1 //===- InterleavedLoadCombine.cpp - Combine Interleaved Loads ---*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // \file
10 //
11 // This file defines the interleaved-load-combine pass. The pass searches for
12 // ShuffleVectorInstruction that execute interleaving loads. If a matching
13 // pattern is found, it adds a combined load and further instructions in a
14 // pattern that is detectable by InterleavedAccesPass. The old instructions are
15 // left dead to be removed later. The pass is specifically designed to be
16 // executed just before InterleavedAccesPass to find any left-over instances
17 // that are not detected within former passes.
18 //
19 //===----------------------------------------------------------------------===//
20
21 #include "llvm/ADT/Statistic.h"
22 #include "llvm/Analysis/MemoryLocation.h"
23 #include "llvm/Analysis/MemorySSA.h"
24 #include "llvm/Analysis/MemorySSAUpdater.h"
25 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
26 #include "llvm/Analysis/TargetTransformInfo.h"
27 #include "llvm/CodeGen/Passes.h"
28 #include "llvm/CodeGen/TargetLowering.h"
29 #include "llvm/CodeGen/TargetPassConfig.h"
30 #include "llvm/CodeGen/TargetSubtargetInfo.h"
31 #include "llvm/IR/DataLayout.h"
32 #include "llvm/IR/Dominators.h"
33 #include "llvm/IR/Function.h"
34 #include "llvm/IR/Instructions.h"
35 #include "llvm/IR/LegacyPassManager.h"
36 #include "llvm/IR/Module.h"
37 #include "llvm/InitializePasses.h"
38 #include "llvm/Pass.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/ErrorHandling.h"
41 #include "llvm/Support/raw_ostream.h"
42 #include "llvm/Target/TargetMachine.h"
43
44 #include <algorithm>
45 #include <cassert>
46 #include <list>
47
48 using namespace llvm;
49
50 #define DEBUG_TYPE "interleaved-load-combine"
51
52 namespace {
53
54 /// Statistic counter
55 STATISTIC(NumInterleavedLoadCombine, "Number of combined loads");
56
57 /// Option to disable the pass
58 static cl::opt<bool> DisableInterleavedLoadCombine(
59 "disable-" DEBUG_TYPE, cl::init(false), cl::Hidden,
60 cl::desc("Disable combining of interleaved loads"));
61
62 struct VectorInfo;
63
64 struct InterleavedLoadCombineImpl {
65 public:
InterleavedLoadCombineImpl__anon3482201f0111::InterleavedLoadCombineImpl66 InterleavedLoadCombineImpl(Function &F, DominatorTree &DT, MemorySSA &MSSA,
67 TargetMachine &TM)
68 : F(F), DT(DT), MSSA(MSSA),
69 TLI(*TM.getSubtargetImpl(F)->getTargetLowering()),
70 TTI(TM.getTargetTransformInfo(F)) {}
71
72 /// Scan the function for interleaved load candidates and execute the
73 /// replacement if applicable.
74 bool run();
75
76 private:
77 /// Function this pass is working on
78 Function &F;
79
80 /// Dominator Tree Analysis
81 DominatorTree &DT;
82
83 /// Memory Alias Analyses
84 MemorySSA &MSSA;
85
86 /// Target Lowering Information
87 const TargetLowering &TLI;
88
89 /// Target Transform Information
90 const TargetTransformInfo TTI;
91
92 /// Find the instruction in sets LIs that dominates all others, return nullptr
93 /// if there is none.
94 LoadInst *findFirstLoad(const std::set<LoadInst *> &LIs);
95
96 /// Replace interleaved load candidates. It does additional
97 /// analyses if this makes sense. Returns true on success and false
98 /// of nothing has been changed.
99 bool combine(std::list<VectorInfo> &InterleavedLoad,
100 OptimizationRemarkEmitter &ORE);
101
102 /// Given a set of VectorInfo containing candidates for a given interleave
103 /// factor, find a set that represents a 'factor' interleaved load.
104 bool findPattern(std::list<VectorInfo> &Candidates,
105 std::list<VectorInfo> &InterleavedLoad, unsigned Factor,
106 const DataLayout &DL);
107 }; // InterleavedLoadCombine
108
109 /// First Order Polynomial on an n-Bit Integer Value
110 ///
111 /// Polynomial(Value) = Value * B + A + E*2^(n-e)
112 ///
113 /// A and B are the coefficients. E*2^(n-e) is an error within 'e' most
114 /// significant bits. It is introduced if an exact computation cannot be proven
115 /// (e.q. division by 2).
116 ///
117 /// As part of this optimization multiple loads will be combined. It necessary
118 /// to prove that loads are within some relative offset to each other. This
119 /// class is used to prove relative offsets of values loaded from memory.
120 ///
121 /// Representing an integer in this form is sound since addition in two's
122 /// complement is associative (trivial) and multiplication distributes over the
123 /// addition (see Proof(1) in Polynomial::mul). Further, both operations
124 /// commute.
125 //
126 // Example:
127 // declare @fn(i64 %IDX, <4 x float>* %PTR) {
128 // %Pa1 = add i64 %IDX, 2
129 // %Pa2 = lshr i64 %Pa1, 1
130 // %Pa3 = getelementptr inbounds <4 x float>, <4 x float>* %PTR, i64 %Pa2
131 // %Va = load <4 x float>, <4 x float>* %Pa3
132 //
133 // %Pb1 = add i64 %IDX, 4
134 // %Pb2 = lshr i64 %Pb1, 1
135 // %Pb3 = getelementptr inbounds <4 x float>, <4 x float>* %PTR, i64 %Pb2
136 // %Vb = load <4 x float>, <4 x float>* %Pb3
137 // ... }
138 //
139 // The goal is to prove that two loads load consecutive addresses.
140 //
141 // In this case the polynomials are constructed by the following
142 // steps.
143 //
144 // The number tag #e specifies the error bits.
145 //
146 // Pa_0 = %IDX #0
147 // Pa_1 = %IDX + 2 #0 | add 2
148 // Pa_2 = %IDX/2 + 1 #1 | lshr 1
149 // Pa_3 = %IDX/2 + 1 #1 | GEP, step signext to i64
150 // Pa_4 = (%IDX/2)*16 + 16 #0 | GEP, multiply index by sizeof(4) for floats
151 // Pa_5 = (%IDX/2)*16 + 16 #0 | GEP, add offset of leading components
152 //
153 // Pb_0 = %IDX #0
154 // Pb_1 = %IDX + 4 #0 | add 2
155 // Pb_2 = %IDX/2 + 2 #1 | lshr 1
156 // Pb_3 = %IDX/2 + 2 #1 | GEP, step signext to i64
157 // Pb_4 = (%IDX/2)*16 + 32 #0 | GEP, multiply index by sizeof(4) for floats
158 // Pb_5 = (%IDX/2)*16 + 16 #0 | GEP, add offset of leading components
159 //
160 // Pb_5 - Pa_5 = 16 #0 | subtract to get the offset
161 //
162 // Remark: %PTR is not maintained within this class. So in this instance the
163 // offset of 16 can only be assumed if the pointers are equal.
