Bug Summary

File:lib/Transforms/Vectorize/LoopVectorize.cpp
Warning:line 4797, column 11
Called C++ object pointer is null

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name LoopVectorize.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-eagerly-assume -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-7/lib/clang/7.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-7~svn338205/build-llvm/lib/Transforms/Vectorize -I /build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize -I /build/llvm-toolchain-snapshot-7~svn338205/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn338205/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/x86_64-linux-gnu/c++/8 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/x86_64-linux-gnu/c++/8 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/backward -internal-isystem /usr/include/clang/7.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-7/lib/clang/7.0.0/include -internal-externc-isystem /usr/lib/gcc/x86_64-linux-gnu/8/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-7~svn338205/build-llvm/lib/Transforms/Vectorize -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-07-29-043837-17923-1 -x c++ /build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp -faddrsig
1//===- LoopVectorize.cpp - A Loop Vectorizer ------------------------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is the LLVM loop vectorizer. This pass modifies 'vectorizable' loops
11// and generates target-independent LLVM-IR.
12// The vectorizer uses the TargetTransformInfo analysis to estimate the costs
13// of instructions in order to estimate the profitability of vectorization.
14//
15// The loop vectorizer combines consecutive loop iterations into a single
16// 'wide' iteration. After this transformation the index is incremented
17// by the SIMD vector width, and not by one.
18//
19// This pass has three parts:
20// 1. The main loop pass that drives the different parts.
21// 2. LoopVectorizationLegality - A unit that checks for the legality
22// of the vectorization.
23// 3. InnerLoopVectorizer - A unit that performs the actual
24// widening of instructions.
25// 4. LoopVectorizationCostModel - A unit that checks for the profitability
26// of vectorization. It decides on the optimal vector width, which
27// can be one, if vectorization is not profitable.
28//
29// There is a development effort going on to migrate loop vectorizer to the
30// VPlan infrastructure and to introduce outer loop vectorization support (see
31// docs/Proposal/VectorizationPlan.rst and
32// http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html). For this
33// purpose, we temporarily introduced the VPlan-native vectorization path: an
34// alternative vectorization path that is natively implemented on top of the
35// VPlan infrastructure. See EnableVPlanNativePath for enabling.
36//
37//===----------------------------------------------------------------------===//
38//
39// The reduction-variable vectorization is based on the paper:
40// D. Nuzman and R. Henderson. Multi-platform Auto-vectorization.
41//
42// Variable uniformity checks are inspired by:
43// Karrenberg, R. and Hack, S. Whole Function Vectorization.
44//
45// The interleaved access vectorization is based on the paper:
46// Dorit Nuzman, Ira Rosen and Ayal Zaks. Auto-Vectorization of Interleaved
47// Data for SIMD
48//
49// Other ideas/concepts are from:
50// A. Zaks and D. Nuzman. Autovectorization in GCC-two years later.
51//
52// S. Maleki, Y. Gao, M. Garzaran, T. Wong and D. Padua. An Evaluation of
53// Vectorizing Compilers.
54//
55//===----------------------------------------------------------------------===//
56
57#include "llvm/Transforms/Vectorize/LoopVectorize.h"
58#include "LoopVectorizationPlanner.h"
59#include "VPRecipeBuilder.h"
60#include "VPlanHCFGBuilder.h"
61#include "llvm/ADT/APInt.h"
62#include "llvm/ADT/ArrayRef.h"
63#include "llvm/ADT/DenseMap.h"
64#include "llvm/ADT/DenseMapInfo.h"
65#include "llvm/ADT/Hashing.h"
66#include "llvm/ADT/MapVector.h"
67#include "llvm/ADT/None.h"
68#include "llvm/ADT/Optional.h"
69#include "llvm/ADT/STLExtras.h"
70#include "llvm/ADT/SetVector.h"
71#include "llvm/ADT/SmallPtrSet.h"
72#include "llvm/ADT/SmallVector.h"
73#include "llvm/ADT/Statistic.h"
74#include "llvm/ADT/StringRef.h"
75#include "llvm/ADT/Twine.h"
76#include "llvm/ADT/iterator_range.h"
77#include "llvm/Analysis/AssumptionCache.h"
78#include "llvm/Analysis/BasicAliasAnalysis.h"
79#include "llvm/Analysis/BlockFrequencyInfo.h"
80#include "llvm/Analysis/CFG.h"
81#include "llvm/Analysis/CodeMetrics.h"
82#include "llvm/Analysis/DemandedBits.h"
83#include "llvm/Analysis/GlobalsModRef.h"
84#include "llvm/Analysis/LoopAccessAnalysis.h"
85#include "llvm/Analysis/LoopAnalysisManager.h"
86#include "llvm/Analysis/LoopInfo.h"
87#include "llvm/Analysis/LoopIterator.h"
88#include "llvm/Analysis/OptimizationRemarkEmitter.h"
89#include "llvm/Analysis/ScalarEvolution.h"
90#include "llvm/Analysis/ScalarEvolutionExpander.h"
91#include "llvm/Analysis/ScalarEvolutionExpressions.h"
92#include "llvm/Analysis/TargetLibraryInfo.h"
93#include "llvm/Analysis/TargetTransformInfo.h"
94#include "llvm/Analysis/VectorUtils.h"
95#include "llvm/IR/Attributes.h"
96#include "llvm/IR/BasicBlock.h"
97#include "llvm/IR/CFG.h"
98#include "llvm/IR/Constant.h"
99#include "llvm/IR/Constants.h"
100#include "llvm/IR/DataLayout.h"
101#include "llvm/IR/DebugInfoMetadata.h"
102#include "llvm/IR/DebugLoc.h"
103#include "llvm/IR/DerivedTypes.h"
104#include "llvm/IR/DiagnosticInfo.h"
105#include "llvm/IR/Dominators.h"
106#include "llvm/IR/Function.h"
107#include "llvm/IR/IRBuilder.h"
108#include "llvm/IR/InstrTypes.h"
109#include "llvm/IR/Instruction.h"
110#include "llvm/IR/Instructions.h"
111#include "llvm/IR/IntrinsicInst.h"
112#include "llvm/IR/Intrinsics.h"
113#include "llvm/IR/LLVMContext.h"
114#include "llvm/IR/Metadata.h"
115#include "llvm/IR/Module.h"
116#include "llvm/IR/Operator.h"
117#include "llvm/IR/Type.h"
118#include "llvm/IR/Use.h"
119#include "llvm/IR/User.h"
120#include "llvm/IR/Value.h"
121#include "llvm/IR/ValueHandle.h"
122#include "llvm/IR/Verifier.h"
123#include "llvm/Pass.h"
124#include "llvm/Support/Casting.h"
125#include "llvm/Support/CommandLine.h"
126#include "llvm/Support/Compiler.h"
127#include "llvm/Support/Debug.h"
128#include "llvm/Support/ErrorHandling.h"
129#include "llvm/Support/MathExtras.h"
130#include "llvm/Support/raw_ostream.h"
131#include "llvm/Transforms/Utils/BasicBlockUtils.h"
132#include "llvm/Transforms/Utils/LoopSimplify.h"
133#include "llvm/Transforms/Utils/LoopUtils.h"
134#include "llvm/Transforms/Utils/LoopVersioning.h"
135#include "llvm/Transforms/Vectorize/LoopVectorizationLegality.h"
136#include <algorithm>
137#include <cassert>
138#include <cstdint>
139#include <cstdlib>
140#include <functional>
141#include <iterator>
142#include <limits>
143#include <memory>
144#include <string>
145#include <tuple>
146#include <utility>
147#include <vector>
148
149using namespace llvm;
150
151#define LV_NAME"loop-vectorize" "loop-vectorize"
152#define DEBUG_TYPE"loop-vectorize" LV_NAME"loop-vectorize"
153
154STATISTIC(LoopsVectorized, "Number of loops vectorized")static llvm::Statistic LoopsVectorized = {"loop-vectorize", "LoopsVectorized"
, "Number of loops vectorized", {0}, {false}}
;
155STATISTIC(LoopsAnalyzed, "Number of loops analyzed for vectorization")static llvm::Statistic LoopsAnalyzed = {"loop-vectorize", "LoopsAnalyzed"
, "Number of loops analyzed for vectorization", {0}, {false}}
;
156
157/// Loops with a known constant trip count below this number are vectorized only
158/// if no scalar iteration overheads are incurred.
159static cl::opt<unsigned> TinyTripCountVectorThreshold(
160 "vectorizer-min-trip-count", cl::init(16), cl::Hidden,
161 cl::desc("Loops with a constant trip count that is smaller than this "
162 "value are vectorized only if no scalar iteration overheads "
163 "are incurred."));
164
165static cl::opt<bool> MaximizeBandwidth(
166 "vectorizer-maximize-bandwidth", cl::init(false), cl::Hidden,
167 cl::desc("Maximize bandwidth when selecting vectorization factor which "
168 "will be determined by the smallest type in loop."));
169
170static cl::opt<bool> EnableInterleavedMemAccesses(
171 "enable-interleaved-mem-accesses", cl::init(false), cl::Hidden,
172 cl::desc("Enable vectorization on interleaved memory accesses in a loop"));
173
174/// Maximum factor for an interleaved memory access.
175static cl::opt<unsigned> MaxInterleaveGroupFactor(
176 "max-interleave-group-factor", cl::Hidden,
177 cl::desc("Maximum factor for an interleaved access group (default = 8)"),
178 cl::init(8));
179
180/// We don't interleave loops with a known constant trip count below this
181/// number.
182static const unsigned TinyTripCountInterleaveThreshold = 128;
183
184static cl::opt<unsigned> ForceTargetNumScalarRegs(
185 "force-target-num-scalar-regs", cl::init(0), cl::Hidden,
186 cl::desc("A flag that overrides the target's number of scalar registers."));
187
188static cl::opt<unsigned> ForceTargetNumVectorRegs(
189 "force-target-num-vector-regs", cl::init(0), cl::Hidden,
190 cl::desc("A flag that overrides the target's number of vector registers."));
191
192static cl::opt<unsigned> ForceTargetMaxScalarInterleaveFactor(
193 "force-target-max-scalar-interleave", cl::init(0), cl::Hidden,
194 cl::desc("A flag that overrides the target's max interleave factor for "
195 "scalar loops."));
196
197static cl::opt<unsigned> ForceTargetMaxVectorInterleaveFactor(
198 "force-target-max-vector-interleave", cl::init(0), cl::Hidden,
199 cl::desc("A flag that overrides the target's max interleave factor for "
200 "vectorized loops."));
201
202static cl::opt<unsigned> ForceTargetInstructionCost(
203 "force-target-instruction-cost", cl::init(0), cl::Hidden,
204 cl::desc("A flag that overrides the target's expected cost for "
205 "an instruction to a single constant value. Mostly "
206 "useful for getting consistent testing."));
207
208static cl::opt<unsigned> SmallLoopCost(
209 "small-loop-cost", cl::init(20), cl::Hidden,
210 cl::desc(
211 "The cost of a loop that is considered 'small' by the interleaver."));
212
213static cl::opt<bool> LoopVectorizeWithBlockFrequency(
214 "loop-vectorize-with-block-frequency", cl::init(true), cl::Hidden,
215 cl::desc("Enable the use of the block frequency analysis to access PGO "
216 "heuristics minimizing code growth in cold regions and being more "
217 "aggressive in hot regions."));
218
219// Runtime interleave loops for load/store throughput.
220static cl::opt<bool> EnableLoadStoreRuntimeInterleave(
221 "enable-loadstore-runtime-interleave", cl::init(true), cl::Hidden,
222 cl::desc(
223 "Enable runtime interleaving until load/store ports are saturated"));
224
225/// The number of stores in a loop that are allowed to need predication.
226static cl::opt<unsigned> NumberOfStoresToPredicate(
227 "vectorize-num-stores-pred", cl::init(1), cl::Hidden,
228 cl::desc("Max number of stores to be predicated behind an if."));
229
230static cl::opt<bool> EnableIndVarRegisterHeur(
231 "enable-ind-var-reg-heur", cl::init(true), cl::Hidden,
232 cl::desc("Count the induction variable only once when interleaving"));
233
234static cl::opt<bool> EnableCondStoresVectorization(
235 "enable-cond-stores-vec", cl::init(true), cl::Hidden,
236 cl::desc("Enable if predication of stores during vectorization."));
237
238static cl::opt<unsigned> MaxNestedScalarReductionIC(
239 "max-nested-scalar-reduction-interleave", cl::init(2), cl::Hidden,
240 cl::desc("The maximum interleave count to use when interleaving a scalar "
241 "reduction in a nested loop."));
242
243static cl::opt<bool> EnableVPlanNativePath(
244 "enable-vplan-native-path", cl::init(false), cl::Hidden,
245 cl::desc("Enable VPlan-native vectorization path with "
246 "support for outer loop vectorization."));
247
248// This flag enables the stress testing of the VPlan H-CFG construction in the
249// VPlan-native vectorization path. It must be used in conjuction with
250// -enable-vplan-native-path. -vplan-verify-hcfg can also be used to enable the
251// verification of the H-CFGs built.
252static cl::opt<bool> VPlanBuildStressTest(
253 "vplan-build-stress-test", cl::init(false), cl::Hidden,
254 cl::desc(
255 "Build VPlan for every supported loop nest in the function and bail "
256 "out right after the build (stress test the VPlan H-CFG construction "
257 "in the VPlan-native vectorization path)."));
258
259/// A helper function for converting Scalar types to vector types.
260/// If the incoming type is void, we return void. If the VF is 1, we return
261/// the scalar type.
262static Type *ToVectorTy(Type *Scalar, unsigned VF) {
263 if (Scalar->isVoidTy() || VF == 1)
264 return Scalar;
265 return VectorType::get(Scalar, VF);
266}
267
268// FIXME: The following helper functions have multiple implementations
269// in the project. They can be effectively organized in a common Load/Store
270// utilities unit.
271
272/// A helper function that returns the type of loaded or stored value.
273static Type *getMemInstValueType(Value *I) {
274 assert((isa<LoadInst>(I) || isa<StoreInst>(I)) &&(static_cast <bool> ((isa<LoadInst>(I) || isa<
StoreInst>(I)) && "Expected Load or Store instruction"
) ? void (0) : __assert_fail ("(isa<LoadInst>(I) || isa<StoreInst>(I)) && \"Expected Load or Store instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 275, __extension__ __PRETTY_FUNCTION__))
275 "Expected Load or Store instruction")(static_cast <bool> ((isa<LoadInst>(I) || isa<
StoreInst>(I)) && "Expected Load or Store instruction"
) ? void (0) : __assert_fail ("(isa<LoadInst>(I) || isa<StoreInst>(I)) && \"Expected Load or Store instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 275, __extension__ __PRETTY_FUNCTION__))
;
276 if (auto *LI = dyn_cast<LoadInst>(I))
277 return LI->getType();
278 return cast<StoreInst>(I)->getValueOperand()->getType();
279}
280
281/// A helper function that returns the alignment of load or store instruction.
282static unsigned getMemInstAlignment(Value *I) {
283 assert((isa<LoadInst>(I) || isa<StoreInst>(I)) &&(static_cast <bool> ((isa<LoadInst>(I) || isa<
StoreInst>(I)) && "Expected Load or Store instruction"
) ? void (0) : __assert_fail ("(isa<LoadInst>(I) || isa<StoreInst>(I)) && \"Expected Load or Store instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 284, __extension__ __PRETTY_FUNCTION__))
284 "Expected Load or Store instruction")(static_cast <bool> ((isa<LoadInst>(I) || isa<
StoreInst>(I)) && "Expected Load or Store instruction"
) ? void (0) : __assert_fail ("(isa<LoadInst>(I) || isa<StoreInst>(I)) && \"Expected Load or Store instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 284, __extension__ __PRETTY_FUNCTION__))
;
285 if (auto *LI = dyn_cast<LoadInst>(I))
286 return LI->getAlignment();
287 return cast<StoreInst>(I)->getAlignment();
288}
289
290/// A helper function that returns the address space of the pointer operand of
291/// load or store instruction.
292static unsigned getMemInstAddressSpace(Value *I) {
293 assert((isa<LoadInst>(I) || isa<StoreInst>(I)) &&(static_cast <bool> ((isa<LoadInst>(I) || isa<
StoreInst>(I)) && "Expected Load or Store instruction"
) ? void (0) : __assert_fail ("(isa<LoadInst>(I) || isa<StoreInst>(I)) && \"Expected Load or Store instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 294, __extension__ __PRETTY_FUNCTION__))
294 "Expected Load or Store instruction")(static_cast <bool> ((isa<LoadInst>(I) || isa<
StoreInst>(I)) && "Expected Load or Store instruction"
) ? void (0) : __assert_fail ("(isa<LoadInst>(I) || isa<StoreInst>(I)) && \"Expected Load or Store instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 294, __extension__ __PRETTY_FUNCTION__))
;
295 if (auto *LI = dyn_cast<LoadInst>(I))
296 return LI->getPointerAddressSpace();
297 return cast<StoreInst>(I)->getPointerAddressSpace();
298}
299
300/// A helper function that returns true if the given type is irregular. The
301/// type is irregular if its allocated size doesn't equal the store size of an
302/// element of the corresponding vector type at the given vectorization factor.
303static bool hasIrregularType(Type *Ty, const DataLayout &DL, unsigned VF) {
304 // Determine if an array of VF elements of type Ty is "bitcast compatible"
305 // with a <VF x Ty> vector.
306 if (VF > 1) {
307 auto *VectorTy = VectorType::get(Ty, VF);
308 return VF * DL.getTypeAllocSize(Ty) != DL.getTypeStoreSize(VectorTy);
309 }
310
311 // If the vectorization factor is one, we just check if an array of type Ty
312 // requires padding between elements.
313 return DL.getTypeAllocSizeInBits(Ty) != DL.getTypeSizeInBits(Ty);
314}
315
316/// A helper function that returns the reciprocal of the block probability of
317/// predicated blocks. If we return X, we are assuming the predicated block
318/// will execute once for every X iterations of the loop header.
319///
320/// TODO: We should use actual block probability here, if available. Currently,
321/// we always assume predicated blocks have a 50% chance of executing.
322static unsigned getReciprocalPredBlockProb() { return 2; }
323
324/// A helper function that adds a 'fast' flag to floating-point operations.
325static Value *addFastMathFlag(Value *V) {
326 if (isa<FPMathOperator>(V)) {
327 FastMathFlags Flags;
328 Flags.setFast();
329 cast<Instruction>(V)->setFastMathFlags(Flags);
330 }
331 return V;
332}
333
334/// A helper function that returns an integer or floating-point constant with
335/// value C.
336static Constant *getSignedIntOrFpConstant(Type *Ty, int64_t C) {
337 return Ty->isIntegerTy() ? ConstantInt::getSigned(Ty, C)
338 : ConstantFP::get(Ty, C);
339}
340
341namespace llvm {
342
343/// InnerLoopVectorizer vectorizes loops which contain only one basic
344/// block to a specified vectorization factor (VF).
345/// This class performs the widening of scalars into vectors, or multiple
346/// scalars. This class also implements the following features:
347/// * It inserts an epilogue loop for handling loops that don't have iteration
348/// counts that are known to be a multiple of the vectorization factor.
349/// * It handles the code generation for reduction variables.
350/// * Scalarization (implementation using scalars) of un-vectorizable
351/// instructions.
352/// InnerLoopVectorizer does not perform any vectorization-legality
353/// checks, and relies on the caller to check for the different legality
354/// aspects. The InnerLoopVectorizer relies on the
355/// LoopVectorizationLegality class to provide information about the induction
356/// and reduction variables that were found to a given vectorization factor.
357class InnerLoopVectorizer {
358public:
359 InnerLoopVectorizer(Loop *OrigLoop, PredicatedScalarEvolution &PSE,
360 LoopInfo *LI, DominatorTree *DT,
361 const TargetLibraryInfo *TLI,
362 const TargetTransformInfo *TTI, AssumptionCache *AC,
363 OptimizationRemarkEmitter *ORE, unsigned VecWidth,
364 unsigned UnrollFactor, LoopVectorizationLegality *LVL,
365 LoopVectorizationCostModel *CM)
366 : OrigLoop(OrigLoop), PSE(PSE), LI(LI), DT(DT), TLI(TLI), TTI(TTI),
367 AC(AC), ORE(ORE), VF(VecWidth), UF(UnrollFactor),
368 Builder(PSE.getSE()->getContext()),
369 VectorLoopValueMap(UnrollFactor, VecWidth), Legal(LVL), Cost(CM) {}
370 virtual ~InnerLoopVectorizer() = default;
371
372 /// Create a new empty loop. Unlink the old loop and connect the new one.
373 /// Return the pre-header block of the new loop.
374 BasicBlock *createVectorizedLoopSkeleton();
375
376 /// Widen a single instruction within the innermost loop.
377 void widenInstruction(Instruction &I);
378
379 /// Fix the vectorized code, taking care of header phi's, live-outs, and more.
380 void fixVectorizedLoop();
381
382 // Return true if any runtime check is added.
383 bool areSafetyChecksAdded() { return AddedSafetyChecks; }
384
385 /// A type for vectorized values in the new loop. Each value from the
386 /// original loop, when vectorized, is represented by UF vector values in the
387 /// new unrolled loop, where UF is the unroll factor.
388 using VectorParts = SmallVector<Value *, 2>;
389
390 /// Vectorize a single PHINode in a block. This method handles the induction
391 /// variable canonicalization. It supports both VF = 1 for unrolled loops and
392 /// arbitrary length vectors.
393 void widenPHIInstruction(Instruction *PN, unsigned UF, unsigned VF);
394
395 /// A helper function to scalarize a single Instruction in the innermost loop.
396 /// Generates a sequence of scalar instances for each lane between \p MinLane
397 /// and \p MaxLane, times each part between \p MinPart and \p MaxPart,
398 /// inclusive..
399 void scalarizeInstruction(Instruction *Instr, const VPIteration &Instance,
400 bool IfPredicateInstr);
401
402 /// Widen an integer or floating-point induction variable \p IV. If \p Trunc
403 /// is provided, the integer induction variable will first be truncated to
404 /// the corresponding type.
405 void widenIntOrFpInduction(PHINode *IV, TruncInst *Trunc = nullptr);
406
407 /// getOrCreateVectorValue and getOrCreateScalarValue coordinate to generate a
408 /// vector or scalar value on-demand if one is not yet available. When
409 /// vectorizing a loop, we visit the definition of an instruction before its
410 /// uses. When visiting the definition, we either vectorize or scalarize the
411 /// instruction, creating an entry for it in the corresponding map. (In some
412 /// cases, such as induction variables, we will create both vector and scalar
413 /// entries.) Then, as we encounter uses of the definition, we derive values
414 /// for each scalar or vector use unless such a value is already available.
415 /// For example, if we scalarize a definition and one of its uses is vector,
416 /// we build the required vector on-demand with an insertelement sequence
417 /// when visiting the use. Otherwise, if the use is scalar, we can use the
418 /// existing scalar definition.
419 ///
420 /// Return a value in the new loop corresponding to \p V from the original
421 /// loop at unroll index \p Part. If the value has already been vectorized,
422 /// the corresponding vector entry in VectorLoopValueMap is returned. If,
423 /// however, the value has a scalar entry in VectorLoopValueMap, we construct
424 /// a new vector value on-demand by inserting the scalar values into a vector
425 /// with an insertelement sequence. If the value has been neither vectorized
426 /// nor scalarized, it must be loop invariant, so we simply broadcast the
427 /// value into a vector.
428 Value *getOrCreateVectorValue(Value *V, unsigned Part);
429
430 /// Return a value in the new loop corresponding to \p V from the original
431 /// loop at unroll and vector indices \p Instance. If the value has been
432 /// vectorized but not scalarized, the necessary extractelement instruction
433 /// will be generated.
434 Value *getOrCreateScalarValue(Value *V, const VPIteration &Instance);
435
436 /// Construct the vector value of a scalarized value \p V one lane at a time.
437 void packScalarIntoVectorValue(Value *V, const VPIteration &Instance);
438
439 /// Try to vectorize the interleaved access group that \p Instr belongs to.
440 void vectorizeInterleaveGroup(Instruction *Instr);
441
442 /// Vectorize Load and Store instructions, optionally masking the vector
443 /// operations if \p BlockInMask is non-null.
444 void vectorizeMemoryInstruction(Instruction *Instr,
445 VectorParts *BlockInMask = nullptr);
446
447 /// Set the debug location in the builder using the debug location in
448 /// the instruction.
449 void setDebugLocFromInst(IRBuilder<> &B, const Value *Ptr);
450
451protected:
452 friend class LoopVectorizationPlanner;
453
454 /// A small list of PHINodes.
455 using PhiVector = SmallVector<PHINode *, 4>;
456
457 /// A type for scalarized values in the new loop. Each value from the
458 /// original loop, when scalarized, is represented by UF x VF scalar values
459 /// in the new unrolled loop, where UF is the unroll factor and VF is the
460 /// vectorization factor.
461 using ScalarParts = SmallVector<SmallVector<Value *, 4>, 2>;
462
463 /// Set up the values of the IVs correctly when exiting the vector loop.
464 void fixupIVUsers(PHINode *OrigPhi, const InductionDescriptor &II,
465 Value *CountRoundDown, Value *EndValue,
466 BasicBlock *MiddleBlock);
467
468 /// Create a new induction variable inside L.
469 PHINode *createInductionVariable(Loop *L, Value *Start, Value *End,
470 Value *Step, Instruction *DL);
471
472 /// Handle all cross-iteration phis in the header.
473 void fixCrossIterationPHIs();
474
475 /// Fix a first-order recurrence. This is the second phase of vectorizing
476 /// this phi node.
477 void fixFirstOrderRecurrence(PHINode *Phi);
478
479 /// Fix a reduction cross-iteration phi. This is the second phase of
480 /// vectorizing this phi node.
481 void fixReduction(PHINode *Phi);
482
483 /// The Loop exit block may have single value PHI nodes with some
484 /// incoming value. While vectorizing we only handled real values
485 /// that were defined inside the loop and we should have one value for
486 /// each predecessor of its parent basic block. See PR14725.
487 void fixLCSSAPHIs();
488
489 /// Iteratively sink the scalarized operands of a predicated instruction into
490 /// the block that was created for it.
491 void sinkScalarOperands(Instruction *PredInst);
492
493 /// Shrinks vector element sizes to the smallest bitwidth they can be legally
494 /// represented as.
495 void truncateToMinimalBitwidths();
496
497 /// Insert the new loop to the loop hierarchy and pass manager
498 /// and update the analysis passes.
499 void updateAnalysis();
500
501 /// Create a broadcast instruction. This method generates a broadcast
502 /// instruction (shuffle) for loop invariant values and for the induction
503 /// value. If this is the induction variable then we extend it to N, N+1, ...
504 /// this is needed because each iteration in the loop corresponds to a SIMD
505 /// element.
506 virtual Value *getBroadcastInstrs(Value *V);
507
508 /// This function adds (StartIdx, StartIdx + Step, StartIdx + 2*Step, ...)
509 /// to each vector element of Val. The sequence starts at StartIndex.
510 /// \p Opcode is relevant for FP induction variable.
511 virtual Value *getStepVector(Value *Val, int StartIdx, Value *Step,
512 Instruction::BinaryOps Opcode =
513 Instruction::BinaryOpsEnd);
514
515 /// Compute scalar induction steps. \p ScalarIV is the scalar induction
516 /// variable on which to base the steps, \p Step is the size of the step, and
517 /// \p EntryVal is the value from the original loop that maps to the steps.
518 /// Note that \p EntryVal doesn't have to be an induction variable - it
519 /// can also be a truncate instruction.
520 void buildScalarSteps(Value *ScalarIV, Value *Step, Instruction *EntryVal,
521 const InductionDescriptor &ID);
522
523 /// Create a vector induction phi node based on an existing scalar one. \p
524 /// EntryVal is the value from the original loop that maps to the vector phi
525 /// node, and \p Step is the loop-invariant step. If \p EntryVal is a
526 /// truncate instruction, instead of widening the original IV, we widen a
527 /// version of the IV truncated to \p EntryVal's type.
528 void createVectorIntOrFpInductionPHI(const InductionDescriptor &II,
529 Value *Step, Instruction *EntryVal);
530
531 /// Returns true if an instruction \p I should be scalarized instead of
532 /// vectorized for the chosen vectorization factor.
533 bool shouldScalarizeInstruction(Instruction *I) const;
534
535 /// Returns true if we should generate a scalar version of \p IV.
536 bool needsScalarInduction(Instruction *IV) const;
537
538 /// If there is a cast involved in the induction variable \p ID, which should
539 /// be ignored in the vectorized loop body, this function records the
540 /// VectorLoopValue of the respective Phi also as the VectorLoopValue of the
541 /// cast. We had already proved that the casted Phi is equal to the uncasted
542 /// Phi in the vectorized loop (under a runtime guard), and therefore
543 /// there is no need to vectorize the cast - the same value can be used in the
544 /// vector loop for both the Phi and the cast.
545 /// If \p VectorLoopValue is a scalarized value, \p Lane is also specified,
546 /// Otherwise, \p VectorLoopValue is a widened/vectorized value.
547 ///
548 /// \p EntryVal is the value from the original loop that maps to the vector
549 /// phi node and is used to distinguish what is the IV currently being
550 /// processed - original one (if \p EntryVal is a phi corresponding to the
551 /// original IV) or the "newly-created" one based on the proof mentioned above
552 /// (see also buildScalarSteps() and createVectorIntOrFPInductionPHI()). In the
553 /// latter case \p EntryVal is a TruncInst and we must not record anything for
554 /// that IV, but it's error-prone to expect callers of this routine to care
555 /// about that, hence this explicit parameter.
556 void recordVectorLoopValueForInductionCast(const InductionDescriptor &ID,
557 const Instruction *EntryVal,
558 Value *VectorLoopValue,
559 unsigned Part,
560 unsigned Lane = UINT_MAX(2147483647 *2U +1U));
561
562 /// Generate a shuffle sequence that will reverse the vector Vec.
563 virtual Value *reverseVector(Value *Vec);
564
565 /// Returns (and creates if needed) the original loop trip count.
566 Value *getOrCreateTripCount(Loop *NewLoop);
567
568 /// Returns (and creates if needed) the trip count of the widened loop.
569 Value *getOrCreateVectorTripCount(Loop *NewLoop);
570
571 /// Returns a bitcasted value to the requested vector type.
572 /// Also handles bitcasts of vector<float> <-> vector<pointer> types.
573 Value *createBitOrPointerCast(Value *V, VectorType *DstVTy,
574 const DataLayout &DL);
575
576 /// Emit a bypass check to see if the vector trip count is zero, including if
577 /// it overflows.
578 void emitMinimumIterationCountCheck(Loop *L, BasicBlock *Bypass);
579
580 /// Emit a bypass check to see if all of the SCEV assumptions we've
581 /// had to make are correct.
582 void emitSCEVChecks(Loop *L, BasicBlock *Bypass);
583
584 /// Emit bypass checks to check any memory assumptions we may have made.
585 void emitMemRuntimeChecks(Loop *L, BasicBlock *Bypass);
586
587 /// Add additional metadata to \p To that was not present on \p Orig.
588 ///
589 /// Currently this is used to add the noalias annotations based on the
590 /// inserted memchecks. Use this for instructions that are *cloned* into the
591 /// vector loop.
592 void addNewMetadata(Instruction *To, const Instruction *Orig);
593
594 /// Add metadata from one instruction to another.
595 ///
596 /// This includes both the original MDs from \p From and additional ones (\see
597 /// addNewMetadata). Use this for *newly created* instructions in the vector
598 /// loop.
599 void addMetadata(Instruction *To, Instruction *From);
600
601 /// Similar to the previous function but it adds the metadata to a
602 /// vector of instructions.
603 void addMetadata(ArrayRef<Value *> To, Instruction *From);
604
605 /// The original loop.
606 Loop *OrigLoop;
607
608 /// A wrapper around ScalarEvolution used to add runtime SCEV checks. Applies
609 /// dynamic knowledge to simplify SCEV expressions and converts them to a
610 /// more usable form.
611 PredicatedScalarEvolution &PSE;
612
613 /// Loop Info.
614 LoopInfo *LI;
615
616 /// Dominator Tree.
617 DominatorTree *DT;
618
619 /// Alias Analysis.
620 AliasAnalysis *AA;
621
622 /// Target Library Info.
623 const TargetLibraryInfo *TLI;
624
625 /// Target Transform Info.
626 const TargetTransformInfo *TTI;
627
628 /// Assumption Cache.
629 AssumptionCache *AC;
630
631 /// Interface to emit optimization remarks.
632 OptimizationRemarkEmitter *ORE;
633
634 /// LoopVersioning. It's only set up (non-null) if memchecks were
635 /// used.
636 ///
637 /// This is currently only used to add no-alias metadata based on the
638 /// memchecks. The actually versioning is performed manually.
639 std::unique_ptr<LoopVersioning> LVer;
640
641 /// The vectorization SIMD factor to use. Each vector will have this many
642 /// vector elements.
643 unsigned VF;
644
645 /// The vectorization unroll factor to use. Each scalar is vectorized to this
646 /// many different vector instructions.
647 unsigned UF;
648
649 /// The builder that we use
650 IRBuilder<> Builder;
651
652 // --- Vectorization state ---
653
654 /// The vector-loop preheader.
655 BasicBlock *LoopVectorPreHeader;
656
657 /// The scalar-loop preheader.
658 BasicBlock *LoopScalarPreHeader;
659
660 /// Middle Block between the vector and the scalar.
661 BasicBlock *LoopMiddleBlock;
662
663 /// The ExitBlock of the scalar loop.
664 BasicBlock *LoopExitBlock;
665
666 /// The vector loop body.
667 BasicBlock *LoopVectorBody;
668
669 /// The scalar loop body.
670 BasicBlock *LoopScalarBody;
671
672 /// A list of all bypass blocks. The first block is the entry of the loop.
673 SmallVector<BasicBlock *, 4> LoopBypassBlocks;
674
675 /// The new Induction variable which was added to the new block.
676 PHINode *Induction = nullptr;
677
678 /// The induction variable of the old basic block.
679 PHINode *OldInduction = nullptr;
680
681 /// Maps values from the original loop to their corresponding values in the
682 /// vectorized loop. A key value can map to either vector values, scalar
683 /// values or both kinds of values, depending on whether the key was
684 /// vectorized and scalarized.
685 VectorizerValueMap VectorLoopValueMap;
686
687 /// Store instructions that were predicated.
688 SmallVector<Instruction *, 4> PredicatedInstructions;
689
690 /// Trip count of the original loop.
691 Value *TripCount = nullptr;
692
693 /// Trip count of the widened loop (TripCount - TripCount % (VF*UF))
694 Value *VectorTripCount = nullptr;
695
696 /// The legality analysis.
697 LoopVectorizationLegality *Legal;
698
699 /// The profitablity analysis.
700 LoopVectorizationCostModel *Cost;
701
702 // Record whether runtime checks are added.
703 bool AddedSafetyChecks = false;
704
705 // Holds the end values for each induction variable. We save the end values
706 // so we can later fix-up the external users of the induction variables.
707 DenseMap<PHINode *, Value *> IVEndValues;
708};
709
710class InnerLoopUnroller : public InnerLoopVectorizer {
711public:
712 InnerLoopUnroller(Loop *OrigLoop, PredicatedScalarEvolution &PSE,
713 LoopInfo *LI, DominatorTree *DT,
714 const TargetLibraryInfo *TLI,
715 const TargetTransformInfo *TTI, AssumptionCache *AC,
716 OptimizationRemarkEmitter *ORE, unsigned UnrollFactor,
717 LoopVectorizationLegality *LVL,
718 LoopVectorizationCostModel *CM)
719 : InnerLoopVectorizer(OrigLoop, PSE, LI, DT, TLI, TTI, AC, ORE, 1,
720 UnrollFactor, LVL, CM) {}
721
722private:
723 Value *getBroadcastInstrs(Value *V) override;
724 Value *getStepVector(Value *Val, int StartIdx, Value *Step,
725 Instruction::BinaryOps Opcode =
726 Instruction::BinaryOpsEnd) override;
727 Value *reverseVector(Value *Vec) override;
728};
729
730} // end namespace llvm
731
732/// Look for a meaningful debug location on the instruction or it's
733/// operands.
734static Instruction *getDebugLocFromInstOrOperands(Instruction *I) {
735 if (!I)
736 return I;
737
738 DebugLoc Empty;
739 if (I->getDebugLoc() != Empty)
740 return I;
741
742 for (User::op_iterator OI = I->op_begin(), OE = I->op_end(); OI != OE; ++OI) {
743 if (Instruction *OpInst = dyn_cast<Instruction>(*OI))
744 if (OpInst->getDebugLoc() != Empty)
745 return OpInst;
746 }
747
748 return I;
749}
750
751void InnerLoopVectorizer::setDebugLocFromInst(IRBuilder<> &B, const Value *Ptr) {
752 if (const Instruction *Inst = dyn_cast_or_null<Instruction>(Ptr)) {
753 const DILocation *DIL = Inst->getDebugLoc();
754 if (DIL && Inst->getFunction()->isDebugInfoForProfiling() &&
755 !isa<DbgInfoIntrinsic>(Inst))
756 B.SetCurrentDebugLocation(DIL->cloneWithDuplicationFactor(UF * VF));
757 else
758 B.SetCurrentDebugLocation(DIL);
759 } else
760 B.SetCurrentDebugLocation(DebugLoc());
761}
762
763#ifndef NDEBUG
764/// \return string containing a file name and a line # for the given loop.
765static std::string getDebugLocString(const Loop *L) {
766 std::string Result;
767 if (L) {
768 raw_string_ostream OS(Result);
769 if (const DebugLoc LoopDbgLoc = L->getStartLoc())
770 LoopDbgLoc.print(OS);
771 else
772 // Just print the module name.
