Bug Summary

File:llvm/lib/CodeGen/CodeGenPrepare.cpp
Warning:line 1014, 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-10/lib/clang/10.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/build-llvm/include -I /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/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-10/lib/clang/10.0.0/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-10~++20200112100611+7fa5290d5bd/build-llvm/lib/CodeGen -fdebug-prefix-map=/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd=. -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-2020-01-13-084841-49055-1 -x c++ /build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/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<TargetTransformInfoWrapperPass>();
331 AU.addRequired<LoopInfoWrapperPass>();
332 }
333
334 private:
335 template <typename F>
336 void resetIteratorIfInvalidatedWhileCalling(BasicBlock *BB, F f) {
337 // Substituting can cause recursive simplifications, which can invalidate
338 // our iterator. Use a WeakTrackingVH to hold onto it in case this
339 // happens.
340 Value *CurValue = &*CurInstIterator;
341 WeakTrackingVH IterHandle(CurValue);
342
343 f();
344
345 // If the iterator instruction was recursively deleted, start over at the
346 // start of the block.
347 if (IterHandle != CurValue) {
348 CurInstIterator = BB->begin();
349 SunkAddrs.clear();
350 }
351 }
352
353 // Get the DominatorTree, building if necessary.
354 DominatorTree &getDT(Function &F) {
355 if (!DT)
356 DT = std::make_unique<DominatorTree>(F);
357 return *DT;
358 }
359
360 bool eliminateFallThrough(Function &F);
361 bool eliminateMostlyEmptyBlocks(Function &F);
362 BasicBlock *findDestBlockOfMergeableEmptyBlock(BasicBlock *BB);
363 bool canMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
364 void eliminateMostlyEmptyBlock(BasicBlock *BB);
365 bool isMergingEmptyBlockProfitable(BasicBlock *BB, BasicBlock *DestBB,
366 bool isPreheader);
367 bool optimizeBlock(BasicBlock &BB, bool &ModifiedDT);
368 bool optimizeInst(Instruction *I, bool &ModifiedDT);
369 bool optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
370 Type *AccessTy, unsigned AddrSpace);
371 bool optimizeInlineAsmInst(CallInst *CS);
372 bool optimizeCallInst(CallInst *CI, bool &ModifiedDT);
373 bool optimizeExt(Instruction *&I);
374 bool optimizeExtUses(Instruction *I);
375 bool optimizeLoadExt(LoadInst *Load);
376 bool optimizeShiftInst(BinaryOperator *BO);
377 bool optimizeSelectInst(SelectInst *SI);
378 bool optimizeShuffleVectorInst(ShuffleVectorInst *SVI);
379 bool optimizeSwitchInst(SwitchInst *SI);
380 bool optimizeExtractElementInst(Instruction *Inst);
381 bool dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT);
382 bool fixupDbgValue(Instruction *I);
383 bool placeDbgValues(Function &F);
384 bool canFormExtLd(const SmallVectorImpl<Instruction *> &MovedExts,
385 LoadInst *&LI, Instruction *&Inst, bool HasPromoted);
386 bool tryToPromoteExts(TypePromotionTransaction &TPT,
387 const SmallVectorImpl<Instruction *> &Exts,
388 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
389 unsigned CreatedInstsCost = 0);
390 bool mergeSExts(Function &F);
391 bool splitLargeGEPOffsets();
392 bool performAddressTypePromotion(
393 Instruction *&Inst,
394 bool AllowPromotionWithoutCommonHeader,
395 bool HasPromoted, TypePromotionTransaction &TPT,
396 SmallVectorImpl<Instruction *> &SpeculativelyMovedExts);
397 bool splitBranchCondition(Function &F, bool &ModifiedDT);
398 bool simplifyOffsetableRelocate(Instruction &I);
399
400 bool tryToSinkFreeOperands(Instruction *I);
401 bool replaceMathCmpWithIntrinsic(BinaryOperator *BO, CmpInst *Cmp,
402 Intrinsic::ID IID);
403 bool optimizeCmp(CmpInst *Cmp, bool &ModifiedDT);
404 bool combineToUSubWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
405 bool combineToUAddWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
406 };
407
408} // end anonymous namespace
409
410char CodeGenPrepare::ID = 0;
411
412INITIALIZE_PASS_BEGIN(CodeGenPrepare, DEBUG_TYPE,static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
413 "Optimize for code generation", false, false)static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
414INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)initializeProfileSummaryInfoWrapperPassPass(Registry);
415INITIALIZE_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)); }
416 "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)); }
417
418FunctionPass *llvm::createCodeGenPreparePass() { return new CodeGenPrepare(); }
419
420bool CodeGenPrepare::runOnFunction(Function &F) {
421 if (skipFunction(F))
422 return false;
423
424 DL = &F.getParent()->getDataLayout();
425
426 bool EverMadeChange = false;
427 // Clear per function information.
428 InsertedInsts.clear();
429 PromotedInsts.clear();
430
431 if (auto *TPC = getAnalysisIfAvailable<TargetPassConfig>()) {
432 TM = &TPC->getTM<TargetMachine>();
433 SubtargetInfo = TM->getSubtargetImpl(F);
434 TLI = SubtargetInfo->getTargetLowering();
435 TRI = SubtargetInfo->getRegisterInfo();
436 }
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 &&
454 TLI->isSlowDivBypassed()) {
455 const DenseMap<unsigned int, unsigned int> &BypassWidths =
456 TLI->getBypassSlowDivWidths();
457 BasicBlock* BB = &*F.begin();
458 while (BB != nullptr) {
459 // bypassSlowDivision may create new BBs, but we don't want to reapply the
460 // optimization to those blocks.
461 BasicBlock* Next = BB->getNextNode();
462 // F.hasOptSize is already checked in the outer if statement.
463 if (!llvm::shouldOptimizeForSize(BB, PSI, BFI.get()))
464 EverMadeChange |= bypassSlowDivision(BB, BypassWidths);
465 BB = Next;
466 }
467 }
468
469 // Eliminate blocks that contain only PHI nodes and an
470 // unconditional branch.
471 EverMadeChange |= eliminateMostlyEmptyBlocks(F);
472
473 bool ModifiedDT = false;
474 if (!DisableBranchOpts)
475 EverMadeChange |= splitBranchCondition(F, ModifiedDT);
476
477 // Split some critical edges where one of the sources is an indirect branch,
478 // to help generate sane code for PHIs involving such edges.
479 EverMadeChange |= SplitIndirectBrCriticalEdges(F);
480
481 bool MadeChange = true;
482 while (MadeChange) {
483 MadeChange = false;
484 DT.reset();
485 for (Function::iterator I = F.begin(); I != F.end(); ) {
486 BasicBlock *BB = &*I++;
487 bool ModifiedDTOnIteration = false;
488 MadeChange |= optimizeBlock(*BB, ModifiedDTOnIteration);
489
490 // Restart BB iteration if the dominator tree of the Function was changed
491 if (ModifiedDTOnIteration)
492 break;
493 }
494 if (EnableTypePromotionMerge && !ValToSExtendedUses.empty())
495 MadeChange |= mergeSExts(F);
496 if (!LargeOffsetGEPMap.empty())
497 MadeChange |= splitLargeGEPOffsets();
498
499 // Really free removed instructions during promotion.
500 for (Instruction *I : RemovedInsts)
501 I->deleteValue();
502
503 EverMadeChange |= MadeChange;
504 SeenChainsForSExt.clear();
505 ValToSExtendedUses.clear();
506 RemovedInsts.clear();
507 LargeOffsetGEPMap.clear();
508 LargeOffsetGEPID.clear();
509 }
510
511 SunkAddrs.clear();
512
513 if (!DisableBranchOpts) {
514 MadeChange = false;
515 // Use a set vector to get deterministic iteration order. The order the
516 // blocks are removed may affect whether or not PHI nodes in successors
517 // are removed.
518 SmallSetVector<BasicBlock*, 8> WorkList;
519 for (BasicBlock &BB : F) {
520 SmallVector<BasicBlock *, 2> Successors(succ_begin(&BB), succ_end(&BB));
521 MadeChange |= ConstantFoldTerminator(&BB, true);
522 if (!MadeChange) continue;
523
524 for (SmallVectorImpl<BasicBlock*>::iterator
525 II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
526 if (pred_begin(*II) == pred_end(*II))
527 WorkList.insert(*II);
528 }
529
530 // Delete the dead blocks and any of their dead successors.
531 MadeChange |= !WorkList.empty();
532 while (!WorkList.empty()) {
533 BasicBlock *BB = WorkList.pop_back_val();
534 SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
535
536 DeleteDeadBlock(BB);
537
538 for (SmallVectorImpl<BasicBlock*>::iterator
539 II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
540 if (pred_begin(*II) == pred_end(*II))
541 WorkList.insert(*II);
542 }
543
544 // Merge pairs of basic blocks with unconditional branches, connected by
545 // a single edge.
