Bug Summary

File:llvm/lib/CodeGen/CodeGenPrepare.cpp
Warning:line 1013, column 37
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name CodeGenPrepare.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -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 -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -mframe-pointer=none -fmath-errno -fno-rounding-math -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -dwarf-column-info -fno-split-dwarf-inlining -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-11/lib/clang/11.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/build-llvm/include -I /build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-11/lib/clang/11.0.0/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++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/build-llvm/lib/CodeGen -fdebug-prefix-map=/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2020-03-09-184146-41876-1 -x c++ /build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp
1//===- CodeGenPrepare.cpp - Prepare a function for code generation --------===//
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 pass munges the code in the input function to better prepare it for
10// SelectionDAG-based code generation. This works around limitations in it's
11// basic-block-at-a-time approach. It should eventually be removed.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/ADT/APInt.h"
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/MapVector.h"
19#include "llvm/ADT/PointerIntPair.h"
20#include "llvm/ADT/STLExtras.h"
21#include "llvm/ADT/SmallPtrSet.h"
22#include "llvm/ADT/SmallVector.h"
23#include "llvm/ADT/Statistic.h"
24#include "llvm/Analysis/BlockFrequencyInfo.h"
25#include "llvm/Analysis/BranchProbabilityInfo.h"
26#include "llvm/Analysis/ConstantFolding.h"
27#include "llvm/Analysis/InstructionSimplify.h"
28#include "llvm/Analysis/LoopInfo.h"
29#include "llvm/Analysis/MemoryBuiltins.h"
30#include "llvm/Analysis/ProfileSummaryInfo.h"
31#include "llvm/Analysis/TargetLibraryInfo.h"
32#include "llvm/Analysis/TargetTransformInfo.h"
33#include "llvm/Analysis/ValueTracking.h"
34#include "llvm/Analysis/VectorUtils.h"
35#include "llvm/CodeGen/Analysis.h"
36#include "llvm/CodeGen/ISDOpcodes.h"
37#include "llvm/CodeGen/SelectionDAGNodes.h"
38#include "llvm/CodeGen/TargetLowering.h"
39#include "llvm/CodeGen/TargetPassConfig.h"
40#include "llvm/CodeGen/TargetSubtargetInfo.h"
41#include "llvm/CodeGen/ValueTypes.h"
42#include "llvm/Config/llvm-config.h"
43#include "llvm/IR/Argument.h"
44#include "llvm/IR/Attributes.h"
45#include "llvm/IR/BasicBlock.h"
46#include "llvm/IR/CallSite.h"
47#include "llvm/IR/Constant.h"
48#include "llvm/IR/Constants.h"
49#include "llvm/IR/DataLayout.h"
50#include "llvm/IR/DerivedTypes.h"
51#include "llvm/IR/Dominators.h"
52#include "llvm/IR/Function.h"
53#include "llvm/IR/GetElementPtrTypeIterator.h"
54#include "llvm/IR/GlobalValue.h"
55#include "llvm/IR/GlobalVariable.h"
56#include "llvm/IR/IRBuilder.h"
57#include "llvm/IR/InlineAsm.h"
58#include "llvm/IR/InstrTypes.h"
59#include "llvm/IR/Instruction.h"
60#include "llvm/IR/Instructions.h"
61#include "llvm/IR/IntrinsicInst.h"
62#include "llvm/IR/Intrinsics.h"
63#include "llvm/IR/IntrinsicsAArch64.h"
64#include "llvm/IR/IntrinsicsX86.h"
65#include "llvm/IR/LLVMContext.h"
66#include "llvm/IR/MDBuilder.h"
67#include "llvm/IR/Module.h"
68#include "llvm/IR/Operator.h"
69#include "llvm/IR/PatternMatch.h"
70#include "llvm/IR/Statepoint.h"
71#include "llvm/IR/Type.h"
72#include "llvm/IR/Use.h"
73#include "llvm/IR/User.h"
74#include "llvm/IR/Value.h"
75#include "llvm/IR/ValueHandle.h"
76#include "llvm/IR/ValueMap.h"
77#include "llvm/InitializePasses.h"
78#include "llvm/Pass.h"
79#include "llvm/Support/BlockFrequency.h"
80#include "llvm/Support/BranchProbability.h"
81#include "llvm/Support/Casting.h"
82#include "llvm/Support/CommandLine.h"
83#include "llvm/Support/Compiler.h"
84#include "llvm/Support/Debug.h"
85#include "llvm/Support/ErrorHandling.h"
86#include "llvm/Support/MachineValueType.h"
87#include "llvm/Support/MathExtras.h"
88#include "llvm/Support/raw_ostream.h"
89#include "llvm/Target/TargetMachine.h"
90#include "llvm/Target/TargetOptions.h"
91#include "llvm/Transforms/Utils/BasicBlockUtils.h"
92#include "llvm/Transforms/Utils/BypassSlowDivision.h"
93#include "llvm/Transforms/Utils/Local.h"
94#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
95#include "llvm/Transforms/Utils/SizeOpts.h"
96#include <algorithm>
97#include <cassert>
98#include <cstdint>
99#include <iterator>
100#include <limits>
101#include <memory>
102#include <utility>
103#include <vector>
104
105using namespace llvm;
106using namespace llvm::PatternMatch;
107
108#define DEBUG_TYPE"codegenprepare" "codegenprepare"
109
110STATISTIC(NumBlocksElim, "Number of blocks eliminated")static llvm::Statistic NumBlocksElim = {"codegenprepare", "NumBlocksElim"
, "Number of blocks eliminated"}
;
111STATISTIC(NumPHIsElim, "Number of trivial PHIs eliminated")static llvm::Statistic NumPHIsElim = {"codegenprepare", "NumPHIsElim"
, "Number of trivial PHIs eliminated"}
;
112STATISTIC(NumGEPsElim, "Number of GEPs converted to casts")static llvm::Statistic NumGEPsElim = {"codegenprepare", "NumGEPsElim"
, "Number of GEPs converted to casts"}
;
113STATISTIC(NumCmpUses, "Number of uses of Cmp expressions replaced with uses of "static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses"
, "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps"
}
114 "sunken Cmps")static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses"
, "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps"
}
;
115STATISTIC(NumCastUses, "Number of uses of Cast expressions replaced with uses "static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses"
, "Number of uses of Cast expressions replaced with uses " "of sunken Casts"
}
116 "of sunken Casts")static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses"
, "Number of uses of Cast expressions replaced with uses " "of sunken Casts"
}
;
117STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
}
118 "computations were sunk")static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
}
;
119STATISTIC(NumMemoryInstsPhiCreated,static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions"}
120 "Number of phis created when address "static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions"}
121 "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions"}
;
122STATISTIC(NumMemoryInstsSelectCreated,static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions"}
123 "Number of select created when address "static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions"}
124 "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions"}
;
125STATISTIC(NumExtsMoved, "Number of [s|z]ext instructions combined with loads")static llvm::Statistic NumExtsMoved = {"codegenprepare", "NumExtsMoved"
, "Number of [s|z]ext instructions combined with loads"}
;
126STATISTIC(NumExtUses, "Number of uses of [s|z]ext instructions optimized")static llvm::Statistic NumExtUses = {"codegenprepare", "NumExtUses"
, "Number of uses of [s|z]ext instructions optimized"}
;
127STATISTIC(NumAndsAdded,static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded"
, "Number of and mask instructions added to form ext loads"}
128 "Number of and mask instructions added to form ext loads")static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded"
, "Number of and mask instructions added to form ext loads"}
;
129STATISTIC(NumAndUses, "Number of uses of and mask instructions optimized")static llvm::Statistic NumAndUses = {"codegenprepare", "NumAndUses"
, "Number of uses of and mask instructions optimized"}
;
130STATISTIC(NumRetsDup, "Number of return instructions duplicated")static llvm::Statistic NumRetsDup = {"codegenprepare", "NumRetsDup"
, "Number of return instructions duplicated"}
;
131STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved")static llvm::Statistic NumDbgValueMoved = {"codegenprepare", "NumDbgValueMoved"
, "Number of debug value instructions moved"}
;
132STATISTIC(NumSelectsExpanded, "Number of selects turned into branches")static llvm::Statistic NumSelectsExpanded = {"codegenprepare"
, "NumSelectsExpanded", "Number of selects turned into branches"
}
;
133STATISTIC(NumStoreExtractExposed, "Number of store(extractelement) exposed")static llvm::Statistic NumStoreExtractExposed = {"codegenprepare"
, "NumStoreExtractExposed", "Number of store(extractelement) exposed"
}
;
134
135static cl::opt<bool> DisableBranchOpts(
136 "disable-cgp-branch-opts", cl::Hidden, cl::init(false),
137 cl::desc("Disable branch optimizations in CodeGenPrepare"));
138
139static cl::opt<bool>
140 DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false),
141 cl::desc("Disable GC optimizations in CodeGenPrepare"));
142
143static cl::opt<bool> DisableSelectToBranch(
144 "disable-cgp-select2branch", cl::Hidden, cl::init(false),
145 cl::desc("Disable select to branch conversion."));
146
147static cl::opt<bool> AddrSinkUsingGEPs(
148 "addr-sink-using-gep", cl::Hidden, cl::init(true),
149 cl::desc("Address sinking in CGP using GEPs."));
150
151static cl::opt<bool> EnableAndCmpSinking(
152 "enable-andcmp-sinking", cl::Hidden, cl::init(true),
153 cl::desc("Enable sinkinig and/cmp into branches."));
154
155static cl::opt<bool> DisableStoreExtract(
156 "disable-cgp-store-extract", cl::Hidden, cl::init(false),
157 cl::desc("Disable store(extract) optimizations in CodeGenPrepare"));
158
159static cl::opt<bool> StressStoreExtract(
160 "stress-cgp-store-extract", cl::Hidden, cl::init(false),
161 cl::desc("Stress test store(extract) optimizations in CodeGenPrepare"));
162
163static cl::opt<bool> DisableExtLdPromotion(
164 "disable-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
165 cl::desc("Disable ext(promotable(ld)) -> promoted(ext(ld)) optimization in "
166 "CodeGenPrepare"));
167
168static cl::opt<bool> StressExtLdPromotion(
169 "stress-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
170 cl::desc("Stress test ext(promotable(ld)) -> promoted(ext(ld)) "
171 "optimization in CodeGenPrepare"));
172
173static cl::opt<bool> DisablePreheaderProtect(
174 "disable-preheader-prot", cl::Hidden, cl::init(false),
175 cl::desc("Disable protection against removing loop preheaders"));
176
177static cl::opt<bool> ProfileGuidedSectionPrefix(
178 "profile-guided-section-prefix", cl::Hidden, cl::init(true), cl::ZeroOrMore,
179 cl::desc("Use profile info to add section prefix for hot/cold functions"));
180
181static cl::opt<unsigned> FreqRatioToSkipMerge(
182 "cgp-freq-ratio-to-skip-merge", cl::Hidden, cl::init(2),
183 cl::desc("Skip merging empty blocks if (frequency of empty block) / "
184 "(frequency of destination block) is greater than this ratio"));
185
186static cl::opt<bool> ForceSplitStore(
187 "force-split-store", cl::Hidden, cl::init(false),
188 cl::desc("Force store splitting no matter what the target query says."));
189
190static cl::opt<bool>
191EnableTypePromotionMerge("cgp-type-promotion-merge", cl::Hidden,
192 cl::desc("Enable merging of redundant sexts when one is dominating"
193 " the other."), cl::init(true));
194
195static cl::opt<bool> DisableComplexAddrModes(
196 "disable-complex-addr-modes", cl::Hidden, cl::init(false),
197 cl::desc("Disables combining addressing modes with different parts "
198 "in optimizeMemoryInst."));
199
200static cl::opt<bool>
201AddrSinkNewPhis("addr-sink-new-phis", cl::Hidden, cl::init(false),
202 cl::desc("Allow creation of Phis in Address sinking."));
203
204static cl::opt<bool>
205AddrSinkNewSelects("addr-sink-new-select", cl::Hidden, cl::init(true),
206 cl::desc("Allow creation of selects in Address sinking."));
207
208static cl::opt<bool> AddrSinkCombineBaseReg(
209 "addr-sink-combine-base-reg", cl::Hidden, cl::init(true),
210 cl::desc("Allow combining of BaseReg field in Address sinking."));
211
212static cl::opt<bool> AddrSinkCombineBaseGV(
213 "addr-sink-combine-base-gv", cl::Hidden, cl::init(true),
214 cl::desc("Allow combining of BaseGV field in Address sinking."));
215
216static cl::opt<bool> AddrSinkCombineBaseOffs(
217 "addr-sink-combine-base-offs", cl::Hidden, cl::init(true),
218 cl::desc("Allow combining of BaseOffs field in Address sinking."));
219
220static cl::opt<bool> AddrSinkCombineScaledReg(
221 "addr-sink-combine-scaled-reg", cl::Hidden, cl::init(true),
222 cl::desc("Allow combining of ScaledReg field in Address sinking."));
223
224static cl::opt<bool>
225 EnableGEPOffsetSplit("cgp-split-large-offset-gep", cl::Hidden,
226 cl::init(true),
227 cl::desc("Enable splitting large offset of GEP."));
228
229static cl::opt<bool> EnableICMP_EQToICMP_ST(
230 "cgp-icmp-eq2icmp-st", cl::Hidden, cl::init(false),
231 cl::desc("Enable ICMP_EQ to ICMP_S(L|G)T conversion."));
232
233namespace {
234
235enum ExtType {
236 ZeroExtension, // Zero extension has been seen.
237 SignExtension, // Sign extension has been seen.
238 BothExtension // This extension type is used if we saw sext after
239 // ZeroExtension had been set, or if we saw zext after
240 // SignExtension had been set. It makes the type
241 // information of a promoted instruction invalid.
242};
243
244using SetOfInstrs = SmallPtrSet<Instruction *, 16>;
245using TypeIsSExt = PointerIntPair<Type *, 2, ExtType>;
246using InstrToOrigTy = DenseMap<Instruction *, TypeIsSExt>;
247using SExts = SmallVector<Instruction *, 16>;
248using ValueToSExts = DenseMap<Value *, SExts>;
249
250class TypePromotionTransaction;
251
252 class CodeGenPrepare : public FunctionPass {
253 const TargetMachine *TM = nullptr;
254 const TargetSubtargetInfo *SubtargetInfo;
255 const TargetLowering *TLI = nullptr;
256 const TargetRegisterInfo *TRI;
257 const TargetTransformInfo *TTI = nullptr;
258 const TargetLibraryInfo *TLInfo;
259 const LoopInfo *LI;
260 std::unique_ptr<BlockFrequencyInfo> BFI;
261 std::unique_ptr<BranchProbabilityInfo> BPI;
262 ProfileSummaryInfo *PSI;
263
264 /// As we scan instructions optimizing them, this is the next instruction
265 /// to optimize. Transforms that can invalidate this should update it.
266 BasicBlock::iterator CurInstIterator;
267
268 /// Keeps track of non-local addresses that have been sunk into a block.
269 /// This allows us to avoid inserting duplicate code for blocks with
270 /// multiple load/stores of the same address. The usage of WeakTrackingVH
271 /// enables SunkAddrs to be treated as a cache whose entries can be
272 /// invalidated if a sunken address computation has been erased.
273 ValueMap<Value*, WeakTrackingVH> SunkAddrs;
274
275 /// Keeps track of all instructions inserted for the current function.
276 SetOfInstrs InsertedInsts;
277
278 /// Keeps track of the type of the related instruction before their
279 /// promotion for the current function.
280 InstrToOrigTy PromotedInsts;
281
282 /// Keep track of instructions removed during promotion.
283 SetOfInstrs RemovedInsts;
284
285 /// Keep track of sext chains based on their initial value.
286 DenseMap<Value *, Instruction *> SeenChainsForSExt;
287
288 /// Keep track of GEPs accessing the same data structures such as structs or
289 /// arrays that are candidates to be split later because of their large
290 /// size.
291 MapVector<
292 AssertingVH<Value>,
293 SmallVector<std::pair<AssertingVH<GetElementPtrInst>, int64_t>, 32>>
294 LargeOffsetGEPMap;
295
296 /// Keep track of new GEP base after splitting the GEPs having large offset.
297 SmallSet<AssertingVH<Value>, 2> NewGEPBases;
298
299 /// Map serial numbers to Large offset GEPs.
300 DenseMap<AssertingVH<GetElementPtrInst>, int> LargeOffsetGEPID;
301
302 /// Keep track of SExt promoted.
303 ValueToSExts ValToSExtendedUses;
304
305 /// True if the function has the OptSize attribute.
306 bool OptSize;
307
308 /// DataLayout for the Function being processed.
309 const DataLayout *DL = nullptr;
310
311 /// Building the dominator tree can be expensive, so we only build it
312 /// lazily and update it when required.
313 std::unique_ptr<DominatorTree> DT;
314
315 public:
316 static char ID; // Pass identification, replacement for typeid
317
318 CodeGenPrepare() : FunctionPass(ID) {
319 initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
320 }
321
322 bool runOnFunction(Function &F) override;
323
324 StringRef getPassName() const override { return "CodeGen Prepare"; }
325
326 void getAnalysisUsage(AnalysisUsage &AU) const override {
327 // FIXME: When we can selectively preserve passes, preserve the domtree.
328 AU.addRequired<ProfileSummaryInfoWrapperPass>();
329 AU.addRequired<TargetLibraryInfoWrapperPass>();
330 AU.addRequired<TargetPassConfig>();
331 AU.addRequired<TargetTransformInfoWrapperPass>();
332 AU.addRequired<LoopInfoWrapperPass>();
333 }
334
335 private:
336 template <typename F>
337 void resetIteratorIfInvalidatedWhileCalling(BasicBlock *BB, F f) {
338 // Substituting can cause recursive simplifications, which can invalidate
339 // our iterator. Use a WeakTrackingVH to hold onto it in case this
340 // happens.
341 Value *CurValue = &*CurInstIterator;
342 WeakTrackingVH IterHandle(CurValue);
343
344 f();
345
346 // If the iterator instruction was recursively deleted, start over at the
347 // start of the block.
348 if (IterHandle != CurValue) {
349 CurInstIterator = BB->begin();
350 SunkAddrs.clear();
351 }
352 }
353
354 // Get the DominatorTree, building if necessary.
355 DominatorTree &getDT(Function &F) {
356 if (!DT)
357 DT = std::make_unique<DominatorTree>(F);
358 return *DT;
359 }
360
361 bool eliminateFallThrough(Function &F);
362 bool eliminateMostlyEmptyBlocks(Function &F);
363 BasicBlock *findDestBlockOfMergeableEmptyBlock(BasicBlock *BB);
364 bool canMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
365 void eliminateMostlyEmptyBlock(BasicBlock *BB);
366 bool isMergingEmptyBlockProfitable(BasicBlock *BB, BasicBlock *DestBB,
367 bool isPreheader);
368 bool optimizeBlock(BasicBlock &BB, bool &ModifiedDT);
369 bool optimizeInst(Instruction *I, bool &ModifiedDT);
370 bool optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
371 Type *AccessTy, unsigned AddrSpace);
372 bool optimizeInlineAsmInst(CallInst *CS);
373 bool optimizeCallInst(CallInst *CI, bool &ModifiedDT);
374 bool optimizeExt(Instruction *&I);
375 bool optimizeExtUses(Instruction *I);
376 bool optimizeLoadExt(LoadInst *Load);
377 bool optimizeShiftInst(BinaryOperator *BO);
378 bool optimizeSelectInst(SelectInst *SI);
379 bool optimizeShuffleVectorInst(ShuffleVectorInst *SVI);
380 bool optimizeSwitchInst(SwitchInst *SI);
381 bool optimizeExtractElementInst(Instruction *Inst);
382 bool dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT);
383 bool fixupDbgValue(Instruction *I);
384 bool placeDbgValues(Function &F);
385 bool canFormExtLd(const SmallVectorImpl<Instruction *> &MovedExts,
386 LoadInst *&LI, Instruction *&Inst, bool HasPromoted);
387 bool tryToPromoteExts(TypePromotionTransaction &TPT,
388 const SmallVectorImpl<Instruction *> &Exts,
389 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
390 unsigned CreatedInstsCost = 0);
391 bool mergeSExts(Function &F);
392 bool splitLargeGEPOffsets();
393 bool performAddressTypePromotion(
394 Instruction *&Inst,
395 bool AllowPromotionWithoutCommonHeader,
396 bool HasPromoted, TypePromotionTransaction &TPT,
397 SmallVectorImpl<Instruction *> &SpeculativelyMovedExts);
398 bool splitBranchCondition(Function &F, bool &ModifiedDT);
399 bool simplifyOffsetableRelocate(Instruction &I);
400
401 bool tryToSinkFreeOperands(Instruction *I);
402 bool replaceMathCmpWithIntrinsic(BinaryOperator *BO, Value *Arg0,
403 Value *Arg1, CmpInst *Cmp,
404 Intrinsic::ID IID);
405 bool optimizeCmp(CmpInst *Cmp, bool &ModifiedDT);
406 bool combineToUSubWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
407 bool combineToUAddWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
408 };
409
410} // end anonymous namespace
411
412char CodeGenPrepare::ID = 0;
413
414INITIALIZE_PASS_BEGIN(CodeGenPrepare, DEBUG_TYPE,static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
415 "Optimize for code generation", false, false)static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
416INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)initializeProfileSummaryInfoWrapperPassPass(Registry);
417INITIALIZE_PASS_END(CodeGenPrepare, DEBUG_TYPE,PassInfo *PI = new PassInfo( "Optimize for code generation", "codegenprepare"
, &CodeGenPrepare::ID, PassInfo::NormalCtor_t(callDefaultCtor
<CodeGenPrepare>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeCodeGenPreparePassFlag
; void llvm::initializeCodeGenPreparePass(PassRegistry &Registry
) { llvm::call_once(InitializeCodeGenPreparePassFlag, initializeCodeGenPreparePassOnce
, std::ref(Registry)); }
418 "Optimize for code generation", false, false)PassInfo *PI = new PassInfo( "Optimize for code generation", "codegenprepare"
, &CodeGenPrepare::ID, PassInfo::NormalCtor_t(callDefaultCtor
<CodeGenPrepare>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeCodeGenPreparePassFlag
; void llvm::initializeCodeGenPreparePass(PassRegistry &Registry
) { llvm::call_once(InitializeCodeGenPreparePassFlag, initializeCodeGenPreparePassOnce
, std::ref(Registry)); }
419
420FunctionPass *llvm::createCodeGenPreparePass() { return new CodeGenPrepare(); }
421
422bool CodeGenPrepare::runOnFunction(Function &F) {
423 if (skipFunction(F))
424 return false;
425
426 DL = &F.getParent()->getDataLayout();
427
428 bool EverMadeChange = false;
429 // Clear per function information.
430 InsertedInsts.clear();
431 PromotedInsts.clear();
432
433 TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
434 SubtargetInfo = TM->getSubtargetImpl(F);
435 TLI = SubtargetInfo->getTargetLowering();
436 TRI = SubtargetInfo->getRegisterInfo();
437 TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
438 TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
439 LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
440 BPI.reset(new BranchProbabilityInfo(F, *LI));
441 BFI.reset(new BlockFrequencyInfo(F, *BPI, *LI));
442 PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
443 OptSize = F.hasOptSize();
444 if (ProfileGuidedSectionPrefix) {
445 if (PSI->isFunctionHotInCallGraph(&F, *BFI))
446 F.setSectionPrefix(".hot");
447 else if (PSI->isFunctionColdInCallGraph(&F, *BFI))
448 F.setSectionPrefix(".unlikely");
449 }
450
451 /// This optimization identifies DIV instructions that can be
452 /// profitably bypassed and carried out with a shorter, faster divide.
453 if (!OptSize && !PSI->hasHugeWorkingSetSize() && TLI->isSlowDivBypassed()) {
454 const DenseMap<unsigned int, unsigned int> &BypassWidths =
455 TLI->getBypassSlowDivWidths();
456 BasicBlock* BB = &*F.begin();
457 while (BB != nullptr) {
458 // bypassSlowDivision may create new BBs, but we don't want to reapply the
459 // optimization to those blocks.
460 BasicBlock* Next = BB->getNextNode();
461 // F.hasOptSize is already checked in the outer if statement.
462 if (!llvm::shouldOptimizeForSize(BB, PSI, BFI.get()))
463 EverMadeChange |= bypassSlowDivision(BB, BypassWidths);
464 BB = Next;
465 }
466 }
467
468 // Eliminate blocks that contain only PHI nodes and an
469 // unconditional branch.
470 EverMadeChange |= eliminateMostlyEmptyBlocks(F);
471
472 bool ModifiedDT = false;
473 if (!DisableBranchOpts)
474 EverMadeChange |= splitBranchCondition(F, ModifiedDT);
475
476 // Split some critical edges where one of the sources is an indirect branch,
477 // to help generate sane code for PHIs involving such edges.
478 EverMadeChange |= SplitIndirectBrCriticalEdges(F);
479
480 bool MadeChange = true;
481 while (MadeChange) {
482 MadeChange = false;
483 DT.reset();
484 for (Function::iterator I = F.begin(); I != F.end(); ) {
485 BasicBlock *BB = &*I++;
486 bool ModifiedDTOnIteration = false;
487 MadeChange |= optimizeBlock(*BB, ModifiedDTOnIteration);
488
489 // Restart BB iteration if the dominator tree of the Function was changed
490 if (ModifiedDTOnIteration)
491 break;
492 }
493 if (EnableTypePromotionMerge && !ValToSExtendedUses.empty())
494 MadeChange |= mergeSExts(F);
495 if (!LargeOffsetGEPMap.empty())
496 MadeChange |= splitLargeGEPOffsets();
497
498 // Really free removed instructions during promotion.
499 for (Instruction *I : RemovedInsts)
500 I->deleteValue();
501
502 EverMadeChange |= MadeChange;
503 SeenChainsForSExt.clear();
504 ValToSExtendedUses.clear();
505 RemovedInsts.clear();
506 LargeOffsetGEPMap.clear();
507 LargeOffsetGEPID.clear();
508 }
509
510 SunkAddrs.clear();
511
512 if (!DisableBranchOpts) {
513 MadeChange = false;
514 // Use a set vector to get deterministic iteration order. The order the
515 // blocks are removed may affect whether or not PHI nodes in successors
516 // are removed.
517 SmallSetVector<BasicBlock*, 8> WorkList;
518 for (BasicBlock &BB : F) {
519 SmallVector<BasicBlock *, 2> Successors(succ_begin(&BB), succ_end(&BB));
520 MadeChange |= ConstantFoldTerminator(&BB, true);
521 if (!MadeChange) continue;
522
523 for (SmallVectorImpl<BasicBlock*>::iterator
524 II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
525 if (pred_begin(*II) == pred_end(*II))
526 WorkList.insert(*II);
527 }
528
529 // Delete the dead blocks and any of their dead successors.
530 MadeChange |= !WorkList.empty();
531 while (!WorkList.empty()) {
532 BasicBlock *BB = WorkList.pop_back_val();
533 SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
534
535 DeleteDeadBlock(BB);
536
537 for (SmallVectorImpl<BasicBlock*>::iterator
538 II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
539 if (pred_begin(*II) == pred_end(*II))
540 WorkList.insert(*II);
541 }
542
543 // Merge pairs of basic blocks with unconditional branches, connected by
544 // a single edge.
545 if (EverMadeChange || MadeChange)
546 MadeChange |= eliminateFallThrough(F);
547
548 EverMadeChange |= MadeChange;
549 }
550
551 if (!DisableGCOpts) {
552 SmallVector<Instruction *, 2> Statepoints;
553 for (BasicBlock &BB : F)
554 for (Instruction &I : BB)
555 if (isStatepoint(I))
556 Statepoints.push_back(&I);
557 for (auto &I : Statepoints)
558 EverMadeChange |= simplifyOffsetableRelocate(*I);
559 }
560
561 // Do this last to clean up use-before-def scenarios introduced by other
562 // preparatory transforms.
563 EverMadeChange |= placeDbgValues(F);
564
565 return EverMadeChange;
566}
567
568/// Merge basic blocks which are connected by a single edge, where one of the
569/// basic blocks has a single successor pointing to the other basic block,
570/// which has a single predecessor.
571bool CodeGenPrepare::eliminateFallThrough(Function &F) {
572 bool Changed = false;
573 // Scan all of the blocks in the function, except for the entry block.
574 // Use a temporary array to avoid iterator being invalidated when
575 // deleting blocks.
576 SmallVector<WeakTrackingVH, 16> Blocks;
577 for (auto &Block : llvm::make_range(std::next(F.begin()), F.end()))
578 Blocks.push_back(&Block);
579
580 for (auto &Block : Blocks) {
581 auto *BB = cast_or_null<BasicBlock>(Block);
582 if (!BB)
583 continue;
584 // If the destination block has a single pred, then this is a trivial
585 // edge, just collapse it.
586 BasicBlock *SinglePred = BB->getSinglePredecessor();
587
588 // Don't merge if BB's address is taken.
589 if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue;
590
591 BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
592 if (Term && !Term->isConditional()) {
593 Changed = true;
594 LLVM_DEBUG(dbgs() << "To merge:\n" << *BB << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "To merge:\n" << *
BB << "\n\n\n"; } } while (false)
;
595
596 // Merge BB into SinglePred and delete it.
597 MergeBlockIntoPredecessor(BB);
598 }
599 }
600 return Changed;
601}
602
603/// Find a destination block from BB if BB is mergeable empty block.
604BasicBlock *CodeGenPrepare::findDestBlockOfMergeableEmptyBlock(BasicBlock *BB) {
605 // If this block doesn't end with an uncond branch, ignore it.
606 BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
607 if (!BI || !BI->isUnconditional())
608 return nullptr;
609
610 // If the instruction before the branch (skipping debug info) isn't a phi
611 // node, then other stuff is happening here.
612 BasicBlock::iterator BBI = BI->getIterator();
613 if (BBI != BB->begin()) {
614 --BBI;
615 while (isa<DbgInfoIntrinsic>(BBI)) {
616 if (BBI == BB->begin())
617 break;
618 --BBI;
619 }
620 if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI))
621 return nullptr;
622 }
623
624 // Do not break infinite loops.
625 BasicBlock *DestBB = BI->getSuccessor(0);
626 if (DestBB == BB)
627 return nullptr;
628
629 if (!canMergeBlocks(BB, DestBB))
630 DestBB = nullptr;
631
632 return DestBB;
633}
634
635/// Eliminate blocks that contain only PHI nodes, debug info directives, and an
636/// unconditional branch. Passes before isel (e.g. LSR/loopsimplify) often split
637/// edges in ways that are non-optimal for isel. Start by eliminating these
638/// blocks so we can split them the way we want them.
639bool CodeGenPrepare::eliminateMostlyEmptyBlocks(Function &F) {
640 SmallPtrSet<BasicBlock *, 16> Preheaders;
641 SmallVector<Loop *, 16> LoopList(LI->begin(), LI->end());
642 while (!LoopList.empty()) {
643 Loop *L = LoopList.pop_back_val();
644 LoopList.insert(LoopList.end(), L->begin(), L->end());
645 if (BasicBlock *Preheader = L->getLoopPreheader())
646 Preheaders.insert(Preheader);
647 }
648
649 bool MadeChange = false;
650 // Copy blocks into a temporary array to avoid iterator invalidation issues
651 // as we remove them.
652 // Note that this intentionally skips the entry block.
653 SmallVector<WeakTrackingVH, 16> Blocks;
654 for (auto &Block : llvm::make_range(std::next(F.begin()), F.end()))
655 Blocks.push_back(&Block);
656
657 for (auto &Block : Blocks) {
658 BasicBlock *BB = cast_or_null<BasicBlock>(Block);
659 if (!BB)
660 continue;
661 BasicBlock *DestBB = findDestBlockOfMergeableEmptyBlock(BB);
662 if (!DestBB ||
663 !isMergingEmptyBlockProfitable(BB, DestBB, Preheaders.count(BB)))
664 continue;
665
666 eliminateMostlyEmptyBlock(BB);
667 MadeChange = true;
668 }
669 return MadeChange;
670}
671
672bool CodeGenPrepare::isMergingEmptyBlockProfitable(BasicBlock *BB,
673 BasicBlock *DestBB,
674 bool isPreheader) {
675 // Do not delete loop preheaders if doing so would create a critical edge.