164 //
165 class Polynomial {
166 /// Operations on B
167 enum BOps {
168 LShr,
169 Mul,
170 SExt,
171 Trunc,
172 };
173
174 /// Number of Error Bits e
175 unsigned ErrorMSBs;
176
177 /// Value
178 Value *V;
179
180 /// Coefficient B
181 SmallVector<std::pair<BOps, APInt>, 4> B;
182
183 /// Coefficient A
184 APInt A;
185
186 public:
Polynomial(Value * V)187 Polynomial(Value *V) : ErrorMSBs((unsigned)-1), V(V), B(), A() {
188 IntegerType *Ty = dyn_cast<IntegerType>(V->getType());
189 if (Ty) {
190 ErrorMSBs = 0;
191 this->V = V;
192 A = APInt(Ty->getBitWidth(), 0);
193 }
194 }
195
Polynomial(const APInt & A,unsigned ErrorMSBs=0)196 Polynomial(const APInt &A, unsigned ErrorMSBs = 0)
197 : ErrorMSBs(ErrorMSBs), V(NULL), B(), A(A) {}
198
Polynomial(unsigned BitWidth,uint64_t A,unsigned ErrorMSBs=0)199 Polynomial(unsigned BitWidth, uint64_t A, unsigned ErrorMSBs = 0)
200 : ErrorMSBs(ErrorMSBs), V(NULL), B(), A(BitWidth, A) {}
201
Polynomial()202 Polynomial() : ErrorMSBs((unsigned)-1), V(NULL), B(), A() {}
203
204 /// Increment and clamp the number of undefined bits.
incErrorMSBs(unsigned amt)205 void incErrorMSBs(unsigned amt) {
206 if (ErrorMSBs == (unsigned)-1)
207 return;
208
209 ErrorMSBs += amt;
210 if (ErrorMSBs > A.getBitWidth())
211 ErrorMSBs = A.getBitWidth();
212 }
213
214 /// Decrement and clamp the number of undefined bits.
decErrorMSBs(unsigned amt)215 void decErrorMSBs(unsigned amt) {
216 if (ErrorMSBs == (unsigned)-1)
217 return;
218
219 if (ErrorMSBs > amt)
220 ErrorMSBs -= amt;
221 else
222 ErrorMSBs = 0;
223 }
224
225 /// Apply an add on the polynomial
add(const APInt & C)226 Polynomial &add(const APInt &C) {
227 // Note: Addition is associative in two's complement even when in case of
228 // signed overflow.
229 //
230 // Error bits can only propagate into higher significant bits. As these are
231 // already regarded as undefined, there is no change.
232 //
233 // Theorem: Adding a constant to a polynomial does not change the error
234 // term.
235 //
236 // Proof:
237 //
238 // Since the addition is associative and commutes:
239 //
240 // (B + A + E*2^(n-e)) + C = B + (A + C) + E*2^(n-e)
241 // [qed]
242
243 if (C.getBitWidth() != A.getBitWidth()) {
244 ErrorMSBs = (unsigned)-1;
245 return *this;
246 }
247
248 A += C;
249 return *this;
250 }
251
252 /// Apply a multiplication onto the polynomial.
mul(const APInt & C)253 Polynomial &mul(const APInt &C) {
254 // Note: Multiplication distributes over the addition
255 //
256 // Theorem: Multiplication distributes over the addition
257 //
258 // Proof(1):
259 //
260 // (B+A)*C =-
261 // = (B + A) + (B + A) + .. {C Times}
262 // addition is associative and commutes, hence
263 // = B + B + .. {C Times} .. + A + A + .. {C times}
264 // = B*C + A*C
265 // (see (function add) for signed values and overflows)
266 // [qed]
267 //
268 // Theorem: If C has c trailing zeros, errors bits in A or B are shifted out
269 // to the left.
270 //
271 // Proof(2):
272 //
273 // Let B' and A' be the n-Bit inputs with some unknown errors EA,
274 // EB at e leading bits. B' and A' can be written down as:
275 //
276 // B' = B + 2^(n-e)*EB
277 // A' = A + 2^(n-e)*EA
278 //
279 // Let C' be an input with c trailing zero bits. C' can be written as
280 //
281 // C' = C*2^c
282 //
283 // Therefore we can compute the result by using distributivity and
284 // commutativity.
285 //
286 // (B'*C' + A'*C') = [B + 2^(n-e)*EB] * C' + [A + 2^(n-e)*EA] * C' =
287 // = [B + 2^(n-e)*EB + A + 2^(n-e)*EA] * C' =
288 // = (B'+A') * C' =
289 // = [B + 2^(n-e)*EB + A + 2^(n-e)*EA] * C' =
290 // = [B + A + 2^(n-e)*EB + 2^(n-e)*EA] * C' =
291 // = (B + A) * C' + [2^(n-e)*EB + 2^(n-e)*EA)] * C' =
292 // = (B + A) * C' + [2^(n-e)*EB + 2^(n-e)*EA)] * C*2^c =
293 // = (B + A) * C' + C*(EB + EA)*2^(n-e)*2^c =
294 //
295 // Let EC be the final error with EC = C*(EB + EA)
296 //
297 // = (B + A)*C' + EC*2^(n-e)*2^c =
298 // = (B + A)*C' + EC*2^(n-(e-c))
299 //
300 // Since EC is multiplied by 2^(n-(e-c)) the resulting error contains c
301 // less error bits than the input. c bits are shifted out to the left.
302 // [qed]
303
304 if (C.getBitWidth() != A.getBitWidth()) {
305 ErrorMSBs = (unsigned)-1;
306 return *this;
307 }
308
309 // Multiplying by one is a no-op.
310 if (C.isOneValue()) {
311 return *this;
312 }
313
314 // Multiplying by zero removes the coefficient B and defines all bits.
315 if (C.isNullValue()) {
316 ErrorMSBs = 0;
317 deleteB();
318 }
319
320 // See Proof(2): Trailing zero bits indicate a left shift. This removes
321 // leading bits from the result even if they are undefined.
322 decErrorMSBs(C.countTrailingZeros());
323
324 A *= C;
325 pushBOperation(Mul, C);
326 return *this;
327 }
328
329 /// Apply a logical shift right on the polynomial
lshr(const APInt & C)330 Polynomial &lshr(const APInt &C) {
331 // Theorem(1): (B + A + E*2^(n-e)) >> 1 => (B >> 1) + (A >> 1) + E'*2^(n-e')
332 // where
333 // e' = e + 1,
334 // E is a e-bit number,
335 // E' is a e'-bit number,
336 // holds under the following precondition:
337 // pre(1): A % 2 = 0
338 // pre(2): e < n, (see Theorem(2) for the trivial case with e=n)
339 // where >> expresses a logical shift to the right, with adding zeros.
