Bug Summary

File:lib/Transforms/Vectorize/LoopVectorize.cpp
Warning:line 5964, 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~svn324650/build-llvm/lib/Transforms/Vectorize -I /build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize -I /build/llvm-toolchain-snapshot-7~svn324650/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn324650/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0/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/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-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-7~svn324650/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-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-02-09-212803-22585-1 -x c++ /build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp
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//===----------------------------------------------------------------------===//
30//
31// The reduction-variable vectorization is based on the paper:
32// D. Nuzman and R. Henderson. Multi-platform Auto-vectorization.
33//
34// Variable uniformity checks are inspired by:
35// Karrenberg, R. and Hack, S. Whole Function Vectorization.
36//
37// The interleaved access vectorization is based on the paper:
38// Dorit Nuzman, Ira Rosen and Ayal Zaks. Auto-Vectorization of Interleaved
39// Data for SIMD
40//
41// Other ideas/concepts are from:
42// A. Zaks and D. Nuzman. Autovectorization in GCC-two years later.
43//
44// S. Maleki, Y. Gao, M. Garzaran, T. Wong and D. Padua. An Evaluation of
45// Vectorizing Compilers.
46//
47//===----------------------------------------------------------------------===//
48
49#include "llvm/Transforms/Vectorize/LoopVectorize.h"
50#include "LoopVectorizationPlanner.h"
51#include "llvm/ADT/APInt.h"
52#include "llvm/ADT/ArrayRef.h"
53#include "llvm/ADT/DenseMap.h"
54#include "llvm/ADT/DenseMapInfo.h"
55#include "llvm/ADT/Hashing.h"
56#include "llvm/ADT/MapVector.h"
57#include "llvm/ADT/None.h"
58#include "llvm/ADT/Optional.h"
59#include "llvm/ADT/SCCIterator.h"
60#include "llvm/ADT/STLExtras.h"
61#include "llvm/ADT/SetVector.h"
62#include "llvm/ADT/SmallPtrSet.h"
63#include "llvm/ADT/SmallSet.h"
64#include "llvm/ADT/SmallVector.h"
65#include "llvm/ADT/Statistic.h"
66#include "llvm/ADT/StringRef.h"
67#include "llvm/ADT/Twine.h"
68#include "llvm/ADT/iterator_range.h"
69#include "llvm/Analysis/AssumptionCache.h"
70#include "llvm/Analysis/BasicAliasAnalysis.h"
71#include "llvm/Analysis/BlockFrequencyInfo.h"
72#include "llvm/Analysis/CodeMetrics.h"
73#include "llvm/Analysis/DemandedBits.h"
74#include "llvm/Analysis/GlobalsModRef.h"
75#include "llvm/Analysis/LoopAccessAnalysis.h"
76#include "llvm/Analysis/LoopAnalysisManager.h"
77#include "llvm/Analysis/LoopInfo.h"
78#include "llvm/Analysis/LoopIterator.h"
79#include "llvm/Analysis/OptimizationRemarkEmitter.h"
80#include "llvm/Analysis/ScalarEvolution.h"
81#include "llvm/Analysis/ScalarEvolutionExpander.h"
82#include "llvm/Analysis/ScalarEvolutionExpressions.h"
83#include "llvm/Analysis/TargetLibraryInfo.h"
84#include "llvm/Analysis/TargetTransformInfo.h"
85#include "llvm/Analysis/VectorUtils.h"
86#include "llvm/IR/Attributes.h"
87#include "llvm/IR/BasicBlock.h"
88#include "llvm/IR/CFG.h"
89#include "llvm/IR/Constant.h"
90#include "llvm/IR/Constants.h"
91#include "llvm/IR/DataLayout.h"
92#include "llvm/IR/DebugInfoMetadata.h"
93#include "llvm/IR/DebugLoc.h"
94#include "llvm/IR/DerivedTypes.h"
95#include "llvm/IR/DiagnosticInfo.h"
96#include "llvm/IR/Dominators.h"
97#include "llvm/IR/Function.h"
98#include "llvm/IR/IRBuilder.h"
99#include "llvm/IR/InstrTypes.h"
100#include "llvm/IR/Instruction.h"
101#include "llvm/IR/Instructions.h"
102#include "llvm/IR/IntrinsicInst.h"
103#include "llvm/IR/Intrinsics.h"
104#include "llvm/IR/LLVMContext.h"
105#include "llvm/IR/Metadata.h"
106#include "llvm/IR/Module.h"
107#include "llvm/IR/Operator.h"
108#include "llvm/IR/Type.h"
109#include "llvm/IR/Use.h"
110#include "llvm/IR/User.h"
111#include "llvm/IR/Value.h"
112#include "llvm/IR/ValueHandle.h"
113#include "llvm/IR/Verifier.h"
114#include "llvm/Pass.h"
115#include "llvm/Support/Casting.h"
116#include "llvm/Support/CommandLine.h"
117#include "llvm/Support/Compiler.h"
118#include "llvm/Support/Debug.h"
119#include "llvm/Support/ErrorHandling.h"
120#include "llvm/Support/MathExtras.h"
121#include "llvm/Support/raw_ostream.h"
122#include "llvm/Transforms/Utils/BasicBlockUtils.h"
123#include "llvm/Transforms/Utils/LoopSimplify.h"
124#include "llvm/Transforms/Utils/LoopUtils.h"
125#include "llvm/Transforms/Utils/LoopVersioning.h"
126#include <algorithm>
127#include <cassert>
128#include <cstdint>
129#include <cstdlib>
130#include <functional>
131#include <iterator>
132#include <limits>
133#include <memory>
134#include <string>
135#include <tuple>
136#include <utility>
137#include <vector>
138
139using namespace llvm;
140
141#define LV_NAME"loop-vectorize" "loop-vectorize"
142#define DEBUG_TYPE"loop-vectorize" LV_NAME"loop-vectorize"
143
144STATISTIC(LoopsVectorized, "Number of loops vectorized")static llvm::Statistic LoopsVectorized = {"loop-vectorize", "LoopsVectorized"
, "Number of loops vectorized", {0}, {false}}
;
145STATISTIC(LoopsAnalyzed, "Number of loops analyzed for vectorization")static llvm::Statistic LoopsAnalyzed = {"loop-vectorize", "LoopsAnalyzed"
, "Number of loops analyzed for vectorization", {0}, {false}}
;
146
147static cl::opt<bool>
148 EnableIfConversion("enable-if-conversion", cl::init(true), cl::Hidden,
149 cl::desc("Enable if-conversion during vectorization."));
150
151/// Loops with a known constant trip count below this number are vectorized only
152/// if no scalar iteration overheads are incurred.
153static cl::opt<unsigned> TinyTripCountVectorThreshold(
154 "vectorizer-min-trip-count", cl::init(16), cl::Hidden,
155 cl::desc("Loops with a constant trip count that is smaller than this "
156 "value are vectorized only if no scalar iteration overheads "
157 "are incurred."));
158
159static cl::opt<bool> MaximizeBandwidth(
160 "vectorizer-maximize-bandwidth", cl::init(false), cl::Hidden,
161 cl::desc("Maximize bandwidth when selecting vectorization factor which "
162 "will be determined by the smallest type in loop."));
163
164static cl::opt<bool> EnableInterleavedMemAccesses(
165 "enable-interleaved-mem-accesses", cl::init(false), cl::Hidden,
166 cl::desc("Enable vectorization on interleaved memory accesses in a loop"));
167
168/// Maximum factor for an interleaved memory access.
169static cl::opt<unsigned> MaxInterleaveGroupFactor(
170 "max-interleave-group-factor", cl::Hidden,
171 cl::desc("Maximum factor for an interleaved access group (default = 8)"),
172 cl::init(8));
173
174/// We don't interleave loops with a known constant trip count below this
175/// number.
176static const unsigned TinyTripCountInterleaveThreshold = 128;
177
178static cl::opt<unsigned> ForceTargetNumScalarRegs(
179 "force-target-num-scalar-regs", cl::init(0), cl::Hidden,
180 cl::desc("A flag that overrides the target's number of scalar registers."));
181
182static cl::opt<unsigned> ForceTargetNumVectorRegs(
183 "force-target-num-vector-regs", cl::init(0), cl::Hidden,
184 cl::desc("A flag that overrides the target's number of vector registers."));
185
186/// Maximum vectorization interleave count.
187static const unsigned MaxInterleaveFactor = 16;
188
189static cl::opt<unsigned> ForceTargetMaxScalarInterleaveFactor(
190 "force-target-max-scalar-interleave", cl::init(0), cl::Hidden,
191 cl::desc("A flag that overrides the target's max interleave factor for "
192 "scalar loops."));
193
194static cl::opt<unsigned> ForceTargetMaxVectorInterleaveFactor(
195 "force-target-max-vector-interleave", cl::init(0), cl::Hidden,
196 cl::desc("A flag that overrides the target's max interleave factor for "
197 "vectorized loops."));
198
199static cl::opt<unsigned> ForceTargetInstructionCost(
200 "force-target-instruction-cost", cl::init(0), cl::Hidden,
201 cl::desc("A flag that overrides the target's expected cost for "
202 "an instruction to a single constant value. Mostly "
203 "useful for getting consistent testing."));
204
205static cl::opt<unsigned> SmallLoopCost(
206 "small-loop-cost", cl::init(20), cl::Hidden,
207 cl::desc(
208 "The cost of a loop that is considered 'small' by the interleaver."));
209
210static cl::opt<bool> LoopVectorizeWithBlockFrequency(
211 "loop-vectorize-with-block-frequency", cl::init(true), cl::Hidden,
212 cl::desc("Enable the use of the block frequency analysis to access PGO "
213 "heuristics minimizing code growth in cold regions and being more "
214 "aggressive in hot regions."));
215
216// Runtime interleave loops for load/store throughput.
217static cl::opt<bool> EnableLoadStoreRuntimeInterleave(
218 "enable-loadstore-runtime-interleave", cl::init(true), cl::Hidden,
219 cl::desc(
220 "Enable runtime interleaving until load/store ports are saturated"));
221
222/// The number of stores in a loop that are allowed to need predication.
223static cl::opt<unsigned> NumberOfStoresToPredicate(
224 "vectorize-num-stores-pred", cl::init(1), cl::Hidden,
225 cl::desc("Max number of stores to be predicated behind an if."));
226
227static cl::opt<bool> EnableIndVarRegisterHeur(
228 "enable-ind-var-reg-heur", cl::init(true), cl::Hidden,
229 cl::desc("Count the induction variable only once when interleaving"));
230
231static cl::opt<bool> EnableCondStoresVectorization(
232 "enable-cond-stores-vec", cl::init(true), cl::Hidden,
233 cl::desc("Enable if predication of stores during vectorization."));
234
235static cl::opt<unsigned> MaxNestedScalarReductionIC(
236 "max-nested-scalar-reduction-interleave", cl::init(2), cl::Hidden,
237 cl::desc("The maximum interleave count to use when interleaving a scalar "
238 "reduction in a nested loop."));
239
240static cl::opt<unsigned> PragmaVectorizeMemoryCheckThreshold(
241 "pragma-vectorize-memory-check-threshold", cl::init(128), cl::Hidden,
242 cl::desc("The maximum allowed number of runtime memory checks with a "
243 "vectorize(enable) pragma."));
244
245static cl::opt<unsigned> VectorizeSCEVCheckThreshold(
246 "vectorize-scev-check-threshold", cl::init(16), cl::Hidden,
247 cl::desc("The maximum number of SCEV checks allowed."));
248
249static cl::opt<unsigned> PragmaVectorizeSCEVCheckThreshold(
250 "pragma-vectorize-scev-check-threshold", cl::init(128), cl::Hidden,
251 cl::desc("The maximum number of SCEV checks allowed with a "
252 "vectorize(enable) pragma"));
253
254/// Create an analysis remark that explains why vectorization failed
255///
256/// \p PassName is the name of the pass (e.g. can be AlwaysPrint). \p
257/// RemarkName is the identifier for the remark. If \p I is passed it is an
258/// instruction that prevents vectorization. Otherwise \p TheLoop is used for
259/// the location of the remark. \return the remark object that can be
260/// streamed to.
261static OptimizationRemarkAnalysis
262createMissedAnalysis(const char *PassName, StringRef RemarkName, Loop *TheLoop,
263 Instruction *I = nullptr) {
264 Value *CodeRegion = TheLoop->getHeader();
265 DebugLoc DL = TheLoop->getStartLoc();
266
267 if (I) {
268 CodeRegion = I->getParent();
269 // If there is no debug location attached to the instruction, revert back to
270 // using the loop's.
271 if (I->getDebugLoc())
272 DL = I->getDebugLoc();
273 }
274
275 OptimizationRemarkAnalysis R(PassName, RemarkName, DL, CodeRegion);
276 R << "loop not vectorized: ";
277 return R;
278}
279
280namespace {
281
282class LoopVectorizationRequirements;
283
284} // end anonymous namespace
285
286/// Returns true if the given loop body has a cycle, excluding the loop
287/// itself.
288static bool hasCyclesInLoopBody(const Loop &L) {
289 if (!L.empty())
290 return true;
291
292 for (const auto &SCC :
293 make_range(scc_iterator<Loop, LoopBodyTraits>::begin(L),
294 scc_iterator<Loop, LoopBodyTraits>::end(L))) {
295 if (SCC.size() > 1) {
296 DEBUG(dbgs() << "LVL: Detected a cycle in the loop body:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LVL: Detected a cycle in the loop body:\n"
; } } while (false)
;
297 DEBUG(L.dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { L.dump(); } } while (false)
;
298 return true;
299 }
300 }
301 return false;
302}
303
304/// A helper function for converting Scalar types to vector types.
305/// If the incoming type is void, we return void. If the VF is 1, we return
306/// the scalar type.
307static Type *ToVectorTy(Type *Scalar, unsigned VF) {
308 if (Scalar->isVoidTy() || VF == 1)
309 return Scalar;
310 return VectorType::get(Scalar, VF);
311}
312
313// FIXME: The following helper functions have multiple implementations
314// in the project. They can be effectively organized in a common Load/Store
315// utilities unit.
316
317/// A helper function that returns the pointer operand of a load or store
318/// instruction.
319static Value *getPointerOperand(Value *I) {
320 if (auto *LI = dyn_cast<LoadInst>(I))
321 return LI->getPointerOperand();
322 if (auto *SI = dyn_cast<StoreInst>(I))
323 return SI->getPointerOperand();
324 return nullptr;
325}
326
327/// A helper function that returns the type of loaded or stored value.
328static Type *getMemInstValueType(Value *I) {
329 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 330, __extension__ __PRETTY_FUNCTION__))
330 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 330, __extension__ __PRETTY_FUNCTION__))
;
331 if (auto *LI = dyn_cast<LoadInst>(I))
332 return LI->getType();
333 return cast<StoreInst>(I)->getValueOperand()->getType();
334}
335
336/// A helper function that returns the alignment of load or store instruction.
337static unsigned getMemInstAlignment(Value *I) {
338 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 339, __extension__ __PRETTY_FUNCTION__))
339 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 339, __extension__ __PRETTY_FUNCTION__))
;
340 if (auto *LI = dyn_cast<LoadInst>(I))
341 return LI->getAlignment();
342 return cast<StoreInst>(I)->getAlignment();
343}
344
345/// A helper function that returns the address space of the pointer operand of
346/// load or store instruction.
347static unsigned getMemInstAddressSpace(Value *I) {
348 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 349, __extension__ __PRETTY_FUNCTION__))
349 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 349, __extension__ __PRETTY_FUNCTION__))
;
350 if (auto *LI = dyn_cast<LoadInst>(I))
351 return LI->getPointerAddressSpace();
352 return cast<StoreInst>(I)->getPointerAddressSpace();
353}
354
355/// A helper function that returns true if the given type is irregular. The
356/// type is irregular if its allocated size doesn't equal the store size of an
357/// element of the corresponding vector type at the given vectorization factor.
358static bool hasIrregularType(Type *Ty, const DataLayout &DL, unsigned VF) {
359 // Determine if an array of VF elements of type Ty is "bitcast compatible"
360 // with a <VF x Ty> vector.
361 if (VF > 1) {
362 auto *VectorTy = VectorType::get(Ty, VF);
363 return VF * DL.getTypeAllocSize(Ty) != DL.getTypeStoreSize(VectorTy);
364 }
365
366 // If the vectorization factor is one, we just check if an array of type Ty
367 // requires padding between elements.
368 return DL.getTypeAllocSizeInBits(Ty) != DL.getTypeSizeInBits(Ty);
369}
370
371/// A helper function that returns the reciprocal of the block probability of
372/// predicated blocks. If we return X, we are assuming the predicated block
373/// will execute once for every X iterations of the loop header.
374///
375/// TODO: We should use actual block probability here, if available. Currently,
376/// we always assume predicated blocks have a 50% chance of executing.
377static unsigned getReciprocalPredBlockProb() { return 2; }
378
379/// A helper function that adds a 'fast' flag to floating-point operations.
380static Value *addFastMathFlag(Value *V) {
381 if (isa<FPMathOperator>(V)) {
382 FastMathFlags Flags;
383 Flags.setFast();
384 cast<Instruction>(V)->setFastMathFlags(Flags);
385 }
386 return V;
387}
388
389/// A helper function that returns an integer or floating-point constant with
390/// value C.
391static Constant *getSignedIntOrFpConstant(Type *Ty, int64_t C) {
392 return Ty->isIntegerTy() ? ConstantInt::getSigned(Ty, C)
393 : ConstantFP::get(Ty, C);
394}
395
396namespace llvm {
397
398/// InnerLoopVectorizer vectorizes loops which contain only one basic
399/// block to a specified vectorization factor (VF).
400/// This class performs the widening of scalars into vectors, or multiple
401/// scalars. This class also implements the following features:
402/// * It inserts an epilogue loop for handling loops that don't have iteration
403/// counts that are known to be a multiple of the vectorization factor.
404/// * It handles the code generation for reduction variables.
405/// * Scalarization (implementation using scalars) of un-vectorizable
406/// instructions.
407/// InnerLoopVectorizer does not perform any vectorization-legality
408/// checks, and relies on the caller to check for the different legality
409/// aspects. The InnerLoopVectorizer relies on the
410/// LoopVectorizationLegality class to provide information about the induction
411/// and reduction variables that were found to a given vectorization factor.
412class InnerLoopVectorizer {
413public:
414 InnerLoopVectorizer(Loop *OrigLoop, PredicatedScalarEvolution &PSE,
415 LoopInfo *LI, DominatorTree *DT,
416 const TargetLibraryInfo *TLI,
417 const TargetTransformInfo *TTI, AssumptionCache *AC,
418 OptimizationRemarkEmitter *ORE, unsigned VecWidth,
419 unsigned UnrollFactor, LoopVectorizationLegality *LVL,
420 LoopVectorizationCostModel *CM)
421 : OrigLoop(OrigLoop), PSE(PSE), LI(LI), DT(DT), TLI(TLI), TTI(TTI),
422 AC(AC), ORE(ORE), VF(VecWidth), UF(UnrollFactor),
423 Builder(PSE.getSE()->getContext()),
424 VectorLoopValueMap(UnrollFactor, VecWidth), Legal(LVL), Cost(CM) {}
425 virtual ~InnerLoopVectorizer() = default;
426
427 /// Create a new empty loop. Unlink the old loop and connect the new one.
428 /// Return the pre-header block of the new loop.
429 BasicBlock *createVectorizedLoopSkeleton();
430
431 /// Widen a single instruction within the innermost loop.
432 void widenInstruction(Instruction &I);
433
434 /// Fix the vectorized code, taking care of header phi's, live-outs, and more.
435 void fixVectorizedLoop();
436
437 // Return true if any runtime check is added.
438 bool areSafetyChecksAdded() { return AddedSafetyChecks; }
439
440 /// A type for vectorized values in the new loop. Each value from the
441 /// original loop, when vectorized, is represented by UF vector values in the
442 /// new unrolled loop, where UF is the unroll factor.
443 using VectorParts = SmallVector<Value *, 2>;
444
445 /// Vectorize a single PHINode in a block. This method handles the induction
446 /// variable canonicalization. It supports both VF = 1 for unrolled loops and
447 /// arbitrary length vectors.
448 void widenPHIInstruction(Instruction *PN, unsigned UF, unsigned VF);
449
450 /// A helper function to scalarize a single Instruction in the innermost loop.
451 /// Generates a sequence of scalar instances for each lane between \p MinLane
452 /// and \p MaxLane, times each part between \p MinPart and \p MaxPart,
453 /// inclusive..
454 void scalarizeInstruction(Instruction *Instr, const VPIteration &Instance,
455 bool IfPredicateInstr);
456
457 /// Widen an integer or floating-point induction variable \p IV. If \p Trunc
458 /// is provided, the integer induction variable will first be truncated to
459 /// the corresponding type.
460 void widenIntOrFpInduction(PHINode *IV, TruncInst *Trunc = nullptr);
461
462 /// getOrCreateVectorValue and getOrCreateScalarValue coordinate to generate a
463 /// vector or scalar value on-demand if one is not yet available. When
464 /// vectorizing a loop, we visit the definition of an instruction before its
465 /// uses. When visiting the definition, we either vectorize or scalarize the
466 /// instruction, creating an entry for it in the corresponding map. (In some
467 /// cases, such as induction variables, we will create both vector and scalar
468 /// entries.) Then, as we encounter uses of the definition, we derive values
469 /// for each scalar or vector use unless such a value is already available.
470 /// For example, if we scalarize a definition and one of its uses is vector,
471 /// we build the required vector on-demand with an insertelement sequence
472 /// when visiting the use. Otherwise, if the use is scalar, we can use the
473 /// existing scalar definition.
474 ///
475 /// Return a value in the new loop corresponding to \p V from the original
476 /// loop at unroll index \p Part. If the value has already been vectorized,
477 /// the corresponding vector entry in VectorLoopValueMap is returned. If,
478 /// however, the value has a scalar entry in VectorLoopValueMap, we construct
479 /// a new vector value on-demand by inserting the scalar values into a vector
480 /// with an insertelement sequence. If the value has been neither vectorized
481 /// nor scalarized, it must be loop invariant, so we simply broadcast the
482 /// value into a vector.
483 Value *getOrCreateVectorValue(Value *V, unsigned Part);
484
485 /// Return a value in the new loop corresponding to \p V from the original
486 /// loop at unroll and vector indices \p Instance. If the value has been
487 /// vectorized but not scalarized, the necessary extractelement instruction
488 /// will be generated.
489 Value *getOrCreateScalarValue(Value *V, const VPIteration &Instance);
490
491 /// Construct the vector value of a scalarized value \p V one lane at a time.
492 void packScalarIntoVectorValue(Value *V, const VPIteration &Instance);
493
494 /// Try to vectorize the interleaved access group that \p Instr belongs to.
495 void vectorizeInterleaveGroup(Instruction *Instr);
496
497 /// Vectorize Load and Store instructions, optionally masking the vector
498 /// operations if \p BlockInMask is non-null.
499 void vectorizeMemoryInstruction(Instruction *Instr,
500 VectorParts *BlockInMask = nullptr);
501
502 /// \brief Set the debug location in the builder using the debug location in
503 /// the instruction.
504 void setDebugLocFromInst(IRBuilder<> &B, const Value *Ptr);
505
506protected:
507 friend class LoopVectorizationPlanner;
508
509 /// A small list of PHINodes.
510 using PhiVector = SmallVector<PHINode *, 4>;
511
512 /// A type for scalarized values in the new loop. Each value from the
513 /// original loop, when scalarized, is represented by UF x VF scalar values
514 /// in the new unrolled loop, where UF is the unroll factor and VF is the
515 /// vectorization factor.
516 using ScalarParts = SmallVector<SmallVector<Value *, 4>, 2>;
517
518 /// Set up the values of the IVs correctly when exiting the vector loop.
519 void fixupIVUsers(PHINode *OrigPhi, const InductionDescriptor &II,
520 Value *CountRoundDown, Value *EndValue,
521 BasicBlock *MiddleBlock);
522
523 /// Create a new induction variable inside L.
524 PHINode *createInductionVariable(Loop *L, Value *Start, Value *End,
525 Value *Step, Instruction *DL);
526
527 /// Handle all cross-iteration phis in the header.
528 void fixCrossIterationPHIs();
529
530 /// Fix a first-order recurrence. This is the second phase of vectorizing
531 /// this phi node.
532 void fixFirstOrderRecurrence(PHINode *Phi);
533
534 /// Fix a reduction cross-iteration phi. This is the second phase of
535 /// vectorizing this phi node.
536 void fixReduction(PHINode *Phi);
537
538 /// \brief The Loop exit block may have single value PHI nodes with some
539 /// incoming value. While vectorizing we only handled real values
540 /// that were defined inside the loop and we should have one value for
541 /// each predecessor of its parent basic block. See PR14725.
542 void fixLCSSAPHIs();
543
544 /// Iteratively sink the scalarized operands of a predicated instruction into
545 /// the block that was created for it.
546 void sinkScalarOperands(Instruction *PredInst);
547
548 /// Shrinks vector element sizes to the smallest bitwidth they can be legally
549 /// represented as.
550 void truncateToMinimalBitwidths();
551
552 /// Insert the new loop to the loop hierarchy and pass manager
553 /// and update the analysis passes.
554 void updateAnalysis();
555
556 /// Create a broadcast instruction. This method generates a broadcast
557 /// instruction (shuffle) for loop invariant values and for the induction
558 /// value. If this is the induction variable then we extend it to N, N+1, ...
559 /// this is needed because each iteration in the loop corresponds to a SIMD
560 /// element.
561 virtual Value *getBroadcastInstrs(Value *V);
562
563 /// This function adds (StartIdx, StartIdx + Step, StartIdx + 2*Step, ...)
564 /// to each vector element of Val. The sequence starts at StartIndex.
565 /// \p Opcode is relevant for FP induction variable.
566 virtual Value *getStepVector(Value *Val, int StartIdx, Value *Step,
567 Instruction::BinaryOps Opcode =
568 Instruction::BinaryOpsEnd);
569
570 /// Compute scalar induction steps. \p ScalarIV is the scalar induction
571 /// variable on which to base the steps, \p Step is the size of the step, and
572 /// \p EntryVal is the value from the original loop that maps to the steps.
573 /// Note that \p EntryVal doesn't have to be an induction variable (e.g., it
574 /// can be a truncate instruction).
575 void buildScalarSteps(Value *ScalarIV, Value *Step, Value *EntryVal,
576 const InductionDescriptor &ID);
577
578 /// Create a vector induction phi node based on an existing scalar one. \p
579 /// EntryVal is the value from the original loop that maps to the vector phi
580 /// node, and \p Step is the loop-invariant step. If \p EntryVal is a
581 /// truncate instruction, instead of widening the original IV, we widen a
582 /// version of the IV truncated to \p EntryVal's type.
583 void createVectorIntOrFpInductionPHI(const InductionDescriptor &II,
584 Value *Step, Instruction *EntryVal);
585
586 /// Returns true if an instruction \p I should be scalarized instead of
587 /// vectorized for the chosen vectorization factor.
588 bool shouldScalarizeInstruction(Instruction *I) const;
589
590 /// Returns true if we should generate a scalar version of \p IV.
591 bool needsScalarInduction(Instruction *IV) const;
592
593 /// If there is a cast involved in the induction variable \p ID, which should
594 /// be ignored in the vectorized loop body, this function records the
595 /// VectorLoopValue of the respective Phi also as the VectorLoopValue of the
596 /// cast. We had already proved that the casted Phi is equal to the uncasted
597 /// Phi in the vectorized loop (under a runtime guard), and therefore
598 /// there is no need to vectorize the cast - the same value can be used in the
599 /// vector loop for both the Phi and the cast.
600 /// If \p VectorLoopValue is a scalarized value, \p Lane is also specified,
601 /// Otherwise, \p VectorLoopValue is a widened/vectorized value.
602 void recordVectorLoopValueForInductionCast (const InductionDescriptor &ID,
603 Value *VectorLoopValue,
604 unsigned Part,
605 unsigned Lane = UINT_MAX(2147483647 *2U +1U));
606
607 /// Generate a shuffle sequence that will reverse the vector Vec.
608 virtual Value *reverseVector(Value *Vec);
609
610 /// Returns (and creates if needed) the original loop trip count.
611 Value *getOrCreateTripCount(Loop *NewLoop);
612
613 /// Returns (and creates if needed) the trip count of the widened loop.
614 Value *getOrCreateVectorTripCount(Loop *NewLoop);
615
616 /// Returns a bitcasted value to the requested vector type.
617 /// Also handles bitcasts of vector<float> <-> vector<pointer> types.
618 Value *createBitOrPointerCast(Value *V, VectorType *DstVTy,
619 const DataLayout &DL);
620
621 /// Emit a bypass check to see if the vector trip count is zero, including if
622 /// it overflows.
623 void emitMinimumIterationCountCheck(Loop *L, BasicBlock *Bypass);
624
625 /// Emit a bypass check to see if all of the SCEV assumptions we've
626 /// had to make are correct.
627 void emitSCEVChecks(Loop *L, BasicBlock *Bypass);
628
629 /// Emit bypass checks to check any memory assumptions we may have made.
630 void emitMemRuntimeChecks(Loop *L, BasicBlock *Bypass);
631
632 /// Add additional metadata to \p To that was not present on \p Orig.
633 ///
634 /// Currently this is used to add the noalias annotations based on the
635 /// inserted memchecks. Use this for instructions that are *cloned* into the
636 /// vector loop.
637 void addNewMetadata(Instruction *To, const Instruction *Orig);
638
639 /// Add metadata from one instruction to another.
640 ///
641 /// This includes both the original MDs from \p From and additional ones (\see
642 /// addNewMetadata). Use this for *newly created* instructions in the vector
643 /// loop.
644 void addMetadata(Instruction *To, Instruction *From);
645
646 /// \brief Similar to the previous function but it adds the metadata to a
647 /// vector of instructions.
648 void addMetadata(ArrayRef<Value *> To, Instruction *From);
649
650 /// The original loop.
651 Loop *OrigLoop;
652
653 /// A wrapper around ScalarEvolution used to add runtime SCEV checks. Applies
654 /// dynamic knowledge to simplify SCEV expressions and converts them to a
655 /// more usable form.
656 PredicatedScalarEvolution &PSE;
657
658 /// Loop Info.
659 LoopInfo *LI;
660
661 /// Dominator Tree.
662 DominatorTree *DT;
663
664 /// Alias Analysis.
665 AliasAnalysis *AA;
666
667 /// Target Library Info.
668 const TargetLibraryInfo *TLI;
669
670 /// Target Transform Info.
671 const TargetTransformInfo *TTI;
672
673 /// Assumption Cache.
674 AssumptionCache *AC;
675
676 /// Interface to emit optimization remarks.
677 OptimizationRemarkEmitter *ORE;
678
679 /// \brief LoopVersioning. It's only set up (non-null) if memchecks were
680 /// used.
681 ///
682 /// This is currently only used to add no-alias metadata based on the
683 /// memchecks. The actually versioning is performed manually.
684 std::unique_ptr<LoopVersioning> LVer;
685
686 /// The vectorization SIMD factor to use. Each vector will have this many
687 /// vector elements.
688 unsigned VF;
689
690 /// The vectorization unroll factor to use. Each scalar is vectorized to this
691 /// many different vector instructions.
692 unsigned UF;
693
694 /// The builder that we use
695 IRBuilder<> Builder;
696
697 // --- Vectorization state ---
698
699 /// The vector-loop preheader.
700 BasicBlock *LoopVectorPreHeader;
701
702 /// The scalar-loop preheader.
703 BasicBlock *LoopScalarPreHeader;
704
705 /// Middle Block between the vector and the scalar.
706 BasicBlock *LoopMiddleBlock;
707
708 /// The ExitBlock of the scalar loop.
709 BasicBlock *LoopExitBlock;
710
711 /// The vector loop body.
712 BasicBlock *LoopVectorBody;
713
714 /// The scalar loop body.
715 BasicBlock *LoopScalarBody;
716
717 /// A list of all bypass blocks. The first block is the entry of the loop.
718 SmallVector<BasicBlock *, 4> LoopBypassBlocks;
719
720 /// The new Induction variable which was added to the new block.
721 PHINode *Induction = nullptr;
722
723 /// The induction variable of the old basic block.
724 PHINode *OldInduction = nullptr;
725
726 /// Maps values from the original loop to their corresponding values in the
727 /// vectorized loop. A key value can map to either vector values, scalar
728 /// values or both kinds of values, depending on whether the key was
729 /// vectorized and scalarized.
730 VectorizerValueMap VectorLoopValueMap;
731
732 /// Store instructions that were predicated.
733 SmallVector<Instruction *, 4> PredicatedInstructions;
734
735 /// Trip count of the original loop.
736 Value *TripCount = nullptr;
737
738 /// Trip count of the widened loop (TripCount - TripCount % (VF*UF))
739 Value *VectorTripCount = nullptr;
740
741 /// The legality analysis.
742 LoopVectorizationLegality *Legal;
743
744 /// The profitablity analysis.
745 LoopVectorizationCostModel *Cost;
746
747 // Record whether runtime checks are added.
748 bool AddedSafetyChecks = false;
749
750 // Holds the end values for each induction variable. We save the end values
751 // so we can later fix-up the external users of the induction variables.
