File: | lib/Transforms/Scalar/LoopStrengthReduce.cpp |
Location: | line 4691, column 22 |
Description: | Called C++ object pointer is null |
1 | //===- LoopStrengthReduce.cpp - Strength Reduce IVs in Loops --------------===// | |||
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 transformation analyzes and transforms the induction variables (and | |||
11 | // computations derived from them) into forms suitable for efficient execution | |||
12 | // on the target. | |||
13 | // | |||
14 | // This pass performs a strength reduction on array references inside loops that | |||
15 | // have as one or more of their components the loop induction variable, it | |||
16 | // rewrites expressions to take advantage of scaled-index addressing modes | |||
17 | // available on the target, and it performs a variety of other optimizations | |||
18 | // related to loop induction variables. | |||
19 | // | |||
20 | // Terminology note: this code has a lot of handling for "post-increment" or | |||
21 | // "post-inc" users. This is not talking about post-increment addressing modes; | |||
22 | // it is instead talking about code like this: | |||
23 | // | |||
24 | // %i = phi [ 0, %entry ], [ %i.next, %latch ] | |||
25 | // ... | |||
26 | // %i.next = add %i, 1 | |||
27 | // %c = icmp eq %i.next, %n | |||
28 | // | |||
29 | // The SCEV for %i is {0,+,1}<%L>. The SCEV for %i.next is {1,+,1}<%L>, however | |||
30 | // it's useful to think about these as the same register, with some uses using | |||
31 | // the value of the register before the add and some using it after. In this | |||
32 | // example, the icmp is a post-increment user, since it uses %i.next, which is | |||
33 | // the value of the induction variable after the increment. The other common | |||
34 | // case of post-increment users is users outside the loop. | |||
35 | // | |||
36 | // TODO: More sophistication in the way Formulae are generated and filtered. | |||
37 | // | |||
38 | // TODO: Handle multiple loops at a time. | |||
39 | // | |||
40 | // TODO: Should the addressing mode BaseGV be changed to a ConstantExpr instead | |||
41 | // of a GlobalValue? | |||
42 | // | |||
43 | // TODO: When truncation is free, truncate ICmp users' operands to make it a | |||
44 | // smaller encoding (on x86 at least). | |||
45 | // | |||
46 | // TODO: When a negated register is used by an add (such as in a list of | |||
47 | // multiple base registers, or as the increment expression in an addrec), | |||
48 | // we may not actually need both reg and (-1 * reg) in registers; the | |||
49 | // negation can be implemented by using a sub instead of an add. The | |||
50 | // lack of support for taking this into consideration when making | |||
51 | // register pressure decisions is partly worked around by the "Special" | |||
52 | // use kind. | |||
53 | // | |||
54 | //===----------------------------------------------------------------------===// | |||
55 | ||||
56 | #include "llvm/Transforms/Scalar.h" | |||
57 | #include "llvm/ADT/DenseSet.h" | |||
58 | #include "llvm/ADT/Hashing.h" | |||
59 | #include "llvm/ADT/STLExtras.h" | |||
60 | #include "llvm/ADT/SetVector.h" | |||
61 | #include "llvm/ADT/SmallBitVector.h" | |||
62 | #include "llvm/Analysis/IVUsers.h" | |||
63 | #include "llvm/Analysis/LoopPass.h" | |||
64 | #include "llvm/Analysis/ScalarEvolutionExpander.h" | |||
65 | #include "llvm/Analysis/TargetTransformInfo.h" | |||
66 | #include "llvm/IR/Constants.h" | |||
67 | #include "llvm/IR/DerivedTypes.h" | |||
68 | #include "llvm/IR/Dominators.h" | |||
69 | #include "llvm/IR/Instructions.h" | |||
70 | #include "llvm/IR/IntrinsicInst.h" | |||
71 | #include "llvm/IR/Module.h" | |||
72 | #include "llvm/IR/ValueHandle.h" | |||
73 | #include "llvm/Support/CommandLine.h" | |||
74 | #include "llvm/Support/Debug.h" | |||
75 | #include "llvm/Support/raw_ostream.h" | |||
76 | #include "llvm/Transforms/Utils/BasicBlockUtils.h" | |||
77 | #include "llvm/Transforms/Utils/Local.h" | |||
78 | #include <algorithm> | |||
79 | using namespace llvm; | |||
80 | ||||
81 | #define DEBUG_TYPE"loop-reduce" "loop-reduce" | |||
82 | ||||
83 | /// MaxIVUsers is an arbitrary threshold that provides an early opportunitiy for | |||
84 | /// bail out. This threshold is far beyond the number of users that LSR can | |||
85 | /// conceivably solve, so it should not affect generated code, but catches the | |||
86 | /// worst cases before LSR burns too much compile time and stack space. | |||
87 | static const unsigned MaxIVUsers = 200; | |||
88 | ||||
89 | // Temporary flag to cleanup congruent phis after LSR phi expansion. | |||
90 | // It's currently disabled until we can determine whether it's truly useful or | |||
91 | // not. The flag should be removed after the v3.0 release. | |||
92 | // This is now needed for ivchains. | |||
93 | static cl::opt<bool> EnablePhiElim( | |||
94 | "enable-lsr-phielim", cl::Hidden, cl::init(true), | |||
95 | cl::desc("Enable LSR phi elimination")); | |||
96 | ||||
97 | #ifndef NDEBUG | |||
98 | // Stress test IV chain generation. | |||
99 | static cl::opt<bool> StressIVChain( | |||
100 | "stress-ivchain", cl::Hidden, cl::init(false), | |||
101 | cl::desc("Stress test LSR IV chains")); | |||
102 | #else | |||
103 | static bool StressIVChain = false; | |||
104 | #endif | |||
105 | ||||
106 | namespace { | |||
107 | ||||
108 | /// RegSortData - This class holds data which is used to order reuse candidates. | |||
109 | class RegSortData { | |||
110 | public: | |||
111 | /// UsedByIndices - This represents the set of LSRUse indices which reference | |||
112 | /// a particular register. | |||
113 | SmallBitVector UsedByIndices; | |||
114 | ||||
115 | void print(raw_ostream &OS) const; | |||
116 | void dump() const; | |||
117 | }; | |||
118 | ||||
119 | } | |||
120 | ||||
121 | void RegSortData::print(raw_ostream &OS) const { | |||
122 | OS << "[NumUses=" << UsedByIndices.count() << ']'; | |||
123 | } | |||
124 | ||||
125 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | |||
126 | void RegSortData::dump() const { | |||
127 | print(errs()); errs() << '\n'; | |||
128 | } | |||
129 | #endif | |||
130 | ||||
131 | namespace { | |||
132 | ||||
133 | /// RegUseTracker - Map register candidates to information about how they are | |||
134 | /// used. | |||
135 | class RegUseTracker { | |||
136 | typedef DenseMap<const SCEV *, RegSortData> RegUsesTy; | |||
137 | ||||
138 | RegUsesTy RegUsesMap; | |||
139 | SmallVector<const SCEV *, 16> RegSequence; | |||
140 | ||||
141 | public: | |||
142 | void CountRegister(const SCEV *Reg, size_t LUIdx); | |||
143 | void DropRegister(const SCEV *Reg, size_t LUIdx); | |||
144 | void SwapAndDropUse(size_t LUIdx, size_t LastLUIdx); | |||
145 | ||||
146 | bool isRegUsedByUsesOtherThan(const SCEV *Reg, size_t LUIdx) const; | |||
147 | ||||
148 | const SmallBitVector &getUsedByIndices(const SCEV *Reg) const; | |||
149 | ||||
150 | void clear(); | |||
151 | ||||
152 | typedef SmallVectorImpl<const SCEV *>::iterator iterator; | |||
153 | typedef SmallVectorImpl<const SCEV *>::const_iterator const_iterator; | |||
154 | iterator begin() { return RegSequence.begin(); } | |||
155 | iterator end() { return RegSequence.end(); } | |||
156 | const_iterator begin() const { return RegSequence.begin(); } | |||
157 | const_iterator end() const { return RegSequence.end(); } | |||
158 | }; | |||
159 | ||||
160 | } | |||
161 | ||||
162 | void | |||
163 | RegUseTracker::CountRegister(const SCEV *Reg, size_t LUIdx) { | |||
164 | std::pair<RegUsesTy::iterator, bool> Pair = | |||
165 | RegUsesMap.insert(std::make_pair(Reg, RegSortData())); | |||
166 | RegSortData &RSD = Pair.first->second; | |||
167 | if (Pair.second) | |||
168 | RegSequence.push_back(Reg); | |||
169 | RSD.UsedByIndices.resize(std::max(RSD.UsedByIndices.size(), LUIdx + 1)); | |||
170 | RSD.UsedByIndices.set(LUIdx); | |||
171 | } | |||
172 | ||||
173 | void | |||
174 | RegUseTracker::DropRegister(const SCEV *Reg, size_t LUIdx) { | |||
175 | RegUsesTy::iterator It = RegUsesMap.find(Reg); | |||
176 | assert(It != RegUsesMap.end())((It != RegUsesMap.end()) ? static_cast<void> (0) : __assert_fail ("It != RegUsesMap.end()", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 176, __PRETTY_FUNCTION__)); | |||
177 | RegSortData &RSD = It->second; | |||
178 | assert(RSD.UsedByIndices.size() > LUIdx)((RSD.UsedByIndices.size() > LUIdx) ? static_cast<void> (0) : __assert_fail ("RSD.UsedByIndices.size() > LUIdx", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 178, __PRETTY_FUNCTION__)); | |||
179 | RSD.UsedByIndices.reset(LUIdx); | |||
180 | } | |||
181 | ||||
182 | void | |||
183 | RegUseTracker::SwapAndDropUse(size_t LUIdx, size_t LastLUIdx) { | |||
184 | assert(LUIdx <= LastLUIdx)((LUIdx <= LastLUIdx) ? static_cast<void> (0) : __assert_fail ("LUIdx <= LastLUIdx", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 184, __PRETTY_FUNCTION__)); | |||
185 | ||||
186 | // Update RegUses. The data structure is not optimized for this purpose; | |||
187 | // we must iterate through it and update each of the bit vectors. | |||
188 | for (auto &Pair : RegUsesMap) { | |||
189 | SmallBitVector &UsedByIndices = Pair.second.UsedByIndices; | |||
190 | if (LUIdx < UsedByIndices.size()) | |||
191 | UsedByIndices[LUIdx] = | |||
192 | LastLUIdx < UsedByIndices.size() ? UsedByIndices[LastLUIdx] : 0; | |||
193 | UsedByIndices.resize(std::min(UsedByIndices.size(), LastLUIdx)); | |||
194 | } | |||
195 | } | |||
196 | ||||
197 | bool | |||
198 | RegUseTracker::isRegUsedByUsesOtherThan(const SCEV *Reg, size_t LUIdx) const { | |||
199 | RegUsesTy::const_iterator I = RegUsesMap.find(Reg); | |||
200 | if (I == RegUsesMap.end()) | |||
201 | return false; | |||
202 | const SmallBitVector &UsedByIndices = I->second.UsedByIndices; | |||
203 | int i = UsedByIndices.find_first(); | |||
204 | if (i == -1) return false; | |||
205 | if ((size_t)i != LUIdx) return true; | |||
206 | return UsedByIndices.find_next(i) != -1; | |||
207 | } | |||
208 | ||||
209 | const SmallBitVector &RegUseTracker::getUsedByIndices(const SCEV *Reg) const { | |||
210 | RegUsesTy::const_iterator I = RegUsesMap.find(Reg); | |||
211 | assert(I != RegUsesMap.end() && "Unknown register!")((I != RegUsesMap.end() && "Unknown register!") ? static_cast <void> (0) : __assert_fail ("I != RegUsesMap.end() && \"Unknown register!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 211, __PRETTY_FUNCTION__)); | |||
212 | return I->second.UsedByIndices; | |||
213 | } | |||
214 | ||||
215 | void RegUseTracker::clear() { | |||
216 | RegUsesMap.clear(); | |||
217 | RegSequence.clear(); | |||
218 | } | |||
219 | ||||
220 | namespace { | |||
221 | ||||
222 | /// Formula - This class holds information that describes a formula for | |||
223 | /// computing satisfying a use. It may include broken-out immediates and scaled | |||
224 | /// registers. | |||
225 | struct Formula { | |||
226 | /// Global base address used for complex addressing. | |||
227 | GlobalValue *BaseGV; | |||
228 | ||||
229 | /// Base offset for complex addressing. | |||
230 | int64_t BaseOffset; | |||
231 | ||||
232 | /// Whether any complex addressing has a base register. | |||
233 | bool HasBaseReg; | |||
234 | ||||
235 | /// The scale of any complex addressing. | |||
236 | int64_t Scale; | |||
237 | ||||
238 | /// BaseRegs - The list of "base" registers for this use. When this is | |||
239 | /// non-empty. The canonical representation of a formula is | |||
240 | /// 1. BaseRegs.size > 1 implies ScaledReg != NULL and | |||
241 | /// 2. ScaledReg != NULL implies Scale != 1 || !BaseRegs.empty(). | |||
242 | /// #1 enforces that the scaled register is always used when at least two | |||
243 | /// registers are needed by the formula: e.g., reg1 + reg2 is reg1 + 1 * reg2. | |||
244 | /// #2 enforces that 1 * reg is reg. | |||
245 | /// This invariant can be temporarly broken while building a formula. | |||
246 | /// However, every formula inserted into the LSRInstance must be in canonical | |||
247 | /// form. | |||
248 | SmallVector<const SCEV *, 4> BaseRegs; | |||
249 | ||||
250 | /// ScaledReg - The 'scaled' register for this use. This should be non-null | |||
251 | /// when Scale is not zero. | |||
252 | const SCEV *ScaledReg; | |||
253 | ||||
254 | /// UnfoldedOffset - An additional constant offset which added near the | |||
255 | /// use. This requires a temporary register, but the offset itself can | |||
256 | /// live in an add immediate field rather than a register. | |||
257 | int64_t UnfoldedOffset; | |||
258 | ||||
259 | Formula() | |||
260 | : BaseGV(nullptr), BaseOffset(0), HasBaseReg(false), Scale(0), | |||
261 | ScaledReg(nullptr), UnfoldedOffset(0) {} | |||
262 | ||||
263 | void InitialMatch(const SCEV *S, Loop *L, ScalarEvolution &SE); | |||
264 | ||||
265 | bool isCanonical() const; | |||
266 | ||||
267 | void Canonicalize(); | |||
268 | ||||
269 | bool Unscale(); | |||
270 | ||||
271 | size_t getNumRegs() const; | |||
272 | Type *getType() const; | |||
273 | ||||
274 | void DeleteBaseReg(const SCEV *&S); | |||
275 | ||||
276 | bool referencesReg(const SCEV *S) const; | |||
277 | bool hasRegsUsedByUsesOtherThan(size_t LUIdx, | |||
278 | const RegUseTracker &RegUses) const; | |||
279 | ||||
280 | void print(raw_ostream &OS) const; | |||
281 | void dump() const; | |||
282 | }; | |||
283 | ||||
284 | } | |||
285 | ||||
286 | /// DoInitialMatch - Recursion helper for InitialMatch. | |||
287 | static void DoInitialMatch(const SCEV *S, Loop *L, | |||
288 | SmallVectorImpl<const SCEV *> &Good, | |||
289 | SmallVectorImpl<const SCEV *> &Bad, | |||
290 | ScalarEvolution &SE) { | |||
291 | // Collect expressions which properly dominate the loop header. | |||
292 | if (SE.properlyDominates(S, L->getHeader())) { | |||
293 | Good.push_back(S); | |||
294 | return; | |||
295 | } | |||
296 | ||||
297 | // Look at add operands. | |||
298 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | |||
299 | for (const SCEV *S : Add->operands()) | |||
300 | DoInitialMatch(S, L, Good, Bad, SE); | |||
301 | return; | |||
302 | } | |||
303 | ||||
304 | // Look at addrec operands. | |||
305 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) | |||
306 | if (!AR->getStart()->isZero()) { | |||
307 | DoInitialMatch(AR->getStart(), L, Good, Bad, SE); | |||
308 | DoInitialMatch(SE.getAddRecExpr(SE.getConstant(AR->getType(), 0), | |||
309 | AR->getStepRecurrence(SE), | |||
310 | // FIXME: AR->getNoWrapFlags() | |||
311 | AR->getLoop(), SCEV::FlagAnyWrap), | |||
312 | L, Good, Bad, SE); | |||
313 | return; | |||
314 | } | |||
315 | ||||
316 | // Handle a multiplication by -1 (negation) if it didn't fold. | |||
317 | if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) | |||
318 | if (Mul->getOperand(0)->isAllOnesValue()) { | |||
319 | SmallVector<const SCEV *, 4> Ops(Mul->op_begin()+1, Mul->op_end()); | |||
320 | const SCEV *NewMul = SE.getMulExpr(Ops); | |||
321 | ||||
322 | SmallVector<const SCEV *, 4> MyGood; | |||
323 | SmallVector<const SCEV *, 4> MyBad; | |||
324 | DoInitialMatch(NewMul, L, MyGood, MyBad, SE); | |||
325 | const SCEV *NegOne = SE.getSCEV(ConstantInt::getAllOnesValue( | |||
326 | SE.getEffectiveSCEVType(NewMul->getType()))); | |||
327 | for (const SCEV *S : MyGood) | |||
328 | Good.push_back(SE.getMulExpr(NegOne, S)); | |||
329 | for (const SCEV *S : MyBad) | |||
330 | Bad.push_back(SE.getMulExpr(NegOne, S)); | |||
331 | return; | |||
332 | } | |||
333 | ||||
334 | // Ok, we can't do anything interesting. Just stuff the whole thing into a | |||
335 | // register and hope for the best. | |||
336 | Bad.push_back(S); | |||
337 | } | |||
338 | ||||
339 | /// InitialMatch - Incorporate loop-variant parts of S into this Formula, | |||
340 | /// attempting to keep all loop-invariant and loop-computable values in a | |||
341 | /// single base register. | |||
342 | void Formula::InitialMatch(const SCEV *S, Loop *L, ScalarEvolution &SE) { | |||
343 | SmallVector<const SCEV *, 4> Good; | |||
344 | SmallVector<const SCEV *, 4> Bad; | |||
345 | DoInitialMatch(S, L, Good, Bad, SE); | |||
346 | if (!Good.empty()) { | |||
347 | const SCEV *Sum = SE.getAddExpr(Good); | |||
348 | if (!Sum->isZero()) | |||
349 | BaseRegs.push_back(Sum); | |||
350 | HasBaseReg = true; | |||
351 | } | |||
352 | if (!Bad.empty()) { | |||
353 | const SCEV *Sum = SE.getAddExpr(Bad); | |||
354 | if (!Sum->isZero()) | |||
355 | BaseRegs.push_back(Sum); | |||
356 | HasBaseReg = true; | |||
357 | } | |||
358 | Canonicalize(); | |||
359 | } | |||
360 | ||||
361 | /// \brief Check whether or not this formula statisfies the canonical | |||
362 | /// representation. | |||
363 | /// \see Formula::BaseRegs. | |||
364 | bool Formula::isCanonical() const { | |||
365 | if (ScaledReg) | |||
366 | return Scale != 1 || !BaseRegs.empty(); | |||
367 | return BaseRegs.size() <= 1; | |||
368 | } | |||
369 | ||||
370 | /// \brief Helper method to morph a formula into its canonical representation. | |||
371 | /// \see Formula::BaseRegs. | |||
372 | /// Every formula having more than one base register, must use the ScaledReg | |||
373 | /// field. Otherwise, we would have to do special cases everywhere in LSR | |||
374 | /// to treat reg1 + reg2 + ... the same way as reg1 + 1*reg2 + ... | |||
375 | /// On the other hand, 1*reg should be canonicalized into reg. | |||
376 | void Formula::Canonicalize() { | |||
377 | if (isCanonical()) | |||
378 | return; | |||
379 | // So far we did not need this case. This is easy to implement but it is | |||
380 | // useless to maintain dead code. Beside it could hurt compile time. | |||
381 | assert(!BaseRegs.empty() && "1*reg => reg, should not be needed.")((!BaseRegs.empty() && "1*reg => reg, should not be needed." ) ? static_cast<void> (0) : __assert_fail ("!BaseRegs.empty() && \"1*reg => reg, should not be needed.\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 381, __PRETTY_FUNCTION__)); | |||
382 | // Keep the invariant sum in BaseRegs and one of the variant sum in ScaledReg. | |||
383 | ScaledReg = BaseRegs.back(); | |||
384 | BaseRegs.pop_back(); | |||
385 | Scale = 1; | |||
386 | size_t BaseRegsSize = BaseRegs.size(); | |||
387 | size_t Try = 0; | |||
388 | // If ScaledReg is an invariant, try to find a variant expression. | |||
389 | while (Try < BaseRegsSize && !isa<SCEVAddRecExpr>(ScaledReg)) | |||
390 | std::swap(ScaledReg, BaseRegs[Try++]); | |||
391 | } | |||
392 | ||||
393 | /// \brief Get rid of the scale in the formula. | |||
394 | /// In other words, this method morphes reg1 + 1*reg2 into reg1 + reg2. | |||
395 | /// \return true if it was possible to get rid of the scale, false otherwise. | |||
396 | /// \note After this operation the formula may not be in the canonical form. | |||
397 | bool Formula::Unscale() { | |||
398 | if (Scale != 1) | |||
399 | return false; | |||
400 | Scale = 0; | |||
401 | BaseRegs.push_back(ScaledReg); | |||
402 | ScaledReg = nullptr; | |||
403 | return true; | |||
404 | } | |||
405 | ||||
406 | /// getNumRegs - Return the total number of register operands used by this | |||
407 | /// formula. This does not include register uses implied by non-constant | |||
408 | /// addrec strides. | |||
409 | size_t Formula::getNumRegs() const { | |||
410 | return !!ScaledReg + BaseRegs.size(); | |||
411 | } | |||
412 | ||||
413 | /// getType - Return the type of this formula, if it has one, or null | |||
414 | /// otherwise. This type is meaningless except for the bit size. | |||
415 | Type *Formula::getType() const { | |||
416 | return !BaseRegs.empty() ? BaseRegs.front()->getType() : | |||
417 | ScaledReg ? ScaledReg->getType() : | |||
418 | BaseGV ? BaseGV->getType() : | |||
419 | nullptr; | |||
420 | } | |||
421 | ||||
422 | /// DeleteBaseReg - Delete the given base reg from the BaseRegs list. | |||
423 | void Formula::DeleteBaseReg(const SCEV *&S) { | |||
424 | if (&S != &BaseRegs.back()) | |||
425 | std::swap(S, BaseRegs.back()); | |||
426 | BaseRegs.pop_back(); | |||
427 | } | |||
428 | ||||
429 | /// referencesReg - Test if this formula references the given register. | |||
430 | bool Formula::referencesReg(const SCEV *S) const { | |||
431 | return S == ScaledReg || | |||
432 | std::find(BaseRegs.begin(), BaseRegs.end(), S) != BaseRegs.end(); | |||
433 | } | |||
434 | ||||
435 | /// hasRegsUsedByUsesOtherThan - Test whether this formula uses registers | |||
436 | /// which are used by uses other than the use with the given index. | |||
437 | bool Formula::hasRegsUsedByUsesOtherThan(size_t LUIdx, | |||
438 | const RegUseTracker &RegUses) const { | |||
439 | if (ScaledReg) | |||
440 | if (RegUses.isRegUsedByUsesOtherThan(ScaledReg, LUIdx)) | |||
441 | return true; | |||
442 | for (const SCEV *BaseReg : BaseRegs) | |||
443 | if (RegUses.isRegUsedByUsesOtherThan(BaseReg, LUIdx)) | |||
444 | return true; | |||
445 | return false; | |||
446 | } | |||
447 | ||||
448 | void Formula::print(raw_ostream &OS) const { | |||
449 | bool First = true; | |||
450 | if (BaseGV) { | |||
451 | if (!First) OS << " + "; else First = false; | |||
452 | BaseGV->printAsOperand(OS, /*PrintType=*/false); | |||
453 | } | |||
454 | if (BaseOffset != 0) { | |||
455 | if (!First) OS << " + "; else First = false; | |||
456 | OS << BaseOffset; | |||
457 | } | |||
458 | for (const SCEV *BaseReg : BaseRegs) { | |||
459 | if (!First) OS << " + "; else First = false; | |||
460 | OS << "reg(" << *BaseReg << ')'; | |||
461 | } | |||
462 | if (HasBaseReg && BaseRegs.empty()) { | |||
463 | if (!First) OS << " + "; else First = false; | |||
464 | OS << "**error: HasBaseReg**"; | |||
465 | } else if (!HasBaseReg && !BaseRegs.empty()) { | |||
466 | if (!First) OS << " + "; else First = false; | |||
467 | OS << "**error: !HasBaseReg**"; | |||
468 | } | |||
469 | if (Scale != 0) { | |||
470 | if (!First) OS << " + "; else First = false; | |||
471 | OS << Scale << "*reg("; | |||
472 | if (ScaledReg) | |||
473 | OS << *ScaledReg; | |||
474 | else | |||
475 | OS << "<unknown>"; | |||
476 | OS << ')'; | |||
477 | } | |||
478 | if (UnfoldedOffset != 0) { | |||
479 | if (!First) OS << " + "; | |||
480 | OS << "imm(" << UnfoldedOffset << ')'; | |||
481 | } | |||
482 | } | |||
483 | ||||
484 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | |||
485 | void Formula::dump() const { | |||
486 | print(errs()); errs() << '\n'; | |||
487 | } | |||
488 | #endif | |||
489 | ||||
490 | /// isAddRecSExtable - Return true if the given addrec can be sign-extended | |||
491 | /// without changing its value. | |||
492 | static bool isAddRecSExtable(const SCEVAddRecExpr *AR, ScalarEvolution &SE) { | |||
493 | Type *WideTy = | |||
494 | IntegerType::get(SE.getContext(), SE.getTypeSizeInBits(AR->getType()) + 1); | |||
495 | return isa<SCEVAddRecExpr>(SE.getSignExtendExpr(AR, WideTy)); | |||
496 | } | |||
497 | ||||
498 | /// isAddSExtable - Return true if the given add can be sign-extended | |||
499 | /// without changing its value. | |||
500 | static bool isAddSExtable(const SCEVAddExpr *A, ScalarEvolution &SE) { | |||
501 | Type *WideTy = | |||
502 | IntegerType::get(SE.getContext(), SE.getTypeSizeInBits(A->getType()) + 1); | |||
503 | return isa<SCEVAddExpr>(SE.getSignExtendExpr(A, WideTy)); | |||
504 | } | |||
505 | ||||
506 | /// isMulSExtable - Return true if the given mul can be sign-extended | |||
507 | /// without changing its value. | |||
508 | static bool isMulSExtable(const SCEVMulExpr *M, ScalarEvolution &SE) { | |||
509 | Type *WideTy = | |||
510 | IntegerType::get(SE.getContext(), | |||
511 | SE.getTypeSizeInBits(M->getType()) * M->getNumOperands()); | |||
512 | return isa<SCEVMulExpr>(SE.getSignExtendExpr(M, WideTy)); | |||
513 | } | |||
514 | ||||
515 | /// getExactSDiv - Return an expression for LHS /s RHS, if it can be determined | |||
516 | /// and if the remainder is known to be zero, or null otherwise. If | |||
517 | /// IgnoreSignificantBits is true, expressions like (X * Y) /s Y are simplified | |||
518 | /// to Y, ignoring that the multiplication may overflow, which is useful when | |||
519 | /// the result will be used in a context where the most significant bits are | |||
520 | /// ignored. | |||
521 | static const SCEV *getExactSDiv(const SCEV *LHS, const SCEV *RHS, | |||
522 | ScalarEvolution &SE, | |||
523 | bool IgnoreSignificantBits = false) { | |||
524 | // Handle the trivial case, which works for any SCEV type. | |||
525 | if (LHS == RHS) | |||
526 | return SE.getConstant(LHS->getType(), 1); | |||
527 | ||||
528 | // Handle a few RHS special cases. | |||
529 | const SCEVConstant *RC = dyn_cast<SCEVConstant>(RHS); | |||
530 | if (RC) { | |||
531 | const APInt &RA = RC->getValue()->getValue(); | |||
532 | // Handle x /s -1 as x * -1, to give ScalarEvolution a chance to do | |||
533 | // some folding. | |||
534 | if (RA.isAllOnesValue()) | |||
535 | return SE.getMulExpr(LHS, RC); | |||
536 | // Handle x /s 1 as x. | |||
537 | if (RA == 1) | |||
538 | return LHS; | |||
539 | } | |||
540 | ||||
541 | // Check for a division of a constant by a constant. | |||
542 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(LHS)) { | |||
543 | if (!RC) | |||
544 | return nullptr; | |||
545 | const APInt &LA = C->getValue()->getValue(); | |||
546 | const APInt &RA = RC->getValue()->getValue(); | |||
547 | if (LA.srem(RA) != 0) | |||
548 | return nullptr; | |||
549 | return SE.getConstant(LA.sdiv(RA)); | |||
550 | } | |||
551 | ||||
552 | // Distribute the sdiv over addrec operands, if the addrec doesn't overflow. | |||
553 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS)) { | |||
554 | if (IgnoreSignificantBits || isAddRecSExtable(AR, SE)) { | |||
555 | const SCEV *Step = getExactSDiv(AR->getStepRecurrence(SE), RHS, SE, | |||
556 | IgnoreSignificantBits); | |||
557 | if (!Step) return nullptr; | |||
558 | const SCEV *Start = getExactSDiv(AR->getStart(), RHS, SE, | |||
559 | IgnoreSignificantBits); | |||
560 | if (!Start) return nullptr; | |||
561 | // FlagNW is independent of the start value, step direction, and is | |||
562 | // preserved with smaller magnitude steps. | |||
563 | // FIXME: AR->getNoWrapFlags(SCEV::FlagNW) | |||
564 | return SE.getAddRecExpr(Start, Step, AR->getLoop(), SCEV::FlagAnyWrap); | |||
565 | } | |||
566 | return nullptr; | |||
567 | } | |||
568 | ||||
569 | // Distribute the sdiv over add operands, if the add doesn't overflow. | |||
570 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(LHS)) { | |||
571 | if (IgnoreSignificantBits || isAddSExtable(Add, SE)) { | |||
572 | SmallVector<const SCEV *, 8> Ops; | |||
573 | for (const SCEV *S : Add->operands()) { | |||
574 | const SCEV *Op = getExactSDiv(S, RHS, SE, IgnoreSignificantBits); | |||
575 | if (!Op) return nullptr; | |||
576 | Ops.push_back(Op); | |||
577 | } | |||
578 | return SE.getAddExpr(Ops); | |||
579 | } | |||
580 | return nullptr; | |||
581 | } | |||
582 | ||||
583 | // Check for a multiply operand that we can pull RHS out of. | |||
584 | if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS)) { | |||
585 | if (IgnoreSignificantBits || isMulSExtable(Mul, SE)) { | |||
586 | SmallVector<const SCEV *, 4> Ops; | |||
587 | bool Found = false; | |||
588 | for (const SCEV *S : Mul->operands()) { | |||
589 | if (!Found) | |||
590 | if (const SCEV *Q = getExactSDiv(S, RHS, SE, | |||
591 | IgnoreSignificantBits)) { | |||
592 | S = Q; | |||
593 | Found = true; | |||
594 | } | |||
595 | Ops.push_back(S); | |||
596 | } | |||
597 | return Found ? SE.getMulExpr(Ops) : nullptr; | |||
598 | } | |||
599 | return nullptr; | |||
600 | } | |||
601 | ||||
602 | // Otherwise we don't know. | |||
603 | return nullptr; | |||
604 | } | |||
605 | ||||
606 | /// ExtractImmediate - If S involves the addition of a constant integer value, | |||
607 | /// return that integer value, and mutate S to point to a new SCEV with that | |||
608 | /// value excluded. | |||
609 | static int64_t ExtractImmediate(const SCEV *&S, ScalarEvolution &SE) { | |||
610 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) { | |||
611 | if (C->getValue()->getValue().getMinSignedBits() <= 64) { | |||
612 | S = SE.getConstant(C->getType(), 0); | |||
613 | return C->getValue()->getSExtValue(); | |||
614 | } | |||
615 | } else if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | |||
616 | SmallVector<const SCEV *, 8> NewOps(Add->op_begin(), Add->op_end()); | |||
617 | int64_t Result = ExtractImmediate(NewOps.front(), SE); | |||
618 | if (Result != 0) | |||
619 | S = SE.getAddExpr(NewOps); | |||
620 | return Result; | |||
621 | } else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) { | |||
622 | SmallVector<const SCEV *, 8> NewOps(AR->op_begin(), AR->op_end()); | |||
623 | int64_t Result = ExtractImmediate(NewOps.front(), SE); | |||
624 | if (Result != 0) | |||
625 | S = SE.getAddRecExpr(NewOps, AR->getLoop(), | |||
626 | // FIXME: AR->getNoWrapFlags(SCEV::FlagNW) | |||
627 | SCEV::FlagAnyWrap); | |||
628 | return Result; | |||
629 | } | |||
630 | return 0; | |||
631 | } | |||
632 | ||||
633 | /// ExtractSymbol - If S involves the addition of a GlobalValue address, | |||
634 | /// return that symbol, and mutate S to point to a new SCEV with that | |||
635 | /// value excluded. | |||
636 | static GlobalValue *ExtractSymbol(const SCEV *&S, ScalarEvolution &SE) { | |||
637 | if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { | |||
638 | if (GlobalValue *GV = dyn_cast<GlobalValue>(U->getValue())) { | |||
639 | S = SE.getConstant(GV->getType(), 0); | |||
640 | return GV; | |||
641 | } | |||
642 | } else if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | |||
643 | SmallVector<const SCEV *, 8> NewOps(Add->op_begin(), Add->op_end()); | |||
644 | GlobalValue *Result = ExtractSymbol(NewOps.back(), SE); | |||
645 | if (Result) | |||
646 | S = SE.getAddExpr(NewOps); | |||
647 | return Result; | |||
648 | } else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) { | |||
649 | SmallVector<const SCEV *, 8> NewOps(AR->op_begin(), AR->op_end()); | |||
650 | GlobalValue *Result = ExtractSymbol(NewOps.front(), SE); | |||
651 | if (Result) | |||
652 | S = SE.getAddRecExpr(NewOps, AR->getLoop(), | |||
653 | // FIXME: AR->getNoWrapFlags(SCEV::FlagNW) | |||
654 | SCEV::FlagAnyWrap); | |||
655 | return Result; | |||
656 | } | |||
657 | return nullptr; | |||
658 | } | |||
659 | ||||
660 | /// isAddressUse - Returns true if the specified instruction is using the | |||
661 | /// specified value as an address. | |||
662 | static bool isAddressUse(Instruction *Inst, Value *OperandVal) { | |||
663 | bool isAddress = isa<LoadInst>(Inst); | |||
664 | if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { | |||
665 | if (SI->getOperand(1) == OperandVal) | |||
666 | isAddress = true; | |||
667 | } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) { | |||
668 | // Addressing modes can also be folded into prefetches and a variety | |||
669 | // of intrinsics. | |||
670 | switch (II->getIntrinsicID()) { | |||
671 | default: break; | |||
672 | case Intrinsic::prefetch: | |||
673 | case Intrinsic::x86_sse_storeu_ps: | |||
674 | case Intrinsic::x86_sse2_storeu_pd: | |||
675 | case Intrinsic::x86_sse2_storeu_dq: | |||
676 | case Intrinsic::x86_sse2_storel_dq: | |||
677 | if (II->getArgOperand(0) == OperandVal) | |||
678 | isAddress = true; | |||
679 | break; | |||
680 | } | |||
681 | } | |||
682 | return isAddress; | |||
683 | } | |||
684 | ||||
685 | /// getAccessType - Return the type of the memory being accessed. | |||
686 | static Type *getAccessType(const Instruction *Inst) { | |||
687 | Type *AccessTy = Inst->getType(); | |||
688 | if (const StoreInst *SI = dyn_cast<StoreInst>(Inst)) | |||
689 | AccessTy = SI->getOperand(0)->getType(); | |||
690 | else if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) { | |||
691 | // Addressing modes can also be folded into prefetches and a variety | |||
692 | // of intrinsics. | |||
693 | switch (II->getIntrinsicID()) { | |||
