1 //===- BBVectorize.cpp - A Basic-Block Vectorizer -------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements a basic-block vectorization pass. The algorithm was
11 // inspired by that used by the Vienna MAP Vectorizor by Franchetti and Kral,
12 // et al. It works by looking for chains of pairable operations and then
13 // pairing them.
14 //
15 //===----------------------------------------------------------------------===//
16
17 #define BBV_NAME "bb-vectorize"
18 #include "llvm/Transforms/Vectorize.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/DenseSet.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallSet.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/Statistic.h"
25 #include "llvm/ADT/StringExtras.h"
26 #include "llvm/Analysis/AliasAnalysis.h"
27 #include "llvm/Analysis/AliasSetTracker.h"
28 #include "llvm/Analysis/GlobalsModRef.h"
29 #include "llvm/Analysis/ScalarEvolution.h"
30 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
31 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
32 #include "llvm/Analysis/TargetLibraryInfo.h"
33 #include "llvm/Analysis/TargetTransformInfo.h"
34 #include "llvm/Analysis/ValueTracking.h"
35 #include "llvm/IR/Constants.h"
36 #include "llvm/IR/DataLayout.h"
37 #include "llvm/IR/DerivedTypes.h"
38 #include "llvm/IR/Dominators.h"
39 #include "llvm/IR/Function.h"
40 #include "llvm/IR/Instructions.h"
41 #include "llvm/IR/IntrinsicInst.h"
42 #include "llvm/IR/Intrinsics.h"
43 #include "llvm/IR/LLVMContext.h"
44 #include "llvm/IR/Metadata.h"
45 #include "llvm/IR/Module.h"
46 #include "llvm/IR/Type.h"
47 #include "llvm/IR/ValueHandle.h"
48 #include "llvm/Pass.h"
49 #include "llvm/Support/CommandLine.h"
50 #include "llvm/Support/Debug.h"
51 #include "llvm/Support/raw_ostream.h"
52 #include "llvm/Transforms/Utils/Local.h"
53 #include <algorithm>
54 using namespace llvm;
55
56 #define DEBUG_TYPE BBV_NAME
57
58 static cl::opt<bool>
59 IgnoreTargetInfo("bb-vectorize-ignore-target-info", cl::init(false),
60 cl::Hidden, cl::desc("Ignore target information"));
61
62 static cl::opt<unsigned>
63 ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden,
64 cl::desc("The required chain depth for vectorization"));
65
66 static cl::opt<bool>
67 UseChainDepthWithTI("bb-vectorize-use-chain-depth", cl::init(false),
68 cl::Hidden, cl::desc("Use the chain depth requirement with"
69 " target information"));
70
71 static cl::opt<unsigned>
72 SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden,
73 cl::desc("The maximum search distance for instruction pairs"));
74
75 static cl::opt<bool>
76 SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden,
77 cl::desc("Replicating one element to a pair breaks the chain"));
78
79 static cl::opt<unsigned>
80 VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden,
81 cl::desc("The size of the native vector registers"));
82
83 static cl::opt<unsigned>
84 MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden,
85 cl::desc("The maximum number of pairing iterations"));
86
87 static cl::opt<bool>
88 Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden,
89 cl::desc("Don't try to form non-2^n-length vectors"));
90
91 static cl::opt<unsigned>
92 MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden,
93 cl::desc("The maximum number of pairable instructions per group"));
94
95 static cl::opt<unsigned>
96 MaxPairs("bb-vectorize-max-pairs-per-group", cl::init(3000), cl::Hidden,
97 cl::desc("The maximum number of candidate instruction pairs per group"));
98
99 static cl::opt<unsigned>
100 MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200),
101 cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use"
102 " a full cycle check"));
103
104 static cl::opt<bool>
105 NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden,
106 cl::desc("Don't try to vectorize boolean (i1) values"));
107
108 static cl::opt<bool>
109 NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden,
110 cl::desc("Don't try to vectorize integer values"));
111
112 static cl::opt<bool>
113 NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden,
114 cl::desc("Don't try to vectorize floating-point values"));
115
116 // FIXME: This should default to false once pointer vector support works.
117 static cl::opt<bool>
118 NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden,
119 cl::desc("Don't try to vectorize pointer values"));
120
121 static cl::opt<bool>
122 NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden,
123 cl::desc("Don't try to vectorize casting (conversion) operations"));
124
125 static cl::opt<bool>
126 NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden,
127 cl::desc("Don't try to vectorize floating-point math intrinsics"));
128
129 static cl::opt<bool>
130 NoBitManipulation("bb-vectorize-no-bitmanip", cl::init(false), cl::Hidden,
131 cl::desc("Don't try to vectorize BitManipulation intrinsics"));
132
133 static cl::opt<bool>
134 NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden,
135 cl::desc("Don't try to vectorize the fused-multiply-add intrinsic"));
136
137 static cl::opt<bool>
138 NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden,
139 cl::desc("Don't try to vectorize select instructions"));
140
141 static cl::opt<bool>
142 NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden,
143 cl::desc("Don't try to vectorize comparison instructions"));
144
145 static cl::opt<bool>
146 NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden,
147 cl::desc("Don't try to vectorize getelementptr instructions"));
148
149 static cl::opt<bool>
150 NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden,
151 cl::desc("Don't try to vectorize loads and stores"));
152
153 static cl::opt<bool>
154 AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden,
155 cl::desc("Only generate aligned loads and stores"));
156
157 static cl::opt<bool>
158 NoMemOpBoost("bb-vectorize-no-mem-op-boost",
159 cl::init(false), cl::Hidden,
160 cl::desc("Don't boost the chain-depth contribution of loads and stores"));
161
162 static cl::opt<bool>
163 FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden,
164 cl::desc("Use a fast instruction dependency analysis"));
165
166 #ifndef NDEBUG
167 static cl::opt<bool>
168 DebugInstructionExamination("bb-vectorize-debug-instruction-examination",
169 cl::init(false), cl::Hidden,
170 cl::desc("When debugging is enabled, output information on the"
171 " instruction-examination process"));
172 static cl::opt<bool>
173 DebugCandidateSelection("bb-vectorize-debug-candidate-selection",
174 cl::init(false), cl::Hidden,
175 cl::desc("When debugging is enabled, output information on the"
176 " candidate-selection process"));
177 static cl::opt<bool>
178 DebugPairSelection("bb-vectorize-debug-pair-selection",
179 cl::init(false), cl::Hidden,
180 cl::desc("When debugging is enabled, output information on the"
181 " pair-selection process"));
182 static cl::opt<bool>
183 DebugCycleCheck("bb-vectorize-debug-cycle-check",
184 cl::init(false), cl::Hidden,
185 cl::desc("When debugging is enabled, output information on the"
186 " cycle-checking process"));
187
188 static cl::opt<bool>
189 PrintAfterEveryPair("bb-vectorize-debug-print-after-every-pair",
190 cl::init(false), cl::Hidden,
191 cl::desc("When debugging is enabled, dump the basic block after"
192 " every pair is fused"));
193 #endif
194
195 STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize");
196
197 namespace {
198 struct BBVectorize : public BasicBlockPass {
199 static char ID; // Pass identification, replacement for typeid
200
201 const VectorizeConfig Config;
202
BBVectorize__anon0753cdc00111::BBVectorize203 BBVectorize(const VectorizeConfig &C = VectorizeConfig())
204 : BasicBlockPass(ID), Config(C) {
205 initializeBBVectorizePass(*PassRegistry::getPassRegistry());
206 }
207
BBVectorize__anon0753cdc00111::BBVectorize208 BBVectorize(Pass *P, Function &F, const VectorizeConfig &C)
209 : BasicBlockPass(ID), Config(C) {
210 AA = &P->getAnalysis<AAResultsWrapperPass>().getAAResults();
211 DT = &P->getAnalysis<DominatorTreeWrapperPass>().getDomTree();
212 SE = &P->getAnalysis<ScalarEvolutionWrapperPass>().getSE();
213 TLI = &P->getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
214 TTI = IgnoreTargetInfo
215 ? nullptr
216 : &P->getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
217 }
218
219 typedef std::pair<Value *, Value *> ValuePair;
220 typedef std::pair<ValuePair, int> ValuePairWithCost;
221 typedef std::pair<ValuePair, size_t> ValuePairWithDepth;
222 typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair
223 typedef std::pair<VPPair, unsigned> VPPairWithType;
224
225 AliasAnalysis *AA;
226 DominatorTree *DT;
227 ScalarEvolution *SE;
228 const TargetLibraryInfo *TLI;
229 const TargetTransformInfo *TTI;
230
231 // FIXME: const correct?
232
233 bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false);
234
235 bool getCandidatePairs(BasicBlock &BB,
236 BasicBlock::iterator &Start,
237 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
238 DenseSet<ValuePair> &FixedOrderPairs,
239 DenseMap<ValuePair, int> &CandidatePairCostSavings,
240 std::vector<Value *> &PairableInsts, bool NonPow2Len);
241
242 // FIXME: The current implementation does not account for pairs that
243 // are connected in multiple ways. For example:
244 // C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap)
245 enum PairConnectionType {
246 PairConnectionDirect,
247 PairConnectionSwap,
248 PairConnectionSplat
249 };
250
251 void computeConnectedPairs(
252 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
253 DenseSet<ValuePair> &CandidatePairsSet,
254 std::vector<Value *> &PairableInsts,
255 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
256 DenseMap<VPPair, unsigned> &PairConnectionTypes);
257
258 void buildDepMap(BasicBlock &BB,
259 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
260 std::vector<Value *> &PairableInsts,
261 DenseSet<ValuePair> &PairableInstUsers);
262
263 void choosePairs(DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
264 DenseSet<ValuePair> &CandidatePairsSet,
265 DenseMap<ValuePair, int> &CandidatePairCostSavings,
266 std::vector<Value *> &PairableInsts,
267 DenseSet<ValuePair> &FixedOrderPairs,
268 DenseMap<VPPair, unsigned> &PairConnectionTypes,
269 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
270 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
271 DenseSet<ValuePair> &PairableInstUsers,
272 DenseMap<Value *, Value *>& ChosenPairs);
273
274 void fuseChosenPairs(BasicBlock &BB,
275 std::vector<Value *> &PairableInsts,
276 DenseMap<Value *, Value *>& ChosenPairs,
277 DenseSet<ValuePair> &FixedOrderPairs,
278 DenseMap<VPPair, unsigned> &PairConnectionTypes,
279 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
280 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps);
281
282
283 bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore);
284
285 bool areInstsCompatible(Instruction *I, Instruction *J,
286 bool IsSimpleLoadStore, bool NonPow2Len,
287 int &CostSavings, int &FixedOrder);
288
289 bool trackUsesOfI(DenseSet<Value *> &Users,
290 AliasSetTracker &WriteSet, Instruction *I,
291 Instruction *J, bool UpdateUsers = true,
292 DenseSet<ValuePair> *LoadMoveSetPairs = nullptr);
293
294 void computePairsConnectedTo(
295 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
296 DenseSet<ValuePair> &CandidatePairsSet,
297 std::vector<Value *> &PairableInsts,
298 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
299 DenseMap<VPPair, unsigned> &PairConnectionTypes,
300 ValuePair P);
301
302 bool pairsConflict(ValuePair P, ValuePair Q,
303 DenseSet<ValuePair> &PairableInstUsers,
304 DenseMap<ValuePair, std::vector<ValuePair> >
305 *PairableInstUserMap = nullptr,
306 DenseSet<VPPair> *PairableInstUserPairSet = nullptr);
307
308 bool pairWillFormCycle(ValuePair P,
309 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUsers,
310 DenseSet<ValuePair> &CurrentPairs);
311
312 void pruneDAGFor(
313 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
314 std::vector<Value *> &PairableInsts,
315 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
316 DenseSet<ValuePair> &PairableInstUsers,
317 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
318 DenseSet<VPPair> &PairableInstUserPairSet,
319 DenseMap<Value *, Value *> &ChosenPairs,
320 DenseMap<ValuePair, size_t> &DAG,
321 DenseSet<ValuePair> &PrunedDAG, ValuePair J,
322 bool UseCycleCheck);
323
324 void buildInitialDAGFor(
325 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
326 DenseSet<ValuePair> &CandidatePairsSet,
327 std::vector<Value *> &PairableInsts,
328 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
329 DenseSet<ValuePair> &PairableInstUsers,
330 DenseMap<Value *, Value *> &ChosenPairs,
331 DenseMap<ValuePair, size_t> &DAG, ValuePair J);
332
333 void findBestDAGFor(
334 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
335 DenseSet<ValuePair> &CandidatePairsSet,
336 DenseMap<ValuePair, int> &CandidatePairCostSavings,
337 std::vector<Value *> &PairableInsts,
338 DenseSet<ValuePair> &FixedOrderPairs,
339 DenseMap<VPPair, unsigned> &PairConnectionTypes,
340 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
341 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
342 DenseSet<ValuePair> &PairableInstUsers,
343 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
344 DenseSet<VPPair> &PairableInstUserPairSet,
345 DenseMap<Value *, Value *> &ChosenPairs,
346 DenseSet<ValuePair> &BestDAG, size_t &BestMaxDepth,
347 int &BestEffSize, Value *II, std::vector<Value *>&JJ,
348 bool UseCycleCheck);
349
350 Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
351 Instruction *J, unsigned o);
352
353 void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
354 unsigned MaskOffset, unsigned NumInElem,
355 unsigned NumInElem1, unsigned IdxOffset,
356 std::vector<Constant*> &Mask);
357
358 Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I,
359 Instruction *J);
360
361 bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J,
362 unsigned o, Value *&LOp, unsigned numElemL,
363 Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ,
364 unsigned IdxOff = 0);
365
366 Value *getReplacementInput(LLVMContext& Context, Instruction *I,
367 Instruction *J, unsigned o, bool IBeforeJ);
368
369 void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
370 Instruction *J, SmallVectorImpl<Value *> &ReplacedOperands,
371 bool IBeforeJ);
372
373 void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
374 Instruction *J, Instruction *K,
375 Instruction *&InsertionPt, Instruction *&K1,
376 Instruction *&K2);
377
378 void collectPairLoadMoveSet(BasicBlock &BB,
379 DenseMap<Value *, Value *> &ChosenPairs,
380 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
381 DenseSet<ValuePair> &LoadMoveSetPairs,
382 Instruction *I);
383
384 void collectLoadMoveSet(BasicBlock &BB,
385 std::vector<Value *> &PairableInsts,
386 DenseMap<Value *, Value *> &ChosenPairs,
387 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
388 DenseSet<ValuePair> &LoadMoveSetPairs);
389
390 bool canMoveUsesOfIAfterJ(BasicBlock &BB,
391 DenseSet<ValuePair> &LoadMoveSetPairs,
392 Instruction *I, Instruction *J);
393
394 void moveUsesOfIAfterJ(BasicBlock &BB,
395 DenseSet<ValuePair> &LoadMoveSetPairs,
396 Instruction *&InsertionPt,
397 Instruction *I, Instruction *J);
398
vectorizeBB__anon0753cdc00111::BBVectorize399 bool vectorizeBB(BasicBlock &BB) {
400 if (skipBasicBlock(BB))
401 return false;
402 if (!DT->isReachableFromEntry(&BB)) {
403 DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() <<
404 " in " << BB.getParent()->getName() << "\n");
405 return false;
406 }
407
408 DEBUG(if (TTI) dbgs() << "BBV: using target information\n");
409
410 bool changed = false;
411 // Iterate a sufficient number of times to merge types of size 1 bit,
412 // then 2 bits, then 4, etc. up to half of the target vector width of the
413 // target vector register.
414 unsigned n = 1;
415 for (unsigned v = 2;
416 (TTI || v <= Config.VectorBits) &&
417 (!Config.MaxIter || n <= Config.MaxIter);
418 v *= 2, ++n) {
419 DEBUG(dbgs() << "BBV: fusing loop #" << n <<
420 " for " << BB.getName() << " in " <<
421 BB.getParent()->getName() << "...\n");
422 if (vectorizePairs(BB))
423 changed = true;
424 else
425 break;
426 }
427
428 if (changed && !Pow2LenOnly) {
429 ++n;
430 for (; !Config.MaxIter || n <= Config.MaxIter; ++n) {
431 DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " <<
432 n << " for " << BB.getName() << " in " <<
433 BB.getParent()->getName() << "...\n");
434 if (!vectorizePairs(BB, true)) break;
435 }
436 }
437
438 DEBUG(dbgs() << "BBV: done!\n");
439 return changed;
440 }
441
runOnBasicBlock__anon0753cdc00111::BBVectorize442 bool runOnBasicBlock(BasicBlock &BB) override {
443 // OptimizeNone check deferred to vectorizeBB().