546 if (EverMadeChange || MadeChange)
547 MadeChange |= eliminateFallThrough(F);
548
549 EverMadeChange |= MadeChange;
550 }
551
552 if (!DisableGCOpts) {
553 SmallVector<Instruction *, 2> Statepoints;
554 for (BasicBlock &BB : F)
555 for (Instruction &I : BB)
556 if (isStatepoint(I))
557 Statepoints.push_back(&I);
558 for (auto &I : Statepoints)
559 EverMadeChange |= simplifyOffsetableRelocate(*I);
560 }
561
562 // Do this last to clean up use-before-def scenarios introduced by other
563 // preparatory transforms.
564 EverMadeChange |= placeDbgValues(F);
565
566 return EverMadeChange;
567}
568
569/// Merge basic blocks which are connected by a single edge, where one of the
570/// basic blocks has a single successor pointing to the other basic block,
571/// which has a single predecessor.
572bool CodeGenPrepare::eliminateFallThrough(Function &F) {
573 bool Changed = false;
574 // Scan all of the blocks in the function, except for the entry block.
575 // Use a temporary array to avoid iterator being invalidated when
576 // deleting blocks.
577 SmallVector<WeakTrackingVH, 16> Blocks;
578 for (auto &Block : llvm::make_range(std::next(F.begin()), F.end()))
579 Blocks.push_back(&Block);
580
581 for (auto &Block : Blocks) {
582 auto *BB = cast_or_null<BasicBlock>(Block);
583 if (!BB)
584 continue;
585 // If the destination block has a single pred, then this is a trivial
586 // edge, just collapse it.
587 BasicBlock *SinglePred = BB->getSinglePredecessor();
588
589 // Don't merge if BB's address is taken.
590 if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue;
591
592 BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
593 if (Term && !Term->isConditional()) {
594 Changed = true;
595 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)
;
596
597 // Merge BB into SinglePred and delete it.
598 MergeBlockIntoPredecessor(BB);
599 }
600 }
601 return Changed;
602}
603
604/// Find a destination block from BB if BB is mergeable empty block.
605BasicBlock *CodeGenPrepare::findDestBlockOfMergeableEmptyBlock(BasicBlock *BB) {
606 // If this block doesn't end with an uncond branch, ignore it.
607 BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
608 if (!BI || !BI->isUnconditional())
609 return nullptr;
610
611 // If the instruction before the branch (skipping debug info) isn't a phi
612 // node, then other stuff is happening here.
613 BasicBlock::iterator BBI = BI->getIterator();
614 if (BBI != BB->begin()) {
615 --BBI;
616 while (isa<DbgInfoIntrinsic>(BBI)) {
617 if (BBI == BB->begin())
618 break;
619 --BBI;
620 }
621 if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI))
622 return nullptr;
623 }
624
625 // Do not break infinite loops.
626 BasicBlock *DestBB = BI->getSuccessor(0);
627 if (DestBB == BB)
628 return nullptr;
629
630 if (!canMergeBlocks(BB, DestBB))
631 DestBB = nullptr;
632
633 return DestBB;
634}
635
636/// Eliminate blocks that contain only PHI nodes, debug info directives, and an
637/// unconditional branch. Passes before isel (e.g. LSR/loopsimplify) often split
638/// edges in ways that are non-optimal for isel. Start by eliminating these
639/// blocks so we can split them the way we want them.
640bool CodeGenPrepare::eliminateMostlyEmptyBlocks(Function &F) {
641 SmallPtrSet<BasicBlock *, 16> Preheaders;
642 SmallVector<Loop *, 16> LoopList(LI->begin(), LI->end());
643 while (!LoopList.empty()) {
644 Loop *L = LoopList.pop_back_val();
645 LoopList.insert(LoopList.end(), L->begin(), L->end());
646 if (BasicBlock *Preheader = L->getLoopPreheader())
647 Preheaders.insert(Preheader);
648 }
649
650 bool MadeChange = false;
651 // Copy blocks into a temporary array to avoid iterator invalidation issues
652 // as we remove them.
653 // Note that this intentionally skips the entry block.
654 SmallVector<WeakTrackingVH, 16> Blocks;
655 for (auto &Block : llvm::make_range(std::next(F.begin()), F.end()))
656 Blocks.push_back(&Block);
657
658 for (auto &Block : Blocks) {
659 BasicBlock *BB = cast_or_null<BasicBlock>(Block);
660 if (!BB)
661 continue;
662 BasicBlock *DestBB = findDestBlockOfMergeableEmptyBlock(BB);
663 if (!DestBB ||
664 !isMergingEmptyBlockProfitable(BB, DestBB, Preheaders.count(BB)))
665 continue;
666
667 eliminateMostlyEmptyBlock(BB);
668 MadeChange = true;
669 }
670 return MadeChange;
671}
672
673bool CodeGenPrepare::isMergingEmptyBlockProfitable(BasicBlock *BB,
674 BasicBlock *DestBB,
675 bool isPreheader) {
676 // Do not delete loop preheaders if doing so would create a critical edge.
677 // Loop preheaders can be good locations to spill registers. If the
678 // preheader is deleted and we create a critical edge, registers may be
679 // spilled in the loop body instead.
680 if (!DisablePreheaderProtect && isPreheader &&
681 !(BB->getSinglePredecessor() &&
682 BB->getSinglePredecessor()->getSingleSuccessor()))
683 return false;
684
685 // Skip merging if the block's successor is also a successor to any callbr
686 // that leads to this block.
687 // FIXME: Is this really needed? Is this a correctness issue?
688 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
689 if (auto *CBI = dyn_cast<CallBrInst>((*PI)->getTerminator()))
690 for (unsigned i = 0, e = CBI->getNumSuccessors(); i != e; ++i)
691 if (DestBB == CBI->getSuccessor(i))
692 return false;
693 }
694
695 // Try to skip merging if the unique predecessor of BB is terminated by a
696 // switch or indirect branch instruction, and BB is used as an incoming block
697 // of PHIs in DestBB. In such case, merging BB and DestBB would cause ISel to
698 // add COPY instructions in the predecessor of BB instead of BB (if it is not
699 // merged). Note that the critical edge created by merging such blocks wont be
700 // split in MachineSink because the jump table is not analyzable. By keeping
701 // such empty block (BB), ISel will place COPY instructions in BB, not in the
702 // predecessor of BB.
703 BasicBlock *Pred = BB->getUniquePredecessor();
704 if (!Pred ||
705 !(isa<SwitchInst>(Pred->getTerminator()) ||
706 isa<IndirectBrInst>(Pred->getTerminator())))
707 return true;
708
709 if (BB->getTerminator() != BB->getFirstNonPHIOrDbg())
710 return true;
711
712 // We use a simple cost heuristic which determine skipping merging is
713 // profitable if the cost of skipping merging is less than the cost of
714 // merging : Cost(skipping merging) < Cost(merging BB), where the
715 // Cost(skipping merging) is Freq(BB) * (Cost(Copy) + Cost(Branch)), and
716 // the Cost(merging BB) is Freq(Pred) * Cost(Copy).
717 // Assuming Cost(Copy) == Cost(Branch), we could simplify it to :
718 // Freq(Pred) / Freq(BB) > 2.
719 // Note that if there are multiple empty blocks sharing the same incoming
720 // value for the PHIs in the DestBB, we consider them together. In such
721 // case, Cost(merging BB) will be the sum of their frequencies.
722
723 if (!isa<PHINode>(DestBB->begin()))
724 return true;
725
726 SmallPtrSet<BasicBlock *, 16> SameIncomingValueBBs;
727
728 // Find all other incoming blocks from which incoming values of all PHIs in
729 // DestBB are the same as the ones from BB.
730 for (pred_iterator PI = pred_begin(DestBB), E = pred_end(DestBB); PI != E;
731 ++PI) {
732 BasicBlock *DestBBPred = *PI;
733 if (DestBBPred == BB)
734 continue;
735
736 if (llvm::all_of(DestBB->phis(), [&](const PHINode &DestPN) {
737 return DestPN.getIncomingValueForBlock(BB) ==
738 DestPN.getIncomingValueForBlock(DestBBPred);
739 }))
740 SameIncomingValueBBs.insert(DestBBPred);
741 }
742
743 // See if all BB's incoming values are same as the value from Pred. In this
744 // case, no reason to skip merging because COPYs are expected to be place in
745 // Pred already.
746 if (SameIncomingValueBBs.count(Pred))
747 return true;
748
749 BlockFrequency PredFreq = BFI->getBlockFreq(Pred);
750 BlockFrequency BBFreq = BFI->getBlockFreq(BB);
751
752 for (auto SameValueBB : SameIncomingValueBBs)
753 if (SameValueBB->getUniquePredecessor() == Pred &&
754 DestBB == findDestBlockOfMergeableEmptyBlock(SameValueBB))
755 BBFreq += BFI->getBlockFreq(SameValueBB);
756
757 return PredFreq.getFrequency() <=
758 BBFreq.getFrequency() * FreqRatioToSkipMerge;
759}
760
761/// Return true if we can merge BB into DestBB if there is a single
762/// unconditional branch between them, and BB contains no other non-phi
763/// instructions.
764bool CodeGenPrepare::canMergeBlocks(const BasicBlock *BB,
765 const BasicBlock *DestBB) const {
766 // We only want to eliminate blocks whose phi nodes are used by phi nodes in
767 // the successor. If there are more complex condition (e.g. preheaders),
768 // don't mess around with them.
