminator " << *TIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to true\n"; } } while (false)
2508 << " evaluated to true\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to true\n"; } } while (false)
;
2509 updateReachableEdge(B, TrueSucc);
2510 } else if (CI->isZero()) {
2511 LLVM_DEBUG(dbgs() << "Condition for Terminator " << *TIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to false\n"; } } while (false)
2512 << " evaluated to false\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Condition for Terminator " <<
*TI << " evaluated to false\n"; } } while (false)
;
2513 updateReachableEdge(B, FalseSucc);
2514 }
2515 } else {
2516 updateReachableEdge(B, TrueSucc);
2517 updateReachableEdge(B, FalseSucc);
2518 }
2519 } else if (auto *SI = dyn_cast<SwitchInst>(TI)) {
2520 // For switches, propagate the case values into the case
2521 // destinations.
2522
2523 // Remember how many outgoing edges there are to every successor.
2524 SmallDenseMap<BasicBlock *, unsigned, 16> SwitchEdges;
2525
2526 Value *SwitchCond = SI->getCondition();
2527 Value *CondEvaluated = findConditionEquivalence(SwitchCond);
2528 // See if we were able to turn this switch statement into a constant.
2529 if (CondEvaluated && isa<ConstantInt>(CondEvaluated)) {
2530 auto *CondVal = cast<ConstantInt>(CondEvaluated);
2531 // We should be able to get case value for this.
2532 auto Case = *SI->findCaseValue(CondVal);
2533 if (Case.getCaseSuccessor() == SI->getDefaultDest()) {
2534 // We proved the value is outside of the range of the case.
2535 // We can't do anything other than mark the default dest as reachable,
2536 // and go home.
2537 updateReachableEdge(B, SI->getDefaultDest());
2538 return;
2539 }
2540 // Now get where it goes and mark it reachable.
2541 BasicBlock *TargetBlock = Case.getCaseSuccessor();
2542 updateReachableEdge(B, TargetBlock);
2543 } else {
2544 for (unsigned i = 0, e = SI->getNumSuccessors(); i != e; ++i) {
2545 BasicBlock *TargetBlock = SI->getSuccessor(i);
2546 ++SwitchEdges[TargetBlock];
2547 updateReachableEdge(B, TargetBlock);
2548 }
2549 }
2550 } else {
2551 // Otherwise this is either unconditional, or a type we have no
2552 // idea about. Just mark successors as reachable.
2553 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
2554 BasicBlock *TargetBlock = TI->getSuccessor(i);
2555 updateReachableEdge(B, TargetBlock);
2556 }
2557
2558 // This also may be a memory defining terminator, in which case, set it
2559 // equivalent only to itself.
2560 //
2561 auto *MA = getMemoryAccess(TI);
2562 if (MA && !isa<MemoryUse>(MA)) {
2563 auto *CC = ensureLeaderOfMemoryClass(MA);
2564 if (setMemoryClass(MA, CC))
2565 markMemoryUsersTouched(MA);
2566 }
2567 }
2568}
2569
2570// Remove the PHI of Ops PHI for I
2571void NewGVN::removePhiOfOps(Instruction *I, PHINode *PHITemp) {
2572 InstrDFS.erase(PHITemp);
2573 // It's still a temp instruction. We keep it in the array so it gets erased.
2574 // However, it's no longer used by I, or in the block
2575 TempToBlock.erase(PHITemp);
2576 RealToTemp.erase(I);
2577 // We don't remove the users from the phi node uses. This wastes a little
2578 // time, but such is life. We could use two sets to track which were there
2579 // are the start of NewGVN, and which were added, but right nowt he cost of
2580 // tracking is more than the cost of checking for more phi of ops.
2581}
2582
2583// Add PHI Op in BB as a PHI of operations version of ExistingValue.
2584void NewGVN::addPhiOfOps(PHINode *Op, BasicBlock *BB,
2585 Instruction *ExistingValue) {
2586 InstrDFS[Op] = InstrToDFSNum(ExistingValue);
2587 AllTempInstructions.insert(Op);
2588 TempToBlock[Op] = BB;
2589 RealToTemp[ExistingValue] = Op;
2590 // Add all users to phi node use, as they are now uses of the phi of ops phis
2591 // and may themselves be phi of ops.
2592 for (auto *U : ExistingValue->users())
2593 if (auto *UI = dyn_cast<Instruction>(U))
2594 PHINodeUses.insert(UI);
2595}
2596
2597static bool okayForPHIOfOps(const Instruction *I) {
2598 if (!EnablePhiOfOps)
2599 return false;
2600 return isa<BinaryOperator>(I) || isa<SelectInst>(I) || isa<CmpInst>(I) ||
2601 isa<LoadInst>(I);
2602}
2603
2604bool NewGVN::OpIsSafeForPHIOfOpsHelper(
2605 Value *V, const BasicBlock *PHIBlock,
2606 SmallPtrSetImpl<const Value *> &Visited,
2607 SmallVectorImpl<Instruction *> &Worklist) {
2608
2609 if (!isa<Instruction>(V))
2610 return true;
2611 auto OISIt = OpSafeForPHIOfOps.find(V);
2612 if (OISIt != OpSafeForPHIOfOps.end())
2613 return OISIt->second;
2614
2615 // Keep walking until we either dominate the phi block, or hit a phi, or run
2616 // out of things to check.
2617 if (DT->properlyDominates(getBlockForValue(V), PHIBlock)) {
2618 OpSafeForPHIOfOps.insert({V, true});
2619 return true;
2620 }
2621 // PHI in the same block.
2622 if (isa<PHINode>(V) && getBlockForValue(V) == PHIBlock) {
2623 OpSafeForPHIOfOps.insert({V, false});
2624 return false;
2625 }
2626
2627 auto *OrigI = cast<Instruction>(V);
2628 for (auto *Op : OrigI->operand_values()) {
2629 if (!isa<Instruction>(Op))
2630 continue;
2631 // Stop now if we find an unsafe operand.
2632 auto OISIt = OpSafeForPHIOfOps.find(OrigI);
2633 if (OISIt != OpSafeForPHIOfOps.end()) {
2634 if (!OISIt->second) {
2635 OpSafeForPHIOfOps.insert({V, false});
2636 return false;
2637 }
2638 continue;
2639 }
2640 if (!Visited.insert(Op).second)
2641 continue;
2642 Worklist.push_back(cast<Instruction>(Op));
2643 }
2644 return true;
2645}
2646
2647// Return true if this operand will be safe to use for phi of ops.
2648//
2649// The reason some operands are unsafe is that we are not trying to recursively
2650// translate everything back through phi nodes. We actually expect some lookups
2651// of expressions to fail. In particular, a lookup where the expression cannot
2652// exist in the predecessor. This is true even if the expression, as shown, can
2653// be determined to be constant.
2654bool NewGVN::OpIsSafeForPHIOfOps(Value *V, const BasicBlock *PHIBlock,
2655 SmallPtrSetImpl<const Value *> &Visited) {
2656 SmallVector<Instruction *, 4> Worklist;
2657 if (!OpIsSafeForPHIOfOpsHelper(V, PHIBlock, Visited, Worklist))
2658 return false;
2659 while (!Worklist.empty()) {
2660 auto *I = Worklist.pop_back_val();
2661 if (!OpIsSafeForPHIOfOpsHelper(I, PHIBlock, Visited, Worklist))
2662 return false;
2663 }
2664 OpSafeForPHIOfOps.insert({V, true});
2665 return true;
2666}
2667
2668// Try to find a leader for instruction TransInst, which is a phi translated
2669// version of something in our original program. Visited is used to ensure we
2670// don't infinite loop during translations of cycles. OrigInst is the
2671// instruction in the original program, and PredBB is the predecessor we
2672// translated it through.
2673Value *NewGVN::findLeaderForInst(Instruction *TransInst,
2674 SmallPtrSetImpl<Value *> &Visited,
2675 MemoryAccess *MemAccess, Instruction *OrigInst,
2676 BasicBlock *PredBB) {
2677 unsigned IDFSNum = InstrToDFSNum(OrigInst);
2678 // Make sure it's marked as a temporary instruction.
2679 AllTempInstructions.insert(TransInst);
2680 // and make sure anything that tries to add it's DFS number is
2681 // redirected to the instruction we are making a phi of ops
2682 // for.
2683 TempToBlock.insert({TransInst, PredBB});
2684 InstrDFS.insert({TransInst, IDFSNum});
2685
2686 const Expression *E = performSymbolicEvaluation(TransInst, Visited);
2687 InstrDFS.erase(TransInst);
2688 AllTempInstructions.erase(TransInst);
2689 TempToBlock.erase(TransInst);
2690 if (MemAccess)
2691 TempToMemory.erase(TransInst);
2692 if (!E)
2693 return nullptr;
2694 auto *FoundVal = findPHIOfOpsLeader(E, OrigInst, PredBB);
2695 if (!FoundVal) {
2696 ExpressionToPhiOfOps[E].insert(OrigInst);
2697 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)
2698 << " 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)
;
2699 return nullptr;
2700 }
2701 if (auto *SI = dyn_cast<StoreInst>(FoundVal))
2702 FoundVal = SI->getValueOperand();
2703 return FoundVal;
2704}
2705
2706// When we see an instruction that is an op of phis, generate the equivalent phi
2707// of ops form.
2708const Expression *
2709NewGVN::makePossiblePHIOfOps(Instruction *I,
2710 SmallPtrSetImpl<Value *> &Visited) {
2711 if (!okayForPHIOfOps(I))
1
Taking false branch
2712 return nullptr;
2713
2714 if (!Visited.insert(I).second)
2
Assuming the condition is false
3
Taking false branch
2715 return nullptr;
2716 // For now, we require the instruction be cycle free because we don't
2717 // *always* create a phi of ops for instructions that could be done as phi
2718 // of ops, we only do it if we think it is useful. If we did do it all the
2719 // time, we could remove the cycle free check.
2720 if (!isCycleFree(I))
4
Taking false branch
2721 return nullptr;
2722
2723 SmallPtrSet<const Value *, 8> ProcessedPHIs;
2724 // TODO: We don't do phi translation on memory accesses because it's
2725 // complicated. For a load, we'd need to be able to simulate a new memoryuse,
2726 // which we don't have a good way of doing ATM.