444
445 AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
446 DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
447 SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
448 TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
449 TTI = IgnoreTargetInfo
450 ? nullptr
451 : &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(
452 *BB.getParent());
453
454 return vectorizeBB(BB);
455 }
456
getAnalysisUsage__anon0753cdc00111::BBVectorize457 void getAnalysisUsage(AnalysisUsage &AU) const override {
458 BasicBlockPass::getAnalysisUsage(AU);
459 AU.addRequired<AAResultsWrapperPass>();
460 AU.addRequired<DominatorTreeWrapperPass>();
461 AU.addRequired<ScalarEvolutionWrapperPass>();
462 AU.addRequired<TargetLibraryInfoWrapperPass>();
463 AU.addRequired<TargetTransformInfoWrapperPass>();
464 AU.addPreserved<DominatorTreeWrapperPass>();
465 AU.addPreserved<GlobalsAAWrapperPass>();
466 AU.addPreserved<ScalarEvolutionWrapperPass>();
467 AU.addPreserved<SCEVAAWrapperPass>();
468 AU.setPreservesCFG();
469 }
470
getVecTypeForPair__anon0753cdc00111::BBVectorize471 static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) {
472 assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() &&
473 "Cannot form vector from incompatible scalar types");
474 Type *STy = ElemTy->getScalarType();
475
476 unsigned numElem;
477 if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) {
478 numElem = VTy->getNumElements();
479 } else {
480 numElem = 1;
481 }
482
483 if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) {
484 numElem += VTy->getNumElements();
485 } else {
486 numElem += 1;
487 }
488
489 return VectorType::get(STy, numElem);
490 }
491
getInstructionTypes__anon0753cdc00111::BBVectorize492 static inline void getInstructionTypes(Instruction *I,
493 Type *&T1, Type *&T2) {
494 if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
495 // For stores, it is the value type, not the pointer type that matters
496 // because the value is what will come from a vector register.
497
498 Value *IVal = SI->getValueOperand();
499 T1 = IVal->getType();
500 } else {
501 T1 = I->getType();
502 }
503
504 if (CastInst *CI = dyn_cast<CastInst>(I))
505 T2 = CI->getSrcTy();
506 else
507 T2 = T1;
508
509 if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
510 T2 = SI->getCondition()->getType();
511 } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) {
512 T2 = SI->getOperand(0)->getType();
513 } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
514 T2 = CI->getOperand(0)->getType();
515 }
516 }
517
518 // Returns the weight associated with the provided value. A chain of
519 // candidate pairs has a length given by the sum of the weights of its
520 // members (one weight per pair; the weight of each member of the pair
521 // is assumed to be the same). This length is then compared to the
522 // chain-length threshold to determine if a given chain is significant
523 // enough to be vectorized. The length is also used in comparing
524 // candidate chains where longer chains are considered to be better.
525 // Note: when this function returns 0, the resulting instructions are
526 // not actually fused.
getDepthFactor__anon0753cdc00111::BBVectorize527 inline size_t getDepthFactor(Value *V) {
528 // InsertElement and ExtractElement have a depth factor of zero. This is
529 // for two reasons: First, they cannot be usefully fused. Second, because
530 // the pass generates a lot of these, they can confuse the simple metric
531 // used to compare the dags in the next iteration. Thus, giving them a
532 // weight of zero allows the pass to essentially ignore them in
533 // subsequent iterations when looking for vectorization opportunities
534 // while still tracking dependency chains that flow through those
535 // instructions.
536 if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V))
537 return 0;
538
539 // Give a load or store half of the required depth so that load/store
540 // pairs will vectorize.
541 if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V)))
542 return Config.ReqChainDepth/2;
543
544 return 1;
545 }
546
547 // Returns the cost of the provided instruction using TTI.
548 // This does not handle loads and stores.
getInstrCost__anon0753cdc00111::BBVectorize549 unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2,
550 TargetTransformInfo::OperandValueKind Op1VK =
551 TargetTransformInfo::OK_AnyValue,
552 TargetTransformInfo::OperandValueKind Op2VK =
553 TargetTransformInfo::OK_AnyValue) {
554 switch (Opcode) {
555 default: break;
556 case Instruction::GetElementPtr:
557 // We mark this instruction as zero-cost because scalar GEPs are usually
558 // lowered to the instruction addressing mode. At the moment we don't
559 // generate vector GEPs.
560 return 0;
561 case Instruction::Br:
562 return TTI->getCFInstrCost(Opcode);
563 case Instruction::PHI:
564 return 0;
565 case Instruction::Add:
566 case Instruction::FAdd:
567 case Instruction::Sub:
568 case Instruction::FSub:
569 case Instruction::Mul:
570 case Instruction::FMul:
571 case Instruction::UDiv:
572 case Instruction::SDiv:
573 case Instruction::FDiv:
574 case Instruction::URem:
575 case Instruction::SRem:
576 case Instruction::FRem:
577 case Instruction::Shl:
578 case Instruction::LShr:
579 case Instruction::AShr:
580 case Instruction::And:
581 case Instruction::Or:
582 case Instruction::Xor:
583 return TTI->getArithmeticInstrCost(Opcode, T1, Op1VK, Op2VK);
584 case Instruction::Select:
585 case Instruction::ICmp:
586 case Instruction::FCmp:
587 return TTI->getCmpSelInstrCost(Opcode, T1, T2);
588 case Instruction::ZExt:
589 case Instruction::SExt:
590 case Instruction::FPToUI:
591 case Instruction::FPToSI:
592 case Instruction::FPExt:
593 case Instruction::PtrToInt:
594 case Instruction::IntToPtr:
595 case Instruction::SIToFP:
596 case Instruction::UIToFP:
597 case Instruction::Trunc:
598 case Instruction::FPTrunc:
599 case Instruction::BitCast:
600 case Instruction::ShuffleVector:
601 return TTI->getCastInstrCost(Opcode, T1, T2);
602 }
603
604 return 1;
605 }
606
607 // This determines the relative offset of two loads or stores, returning
608 // true if the offset could be determined to be some constant value.
609 // For example, if OffsetInElmts == 1, then J accesses the memory directly
610 // after I; if OffsetInElmts == -1 then I accesses the memory
611 // directly after J.
getPairPtrInfo__anon0753cdc00111::BBVectorize612 bool getPairPtrInfo(Instruction *I, Instruction *J,
613 Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment,
614 unsigned &IAddressSpace, unsigned &JAddressSpace,
615 int64_t &OffsetInElmts, bool ComputeOffset = true) {
616 OffsetInElmts = 0;
617 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
618 LoadInst *LJ = cast<LoadInst>(J);
619 IPtr = LI->getPointerOperand();
620 JPtr = LJ->getPointerOperand();
621 IAlignment = LI->getAlignment();
622 JAlignment = LJ->getAlignment();
623 IAddressSpace = LI->getPointerAddressSpace();
624 JAddressSpace = LJ->getPointerAddressSpace();
625 } else {
626 StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J);
627 IPtr = SI->getPointerOperand();
628 JPtr = SJ->getPointerOperand();
629 IAlignment = SI->getAlignment();
630 JAlignment = SJ->getAlignment();
631 IAddressSpace = SI->getPointerAddressSpace();
632 JAddressSpace = SJ->getPointerAddressSpace();
633 }
634
635 if (!ComputeOffset)
636 return true;
637
638 const SCEV *IPtrSCEV = SE->getSCEV(IPtr);
639 const SCEV *JPtrSCEV = SE->getSCEV(JPtr);
640
641 // If this is a trivial offset, then we'll get something like
642 // 1*sizeof(type). With target data, which we need anyway, this will get
643 // constant folded into a number.
644 const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV);
645 if (const SCEVConstant *ConstOffSCEV =
646 dyn_cast<SCEVConstant>(OffsetSCEV)) {
647 ConstantInt *IntOff = ConstOffSCEV->getValue();
648 int64_t Offset = IntOff->getSExtValue();
649 const DataLayout &DL = I->getModule()->getDataLayout();
650 Type *VTy = IPtr->getType()->getPointerElementType();
651 int64_t VTyTSS = (int64_t)DL.getTypeStoreSize(VTy);
652
653 Type *VTy2 = JPtr->getType()->getPointerElementType();
654 if (VTy != VTy2 && Offset < 0) {
655 int64_t VTy2TSS = (int64_t)DL.getTypeStoreSize(VTy2);
656 OffsetInElmts = Offset/VTy2TSS;
657 return (std::abs(Offset) % VTy2TSS) == 0;
658 }
659
660 OffsetInElmts = Offset/VTyTSS;
661 return (std::abs(Offset) % VTyTSS) == 0;
662 }
663
664 return false;
665 }
666
667 // Returns true if the provided CallInst represents an intrinsic that can
668 // be vectorized.
isVectorizableIntrinsic__anon0753cdc00111::BBVectorize669 bool isVectorizableIntrinsic(CallInst* I) {
670 Function *F = I->getCalledFunction();
671 if (!F) return false;
672
673 Intrinsic::ID IID = F->getIntrinsicID();
674 if (!IID) return false;
675
676 switch(IID) {
677 default:
678 return false;
679 case Intrinsic::sqrt:
680 case Intrinsic::powi:
681 case Intrinsic::sin:
682 case Intrinsic::cos:
683 case Intrinsic::log:
684 case Intrinsic::log2:
685 case Intrinsic::log10:
686 case Intrinsic::exp:
687 case Intrinsic::exp2:
688 case Intrinsic::pow:
689 case Intrinsic::round:
690 case Intrinsic::copysign:
691 case Intrinsic::ceil:
692 case Intrinsic::nearbyint:
693 case Intrinsic::rint:
694 case Intrinsic::trunc:
695 case Intrinsic::floor:
696 case Intrinsic::fabs:
697 case Intrinsic::minnum:
698 case Intrinsic::maxnum:
699 return Config.VectorizeMath;
700 case Intrinsic::bswap:
701 case Intrinsic::ctpop:
702 case Intrinsic::ctlz:
703 case Intrinsic::cttz:
704 return Config.VectorizeBitManipulations;
705 case Intrinsic::fma:
706 case Intrinsic::fmuladd:
707 return Config.VectorizeFMA;
708 }
709 }
710
isPureIEChain__anon0753cdc00111::BBVectorize711 bool isPureIEChain(InsertElementInst *IE) {
712 InsertElementInst *IENext = IE;
713 do {
714 if (!isa<UndefValue>(IENext->getOperand(0)) &&
715 !isa<InsertElementInst>(IENext->getOperand(0))) {
716 return false;
717 }
718 } while ((IENext =
719 dyn_cast<InsertElementInst>(IENext->getOperand(0))));
720
721 return true;
722 }
723 };
724
725 // This function implements one vectorization iteration on the provided
726 // basic block. It returns true if the block is changed.
vectorizePairs(BasicBlock & BB,bool NonPow2Len)727 bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) {
728 bool ShouldContinue;
729 BasicBlock::iterator Start = BB.getFirstInsertionPt();
730
731 std::vector<Value *> AllPairableInsts;
732 DenseMap<Value *, Value *> AllChosenPairs;
733 DenseSet<ValuePair> AllFixedOrderPairs;
734 DenseMap<VPPair, unsigned> AllPairConnectionTypes;
735 DenseMap<ValuePair, std::vector<ValuePair> > AllConnectedPairs,
736 AllConnectedPairDeps;
737
738 do {
739 std::vector<Value *> PairableInsts;
740 DenseMap<Value *, std::vector<Value *> > CandidatePairs;
741 DenseSet<ValuePair> FixedOrderPairs;
742 DenseMap<ValuePair, int> CandidatePairCostSavings;
743 ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs,
744 FixedOrderPairs,
745 CandidatePairCostSavings,
746 PairableInsts, NonPow2Len);
747 if (PairableInsts.empty()) continue;
748
749 // Build the candidate pair set for faster lookups.
750 DenseSet<ValuePair> CandidatePairsSet;
751 for (DenseMap<Value *, std::vector<Value *> >::iterator I =
752 CandidatePairs.begin(), E = CandidatePairs.end(); I != E; ++I)
753 for (std::vector<Value *>::iterator J = I->second.begin(),
754 JE = I->second.end(); J != JE; ++J)
755 CandidatePairsSet.insert(ValuePair(I->first, *J));
756
757 // Now we have a map of all of the pairable instructions and we need to
758 // select the best possible pairing. A good pairing is one such that the
759 // users of the pair are also paired. This defines a (directed) forest
760 // over the pairs such that two pairs are connected iff the second pair
761 // uses the first.
762
763 // Note that it only matters that both members of the second pair use some
764 // element of the first pair (to allow for splatting).
765
766 DenseMap<ValuePair, std::vector<ValuePair> > ConnectedPairs,
767 ConnectedPairDeps;
768 DenseMap<VPPair, unsigned> PairConnectionTypes;
769 computeConnectedPairs(CandidatePairs, CandidatePairsSet,
770 PairableInsts, ConnectedPairs, PairConnectionTypes);
771 if (ConnectedPairs.empty()) continue;
772
773 for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator
774 I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
775 I != IE; ++I)
776 for (std::vector<ValuePair>::iterator J = I->second.begin(),
777 JE = I->second.end(); J != JE; ++J)
778 ConnectedPairDeps[*J].push_back(I->first);
779
780 // Build the pairable-instruction dependency map
781 DenseSet<ValuePair> PairableInstUsers;
782 buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers);
783
784 // There is now a graph of the connected pairs. For each variable, pick
785 // the pairing with the largest dag meeting the depth requirement on at
786 // least one branch. Then select all pairings that are part of that dag
787 // and remove them from the list of available pairings and pairable
788 // variables.
789
790 DenseMap<Value *, Value *> ChosenPairs;
791 choosePairs(CandidatePairs, CandidatePairsSet,
792 CandidatePairCostSavings,
793 PairableInsts, FixedOrderPairs, PairConnectionTypes,
794 ConnectedPairs, ConnectedPairDeps,
795 PairableInstUsers, ChosenPairs);
796
797 if (ChosenPairs.empty()) continue;
798 AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(),
799 PairableInsts.end());
800 AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end());
801
802 // Only for the chosen pairs, propagate information on fixed-order pairs,
803 // pair connections, and their types to the data structures used by the
804 // pair fusion procedures.
805 for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(),
806 IE = ChosenPairs.end(); I != IE; ++I) {
807 if (FixedOrderPairs.count(*I))
808 AllFixedOrderPairs.insert(*I);
809 else if (FixedOrderPairs.count(ValuePair(I->second, I->first)))
810 AllFixedOrderPairs.insert(ValuePair(I->second, I->first));
811
812 for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin();
813 J != IE; ++J) {
814 DenseMap<VPPair, unsigned>::iterator K =
815 PairConnectionTypes.find(VPPair(*I, *J));
816 if (K != PairConnectionTypes.end()) {
817 AllPairConnectionTypes.insert(*K);
818 } else {
819 K = PairConnectionTypes.find(VPPair(*J, *I));
820 if (K != PairConnectionTypes.end())
821 AllPairConnectionTypes.insert(*K);
822 }
823 }
824 }
825
826 for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator
827 I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
828 I != IE; ++I)
829 for (std::vector<ValuePair>::iterator J = I->second.begin(),
830 JE = I->second.end(); J != JE; ++J)
831 if (AllPairConnectionTypes.count(VPPair(I->first, *J))) {
832 AllConnectedPairs[I->first].push_back(*J);
833 AllConnectedPairDeps[*J].push_back(I->first);
834 }
835 } while (ShouldContinue);
836
837 if (AllChosenPairs.empty()) return false;
838 NumFusedOps += AllChosenPairs.size();
839
840 // A set of pairs has now been selected. It is now necessary to replace the
841 // paired instructions with vector instructions. For this procedure each
842 // operand must be replaced with a vector operand. This vector is formed
843 // by using build_vector on the old operands. The replaced values are then
844 // replaced with a vector_extract on the result. Subsequent optimization
845 // passes should coalesce the build/extract combinations.
846
847 fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs,
848 AllPairConnectionTypes,
849 AllConnectedPairs, AllConnectedPairDeps);
850
851 // It is important to cleanup here so that future iterations of this
852 // function have less work to do.
853 (void)SimplifyInstructionsInBlock(&BB, TLI);
854 return true;
855 }
856
857 // This function returns true if the provided instruction is capable of being
858 // fused into a vector instruction. This determination is based only on the
859 // type and other attributes of the instruction.
isInstVectorizable(Instruction * I,bool & IsSimpleLoadStore)860 bool BBVectorize::isInstVectorizable(Instruction *I,
861 bool &IsSimpleLoadStore) {
862 IsSimpleLoadStore = false;
863
864 if (CallInst *C = dyn_cast<CallInst>(I)) {
865 if (!isVectorizableIntrinsic(C))
866 return false;
867 } else if (LoadInst *L = dyn_cast<LoadInst>(I)) {
868 // Vectorize simple loads if possbile:
869 IsSimpleLoadStore = L->isSimple();
870 if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
871 return false;
872 } else if (StoreInst *S = dyn_cast<StoreInst>(I)) {
873 // Vectorize simple stores if possbile:
874 IsSimpleLoadStore = S->isSimple();
875 if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
876 return false;
877 } else if (CastInst *C = dyn_cast<CastInst>(I)) {
878 // We can vectorize casts, but not casts of pointer types, etc.
879 if (!Config.VectorizeCasts)
880 return false;
881
882 Type *SrcTy = C->getSrcTy();
883 if (!SrcTy->isSingleValueType())
884 return false;
885
886 Type *DestTy = C->getDestTy();
887 if (!DestTy->isSingleValueType())
888 return false;
889 } else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
890 if (!Config.VectorizeSelect)
891 return false;
892 // We can vectorize a select if either all operands are scalars,
893 // or all operands are vectors. Trying to "widen" a select between
894 // vectors that has a scalar condition results in a malformed select.