769 for (const PHINode &PN : BB->phis()) {
770 for (const User *U : PN.users()) {
771 const Instruction *UI = cast<Instruction>(U);
772 if (UI->getParent() != DestBB || !isa<PHINode>(UI))
773 return false;
774 // If User is inside DestBB block and it is a PHINode then check
775 // incoming value. If incoming value is not from BB then this is
776 // a complex condition (e.g. preheaders) we want to avoid here.
777 if (UI->getParent() == DestBB) {
778 if (const PHINode *UPN = dyn_cast<PHINode>(UI))
779 for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
780 Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
781 if (Insn && Insn->getParent() == BB &&
782 Insn->getParent() != UPN->getIncomingBlock(I))
783 return false;
784 }
785 }
786 }
787 }
788
789 // If BB and DestBB contain any common predecessors, then the phi nodes in BB
790 // and DestBB may have conflicting incoming values for the block. If so, we
791 // can't merge the block.
792 const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
793 if (!DestBBPN) return true; // no conflict.
794
795 // Collect the preds of BB.
796 SmallPtrSet<const BasicBlock*, 16> BBPreds;
797 if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
798 // It is faster to get preds from a PHI than with pred_iterator.
799 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
800 BBPreds.insert(BBPN->getIncomingBlock(i));
801 } else {
802 BBPreds.insert(pred_begin(BB), pred_end(BB));
803 }
804
805 // Walk the preds of DestBB.
806 for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
807 BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
808 if (BBPreds.count(Pred)) { // Common predecessor?
809 for (const PHINode &PN : DestBB->phis()) {
810 const Value *V1 = PN.getIncomingValueForBlock(Pred);
811 const Value *V2 = PN.getIncomingValueForBlock(BB);
812
813 // If V2 is a phi node in BB, look up what the mapped value will be.
814 if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
815 if (V2PN->getParent() == BB)
816 V2 = V2PN->getIncomingValueForBlock(Pred);
817
818 // If there is a conflict, bail out.
819 if (V1 != V2) return false;
820 }
821 }
822 }
823
824 return true;
825}
826
827/// Eliminate a basic block that has only phi's and an unconditional branch in
828/// it.
829void CodeGenPrepare::eliminateMostlyEmptyBlock(BasicBlock *BB) {
830 BranchInst *BI = cast<BranchInst>(BB->getTerminator());
831 BasicBlock *DestBB = BI->getSuccessor(0);
832
833 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)
834 << *BB << *DestBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"
<< *BB << *DestBB; } } while (false)
;
835
836 // If the destination block has a single pred, then this is a trivial edge,
837 // just collapse it.
838 if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
839 if (SinglePred != DestBB) {
840 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 841, __PRETTY_FUNCTION__))
841 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 841, __PRETTY_FUNCTION__))
;
842 // Merge DestBB into SinglePred/BB and delete it.
843 MergeBlockIntoPredecessor(DestBB);
844 // Note: BB(=SinglePred) will not be deleted on this path.
845 // DestBB(=its single successor) is the one that was deleted.
846 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)
;
847 return;
848 }
849 }
850
851 // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
852 // to handle the new incoming edges it is about to have.
853 for (PHINode &PN : DestBB->phis()) {
854 // Remove the incoming value for BB, and remember it.
855 Value *InVal = PN.removeIncomingValue(BB, false);
856
857 // Two options: either the InVal is a phi node defined in BB or it is some
858 // value that dominates BB.
859 PHINode *InValPhi = dyn_cast<PHINode>(InVal);
860 if (InValPhi && InValPhi->getParent() == BB) {
861 // Add all of the input values of the input PHI as inputs of this phi.
862 for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
863 PN.addIncoming(InValPhi->getIncomingValue(i),
864 InValPhi->getIncomingBlock(i));
865 } else {
866 // Otherwise, add one instance of the dominating value for each edge that
867 // we will be adding.
868 if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
869 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
870 PN.addIncoming(InVal, BBPN->getIncomingBlock(i));
871 } else {
872 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
873 PN.addIncoming(InVal, *PI);
874 }
875 }
876 }
877
878 // The PHIs are now updated, change everything that refers to BB to use
879 // DestBB and remove BB.
880 BB->replaceAllUsesWith(DestBB);
881 BB->eraseFromParent();
882 ++NumBlocksElim;
883
884 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)
;
885}
886
887// Computes a map of base pointer relocation instructions to corresponding
888// derived pointer relocation instructions given a vector of all relocate calls
889static void computeBaseDerivedRelocateMap(
890 const SmallVectorImpl<GCRelocateInst *> &AllRelocateCalls,
891 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>>
892 &RelocateInstMap) {
893 // Collect information in two maps: one primarily for locating the base object
894 // while filling the second map; the second map is the final structure holding
895 // a mapping between Base and corresponding Derived relocate calls
896 DenseMap<std::pair<unsigned, unsigned>, GCRelocateInst *> RelocateIdxMap;
897 for (auto *ThisRelocate : AllRelocateCalls) {
898 auto K = std::make_pair(ThisRelocate->getBasePtrIndex(),
899 ThisRelocate->getDerivedPtrIndex());
900 RelocateIdxMap.insert(std::make_pair(K, ThisRelocate));
901 }
902 for (auto &Item : RelocateIdxMap) {
903 std::pair<unsigned, unsigned> Key = Item.first;
904 if (Key.first == Key.second)
905 // Base relocation: nothing to insert
906 continue;
907
908 GCRelocateInst *I = Item.second;
909 auto BaseKey = std::make_pair(Key.first, Key.first);
910
911 // We're iterating over RelocateIdxMap so we cannot modify it.
912 auto MaybeBase = RelocateIdxMap.find(BaseKey);
913 if (MaybeBase == RelocateIdxMap.end())
914 // TODO: We might want to insert a new base object relocate and gep off
915 // that, if there are enough derived object relocates.
916 continue;
917
918 RelocateInstMap[MaybeBase->second].push_back(I);
919 }
920}
921
922// Accepts a GEP and extracts the operands into a vector provided they're all
923// small integer constants
924static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
925 SmallVectorImpl<Value *> &OffsetV) {
926 for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
20
Assuming the condition is false
21
Loop condition is false. Execution continues on line 933
927 // Only accept small constant integer operands
928 auto Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
929 if (!Op || Op->getZExtValue() > 20)
930 return false;
931 }
932
933 for (unsigned i = 1; i < GEP->getNumOperands(); i++)
22
Loop condition is false. Execution continues on line 935
934 OffsetV.push_back(GEP->getOperand(i));
935 return true;
23
Returning the value 1, which participates in a condition later
936}
937
938// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
939// replace, computes a replacement, and affects it.
940static bool
941simplifyRelocatesOffABase(GCRelocateInst *RelocatedBase,
942 const SmallVectorImpl<GCRelocateInst *> &Targets) {
943 bool MadeChange = false;
944 // We must ensure the relocation of derived pointer is defined after
945 // relocation of base pointer. If we find a relocation corresponding to base
946 // defined earlier than relocation of base then we move relocation of base
947 // right before found relocation. We consider only relocation in the same
948 // basic block as relocation of base. Relocations from other basic block will
949 // be skipped by optimization and we do not care about them.
950 for (auto R = RelocatedBase->getParent()->getFirstInsertionPt();
7
Loop condition is false. Execution continues on line 959
951 &*R != RelocatedBase; ++R)
6
Assuming the condition is false
952 if (auto RI = dyn_cast<GCRelocateInst>(R))
953 if (RI->getStatepoint() == RelocatedBase->getStatepoint())
954 if (RI->getBasePtrIndex() == RelocatedBase->getBasePtrIndex()) {
955 RelocatedBase->moveBefore(RI);
956 break;
957 }
958
959 for (GCRelocateInst *ToReplace : Targets) {
8
Assuming '__begin1' is not equal to '__end1'
960 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 961, __PRETTY_FUNCTION__))
9
Assuming the condition is true
10
'?' condition is true
961 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 961, __PRETTY_FUNCTION__))
;
962 if (ToReplace->getBasePtrIndex() == ToReplace->getDerivedPtrIndex()) {
11
Assuming the condition is false
12
Taking false branch
963 // A duplicate relocate call. TODO: coalesce duplicates.
964 continue;
965 }
966
967 if (RelocatedBase->getParent() != ToReplace->getParent()) {
13
Assuming the condition is false
14
Taking false branch
968 // Base and derived relocates are in different basic blocks.
969 // In this case transform is only valid when base dominates derived
970 // relocate. However it would be too expensive to check dominance
971 // for each such relocate, so we skip the whole transformation.