752 DenseMap<PHINode *, Value *> IVEndValues;
753};
754
755class InnerLoopUnroller : public InnerLoopVectorizer {
756public:
757 InnerLoopUnroller(Loop *OrigLoop, PredicatedScalarEvolution &PSE,
758 LoopInfo *LI, DominatorTree *DT,
759 const TargetLibraryInfo *TLI,
760 const TargetTransformInfo *TTI, AssumptionCache *AC,
761 OptimizationRemarkEmitter *ORE, unsigned UnrollFactor,
762 LoopVectorizationLegality *LVL,
763 LoopVectorizationCostModel *CM)
764 : InnerLoopVectorizer(OrigLoop, PSE, LI, DT, TLI, TTI, AC, ORE, 1,
765 UnrollFactor, LVL, CM) {}
766
767private:
768 Value *getBroadcastInstrs(Value *V) override;
769 Value *getStepVector(Value *Val, int StartIdx, Value *Step,
770 Instruction::BinaryOps Opcode =
771 Instruction::BinaryOpsEnd) override;
772 Value *reverseVector(Value *Vec) override;
773};
774
775} // end namespace llvm
776
777/// \brief Look for a meaningful debug location on the instruction or it's
778/// operands.
779static Instruction *getDebugLocFromInstOrOperands(Instruction *I) {
780 if (!I)
781 return I;
782
783 DebugLoc Empty;
784 if (I->getDebugLoc() != Empty)
785 return I;
786
787 for (User::op_iterator OI = I->op_begin(), OE = I->op_end(); OI != OE; ++OI) {
788 if (Instruction *OpInst = dyn_cast<Instruction>(*OI))
789 if (OpInst->getDebugLoc() != Empty)
790 return OpInst;
791 }
792
793 return I;
794}
795
796void InnerLoopVectorizer::setDebugLocFromInst(IRBuilder<> &B, const Value *Ptr) {
797 if (const Instruction *Inst = dyn_cast_or_null<Instruction>(Ptr)) {
798 const DILocation *DIL = Inst->getDebugLoc();
799 if (DIL && Inst->getFunction()->isDebugInfoForProfiling() &&
800 !isa<DbgInfoIntrinsic>(Inst))
801 B.SetCurrentDebugLocation(DIL->cloneWithDuplicationFactor(UF * VF));
802 else
803 B.SetCurrentDebugLocation(DIL);
804 } else
805 B.SetCurrentDebugLocation(DebugLoc());
806}
807
808#ifndef NDEBUG
809/// \return string containing a file name and a line # for the given loop.
810static std::string getDebugLocString(const Loop *L) {
811 std::string Result;
812 if (L) {
813 raw_string_ostream OS(Result);
814 if (const DebugLoc LoopDbgLoc = L->getStartLoc())
815 LoopDbgLoc.print(OS);
816 else
817 // Just print the module name.
818 OS << L->getHeader()->getParent()->getParent()->getModuleIdentifier();
819 OS.flush();
820 }
821 return Result;
822}
823#endif
824
825void InnerLoopVectorizer::addNewMetadata(Instruction *To,
826 const Instruction *Orig) {
827 // If the loop was versioned with memchecks, add the corresponding no-alias
828 // metadata.
829 if (LVer && (isa<LoadInst>(Orig) || isa<StoreInst>(Orig)))
830 LVer->annotateInstWithNoAlias(To, Orig);
831}
832
833void InnerLoopVectorizer::addMetadata(Instruction *To,
834 Instruction *From) {
835 propagateMetadata(To, From);
836 addNewMetadata(To, From);
837}
838
839void InnerLoopVectorizer::addMetadata(ArrayRef<Value *> To,
840 Instruction *From) {
841 for (Value *V : To) {
842 if (Instruction *I = dyn_cast<Instruction>(V))
843 addMetadata(I, From);
844 }
845}
846
847namespace llvm {
848
849/// \brief The group of interleaved loads/stores sharing the same stride and
850/// close to each other.
851///
852/// Each member in this group has an index starting from 0, and the largest
853/// index should be less than interleaved factor, which is equal to the absolute
854/// value of the access's stride.
855///
856/// E.g. An interleaved load group of factor 4:
857/// for (unsigned i = 0; i < 1024; i+=4) {
858/// a = A[i]; // Member of index 0
859/// b = A[i+1]; // Member of index 1
860/// d = A[i+3]; // Member of index 3
861/// ...
862/// }
863///
864/// An interleaved store group of factor 4:
865/// for (unsigned i = 0; i < 1024; i+=4) {
866/// ...
867/// A[i] = a; // Member of index 0
868/// A[i+1] = b; // Member of index 1
869/// A[i+2] = c; // Member of index 2
870/// A[i+3] = d; // Member of index 3
871/// }
872///
873/// Note: the interleaved load group could have gaps (missing members), but
874/// the interleaved store group doesn't allow gaps.
875class InterleaveGroup {
876public:
877 InterleaveGroup(Instruction *Instr, int Stride, unsigned Align)
878 : Align(Align), InsertPos(Instr) {
879 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 879, __extension__ __PRETTY_FUNCTION__))
;
880
881 Factor = std::abs(Stride);
882 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 882, __extension__ __PRETTY_FUNCTION__))
;
883
884 Reverse = Stride < 0;
885 Members[0] = Instr;
886 }
887
888 bool isReverse() const { return Reverse; }
889 unsigned getFactor() const { return Factor; }
890 unsigned getAlignment() const { return Align; }
891 unsigned getNumMembers() const { return Members.size(); }
892
893 /// \brief Try to insert a new member \p Instr with index \p Index and
894 /// alignment \p NewAlign. The index is related to the leader and it could be
895 /// negative if it is the new leader.
896 ///
897 /// \returns false if the instruction doesn't belong to the group.
898 bool insertMember(Instruction *Instr, int Index, unsigned NewAlign) {
899 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 899, __extension__ __PRETTY_FUNCTION__))
;
900
901 int Key = Index + SmallestKey;
902
903 // Skip if there is already a member with the same index.
904 if (Members.count(Key))
905 return false;
906
907 if (Key > LargestKey) {
908 // The largest index is always less than the interleave factor.
909 if (Index >= static_cast<int>(Factor))
910 return false;
911
912 LargestKey = Key;
913 } else if (Key < SmallestKey) {
914 // The largest index is always less than the interleave factor.
915 if (LargestKey - Key >= static_cast<int>(Factor))
916 return false;
917
918 SmallestKey = Key;
919 }
920
921 // It's always safe to select the minimum alignment.
922 Align = std::min(Align, NewAlign);
923 Members[Key] = Instr;
924 return true;
925 }
926
927 /// \brief Get the member with the given index \p Index
928 ///
929 /// \returns nullptr if contains no such member.
930 Instruction *getMember(unsigned Index) const {
931 int Key = SmallestKey + Index;
932 if (!Members.count(Key))
933 return nullptr;
934
935 return Members.find(Key)->second;
936 }
937
938 /// \brief Get the index for the given member. Unlike the key in the member
939 /// map, the index starts from 0.
940 unsigned getIndex(Instruction *Instr) const {
941 for (auto I : Members)
942 if (I.second == Instr)
943 return I.first - SmallestKey;
944
945 llvm_unreachable("InterleaveGroup contains no such member")::llvm::llvm_unreachable_internal("InterleaveGroup contains no such member"
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 945)
;
946 }
947
948 Instruction *getInsertPos() const { return InsertPos; }
949 void setInsertPos(Instruction *Inst) { InsertPos = Inst; }
950
951 /// Add metadata (e.g. alias info) from the instructions in this group to \p
952 /// NewInst.
953 ///
954 /// FIXME: this function currently does not add noalias metadata a'la
955 /// addNewMedata. To do that we need to compute the intersection of the
956 /// noalias info from all members.
957 void addMetadata(Instruction *NewInst) const {
958 SmallVector<Value *, 4> VL;
959 std::transform(Members.begin(), Members.end(), std::back_inserter(VL),
960 [](std::pair<int, Instruction *> p) { return p.second; });
961 propagateMetadata(NewInst, VL);
962 }
963
964private:
965 unsigned Factor; // Interleave Factor.
966 bool Reverse;
967 unsigned Align;
968 DenseMap<int, Instruction *> Members;
969 int SmallestKey = 0;
970 int LargestKey = 0;
971
972 // To avoid breaking dependences, vectorized instructions of an interleave
973 // group should be inserted at either the first load or the last store in
974 // program order.
975 //
976 // E.g. %even = load i32 // Insert Position
977 // %add = add i32 %even // Use of %even
978 // %odd = load i32
979 //
980 // store i32 %even
981 // %odd = add i32 // Def of %odd
982 // store i32 %odd // Insert Position
983 Instruction *InsertPos;
984};
985} // end namespace llvm
986
987namespace {
988
989/// \brief Drive the analysis of interleaved memory accesses in the loop.
990///
991/// Use this class to analyze interleaved accesses only when we can vectorize
992/// a loop. Otherwise it's meaningless to do analysis as the vectorization
993/// on interleaved accesses is unsafe.
994///
995/// The analysis collects interleave groups and records the relationships
996/// between the member and the group in a map.
997class InterleavedAccessInfo {
998public:
999 InterleavedAccessInfo(PredicatedScalarEvolution &PSE, Loop *L,
1000 DominatorTree *DT, LoopInfo *LI)
1001 : PSE(PSE), TheLoop(L), DT(DT), LI(LI) {}
1002
1003 ~InterleavedAccessInfo() {
1004 SmallSet<InterleaveGroup *, 4> DelSet;
1005 // Avoid releasing a pointer twice.
1006 for (auto &I : InterleaveGroupMap)
1007 DelSet.insert(I.second);
1008 for (auto *Ptr : DelSet)
1009 delete Ptr;
1010 }
1011
1012 /// \brief Analyze the interleaved accesses and collect them in interleave
1013 /// groups. Substitute symbolic strides using \p Strides.
1014 void analyzeInterleaving(const ValueToValueMap &Strides);
1015
1016 /// \brief Check if \p Instr belongs to any interleave group.
1017 bool isInterleaved(Instruction *Instr) const {
1018 return InterleaveGroupMap.count(Instr);
1019 }
1020
1021 /// \brief Get the interleave group that \p Instr belongs to.
1022 ///
1023 /// \returns nullptr if doesn't have such group.
1024 InterleaveGroup *getInterleaveGroup(Instruction *Instr) const {
1025 if (InterleaveGroupMap.count(Instr))
1026 return InterleaveGroupMap.find(Instr)->second;
1027 return nullptr;
1028 }
1029
1030 /// \brief Returns true if an interleaved group that may access memory
1031 /// out-of-bounds requires a scalar epilogue iteration for correctness.
1032 bool requiresScalarEpilogue() const { return RequiresScalarEpilogue; }
1033
1034 /// \brief Initialize the LoopAccessInfo used for dependence checking.
1035 void setLAI(const LoopAccessInfo *Info) { LAI = Info; }
1036
1037private:
1038 /// A wrapper around ScalarEvolution, used to add runtime SCEV checks.
1039 /// Simplifies SCEV expressions in the context of existing SCEV assumptions.
1040 /// The interleaved access analysis can also add new predicates (for example
1041 /// by versioning strides of pointers).
1042 PredicatedScalarEvolution &PSE;
1043
1044 Loop *TheLoop;
1045 DominatorTree *DT;
1046 LoopInfo *LI;
1047 const LoopAccessInfo *LAI = nullptr;
1048
1049 /// True if the loop may contain non-reversed interleaved groups with
1050 /// out-of-bounds accesses. We ensure we don't speculatively access memory
1051 /// out-of-bounds by executing at least one scalar epilogue iteration.
1052 bool RequiresScalarEpilogue = false;
1053
1054 /// Holds the relationships between the members and the interleave group.
1055 DenseMap<Instruction *, InterleaveGroup *> InterleaveGroupMap;
1056
1057 /// Holds dependences among the memory accesses in the loop. It maps a source
1058 /// access to a set of dependent sink accesses.
1059 DenseMap<Instruction *, SmallPtrSet<Instruction *, 2>> Dependences;
1060
1061 /// \brief The descriptor for a strided memory access.
1062 struct StrideDescriptor {
1063 StrideDescriptor() = default;
1064 StrideDescriptor(int64_t Stride, const SCEV *Scev, uint64_t Size,
1065 unsigned Align)
1066 : Stride(Stride), Scev(Scev), Size(Size), Align(Align) {}
1067
1068 // The access's stride. It is negative for a reverse access.
1069 int64_t Stride = 0;
1070
1071 // The scalar expression of this access.
1072 const SCEV *Scev = nullptr;
1073
1074 // The size of the memory object.
1075 uint64_t Size = 0;
1076
1077 // The alignment of this access.
1078 unsigned Align = 0;
1079 };
1080
1081 /// \brief A type for holding instructions and their stride descriptors.
1082 using StrideEntry = std::pair<Instruction *, StrideDescriptor>;
1083
1084 /// \brief Create a new interleave group with the given instruction \p Instr,
1085 /// stride \p Stride and alignment \p Align.
1086 ///
1087 /// \returns the newly created interleave group.
1088 InterleaveGroup *createInterleaveGroup(Instruction *Instr, int Stride,
1089 unsigned Align) {
1090 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1091, __extension__ __PRETTY_FUNCTION__))
1091 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1091, __extension__ __PRETTY_FUNCTION__))
;
1092 InterleaveGroupMap[Instr] = new InterleaveGroup(Instr, Stride, Align);
1093 return InterleaveGroupMap[Instr];
1094 }
1095
1096 /// \brief Release the group and remove all the relationships.
1097 void releaseGroup(InterleaveGroup *Group) {
1098 for (unsigned i = 0; i < Group->getFactor(); i++)
1099 if (Instruction *Member = Group->getMember(i))
1100 InterleaveGroupMap.erase(Member);
1101
1102 delete Group;
1103 }
1104
1105 /// \brief Collect all the accesses with a constant stride in program order.
1106 void collectConstStrideAccesses(
1107 MapVector<Instruction *, StrideDescriptor> &AccessStrideInfo,
1108 const ValueToValueMap &Strides);
1109
1110 /// \brief Returns true if \p Stride is allowed in an interleaved group.
1111 static bool isStrided(int Stride) {
1112 unsigned Factor = std::abs(Stride);
1113 return Factor >= 2 && Factor <= MaxInterleaveGroupFactor;
1114 }
1115
1116 /// \brief Returns true if \p BB is a predicated block.
1117 bool isPredicated(BasicBlock *BB) const {
1118 return LoopAccessInfo::blockNeedsPredication(BB, TheLoop, DT);
1119 }
1120
1121 /// \brief Returns true if LoopAccessInfo can be used for dependence queries.
1122 bool areDependencesValid() const {
1123 return LAI && LAI->getDepChecker().getDependences();
1124 }
1125
1126 /// \brief Returns true if memory accesses \p A and \p B can be reordered, if
1127 /// necessary, when constructing interleaved groups.
1128 ///
1129 /// \p A must precede \p B in program order. We return false if reordering is
1130 /// not necessary or is prevented because \p A and \p B may be dependent.
1131 bool canReorderMemAccessesForInterleavedGroups(StrideEntry *A,
1132 StrideEntry *B) const {
1133 // Code motion for interleaved accesses can potentially hoist strided loads
1134 // and sink strided stores. The code below checks the legality of the
1135 // following two conditions:
1136 //
1137 // 1. Potentially moving a strided load (B) before any store (A) that
1138 // precedes B, or
1139 //
1140 // 2. Potentially moving a strided store (A) after any load or store (B)
1141 // that A precedes.
1142 //
1143 // It's legal to reorder A and B if we know there isn't a dependence from A
1144 // to B. Note that this determination is conservative since some
1145 // dependences could potentially be reordered safely.
1146
1147 // A is potentially the source of a dependence.
1148 auto *Src = A->first;
1149 auto SrcDes = A->second;
1150
1151 // B is potentially the sink of a dependence.
1152 auto *Sink = B->first;
1153 auto SinkDes = B->second;
1154
1155 // Code motion for interleaved accesses can't violate WAR dependences.
1156 // Thus, reordering is legal if the source isn't a write.
1157 if (!Src->mayWriteToMemory())
1158 return true;
1159
1160 // At least one of the accesses must be strided.
1161 if (!isStrided(SrcDes.Stride) && !isStrided(SinkDes.Stride))
1162 return true;
1163
1164 // If dependence information is not available from LoopAccessInfo,
1165 // conservatively assume the instructions can't be reordered.
1166 if (!areDependencesValid())
1167 return false;
1168
1169 // If we know there is a dependence from source to sink, assume the
1170 // instructions can't be reordered. Otherwise, reordering is legal.
1171 return !Dependences.count(Src) || !Dependences.lookup(Src).count(Sink);
1172 }
1173
1174 /// \brief Collect the dependences from LoopAccessInfo.
1175 ///
1176 /// We process the dependences once during the interleaved access analysis to
1177 /// enable constant-time dependence queries.
1178 void collectDependences() {
1179 if (!areDependencesValid())
1180 return;
1181 auto *Deps = LAI->getDepChecker().getDependences();
1182 for (auto Dep : *Deps)
1183 Dependences[Dep.getSource(*LAI)].insert(Dep.getDestination(*LAI));
1184 }
1185};
1186
1187/// Utility class for getting and setting loop vectorizer hints in the form
1188/// of loop metadata.
1189/// This class keeps a number of loop annotations locally (as member variables)
1190/// and can, upon request, write them back as metadata on the loop. It will
1191/// initially scan the loop for existing metadata, and will update the local
1192/// values based on information in the loop.
1193/// We cannot write all values to metadata, as the mere presence of some info,
1194/// for example 'force', means a decision has been made. So, we need to be
1195/// careful NOT to add them if the user hasn't specifically asked so.
1196class LoopVectorizeHints {
1197 enum HintKind { HK_WIDTH, HK_UNROLL, HK_FORCE, HK_ISVECTORIZED };
1198
1199 /// Hint - associates name and validation with the hint value.
1200 struct Hint {
1201 const char *Name;
1202 unsigned Value; // This may have to change for non-numeric values.
1203 HintKind Kind;
1204
1205 Hint(const char *Name, unsigned Value, HintKind Kind)
1206 : Name(Name), Value(Value), Kind(Kind) {}
1207
1208 bool validate(unsigned Val) {
1209 switch (Kind) {
1210 case HK_WIDTH:
1211 return isPowerOf2_32(Val) && Val <= VectorizerParams::MaxVectorWidth;
1212 case HK_UNROLL:
1213 return isPowerOf2_32(Val) && Val <= MaxInterleaveFactor;
1214 case HK_FORCE:
1215 return (Val <= 1);
1216 case HK_ISVECTORIZED:
1217 return (Val==0 || Val==1);
1218 }
1219 return false;
1220 }
1221 };
1222
1223 /// Vectorization width.
1224 Hint Width;
1225
1226 /// Vectorization interleave factor.
1227 Hint Interleave;
1228
1229 /// Vectorization forced
1230 Hint Force;
1231
1232 /// Already Vectorized
1233 Hint IsVectorized;
1234
1235 /// Return the loop metadata prefix.
1236 static StringRef Prefix() { return "llvm.loop."; }
1237
1238 /// True if there is any unsafe math in the loop.
1239 bool PotentiallyUnsafe = false;
1240
1241public:
1242 enum ForceKind {
1243 FK_Undefined = -1, ///< Not selected.
1244 FK_Disabled = 0, ///< Forcing disabled.
1245 FK_Enabled = 1, ///< Forcing enabled.
1246 };
1247
1248 LoopVectorizeHints(const Loop *L, bool DisableInterleaving,
1249 OptimizationRemarkEmitter &ORE)
1250 : Width("vectorize.width", VectorizerParams::VectorizationFactor,
1251 HK_WIDTH),
1252 Interleave("interleave.count", DisableInterleaving, HK_UNROLL),
1253 Force("vectorize.enable", FK_Undefined, HK_FORCE),
1254 IsVectorized("isvectorized", 0, HK_ISVECTORIZED), TheLoop(L), ORE(ORE) {
1255 // Populate values with existing loop metadata.
1256 getHintsFromMetadata();
1257
1258 // force-vector-interleave overrides DisableInterleaving.
1259 if (VectorizerParams::isInterleaveForced())
1260 Interleave.Value = VectorizerParams::VectorizationInterleave;
1261
1262 if (IsVectorized.Value != 1)
1263 // If the vectorization width and interleaving count are both 1 then
1264 // consider the loop to have been already vectorized because there's
1265 // nothing more that we can do.
1266 IsVectorized.Value = Width.Value == 1 && Interleave.Value == 1;
1267 DEBUG(if (DisableInterleaving && Interleave.Value == 1) dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (DisableInterleaving && Interleave
.Value == 1) dbgs() << "LV: Interleaving disabled by the pass manager\n"
; } } while (false)
1268 << "LV: Interleaving disabled by the pass manager\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (DisableInterleaving && Interleave
.Value == 1) dbgs() << "LV: Interleaving disabled by the pass manager\n"
; } } while (false)
;
1269 }
1270
1271 /// Mark the loop L as already vectorized by setting the width to 1.
1272 void setAlreadyVectorized() {
1273 IsVectorized.Value = 1;
1274 Hint Hints[] = {IsVectorized};
1275 writeHintsToMetadata(Hints);
1276 }
1277
1278 bool allowVectorization(Function *F, Loop *L, bool AlwaysVectorize) const {
1279 if (getForce() == LoopVectorizeHints::FK_Disabled) {
1280 DEBUG(dbgs() << "LV: Not vectorizing: #pragma vectorize disable.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: #pragma vectorize disable.\n"
; } } while (false)
;
1281 emitRemarkWithHints();
1282 return false;
1283 }
1284
1285 if (!AlwaysVectorize && getForce() != LoopVectorizeHints::FK_Enabled) {
1286 DEBUG(dbgs() << "LV: Not vectorizing: No #pragma vectorize enable.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: No #pragma vectorize enable.\n"
; } } while (false)
;
1287 emitRemarkWithHints();
1288 return false;
1289 }
1290
1291 if (getIsVectorized() == 1) {
1292 DEBUG(dbgs() << "LV: Not vectorizing: Disabled/already vectorized.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: Disabled/already vectorized.\n"
; } } while (false)
;
1293 // FIXME: Add interleave.disable metadata. This will allow
1294 // vectorize.disable to be used without disabling the pass and errors
1295 // to differentiate between disabled vectorization and a width of 1.
1296 ORE.emit([&]() {
1297 return OptimizationRemarkAnalysis(vectorizeAnalysisPassName(),
1298 "AllDisabled", L->getStartLoc(),
1299 L->getHeader())
1300 << "loop not vectorized: vectorization and interleaving are "
1301 "explicitly disabled, or the loop has already been "
1302 "vectorized";
1303 });
1304 return false;
1305 }
1306
1307 return true;
1308 }
1309
1310 /// Dumps all the hint information.
1311 void emitRemarkWithHints() const {
1312 using namespace ore;
1313
1314 ORE.emit([&]() {
1315 if (Force.Value == LoopVectorizeHints::FK_Disabled)
1316 return OptimizationRemarkMissed(LV_NAME"loop-vectorize", "MissedExplicitlyDisabled",
1317 TheLoop->getStartLoc(),
1318 TheLoop->getHeader())
1319 << "loop not vectorized: vectorization is explicitly disabled";
1320 else {
1321 OptimizationRemarkMissed R(LV_NAME"loop-vectorize", "MissedDetails",
1322 TheLoop->getStartLoc(),
1323 TheLoop->getHeader());
1324 R << "loop not vectorized";
1325 if (Force.Value == LoopVectorizeHints::FK_Enabled) {
1326 R << " (Force=" << NV("Force", true);
1327 if (Width.Value != 0)
1328 R << ", Vector Width=" << NV("VectorWidth", Width.Value);
1329 if (Interleave.Value != 0)
1330 R << ", Interleave Count="
1331 << NV("InterleaveCount", Interleave.Value);
1332 R << ")";
1333 }
1334 return R;
1335 }
1336 });
1337 }
1338
1339 unsigned getWidth() const { return Width.Value; }
1340 unsigned getInterleave() const { return Interleave.Value; }
1341 unsigned getIsVectorized() const { return IsVectorized.Value; }
1342 enum ForceKind getForce() const { return (ForceKind)Force.Value; }
1343
1344 /// \brief If hints are provided that force vectorization, use the AlwaysPrint
1345 /// pass name to force the frontend to print the diagnostic.
1346 const char *vectorizeAnalysisPassName() const {
1347 if (getWidth() == 1)
1348 return LV_NAME"loop-vectorize";
1349 if (getForce() == LoopVectorizeHints::FK_Disabled)
1350 return LV_NAME"loop-vectorize";
1351 if (getForce() == LoopVectorizeHints::FK_Undefined && getWidth() == 0)
1352 return LV_NAME"loop-vectorize";
1353 return OptimizationRemarkAnalysis::AlwaysPrint;
1354 }
1355
1356 bool allowReordering() const {
1357 // When enabling loop hints are provided we allow the vectorizer to change
1358 // the order of operations that is given by the scalar loop. This is not
1359 // enabled by default because can be unsafe or inefficient. For example,
1360 // reordering floating-point operations will change the way round-off
1361 // error accumulates in the loop.
1362 return getForce() == LoopVectorizeHints::FK_Enabled || getWidth() > 1;
1363 }
1364
1365 bool isPotentiallyUnsafe() const {
1366 // Avoid FP vectorization if the target is unsure about proper support.
1367 // This may be related to the SIMD unit in the target not handling
1368 // IEEE 754 FP ops properly, or bad single-to-double promotions.
1369 // Otherwise, a sequence of vectorized loops, even without reduction,
1370 // could lead to different end results on the destination vectors.
1371 return getForce() != LoopVectorizeHints::FK_Enabled && PotentiallyUnsafe;
1372 }
1373
1374 void setPotentiallyUnsafe() { PotentiallyUnsafe = true; }
1375
1376private:
1377 /// Find hints specified in the loop metadata and update local values.
1378 void getHintsFromMetadata() {
1379 MDNode *LoopID = TheLoop->getLoopID();
1380 if (!LoopID)
1381 return;
1382
1383 // First operand should refer to the loop id itself.
1384 assert(LoopID->getNumOperands() > 0 && "requires at least one operand")(static_cast <bool> (LoopID->getNumOperands() > 0
&& "requires at least one operand") ? void (0) : __assert_fail
("LoopID->getNumOperands() > 0 && \"requires at least one operand\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1384, __extension__ __PRETTY_FUNCTION__))
;
1385 assert(LoopID->getOperand(0) == LoopID && "invalid loop id")(static_cast <bool> (LoopID->getOperand(0) == LoopID
&& "invalid loop id") ? void (0) : __assert_fail ("LoopID->getOperand(0) == LoopID && \"invalid loop id\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1385, __extension__ __PRETTY_FUNCTION__))
;
1386
1387 for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
1388 const MDString *S = nullptr;
1389 SmallVector<Metadata *, 4> Args;
1390
1391 // The expected hint is either a MDString or a MDNode with the first
1392 // operand a MDString.
1393 if (const MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i))) {
1394 if (!MD || MD->getNumOperands() == 0)
1395 continue;
1396 S = dyn_cast<MDString>(MD->getOperand(0));
1397 for (unsigned i = 1, ie = MD->getNumOperands(); i < ie; ++i)
1398 Args.push_back(MD->getOperand(i));
1399 } else {
1400 S = dyn_cast<MDString>(LoopID->getOperand(i));
1401 assert(Args.size() == 0 && "too many arguments for MDString")(static_cast <bool> (Args.size() == 0 && "too many arguments for MDString"
) ? void (0) : __assert_fail ("Args.size() == 0 && \"too many arguments for MDString\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1401, __extension__ __PRETTY_FUNCTION__))
;
1402 }
1403
1404 if (!S)
1405 continue;
1406
1407 // Check if the hint starts with the loop metadata prefix.
1408 StringRef Name = S->getString();
1409 if (Args.size() == 1)
1410 setHint(Name, Args[0]);
1411 }
1412 }
1413
1414 /// Checks string hint with one operand and set value if valid.
1415 void setHint(StringRef Name, Metadata *Arg) {
1416 if (!Name.startswith(Prefix()))
1417 return;
1418 Name = Name.substr(Prefix().size(), StringRef::npos);
1419
1420 const ConstantInt *C = mdconst::dyn_extract<ConstantInt>(Arg);
1421 if (!C)
1422 return;
1423 unsigned Val = C->getZExtValue();
1424
1425 Hint *Hints[] = {&Width, &Interleave, &Force, &IsVectorized};
1426 for (auto H : Hints) {
1427 if (Name == H->Name) {
1428 if (H->validate(Val))
1429 H->Value = Val;
1430 else
1431 DEBUG(dbgs() << "LV: ignoring invalid hint '" << Name << "'\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: ignoring invalid hint '"
<< Name << "'\n"; } } while (false)
;
1432 break;
1433 }
1434 }
1435 }
1436
1437 /// Create a new hint from name / value pair.
1438 MDNode *createHintMetadata(StringRef Name, unsigned V) const {
1439 LLVMContext &Context = TheLoop->getHeader()->getContext();
1440 Metadata *MDs[] = {MDString::get(Context, Name),
1441 ConstantAsMetadata::get(
1442 ConstantInt::get(Type::getInt32Ty(Context), V))};
1443 return MDNode::get(Context, MDs);
1444 }
1445
1446 /// Matches metadata with hint name.
1447 bool matchesHintMetadataName(MDNode *Node, ArrayRef<Hint> HintTypes) {
1448 MDString *Name = dyn_cast<MDString>(Node->getOperand(0));
1449 if (!Name)
1450 return false;
1451
1452 for (auto H : HintTypes)
1453 if (Name->getString().endswith(H.Name))
1454 return true;
1455 return false;
1456 }
1457
1458 /// Sets current hints into loop metadata, keeping other values intact.
1459 void writeHintsToMetadata(ArrayRef<Hint> HintTypes) {
1460 if (HintTypes.empty())
1461 return;
1462
1463 // Reserve the first element to LoopID (see below).
1464 SmallVector<Metadata *, 4> MDs(1);
1465 // If the loop already has metadata, then ignore the existing operands.
1466 MDNode *LoopID = TheLoop->getLoopID();
1467 if (LoopID) {
1468 for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
1469 MDNode *Node = cast<MDNode>(LoopID->getOperand(i));
1470 // If node in update list, ignore old value.
1471 if (!matchesHintMetadataName(Node, HintTypes))
1472 MDs.push_back(Node);
1473 }
1474 }
1475
1476 // Now, add the missing hints.
1477 for (auto H : HintTypes)
1478 MDs.push_back(createHintMetadata(Twine(Prefix(), H.Name).str(), H.Value));
1479
1480 // Replace current metadata node with new one.
1481 LLVMContext &Context = TheLoop->getHeader()->getContext();
1482 MDNode *NewLoopID = MDNode::get(Context, MDs);
1483 // Set operand 0 to refer to the loop id itself.
1484 NewLoopID->replaceOperandWith(0, NewLoopID);
1485
1486 TheLoop->setLoopID(NewLoopID);
1487 }
1488
1489 /// The loop these hints belong to.
1490 const Loop *TheLoop;
1491
1492 /// Interface to emit optimization remarks.
1493 OptimizationRemarkEmitter &ORE;
1494};
1495
1496} // end anonymous namespace
1497
1498static void emitMissedWarning(Function *F, Loop *L,
1499 const LoopVectorizeHints &LH,
1500 OptimizationRemarkEmitter *ORE) {
1501 LH.emitRemarkWithHints();
1502
1503 if (LH.getForce() == LoopVectorizeHints::FK_Enabled) {
1504 if (LH.getWidth() != 1)
1505 ORE->emit(DiagnosticInfoOptimizationFailure(
1506 DEBUG_TYPE"loop-vectorize", "FailedRequestedVectorization",
1507 L->getStartLoc(), L->getHeader())
1508 << "loop not vectorized: "
1509 << "failed explicitly specified loop vectorization");
1510 else if (LH.getInterleave() != 1)
1511 ORE->emit(DiagnosticInfoOptimizationFailure(
1512 DEBUG_TYPE"loop-vectorize", "FailedRequestedInterleaving", L->getStartLoc(),
1513 L->getHeader())
1514 << "loop not interleaved: "
1515 << "failed explicitly specified loop interleaving");
1516 }
1517}
1518
1519namespace llvm {
1520
1521/// LoopVectorizationLegality checks if it is legal to vectorize a loop, and
1522/// to what vectorization factor.
1523/// This class does not look at the profitability of vectorization, only the
1524/// legality. This class has two main kinds of checks:
1525/// * Memory checks - The code in canVectorizeMemory checks if vectorization
1526/// will change the order of memory accesses in a way that will change the
1527/// correctness of the program.
1528/// * Scalars checks - The code in canVectorizeInstrs and canVectorizeMemory
1529/// checks for a number of different conditions, such as the availability of a
1530/// single induction variable, that all types are supported and vectorize-able,
1531/// etc. This code reflects the capabilities of InnerLoopVectorizer.
1532/// This class is also used by InnerLoopVectorizer for identifying
1533/// induction variable and the different reduction variables.
1534class LoopVectorizationLegality {
1535public:
1536 LoopVectorizationLegality(
1537 Loop *L, PredicatedScalarEvolution &PSE, DominatorTree *DT,
1538 TargetLibraryInfo *TLI, AliasAnalysis *AA, Function *F,
1539 const TargetTransformInfo *TTI,
1540 std::function<const LoopAccessInfo &(Loop &)> *GetLAA, LoopInfo *LI,
1541 OptimizationRemarkEmitter *ORE, LoopVectorizationRequirements *R,
1542 LoopVectorizeHints *H, DemandedBits *DB, AssumptionCache *AC)
1543 : TheLoop(L), PSE(PSE), TLI(TLI), TTI(TTI), DT(DT), GetLAA(GetLAA),
1544 ORE(ORE), InterleaveInfo(PSE, L, DT, LI), Requirements(R), Hints(H),
1545 DB(DB), AC(AC) {}
1546
1547 /// ReductionList contains the reduction descriptors for all
1548 /// of the reductions that were found in the loop.
