1//===---- CGLoopInfo.h - LLVM CodeGen for loop metadata -*- 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 internal state used for llvm translation for loop statement
10// metadata.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
15#define LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/IR/DebugLoc.h"
20#include "llvm/IR/Value.h"
21#include "llvm/Support/Compiler.h"
22
23namespace llvm {
24class BasicBlock;
25class Instruction;
26class MDNode;
27} // end namespace llvm
28
29namespace clang {
30class Attr;
31class ASTContext;
32class CodeGenOptions;
33namespace CodeGen {
34
35/// Attributes that may be specified on loops.
36struct LoopAttributes {
37 explicit LoopAttributes(bool IsParallel = false);
38 void clear();
39
40 /// Generate llvm.loop.parallel metadata for loads and stores.
41 bool IsParallel;
42
43 /// State of loop vectorization or unrolling.
44 enum LVEnableState { Unspecified, Enable, Disable, Full };
45
46 /// Value for llvm.loop.vectorize.enable metadata.
47 LVEnableState VectorizeEnable;
48
49 /// Value for llvm.loop.unroll.* metadata (enable, disable, or full).
50 LVEnableState UnrollEnable;
51
52 /// Value for llvm.loop.unroll_and_jam.* metadata (enable, disable, or full).
53 LVEnableState UnrollAndJamEnable;
54
55 /// Value for llvm.loop.vectorize.predicate metadata
56 LVEnableState VectorizePredicateEnable;
57
58 /// Value for llvm.loop.vectorize.width metadata.
59 unsigned VectorizeWidth;
60
61 // Value for llvm.loop.vectorize.scalable.enable
62 LVEnableState VectorizeScalable;
63
64 /// Value for llvm.loop.interleave.count metadata.
65 unsigned InterleaveCount;
66
67 /// llvm.unroll.
68 unsigned UnrollCount;
69
70 /// llvm.unroll.
71 unsigned UnrollAndJamCount;
72
73 /// Value for llvm.loop.distribute.enable metadata.
74 LVEnableState DistributeEnable;
75
76 /// Value for llvm.loop.pipeline.disable metadata.
77 bool PipelineDisabled;
78
79 /// Value for llvm.loop.pipeline.iicount metadata.
80 unsigned PipelineInitiationInterval;
81
82 /// Value for 'llvm.loop.align' metadata.
83 unsigned CodeAlign;
84
85 /// Value for whether the loop is required to make progress.
86 bool MustProgress;
87};
88
89/// Information used when generating a structured loop.
90class LoopInfo {
91public:
92 /// Construct a new LoopInfo for the loop with entry Header.
93 LoopInfo(llvm::BasicBlock *Header, const LoopAttributes &Attrs,
94 const llvm::DebugLoc &StartLoc, const llvm::DebugLoc &EndLoc,
95 LoopInfo *Parent);
96
97 /// Get the loop id metadata for this loop.
98 llvm::MDNode *getLoopID() const { return TempLoopID.get(); }
99
100 /// Get the header block of this loop.
101 llvm::BasicBlock *getHeader() const { return Header; }
102
103 /// Get the set of attributes active for this loop.
104 const LoopAttributes &getAttributes() const { return Attrs; }
105
106 /// Return this loop's access group or nullptr if it does not have one.
107 llvm::MDNode *getAccessGroup() const { return AccGroup; }
108
109 /// Create the loop's metadata. Must be called after its nested loops have
110 /// been processed.
111 void finish();
112
113private:
114 /// Loop ID metadata.
115 llvm::TempMDTuple TempLoopID;
116 /// Header block of this loop.
117 llvm::BasicBlock *Header;
118 /// The attributes for this loop.
119 LoopAttributes Attrs;
120 /// The access group for memory accesses parallel to this loop.
121 llvm::MDNode *AccGroup = nullptr;
122 /// Start location of this loop.
123 llvm::DebugLoc StartLoc;
124 /// End location of this loop.