694 | default: break; | |||
695 | case Intrinsic::x86_sse_storeu_ps: | |||
696 | case Intrinsic::x86_sse2_storeu_pd: | |||
697 | case Intrinsic::x86_sse2_storeu_dq: | |||
698 | case Intrinsic::x86_sse2_storel_dq: | |||
699 | AccessTy = II->getArgOperand(0)->getType(); | |||
700 | break; | |||
701 | } | |||
702 | } | |||
703 | ||||
704 | // All pointers have the same requirements, so canonicalize them to an | |||
705 | // arbitrary pointer type to minimize variation. | |||
706 | if (PointerType *PTy = dyn_cast<PointerType>(AccessTy)) | |||
707 | AccessTy = PointerType::get(IntegerType::get(PTy->getContext(), 1), | |||
708 | PTy->getAddressSpace()); | |||
709 | ||||
710 | return AccessTy; | |||
711 | } | |||
712 | ||||
713 | /// isExistingPhi - Return true if this AddRec is already a phi in its loop. | |||
714 | static bool isExistingPhi(const SCEVAddRecExpr *AR, ScalarEvolution &SE) { | |||
715 | for (BasicBlock::iterator I = AR->getLoop()->getHeader()->begin(); | |||
716 | PHINode *PN = dyn_cast<PHINode>(I); ++I) { | |||
717 | if (SE.isSCEVable(PN->getType()) && | |||
718 | (SE.getEffectiveSCEVType(PN->getType()) == | |||
719 | SE.getEffectiveSCEVType(AR->getType())) && | |||
720 | SE.getSCEV(PN) == AR) | |||
721 | return true; | |||
722 | } | |||
723 | return false; | |||
724 | } | |||
725 | ||||
726 | /// Check if expanding this expression is likely to incur significant cost. This | |||
727 | /// is tricky because SCEV doesn't track which expressions are actually computed | |||
728 | /// by the current IR. | |||
729 | /// | |||
730 | /// We currently allow expansion of IV increments that involve adds, | |||
731 | /// multiplication by constants, and AddRecs from existing phis. | |||
732 | /// | |||
733 | /// TODO: Allow UDivExpr if we can find an existing IV increment that is an | |||
734 | /// obvious multiple of the UDivExpr. | |||
735 | static bool isHighCostExpansion(const SCEV *S, | |||
736 | SmallPtrSetImpl<const SCEV*> &Processed, | |||
737 | ScalarEvolution &SE) { | |||
738 | // Zero/One operand expressions | |||
739 | switch (S->getSCEVType()) { | |||
740 | case scUnknown: | |||
741 | case scConstant: | |||
742 | return false; | |||
743 | case scTruncate: | |||
744 | return isHighCostExpansion(cast<SCEVTruncateExpr>(S)->getOperand(), | |||
745 | Processed, SE); | |||
746 | case scZeroExtend: | |||
747 | return isHighCostExpansion(cast<SCEVZeroExtendExpr>(S)->getOperand(), | |||
748 | Processed, SE); | |||
749 | case scSignExtend: | |||
750 | return isHighCostExpansion(cast<SCEVSignExtendExpr>(S)->getOperand(), | |||
751 | Processed, SE); | |||
752 | } | |||
753 | ||||
754 | if (!Processed.insert(S).second) | |||
755 | return false; | |||
756 | ||||
757 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | |||
758 | for (const SCEV *S : Add->operands()) { | |||
759 | if (isHighCostExpansion(S, Processed, SE)) | |||
760 | return true; | |||
761 | } | |||
762 | return false; | |||
763 | } | |||
764 | ||||
765 | if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) { | |||
766 | if (Mul->getNumOperands() == 2) { | |||
767 | // Multiplication by a constant is ok | |||
768 | if (isa<SCEVConstant>(Mul->getOperand(0))) | |||
769 | return isHighCostExpansion(Mul->getOperand(1), Processed, SE); | |||
770 | ||||
771 | // If we have the value of one operand, check if an existing | |||
772 | // multiplication already generates this expression. | |||
773 | if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(Mul->getOperand(1))) { | |||
774 | Value *UVal = U->getValue(); | |||
775 | for (User *UR : UVal->users()) { | |||
776 | // If U is a constant, it may be used by a ConstantExpr. | |||
777 | Instruction *UI = dyn_cast<Instruction>(UR); | |||
778 | if (UI && UI->getOpcode() == Instruction::Mul && | |||
779 | SE.isSCEVable(UI->getType())) { | |||
780 | return SE.getSCEV(UI) == Mul; | |||
781 | } | |||
782 | } | |||
783 | } | |||
784 | } | |||
785 | } | |||
786 | ||||
787 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) { | |||
788 | if (isExistingPhi(AR, SE)) | |||
789 | return false; | |||
790 | } | |||
791 | ||||
792 | // Fow now, consider any other type of expression (div/mul/min/max) high cost. | |||
793 | return true; | |||
794 | } | |||
795 | ||||
796 | /// DeleteTriviallyDeadInstructions - If any of the instructions is the | |||
797 | /// specified set are trivially dead, delete them and see if this makes any of | |||
798 | /// their operands subsequently dead. | |||
799 | static bool | |||
800 | DeleteTriviallyDeadInstructions(SmallVectorImpl<WeakVH> &DeadInsts) { | |||
801 | bool Changed = false; | |||
802 | ||||
803 | while (!DeadInsts.empty()) { | |||
804 | Value *V = DeadInsts.pop_back_val(); | |||
805 | Instruction *I = dyn_cast_or_null<Instruction>(V); | |||
806 | ||||
807 | if (!I || !isInstructionTriviallyDead(I)) | |||
808 | continue; | |||
809 | ||||
810 | for (Use &O : I->operands()) | |||
811 | if (Instruction *U = dyn_cast<Instruction>(O)) { | |||
812 | O = nullptr; | |||
813 | if (U->use_empty()) | |||
814 | DeadInsts.emplace_back(U); | |||
815 | } | |||
816 | ||||
817 | I->eraseFromParent(); | |||
818 | Changed = true; | |||
819 | } | |||
820 | ||||
821 | return Changed; | |||
822 | } | |||
823 | ||||
824 | namespace { | |||
825 | class LSRUse; | |||
826 | } | |||
827 | ||||
828 | /// \brief Check if the addressing mode defined by \p F is completely | |||
829 | /// folded in \p LU at isel time. | |||
830 | /// This includes address-mode folding and special icmp tricks. | |||
831 | /// This function returns true if \p LU can accommodate what \p F | |||
832 | /// defines and up to 1 base + 1 scaled + offset. | |||
833 | /// In other words, if \p F has several base registers, this function may | |||
834 | /// still return true. Therefore, users still need to account for | |||
835 | /// additional base registers and/or unfolded offsets to derive an | |||
836 | /// accurate cost model. | |||
837 | static bool isAMCompletelyFolded(const TargetTransformInfo &TTI, | |||
838 | const LSRUse &LU, const Formula &F); | |||
839 | // Get the cost of the scaling factor used in F for LU. | |||
840 | static unsigned getScalingFactorCost(const TargetTransformInfo &TTI, | |||
841 | const LSRUse &LU, const Formula &F); | |||
842 | ||||
843 | namespace { | |||
844 | ||||
845 | /// Cost - This class is used to measure and compare candidate formulae. | |||
846 | class Cost { | |||
847 | /// TODO: Some of these could be merged. Also, a lexical ordering | |||
848 | /// isn't always optimal. | |||
849 | unsigned NumRegs; | |||
850 | unsigned AddRecCost; | |||
851 | unsigned NumIVMuls; | |||
852 | unsigned NumBaseAdds; | |||
853 | unsigned ImmCost; | |||
854 | unsigned SetupCost; | |||
855 | unsigned ScaleCost; | |||
856 | ||||
857 | public: | |||
858 | Cost() | |||
859 | : NumRegs(0), AddRecCost(0), NumIVMuls(0), NumBaseAdds(0), ImmCost(0), | |||
860 | SetupCost(0), ScaleCost(0) {} | |||
861 | ||||
862 | bool operator<(const Cost &Other) const; | |||
863 | ||||
864 | void Lose(); | |||
865 | ||||
866 | #ifndef NDEBUG | |||
867 | // Once any of the metrics loses, they must all remain losers. | |||
868 | bool isValid() { | |||
869 | return ((NumRegs | AddRecCost | NumIVMuls | NumBaseAdds | |||
870 | | ImmCost | SetupCost | ScaleCost) != ~0u) | |||
871 | || ((NumRegs & AddRecCost & NumIVMuls & NumBaseAdds | |||
872 | & ImmCost & SetupCost & ScaleCost) == ~0u); | |||
873 | } | |||
874 | #endif | |||
875 | ||||
876 | bool isLoser() { | |||
877 | assert(isValid() && "invalid cost")((isValid() && "invalid cost") ? static_cast<void> (0) : __assert_fail ("isValid() && \"invalid cost\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 877, __PRETTY_FUNCTION__)); | |||
878 | return NumRegs == ~0u; | |||
879 | } | |||
880 | ||||
881 | void RateFormula(const TargetTransformInfo &TTI, | |||
882 | const Formula &F, | |||
883 | SmallPtrSetImpl<const SCEV *> &Regs, | |||
884 | const DenseSet<const SCEV *> &VisitedRegs, | |||
885 | const Loop *L, | |||
886 | const SmallVectorImpl<int64_t> &Offsets, | |||
887 | ScalarEvolution &SE, DominatorTree &DT, | |||
888 | const LSRUse &LU, | |||
889 | SmallPtrSetImpl<const SCEV *> *LoserRegs = nullptr); | |||
890 | ||||
891 | void print(raw_ostream &OS) const; | |||
892 | void dump() const; | |||
893 | ||||
894 | private: | |||
895 | void RateRegister(const SCEV *Reg, | |||
896 | SmallPtrSetImpl<const SCEV *> &Regs, | |||
897 | const Loop *L, | |||
898 | ScalarEvolution &SE, DominatorTree &DT); | |||
899 | void RatePrimaryRegister(const SCEV *Reg, | |||
900 | SmallPtrSetImpl<const SCEV *> &Regs, | |||
901 | const Loop *L, | |||
902 | ScalarEvolution &SE, DominatorTree &DT, | |||
903 | SmallPtrSetImpl<const SCEV *> *LoserRegs); | |||
904 | }; | |||
905 | ||||
906 | } | |||
907 | ||||
908 | /// RateRegister - Tally up interesting quantities from the given register. | |||
909 | void Cost::RateRegister(const SCEV *Reg, | |||
910 | SmallPtrSetImpl<const SCEV *> &Regs, | |||
911 | const Loop *L, | |||
912 | ScalarEvolution &SE, DominatorTree &DT) { | |||
913 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Reg)) { | |||
914 | // If this is an addrec for another loop, don't second-guess its addrec phi | |||
915 | // nodes. LSR isn't currently smart enough to reason about more than one | |||
916 | // loop at a time. LSR has already run on inner loops, will not run on outer | |||
917 | // loops, and cannot be expected to change sibling loops. | |||
918 | if (AR->getLoop() != L) { | |||
919 | // If the AddRec exists, consider it's register free and leave it alone. | |||
920 | if (isExistingPhi(AR, SE)) | |||
921 | return; | |||
922 | ||||
923 | // Otherwise, do not consider this formula at all. | |||
924 | Lose(); | |||
925 | return; | |||
926 | } | |||
927 | AddRecCost += 1; /// TODO: This should be a function of the stride. | |||
928 | ||||
929 | // Add the step value register, if it needs one. | |||
930 | // TODO: The non-affine case isn't precisely modeled here. | |||
931 | if (!AR->isAffine() || !isa<SCEVConstant>(AR->getOperand(1))) { | |||
932 | if (!Regs.count(AR->getOperand(1))) { | |||
933 | RateRegister(AR->getOperand(1), Regs, L, SE, DT); | |||
934 | if (isLoser()) | |||
935 | return; | |||
936 | } | |||
937 | } | |||
938 | } | |||
939 | ++NumRegs; | |||
940 | ||||
941 | // Rough heuristic; favor registers which don't require extra setup | |||
942 | // instructions in the preheader. | |||
943 | if (!isa<SCEVUnknown>(Reg) && | |||
944 | !isa<SCEVConstant>(Reg) && | |||
945 | !(isa<SCEVAddRecExpr>(Reg) && | |||
946 | (isa<SCEVUnknown>(cast<SCEVAddRecExpr>(Reg)->getStart()) || | |||
947 | isa<SCEVConstant>(cast<SCEVAddRecExpr>(Reg)->getStart())))) | |||
948 | ++SetupCost; | |||
949 | ||||
950 | NumIVMuls += isa<SCEVMulExpr>(Reg) && | |||
951 | SE.hasComputableLoopEvolution(Reg, L); | |||
952 | } | |||
953 | ||||
954 | /// RatePrimaryRegister - Record this register in the set. If we haven't seen it | |||
955 | /// before, rate it. Optional LoserRegs provides a way to declare any formula | |||
956 | /// that refers to one of those regs an instant loser. | |||
957 | void Cost::RatePrimaryRegister(const SCEV *Reg, | |||
958 | SmallPtrSetImpl<const SCEV *> &Regs, | |||
959 | const Loop *L, | |||
960 | ScalarEvolution &SE, DominatorTree &DT, | |||
961 | SmallPtrSetImpl<const SCEV *> *LoserRegs) { | |||
962 | if (LoserRegs && LoserRegs->count(Reg)) { | |||
963 | Lose(); | |||
964 | return; | |||
965 | } | |||
966 | if (Regs.insert(Reg).second) { | |||
967 | RateRegister(Reg, Regs, L, SE, DT); | |||
968 | if (LoserRegs && isLoser()) | |||
969 | LoserRegs->insert(Reg); | |||
970 | } | |||
971 | } | |||
972 | ||||
973 | void Cost::RateFormula(const TargetTransformInfo &TTI, | |||
974 | const Formula &F, | |||
975 | SmallPtrSetImpl<const SCEV *> &Regs, | |||
976 | const DenseSet<const SCEV *> &VisitedRegs, | |||
977 | const Loop *L, | |||
978 | const SmallVectorImpl<int64_t> &Offsets, | |||
979 | ScalarEvolution &SE, DominatorTree &DT, | |||
980 | const LSRUse &LU, | |||
981 | SmallPtrSetImpl<const SCEV *> *LoserRegs) { | |||
982 | assert(F.isCanonical() && "Cost is accurate only for canonical formula")((F.isCanonical() && "Cost is accurate only for canonical formula" ) ? static_cast<void> (0) : __assert_fail ("F.isCanonical() && \"Cost is accurate only for canonical formula\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 982, __PRETTY_FUNCTION__)); | |||
983 | // Tally up the registers. | |||
984 | if (const SCEV *ScaledReg = F.ScaledReg) { | |||
985 | if (VisitedRegs.count(ScaledReg)) { | |||
986 | Lose(); | |||
987 | return; | |||
988 | } | |||
989 | RatePrimaryRegister(ScaledReg, Regs, L, SE, DT, LoserRegs); | |||
990 | if (isLoser()) | |||
991 | return; | |||
992 | } | |||
993 | for (const SCEV *BaseReg : F.BaseRegs) { | |||
994 | if (VisitedRegs.count(BaseReg)) { | |||
995 | Lose(); | |||
996 | return; | |||
997 | } | |||
998 | RatePrimaryRegister(BaseReg, Regs, L, SE, DT, LoserRegs); | |||
999 | if (isLoser()) | |||
1000 | return; | |||
1001 | } | |||
1002 | ||||
1003 | // Determine how many (unfolded) adds we'll need inside the loop. | |||
1004 | size_t NumBaseParts = F.getNumRegs(); | |||
1005 | if (NumBaseParts > 1) | |||
1006 | // Do not count the base and a possible second register if the target | |||
1007 | // allows to fold 2 registers. | |||
1008 | NumBaseAdds += | |||
1009 | NumBaseParts - (1 + (F.Scale && isAMCompletelyFolded(TTI, LU, F))); | |||
1010 | NumBaseAdds += (F.UnfoldedOffset != 0); | |||
1011 | ||||
1012 | // Accumulate non-free scaling amounts. | |||
1013 | ScaleCost += getScalingFactorCost(TTI, LU, F); | |||
1014 | ||||
1015 | // Tally up the non-zero immediates. | |||
1016 | for (int64_t O : Offsets) { | |||
1017 | int64_t Offset = (uint64_t)O + F.BaseOffset; | |||
1018 | if (F.BaseGV) | |||
1019 | ImmCost += 64; // Handle symbolic values conservatively. | |||
1020 | // TODO: This should probably be the pointer size. | |||
1021 | else if (Offset != 0) | |||
1022 | ImmCost += APInt(64, Offset, true).getMinSignedBits(); | |||
1023 | } | |||
1024 | assert(isValid() && "invalid cost")((isValid() && "invalid cost") ? static_cast<void> (0) : __assert_fail ("isValid() && \"invalid cost\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1024, __PRETTY_FUNCTION__)); | |||
1025 | } | |||
1026 | ||||
1027 | /// Lose - Set this cost to a losing value. | |||
1028 | void Cost::Lose() { | |||
1029 | NumRegs = ~0u; | |||
1030 | AddRecCost = ~0u; | |||
1031 | NumIVMuls = ~0u; | |||
1032 | NumBaseAdds = ~0u; | |||
1033 | ImmCost = ~0u; | |||
1034 | SetupCost = ~0u; | |||
1035 | ScaleCost = ~0u; | |||
1036 | } | |||
1037 | ||||
1038 | /// operator< - Choose the lower cost. | |||
1039 | bool Cost::operator<(const Cost &Other) const { | |||
1040 | return std::tie(NumRegs, AddRecCost, NumIVMuls, NumBaseAdds, ScaleCost, | |||
1041 | ImmCost, SetupCost) < | |||
1042 | std::tie(Other.NumRegs, Other.AddRecCost, Other.NumIVMuls, | |||
1043 | Other.NumBaseAdds, Other.ScaleCost, Other.ImmCost, | |||
1044 | Other.SetupCost); | |||
1045 | } | |||
1046 | ||||
1047 | void Cost::print(raw_ostream &OS) const { | |||
1048 | OS << NumRegs << " reg" << (NumRegs == 1 ? "" : "s"); | |||
1049 | if (AddRecCost != 0) | |||
1050 | OS << ", with addrec cost " << AddRecCost; | |||
1051 | if (NumIVMuls != 0) | |||
1052 | OS << ", plus " << NumIVMuls << " IV mul" << (NumIVMuls == 1 ? "" : "s"); | |||
1053 | if (NumBaseAdds != 0) | |||
1054 | OS << ", plus " << NumBaseAdds << " base add" | |||
1055 | << (NumBaseAdds == 1 ? "" : "s"); | |||
1056 | if (ScaleCost != 0) | |||
1057 | OS << ", plus " << ScaleCost << " scale cost"; | |||
1058 | if (ImmCost != 0) | |||
1059 | OS << ", plus " << ImmCost << " imm cost"; | |||
1060 | if (SetupCost != 0) | |||
1061 | OS << ", plus " << SetupCost << " setup cost"; | |||
1062 | } | |||
1063 | ||||
1064 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | |||
1065 | void Cost::dump() const { | |||
1066 | print(errs()); errs() << '\n'; | |||
1067 | } | |||
1068 | #endif | |||
1069 | ||||
1070 | namespace { | |||
1071 | ||||
1072 | /// LSRFixup - An operand value in an instruction which is to be replaced | |||
1073 | /// with some equivalent, possibly strength-reduced, replacement. | |||
1074 | struct LSRFixup { | |||
1075 | /// UserInst - The instruction which will be updated. | |||
1076 | Instruction *UserInst; | |||
1077 | ||||
1078 | /// OperandValToReplace - The operand of the instruction which will | |||
1079 | /// be replaced. The operand may be used more than once; every instance | |||
1080 | /// will be replaced. | |||
1081 | Value *OperandValToReplace; | |||
1082 | ||||
1083 | /// PostIncLoops - If this user is to use the post-incremented value of an | |||
1084 | /// induction variable, this variable is non-null and holds the loop | |||
1085 | /// associated with the induction variable. | |||
1086 | PostIncLoopSet PostIncLoops; | |||
1087 | ||||
1088 | /// LUIdx - The index of the LSRUse describing the expression which | |||
1089 | /// this fixup needs, minus an offset (below). | |||
1090 | size_t LUIdx; | |||
1091 | ||||
1092 | /// Offset - A constant offset to be added to the LSRUse expression. | |||
1093 | /// This allows multiple fixups to share the same LSRUse with different | |||
1094 | /// offsets, for example in an unrolled loop. | |||
1095 | int64_t Offset; | |||
1096 | ||||
1097 | bool isUseFullyOutsideLoop(const Loop *L) const; | |||
1098 | ||||
1099 | LSRFixup(); | |||
1100 | ||||
1101 | void print(raw_ostream &OS) const; | |||
1102 | void dump() const; | |||
1103 | }; | |||
1104 | ||||
1105 | } | |||
1106 | ||||
1107 | LSRFixup::LSRFixup() | |||
1108 | : UserInst(nullptr), OperandValToReplace(nullptr), LUIdx(~size_t(0)), | |||
1109 | Offset(0) {} | |||
1110 | ||||
1111 | /// isUseFullyOutsideLoop - Test whether this fixup always uses its | |||
1112 | /// value outside of the given loop. | |||
1113 | bool LSRFixup::isUseFullyOutsideLoop(const Loop *L) const { | |||
1114 | // PHI nodes use their value in their incoming blocks. | |||
1115 | if (const PHINode *PN = dyn_cast<PHINode>(UserInst)) { | |||
1116 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) | |||
1117 | if (PN->getIncomingValue(i) == OperandValToReplace && | |||
1118 | L->contains(PN->getIncomingBlock(i))) | |||
1119 | return false; | |||
1120 | return true; | |||
1121 | } | |||
1122 | ||||
1123 | return !L->contains(UserInst); | |||
1124 | } | |||
1125 | ||||
1126 | void LSRFixup::print(raw_ostream &OS) const { | |||
1127 | OS << "UserInst="; | |||
1128 | // Store is common and interesting enough to be worth special-casing. | |||
1129 | if (StoreInst *Store = dyn_cast<StoreInst>(UserInst)) { | |||
1130 | OS << "store "; | |||
1131 | Store->getOperand(0)->printAsOperand(OS, /*PrintType=*/false); | |||
1132 | } else if (UserInst->getType()->isVoidTy()) | |||
1133 | OS << UserInst->getOpcodeName(); | |||
1134 | else | |||
1135 | UserInst->printAsOperand(OS, /*PrintType=*/false); | |||
1136 | ||||
1137 | OS << ", OperandValToReplace="; | |||
1138 | OperandValToReplace->printAsOperand(OS, /*PrintType=*/false); | |||
1139 | ||||
1140 | for (const Loop *PIL : PostIncLoops) { | |||
1141 | OS << ", PostIncLoop="; | |||
1142 | PIL->getHeader()->printAsOperand(OS, /*PrintType=*/false); | |||
1143 | } | |||
1144 | ||||
1145 | if (LUIdx != ~size_t(0)) | |||
1146 | OS << ", LUIdx=" << LUIdx; | |||
1147 | ||||
1148 | if (Offset != 0) | |||
1149 | OS << ", Offset=" << Offset; | |||
1150 | } | |||
1151 | ||||
1152 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | |||
1153 | void LSRFixup::dump() const { | |||
1154 | print(errs()); errs() << '\n'; | |||
1155 | } | |||
1156 | #endif | |||
1157 | ||||
1158 | namespace { | |||
1159 | ||||
1160 | /// UniquifierDenseMapInfo - A DenseMapInfo implementation for holding | |||
1161 | /// DenseMaps and DenseSets of sorted SmallVectors of const SCEV*. | |||
1162 | struct UniquifierDenseMapInfo { | |||
1163 | static SmallVector<const SCEV *, 4> getEmptyKey() { | |||
1164 | SmallVector<const SCEV *, 4> V; | |||
1165 | V.push_back(reinterpret_cast<const SCEV *>(-1)); | |||
1166 | return V; | |||
1167 | } | |||
1168 | ||||
1169 | static SmallVector<const SCEV *, 4> getTombstoneKey() { | |||
1170 | SmallVector<const SCEV *, 4> V; | |||
1171 | V.push_back(reinterpret_cast<const SCEV *>(-2)); | |||
1172 | return V; | |||
1173 | } | |||
1174 | ||||
1175 | static unsigned getHashValue(const SmallVector<const SCEV *, 4> &V) { | |||
1176 | return static_cast<unsigned>(hash_combine_range(V.begin(), V.end())); | |||
1177 | } | |||
1178 | ||||
1179 | static bool isEqual(const SmallVector<const SCEV *, 4> &LHS, | |||
1180 | const SmallVector<const SCEV *, 4> &RHS) { | |||
1181 | return LHS == RHS; | |||
1182 | } | |||
1183 | }; | |||
1184 | ||||
1185 | /// LSRUse - This class holds the state that LSR keeps for each use in | |||
1186 | /// IVUsers, as well as uses invented by LSR itself. It includes information | |||
1187 | /// about what kinds of things can be folded into the user, information about | |||
1188 | /// the user itself, and information about how the use may be satisfied. | |||
1189 | /// TODO: Represent multiple users of the same expression in common? | |||
1190 | class LSRUse { | |||
1191 | DenseSet<SmallVector<const SCEV *, 4>, UniquifierDenseMapInfo> Uniquifier; | |||
1192 | ||||
1193 | public: | |||
1194 | /// KindType - An enum for a kind of use, indicating what types of | |||
1195 | /// scaled and immediate operands it might support. | |||
1196 | enum KindType { | |||
1197 | Basic, ///< A normal use, with no folding. | |||
1198 | Special, ///< A special case of basic, allowing -1 scales. | |||
1199 | Address, ///< An address use; folding according to TargetLowering | |||
1200 | ICmpZero ///< An equality icmp with both operands folded into one. | |||
1201 | // TODO: Add a generic icmp too? | |||
1202 | }; | |||
1203 | ||||
1204 | typedef PointerIntPair<const SCEV *, 2, KindType> SCEVUseKindPair; | |||
1205 | ||||
1206 | KindType Kind; | |||
1207 | Type *AccessTy; | |||
1208 | ||||
1209 | SmallVector<int64_t, 8> Offsets; | |||
1210 | int64_t MinOffset; | |||
1211 | int64_t MaxOffset; | |||
1212 | ||||
1213 | /// AllFixupsOutsideLoop - This records whether all of the fixups using this | |||
1214 | /// LSRUse are outside of the loop, in which case some special-case heuristics | |||
1215 | /// may be used. | |||
1216 | bool AllFixupsOutsideLoop; | |||
1217 | ||||
1218 | /// RigidFormula is set to true to guarantee that this use will be associated | |||
1219 | /// with a single formula--the one that initially matched. Some SCEV | |||
1220 | /// expressions cannot be expanded. This allows LSR to consider the registers | |||
1221 | /// used by those expressions without the need to expand them later after | |||
1222 | /// changing the formula. | |||
1223 | bool RigidFormula; | |||
1224 | ||||
1225 | /// WidestFixupType - This records the widest use type for any fixup using | |||
1226 | /// this LSRUse. FindUseWithSimilarFormula can't consider uses with different | |||
1227 | /// max fixup widths to be equivalent, because the narrower one may be relying | |||
1228 | /// on the implicit truncation to truncate away bogus bits. | |||
1229 | Type *WidestFixupType; | |||
1230 | ||||
1231 | /// Formulae - A list of ways to build a value that can satisfy this user. | |||
1232 | /// After the list is populated, one of these is selected heuristically and | |||
1233 | /// used to formulate a replacement for OperandValToReplace in UserInst. | |||
1234 | SmallVector<Formula, 12> Formulae; | |||
1235 | ||||
1236 | /// Regs - The set of register candidates used by all formulae in this LSRUse. | |||
1237 | SmallPtrSet<const SCEV *, 4> Regs; | |||
1238 | ||||
1239 | LSRUse(KindType K, Type *T) : Kind(K), AccessTy(T), | |||
1240 | MinOffset(INT64_MAX(9223372036854775807L)), | |||
1241 | MaxOffset(INT64_MIN(-9223372036854775807L -1)), | |||
1242 | AllFixupsOutsideLoop(true), | |||
1243 | RigidFormula(false), | |||
1244 | WidestFixupType(nullptr) {} | |||
1245 | ||||
1246 | bool HasFormulaWithSameRegs(const Formula &F) const; | |||
1247 | bool InsertFormula(const Formula &F); | |||
1248 | void DeleteFormula(Formula &F); | |||
1249 | void RecomputeRegs(size_t LUIdx, RegUseTracker &Reguses); | |||
1250 | ||||
1251 | void print(raw_ostream &OS) const; | |||
1252 | void dump() const; | |||
1253 | }; | |||
1254 | ||||
1255 | } | |||
1256 | ||||
1257 | /// HasFormula - Test whether this use as a formula which has the same | |||
1258 | /// registers as the given formula. | |||
1259 | bool LSRUse::HasFormulaWithSameRegs(const Formula &F) const { | |||
1260 | SmallVector<const SCEV *, 4> Key = F.BaseRegs; | |||
1261 | if (F.ScaledReg) Key.push_back(F.ScaledReg); | |||
1262 | // Unstable sort by host order ok, because this is only used for uniquifying. | |||
1263 | std::sort(Key.begin(), Key.end()); | |||
1264 | return Uniquifier.count(Key); | |||
1265 | } | |||
1266 | ||||
1267 | /// InsertFormula - If the given formula has not yet been inserted, add it to | |||
1268 | /// the list, and return true. Return false otherwise. | |||
1269 | /// The formula must be in canonical form. | |||
1270 | bool LSRUse::InsertFormula(const Formula &F) { | |||
1271 | assert(F.isCanonical() && "Invalid canonical representation")((F.isCanonical() && "Invalid canonical representation" ) ? static_cast<void> (0) : __assert_fail ("F.isCanonical() && \"Invalid canonical representation\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1271, __PRETTY_FUNCTION__)); | |||
1272 | ||||
1273 | if (!Formulae.empty() && RigidFormula) | |||
1274 | return false; | |||
1275 | ||||
1276 | SmallVector<const SCEV *, 4> Key = F.BaseRegs; | |||
1277 | if (F.ScaledReg) Key.push_back(F.ScaledReg); | |||
1278 | // Unstable sort by host order ok, because this is only used for uniquifying. | |||
1279 | std::sort(Key.begin(), Key.end()); | |||
1280 | ||||
1281 | if (!Uniquifier.insert(Key).second) | |||
1282 | return false; | |||
1283 | ||||
1284 | // Using a register to hold the value of 0 is not profitable. | |||
1285 | assert((!F.ScaledReg || !F.ScaledReg->isZero()) &&(((!F.ScaledReg || !F.ScaledReg->isZero()) && "Zero allocated in a scaled register!" ) ? static_cast<void> (0) : __assert_fail ("(!F.ScaledReg || !F.ScaledReg->isZero()) && \"Zero allocated in a scaled register!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1286, __PRETTY_FUNCTION__)) | |||
1286 | "Zero allocated in a scaled register!")(((!F.ScaledReg || !F.ScaledReg->isZero()) && "Zero allocated in a scaled register!" ) ? static_cast<void> (0) : __assert_fail ("(!F.ScaledReg || !F.ScaledReg->isZero()) && \"Zero allocated in a scaled register!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1286, __PRETTY_FUNCTION__)); | |||
1287 | #ifndef NDEBUG | |||
1288 | for (const SCEV *BaseReg : F.BaseRegs) | |||
1289 | assert(!BaseReg->isZero() && "Zero allocated in a base register!")((!BaseReg->isZero() && "Zero allocated in a base register!" ) ? static_cast<void> (0) : __assert_fail ("!BaseReg->isZero() && \"Zero allocated in a base register!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1289, __PRETTY_FUNCTION__)); | |||
1290 | #endif | |||
1291 | ||||
1292 | // Add the formula to the list. | |||
1293 | Formulae.push_back(F); | |||
1294 | ||||
1295 | // Record registers now being used by this use. | |||
1296 | Regs.insert(F.BaseRegs.begin(), F.BaseRegs.end()); | |||
1297 | if (F.ScaledReg) | |||
1298 | Regs.insert(F.ScaledReg); | |||
1299 | ||||
1300 | return true; | |||
1301 | } | |||
1302 | ||||
1303 | /// DeleteFormula - Remove the given formula from this use's list. | |||
1304 | void LSRUse::DeleteFormula(Formula &F) { | |||
1305 | if (&F != &Formulae.back()) | |||
1306 | std::swap(F, Formulae.back()); | |||
1307 | Formulae.pop_back(); | |||
1308 | } | |||
1309 | ||||
1310 | /// RecomputeRegs - Recompute the Regs field, and update RegUses. | |||
1311 | void LSRUse::RecomputeRegs(size_t LUIdx, RegUseTracker &RegUses) { | |||
1312 | // Now that we've filtered out some formulae, recompute the Regs set. | |||
1313 | SmallPtrSet<const SCEV *, 4> OldRegs = std::move(Regs); | |||
1314 | Regs.clear(); | |||
1315 | for (const Formula &F : Formulae) { | |||
1316 | if (F.ScaledReg) Regs.insert(F.ScaledReg); | |||
1317 | Regs.insert(F.BaseRegs.begin(), F.BaseRegs.end()); | |||
1318 | } | |||
1319 | ||||
1320 | // Update the RegTracker. | |||
1321 | for (const SCEV *S : OldRegs) | |||
1322 | if (!Regs.count(S)) | |||
1323 | RegUses.DropRegister(S, LUIdx); | |||
1324 | } | |||
1325 | ||||
1326 | void LSRUse::print(raw_ostream &OS) const { | |||
1327 | OS << "LSR Use: Kind="; | |||
1328 | switch (Kind) { | |||
1329 | case Basic: OS << "Basic"; break; | |||
1330 | case Special: OS << "Special"; break; | |||
1331 | case ICmpZero: OS << "ICmpZero"; break; | |||
1332 | case Address: | |||
1333 | OS << "Address of "; | |||
1334 | if (AccessTy->isPointerTy()) | |||
1335 | OS << "pointer"; // the full pointer type could be really verbose | |||
1336 | else | |||
1337 | OS << *AccessTy; | |||
1338 | } | |||
1339 | ||||
1340 | OS << ", Offsets={"; | |||
1341 | bool NeedComma = false; | |||
1342 | for (int64_t O : Offsets) { | |||
1343 | if (NeedComma) OS << ','; | |||
1344 | OS << O; | |||
1345 | NeedComma = true; | |||
1346 | } | |||
1347 | OS << '}'; | |||
1348 | ||||
1349 | if (AllFixupsOutsideLoop) | |||
1350 | OS << ", all-fixups-outside-loop"; | |||
1351 | ||||
1352 | if (WidestFixupType) | |||
1353 | OS << ", widest fixup type: " << *WidestFixupType; | |||
1354 | } | |||
1355 | ||||
1356 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | |||
1357 | void LSRUse::dump() const { | |||
1358 | print(errs()); errs() << '\n'; | |||
1359 | } | |||
1360 | #endif | |||
1361 | ||||
1362 | static bool isAMCompletelyFolded(const TargetTransformInfo &TTI, | |||
1363 | LSRUse::KindType Kind, Type *AccessTy, | |||
1364 | GlobalValue *BaseGV, int64_t BaseOffset, | |||
1365 | bool HasBaseReg, int64_t Scale) { | |||
1366 | switch (Kind) { | |||
1367 | case LSRUse::Address: | |||
1368 | return TTI.isLegalAddressingMode(AccessTy, BaseGV, BaseOffset, HasBaseReg, Scale); | |||
1369 | ||||
1370 | case LSRUse::ICmpZero: | |||
1371 | // There's not even a target hook for querying whether it would be legal to | |||
1372 | // fold a GV into an ICmp. | |||
1373 | if (BaseGV) | |||
1374 | return false; | |||
1375 | ||||
1376 | // ICmp only has two operands; don't allow more than two non-trivial parts. | |||
1377 | if (Scale != 0 && HasBaseReg && BaseOffset != 0) | |||
1378 | return false; | |||
1379 | ||||
1380 | // ICmp only supports no scale or a -1 scale, as we can "fold" a -1 scale by | |||
1381 | // putting the scaled register in the other operand of the icmp. | |||
1382 | if (Scale != 0 && Scale != -1) | |||
1383 | return false; | |||
1384 | ||||
1385 | // If we have low-level target information, ask the target if it can fold an | |||
1386 | // integer immediate on an icmp. | |||
1387 | if (BaseOffset != 0) { | |||
1388 | // We have one of: | |||
1389 | // ICmpZero BaseReg + BaseOffset => ICmp BaseReg, -BaseOffset | |||
1390 | // ICmpZero -1*ScaleReg + BaseOffset => ICmp ScaleReg, BaseOffset | |||
1391 | // Offs is the ICmp immediate. | |||
1392 | if (Scale == 0) | |||
1393 | // The cast does the right thing with INT64_MIN. | |||
1394 | BaseOffset = -(uint64_t)BaseOffset; | |||
1395 | return TTI.isLegalICmpImmediate(BaseOffset); | |||
1396 | } | |||
1397 | ||||
1398 | // ICmpZero BaseReg + -1*ScaleReg => ICmp BaseReg, ScaleReg | |||
1399 | return true; | |||
1400 | ||||
1401 | case LSRUse::Basic: | |||
1402 | // Only handle single-register values. | |||
1403 | return !BaseGV && Scale == 0 && BaseOffset == 0; | |||
1404 | ||||
1405 | case LSRUse::Special: | |||
1406 | // Special case Basic to handle -1 scales. | |||
1407 | return !BaseGV && (Scale == 0 || Scale == -1) && BaseOffset == 0; | |||
