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 IsAnnotatedParallel = TheLoop->isAnnotatedParallel();
5692
5693 for (Instruction &I : *BB) {
5694 // Check that we don't have a constant expression that can trap as operand.
5695 for (Value *Operand : I.operands()) {
5696 if (auto *C = dyn_cast<Constant>(Operand))
5697 if (C->canTrap())
5698 return false;
5699 }
5700 // We might be able to hoist the load.
5701 if (I.mayReadFromMemory()) {
5702 auto *LI = dyn_cast<LoadInst>(&I);
5703 if (!LI)
5704 return false;
5705 if (!SafePtrs.count(LI->getPointerOperand())) {
5706 if (isLegalMaskedLoad(LI->getType(), LI->getPointerOperand()) ||
5707 isLegalMaskedGather(LI->getType())) {
5708 MaskedOp.insert(LI);
5709 continue;
5710 }
5711 // !llvm.mem.parallel_loop_access implies if-conversion safety.
5712 if (IsAnnotatedParallel)
5713 continue;
5714 return false;
5715 }
5716 }
5717
5718 if (I.mayWriteToMemory()) {
5719 auto *SI = dyn_cast<StoreInst>(&I);
5720 // We only support predication of stores in basic blocks with one
5721 // predecessor.
5722 if (!SI)
5723 return false;
5724
5725 // Build a masked store if it is legal for the target.
5726 if (isLegalMaskedStore(SI->getValueOperand()->getType(),
5727 SI->getPointerOperand()) ||
5728 isLegalMaskedScatter(SI->getValueOperand()->getType())) {
5729 MaskedOp.insert(SI);
5730 continue;
5731 }
5732
5733 bool isSafePtr = (SafePtrs.count(SI->getPointerOperand()) != 0);
5734 bool isSinglePredecessor = SI->getParent()->getSinglePredecessor();
5735
5736 if (++NumPredStores > NumberOfStoresToPredicate || !isSafePtr ||
5737 !isSinglePredecessor)
5738 return false;
5739 }
5740 if (I.mayThrow())
5741 return false;
5742 }
5743
5744 return true;
5745}
5746
5747void InterleavedAccessInfo::collectConstStrideAccesses(
5748 MapVector<Instruction *, StrideDescriptor> &AccessStrideInfo,
5749 const ValueToValueMap &Strides) {
5750 auto &DL = TheLoop->getHeader()->getModule()->getDataLayout();
5751
5752 // Since it's desired that the load/store instructions be maintained in
5753 // "program order" for the interleaved access analysis, we have to visit the
5754 // blocks in the loop in reverse postorder (i.e., in a topological order).
5755 // Such an ordering will ensure that any load/store that may be executed
5756 // before a second load/store will precede the second load/store in
5757 // AccessStrideInfo.
5758 LoopBlocksDFS DFS(TheLoop);
5759 DFS.perform(LI);
5760 for (BasicBlock *BB : make_range(DFS.beginRPO(), DFS.endRPO()))
5761 for (auto &I : *BB) {
5762 auto *LI = dyn_cast<LoadInst>(&I);
5763 auto *SI = dyn_cast<StoreInst>(&I);
5764 if (!LI && !SI)
5765 continue;
5766
5767 Value *Ptr = getPointerOperand(&I);
5768 // We don't check wrapping here because we don't know yet if Ptr will be
5769 // part of a full group or a group with gaps. Checking wrapping for all
5770 // pointers (even those that end up in groups with no gaps) will be overly
5771 // conservative. For full groups, wrapping should be ok since if we would
5772 // wrap around the address space we would do a memory access at nullptr
5773 // even without the transformation. The wrapping checks are therefore
5774 // deferred until after we've formed the interleaved groups.
5775 int64_t Stride = getPtrStride(PSE, Ptr, TheLoop, Strides,
5776 /*Assume=*/true, /*ShouldCheckWrap=*/false);
5777
5778 const SCEV *Scev = replaceSymbolicStrideSCEV(PSE, Strides, Ptr);
5779 PointerType *PtrTy = dyn_cast<PointerType>(Ptr->getType());
5780 uint64_t Size = DL.getTypeAllocSize(PtrTy->getElementType());
5781
5782 // An alignment of 0 means target ABI alignment.
5783 unsigned Align = getMemInstAlignment(&I);
5784 if (!Align)
5785 Align = DL.getABITypeAlignment(PtrTy->getElementType());
5786
5787 AccessStrideInfo[&I] = StrideDescriptor(Stride, Scev, Size, Align);
5788 }
5789}
5790
5791// Analyze interleaved accesses and collect them into interleaved load and
5792// store groups.
5793//
5794// When generating code for an interleaved load group, we effectively hoist all
5795// loads in the group to the location of the first load in program order. When
5796// generating code for an interleaved store group, we sink all stores to the
5797// location of the last store. This code motion can change the order of load
5798// and store instructions and may break dependences.
5799//
5800// The code generation strategy mentioned above ensures that we won't violate
5801// any write-after-read (WAR) dependences.
5802//
5803// E.g., for the WAR dependence: a = A[i]; // (1)
5804// A[i] = b; // (2)
5805//
5806// The store group of (2) is always inserted at or below (2), and the load
5807// group of (1) is always inserted at or above (1). Thus, the instructions will
5808// never be reordered. All other dependences are checked to ensure the
5809// correctness of the instruction reordering.
5810//
5811// The algorithm visits all memory accesses in the loop in bottom-up program
5812// order. Program order is established by traversing the blocks in the loop in
5813// reverse postorder when collecting the accesses.
5814//
5815// We visit the memory accesses in bottom-up order because it can simplify the
5816// construction of store groups in the presence of write-after-write (WAW)
5817// dependences.
5818//
5819// E.g., for the WAW dependence: A[i] = a; // (1)
5820// A[i] = b; // (2)
5821// A[i + 1] = c; // (3)
5822//
5823// We will first create a store group with (3) and (2). (1) can't be added to
5824// this group because it and (2) are dependent. However, (1) can be grouped
5825// with other accesses that may precede it in program order. Note that a
5826// bottom-up order does not imply that WAW dependences should not be checked.
5827void InterleavedAccessInfo::analyzeInterleaving(
5828 const ValueToValueMap &Strides) {
5829 DEBUG(dbgs() << "LV: Analyzing interleaved accesses...\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Analyzing interleaved accesses...\n"
; } } while (false)
;
5830
5831 // Holds all accesses with a constant stride.
5832 MapVector<Instruction *, StrideDescriptor> AccessStrideInfo;
5833 collectConstStrideAccesses(AccessStrideInfo, Strides);
5834
5835 if (AccessStrideInfo.empty())
1
Assuming the condition is false
2
Taking false branch
5836 return;
5837
5838 // Collect the dependences in the loop.
5839 collectDependences();
5840
5841 // Holds all interleaved store groups temporarily.
5842 SmallSetVector<InterleaveGroup *, 4> StoreGroups;
5843 // Holds all interleaved load groups temporarily.
5844 SmallSetVector<InterleaveGroup *, 4> LoadGroups;
5845
5846 // Search in bottom-up program order for pairs of accesses (A and B) that can
5847 // form interleaved load or store groups. In the algorithm below, access A
5848 // precedes access B in program order. We initialize a group for B in the
5849 // outer loop of the algorithm, and then in the inner loop, we attempt to
5850 // insert each A into B's group if:
5851 //
5852 // 1. A and B have the same stride,
5853 // 2. A and B have the same memory object size, and
5854 // 3. A belongs in B's group according to its distance from B.
5855 //
5856 // Special care is taken to ensure group formation will not break any
5857 // dependences.
5858 for (auto BI = AccessStrideInfo.rbegin(), E = AccessStrideInfo.rend();
3
Loop condition is true. Entering loop body
5859 BI != E; ++BI) {
5860 Instruction *B = BI->first;
5861 StrideDescriptor DesB = BI->second;
5862
5863 // Initialize a group for B if it has an allowable stride. Even if we don't
5864 // create a group for B, we continue with the bottom-up algorithm to ensure
5865 // we don't break any of B's dependences.
5866 InterleaveGroup *Group = nullptr;
4
'Group' initialized to a null pointer value
5867 if (isStrided(DesB.Stride)) {
5
Taking false branch
5868 Group = getInterleaveGroup(B);
5869 if (!Group) {
5870 DEBUG(dbgs() << "LV: Creating an interleave group with:" << *B << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Creating an interleave group with:"
<< *B << '\n'; } } while (false)
;
5871 Group = createInterleaveGroup(B, DesB.Stride, DesB.Align);
5872 }
5873 if (B->mayWriteToMemory())
5874 StoreGroups.insert(Group);
5875 else
5876 LoadGroups.insert(Group);
5877 }
5878
5879 for (auto AI = std::next(BI); AI != E; ++AI) {
6
Loop condition is true. Entering loop body
9
Loop condition is true. Entering loop body
12
Loop condition is true. Entering loop body
15
Loop condition is true. Entering loop body
5880 Instruction *A = AI->first;
5881 StrideDescriptor DesA = AI->second;
5882
5883 // Our code motion strategy implies that we can't have dependences
5884 // between accesses in an interleaved group and other accesses located
5885 // between the first and last member of the group. Note that this also
5886 // means that a group can't have more than one member at a given offset.
5887 // The accesses in a group can have dependences with other accesses, but
5888 // we must ensure we don't extend the boundaries of the group such that
5889 // we encompass those dependent accesses.
5890 //
5891 // For example, assume we have the sequence of accesses shown below in a
5892 // stride-2 loop:
5893 //
5894 // (1, 2) is a group | A[i] = a; // (1)
5895 // | A[i-1] = b; // (2) |
5896 // A[i-3] = c; // (3)
5897 // A[i] = d; // (4) | (2, 4) is not a group
5898 //
5899 // Because accesses (2) and (3) are dependent, we can group (2) with (1)
5900 // but not with (4). If we did, the dependent access (3) would be within
5901 // the boundaries of the (2, 4) group.
5902 if (!canReorderMemAccessesForInterleavedGroups(&*AI, &*BI)) {
7
Taking false branch
10
Taking false branch
13
Taking false branch
16
Taking false branch
5903 // If a dependence exists and A is already in a group, we know that A
5904 // must be a store since A precedes B and WAR dependences are allowed.
5905 // Thus, A would be sunk below B. We release A's group to prevent this
5906 // illegal code motion. A will then be free to form another group with
5907 // instructions that precede it.
5908 if (isInterleaved(A)) {
5909 InterleaveGroup *StoreGroup = getInterleaveGroup(A);
5910 StoreGroups.remove(StoreGroup);
5911 releaseGroup(StoreGroup);
5912 }
5913
5914 // If a dependence exists and A is not already in a group (or it was
5915 // and we just released it), B might be hoisted above A (if B is a
5916 // load) or another store might be sunk below A (if B is a store). In
5917 // either case, we can't add additional instructions to B's group. B
5918 // will only form a group with instructions that it precedes.
5919 break;
5920 }
5921
5922 // At this point, we've checked for illegal code motion. If either A or B
5923 // isn't strided, there's nothing left to do.
5924 if (!isStrided(DesA.Stride) || !isStrided(DesB.Stride))
17
Taking false branch
5925 continue;
8
Execution continues on line 5879
11
Execution continues on line 5879
14
Execution continues on line 5879
5926
5927 // Ignore A if it's already in a group or isn't the same kind of memory
5928 // operation as B.
5929 if (isInterleaved(A) || A->mayReadFromMemory() != B->mayReadFromMemory())
18
Assuming the condition is false
19
Taking false branch
5930 continue;
5931
5932 // Check rules 1 and 2. Ignore A if its stride or size is different from
5933 // that of B.
5934 if (DesA.Stride != DesB.Stride || DesA.Size != DesB.Size)
20
Taking false branch
5935 continue;
5936
5937 // Ignore A if the memory object of A and B don't belong to the same
5938 // address space
5939 if (getMemInstAddressSpace(A) != getMemInstAddressSpace(B))
21
Taking false branch
5940 continue;
5941
5942 // Calculate the distance from A to B.
5943 const SCEVConstant *DistToB = dyn_cast<SCEVConstant>(
5944 PSE.getSE()->getMinusSCEV(DesA.Scev, DesB.Scev));
5945 if (!DistToB)
22
Assuming 'DistToB' is non-null
23
Taking false branch
5946 continue;
5947 int64_t DistanceToB = DistToB->getAPInt().getSExtValue();
5948
5949 // Check rule 3. Ignore A if its distance to B is not a multiple of the
5950 // size.
5951 if (DistanceToB % static_cast<int64_t>(DesB.Size))
24
Taking false branch
5952 continue;
5953
5954 // Ignore A if either A or B is in a predicated block. Although we
5955 // currently prevent group formation for predicated accesses, we may be
5956 // able to relax this limitation in the future once we handle more
5957 // complicated blocks.
5958 if (isPredicated(A->getParent()) || isPredicated(B->getParent()))
25
Assuming the condition is false
26
Assuming the condition is false
27
Taking false branch
5959 continue;
5960
5961 // The index of A is the index of B plus A's distance to B in multiples
5962 // of the size.
5963 int IndexA =
5964 Group->getIndex(B) + DistanceToB / static_cast<int64_t>(DesB.Size);
28
Called C++ object pointer is null
5965
5966 // Try to insert A into B's group.
5967 if (Group->insertMember(A, IndexA, DesA.Align)) {
5968 DEBUG(dbgs() << "LV: Inserted:" << *A << '\n'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Inserted:" <<
*A << '\n' << " into the interleave group with"
<< *B << '\n'; } } while (false)
5969 << " into the interleave group with" << *B << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Inserted:" <<
*A << '\n' << " into the interleave group with"
<< *B << '\n'; } } while (false)
;
5970 InterleaveGroupMap[A] = Group;
5971
5972 // Set the first load in program order as the insert position.
5973 if (A->mayReadFromMemory())
5974 Group->setInsertPos(A);
5975 }
5976 } // Iteration over A accesses.
5977 } // Iteration over B accesses.
5978
5979 // Remove interleaved store groups with gaps.
5980 for (InterleaveGroup *Group : StoreGroups)
5981 if (Group->getNumMembers() != Group->getFactor()) {
5982 DEBUG(dbgs() << "LV: Invalidate candidate interleaved store group due "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved store group due "
"to gaps.\n"; } } while (false)
5983 "to gaps.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved store group due "
"to gaps.\n"; } } while (false)
;
5984 releaseGroup(Group);
5985 }
5986 // Remove interleaved groups with gaps (currently only loads) whose memory
5987 // accesses may wrap around. We have to revisit the getPtrStride analysis,
5988 // this time with ShouldCheckWrap=true, since collectConstStrideAccesses does
5989 // not check wrapping (see documentation there).
5990 // FORNOW we use Assume=false;
5991 // TODO: Change to Assume=true but making sure we don't exceed the threshold
5992 // of runtime SCEV assumptions checks (thereby potentially failing to
5993 // vectorize altogether).
5994 // Additional optional optimizations:
5995 // TODO: If we are peeling the loop and we know that the first pointer doesn't
5996 // wrap then we can deduce that all pointers in the group don't wrap.
5997 // This means that we can forcefully peel the loop in order to only have to
5998 // check the first pointer for no-wrap. When we'll change to use Assume=true
5999 // we'll only need at most one runtime check per interleaved group.
6000 for (InterleaveGroup *Group : LoadGroups) {
6001 // Case 1: A full group. Can Skip the checks; For full groups, if the wide
6002 // load would wrap around the address space we would do a memory access at
6003 // nullptr even without the transformation.
6004 if (Group->getNumMembers() == Group->getFactor())
6005 continue;
6006
6007 // Case 2: If first and last members of the group don't wrap this implies
6008 // that all the pointers in the group don't wrap.
6009 // So we check only group member 0 (which is always guaranteed to exist),
6010 // and group member Factor - 1; If the latter doesn't exist we rely on
6011 // peeling (if it is a non-reveresed accsess -- see Case 3).
6012 Value *FirstMemberPtr = getPointerOperand(Group->getMember(0));
6013 if (!getPtrStride(PSE, FirstMemberPtr, TheLoop, Strides, /*Assume=*/false,
6014 /*ShouldCheckWrap=*/true)) {
6015 DEBUG(dbgs() << "LV: Invalidate candidate interleaved group due to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"first group member potentially pointer-wrapping.\n"; } } while
(false)
6016 "first group member potentially pointer-wrapping.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"first group member potentially pointer-wrapping.\n"; } } while
(false)
;
6017 releaseGroup(Group);
6018 continue;
6019 }
6020 Instruction *LastMember = Group->getMember(Group->getFactor() - 1);
6021 if (LastMember) {
6022 Value *LastMemberPtr = getPointerOperand(LastMember);
6023 if (!getPtrStride(PSE, LastMemberPtr, TheLoop, Strides, /*Assume=*/false,
6024 /*ShouldCheckWrap=*/true)) {
6025 DEBUG(dbgs() << "LV: Invalidate candidate interleaved group due to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"last group member potentially pointer-wrapping.\n"; } } while
(false)
6026 "last group member potentially pointer-wrapping.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"last group member potentially pointer-wrapping.\n"; } } while
(false)
;
6027 releaseGroup(Group);
6028 }
6029 } else {
6030 // Case 3: A non-reversed interleaved load group with gaps: We need
6031 // to execute at least one scalar epilogue iteration. This will ensure
6032 // we don't speculatively access memory out-of-bounds. We only need
6033 // to look for a member at index factor - 1, since every group must have
6034 // a member at index zero.
6035 if (Group->isReverse()) {
6036 DEBUG(dbgs() << "LV: Invalidate candidate interleaved group due to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"a reverse access with gaps.\n"; } } while (false)
6037 "a reverse access with gaps.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Invalidate candidate interleaved group due to "
"a reverse access with gaps.\n"; } } while (false)
;
6038 releaseGroup(Group);
6039 continue;
6040 }
6041 DEBUG(dbgs() << "LV: Interleaved group requires epilogue iteration.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaved group requires epilogue iteration.\n"
; } } while (false)
;
6042 RequiresScalarEpilogue = true;
6043 }
6044 }
6045}
6046
6047Optional<unsigned> LoopVectorizationCostModel::computeMaxVF(bool OptForSize) {
6048 if (!EnableCondStoresVectorization && Legal->getNumPredStores()) {
6049 ORE->emit(createMissedAnalysis("ConditionalStore")
6050 << "store that is conditionally executed prevents vectorization");
6051 DEBUG(dbgs() << "LV: No vectorization. There are conditional stores.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: No vectorization. There are conditional stores.\n"
; } } while (false)
;
6052 return None;
6053 }
6054
6055 if (Legal->getRuntimePointerChecking()->Need && TTI.hasBranchDivergence()) {
6056 // TODO: It may by useful to do since it's still likely to be dynamically
6057 // uniform if the target can skip.
6058 DEBUG(dbgs() << "LV: Not inserting runtime ptr check for divergent target")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not inserting runtime ptr check for divergent target"
; } } while (false)
;
6059
6060 ORE->emit(
6061 createMissedAnalysis("CantVersionLoopWithDivergentTarget")
6062 << "runtime pointer checks needed. Not enabled for divergent target");
6063
6064 return None;
6065 }
6066
6067 unsigned TC = PSE.getSE()->getSmallConstantTripCount(TheLoop);
6068 if (!OptForSize) // Remaining checks deal with scalar loop when OptForSize.
6069 return computeFeasibleMaxVF(OptForSize, TC);
6070
6071 if (Legal->getRuntimePointerChecking()->Need) {
6072 ORE->emit(createMissedAnalysis("CantVersionLoopWithOptForSize")
6073 << "runtime pointer checks needed. Enable vectorization of this "
6074 "loop with '#pragma clang loop vectorize(enable)' when "
6075 "compiling with -Os/-Oz");
6076 DEBUG(dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. Runtime ptr check is required with -Os/-Oz.\n"
; } } while (false)
6077 << "LV: Aborting. Runtime ptr check is required with -Os/-Oz.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. Runtime ptr check is required with -Os/-Oz.\n"
; } } while (false)
;
6078 return None;
6079 }
6080
6081 // If we optimize the program for size, avoid creating the tail loop.
6082 DEBUG(dbgs() << "LV: Found trip count: " << TC << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found trip count: "
<< TC << '\n'; } } while (false)
;
6083
6084 // If we don't know the precise trip count, don't try to vectorize.
