1//===- HexagonCommonGEP.cpp -----------------------------------------------===//
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#include "Hexagon.h"
10
11#include "llvm/ADT/ArrayRef.h"
12#include "llvm/ADT/FoldingSet.h"
13#include "llvm/ADT/GraphTraits.h"
14#include "llvm/ADT/STLExtras.h"
15#include "llvm/ADT/SetVector.h"
16#include "llvm/ADT/SmallVector.h"
17#include "llvm/ADT/StringRef.h"
18#include "llvm/Analysis/LoopInfo.h"
19#include "llvm/Analysis/PostDominators.h"
20#include "llvm/IR/BasicBlock.h"
21#include "llvm/IR/Constant.h"
22#include "llvm/IR/Constants.h"
23#include "llvm/IR/DerivedTypes.h"
24#include "llvm/IR/Dominators.h"
25#include "llvm/IR/Function.h"
26#include "llvm/IR/Instruction.h"
27#include "llvm/IR/Instructions.h"
28#include "llvm/IR/Type.h"
29#include "llvm/IR/Use.h"
30#include "llvm/IR/User.h"
31#include "llvm/IR/Value.h"
32#include "llvm/IR/Verifier.h"
33#include "llvm/InitializePasses.h"
34#include "llvm/Pass.h"
35#include "llvm/Support/Allocator.h"
36#include "llvm/Support/Casting.h"
37#include "llvm/Support/CommandLine.h"
38#include "llvm/Support/Compiler.h"
39#include "llvm/Support/Debug.h"
40#include "llvm/Support/raw_ostream.h"
41#include "llvm/Transforms/Utils/Local.h"
42#include <cassert>
43#include <cstddef>
44#include <cstdint>
45#include <iterator>
46#include <map>
47#include <set>
48#include <utility>
49#include <vector>
50
51#define DEBUG_TYPE "commgep"
52
53using namespace llvm;
54
55static cl::opt<bool> OptSpeculate("commgep-speculate", cl::init(Val: true),
56 cl::Hidden);
57
58static cl::opt<bool> OptEnableInv("commgep-inv", cl::init(Val: true), cl::Hidden);
59
60static cl::opt<bool> OptEnableConst("commgep-const", cl::init(Val: true),
61 cl::Hidden);
62
63namespace {
64
65 struct GepNode;
66 using NodeSet = std::set<GepNode *>;
67 using NodeToValueMap = std::map<GepNode *, Value *>;
68 using NodeVect = std::vector<GepNode *>;
69 using NodeChildrenMap = std::map<GepNode *, NodeVect>;
70 using UseSet = SetVector<Use *>;
71 using NodeToUsesMap = std::map<GepNode *, UseSet>;
72
73 // Numbering map for gep nodes. Used to keep track of ordering for
74 // gep nodes.
75 struct NodeOrdering {
76 NodeOrdering() = default;
77
78 void insert(const GepNode *N) { Map.insert(x: std::make_pair(x&: N, y&: ++LastNum)); }
79 void clear() { Map.clear(); }
80
81 bool operator()(const GepNode *N1, const GepNode *N2) const {
82 auto F1 = Map.find(x: N1), F2 = Map.find(x: N2);
83 assert(F1 != Map.end() && F2 != Map.end());
84 return F1->second < F2->second;
85 }
86
87 private:
88 std::map<const GepNode *, unsigned> Map;
89 unsigned LastNum = 0;
90 };
91
92 class HexagonCommonGEP : public FunctionPass {
93 public:
94 static char ID;
95
96 HexagonCommonGEP() : FunctionPass(ID) {}
97
98 bool runOnFunction(Function &F) override;
99 StringRef getPassName() const override { return "Hexagon Common GEP"; }
100
101 void getAnalysisUsage(AnalysisUsage &AU) const override {
102 AU.addRequired<DominatorTreeWrapperPass>();
103 AU.addPreserved<DominatorTreeWrapperPass>();
104 AU.addRequired<PostDominatorTreeWrapperPass>();
105 AU.addPreserved<PostDominatorTreeWrapperPass>();
106 AU.addRequired<LoopInfoWrapperPass>();
107 AU.addPreserved<LoopInfoWrapperPass>();
108 FunctionPass::getAnalysisUsage(AU);
109 }
110
111 private:
112 using ValueToNodeMap = std::map<Value *, GepNode *>;
113 using ValueVect = std::vector<Value *>;
114 using NodeToValuesMap = std::map<GepNode *, ValueVect>;
115
116 void getBlockTraversalOrder(BasicBlock *Root, ValueVect &Order);
117 bool isHandledGepForm(GetElementPtrInst *GepI);
118 void processGepInst(GetElementPtrInst *GepI, ValueToNodeMap &NM);
119 void collect();
120 void common();
121
122 BasicBlock *recalculatePlacement(GepNode *Node, NodeChildrenMap &NCM,
123 NodeToValueMap &Loc);
124 BasicBlock *recalculatePlacementRec(GepNode *Node, NodeChildrenMap &NCM,
125 NodeToValueMap &Loc);
126 bool isInvariantIn(Value *Val, Loop *L);
127 bool isInvariantIn(GepNode *Node, Loop *L);
128 bool isInMainPath(BasicBlock *B, Loop *L);
129 BasicBlock *adjustForInvariance(GepNode *Node, NodeChildrenMap &NCM,
130 NodeToValueMap &Loc);
131 void separateChainForNode(GepNode *Node, Use *U, NodeToValueMap &Loc);
132 void separateConstantChains(GepNode *Node, NodeChildrenMap &NCM,
133 NodeToValueMap &Loc);
134 void computeNodePlacement(NodeToValueMap &Loc);
135
136 Value *fabricateGEP(NodeVect &NA, BasicBlock::iterator At,
137 BasicBlock *LocB);
138 void getAllUsersForNode(GepNode *Node, ValueVect &Values,
139 NodeChildrenMap &NCM);
140 void materialize(NodeToValueMap &Loc);
141
142 void removeDeadCode();
143
144 NodeVect Nodes;
145 NodeToUsesMap Uses;
146 NodeOrdering NodeOrder; // Node ordering, for deterministic behavior.
147 SpecificBumpPtrAllocator<GepNode> *Mem;
148 LLVMContext *Ctx;
149 LoopInfo *LI;
150 DominatorTree *DT;
151 PostDominatorTree *PDT;
152 Function *Fn;
153 };
154
155} // end anonymous namespace
156
157char HexagonCommonGEP::ID = 0;
158
159INITIALIZE_PASS_BEGIN(HexagonCommonGEP, "hcommgep", "Hexagon Common GEP",
160 false, false)
161INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
162INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
163INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
164INITIALIZE_PASS_END(HexagonCommonGEP, "hcommgep", "Hexagon Common GEP",
165 false, false)
166
167namespace {
168
169 struct GepNode {
170 enum {
171 None = 0,
172 Root = 0x01,
173 Internal = 0x02,
174 Used = 0x04,
175 InBounds = 0x08,
176 Pointer = 0x10, // See note below.
177 };
178 // Note: GEP indices generally traverse nested types, and so a GepNode
179 // (representing a single index) can be associated with some composite
180 // type. The exception is the GEP input, which is a pointer, and not
181 // a composite type (at least not in the sense of having sub-types).