895 // FIXME: We could probably be smarter about this by rewriting the select
896 // with different types instead.
897 return (SI->getCondition()->getType()->isVectorTy() ==
898 SI->getTrueValue()->getType()->isVectorTy());
899 } else if (isa<CmpInst>(I)) {
900 if (!Config.VectorizeCmp)
901 return false;
902 } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) {
903 if (!Config.VectorizeGEP)
904 return false;
905
906 // Currently, vector GEPs exist only with one index.
907 if (G->getNumIndices() != 1)
908 return false;
909 } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) ||
910 isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) {
911 return false;
912 }
913
914 Type *T1, *T2;
915 getInstructionTypes(I, T1, T2);
916
917 // Not every type can be vectorized...
918 if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
919 !(VectorType::isValidElementType(T2) || T2->isVectorTy()))
920 return false;
921
922 if (T1->getScalarSizeInBits() == 1) {
923 if (!Config.VectorizeBools)
924 return false;
925 } else {
926 if (!Config.VectorizeInts && T1->isIntOrIntVectorTy())
927 return false;
928 }
929
930 if (T2->getScalarSizeInBits() == 1) {
931 if (!Config.VectorizeBools)
932 return false;
933 } else {
934 if (!Config.VectorizeInts && T2->isIntOrIntVectorTy())
935 return false;
936 }
937
938 if (!Config.VectorizeFloats
939 && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
940 return false;
941
942 // Don't vectorize target-specific types.
943 if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy())
944 return false;
945 if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy())
946 return false;
947
948 if (!Config.VectorizePointers && (T1->getScalarType()->isPointerTy() ||
949 T2->getScalarType()->isPointerTy()))
950 return false;
951
952 if (!TTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits ||
953 T2->getPrimitiveSizeInBits() >= Config.VectorBits))
954 return false;
955
956 return true;
957 }
958
959 // This function returns true if the two provided instructions are compatible
960 // (meaning that they can be fused into a vector instruction). This assumes
961 // that I has already been determined to be vectorizable and that J is not
962 // in the use dag of I.
areInstsCompatible(Instruction * I,Instruction * J,bool IsSimpleLoadStore,bool NonPow2Len,int & CostSavings,int & FixedOrder)963 bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J,
964 bool IsSimpleLoadStore, bool NonPow2Len,
965 int &CostSavings, int &FixedOrder) {
966 DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I <<
967 " <-> " << *J << "\n");
968
969 CostSavings = 0;
970 FixedOrder = 0;
971
972 // Loads and stores can be merged if they have different alignments,
973 // but are otherwise the same.
974 if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment |
975 (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0)))
976 return false;
977
978 Type *IT1, *IT2, *JT1, *JT2;
979 getInstructionTypes(I, IT1, IT2);
980 getInstructionTypes(J, JT1, JT2);
981 unsigned MaxTypeBits = std::max(
982 IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(),
983 IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits());
984 if (!TTI && MaxTypeBits > Config.VectorBits)
985 return false;
986
987 // FIXME: handle addsub-type operations!
988
989 if (IsSimpleLoadStore) {
990 Value *IPtr, *JPtr;
991 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
992 int64_t OffsetInElmts = 0;
993 if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
994 IAddressSpace, JAddressSpace, OffsetInElmts) &&
995 std::abs(OffsetInElmts) == 1) {
996 FixedOrder = (int) OffsetInElmts;
997 unsigned BottomAlignment = IAlignment;
998 if (OffsetInElmts < 0) BottomAlignment = JAlignment;
999
1000 Type *aTypeI = isa<StoreInst>(I) ?
1001 cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
1002 Type *aTypeJ = isa<StoreInst>(J) ?
1003 cast<StoreInst>(J)->getValueOperand()->getType() : J->getType();
1004 Type *VType = getVecTypeForPair(aTypeI, aTypeJ);
1005
1006 if (Config.AlignedOnly) {
1007 // An aligned load or store is possible only if the instruction
1008 // with the lower offset has an alignment suitable for the
1009 // vector type.
1010 const DataLayout &DL = I->getModule()->getDataLayout();
1011 unsigned VecAlignment = DL.getPrefTypeAlignment(VType);
1012 if (BottomAlignment < VecAlignment)
1013 return false;
1014 }
1015
1016 if (TTI) {
1017 unsigned ICost = TTI->getMemoryOpCost(I->getOpcode(), aTypeI,
1018 IAlignment, IAddressSpace);
1019 unsigned JCost = TTI->getMemoryOpCost(J->getOpcode(), aTypeJ,
1020 JAlignment, JAddressSpace);
1021 unsigned VCost = TTI->getMemoryOpCost(I->getOpcode(), VType,
1022 BottomAlignment,
1023 IAddressSpace);
1024
1025 ICost += TTI->getAddressComputationCost(aTypeI);
1026 JCost += TTI->getAddressComputationCost(aTypeJ);
1027 VCost += TTI->getAddressComputationCost(VType);
1028
1029 if (VCost > ICost + JCost)
1030 return false;
1031
1032 // We don't want to fuse to a type that will be split, even
1033 // if the two input types will also be split and there is no other
1034 // associated cost.
1035 unsigned VParts = TTI->getNumberOfParts(VType);
1036 if (VParts > 1)
1037 return false;
1038 else if (!VParts && VCost == ICost + JCost)
1039 return false;
1040
1041 CostSavings = ICost + JCost - VCost;
1042 }
1043 } else {
1044 return false;
1045 }
1046 } else if (TTI) {
1047 unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2);
1048 unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2);
1049 Type *VT1 = getVecTypeForPair(IT1, JT1),
1050 *VT2 = getVecTypeForPair(IT2, JT2);
1051 TargetTransformInfo::OperandValueKind Op1VK =
1052 TargetTransformInfo::OK_AnyValue;
1053 TargetTransformInfo::OperandValueKind Op2VK =
1054 TargetTransformInfo::OK_AnyValue;
1055
1056 // On some targets (example X86) the cost of a vector shift may vary
1057 // depending on whether the second operand is a Uniform or
1058 // NonUniform Constant.
1059 switch (I->getOpcode()) {
1060 default : break;
1061 case Instruction::Shl:
1062 case Instruction::LShr:
1063 case Instruction::AShr:
1064
1065 // If both I and J are scalar shifts by constant, then the
1066 // merged vector shift count would be either a constant splat value
1067 // or a non-uniform vector of constants.
1068 if (ConstantInt *CII = dyn_cast<ConstantInt>(I->getOperand(1))) {
1069 if (ConstantInt *CIJ = dyn_cast<ConstantInt>(J->getOperand(1)))
1070 Op2VK = CII == CIJ ? TargetTransformInfo::OK_UniformConstantValue :
1071 TargetTransformInfo::OK_NonUniformConstantValue;
1072 } else {
1073 // Check for a splat of a constant or for a non uniform vector
1074 // of constants.
1075 Value *IOp = I->getOperand(1);
1076 Value *JOp = J->getOperand(1);
1077 if ((isa<ConstantVector>(IOp) || isa<ConstantDataVector>(IOp)) &&
1078 (isa<ConstantVector>(JOp) || isa<ConstantDataVector>(JOp))) {
1079 Op2VK = TargetTransformInfo::OK_NonUniformConstantValue;
1080 Constant *SplatValue = cast<Constant>(IOp)->getSplatValue();
1081 if (SplatValue != nullptr &&
1082 SplatValue == cast<Constant>(JOp)->getSplatValue())
1083 Op2VK = TargetTransformInfo::OK_UniformConstantValue;
1084 }
1085 }
1086 }
1087
1088 // Note that this procedure is incorrect for insert and extract element
1089 // instructions (because combining these often results in a shuffle),
1090 // but this cost is ignored (because insert and extract element
1091 // instructions are assigned a zero depth factor and are not really
1092 // fused in general).
1093 unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2, Op1VK, Op2VK);
1094
1095 if (VCost > ICost + JCost)
1096 return false;
1097
1098 // We don't want to fuse to a type that will be split, even
1099 // if the two input types will also be split and there is no other
1100 // associated cost.
1101 unsigned VParts1 = TTI->getNumberOfParts(VT1),
1102 VParts2 = TTI->getNumberOfParts(VT2);
1103 if (VParts1 > 1 || VParts2 > 1)
1104 return false;
1105 else if ((!VParts1 || !VParts2) && VCost == ICost + JCost)
1106 return false;
1107
1108 CostSavings = ICost + JCost - VCost;
1109 }
1110
1111 // The powi,ctlz,cttz intrinsics are special because only the first
1112 // argument is vectorized, the second arguments must be equal.
1113 CallInst *CI = dyn_cast<CallInst>(I);
1114 Function *FI;
1115 if (CI && (FI = CI->getCalledFunction())) {
1116 Intrinsic::ID IID = FI->getIntrinsicID();
1117 if (IID == Intrinsic::powi || IID == Intrinsic::ctlz ||
1118 IID == Intrinsic::cttz) {
1119 Value *A1I = CI->getArgOperand(1),
1120 *A1J = cast<CallInst>(J)->getArgOperand(1);
1121 const SCEV *A1ISCEV = SE->getSCEV(A1I),
1122 *A1JSCEV = SE->getSCEV(A1J);
1123 return (A1ISCEV == A1JSCEV);
1124 }
1125
1126 if (IID && TTI) {
1127 FastMathFlags FMFCI;
1128 if (auto *FPMOCI = dyn_cast<FPMathOperator>(CI))
1129 FMFCI = FPMOCI->getFastMathFlags();
1130
1131 SmallVector<Type*, 4> Tys;
1132 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i)
1133 Tys.push_back(CI->getArgOperand(i)->getType());
1134 unsigned ICost = TTI->getIntrinsicInstrCost(IID, IT1, Tys, FMFCI);
1135
1136 Tys.clear();
1137 CallInst *CJ = cast<CallInst>(J);
1138
1139 FastMathFlags FMFCJ;
1140 if (auto *FPMOCJ = dyn_cast<FPMathOperator>(CJ))
1141 FMFCJ = FPMOCJ->getFastMathFlags();
1142
1143 for (unsigned i = 0, ie = CJ->getNumArgOperands(); i != ie; ++i)
1144 Tys.push_back(CJ->getArgOperand(i)->getType());
1145 unsigned JCost = TTI->getIntrinsicInstrCost(IID, JT1, Tys, FMFCJ);
1146
1147 Tys.clear();
1148 assert(CI->getNumArgOperands() == CJ->getNumArgOperands() &&
1149 "Intrinsic argument counts differ");
1150 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
1151 if ((IID == Intrinsic::powi || IID == Intrinsic::ctlz ||
1152 IID == Intrinsic::cttz) && i == 1)
1153 Tys.push_back(CI->getArgOperand(i)->getType());
1154 else
1155 Tys.push_back(getVecTypeForPair(CI->getArgOperand(i)->getType(),
1156 CJ->getArgOperand(i)->getType()));
1157 }
1158
1159 FastMathFlags FMFV = FMFCI;
1160 FMFV &= FMFCJ;
1161 Type *RetTy = getVecTypeForPair(IT1, JT1);
1162 unsigned VCost = TTI->getIntrinsicInstrCost(IID, RetTy, Tys, FMFV);
1163
1164 if (VCost > ICost + JCost)
1165 return false;
1166
1167 // We don't want to fuse to a type that will be split, even
1168 // if the two input types will also be split and there is no other
1169 // associated cost.
1170 unsigned RetParts = TTI->getNumberOfParts(RetTy);
1171 if (RetParts > 1)
1172 return false;
1173 else if (!RetParts && VCost == ICost + JCost)
1174 return false;
1175
1176 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
1177 if (!Tys[i]->isVectorTy())
1178 continue;
1179
1180 unsigned NumParts = TTI->getNumberOfParts(Tys[i]);
1181 if (NumParts > 1)
1182 return false;
1183 else if (!NumParts && VCost == ICost + JCost)
1184 return false;
1185 }
1186
1187 CostSavings = ICost + JCost - VCost;
1188 }
1189 }
1190
1191 return true;
1192 }
1193
1194 // Figure out whether or not J uses I and update the users and write-set
1195 // structures associated with I. Specifically, Users represents the set of
1196 // instructions that depend on I. WriteSet represents the set
1197 // of memory locations that are dependent on I. If UpdateUsers is true,
1198 // and J uses I, then Users is updated to contain J and WriteSet is updated
1199 // to contain any memory locations to which J writes. The function returns
1200 // true if J uses I. By default, alias analysis is used to determine
1201 // whether J reads from memory that overlaps with a location in WriteSet.
1202 // If LoadMoveSet is not null, then it is a previously-computed map
1203 // where the key is the memory-based user instruction and the value is
1204 // the instruction to be compared with I. So, if LoadMoveSet is provided,
1205 // then the alias analysis is not used. This is necessary because this
1206 // function is called during the process of moving instructions during
1207 // vectorization and the results of the alias analysis are not stable during
1208 // that process.
trackUsesOfI(DenseSet<Value * > & Users,AliasSetTracker & WriteSet,Instruction * I,Instruction * J,bool UpdateUsers,DenseSet<ValuePair> * LoadMoveSetPairs)1209 bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users,
1210 AliasSetTracker &WriteSet, Instruction *I,
1211 Instruction *J, bool UpdateUsers,
1212 DenseSet<ValuePair> *LoadMoveSetPairs) {
1213 bool UsesI = false;
1214
1215 // This instruction may already be marked as a user due, for example, to
1216 // being a member of a selected pair.
1217 if (Users.count(J))
1218 UsesI = true;
1219
1220 if (!UsesI)
1221 for (User::op_iterator JU = J->op_begin(), JE = J->op_end();
1222 JU != JE; ++JU) {
1223 Value *V = *JU;
1224 if (I == V || Users.count(V)) {
1225 UsesI = true;
1226 break;
1227 }
1228 }
1229 if (!UsesI && J->mayReadFromMemory()) {
1230 if (LoadMoveSetPairs) {
1231 UsesI = LoadMoveSetPairs->count(ValuePair(J, I));
1232 } else {
1233 for (AliasSetTracker::iterator W = WriteSet.begin(),
1234 WE = WriteSet.end(); W != WE; ++W) {
1235 if (W->aliasesUnknownInst(J, *AA)) {
1236 UsesI = true;
1237 break;
1238 }
1239 }
1240 }
1241 }
1242
1243 if (UsesI && UpdateUsers) {
1244 if (J->mayWriteToMemory()) WriteSet.add(J);
1245 Users.insert(J);
1246 }
1247
1248 return UsesI;
1249 }
1250
1251 // This function iterates over all instruction pairs in the provided
1252 // basic block and collects all candidate pairs for vectorization.
getCandidatePairs(BasicBlock & BB,BasicBlock::iterator & Start,DenseMap<Value *,std::vector<Value * >> & CandidatePairs,DenseSet<ValuePair> & FixedOrderPairs,DenseMap<ValuePair,int> & CandidatePairCostSavings,std::vector<Value * > & PairableInsts,bool NonPow2Len)1253 bool BBVectorize::getCandidatePairs(BasicBlock &BB,
1254 BasicBlock::iterator &Start,
1255 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
1256 DenseSet<ValuePair> &FixedOrderPairs,
1257 DenseMap<ValuePair, int> &CandidatePairCostSavings,
1258 std::vector<Value *> &PairableInsts, bool NonPow2Len) {
1259 size_t TotalPairs = 0;
1260 BasicBlock::iterator E = BB.end();
1261 if (Start == E) return false;
1262
1263 bool ShouldContinue = false, IAfterStart = false;
1264 for (BasicBlock::iterator I = Start++; I != E; ++I) {
1265 if (I == Start) IAfterStart = true;
1266
1267 bool IsSimpleLoadStore;
1268 if (!isInstVectorizable(&*I, IsSimpleLoadStore))
1269 continue;
1270
1271 // Look for an instruction with which to pair instruction *I...
1272 DenseSet<Value *> Users;
1273 AliasSetTracker WriteSet(*AA);
1274 if (I->mayWriteToMemory())
1275 WriteSet.add(&*I);
1276
1277 bool JAfterStart = IAfterStart;
1278 BasicBlock::iterator J = std::next(I);
1279 for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) {
1280 if (J == Start)
1281 JAfterStart = true;
1282
1283 // Determine if J uses I, if so, exit the loop.
1284 bool UsesI = trackUsesOfI(Users, WriteSet, &*I, &*J, !Config.FastDep);
1285 if (Config.FastDep) {
1286 // Note: For this heuristic to be effective, independent operations
1287 // must tend to be intermixed. This is likely to be true from some
1288 // kinds of grouped loop unrolling (but not the generic LLVM pass),
1289 // but otherwise may require some kind of reordering pass.
1290
1291 // When using fast dependency analysis,
1292 // stop searching after first use:
1293 if (UsesI) break;
1294 } else {
1295 if (UsesI) continue;
1296 }
1297
1298 // J does not use I, and comes before the first use of I, so it can be
1299 // merged with I if the instructions are compatible.
1300 int CostSavings, FixedOrder;
1301 if (!areInstsCompatible(&*I, &*J, IsSimpleLoadStore, NonPow2Len,
1302 CostSavings, FixedOrder))
1303 continue;
1304
1305 // J is a candidate for merging with I.