2727 auto *MemAccess = getMemoryAccess(I);
2728 // If the memory operation is defined by a memory operation this block that
2729 // isn't a MemoryPhi, transforming the pointer backwards through a scalar phi
2730 // can't help, as it would still be killed by that memory operation.
2731 if (MemAccess && !isa<MemoryPhi>(MemAccess->getDefiningAccess()) &&
5
Assuming the condition is false
6
Taking false branch
2732 MemAccess->getDefiningAccess()->getBlock() == I->getParent())
2733 return nullptr;
2734
2735 // Convert op of phis to phi of ops
2736 SmallPtrSet<const Value *, 10> VisitedOps;
2737 SmallVector<Value *, 4> Ops(I->operand_values());
2738 BasicBlock *SamePHIBlock = nullptr;
2739 PHINode *OpPHI = nullptr;
2740 if (!DebugCounter::shouldExecute(PHIOfOpsCounter))
7
Assuming the condition is false
8
Taking false branch
2741 return nullptr;
2742 for (auto *Op : Ops) {
9
Assuming '__begin1' is not equal to '__end1'
2743 if (!isa<PHINode>(Op)) {
10
Taking true branch
2744 auto *ValuePHI = RealToTemp.lookup(Op);
2745 if (!ValuePHI)
11
Assuming 'ValuePHI' is non-null
12
Taking false branch
2746 continue;
2747 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)
;
2748 Op = ValuePHI;
2749 }
2750 OpPHI = cast<PHINode>(Op);
2751 if (!SamePHIBlock) {
13
Taking true branch
2752 SamePHIBlock = getBlockForValue(OpPHI);
2753 } else if (SamePHIBlock != getBlockForValue(OpPHI)) {
2754 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHIs for operands are not all in the same block, aborting\n"
; } } while (false)
2755 dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "PHIs for operands are not all in the same block, aborting\n"
; } } while (false)
2756 << "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)
;
2757 return nullptr;
2758 }
2759 // No point in doing this for one-operand phis.
2760 if (OpPHI->getNumOperands() == 1) {
14
Assuming the condition is false
15
Taking false branch
2761 OpPHI = nullptr;
2762 continue;
2763 }
2764 }
2765
2766 if (!OpPHI)
16
Taking false branch
2767 return nullptr;
2768
2769 SmallVector<ValPair, 4> PHIOps;
2770 SmallPtrSet<Value *, 4> Deps;
2771 auto *PHIBlock = getBlockForValue(OpPHI);
2772 RevisitOnReachabilityChange[PHIBlock].reset(InstrToDFSNum(I));
2773 for (unsigned PredNum = 0; PredNum < OpPHI->getNumOperands(); ++PredNum) {
17
Assuming the condition is false
18
Loop condition is false. Execution continues on line 2835
2774 auto *PredBB = OpPHI->getIncomingBlock(PredNum);
2775 Value *FoundVal = nullptr;
2776 SmallPtrSet<Value *, 4> CurrentDeps;
2777 // We could just skip unreachable edges entirely but it's tricky to do
2778 // with rewriting existing phi nodes.
2779 if (ReachableEdges.count({PredBB, PHIBlock})) {
2780 // Clone the instruction, create an expression from it that is
2781 // translated back into the predecessor, and see if we have a leader.
2782 Instruction *ValueOp = I->clone();
2783 if (MemAccess)
2784 TempToMemory.insert({ValueOp, MemAccess});
2785 bool SafeForPHIOfOps = true;
2786 VisitedOps.clear();
2787 for (auto &Op : ValueOp->operands()) {
2788 auto *OrigOp = &*Op;
2789 // When these operand changes, it could change whether there is a
2790 // leader for us or not, so we have to add additional users.
2791 if (isa<PHINode>(Op)) {
2792 Op = Op->DoPHITranslation(PHIBlock, PredBB);
2793 if (Op != OrigOp && Op != I)
2794 CurrentDeps.insert(Op);
2795 } else if (auto *ValuePHI = RealToTemp.lookup(Op)) {
2796 if (getBlockForValue(ValuePHI) == PHIBlock)
2797 Op = ValuePHI->getIncomingValueForBlock(PredBB);
2798 }
2799 // If we phi-translated the op, it must be safe.
2800 SafeForPHIOfOps =
2801 SafeForPHIOfOps &&
2802 (Op != OrigOp || OpIsSafeForPHIOfOps(Op, PHIBlock, VisitedOps));
2803 }
2804 // FIXME: For those things that are not safe we could generate
2805 // expressions all the way down, and see if this comes out to a
2806 // constant. For anything where that is true, and unsafe, we should
2807 // have made a phi-of-ops (or value numbered it equivalent to something)
2808 // for the pieces already.
2809 FoundVal = !SafeForPHIOfOps ? nullptr
2810 : findLeaderForInst(ValueOp, Visited,
2811 MemAccess, I, PredBB);
2812 ValueOp->deleteValue();
2813 if (!FoundVal) {
2814 // We failed to find a leader for the current ValueOp, but this might
2815 // change in case of the translated operands change.
2816 if (SafeForPHIOfOps)
2817 for (auto Dep : CurrentDeps)
2818 addAdditionalUsers(Dep, I);
2819
2820 return nullptr;
2821 }
2822 Deps.insert(CurrentDeps.begin(), CurrentDeps.end());
2823 } else {
2824 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)
2825 << 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)
2826 << " 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)
;
2827 FoundVal = UndefValue::get(I->getType());
2828 RevisitOnReachabilityChange[PHIBlock].set(InstrToDFSNum(I));
2829 }
2830
2831 PHIOps.push_back({FoundVal, PredBB});
2832 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)
2833 << getBlockName(PredBB) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found phi of ops operand " <<
*FoundVal << " in " << getBlockName(PredBB) <<
"\n"; } } while (false)
;
2834 }
2835 for (auto Dep : Deps)
2836 addAdditionalUsers(Dep, I);
2837 sortPHIOps(PHIOps);
2838 auto *E = performSymbolicPHIEvaluation(PHIOps, I, PHIBlock);
19
Calling 'NewGVN::performSymbolicPHIEvaluation'
2839 if (isa<ConstantExpression>(E) || isa<VariableExpression>(E)) {
2840 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)
2841 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)
2842 << "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)
2843 "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)
;
2844 return E;
2845 }
2846 auto *ValuePHI = RealToTemp.lookup(I);
2847 bool NewPHI = false;
2848 if (!ValuePHI) {
2849 ValuePHI =
2850 PHINode::Create(I->getType(), OpPHI->getNumOperands(), "phiofops");
2851 addPhiOfOps(ValuePHI, PHIBlock, I);
2852 NewPHI = true;
2853 NumGVNPHIOfOpsCreated++;
2854 }
2855 if (NewPHI) {
2856 for (auto PHIOp : PHIOps)
2857 ValuePHI->addIncoming(PHIOp.first, PHIOp.second);
2858 } else {
2859 TempToBlock[ValuePHI] = PHIBlock;
2860 unsigned int i = 0;
2861 for (auto PHIOp : PHIOps) {
2862 ValuePHI->setIncomingValue(i, PHIOp.first);
2863 ValuePHI->setIncomingBlock(i, PHIOp.second);
2864 ++i;
2865 }
2866 }
2867 RevisitOnReachabilityChange[PHIBlock].set(InstrToDFSNum(I));
2868 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)
2869 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Created phi of ops " << *
ValuePHI << " for " << *I << "\n"; } } while
(false)
;
2870
2871 return E;
2872}
2873
2874// The algorithm initially places the values of the routine in the TOP
2875// congruence class. The leader of TOP is the undetermined value `undef`.
2876// When the algorithm has finished, values still in TOP are unreachable.
2877void NewGVN::initializeCongruenceClasses(Function &F) {
2878 NextCongruenceNum = 0;
2879
2880 // Note that even though we use the live on entry def as a representative
2881 // MemoryAccess, it is *not* the same as the actual live on entry def. We
2882 // have no real equivalemnt to undef for MemoryAccesses, and so we really
2883 // should be checking whether the MemoryAccess is top if we want to know if it
2884 // is equivalent to everything. Otherwise, what this really signifies is that
2885 // the access "it reaches all the way back to the beginning of the function"
2886
2887 // Initialize all other instructions to be in TOP class.
2888 TOPClass = createCongruenceClass(nullptr, nullptr);
2889 TOPClass->setMemoryLeader(MSSA->getLiveOnEntryDef());
2890 // The live on entry def gets put into it's own class
2891 MemoryAccessToClass[MSSA->getLiveOnEntryDef()] =
2892 createMemoryClass(MSSA->getLiveOnEntryDef());
2893
2894 for (auto DTN : nodes(DT)) {
2895 BasicBlock *BB = DTN->getBlock();
2896 // All MemoryAccesses are equivalent to live on entry to start. They must
2897 // be initialized to something so that initial changes are noticed. For
2898 // the maximal answer, we initialize them all to be the same as
2899 // liveOnEntry.
2900 auto *MemoryBlockDefs = MSSA->getBlockDefs(BB);
2901 if (MemoryBlockDefs)
2902 for (const auto &Def : *MemoryBlockDefs) {
2903 MemoryAccessToClass[&Def] = TOPClass;
2904 auto *MD = dyn_cast<MemoryDef>(&Def);
2905 // Insert the memory phis into the member list.
2906 if (!MD) {
2907 const MemoryPhi *MP = cast<MemoryPhi>(&Def);
2908 TOPClass->memory_insert(MP);
2909 MemoryPhiState.insert({MP, MPS_TOP});
2910 }
2911
2912 if (MD && isa<StoreInst>(MD->getMemoryInst()))
2913 TOPClass->incStoreCount();
2914 }
2915
2916 // FIXME: This is trying to discover which instructions are uses of phi
2917 // nodes. We should move this into one of the myriad of places that walk
2918 // all the operands already.
2919 for (auto &I : *BB) {
2920 if (isa<PHINode>(&I))
2921 for (auto *U : I.users())
2922 if (auto *UInst = dyn_cast<Instruction>(U))
2923 if (InstrToDFSNum(UInst) != 0 && okayForPHIOfOps(UInst))
2924 PHINodeUses.insert(UInst);
2925 // Don't insert void terminators into the class. We don't value number
2926 // them, and they just end up sitting in TOP.