1408 | } | |||
1409 | ||||
1410 | llvm_unreachable("Invalid LSRUse Kind!")::llvm::llvm_unreachable_internal("Invalid LSRUse Kind!", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1410); | |||
1411 | } | |||
1412 | ||||
1413 | static bool isAMCompletelyFolded(const TargetTransformInfo &TTI, | |||
1414 | int64_t MinOffset, int64_t MaxOffset, | |||
1415 | LSRUse::KindType Kind, Type *AccessTy, | |||
1416 | GlobalValue *BaseGV, int64_t BaseOffset, | |||
1417 | bool HasBaseReg, int64_t Scale) { | |||
1418 | // Check for overflow. | |||
1419 | if (((int64_t)((uint64_t)BaseOffset + MinOffset) > BaseOffset) != | |||
1420 | (MinOffset > 0)) | |||
1421 | return false; | |||
1422 | MinOffset = (uint64_t)BaseOffset + MinOffset; | |||
1423 | if (((int64_t)((uint64_t)BaseOffset + MaxOffset) > BaseOffset) != | |||
1424 | (MaxOffset > 0)) | |||
1425 | return false; | |||
1426 | MaxOffset = (uint64_t)BaseOffset + MaxOffset; | |||
1427 | ||||
1428 | return isAMCompletelyFolded(TTI, Kind, AccessTy, BaseGV, MinOffset, | |||
1429 | HasBaseReg, Scale) && | |||
1430 | isAMCompletelyFolded(TTI, Kind, AccessTy, BaseGV, MaxOffset, | |||
1431 | HasBaseReg, Scale); | |||
1432 | } | |||
1433 | ||||
1434 | static bool isAMCompletelyFolded(const TargetTransformInfo &TTI, | |||
1435 | int64_t MinOffset, int64_t MaxOffset, | |||
1436 | LSRUse::KindType Kind, Type *AccessTy, | |||
1437 | const Formula &F) { | |||
1438 | // For the purpose of isAMCompletelyFolded either having a canonical formula | |||
1439 | // or a scale not equal to zero is correct. | |||
1440 | // Problems may arise from non canonical formulae having a scale == 0. | |||
1441 | // Strictly speaking it would best to just rely on canonical formulae. | |||
1442 | // However, when we generate the scaled formulae, we first check that the | |||
1443 | // scaling factor is profitable before computing the actual ScaledReg for | |||
1444 | // compile time sake. | |||
1445 | assert((F.isCanonical() || F.Scale != 0))(((F.isCanonical() || F.Scale != 0)) ? static_cast<void> (0) : __assert_fail ("(F.isCanonical() || F.Scale != 0)", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1445, __PRETTY_FUNCTION__)); | |||
1446 | return isAMCompletelyFolded(TTI, MinOffset, MaxOffset, Kind, AccessTy, | |||
1447 | F.BaseGV, F.BaseOffset, F.HasBaseReg, F.Scale); | |||
1448 | } | |||
1449 | ||||
1450 | /// isLegalUse - Test whether we know how to expand the current formula. | |||
1451 | static bool isLegalUse(const TargetTransformInfo &TTI, int64_t MinOffset, | |||
1452 | int64_t MaxOffset, LSRUse::KindType Kind, Type *AccessTy, | |||
1453 | GlobalValue *BaseGV, int64_t BaseOffset, bool HasBaseReg, | |||
1454 | int64_t Scale) { | |||
1455 | // We know how to expand completely foldable formulae. | |||
1456 | return isAMCompletelyFolded(TTI, MinOffset, MaxOffset, Kind, AccessTy, BaseGV, | |||
1457 | BaseOffset, HasBaseReg, Scale) || | |||
1458 | // Or formulae that use a base register produced by a sum of base | |||
1459 | // registers. | |||
1460 | (Scale == 1 && | |||
1461 | isAMCompletelyFolded(TTI, MinOffset, MaxOffset, Kind, AccessTy, | |||
1462 | BaseGV, BaseOffset, true, 0)); | |||
1463 | } | |||
1464 | ||||
1465 | static bool isLegalUse(const TargetTransformInfo &TTI, int64_t MinOffset, | |||
1466 | int64_t MaxOffset, LSRUse::KindType Kind, Type *AccessTy, | |||
1467 | const Formula &F) { | |||
1468 | return isLegalUse(TTI, MinOffset, MaxOffset, Kind, AccessTy, F.BaseGV, | |||
1469 | F.BaseOffset, F.HasBaseReg, F.Scale); | |||
1470 | } | |||
1471 | ||||
1472 | static bool isAMCompletelyFolded(const TargetTransformInfo &TTI, | |||
1473 | const LSRUse &LU, const Formula &F) { | |||
1474 | return isAMCompletelyFolded(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, | |||
1475 | LU.AccessTy, F.BaseGV, F.BaseOffset, F.HasBaseReg, | |||
1476 | F.Scale); | |||
1477 | } | |||
1478 | ||||
1479 | static unsigned getScalingFactorCost(const TargetTransformInfo &TTI, | |||
1480 | const LSRUse &LU, const Formula &F) { | |||
1481 | if (!F.Scale) | |||
1482 | return 0; | |||
1483 | ||||
1484 | // If the use is not completely folded in that instruction, we will have to | |||
1485 | // pay an extra cost only for scale != 1. | |||
1486 | if (!isAMCompletelyFolded(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, | |||
1487 | LU.AccessTy, F)) | |||
1488 | return F.Scale != 1; | |||
1489 | ||||
1490 | switch (LU.Kind) { | |||
1491 | case LSRUse::Address: { | |||
1492 | // Check the scaling factor cost with both the min and max offsets. | |||
1493 | int ScaleCostMinOffset = | |||
1494 | TTI.getScalingFactorCost(LU.AccessTy, F.BaseGV, | |||
1495 | F.BaseOffset + LU.MinOffset, | |||
1496 | F.HasBaseReg, F.Scale); | |||
1497 | int ScaleCostMaxOffset = | |||
1498 | TTI.getScalingFactorCost(LU.AccessTy, F.BaseGV, | |||
1499 | F.BaseOffset + LU.MaxOffset, | |||
1500 | F.HasBaseReg, F.Scale); | |||
1501 | ||||
1502 | assert(ScaleCostMinOffset >= 0 && ScaleCostMaxOffset >= 0 &&((ScaleCostMinOffset >= 0 && ScaleCostMaxOffset >= 0 && "Legal addressing mode has an illegal cost!") ? static_cast<void> (0) : __assert_fail ("ScaleCostMinOffset >= 0 && ScaleCostMaxOffset >= 0 && \"Legal addressing mode has an illegal cost!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1503, __PRETTY_FUNCTION__)) | |||
1503 | "Legal addressing mode has an illegal cost!")((ScaleCostMinOffset >= 0 && ScaleCostMaxOffset >= 0 && "Legal addressing mode has an illegal cost!") ? static_cast<void> (0) : __assert_fail ("ScaleCostMinOffset >= 0 && ScaleCostMaxOffset >= 0 && \"Legal addressing mode has an illegal cost!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1503, __PRETTY_FUNCTION__)); | |||
1504 | return std::max(ScaleCostMinOffset, ScaleCostMaxOffset); | |||
1505 | } | |||
1506 | case LSRUse::ICmpZero: | |||
1507 | case LSRUse::Basic: | |||
1508 | case LSRUse::Special: | |||
1509 | // The use is completely folded, i.e., everything is folded into the | |||
1510 | // instruction. | |||
1511 | return 0; | |||
1512 | } | |||
1513 | ||||
1514 | llvm_unreachable("Invalid LSRUse Kind!")::llvm::llvm_unreachable_internal("Invalid LSRUse Kind!", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1514); | |||
1515 | } | |||
1516 | ||||
1517 | static bool isAlwaysFoldable(const TargetTransformInfo &TTI, | |||
1518 | LSRUse::KindType Kind, Type *AccessTy, | |||
1519 | GlobalValue *BaseGV, int64_t BaseOffset, | |||
1520 | bool HasBaseReg) { | |||
1521 | // Fast-path: zero is always foldable. | |||
1522 | if (BaseOffset == 0 && !BaseGV) return true; | |||
1523 | ||||
1524 | // Conservatively, create an address with an immediate and a | |||
1525 | // base and a scale. | |||
1526 | int64_t Scale = Kind == LSRUse::ICmpZero ? -1 : 1; | |||
1527 | ||||
1528 | // Canonicalize a scale of 1 to a base register if the formula doesn't | |||
1529 | // already have a base register. | |||
1530 | if (!HasBaseReg && Scale == 1) { | |||
1531 | Scale = 0; | |||
1532 | HasBaseReg = true; | |||
1533 | } | |||
1534 | ||||
1535 | return isAMCompletelyFolded(TTI, Kind, AccessTy, BaseGV, BaseOffset, | |||
1536 | HasBaseReg, Scale); | |||
1537 | } | |||
1538 | ||||
1539 | static bool isAlwaysFoldable(const TargetTransformInfo &TTI, | |||
1540 | ScalarEvolution &SE, int64_t MinOffset, | |||
1541 | int64_t MaxOffset, LSRUse::KindType Kind, | |||
1542 | Type *AccessTy, const SCEV *S, bool HasBaseReg) { | |||
1543 | // Fast-path: zero is always foldable. | |||
1544 | if (S->isZero()) return true; | |||
1545 | ||||
1546 | // Conservatively, create an address with an immediate and a | |||
1547 | // base and a scale. | |||
1548 | int64_t BaseOffset = ExtractImmediate(S, SE); | |||
1549 | GlobalValue *BaseGV = ExtractSymbol(S, SE); | |||
1550 | ||||
1551 | // If there's anything else involved, it's not foldable. | |||
1552 | if (!S->isZero()) return false; | |||
1553 | ||||
1554 | // Fast-path: zero is always foldable. | |||
1555 | if (BaseOffset == 0 && !BaseGV) return true; | |||
1556 | ||||
1557 | // Conservatively, create an address with an immediate and a | |||
1558 | // base and a scale. | |||
1559 | int64_t Scale = Kind == LSRUse::ICmpZero ? -1 : 1; | |||
1560 | ||||
1561 | return isAMCompletelyFolded(TTI, MinOffset, MaxOffset, Kind, AccessTy, BaseGV, | |||
1562 | BaseOffset, HasBaseReg, Scale); | |||
1563 | } | |||
1564 | ||||
1565 | namespace { | |||
1566 | ||||
1567 | /// IVInc - An individual increment in a Chain of IV increments. | |||
1568 | /// Relate an IV user to an expression that computes the IV it uses from the IV | |||
1569 | /// used by the previous link in the Chain. | |||
1570 | /// | |||
1571 | /// For the head of a chain, IncExpr holds the absolute SCEV expression for the | |||
1572 | /// original IVOperand. The head of the chain's IVOperand is only valid during | |||
1573 | /// chain collection, before LSR replaces IV users. During chain generation, | |||
1574 | /// IncExpr can be used to find the new IVOperand that computes the same | |||
1575 | /// expression. | |||
1576 | struct IVInc { | |||
1577 | Instruction *UserInst; | |||
1578 | Value* IVOperand; | |||
1579 | const SCEV *IncExpr; | |||
1580 | ||||
1581 | IVInc(Instruction *U, Value *O, const SCEV *E): | |||
1582 | UserInst(U), IVOperand(O), IncExpr(E) {} | |||
1583 | }; | |||
1584 | ||||
1585 | // IVChain - The list of IV increments in program order. | |||
1586 | // We typically add the head of a chain without finding subsequent links. | |||
1587 | struct IVChain { | |||
1588 | SmallVector<IVInc,1> Incs; | |||
1589 | const SCEV *ExprBase; | |||
1590 | ||||
1591 | IVChain() : ExprBase(nullptr) {} | |||
1592 | ||||
1593 | IVChain(const IVInc &Head, const SCEV *Base) | |||
1594 | : Incs(1, Head), ExprBase(Base) {} | |||
1595 | ||||
1596 | typedef SmallVectorImpl<IVInc>::const_iterator const_iterator; | |||
1597 | ||||
1598 | // begin - return the first increment in the chain. | |||
1599 | const_iterator begin() const { | |||
1600 | assert(!Incs.empty())((!Incs.empty()) ? static_cast<void> (0) : __assert_fail ("!Incs.empty()", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 1600, __PRETTY_FUNCTION__)); | |||
1601 | return std::next(Incs.begin()); | |||
1602 | } | |||
1603 | const_iterator end() const { | |||
1604 | return Incs.end(); | |||
1605 | } | |||
1606 | ||||
1607 | // hasIncs - Returns true if this chain contains any increments. | |||
1608 | bool hasIncs() const { return Incs.size() >= 2; } | |||
1609 | ||||
1610 | // add - Add an IVInc to the end of this chain. | |||
1611 | void add(const IVInc &X) { Incs.push_back(X); } | |||
1612 | ||||
1613 | // tailUserInst - Returns the last UserInst in the chain. | |||
1614 | Instruction *tailUserInst() const { return Incs.back().UserInst; } | |||
1615 | ||||
1616 | // isProfitableIncrement - Returns true if IncExpr can be profitably added to | |||
1617 | // this chain. | |||
1618 | bool isProfitableIncrement(const SCEV *OperExpr, | |||
1619 | const SCEV *IncExpr, | |||
1620 | ScalarEvolution&); | |||
1621 | }; | |||
1622 | ||||
1623 | /// ChainUsers - Helper for CollectChains to track multiple IV increment uses. | |||
1624 | /// Distinguish between FarUsers that definitely cross IV increments and | |||
1625 | /// NearUsers that may be used between IV increments. | |||
1626 | struct ChainUsers { | |||
1627 | SmallPtrSet<Instruction*, 4> FarUsers; | |||
1628 | SmallPtrSet<Instruction*, 4> NearUsers; | |||
1629 | }; | |||
1630 | ||||
1631 | /// LSRInstance - This class holds state for the main loop strength reduction | |||
1632 | /// logic. | |||
1633 | class LSRInstance { | |||
1634 | IVUsers &IU; | |||
1635 | ScalarEvolution &SE; | |||
1636 | DominatorTree &DT; | |||
1637 | LoopInfo &LI; | |||
1638 | const TargetTransformInfo &TTI; | |||
1639 | Loop *const L; | |||
1640 | bool Changed; | |||
1641 | ||||
1642 | /// IVIncInsertPos - This is the insert position that the current loop's | |||
1643 | /// induction variable increment should be placed. In simple loops, this is | |||
1644 | /// the latch block's terminator. But in more complicated cases, this is a | |||
1645 | /// position which will dominate all the in-loop post-increment users. | |||
1646 | Instruction *IVIncInsertPos; | |||
1647 | ||||
1648 | /// Factors - Interesting factors between use strides. | |||
1649 | SmallSetVector<int64_t, 8> Factors; | |||
1650 | ||||
1651 | /// Types - Interesting use types, to facilitate truncation reuse. | |||
1652 | SmallSetVector<Type *, 4> Types; | |||
1653 | ||||
1654 | /// Fixups - The list of operands which are to be replaced. | |||
1655 | SmallVector<LSRFixup, 16> Fixups; | |||
1656 | ||||
1657 | /// Uses - The list of interesting uses. | |||
1658 | SmallVector<LSRUse, 16> Uses; | |||
1659 | ||||
1660 | /// RegUses - Track which uses use which register candidates. | |||
1661 | RegUseTracker RegUses; | |||
1662 | ||||
1663 | // Limit the number of chains to avoid quadratic behavior. We don't expect to | |||
1664 | // have more than a few IV increment chains in a loop. Missing a Chain falls | |||
1665 | // back to normal LSR behavior for those uses. | |||
1666 | static const unsigned MaxChains = 8; | |||
1667 | ||||
1668 | /// IVChainVec - IV users can form a chain of IV increments. | |||
1669 | SmallVector<IVChain, MaxChains> IVChainVec; | |||
1670 | ||||
1671 | /// IVIncSet - IV users that belong to profitable IVChains. | |||
1672 | SmallPtrSet<Use*, MaxChains> IVIncSet; | |||
1673 | ||||
1674 | void OptimizeShadowIV(); | |||
1675 | bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse); | |||
1676 | ICmpInst *OptimizeMax(ICmpInst *Cond, IVStrideUse* &CondUse); | |||
1677 | void OptimizeLoopTermCond(); | |||
1678 | ||||
1679 | void ChainInstruction(Instruction *UserInst, Instruction *IVOper, | |||
1680 | SmallVectorImpl<ChainUsers> &ChainUsersVec); | |||
1681 | void FinalizeChain(IVChain &Chain); | |||
1682 | void CollectChains(); | |||
1683 | void GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter, | |||
1684 | SmallVectorImpl<WeakVH> &DeadInsts); | |||
1685 | ||||
1686 | void CollectInterestingTypesAndFactors(); | |||
1687 | void CollectFixupsAndInitialFormulae(); | |||
1688 | ||||
1689 | LSRFixup &getNewFixup() { | |||
1690 | Fixups.push_back(LSRFixup()); | |||
1691 | return Fixups.back(); | |||
1692 | } | |||
1693 | ||||
1694 | // Support for sharing of LSRUses between LSRFixups. | |||
1695 | typedef DenseMap<LSRUse::SCEVUseKindPair, size_t> UseMapTy; | |||
1696 | UseMapTy UseMap; | |||
1697 | ||||
1698 | bool reconcileNewOffset(LSRUse &LU, int64_t NewOffset, bool HasBaseReg, | |||
1699 | LSRUse::KindType Kind, Type *AccessTy); | |||
1700 | ||||
1701 | std::pair<size_t, int64_t> getUse(const SCEV *&Expr, | |||
1702 | LSRUse::KindType Kind, | |||
1703 | Type *AccessTy); | |||
1704 | ||||
1705 | void DeleteUse(LSRUse &LU, size_t LUIdx); | |||
1706 | ||||
1707 | LSRUse *FindUseWithSimilarFormula(const Formula &F, const LSRUse &OrigLU); | |||
1708 | ||||
1709 | void InsertInitialFormula(const SCEV *S, LSRUse &LU, size_t LUIdx); | |||
1710 | void InsertSupplementalFormula(const SCEV *S, LSRUse &LU, size_t LUIdx); | |||
1711 | void CountRegisters(const Formula &F, size_t LUIdx); | |||
1712 | bool InsertFormula(LSRUse &LU, unsigned LUIdx, const Formula &F); | |||
1713 | ||||
1714 | void CollectLoopInvariantFixupsAndFormulae(); | |||
1715 | ||||
1716 | void GenerateReassociations(LSRUse &LU, unsigned LUIdx, Formula Base, | |||
1717 | unsigned Depth = 0); | |||
1718 | ||||
1719 | void GenerateReassociationsImpl(LSRUse &LU, unsigned LUIdx, | |||
1720 | const Formula &Base, unsigned Depth, | |||
1721 | size_t Idx, bool IsScaledReg = false); | |||
1722 | void GenerateCombinations(LSRUse &LU, unsigned LUIdx, Formula Base); | |||
1723 | void GenerateSymbolicOffsetsImpl(LSRUse &LU, unsigned LUIdx, | |||
1724 | const Formula &Base, size_t Idx, | |||
1725 | bool IsScaledReg = false); | |||
1726 | void GenerateSymbolicOffsets(LSRUse &LU, unsigned LUIdx, Formula Base); | |||
1727 | void GenerateConstantOffsetsImpl(LSRUse &LU, unsigned LUIdx, | |||
1728 | const Formula &Base, | |||
1729 | const SmallVectorImpl<int64_t> &Worklist, | |||
1730 | size_t Idx, bool IsScaledReg = false); | |||
1731 | void GenerateConstantOffsets(LSRUse &LU, unsigned LUIdx, Formula Base); | |||
1732 | void GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx, Formula Base); | |||
1733 | void GenerateScales(LSRUse &LU, unsigned LUIdx, Formula Base); | |||
1734 | void GenerateTruncates(LSRUse &LU, unsigned LUIdx, Formula Base); | |||
1735 | void GenerateCrossUseConstantOffsets(); | |||
1736 | void GenerateAllReuseFormulae(); | |||
1737 | ||||
1738 | void FilterOutUndesirableDedicatedRegisters(); | |||
1739 | ||||
1740 | size_t EstimateSearchSpaceComplexity() const; | |||
1741 | void NarrowSearchSpaceByDetectingSupersets(); | |||
1742 | void NarrowSearchSpaceByCollapsingUnrolledCode(); | |||
1743 | void NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters(); | |||
1744 | void NarrowSearchSpaceByPickingWinnerRegs(); | |||
1745 | void NarrowSearchSpaceUsingHeuristics(); | |||
1746 | ||||
1747 | void SolveRecurse(SmallVectorImpl<const Formula *> &Solution, | |||
1748 | Cost &SolutionCost, | |||
1749 | SmallVectorImpl<const Formula *> &Workspace, | |||
1750 | const Cost &CurCost, | |||
1751 | const SmallPtrSet<const SCEV *, 16> &CurRegs, | |||
1752 | DenseSet<const SCEV *> &VisitedRegs) const; | |||
1753 | void Solve(SmallVectorImpl<const Formula *> &Solution) const; | |||
1754 | ||||
1755 | BasicBlock::iterator | |||
1756 | HoistInsertPosition(BasicBlock::iterator IP, | |||
1757 | const SmallVectorImpl<Instruction *> &Inputs) const; | |||
1758 | BasicBlock::iterator | |||
1759 | AdjustInsertPositionForExpand(BasicBlock::iterator IP, | |||
1760 | const LSRFixup &LF, | |||
1761 | const LSRUse &LU, | |||
1762 | SCEVExpander &Rewriter) const; | |||
1763 | ||||
1764 | Value *Expand(const LSRFixup &LF, | |||
1765 | const Formula &F, | |||
1766 | BasicBlock::iterator IP, | |||
1767 | SCEVExpander &Rewriter, | |||
1768 | SmallVectorImpl<WeakVH> &DeadInsts) const; | |||
1769 | void RewriteForPHI(PHINode *PN, const LSRFixup &LF, | |||
1770 | const Formula &F, | |||
1771 | SCEVExpander &Rewriter, | |||
1772 | SmallVectorImpl<WeakVH> &DeadInsts, | |||
1773 | Pass *P) const; | |||
1774 | void Rewrite(const LSRFixup &LF, | |||
1775 | const Formula &F, | |||
1776 | SCEVExpander &Rewriter, | |||
1777 | SmallVectorImpl<WeakVH> &DeadInsts, | |||
1778 | Pass *P) const; | |||
1779 | void ImplementSolution(const SmallVectorImpl<const Formula *> &Solution, | |||
1780 | Pass *P); | |||
1781 | ||||
1782 | public: | |||
1783 | LSRInstance(Loop *L, Pass *P); | |||
1784 | ||||
1785 | bool getChanged() const { return Changed; } | |||
1786 | ||||
1787 | void print_factors_and_types(raw_ostream &OS) const; | |||
1788 | void print_fixups(raw_ostream &OS) const; | |||
1789 | void print_uses(raw_ostream &OS) const; | |||
1790 | void print(raw_ostream &OS) const; | |||
1791 | void dump() const; | |||
1792 | }; | |||
1793 | ||||
1794 | } | |||
1795 | ||||
1796 | /// OptimizeShadowIV - If IV is used in a int-to-float cast | |||
1797 | /// inside the loop then try to eliminate the cast operation. | |||
1798 | void LSRInstance::OptimizeShadowIV() { | |||
1799 | const SCEV *BackedgeTakenCount = SE.getBackedgeTakenCount(L); | |||
1800 | if (isa<SCEVCouldNotCompute>(BackedgeTakenCount)) | |||
1801 | return; | |||
1802 | ||||
1803 | for (IVUsers::const_iterator UI = IU.begin(), E = IU.end(); | |||
1804 | UI != E; /* empty */) { | |||
1805 | IVUsers::const_iterator CandidateUI = UI; | |||
1806 | ++UI; | |||
1807 | Instruction *ShadowUse = CandidateUI->getUser(); | |||
1808 | Type *DestTy = nullptr; | |||
1809 | bool IsSigned = false; | |||
1810 | ||||
1811 | /* If shadow use is a int->float cast then insert a second IV | |||
1812 | to eliminate this cast. | |||
1813 | ||||
1814 | for (unsigned i = 0; i < n; ++i) | |||
1815 | foo((double)i); | |||
1816 | ||||
1817 | is transformed into | |||
1818 | ||||
1819 | double d = 0.0; | |||
1820 | for (unsigned i = 0; i < n; ++i, ++d) | |||
1821 | foo(d); | |||
1822 | */ | |||
1823 | if (UIToFPInst *UCast = dyn_cast<UIToFPInst>(CandidateUI->getUser())) { | |||
1824 | IsSigned = false; | |||
1825 | DestTy = UCast->getDestTy(); | |||
1826 | } | |||
1827 | else if (SIToFPInst *SCast = dyn_cast<SIToFPInst>(CandidateUI->getUser())) { | |||
1828 | IsSigned = true; | |||
1829 | DestTy = SCast->getDestTy(); | |||
1830 | } | |||
1831 | if (!DestTy) continue; | |||
1832 | ||||
1833 | // If target does not support DestTy natively then do not apply | |||
1834 | // this transformation. | |||
1835 | if (!TTI.isTypeLegal(DestTy)) continue; | |||
1836 | ||||
1837 | PHINode *PH = dyn_cast<PHINode>(ShadowUse->getOperand(0)); | |||
1838 | if (!PH) continue; | |||
1839 | if (PH->getNumIncomingValues() != 2) continue; | |||
1840 | ||||
1841 | Type *SrcTy = PH->getType(); | |||
1842 | int Mantissa = DestTy->getFPMantissaWidth(); | |||
1843 | if (Mantissa == -1) continue; | |||
1844 | if ((int)SE.getTypeSizeInBits(SrcTy) > Mantissa) | |||
1845 | continue; | |||
1846 | ||||
1847 | unsigned Entry, Latch; | |||
1848 | if (PH->getIncomingBlock(0) == L->getLoopPreheader()) { | |||
1849 | Entry = 0; | |||
1850 | Latch = 1; | |||
1851 | } else { | |||
1852 | Entry = 1; | |||
1853 | Latch = 0; | |||
1854 | } | |||
1855 | ||||
1856 | ConstantInt *Init = dyn_cast<ConstantInt>(PH->getIncomingValue(Entry)); | |||
1857 | if (!Init) continue; | |||
1858 | Constant *NewInit = ConstantFP::get(DestTy, IsSigned ? | |||
1859 | (double)Init->getSExtValue() : | |||
1860 | (double)Init->getZExtValue()); | |||
1861 | ||||
1862 | BinaryOperator *Incr = | |||
1863 | dyn_cast<BinaryOperator>(PH->getIncomingValue(Latch)); | |||
1864 | if (!Incr) continue; | |||
1865 | if (Incr->getOpcode() != Instruction::Add | |||
1866 | && Incr->getOpcode() != Instruction::Sub) | |||
1867 | continue; | |||
1868 | ||||
1869 | /* Initialize new IV, double d = 0.0 in above example. */ | |||
1870 | ConstantInt *C = nullptr; | |||
1871 | if (Incr->getOperand(0) == PH) | |||
1872 | C = dyn_cast<ConstantInt>(Incr->getOperand(1)); | |||
1873 | else if (Incr->getOperand(1) == PH) | |||
1874 | C = dyn_cast<ConstantInt>(Incr->getOperand(0)); | |||
1875 | else | |||
1876 | continue; | |||
1877 | ||||
1878 | if (!C) continue; | |||
1879 | ||||
1880 | // Ignore negative constants, as the code below doesn't handle them | |||
1881 | // correctly. TODO: Remove this restriction. | |||
1882 | if (!C->getValue().isStrictlyPositive()) continue; | |||
1883 | ||||
1884 | /* Add new PHINode. */ | |||
1885 | PHINode *NewPH = PHINode::Create(DestTy, 2, "IV.S.", PH); | |||
1886 | ||||
1887 | /* create new increment. '++d' in above example. */ | |||
1888 | Constant *CFP = ConstantFP::get(DestTy, C->getZExtValue()); | |||
1889 | BinaryOperator *NewIncr = | |||
1890 | BinaryOperator::Create(Incr->getOpcode() == Instruction::Add ? | |||
1891 | Instruction::FAdd : Instruction::FSub, | |||
1892 | NewPH, CFP, "IV.S.next.", Incr); | |||
1893 | ||||
1894 | NewPH->addIncoming(NewInit, PH->getIncomingBlock(Entry)); | |||
1895 | NewPH->addIncoming(NewIncr, PH->getIncomingBlock(Latch)); | |||
1896 | ||||
1897 | /* Remove cast operation */ | |||
1898 | ShadowUse->replaceAllUsesWith(NewPH); | |||
1899 | ShadowUse->eraseFromParent(); | |||
1900 | Changed = true; | |||
1901 | break; | |||
1902 | } | |||
1903 | } | |||
1904 | ||||
1905 | /// FindIVUserForCond - If Cond has an operand that is an expression of an IV, | |||
1906 | /// set the IV user and stride information and return true, otherwise return | |||
1907 | /// false. | |||
1908 | bool LSRInstance::FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse) { | |||
1909 | for (IVStrideUse &U : IU) | |||
1910 | if (U.getUser() == Cond) { | |||
1911 | // NOTE: we could handle setcc instructions with multiple uses here, but | |||
1912 | // InstCombine does it as well for simple uses, it's not clear that it | |||
1913 | // occurs enough in real life to handle. | |||
1914 | CondUse = &U; | |||
1915 | return true; | |||
1916 | } | |||
1917 | return false; | |||
1918 | } | |||
1919 | ||||
1920 | /// OptimizeMax - Rewrite the loop's terminating condition if it uses | |||
1921 | /// a max computation. | |||
1922 | /// | |||
1923 | /// This is a narrow solution to a specific, but acute, problem. For loops | |||
1924 | /// like this: | |||
1925 | /// | |||
1926 | /// i = 0; | |||
1927 | /// do { | |||
1928 | /// p[i] = 0.0; | |||
1929 | /// } while (++i < n); | |||
1930 | /// | |||
1931 | /// the trip count isn't just 'n', because 'n' might not be positive. And | |||
1932 | /// unfortunately this can come up even for loops where the user didn't use | |||
1933 | /// a C do-while loop. For example, seemingly well-behaved top-test loops | |||
1934 | /// will commonly be lowered like this: | |||
1935 | // | |||
1936 | /// if (n > 0) { | |||
1937 | /// i = 0; | |||
1938 | /// do { | |||
1939 | /// p[i] = 0.0; | |||
1940 | /// } while (++i < n); | |||
1941 | /// } | |||
1942 | /// | |||
1943 | /// and then it's possible for subsequent optimization to obscure the if | |||
1944 | /// test in such a way that indvars can't find it. | |||
1945 | /// | |||
1946 | /// When indvars can't find the if test in loops like this, it creates a | |||
1947 | /// max expression, which allows it to give the loop a canonical | |||
1948 | /// induction variable: | |||
1949 | /// | |||
1950 | /// i = 0; | |||
1951 | /// max = n < 1 ? 1 : n; | |||
1952 | /// do { | |||
1953 | /// p[i] = 0.0; | |||
1954 | /// } while (++i != max); | |||
1955 | /// | |||
1956 | /// Canonical induction variables are necessary because the loop passes | |||
1957 | /// are designed around them. The most obvious example of this is the | |||
1958 | /// LoopInfo analysis, which doesn't remember trip count values. It | |||
1959 | /// expects to be able to rediscover the trip count each time it is | |||
1960 | /// needed, and it does this using a simple analysis that only succeeds if | |||
1961 | /// the loop has a canonical induction variable. | |||
1962 | /// | |||
1963 | /// However, when it comes time to generate code, the maximum operation | |||
1964 | /// can be quite costly, especially if it's inside of an outer loop. | |||
1965 | /// | |||
1966 | /// This function solves this problem by detecting this type of loop and | |||
1967 | /// rewriting their conditions from ICMP_NE back to ICMP_SLT, and deleting | |||
1968 | /// the instructions for the maximum computation. | |||
1969 | /// | |||
1970 | ICmpInst *LSRInstance::OptimizeMax(ICmpInst *Cond, IVStrideUse* &CondUse) { | |||
1971 | // Check that the loop matches the pattern we're looking for. | |||
1972 | if (Cond->getPredicate() != CmpInst::ICMP_EQ && | |||
1973 | Cond->getPredicate() != CmpInst::ICMP_NE) | |||
1974 | return Cond; | |||
1975 | ||||
1976 | SelectInst *Sel = dyn_cast<SelectInst>(Cond->getOperand(1)); | |||
1977 | if (!Sel || !Sel->hasOneUse()) return Cond; | |||
1978 | ||||
1979 | const SCEV *BackedgeTakenCount = SE.getBackedgeTakenCount(L); | |||
1980 | if (isa<SCEVCouldNotCompute>(BackedgeTakenCount)) | |||
1981 | return Cond; | |||
1982 | const SCEV *One = SE.getConstant(BackedgeTakenCount->getType(), 1); | |||
1983 | ||||
1984 | // Add one to the backedge-taken count to get the trip count. | |||
1985 | const SCEV *IterationCount = SE.getAddExpr(One, BackedgeTakenCount); | |||
1986 | if (IterationCount != SE.getSCEV(Sel)) return Cond; | |||
1987 | ||||
1988 | // Check for a max calculation that matches the pattern. There's no check | |||
1989 | // for ICMP_ULE here because the comparison would be with zero, which | |||
1990 | // isn't interesting. | |||
1991 | CmpInst::Predicate Pred = ICmpInst::BAD_ICMP_PREDICATE; | |||
1992 | const SCEVNAryExpr *Max = nullptr; | |||
1993 | if (const SCEVSMaxExpr *S = dyn_cast<SCEVSMaxExpr>(BackedgeTakenCount)) { | |||
1994 | Pred = ICmpInst::ICMP_SLE; | |||
1995 | Max = S; | |||
1996 | } else if (const SCEVSMaxExpr *S = dyn_cast<SCEVSMaxExpr>(IterationCount)) { | |||
1997 | Pred = ICmpInst::ICMP_SLT; | |||
1998 | Max = S; | |||
1999 | } else if (const SCEVUMaxExpr *U = dyn_cast<SCEVUMaxExpr>(IterationCount)) { | |||
2000 | Pred = ICmpInst::ICMP_ULT; | |||
2001 | Max = U; | |||
2002 | } else { | |||
2003 | // No match; bail. | |||
2004 | return Cond; | |||
2005 | } | |||
2006 | ||||
2007 | // To handle a max with more than two operands, this optimization would | |||
2008 | // require additional checking and setup. | |||
2009 | if (Max->getNumOperands() != 2) | |||
2010 | return Cond; | |||
2011 | ||||
2012 | const SCEV *MaxLHS = Max->getOperand(0); | |||
2013 | const SCEV *MaxRHS = Max->getOperand(1); | |||
2014 | ||||
2015 | // ScalarEvolution canonicalizes constants to the left. For < and >, look | |||
2016 | // for a comparison with 1. For <= and >=, a comparison with zero. | |||
2017 | if (!MaxLHS || | |||
2018 | (ICmpInst::isTrueWhenEqual(Pred) ? !MaxLHS->isZero() : (MaxLHS != One))) | |||
2019 | return Cond; | |||
2020 | ||||
2021 | // Check the relevant induction variable for conformance to | |||
2022 | // the pattern. | |||
2023 | const SCEV *IV = SE.getSCEV(Cond->getOperand(0)); | |||
2024 | const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(IV); | |||
2025 | if (!AR || !AR->isAffine() || | |||
2026 | AR->getStart() != One || | |||
2027 | AR->getStepRecurrence(SE) != One) | |||
2028 | return Cond; | |||
2029 | ||||
2030 | assert(AR->getLoop() == L &&((AR->getLoop() == L && "Loop condition operand is an addrec in a different loop!" ) ? static_cast<void> (0) : __assert_fail ("AR->getLoop() == L && \"Loop condition operand is an addrec in a different loop!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2031, __PRETTY_FUNCTION__)) | |||
2031 | "Loop condition operand is an addrec in a different loop!")((AR->getLoop() == L && "Loop condition operand is an addrec in a different loop!" ) ? static_cast<void> (0) : __assert_fail ("AR->getLoop() == L && \"Loop condition operand is an addrec in a different loop!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2031, __PRETTY_FUNCTION__)); | |||
2032 | ||||
2033 | // Check the right operand of the select, and remember it, as it will | |||
2034 | // be used in the new comparison instruction. | |||
2035 | Value *NewRHS = nullptr; | |||
2036 | if (ICmpInst::isTrueWhenEqual(Pred)) { | |||
2037 | // Look for n+1, and grab n. | |||
2038 | if (AddOperator *BO = dyn_cast<AddOperator>(Sel->getOperand(1))) | |||
2039 | if (ConstantInt *BO1 = dyn_cast<ConstantInt>(BO->getOperand(1))) | |||
2040 | if (BO1->isOne() && SE.getSCEV(BO->getOperand(0)) == MaxRHS) | |||
2041 | NewRHS = BO->getOperand(0); | |||
2042 | if (AddOperator *BO = dyn_cast<AddOperator>(Sel->getOperand(2))) | |||
2043 | if (ConstantInt *BO1 = dyn_cast<ConstantInt>(BO->getOperand(1))) | |||
2044 | if (BO1->isOne() && SE.getSCEV(BO->getOperand(0)) == MaxRHS) | |||
2045 | NewRHS = BO->getOperand(0); | |||
2046 | if (!NewRHS) | |||
2047 | return Cond; | |||
2048 | } else if (SE.getSCEV(Sel->getOperand(1)) == MaxRHS) | |||
2049 | NewRHS = Sel->getOperand(1); | |||
2050 | else if (SE.getSCEV(Sel->getOperand(2)) == MaxRHS) | |||
2051 | NewRHS = Sel->getOperand(2); | |||
2052 | else if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(MaxRHS)) | |||
2053 | NewRHS = SU->getValue(); | |||
2054 | else | |||
2055 | // Max doesn't match expected pattern. | |||
2056 | return Cond; | |||
2057 | ||||
2058 | // Determine the new comparison opcode. It may be signed or unsigned, | |||
2059 | // and the original comparison may be either equality or inequality. | |||
2060 | if (Cond->getPredicate() == CmpInst::ICMP_EQ) | |||
2061 | Pred = CmpInst::getInversePredicate(Pred); | |||
2062 | ||||
2063 | // Ok, everything looks ok to change the condition into an SLT or SGE and | |||
2064 | // delete the max calculation. | |||