340 //
341 // We need to show that for every, E there is a E'
342 //
343 // B = b_h * 2^(n-1) + b_m * 2 + b_l
344 // A = a_h * 2^(n-1) + a_m * 2 (pre(1))
345 //
346 // where a_h, b_h, b_l are single bits, and a_m, b_m are (n-2) bit numbers
347 //
348 // Let X = (B + A + E*2^(n-e)) >> 1
349 // Let Y = (B >> 1) + (A >> 1) + E*2^(n-e) >> 1
350 //
351 // X = [B + A + E*2^(n-e)] >> 1 =
352 // = [ b_h * 2^(n-1) + b_m * 2 + b_l +
353 // + a_h * 2^(n-1) + a_m * 2 +
354 // + E * 2^(n-e) ] >> 1 =
355 //
356 // The sum is built by putting the overflow of [a_m + b+n] into the term
357 // 2^(n-1). As there are no more bits beyond 2^(n-1) the overflow within
358 // this bit is discarded. This is expressed by % 2.
359 //
360 // The bit in position 0 cannot overflow into the term (b_m + a_m).
361 //
362 // = [ ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-1) +
363 // + ((b_m + a_m) % 2^(n-2)) * 2 +
364 // + b_l + E * 2^(n-e) ] >> 1 =
365 //
366 // The shift is computed by dividing the terms by 2 and by cutting off
367 // b_l.
368 //
369 // = ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-2) +
370 // + ((b_m + a_m) % 2^(n-2)) +
371 // + E * 2^(n-(e+1)) =
372 //
373 // by the definition in the Theorem e+1 = e'
374 //
375 // = ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-2) +
376 // + ((b_m + a_m) % 2^(n-2)) +
377 // + E * 2^(n-e') =
378 //
379 // Compute Y by applying distributivity first
380 //
381 // Y = (B >> 1) + (A >> 1) + E*2^(n-e') =
382 // = (b_h * 2^(n-1) + b_m * 2 + b_l) >> 1 +
383 // + (a_h * 2^(n-1) + a_m * 2) >> 1 +
384 // + E * 2^(n-e) >> 1 =
385 //
386 // Again, the shift is computed by dividing the terms by 2 and by cutting
387 // off b_l.
388 //
389 // = b_h * 2^(n-2) + b_m +
390 // + a_h * 2^(n-2) + a_m +
391 // + E * 2^(n-(e+1)) =
392 //
393 // Again, the sum is built by putting the overflow of [a_m + b+n] into
394 // the term 2^(n-1). But this time there is room for a second bit in the
395 // term 2^(n-2) we add this bit to a new term and denote it o_h in a
396 // second step.
397 //
398 // = ([b_h + a_h + (b_m + a_m) >> (n-2)] >> 1) * 2^(n-1) +
399 // + ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-2) +
400 // + ((b_m + a_m) % 2^(n-2)) +
401 // + E * 2^(n-(e+1)) =
402 //
403 // Let o_h = [b_h + a_h + (b_m + a_m) >> (n-2)] >> 1
404 // Further replace e+1 by e'.
405 //
406 // = o_h * 2^(n-1) +
407 // + ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-2) +
408 // + ((b_m + a_m) % 2^(n-2)) +
409 // + E * 2^(n-e') =
410 //
411 // Move o_h into the error term and construct E'. To ensure that there is
412 // no 2^x with negative x, this step requires pre(2) (e < n).
413 //
414 // = ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-2) +
415 // + ((b_m + a_m) % 2^(n-2)) +
416 // + o_h * 2^(e'-1) * 2^(n-e') + | pre(2), move 2^(e'-1)
417 // | out of the old exponent
418 // + E * 2^(n-e') =
419 // = ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-2) +
420 // + ((b_m + a_m) % 2^(n-2)) +
421 // + [o_h * 2^(e'-1) + E] * 2^(n-e') + | move 2^(e'-1) out of
422 // | the old exponent
423 //
424 // Let E' = o_h * 2^(e'-1) + E
425 //
426 // = ([b_h + a_h + (b_m + a_m) >> (n-2)] % 2) * 2^(n-2) +
427 // + ((b_m + a_m) % 2^(n-2)) +
428 // + E' * 2^(n-e')
429 //
430 // Because X and Y are distinct only in there error terms and E' can be
431 // constructed as shown the theorem holds.
432 // [qed]
433 //
434 // For completeness in case of the case e=n it is also required to show that
435 // distributivity can be applied.
436 //
437 // In this case Theorem(1) transforms to (the pre-condition on A can also be
438 // dropped)
439 //
440 // Theorem(2): (B + A + E) >> 1 => (B >> 1) + (A >> 1) + E'
441 // where
442 // A, B, E, E' are two's complement numbers with the same bit
443 // width
444 //
445 // Let A + B + E = X
446 // Let (B >> 1) + (A >> 1) = Y
447 //
448 // Therefore we need to show that for every X and Y there is an E' which
449 // makes the equation
450 //
451 // X = Y + E'
452 //
453 // hold. This is trivially the case for E' = X - Y.
454 //
455 // [qed]
456 //
457 // Remark: Distributing lshr with and arbitrary number n can be expressed as
458 // ((((B + A) lshr 1) lshr 1) ... ) {n times}.
459 // This construction induces n additional error bits at the left.
460
461 if (C.getBitWidth() != A.getBitWidth()) {
462 ErrorMSBs = (unsigned)-1;
463 return *this;
464 }
465
466 if (C.isNullValue())
467 return *this;
468
469 // Test if the result will be zero
470 unsigned shiftAmt = C.getZExtValue();
471 if (shiftAmt >= C.getBitWidth())
472 return mul(APInt(C.getBitWidth(), 0));
473
474 // The proof that shiftAmt LSBs are zero for at least one summand is only
475 // possible for the constant number.
476 //
477 // If this can be proven add shiftAmt to the error counter
478 // `ErrorMSBs`. Otherwise set all bits as undefined.
479 if (A.countTrailingZeros() < shiftAmt)
480 ErrorMSBs = A.getBitWidth();
481 else
482 incErrorMSBs(shiftAmt);
483
484 // Apply the operation.
485 pushBOperation(LShr, C);
486 A = A.lshr(shiftAmt);
487
488 return *this;
489 }
490
491 /// Apply a sign-extend or truncate operation on the polynomial.
sextOrTrunc(unsigned n)492 Polynomial &sextOrTrunc(unsigned n) {
493 if (n < A.getBitWidth()) {
494 // Truncate: Clearly undefined Bits on the MSB side are removed
495 // if there are any.