676 // Loop preheaders can be good locations to spill registers. If the
677 // preheader is deleted and we create a critical edge, registers may be
678 // spilled in the loop body instead.
679 if (!DisablePreheaderProtect && isPreheader &&
680 !(BB->getSinglePredecessor() &&
681 BB->getSinglePredecessor()->getSingleSuccessor()))
682 return false;
683
684 // Skip merging if the block's successor is also a successor to any callbr
685 // that leads to this block.
686 // FIXME: Is this really needed? Is this a correctness issue?
687 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
688 if (auto *CBI = dyn_cast<CallBrInst>((*PI)->getTerminator()))
689 for (unsigned i = 0, e = CBI->getNumSuccessors(); i != e; ++i)
690 if (DestBB == CBI->getSuccessor(i))
691 return false;
692 }
693
694 // Try to skip merging if the unique predecessor of BB is terminated by a
695 // switch or indirect branch instruction, and BB is used as an incoming block
696 // of PHIs in DestBB. In such case, merging BB and DestBB would cause ISel to
697 // add COPY instructions in the predecessor of BB instead of BB (if it is not
698 // merged). Note that the critical edge created by merging such blocks wont be
699 // split in MachineSink because the jump table is not analyzable. By keeping
700 // such empty block (BB), ISel will place COPY instructions in BB, not in the
701 // predecessor of BB.
702 BasicBlock *Pred = BB->getUniquePredecessor();
703 if (!Pred ||
704 !(isa<SwitchInst>(Pred->getTerminator()) ||
705 isa<IndirectBrInst>(Pred->getTerminator())))
706 return true;
707
708 if (BB->getTerminator() != BB->getFirstNonPHIOrDbg())
709 return true;
710
711 // We use a simple cost heuristic which determine skipping merging is
712 // profitable if the cost of skipping merging is less than the cost of
713 // merging : Cost(skipping merging) < Cost(merging BB), where the
714 // Cost(skipping merging) is Freq(BB) * (Cost(Copy) + Cost(Branch)), and
715 // the Cost(merging BB) is Freq(Pred) * Cost(Copy).
716 // Assuming Cost(Copy) == Cost(Branch), we could simplify it to :
717 // Freq(Pred) / Freq(BB) > 2.
718 // Note that if there are multiple empty blocks sharing the same incoming
719 // value for the PHIs in the DestBB, we consider them together. In such
720 // case, Cost(merging BB) will be the sum of their frequencies.
721
722 if (!isa<PHINode>(DestBB->begin()))
723 return true;
724
725 SmallPtrSet<BasicBlock *, 16> SameIncomingValueBBs;
726
727 // Find all other incoming blocks from which incoming values of all PHIs in
728 // DestBB are the same as the ones from BB.
729 for (pred_iterator PI = pred_begin(DestBB), E = pred_end(DestBB); PI != E;
730 ++PI) {
731 BasicBlock *DestBBPred = *PI;
732 if (DestBBPred == BB)
733 continue;
734
735 if (llvm::all_of(DestBB->phis(), [&](const PHINode &DestPN) {
736 return DestPN.getIncomingValueForBlock(BB) ==
737 DestPN.getIncomingValueForBlock(DestBBPred);
738 }))
739 SameIncomingValueBBs.insert(DestBBPred);
740 }
741
742 // See if all BB's incoming values are same as the value from Pred. In this
743 // case, no reason to skip merging because COPYs are expected to be place in
744 // Pred already.
745 if (SameIncomingValueBBs.count(Pred))
746 return true;
747
748 BlockFrequency PredFreq = BFI->getBlockFreq(Pred);
749 BlockFrequency BBFreq = BFI->getBlockFreq(BB);
750
751 for (auto SameValueBB : SameIncomingValueBBs)
752 if (SameValueBB->getUniquePredecessor() == Pred &&
753 DestBB == findDestBlockOfMergeableEmptyBlock(SameValueBB))
754 BBFreq += BFI->getBlockFreq(SameValueBB);
755
756 return PredFreq.getFrequency() <=
757 BBFreq.getFrequency() * FreqRatioToSkipMerge;
758}
759
760/// Return true if we can merge BB into DestBB if there is a single
761/// unconditional branch between them, and BB contains no other non-phi
762/// instructions.
763bool CodeGenPrepare::canMergeBlocks(const BasicBlock *BB,
764 const BasicBlock *DestBB) const {
765 // We only want to eliminate blocks whose phi nodes are used by phi nodes in
766 // the successor. If there are more complex condition (e.g. preheaders),
767 // don't mess around with them.
768 for (const PHINode &PN : BB->phis()) {
769 for (const User *U : PN.users()) {
770 const Instruction *UI = cast<Instruction>(U);
771 if (UI->getParent() != DestBB || !isa<PHINode>(UI))
772 return false;
773 // If User is inside DestBB block and it is a PHINode then check
774 // incoming value. If incoming value is not from BB then this is
775 // a complex condition (e.g. preheaders) we want to avoid here.
776 if (UI->getParent() == DestBB) {
777 if (const PHINode *UPN = dyn_cast<PHINode>(UI))
778 for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
779 Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
780 if (Insn && Insn->getParent() == BB &&
781 Insn->getParent() != UPN->getIncomingBlock(I))
782 return false;
783 }
784 }
785 }
786 }
787
788 // If BB and DestBB contain any common predecessors, then the phi nodes in BB
789 // and DestBB may have conflicting incoming values for the block. If so, we
790 // can't merge the block.
791 const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
792 if (!DestBBPN) return true; // no conflict.
793
794 // Collect the preds of BB.
795 SmallPtrSet<const BasicBlock*, 16> BBPreds;
796 if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
797 // It is faster to get preds from a PHI than with pred_iterator.
798 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
799 BBPreds.insert(BBPN->getIncomingBlock(i));
800 } else {
801 BBPreds.insert(pred_begin(BB), pred_end(BB));
802 }
803
804 // Walk the preds of DestBB.
805 for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
806 BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
807 if (BBPreds.count(Pred)) { // Common predecessor?
808 for (const PHINode &PN : DestBB->phis()) {
809 const Value *V1 = PN.getIncomingValueForBlock(Pred);
810 const Value *V2 = PN.getIncomingValueForBlock(BB);
811
812 // If V2 is a phi node in BB, look up what the mapped value will be.
813 if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
814 if (V2PN->getParent() == BB)
815 V2 = V2PN->getIncomingValueForBlock(Pred);
816
817 // If there is a conflict, bail out.
818 if (V1 != V2) return false;
819 }
820 }
821 }
822
823 return true;
824}
825
826/// Eliminate a basic block that has only phi's and an unconditional branch in
827/// it.
828void CodeGenPrepare::eliminateMostlyEmptyBlock(BasicBlock *BB) {
829 BranchInst *BI = cast<BranchInst>(BB->getTerminator());
830 BasicBlock *DestBB = BI->getSuccessor(0);
831
832 LLVM_DEBUG(dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"
<< *BB << *DestBB; } } while (false)
833 << *BB << *DestBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"
<< *BB << *DestBB; } } while (false)
;
834
835 // If the destination block has a single pred, then this is a trivial edge,
836 // just collapse it.
837 if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
838 if (SinglePred != DestBB) {
839 assert(SinglePred == BB &&((SinglePred == BB && "Single predecessor not the same as predecessor"
) ? static_cast<void> (0) : __assert_fail ("SinglePred == BB && \"Single predecessor not the same as predecessor\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 840, __PRETTY_FUNCTION__))
840 "Single predecessor not the same as predecessor")((SinglePred == BB && "Single predecessor not the same as predecessor"
) ? static_cast<void> (0) : __assert_fail ("SinglePred == BB && \"Single predecessor not the same as predecessor\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 840, __PRETTY_FUNCTION__))
;
841 // Merge DestBB into SinglePred/BB and delete it.
842 MergeBlockIntoPredecessor(DestBB);
843 // Note: BB(=SinglePred) will not be deleted on this path.
844 // DestBB(=its single successor) is the one that was deleted.
845 LLVM_DEBUG(dbgs() << "AFTER:\n" << *SinglePred << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "AFTER:\n" << *SinglePred
<< "\n\n\n"; } } while (false)
;
846 return;
847 }
848 }
849
850 // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
851 // to handle the new incoming edges it is about to have.
852 for (PHINode &PN : DestBB->phis()) {
853 // Remove the incoming value for BB, and remember it.
854 Value *InVal = PN.removeIncomingValue(BB, false);
855
856 // Two options: either the InVal is a phi node defined in BB or it is some
857 // value that dominates BB.
858 PHINode *InValPhi = dyn_cast<PHINode>(InVal);
859 if (InValPhi && InValPhi->getParent() == BB) {
860 // Add all of the input values of the input PHI as inputs of this phi.
861 for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
862 PN.addIncoming(InValPhi->getIncomingValue(i),
863 InValPhi->getIncomingBlock(i));
864 } else {
865 // Otherwise, add one instance of the dominating value for each edge that
866 // we will be adding.
867 if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
868 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
869 PN.addIncoming(InVal, BBPN->getIncomingBlock(i));
870 } else {
871 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
872 PN.addIncoming(InVal, *PI);
873 }
874 }
875 }
876
877 // The PHIs are now updated, change everything that refers to BB to use
878 // DestBB and remove BB.
879 BB->replaceAllUsesWith(DestBB);
880 BB->eraseFromParent();
881 ++NumBlocksElim;
882
883 LLVM_DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "AFTER:\n" << *DestBB
<< "\n\n\n"; } } while (false)
;
884}
885
886// Computes a map of base pointer relocation instructions to corresponding
887// derived pointer relocation instructions given a vector of all relocate calls
888static void computeBaseDerivedRelocateMap(
889 const SmallVectorImpl<GCRelocateInst *> &AllRelocateCalls,
890 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>>
891 &RelocateInstMap) {
892 // Collect information in two maps: one primarily for locating the base object
893 // while filling the second map; the second map is the final structure holding
894 // a mapping between Base and corresponding Derived relocate calls
895 DenseMap<std::pair<unsigned, unsigned>, GCRelocateInst *> RelocateIdxMap;
896 for (auto *ThisRelocate : AllRelocateCalls) {
897 auto K = std::make_pair(ThisRelocate->getBasePtrIndex(),
898 ThisRelocate->getDerivedPtrIndex());
899 RelocateIdxMap.insert(std::make_pair(K, ThisRelocate));
900 }
901 for (auto &Item : RelocateIdxMap) {
902 std::pair<unsigned, unsigned> Key = Item.first;
903 if (Key.first == Key.second)
904 // Base relocation: nothing to insert
905 continue;
906
907 GCRelocateInst *I = Item.second;
908 auto BaseKey = std::make_pair(Key.first, Key.first);
909
910 // We're iterating over RelocateIdxMap so we cannot modify it.
911 auto MaybeBase = RelocateIdxMap.find(BaseKey);
912 if (MaybeBase == RelocateIdxMap.end())
913 // TODO: We might want to insert a new base object relocate and gep off
914 // that, if there are enough derived object relocates.
915 continue;
916
917 RelocateInstMap[MaybeBase->second].push_back(I);
918 }
919}
920
921// Accepts a GEP and extracts the operands into a vector provided they're all
922// small integer constants
923static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
924 SmallVectorImpl<Value *> &OffsetV) {
925 for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
20
Assuming the condition is false
21
Loop condition is false. Execution continues on line 932
926 // Only accept small constant integer operands
927 auto Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
928 if (!Op || Op->getZExtValue() > 20)
929 return false;
930 }
931
932 for (unsigned i = 1; i < GEP->getNumOperands(); i++)
22
Loop condition is false. Execution continues on line 934
933 OffsetV.push_back(GEP->getOperand(i));
934 return true;
23
Returning the value 1, which participates in a condition later
935}
936
937// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
938// replace, computes a replacement, and affects it.
939static bool
940simplifyRelocatesOffABase(GCRelocateInst *RelocatedBase,
941 const SmallVectorImpl<GCRelocateInst *> &Targets) {
942 bool MadeChange = false;
943 // We must ensure the relocation of derived pointer is defined after
944 // relocation of base pointer. If we find a relocation corresponding to base
945 // defined earlier than relocation of base then we move relocation of base
946 // right before found relocation. We consider only relocation in the same
947 // basic block as relocation of base. Relocations from other basic block will
948 // be skipped by optimization and we do not care about them.
949 for (auto R = RelocatedBase->getParent()->getFirstInsertionPt();
7
Loop condition is false. Execution continues on line 958
950 &*R != RelocatedBase; ++R)
6
Assuming the condition is false
951 if (auto RI = dyn_cast<GCRelocateInst>(R))
952 if (RI->getStatepoint() == RelocatedBase->getStatepoint())
953 if (RI->getBasePtrIndex() == RelocatedBase->getBasePtrIndex()) {
954 RelocatedBase->moveBefore(RI);
955 break;
956 }
957
958 for (GCRelocateInst *ToReplace : Targets) {
8
Assuming '__begin1' is not equal to '__end1'
959 assert(ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() &&((ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex
() && "Not relocating a derived object of the original base object"
) ? static_cast<void> (0) : __assert_fail ("ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() && \"Not relocating a derived object of the original base object\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 960, __PRETTY_FUNCTION__))
9
Assuming the condition is true
10
'?' condition is true
960 "Not relocating a derived object of the original base object")((ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex
() && "Not relocating a derived object of the original base object"
) ? static_cast<void> (0) : __assert_fail ("ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() && \"Not relocating a derived object of the original base object\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 960, __PRETTY_FUNCTION__))
;
961 if (ToReplace->getBasePtrIndex() == ToReplace->getDerivedPtrIndex()) {
11
Assuming the condition is false
12
Taking false branch
962 // A duplicate relocate call. TODO: coalesce duplicates.
963 continue;
964 }
965
966 if (RelocatedBase->getParent() != ToReplace->getParent()) {
13
Assuming the condition is false
14
Taking false branch
967 // Base and derived relocates are in different basic blocks.
968 // In this case transform is only valid when base dominates derived
969 // relocate. However it would be too expensive to check dominance
970 // for each such relocate, so we skip the whole transformation.
971 continue;
972 }
973
974 Value *Base = ToReplace->getBasePtr();
15
'Base' initialized here
975 auto Derived = dyn_cast<GetElementPtrInst>(ToReplace->getDerivedPtr());
16
Assuming the object is a 'GetElementPtrInst'
976 if (!Derived
16.1
'Derived' is non-null
|| Derived->getPointerOperand() != Base)
17
Assuming pointer value is null
18
Taking false branch
977 continue;
978
979 SmallVector<Value *, 2> OffsetV;
980 if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
19
Calling 'getGEPSmallConstantIntOffsetV'
24
Returning from 'getGEPSmallConstantIntOffsetV'
25
Taking false branch
981 continue;
982
983 // Create a Builder and replace the target callsite with a gep
984 assert(RelocatedBase->getNextNode() &&((RelocatedBase->getNextNode() && "Should always have one since it's not a terminator"
) ? static_cast<void> (0) : __assert_fail ("RelocatedBase->getNextNode() && \"Should always have one since it's not a terminator\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 985, __PRETTY_FUNCTION__))
26
Assuming the condition is true
27
'?' condition is true
985 "Should always have one since it's not a terminator")((RelocatedBase->getNextNode() && "Should always have one since it's not a terminator"
) ? static_cast<void> (0) : __assert_fail ("RelocatedBase->getNextNode() && \"Should always have one since it's not a terminator\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 985, __PRETTY_FUNCTION__))
;
986
987 // Insert after RelocatedBase
988 IRBuilder<> Builder(RelocatedBase->getNextNode());
989 Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
990
991 // If gc_relocate does not match the actual type, cast it to the right type.
992 // In theory, there must be a bitcast after gc_relocate if the type does not
993 // match, and we should reuse it to get the derived pointer. But it could be
994 // cases like this:
995 // bb1:
996 // ...
997 // %g1 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
998 // br label %merge
999 //
1000 // bb2:
1001 // ...
1002 // %g2 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
1003 // br label %merge
1004 //
1005 // merge:
1006 // %p1 = phi i8 addrspace(1)* [ %g1, %bb1 ], [ %g2, %bb2 ]
1007 // %cast = bitcast i8 addrspace(1)* %p1 in to i32 addrspace(1)*
1008 //
1009 // In this case, we can not find the bitcast any more. So we insert a new bitcast
1010 // no matter there is already one or not. In this way, we can handle all cases, and
1011 // the extra bitcast should be optimized away in later passes.
1012 Value *ActualRelocatedBase = RelocatedBase;
1013 if (RelocatedBase->getType() != Base->getType()) {
28
Called C++ object pointer is null
1014 ActualRelocatedBase =
1015 Builder.CreateBitCast(RelocatedBase, Base->getType());
1016 }
1017 Value *Replacement = Builder.CreateGEP(
1018 Derived->getSourceElementType(), ActualRelocatedBase, makeArrayRef(OffsetV));
1019 Replacement->takeName(ToReplace);
1020 // If the newly generated derived pointer's type does not match the original derived
1021 // pointer's type, cast the new derived pointer to match it. Same reasoning as above.
1022 Value *ActualReplacement = Replacement;
1023 if (Replacement->getType() != ToReplace->getType()) {
1024 ActualReplacement =
1025 Builder.CreateBitCast(Replacement, ToReplace->getType());
1026 }
1027 ToReplace->replaceAllUsesWith(ActualReplacement);
1028 ToReplace->eraseFromParent();
1029
1030 MadeChange = true;
1031 }
1032 return MadeChange;
1033}
1034
1035// Turns this:
1036//
1037// %base = ...
1038// %ptr = gep %base + 15
1039// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1040// %base' = relocate(%tok, i32 4, i32 4)
1041// %ptr' = relocate(%tok, i32 4, i32 5)
1042// %val = load %ptr'
1043//
1044// into this:
1045//
1046// %base = ...
1047// %ptr = gep %base + 15
1048// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1049// %base' = gc.relocate(%tok, i32 4, i32 4)
1050// %ptr' = gep %base' + 15
1051// %val = load %ptr'
1052bool CodeGenPrepare::simplifyOffsetableRelocate(Instruction &I) {
1053 bool MadeChange = false;
1054 SmallVector<GCRelocateInst *, 2> AllRelocateCalls;
1055
1056 for (auto *U : I.users())
1057 if (GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U))
1058 // Collect all the relocate calls associated with a statepoint
1059 AllRelocateCalls.push_back(Relocate);
1060
1061 // We need at least one base pointer relocation + one derived pointer
1062 // relocation to mangle
1063 if (AllRelocateCalls.size() < 2)
1
Assuming the condition is false
2
Taking false branch
1064 return false;
1065
1066 // RelocateInstMap is a mapping from the base relocate instruction to the
1067 // corresponding derived relocate instructions
1068 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>> RelocateInstMap;
1069 computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
1070 if (RelocateInstMap.empty())
3
Assuming the condition is false
4
Taking false branch
1071 return false;
1072
1073 for (auto &Item : RelocateInstMap)
1074 // Item.first is the RelocatedBase to offset against
1075 // Item.second is the vector of Targets to replace
1076 MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
5
Calling 'simplifyRelocatesOffABase'
1077 return MadeChange;
1078}
1079
1080/// Sink the specified cast instruction into its user blocks.
1081static bool SinkCast(CastInst *CI) {
1082 BasicBlock *DefBB = CI->getParent();
1083
1084 /// InsertedCasts - Only insert a cast in each block once.
1085 DenseMap<BasicBlock*, CastInst*> InsertedCasts;
1086
1087 bool MadeChange = false;
1088 for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
1089 UI != E; ) {
1090 Use &TheUse = UI.getUse();
1091 Instruction *User = cast<Instruction>(*UI);
1092
1093 // Figure out which BB this cast is used in. For PHI's this is the
1094 // appropriate predecessor block.
1095 BasicBlock *UserBB = User->getParent();
1096 if (PHINode *PN = dyn_cast<PHINode>(User)) {
1097 UserBB = PN->getIncomingBlock(TheUse);
1098 }
1099
1100 // Preincrement use iterator so we don't invalidate it.
1101 ++UI;
1102
1103 // The first insertion point of a block containing an EH pad is after the
1104 // pad. If the pad is the user, we cannot sink the cast past the pad.
1105 if (User->isEHPad())
1106 continue;
1107
1108 // If the block selected to receive the cast is an EH pad that does not
1109 // allow non-PHI instructions before the terminator, we can't sink the
1110 // cast.
1111 if (UserBB->getTerminator()->isEHPad())
1112 continue;
1113
1114 // If this user is in the same block as the cast, don't change the cast.
1115 if (UserBB == DefBB) continue;
1116
1117 // If we have already inserted a cast into this block, use it.
1118 CastInst *&InsertedCast = InsertedCasts[UserBB];
1119
1120 if (!InsertedCast) {
1121 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1122 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1122, __PRETTY_FUNCTION__))
;
1123 InsertedCast = CastInst::Create(CI->getOpcode(), CI->getOperand(0),
1124 CI->getType(), "", &*InsertPt);
1125 InsertedCast->setDebugLoc(CI->getDebugLoc());
1126 }
1127
1128 // Replace a use of the cast with a use of the new cast.
1129 TheUse = InsertedCast;
1130 MadeChange = true;
1131 ++NumCastUses;
1132 }
1133
1134 // If we removed all uses, nuke the cast.
1135 if (CI->use_empty()) {
1136 salvageDebugInfo(*CI);
1137 CI->eraseFromParent();
1138 MadeChange = true;
1139 }
1140
1141 return MadeChange;
1142}
1143
1144/// If the specified cast instruction is a noop copy (e.g. it's casting from
1145/// one pointer type to another, i32->i8 on PPC), sink it into user blocks to
1146/// reduce the number of virtual registers that must be created and coalesced.
1147///
1148/// Return true if any changes are made.
1149static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI,
1150 const DataLayout &DL) {
1151 // Sink only "cheap" (or nop) address-space casts. This is a weaker condition
1152 // than sinking only nop casts, but is helpful on some platforms.
1153 if (auto *ASC = dyn_cast<AddrSpaceCastInst>(CI)) {
1154 if (!TLI.isFreeAddrSpaceCast(ASC->getSrcAddressSpace(),
1155 ASC->getDestAddressSpace()))
1156 return false;
1157 }
1158
1159 // If this is a noop copy,
1160 EVT SrcVT = TLI.getValueType(DL, CI->getOperand(0)->getType());
1161 EVT DstVT = TLI.getValueType(DL, CI->getType());
1162
1163 // This is an fp<->int conversion?
1164 if (SrcVT.isInteger() != DstVT.isInteger())
1165 return false;
1166
1167 // If this is an extension, it will be a zero or sign extension, which
1168 // isn't a noop.
1169 if (SrcVT.bitsLT(DstVT)) return false;
1170
1171 // If these values will be promoted, find out what they will be promoted
1172 // to. This helps us consider truncates on PPC as noop copies when they
1173 // are.
1174 if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
1175 TargetLowering::TypePromoteInteger)
1176 SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
1177 if (TLI.getTypeAction(CI->getContext(), DstVT) ==
1178 TargetLowering::TypePromoteInteger)
1179 DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
1180
1181 // If, after promotion, these are the same types, this is a noop copy.
1182 if (SrcVT != DstVT)
1183 return false;
1184
1185 return SinkCast(CI);
1186}
1187
1188bool CodeGenPrepare::replaceMathCmpWithIntrinsic(BinaryOperator *BO,
1189 Value *Arg0, Value *Arg1,
1190 CmpInst *Cmp,
1191 Intrinsic::ID IID) {
1192 if (BO->getParent() != Cmp->getParent()) {
1193 // We used to use a dominator tree here to allow multi-block optimization.
1194 // But that was problematic because:
1195 // 1. It could cause a perf regression by hoisting the math op into the
1196 // critical path.
1197 // 2. It could cause a perf regression by creating a value that was live
1198 // across multiple blocks and increasing register pressure.
1199 // 3. Use of a dominator tree could cause large compile-time regression.
1200 // This is because we recompute the DT on every change in the main CGP
1201 // run-loop. The recomputing is probably unnecessary in many cases, so if
1202 // that was fixed, using a DT here would be ok.
1203 return false;
1204 }
1205
1206 // We allow matching the canonical IR (add X, C) back to (usubo X, -C).
1207 if (BO->getOpcode() == Instruction::Add &&
1208 IID == Intrinsic::usub_with_overflow) {
1209 assert(isa<Constant>(Arg1) && "Unexpected input for usubo")((isa<Constant>(Arg1) && "Unexpected input for usubo"
) ? static_cast<void> (0) : __assert_fail ("isa<Constant>(Arg1) && \"Unexpected input for usubo\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1209, __PRETTY_FUNCTION__))
;
1210 Arg1 = ConstantExpr::getNeg(cast<Constant>(Arg1));
1211 }
1212
1213 // Insert at the first instruction of the pair.
1214 Instruction *InsertPt = nullptr;
1215 for (Instruction &Iter : *Cmp->getParent()) {
1216 // If BO is an XOR, it is not guaranteed that it comes after both inputs to
1217 // the overflow intrinsic are defined.
1218 if ((BO->getOpcode() != Instruction::Xor && &Iter == BO) || &Iter == Cmp) {
1219 InsertPt = &Iter;
1220 break;
1221 }
1222 }
1223 assert(InsertPt != nullptr && "Parent block did not contain cmp or binop")((InsertPt != nullptr && "Parent block did not contain cmp or binop"
) ? static_cast<void> (0) : __assert_fail ("InsertPt != nullptr && \"Parent block did not contain cmp or binop\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1223, __PRETTY_FUNCTION__))
;
1224
1225 IRBuilder<> Builder(InsertPt);
1226 Value *MathOV = Builder.CreateBinaryIntrinsic(IID, Arg0, Arg1);
1227 if (BO->getOpcode() != Instruction::Xor) {
1228 Value *Math = Builder.CreateExtractValue(MathOV, 0, "math");
1229 BO->replaceAllUsesWith(Math);
1230 } else
1231 assert(BO->hasOneUse() &&((BO->hasOneUse() && "Patterns with XOr should use the BO only in the compare"
) ? static_cast<void> (0) : __assert_fail ("BO->hasOneUse() && \"Patterns with XOr should use the BO only in the compare\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1232, __PRETTY_FUNCTION__))
1232 "Patterns with XOr should use the BO only in the compare")((BO->hasOneUse() && "Patterns with XOr should use the BO only in the compare"
) ? static_cast<void> (0) : __assert_fail ("BO->hasOneUse() && \"Patterns with XOr should use the BO only in the compare\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1232, __PRETTY_FUNCTION__))
;
1233 Value *OV = Builder.CreateExtractValue(MathOV, 1, "ov");
1234 Cmp->replaceAllUsesWith(OV);
1235 Cmp->eraseFromParent();
1236 BO->eraseFromParent();
1237 return true;
1238}
1239
1240/// Match special-case patterns that check for unsigned add overflow.
1241static bool matchUAddWithOverflowConstantEdgeCases(CmpInst *Cmp,
1242 BinaryOperator *&Add) {
1243 // Add = add A, 1; Cmp = icmp eq A,-1 (overflow if A is max val)
1244 // Add = add A,-1; Cmp = icmp ne A, 0 (overflow if A is non-zero)
1245 Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
1246
1247 // We are not expecting non-canonical/degenerate code. Just bail out.
1248 if (isa<Constant>(A))
1249 return false;
1250
1251 ICmpInst::Predicate Pred = Cmp->getPredicate();
1252 if (Pred == ICmpInst::ICMP_EQ && match(B, m_AllOnes()))
1253 B = ConstantInt::get(B->getType(), 1);
1254 else if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt()))
1255 B = ConstantInt::get(B->getType(), -1);
1256 else
1257 return false;
1258
1259 // Check the users of the variable operand of the compare looking for an add
1260 // with the adjusted constant.
1261 for (User *U : A->users()) {
1262 if (match(U, m_Add(m_Specific(A), m_Specific(B)))) {
1263 Add = cast<BinaryOperator>(U);
1264 return true;
1265 }
1266 }
1267 return false;
1268}
1269
1270/// Try to combine the compare into a call to the llvm.uadd.with.overflow
1271/// intrinsic. Return true if any changes were made.
1272bool CodeGenPrepare::combineToUAddWithOverflow(CmpInst *Cmp,
1273 bool &ModifiedDT) {
1274 Value *A, *B;
1275 BinaryOperator *Add;
1276 if (!match(Cmp, m_UAddWithOverflow(m_Value(A), m_Value(B), m_BinOp(Add)))) {
1277 if (!matchUAddWithOverflowConstantEdgeCases(Cmp, Add))
1278 return false;
1279 // Set A and B in case we match matchUAddWithOverflowConstantEdgeCases.
1280 A = Add->getOperand(0);
1281 B = Add->getOperand(1);
1282 }
1283
1284 if (!TLI->shouldFormOverflowOp(ISD::UADDO,
1285 TLI->getValueType(*DL, Add->getType()),
1286 Add->hasNUsesOrMore(2)))
1287 return false;
1288
1289 // We don't want to move around uses of condition values this late, so we
1290 // check if it is legal to create the call to the intrinsic in the basic
1291 // block containing the icmp.
1292 if (Add->getParent() != Cmp->getParent() && !Add->hasOneUse())
1293 return false;
1294
1295 if (!replaceMathCmpWithIntrinsic(Add, A, B, Cmp,
1296 Intrinsic::uadd_with_overflow))
1297 return false;
1298
1299 // Reset callers - do not crash by iterating over a dead instruction.
1300 ModifiedDT = true;
1301 return true;
1302}
1303
1304bool CodeGenPrepare::combineToUSubWithOverflow(CmpInst *Cmp,
1305 bool &ModifiedDT) {
1306 // We are not expecting non-canonical/degenerate code. Just bail out.
1307 Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
1308 if (isa<Constant>(A) && isa<Constant>(B))
1309 return false;
1310
1311 // Convert (A u> B) to (A u< B) to simplify pattern matching.
1312 ICmpInst::Predicate Pred = Cmp->getPredicate();
1313 if (Pred == ICmpInst::ICMP_UGT) {
1314 std::swap(A, B);
1315 Pred = ICmpInst::ICMP_ULT;
1316 }
1317 // Convert special-case: (A == 0) is the same as (A u< 1).
1318 if (Pred == ICmpInst::ICMP_EQ && match(B, m_ZeroInt())) {
1319 B = ConstantInt::get(B->getType(), 1);
1320 Pred = ICmpInst::ICMP_ULT;
1321 }
1322 // Convert special-case: (A != 0) is the same as (0 u< A).
1323 if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt())) {
1324 std::swap(A, B);
1325 Pred = ICmpInst::ICMP_ULT;
1326 }
1327 if (Pred != ICmpInst::ICMP_ULT)
1328 return false;
1329
1330 // Walk the users of a variable operand of a compare looking for a subtract or
1331 // add with that same operand. Also match the 2nd operand of the compare to
1332 // the add/sub, but that may be a negated constant operand of an add.
1333 Value *CmpVariableOperand = isa<Constant>(A) ? B : A;
1334 BinaryOperator *Sub = nullptr;
1335 for (User *U : CmpVariableOperand->users()) {
1336 // A - B, A u< B --> usubo(A, B)
1337 if (match(U, m_Sub(m_Specific(A), m_Specific(B)))) {
1338 Sub = cast<BinaryOperator>(U);
1339 break;
1340 }
1341
1342 // A + (-C), A u< C (canonicalized form of (sub A, C))
1343 const APInt *CmpC, *AddC;
1344 if (match(U, m_Add(m_Specific(A), m_APInt(AddC))) &&
1345 match(B, m_APInt(CmpC)) && *AddC == -(*CmpC)) {
1346 Sub = cast<BinaryOperator>(U);
1347 break;
1348 }
1349 }
1350 if (!Sub)
1351 return false;
1352
1353 if (!TLI->shouldFormOverflowOp(ISD::USUBO,
1354 TLI->getValueType(*DL, Sub->getType()),
1355 Sub->hasNUsesOrMore(2)))
1356 return false;
1357
1358 if (!replaceMathCmpWithIntrinsic(Sub, Sub->getOperand(0), Sub->getOperand(1),
1359 Cmp, Intrinsic::usub_with_overflow))
1360 return false;
1361
1362 // Reset callers - do not crash by iterating over a dead instruction.