1549 using ReductionList = DenseMap<PHINode *, RecurrenceDescriptor>;
1550
1551 /// InductionList saves induction variables and maps them to the
1552 /// induction descriptor.
1553 using InductionList = MapVector<PHINode *, InductionDescriptor>;
1554
1555 /// RecurrenceSet contains the phi nodes that are recurrences other than
1556 /// inductions and reductions.
1557 using RecurrenceSet = SmallPtrSet<const PHINode *, 8>;
1558
1559 /// Returns true if it is legal to vectorize this loop.
1560 /// This does not mean that it is profitable to vectorize this
1561 /// loop, only that it is legal to do so.
1562 bool canVectorize();
1563
1564 /// Returns the primary induction variable.
1565 PHINode *getPrimaryInduction() { return PrimaryInduction; }
1566
1567 /// Returns the reduction variables found in the loop.
1568 ReductionList *getReductionVars() { return &Reductions; }
1569
1570 /// Returns the induction variables found in the loop.
1571 InductionList *getInductionVars() { return &Inductions; }
1572
1573 /// Return the first-order recurrences found in the loop.
1574 RecurrenceSet *getFirstOrderRecurrences() { return &FirstOrderRecurrences; }
1575
1576 /// Return the set of instructions to sink to handle first-order recurrences.
1577 DenseMap<Instruction *, Instruction *> &getSinkAfter() { return SinkAfter; }
1578
1579 /// Returns the widest induction type.
1580 Type *getWidestInductionType() { return WidestIndTy; }
1581
1582 /// Returns True if V is a Phi node of an induction variable in this loop.
1583 bool isInductionPhi(const Value *V);
1584
1585 /// Returns True if V is a cast that is part of an induction def-use chain,
1586 /// and had been proven to be redundant under a runtime guard (in other
1587 /// words, the cast has the same SCEV expression as the induction phi).
1588 bool isCastedInductionVariable(const Value *V);
1589
1590 /// Returns True if V can be considered as an induction variable in this
1591 /// loop. V can be the induction phi, or some redundant cast in the def-use
1592 /// chain of the inducion phi.
1593 bool isInductionVariable(const Value *V);
1594
1595 /// Returns True if PN is a reduction variable in this loop.
1596 bool isReductionVariable(PHINode *PN) { return Reductions.count(PN); }
1597
1598 /// Returns True if Phi is a first-order recurrence in this loop.
1599 bool isFirstOrderRecurrence(const PHINode *Phi);
1600
1601 /// Return true if the block BB needs to be predicated in order for the loop
1602 /// to be vectorized.
1603 bool blockNeedsPredication(BasicBlock *BB);
1604
1605 /// Check if this pointer is consecutive when vectorizing. This happens
1606 /// when the last index of the GEP is the induction variable, or that the
1607 /// pointer itself is an induction variable.
1608 /// This check allows us to vectorize A[idx] into a wide load/store.
1609 /// Returns:
1610 /// 0 - Stride is unknown or non-consecutive.
1611 /// 1 - Address is consecutive.
1612 /// -1 - Address is consecutive, and decreasing.
1613 /// NOTE: This method must only be used before modifying the original scalar
1614 /// loop. Do not use after invoking 'createVectorizedLoopSkeleton' (PR34965).
1615 int isConsecutivePtr(Value *Ptr);
1616
1617 /// Returns true if the value V is uniform within the loop.
1618 bool isUniform(Value *V);
1619
1620 /// Returns the information that we collected about runtime memory check.
1621 const RuntimePointerChecking *getRuntimePointerChecking() const {
1622 return LAI->getRuntimePointerChecking();
1623 }
1624
1625 const LoopAccessInfo *getLAI() const { return LAI; }
1626
1627 /// \brief Check if \p Instr belongs to any interleaved access group.
1628 bool isAccessInterleaved(Instruction *Instr) {
1629 return InterleaveInfo.isInterleaved(Instr);
1630 }
1631
1632 /// \brief Get the interleaved access group that \p Instr belongs to.
1633 const InterleaveGroup *getInterleavedAccessGroup(Instruction *Instr) {
1634 return InterleaveInfo.getInterleaveGroup(Instr);
1635 }
1636
1637 /// \brief Returns true if an interleaved group requires a scalar iteration
1638 /// to handle accesses with gaps.
1639 bool requiresScalarEpilogue() const {
1640 return InterleaveInfo.requiresScalarEpilogue();
1641 }
1642
1643 unsigned getMaxSafeDepDistBytes() { return LAI->getMaxSafeDepDistBytes(); }
1644
1645 uint64_t getMaxSafeRegisterWidth() const {
1646 return LAI->getDepChecker().getMaxSafeRegisterWidth();
1647 }
1648
1649 bool hasStride(Value *V) { return LAI->hasStride(V); }
1650
1651 /// Returns true if the target machine supports masked store operation
1652 /// for the given \p DataType and kind of access to \p Ptr.
1653 bool isLegalMaskedStore(Type *DataType, Value *Ptr) {
1654 return isConsecutivePtr(Ptr) && TTI->isLegalMaskedStore(DataType);
1655 }
1656
1657 /// Returns true if the target machine supports masked load operation
1658 /// for the given \p DataType and kind of access to \p Ptr.
1659 bool isLegalMaskedLoad(Type *DataType, Value *Ptr) {
1660 return isConsecutivePtr(Ptr) && TTI->isLegalMaskedLoad(DataType);
1661 }
1662
1663 /// Returns true if the target machine supports masked scatter operation
1664 /// for the given \p DataType.
1665 bool isLegalMaskedScatter(Type *DataType) {
1666 return TTI->isLegalMaskedScatter(DataType);
1667 }
1668
1669 /// Returns true if the target machine supports masked gather operation
1670 /// for the given \p DataType.
1671 bool isLegalMaskedGather(Type *DataType) {
1672 return TTI->isLegalMaskedGather(DataType);
1673 }
1674
1675 /// Returns true if the target machine can represent \p V as a masked gather
1676 /// or scatter operation.
1677 bool isLegalGatherOrScatter(Value *V) {
1678 auto *LI = dyn_cast<LoadInst>(V);
1679 auto *SI = dyn_cast<StoreInst>(V);
1680 if (!LI && !SI)
1681 return false;
1682 auto *Ptr = getPointerOperand(V);
1683 auto *Ty = cast<PointerType>(Ptr->getType())->getElementType();
1684 return (LI && isLegalMaskedGather(Ty)) || (SI && isLegalMaskedScatter(Ty));
1685 }
1686
1687 /// Returns true if vector representation of the instruction \p I
1688 /// requires mask.
1689 bool isMaskRequired(const Instruction *I) { return (MaskedOp.count(I) != 0); }
1690
1691 unsigned getNumStores() const { return LAI->getNumStores(); }
1692 unsigned getNumLoads() const { return LAI->getNumLoads(); }
1693 unsigned getNumPredStores() const { return NumPredStores; }
1694
1695 /// Returns true if \p I is an instruction that will be scalarized with
1696 /// predication. Such instructions include conditional stores and
1697 /// instructions that may divide by zero.
1698 bool isScalarWithPredication(Instruction *I);
1699
1700 /// Returns true if \p I is a memory instruction with consecutive memory
1701 /// access that can be widened.
1702 bool memoryInstructionCanBeWidened(Instruction *I, unsigned VF = 1);
1703
1704 // Returns true if the NoNaN attribute is set on the function.
1705 bool hasFunNoNaNAttr() const { return HasFunNoNaNAttr; }
1706
1707private:
1708 /// Check if a single basic block loop is vectorizable.
1709 /// At this point we know that this is a loop with a constant trip count
1710 /// and we only need to check individual instructions.
1711 bool canVectorizeInstrs();
1712
1713 /// When we vectorize loops we may change the order in which
1714 /// we read and write from memory. This method checks if it is
1715 /// legal to vectorize the code, considering only memory constrains.
1716 /// Returns true if the loop is vectorizable
1717 bool canVectorizeMemory();
1718
1719 /// Return true if we can vectorize this loop using the IF-conversion
1720 /// transformation.
1721 bool canVectorizeWithIfConvert();
1722
1723 /// Return true if all of the instructions in the block can be speculatively
1724 /// executed. \p SafePtrs is a list of addresses that are known to be legal
1725 /// and we know that we can read from them without segfault.
1726 bool blockCanBePredicated(BasicBlock *BB, SmallPtrSetImpl<Value *> &SafePtrs);
1727
1728 /// Updates the vectorization state by adding \p Phi to the inductions list.
1729 /// This can set \p Phi as the main induction of the loop if \p Phi is a
1730 /// better choice for the main induction than the existing one.
1731 void addInductionPhi(PHINode *Phi, const InductionDescriptor &ID,
1732 SmallPtrSetImpl<Value *> &AllowedExit);
1733
1734 /// Create an analysis remark that explains why vectorization failed
1735 ///
1736 /// \p RemarkName is the identifier for the remark. If \p I is passed it is
1737 /// an instruction that prevents vectorization. Otherwise the loop is used
1738 /// for the location of the remark. \return the remark object that can be
1739 /// streamed to.
1740 OptimizationRemarkAnalysis
1741 createMissedAnalysis(StringRef RemarkName, Instruction *I = nullptr) const {
1742 return ::createMissedAnalysis(Hints->vectorizeAnalysisPassName(),
1743 RemarkName, TheLoop, I);
1744 }
1745
1746 /// \brief If an access has a symbolic strides, this maps the pointer value to
1747 /// the stride symbol.
1748 const ValueToValueMap *getSymbolicStrides() {
1749 // FIXME: Currently, the set of symbolic strides is sometimes queried before
1750 // it's collected. This happens from canVectorizeWithIfConvert, when the
1751 // pointer is checked to reference consecutive elements suitable for a
1752 // masked access.
1753 return LAI ? &LAI->getSymbolicStrides() : nullptr;
1754 }
1755
1756 unsigned NumPredStores = 0;
1757
1758 /// The loop that we evaluate.
1759 Loop *TheLoop;
1760
1761 /// A wrapper around ScalarEvolution used to add runtime SCEV checks.
1762 /// Applies dynamic knowledge to simplify SCEV expressions in the context
1763 /// of existing SCEV assumptions. The analysis will also add a minimal set
1764 /// of new predicates if this is required to enable vectorization and
1765 /// unrolling.
1766 PredicatedScalarEvolution &PSE;
1767
1768 /// Target Library Info.
1769 TargetLibraryInfo *TLI;
1770
1771 /// Target Transform Info
1772 const TargetTransformInfo *TTI;
1773
1774 /// Dominator Tree.
1775 DominatorTree *DT;
1776
1777 // LoopAccess analysis.
1778 std::function<const LoopAccessInfo &(Loop &)> *GetLAA;
1779
1780 // And the loop-accesses info corresponding to this loop. This pointer is
1781 // null until canVectorizeMemory sets it up.
1782 const LoopAccessInfo *LAI = nullptr;
1783
1784 /// Interface to emit optimization remarks.
1785 OptimizationRemarkEmitter *ORE;
1786
1787 /// The interleave access information contains groups of interleaved accesses
1788 /// with the same stride and close to each other.
1789 InterleavedAccessInfo InterleaveInfo;
1790
1791 // --- vectorization state --- //
1792
1793 /// Holds the primary induction variable. This is the counter of the
1794 /// loop.
1795 PHINode *PrimaryInduction = nullptr;
1796
1797 /// Holds the reduction variables.
1798 ReductionList Reductions;
1799
1800 /// Holds all of the induction variables that we found in the loop.
1801 /// Notice that inductions don't need to start at zero and that induction
1802 /// variables can be pointers.
1803 InductionList Inductions;
1804
1805 /// Holds all the casts that participate in the update chain of the induction
1806 /// variables, and that have been proven to be redundant (possibly under a
1807 /// runtime guard). These casts can be ignored when creating the vectorized
1808 /// loop body.
1809 SmallPtrSet<Instruction *, 4> InductionCastsToIgnore;
1810
1811 /// Holds the phi nodes that are first-order recurrences.
1812 RecurrenceSet FirstOrderRecurrences;
1813
1814 /// Holds instructions that need to sink past other instructions to handle
1815 /// first-order recurrences.
1816 DenseMap<Instruction *, Instruction *> SinkAfter;
1817
1818 /// Holds the widest induction type encountered.
1819 Type *WidestIndTy = nullptr;
1820
1821 /// Allowed outside users. This holds the induction and reduction
1822 /// vars which can be accessed from outside the loop.
1823 SmallPtrSet<Value *, 4> AllowedExit;
1824
1825 /// Can we assume the absence of NaNs.
1826 bool HasFunNoNaNAttr = false;
1827
1828 /// Vectorization requirements that will go through late-evaluation.
1829 LoopVectorizationRequirements *Requirements;
1830
1831 /// Used to emit an analysis of any legality issues.
1832 LoopVectorizeHints *Hints;
1833
1834 /// The demanded bits analsyis is used to compute the minimum type size in
1835 /// which a reduction can be computed.
1836 DemandedBits *DB;
1837
1838 /// The assumption cache analysis is used to compute the minimum type size in
1839 /// which a reduction can be computed.
1840 AssumptionCache *AC;
1841
1842 /// While vectorizing these instructions we have to generate a
1843 /// call to the appropriate masked intrinsic
1844 SmallPtrSet<const Instruction *, 8> MaskedOp;
1845};
1846
1847/// LoopVectorizationCostModel - estimates the expected speedups due to
1848/// vectorization.
1849/// In many cases vectorization is not profitable. This can happen because of
1850/// a number of reasons. In this class we mainly attempt to predict the
1851/// expected speedup/slowdowns due to the supported instruction set. We use the
1852/// TargetTransformInfo to query the different backends for the cost of
1853/// different operations.
1854class LoopVectorizationCostModel {
1855public:
1856 LoopVectorizationCostModel(Loop *L, PredicatedScalarEvolution &PSE,
1857 LoopInfo *LI, LoopVectorizationLegality *Legal,
1858 const TargetTransformInfo &TTI,
1859 const TargetLibraryInfo *TLI, DemandedBits *DB,
1860 AssumptionCache *AC,
1861 OptimizationRemarkEmitter *ORE, const Function *F,
1862 const LoopVectorizeHints *Hints)
1863 : TheLoop(L), PSE(PSE), LI(LI), Legal(Legal), TTI(TTI), TLI(TLI), DB(DB),
1864 AC(AC), ORE(ORE), TheFunction(F), Hints(Hints) {}
1865
1866 /// \return An upper bound for the vectorization factor, or None if
1867 /// vectorization should be avoided up front.
1868 Optional<unsigned> computeMaxVF(bool OptForSize);
1869
1870 /// \return The most profitable vectorization factor and the cost of that VF.
1871 /// This method checks every power of two up to MaxVF. If UserVF is not ZERO
1872 /// then this vectorization factor will be selected if vectorization is
1873 /// possible.
1874 VectorizationFactor selectVectorizationFactor(unsigned MaxVF);
1875
1876 /// Setup cost-based decisions for user vectorization factor.
1877 void selectUserVectorizationFactor(unsigned UserVF) {
1878 collectUniformsAndScalars(UserVF);
1879 collectInstsToScalarize(UserVF);
1880 }
1881
1882 /// \return The size (in bits) of the smallest and widest types in the code
1883 /// that needs to be vectorized. We ignore values that remain scalar such as
1884 /// 64 bit loop indices.
1885 std::pair<unsigned, unsigned> getSmallestAndWidestTypes();
1886
1887 /// \return The desired interleave count.
1888 /// If interleave count has been specified by metadata it will be returned.
1889 /// Otherwise, the interleave count is computed and returned. VF and LoopCost
1890 /// are the selected vectorization factor and the cost of the selected VF.
1891 unsigned selectInterleaveCount(bool OptForSize, unsigned VF,
1892 unsigned LoopCost);
1893
1894 /// Memory access instruction may be vectorized in more than one way.
1895 /// Form of instruction after vectorization depends on cost.
1896 /// This function takes cost-based decisions for Load/Store instructions
1897 /// and collects them in a map. This decisions map is used for building
1898 /// the lists of loop-uniform and loop-scalar instructions.
1899 /// The calculated cost is saved with widening decision in order to
1900 /// avoid redundant calculations.
1901 void setCostBasedWideningDecision(unsigned VF);
1902
1903 /// \brief A struct that represents some properties of the register usage
1904 /// of a loop.
1905 struct RegisterUsage {
1906 /// Holds the number of loop invariant values that are used in the loop.
1907 unsigned LoopInvariantRegs;
1908
1909 /// Holds the maximum number of concurrent live intervals in the loop.
1910 unsigned MaxLocalUsers;
1911
1912 /// Holds the number of instructions in the loop.
1913 unsigned NumInstructions;
1914 };
1915
1916 /// \return Returns information about the register usages of the loop for the
1917 /// given vectorization factors.
1918 SmallVector<RegisterUsage, 8> calculateRegisterUsage(ArrayRef<unsigned> VFs);
1919
1920 /// Collect values we want to ignore in the cost model.
1921 void collectValuesToIgnore();
1922
1923 /// \returns The smallest bitwidth each instruction can be represented with.
1924 /// The vector equivalents of these instructions should be truncated to this
1925 /// type.
1926 const MapVector<Instruction *, uint64_t> &getMinimalBitwidths() const {
1927 return MinBWs;
1928 }
1929
1930 /// \returns True if it is more profitable to scalarize instruction \p I for
1931 /// vectorization factor \p VF.
1932 bool isProfitableToScalarize(Instruction *I, unsigned VF) const {
1933 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1933, __extension__ __PRETTY_FUNCTION__))
;
1934 auto Scalars = InstsToScalarize.find(VF);
1935 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1936, __extension__ __PRETTY_FUNCTION__))
1936 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1936, __extension__ __PRETTY_FUNCTION__))
;
1937 return Scalars->second.count(I);
1938 }
1939
1940 /// Returns true if \p I is known to be uniform after vectorization.
1941 bool isUniformAfterVectorization(Instruction *I, unsigned VF) const {
1942 if (VF == 1)
1943 return true;
1944 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1944, __extension__ __PRETTY_FUNCTION__))
;
1945 auto UniformsPerVF = Uniforms.find(VF);
1946 return UniformsPerVF->second.count(I);
1947 }
1948
1949 /// Returns true if \p I is known to be scalar after vectorization.
1950 bool isScalarAfterVectorization(Instruction *I, unsigned VF) const {
1951 if (VF == 1)
1952 return true;
1953 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1953, __extension__ __PRETTY_FUNCTION__))
;
1954 auto ScalarsPerVF = Scalars.find(VF);
1955 return ScalarsPerVF->second.count(I);
1956 }
1957
1958 /// \returns True if instruction \p I can be truncated to a smaller bitwidth
1959 /// for vectorization factor \p VF.
1960 bool canTruncateToMinimalBitwidth(Instruction *I, unsigned VF) const {
1961 return VF > 1 && MinBWs.count(I) && !isProfitableToScalarize(I, VF) &&
1962 !isScalarAfterVectorization(I, VF);
1963 }
1964
1965 /// Decision that was taken during cost calculation for memory instruction.
1966 enum InstWidening {
1967 CM_Unknown,
1968 CM_Widen, // For consecutive accesses with stride +1.
1969 CM_Widen_Reverse, // For consecutive accesses with stride -1.
1970 CM_Interleave,
1971 CM_GatherScatter,
1972 CM_Scalarize
1973 };
1974
1975 /// Save vectorization decision \p W and \p Cost taken by the cost model for
1976 /// instruction \p I and vector width \p VF.
1977 void setWideningDecision(Instruction *I, unsigned VF, InstWidening W,
1978 unsigned Cost) {
1979 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1979, __extension__ __PRETTY_FUNCTION__))
;
1980 WideningDecisions[std::make_pair(I, VF)] = std::make_pair(W, Cost);
1981 }
1982
1983 /// Save vectorization decision \p W and \p Cost taken by the cost model for
1984 /// interleaving group \p Grp and vector width \p VF.
1985 void setWideningDecision(const InterleaveGroup *Grp, unsigned VF,
1986 InstWidening W, unsigned Cost) {
1987 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 1987, __extension__ __PRETTY_FUNCTION__))
;
1988 /// Broadcast this decicion to all instructions inside the group.
1989 /// But the cost will be assigned to one instruction only.
1990 for (unsigned i = 0; i < Grp->getFactor(); ++i) {
1991 if (auto *I = Grp->getMember(i)) {
1992 if (Grp->getInsertPos() == I)
1993 WideningDecisions[std::make_pair(I, VF)] = std::make_pair(W, Cost);
1994 else
1995 WideningDecisions[std::make_pair(I, VF)] = std::make_pair(W, 0);
1996 }
1997 }
1998 }
1999
2000 /// Return the cost model decision for the given instruction \p I and vector
2001 /// width \p VF. Return CM_Unknown if this instruction did not pass
2002 /// through the cost modeling.
2003 InstWidening getWideningDecision(Instruction *I, unsigned VF) {
2004 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2004, __extension__ __PRETTY_FUNCTION__))
;
2005 std::pair<Instruction *, unsigned> InstOnVF = std::make_pair(I, VF);
2006 auto Itr = WideningDecisions.find(InstOnVF);
2007 if (Itr == WideningDecisions.end())
2008 return CM_Unknown;
2009 return Itr->second.first;
2010 }
2011
2012 /// Return the vectorization cost for the given instruction \p I and vector
2013 /// width \p VF.
2014 unsigned getWideningCost(Instruction *I, unsigned VF) {
2015 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2015, __extension__ __PRETTY_FUNCTION__))
;
2016 std::pair<Instruction *, unsigned> InstOnVF = std::make_pair(I, VF);
2017 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2017, __extension__ __PRETTY_FUNCTION__))
;
2018 return WideningDecisions[InstOnVF].second;
2019 }
2020
2021 /// Return True if instruction \p I is an optimizable truncate whose operand
2022 /// is an induction variable. Such a truncate will be removed by adding a new
2023 /// induction variable with the destination type.
2024 bool isOptimizableIVTruncate(Instruction *I, unsigned VF) {
2025 // If the instruction is not a truncate, return false.
2026 auto *Trunc = dyn_cast<TruncInst>(I);
2027 if (!Trunc)
2028 return false;
2029
2030 // Get the source and destination types of the truncate.
2031 Type *SrcTy = ToVectorTy(cast<CastInst>(I)->getSrcTy(), VF);
2032 Type *DestTy = ToVectorTy(cast<CastInst>(I)->getDestTy(), VF);
2033
2034 // If the truncate is free for the given types, return false. Replacing a
2035 // free truncate with an induction variable would add an induction variable
2036 // update instruction to each iteration of the loop. We exclude from this
2037 // check the primary induction variable since it will need an update
2038 // instruction regardless.
2039 Value *Op = Trunc->getOperand(0);
2040 if (Op != Legal->getPrimaryInduction() && TTI.isTruncateFree(SrcTy, DestTy))
2041 return false;
2042
2043 // If the truncated value is not an induction variable, return false.
2044 return Legal->isInductionPhi(Op);
2045 }
2046
2047 /// Collects the instructions to scalarize for each predicated instruction in
2048 /// the loop.
2049 void collectInstsToScalarize(unsigned VF);
2050
2051 /// Collect Uniform and Scalar values for the given \p VF.
2052 /// The sets depend on CM decision for Load/Store instructions
2053 /// that may be vectorized as interleave, gather-scatter or scalarized.
2054 void collectUniformsAndScalars(unsigned VF) {
2055 // Do the analysis once.
2056 if (VF == 1 || Uniforms.count(VF))
2057 return;
2058 setCostBasedWideningDecision(VF);
2059 collectLoopUniforms(VF);
2060 collectLoopScalars(VF);
2061 }
2062
2063private:
2064 /// \return An upper bound for the vectorization factor, larger than zero.
2065 /// One is returned if vectorization should best be avoided due to cost.
2066 unsigned computeFeasibleMaxVF(bool OptForSize, unsigned ConstTripCount);
2067
2068 /// The vectorization cost is a combination of the cost itself and a boolean
2069 /// indicating whether any of the contributing operations will actually
2070 /// operate on
2071 /// vector values after type legalization in the backend. If this latter value
2072 /// is
2073 /// false, then all operations will be scalarized (i.e. no vectorization has
2074 /// actually taken place).
2075 using VectorizationCostTy = std::pair<unsigned, bool>;
2076
2077 /// Returns the expected execution cost. The unit of the cost does
2078 /// not matter because we use the 'cost' units to compare different
2079 /// vector widths. The cost that is returned is *not* normalized by
2080 /// the factor width.
2081 VectorizationCostTy expectedCost(unsigned VF);
2082
2083 /// Returns the execution time cost of an instruction for a given vector
2084 /// width. Vector width of one means scalar.
2085 VectorizationCostTy getInstructionCost(Instruction *I, unsigned VF);
2086
2087 /// The cost-computation logic from getInstructionCost which provides
2088 /// the vector type as an output parameter.
2089 unsigned getInstructionCost(Instruction *I, unsigned VF, Type *&VectorTy);
2090
2091 /// Calculate vectorization cost of memory instruction \p I.
2092 unsigned getMemoryInstructionCost(Instruction *I, unsigned VF);
2093
2094 /// The cost computation for scalarized memory instruction.
2095 unsigned getMemInstScalarizationCost(Instruction *I, unsigned VF);
2096
2097 /// The cost computation for interleaving group of memory instructions.
2098 unsigned getInterleaveGroupCost(Instruction *I, unsigned VF);
2099
2100 /// The cost computation for Gather/Scatter instruction.
2101 unsigned getGatherScatterCost(Instruction *I, unsigned VF);
2102
2103 /// The cost computation for widening instruction \p I with consecutive
2104 /// memory access.
2105 unsigned getConsecutiveMemOpCost(Instruction *I, unsigned VF);
2106
2107 /// The cost calculation for Load instruction \p I with uniform pointer -
2108 /// scalar load + broadcast.
2109 unsigned getUniformMemOpCost(Instruction *I, unsigned VF);
2110
2111 /// Returns whether the instruction is a load or store and will be a emitted
2112 /// as a vector operation.
2113 bool isConsecutiveLoadOrStore(Instruction *I);
2114
2115 /// Create an analysis remark that explains why vectorization failed
2116 ///
2117 /// \p RemarkName is the identifier for the remark. \return the remark object
2118 /// that can be streamed to.
2119 OptimizationRemarkAnalysis createMissedAnalysis(StringRef RemarkName) {
2120 return ::createMissedAnalysis(Hints->vectorizeAnalysisPassName(),
2121 RemarkName, TheLoop);
2122 }
2123
2124 /// Map of scalar integer values to the smallest bitwidth they can be legally
2125 /// represented as. The vector equivalents of these values should be truncated
2126 /// to this type.
2127 MapVector<Instruction *, uint64_t> MinBWs;
2128
2129 /// A type representing the costs for instructions if they were to be
2130 /// scalarized rather than vectorized. The entries are Instruction-Cost
2131 /// pairs.
2132 using ScalarCostsTy = DenseMap<Instruction *, unsigned>;
2133
2134 /// A set containing all BasicBlocks that are known to present after
2135 /// vectorization as a predicated block.
2136 SmallPtrSet<BasicBlock *, 4> PredicatedBBsAfterVectorization;
2137
2138 /// A map holding scalar costs for different vectorization factors. The
2139 /// presence of a cost for an instruction in the mapping indicates that the
2140 /// instruction will be scalarized when vectorizing with the associated
2141 /// vectorization factor. The entries are VF-ScalarCostTy pairs.
2142 DenseMap<unsigned, ScalarCostsTy> InstsToScalarize;
2143
2144 /// Holds the instructions known to be uniform after vectorization.
2145 /// The data is collected per VF.
2146 DenseMap<unsigned, SmallPtrSet<Instruction *, 4>> Uniforms;
2147
2148 /// Holds the instructions known to be scalar after vectorization.
2149 /// The data is collected per VF.
2150 DenseMap<unsigned, SmallPtrSet<Instruction *, 4>> Scalars;
2151
2152 /// Holds the instructions (address computations) that are forced to be
2153 /// scalarized.
2154 DenseMap<unsigned, SmallPtrSet<Instruction *, 4>> ForcedScalars;
2155
2156 /// Returns the expected difference in cost from scalarizing the expression
2157 /// feeding a predicated instruction \p PredInst. The instructions to
2158 /// scalarize and their scalar costs are collected in \p ScalarCosts. A
2159 /// non-negative return value implies the expression will be scalarized.
2160 /// Currently, only single-use chains are considered for scalarization.
2161 int computePredInstDiscount(Instruction *PredInst, ScalarCostsTy &ScalarCosts,
2162 unsigned VF);
2163
2164 /// Collect the instructions that are uniform after vectorization. An
2165 /// instruction is uniform if we represent it with a single scalar value in
2166 /// the vectorized loop corresponding to each vector iteration. Examples of
2167 /// uniform instructions include pointer operands of consecutive or
2168 /// interleaved memory accesses. Note that although uniformity implies an
2169 /// instruction will be scalar, the reverse is not true. In general, a
2170 /// scalarized instruction will be represented by VF scalar values in the
2171 /// vectorized loop, each corresponding to an iteration of the original
2172 /// scalar loop.
2173 void collectLoopUniforms(unsigned VF);
2174
2175 /// Collect the instructions that are scalar after vectorization. An
2176 /// instruction is scalar if it is known to be uniform or will be scalarized
2177 /// during vectorization. Non-uniform scalarized instructions will be
2178 /// represented by VF values in the vectorized loop, each corresponding to an
2179 /// iteration of the original scalar loop.
2180 void collectLoopScalars(unsigned VF);
2181
2182 /// Keeps cost model vectorization decision and cost for instructions.
2183 /// Right now it is used for memory instructions only.
2184 using DecisionList = DenseMap<std::pair<Instruction *, unsigned>,
2185 std::pair<InstWidening, unsigned>>;
2186
2187 DecisionList WideningDecisions;
2188
2189public:
2190 /// The loop that we evaluate.
2191 Loop *TheLoop;
2192
2193 /// Predicated scalar evolution analysis.
2194 PredicatedScalarEvolution &PSE;
2195
2196 /// Loop Info analysis.
2197 LoopInfo *LI;
2198
2199 /// Vectorization legality.
2200 LoopVectorizationLegality *Legal;
2201
2202 /// Vector target information.
2203 const TargetTransformInfo &TTI;
2204
2205 /// Target Library Info.
2206 const TargetLibraryInfo *TLI;
2207
2208 /// Demanded bits analysis.
2209 DemandedBits *DB;
2210
2211 /// Assumption cache.
2212 AssumptionCache *AC;
2213
2214 /// Interface to emit optimization remarks.
2215 OptimizationRemarkEmitter *ORE;
2216
2217 const Function *TheFunction;
2218
2219 /// Loop Vectorize Hint.
2220 const LoopVectorizeHints *Hints;
2221
2222 /// Values to ignore in the cost model.
2223 SmallPtrSet<const Value *, 16> ValuesToIgnore;
2224
2225 /// Values to ignore in the cost model when VF > 1.
2226 SmallPtrSet<const Value *, 16> VecValuesToIgnore;
2227};
2228
2229} // end namespace llvm
2230
2231namespace {
2232
2233/// \brief This holds vectorization requirements that must be verified late in
2234/// the process. The requirements are set by legalize and costmodel. Once
2235/// vectorization has been determined to be possible and profitable the
2236/// requirements can be verified by looking for metadata or compiler options.
2237/// For example, some loops require FP commutativity which is only allowed if
2238/// vectorization is explicitly specified or if the fast-math compiler option
2239/// has been provided.
2240/// Late evaluation of these requirements allows helpful diagnostics to be
2241/// composed that tells the user what need to be done to vectorize the loop. For
2242/// example, by specifying #pragma clang loop vectorize or -ffast-math. Late
2243/// evaluation should be used only when diagnostics can generated that can be
2244/// followed by a non-expert user.
2245class LoopVectorizationRequirements {
2246public:
2247 LoopVectorizationRequirements(OptimizationRemarkEmitter &ORE) : ORE(ORE) {}
2248
2249 void addUnsafeAlgebraInst(Instruction *I) {
2250 // First unsafe algebra instruction.
2251 if (!UnsafeAlgebraInst)
2252 UnsafeAlgebraInst = I;
2253 }
2254
2255 void addRuntimePointerChecks(unsigned Num) { NumRuntimePointerChecks = Num; }
2256
2257 bool doesNotMeet(Function *F, Loop *L, const LoopVectorizeHints &Hints) {
2258 const char *PassName = Hints.vectorizeAnalysisPassName();
2259 bool Failed = false;
2260 if (UnsafeAlgebraInst && !Hints.allowReordering()) {
2261 ORE.emit([&]() {
2262 return OptimizationRemarkAnalysisFPCommute(
2263 PassName, "CantReorderFPOps",
2264 UnsafeAlgebraInst->getDebugLoc(),
2265 UnsafeAlgebraInst->getParent())
2266 << "loop not vectorized: cannot prove it is safe to reorder "
2267 "floating-point operations";
2268 });
2269 Failed = true;
2270 }
2271
2272 // Test if runtime memcheck thresholds are exceeded.