182 // Also, the corresponding index plays a different role as well: it is
183 // simply added to the input pointer. Since pointer types are becoming
184 // opaque (i.e. are no longer going to include the pointee type), the
185 // two pieces of information (1) the fact that it's a pointer, and
186 // (2) the pointee type, need to be stored separately. The pointee type
187 // will be stored in the PTy member, while the fact that the node
188 // operates on a pointer will be reflected by the flag "Pointer".
189
190 uint32_t Flags = 0;
191 union {
192 GepNode *Parent;
193 Value *BaseVal;
194 };
195 Value *Idx = nullptr;
196 Type *PTy = nullptr; // Type indexed by this node. For pointer nodes
197 // this is the "pointee" type, and indexing a
198 // pointer does not change the type.
199
200 GepNode() : Parent(nullptr) {}
201 GepNode(const GepNode *N) : Flags(N->Flags), Idx(N->Idx), PTy(N->PTy) {
202 if (Flags & Root)
203 BaseVal = N->BaseVal;
204 else
205 Parent = N->Parent;
206 }
207
208 friend raw_ostream &operator<< (raw_ostream &OS, const GepNode &GN);
209 };
210
211 raw_ostream &operator<< (raw_ostream &OS, const GepNode &GN) {
212 OS << "{ {";
213 bool Comma = false;
214 if (GN.Flags & GepNode::Root) {
215 OS << "root";
216 Comma = true;
217 }
218 if (GN.Flags & GepNode::Internal) {
219 if (Comma)
220 OS << ',';
221 OS << "internal";
222 Comma = true;
223 }
224 if (GN.Flags & GepNode::Used) {
225 if (Comma)
226 OS << ',';
227 OS << "used";
228 }
229 if (GN.Flags & GepNode::InBounds) {
230 if (Comma)
231 OS << ',';
232 OS << "inbounds";
233 }
234 if (GN.Flags & GepNode::Pointer) {
235 if (Comma)
236 OS << ',';
237 OS << "pointer";
238 }
239 OS << "} ";
240 if (GN.Flags & GepNode::Root)
241 OS << "BaseVal:" << GN.BaseVal->getName() << '(' << GN.BaseVal << ')';
242 else
243 OS << "Parent:" << GN.Parent;
244
245 OS << " Idx:";
246 if (ConstantInt *CI = dyn_cast<ConstantInt>(Val: GN.Idx))
247 OS << CI->getValue().getSExtValue();
248 else if (GN.Idx->hasName())
249 OS << GN.Idx->getName();
250 else
251 OS << "<anon> =" << *GN.Idx;
252
253 OS << " PTy:";
254 if (GN.PTy->isStructTy()) {
255 StructType *STy = cast<StructType>(Val: GN.PTy);
256 if (!STy->isLiteral())
257 OS << GN.PTy->getStructName();
258 else
259 OS << "<anon-struct>:" << *STy;
260 }
261 else
262 OS << *GN.PTy;
263 OS << " }";
264 return OS;
265 }
266
267 template <typename NodeContainer>
268 void dump_node_container(raw_ostream &OS, const NodeContainer &S) {
269 using const_iterator = typename NodeContainer::const_iterator;
270
271 for (const_iterator I = S.begin(), E = S.end(); I != E; ++I)
272 OS << *I << ' ' << **I << '\n';
273 }
274
275 [[maybe_unused]] raw_ostream &operator<<(raw_ostream &OS, const NodeVect &S);
276 raw_ostream &operator<< (raw_ostream &OS, const NodeVect &S) {
277 dump_node_container(OS, S);
278 return OS;
279 }
280
281 [[maybe_unused]] raw_ostream &operator<<(raw_ostream &OS,
282 const NodeToUsesMap &M);
283 raw_ostream &operator<< (raw_ostream &OS, const NodeToUsesMap &M){
284 for (const auto &I : M) {
285 const UseSet &Us = I.second;
286 OS << I.first << " -> #" << Us.size() << '{';
287 for (const Use *U : Us) {
288 User *R = U->getUser();
289 if (R->hasName())
290 OS << ' ' << R->getName();
291 else
292 OS << " <?>(" << *R << ')';
293 }
294 OS << " }\n";
295 }
296 return OS;
297 }
298
299 struct in_set {
300 in_set(const NodeSet &S) : NS(S) {}
301
302 bool operator() (GepNode *N) const {
303 return NS.find(x: N) != NS.end();
304 }
305
306 private:
307 const NodeSet &NS;
308 };
309
310} // end anonymous namespace
311
312inline void *operator new(size_t, SpecificBumpPtrAllocator<GepNode> &A) {
313 return A.Allocate();
314}
315
316void HexagonCommonGEP::getBlockTraversalOrder(BasicBlock *Root,
317 ValueVect &Order) {
318 // Compute block ordering for a typical DT-based traversal of the flow
319 // graph: "before visiting a block, all of its dominators must have been
320 // visited".
321
322 Order.push_back(x: Root);
323 for (auto *DTN : children<DomTreeNode*>(G: DT->getNode(BB: Root)))
324 getBlockTraversalOrder(Root: DTN->getBlock(), Order);
325}
326
327bool HexagonCommonGEP::isHandledGepForm(GetElementPtrInst *GepI) {
328 // No vector GEPs.
329 if (!GepI->getType()->isPointerTy())
330 return false;
331 // No GEPs without any indices. (Is this possible?)
332 if (GepI->indices().empty())
333 return false;
334 return true;
335}
336
337void HexagonCommonGEP::processGepInst(GetElementPtrInst *GepI,
338 ValueToNodeMap &NM) {
339 LLVM_DEBUG(dbgs() << "Visiting GEP: " << *GepI << '\n');
340 GepNode *N = new (*Mem) GepNode;
341 Value *PtrOp = GepI->getPointerOperand();
342 uint32_t InBounds = GepI->isInBounds() ? GepNode::InBounds : 0;
343 ValueToNodeMap::iterator F = NM.find(x: PtrOp);
344 if (F == NM.end()) {
345 N->BaseVal = PtrOp;
346 N->Flags |= GepNode::Root | InBounds;
347 } else {
348 // If PtrOp was a GEP instruction, it must have already been processed.