1306 if (PairableInsts.empty() ||
1307 PairableInsts[PairableInsts.size() - 1] != &*I) {
1308 PairableInsts.push_back(&*I);
1309 }
1310
1311 CandidatePairs[&*I].push_back(&*J);
1312 ++TotalPairs;
1313 if (TTI)
1314 CandidatePairCostSavings.insert(
1315 ValuePairWithCost(ValuePair(&*I, &*J), CostSavings));
1316
1317 if (FixedOrder == 1)
1318 FixedOrderPairs.insert(ValuePair(&*I, &*J));
1319 else if (FixedOrder == -1)
1320 FixedOrderPairs.insert(ValuePair(&*J, &*I));
1321
1322 // The next call to this function must start after the last instruction
1323 // selected during this invocation.
1324 if (JAfterStart) {
1325 Start = std::next(J);
1326 IAfterStart = JAfterStart = false;
1327 }
1328
1329 DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair "
1330 << *I << " <-> " << *J << " (cost savings: " <<
1331 CostSavings << ")\n");
1332
1333 // If we have already found too many pairs, break here and this function
1334 // will be called again starting after the last instruction selected
1335 // during this invocation.
1336 if (PairableInsts.size() >= Config.MaxInsts ||
1337 TotalPairs >= Config.MaxPairs) {
1338 ShouldContinue = true;
1339 break;
1340 }
1341 }
1342
1343 if (ShouldContinue)
1344 break;
1345 }
1346
1347 DEBUG(dbgs() << "BBV: found " << PairableInsts.size()
1348 << " instructions with candidate pairs\n");
1349
1350 return ShouldContinue;
1351 }
1352
1353 // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that
1354 // it looks for pairs such that both members have an input which is an
1355 // output of PI or PJ.
computePairsConnectedTo(DenseMap<Value *,std::vector<Value * >> & CandidatePairs,DenseSet<ValuePair> & CandidatePairsSet,std::vector<Value * > & PairableInsts,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairs,DenseMap<VPPair,unsigned> & PairConnectionTypes,ValuePair P)1356 void BBVectorize::computePairsConnectedTo(
1357 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
1358 DenseSet<ValuePair> &CandidatePairsSet,
1359 std::vector<Value *> &PairableInsts,
1360 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
1361 DenseMap<VPPair, unsigned> &PairConnectionTypes,
1362 ValuePair P) {
1363 StoreInst *SI, *SJ;
1364
1365 // For each possible pairing for this variable, look at the uses of
1366 // the first value...
1367 for (Value::user_iterator I = P.first->user_begin(),
1368 E = P.first->user_end();
1369 I != E; ++I) {
1370 User *UI = *I;
1371 if (isa<LoadInst>(UI)) {
1372 // A pair cannot be connected to a load because the load only takes one
1373 // operand (the address) and it is a scalar even after vectorization.
1374 continue;
1375 } else if ((SI = dyn_cast<StoreInst>(UI)) &&
1376 P.first == SI->getPointerOperand()) {
1377 // Similarly, a pair cannot be connected to a store through its
1378 // pointer operand.
1379 continue;
1380 }
1381
1382 // For each use of the first variable, look for uses of the second
1383 // variable...
1384 for (User *UJ : P.second->users()) {
1385 if ((SJ = dyn_cast<StoreInst>(UJ)) &&
1386 P.second == SJ->getPointerOperand())
1387 continue;
1388
1389 // Look for <I, J>:
1390 if (CandidatePairsSet.count(ValuePair(UI, UJ))) {
1391 VPPair VP(P, ValuePair(UI, UJ));
1392 ConnectedPairs[VP.first].push_back(VP.second);
1393 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect));
1394 }
1395
1396 // Look for <J, I>:
1397 if (CandidatePairsSet.count(ValuePair(UJ, UI))) {
1398 VPPair VP(P, ValuePair(UJ, UI));
1399 ConnectedPairs[VP.first].push_back(VP.second);
1400 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap));
1401 }
1402 }
1403
1404 if (Config.SplatBreaksChain) continue;
1405 // Look for cases where just the first value in the pair is used by
1406 // both members of another pair (splatting).
1407 for (Value::user_iterator J = P.first->user_begin(); J != E; ++J) {
1408 User *UJ = *J;
1409 if ((SJ = dyn_cast<StoreInst>(UJ)) &&
1410 P.first == SJ->getPointerOperand())
1411 continue;
1412
1413 if (CandidatePairsSet.count(ValuePair(UI, UJ))) {
1414 VPPair VP(P, ValuePair(UI, UJ));
1415 ConnectedPairs[VP.first].push_back(VP.second);
1416 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
1417 }
1418 }
1419 }
1420
1421 if (Config.SplatBreaksChain) return;
1422 // Look for cases where just the second value in the pair is used by
1423 // both members of another pair (splatting).
1424 for (Value::user_iterator I = P.second->user_begin(),
1425 E = P.second->user_end();
1426 I != E; ++I) {
1427 User *UI = *I;
1428 if (isa<LoadInst>(UI))
1429 continue;
1430 else if ((SI = dyn_cast<StoreInst>(UI)) &&
1431 P.second == SI->getPointerOperand())
1432 continue;
1433
1434 for (Value::user_iterator J = P.second->user_begin(); J != E; ++J) {
1435 User *UJ = *J;
1436 if ((SJ = dyn_cast<StoreInst>(UJ)) &&
1437 P.second == SJ->getPointerOperand())
1438 continue;
1439
1440 if (CandidatePairsSet.count(ValuePair(UI, UJ))) {
1441 VPPair VP(P, ValuePair(UI, UJ));
1442 ConnectedPairs[VP.first].push_back(VP.second);
1443 PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
1444 }
1445 }
1446 }
1447 }
1448
1449 // This function figures out which pairs are connected. Two pairs are
1450 // connected if some output of the first pair forms an input to both members
1451 // of the second pair.
computeConnectedPairs(DenseMap<Value *,std::vector<Value * >> & CandidatePairs,DenseSet<ValuePair> & CandidatePairsSet,std::vector<Value * > & PairableInsts,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairs,DenseMap<VPPair,unsigned> & PairConnectionTypes)1452 void BBVectorize::computeConnectedPairs(
1453 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
1454 DenseSet<ValuePair> &CandidatePairsSet,
1455 std::vector<Value *> &PairableInsts,
1456 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
1457 DenseMap<VPPair, unsigned> &PairConnectionTypes) {
1458 for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
1459 PE = PairableInsts.end(); PI != PE; ++PI) {
1460 DenseMap<Value *, std::vector<Value *> >::iterator PP =
1461 CandidatePairs.find(*PI);
1462 if (PP == CandidatePairs.end())
1463 continue;
1464
1465 for (std::vector<Value *>::iterator P = PP->second.begin(),
1466 E = PP->second.end(); P != E; ++P)
1467 computePairsConnectedTo(CandidatePairs, CandidatePairsSet,
1468 PairableInsts, ConnectedPairs,
1469 PairConnectionTypes, ValuePair(*PI, *P));
1470 }
1471
1472 DEBUG(size_t TotalPairs = 0;
1473 for (DenseMap<ValuePair, std::vector<ValuePair> >::iterator I =
1474 ConnectedPairs.begin(), IE = ConnectedPairs.end(); I != IE; ++I)
1475 TotalPairs += I->second.size();
1476 dbgs() << "BBV: found " << TotalPairs
1477 << " pair connections.\n");
1478 }
1479
1480 // This function builds a set of use tuples such that <A, B> is in the set
1481 // if B is in the use dag of A. If B is in the use dag of A, then B
1482 // depends on the output of A.
buildDepMap(BasicBlock & BB,DenseMap<Value *,std::vector<Value * >> & CandidatePairs,std::vector<Value * > & PairableInsts,DenseSet<ValuePair> & PairableInstUsers)1483 void BBVectorize::buildDepMap(
1484 BasicBlock &BB,
1485 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
1486 std::vector<Value *> &PairableInsts,
1487 DenseSet<ValuePair> &PairableInstUsers) {
1488 DenseSet<Value *> IsInPair;
1489 for (DenseMap<Value *, std::vector<Value *> >::iterator C =
1490 CandidatePairs.begin(), E = CandidatePairs.end(); C != E; ++C) {
1491 IsInPair.insert(C->first);
1492 IsInPair.insert(C->second.begin(), C->second.end());
1493 }
1494
1495 // Iterate through the basic block, recording all users of each
1496 // pairable instruction.
1497
1498 BasicBlock::iterator E = BB.end(), EL =
1499 BasicBlock::iterator(cast<Instruction>(PairableInsts.back()));
1500 for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) {
1501 if (IsInPair.find(&*I) == IsInPair.end())
1502 continue;
1503
1504 DenseSet<Value *> Users;
1505 AliasSetTracker WriteSet(*AA);
1506 if (I->mayWriteToMemory())
1507 WriteSet.add(&*I);
1508
1509 for (BasicBlock::iterator J = std::next(I); J != E; ++J) {
1510 (void)trackUsesOfI(Users, WriteSet, &*I, &*J);
1511
1512 if (J == EL)
1513 break;
1514 }
1515
1516 for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end();
1517 U != E; ++U) {
1518 if (IsInPair.find(*U) == IsInPair.end()) continue;
1519 PairableInstUsers.insert(ValuePair(&*I, *U));
1520 }
1521
1522 if (I == EL)
1523 break;
1524 }
1525 }
1526
1527 // Returns true if an input to pair P is an output of pair Q and also an
1528 // input of pair Q is an output of pair P. If this is the case, then these
1529 // two pairs cannot be simultaneously fused.
pairsConflict(ValuePair P,ValuePair Q,DenseSet<ValuePair> & PairableInstUsers,DenseMap<ValuePair,std::vector<ValuePair>> * PairableInstUserMap,DenseSet<VPPair> * PairableInstUserPairSet)1530 bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q,
1531 DenseSet<ValuePair> &PairableInstUsers,
1532 DenseMap<ValuePair, std::vector<ValuePair> > *PairableInstUserMap,
1533 DenseSet<VPPair> *PairableInstUserPairSet) {
1534 // Two pairs are in conflict if they are mutual Users of eachother.
1535 bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) ||
1536 PairableInstUsers.count(ValuePair(P.first, Q.second)) ||
1537 PairableInstUsers.count(ValuePair(P.second, Q.first)) ||
1538 PairableInstUsers.count(ValuePair(P.second, Q.second));
1539 bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) ||
1540 PairableInstUsers.count(ValuePair(Q.first, P.second)) ||
1541 PairableInstUsers.count(ValuePair(Q.second, P.first)) ||
1542 PairableInstUsers.count(ValuePair(Q.second, P.second));
1543 if (PairableInstUserMap) {
1544 // FIXME: The expensive part of the cycle check is not so much the cycle
1545 // check itself but this edge insertion procedure. This needs some
1546 // profiling and probably a different data structure.
1547 if (PUsesQ) {
1548 if (PairableInstUserPairSet->insert(VPPair(Q, P)).second)
1549 (*PairableInstUserMap)[Q].push_back(P);
1550 }
1551 if (QUsesP) {
1552 if (PairableInstUserPairSet->insert(VPPair(P, Q)).second)
1553 (*PairableInstUserMap)[P].push_back(Q);
1554 }
1555 }
1556
1557 return (QUsesP && PUsesQ);
1558 }
1559
1560 // This function walks the use graph of current pairs to see if, starting
1561 // from P, the walk returns to P.
pairWillFormCycle(ValuePair P,DenseMap<ValuePair,std::vector<ValuePair>> & PairableInstUserMap,DenseSet<ValuePair> & CurrentPairs)1562 bool BBVectorize::pairWillFormCycle(ValuePair P,
1563 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
1564 DenseSet<ValuePair> &CurrentPairs) {
1565 DEBUG(if (DebugCycleCheck)
1566 dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> "
1567 << *P.second << "\n");
1568 // A lookup table of visisted pairs is kept because the PairableInstUserMap
1569 // contains non-direct associations.
1570 DenseSet<ValuePair> Visited;
1571 SmallVector<ValuePair, 32> Q;
1572 // General depth-first post-order traversal:
1573 Q.push_back(P);
1574 do {
1575 ValuePair QTop = Q.pop_back_val();
1576 Visited.insert(QTop);
1577
1578 DEBUG(if (DebugCycleCheck)
1579 dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> "
1580 << *QTop.second << "\n");
1581 DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ =
1582 PairableInstUserMap.find(QTop);
1583 if (QQ == PairableInstUserMap.end())
1584 continue;
1585
1586 for (std::vector<ValuePair>::iterator C = QQ->second.begin(),
1587 CE = QQ->second.end(); C != CE; ++C) {
1588 if (*C == P) {
1589 DEBUG(dbgs()
1590 << "BBV: rejected to prevent non-trivial cycle formation: "
1591 << QTop.first << " <-> " << C->second << "\n");
1592 return true;
1593 }
1594
1595 if (CurrentPairs.count(*C) && !Visited.count(*C))
1596 Q.push_back(*C);
1597 }
1598 } while (!Q.empty());
1599
1600 return false;
1601 }
1602
1603 // This function builds the initial dag of connected pairs with the
1604 // pair J at the root.
buildInitialDAGFor(DenseMap<Value *,std::vector<Value * >> & CandidatePairs,DenseSet<ValuePair> & CandidatePairsSet,std::vector<Value * > & PairableInsts,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairs,DenseSet<ValuePair> & PairableInstUsers,DenseMap<Value *,Value * > & ChosenPairs,DenseMap<ValuePair,size_t> & DAG,ValuePair J)1605 void BBVectorize::buildInitialDAGFor(
1606 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
1607 DenseSet<ValuePair> &CandidatePairsSet,
1608 std::vector<Value *> &PairableInsts,
1609 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
1610 DenseSet<ValuePair> &PairableInstUsers,
1611 DenseMap<Value *, Value *> &ChosenPairs,
1612 DenseMap<ValuePair, size_t> &DAG, ValuePair J) {
1613 // Each of these pairs is viewed as the root node of a DAG. The DAG
1614 // is then walked (depth-first). As this happens, we keep track of
1615 // the pairs that compose the DAG and the maximum depth of the DAG.
1616 SmallVector<ValuePairWithDepth, 32> Q;
1617 // General depth-first post-order traversal:
1618 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
1619 do {
1620 ValuePairWithDepth QTop = Q.back();
1621
1622 // Push each child onto the queue:
1623 bool MoreChildren = false;
1624 size_t MaxChildDepth = QTop.second;
1625 DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ =
1626 ConnectedPairs.find(QTop.first);
1627 if (QQ != ConnectedPairs.end())
1628 for (std::vector<ValuePair>::iterator k = QQ->second.begin(),
1629 ke = QQ->second.end(); k != ke; ++k) {
1630 // Make sure that this child pair is still a candidate:
1631 if (CandidatePairsSet.count(*k)) {
1632 DenseMap<ValuePair, size_t>::iterator C = DAG.find(*k);
1633 if (C == DAG.end()) {
1634 size_t d = getDepthFactor(k->first);
1635 Q.push_back(ValuePairWithDepth(*k, QTop.second+d));
1636 MoreChildren = true;
1637 } else {
1638 MaxChildDepth = std::max(MaxChildDepth, C->second);
1639 }
1640 }
1641 }
1642
1643 if (!MoreChildren) {
1644 // Record the current pair as part of the DAG:
1645 DAG.insert(ValuePairWithDepth(QTop.first, MaxChildDepth));
1646 Q.pop_back();
1647 }
1648 } while (!Q.empty());
1649 }
1650
1651 // Given some initial dag, prune it by removing conflicting pairs (pairs
1652 // that cannot be simultaneously chosen for vectorization).
pruneDAGFor(DenseMap<Value *,std::vector<Value * >> & CandidatePairs,std::vector<Value * > & PairableInsts,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairs,DenseSet<ValuePair> & PairableInstUsers,DenseMap<ValuePair,std::vector<ValuePair>> & PairableInstUserMap,DenseSet<VPPair> & PairableInstUserPairSet,DenseMap<Value *,Value * > & ChosenPairs,DenseMap<ValuePair,size_t> & DAG,DenseSet<ValuePair> & PrunedDAG,ValuePair J,bool UseCycleCheck)1653 void BBVectorize::pruneDAGFor(
1654 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
1655 std::vector<Value *> &PairableInsts,
1656 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
1657 DenseSet<ValuePair> &PairableInstUsers,
1658 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
1659 DenseSet<VPPair> &PairableInstUserPairSet,
1660 DenseMap<Value *, Value *> &ChosenPairs,
1661 DenseMap<ValuePair, size_t> &DAG,
1662 DenseSet<ValuePair> &PrunedDAG, ValuePair J,
1663 bool UseCycleCheck) {
1664 SmallVector<ValuePairWithDepth, 32> Q;
1665 // General depth-first post-order traversal:
1666 Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
1667 do {
1668 ValuePairWithDepth QTop = Q.pop_back_val();
1669 PrunedDAG.insert(QTop.first);
1670
1671 // Visit each child, pruning as necessary...