6085 if (TC < 2) {
6086 ORE->emit(
6087 createMissedAnalysis("UnknownLoopCountComplexCFG")
6088 << "unable to calculate the loop count due to complex control flow");
6089 DEBUG(dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n"
; } } while (false)
;
6090 return None;
6091 }
6092
6093 unsigned MaxVF = computeFeasibleMaxVF(OptForSize, TC);
6094
6095 if (TC % MaxVF != 0) {
6096 // If the trip count that we found modulo the vectorization factor is not
6097 // zero then we require a tail.
6098 // FIXME: look for a smaller MaxVF that does divide TC rather than give up.
6099 // FIXME: return None if loop requiresScalarEpilog(<MaxVF>), or look for a
6100 // smaller MaxVF that does not require a scalar epilog.
6101
6102 ORE->emit(createMissedAnalysis("NoTailLoopWithOptForSize")
6103 << "cannot optimize for size and vectorize at the "
6104 "same time. Enable vectorization of this loop "
6105 "with '#pragma clang loop vectorize(enable)' "
6106 "when compiling with -Os/-Oz");
6107 DEBUG(dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Aborting. A tail loop is required with -Os/-Oz.\n"
; } } while (false)
;
6108 return None;
6109 }
6110
6111 return MaxVF;
6112}
6113
6114unsigned
6115LoopVectorizationCostModel::computeFeasibleMaxVF(bool OptForSize,
6116 unsigned ConstTripCount) {
6117 MinBWs = computeMinimumValueSizes(TheLoop->getBlocks(), *DB, &TTI);
6118 unsigned SmallestType, WidestType;
6119 std::tie(SmallestType, WidestType) = getSmallestAndWidestTypes();
6120 unsigned WidestRegister = TTI.getRegisterBitWidth(true);
6121
6122 // Get the maximum safe dependence distance in bits computed by LAA.
6123 // It is computed by MaxVF * sizeOf(type) * 8, where type is taken from
6124 // the memory accesses that is most restrictive (involved in the smallest
6125 // dependence distance).
6126 unsigned MaxSafeRegisterWidth = Legal->getMaxSafeRegisterWidth();
6127
6128 WidestRegister = std::min(WidestRegister, MaxSafeRegisterWidth);
6129
6130 unsigned MaxVectorSize = WidestRegister / WidestType;
6131
6132 DEBUG(dbgs() << "LV: The Smallest and Widest types: " << SmallestType << " / "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Smallest and Widest types: "
<< SmallestType << " / " << WidestType <<
" bits.\n"; } } while (false)
6133 << WidestType << " bits.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Smallest and Widest types: "
<< SmallestType << " / " << WidestType <<
" bits.\n"; } } while (false)
;
6134 DEBUG(dbgs() << "LV: The Widest register safe to use is: " << WidestRegisterdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Widest register safe to use is: "
<< WidestRegister << " bits.\n"; } } while (false
)
6135 << " bits.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The Widest register safe to use is: "
<< WidestRegister << " bits.\n"; } } while (false
)
;
6136
6137 assert(MaxVectorSize <= 64 && "Did not expect to pack so many elements"(static_cast <bool> (MaxVectorSize <= 64 && "Did not expect to pack so many elements"
" into one vector!") ? void (0) : __assert_fail ("MaxVectorSize <= 64 && \"Did not expect to pack so many elements\" \" into one vector!\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6138, __extension__ __PRETTY_FUNCTION__))
6138 " into one vector!")(static_cast <bool> (MaxVectorSize <= 64 && "Did not expect to pack so many elements"
" into one vector!") ? void (0) : __assert_fail ("MaxVectorSize <= 64 && \"Did not expect to pack so many elements\" \" into one vector!\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6138, __extension__ __PRETTY_FUNCTION__))
;
6139 if (MaxVectorSize == 0) {
6140 DEBUG(dbgs() << "LV: The target has no vector registers.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The target has no vector registers.\n"
; } } while (false)
;
6141 MaxVectorSize = 1;
6142 return MaxVectorSize;
6143 } else if (ConstTripCount && ConstTripCount < MaxVectorSize &&
6144 isPowerOf2_32(ConstTripCount)) {
6145 // We need to clamp the VF to be the ConstTripCount. There is no point in
6146 // choosing a higher viable VF as done in the loop below.
6147 DEBUG(dbgs() << "LV: Clamping the MaxVF to the constant trip count: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Clamping the MaxVF to the constant trip count: "
<< ConstTripCount << "\n"; } } while (false)
6148 << ConstTripCount << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Clamping the MaxVF to the constant trip count: "
<< ConstTripCount << "\n"; } } while (false)
;
6149 MaxVectorSize = ConstTripCount;
6150 return MaxVectorSize;
6151 }
6152
6153 unsigned MaxVF = MaxVectorSize;
6154 if (MaximizeBandwidth && !OptForSize) {
6155 // Collect all viable vectorization factors larger than the default MaxVF
6156 // (i.e. MaxVectorSize).
6157 SmallVector<unsigned, 8> VFs;
6158 unsigned NewMaxVectorSize = WidestRegister / SmallestType;
6159 for (unsigned VS = MaxVectorSize * 2; VS <= NewMaxVectorSize; VS *= 2)
6160 VFs.push_back(VS);
6161
6162 // For each VF calculate its register usage.
6163 auto RUs = calculateRegisterUsage(VFs);
6164
6165 // Select the largest VF which doesn't require more registers than existing
6166 // ones.
6167 unsigned TargetNumRegisters = TTI.getNumberOfRegisters(true);
6168 for (int i = RUs.size() - 1; i >= 0; --i) {
6169 if (RUs[i].MaxLocalUsers <= TargetNumRegisters) {
6170 MaxVF = VFs[i];
6171 break;
6172 }
6173 }
6174 }
6175 return MaxVF;
6176}
6177
6178VectorizationFactor
6179LoopVectorizationCostModel::selectVectorizationFactor(unsigned MaxVF) {
6180 float Cost = expectedCost(1).first;
6181#ifndef NDEBUG
6182 const float ScalarCost = Cost;
6183#endif /* NDEBUG */
6184 unsigned Width = 1;
6185 DEBUG(dbgs() << "LV: Scalar loop costs: " << (int)ScalarCost << ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Scalar loop costs: "
<< (int)ScalarCost << ".\n"; } } while (false)
;
6186
6187 bool ForceVectorization = Hints->getForce() == LoopVectorizeHints::FK_Enabled;
6188 // Ignore scalar width, because the user explicitly wants vectorization.
6189 if (ForceVectorization && MaxVF > 1) {
6190 Width = 2;
6191 Cost = expectedCost(Width).first / (float)Width;
6192 }
6193
6194 for (unsigned i = 2; i <= MaxVF; i *= 2) {
6195 // Notice that the vector loop needs to be executed less times, so
6196 // we need to divide the cost of the vector loops by the width of
6197 // the vector elements.
6198 VectorizationCostTy C = expectedCost(i);
6199 float VectorCost = C.first / (float)i;
6200 DEBUG(dbgs() << "LV: Vector loop of width " << ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Vector loop of width "
<< i << " costs: " << (int)VectorCost <<
".\n"; } } while (false)
6201 << " costs: " << (int)VectorCost << ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Vector loop of width "
<< i << " costs: " << (int)VectorCost <<
".\n"; } } while (false)
;
6202 if (!C.second && !ForceVectorization) {
6203 DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not considering vector loop of width "
<< i << " because it will not generate any vector instructions.\n"
; } } while (false)
6204 dbgs() << "LV: Not considering vector loop of width " << ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not considering vector loop of width "
<< i << " because it will not generate any vector instructions.\n"
; } } while (false)
6205 << " because it will not generate any vector instructions.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not considering vector loop of width "
<< i << " because it will not generate any vector instructions.\n"
; } } while (false)
;
6206 continue;
6207 }
6208 if (VectorCost < Cost) {
6209 Cost = VectorCost;
6210 Width = i;
6211 }
6212 }
6213
6214 DEBUG(if (ForceVectorization && Width > 1 && Cost >= ScalarCost) dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (ForceVectorization && Width
> 1 && Cost >= ScalarCost) dbgs() << "LV: Vectorization seems to be not beneficial, "
<< "but was forced by a user.\n"; } } while (false)
6215 << "LV: Vectorization seems to be not beneficial, "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (ForceVectorization && Width
> 1 && Cost >= ScalarCost) dbgs() << "LV: Vectorization seems to be not beneficial, "
<< "but was forced by a user.\n"; } } while (false)
6216 << "but was forced by a user.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { if (ForceVectorization && Width
> 1 && Cost >= ScalarCost) dbgs() << "LV: Vectorization seems to be not beneficial, "
<< "but was forced by a user.\n"; } } while (false)
;
6217 DEBUG(dbgs() << "LV: Selecting VF: " << Width << ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Selecting VF: " <<
Width << ".\n"; } } while (false)
;
6218 VectorizationFactor Factor = {Width, (unsigned)(Width * Cost)};
6219 return Factor;
6220}
6221
6222std::pair<unsigned, unsigned>
6223LoopVectorizationCostModel::getSmallestAndWidestTypes() {
6224 unsigned MinWidth = -1U;
6225 unsigned MaxWidth = 8;
6226 const DataLayout &DL = TheFunction->getParent()->getDataLayout();
6227
6228 // For each block.
6229 for (BasicBlock *BB : TheLoop->blocks()) {
6230 // For each instruction in the loop.
6231 for (Instruction &I : *BB) {
6232 Type *T = I.getType();
6233
6234 // Skip ignored values.
6235 if (ValuesToIgnore.count(&I))
6236 continue;
6237
6238 // Only examine Loads, Stores and PHINodes.
6239 if (!isa<LoadInst>(I) && !isa<StoreInst>(I) && !isa<PHINode>(I))
6240 continue;
6241
6242 // Examine PHI nodes that are reduction variables. Update the type to
6243 // account for the recurrence type.
6244 if (auto *PN = dyn_cast<PHINode>(&I)) {
6245 if (!Legal->isReductionVariable(PN))
6246 continue;
6247 RecurrenceDescriptor RdxDesc = (*Legal->getReductionVars())[PN];
6248 T = RdxDesc.getRecurrenceType();
6249 }
6250
6251 // Examine the stored values.
6252 if (auto *ST = dyn_cast<StoreInst>(&I))
6253 T = ST->getValueOperand()->getType();
6254
6255 // Ignore loaded pointer types and stored pointer types that are not
6256 // vectorizable.
6257 //
6258 // FIXME: The check here attempts to predict whether a load or store will
6259 // be vectorized. We only know this for certain after a VF has
6260 // been selected. Here, we assume that if an access can be
6261 // vectorized, it will be. We should also look at extending this
6262 // optimization to non-pointer types.
6263 //
6264 if (T->isPointerTy() && !isConsecutiveLoadOrStore(&I) &&
6265 !Legal->isAccessInterleaved(&I) && !Legal->isLegalGatherOrScatter(&I))
6266 continue;
6267
6268 MinWidth = std::min(MinWidth,
6269 (unsigned)DL.getTypeSizeInBits(T->getScalarType()));
6270 MaxWidth = std::max(MaxWidth,
6271 (unsigned)DL.getTypeSizeInBits(T->getScalarType()));
6272 }
6273 }
6274
6275 return {MinWidth, MaxWidth};
6276}
6277
6278unsigned LoopVectorizationCostModel::selectInterleaveCount(bool OptForSize,
6279 unsigned VF,
6280 unsigned LoopCost) {
6281 // -- The interleave heuristics --
6282 // We interleave the loop in order to expose ILP and reduce the loop overhead.
6283 // There are many micro-architectural considerations that we can't predict
6284 // at this level. For example, frontend pressure (on decode or fetch) due to
6285 // code size, or the number and capabilities of the execution ports.
6286 //
6287 // We use the following heuristics to select the interleave count:
6288 // 1. If the code has reductions, then we interleave to break the cross
6289 // iteration dependency.
6290 // 2. If the loop is really small, then we interleave to reduce the loop
6291 // overhead.
6292 // 3. We don't interleave if we think that we will spill registers to memory
6293 // due to the increased register pressure.
6294
6295 // When we optimize for size, we don't interleave.
6296 if (OptForSize)
6297 return 1;
6298
6299 // We used the distance for the interleave count.
6300 if (Legal->getMaxSafeDepDistBytes() != -1U)
6301 return 1;
6302
6303 // Do not interleave loops with a relatively small trip count.
6304 unsigned TC = PSE.getSE()->getSmallConstantTripCount(TheLoop);
6305 if (TC > 1 && TC < TinyTripCountInterleaveThreshold)
6306 return 1;
6307
6308 unsigned TargetNumRegisters = TTI.getNumberOfRegisters(VF > 1);
6309 DEBUG(dbgs() << "LV: The target has " << TargetNumRegistersdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The target has " <<
TargetNumRegisters << " registers\n"; } } while (false
)
6310 << " registers\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: The target has " <<
TargetNumRegisters << " registers\n"; } } while (false
)
;
6311
6312 if (VF == 1) {
6313 if (ForceTargetNumScalarRegs.getNumOccurrences() > 0)
6314 TargetNumRegisters = ForceTargetNumScalarRegs;
6315 } else {
6316 if (ForceTargetNumVectorRegs.getNumOccurrences() > 0)
6317 TargetNumRegisters = ForceTargetNumVectorRegs;
6318 }
6319
6320 RegisterUsage R = calculateRegisterUsage({VF})[0];
6321 // We divide by these constants so assume that we have at least one
6322 // instruction that uses at least one register.
6323 R.MaxLocalUsers = std::max(R.MaxLocalUsers, 1U);
6324 R.NumInstructions = std::max(R.NumInstructions, 1U);
6325
6326 // We calculate the interleave count using the following formula.
6327 // Subtract the number of loop invariants from the number of available
6328 // registers. These registers are used by all of the interleaved instances.
6329 // Next, divide the remaining registers by the number of registers that is
6330 // required by the loop, in order to estimate how many parallel instances
6331 // fit without causing spills. All of this is rounded down if necessary to be
6332 // a power of two. We want power of two interleave count to simplify any
6333 // addressing operations or alignment considerations.
6334 unsigned IC = PowerOf2Floor((TargetNumRegisters - R.LoopInvariantRegs) /
6335 R.MaxLocalUsers);
6336
6337 // Don't count the induction variable as interleaved.
6338 if (EnableIndVarRegisterHeur)
6339 IC = PowerOf2Floor((TargetNumRegisters - R.LoopInvariantRegs - 1) /
6340 std::max(1U, (R.MaxLocalUsers - 1)));
6341
6342 // Clamp the interleave ranges to reasonable counts.
6343 unsigned MaxInterleaveCount = TTI.getMaxInterleaveFactor(VF);
6344
6345 // Check if the user has overridden the max.
6346 if (VF == 1) {
6347 if (ForceTargetMaxScalarInterleaveFactor.getNumOccurrences() > 0)
6348 MaxInterleaveCount = ForceTargetMaxScalarInterleaveFactor;
6349 } else {
6350 if (ForceTargetMaxVectorInterleaveFactor.getNumOccurrences() > 0)
6351 MaxInterleaveCount = ForceTargetMaxVectorInterleaveFactor;
6352 }
6353
6354 // If we did not calculate the cost for VF (because the user selected the VF)
6355 // then we calculate the cost of VF here.
6356 if (LoopCost == 0)
6357 LoopCost = expectedCost(VF).first;
6358
6359 // Clamp the calculated IC to be between the 1 and the max interleave count
6360 // that the target allows.
6361 if (IC > MaxInterleaveCount)
6362 IC = MaxInterleaveCount;
6363 else if (IC < 1)
6364 IC = 1;
6365
6366 // Interleave if we vectorized this loop and there is a reduction that could
6367 // benefit from interleaving.
6368 if (VF > 1 && !Legal->getReductionVars()->empty()) {
6369 DEBUG(dbgs() << "LV: Interleaving because of reductions.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving because of reductions.\n"
; } } while (false)
;
6370 return IC;
6371 }
6372
6373 // Note that if we've already vectorized the loop we will have done the
6374 // runtime check and so interleaving won't require further checks.
6375 bool InterleavingRequiresRuntimePointerCheck =
6376 (VF == 1 && Legal->getRuntimePointerChecking()->Need);
6377
6378 // We want to interleave small loops in order to reduce the loop overhead and
6379 // potentially expose ILP opportunities.
6380 DEBUG(dbgs() << "LV: Loop cost is " << LoopCost << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop cost is " <<
LoopCost << '\n'; } } while (false)
;
6381 if (!InterleavingRequiresRuntimePointerCheck && LoopCost < SmallLoopCost) {
6382 // We assume that the cost overhead is 1 and we use the cost model
6383 // to estimate the cost of the loop and interleave until the cost of the
6384 // loop overhead is about 5% of the cost of the loop.
6385 unsigned SmallIC =
6386 std::min(IC, (unsigned)PowerOf2Floor(SmallLoopCost / LoopCost));
6387
6388 // Interleave until store/load ports (estimated by max interleave count) are
6389 // saturated.
6390 unsigned NumStores = Legal->getNumStores();
6391 unsigned NumLoads = Legal->getNumLoads();
6392 unsigned StoresIC = IC / (NumStores ? NumStores : 1);
6393 unsigned LoadsIC = IC / (NumLoads ? NumLoads : 1);
6394
6395 // If we have a scalar reduction (vector reductions are already dealt with
6396 // by this point), we can increase the critical path length if the loop
6397 // we're interleaving is inside another loop. Limit, by default to 2, so the
6398 // critical path only gets increased by one reduction operation.
6399 if (!Legal->getReductionVars()->empty() && TheLoop->getLoopDepth() > 1) {
6400 unsigned F = static_cast<unsigned>(MaxNestedScalarReductionIC);
6401 SmallIC = std::min(SmallIC, F);
6402 StoresIC = std::min(StoresIC, F);
6403 LoadsIC = std::min(LoadsIC, F);
6404 }
6405
6406 if (EnableLoadStoreRuntimeInterleave &&
6407 std::max(StoresIC, LoadsIC) > SmallIC) {
6408 DEBUG(dbgs() << "LV: Interleaving to saturate store or load ports.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving to saturate store or load ports.\n"
; } } while (false)
;
6409 return std::max(StoresIC, LoadsIC);
6410 }
6411
6412 DEBUG(dbgs() << "LV: Interleaving to reduce branch cost.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving to reduce branch cost.\n"
; } } while (false)
;
6413 return SmallIC;
6414 }
6415
6416 // Interleave if this is a large loop (small loops are already dealt with by
6417 // this point) that could benefit from interleaving.
6418 bool HasReductions = !Legal->getReductionVars()->empty();
6419 if (TTI.enableAggressiveInterleaving(HasReductions)) {
6420 DEBUG(dbgs() << "LV: Interleaving to expose ILP.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving to expose ILP.\n"
; } } while (false)
;
6421 return IC;
6422 }
6423
6424 DEBUG(dbgs() << "LV: Not Interleaving.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not Interleaving.\n"
; } } while (false)
;
6425 return 1;
6426}
6427
6428SmallVector<LoopVectorizationCostModel::RegisterUsage, 8>
6429LoopVectorizationCostModel::calculateRegisterUsage(ArrayRef<unsigned> VFs) {
6430 // This function calculates the register usage by measuring the highest number
6431 // of values that are alive at a single location. Obviously, this is a very
6432 // rough estimation. We scan the loop in a topological order in order and
6433 // assign a number to each instruction. We use RPO to ensure that defs are
6434 // met before their users. We assume that each instruction that has in-loop
6435 // users starts an interval. We record every time that an in-loop value is
6436 // used, so we have a list of the first and last occurrences of each
6437 // instruction. Next, we transpose this data structure into a multi map that
6438 // holds the list of intervals that *end* at a specific location. This multi
6439 // map allows us to perform a linear search. We scan the instructions linearly
6440 // and record each time that a new interval starts, by placing it in a set.
6441 // If we find this value in the multi-map then we remove it from the set.
6442 // The max register usage is the maximum size of the set.
6443 // We also search for instructions that are defined outside the loop, but are
6444 // used inside the loop. We need this number separately from the max-interval
6445 // usage number because when we unroll, loop-invariant values do not take
6446 // more register.
6447 LoopBlocksDFS DFS(TheLoop);
6448 DFS.perform(LI);
6449
6450 RegisterUsage RU;
6451 RU.NumInstructions = 0;
6452
6453 // Each 'key' in the map opens a new interval. The values
6454 // of the map are the index of the 'last seen' usage of the
6455 // instruction that is the key.