1363 ModifiedDT = true;
1364 return true;
1365}
1366
1367/// Sink the given CmpInst into user blocks to reduce the number of virtual
1368/// registers that must be created and coalesced. This is a clear win except on
1369/// targets with multiple condition code registers (PowerPC), where it might
1370/// lose; some adjustment may be wanted there.
1371///
1372/// Return true if any changes are made.
1373static bool sinkCmpExpression(CmpInst *Cmp, const TargetLowering &TLI) {
1374 if (TLI.hasMultipleConditionRegisters())
1375 return false;
1376
1377 // Avoid sinking soft-FP comparisons, since this can move them into a loop.
1378 if (TLI.useSoftFloat() && isa<FCmpInst>(Cmp))
1379 return false;
1380
1381 // Only insert a cmp in each block once.
1382 DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
1383
1384 bool MadeChange = false;
1385 for (Value::user_iterator UI = Cmp->user_begin(), E = Cmp->user_end();
1386 UI != E; ) {
1387 Use &TheUse = UI.getUse();
1388 Instruction *User = cast<Instruction>(*UI);
1389
1390 // Preincrement use iterator so we don't invalidate it.
1391 ++UI;
1392
1393 // Don't bother for PHI nodes.
1394 if (isa<PHINode>(User))
1395 continue;
1396
1397 // Figure out which BB this cmp is used in.
1398 BasicBlock *UserBB = User->getParent();
1399 BasicBlock *DefBB = Cmp->getParent();
1400
1401 // If this user is in the same block as the cmp, don't change the cmp.
1402 if (UserBB == DefBB) continue;
1403
1404 // If we have already inserted a cmp into this block, use it.
1405 CmpInst *&InsertedCmp = InsertedCmps[UserBB];
1406
1407 if (!InsertedCmp) {
1408 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1409 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1409, __PRETTY_FUNCTION__))
;
1410 InsertedCmp =
1411 CmpInst::Create(Cmp->getOpcode(), Cmp->getPredicate(),
1412 Cmp->getOperand(0), Cmp->getOperand(1), "",
1413 &*InsertPt);
1414 // Propagate the debug info.
1415 InsertedCmp->setDebugLoc(Cmp->getDebugLoc());
1416 }
1417
1418 // Replace a use of the cmp with a use of the new cmp.
1419 TheUse = InsertedCmp;
1420 MadeChange = true;
1421 ++NumCmpUses;
1422 }
1423
1424 // If we removed all uses, nuke the cmp.
1425 if (Cmp->use_empty()) {
1426 Cmp->eraseFromParent();
1427 MadeChange = true;
1428 }
1429
1430 return MadeChange;
1431}
1432
1433/// For pattern like:
1434///
1435/// DomCond = icmp sgt/slt CmpOp0, CmpOp1 (might not be in DomBB)
1436/// ...
1437/// DomBB:
1438/// ...
1439/// br DomCond, TrueBB, CmpBB
1440/// CmpBB: (with DomBB being the single predecessor)
1441/// ...
1442/// Cmp = icmp eq CmpOp0, CmpOp1
1443/// ...
1444///
1445/// It would use two comparison on targets that lowering of icmp sgt/slt is
1446/// different from lowering of icmp eq (PowerPC). This function try to convert
1447/// 'Cmp = icmp eq CmpOp0, CmpOp1' to ' Cmp = icmp slt/sgt CmpOp0, CmpOp1'.
1448/// After that, DomCond and Cmp can use the same comparison so reduce one
1449/// comparison.
1450///
1451/// Return true if any changes are made.
1452static bool foldICmpWithDominatingICmp(CmpInst *Cmp,
1453 const TargetLowering &TLI) {
1454 if (!EnableICMP_EQToICMP_ST && TLI.isEqualityCmpFoldedWithSignedCmp())
1455 return false;
1456
1457 ICmpInst::Predicate Pred = Cmp->getPredicate();
1458 if (Pred != ICmpInst::ICMP_EQ)
1459 return false;
1460
1461 // If icmp eq has users other than BranchInst and SelectInst, converting it to
1462 // icmp slt/sgt would introduce more redundant LLVM IR.
1463 for (User *U : Cmp->users()) {
1464 if (isa<BranchInst>(U))
1465 continue;
1466 if (isa<SelectInst>(U) && cast<SelectInst>(U)->getCondition() == Cmp)
1467 continue;
1468 return false;
1469 }
1470
1471 // This is a cheap/incomplete check for dominance - just match a single
1472 // predecessor with a conditional branch.
1473 BasicBlock *CmpBB = Cmp->getParent();
1474 BasicBlock *DomBB = CmpBB->getSinglePredecessor();
1475 if (!DomBB)
1476 return false;
1477
1478 // We want to ensure that the only way control gets to the comparison of
1479 // interest is that a less/greater than comparison on the same operands is
1480 // false.
1481 Value *DomCond;
1482 BasicBlock *TrueBB, *FalseBB;
1483 if (!match(DomBB->getTerminator(), m_Br(m_Value(DomCond), TrueBB, FalseBB)))
1484 return false;
1485 if (CmpBB != FalseBB)
1486 return false;
1487
1488 Value *CmpOp0 = Cmp->getOperand(0), *CmpOp1 = Cmp->getOperand(1);
1489 ICmpInst::Predicate DomPred;
1490 if (!match(DomCond, m_ICmp(DomPred, m_Specific(CmpOp0), m_Specific(CmpOp1))))
1491 return false;
1492 if (DomPred != ICmpInst::ICMP_SGT && DomPred != ICmpInst::ICMP_SLT)
1493 return false;
1494
1495 // Convert the equality comparison to the opposite of the dominating
1496 // comparison and swap the direction for all branch/select users.
1497 // We have conceptually converted:
1498 // Res = (a < b) ? <LT_RES> : (a == b) ? <EQ_RES> : <GT_RES>;
1499 // to
1500 // Res = (a < b) ? <LT_RES> : (a > b) ? <GT_RES> : <EQ_RES>;
1501 // And similarly for branches.
1502 for (User *U : Cmp->users()) {
1503 if (auto *BI = dyn_cast<BranchInst>(U)) {
1504 assert(BI->isConditional() && "Must be conditional")((BI->isConditional() && "Must be conditional") ? static_cast
<void> (0) : __assert_fail ("BI->isConditional() && \"Must be conditional\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1504, __PRETTY_FUNCTION__))
;
1505 BI->swapSuccessors();
1506 continue;
1507 }
1508 if (auto *SI = dyn_cast<SelectInst>(U)) {
1509 // Swap operands
1510 SI->swapValues();
1511 SI->swapProfMetadata();
1512 continue;
1513 }
1514 llvm_unreachable("Must be a branch or a select")::llvm::llvm_unreachable_internal("Must be a branch or a select"
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1514)
;
1515 }
1516 Cmp->setPredicate(CmpInst::getSwappedPredicate(DomPred));
1517 return true;
1518}
1519
1520bool CodeGenPrepare::optimizeCmp(CmpInst *Cmp, bool &ModifiedDT) {
1521 if (sinkCmpExpression(Cmp, *TLI))
1522 return true;
1523
1524 if (combineToUAddWithOverflow(Cmp, ModifiedDT))
1525 return true;
1526
1527 if (combineToUSubWithOverflow(Cmp, ModifiedDT))
1528 return true;
1529
1530 if (foldICmpWithDominatingICmp(Cmp, *TLI))
1531 return true;
1532
1533 return false;
1534}
1535
1536/// Duplicate and sink the given 'and' instruction into user blocks where it is
1537/// used in a compare to allow isel to generate better code for targets where
1538/// this operation can be combined.
1539///
1540/// Return true if any changes are made.
1541static bool sinkAndCmp0Expression(Instruction *AndI,
1542 const TargetLowering &TLI,
1543 SetOfInstrs &InsertedInsts) {
1544 // Double-check that we're not trying to optimize an instruction that was
1545 // already optimized by some other part of this pass.
1546 assert(!InsertedInsts.count(AndI) &&((!InsertedInsts.count(AndI) && "Attempting to optimize already optimized and instruction"
) ? static_cast<void> (0) : __assert_fail ("!InsertedInsts.count(AndI) && \"Attempting to optimize already optimized and instruction\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1547, __PRETTY_FUNCTION__))
1547 "Attempting to optimize already optimized and instruction")((!InsertedInsts.count(AndI) && "Attempting to optimize already optimized and instruction"
) ? static_cast<void> (0) : __assert_fail ("!InsertedInsts.count(AndI) && \"Attempting to optimize already optimized and instruction\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1547, __PRETTY_FUNCTION__))
;
1548 (void) InsertedInsts;
1549
1550 // Nothing to do for single use in same basic block.
1551 if (AndI->hasOneUse() &&
1552 AndI->getParent() == cast<Instruction>(*AndI->user_begin())->getParent())
1553 return false;
1554
1555 // Try to avoid cases where sinking/duplicating is likely to increase register
1556 // pressure.
1557 if (!isa<ConstantInt>(AndI->getOperand(0)) &&
1558 !isa<ConstantInt>(AndI->getOperand(1)) &&
1559 AndI->getOperand(0)->hasOneUse() && AndI->getOperand(1)->hasOneUse())
1560 return false;
1561
1562 for (auto *U : AndI->users()) {
1563 Instruction *User = cast<Instruction>(U);
1564
1565 // Only sink 'and' feeding icmp with 0.
1566 if (!isa<ICmpInst>(User))
1567 return false;
1568
1569 auto *CmpC = dyn_cast<ConstantInt>(User->getOperand(1));
1570 if (!CmpC || !CmpC->isZero())
1571 return false;
1572 }
1573
1574 if (!TLI.isMaskAndCmp0FoldingBeneficial(*AndI))
1575 return false;
1576
1577 LLVM_DEBUG(dbgs() << "found 'and' feeding only icmp 0;\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "found 'and' feeding only icmp 0;\n"
; } } while (false)
;
1578 LLVM_DEBUG(AndI->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { AndI->getParent()->dump(); } } while
(false)
;
1579
1580 // Push the 'and' into the same block as the icmp 0. There should only be
1581 // one (icmp (and, 0)) in each block, since CSE/GVN should have removed any
1582 // others, so we don't need to keep track of which BBs we insert into.
1583 for (Value::user_iterator UI = AndI->user_begin(), E = AndI->user_end();
1584 UI != E; ) {
1585 Use &TheUse = UI.getUse();
1586 Instruction *User = cast<Instruction>(*UI);
1587
1588 // Preincrement use iterator so we don't invalidate it.
1589 ++UI;
1590
1591 LLVM_DEBUG(dbgs() << "sinking 'and' use: " << *User << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "sinking 'and' use: " <<
*User << "\n"; } } while (false)
;
1592
1593 // Keep the 'and' in the same place if the use is already in the same block.
1594 Instruction *InsertPt =
1595 User->getParent() == AndI->getParent() ? AndI : User;
1596 Instruction *InsertedAnd =
1597 BinaryOperator::Create(Instruction::And, AndI->getOperand(0),
1598 AndI->getOperand(1), "", InsertPt);
1599 // Propagate the debug info.
1600 InsertedAnd->setDebugLoc(AndI->getDebugLoc());
1601
1602 // Replace a use of the 'and' with a use of the new 'and'.
1603 TheUse = InsertedAnd;
1604 ++NumAndUses;
1605 LLVM_DEBUG(User->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { User->getParent()->dump(); } } while
(false)
;
1606 }
1607
1608 // We removed all uses, nuke the and.
1609 AndI->eraseFromParent();
1610 return true;
1611}
1612
1613/// Check if the candidates could be combined with a shift instruction, which
1614/// includes:
1615/// 1. Truncate instruction
1616/// 2. And instruction and the imm is a mask of the low bits:
1617/// imm & (imm+1) == 0
1618static bool isExtractBitsCandidateUse(Instruction *User) {
1619 if (!isa<TruncInst>(User)) {
1620 if (User->getOpcode() != Instruction::And ||
1621 !isa<ConstantInt>(User->getOperand(1)))
1622 return false;
1623
1624 const APInt &Cimm = cast<ConstantInt>(User->getOperand(1))->getValue();
1625
1626 if ((Cimm & (Cimm + 1)).getBoolValue())
1627 return false;
1628 }
1629 return true;
1630}
1631
1632/// Sink both shift and truncate instruction to the use of truncate's BB.
1633static bool
1634SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI,
1635 DenseMap<BasicBlock *, BinaryOperator *> &InsertedShifts,
1636 const TargetLowering &TLI, const DataLayout &DL) {
1637 BasicBlock *UserBB = User->getParent();
1638 DenseMap<BasicBlock *, CastInst *> InsertedTruncs;
1639 auto *TruncI = cast<TruncInst>(User);
1640 bool MadeChange = false;
1641
1642 for (Value::user_iterator TruncUI = TruncI->user_begin(),
1643 TruncE = TruncI->user_end();
1644 TruncUI != TruncE;) {
1645
1646 Use &TruncTheUse = TruncUI.getUse();
1647 Instruction *TruncUser = cast<Instruction>(*TruncUI);
1648 // Preincrement use iterator so we don't invalidate it.
1649
1650 ++TruncUI;
1651
1652 int ISDOpcode = TLI.InstructionOpcodeToISD(TruncUser->getOpcode());
1653 if (!ISDOpcode)
1654 continue;
1655
1656 // If the use is actually a legal node, there will not be an
1657 // implicit truncate.
1658 // FIXME: always querying the result type is just an
1659 // approximation; some nodes' legality is determined by the
1660 // operand or other means. There's no good way to find out though.
1661 if (TLI.isOperationLegalOrCustom(
1662 ISDOpcode, TLI.getValueType(DL, TruncUser->getType(), true)))
1663 continue;
1664
1665 // Don't bother for PHI nodes.
1666 if (isa<PHINode>(TruncUser))
1667 continue;
1668
1669 BasicBlock *TruncUserBB = TruncUser->getParent();
1670
1671 if (UserBB == TruncUserBB)
1672 continue;
1673
1674 BinaryOperator *&InsertedShift = InsertedShifts[TruncUserBB];
1675 CastInst *&InsertedTrunc = InsertedTruncs[TruncUserBB];
1676
1677 if (!InsertedShift && !InsertedTrunc) {
1678 BasicBlock::iterator InsertPt = TruncUserBB->getFirstInsertionPt();
1679 assert(InsertPt != TruncUserBB->end())((InsertPt != TruncUserBB->end()) ? static_cast<void>
(0) : __assert_fail ("InsertPt != TruncUserBB->end()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1679, __PRETTY_FUNCTION__))
;
1680 // Sink the shift
1681 if (ShiftI->getOpcode() == Instruction::AShr)
1682 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1683 "", &*InsertPt);
1684 else
1685 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1686 "", &*InsertPt);
1687 InsertedShift->setDebugLoc(ShiftI->getDebugLoc());
1688
1689 // Sink the trunc
1690 BasicBlock::iterator TruncInsertPt = TruncUserBB->getFirstInsertionPt();
1691 TruncInsertPt++;
1692 assert(TruncInsertPt != TruncUserBB->end())((TruncInsertPt != TruncUserBB->end()) ? static_cast<void
> (0) : __assert_fail ("TruncInsertPt != TruncUserBB->end()"
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1692, __PRETTY_FUNCTION__))
;
1693
1694 InsertedTrunc = CastInst::Create(TruncI->getOpcode(), InsertedShift,
1695 TruncI->getType(), "", &*TruncInsertPt);
1696 InsertedTrunc->setDebugLoc(TruncI->getDebugLoc());
1697
1698 MadeChange = true;
1699
1700 TruncTheUse = InsertedTrunc;
1701 }
1702 }
1703 return MadeChange;
1704}
1705
1706/// Sink the shift *right* instruction into user blocks if the uses could
1707/// potentially be combined with this shift instruction and generate BitExtract
1708/// instruction. It will only be applied if the architecture supports BitExtract
1709/// instruction. Here is an example:
1710/// BB1:
1711/// %x.extract.shift = lshr i64 %arg1, 32
1712/// BB2:
1713/// %x.extract.trunc = trunc i64 %x.extract.shift to i16
1714/// ==>
1715///
1716/// BB2:
1717/// %x.extract.shift.1 = lshr i64 %arg1, 32
1718/// %x.extract.trunc = trunc i64 %x.extract.shift.1 to i16
1719///
1720/// CodeGen will recognize the pattern in BB2 and generate BitExtract
1721/// instruction.
1722/// Return true if any changes are made.
1723static bool OptimizeExtractBits(BinaryOperator *ShiftI, ConstantInt *CI,
1724 const TargetLowering &TLI,
1725 const DataLayout &DL) {
1726 BasicBlock *DefBB = ShiftI->getParent();
1727
1728 /// Only insert instructions in each block once.
1729 DenseMap<BasicBlock *, BinaryOperator *> InsertedShifts;
1730
1731 bool shiftIsLegal = TLI.isTypeLegal(TLI.getValueType(DL, ShiftI->getType()));
1732
1733 bool MadeChange = false;
1734 for (Value::user_iterator UI = ShiftI->user_begin(), E = ShiftI->user_end();
1735 UI != E;) {
1736 Use &TheUse = UI.getUse();
1737 Instruction *User = cast<Instruction>(*UI);
1738 // Preincrement use iterator so we don't invalidate it.
1739 ++UI;
1740
1741 // Don't bother for PHI nodes.
1742 if (isa<PHINode>(User))
1743 continue;
1744
1745 if (!isExtractBitsCandidateUse(User))
1746 continue;
1747
1748 BasicBlock *UserBB = User->getParent();
1749
1750 if (UserBB == DefBB) {
1751 // If the shift and truncate instruction are in the same BB. The use of
1752 // the truncate(TruncUse) may still introduce another truncate if not
1753 // legal. In this case, we would like to sink both shift and truncate
1754 // instruction to the BB of TruncUse.
1755 // for example:
1756 // BB1:
1757 // i64 shift.result = lshr i64 opnd, imm
1758 // trunc.result = trunc shift.result to i16
1759 //
1760 // BB2:
1761 // ----> We will have an implicit truncate here if the architecture does
1762 // not have i16 compare.
1763 // cmp i16 trunc.result, opnd2
1764 //
1765 if (isa<TruncInst>(User) && shiftIsLegal
1766 // If the type of the truncate is legal, no truncate will be
1767 // introduced in other basic blocks.
1768 &&
1769 (!TLI.isTypeLegal(TLI.getValueType(DL, User->getType()))))
1770 MadeChange =
1771 SinkShiftAndTruncate(ShiftI, User, CI, InsertedShifts, TLI, DL);
1772
1773 continue;
1774 }
1775 // If we have already inserted a shift into this block, use it.
1776 BinaryOperator *&InsertedShift = InsertedShifts[UserBB];
1777
1778 if (!InsertedShift) {
1779 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1780 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1780, __PRETTY_FUNCTION__))
;
1781
1782 if (ShiftI->getOpcode() == Instruction::AShr)
1783 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1784 "", &*InsertPt);
1785 else
1786 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1787 "", &*InsertPt);
1788 InsertedShift->setDebugLoc(ShiftI->getDebugLoc());
1789
1790 MadeChange = true;
1791 }
1792
1793 // Replace a use of the shift with a use of the new shift.
1794 TheUse = InsertedShift;
1795 }
1796
1797 // If we removed all uses, or there are none, nuke the shift.
1798 if (ShiftI->use_empty()) {
1799 salvageDebugInfo(*ShiftI);
1800 ShiftI->eraseFromParent();
1801 MadeChange = true;
1802 }
1803
1804 return MadeChange;
1805}
1806
1807/// If counting leading or trailing zeros is an expensive operation and a zero
1808/// input is defined, add a check for zero to avoid calling the intrinsic.
1809///
1810/// We want to transform:
1811/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 false)
1812///
1813/// into:
1814/// entry:
1815/// %cmpz = icmp eq i64 %A, 0
1816/// br i1 %cmpz, label %cond.end, label %cond.false
1817/// cond.false:
1818/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 true)
1819/// br label %cond.end
1820/// cond.end:
1821/// %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ]
1822///
1823/// If the transform is performed, return true and set ModifiedDT to true.
1824static bool despeculateCountZeros(IntrinsicInst *CountZeros,
1825 const TargetLowering *TLI,
1826 const DataLayout *DL,
1827 bool &ModifiedDT) {
1828 // If a zero input is undefined, it doesn't make sense to despeculate that.
1829 if (match(CountZeros->getOperand(1), m_One()))
1830 return false;
1831
1832 // If it's cheap to speculate, there's nothing to do.
1833 auto IntrinsicID = CountZeros->getIntrinsicID();
1834 if ((IntrinsicID == Intrinsic::cttz && TLI->isCheapToSpeculateCttz()) ||
1835 (IntrinsicID == Intrinsic::ctlz && TLI->isCheapToSpeculateCtlz()))
1836 return false;
1837
1838 // Only handle legal scalar cases. Anything else requires too much work.
1839 Type *Ty = CountZeros->getType();
1840 unsigned SizeInBits = Ty->getPrimitiveSizeInBits();
1841 if (Ty->isVectorTy() || SizeInBits > DL->getLargestLegalIntTypeSizeInBits())
1842 return false;
1843
1844 // The intrinsic will be sunk behind a compare against zero and branch.
1845 BasicBlock *StartBlock = CountZeros->getParent();
1846 BasicBlock *CallBlock = StartBlock->splitBasicBlock(CountZeros, "cond.false");
1847
1848 // Create another block after the count zero intrinsic. A PHI will be added
1849 // in this block to select the result of the intrinsic or the bit-width
1850 // constant if the input to the intrinsic is zero.
1851 BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(CountZeros));
1852 BasicBlock *EndBlock = CallBlock->splitBasicBlock(SplitPt, "cond.end");
1853
1854 // Set up a builder to create a compare, conditional branch, and PHI.
1855 IRBuilder<> Builder(CountZeros->getContext());
1856 Builder.SetInsertPoint(StartBlock->getTerminator());
1857 Builder.SetCurrentDebugLocation(CountZeros->getDebugLoc());
1858
1859 // Replace the unconditional branch that was created by the first split with
1860 // a compare against zero and a conditional branch.
1861 Value *Zero = Constant::getNullValue(Ty);
1862 Value *Cmp = Builder.CreateICmpEQ(CountZeros->getOperand(0), Zero, "cmpz");
1863 Builder.CreateCondBr(Cmp, EndBlock, CallBlock);
1864 StartBlock->getTerminator()->eraseFromParent();
1865
1866 // Create a PHI in the end block to select either the output of the intrinsic
1867 // or the bit width of the operand.
1868 Builder.SetInsertPoint(&EndBlock->front());
1869 PHINode *PN = Builder.CreatePHI(Ty, 2, "ctz");
1870 CountZeros->replaceAllUsesWith(PN);
1871 Value *BitWidth = Builder.getInt(APInt(SizeInBits, SizeInBits));
1872 PN->addIncoming(BitWidth, StartBlock);
1873 PN->addIncoming(CountZeros, CallBlock);
1874
1875 // We are explicitly handling the zero case, so we can set the intrinsic's
1876 // undefined zero argument to 'true'. This will also prevent reprocessing the
1877 // intrinsic; we only despeculate when a zero input is defined.
1878 CountZeros->setArgOperand(1, Builder.getTrue());
1879 ModifiedDT = true;
1880 return true;
1881}
1882
1883bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool &ModifiedDT) {
1884 BasicBlock *BB = CI->getParent();
1885
1886 // Lower inline assembly if we can.
1887 // If we found an inline asm expession, and if the target knows how to
1888 // lower it to normal LLVM code, do so now.
1889 if (isa<InlineAsm>(CI->getCalledValue())) {
1890 if (TLI->ExpandInlineAsm(CI)) {
1891 // Avoid invalidating the iterator.
1892 CurInstIterator = BB->begin();
1893 // Avoid processing instructions out of order, which could cause
1894 // reuse before a value is defined.
1895 SunkAddrs.clear();
1896 return true;
1897 }
1898 // Sink address computing for memory operands into the block.
1899 if (optimizeInlineAsmInst(CI))
1900 return true;
1901 }
1902
1903 // Align the pointer arguments to this call if the target thinks it's a good
1904 // idea
1905 unsigned MinSize, PrefAlign;
1906 if (TLI->shouldAlignPointerArgs(CI, MinSize, PrefAlign)) {
1907 for (auto &Arg : CI->arg_operands()) {
1908 // We want to align both objects whose address is used directly and
1909 // objects whose address is used in casts and GEPs, though it only makes
1910 // sense for GEPs if the offset is a multiple of the desired alignment and
1911 // if size - offset meets the size threshold.
1912 if (!Arg->getType()->isPointerTy())
1913 continue;
1914 APInt Offset(DL->getIndexSizeInBits(
1915 cast<PointerType>(Arg->getType())->getAddressSpace()),
1916 0);
1917 Value *Val = Arg->stripAndAccumulateInBoundsConstantOffsets(*DL, Offset);
1918 uint64_t Offset2 = Offset.getLimitedValue();
1919 if ((Offset2 & (PrefAlign-1)) != 0)
1920 continue;
1921 AllocaInst *AI;
1922 if ((AI = dyn_cast<AllocaInst>(Val)) && AI->getAlignment() < PrefAlign &&
1923 DL->getTypeAllocSize(AI->getAllocatedType()) >= MinSize + Offset2)
1924 AI->setAlignment(MaybeAlign(PrefAlign));
1925 // Global variables can only be aligned if they are defined in this
1926 // object (i.e. they are uniquely initialized in this object), and
1927 // over-aligning global variables that have an explicit section is
1928 // forbidden.
1929 GlobalVariable *GV;
1930 if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() &&
1931 GV->getPointerAlignment(*DL) < PrefAlign &&
1932 DL->getTypeAllocSize(GV->getValueType()) >=
1933 MinSize + Offset2)
1934 GV->setAlignment(MaybeAlign(PrefAlign));
1935 }
1936 // If this is a memcpy (or similar) then we may be able to improve the
1937 // alignment
1938 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(CI)) {
1939 unsigned DestAlign = getKnownAlignment(MI->getDest(), *DL);
1940 if (DestAlign > MI->getDestAlignment())
1941 MI->setDestAlignment(DestAlign);
1942 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
1943 unsigned SrcAlign = getKnownAlignment(MTI->getSource(), *DL);
1944 if (SrcAlign > MTI->getSourceAlignment())
1945 MTI->setSourceAlignment(SrcAlign);
1946 }
1947 }
1948 }
1949
1950 // If we have a cold call site, try to sink addressing computation into the
1951 // cold block. This interacts with our handling for loads and stores to
1952 // ensure that we can fold all uses of a potential addressing computation
1953 // into their uses. TODO: generalize this to work over profiling data
1954 if (CI->hasFnAttr(Attribute::Cold) &&
1955 !OptSize && !llvm::shouldOptimizeForSize(BB, PSI, BFI.get()))
1956 for (auto &Arg : CI->arg_operands()) {
1957 if (!Arg->getType()->isPointerTy())
1958 continue;
1959 unsigned AS = Arg->getType()->getPointerAddressSpace();
1960 return optimizeMemoryInst(CI, Arg, Arg->getType(), AS);
1961 }
1962
1963 IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
1964 if (II) {
1965 switch (II->getIntrinsicID()) {
1966 default: break;
1967 case Intrinsic::experimental_widenable_condition: {
1968 // Give up on future widening oppurtunties so that we can fold away dead
1969 // paths and merge blocks before going into block-local instruction
1970 // selection.
1971 if (II->use_empty()) {
1972 II->eraseFromParent();
1973 return true;
1974 }
1975 Constant *RetVal = ConstantInt::getTrue(II->getContext());
1976 resetIteratorIfInvalidatedWhileCalling(BB, [&]() {
1977 replaceAndRecursivelySimplify(CI, RetVal, TLInfo, nullptr);
1978 });
1979 return true;
1980 }
1981 case Intrinsic::objectsize:
1982 llvm_unreachable("llvm.objectsize.* should have been lowered already")::llvm::llvm_unreachable_internal("llvm.objectsize.* should have been lowered already"
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1982)
;
1983 case Intrinsic::is_constant:
1984 llvm_unreachable("llvm.is.constant.* should have been lowered already")::llvm::llvm_unreachable_internal("llvm.is.constant.* should have been lowered already"
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1984)
;
1985 case Intrinsic::aarch64_stlxr:
1986 case Intrinsic::aarch64_stxr: {
1987 ZExtInst *ExtVal = dyn_cast<ZExtInst>(CI->getArgOperand(0));
1988 if (!ExtVal || !ExtVal->hasOneUse() ||
1989 ExtVal->getParent() == CI->getParent())
1990 return false;
1991 // Sink a zext feeding stlxr/stxr before it, so it can be folded into it.
1992 ExtVal->moveBefore(CI);
1993 // Mark this instruction as "inserted by CGP", so that other
1994 // optimizations don't touch it.
1995 InsertedInsts.insert(ExtVal);
1996 return true;
1997 }
1998
1999 case Intrinsic::launder_invariant_group:
2000 case Intrinsic::strip_invariant_group: {
2001 Value *ArgVal = II->getArgOperand(0);
2002 auto it = LargeOffsetGEPMap.find(II);
2003 if (it != LargeOffsetGEPMap.end()) {
2004 // Merge entries in LargeOffsetGEPMap to reflect the RAUW.
2005 // Make sure not to have to deal with iterator invalidation
2006 // after possibly adding ArgVal to LargeOffsetGEPMap.
2007 auto GEPs = std::move(it->second);
2008 LargeOffsetGEPMap[ArgVal].append(GEPs.begin(), GEPs.end());
2009 LargeOffsetGEPMap.erase(II);
2010 }
2011
2012 II->replaceAllUsesWith(ArgVal);
2013 II->eraseFromParent();
2014 return true;
2015 }
2016 case Intrinsic::cttz:
2017 case Intrinsic::ctlz:
2018 // If counting zeros is expensive, try to avoid it.
2019 return despeculateCountZeros(II, TLI, DL, ModifiedDT);
2020 case Intrinsic::dbg_value:
2021 return fixupDbgValue(II);
2022 case Intrinsic::vscale: {
2023 // If datalayout has no special restrictions on vector data layout,
2024 // replace `llvm.vscale` by an equivalent constant expression
2025 // to benefit from cheap constant propagation.
2026 Type *ScalableVectorTy =
2027 VectorType::get(Type::getInt8Ty(II->getContext()), 1, true);
2028 if (DL->getTypeAllocSize(ScalableVectorTy).getKnownMinSize() == 8) {
2029 auto Null = Constant::getNullValue(ScalableVectorTy->getPointerTo());
2030 auto One = ConstantInt::getSigned(II->getType(), 1);
2031 auto *CGep =
2032 ConstantExpr::getGetElementPtr(ScalableVectorTy, Null, One);
2033 II->replaceAllUsesWith(ConstantExpr::getPtrToInt(CGep, II->getType()));
2034 II->eraseFromParent();
2035 return true;
2036 }
2037 }
2038 }
2039
2040 SmallVector<Value *, 2> PtrOps;
2041 Type *AccessTy;
2042 if (TLI->getAddrModeArguments(II, PtrOps, AccessTy))
2043 while (!PtrOps.empty()) {
2044 Value *PtrVal = PtrOps.pop_back_val();
2045 unsigned AS = PtrVal->getType()->getPointerAddressSpace();
2046 if (optimizeMemoryInst(II, PtrVal, AccessTy, AS))
2047 return true;
2048 }
2049 }
2050
2051 // From here on out we're working with named functions.
2052 if (!CI->getCalledFunction()) return false;
2053
2054 // Lower all default uses of _chk calls. This is very similar
2055 // to what InstCombineCalls does, but here we are only lowering calls
2056 // to fortified library functions (e.g. __memcpy_chk) that have the default
2057 // "don't know" as the objectsize. Anything else should be left alone.