2927 if (I.isTerminator() && I.getType()->isVoidTy())
2928 continue;
2929 TOPClass->insert(&I);
2930 ValueToClass[&I] = TOPClass;
2931 }
2932 }
2933
2934 // Initialize arguments to be in their own unique congruence classes
2935 for (auto &FA : F.args())
2936 createSingletonCongruenceClass(&FA);
2937}
2938
2939void NewGVN::cleanupTables() {
2940 for (unsigned i = 0, e = CongruenceClasses.size(); i != e; ++i) {
2941 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)
2942 << " 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)
2943 << " members\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Congruence class " << CongruenceClasses
[i]->getID() << " has " << CongruenceClasses[i
]->size() << " members\n"; } } while (false)
;
2944 // Make sure we delete the congruence class (probably worth switching to
2945 // a unique_ptr at some point.
2946 delete CongruenceClasses[i];
2947 CongruenceClasses[i] = nullptr;
2948 }
2949
2950 // Destroy the value expressions
2951 SmallVector<Instruction *, 8> TempInst(AllTempInstructions.begin(),
2952 AllTempInstructions.end());
2953 AllTempInstructions.clear();
2954
2955 // We have to drop all references for everything first, so there are no uses
2956 // left as we delete them.
2957 for (auto *I : TempInst) {
2958 I->dropAllReferences();
2959 }
2960
2961 while (!TempInst.empty()) {
2962 auto *I = TempInst.back();
2963 TempInst.pop_back();
2964 I->deleteValue();
2965 }
2966
2967 ValueToClass.clear();
2968 ArgRecycler.clear(ExpressionAllocator);
2969 ExpressionAllocator.Reset();
2970 CongruenceClasses.clear();
2971 ExpressionToClass.clear();
2972 ValueToExpression.clear();
2973 RealToTemp.clear();
2974 AdditionalUsers.clear();
2975 ExpressionToPhiOfOps.clear();
2976 TempToBlock.clear();
2977 TempToMemory.clear();
2978 PHINodeUses.clear();
2979 OpSafeForPHIOfOps.clear();
2980 ReachableBlocks.clear();
2981 ReachableEdges.clear();
2982#ifndef NDEBUG
2983 ProcessedCount.clear();
2984#endif
2985 InstrDFS.clear();
2986 InstructionsToErase.clear();
2987 DFSToInstr.clear();
2988 BlockInstRange.clear();
2989 TouchedInstructions.clear();
2990 MemoryAccessToClass.clear();
2991 PredicateToUsers.clear();
2992 MemoryToUsers.clear();
2993 RevisitOnReachabilityChange.clear();
2994}
2995
2996// Assign local DFS number mapping to instructions, and leave space for Value
2997// PHI's.
2998std::pair<unsigned, unsigned> NewGVN::assignDFSNumbers(BasicBlock *B,
2999 unsigned Start) {
3000 unsigned End = Start;
3001 if (MemoryAccess *MemPhi = getMemoryAccess(B)) {
3002 InstrDFS[MemPhi] = End++;
3003 DFSToInstr.emplace_back(MemPhi);
3004 }
3005
3006 // Then the real block goes next.
3007 for (auto &I : *B) {
3008 // There's no need to call isInstructionTriviallyDead more than once on
3009 // an instruction. Therefore, once we know that an instruction is dead
3010 // we change its DFS number so that it doesn't get value numbered.
3011 if (isInstructionTriviallyDead(&I, TLI)) {
3012 InstrDFS[&I] = 0;
3013 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)
;
3014 markInstructionForDeletion(&I);
3015 continue;
3016 }
3017 if (isa<PHINode>(&I))
3018 RevisitOnReachabilityChange[B].set(End);
3019 InstrDFS[&I] = End++;
3020 DFSToInstr.emplace_back(&I);
3021 }
3022
3023 // All of the range functions taken half-open ranges (open on the end side).
3024 // So we do not subtract one from count, because at this point it is one
3025 // greater than the last instruction.
3026 return std::make_pair(Start, End);
3027}
3028
3029void NewGVN::updateProcessedCount(const Value *V) {
3030#ifndef NDEBUG
3031 if (ProcessedCount.count(V) == 0) {
3032 ProcessedCount.insert({V, 1});
3033 } else {
3034 ++ProcessedCount[V];
3035 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3036, __PRETTY_FUNCTION__))
3036 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3036, __PRETTY_FUNCTION__))
;
3037 }
3038#endif
3039}
3040
3041// Evaluate MemoryPhi nodes symbolically, just like PHI nodes
3042void NewGVN::valueNumberMemoryPhi(MemoryPhi *MP) {
3043 // If all the arguments are the same, the MemoryPhi has the same value as the
3044 // argument. Filter out unreachable blocks and self phis from our operands.
3045 // TODO: We could do cycle-checking on the memory phis to allow valueizing for
3046 // self-phi checking.
3047 const BasicBlock *PHIBlock = MP->getBlock();
3048 auto Filtered = make_filter_range(MP->operands(), [&](const Use &U) {
3049 return cast<MemoryAccess>(U) != MP &&
3050 !isMemoryAccessTOP(cast<MemoryAccess>(U)) &&
3051 ReachableEdges.count({MP->getIncomingBlock(U), PHIBlock});
3052 });
3053 // If all that is left is nothing, our memoryphi is undef. We keep it as
3054 // InitialClass. Note: The only case this should happen is if we have at
3055 // least one self-argument.
3056 if (Filtered.begin() == Filtered.end()) {
3057 if (setMemoryClass(MP, TOPClass))
3058 markMemoryUsersTouched(MP);
3059 return;
3060 }
3061
3062 // Transform the remaining operands into operand leaders.
3063 // FIXME: mapped_iterator should have a range version.
3064 auto LookupFunc = [&](const Use &U) {
3065 return lookupMemoryLeader(cast<MemoryAccess>(U));
3066 };
3067 auto MappedBegin = map_iterator(Filtered.begin(), LookupFunc);
3068 auto MappedEnd = map_iterator(Filtered.end(), LookupFunc);
3069
3070 // and now check if all the elements are equal.
3071 // Sadly, we can't use std::equals since these are random access iterators.
3072 const auto *AllSameValue = *MappedBegin;
3073 ++MappedBegin;
3074 bool AllEqual = std::all_of(
3075 MappedBegin, MappedEnd,
3076 [&AllSameValue](const MemoryAccess *V) { return V == AllSameValue; });
3077
3078 if (AllEqual)
3079 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)
3080 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Memory Phi value numbered to "
<< *AllSameValue << "\n"; } } while (false)
;
3081 else
3082 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)
;
3083 // If it's equal to something, it's in that class. Otherwise, it has to be in
3084 // a class where it is the leader (other things may be equivalent to it, but
3085 // it needs to start off in its own class, which means it must have been the
3086 // leader, and it can't have stopped being the leader because it was never
3087 // removed).
3088 CongruenceClass *CC =
3089 AllEqual ? getMemoryClass(AllSameValue) : ensureLeaderOfMemoryClass(MP);
3090 auto OldState = MemoryPhiState.lookup(MP);
3091 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3091, __PRETTY_FUNCTION__))
;
3092 auto NewState = AllEqual ? MPS_Equivalent : MPS_Unique;
3093 MemoryPhiState[MP] = NewState;
3094 if (setMemoryClass(MP, CC) || OldState != NewState)
3095 markMemoryUsersTouched(MP);
3096}
3097
3098// Value number a single instruction, symbolically evaluating, performing
3099// congruence finding, and updating mappings.
3100void NewGVN::valueNumberInstruction(Instruction *I) {
3101 LLVM_DEBUG(dbgs() << "Processing instruction " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Processing instruction " <<
*I << "\n"; } } while (false)
;
3102 if (!I->isTerminator()) {
3103 const Expression *Symbolized = nullptr;
3104 SmallPtrSet<Value *, 2> Visited;
3105 if (DebugCounter::shouldExecute(VNCounter)) {
3106 Symbolized = performSymbolicEvaluation(I, Visited);
3107 // Make a phi of ops if necessary
3108 if (Symbolized && !isa<ConstantExpression>(Symbolized) &&
3109 !isa<VariableExpression>(Symbolized) && PHINodeUses.count(I)) {
3110 auto *PHIE = makePossiblePHIOfOps(I, Visited);
3111 // If we created a phi of ops, use it.
3112 // If we couldn't create one, make sure we don't leave one lying around
3113 if (PHIE) {
3114 Symbolized = PHIE;
3115 } else if (auto *Op = RealToTemp.lookup(I)) {
3116 removePhiOfOps(I, Op);
3117 }
3118 }
3119 } else {
3120 // Mark the instruction as unused so we don't value number it again.
3121 InstrDFS[I] = 0;
3122 }
3123 // If we couldn't come up with a symbolic expression, use the unknown
3124 // expression
3125 if (Symbolized == nullptr)
3126 Symbolized = createUnknownExpression(I);
3127 performCongruenceFinding(I, Symbolized);
3128 } else {
3129 // Handle terminators that return values. All of them produce values we
3130 // don't currently understand. We don't place non-value producing
3131 // terminators in a class.
3132 if (!I->getType()->isVoidTy()) {
3133 auto *Symbolized = createUnknownExpression(I);
3134 performCongruenceFinding(I, Symbolized);
3135 }
3136 processOutgoingEdges(I, I->getParent());
3137 }
3138}
3139
3140// Check if there is a path, using single or equal argument phi nodes, from
3141// First to Second.
3142bool NewGVN::singleReachablePHIPath(
3143 SmallPtrSet<const MemoryAccess *, 8> &Visited, const MemoryAccess *First,
3144 const MemoryAccess *Second) const {
3145 if (First == Second)
3146 return true;
3147 if (MSSA->isLiveOnEntryDef(First))
3148 return false;
3149
3150 // This is not perfect, but as we're just verifying here, we can live with
3151 // the loss of precision. The real solution would be that of doing strongly
3152 // connected component finding in this routine, and it's probably not worth
3153 // the complexity for the time being. So, we just keep a set of visited
3154 // MemoryAccess and return true when we hit a cycle.