773 OS << L->getHeader()->getParent()->getParent()->getModuleIdentifier();
774 OS.flush();
775 }
776 return Result;
777}
778#endif
779
780void InnerLoopVectorizer::addNewMetadata(Instruction *To,
781 const Instruction *Orig) {
782 // If the loop was versioned with memchecks, add the corresponding no-alias
783 // metadata.
784 if (LVer && (isa<LoadInst>(Orig) || isa<StoreInst>(Orig)))
785 LVer->annotateInstWithNoAlias(To, Orig);
786}
787
788void InnerLoopVectorizer::addMetadata(Instruction *To,
789 Instruction *From) {
790 propagateMetadata(To, From);
791 addNewMetadata(To, From);
792}
793
794void InnerLoopVectorizer::addMetadata(ArrayRef<Value *> To,
795 Instruction *From) {
796 for (Value *V : To) {
797 if (Instruction *I = dyn_cast<Instruction>(V))
798 addMetadata(I, From);
799 }
800}
801
802namespace llvm {
803
804/// The group of interleaved loads/stores sharing the same stride and
805/// close to each other.
806///
807/// Each member in this group has an index starting from 0, and the largest
808/// index should be less than interleaved factor, which is equal to the absolute
809/// value of the access's stride.
810///
811/// E.g. An interleaved load group of factor 4:
812/// for (unsigned i = 0; i < 1024; i+=4) {
813/// a = A[i]; // Member of index 0
814/// b = A[i+1]; // Member of index 1
815/// d = A[i+3]; // Member of index 3
816/// ...
817/// }
818///
819/// An interleaved store group of factor 4:
820/// for (unsigned i = 0; i < 1024; i+=4) {
821/// ...
822/// A[i] = a; // Member of index 0
823/// A[i+1] = b; // Member of index 1
824/// A[i+2] = c; // Member of index 2
825/// A[i+3] = d; // Member of index 3
826/// }
827///
828/// Note: the interleaved load group could have gaps (missing members), but
829/// the interleaved store group doesn't allow gaps.
830class InterleaveGroup {
831public:
832 InterleaveGroup(Instruction *Instr, int Stride, unsigned Align)
833 : Align(Align), InsertPos(Instr) {
834 assert(Align && "The alignment should be non-zero")(static_cast <bool> (Align && "The alignment should be non-zero"
) ? void (0) : __assert_fail ("Align && \"The alignment should be non-zero\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 834, __extension__ __PRETTY_FUNCTION__))
;
835
836 Factor = std::abs(Stride);
837 assert(Factor > 1 && "Invalid interleave factor")(static_cast <bool> (Factor > 1 && "Invalid interleave factor"
) ? void (0) : __assert_fail ("Factor > 1 && \"Invalid interleave factor\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 837, __extension__ __PRETTY_FUNCTION__))
;
838
839 Reverse = Stride < 0;
840 Members[0] = Instr;
841 }
842
843 bool isReverse() const { return Reverse; }
844 unsigned getFactor() const { return Factor; }
845 unsigned getAlignment() const { return Align; }
846 unsigned getNumMembers() const { return Members.size(); }
847
848 /// Try to insert a new member \p Instr with index \p Index and
849 /// alignment \p NewAlign. The index is related to the leader and it could be
850 /// negative if it is the new leader.
851 ///
852 /// \returns false if the instruction doesn't belong to the group.
853 bool insertMember(Instruction *Instr, int Index, unsigned NewAlign) {
854 assert(NewAlign && "The new member's alignment should be non-zero")(static_cast <bool> (NewAlign && "The new member's alignment should be non-zero"
) ? void (0) : __assert_fail ("NewAlign && \"The new member's alignment should be non-zero\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 854, __extension__ __PRETTY_FUNCTION__))
;
855
856 int Key = Index + SmallestKey;
857
858 // Skip if there is already a member with the same index.
859 if (Members.count(Key))
860 return false;
861
862 if (Key > LargestKey) {
863 // The largest index is always less than the interleave factor.
864 if (Index >= static_cast<int>(Factor))
865 return false;
866
867 LargestKey = Key;
868 } else if (Key < SmallestKey) {
869 // The largest index is always less than the interleave factor.
870 if (LargestKey - Key >= static_cast<int>(Factor))
871 return false;
872
873 SmallestKey = Key;
874 }
875
876 // It's always safe to select the minimum alignment.
877 Align = std::min(Align, NewAlign);
878 Members[Key] = Instr;
879 return true;
880 }
881
882 /// Get the member with the given index \p Index
883 ///
884 /// \returns nullptr if contains no such member.
885 Instruction *getMember(unsigned Index) const {
886 int Key = SmallestKey + Index;
887 if (!Members.count(Key))
888 return nullptr;
889
890 return Members.find(Key)->second;
891 }
892
893 /// Get the index for the given member. Unlike the key in the member
894 /// map, the index starts from 0.
895 unsigned getIndex(Instruction *Instr) const {
896 for (auto I : Members)
897 if (I.second == Instr)
898 return I.first - SmallestKey;
899
900 llvm_unreachable("InterleaveGroup contains no such member")::llvm::llvm_unreachable_internal("InterleaveGroup contains no such member"
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 900)
;
901 }
902
903 Instruction *getInsertPos() const { return InsertPos; }
904 void setInsertPos(Instruction *Inst) { InsertPos = Inst; }
905
906 /// Add metadata (e.g. alias info) from the instructions in this group to \p
907 /// NewInst.
908 ///
909 /// FIXME: this function currently does not add noalias metadata a'la
910 /// addNewMedata. To do that we need to compute the intersection of the
911 /// noalias info from all members.
912 void addMetadata(Instruction *NewInst) const {
913 SmallVector<Value *, 4> VL;
914 std::transform(Members.begin(), Members.end(), std::back_inserter(VL),
915 [](std::pair<int, Instruction *> p) { return p.second; });
916 propagateMetadata(NewInst, VL);
917 }
918
919private:
920 unsigned Factor; // Interleave Factor.
921 bool Reverse;
922 unsigned Align;
923 DenseMap<int, Instruction *> Members;
924 int SmallestKey = 0;
925 int LargestKey = 0;
926
927 // To avoid breaking dependences, vectorized instructions of an interleave
928 // group should be inserted at either the first load or the last store in
929 // program order.
930 //
931 // E.g. %even = load i32 // Insert Position
932 // %add = add i32 %even // Use of %even
933 // %odd = load i32
934 //
935 // store i32 %even
936 // %odd = add i32 // Def of %odd
937 // store i32 %odd // Insert Position
938 Instruction *InsertPos;
939};
940} // end namespace llvm
941
942namespace {
943
944/// Drive the analysis of interleaved memory accesses in the loop.
945///
946/// Use this class to analyze interleaved accesses only when we can vectorize
947/// a loop. Otherwise it's meaningless to do analysis as the vectorization
948/// on interleaved accesses is unsafe.
949///
950/// The analysis collects interleave groups and records the relationships
951/// between the member and the group in a map.
952class InterleavedAccessInfo {
953public:
954 InterleavedAccessInfo(PredicatedScalarEvolution &PSE, Loop *L,
955 DominatorTree *DT, LoopInfo *LI,
956 const LoopAccessInfo *LAI)
957 : PSE(PSE), TheLoop(L), DT(DT), LI(LI), LAI(LAI) {}
958
959 ~InterleavedAccessInfo() {
960 SmallPtrSet<InterleaveGroup *, 4> DelSet;
961 // Avoid releasing a pointer twice.
962 for (auto &I : InterleaveGroupMap)
963 DelSet.insert(I.second);
964 for (auto *Ptr : DelSet)
965 delete Ptr;
966 }
967
968 /// Analyze the interleaved accesses and collect them in interleave
969 /// groups. Substitute symbolic strides using \p Strides.
970 void analyzeInterleaving();
971
972 /// Check if \p Instr belongs to any interleave group.
973 bool isInterleaved(Instruction *Instr) const {
974 return InterleaveGroupMap.count(Instr);
975 }
976
977 /// Get the interleave group that \p Instr belongs to.
978 ///
979 /// \returns nullptr if doesn't have such group.
980 InterleaveGroup *getInterleaveGroup(Instruction *Instr) const {
981 if (InterleaveGroupMap.count(Instr))
982 return InterleaveGroupMap.find(Instr)->second;
983 return nullptr;
984 }
985
986 /// Returns true if an interleaved group that may access memory
987 /// out-of-bounds requires a scalar epilogue iteration for correctness.
988 bool requiresScalarEpilogue() const { return RequiresScalarEpilogue; }
989
990private:
991 /// A wrapper around ScalarEvolution, used to add runtime SCEV checks.
992 /// Simplifies SCEV expressions in the context of existing SCEV assumptions.
993 /// The interleaved access analysis can also add new predicates (for example
994 /// by versioning strides of pointers).
995 PredicatedScalarEvolution &PSE;
996
997 Loop *TheLoop;
998 DominatorTree *DT;
999 LoopInfo *LI;
1000 const LoopAccessInfo *LAI;
1001
1002 /// True if the loop may contain non-reversed interleaved groups with
1003 /// out-of-bounds accesses. We ensure we don't speculatively access memory
1004 /// out-of-bounds by executing at least one scalar epilogue iteration.
1005 bool RequiresScalarEpilogue = false;
1006
1007 /// Holds the relationships between the members and the interleave group.
1008 DenseMap<Instruction *, InterleaveGroup *> InterleaveGroupMap;
1009
1010 /// Holds dependences among the memory accesses in the loop. It maps a source
1011 /// access to a set of dependent sink accesses.
1012 DenseMap<Instruction *, SmallPtrSet<Instruction *, 2>> Dependences;
1013
1014 /// The descriptor for a strided memory access.
1015 struct StrideDescriptor {
1016 StrideDescriptor() = default;
1017 StrideDescriptor(int64_t Stride, const SCEV *Scev, uint64_t Size,
1018 unsigned Align)
1019 : Stride(Stride), Scev(Scev), Size(Size), Align(Align) {}
1020
1021 // The access's stride. It is negative for a reverse access.
1022 int64_t Stride = 0;
1023
1024 // The scalar expression of this access.
1025 const SCEV *Scev = nullptr;
1026
1027 // The size of the memory object.
1028 uint64_t Size = 0;
1029
1030 // The alignment of this access.
1031 unsigned Align = 0;
1032 };
1033
1034 /// A type for holding instructions and their stride descriptors.
1035 using StrideEntry = std::pair<Instruction *, StrideDescriptor>;
1036
1037 /// Create a new interleave group with the given instruction \p Instr,
1038 /// stride \p Stride and alignment \p Align.
1039 ///
1040 /// \returns the newly created interleave group.
1041 InterleaveGroup *createInterleaveGroup(Instruction *Instr, int Stride,
1042 unsigned Align) {
1043 assert(!InterleaveGroupMap.count(Instr) &&(static_cast <bool> (!InterleaveGroupMap.count(Instr) &&
"Already in an interleaved access group") ? void (0) : __assert_fail
("!InterleaveGroupMap.count(Instr) && \"Already in an interleaved access group\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1044, __extension__ __PRETTY_FUNCTION__))
1044 "Already in an interleaved access group")(static_cast <bool> (!InterleaveGroupMap.count(Instr) &&
"Already in an interleaved access group") ? void (0) : __assert_fail
("!InterleaveGroupMap.count(Instr) && \"Already in an interleaved access group\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1044, __extension__ __PRETTY_FUNCTION__))
;
1045 InterleaveGroupMap[Instr] = new InterleaveGroup(Instr, Stride, Align);
1046 return InterleaveGroupMap[Instr];
1047 }
1048
1049 /// Release the group and remove all the relationships.
1050 void releaseGroup(InterleaveGroup *Group) {
1051 for (unsigned i = 0; i < Group->getFactor(); i++)
1052 if (Instruction *Member = Group->getMember(i))
1053 InterleaveGroupMap.erase(Member);
1054
1055 delete Group;
1056 }
1057
1058 /// Collect all the accesses with a constant stride in program order.
1059 void collectConstStrideAccesses(
1060 MapVector<Instruction *, StrideDescriptor> &AccessStrideInfo,
1061 const ValueToValueMap &Strides);
1062
1063 /// Returns true if \p Stride is allowed in an interleaved group.
1064 static bool isStrided(int Stride) {
1065 unsigned Factor = std::abs(Stride);
1066 return Factor >= 2 && Factor <= MaxInterleaveGroupFactor;
1067 }
1068
1069 /// Returns true if \p BB is a predicated block.
1070 bool isPredicated(BasicBlock *BB) const {
1071 return LoopAccessInfo::blockNeedsPredication(BB, TheLoop, DT);
1072 }
1073
1074 /// Returns true if LoopAccessInfo can be used for dependence queries.
1075 bool areDependencesValid() const {
1076 return LAI && LAI->getDepChecker().getDependences();
1077 }
1078
1079 /// Returns true if memory accesses \p A and \p B can be reordered, if
1080 /// necessary, when constructing interleaved groups.
1081 ///
1082 /// \p A must precede \p B in program order. We return false if reordering is
1083 /// not necessary or is prevented because \p A and \p B may be dependent.
1084 bool canReorderMemAccessesForInterleavedGroups(StrideEntry *A,
1085 StrideEntry *B) const {
1086 // Code motion for interleaved accesses can potentially hoist strided loads
1087 // and sink strided stores. The code below checks the legality of the
1088 // following two conditions:
1089 //
1090 // 1. Potentially moving a strided load (B) before any store (A) that
1091 // precedes B, or
1092 //
1093 // 2. Potentially moving a strided store (A) after any load or store (B)
1094 // that A precedes.
1095 //
1096 // It's legal to reorder A and B if we know there isn't a dependence from A
1097 // to B. Note that this determination is conservative since some
1098 // dependences could potentially be reordered safely.
1099
1100 // A is potentially the source of a dependence.
1101 auto *Src = A->first;
1102 auto SrcDes = A->second;
1103
1104 // B is potentially the sink of a dependence.
1105 auto *Sink = B->first;
1106 auto SinkDes = B->second;
1107
1108 // Code motion for interleaved accesses can't violate WAR dependences.
1109 // Thus, reordering is legal if the source isn't a write.
1110 if (!Src->mayWriteToMemory())
1111 return true;
1112
1113 // At least one of the accesses must be strided.
1114 if (!isStrided(SrcDes.Stride) && !isStrided(SinkDes.Stride))
1115 return true;
1116
1117 // If dependence information is not available from LoopAccessInfo,
1118 // conservatively assume the instructions can't be reordered.
1119 if (!areDependencesValid())
1120 return false;
1121
1122 // If we know there is a dependence from source to sink, assume the
1123 // instructions can't be reordered. Otherwise, reordering is legal.
1124 return !Dependences.count(Src) || !Dependences.lookup(Src).count(Sink);
1125 }
1126
1127 /// Collect the dependences from LoopAccessInfo.
1128 ///
1129 /// We process the dependences once during the interleaved access analysis to
1130 /// enable constant-time dependence queries.
1131 void collectDependences() {
1132 if (!areDependencesValid())
1133 return;
1134 auto *Deps = LAI->getDepChecker().getDependences();
1135 for (auto Dep : *Deps)
1136 Dependences[Dep.getSource(*LAI)].insert(Dep.getDestination(*LAI));
1137 }
1138};
1139
1140} // end anonymous namespace
1141
1142static void emitMissedWarning(Function *F, Loop *L,
1143 const LoopVectorizeHints &LH,
1144 OptimizationRemarkEmitter *ORE) {
1145 LH.emitRemarkWithHints();
1146
1147 if (LH.getForce() == LoopVectorizeHints::FK_Enabled) {
1148 if (LH.getWidth() != 1)
1149 ORE->emit(DiagnosticInfoOptimizationFailure(
1150 DEBUG_TYPE"loop-vectorize", "FailedRequestedVectorization",
1151 L->getStartLoc(), L->getHeader())
1152 << "loop not vectorized: "
1153 << "failed explicitly specified loop vectorization");
1154 else if (LH.getInterleave() != 1)
1155 ORE->emit(DiagnosticInfoOptimizationFailure(
1156 DEBUG_TYPE"loop-vectorize", "FailedRequestedInterleaving", L->getStartLoc(),
1157 L->getHeader())
1158 << "loop not interleaved: "
1159 << "failed explicitly specified loop interleaving");
1160 }
1161}
1162
1163namespace llvm {
1164
1165/// LoopVectorizationCostModel - estimates the expected speedups due to
1166/// vectorization.
1167/// In many cases vectorization is not profitable. This can happen because of
1168/// a number of reasons. In this class we mainly attempt to predict the
1169/// expected speedup/slowdowns due to the supported instruction set. We use the
1170/// TargetTransformInfo to query the different backends for the cost of
1171/// different operations.
1172class LoopVectorizationCostModel {
1173public:
1174 LoopVectorizationCostModel(Loop *L, PredicatedScalarEvolution &PSE,
1175 LoopInfo *LI, LoopVectorizationLegality *Legal,
1176 const TargetTransformInfo &TTI,
1177 const TargetLibraryInfo *TLI, DemandedBits *DB,
1178 AssumptionCache *AC,
1179 OptimizationRemarkEmitter *ORE, const Function *F,
1180 const LoopVectorizeHints *Hints,
1181 InterleavedAccessInfo &IAI)
1182 : TheLoop(L), PSE(PSE), LI(LI), Legal(Legal), TTI(TTI), TLI(TLI), DB(DB),
1183 AC(AC), ORE(ORE), TheFunction(F), Hints(Hints), InterleaveInfo(IAI) {}
1184
1185 /// \return An upper bound for the vectorization factor, or None if
1186 /// vectorization should be avoided up front.
1187 Optional<unsigned> computeMaxVF(bool OptForSize);
1188
1189 /// \return The most profitable vectorization factor and the cost of that VF.
1190 /// This method checks every power of two up to MaxVF. If UserVF is not ZERO
1191 /// then this vectorization factor will be selected if vectorization is
1192 /// possible.
1193 VectorizationFactor selectVectorizationFactor(unsigned MaxVF);
1194
1195 /// Setup cost-based decisions for user vectorization factor.
1196 void selectUserVectorizationFactor(unsigned UserVF) {
1197 collectUniformsAndScalars(UserVF);
1198 collectInstsToScalarize(UserVF);
1199 }
1200
1201 /// \return The size (in bits) of the smallest and widest types in the code
1202 /// that needs to be vectorized. We ignore values that remain scalar such as
1203 /// 64 bit loop indices.
1204 std::pair<unsigned, unsigned> getSmallestAndWidestTypes();
1205
1206 /// \return The desired interleave count.
1207 /// If interleave count has been specified by metadata it will be returned.
1208 /// Otherwise, the interleave count is computed and returned. VF and LoopCost
1209 /// are the selected vectorization factor and the cost of the selected VF.
1210 unsigned selectInterleaveCount(bool OptForSize, unsigned VF,
1211 unsigned LoopCost);
1212
1213 /// Memory access instruction may be vectorized in more than one way.
1214 /// Form of instruction after vectorization depends on cost.
1215 /// This function takes cost-based decisions for Load/Store instructions
1216 /// and collects them in a map. This decisions map is used for building
1217 /// the lists of loop-uniform and loop-scalar instructions.
1218 /// The calculated cost is saved with widening decision in order to
1219 /// avoid redundant calculations.
1220 void setCostBasedWideningDecision(unsigned VF);
1221
1222 /// A struct that represents some properties of the register usage
1223 /// of a loop.
1224 struct RegisterUsage {
1225 /// Holds the number of loop invariant values that are used in the loop.
1226 unsigned LoopInvariantRegs;
1227
1228 /// Holds the maximum number of concurrent live intervals in the loop.
1229 unsigned MaxLocalUsers;
1230 };
1231
1232 /// \return Returns information about the register usages of the loop for the
1233 /// given vectorization factors.
1234 SmallVector<RegisterUsage, 8> calculateRegisterUsage(ArrayRef<unsigned> VFs);
1235
1236 /// Collect values we want to ignore in the cost model.
1237 void collectValuesToIgnore();
1238
1239 /// \returns The smallest bitwidth each instruction can be represented with.
1240 /// The vector equivalents of these instructions should be truncated to this
1241 /// type.
1242 const MapVector<Instruction *, uint64_t> &getMinimalBitwidths() const {
1243 return MinBWs;
1244 }
1245
1246 /// \returns True if it is more profitable to scalarize instruction \p I for
1247 /// vectorization factor \p VF.
1248 bool isProfitableToScalarize(Instruction *I, unsigned VF) const {
1249 assert(VF > 1 && "Profitable to scalarize relevant only for VF > 1.")(static_cast <bool> (VF > 1 && "Profitable to scalarize relevant only for VF > 1."
) ? void (0) : __assert_fail ("VF > 1 && \"Profitable to scalarize relevant only for VF > 1.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1249, __extension__ __PRETTY_FUNCTION__))
;
1250 auto Scalars = InstsToScalarize.find(VF);
1251 assert(Scalars != InstsToScalarize.end() &&(static_cast <bool> (Scalars != InstsToScalarize.end() &&
"VF not yet analyzed for scalarization profitability") ? void
(0) : __assert_fail ("Scalars != InstsToScalarize.end() && \"VF not yet analyzed for scalarization profitability\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1252, __extension__ __PRETTY_FUNCTION__))
1252 "VF not yet analyzed for scalarization profitability")(static_cast <bool> (Scalars != InstsToScalarize.end() &&
"VF not yet analyzed for scalarization profitability") ? void
(0) : __assert_fail ("Scalars != InstsToScalarize.end() && \"VF not yet analyzed for scalarization profitability\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1252, __extension__ __PRETTY_FUNCTION__))
;
1253 return Scalars->second.count(I);
1254 }
1255
1256 /// Returns true if \p I is known to be uniform after vectorization.
1257 bool isUniformAfterVectorization(Instruction *I, unsigned VF) const {
1258 if (VF == 1)
1259 return true;
1260 assert(Uniforms.count(VF) && "VF not yet analyzed for uniformity")(static_cast <bool> (Uniforms.count(VF) && "VF not yet analyzed for uniformity"
) ? void (0) : __assert_fail ("Uniforms.count(VF) && \"VF not yet analyzed for uniformity\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1260, __extension__ __PRETTY_FUNCTION__))
;
1261 auto UniformsPerVF = Uniforms.find(VF);
1262 return UniformsPerVF->second.count(I);
1263 }
1264
1265 /// Returns true if \p I is known to be scalar after vectorization.
1266 bool isScalarAfterVectorization(Instruction *I, unsigned VF) const {
1267 if (VF == 1)
1268 return true;
1269 assert(Scalars.count(VF) && "Scalar values are not calculated for VF")(static_cast <bool> (Scalars.count(VF) && "Scalar values are not calculated for VF"
) ? void (0) : __assert_fail ("Scalars.count(VF) && \"Scalar values are not calculated for VF\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1269, __extension__ __PRETTY_FUNCTION__))
;
1270 auto ScalarsPerVF = Scalars.find(VF);
1271 return ScalarsPerVF->second.count(I);
1272 }
1273
1274 /// \returns True if instruction \p I can be truncated to a smaller bitwidth
1275 /// for vectorization factor \p VF.
1276 bool canTruncateToMinimalBitwidth(Instruction *I, unsigned VF) const {
1277 return VF > 1 && MinBWs.count(I) && !isProfitableToScalarize(I, VF) &&
1278 !isScalarAfterVectorization(I, VF);
1279 }
1280
1281 /// Decision that was taken during cost calculation for memory instruction.
1282 enum InstWidening {
1283 CM_Unknown,
1284 CM_Widen, // For consecutive accesses with stride +1.
1285 CM_Widen_Reverse, // For consecutive accesses with stride -1.
1286 CM_Interleave,
1287 CM_GatherScatter,
1288 CM_Scalarize
1289 };
1290
1291 /// Save vectorization decision \p W and \p Cost taken by the cost model for
1292 /// instruction \p I and vector width \p VF.
1293 void setWideningDecision(Instruction *I, unsigned VF, InstWidening W,
1294 unsigned Cost) {
1295 assert(VF >= 2 && "Expected VF >=2")(static_cast <bool> (VF >= 2 && "Expected VF >=2"
) ? void (0) : __assert_fail ("VF >= 2 && \"Expected VF >=2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1295, __extension__ __PRETTY_FUNCTION__))
;
1296 WideningDecisions[std::make_pair(I, VF)] = std::make_pair(W, Cost);
1297 }
1298
1299 /// Save vectorization decision \p W and \p Cost taken by the cost model for
1300 /// interleaving group \p Grp and vector width \p VF.
1301 void setWideningDecision(const InterleaveGroup *Grp, unsigned VF,
1302 InstWidening W, unsigned Cost) {
1303 assert(VF >= 2 && "Expected VF >=2")(static_cast <bool> (VF >= 2 && "Expected VF >=2"
) ? void (0) : __assert_fail ("VF >= 2 && \"Expected VF >=2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1303, __extension__ __PRETTY_FUNCTION__))
;
1304 /// Broadcast this decicion to all instructions inside the group.
1305 /// But the cost will be assigned to one instruction only.
1306 for (unsigned i = 0; i < Grp->getFactor(); ++i) {
1307 if (auto *I = Grp->getMember(i)) {
1308 if (Grp->getInsertPos() == I)
1309 WideningDecisions[std::make_pair(I, VF)] = std::make_pair(W, Cost);
1310 else
1311 WideningDecisions[std::make_pair(I, VF)] = std::make_pair(W, 0);
1312 }
1313 }
1314 }
1315
1316 /// Return the cost model decision for the given instruction \p I and vector
1317 /// width \p VF. Return CM_Unknown if this instruction did not pass
1318 /// through the cost modeling.
1319 InstWidening getWideningDecision(Instruction *I, unsigned VF) {
1320 assert(VF >= 2 && "Expected VF >=2")(static_cast <bool> (VF >= 2 && "Expected VF >=2"
) ? void (0) : __assert_fail ("VF >= 2 && \"Expected VF >=2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1320, __extension__ __PRETTY_FUNCTION__))
;
1321 std::pair<Instruction *, unsigned> InstOnVF = std::make_pair(I, VF);
1322 auto Itr = WideningDecisions.find(InstOnVF);
1323 if (Itr == WideningDecisions.end())
1324 return CM_Unknown;
1325 return Itr->second.first;
1326 }
1327
1328 /// Return the vectorization cost for the given instruction \p I and vector
1329 /// width \p VF.
1330 unsigned getWideningCost(Instruction *I, unsigned VF) {
1331 assert(VF >= 2 && "Expected VF >=2")(static_cast <bool> (VF >= 2 && "Expected VF >=2"
) ? void (0) : __assert_fail ("VF >= 2 && \"Expected VF >=2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1331, __extension__ __PRETTY_FUNCTION__))
;
1332 std::pair<Instruction *, unsigned> InstOnVF = std::make_pair(I, VF);
1333 assert(WideningDecisions.count(InstOnVF) && "The cost is not calculated")(static_cast <bool> (WideningDecisions.count(InstOnVF) &&
"The cost is not calculated") ? void (0) : __assert_fail ("WideningDecisions.count(InstOnVF) && \"The cost is not calculated\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1333, __extension__ __PRETTY_FUNCTION__))
;
1334 return WideningDecisions[InstOnVF].second;
1335 }
1336
1337 /// Return True if instruction \p I is an optimizable truncate whose operand
1338 /// is an induction variable. Such a truncate will be removed by adding a new
1339 /// induction variable with the destination type.
1340 bool isOptimizableIVTruncate(Instruction *I, unsigned VF) {
1341 // If the instruction is not a truncate, return false.
1342 auto *Trunc = dyn_cast<TruncInst>(I);
1343 if (!Trunc)
1344 return false;
1345
1346 // Get the source and destination types of the truncate.
1347 Type *SrcTy = ToVectorTy(cast<CastInst>(I)->getSrcTy(), VF);
1348 Type *DestTy = ToVectorTy(cast<CastInst>(I)->getDestTy(), VF);
1349
1350 // If the truncate is free for the given types, return false. Replacing a
1351 // free truncate with an induction variable would add an induction variable
1352 // update instruction to each iteration of the loop. We exclude from this
1353 // check the primary induction variable since it will need an update
1354 // instruction regardless.
1355 Value *Op = Trunc->getOperand(0);
1356 if (Op != Legal->getPrimaryInduction() && TTI.isTruncateFree(SrcTy, DestTy))
1357 return false;
1358
1359 // If the truncated value is not an induction variable, return false.
1360 return Legal->isInductionPhi(Op);
1361 }
1362
1363 /// Collects the instructions to scalarize for each predicated instruction in
1364 /// the loop.
1365 void collectInstsToScalarize(unsigned VF);
1366
1367 /// Collect Uniform and Scalar values for the given \p VF.
1368 /// The sets depend on CM decision for Load/Store instructions
1369 /// that may be vectorized as interleave, gather-scatter or scalarized.
1370 void collectUniformsAndScalars(unsigned VF) {
1371 // Do the analysis once.
1372 if (VF == 1 || Uniforms.count(VF))
1373 return;
1374 setCostBasedWideningDecision(VF);
1375 collectLoopUniforms(VF);
1376 collectLoopScalars(VF);
1377 }
1378
1379 /// Returns true if the target machine supports masked store operation
1380 /// for the given \p DataType and kind of access to \p Ptr.
1381 bool isLegalMaskedStore(Type *DataType, Value *Ptr) {
1382 return Legal->isConsecutivePtr(Ptr) && TTI.isLegalMaskedStore(DataType);
1383 }
1384
1385 /// Returns true if the target machine supports masked load operation
1386 /// for the given \p DataType and kind of access to \p Ptr.
1387 bool isLegalMaskedLoad(Type *DataType, Value *Ptr) {
1388 return Legal->isConsecutivePtr(Ptr) && TTI.isLegalMaskedLoad(DataType);
1389 }
1390
1391 /// Returns true if the target machine supports masked scatter operation
1392 /// for the given \p DataType.
1393 bool isLegalMaskedScatter(Type *DataType) {
1394 return TTI.isLegalMaskedScatter(DataType);
1395 }
1396
1397 /// Returns true if the target machine supports masked gather operation
1398 /// for the given \p DataType.
1399 bool isLegalMaskedGather(Type *DataType) {
1400 return TTI.isLegalMaskedGather(DataType);
1401 }
1402
1403 /// Returns true if the target machine can represent \p V as a masked gather
1404 /// or scatter operation.
1405 bool isLegalGatherOrScatter(Value *V) {
1406 bool LI = isa<LoadInst>(V);
1407 bool SI = isa<StoreInst>(V);
1408 if (!LI && !SI)
1409 return false;
1410 auto *Ty = getMemInstValueType(V);
1411 return (LI && isLegalMaskedGather(Ty)) || (SI && isLegalMaskedScatter(Ty));
1412 }
1413
1414 /// Returns true if \p I is an instruction that will be scalarized with
1415 /// predication. Such instructions include conditional stores and
1416 /// instructions that may divide by zero.
1417 bool isScalarWithPredication(Instruction *I);
1418
1419 /// Returns true if \p I is a memory instruction with consecutive memory
1420 /// access that can be widened.
1421 bool memoryInstructionCanBeWidened(Instruction *I, unsigned VF = 1);
1422
1423 /// Check if \p Instr belongs to any interleaved access group.
1424 bool isAccessInterleaved(Instruction *Instr) {
1425 return InterleaveInfo.isInterleaved(Instr);
1426 }
1427
1428 /// Get the interleaved access group that \p Instr belongs to.
1429 const InterleaveGroup *getInterleavedAccessGroup(Instruction *Instr) {
1430 return InterleaveInfo.getInterleaveGroup(Instr);
1431 }
1432
1433 /// Returns true if an interleaved group requires a scalar iteration
1434 /// to handle accesses with gaps.
1435 bool requiresScalarEpilogue() const {
1436 return InterleaveInfo.requiresScalarEpilogue();
1437 }
1438
1439private:
1440 unsigned NumPredStores = 0;
1441
1442 /// \return An upper bound for the vectorization factor, larger than zero.
1443 /// One is returned if vectorization should best be avoided due to cost.
1444 unsigned computeFeasibleMaxVF(bool OptForSize, unsigned ConstTripCount);
1445
1446 /// The vectorization cost is a combination of the cost itself and a boolean
1447 /// indicating whether any of the contributing operations will actually
1448 /// operate on
1449 /// vector values after type legalization in the backend. If this latter value
1450 /// is
1451 /// false, then all operations will be scalarized (i.e. no vectorization has
1452 /// actually taken place).
1453 using VectorizationCostTy = std::pair<unsigned, bool>;
1454
1455 /// Returns the expected execution cost. The unit of the cost does
1456 /// not matter because we use the 'cost' units to compare different
1457 /// vector widths. The cost that is returned is *not* normalized by
1458 /// the factor width.
1459 VectorizationCostTy expectedCost(unsigned VF);
1460
1461 /// Returns the execution time cost of an instruction for a given vector
1462 /// width. Vector width of one means scalar.
1463 VectorizationCostTy getInstructionCost(Instruction *I, unsigned VF);
1464
1465 /// The cost-computation logic from getInstructionCost which provides
1466 /// the vector type as an output parameter.
1467 unsigned getInstructionCost(Instruction *I, unsigned VF, Type *&VectorTy);
1468
1469 /// Calculate vectorization cost of memory instruction \p I.
1470 unsigned getMemoryInstructionCost(Instruction *I, unsigned VF);
1471
1472 /// The cost computation for scalarized memory instruction.
1473 unsigned getMemInstScalarizationCost(Instruction *I, unsigned VF);
1474
1475 /// The cost computation for interleaving group of memory instructions.
1476 unsigned getInterleaveGroupCost(Instruction *I, unsigned VF);
1477
1478 /// The cost computation for Gather/Scatter instruction.
1479 unsigned getGatherScatterCost(Instruction *I, unsigned VF);
1480
1481 /// The cost computation for widening instruction \p I with consecutive
1482 /// memory access.
1483 unsigned getConsecutiveMemOpCost(Instruction *I, unsigned VF);
1484
1485 /// The cost calculation for Load instruction \p I with uniform pointer -
1486 /// scalar load + broadcast.
1487 unsigned getUniformMemOpCost(Instruction *I, unsigned VF);
1488
1489 /// Returns whether the instruction is a load or store and will be a emitted
1490 /// as a vector operation.
1491 bool isConsecutiveLoadOrStore(Instruction *I);
1492
1493 /// Returns true if an artificially high cost for emulated masked memrefs
1494 /// should be used.
1495 bool useEmulatedMaskMemRefHack(Instruction *I);
1496
1497 /// Create an analysis remark that explains why vectorization failed
1498 ///
1499 /// \p RemarkName is the identifier for the remark. \return the remark object
1500 /// that can be streamed to.
1501 OptimizationRemarkAnalysis createMissedAnalysis(StringRef RemarkName) {
1502 return createLVMissedAnalysis(Hints->vectorizeAnalysisPassName(),
1503 RemarkName, TheLoop);
1504 }
1505
1506 /// Map of scalar integer values to the smallest bitwidth they can be legally
1507 /// represented as. The vector equivalents of these values should be truncated
1508 /// to this type.
1509 MapVector<Instruction *, uint64_t> MinBWs;
1510
1511 /// A type representing the costs for instructions if they were to be
1512 /// scalarized rather than vectorized. The entries are Instruction-Cost
1513 /// pairs.
1514 using ScalarCostsTy = DenseMap<Instruction *, unsigned>;
1515
1516 /// A set containing all BasicBlocks that are known to present after
1517 /// vectorization as a predicated block.
1518 SmallPtrSet<BasicBlock *, 4> PredicatedBBsAfterVectorization;
1519
1520 /// A map holding scalar costs for different vectorization factors. The
1521 /// presence of a cost for an instruction in the mapping indicates that the
1522 /// instruction will be scalarized when vectorizing with the associated
1523 /// vectorization factor. The entries are VF-ScalarCostTy pairs.
1524 DenseMap<unsigned, ScalarCostsTy> InstsToScalarize;
1525
1526 /// Holds the instructions known to be uniform after vectorization.
1527 /// The data is collected per VF.
1528 DenseMap<unsigned, SmallPtrSet<Instruction *, 4>> Uniforms;
1529
1530 /// Holds the instructions known to be scalar after vectorization.
1531 /// The data is collected per VF.
1532 DenseMap<unsigned, SmallPtrSet<Instruction *, 4>> Scalars;
1533
1534 /// Holds the instructions (address computations) that are forced to be
1535 /// scalarized.
1536 DenseMap<unsigned, SmallPtrSet<Instruction *, 4>> ForcedScalars;
1537
1538 /// Returns the expected difference in cost from scalarizing the expression
1539 /// feeding a predicated instruction \p PredInst. The instructions to
1540 /// scalarize and their scalar costs are collected in \p ScalarCosts. A
1541 /// non-negative return value implies the expression will be scalarized.
1542 /// Currently, only single-use chains are considered for scalarization.
1543 int computePredInstDiscount(Instruction *PredInst, ScalarCostsTy &ScalarCosts,
1544 unsigned VF);
1545
1546 /// Collect the instructions that are uniform after vectorization. An
1547 /// instruction is uniform if we represent it with a single scalar value in
1548 /// the vectorized loop corresponding to each vector iteration. Examples of
1549 /// uniform instructions include pointer operands of consecutive or
1550 /// interleaved memory accesses. Note that although uniformity implies an
1551 /// instruction will be scalar, the reverse is not true. In general, a
1552 /// scalarized instruction will be represented by VF scalar values in the
1553 /// vectorized loop, each corresponding to an iteration of the original
1554 /// scalar loop.
1555 void collectLoopUniforms(unsigned VF);
1556
1557 /// Collect the instructions that are scalar after vectorization. An
1558 /// instruction is scalar if it is known to be uniform or will be scalarized
1559 /// during vectorization. Non-uniform scalarized instructions will be
1560 /// represented by VF values in the vectorized loop, each corresponding to an
1561 /// iteration of the original scalar loop.
1562 void collectLoopScalars(unsigned VF);
1563
1564 /// Keeps cost model vectorization decision and cost for instructions.
1565 /// Right now it is used for memory instructions only.