2058 FortifiedLibCallSimplifier Simplifier(TLInfo, true);
2059 IRBuilder<> Builder(CI);
2060 if (Value *V = Simplifier.optimizeCall(CI, Builder)) {
2061 CI->replaceAllUsesWith(V);
2062 CI->eraseFromParent();
2063 return true;
2064 }
2065
2066 return false;
2067}
2068
2069/// Look for opportunities to duplicate return instructions to the predecessor
2070/// to enable tail call optimizations. The case it is currently looking for is:
2071/// @code
2072/// bb0:
2073/// %tmp0 = tail call i32 @f0()
2074/// br label %return
2075/// bb1:
2076/// %tmp1 = tail call i32 @f1()
2077/// br label %return
2078/// bb2:
2079/// %tmp2 = tail call i32 @f2()
2080/// br label %return
2081/// return:
2082/// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
2083/// ret i32 %retval
2084/// @endcode
2085///
2086/// =>
2087///
2088/// @code
2089/// bb0:
2090/// %tmp0 = tail call i32 @f0()
2091/// ret i32 %tmp0
2092/// bb1:
2093/// %tmp1 = tail call i32 @f1()
2094/// ret i32 %tmp1
2095/// bb2:
2096/// %tmp2 = tail call i32 @f2()
2097/// ret i32 %tmp2
2098/// @endcode
2099bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT) {
2100 ReturnInst *RetI = dyn_cast<ReturnInst>(BB->getTerminator());
2101 if (!RetI)
2102 return false;
2103
2104 PHINode *PN = nullptr;
2105 ExtractValueInst *EVI = nullptr;
2106 BitCastInst *BCI = nullptr;
2107 Value *V = RetI->getReturnValue();
2108 if (V) {
2109 BCI = dyn_cast<BitCastInst>(V);
2110 if (BCI)
2111 V = BCI->getOperand(0);
2112
2113 EVI = dyn_cast<ExtractValueInst>(V);
2114 if (EVI) {
2115 V = EVI->getOperand(0);
2116 if (!std::all_of(EVI->idx_begin(), EVI->idx_end(),
2117 [](unsigned idx) { return idx == 0; }))
2118 return false;
2119 }
2120
2121 PN = dyn_cast<PHINode>(V);
2122 if (!PN)
2123 return false;
2124 }
2125
2126 if (PN && PN->getParent() != BB)
2127 return false;
2128
2129 // Make sure there are no instructions between the PHI and return, or that the
2130 // return is the first instruction in the block.
2131 if (PN) {
2132 BasicBlock::iterator BI = BB->begin();
2133 // Skip over debug and the bitcast.
2134 do {
2135 ++BI;
2136 } while (isa<DbgInfoIntrinsic>(BI) || &*BI == BCI || &*BI == EVI);
2137 if (&*BI != RetI)
2138 return false;
2139 } else {
2140 BasicBlock::iterator BI = BB->begin();
2141 while (isa<DbgInfoIntrinsic>(BI)) ++BI;
2142 if (&*BI != RetI)
2143 return false;
2144 }
2145
2146 /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
2147 /// call.
2148 const Function *F = BB->getParent();
2149 SmallVector<BasicBlock*, 4> TailCallBBs;
2150 if (PN) {
2151 for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
2152 // Look through bitcasts.
2153 Value *IncomingVal = PN->getIncomingValue(I)->stripPointerCasts();
2154 CallInst *CI = dyn_cast<CallInst>(IncomingVal);
2155 BasicBlock *PredBB = PN->getIncomingBlock(I);
2156 // Make sure the phi value is indeed produced by the tail call.
2157 if (CI && CI->hasOneUse() && CI->getParent() == PredBB &&
2158 TLI->mayBeEmittedAsTailCall(CI) &&
2159 attributesPermitTailCall(F, CI, RetI, *TLI))
2160 TailCallBBs.push_back(PredBB);
2161 }
2162 } else {
2163 SmallPtrSet<BasicBlock*, 4> VisitedBBs;
2164 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
2165 if (!VisitedBBs.insert(*PI).second)
2166 continue;
2167
2168 BasicBlock::InstListType &InstList = (*PI)->getInstList();
2169 BasicBlock::InstListType::reverse_iterator RI = InstList.rbegin();
2170 BasicBlock::InstListType::reverse_iterator RE = InstList.rend();
2171 do { ++RI; } while (RI != RE && isa<DbgInfoIntrinsic>(&*RI));
2172 if (RI == RE)
2173 continue;
2174
2175 CallInst *CI = dyn_cast<CallInst>(&*RI);
2176 if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI) &&
2177 attributesPermitTailCall(F, CI, RetI, *TLI))
2178 TailCallBBs.push_back(*PI);
2179 }
2180 }
2181
2182 bool Changed = false;
2183 for (auto const &TailCallBB : TailCallBBs) {
2184 // Make sure the call instruction is followed by an unconditional branch to
2185 // the return block.
2186 BranchInst *BI = dyn_cast<BranchInst>(TailCallBB->getTerminator());
2187 if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
2188 continue;
2189
2190 // Duplicate the return into TailCallBB.
2191 (void)FoldReturnIntoUncondBranch(RetI, BB, TailCallBB);
2192 ModifiedDT = Changed = true;
2193 ++NumRetsDup;
2194 }
2195
2196 // If we eliminated all predecessors of the block, delete the block now.
2197 if (Changed && !BB->hasAddressTaken() && pred_begin(BB) == pred_end(BB))
2198 BB->eraseFromParent();
2199
2200 return Changed;
2201}
2202
2203//===----------------------------------------------------------------------===//
2204// Memory Optimization
2205//===----------------------------------------------------------------------===//
2206
2207namespace {
2208
2209/// This is an extended version of TargetLowering::AddrMode
2210/// which holds actual Value*'s for register values.
2211struct ExtAddrMode : public TargetLowering::AddrMode {
2212 Value *BaseReg = nullptr;
2213 Value *ScaledReg = nullptr;
2214 Value *OriginalValue = nullptr;
2215 bool InBounds = true;
2216
2217 enum FieldName {
2218 NoField = 0x00,
2219 BaseRegField = 0x01,
2220 BaseGVField = 0x02,
2221 BaseOffsField = 0x04,
2222 ScaledRegField = 0x08,
2223 ScaleField = 0x10,
2224 MultipleFields = 0xff
2225 };
2226
2227
2228 ExtAddrMode() = default;
2229
2230 void print(raw_ostream &OS) const;
2231 void dump() const;
2232
2233 FieldName compare(const ExtAddrMode &other) {
2234 // First check that the types are the same on each field, as differing types
2235 // is something we can't cope with later on.
2236 if (BaseReg && other.BaseReg &&
2237 BaseReg->getType() != other.BaseReg->getType())
2238 return MultipleFields;
2239 if (BaseGV && other.BaseGV &&
2240 BaseGV->getType() != other.BaseGV->getType())
2241 return MultipleFields;
2242 if (ScaledReg && other.ScaledReg &&
2243 ScaledReg->getType() != other.ScaledReg->getType())
2244 return MultipleFields;
2245
2246 // Conservatively reject 'inbounds' mismatches.
2247 if (InBounds != other.InBounds)
2248 return MultipleFields;
2249
2250 // Check each field to see if it differs.
2251 unsigned Result = NoField;
2252 if (BaseReg != other.BaseReg)
2253 Result |= BaseRegField;
2254 if (BaseGV != other.BaseGV)
2255 Result |= BaseGVField;
2256 if (BaseOffs != other.BaseOffs)
2257 Result |= BaseOffsField;
2258 if (ScaledReg != other.ScaledReg)
2259 Result |= ScaledRegField;
2260 // Don't count 0 as being a different scale, because that actually means
2261 // unscaled (which will already be counted by having no ScaledReg).
2262 if (Scale && other.Scale && Scale != other.Scale)
2263 Result |= ScaleField;
2264
2265 if (countPopulation(Result) > 1)
2266 return MultipleFields;
2267 else
2268 return static_cast<FieldName>(Result);
2269 }
2270
2271 // An AddrMode is trivial if it involves no calculation i.e. it is just a base
2272 // with no offset.
2273 bool isTrivial() {
2274 // An AddrMode is (BaseGV + BaseReg + BaseOffs + ScaleReg * Scale) so it is
2275 // trivial if at most one of these terms is nonzero, except that BaseGV and
2276 // BaseReg both being zero actually means a null pointer value, which we
2277 // consider to be 'non-zero' here.
2278 return !BaseOffs && !Scale && !(BaseGV && BaseReg);
2279 }
2280
2281 Value *GetFieldAsValue(FieldName Field, Type *IntPtrTy) {
2282 switch (Field) {
2283 default:
2284 return nullptr;
2285 case BaseRegField:
2286 return BaseReg;
2287 case BaseGVField:
2288 return BaseGV;
2289 case ScaledRegField:
2290 return ScaledReg;
2291 case BaseOffsField:
2292 return ConstantInt::get(IntPtrTy, BaseOffs);
2293 }
2294 }
2295
2296 void SetCombinedField(FieldName Field, Value *V,
2297 const SmallVectorImpl<ExtAddrMode> &AddrModes) {
2298 switch (Field) {
2299 default:
2300 llvm_unreachable("Unhandled fields are expected to be rejected earlier")::llvm::llvm_unreachable_internal("Unhandled fields are expected to be rejected earlier"
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2300)
;
2301 break;
2302 case ExtAddrMode::BaseRegField:
2303 BaseReg = V;
2304 break;
2305 case ExtAddrMode::BaseGVField:
2306 // A combined BaseGV is an Instruction, not a GlobalValue, so it goes
2307 // in the BaseReg field.
2308 assert(BaseReg == nullptr)((BaseReg == nullptr) ? static_cast<void> (0) : __assert_fail
("BaseReg == nullptr", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2308, __PRETTY_FUNCTION__))
;
2309 BaseReg = V;
2310 BaseGV = nullptr;
2311 break;
2312 case ExtAddrMode::ScaledRegField:
2313 ScaledReg = V;
2314 // If we have a mix of scaled and unscaled addrmodes then we want scale
2315 // to be the scale and not zero.
2316 if (!Scale)
2317 for (const ExtAddrMode &AM : AddrModes)
2318 if (AM.Scale) {
2319 Scale = AM.Scale;
2320 break;
2321 }
2322 break;
2323 case ExtAddrMode::BaseOffsField:
2324 // The offset is no longer a constant, so it goes in ScaledReg with a
2325 // scale of 1.
2326 assert(ScaledReg == nullptr)((ScaledReg == nullptr) ? static_cast<void> (0) : __assert_fail
("ScaledReg == nullptr", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2326, __PRETTY_FUNCTION__))
;
2327 ScaledReg = V;
2328 Scale = 1;
2329 BaseOffs = 0;
2330 break;
2331 }
2332 }
2333};
2334
2335} // end anonymous namespace
2336
2337#ifndef NDEBUG
2338static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
2339 AM.print(OS);
2340 return OS;
2341}
2342#endif
2343
2344#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
2345void ExtAddrMode::print(raw_ostream &OS) const {
2346 bool NeedPlus = false;
2347 OS << "[";
2348 if (InBounds)
2349 OS << "inbounds ";
2350 if (BaseGV) {
2351 OS << (NeedPlus ? " + " : "")
2352 << "GV:";
2353 BaseGV->printAsOperand(OS, /*PrintType=*/false);
2354 NeedPlus = true;
2355 }
2356
2357 if (BaseOffs) {
2358 OS << (NeedPlus ? " + " : "")
2359 << BaseOffs;
2360 NeedPlus = true;
2361 }
2362
2363 if (BaseReg) {
2364 OS << (NeedPlus ? " + " : "")
2365 << "Base:";
2366 BaseReg->printAsOperand(OS, /*PrintType=*/false);
2367 NeedPlus = true;
2368 }
2369 if (Scale) {
2370 OS << (NeedPlus ? " + " : "")
2371 << Scale << "*";
2372 ScaledReg->printAsOperand(OS, /*PrintType=*/false);
2373 }
2374
2375 OS << ']';
2376}
2377
2378LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void ExtAddrMode::dump() const {
2379 print(dbgs());
2380 dbgs() << '\n';
2381}
2382#endif
2383
2384namespace {
2385
2386/// This class provides transaction based operation on the IR.
2387/// Every change made through this class is recorded in the internal state and
2388/// can be undone (rollback) until commit is called.
2389class TypePromotionTransaction {
2390 /// This represents the common interface of the individual transaction.
2391 /// Each class implements the logic for doing one specific modification on
2392 /// the IR via the TypePromotionTransaction.
2393 class TypePromotionAction {
2394 protected:
2395 /// The Instruction modified.
2396 Instruction *Inst;
2397
2398 public:
2399 /// Constructor of the action.
2400 /// The constructor performs the related action on the IR.
2401 TypePromotionAction(Instruction *Inst) : Inst(Inst) {}
2402
2403 virtual ~TypePromotionAction() = default;
2404
2405 /// Undo the modification done by this action.
2406 /// When this method is called, the IR must be in the same state as it was
2407 /// before this action was applied.
2408 /// \pre Undoing the action works if and only if the IR is in the exact same
2409 /// state as it was directly after this action was applied.
2410 virtual void undo() = 0;
2411
2412 /// Advocate every change made by this action.
2413 /// When the results on the IR of the action are to be kept, it is important
2414 /// to call this function, otherwise hidden information may be kept forever.
2415 virtual void commit() {
2416 // Nothing to be done, this action is not doing anything.
2417 }
2418 };
2419
2420 /// Utility to remember the position of an instruction.
2421 class InsertionHandler {
2422 /// Position of an instruction.
2423 /// Either an instruction:
2424 /// - Is the first in a basic block: BB is used.
2425 /// - Has a previous instruction: PrevInst is used.
2426 union {
2427 Instruction *PrevInst;
2428 BasicBlock *BB;
2429 } Point;
2430
2431 /// Remember whether or not the instruction had a previous instruction.
2432 bool HasPrevInstruction;
2433
2434 public:
2435 /// Record the position of \p Inst.
2436 InsertionHandler(Instruction *Inst) {
2437 BasicBlock::iterator It = Inst->getIterator();
2438 HasPrevInstruction = (It != (Inst->getParent()->begin()));
2439 if (HasPrevInstruction)
2440 Point.PrevInst = &*--It;
2441 else
2442 Point.BB = Inst->getParent();
2443 }
2444
2445 /// Insert \p Inst at the recorded position.
2446 void insert(Instruction *Inst) {
2447 if (HasPrevInstruction) {
2448 if (Inst->getParent())
2449 Inst->removeFromParent();
2450 Inst->insertAfter(Point.PrevInst);
2451 } else {
2452 Instruction *Position = &*Point.BB->getFirstInsertionPt();
2453 if (Inst->getParent())
2454 Inst->moveBefore(Position);
2455 else
2456 Inst->insertBefore(Position);
2457 }
2458 }
2459 };
2460
2461 /// Move an instruction before another.
2462 class InstructionMoveBefore : public TypePromotionAction {
2463 /// Original position of the instruction.
2464 InsertionHandler Position;
2465
2466 public:
2467 /// Move \p Inst before \p Before.
2468 InstructionMoveBefore(Instruction *Inst, Instruction *Before)
2469 : TypePromotionAction(Inst), Position(Inst) {
2470 LLVM_DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Beforedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: move: " << *
Inst << "\nbefore: " << *Before << "\n"; } }
while (false)
2471 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: move: " << *
Inst << "\nbefore: " << *Before << "\n"; } }
while (false)
;
2472 Inst->moveBefore(Before);
2473 }
2474
2475 /// Move the instruction back to its original position.
2476 void undo() override {
2477 LLVM_DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: moveBefore: " <<
*Inst << "\n"; } } while (false)
;
2478 Position.insert(Inst);
2479 }
2480 };
2481
2482 /// Set the operand of an instruction with a new value.
2483 class OperandSetter : public TypePromotionAction {
2484 /// Original operand of the instruction.
2485 Value *Origin;
2486
2487 /// Index of the modified instruction.
2488 unsigned Idx;
2489
2490 public:
2491 /// Set \p Idx operand of \p Inst with \p NewVal.
2492 OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
2493 : TypePromotionAction(Inst), Idx(Idx) {
2494 LLVM_DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
2495 << "for:" << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
2496 << "with:" << *NewVal << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
;
2497 Origin = Inst->getOperand(Idx);
2498 Inst->setOperand(Idx, NewVal);
2499 }
2500
2501 /// Restore the original value of the instruction.
2502 void undo() override {
2503 LLVM_DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
2504 << "for: " << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
2505 << "with: " << *Origin << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
;
2506 Inst->setOperand(Idx, Origin);
2507 }
2508 };
2509
2510 /// Hide the operands of an instruction.
2511 /// Do as if this instruction was not using any of its operands.
2512 class OperandsHider : public TypePromotionAction {
2513 /// The list of original operands.
2514 SmallVector<Value *, 4> OriginalValues;
2515
2516 public:
2517 /// Remove \p Inst from the uses of the operands of \p Inst.
2518 OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
2519 LLVM_DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: OperandsHider: " <<
*Inst << "\n"; } } while (false)
;
2520 unsigned NumOpnds = Inst->getNumOperands();
2521 OriginalValues.reserve(NumOpnds);
2522 for (unsigned It = 0; It < NumOpnds; ++It) {
2523 // Save the current operand.
2524 Value *Val = Inst->getOperand(It);
2525 OriginalValues.push_back(Val);
2526 // Set a dummy one.
2527 // We could use OperandSetter here, but that would imply an overhead
2528 // that we are not willing to pay.
2529 Inst->setOperand(It, UndefValue::get(Val->getType()));
2530 }
2531 }
2532
2533 /// Restore the original list of uses.
2534 void undo() override {
2535 LLVM_DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: OperandsHider: "
<< *Inst << "\n"; } } while (false)
;
2536 for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
2537 Inst->setOperand(It, OriginalValues[It]);
2538 }
2539 };
2540
2541 /// Build a truncate instruction.
2542 class TruncBuilder : public TypePromotionAction {
2543 Value *Val;
2544
2545 public:
2546 /// Build a truncate instruction of \p Opnd producing a \p Ty
2547 /// result.
2548 /// trunc Opnd to Ty.
2549 TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
2550 IRBuilder<> Builder(Opnd);
2551 Val = Builder.CreateTrunc(Opnd, Ty, "promoted");
2552 LLVM_DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: TruncBuilder: " <<
*Val << "\n"; } } while (false)
;
2553 }
2554
2555 /// Get the built value.
2556 Value *getBuiltValue() { return Val; }
2557
2558 /// Remove the built instruction.
2559 void undo() override {
2560 LLVM_DEBUG(dbgs() << "Undo: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: TruncBuilder: " <<
*Val << "\n"; } } while (false)
;
2561 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2562 IVal->eraseFromParent();
2563 }
2564 };
2565
2566 /// Build a sign extension instruction.
2567 class SExtBuilder : public TypePromotionAction {
2568 Value *Val;
2569
2570 public:
2571 /// Build a sign extension instruction of \p Opnd producing a \p Ty
2572 /// result.
2573 /// sext Opnd to Ty.
2574 SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2575 : TypePromotionAction(InsertPt) {
2576 IRBuilder<> Builder(InsertPt);
2577 Val = Builder.CreateSExt(Opnd, Ty, "promoted");
2578 LLVM_DEBUG(dbgs() << "Do: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: SExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2579 }
2580
2581 /// Get the built value.
2582 Value *getBuiltValue() { return Val; }
2583
2584 /// Remove the built instruction.
2585 void undo() override {
2586 LLVM_DEBUG(dbgs() << "Undo: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: SExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2587 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2588 IVal->eraseFromParent();
2589 }
2590 };
2591
2592 /// Build a zero extension instruction.
2593 class ZExtBuilder : public TypePromotionAction {
2594 Value *Val;
2595
2596 public:
2597 /// Build a zero extension instruction of \p Opnd producing a \p Ty
2598 /// result.
2599 /// zext Opnd to Ty.
2600 ZExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2601 : TypePromotionAction(InsertPt) {
2602 IRBuilder<> Builder(InsertPt);
2603 Val = Builder.CreateZExt(Opnd, Ty, "promoted");
2604 LLVM_DEBUG(dbgs() << "Do: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: ZExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2605 }
2606
2607 /// Get the built value.
2608 Value *getBuiltValue() { return Val; }
2609
2610 /// Remove the built instruction.
2611 void undo() override {
2612 LLVM_DEBUG(dbgs() << "Undo: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: ZExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2613 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2614 IVal->eraseFromParent();
2615 }
2616 };
2617
2618 /// Mutate an instruction to another type.
2619 class TypeMutator : public TypePromotionAction {
2620 /// Record the original type.
2621 Type *OrigTy;
2622
2623 public:
2624 /// Mutate the type of \p Inst into \p NewTy.
2625 TypeMutator(Instruction *Inst, Type *NewTy)
2626 : TypePromotionAction(Inst), OrigTy(Inst->getType()) {
2627 LLVM_DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
*Inst << " with " << *NewTy << "\n"; } } while
(false)
2628 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
*Inst << " with " << *NewTy << "\n"; } } while
(false)
;
2629 Inst->mutateType(NewTy);
2630 }
2631
2632 /// Mutate the instruction back to its original type.
2633 void undo() override {
2634 LLVM_DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
*Inst << " with " << *OrigTy << "\n"; } } while
(false)
2635 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
*Inst << " with " << *OrigTy << "\n"; } } while
(false)
;
2636 Inst->mutateType(OrigTy);
2637 }
2638 };
2639
2640 /// Replace the uses of an instruction by another instruction.
2641 class UsesReplacer : public TypePromotionAction {
2642 /// Helper structure to keep track of the replaced uses.
2643 struct InstructionAndIdx {
2644 /// The instruction using the instruction.
2645 Instruction *Inst;
2646
2647 /// The index where this instruction is used for Inst.
2648 unsigned Idx;
2649
2650 InstructionAndIdx(Instruction *Inst, unsigned Idx)
2651 : Inst(Inst), Idx(Idx) {}
2652 };
2653
2654 /// Keep track of the original uses (pair Instruction, Index).
2655 SmallVector<InstructionAndIdx, 4> OriginalUses;
2656 /// Keep track of the debug users.
2657 SmallVector<DbgValueInst *, 1> DbgValues;
2658
2659 using use_iterator = SmallVectorImpl<InstructionAndIdx>::iterator;
2660
2661 public:
2662 /// Replace all the use of \p Inst by \p New.
2663 UsesReplacer(Instruction *Inst, Value *New) : TypePromotionAction(Inst) {
2664 LLVM_DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *Newdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
*Inst << " with " << *New << "\n"; } } while
(false)
2665 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
*Inst << " with " << *New << "\n"; } } while
(false)
;
2666 // Record the original uses.
2667 for (Use &U : Inst->uses()) {
2668 Instruction *UserI = cast<Instruction>(U.getUser());
2669 OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo()));
2670 }
2671 // Record the debug uses separately. They are not in the instruction's
2672 // use list, but they are replaced by RAUW.
2673 findDbgValues(DbgValues, Inst);
2674
2675 // Now, we can replace the uses.
2676 Inst->replaceAllUsesWith(New);
2677 }
2678
2679 /// Reassign the original uses of Inst to Inst.
2680 void undo() override {
2681 LLVM_DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: UsersReplacer: "
<< *Inst << "\n"; } } while (false)
;
2682 for (use_iterator UseIt = OriginalUses.begin(),
2683 EndIt = OriginalUses.end();
2684 UseIt != EndIt; ++UseIt) {
2685 UseIt->Inst->setOperand(UseIt->Idx, Inst);
2686 }
2687 // RAUW has replaced all original uses with references to the new value,
2688 // including the debug uses. Since we are undoing the replacements,
2689 // the original debug uses must also be reinstated to maintain the
2690 // correctness and utility of debug value instructions.
2691 for (auto *DVI: DbgValues) {
2692 LLVMContext &Ctx = Inst->getType()->getContext();
2693 auto *MV = MetadataAsValue::get(Ctx, ValueAsMetadata::get(Inst));
2694 DVI->setOperand(0, MV);
2695 }
2696 }
2697 };
2698
2699 /// Remove an instruction from the IR.
2700 class InstructionRemover : public TypePromotionAction {
2701 /// Original position of the instruction.
2702 InsertionHandler Inserter;
2703
2704 /// Helper structure to hide all the link to the instruction. In other
2705 /// words, this helps to do as if the instruction was removed.
2706 OperandsHider Hider;
2707
2708 /// Keep track of the uses replaced, if any.
2709 UsesReplacer *Replacer = nullptr;
2710
2711 /// Keep track of instructions removed.
2712 SetOfInstrs &RemovedInsts;
2713
2714 public:
2715 /// Remove all reference of \p Inst and optionally replace all its
2716 /// uses with New.
2717 /// \p RemovedInsts Keep track of the instructions removed by this Action.
2718 /// \pre If !Inst->use_empty(), then New != nullptr
2719 InstructionRemover(Instruction *Inst, SetOfInstrs &RemovedInsts,
2720 Value *New = nullptr)
2721 : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
2722 RemovedInsts(RemovedInsts) {
2723 if (New)
2724 Replacer = new UsesReplacer(Inst, New);
2725 LLVM_DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: InstructionRemover: "
<< *Inst << "\n"; } } while (false)
;
2726 RemovedInsts.insert(Inst);
2727 /// The instructions removed here will be freed after completing
2728 /// optimizeBlock() for all blocks as we need to keep track of the
2729 /// removed instructions during promotion.
2730 Inst->removeFromParent();
2731 }
2732
2733 ~InstructionRemover() override { delete Replacer; }
2734
2735 /// Resurrect the instruction and reassign it to the proper uses if
2736 /// new value was provided when build this action.
2737 void undo() override {
2738 LLVM_DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: InstructionRemover: "
<< *Inst << "\n"; } } while (false)
;
2739 Inserter.insert(Inst);
2740 if (Replacer)
2741 Replacer->undo();
2742 Hider.undo();
2743 RemovedInsts.erase(Inst);
2744 }
2745 };
2746
2747public:
2748 /// Restoration point.
2749 /// The restoration point is a pointer to an action instead of an iterator
2750 /// because the iterator may be invalidated but not the pointer.
2751 using ConstRestorationPt = const TypePromotionAction *;
2752
2753 TypePromotionTransaction(SetOfInstrs &RemovedInsts)
2754 : RemovedInsts(RemovedInsts) {}
2755
2756 /// Advocate every changes made in that transaction.
2757 void commit();
2758
2759 /// Undo all the changes made after the given point.
2760 void rollback(ConstRestorationPt Point);
2761
2762 /// Get the current restoration point.
2763 ConstRestorationPt getRestorationPoint() const;
2764
2765 /// \name API for IR modification with state keeping to support rollback.
2766 /// @{
2767 /// Same as Instruction::setOperand.
2768 void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);
2769
2770 /// Same as Instruction::eraseFromParent.
2771 void eraseInstruction(Instruction *Inst, Value *NewVal = nullptr);
2772
2773 /// Same as Value::replaceAllUsesWith.
2774 void replaceAllUsesWith(Instruction *Inst, Value *New);
2775
2776 /// Same as Value::mutateType.
2777 void mutateType(Instruction *Inst, Type *NewTy);
2778
2779 /// Same as IRBuilder::createTrunc.
2780 Value *createTrunc(Instruction *Opnd, Type *Ty);
2781
2782 /// Same as IRBuilder::createSExt.
2783 Value *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);
2784
2785 /// Same as IRBuilder::createZExt.
2786 Value *createZExt(Instruction *Inst, Value *Opnd, Type *Ty);
2787
2788 /// Same as Instruction::moveBefore.
2789 void moveBefore(Instruction *Inst, Instruction *Before);
2790 /// @}
2791
2792private:
2793 /// The ordered list of actions made so far.
2794 SmallVector<std::unique_ptr<TypePromotionAction>, 16> Actions;
2795
2796 using CommitPt = SmallVectorImpl<std::unique_ptr<TypePromotionAction>>::iterator;
2797
2798 SetOfInstrs &RemovedInsts;
2799};
2800
2801} // end anonymous namespace
2802
2803void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
2804 Value *NewVal) {
2805 Actions.push_back(std::make_unique<TypePromotionTransaction::OperandSetter>(
2806 Inst, Idx, NewVal));
2807}
2808
2809void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
2810 Value *NewVal) {
2811 Actions.push_back(
2812 std::make_unique<TypePromotionTransaction::InstructionRemover>(
2813 Inst, RemovedInsts, NewVal));
2814}
2815
2816void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
2817 Value *New) {
2818 Actions.push_back(
2819 std::make_unique<TypePromotionTransaction::UsesReplacer>(Inst, New));
2820}
2821
2822void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
2823 Actions.push_back(
2824 std::make_unique<TypePromotionTransaction::TypeMutator>(Inst, NewTy));
2825}
2826
2827Value *TypePromotionTransaction::createTrunc(Instruction *Opnd,
2828 Type *Ty) {
2829 std::unique_ptr<TruncBuilder> Ptr(new TruncBuilder(Opnd, Ty));
2830 Value *Val = Ptr->getBuiltValue();
2831 Actions.push_back(std::move(Ptr));
2832 return Val;
2833}
2834
2835Value *TypePromotionTransaction::createSExt(Instruction *Inst,
2836 Value *Opnd, Type *Ty) {
2837 std::unique_ptr<SExtBuilder> Ptr(new SExtBuilder(Inst, Opnd, Ty));
2838 Value *Val = Ptr->getBuiltValue();
2839 Actions.push_back(std::move(Ptr));
2840 return Val;
2841}
2842
2843Value *TypePromotionTransaction::createZExt(Instruction *Inst,
2844 Value *Opnd, Type *Ty) {
2845 std::unique_ptr<ZExtBuilder> Ptr(new ZExtBuilder(Inst, Opnd, Ty));
2846 Value *Val = Ptr->getBuiltValue();
2847 Actions.push_back(std::move(Ptr));
2848 return Val;
2849}
2850
2851void TypePromotionTransaction::moveBefore(Instruction *Inst,
2852 Instruction *Before) {
2853 Actions.push_back(
2854 std::make_unique<TypePromotionTransaction::InstructionMoveBefore>(
2855 Inst, Before));
2856}
2857
2858TypePromotionTransaction::ConstRestorationPt
2859TypePromotionTransaction::getRestorationPoint() const {
2860 return !Actions.empty() ? Actions.back().get() : nullptr;
2861}
2862
2863void TypePromotionTransaction::commit() {
2864 for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt;
2865 ++It)
2866 (*It)->commit();
2867 Actions.clear();
2868}
2869
2870void TypePromotionTransaction::rollback(
2871 TypePromotionTransaction::ConstRestorationPt Point) {
2872 while (!Actions.empty() && Point != Actions.back().get()) {
2873 std::unique_ptr<TypePromotionAction> Curr = Actions.pop_back_val();
2874 Curr->undo();
2875 }
2876}
2877
2878namespace {
2879
2880/// A helper class for matching addressing modes.
2881///
2882/// This encapsulates the logic for matching the target-legal addressing modes.
2883class AddressingModeMatcher {
2884 SmallVectorImpl<Instruction*> &AddrModeInsts;
2885 const TargetLowering &TLI;
2886 const TargetRegisterInfo &TRI;
2887 const DataLayout &DL;
2888
2889 /// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
2890 /// the memory instruction that we're computing this address for.
2891 Type *AccessTy;
2892 unsigned AddrSpace;
2893 Instruction *MemoryInst;
2894
2895 /// This is the addressing mode that we're building up. This is
2896 /// part of the return value of this addressing mode matching stuff.
2897 ExtAddrMode &AddrMode;
2898
2899 /// The instructions inserted by other CodeGenPrepare optimizations.
2900 const SetOfInstrs &InsertedInsts;
2901
2902 /// A map from the instructions to their type before promotion.
2903 InstrToOrigTy &PromotedInsts;
2904
2905 /// The ongoing transaction where every action should be registered.
2906 TypePromotionTransaction &TPT;
2907
2908 // A GEP which has too large offset to be folded into the addressing mode.
2909 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP;
2910
2911 /// This is set to true when we should not do profitability checks.
2912 /// When true, IsProfitableToFoldIntoAddressingMode always returns true.
2913 bool IgnoreProfitability;
2914
2915 /// True if we are optimizing for size.