1672 SmallVector<ValuePairWithDepth, 8> BestChildren;
1673 DenseMap<ValuePair, std::vector<ValuePair> >::iterator QQ =
1674 ConnectedPairs.find(QTop.first);
1675 if (QQ == ConnectedPairs.end())
1676 continue;
1677
1678 for (std::vector<ValuePair>::iterator K = QQ->second.begin(),
1679 KE = QQ->second.end(); K != KE; ++K) {
1680 DenseMap<ValuePair, size_t>::iterator C = DAG.find(*K);
1681 if (C == DAG.end()) continue;
1682
1683 // This child is in the DAG, now we need to make sure it is the
1684 // best of any conflicting children. There could be multiple
1685 // conflicting children, so first, determine if we're keeping
1686 // this child, then delete conflicting children as necessary.
1687
1688 // It is also necessary to guard against pairing-induced
1689 // dependencies. Consider instructions a .. x .. y .. b
1690 // such that (a,b) are to be fused and (x,y) are to be fused
1691 // but a is an input to x and b is an output from y. This
1692 // means that y cannot be moved after b but x must be moved
1693 // after b for (a,b) to be fused. In other words, after
1694 // fusing (a,b) we have y .. a/b .. x where y is an input
1695 // to a/b and x is an output to a/b: x and y can no longer
1696 // be legally fused. To prevent this condition, we must
1697 // make sure that a child pair added to the DAG is not
1698 // both an input and output of an already-selected pair.
1699
1700 // Pairing-induced dependencies can also form from more complicated
1701 // cycles. The pair vs. pair conflicts are easy to check, and so
1702 // that is done explicitly for "fast rejection", and because for
1703 // child vs. child conflicts, we may prefer to keep the current
1704 // pair in preference to the already-selected child.
1705 DenseSet<ValuePair> CurrentPairs;
1706
1707 bool CanAdd = true;
1708 for (SmallVectorImpl<ValuePairWithDepth>::iterator C2
1709 = BestChildren.begin(), E2 = BestChildren.end();
1710 C2 != E2; ++C2) {
1711 if (C2->first.first == C->first.first ||
1712 C2->first.first == C->first.second ||
1713 C2->first.second == C->first.first ||
1714 C2->first.second == C->first.second ||
1715 pairsConflict(C2->first, C->first, PairableInstUsers,
1716 UseCycleCheck ? &PairableInstUserMap : nullptr,
1717 UseCycleCheck ? &PairableInstUserPairSet
1718 : nullptr)) {
1719 if (C2->second >= C->second) {
1720 CanAdd = false;
1721 break;
1722 }
1723
1724 CurrentPairs.insert(C2->first);
1725 }
1726 }
1727 if (!CanAdd) continue;
1728
1729 // Even worse, this child could conflict with another node already
1730 // selected for the DAG. If that is the case, ignore this child.
1731 for (DenseSet<ValuePair>::iterator T = PrunedDAG.begin(),
1732 E2 = PrunedDAG.end(); T != E2; ++T) {
1733 if (T->first == C->first.first ||
1734 T->first == C->first.second ||
1735 T->second == C->first.first ||
1736 T->second == C->first.second ||
1737 pairsConflict(*T, C->first, PairableInstUsers,
1738 UseCycleCheck ? &PairableInstUserMap : nullptr,
1739 UseCycleCheck ? &PairableInstUserPairSet
1740 : nullptr)) {
1741 CanAdd = false;
1742 break;
1743 }
1744
1745 CurrentPairs.insert(*T);
1746 }
1747 if (!CanAdd) continue;
1748
1749 // And check the queue too...
1750 for (SmallVectorImpl<ValuePairWithDepth>::iterator C2 = Q.begin(),
1751 E2 = Q.end(); C2 != E2; ++C2) {
1752 if (C2->first.first == C->first.first ||
1753 C2->first.first == C->first.second ||
1754 C2->first.second == C->first.first ||
1755 C2->first.second == C->first.second ||
1756 pairsConflict(C2->first, C->first, PairableInstUsers,
1757 UseCycleCheck ? &PairableInstUserMap : nullptr,
1758 UseCycleCheck ? &PairableInstUserPairSet
1759 : nullptr)) {
1760 CanAdd = false;
1761 break;
1762 }
1763
1764 CurrentPairs.insert(C2->first);
1765 }
1766 if (!CanAdd) continue;
1767
1768 // Last but not least, check for a conflict with any of the
1769 // already-chosen pairs.
1770 for (DenseMap<Value *, Value *>::iterator C2 =
1771 ChosenPairs.begin(), E2 = ChosenPairs.end();
1772 C2 != E2; ++C2) {
1773 if (pairsConflict(*C2, C->first, PairableInstUsers,
1774 UseCycleCheck ? &PairableInstUserMap : nullptr,
1775 UseCycleCheck ? &PairableInstUserPairSet
1776 : nullptr)) {
1777 CanAdd = false;
1778 break;
1779 }
1780
1781 CurrentPairs.insert(*C2);
1782 }
1783 if (!CanAdd) continue;
1784
1785 // To check for non-trivial cycles formed by the addition of the
1786 // current pair we've formed a list of all relevant pairs, now use a
1787 // graph walk to check for a cycle. We start from the current pair and
1788 // walk the use dag to see if we again reach the current pair. If we
1789 // do, then the current pair is rejected.
1790
1791 // FIXME: It may be more efficient to use a topological-ordering
1792 // algorithm to improve the cycle check. This should be investigated.
1793 if (UseCycleCheck &&
1794 pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs))
1795 continue;
1796
1797 // This child can be added, but we may have chosen it in preference
1798 // to an already-selected child. Check for this here, and if a
1799 // conflict is found, then remove the previously-selected child
1800 // before adding this one in its place.
1801 for (SmallVectorImpl<ValuePairWithDepth>::iterator C2
1802 = BestChildren.begin(); C2 != BestChildren.end();) {
1803 if (C2->first.first == C->first.first ||
1804 C2->first.first == C->first.second ||
1805 C2->first.second == C->first.first ||
1806 C2->first.second == C->first.second ||
1807 pairsConflict(C2->first, C->first, PairableInstUsers))
1808 C2 = BestChildren.erase(C2);
1809 else
1810 ++C2;
1811 }
1812
1813 BestChildren.push_back(ValuePairWithDepth(C->first, C->second));
1814 }
1815
1816 for (SmallVectorImpl<ValuePairWithDepth>::iterator C
1817 = BestChildren.begin(), E2 = BestChildren.end();
1818 C != E2; ++C) {
1819 size_t DepthF = getDepthFactor(C->first.first);
1820 Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF));
1821 }
1822 } while (!Q.empty());
1823 }
1824
1825 // This function finds the best dag of mututally-compatible connected
1826 // pairs, given the choice of root pairs as an iterator range.
findBestDAGFor(DenseMap<Value *,std::vector<Value * >> & CandidatePairs,DenseSet<ValuePair> & CandidatePairsSet,DenseMap<ValuePair,int> & CandidatePairCostSavings,std::vector<Value * > & PairableInsts,DenseSet<ValuePair> & FixedOrderPairs,DenseMap<VPPair,unsigned> & PairConnectionTypes,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairs,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairDeps,DenseSet<ValuePair> & PairableInstUsers,DenseMap<ValuePair,std::vector<ValuePair>> & PairableInstUserMap,DenseSet<VPPair> & PairableInstUserPairSet,DenseMap<Value *,Value * > & ChosenPairs,DenseSet<ValuePair> & BestDAG,size_t & BestMaxDepth,int & BestEffSize,Value * II,std::vector<Value * > & JJ,bool UseCycleCheck)1827 void BBVectorize::findBestDAGFor(
1828 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
1829 DenseSet<ValuePair> &CandidatePairsSet,
1830 DenseMap<ValuePair, int> &CandidatePairCostSavings,
1831 std::vector<Value *> &PairableInsts,
1832 DenseSet<ValuePair> &FixedOrderPairs,
1833 DenseMap<VPPair, unsigned> &PairConnectionTypes,
1834 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
1835 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
1836 DenseSet<ValuePair> &PairableInstUsers,
1837 DenseMap<ValuePair, std::vector<ValuePair> > &PairableInstUserMap,
1838 DenseSet<VPPair> &PairableInstUserPairSet,
1839 DenseMap<Value *, Value *> &ChosenPairs,
1840 DenseSet<ValuePair> &BestDAG, size_t &BestMaxDepth,
1841 int &BestEffSize, Value *II, std::vector<Value *>&JJ,
1842 bool UseCycleCheck) {
1843 for (std::vector<Value *>::iterator J = JJ.begin(), JE = JJ.end();
1844 J != JE; ++J) {
1845 ValuePair IJ(II, *J);
1846 if (!CandidatePairsSet.count(IJ))
1847 continue;
1848
1849 // Before going any further, make sure that this pair does not
1850 // conflict with any already-selected pairs (see comment below
1851 // near the DAG pruning for more details).
1852 DenseSet<ValuePair> ChosenPairSet;
1853 bool DoesConflict = false;
1854 for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(),
1855 E = ChosenPairs.end(); C != E; ++C) {
1856 if (pairsConflict(*C, IJ, PairableInstUsers,
1857 UseCycleCheck ? &PairableInstUserMap : nullptr,
1858 UseCycleCheck ? &PairableInstUserPairSet : nullptr)) {
1859 DoesConflict = true;
1860 break;
1861 }
1862
1863 ChosenPairSet.insert(*C);
1864 }
1865 if (DoesConflict) continue;
1866
1867 if (UseCycleCheck &&
1868 pairWillFormCycle(IJ, PairableInstUserMap, ChosenPairSet))
1869 continue;
1870
1871 DenseMap<ValuePair, size_t> DAG;
1872 buildInitialDAGFor(CandidatePairs, CandidatePairsSet,
1873 PairableInsts, ConnectedPairs,
1874 PairableInstUsers, ChosenPairs, DAG, IJ);
1875
1876 // Because we'll keep the child with the largest depth, the largest
1877 // depth is still the same in the unpruned DAG.
1878 size_t MaxDepth = DAG.lookup(IJ);
1879
1880 DEBUG(if (DebugPairSelection) dbgs() << "BBV: found DAG for pair {"
1881 << *IJ.first << " <-> " << *IJ.second << "} of depth " <<
1882 MaxDepth << " and size " << DAG.size() << "\n");
1883
1884 // At this point the DAG has been constructed, but, may contain
1885 // contradictory children (meaning that different children of
1886 // some dag node may be attempting to fuse the same instruction).
1887 // So now we walk the dag again, in the case of a conflict,
1888 // keep only the child with the largest depth. To break a tie,
1889 // favor the first child.
1890
1891 DenseSet<ValuePair> PrunedDAG;
1892 pruneDAGFor(CandidatePairs, PairableInsts, ConnectedPairs,
1893 PairableInstUsers, PairableInstUserMap,
1894 PairableInstUserPairSet,
1895 ChosenPairs, DAG, PrunedDAG, IJ, UseCycleCheck);
1896
1897 int EffSize = 0;
1898 if (TTI) {
1899 DenseSet<Value *> PrunedDAGInstrs;
1900 for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(),
1901 E = PrunedDAG.end(); S != E; ++S) {
1902 PrunedDAGInstrs.insert(S->first);
1903 PrunedDAGInstrs.insert(S->second);
1904 }
1905
1906 // The set of pairs that have already contributed to the total cost.
1907 DenseSet<ValuePair> IncomingPairs;
1908
1909 // If the cost model were perfect, this might not be necessary; but we
1910 // need to make sure that we don't get stuck vectorizing our own
1911 // shuffle chains.
1912 bool HasNontrivialInsts = false;
1913
1914 // The node weights represent the cost savings associated with
1915 // fusing the pair of instructions.
1916 for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(),
1917 E = PrunedDAG.end(); S != E; ++S) {
1918 if (!isa<ShuffleVectorInst>(S->first) &&
1919 !isa<InsertElementInst>(S->first) &&
1920 !isa<ExtractElementInst>(S->first))
1921 HasNontrivialInsts = true;
1922
1923 bool FlipOrder = false;
1924
1925 if (getDepthFactor(S->first)) {
1926 int ESContrib = CandidatePairCostSavings.find(*S)->second;
1927 DEBUG(if (DebugPairSelection) dbgs() << "\tweight {"
1928 << *S->first << " <-> " << *S->second << "} = " <<
1929 ESContrib << "\n");
1930 EffSize += ESContrib;
1931 }
1932
1933 // The edge weights contribute in a negative sense: they represent
1934 // the cost of shuffles.
1935 DenseMap<ValuePair, std::vector<ValuePair> >::iterator SS =
1936 ConnectedPairDeps.find(*S);
1937 if (SS != ConnectedPairDeps.end()) {
1938 unsigned NumDepsDirect = 0, NumDepsSwap = 0;
1939 for (std::vector<ValuePair>::iterator T = SS->second.begin(),
1940 TE = SS->second.end(); T != TE; ++T) {
1941 VPPair Q(*S, *T);
1942 if (!PrunedDAG.count(Q.second))
1943 continue;
1944 DenseMap<VPPair, unsigned>::iterator R =
1945 PairConnectionTypes.find(VPPair(Q.second, Q.first));
1946 assert(R != PairConnectionTypes.end() &&
1947 "Cannot find pair connection type");
1948 if (R->second == PairConnectionDirect)
1949 ++NumDepsDirect;
1950 else if (R->second == PairConnectionSwap)
1951 ++NumDepsSwap;
1952 }
1953
1954 // If there are more swaps than direct connections, then
1955 // the pair order will be flipped during fusion. So the real
1956 // number of swaps is the minimum number.
1957 FlipOrder = !FixedOrderPairs.count(*S) &&
1958 ((NumDepsSwap > NumDepsDirect) ||
1959 FixedOrderPairs.count(ValuePair(S->second, S->first)));
1960
1961 for (std::vector<ValuePair>::iterator T = SS->second.begin(),
1962 TE = SS->second.end(); T != TE; ++T) {
1963 VPPair Q(*S, *T);
1964 if (!PrunedDAG.count(Q.second))
1965 continue;
1966 DenseMap<VPPair, unsigned>::iterator R =
1967 PairConnectionTypes.find(VPPair(Q.second, Q.first));
1968 assert(R != PairConnectionTypes.end() &&
1969 "Cannot find pair connection type");
1970 Type *Ty1 = Q.second.first->getType(),
1971 *Ty2 = Q.second.second->getType();
1972 Type *VTy = getVecTypeForPair(Ty1, Ty2);
1973 if ((R->second == PairConnectionDirect && FlipOrder) ||
1974 (R->second == PairConnectionSwap && !FlipOrder) ||
1975 R->second == PairConnectionSplat) {
1976 int ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
1977 VTy, VTy);
1978
1979 if (VTy->getVectorNumElements() == 2) {
1980 if (R->second == PairConnectionSplat)
1981 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
1982 TargetTransformInfo::SK_Broadcast, VTy));
1983 else
1984 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
1985 TargetTransformInfo::SK_Reverse, VTy));
1986 }
1987
1988 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
1989 *Q.second.first << " <-> " << *Q.second.second <<
1990 "} -> {" <<
1991 *S->first << " <-> " << *S->second << "} = " <<
1992 ESContrib << "\n");
1993 EffSize -= ESContrib;
1994 }
1995 }
1996 }
1997
1998 // Compute the cost of outgoing edges. We assume that edges outgoing
1999 // to shuffles, inserts or extracts can be merged, and so contribute
2000 // no additional cost.
2001 if (!S->first->getType()->isVoidTy()) {
2002 Type *Ty1 = S->first->getType(),
2003 *Ty2 = S->second->getType();
2004 Type *VTy = getVecTypeForPair(Ty1, Ty2);
2005
2006 bool NeedsExtraction = false;
2007 for (User *U : S->first->users()) {
2008 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(U)) {
2009 // Shuffle can be folded if it has no other input
2010 if (isa<UndefValue>(SI->getOperand(1)))
2011 continue;
2012 }
2013 if (isa<ExtractElementInst>(U))
2014 continue;
2015 if (PrunedDAGInstrs.count(U))
2016 continue;
2017 NeedsExtraction = true;
2018 break;
2019 }
2020
2021 if (NeedsExtraction) {
2022 int ESContrib;
2023 if (Ty1->isVectorTy()) {
2024 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
2025 Ty1, VTy);
2026 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
2027 TargetTransformInfo::SK_ExtractSubvector, VTy, 0, Ty1));
2028 } else
2029 ESContrib = (int) TTI->getVectorInstrCost(
2030 Instruction::ExtractElement, VTy, 0);
2031
2032 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
2033 *S->first << "} = " << ESContrib << "\n");
2034 EffSize -= ESContrib;
2035 }
2036
2037 NeedsExtraction = false;
2038 for (User *U : S->second->users()) {
2039 if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(U)) {
2040 // Shuffle can be folded if it has no other input
2041 if (isa<UndefValue>(SI->getOperand(1)))
2042 continue;
2043 }
2044 if (isa<ExtractElementInst>(U))
2045 continue;
2046 if (PrunedDAGInstrs.count(U))
2047 continue;
2048 NeedsExtraction = true;
2049 break;
2050 }
2051
2052 if (NeedsExtraction) {
2053 int ESContrib;
2054 if (Ty2->isVectorTy()) {
2055 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
2056 Ty2, VTy);
2057 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
2058 TargetTransformInfo::SK_ExtractSubvector, VTy,
2059 Ty1->isVectorTy() ? Ty1->getVectorNumElements() : 1, Ty2));
2060 } else
2061 ESContrib = (int) TTI->getVectorInstrCost(
2062 Instruction::ExtractElement, VTy, 1);
2063 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
2064 *S->second << "} = " << ESContrib << "\n");
2065 EffSize -= ESContrib;
2066 }
2067 }
2068
2069 // Compute the cost of incoming edges.