6456 using IntervalMap = DenseMap<Instruction *, unsigned>;
6457
6458 // Maps instruction to its index.
6459 DenseMap<unsigned, Instruction *> IdxToInstr;
6460 // Marks the end of each interval.
6461 IntervalMap EndPoint;
6462 // Saves the list of instruction indices that are used in the loop.
6463 SmallSet<Instruction *, 8> Ends;
6464 // Saves the list of values that are used in the loop but are
6465 // defined outside the loop, such as arguments and constants.
6466 SmallPtrSet<Value *, 8> LoopInvariants;
6467
6468 unsigned Index = 0;
6469 for (BasicBlock *BB : make_range(DFS.beginRPO(), DFS.endRPO())) {
6470 RU.NumInstructions += BB->size();
6471 for (Instruction &I : *BB) {
6472 IdxToInstr[Index++] = &I;
6473
6474 // Save the end location of each USE.
6475 for (Value *U : I.operands()) {
6476 auto *Instr = dyn_cast<Instruction>(U);
6477
6478 // Ignore non-instruction values such as arguments, constants, etc.
6479 if (!Instr)
6480 continue;
6481
6482 // If this instruction is outside the loop then record it and continue.
6483 if (!TheLoop->contains(Instr)) {
6484 LoopInvariants.insert(Instr);
6485 continue;
6486 }
6487
6488 // Overwrite previous end points.
6489 EndPoint[Instr] = Index;
6490 Ends.insert(Instr);
6491 }
6492 }
6493 }
6494
6495 // Saves the list of intervals that end with the index in 'key'.
6496 using InstrList = SmallVector<Instruction *, 2>;
6497 DenseMap<unsigned, InstrList> TransposeEnds;
6498
6499 // Transpose the EndPoints to a list of values that end at each index.
6500 for (auto &Interval : EndPoint)
6501 TransposeEnds[Interval.second].push_back(Interval.first);
6502
6503 SmallSet<Instruction *, 8> OpenIntervals;
6504
6505 // Get the size of the widest register.
6506 unsigned MaxSafeDepDist = -1U;
6507 if (Legal->getMaxSafeDepDistBytes() != -1U)
6508 MaxSafeDepDist = Legal->getMaxSafeDepDistBytes() * 8;
6509 unsigned WidestRegister =
6510 std::min(TTI.getRegisterBitWidth(true), MaxSafeDepDist);
6511 const DataLayout &DL = TheFunction->getParent()->getDataLayout();
6512
6513 SmallVector<RegisterUsage, 8> RUs(VFs.size());
6514 SmallVector<unsigned, 8> MaxUsages(VFs.size(), 0);
6515
6516 DEBUG(dbgs() << "LV(REG): Calculating max register usage:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): Calculating max register usage:\n"
; } } while (false)
;
6517
6518 // A lambda that gets the register usage for the given type and VF.
6519 auto GetRegUsage = [&DL, WidestRegister](Type *Ty, unsigned VF) {
6520 if (Ty->isTokenTy())
6521 return 0U;
6522 unsigned TypeSize = DL.getTypeSizeInBits(Ty->getScalarType());
6523 return std::max<unsigned>(1, VF * TypeSize / WidestRegister);
6524 };
6525
6526 for (unsigned int i = 0; i < Index; ++i) {
6527 Instruction *I = IdxToInstr[i];
6528
6529 // Remove all of the instructions that end at this location.
6530 InstrList &List = TransposeEnds[i];
6531 for (Instruction *ToRemove : List)
6532 OpenIntervals.erase(ToRemove);
6533
6534 // Ignore instructions that are never used within the loop.
6535 if (!Ends.count(I))
6536 continue;
6537
6538 // Skip ignored values.
6539 if (ValuesToIgnore.count(I))
6540 continue;
6541
6542 // For each VF find the maximum usage of registers.
6543 for (unsigned j = 0, e = VFs.size(); j < e; ++j) {
6544 if (VFs[j] == 1) {
6545 MaxUsages[j] = std::max(MaxUsages[j], OpenIntervals.size());
6546 continue;
6547 }
6548 collectUniformsAndScalars(VFs[j]);
6549 // Count the number of live intervals.
6550 unsigned RegUsage = 0;
6551 for (auto Inst : OpenIntervals) {
6552 // Skip ignored values for VF > 1.
6553 if (VecValuesToIgnore.count(Inst) ||
6554 isScalarAfterVectorization(Inst, VFs[j]))
6555 continue;
6556 RegUsage += GetRegUsage(Inst->getType(), VFs[j]);
6557 }
6558 MaxUsages[j] = std::max(MaxUsages[j], RegUsage);
6559 }
6560
6561 DEBUG(dbgs() << "LV(REG): At #" << i << " Interval # "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): At #" <<
i << " Interval # " << OpenIntervals.size() <<
'\n'; } } while (false)
6562 << OpenIntervals.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): At #" <<
i << " Interval # " << OpenIntervals.size() <<
'\n'; } } while (false)
;
6563
6564 // Add the current instruction to the list of open intervals.
6565 OpenIntervals.insert(I);
6566 }
6567
6568 for (unsigned i = 0, e = VFs.size(); i < e; ++i) {
6569 unsigned Invariant = 0;
6570 if (VFs[i] == 1)
6571 Invariant = LoopInvariants.size();
6572 else {
6573 for (auto Inst : LoopInvariants)
6574 Invariant += GetRegUsage(Inst->getType(), VFs[i]);
6575 }
6576
6577 DEBUG(dbgs() << "LV(REG): VF = " << VFs[i] << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): VF = " <<
VFs[i] << '\n'; } } while (false)
;
6578 DEBUG(dbgs() << "LV(REG): Found max usage: " << MaxUsages[i] << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): Found max usage: "
<< MaxUsages[i] << '\n'; } } while (false)
;
6579 DEBUG(dbgs() << "LV(REG): Found invariant usage: " << Invariant << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): Found invariant usage: "
<< Invariant << '\n'; } } while (false)
;
6580 DEBUG(dbgs() << "LV(REG): LoopSize: " << RU.NumInstructions << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV(REG): LoopSize: " <<
RU.NumInstructions << '\n'; } } while (false)
;
6581
6582 RU.LoopInvariantRegs = Invariant;
6583 RU.MaxLocalUsers = MaxUsages[i];
6584 RUs[i] = RU;
6585 }
6586
6587 return RUs;
6588}
6589
6590void LoopVectorizationCostModel::collectInstsToScalarize(unsigned VF) {
6591 // If we aren't vectorizing the loop, or if we've already collected the
6592 // instructions to scalarize, there's nothing to do. Collection may already
6593 // have occurred if we have a user-selected VF and are now computing the
6594 // expected cost for interleaving.
6595 if (VF < 2 || InstsToScalarize.count(VF))
6596 return;
6597
6598 // Initialize a mapping for VF in InstsToScalalarize. If we find that it's
6599 // not profitable to scalarize any instructions, the presence of VF in the
6600 // map will indicate that we've analyzed it already.
6601 ScalarCostsTy &ScalarCostsVF = InstsToScalarize[VF];
6602
6603 // Find all the instructions that are scalar with predication in the loop and
6604 // determine if it would be better to not if-convert the blocks they are in.
6605 // If so, we also record the instructions to scalarize.
6606 for (BasicBlock *BB : TheLoop->blocks()) {
6607 if (!Legal->blockNeedsPredication(BB))
6608 continue;
6609 for (Instruction &I : *BB)
6610 if (Legal->isScalarWithPredication(&I)) {
6611 ScalarCostsTy ScalarCosts;
6612 if (computePredInstDiscount(&I, ScalarCosts, VF) >= 0)
6613 ScalarCostsVF.insert(ScalarCosts.begin(), ScalarCosts.end());
6614
6615 // Remember that BB will remain after vectorization.
6616 PredicatedBBsAfterVectorization.insert(BB);
6617 }
6618 }
6619}
6620
6621int LoopVectorizationCostModel::computePredInstDiscount(
6622 Instruction *PredInst, DenseMap<Instruction *, unsigned> &ScalarCosts,
6623 unsigned VF) {
6624 assert(!isUniformAfterVectorization(PredInst, VF) &&(static_cast <bool> (!isUniformAfterVectorization(PredInst
, VF) && "Instruction marked uniform-after-vectorization will be predicated"
) ? void (0) : __assert_fail ("!isUniformAfterVectorization(PredInst, VF) && \"Instruction marked uniform-after-vectorization will be predicated\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6625, __extension__ __PRETTY_FUNCTION__))
6625 "Instruction marked uniform-after-vectorization will be predicated")(static_cast <bool> (!isUniformAfterVectorization(PredInst
, VF) && "Instruction marked uniform-after-vectorization will be predicated"
) ? void (0) : __assert_fail ("!isUniformAfterVectorization(PredInst, VF) && \"Instruction marked uniform-after-vectorization will be predicated\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6625, __extension__ __PRETTY_FUNCTION__))
;
6626
6627 // Initialize the discount to zero, meaning that the scalar version and the
6628 // vector version cost the same.
6629 int Discount = 0;
6630
6631 // Holds instructions to analyze. The instructions we visit are mapped in
6632 // ScalarCosts. Those instructions are the ones that would be scalarized if
6633 // we find that the scalar version costs less.
6634 SmallVector<Instruction *, 8> Worklist;
6635
6636 // Returns true if the given instruction can be scalarized.
6637 auto canBeScalarized = [&](Instruction *I) -> bool {
6638 // We only attempt to scalarize instructions forming a single-use chain
6639 // from the original predicated block that would otherwise be vectorized.
6640 // Although not strictly necessary, we give up on instructions we know will
6641 // already be scalar to avoid traversing chains that are unlikely to be
6642 // beneficial.
6643 if (!I->hasOneUse() || PredInst->getParent() != I->getParent() ||
6644 isScalarAfterVectorization(I, VF))
6645 return false;
6646
6647 // If the instruction is scalar with predication, it will be analyzed
6648 // separately. We ignore it within the context of PredInst.
6649 if (Legal->isScalarWithPredication(I))
6650 return false;
6651
6652 // If any of the instruction's operands are uniform after vectorization,
6653 // the instruction cannot be scalarized. This prevents, for example, a
6654 // masked load from being scalarized.
6655 //
6656 // We assume we will only emit a value for lane zero of an instruction
6657 // marked uniform after vectorization, rather than VF identical values.
6658 // Thus, if we scalarize an instruction that uses a uniform, we would
6659 // create uses of values corresponding to the lanes we aren't emitting code
6660 // for. This behavior can be changed by allowing getScalarValue to clone
6661 // the lane zero values for uniforms rather than asserting.
6662 for (Use &U : I->operands())
6663 if (auto *J = dyn_cast<Instruction>(U.get()))
6664 if (isUniformAfterVectorization(J, VF))
6665 return false;
6666
6667 // Otherwise, we can scalarize the instruction.
6668 return true;
6669 };
6670
6671 // Returns true if an operand that cannot be scalarized must be extracted
6672 // from a vector. We will account for this scalarization overhead below. Note
6673 // that the non-void predicated instructions are placed in their own blocks,
6674 // and their return values are inserted into vectors. Thus, an extract would
6675 // still be required.
6676 auto needsExtract = [&](Instruction *I) -> bool {
6677 return TheLoop->contains(I) && !isScalarAfterVectorization(I, VF);
6678 };
6679
6680 // Compute the expected cost discount from scalarizing the entire expression
6681 // feeding the predicated instruction. We currently only consider expressions
6682 // that are single-use instruction chains.
6683 Worklist.push_back(PredInst);
6684 while (!Worklist.empty()) {
6685 Instruction *I = Worklist.pop_back_val();
6686
6687 // If we've already analyzed the instruction, there's nothing to do.
6688 if (ScalarCosts.count(I))
6689 continue;
6690
6691 // Compute the cost of the vector instruction. Note that this cost already
6692 // includes the scalarization overhead of the predicated instruction.
6693 unsigned VectorCost = getInstructionCost(I, VF).first;
6694
6695 // Compute the cost of the scalarized instruction. This cost is the cost of
6696 // the instruction as if it wasn't if-converted and instead remained in the
6697 // predicated block. We will scale this cost by block probability after
6698 // computing the scalarization overhead.
6699 unsigned ScalarCost = VF * getInstructionCost(I, 1).first;
6700
6701 // Compute the scalarization overhead of needed insertelement instructions
6702 // and phi nodes.
6703 if (Legal->isScalarWithPredication(I) && !I->getType()->isVoidTy()) {
6704 ScalarCost += TTI.getScalarizationOverhead(ToVectorTy(I->getType(), VF),
6705 true, false);
6706 ScalarCost += VF * TTI.getCFInstrCost(Instruction::PHI);
6707 }
6708
6709 // Compute the scalarization overhead of needed extractelement
6710 // instructions. For each of the instruction's operands, if the operand can
6711 // be scalarized, add it to the worklist; otherwise, account for the
6712 // overhead.
6713 for (Use &U : I->operands())
6714 if (auto *J = dyn_cast<Instruction>(U.get())) {
6715 assert(VectorType::isValidElementType(J->getType()) &&(static_cast <bool> (VectorType::isValidElementType(J->
getType()) && "Instruction has non-scalar type") ? void
(0) : __assert_fail ("VectorType::isValidElementType(J->getType()) && \"Instruction has non-scalar type\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6716, __extension__ __PRETTY_FUNCTION__))
6716 "Instruction has non-scalar type")(static_cast <bool> (VectorType::isValidElementType(J->
getType()) && "Instruction has non-scalar type") ? void
(0) : __assert_fail ("VectorType::isValidElementType(J->getType()) && \"Instruction has non-scalar type\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6716, __extension__ __PRETTY_FUNCTION__))
;
6717 if (canBeScalarized(J))
6718 Worklist.push_back(J);
6719 else if (needsExtract(J))
6720 ScalarCost += TTI.getScalarizationOverhead(
6721 ToVectorTy(J->getType(),VF), false, true);
6722 }
6723
6724 // Scale the total scalar cost by block probability.
6725 ScalarCost /= getReciprocalPredBlockProb();
6726
6727 // Compute the discount. A non-negative discount means the vector version
6728 // of the instruction costs more, and scalarizing would be beneficial.
6729 Discount += VectorCost - ScalarCost;
6730 ScalarCosts[I] = ScalarCost;
6731 }
6732
6733 return Discount;
6734}
6735
6736LoopVectorizationCostModel::VectorizationCostTy
6737LoopVectorizationCostModel::expectedCost(unsigned VF) {
6738 VectorizationCostTy Cost;
6739
6740 // For each block.
6741 for (BasicBlock *BB : TheLoop->blocks()) {
6742 VectorizationCostTy BlockCost;
6743
6744 // For each instruction in the old loop.
6745 for (Instruction &I : *BB) {
6746 // Skip dbg intrinsics.
6747 if (isa<DbgInfoIntrinsic>(I))
6748 continue;
6749
6750 // Skip ignored values.
6751 if (ValuesToIgnore.count(&I) ||
6752 (VF > 1 && VecValuesToIgnore.count(&I)))
6753 continue;
6754
6755 VectorizationCostTy C = getInstructionCost(&I, VF);
6756
6757 // Check if we should override the cost.
6758 if (ForceTargetInstructionCost.getNumOccurrences() > 0)
6759 C.first = ForceTargetInstructionCost;
6760
6761 BlockCost.first += C.first;
6762 BlockCost.second |= C.second;
6763 DEBUG(dbgs() << "LV: Found an estimated cost of " << C.first << " for VF "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an estimated cost of "
<< C.first << " for VF " << VF << " For instruction: "
<< I << '\n'; } } while (false)
6764 << VF << " For instruction: " << I << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found an estimated cost of "
<< C.first << " for VF " << VF << " For instruction: "
<< I << '\n'; } } while (false)
;
6765 }
6766
6767 // If we are vectorizing a predicated block, it will have been
6768 // if-converted. This means that the block's instructions (aside from
6769 // stores and instructions that may divide by zero) will now be
6770 // unconditionally executed. For the scalar case, we may not always execute
6771 // the predicated block. Thus, scale the block's cost by the probability of
6772 // executing it.
6773 if (VF == 1 && Legal->blockNeedsPredication(BB))
6774 BlockCost.first /= getReciprocalPredBlockProb();
6775
6776 Cost.first += BlockCost.first;
6777 Cost.second |= BlockCost.second;
6778 }
6779
6780 return Cost;
6781}
6782
6783/// \brief Gets Address Access SCEV after verifying that the access pattern
6784/// is loop invariant except the induction variable dependence.
6785///
6786/// This SCEV can be sent to the Target in order to estimate the address
6787/// calculation cost.
6788static const SCEV *getAddressAccessSCEV(
6789 Value *Ptr,
6790 LoopVectorizationLegality *Legal,
6791 PredicatedScalarEvolution &PSE,
6792 const Loop *TheLoop) {
6793
6794 auto *Gep = dyn_cast<GetElementPtrInst>(Ptr);
6795 if (!Gep)
6796 return nullptr;
6797
6798 // We are looking for a gep with all loop invariant indices except for one
6799 // which should be an induction variable.
6800 auto SE = PSE.getSE();
6801 unsigned NumOperands = Gep->getNumOperands();
6802 for (unsigned i = 1; i < NumOperands; ++i) {
6803 Value *Opd = Gep->getOperand(i);
6804 if (!SE->isLoopInvariant(SE->getSCEV(Opd), TheLoop) &&
6805 !Legal->isInductionVariable(Opd))
6806 return nullptr;
6807 }
6808
6809 // Now we know we have a GEP ptr, %inv, %ind, %inv. return the Ptr SCEV.
6810 return PSE.getSCEV(Ptr);
6811}
6812
6813static bool isStrideMul(Instruction *I, LoopVectorizationLegality *Legal) {
6814 return Legal->hasStride(I->getOperand(0)) ||
6815 Legal->hasStride(I->getOperand(1));
6816}
6817
6818unsigned LoopVectorizationCostModel::getMemInstScalarizationCost(Instruction *I,
6819 unsigned VF) {
6820 Type *ValTy = getMemInstValueType(I);
6821 auto SE = PSE.getSE();
6822
6823 unsigned Alignment = getMemInstAlignment(I);
6824 unsigned AS = getMemInstAddressSpace(I);
6825 Value *Ptr = getPointerOperand(I);
6826 Type *PtrTy = ToVectorTy(Ptr->getType(), VF);
6827
6828 // Figure out whether the access is strided and get the stride value
6829 // if it's known in compile time
6830 const SCEV *PtrSCEV = getAddressAccessSCEV(Ptr, Legal, PSE, TheLoop);
6831
6832 // Get the cost of the scalar memory instruction and address computation.
6833 unsigned Cost = VF * TTI.getAddressComputationCost(PtrTy, SE, PtrSCEV);
6834
6835 Cost += VF *
6836 TTI.getMemoryOpCost(I->getOpcode(), ValTy->getScalarType(), Alignment,
6837 AS, I);
6838
6839 // Get the overhead of the extractelement and insertelement instructions
6840 // we might create due to scalarization.
6841 Cost += getScalarizationOverhead(I, VF, TTI);
6842
6843 // If we have a predicated store, it may not be executed for each vector
6844 // lane. Scale the cost by the probability of executing the predicated
6845 // block.
