1//===- SCCPSolver.cpp - SCCP Utility --------------------------- *- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// \file
10// This file implements the Sparse Conditional Constant Propagation (SCCP)
11// utility.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Transforms/Utils/SCCPSolver.h"
16#include "llvm/ADT/SetVector.h"
17#include "llvm/Analysis/ConstantFolding.h"
18#include "llvm/Analysis/InstructionSimplify.h"
19#include "llvm/Analysis/ValueLattice.h"
20#include "llvm/Analysis/ValueLatticeUtils.h"
21#include "llvm/Analysis/ValueTracking.h"
22#include "llvm/IR/InstVisitor.h"
23#include "llvm/IR/PatternMatch.h"
24#include "llvm/Support/Casting.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/raw_ostream.h"
28#include "llvm/Transforms/Utils/Local.h"
29#include <cassert>
30#include <utility>
31#include <vector>
32
33using namespace llvm;
34using namespace PatternMatch;
35
36#define DEBUG_TYPE "sccp"
37
38// The maximum number of range extensions allowed for operations requiring
39// widening.
40static const unsigned MaxNumRangeExtensions = 10;
41
42/// Returns MergeOptions with MaxWidenSteps set to MaxNumRangeExtensions.
43static ValueLatticeElement::MergeOptions getMaxWidenStepsOpts() {
44 return ValueLatticeElement::MergeOptions().setMaxWidenSteps(
45 MaxNumRangeExtensions);
46}
47
48namespace llvm {
49
50bool SCCPSolver::isConstant(const ValueLatticeElement &LV) {
51 return LV.isConstant() ||
52 (LV.isConstantRange() && LV.getConstantRange().isSingleElement());
53}
54
55bool SCCPSolver::isOverdefined(const ValueLatticeElement &LV) {
56 return !LV.isUnknownOrUndef() && !SCCPSolver::isConstant(LV);
57}
58
59bool SCCPSolver::tryToReplaceWithConstant(Value *V) {
60 Constant *Const = getConstantOrNull(V);
61 if (!Const)
62 return false;
63 // Replacing `musttail` instructions with constant breaks `musttail` invariant
64 // unless the call itself can be removed.
65 // Calls with "clang.arc.attachedcall" implicitly use the return value and
66 // those uses cannot be updated with a constant.
67 CallBase *CB = dyn_cast<CallBase>(Val: V);
68 if (CB && ((CB->isMustTailCall() && !wouldInstructionBeTriviallyDead(I: CB)) ||
69 CB->getOperandBundle(ID: LLVMContext::OB_clang_arc_attachedcall))) {
70 Function *F = CB->getCalledFunction();
71
72 // Don't zap returns of the callee
73 if (F)
74 addToMustPreserveReturnsInFunctions(F);
75
76 LLVM_DEBUG(dbgs() << " Can\'t treat the result of call " << *CB
77 << " as a constant\n");
78 return false;
79 }
80
81 LLVM_DEBUG(dbgs() << " Constant: " << *Const << " = " << *V << '\n');
82
83 // Replaces all of the uses of a variable with uses of the constant.
84 V->replaceAllUsesWith(V: Const);
85 return true;
86}
87
88/// Helper for getting ranges from \p Solver. Instructions inserted during
89/// simplification are unavailable in the solver, so we return a full range for
90/// them.
91static ConstantRange getRange(Value *Op, SCCPSolver &Solver,
92 const SmallPtrSetImpl<Value *> &InsertedValues) {
93 if (auto *Const = dyn_cast<Constant>(Val: Op))
94 return Const->toConstantRange();
95 if (InsertedValues.contains(Ptr: Op)) {
96 unsigned Bitwidth = Op->getType()->getScalarSizeInBits();
97 return ConstantRange::getFull(BitWidth: Bitwidth);
98 }
99 return Solver.getLatticeValueFor(V: Op).asConstantRange(Ty: Op->getType(),
100 /*UndefAllowed=*/false);
101}
102
103/// Try to use \p Inst's value range from \p Solver to infer the NUW flag.
104static bool refineInstruction(SCCPSolver &Solver,
105 const SmallPtrSetImpl<Value *> &InsertedValues,
106 Instruction &Inst) {
107 bool Changed = false;
108 auto GetRange = [&Solver, &InsertedValues](Value *Op) {
109 return getRange(Op, Solver, InsertedValues);
110 };
111
112 if (isa<OverflowingBinaryOperator>(Val: Inst)) {
113 if (Inst.hasNoSignedWrap() && Inst.hasNoUnsignedWrap())
114 return false;
115
116 auto RangeA = GetRange(Inst.getOperand(i: 0));
117 auto RangeB = GetRange(Inst.getOperand(i: 1));
118 if (!Inst.hasNoUnsignedWrap()) {
119 auto NUWRange = ConstantRange::makeGuaranteedNoWrapRegion(
120 BinOp: Instruction::BinaryOps(Inst.getOpcode()), Other: RangeB,
121 NoWrapKind: OverflowingBinaryOperator::NoUnsignedWrap);
122 if (NUWRange.contains(CR: RangeA)) {
123 Inst.setHasNoUnsignedWrap();
124 Changed = true;
125 }
126 }
127 if (!Inst.hasNoSignedWrap()) {
128 auto NSWRange = ConstantRange::makeGuaranteedNoWrapRegion(
129 BinOp: Instruction::BinaryOps(Inst.getOpcode()), Other: RangeB,
130 NoWrapKind: OverflowingBinaryOperator::NoSignedWrap);
131 if (NSWRange.contains(CR: RangeA)) {
132 Inst.setHasNoSignedWrap();
133 Changed = true;
134 }
135 }
136 } else if (isa<PossiblyNonNegInst>(Val: Inst) && !Inst.hasNonNeg()) {
137 auto Range = GetRange(Inst.getOperand(i: 0));
138 if (Range.isAllNonNegative()) {
139 Inst.setNonNeg();
140 Changed = true;
141 }
142 } else if (TruncInst *TI = dyn_cast<TruncInst>(Val: &Inst)) {
143 if (TI->hasNoSignedWrap() && TI->hasNoUnsignedWrap())
144 return false;
145
146 auto Range = GetRange(Inst.getOperand(i: 0));
147 uint64_t DestWidth = TI->getDestTy()->getScalarSizeInBits();
148 if (!TI->hasNoUnsignedWrap()) {
149 if (Range.getActiveBits() <= DestWidth) {
150 TI->setHasNoUnsignedWrap(true);
151 Changed = true;
152 }
153 }
154 if (!TI->hasNoSignedWrap()) {
155 if (Range.getMinSignedBits() <= DestWidth) {
156 TI->setHasNoSignedWrap(true);
157 Changed = true;
158 }
159 }
160 } else if (auto *GEP = dyn_cast<GetElementPtrInst>(Val: &Inst)) {
161 if (GEP->hasNoUnsignedWrap() || !GEP->hasNoUnsignedSignedWrap())
162 return false;
163
164 if (all_of(Range: GEP->indices(),
165 P: [&](Value *V) { return GetRange(V).isAllNonNegative(); })) {
166 GEP->setNoWrapFlags(GEP->getNoWrapFlags() |
167 GEPNoWrapFlags::noUnsignedWrap());
168 Changed = true;
169 }
170 }
171
172 return Changed;
173}
174
175/// Try to replace signed instructions with their unsigned equivalent.
176static bool replaceSignedInst(SCCPSolver &Solver,
177 SmallPtrSetImpl<Value *> &InsertedValues,
178 Instruction &Inst) {
179 // Determine if a signed value is known to be >= 0.
180 auto isNonNegative = [&Solver, &InsertedValues](Value *V) {
181 return getRange(Op: V, Solver, InsertedValues).isAllNonNegative();
182 };
183
184 Instruction *NewInst = nullptr;
185 switch (Inst.getOpcode()) {
186 case Instruction::SIToFP:
187 case Instruction::SExt: {
188 // If the source value is not negative, this is a zext/uitofp.
189 Value *Op0 = Inst.getOperand(i: 0);
190 if (!isNonNegative(Op0))
191 return false;
192 NewInst = CastInst::Create(Inst.getOpcode() == Instruction::SExt
193 ? Instruction::ZExt
194 : Instruction::UIToFP,
195 S: Op0, Ty: Inst.getType(), Name: "", InsertBefore: Inst.getIterator());
196 NewInst->setNonNeg();
197 break;
198 }
199 case Instruction::AShr: {
200 // If the shifted value is not negative, this is a logical shift right.
201 Value *Op0 = Inst.getOperand(i: 0);
202 if (!isNonNegative(Op0))
203 return false;
204 NewInst = BinaryOperator::CreateLShr(V1: Op0, V2: Inst.getOperand(i: 1), Name: "", InsertBefore: Inst.getIterator());
205 NewInst->setIsExact(Inst.isExact());
206 break;
207 }
208 case Instruction::SDiv:
209 case Instruction::SRem: {
210 // If both operands are not negative, this is the same as udiv/urem.
211 Value *Op0 = Inst.getOperand(i: 0), *Op1 = Inst.getOperand(i: 1);
212 if (!isNonNegative(Op0) || !isNonNegative(Op1))
213 return false;
214 auto NewOpcode = Inst.getOpcode() == Instruction::SDiv ? Instruction::UDiv
215 : Instruction::URem;
216 NewInst = BinaryOperator::Create(Op: NewOpcode, S1: Op0, S2: Op1, Name: "", InsertBefore: Inst.getIterator());
217 if (Inst.getOpcode() == Instruction::SDiv)
218 NewInst->setIsExact(Inst.isExact());
219 break;
220 }
221 default:
222 return false;
223 }
224
225 // Wire up the new instruction and update state.
226 assert(NewInst && "Expected replacement instruction");
227 NewInst->takeName(V: &Inst);
228 InsertedValues.insert(Ptr: NewInst);
229 Inst.replaceAllUsesWith(V: NewInst);
230 NewInst->setDebugLoc(Inst.getDebugLoc());
231 Solver.removeLatticeValueFor(V: &Inst);
232 Inst.eraseFromParent();
233 return true;
234}
235
236/// Try to use \p Inst's value range from \p Solver to simplify it.
237static Value *simplifyInstruction(SCCPSolver &Solver,
238 SmallPtrSetImpl<Value *> &InsertedValues,
239 Instruction &Inst) {
240 auto GetRange = [&Solver, &InsertedValues](Value *Op) {
241 return getRange(Op, Solver, InsertedValues);
242 };
243
244 Value *X;
245 const APInt *RHSC;
246 // Remove masking operations.
247 if (match(V: &Inst, P: m_And(L: m_Value(V&: X), R: m_LowBitMask(V&: RHSC)))) {
248 ConstantRange LRange = GetRange(Inst.getOperand(i: 0));
249 if (LRange.getUnsignedMax().ule(RHS: *RHSC))
250 return X;
251 }
252
253 return nullptr;
254}
255
256bool SCCPSolver::simplifyInstsInBlock(BasicBlock &BB,
257 SmallPtrSetImpl<Value *> &InsertedValues,
258 Statistic &InstRemovedStat,
259 Statistic &InstReplacedStat) {
260 bool MadeChanges = false;
261 for (Instruction &Inst : make_early_inc_range(Range&: BB)) {
262 if (Inst.getType()->isVoidTy())
263 continue;
264 if (tryToReplaceWithConstant(V: &Inst)) {
265 if (wouldInstructionBeTriviallyDead(I: &Inst))
266 Inst.eraseFromParent();
267
268 MadeChanges = true;
269 ++InstRemovedStat;
270 } else if (replaceSignedInst(Solver&: *this, InsertedValues, Inst)) {
271 MadeChanges = true;
272 ++InstReplacedStat;
273 } else if (refineInstruction(Solver&: *this, InsertedValues, Inst)) {
274 MadeChanges = true;
275 } else if (auto *V = simplifyInstruction(Solver&: *this, InsertedValues, Inst)) {
276 Inst.replaceAllUsesWith(V);
277 Inst.eraseFromParent();
278 ++InstRemovedStat;
279 MadeChanges = true;
280 }
281 }
282 return MadeChanges;
283}
284
285bool SCCPSolver::removeNonFeasibleEdges(BasicBlock *BB, DomTreeUpdater &DTU,
286 BasicBlock *&NewUnreachableBB) const {
287 SmallPtrSet<BasicBlock *, 8> FeasibleSuccessors;
288 bool HasNonFeasibleEdges = false;
289 for (BasicBlock *Succ : successors(BB)) {
290 if (isEdgeFeasible(From: BB, To: Succ))
291 FeasibleSuccessors.insert(Ptr: Succ);
292 else
293 HasNonFeasibleEdges = true;
294 }
295
296 // All edges feasible, nothing to do.
297 if (!HasNonFeasibleEdges)
298 return false;
299
300 // SCCP can only determine non-feasible edges for br, switch and indirectbr.