349 // The ValueToNodeMap entry for it is the last gep node in the generated
350 // chain. Link to it here.
351 N->Parent = F->second;
352 }
353 N->PTy = GepI->getSourceElementType();
354 N->Flags |= GepNode::Pointer;
355 N->Idx = *GepI->idx_begin();
356
357 // Collect the list of users of this GEP instruction. Will add it to the
358 // last node created for it.
359 UseSet Us;
360 for (Value::user_iterator UI = GepI->user_begin(), UE = GepI->user_end();
361 UI != UE; ++UI) {
362 // Check if this gep is used by anything other than other geps that
363 // we will process.
364 if (isa<GetElementPtrInst>(Val: *UI)) {
365 GetElementPtrInst *UserG = cast<GetElementPtrInst>(Val: *UI);
366 if (isHandledGepForm(GepI: UserG))
367 continue;
368 }
369 Us.insert(X: &UI.getUse());
370 }
371 Nodes.push_back(x: N);
372 NodeOrder.insert(N);
373
374 // Skip the first index operand, since it was already handled above. This
375 // dereferences the pointer operand.
376 GepNode *PN = N;
377 Type *PtrTy = GepI->getSourceElementType();
378 for (Use &U : llvm::drop_begin(RangeOrContainer: GepI->indices())) {
379 Value *Op = U;
380 GepNode *Nx = new (*Mem) GepNode;
381 Nx->Parent = PN; // Link Nx to the previous node.
382 Nx->Flags |= GepNode::Internal | InBounds;
383 Nx->PTy = PtrTy;
384 Nx->Idx = Op;
385 Nodes.push_back(x: Nx);
386 NodeOrder.insert(N: Nx);
387 PN = Nx;
388
389 PtrTy = GetElementPtrInst::getTypeAtIndex(Ty: PtrTy, Idx: Op);
390 }
391
392 // After last node has been created, update the use information.
393 if (!Us.empty()) {
394 PN->Flags |= GepNode::Used;
395 Uses[PN].insert_range(R&: Us);
396 }
397
398 // Link the last node with the originating GEP instruction. This is to
399 // help with linking chained GEP instructions.
400 NM.insert(x: std::make_pair(x&: GepI, y&: PN));
401}
402
403void HexagonCommonGEP::collect() {
404 // Establish depth-first traversal order of the dominator tree.
405 ValueVect BO;
406 getBlockTraversalOrder(Root: &Fn->front(), Order&: BO);
407
408 // The creation of gep nodes requires DT-traversal. When processing a GEP
409 // instruction that uses another GEP instruction as the base pointer, the
410 // gep node for the base pointer should already exist.
411 ValueToNodeMap NM;
412 for (Value *I : BO) {
413 BasicBlock *B = cast<BasicBlock>(Val: I);
414 for (Instruction &J : *B)
415 if (auto *GepI = dyn_cast<GetElementPtrInst>(Val: &J))
416 if (isHandledGepForm(GepI))
417 processGepInst(GepI, NM);
418 }
419
420 LLVM_DEBUG(dbgs() << "Gep nodes after initial collection:\n" << Nodes);
421}
422
423static void invert_find_roots(const NodeVect &Nodes, NodeChildrenMap &NCM,
424 NodeVect &Roots) {
425 for (GepNode *N : Nodes) {
426 if (N->Flags & GepNode::Root) {
427 Roots.push_back(x: N);
428 continue;
429 }
430 GepNode *PN = N->Parent;
431 NCM[PN].push_back(x: N);
432 }
433}
434
435static void nodes_for_root(GepNode *Root, NodeChildrenMap &NCM,
436 NodeSet &Nodes) {
437 NodeVect Work;
438 Work.push_back(x: Root);
439 Nodes.insert(x: Root);
440
441 while (!Work.empty()) {
442 NodeVect::iterator First = Work.begin();
443 GepNode *N = *First;
444 Work.erase(position: First);
445 NodeChildrenMap::iterator CF = NCM.find(x: N);
446 if (CF != NCM.end()) {
447 llvm::append_range(C&: Work, R&: CF->second);
448 Nodes.insert(first: CF->second.begin(), last: CF->second.end());
449 }
450 }
451}
452
453namespace {
454
455 using NodeSymRel = std::set<NodeSet>;
456 using NodePair = std::pair<GepNode *, GepNode *>;
457 using NodePairSet = std::set<NodePair>;
458
459} // end anonymous namespace
460
461static const NodeSet *node_class(GepNode *N, NodeSymRel &Rel) {
462 for (const NodeSet &S : Rel)
463 if (S.count(x: N))
464 return &S;
465 return nullptr;
466}
467
468 // Create an ordered pair of GepNode pointers. The pair will be used in
469 // determining equality. The only purpose of the ordering is to eliminate
470 // duplication due to the commutativity of equality/non-equality.
471static NodePair node_pair(GepNode *N1, GepNode *N2) {
472 uintptr_t P1 = reinterpret_cast<uintptr_t>(N1);
473 uintptr_t P2 = reinterpret_cast<uintptr_t>(N2);
474 if (P1 <= P2)
475 return std::make_pair(x&: N1, y&: N2);
476 return std::make_pair(x&: N2, y&: N1);
477}
478
479static unsigned node_hash(GepNode *N) {
480 // Include everything except flags and parent.
481 FoldingSetNodeID ID;
482 ID.AddPointer(Ptr: N->Idx);
483 ID.AddPointer(Ptr: N->PTy);
484 return ID.ComputeHash();
485}
486
487static bool node_eq(GepNode *N1, GepNode *N2, NodePairSet &Eq,
488 NodePairSet &Ne) {
489 // Don't cache the result for nodes with different hashes. The hash
490 // comparison is fast enough.
491 if (node_hash(N: N1) != node_hash(N: N2))
492 return false;
493
494 NodePair NP = node_pair(N1, N2);
495 NodePairSet::iterator FEq = Eq.find(x: NP);
496 if (FEq != Eq.end())
497 return true;
498 NodePairSet::iterator FNe = Ne.find(x: NP);
499 if (FNe != Ne.end())
500 return false;
501 // Not previously compared.