2070 if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) {
2071 Instruction *S1 = cast<Instruction>(S->first),
2072 *S2 = cast<Instruction>(S->second);
2073 for (unsigned o = 0; o < S1->getNumOperands(); ++o) {
2074 Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o);
2075
2076 // Combining constants into vector constants (or small vector
2077 // constants into larger ones are assumed free).
2078 if (isa<Constant>(O1) && isa<Constant>(O2))
2079 continue;
2080
2081 if (FlipOrder)
2082 std::swap(O1, O2);
2083
2084 ValuePair VP = ValuePair(O1, O2);
2085 ValuePair VPR = ValuePair(O2, O1);
2086
2087 // Internal edges are not handled here.
2088 if (PrunedDAG.count(VP) || PrunedDAG.count(VPR))
2089 continue;
2090
2091 Type *Ty1 = O1->getType(),
2092 *Ty2 = O2->getType();
2093 Type *VTy = getVecTypeForPair(Ty1, Ty2);
2094
2095 // Combining vector operations of the same type is also assumed
2096 // folded with other operations.
2097 if (Ty1 == Ty2) {
2098 // If both are insert elements, then both can be widened.
2099 InsertElementInst *IEO1 = dyn_cast<InsertElementInst>(O1),
2100 *IEO2 = dyn_cast<InsertElementInst>(O2);
2101 if (IEO1 && IEO2 && isPureIEChain(IEO1) && isPureIEChain(IEO2))
2102 continue;
2103 // If both are extract elements, and both have the same input
2104 // type, then they can be replaced with a shuffle
2105 ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1),
2106 *EIO2 = dyn_cast<ExtractElementInst>(O2);
2107 if (EIO1 && EIO2 &&
2108 EIO1->getOperand(0)->getType() ==
2109 EIO2->getOperand(0)->getType())
2110 continue;
2111 // If both are a shuffle with equal operand types and only two
2112 // unqiue operands, then they can be replaced with a single
2113 // shuffle
2114 ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1),
2115 *SIO2 = dyn_cast<ShuffleVectorInst>(O2);
2116 if (SIO1 && SIO2 &&
2117 SIO1->getOperand(0)->getType() ==
2118 SIO2->getOperand(0)->getType()) {
2119 SmallSet<Value *, 4> SIOps;
2120 SIOps.insert(SIO1->getOperand(0));
2121 SIOps.insert(SIO1->getOperand(1));
2122 SIOps.insert(SIO2->getOperand(0));
2123 SIOps.insert(SIO2->getOperand(1));
2124 if (SIOps.size() <= 2)
2125 continue;
2126 }
2127 }
2128
2129 int ESContrib;
2130 // This pair has already been formed.
2131 if (IncomingPairs.count(VP)) {
2132 continue;
2133 } else if (IncomingPairs.count(VPR)) {
2134 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
2135 VTy, VTy);
2136
2137 if (VTy->getVectorNumElements() == 2)
2138 ESContrib = std::min(ESContrib, (int) TTI->getShuffleCost(
2139 TargetTransformInfo::SK_Reverse, VTy));
2140 } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) {
2141 ESContrib = (int) TTI->getVectorInstrCost(
2142 Instruction::InsertElement, VTy, 0);
2143 ESContrib += (int) TTI->getVectorInstrCost(
2144 Instruction::InsertElement, VTy, 1);
2145 } else if (!Ty1->isVectorTy()) {
2146 // O1 needs to be inserted into a vector of size O2, and then
2147 // both need to be shuffled together.
2148 ESContrib = (int) TTI->getVectorInstrCost(
2149 Instruction::InsertElement, Ty2, 0);
2150 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
2151 VTy, Ty2);
2152 } else if (!Ty2->isVectorTy()) {
2153 // O2 needs to be inserted into a vector of size O1, and then
2154 // both need to be shuffled together.
2155 ESContrib = (int) TTI->getVectorInstrCost(
2156 Instruction::InsertElement, Ty1, 0);
2157 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
2158 VTy, Ty1);
2159 } else {
2160 Type *TyBig = Ty1, *TySmall = Ty2;
2161 if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements())
2162 std::swap(TyBig, TySmall);
2163
2164 ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
2165 VTy, TyBig);
2166 if (TyBig != TySmall)
2167 ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
2168 TyBig, TySmall);
2169 }
2170
2171 DEBUG(if (DebugPairSelection) dbgs() << "\tcost {"
2172 << *O1 << " <-> " << *O2 << "} = " <<
2173 ESContrib << "\n");
2174 EffSize -= ESContrib;
2175 IncomingPairs.insert(VP);
2176 }
2177 }
2178 }
2179
2180 if (!HasNontrivialInsts) {
2181 DEBUG(if (DebugPairSelection) dbgs() <<
2182 "\tNo non-trivial instructions in DAG;"
2183 " override to zero effective size\n");
2184 EffSize = 0;
2185 }
2186 } else {
2187 for (DenseSet<ValuePair>::iterator S = PrunedDAG.begin(),
2188 E = PrunedDAG.end(); S != E; ++S)
2189 EffSize += (int) getDepthFactor(S->first);
2190 }
2191
2192 DEBUG(if (DebugPairSelection)
2193 dbgs() << "BBV: found pruned DAG for pair {"
2194 << *IJ.first << " <-> " << *IJ.second << "} of depth " <<
2195 MaxDepth << " and size " << PrunedDAG.size() <<
2196 " (effective size: " << EffSize << ")\n");
2197 if (((TTI && !UseChainDepthWithTI) ||
2198 MaxDepth >= Config.ReqChainDepth) &&
2199 EffSize > 0 && EffSize > BestEffSize) {
2200 BestMaxDepth = MaxDepth;
2201 BestEffSize = EffSize;
2202 BestDAG = PrunedDAG;
2203 }
2204 }
2205 }
2206
2207 // Given the list of candidate pairs, this function selects those
2208 // that will be fused into vector instructions.
choosePairs(DenseMap<Value *,std::vector<Value * >> & CandidatePairs,DenseSet<ValuePair> & CandidatePairsSet,DenseMap<ValuePair,int> & CandidatePairCostSavings,std::vector<Value * > & PairableInsts,DenseSet<ValuePair> & FixedOrderPairs,DenseMap<VPPair,unsigned> & PairConnectionTypes,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairs,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairDeps,DenseSet<ValuePair> & PairableInstUsers,DenseMap<Value *,Value * > & ChosenPairs)2209 void BBVectorize::choosePairs(
2210 DenseMap<Value *, std::vector<Value *> > &CandidatePairs,
2211 DenseSet<ValuePair> &CandidatePairsSet,
2212 DenseMap<ValuePair, int> &CandidatePairCostSavings,
2213 std::vector<Value *> &PairableInsts,
2214 DenseSet<ValuePair> &FixedOrderPairs,
2215 DenseMap<VPPair, unsigned> &PairConnectionTypes,
2216 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
2217 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps,
2218 DenseSet<ValuePair> &PairableInstUsers,
2219 DenseMap<Value *, Value *>& ChosenPairs) {
2220 bool UseCycleCheck =
2221 CandidatePairsSet.size() <= Config.MaxCandPairsForCycleCheck;
2222
2223 DenseMap<Value *, std::vector<Value *> > CandidatePairs2;
2224 for (DenseSet<ValuePair>::iterator I = CandidatePairsSet.begin(),
2225 E = CandidatePairsSet.end(); I != E; ++I) {
2226 std::vector<Value *> &JJ = CandidatePairs2[I->second];
2227 if (JJ.empty()) JJ.reserve(32);
2228 JJ.push_back(I->first);
2229 }
2230
2231 DenseMap<ValuePair, std::vector<ValuePair> > PairableInstUserMap;
2232 DenseSet<VPPair> PairableInstUserPairSet;
2233 for (std::vector<Value *>::iterator I = PairableInsts.begin(),
2234 E = PairableInsts.end(); I != E; ++I) {
2235 // The number of possible pairings for this variable:
2236 size_t NumChoices = CandidatePairs.lookup(*I).size();
2237 if (!NumChoices) continue;
2238
2239 std::vector<Value *> &JJ = CandidatePairs[*I];
2240
2241 // The best pair to choose and its dag:
2242 size_t BestMaxDepth = 0;
2243 int BestEffSize = 0;
2244 DenseSet<ValuePair> BestDAG;
2245 findBestDAGFor(CandidatePairs, CandidatePairsSet,
2246 CandidatePairCostSavings,
2247 PairableInsts, FixedOrderPairs, PairConnectionTypes,
2248 ConnectedPairs, ConnectedPairDeps,
2249 PairableInstUsers, PairableInstUserMap,
2250 PairableInstUserPairSet, ChosenPairs,
2251 BestDAG, BestMaxDepth, BestEffSize, *I, JJ,
2252 UseCycleCheck);
2253
2254 if (BestDAG.empty())
2255 continue;
2256
2257 // A dag has been chosen (or not) at this point. If no dag was
2258 // chosen, then this instruction, I, cannot be paired (and is no longer
2259 // considered).
2260
2261 DEBUG(dbgs() << "BBV: selected pairs in the best DAG for: "
2262 << *cast<Instruction>(*I) << "\n");
2263
2264 for (DenseSet<ValuePair>::iterator S = BestDAG.begin(),
2265 SE2 = BestDAG.end(); S != SE2; ++S) {
2266 // Insert the members of this dag into the list of chosen pairs.
2267 ChosenPairs.insert(ValuePair(S->first, S->second));
2268 DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " <<
2269 *S->second << "\n");
2270
2271 // Remove all candidate pairs that have values in the chosen dag.
2272 std::vector<Value *> &KK = CandidatePairs[S->first];
2273 for (std::vector<Value *>::iterator K = KK.begin(), KE = KK.end();
2274 K != KE; ++K) {
2275 if (*K == S->second)
2276 continue;
2277
2278 CandidatePairsSet.erase(ValuePair(S->first, *K));
2279 }
2280
2281 std::vector<Value *> &LL = CandidatePairs2[S->second];
2282 for (std::vector<Value *>::iterator L = LL.begin(), LE = LL.end();
2283 L != LE; ++L) {
2284 if (*L == S->first)
2285 continue;
2286
2287 CandidatePairsSet.erase(ValuePair(*L, S->second));
2288 }
2289
2290 std::vector<Value *> &MM = CandidatePairs[S->second];
2291 for (std::vector<Value *>::iterator M = MM.begin(), ME = MM.end();
2292 M != ME; ++M) {
2293 assert(*M != S->first && "Flipped pair in candidate list?");
2294 CandidatePairsSet.erase(ValuePair(S->second, *M));
2295 }
2296
2297 std::vector<Value *> &NN = CandidatePairs2[S->first];
2298 for (std::vector<Value *>::iterator N = NN.begin(), NE = NN.end();
2299 N != NE; ++N) {
2300 assert(*N != S->second && "Flipped pair in candidate list?");
2301 CandidatePairsSet.erase(ValuePair(*N, S->first));
2302 }
2303 }
2304 }
2305
2306 DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n");
2307 }
2308
getReplacementName(Instruction * I,bool IsInput,unsigned o,unsigned n=0)2309 std::string getReplacementName(Instruction *I, bool IsInput, unsigned o,
2310 unsigned n = 0) {
2311 if (!I->hasName())
2312 return "";
2313
2314 return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) +
2315 (n > 0 ? "." + utostr(n) : "")).str();
2316 }
2317
2318 // Returns the value that is to be used as the pointer input to the vector
2319 // instruction that fuses I with J.
getReplacementPointerInput(LLVMContext & Context,Instruction * I,Instruction * J,unsigned o)2320 Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context,
2321 Instruction *I, Instruction *J, unsigned o) {
2322 Value *IPtr, *JPtr;
2323 unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
2324 int64_t OffsetInElmts;
2325
2326 // Note: the analysis might fail here, that is why the pair order has
2327 // been precomputed (OffsetInElmts must be unused here).
2328 (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
2329 IAddressSpace, JAddressSpace,
2330 OffsetInElmts, false);
2331
2332 // The pointer value is taken to be the one with the lowest offset.
2333 Value *VPtr = IPtr;
2334
2335 Type *ArgTypeI = IPtr->getType()->getPointerElementType();
2336 Type *ArgTypeJ = JPtr->getType()->getPointerElementType();
2337 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2338 Type *VArgPtrType
2339 = PointerType::get(VArgType,
2340 IPtr->getType()->getPointerAddressSpace());
2341 return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
2342 /* insert before */ I);
2343 }
2344
fillNewShuffleMask(LLVMContext & Context,Instruction * J,unsigned MaskOffset,unsigned NumInElem,unsigned NumInElem1,unsigned IdxOffset,std::vector<Constant * > & Mask)2345 void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
2346 unsigned MaskOffset, unsigned NumInElem,
2347 unsigned NumInElem1, unsigned IdxOffset,
2348 std::vector<Constant*> &Mask) {
2349 unsigned NumElem1 = J->getType()->getVectorNumElements();
2350 for (unsigned v = 0; v < NumElem1; ++v) {
2351 int m = cast<ShuffleVectorInst>(J)->getMaskValue(v);
2352 if (m < 0) {
2353 Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context));
2354 } else {
2355 unsigned mm = m + (int) IdxOffset;
2356 if (m >= (int) NumInElem1)
2357 mm += (int) NumInElem;
2358
2359 Mask[v+MaskOffset] =
2360 ConstantInt::get(Type::getInt32Ty(Context), mm);
2361 }
2362 }
2363 }
2364
2365 // Returns the value that is to be used as the vector-shuffle mask to the
2366 // vector instruction that fuses I with J.
getReplacementShuffleMask(LLVMContext & Context,Instruction * I,Instruction * J)2367 Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context,
2368 Instruction *I, Instruction *J) {
2369 // This is the shuffle mask. We need to append the second
2370 // mask to the first, and the numbers need to be adjusted.
2371
2372 Type *ArgTypeI = I->getType();
2373 Type *ArgTypeJ = J->getType();
2374 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2375
2376 unsigned NumElemI = ArgTypeI->getVectorNumElements();
2377
2378 // Get the total number of elements in the fused vector type.
2379 // By definition, this must equal the number of elements in
2380 // the final mask.
2381 unsigned NumElem = VArgType->getVectorNumElements();
2382 std::vector<Constant*> Mask(NumElem);
2383
2384 Type *OpTypeI = I->getOperand(0)->getType();
2385 unsigned NumInElemI = OpTypeI->getVectorNumElements();
2386 Type *OpTypeJ = J->getOperand(0)->getType();
2387 unsigned NumInElemJ = OpTypeJ->getVectorNumElements();
2388
2389 // The fused vector will be:
2390 // -----------------------------------------------------
2391 // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ |
2392 // -----------------------------------------------------
2393 // from which we'll extract NumElem total elements (where the first NumElemI
2394 // of them come from the mask in I and the remainder come from the mask
2395 // in J.
2396
2397 // For the mask from the first pair...
2398 fillNewShuffleMask(Context, I, 0, NumInElemJ, NumInElemI,
2399 0, Mask);
2400
2401 // For the mask from the second pair...
2402 fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ,
2403 NumInElemI, Mask);
2404
2405 return ConstantVector::get(Mask);
2406 }
2407
expandIEChain(LLVMContext & Context,Instruction * I,Instruction * J,unsigned o,Value * & LOp,unsigned numElemL,Type * ArgTypeL,Type * ArgTypeH,bool IBeforeJ,unsigned IdxOff)2408 bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I,
2409 Instruction *J, unsigned o, Value *&LOp,
2410 unsigned numElemL,
2411 Type *ArgTypeL, Type *ArgTypeH,
2412 bool IBeforeJ, unsigned IdxOff) {
2413 bool ExpandedIEChain = false;
2414 if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) {
2415 // If we have a pure insertelement chain, then this can be rewritten
2416 // into a chain that directly builds the larger type.
2417 if (isPureIEChain(LIE)) {
2418 SmallVector<Value *, 8> VectElemts(numElemL,
2419 UndefValue::get(ArgTypeL->getScalarType()));
2420 InsertElementInst *LIENext = LIE;
2421 do {
2422 unsigned Idx =
2423 cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue();
2424 VectElemts[Idx] = LIENext->getOperand(1);
2425 } while ((LIENext =
2426 dyn_cast<InsertElementInst>(LIENext->getOperand(0))));
2427
2428 LIENext = nullptr;
2429 Value *LIEPrev = UndefValue::get(ArgTypeH);
2430 for (unsigned i = 0; i < numElemL; ++i) {
2431 if (isa<UndefValue>(VectElemts[i])) continue;
2432 LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i],
2433 ConstantInt::get(Type::getInt32Ty(Context),
2434 i + IdxOff),
2435 getReplacementName(IBeforeJ ? I : J,
2436 true, o, i+1));
2437 LIENext->insertBefore(IBeforeJ ? J : I);
2438 LIEPrev = LIENext;
2439 }
2440
2441 LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH);
2442 ExpandedIEChain = true;
2443 }
2444 }
2445
2446 return ExpandedIEChain;
2447 }
2448
getNumScalarElements(Type * Ty)2449 static unsigned getNumScalarElements(Type *Ty) {
2450 if (VectorType *VecTy = dyn_cast<VectorType>(Ty))
2451 return VecTy->getNumElements();
2452 return 1;
2453 }
2454
2455 // Returns the value to be used as the specified operand of the vector
2456 // instruction that fuses I with J.
getReplacementInput(LLVMContext & Context,Instruction * I,Instruction * J,unsigned o,bool IBeforeJ)2457 Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I,
2458 Instruction *J, unsigned o, bool IBeforeJ) {
2459 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
2460 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
2461
2462 // Compute the fused vector type for this operand
2463 Type *ArgTypeI = I->getOperand(o)->getType();
2464 Type *ArgTypeJ = J->getOperand(o)->getType();
2465 VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2466
2467 Instruction *L = I, *H = J;
2468 Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ;
2469
2470 unsigned numElemL = getNumScalarElements(ArgTypeL);
2471 unsigned numElemH = getNumScalarElements(ArgTypeH);
2472
2473 Value *LOp = L->getOperand(o);
2474 Value *HOp = H->getOperand(o);
2475 unsigned numElem = VArgType->getNumElements();
2476
2477 // First, we check if we can reuse the "original" vector outputs (if these
2478 // exist). We might need a shuffle.
