LLVM 19.0.0git
LoopVectorize.h
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1//===- LoopVectorize.h ------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This is the LLVM loop vectorizer. This pass modifies 'vectorizable' loops
10// and generates target-independent LLVM-IR.
11// The vectorizer uses the TargetTransformInfo analysis to estimate the costs
12// of instructions in order to estimate the profitability of vectorization.
13//
14// The loop vectorizer combines consecutive loop iterations into a single
15// 'wide' iteration. After this transformation the index is incremented
16// by the SIMD vector width, and not by one.
17//
18// This pass has four parts:
19// 1. The main loop pass that drives the different parts.
20// 2. LoopVectorizationLegality - A unit that checks for the legality
21// of the vectorization.
22// 3. InnerLoopVectorizer - A unit that performs the actual
23// widening of instructions.
24// 4. LoopVectorizationCostModel - A unit that checks for the profitability
25// of vectorization. It decides on the optimal vector width, which
26// can be one, if vectorization is not profitable.
27//
28// There is a development effort going on to migrate loop vectorizer to the
29// VPlan infrastructure and to introduce outer loop vectorization support (see
30// docs/VectorizationPlan.rst and
31// http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html). For this
32// purpose, we temporarily introduced the VPlan-native vectorization path: an
33// alternative vectorization path that is natively implemented on top of the
34// VPlan infrastructure. See EnableVPlanNativePath for enabling.
35//
36//===----------------------------------------------------------------------===//
37//
38// The reduction-variable vectorization is based on the paper:
39// D. Nuzman and R. Henderson. Multi-platform Auto-vectorization.
40//
41// Variable uniformity checks are inspired by:
42// Karrenberg, R. and Hack, S. Whole Function Vectorization.
43//
44// The interleaved access vectorization is based on the paper:
45// Dorit Nuzman, Ira Rosen and Ayal Zaks. Auto-Vectorization of Interleaved
46// Data for SIMD
47//
48// Other ideas/concepts are from:
49// A. Zaks and D. Nuzman. Autovectorization in GCC-two years later.
50//
51// S. Maleki, Y. Gao, M. Garzaran, T. Wong and D. Padua. An Evaluation of
52// Vectorizing Compilers.
53//
54//===----------------------------------------------------------------------===//
55
56#ifndef LLVM_TRANSFORMS_VECTORIZE_LOOPVECTORIZE_H
57#define LLVM_TRANSFORMS_VECTORIZE_LOOPVECTORIZE_H
58
59#include "llvm/IR/PassManager.h"
61#include <functional>
62
63namespace llvm {
64
65class AssumptionCache;
66class BlockFrequencyInfo;
67class DemandedBits;
68class DominatorTree;
69class Function;
70class Loop;
71class LoopAccessInfoManager;
72class LoopInfo;
73class OptimizationRemarkEmitter;
74class ProfileSummaryInfo;
75class ScalarEvolution;
76class TargetLibraryInfo;
77class TargetTransformInfo;
78
79extern cl::opt<bool> EnableLoopInterleaving;
80extern cl::opt<bool> EnableLoopVectorization;
81
82/// A marker to determine if extra passes after loop vectorization should be
83/// run.
85 : public AnalysisInfoMixin<ShouldRunExtraVectorPasses> {
87 struct Result {
90 // Check whether the analysis has been explicitly invalidated. Otherwise,
91 // it remains preserved.
93 return !PAC.preservedWhenStateless();
94 }
95 };
96
98};
99
100/// A pass manager to run a set of extra function simplification passes after
101/// vectorization, if requested. LoopVectorize caches the
102/// ShouldRunExtraVectorPasses analysis to request extra simplifications, if
103/// they could be beneficial.
106 auto PA = PreservedAnalyses::all();
108 PA.intersect(FunctionPassManager::run(F, AM));
109 PA.abandon<ShouldRunExtraVectorPasses>();
110 return PA;
111 }
112};
113
115 /// If false, consider all loops for interleaving.
116 /// If true, only loops that explicitly request interleaving are considered.
118
119 /// If false, consider all loops for vectorization.
120 /// If true, only loops that explicitly request vectorization are considered.
122
123 /// The current defaults when creating the pass with no arguments are:
124 /// EnableLoopInterleaving = true and EnableLoopVectorization = true. This
125 /// means that interleaving default is consistent with the cl::opt flag, while
126 /// vectorization is not.
127 /// FIXME: The default for EnableLoopVectorization in the cl::opt should be
128 /// set to true, and the corresponding change to account for this be made in
129 /// opt.cpp. The initializations below will become:
130 /// InterleaveOnlyWhenForced(!EnableLoopInterleaving)
131 /// VectorizeOnlyWhenForced(!EnableLoopVectorization).
138
141 return *this;
142 }
143
146 return *this;
147 }
148};
149
150/// Storage for information about made changes.
154
157};
158
159/// The LoopVectorize Pass.
160struct LoopVectorizePass : public PassInfoMixin<LoopVectorizePass> {
161private:
162 /// If false, consider all loops for interleaving.
163 /// If true, only loops that explicitly request interleaving are considered.
164 bool InterleaveOnlyWhenForced;
165
166 /// If false, consider all loops for vectorization.
167 /// If true, only loops that explicitly request vectorization are considered.
168 bool VectorizeOnlyWhenForced;
169
170public:
172
184
187 function_ref<StringRef(StringRef)> MapClassName2PassName);
188
189 // Shim for old PM.