496 decErrorMSBs(A.getBitWidth() - n);
497 A = A.trunc(n);
498 pushBOperation(Trunc, APInt(sizeof(n) * 8, n));
499 }
500 if (n > A.getBitWidth()) {
501 // Extend: Clearly extending first and adding later is different
502 // to adding first and extending later in all extended bits.
503 incErrorMSBs(n - A.getBitWidth());
504 A = A.sext(n);
505 pushBOperation(SExt, APInt(sizeof(n) * 8, n));
506 }
507
508 return *this;
509 }
510
511 /// Test if there is a coefficient B.
isFirstOrder() const512 bool isFirstOrder() const { return V != nullptr; }
513
514 /// Test coefficient B of two Polynomials are equal.
isCompatibleTo(const Polynomial & o) const515 bool isCompatibleTo(const Polynomial &o) const {
516 // The polynomial use different bit width.
517 if (A.getBitWidth() != o.A.getBitWidth())
518 return false;
519
520 // If neither Polynomial has the Coefficient B.
521 if (!isFirstOrder() && !o.isFirstOrder())
522 return true;
523
524 // The index variable is different.
525 if (V != o.V)
526 return false;
527
528 // Check the operations.
529 if (B.size() != o.B.size())
530 return false;
531
532 auto ob = o.B.begin();
533 for (auto &b : B) {
534 if (b != *ob)
535 return false;
536 ob++;
537 }
538
539 return true;
540 }
541
542 /// Subtract two polynomials, return an undefined polynomial if
543 /// subtraction is not possible.
operator -(const Polynomial & o) const544 Polynomial operator-(const Polynomial &o) const {
545 // Return an undefined polynomial if incompatible.
546 if (!isCompatibleTo(o))
547 return Polynomial();
548
549 // If the polynomials are compatible (meaning they have the same
550 // coefficient on B), B is eliminated. Thus a polynomial solely
551 // containing A is returned
552 return Polynomial(A - o.A, std::max(ErrorMSBs, o.ErrorMSBs));
553 }
554
555 /// Subtract a constant from a polynomial,
operator -(uint64_t C) const556 Polynomial operator-(uint64_t C) const {
557 Polynomial Result(*this);
558 Result.A -= C;
559 return Result;
560 }
561
562 /// Add a constant to a polynomial,
operator +(uint64_t C) const563 Polynomial operator+(uint64_t C) const {
564 Polynomial Result(*this);
565 Result.A += C;
566 return Result;
567 }
568
569 /// Returns true if it can be proven that two Polynomials are equal.
isProvenEqualTo(const Polynomial & o)570 bool isProvenEqualTo(const Polynomial &o) {
571 // Subtract both polynomials and test if it is fully defined and zero.
572 Polynomial r = *this - o;
573 return (r.ErrorMSBs == 0) && (!r.isFirstOrder()) && (r.A.isNullValue());
574 }
575
576 /// Print the polynomial into a stream.
print(raw_ostream & OS) const577 void print(raw_ostream &OS) const {
578 OS << "[{#ErrBits:" << ErrorMSBs << "} ";
579
580 if (V) {
581 for (auto b : B)
582 OS << "(";
583 OS << "(" << *V << ") ";
584
585 for (auto b : B) {
586 switch (b.first) {
587 case LShr:
588 OS << "LShr ";
589 break;
590 case Mul:
591 OS << "Mul ";
592 break;
593 case SExt:
594 OS << "SExt ";
595 break;
596 case Trunc:
597 OS << "Trunc ";
598 break;
599 }
600
601 OS << b.second << ") ";
602 }
603 }
604
605 OS << "+ " << A << "]";
606 }
607
608 private:
deleteB()609 void deleteB() {
610 V = nullptr;
611 B.clear();
612 }
613
pushBOperation(const BOps Op,const APInt & C)614 void pushBOperation(const BOps Op, const APInt &C) {
615 if (isFirstOrder()) {
616 B.push_back(std::make_pair(Op, C));
617 return;
618 }
619 }
620 };
621
622 #ifndef NDEBUG
operator <<(raw_ostream & OS,const Polynomial & S)623 static raw_ostream &operator<<(raw_ostream &OS, const Polynomial &S) {
624 S.print(OS);
625 return OS;
626 }
627 #endif
628
629 /// VectorInfo stores abstract the following information for each vector
630 /// element:
631 ///
632 /// 1) The the memory address loaded into the element as Polynomial
633 /// 2) a set of load instruction necessary to construct the vector,
634 /// 3) a set of all other instructions that are necessary to create the vector and
635 /// 4) a pointer value that can be used as relative base for all elements.
636 struct VectorInfo {
637 private:
VectorInfo__anon3482201f0111::VectorInfo638 VectorInfo(const VectorInfo &c) : VTy(c.VTy) {
639 llvm_unreachable(
640 "Copying VectorInfo is neither implemented nor necessary,");
641 }
642
643 public:
644 /// Information of a Vector Element
645 struct ElementInfo {
646 /// Offset Polynomial.
647 Polynomial Ofs;
648
649 /// The Load Instruction used to Load the entry. LI is null if the pointer
650 /// of the load instruction does not point on to the entry
651 LoadInst *LI;
652
ElementInfo__anon3482201f0111::VectorInfo::ElementInfo653 ElementInfo(Polynomial Offset = Polynomial(), LoadInst *LI = nullptr)
654 : Ofs(Offset), LI(LI) {}
655 };
656
657 /// Basic-block the load instructions are within
658 BasicBlock *BB;
659
660 /// Pointer value of all participation load instructions
661 Value *PV;
662
663 /// Participating load instructions
664 std::set<LoadInst *> LIs;
665
666 /// Participating instructions
667 std::set<Instruction *> Is;
668
669 /// Final shuffle-vector instruction
670 ShuffleVectorInst *SVI;
671
672 /// Information of the offset for each vector element
673 ElementInfo *EI;
674
675 /// Vector Type
676 VectorType *const VTy;
677
VectorInfo__anon3482201f0111::VectorInfo678 VectorInfo(VectorType *VTy)
679 : BB(nullptr), PV(nullptr), LIs(), Is(), SVI(nullptr), VTy(VTy) {
680 EI = new ElementInfo[VTy->getNumElements()];
681 }
682
~VectorInfo__anon3482201f0111::VectorInfo683 virtual ~VectorInfo() { delete[] EI; }
684
getDimension__anon3482201f0111::VectorInfo685 unsigned getDimension() const { return VTy->getNumElements(); }
686
687 /// Test if the VectorInfo can be part of an interleaved load with the
688 /// specified factor.