2273 bool PragmaThresholdReached =
2274 NumRuntimePointerChecks > PragmaVectorizeMemoryCheckThreshold;
2275 bool ThresholdReached =
2276 NumRuntimePointerChecks > VectorizerParams::RuntimeMemoryCheckThreshold;
2277 if ((ThresholdReached && !Hints.allowReordering()) ||
2278 PragmaThresholdReached) {
2279 ORE.emit([&]() {
2280 return OptimizationRemarkAnalysisAliasing(PassName, "CantReorderMemOps",
2281 L->getStartLoc(),
2282 L->getHeader())
2283 << "loop not vectorized: cannot prove it is safe to reorder "
2284 "memory operations";
2285 });
2286 DEBUG(dbgs() << "LV: Too many memory checks needed.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Too many memory checks needed.\n"
; } } while (false)
;
2287 Failed = true;
2288 }
2289
2290 return Failed;
2291 }
2292
2293private:
2294 unsigned NumRuntimePointerChecks = 0;
2295 Instruction *UnsafeAlgebraInst = nullptr;
2296
2297 /// Interface to emit optimization remarks.
2298 OptimizationRemarkEmitter &ORE;
2299};
2300
2301} // end anonymous namespace
2302
2303static void addAcyclicInnerLoop(Loop &L, SmallVectorImpl<Loop *> &V) {
2304 if (L.empty()) {
2305 if (!hasCyclesInLoopBody(L))
2306 V.push_back(&L);
2307 return;
2308 }
2309 for (Loop *InnerL : L)
2310 addAcyclicInnerLoop(*InnerL, V);
2311}
2312
2313namespace {
2314
2315/// The LoopVectorize Pass.
2316struct LoopVectorize : public FunctionPass {
2317 /// Pass identification, replacement for typeid
2318 static char ID;
2319
2320 LoopVectorizePass Impl;
2321
2322 explicit LoopVectorize(bool NoUnrolling = false, bool AlwaysVectorize = true)
2323 : FunctionPass(ID) {
2324 Impl.DisableUnrolling = NoUnrolling;
2325 Impl.AlwaysVectorize = AlwaysVectorize;
2326 initializeLoopVectorizePass(*PassRegistry::getPassRegistry());
2327 }
2328
2329 bool runOnFunction(Function &F) override {
2330 if (skipFunction(F))
2331 return false;
2332
2333 auto *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
2334 auto *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
2335 auto *TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
2336 auto *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
2337 auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
2338 auto *TLIP = getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
2339 auto *TLI = TLIP ? &TLIP->getTLI() : nullptr;
2340 auto *AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
2341 auto *AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
2342 auto *LAA = &getAnalysis<LoopAccessLegacyAnalysis>();
2343 auto *DB = &getAnalysis<DemandedBitsWrapperPass>().getDemandedBits();
2344 auto *ORE = &getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE();
2345
2346 std::function<const LoopAccessInfo &(Loop &)> GetLAA =
2347 [&](Loop &L) -> const LoopAccessInfo & { return LAA->getInfo(&L); };
2348
2349 return Impl.runImpl(F, *SE, *LI, *TTI, *DT, *BFI, TLI, *DB, *AA, *AC,
2350 GetLAA, *ORE);
2351 }
2352
2353 void getAnalysisUsage(AnalysisUsage &AU) const override {
2354 AU.addRequired<AssumptionCacheTracker>();
2355 AU.addRequired<BlockFrequencyInfoWrapperPass>();
2356 AU.addRequired<DominatorTreeWrapperPass>();
2357 AU.addRequired<LoopInfoWrapperPass>();
2358 AU.addRequired<ScalarEvolutionWrapperPass>();
2359 AU.addRequired<TargetTransformInfoWrapperPass>();
2360 AU.addRequired<AAResultsWrapperPass>();
2361 AU.addRequired<LoopAccessLegacyAnalysis>();
2362 AU.addRequired<DemandedBitsWrapperPass>();
2363 AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
2364 AU.addPreserved<LoopInfoWrapperPass>();
2365 AU.addPreserved<DominatorTreeWrapperPass>();
2366 AU.addPreserved<BasicAAWrapperPass>();
2367 AU.addPreserved<GlobalsAAWrapperPass>();
2368 }
2369};
2370
2371} // end anonymous namespace
2372
2373//===----------------------------------------------------------------------===//
2374// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and
2375// LoopVectorizationCostModel and LoopVectorizationPlanner.
2376//===----------------------------------------------------------------------===//
2377
2378Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) {
2379 // We need to place the broadcast of invariant variables outside the loop.
2380 Instruction *Instr = dyn_cast<Instruction>(V);
2381 bool NewInstr = (Instr && Instr->getParent() == LoopVectorBody);
2382 bool Invariant = OrigLoop->isLoopInvariant(V) && !NewInstr;
2383
2384 // Place the code for broadcasting invariant variables in the new preheader.
2385 IRBuilder<>::InsertPointGuard Guard(Builder);
2386 if (Invariant)
2387 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
2388
2389 // Broadcast the scalar into all locations in the vector.
2390 Value *Shuf = Builder.CreateVectorSplat(VF, V, "broadcast");
2391
2392 return Shuf;
2393}
2394
2395void InnerLoopVectorizer::createVectorIntOrFpInductionPHI(
2396 const InductionDescriptor &II, Value *Step, Instruction *EntryVal) {
2397 Value *Start = II.getStartValue();
2398
2399 // Construct the initial value of the vector IV in the vector loop preheader
2400 auto CurrIP = Builder.saveIP();
2401 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
2402 if (isa<TruncInst>(EntryVal)) {
2403 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2404, __extension__ __PRETTY_FUNCTION__))
2404 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2404, __extension__ __PRETTY_FUNCTION__))
;
2405 auto *TruncType = cast<IntegerType>(EntryVal->getType());
2406 Step = Builder.CreateTrunc(Step, TruncType);
2407 Start = Builder.CreateCast(Instruction::Trunc, Start, TruncType);
2408 }
2409 Value *SplatStart = Builder.CreateVectorSplat(VF, Start);
2410 Value *SteppedStart =
2411 getStepVector(SplatStart, 0, Step, II.getInductionOpcode());
2412
2413 // We create vector phi nodes for both integer and floating-point induction
2414 // variables. Here, we determine the kind of arithmetic we will perform.
2415 Instruction::BinaryOps AddOp;
2416 Instruction::BinaryOps MulOp;
2417 if (Step->getType()->isIntegerTy()) {
2418 AddOp = Instruction::Add;
2419 MulOp = Instruction::Mul;
2420 } else {
2421 AddOp = II.getInductionOpcode();
2422 MulOp = Instruction::FMul;
2423 }
2424
2425 // Multiply the vectorization factor by the step using integer or
2426 // floating-point arithmetic as appropriate.
2427 Value *ConstVF = getSignedIntOrFpConstant(Step->getType(), VF);
2428 Value *Mul = addFastMathFlag(Builder.CreateBinOp(MulOp, Step, ConstVF));
2429
2430 // Create a vector splat to use in the induction update.
2431 //
2432 // FIXME: If the step is non-constant, we create the vector splat with
2433 // IRBuilder. IRBuilder can constant-fold the multiply, but it doesn't
2434 // handle a constant vector splat.
2435 Value *SplatVF = isa<Constant>(Mul)
2436 ? ConstantVector::getSplat(VF, cast<Constant>(Mul))
2437 : Builder.CreateVectorSplat(VF, Mul);
2438 Builder.restoreIP(CurrIP);
2439
2440 // We may need to add the step a number of times, depending on the unroll
2441 // factor. The last of those goes into the PHI.
2442 PHINode *VecInd = PHINode::Create(SteppedStart->getType(), 2, "vec.ind",
2443 &*LoopVectorBody->getFirstInsertionPt());
2444 Instruction *LastInduction = VecInd;
2445 for (unsigned Part = 0; Part < UF; ++Part) {
2446 VectorLoopValueMap.setVectorValue(EntryVal, Part, LastInduction);
2447
2448 if (isa<TruncInst>(EntryVal))
2449 addMetadata(LastInduction, EntryVal);
2450 else
2451 recordVectorLoopValueForInductionCast(II, LastInduction, Part);
2452
2453 LastInduction = cast<Instruction>(addFastMathFlag(
2454 Builder.CreateBinOp(AddOp, LastInduction, SplatVF, "step.add")));
2455 }
2456
2457 // Move the last step to the end of the latch block. This ensures consistent
2458 // placement of all induction updates.
2459 auto *LoopVectorLatch = LI->getLoopFor(LoopVectorBody)->getLoopLatch();
2460 auto *Br = cast<BranchInst>(LoopVectorLatch->getTerminator());
2461 auto *ICmp = cast<Instruction>(Br->getCondition());
2462 LastInduction->moveBefore(ICmp);
2463 LastInduction->setName("vec.ind.next");
2464
2465 VecInd->addIncoming(SteppedStart, LoopVectorPreHeader);
2466 VecInd->addIncoming(LastInduction, LoopVectorLatch);
2467}
2468
2469bool InnerLoopVectorizer::shouldScalarizeInstruction(Instruction *I) const {
2470 return Cost->isScalarAfterVectorization(I, VF) ||
2471 Cost->isProfitableToScalarize(I, VF);
2472}
2473
2474bool InnerLoopVectorizer::needsScalarInduction(Instruction *IV) const {
2475 if (shouldScalarizeInstruction(IV))
2476 return true;
2477 auto isScalarInst = [&](User *U) -> bool {
2478 auto *I = cast<Instruction>(U);
2479 return (OrigLoop->contains(I) && shouldScalarizeInstruction(I));
2480 };
2481 return llvm::any_of(IV->users(), isScalarInst);
2482}
2483
2484void InnerLoopVectorizer::recordVectorLoopValueForInductionCast(
2485 const InductionDescriptor &ID, Value *VectorLoopVal, unsigned Part,
2486 unsigned Lane) {
2487 const SmallVectorImpl<Instruction *> &Casts = ID.getCastInsts();
2488 if (Casts.empty())
2489 return;
2490 // Only the first Cast instruction in the Casts vector is of interest.
2491 // The rest of the Casts (if exist) have no uses outside the
2492 // induction update chain itself.
2493 Instruction *CastInst = *Casts.begin();
2494 if (Lane < UINT_MAX(2147483647 *2U +1U))
2495 VectorLoopValueMap.setScalarValue(CastInst, {Part, Lane}, VectorLoopVal);
2496 else
2497 VectorLoopValueMap.setVectorValue(CastInst, Part, VectorLoopVal);
2498}
2499
2500void InnerLoopVectorizer::widenIntOrFpInduction(PHINode *IV, TruncInst *Trunc) {
2501 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2502, __extension__ __PRETTY_FUNCTION__))
2502 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2502, __extension__ __PRETTY_FUNCTION__))
;
2503
2504 auto II = Legal->getInductionVars()->find(IV);
2505 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2505, __extension__ __PRETTY_FUNCTION__))
;
2506
2507 auto ID = II->second;
2508 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2508, __extension__ __PRETTY_FUNCTION__))
;
2509
2510 // The scalar value to broadcast. This will be derived from the canonical
2511 // induction variable.
2512 Value *ScalarIV = nullptr;
2513
2514 // The value from the original loop to which we are mapping the new induction
2515 // variable.
2516 Instruction *EntryVal = Trunc ? cast<Instruction>(Trunc) : IV;
2517
2518 // True if we have vectorized the induction variable.
2519 auto VectorizedIV = false;
2520
2521 // Determine if we want a scalar version of the induction variable. This is
2522 // true if the induction variable itself is not widened, or if it has at
2523 // least one user in the loop that is not widened.
2524 auto NeedsScalarIV = VF > 1 && needsScalarInduction(EntryVal);
2525
2526 // Generate code for the induction step. Note that induction steps are
2527 // required to be loop-invariant
2528 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2529, __extension__ __PRETTY_FUNCTION__))
2529 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2529, __extension__ __PRETTY_FUNCTION__))
;
2530 auto &DL = OrigLoop->getHeader()->getModule()->getDataLayout();
2531 Value *Step = nullptr;
2532 if (PSE.getSE()->isSCEVable(IV->getType())) {
2533 SCEVExpander Exp(*PSE.getSE(), DL, "induction");
2534 Step = Exp.expandCodeFor(ID.getStep(), ID.getStep()->getType(),
2535 LoopVectorPreHeader->getTerminator());
2536 } else {
2537 Step = cast<SCEVUnknown>(ID.getStep())->getValue();
2538 }
2539
2540 // Try to create a new independent vector induction variable. If we can't
2541 // create the phi node, we will splat the scalar induction variable in each
2542 // loop iteration.
2543 if (VF > 1 && !shouldScalarizeInstruction(EntryVal)) {
2544 createVectorIntOrFpInductionPHI(ID, Step, EntryVal);
2545 VectorizedIV = true;
2546 }
2547
2548 // If we haven't yet vectorized the induction variable, or if we will create
2549 // a scalar one, we need to define the scalar induction variable and step
2550 // values. If we were given a truncation type, truncate the canonical
2551 // induction variable and step. Otherwise, derive these values from the
2552 // induction descriptor.
2553 if (!VectorizedIV || NeedsScalarIV) {
2554 ScalarIV = Induction;
2555 if (IV != OldInduction) {
2556 ScalarIV = IV->getType()->isIntegerTy()
2557 ? Builder.CreateSExtOrTrunc(Induction, IV->getType())
2558 : Builder.CreateCast(Instruction::SIToFP, Induction,
2559 IV->getType());
2560 ScalarIV = ID.transform(Builder, ScalarIV, PSE.getSE(), DL);
2561 ScalarIV->setName("offset.idx");
2562 }
2563 if (Trunc) {
2564 auto *TruncType = cast<IntegerType>(Trunc->getType());
2565 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2566, __extension__ __PRETTY_FUNCTION__))
2566 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2566, __extension__ __PRETTY_FUNCTION__))
;
2567 ScalarIV = Builder.CreateTrunc(ScalarIV, TruncType);
2568 Step = Builder.CreateTrunc(Step, TruncType);
2569 }
2570 }
2571
2572 // If we haven't yet vectorized the induction variable, splat the scalar
2573 // induction variable, and build the necessary step vectors.
2574 // TODO: Don't do it unless the vectorized IV is really required.
2575 if (!VectorizedIV) {
2576 Value *Broadcasted = getBroadcastInstrs(ScalarIV);
2577 for (unsigned Part = 0; Part < UF; ++Part) {
2578 Value *EntryPart =
2579 getStepVector(Broadcasted, VF * Part, Step, ID.getInductionOpcode());
2580 VectorLoopValueMap.setVectorValue(EntryVal, Part, EntryPart);
2581 if (Trunc)
2582 addMetadata(EntryPart, Trunc);
2583 else
2584 recordVectorLoopValueForInductionCast(ID, EntryPart, Part);
2585 }
2586 }
2587
2588 // If an induction variable is only used for counting loop iterations or
2589 // calculating addresses, it doesn't need to be widened. Create scalar steps
2590 // that can be used by instructions we will later scalarize. Note that the
2591 // addition of the scalar steps will not increase the number of instructions
2592 // in the loop in the common case prior to InstCombine. We will be trading
2593 // one vector extract for each scalar step.
2594 if (NeedsScalarIV)
2595 buildScalarSteps(ScalarIV, Step, EntryVal, ID);
2596}
2597
2598Value *InnerLoopVectorizer::getStepVector(Value *Val, int StartIdx, Value *Step,
2599 Instruction::BinaryOps BinOp) {
2600 // Create and check the types.
2601 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2601, __extension__ __PRETTY_FUNCTION__))
;
2602 int VLen = Val->getType()->getVectorNumElements();
2603
2604 Type *STy = Val->getType()->getScalarType();
2605 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2606, __extension__ __PRETTY_FUNCTION__))
2606 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2606, __extension__ __PRETTY_FUNCTION__))
;
2607 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2607, __extension__ __PRETTY_FUNCTION__))
;
2608
2609 SmallVector<Constant *, 8> Indices;
2610
2611 if (STy->isIntegerTy()) {
2612 // Create a vector of consecutive numbers from zero to VF.
2613 for (int i = 0; i < VLen; ++i)
2614 Indices.push_back(ConstantInt::get(STy, StartIdx + i));
2615
2616 // Add the consecutive indices to the vector value.
2617 Constant *Cv = ConstantVector::get(Indices);
2618 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2618, __extension__ __PRETTY_FUNCTION__))
;
2619 Step = Builder.CreateVectorSplat(VLen, Step);
2620 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2620, __extension__ __PRETTY_FUNCTION__))
;
2621 // FIXME: The newly created binary instructions should contain nsw/nuw flags,
2622 // which can be found from the original scalar operations.
2623 Step = Builder.CreateMul(Cv, Step);
2624 return Builder.CreateAdd(Val, Step, "induction");
2625 }
2626
2627 // Floating point induction.
2628 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2629, __extension__ __PRETTY_FUNCTION__))
2629 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2629, __extension__ __PRETTY_FUNCTION__))
;
2630 // Create a vector of consecutive numbers from zero to VF.
2631 for (int i = 0; i < VLen; ++i)
2632 Indices.push_back(ConstantFP::get(STy, (double)(StartIdx + i)));
2633
2634 // Add the consecutive indices to the vector value.
2635 Constant *Cv = ConstantVector::get(Indices);
2636
2637 Step = Builder.CreateVectorSplat(VLen, Step);
2638
2639 // Floating point operations had to be 'fast' to enable the induction.
2640 FastMathFlags Flags;
2641 Flags.setFast();
2642
2643 Value *MulOp = Builder.CreateFMul(Cv, Step);
2644 if (isa<Instruction>(MulOp))
2645 // Have to check, MulOp may be a constant
2646 cast<Instruction>(MulOp)->setFastMathFlags(Flags);
2647
2648 Value *BOp = Builder.CreateBinOp(BinOp, Val, MulOp, "induction");
2649 if (isa<Instruction>(BOp))
2650 cast<Instruction>(BOp)->setFastMathFlags(Flags);
2651 return BOp;
2652}
2653
2654void InnerLoopVectorizer::buildScalarSteps(Value *ScalarIV, Value *Step,
2655 Value *EntryVal,
2656 const InductionDescriptor &ID) {
2657 // We shouldn't have to build scalar steps if we aren't vectorizing.
2658 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2658, __extension__ __PRETTY_FUNCTION__))
;
2659
2660 // Get the value type and ensure it and the step have the same integer type.
2661 Type *ScalarIVTy = ScalarIV->getType()->getScalarType();
2662 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2663, __extension__ __PRETTY_FUNCTION__))
2663 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2663, __extension__ __PRETTY_FUNCTION__))
;
2664
2665 // We build scalar steps for both integer and floating-point induction
2666 // variables. Here, we determine the kind of arithmetic we will perform.
2667 Instruction::BinaryOps AddOp;
2668 Instruction::BinaryOps MulOp;
2669 if (ScalarIVTy->isIntegerTy()) {
2670 AddOp = Instruction::Add;
2671 MulOp = Instruction::Mul;
2672 } else {
2673 AddOp = ID.getInductionOpcode();
2674 MulOp = Instruction::FMul;
2675 }
2676
2677 // Determine the number of scalars we need to generate for each unroll
2678 // iteration. If EntryVal is uniform, we only need to generate the first
2679 // lane. Otherwise, we generate all VF values.
2680 unsigned Lanes =
2681 Cost->isUniformAfterVectorization(cast<Instruction>(EntryVal), VF) ? 1
2682 : VF;
2683 // Compute the scalar steps and save the results in VectorLoopValueMap.
2684 for (unsigned Part = 0; Part < UF; ++Part) {
2685 for (unsigned Lane = 0; Lane < Lanes; ++Lane) {
2686 auto *StartIdx = getSignedIntOrFpConstant(ScalarIVTy, VF * Part + Lane);
2687 auto *Mul = addFastMathFlag(Builder.CreateBinOp(MulOp, StartIdx, Step));
2688 auto *Add = addFastMathFlag(Builder.CreateBinOp(AddOp, ScalarIV, Mul));
2689 VectorLoopValueMap.setScalarValue(EntryVal, {Part, Lane}, Add);
2690 recordVectorLoopValueForInductionCast(ID, Add, Part, Lane);
2691 }
2692 }
2693}
2694
2695int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
2696 const ValueToValueMap &Strides = getSymbolicStrides() ? *getSymbolicStrides() :
2697 ValueToValueMap();
2698
2699 int Stride = getPtrStride(PSE, Ptr, TheLoop, Strides, true, false);
2700 if (Stride == 1 || Stride == -1)
2701 return Stride;
2702 return 0;
2703}
2704
2705bool LoopVectorizationLegality::isUniform(Value *V) {
2706 return LAI->isUniform(V);
2707}
2708
2709Value *InnerLoopVectorizer::getOrCreateVectorValue(Value *V, unsigned Part) {
2710 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2710, __extension__ __PRETTY_FUNCTION__))
;
2711 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2711, __extension__ __PRETTY_FUNCTION__))
;
2712 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2712, __extension__ __PRETTY_FUNCTION__))
;
2713
2714 // If we have a stride that is replaced by one, do it here.
2715 if (Legal->hasStride(V))
2716 V = ConstantInt::get(V->getType(), 1);
2717
2718 // If we have a vector mapped to this value, return it.
2719 if (VectorLoopValueMap.hasVectorValue(V, Part))
2720 return VectorLoopValueMap.getVectorValue(V, Part);
2721
2722 // If the value has not been vectorized, check if it has been scalarized
2723 // instead. If it has been scalarized, and we actually need the value in
2724 // vector form, we will construct the vector values on demand.
2725 if (VectorLoopValueMap.hasAnyScalarValue(V)) {
2726 Value *ScalarValue = VectorLoopValueMap.getScalarValue(V, {Part, 0});
2727
2728 // If we've scalarized a value, that value should be an instruction.
2729 auto *I = cast<Instruction>(V);
2730
2731 // If we aren't vectorizing, we can just copy the scalar map values over to
2732 // the vector map.
2733 if (VF == 1) {
2734 VectorLoopValueMap.setVectorValue(V, Part, ScalarValue);
2735 return ScalarValue;
2736 }
2737
2738 // Get the last scalar instruction we generated for V and Part. If the value
2739 // is known to be uniform after vectorization, this corresponds to lane zero
2740 // of the Part unroll iteration. Otherwise, the last instruction is the one
2741 // we created for the last vector lane of the Part unroll iteration.
2742 unsigned LastLane = Cost->isUniformAfterVectorization(I, VF) ? 0 : VF - 1;
2743 auto *LastInst = cast<Instruction>(
2744 VectorLoopValueMap.getScalarValue(V, {Part, LastLane}));
2745
2746 // Set the insert point after the last scalarized instruction. This ensures
2747 // the insertelement sequence will directly follow the scalar definitions.
2748 auto OldIP = Builder.saveIP();
2749 auto NewIP = std::next(BasicBlock::iterator(LastInst));
2750 Builder.SetInsertPoint(&*NewIP);
2751
2752 // However, if we are vectorizing, we need to construct the vector values.
2753 // If the value is known to be uniform after vectorization, we can just
2754 // broadcast the scalar value corresponding to lane zero for each unroll
2755 // iteration. Otherwise, we construct the vector values using insertelement
2756 // instructions. Since the resulting vectors are stored in
2757 // VectorLoopValueMap, we will only generate the insertelements once.
2758 Value *VectorValue = nullptr;
2759 if (Cost->isUniformAfterVectorization(I, VF)) {
2760 VectorValue = getBroadcastInstrs(ScalarValue);
2761 VectorLoopValueMap.setVectorValue(V, Part, VectorValue);
2762 } else {
2763 // Initialize packing with insertelements to start from undef.
2764 Value *Undef = UndefValue::get(VectorType::get(V->getType(), VF));
2765 VectorLoopValueMap.setVectorValue(V, Part, Undef);
2766 for (unsigned Lane = 0; Lane < VF; ++Lane)
2767 packScalarIntoVectorValue(V, {Part, Lane});
2768 VectorValue = VectorLoopValueMap.getVectorValue(V, Part);
2769 }
2770 Builder.restoreIP(OldIP);
2771 return VectorValue;
2772 }
2773
2774 // If this scalar is unknown, assume that it is a constant or that it is
2775 // loop invariant. Broadcast V and save the value for future uses.
2776 Value *B = getBroadcastInstrs(V);
2777 VectorLoopValueMap.setVectorValue(V, Part, B);
2778 return B;
2779}
2780
2781Value *
2782InnerLoopVectorizer::getOrCreateScalarValue(Value *V,
2783 const VPIteration &Instance) {
2784 // If the value is not an instruction contained in the loop, it should
2785 // already be scalar.
2786 if (OrigLoop->isLoopInvariant(V))
2787 return V;
2788
2789 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2791, __extension__ __PRETTY_FUNCTION__))
2790 ? !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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2791, __extension__ __PRETTY_FUNCTION__))
2791 : 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2791, __extension__ __PRETTY_FUNCTION__))
;
2792
2793 // If the value from the original loop has not been vectorized, it is
2794 // represented by UF x VF scalar values in the new loop. Return the requested
2795 // scalar value.
2796 if (VectorLoopValueMap.hasScalarValue(V, Instance))
2797 return VectorLoopValueMap.getScalarValue(V, Instance);
2798
2799 // If the value has not been scalarized, get its entry in VectorLoopValueMap
2800 // for the given unroll part. If this entry is not a vector type (i.e., the
2801 // vectorization factor is one), there is no need to generate an
2802 // extractelement instruction.
2803 auto *U = getOrCreateVectorValue(V, Instance.Part);
2804 if (!U->getType()->isVectorTy()) {
2805 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2805, __extension__ __PRETTY_FUNCTION__))
;
2806 return U;
2807 }
2808
2809 // Otherwise, the value from the original loop has been vectorized and is
2810 // represented by UF vector values. Extract and return the requested scalar
2811 // value from the appropriate vector lane.
2812 return Builder.CreateExtractElement(U, Builder.getInt32(Instance.Lane));
2813}
2814
2815void InnerLoopVectorizer::packScalarIntoVectorValue(
2816 Value *V, const VPIteration &Instance) {
2817 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2817, __extension__ __PRETTY_FUNCTION__))
;
2818 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2818, __extension__ __PRETTY_FUNCTION__))
;
2819 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2819, __extension__ __PRETTY_FUNCTION__))
;
2820
2821 Value *ScalarInst = VectorLoopValueMap.getScalarValue(V, Instance);
2822 Value *VectorValue = VectorLoopValueMap.getVectorValue(V, Instance.Part);
2823 VectorValue = Builder.CreateInsertElement(VectorValue, ScalarInst,
2824 Builder.getInt32(Instance.Lane));
2825 VectorLoopValueMap.resetVectorValue(V, Instance.Part, VectorValue);
2826}
2827
2828Value *InnerLoopVectorizer::reverseVector(Value *Vec) {
2829 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2829, __extension__ __PRETTY_FUNCTION__))
;
2830 SmallVector<Constant *, 8> ShuffleMask;
2831 for (unsigned i = 0; i < VF; ++i)
2832 ShuffleMask.push_back(Builder.getInt32(VF - i - 1));
2833
2834 return Builder.CreateShuffleVector(Vec, UndefValue::get(Vec->getType()),
2835 ConstantVector::get(ShuffleMask),
2836 "reverse");
2837}
2838
2839// Try to vectorize the interleave group that \p Instr belongs to.
2840//
2841// E.g. Translate following interleaved load group (factor = 3):
2842// for (i = 0; i < N; i+=3) {
2843// R = Pic[i]; // Member of index 0
2844// G = Pic[i+1]; // Member of index 1
2845// B = Pic[i+2]; // Member of index 2
2846// ... // do something to R, G, B
2847// }
2848// To:
2849// %wide.vec = load <12 x i32> ; Read 4 tuples of R,G,B
2850// %R.vec = shuffle %wide.vec, undef, <0, 3, 6, 9> ; R elements
2851// %G.vec = shuffle %wide.vec, undef, <1, 4, 7, 10> ; G elements
2852// %B.vec = shuffle %wide.vec, undef, <2, 5, 8, 11> ; B elements
2853//
2854// Or translate following interleaved store group (factor = 3):
2855// for (i = 0; i < N; i+=3) {
2856// ... do something to R, G, B
2857// Pic[i] = R; // Member of index 0
2858// Pic[i+1] = G; // Member of index 1
2859// Pic[i+2] = B; // Member of index 2
2860// }
2861// To:
2862// %R_G.vec = shuffle %R.vec, %G.vec, <0, 1, 2, ..., 7>
2863// %B_U.vec = shuffle %B.vec, undef, <0, 1, 2, 3, u, u, u, u>
2864// %interleaved.vec = shuffle %R_G.vec, %B_U.vec,
2865// <0, 4, 8, 1, 5, 9, 2, 6, 10, 3, 7, 11> ; Interleave R,G,B elements
2866// store <12 x i32> %interleaved.vec ; Write 4 tuples of R,G,B
2867void InnerLoopVectorizer::vectorizeInterleaveGroup(Instruction *Instr) {
2868 const InterleaveGroup *Group = Legal->getInterleavedAccessGroup(Instr);
2869 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2869, __extension__ __PRETTY_FUNCTION__))
;
2870
2871 // Skip if current instruction is not the insert position.
2872 if (Instr != Group->getInsertPos())
2873 return;
2874
2875 const DataLayout &DL = Instr->getModule()->getDataLayout();
2876 Value *Ptr = getPointerOperand(Instr);
2877
2878 // Prepare for the vector type of the interleaved load/store.
2879 Type *ScalarTy = getMemInstValueType(Instr);
2880 unsigned InterleaveFactor = Group->getFactor();
2881 Type *VecTy = VectorType::get(ScalarTy, InterleaveFactor * VF);
2882 Type *PtrTy = VecTy->getPointerTo(getMemInstAddressSpace(Instr));
2883
2884 // Prepare for the new pointers.
2885 setDebugLocFromInst(Builder, Ptr);
2886 SmallVector<Value *, 2> NewPtrs;
2887 unsigned Index = Group->getIndex(Instr);
2888
2889 // If the group is reverse, adjust the index to refer to the last vector lane
2890 // instead of the first. We adjust the index from the first vector lane,
2891 // rather than directly getting the pointer for lane VF - 1, because the
2892 // pointer operand of the interleaved access is supposed to be uniform. For
2893 // uniform instructions, we're only required to generate a value for the
2894 // first vector lane in each unroll iteration.
2895 if (Group->isReverse())
2896 Index += (VF - 1) * Group->getFactor();
2897
2898 for (unsigned Part = 0; Part < UF; Part++) {
2899 Value *NewPtr = getOrCreateScalarValue(Ptr, {Part, 0});
2900
2901 // Notice current instruction could be any index. Need to adjust the address
2902 // to the member of index 0.
2903 //
2904 // E.g. a = A[i+1]; // Member of index 1 (Current instruction)
2905 // b = A[i]; // Member of index 0
2906 // Current pointer is pointed to A[i+1], adjust it to A[i].
2907 //
2908 // E.g. A[i+1] = a; // Member of index 1
2909 // A[i] = b; // Member of index 0
2910 // A[i+2] = c; // Member of index 2 (Current instruction)
2911 // Current pointer is pointed to A[i+2], adjust it to A[i].
2912 NewPtr = Builder.CreateGEP(NewPtr, Builder.getInt32(-Index));
2913
2914 // Cast to the vector pointer type.
2915 NewPtrs.push_back(Builder.CreateBitCast(NewPtr, PtrTy));
2916 }
2917
2918 setDebugLocFromInst(Builder, Instr);
2919 Value *UndefVec = UndefValue::get(VecTy);
2920
2921 // Vectorize the interleaved load group.
2922 if (isa<LoadInst>(Instr)) {
2923 // For each unroll part, create a wide load for the group.
2924 SmallVector<Value *, 2> NewLoads;
2925 for (unsigned Part = 0; Part < UF; Part++) {
2926 auto *NewLoad = Builder.CreateAlignedLoad(
2927 NewPtrs[Part], Group->getAlignment(), "wide.vec");
2928 Group->addMetadata(NewLoad);
2929 NewLoads.push_back(NewLoad);
2930 }
2931
2932 // For each member in the group, shuffle out the appropriate data from the
2933 // wide loads.
2934 for (unsigned I = 0; I < InterleaveFactor; ++I) {
2935 Instruction *Member = Group->getMember(I);
2936
2937 // Skip the gaps in the group.
2938 if (!Member)
2939 continue;
2940
2941 Constant *StrideMask = createStrideMask(Builder, I, InterleaveFactor, VF);
2942 for (unsigned Part = 0; Part < UF; Part++) {
2943 Value *StridedVec = Builder.CreateShuffleVector(
2944 NewLoads[Part], UndefVec, StrideMask, "strided.vec");
2945
2946 // If this member has different type, cast the result type.
2947 if (Member->getType() != ScalarTy) {
2948 VectorType *OtherVTy = VectorType::get(Member->getType(), VF);
2949 StridedVec = createBitOrPointerCast(StridedVec, OtherVTy, DL);
2950 }
2951
2952 if (Group->isReverse())
2953 StridedVec = reverseVector(StridedVec);
2954
2955 VectorLoopValueMap.setVectorValue(Member, Part, StridedVec);
2956 }
2957 }
2958 return;
2959 }
2960
2961 // The sub vector type for current instruction.
2962 VectorType *SubVT = VectorType::get(ScalarTy, VF);
2963
2964 // Vectorize the interleaved store group.