972 continue;
973 }
974
975 Value *Base = ToReplace->getBasePtr();
15
'Base' initialized here
976 auto Derived = dyn_cast<GetElementPtrInst>(ToReplace->getDerivedPtr());
16
Assuming the object is a 'GetElementPtrInst'
977 if (!Derived
16.1
'Derived' is non-null
|| Derived->getPointerOperand() != Base)
17
Assuming pointer value is null
18
Taking false branch
978 continue;
979
980 SmallVector<Value *, 2> OffsetV;
981 if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
19
Calling 'getGEPSmallConstantIntOffsetV'
24
Returning from 'getGEPSmallConstantIntOffsetV'
25
Taking false branch
982 continue;
983
984 // Create a Builder and replace the target callsite with a gep
985 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 986, __PRETTY_FUNCTION__))
26
Assuming the condition is true
27
'?' condition is true
986 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 986, __PRETTY_FUNCTION__))
;
987
988 // Insert after RelocatedBase
989 IRBuilder<> Builder(RelocatedBase->getNextNode());
990 Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
991
992 // If gc_relocate does not match the actual type, cast it to the right type.
993 // In theory, there must be a bitcast after gc_relocate if the type does not
994 // match, and we should reuse it to get the derived pointer. But it could be
995 // cases like this:
996 // bb1:
997 // ...
998 // %g1 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
999 // br label %merge
1000 //
1001 // bb2:
1002 // ...
1003 // %g2 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
1004 // br label %merge
1005 //
1006 // merge:
1007 // %p1 = phi i8 addrspace(1)* [ %g1, %bb1 ], [ %g2, %bb2 ]
1008 // %cast = bitcast i8 addrspace(1)* %p1 in to i32 addrspace(1)*
1009 //
1010 // In this case, we can not find the bitcast any more. So we insert a new bitcast
1011 // no matter there is already one or not. In this way, we can handle all cases, and
1012 // the extra bitcast should be optimized away in later passes.
1013 Value *ActualRelocatedBase = RelocatedBase;
1014 if (RelocatedBase->getType() != Base->getType()) {
28
Called C++ object pointer is null
1015 ActualRelocatedBase =
1016 Builder.CreateBitCast(RelocatedBase, Base->getType());
1017 }
1018 Value *Replacement = Builder.CreateGEP(
1019 Derived->getSourceElementType(), ActualRelocatedBase, makeArrayRef(OffsetV));
1020 Replacement->takeName(ToReplace);
1021 // If the newly generated derived pointer's type does not match the original derived
1022 // pointer's type, cast the new derived pointer to match it. Same reasoning as above.
1023 Value *ActualReplacement = Replacement;
1024 if (Replacement->getType() != ToReplace->getType()) {
1025 ActualReplacement =
1026 Builder.CreateBitCast(Replacement, ToReplace->getType());
1027 }
1028 ToReplace->replaceAllUsesWith(ActualReplacement);
1029 ToReplace->eraseFromParent();
1030
1031 MadeChange = true;
1032 }
1033 return MadeChange;
1034}
1035
1036// Turns this:
1037//
1038// %base = ...
1039// %ptr = gep %base + 15
1040// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1041// %base' = relocate(%tok, i32 4, i32 4)
1042// %ptr' = relocate(%tok, i32 4, i32 5)
1043// %val = load %ptr'
1044//
1045// into this:
1046//
1047// %base = ...
1048// %ptr = gep %base + 15
1049// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1050// %base' = gc.relocate(%tok, i32 4, i32 4)
1051// %ptr' = gep %base' + 15
1052// %val = load %ptr'
1053bool CodeGenPrepare::simplifyOffsetableRelocate(Instruction &I) {
1054 bool MadeChange = false;
1055 SmallVector<GCRelocateInst *, 2> AllRelocateCalls;
1056
1057 for (auto *U : I.users())
1058 if (GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U))
1059 // Collect all the relocate calls associated with a statepoint
1060 AllRelocateCalls.push_back(Relocate);
1061
1062 // We need at least one base pointer relocation + one derived pointer
1063 // relocation to mangle
1064 if (AllRelocateCalls.size() < 2)
1
Assuming the condition is false
2
Taking false branch
1065 return false;
1066
1067 // RelocateInstMap is a mapping from the base relocate instruction to the
1068 // corresponding derived relocate instructions
1069 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>> RelocateInstMap;
1070 computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
1071 if (RelocateInstMap.empty())
3
Assuming the condition is false
4
Taking false branch
1072 return false;
1073
1074 for (auto &Item : RelocateInstMap)
1075 // Item.first is the RelocatedBase to offset against
1076 // Item.second is the vector of Targets to replace
1077 MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
5
Calling 'simplifyRelocatesOffABase'
1078 return MadeChange;
1079}
1080
1081/// Sink the specified cast instruction into its user blocks.
1082static bool SinkCast(CastInst *CI) {
1083 BasicBlock *DefBB = CI->getParent();
1084
1085 /// InsertedCasts - Only insert a cast in each block once.
1086 DenseMap<BasicBlock*, CastInst*> InsertedCasts;
1087
1088 bool MadeChange = false;
1089 for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
1090 UI != E; ) {
1091 Use &TheUse = UI.getUse();
1092 Instruction *User = cast<Instruction>(*UI);
1093
1094 // Figure out which BB this cast is used in. For PHI's this is the
1095 // appropriate predecessor block.
1096 BasicBlock *UserBB = User->getParent();
1097 if (PHINode *PN = dyn_cast<PHINode>(User)) {
1098 UserBB = PN->getIncomingBlock(TheUse);
1099 }
1100
1101 // Preincrement use iterator so we don't invalidate it.
1102 ++UI;
1103
1104 // The first insertion point of a block containing an EH pad is after the
1105 // pad. If the pad is the user, we cannot sink the cast past the pad.
1106 if (User->isEHPad())
1107 continue;
1108
1109 // If the block selected to receive the cast is an EH pad that does not
1110 // allow non-PHI instructions before the terminator, we can't sink the
1111 // cast.
1112 if (UserBB->getTerminator()->isEHPad())
1113 continue;
1114
1115 // If this user is in the same block as the cast, don't change the cast.
1116 if (UserBB == DefBB) continue;
1117
1118 // If we have already inserted a cast into this block, use it.
1119 CastInst *&InsertedCast = InsertedCasts[UserBB];
1120
1121 if (!InsertedCast) {
1122 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1123 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1123, __PRETTY_FUNCTION__))
;
1124 InsertedCast = CastInst::Create(CI->getOpcode(), CI->getOperand(0),
1125 CI->getType(), "", &*InsertPt);
1126 InsertedCast->setDebugLoc(CI->getDebugLoc());
1127 }
1128
1129 // Replace a use of the cast with a use of the new cast.
1130 TheUse = InsertedCast;
1131 MadeChange = true;
1132 ++NumCastUses;
1133 }
1134
1135 // If we removed all uses, nuke the cast.
1136 if (CI->use_empty()) {
1137 salvageDebugInfo(*CI);
1138 CI->eraseFromParent();
1139 MadeChange = true;
1140 }
1141
1142 return MadeChange;
1143}
1144
1145/// If the specified cast instruction is a noop copy (e.g. it's casting from
1146/// one pointer type to another, i32->i8 on PPC), sink it into user blocks to
1147/// reduce the number of virtual registers that must be created and coalesced.
1148///
1149/// Return true if any changes are made.
1150static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI,
1151 const DataLayout &DL) {
1152 // Sink only "cheap" (or nop) address-space casts. This is a weaker condition
1153 // than sinking only nop casts, but is helpful on some platforms.
1154 if (auto *ASC = dyn_cast<AddrSpaceCastInst>(CI)) {
1155 if (!TLI.isFreeAddrSpaceCast(ASC->getSrcAddressSpace(),
1156 ASC->getDestAddressSpace()))
1157 return false;
1158 }
1159
1160 // If this is a noop copy,
1161 EVT SrcVT = TLI.getValueType(DL, CI->getOperand(0)->getType());
1162 EVT DstVT = TLI.getValueType(DL, CI->getType());
1163
1164 // This is an fp<->int conversion?
1165 if (SrcVT.isInteger() != DstVT.isInteger())
1166 return false;
1167
1168 // If this is an extension, it will be a zero or sign extension, which
1169 // isn't a noop.
1170 if (SrcVT.bitsLT(DstVT)) return false;
1171
1172 // If these values will be promoted, find out what they will be promoted
1173 // to. This helps us consider truncates on PPC as noop copies when they
1174 // are.
1175 if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
1176 TargetLowering::TypePromoteInteger)
1177 SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
1178 if (TLI.getTypeAction(CI->getContext(), DstVT) ==
1179 TargetLowering::TypePromoteInteger)
1180 DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
1181
1182 // If, after promotion, these are the same types, this is a noop copy.
1183 if (SrcVT != DstVT)
1184 return false;
1185
1186 return SinkCast(CI);
1187}
1188
1189bool CodeGenPrepare::replaceMathCmpWithIntrinsic(BinaryOperator *BO,
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 Value *Arg0 = BO->getOperand(0);
1208 Value *Arg1 = BO->getOperand(1);
1209 if (BO->getOpcode() == Instruction::Add &&
1210 IID == Intrinsic::usub_with_overflow) {
1211 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1211, __PRETTY_FUNCTION__))
;
1212 Arg1 = ConstantExpr::getNeg(cast<Constant>(Arg1));
1213 }
1214
1215 // Insert at the first instruction of the pair.