502 bool Root1 = N1->Flags & GepNode::Root;
503 uint32_t CmpFlags = GepNode::Root | GepNode::Pointer;
504 bool Different = (N1->Flags & CmpFlags) != (N2->Flags & CmpFlags);
505 NodePair P = node_pair(N1, N2);
506 // If the root/pointer flags have different values, the nodes are
507 // different.
508 // If both nodes are root nodes, but their base pointers differ,
509 // they are different.
510 if (Different || (Root1 && N1->BaseVal != N2->BaseVal)) {
511 Ne.insert(x: P);
512 return false;
513 }
514 // Here the root/pointer flags are identical, and for root nodes the
515 // base pointers are equal, so the root nodes are equal.
516 // For non-root nodes, compare their parent nodes.
517 if (Root1 || node_eq(N1: N1->Parent, N2: N2->Parent, Eq, Ne)) {
518 Eq.insert(x: P);
519 return true;
520 }
521 return false;
522}
523
524void HexagonCommonGEP::common() {
525 // The essence of this commoning is finding gep nodes that are equal.
526 // To do this we need to compare all pairs of nodes. To save time,
527 // first, partition the set of all nodes into sets of potentially equal
528 // nodes, and then compare pairs from within each partition.
529 using NodeSetMap = std::map<unsigned, NodeSet>;
530 NodeSetMap MaybeEq;
531
532 for (GepNode *N : Nodes) {
533 unsigned H = node_hash(N);
534 MaybeEq[H].insert(x: N);
535 }
536
537 // Compute the equivalence relation for the gep nodes. Use two caches,
538 // one for equality and the other for non-equality.
539 NodeSymRel EqRel; // Equality relation (as set of equivalence classes).
540 NodePairSet Eq, Ne; // Caches.
541 for (auto &I : MaybeEq) {
542 NodeSet &S = I.second;
543 for (NodeSet::iterator NI = S.begin(), NE = S.end(); NI != NE; ++NI) {
544 GepNode *N = *NI;
545 // If node already has a class, then the class must have been created
546 // in a prior iteration of this loop. Since equality is transitive,
547 // nothing more will be added to that class, so skip it.
548 if (node_class(N, Rel&: EqRel))
549 continue;
550
551 // Create a new class candidate now.
552 NodeSet C;
553 for (NodeSet::iterator NJ = std::next(x: NI); NJ != NE; ++NJ)
554 if (node_eq(N1: N, N2: *NJ, Eq, Ne))
555 C.insert(x: *NJ);
556 // If Tmp is empty, N would be the only element in it. Don't bother
557 // creating a class for it then.
558 if (!C.empty()) {
559 C.insert(x: N); // Finalize the set before adding it to the relation.
560 std::pair<NodeSymRel::iterator, bool> Ins = EqRel.insert(x: C);
561 (void)Ins;
562 assert(Ins.second && "Cannot add a class");
563 }
564 }
565 }
566
567 LLVM_DEBUG({
568 dbgs() << "Gep node equality:\n";
569 for (NodePairSet::iterator I = Eq.begin(), E = Eq.end(); I != E; ++I)
570 dbgs() << "{ " << I->first << ", " << I->second << " }\n";
571
572 dbgs() << "Gep equivalence classes:\n";
573 for (const NodeSet &S : EqRel) {
574 dbgs() << '{';
575 for (NodeSet::const_iterator J = S.begin(), F = S.end(); J != F; ++J) {
576 if (J != S.begin())
577 dbgs() << ',';
578 dbgs() << ' ' << *J;
579 }
580 dbgs() << " }\n";
581 }
582 });
583
584 // Create a projection from a NodeSet to the minimal element in it.
585 using ProjMap = std::map<const NodeSet *, GepNode *>;
586 ProjMap PM;
587 for (const NodeSet &S : EqRel) {
588 GepNode *Min = *llvm::min_element(Range: S, C: NodeOrder);
589 std::pair<ProjMap::iterator,bool> Ins = PM.insert(x: std::make_pair(x: &S, y&: Min));
590 (void)Ins;
591 assert(Ins.second && "Cannot add minimal element");
592
593 // Update the min element's flags, and user list.
594 uint32_t Flags = 0;
595 UseSet &MinUs = Uses[Min];
596 for (GepNode *N : S) {
597 uint32_t NF = N->Flags;
598 // If N is used, append all original values of N to the list of
599 // original values of Min.
600 if (NF & GepNode::Used) {
601 auto &U = Uses[N];
602 MinUs.insert_range(R&: U);
603 }
604 Flags |= NF;
605 }
606 if (MinUs.empty())
607 Uses.erase(x: Min);
608
609 // The collected flags should include all the flags from the min element.
610 assert((Min->Flags & Flags) == Min->Flags);
611 Min->Flags = Flags;
612 }
613
614 // Commoning: for each non-root gep node, replace "Parent" with the
615 // selected (minimum) node from the corresponding equivalence class.
616 // If a given parent does not have an equivalence class, leave it
617 // unchanged (it means that it's the only element in its class).
618 for (GepNode *N : Nodes) {
619 if (N->Flags & GepNode::Root)
620 continue;
621 const NodeSet *PC = node_class(N: N->Parent, Rel&: EqRel);
622 if (!PC)
623 continue;
624 ProjMap::iterator F = PM.find(x: PC);
625 if (F == PM.end())
626 continue;
627 // Found a replacement, use it.
628 GepNode *Rep = F->second;
629 N->Parent = Rep;
630 }
631
632 LLVM_DEBUG(dbgs() << "Gep nodes after commoning:\n" << Nodes);
633
634 // Finally, erase the nodes that are no longer used.
635 NodeSet Erase;
636 for (GepNode *N : Nodes) {
637 const NodeSet *PC = node_class(N, Rel&: EqRel);
638 if (!PC)
639 continue;
640 ProjMap::iterator F = PM.find(x: PC);
641 if (F == PM.end())
642 continue;
643 if (N == F->second)
644 continue;
645 // Node for removal.
646 Erase.insert(x: N);
647 }
648 erase_if(C&: Nodes, P: in_set(Erase));
649
650 LLVM_DEBUG(dbgs() << "Gep nodes after post-commoning cleanup:\n" << Nodes);
651}
652
653template <typename T>
654static BasicBlock *nearest_common_dominator(DominatorTree *DT, T &Blocks) {
655 LLVM_DEBUG({
656 dbgs() << "NCD of {";
657 for (typename T::iterator I = Blocks.begin(), E = Blocks.end(); I != E;
658 ++I) {
659 if (!*I)
660 continue;
661 BasicBlock *B = cast<BasicBlock>(*I);
662 dbgs() << ' ' << B->getName();
663 }
664 dbgs() << " }\n";
665 });
666
667 // Allow null basic blocks in Blocks. In such cases, return nullptr.