2065 | ICmpInst *NewCond = | |||
2066 | new ICmpInst(Cond, Pred, Cond->getOperand(0), NewRHS, "scmp"); | |||
2067 | ||||
2068 | // Delete the max calculation instructions. | |||
2069 | Cond->replaceAllUsesWith(NewCond); | |||
2070 | CondUse->setUser(NewCond); | |||
2071 | Instruction *Cmp = cast<Instruction>(Sel->getOperand(0)); | |||
2072 | Cond->eraseFromParent(); | |||
2073 | Sel->eraseFromParent(); | |||
2074 | if (Cmp->use_empty()) | |||
2075 | Cmp->eraseFromParent(); | |||
2076 | return NewCond; | |||
2077 | } | |||
2078 | ||||
2079 | /// OptimizeLoopTermCond - Change loop terminating condition to use the | |||
2080 | /// postinc iv when possible. | |||
2081 | void | |||
2082 | LSRInstance::OptimizeLoopTermCond() { | |||
2083 | SmallPtrSet<Instruction *, 4> PostIncs; | |||
2084 | ||||
2085 | BasicBlock *LatchBlock = L->getLoopLatch(); | |||
2086 | SmallVector<BasicBlock*, 8> ExitingBlocks; | |||
2087 | L->getExitingBlocks(ExitingBlocks); | |||
2088 | ||||
2089 | for (BasicBlock *ExitingBlock : ExitingBlocks) { | |||
2090 | ||||
2091 | // Get the terminating condition for the loop if possible. If we | |||
2092 | // can, we want to change it to use a post-incremented version of its | |||
2093 | // induction variable, to allow coalescing the live ranges for the IV into | |||
2094 | // one register value. | |||
2095 | ||||
2096 | BranchInst *TermBr = dyn_cast<BranchInst>(ExitingBlock->getTerminator()); | |||
2097 | if (!TermBr) | |||
2098 | continue; | |||
2099 | // FIXME: Overly conservative, termination condition could be an 'or' etc.. | |||
2100 | if (TermBr->isUnconditional() || !isa<ICmpInst>(TermBr->getCondition())) | |||
2101 | continue; | |||
2102 | ||||
2103 | // Search IVUsesByStride to find Cond's IVUse if there is one. | |||
2104 | IVStrideUse *CondUse = nullptr; | |||
2105 | ICmpInst *Cond = cast<ICmpInst>(TermBr->getCondition()); | |||
2106 | if (!FindIVUserForCond(Cond, CondUse)) | |||
2107 | continue; | |||
2108 | ||||
2109 | // If the trip count is computed in terms of a max (due to ScalarEvolution | |||
2110 | // being unable to find a sufficient guard, for example), change the loop | |||
2111 | // comparison to use SLT or ULT instead of NE. | |||
2112 | // One consequence of doing this now is that it disrupts the count-down | |||
2113 | // optimization. That's not always a bad thing though, because in such | |||
2114 | // cases it may still be worthwhile to avoid a max. | |||
2115 | Cond = OptimizeMax(Cond, CondUse); | |||
2116 | ||||
2117 | // If this exiting block dominates the latch block, it may also use | |||
2118 | // the post-inc value if it won't be shared with other uses. | |||
2119 | // Check for dominance. | |||
2120 | if (!DT.dominates(ExitingBlock, LatchBlock)) | |||
2121 | continue; | |||
2122 | ||||
2123 | // Conservatively avoid trying to use the post-inc value in non-latch | |||
2124 | // exits if there may be pre-inc users in intervening blocks. | |||
2125 | if (LatchBlock != ExitingBlock) | |||
2126 | for (IVUsers::const_iterator UI = IU.begin(), E = IU.end(); UI != E; ++UI) | |||
2127 | // Test if the use is reachable from the exiting block. This dominator | |||
2128 | // query is a conservative approximation of reachability. | |||
2129 | if (&*UI != CondUse && | |||
2130 | !DT.properlyDominates(UI->getUser()->getParent(), ExitingBlock)) { | |||
2131 | // Conservatively assume there may be reuse if the quotient of their | |||
2132 | // strides could be a legal scale. | |||
2133 | const SCEV *A = IU.getStride(*CondUse, L); | |||
2134 | const SCEV *B = IU.getStride(*UI, L); | |||
2135 | if (!A || !B) continue; | |||
2136 | if (SE.getTypeSizeInBits(A->getType()) != | |||
2137 | SE.getTypeSizeInBits(B->getType())) { | |||
2138 | if (SE.getTypeSizeInBits(A->getType()) > | |||
2139 | SE.getTypeSizeInBits(B->getType())) | |||
2140 | B = SE.getSignExtendExpr(B, A->getType()); | |||
2141 | else | |||
2142 | A = SE.getSignExtendExpr(A, B->getType()); | |||
2143 | } | |||
2144 | if (const SCEVConstant *D = | |||
2145 | dyn_cast_or_null<SCEVConstant>(getExactSDiv(B, A, SE))) { | |||
2146 | const ConstantInt *C = D->getValue(); | |||
2147 | // Stride of one or negative one can have reuse with non-addresses. | |||
2148 | if (C->isOne() || C->isAllOnesValue()) | |||
2149 | goto decline_post_inc; | |||
2150 | // Avoid weird situations. | |||
2151 | if (C->getValue().getMinSignedBits() >= 64 || | |||
2152 | C->getValue().isMinSignedValue()) | |||
2153 | goto decline_post_inc; | |||
2154 | // Check for possible scaled-address reuse. | |||
2155 | Type *AccessTy = getAccessType(UI->getUser()); | |||
2156 | int64_t Scale = C->getSExtValue(); | |||
2157 | if (TTI.isLegalAddressingMode(AccessTy, /*BaseGV=*/ nullptr, | |||
2158 | /*BaseOffset=*/ 0, | |||
2159 | /*HasBaseReg=*/ false, Scale)) | |||
2160 | goto decline_post_inc; | |||
2161 | Scale = -Scale; | |||
2162 | if (TTI.isLegalAddressingMode(AccessTy, /*BaseGV=*/ nullptr, | |||
2163 | /*BaseOffset=*/ 0, | |||
2164 | /*HasBaseReg=*/ false, Scale)) | |||
2165 | goto decline_post_inc; | |||
2166 | } | |||
2167 | } | |||
2168 | ||||
2169 | DEBUG(dbgs() << " Change loop exiting icmp to use postinc iv: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Change loop exiting icmp to use postinc iv: " << *Cond << '\n'; } } while (0) | |||
2170 | << *Cond << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Change loop exiting icmp to use postinc iv: " << *Cond << '\n'; } } while (0); | |||
2171 | ||||
2172 | // It's possible for the setcc instruction to be anywhere in the loop, and | |||
2173 | // possible for it to have multiple users. If it is not immediately before | |||
2174 | // the exiting block branch, move it. | |||
2175 | if (&*++BasicBlock::iterator(Cond) != TermBr) { | |||
2176 | if (Cond->hasOneUse()) { | |||
2177 | Cond->moveBefore(TermBr); | |||
2178 | } else { | |||
2179 | // Clone the terminating condition and insert into the loopend. | |||
2180 | ICmpInst *OldCond = Cond; | |||
2181 | Cond = cast<ICmpInst>(Cond->clone()); | |||
2182 | Cond->setName(L->getHeader()->getName() + ".termcond"); | |||
2183 | ExitingBlock->getInstList().insert(TermBr, Cond); | |||
2184 | ||||
2185 | // Clone the IVUse, as the old use still exists! | |||
2186 | CondUse = &IU.AddUser(Cond, CondUse->getOperandValToReplace()); | |||
2187 | TermBr->replaceUsesOfWith(OldCond, Cond); | |||
2188 | } | |||
2189 | } | |||
2190 | ||||
2191 | // If we get to here, we know that we can transform the setcc instruction to | |||
2192 | // use the post-incremented version of the IV, allowing us to coalesce the | |||
2193 | // live ranges for the IV correctly. | |||
2194 | CondUse->transformToPostInc(L); | |||
2195 | Changed = true; | |||
2196 | ||||
2197 | PostIncs.insert(Cond); | |||
2198 | decline_post_inc:; | |||
2199 | } | |||
2200 | ||||
2201 | // Determine an insertion point for the loop induction variable increment. It | |||
2202 | // must dominate all the post-inc comparisons we just set up, and it must | |||
2203 | // dominate the loop latch edge. | |||
2204 | IVIncInsertPos = L->getLoopLatch()->getTerminator(); | |||
2205 | for (Instruction *Inst : PostIncs) { | |||
2206 | BasicBlock *BB = | |||
2207 | DT.findNearestCommonDominator(IVIncInsertPos->getParent(), | |||
2208 | Inst->getParent()); | |||
2209 | if (BB == Inst->getParent()) | |||
2210 | IVIncInsertPos = Inst; | |||
2211 | else if (BB != IVIncInsertPos->getParent()) | |||
2212 | IVIncInsertPos = BB->getTerminator(); | |||
2213 | } | |||
2214 | } | |||
2215 | ||||
2216 | /// reconcileNewOffset - Determine if the given use can accommodate a fixup | |||
2217 | /// at the given offset and other details. If so, update the use and | |||
2218 | /// return true. | |||
2219 | bool | |||
2220 | LSRInstance::reconcileNewOffset(LSRUse &LU, int64_t NewOffset, bool HasBaseReg, | |||
2221 | LSRUse::KindType Kind, Type *AccessTy) { | |||
2222 | int64_t NewMinOffset = LU.MinOffset; | |||
2223 | int64_t NewMaxOffset = LU.MaxOffset; | |||
2224 | Type *NewAccessTy = AccessTy; | |||
2225 | ||||
2226 | // Check for a mismatched kind. It's tempting to collapse mismatched kinds to | |||
2227 | // something conservative, however this can pessimize in the case that one of | |||
2228 | // the uses will have all its uses outside the loop, for example. | |||
2229 | if (LU.Kind != Kind) | |||
2230 | return false; | |||
2231 | ||||
2232 | // Check for a mismatched access type, and fall back conservatively as needed. | |||
2233 | // TODO: Be less conservative when the type is similar and can use the same | |||
2234 | // addressing modes. | |||
2235 | if (Kind == LSRUse::Address && AccessTy != LU.AccessTy) | |||
2236 | NewAccessTy = Type::getVoidTy(AccessTy->getContext()); | |||
2237 | ||||
2238 | // Conservatively assume HasBaseReg is true for now. | |||
2239 | if (NewOffset < LU.MinOffset) { | |||
2240 | if (!isAlwaysFoldable(TTI, Kind, NewAccessTy, /*BaseGV=*/nullptr, | |||
2241 | LU.MaxOffset - NewOffset, HasBaseReg)) | |||
2242 | return false; | |||
2243 | NewMinOffset = NewOffset; | |||
2244 | } else if (NewOffset > LU.MaxOffset) { | |||
2245 | if (!isAlwaysFoldable(TTI, Kind, NewAccessTy, /*BaseGV=*/nullptr, | |||
2246 | NewOffset - LU.MinOffset, HasBaseReg)) | |||
2247 | return false; | |||
2248 | NewMaxOffset = NewOffset; | |||
2249 | } | |||
2250 | ||||
2251 | // Update the use. | |||
2252 | LU.MinOffset = NewMinOffset; | |||
2253 | LU.MaxOffset = NewMaxOffset; | |||
2254 | LU.AccessTy = NewAccessTy; | |||
2255 | if (NewOffset != LU.Offsets.back()) | |||
2256 | LU.Offsets.push_back(NewOffset); | |||
2257 | return true; | |||
2258 | } | |||
2259 | ||||
2260 | /// getUse - Return an LSRUse index and an offset value for a fixup which | |||
2261 | /// needs the given expression, with the given kind and optional access type. | |||
2262 | /// Either reuse an existing use or create a new one, as needed. | |||
2263 | std::pair<size_t, int64_t> | |||
2264 | LSRInstance::getUse(const SCEV *&Expr, | |||
2265 | LSRUse::KindType Kind, Type *AccessTy) { | |||
2266 | const SCEV *Copy = Expr; | |||
2267 | int64_t Offset = ExtractImmediate(Expr, SE); | |||
2268 | ||||
2269 | // Basic uses can't accept any offset, for example. | |||
2270 | if (!isAlwaysFoldable(TTI, Kind, AccessTy, /*BaseGV=*/ nullptr, | |||
2271 | Offset, /*HasBaseReg=*/ true)) { | |||
2272 | Expr = Copy; | |||
2273 | Offset = 0; | |||
2274 | } | |||
2275 | ||||
2276 | std::pair<UseMapTy::iterator, bool> P = | |||
2277 | UseMap.insert(std::make_pair(LSRUse::SCEVUseKindPair(Expr, Kind), 0)); | |||
2278 | if (!P.second) { | |||
2279 | // A use already existed with this base. | |||
2280 | size_t LUIdx = P.first->second; | |||
2281 | LSRUse &LU = Uses[LUIdx]; | |||
2282 | if (reconcileNewOffset(LU, Offset, /*HasBaseReg=*/true, Kind, AccessTy)) | |||
2283 | // Reuse this use. | |||
2284 | return std::make_pair(LUIdx, Offset); | |||
2285 | } | |||
2286 | ||||
2287 | // Create a new use. | |||
2288 | size_t LUIdx = Uses.size(); | |||
2289 | P.first->second = LUIdx; | |||
2290 | Uses.push_back(LSRUse(Kind, AccessTy)); | |||
2291 | LSRUse &LU = Uses[LUIdx]; | |||
2292 | ||||
2293 | // We don't need to track redundant offsets, but we don't need to go out | |||
2294 | // of our way here to avoid them. | |||
2295 | if (LU.Offsets.empty() || Offset != LU.Offsets.back()) | |||
2296 | LU.Offsets.push_back(Offset); | |||
2297 | ||||
2298 | LU.MinOffset = Offset; | |||
2299 | LU.MaxOffset = Offset; | |||
2300 | return std::make_pair(LUIdx, Offset); | |||
2301 | } | |||
2302 | ||||
2303 | /// DeleteUse - Delete the given use from the Uses list. | |||
2304 | void LSRInstance::DeleteUse(LSRUse &LU, size_t LUIdx) { | |||
2305 | if (&LU != &Uses.back()) | |||
2306 | std::swap(LU, Uses.back()); | |||
2307 | Uses.pop_back(); | |||
2308 | ||||
2309 | // Update RegUses. | |||
2310 | RegUses.SwapAndDropUse(LUIdx, Uses.size()); | |||
2311 | } | |||
2312 | ||||
2313 | /// FindUseWithFormula - Look for a use distinct from OrigLU which is has | |||
2314 | /// a formula that has the same registers as the given formula. | |||
2315 | LSRUse * | |||
2316 | LSRInstance::FindUseWithSimilarFormula(const Formula &OrigF, | |||
2317 | const LSRUse &OrigLU) { | |||
2318 | // Search all uses for the formula. This could be more clever. | |||
2319 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
2320 | LSRUse &LU = Uses[LUIdx]; | |||
2321 | // Check whether this use is close enough to OrigLU, to see whether it's | |||
2322 | // worthwhile looking through its formulae. | |||
2323 | // Ignore ICmpZero uses because they may contain formulae generated by | |||
2324 | // GenerateICmpZeroScales, in which case adding fixup offsets may | |||
2325 | // be invalid. | |||
2326 | if (&LU != &OrigLU && | |||
2327 | LU.Kind != LSRUse::ICmpZero && | |||
2328 | LU.Kind == OrigLU.Kind && OrigLU.AccessTy == LU.AccessTy && | |||
2329 | LU.WidestFixupType == OrigLU.WidestFixupType && | |||
2330 | LU.HasFormulaWithSameRegs(OrigF)) { | |||
2331 | // Scan through this use's formulae. | |||
2332 | for (const Formula &F : LU.Formulae) { | |||
2333 | // Check to see if this formula has the same registers and symbols | |||
2334 | // as OrigF. | |||
2335 | if (F.BaseRegs == OrigF.BaseRegs && | |||
2336 | F.ScaledReg == OrigF.ScaledReg && | |||
2337 | F.BaseGV == OrigF.BaseGV && | |||
2338 | F.Scale == OrigF.Scale && | |||
2339 | F.UnfoldedOffset == OrigF.UnfoldedOffset) { | |||
2340 | if (F.BaseOffset == 0) | |||
2341 | return &LU; | |||
2342 | // This is the formula where all the registers and symbols matched; | |||
2343 | // there aren't going to be any others. Since we declined it, we | |||
2344 | // can skip the rest of the formulae and proceed to the next LSRUse. | |||
2345 | break; | |||
2346 | } | |||
2347 | } | |||
2348 | } | |||
2349 | } | |||
2350 | ||||
2351 | // Nothing looked good. | |||
2352 | return nullptr; | |||
2353 | } | |||
2354 | ||||
2355 | void LSRInstance::CollectInterestingTypesAndFactors() { | |||
2356 | SmallSetVector<const SCEV *, 4> Strides; | |||
2357 | ||||
2358 | // Collect interesting types and strides. | |||
2359 | SmallVector<const SCEV *, 4> Worklist; | |||
2360 | for (const IVStrideUse &U : IU) { | |||
2361 | const SCEV *Expr = IU.getExpr(U); | |||
2362 | ||||
2363 | // Collect interesting types. | |||
2364 | Types.insert(SE.getEffectiveSCEVType(Expr->getType())); | |||
2365 | ||||
2366 | // Add strides for mentioned loops. | |||
2367 | Worklist.push_back(Expr); | |||
2368 | do { | |||
2369 | const SCEV *S = Worklist.pop_back_val(); | |||
2370 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) { | |||
2371 | if (AR->getLoop() == L) | |||
2372 | Strides.insert(AR->getStepRecurrence(SE)); | |||
2373 | Worklist.push_back(AR->getStart()); | |||
2374 | } else if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | |||
2375 | Worklist.append(Add->op_begin(), Add->op_end()); | |||
2376 | } | |||
2377 | } while (!Worklist.empty()); | |||
2378 | } | |||
2379 | ||||
2380 | // Compute interesting factors from the set of interesting strides. | |||
2381 | for (SmallSetVector<const SCEV *, 4>::const_iterator | |||
2382 | I = Strides.begin(), E = Strides.end(); I != E; ++I) | |||
2383 | for (SmallSetVector<const SCEV *, 4>::const_iterator NewStrideIter = | |||
2384 | std::next(I); NewStrideIter != E; ++NewStrideIter) { | |||
2385 | const SCEV *OldStride = *I; | |||
2386 | const SCEV *NewStride = *NewStrideIter; | |||
2387 | ||||
2388 | if (SE.getTypeSizeInBits(OldStride->getType()) != | |||
2389 | SE.getTypeSizeInBits(NewStride->getType())) { | |||
2390 | if (SE.getTypeSizeInBits(OldStride->getType()) > | |||
2391 | SE.getTypeSizeInBits(NewStride->getType())) | |||
2392 | NewStride = SE.getSignExtendExpr(NewStride, OldStride->getType()); | |||
2393 | else | |||
2394 | OldStride = SE.getSignExtendExpr(OldStride, NewStride->getType()); | |||
2395 | } | |||
2396 | if (const SCEVConstant *Factor = | |||
2397 | dyn_cast_or_null<SCEVConstant>(getExactSDiv(NewStride, OldStride, | |||
2398 | SE, true))) { | |||
2399 | if (Factor->getValue()->getValue().getMinSignedBits() <= 64) | |||
2400 | Factors.insert(Factor->getValue()->getValue().getSExtValue()); | |||
2401 | } else if (const SCEVConstant *Factor = | |||
2402 | dyn_cast_or_null<SCEVConstant>(getExactSDiv(OldStride, | |||
2403 | NewStride, | |||
2404 | SE, true))) { | |||
2405 | if (Factor->getValue()->getValue().getMinSignedBits() <= 64) | |||
2406 | Factors.insert(Factor->getValue()->getValue().getSExtValue()); | |||
2407 | } | |||
2408 | } | |||
2409 | ||||
2410 | // If all uses use the same type, don't bother looking for truncation-based | |||
2411 | // reuse. | |||
2412 | if (Types.size() == 1) | |||
2413 | Types.clear(); | |||
2414 | ||||
2415 | DEBUG(print_factors_and_types(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { print_factors_and_types(dbgs()); } } while (0); | |||
2416 | } | |||
2417 | ||||
2418 | /// findIVOperand - Helper for CollectChains that finds an IV operand (computed | |||
2419 | /// by an AddRec in this loop) within [OI,OE) or returns OE. If IVUsers mapped | |||
2420 | /// Instructions to IVStrideUses, we could partially skip this. | |||
2421 | static User::op_iterator | |||
2422 | findIVOperand(User::op_iterator OI, User::op_iterator OE, | |||
2423 | Loop *L, ScalarEvolution &SE) { | |||
2424 | for(; OI != OE; ++OI) { | |||
2425 | if (Instruction *Oper = dyn_cast<Instruction>(*OI)) { | |||
2426 | if (!SE.isSCEVable(Oper->getType())) | |||
2427 | continue; | |||
2428 | ||||
2429 | if (const SCEVAddRecExpr *AR = | |||
2430 | dyn_cast<SCEVAddRecExpr>(SE.getSCEV(Oper))) { | |||
2431 | if (AR->getLoop() == L) | |||
2432 | break; | |||
2433 | } | |||
2434 | } | |||
2435 | } | |||
2436 | return OI; | |||
2437 | } | |||
2438 | ||||
2439 | /// getWideOperand - IVChain logic must consistenctly peek base TruncInst | |||
2440 | /// operands, so wrap it in a convenient helper. | |||
2441 | static Value *getWideOperand(Value *Oper) { | |||
2442 | if (TruncInst *Trunc = dyn_cast<TruncInst>(Oper)) | |||
2443 | return Trunc->getOperand(0); | |||
2444 | return Oper; | |||
2445 | } | |||
2446 | ||||
2447 | /// isCompatibleIVType - Return true if we allow an IV chain to include both | |||
2448 | /// types. | |||
2449 | static bool isCompatibleIVType(Value *LVal, Value *RVal) { | |||
2450 | Type *LType = LVal->getType(); | |||
2451 | Type *RType = RVal->getType(); | |||
2452 | return (LType == RType) || (LType->isPointerTy() && RType->isPointerTy()); | |||
2453 | } | |||
2454 | ||||
2455 | /// getExprBase - Return an approximation of this SCEV expression's "base", or | |||
2456 | /// NULL for any constant. Returning the expression itself is | |||
2457 | /// conservative. Returning a deeper subexpression is more precise and valid as | |||
2458 | /// long as it isn't less complex than another subexpression. For expressions | |||
2459 | /// involving multiple unscaled values, we need to return the pointer-type | |||
2460 | /// SCEVUnknown. This avoids forming chains across objects, such as: | |||
2461 | /// PrevOper==a[i], IVOper==b[i], IVInc==b-a. | |||
2462 | /// | |||
2463 | /// Since SCEVUnknown is the rightmost type, and pointers are the rightmost | |||
2464 | /// SCEVUnknown, we simply return the rightmost SCEV operand. | |||
2465 | static const SCEV *getExprBase(const SCEV *S) { | |||
2466 | switch (S->getSCEVType()) { | |||
2467 | default: // uncluding scUnknown. | |||
2468 | return S; | |||
2469 | case scConstant: | |||
2470 | return nullptr; | |||
2471 | case scTruncate: | |||
2472 | return getExprBase(cast<SCEVTruncateExpr>(S)->getOperand()); | |||
2473 | case scZeroExtend: | |||
2474 | return getExprBase(cast<SCEVZeroExtendExpr>(S)->getOperand()); | |||
2475 | case scSignExtend: | |||
2476 | return getExprBase(cast<SCEVSignExtendExpr>(S)->getOperand()); | |||
2477 | case scAddExpr: { | |||
2478 | // Skip over scaled operands (scMulExpr) to follow add operands as long as | |||
2479 | // there's nothing more complex. | |||
2480 | // FIXME: not sure if we want to recognize negation. | |||
2481 | const SCEVAddExpr *Add = cast<SCEVAddExpr>(S); | |||
2482 | for (std::reverse_iterator<SCEVAddExpr::op_iterator> I(Add->op_end()), | |||
2483 | E(Add->op_begin()); I != E; ++I) { | |||
2484 | const SCEV *SubExpr = *I; | |||
2485 | if (SubExpr->getSCEVType() == scAddExpr) | |||
2486 | return getExprBase(SubExpr); | |||
2487 | ||||
2488 | if (SubExpr->getSCEVType() != scMulExpr) | |||
2489 | return SubExpr; | |||
2490 | } | |||
2491 | return S; // all operands are scaled, be conservative. | |||
2492 | } | |||
2493 | case scAddRecExpr: | |||
2494 | return getExprBase(cast<SCEVAddRecExpr>(S)->getStart()); | |||
2495 | } | |||
2496 | } | |||
2497 | ||||
2498 | /// Return true if the chain increment is profitable to expand into a loop | |||
2499 | /// invariant value, which may require its own register. A profitable chain | |||
2500 | /// increment will be an offset relative to the same base. We allow such offsets | |||
2501 | /// to potentially be used as chain increment as long as it's not obviously | |||
2502 | /// expensive to expand using real instructions. | |||
2503 | bool IVChain::isProfitableIncrement(const SCEV *OperExpr, | |||
2504 | const SCEV *IncExpr, | |||
2505 | ScalarEvolution &SE) { | |||
2506 | // Aggressively form chains when -stress-ivchain. | |||
2507 | if (StressIVChain) | |||
2508 | return true; | |||
2509 | ||||
2510 | // Do not replace a constant offset from IV head with a nonconstant IV | |||
2511 | // increment. | |||
2512 | if (!isa<SCEVConstant>(IncExpr)) { | |||
2513 | const SCEV *HeadExpr = SE.getSCEV(getWideOperand(Incs[0].IVOperand)); | |||
2514 | if (isa<SCEVConstant>(SE.getMinusSCEV(OperExpr, HeadExpr))) | |||
2515 | return 0; | |||
2516 | } | |||
2517 | ||||
2518 | SmallPtrSet<const SCEV*, 8> Processed; | |||
2519 | return !isHighCostExpansion(IncExpr, Processed, SE); | |||
2520 | } | |||
2521 | ||||
2522 | /// Return true if the number of registers needed for the chain is estimated to | |||
2523 | /// be less than the number required for the individual IV users. First prohibit | |||
2524 | /// any IV users that keep the IV live across increments (the Users set should | |||
2525 | /// be empty). Next count the number and type of increments in the chain. | |||
2526 | /// | |||
2527 | /// Chaining IVs can lead to considerable code bloat if ISEL doesn't | |||
2528 | /// effectively use postinc addressing modes. Only consider it profitable it the | |||
2529 | /// increments can be computed in fewer registers when chained. | |||
2530 | /// | |||
2531 | /// TODO: Consider IVInc free if it's already used in another chains. | |||
2532 | static bool | |||
2533 | isProfitableChain(IVChain &Chain, SmallPtrSetImpl<Instruction*> &Users, | |||
2534 | ScalarEvolution &SE, const TargetTransformInfo &TTI) { | |||
2535 | if (StressIVChain) | |||
2536 | return true; | |||
2537 | ||||
2538 | if (!Chain.hasIncs()) | |||
2539 | return false; | |||
2540 | ||||
2541 | if (!Users.empty()) { | |||
2542 | DEBUG(dbgs() << "Chain: " << *Chain.Incs[0].UserInst << " users:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Chain: " << *Chain. Incs[0].UserInst << " users:\n"; for (Instruction *Inst : Users) { dbgs() << " " << *Inst << "\n" ; }; } } while (0) | |||
2543 | for (Instruction *Inst : Users) {do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Chain: " << *Chain. Incs[0].UserInst << " users:\n"; for (Instruction *Inst : Users) { dbgs() << " " << *Inst << "\n" ; }; } } while (0) | |||
2544 | dbgs() << " " << *Inst << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Chain: " << *Chain. Incs[0].UserInst << " users:\n"; for (Instruction *Inst : Users) { dbgs() << " " << *Inst << "\n" ; }; } } while (0) | |||
2545 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Chain: " << *Chain. Incs[0].UserInst << " users:\n"; for (Instruction *Inst : Users) { dbgs() << " " << *Inst << "\n" ; }; } } while (0); | |||
2546 | return false; | |||
2547 | } | |||
2548 | assert(!Chain.Incs.empty() && "empty IV chains are not allowed")((!Chain.Incs.empty() && "empty IV chains are not allowed" ) ? static_cast<void> (0) : __assert_fail ("!Chain.Incs.empty() && \"empty IV chains are not allowed\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2548, __PRETTY_FUNCTION__)); | |||
2549 | ||||
2550 | // The chain itself may require a register, so intialize cost to 1. | |||
2551 | int cost = 1; | |||
2552 | ||||
2553 | // A complete chain likely eliminates the need for keeping the original IV in | |||
2554 | // a register. LSR does not currently know how to form a complete chain unless | |||
2555 | // the header phi already exists. | |||
2556 | if (isa<PHINode>(Chain.tailUserInst()) | |||
2557 | && SE.getSCEV(Chain.tailUserInst()) == Chain.Incs[0].IncExpr) { | |||
2558 | --cost; | |||
2559 | } | |||
2560 | const SCEV *LastIncExpr = nullptr; | |||
2561 | unsigned NumConstIncrements = 0; | |||
2562 | unsigned NumVarIncrements = 0; | |||
2563 | unsigned NumReusedIncrements = 0; | |||
2564 | for (const IVInc &Inc : Chain) { | |||
2565 | if (Inc.IncExpr->isZero()) | |||
2566 | continue; | |||
2567 | ||||
2568 | // Incrementing by zero or some constant is neutral. We assume constants can | |||
2569 | // be folded into an addressing mode or an add's immediate operand. | |||
2570 | if (isa<SCEVConstant>(Inc.IncExpr)) { | |||
2571 | ++NumConstIncrements; | |||
2572 | continue; | |||
2573 | } | |||
2574 | ||||
2575 | if (Inc.IncExpr == LastIncExpr) | |||
2576 | ++NumReusedIncrements; | |||
2577 | else | |||
2578 | ++NumVarIncrements; | |||
2579 | ||||
2580 | LastIncExpr = Inc.IncExpr; | |||
2581 | } | |||
2582 | // An IV chain with a single increment is handled by LSR's postinc | |||
2583 | // uses. However, a chain with multiple increments requires keeping the IV's | |||
2584 | // value live longer than it needs to be if chained. | |||
2585 | if (NumConstIncrements > 1) | |||
2586 | --cost; | |||
2587 | ||||
2588 | // Materializing increment expressions in the preheader that didn't exist in | |||
2589 | // the original code may cost a register. For example, sign-extended array | |||
2590 | // indices can produce ridiculous increments like this: | |||
2591 | // IV + ((sext i32 (2 * %s) to i64) + (-1 * (sext i32 %s to i64))) | |||
2592 | cost += NumVarIncrements; | |||
2593 | ||||
2594 | // Reusing variable increments likely saves a register to hold the multiple of | |||
2595 | // the stride. | |||
2596 | cost -= NumReusedIncrements; | |||
2597 | ||||
2598 | DEBUG(dbgs() << "Chain: " << *Chain.Incs[0].UserInst << " Cost: " << costdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Chain: " << *Chain. Incs[0].UserInst << " Cost: " << cost << "\n" ; } } while (0) | |||
2599 | << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Chain: " << *Chain. Incs[0].UserInst << " Cost: " << cost << "\n" ; } } while (0); | |||
2600 | ||||
2601 | return cost < 0; | |||
2602 | } | |||
2603 | ||||
2604 | /// ChainInstruction - Add this IV user to an existing chain or make it the head | |||
2605 | /// of a new chain. | |||
2606 | void LSRInstance::ChainInstruction(Instruction *UserInst, Instruction *IVOper, | |||
2607 | SmallVectorImpl<ChainUsers> &ChainUsersVec) { | |||
2608 | // When IVs are used as types of varying widths, they are generally converted | |||
2609 | // to a wider type with some uses remaining narrow under a (free) trunc. | |||
2610 | Value *const NextIV = getWideOperand(IVOper); | |||
2611 | const SCEV *const OperExpr = SE.getSCEV(NextIV); | |||
2612 | const SCEV *const OperExprBase = getExprBase(OperExpr); | |||
2613 | ||||
2614 | // Visit all existing chains. Check if its IVOper can be computed as a | |||
2615 | // profitable loop invariant increment from the last link in the Chain. | |||
2616 | unsigned ChainIdx = 0, NChains = IVChainVec.size(); | |||
2617 | const SCEV *LastIncExpr = nullptr; | |||
2618 | for (; ChainIdx < NChains; ++ChainIdx) { | |||
2619 | IVChain &Chain = IVChainVec[ChainIdx]; | |||
2620 | ||||
2621 | // Prune the solution space aggressively by checking that both IV operands | |||
2622 | // are expressions that operate on the same unscaled SCEVUnknown. This | |||
2623 | // "base" will be canceled by the subsequent getMinusSCEV call. Checking | |||
2624 | // first avoids creating extra SCEV expressions. | |||
2625 | if (!StressIVChain && Chain.ExprBase != OperExprBase) | |||
2626 | continue; | |||
2627 | ||||
2628 | Value *PrevIV = getWideOperand(Chain.Incs.back().IVOperand); | |||
2629 | if (!isCompatibleIVType(PrevIV, NextIV)) | |||
2630 | continue; | |||
2631 | ||||
2632 | // A phi node terminates a chain. | |||
2633 | if (isa<PHINode>(UserInst) && isa<PHINode>(Chain.tailUserInst())) | |||
2634 | continue; | |||
2635 | ||||
2636 | // The increment must be loop-invariant so it can be kept in a register. | |||
2637 | const SCEV *PrevExpr = SE.getSCEV(PrevIV); | |||
2638 | const SCEV *IncExpr = SE.getMinusSCEV(OperExpr, PrevExpr); | |||
2639 | if (!SE.isLoopInvariant(IncExpr, L)) | |||
2640 | continue; | |||
2641 | ||||
2642 | if (Chain.isProfitableIncrement(OperExpr, IncExpr, SE)) { | |||
2643 | LastIncExpr = IncExpr; | |||
2644 | break; | |||
2645 | } | |||
2646 | } | |||
2647 | // If we haven't found a chain, create a new one, unless we hit the max. Don't | |||
2648 | // bother for phi nodes, because they must be last in the chain. | |||
2649 | if (ChainIdx == NChains) { | |||
2650 | if (isa<PHINode>(UserInst)) | |||
2651 | return; | |||
2652 | if (NChains >= MaxChains && !StressIVChain) { | |||
2653 | DEBUG(dbgs() << "IV Chain Limit\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "IV Chain Limit\n"; } } while (0); | |||
2654 | return; | |||
2655 | } | |||
2656 | LastIncExpr = OperExpr; | |||
2657 | // IVUsers may have skipped over sign/zero extensions. We don't currently | |||
2658 | // attempt to form chains involving extensions unless they can be hoisted | |||
2659 | // into this loop's AddRec. | |||
2660 | if (!isa<SCEVAddRecExpr>(LastIncExpr)) | |||
2661 | return; | |||
2662 | ++NChains; | |||
2663 | IVChainVec.push_back(IVChain(IVInc(UserInst, IVOper, LastIncExpr), | |||
2664 | OperExprBase)); | |||
2665 | ChainUsersVec.resize(NChains); | |||
2666 | DEBUG(dbgs() << "IV Chain#" << ChainIdx << " Head: (" << *UserInstdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "IV Chain#" << ChainIdx << " Head: (" << *UserInst << ") IV=" << *LastIncExpr << "\n"; } } while (0) | |||
2667 | << ") IV=" << *LastIncExpr << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "IV Chain#" << ChainIdx << " Head: (" << *UserInst << ") IV=" << *LastIncExpr << "\n"; } } while (0); | |||
2668 | } else { | |||
2669 | DEBUG(dbgs() << "IV Chain#" << ChainIdx << " Inc: (" << *UserInstdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "IV Chain#" << ChainIdx << " Inc: (" << *UserInst << ") IV+" << *LastIncExpr << "\n"; } } while (0) | |||
2670 | << ") IV+" << *LastIncExpr << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "IV Chain#" << ChainIdx << " Inc: (" << *UserInst << ") IV+" << *LastIncExpr << "\n"; } } while (0); | |||
2671 | // Add this IV user to the end of the chain. | |||
2672 | IVChainVec[ChainIdx].add(IVInc(UserInst, IVOper, LastIncExpr)); | |||
2673 | } | |||
2674 | IVChain &Chain = IVChainVec[ChainIdx]; | |||
2675 | ||||
2676 | SmallPtrSet<Instruction*,4> &NearUsers = ChainUsersVec[ChainIdx].NearUsers; | |||
2677 | // This chain's NearUsers become FarUsers. | |||
2678 | if (!LastIncExpr->isZero()) { | |||
2679 | ChainUsersVec[ChainIdx].FarUsers.insert(NearUsers.begin(), | |||
2680 | NearUsers.end()); | |||
2681 | NearUsers.clear(); | |||
2682 | } | |||
2683 | ||||
2684 | // All other uses of IVOperand become near uses of the chain. | |||
2685 | // We currently ignore intermediate values within SCEV expressions, assuming | |||
2686 | // they will eventually be used be the current chain, or can be computed | |||