1216 Instruction *InsertPt = nullptr;
1217 for (Instruction &Iter : *Cmp->getParent()) {
1218 if (&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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1223, __PRETTY_FUNCTION__))
;
1224
1225 IRBuilder<> Builder(InsertPt);
1226 Value *MathOV = Builder.CreateBinaryIntrinsic(IID, Arg0, Arg1);
1227 Value *Math = Builder.CreateExtractValue(MathOV, 0, "math");
1228 Value *OV = Builder.CreateExtractValue(MathOV, 1, "ov");
1229 BO->replaceAllUsesWith(Math);
1230 Cmp->replaceAllUsesWith(OV);
1231 BO->eraseFromParent();
1232 Cmp->eraseFromParent();
1233 return true;
1234}
1235
1236/// Match special-case patterns that check for unsigned add overflow.
1237static bool matchUAddWithOverflowConstantEdgeCases(CmpInst *Cmp,
1238 BinaryOperator *&Add) {
1239 // Add = add A, 1; Cmp = icmp eq A,-1 (overflow if A is max val)
1240 // Add = add A,-1; Cmp = icmp ne A, 0 (overflow if A is non-zero)
1241 Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
1242
1243 // We are not expecting non-canonical/degenerate code. Just bail out.
1244 if (isa<Constant>(A))
1245 return false;
1246
1247 ICmpInst::Predicate Pred = Cmp->getPredicate();
1248 if (Pred == ICmpInst::ICMP_EQ && match(B, m_AllOnes()))
1249 B = ConstantInt::get(B->getType(), 1);
1250 else if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt()))
1251 B = ConstantInt::get(B->getType(), -1);
1252 else
1253 return false;
1254
1255 // Check the users of the variable operand of the compare looking for an add
1256 // with the adjusted constant.
1257 for (User *U : A->users()) {
1258 if (match(U, m_Add(m_Specific(A), m_Specific(B)))) {
1259 Add = cast<BinaryOperator>(U);
1260 return true;
1261 }
1262 }
1263 return false;
1264}
1265
1266/// Try to combine the compare into a call to the llvm.uadd.with.overflow
1267/// intrinsic. Return true if any changes were made.
1268bool CodeGenPrepare::combineToUAddWithOverflow(CmpInst *Cmp,
1269 bool &ModifiedDT) {
1270 Value *A, *B;
1271 BinaryOperator *Add;
1272 if (!match(Cmp, m_UAddWithOverflow(m_Value(A), m_Value(B), m_BinOp(Add))))
1273 if (!matchUAddWithOverflowConstantEdgeCases(Cmp, Add))
1274 return false;
1275
1276 if (!TLI->shouldFormOverflowOp(ISD::UADDO,
1277 TLI->getValueType(*DL, Add->getType())))
1278 return false;
1279
1280 // We don't want to move around uses of condition values this late, so we
1281 // check if it is legal to create the call to the intrinsic in the basic
1282 // block containing the icmp.
1283 if (Add->getParent() != Cmp->getParent() && !Add->hasOneUse())
1284 return false;
1285
1286 if (!replaceMathCmpWithIntrinsic(Add, Cmp, Intrinsic::uadd_with_overflow))
1287 return false;
1288
1289 // Reset callers - do not crash by iterating over a dead instruction.
1290 ModifiedDT = true;
1291 return true;
1292}
1293
1294bool CodeGenPrepare::combineToUSubWithOverflow(CmpInst *Cmp,
1295 bool &ModifiedDT) {
1296 // We are not expecting non-canonical/degenerate code. Just bail out.
1297 Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
1298 if (isa<Constant>(A) && isa<Constant>(B))
1299 return false;
1300
1301 // Convert (A u> B) to (A u< B) to simplify pattern matching.
1302 ICmpInst::Predicate Pred = Cmp->getPredicate();
1303 if (Pred == ICmpInst::ICMP_UGT) {
1304 std::swap(A, B);
1305 Pred = ICmpInst::ICMP_ULT;
1306 }
1307 // Convert special-case: (A == 0) is the same as (A u< 1).
1308 if (Pred == ICmpInst::ICMP_EQ && match(B, m_ZeroInt())) {
1309 B = ConstantInt::get(B->getType(), 1);
1310 Pred = ICmpInst::ICMP_ULT;
1311 }
1312 // Convert special-case: (A != 0) is the same as (0 u< A).
1313 if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt())) {
1314 std::swap(A, B);
1315 Pred = ICmpInst::ICMP_ULT;
1316 }
1317 if (Pred != ICmpInst::ICMP_ULT)
1318 return false;
1319
1320 // Walk the users of a variable operand of a compare looking for a subtract or
1321 // add with that same operand. Also match the 2nd operand of the compare to
1322 // the add/sub, but that may be a negated constant operand of an add.
1323 Value *CmpVariableOperand = isa<Constant>(A) ? B : A;
1324 BinaryOperator *Sub = nullptr;
1325 for (User *U : CmpVariableOperand->users()) {
1326 // A - B, A u< B --> usubo(A, B)
1327 if (match(U, m_Sub(m_Specific(A), m_Specific(B)))) {
1328 Sub = cast<BinaryOperator>(U);
1329 break;
1330 }
1331
1332 // A + (-C), A u< C (canonicalized form of (sub A, C))
1333 const APInt *CmpC, *AddC;
1334 if (match(U, m_Add(m_Specific(A), m_APInt(AddC))) &&
1335 match(B, m_APInt(CmpC)) && *AddC == -(*CmpC)) {
1336 Sub = cast<BinaryOperator>(U);
1337 break;
1338 }
1339 }
1340 if (!Sub)
1341 return false;
1342
1343 if (!TLI->shouldFormOverflowOp(ISD::USUBO,
1344 TLI->getValueType(*DL, Sub->getType())))
1345 return false;
1346
1347 if (!replaceMathCmpWithIntrinsic(Sub, Cmp, Intrinsic::usub_with_overflow))
1348 return false;
1349
1350 // Reset callers - do not crash by iterating over a dead instruction.
1351 ModifiedDT = true;
1352 return true;
1353}
1354
1355/// Sink the given CmpInst into user blocks to reduce the number of virtual
1356/// registers that must be created and coalesced. This is a clear win except on
1357/// targets with multiple condition code registers (PowerPC), where it might
1358/// lose; some adjustment may be wanted there.
1359///
1360/// Return true if any changes are made.
1361static bool sinkCmpExpression(CmpInst *Cmp, const TargetLowering &TLI) {
1362 if (TLI.hasMultipleConditionRegisters())
1363 return false;
1364
1365 // Avoid sinking soft-FP comparisons, since this can move them into a loop.
1366 if (TLI.useSoftFloat() && isa<FCmpInst>(Cmp))
1367 return false;
1368
1369 // Only insert a cmp in each block once.
1370 DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
1371
1372 bool MadeChange = false;
1373 for (Value::user_iterator UI = Cmp->user_begin(), E = Cmp->user_end();
1374 UI != E; ) {
1375 Use &TheUse = UI.getUse();
1376 Instruction *User = cast<Instruction>(*UI);
1377
1378 // Preincrement use iterator so we don't invalidate it.
1379 ++UI;
1380
1381 // Don't bother for PHI nodes.
1382 if (isa<PHINode>(User))
1383 continue;
1384
1385 // Figure out which BB this cmp is used in.
1386 BasicBlock *UserBB = User->getParent();
1387 BasicBlock *DefBB = Cmp->getParent();
1388
1389 // If this user is in the same block as the cmp, don't change the cmp.
1390 if (UserBB == DefBB) continue;
1391
1392 // If we have already inserted a cmp into this block, use it.
1393 CmpInst *&InsertedCmp = InsertedCmps[UserBB];
1394
1395 if (!InsertedCmp) {
1396 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1397 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1397, __PRETTY_FUNCTION__))
;
1398 InsertedCmp =
1399 CmpInst::Create(Cmp->getOpcode(), Cmp->getPredicate(),
1400 Cmp->getOperand(0), Cmp->getOperand(1), "",
1401 &*InsertPt);
1402 // Propagate the debug info.
1403 InsertedCmp->setDebugLoc(Cmp->getDebugLoc());
1404 }
1405
1406 // Replace a use of the cmp with a use of the new cmp.
1407 TheUse = InsertedCmp;
1408 MadeChange = true;
1409 ++NumCmpUses;
1410 }
1411
1412 // If we removed all uses, nuke the cmp.
1413 if (Cmp->use_empty()) {
1414 Cmp->eraseFromParent();
1415 MadeChange = true;
1416 }
1417
1418 return MadeChange;
1419}
1420
1421/// For pattern like:
1422///
1423/// DomCond = icmp sgt/slt CmpOp0, CmpOp1 (might not be in DomBB)
1424/// ...
1425/// DomBB:
1426/// ...
1427/// br DomCond, TrueBB, CmpBB
1428/// CmpBB: (with DomBB being the single predecessor)
1429/// ...
1430/// Cmp = icmp eq CmpOp0, CmpOp1
1431/// ...
1432///
1433/// It would use two comparison on targets that lowering of icmp sgt/slt is
1434/// different from lowering of icmp eq (PowerPC). This function try to convert
1435/// 'Cmp = icmp eq CmpOp0, CmpOp1' to ' Cmp = icmp slt/sgt CmpOp0, CmpOp1'.