125 llvm::DebugLoc EndLoc;
126 /// The next outer loop, or nullptr if this is the outermost loop.
127 LoopInfo *Parent;
128 /// If this loop has unroll-and-jam metadata, this can be set by the inner
129 /// loop's LoopInfo to set the llvm.loop.unroll_and_jam.followup_inner
130 /// metadata.
131 llvm::MDNode *UnrollAndJamInnerFollowup = nullptr;
132
133 /// Create a LoopID without any transformations.
134 llvm::MDNode *
135 createLoopPropertiesMetadata(llvm::ArrayRef<llvm::Metadata *> LoopProperties);
136
137 /// Create a LoopID for transformations.
138 ///
139 /// The methods call each other in case multiple transformations are applied
140 /// to a loop. The transformation first to be applied will use LoopID of the
141 /// next transformation in its followup attribute.
142 ///
143 /// @param Attrs The loop's transformations.
144 /// @param LoopProperties Non-transformation properties such as debug
145 /// location, parallel accesses and disabled
146 /// transformations. These are added to the returned
147 /// LoopID.
148 /// @param HasUserTransforms [out] Set to true if the returned MDNode encodes
149 /// at least one transformation.
150 ///
151 /// @return A LoopID (metadata node) that can be used for the llvm.loop
152 /// annotation or followup-attribute.
153 /// @{
154 llvm::MDNode *
155 createPipeliningMetadata(const LoopAttributes &Attrs,
156 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
157 bool &HasUserTransforms);
158 llvm::MDNode *
159 createPartialUnrollMetadata(const LoopAttributes &Attrs,
160 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
161 bool &HasUserTransforms);
162 llvm::MDNode *
163 createUnrollAndJamMetadata(const LoopAttributes &Attrs,
164 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
165 bool &HasUserTransforms);
166 llvm::MDNode *
167 createLoopVectorizeMetadata(const LoopAttributes &Attrs,
168 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
169 bool &HasUserTransforms);
170 llvm::MDNode *
171 createLoopDistributeMetadata(const LoopAttributes &Attrs,
172 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
173 bool &HasUserTransforms);
174 llvm::MDNode *
175 createFullUnrollMetadata(const LoopAttributes &Attrs,
176 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
177 bool &HasUserTransforms);
178 /// @}
179
180 /// Create a LoopID for this loop, including transformation-unspecific
181 /// metadata such as debug location.
182 ///
183 /// @param Attrs This loop's attributes and transformations.
184 /// @param LoopProperties Additional non-transformation properties to add
185 /// to the LoopID, such as transformation-specific
186 /// metadata that are not covered by @p Attrs.
187 /// @param HasUserTransforms [out] Set to true if the returned MDNode encodes
188 /// at least one transformation.
189 ///
190 /// @return A LoopID (metadata node) that can be used for the llvm.loop
191 /// annotation.
192 llvm::MDNode *createMetadata(const LoopAttributes &Attrs,
193 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
194 bool &HasUserTransforms);
195};
196
197/// A stack of loop information corresponding to loop nesting levels.
198/// This stack can be used to prepare attributes which are applied when a loop
199/// is emitted.
200class LoopInfoStack {
201 LoopInfoStack(const LoopInfoStack &) = delete;
202 void operator=(const LoopInfoStack &) = delete;
203
204public:
205 LoopInfoStack() {}
206
207 /// Begin a new structured loop. The set of staged attributes will be
208 /// applied to the loop and then cleared.
209 void push(llvm::BasicBlock *Header, const llvm::DebugLoc &StartLoc,
210 const llvm::DebugLoc &EndLoc);
211
212 /// Begin a new structured loop. Stage attributes from the Attrs list.
213 /// The staged attributes are applied to the loop and then cleared.
214 void push(llvm::BasicBlock *Header, clang::ASTContext &Ctx,
215 const clang::CodeGenOptions &CGOpts,
216 llvm::ArrayRef<const Attr *> Attrs, const llvm::DebugLoc &StartLoc,
217 const llvm::DebugLoc &EndLoc, bool MustProgress = false);
218
219 /// End the current loop.