3155 if (Visited.count(First))
3156 return true;
3157 Visited.insert(First);
3158
3159 const auto *EndDef = First;
3160 for (auto *ChainDef : optimized_def_chain(First)) {
3161 if (ChainDef == Second)
3162 return true;
3163 if (MSSA->isLiveOnEntryDef(ChainDef))
3164 return false;
3165 EndDef = ChainDef;
3166 }
3167 auto *MP = cast<MemoryPhi>(EndDef);
3168 auto ReachableOperandPred = [&](const Use &U) {
3169 return ReachableEdges.count({MP->getIncomingBlock(U), MP->getBlock()});
3170 };
3171 auto FilteredPhiArgs =
3172 make_filter_range(MP->operands(), ReachableOperandPred);
3173 SmallVector<const Value *, 32> OperandList;
3174 std::copy(FilteredPhiArgs.begin(), FilteredPhiArgs.end(),
3175 std::back_inserter(OperandList));
3176 bool Okay = is_splat(OperandList);
3177 if (Okay)
3178 return singleReachablePHIPath(Visited, cast<MemoryAccess>(OperandList[0]),
3179 Second);
3180 return false;
3181}
3182
3183// Verify the that the memory equivalence table makes sense relative to the
3184// congruence classes. Note that this checking is not perfect, and is currently
3185// subject to very rare false negatives. It is only useful for
3186// testing/debugging.
3187void NewGVN::verifyMemoryCongruency() const {
3188#ifndef NDEBUG
3189 // Verify that the memory table equivalence and memory member set match
3190 for (const auto *CC : CongruenceClasses) {
3191 if (CC == TOPClass || CC->isDead())
3192 continue;
3193 if (CC->getStoreCount() != 0) {
3194 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3196, __PRETTY_FUNCTION__))
3195 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3196, __PRETTY_FUNCTION__))
3196 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3196, __PRETTY_FUNCTION__))
;
3197 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3199, __PRETTY_FUNCTION__))
3198 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3199, __PRETTY_FUNCTION__))
3199 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3199, __PRETTY_FUNCTION__))
;
3200 }
3201
3202 if (CC->getMemoryLeader())
3203 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3205, __PRETTY_FUNCTION__))
3204 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3205, __PRETTY_FUNCTION__))
3205 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3205, __PRETTY_FUNCTION__))
;
3206 for (auto M : CC->memory())
3207 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3208, __PRETTY_FUNCTION__))
3208 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3208, __PRETTY_FUNCTION__))
;
3209 }
3210
3211 // Anything equivalent in the MemoryAccess table should be in the same
3212 // congruence class.
3213
3214 // Filter out the unreachable and trivially dead entries, because they may
3215 // never have been updated if the instructions were not processed.
3216 auto ReachableAccessPred =
3217 [&](const std::pair<const MemoryAccess *, CongruenceClass *> Pair) {
3218 bool Result = ReachableBlocks.count(Pair.first->getBlock());
3219 if (!Result || MSSA->isLiveOnEntryDef(Pair.first) ||
3220 MemoryToDFSNum(Pair.first) == 0)
3221 return false;
3222 if (auto *MemDef = dyn_cast<MemoryDef>(Pair.first))
3223 return !isInstructionTriviallyDead(MemDef->getMemoryInst());
3224
3225 // We could have phi nodes which operands are all trivially dead,
3226 // so we don't process them.
3227 if (auto *MemPHI = dyn_cast<MemoryPhi>(Pair.first)) {
3228 for (auto &U : MemPHI->incoming_values()) {
3229 if (auto *I = dyn_cast<Instruction>(&*U)) {
3230 if (!isInstructionTriviallyDead(I))
3231 return true;
3232 }
3233 }
3234 return false;
3235 }
3236
3237 return true;
3238 };
3239
3240 auto Filtered = make_filter_range(MemoryAccessToClass, ReachableAccessPred);
3241 for (auto KV : Filtered) {
3242 if (auto *FirstMUD = dyn_cast<MemoryUseOrDef>(KV.first)) {
3243 auto *SecondMUD = dyn_cast<MemoryUseOrDef>(KV.second->getMemoryLeader());
3244 if (FirstMUD && SecondMUD) {
3245 SmallPtrSet<const MemoryAccess *, 8> VisitedMAS;
3246 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3251, __PRETTY_FUNCTION__))
3247 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3251, __PRETTY_FUNCTION__))
3248 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3251, __PRETTY_FUNCTION__))
3249 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3251, __PRETTY_FUNCTION__))
3250 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3251, __PRETTY_FUNCTION__))
3251 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3251, __PRETTY_FUNCTION__))
;
3252 }
3253 } else if (auto *FirstMP = dyn_cast<MemoryPhi>(KV.first)) {
3254 // We can only sanely verify that MemoryDefs in the operand list all have
3255 // the same class.
3256 auto ReachableOperandPred = [&](const Use &U) {
3257 return ReachableEdges.count(
3258 {FirstMP->getIncomingBlock(U), FirstMP->getBlock()}) &&
3259 isa<MemoryDef>(U);
3260
3261 };
3262 // All arguments should in the same class, ignoring unreachable arguments
3263 auto FilteredPhiArgs =
3264 make_filter_range(FirstMP->operands(), ReachableOperandPred);
3265 SmallVector<const CongruenceClass *, 16> PhiOpClasses;
3266 std::transform(FilteredPhiArgs.begin(), FilteredPhiArgs.end(),
3267 std::back_inserter(PhiOpClasses), [&](const Use &U) {
3268 const MemoryDef *MD = cast<MemoryDef>(U);
3269 return ValueToClass.lookup(MD->getMemoryInst());
3270 });
3271 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3272, __PRETTY_FUNCTION__))
3272 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3272, __PRETTY_FUNCTION__))
;
3273 }
3274 }
3275#endif
3276}
3277
3278// Verify that the sparse propagation we did actually found the maximal fixpoint
3279// We do this by storing the value to class mapping, touching all instructions,
3280// and redoing the iteration to see if anything changed.
3281void NewGVN::verifyIterationSettled(Function &F) {
3282#ifndef NDEBUG
3283 LLVM_DEBUG(dbgs() << "Beginning iteration verification\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Beginning iteration verification\n"
; } } while (false)
;
3284 if (DebugCounter::isCounterSet(VNCounter))
3285 DebugCounter::setCounterValue(VNCounter, StartingVNCounter);
3286
3287 // Note that we have to store the actual classes, as we may change existing
3288 // classes during iteration. This is because our memory iteration propagation
3289 // is not perfect, and so may waste a little work. But it should generate
3290 // exactly the same congruence classes we have now, with different IDs.
3291 std::map<const Value *, CongruenceClass> BeforeIteration;
3292
3293 for (auto &KV : ValueToClass) {
3294 if (auto *I = dyn_cast<Instruction>(KV.first))
3295 // Skip unused/dead instructions.
3296 if (InstrToDFSNum(I) == 0)
3297 continue;
3298 BeforeIteration.insert({KV.first, *KV.second});
3299 }
3300
3301 TouchedInstructions.set();
3302 TouchedInstructions.reset(0);
3303 iterateTouchedInstructions();
3304 DenseSet<std::pair<const CongruenceClass *, const CongruenceClass *>>
3305 EqualClasses;
3306 for (const auto &KV : ValueToClass) {
3307 if (auto *I = dyn_cast<Instruction>(KV.first))
3308 // Skip unused/dead instructions.
3309 if (InstrToDFSNum(I) == 0)
3310 continue;
3311 // We could sink these uses, but i think this adds a bit of clarity here as
3312 // to what we are comparing.
3313 auto *BeforeCC = &BeforeIteration.find(KV.first)->second;
3314 auto *AfterCC = KV.second;
3315 // Note that the classes can't change at this point, so we memoize the set
3316 // that are equal.
3317 if (!EqualClasses.count({BeforeCC, AfterCC})) {
3318 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3319, __PRETTY_FUNCTION__))
3319 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3319, __PRETTY_FUNCTION__))
;
3320 EqualClasses.insert({BeforeCC, AfterCC});
3321 }
3322 }
3323#endif
3324}
3325
3326// Verify that for each store expression in the expression to class mapping,
3327// only the latest appears, and multiple ones do not appear.
3328// Because loads do not use the stored value when doing equality with stores,
3329// if we don't erase the old store expressions from the table, a load can find
3330// a no-longer valid StoreExpression.
3331void NewGVN::verifyStoreExpressions() const {
3332#ifndef NDEBUG
3333 // This is the only use of this, and it's not worth defining a complicated
3334 // densemapinfo hash/equality function for it.
3335 std::set<
3336 std::pair<const Value *,
3337 std::tuple<const Value *, const CongruenceClass *, Value *>>>
3338 StoreExpressionSet;
3339 for (const auto &KV : ExpressionToClass) {
3340 if (auto *SE = dyn_cast<StoreExpression>(KV.first)) {
3341 // Make sure a version that will conflict with loads is not already there
3342 auto Res = StoreExpressionSet.insert(
3343 {SE->getOperand(0), std::make_tuple(SE->getMemoryLeader(), KV.second,
3344 SE->getStoredValue())});
3345 bool Okay = Res.second;
3346 // It's okay to have the same expression already in there if it is
3347 // identical in nature.
3348 // This can happen when the leader of the stored value changes over time.
3349 if (!Okay)
3350 Okay = (std::get<1>(Res.first->second) == KV.second) &&
3351 (lookupOperandLeader(std::get<2>(Res.first->second)) ==
3352 lookupOperandLeader(SE->getStoredValue()));
3353 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3353, __PRETTY_FUNCTION__))
;
3354 auto *ValueExpr = ValueToExpression.lookup(SE->getStoreInst());
3355 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3357, __PRETTY_FUNCTION__))
3356 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3357, __PRETTY_FUNCTION__))
3357 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3357, __PRETTY_FUNCTION__))
;
3358 }
3359 }
3360#endif
3361}
3362
3363// This is the main value numbering loop, it iterates over the initial touched
3364// instruction set, propagating value numbers, marking things touched, etc,
3365// until the set of touched instructions is completely empty.
3366void NewGVN::iterateTouchedInstructions() {
3367 unsigned int Iterations = 0;
3368 // Figure out where touchedinstructions starts
3369 int FirstInstr = TouchedInstructions.find_first();
3370 // Nothing set, nothing to iterate, just return.
3371 if (FirstInstr == -1)
3372 return;
3373 const BasicBlock *LastBlock = getBlockForValue(InstrFromDFSNum(FirstInstr));
3374 while (TouchedInstructions.any()) {
3375 ++Iterations;
3376 // Walk through all the instructions in all the blocks in RPO.