668 typename T::iterator I = Blocks.begin(), E = Blocks.end();
669 if (I == E || !*I)
670 return nullptr;
671 BasicBlock *Dom = cast<BasicBlock>(*I);
672 while (++I != E) {
673 BasicBlock *B = cast_or_null<BasicBlock>(*I);
674 Dom = B ? DT->findNearestCommonDominator(A: Dom, B) : nullptr;
675 if (!Dom)
676 return nullptr;
677 }
678 LLVM_DEBUG(dbgs() << "computed:" << Dom->getName() << '\n');
679 return Dom;
680}
681
682template <typename T>
683static BasicBlock *nearest_common_dominatee(DominatorTree *DT, T &Blocks) {
684 // If two blocks, A and B, dominate a block C, then A dominates B,
685 // or B dominates A.
686 typename T::iterator I = Blocks.begin(), E = Blocks.end();
687 // Find the first non-null block.
688 while (I != E && !*I)
689 ++I;
690 if (I == E)
691 return DT->getRoot();
692 BasicBlock *DomB = cast<BasicBlock>(*I);
693 while (++I != E) {
694 if (!*I)
695 continue;
696 BasicBlock *B = cast<BasicBlock>(*I);
697 if (DT->dominates(A: B, B: DomB))
698 continue;
699 if (!DT->dominates(A: DomB, B))
700 return nullptr;
701 DomB = B;
702 }
703 return DomB;
704}
705
706// Find the first use in B of any value from Values. If no such use,
707// return B->end().
708template <typename T>
709static BasicBlock::iterator first_use_of_in_block(T &Values, BasicBlock *B) {
710 BasicBlock::iterator FirstUse = B->end(), BEnd = B->end();
711
712 using iterator = typename T::iterator;
713
714 for (iterator I = Values.begin(), E = Values.end(); I != E; ++I) {
715 Value *V = *I;
716 // If V is used in a PHI node, the use belongs to the incoming block,
717 // not the block with the PHI node. In the incoming block, the use
718 // would be considered as being at the end of it, so it cannot
719 // influence the position of the first use (which is assumed to be
720 // at the end to start with).
721 if (isa<PHINode>(Val: V))
722 continue;
723 if (!isa<Instruction>(Val: V))
724 continue;
725 Instruction *In = cast<Instruction>(Val: V);
726 if (In->getParent() != B)
727 continue;
728 BasicBlock::iterator It = In->getIterator();
729 if (std::distance(first: FirstUse, last: BEnd) < std::distance(first: It, last: BEnd))
730 FirstUse = It;
731 }
732 return FirstUse;
733}
734
735static bool is_empty(const BasicBlock *B) {
736 return B->empty() || (&*B->begin() == B->getTerminator());
737}
738
739BasicBlock *HexagonCommonGEP::recalculatePlacement(GepNode *Node,
740 NodeChildrenMap &NCM, NodeToValueMap &Loc) {
741 LLVM_DEBUG(dbgs() << "Loc for node:" << Node << '\n');
742 // Recalculate the placement for Node, assuming that the locations of
743 // its children in Loc are valid.
744 // Return nullptr if there is no valid placement for Node (for example, it
745 // uses an index value that is not available at the location required
746 // to dominate all children, etc.).
747
748 // Find the nearest common dominator for:
749 // - all users, if the node is used, and
750 // - all children.
751 ValueVect Bs;
752 if (Node->Flags & GepNode::Used) {
753 // Append all blocks with uses of the original values to the
754 // block vector Bs.
755 NodeToUsesMap::iterator UF = Uses.find(x: Node);
756 assert(UF != Uses.end() && "Used node with no use information");
757 UseSet &Us = UF->second;
758 for (Use *U : Us) {
759 User *R = U->getUser();
760 if (!isa<Instruction>(Val: R))
761 continue;
762 BasicBlock *PB = isa<PHINode>(Val: R)
763 ? cast<PHINode>(Val: R)->getIncomingBlock(U: *U)
764 : cast<Instruction>(Val: R)->getParent();
765 Bs.push_back(x: PB);
766 }
767 }
768 // Append the location of each child.
769 NodeChildrenMap::iterator CF = NCM.find(x: Node);
770 if (CF != NCM.end()) {
771 NodeVect &Cs = CF->second;
772 for (GepNode *CN : Cs) {
773 NodeToValueMap::iterator LF = Loc.find(x: CN);
774 // If the child is only used in GEP instructions (i.e. is not used in
775 // non-GEP instructions), the nearest dominator computed for it may
776 // have been null. In such case it won't have a location available.
777 if (LF == Loc.end())
778 continue;
779 Bs.push_back(x: LF->second);
780 }
781 }
782
783 BasicBlock *DomB = nearest_common_dominator(DT, Blocks&: Bs);
784 if (!DomB)
785 return nullptr;
786 // Check if the index used by Node dominates the computed dominator.
787 Instruction *IdxI = dyn_cast<Instruction>(Val: Node->Idx);
788 if (IdxI && !DT->dominates(A: IdxI->getParent(), B: DomB))
789 return nullptr;
790
791 // Avoid putting nodes into empty blocks.
792 while (is_empty(B: DomB)) {
793 DomTreeNode *N = (*DT)[DomB]->getIDom();
794 if (!N)
795 break;
796 DomB = N->getBlock();
797 }
798
799 // Otherwise, DomB is fine. Update the location map.
800 Loc[Node] = DomB;
801 return DomB;
802}
803
804BasicBlock *HexagonCommonGEP::recalculatePlacementRec(GepNode *Node,
805 NodeChildrenMap &NCM, NodeToValueMap &Loc) {
806 LLVM_DEBUG(dbgs() << "LocRec begin for node:" << Node << '\n');
807 // Recalculate the placement of Node, after recursively recalculating the
808 // placements of all its children.