301 Instruction *TI = BB->getTerminator();
302 assert((isa<BranchInst>(TI) || isa<SwitchInst>(TI) ||
303 isa<IndirectBrInst>(TI)) &&
304 "Terminator must be a br, switch or indirectbr");
305
306 if (FeasibleSuccessors.size() == 0) {
307 // Branch on undef/poison, replace with unreachable.
308 SmallPtrSet<BasicBlock *, 8> SeenSuccs;
309 SmallVector<DominatorTree::UpdateType, 8> Updates;
310 for (BasicBlock *Succ : successors(BB)) {
311 Succ->removePredecessor(Pred: BB);
312 if (SeenSuccs.insert(Ptr: Succ).second)
313 Updates.push_back(Elt: {DominatorTree::Delete, BB, Succ});
314 }
315 TI->eraseFromParent();
316 new UnreachableInst(BB->getContext(), BB);
317 DTU.applyUpdatesPermissive(Updates);
318 } else if (FeasibleSuccessors.size() == 1) {
319 // Replace with an unconditional branch to the only feasible successor.
320 BasicBlock *OnlyFeasibleSuccessor = *FeasibleSuccessors.begin();
321 SmallVector<DominatorTree::UpdateType, 8> Updates;
322 bool HaveSeenOnlyFeasibleSuccessor = false;
323 for (BasicBlock *Succ : successors(BB)) {
324 if (Succ == OnlyFeasibleSuccessor && !HaveSeenOnlyFeasibleSuccessor) {
325 // Don't remove the edge to the only feasible successor the first time
326 // we see it. We still do need to remove any multi-edges to it though.
327 HaveSeenOnlyFeasibleSuccessor = true;
328 continue;
329 }
330
331 Succ->removePredecessor(Pred: BB);
332 Updates.push_back(Elt: {DominatorTree::Delete, BB, Succ});
333 }
334
335 Instruction *BI = BranchInst::Create(IfTrue: OnlyFeasibleSuccessor, InsertBefore: BB);
336 BI->setDebugLoc(TI->getDebugLoc());
337 TI->eraseFromParent();
338 DTU.applyUpdatesPermissive(Updates);
339 } else if (FeasibleSuccessors.size() > 1) {
340 SwitchInstProfUpdateWrapper SI(*cast<SwitchInst>(Val: TI));
341 SmallVector<DominatorTree::UpdateType, 8> Updates;
342
343 // If the default destination is unfeasible it will never be taken. Replace
344 // it with a new block with a single Unreachable instruction.
345 BasicBlock *DefaultDest = SI->getDefaultDest();
346 if (!FeasibleSuccessors.contains(Ptr: DefaultDest)) {
347 if (!NewUnreachableBB) {
348 NewUnreachableBB =
349 BasicBlock::Create(Context&: DefaultDest->getContext(), Name: "default.unreachable",
350 Parent: DefaultDest->getParent(), InsertBefore: DefaultDest);
351 auto *UI =
352 new UnreachableInst(DefaultDest->getContext(), NewUnreachableBB);
353 UI->setDebugLoc(DebugLoc::getTemporary());
354 }
355
356 DefaultDest->removePredecessor(Pred: BB);
357 SI->setDefaultDest(NewUnreachableBB);
358 Updates.push_back(Elt: {DominatorTree::Delete, BB, DefaultDest});
359 Updates.push_back(Elt: {DominatorTree::Insert, BB, NewUnreachableBB});
360 }
361
362 for (auto CI = SI->case_begin(); CI != SI->case_end();) {
363 if (FeasibleSuccessors.contains(Ptr: CI->getCaseSuccessor())) {
364 ++CI;
365 continue;
366 }
367
368 BasicBlock *Succ = CI->getCaseSuccessor();
369 Succ->removePredecessor(Pred: BB);
370 Updates.push_back(Elt: {DominatorTree::Delete, BB, Succ});
371 SI.removeCase(I: CI);
372 // Don't increment CI, as we removed a case.
373 }
374
375 DTU.applyUpdatesPermissive(Updates);
376 } else {
377 llvm_unreachable("Must have at least one feasible successor");
378 }
379 return true;
380}
381
382static void inferAttribute(Function *F, unsigned AttrIndex,
383 const ValueLatticeElement &Val) {
384 // If there is a known constant range for the value, add range attribute.
385 if (Val.isConstantRange() && !Val.getConstantRange().isSingleElement()) {
386 // Do not add range attribute if the value may include undef.
387 if (Val.isConstantRangeIncludingUndef())
388 return;
389
390 // Take the intersection of the existing attribute and the inferred range.
391 Attribute OldAttr = F->getAttributeAtIndex(i: AttrIndex, Kind: Attribute::Range);
392 ConstantRange CR = Val.getConstantRange();
393 if (OldAttr.isValid())
394 CR = CR.intersectWith(CR: OldAttr.getRange());
395 F->addAttributeAtIndex(
396 i: AttrIndex, Attr: Attribute::get(Context&: F->getContext(), Kind: Attribute::Range, CR));
397 return;
398 }
399 // Infer nonnull attribute.
400 if (Val.isNotConstant() && Val.getNotConstant()->getType()->isPointerTy() &&
401 Val.getNotConstant()->isNullValue() &&
402 !F->hasAttributeAtIndex(Idx: AttrIndex, Kind: Attribute::NonNull)) {
403 F->addAttributeAtIndex(i: AttrIndex,
404 Attr: Attribute::get(Context&: F->getContext(), Kind: Attribute::NonNull));
405 }
406}
407
408void SCCPSolver::inferReturnAttributes() const {
409 for (const auto &[F, ReturnValue] : getTrackedRetVals())
410 inferAttribute(F, AttrIndex: AttributeList::ReturnIndex, Val: ReturnValue);
411}
412
413void SCCPSolver::inferArgAttributes() const {
414 for (Function *F : getArgumentTrackedFunctions()) {
415 if (!isBlockExecutable(BB: &F->front()))
416 continue;
417 for (Argument &A : F->args())
418 if (!A.getType()->isStructTy())
419 inferAttribute(F, AttrIndex: AttributeList::FirstArgIndex + A.getArgNo(),
420 Val: getLatticeValueFor(V: &A));
421 }
422}
423
424/// Helper class for SCCPSolver. This implements the instruction visitor and
425/// holds all the state.
426class SCCPInstVisitor : public InstVisitor<SCCPInstVisitor> {
427 const DataLayout &DL;
428 std::function<const TargetLibraryInfo &(Function &)> GetTLI;
429 /// Basic blocks that are executable (but may not have been visited yet).
430 SmallPtrSet<BasicBlock *, 8> BBExecutable;
431 /// Basic blocks that are executable and have been visited at least once.
432 SmallPtrSet<BasicBlock *, 8> BBVisited;
433 DenseMap<Value *, ValueLatticeElement>
434 ValueState; // The state each value is in.
435
436 /// StructValueState - This maintains ValueState for values that have
437 /// StructType, for example for formal arguments, calls, insertelement, etc.
438 DenseMap<std::pair<Value *, unsigned>, ValueLatticeElement> StructValueState;
439
440 /// GlobalValue - If we are tracking any values for the contents of a global
441 /// variable, we keep a mapping from the constant accessor to the element of
442 /// the global, to the currently known value. If the value becomes
443 /// overdefined, it's entry is simply removed from this map.
444 DenseMap<GlobalVariable *, ValueLatticeElement> TrackedGlobals;
445
446 /// TrackedRetVals - If we are tracking arguments into and the return
447 /// value out of a function, it will have an entry in this map, indicating
448 /// what the known return value for the function is.
449 MapVector<Function *, ValueLatticeElement> TrackedRetVals;
450
451 /// TrackedMultipleRetVals - Same as TrackedRetVals, but used for functions
452 /// that return multiple values.
453 MapVector<std::pair<Function *, unsigned>, ValueLatticeElement>
454 TrackedMultipleRetVals;
455
456 /// The set of values whose lattice has been invalidated.
457 /// Populated by resetLatticeValueFor(), cleared after resolving undefs.
458 DenseSet<Value *> Invalidated;
459
460 /// MRVFunctionsTracked - Each function in TrackedMultipleRetVals is
461 /// represented here for efficient lookup.
462 SmallPtrSet<Function *, 16> MRVFunctionsTracked;
463
464 /// A list of functions whose return cannot be modified.
465 SmallPtrSet<Function *, 16> MustPreserveReturnsInFunctions;
466
467 /// TrackingIncomingArguments - This is the set of functions for whose
468 /// arguments we make optimistic assumptions about and try to prove as
469 /// constants.
470 SmallPtrSet<Function *, 16> TrackingIncomingArguments;
471
472 /// Worklist of instructions to re-visit. This only includes instructions
473 /// in blocks that have already been visited at least once.
474 SmallSetVector<Instruction *, 16> InstWorkList;
475
476 /// Current instruction while visiting a block for the first time, used to
477 /// avoid unnecessary instruction worklist insertions. Null if an instruction
478 /// is visited outside a whole-block visitation.
479 Instruction *CurI = nullptr;
480
481 // The BasicBlock work list
482 SmallVector<BasicBlock *, 64> BBWorkList;
483
484 /// KnownFeasibleEdges - Entries in this set are edges which have already had
485 /// PHI nodes retriggered.
486 using Edge = std::pair<BasicBlock *, BasicBlock *>;
487 DenseSet<Edge> KnownFeasibleEdges;
488
489 DenseMap<Function *, std::unique_ptr<PredicateInfo>> FnPredicateInfo;
490
491 DenseMap<Value *, SmallSetVector<User *, 2>> AdditionalUsers;
492
493 LLVMContext &Ctx;
494
495 BumpPtrAllocator PredicateInfoAllocator;
496
497private:
498 ConstantInt *getConstantInt(const ValueLatticeElement &IV, Type *Ty) const {
499 return dyn_cast_or_null<ConstantInt>(Val: getConstant(LV: IV, Ty));
500 }
501
502 /// Push instruction \p I to the worklist.
503 void pushToWorkList(Instruction *I);
504
505 /// Push users of value \p V to the worklist.
506 void pushUsersToWorkList(Value *V);
507
508 /// Like pushUsersToWorkList(), but also prints a debug message with the
509 /// updated value.
510 void pushUsersToWorkListMsg(ValueLatticeElement &IV, Value *V);
511
512 // markConstant - Make a value be marked as "constant". If the value
513 // is not already a constant, add it to the instruction work list so that
514 // the users of the instruction are updated later.
515 bool markConstant(ValueLatticeElement &IV, Value *V, Constant *C,
516 bool MayIncludeUndef = false);
517
518 bool markConstant(Value *V, Constant *C) {
519 assert(!V->getType()->isStructTy() && "structs should use mergeInValue");
520 return markConstant(IV&: ValueState[V], V, C);
521 }
522
523 bool markNotConstant(ValueLatticeElement &IV, Value *V, Constant *C);
524
525 bool markNotNull(ValueLatticeElement &IV, Value *V) {
526 return markNotConstant(IV, V, C: Constant::getNullValue(Ty: V->getType()));
527 }
528
529 /// markConstantRange - Mark the object as constant range with \p CR. If the
530 /// object is not a constant range with the range \p CR, add it to the
531 /// instruction work list so that the users of the instruction are updated
532 /// later.
533 bool markConstantRange(ValueLatticeElement &IV, Value *V,
534 const ConstantRange &CR);
535
536 // markOverdefined - Make a value be marked as "overdefined". If the
537 // value is not already overdefined, add it to the overdefined instruction
538 // work list so that the users of the instruction are updated later.
539 bool markOverdefined(ValueLatticeElement &IV, Value *V);
540
541 /// Merge \p MergeWithV into \p IV and push \p V to the worklist, if \p IV
542 /// changes.
543 bool mergeInValue(ValueLatticeElement &IV, Value *V,
544 ValueLatticeElement MergeWithV,
545 ValueLatticeElement::MergeOptions Opts = {
546 /*MayIncludeUndef=*/false, /*CheckWiden=*/false});
547
548 bool mergeInValue(Value *V, ValueLatticeElement MergeWithV,
549 ValueLatticeElement::MergeOptions Opts = {
550 /*MayIncludeUndef=*/false, /*CheckWiden=*/false}) {
551 assert(!V->getType()->isStructTy() &&
552 "non-structs should use markConstant");
553 return mergeInValue(IV&: ValueState[V], V, MergeWithV, Opts);
554 }
555
556 /// getValueState - Return the ValueLatticeElement object that corresponds to
557 /// the value. This function handles the case when the value hasn't been seen
558 /// yet by properly seeding constants etc.
559 ValueLatticeElement &getValueState(Value *V) {
560 assert(!V->getType()->isStructTy() && "Should use getStructValueState");
561
562 auto I = ValueState.try_emplace(Key: V);
563 ValueLatticeElement &LV = I.first->second;
564
565 if (!I.second)
566 return LV; // Common case, already in the map.