689 ///
690 /// \param Factor of the interleave
691 /// \param DL Targets Datalayout
692 ///
693 /// \returns true if this is possible and false if not
isInterleaved__anon3482201f0111::VectorInfo694 bool isInterleaved(unsigned Factor, const DataLayout &DL) const {
695 unsigned Size = DL.getTypeAllocSize(VTy->getElementType());
696 for (unsigned i = 1; i < getDimension(); i++) {
697 if (!EI[i].Ofs.isProvenEqualTo(EI[0].Ofs + i * Factor * Size)) {
698 return false;
699 }
700 }
701 return true;
702 }
703
704 /// Recursively computes the vector information stored in V.
705 ///
706 /// This function delegates the work to specialized implementations
707 ///
708 /// \param V Value to operate on
709 /// \param Result Result of the computation
710 ///
711 /// \returns false if no sensible information can be gathered.
compute__anon3482201f0111::VectorInfo712 static bool compute(Value *V, VectorInfo &Result, const DataLayout &DL) {
713 ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V);
714 if (SVI)
715 return computeFromSVI(SVI, Result, DL);
716 LoadInst *LI = dyn_cast<LoadInst>(V);
717 if (LI)
718 return computeFromLI(LI, Result, DL);
719 BitCastInst *BCI = dyn_cast<BitCastInst>(V);
720 if (BCI)
721 return computeFromBCI(BCI, Result, DL);
722 return false;
723 }
724
725 /// BitCastInst specialization to compute the vector information.
726 ///
727 /// \param BCI BitCastInst to operate on
728 /// \param Result Result of the computation
729 ///
730 /// \returns false if no sensible information can be gathered.
computeFromBCI__anon3482201f0111::VectorInfo731 static bool computeFromBCI(BitCastInst *BCI, VectorInfo &Result,
732 const DataLayout &DL) {
733 Instruction *Op = dyn_cast<Instruction>(BCI->getOperand(0));
734
735 if (!Op)
736 return false;
737
738 VectorType *VTy = dyn_cast<VectorType>(Op->getType());
739 if (!VTy)
740 return false;
741
742 // We can only cast from large to smaller vectors
743 if (Result.VTy->getNumElements() % VTy->getNumElements())
744 return false;
745
746 unsigned Factor = Result.VTy->getNumElements() / VTy->getNumElements();
747 unsigned NewSize = DL.getTypeAllocSize(Result.VTy->getElementType());
748 unsigned OldSize = DL.getTypeAllocSize(VTy->getElementType());
749
750 if (NewSize * Factor != OldSize)
751 return false;
752
753 VectorInfo Old(VTy);
754 if (!compute(Op, Old, DL))
755 return false;
756
757 for (unsigned i = 0; i < Result.VTy->getNumElements(); i += Factor) {
758 for (unsigned j = 0; j < Factor; j++) {
759 Result.EI[i + j] =
760 ElementInfo(Old.EI[i / Factor].Ofs + j * NewSize,
761 j == 0 ? Old.EI[i / Factor].LI : nullptr);
762 }
763 }
764
765 Result.BB = Old.BB;
766 Result.PV = Old.PV;
767 Result.LIs.insert(Old.LIs.begin(), Old.LIs.end());
768 Result.Is.insert(Old.Is.begin(), Old.Is.end());
769 Result.Is.insert(BCI);
770 Result.SVI = nullptr;
771
772 return true;
773 }
774
775 /// ShuffleVectorInst specialization to compute vector information.
776 ///
777 /// \param SVI ShuffleVectorInst to operate on
778 /// \param Result Result of the computation
779 ///
780 /// Compute the left and the right side vector information and merge them by
781 /// applying the shuffle operation. This function also ensures that the left
782 /// and right side have compatible loads. This means that all loads are with
783 /// in the same basic block and are based on the same pointer.
784 ///
785 /// \returns false if no sensible information can be gathered.
computeFromSVI__anon3482201f0111::VectorInfo786 static bool computeFromSVI(ShuffleVectorInst *SVI, VectorInfo &Result,
787 const DataLayout &DL) {
788 VectorType *ArgTy = dyn_cast<VectorType>(SVI->getOperand(0)->getType());
789 assert(ArgTy && "ShuffleVector Operand is not a VectorType");
790
791 // Compute the left hand vector information.
792 VectorInfo LHS(ArgTy);
793 if (!compute(SVI->getOperand(0), LHS, DL))
794 LHS.BB = nullptr;
795
796 // Compute the right hand vector information.
797 VectorInfo RHS(ArgTy);
798 if (!compute(SVI->getOperand(1), RHS, DL))
799 RHS.BB = nullptr;
800
801 // Neither operand produced sensible results?
802 if (!LHS.BB && !RHS.BB)
803 return false;
804 // Only RHS produced sensible results?
805 else if (!LHS.BB) {
806 Result.BB = RHS.BB;
807 Result.PV = RHS.PV;
808 }
809 // Only LHS produced sensible results?
810 else if (!RHS.BB) {
811 Result.BB = LHS.BB;
812 Result.PV = LHS.PV;
813 }
814 // Both operands produced sensible results?
815 else if ((LHS.BB == RHS.BB) && (LHS.PV == RHS.PV)) {
816 Result.BB = LHS.BB;
817 Result.PV = LHS.PV;
818 }
819 // Both operands produced sensible results but they are incompatible.
820 else {
821 return false;
822 }
823
824 // Merge and apply the operation on the offset information.
825 if (LHS.BB) {
826 Result.LIs.insert(LHS.LIs.begin(), LHS.LIs.end());
827 Result.Is.insert(LHS.Is.begin(), LHS.Is.end());
828 }
829 if (RHS.BB) {
830 Result.LIs.insert(RHS.LIs.begin(), RHS.LIs.end());
831 Result.Is.insert(RHS.Is.begin(), RHS.Is.end());
832 }
833 Result.Is.insert(SVI);
834 Result.SVI = SVI;
835
836 int j = 0;
837 for (int i : SVI->getShuffleMask()) {
838 assert((i < 2 * (signed)ArgTy->getNumElements()) &&
839 "Invalid ShuffleVectorInst (index out of bounds)");
840
841 if (i < 0)
842 Result.EI[j] = ElementInfo();
843 else if (i < (signed)ArgTy->getNumElements()) {
844 if (LHS.BB)
845 Result.EI[j] = LHS.EI[i];
846 else
847 Result.EI[j] = ElementInfo();
848 } else {
849 if (RHS.BB)
850 Result.EI[j] = RHS.EI[i - ArgTy->getNumElements()];
851 else
852 Result.EI[j] = ElementInfo();
853 }
854 j++;
855 }
856
857 return true;
858 }
859
860 /// LoadInst specialization to compute vector information.
861 ///
862 /// This function also acts as abort condition to the recursion.