3377 // TODO: As we hit a new block, we should push and pop equalities into a
3378 // table lookupOperandLeader can use, to catch things PredicateInfo
3379 // might miss, like edge-only equivalences.
3380 for (unsigned InstrNum : TouchedInstructions.set_bits()) {
3381
3382 // This instruction was found to be dead. We don't bother looking
3383 // at it again.
3384 if (InstrNum == 0) {
3385 TouchedInstructions.reset(InstrNum);
3386 continue;
3387 }
3388
3389 Value *V = InstrFromDFSNum(InstrNum);
3390 const BasicBlock *CurrBlock = getBlockForValue(V);
3391
3392 // If we hit a new block, do reachability processing.
3393 if (CurrBlock != LastBlock) {
3394 LastBlock = CurrBlock;
3395 bool BlockReachable = ReachableBlocks.count(CurrBlock);
3396 const auto &CurrInstRange = BlockInstRange.lookup(CurrBlock);
3397
3398 // If it's not reachable, erase any touched instructions and move on.
3399 if (!BlockReachable) {
3400 TouchedInstructions.reset(CurrInstRange.first, CurrInstRange.second);
3401 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)
3402 << getBlockName(CurrBlock)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Skipping instructions in block "
<< getBlockName(CurrBlock) << " because it is unreachable\n"
; } } while (false)
3403 << " 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)
;
3404 continue;
3405 }
3406 updateProcessedCount(CurrBlock);
3407 }
3408 // Reset after processing (because we may mark ourselves as touched when
3409 // we propagate equalities).
3410 TouchedInstructions.reset(InstrNum);
3411
3412 if (auto *MP = dyn_cast<MemoryPhi>(V)) {
3413 LLVM_DEBUG(dbgs() << "Processing MemoryPhi " << *MP << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Processing MemoryPhi " <<
*MP << "\n"; } } while (false)
;
3414 valueNumberMemoryPhi(MP);
3415 } else if (auto *I = dyn_cast<Instruction>(V)) {
3416 valueNumberInstruction(I);
3417 } else {
3418 llvm_unreachable("Should have been a MemoryPhi or Instruction")::llvm::llvm_unreachable_internal("Should have been a MemoryPhi or Instruction"
, "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3418)
;
3419 }
3420 updateProcessedCount(V);
3421 }
3422 }
3423 NumGVNMaxIterations = std::max(NumGVNMaxIterations.getValue(), Iterations);
3424}
3425
3426// This is the main transformation entry point.
3427bool NewGVN::runGVN() {
3428 if (DebugCounter::isCounterSet(VNCounter))
3429 StartingVNCounter = DebugCounter::getCounterValue(VNCounter);
3430 bool Changed = false;
3431 NumFuncArgs = F.arg_size();
3432 MSSAWalker = MSSA->getWalker();
3433 SingletonDeadExpression = new (ExpressionAllocator) DeadExpression();
3434
3435 // Count number of instructions for sizing of hash tables, and come
3436 // up with a global dfs numbering for instructions.
3437 unsigned ICount = 1;
3438 // Add an empty instruction to account for the fact that we start at 1
3439 DFSToInstr.emplace_back(nullptr);
3440 // Note: We want ideal RPO traversal of the blocks, which is not quite the
3441 // same as dominator tree order, particularly with regard whether backedges
3442 // get visited first or second, given a block with multiple successors.
3443 // If we visit in the wrong order, we will end up performing N times as many
3444 // iterations.
3445 // The dominator tree does guarantee that, for a given dom tree node, it's
3446 // parent must occur before it in the RPO ordering. Thus, we only need to sort
3447 // the siblings.
3448 ReversePostOrderTraversal<Function *> RPOT(&F);
3449 unsigned Counter = 0;
3450 for (auto &B : RPOT) {
3451 auto *Node = DT->getNode(B);
3452 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3452, __PRETTY_FUNCTION__))
;
3453 RPOOrdering[Node] = ++Counter;
3454 }
3455 // Sort dominator tree children arrays into RPO.
3456 for (auto &B : RPOT) {
3457 auto *Node = DT->getNode(B);
3458 if (Node->getChildren().size() > 1)
3459 llvm::sort(Node->begin(), Node->end(),
3460 [&](const DomTreeNode *A, const DomTreeNode *B) {
3461 return RPOOrdering[A] < RPOOrdering[B];
3462 });
3463 }
3464
3465 // Now a standard depth first ordering of the domtree is equivalent to RPO.
3466 for (auto DTN : depth_first(DT->getRootNode())) {
3467 BasicBlock *B = DTN->getBlock();
3468 const auto &BlockRange = assignDFSNumbers(B, ICount);
3469 BlockInstRange.insert({B, BlockRange});
3470 ICount += BlockRange.second - BlockRange.first;
3471 }
3472 initializeCongruenceClasses(F);
3473
3474 TouchedInstructions.resize(ICount);
3475 // Ensure we don't end up resizing the expressionToClass map, as
3476 // that can be quite expensive. At most, we have one expression per
3477 // instruction.
3478 ExpressionToClass.reserve(ICount);
3479
3480 // Initialize the touched instructions to include the entry block.
3481 const auto &InstRange = BlockInstRange.lookup(&F.getEntryBlock());
3482 TouchedInstructions.set(InstRange.first, InstRange.second);
3483 LLVM_DEBUG(dbgs() << "Block " << getBlockName(&F.getEntryBlock())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
&F.getEntryBlock()) << " marked reachable\n"; } } while
(false)
3484 << " marked reachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Block " << getBlockName(
&F.getEntryBlock()) << " marked reachable\n"; } } while
(false)
;
3485 ReachableBlocks.insert(&F.getEntryBlock());
3486
3487 iterateTouchedInstructions();
3488 verifyMemoryCongruency();
3489 verifyIterationSettled(F);
3490 verifyStoreExpressions();
3491
3492 Changed |= eliminateInstructions(F);
3493
3494 // Delete all instructions marked for deletion.
3495 for (Instruction *ToErase : InstructionsToErase) {
3496 if (!ToErase->use_empty())
3497 ToErase->replaceAllUsesWith(UndefValue::get(ToErase->getType()));
3498
3499 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3500, __PRETTY_FUNCTION__))
3500 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3500, __PRETTY_FUNCTION__))
;
3501 ToErase->eraseFromParent();
3502 }
3503 Changed |= !InstructionsToErase.empty();
3504
3505 // Delete all unreachable blocks.
3506 auto UnreachableBlockPred = [&](const BasicBlock &BB) {
3507 return !ReachableBlocks.count(&BB);
3508 };
3509
3510 for (auto &BB : make_filter_range(F, UnreachableBlockPred)) {
3511 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)
3512 << " is unreachable\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "We believe block " << getBlockName
(&BB) << " is unreachable\n"; } } while (false)
;
3513 deleteInstructionsInBlock(&BB);
3514 Changed = true;
3515 }
3516
3517 cleanupTables();
3518 return Changed;
3519}
3520
3521struct NewGVN::ValueDFS {
3522 int DFSIn = 0;
3523 int DFSOut = 0;
3524 int LocalNum = 0;
3525
3526 // Only one of Def and U will be set.
3527 // The bool in the Def tells us whether the Def is the stored value of a
3528 // store.
3529 PointerIntPair<Value *, 1, bool> Def;
3530 Use *U = nullptr;
3531
3532 bool operator<(const ValueDFS &Other) const {
3533 // It's not enough that any given field be less than - we have sets
3534 // of fields that need to be evaluated together to give a proper ordering.
3535 // For example, if you have;
3536 // DFS (1, 3)
3537 // Val 0
3538 // DFS (1, 2)
3539 // Val 50
3540 // We want the second to be less than the first, but if we just go field
3541 // by field, we will get to Val 0 < Val 50 and say the first is less than
3542 // the second. We only want it to be less than if the DFS orders are equal.
3543 //
3544 // Each LLVM instruction only produces one value, and thus the lowest-level
3545 // differentiator that really matters for the stack (and what we use as as a
3546 // replacement) is the local dfs number.
3547 // Everything else in the structure is instruction level, and only affects
3548 // the order in which we will replace operands of a given instruction.
3549 //
3550 // For a given instruction (IE things with equal dfsin, dfsout, localnum),
3551 // the order of replacement of uses does not matter.
3552 // IE given,
3553 // a = 5
3554 // b = a + a
3555 // When you hit b, you will have two valuedfs with the same dfsin, out, and
3556 // localnum.
3557 // The .val will be the same as well.
3558 // The .u's will be different.
3559 // You will replace both, and it does not matter what order you replace them
3560 // in (IE whether you replace operand 2, then operand 1, or operand 1, then
3561 // operand 2).
3562 // Similarly for the case of same dfsin, dfsout, localnum, but different
3563 // .val's
3564 // a = 5
3565 // b = 6
3566 // c = a + b
3567 // in c, we will a valuedfs for a, and one for b,with everything the same
3568 // but .val and .u.
3569 // It does not matter what order we replace these operands in.
3570 // You will always end up with the same IR, and this is guaranteed.
3571 return std::tie(DFSIn, DFSOut, LocalNum, Def, U) <
3572 std::tie(Other.DFSIn, Other.DFSOut, Other.LocalNum, Other.Def,
3573 Other.U);
3574 }
3575};
3576
3577// This function converts the set of members for a congruence class from values,
3578// to sets of defs and uses with associated DFS info. The total number of
3579// reachable uses for each value is stored in UseCount, and instructions that
3580// seem
3581// dead (have no non-dead uses) are stored in ProbablyDead.
3582void NewGVN::convertClassToDFSOrdered(
3583 const CongruenceClass &Dense, SmallVectorImpl<ValueDFS> &DFSOrderedSet,
3584 DenseMap<const Value *, unsigned int> &UseCounts,
3585 SmallPtrSetImpl<Instruction *> &ProbablyDead) const {
3586 for (auto D : Dense) {
3587 // First add the value.
3588 BasicBlock *BB = getBlockForValue(D);
3589 // Constants are handled prior to ever calling this function, so
3590 // we should only be left with instructions as members.