567
568 if (auto *C = dyn_cast<Constant>(Val: V))
569 LV.markConstant(V: C); // Constants are constant
570
571 // All others are unknown by default.
572 return LV;
573 }
574
575 /// getStructValueState - Return the ValueLatticeElement object that
576 /// corresponds to the value/field pair. This function handles the case when
577 /// the value hasn't been seen yet by properly seeding constants etc.
578 ValueLatticeElement &getStructValueState(Value *V, unsigned i) {
579 assert(V->getType()->isStructTy() && "Should use getValueState");
580 assert(i < cast<StructType>(V->getType())->getNumElements() &&
581 "Invalid element #");
582
583 auto I = StructValueState.insert(
584 KV: std::make_pair(x: std::make_pair(x&: V, y&: i), y: ValueLatticeElement()));
585 ValueLatticeElement &LV = I.first->second;
586
587 if (!I.second)
588 return LV; // Common case, already in the map.
589
590 if (auto *C = dyn_cast<Constant>(Val: V)) {
591 Constant *Elt = C->getAggregateElement(Elt: i);
592
593 if (!Elt)
594 LV.markOverdefined(); // Unknown sort of constant.
595 else
596 LV.markConstant(V: Elt); // Constants are constant.
597 }
598
599 // All others are underdefined by default.
600 return LV;
601 }
602
603 /// Traverse the use-def chain of \p Call, marking itself and its users as
604 /// "unknown" on the way.
605 void invalidate(CallBase *Call) {
606 SmallVector<Instruction *, 64> ToInvalidate;
607 ToInvalidate.push_back(Elt: Call);
608
609 while (!ToInvalidate.empty()) {
610 Instruction *Inst = ToInvalidate.pop_back_val();
611
612 if (!Invalidated.insert(V: Inst).second)
613 continue;
614
615 if (!BBExecutable.count(Ptr: Inst->getParent()))
616 continue;
617
618 Value *V = nullptr;
619 // For return instructions we need to invalidate the tracked returns map.
620 // Anything else has its lattice in the value map.
621 if (auto *RetInst = dyn_cast<ReturnInst>(Val: Inst)) {
622 Function *F = RetInst->getParent()->getParent();
623 if (auto It = TrackedRetVals.find(Key: F); It != TrackedRetVals.end()) {
624 It->second = ValueLatticeElement();
625 V = F;
626 } else if (MRVFunctionsTracked.count(Ptr: F)) {
627 auto *STy = cast<StructType>(Val: F->getReturnType());
628 for (unsigned I = 0, E = STy->getNumElements(); I != E; ++I)
629 TrackedMultipleRetVals[{F, I}] = ValueLatticeElement();
630 V = F;
631 }
632 } else if (auto *STy = dyn_cast<StructType>(Val: Inst->getType())) {
633 for (unsigned I = 0, E = STy->getNumElements(); I != E; ++I) {
634 if (auto It = StructValueState.find(Val: {Inst, I});
635 It != StructValueState.end()) {
636 It->second = ValueLatticeElement();
637 V = Inst;
638 }
639 }
640 } else if (auto It = ValueState.find(Val: Inst); It != ValueState.end()) {
641 It->second = ValueLatticeElement();
642 V = Inst;
643 }
644
645 if (V) {
646 LLVM_DEBUG(dbgs() << "Invalidated lattice for " << *V << "\n");
647
648 for (User *U : V->users())
649 if (auto *UI = dyn_cast<Instruction>(Val: U))
650 ToInvalidate.push_back(Elt: UI);
651
652 auto It = AdditionalUsers.find(Val: V);
653 if (It != AdditionalUsers.end())
654 for (User *U : It->second)
655 if (auto *UI = dyn_cast<Instruction>(Val: U))
656 ToInvalidate.push_back(Elt: UI);
657 }
658 }
659 }
660
661 /// markEdgeExecutable - Mark a basic block as executable, adding it to the BB
662 /// work list if it is not already executable.
663 bool markEdgeExecutable(BasicBlock *Source, BasicBlock *Dest);
664
665 // getFeasibleSuccessors - Return a vector of booleans to indicate which
666 // successors are reachable from a given terminator instruction.
667 void getFeasibleSuccessors(Instruction &TI, SmallVectorImpl<bool> &Succs);
668
669 // Add U as additional user of V.
670 void addAdditionalUser(Value *V, User *U) { AdditionalUsers[V].insert(X: U); }
671
672 void handleCallOverdefined(CallBase &CB);
673 void handleCallResult(CallBase &CB);
674 void handleCallArguments(CallBase &CB);
675 void handleExtractOfWithOverflow(ExtractValueInst &EVI,
676 const WithOverflowInst *WO, unsigned Idx);
677
678private:
679 friend class InstVisitor<SCCPInstVisitor>;
680
681 // visit implementations - Something changed in this instruction. Either an
682 // operand made a transition, or the instruction is newly executable. Change
683 // the value type of I to reflect these changes if appropriate.
684 void visitPHINode(PHINode &I);
685
686 // Terminators
687
688 void visitReturnInst(ReturnInst &I);
689 void visitTerminator(Instruction &TI);
690
691 void visitCastInst(CastInst &I);
692 void visitSelectInst(SelectInst &I);
693 void visitUnaryOperator(Instruction &I);
694 void visitFreezeInst(FreezeInst &I);
695 void visitBinaryOperator(Instruction &I);
696 void visitCmpInst(CmpInst &I);
697 void visitExtractValueInst(ExtractValueInst &EVI);
698 void visitInsertValueInst(InsertValueInst &IVI);
699
700 void visitCatchSwitchInst(CatchSwitchInst &CPI) {
701 markOverdefined(V: &CPI);
702 visitTerminator(TI&: CPI);
703 }
704
705 // Instructions that cannot be folded away.
706
707 void visitStoreInst(StoreInst &I);
708 void visitLoadInst(LoadInst &I);
709 void visitGetElementPtrInst(GetElementPtrInst &I);
710 void visitAllocaInst(AllocaInst &AI);
711
712 void visitInvokeInst(InvokeInst &II) {
713 visitCallBase(CB&: II);
714 visitTerminator(TI&: II);
715 }
716
717 void visitCallBrInst(CallBrInst &CBI) {
718 visitCallBase(CB&: CBI);
719 visitTerminator(TI&: CBI);
720 }
721
722 void visitCallBase(CallBase &CB);
723 void visitResumeInst(ResumeInst &I) { /*returns void*/
724 }
725 void visitUnreachableInst(UnreachableInst &I) { /*returns void*/
726 }
727 void visitFenceInst(FenceInst &I) { /*returns void*/
728 }
729
730 void visitInstruction(Instruction &I);
731
732public:
733 void addPredicateInfo(Function &F, DominatorTree &DT, AssumptionCache &AC) {
734 FnPredicateInfo.insert(KV: {&F, std::make_unique<PredicateInfo>(
735 args&: F, args&: DT, args&: AC, args&: PredicateInfoAllocator)});
736 }
737
738 void removeSSACopies(Function &F) {
739 auto It = FnPredicateInfo.find(Val: &F);
740 if (It == FnPredicateInfo.end())
741 return;
742
743 for (BasicBlock &BB : F) {
744 for (Instruction &Inst : llvm::make_early_inc_range(Range&: BB)) {
745 if (auto *II = dyn_cast<IntrinsicInst>(Val: &Inst)) {
746 if (II->getIntrinsicID() == Intrinsic::ssa_copy) {
747 if (It->second->getPredicateInfoFor(V: &Inst)) {
748 Value *Op = II->getOperand(i_nocapture: 0);
749 Inst.replaceAllUsesWith(V: Op);
750 Inst.eraseFromParent();
751 }
752 }
753 }
754 }
755 }
756 }
757
758 void visitCallInst(CallInst &I) { visitCallBase(CB&: I); }
759
760 bool markBlockExecutable(BasicBlock *BB);
761
762 const PredicateBase *getPredicateInfoFor(Instruction *I) {
763 auto It = FnPredicateInfo.find(Val: I->getParent()->getParent());
764 if (It == FnPredicateInfo.end())
765 return nullptr;
766 return It->second->getPredicateInfoFor(V: I);
767 }
768
769 SCCPInstVisitor(const DataLayout &DL,
770 std::function<const TargetLibraryInfo &(Function &)> GetTLI,
771 LLVMContext &Ctx)
772 : DL(DL), GetTLI(GetTLI), Ctx(Ctx) {}
773
774 void trackValueOfGlobalVariable(GlobalVariable *GV) {
775 // We only track the contents of scalar globals.
776 if (GV->getValueType()->isSingleValueType()) {
777 ValueLatticeElement &IV = TrackedGlobals[GV];
778 IV.markConstant(V: GV->getInitializer());
779 }
780 }
781
782 void addTrackedFunction(Function *F) {
783 // Add an entry, F -> undef.
784 if (auto *STy = dyn_cast<StructType>(Val: F->getReturnType())) {
785 MRVFunctionsTracked.insert(Ptr: F);
786 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
787 TrackedMultipleRetVals.try_emplace(Key: std::make_pair(x&: F, y&: i));
788 } else if (!F->getReturnType()->isVoidTy())
789 TrackedRetVals.try_emplace(Key: F);
790 }
791
792 void addToMustPreserveReturnsInFunctions(Function *F) {
793 MustPreserveReturnsInFunctions.insert(Ptr: F);
794 }
795
796 bool mustPreserveReturn(Function *F) {
797 return MustPreserveReturnsInFunctions.count(Ptr: F);
798 }
799
800 void addArgumentTrackedFunction(Function *F) {
801 TrackingIncomingArguments.insert(Ptr: F);
802 }
803
804 bool isArgumentTrackedFunction(Function *F) {
805 return TrackingIncomingArguments.count(Ptr: F);
806 }
807
808 const SmallPtrSetImpl<Function *> &getArgumentTrackedFunctions() const {
809 return TrackingIncomingArguments;
810 }
811
812 void solve();
813
814 bool resolvedUndef(Instruction &I);
815
816 bool resolvedUndefsIn(Function &F);
817
818 bool isBlockExecutable(BasicBlock *BB) const {
819 return BBExecutable.count(Ptr: BB);
820 }
821
822 bool isEdgeFeasible(BasicBlock *From, BasicBlock *To) const;
823
824 std::vector<ValueLatticeElement> getStructLatticeValueFor(Value *V) const {
825 std::vector<ValueLatticeElement> StructValues;
826 auto *STy = dyn_cast<StructType>(Val: V->getType());
827 assert(STy && "getStructLatticeValueFor() can be called only on structs");
828 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
829 auto I = StructValueState.find(Val: std::make_pair(x&: V, y&: i));
830 assert(I != StructValueState.end() && "Value not in valuemap!");
831 StructValues.push_back(x: I->second);
832 }
833 return StructValues;
834 }
835
836 void removeLatticeValueFor(Value *V) { ValueState.erase(Val: V); }
837
838 /// Invalidate the Lattice Value of \p Call and its users after specializing
839 /// the call. Then recompute it.
840 void resetLatticeValueFor(CallBase *Call) {
841 // Calls to void returning functions do not need invalidation.
842 Function *F = Call->getCalledFunction();
843 (void)F;
844 assert(!F->getReturnType()->isVoidTy() &&
845 (TrackedRetVals.count(F) || MRVFunctionsTracked.count(F)) &&
846 "All non void specializations should be tracked");
847 invalidate(Call);
848 handleCallResult(CB&: *Call);
849 }
850
851 const ValueLatticeElement &getLatticeValueFor(Value *V) const {
852 assert(!V->getType()->isStructTy() &&
853 "Should use getStructLatticeValueFor");
854 DenseMap<Value *, ValueLatticeElement>::const_iterator I =
855 ValueState.find(Val: V);
856 assert(I != ValueState.end() &&
857 "V not found in ValueState nor Paramstate map!");
858 return I->second;
859 }
860
861 const MapVector<Function *, ValueLatticeElement> &getTrackedRetVals() const {
862 return TrackedRetVals;
863 }
864
865 const DenseMap<GlobalVariable *, ValueLatticeElement> &
866 getTrackedGlobals() const {
867 return TrackedGlobals;
868 }
869
870 const SmallPtrSet<Function *, 16> &getMRVFunctionsTracked() const {
871 return MRVFunctionsTracked;
872 }
873
874 void markOverdefined(Value *V) {
875 if (auto *STy = dyn_cast<StructType>(Val: V->getType()))
876 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
877 markOverdefined(IV&: getStructValueState(V, i), V);
878 else
879 markOverdefined(IV&: ValueState[V], V);
880 }
881
882 ValueLatticeElement getArgAttributeVL(Argument *A) {
883 if (A->getType()->isIntOrIntVectorTy()) {
884 if (std::optional<ConstantRange> Range = A->getRange())
885 return ValueLatticeElement::getRange(CR: *Range);
886 }
887 if (A->hasNonNullAttr())
888 return ValueLatticeElement::getNot(C: Constant::getNullValue(Ty: A->getType()));
889 // Assume nothing about the incoming arguments without attributes.