863 ///
864 /// \param LI LoadInst to operate on
865 /// \param Result Result of the computation
866 ///
867 /// \returns false if no sensible information can be gathered.
computeFromLI__anon3482201f0111::VectorInfo868 static bool computeFromLI(LoadInst *LI, VectorInfo &Result,
869 const DataLayout &DL) {
870 Value *BasePtr;
871 Polynomial Offset;
872
873 if (LI->isVolatile())
874 return false;
875
876 if (LI->isAtomic())
877 return false;
878
879 // Get the base polynomial
880 computePolynomialFromPointer(*LI->getPointerOperand(), Offset, BasePtr, DL);
881
882 Result.BB = LI->getParent();
883 Result.PV = BasePtr;
884 Result.LIs.insert(LI);
885 Result.Is.insert(LI);
886
887 for (unsigned i = 0; i < Result.getDimension(); i++) {
888 Value *Idx[2] = {
889 ConstantInt::get(Type::getInt32Ty(LI->getContext()), 0),
890 ConstantInt::get(Type::getInt32Ty(LI->getContext()), i),
891 };
892 int64_t Ofs = DL.getIndexedOffsetInType(Result.VTy, makeArrayRef(Idx, 2));
893 Result.EI[i] = ElementInfo(Offset + Ofs, i == 0 ? LI : nullptr);
894 }
895
896 return true;
897 }
898
899 /// Recursively compute polynomial of a value.
900 ///
901 /// \param BO Input binary operation
902 /// \param Result Result polynomial
computePolynomialBinOp__anon3482201f0111::VectorInfo903 static void computePolynomialBinOp(BinaryOperator &BO, Polynomial &Result) {
904 Value *LHS = BO.getOperand(0);
905 Value *RHS = BO.getOperand(1);
906
907 // Find the RHS Constant if any
908 ConstantInt *C = dyn_cast<ConstantInt>(RHS);
909 if ((!C) && BO.isCommutative()) {
910 C = dyn_cast<ConstantInt>(LHS);
911 if (C)
912 std::swap(LHS, RHS);
913 }
914
915 switch (BO.getOpcode()) {
916 case Instruction::Add:
917 if (!C)
918 break;
919
920 computePolynomial(*LHS, Result);
921 Result.add(C->getValue());
922 return;
923
924 case Instruction::LShr:
925 if (!C)
926 break;
927
928 computePolynomial(*LHS, Result);
929 Result.lshr(C->getValue());
930 return;
931
932 default:
933 break;
934 }
935
936 Result = Polynomial(&BO);
937 }
938
939 /// Recursively compute polynomial of a value
940 ///
941 /// \param V input value
942 /// \param Result result polynomial
computePolynomial__anon3482201f0111::VectorInfo943 static void computePolynomial(Value &V, Polynomial &Result) {
944 if (auto *BO = dyn_cast<BinaryOperator>(&V))
945 computePolynomialBinOp(*BO, Result);
946 else
947 Result = Polynomial(&V);
948 }
949
950 /// Compute the Polynomial representation of a Pointer type.
951 ///
952 /// \param Ptr input pointer value
953 /// \param Result result polynomial
954 /// \param BasePtr pointer the polynomial is based on
955 /// \param DL Datalayout of the target machine
computePolynomialFromPointer__anon3482201f0111::VectorInfo956 static void computePolynomialFromPointer(Value &Ptr, Polynomial &Result,
957 Value *&BasePtr,
958 const DataLayout &DL) {
959 // Not a pointer type? Return an undefined polynomial
960 PointerType *PtrTy = dyn_cast<PointerType>(Ptr.getType());
961 if (!PtrTy) {
962 Result = Polynomial();
963 BasePtr = nullptr;
964 return;
965 }
966 unsigned PointerBits =
967 DL.getIndexSizeInBits(PtrTy->getPointerAddressSpace());
968
969 /// Skip pointer casts. Return Zero polynomial otherwise
970 if (isa<CastInst>(&Ptr)) {
971 CastInst &CI = *cast<CastInst>(&Ptr);
972 switch (CI.getOpcode()) {
973 case Instruction::BitCast:
974 computePolynomialFromPointer(*CI.getOperand(0), Result, BasePtr, DL);
975 break;
976 default:
977 BasePtr = &Ptr;
978 Polynomial(PointerBits, 0);
979 break;
980 }
981 }
982 /// Resolve GetElementPtrInst.
983 else if (isa<GetElementPtrInst>(&Ptr)) {
984 GetElementPtrInst &GEP = *cast<GetElementPtrInst>(&Ptr);
985
986 APInt BaseOffset(PointerBits, 0);
987
988 // Check if we can compute the Offset with accumulateConstantOffset
989 if (GEP.accumulateConstantOffset(DL, BaseOffset)) {
990 Result = Polynomial(BaseOffset);
991 BasePtr = GEP.getPointerOperand();
992 return;
993 } else {
994 // Otherwise we allow that the last index operand of the GEP is
995 // non-constant.
996 unsigned idxOperand, e;
997 SmallVector<Value *, 4> Indices;
998 for (idxOperand = 1, e = GEP.getNumOperands(); idxOperand < e;
999 idxOperand++) {
1000 ConstantInt *IDX = dyn_cast<ConstantInt>(GEP.getOperand(idxOperand));
1001 if (!IDX)
1002 break;
1003 Indices.push_back(IDX);
1004 }
1005
1006 // It must also be the last operand.
1007 if (idxOperand + 1 != e) {
1008 Result = Polynomial();
1009 BasePtr = nullptr;
1010 return;
1011 }
1012
1013 // Compute the polynomial of the index operand.
1014 computePolynomial(*GEP.getOperand(idxOperand), Result);
1015
1016 // Compute base offset from zero based index, excluding the last
1017 // variable operand.
1018 BaseOffset =
1019 DL.getIndexedOffsetInType(GEP.getSourceElementType(), Indices);
1020
1021 // Apply the operations of GEP to the polynomial.
1022 unsigned ResultSize = DL.getTypeAllocSize(GEP.getResultElementType());
1023 Result.sextOrTrunc(PointerBits);
1024 Result.mul(APInt(PointerBits, ResultSize));
1025 Result.add(BaseOffset);
1026 BasePtr = GEP.getPointerOperand();
1027 }
1028 }
1029 // All other instructions are handled by using the value as base pointer and
1030 // a zero polynomial.