2965 for (unsigned Part = 0; Part < UF; Part++) {
2966 // Collect the stored vector from each member.
2967 SmallVector<Value *, 4> StoredVecs;
2968 for (unsigned i = 0; i < InterleaveFactor; i++) {
2969 // Interleaved store group doesn't allow a gap, so each index has a member
2970 Instruction *Member = Group->getMember(i);
2971 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 2971, __extension__ __PRETTY_FUNCTION__))
;
2972
2973 Value *StoredVec = getOrCreateVectorValue(
2974 cast<StoreInst>(Member)->getValueOperand(), Part);
2975 if (Group->isReverse())
2976 StoredVec = reverseVector(StoredVec);
2977
2978 // If this member has different type, cast it to a unified type.
2979
2980 if (StoredVec->getType() != SubVT)
2981 StoredVec = createBitOrPointerCast(StoredVec, SubVT, DL);
2982
2983 StoredVecs.push_back(StoredVec);
2984 }
2985
2986 // Concatenate all vectors into a wide vector.
2987 Value *WideVec = concatenateVectors(Builder, StoredVecs);
2988
2989 // Interleave the elements in the wide vector.
2990 Constant *IMask = createInterleaveMask(Builder, VF, InterleaveFactor);
2991 Value *IVec = Builder.CreateShuffleVector(WideVec, UndefVec, IMask,
2992 "interleaved.vec");
2993
2994 Instruction *NewStoreInstr =
2995 Builder.CreateAlignedStore(IVec, NewPtrs[Part], Group->getAlignment());
2996
2997 Group->addMetadata(NewStoreInstr);
2998 }
2999}
3000
3001void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr,
3002 VectorParts *BlockInMask) {
3003 // Attempt to issue a wide load.
3004 LoadInst *LI = dyn_cast<LoadInst>(Instr);
3005 StoreInst *SI = dyn_cast<StoreInst>(Instr);
3006
3007 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3007, __extension__ __PRETTY_FUNCTION__))
;
3008
3009 LoopVectorizationCostModel::InstWidening Decision =
3010 Cost->getWideningDecision(Instr, VF);
3011 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3012, __extension__ __PRETTY_FUNCTION__))
3012 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3012, __extension__ __PRETTY_FUNCTION__))
;
3013 if (Decision == LoopVectorizationCostModel::CM_Interleave)
3014 return vectorizeInterleaveGroup(Instr);
3015
3016 Type *ScalarDataTy = getMemInstValueType(Instr);
3017 Type *DataTy = VectorType::get(ScalarDataTy, VF);
3018 Value *Ptr = getPointerOperand(Instr);
3019 unsigned Alignment = getMemInstAlignment(Instr);
3020 // An alignment of 0 means target abi alignment. We need to use the scalar's
3021 // target abi alignment in such a case.
3022 const DataLayout &DL = Instr->getModule()->getDataLayout();
3023 if (!Alignment)
3024 Alignment = DL.getABITypeAlignment(ScalarDataTy);
3025 unsigned AddressSpace = getMemInstAddressSpace(Instr);
3026
3027 // Determine if the pointer operand of the access is either consecutive or
3028 // reverse consecutive.
3029 bool Reverse = (Decision == LoopVectorizationCostModel::CM_Widen_Reverse);
3030 bool ConsecutiveStride =
3031 Reverse || (Decision == LoopVectorizationCostModel::CM_Widen);
3032 bool CreateGatherScatter =
3033 (Decision == LoopVectorizationCostModel::CM_GatherScatter);
3034
3035 // Either Ptr feeds a vector load/store, or a vector GEP should feed a vector
3036 // gather/scatter. Otherwise Decision should have been to Scalarize.
3037 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3038, __extension__ __PRETTY_FUNCTION__))
3038 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3038, __extension__ __PRETTY_FUNCTION__))
;
3039
3040 // Handle consecutive loads/stores.
3041 if (ConsecutiveStride)
3042 Ptr = getOrCreateScalarValue(Ptr, {0, 0});
3043
3044 VectorParts Mask;
3045 bool isMaskRequired = BlockInMask;
3046 if (isMaskRequired)
3047 Mask = *BlockInMask;
3048
3049 // Handle Stores:
3050 if (SI) {
3051 assert(!Legal->isUniform(SI->getPointerOperand()) &&(static_cast <bool> (!Legal->isUniform(SI->getPointerOperand
()) && "We do not allow storing to uniform addresses"
) ? void (0) : __assert_fail ("!Legal->isUniform(SI->getPointerOperand()) && \"We do not allow storing to uniform addresses\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3052, __extension__ __PRETTY_FUNCTION__))
3052 "We do not allow storing to uniform addresses")(static_cast <bool> (!Legal->isUniform(SI->getPointerOperand
()) && "We do not allow storing to uniform addresses"
) ? void (0) : __assert_fail ("!Legal->isUniform(SI->getPointerOperand()) && \"We do not allow storing to uniform addresses\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3052, __extension__ __PRETTY_FUNCTION__))
;
3053 setDebugLocFromInst(Builder, SI);
3054
3055 for (unsigned Part = 0; Part < UF; ++Part) {
3056 Instruction *NewSI = nullptr;
3057 Value *StoredVal = getOrCreateVectorValue(SI->getValueOperand(), Part);
3058 if (CreateGatherScatter) {
3059 Value *MaskPart = isMaskRequired ? Mask[Part] : nullptr;
3060 Value *VectorGep = getOrCreateVectorValue(Ptr, Part);
3061 NewSI = Builder.CreateMaskedScatter(StoredVal, VectorGep, Alignment,
3062 MaskPart);
3063 } else {
3064 // Calculate the pointer for the specific unroll-part.
3065 Value *PartPtr =
3066 Builder.CreateGEP(nullptr, Ptr, Builder.getInt32(Part * VF));
3067
3068 if (Reverse) {
3069 // If we store to reverse consecutive memory locations, then we need
3070 // to reverse the order of elements in the stored value.
3071 StoredVal = reverseVector(StoredVal);
3072 // We don't want to update the value in the map as it might be used in
3073 // another expression. So don't call resetVectorValue(StoredVal).
3074
3075 // If the address is consecutive but reversed, then the
3076 // wide store needs to start at the last vector element.
3077 PartPtr =
3078 Builder.CreateGEP(nullptr, Ptr, Builder.getInt32(-Part * VF));
3079 PartPtr =
3080 Builder.CreateGEP(nullptr, PartPtr, Builder.getInt32(1 - VF));
3081 if (isMaskRequired) // Reverse of a null all-one mask is a null mask.
3082 Mask[Part] = reverseVector(Mask[Part]);
3083 }
3084
3085 Value *VecPtr =
3086 Builder.CreateBitCast(PartPtr, DataTy->getPointerTo(AddressSpace));
3087
3088 if (isMaskRequired)
3089 NewSI = Builder.CreateMaskedStore(StoredVal, VecPtr, Alignment,
3090 Mask[Part]);
3091 else
3092 NewSI = Builder.CreateAlignedStore(StoredVal, VecPtr, Alignment);
3093 }
3094 addMetadata(NewSI, SI);
3095 }
3096 return;
3097 }
3098
3099 // Handle loads.
3100 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3100, __extension__ __PRETTY_FUNCTION__))
;
3101 setDebugLocFromInst(Builder, LI);
3102 for (unsigned Part = 0; Part < UF; ++Part) {
3103 Value *NewLI;
3104 if (CreateGatherScatter) {
3105 Value *MaskPart = isMaskRequired ? Mask[Part] : nullptr;
3106 Value *VectorGep = getOrCreateVectorValue(Ptr, Part);
3107 NewLI = Builder.CreateMaskedGather(VectorGep, Alignment, MaskPart,
3108 nullptr, "wide.masked.gather");
3109 addMetadata(NewLI, LI);
3110 } else {
3111 // Calculate the pointer for the specific unroll-part.
3112 Value *PartPtr =
3113 Builder.CreateGEP(nullptr, Ptr, Builder.getInt32(Part * VF));
3114
3115 if (Reverse) {
3116 // If the address is consecutive but reversed, then the
3117 // wide load needs to start at the last vector element.
3118 PartPtr = Builder.CreateGEP(nullptr, Ptr, Builder.getInt32(-Part * VF));
3119 PartPtr = Builder.CreateGEP(nullptr, PartPtr, Builder.getInt32(1 - VF));
3120 if (isMaskRequired) // Reverse of a null all-one mask is a null mask.
3121 Mask[Part] = reverseVector(Mask[Part]);
3122 }
3123
3124 Value *VecPtr =
3125 Builder.CreateBitCast(PartPtr, DataTy->getPointerTo(AddressSpace));
3126 if (isMaskRequired)
3127 NewLI = Builder.CreateMaskedLoad(VecPtr, Alignment, Mask[Part],
3128 UndefValue::get(DataTy),
3129 "wide.masked.load");
3130 else
3131 NewLI = Builder.CreateAlignedLoad(VecPtr, Alignment, "wide.load");
3132
3133 // Add metadata to the load, but setVectorValue to the reverse shuffle.
3134 addMetadata(NewLI, LI);
3135 if (Reverse)
3136 NewLI = reverseVector(NewLI);
3137 }
3138 VectorLoopValueMap.setVectorValue(Instr, Part, NewLI);
3139 }
3140}
3141
3142void InnerLoopVectorizer::scalarizeInstruction(Instruction *Instr,
3143 const VPIteration &Instance,
3144 bool IfPredicateInstr) {
3145 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3145, __extension__ __PRETTY_FUNCTION__))
;
3146
3147 setDebugLocFromInst(Builder, Instr);
3148
3149 // Does this instruction return a value ?
3150 bool IsVoidRetTy = Instr->getType()->isVoidTy();
3151
3152 Instruction *Cloned = Instr->clone();
3153 if (!IsVoidRetTy)
3154 Cloned->setName(Instr->getName() + ".cloned");
3155
3156 // Replace the operands of the cloned instructions with their scalar
3157 // equivalents in the new loop.
3158 for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
3159 auto *NewOp = getOrCreateScalarValue(Instr->getOperand(op), Instance);
3160 Cloned->setOperand(op, NewOp);
3161 }
3162 addNewMetadata(Cloned, Instr);
3163
3164 // Place the cloned scalar in the new loop.
3165 Builder.Insert(Cloned);
3166
3167 // Add the cloned scalar to the scalar map entry.
3168 VectorLoopValueMap.setScalarValue(Instr, Instance, Cloned);
3169
3170 // If we just cloned a new assumption, add it the assumption cache.
3171 if (auto *II = dyn_cast<IntrinsicInst>(Cloned))
3172 if (II->getIntrinsicID() == Intrinsic::assume)
3173 AC->registerAssumption(II);
3174
3175 // End if-block.
3176 if (IfPredicateInstr)
3177 PredicatedInstructions.push_back(Cloned);
3178}
3179
3180PHINode *InnerLoopVectorizer::createInductionVariable(Loop *L, Value *Start,
3181 Value *End, Value *Step,
3182 Instruction *DL) {
3183 BasicBlock *Header = L->getHeader();
3184 BasicBlock *Latch = L->getLoopLatch();
3185 // As we're just creating this loop, it's possible no latch exists
3186 // yet. If so, use the header as this will be a single block loop.
3187 if (!Latch)
3188 Latch = Header;
3189
3190 IRBuilder<> Builder(&*Header->getFirstInsertionPt());
3191 Instruction *OldInst = getDebugLocFromInstOrOperands(OldInduction);
3192 setDebugLocFromInst(Builder, OldInst);
3193 auto *Induction = Builder.CreatePHI(Start->getType(), 2, "index");
3194
3195 Builder.SetInsertPoint(Latch->getTerminator());
3196 setDebugLocFromInst(Builder, OldInst);
3197
3198 // Create i+1 and fill the PHINode.
3199 Value *Next = Builder.CreateAdd(Induction, Step, "index.next");
3200 Induction->addIncoming(Start, L->getLoopPreheader());
3201 Induction->addIncoming(Next, Latch);
3202 // Create the compare.
3203 Value *ICmp = Builder.CreateICmpEQ(Next, End);
3204 Builder.CreateCondBr(ICmp, L->getExitBlock(), Header);
3205
3206 // Now we have two terminators. Remove the old one from the block.
3207 Latch->getTerminator()->eraseFromParent();
3208
3209 return Induction;
3210}
3211
3212Value *InnerLoopVectorizer::getOrCreateTripCount(Loop *L) {
3213 if (TripCount)
3214 return TripCount;
3215
3216 IRBuilder<> Builder(L->getLoopPreheader()->getTerminator());
3217 // Find the loop boundaries.
3218 ScalarEvolution *SE = PSE.getSE();
3219 const SCEV *BackedgeTakenCount = PSE.getBackedgeTakenCount();
3220 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3221, __extension__ __PRETTY_FUNCTION__))
3221 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3221, __extension__ __PRETTY_FUNCTION__))
;
3222
3223 Type *IdxTy = Legal->getWidestInductionType();
3224
3225 // The exit count might have the type of i64 while the phi is i32. This can
3226 // happen if we have an induction variable that is sign extended before the
3227 // compare. The only way that we get a backedge taken count is that the
3228 // induction variable was signed and as such will not overflow. In such a case
3229 // truncation is legal.
3230 if (BackedgeTakenCount->getType()->getPrimitiveSizeInBits() >
3231 IdxTy->getPrimitiveSizeInBits())
3232 BackedgeTakenCount = SE->getTruncateOrNoop(BackedgeTakenCount, IdxTy);
3233 BackedgeTakenCount = SE->getNoopOrZeroExtend(BackedgeTakenCount, IdxTy);
3234
3235 // Get the total trip count from the count by adding 1.
3236 const SCEV *ExitCount = SE->getAddExpr(
3237 BackedgeTakenCount, SE->getOne(BackedgeTakenCount->getType()));
3238
3239 const DataLayout &DL = L->getHeader()->getModule()->getDataLayout();
3240
3241 // Expand the trip count and place the new instructions in the preheader.
3242 // Notice that the pre-header does not change, only the loop body.
3243 SCEVExpander Exp(*SE, DL, "induction");
3244
3245 // Count holds the overall loop count (N).
3246 TripCount = Exp.expandCodeFor(ExitCount, ExitCount->getType(),
3247 L->getLoopPreheader()->getTerminator());
3248
3249 if (TripCount->getType()->isPointerTy())
3250 TripCount =
3251 CastInst::CreatePointerCast(TripCount, IdxTy, "exitcount.ptrcnt.to.int",
3252 L->getLoopPreheader()->getTerminator());
3253
3254 return TripCount;
3255}
3256
3257Value *InnerLoopVectorizer::getOrCreateVectorTripCount(Loop *L) {
3258 if (VectorTripCount)
3259 return VectorTripCount;
3260
3261 Value *TC = getOrCreateTripCount(L);
3262 IRBuilder<> Builder(L->getLoopPreheader()->getTerminator());
3263
3264 // Now we need to generate the expression for the part of the loop that the
3265 // vectorized body will execute. This is equal to N - (N % Step) if scalar
3266 // iterations are not required for correctness, or N - Step, otherwise. Step
3267 // is equal to the vectorization factor (number of SIMD elements) times the
3268 // unroll factor (number of SIMD instructions).
3269 Constant *Step = ConstantInt::get(TC->getType(), VF * UF);
3270 Value *R = Builder.CreateURem(TC, Step, "n.mod.vf");
3271
3272 // If there is a non-reversed interleaved group that may speculatively access
3273 // memory out-of-bounds, we need to ensure that there will be at least one
3274 // iteration of the scalar epilogue loop. Thus, if the step evenly divides
3275 // the trip count, we set the remainder to be equal to the step. If the step
3276 // does not evenly divide the trip count, no adjustment is necessary since
3277 // there will already be scalar iterations. Note that the minimum iterations
3278 // check ensures that N >= Step.
3279 if (VF > 1 && Legal->requiresScalarEpilogue()) {
3280 auto *IsZero = Builder.CreateICmpEQ(R, ConstantInt::get(R->getType(), 0));
3281 R = Builder.CreateSelect(IsZero, Step, R);
3282 }
3283
3284 VectorTripCount = Builder.CreateSub(TC, R, "n.vec");
3285
3286 return VectorTripCount;
3287}
3288
3289Value *InnerLoopVectorizer::createBitOrPointerCast(Value *V, VectorType *DstVTy,
3290 const DataLayout &DL) {
3291 // Verify that V is a vector type with same number of elements as DstVTy.
3292 unsigned VF = DstVTy->getNumElements();
3293 VectorType *SrcVecTy = cast<VectorType>(V->getType());
3294 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3294, __extension__ __PRETTY_FUNCTION__))
;
3295 Type *SrcElemTy = SrcVecTy->getElementType();
3296 Type *DstElemTy = DstVTy->getElementType();
3297 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3298, __extension__ __PRETTY_FUNCTION__))
3298 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3298, __extension__ __PRETTY_FUNCTION__))
;
3299
3300 // Do a direct cast if element types are castable.
3301 if (CastInst::isBitOrNoopPointerCastable(SrcElemTy, DstElemTy, DL)) {
3302 return Builder.CreateBitOrPointerCast(V, DstVTy);
3303 }
3304 // V cannot be directly casted to desired vector type.
3305 // May happen when V is a floating point vector but DstVTy is a vector of
3306 // pointers or vice-versa. Handle this using a two-step bitcast using an
3307 // intermediate Integer type for the bitcast i.e. Ptr <-> Int <-> Float.
3308 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3309, __extension__ __PRETTY_FUNCTION__))
3309 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3309, __extension__ __PRETTY_FUNCTION__))
;
3310 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3311, __extension__ __PRETTY_FUNCTION__))
3311 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3311, __extension__ __PRETTY_FUNCTION__))
;
3312 Type *IntTy =
3313 IntegerType::getIntNTy(V->getContext(), DL.getTypeSizeInBits(SrcElemTy));
3314 VectorType *VecIntTy = VectorType::get(IntTy, VF);
3315 Value *CastVal = Builder.CreateBitOrPointerCast(V, VecIntTy);
3316 return Builder.CreateBitOrPointerCast(CastVal, DstVTy);
3317}
3318
3319void InnerLoopVectorizer::emitMinimumIterationCountCheck(Loop *L,
3320 BasicBlock *Bypass) {
3321 Value *Count = getOrCreateTripCount(L);
3322 BasicBlock *BB = L->getLoopPreheader();
3323 IRBuilder<> Builder(BB->getTerminator());
3324
3325 // Generate code to check if the loop's trip count is less than VF * UF, or
3326 // equal to it in case a scalar epilogue is required; this implies that the
3327 // vector trip count is zero. This check also covers the case where adding one
3328 // to the backedge-taken count overflowed leading to an incorrect trip count
3329 // of zero. In this case we will also jump to the scalar loop.
3330 auto P = Legal->requiresScalarEpilogue() ? ICmpInst::ICMP_ULE
3331 : ICmpInst::ICMP_ULT;
3332 Value *CheckMinIters = Builder.CreateICmp(
3333 P, Count, ConstantInt::get(Count->getType(), VF * UF), "min.iters.check");
3334
3335 BasicBlock *NewBB = BB->splitBasicBlock(BB->getTerminator(), "vector.ph");
3336 // Update dominator tree immediately if the generated block is a
3337 // LoopBypassBlock because SCEV expansions to generate loop bypass
3338 // checks may query it before the current function is finished.
3339 DT->addNewBlock(NewBB, BB);
3340 if (L->getParentLoop())
3341 L->getParentLoop()->addBasicBlockToLoop(NewBB, *LI);
3342 ReplaceInstWithInst(BB->getTerminator(),
3343 BranchInst::Create(Bypass, NewBB, CheckMinIters));
3344 LoopBypassBlocks.push_back(BB);
3345}
3346
3347void InnerLoopVectorizer::emitSCEVChecks(Loop *L, BasicBlock *Bypass) {
3348 BasicBlock *BB = L->getLoopPreheader();
3349
3350 // Generate the code to check that the SCEV assumptions that we made.
3351 // We want the new basic block to start at the first instruction in a
3352 // sequence of instructions that form a check.
3353 SCEVExpander Exp(*PSE.getSE(), Bypass->getModule()->getDataLayout(),
3354 "scev.check");
3355 Value *SCEVCheck =
3356 Exp.expandCodeForPredicate(&PSE.getUnionPredicate(), BB->getTerminator());
3357
3358 if (auto *C = dyn_cast<ConstantInt>(SCEVCheck))
3359 if (C->isZero())
3360 return;
3361
3362 // Create a new block containing the stride check.
3363 BB->setName("vector.scevcheck");
3364 auto *NewBB = BB->splitBasicBlock(BB->getTerminator(), "vector.ph");
3365 // Update dominator tree immediately if the generated block is a
3366 // LoopBypassBlock because SCEV expansions to generate loop bypass
3367 // checks may query it before the current function is finished.
3368 DT->addNewBlock(NewBB, BB);
3369 if (L->getParentLoop())
3370 L->getParentLoop()->addBasicBlockToLoop(NewBB, *LI);
3371 ReplaceInstWithInst(BB->getTerminator(),
3372 BranchInst::Create(Bypass, NewBB, SCEVCheck));
3373 LoopBypassBlocks.push_back(BB);
3374 AddedSafetyChecks = true;
3375}
3376
3377void InnerLoopVectorizer::emitMemRuntimeChecks(Loop *L, BasicBlock *Bypass) {
3378 BasicBlock *BB = L->getLoopPreheader();
3379
3380 // Generate the code that checks in runtime if arrays overlap. We put the
3381 // checks into a separate block to make the more common case of few elements
3382 // faster.
3383 Instruction *FirstCheckInst;
3384 Instruction *MemRuntimeCheck;
3385 std::tie(FirstCheckInst, MemRuntimeCheck) =
3386 Legal->getLAI()->addRuntimeChecks(BB->getTerminator());
3387 if (!MemRuntimeCheck)
3388 return;
3389
3390 // Create a new block containing the memory check.
3391 BB->setName("vector.memcheck");
3392 auto *NewBB = BB->splitBasicBlock(BB->getTerminator(), "vector.ph");
3393 // Update dominator tree immediately if the generated block is a
3394 // LoopBypassBlock because SCEV expansions to generate loop bypass
3395 // checks may query it before the current function is finished.
3396 DT->addNewBlock(NewBB, BB);
3397 if (L->getParentLoop())
3398 L->getParentLoop()->addBasicBlockToLoop(NewBB, *LI);
3399 ReplaceInstWithInst(BB->getTerminator(),
3400 BranchInst::Create(Bypass, NewBB, MemRuntimeCheck));
3401 LoopBypassBlocks.push_back(BB);
3402 AddedSafetyChecks = true;
3403
3404 // We currently don't use LoopVersioning for the actual loop cloning but we
3405 // still use it to add the noalias metadata.
3406 LVer = llvm::make_unique<LoopVersioning>(*Legal->getLAI(), OrigLoop, LI, DT,
3407 PSE.getSE());
3408 LVer->prepareNoAliasMetadata();
3409}
3410
3411BasicBlock *InnerLoopVectorizer::createVectorizedLoopSkeleton() {
3412 /*
3413 In this function we generate a new loop. The new loop will contain
3414 the vectorized instructions while the old loop will continue to run the
3415 scalar remainder.
3416
3417 [ ] <-- loop iteration number check.
3418 / |
3419 / v
3420 | [ ] <-- vector loop bypass (may consist of multiple blocks).
3421 | / |
3422 | / v
3423 || [ ] <-- vector pre header.
3424 |/ |
3425 | v
3426 | [ ] \
3427 | [ ]_| <-- vector loop.
3428 | |
3429 | v
3430 | -[ ] <--- middle-block.
3431 | / |
3432 | / v
3433 -|- >[ ] <--- new preheader.
3434 | |
3435 | v
3436 | [ ] \
3437 | [ ]_| <-- old scalar loop to handle remainder.
3438 \ |
3439 \ v
3440 >[ ] <-- exit block.
3441 ...
3442 */
3443
3444 BasicBlock *OldBasicBlock = OrigLoop->getHeader();
3445 BasicBlock *VectorPH = OrigLoop->getLoopPreheader();
3446 BasicBlock *ExitBlock = OrigLoop->getExitBlock();
3447 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3447, __extension__ __PRETTY_FUNCTION__))
;
3448 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3448, __extension__ __PRETTY_FUNCTION__))
;
3449
3450 // Some loops have a single integer induction variable, while other loops
3451 // don't. One example is c++ iterators that often have multiple pointer
3452 // induction variables. In the code below we also support a case where we
3453 // don't have a single induction variable.
3454 //
3455 // We try to obtain an induction variable from the original loop as hard
3456 // as possible. However if we don't find one that:
3457 // - is an integer
3458 // - counts from zero, stepping by one
3459 // - is the size of the widest induction variable type
3460 // then we create a new one.
3461 OldInduction = Legal->getPrimaryInduction();
3462 Type *IdxTy = Legal->getWidestInductionType();
3463
3464 // Split the single block loop into the two loop structure described above.
3465 BasicBlock *VecBody =
3466 VectorPH->splitBasicBlock(VectorPH->getTerminator(), "vector.body");
3467 BasicBlock *MiddleBlock =
3468 VecBody->splitBasicBlock(VecBody->getTerminator(), "middle.block");
3469 BasicBlock *ScalarPH =
3470 MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), "scalar.ph");
3471
3472 // Create and register the new vector loop.
3473 Loop *Lp = LI->AllocateLoop();
3474 Loop *ParentLoop = OrigLoop->getParentLoop();
3475
3476 // Insert the new loop into the loop nest and register the new basic blocks
3477 // before calling any utilities such as SCEV that require valid LoopInfo.
3478 if (ParentLoop) {
3479 ParentLoop->addChildLoop(Lp);
3480 ParentLoop->addBasicBlockToLoop(ScalarPH, *LI);
3481 ParentLoop->addBasicBlockToLoop(MiddleBlock, *LI);
3482 } else {
3483 LI->addTopLevelLoop(Lp);
3484 }
3485 Lp->addBasicBlockToLoop(VecBody, *LI);
3486
3487 // Find the loop boundaries.
3488 Value *Count = getOrCreateTripCount(Lp);
3489
3490 Value *StartIdx = ConstantInt::get(IdxTy, 0);
3491
3492 // Now, compare the new count to zero. If it is zero skip the vector loop and
3493 // jump to the scalar loop. This check also covers the case where the
3494 // backedge-taken count is uint##_max: adding one to it will overflow leading
3495 // to an incorrect trip count of zero. In this (rare) case we will also jump
3496 // to the scalar loop.
3497 emitMinimumIterationCountCheck(Lp, ScalarPH);
3498
3499 // Generate the code to check any assumptions that we've made for SCEV
3500 // expressions.
3501 emitSCEVChecks(Lp, ScalarPH);
3502
3503 // Generate the code that checks in runtime if arrays overlap. We put the
3504 // checks into a separate block to make the more common case of few elements
3505 // faster.
3506 emitMemRuntimeChecks(Lp, ScalarPH);
3507
3508 // Generate the induction variable.
3509 // The loop step is equal to the vectorization factor (num of SIMD elements)
3510 // times the unroll factor (num of SIMD instructions).
3511 Value *CountRoundDown = getOrCreateVectorTripCount(Lp);
3512 Constant *Step = ConstantInt::get(IdxTy, VF * UF);
3513 Induction =
3514 createInductionVariable(Lp, StartIdx, CountRoundDown, Step,
3515 getDebugLocFromInstOrOperands(OldInduction));
3516
3517 // We are going to resume the execution of the scalar loop.
3518 // Go over all of the induction variables that we found and fix the
3519 // PHIs that are left in the scalar version of the loop.
3520 // The starting values of PHI nodes depend on the counter of the last
3521 // iteration in the vectorized loop.
3522 // If we come from a bypass edge then we need to start from the original
3523 // start value.
3524
3525 // This variable saves the new starting index for the scalar loop. It is used
3526 // to test if there are any tail iterations left once the vector loop has
3527 // completed.
3528 LoopVectorizationLegality::InductionList *List = Legal->getInductionVars();
3529 for (auto &InductionEntry : *List) {
3530 PHINode *OrigPhi = InductionEntry.first;
3531 InductionDescriptor II = InductionEntry.second;
3532
3533 // Create phi nodes to merge from the backedge-taken check block.
3534 PHINode *BCResumeVal = PHINode::Create(
3535 OrigPhi->getType(), 3, "bc.resume.val", ScalarPH->getTerminator());
3536 Value *&EndValue = IVEndValues[OrigPhi];
3537 if (OrigPhi == OldInduction) {
3538 // We know what the end value is.
3539 EndValue = CountRoundDown;
3540 } else {
3541 IRBuilder<> B(Lp->getLoopPreheader()->getTerminator());
3542 Type *StepType = II.getStep()->getType();
3543 Instruction::CastOps CastOp =
3544 CastInst::getCastOpcode(CountRoundDown, true, StepType, true);
3545 Value *CRD = B.CreateCast(CastOp, CountRoundDown, StepType, "cast.crd");
3546 const DataLayout &DL = OrigLoop->getHeader()->getModule()->getDataLayout();
3547 EndValue = II.transform(B, CRD, PSE.getSE(), DL);
3548 EndValue->setName("ind.end");
3549 }
3550
3551 // The new PHI merges the original incoming value, in case of a bypass,
3552 // or the value at the end of the vectorized loop.
3553 BCResumeVal->addIncoming(EndValue, MiddleBlock);
3554
3555 // Fix the scalar body counter (PHI node).
3556 unsigned BlockIdx = OrigPhi->getBasicBlockIndex(ScalarPH);
3557
3558 // The old induction's phi node in the scalar body needs the truncated
3559 // value.
3560 for (BasicBlock *BB : LoopBypassBlocks)
3561 BCResumeVal->addIncoming(II.getStartValue(), BB);
3562 OrigPhi->setIncomingValue(BlockIdx, BCResumeVal);
3563 }
3564
3565 // Add a check in the middle block to see if we have completed
3566 // all of the iterations in the first vector loop.
3567 // If (N - N%VF) == N, then we *don't* need to run the remainder.
3568 Value *CmpN =
3569 CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, Count,
3570 CountRoundDown, "cmp.n", MiddleBlock->getTerminator());
3571 ReplaceInstWithInst(MiddleBlock->getTerminator(),
3572 BranchInst::Create(ExitBlock, ScalarPH, CmpN));
3573
3574 // Get ready to start creating new instructions into the vectorized body.
3575 Builder.SetInsertPoint(&*VecBody->getFirstInsertionPt());
3576
3577 // Save the state.
3578 LoopVectorPreHeader = Lp->getLoopPreheader();
3579 LoopScalarPreHeader = ScalarPH;
3580 LoopMiddleBlock = MiddleBlock;
3581 LoopExitBlock = ExitBlock;
3582 LoopVectorBody = VecBody;
3583 LoopScalarBody = OldBasicBlock;
3584
3585 // Keep all loop hints from the original loop on the vector loop (we'll
3586 // replace the vectorizer-specific hints below).
3587 if (MDNode *LID = OrigLoop->getLoopID())
3588 Lp->setLoopID(LID);
3589
3590 LoopVectorizeHints Hints(Lp, true, *ORE);
3591 Hints.setAlreadyVectorized();
3592
3593 return LoopVectorPreHeader;
3594}
3595
3596// Fix up external users of the induction variable. At this point, we are
3597// in LCSSA form, with all external PHIs that use the IV having one input value,
3598// coming from the remainder loop. We need those PHIs to also have a correct
3599// value for the IV when arriving directly from the middle block.
3600void InnerLoopVectorizer::fixupIVUsers(PHINode *OrigPhi,
3601 const InductionDescriptor &II,
3602 Value *CountRoundDown, Value *EndValue,
3603 BasicBlock *MiddleBlock) {
3604 // There are two kinds of external IV usages - those that use the value
3605 // computed in the last iteration (the PHI) and those that use the penultimate
3606 // value (the value that feeds into the phi from the loop latch).
3607 // We allow both, but they, obviously, have different values.
3608
3609 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3609, __extension__ __PRETTY_FUNCTION__))
;
3610
3611 DenseMap<Value *, Value *> MissingVals;
3612
3613 // An external user of the last iteration's value should see the value that
3614 // the remainder loop uses to initialize its own IV.
3615 Value *PostInc = OrigPhi->getIncomingValueForBlock(OrigLoop->getLoopLatch());
3616 for (User *U : PostInc->users()) {
3617 Instruction *UI = cast<Instruction>(U);
3618 if (!OrigLoop->contains(UI)) {
3619 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3619, __extension__ __PRETTY_FUNCTION__))
;
3620 MissingVals[UI] = EndValue;
3621 }
3622 }
3623
3624 // An external user of the penultimate value need to see EndValue - Step.
3625 // The simplest way to get this is to recompute it from the constituent SCEVs,
3626 // that is Start + (Step * (CRD - 1)).