1436/// After that, DomCond and Cmp can use the same comparison so reduce one
1437/// comparison.
1438///
1439/// Return true if any changes are made.
1440static bool foldICmpWithDominatingICmp(CmpInst *Cmp,
1441 const TargetLowering &TLI) {
1442 if (!EnableICMP_EQToICMP_ST && TLI.isEqualityCmpFoldedWithSignedCmp())
1443 return false;
1444
1445 ICmpInst::Predicate Pred = Cmp->getPredicate();
1446 if (Pred != ICmpInst::ICMP_EQ)
1447 return false;
1448
1449 // If icmp eq has users other than BranchInst and SelectInst, converting it to
1450 // icmp slt/sgt would introduce more redundant LLVM IR.
1451 for (User *U : Cmp->users()) {
1452 if (isa<BranchInst>(U))
1453 continue;
1454 if (isa<SelectInst>(U) && cast<SelectInst>(U)->getCondition() == Cmp)
1455 continue;
1456 return false;
1457 }
1458
1459 // This is a cheap/incomplete check for dominance - just match a single
1460 // predecessor with a conditional branch.
1461 BasicBlock *CmpBB = Cmp->getParent();
1462 BasicBlock *DomBB = CmpBB->getSinglePredecessor();
1463 if (!DomBB)
1464 return false;
1465
1466 // We want to ensure that the only way control gets to the comparison of
1467 // interest is that a less/greater than comparison on the same operands is
1468 // false.
1469 Value *DomCond;
1470 BasicBlock *TrueBB, *FalseBB;
1471 if (!match(DomBB->getTerminator(), m_Br(m_Value(DomCond), TrueBB, FalseBB)))
1472 return false;
1473 if (CmpBB != FalseBB)
1474 return false;
1475
1476 Value *CmpOp0 = Cmp->getOperand(0), *CmpOp1 = Cmp->getOperand(1);
1477 ICmpInst::Predicate DomPred;
1478 if (!match(DomCond, m_ICmp(DomPred, m_Specific(CmpOp0), m_Specific(CmpOp1))))
1479 return false;
1480 if (DomPred != ICmpInst::ICMP_SGT && DomPred != ICmpInst::ICMP_SLT)
1481 return false;
1482
1483 // Convert the equality comparison to the opposite of the dominating
1484 // comparison and swap the direction for all branch/select users.
1485 // We have conceptually converted:
1486 // Res = (a < b) ? <LT_RES> : (a == b) ? <EQ_RES> : <GT_RES>;
1487 // to
1488 // Res = (a < b) ? <LT_RES> : (a > b) ? <GT_RES> : <EQ_RES>;
1489 // And similarly for branches.
1490 for (User *U : Cmp->users()) {
1491 if (auto *BI = dyn_cast<BranchInst>(U)) {
1492 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1492, __PRETTY_FUNCTION__))
;
1493 BI->swapSuccessors();
1494 continue;
1495 }
1496 if (auto *SI = dyn_cast<SelectInst>(U)) {
1497 // Swap operands
1498 SI->swapValues();
1499 SI->swapProfMetadata();
1500 continue;
1501 }
1502 llvm_unreachable("Must be a branch or a select")::llvm::llvm_unreachable_internal("Must be a branch or a select"
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1502)
;
1503 }
1504 Cmp->setPredicate(CmpInst::getSwappedPredicate(DomPred));
1505 return true;
1506}
1507
1508bool CodeGenPrepare::optimizeCmp(CmpInst *Cmp, bool &ModifiedDT) {
1509 if (sinkCmpExpression(Cmp, *TLI))
1510 return true;
1511
1512 if (combineToUAddWithOverflow(Cmp, ModifiedDT))
1513 return true;
1514
1515 if (combineToUSubWithOverflow(Cmp, ModifiedDT))
1516 return true;
1517
1518 if (foldICmpWithDominatingICmp(Cmp, *TLI))
1519 return true;
1520
1521 return false;
1522}
1523
1524/// Duplicate and sink the given 'and' instruction into user blocks where it is
1525/// used in a compare to allow isel to generate better code for targets where
1526/// this operation can be combined.
1527///
1528/// Return true if any changes are made.
1529static bool sinkAndCmp0Expression(Instruction *AndI,
1530 const TargetLowering &TLI,
1531 SetOfInstrs &InsertedInsts) {
1532 // Double-check that we're not trying to optimize an instruction that was
1533 // already optimized by some other part of this pass.
1534 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1535, __PRETTY_FUNCTION__))
1535 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1535, __PRETTY_FUNCTION__))
;
1536 (void) InsertedInsts;
1537
1538 // Nothing to do for single use in same basic block.
1539 if (AndI->hasOneUse() &&
1540 AndI->getParent() == cast<Instruction>(*AndI->user_begin())->getParent())
1541 return false;
1542
1543 // Try to avoid cases where sinking/duplicating is likely to increase register
1544 // pressure.
1545 if (!isa<ConstantInt>(AndI->getOperand(0)) &&
1546 !isa<ConstantInt>(AndI->getOperand(1)) &&
1547 AndI->getOperand(0)->hasOneUse() && AndI->getOperand(1)->hasOneUse())
1548 return false;
1549
1550 for (auto *U : AndI->users()) {
1551 Instruction *User = cast<Instruction>(U);
1552
1553 // Only sink 'and' feeding icmp with 0.
1554 if (!isa<ICmpInst>(User))
1555 return false;
1556
1557 auto *CmpC = dyn_cast<ConstantInt>(User->getOperand(1));
1558 if (!CmpC || !CmpC->isZero())
1559 return false;
1560 }
1561
1562 if (!TLI.isMaskAndCmp0FoldingBeneficial(*AndI))
1563 return false;
1564
1565 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)
;
1566 LLVM_DEBUG(AndI->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { AndI->getParent()->dump(); } } while
(false)
;
1567
1568 // Push the 'and' into the same block as the icmp 0. There should only be
1569 // one (icmp (and, 0)) in each block, since CSE/GVN should have removed any
1570 // others, so we don't need to keep track of which BBs we insert into.
1571 for (Value::user_iterator UI = AndI->user_begin(), E = AndI->user_end();
1572 UI != E; ) {
1573 Use &TheUse = UI.getUse();
1574 Instruction *User = cast<Instruction>(*UI);
1575
1576 // Preincrement use iterator so we don't invalidate it.
1577 ++UI;
1578
1579 LLVM_DEBUG(dbgs() << "sinking 'and' use: " << *User << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "sinking 'and' use: " <<
*User << "\n"; } } while (false)
;
1580
1581 // Keep the 'and' in the same place if the use is already in the same block.
1582 Instruction *InsertPt =
1583 User->getParent() == AndI->getParent() ? AndI : User;
1584 Instruction *InsertedAnd =
1585 BinaryOperator::Create(Instruction::And, AndI->getOperand(0),
1586 AndI->getOperand(1), "", InsertPt);
1587 // Propagate the debug info.
1588 InsertedAnd->setDebugLoc(AndI->getDebugLoc());
1589
1590 // Replace a use of the 'and' with a use of the new 'and'.
1591 TheUse = InsertedAnd;
1592 ++NumAndUses;
1593 LLVM_DEBUG(User->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { User->getParent()->dump(); } } while
(false)
;
1594 }
1595
1596 // We removed all uses, nuke the and.
1597 AndI->eraseFromParent();
1598 return true;
1599}
1600
1601/// Check if the candidates could be combined with a shift instruction, which
1602/// includes:
1603/// 1. Truncate instruction
1604/// 2. And instruction and the imm is a mask of the low bits:
1605/// imm & (imm+1) == 0
1606static bool isExtractBitsCandidateUse(Instruction *User) {
1607 if (!isa<TruncInst>(User)) {
1608 if (User->getOpcode() != Instruction::And ||
1609 !isa<ConstantInt>(User->getOperand(1)))
1610 return false;
1611
1612 const APInt &Cimm = cast<ConstantInt>(User->getOperand(1))->getValue();
1613
1614 if ((Cimm & (Cimm + 1)).getBoolValue())
1615 return false;
1616 }
1617 return true;
1618}
1619
1620/// Sink both shift and truncate instruction to the use of truncate's BB.
1621static bool
1622SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI,
1623 DenseMap<BasicBlock *, BinaryOperator *> &InsertedShifts,
1624 const TargetLowering &TLI, const DataLayout &DL) {
1625 BasicBlock *UserBB = User->getParent();
1626 DenseMap<BasicBlock *, CastInst *> InsertedTruncs;
1627 auto *TruncI = cast<TruncInst>(User);
1628 bool MadeChange = false;
1629
1630 for (Value::user_iterator TruncUI = TruncI->user_begin(),
1631 TruncE = TruncI->user_end();
1632 TruncUI != TruncE;) {
1633
1634 Use &TruncTheUse = TruncUI.getUse();
1635 Instruction *TruncUser = cast<Instruction>(*TruncUI);
1636 // Preincrement use iterator so we don't invalidate it.
1637
1638 ++TruncUI;
1639
1640 int ISDOpcode = TLI.InstructionOpcodeToISD(TruncUser->getOpcode());
1641 if (!ISDOpcode)
1642 continue;
1643
1644 // If the use is actually a legal node, there will not be an
1645 // implicit truncate.