1031 else {
1032 BasePtr = &Ptr;
1033 Polynomial(DL.getIndexSizeInBits(PtrTy->getPointerAddressSpace()), 0);
1034 }
1035 }
1036
1037 #ifndef NDEBUG
print__anon3482201f0111::VectorInfo1038 void print(raw_ostream &OS) const {
1039 if (PV)
1040 OS << *PV;
1041 else
1042 OS << "(none)";
1043 OS << " + ";
1044 for (unsigned i = 0; i < getDimension(); i++)
1045 OS << ((i == 0) ? "[" : ", ") << EI[i].Ofs;
1046 OS << "]";
1047 }
1048 #endif
1049 };
1050
1051 } // anonymous namespace
1052
findPattern(std::list<VectorInfo> & Candidates,std::list<VectorInfo> & InterleavedLoad,unsigned Factor,const DataLayout & DL)1053 bool InterleavedLoadCombineImpl::findPattern(
1054 std::list<VectorInfo> &Candidates, std::list<VectorInfo> &InterleavedLoad,
1055 unsigned Factor, const DataLayout &DL) {
1056 for (auto C0 = Candidates.begin(), E0 = Candidates.end(); C0 != E0; ++C0) {
1057 unsigned i;
1058 // Try to find an interleaved load using the front of Worklist as first line
1059 unsigned Size = DL.getTypeAllocSize(C0->VTy->getElementType());
1060
1061 // List containing iterators pointing to the VectorInfos of the candidates
1062 std::vector<std::list<VectorInfo>::iterator> Res(Factor, Candidates.end());
1063
1064 for (auto C = Candidates.begin(), E = Candidates.end(); C != E; C++) {
1065 if (C->VTy != C0->VTy)
1066 continue;
1067 if (C->BB != C0->BB)
1068 continue;
1069 if (C->PV != C0->PV)
1070 continue;
1071
1072 // Check the current value matches any of factor - 1 remaining lines
1073 for (i = 1; i < Factor; i++) {
1074 if (C->EI[0].Ofs.isProvenEqualTo(C0->EI[0].Ofs + i * Size)) {
1075 Res[i] = C;
1076 }
1077 }
1078
1079 for (i = 1; i < Factor; i++) {
1080 if (Res[i] == Candidates.end())
1081 break;
1082 }
1083 if (i == Factor) {
1084 Res[0] = C0;
1085 break;
1086 }
1087 }
1088
1089 if (Res[0] != Candidates.end()) {
1090 // Move the result into the output
1091 for (unsigned i = 0; i < Factor; i++) {
1092 InterleavedLoad.splice(InterleavedLoad.end(), Candidates, Res[i]);
1093 }
1094
1095 return true;
1096 }
1097 }
1098 return false;
1099 }
1100
1101 LoadInst *
findFirstLoad(const std::set<LoadInst * > & LIs)1102 InterleavedLoadCombineImpl::findFirstLoad(const std::set<LoadInst *> &LIs) {
1103 assert(!LIs.empty() && "No load instructions given.");
1104
1105 // All LIs are within the same BB. Select the first for a reference.
1106 BasicBlock *BB = (*LIs.begin())->getParent();
1107 BasicBlock::iterator FLI =
1108 std::find_if(BB->begin(), BB->end(), [&LIs](Instruction &I) -> bool {
1109 return is_contained(LIs, &I);
1110 });
1111 assert(FLI != BB->end());
1112
1113 return cast<LoadInst>(FLI);
1114 }
1115
combine(std::list<VectorInfo> & InterleavedLoad,OptimizationRemarkEmitter & ORE)1116 bool InterleavedLoadCombineImpl::combine(std::list<VectorInfo> &InterleavedLoad,
1117 OptimizationRemarkEmitter &ORE) {
1118 LLVM_DEBUG(dbgs() << "Checking interleaved load\n");
1119
1120 // The insertion point is the LoadInst which loads the first values. The
1121 // following tests are used to proof that the combined load can be inserted
1122 // just before InsertionPoint.
1123 LoadInst *InsertionPoint = InterleavedLoad.front().EI[0].LI;
1124
1125 // Test if the offset is computed
1126 if (!InsertionPoint)
1127 return false;
1128
1129 std::set<LoadInst *> LIs;
1130 std::set<Instruction *> Is;
1131 std::set<Instruction *> SVIs;
1132
1133 unsigned InterleavedCost;
1134 unsigned InstructionCost = 0;
1135
1136 // Get the interleave factor
1137 unsigned Factor = InterleavedLoad.size();
1138
1139 // Merge all input sets used in analysis
1140 for (auto &VI : InterleavedLoad) {
1141 // Generate a set of all load instructions to be combined
1142 LIs.insert(VI.LIs.begin(), VI.LIs.end());
1143
1144 // Generate a set of all instructions taking part in load
1145 // interleaved. This list excludes the instructions necessary for the
1146 // polynomial construction.
1147 Is.insert(VI.Is.begin(), VI.Is.end());
1148
1149 // Generate the set of the final ShuffleVectorInst.
1150 SVIs.insert(VI.SVI);
1151 }
1152
1153 // There is nothing to combine.
1154 if (LIs.size() < 2)
1155 return false;
1156
1157 // Test if all participating instruction will be dead after the
1158 // transformation. If intermediate results are used, no performance gain can
1159 // be expected. Also sum the cost of the Instructions beeing left dead.
1160 for (auto &I : Is) {
1161 // Compute the old cost
1162 InstructionCost +=
1163 TTI.getInstructionCost(I, TargetTransformInfo::TCK_Latency);
1164
1165 // The final SVIs are allowed not to be dead, all uses will be replaced
1166 if (SVIs.find(I) != SVIs.end())
1167 continue;
1168
1169 // If there are users outside the set to be eliminated, we abort the
1170 // transformation. No gain can be expected.
1171 for (auto *U : I->users()) {
1172 if (Is.find(dyn_cast<Instruction>(U)) == Is.end())
1173 return false;
1174 }
1175 }
1176
1177 // We know that all LoadInst are within the same BB. This guarantees that
1178 // either everything or nothing is loaded.
1179 LoadInst *First = findFirstLoad(LIs);
1180
1181 // To be safe that the loads can be combined, iterate over all loads and test
1182 // that the corresponding defining access dominates first LI. This guarantees
1183 // that there are no aliasing stores in between the loads.
1184 auto FMA = MSSA.getMemoryAccess(First);
1185 for (auto LI : LIs) {
1186 auto MADef = MSSA.getMemoryAccess(LI)->getDefiningAccess();
1187 if (!MSSA.dominates(MADef, FMA))
1188 return false;
1189 }
1190 assert(!LIs.empty() && "There are no LoadInst to combine");
1191
1192 // It is necessary that insertion point dominates all final ShuffleVectorInst.
1193 for (auto &VI : InterleavedLoad) {
1194 if (!DT.dominates(InsertionPoint, VI.SVI))
1195 return false;
1196 }
1197
1198 // All checks are done. Add instructions detectable by InterleavedAccessPass
1199 // The old instruction will are left dead.