890 return ValueLatticeElement::getOverdefined();
891 }
892
893 void trackValueOfArgument(Argument *A) {
894 if (A->getType()->isStructTy())
895 return (void)markOverdefined(V: A);
896 mergeInValue(V: A, MergeWithV: getArgAttributeVL(A));
897 }
898
899 bool isStructLatticeConstant(Function *F, StructType *STy);
900
901 Constant *getConstant(const ValueLatticeElement &LV, Type *Ty) const;
902
903 Constant *getConstantOrNull(Value *V) const;
904
905 void setLatticeValueForSpecializationArguments(Function *F,
906 const SmallVectorImpl<ArgInfo> &Args);
907
908 void markFunctionUnreachable(Function *F) {
909 for (auto &BB : *F)
910 BBExecutable.erase(Ptr: &BB);
911 }
912
913 void solveWhileResolvedUndefsIn(Module &M) {
914 bool ResolvedUndefs = true;
915 while (ResolvedUndefs) {
916 solve();
917 ResolvedUndefs = false;
918 for (Function &F : M)
919 ResolvedUndefs |= resolvedUndefsIn(F);
920 }
921 }
922
923 void solveWhileResolvedUndefsIn(SmallVectorImpl<Function *> &WorkList) {
924 bool ResolvedUndefs = true;
925 while (ResolvedUndefs) {
926 solve();
927 ResolvedUndefs = false;
928 for (Function *F : WorkList)
929 ResolvedUndefs |= resolvedUndefsIn(F&: *F);
930 }
931 }
932
933 void solveWhileResolvedUndefs() {
934 bool ResolvedUndefs = true;
935 while (ResolvedUndefs) {
936 solve();
937 ResolvedUndefs = false;
938 for (Value *V : Invalidated)
939 if (auto *I = dyn_cast<Instruction>(Val: V))
940 ResolvedUndefs |= resolvedUndef(I&: *I);
941 }
942 Invalidated.clear();
943 }
944};
945
946} // namespace llvm
947
948bool SCCPInstVisitor::markBlockExecutable(BasicBlock *BB) {
949 if (!BBExecutable.insert(Ptr: BB).second)
950 return false;
951 LLVM_DEBUG(dbgs() << "Marking Block Executable: " << BB->getName() << '\n');
952 BBWorkList.push_back(Elt: BB); // Add the block to the work list!
953 return true;
954}
955
956void SCCPInstVisitor::pushToWorkList(Instruction *I) {
957 // If we're currently visiting a block, do not push any instructions in the
958 // same blocks that are after the current one, as they will be visited
959 // anyway. We do have to push updates to earlier instructions (e.g. phi
960 // nodes or loads of tracked globals).
961 if (CurI && I->getParent() == CurI->getParent() && !I->comesBefore(Other: CurI))
962 return;
963 // Only push instructions in already visited blocks. Otherwise we'll handle
964 // it when we visit the block for the first time.
965 if (BBVisited.contains(Ptr: I->getParent()))
966 InstWorkList.insert(X: I);
967}
968
969void SCCPInstVisitor::pushUsersToWorkList(Value *V) {
970 for (User *U : V->users())
971 if (auto *UI = dyn_cast<Instruction>(Val: U))
972 pushToWorkList(I: UI);
973
974 auto Iter = AdditionalUsers.find(Val: V);
975 if (Iter != AdditionalUsers.end()) {
976 // Copy additional users before notifying them of changes, because new
977 // users may be added, potentially invalidating the iterator.
978 SmallVector<Instruction *, 2> ToNotify;
979 for (User *U : Iter->second)
980 if (auto *UI = dyn_cast<Instruction>(Val: U))
981 ToNotify.push_back(Elt: UI);
982 for (Instruction *UI : ToNotify)
983 pushToWorkList(I: UI);
984 }
985}
986
987void SCCPInstVisitor::pushUsersToWorkListMsg(ValueLatticeElement &IV,
988 Value *V) {
989 LLVM_DEBUG(dbgs() << "updated " << IV << ": " << *V << '\n');
990 pushUsersToWorkList(V);
991}
992
993bool SCCPInstVisitor::markConstant(ValueLatticeElement &IV, Value *V,
994 Constant *C, bool MayIncludeUndef) {
995 if (!IV.markConstant(V: C, MayIncludeUndef))
996 return false;
997 LLVM_DEBUG(dbgs() << "markConstant: " << *C << ": " << *V << '\n');
998 pushUsersToWorkList(V);
999 return true;
1000}
1001
1002bool SCCPInstVisitor::markNotConstant(ValueLatticeElement &IV, Value *V,
1003 Constant *C) {
1004 if (!IV.markNotConstant(V: C))
1005 return false;
1006 LLVM_DEBUG(dbgs() << "markNotConstant: " << *C << ": " << *V << '\n');
1007 pushUsersToWorkList(V);
1008 return true;
1009}
1010
1011bool SCCPInstVisitor::markConstantRange(ValueLatticeElement &IV, Value *V,
1012 const ConstantRange &CR) {
1013 if (!IV.markConstantRange(NewR: CR))
1014 return false;
1015 LLVM_DEBUG(dbgs() << "markConstantRange: " << CR << ": " << *V << '\n');
1016 pushUsersToWorkList(V);
1017 return true;
1018}
1019
1020bool SCCPInstVisitor::markOverdefined(ValueLatticeElement &IV, Value *V) {
1021 if (!IV.markOverdefined())
1022 return false;
1023
1024 LLVM_DEBUG(dbgs() << "markOverdefined: ";
1025 if (auto *F = dyn_cast<Function>(V)) dbgs()
1026 << "Function '" << F->getName() << "'\n";
1027 else dbgs() << *V << '\n');
1028 // Only instructions go on the work list
1029 pushUsersToWorkList(V);
1030 return true;
1031}
1032
1033bool SCCPInstVisitor::isStructLatticeConstant(Function *F, StructType *STy) {
1034 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
1035 const auto &It = TrackedMultipleRetVals.find(Key: std::make_pair(x&: F, y&: i));
1036 assert(It != TrackedMultipleRetVals.end());
1037 ValueLatticeElement LV = It->second;
1038 if (!SCCPSolver::isConstant(LV))
1039 return false;
1040 }
1041 return true;
1042}
1043
1044Constant *SCCPInstVisitor::getConstant(const ValueLatticeElement &LV,
1045 Type *Ty) const {
1046 if (LV.isConstant()) {
1047 Constant *C = LV.getConstant();
1048 assert(C->getType() == Ty && "Type mismatch");
1049 return C;
1050 }
1051
1052 if (LV.isConstantRange()) {
1053 const auto &CR = LV.getConstantRange();
1054 if (CR.getSingleElement())
1055 return ConstantInt::get(Ty, V: *CR.getSingleElement());
1056 }
1057 return nullptr;
1058}
1059
1060Constant *SCCPInstVisitor::getConstantOrNull(Value *V) const {
1061 Constant *Const = nullptr;
1062 if (V->getType()->isStructTy()) {
1063 std::vector<ValueLatticeElement> LVs = getStructLatticeValueFor(V);
1064 if (any_of(Range&: LVs, P: SCCPSolver::isOverdefined))
1065 return nullptr;
1066 std::vector<Constant *> ConstVals;
1067 auto *ST = cast<StructType>(Val: V->getType());
1068 for (unsigned I = 0, E = ST->getNumElements(); I != E; ++I) {
1069 ValueLatticeElement LV = LVs[I];
1070 ConstVals.push_back(x: SCCPSolver::isConstant(LV)
1071 ? getConstant(LV, Ty: ST->getElementType(N: I))
1072 : UndefValue::get(T: ST->getElementType(N: I)));
1073 }
1074 Const = ConstantStruct::get(T: ST, V: ConstVals);
1075 } else {
1076 const ValueLatticeElement &LV = getLatticeValueFor(V);
1077 if (SCCPSolver::isOverdefined(LV))
1078 return nullptr;
1079 Const = SCCPSolver::isConstant(LV) ? getConstant(LV, Ty: V->getType())
1080 : UndefValue::get(T: V->getType());
1081 }
1082 assert(Const && "Constant is nullptr here!");
1083 return Const;
1084}
1085
1086void SCCPInstVisitor::setLatticeValueForSpecializationArguments(Function *F,
1087 const SmallVectorImpl<ArgInfo> &Args) {
1088 assert(!Args.empty() && "Specialization without arguments");
1089 assert(F->arg_size() == Args[0].Formal->getParent()->arg_size() &&
1090 "Functions should have the same number of arguments");
1091
1092 auto Iter = Args.begin();
1093 Function::arg_iterator NewArg = F->arg_begin();
1094 Function::arg_iterator OldArg = Args[0].Formal->getParent()->arg_begin();
1095 for (auto End = F->arg_end(); NewArg != End; ++NewArg, ++OldArg) {
1096
1097 LLVM_DEBUG(dbgs() << "SCCP: Marking argument "
1098 << NewArg->getNameOrAsOperand() << "\n");
1099
1100 // Mark the argument constants in the new function
1101 // or copy the lattice state over from the old function.
1102 if (Iter != Args.end() && Iter->Formal == &*OldArg) {
1103 if (auto *STy = dyn_cast<StructType>(Val: NewArg->getType())) {
1104 for (unsigned I = 0, E = STy->getNumElements(); I != E; ++I) {
1105 ValueLatticeElement &NewValue = StructValueState[{&*NewArg, I}];
1106 NewValue.markConstant(V: Iter->Actual->getAggregateElement(Elt: I));
1107 }
1108 } else {
1109 ValueState[&*NewArg].markConstant(V: Iter->Actual);
1110 }
1111 ++Iter;
1112 } else {
1113 if (auto *STy = dyn_cast<StructType>(Val: NewArg->getType())) {
1114 for (unsigned I = 0, E = STy->getNumElements(); I != E; ++I) {
1115 ValueLatticeElement &NewValue = StructValueState[{&*NewArg, I}];
1116 NewValue = StructValueState[{&*OldArg, I}];
1117 }
1118 } else {
1119 ValueLatticeElement &NewValue = ValueState[&*NewArg];
1120 NewValue = ValueState[&*OldArg];
1121 }
1122 }
1123 }
1124}
1125
1126void SCCPInstVisitor::visitInstruction(Instruction &I) {
1127 // All the instructions we don't do any special handling for just
1128 // go to overdefined.
1129 LLVM_DEBUG(dbgs() << "SCCP: Don't know how to handle: " << I << '\n');
1130 markOverdefined(V: &I);
1131}
1132
1133bool SCCPInstVisitor::mergeInValue(ValueLatticeElement &IV, Value *V,
1134 ValueLatticeElement MergeWithV,
1135 ValueLatticeElement::MergeOptions Opts) {
1136 if (IV.mergeIn(RHS: MergeWithV, Opts)) {
1137 pushUsersToWorkList(V);
1138 LLVM_DEBUG(dbgs() << "Merged " << MergeWithV << " into " << *V << " : "
1139 << IV << "\n");
1140 return true;
1141 }
1142 return false;
1143}
1144
1145bool SCCPInstVisitor::markEdgeExecutable(BasicBlock *Source, BasicBlock *Dest) {
1146 if (!KnownFeasibleEdges.insert(V: Edge(Source, Dest)).second)
1147 return false; // This edge is already known to be executable!
1148
1149 if (!markBlockExecutable(BB: Dest)) {
1150 // If the destination is already executable, we just made an *edge*
1151 // feasible that wasn't before. Revisit the PHI nodes in the block
1152 // because they have potentially new operands.
1153 LLVM_DEBUG(dbgs() << "Marking Edge Executable: " << Source->getName()
1154 << " -> " << Dest->getName() << '\n');
1155
1156 for (PHINode &PN : Dest->phis())
1157 pushToWorkList(I: &PN);
1158 }
1159 return true;
1160}
1161
1162// getFeasibleSuccessors - Return a vector of booleans to indicate which
1163// successors are reachable from a given terminator instruction.
1164void SCCPInstVisitor::getFeasibleSuccessors(Instruction &TI,
1165 SmallVectorImpl<bool> &Succs) {
1166 Succs.resize(N: TI.getNumSuccessors());
1167 if (auto *BI = dyn_cast<BranchInst>(Val: &TI)) {
1168 if (BI->isUnconditional()) {
1169 Succs[0] = true;
1170 return;
1171 }
1172
1173 ValueLatticeElement BCValue = getValueState(V: BI->getCondition());
1174 ConstantInt *CI = getConstantInt(IV: BCValue, Ty: BI->getCondition()->getType());
1175 if (!CI) {
1176 // Overdefined condition variables, and branches on unfoldable constant
1177 // conditions, mean the branch could go either way.