6846 if (Legal->isScalarWithPredication(I))
6847 Cost /= getReciprocalPredBlockProb();
6848
6849 return Cost;
6850}
6851
6852unsigned LoopVectorizationCostModel::getConsecutiveMemOpCost(Instruction *I,
6853 unsigned VF) {
6854 Type *ValTy = getMemInstValueType(I);
6855 Type *VectorTy = ToVectorTy(ValTy, VF);
6856 unsigned Alignment = getMemInstAlignment(I);
6857 Value *Ptr = getPointerOperand(I);
6858 unsigned AS = getMemInstAddressSpace(I);
6859 int ConsecutiveStride = Legal->isConsecutivePtr(Ptr);
6860
6861 assert((ConsecutiveStride == 1 || ConsecutiveStride == -1) &&(static_cast <bool> ((ConsecutiveStride == 1 || ConsecutiveStride
== -1) && "Stride should be 1 or -1 for consecutive memory access"
) ? void (0) : __assert_fail ("(ConsecutiveStride == 1 || ConsecutiveStride == -1) && \"Stride should be 1 or -1 for consecutive memory access\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6862, __extension__ __PRETTY_FUNCTION__))
6862 "Stride should be 1 or -1 for consecutive memory access")(static_cast <bool> ((ConsecutiveStride == 1 || ConsecutiveStride
== -1) && "Stride should be 1 or -1 for consecutive memory access"
) ? void (0) : __assert_fail ("(ConsecutiveStride == 1 || ConsecutiveStride == -1) && \"Stride should be 1 or -1 for consecutive memory access\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6862, __extension__ __PRETTY_FUNCTION__))
;
6863 unsigned Cost = 0;
6864 if (Legal->isMaskRequired(I))
6865 Cost += TTI.getMaskedMemoryOpCost(I->getOpcode(), VectorTy, Alignment, AS);
6866 else
6867 Cost += TTI.getMemoryOpCost(I->getOpcode(), VectorTy, Alignment, AS, I);
6868
6869 bool Reverse = ConsecutiveStride < 0;
6870 if (Reverse)
6871 Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse, VectorTy, 0);
6872 return Cost;
6873}
6874
6875unsigned LoopVectorizationCostModel::getUniformMemOpCost(Instruction *I,
6876 unsigned VF) {
6877 LoadInst *LI = cast<LoadInst>(I);
6878 Type *ValTy = LI->getType();
6879 Type *VectorTy = ToVectorTy(ValTy, VF);
6880 unsigned Alignment = LI->getAlignment();
6881 unsigned AS = LI->getPointerAddressSpace();
6882
6883 return TTI.getAddressComputationCost(ValTy) +
6884 TTI.getMemoryOpCost(Instruction::Load, ValTy, Alignment, AS) +
6885 TTI.getShuffleCost(TargetTransformInfo::SK_Broadcast, VectorTy);
6886}
6887
6888unsigned LoopVectorizationCostModel::getGatherScatterCost(Instruction *I,
6889 unsigned VF) {
6890 Type *ValTy = getMemInstValueType(I);
6891 Type *VectorTy = ToVectorTy(ValTy, VF);
6892 unsigned Alignment = getMemInstAlignment(I);
6893 Value *Ptr = getPointerOperand(I);
6894
6895 return TTI.getAddressComputationCost(VectorTy) +
6896 TTI.getGatherScatterOpCost(I->getOpcode(), VectorTy, Ptr,
6897 Legal->isMaskRequired(I), Alignment);
6898}
6899
6900unsigned LoopVectorizationCostModel::getInterleaveGroupCost(Instruction *I,
6901 unsigned VF) {
6902 Type *ValTy = getMemInstValueType(I);
6903 Type *VectorTy = ToVectorTy(ValTy, VF);
6904 unsigned AS = getMemInstAddressSpace(I);
6905
6906 auto Group = Legal->getInterleavedAccessGroup(I);
6907 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"
, 6907, __extension__ __PRETTY_FUNCTION__))
;
6908
6909 unsigned InterleaveFactor = Group->getFactor();
6910 Type *WideVecTy = VectorType::get(ValTy, VF * InterleaveFactor);
6911
6912 // Holds the indices of existing members in an interleaved load group.
6913 // An interleaved store group doesn't need this as it doesn't allow gaps.
6914 SmallVector<unsigned, 4> Indices;
6915 if (isa<LoadInst>(I)) {
6916 for (unsigned i = 0; i < InterleaveFactor; i++)
6917 if (Group->getMember(i))
6918 Indices.push_back(i);
6919 }
6920
6921 // Calculate the cost of the whole interleaved group.
6922 unsigned Cost = TTI.getInterleavedMemoryOpCost(I->getOpcode(), WideVecTy,
6923 Group->getFactor(), Indices,
6924 Group->getAlignment(), AS);
6925
6926 if (Group->isReverse())
6927 Cost += Group->getNumMembers() *
6928 TTI.getShuffleCost(TargetTransformInfo::SK_Reverse, VectorTy, 0);
6929 return Cost;
6930}
6931
6932unsigned LoopVectorizationCostModel::getMemoryInstructionCost(Instruction *I,
6933 unsigned VF) {
6934 // Calculate scalar cost only. Vectorization cost should be ready at this
6935 // moment.
6936 if (VF == 1) {
6937 Type *ValTy = getMemInstValueType(I);
6938 unsigned Alignment = getMemInstAlignment(I);
6939 unsigned AS = getMemInstAddressSpace(I);
6940
6941 return TTI.getAddressComputationCost(ValTy) +
6942 TTI.getMemoryOpCost(I->getOpcode(), ValTy, Alignment, AS, I);
6943 }
6944 return getWideningCost(I, VF);
6945}
6946
6947LoopVectorizationCostModel::VectorizationCostTy
6948LoopVectorizationCostModel::getInstructionCost(Instruction *I, unsigned VF) {
6949 // If we know that this instruction will remain uniform, check the cost of
6950 // the scalar version.
6951 if (isUniformAfterVectorization(I, VF))
6952 VF = 1;
6953
6954 if (VF > 1 && isProfitableToScalarize(I, VF))
6955 return VectorizationCostTy(InstsToScalarize[VF][I], false);
6956
6957 // Forced scalars do not have any scalarization overhead.
6958 if (VF > 1 && ForcedScalars.count(VF) &&
6959 ForcedScalars.find(VF)->second.count(I))
6960 return VectorizationCostTy((getInstructionCost(I, 1).first * VF), false);
6961
6962 Type *VectorTy;
6963 unsigned C = getInstructionCost(I, VF, VectorTy);
6964
6965 bool TypeNotScalarized =
6966 VF > 1 && VectorTy->isVectorTy() && TTI.getNumberOfParts(VectorTy) < VF;
6967 return VectorizationCostTy(C, TypeNotScalarized);
6968}
6969
6970void LoopVectorizationCostModel::setCostBasedWideningDecision(unsigned VF) {
6971 if (VF == 1)
6972 return;
6973 for (BasicBlock *BB : TheLoop->blocks()) {
6974 // For each instruction in the old loop.
6975 for (Instruction &I : *BB) {
6976 Value *Ptr = getPointerOperand(&I);
6977 if (!Ptr)
6978 continue;
6979
6980 if (isa<LoadInst>(&I) && Legal->isUniform(Ptr)) {
6981 // Scalar load + broadcast
6982 unsigned Cost = getUniformMemOpCost(&I, VF);
6983 setWideningDecision(&I, VF, CM_Scalarize, Cost);
6984 continue;
6985 }
6986
6987 // We assume that widening is the best solution when possible.
6988 if (Legal->memoryInstructionCanBeWidened(&I, VF)) {
6989 unsigned Cost = getConsecutiveMemOpCost(&I, VF);
6990 int ConsecutiveStride = Legal->isConsecutivePtr(getPointerOperand(&I));
6991 assert((ConsecutiveStride == 1 || ConsecutiveStride == -1) &&(static_cast <bool> ((ConsecutiveStride == 1 || ConsecutiveStride
== -1) && "Expected consecutive stride.") ? void (0)
: __assert_fail ("(ConsecutiveStride == 1 || ConsecutiveStride == -1) && \"Expected consecutive stride.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6992, __extension__ __PRETTY_FUNCTION__))
6992 "Expected consecutive stride.")(static_cast <bool> ((ConsecutiveStride == 1 || ConsecutiveStride
== -1) && "Expected consecutive stride.") ? void (0)
: __assert_fail ("(ConsecutiveStride == 1 || ConsecutiveStride == -1) && \"Expected consecutive stride.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 6992, __extension__ __PRETTY_FUNCTION__))
;
6993 InstWidening Decision =
6994 ConsecutiveStride == 1 ? CM_Widen : CM_Widen_Reverse;
6995 setWideningDecision(&I, VF, Decision, Cost);
6996 continue;
6997 }
6998
6999 // Choose between Interleaving, Gather/Scatter or Scalarization.
7000 unsigned InterleaveCost = std::numeric_limits<unsigned>::max();
7001 unsigned NumAccesses = 1;
7002 if (Legal->isAccessInterleaved(&I)) {
7003 auto Group = Legal->getInterleavedAccessGroup(&I);
7004 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"
, 7004, __extension__ __PRETTY_FUNCTION__))
;
7005
7006 // Make one decision for the whole group.
7007 if (getWideningDecision(&I, VF) != CM_Unknown)
7008 continue;
7009
7010 NumAccesses = Group->getNumMembers();
7011 InterleaveCost = getInterleaveGroupCost(&I, VF);
7012 }
7013
7014 unsigned GatherScatterCost =
7015 Legal->isLegalGatherOrScatter(&I)
7016 ? getGatherScatterCost(&I, VF) * NumAccesses
7017 : std::numeric_limits<unsigned>::max();
7018
7019 unsigned ScalarizationCost =
7020 getMemInstScalarizationCost(&I, VF) * NumAccesses;
7021
7022 // Choose better solution for the current VF,
7023 // write down this decision and use it during vectorization.
7024 unsigned Cost;
7025 InstWidening Decision;
7026 if (InterleaveCost <= GatherScatterCost &&
7027 InterleaveCost < ScalarizationCost) {
7028 Decision = CM_Interleave;
7029 Cost = InterleaveCost;
7030 } else if (GatherScatterCost < ScalarizationCost) {
7031 Decision = CM_GatherScatter;
7032 Cost = GatherScatterCost;
7033 } else {
7034 Decision = CM_Scalarize;
7035 Cost = ScalarizationCost;
7036 }
7037 // If the instructions belongs to an interleave group, the whole group
7038 // receives the same decision. The whole group receives the cost, but
7039 // the cost will actually be assigned to one instruction.
7040 if (auto Group = Legal->getInterleavedAccessGroup(&I))
7041 setWideningDecision(Group, VF, Decision, Cost);
7042 else
7043 setWideningDecision(&I, VF, Decision, Cost);
7044 }
7045 }
7046
7047 // Make sure that any load of address and any other address computation
7048 // remains scalar unless there is gather/scatter support. This avoids
7049 // inevitable extracts into address registers, and also has the benefit of
7050 // activating LSR more, since that pass can't optimize vectorized
7051 // addresses.
7052 if (TTI.prefersVectorizedAddressing())
7053 return;
7054
7055 // Start with all scalar pointer uses.
7056 SmallPtrSet<Instruction *, 8> AddrDefs;
7057 for (BasicBlock *BB : TheLoop->blocks())
7058 for (Instruction &I : *BB) {
7059 Instruction *PtrDef =
7060 dyn_cast_or_null<Instruction>(getPointerOperand(&I));
7061 if (PtrDef && TheLoop->contains(PtrDef) &&
7062 getWideningDecision(&I, VF) != CM_GatherScatter)
7063 AddrDefs.insert(PtrDef);
7064 }
7065
7066 // Add all instructions used to generate the addresses.
7067 SmallVector<Instruction *, 4> Worklist;
7068 for (auto *I : AddrDefs)
7069 Worklist.push_back(I);
7070 while (!Worklist.empty()) {
7071 Instruction *I = Worklist.pop_back_val();
7072 for (auto &Op : I->operands())
7073 if (auto *InstOp = dyn_cast<Instruction>(Op))
7074 if ((InstOp->getParent() == I->getParent()) && !isa<PHINode>(InstOp) &&
7075 AddrDefs.insert(InstOp).second)
7076 Worklist.push_back(InstOp);
7077 }
7078
7079 for (auto *I : AddrDefs) {
7080 if (isa<LoadInst>(I)) {
7081 // Setting the desired widening decision should ideally be handled in
7082 // by cost functions, but since this involves the task of finding out
7083 // if the loaded register is involved in an address computation, it is
7084 // instead changed here when we know this is the case.
7085 InstWidening Decision = getWideningDecision(I, VF);
7086 if (Decision == CM_Widen || Decision == CM_Widen_Reverse)
7087 // Scalarize a widened load of address.
7088 setWideningDecision(I, VF, CM_Scalarize,
7089 (VF * getMemoryInstructionCost(I, 1)));
7090 else if (auto Group = Legal->getInterleavedAccessGroup(I)) {
7091 // Scalarize an interleave group of address loads.
7092 for (unsigned I = 0; I < Group->getFactor(); ++I) {
7093 if (Instruction *Member = Group->getMember(I))
7094 setWideningDecision(Member, VF, CM_Scalarize,
7095 (VF * getMemoryInstructionCost(Member, 1)));
7096 }
7097 }
7098 } else
7099 // Make sure I gets scalarized and a cost estimate without
7100 // scalarization overhead.
7101 ForcedScalars[VF].insert(I);
7102 }
7103}
7104
7105unsigned LoopVectorizationCostModel::getInstructionCost(Instruction *I,
7106 unsigned VF,
7107 Type *&VectorTy) {
7108 Type *RetTy = I->getType();
7109 if (canTruncateToMinimalBitwidth(I, VF))
7110 RetTy = IntegerType::get(RetTy->getContext(), MinBWs[I]);
7111 VectorTy = isScalarAfterVectorization(I, VF) ? RetTy : ToVectorTy(RetTy, VF);
7112 auto SE = PSE.getSE();
7113
7114 // TODO: We need to estimate the cost of intrinsic calls.
7115 switch (I->getOpcode()) {
7116 case Instruction::GetElementPtr:
7117 // We mark this instruction as zero-cost because the cost of GEPs in
7118 // vectorized code depends on whether the corresponding memory instruction
7119 // is scalarized or not. Therefore, we handle GEPs with the memory
7120 // instruction cost.
7121 return 0;
7122 case Instruction::Br: {
7123 // In cases of scalarized and predicated instructions, there will be VF
7124 // predicated blocks in the vectorized loop. Each branch around these
7125 // blocks requires also an extract of its vector compare i1 element.
7126 bool ScalarPredicatedBB = false;
7127 BranchInst *BI = cast<BranchInst>(I);
7128 if (VF > 1 && BI->isConditional() &&
7129 (PredicatedBBsAfterVectorization.count(BI->getSuccessor(0)) ||
7130 PredicatedBBsAfterVectorization.count(BI->getSuccessor(1))))
7131 ScalarPredicatedBB = true;
7132
7133 if (ScalarPredicatedBB) {
7134 // Return cost for branches around scalarized and predicated blocks.
7135 Type *Vec_i1Ty =
7136 VectorType::get(IntegerType::getInt1Ty(RetTy->getContext()), VF);
7137 return (TTI.getScalarizationOverhead(Vec_i1Ty, false, true) +
7138 (TTI.getCFInstrCost(Instruction::Br) * VF));
7139 } else if (I->getParent() == TheLoop->getLoopLatch() || VF == 1)
7140 // The back-edge branch will remain, as will all scalar branches.
7141 return TTI.getCFInstrCost(Instruction::Br);
7142 else
7143 // This branch will be eliminated by if-conversion.
7144 return 0;
7145 // Note: We currently assume zero cost for an unconditional branch inside
7146 // a predicated block since it will become a fall-through, although we
7147 // may decide in the future to call TTI for all branches.
7148 }
7149 case Instruction::PHI: {
7150 auto *Phi = cast<PHINode>(I);
7151
7152 // First-order recurrences are replaced by vector shuffles inside the loop.
7153 if (VF > 1 && Legal->isFirstOrderRecurrence(Phi))
7154 return TTI.getShuffleCost(TargetTransformInfo::SK_ExtractSubvector,
7155 VectorTy, VF - 1, VectorTy);
7156
7157 // Phi nodes in non-header blocks (not inductions, reductions, etc.) are
7158 // converted into select instructions. We require N - 1 selects per phi
7159 // node, where N is the number of incoming values.
7160 if (VF > 1 && Phi->getParent() != TheLoop->getHeader())
7161 return (Phi->getNumIncomingValues() - 1) *
7162 TTI.getCmpSelInstrCost(
7163 Instruction::Select, ToVectorTy(Phi->getType(), VF),
7164 ToVectorTy(Type::getInt1Ty(Phi->getContext()), VF));
7165
7166 return TTI.getCFInstrCost(Instruction::PHI);
7167 }
7168 case Instruction::UDiv:
7169 case Instruction::SDiv:
7170 case Instruction::URem:
7171 case Instruction::SRem:
7172 // If we have a predicated instruction, it may not be executed for each
7173 // vector lane. Get the scalarization cost and scale this amount by the
7174 // probability of executing the predicated block. If the instruction is not
7175 // predicated, we fall through to the next case.
7176 if (VF > 1 && Legal->isScalarWithPredication(I)) {
7177 unsigned Cost = 0;
7178
7179 // These instructions have a non-void type, so account for the phi nodes
7180 // that we will create. This cost is likely to be zero. The phi node
7181 // cost, if any, should be scaled by the block probability because it
7182 // models a copy at the end of each predicated block.
7183 Cost += VF * TTI.getCFInstrCost(Instruction::PHI);
7184
7185 // The cost of the non-predicated instruction.
7186 Cost += VF * TTI.getArithmeticInstrCost(I->getOpcode(), RetTy);
7187
7188 // The cost of insertelement and extractelement instructions needed for
7189 // scalarization.
7190 Cost += getScalarizationOverhead(I, VF, TTI);
7191
7192 // Scale the cost by the probability of executing the predicated blocks.
7193 // This assumes the predicated block for each vector lane is equally
7194 // likely.
7195 return Cost / getReciprocalPredBlockProb();
7196 }
7197 LLVM_FALLTHROUGH[[clang::fallthrough]];
7198 case Instruction::Add:
7199 case Instruction::FAdd:
7200 case Instruction::Sub:
7201 case Instruction::FSub:
7202 case Instruction::Mul:
7203 case Instruction::FMul:
7204 case Instruction::FDiv:
7205 case Instruction::FRem:
7206 case Instruction::Shl:
7207 case Instruction::LShr:
7208 case Instruction::AShr:
7209 case Instruction::And:
7210 case Instruction::Or:
7211 case Instruction::Xor: {
7212 // Since we will replace the stride by 1 the multiplication should go away.
7213 if (I->getOpcode() == Instruction::Mul && isStrideMul(I, Legal))
7214 return 0;
7215 // Certain instructions can be cheaper to vectorize if they have a constant
7216 // second vector operand. One example of this are shifts on x86.
7217 TargetTransformInfo::OperandValueKind Op1VK =
7218 TargetTransformInfo::OK_AnyValue;
7219 TargetTransformInfo::OperandValueKind Op2VK =
7220 TargetTransformInfo::OK_AnyValue;
7221 TargetTransformInfo::OperandValueProperties Op1VP =
7222 TargetTransformInfo::OP_None;
7223 TargetTransformInfo::OperandValueProperties Op2VP =
7224 TargetTransformInfo::OP_None;
7225 Value *Op2 = I->getOperand(1);
7226
7227 // Check for a splat or for a non uniform vector of constants.