2687 | // from one of the chain increments. To be more precise we could | |||
2688 | // transitively follow its user and only add leaf IV users to the set. | |||
2689 | for (User *U : IVOper->users()) { | |||
2690 | Instruction *OtherUse = dyn_cast<Instruction>(U); | |||
2691 | if (!OtherUse) | |||
2692 | continue; | |||
2693 | // Uses in the chain will no longer be uses if the chain is formed. | |||
2694 | // Include the head of the chain in this iteration (not Chain.begin()). | |||
2695 | IVChain::const_iterator IncIter = Chain.Incs.begin(); | |||
2696 | IVChain::const_iterator IncEnd = Chain.Incs.end(); | |||
2697 | for( ; IncIter != IncEnd; ++IncIter) { | |||
2698 | if (IncIter->UserInst == OtherUse) | |||
2699 | break; | |||
2700 | } | |||
2701 | if (IncIter != IncEnd) | |||
2702 | continue; | |||
2703 | ||||
2704 | if (SE.isSCEVable(OtherUse->getType()) | |||
2705 | && !isa<SCEVUnknown>(SE.getSCEV(OtherUse)) | |||
2706 | && IU.isIVUserOrOperand(OtherUse)) { | |||
2707 | continue; | |||
2708 | } | |||
2709 | NearUsers.insert(OtherUse); | |||
2710 | } | |||
2711 | ||||
2712 | // Since this user is part of the chain, it's no longer considered a use | |||
2713 | // of the chain. | |||
2714 | ChainUsersVec[ChainIdx].FarUsers.erase(UserInst); | |||
2715 | } | |||
2716 | ||||
2717 | /// CollectChains - Populate the vector of Chains. | |||
2718 | /// | |||
2719 | /// This decreases ILP at the architecture level. Targets with ample registers, | |||
2720 | /// multiple memory ports, and no register renaming probably don't want | |||
2721 | /// this. However, such targets should probably disable LSR altogether. | |||
2722 | /// | |||
2723 | /// The job of LSR is to make a reasonable choice of induction variables across | |||
2724 | /// the loop. Subsequent passes can easily "unchain" computation exposing more | |||
2725 | /// ILP *within the loop* if the target wants it. | |||
2726 | /// | |||
2727 | /// Finding the best IV chain is potentially a scheduling problem. Since LSR | |||
2728 | /// will not reorder memory operations, it will recognize this as a chain, but | |||
2729 | /// will generate redundant IV increments. Ideally this would be corrected later | |||
2730 | /// by a smart scheduler: | |||
2731 | /// = A[i] | |||
2732 | /// = A[i+x] | |||
2733 | /// A[i] = | |||
2734 | /// A[i+x] = | |||
2735 | /// | |||
2736 | /// TODO: Walk the entire domtree within this loop, not just the path to the | |||
2737 | /// loop latch. This will discover chains on side paths, but requires | |||
2738 | /// maintaining multiple copies of the Chains state. | |||
2739 | void LSRInstance::CollectChains() { | |||
2740 | DEBUG(dbgs() << "Collecting IV Chains.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Collecting IV Chains.\n"; } } while (0); | |||
2741 | SmallVector<ChainUsers, 8> ChainUsersVec; | |||
2742 | ||||
2743 | SmallVector<BasicBlock *,8> LatchPath; | |||
2744 | BasicBlock *LoopHeader = L->getHeader(); | |||
2745 | for (DomTreeNode *Rung = DT.getNode(L->getLoopLatch()); | |||
2746 | Rung->getBlock() != LoopHeader; Rung = Rung->getIDom()) { | |||
2747 | LatchPath.push_back(Rung->getBlock()); | |||
2748 | } | |||
2749 | LatchPath.push_back(LoopHeader); | |||
2750 | ||||
2751 | // Walk the instruction stream from the loop header to the loop latch. | |||
2752 | for (SmallVectorImpl<BasicBlock *>::reverse_iterator | |||
2753 | BBIter = LatchPath.rbegin(), BBEnd = LatchPath.rend(); | |||
2754 | BBIter != BBEnd; ++BBIter) { | |||
2755 | for (BasicBlock::iterator I = (*BBIter)->begin(), E = (*BBIter)->end(); | |||
2756 | I != E; ++I) { | |||
2757 | // Skip instructions that weren't seen by IVUsers analysis. | |||
2758 | if (isa<PHINode>(I) || !IU.isIVUserOrOperand(I)) | |||
2759 | continue; | |||
2760 | ||||
2761 | // Ignore users that are part of a SCEV expression. This way we only | |||
2762 | // consider leaf IV Users. This effectively rediscovers a portion of | |||
2763 | // IVUsers analysis but in program order this time. | |||
2764 | if (SE.isSCEVable(I->getType()) && !isa<SCEVUnknown>(SE.getSCEV(I))) | |||
2765 | continue; | |||
2766 | ||||
2767 | // Remove this instruction from any NearUsers set it may be in. | |||
2768 | for (unsigned ChainIdx = 0, NChains = IVChainVec.size(); | |||
2769 | ChainIdx < NChains; ++ChainIdx) { | |||
2770 | ChainUsersVec[ChainIdx].NearUsers.erase(I); | |||
2771 | } | |||
2772 | // Search for operands that can be chained. | |||
2773 | SmallPtrSet<Instruction*, 4> UniqueOperands; | |||
2774 | User::op_iterator IVOpEnd = I->op_end(); | |||
2775 | User::op_iterator IVOpIter = findIVOperand(I->op_begin(), IVOpEnd, L, SE); | |||
2776 | while (IVOpIter != IVOpEnd) { | |||
2777 | Instruction *IVOpInst = cast<Instruction>(*IVOpIter); | |||
2778 | if (UniqueOperands.insert(IVOpInst).second) | |||
2779 | ChainInstruction(I, IVOpInst, ChainUsersVec); | |||
2780 | IVOpIter = findIVOperand(std::next(IVOpIter), IVOpEnd, L, SE); | |||
2781 | } | |||
2782 | } // Continue walking down the instructions. | |||
2783 | } // Continue walking down the domtree. | |||
2784 | // Visit phi backedges to determine if the chain can generate the IV postinc. | |||
2785 | for (BasicBlock::iterator I = L->getHeader()->begin(); | |||
2786 | PHINode *PN = dyn_cast<PHINode>(I); ++I) { | |||
2787 | if (!SE.isSCEVable(PN->getType())) | |||
2788 | continue; | |||
2789 | ||||
2790 | Instruction *IncV = | |||
2791 | dyn_cast<Instruction>(PN->getIncomingValueForBlock(L->getLoopLatch())); | |||
2792 | if (IncV) | |||
2793 | ChainInstruction(PN, IncV, ChainUsersVec); | |||
2794 | } | |||
2795 | // Remove any unprofitable chains. | |||
2796 | unsigned ChainIdx = 0; | |||
2797 | for (unsigned UsersIdx = 0, NChains = IVChainVec.size(); | |||
2798 | UsersIdx < NChains; ++UsersIdx) { | |||
2799 | if (!isProfitableChain(IVChainVec[UsersIdx], | |||
2800 | ChainUsersVec[UsersIdx].FarUsers, SE, TTI)) | |||
2801 | continue; | |||
2802 | // Preserve the chain at UsesIdx. | |||
2803 | if (ChainIdx != UsersIdx) | |||
2804 | IVChainVec[ChainIdx] = IVChainVec[UsersIdx]; | |||
2805 | FinalizeChain(IVChainVec[ChainIdx]); | |||
2806 | ++ChainIdx; | |||
2807 | } | |||
2808 | IVChainVec.resize(ChainIdx); | |||
2809 | } | |||
2810 | ||||
2811 | void LSRInstance::FinalizeChain(IVChain &Chain) { | |||
2812 | assert(!Chain.Incs.empty() && "empty IV chains are not allowed")((!Chain.Incs.empty() && "empty IV chains are not allowed" ) ? static_cast<void> (0) : __assert_fail ("!Chain.Incs.empty() && \"empty IV chains are not allowed\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2812, __PRETTY_FUNCTION__)); | |||
2813 | DEBUG(dbgs() << "Final Chain: " << *Chain.Incs[0].UserInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Final Chain: " << * Chain.Incs[0].UserInst << "\n"; } } while (0); | |||
2814 | ||||
2815 | for (const IVInc &Inc : Chain) { | |||
2816 | DEBUG(dbgs() << " Inc: " << Inc.UserInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Inc: " << Inc .UserInst << "\n"; } } while (0); | |||
2817 | auto UseI = std::find(Inc.UserInst->op_begin(), Inc.UserInst->op_end(), | |||
2818 | Inc.IVOperand); | |||
2819 | assert(UseI != Inc.UserInst->op_end() && "cannot find IV operand")((UseI != Inc.UserInst->op_end() && "cannot find IV operand" ) ? static_cast<void> (0) : __assert_fail ("UseI != Inc.UserInst->op_end() && \"cannot find IV operand\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2819, __PRETTY_FUNCTION__)); | |||
2820 | IVIncSet.insert(UseI); | |||
2821 | } | |||
2822 | } | |||
2823 | ||||
2824 | /// Return true if the IVInc can be folded into an addressing mode. | |||
2825 | static bool canFoldIVIncExpr(const SCEV *IncExpr, Instruction *UserInst, | |||
2826 | Value *Operand, const TargetTransformInfo &TTI) { | |||
2827 | const SCEVConstant *IncConst = dyn_cast<SCEVConstant>(IncExpr); | |||
2828 | if (!IncConst || !isAddressUse(UserInst, Operand)) | |||
2829 | return false; | |||
2830 | ||||
2831 | if (IncConst->getValue()->getValue().getMinSignedBits() > 64) | |||
2832 | return false; | |||
2833 | ||||
2834 | int64_t IncOffset = IncConst->getValue()->getSExtValue(); | |||
2835 | if (!isAlwaysFoldable(TTI, LSRUse::Address, | |||
2836 | getAccessType(UserInst), /*BaseGV=*/ nullptr, | |||
2837 | IncOffset, /*HaseBaseReg=*/ false)) | |||
2838 | return false; | |||
2839 | ||||
2840 | return true; | |||
2841 | } | |||
2842 | ||||
2843 | /// GenerateIVChains - Generate an add or subtract for each IVInc in a chain to | |||
2844 | /// materialize the IV user's operand from the previous IV user's operand. | |||
2845 | void LSRInstance::GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter, | |||
2846 | SmallVectorImpl<WeakVH> &DeadInsts) { | |||
2847 | // Find the new IVOperand for the head of the chain. It may have been replaced | |||
2848 | // by LSR. | |||
2849 | const IVInc &Head = Chain.Incs[0]; | |||
2850 | User::op_iterator IVOpEnd = Head.UserInst->op_end(); | |||
2851 | // findIVOperand returns IVOpEnd if it can no longer find a valid IV user. | |||
2852 | User::op_iterator IVOpIter = findIVOperand(Head.UserInst->op_begin(), | |||
2853 | IVOpEnd, L, SE); | |||
2854 | Value *IVSrc = nullptr; | |||
2855 | while (IVOpIter != IVOpEnd) { | |||
2856 | IVSrc = getWideOperand(*IVOpIter); | |||
2857 | ||||
2858 | // If this operand computes the expression that the chain needs, we may use | |||
2859 | // it. (Check this after setting IVSrc which is used below.) | |||
2860 | // | |||
2861 | // Note that if Head.IncExpr is wider than IVSrc, then this phi is too | |||
2862 | // narrow for the chain, so we can no longer use it. We do allow using a | |||
2863 | // wider phi, assuming the LSR checked for free truncation. In that case we | |||
2864 | // should already have a truncate on this operand such that | |||
2865 | // getSCEV(IVSrc) == IncExpr. | |||
2866 | if (SE.getSCEV(*IVOpIter) == Head.IncExpr | |||
2867 | || SE.getSCEV(IVSrc) == Head.IncExpr) { | |||
2868 | break; | |||
2869 | } | |||
2870 | IVOpIter = findIVOperand(std::next(IVOpIter), IVOpEnd, L, SE); | |||
2871 | } | |||
2872 | if (IVOpIter == IVOpEnd) { | |||
2873 | // Gracefully give up on this chain. | |||
2874 | DEBUG(dbgs() << "Concealed chain head: " << *Head.UserInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Concealed chain head: " << *Head.UserInst << "\n"; } } while (0); | |||
2875 | return; | |||
2876 | } | |||
2877 | ||||
2878 | DEBUG(dbgs() << "Generate chain at: " << *IVSrc << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Generate chain at: " << *IVSrc << "\n"; } } while (0); | |||
2879 | Type *IVTy = IVSrc->getType(); | |||
2880 | Type *IntTy = SE.getEffectiveSCEVType(IVTy); | |||
2881 | const SCEV *LeftOverExpr = nullptr; | |||
2882 | for (const IVInc &Inc : Chain) { | |||
2883 | Instruction *InsertPt = Inc.UserInst; | |||
2884 | if (isa<PHINode>(InsertPt)) | |||
2885 | InsertPt = L->getLoopLatch()->getTerminator(); | |||
2886 | ||||
2887 | // IVOper will replace the current IV User's operand. IVSrc is the IV | |||
2888 | // value currently held in a register. | |||
2889 | Value *IVOper = IVSrc; | |||
2890 | if (!Inc.IncExpr->isZero()) { | |||
2891 | // IncExpr was the result of subtraction of two narrow values, so must | |||
2892 | // be signed. | |||
2893 | const SCEV *IncExpr = SE.getNoopOrSignExtend(Inc.IncExpr, IntTy); | |||
2894 | LeftOverExpr = LeftOverExpr ? | |||
2895 | SE.getAddExpr(LeftOverExpr, IncExpr) : IncExpr; | |||
2896 | } | |||
2897 | if (LeftOverExpr && !LeftOverExpr->isZero()) { | |||
2898 | // Expand the IV increment. | |||
2899 | Rewriter.clearPostInc(); | |||
2900 | Value *IncV = Rewriter.expandCodeFor(LeftOverExpr, IntTy, InsertPt); | |||
2901 | const SCEV *IVOperExpr = SE.getAddExpr(SE.getUnknown(IVSrc), | |||
2902 | SE.getUnknown(IncV)); | |||
2903 | IVOper = Rewriter.expandCodeFor(IVOperExpr, IVTy, InsertPt); | |||
2904 | ||||
2905 | // If an IV increment can't be folded, use it as the next IV value. | |||
2906 | if (!canFoldIVIncExpr(LeftOverExpr, Inc.UserInst, Inc.IVOperand, TTI)) { | |||
2907 | assert(IVTy == IVOper->getType() && "inconsistent IV increment type")((IVTy == IVOper->getType() && "inconsistent IV increment type" ) ? static_cast<void> (0) : __assert_fail ("IVTy == IVOper->getType() && \"inconsistent IV increment type\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2907, __PRETTY_FUNCTION__)); | |||
2908 | IVSrc = IVOper; | |||
2909 | LeftOverExpr = nullptr; | |||
2910 | } | |||
2911 | } | |||
2912 | Type *OperTy = Inc.IVOperand->getType(); | |||
2913 | if (IVTy != OperTy) { | |||
2914 | assert(SE.getTypeSizeInBits(IVTy) >= SE.getTypeSizeInBits(OperTy) &&((SE.getTypeSizeInBits(IVTy) >= SE.getTypeSizeInBits(OperTy ) && "cannot extend a chained IV") ? static_cast<void > (0) : __assert_fail ("SE.getTypeSizeInBits(IVTy) >= SE.getTypeSizeInBits(OperTy) && \"cannot extend a chained IV\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2915, __PRETTY_FUNCTION__)) | |||
2915 | "cannot extend a chained IV")((SE.getTypeSizeInBits(IVTy) >= SE.getTypeSizeInBits(OperTy ) && "cannot extend a chained IV") ? static_cast<void > (0) : __assert_fail ("SE.getTypeSizeInBits(IVTy) >= SE.getTypeSizeInBits(OperTy) && \"cannot extend a chained IV\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2915, __PRETTY_FUNCTION__)); | |||
2916 | IRBuilder<> Builder(InsertPt); | |||
2917 | IVOper = Builder.CreateTruncOrBitCast(IVOper, OperTy, "lsr.chain"); | |||
2918 | } | |||
2919 | Inc.UserInst->replaceUsesOfWith(Inc.IVOperand, IVOper); | |||
2920 | DeadInsts.emplace_back(Inc.IVOperand); | |||
2921 | } | |||
2922 | // If LSR created a new, wider phi, we may also replace its postinc. We only | |||
2923 | // do this if we also found a wide value for the head of the chain. | |||
2924 | if (isa<PHINode>(Chain.tailUserInst())) { | |||
2925 | for (BasicBlock::iterator I = L->getHeader()->begin(); | |||
2926 | PHINode *Phi = dyn_cast<PHINode>(I); ++I) { | |||
2927 | if (!isCompatibleIVType(Phi, IVSrc)) | |||
2928 | continue; | |||
2929 | Instruction *PostIncV = dyn_cast<Instruction>( | |||
2930 | Phi->getIncomingValueForBlock(L->getLoopLatch())); | |||
2931 | if (!PostIncV || (SE.getSCEV(PostIncV) != SE.getSCEV(IVSrc))) | |||
2932 | continue; | |||
2933 | Value *IVOper = IVSrc; | |||
2934 | Type *PostIncTy = PostIncV->getType(); | |||
2935 | if (IVTy != PostIncTy) { | |||
2936 | assert(PostIncTy->isPointerTy() && "mixing int/ptr IV types")((PostIncTy->isPointerTy() && "mixing int/ptr IV types" ) ? static_cast<void> (0) : __assert_fail ("PostIncTy->isPointerTy() && \"mixing int/ptr IV types\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2936, __PRETTY_FUNCTION__)); | |||
2937 | IRBuilder<> Builder(L->getLoopLatch()->getTerminator()); | |||
2938 | Builder.SetCurrentDebugLocation(PostIncV->getDebugLoc()); | |||
2939 | IVOper = Builder.CreatePointerCast(IVSrc, PostIncTy, "lsr.chain"); | |||
2940 | } | |||
2941 | Phi->replaceUsesOfWith(PostIncV, IVOper); | |||
2942 | DeadInsts.emplace_back(PostIncV); | |||
2943 | } | |||
2944 | } | |||
2945 | } | |||
2946 | ||||
2947 | void LSRInstance::CollectFixupsAndInitialFormulae() { | |||
2948 | for (const IVStrideUse &U : IU) { | |||
2949 | Instruction *UserInst = U.getUser(); | |||
2950 | // Skip IV users that are part of profitable IV Chains. | |||
2951 | User::op_iterator UseI = std::find(UserInst->op_begin(), UserInst->op_end(), | |||
2952 | U.getOperandValToReplace()); | |||
2953 | assert(UseI != UserInst->op_end() && "cannot find IV operand")((UseI != UserInst->op_end() && "cannot find IV operand" ) ? static_cast<void> (0) : __assert_fail ("UseI != UserInst->op_end() && \"cannot find IV operand\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 2953, __PRETTY_FUNCTION__)); | |||
2954 | if (IVIncSet.count(UseI)) | |||
2955 | continue; | |||
2956 | ||||
2957 | // Record the uses. | |||
2958 | LSRFixup &LF = getNewFixup(); | |||
2959 | LF.UserInst = UserInst; | |||
2960 | LF.OperandValToReplace = U.getOperandValToReplace(); | |||
2961 | LF.PostIncLoops = U.getPostIncLoops(); | |||
2962 | ||||
2963 | LSRUse::KindType Kind = LSRUse::Basic; | |||
2964 | Type *AccessTy = nullptr; | |||
2965 | if (isAddressUse(LF.UserInst, LF.OperandValToReplace)) { | |||
2966 | Kind = LSRUse::Address; | |||
2967 | AccessTy = getAccessType(LF.UserInst); | |||
2968 | } | |||
2969 | ||||
2970 | const SCEV *S = IU.getExpr(U); | |||
2971 | ||||
2972 | // Equality (== and !=) ICmps are special. We can rewrite (i == N) as | |||
2973 | // (N - i == 0), and this allows (N - i) to be the expression that we work | |||
2974 | // with rather than just N or i, so we can consider the register | |||
2975 | // requirements for both N and i at the same time. Limiting this code to | |||
2976 | // equality icmps is not a problem because all interesting loops use | |||
2977 | // equality icmps, thanks to IndVarSimplify. | |||
2978 | if (ICmpInst *CI = dyn_cast<ICmpInst>(LF.UserInst)) | |||
2979 | if (CI->isEquality()) { | |||
2980 | // Swap the operands if needed to put the OperandValToReplace on the | |||
2981 | // left, for consistency. | |||
2982 | Value *NV = CI->getOperand(1); | |||
2983 | if (NV == LF.OperandValToReplace) { | |||
2984 | CI->setOperand(1, CI->getOperand(0)); | |||
2985 | CI->setOperand(0, NV); | |||
2986 | NV = CI->getOperand(1); | |||
2987 | Changed = true; | |||
2988 | } | |||
2989 | ||||
2990 | // x == y --> x - y == 0 | |||
2991 | const SCEV *N = SE.getSCEV(NV); | |||
2992 | if (SE.isLoopInvariant(N, L) && isSafeToExpand(N, SE)) { | |||
2993 | // S is normalized, so normalize N before folding it into S | |||
2994 | // to keep the result normalized. | |||
2995 | N = TransformForPostIncUse(Normalize, N, CI, nullptr, | |||
2996 | LF.PostIncLoops, SE, DT); | |||
2997 | Kind = LSRUse::ICmpZero; | |||
2998 | S = SE.getMinusSCEV(N, S); | |||
2999 | } | |||
3000 | ||||
3001 | // -1 and the negations of all interesting strides (except the negation | |||
3002 | // of -1) are now also interesting. | |||
3003 | for (size_t i = 0, e = Factors.size(); i != e; ++i) | |||
3004 | if (Factors[i] != -1) | |||
3005 | Factors.insert(-(uint64_t)Factors[i]); | |||
3006 | Factors.insert(-1); | |||
3007 | } | |||
3008 | ||||
3009 | // Set up the initial formula for this use. | |||
3010 | std::pair<size_t, int64_t> P = getUse(S, Kind, AccessTy); | |||
3011 | LF.LUIdx = P.first; | |||
3012 | LF.Offset = P.second; | |||
3013 | LSRUse &LU = Uses[LF.LUIdx]; | |||
3014 | LU.AllFixupsOutsideLoop &= LF.isUseFullyOutsideLoop(L); | |||
3015 | if (!LU.WidestFixupType || | |||
3016 | SE.getTypeSizeInBits(LU.WidestFixupType) < | |||
3017 | SE.getTypeSizeInBits(LF.OperandValToReplace->getType())) | |||
3018 | LU.WidestFixupType = LF.OperandValToReplace->getType(); | |||
3019 | ||||
3020 | // If this is the first use of this LSRUse, give it a formula. | |||
3021 | if (LU.Formulae.empty()) { | |||
3022 | InsertInitialFormula(S, LU, LF.LUIdx); | |||
3023 | CountRegisters(LU.Formulae.back(), LF.LUIdx); | |||
3024 | } | |||
3025 | } | |||
3026 | ||||
3027 | DEBUG(print_fixups(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { print_fixups(dbgs()); } } while (0); | |||
3028 | } | |||
3029 | ||||
3030 | /// InsertInitialFormula - Insert a formula for the given expression into | |||
3031 | /// the given use, separating out loop-variant portions from loop-invariant | |||
3032 | /// and loop-computable portions. | |||
3033 | void | |||
3034 | LSRInstance::InsertInitialFormula(const SCEV *S, LSRUse &LU, size_t LUIdx) { | |||
3035 | // Mark uses whose expressions cannot be expanded. | |||
3036 | if (!isSafeToExpand(S, SE)) | |||
3037 | LU.RigidFormula = true; | |||
3038 | ||||
3039 | Formula F; | |||
3040 | F.InitialMatch(S, L, SE); | |||
3041 | bool Inserted = InsertFormula(LU, LUIdx, F); | |||
3042 | assert(Inserted && "Initial formula already exists!")((Inserted && "Initial formula already exists!") ? static_cast <void> (0) : __assert_fail ("Inserted && \"Initial formula already exists!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 3042, __PRETTY_FUNCTION__)); (void)Inserted; | |||
3043 | } | |||
3044 | ||||
3045 | /// InsertSupplementalFormula - Insert a simple single-register formula for | |||
3046 | /// the given expression into the given use. | |||
3047 | void | |||
3048 | LSRInstance::InsertSupplementalFormula(const SCEV *S, | |||
3049 | LSRUse &LU, size_t LUIdx) { | |||
3050 | Formula F; | |||
3051 | F.BaseRegs.push_back(S); | |||
3052 | F.HasBaseReg = true; | |||
3053 | bool Inserted = InsertFormula(LU, LUIdx, F); | |||
3054 | assert(Inserted && "Supplemental formula already exists!")((Inserted && "Supplemental formula already exists!") ? static_cast<void> (0) : __assert_fail ("Inserted && \"Supplemental formula already exists!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 3054, __PRETTY_FUNCTION__)); (void)Inserted; | |||
3055 | } | |||
3056 | ||||
3057 | /// CountRegisters - Note which registers are used by the given formula, | |||
3058 | /// updating RegUses. | |||
3059 | void LSRInstance::CountRegisters(const Formula &F, size_t LUIdx) { | |||
3060 | if (F.ScaledReg) | |||
3061 | RegUses.CountRegister(F.ScaledReg, LUIdx); | |||
3062 | for (const SCEV *BaseReg : F.BaseRegs) | |||
3063 | RegUses.CountRegister(BaseReg, LUIdx); | |||
3064 | } | |||
3065 | ||||
3066 | /// InsertFormula - If the given formula has not yet been inserted, add it to | |||
3067 | /// the list, and return true. Return false otherwise. | |||
3068 | bool LSRInstance::InsertFormula(LSRUse &LU, unsigned LUIdx, const Formula &F) { | |||
3069 | // Do not insert formula that we will not be able to expand. | |||
3070 | assert(isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, F) &&((isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy , F) && "Formula is illegal") ? static_cast<void> (0) : __assert_fail ("isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, F) && \"Formula is illegal\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 3071, __PRETTY_FUNCTION__)) | |||
3071 | "Formula is illegal")((isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy , F) && "Formula is illegal") ? static_cast<void> (0) : __assert_fail ("isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, F) && \"Formula is illegal\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 3071, __PRETTY_FUNCTION__)); | |||
3072 | if (!LU.InsertFormula(F)) | |||
3073 | return false; | |||
3074 | ||||
3075 | CountRegisters(F, LUIdx); | |||
3076 | return true; | |||
3077 | } | |||
3078 | ||||
3079 | /// CollectLoopInvariantFixupsAndFormulae - Check for other uses of | |||
3080 | /// loop-invariant values which we're tracking. These other uses will pin these | |||
3081 | /// values in registers, making them less profitable for elimination. | |||
3082 | /// TODO: This currently misses non-constant addrec step registers. | |||
3083 | /// TODO: Should this give more weight to users inside the loop? | |||
3084 | void | |||
3085 | LSRInstance::CollectLoopInvariantFixupsAndFormulae() { | |||
3086 | SmallVector<const SCEV *, 8> Worklist(RegUses.begin(), RegUses.end()); | |||
3087 | SmallPtrSet<const SCEV *, 32> Visited; | |||
3088 | ||||
3089 | while (!Worklist.empty()) { | |||
3090 | const SCEV *S = Worklist.pop_back_val(); | |||
3091 | ||||
3092 | // Don't process the same SCEV twice | |||
3093 | if (!Visited.insert(S).second) | |||
3094 | continue; | |||
3095 | ||||
3096 | if (const SCEVNAryExpr *N = dyn_cast<SCEVNAryExpr>(S)) | |||
3097 | Worklist.append(N->op_begin(), N->op_end()); | |||
3098 | else if (const SCEVCastExpr *C = dyn_cast<SCEVCastExpr>(S)) | |||
3099 | Worklist.push_back(C->getOperand()); | |||
3100 | else if (const SCEVUDivExpr *D = dyn_cast<SCEVUDivExpr>(S)) { | |||
3101 | Worklist.push_back(D->getLHS()); | |||
3102 | Worklist.push_back(D->getRHS()); | |||
3103 | } else if (const SCEVUnknown *US = dyn_cast<SCEVUnknown>(S)) { | |||
3104 | const Value *V = US->getValue(); | |||
3105 | if (const Instruction *Inst = dyn_cast<Instruction>(V)) { | |||
3106 | // Look for instructions defined outside the loop. | |||
3107 | if (L->contains(Inst)) continue; | |||
3108 | } else if (isa<UndefValue>(V)) | |||
3109 | // Undef doesn't have a live range, so it doesn't matter. | |||
3110 | continue; | |||
3111 | for (const Use &U : V->uses()) { | |||
3112 | const Instruction *UserInst = dyn_cast<Instruction>(U.getUser()); | |||
3113 | // Ignore non-instructions. | |||
3114 | if (!UserInst) | |||
3115 | continue; | |||
3116 | // Ignore instructions in other functions (as can happen with | |||
3117 | // Constants). | |||
3118 | if (UserInst->getParent()->getParent() != L->getHeader()->getParent()) | |||
3119 | continue; | |||
3120 | // Ignore instructions not dominated by the loop. | |||
3121 | const BasicBlock *UseBB = !isa<PHINode>(UserInst) ? | |||
3122 | UserInst->getParent() : | |||
3123 | cast<PHINode>(UserInst)->getIncomingBlock( | |||
3124 | PHINode::getIncomingValueNumForOperand(U.getOperandNo())); | |||
3125 | if (!DT.dominates(L->getHeader(), UseBB)) | |||
3126 | continue; | |||
3127 | // Ignore uses which are part of other SCEV expressions, to avoid | |||
3128 | // analyzing them multiple times. | |||
3129 | if (SE.isSCEVable(UserInst->getType())) { | |||
3130 | const SCEV *UserS = SE.getSCEV(const_cast<Instruction *>(UserInst)); | |||
3131 | // If the user is a no-op, look through to its uses. | |||
3132 | if (!isa<SCEVUnknown>(UserS)) | |||
3133 | continue; | |||
3134 | if (UserS == US) { | |||
3135 | Worklist.push_back( | |||
3136 | SE.getUnknown(const_cast<Instruction *>(UserInst))); | |||
3137 | continue; | |||
3138 | } | |||
3139 | } | |||
3140 | // Ignore icmp instructions which are already being analyzed. | |||
3141 | if (const ICmpInst *ICI = dyn_cast<ICmpInst>(UserInst)) { | |||
3142 | unsigned OtherIdx = !U.getOperandNo(); | |||
3143 | Value *OtherOp = const_cast<Value *>(ICI->getOperand(OtherIdx)); | |||
3144 | if (SE.hasComputableLoopEvolution(SE.getSCEV(OtherOp), L)) | |||
3145 | continue; | |||
3146 | } | |||
3147 | ||||
3148 | LSRFixup &LF = getNewFixup(); | |||
3149 | LF.UserInst = const_cast<Instruction *>(UserInst); | |||
3150 | LF.OperandValToReplace = U; | |||
3151 | std::pair<size_t, int64_t> P = getUse(S, LSRUse::Basic, nullptr); | |||
3152 | LF.LUIdx = P.first; | |||
3153 | LF.Offset = P.second; | |||
3154 | LSRUse &LU = Uses[LF.LUIdx]; | |||
3155 | LU.AllFixupsOutsideLoop &= LF.isUseFullyOutsideLoop(L); | |||
3156 | if (!LU.WidestFixupType || | |||
3157 | SE.getTypeSizeInBits(LU.WidestFixupType) < | |||
3158 | SE.getTypeSizeInBits(LF.OperandValToReplace->getType())) | |||
3159 | LU.WidestFixupType = LF.OperandValToReplace->getType(); | |||
3160 | InsertSupplementalFormula(US, LU, LF.LUIdx); | |||
3161 | CountRegisters(LU.Formulae.back(), Uses.size() - 1); | |||
3162 | break; | |||
3163 | } | |||
3164 | } | |||
3165 | } | |||
3166 | } | |||
3167 | ||||
3168 | /// CollectSubexprs - Split S into subexpressions which can be pulled out into | |||
3169 | /// separate registers. If C is non-null, multiply each subexpression by C. | |||
3170 | /// | |||
3171 | /// Return remainder expression after factoring the subexpressions captured by | |||
3172 | /// Ops. If Ops is complete, return NULL. | |||
3173 | static const SCEV *CollectSubexprs(const SCEV *S, const SCEVConstant *C, | |||
3174 | SmallVectorImpl<const SCEV *> &Ops, | |||
3175 | const Loop *L, | |||
3176 | ScalarEvolution &SE, | |||
3177 | unsigned Depth = 0) { | |||
3178 | // Arbitrarily cap recursion to protect compile time. | |||
3179 | if (Depth >= 3) | |||
3180 | return S; | |||
3181 | ||||
3182 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | |||
3183 | // Break out add operands. | |||
3184 | for (const SCEV *S : Add->operands()) { | |||
3185 | const SCEV *Remainder = CollectSubexprs(S, C, Ops, L, SE, Depth+1); | |||
3186 | if (Remainder) | |||
3187 | Ops.push_back(C ? SE.getMulExpr(C, Remainder) : Remainder); | |||
3188 | } | |||
3189 | return nullptr; | |||
3190 | } else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) { | |||
3191 | // Split a non-zero base out of an addrec. | |||
3192 | if (AR->getStart()->isZero()) | |||
3193 | return S; | |||
3194 | ||||
3195 | const SCEV *Remainder = CollectSubexprs(AR->getStart(), | |||
3196 | C, Ops, L, SE, Depth+1); | |||
3197 | // Split the non-zero AddRec unless it is part of a nested recurrence that | |||
3198 | // does not pertain to this loop. | |||
3199 | if (Remainder && (AR->getLoop() == L || !isa<SCEVAddRecExpr>(Remainder))) { | |||
3200 | Ops.push_back(C ? SE.getMulExpr(C, Remainder) : Remainder); | |||
3201 | Remainder = nullptr; | |||
3202 | } | |||
3203 | if (Remainder != AR->getStart()) { | |||
3204 | if (!Remainder) | |||
3205 | Remainder = SE.getConstant(AR->getType(), 0); | |||
3206 | return SE.getAddRecExpr(Remainder, | |||
3207 | AR->getStepRecurrence(SE), | |||
3208 | AR->getLoop(), | |||
3209 | //FIXME: AR->getNoWrapFlags(SCEV::FlagNW) | |||
3210 | SCEV::FlagAnyWrap); | |||
3211 | } | |||
3212 | } else if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) { | |||
3213 | // Break (C * (a + b + c)) into C*a + C*b + C*c. | |||
3214 | if (Mul->getNumOperands() != 2) | |||
3215 | return S; | |||
3216 | if (const SCEVConstant *Op0 = | |||
3217 | dyn_cast<SCEVConstant>(Mul->getOperand(0))) { | |||
3218 | C = C ? cast<SCEVConstant>(SE.getMulExpr(C, Op0)) : Op0; | |||
3219 | const SCEV *Remainder = | |||
3220 | CollectSubexprs(Mul->getOperand(1), C, Ops, L, SE, Depth+1); | |||
3221 | if (Remainder) | |||
3222 | Ops.push_back(SE.getMulExpr(C, Remainder)); | |||
3223 | return nullptr; | |||
3224 | } | |||
3225 | } | |||
3226 | return S; | |||
3227 | } | |||
3228 | ||||
3229 | /// \brief Helper function for LSRInstance::GenerateReassociations. | |||
3230 | void LSRInstance::GenerateReassociationsImpl(LSRUse &LU, unsigned LUIdx, | |||
3231 | const Formula &Base, | |||
3232 | unsigned Depth, size_t Idx, | |||
3233 | bool IsScaledReg) { | |||
3234 | const SCEV *BaseReg = IsScaledReg ? Base.ScaledReg : Base.BaseRegs[Idx]; | |||
3235 | SmallVector<const SCEV *, 8> AddOps; | |||
3236 | const SCEV *Remainder = CollectSubexprs(BaseReg, nullptr, AddOps, L, SE); | |||
3237 | if (Remainder) | |||
3238 | AddOps.push_back(Remainder); | |||
3239 | ||||
3240 | if (AddOps.size() == 1) | |||
3241 | return; | |||
3242 | ||||
3243 | for (SmallVectorImpl<const SCEV *>::const_iterator J = AddOps.begin(), | |||
3244 | JE = AddOps.end(); | |||
3245 | J != JE; ++J) { | |||
3246 | ||||
3247 | // Loop-variant "unknown" values are uninteresting; we won't be able to | |||
3248 | // do anything meaningful with them. | |||
3249 | if (isa<SCEVUnknown>(*J) && !SE.isLoopInvariant(*J, L)) | |||
3250 | continue; | |||
3251 | ||||
3252 | // Don't pull a constant into a register if the constant could be folded | |||
3253 | // into an immediate field. | |||
3254 | if (isAlwaysFoldable(TTI, SE, LU.MinOffset, LU.MaxOffset, LU.Kind, | |||
3255 | LU.AccessTy, *J, Base.getNumRegs() > 1)) | |||
3256 | continue; | |||
3257 | ||||
3258 | // Collect all operands except *J. | |||
3259 | SmallVector<const SCEV *, 8> InnerAddOps( | |||
3260 | ((const SmallVector<const SCEV *, 8> &)AddOps).begin(), J); | |||
3261 | InnerAddOps.append(std::next(J), | |||
3262 | ((const SmallVector<const SCEV *, 8> &)AddOps).end()); | |||
3263 | ||||
3264 | // Don't leave just a constant behind in a register if the constant could | |||
3265 | // be folded into an immediate field. | |||
3266 | if (InnerAddOps.size() == 1 && | |||
3267 | isAlwaysFoldable(TTI, SE, LU.MinOffset, LU.MaxOffset, LU.Kind, | |||
3268 | LU.AccessTy, InnerAddOps[0], Base.getNumRegs() > 1)) | |||
3269 | continue; | |||
3270 | ||||
3271 | const SCEV *InnerSum = SE.getAddExpr(InnerAddOps); | |||
3272 | if (InnerSum->isZero()) | |||
3273 | continue; | |||
3274 | Formula F = Base; | |||
3275 | ||||
3276 | // Add the remaining pieces of the add back into the new formula. | |||
3277 | const SCEVConstant *InnerSumSC = dyn_cast<SCEVConstant>(InnerSum); | |||