1566 using DecisionList = DenseMap<std::pair<Instruction *, unsigned>,
1567 std::pair<InstWidening, unsigned>>;
1568
1569 DecisionList WideningDecisions;
1570
1571public:
1572 /// The loop that we evaluate.
1573 Loop *TheLoop;
1574
1575 /// Predicated scalar evolution analysis.
1576 PredicatedScalarEvolution &PSE;
1577
1578 /// Loop Info analysis.
1579 LoopInfo *LI;
1580
1581 /// Vectorization legality.
1582 LoopVectorizationLegality *Legal;
1583
1584 /// Vector target information.
1585 const TargetTransformInfo &TTI;
1586
1587 /// Target Library Info.
1588 const TargetLibraryInfo *TLI;
1589
1590 /// Demanded bits analysis.
1591 DemandedBits *DB;
1592
1593 /// Assumption cache.
1594 AssumptionCache *AC;
1595
1596 /// Interface to emit optimization remarks.
1597 OptimizationRemarkEmitter *ORE;
1598
1599 const Function *TheFunction;
1600
1601 /// Loop Vectorize Hint.
1602 const LoopVectorizeHints *Hints;
1603
1604 /// The interleave access information contains groups of interleaved accesses
1605 /// with the same stride and close to each other.
1606 InterleavedAccessInfo &InterleaveInfo;
1607
1608 /// Values to ignore in the cost model.
1609 SmallPtrSet<const Value *, 16> ValuesToIgnore;
1610
1611 /// Values to ignore in the cost model when VF > 1.
1612 SmallPtrSet<const Value *, 16> VecValuesToIgnore;
1613};
1614
1615} // end namespace llvm
1616
1617// Return true if \p OuterLp is an outer loop annotated with hints for explicit
1618// vectorization. The loop needs to be annotated with #pragma omp simd
1619// simdlen(#) or #pragma clang vectorize(enable) vectorize_width(#). If the
1620// vector length information is not provided, vectorization is not considered
1621// explicit. Interleave hints are not allowed either. These limitations will be
1622// relaxed in the future.
1623// Please, note that we are currently forced to abuse the pragma 'clang
1624// vectorize' semantics. This pragma provides *auto-vectorization hints*
1625// (i.e., LV must check that vectorization is legal) whereas pragma 'omp simd'
1626// provides *explicit vectorization hints* (LV can bypass legal checks and
1627// assume that vectorization is legal). However, both hints are implemented
1628// using the same metadata (llvm.loop.vectorize, processed by
1629// LoopVectorizeHints). This will be fixed in the future when the native IR
1630// representation for pragma 'omp simd' is introduced.
1631static bool isExplicitVecOuterLoop(Loop *OuterLp,
1632 OptimizationRemarkEmitter *ORE) {
1633 assert(!OuterLp->empty() && "This is not an outer loop")(static_cast <bool> (!OuterLp->empty() && "This is not an outer loop"
) ? void (0) : __assert_fail ("!OuterLp->empty() && \"This is not an outer loop\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1633, __extension__ __PRETTY_FUNCTION__))
;
1634 LoopVectorizeHints Hints(OuterLp, true /*DisableInterleaving*/, *ORE);
1635
1636 // Only outer loops with an explicit vectorization hint are supported.
1637 // Unannotated outer loops are ignored.
1638 if (Hints.getForce() == LoopVectorizeHints::FK_Undefined)
1639 return false;
1640
1641 Function *Fn = OuterLp->getHeader()->getParent();
1642 if (!Hints.allowVectorization(Fn, OuterLp, false /*AlwaysVectorize*/)) {
1643 LLVM_DEBUG(dbgs() << "LV: Loop hints prevent outer loop vectorization.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints prevent outer loop vectorization.\n"
; } } while (false)
;
1644 return false;
1645 }
1646
1647 if (!Hints.getWidth()) {
1648 LLVM_DEBUG(dbgs() << "LV: Not vectorizing: No user vector width.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: No user vector width.\n"
; } } while (false)
;
1649 emitMissedWarning(Fn, OuterLp, Hints, ORE);
1650 return false;
1651 }
1652
1653 if (Hints.getInterleave() > 1) {
1654 // TODO: Interleave support is future work.
1655 LLVM_DEBUG(dbgs() << "LV: Not vectorizing: Interleave is not supported for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: Interleave is not supported for "
"outer loops.\n"; } } while (false)
1656 "outer loops.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: Interleave is not supported for "
"outer loops.\n"; } } while (false)
;
1657 emitMissedWarning(Fn, OuterLp, Hints, ORE);
1658 return false;
1659 }
1660
1661 return true;
1662}
1663
1664static void collectSupportedLoops(Loop &L, LoopInfo *LI,
1665 OptimizationRemarkEmitter *ORE,
1666 SmallVectorImpl<Loop *> &V) {
1667 // Collect inner loops and outer loops without irreducible control flow. For
1668 // now, only collect outer loops that have explicit vectorization hints. If we
1669 // are stress testing the VPlan H-CFG construction, we collect the outermost
1670 // loop of every loop nest.
1671 if (L.empty() || VPlanBuildStressTest ||
1672 (EnableVPlanNativePath && isExplicitVecOuterLoop(&L, ORE))) {
1673 LoopBlocksRPO RPOT(&L);
1674 RPOT.perform(LI);
1675 if (!containsIrreducibleCFG<const BasicBlock *>(RPOT, *LI)) {
1676 V.push_back(&L);
1677 // TODO: Collect inner loops inside marked outer loops in case
1678 // vectorization fails for the outer loop. Do not invoke
1679 // 'containsIrreducibleCFG' again for inner loops when the outer loop is
1680 // already known to be reducible. We can use an inherited attribute for
1681 // that.
1682 return;
1683 }
1684 }
1685 for (Loop *InnerL : L)
1686 collectSupportedLoops(*InnerL, LI, ORE, V);
1687}
1688
1689namespace {
1690
1691/// The LoopVectorize Pass.
1692struct LoopVectorize : public FunctionPass {
1693 /// Pass identification, replacement for typeid
1694 static char ID;
1695
1696 LoopVectorizePass Impl;
1697
1698 explicit LoopVectorize(bool NoUnrolling = false, bool AlwaysVectorize = true)
1699 : FunctionPass(ID) {
1700 Impl.DisableUnrolling = NoUnrolling;
1701 Impl.AlwaysVectorize = AlwaysVectorize;
1702 initializeLoopVectorizePass(*PassRegistry::getPassRegistry());
1703 }
1704
1705 bool runOnFunction(Function &F) override {
1706 if (skipFunction(F))
1707 return false;
1708
1709 auto *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
1710 auto *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
1711 auto *TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
1712 auto *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
1713 auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
1714 auto *TLIP = getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
1715 auto *TLI = TLIP ? &TLIP->getTLI() : nullptr;
1716 auto *AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
1717 auto *AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
1718 auto *LAA = &getAnalysis<LoopAccessLegacyAnalysis>();
1719 auto *DB = &getAnalysis<DemandedBitsWrapperPass>().getDemandedBits();
1720 auto *ORE = &getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE();
1721
1722 std::function<const LoopAccessInfo &(Loop &)> GetLAA =
1723 [&](Loop &L) -> const LoopAccessInfo & { return LAA->getInfo(&L); };
1724
1725 return Impl.runImpl(F, *SE, *LI, *TTI, *DT, *BFI, TLI, *DB, *AA, *AC,
1726 GetLAA, *ORE);
1727 }
1728
1729 void getAnalysisUsage(AnalysisUsage &AU) const override {
1730 AU.addRequired<AssumptionCacheTracker>();
1731 AU.addRequired<BlockFrequencyInfoWrapperPass>();
1732 AU.addRequired<DominatorTreeWrapperPass>();
1733 AU.addRequired<LoopInfoWrapperPass>();
1734 AU.addRequired<ScalarEvolutionWrapperPass>();
1735 AU.addRequired<TargetTransformInfoWrapperPass>();
1736 AU.addRequired<AAResultsWrapperPass>();
1737 AU.addRequired<LoopAccessLegacyAnalysis>();
1738 AU.addRequired<DemandedBitsWrapperPass>();
1739 AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
1740 AU.addPreserved<LoopInfoWrapperPass>();
1741 AU.addPreserved<DominatorTreeWrapperPass>();
1742 AU.addPreserved<BasicAAWrapperPass>();
1743 AU.addPreserved<GlobalsAAWrapperPass>();
1744 }
1745};
1746
1747} // end anonymous namespace
1748
1749//===----------------------------------------------------------------------===//
1750// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and
1751// LoopVectorizationCostModel and LoopVectorizationPlanner.
1752//===----------------------------------------------------------------------===//
1753
1754Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) {
1755 // We need to place the broadcast of invariant variables outside the loop,
1756 // but only if it's proven safe to do so. Else, broadcast will be inside
1757 // vector loop body.
1758 Instruction *Instr = dyn_cast<Instruction>(V);
1759 bool SafeToHoist = OrigLoop->isLoopInvariant(V) &&
1760 (!Instr ||
1761 DT->dominates(Instr->getParent(), LoopVectorPreHeader));
1762 // Place the code for broadcasting invariant variables in the new preheader.
1763 IRBuilder<>::InsertPointGuard Guard(Builder);
1764 if (SafeToHoist)
1765 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
1766
1767 // Broadcast the scalar into all locations in the vector.
1768 Value *Shuf = Builder.CreateVectorSplat(VF, V, "broadcast");
1769
1770 return Shuf;
1771}
1772
1773void InnerLoopVectorizer::createVectorIntOrFpInductionPHI(
1774 const InductionDescriptor &II, Value *Step, Instruction *EntryVal) {
1775 assert((isa<PHINode>(EntryVal) || isa<TruncInst>(EntryVal)) &&(static_cast <bool> ((isa<PHINode>(EntryVal) || isa
<TruncInst>(EntryVal)) && "Expected either an induction phi-node or a truncate of it!"
) ? void (0) : __assert_fail ("(isa<PHINode>(EntryVal) || isa<TruncInst>(EntryVal)) && \"Expected either an induction phi-node or a truncate of it!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1776, __extension__ __PRETTY_FUNCTION__))
1776 "Expected either an induction phi-node or a truncate of it!")(static_cast <bool> ((isa<PHINode>(EntryVal) || isa
<TruncInst>(EntryVal)) && "Expected either an induction phi-node or a truncate of it!"
) ? void (0) : __assert_fail ("(isa<PHINode>(EntryVal) || isa<TruncInst>(EntryVal)) && \"Expected either an induction phi-node or a truncate of it!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1776, __extension__ __PRETTY_FUNCTION__))
;
1777 Value *Start = II.getStartValue();
1778
1779 // Construct the initial value of the vector IV in the vector loop preheader
1780 auto CurrIP = Builder.saveIP();
1781 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
1782 if (isa<TruncInst>(EntryVal)) {
1783 assert(Start->getType()->isIntegerTy() &&(static_cast <bool> (Start->getType()->isIntegerTy
() && "Truncation requires an integer type") ? void (
0) : __assert_fail ("Start->getType()->isIntegerTy() && \"Truncation requires an integer type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1784, __extension__ __PRETTY_FUNCTION__))
1784 "Truncation requires an integer type")(static_cast <bool> (Start->getType()->isIntegerTy
() && "Truncation requires an integer type") ? void (
0) : __assert_fail ("Start->getType()->isIntegerTy() && \"Truncation requires an integer type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1784, __extension__ __PRETTY_FUNCTION__))
;
1785 auto *TruncType = cast<IntegerType>(EntryVal->getType());
1786 Step = Builder.CreateTrunc(Step, TruncType);
1787 Start = Builder.CreateCast(Instruction::Trunc, Start, TruncType);
1788 }
1789 Value *SplatStart = Builder.CreateVectorSplat(VF, Start);
1790 Value *SteppedStart =
1791 getStepVector(SplatStart, 0, Step, II.getInductionOpcode());
1792
1793 // We create vector phi nodes for both integer and floating-point induction
1794 // variables. Here, we determine the kind of arithmetic we will perform.
1795 Instruction::BinaryOps AddOp;
1796 Instruction::BinaryOps MulOp;
1797 if (Step->getType()->isIntegerTy()) {
1798 AddOp = Instruction::Add;
1799 MulOp = Instruction::Mul;
1800 } else {
1801 AddOp = II.getInductionOpcode();
1802 MulOp = Instruction::FMul;
1803 }
1804
1805 // Multiply the vectorization factor by the step using integer or
1806 // floating-point arithmetic as appropriate.
1807 Value *ConstVF = getSignedIntOrFpConstant(Step->getType(), VF);
1808 Value *Mul = addFastMathFlag(Builder.CreateBinOp(MulOp, Step, ConstVF));
1809
1810 // Create a vector splat to use in the induction update.
1811 //
1812 // FIXME: If the step is non-constant, we create the vector splat with
1813 // IRBuilder. IRBuilder can constant-fold the multiply, but it doesn't
1814 // handle a constant vector splat.
1815 Value *SplatVF = isa<Constant>(Mul)
1816 ? ConstantVector::getSplat(VF, cast<Constant>(Mul))
1817 : Builder.CreateVectorSplat(VF, Mul);
1818 Builder.restoreIP(CurrIP);
1819
1820 // We may need to add the step a number of times, depending on the unroll
1821 // factor. The last of those goes into the PHI.
1822 PHINode *VecInd = PHINode::Create(SteppedStart->getType(), 2, "vec.ind",
1823 &*LoopVectorBody->getFirstInsertionPt());
1824 VecInd->setDebugLoc(EntryVal->getDebugLoc());
1825 Instruction *LastInduction = VecInd;
1826 for (unsigned Part = 0; Part < UF; ++Part) {
1827 VectorLoopValueMap.setVectorValue(EntryVal, Part, LastInduction);
1828
1829 if (isa<TruncInst>(EntryVal))
1830 addMetadata(LastInduction, EntryVal);
1831 recordVectorLoopValueForInductionCast(II, EntryVal, LastInduction, Part);
1832
1833 LastInduction = cast<Instruction>(addFastMathFlag(
1834 Builder.CreateBinOp(AddOp, LastInduction, SplatVF, "step.add")));
1835 LastInduction->setDebugLoc(EntryVal->getDebugLoc());
1836 }
1837
1838 // Move the last step to the end of the latch block. This ensures consistent
1839 // placement of all induction updates.
1840 auto *LoopVectorLatch = LI->getLoopFor(LoopVectorBody)->getLoopLatch();
1841 auto *Br = cast<BranchInst>(LoopVectorLatch->getTerminator());
1842 auto *ICmp = cast<Instruction>(Br->getCondition());
1843 LastInduction->moveBefore(ICmp);
1844 LastInduction->setName("vec.ind.next");
1845
1846 VecInd->addIncoming(SteppedStart, LoopVectorPreHeader);
1847 VecInd->addIncoming(LastInduction, LoopVectorLatch);
1848}
1849
1850bool InnerLoopVectorizer::shouldScalarizeInstruction(Instruction *I) const {
1851 return Cost->isScalarAfterVectorization(I, VF) ||
1852 Cost->isProfitableToScalarize(I, VF);
1853}
1854
1855bool InnerLoopVectorizer::needsScalarInduction(Instruction *IV) const {
1856 if (shouldScalarizeInstruction(IV))
1857 return true;
1858 auto isScalarInst = [&](User *U) -> bool {
1859 auto *I = cast<Instruction>(U);
1860 return (OrigLoop->contains(I) && shouldScalarizeInstruction(I));
1861 };
1862 return llvm::any_of(IV->users(), isScalarInst);
1863}
1864
1865void InnerLoopVectorizer::recordVectorLoopValueForInductionCast(
1866 const InductionDescriptor &ID, const Instruction *EntryVal,
1867 Value *VectorLoopVal, unsigned Part, unsigned Lane) {
1868 assert((isa<PHINode>(EntryVal) || isa<TruncInst>(EntryVal)) &&(static_cast <bool> ((isa<PHINode>(EntryVal) || isa
<TruncInst>(EntryVal)) && "Expected either an induction phi-node or a truncate of it!"
) ? void (0) : __assert_fail ("(isa<PHINode>(EntryVal) || isa<TruncInst>(EntryVal)) && \"Expected either an induction phi-node or a truncate of it!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1869, __extension__ __PRETTY_FUNCTION__))
1869 "Expected either an induction phi-node or a truncate of it!")(static_cast <bool> ((isa<PHINode>(EntryVal) || isa
<TruncInst>(EntryVal)) && "Expected either an induction phi-node or a truncate of it!"
) ? void (0) : __assert_fail ("(isa<PHINode>(EntryVal) || isa<TruncInst>(EntryVal)) && \"Expected either an induction phi-node or a truncate of it!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1869, __extension__ __PRETTY_FUNCTION__))
;
1870
1871 // This induction variable is not the phi from the original loop but the
1872 // newly-created IV based on the proof that casted Phi is equal to the
1873 // uncasted Phi in the vectorized loop (under a runtime guard possibly). It
1874 // re-uses the same InductionDescriptor that original IV uses but we don't
1875 // have to do any recording in this case - that is done when original IV is
1876 // processed.
1877 if (isa<TruncInst>(EntryVal))
1878 return;
1879
1880 const SmallVectorImpl<Instruction *> &Casts = ID.getCastInsts();
1881 if (Casts.empty())
1882 return;
1883 // Only the first Cast instruction in the Casts vector is of interest.
1884 // The rest of the Casts (if exist) have no uses outside the
1885 // induction update chain itself.
1886 Instruction *CastInst = *Casts.begin();
1887 if (Lane < UINT_MAX(2147483647 *2U +1U))
1888 VectorLoopValueMap.setScalarValue(CastInst, {Part, Lane}, VectorLoopVal);
1889 else
1890 VectorLoopValueMap.setVectorValue(CastInst, Part, VectorLoopVal);
1891}
1892
1893void InnerLoopVectorizer::widenIntOrFpInduction(PHINode *IV, TruncInst *Trunc) {
1894 assert((IV->getType()->isIntegerTy() || IV != OldInduction) &&(static_cast <bool> ((IV->getType()->isIntegerTy(
) || IV != OldInduction) && "Primary induction variable must have an integer type"
) ? void (0) : __assert_fail ("(IV->getType()->isIntegerTy() || IV != OldInduction) && \"Primary induction variable must have an integer type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1895, __extension__ __PRETTY_FUNCTION__))
1895 "Primary induction variable must have an integer type")(static_cast <bool> ((IV->getType()->isIntegerTy(
) || IV != OldInduction) && "Primary induction variable must have an integer type"
) ? void (0) : __assert_fail ("(IV->getType()->isIntegerTy() || IV != OldInduction) && \"Primary induction variable must have an integer type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1895, __extension__ __PRETTY_FUNCTION__))
;
1896
1897 auto II = Legal->getInductionVars()->find(IV);
1898 assert(II != Legal->getInductionVars()->end() && "IV is not an induction")(static_cast <bool> (II != Legal->getInductionVars()
->end() && "IV is not an induction") ? void (0) : __assert_fail
("II != Legal->getInductionVars()->end() && \"IV is not an induction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1898, __extension__ __PRETTY_FUNCTION__))
;
1899
1900 auto ID = II->second;
1901 assert(IV->getType() == ID.getStartValue()->getType() && "Types must match")(static_cast <bool> (IV->getType() == ID.getStartValue
()->getType() && "Types must match") ? void (0) : __assert_fail
("IV->getType() == ID.getStartValue()->getType() && \"Types must match\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1901, __extension__ __PRETTY_FUNCTION__))
;
1902
1903 // The scalar value to broadcast. This will be derived from the canonical
1904 // induction variable.
1905 Value *ScalarIV = nullptr;
1906
1907 // The value from the original loop to which we are mapping the new induction
1908 // variable.
1909 Instruction *EntryVal = Trunc ? cast<Instruction>(Trunc) : IV;
1910
1911 // True if we have vectorized the induction variable.
1912 auto VectorizedIV = false;
1913
1914 // Determine if we want a scalar version of the induction variable. This is
1915 // true if the induction variable itself is not widened, or if it has at
1916 // least one user in the loop that is not widened.
1917 auto NeedsScalarIV = VF > 1 && needsScalarInduction(EntryVal);
1918
1919 // Generate code for the induction step. Note that induction steps are
1920 // required to be loop-invariant
1921 assert(PSE.getSE()->isLoopInvariant(ID.getStep(), OrigLoop) &&(static_cast <bool> (PSE.getSE()->isLoopInvariant(ID
.getStep(), OrigLoop) && "Induction step should be loop invariant"
) ? void (0) : __assert_fail ("PSE.getSE()->isLoopInvariant(ID.getStep(), OrigLoop) && \"Induction step should be loop invariant\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1922, __extension__ __PRETTY_FUNCTION__))
1922 "Induction step should be loop invariant")(static_cast <bool> (PSE.getSE()->isLoopInvariant(ID
.getStep(), OrigLoop) && "Induction step should be loop invariant"
) ? void (0) : __assert_fail ("PSE.getSE()->isLoopInvariant(ID.getStep(), OrigLoop) && \"Induction step should be loop invariant\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1922, __extension__ __PRETTY_FUNCTION__))
;
1923 auto &DL = OrigLoop->getHeader()->getModule()->getDataLayout();
1924 Value *Step = nullptr;
1925 if (PSE.getSE()->isSCEVable(IV->getType())) {
1926 SCEVExpander Exp(*PSE.getSE(), DL, "induction");
1927 Step = Exp.expandCodeFor(ID.getStep(), ID.getStep()->getType(),
1928 LoopVectorPreHeader->getTerminator());
1929 } else {
1930 Step = cast<SCEVUnknown>(ID.getStep())->getValue();
1931 }
1932
1933 // Try to create a new independent vector induction variable. If we can't
1934 // create the phi node, we will splat the scalar induction variable in each
1935 // loop iteration.
1936 if (VF > 1 && !shouldScalarizeInstruction(EntryVal)) {
1937 createVectorIntOrFpInductionPHI(ID, Step, EntryVal);
1938 VectorizedIV = true;
1939 }
1940
1941 // If we haven't yet vectorized the induction variable, or if we will create
1942 // a scalar one, we need to define the scalar induction variable and step
1943 // values. If we were given a truncation type, truncate the canonical
1944 // induction variable and step. Otherwise, derive these values from the
1945 // induction descriptor.
1946 if (!VectorizedIV || NeedsScalarIV) {
1947 ScalarIV = Induction;
1948 if (IV != OldInduction) {
1949 ScalarIV = IV->getType()->isIntegerTy()
1950 ? Builder.CreateSExtOrTrunc(Induction, IV->getType())
1951 : Builder.CreateCast(Instruction::SIToFP, Induction,
1952 IV->getType());
1953 ScalarIV = ID.transform(Builder, ScalarIV, PSE.getSE(), DL);
1954 ScalarIV->setName("offset.idx");
1955 }
1956 if (Trunc) {
1957 auto *TruncType = cast<IntegerType>(Trunc->getType());
1958 assert(Step->getType()->isIntegerTy() &&(static_cast <bool> (Step->getType()->isIntegerTy
() && "Truncation requires an integer step") ? void (
0) : __assert_fail ("Step->getType()->isIntegerTy() && \"Truncation requires an integer step\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1959, __extension__ __PRETTY_FUNCTION__))
1959 "Truncation requires an integer step")(static_cast <bool> (Step->getType()->isIntegerTy
() && "Truncation requires an integer step") ? void (
0) : __assert_fail ("Step->getType()->isIntegerTy() && \"Truncation requires an integer step\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1959, __extension__ __PRETTY_FUNCTION__))
;
1960 ScalarIV = Builder.CreateTrunc(ScalarIV, TruncType);
1961 Step = Builder.CreateTrunc(Step, TruncType);
1962 }
1963 }
1964
1965 // If we haven't yet vectorized the induction variable, splat the scalar
1966 // induction variable, and build the necessary step vectors.
1967 // TODO: Don't do it unless the vectorized IV is really required.
1968 if (!VectorizedIV) {
1969 Value *Broadcasted = getBroadcastInstrs(ScalarIV);
1970 for (unsigned Part = 0; Part < UF; ++Part) {
1971 Value *EntryPart =
1972 getStepVector(Broadcasted, VF * Part, Step, ID.getInductionOpcode());
1973 VectorLoopValueMap.setVectorValue(EntryVal, Part, EntryPart);
1974 if (Trunc)
1975 addMetadata(EntryPart, Trunc);
1976 recordVectorLoopValueForInductionCast(ID, EntryVal, EntryPart, Part);
1977 }
1978 }
1979
1980 // If an induction variable is only used for counting loop iterations or
1981 // calculating addresses, it doesn't need to be widened. Create scalar steps
1982 // that can be used by instructions we will later scalarize. Note that the
1983 // addition of the scalar steps will not increase the number of instructions
1984 // in the loop in the common case prior to InstCombine. We will be trading
1985 // one vector extract for each scalar step.
1986 if (NeedsScalarIV)
1987 buildScalarSteps(ScalarIV, Step, EntryVal, ID);
1988}
1989
1990Value *InnerLoopVectorizer::getStepVector(Value *Val, int StartIdx, Value *Step,
1991 Instruction::BinaryOps BinOp) {
1992 // Create and check the types.
1993 assert(Val->getType()->isVectorTy() && "Must be a vector")(static_cast <bool> (Val->getType()->isVectorTy()
&& "Must be a vector") ? void (0) : __assert_fail ("Val->getType()->isVectorTy() && \"Must be a vector\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1993, __extension__ __PRETTY_FUNCTION__))
;
1994 int VLen = Val->getType()->getVectorNumElements();
1995
1996 Type *STy = Val->getType()->getScalarType();
1997 assert((STy->isIntegerTy() || STy->isFloatingPointTy()) &&(static_cast <bool> ((STy->isIntegerTy() || STy->
isFloatingPointTy()) && "Induction Step must be an integer or FP"
) ? void (0) : __assert_fail ("(STy->isIntegerTy() || STy->isFloatingPointTy()) && \"Induction Step must be an integer or FP\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1998, __extension__ __PRETTY_FUNCTION__))
1998 "Induction Step must be an integer or FP")(static_cast <bool> ((STy->isIntegerTy() || STy->
isFloatingPointTy()) && "Induction Step must be an integer or FP"
) ? void (0) : __assert_fail ("(STy->isIntegerTy() || STy->isFloatingPointTy()) && \"Induction Step must be an integer or FP\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1998, __extension__ __PRETTY_FUNCTION__))
;
1999 assert(Step->getType() == STy && "Step has wrong type")(static_cast <bool> (Step->getType() == STy &&
"Step has wrong type") ? void (0) : __assert_fail ("Step->getType() == STy && \"Step has wrong type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1999, __extension__ __PRETTY_FUNCTION__))
;
2000
2001 SmallVector<Constant *, 8> Indices;
2002
2003 if (STy->isIntegerTy()) {
2004 // Create a vector of consecutive numbers from zero to VF.
2005 for (int i = 0; i < VLen; ++i)
2006 Indices.push_back(ConstantInt::get(STy, StartIdx + i));
2007
2008 // Add the consecutive indices to the vector value.
2009 Constant *Cv = ConstantVector::get(Indices);
2010 assert(Cv->getType() == Val->getType() && "Invalid consecutive vec")(static_cast <bool> (Cv->getType() == Val->getType
() && "Invalid consecutive vec") ? void (0) : __assert_fail
("Cv->getType() == Val->getType() && \"Invalid consecutive vec\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2010, __extension__ __PRETTY_FUNCTION__))
;
2011 Step = Builder.CreateVectorSplat(VLen, Step);
2012 assert(Step->getType() == Val->getType() && "Invalid step vec")(static_cast <bool> (Step->getType() == Val->getType
() && "Invalid step vec") ? void (0) : __assert_fail (
"Step->getType() == Val->getType() && \"Invalid step vec\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2012, __extension__ __PRETTY_FUNCTION__))
;
2013 // FIXME: The newly created binary instructions should contain nsw/nuw flags,
2014 // which can be found from the original scalar operations.
2015 Step = Builder.CreateMul(Cv, Step);
2016 return Builder.CreateAdd(Val, Step, "induction");
2017 }
2018
2019 // Floating point induction.
2020 assert((BinOp == Instruction::FAdd || BinOp == Instruction::FSub) &&(static_cast <bool> ((BinOp == Instruction::FAdd || BinOp
== Instruction::FSub) && "Binary Opcode should be specified for FP induction"
) ? void (0) : __assert_fail ("(BinOp == Instruction::FAdd || BinOp == Instruction::FSub) && \"Binary Opcode should be specified for FP induction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2021, __extension__ __PRETTY_FUNCTION__))
2021 "Binary Opcode should be specified for FP induction")(static_cast <bool> ((BinOp == Instruction::FAdd || BinOp
== Instruction::FSub) && "Binary Opcode should be specified for FP induction"
) ? void (0) : __assert_fail ("(BinOp == Instruction::FAdd || BinOp == Instruction::FSub) && \"Binary Opcode should be specified for FP induction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2021, __extension__ __PRETTY_FUNCTION__))
;
2022 // Create a vector of consecutive numbers from zero to VF.
2023 for (int i = 0; i < VLen; ++i)
2024 Indices.push_back(ConstantFP::get(STy, (double)(StartIdx + i)));
2025
2026 // Add the consecutive indices to the vector value.
2027 Constant *Cv = ConstantVector::get(Indices);
2028
2029 Step = Builder.CreateVectorSplat(VLen, Step);
2030
2031 // Floating point operations had to be 'fast' to enable the induction.
2032 FastMathFlags Flags;
2033 Flags.setFast();
2034
2035 Value *MulOp = Builder.CreateFMul(Cv, Step);
2036 if (isa<Instruction>(MulOp))
2037 // Have to check, MulOp may be a constant
2038 cast<Instruction>(MulOp)->setFastMathFlags(Flags);
2039
2040 Value *BOp = Builder.CreateBinOp(BinOp, Val, MulOp, "induction");
2041 if (isa<Instruction>(BOp))
2042 cast<Instruction>(BOp)->setFastMathFlags(Flags);
2043 return BOp;
2044}
2045
2046void InnerLoopVectorizer::buildScalarSteps(Value *ScalarIV, Value *Step,
2047 Instruction *EntryVal,
2048 const InductionDescriptor &ID) {
2049 // We shouldn't have to build scalar steps if we aren't vectorizing.
2050 assert(VF > 1 && "VF should be greater than one")(static_cast <bool> (VF > 1 && "VF should be greater than one"
) ? void (0) : __assert_fail ("VF > 1 && \"VF should be greater than one\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2050, __extension__ __PRETTY_FUNCTION__))
;
2051
2052 // Get the value type and ensure it and the step have the same integer type.
2053 Type *ScalarIVTy = ScalarIV->getType()->getScalarType();
2054 assert(ScalarIVTy == Step->getType() &&(static_cast <bool> (ScalarIVTy == Step->getType() &&
"Val and Step should have the same type") ? void (0) : __assert_fail
("ScalarIVTy == Step->getType() && \"Val and Step should have the same type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2055, __extension__ __PRETTY_FUNCTION__))
2055 "Val and Step should have the same type")(static_cast <bool> (ScalarIVTy == Step->getType() &&
"Val and Step should have the same type") ? void (0) : __assert_fail
("ScalarIVTy == Step->getType() && \"Val and Step should have the same type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2055, __extension__ __PRETTY_FUNCTION__))
;
2056
2057 // We build scalar steps for both integer and floating-point induction
2058 // variables. Here, we determine the kind of arithmetic we will perform.
2059 Instruction::BinaryOps AddOp;
2060 Instruction::BinaryOps MulOp;
2061 if (ScalarIVTy->isIntegerTy()) {
2062 AddOp = Instruction::Add;
2063 MulOp = Instruction::Mul;
2064 } else {
2065 AddOp = ID.getInductionOpcode();
2066 MulOp = Instruction::FMul;
2067 }
2068
2069 // Determine the number of scalars we need to generate for each unroll
2070 // iteration. If EntryVal is uniform, we only need to generate the first
2071 // lane. Otherwise, we generate all VF values.
2072 unsigned Lanes =
2073 Cost->isUniformAfterVectorization(cast<Instruction>(EntryVal), VF) ? 1
2074 : VF;
2075 // Compute the scalar steps and save the results in VectorLoopValueMap.
2076 for (unsigned Part = 0; Part < UF; ++Part) {
2077 for (unsigned Lane = 0; Lane < Lanes; ++Lane) {
2078 auto *StartIdx = getSignedIntOrFpConstant(ScalarIVTy, VF * Part + Lane);
2079 auto *Mul = addFastMathFlag(Builder.CreateBinOp(MulOp, StartIdx, Step));
2080 auto *Add = addFastMathFlag(Builder.CreateBinOp(AddOp, ScalarIV, Mul));
2081 VectorLoopValueMap.setScalarValue(EntryVal, {Part, Lane}, Add);
2082 recordVectorLoopValueForInductionCast(ID, EntryVal, Add, Part, Lane);
2083 }
2084 }
2085}
2086
2087Value *InnerLoopVectorizer::getOrCreateVectorValue(Value *V, unsigned Part) {
2088 assert(V != Induction && "The new induction variable should not be used.")(static_cast <bool> (V != Induction && "The new induction variable should not be used."
) ? void (0) : __assert_fail ("V != Induction && \"The new induction variable should not be used.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2088, __extension__ __PRETTY_FUNCTION__))
;
2089 assert(!V->getType()->isVectorTy() && "Can't widen a vector")(static_cast <bool> (!V->getType()->isVectorTy() &&
"Can't widen a vector") ? void (0) : __assert_fail ("!V->getType()->isVectorTy() && \"Can't widen a vector\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2089, __extension__ __PRETTY_FUNCTION__))
;
2090 assert(!V->getType()->isVoidTy() && "Type does not produce a value")(static_cast <bool> (!V->getType()->isVoidTy() &&
"Type does not produce a value") ? void (0) : __assert_fail (
"!V->getType()->isVoidTy() && \"Type does not produce a value\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2090, __extension__ __PRETTY_FUNCTION__))
;
2091
2092 // If we have a stride that is replaced by one, do it here.
2093 if (Legal->hasStride(V))
2094 V = ConstantInt::get(V->getType(), 1);
2095
2096 // If we have a vector mapped to this value, return it.
2097 if (VectorLoopValueMap.hasVectorValue(V, Part))
2098 return VectorLoopValueMap.getVectorValue(V, Part);
2099
2100 // If the value has not been vectorized, check if it has been scalarized
2101 // instead. If it has been scalarized, and we actually need the value in
2102 // vector form, we will construct the vector values on demand.
2103 if (VectorLoopValueMap.hasAnyScalarValue(V)) {
2104 Value *ScalarValue = VectorLoopValueMap.getScalarValue(V, {Part, 0});
2105
2106 // If we've scalarized a value, that value should be an instruction.
2107 auto *I = cast<Instruction>(V);
2108
2109 // If we aren't vectorizing, we can just copy the scalar map values over to
2110 // the vector map.
2111 if (VF == 1) {
2112 VectorLoopValueMap.setVectorValue(V, Part, ScalarValue);
2113 return ScalarValue;
2114 }
2115
2116 // Get the last scalar instruction we generated for V and Part. If the value
2117 // is known to be uniform after vectorization, this corresponds to lane zero
2118 // of the Part unroll iteration. Otherwise, the last instruction is the one
2119 // we created for the last vector lane of the Part unroll iteration.
2120 unsigned LastLane = Cost->isUniformAfterVectorization(I, VF) ? 0 : VF - 1;
2121 auto *LastInst = cast<Instruction>(
2122 VectorLoopValueMap.getScalarValue(V, {Part, LastLane}));
2123
2124 // Set the insert point after the last scalarized instruction. This ensures
2125 // the insertelement sequence will directly follow the scalar definitions.
2126 auto OldIP = Builder.saveIP();
2127 auto NewIP = std::next(BasicBlock::iterator(LastInst));
2128 Builder.SetInsertPoint(&*NewIP);
2129
2130 // However, if we are vectorizing, we need to construct the vector values.
2131 // If the value is known to be uniform after vectorization, we can just
2132 // broadcast the scalar value corresponding to lane zero for each unroll
2133 // iteration. Otherwise, we construct the vector values using insertelement
2134 // instructions. Since the resulting vectors are stored in
2135 // VectorLoopValueMap, we will only generate the insertelements once.
2136 Value *VectorValue = nullptr;
2137 if (Cost->isUniformAfterVectorization(I, VF)) {
2138 VectorValue = getBroadcastInstrs(ScalarValue);
2139 VectorLoopValueMap.setVectorValue(V, Part, VectorValue);
2140 } else {
2141 // Initialize packing with insertelements to start from undef.
2142 Value *Undef = UndefValue::get(VectorType::get(V->getType(), VF));
2143 VectorLoopValueMap.setVectorValue(V, Part, Undef);
2144 for (unsigned Lane = 0; Lane < VF; ++Lane)
2145 packScalarIntoVectorValue(V, {Part, Lane});
2146 VectorValue = VectorLoopValueMap.getVectorValue(V, Part);
2147 }
2148 Builder.restoreIP(OldIP);
2149 return VectorValue;
2150 }
2151
2152 // If this scalar is unknown, assume that it is a constant or that it is
2153 // loop invariant. Broadcast V and save the value for future uses.
2154 Value *B = getBroadcastInstrs(V);
2155 VectorLoopValueMap.setVectorValue(V, Part, B);
2156 return B;
2157}
2158
2159Value *
2160InnerLoopVectorizer::getOrCreateScalarValue(Value *V,
2161 const VPIteration &Instance) {
2162 // If the value is not an instruction contained in the loop, it should
2163 // already be scalar.