1178 if (!BCValue.isUnknownOrUndef())
1179 Succs[0] = Succs[1] = true;
1180 return;
1181 }
1182
1183 // Constant condition variables mean the branch can only go a single way.
1184 Succs[CI->isZero()] = true;
1185 return;
1186 }
1187
1188 // We cannot analyze special terminators, so consider all successors
1189 // executable.
1190 if (TI.isSpecialTerminator()) {
1191 Succs.assign(NumElts: TI.getNumSuccessors(), Elt: true);
1192 return;
1193 }
1194
1195 if (auto *SI = dyn_cast<SwitchInst>(Val: &TI)) {
1196 if (!SI->getNumCases()) {
1197 Succs[0] = true;
1198 return;
1199 }
1200 const ValueLatticeElement &SCValue = getValueState(V: SI->getCondition());
1201 if (ConstantInt *CI =
1202 getConstantInt(IV: SCValue, Ty: SI->getCondition()->getType())) {
1203 Succs[SI->findCaseValue(C: CI)->getSuccessorIndex()] = true;
1204 return;
1205 }
1206
1207 // TODO: Switch on undef is UB. Stop passing false once the rest of LLVM
1208 // is ready.
1209 if (SCValue.isConstantRange(/*UndefAllowed=*/false)) {
1210 const ConstantRange &Range = SCValue.getConstantRange();
1211 unsigned ReachableCaseCount = 0;
1212 for (const auto &Case : SI->cases()) {
1213 const APInt &CaseValue = Case.getCaseValue()->getValue();
1214 if (Range.contains(Val: CaseValue)) {
1215 Succs[Case.getSuccessorIndex()] = true;
1216 ++ReachableCaseCount;
1217 }
1218 }
1219
1220 Succs[SI->case_default()->getSuccessorIndex()] =
1221 Range.isSizeLargerThan(MaxSize: ReachableCaseCount);
1222 return;
1223 }
1224
1225 // Overdefined or unknown condition? All destinations are executable!
1226 if (!SCValue.isUnknownOrUndef())
1227 Succs.assign(NumElts: TI.getNumSuccessors(), Elt: true);
1228 return;
1229 }
1230
1231 // In case of indirect branch and its address is a blockaddress, we mark
1232 // the target as executable.
1233 if (auto *IBR = dyn_cast<IndirectBrInst>(Val: &TI)) {
1234 // Casts are folded by visitCastInst.
1235 ValueLatticeElement IBRValue = getValueState(V: IBR->getAddress());
1236 BlockAddress *Addr = dyn_cast_or_null<BlockAddress>(
1237 Val: getConstant(LV: IBRValue, Ty: IBR->getAddress()->getType()));
1238 if (!Addr) { // Overdefined or unknown condition?
1239 // All destinations are executable!
1240 if (!IBRValue.isUnknownOrUndef())
1241 Succs.assign(NumElts: TI.getNumSuccessors(), Elt: true);
1242 return;
1243 }
1244
1245 BasicBlock *T = Addr->getBasicBlock();
1246 assert(Addr->getFunction() == T->getParent() &&
1247 "Block address of a different function ?");
1248 for (unsigned i = 0; i < IBR->getNumSuccessors(); ++i) {
1249 // This is the target.
1250 if (IBR->getDestination(i) == T) {
1251 Succs[i] = true;
1252 return;
1253 }
1254 }
1255
1256 // If we didn't find our destination in the IBR successor list, then we
1257 // have undefined behavior. Its ok to assume no successor is executable.
1258 return;
1259 }
1260
1261 LLVM_DEBUG(dbgs() << "Unknown terminator instruction: " << TI << '\n');
1262 llvm_unreachable("SCCP: Don't know how to handle this terminator!");
1263}
1264
1265// isEdgeFeasible - Return true if the control flow edge from the 'From' basic
1266// block to the 'To' basic block is currently feasible.
1267bool SCCPInstVisitor::isEdgeFeasible(BasicBlock *From, BasicBlock *To) const {
1268 // Check if we've called markEdgeExecutable on the edge yet. (We could
1269 // be more aggressive and try to consider edges which haven't been marked
1270 // yet, but there isn't any need.)
1271 return KnownFeasibleEdges.count(V: Edge(From, To));
1272}
1273
1274// visit Implementations - Something changed in this instruction, either an
1275// operand made a transition, or the instruction is newly executable. Change
1276// the value type of I to reflect these changes if appropriate. This method
1277// makes sure to do the following actions:
1278//
1279// 1. If a phi node merges two constants in, and has conflicting value coming
1280// from different branches, or if the PHI node merges in an overdefined
1281// value, then the PHI node becomes overdefined.
1282// 2. If a phi node merges only constants in, and they all agree on value, the
1283// PHI node becomes a constant value equal to that.
1284// 3. If V <- x (op) y && isConstant(x) && isConstant(y) V = Constant
1285// 4. If V <- x (op) y && (isOverdefined(x) || isOverdefined(y)) V = Overdefined
1286// 5. If V <- MEM or V <- CALL or V <- (unknown) then V = Overdefined
1287// 6. If a conditional branch has a value that is constant, make the selected
1288// destination executable
1289// 7. If a conditional branch has a value that is overdefined, make all
1290// successors executable.
1291void SCCPInstVisitor::visitPHINode(PHINode &PN) {
1292 // If this PN returns a struct, just mark the result overdefined.
1293 // TODO: We could do a lot better than this if code actually uses this.
1294 if (PN.getType()->isStructTy())
1295 return (void)markOverdefined(V: &PN);
1296
1297 if (getValueState(V: &PN).isOverdefined())
1298 return; // Quick exit
1299
1300 // Super-extra-high-degree PHI nodes are unlikely to ever be marked constant,
1301 // and slow us down a lot. Just mark them overdefined.
1302 if (PN.getNumIncomingValues() > 64)
1303 return (void)markOverdefined(V: &PN);
1304
1305 unsigned NumActiveIncoming = 0;
1306
1307 // Look at all of the executable operands of the PHI node. If any of them
1308 // are overdefined, the PHI becomes overdefined as well. If they are all
1309 // constant, and they agree with each other, the PHI becomes the identical
1310 // constant. If they are constant and don't agree, the PHI is a constant
1311 // range. If there are no executable operands, the PHI remains unknown.
1312 ValueLatticeElement PhiState = getValueState(V: &PN);
1313 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1314 if (!isEdgeFeasible(From: PN.getIncomingBlock(i), To: PN.getParent()))
1315 continue;
1316
1317 ValueLatticeElement IV = getValueState(V: PN.getIncomingValue(i));
1318 PhiState.mergeIn(RHS: IV);
1319 NumActiveIncoming++;
1320 if (PhiState.isOverdefined())
1321 break;
1322 }
1323
1324 // We allow up to 1 range extension per active incoming value and one
1325 // additional extension. Note that we manually adjust the number of range
1326 // extensions to match the number of active incoming values. This helps to
1327 // limit multiple extensions caused by the same incoming value, if other
1328 // incoming values are equal.
1329 mergeInValue(V: &PN, MergeWithV: PhiState,
1330 Opts: ValueLatticeElement::MergeOptions().setMaxWidenSteps(
1331 NumActiveIncoming + 1));
1332 ValueLatticeElement &PhiStateRef = getValueState(V: &PN);
1333 PhiStateRef.setNumRangeExtensions(
1334 std::max(a: NumActiveIncoming, b: PhiStateRef.getNumRangeExtensions()));
1335}
1336
1337void SCCPInstVisitor::visitReturnInst(ReturnInst &I) {
1338 if (I.getNumOperands() == 0)
1339 return; // ret void
1340
1341 Function *F = I.getParent()->getParent();
1342 Value *ResultOp = I.getOperand(i_nocapture: 0);
1343
1344 // If we are tracking the return value of this function, merge it in.
1345 if (!TrackedRetVals.empty() && !ResultOp->getType()->isStructTy()) {
1346 auto TFRVI = TrackedRetVals.find(Key: F);
1347 if (TFRVI != TrackedRetVals.end()) {
1348 mergeInValue(IV&: TFRVI->second, V: F, MergeWithV: getValueState(V: ResultOp));
1349 return;
1350 }
1351 }
1352
1353 // Handle functions that return multiple values.
1354 if (!TrackedMultipleRetVals.empty()) {
1355 if (auto *STy = dyn_cast<StructType>(Val: ResultOp->getType()))
1356 if (MRVFunctionsTracked.count(Ptr: F))
1357 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1358 mergeInValue(IV&: TrackedMultipleRetVals[std::make_pair(x&: F, y&: i)], V: F,
1359 MergeWithV: getStructValueState(V: ResultOp, i));
1360 }
1361}
1362
1363void SCCPInstVisitor::visitTerminator(Instruction &TI) {
1364 SmallVector<bool, 16> SuccFeasible;
1365 getFeasibleSuccessors(TI, Succs&: SuccFeasible);
1366
1367 BasicBlock *BB = TI.getParent();
1368
1369 // Mark all feasible successors executable.
1370 for (unsigned i = 0, e = SuccFeasible.size(); i != e; ++i)
1371 if (SuccFeasible[i])
1372 markEdgeExecutable(Source: BB, Dest: TI.getSuccessor(Idx: i));
1373}
1374
1375void SCCPInstVisitor::visitCastInst(CastInst &I) {
1376 // ResolvedUndefsIn might mark I as overdefined. Bail out, even if we would
1377 // discover a concrete value later.
1378 if (ValueState[&I].isOverdefined())
1379 return;
1380
1381 ValueLatticeElement OpSt = getValueState(V: I.getOperand(i_nocapture: 0));
1382 if (OpSt.isUnknownOrUndef())
1383 return;
1384
1385 if (Constant *OpC = getConstant(LV: OpSt, Ty: I.getOperand(i_nocapture: 0)->getType())) {
1386 // Fold the constant as we build.
1387 if (Constant *C =
1388 ConstantFoldCastOperand(Opcode: I.getOpcode(), C: OpC, DestTy: I.getType(), DL))
1389 return (void)markConstant(V: &I, C);
1390 }
1391
1392 // Ignore bitcasts, as they may change the number of vector elements.
1393 if (I.getDestTy()->isIntOrIntVectorTy() &&
1394 I.getSrcTy()->isIntOrIntVectorTy() &&
1395 I.getOpcode() != Instruction::BitCast) {
1396 auto &LV = getValueState(V: &I);
1397 ConstantRange OpRange =
1398 OpSt.asConstantRange(Ty: I.getSrcTy(), /*UndefAllowed=*/false);
1399
1400 Type *DestTy = I.getDestTy();
1401 ConstantRange Res =
1402 OpRange.castOp(CastOp: I.getOpcode(), BitWidth: DestTy->getScalarSizeInBits());
1403 mergeInValue(IV&: LV, V: &I, MergeWithV: ValueLatticeElement::getRange(CR: Res));
1404 } else
1405 markOverdefined(V: &I);
1406}
1407
1408void SCCPInstVisitor::handleExtractOfWithOverflow(ExtractValueInst &EVI,
1409 const WithOverflowInst *WO,
1410 unsigned Idx) {
1411 Value *LHS = WO->getLHS(), *RHS = WO->getRHS();
1412 ValueLatticeElement L = getValueState(V: LHS);
1413 ValueLatticeElement R = getValueState(V: RHS);
1414 addAdditionalUser(V: LHS, U: &EVI);
1415 addAdditionalUser(V: RHS, U: &EVI);
1416 if (L.isUnknownOrUndef() || R.isUnknownOrUndef())
1417 return; // Wait to resolve.
1418
1419 Type *Ty = LHS->getType();
1420 ConstantRange LR = L.asConstantRange(Ty, /*UndefAllowed=*/false);
1421 ConstantRange RR = R.asConstantRange(Ty, /*UndefAllowed=*/false);
1422 if (Idx == 0) {
1423 ConstantRange Res = LR.binaryOp(BinOp: WO->getBinaryOp(), Other: RR);
1424 mergeInValue(V: &EVI, MergeWithV: ValueLatticeElement::getRange(CR: Res));
1425 } else {
1426 assert(Idx == 1 && "Index can only be 0 or 1");
1427 ConstantRange NWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
1428 BinOp: WO->getBinaryOp(), Other: RR, NoWrapKind: WO->getNoWrapKind());
1429 if (NWRegion.contains(CR: LR))
1430 return (void)markConstant(V: &EVI, C: ConstantInt::getFalse(Ty: EVI.getType()));
1431 markOverdefined(V: &EVI);
1432 }
1433}
1434
1435void SCCPInstVisitor::visitExtractValueInst(ExtractValueInst &EVI) {
1436 // If this returns a struct, mark all elements over defined, we don't track
1437 // structs in structs.