2916 bool OptSize;
2917
2918 ProfileSummaryInfo *PSI;
2919 BlockFrequencyInfo *BFI;
2920
2921 AddressingModeMatcher(
2922 SmallVectorImpl<Instruction *> &AMI, const TargetLowering &TLI,
2923 const TargetRegisterInfo &TRI, Type *AT, unsigned AS, Instruction *MI,
2924 ExtAddrMode &AM, const SetOfInstrs &InsertedInsts,
2925 InstrToOrigTy &PromotedInsts, TypePromotionTransaction &TPT,
2926 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
2927 bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI)
2928 : AddrModeInsts(AMI), TLI(TLI), TRI(TRI),
2929 DL(MI->getModule()->getDataLayout()), AccessTy(AT), AddrSpace(AS),
2930 MemoryInst(MI), AddrMode(AM), InsertedInsts(InsertedInsts),
2931 PromotedInsts(PromotedInsts), TPT(TPT), LargeOffsetGEP(LargeOffsetGEP),
2932 OptSize(OptSize), PSI(PSI), BFI(BFI) {
2933 IgnoreProfitability = false;
2934 }
2935
2936public:
2937 /// Find the maximal addressing mode that a load/store of V can fold,
2938 /// give an access type of AccessTy. This returns a list of involved
2939 /// instructions in AddrModeInsts.
2940 /// \p InsertedInsts The instructions inserted by other CodeGenPrepare
2941 /// optimizations.
2942 /// \p PromotedInsts maps the instructions to their type before promotion.
2943 /// \p The ongoing transaction where every action should be registered.
2944 static ExtAddrMode
2945 Match(Value *V, Type *AccessTy, unsigned AS, Instruction *MemoryInst,
2946 SmallVectorImpl<Instruction *> &AddrModeInsts,
2947 const TargetLowering &TLI, const TargetRegisterInfo &TRI,
2948 const SetOfInstrs &InsertedInsts, InstrToOrigTy &PromotedInsts,
2949 TypePromotionTransaction &TPT,
2950 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
2951 bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) {
2952 ExtAddrMode Result;
2953
2954 bool Success = AddressingModeMatcher(AddrModeInsts, TLI, TRI, AccessTy, AS,
2955 MemoryInst, Result, InsertedInsts,
2956 PromotedInsts, TPT, LargeOffsetGEP,
2957 OptSize, PSI, BFI)
2958 .matchAddr(V, 0);
2959 (void)Success; assert(Success && "Couldn't select *anything*?")((Success && "Couldn't select *anything*?") ? static_cast
<void> (0) : __assert_fail ("Success && \"Couldn't select *anything*?\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2959, __PRETTY_FUNCTION__))
;
2960 return Result;
2961 }
2962
2963private:
2964 bool matchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
2965 bool matchAddr(Value *Addr, unsigned Depth);
2966 bool matchOperationAddr(User *AddrInst, unsigned Opcode, unsigned Depth,
2967 bool *MovedAway = nullptr);
2968 bool isProfitableToFoldIntoAddressingMode(Instruction *I,
2969 ExtAddrMode &AMBefore,
2970 ExtAddrMode &AMAfter);
2971 bool valueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
2972 bool isPromotionProfitable(unsigned NewCost, unsigned OldCost,
2973 Value *PromotedOperand) const;
2974};
2975
2976class PhiNodeSet;
2977
2978/// An iterator for PhiNodeSet.
2979class PhiNodeSetIterator {
2980 PhiNodeSet * const Set;
2981 size_t CurrentIndex = 0;
2982
2983public:
2984 /// The constructor. Start should point to either a valid element, or be equal
2985 /// to the size of the underlying SmallVector of the PhiNodeSet.
2986 PhiNodeSetIterator(PhiNodeSet * const Set, size_t Start);
2987 PHINode * operator*() const;
2988 PhiNodeSetIterator& operator++();
2989 bool operator==(const PhiNodeSetIterator &RHS) const;
2990 bool operator!=(const PhiNodeSetIterator &RHS) const;
2991};
2992
2993/// Keeps a set of PHINodes.
2994///
2995/// This is a minimal set implementation for a specific use case:
2996/// It is very fast when there are very few elements, but also provides good
2997/// performance when there are many. It is similar to SmallPtrSet, but also
2998/// provides iteration by insertion order, which is deterministic and stable
2999/// across runs. It is also similar to SmallSetVector, but provides removing
3000/// elements in O(1) time. This is achieved by not actually removing the element
3001/// from the underlying vector, so comes at the cost of using more memory, but
3002/// that is fine, since PhiNodeSets are used as short lived objects.
3003class PhiNodeSet {
3004 friend class PhiNodeSetIterator;
3005
3006 using MapType = SmallDenseMap<PHINode *, size_t, 32>;
3007 using iterator = PhiNodeSetIterator;
3008
3009 /// Keeps the elements in the order of their insertion in the underlying
3010 /// vector. To achieve constant time removal, it never deletes any element.
3011 SmallVector<PHINode *, 32> NodeList;
3012
3013 /// Keeps the elements in the underlying set implementation. This (and not the
3014 /// NodeList defined above) is the source of truth on whether an element
3015 /// is actually in the collection.
3016 MapType NodeMap;
3017
3018 /// Points to the first valid (not deleted) element when the set is not empty
3019 /// and the value is not zero. Equals to the size of the underlying vector
3020 /// when the set is empty. When the value is 0, as in the beginning, the
3021 /// first element may or may not be valid.
3022 size_t FirstValidElement = 0;
3023
3024public:
3025 /// Inserts a new element to the collection.
3026 /// \returns true if the element is actually added, i.e. was not in the
3027 /// collection before the operation.
3028 bool insert(PHINode *Ptr) {
3029 if (NodeMap.insert(std::make_pair(Ptr, NodeList.size())).second) {
3030 NodeList.push_back(Ptr);
3031 return true;
3032 }
3033 return false;
3034 }
3035
3036 /// Removes the element from the collection.
3037 /// \returns whether the element is actually removed, i.e. was in the
3038 /// collection before the operation.
3039 bool erase(PHINode *Ptr) {
3040 auto it = NodeMap.find(Ptr);
3041 if (it != NodeMap.end()) {
3042 NodeMap.erase(Ptr);
3043 SkipRemovedElements(FirstValidElement);
3044 return true;
3045 }
3046 return false;
3047 }
3048
3049 /// Removes all elements and clears the collection.
3050 void clear() {
3051 NodeMap.clear();
3052 NodeList.clear();
3053 FirstValidElement = 0;
3054 }
3055
3056 /// \returns an iterator that will iterate the elements in the order of
3057 /// insertion.
3058 iterator begin() {
3059 if (FirstValidElement == 0)
3060 SkipRemovedElements(FirstValidElement);
3061 return PhiNodeSetIterator(this, FirstValidElement);
3062 }
3063
3064 /// \returns an iterator that points to the end of the collection.
3065 iterator end() { return PhiNodeSetIterator(this, NodeList.size()); }
3066
3067 /// Returns the number of elements in the collection.
3068 size_t size() const {
3069 return NodeMap.size();
3070 }
3071
3072 /// \returns 1 if the given element is in the collection, and 0 if otherwise.
3073 size_t count(PHINode *Ptr) const {
3074 return NodeMap.count(Ptr);
3075 }
3076
3077private:
3078 /// Updates the CurrentIndex so that it will point to a valid element.
3079 ///
3080 /// If the element of NodeList at CurrentIndex is valid, it does not
3081 /// change it. If there are no more valid elements, it updates CurrentIndex
3082 /// to point to the end of the NodeList.
3083 void SkipRemovedElements(size_t &CurrentIndex) {
3084 while (CurrentIndex < NodeList.size()) {
3085 auto it = NodeMap.find(NodeList[CurrentIndex]);
3086 // If the element has been deleted and added again later, NodeMap will
3087 // point to a different index, so CurrentIndex will still be invalid.
3088 if (it != NodeMap.end() && it->second == CurrentIndex)
3089 break;
3090 ++CurrentIndex;
3091 }
3092 }
3093};
3094
3095PhiNodeSetIterator::PhiNodeSetIterator(PhiNodeSet *const Set, size_t Start)
3096 : Set(Set), CurrentIndex(Start) {}
3097
3098PHINode * PhiNodeSetIterator::operator*() const {
3099 assert(CurrentIndex < Set->NodeList.size() &&((CurrentIndex < Set->NodeList.size() && "PhiNodeSet access out of range"
) ? static_cast<void> (0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3100, __PRETTY_FUNCTION__))
3100 "PhiNodeSet access out of range")((CurrentIndex < Set->NodeList.size() && "PhiNodeSet access out of range"
) ? static_cast<void> (0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3100, __PRETTY_FUNCTION__))
;
3101 return Set->NodeList[CurrentIndex];
3102}
3103
3104PhiNodeSetIterator& PhiNodeSetIterator::operator++() {
3105 assert(CurrentIndex < Set->NodeList.size() &&((CurrentIndex < Set->NodeList.size() && "PhiNodeSet access out of range"
) ? static_cast<void> (0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3106, __PRETTY_FUNCTION__))
3106 "PhiNodeSet access out of range")((CurrentIndex < Set->NodeList.size() && "PhiNodeSet access out of range"
) ? static_cast<void> (0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3106, __PRETTY_FUNCTION__))
;
3107 ++CurrentIndex;
3108 Set->SkipRemovedElements(CurrentIndex);
3109 return *this;
3110}
3111
3112bool PhiNodeSetIterator::operator==(const PhiNodeSetIterator &RHS) const {
3113 return CurrentIndex == RHS.CurrentIndex;
3114}
3115
3116bool PhiNodeSetIterator::operator!=(const PhiNodeSetIterator &RHS) const {
3117 return !((*this) == RHS);
3118}
3119
3120/// Keep track of simplification of Phi nodes.
3121/// Accept the set of all phi nodes and erase phi node from this set
3122/// if it is simplified.
3123class SimplificationTracker {
3124 DenseMap<Value *, Value *> Storage;
3125 const SimplifyQuery &SQ;
3126 // Tracks newly created Phi nodes. The elements are iterated by insertion
3127 // order.
3128 PhiNodeSet AllPhiNodes;
3129 // Tracks newly created Select nodes.
3130 SmallPtrSet<SelectInst *, 32> AllSelectNodes;
3131
3132public:
3133 SimplificationTracker(const SimplifyQuery &sq)
3134 : SQ(sq) {}
3135
3136 Value *Get(Value *V) {
3137 do {
3138 auto SV = Storage.find(V);
3139 if (SV == Storage.end())
3140 return V;
3141 V = SV->second;
3142 } while (true);
3143 }
3144
3145 Value *Simplify(Value *Val) {
3146 SmallVector<Value *, 32> WorkList;
3147 SmallPtrSet<Value *, 32> Visited;
3148 WorkList.push_back(Val);
3149 while (!WorkList.empty()) {
3150 auto P = WorkList.pop_back_val();
3151 if (!Visited.insert(P).second)
3152 continue;
3153 if (auto *PI = dyn_cast<Instruction>(P))
3154 if (Value *V = SimplifyInstruction(cast<Instruction>(PI), SQ)) {
3155 for (auto *U : PI->users())
3156 WorkList.push_back(cast<Value>(U));
3157 Put(PI, V);
3158 PI->replaceAllUsesWith(V);
3159 if (auto *PHI = dyn_cast<PHINode>(PI))
3160 AllPhiNodes.erase(PHI);
3161 if (auto *Select = dyn_cast<SelectInst>(PI))
3162 AllSelectNodes.erase(Select);
3163 PI->eraseFromParent();
3164 }
3165 }
3166 return Get(Val);
3167 }
3168
3169 void Put(Value *From, Value *To) {
3170 Storage.insert({ From, To });
3171 }
3172
3173 void ReplacePhi(PHINode *From, PHINode *To) {
3174 Value* OldReplacement = Get(From);
3175 while (OldReplacement != From) {
3176 From = To;
3177 To = dyn_cast<PHINode>(OldReplacement);
3178 OldReplacement = Get(From);
3179 }
3180 assert(To && Get(To) == To && "Replacement PHI node is already replaced.")((To && Get(To) == To && "Replacement PHI node is already replaced."
) ? static_cast<void> (0) : __assert_fail ("To && Get(To) == To && \"Replacement PHI node is already replaced.\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3180, __PRETTY_FUNCTION__))
;
3181 Put(From, To);
3182 From->replaceAllUsesWith(To);
3183 AllPhiNodes.erase(From);
3184 From->eraseFromParent();
3185 }
3186
3187 PhiNodeSet& newPhiNodes() { return AllPhiNodes; }
3188
3189 void insertNewPhi(PHINode *PN) { AllPhiNodes.insert(PN); }
3190
3191 void insertNewSelect(SelectInst *SI) { AllSelectNodes.insert(SI); }
3192
3193 unsigned countNewPhiNodes() const { return AllPhiNodes.size(); }
3194
3195 unsigned countNewSelectNodes() const { return AllSelectNodes.size(); }
3196
3197 void destroyNewNodes(Type *CommonType) {
3198 // For safe erasing, replace the uses with dummy value first.
3199 auto Dummy = UndefValue::get(CommonType);
3200 for (auto I : AllPhiNodes) {
3201 I->replaceAllUsesWith(Dummy);
3202 I->eraseFromParent();
3203 }
3204 AllPhiNodes.clear();
3205 for (auto I : AllSelectNodes) {
3206 I->replaceAllUsesWith(Dummy);
3207 I->eraseFromParent();
3208 }
3209 AllSelectNodes.clear();
3210 }
3211};
3212
3213/// A helper class for combining addressing modes.
3214class AddressingModeCombiner {
3215 typedef DenseMap<Value *, Value *> FoldAddrToValueMapping;
3216 typedef std::pair<PHINode *, PHINode *> PHIPair;
3217
3218private:
3219 /// The addressing modes we've collected.
3220 SmallVector<ExtAddrMode, 16> AddrModes;
3221
3222 /// The field in which the AddrModes differ, when we have more than one.
3223 ExtAddrMode::FieldName DifferentField = ExtAddrMode::NoField;
3224
3225 /// Are the AddrModes that we have all just equal to their original values?
3226 bool AllAddrModesTrivial = true;
3227
3228 /// Common Type for all different fields in addressing modes.
3229 Type *CommonType;
3230
3231 /// SimplifyQuery for simplifyInstruction utility.
3232 const SimplifyQuery &SQ;
3233
3234 /// Original Address.
3235 Value *Original;
3236
3237public:
3238 AddressingModeCombiner(const SimplifyQuery &_SQ, Value *OriginalValue)
3239 : CommonType(nullptr), SQ(_SQ), Original(OriginalValue) {}
3240
3241 /// Get the combined AddrMode
3242 const ExtAddrMode &getAddrMode() const {
3243 return AddrModes[0];
3244 }
3245
3246 /// Add a new AddrMode if it's compatible with the AddrModes we already
3247 /// have.
3248 /// \return True iff we succeeded in doing so.
3249 bool addNewAddrMode(ExtAddrMode &NewAddrMode) {
3250 // Take note of if we have any non-trivial AddrModes, as we need to detect
3251 // when all AddrModes are trivial as then we would introduce a phi or select
3252 // which just duplicates what's already there.
3253 AllAddrModesTrivial = AllAddrModesTrivial && NewAddrMode.isTrivial();
3254
3255 // If this is the first addrmode then everything is fine.
3256 if (AddrModes.empty()) {
3257 AddrModes.emplace_back(NewAddrMode);
3258 return true;
3259 }
3260
3261 // Figure out how different this is from the other address modes, which we
3262 // can do just by comparing against the first one given that we only care
3263 // about the cumulative difference.
3264 ExtAddrMode::FieldName ThisDifferentField =
3265 AddrModes[0].compare(NewAddrMode);
3266 if (DifferentField == ExtAddrMode::NoField)
3267 DifferentField = ThisDifferentField;
3268 else if (DifferentField != ThisDifferentField)
3269 DifferentField = ExtAddrMode::MultipleFields;
3270
3271 // If NewAddrMode differs in more than one dimension we cannot handle it.
3272 bool CanHandle = DifferentField != ExtAddrMode::MultipleFields;
3273
3274 // If Scale Field is different then we reject.
3275 CanHandle = CanHandle && DifferentField != ExtAddrMode::ScaleField;
3276
3277 // We also must reject the case when base offset is different and
3278 // scale reg is not null, we cannot handle this case due to merge of
3279 // different offsets will be used as ScaleReg.
3280 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseOffsField ||
3281 !NewAddrMode.ScaledReg);
3282
3283 // We also must reject the case when GV is different and BaseReg installed
3284 // due to we want to use base reg as a merge of GV values.
3285 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseGVField ||
3286 !NewAddrMode.HasBaseReg);
3287
3288 // Even if NewAddMode is the same we still need to collect it due to
3289 // original value is different. And later we will need all original values
3290 // as anchors during finding the common Phi node.
3291 if (CanHandle)
3292 AddrModes.emplace_back(NewAddrMode);
3293 else
3294 AddrModes.clear();
3295
3296 return CanHandle;
3297 }
3298
3299 /// Combine the addressing modes we've collected into a single
3300 /// addressing mode.
3301 /// \return True iff we successfully combined them or we only had one so
3302 /// didn't need to combine them anyway.
3303 bool combineAddrModes() {
3304 // If we have no AddrModes then they can't be combined.
3305 if (AddrModes.size() == 0)
3306 return false;
3307
3308 // A single AddrMode can trivially be combined.
3309 if (AddrModes.size() == 1 || DifferentField == ExtAddrMode::NoField)
3310 return true;
3311
3312 // If the AddrModes we collected are all just equal to the value they are
3313 // derived from then combining them wouldn't do anything useful.
3314 if (AllAddrModesTrivial)
3315 return false;
3316
3317 if (!addrModeCombiningAllowed())
3318 return false;
3319
3320 // Build a map between <original value, basic block where we saw it> to
3321 // value of base register.
3322 // Bail out if there is no common type.
3323 FoldAddrToValueMapping Map;
3324 if (!initializeMap(Map))
3325 return false;
3326
3327 Value *CommonValue = findCommon(Map);
3328 if (CommonValue)
3329 AddrModes[0].SetCombinedField(DifferentField, CommonValue, AddrModes);
3330 return CommonValue != nullptr;
3331 }
3332
3333private:
3334 /// Initialize Map with anchor values. For address seen
3335 /// we set the value of different field saw in this address.
3336 /// At the same time we find a common type for different field we will
3337 /// use to create new Phi/Select nodes. Keep it in CommonType field.
3338 /// Return false if there is no common type found.
3339 bool initializeMap(FoldAddrToValueMapping &Map) {
3340 // Keep track of keys where the value is null. We will need to replace it
3341 // with constant null when we know the common type.
3342 SmallVector<Value *, 2> NullValue;
3343 Type *IntPtrTy = SQ.DL.getIntPtrType(AddrModes[0].OriginalValue->getType());
3344 for (auto &AM : AddrModes) {
3345 Value *DV = AM.GetFieldAsValue(DifferentField, IntPtrTy);
3346 if (DV) {
3347 auto *Type = DV->getType();
3348 if (CommonType && CommonType != Type)
3349 return false;
3350 CommonType = Type;
3351 Map[AM.OriginalValue] = DV;
3352 } else {
3353 NullValue.push_back(AM.OriginalValue);
3354 }
3355 }
3356 assert(CommonType && "At least one non-null value must be!")((CommonType && "At least one non-null value must be!"
) ? static_cast<void> (0) : __assert_fail ("CommonType && \"At least one non-null value must be!\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3356, __PRETTY_FUNCTION__))
;
3357 for (auto *V : NullValue)
3358 Map[V] = Constant::getNullValue(CommonType);
3359 return true;
3360 }
3361
3362 /// We have mapping between value A and other value B where B was a field in
3363 /// addressing mode represented by A. Also we have an original value C
3364 /// representing an address we start with. Traversing from C through phi and
3365 /// selects we ended up with A's in a map. This utility function tries to find
3366 /// a value V which is a field in addressing mode C and traversing through phi
3367 /// nodes and selects we will end up in corresponded values B in a map.
3368 /// The utility will create a new Phi/Selects if needed.
3369 // The simple example looks as follows:
3370 // BB1:
3371 // p1 = b1 + 40
3372 // br cond BB2, BB3
3373 // BB2:
3374 // p2 = b2 + 40
3375 // br BB3
3376 // BB3:
3377 // p = phi [p1, BB1], [p2, BB2]
3378 // v = load p
3379 // Map is
3380 // p1 -> b1
3381 // p2 -> b2
3382 // Request is
3383 // p -> ?
3384 // The function tries to find or build phi [b1, BB1], [b2, BB2] in BB3.
3385 Value *findCommon(FoldAddrToValueMapping &Map) {
3386 // Tracks the simplification of newly created phi nodes. The reason we use
3387 // this mapping is because we will add new created Phi nodes in AddrToBase.
3388 // Simplification of Phi nodes is recursive, so some Phi node may
3389 // be simplified after we added it to AddrToBase. In reality this
3390 // simplification is possible only if original phi/selects were not
3391 // simplified yet.
3392 // Using this mapping we can find the current value in AddrToBase.
3393 SimplificationTracker ST(SQ);
3394
3395 // First step, DFS to create PHI nodes for all intermediate blocks.
3396 // Also fill traverse order for the second step.
3397 SmallVector<Value *, 32> TraverseOrder;
3398 InsertPlaceholders(Map, TraverseOrder, ST);
3399
3400 // Second Step, fill new nodes by merged values and simplify if possible.
3401 FillPlaceholders(Map, TraverseOrder, ST);
3402
3403 if (!AddrSinkNewSelects && ST.countNewSelectNodes() > 0) {
3404 ST.destroyNewNodes(CommonType);
3405 return nullptr;
3406 }
3407
3408 // Now we'd like to match New Phi nodes to existed ones.
3409 unsigned PhiNotMatchedCount = 0;
3410 if (!MatchPhiSet(ST, AddrSinkNewPhis, PhiNotMatchedCount)) {
3411 ST.destroyNewNodes(CommonType);
3412 return nullptr;
3413 }
3414
3415 auto *Result = ST.Get(Map.find(Original)->second);
3416 if (Result) {
3417 NumMemoryInstsPhiCreated += ST.countNewPhiNodes() + PhiNotMatchedCount;
3418 NumMemoryInstsSelectCreated += ST.countNewSelectNodes();
3419 }
3420 return Result;
3421 }
3422
3423 /// Try to match PHI node to Candidate.
3424 /// Matcher tracks the matched Phi nodes.
3425 bool MatchPhiNode(PHINode *PHI, PHINode *Candidate,
3426 SmallSetVector<PHIPair, 8> &Matcher,
3427 PhiNodeSet &PhiNodesToMatch) {
3428 SmallVector<PHIPair, 8> WorkList;
3429 Matcher.insert({ PHI, Candidate });
3430 SmallSet<PHINode *, 8> MatchedPHIs;
3431 MatchedPHIs.insert(PHI);
3432 WorkList.push_back({ PHI, Candidate });
3433 SmallSet<PHIPair, 8> Visited;
3434 while (!WorkList.empty()) {
3435 auto Item = WorkList.pop_back_val();
3436 if (!Visited.insert(Item).second)
3437 continue;
3438 // We iterate over all incoming values to Phi to compare them.
3439 // If values are different and both of them Phi and the first one is a
3440 // Phi we added (subject to match) and both of them is in the same basic
3441 // block then we can match our pair if values match. So we state that
3442 // these values match and add it to work list to verify that.
3443 for (auto B : Item.first->blocks()) {
3444 Value *FirstValue = Item.first->getIncomingValueForBlock(B);
3445 Value *SecondValue = Item.second->getIncomingValueForBlock(B);
3446 if (FirstValue == SecondValue)
3447 continue;
3448
3449 PHINode *FirstPhi = dyn_cast<PHINode>(FirstValue);
3450 PHINode *SecondPhi = dyn_cast<PHINode>(SecondValue);
3451
3452 // One of them is not Phi or
3453 // The first one is not Phi node from the set we'd like to match or
3454 // Phi nodes from different basic blocks then
3455 // we will not be able to match.
3456 if (!FirstPhi || !SecondPhi || !PhiNodesToMatch.count(FirstPhi) ||
3457 FirstPhi->getParent() != SecondPhi->getParent())
3458 return false;
3459
3460 // If we already matched them then continue.
3461 if (Matcher.count({ FirstPhi, SecondPhi }))
3462 continue;
3463 // So the values are different and does not match. So we need them to
3464 // match. (But we register no more than one match per PHI node, so that
3465 // we won't later try to replace them twice.)
3466 if (MatchedPHIs.insert(FirstPhi).second)
3467 Matcher.insert({ FirstPhi, SecondPhi });
3468 // But me must check it.
3469 WorkList.push_back({ FirstPhi, SecondPhi });
3470 }
3471 }
3472 return true;
3473 }
3474
3475 /// For the given set of PHI nodes (in the SimplificationTracker) try
3476 /// to find their equivalents.
3477 /// Returns false if this matching fails and creation of new Phi is disabled.
3478 bool MatchPhiSet(SimplificationTracker &ST, bool AllowNewPhiNodes,
3479 unsigned &PhiNotMatchedCount) {
3480 // Matched and PhiNodesToMatch iterate their elements in a deterministic
3481 // order, so the replacements (ReplacePhi) are also done in a deterministic
3482 // order.
3483 SmallSetVector<PHIPair, 8> Matched;
3484 SmallPtrSet<PHINode *, 8> WillNotMatch;
3485 PhiNodeSet &PhiNodesToMatch = ST.newPhiNodes();
3486 while (PhiNodesToMatch.size()) {
3487 PHINode *PHI = *PhiNodesToMatch.begin();
3488
3489 // Add us, if no Phi nodes in the basic block we do not match.
3490 WillNotMatch.clear();
3491 WillNotMatch.insert(PHI);
3492
3493 // Traverse all Phis until we found equivalent or fail to do that.
3494 bool IsMatched = false;
3495 for (auto &P : PHI->getParent()->phis()) {
3496 if (&P == PHI)
3497 continue;
3498 if ((IsMatched = MatchPhiNode(PHI, &P, Matched, PhiNodesToMatch)))
3499 break;
3500 // If it does not match, collect all Phi nodes from matcher.
3501 // if we end up with no match, them all these Phi nodes will not match
3502 // later.
3503 for (auto M : Matched)
3504 WillNotMatch.insert(M.first);
3505 Matched.clear();
3506 }
3507 if (IsMatched) {
3508 // Replace all matched values and erase them.
3509 for (auto MV : Matched)
3510 ST.ReplacePhi(MV.first, MV.second);
3511 Matched.clear();
3512 continue;
3513 }
3514 // If we are not allowed to create new nodes then bail out.
3515 if (!AllowNewPhiNodes)
3516 return false;
3517 // Just remove all seen values in matcher. They will not match anything.
3518 PhiNotMatchedCount += WillNotMatch.size();
3519 for (auto *P : WillNotMatch)
3520 PhiNodesToMatch.erase(P);
3521 }
3522 return true;
3523 }
3524 /// Fill the placeholders with values from predecessors and simplify them.
3525 void FillPlaceholders(FoldAddrToValueMapping &Map,
3526 SmallVectorImpl<Value *> &TraverseOrder,
3527 SimplificationTracker &ST) {
3528 while (!TraverseOrder.empty()) {
3529 Value *Current = TraverseOrder.pop_back_val();
3530 assert(Map.find(Current) != Map.end() && "No node to fill!!!")((Map.find(Current) != Map.end() && "No node to fill!!!"
) ? static_cast<void> (0) : __assert_fail ("Map.find(Current) != Map.end() && \"No node to fill!!!\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3530, __PRETTY_FUNCTION__))
;
3531 Value *V = Map[Current];
3532
3533 if (SelectInst *Select = dyn_cast<SelectInst>(V)) {
3534 // CurrentValue also must be Select.
3535 auto *CurrentSelect = cast<SelectInst>(Current);
3536 auto *TrueValue = CurrentSelect->getTrueValue();
3537 assert(Map.find(TrueValue) != Map.end() && "No True Value!")((Map.find(TrueValue) != Map.end() && "No True Value!"
) ? static_cast<void> (0) : __assert_fail ("Map.find(TrueValue) != Map.end() && \"No True Value!\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3537, __PRETTY_FUNCTION__))
;
3538 Select->setTrueValue(ST.Get(Map[TrueValue]));
3539 auto *FalseValue = CurrentSelect->getFalseValue();
3540 assert(Map.find(FalseValue) != Map.end() && "No False Value!")((Map.find(FalseValue) != Map.end() && "No False Value!"
) ? static_cast<void> (0) : __assert_fail ("Map.find(FalseValue) != Map.end() && \"No False Value!\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3540, __PRETTY_FUNCTION__))
;
3541 Select->setFalseValue(ST.Get(Map[FalseValue]));
3542 } else {
3543 // Must be a Phi node then.
3544 auto *PHI = cast<PHINode>(V);
3545 // Fill the Phi node with values from predecessors.
3546 for (auto B : predecessors(PHI->getParent())) {
3547 Value *PV = cast<PHINode>(Current)->getIncomingValueForBlock(B);
3548 assert(Map.find(PV) != Map.end() && "No predecessor Value!")((Map.find(PV) != Map.end() && "No predecessor Value!"
) ? static_cast<void> (0) : __assert_fail ("Map.find(PV) != Map.end() && \"No predecessor Value!\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3548, __PRETTY_FUNCTION__))
;
3549 PHI->addIncoming(ST.Get(Map[PV]), B);
3550 }
3551 }
3552 Map[Current] = ST.Simplify(V);
3553 }
3554 }
3555
3556 /// Starting from original value recursively iterates over def-use chain up to
3557 /// known ending values represented in a map. For each traversed phi/select
3558 /// inserts a placeholder Phi or Select.
3559 /// Reports all new created Phi/Select nodes by adding them to set.
3560 /// Also reports and order in what values have been traversed.
3561 void InsertPlaceholders(FoldAddrToValueMapping &Map,
3562 SmallVectorImpl<Value *> &TraverseOrder,
3563 SimplificationTracker &ST) {
3564 SmallVector<Value *, 32> Worklist;
3565 assert((isa<PHINode>(Original) || isa<SelectInst>(Original)) &&(((isa<PHINode>(Original) || isa<SelectInst>(Original
)) && "Address must be a Phi or Select node") ? static_cast
<void> (0) : __assert_fail ("(isa<PHINode>(Original) || isa<SelectInst>(Original)) && \"Address must be a Phi or Select node\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3566, __PRETTY_FUNCTION__))
3566 "Address must be a Phi or Select node")(((isa<PHINode>(Original) || isa<SelectInst>(Original
)) && "Address must be a Phi or Select node") ? static_cast
<void> (0) : __assert_fail ("(isa<PHINode>(Original) || isa<SelectInst>(Original)) && \"Address must be a Phi or Select node\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3566, __PRETTY_FUNCTION__))
;
3567 auto *Dummy = UndefValue::get(CommonType);
3568 Worklist.push_back(Original);
3569 while (!Worklist.empty()) {
3570 Value *Current = Worklist.pop_back_val();
3571 // if it is already visited or it is an ending value then skip it.
3572 if (Map.find(Current) != Map.end())
3573 continue;
3574 TraverseOrder.push_back(Current);
3575
3576 // CurrentValue must be a Phi node or select. All others must be covered
3577 // by anchors.
3578 if (SelectInst *CurrentSelect = dyn_cast<SelectInst>(Current)) {
3579 // Is it OK to get metadata from OrigSelect?!
3580 // Create a Select placeholder with dummy value.
3581 SelectInst *Select = SelectInst::Create(
3582 CurrentSelect->getCondition(), Dummy, Dummy,
3583 CurrentSelect->getName(), CurrentSelect, CurrentSelect);
3584 Map[Current] = Select;
3585 ST.insertNewSelect(Select);
3586 // We are interested in True and False values.
3587 Worklist.push_back(CurrentSelect->getTrueValue());
3588 Worklist.push_back(CurrentSelect->getFalseValue());
3589 } else {
3590 // It must be a Phi node then.