3591 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3591, __PRETTY_FUNCTION__))
;
3592 ValueDFS VDDef;
3593 DomTreeNode *DomNode = DT->getNode(BB);
3594 VDDef.DFSIn = DomNode->getDFSNumIn();
3595 VDDef.DFSOut = DomNode->getDFSNumOut();
3596 // If it's a store, use the leader of the value operand, if it's always
3597 // available, or the value operand. TODO: We could do dominance checks to
3598 // find a dominating leader, but not worth it ATM.
3599 if (auto *SI = dyn_cast<StoreInst>(D)) {
3600 auto Leader = lookupOperandLeader(SI->getValueOperand());
3601 if (alwaysAvailable(Leader)) {
3602 VDDef.Def.setPointer(Leader);
3603 } else {
3604 VDDef.Def.setPointer(SI->getValueOperand());
3605 VDDef.Def.setInt(true);
3606 }
3607 } else {
3608 VDDef.Def.setPointer(D);
3609 }
3610 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3611, __PRETTY_FUNCTION__))
3611 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3611, __PRETTY_FUNCTION__))
;
3612 Instruction *Def = cast<Instruction>(D);
3613 VDDef.LocalNum = InstrToDFSNum(D);
3614 DFSOrderedSet.push_back(VDDef);
3615 // If there is a phi node equivalent, add it
3616 if (auto *PN = RealToTemp.lookup(Def)) {
3617 auto *PHIE =
3618 dyn_cast_or_null<PHIExpression>(ValueToExpression.lookup(Def));
3619 if (PHIE) {
3620 VDDef.Def.setInt(false);
3621 VDDef.Def.setPointer(PN);
3622 VDDef.LocalNum = 0;
3623 DFSOrderedSet.push_back(VDDef);
3624 }
3625 }
3626
3627 unsigned int UseCount = 0;
3628 // Now add the uses.
3629 for (auto &U : Def->uses()) {
3630 if (auto *I = dyn_cast<Instruction>(U.getUser())) {
3631 // Don't try to replace into dead uses
3632 if (InstructionsToErase.count(I))
3633 continue;
3634 ValueDFS VDUse;
3635 // Put the phi node uses in the incoming block.
3636 BasicBlock *IBlock;
3637 if (auto *P = dyn_cast<PHINode>(I)) {
3638 IBlock = P->getIncomingBlock(U);
3639 // Make phi node users appear last in the incoming block
3640 // they are from.
3641 VDUse.LocalNum = InstrDFS.size() + 1;
3642 } else {
3643 IBlock = getBlockForValue(I);
3644 VDUse.LocalNum = InstrToDFSNum(I);
3645 }
3646
3647 // Skip uses in unreachable blocks, as we're going
3648 // to delete them.
3649 if (ReachableBlocks.count(IBlock) == 0)
3650 continue;
3651
3652 DomTreeNode *DomNode = DT->getNode(IBlock);
3653 VDUse.DFSIn = DomNode->getDFSNumIn();
3654 VDUse.DFSOut = DomNode->getDFSNumOut();
3655 VDUse.U = &U;
3656 ++UseCount;
3657 DFSOrderedSet.emplace_back(VDUse);
3658 }
3659 }
3660
3661 // If there are no uses, it's probably dead (but it may have side-effects,
3662 // so not definitely dead. Otherwise, store the number of uses so we can
3663 // track if it becomes dead later).
3664 if (UseCount == 0)
3665 ProbablyDead.insert(Def);
3666 else
3667 UseCounts[Def] = UseCount;
3668 }
3669}
3670
3671// This function converts the set of members for a congruence class from values,
3672// to the set of defs for loads and stores, with associated DFS info.
3673void NewGVN::convertClassToLoadsAndStores(
3674 const CongruenceClass &Dense,
3675 SmallVectorImpl<ValueDFS> &LoadsAndStores) const {
3676 for (auto D : Dense) {
3677 if (!isa<LoadInst>(D) && !isa<StoreInst>(D))
3678 continue;
3679
3680 BasicBlock *BB = getBlockForValue(D);
3681 ValueDFS VD;
3682 DomTreeNode *DomNode = DT->getNode(BB);
3683 VD.DFSIn = DomNode->getDFSNumIn();
3684 VD.DFSOut = DomNode->getDFSNumOut();
3685 VD.Def.setPointer(D);
3686
3687 // If it's an instruction, use the real local dfs number.
3688 if (auto *I = dyn_cast<Instruction>(D))
3689 VD.LocalNum = InstrToDFSNum(I);
3690 else
3691 llvm_unreachable("Should have been an instruction")::llvm::llvm_unreachable_internal("Should have been an instruction"
, "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3691)
;
3692
3693 LoadsAndStores.emplace_back(VD);
3694 }
3695}
3696
3697static void patchAndReplaceAllUsesWith(Instruction *I, Value *Repl) {
3698 patchReplacementInstruction(I, Repl);
3699 I->replaceAllUsesWith(Repl);
3700}
3701
3702void NewGVN::deleteInstructionsInBlock(BasicBlock *BB) {
3703 LLVM_DEBUG(dbgs() << " BasicBlock Dead:" << *BB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << " BasicBlock Dead:" << *
BB; } } while (false)
;
3704 ++NumGVNBlocksDeleted;
3705
3706 // Delete the instructions backwards, as it has a reduced likelihood of having
3707 // to update as many def-use and use-def chains. Start after the terminator.
3708 auto StartPoint = BB->rbegin();
3709 ++StartPoint;
3710 // Note that we explicitly recalculate BB->rend() on each iteration,
3711 // as it may change when we remove the first instruction.
3712 for (BasicBlock::reverse_iterator I(StartPoint); I != BB->rend();) {
3713 Instruction &Inst = *I++;
3714 if (!Inst.use_empty())
3715 Inst.replaceAllUsesWith(UndefValue::get(Inst.getType()));
3716 if (isa<LandingPadInst>(Inst))
3717 continue;
3718
3719 Inst.eraseFromParent();
3720 ++NumGVNInstrDeleted;
3721 }
3722 // Now insert something that simplifycfg will turn into an unreachable.
3723 Type *Int8Ty = Type::getInt8Ty(BB->getContext());
3724 new StoreInst(UndefValue::get(Int8Ty),
3725 Constant::getNullValue(Int8Ty->getPointerTo()),
3726 BB->getTerminator());
3727}
3728
3729void NewGVN::markInstructionForDeletion(Instruction *I) {
3730 LLVM_DEBUG(dbgs() << "Marking " << *I << " for deletion\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Marking " << *I <<
" for deletion\n"; } } while (false)
;
3731 InstructionsToErase.insert(I);
3732}
3733
3734void NewGVN::replaceInstruction(Instruction *I, Value *V) {
3735 LLVM_DEBUG(dbgs() << "Replacing " << *I << " with " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Replacing " << *I <<
" with " << *V << "\n"; } } while (false)
;
3736 patchAndReplaceAllUsesWith(I, V);
3737 // We save the actual erasing to avoid invalidating memory
3738 // dependencies until we are done with everything.
3739 markInstructionForDeletion(I);
3740}
3741
3742namespace {
3743
3744// This is a stack that contains both the value and dfs info of where
3745// that value is valid.
3746class ValueDFSStack {
3747public:
3748 Value *back() const { return ValueStack.back(); }
3749 std::pair<int, int> dfs_back() const { return DFSStack.back(); }
3750
3751 void push_back(Value *V, int DFSIn, int DFSOut) {
3752 ValueStack.emplace_back(V);
3753 DFSStack.emplace_back(DFSIn, DFSOut);
3754 }
3755
3756 bool empty() const { return DFSStack.empty(); }
3757
3758 bool isInScope(int DFSIn, int DFSOut) const {
3759 if (empty())
3760 return false;
3761 return DFSIn >= DFSStack.back().first && DFSOut <= DFSStack.back().second;
3762 }
3763
3764 void popUntilDFSScope(int DFSIn, int DFSOut) {
3765
3766 // These two should always be in sync at this point.
3767 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3768, __PRETTY_FUNCTION__))
3768 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3768, __PRETTY_FUNCTION__))
;
3769 while (
3770 !DFSStack.empty() &&
3771 !(DFSIn >= DFSStack.back().first && DFSOut <= DFSStack.back().second)) {
3772 DFSStack.pop_back();
3773 ValueStack.pop_back();
3774 }
3775 }
3776
3777private:
3778 SmallVector<Value *, 8> ValueStack;
3779 SmallVector<std::pair<int, int>, 8> DFSStack;
3780};
3781
3782} // end anonymous namespace
3783
3784// Given an expression, get the congruence class for it.
3785CongruenceClass *NewGVN::getClassForExpression(const Expression *E) const {
3786 if (auto *VE = dyn_cast<VariableExpression>(E))
3787 return ValueToClass.lookup(VE->getVariableValue());
3788 else if (isa<DeadExpression>(E))
3789 return TOPClass;
3790 return ExpressionToClass.lookup(E);
3791}
3792
3793// Given a value and a basic block we are trying to see if it is available in,
3794// see if the value has a leader available in that block.
3795Value *NewGVN::findPHIOfOpsLeader(const Expression *E,
3796 const Instruction *OrigInst,
3797 const BasicBlock *BB) const {
3798 // It would already be constant if we could make it constant
3799 if (auto *CE = dyn_cast<ConstantExpression>(E))
3800 return CE->getConstantValue();
3801 if (auto *VE = dyn_cast<VariableExpression>(E)) {
3802 auto *V = VE->getVariableValue();
3803 if (alwaysAvailable(V) || DT->dominates(getBlockForValue(V), BB))
3804 return VE->getVariableValue();
3805 }
3806
3807 auto *CC = getClassForExpression(E);
3808 if (!CC)
3809 return nullptr;
3810 if (alwaysAvailable(CC->getLeader()))
3811 return CC->getLeader();
3812
3813 for (auto Member : *CC) {
3814 auto *MemberInst = dyn_cast<Instruction>(Member);
3815 if (MemberInst == OrigInst)
3816 continue;
3817 // Anything that isn't an instruction is always available.
3818 if (!MemberInst)
3819 return Member;
3820 if (DT->dominates(getBlockForValue(MemberInst), BB))
3821 return Member;
3822 }
3823 return nullptr;
3824}
3825
3826bool NewGVN::eliminateInstructions(Function &F) {
3827 // This is a non-standard eliminator. The normal way to eliminate is
3828 // to walk the dominator tree in order, keeping track of available
3829 // values, and eliminating them. However, this is mildly
3830 // pointless. It requires doing lookups on every instruction,
3831 // regardless of whether we will ever eliminate it. For
3832 // instructions part of most singleton congruence classes, we know we
3833 // will never eliminate them.