809 NodeChildrenMap::iterator CF = NCM.find(x: Node);
810 if (CF != NCM.end()) {
811 NodeVect &Cs = CF->second;
812 for (GepNode *C : Cs)
813 recalculatePlacementRec(Node: C, NCM, Loc);
814 }
815 BasicBlock *LB = recalculatePlacement(Node, NCM, Loc);
816 LLVM_DEBUG(dbgs() << "LocRec end for node:" << Node << '\n');
817 return LB;
818}
819
820bool HexagonCommonGEP::isInvariantIn(Value *Val, Loop *L) {
821 if (isa<Constant>(Val) || isa<Argument>(Val))
822 return true;
823 Instruction *In = dyn_cast<Instruction>(Val);
824 if (!In)
825 return false;
826 BasicBlock *HdrB = L->getHeader(), *DefB = In->getParent();
827 return DT->properlyDominates(A: DefB, B: HdrB);
828}
829
830bool HexagonCommonGEP::isInvariantIn(GepNode *Node, Loop *L) {
831 if (Node->Flags & GepNode::Root)
832 if (!isInvariantIn(Val: Node->BaseVal, L))
833 return false;
834 return isInvariantIn(Val: Node->Idx, L);
835}
836
837bool HexagonCommonGEP::isInMainPath(BasicBlock *B, Loop *L) {
838 BasicBlock *HB = L->getHeader();
839 BasicBlock *LB = L->getLoopLatch();
840 // B must post-dominate the loop header or dominate the loop latch.
841 if (PDT->dominates(A: B, B: HB))
842 return true;
843 if (LB && DT->dominates(A: B, B: LB))
844 return true;
845 return false;
846}
847
848static BasicBlock *preheader(DominatorTree *DT, Loop *L) {
849 if (BasicBlock *PH = L->getLoopPreheader())
850 return PH;
851 if (!OptSpeculate)
852 return nullptr;
853 DomTreeNode *DN = DT->getNode(BB: L->getHeader());
854 if (!DN)
855 return nullptr;
856 return DN->getIDom()->getBlock();
857}
858
859BasicBlock *HexagonCommonGEP::adjustForInvariance(GepNode *Node,
860 NodeChildrenMap &NCM, NodeToValueMap &Loc) {
861 // Find the "topmost" location for Node: it must be dominated by both,
862 // its parent (or the BaseVal, if it's a root node), and by the index
863 // value.
864 ValueVect Bs;
865 if (Node->Flags & GepNode::Root) {
866 if (Instruction *PIn = dyn_cast<Instruction>(Val: Node->BaseVal))
867 Bs.push_back(x: PIn->getParent());
868 } else {
869 Bs.push_back(x: Loc[Node->Parent]);
870 }
871 if (Instruction *IIn = dyn_cast<Instruction>(Val: Node->Idx))
872 Bs.push_back(x: IIn->getParent());
873 BasicBlock *TopB = nearest_common_dominatee(DT, Blocks&: Bs);
874
875 // Traverse the loop nest upwards until we find a loop in which Node
876 // is no longer invariant, or until we get to the upper limit of Node's
877 // placement. The traversal will also stop when a suitable "preheader"
878 // cannot be found for a given loop. The "preheader" may actually be
879 // a regular block outside of the loop (i.e. not guarded), in which case
880 // the Node will be speculated.
881 // For nodes that are not in the main path of the containing loop (i.e.
882 // are not executed in each iteration), do not move them out of the loop.
883 BasicBlock *LocB = cast_or_null<BasicBlock>(Val: Loc[Node]);
884 if (LocB) {
885 Loop *Lp = LI->getLoopFor(BB: LocB);
886 while (Lp) {
887 if (!isInvariantIn(Node, L: Lp) || !isInMainPath(B: LocB, L: Lp))
888 break;
889 BasicBlock *NewLoc = preheader(DT, L: Lp);
890 if (!NewLoc || !DT->dominates(A: TopB, B: NewLoc))
891 break;
892 Lp = Lp->getParentLoop();
893 LocB = NewLoc;
894 }
895 }
896 Loc[Node] = LocB;
897
898 // Recursively compute the locations of all children nodes.
899 NodeChildrenMap::iterator CF = NCM.find(x: Node);
900 if (CF != NCM.end()) {
901 NodeVect &Cs = CF->second;
902 for (GepNode *C : Cs)
903 adjustForInvariance(Node: C, NCM, Loc);
904 }
905 return LocB;
906}
907
908namespace {
909
910 struct LocationAsBlock {
911 LocationAsBlock(const NodeToValueMap &L) : Map(L) {}
912
913 const NodeToValueMap &Map;
914 };
915
916 [[maybe_unused]] raw_ostream &operator<<(raw_ostream &OS,
917 const LocationAsBlock &Loc) {
918 for (const auto &I : Loc.Map) {
919 OS << I.first << " -> ";
920 if (BasicBlock *B = cast_or_null<BasicBlock>(Val: I.second))
921 OS << B->getName() << '(' << B << ')';
922 else
923 OS << "<null-block>";
924 OS << '\n';
925 }
926 return OS;
927 }
928
929 inline bool is_constant(GepNode *N) {
930 return isa<ConstantInt>(Val: N->Idx);
931 }
932
933} // end anonymous namespace
934
935void HexagonCommonGEP::separateChainForNode(GepNode *Node, Use *U,
936 NodeToValueMap &Loc) {
937 User *R = U->getUser();
938 LLVM_DEBUG(dbgs() << "Separating chain for node (" << Node << ") user: " << *R
939 << '\n');
940 BasicBlock *PB = cast<Instruction>(Val: R)->getParent();
941
942 GepNode *N = Node;
943 GepNode *C = nullptr, *NewNode = nullptr;
944 while (is_constant(N) && !(N->Flags & GepNode::Root)) {
945 // XXX if (single-use) dont-replicate;
946 GepNode *NewN = new (*Mem) GepNode(N);
947 Nodes.push_back(x: NewN);
948 Loc[NewN] = PB;
949
950 if (N == Node)
951 NewNode = NewN;
952 NewN->Flags &= ~GepNode::Used;
953 if (C)
954 C->Parent = NewN;
955 C = NewN;
956 N = N->Parent;
957 }
958 if (!NewNode)
959 return;
960
961 // Move over all uses that share the same user as U from Node to NewNode.
962 NodeToUsesMap::iterator UF = Uses.find(x: Node);
963 assert(UF != Uses.end());
964 UseSet &Us = UF->second;
965 UseSet NewUs;
966 for (Use *U : Us) {
967 if (U->getUser() == R)
968 NewUs.insert(X: U);
969 }
970 for (Use *U : NewUs)
971 Us.remove(X: U); // erase takes an iterator.
972
973 if (Us.empty()) {
974 Node->Flags &= ~GepNode::Used;
975 Uses.erase(position: UF);
976 }
977
978 // Should at least have U in NewUs.