3591 PHINode *CurrentPhi = cast<PHINode>(Current);
3592 unsigned PredCount = CurrentPhi->getNumIncomingValues();
3593 PHINode *PHI =
3594 PHINode::Create(CommonType, PredCount, "sunk_phi", CurrentPhi);
3595 Map[Current] = PHI;
3596 ST.insertNewPhi(PHI);
3597 for (Value *P : CurrentPhi->incoming_values())
3598 Worklist.push_back(P);
3599 }
3600 }
3601 }
3602
3603 bool addrModeCombiningAllowed() {
3604 if (DisableComplexAddrModes)
3605 return false;
3606 switch (DifferentField) {
3607 default:
3608 return false;
3609 case ExtAddrMode::BaseRegField:
3610 return AddrSinkCombineBaseReg;
3611 case ExtAddrMode::BaseGVField:
3612 return AddrSinkCombineBaseGV;
3613 case ExtAddrMode::BaseOffsField:
3614 return AddrSinkCombineBaseOffs;
3615 case ExtAddrMode::ScaledRegField:
3616 return AddrSinkCombineScaledReg;
3617 }
3618 }
3619};
3620} // end anonymous namespace
3621
3622/// Try adding ScaleReg*Scale to the current addressing mode.
3623/// Return true and update AddrMode if this addr mode is legal for the target,
3624/// false if not.
3625bool AddressingModeMatcher::matchScaledValue(Value *ScaleReg, int64_t Scale,
3626 unsigned Depth) {
3627 // If Scale is 1, then this is the same as adding ScaleReg to the addressing
3628 // mode. Just process that directly.
3629 if (Scale == 1)
3630 return matchAddr(ScaleReg, Depth);
3631
3632 // If the scale is 0, it takes nothing to add this.
3633 if (Scale == 0)
3634 return true;
3635
3636 // If we already have a scale of this value, we can add to it, otherwise, we
3637 // need an available scale field.
3638 if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
3639 return false;
3640
3641 ExtAddrMode TestAddrMode = AddrMode;
3642
3643 // Add scale to turn X*4+X*3 -> X*7. This could also do things like
3644 // [A+B + A*7] -> [B+A*8].
3645 TestAddrMode.Scale += Scale;
3646 TestAddrMode.ScaledReg = ScaleReg;
3647
3648 // If the new address isn't legal, bail out.
3649 if (!TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace))
3650 return false;
3651
3652 // It was legal, so commit it.
3653 AddrMode = TestAddrMode;
3654
3655 // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
3656 // to see if ScaleReg is actually X+C. If so, we can turn this into adding
3657 // X*Scale + C*Scale to addr mode.
3658 ConstantInt *CI = nullptr; Value *AddLHS = nullptr;
3659 if (isa<Instruction>(ScaleReg) && // not a constant expr.
3660 match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI)))) {
3661 TestAddrMode.InBounds = false;
3662 TestAddrMode.ScaledReg = AddLHS;
3663 TestAddrMode.BaseOffs += CI->getSExtValue()*TestAddrMode.Scale;
3664
3665 // If this addressing mode is legal, commit it and remember that we folded
3666 // this instruction.
3667 if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace)) {
3668 AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
3669 AddrMode = TestAddrMode;
3670 return true;
3671 }
3672 }
3673
3674 // Otherwise, not (x+c)*scale, just return what we have.
3675 return true;
3676}
3677
3678/// This is a little filter, which returns true if an addressing computation
3679/// involving I might be folded into a load/store accessing it.
3680/// This doesn't need to be perfect, but needs to accept at least
3681/// the set of instructions that MatchOperationAddr can.
3682static bool MightBeFoldableInst(Instruction *I) {
3683 switch (I->getOpcode()) {
3684 case Instruction::BitCast:
3685 case Instruction::AddrSpaceCast:
3686 // Don't touch identity bitcasts.
3687 if (I->getType() == I->getOperand(0)->getType())
3688 return false;
3689 return I->getType()->isIntOrPtrTy();
3690 case Instruction::PtrToInt:
3691 // PtrToInt is always a noop, as we know that the int type is pointer sized.
3692 return true;
3693 case Instruction::IntToPtr:
3694 // We know the input is intptr_t, so this is foldable.
3695 return true;
3696 case Instruction::Add:
3697 return true;
3698 case Instruction::Mul:
3699 case Instruction::Shl:
3700 // Can only handle X*C and X << C.
3701 return isa<ConstantInt>(I->getOperand(1));
3702 case Instruction::GetElementPtr:
3703 return true;
3704 default:
3705 return false;
3706 }
3707}
3708
3709/// Check whether or not \p Val is a legal instruction for \p TLI.
3710/// \note \p Val is assumed to be the product of some type promotion.
3711/// Therefore if \p Val has an undefined state in \p TLI, this is assumed
3712/// to be legal, as the non-promoted value would have had the same state.
3713static bool isPromotedInstructionLegal(const TargetLowering &TLI,
3714 const DataLayout &DL, Value *Val) {
3715 Instruction *PromotedInst = dyn_cast<Instruction>(Val);
3716 if (!PromotedInst)
3717 return false;
3718 int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
3719 // If the ISDOpcode is undefined, it was undefined before the promotion.
3720 if (!ISDOpcode)
3721 return true;
3722 // Otherwise, check if the promoted instruction is legal or not.
3723 return TLI.isOperationLegalOrCustom(
3724 ISDOpcode, TLI.getValueType(DL, PromotedInst->getType()));
3725}
3726
3727namespace {
3728
3729/// Hepler class to perform type promotion.
3730class TypePromotionHelper {
3731 /// Utility function to add a promoted instruction \p ExtOpnd to
3732 /// \p PromotedInsts and record the type of extension we have seen.
3733 static void addPromotedInst(InstrToOrigTy &PromotedInsts,
3734 Instruction *ExtOpnd,
3735 bool IsSExt) {
3736 ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
3737 InstrToOrigTy::iterator It = PromotedInsts.find(ExtOpnd);
3738 if (It != PromotedInsts.end()) {
3739 // If the new extension is same as original, the information in
3740 // PromotedInsts[ExtOpnd] is still correct.
3741 if (It->second.getInt() == ExtTy)
3742 return;
3743
3744 // Now the new extension is different from old extension, we make
3745 // the type information invalid by setting extension type to
3746 // BothExtension.
3747 ExtTy = BothExtension;
3748 }
3749 PromotedInsts[ExtOpnd] = TypeIsSExt(ExtOpnd->getType(), ExtTy);
3750 }
3751
3752 /// Utility function to query the original type of instruction \p Opnd
3753 /// with a matched extension type. If the extension doesn't match, we
3754 /// cannot use the information we had on the original type.
3755 /// BothExtension doesn't match any extension type.
3756 static const Type *getOrigType(const InstrToOrigTy &PromotedInsts,
3757 Instruction *Opnd,
3758 bool IsSExt) {
3759 ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
3760 InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
3761 if (It != PromotedInsts.end() && It->second.getInt() == ExtTy)
3762 return It->second.getPointer();
3763 return nullptr;
3764 }
3765
3766 /// Utility function to check whether or not a sign or zero extension
3767 /// of \p Inst with \p ConsideredExtType can be moved through \p Inst by
3768 /// either using the operands of \p Inst or promoting \p Inst.
3769 /// The type of the extension is defined by \p IsSExt.
3770 /// In other words, check if:
3771 /// ext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredExtType.
3772 /// #1 Promotion applies:
3773 /// ConsideredExtType Inst (ext opnd1 to ConsideredExtType, ...).
3774 /// #2 Operand reuses:
3775 /// ext opnd1 to ConsideredExtType.
3776 /// \p PromotedInsts maps the instructions to their type before promotion.
3777 static bool canGetThrough(const Instruction *Inst, Type *ConsideredExtType,
3778 const InstrToOrigTy &PromotedInsts, bool IsSExt);
3779
3780 /// Utility function to determine if \p OpIdx should be promoted when
3781 /// promoting \p Inst.
3782 static bool shouldExtOperand(const Instruction *Inst, int OpIdx) {
3783 return !(isa<SelectInst>(Inst) && OpIdx == 0);
3784 }
3785
3786 /// Utility function to promote the operand of \p Ext when this
3787 /// operand is a promotable trunc or sext or zext.
3788 /// \p PromotedInsts maps the instructions to their type before promotion.
3789 /// \p CreatedInstsCost[out] contains the cost of all instructions
3790 /// created to promote the operand of Ext.
3791 /// Newly added extensions are inserted in \p Exts.
3792 /// Newly added truncates are inserted in \p Truncs.
3793 /// Should never be called directly.
3794 /// \return The promoted value which is used instead of Ext.
3795 static Value *promoteOperandForTruncAndAnyExt(
3796 Instruction *Ext, TypePromotionTransaction &TPT,
3797 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3798 SmallVectorImpl<Instruction *> *Exts,
3799 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI);
3800
3801 /// Utility function to promote the operand of \p Ext when this
3802 /// operand is promotable and is not a supported trunc or sext.
3803 /// \p PromotedInsts maps the instructions to their type before promotion.
3804 /// \p CreatedInstsCost[out] contains the cost of all the instructions
3805 /// created to promote the operand of Ext.
3806 /// Newly added extensions are inserted in \p Exts.
3807 /// Newly added truncates are inserted in \p Truncs.
3808 /// Should never be called directly.
3809 /// \return The promoted value which is used instead of Ext.
3810 static Value *promoteOperandForOther(Instruction *Ext,
3811 TypePromotionTransaction &TPT,
3812 InstrToOrigTy &PromotedInsts,
3813 unsigned &CreatedInstsCost,
3814 SmallVectorImpl<Instruction *> *Exts,
3815 SmallVectorImpl<Instruction *> *Truncs,
3816 const TargetLowering &TLI, bool IsSExt);
3817
3818 /// \see promoteOperandForOther.
3819 static Value *signExtendOperandForOther(
3820 Instruction *Ext, TypePromotionTransaction &TPT,
3821 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3822 SmallVectorImpl<Instruction *> *Exts,
3823 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3824 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
3825 Exts, Truncs, TLI, true);
3826 }
3827
3828 /// \see promoteOperandForOther.
3829 static Value *zeroExtendOperandForOther(
3830 Instruction *Ext, TypePromotionTransaction &TPT,
3831 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3832 SmallVectorImpl<Instruction *> *Exts,
3833 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3834 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
3835 Exts, Truncs, TLI, false);
3836 }
3837
3838public:
3839 /// Type for the utility function that promotes the operand of Ext.
3840 using Action = Value *(*)(Instruction *Ext, TypePromotionTransaction &TPT,
3841 InstrToOrigTy &PromotedInsts,
3842 unsigned &CreatedInstsCost,
3843 SmallVectorImpl<Instruction *> *Exts,
3844 SmallVectorImpl<Instruction *> *Truncs,
3845 const TargetLowering &TLI);
3846
3847 /// Given a sign/zero extend instruction \p Ext, return the appropriate
3848 /// action to promote the operand of \p Ext instead of using Ext.
3849 /// \return NULL if no promotable action is possible with the current
3850 /// sign extension.
3851 /// \p InsertedInsts keeps track of all the instructions inserted by the
3852 /// other CodeGenPrepare optimizations. This information is important
3853 /// because we do not want to promote these instructions as CodeGenPrepare
3854 /// will reinsert them later. Thus creating an infinite loop: create/remove.
3855 /// \p PromotedInsts maps the instructions to their type before promotion.
3856 static Action getAction(Instruction *Ext, const SetOfInstrs &InsertedInsts,
3857 const TargetLowering &TLI,
3858 const InstrToOrigTy &PromotedInsts);
3859};
3860
3861} // end anonymous namespace
3862
3863bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
3864 Type *ConsideredExtType,
3865 const InstrToOrigTy &PromotedInsts,
3866 bool IsSExt) {
3867 // The promotion helper does not know how to deal with vector types yet.
3868 // To be able to fix that, we would need to fix the places where we
3869 // statically extend, e.g., constants and such.
3870 if (Inst->getType()->isVectorTy())
3871 return false;
3872
3873 // We can always get through zext.
3874 if (isa<ZExtInst>(Inst))
3875 return true;
3876
3877 // sext(sext) is ok too.
3878 if (IsSExt && isa<SExtInst>(Inst))
3879 return true;
3880
3881 // We can get through binary operator, if it is legal. In other words, the
3882 // binary operator must have a nuw or nsw flag.
3883 const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst);
3884 if (BinOp && isa<OverflowingBinaryOperator>(BinOp) &&
3885 ((!IsSExt && BinOp->hasNoUnsignedWrap()) ||
3886 (IsSExt && BinOp->hasNoSignedWrap())))
3887 return true;
3888
3889 // ext(and(opnd, cst)) --> and(ext(opnd), ext(cst))
3890 if ((Inst->getOpcode() == Instruction::And ||
3891 Inst->getOpcode() == Instruction::Or))
3892 return true;
3893
3894 // ext(xor(opnd, cst)) --> xor(ext(opnd), ext(cst))
3895 if (Inst->getOpcode() == Instruction::Xor) {
3896 const ConstantInt *Cst = dyn_cast<ConstantInt>(Inst->getOperand(1));
3897 // Make sure it is not a NOT.
3898 if (Cst && !Cst->getValue().isAllOnesValue())
3899 return true;
3900 }
3901
3902 // zext(shrl(opnd, cst)) --> shrl(zext(opnd), zext(cst))
3903 // It may change a poisoned value into a regular value, like
3904 // zext i32 (shrl i8 %val, 12) --> shrl i32 (zext i8 %val), 12
3905 // poisoned value regular value
3906 // It should be OK since undef covers valid value.
3907 if (Inst->getOpcode() == Instruction::LShr && !IsSExt)
3908 return true;
3909
3910 // and(ext(shl(opnd, cst)), cst) --> and(shl(ext(opnd), ext(cst)), cst)
3911 // It may change a poisoned value into a regular value, like
3912 // zext i32 (shl i8 %val, 12) --> shl i32 (zext i8 %val), 12
3913 // poisoned value regular value
3914 // It should be OK since undef covers valid value.
3915 if (Inst->getOpcode() == Instruction::Shl && Inst->hasOneUse()) {
3916 const auto *ExtInst = cast<const Instruction>(*Inst->user_begin());
3917 if (ExtInst->hasOneUse()) {
3918 const auto *AndInst = dyn_cast<const Instruction>(*ExtInst->user_begin());
3919 if (AndInst && AndInst->getOpcode() == Instruction::And) {
3920 const auto *Cst = dyn_cast<ConstantInt>(AndInst->getOperand(1));
3921 if (Cst &&
3922 Cst->getValue().isIntN(Inst->getType()->getIntegerBitWidth()))
3923 return true;
3924 }
3925 }
3926 }
3927
3928 // Check if we can do the following simplification.
3929 // ext(trunc(opnd)) --> ext(opnd)
3930 if (!isa<TruncInst>(Inst))
3931 return false;
3932
3933 Value *OpndVal = Inst->getOperand(0);
3934 // Check if we can use this operand in the extension.
3935 // If the type is larger than the result type of the extension, we cannot.
3936 if (!OpndVal->getType()->isIntegerTy() ||
3937 OpndVal->getType()->getIntegerBitWidth() >
3938 ConsideredExtType->getIntegerBitWidth())
3939 return false;
3940
3941 // If the operand of the truncate is not an instruction, we will not have
3942 // any information on the dropped bits.
3943 // (Actually we could for constant but it is not worth the extra logic).
3944 Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
3945 if (!Opnd)
3946 return false;
3947
3948 // Check if the source of the type is narrow enough.
3949 // I.e., check that trunc just drops extended bits of the same kind of
3950 // the extension.
3951 // #1 get the type of the operand and check the kind of the extended bits.
3952 const Type *OpndType = getOrigType(PromotedInsts, Opnd, IsSExt);
3953 if (OpndType)
3954 ;
3955 else if ((IsSExt && isa<SExtInst>(Opnd)) || (!IsSExt && isa<ZExtInst>(Opnd)))
3956 OpndType = Opnd->getOperand(0)->getType();
3957 else
3958 return false;
3959
3960 // #2 check that the truncate just drops extended bits.
3961 return Inst->getType()->getIntegerBitWidth() >=
3962 OpndType->getIntegerBitWidth();
3963}
3964
3965TypePromotionHelper::Action TypePromotionHelper::getAction(
3966 Instruction *Ext, const SetOfInstrs &InsertedInsts,
3967 const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
3968 assert((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&(((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&
"Unexpected instruction type") ? static_cast<void> (0)
: __assert_fail ("(isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) && \"Unexpected instruction type\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3969, __PRETTY_FUNCTION__))
3969 "Unexpected instruction type")(((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&
"Unexpected instruction type") ? static_cast<void> (0)
: __assert_fail ("(isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) && \"Unexpected instruction type\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3969, __PRETTY_FUNCTION__))
;
3970 Instruction *ExtOpnd = dyn_cast<Instruction>(Ext->getOperand(0));
3971 Type *ExtTy = Ext->getType();
3972 bool IsSExt = isa<SExtInst>(Ext);
3973 // If the operand of the extension is not an instruction, we cannot
3974 // get through.
3975 // If it, check we can get through.
3976 if (!ExtOpnd || !canGetThrough(ExtOpnd, ExtTy, PromotedInsts, IsSExt))
3977 return nullptr;
3978
3979 // Do not promote if the operand has been added by codegenprepare.
3980 // Otherwise, it means we are undoing an optimization that is likely to be
3981 // redone, thus causing potential infinite loop.
3982 if (isa<TruncInst>(ExtOpnd) && InsertedInsts.count(ExtOpnd))
3983 return nullptr;
3984
3985 // SExt or Trunc instructions.
3986 // Return the related handler.
3987 if (isa<SExtInst>(ExtOpnd) || isa<TruncInst>(ExtOpnd) ||
3988 isa<ZExtInst>(ExtOpnd))
3989 return promoteOperandForTruncAndAnyExt;
3990
3991 // Regular instruction.
3992 // Abort early if we will have to insert non-free instructions.
3993 if (!ExtOpnd->hasOneUse() && !TLI.isTruncateFree(ExtTy, ExtOpnd->getType()))
3994 return nullptr;
3995 return IsSExt ? signExtendOperandForOther : zeroExtendOperandForOther;
3996}
3997
3998Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
3999 Instruction *SExt, TypePromotionTransaction &TPT,
4000 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4001 SmallVectorImpl<Instruction *> *Exts,
4002 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
4003 // By construction, the operand of SExt is an instruction. Otherwise we cannot
4004 // get through it and this method should not be called.
4005 Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
4006 Value *ExtVal = SExt;
4007 bool HasMergedNonFreeExt = false;
4008 if (isa<ZExtInst>(SExtOpnd)) {
4009 // Replace s|zext(zext(opnd))
4010 // => zext(opnd).
4011 HasMergedNonFreeExt = !TLI.isExtFree(SExtOpnd);
4012 Value *ZExt =
4013 TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
4014 TPT.replaceAllUsesWith(SExt, ZExt);
4015 TPT.eraseInstruction(SExt);
4016 ExtVal = ZExt;
4017 } else {
4018 // Replace z|sext(trunc(opnd)) or sext(sext(opnd))
4019 // => z|sext(opnd).
4020 TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
4021 }
4022 CreatedInstsCost = 0;
4023
4024 // Remove dead code.
4025 if (SExtOpnd->use_empty())
4026 TPT.eraseInstruction(SExtOpnd);
4027
4028 // Check if the extension is still needed.
4029 Instruction *ExtInst = dyn_cast<Instruction>(ExtVal);
4030 if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) {
4031 if (ExtInst) {
4032 if (Exts)
4033 Exts->push_back(ExtInst);
4034 CreatedInstsCost = !TLI.isExtFree(ExtInst) && !HasMergedNonFreeExt;
4035 }
4036 return ExtVal;
4037 }
4038
4039 // At this point we have: ext ty opnd to ty.
4040 // Reassign the uses of ExtInst to the opnd and remove ExtInst.
4041 Value *NextVal = ExtInst->getOperand(0);
4042 TPT.eraseInstruction(ExtInst, NextVal);
4043 return NextVal;
4044}
4045
4046Value *TypePromotionHelper::promoteOperandForOther(
4047 Instruction *Ext, TypePromotionTransaction &TPT,
4048 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4049 SmallVectorImpl<Instruction *> *Exts,
4050 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI,
4051 bool IsSExt) {
4052 // By construction, the operand of Ext is an instruction. Otherwise we cannot
4053 // get through it and this method should not be called.
4054 Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0));
4055 CreatedInstsCost = 0;
4056 if (!ExtOpnd->hasOneUse()) {
4057 // ExtOpnd will be promoted.
4058 // All its uses, but Ext, will need to use a truncated value of the
4059 // promoted version.
4060 // Create the truncate now.
4061 Value *Trunc = TPT.createTrunc(Ext, ExtOpnd->getType());
4062 if (Instruction *ITrunc = dyn_cast<Instruction>(Trunc)) {
4063 // Insert it just after the definition.
4064 ITrunc->moveAfter(ExtOpnd);
4065 if (Truncs)
4066 Truncs->push_back(ITrunc);
4067 }
4068
4069 TPT.replaceAllUsesWith(ExtOpnd, Trunc);
4070 // Restore the operand of Ext (which has been replaced by the previous call
4071 // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
4072 TPT.setOperand(Ext, 0, ExtOpnd);
4073 }
4074
4075 // Get through the Instruction:
4076 // 1. Update its type.
4077 // 2. Replace the uses of Ext by Inst.
4078 // 3. Extend each operand that needs to be extended.
4079
4080 // Remember the original type of the instruction before promotion.
4081 // This is useful to know that the high bits are sign extended bits.
4082 addPromotedInst(PromotedInsts, ExtOpnd, IsSExt);
4083 // Step #1.
4084 TPT.mutateType(ExtOpnd, Ext->getType());
4085 // Step #2.
4086 TPT.replaceAllUsesWith(Ext, ExtOpnd);
4087 // Step #3.
4088 Instruction *ExtForOpnd = Ext;
4089
4090 LLVM_DEBUG(dbgs() << "Propagate Ext to operands\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Propagate Ext to operands\n"
; } } while (false)
;
4091 for (int OpIdx = 0, EndOpIdx = ExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
4092 ++OpIdx) {
4093 LLVM_DEBUG(dbgs() << "Operand:\n" << *(ExtOpnd->getOperand(OpIdx)) << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Operand:\n" << *
(ExtOpnd->getOperand(OpIdx)) << '\n'; } } while (false
)
;
4094 if (ExtOpnd->getOperand(OpIdx)->getType() == Ext->getType() ||
4095 !shouldExtOperand(ExtOpnd, OpIdx)) {
4096 LLVM_DEBUG(dbgs() << "No need to propagate\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "No need to propagate\n"
; } } while (false)
;
4097 continue;
4098 }
4099 // Check if we can statically extend the operand.
4100 Value *Opnd = ExtOpnd->getOperand(OpIdx);
4101 if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
4102 LLVM_DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
} while (false)
;
4103 unsigned BitWidth = Ext->getType()->getIntegerBitWidth();
4104 APInt CstVal = IsSExt ? Cst->getValue().sext(BitWidth)
4105 : Cst->getValue().zext(BitWidth);
4106 TPT.setOperand(ExtOpnd, OpIdx, ConstantInt::get(Ext->getType(), CstVal));
4107 continue;
4108 }
4109 // UndefValue are typed, so we have to statically sign extend them.
4110 if (isa<UndefValue>(Opnd)) {
4111 LLVM_DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
} while (false)
;
4112 TPT.setOperand(ExtOpnd, OpIdx, UndefValue::get(Ext->getType()));
4113 continue;
4114 }
4115
4116 // Otherwise we have to explicitly sign extend the operand.
4117 // Check if Ext was reused to extend an operand.
4118 if (!ExtForOpnd) {
4119 // If yes, create a new one.
4120 LLVM_DEBUG(dbgs() << "More operands to ext\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "More operands to ext\n"
; } } while (false)
;
4121 Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
4122 : TPT.createZExt(Ext, Opnd, Ext->getType());
4123 if (!isa<Instruction>(ValForExtOpnd)) {
4124 TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd);
4125 continue;
4126 }
4127 ExtForOpnd = cast<Instruction>(ValForExtOpnd);
4128 }
4129 if (Exts)
4130 Exts->push_back(ExtForOpnd);
4131 TPT.setOperand(ExtForOpnd, 0, Opnd);
4132
4133 // Move the sign extension before the insertion point.
4134 TPT.moveBefore(ExtForOpnd, ExtOpnd);
4135 TPT.setOperand(ExtOpnd, OpIdx, ExtForOpnd);
4136 CreatedInstsCost += !TLI.isExtFree(ExtForOpnd);
4137 // If more sext are required, new instructions will have to be created.
4138 ExtForOpnd = nullptr;
4139 }
4140 if (ExtForOpnd == Ext) {
4141 LLVM_DEBUG(dbgs() << "Extension is useless now\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Extension is useless now\n"
; } } while (false)
;
4142 TPT.eraseInstruction(Ext);
4143 }
4144 return ExtOpnd;
4145}
4146
4147/// Check whether or not promoting an instruction to a wider type is profitable.
4148/// \p NewCost gives the cost of extension instructions created by the
4149/// promotion.
4150/// \p OldCost gives the cost of extension instructions before the promotion
4151/// plus the number of instructions that have been
4152/// matched in the addressing mode the promotion.
4153/// \p PromotedOperand is the value that has been promoted.
4154/// \return True if the promotion is profitable, false otherwise.
4155bool AddressingModeMatcher::isPromotionProfitable(
4156 unsigned NewCost, unsigned OldCost, Value *PromotedOperand) const {
4157 LLVM_DEBUG(dbgs() << "OldCost: " << OldCost << "\tNewCost: " << NewCostdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "OldCost: " << OldCost
<< "\tNewCost: " << NewCost << '\n'; } } while
(false)
4158 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "OldCost: " << OldCost
<< "\tNewCost: " << NewCost << '\n'; } } while
(false)
;
4159 // The cost of the new extensions is greater than the cost of the
4160 // old extension plus what we folded.
4161 // This is not profitable.
4162 if (NewCost > OldCost)
4163 return false;
4164 if (NewCost < OldCost)
4165 return true;
4166 // The promotion is neutral but it may help folding the sign extension in
4167 // loads for instance.
4168 // Check that we did not create an illegal instruction.
4169 return isPromotedInstructionLegal(TLI, DL, PromotedOperand);
4170}
4171
4172/// Given an instruction or constant expr, see if we can fold the operation
4173/// into the addressing mode. If so, update the addressing mode and return
4174/// true, otherwise return false without modifying AddrMode.
4175/// If \p MovedAway is not NULL, it contains the information of whether or
4176/// not AddrInst has to be folded into the addressing mode on success.
4177/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
4178/// because it has been moved away.
4179/// Thus AddrInst must not be added in the matched instructions.
4180/// This state can happen when AddrInst is a sext, since it may be moved away.
4181/// Therefore, AddrInst may not be valid when MovedAway is true and it must
4182/// not be referenced anymore.
4183bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
4184 unsigned Depth,
4185 bool *MovedAway) {
4186 // Avoid exponential behavior on extremely deep expression trees.
4187 if (Depth >= 5) return false;
4188
4189 // By default, all matched instructions stay in place.
4190 if (MovedAway)
4191 *MovedAway = false;
4192
4193 switch (Opcode) {
4194 case Instruction::PtrToInt:
4195 // PtrToInt is always a noop, as we know that the int type is pointer sized.
4196 return matchAddr(AddrInst->getOperand(0), Depth);
4197 case Instruction::IntToPtr: {
4198 auto AS = AddrInst->getType()->getPointerAddressSpace();
4199 auto PtrTy = MVT::getIntegerVT(DL.getPointerSizeInBits(AS));
4200 // This inttoptr is a no-op if the integer type is pointer sized.
4201 if (TLI.getValueType(DL, AddrInst->getOperand(0)->getType()) == PtrTy)
4202 return matchAddr(AddrInst->getOperand(0), Depth);
4203 return false;
4204 }
4205 case Instruction::BitCast:
4206 // BitCast is always a noop, and we can handle it as long as it is
4207 // int->int or pointer->pointer (we don't want int<->fp or something).
4208 if (AddrInst->getOperand(0)->getType()->isIntOrPtrTy() &&
4209 // Don't touch identity bitcasts. These were probably put here by LSR,
4210 // and we don't want to mess around with them. Assume it knows what it
4211 // is doing.
4212 AddrInst->getOperand(0)->getType() != AddrInst->getType())
4213 return matchAddr(AddrInst->getOperand(0), Depth);
4214 return false;
4215 case Instruction::AddrSpaceCast: {
4216 unsigned SrcAS
4217 = AddrInst->getOperand(0)->getType()->getPointerAddressSpace();
4218 unsigned DestAS = AddrInst->getType()->getPointerAddressSpace();
4219 if (TLI.isNoopAddrSpaceCast(SrcAS, DestAS))
4220 return matchAddr(AddrInst->getOperand(0), Depth);
4221 return false;
4222 }
4223 case Instruction::Add: {
4224 // Check to see if we can merge in the RHS then the LHS. If so, we win.
4225 ExtAddrMode BackupAddrMode = AddrMode;
4226 unsigned OldSize = AddrModeInsts.size();
4227 // Start a transaction at this point.
4228 // The LHS may match but not the RHS.
4229 // Therefore, we need a higher level restoration point to undo partially
4230 // matched operation.
4231 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4232 TPT.getRestorationPoint();
4233
4234 AddrMode.InBounds = false;
4235 if (matchAddr(AddrInst->getOperand(1), Depth+1) &&
4236 matchAddr(AddrInst->getOperand(0), Depth+1))
4237 return true;
4238
4239 // Restore the old addr mode info.
4240 AddrMode = BackupAddrMode;
4241 AddrModeInsts.resize(OldSize);
4242 TPT.rollback(LastKnownGood);
4243
4244 // Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
4245 if (matchAddr(AddrInst->getOperand(0), Depth+1) &&
4246 matchAddr(AddrInst->getOperand(1), Depth+1))
4247 return true;
4248
4249 // Otherwise we definitely can't merge the ADD in.
4250 AddrMode = BackupAddrMode;
4251 AddrModeInsts.resize(OldSize);
4252 TPT.rollback(LastKnownGood);
4253 break;
4254 }
4255 //case Instruction::Or:
4256 // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
4257 //break;
4258 case Instruction::Mul:
4259 case Instruction::Shl: {
4260 // Can only handle X*C and X << C.
4261 AddrMode.InBounds = false;
4262 ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
4263 if (!RHS || RHS->getBitWidth() > 64)
4264 return false;
4265 int64_t Scale = RHS->getSExtValue();
4266 if (Opcode == Instruction::Shl)
4267 Scale = 1LL << Scale;
4268
4269 return matchScaledValue(AddrInst->getOperand(0), Scale, Depth);
4270 }
4271 case Instruction::GetElementPtr: {
4272 // Scan the GEP. We check it if it contains constant offsets and at most
4273 // one variable offset.
4274 int VariableOperand = -1;
4275 unsigned VariableScale = 0;
4276
4277 int64_t ConstantOffset = 0;
4278 gep_type_iterator GTI = gep_type_begin(AddrInst);
4279 for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
4280 if (StructType *STy = GTI.getStructTypeOrNull()) {
4281 const StructLayout *SL = DL.getStructLayout(STy);
4282 unsigned Idx =
4283 cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
4284 ConstantOffset += SL->getElementOffset(Idx);
4285 } else {
4286 uint64_t TypeSize = DL.getTypeAllocSize(GTI.getIndexedType());
4287 if (ConstantInt *CI = dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
4288 const APInt &CVal = CI->getValue();
4289 if (CVal.getMinSignedBits() <= 64) {
4290 ConstantOffset += CVal.getSExtValue() * TypeSize;
4291 continue;
4292 }
4293 }
4294 if (TypeSize) { // Scales of zero don't do anything.
4295 // We only allow one variable index at the moment.
4296 if (VariableOperand != -1)
4297 return false;
4298
4299 // Remember the variable index.
4300 VariableOperand = i;
4301 VariableScale = TypeSize;
4302 }
4303 }
4304 }
4305
4306 // A common case is for the GEP to only do a constant offset. In this case,
4307 // just add it to the disp field and check validity.