3627 for (User *U : OrigPhi->users()) {
3628 auto *UI = cast<Instruction>(U);
3629 if (!OrigLoop->contains(UI)) {
3630 const DataLayout &DL =
3631 OrigLoop->getHeader()->getModule()->getDataLayout();
3632 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3632, __extension__ __PRETTY_FUNCTION__))
;
3633
3634 IRBuilder<> B(MiddleBlock->getTerminator());
3635 Value *CountMinusOne = B.CreateSub(
3636 CountRoundDown, ConstantInt::get(CountRoundDown->getType(), 1));
3637 Value *CMO =
3638 !II.getStep()->getType()->isIntegerTy()
3639 ? B.CreateCast(Instruction::SIToFP, CountMinusOne,
3640 II.getStep()->getType())
3641 : B.CreateSExtOrTrunc(CountMinusOne, II.getStep()->getType());
3642 CMO->setName("cast.cmo");
3643 Value *Escape = II.transform(B, CMO, PSE.getSE(), DL);
3644 Escape->setName("ind.escape");
3645 MissingVals[UI] = Escape;
3646 }
3647 }
3648
3649 for (auto &I : MissingVals) {
3650 PHINode *PHI = cast<PHINode>(I.first);
3651 // One corner case we have to handle is two IVs "chasing" each-other,
3652 // that is %IV2 = phi [...], [ %IV1, %latch ]
3653 // In this case, if IV1 has an external use, we need to avoid adding both
3654 // "last value of IV1" and "penultimate value of IV2". So, verify that we
3655 // don't already have an incoming value for the middle block.
3656 if (PHI->getBasicBlockIndex(MiddleBlock) == -1)
3657 PHI->addIncoming(I.second, MiddleBlock);
3658 }
3659}
3660
3661namespace {
3662
3663struct CSEDenseMapInfo {
3664 static bool canHandle(const Instruction *I) {
3665 return isa<InsertElementInst>(I) || isa<ExtractElementInst>(I) ||
3666 isa<ShuffleVectorInst>(I) || isa<GetElementPtrInst>(I);
3667 }
3668
3669 static inline Instruction *getEmptyKey() {
3670 return DenseMapInfo<Instruction *>::getEmptyKey();
3671 }
3672
3673 static inline Instruction *getTombstoneKey() {
3674 return DenseMapInfo<Instruction *>::getTombstoneKey();
3675 }
3676
3677 static unsigned getHashValue(const Instruction *I) {
3678 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3678, __extension__ __PRETTY_FUNCTION__))
;
3679 return hash_combine(I->getOpcode(), hash_combine_range(I->value_op_begin(),
3680 I->value_op_end()));
3681 }
3682
3683 static bool isEqual(const Instruction *LHS, const Instruction *RHS) {
3684 if (LHS == getEmptyKey() || RHS == getEmptyKey() ||
3685 LHS == getTombstoneKey() || RHS == getTombstoneKey())
3686 return LHS == RHS;
3687 return LHS->isIdenticalTo(RHS);
3688 }
3689};
3690
3691} // end anonymous namespace
3692
3693///\brief Perform cse of induction variable instructions.
3694static void cse(BasicBlock *BB) {
3695 // Perform simple cse.
3696 SmallDenseMap<Instruction *, Instruction *, 4, CSEDenseMapInfo> CSEMap;
3697 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) {
3698 Instruction *In = &*I++;
3699
3700 if (!CSEDenseMapInfo::canHandle(In))
3701 continue;
3702
3703 // Check if we can replace this instruction with any of the
3704 // visited instructions.
3705 if (Instruction *V = CSEMap.lookup(In)) {
3706 In->replaceAllUsesWith(V);
3707 In->eraseFromParent();
3708 continue;
3709 }
3710
3711 CSEMap[In] = In;
3712 }
3713}
3714
3715/// \brief Estimate the overhead of scalarizing an instruction. This is a
3716/// convenience wrapper for the type-based getScalarizationOverhead API.
3717static unsigned getScalarizationOverhead(Instruction *I, unsigned VF,
3718 const TargetTransformInfo &TTI) {
3719 if (VF == 1)
3720 return 0;
3721
3722 unsigned Cost = 0;
3723 Type *RetTy = ToVectorTy(I->getType(), VF);
3724 if (!RetTy->isVoidTy() &&
3725 (!isa<LoadInst>(I) ||
3726 !TTI.supportsEfficientVectorElementLoadStore()))
3727 Cost += TTI.getScalarizationOverhead(RetTy, true, false);
3728
3729 if (CallInst *CI = dyn_cast<CallInst>(I)) {
3730 SmallVector<const Value *, 4> Operands(CI->arg_operands());
3731 Cost += TTI.getOperandsScalarizationOverhead(Operands, VF);
3732 }
3733 else if (!isa<StoreInst>(I) ||
3734 !TTI.supportsEfficientVectorElementLoadStore()) {
3735 SmallVector<const Value *, 4> Operands(I->operand_values());
3736 Cost += TTI.getOperandsScalarizationOverhead(Operands, VF);
3737 }
3738
3739 return Cost;
3740}
3741
3742// Estimate cost of a call instruction CI if it were vectorized with factor VF.
3743// Return the cost of the instruction, including scalarization overhead if it's
3744// needed. The flag NeedToScalarize shows if the call needs to be scalarized -
3745// i.e. either vector version isn't available, or is too expensive.
3746static unsigned getVectorCallCost(CallInst *CI, unsigned VF,
3747 const TargetTransformInfo &TTI,
3748 const TargetLibraryInfo *TLI,
3749 bool &NeedToScalarize) {
3750 Function *F = CI->getCalledFunction();
3751 StringRef FnName = CI->getCalledFunction()->getName();
3752 Type *ScalarRetTy = CI->getType();
3753 SmallVector<Type *, 4> Tys, ScalarTys;
3754 for (auto &ArgOp : CI->arg_operands())
3755 ScalarTys.push_back(ArgOp->getType());
3756
3757 // Estimate cost of scalarized vector call. The source operands are assumed
3758 // to be vectors, so we need to extract individual elements from there,
3759 // execute VF scalar calls, and then gather the result into the vector return
3760 // value.
3761 unsigned ScalarCallCost = TTI.getCallInstrCost(F, ScalarRetTy, ScalarTys);
3762 if (VF == 1)
3763 return ScalarCallCost;
3764
3765 // Compute corresponding vector type for return value and arguments.
3766 Type *RetTy = ToVectorTy(ScalarRetTy, VF);
3767 for (Type *ScalarTy : ScalarTys)
3768 Tys.push_back(ToVectorTy(ScalarTy, VF));
3769
3770 // Compute costs of unpacking argument values for the scalar calls and
3771 // packing the return values to a vector.
3772 unsigned ScalarizationCost = getScalarizationOverhead(CI, VF, TTI);
3773
3774 unsigned Cost = ScalarCallCost * VF + ScalarizationCost;
3775
3776 // If we can't emit a vector call for this function, then the currently found
3777 // cost is the cost we need to return.
3778 NeedToScalarize = true;
3779 if (!TLI || !TLI->isFunctionVectorizable(FnName, VF) || CI->isNoBuiltin())
3780 return Cost;
3781
3782 // If the corresponding vector cost is cheaper, return its cost.
3783 unsigned VectorCallCost = TTI.getCallInstrCost(nullptr, RetTy, Tys);
3784 if (VectorCallCost < Cost) {
3785 NeedToScalarize = false;
3786 return VectorCallCost;
3787 }
3788 return Cost;
3789}
3790
3791// Estimate cost of an intrinsic call instruction CI if it were vectorized with
3792// factor VF. Return the cost of the instruction, including scalarization
3793// overhead if it's needed.
3794static unsigned getVectorIntrinsicCost(CallInst *CI, unsigned VF,
3795 const TargetTransformInfo &TTI,
3796 const TargetLibraryInfo *TLI) {
3797 Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
3798 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3798, __extension__ __PRETTY_FUNCTION__))
;
3799
3800 FastMathFlags FMF;
3801 if (auto *FPMO = dyn_cast<FPMathOperator>(CI))
3802 FMF = FPMO->getFastMathFlags();
3803
3804 SmallVector<Value *, 4> Operands(CI->arg_operands());
3805 return TTI.getIntrinsicInstrCost(ID, CI->getType(), Operands, FMF, VF);
3806}
3807
3808static Type *smallestIntegerVectorType(Type *T1, Type *T2) {
3809 auto *I1 = cast<IntegerType>(T1->getVectorElementType());
3810 auto *I2 = cast<IntegerType>(T2->getVectorElementType());
3811 return I1->getBitWidth() < I2->getBitWidth() ? T1 : T2;
3812}
3813static Type *largestIntegerVectorType(Type *T1, Type *T2) {
3814 auto *I1 = cast<IntegerType>(T1->getVectorElementType());
3815 auto *I2 = cast<IntegerType>(T2->getVectorElementType());
3816 return I1->getBitWidth() > I2->getBitWidth() ? T1 : T2;
3817}
3818
3819void InnerLoopVectorizer::truncateToMinimalBitwidths() {
3820 // For every instruction `I` in MinBWs, truncate the operands, create a
3821 // truncated version of `I` and reextend its result. InstCombine runs
3822 // later and will remove any ext/trunc pairs.
3823 SmallPtrSet<Value *, 4> Erased;
3824 for (const auto &KV : Cost->getMinimalBitwidths()) {
3825 // If the value wasn't vectorized, we must maintain the original scalar
3826 // type. The absence of the value from VectorLoopValueMap indicates that it
3827 // wasn't vectorized.
3828 if (!VectorLoopValueMap.hasAnyVectorValue(KV.first))
3829 continue;
3830 for (unsigned Part = 0; Part < UF; ++Part) {
3831 Value *I = getOrCreateVectorValue(KV.first, Part);
3832 if (Erased.count(I) || I->use_empty() || !isa<Instruction>(I))
3833 continue;
3834 Type *OriginalTy = I->getType();
3835 Type *ScalarTruncatedTy =
3836 IntegerType::get(OriginalTy->getContext(), KV.second);
3837 Type *TruncatedTy = VectorType::get(ScalarTruncatedTy,
3838 OriginalTy->getVectorNumElements());
3839 if (TruncatedTy == OriginalTy)
3840 continue;
3841
3842 IRBuilder<> B(cast<Instruction>(I));
3843 auto ShrinkOperand = [&](Value *V) -> Value * {
3844 if (auto *ZI = dyn_cast<ZExtInst>(V))
3845 if (ZI->getSrcTy() == TruncatedTy)
3846 return ZI->getOperand(0);
3847 return B.CreateZExtOrTrunc(V, TruncatedTy);
3848 };
3849
3850 // The actual instruction modification depends on the instruction type,
3851 // unfortunately.
3852 Value *NewI = nullptr;
3853 if (auto *BO = dyn_cast<BinaryOperator>(I)) {
3854 NewI = B.CreateBinOp(BO->getOpcode(), ShrinkOperand(BO->getOperand(0)),
3855 ShrinkOperand(BO->getOperand(1)));
3856
3857 // Any wrapping introduced by shrinking this operation shouldn't be
3858 // considered undefined behavior. So, we can't unconditionally copy
3859 // arithmetic wrapping flags to NewI.
3860 cast<BinaryOperator>(NewI)->copyIRFlags(I, /*IncludeWrapFlags=*/false);
3861 } else if (auto *CI = dyn_cast<ICmpInst>(I)) {
3862 NewI =
3863 B.CreateICmp(CI->getPredicate(), ShrinkOperand(CI->getOperand(0)),
3864 ShrinkOperand(CI->getOperand(1)));
3865 } else if (auto *SI = dyn_cast<SelectInst>(I)) {
3866 NewI = B.CreateSelect(SI->getCondition(),
3867 ShrinkOperand(SI->getTrueValue()),
3868 ShrinkOperand(SI->getFalseValue()));
3869 } else if (auto *CI = dyn_cast<CastInst>(I)) {
3870 switch (CI->getOpcode()) {
3871 default:
3872 llvm_unreachable("Unhandled cast!")::llvm::llvm_unreachable_internal("Unhandled cast!", "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3872)
;
3873 case Instruction::Trunc:
3874 NewI = ShrinkOperand(CI->getOperand(0));
3875 break;
3876 case Instruction::SExt:
3877 NewI = B.CreateSExtOrTrunc(
3878 CI->getOperand(0),
3879 smallestIntegerVectorType(OriginalTy, TruncatedTy));
3880 break;
3881 case Instruction::ZExt:
3882 NewI = B.CreateZExtOrTrunc(
3883 CI->getOperand(0),
3884 smallestIntegerVectorType(OriginalTy, TruncatedTy));
3885 break;
3886 }
3887 } else if (auto *SI = dyn_cast<ShuffleVectorInst>(I)) {
3888 auto Elements0 = SI->getOperand(0)->getType()->getVectorNumElements();
3889 auto *O0 = B.CreateZExtOrTrunc(
3890 SI->getOperand(0), VectorType::get(ScalarTruncatedTy, Elements0));
3891 auto Elements1 = SI->getOperand(1)->getType()->getVectorNumElements();
3892 auto *O1 = B.CreateZExtOrTrunc(
3893 SI->getOperand(1), VectorType::get(ScalarTruncatedTy, Elements1));
3894
3895 NewI = B.CreateShuffleVector(O0, O1, SI->getMask());
3896 } else if (isa<LoadInst>(I)) {
3897 // Don't do anything with the operands, just extend the result.
3898 continue;
3899 } else if (auto *IE = dyn_cast<InsertElementInst>(I)) {
3900 auto Elements = IE->getOperand(0)->getType()->getVectorNumElements();
3901 auto *O0 = B.CreateZExtOrTrunc(
3902 IE->getOperand(0), VectorType::get(ScalarTruncatedTy, Elements));
3903 auto *O1 = B.CreateZExtOrTrunc(IE->getOperand(1), ScalarTruncatedTy);
3904 NewI = B.CreateInsertElement(O0, O1, IE->getOperand(2));
3905 } else if (auto *EE = dyn_cast<ExtractElementInst>(I)) {
3906 auto Elements = EE->getOperand(0)->getType()->getVectorNumElements();
3907 auto *O0 = B.CreateZExtOrTrunc(
3908 EE->getOperand(0), VectorType::get(ScalarTruncatedTy, Elements));
3909 NewI = B.CreateExtractElement(O0, EE->getOperand(2));
3910 } else {
3911 llvm_unreachable("Unhandled instruction type!")::llvm::llvm_unreachable_internal("Unhandled instruction type!"
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 3911)
;
3912 }
3913
3914 // Lastly, extend the result.
3915 NewI->takeName(cast<Instruction>(I));
3916 Value *Res = B.CreateZExtOrTrunc(NewI, OriginalTy);
3917 I->replaceAllUsesWith(Res);
3918 cast<Instruction>(I)->eraseFromParent();
3919 Erased.insert(I);
3920 VectorLoopValueMap.resetVectorValue(KV.first, Part, Res);
3921 }
3922 }
3923
3924 // We'll have created a bunch of ZExts that are now parentless. Clean up.
3925 for (const auto &KV : Cost->getMinimalBitwidths()) {
3926 // If the value wasn't vectorized, we must maintain the original scalar
3927 // type. The absence of the value from VectorLoopValueMap indicates that it
3928 // wasn't vectorized.
3929 if (!VectorLoopValueMap.hasAnyVectorValue(KV.first))
3930 continue;
3931 for (unsigned Part = 0; Part < UF; ++Part) {
3932 Value *I = getOrCreateVectorValue(KV.first, Part);
3933 ZExtInst *Inst = dyn_cast<ZExtInst>(I);
3934 if (Inst && Inst->use_empty()) {
3935 Value *NewI = Inst->getOperand(0);
3936 Inst->eraseFromParent();
3937 VectorLoopValueMap.resetVectorValue(KV.first, Part, NewI);
3938 }
3939 }
3940 }
3941}
3942
3943void InnerLoopVectorizer::fixVectorizedLoop() {
3944 // Insert truncates and extends for any truncated instructions as hints to
3945 // InstCombine.
3946 if (VF > 1)
3947 truncateToMinimalBitwidths();
3948
3949 // At this point every instruction in the original loop is widened to a
3950 // vector form. Now we need to fix the recurrences in the loop. These PHI
3951 // nodes are currently empty because we did not want to introduce cycles.
3952 // This is the second stage of vectorizing recurrences.
3953 fixCrossIterationPHIs();
3954
3955 // Update the dominator tree.
3956 //
3957 // FIXME: After creating the structure of the new loop, the dominator tree is
3958 // no longer up-to-date, and it remains that way until we update it
3959 // here. An out-of-date dominator tree is problematic for SCEV,
3960 // because SCEVExpander uses it to guide code generation. The
3961 // vectorizer use SCEVExpanders in several places. Instead, we should
3962 // keep the dominator tree up-to-date as we go.
3963 updateAnalysis();
3964
3965 // Fix-up external users of the induction variables.
3966 for (auto &Entry : *Legal->getInductionVars())
3967 fixupIVUsers(Entry.first, Entry.second,
3968 getOrCreateVectorTripCount(LI->getLoopFor(LoopVectorBody)),
3969 IVEndValues[Entry.first], LoopMiddleBlock);
3970
3971 fixLCSSAPHIs();
3972 for (Instruction *PI : PredicatedInstructions)
3973 sinkScalarOperands(&*PI);
3974
3975 // Remove redundant induction instructions.
3976 cse(LoopVectorBody);
3977}
3978
3979void InnerLoopVectorizer::fixCrossIterationPHIs() {
3980 // In order to support recurrences we need to be able to vectorize Phi nodes.
3981 // Phi nodes have cycles, so we need to vectorize them in two stages. This is
3982 // stage #2: We now need to fix the recurrences by adding incoming edges to
3983 // the currently empty PHI nodes. At this point every instruction in the
3984 // original loop is widened to a vector form so we can use them to construct
3985 // the incoming edges.
3986 for (PHINode &Phi : OrigLoop->getHeader()->phis()) {
3987 // Handle first-order recurrences and reductions that need to be fixed.
3988 if (Legal->isFirstOrderRecurrence(&Phi))
3989 fixFirstOrderRecurrence(&Phi);
3990 else if (Legal->isReductionVariable(&Phi))
3991 fixReduction(&Phi);
3992 }
3993}
3994
3995void InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi) {
3996 // This is the second phase of vectorizing first-order recurrences. An
3997 // overview of the transformation is described below. Suppose we have the
3998 // following loop.
3999 //
4000 // for (int i = 0; i < n; ++i)
4001 // b[i] = a[i] - a[i - 1];
4002 //
4003 // There is a first-order recurrence on "a". For this loop, the shorthand
4004 // scalar IR looks like:
4005 //
4006 // scalar.ph:
4007 // s_init = a[-1]
4008 // br scalar.body
4009 //
4010 // scalar.body:
4011 // i = phi [0, scalar.ph], [i+1, scalar.body]
4012 // s1 = phi [s_init, scalar.ph], [s2, scalar.body]
4013 // s2 = a[i]
4014 // b[i] = s2 - s1
4015 // br cond, scalar.body, ...
4016 //
4017 // In this example, s1 is a recurrence because it's value depends on the
4018 // previous iteration. In the first phase of vectorization, we created a
4019 // temporary value for s1. We now complete the vectorization and produce the
4020 // shorthand vector IR shown below (for VF = 4, UF = 1).
4021 //
4022 // vector.ph:
4023 // v_init = vector(..., ..., ..., a[-1])
4024 // br vector.body
4025 //
4026 // vector.body
4027 // i = phi [0, vector.ph], [i+4, vector.body]
4028 // v1 = phi [v_init, vector.ph], [v2, vector.body]
4029 // v2 = a[i, i+1, i+2, i+3];
4030 // v3 = vector(v1(3), v2(0, 1, 2))
4031 // b[i, i+1, i+2, i+3] = v2 - v3
4032 // br cond, vector.body, middle.block
4033 //
4034 // middle.block:
4035 // x = v2(3)
4036 // br scalar.ph
4037 //
4038 // scalar.ph:
4039 // s_init = phi [x, middle.block], [a[-1], otherwise]
4040 // br scalar.body
4041 //
4042 // After execution completes the vector loop, we extract the next value of
4043 // the recurrence (x) to use as the initial value in the scalar loop.
4044
4045 // Get the original loop preheader and single loop latch.
4046 auto *Preheader = OrigLoop->getLoopPreheader();
4047 auto *Latch = OrigLoop->getLoopLatch();
4048
4049 // Get the initial and previous values of the scalar recurrence.
4050 auto *ScalarInit = Phi->getIncomingValueForBlock(Preheader);
4051 auto *Previous = Phi->getIncomingValueForBlock(Latch);
4052
4053 // Create a vector from the initial value.
4054 auto *VectorInit = ScalarInit;
4055 if (VF > 1) {
4056 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
4057 VectorInit = Builder.CreateInsertElement(
4058 UndefValue::get(VectorType::get(VectorInit->getType(), VF)), VectorInit,
4059 Builder.getInt32(VF - 1), "vector.recur.init");
4060 }
4061
4062 // We constructed a temporary phi node in the first phase of vectorization.
4063 // This phi node will eventually be deleted.
4064 Builder.SetInsertPoint(
4065 cast<Instruction>(VectorLoopValueMap.getVectorValue(Phi, 0)));
4066
4067 // Create a phi node for the new recurrence. The current value will either be
4068 // the initial value inserted into a vector or loop-varying vector value.
4069 auto *VecPhi = Builder.CreatePHI(VectorInit->getType(), 2, "vector.recur");
4070 VecPhi->addIncoming(VectorInit, LoopVectorPreHeader);
4071
4072 // Get the vectorized previous value of the last part UF - 1. It appears last
4073 // among all unrolled iterations, due to the order of their construction.
4074 Value *PreviousLastPart = getOrCreateVectorValue(Previous, UF - 1);
4075
4076 // Set the insertion point after the previous value if it is an instruction.
4077 // Note that the previous value may have been constant-folded so it is not
4078 // guaranteed to be an instruction in the vector loop. Also, if the previous
4079 // value is a phi node, we should insert after all the phi nodes to avoid
4080 // breaking basic block verification.
4081 if (LI->getLoopFor(LoopVectorBody)->isLoopInvariant(PreviousLastPart) ||
4082 isa<PHINode>(PreviousLastPart))
4083 Builder.SetInsertPoint(&*LoopVectorBody->getFirstInsertionPt());
4084 else
4085 Builder.SetInsertPoint(
4086 &*++BasicBlock::iterator(cast<Instruction>(PreviousLastPart)));
4087
4088 // We will construct a vector for the recurrence by combining the values for
4089 // the current and previous iterations. This is the required shuffle mask.
4090 SmallVector<Constant *, 8> ShuffleMask(VF);
4091 ShuffleMask[0] = Builder.getInt32(VF - 1);
4092 for (unsigned I = 1; I < VF; ++I)
4093 ShuffleMask[I] = Builder.getInt32(I + VF - 1);
4094
4095 // The vector from which to take the initial value for the current iteration
4096 // (actual or unrolled). Initially, this is the vector phi node.
4097 Value *Incoming = VecPhi;
4098
4099 // Shuffle the current and previous vector and update the vector parts.
4100 for (unsigned Part = 0; Part < UF; ++Part) {
4101 Value *PreviousPart = getOrCreateVectorValue(Previous, Part);
4102 Value *PhiPart = VectorLoopValueMap.getVectorValue(Phi, Part);
4103 auto *Shuffle =
4104 VF > 1 ? Builder.CreateShuffleVector(Incoming, PreviousPart,
4105 ConstantVector::get(ShuffleMask))
4106 : Incoming;
4107 PhiPart->replaceAllUsesWith(Shuffle);
4108 cast<Instruction>(PhiPart)->eraseFromParent();
4109 VectorLoopValueMap.resetVectorValue(Phi, Part, Shuffle);
4110 Incoming = PreviousPart;
4111 }
4112
4113 // Fix the latch value of the new recurrence in the vector loop.
4114 VecPhi->addIncoming(Incoming, LI->getLoopFor(LoopVectorBody)->getLoopLatch());
4115
4116 // Extract the last vector element in the middle block. This will be the
4117 // initial value for the recurrence when jumping to the scalar loop.
4118 auto *ExtractForScalar = Incoming;
4119 if (VF > 1) {
4120 Builder.SetInsertPoint(LoopMiddleBlock->getTerminator());
4121 ExtractForScalar = Builder.CreateExtractElement(
4122 ExtractForScalar, Builder.getInt32(VF - 1), "vector.recur.extract");
4123 }
4124 // Extract the second last element in the middle block if the
4125 // Phi is used outside the loop. We need to extract the phi itself
4126 // and not the last element (the phi update in the current iteration). This
4127 // will be the value when jumping to the exit block from the LoopMiddleBlock,
4128 // when the scalar loop is not run at all.
4129 Value *ExtractForPhiUsedOutsideLoop = nullptr;
4130 if (VF > 1)
4131 ExtractForPhiUsedOutsideLoop = Builder.CreateExtractElement(
4132 Incoming, Builder.getInt32(VF - 2), "vector.recur.extract.for.phi");
4133 // When loop is unrolled without vectorizing, initialize
4134 // ExtractForPhiUsedOutsideLoop with the value just prior to unrolled value of
4135 // `Incoming`. This is analogous to the vectorized case above: extracting the
4136 // second last element when VF > 1.
4137 else if (UF > 1)
4138 ExtractForPhiUsedOutsideLoop = getOrCreateVectorValue(Previous, UF - 2);
4139
4140 // Fix the initial value of the original recurrence in the scalar loop.
4141 Builder.SetInsertPoint(&*LoopScalarPreHeader->begin());
4142 auto *Start = Builder.CreatePHI(Phi->getType(), 2, "scalar.recur.init");
4143 for (auto *BB : predecessors(LoopScalarPreHeader)) {
4144 auto *Incoming = BB == LoopMiddleBlock ? ExtractForScalar : ScalarInit;
4145 Start->addIncoming(Incoming, BB);
4146 }
4147
4148 Phi->setIncomingValue(Phi->getBasicBlockIndex(LoopScalarPreHeader), Start);
4149 Phi->setName("scalar.recur");
4150
4151 // Finally, fix users of the recurrence outside the loop. The users will need
4152 // either the last value of the scalar recurrence or the last value of the
4153 // vector recurrence we extracted in the middle block. Since the loop is in
4154 // LCSSA form, we just need to find the phi node for the original scalar
4155 // recurrence in the exit block, and then add an edge for the middle block.
4156 for (PHINode &LCSSAPhi : LoopExitBlock->phis()) {
4157 if (LCSSAPhi.getIncomingValue(0) == Phi) {
4158 LCSSAPhi.addIncoming(ExtractForPhiUsedOutsideLoop, LoopMiddleBlock);
4159 break;
4160 }
4161 }
4162}
4163
4164void InnerLoopVectorizer::fixReduction(PHINode *Phi) {
4165 Constant *Zero = Builder.getInt32(0);
4166
4167 // Get it's reduction variable descriptor.
4168 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4169, __extension__ __PRETTY_FUNCTION__))
4169 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4169, __extension__ __PRETTY_FUNCTION__))
;
4170 RecurrenceDescriptor RdxDesc = (*Legal->getReductionVars())[Phi];
4171
4172 RecurrenceDescriptor::RecurrenceKind RK = RdxDesc.getRecurrenceKind();
4173 TrackingVH<Value> ReductionStartValue = RdxDesc.getRecurrenceStartValue();
4174 Instruction *LoopExitInst = RdxDesc.getLoopExitInstr();
4175 RecurrenceDescriptor::MinMaxRecurrenceKind MinMaxKind =
4176 RdxDesc.getMinMaxRecurrenceKind();
4177 setDebugLocFromInst(Builder, ReductionStartValue);
4178
4179 // We need to generate a reduction vector from the incoming scalar.
4180 // To do so, we need to generate the 'identity' vector and override
4181 // one of the elements with the incoming scalar reduction. We need
4182 // to do it in the vector-loop preheader.
4183 Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
4184
4185 // This is the vector-clone of the value that leaves the loop.
4186 Type *VecTy = getOrCreateVectorValue(LoopExitInst, 0)->getType();
4187
4188 // Find the reduction identity variable. Zero for addition, or, xor,
4189 // one for multiplication, -1 for And.
4190 Value *Identity;
4191 Value *VectorStart;
4192 if (RK == RecurrenceDescriptor::RK_IntegerMinMax ||
4193 RK == RecurrenceDescriptor::RK_FloatMinMax) {
4194 // MinMax reduction have the start value as their identify.
4195 if (VF == 1) {
4196 VectorStart = Identity = ReductionStartValue;
4197 } else {
4198 VectorStart = Identity =
4199 Builder.CreateVectorSplat(VF, ReductionStartValue, "minmax.ident");
4200 }
4201 } else {
4202 // Handle other reduction kinds:
4203 Constant *Iden = RecurrenceDescriptor::getRecurrenceIdentity(
4204 RK, VecTy->getScalarType());
4205 if (VF == 1) {
4206 Identity = Iden;
4207 // This vector is the Identity vector where the first element is the
4208 // incoming scalar reduction.
4209 VectorStart = ReductionStartValue;
4210 } else {
4211 Identity = ConstantVector::getSplat(VF, Iden);
4212
4213 // This vector is the Identity vector where the first element is the
4214 // incoming scalar reduction.
4215 VectorStart =
4216 Builder.CreateInsertElement(Identity, ReductionStartValue, Zero);
4217 }
4218 }
4219
4220 // Fix the vector-loop phi.
4221
4222 // Reductions do not have to start at zero. They can start with
4223 // any loop invariant values.
4224 BasicBlock *Latch = OrigLoop->getLoopLatch();
4225 Value *LoopVal = Phi->getIncomingValueForBlock(Latch);
4226 for (unsigned Part = 0; Part < UF; ++Part) {
4227 Value *VecRdxPhi = getOrCreateVectorValue(Phi, Part);
4228 Value *Val = getOrCreateVectorValue(LoopVal, Part);
4229 // Make sure to add the reduction stat value only to the
4230 // first unroll part.
4231 Value *StartVal = (Part == 0) ? VectorStart : Identity;
4232 cast<PHINode>(VecRdxPhi)->addIncoming(StartVal, LoopVectorPreHeader);
4233 cast<PHINode>(VecRdxPhi)
4234 ->addIncoming(Val, LI->getLoopFor(LoopVectorBody)->getLoopLatch());
4235 }
4236
4237 // Before each round, move the insertion point right between
4238 // the PHIs and the values we are going to write.
4239 // This allows us to write both PHINodes and the extractelement
4240 // instructions.
4241 Builder.SetInsertPoint(&*LoopMiddleBlock->getFirstInsertionPt());
4242
4243 setDebugLocFromInst(Builder, LoopExitInst);
4244
4245 // If the vector reduction can be performed in a smaller type, we truncate
4246 // then extend the loop exit value to enable InstCombine to evaluate the
4247 // entire expression in the smaller type.
4248 if (VF > 1 && Phi->getType() != RdxDesc.getRecurrenceType()) {
4249 Type *RdxVecTy = VectorType::get(RdxDesc.getRecurrenceType(), VF);
4250 Builder.SetInsertPoint(
4251 LI->getLoopFor(LoopVectorBody)->getLoopLatch()->getTerminator());
4252 VectorParts RdxParts(UF);
4253 for (unsigned Part = 0; Part < UF; ++Part) {
4254 RdxParts[Part] = VectorLoopValueMap.getVectorValue(LoopExitInst, Part);
4255 Value *Trunc = Builder.CreateTrunc(RdxParts[Part], RdxVecTy);
4256 Value *Extnd = RdxDesc.isSigned() ? Builder.CreateSExt(Trunc, VecTy)
4257 : Builder.CreateZExt(Trunc, VecTy);
4258 for (Value::user_iterator UI = RdxParts[Part]->user_begin();
4259 UI != RdxParts[Part]->user_end();)
4260 if (*UI != Trunc) {
4261 (*UI++)->replaceUsesOfWith(RdxParts[Part], Extnd);
4262 RdxParts[Part] = Extnd;
4263 } else {
4264 ++UI;
4265 }
4266 }
4267 Builder.SetInsertPoint(&*LoopMiddleBlock->getFirstInsertionPt());
4268 for (unsigned Part = 0; Part < UF; ++Part) {
4269 RdxParts[Part] = Builder.CreateTrunc(RdxParts[Part], RdxVecTy);
4270 VectorLoopValueMap.resetVectorValue(LoopExitInst, Part, RdxParts[Part]);
4271 }
4272 }
4273
4274 // Reduce all of the unrolled parts into a single vector.
4275 Value *ReducedPartRdx = VectorLoopValueMap.getVectorValue(LoopExitInst, 0);
4276 unsigned Op = RecurrenceDescriptor::getRecurrenceBinOp(RK);
4277 setDebugLocFromInst(Builder, ReducedPartRdx);
4278 for (unsigned Part = 1; Part < UF; ++Part) {
4279 Value *RdxPart = VectorLoopValueMap.getVectorValue(LoopExitInst, Part);
4280 if (Op != Instruction::ICmp && Op != Instruction::FCmp)
4281 // Floating point operations had to be 'fast' to enable the reduction.
4282 ReducedPartRdx = addFastMathFlag(
4283 Builder.CreateBinOp((Instruction::BinaryOps)Op, RdxPart,
4284 ReducedPartRdx, "bin.rdx"));
4285 else
4286 ReducedPartRdx = RecurrenceDescriptor::createMinMaxOp(
4287 Builder, MinMaxKind, ReducedPartRdx, RdxPart);
4288 }
4289
4290 if (VF > 1) {
4291 bool NoNaN = Legal->hasFunNoNaNAttr();
4292 ReducedPartRdx =
4293 createTargetReduction(Builder, TTI, RdxDesc, ReducedPartRdx, NoNaN);
4294 // If the reduction can be performed in a smaller type, we need to extend
4295 // the reduction to the wider type before we branch to the original loop.
4296 if (Phi->getType() != RdxDesc.getRecurrenceType())
4297 ReducedPartRdx =
4298 RdxDesc.isSigned()
4299 ? Builder.CreateSExt(ReducedPartRdx, Phi->getType())
4300 : Builder.CreateZExt(ReducedPartRdx, Phi->getType());
4301 }
4302
4303 // Create a phi node that merges control-flow from the backedge-taken check
4304 // block and the middle block.