7228 if (isa<ConstantInt>(Op2)) {
7229 ConstantInt *CInt = cast<ConstantInt>(Op2);
7230 if (CInt && CInt->getValue().isPowerOf2())
7231 Op2VP = TargetTransformInfo::OP_PowerOf2;
7232 Op2VK = TargetTransformInfo::OK_UniformConstantValue;
7233 } else if (isa<ConstantVector>(Op2) || isa<ConstantDataVector>(Op2)) {
7234 Op2VK = TargetTransformInfo::OK_NonUniformConstantValue;
7235 Constant *SplatValue = cast<Constant>(Op2)->getSplatValue();
7236 if (SplatValue) {
7237 ConstantInt *CInt = dyn_cast<ConstantInt>(SplatValue);
7238 if (CInt && CInt->getValue().isPowerOf2())
7239 Op2VP = TargetTransformInfo::OP_PowerOf2;
7240 Op2VK = TargetTransformInfo::OK_UniformConstantValue;
7241 }
7242 } else if (Legal->isUniform(Op2)) {
7243 Op2VK = TargetTransformInfo::OK_UniformValue;
7244 }
7245 SmallVector<const Value *, 4> Operands(I->operand_values());
7246 unsigned N = isScalarAfterVectorization(I, VF) ? VF : 1;
7247 return N * TTI.getArithmeticInstrCost(I->getOpcode(), VectorTy, Op1VK,
7248 Op2VK, Op1VP, Op2VP, Operands);
7249 }
7250 case Instruction::Select: {
7251 SelectInst *SI = cast<SelectInst>(I);
7252 const SCEV *CondSCEV = SE->getSCEV(SI->getCondition());
7253 bool ScalarCond = (SE->isLoopInvariant(CondSCEV, TheLoop));
7254 Type *CondTy = SI->getCondition()->getType();
7255 if (!ScalarCond)
7256 CondTy = VectorType::get(CondTy, VF);
7257
7258 return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy, CondTy, I);
7259 }
7260 case Instruction::ICmp:
7261 case Instruction::FCmp: {
7262 Type *ValTy = I->getOperand(0)->getType();
7263 Instruction *Op0AsInstruction = dyn_cast<Instruction>(I->getOperand(0));
7264 if (canTruncateToMinimalBitwidth(Op0AsInstruction, VF))
7265 ValTy = IntegerType::get(ValTy->getContext(), MinBWs[Op0AsInstruction]);
7266 VectorTy = ToVectorTy(ValTy, VF);
7267 return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy, nullptr, I);
7268 }
7269 case Instruction::Store:
7270 case Instruction::Load: {
7271 unsigned Width = VF;
7272 if (Width > 1) {
7273 InstWidening Decision = getWideningDecision(I, Width);
7274 assert(Decision != CM_Unknown &&(static_cast <bool> (Decision != CM_Unknown && "CM decision should be taken at this point"
) ? void (0) : __assert_fail ("Decision != CM_Unknown && \"CM decision should be taken at this point\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7275, __extension__ __PRETTY_FUNCTION__))
7275 "CM decision should be taken at this point")(static_cast <bool> (Decision != CM_Unknown && "CM decision should be taken at this point"
) ? void (0) : __assert_fail ("Decision != CM_Unknown && \"CM decision should be taken at this point\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7275, __extension__ __PRETTY_FUNCTION__))
;
7276 if (Decision == CM_Scalarize)
7277 Width = 1;
7278 }
7279 VectorTy = ToVectorTy(getMemInstValueType(I), Width);
7280 return getMemoryInstructionCost(I, VF);
7281 }
7282 case Instruction::ZExt:
7283 case Instruction::SExt:
7284 case Instruction::FPToUI:
7285 case Instruction::FPToSI:
7286 case Instruction::FPExt:
7287 case Instruction::PtrToInt:
7288 case Instruction::IntToPtr:
7289 case Instruction::SIToFP:
7290 case Instruction::UIToFP:
7291 case Instruction::Trunc:
7292 case Instruction::FPTrunc:
7293 case Instruction::BitCast: {
7294 // We optimize the truncation of induction variables having constant
7295 // integer steps. The cost of these truncations is the same as the scalar
7296 // operation.
7297 if (isOptimizableIVTruncate(I, VF)) {
7298 auto *Trunc = cast<TruncInst>(I);
7299 return TTI.getCastInstrCost(Instruction::Trunc, Trunc->getDestTy(),
7300 Trunc->getSrcTy(), Trunc);
7301 }
7302
7303 Type *SrcScalarTy = I->getOperand(0)->getType();
7304 Type *SrcVecTy =
7305 VectorTy->isVectorTy() ? ToVectorTy(SrcScalarTy, VF) : SrcScalarTy;
7306 if (canTruncateToMinimalBitwidth(I, VF)) {
7307 // This cast is going to be shrunk. This may remove the cast or it might
7308 // turn it into slightly different cast. For example, if MinBW == 16,
7309 // "zext i8 %1 to i32" becomes "zext i8 %1 to i16".
7310 //
7311 // Calculate the modified src and dest types.
7312 Type *MinVecTy = VectorTy;
7313 if (I->getOpcode() == Instruction::Trunc) {
7314 SrcVecTy = smallestIntegerVectorType(SrcVecTy, MinVecTy);
7315 VectorTy =
7316 largestIntegerVectorType(ToVectorTy(I->getType(), VF), MinVecTy);
7317 } else if (I->getOpcode() == Instruction::ZExt ||
7318 I->getOpcode() == Instruction::SExt) {
7319 SrcVecTy = largestIntegerVectorType(SrcVecTy, MinVecTy);
7320 VectorTy =
7321 smallestIntegerVectorType(ToVectorTy(I->getType(), VF), MinVecTy);
7322 }
7323 }
7324
7325 unsigned N = isScalarAfterVectorization(I, VF) ? VF : 1;
7326 return N * TTI.getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy, I);
7327 }
7328 case Instruction::Call: {
7329 bool NeedToScalarize;
7330 CallInst *CI = cast<CallInst>(I);
7331 unsigned CallCost = getVectorCallCost(CI, VF, TTI, TLI, NeedToScalarize);
7332 if (getVectorIntrinsicIDForCall(CI, TLI))
7333 return std::min(CallCost, getVectorIntrinsicCost(CI, VF, TTI, TLI));
7334 return CallCost;
7335 }
7336 default:
7337 // The cost of executing VF copies of the scalar instruction. This opcode
7338 // is unknown. Assume that it is the same as 'mul'.
7339 return VF * TTI.getArithmeticInstrCost(Instruction::Mul, VectorTy) +
7340 getScalarizationOverhead(I, VF, TTI);
7341 } // end of switch.
7342}
7343
7344char LoopVectorize::ID = 0;
7345
7346static const char lv_name[] = "Loop Vectorization";
7347
7348INITIALIZE_PASS_BEGIN(LoopVectorize, LV_NAME, lv_name, false, false)static void *initializeLoopVectorizePassOnce(PassRegistry &
Registry) {
7349INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry);
7350INITIALIZE_PASS_DEPENDENCY(BasicAAWrapperPass)initializeBasicAAWrapperPassPass(Registry);
7351INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
7352INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)initializeGlobalsAAWrapperPassPass(Registry);
7353INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
7354INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)initializeBlockFrequencyInfoWrapperPassPass(Registry);
7355INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
7356INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)initializeScalarEvolutionWrapperPassPass(Registry);
7357INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)initializeLoopInfoWrapperPassPass(Registry);
7358INITIALIZE_PASS_DEPENDENCY(LoopAccessLegacyAnalysis)initializeLoopAccessLegacyAnalysisPass(Registry);
7359INITIALIZE_PASS_DEPENDENCY(DemandedBitsWrapperPass)initializeDemandedBitsWrapperPassPass(Registry);
7360INITIALIZE_PASS_DEPENDENCY(OptimizationRemarkEmitterWrapperPass)initializeOptimizationRemarkEmitterWrapperPassPass(Registry);
7361INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false)PassInfo *PI = new PassInfo( lv_name, "loop-vectorize", &
LoopVectorize::ID, PassInfo::NormalCtor_t(callDefaultCtor<
LoopVectorize>), false, false); Registry.registerPass(*PI,
true); return PI; } static llvm::once_flag InitializeLoopVectorizePassFlag
; void llvm::initializeLoopVectorizePass(PassRegistry &Registry
) { llvm::call_once(InitializeLoopVectorizePassFlag, initializeLoopVectorizePassOnce
, std::ref(Registry)); }
7362
7363namespace llvm {
7364
7365Pass *createLoopVectorizePass(bool NoUnrolling, bool AlwaysVectorize) {
7366 return new LoopVectorize(NoUnrolling, AlwaysVectorize);
7367}
7368
7369} // end namespace llvm
7370
7371bool LoopVectorizationCostModel::isConsecutiveLoadOrStore(Instruction *Inst) {
7372 // Check if the pointer operand of a load or store instruction is
7373 // consecutive.
7374 if (auto *Ptr = getPointerOperand(Inst))
7375 return Legal->isConsecutivePtr(Ptr);
7376 return false;
7377}
7378
7379void LoopVectorizationCostModel::collectValuesToIgnore() {
7380 // Ignore ephemeral values.
7381 CodeMetrics::collectEphemeralValues(TheLoop, AC, ValuesToIgnore);
7382
7383 // Ignore type-promoting instructions we identified during reduction
7384 // detection.
7385 for (auto &Reduction : *Legal->getReductionVars()) {
7386 RecurrenceDescriptor &RedDes = Reduction.second;
7387 SmallPtrSetImpl<Instruction *> &Casts = RedDes.getCastInsts();
7388 VecValuesToIgnore.insert(Casts.begin(), Casts.end());
7389 }
7390 // Ignore type-casting instructions we identified during induction
7391 // detection.
7392 for (auto &Induction : *Legal->getInductionVars()) {
7393 InductionDescriptor &IndDes = Induction.second;
7394 const SmallVectorImpl<Instruction *> &Casts = IndDes.getCastInsts();
7395 VecValuesToIgnore.insert(Casts.begin(), Casts.end());
7396 }
7397}
7398
7399VectorizationFactor
7400LoopVectorizationPlanner::plan(bool OptForSize, unsigned UserVF) {
7401 // Width 1 means no vectorize, cost 0 means uncomputed cost.
7402 const VectorizationFactor NoVectorization = {1U, 0U};
7403 Optional<unsigned> MaybeMaxVF = CM.computeMaxVF(OptForSize);
7404 if (!MaybeMaxVF.hasValue()) // Cases considered too costly to vectorize.
7405 return NoVectorization;
7406
7407 if (UserVF) {
7408 DEBUG(dbgs() << "LV: Using user VF " << UserVF << ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Using user VF " <<
UserVF << ".\n"; } } while (false)
;
7409 assert(isPowerOf2_32(UserVF) && "VF needs to be a power of two")(static_cast <bool> (isPowerOf2_32(UserVF) && "VF needs to be a power of two"
) ? void (0) : __assert_fail ("isPowerOf2_32(UserVF) && \"VF needs to be a power of two\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7409, __extension__ __PRETTY_FUNCTION__))
;
7410 // Collect the instructions (and their associated costs) that will be more
7411 // profitable to scalarize.
7412 CM.selectUserVectorizationFactor(UserVF);
7413 buildVPlans(UserVF, UserVF);
7414 DEBUG(printPlans(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { printPlans(dbgs()); } } while (false)
;
7415 return {UserVF, 0};
7416 }
7417
7418 unsigned MaxVF = MaybeMaxVF.getValue();
7419 assert(MaxVF != 0 && "MaxVF is zero.")(static_cast <bool> (MaxVF != 0 && "MaxVF is zero."
) ? void (0) : __assert_fail ("MaxVF != 0 && \"MaxVF is zero.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7419, __extension__ __PRETTY_FUNCTION__))
;
7420
7421 for (unsigned VF = 1; VF <= MaxVF; VF *= 2) {
7422 // Collect Uniform and Scalar instructions after vectorization with VF.
7423 CM.collectUniformsAndScalars(VF);
7424
7425 // Collect the instructions (and their associated costs) that will be more
7426 // profitable to scalarize.
7427 if (VF > 1)
7428 CM.collectInstsToScalarize(VF);
7429 }
7430
7431 buildVPlans(1, MaxVF);
7432 DEBUG(printPlans(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { printPlans(dbgs()); } } while (false)
;
7433 if (MaxVF == 1)
7434 return NoVectorization;
7435
7436 // Select the optimal vectorization factor.
7437 return CM.selectVectorizationFactor(MaxVF);
7438}
7439
7440void LoopVectorizationPlanner::setBestPlan(unsigned VF, unsigned UF) {
7441 DEBUG(dbgs() << "Setting best plan to VF=" << VF << ", UF=" << UF << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "Setting best plan to VF="
<< VF << ", UF=" << UF << '\n'; } } while
(false)
;
7442 BestVF = VF;
7443 BestUF = UF;
7444
7445 erase_if(VPlans, [VF](const VPlanPtr &Plan) {
7446 return !Plan->hasVF(VF);
7447 });
7448 assert(VPlans.size() == 1 && "Best VF has not a single VPlan.")(static_cast <bool> (VPlans.size() == 1 && "Best VF has not a single VPlan."
) ? void (0) : __assert_fail ("VPlans.size() == 1 && \"Best VF has not a single VPlan.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7448, __extension__ __PRETTY_FUNCTION__))
;
7449}
7450
7451void LoopVectorizationPlanner::executePlan(InnerLoopVectorizer &ILV,
7452 DominatorTree *DT) {
7453 // Perform the actual loop transformation.
7454
7455 // 1. Create a new empty loop. Unlink the old loop and connect the new one.
7456 VPCallbackILV CallbackILV(ILV);
7457
7458 VPTransformState State{BestVF, BestUF, LI,
7459 DT, ILV.Builder, ILV.VectorLoopValueMap,
7460 &ILV, CallbackILV};
7461 State.CFG.PrevBB = ILV.createVectorizedLoopSkeleton();
7462
7463 //===------------------------------------------------===//
7464 //
7465 // Notice: any optimization or new instruction that go
7466 // into the code below should also be implemented in
7467 // the cost-model.
7468 //
7469 //===------------------------------------------------===//
7470
7471 // 2. Copy and widen instructions from the old loop into the new loop.
7472 assert(VPlans.size() == 1 && "Not a single VPlan to execute.")(static_cast <bool> (VPlans.size() == 1 && "Not a single VPlan to execute."
) ? void (0) : __assert_fail ("VPlans.size() == 1 && \"Not a single VPlan to execute.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7472, __extension__ __PRETTY_FUNCTION__))
;
7473 VPlans.front()->execute(&State);
7474
7475 // 3. Fix the vectorized code: take care of header phi's, live-outs,
7476 // predication, updating analyses.
7477 ILV.fixVectorizedLoop();
7478}
7479
7480void LoopVectorizationPlanner::collectTriviallyDeadInstructions(
7481 SmallPtrSetImpl<Instruction *> &DeadInstructions) {
7482 BasicBlock *Latch = OrigLoop->getLoopLatch();
7483
7484 // We create new control-flow for the vectorized loop, so the original
7485 // condition will be dead after vectorization if it's only used by the
7486 // branch.
7487 auto *Cmp = dyn_cast<Instruction>(Latch->getTerminator()->getOperand(0));
7488 if (Cmp && Cmp->hasOneUse())
7489 DeadInstructions.insert(Cmp);
7490
7491 // We create new "steps" for induction variable updates to which the original
7492 // induction variables map. An original update instruction will be dead if
7493 // all its users except the induction variable are dead.
7494 for (auto &Induction : *Legal->getInductionVars()) {
7495 PHINode *Ind = Induction.first;
7496 auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch));
7497 if (llvm::all_of(IndUpdate->users(), [&](User *U) -> bool {
7498 return U == Ind || DeadInstructions.count(cast<Instruction>(U));
7499 }))
7500 DeadInstructions.insert(IndUpdate);
7501
7502 // We record as "Dead" also the type-casting instructions we had identified
7503 // during induction analysis. We don't need any handling for them in the
7504 // vectorized loop because we have proven that, under a proper runtime
7505 // test guarding the vectorized loop, the value of the phi, and the casted
7506 // value of the phi, are the same. The last instruction in this casting chain
7507 // will get its scalar/vector/widened def from the scalar/vector/widened def
7508 // of the respective phi node. Any other casts in the induction def-use chain
7509 // have no other uses outside the phi update chain, and will be ignored.
7510 InductionDescriptor &IndDes = Induction.second;
7511 const SmallVectorImpl<Instruction *> &Casts = IndDes.getCastInsts();
7512 DeadInstructions.insert(Casts.begin(), Casts.end());
7513 }
7514}
7515
7516Value *InnerLoopUnroller::reverseVector(Value *Vec) { return Vec; }
7517
7518Value *InnerLoopUnroller::getBroadcastInstrs(Value *V) { return V; }
7519
7520Value *InnerLoopUnroller::getStepVector(Value *Val, int StartIdx, Value *Step,
7521 Instruction::BinaryOps BinOp) {
7522 // When unrolling and the VF is 1, we only need to add a simple scalar.
7523 Type *Ty = Val->getType();
7524 assert(!Ty->isVectorTy() && "Val must be a scalar")(static_cast <bool> (!Ty->isVectorTy() && "Val must be a scalar"
) ? void (0) : __assert_fail ("!Ty->isVectorTy() && \"Val must be a scalar\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7524, __extension__ __PRETTY_FUNCTION__))
;
7525
7526 if (Ty->isFloatingPointTy()) {
7527 Constant *C = ConstantFP::get(Ty, (double)StartIdx);
7528
7529 // Floating point operations had to be 'fast' to enable the unrolling.
7530 Value *MulOp = addFastMathFlag(Builder.CreateFMul(C, Step));
7531 return addFastMathFlag(Builder.CreateBinOp(BinOp, Val, MulOp));
7532 }
7533 Constant *C = ConstantInt::get(Ty, StartIdx);
7534 return Builder.CreateAdd(Val, Builder.CreateMul(C, Step), "induction");
7535}
7536
7537static void AddRuntimeUnrollDisableMetaData(Loop *L) {
7538 SmallVector<Metadata *, 4> MDs;
7539 // Reserve first location for self reference to the LoopID metadata node.
7540 MDs.push_back(nullptr);
7541 bool IsUnrollMetadata = false;
7542 MDNode *LoopID = L->getLoopID();
7543 if (LoopID) {
7544 // First find existing loop unrolling disable metadata.
7545 for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
7546 auto *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
7547 if (MD) {
7548 const auto *S = dyn_cast<MDString>(MD->getOperand(0));
7549 IsUnrollMetadata =
7550 S && S->getString().startswith("llvm.loop.unroll.disable");
7551 }
7552 MDs.push_back(LoopID->getOperand(i));
7553 }
7554 }
7555
7556 if (!IsUnrollMetadata) {
7557 // Add runtime unroll disable metadata.
7558 LLVMContext &Context = L->getHeader()->getContext();
7559 SmallVector<Metadata *, 1> DisableOperands;
7560 DisableOperands.push_back(
7561 MDString::get(Context, "llvm.loop.unroll.runtime.disable"));
7562 MDNode *DisableNode = MDNode::get(Context, DisableOperands);
7563 MDs.push_back(DisableNode);
7564 MDNode *NewLoopID = MDNode::get(Context, MDs);
7565 // Set operand 0 to refer to the loop id itself.
7566 NewLoopID->replaceOperandWith(0, NewLoopID);
7567 L->setLoopID(NewLoopID);
7568 }
7569}
7570
7571bool LoopVectorizationPlanner::getDecisionAndClampRange(
7572 const std::function<bool(unsigned)> &Predicate, VFRange &Range) {
7573 assert(Range.End > Range.Start && "Trying to test an empty VF range.")(static_cast <bool> (Range.End > Range.Start &&
"Trying to test an empty VF range.") ? void (0) : __assert_fail
("Range.End > Range.Start && \"Trying to test an empty VF range.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7573, __extension__ __PRETTY_FUNCTION__))
;
7574 bool PredicateAtRangeStart = Predicate(Range.Start);
7575
7576 for (unsigned TmpVF = Range.Start * 2; TmpVF < Range.End; TmpVF *= 2)
7577 if (Predicate(TmpVF) != PredicateAtRangeStart) {
7578 Range.End = TmpVF;
7579 break;
7580 }
7581
7582 return PredicateAtRangeStart;
7583}
7584
7585/// Build VPlans for the full range of feasible VF's = {\p MinVF, 2 * \p MinVF,
7586/// 4 * \p MinVF, ..., \p MaxVF} by repeatedly building a VPlan for a sub-range
7587/// of VF's starting at a given VF and extending it as much as possible. Each
7588/// vectorization decision can potentially shorten this sub-range during
7589/// buildVPlan().
7590void LoopVectorizationPlanner::buildVPlans(unsigned MinVF, unsigned MaxVF) {
7591
7592 // Collect conditions feeding internal conditional branches; they need to be
7593 // represented in VPlan for it to model masking.
7594 SmallPtrSet<Value *, 1> NeedDef;
7595
7596 auto *Latch = OrigLoop->getLoopLatch();
7597 for (BasicBlock *BB : OrigLoop->blocks()) {
7598 if (BB == Latch)
7599 continue;
7600 BranchInst *Branch = dyn_cast<BranchInst>(BB->getTerminator());
7601 if (Branch && Branch->isConditional())
7602 NeedDef.insert(Branch->getCondition());
7603 }
7604
7605 for (unsigned VF = MinVF; VF < MaxVF + 1;) {
7606 VFRange SubRange = {VF, MaxVF + 1};
7607 VPlans.push_back(buildVPlan(SubRange, NeedDef));
7608 VF = SubRange.End;
7609 }
7610}
7611
7612VPValue *LoopVectorizationPlanner::createEdgeMask(BasicBlock *Src,
7613 BasicBlock *Dst,
7614 VPlanPtr &Plan) {
7615 assert(is_contained(predecessors(Dst), Src) && "Invalid edge")(static_cast <bool> (is_contained(predecessors(Dst), Src
) && "Invalid edge") ? void (0) : __assert_fail ("is_contained(predecessors(Dst), Src) && \"Invalid edge\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7615, __extension__ __PRETTY_FUNCTION__))
;
7616
7617 // Look for cached value.