4308 if (VariableOperand == -1) {
4309 AddrMode.BaseOffs += ConstantOffset;
4310 if (ConstantOffset == 0 ||
4311 TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) {
4312 // Check to see if we can fold the base pointer in too.
4313 if (matchAddr(AddrInst->getOperand(0), Depth+1)) {
4314 if (!cast<GEPOperator>(AddrInst)->isInBounds())
4315 AddrMode.InBounds = false;
4316 return true;
4317 }
4318 } else if (EnableGEPOffsetSplit && isa<GetElementPtrInst>(AddrInst) &&
4319 TLI.shouldConsiderGEPOffsetSplit() && Depth == 0 &&
4320 ConstantOffset > 0) {
4321 // Record GEPs with non-zero offsets as candidates for splitting in the
4322 // event that the offset cannot fit into the r+i addressing mode.
4323 // Simple and common case that only one GEP is used in calculating the
4324 // address for the memory access.
4325 Value *Base = AddrInst->getOperand(0);
4326 auto *BaseI = dyn_cast<Instruction>(Base);
4327 auto *GEP = cast<GetElementPtrInst>(AddrInst);
4328 if (isa<Argument>(Base) || isa<GlobalValue>(Base) ||
4329 (BaseI && !isa<CastInst>(BaseI) &&
4330 !isa<GetElementPtrInst>(BaseI))) {
4331 // Make sure the parent block allows inserting non-PHI instructions
4332 // before the terminator.
4333 BasicBlock *Parent =
4334 BaseI ? BaseI->getParent() : &GEP->getFunction()->getEntryBlock();
4335 if (!Parent->getTerminator()->isEHPad())
4336 LargeOffsetGEP = std::make_pair(GEP, ConstantOffset);
4337 }
4338 }
4339 AddrMode.BaseOffs -= ConstantOffset;
4340 return false;
4341 }
4342
4343 // Save the valid addressing mode in case we can't match.
4344 ExtAddrMode BackupAddrMode = AddrMode;
4345 unsigned OldSize = AddrModeInsts.size();
4346
4347 // See if the scale and offset amount is valid for this target.
4348 AddrMode.BaseOffs += ConstantOffset;
4349 if (!cast<GEPOperator>(AddrInst)->isInBounds())
4350 AddrMode.InBounds = false;
4351
4352 // Match the base operand of the GEP.
4353 if (!matchAddr(AddrInst->getOperand(0), Depth+1)) {
4354 // If it couldn't be matched, just stuff the value in a register.
4355 if (AddrMode.HasBaseReg) {
4356 AddrMode = BackupAddrMode;
4357 AddrModeInsts.resize(OldSize);
4358 return false;
4359 }
4360 AddrMode.HasBaseReg = true;
4361 AddrMode.BaseReg = AddrInst->getOperand(0);
4362 }
4363
4364 // Match the remaining variable portion of the GEP.
4365 if (!matchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
4366 Depth)) {
4367 // If it couldn't be matched, try stuffing the base into a register
4368 // instead of matching it, and retrying the match of the scale.
4369 AddrMode = BackupAddrMode;
4370 AddrModeInsts.resize(OldSize);
4371 if (AddrMode.HasBaseReg)
4372 return false;
4373 AddrMode.HasBaseReg = true;
4374 AddrMode.BaseReg = AddrInst->getOperand(0);
4375 AddrMode.BaseOffs += ConstantOffset;
4376 if (!matchScaledValue(AddrInst->getOperand(VariableOperand),
4377 VariableScale, Depth)) {
4378 // If even that didn't work, bail.
4379 AddrMode = BackupAddrMode;
4380 AddrModeInsts.resize(OldSize);
4381 return false;
4382 }
4383 }
4384
4385 return true;
4386 }
4387 case Instruction::SExt:
4388 case Instruction::ZExt: {
4389 Instruction *Ext = dyn_cast<Instruction>(AddrInst);
4390 if (!Ext)
4391 return false;
4392
4393 // Try to move this ext out of the way of the addressing mode.
4394 // Ask for a method for doing so.
4395 TypePromotionHelper::Action TPH =
4396 TypePromotionHelper::getAction(Ext, InsertedInsts, TLI, PromotedInsts);
4397 if (!TPH)
4398 return false;
4399
4400 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4401 TPT.getRestorationPoint();
4402 unsigned CreatedInstsCost = 0;
4403 unsigned ExtCost = !TLI.isExtFree(Ext);
4404 Value *PromotedOperand =
4405 TPH(Ext, TPT, PromotedInsts, CreatedInstsCost, nullptr, nullptr, TLI);
4406 // SExt has been moved away.
4407 // Thus either it will be rematched later in the recursive calls or it is
4408 // gone. Anyway, we must not fold it into the addressing mode at this point.
4409 // E.g.,
4410 // op = add opnd, 1
4411 // idx = ext op
4412 // addr = gep base, idx
4413 // is now:
4414 // promotedOpnd = ext opnd <- no match here
4415 // op = promoted_add promotedOpnd, 1 <- match (later in recursive calls)
4416 // addr = gep base, op <- match
4417 if (MovedAway)
4418 *MovedAway = true;
4419
4420 assert(PromotedOperand &&((PromotedOperand && "TypePromotionHelper should have filtered out those cases"
) ? static_cast<void> (0) : __assert_fail ("PromotedOperand && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4421, __PRETTY_FUNCTION__))
4421 "TypePromotionHelper should have filtered out those cases")((PromotedOperand && "TypePromotionHelper should have filtered out those cases"
) ? static_cast<void> (0) : __assert_fail ("PromotedOperand && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4421, __PRETTY_FUNCTION__))
;
4422
4423 ExtAddrMode BackupAddrMode = AddrMode;
4424 unsigned OldSize = AddrModeInsts.size();
4425
4426 if (!matchAddr(PromotedOperand, Depth) ||
4427 // The total of the new cost is equal to the cost of the created
4428 // instructions.
4429 // The total of the old cost is equal to the cost of the extension plus
4430 // what we have saved in the addressing mode.
4431 !isPromotionProfitable(CreatedInstsCost,
4432 ExtCost + (AddrModeInsts.size() - OldSize),
4433 PromotedOperand)) {
4434 AddrMode = BackupAddrMode;
4435 AddrModeInsts.resize(OldSize);
4436 LLVM_DEBUG(dbgs() << "Sign extension does not pay off: rollback\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Sign extension does not pay off: rollback\n"
; } } while (false)
;
4437 TPT.rollback(LastKnownGood);
4438 return false;
4439 }
4440 return true;
4441 }
4442 }
4443 return false;
4444}
4445
4446/// If we can, try to add the value of 'Addr' into the current addressing mode.
4447/// If Addr can't be added to AddrMode this returns false and leaves AddrMode
4448/// unmodified. This assumes that Addr is either a pointer type or intptr_t
4449/// for the target.
4450///
4451bool AddressingModeMatcher::matchAddr(Value *Addr, unsigned Depth) {
4452 // Start a transaction at this point that we will rollback if the matching
4453 // fails.
4454 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4455 TPT.getRestorationPoint();
4456 if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
4457 // Fold in immediates if legal for the target.
4458 AddrMode.BaseOffs += CI->getSExtValue();
4459 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4460 return true;
4461 AddrMode.BaseOffs -= CI->getSExtValue();
4462 } else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
4463 // If this is a global variable, try to fold it into the addressing mode.
4464 if (!AddrMode.BaseGV) {
4465 AddrMode.BaseGV = GV;
4466 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4467 return true;
4468 AddrMode.BaseGV = nullptr;
4469 }
4470 } else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
4471 ExtAddrMode BackupAddrMode = AddrMode;
4472 unsigned OldSize = AddrModeInsts.size();
4473
4474 // Check to see if it is possible to fold this operation.
4475 bool MovedAway = false;
4476 if (matchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
4477 // This instruction may have been moved away. If so, there is nothing
4478 // to check here.
4479 if (MovedAway)
4480 return true;
4481 // Okay, it's possible to fold this. Check to see if it is actually
4482 // *profitable* to do so. We use a simple cost model to avoid increasing
4483 // register pressure too much.
4484 if (I->hasOneUse() ||
4485 isProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
4486 AddrModeInsts.push_back(I);
4487 return true;
4488 }
4489
4490 // It isn't profitable to do this, roll back.
4491 //cerr << "NOT FOLDING: " << *I;
4492 AddrMode = BackupAddrMode;
4493 AddrModeInsts.resize(OldSize);
4494 TPT.rollback(LastKnownGood);
4495 }
4496 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
4497 if (matchOperationAddr(CE, CE->getOpcode(), Depth))
4498 return true;
4499 TPT.rollback(LastKnownGood);
4500 } else if (isa<ConstantPointerNull>(Addr)) {
4501 // Null pointer gets folded without affecting the addressing mode.
4502 return true;
4503 }
4504
4505 // Worse case, the target should support [reg] addressing modes. :)
4506 if (!AddrMode.HasBaseReg) {
4507 AddrMode.HasBaseReg = true;
4508 AddrMode.BaseReg = Addr;
4509 // Still check for legality in case the target supports [imm] but not [i+r].
4510 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4511 return true;
4512 AddrMode.HasBaseReg = false;
4513 AddrMode.BaseReg = nullptr;
4514 }
4515
4516 // If the base register is already taken, see if we can do [r+r].
4517 if (AddrMode.Scale == 0) {
4518 AddrMode.Scale = 1;
4519 AddrMode.ScaledReg = Addr;
4520 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4521 return true;
4522 AddrMode.Scale = 0;
4523 AddrMode.ScaledReg = nullptr;
4524 }
4525 // Couldn't match.
4526 TPT.rollback(LastKnownGood);
4527 return false;
4528}
4529
4530/// Check to see if all uses of OpVal by the specified inline asm call are due
4531/// to memory operands. If so, return true, otherwise return false.
4532static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
4533 const TargetLowering &TLI,
4534 const TargetRegisterInfo &TRI) {
4535 const Function *F = CI->getFunction();
4536 TargetLowering::AsmOperandInfoVector TargetConstraints =
4537 TLI.ParseConstraints(F->getParent()->getDataLayout(), &TRI,
4538 ImmutableCallSite(CI));
4539
4540 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
4541 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
4542
4543 // Compute the constraint code and ConstraintType to use.
4544 TLI.ComputeConstraintToUse(OpInfo, SDValue());
4545
4546 // If this asm operand is our Value*, and if it isn't an indirect memory
4547 // operand, we can't fold it!
4548 if (OpInfo.CallOperandVal == OpVal &&
4549 (OpInfo.ConstraintType != TargetLowering::C_Memory ||
4550 !OpInfo.isIndirect))
4551 return false;
4552 }
4553
4554 return true;
4555}
4556
4557// Max number of memory uses to look at before aborting the search to conserve
4558// compile time.
4559static constexpr int MaxMemoryUsesToScan = 20;
4560
4561/// Recursively walk all the uses of I until we find a memory use.
4562/// If we find an obviously non-foldable instruction, return true.
4563/// Add the ultimately found memory instructions to MemoryUses.
4564static bool FindAllMemoryUses(
4565 Instruction *I,
4566 SmallVectorImpl<std::pair<Instruction *, unsigned>> &MemoryUses,
4567 SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetLowering &TLI,
4568 const TargetRegisterInfo &TRI, bool OptSize, ProfileSummaryInfo *PSI,
4569 BlockFrequencyInfo *BFI, int SeenInsts = 0) {
4570 // If we already considered this instruction, we're done.
4571 if (!ConsideredInsts.insert(I).second)
4572 return false;
4573
4574 // If this is an obviously unfoldable instruction, bail out.
4575 if (!MightBeFoldableInst(I))
4576 return true;
4577
4578 // Loop over all the uses, recursively processing them.
4579 for (Use &U : I->uses()) {
4580 // Conservatively return true if we're seeing a large number or a deep chain
4581 // of users. This avoids excessive compilation times in pathological cases.
4582 if (SeenInsts++ >= MaxMemoryUsesToScan)
4583 return true;
4584
4585 Instruction *UserI = cast<Instruction>(U.getUser());
4586 if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) {
4587 MemoryUses.push_back(std::make_pair(LI, U.getOperandNo()));
4588 continue;
4589 }
4590
4591 if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) {
4592 unsigned opNo = U.getOperandNo();
4593 if (opNo != StoreInst::getPointerOperandIndex())
4594 return true; // Storing addr, not into addr.
4595 MemoryUses.push_back(std::make_pair(SI, opNo));
4596 continue;
4597 }
4598
4599 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(UserI)) {
4600 unsigned opNo = U.getOperandNo();
4601 if (opNo != AtomicRMWInst::getPointerOperandIndex())
4602 return true; // Storing addr, not into addr.
4603 MemoryUses.push_back(std::make_pair(RMW, opNo));
4604 continue;
4605 }
4606
4607 if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(UserI)) {
4608 unsigned opNo = U.getOperandNo();
4609 if (opNo != AtomicCmpXchgInst::getPointerOperandIndex())
4610 return true; // Storing addr, not into addr.
4611 MemoryUses.push_back(std::make_pair(CmpX, opNo));
4612 continue;
4613 }
4614
4615 if (CallInst *CI = dyn_cast<CallInst>(UserI)) {
4616 if (CI->hasFnAttr(Attribute::Cold)) {
4617 // If this is a cold call, we can sink the addressing calculation into
4618 // the cold path. See optimizeCallInst
4619 bool OptForSize = OptSize ||
4620 llvm::shouldOptimizeForSize(CI->getParent(), PSI, BFI);
4621 if (!OptForSize)
4622 continue;
4623 }
4624
4625 InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue());
4626 if (!IA) return true;
4627
4628 // If this is a memory operand, we're cool, otherwise bail out.
4629 if (!IsOperandAMemoryOperand(CI, IA, I, TLI, TRI))
4630 return true;
4631 continue;
4632 }
4633
4634 if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
4635 PSI, BFI, SeenInsts))
4636 return true;
4637 }
4638
4639 return false;
4640}
4641
4642/// Return true if Val is already known to be live at the use site that we're
4643/// folding it into. If so, there is no cost to include it in the addressing
4644/// mode. KnownLive1 and KnownLive2 are two values that we know are live at the
4645/// instruction already.
4646bool AddressingModeMatcher::valueAlreadyLiveAtInst(Value *Val,Value *KnownLive1,
4647 Value *KnownLive2) {
4648 // If Val is either of the known-live values, we know it is live!
4649 if (Val == nullptr || Val == KnownLive1 || Val == KnownLive2)
4650 return true;
4651
4652 // All values other than instructions and arguments (e.g. constants) are live.
4653 if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true;
4654
4655 // If Val is a constant sized alloca in the entry block, it is live, this is
4656 // true because it is just a reference to the stack/frame pointer, which is
4657 // live for the whole function.
4658 if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
4659 if (AI->isStaticAlloca())
4660 return true;
4661
4662 // Check to see if this value is already used in the memory instruction's
4663 // block. If so, it's already live into the block at the very least, so we
4664 // can reasonably fold it.
4665 return Val->isUsedInBasicBlock(MemoryInst->getParent());
4666}
4667
4668/// It is possible for the addressing mode of the machine to fold the specified
4669/// instruction into a load or store that ultimately uses it.
4670/// However, the specified instruction has multiple uses.
4671/// Given this, it may actually increase register pressure to fold it
4672/// into the load. For example, consider this code:
4673///
4674/// X = ...
4675/// Y = X+1
4676/// use(Y) -> nonload/store
4677/// Z = Y+1
4678/// load Z
4679///
4680/// In this case, Y has multiple uses, and can be folded into the load of Z
4681/// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to
4682/// be live at the use(Y) line. If we don't fold Y into load Z, we use one
4683/// fewer register. Since Y can't be folded into "use(Y)" we don't increase the
4684/// number of computations either.
4685///
4686/// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If
4687/// X was live across 'load Z' for other reasons, we actually *would* want to
4688/// fold the addressing mode in the Z case. This would make Y die earlier.
4689bool AddressingModeMatcher::
4690isProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore,
4691 ExtAddrMode &AMAfter) {
4692 if (IgnoreProfitability) return true;
4693
4694 // AMBefore is the addressing mode before this instruction was folded into it,
4695 // and AMAfter is the addressing mode after the instruction was folded. Get
4696 // the set of registers referenced by AMAfter and subtract out those
4697 // referenced by AMBefore: this is the set of values which folding in this
4698 // address extends the lifetime of.
4699 //
4700 // Note that there are only two potential values being referenced here,
4701 // BaseReg and ScaleReg (global addresses are always available, as are any
4702 // folded immediates).
4703 Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;
4704
4705 // If the BaseReg or ScaledReg was referenced by the previous addrmode, their
4706 // lifetime wasn't extended by adding this instruction.
4707 if (valueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
4708 BaseReg = nullptr;
4709 if (valueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
4710 ScaledReg = nullptr;
4711
4712 // If folding this instruction (and it's subexprs) didn't extend any live
4713 // ranges, we're ok with it.
4714 if (!BaseReg && !ScaledReg)
4715 return true;
4716
4717 // If all uses of this instruction can have the address mode sunk into them,
4718 // we can remove the addressing mode and effectively trade one live register
4719 // for another (at worst.) In this context, folding an addressing mode into
4720 // the use is just a particularly nice way of sinking it.
4721 SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
4722 SmallPtrSet<Instruction*, 16> ConsideredInsts;
4723 if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
4724 PSI, BFI))
4725 return false; // Has a non-memory, non-foldable use!
4726
4727 // Now that we know that all uses of this instruction are part of a chain of
4728 // computation involving only operations that could theoretically be folded
4729 // into a memory use, loop over each of these memory operation uses and see
4730 // if they could *actually* fold the instruction. The assumption is that
4731 // addressing modes are cheap and that duplicating the computation involved
4732 // many times is worthwhile, even on a fastpath. For sinking candidates
4733 // (i.e. cold call sites), this serves as a way to prevent excessive code
4734 // growth since most architectures have some reasonable small and fast way to
4735 // compute an effective address. (i.e LEA on x86)
4736 SmallVector<Instruction*, 32> MatchedAddrModeInsts;
4737 for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) {
4738 Instruction *User = MemoryUses[i].first;
4739 unsigned OpNo = MemoryUses[i].second;
4740
4741 // Get the access type of this use. If the use isn't a pointer, we don't
4742 // know what it accesses.
4743 Value *Address = User->getOperand(OpNo);
4744 PointerType *AddrTy = dyn_cast<PointerType>(Address->getType());
4745 if (!AddrTy)
4746 return false;
4747 Type *AddressAccessTy = AddrTy->getElementType();
4748 unsigned AS = AddrTy->getAddressSpace();
4749
4750 // Do a match against the root of this address, ignoring profitability. This
4751 // will tell us if the addressing mode for the memory operation will
4752 // *actually* cover the shared instruction.
4753 ExtAddrMode Result;
4754 std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
4755 0);
4756 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4757 TPT.getRestorationPoint();
4758 AddressingModeMatcher Matcher(
4759 MatchedAddrModeInsts, TLI, TRI, AddressAccessTy, AS, MemoryInst, Result,
4760 InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI, BFI);
4761 Matcher.IgnoreProfitability = true;
4762 bool Success = Matcher.matchAddr(Address, 0);
4763 (void)Success; assert(Success && "Couldn't select *anything*?")((Success && "Couldn't select *anything*?") ? static_cast
<void> (0) : __assert_fail ("Success && \"Couldn't select *anything*?\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4763, __PRETTY_FUNCTION__))
;
4764
4765 // The match was to check the profitability, the changes made are not
4766 // part of the original matcher. Therefore, they should be dropped
4767 // otherwise the original matcher will not present the right state.
4768 TPT.rollback(LastKnownGood);
4769
4770 // If the match didn't cover I, then it won't be shared by it.
4771 if (!is_contained(MatchedAddrModeInsts, I))
4772 return false;
4773
4774 MatchedAddrModeInsts.clear();
4775 }
4776
4777 return true;
4778}
4779
4780/// Return true if the specified values are defined in a
4781/// different basic block than BB.
4782static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
4783 if (Instruction *I = dyn_cast<Instruction>(V))
4784 return I->getParent() != BB;
4785 return false;
4786}
4787
4788/// Sink addressing mode computation immediate before MemoryInst if doing so
4789/// can be done without increasing register pressure. The need for the
4790/// register pressure constraint means this can end up being an all or nothing
4791/// decision for all uses of the same addressing computation.
4792///
4793/// Load and Store Instructions often have addressing modes that can do
4794/// significant amounts of computation. As such, instruction selection will try
4795/// to get the load or store to do as much computation as possible for the
4796/// program. The problem is that isel can only see within a single block. As
4797/// such, we sink as much legal addressing mode work into the block as possible.
4798///
4799/// This method is used to optimize both load/store and inline asms with memory
4800/// operands. It's also used to sink addressing computations feeding into cold
4801/// call sites into their (cold) basic block.
4802///
4803/// The motivation for handling sinking into cold blocks is that doing so can
4804/// both enable other address mode sinking (by satisfying the register pressure
4805/// constraint above), and reduce register pressure globally (by removing the
4806/// addressing mode computation from the fast path entirely.).
4807bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
4808 Type *AccessTy, unsigned AddrSpace) {
4809 Value *Repl = Addr;
4810
4811 // Try to collapse single-value PHI nodes. This is necessary to undo
4812 // unprofitable PRE transformations.
4813 SmallVector<Value*, 8> worklist;
4814 SmallPtrSet<Value*, 16> Visited;
4815 worklist.push_back(Addr);
4816
4817 // Use a worklist to iteratively look through PHI and select nodes, and
4818 // ensure that the addressing mode obtained from the non-PHI/select roots of
4819 // the graph are compatible.
4820 bool PhiOrSelectSeen = false;
4821 SmallVector<Instruction*, 16> AddrModeInsts;
4822 const SimplifyQuery SQ(*DL, TLInfo);
4823 AddressingModeCombiner AddrModes(SQ, Addr);
4824 TypePromotionTransaction TPT(RemovedInsts);
4825 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4826 TPT.getRestorationPoint();
4827 while (!worklist.empty()) {
4828 Value *V = worklist.back();
4829 worklist.pop_back();
4830
4831 // We allow traversing cyclic Phi nodes.
4832 // In case of success after this loop we ensure that traversing through
4833 // Phi nodes ends up with all cases to compute address of the form
4834 // BaseGV + Base + Scale * Index + Offset
4835 // where Scale and Offset are constans and BaseGV, Base and Index
4836 // are exactly the same Values in all cases.
4837 // It means that BaseGV, Scale and Offset dominate our memory instruction
4838 // and have the same value as they had in address computation represented
4839 // as Phi. So we can safely sink address computation to memory instruction.
4840 if (!Visited.insert(V).second)
4841 continue;
4842
4843 // For a PHI node, push all of its incoming values.
4844 if (PHINode *P = dyn_cast<PHINode>(V)) {
4845 for (Value *IncValue : P->incoming_values())
4846 worklist.push_back(IncValue);
4847 PhiOrSelectSeen = true;
4848 continue;
4849 }
4850 // Similar for select.
4851 if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
4852 worklist.push_back(SI->getFalseValue());
4853 worklist.push_back(SI->getTrueValue());
4854 PhiOrSelectSeen = true;
4855 continue;
4856 }
4857
4858 // For non-PHIs, determine the addressing mode being computed. Note that
4859 // the result may differ depending on what other uses our candidate
4860 // addressing instructions might have.
4861 AddrModeInsts.clear();
4862 std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
4863 0);
4864 ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
4865 V, AccessTy, AddrSpace, MemoryInst, AddrModeInsts, *TLI, *TRI,
4866 InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI,
4867 BFI.get());
4868
4869 GetElementPtrInst *GEP = LargeOffsetGEP.first;
4870 if (GEP && !NewGEPBases.count(GEP)) {
4871 // If splitting the underlying data structure can reduce the offset of a
4872 // GEP, collect the GEP. Skip the GEPs that are the new bases of
4873 // previously split data structures.
4874 LargeOffsetGEPMap[GEP->getPointerOperand()].push_back(LargeOffsetGEP);
4875 if (LargeOffsetGEPID.find(GEP) == LargeOffsetGEPID.end())
4876 LargeOffsetGEPID[GEP] = LargeOffsetGEPID.size();
4877 }
4878
4879 NewAddrMode.OriginalValue = V;
4880 if (!AddrModes.addNewAddrMode(NewAddrMode))
4881 break;
4882 }
4883
4884 // Try to combine the AddrModes we've collected. If we couldn't collect any,
4885 // or we have multiple but either couldn't combine them or combining them
4886 // wouldn't do anything useful, bail out now.
4887 if (!AddrModes.combineAddrModes()) {
4888 TPT.rollback(LastKnownGood);
4889 return false;
4890 }
4891 TPT.commit();
4892
4893 // Get the combined AddrMode (or the only AddrMode, if we only had one).
4894 ExtAddrMode AddrMode = AddrModes.getAddrMode();
4895
4896 // If all the instructions matched are already in this BB, don't do anything.
4897 // If we saw a Phi node then it is not local definitely, and if we saw a select
4898 // then we want to push the address calculation past it even if it's already
4899 // in this BB.
4900 if (!PhiOrSelectSeen && none_of(AddrModeInsts, [&](Value *V) {
4901 return IsNonLocalValue(V, MemoryInst->getParent());
4902 })) {
4903 LLVM_DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Found local addrmode: "
<< AddrMode << "\n"; } } while (false)
4904 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Found local addrmode: "
<< AddrMode << "\n"; } } while (false)
;
4905 return false;
4906 }
4907
4908 // Insert this computation right after this user. Since our caller is
4909 // scanning from the top of the BB to the bottom, reuse of the expr are
4910 // guaranteed to happen later.
4911 IRBuilder<> Builder(MemoryInst);
4912
4913 // Now that we determined the addressing expression we want to use and know
4914 // that we have to sink it into this block. Check to see if we have already
4915 // done this for some other load/store instr in this block. If so, reuse
4916 // the computation. Before attempting reuse, check if the address is valid
4917 // as it may have been erased.
4918
4919 WeakTrackingVH SunkAddrVH = SunkAddrs[Addr];
4920
4921 Value * SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr;
4922 if (SunkAddr) {
4923 LLVM_DEBUG(dbgs() << "CGP: Reusing nonlocal addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Reusing nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
4924 << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Reusing nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
4925 if (SunkAddr->getType() != Addr->getType())
4926 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
4927 } else if (AddrSinkUsingGEPs || (!AddrSinkUsingGEPs.getNumOccurrences() &&
4928 SubtargetInfo->addrSinkUsingGEPs())) {
4929 // By default, we use the GEP-based method when AA is used later. This
4930 // prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
4931 LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
4932 << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
4933 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
4934 Value *ResultPtr = nullptr, *ResultIndex = nullptr;
4935
4936 // First, find the pointer.
4937 if (AddrMode.BaseReg && AddrMode.BaseReg->getType()->isPointerTy()) {
4938 ResultPtr = AddrMode.BaseReg;
4939 AddrMode.BaseReg = nullptr;
4940 }
4941
4942 if (AddrMode.Scale && AddrMode.ScaledReg->getType()->isPointerTy()) {
4943 // We can't add more than one pointer together, nor can we scale a
4944 // pointer (both of which seem meaningless).
4945 if (ResultPtr || AddrMode.Scale != 1)
4946 return false;
4947
4948 ResultPtr = AddrMode.ScaledReg;
4949 AddrMode.Scale = 0;
4950 }
4951
4952 // It is only safe to sign extend the BaseReg if we know that the math
4953 // required to create it did not overflow before we extend it. Since
4954 // the original IR value was tossed in favor of a constant back when
4955 // the AddrMode was created we need to bail out gracefully if widths
4956 // do not match instead of extending it.
4957 //
4958 // (See below for code to add the scale.)
4959 if (AddrMode.Scale) {
4960 Type *ScaledRegTy = AddrMode.ScaledReg->getType();
4961 if (cast<IntegerType>(IntPtrTy)->getBitWidth() >
4962 cast<IntegerType>(ScaledRegTy)->getBitWidth())
4963 return false;
4964 }
4965
4966 if (AddrMode.BaseGV) {
4967 if (ResultPtr)
4968 return false;
4969
4970 ResultPtr = AddrMode.BaseGV;
4971 }
4972
4973 // If the real base value actually came from an inttoptr, then the matcher
4974 // will look through it and provide only the integer value. In that case,
4975 // use it here.
4976 if (!DL->isNonIntegralPointerType(Addr->getType())) {
4977 if (!ResultPtr && AddrMode.BaseReg) {
4978 ResultPtr = Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(),
4979 "sunkaddr");
4980 AddrMode.BaseReg = nullptr;
4981 } else if (!ResultPtr && AddrMode.Scale == 1) {
4982 ResultPtr = Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(),
4983 "sunkaddr");
4984 AddrMode.Scale = 0;
4985 }
4986 }
4987
4988 if (!ResultPtr &&
4989 !AddrMode.BaseReg && !AddrMode.Scale && !AddrMode.BaseOffs) {
4990 SunkAddr = Constant::getNullValue(Addr->getType());
4991 } else if (!ResultPtr) {
4992 return false;
4993 } else {
4994 Type *I8PtrTy =
4995 Builder.getInt8PtrTy(Addr->getType()->getPointerAddressSpace());
4996 Type *I8Ty = Builder.getInt8Ty();
4997
4998 // Start with the base register. Do this first so that subsequent address
4999 // matching finds it last, which will prevent it from trying to match it
5000 // as the scaled value in case it happens to be a mul. That would be
5001 // problematic if we've sunk a different mul for the scale, because then
5002 // we'd end up sinking both muls.
5003 if (AddrMode.BaseReg) {
5004 Value *V = AddrMode.BaseReg;
5005 if (V->getType() != IntPtrTy)
5006 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
5007
5008 ResultIndex = V;
5009 }
5010
5011 // Add the scale value.
5012 if (AddrMode.Scale) {
5013 Value *V = AddrMode.ScaledReg;
5014 if (V->getType() == IntPtrTy) {
5015 // done.
5016 } else {
5017 assert(cast<IntegerType>(IntPtrTy)->getBitWidth() <((cast<IntegerType>(IntPtrTy)->getBitWidth() < cast
<IntegerType>(V->getType())->getBitWidth() &&
"We can't transform if ScaledReg is too narrow") ? static_cast
<void> (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5019, __PRETTY_FUNCTION__))
5018 cast<IntegerType>(V->getType())->getBitWidth() &&((cast<IntegerType>(IntPtrTy)->getBitWidth() < cast
<IntegerType>(V->getType())->getBitWidth() &&
"We can't transform if ScaledReg is too narrow") ? static_cast
<void> (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5019, __PRETTY_FUNCTION__))
5019 "We can't transform if ScaledReg is too narrow")((cast<IntegerType>(IntPtrTy)->getBitWidth() < cast
<IntegerType>(V->getType())->getBitWidth() &&
"We can't transform if ScaledReg is too narrow") ? static_cast
<void> (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5019, __PRETTY_FUNCTION__))
;
5020 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
5021 }
5022
5023 if (AddrMode.Scale != 1)
5024 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
5025 "sunkaddr");
5026 if (ResultIndex)
5027 ResultIndex = Builder.CreateAdd(ResultIndex, V, "sunkaddr");
5028 else
5029 ResultIndex = V;
5030 }
5031
5032 // Add in the Base Offset if present.
5033 if (AddrMode.BaseOffs) {
5034 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
5035 if (ResultIndex) {
5036 // We need to add this separately from the scale above to help with
5037 // SDAG consecutive load/store merging.
5038 if (ResultPtr->getType() != I8PtrTy)
5039 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
5040 ResultPtr =
5041 AddrMode.InBounds
5042 ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
5043 "sunkaddr")
5044 : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
5045 }
5046
5047 ResultIndex = V;
5048 }
5049
5050 if (!ResultIndex) {
5051 SunkAddr = ResultPtr;
5052 } else {
5053 if (ResultPtr->getType() != I8PtrTy)
5054 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
5055 SunkAddr =
5056 AddrMode.InBounds
5057 ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
5058 "sunkaddr")
5059 : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
5060 }
5061
5062 if (SunkAddr->getType() != Addr->getType())
5063 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
5064 }
5065 } else {
5066 // We'd require a ptrtoint/inttoptr down the line, which we can't do for
5067 // non-integral pointers, so in that case bail out now.