4305 PHINode *BCBlockPhi = PHINode::Create(Phi->getType(), 2, "bc.merge.rdx",
4306 LoopScalarPreHeader->getTerminator());
4307 for (unsigned I = 0, E = LoopBypassBlocks.size(); I != E; ++I)
4308 BCBlockPhi->addIncoming(ReductionStartValue, LoopBypassBlocks[I]);
4309 BCBlockPhi->addIncoming(ReducedPartRdx, LoopMiddleBlock);
4310
4311 // Now, we need to fix the users of the reduction variable
4312 // inside and outside of the scalar remainder loop.
4313 // We know that the loop is in LCSSA form. We need to update the
4314 // PHI nodes in the exit blocks.
4315 for (PHINode &LCSSAPhi : LoopExitBlock->phis()) {
4316 // All PHINodes need to have a single entry edge, or two if
4317 // we already fixed them.
4318 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4318, __extension__ __PRETTY_FUNCTION__))
;
4319
4320 // We found a reduction value exit-PHI. Update it with the
4321 // incoming bypass edge.
4322 if (LCSSAPhi.getIncomingValue(0) == LoopExitInst)
4323 LCSSAPhi.addIncoming(ReducedPartRdx, LoopMiddleBlock);
4324 } // end of the LCSSA phi scan.
4325
4326 // Fix the scalar loop reduction variable with the incoming reduction sum
4327 // from the vector body and from the backedge value.
4328 int IncomingEdgeBlockIdx =
4329 Phi->getBasicBlockIndex(OrigLoop->getLoopLatch());
4330 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4330, __extension__ __PRETTY_FUNCTION__))
;
4331 // Pick the other block.
4332 int SelfEdgeBlockIdx = (IncomingEdgeBlockIdx ? 0 : 1);
4333 Phi->setIncomingValue(SelfEdgeBlockIdx, BCBlockPhi);
4334 Phi->setIncomingValue(IncomingEdgeBlockIdx, LoopExitInst);
4335}
4336
4337void InnerLoopVectorizer::fixLCSSAPHIs() {
4338 for (PHINode &LCSSAPhi : LoopExitBlock->phis()) {
4339 if (LCSSAPhi.getNumIncomingValues() == 1) {
4340 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4341, __extension__ __PRETTY_FUNCTION__))
4341 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4341, __extension__ __PRETTY_FUNCTION__))
;
4342 LCSSAPhi.addIncoming(LCSSAPhi.getIncomingValue(0), LoopMiddleBlock);
4343 }
4344 }
4345}
4346
4347void InnerLoopVectorizer::sinkScalarOperands(Instruction *PredInst) {
4348 // The basic block and loop containing the predicated instruction.
4349 auto *PredBB = PredInst->getParent();
4350 auto *VectorLoop = LI->getLoopFor(PredBB);
4351
4352 // Initialize a worklist with the operands of the predicated instruction.
4353 SetVector<Value *> Worklist(PredInst->op_begin(), PredInst->op_end());
4354
4355 // Holds instructions that we need to analyze again. An instruction may be
4356 // reanalyzed if we don't yet know if we can sink it or not.
4357 SmallVector<Instruction *, 8> InstsToReanalyze;
4358
4359 // Returns true if a given use occurs in the predicated block. Phi nodes use
4360 // their operands in their corresponding predecessor blocks.
4361 auto isBlockOfUsePredicated = [&](Use &U) -> bool {
4362 auto *I = cast<Instruction>(U.getUser());
4363 BasicBlock *BB = I->getParent();
4364 if (auto *Phi = dyn_cast<PHINode>(I))
4365 BB = Phi->getIncomingBlock(
4366 PHINode::getIncomingValueNumForOperand(U.getOperandNo()));
4367 return BB == PredBB;
4368 };
4369
4370 // Iteratively sink the scalarized operands of the predicated instruction
4371 // into the block we created for it. When an instruction is sunk, it's
4372 // operands are then added to the worklist. The algorithm ends after one pass
4373 // through the worklist doesn't sink a single instruction.
4374 bool Changed;
4375 do {
4376 // Add the instructions that need to be reanalyzed to the worklist, and
4377 // reset the changed indicator.
4378 Worklist.insert(InstsToReanalyze.begin(), InstsToReanalyze.end());
4379 InstsToReanalyze.clear();
4380 Changed = false;
4381
4382 while (!Worklist.empty()) {
4383 auto *I = dyn_cast<Instruction>(Worklist.pop_back_val());
4384
4385 // We can't sink an instruction if it is a phi node, is already in the
4386 // predicated block, is not in the loop, or may have side effects.
4387 if (!I || isa<PHINode>(I) || I->getParent() == PredBB ||
4388 !VectorLoop->contains(I) || I->mayHaveSideEffects())
4389 continue;
4390
4391 // It's legal to sink the instruction if all its uses occur in the
4392 // predicated block. Otherwise, there's nothing to do yet, and we may
4393 // need to reanalyze the instruction.
4394 if (!llvm::all_of(I->uses(), isBlockOfUsePredicated)) {
4395 InstsToReanalyze.push_back(I);
4396 continue;
4397 }
4398
4399 // Move the instruction to the beginning of the predicated block, and add
4400 // it's operands to the worklist.
4401 I->moveBefore(&*PredBB->getFirstInsertionPt());
4402 Worklist.insert(I->op_begin(), I->op_end());
4403
4404 // The sinking may have enabled other instructions to be sunk, so we will
4405 // need to iterate.
4406 Changed = true;
4407 }
4408 } while (Changed);
4409}
4410
4411void InnerLoopVectorizer::widenPHIInstruction(Instruction *PN, unsigned UF,
4412 unsigned VF) {
4413 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4414, __extension__ __PRETTY_FUNCTION__))
4414 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4414, __extension__ __PRETTY_FUNCTION__))
;
4415
4416 PHINode *P = cast<PHINode>(PN);
4417 // In order to support recurrences we need to be able to vectorize Phi nodes.
4418 // Phi nodes have cycles, so we need to vectorize them in two stages. This is
4419 // stage #1: We create a new vector PHI node with no incoming edges. We'll use
4420 // this value when we vectorize all of the instructions that use the PHI.
4421 if (Legal->isReductionVariable(P) || Legal->isFirstOrderRecurrence(P)) {
4422 for (unsigned Part = 0; Part < UF; ++Part) {
4423 // This is phase one of vectorizing PHIs.
4424 Type *VecTy =
4425 (VF == 1) ? PN->getType() : VectorType::get(PN->getType(), VF);
4426 Value *EntryPart = PHINode::Create(
4427 VecTy, 2, "vec.phi", &*LoopVectorBody->getFirstInsertionPt());
4428 VectorLoopValueMap.setVectorValue(P, Part, EntryPart);
4429 }
4430 return;
4431 }
4432
4433 setDebugLocFromInst(Builder, P);
4434
4435 // This PHINode must be an induction variable.
4436 // Make sure that we know about it.
4437 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4437, __extension__ __PRETTY_FUNCTION__))
;
4438
4439 InductionDescriptor II = Legal->getInductionVars()->lookup(P);
4440 const DataLayout &DL = OrigLoop->getHeader()->getModule()->getDataLayout();
4441
4442 // FIXME: The newly created binary instructions should contain nsw/nuw flags,
4443 // which can be found from the original scalar operations.
4444 switch (II.getKind()) {
4445 case InductionDescriptor::IK_NoInduction:
4446 llvm_unreachable("Unknown induction")::llvm::llvm_unreachable_internal("Unknown induction", "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4446)
;
4447 case InductionDescriptor::IK_IntInduction:
4448 case InductionDescriptor::IK_FpInduction:
4449 llvm_unreachable("Integer/fp induction is handled elsewhere.")::llvm::llvm_unreachable_internal("Integer/fp induction is handled elsewhere."
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4449)
;
4450 case InductionDescriptor::IK_PtrInduction: {
4451 // Handle the pointer induction variable case.
4452 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4452, __extension__ __PRETTY_FUNCTION__))
;
4453 // This is the normalized GEP that starts counting at zero.
4454 Value *PtrInd = Induction;
4455 PtrInd = Builder.CreateSExtOrTrunc(PtrInd, II.getStep()->getType());
4456 // Determine the number of scalars we need to generate for each unroll
4457 // iteration. If the instruction is uniform, we only need to generate the
4458 // first lane. Otherwise, we generate all VF values.
4459 unsigned Lanes = Cost->isUniformAfterVectorization(P, VF) ? 1 : VF;
4460 // These are the scalar results. Notice that we don't generate vector GEPs
4461 // because scalar GEPs result in better code.
4462 for (unsigned Part = 0; Part < UF; ++Part) {
4463 for (unsigned Lane = 0; Lane < Lanes; ++Lane) {
4464 Constant *Idx = ConstantInt::get(PtrInd->getType(), Lane + Part * VF);
4465 Value *GlobalIdx = Builder.CreateAdd(PtrInd, Idx);
4466 Value *SclrGep = II.transform(Builder, GlobalIdx, PSE.getSE(), DL);
4467 SclrGep->setName("next.gep");
4468 VectorLoopValueMap.setScalarValue(P, {Part, Lane}, SclrGep);
4469 }
4470 }
4471 return;
4472 }
4473 }
4474}
4475
4476/// A helper function for checking whether an integer division-related
4477/// instruction may divide by zero (in which case it must be predicated if
4478/// executed conditionally in the scalar code).
4479/// TODO: It may be worthwhile to generalize and check isKnownNonZero().
4480/// Non-zero divisors that are non compile-time constants will not be
4481/// converted into multiplication, so we will still end up scalarizing
4482/// the division, but can do so w/o predication.
4483static bool mayDivideByZero(Instruction &I) {
4484 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4488, __extension__ __PRETTY_FUNCTION__))
4485 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4488, __extension__ __PRETTY_FUNCTION__))
4486 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4488, __extension__ __PRETTY_FUNCTION__))
4487 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4488, __extension__ __PRETTY_FUNCTION__))
4488 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4488, __extension__ __PRETTY_FUNCTION__))
;
4489 Value *Divisor = I.getOperand(1);
4490 auto *CInt = dyn_cast<ConstantInt>(Divisor);
4491 return !CInt || CInt->isZero();
4492}
4493
4494void InnerLoopVectorizer::widenInstruction(Instruction &I) {
4495 switch (I.getOpcode()) {
4496 case Instruction::Br:
4497 case Instruction::PHI:
4498 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4498)
;
4499 case Instruction::GetElementPtr: {
4500 // Construct a vector GEP by widening the operands of the scalar GEP as
4501 // necessary. We mark the vector GEP 'inbounds' if appropriate. A GEP
4502 // results in a vector of pointers when at least one operand of the GEP
4503 // is vector-typed. Thus, to keep the representation compact, we only use
4504 // vector-typed operands for loop-varying values.
4505 auto *GEP = cast<GetElementPtrInst>(&I);
4506
4507 if (VF > 1 && OrigLoop->hasLoopInvariantOperands(GEP)) {
4508 // If we are vectorizing, but the GEP has only loop-invariant operands,
4509 // the GEP we build (by only using vector-typed operands for
4510 // loop-varying values) would be a scalar pointer. Thus, to ensure we
4511 // produce a vector of pointers, we need to either arbitrarily pick an
4512 // operand to broadcast, or broadcast a clone of the original GEP.
4513 // Here, we broadcast a clone of the original.
4514 //
4515 // TODO: If at some point we decide to scalarize instructions having
4516 // loop-invariant operands, this special case will no longer be
4517 // required. We would add the scalarization decision to
4518 // collectLoopScalars() and teach getVectorValue() to broadcast
4519 // the lane-zero scalar value.
4520 auto *Clone = Builder.Insert(GEP->clone());
4521 for (unsigned Part = 0; Part < UF; ++Part) {
4522 Value *EntryPart = Builder.CreateVectorSplat(VF, Clone);
4523 VectorLoopValueMap.setVectorValue(&I, Part, EntryPart);
4524 addMetadata(EntryPart, GEP);
4525 }
4526 } else {
4527 // If the GEP has at least one loop-varying operand, we are sure to
4528 // produce a vector of pointers. But if we are only unrolling, we want
4529 // to produce a scalar GEP for each unroll part. Thus, the GEP we
4530 // produce with the code below will be scalar (if VF == 1) or vector
4531 // (otherwise). Note that for the unroll-only case, we still maintain
4532 // values in the vector mapping with initVector, as we do for other
4533 // instructions.
4534 for (unsigned Part = 0; Part < UF; ++Part) {
4535 // The pointer operand of the new GEP. If it's loop-invariant, we
4536 // won't broadcast it.
4537 auto *Ptr =
4538 OrigLoop->isLoopInvariant(GEP->getPointerOperand())
4539 ? GEP->getPointerOperand()
4540 : getOrCreateVectorValue(GEP->getPointerOperand(), Part);
4541
4542 // Collect all the indices for the new GEP. If any index is
4543 // loop-invariant, we won't broadcast it.
4544 SmallVector<Value *, 4> Indices;
4545 for (auto &U : make_range(GEP->idx_begin(), GEP->idx_end())) {
4546 if (OrigLoop->isLoopInvariant(U.get()))
4547 Indices.push_back(U.get());
4548 else
4549 Indices.push_back(getOrCreateVectorValue(U.get(), Part));
4550 }
4551
4552 // Create the new GEP. Note that this GEP may be a scalar if VF == 1,
4553 // but it should be a vector, otherwise.
4554 auto *NewGEP = GEP->isInBounds()
4555 ? Builder.CreateInBoundsGEP(Ptr, Indices)
4556 : Builder.CreateGEP(Ptr, Indices);
4557 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4558, __extension__ __PRETTY_FUNCTION__))
4558 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4558, __extension__ __PRETTY_FUNCTION__))
;
4559 VectorLoopValueMap.setVectorValue(&I, Part, NewGEP);
4560 addMetadata(NewGEP, GEP);
4561 }
4562 }
4563
4564 break;
4565 }
4566 case Instruction::UDiv:
4567 case Instruction::SDiv:
4568 case Instruction::SRem:
4569 case Instruction::URem:
4570 case Instruction::Add:
4571 case Instruction::FAdd:
4572 case Instruction::Sub:
4573 case Instruction::FSub:
4574 case Instruction::Mul:
4575 case Instruction::FMul:
4576 case Instruction::FDiv:
4577 case Instruction::FRem:
4578 case Instruction::Shl:
4579 case Instruction::LShr:
4580 case Instruction::AShr:
4581 case Instruction::And:
4582 case Instruction::Or:
4583 case Instruction::Xor: {
4584 // Just widen binops.
4585 auto *BinOp = cast<BinaryOperator>(&I);
4586 setDebugLocFromInst(Builder, BinOp);
4587
4588 for (unsigned Part = 0; Part < UF; ++Part) {
4589 Value *A = getOrCreateVectorValue(BinOp->getOperand(0), Part);
4590 Value *B = getOrCreateVectorValue(BinOp->getOperand(1), Part);
4591 Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A, B);
4592
4593 if (BinaryOperator *VecOp = dyn_cast<BinaryOperator>(V))
4594 VecOp->copyIRFlags(BinOp);
4595
4596 // Use this vector value for all users of the original instruction.
4597 VectorLoopValueMap.setVectorValue(&I, Part, V);
4598 addMetadata(V, BinOp);
4599 }
4600
4601 break;
4602 }
4603 case Instruction::Select: {
4604 // Widen selects.
4605 // If the selector is loop invariant we can create a select
4606 // instruction with a scalar condition. Otherwise, use vector-select.
4607 auto *SE = PSE.getSE();
4608 bool InvariantCond =
4609 SE->isLoopInvariant(PSE.getSCEV(I.getOperand(0)), OrigLoop);
4610 setDebugLocFromInst(Builder, &I);
4611
4612 // The condition can be loop invariant but still defined inside the
4613 // loop. This means that we can't just use the original 'cond' value.
4614 // We have to take the 'vectorized' value and pick the first lane.
4615 // Instcombine will make this a no-op.
4616
4617 auto *ScalarCond = getOrCreateScalarValue(I.getOperand(0), {0, 0});
4618
4619 for (unsigned Part = 0; Part < UF; ++Part) {
4620 Value *Cond = getOrCreateVectorValue(I.getOperand(0), Part);
4621 Value *Op0 = getOrCreateVectorValue(I.getOperand(1), Part);
4622 Value *Op1 = getOrCreateVectorValue(I.getOperand(2), Part);
4623 Value *Sel =
4624 Builder.CreateSelect(InvariantCond ? ScalarCond : Cond, Op0, Op1);
4625 VectorLoopValueMap.setVectorValue(&I, Part, Sel);
4626 addMetadata(Sel, &I);
4627 }
4628
4629 break;
4630 }
4631
4632 case Instruction::ICmp:
4633 case Instruction::FCmp: {
4634 // Widen compares. Generate vector compares.
4635 bool FCmp = (I.getOpcode() == Instruction::FCmp);
4636 auto *Cmp = dyn_cast<CmpInst>(&I);
4637 setDebugLocFromInst(Builder, Cmp);
4638 for (unsigned Part = 0; Part < UF; ++Part) {
4639 Value *A = getOrCreateVectorValue(Cmp->getOperand(0), Part);
4640 Value *B = getOrCreateVectorValue(Cmp->getOperand(1), Part);
4641 Value *C = nullptr;
4642 if (FCmp) {
4643 // Propagate fast math flags.
4644 IRBuilder<>::FastMathFlagGuard FMFG(Builder);
4645 Builder.setFastMathFlags(Cmp->getFastMathFlags());
4646 C = Builder.CreateFCmp(Cmp->getPredicate(), A, B);
4647 } else {
4648 C = Builder.CreateICmp(Cmp->getPredicate(), A, B);
4649 }
4650 VectorLoopValueMap.setVectorValue(&I, Part, C);
4651 addMetadata(C, &I);
4652 }
4653
4654 break;
4655 }
4656
4657 case Instruction::ZExt:
4658 case Instruction::SExt:
4659 case Instruction::FPToUI:
4660 case Instruction::FPToSI:
4661 case Instruction::FPExt:
4662 case Instruction::PtrToInt:
4663 case Instruction::IntToPtr:
4664 case Instruction::SIToFP:
4665 case Instruction::UIToFP:
4666 case Instruction::Trunc:
4667 case Instruction::FPTrunc:
4668 case Instruction::BitCast: {
4669 auto *CI = dyn_cast<CastInst>(&I);
4670 setDebugLocFromInst(Builder, CI);
4671
4672 /// Vectorize casts.
4673 Type *DestTy =
4674 (VF == 1) ? CI->getType() : VectorType::get(CI->getType(), VF);
4675
4676 for (unsigned Part = 0; Part < UF; ++Part) {
4677 Value *A = getOrCreateVectorValue(CI->getOperand(0), Part);
4678 Value *Cast = Builder.CreateCast(CI->getOpcode(), A, DestTy);
4679 VectorLoopValueMap.setVectorValue(&I, Part, Cast);
4680 addMetadata(Cast, &I);
4681 }
4682 break;
4683 }
4684
4685 case Instruction::Call: {
4686 // Ignore dbg intrinsics.
4687 if (isa<DbgInfoIntrinsic>(I))
4688 break;
4689 setDebugLocFromInst(Builder, &I);
4690
4691 Module *M = I.getParent()->getParent()->getParent();
4692 auto *CI = cast<CallInst>(&I);
4693
4694 StringRef FnName = CI->getCalledFunction()->getName();
4695 Function *F = CI->getCalledFunction();
4696 Type *RetTy = ToVectorTy(CI->getType(), VF);
4697 SmallVector<Type *, 4> Tys;
4698 for (Value *ArgOperand : CI->arg_operands())
4699 Tys.push_back(ToVectorTy(ArgOperand->getType(), VF));
4700
4701 Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
4702
4703 // The flag shows whether we use Intrinsic or a usual Call for vectorized
4704 // version of the instruction.
4705 // Is it beneficial to perform intrinsic call compared to lib call?
4706 bool NeedToScalarize;
4707 unsigned CallCost = getVectorCallCost(CI, VF, *TTI, TLI, NeedToScalarize);
4708 bool UseVectorIntrinsic =
4709 ID && getVectorIntrinsicCost(CI, VF, *TTI, TLI) <= CallCost;
4710 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4711, __extension__ __PRETTY_FUNCTION__))
4711 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4711, __extension__ __PRETTY_FUNCTION__))
;
4712
4713 for (unsigned Part = 0; Part < UF; ++Part) {
4714 SmallVector<Value *, 4> Args;
4715 for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
4716 Value *Arg = CI->getArgOperand(i);
4717 // Some intrinsics have a scalar argument - don't replace it with a
4718 // vector.
4719 if (!UseVectorIntrinsic || !hasVectorInstrinsicScalarOpd(ID, i))
4720 Arg = getOrCreateVectorValue(CI->getArgOperand(i), Part);
4721 Args.push_back(Arg);
4722 }
4723
4724 Function *VectorF;
4725 if (UseVectorIntrinsic) {
4726 // Use vector version of the intrinsic.
4727 Type *TysForDecl[] = {CI->getType()};
4728 if (VF > 1)
4729 TysForDecl[0] = VectorType::get(CI->getType()->getScalarType(), VF);
4730 VectorF = Intrinsic::getDeclaration(M, ID, TysForDecl);
4731 } else {
4732 // Use vector version of the library call.
4733 StringRef VFnName = TLI->getVectorizedFunction(FnName, VF);
4734 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4734, __extension__ __PRETTY_FUNCTION__))
;
4735 VectorF = M->getFunction(VFnName);
4736 if (!VectorF) {
4737 // Generate a declaration
4738 FunctionType *FTy = FunctionType::get(RetTy, Tys, false);
4739 VectorF =
4740 Function::Create(FTy, Function::ExternalLinkage, VFnName, M);
4741 VectorF->copyAttributesFrom(F);
4742 }
4743 }
4744 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4744, __extension__ __PRETTY_FUNCTION__))
;
4745
4746 SmallVector<OperandBundleDef, 1> OpBundles;
4747 CI->getOperandBundlesAsDefs(OpBundles);
4748 CallInst *V = Builder.CreateCall(VectorF, Args, OpBundles);
4749
4750 if (isa<FPMathOperator>(V))
4751 V->copyFastMathFlags(CI);
4752
4753 VectorLoopValueMap.setVectorValue(&I, Part, V);
4754 addMetadata(V, &I);
4755 }
4756
4757 break;
4758 }
4759
4760 default:
4761 // This instruction is not vectorized by simple widening.
4762 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)
;
4763 llvm_unreachable("Unhandled instruction!")::llvm::llvm_unreachable_internal("Unhandled instruction!", "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4763)
;
4764 } // end of switch.
4765}
4766
4767void InnerLoopVectorizer::updateAnalysis() {
4768 // Forget the original basic block.
4769 PSE.getSE()->forgetLoop(OrigLoop);
4770
4771 // Update the dominator tree information.
4772 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4773, __extension__ __PRETTY_FUNCTION__))
4773 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4773, __extension__ __PRETTY_FUNCTION__))
;
4774
4775 DT->addNewBlock(LoopMiddleBlock,
4776 LI->getLoopFor(LoopVectorBody)->getLoopLatch());
4777 DT->addNewBlock(LoopScalarPreHeader, LoopBypassBlocks[0]);
4778 DT->changeImmediateDominator(LoopScalarBody, LoopScalarPreHeader);
4779 DT->changeImmediateDominator(LoopExitBlock, LoopBypassBlocks[0]);
4780 DEBUG(DT->verifyDomTree())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { DT->verifyDomTree(); } } while (false
)
;
4781}
4782
4783/// \brief Check whether it is safe to if-convert this phi node.
4784///
4785/// Phi nodes with constant expressions that can trap are not safe to if
4786/// convert.
4787static bool canIfConvertPHINodes(BasicBlock *BB) {
4788 for (PHINode &Phi : BB->phis()) {
4789 for (Value *V : Phi.incoming_values())
4790 if (auto *C = dyn_cast<Constant>(V))
4791 if (C->canTrap())
4792 return false;
4793 }
4794 return true;
4795}
4796
4797bool LoopVectorizationLegality::canVectorizeWithIfConvert() {
4798 if (!EnableIfConversion) {
4799 ORE->emit(createMissedAnalysis("IfConversionDisabled")
4800 << "if-conversion is disabled");
4801 return false;
4802 }
4803
4804 assert(TheLoop->getNumBlocks() > 1 && "Single block loops are vectorizable")(static_cast <bool> (TheLoop->getNumBlocks() > 1 &&
"Single block loops are vectorizable") ? void (0) : __assert_fail
("TheLoop->getNumBlocks() > 1 && \"Single block loops are vectorizable\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 4804, __extension__ __PRETTY_FUNCTION__))
;
4805
4806 // A list of pointers that we can safely read and write to.
4807 SmallPtrSet<Value *, 8> SafePointes;
4808
4809 // Collect safe addresses.
4810 for (BasicBlock *BB : TheLoop->blocks()) {
4811 if (blockNeedsPredication(BB))
4812 continue;
4813
4814 for (Instruction &I : *BB)
4815 if (auto *Ptr = getPointerOperand(&I))
4816 SafePointes.insert(Ptr);
4817 }
4818
4819 // Collect the blocks that need predication.
4820 BasicBlock *Header = TheLoop->getHeader();
4821 for (BasicBlock *BB : TheLoop->blocks()) {
4822 // We don't support switch statements inside loops.
4823 if (!isa<BranchInst>(BB->getTerminator())) {
4824 ORE->emit(createMissedAnalysis("LoopContainsSwitch", BB->getTerminator())
4825 << "loop contains a switch statement");
4826 return false;
4827 }
4828
4829 // We must be able to predicate all blocks that need to be predicated.
4830 if (blockNeedsPredication(BB)) {
4831 if (!blockCanBePredicated(BB, SafePointes)) {
4832 ORE->emit(createMissedAnalysis("NoCFGForSelect", BB->getTerminator())
4833 << "control flow cannot be substituted for a select");
4834 return false;
4835 }
4836 } else if (BB != Header && !canIfConvertPHINodes(BB)) {
4837 ORE->emit(createMissedAnalysis("NoCFGForSelect", BB->getTerminator())
4838 << "control flow cannot be substituted for a select");
4839 return false;
4840 }
4841 }
4842
4843 // We can if-convert this loop.
4844 return true;
4845}
4846
4847bool LoopVectorizationLegality::canVectorize() {
4848 // Store the result and return it at the end instead of exiting early, in case
4849 // allowExtraAnalysis is used to report multiple reasons for not vectorizing.
4850 bool Result = true;
4851
4852 bool DoExtraAnalysis = ORE->allowExtraAnalysis(DEBUG_TYPE"loop-vectorize");
4853 // We must have a loop in canonical form. Loops with indirectbr in them cannot
4854 // be canonicalized.
4855 if (!TheLoop->getLoopPreheader()) {
4856 DEBUG(dbgs() << "LV: Loop doesn't have a legal pre-header.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop doesn't have a legal pre-header.\n"
; } } while (false)
;
4857 ORE->emit(createMissedAnalysis("CFGNotUnderstood")
4858 << "loop control flow is not understood by vectorizer");
4859 if (DoExtraAnalysis)
4860 Result = false;
4861 else
4862 return false;
4863 }
4864
4865 // FIXME: The code is currently dead, since the loop gets sent to
4866 // LoopVectorizationLegality is already an innermost loop.
4867 //
4868 // We can only vectorize innermost loops.
4869 if (!TheLoop->empty()) {
4870 ORE->emit(createMissedAnalysis("NotInnermostLoop")
4871 << "loop is not the innermost loop");
4872 if (DoExtraAnalysis)
4873 Result = false;
4874 else
4875 return false;
4876 }
4877
4878 // We must have a single backedge.
4879 if (TheLoop->getNumBackEdges() != 1) {
4880 ORE->emit(createMissedAnalysis("CFGNotUnderstood")
4881 << "loop control flow is not understood by vectorizer");
4882 if (DoExtraAnalysis)
4883 Result = false;
4884 else
4885 return false;
4886 }
4887
4888 // We must have a single exiting block.
4889 if (!TheLoop->getExitingBlock()) {
4890 ORE->emit(createMissedAnalysis("CFGNotUnderstood")
4891 << "loop control flow is not understood by vectorizer");
4892 if (DoExtraAnalysis)
4893 Result = false;
4894 else
4895 return false;
4896 }
4897
4898 // We only handle bottom-tested loops, i.e. loop in which the condition is
4899 // checked at the end of each iteration. With that we can assume that all
4900 // instructions in the loop are executed the same number of times.
4901 if (TheLoop->getExitingBlock() != TheLoop->getLoopLatch()) {
4902 ORE->emit(createMissedAnalysis("CFGNotUnderstood")
4903 << "loop control flow is not understood by vectorizer");
4904 if (DoExtraAnalysis)
4905 Result = false;
4906 else
4907 return false;
4908 }
4909
4910 // We need to have a loop header.
4911 DEBUG(dbgs() << "LV: Found a loop: " << TheLoop->getHeader()->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a loop: " <<
TheLoop->getHeader()->getName() << '\n'; } } while
(false)
4912 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a loop: " <<
TheLoop->getHeader()->getName() << '\n'; } } while
(false)
;
4913
4914 // Check if we can if-convert non-single-bb loops.
4915 unsigned NumBlocks = TheLoop->getNumBlocks();
4916 if (NumBlocks != 1 && !canVectorizeWithIfConvert()) {
4917 DEBUG(dbgs() << "LV: Can't if-convert the loop.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Can't if-convert the loop.\n"
; } } while (false)
;
4918 if (DoExtraAnalysis)
4919 Result = false;
4920 else
4921 return false;
4922 }
4923
4924 // Check if we can vectorize the instructions and CFG in this loop.
4925 if (!canVectorizeInstrs()) {
4926 DEBUG(dbgs() << "LV: Can't vectorize the instructions or CFG\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Can't vectorize the instructions or CFG\n"
; } } while (false)
;
4927 if (DoExtraAnalysis)
4928 Result = false;
4929 else
4930 return false;
4931 }
4932
4933 // Go over each instruction and look at memory deps.
4934 if (!canVectorizeMemory()) {
4935 DEBUG(dbgs() << "LV: Can't vectorize due to memory conflicts\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Can't vectorize due to memory conflicts\n"
; } } while (false)
;
4936 if (DoExtraAnalysis)
4937 Result = false;
4938 else
4939 return false;
4940 }
4941
4942 DEBUG(dbgs() << "LV: We can vectorize this loop"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: We can vectorize this loop"
<< (LAI->getRuntimePointerChecking()->Need ? " (with a runtime bound check)"
: "") << "!\n"; } } while (false)
4943 << (LAI->getRuntimePointerChecking()->Needdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: We can vectorize this loop"
<< (LAI->getRuntimePointerChecking()->Need ? " (with a runtime bound check)"
: "") << "!\n"; } } while (false)
4944 ? " (with a runtime bound check)"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: We can vectorize this loop"
<< (LAI->getRuntimePointerChecking()->Need ? " (with a runtime bound check)"
: "") << "!\n"; } } while (false)
4945 : "")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: We can vectorize this loop"
<< (LAI->getRuntimePointerChecking()->Need ? " (with a runtime bound check)"
: "") << "!\n"; } } while (false)
4946 << "!\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: We can vectorize this loop"
<< (LAI->getRuntimePointerChecking()->Need ? " (with a runtime bound check)"
: "") << "!\n"; } } while (false)
;
4947
4948 bool UseInterleaved = TTI->enableInterleavedAccessVectorization();
4949
4950 // If an override option has been passed in for interleaved accesses, use it.
4951 if (EnableInterleavedMemAccesses.getNumOccurrences() > 0)
4952 UseInterleaved = EnableInterleavedMemAccesses;
4953
4954 // Analyze interleaved memory accesses.
4955 if (UseInterleaved)
4956 InterleaveInfo.analyzeInterleaving(*getSymbolicStrides());
4957
4958 unsigned SCEVThreshold = VectorizeSCEVCheckThreshold;
4959 if (Hints->getForce() == LoopVectorizeHints::FK_Enabled)
4960 SCEVThreshold = PragmaVectorizeSCEVCheckThreshold;
4961
4962 if (PSE.getUnionPredicate().getComplexity() > SCEVThreshold) {
4963 ORE->emit(createMissedAnalysis("TooManySCEVRunTimeChecks")
4964 << "Too many SCEV assumptions need to be made and checked "
4965 << "at runtime");
4966 DEBUG(dbgs() << "LV: Too many SCEV checks needed.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Too many SCEV checks needed.\n"
; } } while (false)
;
4967 if (DoExtraAnalysis)
4968 Result = false;
4969 else
4970 return false;
4971 }
4972
4973 // Okay! We've done all the tests. If any have failed, return false. Otherwise
4974 // we can vectorize, and at this point we don't have any other mem analysis
4975 // which may limit our maximum vectorization factor, so just return true with
4976 // no restrictions.
4977 return Result;
4978}
4979
4980static Type *convertPointerToIntegerType(const DataLayout &DL, Type *Ty) {
4981 if (Ty->isPointerTy())
4982 return DL.getIntPtrType(Ty);
4983
4984 // It is possible that char's or short's overflow when we ask for the loop's
4985 // trip count, work around this by changing the type size.