979 NewNode->Flags |= GepNode::Used;
980 LLVM_DEBUG(dbgs() << "new node: " << NewNode << " " << *NewNode << '\n');
981 assert(!NewUs.empty());
982 Uses[NewNode] = NewUs;
983}
984
985void HexagonCommonGEP::separateConstantChains(GepNode *Node,
986 NodeChildrenMap &NCM, NodeToValueMap &Loc) {
987 // First approximation: extract all chains.
988 NodeSet Ns;
989 nodes_for_root(Root: Node, NCM, Nodes&: Ns);
990
991 LLVM_DEBUG(dbgs() << "Separating constant chains for node: " << Node << '\n');
992 // Collect all used nodes together with the uses from loads and stores,
993 // where the GEP node could be folded into the load/store instruction.
994 NodeToUsesMap FNs; // Foldable nodes.
995 for (GepNode *N : Ns) {
996 if (!(N->Flags & GepNode::Used))
997 continue;
998 NodeToUsesMap::iterator UF = Uses.find(x: N);
999 assert(UF != Uses.end());
1000 UseSet &Us = UF->second;
1001 // Loads/stores that use the node N.
1002 UseSet LSs;
1003 for (Use *U : Us) {
1004 User *R = U->getUser();
1005 // We're interested in uses that provide the address. It can happen
1006 // that the value may also be provided via GEP, but we won't handle
1007 // those cases here for now.
1008 if (LoadInst *Ld = dyn_cast<LoadInst>(Val: R)) {
1009 unsigned PtrX = LoadInst::getPointerOperandIndex();
1010 if (&Ld->getOperandUse(i: PtrX) == U)
1011 LSs.insert(X: U);
1012 } else if (StoreInst *St = dyn_cast<StoreInst>(Val: R)) {
1013 unsigned PtrX = StoreInst::getPointerOperandIndex();
1014 if (&St->getOperandUse(i: PtrX) == U)
1015 LSs.insert(X: U);
1016 }
1017 }
1018 // Even if the total use count is 1, separating the chain may still be
1019 // beneficial, since the constant chain may be longer than the GEP alone
1020 // would be (e.g. if the parent node has a constant index and also has
1021 // other children).
1022 if (!LSs.empty())
1023 FNs.insert(x: std::make_pair(x&: N, y&: LSs));
1024 }
1025
1026 LLVM_DEBUG(dbgs() << "Nodes with foldable users:\n" << FNs);
1027
1028 for (auto &FN : FNs) {
1029 GepNode *N = FN.first;
1030 UseSet &Us = FN.second;
1031 for (Use *U : Us)
1032 separateChainForNode(Node: N, U, Loc);
1033 }
1034}
1035
1036void HexagonCommonGEP::computeNodePlacement(NodeToValueMap &Loc) {
1037 // Compute the inverse of the Node.Parent links. Also, collect the set
1038 // of root nodes.
1039 NodeChildrenMap NCM;
1040 NodeVect Roots;
1041 invert_find_roots(Nodes, NCM, Roots);
1042
1043 // Compute the initial placement determined by the users' locations, and
1044 // the locations of the child nodes.
1045 for (GepNode *Root : Roots)
1046 recalculatePlacementRec(Node: Root, NCM, Loc);
1047
1048 LLVM_DEBUG(dbgs() << "Initial node placement:\n" << LocationAsBlock(Loc));
1049
1050 if (OptEnableInv) {
1051 for (GepNode *Root : Roots)
1052 adjustForInvariance(Node: Root, NCM, Loc);
1053
1054 LLVM_DEBUG(dbgs() << "Node placement after adjustment for invariance:\n"
1055 << LocationAsBlock(Loc));
1056 }
1057 if (OptEnableConst) {
1058 for (GepNode *Root : Roots)
1059 separateConstantChains(Node: Root, NCM, Loc);
1060 }
1061 LLVM_DEBUG(dbgs() << "Node use information:\n" << Uses);
1062
1063 // At the moment, there is no further refinement of the initial placement.
1064 // Such a refinement could include splitting the nodes if they are placed
1065 // too far from some of its users.
1066
1067 LLVM_DEBUG(dbgs() << "Final node placement:\n" << LocationAsBlock(Loc));
1068}
1069
1070Value *HexagonCommonGEP::fabricateGEP(NodeVect &NA, BasicBlock::iterator At,
1071 BasicBlock *LocB) {
1072 LLVM_DEBUG(dbgs() << "Fabricating GEP in " << LocB->getName()
1073 << " for nodes:\n"
1074 << NA);
1075 unsigned Num = NA.size();
1076 GepNode *RN = NA[0];
1077 assert((RN->Flags & GepNode::Root) && "Creating GEP for non-root");
1078
1079 GetElementPtrInst *NewInst = nullptr;
1080 Value *Input = RN->BaseVal;
1081 Type *InpTy = RN->PTy;
1082
1083 unsigned Idx = 0;
1084 do {
1085 SmallVector<Value*, 4> IdxList;
1086 // If the type of the input of the first node is not a pointer,
1087 // we need to add an artificial i32 0 to the indices (because the
1088 // actual input in the IR will be a pointer).
1089 if (!(NA[Idx]->Flags & GepNode::Pointer)) {
1090 Type *Int32Ty = Type::getInt32Ty(C&: *Ctx);
1091 IdxList.push_back(Elt: ConstantInt::get(Ty: Int32Ty, V: 0));
1092 }
1093
1094 // Keep adding indices from NA until we have to stop and generate
1095 // an "intermediate" GEP.
1096 while (++Idx <= Num) {
1097 GepNode *N = NA[Idx-1];
1098 IdxList.push_back(Elt: N->Idx);
1099 if (Idx < Num) {
1100 // We have to stop if we reach a pointer.