2164 if (OrigLoop->isLoopInvariant(V))
2165 return V;
2166
2167 assert(Instance.Lane > 0(static_cast <bool> (Instance.Lane > 0 ? !Cost->isUniformAfterVectorization
(cast<Instruction>(V), VF) : true && "Uniform values only have lane zero"
) ? void (0) : __assert_fail ("Instance.Lane > 0 ? !Cost->isUniformAfterVectorization(cast<Instruction>(V), VF) : true && \"Uniform values only have lane zero\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2169, __extension__ __PRETTY_FUNCTION__))
2168 ? !Cost->isUniformAfterVectorization(cast<Instruction>(V), VF)(static_cast <bool> (Instance.Lane > 0 ? !Cost->isUniformAfterVectorization
(cast<Instruction>(V), VF) : true && "Uniform values only have lane zero"
) ? void (0) : __assert_fail ("Instance.Lane > 0 ? !Cost->isUniformAfterVectorization(cast<Instruction>(V), VF) : true && \"Uniform values only have lane zero\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2169, __extension__ __PRETTY_FUNCTION__))
2169 : true && "Uniform values only have lane zero")(static_cast <bool> (Instance.Lane > 0 ? !Cost->isUniformAfterVectorization
(cast<Instruction>(V), VF) : true && "Uniform values only have lane zero"
) ? void (0) : __assert_fail ("Instance.Lane > 0 ? !Cost->isUniformAfterVectorization(cast<Instruction>(V), VF) : true && \"Uniform values only have lane zero\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2169, __extension__ __PRETTY_FUNCTION__))
;
2170
2171 // If the value from the original loop has not been vectorized, it is
2172 // represented by UF x VF scalar values in the new loop. Return the requested
2173 // scalar value.
2174 if (VectorLoopValueMap.hasScalarValue(V, Instance))
2175 return VectorLoopValueMap.getScalarValue(V, Instance);
2176
2177 // If the value has not been scalarized, get its entry in VectorLoopValueMap
2178 // for the given unroll part. If this entry is not a vector type (i.e., the
2179 // vectorization factor is one), there is no need to generate an
2180 // extractelement instruction.
2181 auto *U = getOrCreateVectorValue(V, Instance.Part);
2182 if (!U->getType()->isVectorTy()) {
2183 assert(VF == 1 && "Value not scalarized has non-vector type")(static_cast <bool> (VF == 1 && "Value not scalarized has non-vector type"
) ? void (0) : __assert_fail ("VF == 1 && \"Value not scalarized has non-vector type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2183, __extension__ __PRETTY_FUNCTION__))
;
2184 return U;
2185 }
2186
2187 // Otherwise, the value from the original loop has been vectorized and is
2188 // represented by UF vector values. Extract and return the requested scalar
2189 // value from the appropriate vector lane.
2190 return Builder.CreateExtractElement(U, Builder.getInt32(Instance.Lane));
2191}
2192
2193void InnerLoopVectorizer::packScalarIntoVectorValue(
2194 Value *V, const VPIteration &Instance) {
2195 assert(V != Induction && "The new induction variable should not be used.")(static_cast <bool> (V != Induction && "The new induction variable should not be used."
) ? void (0) : __assert_fail ("V != Induction && \"The new induction variable should not be used.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2195, __extension__ __PRETTY_FUNCTION__))
;
2196 assert(!V->getType()->isVectorTy() && "Can't pack a vector")(static_cast <bool> (!V->getType()->isVectorTy() &&
"Can't pack a vector") ? void (0) : __assert_fail ("!V->getType()->isVectorTy() && \"Can't pack a vector\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2196, __extension__ __PRETTY_FUNCTION__))
;
2197 assert(!V->getType()->isVoidTy() && "Type does not produce a value")(static_cast <bool> (!V->getType()->isVoidTy() &&
"Type does not produce a value") ? void (0) : __assert_fail (
"!V->getType()->isVoidTy() && \"Type does not produce a value\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2197, __extension__ __PRETTY_FUNCTION__))
;
2198
2199 Value *ScalarInst = VectorLoopValueMap.getScalarValue(V, Instance);
2200 Value *VectorValue = VectorLoopValueMap.getVectorValue(V, Instance.Part);
2201 VectorValue = Builder.CreateInsertElement(VectorValue, ScalarInst,
2202 Builder.getInt32(Instance.Lane));
2203 VectorLoopValueMap.resetVectorValue(V, Instance.Part, VectorValue);
2204}
2205
2206Value *InnerLoopVectorizer::reverseVector(Value *Vec) {
2207 assert(Vec->getType()->isVectorTy() && "Invalid type")(static_cast <bool> (Vec->getType()->isVectorTy()
&& "Invalid type") ? void (0) : __assert_fail ("Vec->getType()->isVectorTy() && \"Invalid type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2207, __extension__ __PRETTY_FUNCTION__))
;
2208 SmallVector<Constant *, 8> ShuffleMask;
2209 for (unsigned i = 0; i < VF; ++i)
2210 ShuffleMask.push_back(Builder.getInt32(VF - i - 1));
2211
2212 return Builder.CreateShuffleVector(Vec, UndefValue::get(Vec->getType()),
2213 ConstantVector::get(ShuffleMask),
2214 "reverse");
2215}
2216
2217// Try to vectorize the interleave group that \p Instr belongs to.
2218//
2219// E.g. Translate following interleaved load group (factor = 3):
2220// for (i = 0; i < N; i+=3) {
2221// R = Pic[i]; // Member of index 0
2222// G = Pic[i+1]; // Member of index 1
2223// B = Pic[i+2]; // Member of index 2
2224// ... // do something to R, G, B
2225// }
2226// To:
2227// %wide.vec = load <12 x i32> ; Read 4 tuples of R,G,B
2228// %R.vec = shuffle %wide.vec, undef, <0, 3, 6, 9> ; R elements
2229// %G.vec = shuffle %wide.vec, undef, <1, 4, 7, 10> ; G elements
2230// %B.vec = shuffle %wide.vec, undef, <2, 5, 8, 11> ; B elements
2231//
2232// Or translate following interleaved store group (factor = 3):
2233// for (i = 0; i < N; i+=3) {
2234// ... do something to R, G, B
2235// Pic[i] = R; // Member of index 0
2236// Pic[i+1] = G; // Member of index 1
2237// Pic[i+2] = B; // Member of index 2
2238// }
2239// To:
2240// %R_G.vec = shuffle %R.vec, %G.vec, <0, 1, 2, ..., 7>
2241// %B_U.vec = shuffle %B.vec, undef, <0, 1, 2, 3, u, u, u, u>
2242// %interleaved.vec = shuffle %R_G.vec, %B_U.vec,
2243// <0, 4, 8, 1, 5, 9, 2, 6, 10, 3, 7, 11> ; Interleave R,G,B elements
2244// store <12 x i32> %interleaved.vec ; Write 4 tuples of R,G,B
2245void InnerLoopVectorizer::vectorizeInterleaveGroup(Instruction *Instr) {
2246 const InterleaveGroup *Group = Cost->getInterleavedAccessGroup(Instr);
2247 assert(Group && "Fail to get an interleaved access group.")(static_cast <bool> (Group && "Fail to get an interleaved access group."
) ? void (0) : __assert_fail ("Group && \"Fail to get an interleaved access group.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2247, __extension__ __PRETTY_FUNCTION__))
;
2248
2249 // Skip if current instruction is not the insert position.
2250 if (Instr != Group->getInsertPos())
2251 return;
2252
2253 const DataLayout &DL = Instr->getModule()->getDataLayout();
2254 Value *Ptr = getLoadStorePointerOperand(Instr);
2255
2256 // Prepare for the vector type of the interleaved load/store.
2257 Type *ScalarTy = getMemInstValueType(Instr);
2258 unsigned InterleaveFactor = Group->getFactor();
2259 Type *VecTy = VectorType::get(ScalarTy, InterleaveFactor * VF);
2260 Type *PtrTy = VecTy->getPointerTo(getMemInstAddressSpace(Instr));
2261
2262 // Prepare for the new pointers.
2263 setDebugLocFromInst(Builder, Ptr);
2264 SmallVector<Value *, 2> NewPtrs;
2265 unsigned Index = Group->getIndex(Instr);
2266
2267 // If the group is reverse, adjust the index to refer to the last vector lane
2268 // instead of the first. We adjust the index from the first vector lane,
2269 // rather than directly getting the pointer for lane VF - 1, because the
2270 // pointer operand of the interleaved access is supposed to be uniform. For
2271 // uniform instructions, we're only required to generate a value for the
2272 // first vector lane in each unroll iteration.
2273 if (Group->isReverse())
2274 Index += (VF - 1) * Group->getFactor();
2275
2276 bool InBounds = false;
2277 if (auto *gep = dyn_cast<GetElementPtrInst>(Ptr->stripPointerCasts()))
2278 InBounds = gep->isInBounds();
2279
2280 for (unsigned Part = 0; Part < UF; Part++) {
2281 Value *NewPtr = getOrCreateScalarValue(Ptr, {Part, 0});
2282
2283 // Notice current instruction could be any index. Need to adjust the address
2284 // to the member of index 0.
2285 //
2286 // E.g. a = A[i+1]; // Member of index 1 (Current instruction)
2287 // b = A[i]; // Member of index 0
2288 // Current pointer is pointed to A[i+1], adjust it to A[i].
2289 //
2290 // E.g. A[i+1] = a; // Member of index 1
2291 // A[i] = b; // Member of index 0
2292 // A[i+2] = c; // Member of index 2 (Current instruction)
2293 // Current pointer is pointed to A[i+2], adjust it to A[i].
2294 NewPtr = Builder.CreateGEP(NewPtr, Builder.getInt32(-Index));
2295 if (InBounds)
2296 cast<GetElementPtrInst>(NewPtr)->setIsInBounds(true);
2297
2298 // Cast to the vector pointer type.
2299 NewPtrs.push_back(Builder.CreateBitCast(NewPtr, PtrTy));
2300 }
2301
2302 setDebugLocFromInst(Builder, Instr);
2303 Value *UndefVec = UndefValue::get(VecTy);
2304
2305 // Vectorize the interleaved load group.
2306 if (isa<LoadInst>(Instr)) {
2307 // For each unroll part, create a wide load for the group.
2308 SmallVector<Value *, 2> NewLoads;
2309 for (unsigned Part = 0; Part < UF; Part++) {
2310 auto *NewLoad = Builder.CreateAlignedLoad(
2311 NewPtrs[Part], Group->getAlignment(), "wide.vec");
2312 Group->addMetadata(NewLoad);
2313 NewLoads.push_back(NewLoad);
2314 }
2315
2316 // For each member in the group, shuffle out the appropriate data from the
2317 // wide loads.
2318 for (unsigned I = 0; I < InterleaveFactor; ++I) {
2319 Instruction *Member = Group->getMember(I);
2320
2321 // Skip the gaps in the group.
2322 if (!Member)
2323 continue;
2324
2325 Constant *StrideMask = createStrideMask(Builder, I, InterleaveFactor, VF);
2326 for (unsigned Part = 0; Part < UF; Part++) {
2327 Value *StridedVec = Builder.CreateShuffleVector(
2328 NewLoads[Part], UndefVec, StrideMask, "strided.vec");
2329
2330 // If this member has different type, cast the result type.
2331 if (Member->getType() != ScalarTy) {
2332 VectorType *OtherVTy = VectorType::get(Member->getType(), VF);
2333 StridedVec = createBitOrPointerCast(StridedVec, OtherVTy, DL);
2334 }
2335
2336 if (Group->isReverse())
2337 StridedVec = reverseVector(StridedVec);
2338
2339 VectorLoopValueMap.setVectorValue(Member, Part, StridedVec);
2340 }
2341 }
2342 return;
2343 }
2344
2345 // The sub vector type for current instruction.
2346 VectorType *SubVT = VectorType::get(ScalarTy, VF);
2347
2348 // Vectorize the interleaved store group.
2349 for (unsigned Part = 0; Part < UF; Part++) {
2350 // Collect the stored vector from each member.
2351 SmallVector<Value *, 4> StoredVecs;
2352 for (unsigned i = 0; i < InterleaveFactor; i++) {
2353 // Interleaved store group doesn't allow a gap, so each index has a member
2354 Instruction *Member = Group->getMember(i);
2355 assert(Member && "Fail to get a member from an interleaved store group")(static_cast <bool> (Member && "Fail to get a member from an interleaved store group"
) ? void (0) : __assert_fail ("Member && \"Fail to get a member from an interleaved store group\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2355, __extension__ __PRETTY_FUNCTION__))
;
2356
2357 Value *StoredVec = getOrCreateVectorValue(
2358 cast<StoreInst>(Member)->getValueOperand(), Part);
2359 if (Group->isReverse())
2360 StoredVec = reverseVector(StoredVec);
2361
2362 // If this member has different type, cast it to a unified type.
2363
2364 if (StoredVec->getType() != SubVT)
2365 StoredVec = createBitOrPointerCast(StoredVec, SubVT, DL);
2366
2367 StoredVecs.push_back(StoredVec);
2368 }
2369
2370 // Concatenate all vectors into a wide vector.
2371 Value *WideVec = concatenateVectors(Builder, StoredVecs);
2372
2373 // Interleave the elements in the wide vector.
2374 Constant *IMask = createInterleaveMask(Builder, VF, InterleaveFactor);
2375 Value *IVec = Builder.CreateShuffleVector(WideVec, UndefVec, IMask,
2376 "interleaved.vec");
2377
2378 Instruction *NewStoreInstr =
2379 Builder.CreateAlignedStore(IVec, NewPtrs[Part], Group->getAlignment());
2380
2381 Group->addMetadata(NewStoreInstr);
2382 }
2383}
2384
2385void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr,
2386 VectorParts *BlockInMask) {
2387 // Attempt to issue a wide load.
2388 LoadInst *LI = dyn_cast<LoadInst>(Instr);
2389 StoreInst *SI = dyn_cast<StoreInst>(Instr);
2390
2391 assert((LI || SI) && "Invalid Load/Store instruction")(static_cast <bool> ((LI || SI) && "Invalid Load/Store instruction"
) ? void (0) : __assert_fail ("(LI || SI) && \"Invalid Load/Store instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2391, __extension__ __PRETTY_FUNCTION__))
;
2392
2393 LoopVectorizationCostModel::InstWidening Decision =
2394 Cost->getWideningDecision(Instr, VF);
2395 assert(Decision != LoopVectorizationCostModel::CM_Unknown &&(static_cast <bool> (Decision != LoopVectorizationCostModel
::CM_Unknown && "CM decision should be taken at this point"
) ? void (0) : __assert_fail ("Decision != LoopVectorizationCostModel::CM_Unknown && \"CM decision should be taken at this point\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2396, __extension__ __PRETTY_FUNCTION__))
2396 "CM decision should be taken at this point")(static_cast <bool> (Decision != LoopVectorizationCostModel
::CM_Unknown && "CM decision should be taken at this point"
) ? void (0) : __assert_fail ("Decision != LoopVectorizationCostModel::CM_Unknown && \"CM decision should be taken at this point\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2396, __extension__ __PRETTY_FUNCTION__))
;
2397 if (Decision == LoopVectorizationCostModel::CM_Interleave)
2398 return vectorizeInterleaveGroup(Instr);
2399
2400 Type *ScalarDataTy = getMemInstValueType(Instr);
2401 Type *DataTy = VectorType::get(ScalarDataTy, VF);
2402 Value *Ptr = getLoadStorePointerOperand(Instr);
2403 unsigned Alignment = getMemInstAlignment(Instr);
2404 // An alignment of 0 means target abi alignment. We need to use the scalar's
2405 // target abi alignment in such a case.
2406 const DataLayout &DL = Instr->getModule()->getDataLayout();
2407 if (!Alignment)
2408 Alignment = DL.getABITypeAlignment(ScalarDataTy);
2409 unsigned AddressSpace = getMemInstAddressSpace(Instr);
2410
2411 // Determine if the pointer operand of the access is either consecutive or
2412 // reverse consecutive.
2413 bool Reverse = (Decision == LoopVectorizationCostModel::CM_Widen_Reverse);
2414 bool ConsecutiveStride =
2415 Reverse || (Decision == LoopVectorizationCostModel::CM_Widen);
2416 bool CreateGatherScatter =
2417 (Decision == LoopVectorizationCostModel::CM_GatherScatter);
2418
2419 // Either Ptr feeds a vector load/store, or a vector GEP should feed a vector
2420 // gather/scatter. Otherwise Decision should have been to Scalarize.
2421 assert((ConsecutiveStride || CreateGatherScatter) &&(static_cast <bool> ((ConsecutiveStride || CreateGatherScatter
) && "The instruction should be scalarized") ? void (
0) : __assert_fail ("(ConsecutiveStride || CreateGatherScatter) && \"The instruction should be scalarized\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2422, __extension__ __PRETTY_FUNCTION__))
2422 "The instruction should be scalarized")(static_cast <bool> ((ConsecutiveStride || CreateGatherScatter
) && "The instruction should be scalarized") ? void (
0) : __assert_fail ("(ConsecutiveStride || CreateGatherScatter) && \"The instruction should be scalarized\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2422, __extension__ __PRETTY_FUNCTION__))
;
2423
2424 // Handle consecutive loads/stores.
2425 if (ConsecutiveStride)
2426 Ptr = getOrCreateScalarValue(Ptr, {0, 0});
2427
2428 VectorParts Mask;
2429 bool isMaskRequired = BlockInMask;
2430 if (isMaskRequired)
2431 Mask = *BlockInMask;
2432
2433 bool InBounds = false;
2434 if (auto *gep = dyn_cast<GetElementPtrInst>(
2435 getLoadStorePointerOperand(Instr)->stripPointerCasts()))
2436 InBounds = gep->isInBounds();
2437
2438 const auto CreateVecPtr = [&](unsigned Part, Value *Ptr) -> Value * {
2439 // Calculate the pointer for the specific unroll-part.
2440 GetElementPtrInst *PartPtr = nullptr;
2441
2442 if (Reverse) {
2443 // If the address is consecutive but reversed, then the
2444 // wide store needs to start at the last vector element.
2445 PartPtr = cast<GetElementPtrInst>(
2446 Builder.CreateGEP(Ptr, Builder.getInt32(-Part * VF)));
2447 PartPtr->setIsInBounds(InBounds);
2448 PartPtr = cast<GetElementPtrInst>(
2449 Builder.CreateGEP(PartPtr, Builder.getInt32(1 - VF)));
2450 PartPtr->setIsInBounds(InBounds);
2451 if (isMaskRequired) // Reverse of a null all-one mask is a null mask.
2452 Mask[Part] = reverseVector(Mask[Part]);
2453 } else {
2454 PartPtr = cast<GetElementPtrInst>(
2455 Builder.CreateGEP(Ptr, Builder.getInt32(Part * VF)));
2456 PartPtr->setIsInBounds(InBounds);
2457 }
2458
2459 return Builder.CreateBitCast(PartPtr, DataTy->getPointerTo(AddressSpace));
2460 };
2461
2462 // Handle Stores:
2463 if (SI) {
2464 setDebugLocFromInst(Builder, SI);
2465
2466 for (unsigned Part = 0; Part < UF; ++Part) {
2467 Instruction *NewSI = nullptr;
2468 Value *StoredVal = getOrCreateVectorValue(SI->getValueOperand(), Part);
2469 if (CreateGatherScatter) {
2470 Value *MaskPart = isMaskRequired ? Mask[Part] : nullptr;
2471 Value *VectorGep = getOrCreateVectorValue(Ptr, Part);
2472 NewSI = Builder.CreateMaskedScatter(StoredVal, VectorGep, Alignment,
2473 MaskPart);
2474 } else {
2475 if (Reverse) {
2476 // If we store to reverse consecutive memory locations, then we need
2477 // to reverse the order of elements in the stored value.
2478 StoredVal = reverseVector(StoredVal);
2479 // We don't want to update the value in the map as it might be used in
2480 // another expression. So don't call resetVectorValue(StoredVal).
2481 }
2482 auto *VecPtr = CreateVecPtr(Part, Ptr);
2483 if (isMaskRequired)
2484 NewSI = Builder.CreateMaskedStore(StoredVal, VecPtr, Alignment,
2485 Mask[Part]);
2486 else
2487 NewSI = Builder.CreateAlignedStore(StoredVal, VecPtr, Alignment);
2488 }
2489 addMetadata(NewSI, SI);
2490 }
2491 return;
2492 }
2493
2494 // Handle loads.
2495 assert(LI && "Must have a load instruction")(static_cast <bool> (LI && "Must have a load instruction"
) ? void (0) : __assert_fail ("LI && \"Must have a load instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2495, __extension__ __PRETTY_FUNCTION__))
;
2496 setDebugLocFromInst(Builder, LI);
2497 for (unsigned Part = 0; Part < UF; ++Part) {
2498 Value *NewLI;
2499 if (CreateGatherScatter) {
2500 Value *MaskPart = isMaskRequired ? Mask[Part] : nullptr;
2501 Value *VectorGep = getOrCreateVectorValue(Ptr, Part);
2502 NewLI = Builder.CreateMaskedGather(VectorGep, Alignment, MaskPart,
2503 nullptr, "wide.masked.gather");
2504 addMetadata(NewLI, LI);
2505 } else {
2506 auto *VecPtr = CreateVecPtr(Part, Ptr);
2507 if (isMaskRequired)
2508 NewLI = Builder.CreateMaskedLoad(VecPtr, Alignment, Mask[Part],
2509 UndefValue::get(DataTy),
2510 "wide.masked.load");
2511 else
2512 NewLI = Builder.CreateAlignedLoad(VecPtr, Alignment, "wide.load");
2513
2514 // Add metadata to the load, but setVectorValue to the reverse shuffle.
2515 addMetadata(NewLI, LI);
2516 if (Reverse)
2517 NewLI = reverseVector(NewLI);
2518 }
2519 VectorLoopValueMap.setVectorValue(Instr, Part, NewLI);
2520 }
2521}
2522
2523void InnerLoopVectorizer::scalarizeInstruction(Instruction *Instr,
2524 const VPIteration &Instance,
2525 bool IfPredicateInstr) {
2526 assert(!Instr->getType()->isAggregateType() && "Can't handle vectors")(static_cast <bool> (!Instr->getType()->isAggregateType
() && "Can't handle vectors") ? void (0) : __assert_fail
("!Instr->getType()->isAggregateType() && \"Can't handle vectors\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2526, __extension__ __PRETTY_FUNCTION__))
;
2527
2528 setDebugLocFromInst(Builder, Instr);
2529
2530 // Does this instruction return a value ?
2531 bool IsVoidRetTy = Instr->getType()->isVoidTy();
2532
2533 Instruction *Cloned = Instr->clone();
2534 if (!IsVoidRetTy)
2535 Cloned->setName(Instr->getName() + ".cloned");
2536
2537 // Replace the operands of the cloned instructions with their scalar
2538 // equivalents in the new loop.
2539 for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
2540 auto *NewOp = getOrCreateScalarValue(Instr->getOperand(op), Instance);
2541 Cloned->setOperand(op, NewOp);
2542 }
2543 addNewMetadata(Cloned, Instr);
2544
2545 // Place the cloned scalar in the new loop.
2546 Builder.Insert(Cloned);
2547
2548 // Add the cloned scalar to the scalar map entry.
2549 VectorLoopValueMap.setScalarValue(Instr, Instance, Cloned);
2550
2551 // If we just cloned a new assumption, add it the assumption cache.
2552 if (auto *II = dyn_cast<IntrinsicInst>(Cloned))
2553 if (II->getIntrinsicID() == Intrinsic::assume)
2554 AC->registerAssumption(II);
2555
2556 // End if-block.
2557 if (IfPredicateInstr)
2558 PredicatedInstructions.push_back(Cloned);
2559}
2560
2561PHINode *InnerLoopVectorizer::createInductionVariable(Loop *L, Value *Start,
2562 Value *End, Value *Step,
2563 Instruction *DL) {
2564 BasicBlock *Header = L->getHeader();
2565 BasicBlock *Latch = L->getLoopLatch();
2566 // As we're just creating this loop, it's possible no latch exists
2567 // yet. If so, use the header as this will be a single block loop.
2568 if (!Latch)
2569 Latch = Header;
2570
2571 IRBuilder<> Builder(&*Header->getFirstInsertionPt());
2572 Instruction *OldInst = getDebugLocFromInstOrOperands(OldInduction);
2573 setDebugLocFromInst(Builder, OldInst);
2574 auto *Induction = Builder.CreatePHI(Start->getType(), 2, "index");
2575
2576 Builder.SetInsertPoint(Latch->getTerminator());
2577 setDebugLocFromInst(Builder, OldInst);
2578
2579 // Create i+1 and fill the PHINode.
2580 Value *Next = Builder.CreateAdd(Induction, Step, "index.next");
2581 Induction->addIncoming(Start, L->getLoopPreheader());
2582 Induction->addIncoming(Next, Latch);
2583 // Create the compare.
2584 Value *ICmp = Builder.CreateICmpEQ(Next, End);
2585 Builder.CreateCondBr(ICmp, L->getExitBlock(), Header);
2586
2587 // Now we have two terminators. Remove the old one from the block.
2588 Latch->getTerminator()->eraseFromParent();
2589
2590 return Induction;
2591}
2592
2593Value *InnerLoopVectorizer::getOrCreateTripCount(Loop *L) {
2594 if (TripCount)
2595 return TripCount;
2596
2597 IRBuilder<> Builder(L->getLoopPreheader()->getTerminator());
2598 // Find the loop boundaries.
2599 ScalarEvolution *SE = PSE.getSE();
2600 const SCEV *BackedgeTakenCount = PSE.getBackedgeTakenCount();
2601 assert(BackedgeTakenCount != SE->getCouldNotCompute() &&(static_cast <bool> (BackedgeTakenCount != SE->getCouldNotCompute
() && "Invalid loop count") ? void (0) : __assert_fail
("BackedgeTakenCount != SE->getCouldNotCompute() && \"Invalid loop count\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2602, __extension__ __PRETTY_FUNCTION__))
2602 "Invalid loop count")(static_cast <bool> (BackedgeTakenCount != SE->getCouldNotCompute
() && "Invalid loop count") ? void (0) : __assert_fail
("BackedgeTakenCount != SE->getCouldNotCompute() && \"Invalid loop count\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2602, __extension__ __PRETTY_FUNCTION__))
;
2603
2604 Type *IdxTy = Legal->getWidestInductionType();
2605
2606 // The exit count might have the type of i64 while the phi is i32. This can
2607 // happen if we have an induction variable that is sign extended before the
2608 // compare. The only way that we get a backedge taken count is that the
2609 // induction variable was signed and as such will not overflow. In such a case
2610 // truncation is legal.
2611 if (BackedgeTakenCount->getType()->getPrimitiveSizeInBits() >
2612 IdxTy->getPrimitiveSizeInBits())
2613 BackedgeTakenCount = SE->getTruncateOrNoop(BackedgeTakenCount, IdxTy);
2614 BackedgeTakenCount = SE->getNoopOrZeroExtend(BackedgeTakenCount, IdxTy);
2615
2616 // Get the total trip count from the count by adding 1.
2617 const SCEV *ExitCount = SE->getAddExpr(
2618 BackedgeTakenCount, SE->getOne(BackedgeTakenCount->getType()));
2619
2620 const DataLayout &DL = L->getHeader()->getModule()->getDataLayout();
2621
2622 // Expand the trip count and place the new instructions in the preheader.
2623 // Notice that the pre-header does not change, only the loop body.
2624 SCEVExpander Exp(*SE, DL, "induction");
2625
2626 // Count holds the overall loop count (N).
2627 TripCount = Exp.expandCodeFor(ExitCount, ExitCount->getType(),
2628 L->getLoopPreheader()->getTerminator());
2629
2630 if (TripCount->getType()->isPointerTy())
2631 TripCount =
2632 CastInst::CreatePointerCast(TripCount, IdxTy, "exitcount.ptrcnt.to.int",
2633 L->getLoopPreheader()->getTerminator());
2634
2635 return TripCount;
2636}
2637
2638Value *InnerLoopVectorizer::getOrCreateVectorTripCount(Loop *L) {
2639 if (VectorTripCount)
2640 return VectorTripCount;
2641
2642 Value *TC = getOrCreateTripCount(L);
2643 IRBuilder<> Builder(L->getLoopPreheader()->getTerminator());
2644
2645 // Now we need to generate the expression for the part of the loop that the
2646 // vectorized body will execute. This is equal to N - (N % Step) if scalar
2647 // iterations are not required for correctness, or N - Step, otherwise. Step
2648 // is equal to the vectorization factor (number of SIMD elements) times the
2649 // unroll factor (number of SIMD instructions).
2650 Constant *Step = ConstantInt::get(TC->getType(), VF * UF);
2651 Value *R = Builder.CreateURem(TC, Step, "n.mod.vf");
2652
2653 // If there is a non-reversed interleaved group that may speculatively access
2654 // memory out-of-bounds, we need to ensure that there will be at least one
2655 // iteration of the scalar epilogue loop. Thus, if the step evenly divides
2656 // the trip count, we set the remainder to be equal to the step. If the step
2657 // does not evenly divide the trip count, no adjustment is necessary since
2658 // there will already be scalar iterations. Note that the minimum iterations
2659 // check ensures that N >= Step.
2660 if (VF > 1 && Cost->requiresScalarEpilogue()) {
2661 auto *IsZero = Builder.CreateICmpEQ(R, ConstantInt::get(R->getType(), 0));
2662 R = Builder.CreateSelect(IsZero, Step, R);
2663 }
2664
2665 VectorTripCount = Builder.CreateSub(TC, R, "n.vec");
2666
2667 return VectorTripCount;
2668}
2669
2670Value *InnerLoopVectorizer::createBitOrPointerCast(Value *V, VectorType *DstVTy,
2671 const DataLayout &DL) {
2672 // Verify that V is a vector type with same number of elements as DstVTy.
2673 unsigned VF = DstVTy->getNumElements();
2674 VectorType *SrcVecTy = cast<VectorType>(V->getType());
2675 assert((VF == SrcVecTy->getNumElements()) && "Vector dimensions do not match")(static_cast <bool> ((VF == SrcVecTy->getNumElements
()) && "Vector dimensions do not match") ? void (0) :
__assert_fail ("(VF == SrcVecTy->getNumElements()) && \"Vector dimensions do not match\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2675, __extension__ __PRETTY_FUNCTION__))
;
2676 Type *SrcElemTy = SrcVecTy->getElementType();
2677 Type *DstElemTy = DstVTy->getElementType();
2678 assert((DL.getTypeSizeInBits(SrcElemTy) == DL.getTypeSizeInBits(DstElemTy)) &&(static_cast <bool> ((DL.getTypeSizeInBits(SrcElemTy) ==
DL.getTypeSizeInBits(DstElemTy)) && "Vector elements must have same size"
) ? void (0) : __assert_fail ("(DL.getTypeSizeInBits(SrcElemTy) == DL.getTypeSizeInBits(DstElemTy)) && \"Vector elements must have same size\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2679, __extension__ __PRETTY_FUNCTION__))
2679 "Vector elements must have same size")(static_cast <bool> ((DL.getTypeSizeInBits(SrcElemTy) ==
DL.getTypeSizeInBits(DstElemTy)) && "Vector elements must have same size"
) ? void (0) : __assert_fail ("(DL.getTypeSizeInBits(SrcElemTy) == DL.getTypeSizeInBits(DstElemTy)) && \"Vector elements must have same size\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2679, __extension__ __PRETTY_FUNCTION__))
;
2680
2681 // Do a direct cast if element types are castable.
2682 if (CastInst::isBitOrNoopPointerCastable(SrcElemTy, DstElemTy, DL)) {
2683 return Builder.CreateBitOrPointerCast(V, DstVTy);
2684 }
2685 // V cannot be directly casted to desired vector type.
2686 // May happen when V is a floating point vector but DstVTy is a vector of
2687 // pointers or vice-versa. Handle this using a two-step bitcast using an
2688 // intermediate Integer type for the bitcast i.e. Ptr <-> Int <-> Float.
2689 assert((DstElemTy->isPointerTy() != SrcElemTy->isPointerTy()) &&(static_cast <bool> ((DstElemTy->isPointerTy() != SrcElemTy
->isPointerTy()) && "Only one type should be a pointer type"
) ? void (0) : __assert_fail ("(DstElemTy->isPointerTy() != SrcElemTy->isPointerTy()) && \"Only one type should be a pointer type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2690, __extension__ __PRETTY_FUNCTION__))
2690 "Only one type should be a pointer type")(static_cast <bool> ((DstElemTy->isPointerTy() != SrcElemTy
->isPointerTy()) && "Only one type should be a pointer type"
) ? void (0) : __assert_fail ("(DstElemTy->isPointerTy() != SrcElemTy->isPointerTy()) && \"Only one type should be a pointer type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2690, __extension__ __PRETTY_FUNCTION__))
;
2691 assert((DstElemTy->isFloatingPointTy() != SrcElemTy->isFloatingPointTy()) &&(static_cast <bool> ((DstElemTy->isFloatingPointTy()
!= SrcElemTy->isFloatingPointTy()) && "Only one type should be a floating point type"
) ? void (0) : __assert_fail ("(DstElemTy->isFloatingPointTy() != SrcElemTy->isFloatingPointTy()) && \"Only one type should be a floating point type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2692, __extension__ __PRETTY_FUNCTION__))
2692 "Only one type should be a floating point type")(static_cast <bool> ((DstElemTy->isFloatingPointTy()
!= SrcElemTy->isFloatingPointTy()) && "Only one type should be a floating point type"
) ? void (0) : __assert_fail ("(DstElemTy->isFloatingPointTy() != SrcElemTy->isFloatingPointTy()) && \"Only one type should be a floating point type\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2692, __extension__ __PRETTY_FUNCTION__))
;
2693 Type *IntTy =
2694 IntegerType::getIntNTy(V->getContext(), DL.getTypeSizeInBits(SrcElemTy));
2695 VectorType *VecIntTy = VectorType::get(IntTy, VF);
2696 Value *CastVal = Builder.CreateBitOrPointerCast(V, VecIntTy);
2697 return Builder.CreateBitOrPointerCast(CastVal, DstVTy);
2698}
2699
2700void InnerLoopVectorizer::emitMinimumIterationCountCheck(Loop *L,
2701 BasicBlock *Bypass) {
2702 Value *Count = getOrCreateTripCount(L);
2703 BasicBlock *BB = L->getLoopPreheader();
2704 IRBuilder<> Builder(BB->getTerminator());
2705
2706 // Generate code to check if the loop's trip count is less than VF * UF, or
2707 // equal to it in case a scalar epilogue is required; this implies that the
2708 // vector trip count is zero. This check also covers the case where adding one
2709 // to the backedge-taken count overflowed leading to an incorrect trip count
2710 // of zero. In this case we will also jump to the scalar loop.
2711 auto P = Cost->requiresScalarEpilogue() ? ICmpInst::ICMP_ULE
2712 : ICmpInst::ICMP_ULT;
2713 Value *CheckMinIters = Builder.CreateICmp(
2714 P, Count, ConstantInt::get(Count->getType(), VF * UF), "min.iters.check");
2715
2716 BasicBlock *NewBB = BB->splitBasicBlock(BB->getTerminator(), "vector.ph");
2717 // Update dominator tree immediately if the generated block is a
2718 // LoopBypassBlock because SCEV expansions to generate loop bypass
2719 // checks may query it before the current function is finished.
2720 DT->addNewBlock(NewBB, BB);
2721 if (L->getParentLoop())
2722 L->getParentLoop()->addBasicBlockToLoop(NewBB, *LI);
2723 ReplaceInstWithInst(BB->getTerminator(),
2724 BranchInst::Create(Bypass, NewBB, CheckMinIters));
2725 LoopBypassBlocks.push_back(BB);
2726}
2727
2728void InnerLoopVectorizer::emitSCEVChecks(Loop *L, BasicBlock *Bypass) {
2729 BasicBlock *BB = L->getLoopPreheader();
2730
2731 // Generate the code to check that the SCEV assumptions that we made.
2732 // We want the new basic block to start at the first instruction in a
2733 // sequence of instructions that form a check.
2734 SCEVExpander Exp(*PSE.getSE(), Bypass->getModule()->getDataLayout(),
2735 "scev.check");
2736 Value *SCEVCheck =
2737 Exp.expandCodeForPredicate(&PSE.getUnionPredicate(), BB->getTerminator());
2738
2739 if (auto *C = dyn_cast<ConstantInt>(SCEVCheck))
2740 if (C->isZero())
2741 return;
2742
2743 // Create a new block containing the stride check.
2744 BB->setName("vector.scevcheck");
2745 auto *NewBB = BB->splitBasicBlock(BB->getTerminator(), "vector.ph");
2746 // Update dominator tree immediately if the generated block is a
2747 // LoopBypassBlock because SCEV expansions to generate loop bypass
2748 // checks may query it before the current function is finished.
2749 DT->addNewBlock(NewBB, BB);
2750 if (L->getParentLoop())
2751 L->getParentLoop()->addBasicBlockToLoop(NewBB, *LI);
2752 ReplaceInstWithInst(BB->getTerminator(),
2753 BranchInst::Create(Bypass, NewBB, SCEVCheck));
2754 LoopBypassBlocks.push_back(BB);
2755 AddedSafetyChecks = true;
2756}
2757
2758void InnerLoopVectorizer::emitMemRuntimeChecks(Loop *L, BasicBlock *Bypass) {
2759 BasicBlock *BB = L->getLoopPreheader();
2760
2761 // Generate the code that checks in runtime if arrays overlap. We put the
2762 // checks into a separate block to make the more common case of few elements
2763 // faster.
2764 Instruction *FirstCheckInst;
2765 Instruction *MemRuntimeCheck;
2766 std::tie(FirstCheckInst, MemRuntimeCheck) =
2767 Legal->getLAI()->addRuntimeChecks(BB->getTerminator());
2768 if (!MemRuntimeCheck)
2769 return;
2770
2771 // Create a new block containing the memory check.
2772 BB->setName("vector.memcheck");
2773 auto *NewBB = BB->splitBasicBlock(BB->getTerminator(), "vector.ph");
2774 // Update dominator tree immediately if the generated block is a
2775 // LoopBypassBlock because SCEV expansions to generate loop bypass
2776 // checks may query it before the current function is finished.