3834
3835 // Instead, this eliminator looks at the congruence classes directly, sorts
3836 // them into a DFS ordering of the dominator tree, and then we just
3837 // perform elimination straight on the sets by walking the congruence
3838 // class member uses in order, and eliminate the ones dominated by the
3839 // last member. This is worst case O(E log E) where E = number of
3840 // instructions in a single congruence class. In theory, this is all
3841 // instructions. In practice, it is much faster, as most instructions are
3842 // either in singleton congruence classes or can't possibly be eliminated
3843 // anyway (if there are no overlapping DFS ranges in class).
3844 // When we find something not dominated, it becomes the new leader
3845 // for elimination purposes.
3846 // TODO: If we wanted to be faster, We could remove any members with no
3847 // overlapping ranges while sorting, as we will never eliminate anything
3848 // with those members, as they don't dominate anything else in our set.
3849
3850 bool AnythingReplaced = false;
3851
3852 // Since we are going to walk the domtree anyway, and we can't guarantee the
3853 // DFS numbers are updated, we compute some ourselves.
3854 DT->updateDFSNumbers();
3855
3856 // Go through all of our phi nodes, and kill the arguments associated with
3857 // unreachable edges.
3858 auto ReplaceUnreachablePHIArgs = [&](PHINode *PHI, BasicBlock *BB) {
3859 for (auto &Operand : PHI->incoming_values())
3860 if (!ReachableEdges.count({PHI->getIncomingBlock(Operand), BB})) {
3861 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)
3862 << " 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)
3863 << 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)
3864 << " 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)
;
3865 Operand.set(UndefValue::get(PHI->getType()));
3866 }
3867 };
3868 // Replace unreachable phi arguments.
3869 // At this point, RevisitOnReachabilityChange only contains:
3870 //
3871 // 1. PHIs
3872 // 2. Temporaries that will convert to PHIs
3873 // 3. Operations that are affected by an unreachable edge but do not fit into
3874 // 1 or 2 (rare).
3875 // So it is a slight overshoot of what we want. We could make it exact by
3876 // using two SparseBitVectors per block.
3877 DenseMap<const BasicBlock *, unsigned> ReachablePredCount;
3878 for (auto &KV : ReachableEdges)
3879 ReachablePredCount[KV.getEnd()]++;
3880 for (auto &BBPair : RevisitOnReachabilityChange) {
3881 for (auto InstNum : BBPair.second) {
3882 auto *Inst = InstrFromDFSNum(InstNum);
3883 auto *PHI = dyn_cast<PHINode>(Inst);
3884 PHI = PHI ? PHI : dyn_cast_or_null<PHINode>(RealToTemp.lookup(Inst));
3885 if (!PHI)
3886 continue;
3887 auto *BB = BBPair.first;
3888 if (ReachablePredCount.lookup(BB) != PHI->getNumIncomingValues())
3889 ReplaceUnreachablePHIArgs(PHI, BB);
3890 }
3891 }
3892
3893 // Map to store the use counts
3894 DenseMap<const Value *, unsigned int> UseCounts;
3895 for (auto *CC : reverse(CongruenceClasses)) {
3896 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)
3897 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Eliminating in congruence class "
<< CC->getID() << "\n"; } } while (false)
;
3898 // Track the equivalent store info so we can decide whether to try
3899 // dead store elimination.
3900 SmallVector<ValueDFS, 8> PossibleDeadStores;
3901 SmallPtrSet<Instruction *, 8> ProbablyDead;
3902 if (CC->isDead() || CC->empty())
3903 continue;
3904 // Everything still in the TOP class is unreachable or dead.
3905 if (CC == TOPClass) {
3906 for (auto M : *CC) {
3907 auto *VTE = ValueToExpression.lookup(M);
3908 if (VTE && isa<DeadExpression>(VTE))
3909 markInstructionForDeletion(cast<Instruction>(M));
3910 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3913, __PRETTY_FUNCTION__))
3911 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3913, __PRETTY_FUNCTION__))
3912 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3913, __PRETTY_FUNCTION__))
3913 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3913, __PRETTY_FUNCTION__))
;
3914 }
3915 continue;
3916 }
3917
3918 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3918, __PRETTY_FUNCTION__))
;
3919 // If this is a leader that is always available, and it's a
3920 // constant or has no equivalences, just replace everything with
3921 // it. We then update the congruence class with whatever members
3922 // are left.
3923 Value *Leader =
3924 CC->getStoredValue() ? CC->getStoredValue() : CC->getLeader();
3925 if (alwaysAvailable(Leader)) {
3926 CongruenceClass::MemberSet MembersLeft;
3927 for (auto M : *CC) {
3928 Value *Member = M;
3929 // Void things have no uses we can replace.
3930 if (Member == Leader || !isa<Instruction>(Member) ||
3931 Member->getType()->isVoidTy()) {
3932 MembersLeft.insert(Member);
3933 continue;
3934 }
3935 LLVM_DEBUG(dbgs() << "Found replacement " << *(Leader) << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
(Leader) << " for " << *Member << "\n"; } }
while (false)
3936 << *Member << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
(Leader) << " for " << *Member << "\n"; } }
while (false)
;
3937 auto *I = cast<Instruction>(Member);
3938 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 3938, __PRETTY_FUNCTION__))
;
3939 replaceInstruction(I, Leader);
3940 AnythingReplaced = true;
3941 }
3942 CC->swap(MembersLeft);
3943 } else {
3944 // If this is a singleton, we can skip it.
3945 if (CC->size() != 1 || RealToTemp.count(Leader)) {
3946 // This is a stack because equality replacement/etc may place
3947 // constants in the middle of the member list, and we want to use
3948 // those constant values in preference to the current leader, over
3949 // the scope of those constants.
3950 ValueDFSStack EliminationStack;
3951
3952 // Convert the members to DFS ordered sets and then merge them.
3953 SmallVector<ValueDFS, 8> DFSOrderedSet;
3954 convertClassToDFSOrdered(*CC, DFSOrderedSet, UseCounts, ProbablyDead);
3955
3956 // Sort the whole thing.
3957 llvm::sort(DFSOrderedSet);
3958 for (auto &VD : DFSOrderedSet) {
3959 int MemberDFSIn = VD.DFSIn;
3960 int MemberDFSOut = VD.DFSOut;
3961 Value *Def = VD.Def.getPointer();
3962 bool FromStore = VD.Def.getInt();
3963 Use *U = VD.U;
3964 // We ignore void things because we can't get a value from them.
3965 if (Def && Def->getType()->isVoidTy())
3966 continue;
3967 auto *DefInst = dyn_cast_or_null<Instruction>(Def);
3968 if (DefInst && AllTempInstructions.count(DefInst)) {
3969 auto *PN = cast<PHINode>(DefInst);
3970
3971 // If this is a value phi and that's the expression we used, insert
3972 // it into the program
3973 // remove from temp instruction list.
3974 AllTempInstructions.erase(PN);
3975 auto *DefBlock = getBlockForValue(Def);
3976 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)
3977 << " 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)
3978 << 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)
;
3979 PN->insertBefore(&DefBlock->front());
3980 Def = PN;
3981 NumGVNPHIOfOpsEliminations++;
3982 }
3983
3984 if (EliminationStack.empty()) {
3985 LLVM_DEBUG(dbgs() << "Elimination Stack is empty\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Elimination Stack is empty\n";
} } while (false)
;
3986 } else {
3987 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)
3988 << 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)
3989 << 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)
;
3990 }
3991
3992 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)
3993 << MemberDFSOut << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Current DFS numbers are (" <<
MemberDFSIn << "," << MemberDFSOut << ")\n"
; } } while (false)
;
3994 // First, we see if we are out of scope or empty. If so,
3995 // and there equivalences, we try to replace the top of
3996 // stack with equivalences (if it's on the stack, it must
3997 // not have been eliminated yet).
3998 // Then we synchronize to our current scope, by
3999 // popping until we are back within a DFS scope that
4000 // dominates the current member.
4001 // Then, what happens depends on a few factors
4002 // If the stack is now empty, we need to push
4003 // If we have a constant or a local equivalence we want to
4004 // start using, we also push.
4005 // Otherwise, we walk along, processing members who are
4006 // dominated by this scope, and eliminate them.
4007 bool ShouldPush = Def && EliminationStack.empty();
4008 bool OutOfScope =
4009 !EliminationStack.isInScope(MemberDFSIn, MemberDFSOut);
4010
4011 if (OutOfScope || ShouldPush) {
4012 // Sync to our current scope.
4013 EliminationStack.popUntilDFSScope(MemberDFSIn, MemberDFSOut);
4014 bool ShouldPush = Def && EliminationStack.empty();
4015 if (ShouldPush) {
4016 EliminationStack.push_back(Def, MemberDFSIn, MemberDFSOut);
4017 }
4018 }
4019
4020 // Skip the Def's, we only want to eliminate on their uses. But mark
4021 // dominated defs as dead.
4022 if (Def) {
4023 // For anything in this case, what and how we value number
4024 // guarantees that any side-effets that would have occurred (ie
4025 // throwing, etc) can be proven to either still occur (because it's
4026 // dominated by something that has the same side-effects), or never
4027 // occur. Otherwise, we would not have been able to prove it value
4028 // equivalent to something else. For these things, we can just mark
4029 // it all dead. Note that this is different from the "ProbablyDead"
4030 // set, which may not be dominated by anything, and thus, are only
4031 // easy to prove dead if they are also side-effect free. Note that
4032 // because stores are put in terms of the stored value, we skip
4033 // stored values here. If the stored value is really dead, it will
4034 // still be marked for deletion when we process it in its own class.
4035 if (!EliminationStack.empty() && Def != EliminationStack.back() &&
4036 isa<Instruction>(Def) && !FromStore)
4037 markInstructionForDeletion(cast<Instruction>(Def));
4038 continue;
4039 }
4040 // At this point, we know it is a Use we are trying to possibly
4041 // replace.