193 DemandedBits &DB_, AssumptionCache &AC_,
196 ProfileSummaryInfo *PSI_);
197
198 bool processLoop(Loop *L);
199};
200
201/// Reports a vectorization failure: print \p DebugMsg for debugging
202/// purposes along with the corresponding optimization remark \p RemarkName.
203/// If \p I is passed, it is an instruction that prevents vectorization.
204/// Otherwise, the loop \p TheLoop is used for the location of the remark.
205void reportVectorizationFailure(const StringRef DebugMsg,
206 const StringRef OREMsg, const StringRef ORETag,
207 OptimizationRemarkEmitter *ORE, Loop *TheLoop, Instruction *I = nullptr);
208
209/// Reports an informative message: print \p Msg for debugging purposes as well
210/// as an optimization remark. Uses either \p I as location of the remark, or
211/// otherwise \p TheLoop.
212void reportVectorizationInfo(const StringRef OREMsg, const StringRef ORETag,
213 OptimizationRemarkEmitter *ORE, Loop *TheLoop,
214 Instruction *I = nullptr);
215
216} // end namespace llvm
217
218#endif // LLVM_TRANSFORMS_VECTORIZE_LOOPVECTORIZE_H
#define F(x, y, z)
Definition: MD5.cpp:55
#define I(x, y, z)
Definition: MD5.cpp:58
FunctionAnalysisManager FAM
This header defines various interfaces for pass management in LLVM.
raw_pwrite_stream & OS
API to communicate dependencies between analyses during invalidation.
Definition: PassManager.h:387
A container for analyses that lazily runs them and caches their results.
Definition: PassManager.h:348
PassT::Result * getCachedResult(IRUnitT &IR) const
Get the cached result of an analysis pass for a given IR unit.
Definition: PassManager.h:519
A cache of @llvm.assume calls within a function.
BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to estimate IR basic block frequen...
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree.
Definition: Dominators.h:162
Represents a single loop in the control flow graph.
Definition: LoopInfo.h:44
The optimization diagnostic interface.
PreservedAnalyses run(Function &IR, AnalysisManager< Function > &AM, ExtraArgTs... ExtraArgs)
Run all of the passes in this manager over the given unit of IR.
Definition: PassManager.h:218
A set of analyses that are preserved following a run of a transformation pass.
Definition: Analysis.h:109
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
Definition: Analysis.h:115
PreservedAnalysisChecker getChecker() const
Build a checker for this PreservedAnalyses and the specified analysis type.
Definition: Analysis.h:264
Analysis providing profile information.
The main scalar evolution driver.
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
Provides information about what library functions are available for the current target.
This pass provides access to the codegen interfaces that are needed for IR-level transformations.
LLVM Value Representation.
Definition: Value.h:74
An efficient, type-erasing, non-owning reference to a callable.
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
cl::opt< bool > EnableLoopVectorization
void reportVectorizationFailure(const StringRef DebugMsg, const StringRef OREMsg, const StringRef ORETag, OptimizationRemarkEmitter *ORE, Loop *TheLoop, Instruction *I=nullptr)
Reports a vectorization failure: print DebugMsg for debugging purposes along with the corresponding o...
void reportVectorizationInfo(const StringRef OREMsg, const StringRef ORETag, OptimizationRemarkEmitter *ORE, Loop *TheLoop, Instruction *I=nullptr)
Reports an informative message: print Msg for debugging purposes as well as an optimization remark.
cl::opt< bool > EnableLoopInterleaving
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:114
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: Analysis.h:26
A pass manager to run a set of extra function simplification passes after vectorization,...
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM)
LoopVectorizeOptions(bool InterleaveOnlyWhenForced, bool VectorizeOnlyWhenForced)
LoopVectorizeOptions & setVectorizeOnlyWhenForced(bool Value)
LoopVectorizeOptions & setInterleaveOnlyWhenForced(bool Value)
LoopVectorizeOptions()
The current defaults when creating the pass with no arguments are: EnableLoopInterleaving = true and ...
bool InterleaveOnlyWhenForced
If false, consider all loops for interleaving.
bool VectorizeOnlyWhenForced
If false, consider all loops for vectorization.
The LoopVectorize Pass.
TargetLibraryInfo * TLI
ProfileSummaryInfo * PSI
LoopAccessInfoManager * LAIs
void printPipeline(raw_ostream &OS, function_ref< StringRef(StringRef)> MapClassName2PassName)
BlockFrequencyInfo * BFI
ScalarEvolution * SE
AssumptionCache * AC
LoopVectorizeResult runImpl(Function &F, ScalarEvolution &SE_, LoopInfo &LI_, TargetTransformInfo &TTI_, DominatorTree &DT_, BlockFrequencyInfo *BFI_, TargetLibraryInfo *TLI_, DemandedBits &DB_, AssumptionCache &AC_, LoopAccessInfoManager &LAIs_, OptimizationRemarkEmitter &ORE_, ProfileSummaryInfo *PSI_)
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM)
OptimizationRemarkEmitter * ORE
TargetTransformInfo * TTI
Storage for information about made changes.
LoopVectorizeResult(bool MadeAnyChange, bool MadeCFGChange)
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:91
bool invalidate(Function &F, const PreservedAnalyses &PA, FunctionAnalysisManager::Invalidator &)
Definition: LoopVectorize.h:88
A marker to determine if extra passes after loop vectorization should be run.
Definition: LoopVectorize.h:85
Result run(Function &F, FunctionAnalysisManager &FAM)
Definition: LoopVectorize.h:97