5068 Type *BaseTy = AddrMode.BaseReg ? AddrMode.BaseReg->getType() : nullptr;
5069 Type *ScaleTy = AddrMode.Scale ? AddrMode.ScaledReg->getType() : nullptr;
5070 PointerType *BasePtrTy = dyn_cast_or_null<PointerType>(BaseTy);
5071 PointerType *ScalePtrTy = dyn_cast_or_null<PointerType>(ScaleTy);
5072 if (DL->isNonIntegralPointerType(Addr->getType()) ||
5073 (BasePtrTy && DL->isNonIntegralPointerType(BasePtrTy)) ||
5074 (ScalePtrTy && DL->isNonIntegralPointerType(ScalePtrTy)) ||
5075 (AddrMode.BaseGV &&
5076 DL->isNonIntegralPointerType(AddrMode.BaseGV->getType())))
5077 return false;
5078
5079 LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
5080 << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
5081 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
5082 Value *Result = nullptr;
5083
5084 // Start with the base register. Do this first so that subsequent address
5085 // matching finds it last, which will prevent it from trying to match it
5086 // as the scaled value in case it happens to be a mul. That would be
5087 // problematic if we've sunk a different mul for the scale, because then
5088 // we'd end up sinking both muls.
5089 if (AddrMode.BaseReg) {
5090 Value *V = AddrMode.BaseReg;
5091 if (V->getType()->isPointerTy())
5092 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
5093 if (V->getType() != IntPtrTy)
5094 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
5095 Result = V;
5096 }
5097
5098 // Add the scale value.
5099 if (AddrMode.Scale) {
5100 Value *V = AddrMode.ScaledReg;
5101 if (V->getType() == IntPtrTy) {
5102 // done.
5103 } else if (V->getType()->isPointerTy()) {
5104 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
5105 } else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
5106 cast<IntegerType>(V->getType())->getBitWidth()) {
5107 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
5108 } else {
5109 // It is only safe to sign extend the BaseReg if we know that the math
5110 // required to create it did not overflow before we extend it. Since
5111 // the original IR value was tossed in favor of a constant back when
5112 // the AddrMode was created we need to bail out gracefully if widths
5113 // do not match instead of extending it.
5114 Instruction *I = dyn_cast_or_null<Instruction>(Result);
5115 if (I && (Result != AddrMode.BaseReg))
5116 I->eraseFromParent();
5117 return false;
5118 }
5119 if (AddrMode.Scale != 1)
5120 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
5121 "sunkaddr");
5122 if (Result)
5123 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5124 else
5125 Result = V;
5126 }
5127
5128 // Add in the BaseGV if present.
5129 if (AddrMode.BaseGV) {
5130 Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
5131 if (Result)
5132 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5133 else
5134 Result = V;
5135 }
5136
5137 // Add in the Base Offset if present.
5138 if (AddrMode.BaseOffs) {
5139 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
5140 if (Result)
5141 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5142 else
5143 Result = V;
5144 }
5145
5146 if (!Result)
5147 SunkAddr = Constant::getNullValue(Addr->getType());
5148 else
5149 SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr");
5150 }
5151
5152 MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
5153 // Store the newly computed address into the cache. In the case we reused a
5154 // value, this should be idempotent.
5155 SunkAddrs[Addr] = WeakTrackingVH(SunkAddr);
5156
5157 // If we have no uses, recursively delete the value and all dead instructions
5158 // using it.
5159 if (Repl->use_empty()) {
5160 // This can cause recursive deletion, which can invalidate our iterator.
5161 // Use a WeakTrackingVH to hold onto it in case this happens.
5162 Value *CurValue = &*CurInstIterator;
5163 WeakTrackingVH IterHandle(CurValue);
5164 BasicBlock *BB = CurInstIterator->getParent();
5165
5166 RecursivelyDeleteTriviallyDeadInstructions(Repl, TLInfo);
5167
5168 if (IterHandle != CurValue) {
5169 // If the iterator instruction was recursively deleted, start over at the
5170 // start of the block.
5171 CurInstIterator = BB->begin();
5172 SunkAddrs.clear();
5173 }
5174 }
5175 ++NumMemoryInsts;
5176 return true;
5177}
5178
5179/// If there are any memory operands, use OptimizeMemoryInst to sink their
5180/// address computing into the block when possible / profitable.
5181bool CodeGenPrepare::optimizeInlineAsmInst(CallInst *CS) {
5182 bool MadeChange = false;
5183
5184 const TargetRegisterInfo *TRI =
5185 TM->getSubtargetImpl(*CS->getFunction())->getRegisterInfo();
5186 TargetLowering::AsmOperandInfoVector TargetConstraints =
5187 TLI->ParseConstraints(*DL, TRI, CS);
5188 unsigned ArgNo = 0;
5189 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
5190 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
5191
5192 // Compute the constraint code and ConstraintType to use.
5193 TLI->ComputeConstraintToUse(OpInfo, SDValue());
5194
5195 if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
5196 OpInfo.isIndirect) {
5197 Value *OpVal = CS->getArgOperand(ArgNo++);
5198 MadeChange |= optimizeMemoryInst(CS, OpVal, OpVal->getType(), ~0u);
5199 } else if (OpInfo.Type == InlineAsm::isInput)
5200 ArgNo++;
5201 }
5202
5203 return MadeChange;
5204}
5205
5206/// Check if all the uses of \p Val are equivalent (or free) zero or
5207/// sign extensions.
5208static bool hasSameExtUse(Value *Val, const TargetLowering &TLI) {
5209 assert(!Val->use_empty() && "Input must have at least one use")((!Val->use_empty() && "Input must have at least one use"
) ? static_cast<void> (0) : __assert_fail ("!Val->use_empty() && \"Input must have at least one use\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5209, __PRETTY_FUNCTION__))
;
5210 const Instruction *FirstUser = cast<Instruction>(*Val->user_begin());
5211 bool IsSExt = isa<SExtInst>(FirstUser);
5212 Type *ExtTy = FirstUser->getType();
5213 for (const User *U : Val->users()) {
5214 const Instruction *UI = cast<Instruction>(U);
5215 if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI)))
5216 return false;
5217 Type *CurTy = UI->getType();
5218 // Same input and output types: Same instruction after CSE.
5219 if (CurTy == ExtTy)
5220 continue;
5221
5222 // If IsSExt is true, we are in this situation:
5223 // a = Val
5224 // b = sext ty1 a to ty2
5225 // c = sext ty1 a to ty3
5226 // Assuming ty2 is shorter than ty3, this could be turned into:
5227 // a = Val
5228 // b = sext ty1 a to ty2
5229 // c = sext ty2 b to ty3
5230 // However, the last sext is not free.
5231 if (IsSExt)
5232 return false;
5233
5234 // This is a ZExt, maybe this is free to extend from one type to another.
5235 // In that case, we would not account for a different use.
5236 Type *NarrowTy;
5237 Type *LargeTy;
5238 if (ExtTy->getScalarType()->getIntegerBitWidth() >
5239 CurTy->getScalarType()->getIntegerBitWidth()) {
5240 NarrowTy = CurTy;
5241 LargeTy = ExtTy;
5242 } else {
5243 NarrowTy = ExtTy;
5244 LargeTy = CurTy;
5245 }
5246
5247 if (!TLI.isZExtFree(NarrowTy, LargeTy))
5248 return false;
5249 }
5250 // All uses are the same or can be derived from one another for free.
5251 return true;
5252}
5253
5254/// Try to speculatively promote extensions in \p Exts and continue
5255/// promoting through newly promoted operands recursively as far as doing so is
5256/// profitable. Save extensions profitably moved up, in \p ProfitablyMovedExts.
5257/// When some promotion happened, \p TPT contains the proper state to revert
5258/// them.
5259///
5260/// \return true if some promotion happened, false otherwise.
5261bool CodeGenPrepare::tryToPromoteExts(
5262 TypePromotionTransaction &TPT, const SmallVectorImpl<Instruction *> &Exts,
5263 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
5264 unsigned CreatedInstsCost) {
5265 bool Promoted = false;
5266
5267 // Iterate over all the extensions to try to promote them.
5268 for (auto I : Exts) {
5269 // Early check if we directly have ext(load).
5270 if (isa<LoadInst>(I->getOperand(0))) {
5271 ProfitablyMovedExts.push_back(I);
5272 continue;
5273 }
5274
5275 // Check whether or not we want to do any promotion. The reason we have
5276 // this check inside the for loop is to catch the case where an extension
5277 // is directly fed by a load because in such case the extension can be moved
5278 // up without any promotion on its operands.
5279 if (!TLI->enableExtLdPromotion() || DisableExtLdPromotion)
5280 return false;
5281
5282 // Get the action to perform the promotion.
5283 TypePromotionHelper::Action TPH =
5284 TypePromotionHelper::getAction(I, InsertedInsts, *TLI, PromotedInsts);
5285 // Check if we can promote.
5286 if (!TPH) {
5287 // Save the current extension as we cannot move up through its operand.
5288 ProfitablyMovedExts.push_back(I);
5289 continue;
5290 }
5291
5292 // Save the current state.
5293 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
5294 TPT.getRestorationPoint();
5295 SmallVector<Instruction *, 4> NewExts;
5296 unsigned NewCreatedInstsCost = 0;
5297 unsigned ExtCost = !TLI->isExtFree(I);
5298 // Promote.
5299 Value *PromotedVal = TPH(I, TPT, PromotedInsts, NewCreatedInstsCost,
5300 &NewExts, nullptr, *TLI);
5301 assert(PromotedVal &&((PromotedVal && "TypePromotionHelper should have filtered out those cases"
) ? static_cast<void> (0) : __assert_fail ("PromotedVal && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5302, __PRETTY_FUNCTION__))
5302 "TypePromotionHelper should have filtered out those cases")((PromotedVal && "TypePromotionHelper should have filtered out those cases"
) ? static_cast<void> (0) : __assert_fail ("PromotedVal && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5302, __PRETTY_FUNCTION__))
;
5303
5304 // We would be able to merge only one extension in a load.
5305 // Therefore, if we have more than 1 new extension we heuristically
5306 // cut this search path, because it means we degrade the code quality.
5307 // With exactly 2, the transformation is neutral, because we will merge
5308 // one extension but leave one. However, we optimistically keep going,
5309 // because the new extension may be removed too.
5310 long long TotalCreatedInstsCost = CreatedInstsCost + NewCreatedInstsCost;
5311 // FIXME: It would be possible to propagate a negative value instead of
5312 // conservatively ceiling it to 0.
5313 TotalCreatedInstsCost =
5314 std::max((long long)0, (TotalCreatedInstsCost - ExtCost));
5315 if (!StressExtLdPromotion &&
5316 (TotalCreatedInstsCost > 1 ||
5317 !isPromotedInstructionLegal(*TLI, *DL, PromotedVal))) {
5318 // This promotion is not profitable, rollback to the previous state, and
5319 // save the current extension in ProfitablyMovedExts as the latest
5320 // speculative promotion turned out to be unprofitable.
5321 TPT.rollback(LastKnownGood);
5322 ProfitablyMovedExts.push_back(I);
5323 continue;
5324 }
5325 // Continue promoting NewExts as far as doing so is profitable.
5326 SmallVector<Instruction *, 2> NewlyMovedExts;
5327 (void)tryToPromoteExts(TPT, NewExts, NewlyMovedExts, TotalCreatedInstsCost);
5328 bool NewPromoted = false;
5329 for (auto ExtInst : NewlyMovedExts) {
5330 Instruction *MovedExt = cast<Instruction>(ExtInst);
5331 Value *ExtOperand = MovedExt->getOperand(0);
5332 // If we have reached to a load, we need this extra profitability check
5333 // as it could potentially be merged into an ext(load).
5334 if (isa<LoadInst>(ExtOperand) &&
5335 !(StressExtLdPromotion || NewCreatedInstsCost <= ExtCost ||
5336 (ExtOperand->hasOneUse() || hasSameExtUse(ExtOperand, *TLI))))
5337 continue;
5338
5339 ProfitablyMovedExts.push_back(MovedExt);
5340 NewPromoted = true;
5341 }
5342
5343 // If none of speculative promotions for NewExts is profitable, rollback
5344 // and save the current extension (I) as the last profitable extension.
5345 if (!NewPromoted) {
5346 TPT.rollback(LastKnownGood);
5347 ProfitablyMovedExts.push_back(I);
5348 continue;
5349 }
5350 // The promotion is profitable.
5351 Promoted = true;
5352 }
5353 return Promoted;
5354}
5355
5356/// Merging redundant sexts when one is dominating the other.
5357bool CodeGenPrepare::mergeSExts(Function &F) {
5358 bool Changed = false;
5359 for (auto &Entry : ValToSExtendedUses) {
5360 SExts &Insts = Entry.second;
5361 SExts CurPts;
5362 for (Instruction *Inst : Insts) {
5363 if (RemovedInsts.count(Inst) || !isa<SExtInst>(Inst) ||
5364 Inst->getOperand(0) != Entry.first)
5365 continue;
5366 bool inserted = false;
5367 for (auto &Pt : CurPts) {
5368 if (getDT(F).dominates(Inst, Pt)) {
5369 Pt->replaceAllUsesWith(Inst);
5370 RemovedInsts.insert(Pt);
5371 Pt->removeFromParent();
5372 Pt = Inst;
5373 inserted = true;
5374 Changed = true;
5375 break;
5376 }
5377 if (!getDT(F).dominates(Pt, Inst))
5378 // Give up if we need to merge in a common dominator as the
5379 // experiments show it is not profitable.
5380 continue;
5381 Inst->replaceAllUsesWith(Pt);
5382 RemovedInsts.insert(Inst);
5383 Inst->removeFromParent();
5384 inserted = true;
5385 Changed = true;
5386 break;
5387 }
5388 if (!inserted)
5389 CurPts.push_back(Inst);
5390 }
5391 }
5392 return Changed;
5393}
5394
5395// Spliting large data structures so that the GEPs accessing them can have
5396// smaller offsets so that they can be sunk to the same blocks as their users.
5397// For example, a large struct starting from %base is splitted into two parts
5398// where the second part starts from %new_base.
5399//
5400// Before:
5401// BB0:
5402// %base =
5403//
5404// BB1:
5405// %gep0 = gep %base, off0
5406// %gep1 = gep %base, off1
5407// %gep2 = gep %base, off2
5408//
5409// BB2:
5410// %load1 = load %gep0
5411// %load2 = load %gep1
5412// %load3 = load %gep2
5413//
5414// After:
5415// BB0:
5416// %base =
5417// %new_base = gep %base, off0
5418//
5419// BB1:
5420// %new_gep0 = %new_base
5421// %new_gep1 = gep %new_base, off1 - off0
5422// %new_gep2 = gep %new_base, off2 - off0
5423//
5424// BB2:
5425// %load1 = load i32, i32* %new_gep0
5426// %load2 = load i32, i32* %new_gep1
5427// %load3 = load i32, i32* %new_gep2
5428//
5429// %new_gep1 and %new_gep2 can be sunk to BB2 now after the splitting because
5430// their offsets are smaller enough to fit into the addressing mode.
5431bool CodeGenPrepare::splitLargeGEPOffsets() {
5432 bool Changed = false;
5433 for (auto &Entry : LargeOffsetGEPMap) {
5434 Value *OldBase = Entry.first;
5435 SmallVectorImpl<std::pair<AssertingVH<GetElementPtrInst>, int64_t>>
5436 &LargeOffsetGEPs = Entry.second;
5437 auto compareGEPOffset =
5438 [&](const std::pair<GetElementPtrInst *, int64_t> &LHS,
5439 const std::pair<GetElementPtrInst *, int64_t> &RHS) {
5440 if (LHS.first == RHS.first)
5441 return false;
5442 if (LHS.second != RHS.second)
5443 return LHS.second < RHS.second;
5444 return LargeOffsetGEPID[LHS.first] < LargeOffsetGEPID[RHS.first];
5445 };
5446 // Sorting all the GEPs of the same data structures based on the offsets.
5447 llvm::sort(LargeOffsetGEPs, compareGEPOffset);
5448 LargeOffsetGEPs.erase(
5449 std::unique(LargeOffsetGEPs.begin(), LargeOffsetGEPs.end()),
5450 LargeOffsetGEPs.end());
5451 // Skip if all the GEPs have the same offsets.
5452 if (LargeOffsetGEPs.front().second == LargeOffsetGEPs.back().second)
5453 continue;
5454 GetElementPtrInst *BaseGEP = LargeOffsetGEPs.begin()->first;
5455 int64_t BaseOffset = LargeOffsetGEPs.begin()->second;
5456 Value *NewBaseGEP = nullptr;
5457
5458 auto LargeOffsetGEP = LargeOffsetGEPs.begin();
5459 while (LargeOffsetGEP != LargeOffsetGEPs.end()) {
5460 GetElementPtrInst *GEP = LargeOffsetGEP->first;
5461 int64_t Offset = LargeOffsetGEP->second;
5462 if (Offset != BaseOffset) {
5463 TargetLowering::AddrMode AddrMode;
5464 AddrMode.BaseOffs = Offset - BaseOffset;
5465 // The result type of the GEP might not be the type of the memory
5466 // access.
5467 if (!TLI->isLegalAddressingMode(*DL, AddrMode,
5468 GEP->getResultElementType(),
5469 GEP->getAddressSpace())) {
5470 // We need to create a new base if the offset to the current base is
5471 // too large to fit into the addressing mode. So, a very large struct
5472 // may be splitted into several parts.
5473 BaseGEP = GEP;
5474 BaseOffset = Offset;
5475 NewBaseGEP = nullptr;
5476 }
5477 }
5478
5479 // Generate a new GEP to replace the current one.
5480 LLVMContext &Ctx = GEP->getContext();
5481 Type *IntPtrTy = DL->getIntPtrType(GEP->getType());
5482 Type *I8PtrTy =
5483 Type::getInt8PtrTy(Ctx, GEP->getType()->getPointerAddressSpace());
5484 Type *I8Ty = Type::getInt8Ty(Ctx);
5485
5486 if (!NewBaseGEP) {
5487 // Create a new base if we don't have one yet. Find the insertion
5488 // pointer for the new base first.
5489 BasicBlock::iterator NewBaseInsertPt;
5490 BasicBlock *NewBaseInsertBB;
5491 if (auto *BaseI = dyn_cast<Instruction>(OldBase)) {
5492 // If the base of the struct is an instruction, the new base will be
5493 // inserted close to it.
5494 NewBaseInsertBB = BaseI->getParent();
5495 if (isa<PHINode>(BaseI))
5496 NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
5497 else if (InvokeInst *Invoke = dyn_cast<InvokeInst>(BaseI)) {
5498 NewBaseInsertBB =
5499 SplitEdge(NewBaseInsertBB, Invoke->getNormalDest());
5500 NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
5501 } else
5502 NewBaseInsertPt = std::next(BaseI->getIterator());
5503 } else {
5504 // If the current base is an argument or global value, the new base
5505 // will be inserted to the entry block.
5506 NewBaseInsertBB = &BaseGEP->getFunction()->getEntryBlock();
5507 NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
5508 }
5509 IRBuilder<> NewBaseBuilder(NewBaseInsertBB, NewBaseInsertPt);
5510 // Create a new base.
5511 Value *BaseIndex = ConstantInt::get(IntPtrTy, BaseOffset);
5512 NewBaseGEP = OldBase;
5513 if (NewBaseGEP->getType() != I8PtrTy)
5514 NewBaseGEP = NewBaseBuilder.CreatePointerCast(NewBaseGEP, I8PtrTy);
5515 NewBaseGEP =
5516 NewBaseBuilder.CreateGEP(I8Ty, NewBaseGEP, BaseIndex, "splitgep");
5517 NewGEPBases.insert(NewBaseGEP);
5518 }
5519
5520 IRBuilder<> Builder(GEP);
5521 Value *NewGEP = NewBaseGEP;
5522 if (Offset == BaseOffset) {
5523 if (GEP->getType() != I8PtrTy)
5524 NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType());
5525 } else {
5526 // Calculate the new offset for the new GEP.
5527 Value *Index = ConstantInt::get(IntPtrTy, Offset - BaseOffset);
5528 NewGEP = Builder.CreateGEP(I8Ty, NewBaseGEP, Index);
5529
5530 if (GEP->getType() != I8PtrTy)
5531 NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType());
5532 }
5533 GEP->replaceAllUsesWith(NewGEP);
5534 LargeOffsetGEPID.erase(GEP);
5535 LargeOffsetGEP = LargeOffsetGEPs.erase(LargeOffsetGEP);
5536 GEP->eraseFromParent();
5537 Changed = true;
5538 }
5539 }
5540 return Changed;
5541}
5542
5543/// Return true, if an ext(load) can be formed from an extension in
5544/// \p MovedExts.
5545bool CodeGenPrepare::canFormExtLd(
5546 const SmallVectorImpl<Instruction *> &MovedExts, LoadInst *&LI,
5547 Instruction *&Inst, bool HasPromoted) {
5548 for (auto *MovedExtInst : MovedExts) {
5549 if (isa<LoadInst>(MovedExtInst->getOperand(0))) {
5550 LI = cast<LoadInst>(MovedExtInst->getOperand(0));
5551 Inst = MovedExtInst;
5552 break;
5553 }
5554 }
5555 if (!LI)
5556 return false;
5557
5558 // If they're already in the same block, there's nothing to do.
5559 // Make the cheap checks first if we did not promote.
5560 // If we promoted, we need to check if it is indeed profitable.
5561 if (!HasPromoted && LI->getParent() == Inst->getParent())
5562 return false;
5563
5564 return TLI->isExtLoad(LI, Inst, *DL);
5565}
5566
5567/// Move a zext or sext fed by a load into the same basic block as the load,
5568/// unless conditions are unfavorable. This allows SelectionDAG to fold the
5569/// extend into the load.
5570///
5571/// E.g.,
5572/// \code
5573/// %ld = load i32* %addr
5574/// %add = add nuw i32 %ld, 4
5575/// %zext = zext i32 %add to i64
5576// \endcode
5577/// =>
5578/// \code
5579/// %ld = load i32* %addr
5580/// %zext = zext i32 %ld to i64
5581/// %add = add nuw i64 %zext, 4
5582/// \encode
5583/// Note that the promotion in %add to i64 is done in tryToPromoteExts(), which
5584/// allow us to match zext(load i32*) to i64.
5585///
5586/// Also, try to promote the computations used to obtain a sign extended
5587/// value used into memory accesses.
5588/// E.g.,
5589/// \code
5590/// a = add nsw i32 b, 3
5591/// d = sext i32 a to i64
5592/// e = getelementptr ..., i64 d
5593/// \endcode
5594/// =>
5595/// \code
5596/// f = sext i32 b to i64
5597/// a = add nsw i64 f, 3
5598/// e = getelementptr ..., i64 a
5599/// \endcode
5600///
5601/// \p Inst[in/out] the extension may be modified during the process if some
5602/// promotions apply.
5603bool CodeGenPrepare::optimizeExt(Instruction *&Inst) {
5604 bool AllowPromotionWithoutCommonHeader = false;
5605 /// See if it is an interesting sext operations for the address type
5606 /// promotion before trying to promote it, e.g., the ones with the right
5607 /// type and used in memory accesses.
5608 bool ATPConsiderable = TTI->shouldConsiderAddressTypePromotion(
5609 *Inst, AllowPromotionWithoutCommonHeader);
5610 TypePromotionTransaction TPT(RemovedInsts);
5611 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
5612 TPT.getRestorationPoint();
5613 SmallVector<Instruction *, 1> Exts;
5614 SmallVector<Instruction *, 2> SpeculativelyMovedExts;
5615 Exts.push_back(Inst);
5616
5617 bool HasPromoted = tryToPromoteExts(TPT, Exts, SpeculativelyMovedExts);
5618
5619 // Look for a load being extended.
5620 LoadInst *LI = nullptr;
5621 Instruction *ExtFedByLoad;
5622
5623 // Try to promote a chain of computation if it allows to form an extended
5624 // load.
5625 if (canFormExtLd(SpeculativelyMovedExts, LI, ExtFedByLoad, HasPromoted)) {
5626 assert(LI && ExtFedByLoad && "Expect a valid load and extension")((LI && ExtFedByLoad && "Expect a valid load and extension"
) ? static_cast<void> (0) : __assert_fail ("LI && ExtFedByLoad && \"Expect a valid load and extension\""
, "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5626, __PRETTY_FUNCTION__))
;
5627 TPT.commit();
5628 // Move the extend into the same block as the load
5629 ExtFedByLoad->moveAfter(LI);
5630 // CGP does not check if the zext would be speculatively executed when moved
5631 // to the same basic block as the load. Preserving its original location
5632 // would pessimize the debugging experience, as well as negatively impact
5633 // the quality of sample pgo. We don't want to use "line 0" as that has a
5634 // size cost in the line-table section and logically the zext can be seen as
5635 // part of the load. Therefore we conservatively reuse the same debug
5636 // location for the load and the zext.
5637 ExtFedByLoad->setDebugLoc(LI->getDebugLoc());
5638 ++NumExtsMoved;
5639 Inst = ExtFedByLoad;
5640 return true;
5641 }
5642
5643 // Continue promoting SExts if known as considerable depending on targets.
5644 if (ATPConsiderable &&
5645 performAddressTypePromotion(Inst, AllowPromotionWithoutCommonHeader,
5646 HasPromoted, TPT, SpeculativelyMovedExts))
5647 return true;
5648
5649 TPT.rollback(LastKnownGood);
5650 return false;
5651}
5652
5653// Perform address type promotion if doing so is profitable.
5654// If AllowPromotionWithoutCommonHeader == false, we should find other sext
5655// instructions that sign extended the same initial value. However, if
5656// AllowPromotionWithoutCommonHeader == true, we expect promoting the
5657// extension is just profitable.
5658bool CodeGenPrepare::performAddressTypePromotion(
5659 Instruction *&Inst, bool AllowPromotionWithoutCommonHeader,
5660 bool HasPromoted, TypePromotionTransaction &TPT,
5661 SmallVectorImpl<Instruction *> &SpeculativelyMovedExts) {
5662 bool Promoted = false;
5663 SmallPtrSet<Instruction *, 1> UnhandledExts;
5664 bool AllSeenFirst = true;
5665 for (auto I : SpeculativelyMovedExts) {
5666 Value *HeadOfChain = I->getOperand(0);
5667 DenseMap<Value *, Instruction *>::iterator AlreadySeen =
5668 SeenChainsForSExt.find(HeadOfChain);
5669 // If there is an unhandled SExt which has the same header, try to promote
5670 // it as well.
5671 if (AlreadySeen != SeenChainsForSExt.end()) {
5672 if (AlreadySeen->second != nullptr)
5673 UnhandledExts.insert(AlreadySeen->second);
5674 AllSeenFirst = false;
5675 }
5676 }
5677
5678 if (!AllSeenFirst || (AllowPromotionWithoutCommonHeader &&
5679 SpeculativelyMovedExts.size() == 1)) {
5680 TPT.commit();
5681 if (HasPromoted)
5682 Promoted = true;
5683 for (auto I : SpeculativelyMovedExts) {
5684 Value *HeadOfChain = I->getOperand(0);
5685 SeenChainsForSExt[HeadOfChain] = nullptr;
5686 ValToSExtendedUses[HeadOfChain].push_back(I);
5687 }
5688 // Update Inst as promotion happen.
5689 Inst = SpeculativelyMovedExts.pop_back_val();
5690 } else {
5691 // This is the first chain visited from the header, keep the current chain
5692 // as unhandled. Defer to promote this until we encounter another SExt
5693 // chain derived from the same header.
5694 for (auto I : SpeculativelyMovedExts) {
5695 Value *HeadOfChain = I->getOperand(0);
5696 SeenChainsForSExt[HeadOfChain] = Inst;
5697 }
5698 return false;
5699 }
5700
5701 if (!AllSeenFirst && !UnhandledExts.empty())
5702 for (auto VisitedSExt : UnhandledExts) {
5703 if (RemovedInsts.count(VisitedSExt))
5704 continue;
5705 TypePromotionTransaction TPT(RemovedInsts);
5706 SmallVector<Instruction *, 1> Exts;
5707 SmallVector<Instruction *, 2> Chains;
5708 Exts.push_back(VisitedSExt);
5709 bool HasPromoted = tryToPromoteExts(TPT, Exts, Chains);
5710 TPT.commit();
5711 if (HasPromoted)
5712 Promoted = true;
5713 for (auto I : Chains) {
5714 Value *HeadOfChain = I->getOperand(0);
5715 // Mark this as handled.
5716 SeenChainsForSExt[HeadOfChain] = nullptr;
5717 ValToSExtendedUses[HeadOfChain].push_back(I);
5718 }
5719 }
5720 return Promoted;
5721}
5722
5723bool CodeGenPrepare::optimizeExtUses(Instruction *I) {
5724 BasicBlock *DefBB = I->getParent();
5725
5726 // If the result of a {s|z}ext and its source are both live out, rewrite all
5727 // other uses of the source with result of extension.
5728 Value *Src = I->getOperand(0);
5729 if (Src->hasOneUse())
5730 return false;
5731
5732 // Only do this xform if truncating is free.
5733 if (!TLI->isTruncateFree(I->getType(), Src->getType()))
5734 return false;
5735
5736 // Only safe to perform the optimization if the source is also defined in
5737 // this block.
5738 if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
5739 return false;
5740
5741 bool DefIsLiveOut = false;
5742 for (User *U : I->users()) {
5743 Instruction *UI = cast<Instruction>(U);
5744
5745 // Figure out which BB this ext is used in.
5746 BasicBlock *UserBB = UI->getParent();
5747 if (UserBB == DefBB) continue;
5748 DefIsLiveOut = true;
5749 break;
5750 }
5751 if (!DefIsLiveOut)
5752 return false;
5753
5754 // Make sure none of the uses are PHI nodes.
5755 for (User *U : Src->users()) {
5756 Instruction *UI = cast<Instruction>(U);
5757 BasicBlock *UserBB = UI->getParent();
5758 if (UserBB == DefBB) continue;
5759 // Be conservative. We don't want this xform to end up introducing
5760 // reloads just before load / store instructions.
5761 if (isa<PHINode>(UI) || isa<LoadInst>(UI) || isa<StoreInst>(UI))
5762 return false;
5763 }
5764
5765 // InsertedTruncs - Only insert one trunc in each block once.
5766 DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
5767
5768 bool MadeChange = false;
5769 for (Use &U : Src->uses()) {
5770 Instruction *User = cast<Instruction>(U.getUser());
5771
5772 // Figure out which BB this ext is used in.
5773 BasicBlock *UserBB = User->getParent();
5774 if (UserBB == DefBB) continue;
5775
5776 // Both src and def are live in this block. Rewrite the use.
5777 Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
5778
5779 if (!InsertedTrunc) {
5780 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
5781 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5781, __PRETTY_FUNCTION__))
;
5782 InsertedTrunc = new TruncInst(I, Src->getType(), "", &*InsertPt);
5783 InsertedInsts.insert(InsertedTrunc);
5784 }
5785
5786 // Replace a use of the {s|z}ext source with a use of the result.
5787 U = InsertedTrunc;
5788 ++NumExtUses;
5789 MadeChange = true;
5790 }
5791
5792 return MadeChange;
5793}
5794
5795// Find loads whose uses only use some of the loaded value's bits. Add an "and"
5796// just after the load if the target can fold this into one extload instruction,
5797// with the hope of eliminating some of the other later "and" instructions using
5798// the loaded value. "and"s that are made trivially redundant by the insertion
5799// of the new "and" are removed by this function, while others (e.g. those whose
5800// path from the load goes through a phi) are left for isel to potentially
5801// remove.
5802//
5803// For example:
5804//
5805// b0:
5806// x = load i32
5807// ...
5808// b1:
5809// y = and x, 0xff
5810// z = use y
5811//
5812// becomes:
5813//
5814// b0:
5815// x = load i32
5816// x' = and x, 0xff
5817// ...
5818// b1:
5819// z = use x'
5820//
5821// whereas:
5822//
5823// b0:
5824// x1 = load i32
5825// ...
5826// b1:
5827// x2 = load i