2479 ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp);
2480 ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp);
2481 ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp);
2482 ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp);
2483
2484 // FIXME: If we're fusing shuffle instructions, then we can't apply this
2485 // optimization. The input vectors to the shuffle might be a different
2486 // length from the shuffle outputs. Unfortunately, the replacement
2487 // shuffle mask has already been formed, and the mask entries are sensitive
2488 // to the sizes of the inputs.
2489 bool IsSizeChangeShuffle =
2490 isa<ShuffleVectorInst>(L) &&
2491 (LOp->getType() != L->getType() || HOp->getType() != H->getType());
2492
2493 if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) {
2494 // We can have at most two unique vector inputs.
2495 bool CanUseInputs = true;
2496 Value *I1, *I2 = nullptr;
2497 if (LEE) {
2498 I1 = LEE->getOperand(0);
2499 } else {
2500 I1 = LSV->getOperand(0);
2501 I2 = LSV->getOperand(1);
2502 if (I2 == I1 || isa<UndefValue>(I2))
2503 I2 = nullptr;
2504 }
2505
2506 if (HEE) {
2507 Value *I3 = HEE->getOperand(0);
2508 if (!I2 && I3 != I1)
2509 I2 = I3;
2510 else if (I3 != I1 && I3 != I2)
2511 CanUseInputs = false;
2512 } else {
2513 Value *I3 = HSV->getOperand(0);
2514 if (!I2 && I3 != I1)
2515 I2 = I3;
2516 else if (I3 != I1 && I3 != I2)
2517 CanUseInputs = false;
2518
2519 if (CanUseInputs) {
2520 Value *I4 = HSV->getOperand(1);
2521 if (!isa<UndefValue>(I4)) {
2522 if (!I2 && I4 != I1)
2523 I2 = I4;
2524 else if (I4 != I1 && I4 != I2)
2525 CanUseInputs = false;
2526 }
2527 }
2528 }
2529
2530 if (CanUseInputs) {
2531 unsigned LOpElem =
2532 cast<Instruction>(LOp)->getOperand(0)->getType()
2533 ->getVectorNumElements();
2534
2535 unsigned HOpElem =
2536 cast<Instruction>(HOp)->getOperand(0)->getType()
2537 ->getVectorNumElements();
2538
2539 // We have one or two input vectors. We need to map each index of the
2540 // operands to the index of the original vector.
2541 SmallVector<std::pair<int, int>, 8> II(numElem);
2542 for (unsigned i = 0; i < numElemL; ++i) {
2543 int Idx, INum;
2544 if (LEE) {
2545 Idx =
2546 cast<ConstantInt>(LEE->getOperand(1))->getSExtValue();
2547 INum = LEE->getOperand(0) == I1 ? 0 : 1;
2548 } else {
2549 Idx = LSV->getMaskValue(i);
2550 if (Idx < (int) LOpElem) {
2551 INum = LSV->getOperand(0) == I1 ? 0 : 1;
2552 } else {
2553 Idx -= LOpElem;
2554 INum = LSV->getOperand(1) == I1 ? 0 : 1;
2555 }
2556 }
2557
2558 II[i] = std::pair<int, int>(Idx, INum);
2559 }
2560 for (unsigned i = 0; i < numElemH; ++i) {
2561 int Idx, INum;
2562 if (HEE) {
2563 Idx =
2564 cast<ConstantInt>(HEE->getOperand(1))->getSExtValue();
2565 INum = HEE->getOperand(0) == I1 ? 0 : 1;
2566 } else {
2567 Idx = HSV->getMaskValue(i);
2568 if (Idx < (int) HOpElem) {
2569 INum = HSV->getOperand(0) == I1 ? 0 : 1;
2570 } else {
2571 Idx -= HOpElem;
2572 INum = HSV->getOperand(1) == I1 ? 0 : 1;
2573 }
2574 }
2575
2576 II[i + numElemL] = std::pair<int, int>(Idx, INum);
2577 }
2578
2579 // We now have an array which tells us from which index of which
2580 // input vector each element of the operand comes.
2581 VectorType *I1T = cast<VectorType>(I1->getType());
2582 unsigned I1Elem = I1T->getNumElements();
2583
2584 if (!I2) {
2585 // In this case there is only one underlying vector input. Check for
2586 // the trivial case where we can use the input directly.
2587 if (I1Elem == numElem) {
2588 bool ElemInOrder = true;
2589 for (unsigned i = 0; i < numElem; ++i) {
2590 if (II[i].first != (int) i && II[i].first != -1) {
2591 ElemInOrder = false;
2592 break;
2593 }
2594 }
2595
2596 if (ElemInOrder)
2597 return I1;
2598 }
2599
2600 // A shuffle is needed.
2601 std::vector<Constant *> Mask(numElem);
2602 for (unsigned i = 0; i < numElem; ++i) {
2603 int Idx = II[i].first;
2604 if (Idx == -1)
2605 Mask[i] = UndefValue::get(Type::getInt32Ty(Context));
2606 else
2607 Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2608 }
2609
2610 Instruction *S =
2611 new ShuffleVectorInst(I1, UndefValue::get(I1T),
2612 ConstantVector::get(Mask),
2613 getReplacementName(IBeforeJ ? I : J,
2614 true, o));
2615 S->insertBefore(IBeforeJ ? J : I);
2616 return S;
2617 }
2618
2619 VectorType *I2T = cast<VectorType>(I2->getType());
2620 unsigned I2Elem = I2T->getNumElements();
2621
2622 // This input comes from two distinct vectors. The first step is to
2623 // make sure that both vectors are the same length. If not, the
2624 // smaller one will need to grow before they can be shuffled together.
2625 if (I1Elem < I2Elem) {
2626 std::vector<Constant *> Mask(I2Elem);
2627 unsigned v = 0;
2628 for (; v < I1Elem; ++v)
2629 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2630 for (; v < I2Elem; ++v)
2631 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2632
2633 Instruction *NewI1 =
2634 new ShuffleVectorInst(I1, UndefValue::get(I1T),
2635 ConstantVector::get(Mask),
2636 getReplacementName(IBeforeJ ? I : J,
2637 true, o, 1));
2638 NewI1->insertBefore(IBeforeJ ? J : I);
2639 I1 = NewI1;
2640 I1Elem = I2Elem;
2641 } else if (I1Elem > I2Elem) {
2642 std::vector<Constant *> Mask(I1Elem);
2643 unsigned v = 0;
2644 for (; v < I2Elem; ++v)
2645 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2646 for (; v < I1Elem; ++v)
2647 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2648
2649 Instruction *NewI2 =
2650 new ShuffleVectorInst(I2, UndefValue::get(I2T),
2651 ConstantVector::get(Mask),
2652 getReplacementName(IBeforeJ ? I : J,
2653 true, o, 1));
2654 NewI2->insertBefore(IBeforeJ ? J : I);
2655 I2 = NewI2;
2656 }
2657
2658 // Now that both I1 and I2 are the same length we can shuffle them
2659 // together (and use the result).
2660 std::vector<Constant *> Mask(numElem);
2661 for (unsigned v = 0; v < numElem; ++v) {
2662 if (II[v].first == -1) {
2663 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2664 } else {
2665 int Idx = II[v].first + II[v].second * I1Elem;
2666 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2667 }
2668 }
2669
2670 Instruction *NewOp =
2671 new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask),
2672 getReplacementName(IBeforeJ ? I : J, true, o));
2673 NewOp->insertBefore(IBeforeJ ? J : I);
2674 return NewOp;
2675 }
2676 }
2677
2678 Type *ArgType = ArgTypeL;
2679 if (numElemL < numElemH) {
2680 if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH,
2681 ArgTypeL, VArgType, IBeforeJ, 1)) {
2682 // This is another short-circuit case: we're combining a scalar into
2683 // a vector that is formed by an IE chain. We've just expanded the IE
2684 // chain, now insert the scalar and we're done.
2685
2686 Instruction *S = InsertElementInst::Create(HOp, LOp, CV0,
2687 getReplacementName(IBeforeJ ? I : J, true, o));
2688 S->insertBefore(IBeforeJ ? J : I);
2689 return S;
2690 } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL,
2691 ArgTypeH, IBeforeJ)) {
2692 // The two vector inputs to the shuffle must be the same length,
2693 // so extend the smaller vector to be the same length as the larger one.
2694 Instruction *NLOp;
2695 if (numElemL > 1) {
2696
2697 std::vector<Constant *> Mask(numElemH);
2698 unsigned v = 0;
2699 for (; v < numElemL; ++v)
2700 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2701 for (; v < numElemH; ++v)
2702 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2703
2704 NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL),
2705 ConstantVector::get(Mask),
2706 getReplacementName(IBeforeJ ? I : J,
2707 true, o, 1));
2708 } else {
2709 NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0,
2710 getReplacementName(IBeforeJ ? I : J,
2711 true, o, 1));
2712 }
2713
2714 NLOp->insertBefore(IBeforeJ ? J : I);
2715 LOp = NLOp;
2716 }
2717
2718 ArgType = ArgTypeH;
2719 } else if (numElemL > numElemH) {
2720 if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL,
2721 ArgTypeH, VArgType, IBeforeJ)) {
2722 Instruction *S =
2723 InsertElementInst::Create(LOp, HOp,
2724 ConstantInt::get(Type::getInt32Ty(Context),
2725 numElemL),
2726 getReplacementName(IBeforeJ ? I : J,
2727 true, o));
2728 S->insertBefore(IBeforeJ ? J : I);
2729 return S;
2730 } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH,
2731 ArgTypeL, IBeforeJ)) {
2732 Instruction *NHOp;
2733 if (numElemH > 1) {
2734 std::vector<Constant *> Mask(numElemL);
2735 unsigned v = 0;
2736 for (; v < numElemH; ++v)
2737 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2738 for (; v < numElemL; ++v)
2739 Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
2740
2741 NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH),
2742 ConstantVector::get(Mask),
2743 getReplacementName(IBeforeJ ? I : J,
2744 true, o, 1));
2745 } else {
2746 NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0,
2747 getReplacementName(IBeforeJ ? I : J,
2748 true, o, 1));
2749 }
2750
2751 NHOp->insertBefore(IBeforeJ ? J : I);
2752 HOp = NHOp;
2753 }
2754 }
2755
2756 if (ArgType->isVectorTy()) {
2757 unsigned numElem = VArgType->getVectorNumElements();
2758 std::vector<Constant*> Mask(numElem);
2759 for (unsigned v = 0; v < numElem; ++v) {
2760 unsigned Idx = v;
2761 // If the low vector was expanded, we need to skip the extra
2762 // undefined entries.
2763 if (v >= numElemL && numElemH > numElemL)
2764 Idx += (numElemH - numElemL);
2765 Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
2766 }
2767
2768 Instruction *BV = new ShuffleVectorInst(LOp, HOp,
2769 ConstantVector::get(Mask),
2770 getReplacementName(IBeforeJ ? I : J, true, o));
2771 BV->insertBefore(IBeforeJ ? J : I);
2772 return BV;
2773 }
2774
2775 Instruction *BV1 = InsertElementInst::Create(
2776 UndefValue::get(VArgType), LOp, CV0,
2777 getReplacementName(IBeforeJ ? I : J,
2778 true, o, 1));
2779 BV1->insertBefore(IBeforeJ ? J : I);
2780 Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1,
2781 getReplacementName(IBeforeJ ? I : J,
2782 true, o, 2));
2783 BV2->insertBefore(IBeforeJ ? J : I);
2784 return BV2;
2785 }
2786
2787 // This function creates an array of values that will be used as the inputs
2788 // to the vector instruction that fuses I with J.
getReplacementInputsForPair(LLVMContext & Context,Instruction * I,Instruction * J,SmallVectorImpl<Value * > & ReplacedOperands,bool IBeforeJ)2789 void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
2790 Instruction *I, Instruction *J,
2791 SmallVectorImpl<Value *> &ReplacedOperands,
2792 bool IBeforeJ) {
2793 unsigned NumOperands = I->getNumOperands();
2794
2795 for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
2796 // Iterate backward so that we look at the store pointer
2797 // first and know whether or not we need to flip the inputs.
2798
2799 if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) {
2800 // This is the pointer for a load/store instruction.
2801 ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o);
2802 continue;
2803 } else if (isa<CallInst>(I)) {
2804 Function *F = cast<CallInst>(I)->getCalledFunction();
2805 Intrinsic::ID IID = F->getIntrinsicID();
2806 if (o == NumOperands-1) {
2807 BasicBlock &BB = *I->getParent();
2808
2809 Module *M = BB.getParent()->getParent();
2810 Type *ArgTypeI = I->getType();
2811 Type *ArgTypeJ = J->getType();
2812 Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
2813
2814 ReplacedOperands[o] = Intrinsic::getDeclaration(M, IID, VArgType);
2815 continue;
2816 } else if ((IID == Intrinsic::powi || IID == Intrinsic::ctlz ||
2817 IID == Intrinsic::cttz) && o == 1) {
2818 // The second argument of powi/ctlz/cttz is a single integer/constant
2819 // and we've already checked that both arguments are equal.
2820 // As a result, we just keep I's second argument.
2821 ReplacedOperands[o] = I->getOperand(o);
2822 continue;
2823 }
2824 } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) {
2825 ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J);
2826 continue;
2827 }
2828
2829 ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ);
2830 }
2831 }
2832
2833 // This function creates two values that represent the outputs of the
2834 // original I and J instructions. These are generally vector shuffles
2835 // or extracts. In many cases, these will end up being unused and, thus,
2836 // eliminated by later passes.
replaceOutputsOfPair(LLVMContext & Context,Instruction * I,Instruction * J,Instruction * K,Instruction * & InsertionPt,Instruction * & K1,Instruction * & K2)2837 void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
2838 Instruction *J, Instruction *K,
2839 Instruction *&InsertionPt,
2840 Instruction *&K1, Instruction *&K2) {
2841 if (isa<StoreInst>(I))
2842 return;
2843
2844 Type *IType = I->getType();
2845 Type *JType = J->getType();
2846
2847 VectorType *VType = getVecTypeForPair(IType, JType);
2848 unsigned numElem = VType->getNumElements();
2849
2850 unsigned numElemI = getNumScalarElements(IType);
2851 unsigned numElemJ = getNumScalarElements(JType);
2852
2853 if (IType->isVectorTy()) {
2854 std::vector<Constant *> Mask1(numElemI), Mask2(numElemI);
2855 for (unsigned v = 0; v < numElemI; ++v) {
2856 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2857 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ + v);
2858 }
2859
2860 K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
2861 ConstantVector::get(Mask1),
2862 getReplacementName(K, false, 1));
2863 } else {
2864 Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
2865 K1 = ExtractElementInst::Create(K, CV0, getReplacementName(K, false, 1));
2866 }
2867
2868 if (JType->isVectorTy()) {
2869 std::vector<Constant *> Mask1(numElemJ), Mask2(numElemJ);
2870 for (unsigned v = 0; v < numElemJ; ++v) {
2871 Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
2872 Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI + v);
2873 }
2874
2875 K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
2876 ConstantVector::get(Mask2),
2877 getReplacementName(K, false, 2));
2878 } else {
2879 Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem - 1);
2880 K2 = ExtractElementInst::Create(K, CV1, getReplacementName(K, false, 2));
2881 }
2882
2883 K1->insertAfter(K);
2884 K2->insertAfter(K1);
2885 InsertionPt = K2;
2886 }
2887
2888 // Move all uses of the function I (including pairing-induced uses) after J.
canMoveUsesOfIAfterJ(BasicBlock & BB,DenseSet<ValuePair> & LoadMoveSetPairs,Instruction * I,Instruction * J)2889 bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB,
2890 DenseSet<ValuePair> &LoadMoveSetPairs,
2891 Instruction *I, Instruction *J) {
2892 // Skip to the first instruction past I.