2777 DT->addNewBlock(NewBB, BB);
2778 if (L->getParentLoop())
2779 L->getParentLoop()->addBasicBlockToLoop(NewBB, *LI);
2780 ReplaceInstWithInst(BB->getTerminator(),
2781 BranchInst::Create(Bypass, NewBB, MemRuntimeCheck));
2782 LoopBypassBlocks.push_back(BB);
2783 AddedSafetyChecks = true;
2784
2785 // We currently don't use LoopVersioning for the actual loop cloning but we
2786 // still use it to add the noalias metadata.
2787 LVer = llvm::make_unique<LoopVersioning>(*Legal->getLAI(), OrigLoop, LI, DT,
2788 PSE.getSE());
2789 LVer->prepareNoAliasMetadata();
2790}
2791
2792BasicBlock *InnerLoopVectorizer::createVectorizedLoopSkeleton() {
2793 /*
2794 In this function we generate a new loop. The new loop will contain
2795 the vectorized instructions while the old loop will continue to run the
2796 scalar remainder.
2797
2798 [ ] <-- loop iteration number check.
2799 / |
2800 / v
2801 | [ ] <-- vector loop bypass (may consist of multiple blocks).
2802 | / |
2803 | / v
2804 || [ ] <-- vector pre header.
2805 |/ |
2806 | v
2807 | [ ] \
2808 | [ ]_| <-- vector loop.
2809 | |
2810 | v
2811 | -[ ] <--- middle-block.
2812 | / |
2813 | / v
2814 -|- >[ ] <--- new preheader.
2815 | |
2816 | v
2817 | [ ] \
2818 | [ ]_| <-- old scalar loop to handle remainder.
2819 \ |
2820 \ v
2821 >[ ] <-- exit block.
2822 ...
2823 */
2824
2825 BasicBlock *OldBasicBlock = OrigLoop->getHeader();
2826 BasicBlock *VectorPH = OrigLoop->getLoopPreheader();
2827 BasicBlock *ExitBlock = OrigLoop->getExitBlock();
2828 assert(VectorPH && "Invalid loop structure")(static_cast <bool> (VectorPH && "Invalid loop structure"
) ? void (0) : __assert_fail ("VectorPH && \"Invalid loop structure\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2828, __extension__ __PRETTY_FUNCTION__))
;
2829 assert(ExitBlock && "Must have an exit block")(static_cast <bool> (ExitBlock && "Must have an exit block"
) ? void (0) : __assert_fail ("ExitBlock && \"Must have an exit block\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2829, __extension__ __PRETTY_FUNCTION__))
;
2830
2831 // Some loops have a single integer induction variable, while other loops
2832 // don't. One example is c++ iterators that often have multiple pointer
2833 // induction variables. In the code below we also support a case where we
2834 // don't have a single induction variable.
2835 //
2836 // We try to obtain an induction variable from the original loop as hard
2837 // as possible. However if we don't find one that:
2838 // - is an integer
2839 // - counts from zero, stepping by one
2840 // - is the size of the widest induction variable type
2841 // then we create a new one.
2842 OldInduction = Legal->getPrimaryInduction();
2843 Type *IdxTy = Legal->getWidestInductionType();
2844
2845 // Split the single block loop into the two loop structure described above.
2846 BasicBlock *VecBody =
2847 VectorPH->splitBasicBlock(VectorPH->getTerminator(), "vector.body");
2848 BasicBlock *MiddleBlock =
2849 VecBody->splitBasicBlock(VecBody->getTerminator(), "middle.block");
2850 BasicBlock *ScalarPH =
2851 MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), "scalar.ph");
2852
2853 // Create and register the new vector loop.
2854 Loop *Lp = LI->AllocateLoop();
2855 Loop *ParentLoop = OrigLoop->getParentLoop();
2856
2857 // Insert the new loop into the loop nest and register the new basic blocks
2858 // before calling any utilities such as SCEV that require valid LoopInfo.
2859 if (ParentLoop) {
2860 ParentLoop->addChildLoop(Lp);
2861 ParentLoop->addBasicBlockToLoop(ScalarPH, *LI);
2862 ParentLoop->addBasicBlockToLoop(MiddleBlock, *LI);
2863 } else {
2864 LI->addTopLevelLoop(Lp);
2865 }
2866 Lp->addBasicBlockToLoop(VecBody, *LI);
2867
2868 // Find the loop boundaries.
2869 Value *Count = getOrCreateTripCount(Lp);
2870
2871 Value *StartIdx = ConstantInt::get(IdxTy, 0);
2872
2873 // Now, compare the new count to zero. If it is zero skip the vector loop and
2874 // jump to the scalar loop. This check also covers the case where the
2875 // backedge-taken count is uint##_max: adding one to it will overflow leading
2876 // to an incorrect trip count of zero. In this (rare) case we will also jump
2877 // to the scalar loop.
2878 emitMinimumIterationCountCheck(Lp, ScalarPH);
2879
2880 // Generate the code to check any assumptions that we've made for SCEV
2881 // expressions.
2882 emitSCEVChecks(Lp, ScalarPH);
2883
2884 // Generate the code that checks in runtime if arrays overlap. We put the
2885 // checks into a separate block to make the more common case of few elements
2886 // faster.
2887 emitMemRuntimeChecks(Lp, ScalarPH);
2888
2889 // Generate the induction variable.
2890 // The loop step is equal to the vectorization factor (num of SIMD elements)
2891 // times the unroll factor (num of SIMD instructions).
2892 Value *CountRoundDown = getOrCreateVectorTripCount(Lp);
2893 Constant *Step = ConstantInt::get(IdxTy, VF * UF);
2894 Induction =
2895 createInductionVariable(Lp, StartIdx, CountRoundDown, Step,
2896 getDebugLocFromInstOrOperands(OldInduction));
2897
2898 // We are going to resume the execution of the scalar loop.
2899 // Go over all of the induction variables that we found and fix the
2900 // PHIs that are left in the scalar version of the loop.
2901 // The starting values of PHI nodes depend on the counter of the last
2902 // iteration in the vectorized loop.
2903 // If we come from a bypass edge then we need to start from the original
2904 // start value.
2905
2906 // This variable saves the new starting index for the scalar loop. It is used
2907 // to test if there are any tail iterations left once the vector loop has
2908 // completed.
2909 LoopVectorizationLegality::InductionList *List = Legal->getInductionVars();
2910 for (auto &InductionEntry : *List) {
2911 PHINode *OrigPhi = InductionEntry.first;
2912 InductionDescriptor II = InductionEntry.second;
2913
2914 // Create phi nodes to merge from the backedge-taken check block.
2915 PHINode *BCResumeVal = PHINode::Create(
2916 OrigPhi->getType(), 3, "bc.resume.val", ScalarPH->getTerminator());
2917 // Copy original phi DL over to the new one.
2918 BCResumeVal->setDebugLoc(OrigPhi->getDebugLoc());
2919 Value *&EndValue = IVEndValues[OrigPhi];
2920 if (OrigPhi == OldInduction) {
2921 // We know what the end value is.
2922 EndValue = CountRoundDown;
2923 } else {
2924 IRBuilder<> B(Lp->getLoopPreheader()->getTerminator());
2925 Type *StepType = II.getStep()->getType();
2926 Instruction::CastOps CastOp =
2927 CastInst::getCastOpcode(CountRoundDown, true, StepType, true);
2928 Value *CRD = B.CreateCast(CastOp, CountRoundDown, StepType, "cast.crd");
2929 const DataLayout &DL = OrigLoop->getHeader()->getModule()->getDataLayout();
2930 EndValue = II.transform(B, CRD, PSE.getSE(), DL);
2931 EndValue->setName("ind.end");
2932 }
2933
2934 // The new PHI merges the original incoming value, in case of a bypass,
2935 // or the value at the end of the vectorized loop.
2936 BCResumeVal->addIncoming(EndValue, MiddleBlock);
2937
2938 // Fix the scalar body counter (PHI node).
2939 unsigned BlockIdx = OrigPhi->getBasicBlockIndex(ScalarPH);
2940
2941 // The old induction's phi node in the scalar body needs the truncated
2942 // value.
2943 for (BasicBlock *BB : LoopBypassBlocks)
2944 BCResumeVal->addIncoming(II.getStartValue(), BB);
2945 OrigPhi->setIncomingValue(BlockIdx, BCResumeVal);
2946 }
2947
2948 // Add a check in the middle block to see if we have completed
2949 // all of the iterations in the first vector loop.
2950 // If (N - N%VF) == N, then we *don't* need to run the remainder.
2951 Value *CmpN =
2952 CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, Count,
2953 CountRoundDown, "cmp.n", MiddleBlock->getTerminator());
2954 ReplaceInstWithInst(MiddleBlock->getTerminator(),
2955 BranchInst::Create(ExitBlock, ScalarPH, CmpN));
2956
2957 // Get ready to start creating new instructions into the vectorized body.
2958 Builder.SetInsertPoint(&*VecBody->getFirstInsertionPt());
2959
2960 // Save the state.
2961 LoopVectorPreHeader = Lp->getLoopPreheader();
2962 LoopScalarPreHeader = ScalarPH;
2963 LoopMiddleBlock = MiddleBlock;
2964 LoopExitBlock = ExitBlock;
2965 LoopVectorBody = VecBody;
2966 LoopScalarBody = OldBasicBlock;
2967
2968 // Keep all loop hints from the original loop on the vector loop (we'll
2969 // replace the vectorizer-specific hints below).
2970 if (MDNode *LID = OrigLoop->getLoopID())
2971 Lp->setLoopID(LID);
2972
2973 LoopVectorizeHints Hints(Lp, true, *ORE);
2974 Hints.setAlreadyVectorized();
2975
2976 return LoopVectorPreHeader;
2977}
2978
2979// Fix up external users of the induction variable. At this point, we are
2980// in LCSSA form, with all external PHIs that use the IV having one input value,
2981// coming from the remainder loop. We need those PHIs to also have a correct
2982// value for the IV when arriving directly from the middle block.
2983void InnerLoopVectorizer::fixupIVUsers(PHINode *OrigPhi,
2984 const InductionDescriptor &II,
2985 Value *CountRoundDown, Value *EndValue,
2986 BasicBlock *MiddleBlock) {
2987 // There are two kinds of external IV usages - those that use the value
2988 // computed in the last iteration (the PHI) and those that use the penultimate
2989 // value (the value that feeds into the phi from the loop latch).
2990 // We allow both, but they, obviously, have different values.
2991
2992 assert(OrigLoop->getExitBlock() && "Expected a single exit block")(static_cast <bool> (OrigLoop->getExitBlock() &&
"Expected a single exit block") ? void (0) : __assert_fail (
"OrigLoop->getExitBlock() && \"Expected a single exit block\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2992, __extension__ __PRETTY_FUNCTION__))
;
2993
2994 DenseMap<Value *, Value *> MissingVals;
2995
2996 // An external user of the last iteration's value should see the value that
2997 // the remainder loop uses to initialize its own IV.
2998 Value *PostInc = OrigPhi->getIncomingValueForBlock(OrigLoop->getLoopLatch());
2999 for (User *U : PostInc->users()) {
3000 Instruction *UI = cast<Instruction>(U);
3001 if (!OrigLoop->contains(UI)) {
3002 assert(isa<PHINode>(UI) && "Expected LCSSA form")(static_cast <bool> (isa<PHINode>(UI) && "Expected LCSSA form"
) ? void (0) : __assert_fail ("isa<PHINode>(UI) && \"Expected LCSSA form\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3002, __extension__ __PRETTY_FUNCTION__))
;
3003 MissingVals[UI] = EndValue;
3004 }
3005 }
3006
3007 // An external user of the penultimate value need to see EndValue - Step.
3008 // The simplest way to get this is to recompute it from the constituent SCEVs,
3009 // that is Start + (Step * (CRD - 1)).
3010 for (User *U : OrigPhi->users()) {
3011 auto *UI = cast<Instruction>(U);
3012 if (!OrigLoop->contains(UI)) {
3013 const DataLayout &DL =
3014 OrigLoop->getHeader()->getModule()->getDataLayout();
3015 assert(isa<PHINode>(UI) && "Expected LCSSA form")(static_cast <bool> (isa<PHINode>(UI) && "Expected LCSSA form"
) ? void (0) : __assert_fail ("isa<PHINode>(UI) && \"Expected LCSSA form\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3015, __extension__ __PRETTY_FUNCTION__))
;
3016
3017 IRBuilder<> B(MiddleBlock->getTerminator());
3018 Value *CountMinusOne = B.CreateSub(
3019 CountRoundDown, ConstantInt::get(CountRoundDown->getType(), 1));
3020 Value *CMO =
3021 !II.getStep()->getType()->isIntegerTy()
3022 ? B.CreateCast(Instruction::SIToFP, CountMinusOne,
3023 II.getStep()->getType())
3024 : B.CreateSExtOrTrunc(CountMinusOne, II.getStep()->getType());
3025 CMO->setName("cast.cmo");
3026 Value *Escape = II.transform(B, CMO, PSE.getSE(), DL);
3027 Escape->setName("ind.escape");
3028 MissingVals[UI] = Escape;
3029 }
3030 }
3031
3032 for (auto &I : MissingVals) {
3033 PHINode *PHI = cast<PHINode>(I.first);
3034 // One corner case we have to handle is two IVs "chasing" each-other,
3035 // that is %IV2 = phi [...], [ %IV1, %latch ]
3036 // In this case, if IV1 has an external use, we need to avoid adding both
3037 // "last value of IV1" and "penultimate value of IV2". So, verify that we
3038 // don't already have an incoming value for the middle block.
3039 if (PHI->getBasicBlockIndex(MiddleBlock) == -1)
3040 PHI->addIncoming(I.second, MiddleBlock);
3041 }
3042}
3043
3044namespace {
3045
3046struct CSEDenseMapInfo {
3047 static bool canHandle(const Instruction *I) {
3048 return isa<InsertElementInst>(I) || isa<ExtractElementInst>(I) ||
3049 isa<ShuffleVectorInst>(I) || isa<GetElementPtrInst>(I);
3050 }
3051
3052 static inline Instruction *getEmptyKey() {
3053 return DenseMapInfo<Instruction *>::getEmptyKey();
3054 }
3055
3056 static inline Instruction *getTombstoneKey() {
3057 return DenseMapInfo<Instruction *>::getTombstoneKey();
3058 }
3059
3060 static unsigned getHashValue(const Instruction *I) {
3061 assert(canHandle(I) && "Unknown instruction!")(static_cast <bool> (canHandle(I) && "Unknown instruction!"
) ? void (0) : __assert_fail ("canHandle(I) && \"Unknown instruction!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3061, __extension__ __PRETTY_FUNCTION__))
;
3062 return hash_combine(I->getOpcode(), hash_combine_range(I->value_op_begin(),
3063 I->value_op_end()));
3064 }
3065
3066 static bool isEqual(const Instruction *LHS, const Instruction *RHS) {
3067 if (LHS == getEmptyKey() || RHS == getEmptyKey() ||
3068 LHS == getTombstoneKey() || RHS == getTombstoneKey())
3069 return LHS == RHS;
3070 return LHS->isIdenticalTo(RHS);
3071 }
3072};
3073
3074} // end anonymous namespace
3075
3076///Perform cse of induction variable instructions.
3077static void cse(BasicBlock *BB) {
3078 // Perform simple cse.
3079 SmallDenseMap<Instruction *, Instruction *, 4, CSEDenseMapInfo> CSEMap;
3080 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) {
3081 Instruction *In = &*I++;
3082
3083 if (!CSEDenseMapInfo::canHandle(In))
3084 continue;
3085
3086 // Check if we can replace this instruction with any of the
3087 // visited instructions.
3088 if (Instruction *V = CSEMap.lookup(In)) {
3089 In->replaceAllUsesWith(V);
3090 In->eraseFromParent();
3091 continue;
3092 }
3093
3094 CSEMap[In] = In;
3095 }
3096}
3097
3098/// Estimate the overhead of scalarizing an instruction. This is a
3099/// convenience wrapper for the type-based getScalarizationOverhead API.
3100static unsigned getScalarizationOverhead(Instruction *I, unsigned VF,
3101 const TargetTransformInfo &TTI) {
3102 if (VF == 1)
3103 return 0;
3104
3105 unsigned Cost = 0;
3106 Type *RetTy = ToVectorTy(I->getType(), VF);
3107 if (!RetTy->isVoidTy() &&
3108 (!isa<LoadInst>(I) ||
3109 !TTI.supportsEfficientVectorElementLoadStore()))
3110 Cost += TTI.getScalarizationOverhead(RetTy, true, false);
3111
3112 if (CallInst *CI = dyn_cast<CallInst>(I)) {
3113 SmallVector<const Value *, 4> Operands(CI->arg_operands());
3114 Cost += TTI.getOperandsScalarizationOverhead(Operands, VF);
3115 }
3116 else if (!isa<StoreInst>(I) ||
3117 !TTI.supportsEfficientVectorElementLoadStore()) {
3118 SmallVector<const Value *, 4> Operands(I->operand_values());
3119 Cost += TTI.getOperandsScalarizationOverhead(Operands, VF);
3120 }
3121
3122 return Cost;
3123}
3124
3125// Estimate cost of a call instruction CI if it were vectorized with factor VF.
3126// Return the cost of the instruction, including scalarization overhead if it's
3127// needed. The flag NeedToScalarize shows if the call needs to be scalarized -
3128// i.e. either vector version isn't available, or is too expensive.
3129static unsigned getVectorCallCost(CallInst *CI, unsigned VF,
3130 const TargetTransformInfo &TTI,
3131 const TargetLibraryInfo *TLI,
3132 bool &NeedToScalarize) {
3133 Function *F = CI->getCalledFunction();
3134 StringRef FnName = CI->getCalledFunction()->getName();
3135 Type *ScalarRetTy = CI->getType();
3136 SmallVector<Type *, 4> Tys, ScalarTys;
3137 for (auto &ArgOp : CI->arg_operands())
3138 ScalarTys.push_back(ArgOp->getType());
3139
3140 // Estimate cost of scalarized vector call. The source operands are assumed
3141 // to be vectors, so we need to extract individual elements from there,
3142 // execute VF scalar calls, and then gather the result into the vector return
3143 // value.
3144 unsigned ScalarCallCost = TTI.getCallInstrCost(F, ScalarRetTy, ScalarTys);
3145 if (VF == 1)
3146 return ScalarCallCost;
3147
3148 // Compute corresponding vector type for return value and arguments.
3149 Type *RetTy = ToVectorTy(ScalarRetTy, VF);
3150 for (Type *ScalarTy : ScalarTys)
3151 Tys.push_back(ToVectorTy(ScalarTy, VF));
3152
3153 // Compute costs of unpacking argument values for the scalar calls and
3154 // packing the return values to a vector.
3155 unsigned ScalarizationCost = getScalarizationOverhead(CI, VF, TTI);
3156
3157 unsigned Cost = ScalarCallCost * VF + ScalarizationCost;
3158
3159 // If we can't emit a vector call for this function, then the currently found
3160 // cost is the cost we need to return.
3161 NeedToScalarize = true;
3162 if (!TLI || !TLI->isFunctionVectorizable(FnName, VF) || CI->isNoBuiltin())
3163 return Cost;
3164
3165 // If the corresponding vector cost is cheaper, return its cost.
3166 unsigned VectorCallCost = TTI.getCallInstrCost(nullptr, RetTy, Tys);
3167 if (VectorCallCost < Cost) {
3168 NeedToScalarize = false;
3169 return VectorCallCost;
3170 }
3171 return Cost;
3172}
3173
3174// Estimate cost of an intrinsic call instruction CI if it were vectorized with
3175// factor VF. Return the cost of the instruction, including scalarization
3176// overhead if it's needed.
3177static unsigned getVectorIntrinsicCost(CallInst *CI, unsigned VF,
3178 const TargetTransformInfo &TTI,
3179 const TargetLibraryInfo *TLI) {
3180 Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
3181 assert(ID && "Expected intrinsic call!")(static_cast <bool> (ID && "Expected intrinsic call!"
) ? void (0) : __assert_fail ("ID && \"Expected intrinsic call!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3181, __extension__ __PRETTY_FUNCTION__))
;
3182
3183 FastMathFlags FMF;
3184 if (auto *FPMO = dyn_cast<FPMathOperator>(CI))
3185 FMF = FPMO->getFastMathFlags();
3186
3187 SmallVector<Value *, 4> Operands(CI->arg_operands());
3188 return TTI.getIntrinsicInstrCost(ID, CI->getType(), Operands, FMF, VF);
3189}
3190
3191static Type *smallestIntegerVectorType(Type *T1, Type *T2) {
3192 auto *I1 = cast<IntegerType>(T1->getVectorElementType());
3193 auto *I2 = cast<IntegerType>(T2->getVectorElementType());
3194 return I1->getBitWidth() < I2->getBitWidth() ? T1 : T2;
3195}
3196static Type *largestIntegerVectorType(Type *T1, Type *T2) {
3197 auto *I1 = cast<IntegerType>(T1->getVectorElementType());
3198 auto *I2 = cast<IntegerType>(T2->getVectorElementType());
3199 return I1->getBitWidth() > I2->getBitWidth() ? T1 : T2;
3200}
3201
3202void InnerLoopVectorizer::truncateToMinimalBitwidths() {
3203 // For every instruction `I` in MinBWs, truncate the operands, create a
3204 // truncated version of `I` and reextend its result. InstCombine runs
3205 // later and will remove any ext/trunc pairs.
3206 SmallPtrSet<Value *, 4> Erased;
3207 for (const auto &KV : Cost->getMinimalBitwidths()) {
3208 // If the value wasn't vectorized, we must maintain the original scalar
3209 // type. The absence of the value from VectorLoopValueMap indicates that it
3210 // wasn't vectorized.
3211 if (!VectorLoopValueMap.hasAnyVectorValue(KV.first))
3212 continue;
3213 for (unsigned Part = 0; Part < UF; ++Part) {
3214 Value *I = getOrCreateVectorValue(KV.first, Part);
3215 if (Erased.count(I) || I->use_empty() || !isa<Instruction>(I))
3216 continue;
3217 Type *OriginalTy = I->getType();
3218 Type *ScalarTruncatedTy =
3219 IntegerType::get(OriginalTy->getContext(), KV.second);
3220 Type *TruncatedTy = VectorType::get(ScalarTruncatedTy,
3221 OriginalTy->getVectorNumElements());
3222 if (TruncatedTy == OriginalTy)
3223 continue;
3224
3225 IRBuilder<> B(cast<Instruction>(I));
3226 auto ShrinkOperand = [&](Value *V) -> Value * {
3227 if (auto *ZI = dyn_cast<ZExtInst>(V))
3228 if (ZI->getSrcTy() == TruncatedTy)
3229 return ZI->getOperand(0);
3230 return B.CreateZExtOrTrunc(V, TruncatedTy);
3231 };
3232
3233 // The actual instruction modification depends on the instruction type,
3234 // unfortunately.
3235 Value *NewI = nullptr;
3236 if (auto *BO = dyn_cast<BinaryOperator>(I)) {
3237 NewI = B.CreateBinOp(BO->getOpcode(), ShrinkOperand(BO->getOperand(0)),
3238 ShrinkOperand(BO->getOperand(1)));
3239
3240 // Any wrapping introduced by shrinking this operation shouldn't be
3241 // considered undefined behavior. So, we can't unconditionally copy
3242 // arithmetic wrapping flags to NewI.
3243 cast<BinaryOperator>(NewI)->copyIRFlags(I, /*IncludeWrapFlags=*/false);
3244 } else if (auto *CI = dyn_cast<ICmpInst>(I)) {
3245 NewI =
3246 B.CreateICmp(CI->getPredicate(), ShrinkOperand(CI->getOperand(0)),
3247 ShrinkOperand(CI->getOperand(1)));
3248 } else if (auto *SI = dyn_cast<SelectInst>(I)) {
3249 NewI = B.CreateSelect(SI->getCondition(),
3250 ShrinkOperand(SI->getTrueValue()),
3251 ShrinkOperand(SI->getFalseValue()));
3252 } else if (auto *CI = dyn_cast<CastInst>(I)) {
3253 switch (CI->getOpcode()) {
3254 default:
3255 llvm_unreachable("Unhandled cast!")::llvm::llvm_unreachable_internal("Unhandled cast!", "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3255)
;
3256 case Instruction::Trunc:
3257 NewI = ShrinkOperand(CI->getOperand(0));
3258 break;
3259 case Instruction::SExt:
3260 NewI = B.CreateSExtOrTrunc(
3261 CI->getOperand(0),
3262 smallestIntegerVectorType(OriginalTy, TruncatedTy));
3263 break;
3264 case Instruction::ZExt:
3265 NewI = B.CreateZExtOrTrunc(
3266 CI->getOperand(0),
3267 smallestIntegerVectorType(OriginalTy, TruncatedTy));
3268 break;
3269 }
3270 } else if (auto *SI = dyn_cast<ShuffleVectorInst>(I)) {
3271 auto Elements0 = SI->getOperand(0)->getType()->getVectorNumElements();
3272 auto *O0 = B.CreateZExtOrTrunc(
3273 SI->getOperand(0), VectorType::get(ScalarTruncatedTy, Elements0));
3274 auto Elements1 = SI->getOperand(1)->getType()->getVectorNumElements();
3275 auto *O1 = B.CreateZExtOrTrunc(
3276 SI->getOperand(1), VectorType::get(ScalarTruncatedTy, Elements1));
3277
3278 NewI = B.CreateShuffleVector(O0, O1, SI->getMask());
3279 } else if (isa<LoadInst>(I) || isa<PHINode>(I)) {
3280 // Don't do anything with the operands, just extend the result.
3281 continue;
3282 } else if (auto *IE = dyn_cast<InsertElementInst>(I)) {
3283 auto Elements = IE->getOperand(0)->getType()->getVectorNumElements();
3284 auto *O0 = B.CreateZExtOrTrunc(
3285 IE->getOperand(0), VectorType::get(ScalarTruncatedTy, Elements));
3286 auto *O1 = B.CreateZExtOrTrunc(IE->getOperand(1), ScalarTruncatedTy);
3287 NewI = B.CreateInsertElement(O0, O1, IE->getOperand(2));
3288 } else if (auto *EE = dyn_cast<ExtractElementInst>(I)) {
3289 auto Elements = EE->getOperand(0)->getType()->getVectorNumElements();
3290 auto *O0 = B.CreateZExtOrTrunc(
3291 EE->getOperand(0), VectorType::get(ScalarTruncatedTy, Elements));
3292 NewI = B.CreateExtractElement(O0, EE->getOperand(2));
3293 } else {
3294 // If we don't know what to do, be conservative and don't do anything.
3295 continue;
3296 }
3297
3298 // Lastly, extend the result.
3299 NewI->takeName(cast<Instruction>(I));
3300 Value *Res = B.CreateZExtOrTrunc(NewI, OriginalTy);
3301 I->replaceAllUsesWith(Res);
3302 cast<Instruction>(I)->eraseFromParent();
3303 Erased.insert(I);
3304 VectorLoopValueMap.resetVectorValue(KV.first, Part, Res);
3305 }
3306 }
3307
3308 // We'll have created a bunch of ZExts that are now parentless. Clean up.
3309 for (const auto &KV : Cost->getMinimalBitwidths()) {
3310 // If the value wasn't vectorized, we must maintain the original scalar
3311 // type. The absence of the value from VectorLoopValueMap indicates that it
3312 // wasn't vectorized.
3313 if (!VectorLoopValueMap.hasAnyVectorValue(KV.first))
3314 continue;
3315 for (unsigned Part = 0; Part < UF; ++Part) {
3316 Value *I = getOrCreateVectorValue(KV.first, Part);
3317 ZExtInst *Inst = dyn_cast<ZExtInst>(I);
3318 if (Inst && Inst->use_empty()) {
3319 Value *NewI = Inst->getOperand(0);
3320 Inst->eraseFromParent();
3321 VectorLoopValueMap.resetVectorValue(KV.first, Part, NewI);
3322 }
3323 }
3324 }
3325}
3326
3327void InnerLoopVectorizer::fixVectorizedLoop() {
3328 // Insert truncates and extends for any truncated instructions as hints to
3329 // InstCombine.
3330 if (VF > 1)
3331 truncateToMinimalBitwidths();
3332
3333 // At this point every instruction in the original loop is widened to a
3334 // vector form. Now we need to fix the recurrences in the loop. These PHI
3335 // nodes are currently empty because we did not want to introduce cycles.
3336 // This is the second stage of vectorizing recurrences.
3337 fixCrossIterationPHIs();
3338
3339 // Update the dominator tree.
3340 //
3341 // FIXME: After creating the structure of the new loop, the dominator tree is
3342 // no longer up-to-date, and it remains that way until we update it
3343 // here. An out-of-date dominator tree is problematic for SCEV,
3344 // because SCEVExpander uses it to guide code generation. The
3345 // vectorizer use SCEVExpanders in several places. Instead, we should
3346 // keep the dominator tree up-to-date as we go.
3347 updateAnalysis();
3348
3349 // Fix-up external users of the induction variables.
3350 for (auto &Entry : *Legal->getInductionVars())
3351 fixupIVUsers(Entry.first, Entry.second,
3352 getOrCreateVectorTripCount(LI->getLoopFor(LoopVectorBody)),
3353 IVEndValues[Entry.first], LoopMiddleBlock);
3354
3355 fixLCSSAPHIs();
3356 for (Instruction *PI : PredicatedInstructions)
3357 sinkScalarOperands(&*PI);
3358
3359 // Remove redundant induction instructions.
3360 cse(LoopVectorBody);
3361}
3362
3363void InnerLoopVectorizer::fixCrossIterationPHIs() {
3364 // In order to support recurrences we need to be able to vectorize Phi nodes.
3365 // Phi nodes have cycles, so we need to vectorize them in two stages. This is
3366 // stage #2: We now need to fix the recurrences by adding incoming edges to
3367 // the currently empty PHI nodes. At this point every instruction in the
3368 // original loop is widened to a vector form so we can use them to construct
3369 // the incoming edges.
3370 for (PHINode &Phi : OrigLoop->getHeader()->phis()) {
3371 // Handle first-order recurrences and reductions that need to be fixed.
3372 if (Legal->isFirstOrderRecurrence(&Phi))
3373 fixFirstOrderRecurrence(&Phi);
3374 else if (Legal->isReductionVariable(&Phi))
3375 fixReduction(&Phi);
3376 }
3377}
3378
3379void InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi) {
3380 // This is the second phase of vectorizing first-order recurrences. An
3381 // overview of the transformation is described below. Suppose we have the
3382 // following loop.
3383 //
3384 // for (int i = 0; i < n; ++i)
3385 // b[i] = a[i] - a[i - 1];
3386 //
3387 // There is a first-order recurrence on "a". For this loop, the shorthand
3388 // scalar IR looks like:
3389 //
3390 // scalar.ph:
3391 // s_init = a[-1]
3392 // br scalar.body
3393 //
3394 // scalar.body:
3395 // i = phi [0, scalar.ph], [i+1, scalar.body]
3396 // s1 = phi [s_init, scalar.ph], [s2, scalar.body]
3397 // s2 = a[i]
3398 // b[i] = s2 - s1
3399 // br cond, scalar.body, ...
3400 //
3401 // In this example, s1 is a recurrence because it's value depends on the
3402 // previous iteration. In the first phase of vectorization, we created a
3403 // temporary value for s1. We now complete the vectorization and produce the
3404 // shorthand vector IR shown below (for VF = 4, UF = 1).
3405 //
3406 // vector.ph:
3407 // v_init = vector(..., ..., ..., a[-1])
3408 // br vector.body
3409 //
3410 // vector.body
3411 // i = phi [0, vector.ph], [i+4, vector.body]
3412 // v1 = phi [v_init, vector.ph], [v2, vector.body]
3413 // v2 = a[i, i+1, i+2, i+3];
3414 // v3 = vector(v1(3), v2(0, 1, 2))
3415 // b[i, i+1, i+2, i+3] = v2 - v3
3416 // br cond, vector.body, middle.block
3417 //
3418 // middle.block:
3419 // x = v2(3)
3420 // br scalar.ph
3421 //
3422 // scalar.ph:
3423 // s_init = phi [x, middle.block], [a[-1], otherwise]
3424 // br scalar.body
3425 //
3426 // After execution completes the vector loop, we extract the next value of
3427 // the recurrence (x) to use as the initial value in the scalar loop.
3428
3429 // Get the original loop preheader and single loop latch.
3430 auto *Preheader = OrigLoop->getLoopPreheader();
3431 auto *Latch = OrigLoop->getLoopLatch();
3432
3433 // Get the initial and previous values of the scalar recurrence.
3434 auto *ScalarInit = Phi->getIncomingValueForBlock(Preheader);
3435 auto *Previous = Phi->getIncomingValueForBlock(Latch);
3436
3437 // Create a vector from the initial value.
3438 auto *VectorInit = ScalarInit;
3439 if (VF > 1) {
3440 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
3441 VectorInit = Builder.CreateInsertElement(
3442 UndefValue::get(VectorType::get(VectorInit->getType(), VF)), VectorInit,
3443 Builder.getInt32(VF - 1), "vector.recur.init");
3444 }
3445
3446 // We constructed a temporary phi node in the first phase of vectorization.
3447 // This phi node will eventually be deleted.
3448 Builder.SetInsertPoint(
3449 cast<Instruction>(VectorLoopValueMap.getVectorValue(Phi, 0)));
3450
3451 // Create a phi node for the new recurrence. The current value will either be
3452 // the initial value inserted into a vector or loop-varying vector value.
3453 auto *VecPhi = Builder.CreatePHI(VectorInit->getType(), 2, "vector.recur");
3454 VecPhi->addIncoming(VectorInit, LoopVectorPreHeader);
3455
3456 // Get the vectorized previous value of the last part UF - 1. It appears last
3457 // among all unrolled iterations, due to the order of their construction.
3458 Value *PreviousLastPart = getOrCreateVectorValue(Previous, UF - 1);
3459
3460 // Set the insertion point after the previous value if it is an instruction.
3461 // Note that the previous value may have been constant-folded so it is not
3462 // guaranteed to be an instruction in the vector loop. Also, if the previous
3463 // value is a phi node, we should insert after all the phi nodes to avoid
3464 // breaking basic block verification.
3465 if (LI->getLoopFor(LoopVectorBody)->isLoopInvariant(PreviousLastPart) ||
3466 isa<PHINode>(PreviousLastPart))
3467 Builder.SetInsertPoint(&*LoopVectorBody->getFirstInsertionPt());
3468 else
3469 Builder.SetInsertPoint(
3470 &*++BasicBlock::iterator(cast<Instruction>(PreviousLastPart)));
3471
3472 // We will construct a vector for the recurrence by combining the values for
3473 // the current and previous iterations. This is the required shuffle mask.
3474 SmallVector<Constant *, 8> ShuffleMask(VF);
3475 ShuffleMask[0] = Builder.getInt32(VF - 1);
3476 for (unsigned I = 1; I < VF; ++I)
3477 ShuffleMask[I] = Builder.getInt32(I + VF - 1);
3478
3479 // The vector from which to take the initial value for the current iteration
3480 // (actual or unrolled). Initially, this is the vector phi node.
3481 Value *Incoming = VecPhi;
3482
3483 // Shuffle the current and previous vector and update the vector parts.
3484 for (unsigned Part = 0; Part < UF; ++Part) {
3485 Value *PreviousPart = getOrCreateVectorValue(Previous, Part);
3486 Value *PhiPart = VectorLoopValueMap.getVectorValue(Phi, Part);
3487 auto *Shuffle =
3488 VF > 1 ? Builder.CreateShuffleVector(Incoming, PreviousPart,
3489 ConstantVector::get(ShuffleMask))
3490 : Incoming;
3491 PhiPart->replaceAllUsesWith(Shuffle);
3492 cast<Instruction>(PhiPart)->eraseFromParent();
3493 VectorLoopValueMap.resetVectorValue(Phi, Part, Shuffle);
3494 Incoming = PreviousPart;
3495 }
3496
3497 // Fix the latch value of the new recurrence in the vector loop.
3498 VecPhi->addIncoming(Incoming, LI->getLoopFor(LoopVectorBody)->getLoopLatch());
3499
3500 // Extract the last vector element in the middle block. This will be the
3501 // initial value for the recurrence when jumping to the scalar loop.
3502 auto *ExtractForScalar = Incoming;
3503 if (VF > 1) {
3504 Builder.SetInsertPoint(LoopMiddleBlock->getTerminator());
3505 ExtractForScalar = Builder.CreateExtractElement(
3506 ExtractForScalar, Builder.getInt32(VF - 1), "vector.recur.extract");
3507 }
3508 // Extract the second last element in the middle block if the
3509 // Phi is used outside the loop. We need to extract the phi itself
3510 // and not the last element (the phi update in the current iteration). This
3511 // will be the value when jumping to the exit block from the LoopMiddleBlock,
3512 // when the scalar loop is not run at all.
3513 Value *ExtractForPhiUsedOutsideLoop = nullptr;
3514 if (VF > 1)
3515 ExtractForPhiUsedOutsideLoop = Builder.CreateExtractElement(
3516 Incoming, Builder.getInt32(VF - 2), "vector.recur.extract.for.phi");
3517 // When loop is unrolled without vectorizing, initialize
3518 // ExtractForPhiUsedOutsideLoop with the value just prior to unrolled value of
3519 // `Incoming`. This is analogous to the vectorized case above: extracting the
3520 // second last element when VF > 1.
3521 else if (UF > 1)
3522 ExtractForPhiUsedOutsideLoop = getOrCreateVectorValue(Previous, UF - 2);
3523
3524 // Fix the initial value of the original recurrence in the scalar loop.
3525 Builder.SetInsertPoint(&*LoopScalarPreHeader->begin());
3526 auto *Start = Builder.CreatePHI(Phi->getType(), 2, "scalar.recur.init");
3527 for (auto *BB : predecessors(LoopScalarPreHeader)) {
3528 auto *Incoming = BB == LoopMiddleBlock ? ExtractForScalar : ScalarInit;
3529 Start->addIncoming(Incoming, BB);
3530 }
3531
3532 Phi->setIncomingValue(Phi->getBasicBlockIndex(LoopScalarPreHeader), Start);
3533 Phi->setName("scalar.recur");
3534
3535 // Finally, fix users of the recurrence outside the loop. The users will need
3536 // either the last value of the scalar recurrence or the last value of the
3537 // vector recurrence we extracted in the middle block. Since the loop is in
3538 // LCSSA form, we just need to find all the phi nodes for the original scalar
3539 // recurrence in the exit block, and then add an edge for the middle block.