1438 if (EVI.getType()->isStructTy())
1439 return (void)markOverdefined(V: &EVI);
1440
1441 // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
1442 // discover a concrete value later.
1443 if (ValueState[&EVI].isOverdefined())
1444 return (void)markOverdefined(V: &EVI);
1445
1446 // If this is extracting from more than one level of struct, we don't know.
1447 if (EVI.getNumIndices() != 1)
1448 return (void)markOverdefined(V: &EVI);
1449
1450 Value *AggVal = EVI.getAggregateOperand();
1451 if (AggVal->getType()->isStructTy()) {
1452 unsigned i = *EVI.idx_begin();
1453 if (auto *WO = dyn_cast<WithOverflowInst>(Val: AggVal))
1454 return handleExtractOfWithOverflow(EVI, WO, Idx: i);
1455 ValueLatticeElement EltVal = getStructValueState(V: AggVal, i);
1456 mergeInValue(IV&: getValueState(V: &EVI), V: &EVI, MergeWithV: EltVal);
1457 } else {
1458 // Otherwise, must be extracting from an array.
1459 return (void)markOverdefined(V: &EVI);
1460 }
1461}
1462
1463void SCCPInstVisitor::visitInsertValueInst(InsertValueInst &IVI) {
1464 auto *STy = dyn_cast<StructType>(Val: IVI.getType());
1465 if (!STy)
1466 return (void)markOverdefined(V: &IVI);
1467
1468 // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
1469 // discover a concrete value later.
1470 if (ValueState[&IVI].isOverdefined())
1471 return (void)markOverdefined(V: &IVI);
1472
1473 // If this has more than one index, we can't handle it, drive all results to
1474 // undef.
1475 if (IVI.getNumIndices() != 1)
1476 return (void)markOverdefined(V: &IVI);
1477
1478 Value *Aggr = IVI.getAggregateOperand();
1479 unsigned Idx = *IVI.idx_begin();
1480
1481 // Compute the result based on what we're inserting.
1482 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
1483 // This passes through all values that aren't the inserted element.
1484 if (i != Idx) {
1485 ValueLatticeElement EltVal = getStructValueState(V: Aggr, i);
1486 mergeInValue(IV&: getStructValueState(V: &IVI, i), V: &IVI, MergeWithV: EltVal);
1487 continue;
1488 }
1489
1490 Value *Val = IVI.getInsertedValueOperand();
1491 if (Val->getType()->isStructTy())
1492 // We don't track structs in structs.
1493 markOverdefined(IV&: getStructValueState(V: &IVI, i), V: &IVI);
1494 else {
1495 ValueLatticeElement InVal = getValueState(V: Val);
1496 mergeInValue(IV&: getStructValueState(V: &IVI, i), V: &IVI, MergeWithV: InVal);
1497 }
1498 }
1499}
1500
1501void SCCPInstVisitor::visitSelectInst(SelectInst &I) {
1502 // If this select returns a struct, just mark the result overdefined.
1503 // TODO: We could do a lot better than this if code actually uses this.
1504 if (I.getType()->isStructTy())
1505 return (void)markOverdefined(V: &I);
1506
1507 // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
1508 // discover a concrete value later.
1509 if (ValueState[&I].isOverdefined())
1510 return (void)markOverdefined(V: &I);
1511
1512 ValueLatticeElement CondValue = getValueState(V: I.getCondition());
1513 if (CondValue.isUnknownOrUndef())
1514 return;
1515
1516 if (ConstantInt *CondCB =
1517 getConstantInt(IV: CondValue, Ty: I.getCondition()->getType())) {
1518 Value *OpVal = CondCB->isZero() ? I.getFalseValue() : I.getTrueValue();
1519 mergeInValue(V: &I, MergeWithV: getValueState(V: OpVal));
1520 return;
1521 }
1522
1523 // Otherwise, the condition is overdefined or a constant we can't evaluate.
1524 // See if we can produce something better than overdefined based on the T/F
1525 // value.
1526 ValueLatticeElement TVal = getValueState(V: I.getTrueValue());
1527 ValueLatticeElement FVal = getValueState(V: I.getFalseValue());
1528
1529 ValueLatticeElement &State = ValueState[&I];
1530 bool Changed = State.mergeIn(RHS: TVal);
1531 Changed |= State.mergeIn(RHS: FVal);
1532 if (Changed)
1533 pushUsersToWorkListMsg(IV&: State, V: &I);
1534}
1535
1536// Handle Unary Operators.
1537void SCCPInstVisitor::visitUnaryOperator(Instruction &I) {
1538 ValueLatticeElement V0State = getValueState(V: I.getOperand(i: 0));
1539
1540 ValueLatticeElement &IV = ValueState[&I];
1541 // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
1542 // discover a concrete value later.
1543 if (IV.isOverdefined())
1544 return (void)markOverdefined(V: &I);
1545
1546 // If something is unknown/undef, wait for it to resolve.
1547 if (V0State.isUnknownOrUndef())
1548 return;
1549
1550 if (SCCPSolver::isConstant(LV: V0State))
1551 if (Constant *C = ConstantFoldUnaryOpOperand(
1552 Opcode: I.getOpcode(), Op: getConstant(LV: V0State, Ty: I.getType()), DL))
1553 return (void)markConstant(IV, V: &I, C);
1554
1555 markOverdefined(V: &I);
1556}
1557
1558void SCCPInstVisitor::visitFreezeInst(FreezeInst &I) {
1559 // If this freeze returns a struct, just mark the result overdefined.
1560 // TODO: We could do a lot better than this.
1561 if (I.getType()->isStructTy())
1562 return (void)markOverdefined(V: &I);
1563
1564 ValueLatticeElement V0State = getValueState(V: I.getOperand(i_nocapture: 0));
1565 ValueLatticeElement &IV = ValueState[&I];
1566 // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
1567 // discover a concrete value later.
1568 if (IV.isOverdefined())
1569 return (void)markOverdefined(V: &I);
1570
1571 // If something is unknown/undef, wait for it to resolve.
1572 if (V0State.isUnknownOrUndef())
1573 return;
1574
1575 if (SCCPSolver::isConstant(LV: V0State) &&
1576 isGuaranteedNotToBeUndefOrPoison(V: getConstant(LV: V0State, Ty: I.getType())))
1577 return (void)markConstant(IV, V: &I, C: getConstant(LV: V0State, Ty: I.getType()));
1578
1579 markOverdefined(V: &I);
1580}
1581
1582// Handle Binary Operators.
1583void SCCPInstVisitor::visitBinaryOperator(Instruction &I) {
1584 ValueLatticeElement V1State = getValueState(V: I.getOperand(i: 0));
1585 ValueLatticeElement V2State = getValueState(V: I.getOperand(i: 1));
1586
1587 ValueLatticeElement &IV = ValueState[&I];
1588 if (IV.isOverdefined())
1589 return;
1590
1591 // If something is undef, wait for it to resolve.
1592 if (V1State.isUnknownOrUndef() || V2State.isUnknownOrUndef())
1593 return;
1594
1595 if (V1State.isOverdefined() && V2State.isOverdefined())
1596 return (void)markOverdefined(V: &I);
1597
1598 // If either of the operands is a constant, try to fold it to a constant.
1599 // TODO: Use information from notconstant better.
1600 if ((V1State.isConstant() || V2State.isConstant())) {
1601 Value *V1 = SCCPSolver::isConstant(LV: V1State)
1602 ? getConstant(LV: V1State, Ty: I.getOperand(i: 0)->getType())
1603 : I.getOperand(i: 0);
1604 Value *V2 = SCCPSolver::isConstant(LV: V2State)
1605 ? getConstant(LV: V2State, Ty: I.getOperand(i: 1)->getType())
1606 : I.getOperand(i: 1);
1607 Value *R = simplifyBinOp(Opcode: I.getOpcode(), LHS: V1, RHS: V2, Q: SimplifyQuery(DL, &I));
1608 auto *C = dyn_cast_or_null<Constant>(Val: R);
1609 if (C) {
1610 // Conservatively assume that the result may be based on operands that may
1611 // be undef. Note that we use mergeInValue to combine the constant with
1612 // the existing lattice value for I, as different constants might be found
1613 // after one of the operands go to overdefined, e.g. due to one operand
1614 // being a special floating value.
1615 ValueLatticeElement NewV;
1616 NewV.markConstant(V: C, /*MayIncludeUndef=*/true);
1617 return (void)mergeInValue(V: &I, MergeWithV: NewV);
1618 }
1619 }
1620
1621 // Only use ranges for binary operators on integers.
1622 if (!I.getType()->isIntOrIntVectorTy())
1623 return markOverdefined(V: &I);
1624
1625 // Try to simplify to a constant range.
1626 ConstantRange A =
1627 V1State.asConstantRange(Ty: I.getType(), /*UndefAllowed=*/false);
1628 ConstantRange B =
1629 V2State.asConstantRange(Ty: I.getType(), /*UndefAllowed=*/false);
1630
1631 auto *BO = cast<BinaryOperator>(Val: &I);
1632 ConstantRange R = ConstantRange::getEmpty(BitWidth: I.getType()->getScalarSizeInBits());
1633 if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(Val: BO))
1634 R = A.overflowingBinaryOp(BinOp: BO->getOpcode(), Other: B, NoWrapKind: OBO->getNoWrapKind());
1635 else
1636 R = A.binaryOp(BinOp: BO->getOpcode(), Other: B);
1637 mergeInValue(V: &I, MergeWithV: ValueLatticeElement::getRange(CR: R));
1638
1639 // TODO: Currently we do not exploit special values that produce something
1640 // better than overdefined with an overdefined operand for vector or floating
1641 // point types, like and <4 x i32> overdefined, zeroinitializer.
1642}
1643
1644// Handle ICmpInst instruction.
1645void SCCPInstVisitor::visitCmpInst(CmpInst &I) {
1646 // Do not cache this lookup, getValueState calls later in the function might
1647 // invalidate the reference.
1648 if (ValueState[&I].isOverdefined())
1649 return (void)markOverdefined(V: &I);
1650
1651 Value *Op1 = I.getOperand(i_nocapture: 0);
1652 Value *Op2 = I.getOperand(i_nocapture: 1);
1653
1654 // For parameters, use ParamState which includes constant range info if
1655 // available.
1656 auto V1State = getValueState(V: Op1);
1657 auto V2State = getValueState(V: Op2);
1658
1659 Constant *C = V1State.getCompare(Pred: I.getPredicate(), Ty: I.getType(), Other: V2State, DL);
1660 if (C) {
1661 ValueLatticeElement CV;
1662 CV.markConstant(V: C);
1663 mergeInValue(V: &I, MergeWithV: CV);
1664 return;
1665 }
1666
1667 // If operands are still unknown, wait for it to resolve.
1668 if ((V1State.isUnknownOrUndef() || V2State.isUnknownOrUndef()) &&
1669 !SCCPSolver::isConstant(LV: ValueState[&I]))
1670 return;
1671
1672 markOverdefined(V: &I);
1673}
1674
1675// Handle getelementptr instructions. If all operands are constants then we
1676// can turn this into a getelementptr ConstantExpr.
1677void SCCPInstVisitor::visitGetElementPtrInst(GetElementPtrInst &I) {
1678 if (ValueState[&I].isOverdefined())
1679 return (void)markOverdefined(V: &I);
1680
1681 const ValueLatticeElement &PtrState = getValueState(V: I.getPointerOperand());
1682 if (PtrState.isUnknownOrUndef())
1683 return;
1684
1685 // gep inbounds/nuw of non-null is non-null.
1686 if (PtrState.isNotConstant() && PtrState.getNotConstant()->isNullValue()) {
1687 if (I.hasNoUnsignedWrap() ||
1688 (I.isInBounds() &&
1689 !NullPointerIsDefined(F: I.getFunction(), AS: I.getAddressSpace())))
1690 return (void)markNotNull(IV&: ValueState[&I], V: &I);
1691 return (void)markOverdefined(V: &I);
1692 }
1693
1694 SmallVector<Constant *, 8> Operands;
1695 Operands.reserve(N: I.getNumOperands());
1696
1697 for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
1698 ValueLatticeElement State = getValueState(V: I.getOperand(i_nocapture: i));
1699 if (State.isUnknownOrUndef())
1700 return; // Operands are not resolved yet.
1701
1702 if (Constant *C = getConstant(LV: State, Ty: I.getOperand(i_nocapture: i)->getType())) {
1703 Operands.push_back(Elt: C);
1704 continue;
1705 }
1706
1707 return (void)markOverdefined(V: &I);
1708 }
1709
1710 if (Constant *C = ConstantFoldInstOperands(I: &I, Ops: Operands, DL))
1711 markConstant(V: &I, C);
1712 else
1713 markOverdefined(V: &I);
1714}
1715
1716void SCCPInstVisitor::visitAllocaInst(AllocaInst &I) {
1717 if (!NullPointerIsDefined(F: I.getFunction(), AS: I.getAddressSpace()))
1718 return (void)markNotNull(IV&: ValueState[&I], V: &I);
1719
1720 markOverdefined(V: &I);
1721}
1722
1723void SCCPInstVisitor::visitStoreInst(StoreInst &SI) {
1724 // If this store is of a struct, ignore it.