3278 | if (InnerSumSC && SE.getTypeSizeInBits(InnerSumSC->getType()) <= 64 && | |||
3279 | TTI.isLegalAddImmediate((uint64_t)F.UnfoldedOffset + | |||
3280 | InnerSumSC->getValue()->getZExtValue())) { | |||
3281 | F.UnfoldedOffset = | |||
3282 | (uint64_t)F.UnfoldedOffset + InnerSumSC->getValue()->getZExtValue(); | |||
3283 | if (IsScaledReg) | |||
3284 | F.ScaledReg = nullptr; | |||
3285 | else | |||
3286 | F.BaseRegs.erase(F.BaseRegs.begin() + Idx); | |||
3287 | } else if (IsScaledReg) | |||
3288 | F.ScaledReg = InnerSum; | |||
3289 | else | |||
3290 | F.BaseRegs[Idx] = InnerSum; | |||
3291 | ||||
3292 | // Add J as its own register, or an unfolded immediate. | |||
3293 | const SCEVConstant *SC = dyn_cast<SCEVConstant>(*J); | |||
3294 | if (SC && SE.getTypeSizeInBits(SC->getType()) <= 64 && | |||
3295 | TTI.isLegalAddImmediate((uint64_t)F.UnfoldedOffset + | |||
3296 | SC->getValue()->getZExtValue())) | |||
3297 | F.UnfoldedOffset = | |||
3298 | (uint64_t)F.UnfoldedOffset + SC->getValue()->getZExtValue(); | |||
3299 | else | |||
3300 | F.BaseRegs.push_back(*J); | |||
3301 | // We may have changed the number of register in base regs, adjust the | |||
3302 | // formula accordingly. | |||
3303 | F.Canonicalize(); | |||
3304 | ||||
3305 | if (InsertFormula(LU, LUIdx, F)) | |||
3306 | // If that formula hadn't been seen before, recurse to find more like | |||
3307 | // it. | |||
3308 | GenerateReassociations(LU, LUIdx, LU.Formulae.back(), Depth + 1); | |||
3309 | } | |||
3310 | } | |||
3311 | ||||
3312 | /// GenerateReassociations - Split out subexpressions from adds and the bases of | |||
3313 | /// addrecs. | |||
3314 | void LSRInstance::GenerateReassociations(LSRUse &LU, unsigned LUIdx, | |||
3315 | Formula Base, unsigned Depth) { | |||
3316 | assert(Base.isCanonical() && "Input must be in the canonical form")((Base.isCanonical() && "Input must be in the canonical form" ) ? static_cast<void> (0) : __assert_fail ("Base.isCanonical() && \"Input must be in the canonical form\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 3316, __PRETTY_FUNCTION__)); | |||
3317 | // Arbitrarily cap recursion to protect compile time. | |||
3318 | if (Depth >= 3) | |||
3319 | return; | |||
3320 | ||||
3321 | for (size_t i = 0, e = Base.BaseRegs.size(); i != e; ++i) | |||
3322 | GenerateReassociationsImpl(LU, LUIdx, Base, Depth, i); | |||
3323 | ||||
3324 | if (Base.Scale == 1) | |||
3325 | GenerateReassociationsImpl(LU, LUIdx, Base, Depth, | |||
3326 | /* Idx */ -1, /* IsScaledReg */ true); | |||
3327 | } | |||
3328 | ||||
3329 | /// GenerateCombinations - Generate a formula consisting of all of the | |||
3330 | /// loop-dominating registers added into a single register. | |||
3331 | void LSRInstance::GenerateCombinations(LSRUse &LU, unsigned LUIdx, | |||
3332 | Formula Base) { | |||
3333 | // This method is only interesting on a plurality of registers. | |||
3334 | if (Base.BaseRegs.size() + (Base.Scale == 1) <= 1) | |||
3335 | return; | |||
3336 | ||||
3337 | // Flatten the representation, i.e., reg1 + 1*reg2 => reg1 + reg2, before | |||
3338 | // processing the formula. | |||
3339 | Base.Unscale(); | |||
3340 | Formula F = Base; | |||
3341 | F.BaseRegs.clear(); | |||
3342 | SmallVector<const SCEV *, 4> Ops; | |||
3343 | for (const SCEV *BaseReg : Base.BaseRegs) { | |||
3344 | if (SE.properlyDominates(BaseReg, L->getHeader()) && | |||
3345 | !SE.hasComputableLoopEvolution(BaseReg, L)) | |||
3346 | Ops.push_back(BaseReg); | |||
3347 | else | |||
3348 | F.BaseRegs.push_back(BaseReg); | |||
3349 | } | |||
3350 | if (Ops.size() > 1) { | |||
3351 | const SCEV *Sum = SE.getAddExpr(Ops); | |||
3352 | // TODO: If Sum is zero, it probably means ScalarEvolution missed an | |||
3353 | // opportunity to fold something. For now, just ignore such cases | |||
3354 | // rather than proceed with zero in a register. | |||
3355 | if (!Sum->isZero()) { | |||
3356 | F.BaseRegs.push_back(Sum); | |||
3357 | F.Canonicalize(); | |||
3358 | (void)InsertFormula(LU, LUIdx, F); | |||
3359 | } | |||
3360 | } | |||
3361 | } | |||
3362 | ||||
3363 | /// \brief Helper function for LSRInstance::GenerateSymbolicOffsets. | |||
3364 | void LSRInstance::GenerateSymbolicOffsetsImpl(LSRUse &LU, unsigned LUIdx, | |||
3365 | const Formula &Base, size_t Idx, | |||
3366 | bool IsScaledReg) { | |||
3367 | const SCEV *G = IsScaledReg ? Base.ScaledReg : Base.BaseRegs[Idx]; | |||
3368 | GlobalValue *GV = ExtractSymbol(G, SE); | |||
3369 | if (G->isZero() || !GV) | |||
3370 | return; | |||
3371 | Formula F = Base; | |||
3372 | F.BaseGV = GV; | |||
3373 | if (!isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, F)) | |||
3374 | return; | |||
3375 | if (IsScaledReg) | |||
3376 | F.ScaledReg = G; | |||
3377 | else | |||
3378 | F.BaseRegs[Idx] = G; | |||
3379 | (void)InsertFormula(LU, LUIdx, F); | |||
3380 | } | |||
3381 | ||||
3382 | /// GenerateSymbolicOffsets - Generate reuse formulae using symbolic offsets. | |||
3383 | void LSRInstance::GenerateSymbolicOffsets(LSRUse &LU, unsigned LUIdx, | |||
3384 | Formula Base) { | |||
3385 | // We can't add a symbolic offset if the address already contains one. | |||
3386 | if (Base.BaseGV) return; | |||
3387 | ||||
3388 | for (size_t i = 0, e = Base.BaseRegs.size(); i != e; ++i) | |||
3389 | GenerateSymbolicOffsetsImpl(LU, LUIdx, Base, i); | |||
3390 | if (Base.Scale == 1) | |||
3391 | GenerateSymbolicOffsetsImpl(LU, LUIdx, Base, /* Idx */ -1, | |||
3392 | /* IsScaledReg */ true); | |||
3393 | } | |||
3394 | ||||
3395 | /// \brief Helper function for LSRInstance::GenerateConstantOffsets. | |||
3396 | void LSRInstance::GenerateConstantOffsetsImpl( | |||
3397 | LSRUse &LU, unsigned LUIdx, const Formula &Base, | |||
3398 | const SmallVectorImpl<int64_t> &Worklist, size_t Idx, bool IsScaledReg) { | |||
3399 | const SCEV *G = IsScaledReg ? Base.ScaledReg : Base.BaseRegs[Idx]; | |||
3400 | for (int64_t Offset : Worklist) { | |||
3401 | Formula F = Base; | |||
3402 | F.BaseOffset = (uint64_t)Base.BaseOffset - Offset; | |||
3403 | if (isLegalUse(TTI, LU.MinOffset - Offset, LU.MaxOffset - Offset, LU.Kind, | |||
3404 | LU.AccessTy, F)) { | |||
3405 | // Add the offset to the base register. | |||
3406 | const SCEV *NewG = SE.getAddExpr(SE.getConstant(G->getType(), Offset), G); | |||
3407 | // If it cancelled out, drop the base register, otherwise update it. | |||
3408 | if (NewG->isZero()) { | |||
3409 | if (IsScaledReg) { | |||
3410 | F.Scale = 0; | |||
3411 | F.ScaledReg = nullptr; | |||
3412 | } else | |||
3413 | F.DeleteBaseReg(F.BaseRegs[Idx]); | |||
3414 | F.Canonicalize(); | |||
3415 | } else if (IsScaledReg) | |||
3416 | F.ScaledReg = NewG; | |||
3417 | else | |||
3418 | F.BaseRegs[Idx] = NewG; | |||
3419 | ||||
3420 | (void)InsertFormula(LU, LUIdx, F); | |||
3421 | } | |||
3422 | } | |||
3423 | ||||
3424 | int64_t Imm = ExtractImmediate(G, SE); | |||
3425 | if (G->isZero() || Imm == 0) | |||
3426 | return; | |||
3427 | Formula F = Base; | |||
3428 | F.BaseOffset = (uint64_t)F.BaseOffset + Imm; | |||
3429 | if (!isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, F)) | |||
3430 | return; | |||
3431 | if (IsScaledReg) | |||
3432 | F.ScaledReg = G; | |||
3433 | else | |||
3434 | F.BaseRegs[Idx] = G; | |||
3435 | (void)InsertFormula(LU, LUIdx, F); | |||
3436 | } | |||
3437 | ||||
3438 | /// GenerateConstantOffsets - Generate reuse formulae using symbolic offsets. | |||
3439 | void LSRInstance::GenerateConstantOffsets(LSRUse &LU, unsigned LUIdx, | |||
3440 | Formula Base) { | |||
3441 | // TODO: For now, just add the min and max offset, because it usually isn't | |||
3442 | // worthwhile looking at everything inbetween. | |||
3443 | SmallVector<int64_t, 2> Worklist; | |||
3444 | Worklist.push_back(LU.MinOffset); | |||
3445 | if (LU.MaxOffset != LU.MinOffset) | |||
3446 | Worklist.push_back(LU.MaxOffset); | |||
3447 | ||||
3448 | for (size_t i = 0, e = Base.BaseRegs.size(); i != e; ++i) | |||
3449 | GenerateConstantOffsetsImpl(LU, LUIdx, Base, Worklist, i); | |||
3450 | if (Base.Scale == 1) | |||
3451 | GenerateConstantOffsetsImpl(LU, LUIdx, Base, Worklist, /* Idx */ -1, | |||
3452 | /* IsScaledReg */ true); | |||
3453 | } | |||
3454 | ||||
3455 | /// GenerateICmpZeroScales - For ICmpZero, check to see if we can scale up | |||
3456 | /// the comparison. For example, x == y -> x*c == y*c. | |||
3457 | void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx, | |||
3458 | Formula Base) { | |||
3459 | if (LU.Kind != LSRUse::ICmpZero) return; | |||
3460 | ||||
3461 | // Determine the integer type for the base formula. | |||
3462 | Type *IntTy = Base.getType(); | |||
3463 | if (!IntTy) return; | |||
3464 | if (SE.getTypeSizeInBits(IntTy) > 64) return; | |||
3465 | ||||
3466 | // Don't do this if there is more than one offset. | |||
3467 | if (LU.MinOffset != LU.MaxOffset) return; | |||
3468 | ||||
3469 | assert(!Base.BaseGV && "ICmpZero use is not legal!")((!Base.BaseGV && "ICmpZero use is not legal!") ? static_cast <void> (0) : __assert_fail ("!Base.BaseGV && \"ICmpZero use is not legal!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 3469, __PRETTY_FUNCTION__)); | |||
3470 | ||||
3471 | // Check each interesting stride. | |||
3472 | for (int64_t Factor : Factors) { | |||
3473 | // Check that the multiplication doesn't overflow. | |||
3474 | if (Base.BaseOffset == INT64_MIN(-9223372036854775807L -1) && Factor == -1) | |||
3475 | continue; | |||
3476 | int64_t NewBaseOffset = (uint64_t)Base.BaseOffset * Factor; | |||
3477 | if (NewBaseOffset / Factor != Base.BaseOffset) | |||
3478 | continue; | |||
3479 | // If the offset will be truncated at this use, check that it is in bounds. | |||
3480 | if (!IntTy->isPointerTy() && | |||
3481 | !ConstantInt::isValueValidForType(IntTy, NewBaseOffset)) | |||
3482 | continue; | |||
3483 | ||||
3484 | // Check that multiplying with the use offset doesn't overflow. | |||
3485 | int64_t Offset = LU.MinOffset; | |||
3486 | if (Offset == INT64_MIN(-9223372036854775807L -1) && Factor == -1) | |||
3487 | continue; | |||
3488 | Offset = (uint64_t)Offset * Factor; | |||
3489 | if (Offset / Factor != LU.MinOffset) | |||
3490 | continue; | |||
3491 | // If the offset will be truncated at this use, check that it is in bounds. | |||
3492 | if (!IntTy->isPointerTy() && | |||
3493 | !ConstantInt::isValueValidForType(IntTy, Offset)) | |||
3494 | continue; | |||
3495 | ||||
3496 | Formula F = Base; | |||
3497 | F.BaseOffset = NewBaseOffset; | |||
3498 | ||||
3499 | // Check that this scale is legal. | |||
3500 | if (!isLegalUse(TTI, Offset, Offset, LU.Kind, LU.AccessTy, F)) | |||
3501 | continue; | |||
3502 | ||||
3503 | // Compensate for the use having MinOffset built into it. | |||
3504 | F.BaseOffset = (uint64_t)F.BaseOffset + Offset - LU.MinOffset; | |||
3505 | ||||
3506 | const SCEV *FactorS = SE.getConstant(IntTy, Factor); | |||
3507 | ||||
3508 | // Check that multiplying with each base register doesn't overflow. | |||
3509 | for (size_t i = 0, e = F.BaseRegs.size(); i != e; ++i) { | |||
3510 | F.BaseRegs[i] = SE.getMulExpr(F.BaseRegs[i], FactorS); | |||
3511 | if (getExactSDiv(F.BaseRegs[i], FactorS, SE) != Base.BaseRegs[i]) | |||
3512 | goto next; | |||
3513 | } | |||
3514 | ||||
3515 | // Check that multiplying with the scaled register doesn't overflow. | |||
3516 | if (F.ScaledReg) { | |||
3517 | F.ScaledReg = SE.getMulExpr(F.ScaledReg, FactorS); | |||
3518 | if (getExactSDiv(F.ScaledReg, FactorS, SE) != Base.ScaledReg) | |||
3519 | continue; | |||
3520 | } | |||
3521 | ||||
3522 | // Check that multiplying with the unfolded offset doesn't overflow. | |||
3523 | if (F.UnfoldedOffset != 0) { | |||
3524 | if (F.UnfoldedOffset == INT64_MIN(-9223372036854775807L -1) && Factor == -1) | |||
3525 | continue; | |||
3526 | F.UnfoldedOffset = (uint64_t)F.UnfoldedOffset * Factor; | |||
3527 | if (F.UnfoldedOffset / Factor != Base.UnfoldedOffset) | |||
3528 | continue; | |||
3529 | // If the offset will be truncated, check that it is in bounds. | |||
3530 | if (!IntTy->isPointerTy() && | |||
3531 | !ConstantInt::isValueValidForType(IntTy, F.UnfoldedOffset)) | |||
3532 | continue; | |||
3533 | } | |||
3534 | ||||
3535 | // If we make it here and it's legal, add it. | |||
3536 | (void)InsertFormula(LU, LUIdx, F); | |||
3537 | next:; | |||
3538 | } | |||
3539 | } | |||
3540 | ||||
3541 | /// GenerateScales - Generate stride factor reuse formulae by making use of | |||
3542 | /// scaled-offset address modes, for example. | |||
3543 | void LSRInstance::GenerateScales(LSRUse &LU, unsigned LUIdx, Formula Base) { | |||
3544 | // Determine the integer type for the base formula. | |||
3545 | Type *IntTy = Base.getType(); | |||
3546 | if (!IntTy) return; | |||
3547 | ||||
3548 | // If this Formula already has a scaled register, we can't add another one. | |||
3549 | // Try to unscale the formula to generate a better scale. | |||
3550 | if (Base.Scale != 0 && !Base.Unscale()) | |||
3551 | return; | |||
3552 | ||||
3553 | assert(Base.Scale == 0 && "Unscale did not did its job!")((Base.Scale == 0 && "Unscale did not did its job!") ? static_cast<void> (0) : __assert_fail ("Base.Scale == 0 && \"Unscale did not did its job!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 3553, __PRETTY_FUNCTION__)); | |||
3554 | ||||
3555 | // Check each interesting stride. | |||
3556 | for (int64_t Factor : Factors) { | |||
3557 | Base.Scale = Factor; | |||
3558 | Base.HasBaseReg = Base.BaseRegs.size() > 1; | |||
3559 | // Check whether this scale is going to be legal. | |||
3560 | if (!isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, | |||
3561 | Base)) { | |||
3562 | // As a special-case, handle special out-of-loop Basic users specially. | |||
3563 | // TODO: Reconsider this special case. | |||
3564 | if (LU.Kind == LSRUse::Basic && | |||
3565 | isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LSRUse::Special, | |||
3566 | LU.AccessTy, Base) && | |||
3567 | LU.AllFixupsOutsideLoop) | |||
3568 | LU.Kind = LSRUse::Special; | |||
3569 | else | |||
3570 | continue; | |||
3571 | } | |||
3572 | // For an ICmpZero, negating a solitary base register won't lead to | |||
3573 | // new solutions. | |||
3574 | if (LU.Kind == LSRUse::ICmpZero && | |||
3575 | !Base.HasBaseReg && Base.BaseOffset == 0 && !Base.BaseGV) | |||
3576 | continue; | |||
3577 | // For each addrec base reg, apply the scale, if possible. | |||
3578 | for (size_t i = 0, e = Base.BaseRegs.size(); i != e; ++i) | |||
3579 | if (const SCEVAddRecExpr *AR = | |||
3580 | dyn_cast<SCEVAddRecExpr>(Base.BaseRegs[i])) { | |||
3581 | const SCEV *FactorS = SE.getConstant(IntTy, Factor); | |||
3582 | if (FactorS->isZero()) | |||
3583 | continue; | |||
3584 | // Divide out the factor, ignoring high bits, since we'll be | |||
3585 | // scaling the value back up in the end. | |||
3586 | if (const SCEV *Quotient = getExactSDiv(AR, FactorS, SE, true)) { | |||
3587 | // TODO: This could be optimized to avoid all the copying. | |||
3588 | Formula F = Base; | |||
3589 | F.ScaledReg = Quotient; | |||
3590 | F.DeleteBaseReg(F.BaseRegs[i]); | |||
3591 | // The canonical representation of 1*reg is reg, which is already in | |||
3592 | // Base. In that case, do not try to insert the formula, it will be | |||
3593 | // rejected anyway. | |||
3594 | if (F.Scale == 1 && F.BaseRegs.empty()) | |||
3595 | continue; | |||
3596 | (void)InsertFormula(LU, LUIdx, F); | |||
3597 | } | |||
3598 | } | |||
3599 | } | |||
3600 | } | |||
3601 | ||||
3602 | /// GenerateTruncates - Generate reuse formulae from different IV types. | |||
3603 | void LSRInstance::GenerateTruncates(LSRUse &LU, unsigned LUIdx, Formula Base) { | |||
3604 | // Don't bother truncating symbolic values. | |||
3605 | if (Base.BaseGV) return; | |||
3606 | ||||
3607 | // Determine the integer type for the base formula. | |||
3608 | Type *DstTy = Base.getType(); | |||
3609 | if (!DstTy) return; | |||
3610 | DstTy = SE.getEffectiveSCEVType(DstTy); | |||
3611 | ||||
3612 | for (Type *SrcTy : Types) { | |||
3613 | if (SrcTy != DstTy && TTI.isTruncateFree(SrcTy, DstTy)) { | |||
3614 | Formula F = Base; | |||
3615 | ||||
3616 | if (F.ScaledReg) F.ScaledReg = SE.getAnyExtendExpr(F.ScaledReg, SrcTy); | |||
3617 | for (const SCEV *&BaseReg : F.BaseRegs) | |||
3618 | BaseReg = SE.getAnyExtendExpr(BaseReg, SrcTy); | |||
3619 | ||||
3620 | // TODO: This assumes we've done basic processing on all uses and | |||
3621 | // have an idea what the register usage is. | |||
3622 | if (!F.hasRegsUsedByUsesOtherThan(LUIdx, RegUses)) | |||
3623 | continue; | |||
3624 | ||||
3625 | (void)InsertFormula(LU, LUIdx, F); | |||
3626 | } | |||
3627 | } | |||
3628 | } | |||
3629 | ||||
3630 | namespace { | |||
3631 | ||||
3632 | /// WorkItem - Helper class for GenerateCrossUseConstantOffsets. It's used to | |||
3633 | /// defer modifications so that the search phase doesn't have to worry about | |||
3634 | /// the data structures moving underneath it. | |||
3635 | struct WorkItem { | |||
3636 | size_t LUIdx; | |||
3637 | int64_t Imm; | |||
3638 | const SCEV *OrigReg; | |||
3639 | ||||
3640 | WorkItem(size_t LI, int64_t I, const SCEV *R) | |||
3641 | : LUIdx(LI), Imm(I), OrigReg(R) {} | |||
3642 | ||||
3643 | void print(raw_ostream &OS) const; | |||
3644 | void dump() const; | |||
3645 | }; | |||
3646 | ||||
3647 | } | |||
3648 | ||||
3649 | void WorkItem::print(raw_ostream &OS) const { | |||
3650 | OS << "in formulae referencing " << *OrigReg << " in use " << LUIdx | |||
3651 | << " , add offset " << Imm; | |||
3652 | } | |||
3653 | ||||
3654 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | |||
3655 | void WorkItem::dump() const { | |||
3656 | print(errs()); errs() << '\n'; | |||
3657 | } | |||
3658 | #endif | |||
3659 | ||||
3660 | /// GenerateCrossUseConstantOffsets - Look for registers which are a constant | |||
3661 | /// distance apart and try to form reuse opportunities between them. | |||
3662 | void LSRInstance::GenerateCrossUseConstantOffsets() { | |||
3663 | // Group the registers by their value without any added constant offset. | |||
3664 | typedef std::map<int64_t, const SCEV *> ImmMapTy; | |||
3665 | DenseMap<const SCEV *, ImmMapTy> Map; | |||
3666 | DenseMap<const SCEV *, SmallBitVector> UsedByIndicesMap; | |||
3667 | SmallVector<const SCEV *, 8> Sequence; | |||
3668 | for (const SCEV *Use : RegUses) { | |||
3669 | const SCEV *Reg = Use; // Make a copy for ExtractImmediate to modify. | |||
3670 | int64_t Imm = ExtractImmediate(Reg, SE); | |||
3671 | auto Pair = Map.insert(std::make_pair(Reg, ImmMapTy())); | |||
3672 | if (Pair.second) | |||
3673 | Sequence.push_back(Reg); | |||
3674 | Pair.first->second.insert(std::make_pair(Imm, Use)); | |||
3675 | UsedByIndicesMap[Reg] |= RegUses.getUsedByIndices(Use); | |||
3676 | } | |||
3677 | ||||
3678 | // Now examine each set of registers with the same base value. Build up | |||
3679 | // a list of work to do and do the work in a separate step so that we're | |||
3680 | // not adding formulae and register counts while we're searching. | |||
3681 | SmallVector<WorkItem, 32> WorkItems; | |||
3682 | SmallSet<std::pair<size_t, int64_t>, 32> UniqueItems; | |||
3683 | for (const SCEV *Reg : Sequence) { | |||
3684 | const ImmMapTy &Imms = Map.find(Reg)->second; | |||
3685 | ||||
3686 | // It's not worthwhile looking for reuse if there's only one offset. | |||
3687 | if (Imms.size() == 1) | |||
3688 | continue; | |||
3689 | ||||
3690 | DEBUG(dbgs() << "Generating cross-use offsets for " << *Reg << ':';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Generating cross-use offsets for " << *Reg << ':'; for (const auto &Entry : Imms ) dbgs() << ' ' << Entry.first; dbgs() << '\n' ; } } while (0) | |||
3691 | for (const auto &Entry : Imms)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Generating cross-use offsets for " << *Reg << ':'; for (const auto &Entry : Imms ) dbgs() << ' ' << Entry.first; dbgs() << '\n' ; } } while (0) | |||
3692 | dbgs() << ' ' << Entry.first;do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Generating cross-use offsets for " << *Reg << ':'; for (const auto &Entry : Imms ) dbgs() << ' ' << Entry.first; dbgs() << '\n' ; } } while (0) | |||
3693 | dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Generating cross-use offsets for " << *Reg << ':'; for (const auto &Entry : Imms ) dbgs() << ' ' << Entry.first; dbgs() << '\n' ; } } while (0); | |||
3694 | ||||
3695 | // Examine each offset. | |||
3696 | for (ImmMapTy::const_iterator J = Imms.begin(), JE = Imms.end(); | |||
3697 | J != JE; ++J) { | |||
3698 | const SCEV *OrigReg = J->second; | |||
3699 | ||||
3700 | int64_t JImm = J->first; | |||
3701 | const SmallBitVector &UsedByIndices = RegUses.getUsedByIndices(OrigReg); | |||
3702 | ||||
3703 | if (!isa<SCEVConstant>(OrigReg) && | |||
3704 | UsedByIndicesMap[Reg].count() == 1) { | |||
3705 | DEBUG(dbgs() << "Skipping cross-use reuse for " << *OrigReg << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Skipping cross-use reuse for " << *OrigReg << '\n'; } } while (0); | |||
3706 | continue; | |||
3707 | } | |||
3708 | ||||
3709 | // Conservatively examine offsets between this orig reg a few selected | |||
3710 | // other orig regs. | |||
3711 | ImmMapTy::const_iterator OtherImms[] = { | |||
3712 | Imms.begin(), std::prev(Imms.end()), | |||
3713 | Imms.lower_bound((Imms.begin()->first + std::prev(Imms.end())->first) / | |||
3714 | 2) | |||
3715 | }; | |||
3716 | for (size_t i = 0, e = array_lengthof(OtherImms); i != e; ++i) { | |||
3717 | ImmMapTy::const_iterator M = OtherImms[i]; | |||
3718 | if (M == J || M == JE) continue; | |||
3719 | ||||
3720 | // Compute the difference between the two. | |||
3721 | int64_t Imm = (uint64_t)JImm - M->first; | |||
3722 | for (int LUIdx = UsedByIndices.find_first(); LUIdx != -1; | |||
3723 | LUIdx = UsedByIndices.find_next(LUIdx)) | |||
3724 | // Make a memo of this use, offset, and register tuple. | |||
3725 | if (UniqueItems.insert(std::make_pair(LUIdx, Imm)).second) | |||
3726 | WorkItems.push_back(WorkItem(LUIdx, Imm, OrigReg)); | |||
3727 | } | |||
3728 | } | |||
3729 | } | |||
3730 | ||||
3731 | Map.clear(); | |||
3732 | Sequence.clear(); | |||
3733 | UsedByIndicesMap.clear(); | |||
3734 | UniqueItems.clear(); | |||
3735 | ||||
3736 | // Now iterate through the worklist and add new formulae. | |||
3737 | for (const WorkItem &WI : WorkItems) { | |||
3738 | size_t LUIdx = WI.LUIdx; | |||
3739 | LSRUse &LU = Uses[LUIdx]; | |||
3740 | int64_t Imm = WI.Imm; | |||
3741 | const SCEV *OrigReg = WI.OrigReg; | |||
3742 | ||||
3743 | Type *IntTy = SE.getEffectiveSCEVType(OrigReg->getType()); | |||
3744 | const SCEV *NegImmS = SE.getSCEV(ConstantInt::get(IntTy, -(uint64_t)Imm)); | |||
3745 | unsigned BitWidth = SE.getTypeSizeInBits(IntTy); | |||
3746 | ||||
3747 | // TODO: Use a more targeted data structure. | |||
3748 | for (size_t L = 0, LE = LU.Formulae.size(); L != LE; ++L) { | |||
3749 | Formula F = LU.Formulae[L]; | |||
3750 | // FIXME: The code for the scaled and unscaled registers looks | |||
3751 | // very similar but slightly different. Investigate if they | |||
3752 | // could be merged. That way, we would not have to unscale the | |||
3753 | // Formula. | |||
3754 | F.Unscale(); | |||
3755 | // Use the immediate in the scaled register. | |||
3756 | if (F.ScaledReg == OrigReg) { | |||
3757 | int64_t Offset = (uint64_t)F.BaseOffset + Imm * (uint64_t)F.Scale; | |||
3758 | // Don't create 50 + reg(-50). | |||
3759 | if (F.referencesReg(SE.getSCEV( | |||
3760 | ConstantInt::get(IntTy, -(uint64_t)Offset)))) | |||
3761 | continue; | |||
3762 | Formula NewF = F; | |||
3763 | NewF.BaseOffset = Offset; | |||
3764 | if (!isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, | |||
3765 | NewF)) | |||
3766 | continue; | |||
3767 | NewF.ScaledReg = SE.getAddExpr(NegImmS, NewF.ScaledReg); | |||
3768 | ||||
3769 | // If the new scale is a constant in a register, and adding the constant | |||
3770 | // value to the immediate would produce a value closer to zero than the | |||
3771 | // immediate itself, then the formula isn't worthwhile. | |||
3772 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(NewF.ScaledReg)) | |||
3773 | if (C->getValue()->isNegative() != | |||
3774 | (NewF.BaseOffset < 0) && | |||
3775 | (C->getValue()->getValue().abs() * APInt(BitWidth, F.Scale)) | |||
3776 | .ule(std::abs(NewF.BaseOffset))) | |||
3777 | continue; | |||
3778 | ||||
3779 | // OK, looks good. | |||
3780 | NewF.Canonicalize(); | |||
3781 | (void)InsertFormula(LU, LUIdx, NewF); | |||
3782 | } else { | |||
3783 | // Use the immediate in a base register. | |||
3784 | for (size_t N = 0, NE = F.BaseRegs.size(); N != NE; ++N) { | |||
3785 | const SCEV *BaseReg = F.BaseRegs[N]; | |||
3786 | if (BaseReg != OrigReg) | |||
3787 | continue; | |||
3788 | Formula NewF = F; | |||
3789 | NewF.BaseOffset = (uint64_t)NewF.BaseOffset + Imm; | |||
3790 | if (!isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, | |||
3791 | LU.Kind, LU.AccessTy, NewF)) { | |||
3792 | if (!TTI.isLegalAddImmediate((uint64_t)NewF.UnfoldedOffset + Imm)) | |||
3793 | continue; | |||
3794 | NewF = F; | |||
3795 | NewF.UnfoldedOffset = (uint64_t)NewF.UnfoldedOffset + Imm; | |||
3796 | } | |||
3797 | NewF.BaseRegs[N] = SE.getAddExpr(NegImmS, BaseReg); | |||
3798 | ||||
3799 | // If the new formula has a constant in a register, and adding the | |||
3800 | // constant value to the immediate would produce a value closer to | |||
3801 | // zero than the immediate itself, then the formula isn't worthwhile. | |||
3802 | for (const SCEV *NewReg : NewF.BaseRegs) | |||
3803 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(NewReg)) | |||
3804 | if ((C->getValue()->getValue() + NewF.BaseOffset).abs().slt( | |||
3805 | std::abs(NewF.BaseOffset)) && | |||
3806 | (C->getValue()->getValue() + | |||
3807 | NewF.BaseOffset).countTrailingZeros() >= | |||
3808 | countTrailingZeros<uint64_t>(NewF.BaseOffset)) | |||
3809 | goto skip_formula; | |||
3810 | ||||
3811 | // Ok, looks good. | |||
3812 | NewF.Canonicalize(); | |||
3813 | (void)InsertFormula(LU, LUIdx, NewF); | |||
3814 | break; | |||
3815 | skip_formula:; | |||
3816 | } | |||
3817 | } | |||
3818 | } | |||
3819 | } | |||
3820 | } | |||
3821 | ||||
3822 | /// GenerateAllReuseFormulae - Generate formulae for each use. | |||
3823 | void | |||
3824 | LSRInstance::GenerateAllReuseFormulae() { | |||
3825 | // This is split into multiple loops so that hasRegsUsedByUsesOtherThan | |||
3826 | // queries are more precise. | |||
3827 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
3828 | LSRUse &LU = Uses[LUIdx]; | |||
3829 | for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i) | |||
3830 | GenerateReassociations(LU, LUIdx, LU.Formulae[i]); | |||
3831 | for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i) | |||
3832 | GenerateCombinations(LU, LUIdx, LU.Formulae[i]); | |||
3833 | } | |||
3834 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
3835 | LSRUse &LU = Uses[LUIdx]; | |||
3836 | for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i) | |||
3837 | GenerateSymbolicOffsets(LU, LUIdx, LU.Formulae[i]); | |||
3838 | for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i) | |||
3839 | GenerateConstantOffsets(LU, LUIdx, LU.Formulae[i]); | |||
3840 | for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i) | |||
3841 | GenerateICmpZeroScales(LU, LUIdx, LU.Formulae[i]); | |||
3842 | for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i) | |||
3843 | GenerateScales(LU, LUIdx, LU.Formulae[i]); | |||
3844 | } | |||
3845 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
3846 | LSRUse &LU = Uses[LUIdx]; | |||
3847 | for (size_t i = 0, f = LU.Formulae.size(); i != f; ++i) | |||
3848 | GenerateTruncates(LU, LUIdx, LU.Formulae[i]); | |||
3849 | } | |||
3850 | ||||
3851 | GenerateCrossUseConstantOffsets(); | |||
3852 | ||||
3853 | DEBUG(dbgs() << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "After generating reuse formulae:\n" ; print_uses(dbgs()); } } while (0) | |||
3854 | "After generating reuse formulae:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "After generating reuse formulae:\n" ; print_uses(dbgs()); } } while (0) | |||
3855 | print_uses(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "After generating reuse formulae:\n" ; print_uses(dbgs()); } } while (0); | |||
3856 | } | |||
3857 | ||||
3858 | /// If there are multiple formulae with the same set of registers used | |||
3859 | /// by other uses, pick the best one and delete the others. | |||
3860 | void LSRInstance::FilterOutUndesirableDedicatedRegisters() { | |||
3861 | DenseSet<const SCEV *> VisitedRegs; | |||
3862 | SmallPtrSet<const SCEV *, 16> Regs; | |||
3863 | SmallPtrSet<const SCEV *, 16> LoserRegs; | |||
3864 | #ifndef NDEBUG | |||
3865 | bool ChangedFormulae = false; | |||
3866 | #endif | |||
3867 | ||||
3868 | // Collect the best formula for each unique set of shared registers. This | |||
3869 | // is reset for each use. | |||
3870 | typedef DenseMap<SmallVector<const SCEV *, 4>, size_t, UniquifierDenseMapInfo> | |||
3871 | BestFormulaeTy; | |||
3872 | BestFormulaeTy BestFormulae; | |||
3873 | ||||
3874 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
3875 | LSRUse &LU = Uses[LUIdx]; | |||
3876 | DEBUG(dbgs() << "Filtering for use "; LU.print(dbgs()); dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Filtering for use "; LU.print (dbgs()); dbgs() << '\n'; } } while (0); | |||
3877 | ||||
3878 | bool Any = false; | |||
3879 | for (size_t FIdx = 0, NumForms = LU.Formulae.size(); | |||
3880 | FIdx != NumForms; ++FIdx) { | |||
3881 | Formula &F = LU.Formulae[FIdx]; | |||
3882 | ||||
3883 | // Some formulas are instant losers. For example, they may depend on | |||
3884 | // nonexistent AddRecs from other loops. These need to be filtered | |||
3885 | // immediately, otherwise heuristics could choose them over others leading | |||
3886 | // to an unsatisfactory solution. Passing LoserRegs into RateFormula here | |||
3887 | // avoids the need to recompute this information across formulae using the | |||
3888 | // same bad AddRec. Passing LoserRegs is also essential unless we remove | |||
3889 | // the corresponding bad register from the Regs set. | |||
3890 | Cost CostF; | |||
3891 | Regs.clear(); | |||
3892 | CostF.RateFormula(TTI, F, Regs, VisitedRegs, L, LU.Offsets, SE, DT, LU, | |||
3893 | &LoserRegs); | |||
3894 | if (CostF.isLoser()) { | |||
3895 | // During initial formula generation, undesirable formulae are generated | |||
3896 | // by uses within other loops that have some non-trivial address mode or | |||
3897 | // use the postinc form of the IV. LSR needs to provide these formulae | |||
3898 | // as the basis of rediscovering the desired formula that uses an AddRec | |||
3899 | // corresponding to the existing phi. Once all formulae have been | |||
3900 | // generated, these initial losers may be pruned. | |||
3901 | DEBUG(dbgs() << " Filtering loser "; F.print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Filtering loser "; F.print (dbgs()); dbgs() << "\n"; } } while (0) | |||
3902 | dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Filtering loser "; F.print (dbgs()); dbgs() << "\n"; } } while (0); | |||
3903 | } | |||
3904 | else { | |||
3905 | SmallVector<const SCEV *, 4> Key; | |||
3906 | for (const SCEV *Reg : F.BaseRegs) { | |||
3907 | if (RegUses.isRegUsedByUsesOtherThan(Reg, LUIdx)) | |||
3908 | Key.push_back(Reg); | |||
3909 | } | |||
3910 | if (F.ScaledReg && | |||
3911 | RegUses.isRegUsedByUsesOtherThan(F.ScaledReg, LUIdx)) | |||
3912 | Key.push_back(F.ScaledReg); | |||
3913 | // Unstable sort by host order ok, because this is only used for | |||
3914 | // uniquifying. | |||
3915 | std::sort(Key.begin(), Key.end()); | |||
3916 | ||||
3917 | std::pair<BestFormulaeTy::const_iterator, bool> P = | |||
3918 | BestFormulae.insert(std::make_pair(Key, FIdx)); | |||