3540 for (PHINode &LCSSAPhi : LoopExitBlock->phis()) {
3541 if (LCSSAPhi.getIncomingValue(0) == Phi) {
3542 LCSSAPhi.addIncoming(ExtractForPhiUsedOutsideLoop, LoopMiddleBlock);
3543 }
3544 }
3545}
3546
3547void InnerLoopVectorizer::fixReduction(PHINode *Phi) {
3548 Constant *Zero = Builder.getInt32(0);
3549
3550 // Get it's reduction variable descriptor.
3551 assert(Legal->isReductionVariable(Phi) &&(static_cast <bool> (Legal->isReductionVariable(Phi)
&& "Unable to find the reduction variable") ? void (
0) : __assert_fail ("Legal->isReductionVariable(Phi) && \"Unable to find the reduction variable\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3552, __extension__ __PRETTY_FUNCTION__))
3552 "Unable to find the reduction variable")(static_cast <bool> (Legal->isReductionVariable(Phi)
&& "Unable to find the reduction variable") ? void (
0) : __assert_fail ("Legal->isReductionVariable(Phi) && \"Unable to find the reduction variable\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3552, __extension__ __PRETTY_FUNCTION__))
;
3553 RecurrenceDescriptor RdxDesc = (*Legal->getReductionVars())[Phi];
3554
3555 RecurrenceDescriptor::RecurrenceKind RK = RdxDesc.getRecurrenceKind();
3556 TrackingVH<Value> ReductionStartValue = RdxDesc.getRecurrenceStartValue();
3557 Instruction *LoopExitInst = RdxDesc.getLoopExitInstr();
3558 RecurrenceDescriptor::MinMaxRecurrenceKind MinMaxKind =
3559 RdxDesc.getMinMaxRecurrenceKind();
3560 setDebugLocFromInst(Builder, ReductionStartValue);
3561
3562 // We need to generate a reduction vector from the incoming scalar.
3563 // To do so, we need to generate the 'identity' vector and override
3564 // one of the elements with the incoming scalar reduction. We need
3565 // to do it in the vector-loop preheader.
3566 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
3567
3568 // This is the vector-clone of the value that leaves the loop.
3569 Type *VecTy = getOrCreateVectorValue(LoopExitInst, 0)->getType();
3570
3571 // Find the reduction identity variable. Zero for addition, or, xor,
3572 // one for multiplication, -1 for And.
3573 Value *Identity;
3574 Value *VectorStart;
3575 if (RK == RecurrenceDescriptor::RK_IntegerMinMax ||
3576 RK == RecurrenceDescriptor::RK_FloatMinMax) {
3577 // MinMax reduction have the start value as their identify.
3578 if (VF == 1) {
3579 VectorStart = Identity = ReductionStartValue;
3580 } else {
3581 VectorStart = Identity =
3582 Builder.CreateVectorSplat(VF, ReductionStartValue, "minmax.ident");
3583 }
3584 } else {
3585 // Handle other reduction kinds:
3586 Constant *Iden = RecurrenceDescriptor::getRecurrenceIdentity(
3587 RK, VecTy->getScalarType());
3588 if (VF == 1) {
3589 Identity = Iden;
3590 // This vector is the Identity vector where the first element is the
3591 // incoming scalar reduction.
3592 VectorStart = ReductionStartValue;
3593 } else {
3594 Identity = ConstantVector::getSplat(VF, Iden);
3595
3596 // This vector is the Identity vector where the first element is the
3597 // incoming scalar reduction.
3598 VectorStart =
3599 Builder.CreateInsertElement(Identity, ReductionStartValue, Zero);
3600 }
3601 }
3602
3603 // Fix the vector-loop phi.
3604
3605 // Reductions do not have to start at zero. They can start with
3606 // any loop invariant values.
3607 BasicBlock *Latch = OrigLoop->getLoopLatch();
3608 Value *LoopVal = Phi->getIncomingValueForBlock(Latch);
3609 for (unsigned Part = 0; Part < UF; ++Part) {
3610 Value *VecRdxPhi = getOrCreateVectorValue(Phi, Part);
3611 Value *Val = getOrCreateVectorValue(LoopVal, Part);
3612 // Make sure to add the reduction stat value only to the
3613 // first unroll part.
3614 Value *StartVal = (Part == 0) ? VectorStart : Identity;
3615 cast<PHINode>(VecRdxPhi)->addIncoming(StartVal, LoopVectorPreHeader);
3616 cast<PHINode>(VecRdxPhi)
3617 ->addIncoming(Val, LI->getLoopFor(LoopVectorBody)->getLoopLatch());
3618 }
3619
3620 // Before each round, move the insertion point right between
3621 // the PHIs and the values we are going to write.
3622 // This allows us to write both PHINodes and the extractelement
3623 // instructions.
3624 Builder.SetInsertPoint(&*LoopMiddleBlock->getFirstInsertionPt());
3625
3626 setDebugLocFromInst(Builder, LoopExitInst);
3627
3628 // If the vector reduction can be performed in a smaller type, we truncate
3629 // then extend the loop exit value to enable InstCombine to evaluate the
3630 // entire expression in the smaller type.
3631 if (VF > 1 && Phi->getType() != RdxDesc.getRecurrenceType()) {
3632 Type *RdxVecTy = VectorType::get(RdxDesc.getRecurrenceType(), VF);
3633 Builder.SetInsertPoint(
3634 LI->getLoopFor(LoopVectorBody)->getLoopLatch()->getTerminator());
3635 VectorParts RdxParts(UF);
3636 for (unsigned Part = 0; Part < UF; ++Part) {
3637 RdxParts[Part] = VectorLoopValueMap.getVectorValue(LoopExitInst, Part);
3638 Value *Trunc = Builder.CreateTrunc(RdxParts[Part], RdxVecTy);
3639 Value *Extnd = RdxDesc.isSigned() ? Builder.CreateSExt(Trunc, VecTy)
3640 : Builder.CreateZExt(Trunc, VecTy);
3641 for (Value::user_iterator UI = RdxParts[Part]->user_begin();
3642 UI != RdxParts[Part]->user_end();)
3643 if (*UI != Trunc) {
3644 (*UI++)->replaceUsesOfWith(RdxParts[Part], Extnd);
3645 RdxParts[Part] = Extnd;
3646 } else {
3647 ++UI;
3648 }
3649 }
3650 Builder.SetInsertPoint(&*LoopMiddleBlock->getFirstInsertionPt());
3651 for (unsigned Part = 0; Part < UF; ++Part) {
3652 RdxParts[Part] = Builder.CreateTrunc(RdxParts[Part], RdxVecTy);
3653 VectorLoopValueMap.resetVectorValue(LoopExitInst, Part, RdxParts[Part]);
3654 }
3655 }
3656
3657 // Reduce all of the unrolled parts into a single vector.
3658 Value *ReducedPartRdx = VectorLoopValueMap.getVectorValue(LoopExitInst, 0);
3659 unsigned Op = RecurrenceDescriptor::getRecurrenceBinOp(RK);
3660 setDebugLocFromInst(Builder, ReducedPartRdx);
3661 for (unsigned Part = 1; Part < UF; ++Part) {
3662 Value *RdxPart = VectorLoopValueMap.getVectorValue(LoopExitInst, Part);
3663 if (Op != Instruction::ICmp && Op != Instruction::FCmp)
3664 // Floating point operations had to be 'fast' to enable the reduction.
3665 ReducedPartRdx = addFastMathFlag(
3666 Builder.CreateBinOp((Instruction::BinaryOps)Op, RdxPart,
3667 ReducedPartRdx, "bin.rdx"));
3668 else
3669 ReducedPartRdx = RecurrenceDescriptor::createMinMaxOp(
3670 Builder, MinMaxKind, ReducedPartRdx, RdxPart);
3671 }
3672
3673 if (VF > 1) {
3674 bool NoNaN = Legal->hasFunNoNaNAttr();
3675 ReducedPartRdx =
3676 createTargetReduction(Builder, TTI, RdxDesc, ReducedPartRdx, NoNaN);
3677 // If the reduction can be performed in a smaller type, we need to extend
3678 // the reduction to the wider type before we branch to the original loop.
3679 if (Phi->getType() != RdxDesc.getRecurrenceType())
3680 ReducedPartRdx =
3681 RdxDesc.isSigned()
3682 ? Builder.CreateSExt(ReducedPartRdx, Phi->getType())
3683 : Builder.CreateZExt(ReducedPartRdx, Phi->getType());
3684 }
3685
3686 // Create a phi node that merges control-flow from the backedge-taken check
3687 // block and the middle block.
3688 PHINode *BCBlockPhi = PHINode::Create(Phi->getType(), 2, "bc.merge.rdx",
3689 LoopScalarPreHeader->getTerminator());
3690 for (unsigned I = 0, E = LoopBypassBlocks.size(); I != E; ++I)
3691 BCBlockPhi->addIncoming(ReductionStartValue, LoopBypassBlocks[I]);
3692 BCBlockPhi->addIncoming(ReducedPartRdx, LoopMiddleBlock);
3693
3694 // Now, we need to fix the users of the reduction variable
3695 // inside and outside of the scalar remainder loop.
3696 // We know that the loop is in LCSSA form. We need to update the
3697 // PHI nodes in the exit blocks.
3698 for (PHINode &LCSSAPhi : LoopExitBlock->phis()) {
3699 // All PHINodes need to have a single entry edge, or two if
3700 // we already fixed them.
3701 assert(LCSSAPhi.getNumIncomingValues() < 3 && "Invalid LCSSA PHI")(static_cast <bool> (LCSSAPhi.getNumIncomingValues() <
3 && "Invalid LCSSA PHI") ? void (0) : __assert_fail
("LCSSAPhi.getNumIncomingValues() < 3 && \"Invalid LCSSA PHI\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3701, __extension__ __PRETTY_FUNCTION__))
;
3702
3703 // We found a reduction value exit-PHI. Update it with the
3704 // incoming bypass edge.
3705 if (LCSSAPhi.getIncomingValue(0) == LoopExitInst)
3706 LCSSAPhi.addIncoming(ReducedPartRdx, LoopMiddleBlock);
3707 } // end of the LCSSA phi scan.
3708
3709 // Fix the scalar loop reduction variable with the incoming reduction sum
3710 // from the vector body and from the backedge value.
3711 int IncomingEdgeBlockIdx =
3712 Phi->getBasicBlockIndex(OrigLoop->getLoopLatch());
3713 assert(IncomingEdgeBlockIdx >= 0 && "Invalid block index")(static_cast <bool> (IncomingEdgeBlockIdx >= 0 &&
"Invalid block index") ? void (0) : __assert_fail ("IncomingEdgeBlockIdx >= 0 && \"Invalid block index\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3713, __extension__ __PRETTY_FUNCTION__))
;
3714 // Pick the other block.
3715 int SelfEdgeBlockIdx = (IncomingEdgeBlockIdx ? 0 : 1);
3716 Phi->setIncomingValue(SelfEdgeBlockIdx, BCBlockPhi);
3717 Phi->setIncomingValue(IncomingEdgeBlockIdx, LoopExitInst);
3718}
3719
3720void InnerLoopVectorizer::fixLCSSAPHIs() {
3721 for (PHINode &LCSSAPhi : LoopExitBlock->phis()) {
3722 if (LCSSAPhi.getNumIncomingValues() == 1) {
3723 assert(OrigLoop->isLoopInvariant(LCSSAPhi.getIncomingValue(0)) &&(static_cast <bool> (OrigLoop->isLoopInvariant(LCSSAPhi
.getIncomingValue(0)) && "Incoming value isn't loop invariant"
) ? void (0) : __assert_fail ("OrigLoop->isLoopInvariant(LCSSAPhi.getIncomingValue(0)) && \"Incoming value isn't loop invariant\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3724, __extension__ __PRETTY_FUNCTION__))
3724 "Incoming value isn't loop invariant")(static_cast <bool> (OrigLoop->isLoopInvariant(LCSSAPhi
.getIncomingValue(0)) && "Incoming value isn't loop invariant"
) ? void (0) : __assert_fail ("OrigLoop->isLoopInvariant(LCSSAPhi.getIncomingValue(0)) && \"Incoming value isn't loop invariant\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3724, __extension__ __PRETTY_FUNCTION__))
;
3725 LCSSAPhi.addIncoming(LCSSAPhi.getIncomingValue(0), LoopMiddleBlock);
3726 }
3727 }
3728}
3729
3730void InnerLoopVectorizer::sinkScalarOperands(Instruction *PredInst) {
3731 // The basic block and loop containing the predicated instruction.
3732 auto *PredBB = PredInst->getParent();
3733 auto *VectorLoop = LI->getLoopFor(PredBB);
3734
3735 // Initialize a worklist with the operands of the predicated instruction.
3736 SetVector<Value *> Worklist(PredInst->op_begin(), PredInst->op_end());
3737
3738 // Holds instructions that we need to analyze again. An instruction may be
3739 // reanalyzed if we don't yet know if we can sink it or not.
3740 SmallVector<Instruction *, 8> InstsToReanalyze;
3741
3742 // Returns true if a given use occurs in the predicated block. Phi nodes use
3743 // their operands in their corresponding predecessor blocks.
3744 auto isBlockOfUsePredicated = [&](Use &U) -> bool {
3745 auto *I = cast<Instruction>(U.getUser());
3746 BasicBlock *BB = I->getParent();
3747 if (auto *Phi = dyn_cast<PHINode>(I))
3748 BB = Phi->getIncomingBlock(
3749 PHINode::getIncomingValueNumForOperand(U.getOperandNo()));
3750 return BB == PredBB;
3751 };
3752
3753 // Iteratively sink the scalarized operands of the predicated instruction
3754 // into the block we created for it. When an instruction is sunk, it's
3755 // operands are then added to the worklist. The algorithm ends after one pass
3756 // through the worklist doesn't sink a single instruction.
3757 bool Changed;
3758 do {
3759 // Add the instructions that need to be reanalyzed to the worklist, and
3760 // reset the changed indicator.
3761 Worklist.insert(InstsToReanalyze.begin(), InstsToReanalyze.end());
3762 InstsToReanalyze.clear();
3763 Changed = false;
3764
3765 while (!Worklist.empty()) {
3766 auto *I = dyn_cast<Instruction>(Worklist.pop_back_val());
3767
3768 // We can't sink an instruction if it is a phi node, is already in the
3769 // predicated block, is not in the loop, or may have side effects.
3770 if (!I || isa<PHINode>(I) || I->getParent() == PredBB ||
3771 !VectorLoop->contains(I) || I->mayHaveSideEffects())
3772 continue;
3773
3774 // It's legal to sink the instruction if all its uses occur in the
3775 // predicated block. Otherwise, there's nothing to do yet, and we may
3776 // need to reanalyze the instruction.
3777 if (!llvm::all_of(I->uses(), isBlockOfUsePredicated)) {
3778 InstsToReanalyze.push_back(I);
3779 continue;
3780 }
3781
3782 // Move the instruction to the beginning of the predicated block, and add
3783 // it's operands to the worklist.
3784 I->moveBefore(&*PredBB->getFirstInsertionPt());
3785 Worklist.insert(I->op_begin(), I->op_end());
3786
3787 // The sinking may have enabled other instructions to be sunk, so we will
3788 // need to iterate.
3789 Changed = true;
3790 }
3791 } while (Changed);
3792}
3793
3794void InnerLoopVectorizer::widenPHIInstruction(Instruction *PN, unsigned UF,
3795 unsigned VF) {
3796 assert(PN->getParent() == OrigLoop->getHeader() &&(static_cast <bool> (PN->getParent() == OrigLoop->
getHeader() && "Non-header phis should have been handled elsewhere"
) ? void (0) : __assert_fail ("PN->getParent() == OrigLoop->getHeader() && \"Non-header phis should have been handled elsewhere\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3797, __extension__ __PRETTY_FUNCTION__))
3797 "Non-header phis should have been handled elsewhere")(static_cast <bool> (PN->getParent() == OrigLoop->
getHeader() && "Non-header phis should have been handled elsewhere"
) ? void (0) : __assert_fail ("PN->getParent() == OrigLoop->getHeader() && \"Non-header phis should have been handled elsewhere\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3797, __extension__ __PRETTY_FUNCTION__))
;
3798
3799 PHINode *P = cast<PHINode>(PN);
3800 // In order to support recurrences we need to be able to vectorize Phi nodes.
3801 // Phi nodes have cycles, so we need to vectorize them in two stages. This is
3802 // stage #1: We create a new vector PHI node with no incoming edges. We'll use
3803 // this value when we vectorize all of the instructions that use the PHI.
3804 if (Legal->isReductionVariable(P) || Legal->isFirstOrderRecurrence(P)) {
3805 for (unsigned Part = 0; Part < UF; ++Part) {
3806 // This is phase one of vectorizing PHIs.
3807 Type *VecTy =
3808 (VF == 1) ? PN->getType() : VectorType::get(PN->getType(), VF);
3809 Value *EntryPart = PHINode::Create(
3810 VecTy, 2, "vec.phi", &*LoopVectorBody->getFirstInsertionPt());
3811 VectorLoopValueMap.setVectorValue(P, Part, EntryPart);
3812 }
3813 return;
3814 }
3815
3816 setDebugLocFromInst(Builder, P);
3817
3818 // This PHINode must be an induction variable.
3819 // Make sure that we know about it.
3820 assert(Legal->getInductionVars()->count(P) && "Not an induction variable")(static_cast <bool> (Legal->getInductionVars()->count
(P) && "Not an induction variable") ? void (0) : __assert_fail
("Legal->getInductionVars()->count(P) && \"Not an induction variable\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3820, __extension__ __PRETTY_FUNCTION__))
;
3821
3822 InductionDescriptor II = Legal->getInductionVars()->lookup(P);
3823 const DataLayout &DL = OrigLoop->getHeader()->getModule()->getDataLayout();
3824
3825 // FIXME: The newly created binary instructions should contain nsw/nuw flags,
3826 // which can be found from the original scalar operations.
3827 switch (II.getKind()) {
3828 case InductionDescriptor::IK_NoInduction:
3829 llvm_unreachable("Unknown induction")::llvm::llvm_unreachable_internal("Unknown induction", "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3829)
;
3830 case InductionDescriptor::IK_IntInduction:
3831 case InductionDescriptor::IK_FpInduction:
3832 llvm_unreachable("Integer/fp induction is handled elsewhere.")::llvm::llvm_unreachable_internal("Integer/fp induction is handled elsewhere."
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3832)
;
3833 case InductionDescriptor::IK_PtrInduction: {
3834 // Handle the pointer induction variable case.
3835 assert(P->getType()->isPointerTy() && "Unexpected type.")(static_cast <bool> (P->getType()->isPointerTy() &&
"Unexpected type.") ? void (0) : __assert_fail ("P->getType()->isPointerTy() && \"Unexpected type.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3835, __extension__ __PRETTY_FUNCTION__))
;
3836 // This is the normalized GEP that starts counting at zero.
3837 Value *PtrInd = Induction;
3838 PtrInd = Builder.CreateSExtOrTrunc(PtrInd, II.getStep()->getType());
3839 // Determine the number of scalars we need to generate for each unroll
3840 // iteration. If the instruction is uniform, we only need to generate the
3841 // first lane. Otherwise, we generate all VF values.
3842 unsigned Lanes = Cost->isUniformAfterVectorization(P, VF) ? 1 : VF;
3843 // These are the scalar results. Notice that we don't generate vector GEPs
3844 // because scalar GEPs result in better code.
3845 for (unsigned Part = 0; Part < UF; ++Part) {
3846 for (unsigned Lane = 0; Lane < Lanes; ++Lane) {
3847 Constant *Idx = ConstantInt::get(PtrInd->getType(), Lane + Part * VF);
3848 Value *GlobalIdx = Builder.CreateAdd(PtrInd, Idx);
3849 Value *SclrGep = II.transform(Builder, GlobalIdx, PSE.getSE(), DL);
3850 SclrGep->setName("next.gep");
3851 VectorLoopValueMap.setScalarValue(P, {Part, Lane}, SclrGep);
3852 }
3853 }
3854 return;
3855 }
3856 }
3857}
3858
3859/// A helper function for checking whether an integer division-related
3860/// instruction may divide by zero (in which case it must be predicated if
3861/// executed conditionally in the scalar code).
3862/// TODO: It may be worthwhile to generalize and check isKnownNonZero().
3863/// Non-zero divisors that are non compile-time constants will not be
3864/// converted into multiplication, so we will still end up scalarizing
3865/// the division, but can do so w/o predication.
3866static bool mayDivideByZero(Instruction &I) {
3867 assert((I.getOpcode() == Instruction::UDiv ||(static_cast <bool> ((I.getOpcode() == Instruction::UDiv
|| I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction
::URem || I.getOpcode() == Instruction::SRem) && "Unexpected instruction"
) ? void (0) : __assert_fail ("(I.getOpcode() == Instruction::UDiv || I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction::URem || I.getOpcode() == Instruction::SRem) && \"Unexpected instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3871, __extension__ __PRETTY_FUNCTION__))
3868 I.getOpcode() == Instruction::SDiv ||(static_cast <bool> ((I.getOpcode() == Instruction::UDiv
|| I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction
::URem || I.getOpcode() == Instruction::SRem) && "Unexpected instruction"
) ? void (0) : __assert_fail ("(I.getOpcode() == Instruction::UDiv || I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction::URem || I.getOpcode() == Instruction::SRem) && \"Unexpected instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3871, __extension__ __PRETTY_FUNCTION__))
3869 I.getOpcode() == Instruction::URem ||(static_cast <bool> ((I.getOpcode() == Instruction::UDiv
|| I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction
::URem || I.getOpcode() == Instruction::SRem) && "Unexpected instruction"
) ? void (0) : __assert_fail ("(I.getOpcode() == Instruction::UDiv || I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction::URem || I.getOpcode() == Instruction::SRem) && \"Unexpected instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3871, __extension__ __PRETTY_FUNCTION__))
3870 I.getOpcode() == Instruction::SRem) &&(static_cast <bool> ((I.getOpcode() == Instruction::UDiv
|| I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction
::URem || I.getOpcode() == Instruction::SRem) && "Unexpected instruction"
) ? void (0) : __assert_fail ("(I.getOpcode() == Instruction::UDiv || I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction::URem || I.getOpcode() == Instruction::SRem) && \"Unexpected instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3871, __extension__ __PRETTY_FUNCTION__))
3871 "Unexpected instruction")(static_cast <bool> ((I.getOpcode() == Instruction::UDiv
|| I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction
::URem || I.getOpcode() == Instruction::SRem) && "Unexpected instruction"
) ? void (0) : __assert_fail ("(I.getOpcode() == Instruction::UDiv || I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction::URem || I.getOpcode() == Instruction::SRem) && \"Unexpected instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3871, __extension__ __PRETTY_FUNCTION__))
;
3872 Value *Divisor = I.getOperand(1);
3873 auto *CInt = dyn_cast<ConstantInt>(Divisor);
3874 return !CInt || CInt->isZero();
3875}
3876
3877void InnerLoopVectorizer::widenInstruction(Instruction &I) {
3878 switch (I.getOpcode()) {
3879 case Instruction::Br:
3880 case Instruction::PHI:
3881 llvm_unreachable("This instruction is handled by a different recipe.")::llvm::llvm_unreachable_internal("This instruction is handled by a different recipe."
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3881)
;
3882 case Instruction::GetElementPtr: {
3883 // Construct a vector GEP by widening the operands of the scalar GEP as
3884 // necessary. We mark the vector GEP 'inbounds' if appropriate. A GEP
3885 // results in a vector of pointers when at least one operand of the GEP
3886 // is vector-typed. Thus, to keep the representation compact, we only use
3887 // vector-typed operands for loop-varying values.
3888 auto *GEP = cast<GetElementPtrInst>(&I);
3889
3890 if (VF > 1 && OrigLoop->hasLoopInvariantOperands(GEP)) {
3891 // If we are vectorizing, but the GEP has only loop-invariant operands,
3892 // the GEP we build (by only using vector-typed operands for
3893 // loop-varying values) would be a scalar pointer. Thus, to ensure we
3894 // produce a vector of pointers, we need to either arbitrarily pick an
3895 // operand to broadcast, or broadcast a clone of the original GEP.
3896 // Here, we broadcast a clone of the original.
3897 //
3898 // TODO: If at some point we decide to scalarize instructions having
3899 // loop-invariant operands, this special case will no longer be
3900 // required. We would add the scalarization decision to
3901 // collectLoopScalars() and teach getVectorValue() to broadcast
3902 // the lane-zero scalar value.
3903 auto *Clone = Builder.Insert(GEP->clone());
3904 for (unsigned Part = 0; Part < UF; ++Part) {
3905 Value *EntryPart = Builder.CreateVectorSplat(VF, Clone);
3906 VectorLoopValueMap.setVectorValue(&I, Part, EntryPart);
3907 addMetadata(EntryPart, GEP);
3908 }
3909 } else {
3910 // If the GEP has at least one loop-varying operand, we are sure to
3911 // produce a vector of pointers. But if we are only unrolling, we want
3912 // to produce a scalar GEP for each unroll part. Thus, the GEP we
3913 // produce with the code below will be scalar (if VF == 1) or vector
3914 // (otherwise). Note that for the unroll-only case, we still maintain
3915 // values in the vector mapping with initVector, as we do for other
3916 // instructions.
3917 for (unsigned Part = 0; Part < UF; ++Part) {
3918 // The pointer operand of the new GEP. If it's loop-invariant, we
3919 // won't broadcast it.
3920 auto *Ptr =
3921 OrigLoop->isLoopInvariant(GEP->getPointerOperand())
3922 ? GEP->getPointerOperand()
3923 : getOrCreateVectorValue(GEP->getPointerOperand(), Part);
3924
3925 // Collect all the indices for the new GEP. If any index is
3926 // loop-invariant, we won't broadcast it.
3927 SmallVector<Value *, 4> Indices;
3928 for (auto &U : make_range(GEP->idx_begin(), GEP->idx_end())) {
3929 if (OrigLoop->isLoopInvariant(U.get()))
3930 Indices.push_back(U.get());
3931 else
3932 Indices.push_back(getOrCreateVectorValue(U.get(), Part));
3933 }
3934
3935 // Create the new GEP. Note that this GEP may be a scalar if VF == 1,
3936 // but it should be a vector, otherwise.
3937 auto *NewGEP = GEP->isInBounds()
3938 ? Builder.CreateInBoundsGEP(Ptr, Indices)
3939 : Builder.CreateGEP(Ptr, Indices);
3940 assert((VF == 1 || NewGEP->getType()->isVectorTy()) &&(static_cast <bool> ((VF == 1 || NewGEP->getType()->
isVectorTy()) && "NewGEP is not a pointer vector") ? void
(0) : __assert_fail ("(VF == 1 || NewGEP->getType()->isVectorTy()) && \"NewGEP is not a pointer vector\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3941, __extension__ __PRETTY_FUNCTION__))
3941 "NewGEP is not a pointer vector")(static_cast <bool> ((VF == 1 || NewGEP->getType()->
isVectorTy()) && "NewGEP is not a pointer vector") ? void
(0) : __assert_fail ("(VF == 1 || NewGEP->getType()->isVectorTy()) && \"NewGEP is not a pointer vector\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3941, __extension__ __PRETTY_FUNCTION__))
;
3942 VectorLoopValueMap.setVectorValue(&I, Part, NewGEP);
3943 addMetadata(NewGEP, GEP);
3944 }
3945 }
3946
3947 break;
3948 }
3949 case Instruction::UDiv:
3950 case Instruction::SDiv:
3951 case Instruction::SRem:
3952 case Instruction::URem:
3953 case Instruction::Add:
3954 case Instruction::FAdd:
3955 case Instruction::Sub:
3956 case Instruction::FSub:
3957 case Instruction::Mul:
3958 case Instruction::FMul:
3959 case Instruction::FDiv:
3960 case Instruction::FRem:
3961 case Instruction::Shl:
3962 case Instruction::LShr:
3963 case Instruction::AShr:
3964 case Instruction::And:
3965 case Instruction::Or:
3966 case Instruction::Xor: {
3967 // Just widen binops.
3968 auto *BinOp = cast<BinaryOperator>(&I);
3969 setDebugLocFromInst(Builder, BinOp);
3970
3971 for (unsigned Part = 0; Part < UF; ++Part) {
3972 Value *A = getOrCreateVectorValue(BinOp->getOperand(0), Part);
3973 Value *B = getOrCreateVectorValue(BinOp->getOperand(1), Part);
3974 Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A, B);
3975
3976 if (BinaryOperator *VecOp = dyn_cast<BinaryOperator>(V))
3977 VecOp->copyIRFlags(BinOp);
3978
3979 // Use this vector value for all users of the original instruction.
3980 VectorLoopValueMap.setVectorValue(&I, Part, V);
3981 addMetadata(V, BinOp);
3982 }
3983
3984 break;
3985 }
3986 case Instruction::Select: {
3987 // Widen selects.
3988 // If the selector is loop invariant we can create a select
3989 // instruction with a scalar condition. Otherwise, use vector-select.
3990 auto *SE = PSE.getSE();
3991 bool InvariantCond =
3992 SE->isLoopInvariant(PSE.getSCEV(I.getOperand(0)), OrigLoop);
3993 setDebugLocFromInst(Builder, &I);
3994
3995 // The condition can be loop invariant but still defined inside the
3996 // loop. This means that we can't just use the original 'cond' value.
3997 // We have to take the 'vectorized' value and pick the first lane.
3998 // Instcombine will make this a no-op.
3999
4000 auto *ScalarCond = getOrCreateScalarValue(I.getOperand(0), {0, 0});
4001
4002 for (unsigned Part = 0; Part < UF; ++Part) {
4003 Value *Cond = getOrCreateVectorValue(I.getOperand(0), Part);
4004 Value *Op0 = getOrCreateVectorValue(I.getOperand(1), Part);
4005 Value *Op1 = getOrCreateVectorValue(I.getOperand(2), Part);
4006 Value *Sel =
4007 Builder.CreateSelect(InvariantCond ? ScalarCond : Cond, Op0, Op1);
4008 VectorLoopValueMap.setVectorValue(&I, Part, Sel);
4009 addMetadata(Sel, &I);
4010 }
4011
4012 break;
4013 }
4014
4015 case Instruction::ICmp:
4016 case Instruction::FCmp: {
4017 // Widen compares. Generate vector compares.
4018 bool FCmp = (I.getOpcode() == Instruction::FCmp);
4019 auto *Cmp = dyn_cast<CmpInst>(&I);
4020 setDebugLocFromInst(Builder, Cmp);
4021 for (unsigned Part = 0; Part < UF; ++Part) {
4022 Value *A = getOrCreateVectorValue(Cmp->getOperand(0), Part);
4023 Value *B = getOrCreateVectorValue(Cmp->getOperand(1), Part);
4024 Value *C = nullptr;
4025 if (FCmp) {
4026 // Propagate fast math flags.
4027 IRBuilder<>::FastMathFlagGuard FMFG(Builder);
4028 Builder.setFastMathFlags(Cmp->getFastMathFlags());
4029 C = Builder.CreateFCmp(Cmp->getPredicate(), A, B);
4030 } else {
4031 C = Builder.CreateICmp(Cmp->getPredicate(), A, B);
4032 }
4033 VectorLoopValueMap.setVectorValue(&I, Part, C);
4034 addMetadata(C, &I);
4035 }
4036
4037 break;
4038 }
4039
4040 case Instruction::ZExt:
4041 case Instruction::SExt:
4042 case Instruction::FPToUI:
4043 case Instruction::FPToSI:
4044 case Instruction::FPExt:
4045 case Instruction::PtrToInt:
4046 case Instruction::IntToPtr:
4047 case Instruction::SIToFP:
4048 case Instruction::UIToFP:
4049 case Instruction::Trunc:
4050 case Instruction::FPTrunc:
4051 case Instruction::BitCast: {
4052 auto *CI = dyn_cast<CastInst>(&I);
4053 setDebugLocFromInst(Builder, CI);
4054
4055 /// Vectorize casts.
4056 Type *DestTy =
4057 (VF == 1) ? CI->getType() : VectorType::get(CI->getType(), VF);
4058
4059 for (unsigned Part = 0; Part < UF; ++Part) {
4060 Value *A = getOrCreateVectorValue(CI->getOperand(0), Part);
4061 Value *Cast = Builder.CreateCast(CI->getOpcode(), A, DestTy);
4062 VectorLoopValueMap.setVectorValue(&I, Part, Cast);
4063 addMetadata(Cast, &I);
4064 }
4065 break;
4066 }
4067
4068 case Instruction::Call: {
4069 // Ignore dbg intrinsics.
4070 if (isa<DbgInfoIntrinsic>(I))
4071 break;
4072 setDebugLocFromInst(Builder, &I);
4073
4074 Module *M = I.getParent()->getParent()->getParent();
4075 auto *CI = cast<CallInst>(&I);
4076
4077 StringRef FnName = CI->getCalledFunction()->getName();
4078 Function *F = CI->getCalledFunction();
4079 Type *RetTy = ToVectorTy(CI->getType(), VF);
4080 SmallVector<Type *, 4> Tys;
4081 for (Value *ArgOperand : CI->arg_operands())
4082 Tys.push_back(ToVectorTy(ArgOperand->getType(), VF));
4083
4084 Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
4085
4086 // The flag shows whether we use Intrinsic or a usual Call for vectorized
4087 // version of the instruction.
4088 // Is it beneficial to perform intrinsic call compared to lib call?
4089 bool NeedToScalarize;
4090 unsigned CallCost = getVectorCallCost(CI, VF, *TTI, TLI, NeedToScalarize);
4091 bool UseVectorIntrinsic =
4092 ID && getVectorIntrinsicCost(CI, VF, *TTI, TLI) <= CallCost;
4093 assert((UseVectorIntrinsic || !NeedToScalarize) &&(static_cast <bool> ((UseVectorIntrinsic || !NeedToScalarize
) && "Instruction should be scalarized elsewhere.") ?
void (0) : __assert_fail ("(UseVectorIntrinsic || !NeedToScalarize) && \"Instruction should be scalarized elsewhere.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4094, __extension__ __PRETTY_FUNCTION__))
4094 "Instruction should be scalarized elsewhere.")(static_cast <bool> ((UseVectorIntrinsic || !NeedToScalarize
) && "Instruction should be scalarized elsewhere.") ?
void (0) : __assert_fail ("(UseVectorIntrinsic || !NeedToScalarize) && \"Instruction should be scalarized elsewhere.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4094, __extension__ __PRETTY_FUNCTION__))
;
4095
4096 for (unsigned Part = 0; Part < UF; ++Part) {
4097 SmallVector<Value *, 4> Args;
4098 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
4099 Value *Arg = CI->getArgOperand(i);
4100 // Some intrinsics have a scalar argument - don't replace it with a
4101 // vector.
4102 if (!UseVectorIntrinsic || !hasVectorInstrinsicScalarOpd(ID, i))
4103 Arg = getOrCreateVectorValue(CI->getArgOperand(i), Part);
4104 Args.push_back(Arg);
4105 }
4106
4107 Function *VectorF;
4108 if (UseVectorIntrinsic) {
4109 // Use vector version of the intrinsic.
4110 Type *TysForDecl[] = {CI->getType()};
4111 if (VF > 1)
4112 TysForDecl[0] = VectorType::get(CI->getType()->getScalarType(), VF);
4113 VectorF = Intrinsic::getDeclaration(M, ID, TysForDecl);
4114 } else {
4115 // Use vector version of the library call.
4116 StringRef VFnName = TLI->getVectorizedFunction(FnName, VF);
4117 assert(!VFnName.empty() && "Vector function name is empty.")(static_cast <bool> (!VFnName.empty() && "Vector function name is empty."
) ? void (0) : __assert_fail ("!VFnName.empty() && \"Vector function name is empty.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4117, __extension__ __PRETTY_FUNCTION__))
;
4118 VectorF = M->getFunction(VFnName);
4119 if (!VectorF) {
4120 // Generate a declaration
4121 FunctionType *FTy = FunctionType::get(RetTy, Tys, false);
4122 VectorF =
4123 Function::Create(FTy, Function::ExternalLinkage, VFnName, M);
4124 VectorF->copyAttributesFrom(F);
4125 }
4126 }
4127 assert(VectorF && "Can't create vector function.")(static_cast <bool> (VectorF && "Can't create vector function."
) ? void (0) : __assert_fail ("VectorF && \"Can't create vector function.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4127, __extension__ __PRETTY_FUNCTION__))
;
4128
4129 SmallVector<OperandBundleDef, 1> OpBundles;
4130 CI->getOperandBundlesAsDefs(OpBundles);
4131 CallInst *V = Builder.CreateCall(VectorF, Args, OpBundles);
4132
4133 if (isa<FPMathOperator>(V))
4134 V->copyFastMathFlags(CI);
4135
4136 VectorLoopValueMap.setVectorValue(&I, Part, V);
4137 addMetadata(V, &I);
4138 }
4139
4140 break;
4141 }
4142
4143 default:
4144 // This instruction is not vectorized by simple widening.
4145 LLVM_DEBUG(dbgs() << "LV: Found an unhandled instruction: " << I)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an unhandled instruction: "
<< I; } } while (false)
;
4146 llvm_unreachable("Unhandled instruction!")::llvm::llvm_unreachable_internal("Unhandled instruction!", "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4146)
;
4147 } // end of switch.
4148}
4149
4150void InnerLoopVectorizer::updateAnalysis() {
4151 // Forget the original basic block.
4152 PSE.getSE()->forgetLoop(OrigLoop);
4153
4154 // Update the dominator tree information.