7618 std::pair<BasicBlock *, BasicBlock *> Edge(Src, Dst);
7619 EdgeMaskCacheTy::iterator ECEntryIt = EdgeMaskCache.find(Edge);
7620 if (ECEntryIt != EdgeMaskCache.end())
7621 return ECEntryIt->second;
7622
7623 VPValue *SrcMask = createBlockInMask(Src, Plan);
7624
7625 // The terminator has to be a branch inst!
7626 BranchInst *BI = dyn_cast<BranchInst>(Src->getTerminator());
7627 assert(BI && "Unexpected terminator found")(static_cast <bool> (BI && "Unexpected terminator found"
) ? void (0) : __assert_fail ("BI && \"Unexpected terminator found\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7627, __extension__ __PRETTY_FUNCTION__))
;
7628
7629 if (!BI->isConditional())
7630 return EdgeMaskCache[Edge] = SrcMask;
7631
7632 VPValue *EdgeMask = Plan->getVPValue(BI->getCondition());
7633 assert(EdgeMask && "No Edge Mask found for condition")(static_cast <bool> (EdgeMask && "No Edge Mask found for condition"
) ? void (0) : __assert_fail ("EdgeMask && \"No Edge Mask found for condition\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7633, __extension__ __PRETTY_FUNCTION__))
;
7634
7635 if (BI->getSuccessor(0) != Dst)
7636 EdgeMask = Builder.createNot(EdgeMask);
7637
7638 if (SrcMask) // Otherwise block in-mask is all-one, no need to AND.
7639 EdgeMask = Builder.createAnd(EdgeMask, SrcMask);
7640
7641 return EdgeMaskCache[Edge] = EdgeMask;
7642}
7643
7644VPValue *LoopVectorizationPlanner::createBlockInMask(BasicBlock *BB,
7645 VPlanPtr &Plan) {
7646 assert(OrigLoop->contains(BB) && "Block is not a part of a loop")(static_cast <bool> (OrigLoop->contains(BB) &&
"Block is not a part of a loop") ? void (0) : __assert_fail (
"OrigLoop->contains(BB) && \"Block is not a part of a loop\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7646, __extension__ __PRETTY_FUNCTION__))
;
7647
7648 // Look for cached value.
7649 BlockMaskCacheTy::iterator BCEntryIt = BlockMaskCache.find(BB);
7650 if (BCEntryIt != BlockMaskCache.end())
7651 return BCEntryIt->second;
7652
7653 // All-one mask is modelled as no-mask following the convention for masked
7654 // load/store/gather/scatter. Initialize BlockMask to no-mask.
7655 VPValue *BlockMask = nullptr;
7656
7657 // Loop incoming mask is all-one.
7658 if (OrigLoop->getHeader() == BB)
7659 return BlockMaskCache[BB] = BlockMask;
7660
7661 // This is the block mask. We OR all incoming edges.
7662 for (auto *Predecessor : predecessors(BB)) {
7663 VPValue *EdgeMask = createEdgeMask(Predecessor, BB, Plan);
7664 if (!EdgeMask) // Mask of predecessor is all-one so mask of block is too.
7665 return BlockMaskCache[BB] = EdgeMask;
7666
7667 if (!BlockMask) { // BlockMask has its initialized nullptr value.
7668 BlockMask = EdgeMask;
7669 continue;
7670 }
7671
7672 BlockMask = Builder.createOr(BlockMask, EdgeMask);
7673 }
7674
7675 return BlockMaskCache[BB] = BlockMask;
7676}
7677
7678VPInterleaveRecipe *
7679LoopVectorizationPlanner::tryToInterleaveMemory(Instruction *I,
7680 VFRange &Range) {
7681 const InterleaveGroup *IG = Legal->getInterleavedAccessGroup(I);
7682 if (!IG)
7683 return nullptr;
7684
7685 // Now check if IG is relevant for VF's in the given range.
7686 auto isIGMember = [&](Instruction *I) -> std::function<bool(unsigned)> {
7687 return [=](unsigned VF) -> bool {
7688 return (VF >= 2 && // Query is illegal for VF == 1
7689 CM.getWideningDecision(I, VF) ==
7690 LoopVectorizationCostModel::CM_Interleave);
7691 };
7692 };
7693 if (!getDecisionAndClampRange(isIGMember(I), Range))
7694 return nullptr;
7695
7696 // I is a member of an InterleaveGroup for VF's in the (possibly trimmed)
7697 // range. If it's the primary member of the IG construct a VPInterleaveRecipe.
7698 // Otherwise, it's an adjunct member of the IG, do not construct any Recipe.
7699 assert(I == IG->getInsertPos() &&(static_cast <bool> (I == IG->getInsertPos() &&
"Generating a recipe for an adjunct member of an interleave group"
) ? void (0) : __assert_fail ("I == IG->getInsertPos() && \"Generating a recipe for an adjunct member of an interleave group\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7700, __extension__ __PRETTY_FUNCTION__))
7700 "Generating a recipe for an adjunct member of an interleave group")(static_cast <bool> (I == IG->getInsertPos() &&
"Generating a recipe for an adjunct member of an interleave group"
) ? void (0) : __assert_fail ("I == IG->getInsertPos() && \"Generating a recipe for an adjunct member of an interleave group\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7700, __extension__ __PRETTY_FUNCTION__))
;
7701
7702 return new VPInterleaveRecipe(IG);
7703}
7704
7705VPWidenMemoryInstructionRecipe *
7706LoopVectorizationPlanner::tryToWidenMemory(Instruction *I, VFRange &Range,
7707 VPlanPtr &Plan) {
7708 if (!isa<LoadInst>(I) && !isa<StoreInst>(I))
7709 return nullptr;
7710
7711 auto willWiden = [&](unsigned VF) -> bool {
7712 if (VF == 1)
7713 return false;
7714 if (CM.isScalarAfterVectorization(I, VF) ||
7715 CM.isProfitableToScalarize(I, VF))
7716 return false;
7717 LoopVectorizationCostModel::InstWidening Decision =
7718 CM.getWideningDecision(I, VF);
7719 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"
, 7720, __extension__ __PRETTY_FUNCTION__))
7720 "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"
, 7720, __extension__ __PRETTY_FUNCTION__))
;
7721 assert(Decision != LoopVectorizationCostModel::CM_Interleave &&(static_cast <bool> (Decision != LoopVectorizationCostModel
::CM_Interleave && "Interleave memory opportunity should be caught earlier."
) ? void (0) : __assert_fail ("Decision != LoopVectorizationCostModel::CM_Interleave && \"Interleave memory opportunity should be caught earlier.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7722, __extension__ __PRETTY_FUNCTION__))
7722 "Interleave memory opportunity should be caught earlier.")(static_cast <bool> (Decision != LoopVectorizationCostModel
::CM_Interleave && "Interleave memory opportunity should be caught earlier."
) ? void (0) : __assert_fail ("Decision != LoopVectorizationCostModel::CM_Interleave && \"Interleave memory opportunity should be caught earlier.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7722, __extension__ __PRETTY_FUNCTION__))
;
7723 return Decision != LoopVectorizationCostModel::CM_Scalarize;
7724 };
7725
7726 if (!getDecisionAndClampRange(willWiden, Range))
7727 return nullptr;
7728
7729 VPValue *Mask = nullptr;
7730 if (Legal->isMaskRequired(I))
7731 Mask = createBlockInMask(I->getParent(), Plan);
7732
7733 return new VPWidenMemoryInstructionRecipe(*I, Mask);
7734}
7735
7736VPWidenIntOrFpInductionRecipe *
7737LoopVectorizationPlanner::tryToOptimizeInduction(Instruction *I,
7738 VFRange &Range) {
7739 if (PHINode *Phi = dyn_cast<PHINode>(I)) {
7740 // Check if this is an integer or fp induction. If so, build the recipe that
7741 // produces its scalar and vector values.
7742 InductionDescriptor II = Legal->getInductionVars()->lookup(Phi);
7743 if (II.getKind() == InductionDescriptor::IK_IntInduction ||
7744 II.getKind() == InductionDescriptor::IK_FpInduction)
7745 return new VPWidenIntOrFpInductionRecipe(Phi);
7746
7747 return nullptr;
7748 }
7749
7750 // Optimize the special case where the source is a constant integer
7751 // induction variable. Notice that we can only optimize the 'trunc' case
7752 // because (a) FP conversions lose precision, (b) sext/zext may wrap, and
7753 // (c) other casts depend on pointer size.
7754
7755 // Determine whether \p K is a truncation based on an induction variable that
7756 // can be optimized.
7757 auto isOptimizableIVTruncate =
7758 [&](Instruction *K) -> std::function<bool(unsigned)> {
7759 return
7760 [=](unsigned VF) -> bool { return CM.isOptimizableIVTruncate(K, VF); };
7761 };
7762
7763 if (isa<TruncInst>(I) &&
7764 getDecisionAndClampRange(isOptimizableIVTruncate(I), Range))
7765 return new VPWidenIntOrFpInductionRecipe(cast<PHINode>(I->getOperand(0)),
7766 cast<TruncInst>(I));
7767 return nullptr;
7768}
7769
7770VPBlendRecipe *
7771LoopVectorizationPlanner::tryToBlend(Instruction *I, VPlanPtr &Plan) {
7772 PHINode *Phi = dyn_cast<PHINode>(I);
7773 if (!Phi || Phi->getParent() == OrigLoop->getHeader())
7774 return nullptr;
7775
7776 // We know that all PHIs in non-header blocks are converted into selects, so
7777 // we don't have to worry about the insertion order and we can just use the
7778 // builder. At this point we generate the predication tree. There may be
7779 // duplications since this is a simple recursive scan, but future
7780 // optimizations will clean it up.
7781
7782 SmallVector<VPValue *, 2> Masks;
7783 unsigned NumIncoming = Phi->getNumIncomingValues();
7784 for (unsigned In = 0; In < NumIncoming; In++) {
7785 VPValue *EdgeMask =
7786 createEdgeMask(Phi->getIncomingBlock(In), Phi->getParent(), Plan);
7787 assert((EdgeMask || NumIncoming == 1) &&(static_cast <bool> ((EdgeMask || NumIncoming == 1) &&
"Multiple predecessors with one having a full mask") ? void (
0) : __assert_fail ("(EdgeMask || NumIncoming == 1) && \"Multiple predecessors with one having a full mask\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7788, __extension__ __PRETTY_FUNCTION__))
7788 "Multiple predecessors with one having a full mask")(static_cast <bool> ((EdgeMask || NumIncoming == 1) &&
"Multiple predecessors with one having a full mask") ? void (
0) : __assert_fail ("(EdgeMask || NumIncoming == 1) && \"Multiple predecessors with one having a full mask\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7788, __extension__ __PRETTY_FUNCTION__))
;
7789 if (EdgeMask)
7790 Masks.push_back(EdgeMask);
7791 }
7792 return new VPBlendRecipe(Phi, Masks);
7793}
7794
7795bool LoopVectorizationPlanner::tryToWiden(Instruction *I, VPBasicBlock *VPBB,
7796 VFRange &Range) {
7797 if (Legal->isScalarWithPredication(I))
7798 return false;
7799
7800 auto IsVectorizableOpcode = [](unsigned Opcode) {
7801 switch (Opcode) {
7802 case Instruction::Add:
7803 case Instruction::And:
7804 case Instruction::AShr:
7805 case Instruction::BitCast:
7806 case Instruction::Br:
7807 case Instruction::Call:
7808 case Instruction::FAdd:
7809 case Instruction::FCmp:
7810 case Instruction::FDiv:
7811 case Instruction::FMul:
7812 case Instruction::FPExt:
7813 case Instruction::FPToSI:
7814 case Instruction::FPToUI:
7815 case Instruction::FPTrunc:
7816 case Instruction::FRem:
7817 case Instruction::FSub:
7818 case Instruction::GetElementPtr:
7819 case Instruction::ICmp:
7820 case Instruction::IntToPtr:
7821 case Instruction::Load:
7822 case Instruction::LShr:
7823 case Instruction::Mul:
7824 case Instruction::Or:
7825 case Instruction::PHI:
7826 case Instruction::PtrToInt:
7827 case Instruction::SDiv:
7828 case Instruction::Select:
7829 case Instruction::SExt:
7830 case Instruction::Shl:
7831 case Instruction::SIToFP:
7832 case Instruction::SRem:
7833 case Instruction::Store:
7834 case Instruction::Sub:
7835 case Instruction::Trunc:
7836 case Instruction::UDiv:
7837 case Instruction::UIToFP:
7838 case Instruction::URem:
7839 case Instruction::Xor:
7840 case Instruction::ZExt:
7841 return true;
7842 }
7843 return false;
7844 };
7845
7846 if (!IsVectorizableOpcode(I->getOpcode()))
7847 return false;
7848
7849 if (CallInst *CI = dyn_cast<CallInst>(I)) {
7850 Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
7851 if (ID && (ID == Intrinsic::assume || ID == Intrinsic::lifetime_end ||
7852 ID == Intrinsic::lifetime_start || ID == Intrinsic::sideeffect))
7853 return false;
7854 }
7855
7856 auto willWiden = [&](unsigned VF) -> bool {
7857 if (!isa<PHINode>(I) && (CM.isScalarAfterVectorization(I, VF) ||
7858 CM.isProfitableToScalarize(I, VF)))
7859 return false;
7860 if (CallInst *CI = dyn_cast<CallInst>(I)) {
7861 Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
7862 // The following case may be scalarized depending on the VF.
7863 // The flag shows whether we use Intrinsic or a usual Call for vectorized
7864 // version of the instruction.
7865 // Is it beneficial to perform intrinsic call compared to lib call?
7866 bool NeedToScalarize;
7867 unsigned CallCost = getVectorCallCost(CI, VF, *TTI, TLI, NeedToScalarize);
7868 bool UseVectorIntrinsic =
7869 ID && getVectorIntrinsicCost(CI, VF, *TTI, TLI) <= CallCost;
7870 return UseVectorIntrinsic || !NeedToScalarize;
7871 }
7872 if (isa<LoadInst>(I) || isa<StoreInst>(I)) {
7873 assert(CM.getWideningDecision(I, VF) ==(static_cast <bool> (CM.getWideningDecision(I, VF) == LoopVectorizationCostModel
::CM_Scalarize && "Memory widening decisions should have been taken care by now"
) ? void (0) : __assert_fail ("CM.getWideningDecision(I, VF) == LoopVectorizationCostModel::CM_Scalarize && \"Memory widening decisions should have been taken care by now\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7875, __extension__ __PRETTY_FUNCTION__))
7874 LoopVectorizationCostModel::CM_Scalarize &&(static_cast <bool> (CM.getWideningDecision(I, VF) == LoopVectorizationCostModel
::CM_Scalarize && "Memory widening decisions should have been taken care by now"
) ? void (0) : __assert_fail ("CM.getWideningDecision(I, VF) == LoopVectorizationCostModel::CM_Scalarize && \"Memory widening decisions should have been taken care by now\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7875, __extension__ __PRETTY_FUNCTION__))
7875 "Memory widening decisions should have been taken care by now")(static_cast <bool> (CM.getWideningDecision(I, VF) == LoopVectorizationCostModel
::CM_Scalarize && "Memory widening decisions should have been taken care by now"
) ? void (0) : __assert_fail ("CM.getWideningDecision(I, VF) == LoopVectorizationCostModel::CM_Scalarize && \"Memory widening decisions should have been taken care by now\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7875, __extension__ __PRETTY_FUNCTION__))
;
7876 return false;
7877 }
7878 return true;
7879 };
7880
7881 if (!getDecisionAndClampRange(willWiden, Range))
7882 return false;
7883
7884 // Success: widen this instruction. We optimize the common case where
7885 // consecutive instructions can be represented by a single recipe.
7886 if (!VPBB->empty()) {
7887 VPWidenRecipe *LastWidenRecipe = dyn_cast<VPWidenRecipe>(&VPBB->back());
7888 if (LastWidenRecipe && LastWidenRecipe->appendInstruction(I))
7889 return true;
7890 }
7891
7892 VPBB->appendRecipe(new VPWidenRecipe(I));
7893 return true;
7894}
7895
7896VPBasicBlock *LoopVectorizationPlanner::handleReplication(
7897 Instruction *I, VFRange &Range, VPBasicBlock *VPBB,
7898 DenseMap<Instruction *, VPReplicateRecipe *> &PredInst2Recipe,
7899 VPlanPtr &Plan) {
7900 bool IsUniform = getDecisionAndClampRange(
7901 [&](unsigned VF) { return CM.isUniformAfterVectorization(I, VF); },
7902 Range);
7903
7904 bool IsPredicated = Legal->isScalarWithPredication(I);
7905 auto *Recipe = new VPReplicateRecipe(I, IsUniform, IsPredicated);
7906
7907 // Find if I uses a predicated instruction. If so, it will use its scalar
7908 // value. Avoid hoisting the insert-element which packs the scalar value into
7909 // a vector value, as that happens iff all users use the vector value.
7910 for (auto &Op : I->operands())
7911 if (auto *PredInst = dyn_cast<Instruction>(Op))
7912 if (PredInst2Recipe.find(PredInst) != PredInst2Recipe.end())
7913 PredInst2Recipe[PredInst]->setAlsoPack(false);
7914
7915 // Finalize the recipe for Instr, first if it is not predicated.
7916 if (!IsPredicated) {
7917 DEBUG(dbgs() << "LV: Scalarizing:" << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Scalarizing:" <<
*I << "\n"; } } while (false)
;
7918 VPBB->appendRecipe(Recipe);
7919 return VPBB;
7920 }
7921 DEBUG(dbgs() << "LV: Scalarizing and predicating:" << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Scalarizing and predicating:"
<< *I << "\n"; } } while (false)
;
7922 assert(VPBB->getSuccessors().empty() &&(static_cast <bool> (VPBB->getSuccessors().empty() &&
"VPBB has successors when handling predicated replication.")
? void (0) : __assert_fail ("VPBB->getSuccessors().empty() && \"VPBB has successors when handling predicated replication.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7923, __extension__ __PRETTY_FUNCTION__))
7923 "VPBB has successors when handling predicated replication.")(static_cast <bool> (VPBB->getSuccessors().empty() &&
"VPBB has successors when handling predicated replication.")
? void (0) : __assert_fail ("VPBB->getSuccessors().empty() && \"VPBB has successors when handling predicated replication.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7923, __extension__ __PRETTY_FUNCTION__))
;
7924 // Record predicated instructions for above packing optimizations.
7925 PredInst2Recipe[I] = Recipe;
7926 VPBlockBase *Region =
7927 VPBB->setOneSuccessor(createReplicateRegion(I, Recipe, Plan));
7928 return cast<VPBasicBlock>(Region->setOneSuccessor(new VPBasicBlock()));
7929}
7930
7931VPRegionBlock *
7932LoopVectorizationPlanner::createReplicateRegion(Instruction *Instr,
7933 VPRecipeBase *PredRecipe,
7934 VPlanPtr &Plan) {
7935 // Instructions marked for predication are replicated and placed under an
7936 // if-then construct to prevent side-effects.
7937
7938 // Generate recipes to compute the block mask for this region.
7939 VPValue *BlockInMask = createBlockInMask(Instr->getParent(), Plan);
7940
7941 // Build the triangular if-then region.
7942 std::string RegionName = (Twine("pred.") + Instr->getOpcodeName()).str();
7943 assert(Instr->getParent() && "Predicated instruction not in any basic block")(static_cast <bool> (Instr->getParent() && "Predicated instruction not in any basic block"
) ? void (0) : __assert_fail ("Instr->getParent() && \"Predicated instruction not in any basic block\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 7943, __extension__ __PRETTY_FUNCTION__))
;
7944 auto *BOMRecipe = new VPBranchOnMaskRecipe(BlockInMask);
7945 auto *Entry = new VPBasicBlock(Twine(RegionName) + ".entry", BOMRecipe);
7946 auto *PHIRecipe =
7947 Instr->getType()->isVoidTy() ? nullptr : new VPPredInstPHIRecipe(Instr);
7948 auto *Exit = new VPBasicBlock(Twine(RegionName) + ".continue", PHIRecipe);
7949 auto *Pred = new VPBasicBlock(Twine(RegionName) + ".if", PredRecipe);
7950 VPRegionBlock *Region = new VPRegionBlock(Entry, Exit, RegionName, true);
7951
7952 // Note: first set Entry as region entry and then connect successors starting
7953 // from it in order, to propagate the "parent" of each VPBasicBlock.