3919 | if (P.second) | |||
3920 | continue; | |||
3921 | ||||
3922 | Formula &Best = LU.Formulae[P.first->second]; | |||
3923 | ||||
3924 | Cost CostBest; | |||
3925 | Regs.clear(); | |||
3926 | CostBest.RateFormula(TTI, Best, Regs, VisitedRegs, L, LU.Offsets, SE, | |||
3927 | DT, LU); | |||
3928 | if (CostF < CostBest) | |||
3929 | std::swap(F, Best); | |||
3930 | DEBUG(dbgs() << " Filtering out formula "; F.print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Filtering out formula " ; F.print(dbgs()); dbgs() << "\n" " in favor of formula " ; Best.print(dbgs()); dbgs() << '\n'; } } while (0) | |||
3931 | dbgs() << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Filtering out formula " ; F.print(dbgs()); dbgs() << "\n" " in favor of formula " ; Best.print(dbgs()); dbgs() << '\n'; } } while (0) | |||
3932 | " in favor of formula "; Best.print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Filtering out formula " ; F.print(dbgs()); dbgs() << "\n" " in favor of formula " ; Best.print(dbgs()); dbgs() << '\n'; } } while (0) | |||
3933 | dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Filtering out formula " ; F.print(dbgs()); dbgs() << "\n" " in favor of formula " ; Best.print(dbgs()); dbgs() << '\n'; } } while (0); | |||
3934 | } | |||
3935 | #ifndef NDEBUG | |||
3936 | ChangedFormulae = true; | |||
3937 | #endif | |||
3938 | LU.DeleteFormula(F); | |||
3939 | --FIdx; | |||
3940 | --NumForms; | |||
3941 | Any = true; | |||
3942 | } | |||
3943 | ||||
3944 | // Now that we've filtered out some formulae, recompute the Regs set. | |||
3945 | if (Any) | |||
3946 | LU.RecomputeRegs(LUIdx, RegUses); | |||
3947 | ||||
3948 | // Reset this to prepare for the next use. | |||
3949 | BestFormulae.clear(); | |||
3950 | } | |||
3951 | ||||
3952 | DEBUG(if (ChangedFormulae) {do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { if (ChangedFormulae) { dbgs() << "\n" "After filtering out undesirable candidates:\n"; print_uses( dbgs()); }; } } while (0) | |||
3953 | dbgs() << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { if (ChangedFormulae) { dbgs() << "\n" "After filtering out undesirable candidates:\n"; print_uses( dbgs()); }; } } while (0) | |||
3954 | "After filtering out undesirable candidates:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { if (ChangedFormulae) { dbgs() << "\n" "After filtering out undesirable candidates:\n"; print_uses( dbgs()); }; } } while (0) | |||
3955 | print_uses(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { if (ChangedFormulae) { dbgs() << "\n" "After filtering out undesirable candidates:\n"; print_uses( dbgs()); }; } } while (0) | |||
3956 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { if (ChangedFormulae) { dbgs() << "\n" "After filtering out undesirable candidates:\n"; print_uses( dbgs()); }; } } while (0); | |||
3957 | } | |||
3958 | ||||
3959 | // This is a rough guess that seems to work fairly well. | |||
3960 | static const size_t ComplexityLimit = UINT16_MAX(65535); | |||
3961 | ||||
3962 | /// EstimateSearchSpaceComplexity - Estimate the worst-case number of | |||
3963 | /// solutions the solver might have to consider. It almost never considers | |||
3964 | /// this many solutions because it prune the search space, but the pruning | |||
3965 | /// isn't always sufficient. | |||
3966 | size_t LSRInstance::EstimateSearchSpaceComplexity() const { | |||
3967 | size_t Power = 1; | |||
3968 | for (const LSRUse &LU : Uses) { | |||
3969 | size_t FSize = LU.Formulae.size(); | |||
3970 | if (FSize >= ComplexityLimit) { | |||
3971 | Power = ComplexityLimit; | |||
3972 | break; | |||
3973 | } | |||
3974 | Power *= FSize; | |||
3975 | if (Power >= ComplexityLimit) | |||
3976 | break; | |||
3977 | } | |||
3978 | return Power; | |||
3979 | } | |||
3980 | ||||
3981 | /// NarrowSearchSpaceByDetectingSupersets - When one formula uses a superset | |||
3982 | /// of the registers of another formula, it won't help reduce register | |||
3983 | /// pressure (though it may not necessarily hurt register pressure); remove | |||
3984 | /// it to simplify the system. | |||
3985 | void LSRInstance::NarrowSearchSpaceByDetectingSupersets() { | |||
3986 | if (EstimateSearchSpaceComplexity() >= ComplexityLimit) { | |||
3987 | DEBUG(dbgs() << "The search space is too complex.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "The search space is too complex.\n" ; } } while (0); | |||
3988 | ||||
3989 | DEBUG(dbgs() << "Narrowing the search space by eliminating formulae "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Narrowing the search space by eliminating formulae " "which use a superset of registers used by other " "formulae.\n" ; } } while (0) | |||
3990 | "which use a superset of registers used by other "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Narrowing the search space by eliminating formulae " "which use a superset of registers used by other " "formulae.\n" ; } } while (0) | |||
3991 | "formulae.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Narrowing the search space by eliminating formulae " "which use a superset of registers used by other " "formulae.\n" ; } } while (0); | |||
3992 | ||||
3993 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
3994 | LSRUse &LU = Uses[LUIdx]; | |||
3995 | bool Any = false; | |||
3996 | for (size_t i = 0, e = LU.Formulae.size(); i != e; ++i) { | |||
3997 | Formula &F = LU.Formulae[i]; | |||
3998 | // Look for a formula with a constant or GV in a register. If the use | |||
3999 | // also has a formula with that same value in an immediate field, | |||
4000 | // delete the one that uses a register. | |||
4001 | for (SmallVectorImpl<const SCEV *>::const_iterator | |||
4002 | I = F.BaseRegs.begin(), E = F.BaseRegs.end(); I != E; ++I) { | |||
4003 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(*I)) { | |||
4004 | Formula NewF = F; | |||
4005 | NewF.BaseOffset += C->getValue()->getSExtValue(); | |||
4006 | NewF.BaseRegs.erase(NewF.BaseRegs.begin() + | |||
4007 | (I - F.BaseRegs.begin())); | |||
4008 | if (LU.HasFormulaWithSameRegs(NewF)) { | |||
4009 | DEBUG(dbgs() << " Deleting "; F.print(dbgs()); dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Deleting "; F.print(dbgs ()); dbgs() << '\n'; } } while (0); | |||
4010 | LU.DeleteFormula(F); | |||
4011 | --i; | |||
4012 | --e; | |||
4013 | Any = true; | |||
4014 | break; | |||
4015 | } | |||
4016 | } else if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(*I)) { | |||
4017 | if (GlobalValue *GV = dyn_cast<GlobalValue>(U->getValue())) | |||
4018 | if (!F.BaseGV) { | |||
4019 | Formula NewF = F; | |||
4020 | NewF.BaseGV = GV; | |||
4021 | NewF.BaseRegs.erase(NewF.BaseRegs.begin() + | |||
4022 | (I - F.BaseRegs.begin())); | |||
4023 | if (LU.HasFormulaWithSameRegs(NewF)) { | |||
4024 | DEBUG(dbgs() << " Deleting "; F.print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Deleting "; F.print(dbgs ()); dbgs() << '\n'; } } while (0) | |||
4025 | dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Deleting "; F.print(dbgs ()); dbgs() << '\n'; } } while (0); | |||
4026 | LU.DeleteFormula(F); | |||
4027 | --i; | |||
4028 | --e; | |||
4029 | Any = true; | |||
4030 | break; | |||
4031 | } | |||
4032 | } | |||
4033 | } | |||
4034 | } | |||
4035 | } | |||
4036 | if (Any) | |||
4037 | LU.RecomputeRegs(LUIdx, RegUses); | |||
4038 | } | |||
4039 | ||||
4040 | DEBUG(dbgs() << "After pre-selection:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "After pre-selection:\n"; print_uses (dbgs()); } } while (0) | |||
4041 | print_uses(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "After pre-selection:\n"; print_uses (dbgs()); } } while (0); | |||
4042 | } | |||
4043 | } | |||
4044 | ||||
4045 | /// NarrowSearchSpaceByCollapsingUnrolledCode - When there are many registers | |||
4046 | /// for expressions like A, A+1, A+2, etc., allocate a single register for | |||
4047 | /// them. | |||
4048 | void LSRInstance::NarrowSearchSpaceByCollapsingUnrolledCode() { | |||
4049 | if (EstimateSearchSpaceComplexity() < ComplexityLimit) | |||
4050 | return; | |||
4051 | ||||
4052 | DEBUG(dbgs() << "The search space is too complex.\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "The search space is too complex.\n" "Narrowing the search space by assuming that uses separated " "by a constant offset will use the same registers.\n"; } } while (0) | |||
4053 | "Narrowing the search space by assuming that uses separated "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "The search space is too complex.\n" "Narrowing the search space by assuming that uses separated " "by a constant offset will use the same registers.\n"; } } while (0) | |||
4054 | "by a constant offset will use the same registers.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "The search space is too complex.\n" "Narrowing the search space by assuming that uses separated " "by a constant offset will use the same registers.\n"; } } while (0); | |||
4055 | ||||
4056 | // This is especially useful for unrolled loops. | |||
4057 | ||||
4058 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
4059 | LSRUse &LU = Uses[LUIdx]; | |||
4060 | for (const Formula &F : LU.Formulae) { | |||
4061 | if (F.BaseOffset == 0 || (F.Scale != 0 && F.Scale != 1)) | |||
4062 | continue; | |||
4063 | ||||
4064 | LSRUse *LUThatHas = FindUseWithSimilarFormula(F, LU); | |||
4065 | if (!LUThatHas) | |||
4066 | continue; | |||
4067 | ||||
4068 | if (!reconcileNewOffset(*LUThatHas, F.BaseOffset, /*HasBaseReg=*/ false, | |||
4069 | LU.Kind, LU.AccessTy)) | |||
4070 | continue; | |||
4071 | ||||
4072 | DEBUG(dbgs() << " Deleting use "; LU.print(dbgs()); dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Deleting use "; LU.print (dbgs()); dbgs() << '\n'; } } while (0); | |||
4073 | ||||
4074 | LUThatHas->AllFixupsOutsideLoop &= LU.AllFixupsOutsideLoop; | |||
4075 | ||||
4076 | // Update the relocs to reference the new use. | |||
4077 | for (LSRFixup &Fixup : Fixups) { | |||
4078 | if (Fixup.LUIdx == LUIdx) { | |||
4079 | Fixup.LUIdx = LUThatHas - &Uses.front(); | |||
4080 | Fixup.Offset += F.BaseOffset; | |||
4081 | // Add the new offset to LUThatHas' offset list. | |||
4082 | if (LUThatHas->Offsets.back() != Fixup.Offset) { | |||
4083 | LUThatHas->Offsets.push_back(Fixup.Offset); | |||
4084 | if (Fixup.Offset > LUThatHas->MaxOffset) | |||
4085 | LUThatHas->MaxOffset = Fixup.Offset; | |||
4086 | if (Fixup.Offset < LUThatHas->MinOffset) | |||
4087 | LUThatHas->MinOffset = Fixup.Offset; | |||
4088 | } | |||
4089 | DEBUG(dbgs() << "New fixup has offset " << Fixup.Offset << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "New fixup has offset " << Fixup.Offset << '\n'; } } while (0); | |||
4090 | } | |||
4091 | if (Fixup.LUIdx == NumUses-1) | |||
4092 | Fixup.LUIdx = LUIdx; | |||
4093 | } | |||
4094 | ||||
4095 | // Delete formulae from the new use which are no longer legal. | |||
4096 | bool Any = false; | |||
4097 | for (size_t i = 0, e = LUThatHas->Formulae.size(); i != e; ++i) { | |||
4098 | Formula &F = LUThatHas->Formulae[i]; | |||
4099 | if (!isLegalUse(TTI, LUThatHas->MinOffset, LUThatHas->MaxOffset, | |||
4100 | LUThatHas->Kind, LUThatHas->AccessTy, F)) { | |||
4101 | DEBUG(dbgs() << " Deleting "; F.print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Deleting "; F.print(dbgs ()); dbgs() << '\n'; } } while (0) | |||
4102 | dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Deleting "; F.print(dbgs ()); dbgs() << '\n'; } } while (0); | |||
4103 | LUThatHas->DeleteFormula(F); | |||
4104 | --i; | |||
4105 | --e; | |||
4106 | Any = true; | |||
4107 | } | |||
4108 | } | |||
4109 | ||||
4110 | if (Any) | |||
4111 | LUThatHas->RecomputeRegs(LUThatHas - &Uses.front(), RegUses); | |||
4112 | ||||
4113 | // Delete the old use. | |||
4114 | DeleteUse(LU, LUIdx); | |||
4115 | --LUIdx; | |||
4116 | --NumUses; | |||
4117 | break; | |||
4118 | } | |||
4119 | } | |||
4120 | ||||
4121 | DEBUG(dbgs() << "After pre-selection:\n"; print_uses(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "After pre-selection:\n"; print_uses (dbgs()); } } while (0); | |||
4122 | } | |||
4123 | ||||
4124 | /// NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters - Call | |||
4125 | /// FilterOutUndesirableDedicatedRegisters again, if necessary, now that | |||
4126 | /// we've done more filtering, as it may be able to find more formulae to | |||
4127 | /// eliminate. | |||
4128 | void LSRInstance::NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters(){ | |||
4129 | if (EstimateSearchSpaceComplexity() >= ComplexityLimit) { | |||
4130 | DEBUG(dbgs() << "The search space is too complex.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "The search space is too complex.\n" ; } } while (0); | |||
4131 | ||||
4132 | DEBUG(dbgs() << "Narrowing the search space by re-filtering out "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Narrowing the search space by re-filtering out " "undesirable dedicated registers.\n"; } } while (0) | |||
4133 | "undesirable dedicated registers.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Narrowing the search space by re-filtering out " "undesirable dedicated registers.\n"; } } while (0); | |||
4134 | ||||
4135 | FilterOutUndesirableDedicatedRegisters(); | |||
4136 | ||||
4137 | DEBUG(dbgs() << "After pre-selection:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "After pre-selection:\n"; print_uses (dbgs()); } } while (0) | |||
4138 | print_uses(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "After pre-selection:\n"; print_uses (dbgs()); } } while (0); | |||
4139 | } | |||
4140 | } | |||
4141 | ||||
4142 | /// NarrowSearchSpaceByPickingWinnerRegs - Pick a register which seems likely | |||
4143 | /// to be profitable, and then in any use which has any reference to that | |||
4144 | /// register, delete all formulae which do not reference that register. | |||
4145 | void LSRInstance::NarrowSearchSpaceByPickingWinnerRegs() { | |||
4146 | // With all other options exhausted, loop until the system is simple | |||
4147 | // enough to handle. | |||
4148 | SmallPtrSet<const SCEV *, 4> Taken; | |||
4149 | while (EstimateSearchSpaceComplexity() >= ComplexityLimit) { | |||
4150 | // Ok, we have too many of formulae on our hands to conveniently handle. | |||
4151 | // Use a rough heuristic to thin out the list. | |||
4152 | DEBUG(dbgs() << "The search space is too complex.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "The search space is too complex.\n" ; } } while (0); | |||
4153 | ||||
4154 | // Pick the register which is used by the most LSRUses, which is likely | |||
4155 | // to be a good reuse register candidate. | |||
4156 | const SCEV *Best = nullptr; | |||
4157 | unsigned BestNum = 0; | |||
4158 | for (const SCEV *Reg : RegUses) { | |||
4159 | if (Taken.count(Reg)) | |||
4160 | continue; | |||
4161 | if (!Best) | |||
4162 | Best = Reg; | |||
4163 | else { | |||
4164 | unsigned Count = RegUses.getUsedByIndices(Reg).count(); | |||
4165 | if (Count > BestNum) { | |||
4166 | Best = Reg; | |||
4167 | BestNum = Count; | |||
4168 | } | |||
4169 | } | |||
4170 | } | |||
4171 | ||||
4172 | DEBUG(dbgs() << "Narrowing the search space by assuming " << *Bestdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Narrowing the search space by assuming " << *Best << " will yield profitable reuse.\n"; } } while (0) | |||
4173 | << " will yield profitable reuse.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "Narrowing the search space by assuming " << *Best << " will yield profitable reuse.\n"; } } while (0); | |||
4174 | Taken.insert(Best); | |||
4175 | ||||
4176 | // In any use with formulae which references this register, delete formulae | |||
4177 | // which don't reference it. | |||
4178 | for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) { | |||
4179 | LSRUse &LU = Uses[LUIdx]; | |||
4180 | if (!LU.Regs.count(Best)) continue; | |||
4181 | ||||
4182 | bool Any = false; | |||
4183 | for (size_t i = 0, e = LU.Formulae.size(); i != e; ++i) { | |||
4184 | Formula &F = LU.Formulae[i]; | |||
4185 | if (!F.referencesReg(Best)) { | |||
4186 | DEBUG(dbgs() << " Deleting "; F.print(dbgs()); dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << " Deleting "; F.print(dbgs ()); dbgs() << '\n'; } } while (0); | |||
4187 | LU.DeleteFormula(F); | |||
4188 | --e; | |||
4189 | --i; | |||
4190 | Any = true; | |||
4191 | assert(e != 0 && "Use has no formulae left! Is Regs inconsistent?")((e != 0 && "Use has no formulae left! Is Regs inconsistent?" ) ? static_cast<void> (0) : __assert_fail ("e != 0 && \"Use has no formulae left! Is Regs inconsistent?\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4191, __PRETTY_FUNCTION__)); | |||
4192 | continue; | |||
4193 | } | |||
4194 | } | |||
4195 | ||||
4196 | if (Any) | |||
4197 | LU.RecomputeRegs(LUIdx, RegUses); | |||
4198 | } | |||
4199 | ||||
4200 | DEBUG(dbgs() << "After pre-selection:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "After pre-selection:\n"; print_uses (dbgs()); } } while (0) | |||
4201 | print_uses(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "After pre-selection:\n"; print_uses (dbgs()); } } while (0); | |||
4202 | } | |||
4203 | } | |||
4204 | ||||
4205 | /// NarrowSearchSpaceUsingHeuristics - If there are an extraordinary number of | |||
4206 | /// formulae to choose from, use some rough heuristics to prune down the number | |||
4207 | /// of formulae. This keeps the main solver from taking an extraordinary amount | |||
4208 | /// of time in some worst-case scenarios. | |||
4209 | void LSRInstance::NarrowSearchSpaceUsingHeuristics() { | |||
4210 | NarrowSearchSpaceByDetectingSupersets(); | |||
4211 | NarrowSearchSpaceByCollapsingUnrolledCode(); | |||
4212 | NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters(); | |||
4213 | NarrowSearchSpaceByPickingWinnerRegs(); | |||
4214 | } | |||
4215 | ||||
4216 | /// SolveRecurse - This is the recursive solver. | |||
4217 | void LSRInstance::SolveRecurse(SmallVectorImpl<const Formula *> &Solution, | |||
4218 | Cost &SolutionCost, | |||
4219 | SmallVectorImpl<const Formula *> &Workspace, | |||
4220 | const Cost &CurCost, | |||
4221 | const SmallPtrSet<const SCEV *, 16> &CurRegs, | |||
4222 | DenseSet<const SCEV *> &VisitedRegs) const { | |||
4223 | // Some ideas: | |||
4224 | // - prune more: | |||
4225 | // - use more aggressive filtering | |||
4226 | // - sort the formula so that the most profitable solutions are found first | |||
4227 | // - sort the uses too | |||
4228 | // - search faster: | |||
4229 | // - don't compute a cost, and then compare. compare while computing a cost | |||
4230 | // and bail early. | |||
4231 | // - track register sets with SmallBitVector | |||
4232 | ||||
4233 | const LSRUse &LU = Uses[Workspace.size()]; | |||
4234 | ||||
4235 | // If this use references any register that's already a part of the | |||
4236 | // in-progress solution, consider it a requirement that a formula must | |||
4237 | // reference that register in order to be considered. This prunes out | |||
4238 | // unprofitable searching. | |||
4239 | SmallSetVector<const SCEV *, 4> ReqRegs; | |||
4240 | for (const SCEV *S : CurRegs) | |||
4241 | if (LU.Regs.count(S)) | |||
4242 | ReqRegs.insert(S); | |||
4243 | ||||
4244 | SmallPtrSet<const SCEV *, 16> NewRegs; | |||
4245 | Cost NewCost; | |||
4246 | for (const Formula &F : LU.Formulae) { | |||
4247 | // Ignore formulae which may not be ideal in terms of register reuse of | |||
4248 | // ReqRegs. The formula should use all required registers before | |||
4249 | // introducing new ones. | |||
4250 | int NumReqRegsToFind = std::min(F.getNumRegs(), ReqRegs.size()); | |||
4251 | for (const SCEV *Reg : ReqRegs) { | |||
4252 | if ((F.ScaledReg && F.ScaledReg == Reg) || | |||
4253 | std::find(F.BaseRegs.begin(), F.BaseRegs.end(), Reg) != | |||
4254 | F.BaseRegs.end()) { | |||
4255 | --NumReqRegsToFind; | |||
4256 | if (NumReqRegsToFind == 0) | |||
4257 | break; | |||
4258 | } | |||
4259 | } | |||
4260 | if (NumReqRegsToFind != 0) { | |||
4261 | // If none of the formulae satisfied the required registers, then we could | |||
4262 | // clear ReqRegs and try again. Currently, we simply give up in this case. | |||
4263 | continue; | |||
4264 | } | |||
4265 | ||||
4266 | // Evaluate the cost of the current formula. If it's already worse than | |||
4267 | // the current best, prune the search at that point. | |||
4268 | NewCost = CurCost; | |||
4269 | NewRegs = CurRegs; | |||
4270 | NewCost.RateFormula(TTI, F, NewRegs, VisitedRegs, L, LU.Offsets, SE, DT, | |||
4271 | LU); | |||
4272 | if (NewCost < SolutionCost) { | |||
4273 | Workspace.push_back(&F); | |||
4274 | if (Workspace.size() != Uses.size()) { | |||
4275 | SolveRecurse(Solution, SolutionCost, Workspace, NewCost, | |||
4276 | NewRegs, VisitedRegs); | |||
4277 | if (F.getNumRegs() == 1 && Workspace.size() == 1) | |||
4278 | VisitedRegs.insert(F.ScaledReg ? F.ScaledReg : F.BaseRegs[0]); | |||
4279 | } else { | |||
4280 | DEBUG(dbgs() << "New best at "; NewCost.print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "New best at "; NewCost.print (dbgs()); dbgs() << ".\n Regs:"; for (const SCEV *S : NewRegs ) dbgs() << ' ' << *S; dbgs() << '\n'; } } while (0) | |||
4281 | dbgs() << ".\n Regs:";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "New best at "; NewCost.print (dbgs()); dbgs() << ".\n Regs:"; for (const SCEV *S : NewRegs ) dbgs() << ' ' << *S; dbgs() << '\n'; } } while (0) | |||
4282 | for (const SCEV *S : NewRegs)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "New best at "; NewCost.print (dbgs()); dbgs() << ".\n Regs:"; for (const SCEV *S : NewRegs ) dbgs() << ' ' << *S; dbgs() << '\n'; } } while (0) | |||
4283 | dbgs() << ' ' << *S;do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "New best at "; NewCost.print (dbgs()); dbgs() << ".\n Regs:"; for (const SCEV *S : NewRegs ) dbgs() << ' ' << *S; dbgs() << '\n'; } } while (0) | |||
4284 | dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "New best at "; NewCost.print (dbgs()); dbgs() << ".\n Regs:"; for (const SCEV *S : NewRegs ) dbgs() << ' ' << *S; dbgs() << '\n'; } } while (0); | |||
4285 | ||||
4286 | SolutionCost = NewCost; | |||
4287 | Solution = Workspace; | |||
4288 | } | |||
4289 | Workspace.pop_back(); | |||
4290 | } | |||
4291 | } | |||
4292 | } | |||
4293 | ||||
4294 | /// Solve - Choose one formula from each use. Return the results in the given | |||
4295 | /// Solution vector. | |||
4296 | void LSRInstance::Solve(SmallVectorImpl<const Formula *> &Solution) const { | |||
4297 | SmallVector<const Formula *, 8> Workspace; | |||
4298 | Cost SolutionCost; | |||
4299 | SolutionCost.Lose(); | |||
4300 | Cost CurCost; | |||
4301 | SmallPtrSet<const SCEV *, 16> CurRegs; | |||
4302 | DenseSet<const SCEV *> VisitedRegs; | |||
4303 | Workspace.reserve(Uses.size()); | |||
4304 | ||||
4305 | // SolveRecurse does all the work. | |||
4306 | SolveRecurse(Solution, SolutionCost, Workspace, CurCost, | |||
4307 | CurRegs, VisitedRegs); | |||
4308 | if (Solution.empty()) { | |||
4309 | DEBUG(dbgs() << "\nNo Satisfactory Solution\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\nNo Satisfactory Solution\n" ; } } while (0); | |||
4310 | return; | |||
4311 | } | |||
4312 | ||||
4313 | // Ok, we've now made all our decisions. | |||
4314 | DEBUG(dbgs() << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4315 | "The chosen solution requires "; SolutionCost.print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4316 | dbgs() << ":\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4317 | for (size_t i = 0, e = Uses.size(); i != e; ++i) {do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4318 | dbgs() << " ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4319 | Uses[i].print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4320 | dbgs() << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4321 | " ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4322 | Solution[i]->print(dbgs());do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4323 | dbgs() << '\n';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0) | |||
4324 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\n" "The chosen solution requires " ; SolutionCost.print(dbgs()); dbgs() << ":\n"; for (size_t i = 0, e = Uses.size(); i != e; ++i) { dbgs() << " "; Uses[i].print(dbgs()); dbgs() << "\n" " "; Solution [i]->print(dbgs()); dbgs() << '\n'; }; } } while (0); | |||
4325 | ||||
4326 | assert(Solution.size() == Uses.size() && "Malformed solution!")((Solution.size() == Uses.size() && "Malformed solution!" ) ? static_cast<void> (0) : __assert_fail ("Solution.size() == Uses.size() && \"Malformed solution!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4326, __PRETTY_FUNCTION__)); | |||
4327 | } | |||
4328 | ||||
4329 | /// HoistInsertPosition - Helper for AdjustInsertPositionForExpand. Climb up | |||
4330 | /// the dominator tree far as we can go while still being dominated by the | |||
4331 | /// input positions. This helps canonicalize the insert position, which | |||
4332 | /// encourages sharing. | |||
4333 | BasicBlock::iterator | |||
4334 | LSRInstance::HoistInsertPosition(BasicBlock::iterator IP, | |||
4335 | const SmallVectorImpl<Instruction *> &Inputs) | |||
4336 | const { | |||
4337 | for (;;) { | |||
4338 | const Loop *IPLoop = LI.getLoopFor(IP->getParent()); | |||
4339 | unsigned IPLoopDepth = IPLoop ? IPLoop->getLoopDepth() : 0; | |||
4340 | ||||
4341 | BasicBlock *IDom; | |||
4342 | for (DomTreeNode *Rung = DT.getNode(IP->getParent()); ; ) { | |||
4343 | if (!Rung) return IP; | |||
4344 | Rung = Rung->getIDom(); | |||
4345 | if (!Rung) return IP; | |||
4346 | IDom = Rung->getBlock(); | |||
4347 | ||||
4348 | // Don't climb into a loop though. | |||
4349 | const Loop *IDomLoop = LI.getLoopFor(IDom); | |||
4350 | unsigned IDomDepth = IDomLoop ? IDomLoop->getLoopDepth() : 0; | |||
4351 | if (IDomDepth <= IPLoopDepth && | |||
4352 | (IDomDepth != IPLoopDepth || IDomLoop == IPLoop)) | |||
4353 | break; | |||
4354 | } | |||
4355 | ||||
4356 | bool AllDominate = true; | |||
4357 | Instruction *BetterPos = nullptr; | |||
4358 | Instruction *Tentative = IDom->getTerminator(); | |||
4359 | for (Instruction *Inst : Inputs) { | |||
4360 | if (Inst == Tentative || !DT.dominates(Inst, Tentative)) { | |||
4361 | AllDominate = false; | |||
4362 | break; | |||
4363 | } | |||
4364 | // Attempt to find an insert position in the middle of the block, | |||
4365 | // instead of at the end, so that it can be used for other expansions. | |||
4366 | if (IDom == Inst->getParent() && | |||
4367 | (!BetterPos || !DT.dominates(Inst, BetterPos))) | |||
4368 | BetterPos = std::next(BasicBlock::iterator(Inst)); | |||
4369 | } | |||
4370 | if (!AllDominate) | |||
4371 | break; | |||
4372 | if (BetterPos) | |||
4373 | IP = BetterPos; | |||
4374 | else | |||
4375 | IP = Tentative; | |||
4376 | } | |||
4377 | ||||
4378 | return IP; | |||
4379 | } | |||
4380 | ||||
4381 | /// AdjustInsertPositionForExpand - Determine an input position which will be | |||
4382 | /// dominated by the operands and which will dominate the result. | |||
4383 | BasicBlock::iterator | |||
4384 | LSRInstance::AdjustInsertPositionForExpand(BasicBlock::iterator LowestIP, | |||
4385 | const LSRFixup &LF, | |||
4386 | const LSRUse &LU, | |||
4387 | SCEVExpander &Rewriter) const { | |||
4388 | // Collect some instructions which must be dominated by the | |||
4389 | // expanding replacement. These must be dominated by any operands that | |||
4390 | // will be required in the expansion. | |||
4391 | SmallVector<Instruction *, 4> Inputs; | |||
4392 | if (Instruction *I = dyn_cast<Instruction>(LF.OperandValToReplace)) | |||
4393 | Inputs.push_back(I); | |||
4394 | if (LU.Kind == LSRUse::ICmpZero) | |||
4395 | if (Instruction *I = | |||
4396 | dyn_cast<Instruction>(cast<ICmpInst>(LF.UserInst)->getOperand(1))) | |||
4397 | Inputs.push_back(I); | |||
4398 | if (LF.PostIncLoops.count(L)) { | |||
4399 | if (LF.isUseFullyOutsideLoop(L)) | |||
4400 | Inputs.push_back(L->getLoopLatch()->getTerminator()); | |||
4401 | else | |||
4402 | Inputs.push_back(IVIncInsertPos); | |||
4403 | } | |||
4404 | // The expansion must also be dominated by the increment positions of any | |||
4405 | // loops it for which it is using post-inc mode. | |||
4406 | for (const Loop *PIL : LF.PostIncLoops) { | |||
4407 | if (PIL == L) continue; | |||
4408 | ||||
4409 | // Be dominated by the loop exit. | |||
4410 | SmallVector<BasicBlock *, 4> ExitingBlocks; | |||
4411 | PIL->getExitingBlocks(ExitingBlocks); | |||
4412 | if (!ExitingBlocks.empty()) { | |||
4413 | BasicBlock *BB = ExitingBlocks[0]; | |||
4414 | for (unsigned i = 1, e = ExitingBlocks.size(); i != e; ++i) | |||
4415 | BB = DT.findNearestCommonDominator(BB, ExitingBlocks[i]); | |||
4416 | Inputs.push_back(BB->getTerminator()); | |||
4417 | } | |||
4418 | } | |||
4419 | ||||
4420 | assert(!isa<PHINode>(LowestIP) && !isa<LandingPadInst>(LowestIP)((!isa<PHINode>(LowestIP) && !isa<LandingPadInst >(LowestIP) && !isa<DbgInfoIntrinsic>(LowestIP ) && "Insertion point must be a normal instruction") ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(LowestIP) && !isa<LandingPadInst>(LowestIP) && !isa<DbgInfoIntrinsic>(LowestIP) && \"Insertion point must be a normal instruction\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4422, __PRETTY_FUNCTION__)) | |||
4421 | && !isa<DbgInfoIntrinsic>(LowestIP) &&((!isa<PHINode>(LowestIP) && !isa<LandingPadInst >(LowestIP) && !isa<DbgInfoIntrinsic>(LowestIP ) && "Insertion point must be a normal instruction") ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(LowestIP) && !isa<LandingPadInst>(LowestIP) && !isa<DbgInfoIntrinsic>(LowestIP) && \"Insertion point must be a normal instruction\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4422, __PRETTY_FUNCTION__)) | |||
4422 | "Insertion point must be a normal instruction")((!isa<PHINode>(LowestIP) && !isa<LandingPadInst >(LowestIP) && !isa<DbgInfoIntrinsic>(LowestIP ) && "Insertion point must be a normal instruction") ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(LowestIP) && !isa<LandingPadInst>(LowestIP) && !isa<DbgInfoIntrinsic>(LowestIP) && \"Insertion point must be a normal instruction\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4422, __PRETTY_FUNCTION__)); | |||
4423 | ||||
4424 | // Then, climb up the immediate dominator tree as far as we can go while | |||
4425 | // still being dominated by the input positions. | |||
4426 | BasicBlock::iterator IP = HoistInsertPosition(LowestIP, Inputs); | |||
4427 | ||||
4428 | // Don't insert instructions before PHI nodes. | |||
4429 | while (isa<PHINode>(IP)) ++IP; | |||
4430 | ||||
4431 | // Ignore landingpad instructions. | |||
4432 | while (isa<LandingPadInst>(IP)) ++IP; | |||
4433 | ||||
4434 | // Ignore debug intrinsics. | |||
4435 | while (isa<DbgInfoIntrinsic>(IP)) ++IP; | |||
4436 | ||||
4437 | // Set IP below instructions recently inserted by SCEVExpander. This keeps the | |||
4438 | // IP consistent across expansions and allows the previously inserted | |||
4439 | // instructions to be reused by subsequent expansion. | |||
4440 | while (Rewriter.isInsertedInstruction(IP) && IP != LowestIP) ++IP; | |||
4441 | ||||
4442 | return IP; | |||
4443 | } | |||
4444 | ||||
4445 | /// Expand - Emit instructions for the leading candidate expression for this | |||
4446 | /// LSRUse (this is called "expanding"). | |||
4447 | Value *LSRInstance::Expand(const LSRFixup &LF, | |||
4448 | const Formula &F, | |||
4449 | BasicBlock::iterator IP, | |||
4450 | SCEVExpander &Rewriter, | |||
4451 | SmallVectorImpl<WeakVH> &DeadInsts) const { | |||
4452 | const LSRUse &LU = Uses[LF.LUIdx]; | |||
4453 | if (LU.RigidFormula) | |||
4454 | return LF.OperandValToReplace; | |||
4455 | ||||
4456 | // Determine an input position which will be dominated by the operands and | |||