4986 if (Ty->getScalarSizeInBits() < 32)
4987 return Type::getInt32Ty(Ty->getContext());
4988
4989 return Ty;
4990}
4991
4992static Type *getWiderType(const DataLayout &DL, Type *Ty0, Type *Ty1) {
4993 Ty0 = convertPointerToIntegerType(DL, Ty0);
4994 Ty1 = convertPointerToIntegerType(DL, Ty1);
4995 if (Ty0->getScalarSizeInBits() > Ty1->getScalarSizeInBits())
4996 return Ty0;
4997 return Ty1;
4998}
4999
5000/// \brief Check that the instruction has outside loop users and is not an
5001/// identified reduction variable.
5002static bool hasOutsideLoopUser(const Loop *TheLoop, Instruction *Inst,
5003 SmallPtrSetImpl<Value *> &AllowedExit) {
5004 // Reduction and Induction instructions are allowed to have exit users. All
5005 // other instructions must not have external users.
5006 if (!AllowedExit.count(Inst))
5007 // Check that all of the users of the loop are inside the BB.
5008 for (User *U : Inst->users()) {
5009 Instruction *UI = cast<Instruction>(U);
5010 // This user may be a reduction exit value.
5011 if (!TheLoop->contains(UI)) {
5012 DEBUG(dbgs() << "LV: Found an outside user for : " << *UI << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an outside user for : "
<< *UI << '\n'; } } while (false)
;
5013 return true;
5014 }
5015 }
5016 return false;
5017}
5018
5019void LoopVectorizationLegality::addInductionPhi(
5020 PHINode *Phi, const InductionDescriptor &ID,
5021 SmallPtrSetImpl<Value *> &AllowedExit) {
5022 Inductions[Phi] = ID;
5023
5024 // In case this induction also comes with casts that we know we can ignore
5025 // in the vectorized loop body, record them here. All casts could be recorded
5026 // here for ignoring, but suffices to record only the first (as it is the
5027 // only one that may bw used outside the cast sequence).
5028 const SmallVectorImpl<Instruction *> &Casts = ID.getCastInsts();
5029 if (!Casts.empty())
5030 InductionCastsToIgnore.insert(*Casts.begin());
5031
5032 Type *PhiTy = Phi->getType();
5033 const DataLayout &DL = Phi->getModule()->getDataLayout();
5034
5035 // Get the widest type.
5036 if (!PhiTy->isFloatingPointTy()) {
5037 if (!WidestIndTy)
5038 WidestIndTy = convertPointerToIntegerType(DL, PhiTy);
5039 else
5040 WidestIndTy = getWiderType(DL, PhiTy, WidestIndTy);
5041 }
5042
5043 // Int inductions are special because we only allow one IV.
5044 if (ID.getKind() == InductionDescriptor::IK_IntInduction &&
5045 ID.getConstIntStepValue() &&
5046 ID.getConstIntStepValue()->isOne() &&
5047 isa<Constant>(ID.getStartValue()) &&
5048 cast<Constant>(ID.getStartValue())->isNullValue()) {
5049
5050 // Use the phi node with the widest type as induction. Use the last
5051 // one if there are multiple (no good reason for doing this other
5052 // than it is expedient). We've checked that it begins at zero and
5053 // steps by one, so this is a canonical induction variable.
5054 if (!PrimaryInduction || PhiTy == WidestIndTy)
5055 PrimaryInduction = Phi;
5056 }
5057
5058 // Both the PHI node itself, and the "post-increment" value feeding
5059 // back into the PHI node may have external users.
5060 // We can allow those uses, except if the SCEVs we have for them rely
5061 // on predicates that only hold within the loop, since allowing the exit
5062 // currently means re-using this SCEV outside the loop.
5063 if (PSE.getUnionPredicate().isAlwaysTrue()) {
5064 AllowedExit.insert(Phi);
5065 AllowedExit.insert(Phi->getIncomingValueForBlock(TheLoop->getLoopLatch()));
5066 }
5067
5068 DEBUG(dbgs() << "LV: Found an induction variable.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an induction variable.\n"
; } } while (false)
;
5069}
5070
5071bool LoopVectorizationLegality::canVectorizeInstrs() {
5072 BasicBlock *Header = TheLoop->getHeader();
5073
5074 // Look for the attribute signaling the absence of NaNs.
5075 Function &F = *Header->getParent();
5076 HasFunNoNaNAttr =
5077 F.getFnAttribute("no-nans-fp-math").getValueAsString() == "true";
5078
5079 // For each block in the loop.
5080 for (BasicBlock *BB : TheLoop->blocks()) {
5081 // Scan the instructions in the block and look for hazards.
5082 for (Instruction &I : *BB) {
5083 if (auto *Phi = dyn_cast<PHINode>(&I)) {
5084 Type *PhiTy = Phi->getType();
5085 // Check that this PHI type is allowed.
5086 if (!PhiTy->isIntegerTy() && !PhiTy->isFloatingPointTy() &&
5087 !PhiTy->isPointerTy()) {
5088 ORE->emit(createMissedAnalysis("CFGNotUnderstood", Phi)
5089 << "loop control flow is not understood by vectorizer");
5090 DEBUG(dbgs() << "LV: Found an non-int non-pointer PHI.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an non-int non-pointer PHI.\n"
; } } while (false)
;
5091 return false;
5092 }
5093
5094 // If this PHINode is not in the header block, then we know that we
5095 // can convert it to select during if-conversion. No need to check if
5096 // the PHIs in this block are induction or reduction variables.
5097 if (BB != Header) {
5098 // Check that this instruction has no outside users or is an
5099 // identified reduction value with an outside user.
5100 if (!hasOutsideLoopUser(TheLoop, Phi, AllowedExit))
5101 continue;
5102 ORE->emit(createMissedAnalysis("NeitherInductionNorReduction", Phi)
5103 << "value could not be identified as "
5104 "an induction or reduction variable");
5105 return false;
5106 }
5107
5108 // We only allow if-converted PHIs with exactly two incoming values.
5109 if (Phi->getNumIncomingValues() != 2) {
5110 ORE->emit(createMissedAnalysis("CFGNotUnderstood", Phi)
5111 << "control flow not understood by vectorizer");
5112 DEBUG(dbgs() << "LV: Found an invalid PHI.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an invalid PHI.\n"
; } } while (false)
;
5113 return false;
5114 }
5115
5116 RecurrenceDescriptor RedDes;
5117 if (RecurrenceDescriptor::isReductionPHI(Phi, TheLoop, RedDes, DB, AC,
5118 DT)) {
5119 if (RedDes.hasUnsafeAlgebra())
5120 Requirements->addUnsafeAlgebraInst(RedDes.getUnsafeAlgebraInst());
5121 AllowedExit.insert(RedDes.getLoopExitInstr());
5122 Reductions[Phi] = RedDes;
5123 continue;
5124 }
5125
5126 InductionDescriptor ID;
5127 if (InductionDescriptor::isInductionPHI(Phi, TheLoop, PSE, ID)) {
5128 addInductionPhi(Phi, ID, AllowedExit);
5129 if (ID.hasUnsafeAlgebra() && !HasFunNoNaNAttr)
5130 Requirements->addUnsafeAlgebraInst(ID.getUnsafeAlgebraInst());
5131 continue;
5132 }
5133
5134 if (RecurrenceDescriptor::isFirstOrderRecurrence(Phi, TheLoop,
5135 SinkAfter, DT)) {
5136 FirstOrderRecurrences.insert(Phi);
5137 continue;
5138 }
5139
5140 // As a last resort, coerce the PHI to a AddRec expression
5141 // and re-try classifying it a an induction PHI.
5142 if (InductionDescriptor::isInductionPHI(Phi, TheLoop, PSE, ID, true)) {
5143 addInductionPhi(Phi, ID, AllowedExit);
5144 continue;
5145 }
5146
5147 ORE->emit(createMissedAnalysis("NonReductionValueUsedOutsideLoop", Phi)
5148 << "value that could not be identified as "
5149 "reduction is used outside the loop");
5150 DEBUG(dbgs() << "LV: Found an unidentified PHI." << *Phi << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an unidentified PHI."
<< *Phi << "\n"; } } while (false)
;
5151 return false;
5152 } // end of PHI handling
5153
5154 // We handle calls that:
5155 // * Are debug info intrinsics.
5156 // * Have a mapping to an IR intrinsic.
5157 // * Have a vector version available.
5158 auto *CI = dyn_cast<CallInst>(&I);
5159 if (CI && !getVectorIntrinsicIDForCall(CI, TLI) &&
5160 !isa<DbgInfoIntrinsic>(CI) &&
5161 !(CI->getCalledFunction() && TLI &&
5162 TLI->isFunctionVectorizable(CI->getCalledFunction()->getName()))) {
5163 ORE->emit(createMissedAnalysis("CantVectorizeCall", CI)
5164 << "call instruction cannot be vectorized");
5165 DEBUG(dbgs() << "LV: Found a non-intrinsic, non-libfunc callsite.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a non-intrinsic, non-libfunc callsite.\n"
; } } while (false)
;
5166 return false;
5167 }
5168
5169 // Intrinsics such as powi,cttz and ctlz are legal to vectorize if the
5170 // second argument is the same (i.e. loop invariant)
5171 if (CI && hasVectorInstrinsicScalarOpd(
5172 getVectorIntrinsicIDForCall(CI, TLI), 1)) {
5173 auto *SE = PSE.getSE();
5174 if (!SE->isLoopInvariant(PSE.getSCEV(CI->getOperand(1)), TheLoop)) {
5175 ORE->emit(createMissedAnalysis("CantVectorizeIntrinsic", CI)
5176 << "intrinsic instruction cannot be vectorized");
5177 DEBUG(dbgs() << "LV: Found unvectorizable intrinsic " << *CI << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found unvectorizable intrinsic "
<< *CI << "\n"; } } while (false)
;
5178 return false;
5179 }
5180 }
5181
5182 // Check that the instruction return type is vectorizable.
5183 // Also, we can't vectorize extractelement instructions.
5184 if ((!VectorType::isValidElementType(I.getType()) &&
5185 !I.getType()->isVoidTy()) ||
5186 isa<ExtractElementInst>(I)) {
5187 ORE->emit(createMissedAnalysis("CantVectorizeInstructionReturnType", &I)
5188 << "instruction return type cannot be vectorized");
5189 DEBUG(dbgs() << "LV: Found unvectorizable type.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found unvectorizable type.\n"
; } } while (false)
;
5190 return false;
5191 }
5192
5193 // Check that the stored type is vectorizable.
5194 if (auto *ST = dyn_cast<StoreInst>(&I)) {
5195 Type *T = ST->getValueOperand()->getType();
5196 if (!VectorType::isValidElementType(T)) {
5197 ORE->emit(createMissedAnalysis("CantVectorizeStore", ST)
5198 << "store instruction cannot be vectorized");
5199 return false;
5200 }
5201
5202 // FP instructions can allow unsafe algebra, thus vectorizable by
5203 // non-IEEE-754 compliant SIMD units.
5204 // This applies to floating-point math operations and calls, not memory
5205 // operations, shuffles, or casts, as they don't change precision or
5206 // semantics.
5207 } else if (I.getType()->isFloatingPointTy() && (CI || I.isBinaryOp()) &&
5208 !I.isFast()) {
5209 DEBUG(dbgs() << "LV: Found FP op with unsafe algebra.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found FP op with unsafe algebra.\n"
; } } while (false)
;
5210 Hints->setPotentiallyUnsafe();
5211 }
5212
5213 // Reduction instructions are allowed to have exit users.
5214 // All other instructions must not have external users.
5215 if (hasOutsideLoopUser(TheLoop, &I, AllowedExit)) {
5216 ORE->emit(createMissedAnalysis("ValueUsedOutsideLoop", &I)
5217 << "value cannot be used outside the loop");
5218 return false;
5219 }
5220 } // next instr.
5221 }
5222
5223 if (!PrimaryInduction) {
5224 DEBUG(dbgs() << "LV: Did not find one integer induction var.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Did not find one integer induction var.\n"
; } } while (false)
;
5225 if (Inductions.empty()) {
5226 ORE->emit(createMissedAnalysis("NoInductionVariable")
5227 << "loop induction variable could not be identified");
5228 return false;
5229 }
5230 }
5231
5232 // Now we know the widest induction type, check if our found induction
5233 // is the same size. If it's not, unset it here and InnerLoopVectorizer
5234 // will create another.
5235 if (PrimaryInduction && WidestIndTy != PrimaryInduction->getType())
5236 PrimaryInduction = nullptr;
5237
5238 return true;
5239}
5240
5241void LoopVectorizationCostModel::collectLoopScalars(unsigned VF) {
5242 // We should not collect Scalars more than once per VF. Right now, this
5243 // function is called from collectUniformsAndScalars(), which already does
5244 // this check. Collecting Scalars for VF=1 does not make any sense.
5245 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5246, __extension__ __PRETTY_FUNCTION__))
5246 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5246, __extension__ __PRETTY_FUNCTION__))
;
5247
5248 SmallSetVector<Instruction *, 8> Worklist;
5249
5250 // These sets are used to seed the analysis with pointers used by memory
5251 // accesses that will remain scalar.
5252 SmallSetVector<Instruction *, 8> ScalarPtrs;
5253 SmallPtrSet<Instruction *, 8> PossibleNonScalarPtrs;
5254
5255 // A helper that returns true if the use of Ptr by MemAccess will be scalar.
5256 // The pointer operands of loads and stores will be scalar as long as the
5257 // memory access is not a gather or scatter operation. The value operand of a
5258 // store will remain scalar if the store is scalarized.
5259 auto isScalarUse = [&](Instruction *MemAccess, Value *Ptr) {
5260 InstWidening WideningDecision = getWideningDecision(MemAccess, VF);
5261 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5262, __extension__ __PRETTY_FUNCTION__))
5262 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5262, __extension__ __PRETTY_FUNCTION__))
;
5263 if (auto *Store = dyn_cast<StoreInst>(MemAccess))
5264 if (Ptr == Store->getValueOperand())
5265 return WideningDecision == CM_Scalarize;
5266 assert(Ptr == getPointerOperand(MemAccess) &&(static_cast <bool> (Ptr == getPointerOperand(MemAccess
) && "Ptr is neither a value or pointer operand") ? void
(0) : __assert_fail ("Ptr == getPointerOperand(MemAccess) && \"Ptr is neither a value or pointer operand\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5267, __extension__ __PRETTY_FUNCTION__))
5267 "Ptr is neither a value or pointer operand")(static_cast <bool> (Ptr == getPointerOperand(MemAccess
) && "Ptr is neither a value or pointer operand") ? void
(0) : __assert_fail ("Ptr == getPointerOperand(MemAccess) && \"Ptr is neither a value or pointer operand\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5267, __extension__ __PRETTY_FUNCTION__))
;
5268 return WideningDecision != CM_GatherScatter;
5269 };
5270
5271 // A helper that returns true if the given value is a bitcast or
5272 // getelementptr instruction contained in the loop.
5273 auto isLoopVaryingBitCastOrGEP = [&](Value *V) {
5274 return ((isa<BitCastInst>(V) && V->getType()->isPointerTy()) ||
5275 isa<GetElementPtrInst>(V)) &&
5276 !TheLoop->isLoopInvariant(V);
5277 };
5278
5279 // A helper that evaluates a memory access's use of a pointer. If the use
5280 // will be a scalar use, and the pointer is only used by memory accesses, we
5281 // place the pointer in ScalarPtrs. Otherwise, the pointer is placed in
5282 // PossibleNonScalarPtrs.
5283 auto evaluatePtrUse = [&](Instruction *MemAccess, Value *Ptr) {
5284 // We only care about bitcast and getelementptr instructions contained in
5285 // the loop.
5286 if (!isLoopVaryingBitCastOrGEP(Ptr))
5287 return;
5288
5289 // If the pointer has already been identified as scalar (e.g., if it was
5290 // also identified as uniform), there's nothing to do.
5291 auto *I = cast<Instruction>(Ptr);
5292 if (Worklist.count(I))
5293 return;
5294
5295 // If the use of the pointer will be a scalar use, and all users of the
5296 // pointer are memory accesses, place the pointer in ScalarPtrs. Otherwise,
5297 // place the pointer in PossibleNonScalarPtrs.
5298 if (isScalarUse(MemAccess, Ptr) && llvm::all_of(I->users(), [&](User *U) {
5299 return isa<LoadInst>(U) || isa<StoreInst>(U);
5300 }))
5301 ScalarPtrs.insert(I);
5302 else
5303 PossibleNonScalarPtrs.insert(I);
5304 };
5305
5306 // We seed the scalars analysis with three classes of instructions: (1)
5307 // instructions marked uniform-after-vectorization, (2) bitcast and
5308 // getelementptr instructions used by memory accesses requiring a scalar use,
5309 // and (3) pointer induction variables and their update instructions (we
5310 // currently only scalarize these).
5311 //
5312 // (1) Add to the worklist all instructions that have been identified as
5313 // uniform-after-vectorization.
5314 Worklist.insert(Uniforms[VF].begin(), Uniforms[VF].end());
5315
5316 // (2) Add to the worklist all bitcast and getelementptr instructions used by
5317 // memory accesses requiring a scalar use. The pointer operands of loads and
5318 // stores will be scalar as long as the memory accesses is not a gather or
5319 // scatter operation. The value operand of a store will remain scalar if the
5320 // store is scalarized.
5321 for (auto *BB : TheLoop->blocks())
5322 for (auto &I : *BB) {
5323 if (auto *Load = dyn_cast<LoadInst>(&I)) {
5324 evaluatePtrUse(Load, Load->getPointerOperand());
5325 } else if (auto *Store = dyn_cast<StoreInst>(&I)) {
5326 evaluatePtrUse(Store, Store->getPointerOperand());
5327 evaluatePtrUse(Store, Store->getValueOperand());
5328 }
5329 }
5330 for (auto *I : ScalarPtrs)
5331 if (!PossibleNonScalarPtrs.count(I)) {
5332 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)
;
5333 Worklist.insert(I);
5334 }
5335
5336 // (3) Add to the worklist all pointer induction variables and their update
5337 // instructions.
5338 //
5339 // TODO: Once we are able to vectorize pointer induction variables we should
5340 // no longer insert them into the worklist here.
5341 auto *Latch = TheLoop->getLoopLatch();
5342 for (auto &Induction : *Legal->getInductionVars()) {
5343 auto *Ind = Induction.first;
5344 auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch));
5345 if (Induction.second.getKind() != InductionDescriptor::IK_PtrInduction)
5346 continue;
5347 Worklist.insert(Ind);
5348 Worklist.insert(IndUpdate);
5349 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)
;
5350 DEBUG(dbgs() << "LV: Found scalar instruction: " << *IndUpdate << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *IndUpdate << "\n"; } } while (false)
;
5351 }
5352
5353 // Insert the forced scalars.
5354 // FIXME: Currently widenPHIInstruction() often creates a dead vector
5355 // induction variable when the PHI user is scalarized.
5356 if (ForcedScalars.count(VF))
5357 for (auto *I : ForcedScalars.find(VF)->second)
5358 Worklist.insert(I);
5359
5360 // Expand the worklist by looking through any bitcasts and getelementptr
5361 // instructions we've already identified as scalar. This is similar to the
5362 // expansion step in collectLoopUniforms(); however, here we're only
5363 // expanding to include additional bitcasts and getelementptr instructions.
5364 unsigned Idx = 0;
5365 while (Idx != Worklist.size()) {
5366 Instruction *Dst = Worklist[Idx++];
5367 if (!isLoopVaryingBitCastOrGEP(Dst->getOperand(0)))
5368 continue;
5369 auto *Src = cast<Instruction>(Dst->getOperand(0));
5370 if (llvm::all_of(Src->users(), [&](User *U) -> bool {
5371 auto *J = cast<Instruction>(U);
5372 return !TheLoop->contains(J) || Worklist.count(J) ||
5373 ((isa<LoadInst>(J) || isa<StoreInst>(J)) &&
5374 isScalarUse(J, Src));
5375 })) {
5376 Worklist.insert(Src);
5377 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)
;
5378 }
5379 }
5380
5381 // An induction variable will remain scalar if all users of the induction
5382 // variable and induction variable update remain scalar.
5383 for (auto &Induction : *Legal->getInductionVars()) {
5384 auto *Ind = Induction.first;
5385 auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch));
5386
5387 // We already considered pointer induction variables, so there's no reason
5388 // to look at their users again.
5389 //
5390 // TODO: Once we are able to vectorize pointer induction variables we
5391 // should no longer skip over them here.
5392 if (Induction.second.getKind() == InductionDescriptor::IK_PtrInduction)
5393 continue;
5394
5395 // Determine if all users of the induction variable are scalar after
5396 // vectorization.
5397 auto ScalarInd = llvm::all_of(Ind->users(), [&](User *U) -> bool {
5398 auto *I = cast<Instruction>(U);
5399 return I == IndUpdate || !TheLoop->contains(I) || Worklist.count(I);
5400 });
5401 if (!ScalarInd)
5402 continue;
5403
5404 // Determine if all users of the induction variable update instruction are
5405 // scalar after vectorization.
5406 auto ScalarIndUpdate =
5407 llvm::all_of(IndUpdate->users(), [&](User *U) -> bool {
5408 auto *I = cast<Instruction>(U);
5409 return I == Ind || !TheLoop->contains(I) || Worklist.count(I);
5410 });
5411 if (!ScalarIndUpdate)
5412 continue;
5413
5414 // The induction variable and its update instruction will remain scalar.
5415 Worklist.insert(Ind);
5416 Worklist.insert(IndUpdate);
5417 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)
;
5418 DEBUG(dbgs() << "LV: Found scalar instruction: " << *IndUpdate << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found scalar instruction: "
<< *IndUpdate << "\n"; } } while (false)
;
5419 }
5420
5421 Scalars[VF].insert(Worklist.begin(), Worklist.end());
5422}
5423
5424bool LoopVectorizationLegality::isScalarWithPredication(Instruction *I) {
5425 if (!blockNeedsPredication(I->getParent()))
5426 return false;
5427 switch(I->getOpcode()) {
5428 default:
5429 break;
5430 case Instruction::Store:
5431 return !isMaskRequired(I);
5432 case Instruction::UDiv:
5433 case Instruction::SDiv:
5434 case Instruction::SRem:
5435 case Instruction::URem:
5436 return mayDivideByZero(*I);
5437 }
5438 return false;
5439}
5440
5441bool LoopVectorizationLegality::memoryInstructionCanBeWidened(Instruction *I,
5442 unsigned VF) {
5443 // Get and ensure we have a valid memory instruction.
5444 LoadInst *LI = dyn_cast<LoadInst>(I);
5445 StoreInst *SI = dyn_cast<StoreInst>(I);
5446 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5446, __extension__ __PRETTY_FUNCTION__))
;
5447
5448 auto *Ptr = getPointerOperand(I);
5449
5450 // In order to be widened, the pointer should be consecutive, first of all.
5451 if (!isConsecutivePtr(Ptr))
5452 return false;
5453
5454 // If the instruction is a store located in a predicated block, it will be
5455 // scalarized.
5456 if (isScalarWithPredication(I))
5457 return false;
5458
5459 // If the instruction's allocated size doesn't equal it's type size, it
5460 // requires padding and will be scalarized.
5461 auto &DL = I->getModule()->getDataLayout();
5462 auto *ScalarTy = LI ? LI->getType() : SI->getValueOperand()->getType();
5463 if (hasIrregularType(ScalarTy, DL, VF))
5464 return false;
5465
5466 return true;
5467}
5468
5469void LoopVectorizationCostModel::collectLoopUniforms(unsigned VF) {
5470 // We should not collect Uniforms more than once per VF. Right now,
5471 // this function is called from collectUniformsAndScalars(), which
5472 // already does this check. Collecting Uniforms for VF=1 does not make any
5473 // sense.
5474
5475 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5476, __extension__ __PRETTY_FUNCTION__))
5476 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5476, __extension__ __PRETTY_FUNCTION__))
;
5477
5478 // Visit the list of Uniforms. If we'll not find any uniform value, we'll
5479 // not analyze again. Uniforms.count(VF) will return 1.
5480 Uniforms[VF].clear();
5481
5482 // We now know that the loop is vectorizable!
5483 // Collect instructions inside the loop that will remain uniform after
5484 // vectorization.
5485
5486 // Global values, params and instructions outside of current loop are out of
5487 // scope.
5488 auto isOutOfScope = [&](Value *V) -> bool {
5489 Instruction *I = dyn_cast<Instruction>(V);
5490 return (!I || !TheLoop->contains(I));
5491 };
5492
5493 SetVector<Instruction *> Worklist;
5494 BasicBlock *Latch = TheLoop->getLoopLatch();
5495
5496 // Start with the conditional branch. If the branch condition is an
5497 // instruction contained in the loop that is only used by the branch, it is
5498 // uniform.
5499 auto *Cmp = dyn_cast<Instruction>(Latch->getTerminator()->getOperand(0));
5500 if (Cmp && TheLoop->contains(Cmp) && Cmp->hasOneUse()) {
5501 Worklist.insert(Cmp);
5502 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)
;
5503 }
5504
5505 // Holds consecutive and consecutive-like pointers. Consecutive-like pointers
5506 // are pointers that are treated like consecutive pointers during
5507 // vectorization. The pointer operands of interleaved accesses are an
5508 // example.
5509 SmallSetVector<Instruction *, 8> ConsecutiveLikePtrs;
5510
5511 // Holds pointer operands of instructions that are possibly non-uniform.
5512 SmallPtrSet<Instruction *, 8> PossibleNonUniformPtrs;
5513
5514 auto isUniformDecision = [&](Instruction *I, unsigned VF) {
5515 InstWidening WideningDecision = getWideningDecision(I, VF);
5516 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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5517, __extension__ __PRETTY_FUNCTION__))
5517 "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~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 5517, __extension__ __PRETTY_FUNCTION__))
;
5518
5519 return (WideningDecision == CM_Widen ||
5520 WideningDecision == CM_Widen_Reverse ||
5521 WideningDecision == CM_Interleave);
5522 };
5523 // Iterate over the instructions in the loop, and collect all
5524 // consecutive-like pointer operands in ConsecutiveLikePtrs. If it's possible
5525 // that a consecutive-like pointer operand will be scalarized, we collect it
5526 // in PossibleNonUniformPtrs instead. We use two sets here because a single
5527 // getelementptr instruction can be used by both vectorized and scalarized
5528 // memory instructions. For example, if a loop loads and stores from the same
5529 // location, but the store is conditional, the store will be scalarized, and
5530 // the getelementptr won't remain uniform.
5531 for (auto *BB : TheLoop->blocks())
5532 for (auto &I : *BB) {
5533 // If there's no pointer operand, there's nothing to do.
5534 auto *Ptr = dyn_cast_or_null<Instruction>(getPointerOperand(&I));
5535 if (!Ptr)
5536 continue;
5537
5538 // True if all users of Ptr are memory accesses that have Ptr as their
5539 // pointer operand.
5540 auto UsersAreMemAccesses =
5541 llvm::all_of(Ptr->users(), [&](User *U) -> bool {
5542 return getPointerOperand(U) == Ptr;
5543 });
5544
5545 // Ensure the memory instruction will not be scalarized or used by
5546 // gather/scatter, making its pointer operand non-uniform. If the pointer
5547 // operand is used by any instruction other than a memory access, we
5548 // conservatively assume the pointer operand may be non-uniform.
5549 if (!UsersAreMemAccesses || !isUniformDecision(&I, VF))
5550 PossibleNonUniformPtrs.insert(Ptr);
5551
5552 // If the memory instruction will be vectorized and its pointer operand
5553 // is consecutive-like, or interleaving - the pointer operand should
5554 // remain uniform.
5555 else
5556 ConsecutiveLikePtrs.insert(Ptr);
5557 }
5558
5559 // Add to the Worklist all consecutive and consecutive-like pointers that
5560 // aren't also identified as possibly non-uniform.
5561 for (auto *V : ConsecutiveLikePtrs)
5562 if (!PossibleNonUniformPtrs.count(V)) {
5563 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)
;
5564 Worklist.insert(V);
5565 }
5566
5567 // Expand Worklist in topological order: whenever a new instruction
5568 // is added , its users should be either already inside Worklist, or
5569 // out of scope. It ensures a uniform instruction will only be used
5570 // by uniform instructions or out of scope instructions.
5571 unsigned idx = 0;
5572 while (idx != Worklist.size()) {
5573 Instruction *I = Worklist[idx++];
5574
5575 for (auto OV : I->operand_values()) {
5576 if (isOutOfScope(OV))
5577 continue;
5578 auto *OI = cast<Instruction>(OV);
5579 if (llvm::all_of(OI->users(), [&](User *U) -> bool {
5580 auto *J = cast<Instruction>(U);
5581 return !TheLoop->contains(J) || Worklist.count(J) ||
5582 (OI == getPointerOperand(J) && isUniformDecision(J, VF));
5583 })) {
5584 Worklist.insert(OI);
5585 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)
;
5586 }
5587 }
5588 }
5589
5590 // Returns true if Ptr is the pointer operand of a memory access instruction
5591 // I, and I is known to not require scalarization.
5592 auto isVectorizedMemAccessUse = [&](Instruction *I, Value *Ptr) -> bool {
5593 return getPointerOperand(I) == Ptr && isUniformDecision(I, VF);
5594 };
5595
5596 // For an instruction to be added into Worklist above, all its users inside
5597 // the loop should also be in Worklist. However, this condition cannot be
5598 // true for phi nodes that form a cyclic dependence. We must process phi
5599 // nodes separately. An induction variable will remain uniform if all users
5600 // of the induction variable and induction variable update remain uniform.
5601 // The code below handles both pointer and non-pointer induction variables.
5602 for (auto &Induction : *Legal->getInductionVars()) {
5603 auto *Ind = Induction.first;
5604 auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch));
5605
5606 // Determine if all users of the induction variable are uniform after
5607 // vectorization.
5608 auto UniformInd = llvm::all_of(Ind->users(), [&](User *U) -> bool {
5609 auto *I = cast<Instruction>(U);
5610 return I == IndUpdate || !TheLoop->contains(I) || Worklist.count(I) ||
5611 isVectorizedMemAccessUse(I, Ind);
5612 });
5613 if (!UniformInd)
5614 continue;
5615
5616 // Determine if all users of the induction variable update instruction are
5617 // uniform after vectorization.
5618 auto UniformIndUpdate =
5619 llvm::all_of(IndUpdate->users(), [&](User *U) -> bool {
5620 auto *I = cast<Instruction>(U);
5621 return I == Ind || !TheLoop->contains(I) || Worklist.count(I) ||
5622 isVectorizedMemAccessUse(I, IndUpdate);
5623 });
5624 if (!UniformIndUpdate)
5625 continue;
5626
5627 // The induction variable and its update instruction will remain uniform.
5628 Worklist.insert(Ind);
5629 Worklist.insert(IndUpdate);
5630 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)
;
5631 DEBUG(dbgs() << "LV: Found uniform instruction: " << *IndUpdate << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found uniform instruction: "
<< *IndUpdate << "\n"; } } while (false)
;
5632 }
5633
5634 Uniforms[VF].insert(Worklist.begin(), Worklist.end());
5635}
5636
5637bool LoopVectorizationLegality::canVectorizeMemory() {
5638 LAI = &(*GetLAA)(*TheLoop);
5639 InterleaveInfo.setLAI(LAI);
5640 const OptimizationRemarkAnalysis *LAR = LAI->getReport();
5641 if (LAR) {
5642 ORE->emit([&]() {
5643 return OptimizationRemarkAnalysis(Hints->vectorizeAnalysisPassName(),
5644 "loop not vectorized: ", *LAR);
5645 });
5646 }
5647 if (!LAI->canVectorizeMemory())
5648 return false;
5649
5650 if (LAI->hasStoreToLoopInvariantAddress()) {
5651 ORE->emit(createMissedAnalysis("CantVectorizeStoreToLoopInvariantAddress")
5652 << "write to a loop invariant address could not be vectorized");
5653 DEBUG(dbgs() << "LV: We don't allow storing to uniform addresses\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: We don't allow storing to uniform addresses\n"
; } } while (false)
;
5654 return false;
5655 }
5656
5657 Requirements->addRuntimePointerChecks(LAI->getNumRuntimePointerChecks());
5658 PSE.addPredicate(LAI->getPSE().getUnionPredicate());
5659
5660 return true;
5661}
5662
5663bool LoopVectorizationLegality::isInductionPhi(const Value *V) {
5664 Value *In0 = const_cast<Value *>(V);
5665 PHINode *PN = dyn_cast_or_null<PHINode>(In0);
5666 if (!PN)
5667 return false;
5668
5669 return Inductions.count(PN);
5670}
5671
5672bool LoopVectorizationLegality::isCastedInductionVariable(const Value *V) {
5673 auto *Inst = dyn_cast<Instruction>(V);
5674 return (Inst && InductionCastsToIgnore.count(Inst));
5675}
5676
5677bool LoopVectorizationLegality::isInductionVariable(const Value *V) {
5678 return isInductionPhi(V) || isCastedInductionVariable(V);
5679}
5680
5681bool LoopVectorizationLegality::isFirstOrderRecurrence(const PHINode *Phi) {
5682 return FirstOrderRecurrences.count(Phi);
5683}
5684
5685bool LoopVectorizationLegality::blockNeedsPredication(BasicBlock *BB) {
5686 return LoopAccessInfo::blockNeedsPredication(BB, TheLoop, DT);
5687}
5688
5689bool LoopVectorizationLegality::blockCanBePredicated(
5690 BasicBlock *BB, SmallPtrSetImpl<Value *> &SafePtrs) {
5691 const bool IsAnnotated