7954 Entry->setTwoSuccessors(Pred, Exit);
7955 Pred->setOneSuccessor(Exit);
7956
7957 return Region;
7958}
7959
7960LoopVectorizationPlanner::VPlanPtr
7961LoopVectorizationPlanner::buildVPlan(VFRange &Range,
7962 const SmallPtrSetImpl<Value *> &NeedDef) {
7963 EdgeMaskCache.clear();
7964 BlockMaskCache.clear();
7965 DenseMap<Instruction *, Instruction *> &SinkAfter = Legal->getSinkAfter();
7966 DenseMap<Instruction *, Instruction *> SinkAfterInverse;
7967
7968 // Collect instructions from the original loop that will become trivially dead
7969 // in the vectorized loop. We don't need to vectorize these instructions. For
7970 // example, original induction update instructions can become dead because we
7971 // separately emit induction "steps" when generating code for the new loop.
7972 // Similarly, we create a new latch condition when setting up the structure
7973 // of the new loop, so the old one can become dead.
7974 SmallPtrSet<Instruction *, 4> DeadInstructions;
7975 collectTriviallyDeadInstructions(DeadInstructions);
7976
7977 // Hold a mapping from predicated instructions to their recipes, in order to
7978 // fix their AlsoPack behavior if a user is determined to replicate and use a
7979 // scalar instead of vector value.
7980 DenseMap<Instruction *, VPReplicateRecipe *> PredInst2Recipe;
7981
7982 // Create a dummy pre-entry VPBasicBlock to start building the VPlan.
7983 VPBasicBlock *VPBB = new VPBasicBlock("Pre-Entry");
7984 auto Plan = llvm::make_unique<VPlan>(VPBB);
7985
7986 // Represent values that will have defs inside VPlan.
7987 for (Value *V : NeedDef)
7988 Plan->addVPValue(V);
7989
7990 // Scan the body of the loop in a topological order to visit each basic block
7991 // after having visited its predecessor basic blocks.
7992 LoopBlocksDFS DFS(OrigLoop);
7993 DFS.perform(LI);
7994
7995 for (BasicBlock *BB : make_range(DFS.beginRPO(), DFS.endRPO())) {
7996 // Relevant instructions from basic block BB will be grouped into VPRecipe
7997 // ingredients and fill a new VPBasicBlock.
7998 unsigned VPBBsForBB = 0;
7999 auto *FirstVPBBForBB = new VPBasicBlock(BB->getName());
8000 VPBB->setOneSuccessor(FirstVPBBForBB);
8001 VPBB = FirstVPBBForBB;
8002 Builder.setInsertPoint(VPBB);
8003
8004 std::vector<Instruction *> Ingredients;
8005
8006 // Organize the ingredients to vectorize from current basic block in the
8007 // right order.
8008 for (Instruction &I : *BB) {
8009 Instruction *Instr = &I;
8010
8011 // First filter out irrelevant instructions, to ensure no recipes are
8012 // built for them.
8013 if (isa<BranchInst>(Instr) || isa<DbgInfoIntrinsic>(Instr) ||
8014 DeadInstructions.count(Instr))
8015 continue;
8016
8017 // I is a member of an InterleaveGroup for Range.Start. If it's an adjunct
8018 // member of the IG, do not construct any Recipe for it.
8019 const InterleaveGroup *IG = Legal->getInterleavedAccessGroup(Instr);
8020 if (IG && Instr != IG->getInsertPos() &&
8021 Range.Start >= 2 && // Query is illegal for VF == 1
8022 CM.getWideningDecision(Instr, Range.Start) ==
8023 LoopVectorizationCostModel::CM_Interleave) {
8024 if (SinkAfterInverse.count(Instr))
8025 Ingredients.push_back(SinkAfterInverse.find(Instr)->second);
8026 continue;
8027 }
8028
8029 // Move instructions to handle first-order recurrences, step 1: avoid
8030 // handling this instruction until after we've handled the instruction it
8031 // should follow.
8032 auto SAIt = SinkAfter.find(Instr);
8033 if (SAIt != SinkAfter.end()) {
8034 DEBUG(dbgs() << "Sinking" << *SAIt->first << " after" << *SAIt->seconddo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "Sinking" << *SAIt
->first << " after" << *SAIt->second <<
" to vectorize a 1st order recurrence.\n"; } } while (false)
8035 << " to vectorize a 1st order recurrence.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "Sinking" << *SAIt
->first << " after" << *SAIt->second <<
" to vectorize a 1st order recurrence.\n"; } } while (false)
;
8036 SinkAfterInverse[SAIt->second] = Instr;
8037 continue;
8038 }
8039
8040 Ingredients.push_back(Instr);
8041
8042 // Move instructions to handle first-order recurrences, step 2: push the
8043 // instruction to be sunk at its insertion point.
8044 auto SAInvIt = SinkAfterInverse.find(Instr);
8045 if (SAInvIt != SinkAfterInverse.end())
8046 Ingredients.push_back(SAInvIt->second);
8047 }
8048
8049 // Introduce each ingredient into VPlan.
8050 for (Instruction *Instr : Ingredients) {
8051 VPRecipeBase *Recipe = nullptr;
8052
8053 // Check if Instr should belong to an interleave memory recipe, or already
8054 // does. In the latter case Instr is irrelevant.
8055 if ((Recipe = tryToInterleaveMemory(Instr, Range))) {
8056 VPBB->appendRecipe(Recipe);
8057 continue;
8058 }
8059
8060 // Check if Instr is a memory operation that should be widened.
8061 if ((Recipe = tryToWidenMemory(Instr, Range, Plan))) {
8062 VPBB->appendRecipe(Recipe);
8063 continue;
8064 }
8065
8066 // Check if Instr should form some PHI recipe.
8067 if ((Recipe = tryToOptimizeInduction(Instr, Range))) {
8068 VPBB->appendRecipe(Recipe);
8069 continue;
8070 }
8071 if ((Recipe = tryToBlend(Instr, Plan))) {
8072 VPBB->appendRecipe(Recipe);
8073 continue;
8074 }
8075 if (PHINode *Phi = dyn_cast<PHINode>(Instr)) {
8076 VPBB->appendRecipe(new VPWidenPHIRecipe(Phi));
8077 continue;
8078 }
8079
8080 // Check if Instr is to be widened by a general VPWidenRecipe, after
8081 // having first checked for specific widening recipes that deal with
8082 // Interleave Groups, Inductions and Phi nodes.
8083 if (tryToWiden(Instr, VPBB, Range))
8084 continue;
8085
8086 // Otherwise, if all widening options failed, Instruction is to be
8087 // replicated. This may create a successor for VPBB.
8088 VPBasicBlock *NextVPBB =
8089 handleReplication(Instr, Range, VPBB, PredInst2Recipe, Plan);
8090 if (NextVPBB != VPBB) {
8091 VPBB = NextVPBB;
8092 VPBB->setName(BB->hasName() ? BB->getName() + "." + Twine(VPBBsForBB++)
8093 : "");
8094 }
8095 }
8096 }
8097
8098 // Discard empty dummy pre-entry VPBasicBlock. Note that other VPBasicBlocks
8099 // may also be empty, such as the last one VPBB, reflecting original
8100 // basic-blocks with no recipes.
8101 VPBasicBlock *PreEntry = cast<VPBasicBlock>(Plan->getEntry());
8102 assert(PreEntry->empty() && "Expecting empty pre-entry block.")(static_cast <bool> (PreEntry->empty() && "Expecting empty pre-entry block."
) ? void (0) : __assert_fail ("PreEntry->empty() && \"Expecting empty pre-entry block.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8102, __extension__ __PRETTY_FUNCTION__))
;
8103 VPBlockBase *Entry = Plan->setEntry(PreEntry->getSingleSuccessor());
8104 PreEntry->disconnectSuccessor(Entry);
8105 delete PreEntry;
8106
8107 std::string PlanName;
8108 raw_string_ostream RSO(PlanName);
8109 unsigned VF = Range.Start;
8110 Plan->addVF(VF);
8111 RSO << "Initial VPlan for VF={" << VF;
8112 for (VF *= 2; VF < Range.End; VF *= 2) {
8113 Plan->addVF(VF);
8114 RSO << "," << VF;
8115 }
8116 RSO << "},UF>=1";
8117 RSO.flush();
8118 Plan->setName(PlanName);
8119
8120 return Plan;
8121}
8122
8123Value* LoopVectorizationPlanner::VPCallbackILV::
8124getOrCreateVectorValues(Value *V, unsigned Part) {
8125 return ILV.getOrCreateVectorValue(V, Part);
8126}
8127
8128void VPInterleaveRecipe::print(raw_ostream &O, const Twine &Indent) const {
8129 O << " +\n"
8130 << Indent << "\"INTERLEAVE-GROUP with factor " << IG->getFactor() << " at ";
8131 IG->getInsertPos()->printAsOperand(O, false);
8132 O << "\\l\"";
8133 for (unsigned i = 0; i < IG->getFactor(); ++i)
8134 if (Instruction *I = IG->getMember(i))
8135 O << " +\n"
8136 << Indent << "\" " << VPlanIngredient(I) << " " << i << "\\l\"";
8137}
8138
8139void VPWidenRecipe::execute(VPTransformState &State) {
8140 for (auto &Instr : make_range(Begin, End))
8141 State.ILV->widenInstruction(Instr);
8142}
8143
8144void VPWidenIntOrFpInductionRecipe::execute(VPTransformState &State) {
8145 assert(!State.Instance && "Int or FP induction being replicated.")(static_cast <bool> (!State.Instance && "Int or FP induction being replicated."
) ? void (0) : __assert_fail ("!State.Instance && \"Int or FP induction being replicated.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8145, __extension__ __PRETTY_FUNCTION__))
;
8146 State.ILV->widenIntOrFpInduction(IV, Trunc);
8147}
8148
8149void VPWidenPHIRecipe::execute(VPTransformState &State) {
8150 State.ILV->widenPHIInstruction(Phi, State.UF, State.VF);
8151}
8152
8153void VPBlendRecipe::execute(VPTransformState &State) {
8154 State.ILV->setDebugLocFromInst(State.Builder, Phi);
8155 // We know that all PHIs in non-header blocks are converted into
8156 // selects, so we don't have to worry about the insertion order and we
8157 // can just use the builder.
8158 // At this point we generate the predication tree. There may be
8159 // duplications since this is a simple recursive scan, but future
8160 // optimizations will clean it up.
8161
8162 unsigned NumIncoming = Phi->getNumIncomingValues();
8163
8164 assert((User || NumIncoming == 1) &&(static_cast <bool> ((User || NumIncoming == 1) &&
"Multiple predecessors with predecessors having a full mask"
) ? void (0) : __assert_fail ("(User || NumIncoming == 1) && \"Multiple predecessors with predecessors having a full mask\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8165, __extension__ __PRETTY_FUNCTION__))
8165 "Multiple predecessors with predecessors having a full mask")(static_cast <bool> ((User || NumIncoming == 1) &&
"Multiple predecessors with predecessors having a full mask"
) ? void (0) : __assert_fail ("(User || NumIncoming == 1) && \"Multiple predecessors with predecessors having a full mask\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8165, __extension__ __PRETTY_FUNCTION__))
;
8166 // Generate a sequence of selects of the form:
8167 // SELECT(Mask3, In3,
8168 // SELECT(Mask2, In2,
8169 // ( ...)))
8170 InnerLoopVectorizer::VectorParts Entry(State.UF);
8171 for (unsigned In = 0; In < NumIncoming; ++In) {
8172 for (unsigned Part = 0; Part < State.UF; ++Part) {
8173 // We might have single edge PHIs (blocks) - use an identity
8174 // 'select' for the first PHI operand.
8175 Value *In0 =
8176 State.ILV->getOrCreateVectorValue(Phi->getIncomingValue(In), Part);
8177 if (In == 0)
8178 Entry[Part] = In0; // Initialize with the first incoming value.
8179 else {
8180 // Select between the current value and the previous incoming edge
8181 // based on the incoming mask.
8182 Value *Cond = State.get(User->getOperand(In), Part);
8183 Entry[Part] =
8184 State.Builder.CreateSelect(Cond, In0, Entry[Part], "predphi");
8185 }
8186 }
8187 }
8188 for (unsigned Part = 0; Part < State.UF; ++Part)
8189 State.ValueMap.setVectorValue(Phi, Part, Entry[Part]);
8190}
8191
8192void VPInterleaveRecipe::execute(VPTransformState &State) {
8193 assert(!State.Instance && "Interleave group being replicated.")(static_cast <bool> (!State.Instance && "Interleave group being replicated."
) ? void (0) : __assert_fail ("!State.Instance && \"Interleave group being replicated.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8193, __extension__ __PRETTY_FUNCTION__))
;
8194 State.ILV->vectorizeInterleaveGroup(IG->getInsertPos());
8195}
8196
8197void VPReplicateRecipe::execute(VPTransformState &State) {
8198 if (State.Instance) { // Generate a single instance.
8199 State.ILV->scalarizeInstruction(Ingredient, *State.Instance, IsPredicated);
8200 // Insert scalar instance packing it into a vector.
8201 if (AlsoPack && State.VF > 1) {
8202 // If we're constructing lane 0, initialize to start from undef.
8203 if (State.Instance->Lane == 0) {
8204 Value *Undef =
8205 UndefValue::get(VectorType::get(Ingredient->getType(), State.VF));
8206 State.ValueMap.setVectorValue(Ingredient, State.Instance->Part, Undef);
8207 }
8208 State.ILV->packScalarIntoVectorValue(Ingredient, *State.Instance);
8209 }
8210 return;
8211 }
8212
8213 // Generate scalar instances for all VF lanes of all UF parts, unless the
8214 // instruction is uniform inwhich case generate only the first lane for each
8215 // of the UF parts.
8216 unsigned EndLane = IsUniform ? 1 : State.VF;
8217 for (unsigned Part = 0; Part < State.UF; ++Part)
8218 for (unsigned Lane = 0; Lane < EndLane; ++Lane)
8219 State.ILV->scalarizeInstruction(Ingredient, {Part, Lane}, IsPredicated);
8220}
8221
8222void VPBranchOnMaskRecipe::execute(VPTransformState &State) {
8223 assert(State.Instance && "Branch on Mask works only on single instance.")(static_cast <bool> (State.Instance && "Branch on Mask works only on single instance."
) ? void (0) : __assert_fail ("State.Instance && \"Branch on Mask works only on single instance.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8223, __extension__ __PRETTY_FUNCTION__))
;
8224
8225 unsigned Part = State.Instance->Part;
8226 unsigned Lane = State.Instance->Lane;
8227
8228 Value *ConditionBit = nullptr;
8229 if (!User) // Block in mask is all-one.
8230 ConditionBit = State.Builder.getTrue();
8231 else {
8232 VPValue *BlockInMask = User->getOperand(0);
8233 ConditionBit = State.get(BlockInMask, Part);
8234 if (ConditionBit->getType()->isVectorTy())
8235 ConditionBit = State.Builder.CreateExtractElement(
8236 ConditionBit, State.Builder.getInt32(Lane));
8237 }
8238
8239 // Replace the temporary unreachable terminator with a new conditional branch,
8240 // whose two destinations will be set later when they are created.
8241 auto *CurrentTerminator = State.CFG.PrevBB->getTerminator();
8242 assert(isa<UnreachableInst>(CurrentTerminator) &&(static_cast <bool> (isa<UnreachableInst>(CurrentTerminator
) && "Expected to replace unreachable terminator with conditional branch."
) ? void (0) : __assert_fail ("isa<UnreachableInst>(CurrentTerminator) && \"Expected to replace unreachable terminator with conditional branch.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8243, __extension__ __PRETTY_FUNCTION__))
8243 "Expected to replace unreachable terminator with conditional branch.")(static_cast <bool> (isa<UnreachableInst>(CurrentTerminator
) && "Expected to replace unreachable terminator with conditional branch."
) ? void (0) : __assert_fail ("isa<UnreachableInst>(CurrentTerminator) && \"Expected to replace unreachable terminator with conditional branch.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8243, __extension__ __PRETTY_FUNCTION__))
;
8244 auto *CondBr = BranchInst::Create(State.CFG.PrevBB, nullptr, ConditionBit);
8245 CondBr->setSuccessor(0, nullptr);
8246 ReplaceInstWithInst(CurrentTerminator, CondBr);
8247}
8248
8249void VPPredInstPHIRecipe::execute(VPTransformState &State) {
8250 assert(State.Instance && "Predicated instruction PHI works per instance.")(static_cast <bool> (State.Instance && "Predicated instruction PHI works per instance."
) ? void (0) : __assert_fail ("State.Instance && \"Predicated instruction PHI works per instance.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8250, __extension__ __PRETTY_FUNCTION__))
;
8251 Instruction *ScalarPredInst = cast<Instruction>(
8252 State.ValueMap.getScalarValue(PredInst, *State.Instance));
8253 BasicBlock *PredicatedBB = ScalarPredInst->getParent();
8254 BasicBlock *PredicatingBB = PredicatedBB->getSinglePredecessor();
8255 assert(PredicatingBB && "Predicated block has no single predecessor.")(static_cast <bool> (PredicatingBB && "Predicated block has no single predecessor."
) ? void (0) : __assert_fail ("PredicatingBB && \"Predicated block has no single predecessor.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8255, __extension__ __PRETTY_FUNCTION__))
;
8256
8257 // By current pack/unpack logic we need to generate only a single phi node: if
8258 // a vector value for the predicated instruction exists at this point it means
8259 // the instruction has vector users only, and a phi for the vector value is
8260 // needed. In this case the recipe of the predicated instruction is marked to
8261 // also do that packing, thereby "hoisting" the insert-element sequence.
8262 // Otherwise, a phi node for the scalar value is needed.
8263 unsigned Part = State.Instance->Part;
8264 if (State.ValueMap.hasVectorValue(PredInst, Part)) {
8265 Value *VectorValue = State.ValueMap.getVectorValue(PredInst, Part);
8266 InsertElementInst *IEI = cast<InsertElementInst>(VectorValue);
8267 PHINode *VPhi = State.Builder.CreatePHI(IEI->getType(), 2);
8268 VPhi->addIncoming(IEI->getOperand(0), PredicatingBB); // Unmodified vector.
8269 VPhi->addIncoming(IEI, PredicatedBB); // New vector with inserted element.
8270 State.ValueMap.resetVectorValue(PredInst, Part, VPhi); // Update cache.
8271 } else {
8272 Type *PredInstType = PredInst->getType();
8273 PHINode *Phi = State.Builder.CreatePHI(PredInstType, 2);
8274 Phi->addIncoming(UndefValue::get(ScalarPredInst->getType()), PredicatingBB);
8275 Phi->addIncoming(ScalarPredInst, PredicatedBB);
8276 State.ValueMap.resetScalarValue(PredInst, *State.Instance, Phi);
8277 }
8278}
8279
8280void VPWidenMemoryInstructionRecipe::execute(VPTransformState &State) {
8281 if (!User)
8282 return State.ILV->vectorizeMemoryInstruction(&Instr);
8283
8284 // Last (and currently only) operand is a mask.
8285 InnerLoopVectorizer::VectorParts MaskValues(State.UF);
8286 VPValue *Mask = User->getOperand(User->getNumOperands() - 1);
8287 for (unsigned Part = 0; Part < State.UF; ++Part)
8288 MaskValues[Part] = State.get(Mask, Part);
8289 State.ILV->vectorizeMemoryInstruction(&Instr, &MaskValues);
8290}
8291
8292bool LoopVectorizePass::processLoop(Loop *L) {
8293 assert(L->empty() && "Only process inner loops.")(static_cast <bool> (L->empty() && "Only process inner loops."