4457 | // which will dominate the result. | |||
4458 | IP = AdjustInsertPositionForExpand(IP, LF, LU, Rewriter); | |||
4459 | ||||
4460 | // Inform the Rewriter if we have a post-increment use, so that it can | |||
4461 | // perform an advantageous expansion. | |||
4462 | Rewriter.setPostInc(LF.PostIncLoops); | |||
4463 | ||||
4464 | // This is the type that the user actually needs. | |||
4465 | Type *OpTy = LF.OperandValToReplace->getType(); | |||
4466 | // This will be the type that we'll initially expand to. | |||
4467 | Type *Ty = F.getType(); | |||
4468 | if (!Ty) | |||
4469 | // No type known; just expand directly to the ultimate type. | |||
4470 | Ty = OpTy; | |||
4471 | else if (SE.getEffectiveSCEVType(Ty) == SE.getEffectiveSCEVType(OpTy)) | |||
4472 | // Expand directly to the ultimate type if it's the right size. | |||
4473 | Ty = OpTy; | |||
4474 | // This is the type to do integer arithmetic in. | |||
4475 | Type *IntTy = SE.getEffectiveSCEVType(Ty); | |||
4476 | ||||
4477 | // Build up a list of operands to add together to form the full base. | |||
4478 | SmallVector<const SCEV *, 8> Ops; | |||
4479 | ||||
4480 | // Expand the BaseRegs portion. | |||
4481 | for (const SCEV *Reg : F.BaseRegs) { | |||
4482 | assert(!Reg->isZero() && "Zero allocated in a base register!")((!Reg->isZero() && "Zero allocated in a base register!" ) ? static_cast<void> (0) : __assert_fail ("!Reg->isZero() && \"Zero allocated in a base register!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4482, __PRETTY_FUNCTION__)); | |||
4483 | ||||
4484 | // If we're expanding for a post-inc user, make the post-inc adjustment. | |||
4485 | PostIncLoopSet &Loops = const_cast<PostIncLoopSet &>(LF.PostIncLoops); | |||
4486 | Reg = TransformForPostIncUse(Denormalize, Reg, | |||
4487 | LF.UserInst, LF.OperandValToReplace, | |||
4488 | Loops, SE, DT); | |||
4489 | ||||
4490 | Ops.push_back(SE.getUnknown(Rewriter.expandCodeFor(Reg, nullptr, IP))); | |||
4491 | } | |||
4492 | ||||
4493 | // Expand the ScaledReg portion. | |||
4494 | Value *ICmpScaledV = nullptr; | |||
4495 | if (F.Scale != 0) { | |||
4496 | const SCEV *ScaledS = F.ScaledReg; | |||
4497 | ||||
4498 | // If we're expanding for a post-inc user, make the post-inc adjustment. | |||
4499 | PostIncLoopSet &Loops = const_cast<PostIncLoopSet &>(LF.PostIncLoops); | |||
4500 | ScaledS = TransformForPostIncUse(Denormalize, ScaledS, | |||
4501 | LF.UserInst, LF.OperandValToReplace, | |||
4502 | Loops, SE, DT); | |||
4503 | ||||
4504 | if (LU.Kind == LSRUse::ICmpZero) { | |||
4505 | // Expand ScaleReg as if it was part of the base regs. | |||
4506 | if (F.Scale == 1) | |||
4507 | Ops.push_back( | |||
4508 | SE.getUnknown(Rewriter.expandCodeFor(ScaledS, nullptr, IP))); | |||
4509 | else { | |||
4510 | // An interesting way of "folding" with an icmp is to use a negated | |||
4511 | // scale, which we'll implement by inserting it into the other operand | |||
4512 | // of the icmp. | |||
4513 | assert(F.Scale == -1 &&((F.Scale == -1 && "The only scale supported by ICmpZero uses is -1!" ) ? static_cast<void> (0) : __assert_fail ("F.Scale == -1 && \"The only scale supported by ICmpZero uses is -1!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4514, __PRETTY_FUNCTION__)) | |||
4514 | "The only scale supported by ICmpZero uses is -1!")((F.Scale == -1 && "The only scale supported by ICmpZero uses is -1!" ) ? static_cast<void> (0) : __assert_fail ("F.Scale == -1 && \"The only scale supported by ICmpZero uses is -1!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4514, __PRETTY_FUNCTION__)); | |||
4515 | ICmpScaledV = Rewriter.expandCodeFor(ScaledS, nullptr, IP); | |||
4516 | } | |||
4517 | } else { | |||
4518 | // Otherwise just expand the scaled register and an explicit scale, | |||
4519 | // which is expected to be matched as part of the address. | |||
4520 | ||||
4521 | // Flush the operand list to suppress SCEVExpander hoisting address modes. | |||
4522 | // Unless the addressing mode will not be folded. | |||
4523 | if (!Ops.empty() && LU.Kind == LSRUse::Address && | |||
4524 | isAMCompletelyFolded(TTI, LU, F)) { | |||
4525 | Value *FullV = Rewriter.expandCodeFor(SE.getAddExpr(Ops), Ty, IP); | |||
4526 | Ops.clear(); | |||
4527 | Ops.push_back(SE.getUnknown(FullV)); | |||
4528 | } | |||
4529 | ScaledS = SE.getUnknown(Rewriter.expandCodeFor(ScaledS, nullptr, IP)); | |||
4530 | if (F.Scale != 1) | |||
4531 | ScaledS = | |||
4532 | SE.getMulExpr(ScaledS, SE.getConstant(ScaledS->getType(), F.Scale)); | |||
4533 | Ops.push_back(ScaledS); | |||
4534 | } | |||
4535 | } | |||
4536 | ||||
4537 | // Expand the GV portion. | |||
4538 | if (F.BaseGV) { | |||
4539 | // Flush the operand list to suppress SCEVExpander hoisting. | |||
4540 | if (!Ops.empty()) { | |||
4541 | Value *FullV = Rewriter.expandCodeFor(SE.getAddExpr(Ops), Ty, IP); | |||
4542 | Ops.clear(); | |||
4543 | Ops.push_back(SE.getUnknown(FullV)); | |||
4544 | } | |||
4545 | Ops.push_back(SE.getUnknown(F.BaseGV)); | |||
4546 | } | |||
4547 | ||||
4548 | // Flush the operand list to suppress SCEVExpander hoisting of both folded and | |||
4549 | // unfolded offsets. LSR assumes they both live next to their uses. | |||
4550 | if (!Ops.empty()) { | |||
4551 | Value *FullV = Rewriter.expandCodeFor(SE.getAddExpr(Ops), Ty, IP); | |||
4552 | Ops.clear(); | |||
4553 | Ops.push_back(SE.getUnknown(FullV)); | |||
4554 | } | |||
4555 | ||||
4556 | // Expand the immediate portion. | |||
4557 | int64_t Offset = (uint64_t)F.BaseOffset + LF.Offset; | |||
4558 | if (Offset != 0) { | |||
4559 | if (LU.Kind == LSRUse::ICmpZero) { | |||
4560 | // The other interesting way of "folding" with an ICmpZero is to use a | |||
4561 | // negated immediate. | |||
4562 | if (!ICmpScaledV) | |||
4563 | ICmpScaledV = ConstantInt::get(IntTy, -(uint64_t)Offset); | |||
4564 | else { | |||
4565 | Ops.push_back(SE.getUnknown(ICmpScaledV)); | |||
4566 | ICmpScaledV = ConstantInt::get(IntTy, Offset); | |||
4567 | } | |||
4568 | } else { | |||
4569 | // Just add the immediate values. These again are expected to be matched | |||
4570 | // as part of the address. | |||
4571 | Ops.push_back(SE.getUnknown(ConstantInt::getSigned(IntTy, Offset))); | |||
4572 | } | |||
4573 | } | |||
4574 | ||||
4575 | // Expand the unfolded offset portion. | |||
4576 | int64_t UnfoldedOffset = F.UnfoldedOffset; | |||
4577 | if (UnfoldedOffset != 0) { | |||
4578 | // Just add the immediate values. | |||
4579 | Ops.push_back(SE.getUnknown(ConstantInt::getSigned(IntTy, | |||
4580 | UnfoldedOffset))); | |||
4581 | } | |||
4582 | ||||
4583 | // Emit instructions summing all the operands. | |||
4584 | const SCEV *FullS = Ops.empty() ? | |||
4585 | SE.getConstant(IntTy, 0) : | |||
4586 | SE.getAddExpr(Ops); | |||
4587 | Value *FullV = Rewriter.expandCodeFor(FullS, Ty, IP); | |||
4588 | ||||
4589 | // We're done expanding now, so reset the rewriter. | |||
4590 | Rewriter.clearPostInc(); | |||
4591 | ||||
4592 | // An ICmpZero Formula represents an ICmp which we're handling as a | |||
4593 | // comparison against zero. Now that we've expanded an expression for that | |||
4594 | // form, update the ICmp's other operand. | |||
4595 | if (LU.Kind == LSRUse::ICmpZero) { | |||
4596 | ICmpInst *CI = cast<ICmpInst>(LF.UserInst); | |||
4597 | DeadInsts.emplace_back(CI->getOperand(1)); | |||
4598 | assert(!F.BaseGV && "ICmp does not support folding a global value and "((!F.BaseGV && "ICmp does not support folding a global value and " "a scale at the same time!") ? static_cast<void> (0) : __assert_fail ("!F.BaseGV && \"ICmp does not support folding a global value and \" \"a scale at the same time!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4599, __PRETTY_FUNCTION__)) | |||
4599 | "a scale at the same time!")((!F.BaseGV && "ICmp does not support folding a global value and " "a scale at the same time!") ? static_cast<void> (0) : __assert_fail ("!F.BaseGV && \"ICmp does not support folding a global value and \" \"a scale at the same time!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4599, __PRETTY_FUNCTION__)); | |||
4600 | if (F.Scale == -1) { | |||
4601 | if (ICmpScaledV->getType() != OpTy) { | |||
4602 | Instruction *Cast = | |||
4603 | CastInst::Create(CastInst::getCastOpcode(ICmpScaledV, false, | |||
4604 | OpTy, false), | |||
4605 | ICmpScaledV, OpTy, "tmp", CI); | |||
4606 | ICmpScaledV = Cast; | |||
4607 | } | |||
4608 | CI->setOperand(1, ICmpScaledV); | |||
4609 | } else { | |||
4610 | // A scale of 1 means that the scale has been expanded as part of the | |||
4611 | // base regs. | |||
4612 | assert((F.Scale == 0 || F.Scale == 1) &&(((F.Scale == 0 || F.Scale == 1) && "ICmp does not support folding a global value and " "a scale at the same time!") ? static_cast<void> (0) : __assert_fail ("(F.Scale == 0 || F.Scale == 1) && \"ICmp does not support folding a global value and \" \"a scale at the same time!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4614, __PRETTY_FUNCTION__)) | |||
4613 | "ICmp does not support folding a global value and "(((F.Scale == 0 || F.Scale == 1) && "ICmp does not support folding a global value and " "a scale at the same time!") ? static_cast<void> (0) : __assert_fail ("(F.Scale == 0 || F.Scale == 1) && \"ICmp does not support folding a global value and \" \"a scale at the same time!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4614, __PRETTY_FUNCTION__)) | |||
4614 | "a scale at the same time!")(((F.Scale == 0 || F.Scale == 1) && "ICmp does not support folding a global value and " "a scale at the same time!") ? static_cast<void> (0) : __assert_fail ("(F.Scale == 0 || F.Scale == 1) && \"ICmp does not support folding a global value and \" \"a scale at the same time!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4614, __PRETTY_FUNCTION__)); | |||
4615 | Constant *C = ConstantInt::getSigned(SE.getEffectiveSCEVType(OpTy), | |||
4616 | -(uint64_t)Offset); | |||
4617 | if (C->getType() != OpTy) | |||
4618 | C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false, | |||
4619 | OpTy, false), | |||
4620 | C, OpTy); | |||
4621 | ||||
4622 | CI->setOperand(1, C); | |||
4623 | } | |||
4624 | } | |||
4625 | ||||
4626 | return FullV; | |||
4627 | } | |||
4628 | ||||
4629 | /// RewriteForPHI - Helper for Rewrite. PHI nodes are special because the use | |||
4630 | /// of their operands effectively happens in their predecessor blocks, so the | |||
4631 | /// expression may need to be expanded in multiple places. | |||
4632 | void LSRInstance::RewriteForPHI(PHINode *PN, | |||
4633 | const LSRFixup &LF, | |||
4634 | const Formula &F, | |||
4635 | SCEVExpander &Rewriter, | |||
4636 | SmallVectorImpl<WeakVH> &DeadInsts, | |||
4637 | Pass *P) const { | |||
4638 | DenseMap<BasicBlock *, Value *> Inserted; | |||
4639 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) | |||
| ||||
4640 | if (PN->getIncomingValue(i) == LF.OperandValToReplace) { | |||
4641 | BasicBlock *BB = PN->getIncomingBlock(i); | |||
4642 | ||||
4643 | // If this is a critical edge, split the edge so that we do not insert | |||
4644 | // the code on all predecessor/successor paths. We do this unless this | |||
4645 | // is the canonical backedge for this loop, which complicates post-inc | |||
4646 | // users. | |||
4647 | if (e != 1 && BB->getTerminator()->getNumSuccessors() > 1 && | |||
4648 | !isa<IndirectBrInst>(BB->getTerminator())) { | |||
4649 | BasicBlock *Parent = PN->getParent(); | |||
4650 | Loop *PNLoop = LI.getLoopFor(Parent); | |||
4651 | if (!PNLoop || Parent != PNLoop->getHeader()) { | |||
4652 | // Split the critical edge. | |||
4653 | BasicBlock *NewBB = nullptr; | |||
4654 | if (!Parent->isLandingPad()) { | |||
4655 | NewBB = SplitCriticalEdge(BB, Parent, | |||
4656 | CriticalEdgeSplittingOptions(&DT, &LI) | |||
4657 | .setMergeIdenticalEdges() | |||
4658 | .setDontDeleteUselessPHIs()); | |||
4659 | } else { | |||
4660 | SmallVector<BasicBlock*, 2> NewBBs; | |||
4661 | SplitLandingPadPredecessors(Parent, BB, "", "", NewBBs, | |||
4662 | /*AliasAnalysis*/ nullptr, &DT, &LI); | |||
4663 | NewBB = NewBBs[0]; | |||
4664 | } | |||
4665 | // If NewBB==NULL, then SplitCriticalEdge refused to split because all | |||
4666 | // phi predecessors are identical. The simple thing to do is skip | |||
4667 | // splitting in this case rather than complicate the API. | |||
4668 | if (NewBB) { | |||
4669 | // If PN is outside of the loop and BB is in the loop, we want to | |||
4670 | // move the block to be immediately before the PHI block, not | |||
4671 | // immediately after BB. | |||
4672 | if (L->contains(BB) && !L->contains(PN)) | |||
4673 | NewBB->moveBefore(PN->getParent()); | |||
4674 | ||||
4675 | // Splitting the edge can reduce the number of PHI entries we have. | |||
4676 | e = PN->getNumIncomingValues(); | |||
4677 | BB = NewBB; | |||
4678 | i = PN->getBasicBlockIndex(BB); | |||
4679 | } | |||
4680 | } | |||
4681 | } | |||
4682 | ||||
4683 | std::pair<DenseMap<BasicBlock *, Value *>::iterator, bool> Pair = | |||
4684 | Inserted.insert(std::make_pair(BB, static_cast<Value *>(nullptr))); | |||
4685 | if (!Pair.second) | |||
4686 | PN->setIncomingValue(i, Pair.first->second); | |||
4687 | else { | |||
4688 | Value *FullV = Expand(LF, F, BB->getTerminator(), Rewriter, DeadInsts); | |||
4689 | ||||
4690 | // If this is reuse-by-noop-cast, insert the noop cast. | |||
4691 | Type *OpTy = LF.OperandValToReplace->getType(); | |||
| ||||
4692 | if (FullV->getType() != OpTy) | |||
4693 | FullV = | |||
4694 | CastInst::Create(CastInst::getCastOpcode(FullV, false, | |||
4695 | OpTy, false), | |||
4696 | FullV, LF.OperandValToReplace->getType(), | |||
4697 | "tmp", BB->getTerminator()); | |||
4698 | ||||
4699 | PN->setIncomingValue(i, FullV); | |||
4700 | Pair.first->second = FullV; | |||
4701 | } | |||
4702 | } | |||
4703 | } | |||
4704 | ||||
4705 | /// Rewrite - Emit instructions for the leading candidate expression for this | |||
4706 | /// LSRUse (this is called "expanding"), and update the UserInst to reference | |||
4707 | /// the newly expanded value. | |||
4708 | void LSRInstance::Rewrite(const LSRFixup &LF, | |||
4709 | const Formula &F, | |||
4710 | SCEVExpander &Rewriter, | |||
4711 | SmallVectorImpl<WeakVH> &DeadInsts, | |||
4712 | Pass *P) const { | |||
4713 | // First, find an insertion point that dominates UserInst. For PHI nodes, | |||
4714 | // find the nearest block which dominates all the relevant uses. | |||
4715 | if (PHINode *PN = dyn_cast<PHINode>(LF.UserInst)) { | |||
4716 | RewriteForPHI(PN, LF, F, Rewriter, DeadInsts, P); | |||
4717 | } else { | |||
4718 | Value *FullV = Expand(LF, F, LF.UserInst, Rewriter, DeadInsts); | |||
4719 | ||||
4720 | // If this is reuse-by-noop-cast, insert the noop cast. | |||
4721 | Type *OpTy = LF.OperandValToReplace->getType(); | |||
4722 | if (FullV->getType() != OpTy) { | |||
4723 | Instruction *Cast = | |||
4724 | CastInst::Create(CastInst::getCastOpcode(FullV, false, OpTy, false), | |||
4725 | FullV, OpTy, "tmp", LF.UserInst); | |||
4726 | FullV = Cast; | |||
4727 | } | |||
4728 | ||||
4729 | // Update the user. ICmpZero is handled specially here (for now) because | |||
4730 | // Expand may have updated one of the operands of the icmp already, and | |||
4731 | // its new value may happen to be equal to LF.OperandValToReplace, in | |||
4732 | // which case doing replaceUsesOfWith leads to replacing both operands | |||
4733 | // with the same value. TODO: Reorganize this. | |||
4734 | if (Uses[LF.LUIdx].Kind == LSRUse::ICmpZero) | |||
4735 | LF.UserInst->setOperand(0, FullV); | |||
4736 | else | |||
4737 | LF.UserInst->replaceUsesOfWith(LF.OperandValToReplace, FullV); | |||
4738 | } | |||
4739 | ||||
4740 | DeadInsts.emplace_back(LF.OperandValToReplace); | |||
4741 | } | |||
4742 | ||||
4743 | /// ImplementSolution - Rewrite all the fixup locations with new values, | |||
4744 | /// following the chosen solution. | |||
4745 | void | |||
4746 | LSRInstance::ImplementSolution(const SmallVectorImpl<const Formula *> &Solution, | |||
4747 | Pass *P) { | |||
4748 | // Keep track of instructions we may have made dead, so that | |||
4749 | // we can remove them after we are done working. | |||
4750 | SmallVector<WeakVH, 16> DeadInsts; | |||
4751 | ||||
4752 | SCEVExpander Rewriter(SE, L->getHeader()->getModule()->getDataLayout(), | |||
4753 | "lsr"); | |||
4754 | #ifndef NDEBUG | |||
4755 | Rewriter.setDebugType(DEBUG_TYPE"loop-reduce"); | |||
4756 | #endif | |||
4757 | Rewriter.disableCanonicalMode(); | |||
4758 | Rewriter.enableLSRMode(); | |||
4759 | Rewriter.setIVIncInsertPos(L, IVIncInsertPos); | |||
4760 | ||||
4761 | // Mark phi nodes that terminate chains so the expander tries to reuse them. | |||
4762 | for (const IVChain &Chain : IVChainVec) { | |||
4763 | if (PHINode *PN = dyn_cast<PHINode>(Chain.tailUserInst())) | |||
4764 | Rewriter.setChainedPhi(PN); | |||
4765 | } | |||
4766 | ||||
4767 | // Expand the new value definitions and update the users. | |||
4768 | for (const LSRFixup &Fixup : Fixups) { | |||
4769 | Rewrite(Fixup, *Solution[Fixup.LUIdx], Rewriter, DeadInsts, P); | |||
4770 | ||||
4771 | Changed = true; | |||
4772 | } | |||
4773 | ||||
4774 | for (const IVChain &Chain : IVChainVec) { | |||
4775 | GenerateIVChain(Chain, Rewriter, DeadInsts); | |||
4776 | Changed = true; | |||
4777 | } | |||
4778 | // Clean up after ourselves. This must be done before deleting any | |||
4779 | // instructions. | |||
4780 | Rewriter.clear(); | |||
4781 | ||||
4782 | Changed |= DeleteTriviallyDeadInstructions(DeadInsts); | |||
4783 | } | |||
4784 | ||||
4785 | LSRInstance::LSRInstance(Loop *L, Pass *P) | |||
4786 | : IU(P->getAnalysis<IVUsers>()), SE(P->getAnalysis<ScalarEvolution>()), | |||
4787 | DT(P->getAnalysis<DominatorTreeWrapperPass>().getDomTree()), | |||
4788 | LI(P->getAnalysis<LoopInfoWrapperPass>().getLoopInfo()), | |||
4789 | TTI(P->getAnalysis<TargetTransformInfoWrapperPass>().getTTI( | |||
4790 | *L->getHeader()->getParent())), | |||
4791 | L(L), Changed(false), IVIncInsertPos(nullptr) { | |||
4792 | // If LoopSimplify form is not available, stay out of trouble. | |||
4793 | if (!L->isLoopSimplifyForm()) | |||
4794 | return; | |||
4795 | ||||
4796 | // If there's no interesting work to be done, bail early. | |||
4797 | if (IU.empty()) return; | |||
4798 | ||||
4799 | // If there's too much analysis to be done, bail early. We won't be able to | |||
4800 | // model the problem anyway. | |||
4801 | unsigned NumUsers = 0; | |||
4802 | for (const IVStrideUse &U : IU) { | |||
4803 | if (++NumUsers > MaxIVUsers) { | |||
4804 | (void)U; | |||
4805 | DEBUG(dbgs() << "LSR skipping loop, too many IV Users in " << U << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "LSR skipping loop, too many IV Users in " << U << "\n"; } } while (0); | |||
4806 | return; | |||
4807 | } | |||
4808 | } | |||
4809 | ||||
4810 | #ifndef NDEBUG | |||
4811 | // All dominating loops must have preheaders, or SCEVExpander may not be able | |||
4812 | // to materialize an AddRecExpr whose Start is an outer AddRecExpr. | |||
4813 | // | |||
4814 | // IVUsers analysis should only create users that are dominated by simple loop | |||
4815 | // headers. Since this loop should dominate all of its users, its user list | |||
4816 | // should be empty if this loop itself is not within a simple loop nest. | |||
4817 | for (DomTreeNode *Rung = DT.getNode(L->getLoopPreheader()); | |||
4818 | Rung; Rung = Rung->getIDom()) { | |||
4819 | BasicBlock *BB = Rung->getBlock(); | |||
4820 | const Loop *DomLoop = LI.getLoopFor(BB); | |||
4821 | if (DomLoop && DomLoop->getHeader() == BB) { | |||
4822 | assert(DomLoop->getLoopPreheader() && "LSR needs a simplified loop nest")((DomLoop->getLoopPreheader() && "LSR needs a simplified loop nest" ) ? static_cast<void> (0) : __assert_fail ("DomLoop->getLoopPreheader() && \"LSR needs a simplified loop nest\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4822, __PRETTY_FUNCTION__)); | |||
4823 | } | |||
4824 | } | |||
4825 | #endif // DEBUG | |||
4826 | ||||
4827 | DEBUG(dbgs() << "\nLSR on loop ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\nLSR on loop "; L->getHeader ()->printAsOperand(dbgs(), false); dbgs() << ":\n"; } } while (0) | |||
4828 | L->getHeader()->printAsOperand(dbgs(), /*PrintType=*/false);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\nLSR on loop "; L->getHeader ()->printAsOperand(dbgs(), false); dbgs() << ":\n"; } } while (0) | |||
4829 | dbgs() << ":\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "\nLSR on loop "; L->getHeader ()->printAsOperand(dbgs(), false); dbgs() << ":\n"; } } while (0); | |||
4830 | ||||
4831 | // First, perform some low-level loop optimizations. | |||
4832 | OptimizeShadowIV(); | |||
4833 | OptimizeLoopTermCond(); | |||
4834 | ||||
4835 | // If loop preparation eliminates all interesting IV users, bail. | |||
4836 | if (IU.empty()) return; | |||
4837 | ||||
4838 | // Skip nested loops until we can model them better with formulae. | |||
4839 | if (!L->empty()) { | |||
4840 | DEBUG(dbgs() << "LSR skipping outer loop " << *L << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "LSR skipping outer loop " << *L << "\n"; } } while (0); | |||
4841 | return; | |||
4842 | } | |||
4843 | ||||
4844 | // Start collecting data and preparing for the solver. | |||
4845 | CollectChains(); | |||
4846 | CollectInterestingTypesAndFactors(); | |||
4847 | CollectFixupsAndInitialFormulae(); | |||
4848 | CollectLoopInvariantFixupsAndFormulae(); | |||
4849 | ||||
4850 | assert(!Uses.empty() && "IVUsers reported at least one use")((!Uses.empty() && "IVUsers reported at least one use" ) ? static_cast<void> (0) : __assert_fail ("!Uses.empty() && \"IVUsers reported at least one use\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4850, __PRETTY_FUNCTION__)); | |||
4851 | DEBUG(dbgs() << "LSR found " << Uses.size() << " uses:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "LSR found " << Uses .size() << " uses:\n"; print_uses(dbgs()); } } while (0 ) | |||
4852 | print_uses(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("loop-reduce")) { dbgs() << "LSR found " << Uses .size() << " uses:\n"; print_uses(dbgs()); } } while (0 ); | |||
4853 | ||||
4854 | // Now use the reuse data to generate a bunch of interesting ways | |||
4855 | // to formulate the values needed for the uses. | |||
4856 | GenerateAllReuseFormulae(); | |||
4857 | ||||
4858 | FilterOutUndesirableDedicatedRegisters(); | |||
4859 | NarrowSearchSpaceUsingHeuristics(); | |||
4860 | ||||
4861 | SmallVector<const Formula *, 8> Solution; | |||
4862 | Solve(Solution); | |||
4863 | ||||
4864 | // Release memory that is no longer needed. | |||
4865 | Factors.clear(); | |||
4866 | Types.clear(); | |||
4867 | RegUses.clear(); | |||
4868 | ||||
4869 | if (Solution.empty()) | |||
4870 | return; | |||
4871 | ||||
4872 | #ifndef NDEBUG | |||
4873 | // Formulae should be legal. | |||
4874 | for (const LSRUse &LU : Uses) { | |||
4875 | for (const Formula &F : LU.Formulae) | |||
4876 | assert(isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy,((isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy , F) && "Illegal formula generated!") ? static_cast< void> (0) : __assert_fail ("isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, F) && \"Illegal formula generated!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4877, __PRETTY_FUNCTION__)) | |||
4877 | F) && "Illegal formula generated!")((isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy , F) && "Illegal formula generated!") ? static_cast< void> (0) : __assert_fail ("isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy, F) && \"Illegal formula generated!\"" , "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4877, __PRETTY_FUNCTION__)); | |||
4878 | }; | |||
4879 | #endif | |||
4880 | ||||
4881 | // Now that we've decided what we want, make it so. | |||
4882 | ImplementSolution(Solution, P); | |||
4883 | } | |||
4884 | ||||
4885 | void LSRInstance::print_factors_and_types(raw_ostream &OS) const { | |||
4886 | if (Factors.empty() && Types.empty()) return; | |||
4887 | ||||
4888 | OS << "LSR has identified the following interesting factors and types: "; | |||
4889 | bool First = true; | |||
4890 | ||||
4891 | for (int64_t Factor : Factors) { | |||
4892 | if (!First) OS << ", "; | |||
4893 | First = false; | |||
4894 | OS << '*' << Factor; | |||
4895 | } | |||
4896 | ||||
4897 | for (Type *Ty : Types) { | |||
4898 | if (!First) OS << ", "; | |||
4899 | First = false; | |||
4900 | OS << '(' << *Ty << ')'; | |||
4901 | } | |||
4902 | OS << '\n'; | |||
4903 | } | |||
4904 | ||||
4905 | void LSRInstance::print_fixups(raw_ostream &OS) const { | |||
4906 | OS << "LSR is examining the following fixup sites:\n"; | |||
4907 | for (const LSRFixup &LF : Fixups) { | |||
4908 | dbgs() << " "; | |||
4909 | LF.print(OS); | |||
4910 | OS << '\n'; | |||
4911 | } | |||
4912 | } | |||
4913 | ||||
4914 | void LSRInstance::print_uses(raw_ostream &OS) const { | |||
4915 | OS << "LSR is examining the following uses:\n"; | |||
4916 | for (const LSRUse &LU : Uses) { | |||
4917 | dbgs() << " "; | |||
4918 | LU.print(OS); | |||
4919 | OS << '\n'; | |||
4920 | for (const Formula &F : LU.Formulae) { | |||
4921 | OS << " "; | |||
4922 | F.print(OS); | |||
4923 | OS << '\n'; | |||
4924 | } | |||
4925 | } | |||
4926 | } | |||
4927 | ||||
4928 | void LSRInstance::print(raw_ostream &OS) const { | |||
4929 | print_factors_and_types(OS); | |||
4930 | print_fixups(OS); | |||
4931 | print_uses(OS); | |||
4932 | } | |||
4933 | ||||
4934 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | |||
4935 | void LSRInstance::dump() const { | |||
4936 | print(errs()); errs() << '\n'; | |||
4937 | } | |||
4938 | #endif | |||
4939 | ||||
4940 | namespace { | |||
4941 | ||||
4942 | class LoopStrengthReduce : public LoopPass { | |||
4943 | public: | |||
4944 | static char ID; // Pass ID, replacement for typeid | |||
4945 | LoopStrengthReduce(); | |||
4946 | ||||
4947 | private: | |||
4948 | bool runOnLoop(Loop *L, LPPassManager &LPM) override; | |||
4949 | void getAnalysisUsage(AnalysisUsage &AU) const override; | |||
4950 | }; | |||
4951 | ||||
4952 | } | |||
4953 | ||||
4954 | char LoopStrengthReduce::ID = 0; | |||
4955 | INITIALIZE_PASS_BEGIN(LoopStrengthReduce, "loop-reduce",static void* initializeLoopStrengthReducePassOnce(PassRegistry &Registry) { | |||
4956 | "Loop Strength Reduction", false, false)static void* initializeLoopStrengthReducePassOnce(PassRegistry &Registry) { | |||
4957 | INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry); | |||
4958 | INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry); | |||
4959 | INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)initializeScalarEvolutionPass(Registry); | |||
4960 | INITIALIZE_PASS_DEPENDENCY(IVUsers)initializeIVUsersPass(Registry); | |||
4961 | INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)initializeLoopInfoWrapperPassPass(Registry); | |||
4962 | INITIALIZE_PASS_DEPENDENCY(LoopSimplify)initializeLoopSimplifyPass(Registry); | |||
4963 | INITIALIZE_PASS_END(LoopStrengthReduce, "loop-reduce",PassInfo *PI = new PassInfo("Loop Strength Reduction", "loop-reduce" , & LoopStrengthReduce ::ID, PassInfo::NormalCtor_t(callDefaultCtor < LoopStrengthReduce >), false, false); Registry.registerPass (*PI, true); return PI; } void llvm::initializeLoopStrengthReducePass (PassRegistry &Registry) { static volatile sys::cas_flag initialized = 0; sys::cas_flag old_val = sys::CompareAndSwap(&initialized , 1, 0); if (old_val == 0) { initializeLoopStrengthReducePassOnce (Registry); sys::MemoryFence(); AnnotateIgnoreWritesBegin("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964); AnnotateHappensBefore("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964, &initialized); initialized = 2; AnnotateIgnoreWritesEnd ("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964); } else { sys::cas_flag tmp = initialized; sys::MemoryFence (); while (tmp != 2) { tmp = initialized; sys::MemoryFence(); } } AnnotateHappensAfter("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964, &initialized); } | |||
4964 | "Loop Strength Reduction", false, false)PassInfo *PI = new PassInfo("Loop Strength Reduction", "loop-reduce" , & LoopStrengthReduce ::ID, PassInfo::NormalCtor_t(callDefaultCtor < LoopStrengthReduce >), false, false); Registry.registerPass (*PI, true); return PI; } void llvm::initializeLoopStrengthReducePass (PassRegistry &Registry) { static volatile sys::cas_flag initialized = 0; sys::cas_flag old_val = sys::CompareAndSwap(&initialized , 1, 0); if (old_val == 0) { initializeLoopStrengthReducePassOnce (Registry); sys::MemoryFence(); AnnotateIgnoreWritesBegin("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964); AnnotateHappensBefore("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964, &initialized); initialized = 2; AnnotateIgnoreWritesEnd ("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964); } else { sys::cas_flag tmp = initialized; sys::MemoryFence (); while (tmp != 2) { tmp = initialized; sys::MemoryFence(); } } AnnotateHappensAfter("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn239598/lib/Transforms/Scalar/LoopStrengthReduce.cpp" , 4964, &initialized); } | |||
4965 | ||||
4966 | ||||
4967 | Pass *llvm::createLoopStrengthReducePass() { | |||
4968 | return new LoopStrengthReduce(); | |||
4969 | } | |||
4970 | ||||
4971 | LoopStrengthReduce::LoopStrengthReduce() : LoopPass(ID) { | |||
4972 | initializeLoopStrengthReducePass(*PassRegistry::getPassRegistry()); | |||
4973 | } | |||
4974 | ||||
4975 | void LoopStrengthReduce::getAnalysisUsage(AnalysisUsage &AU) const { | |||
4976 | // We split critical edges, so we change the CFG. However, we do update | |||
4977 | // many analyses if they are around. | |||
4978 | AU.addPreservedID(LoopSimplifyID); | |||
4979 | ||||
4980 | AU.addRequired<LoopInfoWrapperPass>(); | |||
4981 | AU.addPreserved<LoopInfoWrapperPass>(); | |||
4982 | AU.addRequiredID(LoopSimplifyID); | |||
4983 | AU.addRequired<DominatorTreeWrapperPass>(); | |||
4984 | AU.addPreserved<DominatorTreeWrapperPass>(); | |||
4985 | AU.addRequired<ScalarEvolution>(); | |||
4986 | AU.addPreserved<ScalarEvolution>(); | |||
4987 | // Requiring LoopSimplify a second time here prevents IVUsers from running | |||
4988 | // twice, since LoopSimplify was invalidated by running ScalarEvolution. | |||
4989 | AU.addRequiredID(LoopSimplifyID); | |||
4990 | AU.addRequired<IVUsers>(); | |||
4991 | AU.addPreserved<IVUsers>(); | |||
4992 | AU.addRequired<TargetTransformInfoWrapperPass>(); | |||
4993 | } | |||
4994 | ||||
4995 | bool LoopStrengthReduce::runOnLoop(Loop *L, LPPassManager & /*LPM*/) { | |||
4996 | if (skipOptnoneFunction(L)) | |||
4997 | return false; | |||
4998 | ||||
4999 | bool Changed = false; | |||
5000 | ||||
5001 | // Run the main LSR transformation. | |||
5002 | Changed |= LSRInstance(L, this).getChanged(); | |||
5003 | ||||
5004 | // Remove any extra phis created by processing inner loops. | |||
5005 | Changed |= DeleteDeadPHIs(L->getHeader()); | |||
5006 | if (EnablePhiElim && L->isLoopSimplifyForm()) { | |||
5007 | SmallVector<WeakVH, 16> DeadInsts; | |||
5008 | const DataLayout &DL = L->getHeader()->getModule()->getDataLayout(); | |||
5009 | SCEVExpander Rewriter(getAnalysis<ScalarEvolution>(), DL, "lsr"); | |||
5010 | #ifndef NDEBUG | |||
5011 | Rewriter.setDebugType(DEBUG_TYPE"loop-reduce"); | |||
5012 | #endif | |||
5013 | unsigned numFolded = Rewriter.replaceCongruentIVs( | |||
5014 | L, &getAnalysis<DominatorTreeWrapperPass>().getDomTree(), DeadInsts, | |||
5015 | &getAnalysis<TargetTransformInfoWrapperPass>().getTTI( | |||
5016 | *L->getHeader()->getParent())); | |||
5017 | if (numFolded) { | |||
5018 | Changed = true; | |||
5019 | DeleteTriviallyDeadInstructions(DeadInsts); | |||
5020 | DeleteDeadPHIs(L->getHeader()); | |||
5021 | } | |||
5022 | } | |||
5023 | return Changed; | |||
5024 | } |