220 void pop();
221
222 /// Return the top loop id metadata.
223 llvm::MDNode *getCurLoopID() const { return getInfo().getLoopID(); }
224
225 /// Return true if the top loop is parallel.
226 bool getCurLoopParallel() const {
227 return hasInfo() ? getInfo().getAttributes().IsParallel : false;
228 }
229
230 /// Function called by the CodeGenFunction when an instruction is
231 /// created.
232 void InsertHelper(llvm::Instruction *I) const;
233
234 /// Set the next pushed loop as parallel.
235 void setParallel(bool Enable = true) { StagedAttrs.IsParallel = Enable; }
236
237 /// Set the next pushed loop 'vectorize.enable'
238 void setVectorizeEnable(bool Enable = true) {
239 StagedAttrs.VectorizeEnable =
240 Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
241 }
242
243 /// Set the next pushed loop as a distribution candidate.
244 void setDistributeState(bool Enable = true) {
245 StagedAttrs.DistributeEnable =
246 Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
247 }
248
249 /// Set the next pushed loop unroll state.
250 void setUnrollState(const LoopAttributes::LVEnableState &State) {
251 StagedAttrs.UnrollEnable = State;
252 }
253
254 /// Set the next pushed vectorize predicate state.
255 void setVectorizePredicateState(const LoopAttributes::LVEnableState &State) {
256 StagedAttrs.VectorizePredicateEnable = State;
257 }
258
259 /// Set the next pushed loop unroll_and_jam state.
260 void setUnrollAndJamState(const LoopAttributes::LVEnableState &State) {
261 StagedAttrs.UnrollAndJamEnable = State;
262 }
263
264 /// Set the vectorize width for the next loop pushed.
265 void setVectorizeWidth(unsigned W) { StagedAttrs.VectorizeWidth = W; }
266
267 void setVectorizeScalable(const LoopAttributes::LVEnableState &State) {
268 StagedAttrs.VectorizeScalable = State;
269 }
270
271 /// Set the interleave count for the next loop pushed.
272 void setInterleaveCount(unsigned C) { StagedAttrs.InterleaveCount = C; }
273
274 /// Set the unroll count for the next loop pushed.
275 void setUnrollCount(unsigned C) { StagedAttrs.UnrollCount = C; }
276
277 /// \brief Set the unroll count for the next loop pushed.
278 void setUnrollAndJamCount(unsigned C) { StagedAttrs.UnrollAndJamCount = C; }
279
280 /// Set the pipeline disabled state.
281 void setPipelineDisabled(bool S) { StagedAttrs.PipelineDisabled = S; }
282
283 /// Set the pipeline initiation interval.
284 void setPipelineInitiationInterval(unsigned C) {
285 StagedAttrs.PipelineInitiationInterval = C;
286 }
287
288 /// Set value of code align for the next loop pushed.
289 void setCodeAlign(unsigned C) { StagedAttrs.CodeAlign = C; }
290
291 /// Set no progress for the next loop pushed.
292 void setMustProgress(bool P) { StagedAttrs.MustProgress = P; }
293
294private:
295 /// Returns true if there is LoopInfo on the stack.
296 bool hasInfo() const { return !Active.empty(); }
297 /// Return the LoopInfo for the current loop. HasInfo should be called
298 /// first to ensure LoopInfo is present.
299 const LoopInfo &getInfo() const { return *Active.back(); }
300 /// The set of attributes that will be applied to the next pushed loop.
301 LoopAttributes StagedAttrs;
302 /// Stack of active loops.
303 llvm::SmallVector<std::unique_ptr<LoopInfo>, 4> Active;
304};
305
306} // end namespace CodeGen
307} // end namespace clang
308
309#endif
310

source code of clang/lib/CodeGen/CGLoopInfo.h