2893 BasicBlock::iterator L = std::next(BasicBlock::iterator(I));
2894
2895 DenseSet<Value *> Users;
2896 AliasSetTracker WriteSet(*AA);
2897 if (I->mayWriteToMemory()) WriteSet.add(I);
2898
2899 for (; cast<Instruction>(L) != J; ++L)
2900 (void)trackUsesOfI(Users, WriteSet, I, &*L, true, &LoadMoveSetPairs);
2901
2902 assert(cast<Instruction>(L) == J &&
2903 "Tracking has not proceeded far enough to check for dependencies");
2904 // If J is now in the use set of I, then trackUsesOfI will return true
2905 // and we have a dependency cycle (and the fusing operation must abort).
2906 return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSetPairs);
2907 }
2908
2909 // Move all uses of the function I (including pairing-induced uses) after J.
moveUsesOfIAfterJ(BasicBlock & BB,DenseSet<ValuePair> & LoadMoveSetPairs,Instruction * & InsertionPt,Instruction * I,Instruction * J)2910 void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB,
2911 DenseSet<ValuePair> &LoadMoveSetPairs,
2912 Instruction *&InsertionPt,
2913 Instruction *I, Instruction *J) {
2914 // Skip to the first instruction past I.
2915 BasicBlock::iterator L = std::next(BasicBlock::iterator(I));
2916
2917 DenseSet<Value *> Users;
2918 AliasSetTracker WriteSet(*AA);
2919 if (I->mayWriteToMemory()) WriteSet.add(I);
2920
2921 for (; cast<Instruction>(L) != J;) {
2922 if (trackUsesOfI(Users, WriteSet, I, &*L, true, &LoadMoveSetPairs)) {
2923 // Move this instruction
2924 Instruction *InstToMove = &*L++;
2925
2926 DEBUG(dbgs() << "BBV: moving: " << *InstToMove <<
2927 " to after " << *InsertionPt << "\n");
2928 InstToMove->removeFromParent();
2929 InstToMove->insertAfter(InsertionPt);
2930 InsertionPt = InstToMove;
2931 } else {
2932 ++L;
2933 }
2934 }
2935 }
2936
2937 // Collect all load instruction that are in the move set of a given first
2938 // pair member. These loads depend on the first instruction, I, and so need
2939 // to be moved after J (the second instruction) when the pair is fused.
collectPairLoadMoveSet(BasicBlock & BB,DenseMap<Value *,Value * > & ChosenPairs,DenseMap<Value *,std::vector<Value * >> & LoadMoveSet,DenseSet<ValuePair> & LoadMoveSetPairs,Instruction * I)2940 void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB,
2941 DenseMap<Value *, Value *> &ChosenPairs,
2942 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
2943 DenseSet<ValuePair> &LoadMoveSetPairs,
2944 Instruction *I) {
2945 // Skip to the first instruction past I.
2946 BasicBlock::iterator L = std::next(BasicBlock::iterator(I));
2947
2948 DenseSet<Value *> Users;
2949 AliasSetTracker WriteSet(*AA);
2950 if (I->mayWriteToMemory()) WriteSet.add(I);
2951
2952 // Note: We cannot end the loop when we reach J because J could be moved
2953 // farther down the use chain by another instruction pairing. Also, J
2954 // could be before I if this is an inverted input.
2955 for (BasicBlock::iterator E = BB.end(); L != E; ++L) {
2956 if (trackUsesOfI(Users, WriteSet, I, &*L)) {
2957 if (L->mayReadFromMemory()) {
2958 LoadMoveSet[&*L].push_back(I);
2959 LoadMoveSetPairs.insert(ValuePair(&*L, I));
2960 }
2961 }
2962 }
2963 }
2964
2965 // In cases where both load/stores and the computation of their pointers
2966 // are chosen for vectorization, we can end up in a situation where the
2967 // aliasing analysis starts returning different query results as the
2968 // process of fusing instruction pairs continues. Because the algorithm
2969 // relies on finding the same use dags here as were found earlier, we'll
2970 // need to precompute the necessary aliasing information here and then
2971 // manually update it during the fusion process.
collectLoadMoveSet(BasicBlock & BB,std::vector<Value * > & PairableInsts,DenseMap<Value *,Value * > & ChosenPairs,DenseMap<Value *,std::vector<Value * >> & LoadMoveSet,DenseSet<ValuePair> & LoadMoveSetPairs)2972 void BBVectorize::collectLoadMoveSet(BasicBlock &BB,
2973 std::vector<Value *> &PairableInsts,
2974 DenseMap<Value *, Value *> &ChosenPairs,
2975 DenseMap<Value *, std::vector<Value *> > &LoadMoveSet,
2976 DenseSet<ValuePair> &LoadMoveSetPairs) {
2977 for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
2978 PIE = PairableInsts.end(); PI != PIE; ++PI) {
2979 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI);
2980 if (P == ChosenPairs.end()) continue;
2981
2982 Instruction *I = cast<Instruction>(P->first);
2983 collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet,
2984 LoadMoveSetPairs, I);
2985 }
2986 }
2987
2988 // This function fuses the chosen instruction pairs into vector instructions,
2989 // taking care preserve any needed scalar outputs and, then, it reorders the
2990 // remaining instructions as needed (users of the first member of the pair
2991 // need to be moved to after the location of the second member of the pair
2992 // because the vector instruction is inserted in the location of the pair's
2993 // second member).
fuseChosenPairs(BasicBlock & BB,std::vector<Value * > & PairableInsts,DenseMap<Value *,Value * > & ChosenPairs,DenseSet<ValuePair> & FixedOrderPairs,DenseMap<VPPair,unsigned> & PairConnectionTypes,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairs,DenseMap<ValuePair,std::vector<ValuePair>> & ConnectedPairDeps)2994 void BBVectorize::fuseChosenPairs(BasicBlock &BB,
2995 std::vector<Value *> &PairableInsts,
2996 DenseMap<Value *, Value *> &ChosenPairs,
2997 DenseSet<ValuePair> &FixedOrderPairs,
2998 DenseMap<VPPair, unsigned> &PairConnectionTypes,
2999 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairs,
3000 DenseMap<ValuePair, std::vector<ValuePair> > &ConnectedPairDeps) {
3001 LLVMContext& Context = BB.getContext();
3002
3003 // During the vectorization process, the order of the pairs to be fused
3004 // could be flipped. So we'll add each pair, flipped, into the ChosenPairs
3005 // list. After a pair is fused, the flipped pair is removed from the list.
3006 DenseSet<ValuePair> FlippedPairs;
3007 for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(),
3008 E = ChosenPairs.end(); P != E; ++P)
3009 FlippedPairs.insert(ValuePair(P->second, P->first));
3010 for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(),
3011 E = FlippedPairs.end(); P != E; ++P)
3012 ChosenPairs.insert(*P);
3013
3014 DenseMap<Value *, std::vector<Value *> > LoadMoveSet;
3015 DenseSet<ValuePair> LoadMoveSetPairs;
3016 collectLoadMoveSet(BB, PairableInsts, ChosenPairs,
3017 LoadMoveSet, LoadMoveSetPairs);
3018
3019 DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n");
3020
3021 for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) {
3022 DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(&*PI);
3023 if (P == ChosenPairs.end()) {
3024 ++PI;
3025 continue;
3026 }
3027
3028 if (getDepthFactor(P->first) == 0) {
3029 // These instructions are not really fused, but are tracked as though
3030 // they are. Any case in which it would be interesting to fuse them
3031 // will be taken care of by InstCombine.
3032 --NumFusedOps;
3033 ++PI;
3034 continue;
3035 }
3036
3037 Instruction *I = cast<Instruction>(P->first),
3038 *J = cast<Instruction>(P->second);
3039
3040 DEBUG(dbgs() << "BBV: fusing: " << *I <<
3041 " <-> " << *J << "\n");
3042
3043 // Remove the pair and flipped pair from the list.
3044 DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second);
3045 assert(FP != ChosenPairs.end() && "Flipped pair not found in list");
3046 ChosenPairs.erase(FP);
3047 ChosenPairs.erase(P);
3048
3049 if (!canMoveUsesOfIAfterJ(BB, LoadMoveSetPairs, I, J)) {
3050 DEBUG(dbgs() << "BBV: fusion of: " << *I <<
3051 " <-> " << *J <<
3052 " aborted because of non-trivial dependency cycle\n");
3053 --NumFusedOps;
3054 ++PI;
3055 continue;
3056 }
3057
3058 // If the pair must have the other order, then flip it.
3059 bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I));
3060 if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) {
3061 // This pair does not have a fixed order, and so we might want to
3062 // flip it if that will yield fewer shuffles. We count the number
3063 // of dependencies connected via swaps, and those directly connected,
3064 // and flip the order if the number of swaps is greater.
3065 bool OrigOrder = true;
3066 DenseMap<ValuePair, std::vector<ValuePair> >::iterator IJ =
3067 ConnectedPairDeps.find(ValuePair(I, J));
3068 if (IJ == ConnectedPairDeps.end()) {
3069 IJ = ConnectedPairDeps.find(ValuePair(J, I));
3070 OrigOrder = false;
3071 }
3072
3073 if (IJ != ConnectedPairDeps.end()) {
3074 unsigned NumDepsDirect = 0, NumDepsSwap = 0;
3075 for (std::vector<ValuePair>::iterator T = IJ->second.begin(),
3076 TE = IJ->second.end(); T != TE; ++T) {
3077 VPPair Q(IJ->first, *T);
3078 DenseMap<VPPair, unsigned>::iterator R =
3079 PairConnectionTypes.find(VPPair(Q.second, Q.first));
3080 assert(R != PairConnectionTypes.end() &&
3081 "Cannot find pair connection type");
3082 if (R->second == PairConnectionDirect)
3083 ++NumDepsDirect;
3084 else if (R->second == PairConnectionSwap)
3085 ++NumDepsSwap;
3086 }
3087
3088 if (!OrigOrder)
3089 std::swap(NumDepsDirect, NumDepsSwap);
3090
3091 if (NumDepsSwap > NumDepsDirect) {
3092 FlipPairOrder = true;
3093 DEBUG(dbgs() << "BBV: reordering pair: " << *I <<
3094 " <-> " << *J << "\n");
3095 }
3096 }
3097 }
3098
3099 Instruction *L = I, *H = J;
3100 if (FlipPairOrder)
3101 std::swap(H, L);
3102
3103 // If the pair being fused uses the opposite order from that in the pair
3104 // connection map, then we need to flip the types.
3105 DenseMap<ValuePair, std::vector<ValuePair> >::iterator HL =
3106 ConnectedPairs.find(ValuePair(H, L));
3107 if (HL != ConnectedPairs.end())
3108 for (std::vector<ValuePair>::iterator T = HL->second.begin(),
3109 TE = HL->second.end(); T != TE; ++T) {
3110 VPPair Q(HL->first, *T);
3111 DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(Q);
3112 assert(R != PairConnectionTypes.end() &&
3113 "Cannot find pair connection type");
3114 if (R->second == PairConnectionDirect)
3115 R->second = PairConnectionSwap;
3116 else if (R->second == PairConnectionSwap)
3117 R->second = PairConnectionDirect;
3118 }
3119
3120 bool LBeforeH = !FlipPairOrder;
3121 unsigned NumOperands = I->getNumOperands();
3122 SmallVector<Value *, 3> ReplacedOperands(NumOperands);
3123 getReplacementInputsForPair(Context, L, H, ReplacedOperands,
3124 LBeforeH);
3125
3126 // Make a copy of the original operation, change its type to the vector
3127 // type and replace its operands with the vector operands.
3128 Instruction *K = L->clone();
3129 if (L->hasName())
3130 K->takeName(L);
3131 else if (H->hasName())
3132 K->takeName(H);
3133
3134 if (auto CS = CallSite(K)) {
3135 SmallVector<Type *, 3> Tys;
3136 FunctionType *Old = CS.getFunctionType();
3137 unsigned NumOld = Old->getNumParams();
3138 assert(NumOld <= ReplacedOperands.size());
3139 for (unsigned i = 0; i != NumOld; ++i)
3140 Tys.push_back(ReplacedOperands[i]->getType());
3141 CS.mutateFunctionType(
3142 FunctionType::get(getVecTypeForPair(L->getType(), H->getType()),
3143 Tys, Old->isVarArg()));
3144 } else if (!isa<StoreInst>(K))
3145 K->mutateType(getVecTypeForPair(L->getType(), H->getType()));
3146
3147 unsigned KnownIDs[] = {LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
3148 LLVMContext::MD_noalias, LLVMContext::MD_fpmath,
3149 LLVMContext::MD_invariant_group};
3150 combineMetadata(K, H, KnownIDs);
3151 K->intersectOptionalDataWith(H);
3152
3153 for (unsigned o = 0; o < NumOperands; ++o)
3154 K->setOperand(o, ReplacedOperands[o]);
3155
3156 K->insertAfter(J);
3157
3158 // Instruction insertion point:
3159 Instruction *InsertionPt = K;
3160 Instruction *K1 = nullptr, *K2 = nullptr;
3161 replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2);
3162
3163 // The use dag of the first original instruction must be moved to after
3164 // the location of the second instruction. The entire use dag of the
3165 // first instruction is disjoint from the input dag of the second
3166 // (by definition), and so commutes with it.
3167
3168 moveUsesOfIAfterJ(BB, LoadMoveSetPairs, InsertionPt, I, J);
3169
3170 if (!isa<StoreInst>(I)) {
3171 L->replaceAllUsesWith(K1);
3172 H->replaceAllUsesWith(K2);
3173 }
3174
3175 // Instructions that may read from memory may be in the load move set.
3176 // Once an instruction is fused, we no longer need its move set, and so
3177 // the values of the map never need to be updated. However, when a load
3178 // is fused, we need to merge the entries from both instructions in the
3179 // pair in case those instructions were in the move set of some other
3180 // yet-to-be-fused pair. The loads in question are the keys of the map.
3181 if (I->mayReadFromMemory()) {
3182 std::vector<ValuePair> NewSetMembers;
3183 DenseMap<Value *, std::vector<Value *> >::iterator II =
3184 LoadMoveSet.find(I);
3185 if (II != LoadMoveSet.end())
3186 for (std::vector<Value *>::iterator N = II->second.begin(),
3187 NE = II->second.end(); N != NE; ++N)
3188 NewSetMembers.push_back(ValuePair(K, *N));
3189 DenseMap<Value *, std::vector<Value *> >::iterator JJ =
3190 LoadMoveSet.find(J);
3191 if (JJ != LoadMoveSet.end())
3192 for (std::vector<Value *>::iterator N = JJ->second.begin(),
3193 NE = JJ->second.end(); N != NE; ++N)
3194 NewSetMembers.push_back(ValuePair(K, *N));
3195 for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(),
3196 AE = NewSetMembers.end(); A != AE; ++A) {
3197 LoadMoveSet[A->first].push_back(A->second);
3198 LoadMoveSetPairs.insert(*A);
3199 }
3200 }
3201
3202 // Before removing I, set the iterator to the next instruction.
3203 PI = std::next(BasicBlock::iterator(I));
3204 if (cast<Instruction>(PI) == J)
3205 ++PI;
3206
3207 SE->forgetValue(I);
3208 SE->forgetValue(J);
3209 I->eraseFromParent();
3210 J->eraseFromParent();
3211
3212 DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" <<
3213 BB << "\n");
3214 }
3215
3216 DEBUG(dbgs() << "BBV: final: \n" << BB << "\n");
3217 }
3218 }
3219
3220 char BBVectorize::ID = 0;
3221 static const char bb_vectorize_name[] = "Basic-Block Vectorization";
INITIALIZE_PASS_BEGIN(BBVectorize,BBV_NAME,bb_vectorize_name,false,false)3222 INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
3223 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
3224 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
3225 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
3226 INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
3227 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
3228 INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
3229 INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
3230 INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
3231 INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
3232
3233 BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) {
3234 return new BBVectorize(C);
3235 }
3236
3237 bool
vectorizeBasicBlock(Pass * P,BasicBlock & BB,const VectorizeConfig & C)3238 llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) {
3239 BBVectorize BBVectorizer(P, *BB.getParent(), C);
3240 return BBVectorizer.vectorizeBB(BB);
3241 }
3242
3243 //===----------------------------------------------------------------------===//
VectorizeConfig()3244 VectorizeConfig::VectorizeConfig() {
3245 VectorBits = ::VectorBits;
3246 VectorizeBools = !::NoBools;
3247 VectorizeInts = !::NoInts;
3248 VectorizeFloats = !::NoFloats;
3249 VectorizePointers = !::NoPointers;
3250 VectorizeCasts = !::NoCasts;
3251 VectorizeMath = !::NoMath;
3252 VectorizeBitManipulations = !::NoBitManipulation;
3253 VectorizeFMA = !::NoFMA;
3254 VectorizeSelect = !::NoSelect;
3255 VectorizeCmp = !::NoCmp;
3256 VectorizeGEP = !::NoGEP;
3257 VectorizeMemOps = !::NoMemOps;
3258 AlignedOnly = ::AlignedOnly;
3259 ReqChainDepth= ::ReqChainDepth;
3260 SearchLimit = ::SearchLimit;
3261 MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck;
3262 SplatBreaksChain = ::SplatBreaksChain;
3263 MaxInsts = ::MaxInsts;
3264 MaxPairs = ::MaxPairs;
3265 MaxIter = ::MaxIter;
3266 Pow2LenOnly = ::Pow2LenOnly;
3267 NoMemOpBoost = ::NoMemOpBoost;
3268 FastDep = ::FastDep;
3269 }
3270