1646 // FIXME: always querying the result type is just an
1647 // approximation; some nodes' legality is determined by the
1648 // operand or other means. There's no good way to find out though.
1649 if (TLI.isOperationLegalOrCustom(
1650 ISDOpcode, TLI.getValueType(DL, TruncUser->getType(), true)))
1651 continue;
1652
1653 // Don't bother for PHI nodes.
1654 if (isa<PHINode>(TruncUser))
1655 continue;
1656
1657 BasicBlock *TruncUserBB = TruncUser->getParent();
1658
1659 if (UserBB == TruncUserBB)
1660 continue;
1661
1662 BinaryOperator *&InsertedShift = InsertedShifts[TruncUserBB];
1663 CastInst *&InsertedTrunc = InsertedTruncs[TruncUserBB];
1664
1665 if (!InsertedShift && !InsertedTrunc) {
1666 BasicBlock::iterator InsertPt = TruncUserBB->getFirstInsertionPt();
1667 assert(InsertPt != TruncUserBB->end())((InsertPt != TruncUserBB->end()) ? static_cast<void>
(0) : __assert_fail ("InsertPt != TruncUserBB->end()", "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1667, __PRETTY_FUNCTION__))
;
1668 // Sink the shift
1669 if (ShiftI->getOpcode() == Instruction::AShr)
1670 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1671 "", &*InsertPt);
1672 else
1673 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1674 "", &*InsertPt);
1675 InsertedShift->setDebugLoc(ShiftI->getDebugLoc());
1676
1677 // Sink the trunc
1678 BasicBlock::iterator TruncInsertPt = TruncUserBB->getFirstInsertionPt();
1679 TruncInsertPt++;
1680 assert(TruncInsertPt != TruncUserBB->end())((TruncInsertPt != TruncUserBB->end()) ? static_cast<void
> (0) : __assert_fail ("TruncInsertPt != TruncUserBB->end()"
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1680, __PRETTY_FUNCTION__))
;
1681
1682 InsertedTrunc = CastInst::Create(TruncI->getOpcode(), InsertedShift,
1683 TruncI->getType(), "", &*TruncInsertPt);
1684 InsertedTrunc->setDebugLoc(TruncI->getDebugLoc());
1685
1686 MadeChange = true;
1687
1688 TruncTheUse = InsertedTrunc;
1689 }
1690 }
1691 return MadeChange;
1692}
1693
1694/// Sink the shift *right* instruction into user blocks if the uses could
1695/// potentially be combined with this shift instruction and generate BitExtract
1696/// instruction. It will only be applied if the architecture supports BitExtract
1697/// instruction. Here is an example:
1698/// BB1:
1699/// %x.extract.shift = lshr i64 %arg1, 32
1700/// BB2:
1701/// %x.extract.trunc = trunc i64 %x.extract.shift to i16
1702/// ==>
1703///
1704/// BB2:
1705/// %x.extract.shift.1 = lshr i64 %arg1, 32
1706/// %x.extract.trunc = trunc i64 %x.extract.shift.1 to i16
1707///
1708/// CodeGen will recognize the pattern in BB2 and generate BitExtract
1709/// instruction.
1710/// Return true if any changes are made.
1711static bool OptimizeExtractBits(BinaryOperator *ShiftI, ConstantInt *CI,
1712 const TargetLowering &TLI,
1713 const DataLayout &DL) {
1714 BasicBlock *DefBB = ShiftI->getParent();
1715
1716 /// Only insert instructions in each block once.
1717 DenseMap<BasicBlock *, BinaryOperator *> InsertedShifts;
1718
1719 bool shiftIsLegal = TLI.isTypeLegal(TLI.getValueType(DL, ShiftI->getType()));
1720
1721 bool MadeChange = false;
1722 for (Value::user_iterator UI = ShiftI->user_begin(), E = ShiftI->user_end();
1723 UI != E;) {
1724 Use &TheUse = UI.getUse();
1725 Instruction *User = cast<Instruction>(*UI);
1726 // Preincrement use iterator so we don't invalidate it.
1727 ++UI;
1728
1729 // Don't bother for PHI nodes.
1730 if (isa<PHINode>(User))
1731 continue;
1732
1733 if (!isExtractBitsCandidateUse(User))
1734 continue;
1735
1736 BasicBlock *UserBB = User->getParent();
1737
1738 if (UserBB == DefBB) {
1739 // If the shift and truncate instruction are in the same BB. The use of
1740 // the truncate(TruncUse) may still introduce another truncate if not
1741 // legal. In this case, we would like to sink both shift and truncate
1742 // instruction to the BB of TruncUse.
1743 // for example:
1744 // BB1:
1745 // i64 shift.result = lshr i64 opnd, imm
1746 // trunc.result = trunc shift.result to i16
1747 //
1748 // BB2:
1749 // ----> We will have an implicit truncate here if the architecture does
1750 // not have i16 compare.
1751 // cmp i16 trunc.result, opnd2
1752 //
1753 if (isa<TruncInst>(User) && shiftIsLegal
1754 // If the type of the truncate is legal, no truncate will be
1755 // introduced in other basic blocks.
1756 &&
1757 (!TLI.isTypeLegal(TLI.getValueType(DL, User->getType()))))
1758 MadeChange =
1759 SinkShiftAndTruncate(ShiftI, User, CI, InsertedShifts, TLI, DL);
1760
1761 continue;
1762 }
1763 // If we have already inserted a shift into this block, use it.
1764 BinaryOperator *&InsertedShift = InsertedShifts[UserBB];
1765
1766 if (!InsertedShift) {
1767 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1768 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1768, __PRETTY_FUNCTION__))
;
1769
1770 if (ShiftI->getOpcode() == Instruction::AShr)
1771 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1772 "", &*InsertPt);
1773 else
1774 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1775 "", &*InsertPt);
1776 InsertedShift->setDebugLoc(ShiftI->getDebugLoc());
1777
1778 MadeChange = true;
1779 }
1780
1781 // Replace a use of the shift with a use of the new shift.
1782 TheUse = InsertedShift;
1783 }
1784
1785 // If we removed all uses, or there are none, nuke the shift.
1786 if (ShiftI->use_empty()) {
1787 salvageDebugInfo(*ShiftI);
1788 ShiftI->eraseFromParent();
1789 MadeChange = true;
1790 }
1791
1792 return MadeChange;
1793}
1794
1795/// If counting leading or trailing zeros is an expensive operation and a zero
1796/// input is defined, add a check for zero to avoid calling the intrinsic.
1797///
1798/// We want to transform:
1799/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 false)
1800///
1801/// into:
1802/// entry:
1803/// %cmpz = icmp eq i64 %A, 0
1804/// br i1 %cmpz, label %cond.end, label %cond.false
1805/// cond.false:
1806/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 true)
1807/// br label %cond.end
1808/// cond.end:
1809/// %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ]
1810///
1811/// If the transform is performed, return true and set ModifiedDT to true.
1812static bool despeculateCountZeros(IntrinsicInst *CountZeros,
1813 const TargetLowering *TLI,
1814 const DataLayout *DL,
1815 bool &ModifiedDT) {
1816 if (!TLI || !DL)
1817 return false;
1818
1819 // If a zero input is undefined, it doesn't make sense to despeculate that.
1820 if (match(CountZeros->getOperand(1), m_One()))
1821 return false;
1822
1823 // If it's cheap to speculate, there's nothing to do.
1824 auto IntrinsicID = CountZeros->getIntrinsicID();
1825 if ((IntrinsicID == Intrinsic::cttz && TLI->isCheapToSpeculateCttz()) ||
1826 (IntrinsicID == Intrinsic::ctlz && TLI->isCheapToSpeculateCtlz()))
1827 return false;
1828
1829 // Only handle legal scalar cases. Anything else requires too much work.
1830 Type *Ty = CountZeros->getType();
1831 unsigned SizeInBits = Ty->getPrimitiveSizeInBits();
1832 if (Ty->isVectorTy() || SizeInBits > DL->getLargestLegalIntTypeSizeInBits())
1833 return false;
1834
1835 // The intrinsic will be sunk behind a compare against zero and branch.
1836 BasicBlock *StartBlock = CountZeros->getParent();
1837 BasicBlock *CallBlock = StartBlock->splitBasicBlock(CountZeros, "cond.false");
1838
1839 // Create another block after the count zero intrinsic. A PHI will be added
1840 // in this block to select the result of the intrinsic or the bit-width
1841 // constant if the input to the intrinsic is zero.
1842 BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(CountZeros));
1843 BasicBlock *EndBlock = CallBlock->splitBasicBlock(SplitPt, "cond.end");
1844
1845 // Set up a builder to create a compare, conditional branch, and PHI.
1846 IRBuilder<> Builder(CountZeros->getContext());
1847 Builder.SetInsertPoint(StartBlock->getTerminator());
1848 Builder.SetCurrentDebugLocation(CountZeros->getDebugLoc());
1849
1850 // Replace the unconditional branch that was created by the first split with
1851 // a compare against zero and a conditional branch.