1200 IRBuilder<> Builder(InsertionPoint);
1201 Type *ETy = InterleavedLoad.front().SVI->getType()->getElementType();
1202 unsigned ElementsPerSVI =
1203 InterleavedLoad.front().SVI->getType()->getNumElements();
1204 VectorType *ILTy = VectorType::get(ETy, Factor * ElementsPerSVI);
1205
1206 SmallVector<unsigned, 4> Indices;
1207 for (unsigned i = 0; i < Factor; i++)
1208 Indices.push_back(i);
1209 InterleavedCost = TTI.getInterleavedMemoryOpCost(
1210 Instruction::Load, ILTy, Factor, Indices, InsertionPoint->getAlignment(),
1211 InsertionPoint->getPointerAddressSpace());
1212
1213 if (InterleavedCost >= InstructionCost) {
1214 return false;
1215 }
1216
1217 // Create a pointer cast for the wide load.
1218 auto CI = Builder.CreatePointerCast(InsertionPoint->getOperand(0),
1219 ILTy->getPointerTo(),
1220 "interleaved.wide.ptrcast");
1221
1222 // Create the wide load and update the MemorySSA.
1223 auto LI = Builder.CreateAlignedLoad(ILTy, CI, InsertionPoint->getAlignment(),
1224 "interleaved.wide.load");
1225 auto MSSAU = MemorySSAUpdater(&MSSA);
1226 MemoryUse *MSSALoad = cast<MemoryUse>(MSSAU.createMemoryAccessBefore(
1227 LI, nullptr, MSSA.getMemoryAccess(InsertionPoint)));
1228 MSSAU.insertUse(MSSALoad);
1229
1230 // Create the final SVIs and replace all uses.
1231 int i = 0;
1232 for (auto &VI : InterleavedLoad) {
1233 SmallVector<uint32_t, 4> Mask;
1234 for (unsigned j = 0; j < ElementsPerSVI; j++)
1235 Mask.push_back(i + j * Factor);
1236
1237 Builder.SetInsertPoint(VI.SVI);
1238 auto SVI = Builder.CreateShuffleVector(LI, UndefValue::get(LI->getType()),
1239 Mask, "interleaved.shuffle");
1240 VI.SVI->replaceAllUsesWith(SVI);
1241 i++;
1242 }
1243
1244 NumInterleavedLoadCombine++;
1245 ORE.emit([&]() {
1246 return OptimizationRemark(DEBUG_TYPE, "Combined Interleaved Load", LI)
1247 << "Load interleaved combined with factor "
1248 << ore::NV("Factor", Factor);
1249 });
1250
1251 return true;
1252 }
1253
run()1254 bool InterleavedLoadCombineImpl::run() {
1255 OptimizationRemarkEmitter ORE(&F);
1256 bool changed = false;
1257 unsigned MaxFactor = TLI.getMaxSupportedInterleaveFactor();
1258
1259 auto &DL = F.getParent()->getDataLayout();
1260
1261 // Start with the highest factor to avoid combining and recombining.
1262 for (unsigned Factor = MaxFactor; Factor >= 2; Factor--) {
1263 std::list<VectorInfo> Candidates;
1264
1265 for (BasicBlock &BB : F) {
1266 for (Instruction &I : BB) {
1267 if (auto SVI = dyn_cast<ShuffleVectorInst>(&I)) {
1268
1269 Candidates.emplace_back(SVI->getType());
1270
1271 if (!VectorInfo::computeFromSVI(SVI, Candidates.back(), DL)) {
1272 Candidates.pop_back();
1273 continue;
1274 }
1275
1276 if (!Candidates.back().isInterleaved(Factor, DL)) {
1277 Candidates.pop_back();
1278 }
1279 }
1280 }
1281 }
1282
1283 std::list<VectorInfo> InterleavedLoad;
1284 while (findPattern(Candidates, InterleavedLoad, Factor, DL)) {
1285 if (combine(InterleavedLoad, ORE)) {
1286 changed = true;
1287 } else {
1288 // Remove the first element of the Interleaved Load but put the others
1289 // back on the list and continue searching
1290 Candidates.splice(Candidates.begin(), InterleavedLoad,
1291 std::next(InterleavedLoad.begin()),
1292 InterleavedLoad.end());
1293 }
1294 InterleavedLoad.clear();
1295 }
1296 }
1297
1298 return changed;
1299 }
1300
1301 namespace {
1302 /// This pass combines interleaved loads into a pattern detectable by
1303 /// InterleavedAccessPass.
1304 struct InterleavedLoadCombine : public FunctionPass {
1305 static char ID;
1306
InterleavedLoadCombine__anon3482201f0411::InterleavedLoadCombine1307 InterleavedLoadCombine() : FunctionPass(ID) {
1308 initializeInterleavedLoadCombinePass(*PassRegistry::getPassRegistry());
1309 }
1310
getPassName__anon3482201f0411::InterleavedLoadCombine1311 StringRef getPassName() const override {
1312 return "Interleaved Load Combine Pass";
1313 }
1314
runOnFunction__anon3482201f0411::InterleavedLoadCombine1315 bool runOnFunction(Function &F) override {
1316 if (DisableInterleavedLoadCombine)
1317 return false;
1318
1319 auto *TPC = getAnalysisIfAvailable<TargetPassConfig>();
1320 if (!TPC)
1321 return false;
1322
1323 LLVM_DEBUG(dbgs() << "*** " << getPassName() << ": " << F.getName()
1324 << "\n");
1325
1326 return InterleavedLoadCombineImpl(
1327 F, getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
1328 getAnalysis<MemorySSAWrapperPass>().getMSSA(),
1329 TPC->getTM<TargetMachine>())
1330 .run();
1331 }
1332
getAnalysisUsage__anon3482201f0411::InterleavedLoadCombine1333 void getAnalysisUsage(AnalysisUsage &AU) const override {
1334 AU.addRequired<MemorySSAWrapperPass>();
1335 AU.addRequired<DominatorTreeWrapperPass>();
1336 FunctionPass::getAnalysisUsage(AU);
1337 }
1338
1339 private:
1340 };
1341 } // anonymous namespace
1342
1343 char InterleavedLoadCombine::ID = 0;
1344
1345 INITIALIZE_PASS_BEGIN(
1346 InterleavedLoadCombine, DEBUG_TYPE,
1347 "Combine interleaved loads into wide loads and shufflevector instructions",
1348 false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)1349 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
1350 INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)
1351 INITIALIZE_PASS_END(
1352 InterleavedLoadCombine, DEBUG_TYPE,
1353 "Combine interleaved loads into wide loads and shufflevector instructions",
1354 false, false)
1355
1356 FunctionPass *
1357 llvm::createInterleavedLoadCombinePass() {
1358 auto P = new InterleavedLoadCombine();
1359 return P;
1360 }
1361