) ? void (0) : __assert_fail ("L->empty() && \"Only process inner loops.\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8293, __extension__ __PRETTY_FUNCTION__))
;
8294
8295#ifndef NDEBUG
8296 const std::string DebugLocStr = getDebugLocString(L);
8297#endif /* NDEBUG */
8298
8299 DEBUG(dbgs() << "\nLV: Checking a loop in \""do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "\nLV: Checking a loop in \""
<< L->getHeader()->getParent()->getName() <<
"\" from " << DebugLocStr << "\n"; } } while (false
)
8300 << L->getHeader()->getParent()->getName() << "\" from "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "\nLV: Checking a loop in \""
<< L->getHeader()->getParent()->getName() <<
"\" from " << DebugLocStr << "\n"; } } while (false
)
8301 << DebugLocStr << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "\nLV: Checking a loop in \""
<< L->getHeader()->getParent()->getName() <<
"\" from " << DebugLocStr << "\n"; } } while (false
)
;
8302
8303 LoopVectorizeHints Hints(L, DisableUnrolling, *ORE);
8304
8305 DEBUG(dbgs() << "LV: Loop hints:"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8306 << " force="do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8307 << (Hints.getForce() == LoopVectorizeHints::FK_Disableddo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8308 ? "disabled"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8309 : (Hints.getForce() == LoopVectorizeHints::FK_Enableddo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8310 ? "enabled"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8311 : "?"))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8312 << " width=" << Hints.getWidth()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
8313 << " unroll=" << Hints.getInterleave() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints:" <<
" force=" << (Hints.getForce() == LoopVectorizeHints::
FK_Disabled ? "disabled" : (Hints.getForce() == LoopVectorizeHints
::FK_Enabled ? "enabled" : "?")) << " width=" << Hints
.getWidth() << " unroll=" << Hints.getInterleave(
) << "\n"; } } while (false)
;
8314
8315 // Function containing loop
8316 Function *F = L->getHeader()->getParent();
8317
8318 // Looking at the diagnostic output is the only way to determine if a loop
8319 // was vectorized (other than looking at the IR or machine code), so it
8320 // is important to generate an optimization remark for each loop. Most of
8321 // these messages are generated as OptimizationRemarkAnalysis. Remarks
8322 // generated as OptimizationRemark and OptimizationRemarkMissed are
8323 // less verbose reporting vectorized loops and unvectorized loops that may
8324 // benefit from vectorization, respectively.
8325
8326 if (!Hints.allowVectorization(F, L, AlwaysVectorize)) {
8327 DEBUG(dbgs() << "LV: Loop hints prevent vectorization.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Loop hints prevent vectorization.\n"
; } } while (false)
;
8328 return false;
8329 }
8330
8331 PredicatedScalarEvolution PSE(*SE, *L);
8332
8333 // Check if it is legal to vectorize the loop.
8334 LoopVectorizationRequirements Requirements(*ORE);
8335 LoopVectorizationLegality LVL(L, PSE, DT, TLI, AA, F, TTI, GetLAA, LI, ORE,
8336 &Requirements, &Hints, DB, AC);
8337 if (!LVL.canVectorize()) {
8338 DEBUG(dbgs() << "LV: Not vectorizing: Cannot prove legality.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: Cannot prove legality.\n"
; } } while (false)
;
8339 emitMissedWarning(F, L, Hints, ORE);
8340 return false;
8341 }
8342
8343 // Check the function attributes to find out if this function should be
8344 // optimized for size.
8345 bool OptForSize =
8346 Hints.getForce() != LoopVectorizeHints::FK_Enabled && F->optForSize();
8347
8348 // Check the loop for a trip count threshold: vectorize loops with a tiny trip
8349 // count by optimizing for size, to minimize overheads.
8350 // Prefer constant trip counts over profile data, over upper bound estimate.
8351 unsigned ExpectedTC = 0;
8352 bool HasExpectedTC = false;
8353 if (const SCEVConstant *ConstExits =
8354 dyn_cast<SCEVConstant>(SE->getBackedgeTakenCount(L))) {
8355 const APInt &ExitsCount = ConstExits->getAPInt();
8356 // We are interested in small values for ExpectedTC. Skip over those that
8357 // can't fit an unsigned.
8358 if (ExitsCount.ult(std::numeric_limits<unsigned>::max())) {
8359 ExpectedTC = static_cast<unsigned>(ExitsCount.getZExtValue()) + 1;
8360 HasExpectedTC = true;
8361 }
8362 }
8363 // ExpectedTC may be large because it's bound by a variable. Check
8364 // profiling information to validate we should vectorize.
8365 if (!HasExpectedTC && LoopVectorizeWithBlockFrequency) {
8366 auto EstimatedTC = getLoopEstimatedTripCount(L);
8367 if (EstimatedTC) {
8368 ExpectedTC = *EstimatedTC;
8369 HasExpectedTC = true;
8370 }
8371 }
8372 if (!HasExpectedTC) {
8373 ExpectedTC = SE->getSmallConstantMaxTripCount(L);
8374 HasExpectedTC = (ExpectedTC > 0);
8375 }
8376
8377 if (HasExpectedTC && ExpectedTC < TinyTripCountVectorThreshold) {
8378 DEBUG(dbgs() << "LV: Found a loop with a very small trip count. "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a loop with a very small trip count. "
<< "This loop is worth vectorizing only if no scalar "
<< "iteration overheads are incurred."; } } while (false
)
8379 << "This loop is worth vectorizing only if no scalar "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a loop with a very small trip count. "
<< "This loop is worth vectorizing only if no scalar "
<< "iteration overheads are incurred."; } } while (false
)
8380 << "iteration overheads are incurred.")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a loop with a very small trip count. "
<< "This loop is worth vectorizing only if no scalar "
<< "iteration overheads are incurred."; } } while (false
)
;
8381 if (Hints.getForce() == LoopVectorizeHints::FK_Enabled)
8382 DEBUG(dbgs() << " But vectorizing was explicitly forced.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << " But vectorizing was explicitly forced.\n"
; } } while (false)
;
8383 else {
8384 DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "\n"; } } while (false)
;
8385 // Loops with a very small trip count are considered for vectorization
8386 // under OptForSize, thereby making sure the cost of their loop body is
8387 // dominant, free of runtime guards and scalar iteration overheads.
8388 OptForSize = true;
8389 }
8390 }
8391
8392 // Check the function attributes to see if implicit floats are allowed.
8393 // FIXME: This check doesn't seem possibly correct -- what if the loop is
8394 // an integer loop and the vector instructions selected are purely integer
8395 // vector instructions?
8396 if (F->hasFnAttribute(Attribute::NoImplicitFloat)) {
8397 DEBUG(dbgs() << "LV: Can't vectorize when the NoImplicitFloat"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Can't vectorize when the NoImplicitFloat"
"attribute is used.\n"; } } while (false)
8398 "attribute is used.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Can't vectorize when the NoImplicitFloat"
"attribute is used.\n"; } } while (false)
;
8399 ORE->emit(createMissedAnalysis(Hints.vectorizeAnalysisPassName(),
8400 "NoImplicitFloat", L)
8401 << "loop not vectorized due to NoImplicitFloat attribute");
8402 emitMissedWarning(F, L, Hints, ORE);
8403 return false;
8404 }
8405
8406 // Check if the target supports potentially unsafe FP vectorization.
8407 // FIXME: Add a check for the type of safety issue (denormal, signaling)
8408 // for the target we're vectorizing for, to make sure none of the
8409 // additional fp-math flags can help.
8410 if (Hints.isPotentiallyUnsafe() &&
8411 TTI->isFPVectorizationPotentiallyUnsafe()) {
8412 DEBUG(dbgs() << "LV: Potentially unsafe FP op prevents vectorization.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Potentially unsafe FP op prevents vectorization.\n"
; } } while (false)
;
8413 ORE->emit(
8414 createMissedAnalysis(Hints.vectorizeAnalysisPassName(), "UnsafeFP", L)
8415 << "loop not vectorized due to unsafe FP support.");
8416 emitMissedWarning(F, L, Hints, ORE);
8417 return false;
8418 }
8419
8420 // Use the cost model.
8421 LoopVectorizationCostModel CM(L, PSE, LI, &LVL, *TTI, TLI, DB, AC, ORE, F,
8422 &Hints);
8423 CM.collectValuesToIgnore();
8424
8425 // Use the planner for vectorization.
8426 LoopVectorizationPlanner LVP(L, LI, TLI, TTI, &LVL, CM);
8427
8428 // Get user vectorization factor.
8429 unsigned UserVF = Hints.getWidth();
8430
8431 // Plan how to best vectorize, return the best VF and its cost.
8432 VectorizationFactor VF = LVP.plan(OptForSize, UserVF);
8433
8434 // Select the interleave count.
8435 unsigned IC = CM.selectInterleaveCount(OptForSize, VF.Width, VF.Cost);
8436
8437 // Get user interleave count.
8438 unsigned UserIC = Hints.getInterleave();
8439
8440 // Identify the diagnostic messages that should be produced.
8441 std::pair<StringRef, std::string> VecDiagMsg, IntDiagMsg;
8442 bool VectorizeLoop = true, InterleaveLoop = true;
8443 if (Requirements.doesNotMeet(F, L, Hints)) {
8444 DEBUG(dbgs() << "LV: Not vectorizing: loop did not meet vectorization "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: loop did not meet vectorization "
"requirements.\n"; } } while (false)
8445 "requirements.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Not vectorizing: loop did not meet vectorization "
"requirements.\n"; } } while (false)
;
8446 emitMissedWarning(F, L, Hints, ORE);
8447 return false;
8448 }
8449
8450 if (VF.Width == 1) {
8451 DEBUG(dbgs() << "LV: Vectorization is possible but not beneficial.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Vectorization is possible but not beneficial.\n"
; } } while (false)
;
8452 VecDiagMsg = std::make_pair(
8453 "VectorizationNotBeneficial",
8454 "the cost-model indicates that vectorization is not beneficial");
8455 VectorizeLoop = false;
8456 }
8457
8458 if (IC == 1 && UserIC <= 1) {
8459 // Tell the user interleaving is not beneficial.
8460 DEBUG(dbgs() << "LV: Interleaving is not beneficial.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving is not beneficial.\n"
; } } while (false)
;
8461 IntDiagMsg = std::make_pair(
8462 "InterleavingNotBeneficial",
8463 "the cost-model indicates that interleaving is not beneficial");
8464 InterleaveLoop = false;
8465 if (UserIC == 1) {
8466 IntDiagMsg.first = "InterleavingNotBeneficialAndDisabled";
8467 IntDiagMsg.second +=
8468 " and is explicitly disabled or interleave count is set to 1";
8469 }
8470 } else if (IC > 1 && UserIC == 1) {
8471 // Tell the user interleaving is beneficial, but it explicitly disabled.
8472 DEBUG(dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving is beneficial but is explicitly disabled."
; } } while (false)
8473 << "LV: Interleaving is beneficial but is explicitly disabled.")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleaving is beneficial but is explicitly disabled."
; } } while (false)
;
8474 IntDiagMsg = std::make_pair(
8475 "InterleavingBeneficialButDisabled",
8476 "the cost-model indicates that interleaving is beneficial "
8477 "but is explicitly disabled or interleave count is set to 1");
8478 InterleaveLoop = false;
8479 }
8480
8481 // Override IC if user provided an interleave count.
8482 IC = UserIC > 0 ? UserIC : IC;
8483
8484 // Emit diagnostic messages, if any.
8485 const char *VAPassName = Hints.vectorizeAnalysisPassName();
8486 if (!VectorizeLoop && !InterleaveLoop) {
8487 // Do not vectorize or interleaving the loop.
8488 ORE->emit([&]() {
8489 return OptimizationRemarkMissed(VAPassName, VecDiagMsg.first,
8490 L->getStartLoc(), L->getHeader())
8491 << VecDiagMsg.second;
8492 });
8493 ORE->emit([&]() {
8494 return OptimizationRemarkMissed(LV_NAME"loop-vectorize", IntDiagMsg.first,
8495 L->getStartLoc(), L->getHeader())
8496 << IntDiagMsg.second;
8497 });
8498 return false;
8499 } else if (!VectorizeLoop && InterleaveLoop) {
8500 DEBUG(dbgs() << "LV: Interleave Count is " << IC << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleave Count is "
<< IC << '\n'; } } while (false)
;
8501 ORE->emit([&]() {
8502 return OptimizationRemarkAnalysis(VAPassName, VecDiagMsg.first,
8503 L->getStartLoc(), L->getHeader())
8504 << VecDiagMsg.second;
8505 });
8506 } else if (VectorizeLoop && !InterleaveLoop) {
8507 DEBUG(dbgs() << "LV: Found a vectorizable loop (" << VF.Width << ") in "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a vectorizable loop ("
<< VF.Width << ") in " << DebugLocStr <<
'\n'; } } while (false)
8508 << DebugLocStr << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a vectorizable loop ("
<< VF.Width << ") in " << DebugLocStr <<
'\n'; } } while (false)
;
8509 ORE->emit([&]() {
8510 return OptimizationRemarkAnalysis(LV_NAME"loop-vectorize", IntDiagMsg.first,
8511 L->getStartLoc(), L->getHeader())
8512 << IntDiagMsg.second;
8513 });
8514 } else if (VectorizeLoop && InterleaveLoop) {
8515 DEBUG(dbgs() << "LV: Found a vectorizable loop (" << VF.Width << ") in "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a vectorizable loop ("
<< VF.Width << ") in " << DebugLocStr <<
'\n'; } } while (false)
8516 << DebugLocStr << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Found a vectorizable loop ("
<< VF.Width << ") in " << DebugLocStr <<
'\n'; } } while (false)
;
8517 DEBUG(dbgs() << "LV: Interleave Count is " << IC << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { dbgs() << "LV: Interleave Count is "
<< IC << '\n'; } } while (false)
;
8518 }
8519
8520 LVP.setBestPlan(VF.Width, IC);
8521
8522 using namespace ore;
8523
8524 if (!VectorizeLoop) {
8525 assert(IC > 1 && "interleave count should not be 1 or 0")(static_cast <bool> (IC > 1 && "interleave count should not be 1 or 0"
) ? void (0) : __assert_fail ("IC > 1 && \"interleave count should not be 1 or 0\""
, "/build/llvm-toolchain-snapshot-7~svn324650/lib/Transforms/Vectorize/LoopVectorize.cpp"
, 8525, __extension__ __PRETTY_FUNCTION__))
;
8526 // If we decided that it is not legal to vectorize the loop, then
8527 // interleave it.
8528 InnerLoopUnroller Unroller(L, PSE, LI, DT, TLI, TTI, AC, ORE, IC, &LVL,
8529 &CM);
8530 LVP.executePlan(Unroller, DT);
8531
8532 ORE->emit([&]() {
8533 return OptimizationRemark(LV_NAME"loop-vectorize", "Interleaved", L->getStartLoc(),
8534 L->getHeader())
8535 << "interleaved loop (interleaved count: "
8536 << NV("InterleaveCount", IC) << ")";
8537 });
8538 } else {
8539 // If we decided that it is *legal* to vectorize the loop, then do it.
8540 InnerLoopVectorizer LB(L, PSE, LI, DT, TLI, TTI, AC, ORE, VF.Width, IC,
8541 &LVL, &CM);
8542 LVP.executePlan(LB, DT);
8543 ++LoopsVectorized;
8544
8545 // Add metadata to disable runtime unrolling a scalar loop when there are
8546 // no runtime checks about strides and memory. A scalar loop that is
8547 // rarely used is not worth unrolling.
8548 if (!LB.areSafetyChecksAdded())
8549 AddRuntimeUnrollDisableMetaData(L);
8550
8551 // Report the vectorization decision.
8552 ORE->emit([&]() {
8553 return OptimizationRemark(LV_NAME"loop-vectorize", "Vectorized", L->getStartLoc(),
8554 L->getHeader())
8555 << "vectorized loop (vectorization width: "
8556 << NV("VectorizationFactor", VF.Width)
8557 << ", interleaved count: " << NV("InterleaveCount", IC) << ")";
8558 });
8559 }
8560
8561 // Mark the loop as already vectorized to avoid vectorizing again.
8562 Hints.setAlreadyVectorized();
8563
8564 DEBUG(verifyFunction(*L->getHeader()->getParent()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("loop-vectorize")) { verifyFunction(*L->getHeader()->getParent
()); } } while (false)
;
8565 return true;
8566}
8567
8568bool LoopVectorizePass::runImpl(
8569 Function &F, ScalarEvolution &SE_, LoopInfo &LI_, TargetTransformInfo &TTI_,
8570 DominatorTree &DT_, BlockFrequencyInfo &BFI_, TargetLibraryInfo *TLI_,
8571 DemandedBits &DB_, AliasAnalysis &AA_, AssumptionCache &AC_,
8572 std::function<const LoopAccessInfo &(Loop &)> &GetLAA_,
8573 OptimizationRemarkEmitter &ORE_) {
8574 SE = &SE_;
8575 LI = &LI_;
8576 TTI = &TTI_;
8577 DT = &DT_;
8578 BFI = &BFI_;
8579 TLI = TLI_;
8580 AA = &AA_;
8581 AC = &AC_;
8582 GetLAA = &GetLAA_;
8583 DB = &DB_;
8584 ORE = &ORE_;
8585
8586 // Don't attempt if
8587 // 1. the target claims to have no vector registers, and
8588 // 2. interleaving won't help ILP.
8589 //
8590 // The second condition is necessary because, even if the target has no
8591 // vector registers, loop vectorization may still enable scalar
8592 // interleaving.
8593 if (!TTI->getNumberOfRegisters(true) && TTI->getMaxInterleaveFactor(1) < 2)
8594 return false;
8595
8596 bool Changed = false;
8597
8598 // The vectorizer requires loops to be in simplified form.
8599 // Since simplification may add new inner loops, it has to run before the
8600 // legality and profitability checks. This means running the loop vectorizer
8601 // will simplify all loops, regardless of whether anything end up being
8602 // vectorized.
8603 for (auto &L : *LI)
8604 Changed |= simplifyLoop(L, DT, LI, SE, AC, false /* PreserveLCSSA */);
8605
8606 // Build up a worklist of inner-loops to vectorize. This is necessary as
8607 // the act of vectorizing or partially unrolling a loop creates new loops
8608 // and can invalidate iterators across the loops.
8609 SmallVector<Loop *, 8> Worklist;
8610
8611 for (Loop *L : *LI)
8612 addAcyclicInnerLoop(*L, Worklist);
8613
8614 LoopsAnalyzed += Worklist.size();
8615
8616 // Now walk the identified inner loops.
8617 while (!Worklist.empty()) {
8618 Loop *L = Worklist.pop_back_val();
8619
8620 // For the inner loops we actually process, form LCSSA to simplify the
8621 // transform.
8622 Changed |= formLCSSARecursively(*L, *DT, LI, SE);
8623
8624 Changed |= processLoop(L);
8625 }
8626
8627 // Process each loop nest in the function.
8628 return Changed;
8629}
8630
8631PreservedAnalyses LoopVectorizePass::run(Function &F,
8632 FunctionAnalysisManager &AM) {
8633 auto &SE = AM.getResult<ScalarEvolutionAnalysis>(F);
8634 auto &LI = AM.getResult<LoopAnalysis>(F);
8635 auto &TTI = AM.getResult<TargetIRAnalysis>(F);
8636 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
8637 auto &BFI = AM.getResult<BlockFrequencyAnalysis>(F);
8638 auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
8639 auto &AA = AM.getResult<AAManager>(F);
8640 auto &AC = AM.getResult<AssumptionAnalysis>(F);
8641 auto &DB = AM.getResult<DemandedBitsAnalysis>(F);
8642 auto &ORE = AM.getResult<OptimizationRemarkEmitterAnalysis>(F);
8643
8644 auto &LAM = AM.getResult<LoopAnalysisManagerFunctionProxy>(F).getManager();
8645 std::function<const LoopAccessInfo &(Loop &)> GetLAA =
8646 [&](Loop &L) -> const LoopAccessInfo & {
8647 LoopStandardAnalysisResults AR = {AA, AC, DT, LI, SE, TLI, TTI, nullptr};
8648 return LAM.getResult<LoopAccessAnalysis>(L, AR);
8649 };
8650 bool Changed =
8651 runImpl(F, SE, LI, TTI, DT, BFI, &TLI, DB, AA, AC, GetLAA, ORE);
8652 if (!Changed)
8653 return PreservedAnalyses::all();
8654 PreservedAnalyses PA;
8655 PA.preserve<LoopAnalysis>();
8656 PA.preserve<DominatorTreeAnalysis>();
8657 PA.preserve<BasicAA>();
8658 PA.preserve<GlobalsAA>();
8659 return PA;
8660}