4155 assert(DT->properlyDominates(LoopBypassBlocks.front(), LoopExitBlock) &&(static_cast <bool> (DT->properlyDominates(LoopBypassBlocks
.front(), LoopExitBlock) && "Entry does not dominate exit."
) ? void (0) : __assert_fail ("DT->properlyDominates(LoopBypassBlocks.front(), LoopExitBlock) && \"Entry does not dominate exit.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4156, __extension__ __PRETTY_FUNCTION__))
4156 "Entry does not dominate exit.")(static_cast <bool> (DT->properlyDominates(LoopBypassBlocks
.front(), LoopExitBlock) && "Entry does not dominate exit."
) ? void (0) : __assert_fail ("DT->properlyDominates(LoopBypassBlocks.front(), LoopExitBlock) && \"Entry does not dominate exit.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4156, __extension__ __PRETTY_FUNCTION__))
;
4157
4158 DT->addNewBlock(LoopMiddleBlock,
4159 LI->getLoopFor(LoopVectorBody)->getLoopLatch());
4160 DT->addNewBlock(LoopScalarPreHeader, LoopBypassBlocks[0]);
4161 DT->changeImmediateDominator(LoopScalarBody, LoopScalarPreHeader);
4162 DT->changeImmediateDominator(LoopExitBlock, LoopBypassBlocks[0]);
4163 assert(DT->verify(DominatorTree::VerificationLevel::Fast))(static_cast <bool> (DT->verify(DominatorTree::VerificationLevel
::Fast)) ? void (0) : __assert_fail ("DT->verify(DominatorTree::VerificationLevel::Fast)"
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4163, __extension__ __PRETTY_FUNCTION__))
;
4164}
4165
4166void LoopVectorizationCostModel::collectLoopScalars(unsigned VF) {
4167 // We should not collect Scalars more than once per VF. Right now, this
4168 // function is called from collectUniformsAndScalars(), which already does
4169 // this check. Collecting Scalars for VF=1 does not make any sense.
4170 assert(VF >= 2 && !Scalars.count(VF) &&(static_cast <bool> (VF >= 2 && !Scalars.count
(VF) && "This function should not be visited twice for the same VF"
) ? void (0) : __assert_fail ("VF >= 2 && !Scalars.count(VF) && \"This function should not be visited twice for the same VF\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4171, __extension__ __PRETTY_FUNCTION__))
4171 "This function should not be visited twice for the same VF")(static_cast <bool> (VF >= 2 && !Scalars.count
(VF) && "This function should not be visited twice for the same VF"
) ? void (0) : __assert_fail ("VF >= 2 && !Scalars.count(VF) && \"This function should not be visited twice for the same VF\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4171, __extension__ __PRETTY_FUNCTION__))
;
4172
4173 SmallSetVector<Instruction *, 8> Worklist;
4174
4175 // These sets are used to seed the analysis with pointers used by memory
4176 // accesses that will remain scalar.
4177 SmallSetVector<Instruction *, 8> ScalarPtrs;
4178 SmallPtrSet<Instruction *, 8> PossibleNonScalarPtrs;
4179
4180 // A helper that returns true if the use of Ptr by MemAccess will be scalar.
4181 // The pointer operands of loads and stores will be scalar as long as the
4182 // memory access is not a gather or scatter operation. The value operand of a
4183 // store will remain scalar if the store is scalarized.
4184 auto isScalarUse = [&](Instruction *MemAccess, Value *Ptr) {
4185 InstWidening WideningDecision = getWideningDecision(MemAccess, VF);
4186 assert(WideningDecision != CM_Unknown &&(static_cast <bool> (WideningDecision != CM_Unknown &&
"Widening decision should be ready at this moment") ? void (
0) : __assert_fail ("WideningDecision != CM_Unknown && \"Widening decision should be ready at this moment\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4187, __extension__ __PRETTY_FUNCTION__))
4187 "Widening decision should be ready at this moment")(static_cast <bool> (WideningDecision != CM_Unknown &&
"Widening decision should be ready at this moment") ? void (
0) : __assert_fail ("WideningDecision != CM_Unknown && \"Widening decision should be ready at this moment\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4187, __extension__ __PRETTY_FUNCTION__))
;
4188 if (auto *Store = dyn_cast<StoreInst>(MemAccess))
4189 if (Ptr == Store->getValueOperand())
4190 return WideningDecision == CM_Scalarize;
4191 assert(Ptr == getLoadStorePointerOperand(MemAccess) &&(static_cast <bool> (Ptr == getLoadStorePointerOperand(
MemAccess) && "Ptr is neither a value or pointer operand"
) ? void (0) : __assert_fail ("Ptr == getLoadStorePointerOperand(MemAccess) && \"Ptr is neither a value or pointer operand\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4192, __extension__ __PRETTY_FUNCTION__))
4192 "Ptr is neither a value or pointer operand")(static_cast <bool> (Ptr == getLoadStorePointerOperand(
MemAccess) && "Ptr is neither a value or pointer operand"
) ? void (0) : __assert_fail ("Ptr == getLoadStorePointerOperand(MemAccess) && \"Ptr is neither a value or pointer operand\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4192, __extension__ __PRETTY_FUNCTION__))
;
4193 return WideningDecision != CM_GatherScatter;
4194 };
4195
4196 // A helper that returns true if the given value is a bitcast or
4197 // getelementptr instruction contained in the loop.
4198 auto isLoopVaryingBitCastOrGEP = [&](Value *V) {
4199 return ((isa<BitCastInst>(V) && V->getType()->isPointerTy()) ||
4200 isa<GetElementPtrInst>(V)) &&
4201 !TheLoop->isLoopInvariant(V);
4202 };
4203
4204 // A helper that evaluates a memory access's use of a pointer. If the use
4205 // will be a scalar use, and the pointer is only used by memory accesses, we
4206 // place the pointer in ScalarPtrs. Otherwise, the pointer is placed in
4207 // PossibleNonScalarPtrs.
4208 auto evaluatePtrUse = [&](Instruction *MemAccess, Value *Ptr) {
4209 // We only care about bitcast and getelementptr instructions contained in
4210 // the loop.
4211 if (!isLoopVaryingBitCastOrGEP(Ptr))
4212 return;
4213
4214 // If the pointer has already been identified as scalar (e.g., if it was
4215 // also identified as uniform), there's nothing to do.
4216 auto *I = cast<Instruction>(Ptr);
4217 if (Worklist.count(I))
4218 return;
4219
4220 // If the use of the pointer will be a scalar use, and all users of the
4221 // pointer are memory accesses, place the pointer in ScalarPtrs. Otherwise,
4222 // place the pointer in PossibleNonScalarPtrs.
4223 if (isScalarUse(MemAccess, Ptr) && llvm::all_of(I->users(), [&](User *U) {
4224 return isa<LoadInst>(U) || isa<StoreInst>(U);
4225 }))
4226 ScalarPtrs.insert(I);
4227 else
4228 PossibleNonScalarPtrs.insert(I);
4229 };
4230
4231 // We seed the scalars analysis with three classes of instructions: (1)
4232 // instructions marked uniform-after-vectorization, (2) bitcast and
4233 // getelementptr instructions used by memory accesses requiring a scalar use,
4234 // and (3) pointer induction variables and their update instructions (we
4235 // currently only scalarize these).
4236 //
4237 // (1) Add to the worklist all instructions that have been identified as
4238 // uniform-after-vectorization.
4239 Worklist.insert(Uniforms[VF].begin(), Uniforms[VF].end());
4240
4241 // (2) Add to the worklist all bitcast and getelementptr instructions used by
4242 // memory accesses requiring a scalar use. The pointer operands of loads and
4243 // stores will be scalar as long as the memory accesses is not a gather or
4244 // scatter operation. The value operand of a store will remain scalar if the
4245 // store is scalarized.
4246 for (auto *BB : TheLoop->blocks())
4247 for (auto &I : *BB) {
4248 if (auto *Load = dyn_cast<LoadInst>(&I)) {
4249 evaluatePtrUse(Load, Load->getPointerOperand());
4250 } else if (auto *Store = dyn_cast<StoreInst>(&I)) {
4251 evaluatePtrUse(Store, Store->getPointerOperand());
4252 evaluatePtrUse(Store, Store->getValueOperand());
4253 }
4254 }
4255 for (auto *I : ScalarPtrs)
4256 if (!PossibleNonScalarPtrs.count(I)) {
4257 LLVM_DEBUG(dbgs() << "LV: Found scalar instruction: " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *I << "\n"; } } while (false)
;
4258 Worklist.insert(I);
4259 }
4260
4261 // (3) Add to the worklist all pointer induction variables and their update
4262 // instructions.
4263 //
4264 // TODO: Once we are able to vectorize pointer induction variables we should
4265 // no longer insert them into the worklist here.
4266 auto *Latch = TheLoop->getLoopLatch();
4267 for (auto &Induction : *Legal->getInductionVars()) {
4268 auto *Ind = Induction.first;
4269 auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch));
4270 if (Induction.second.getKind() != InductionDescriptor::IK_PtrInduction)
4271 continue;
4272 Worklist.insert(Ind);
4273 Worklist.insert(IndUpdate);
4274 LLVM_DEBUG(dbgs() << "LV: Found scalar instruction: " << *Ind << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *Ind << "\n"; } } while (false)
;
4275 LLVM_DEBUG(dbgs() << "LV: Found scalar instruction: " << *IndUpdatedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *IndUpdate << "\n"; } } while (false)
4276 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *IndUpdate << "\n"; } } while (false)
;
4277 }
4278
4279 // Insert the forced scalars.
4280 // FIXME: Currently widenPHIInstruction() often creates a dead vector
4281 // induction variable when the PHI user is scalarized.
4282 if (ForcedScalars.count(VF))
4283 for (auto *I : ForcedScalars.find(VF)->second)
4284 Worklist.insert(I);
4285
4286 // Expand the worklist by looking through any bitcasts and getelementptr
4287 // instructions we've already identified as scalar. This is similar to the
4288 // expansion step in collectLoopUniforms(); however, here we're only
4289 // expanding to include additional bitcasts and getelementptr instructions.
4290 unsigned Idx = 0;
4291 while (Idx != Worklist.size()) {
4292 Instruction *Dst = Worklist[Idx++];
4293 if (!isLoopVaryingBitCastOrGEP(Dst->getOperand(0)))
4294 continue;
4295 auto *Src = cast<Instruction>(Dst->getOperand(0));
4296 if (llvm::all_of(Src->users(), [&](User *U) -> bool {
4297 auto *J = cast<Instruction>(U);
4298 return !TheLoop->contains(J) || Worklist.count(J) ||
4299 ((isa<LoadInst>(J) || isa<StoreInst>(J)) &&
4300 isScalarUse(J, Src));
4301 })) {
4302 Worklist.insert(Src);
4303 LLVM_DEBUG(dbgs() << "LV: Found scalar instruction: " << *Src << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *Src << "\n"; } } while (false)
;
4304 }
4305 }
4306
4307 // An induction variable will remain scalar if all users of the induction
4308 // variable and induction variable update remain scalar.
4309 for (auto &Induction : *Legal->getInductionVars()) {
4310 auto *Ind = Induction.first;
4311 auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch));
4312
4313 // We already considered pointer induction variables, so there's no reason
4314 // to look at their users again.
4315 //
4316 // TODO: Once we are able to vectorize pointer induction variables we
4317 // should no longer skip over them here.
4318 if (Induction.second.getKind() == InductionDescriptor::IK_PtrInduction)
4319 continue;
4320
4321 // Determine if all users of the induction variable are scalar after
4322 // vectorization.
4323 auto ScalarInd = llvm::all_of(Ind->users(), [&](User *U) -> bool {
4324 auto *I = cast<Instruction>(U);
4325 return I == IndUpdate || !TheLoop->contains(I) || Worklist.count(I);
4326 });
4327 if (!ScalarInd)
4328 continue;
4329
4330 // Determine if all users of the induction variable update instruction are
4331 // scalar after vectorization.
4332 auto ScalarIndUpdate =
4333 llvm::all_of(IndUpdate->users(), [&](User *U) -> bool {
4334 auto *I = cast<Instruction>(U);
4335 return I == Ind || !TheLoop->contains(I) || Worklist.count(I);
4336 });
4337 if (!ScalarIndUpdate)
4338 continue;
4339
4340 // The induction variable and its update instruction will remain scalar.
4341 Worklist.insert(Ind);
4342 Worklist.insert(IndUpdate);
4343 LLVM_DEBUG(dbgs() << "LV: Found scalar instruction: " << *Ind << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *Ind << "\n"; } } while (false)
;
4344 LLVM_DEBUG(dbgs() << "LV: Found scalar instruction: " << *IndUpdatedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *IndUpdate << "\n"; } } while (false)
4345 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *IndUpdate << "\n"; } } while (false)
;
4346 }
4347
4348 Scalars[VF].insert(Worklist.begin(), Worklist.end());
4349}
4350
4351bool LoopVectorizationCostModel::isScalarWithPredication(Instruction *I) {
4352 if (!Legal->blockNeedsPredication(I->getParent()))
4353 return false;
4354 switch(I->getOpcode()) {
4355 default:
4356 break;
4357 case Instruction::Load:
4358 case Instruction::Store: {
4359 if (!Legal->isMaskRequired(I))
4360 return false;
4361 auto *Ptr = getLoadStorePointerOperand(I);
4362 auto *Ty = getMemInstValueType(I);
4363 return isa<LoadInst>(I) ?
4364 !(isLegalMaskedLoad(Ty, Ptr) || isLegalMaskedGather(Ty))
4365 : !(isLegalMaskedStore(Ty, Ptr) || isLegalMaskedScatter(Ty));
4366 }
4367 case Instruction::UDiv:
4368 case Instruction::SDiv:
4369 case Instruction::SRem:
4370 case Instruction::URem:
4371 return mayDivideByZero(*I);
4372 }
4373 return false;
4374}
4375
4376bool LoopVectorizationCostModel::memoryInstructionCanBeWidened(Instruction *I,
4377 unsigned VF) {
4378 // Get and ensure we have a valid memory instruction.
4379 LoadInst *LI = dyn_cast<LoadInst>(I);
4380 StoreInst *SI = dyn_cast<StoreInst>(I);
4381 assert((LI || SI) && "Invalid memory instruction")(static_cast <bool> ((LI || SI) && "Invalid memory instruction"
) ? void (0) : __assert_fail ("(LI || SI) && \"Invalid memory instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4381, __extension__ __PRETTY_FUNCTION__))
;
4382
4383 auto *Ptr = getLoadStorePointerOperand(I);
4384
4385 // In order to be widened, the pointer should be consecutive, first of all.
4386 if (!Legal->isConsecutivePtr(Ptr))
4387 return false;
4388
4389 // If the instruction is a store located in a predicated block, it will be
4390 // scalarized.
4391 if (isScalarWithPredication(I))
4392 return false;
4393
4394 // If the instruction's allocated size doesn't equal it's type size, it
4395 // requires padding and will be scalarized.
4396 auto &DL = I->getModule()->getDataLayout();
4397 auto *ScalarTy = LI ? LI->getType() : SI->getValueOperand()->getType();
4398 if (hasIrregularType(ScalarTy, DL, VF))
4399 return false;
4400
4401 return true;
4402}
4403
4404void LoopVectorizationCostModel::collectLoopUniforms(unsigned VF) {
4405 // We should not collect Uniforms more than once per VF. Right now,
4406 // this function is called from collectUniformsAndScalars(), which
4407 // already does this check. Collecting Uniforms for VF=1 does not make any
4408 // sense.
4409
4410 assert(VF >= 2 && !Uniforms.count(VF) &&(static_cast <bool> (VF >= 2 && !Uniforms.count
(VF) && "This function should not be visited twice for the same VF"
) ? void (0) : __assert_fail ("VF >= 2 && !Uniforms.count(VF) && \"This function should not be visited twice for the same VF\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4411, __extension__ __PRETTY_FUNCTION__))
4411 "This function should not be visited twice for the same VF")(static_cast <bool> (VF >= 2 && !Uniforms.count
(VF) && "This function should not be visited twice for the same VF"
) ? void (0) : __assert_fail ("VF >= 2 && !Uniforms.count(VF) && \"This function should not be visited twice for the same VF\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4411, __extension__ __PRETTY_FUNCTION__))
;
4412
4413 // Visit the list of Uniforms. If we'll not find any uniform value, we'll
4414 // not analyze again. Uniforms.count(VF) will return 1.
4415 Uniforms[VF].clear();
4416
4417 // We now know that the loop is vectorizable!
4418 // Collect instructions inside the loop that will remain uniform after
4419 // vectorization.
4420
4421 // Global values, params and instructions outside of current loop are out of
4422 // scope.
4423 auto isOutOfScope = [&](Value *V) -> bool {
4424 Instruction *I = dyn_cast<Instruction>(V);
4425 return (!I || !TheLoop->contains(I));
4426 };
4427
4428 SetVector<Instruction *> Worklist;
4429 BasicBlock *Latch = TheLoop->getLoopLatch();
4430
4431 // Start with the conditional branch. If the branch condition is an
4432 // instruction contained in the loop that is only used by the branch, it is
4433 // uniform.
4434 auto *Cmp = dyn_cast<Instruction>(Latch->getTerminator()->getOperand(0));
4435 if (Cmp && TheLoop->contains(Cmp) && Cmp->hasOneUse()) {
4436 Worklist.insert(Cmp);
4437 LLVM_DEBUG(dbgs() << "LV: Found uniform instruction: " << *Cmp << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found uniform instruction: "
<< *Cmp << "\n"; } } while (false)
;
4438 }
4439
4440 // Holds consecutive and consecutive-like pointers. Consecutive-like pointers
4441 // are pointers that are treated like consecutive pointers during
4442 // vectorization. The pointer operands of interleaved accesses are an
4443 // example.
4444 SmallSetVector<Instruction *, 8> ConsecutiveLikePtrs;
4445
4446 // Holds pointer operands of instructions that are possibly non-uniform.
4447 SmallPtrSet<Instruction *, 8> PossibleNonUniformPtrs;
4448
4449 auto isUniformDecision = [&](Instruction *I, unsigned VF) {
4450 InstWidening WideningDecision = getWideningDecision(I, VF);
4451 assert(WideningDecision != CM_Unknown &&(static_cast <bool> (WideningDecision != CM_Unknown &&
"Widening decision should be ready at this moment") ? void (
0) : __assert_fail ("WideningDecision != CM_Unknown && \"Widening decision should be ready at this moment\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4452, __extension__ __PRETTY_FUNCTION__))
4452 "Widening decision should be ready at this moment")(static_cast <bool> (WideningDecision != CM_Unknown &&
"Widening decision should be ready at this moment") ? void (
0) : __assert_fail ("WideningDecision != CM_Unknown && \"Widening decision should be ready at this moment\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4452, __extension__ __PRETTY_FUNCTION__))
;
4453
4454 return (WideningDecision == CM_Widen ||
4455 WideningDecision == CM_Widen_Reverse ||
4456 WideningDecision == CM_Interleave);
4457 };
4458 // Iterate over the instructions in the loop, and collect all
4459 // consecutive-like pointer operands in ConsecutiveLikePtrs. If it's possible
4460 // that a consecutive-like pointer operand will be scalarized, we collect it
4461 // in PossibleNonUniformPtrs instead. We use two sets here because a single
4462 // getelementptr instruction can be used by both vectorized and scalarized
4463 // memory instructions. For example, if a loop loads and stores from the same
4464 // location, but the store is conditional, the store will be scalarized, and
4465 // the getelementptr won't remain uniform.
4466 for (auto *BB : TheLoop->blocks())
4467 for (auto &I : *BB) {
4468 // If there's no pointer operand, there's nothing to do.
4469 auto *Ptr = dyn_cast_or_null<Instruction>(getLoadStorePointerOperand(&I));
4470 if (!Ptr)
4471 continue;
4472
4473 // True if all users of Ptr are memory accesses that have Ptr as their
4474 // pointer operand.
4475 auto UsersAreMemAccesses =
4476 llvm::all_of(Ptr->users(), [&](User *U) -> bool {
4477 return getLoadStorePointerOperand(U) == Ptr;
4478 });
4479
4480 // Ensure the memory instruction will not be scalarized or used by
4481 // gather/scatter, making its pointer operand non-uniform. If the pointer
4482 // operand is used by any instruction other than a memory access, we
4483 // conservatively assume the pointer operand may be non-uniform.
4484 if (!UsersAreMemAccesses || !isUniformDecision(&I, VF))
4485 PossibleNonUniformPtrs.insert(Ptr);
4486
4487 // If the memory instruction will be vectorized and its pointer operand
4488 // is consecutive-like, or interleaving - the pointer operand should
4489 // remain uniform.
4490 else
4491 ConsecutiveLikePtrs.insert(Ptr);
4492 }
4493
4494 // Add to the Worklist all consecutive and consecutive-like pointers that
4495 // aren't also identified as possibly non-uniform.
4496 for (auto *V : ConsecutiveLikePtrs)
4497 if (!PossibleNonUniformPtrs.count(V)) {
4498 LLVM_DEBUG(dbgs() << "LV: Found uniform instruction: " << *V << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found uniform instruction: "
<< *V << "\n"; } } while (false)
;
4499 Worklist.insert(V);
4500 }
4501
4502 // Expand Worklist in topological order: whenever a new instruction
4503 // is added , its users should be either already inside Worklist, or
4504 // out of scope. It ensures a uniform instruction will only be used
4505 // by uniform instructions or out of scope instructions.
4506 unsigned idx = 0;
4507 while (idx != Worklist.size()) {
4508 Instruction *I = Worklist[idx++];
4509
4510 for (auto OV : I->operand_values()) {
4511 if (isOutOfScope(OV))
4512 continue;
4513 auto *OI = cast<Instruction>(OV);
4514 if (llvm::all_of(OI->users(), [&](User *U) -> bool {
4515 auto *J = cast<Instruction>(U);
4516 return !TheLoop->contains(J) || Worklist.count(J) ||
4517 (OI == getLoadStorePointerOperand(J) &&
4518 isUniformDecision(J, VF));
4519 })) {
4520 Worklist.insert(OI);
4521 LLVM_DEBUG(dbgs() << "LV: Found uniform instruction: " << *OI << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found uniform instruction: "
<< *OI << "\n"; } } while (false)
;
4522 }
4523 }
4524 }
4525
4526 // Returns true if Ptr is the pointer operand of a memory access instruction
4527 // I, and I is known to not require scalarization.
4528 auto isVectorizedMemAccessUse = [&](Instruction *I, Value *Ptr) -> bool {
4529 return getLoadStorePointerOperand(I) == Ptr && isUniformDecision(I, VF);
4530 };
4531
4532 // For an instruction to be added into Worklist above, all its users inside
4533 // the loop should also be in Worklist. However, this condition cannot be
4534 // true for phi nodes that form a cyclic dependence. We must process phi
4535 // nodes separately. An induction variable will remain uniform if all users
4536 // of the induction variable and induction variable update remain uniform.
4537 // The code below handles both pointer and non-pointer induction variables.
4538 for (auto &Induction : *Legal->getInductionVars()) {
4539 auto *Ind = Induction.first;
4540 auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch));
4541
4542 // Determine if all users of the induction variable are uniform after
4543 // vectorization.
4544 auto UniformInd = llvm::all_of(Ind->users(), [&](User *U) -> bool {
4545 auto *I = cast<Instruction>(U);
4546 return I == IndUpdate || !TheLoop->contains(I) || Worklist.count(I) ||
4547 isVectorizedMemAccessUse(I, Ind);
4548 });
4549 if (!UniformInd)
4550 continue;
4551
4552 // Determine if all users of the induction variable update instruction are
4553 // uniform after vectorization.
4554 auto UniformIndUpdate =
4555 llvm::all_of(IndUpdate->users(), [&](User *U) -> bool {
4556 auto *I = cast<Instruction>(U);
4557 return I == Ind || !TheLoop->contains(I) || Worklist.count(I) ||
4558 isVectorizedMemAccessUse(I, IndUpdate);
4559 });
4560 if (!UniformIndUpdate)
4561 continue;
4562
4563 // The induction variable and its update instruction will remain uniform.
4564 Worklist.insert(Ind);
4565 Worklist.insert(IndUpdate);
4566 LLVM_DEBUG(dbgs() << "LV: Found uniform instruction: " << *Ind << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found uniform instruction: "
<< *Ind << "\n"; } } while (false)
;
4567 LLVM_DEBUG(dbgs() << "LV: Found uniform instruction: " << *IndUpdatedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found uniform instruction: "
<< *IndUpdate << "\n"; } } while (false)
4568 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found uniform instruction: "
<< *IndUpdate << "\n"; } } while (false)
;
4569 }
4570
4571 Uniforms[VF].insert(Worklist.begin(), Worklist.end());
4572}
4573
4574void InterleavedAccessInfo::collectConstStrideAccesses(
4575 MapVector<Instruction *, StrideDescriptor> &AccessStrideInfo,
4576 const ValueToValueMap &Strides) {
4577 auto &DL = TheLoop->getHeader()->getModule()->getDataLayout();
4578
4579 // Since it's desired that the load/store instructions be maintained in
4580 // "program order" for the interleaved access analysis, we have to visit the
4581 // blocks in the loop in reverse postorder (i.e., in a topological order).
4582 // Such an ordering will ensure that any load/store that may be executed
4583 // before a second load/store will precede the second load/store in
4584 // AccessStrideInfo.
4585 LoopBlocksDFS DFS(TheLoop);
4586 DFS.perform(LI);
4587 for (BasicBlock *BB : make_range(DFS.beginRPO(), DFS.endRPO()))
4588 for (auto &I : *BB) {
4589 auto *LI = dyn_cast<LoadInst>(&I);
4590 auto *SI = dyn_cast<StoreInst>(&I);
4591 if (!LI && !SI)
4592 continue;
4593
4594 Value *Ptr = getLoadStorePointerOperand(&I);
4595 // We don't check wrapping here because we don't know yet if Ptr will be
4596 // part of a full group or a group with gaps. Checking wrapping for all
4597 // pointers (even those that end up in groups with no gaps) will be overly
4598 // conservative. For full groups, wrapping should be ok since if we would
4599 // wrap around the address space we would do a memory access at nullptr
4600 // even without the transformation. The wrapping checks are therefore
4601 // deferred until after we've formed the interleaved groups.
4602 int64_t Stride = getPtrStride(PSE, Ptr, TheLoop, Strides,
4603 /*Assume=*/true, /*ShouldCheckWrap=*/false);
4604
4605 const SCEV *Scev = replaceSymbolicStrideSCEV(PSE, Strides, Ptr);
4606 PointerType *PtrTy = dyn_cast<PointerType>(Ptr->getType());
4607 uint64_t Size = DL.getTypeAllocSize(PtrTy->getElementType());
4608
4609 // An alignment of 0 means target ABI alignment.
4610 unsigned Align = getMemInstAlignment(&I);
4611 if (!Align)
4612 Align = DL.getABITypeAlignment(PtrTy->getElementType());
4613
4614 AccessStrideInfo[&I] = StrideDescriptor(Stride, Scev, Size, Align);
4615 }
4616}
4617
4618// Analyze interleaved accesses and collect them into interleaved load and
4619// store groups.
4620//
4621// When generating code for an interleaved load group, we effectively hoist all
4622// loads in the group to the location of the first load in program order. When
4623// generating code for an interleaved store group, we sink all stores to the
4624// location of the last store. This code motion can change the order of load
4625// and store instructions and may break dependences.
4626//
4627// The code generation strategy mentioned above ensures that we won't violate
4628// any write-after-read (WAR) dependences.
4629//
4630// E.g., for the WAR dependence: a = A[i]; // (1)
4631// A[i] = b; // (2)
4632//
4633// The store group of (2) is always inserted at or below (2), and the load
4634// group of (1) is always inserted at or above (1). Thus, the instructions will
4635// never be reordered. All other dependences are checked to ensure the
4636// correctness of the instruction reordering.
4637//
4638// The algorithm visits all memory accesses in the loop in bottom-up program
4639// order. Program order is established by traversing the blocks in the loop in
4640// reverse postorder when collecting the accesses.
4641//
4642// We visit the memory accesses in bottom-up order because it can simplify the
4643// construction of store groups in the presence of write-after-write (WAW)
4644// dependences.
4645//
4646// E.g., for the WAW dependence: A[i] = a; // (1)
4647// A[i] = b; // (2)
4648// A[i + 1] = c; // (3)
4649//
4650// We will first create a store group with (3) and (2). (1) can't be added to
4651// this group because it and (2) are dependent. However, (1) can be grouped
4652// with other accesses that may precede it in program order. Note that a
4653// bottom-up order does not imply that WAW dependences should not be checked.
4654void InterleavedAccessInfo::analyzeInterleaving() {
4655 LLVM_DEBUG(dbgs() << "LV: Analyzing interleaved accesses...\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Analyzing interleaved accesses...\n"
; } } while (false)
;
4656 const ValueToValueMap &Strides = LAI->getSymbolicStrides();
4657
4658 // Holds all accesses with a constant stride.
4659 MapVector<Instruction *, StrideDescriptor> AccessStrideInfo;
4660 collectConstStrideAccesses(AccessStrideInfo, Strides);
4661
4662 if (AccessStrideInfo.empty())
1
Assuming the condition is false
2
Taking false branch
4663 return;
4664
4665 // Collect the dependences in the loop.
4666 collectDependences();
4667
4668 // Holds all interleaved store groups temporarily.
4669 SmallSetVector<InterleaveGroup *, 4> StoreGroups;
4670 // Holds all interleaved load groups temporarily.
4671 SmallSetVector<InterleaveGroup *, 4> LoadGroups;
4672
4673 // Search in bottom-up program order for pairs of accesses (A and B) that can
4674 // form interleaved load or store groups. In the algorithm below, access A
4675 // precedes access B in program order. We initialize a group for B in the
4676 // outer loop of the algorithm, and then in the inner loop, we attempt to
4677 // insert each A into B's group if:
4678 //
4679 // 1. A and B have the same stride,
4680 // 2. A and B have the same memory object size, and
4681 // 3. A belongs in B's group according to its distance from B.
4682 //
4683 // Special care is taken to ensure group formation will not break any
4684 // dependences.
4685 for (auto BI = AccessStrideInfo.rbegin(), E = AccessStrideInfo.rend();
3
Loop condition is true. Entering loop body
4686 BI != E; ++BI) {
4687 Instruction *B = BI->first;
4688 StrideDescriptor DesB = BI->second;
4689
4690 // Initialize a group for B if it has an allowable stride. Even if we don't
4691 // create a group for B, we continue with the bottom-up algorithm to ensure
4692 // we don't break any of B's dependences.
4693 InterleaveGroup *Group = nullptr;
4
'Group' initialized to a null pointer value
4694 if (isStrided(DesB.Stride)) {
5
Taking false branch
4695 Group = getInterleaveGroup(B);
4696 if (!Group) {
4697 LLVM_DEBUG(dbgs() << "LV: Creating an interleave group with:" << *Bdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Creating an interleave group with:"
<< *B << '\n'; } } while (false)
4698 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Creating an interleave group with:"
<< *B << '\n'; } } while (false)
;
4699 Group = createInterleaveGroup(B, DesB.Stride, DesB.Align);
4700 }
4701 if (B->mayWriteToMemory())
4702 StoreGroups.insert(Group);
4703 else
4704 LoadGroups.insert(Group);
4705 }
4706
4707 for (auto AI = std::next(BI); AI != E; ++AI) {
6
Loop condition is true. Entering loop body
4708 Instruction *A = AI->first;
4709 StrideDescriptor DesA = AI->second;
4710
4711 // Our code motion strategy implies that we can't have dependences
4712 // between accesses in an interleaved group and other accesses located
4713 // between the first and last member of the group. Note that this also
4714 // means that a group can't have more than one member at a given offset.
4715 // The accesses in a group can have dependences with other accesses, but
4716 // we must ensure we don't extend the boundaries of the group such that
4717 // we encompass those dependent accesses.
4718 //
4719 // For example, assume we have the sequence of accesses shown below in a
4720 // stride-2 loop:
4721 //
4722 // (1, 2) is a group | A[i] = a; // (1)
4723 // | A[i-1] = b; // (2) |
4724 // A[i-3] = c; // (3)
4725 // A[i] = d; // (4) | (2, 4) is not a group
4726 //
4727 // Because accesses (2) and (3) are dependent, we can group (2) with (1)
4728 // but not with (4). If we did, the dependent access (3) would be within
4729 // the boundaries of the (2, 4) group.
4730 if (!canReorderMemAccessesForInterleavedGroups(&*AI, &*BI)) {
7
Taking false branch
4731 // If a dependence exists and A is already in a group, we know that A
4732 // must be a store since A precedes B and WAR dependences are allowed.
4733 // Thus, A would be sunk below B. We release A's group to prevent this
4734 // illegal code motion. A will then be free to form another group with
4735 // instructions that precede it.
4736 if (isInterleaved(A)) {
4737 InterleaveGroup *StoreGroup = getInterleaveGroup(A);
4738 StoreGroups.remove(StoreGroup);
4739 releaseGroup(StoreGroup);
4740 }
4741
4742 // If a dependence exists and A is not already in a group (or it was
4743 // and we just released it), B might be hoisted above A (if B is a
4744 // load) or another store might be sunk below A (if B is a store). In
4745 // either case, we can't add additional instructions to B's group. B
4746 // will only form a group with instructions that it precedes.
4747 break;
4748 }
4749
4750 // At this point, we've checked for illegal code motion. If either A or B
4751 // isn't strided, there's nothing left to do.
4752 if (!isStrided(DesA.Stride) || !isStrided(DesB.Stride))
8
Taking false branch
4753 continue;
4754
4755 // Ignore A if it's already in a group or isn't the same kind of memory
4756 // operation as B.
4757 // Note that mayReadFromMemory() isn't mutually exclusive to mayWriteToMemory
4758 // in the case of atomic loads. We shouldn't see those here, canVectorizeMemory()
4759 // should have returned false - except for the case we asked for optimization
4760 // remarks.
4761 if (isInterleaved(A) || (A->mayReadFromMemory() != B->mayReadFromMemory())
9
Assuming the condition is false
10
Assuming the condition is false
12
Taking false branch
4762 || (A->mayWriteToMemory() != B->mayWriteToMemory()))
11
Assuming the condition is false
4763 continue;
4764
4765 // Check rules 1 and 2. Ignore A if its stride or size is different from
4766 // that of B.
4767 if (DesA.Stride != DesB.Stride || DesA.Size != DesB.Size)
13
Assuming the condition is false
14
Assuming the condition is false
15
Taking false branch
4768 continue;
4769
4770 // Ignore A if the memory object of A and B don't belong to the same
4771 // address space
4772 if (getMemInstAddressSpace(A) != getMemInstAddressSpace(B))
16
Assuming the condition is false
17
Taking false branch
4773 continue;
4774
4775 // Calculate the distance from A to B.
4776 const SCEVConstant *DistToB = dyn_cast<SCEVConstant>(
4777 PSE.getSE()->getMinusSCEV(DesA.Scev, DesB.Scev));
4778 if (!DistToB)
18
Assuming 'DistToB' is non-null
19
Taking false branch
4779 continue;
4780 int64_t DistanceToB = DistToB->getAPInt().getSExtValue();
4781
4782 // Check rule 3. Ignore A if its distance to B is not a multiple of the
4783 // size.
4784 if (DistanceToB % static_cast<int64_t>(DesB.Size))
20
Assuming the condition is false
21
Taking false branch
4785 continue;
4786
4787 // Ignore A if either A or B is in a predicated block. Although we
4788 // currently prevent group formation for predicated accesses, we may be
4789 // able to relax this limitation in the future once we handle more
4790 // complicated blocks.
4791 if (isPredicated(A->getParent()) || isPredicated(B->getParent()))
22
Assuming the condition is false
23
Assuming the condition is false
24
Taking false branch
4792 continue;
4793
4794 // The index of A is the index of B plus A's distance to B in multiples
4795 // of the size.
4796 int IndexA =
4797 Group->getIndex(B) + DistanceToB / static_cast<int64_t>(DesB.Size);
25
Called C++ object pointer is null
4798
4799 // Try to insert A into B's group.
4800 if (Group->insertMember(A, IndexA, DesA.Align)) {
4801 LLVM_DEBUG(dbgs() << "LV: Inserted:" << *A << '\n'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Inserted:" <<
*A << '\n' << " into the interleave group with"
<< *B << '\n'; } } while (false)
4802 << " into the interleave group with" << *Bdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Inserted:" <<
*A << '\n' << " into the interleave group with"
<< *B << '\n'; } } while (false)
4803 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Inserted:" <<
*A << '\n' << " into the interleave group with"
<< *B << '\n'; } } while (false)
;
4804 InterleaveGroupMap[A] = Group;
4805
4806 // Set the first load in program order as the insert position.
4807 if (A->mayReadFromMemory())
4808 Group->setInsertPos(A);
4809 }
4810 } // Iteration over A accesses.
4811 } // Iteration over B accesses.
4812
4813 // Remove interleaved store groups with gaps.
4814 for (InterleaveGroup *Group : StoreGroups)
4815 if (Group->getNumMembers() != Group->getFactor()) {
4816 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved store group due "
"to gaps.\n"; } } while (false)
4817 dbgs() << "LV: Invalidate candidate interleaved store group due "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved store group due "
"to gaps.\n"; } } while (false)
4818 "to gaps.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved store group due "
"to gaps.\n"; } } while (false)
;
4819 releaseGroup(Group);
4820 }
4821 // Remove interleaved groups with gaps (currently only loads) whose memory
4822 // accesses may wrap around. We have to revisit the getPtrStride analysis,
4823 // this time with ShouldCheckWrap=true, since collectConstStrideAccesses does
4824 // not check wrapping (see documentation there).
4825 // FORNOW we use Assume=false;
4826 // TODO: Change to Assume=true but making sure we don't exceed the threshold
4827 // of runtime SCEV assumptions checks (thereby potentially failing to
4828 // vectorize altogether).