1101 if (NA[Idx]->Flags & GepNode::Pointer)
1102 break;
1103 }
1104 }
1105 NewInst = GetElementPtrInst::Create(PointeeType: InpTy, Ptr: Input, IdxList, NameStr: "cgep", InsertBefore: At);
1106 NewInst->setIsInBounds(RN->Flags & GepNode::InBounds);
1107 LLVM_DEBUG(dbgs() << "new GEP: " << *NewInst << '\n');
1108 if (Idx < Num) {
1109 Input = NewInst;
1110 InpTy = NA[Idx]->PTy;
1111 }
1112 } while (Idx <= Num);
1113
1114 return NewInst;
1115}
1116
1117void HexagonCommonGEP::getAllUsersForNode(GepNode *Node, ValueVect &Values,
1118 NodeChildrenMap &NCM) {
1119 NodeVect Work;
1120 Work.push_back(x: Node);
1121
1122 while (!Work.empty()) {
1123 NodeVect::iterator First = Work.begin();
1124 GepNode *N = *First;
1125 Work.erase(position: First);
1126 if (N->Flags & GepNode::Used) {
1127 NodeToUsesMap::iterator UF = Uses.find(x: N);
1128 assert(UF != Uses.end() && "No use information for used node");
1129 UseSet &Us = UF->second;
1130 for (const auto &U : Us)
1131 Values.push_back(x: U->getUser());
1132 }
1133 NodeChildrenMap::iterator CF = NCM.find(x: N);
1134 if (CF != NCM.end()) {
1135 NodeVect &Cs = CF->second;
1136 llvm::append_range(C&: Work, R&: Cs);
1137 }
1138 }
1139}
1140
1141void HexagonCommonGEP::materialize(NodeToValueMap &Loc) {
1142 LLVM_DEBUG(dbgs() << "Nodes before materialization:\n" << Nodes << '\n');
1143 NodeChildrenMap NCM;
1144 NodeVect Roots;
1145 // Compute the inversion again, since computing placement could alter
1146 // "parent" relation between nodes.
1147 invert_find_roots(Nodes, NCM, Roots);
1148
1149 while (!Roots.empty()) {
1150 NodeVect::iterator First = Roots.begin();
1151 GepNode *Root = *First, *Last = *First;
1152 Roots.erase(position: First);
1153
1154 NodeVect NA; // Nodes to assemble.
1155 // Append to NA all child nodes up to (and including) the first child
1156 // that:
1157 // (1) has more than 1 child, or
1158 // (2) is used, or
1159 // (3) has a child located in a different block.
1160 bool LastUsed = false;
1161 unsigned LastCN = 0;
1162 // The location may be null if the computation failed (it can legitimately
1163 // happen for nodes created from dead GEPs).
1164 Value *LocV = Loc[Last];
1165 if (!LocV)
1166 continue;
1167 BasicBlock *LastB = cast<BasicBlock>(Val: LocV);
1168 do {
1169 NA.push_back(x: Last);
1170 LastUsed = (Last->Flags & GepNode::Used);
1171 if (LastUsed)
1172 break;
1173 NodeChildrenMap::iterator CF = NCM.find(x: Last);
1174 LastCN = (CF != NCM.end()) ? CF->second.size() : 0;
1175 if (LastCN != 1)
1176 break;
1177 GepNode *Child = CF->second.front();
1178 BasicBlock *ChildB = cast_or_null<BasicBlock>(Val: Loc[Child]);
1179 if (ChildB != nullptr && LastB != ChildB)
1180 break;
1181 Last = Child;
1182 } while (true);
1183
1184 BasicBlock::iterator InsertAt = LastB->getTerminator()->getIterator();
1185 if (LastUsed || LastCN > 0) {
1186 ValueVect Urs;
1187 getAllUsersForNode(Node: Root, Values&: Urs, NCM);
1188 BasicBlock::iterator FirstUse = first_use_of_in_block(Values&: Urs, B: LastB);
1189 if (FirstUse != LastB->end())
1190 InsertAt = FirstUse;
1191 }
1192
1193 // Generate a new instruction for NA.
1194 Value *NewInst = fabricateGEP(NA, At: InsertAt, LocB: LastB);
1195
1196 // Convert all the children of Last node into roots, and append them
1197 // to the Roots list.
1198 if (LastCN > 0) {
1199 NodeVect &Cs = NCM[Last];
1200 for (GepNode *CN : Cs) {
1201 CN->Flags &= ~GepNode::Internal;
1202 CN->Flags |= GepNode::Root;
1203 CN->BaseVal = NewInst;
1204 Roots.push_back(x: CN);
1205 }
1206 }
1207
1208 // Lastly, if the Last node was used, replace all uses with the new GEP.
1209 // The uses reference the original GEP values.
1210 if (LastUsed) {
1211 NodeToUsesMap::iterator UF = Uses.find(x: Last);
1212 assert(UF != Uses.end() && "No use information found");
1213 UseSet &Us = UF->second;
1214 for (Use *U : Us)
1215 U->set(NewInst);
1216 }
1217 }
1218}
1219
1220void HexagonCommonGEP::removeDeadCode() {
1221 ValueVect BO;
1222 BO.push_back(x: &Fn->front());
1223
1224 for (unsigned i = 0; i < BO.size(); ++i) {
1225 BasicBlock *B = cast<BasicBlock>(Val: BO[i]);
1226 for (auto *DTN : children<DomTreeNode *>(G: DT->getNode(BB: B)))
1227 BO.push_back(x: DTN->getBlock());
1228 }
1229
1230 for (Value *V : llvm::reverse(C&: BO)) {
1231 BasicBlock *B = cast<BasicBlock>(Val: V);
1232 ValueVect Ins;
1233 for (Instruction &I : llvm::reverse(C&: *B))
1234 Ins.push_back(x: &I);
1235 for (Value *I : Ins) {
1236 Instruction *In = cast<Instruction>(Val: I);
1237 if (isInstructionTriviallyDead(I: In))
1238 In->eraseFromParent();
1239 }
1240 }
1241}
1242
1243bool HexagonCommonGEP::runOnFunction(Function &F) {
1244 if (skipFunction(F))
1245 return false;
1246
1247 // For now bail out on C++ exception handling.
1248 for (const BasicBlock &BB : F)
1249 for (const Instruction &I : BB)
1250 if (isa<InvokeInst>(Val: I) || isa<LandingPadInst>(Val: I))
1251 return false;
1252
1253 Fn = &F;
1254 DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
1255 PDT = &getAnalysis<PostDominatorTreeWrapperPass>().getPostDomTree();
1256 LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
1257 Ctx = &F.getContext();
1258
1259 Nodes.clear();
1260 Uses.clear();
1261 NodeOrder.clear();
1262
1263 SpecificBumpPtrAllocator<GepNode> Allocator;
1264 Mem = &Allocator;
1265
1266 collect();
1267 common();
1268
1269 NodeToValueMap Loc;
1270 computeNodePlacement(Loc);
1271 materialize(Loc);
1272 removeDeadCode();
1273
1274#ifdef EXPENSIVE_CHECKS
1275 // Run this only when expensive checks are enabled.
1276 if (verifyFunction(F, &dbgs()))
1277 report_fatal_error("Broken function");
1278#endif
1279 return true;
1280}
1281
1282namespace llvm {
1283
1284 FunctionPass *createHexagonCommonGEP() {
1285 return new HexagonCommonGEP();
1286 }
1287
1288} // end namespace llvm
1289