1725 if (SI.getOperand(i_nocapture: 0)->getType()->isStructTy())
1726 return;
1727
1728 if (TrackedGlobals.empty() || !isa<GlobalVariable>(Val: SI.getOperand(i_nocapture: 1)))
1729 return;
1730
1731 GlobalVariable *GV = cast<GlobalVariable>(Val: SI.getOperand(i_nocapture: 1));
1732 auto I = TrackedGlobals.find(Val: GV);
1733 if (I == TrackedGlobals.end())
1734 return;
1735
1736 // Get the value we are storing into the global, then merge it.
1737 mergeInValue(IV&: I->second, V: GV, MergeWithV: getValueState(V: SI.getOperand(i_nocapture: 0)),
1738 Opts: ValueLatticeElement::MergeOptions().setCheckWiden(false));
1739 if (I->second.isOverdefined())
1740 TrackedGlobals.erase(I); // No need to keep tracking this!
1741}
1742
1743static ValueLatticeElement getValueFromMetadata(const Instruction *I) {
1744 if (const auto *CB = dyn_cast<CallBase>(Val: I)) {
1745 if (CB->getType()->isIntOrIntVectorTy())
1746 if (std::optional<ConstantRange> Range = CB->getRange())
1747 return ValueLatticeElement::getRange(CR: *Range);
1748 if (CB->getType()->isPointerTy() && CB->isReturnNonNull())
1749 return ValueLatticeElement::getNot(
1750 C: ConstantPointerNull::get(T: cast<PointerType>(Val: I->getType())));
1751 }
1752
1753 if (I->getType()->isIntOrIntVectorTy())
1754 if (MDNode *Ranges = I->getMetadata(KindID: LLVMContext::MD_range))
1755 return ValueLatticeElement::getRange(
1756 CR: getConstantRangeFromMetadata(RangeMD: *Ranges));
1757 if (I->hasMetadata(KindID: LLVMContext::MD_nonnull))
1758 return ValueLatticeElement::getNot(
1759 C: ConstantPointerNull::get(T: cast<PointerType>(Val: I->getType())));
1760
1761 return ValueLatticeElement::getOverdefined();
1762}
1763
1764// Handle load instructions. If the operand is a constant pointer to a constant
1765// global, we can replace the load with the loaded constant value!
1766void SCCPInstVisitor::visitLoadInst(LoadInst &I) {
1767 // If this load is of a struct or the load is volatile, just mark the result
1768 // as overdefined.
1769 if (I.getType()->isStructTy() || I.isVolatile())
1770 return (void)markOverdefined(V: &I);
1771
1772 // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
1773 // discover a concrete value later.
1774 if (ValueState[&I].isOverdefined())
1775 return (void)markOverdefined(V: &I);
1776
1777 ValueLatticeElement PtrVal = getValueState(V: I.getOperand(i_nocapture: 0));
1778 if (PtrVal.isUnknownOrUndef())
1779 return; // The pointer is not resolved yet!
1780
1781 ValueLatticeElement &IV = ValueState[&I];
1782
1783 if (SCCPSolver::isConstant(LV: PtrVal)) {
1784 Constant *Ptr = getConstant(LV: PtrVal, Ty: I.getOperand(i_nocapture: 0)->getType());
1785
1786 // load null is undefined.
1787 if (isa<ConstantPointerNull>(Val: Ptr)) {
1788 if (NullPointerIsDefined(F: I.getFunction(), AS: I.getPointerAddressSpace()))
1789 return (void)markOverdefined(IV, V: &I);
1790 else
1791 return;
1792 }
1793
1794 // Transform load (constant global) into the value loaded.
1795 if (auto *GV = dyn_cast<GlobalVariable>(Val: Ptr)) {
1796 if (!TrackedGlobals.empty()) {
1797 // If we are tracking this global, merge in the known value for it.
1798 auto It = TrackedGlobals.find(Val: GV);
1799 if (It != TrackedGlobals.end()) {
1800 mergeInValue(IV, V: &I, MergeWithV: It->second, Opts: getMaxWidenStepsOpts());
1801 return;
1802 }
1803 }
1804 }
1805
1806 // Transform load from a constant into a constant if possible.
1807 if (Constant *C = ConstantFoldLoadFromConstPtr(C: Ptr, Ty: I.getType(), DL))
1808 return (void)markConstant(IV, V: &I, C);
1809 }
1810
1811 // Fall back to metadata.
1812 mergeInValue(V: &I, MergeWithV: getValueFromMetadata(I: &I));
1813}
1814
1815void SCCPInstVisitor::visitCallBase(CallBase &CB) {
1816 handleCallResult(CB);
1817 handleCallArguments(CB);
1818}
1819
1820void SCCPInstVisitor::handleCallOverdefined(CallBase &CB) {
1821 Function *F = CB.getCalledFunction();
1822
1823 // Void return and not tracking callee, just bail.
1824 if (CB.getType()->isVoidTy())
1825 return;
1826
1827 // Always mark struct return as overdefined.
1828 if (CB.getType()->isStructTy())
1829 return (void)markOverdefined(V: &CB);
1830
1831 // Otherwise, if we have a single return value case, and if the function is
1832 // a declaration, maybe we can constant fold it.
1833 if (F && F->isDeclaration() && canConstantFoldCallTo(Call: &CB, F)) {
1834 SmallVector<Constant *, 8> Operands;
1835 for (const Use &A : CB.args()) {
1836 if (A.get()->getType()->isStructTy())
1837 return markOverdefined(V: &CB); // Can't handle struct args.
1838 if (A.get()->getType()->isMetadataTy())
1839 continue; // Carried in CB, not allowed in Operands.
1840 ValueLatticeElement State = getValueState(V: A);
1841
1842 if (State.isUnknownOrUndef())
1843 return; // Operands are not resolved yet.
1844 if (SCCPSolver::isOverdefined(LV: State))
1845 return (void)markOverdefined(V: &CB);
1846 assert(SCCPSolver::isConstant(State) && "Unknown state!");
1847 Operands.push_back(Elt: getConstant(LV: State, Ty: A->getType()));
1848 }
1849
1850 if (SCCPSolver::isOverdefined(LV: getValueState(V: &CB)))
1851 return (void)markOverdefined(V: &CB);
1852
1853 // If we can constant fold this, mark the result of the call as a
1854 // constant.
1855 if (Constant *C = ConstantFoldCall(Call: &CB, F, Operands, TLI: &GetTLI(*F)))
1856 return (void)markConstant(V: &CB, C);
1857 }
1858
1859 // Fall back to metadata.
1860 mergeInValue(V: &CB, MergeWithV: getValueFromMetadata(I: &CB));
1861}
1862
1863void SCCPInstVisitor::handleCallArguments(CallBase &CB) {
1864 Function *F = CB.getCalledFunction();
1865 // If this is a local function that doesn't have its address taken, mark its
1866 // entry block executable and merge in the actual arguments to the call into
1867 // the formal arguments of the function.
1868 if (TrackingIncomingArguments.count(Ptr: F)) {
1869 markBlockExecutable(BB: &F->front());
1870
1871 // Propagate information from this call site into the callee.
1872 auto CAI = CB.arg_begin();
1873 for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end(); AI != E;
1874 ++AI, ++CAI) {
1875 // If this argument is byval, and if the function is not readonly, there
1876 // will be an implicit copy formed of the input aggregate.
1877 if (AI->hasByValAttr() && !F->onlyReadsMemory()) {
1878 markOverdefined(V: &*AI);
1879 continue;
1880 }
1881
1882 if (auto *STy = dyn_cast<StructType>(Val: AI->getType())) {
1883 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
1884 ValueLatticeElement CallArg = getStructValueState(V: *CAI, i);
1885 mergeInValue(IV&: getStructValueState(V: &*AI, i), V: &*AI, MergeWithV: CallArg,
1886 Opts: getMaxWidenStepsOpts());
1887 }
1888 } else
1889 mergeInValue(V: &*AI,
1890 MergeWithV: getValueState(V: *CAI).intersect(Other: getArgAttributeVL(A: &*AI)),
1891 Opts: getMaxWidenStepsOpts());
1892 }
1893 }
1894}
1895
1896void SCCPInstVisitor::handleCallResult(CallBase &CB) {
1897 Function *F = CB.getCalledFunction();
1898
1899 if (auto *II = dyn_cast<IntrinsicInst>(Val: &CB)) {
1900 if (II->getIntrinsicID() == Intrinsic::ssa_copy) {
1901 if (ValueState[&CB].isOverdefined())
1902 return;
1903
1904 Value *CopyOf = CB.getOperand(i_nocapture: 0);
1905 ValueLatticeElement CopyOfVal = getValueState(V: CopyOf);
1906 const auto *PI = getPredicateInfoFor(I: &CB);
1907 assert(PI && "Missing predicate info for ssa.copy");
1908
1909 const std::optional<PredicateConstraint> &Constraint =
1910 PI->getConstraint();
1911 if (!Constraint) {
1912 mergeInValue(IV&: ValueState[&CB], V: &CB, MergeWithV: CopyOfVal);
1913 return;
1914 }
1915
1916 CmpInst::Predicate Pred = Constraint->Predicate;
1917 Value *OtherOp = Constraint->OtherOp;
1918
1919 // Wait until OtherOp is resolved.
1920 if (getValueState(V: OtherOp).isUnknown()) {
1921 addAdditionalUser(V: OtherOp, U: &CB);
1922 return;
1923 }
1924
1925 ValueLatticeElement CondVal = getValueState(V: OtherOp);
1926 ValueLatticeElement &IV = ValueState[&CB];
1927 if (CondVal.isConstantRange() || CopyOfVal.isConstantRange()) {
1928 auto ImposedCR =
1929 ConstantRange::getFull(BitWidth: DL.getTypeSizeInBits(Ty: CopyOf->getType()));
1930
1931 // Get the range imposed by the condition.
1932 if (CondVal.isConstantRange())
1933 ImposedCR = ConstantRange::makeAllowedICmpRegion(
1934 Pred, Other: CondVal.getConstantRange());
1935
1936 // Combine range info for the original value with the new range from the
1937 // condition.
1938 auto CopyOfCR = CopyOfVal.asConstantRange(Ty: CopyOf->getType(),
1939 /*UndefAllowed=*/true);
1940 // Treat an unresolved input like a full range.
1941 if (CopyOfCR.isEmptySet())
1942 CopyOfCR = ConstantRange::getFull(BitWidth: CopyOfCR.getBitWidth());
1943 auto NewCR = ImposedCR.intersectWith(CR: CopyOfCR);
1944 // If the existing information is != x, do not use the information from
1945 // a chained predicate, as the != x information is more likely to be
1946 // helpful in practice.
1947 if (!CopyOfCR.contains(CR: NewCR) && CopyOfCR.getSingleMissingElement())
1948 NewCR = CopyOfCR;
1949
1950 // The new range is based on a branch condition. That guarantees that
1951 // neither of the compare operands can be undef in the branch targets,
1952 // unless we have conditions that are always true/false (e.g. icmp ule
1953 // i32, %a, i32_max). For the latter overdefined/empty range will be
1954 // inferred, but the branch will get folded accordingly anyways.
1955 addAdditionalUser(V: OtherOp, U: &CB);
1956 mergeInValue(
1957 IV, V: &CB,
1958 MergeWithV: ValueLatticeElement::getRange(CR: NewCR, /*MayIncludeUndef*/ false));
1959 return;
1960 } else if (Pred == CmpInst::ICMP_EQ &&
1961 (CondVal.isConstant() || CondVal.isNotConstant())) {
1962 // For non-integer values or integer constant expressions, only
1963 // propagate equal constants or not-constants.
1964 addAdditionalUser(V: OtherOp, U: &CB);
1965 mergeInValue(IV, V: &CB, MergeWithV: CondVal);
1966 return;
1967 } else if (Pred == CmpInst::ICMP_NE && CondVal.isConstant()) {
1968 // Propagate inequalities.
1969 addAdditionalUser(V: OtherOp, U: &CB);
1970 mergeInValue(IV, V: &CB,
1971 MergeWithV: ValueLatticeElement::getNot(C: CondVal.getConstant()));
1972 return;
1973 }
1974
1975 return (void)mergeInValue(IV, V: &CB, MergeWithV: CopyOfVal);
1976 }
1977
1978 if (II->getIntrinsicID() == Intrinsic::vscale) {
1979 unsigned BitWidth = CB.getType()->getScalarSizeInBits();
1980 const ConstantRange Result = getVScaleRange(F: II->getFunction(), BitWidth);
1981 return (void)mergeInValue(V: II, MergeWithV: ValueLatticeElement::getRange(CR: Result));
1982 }
1983
1984 if (ConstantRange::isIntrinsicSupported(IntrinsicID: II->getIntrinsicID())) {
1985 // Compute result range for intrinsics supported by ConstantRange.