4042
4043 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 4044, __PRETTY_FUNCTION__))
4044 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 4044, __PRETTY_FUNCTION__))
;
4045 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 4046, __PRETTY_FUNCTION__))
4046 "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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 4046, __PRETTY_FUNCTION__))
;
4047
4048 // If the thing we are replacing into is already marked to be dead,
4049 // this use is dead. Note that this is true regardless of whether
4050 // we have anything dominating the use or not. We do this here
4051 // because we are already walking all the uses anyway.
4052 Instruction *InstUse = cast<Instruction>(U->getUser());
4053 if (InstructionsToErase.count(InstUse)) {
4054 auto &UseCount = UseCounts[U->get()];
4055 if (--UseCount == 0) {
4056 ProbablyDead.insert(cast<Instruction>(U->get()));
4057 }
4058 }
4059
4060 // If we get to this point, and the stack is empty we must have a use
4061 // with nothing we can use to eliminate this use, so just skip it.
4062 if (EliminationStack.empty())
4063 continue;
4064
4065 Value *DominatingLeader = EliminationStack.back();
4066
4067 auto *II = dyn_cast<IntrinsicInst>(DominatingLeader);
4068 bool isSSACopy = II && II->getIntrinsicID() == Intrinsic::ssa_copy;
4069 if (isSSACopy)
4070 DominatingLeader = II->getOperand(0);
4071
4072 // Don't replace our existing users with ourselves.
4073 if (U->get() == DominatingLeader)
4074 continue;
4075 LLVM_DEBUG(dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
DominatingLeader << " for " << *U->get() <<
" in " << *(U->getUser()) << "\n"; } } while (
false)
4076 << "Found replacement " << *DominatingLeader << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("newgvn")) { dbgs() << "Found replacement " << *
DominatingLeader << " for " << *U->get() <<
" in " << *(U->getUser()) << "\n"; } } while (
false)
4077 << *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)
;
4078
4079 // If we replaced something in an instruction, handle the patching of
4080 // metadata. Skip this if we are replacing predicateinfo with its
4081 // original operand, as we already know we can just drop it.
4082 auto *ReplacedInst = cast<Instruction>(U->get());
4083 auto *PI = PredInfo->getPredicateInfoFor(ReplacedInst);
4084 if (!PI || DominatingLeader != PI->OriginalOp)
4085 patchReplacementInstruction(ReplacedInst, DominatingLeader);
4086 U->set(DominatingLeader);
4087 // This is now a use of the dominating leader, which means if the
4088 // dominating leader was dead, it's now live!
4089 auto &LeaderUseCount = UseCounts[DominatingLeader];
4090 // It's about to be alive again.
4091 if (LeaderUseCount == 0 && isa<Instruction>(DominatingLeader))
4092 ProbablyDead.erase(cast<Instruction>(DominatingLeader));
4093 // Copy instructions, however, are still dead because we use their
4094 // operand as the leader.
4095 if (LeaderUseCount == 0 && isSSACopy)
4096 ProbablyDead.insert(II);
4097 ++LeaderUseCount;
4098 AnythingReplaced = true;
4099 }
4100 }
4101 }
4102
4103 // At this point, anything still in the ProbablyDead set is actually dead if
4104 // would be trivially dead.
4105 for (auto *I : ProbablyDead)
4106 if (wouldInstructionBeTriviallyDead(I))
4107 markInstructionForDeletion(I);
4108
4109 // Cleanup the congruence class.
4110 CongruenceClass::MemberSet MembersLeft;
4111 for (auto *Member : *CC)
4112 if (!isa<Instruction>(Member) ||
4113 !InstructionsToErase.count(cast<Instruction>(Member)))
4114 MembersLeft.insert(Member);
4115 CC->swap(MembersLeft);
4116
4117 // If we have possible dead stores to look at, try to eliminate them.
4118 if (CC->getStoreCount() > 0) {
4119 convertClassToLoadsAndStores(*CC, PossibleDeadStores);
4120 llvm::sort(PossibleDeadStores);
4121 ValueDFSStack EliminationStack;
4122 for (auto &VD : PossibleDeadStores) {
4123 int MemberDFSIn = VD.DFSIn;
4124 int MemberDFSOut = VD.DFSOut;
4125 Instruction *Member = cast<Instruction>(VD.Def.getPointer());
4126 if (EliminationStack.empty() ||
4127 !EliminationStack.isInScope(MemberDFSIn, MemberDFSOut)) {
4128 // Sync to our current scope.
4129 EliminationStack.popUntilDFSScope(MemberDFSIn, MemberDFSOut);
4130 if (EliminationStack.empty()) {
4131 EliminationStack.push_back(Member, MemberDFSIn, MemberDFSOut);
4132 continue;
4133 }
4134 }
4135 // We already did load elimination, so nothing to do here.
4136 if (isa<LoadInst>(Member))
4137 continue;
4138 assert(!EliminationStack.empty())((!EliminationStack.empty()) ? static_cast<void> (0) : __assert_fail
("!EliminationStack.empty()", "/build/llvm-toolchain-snapshot-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 4138, __PRETTY_FUNCTION__))
;
4139 Instruction *Leader = cast<Instruction>(EliminationStack.back());
4140 (void)Leader;
4141 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-8~svn345461/lib/Transforms/Scalar/NewGVN.cpp"
, 4141, __PRETTY_FUNCTION__))
;
4142 // Member is dominater by Leader, and thus dead
4143 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)
4144 << " 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)
;
4145 markInstructionForDeletion(Member);
4146 CC->erase(Member);
4147 ++NumGVNDeadStores;
4148 }
4149 }
4150 }
4151 return AnythingReplaced;
4152}
4153
4154// This function provides global ranking of operations so that we can place them
4155// in a canonical order. Note that rank alone is not necessarily enough for a
4156// complete ordering, as constants all have the same rank. However, generally,
4157// we will simplify an operation with all constants so that it doesn't matter
4158// what order they appear in.
4159unsigned int NewGVN::getRank(const Value *V) const {
4160 // Prefer constants to undef to anything else
4161 // Undef is a constant, have to check it first.
4162 // Prefer smaller constants to constantexprs
4163 if (isa<ConstantExpr>(V))
4164 return 2;
4165 if (isa<UndefValue>(V))
4166 return 1;
4167 if (isa<Constant>(V))
4168 return 0;
4169 else if (auto *A = dyn_cast<Argument>(V))
4170 return 3 + A->getArgNo();
4171
4172 // Need to shift the instruction DFS by number of arguments + 3 to account for
4173 // the constant and argument ranking above.
4174 unsigned Result = InstrToDFSNum(V);
4175 if (Result > 0)
4176 return 4 + NumFuncArgs + Result;
4177 // Unreachable or something else, just return a really large number.
4178 return ~0;
4179}
4180
4181// This is a function that says whether two commutative operations should
4182// have their order swapped when canonicalizing.
4183bool NewGVN::shouldSwapOperands(const Value *A, const Value *B) const {
4184 // Because we only care about a total ordering, and don't rewrite expressions
4185 // in this order, we order by rank, which will give a strict weak ordering to
4186 // everything but constants, and then we order by pointer address.
4187 return std::make_pair(getRank(A), A) > std::make_pair(getRank(B), B);
4188}
4189
4190namespace {
4191
4192class NewGVNLegacyPass : public FunctionPass {
4193public:
4194 // Pass identification, replacement for typeid.
4195 static char ID;
4196
4197 NewGVNLegacyPass() : FunctionPass(ID) {
4198 initializeNewGVNLegacyPassPass(*PassRegistry::getPassRegistry());
4199 }
4200
4201 bool runOnFunction(Function &F) override;
4202
4203private:
4204 void getAnalysisUsage(AnalysisUsage &AU) const override {
4205 AU.addRequired<AssumptionCacheTracker>();
4206 AU.addRequired<DominatorTreeWrapperPass>();
4207 AU.addRequired<TargetLibraryInfoWrapperPass>();
4208 AU.addRequired<MemorySSAWrapperPass>();
4209 AU.addRequired<AAResultsWrapperPass>();
4210 AU.addPreserved<DominatorTreeWrapperPass>();
4211 AU.addPreserved<GlobalsAAWrapperPass>();
4212 }
4213};
4214
4215} // end anonymous namespace
4216
4217bool NewGVNLegacyPass::runOnFunction(Function &F) {
4218 if (skipFunction(F))
4219 return false;
4220 return NewGVN(F, &getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
4221 &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F),
4222 &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(),
4223 &getAnalysis<AAResultsWrapperPass>().getAAResults(),
4224 &getAnalysis<MemorySSAWrapperPass>().getMSSA(),
4225 F.getParent()->getDataLayout())
4226 .runGVN();
4227}
4228
4229char NewGVNLegacyPass::ID = 0;
4230
4231INITIALIZE_PASS_BEGIN(NewGVNLegacyPass, "newgvn", "Global Value Numbering",static void *initializeNewGVNLegacyPassPassOnce(PassRegistry &
Registry) {
4232 false, false)static void *initializeNewGVNLegacyPassPassOnce(PassRegistry &
Registry) {
4233INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
4234INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
4235INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
4236INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
4237INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
4238INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)initializeGlobalsAAWrapperPassPass(Registry);
4239INITIALIZE_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)); }
4240 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)); }
4241
4242// createGVNPass - The public interface to this file.
4243FunctionPass *llvm::createNewGVNPass() { return new NewGVNLegacyPass(); }
4244
4245PreservedAnalyses NewGVNPass::run(Function &F, AnalysisManager<Function> &AM) {
4246 // Apparently the order in which we get these results matter for
4247 // the old GVN (see Chandler's comment in GVN.cpp). I'll keep
4248 // the same order here, just in case.
4249 auto &AC = AM.getResult<AssumptionAnalysis>(F);
4250 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
4251 auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
4252 auto &AA = AM.getResult<AAManager>(F);
4253 auto &MSSA = AM.getResult<MemorySSAAnalysis>(F).getMSSA();
4254 bool Changed =
4255 NewGVN(F, &DT, &AC, &TLI, &AA, &MSSA, F.getParent()->getDataLayout())
4256 .runGVN();
4257 if (!Changed)
4258 return PreservedAnalyses::all();
4259 PreservedAnalyses PA;
4260 PA.preserve<DominatorTreeAnalysis>();
4261 PA.preserve<GlobalsAA>();
4262 return PA;
4263}