4829 // Additional optional optimizations:
4830 // TODO: If we are peeling the loop and we know that the first pointer doesn't
4831 // wrap then we can deduce that all pointers in the group don't wrap.
4832 // This means that we can forcefully peel the loop in order to only have to
4833 // check the first pointer for no-wrap. When we'll change to use Assume=true
4834 // we'll only need at most one runtime check per interleaved group.
4835 for (InterleaveGroup *Group : LoadGroups) {
4836 // Case 1: A full group. Can Skip the checks; For full groups, if the wide
4837 // load would wrap around the address space we would do a memory access at
4838 // nullptr even without the transformation.
4839 if (Group->getNumMembers() == Group->getFactor())
4840 continue;
4841
4842 // Case 2: If first and last members of the group don't wrap this implies
4843 // that all the pointers in the group don't wrap.
4844 // So we check only group member 0 (which is always guaranteed to exist),
4845 // and group member Factor - 1; If the latter doesn't exist we rely on
4846 // peeling (if it is a non-reveresed accsess -- see Case 3).
4847 Value *FirstMemberPtr = getLoadStorePointerOperand(Group->getMember(0));
4848 if (!getPtrStride(PSE, FirstMemberPtr, TheLoop, Strides, /*Assume=*/false,
4849 /*ShouldCheckWrap=*/true)) {
4850 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"first group member potentially pointer-wrapping.\n"; } } while
(false)
4851 dbgs() << "LV: Invalidate candidate interleaved group due to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"first group member potentially pointer-wrapping.\n"; } } while
(false)
4852 "first group member potentially pointer-wrapping.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"first group member potentially pointer-wrapping.\n"; } } while
(false)
;
4853 releaseGroup(Group);
4854 continue;
4855 }
4856 Instruction *LastMember = Group->getMember(Group->getFactor() - 1);
4857 if (LastMember) {
4858 Value *LastMemberPtr = getLoadStorePointerOperand(LastMember);
4859 if (!getPtrStride(PSE, LastMemberPtr, TheLoop, Strides, /*Assume=*/false,
4860 /*ShouldCheckWrap=*/true)) {
4861 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"last group member potentially pointer-wrapping.\n"; } } while
(false)
4862 dbgs() << "LV: Invalidate candidate interleaved group due to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"last group member potentially pointer-wrapping.\n"; } } while
(false)
4863 "last group member potentially pointer-wrapping.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"last group member potentially pointer-wrapping.\n"; } } while
(false)
;
4864 releaseGroup(Group);
4865 }
4866 } else {
4867 // Case 3: A non-reversed interleaved load group with gaps: We need
4868 // to execute at least one scalar epilogue iteration. This will ensure
4869 // we don't speculatively access memory out-of-bounds. We only need
4870 // to look for a member at index factor - 1, since every group must have
4871 // a member at index zero.
4872 if (Group->isReverse()) {
4873 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"a reverse access with gaps.\n"; } } while (false)
4874 dbgs() << "LV: Invalidate candidate interleaved group due to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"a reverse access with gaps.\n"; } } while (false)
4875 "a reverse access with gaps.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"a reverse access with gaps.\n"; } } while (false)
;
4876 releaseGroup(Group);
4877 continue;
4878 }
4879 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaved group requires epilogue iteration.\n"
; } } while (false)
4880 dbgs() << "LV: Interleaved group requires epilogue iteration.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaved group requires epilogue iteration.\n"
; } } while (false)
;
4881 RequiresScalarEpilogue = true;
4882 }
4883 }
4884}
4885
4886Optional<unsigned> LoopVectorizationCostModel::computeMaxVF(bool OptForSize) {
4887 if (Legal->getRuntimePointerChecking()->Need && TTI.hasBranchDivergence()) {
4888 // TODO: It may by useful to do since it's still likely to be dynamically
4889 // uniform if the target can skip.
4890 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not inserting runtime ptr check for divergent target"
; } } while (false)
4891 dbgs() << "LV: Not inserting runtime ptr check for divergent target")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not inserting runtime ptr check for divergent target"
; } } while (false)
;
4892
4893 ORE->emit(
4894 createMissedAnalysis("CantVersionLoopWithDivergentTarget")
4895 << "runtime pointer checks needed. Not enabled for divergent target");
4896
4897 return None;
4898 }
4899
4900 unsigned TC = PSE.getSE()->getSmallConstantTripCount(TheLoop);
4901 if (!OptForSize) // Remaining checks deal with scalar loop when OptForSize.
4902 return computeFeasibleMaxVF(OptForSize, TC);
4903
4904 if (Legal->getRuntimePointerChecking()->Need) {
4905 ORE->emit(createMissedAnalysis("CantVersionLoopWithOptForSize")
4906 << "runtime pointer checks needed. Enable vectorization of this "
4907 "loop with '#pragma clang loop vectorize(enable)' when "
4908 "compiling with -Os/-Oz");
4909 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. Runtime ptr check is required with -Os/-Oz.\n"
; } } while (false)
4910 dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. Runtime ptr check is required with -Os/-Oz.\n"
; } } while (false)
4911 << "LV: Aborting. Runtime ptr check is required with -Os/-Oz.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. Runtime ptr check is required with -Os/-Oz.\n"
; } } while (false)
;
4912 return None;
4913 }
4914
4915 // If we optimize the program for size, avoid creating the tail loop.
4916 LLVM_DEBUG(dbgs() << "LV: Found trip count: " << TC << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found trip count: "
<< TC << '\n'; } } while (false)
;
4917
4918 // If we don't know the precise trip count, don't try to vectorize.
4919 if (TC < 2) {
4920 ORE->emit(
4921 createMissedAnalysis("UnknownLoopCountComplexCFG")
4922 << "unable to calculate the loop count due to complex control flow");
4923 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n"
; } } while (false)
4924 dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n"
; } } while (false)
;
4925 return None;
4926 }
4927
4928 unsigned MaxVF = computeFeasibleMaxVF(OptForSize, TC);
4929
4930 if (TC % MaxVF != 0) {
4931 // If the trip count that we found modulo the vectorization factor is not
4932 // zero then we require a tail.
4933 // FIXME: look for a smaller MaxVF that does divide TC rather than give up.
4934 // FIXME: return None if loop requiresScalarEpilog(<MaxVF>), or look for a
4935 // smaller MaxVF that does not require a scalar epilog.
4936
4937 ORE->emit(createMissedAnalysis("NoTailLoopWithOptForSize")
4938 << "cannot optimize for size and vectorize at the "
4939 "same time. Enable vectorization of this loop "
4940 "with '#pragma clang loop vectorize(enable)' "
4941 "when compiling with -Os/-Oz");
4942 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n"
; } } while (false)
4943 dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n"
; } } while (false)
;
4944 return None;
4945 }
4946
4947 return MaxVF;
4948}
4949
4950unsigned
4951LoopVectorizationCostModel::computeFeasibleMaxVF(bool OptForSize,
4952 unsigned ConstTripCount) {
4953 MinBWs = computeMinimumValueSizes(TheLoop->getBlocks(), *DB, &TTI);
4954 unsigned SmallestType, WidestType;
4955 std::tie(SmallestType, WidestType) = getSmallestAndWidestTypes();
4956 unsigned WidestRegister = TTI.getRegisterBitWidth(true);
4957
4958 // Get the maximum safe dependence distance in bits computed by LAA.
4959 // It is computed by MaxVF * sizeOf(type) * 8, where type is taken from
4960 // the memory accesses that is most restrictive (involved in the smallest
4961 // dependence distance).
4962 unsigned MaxSafeRegisterWidth = Legal->getMaxSafeRegisterWidth();
4963
4964 WidestRegister = std::min(WidestRegister, MaxSafeRegisterWidth);
4965
4966 unsigned MaxVectorSize = WidestRegister / WidestType;
4967
4968 LLVM_DEBUG(dbgs() << "LV: The Smallest and Widest types: " << SmallestTypedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Smallest and Widest types: "
<< SmallestType << " / " << WidestType <<
" bits.\n"; } } while (false)
4969 << " / " << WidestType << " bits.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Smallest and Widest types: "
<< SmallestType << " / " << WidestType <<
" bits.\n"; } } while (false)
;
4970 LLVM_DEBUG(dbgs() << "LV: The Widest register safe to use is: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Widest register safe to use is: "
<< WidestRegister << " bits.\n"; } } while (false
)
4971 << WidestRegister << " bits.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Widest register safe to use is: "
<< WidestRegister << " bits.\n"; } } while (false
)
;
4972
4973 assert(MaxVectorSize <= 256 && "Did not expect to pack so many elements"(static_cast <bool> (MaxVectorSize <= 256 &&
"Did not expect to pack so many elements" " into one vector!"
) ? void (0) : __assert_fail ("MaxVectorSize <= 256 && \"Did not expect to pack so many elements\" \" into one vector!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4974, __extension__ __PRETTY_FUNCTION__))
4974 " into one vector!")(static_cast <bool> (MaxVectorSize <= 256 &&
"Did not expect to pack so many elements" " into one vector!"
) ? void (0) : __assert_fail ("MaxVectorSize <= 256 && \"Did not expect to pack so many elements\" \" into one vector!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4974, __extension__ __PRETTY_FUNCTION__))
;
4975 if (MaxVectorSize == 0) {
4976 LLVM_DEBUG(dbgs() << "LV: The target has no vector registers.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The target has no vector registers.\n"
; } } while (false)
;
4977 MaxVectorSize = 1;
4978 return MaxVectorSize;
4979 } else if (ConstTripCount && ConstTripCount < MaxVectorSize &&
4980 isPowerOf2_32(ConstTripCount)) {
4981 // We need to clamp the VF to be the ConstTripCount. There is no point in
4982 // choosing a higher viable VF as done in the loop below.
4983 LLVM_DEBUG(dbgs() << "LV: Clamping the MaxVF to the constant trip count: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Clamping the MaxVF to the constant trip count: "
<< ConstTripCount << "\n"; } } while (false)
4984 << ConstTripCount << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Clamping the MaxVF to the constant trip count: "
<< ConstTripCount << "\n"; } } while (false)
;
4985 MaxVectorSize = ConstTripCount;
4986 return MaxVectorSize;
4987 }
4988
4989 unsigned MaxVF = MaxVectorSize;
4990 if (TTI.shouldMaximizeVectorBandwidth(OptForSize) ||
4991 (MaximizeBandwidth && !OptForSize)) {
4992 // Collect all viable vectorization factors larger than the default MaxVF
4993 // (i.e. MaxVectorSize).
4994 SmallVector<unsigned, 8> VFs;
4995 unsigned NewMaxVectorSize = WidestRegister / SmallestType;
4996 for (unsigned VS = MaxVectorSize * 2; VS <= NewMaxVectorSize; VS *= 2)
4997 VFs.push_back(VS);
4998
4999 // For each VF calculate its register usage.
5000 auto RUs = calculateRegisterUsage(VFs);
5001
5002 // Select the largest VF which doesn't require more registers than existing
5003 // ones.
5004 unsigned TargetNumRegisters = TTI.getNumberOfRegisters(true);
5005 for (int i = RUs.size() - 1; i >= 0; --i) {
5006 if (RUs[i].MaxLocalUsers <= TargetNumRegisters) {
5007 MaxVF = VFs[i];
5008 break;
5009 }
5010 }
5011 if (unsigned MinVF = TTI.getMinimumVF(SmallestType)) {
5012 if (MaxVF < MinVF) {
5013 LLVM_DEBUG(dbgs() << "LV: Overriding calculated MaxVF(" << MaxVFdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Overriding calculated MaxVF("
<< MaxVF << ") with target's minimum: " <<
MinVF << '\n'; } } while (false)
5014 << ") with target's minimum: " << MinVF << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Overriding calculated MaxVF("
<< MaxVF << ") with target's minimum: " <<
MinVF << '\n'; } } while (false)
;
5015 MaxVF = MinVF;
5016 }
5017 }
5018 }
5019 return MaxVF;
5020}
5021
5022VectorizationFactor
5023LoopVectorizationCostModel::selectVectorizationFactor(unsigned MaxVF) {
5024 float Cost = expectedCost(1).first;
5025 const float ScalarCost = Cost;
5026 unsigned Width = 1;
5027 LLVM_DEBUG(dbgs() << "LV: Scalar loop costs: " << (int)ScalarCost << ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Scalar loop costs: "
<< (int)ScalarCost << ".\n"; } } while (false)
;
5028
5029 bool ForceVectorization = Hints->getForce() == LoopVectorizeHints::FK_Enabled;
5030 if (ForceVectorization && MaxVF > 1) {
5031 // Ignore scalar width, because the user explicitly wants vectorization.
5032 // Initialize cost to max so that VF = 2 is, at least, chosen during cost
5033 // evaluation.
5034 Cost = std::numeric_limits<float>::max();
5035 }
5036
5037 for (unsigned i = 2; i <= MaxVF; i *= 2) {
5038 // Notice that the vector loop needs to be executed less times, so
5039 // we need to divide the cost of the vector loops by the width of
5040 // the vector elements.
5041 VectorizationCostTy C = expectedCost(i);
5042 float VectorCost = C.first / (float)i;
5043 LLVM_DEBUG(dbgs() << "LV: Vector loop of width " << ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Vector loop of width "
<< i << " costs: " << (int)VectorCost <<
".\n"; } } while (false)
5044 << " costs: " << (int)VectorCost << ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Vector loop of width "
<< i << " costs: " << (int)VectorCost <<
".\n"; } } while (false)
;
5045 if (!C.second && !ForceVectorization) {
5046 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not considering vector loop of width "
<< i << " because it will not generate any vector instructions.\n"
; } } while (false)
5047 dbgs() << "LV: Not considering vector loop of width " << ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not considering vector loop of width "
<< i << " because it will not generate any vector instructions.\n"
; } } while (false)
5048 << " because it will not generate any vector instructions.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not considering vector loop of width "
<< i << " because it will not generate any vector instructions.\n"
; } } while (false)
;
5049 continue;
5050 }
5051 if (VectorCost < Cost) {
5052 Cost = VectorCost;
5053 Width = i;
5054 }
5055 }
5056
5057 if (!EnableCondStoresVectorization && NumPredStores) {
5058 ORE->emit(createMissedAnalysis("ConditionalStore")
5059 << "store that is conditionally executed prevents vectorization");
5060 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: No vectorization. There are conditional stores.\n"
; } } while (false)
5061 dbgs() << "LV: No vectorization. There are conditional stores.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: No vectorization. There are conditional stores.\n"
; } } while (false)
;
5062 Width = 1;
5063 Cost = ScalarCost;
5064 }
5065
5066 LLVM_DEBUG(if (ForceVectorization && Width > 1 && Cost >= ScalarCost) dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (ForceVectorization && Width
> 1 && Cost >= ScalarCost) dbgs() << "LV: Vectorization seems to be not beneficial, "
<< "but was forced by a user.\n"; } } while (false)
5067 << "LV: Vectorization seems to be not beneficial, "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (ForceVectorization && Width
> 1 && Cost >= ScalarCost) dbgs() << "LV: Vectorization seems to be not beneficial, "
<< "but was forced by a user.\n"; } } while (false)
5068 << "but was forced by a user.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (ForceVectorization && Width
> 1 && Cost >= ScalarCost) dbgs() << "LV: Vectorization seems to be not beneficial, "
<< "but was forced by a user.\n"; } } while (false)
;
5069 LLVM_DEBUG(dbgs() << "LV: Selecting VF: " << Width << ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Selecting VF: " <<
Width << ".\n"; } } while (false)
;
5070 VectorizationFactor Factor = {Width, (unsigned)(Width * Cost)};
5071 return Factor;
5072}
5073
5074std::pair<unsigned, unsigned>
5075LoopVectorizationCostModel::getSmallestAndWidestTypes() {
5076 unsigned MinWidth = -1U;
5077 unsigned MaxWidth = 8;
5078 const DataLayout &DL = TheFunction->getParent()->getDataLayout();
5079
5080 // For each block.
5081 for (BasicBlock *BB : TheLoop->blocks()) {
5082 // For each instruction in the loop.
5083 for (Instruction &I : *BB) {
5084 Type *T = I.getType();
5085
5086 // Skip ignored values.
5087 if (ValuesToIgnore.count(&I))
5088 continue;
5089
5090 // Only examine Loads, Stores and PHINodes.
5091 if (!isa<LoadInst>(I) && !isa<StoreInst>(I) && !isa<PHINode>(I))
5092 continue;
5093
5094 // Examine PHI nodes that are reduction variables. Update the type to
5095 // account for the recurrence type.
5096 if (auto *PN = dyn_cast<PHINode>(&I)) {
5097 if (!Legal->isReductionVariable(PN))
5098 continue;
5099 RecurrenceDescriptor RdxDesc = (*Legal->getReductionVars())[PN];
5100 T = RdxDesc.getRecurrenceType();
5101 }
5102
5103 // Examine the stored values.
5104 if (auto *ST = dyn_cast<StoreInst>(&I))
5105 T = ST->getValueOperand()->getType();
5106
5107 // Ignore loaded pointer types and stored pointer types that are not
5108 // vectorizable.
5109 //
5110 // FIXME: The check here attempts to predict whether a load or store will
5111 // be vectorized. We only know this for certain after a VF has
5112 // been selected. Here, we assume that if an access can be
5113 // vectorized, it will be. We should also look at extending this
5114 // optimization to non-pointer types.
5115 //
5116 if (T->isPointerTy() && !isConsecutiveLoadOrStore(&I) &&
5117 !isAccessInterleaved(&I) && !isLegalGatherOrScatter(&I))
5118 continue;
5119
5120 MinWidth = std::min(MinWidth,
5121 (unsigned)DL.getTypeSizeInBits(T->getScalarType()));
5122 MaxWidth = std::max(MaxWidth,
5123 (unsigned)DL.getTypeSizeInBits(T->getScalarType()));
5124 }
5125 }
5126
5127 return {MinWidth, MaxWidth};
5128}
5129
5130unsigned LoopVectorizationCostModel::selectInterleaveCount(bool OptForSize,
5131 unsigned VF,
5132 unsigned LoopCost) {
5133 // -- The interleave heuristics --
5134 // We interleave the loop in order to expose ILP and reduce the loop overhead.
5135 // There are many micro-architectural considerations that we can't predict
5136 // at this level. For example, frontend pressure (on decode or fetch) due to
5137 // code size, or the number and capabilities of the execution ports.
5138 //
5139 // We use the following heuristics to select the interleave count:
5140 // 1. If the code has reductions, then we interleave to break the cross
5141 // iteration dependency.
5142 // 2. If the loop is really small, then we interleave to reduce the loop
5143 // overhead.
5144 // 3. We don't interleave if we think that we will spill registers to memory
5145 // due to the increased register pressure.
5146
5147 // When we optimize for size, we don't interleave.
5148 if (OptForSize)
5149 return 1;
5150
5151 // We used the distance for the interleave count.
5152 if (Legal->getMaxSafeDepDistBytes() != -1U)
5153 return 1;
5154
5155 // Do not interleave loops with a relatively small trip count.
5156 unsigned TC = PSE.getSE()->getSmallConstantTripCount(TheLoop);
5157 if (TC > 1 && TC < TinyTripCountInterleaveThreshold)
5158 return 1;
5159
5160 unsigned TargetNumRegisters = TTI.getNumberOfRegisters(VF > 1);
5161 LLVM_DEBUG(dbgs() << "LV: The target has " << TargetNumRegistersdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The target has " <<
TargetNumRegisters << " registers\n"; } } while (false
)
5162 << " registers\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The target has " <<
TargetNumRegisters << " registers\n"; } } while (false
)
;
5163
5164 if (VF == 1) {
5165 if (ForceTargetNumScalarRegs.getNumOccurrences() > 0)
5166 TargetNumRegisters = ForceTargetNumScalarRegs;
5167 } else {
5168 if (ForceTargetNumVectorRegs.getNumOccurrences() > 0)
5169 TargetNumRegisters = ForceTargetNumVectorRegs;
5170 }
5171
5172 RegisterUsage R = calculateRegisterUsage({VF})[0];
5173 // We divide by these constants so assume that we have at least one
5174 // instruction that uses at least one register.
5175 R.MaxLocalUsers = std::max(R.MaxLocalUsers, 1U);
5176
5177 // We calculate the interleave count using the following formula.
5178 // Subtract the number of loop invariants from the number of available
5179 // registers. These registers are used by all of the interleaved instances.
5180 // Next, divide the remaining registers by the number of registers that is
5181 // required by the loop, in order to estimate how many parallel instances
5182 // fit without causing spills. All of this is rounded down if necessary to be
5183 // a power of two. We want power of two interleave count to simplify any
5184 // addressing operations or alignment considerations.
5185 unsigned IC = PowerOf2Floor((TargetNumRegisters - R.LoopInvariantRegs) /
5186 R.MaxLocalUsers);
5187
5188 // Don't count the induction variable as interleaved.
5189 if (EnableIndVarRegisterHeur)
5190 IC = PowerOf2Floor((TargetNumRegisters - R.LoopInvariantRegs - 1) /
5191 std::max(1U, (R.MaxLocalUsers - 1)));
5192
5193 // Clamp the interleave ranges to reasonable counts.
5194 unsigned MaxInterleaveCount = TTI.getMaxInterleaveFactor(VF);
5195
5196 // Check if the user has overridden the max.
5197 if (VF == 1) {
5198 if (ForceTargetMaxScalarInterleaveFactor.getNumOccurrences() > 0)
5199 MaxInterleaveCount = ForceTargetMaxScalarInterleaveFactor;
5200 } else {
5201 if (ForceTargetMaxVectorInterleaveFactor.getNumOccurrences() > 0)
5202 MaxInterleaveCount = ForceTargetMaxVectorInterleaveFactor;
5203 }
5204
5205 // If we did not calculate the cost for VF (because the user selected the VF)
5206 // then we calculate the cost of VF here.
5207 if (LoopCost == 0)
5208 LoopCost = expectedCost(VF).first;
5209
5210 // Clamp the calculated IC to be between the 1 and the max interleave count
5211 // that the target allows.
5212 if (IC > MaxInterleaveCount)
5213 IC = MaxInterleaveCount;
5214 else if (IC < 1)
5215 IC = 1;
5216
5217 // Interleave if we vectorized this loop and there is a reduction that could
5218 // benefit from interleaving.
5219 if (VF > 1 && !Legal->getReductionVars()->empty()) {
5220 LLVM_DEBUG(dbgs() << "LV: Interleaving because of reductions.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving because of reductions.\n"
; } } while (false)
;
5221 return IC;
5222 }
5223
5224 // Note that if we've already vectorized the loop we will have done the
5225 // runtime check and so interleaving won't require further checks.
5226 bool InterleavingRequiresRuntimePointerCheck =
5227 (VF == 1 && Legal->getRuntimePointerChecking()->Need);
5228
5229 // We want to interleave small loops in order to reduce the loop overhead and
5230 // potentially expose ILP opportunities.
5231 LLVM_DEBUG(dbgs() << "LV: Loop cost is " << LoopCost << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop cost is " <<
LoopCost << '\n'; } } while (false)
;
5232 if (!InterleavingRequiresRuntimePointerCheck && LoopCost < SmallLoopCost) {
5233 // We assume that the cost overhead is 1 and we use the cost model
5234 // to estimate the cost of the loop and interleave until the cost of the
5235 // loop overhead is about 5% of the cost of the loop.
5236 unsigned SmallIC =
5237 std::min(IC, (unsigned)PowerOf2Floor(SmallLoopCost / LoopCost));
5238
5239 // Interleave until store/load ports (estimated by max interleave count) are
5240 // saturated.
5241 unsigned NumStores = Legal->getNumStores();
5242 unsigned NumLoads = Legal->getNumLoads();
5243 unsigned StoresIC = IC / (NumStores ? NumStores : 1);
5244 unsigned LoadsIC = IC / (NumLoads ? NumLoads : 1);
5245
5246 // If we have a scalar reduction (vector reductions are already dealt with
5247 // by this point), we can increase the critical path length if the loop
5248 // we're interleaving is inside another loop. Limit, by default to 2, so the
5249 // critical path only gets increased by one reduction operation.
5250 if (!Legal->getReductionVars()->empty() && TheLoop->getLoopDepth() > 1) {
5251 unsigned F = static_cast<unsigned>(MaxNestedScalarReductionIC);
5252 SmallIC = std::min(SmallIC, F);
5253 StoresIC = std::min(StoresIC, F);
5254 LoadsIC = std::min(LoadsIC, F);
5255 }
5256
5257 if (EnableLoadStoreRuntimeInterleave &&
5258 std::max(StoresIC, LoadsIC) > SmallIC) {
5259 LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving to saturate store or load ports.\n"
; } } while (false)
5260 dbgs() << "LV: Interleaving to saturate store or load ports.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving to saturate store or load ports.\n"
; } } while (false)
;
5261 return std::max(StoresIC, LoadsIC);
5262 }
5263
5264 LLVM_DEBUG(dbgs() << "LV: Interleaving to reduce branch cost.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving to reduce branch cost.\n"
; } } while (false)
;
5265 return SmallIC;
5266 }
5267
5268 // Interleave if this is a large loop (small loops are already dealt with by
5269 // this point) that could benefit from interleaving.
5270 bool HasReductions = !Legal->getReductionVars()->empty();
5271 if (TTI.enableAggressiveInterleaving(HasReductions)) {
5272 LLVM_DEBUG(dbgs() << "LV: Interleaving to expose ILP.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving to expose ILP.\n"
; } } while (false)
;
5273 return IC;
5274 }
5275
5276 LLVM_DEBUG(dbgs() << "LV: Not Interleaving.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not Interleaving.\n"
; } } while (false)
;
5277 return 1;
5278}
5279
5280SmallVector<LoopVectorizationCostModel::RegisterUsage, 8>
5281LoopVectorizationCostModel::calculateRegisterUsage(ArrayRef<unsigned> VFs) {
5282 // This function calculates the register usage by measuring the highest number
5283 // of values that are alive at a single location. Obviously, this is a very
5284 // rough estimation. We scan the loop in a topological order in order and
5285 // assign a number to each instruction. We use RPO to ensure that defs are
5286 // met before their users. We assume that each instruction that has in-loop
5287 // users starts an interval. We record every time that an in-loop value is
5288 // used, so we have a list of the first and last occurrences of each
5289 // instruction. Next, we transpose this data structure into a multi map that
5290 // holds the list of intervals that *end* at a specific location. This multi
5291 // map allows us to perform a linear search. We scan the instructions linearly
5292 // and record each time that a new interval starts, by placing it in a set.
5293 // If we find this value in the multi-map then we remove it from the set.
5294 // The max register usage is the maximum size of the set.
5295 // We also search for instructions that are defined outside the loop, but are
5296 // used inside the loop. We need this number separately from the max-interval
5297 // usage number because when we unroll, loop-invariant values do not take
5298 // more register.
5299 LoopBlocksDFS DFS(TheLoop);
5300 DFS.perform(LI);
5301
5302 RegisterUsage RU;
5303
5304 // Each 'key' in the map opens a new interval. The values
5305 // of the map are the index of the 'last seen' usage of the
5306 // instruction that is the key.
5307 using IntervalMap = DenseMap<Instruction *, unsigned>;
5308
5309 // Maps instruction to its index.
5310 DenseMap<unsigned, Instruction *> IdxToInstr;
5311 // Marks the end of each interval.
5312 IntervalMap EndPoint;
5313 // Saves the list of instruction indices that are used in the loop.
5314 SmallPtrSet<Instruction *, 8> Ends;
5315 // Saves the list of values that are used in the loop but are
5316 // defined outside the loop, such as arguments and constants.
5317 SmallPtrSet<Value *, 8> LoopInvariants;
5318
5319 unsigned Index = 0;
5320 for (BasicBlock *BB : make_range(DFS.beginRPO(), DFS.endRPO())) {
5321 for (Instruction &I : *BB) {
5322 IdxToInstr[Index++] = &I;
5323
5324 // Save the end location of each USE.
5325 for (Value *U : I.operands()) {
5326 auto *Instr = dyn_cast<Instruction>(U);
5327
5328 // Ignore non-instruction values such as arguments, constants, etc.
5329 if (!Instr)
5330 continue;
5331
5332 // If this instruction is outside the loop then record it and continue.
5333 if (!TheLoop->contains(Instr)) {
5334 LoopInvariants.insert(Instr);
5335 continue;
5336 }
5337
5338 // Overwrite previous end points.
5339 EndPoint[Instr] = Index;
5340 Ends.insert(Instr);
5341 }
5342 }
5343 }
5344
5345 // Saves the list of intervals that end with the index in 'key'.
5346 using InstrList = SmallVector<Instruction *, 2>;
5347 DenseMap<unsigned, InstrList> TransposeEnds;
5348
5349 // Transpose the EndPoints to a list of values that end at each index.
5350 for (auto &Interval : EndPoint)
5351 TransposeEnds[Interval.second].push_back(Interval.first);
5352
5353 SmallPtrSet<Instruction *, 8> OpenIntervals;
5354
5355 // Get the size of the widest register.
5356 unsigned MaxSafeDepDist = -1U;
5357 if (Legal->getMaxSafeDepDistBytes() != -1U)
5358 MaxSafeDepDist = Legal->getMaxSafeDepDistBytes() * 8;
5359 unsigned WidestRegister =
5360 std::min(TTI.getRegisterBitWidth(true), MaxSafeDepDist);
5361 const DataLayout &DL = TheFunction->getParent()->getDataLayout();
5362
5363 SmallVector<RegisterUsage, 8> RUs(VFs.size());
5364 SmallVector<unsigned, 8> MaxUsages(VFs.size(), 0);
5365
5366 LLVM_DEBUG(dbgs() << "LV(REG): Calculating max register usage:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): Calculating max register usage:\n"
; } } while (false)
;
5367
5368 // A lambda that gets the register usage for the given type and VF.
5369 auto GetRegUsage = [&DL, WidestRegister](Type *Ty, unsigned VF) {
5370 if (Ty->isTokenTy())
5371 return 0U;
5372 unsigned TypeSize = DL.getTypeSizeInBits(Ty->getScalarType());
5373 return std::max<unsigned>(1, VF * TypeSize / WidestRegister);
5374 };
5375
5376 for (unsigned int i = 0; i < Index; ++i) {
5377 Instruction *I = IdxToInstr[i];
5378
5379 // Remove all of the instructions that end at this location.
5380 InstrList &List = TransposeEnds[i];
5381 for (Instruction *ToRemove : List)
5382 OpenIntervals.erase(ToRemove);
5383
5384 // Ignore instructions that are never used within the loop.
5385 if (!Ends.count(I))
5386 continue;
5387
5388 // Skip ignored values.
5389 if (ValuesToIgnore.count(I))
5390 continue;
5391
5392 // For each VF find the maximum usage of registers.
5393 for (unsigned j = 0, e = VFs.size(); j < e; ++j) {
5394 if (VFs[j] == 1) {
5395 MaxUsages[j] = std::max(MaxUsages[j], OpenIntervals.size());
5396 continue;
5397 }
5398 collectUniformsAndScalars(VFs[j]);
5399 // Count the number of live intervals.
5400 unsigned RegUsage = 0;
5401 for (auto Inst : OpenIntervals) {
5402 // Skip ignored values for VF > 1.
5403 if (VecValuesToIgnore.count(Inst) ||
5404 isScalarAfterVectorization(Inst, VFs[j]))
5405 continue;
5406 RegUsage += GetRegUsage(Inst->getType(), VFs[j]);
5407 }
5408 MaxUsages[j] = std::max(MaxUsages[j], RegUsage);
5409 }
5410
5411 LLVM_DEBUG(dbgs() << "LV(REG): At #" << i << " Interval # "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): At #" <<
i << " Interval # " << OpenIntervals.size() <<
'\n'; } } while (false)
5412 << OpenIntervals.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): At #" <<
i << " Interval # " << OpenIntervals.size() <<
'\n'; } } while (false)
;
5413
5414 // Add the current instruction to the list of open intervals.
5415 OpenIntervals.insert(I);
5416 }
5417
5418 for (unsigned i = 0, e = VFs.size(); i < e; ++i) {
5419 unsigned Invariant = 0;
5420 if (VFs[i] == 1)
5421 Invariant = LoopInvariants.size();
5422 else {
5423 for (auto Inst : LoopInvariants)
5424 Invariant += GetRegUsage(Inst->getType(), VFs[i]);
5425 }
5426
5427 LLVM_DEBUG(dbgs() << "LV(REG): VF = " << VFs[i] << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): VF = " <<
VFs[i] << '\n'; } } while (false)
;
5428 LLVM_DEBUG(dbgs() << "LV(REG): Found max usage: " << MaxUsages[i] << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): Found max usage: "
<< MaxUsages[i] << '\n'; } } while (false)
;
5429 LLVM_DEBUG(dbgs() << "LV(REG): Found invariant usage: " << Invariantdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): Found invariant usage: "
<< Invariant << '\n'; } } while (false)
5430 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): Found invariant usage: "
<< Invariant << '\n'; } } while (false)
;
5431
5432 RU.LoopInvariantRegs = Invariant;
5433 RU.MaxLocalUsers = MaxUsages[i];
5434 RUs[i] = RU;
5435 }
5436
5437 return RUs;
5438}
5439
5440bool LoopVectorizationCostModel::useEmulatedMaskMemRefHack(Instruction *I){
5441 // TODO: Cost model for emulated masked load/store is completely
5442 // broken. This hack guides the cost model to use an artificially
5443 // high enough value to practically disable vectorization with such
5444 // operations, except where previously deployed legality hack allowed
5445 // using very low cost values. This is to avoid regressions coming simply
5446 // from moving "masked load/store" check from legality to cost model.
5447 // Masked Load/Gather emulation was previously never allowed.
5448 // Limited number of Masked Store/Scatter emulation was allowed.
5449 assert(isScalarWithPredication(I) &&(static_cast <bool> (isScalarWithPredication(I) &&
"Expecting a scalar emulated instruction") ? void (0) : __assert_fail
("isScalarWithPredication(I) && \"Expecting a scalar emulated instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5450, __extension__ __PRETTY_FUNCTION__))
5450 "Expecting a scalar emulated instruction")(static_cast <bool> (isScalarWithPredication(I) &&
"Expecting a scalar emulated instruction") ? void (0) : __assert_fail
("isScalarWithPredication(I) && \"Expecting a scalar emulated instruction\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5450, __extension__ __PRETTY_FUNCTION__))
;
5451 return isa<LoadInst>(I) ||
5452 (isa<StoreInst>(I) &&
5453 NumPredStores > NumberOfStoresToPredicate);
5454}
5455
5456void LoopVectorizationCostModel::collectInstsToScalarize(unsigned VF) {
5457 // If we aren't vectorizing the loop, or if we've already collected the
5458 // instructions to scalarize, there's nothing to do. Collection may already
5459 // have occurred if we have a user-selected VF and are now computing the
5460 // expected cost for interleaving.
5461 if (VF < 2 || InstsToScalarize.count(VF))
5462 return;
5463
5464 // Initialize a mapping for VF in InstsToScalalarize. If we find that it's
5465 // not profitable to scalarize any instructions, the presence of VF in the
5466 // map will indicate that we've analyzed it already.
5467 ScalarCostsTy &ScalarCostsVF = InstsToScalarize[VF];
5468
5469 // Find all the instructions that are scalar with predication in the loop and
5470 // determine if it would be better to not if-convert the blocks they are in.
5471 // If so, we also record the instructions to scalarize.
5472 for (BasicBlock *BB : TheLoop->blocks()) {
5473 if (!Legal->blockNeedsPredication(BB))
5474 continue;
5475 for (Instruction &I : *BB)
5476 if (isScalarWithPredication(&I)) {
5477 ScalarCostsTy ScalarCosts;
5478 // Do not apply discount logic if hacked cost is needed
5479 // for emulated masked memrefs.
5480 if (!useEmulatedMaskMemRefHack(&I) &&
5481 computePredInstDiscount(&I, ScalarCosts, VF) >= 0)
5482 ScalarCostsVF.insert(ScalarCosts.begin(), ScalarCosts.end());
5483 // Remember that BB will remain after vectorization.
5484 PredicatedBBsAfterVectorization.insert(BB);
5485 }
5486 }
5487}
5488
5489int LoopVectorizationCostModel::computePredInstDiscount(
5490 Instruction *PredInst, DenseMap<Instruction *, unsigned> &ScalarCosts,
5491 unsigned VF) {
5492 assert(!isUniformAfterVectorization(PredInst, VF) &&(static_cast <bool> (!isUniformAfterVectorization(PredInst
, VF) && "Instruction marked uniform-after-vectorization will be predicated"
) ? void (0) : __assert_fail ("!isUniformAfterVectorization(PredInst, VF) && \"Instruction marked uniform-after-vectorization will be predicated\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5493, __extension__ __PRETTY_FUNCTION__))
5493 "Instruction marked uniform-after-vectorization will be predicated")(static_cast <bool> (!isUniformAfterVectorization(PredInst
, VF) && "Instruction marked uniform-after-vectorization will be predicated"
) ? void (0) : __assert_fail ("!isUniformAfterVectorization(PredInst, VF) && \"Instruction marked uniform-after-vectorization will be predicated\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5493, __extension__ __PRETTY_FUNCTION__))
;
5494
5495 // Initialize the discount to zero, meaning that the scalar version and the
5496 // vector version cost the same.
5497 int Discount = 0;
5498
5499 // Holds instructions to analyze. The instructions we visit are mapped in
5500 // ScalarCosts. Those instructions are the ones that would be scalarized if
5501 // we find that the scalar version costs less.
5502 SmallVector<Instruction *, 8> Worklist;
5503
5504 // Returns true if the given instruction can be scalarized.
5505 auto canBeScalarized = [&](Instruction *I) -> bool {
5506 // We only attempt to scalarize instructions forming a single-use chain
5507 // from the original predicated block that would otherwise be vectorized.
5508 // Although not strictly necessary, we give up on instructions we know will
5509 // already be scalar to avoid traversing chains that are unlikely to be