1986 // Do this even if we don't know a range for all operands, as we may
1987 // still know something about the result range, e.g. of abs(x).
1988 SmallVector<ConstantRange, 2> OpRanges;
1989 for (Value *Op : II->args()) {
1990 const ValueLatticeElement &State = getValueState(V: Op);
1991 if (State.isUnknownOrUndef())
1992 return;
1993 OpRanges.push_back(
1994 Elt: State.asConstantRange(Ty: Op->getType(), /*UndefAllowed=*/false));
1995 }
1996
1997 ConstantRange Result =
1998 ConstantRange::intrinsic(IntrinsicID: II->getIntrinsicID(), Ops: OpRanges);
1999 return (void)mergeInValue(V: II, MergeWithV: ValueLatticeElement::getRange(CR: Result));
2000 }
2001 }
2002
2003 // The common case is that we aren't tracking the callee, either because we
2004 // are not doing interprocedural analysis or the callee is indirect, or is
2005 // external. Handle these cases first.
2006 if (!F || F->isDeclaration())
2007 return handleCallOverdefined(CB);
2008
2009 // If this is a single/zero retval case, see if we're tracking the function.
2010 if (auto *STy = dyn_cast<StructType>(Val: F->getReturnType())) {
2011 if (!MRVFunctionsTracked.count(Ptr: F))
2012 return handleCallOverdefined(CB); // Not tracking this callee.
2013
2014 // If we are tracking this callee, propagate the result of the function
2015 // into this call site.
2016 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
2017 mergeInValue(IV&: getStructValueState(V: &CB, i), V: &CB,
2018 MergeWithV: TrackedMultipleRetVals[std::make_pair(x&: F, y&: i)],
2019 Opts: getMaxWidenStepsOpts());
2020 } else {
2021 auto TFRVI = TrackedRetVals.find(Key: F);
2022 if (TFRVI == TrackedRetVals.end())
2023 return handleCallOverdefined(CB); // Not tracking this callee.
2024
2025 // If so, propagate the return value of the callee into this call result.
2026 mergeInValue(V: &CB, MergeWithV: TFRVI->second, Opts: getMaxWidenStepsOpts());
2027 }
2028}
2029
2030void SCCPInstVisitor::solve() {
2031 // Process the work lists until they are empty!
2032 while (!BBWorkList.empty() || !InstWorkList.empty()) {
2033 // Process the instruction work list.
2034 while (!InstWorkList.empty()) {
2035 Instruction *I = InstWorkList.pop_back_val();
2036 Invalidated.erase(V: I);
2037
2038 LLVM_DEBUG(dbgs() << "\nPopped off I-WL: " << *I << '\n');
2039
2040 visit(I);
2041 }
2042
2043 // Process the basic block work list.
2044 while (!BBWorkList.empty()) {
2045 BasicBlock *BB = BBWorkList.pop_back_val();
2046 BBVisited.insert(Ptr: BB);
2047
2048 LLVM_DEBUG(dbgs() << "\nPopped off BBWL: " << *BB << '\n');
2049 for (Instruction &I : *BB) {
2050 CurI = &I;
2051 visit(I);
2052 }
2053 CurI = nullptr;
2054 }
2055 }
2056}
2057
2058bool SCCPInstVisitor::resolvedUndef(Instruction &I) {
2059 // Look for instructions which produce undef values.
2060 if (I.getType()->isVoidTy())
2061 return false;
2062
2063 if (auto *STy = dyn_cast<StructType>(Val: I.getType())) {
2064 // Only a few things that can be structs matter for undef.
2065
2066 // Tracked calls must never be marked overdefined in resolvedUndefsIn.
2067 if (auto *CB = dyn_cast<CallBase>(Val: &I))
2068 if (Function *F = CB->getCalledFunction())
2069 if (MRVFunctionsTracked.count(Ptr: F))
2070 return false;
2071
2072 // extractvalue and insertvalue don't need to be marked; they are
2073 // tracked as precisely as their operands.
2074 if (isa<ExtractValueInst>(Val: I) || isa<InsertValueInst>(Val: I))
2075 return false;
2076 // Send the results of everything else to overdefined. We could be
2077 // more precise than this but it isn't worth bothering.
2078 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
2079 ValueLatticeElement &LV = getStructValueState(V: &I, i);
2080 if (LV.isUnknown()) {
2081 markOverdefined(IV&: LV, V: &I);
2082 return true;
2083 }
2084 }
2085 return false;
2086 }
2087
2088 ValueLatticeElement &LV = getValueState(V: &I);
2089 if (!LV.isUnknown())
2090 return false;
2091
2092 // There are two reasons a call can have an undef result
2093 // 1. It could be tracked.
2094 // 2. It could be constant-foldable.
2095 // Because of the way we solve return values, tracked calls must
2096 // never be marked overdefined in resolvedUndefsIn.
2097 if (auto *CB = dyn_cast<CallBase>(Val: &I))
2098 if (Function *F = CB->getCalledFunction())
2099 if (TrackedRetVals.count(Key: F))
2100 return false;
2101
2102 if (isa<LoadInst>(Val: I)) {
2103 // A load here means one of two things: a load of undef from a global,
2104 // a load from an unknown pointer. Either way, having it return undef
2105 // is okay.
2106 return false;
2107 }
2108
2109 markOverdefined(V: &I);
2110 return true;
2111}
2112
2113/// While solving the dataflow for a function, we don't compute a result for
2114/// operations with an undef operand, to allow undef to be lowered to a
2115/// constant later. For example, constant folding of "zext i8 undef to i16"
2116/// would result in "i16 0", and if undef is later lowered to "i8 1", then the
2117/// zext result would become "i16 1" and would result into an overdefined
2118/// lattice value once merged with the previous result. Not computing the
2119/// result of the zext (treating undef the same as unknown) allows us to handle
2120/// a later undef->constant lowering more optimally.
2121///
2122/// However, if the operand remains undef when the solver returns, we do need
2123/// to assign some result to the instruction (otherwise we would treat it as
2124/// unreachable). For simplicity, we mark any instructions that are still
2125/// unknown as overdefined.
2126bool SCCPInstVisitor::resolvedUndefsIn(Function &F) {
2127 bool MadeChange = false;
2128 for (BasicBlock &BB : F) {
2129 if (!BBExecutable.count(Ptr: &BB))
2130 continue;
2131
2132 for (Instruction &I : BB)
2133 MadeChange |= resolvedUndef(I);
2134 }
2135
2136 LLVM_DEBUG(if (MadeChange) dbgs()
2137 << "\nResolved undefs in " << F.getName() << '\n');
2138
2139 return MadeChange;
2140}
2141
2142//===----------------------------------------------------------------------===//
2143//
2144// SCCPSolver implementations
2145//
2146SCCPSolver::SCCPSolver(
2147 const DataLayout &DL,
2148 std::function<const TargetLibraryInfo &(Function &)> GetTLI,
2149 LLVMContext &Ctx)
2150 : Visitor(new SCCPInstVisitor(DL, std::move(GetTLI), Ctx)) {}
2151
2152SCCPSolver::~SCCPSolver() = default;
2153
2154void SCCPSolver::addPredicateInfo(Function &F, DominatorTree &DT,
2155 AssumptionCache &AC) {
2156 Visitor->addPredicateInfo(F, DT, AC);
2157}
2158
2159void SCCPSolver::removeSSACopies(Function &F) {
2160 Visitor->removeSSACopies(F);
2161}
2162
2163bool SCCPSolver::markBlockExecutable(BasicBlock *BB) {
2164 return Visitor->markBlockExecutable(BB);
2165}
2166
2167const PredicateBase *SCCPSolver::getPredicateInfoFor(Instruction *I) {
2168 return Visitor->getPredicateInfoFor(I);
2169}
2170
2171void SCCPSolver::trackValueOfGlobalVariable(GlobalVariable *GV) {
2172 Visitor->trackValueOfGlobalVariable(GV);
2173}
2174
2175void SCCPSolver::addTrackedFunction(Function *F) {
2176 Visitor->addTrackedFunction(F);
2177}
2178
2179void SCCPSolver::addToMustPreserveReturnsInFunctions(Function *F) {
2180 Visitor->addToMustPreserveReturnsInFunctions(F);
2181}
2182
2183bool SCCPSolver::mustPreserveReturn(Function *F) {
2184 return Visitor->mustPreserveReturn(F);
2185}
2186
2187void SCCPSolver::addArgumentTrackedFunction(Function *F) {
2188 Visitor->addArgumentTrackedFunction(F);
2189}
2190
2191bool SCCPSolver::isArgumentTrackedFunction(Function *F) {
2192 return Visitor->isArgumentTrackedFunction(F);
2193}
2194
2195const SmallPtrSetImpl<Function *> &
2196SCCPSolver::getArgumentTrackedFunctions() const {
2197 return Visitor->getArgumentTrackedFunctions();
2198}
2199
2200void SCCPSolver::solve() { Visitor->solve(); }
2201
2202bool SCCPSolver::resolvedUndefsIn(Function &F) {
2203 return Visitor->resolvedUndefsIn(F);
2204}
2205
2206void SCCPSolver::solveWhileResolvedUndefsIn(Module &M) {
2207 Visitor->solveWhileResolvedUndefsIn(M);
2208}
2209
2210void
2211SCCPSolver::solveWhileResolvedUndefsIn(SmallVectorImpl<Function *> &WorkList) {
2212 Visitor->solveWhileResolvedUndefsIn(WorkList);
2213}
2214
2215void SCCPSolver::solveWhileResolvedUndefs() {
2216 Visitor->solveWhileResolvedUndefs();
2217}
2218
2219bool SCCPSolver::isBlockExecutable(BasicBlock *BB) const {
2220 return Visitor->isBlockExecutable(BB);
2221}
2222
2223bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) const {
2224 return Visitor->isEdgeFeasible(From, To);
2225}
2226
2227std::vector<ValueLatticeElement>
2228SCCPSolver::getStructLatticeValueFor(Value *V) const {
2229 return Visitor->getStructLatticeValueFor(V);
2230}
2231
2232void SCCPSolver::removeLatticeValueFor(Value *V) {
2233 return Visitor->removeLatticeValueFor(V);
2234}
2235
2236void SCCPSolver::resetLatticeValueFor(CallBase *Call) {
2237 Visitor->resetLatticeValueFor(Call);
2238}
2239
2240const ValueLatticeElement &SCCPSolver::getLatticeValueFor(Value *V) const {
2241 return Visitor->getLatticeValueFor(V);
2242}
2243
2244const MapVector<Function *, ValueLatticeElement> &
2245SCCPSolver::getTrackedRetVals() const {
2246 return Visitor->getTrackedRetVals();
2247}
2248
2249const DenseMap<GlobalVariable *, ValueLatticeElement> &
2250SCCPSolver::getTrackedGlobals() const {
2251 return Visitor->getTrackedGlobals();
2252}
2253
2254const SmallPtrSet<Function *, 16> &SCCPSolver::getMRVFunctionsTracked() const {
2255 return Visitor->getMRVFunctionsTracked();
2256}
2257
2258void SCCPSolver::markOverdefined(Value *V) { Visitor->markOverdefined(V); }
2259
2260void SCCPSolver::trackValueOfArgument(Argument *V) {
2261 Visitor->trackValueOfArgument(A: V);
2262}
2263
2264bool SCCPSolver::isStructLatticeConstant(Function *F, StructType *STy) {
2265 return Visitor->isStructLatticeConstant(F, STy);
2266}
2267
2268Constant *SCCPSolver::getConstant(const ValueLatticeElement &LV,
2269 Type *Ty) const {
2270 return Visitor->getConstant(LV, Ty);
2271}
2272
2273Constant *SCCPSolver::getConstantOrNull(Value *V) const {
2274 return Visitor->getConstantOrNull(V);
2275}
2276
2277void SCCPSolver::setLatticeValueForSpecializationArguments(Function *F,
2278 const SmallVectorImpl<ArgInfo> &Args) {
2279 Visitor->setLatticeValueForSpecializationArguments(F, Args);
2280}
2281
2282void SCCPSolver::markFunctionUnreachable(Function *F) {
2283 Visitor->markFunctionUnreachable(F);
2284}
2285
2286void SCCPSolver::visit(Instruction *I) { Visitor->visit(I); }
2287
2288void SCCPSolver::visitCall(CallInst &I) { Visitor->visitCall(I); }
2289