1852 Value *Zero = Constant::getNullValue(Ty);
1853 Value *Cmp = Builder.CreateICmpEQ(CountZeros->getOperand(0), Zero, "cmpz");
1854 Builder.CreateCondBr(Cmp, EndBlock, CallBlock);
1855 StartBlock->getTerminator()->eraseFromParent();
1856
1857 // Create a PHI in the end block to select either the output of the intrinsic
1858 // or the bit width of the operand.
1859 Builder.SetInsertPoint(&EndBlock->front());
1860 PHINode *PN = Builder.CreatePHI(Ty, 2, "ctz");
1861 CountZeros->replaceAllUsesWith(PN);
1862 Value *BitWidth = Builder.getInt(APInt(SizeInBits, SizeInBits));
1863 PN->addIncoming(BitWidth, StartBlock);
1864 PN->addIncoming(CountZeros, CallBlock);
1865
1866 // We are explicitly handling the zero case, so we can set the intrinsic's
1867 // undefined zero argument to 'true'. This will also prevent reprocessing the
1868 // intrinsic; we only despeculate when a zero input is defined.
1869 CountZeros->setArgOperand(1, Builder.getTrue());
1870 ModifiedDT = true;
1871 return true;
1872}
1873
1874bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool &ModifiedDT) {
1875 BasicBlock *BB = CI->getParent();
1876
1877 // Lower inline assembly if we can.
1878 // If we found an inline asm expession, and if the target knows how to
1879 // lower it to normal LLVM code, do so now.
1880 if (TLI && isa<InlineAsm>(CI->getCalledValue())) {
1881 if (TLI->ExpandInlineAsm(CI)) {
1882 // Avoid invalidating the iterator.
1883 CurInstIterator = BB->begin();
1884 // Avoid processing instructions out of order, which could cause
1885 // reuse before a value is defined.
1886 SunkAddrs.clear();
1887 return true;
1888 }
1889 // Sink address computing for memory operands into the block.
1890 if (optimizeInlineAsmInst(CI))
1891 return true;
1892 }
1893
1894 // Align the pointer arguments to this call if the target thinks it's a good
1895 // idea
1896 unsigned MinSize, PrefAlign;
1897 if (TLI && TLI->shouldAlignPointerArgs(CI, MinSize, PrefAlign)) {
1898 for (auto &Arg : CI->arg_operands()) {
1899 // We want to align both objects whose address is used directly and
1900 // objects whose address is used in casts and GEPs, though it only makes
1901 // sense for GEPs if the offset is a multiple of the desired alignment and
1902 // if size - offset meets the size threshold.
1903 if (!Arg->getType()->isPointerTy())
1904 continue;
1905 APInt Offset(DL->getIndexSizeInBits(
1906 cast<PointerType>(Arg->getType())->getAddressSpace()),
1907 0);
1908 Value *Val = Arg->stripAndAccumulateInBoundsConstantOffsets(*DL, Offset);
1909 uint64_t Offset2 = Offset.getLimitedValue();
1910 if ((Offset2 & (PrefAlign-1)) != 0)
1911 continue;
1912 AllocaInst *AI;
1913 if ((AI = dyn_cast<AllocaInst>(Val)) && AI->getAlignment() < PrefAlign &&
1914 DL->getTypeAllocSize(AI->getAllocatedType()) >= MinSize + Offset2)
1915 AI->setAlignment(MaybeAlign(PrefAlign));
1916 // Global variables can only be aligned if they are defined in this
1917 // object (i.e. they are uniquely initialized in this object), and
1918 // over-aligning global variables that have an explicit section is
1919 // forbidden.
1920 GlobalVariable *GV;
1921 if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() &&
1922 GV->getPointerAlignment(*DL) < PrefAlign &&
1923 DL->getTypeAllocSize(GV->getValueType()) >=
1924 MinSize + Offset2)
1925 GV->setAlignment(MaybeAlign(PrefAlign));
1926 }
1927 // If this is a memcpy (or similar) then we may be able to improve the
1928 // alignment
1929 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(CI)) {
1930 unsigned DestAlign = getKnownAlignment(MI->getDest(), *DL);
1931 if (DestAlign > MI->getDestAlignment())
1932 MI->setDestAlignment(DestAlign);
1933 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
1934 unsigned SrcAlign = getKnownAlignment(MTI->getSource(), *DL);
1935 if (SrcAlign > MTI->getSourceAlignment())
1936 MTI->setSourceAlignment(SrcAlign);
1937 }
1938 }
1939 }
1940
1941 // If we have a cold call site, try to sink addressing computation into the
1942 // cold block. This interacts with our handling for loads and stores to
1943 // ensure that we can fold all uses of a potential addressing computation
1944 // into their uses. TODO: generalize this to work over profiling data
1945 bool OptForSize = OptSize || llvm::shouldOptimizeForSize(BB, PSI, BFI.get());
1946 if (!OptForSize && CI->hasFnAttr(Attribute::Cold))
1947 for (auto &Arg : CI->arg_operands()) {
1948 if (!Arg->getType()->isPointerTy())
1949 continue;
1950 unsigned AS = Arg->getType()->getPointerAddressSpace();
1951 return optimizeMemoryInst(CI, Arg, Arg->getType(), AS);
1952 }
1953
1954 IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
1955 if (II) {
1956 switch (II->getIntrinsicID()) {
1957 default: break;
1958 case Intrinsic::experimental_widenable_condition: {
1959 // Give up on future widening oppurtunties so that we can fold away dead
1960 // paths and merge blocks before going into block-local instruction
1961 // selection.
1962 if (II->use_empty()) {
1963 II->eraseFromParent();
1964 return true;
1965 }
1966 Constant *RetVal = ConstantInt::getTrue(II->getContext());
1967 resetIteratorIfInvalidatedWhileCalling(BB, [&]() {
1968 replaceAndRecursivelySimplify(CI, RetVal, TLInfo, nullptr);
1969 });
1970 return true;
1971 }
1972 case Intrinsic::objectsize:
1973 llvm_unreachable("llvm.objectsize.* should have been lowered already")::llvm::llvm_unreachable_internal("llvm.objectsize.* should have been lowered already"
, "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1973)
;
1974 case Intrinsic::is_constant:
1975 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1975)
;
1976 case Intrinsic::aarch64_stlxr:
1977 case Intrinsic::aarch64_stxr: {
1978 ZExtInst *ExtVal = dyn_cast<ZExtInst>(CI->getArgOperand(0));
1979 if (!ExtVal || !ExtVal->hasOneUse() ||
1980 ExtVal->getParent() == CI->getParent())
1981 return false;
1982 // Sink a zext feeding stlxr/stxr before it, so it can be folded into it.
1983 ExtVal->moveBefore(CI);
1984 // Mark this instruction as "inserted by CGP", so that other
1985 // optimizations don't touch it.
1986 InsertedInsts.insert(ExtVal);
1987 return true;
1988 }
1989
1990 case Intrinsic::launder_invariant_group:
1991 case Intrinsic::strip_invariant_group: {
1992 Value *ArgVal = II->getArgOperand(0);
1993 auto it = LargeOffsetGEPMap.find(II);
1994 if (it != LargeOffsetGEPMap.end()) {
1995 // Merge entries in LargeOffsetGEPMap to reflect the RAUW.
1996 // Make sure not to have to deal with iterator invalidation
1997 // after possibly adding ArgVal to LargeOffsetGEPMap.
1998 auto GEPs = std::move(it->second);
1999 LargeOffsetGEPMap[ArgVal].append(GEPs.begin(), GEPs.end());
2000 LargeOffsetGEPMap.erase(II);
2001 }
2002
2003 II->replaceAllUsesWith(ArgVal);
2004 II->eraseFromParent();
2005 return true;
2006 }
2007 case Intrinsic::cttz:
2008 case Intrinsic::ctlz:
2009 // If counting zeros is expensive, try to avoid it.
2010 return despeculateCountZeros(II, TLI, DL, ModifiedDT);
2011 case Intrinsic::dbg_value:
2012 return fixupDbgValue(II);
2013 }
2014
2015 if (TLI) {
2016 SmallVector<Value*, 2> PtrOps;
2017 Type *AccessTy;
2018 if (TLI->getAddrModeArguments(II, PtrOps, AccessTy))
2019 while (!PtrOps.empty()) {
2020 Value *PtrVal = PtrOps.pop_back_val();
2021 unsigned AS = PtrVal->getType()->getPointerAddressSpace();
2022 if (optimizeMemoryInst(II, PtrVal, AccessTy, AS))
2023 return true;
2024 }
2025 }
2026 }
2027
2028 // From here on out we're working with named functions.
2029 if (!CI->getCalledFunction()) return false;
2030
2031 // Lower all default uses of _chk calls. This is very similar
2032 // to what InstCombineCalls does, but here we are only lowering calls
2033 // to fortified library functions (e.g. __memcpy_chk) that have the default
2034 // "don't know" as the objectsize. Anything else should be left alone.
2035 FortifiedLibCallSimplifier Simplifier(TLInfo, true);
2036 if (Value *V = Simplifier.optimizeCall(CI)) {
2037 CI->replaceAllUsesWith(V);
2038 CI->eraseFromParent();
2039 return true;
2040 }
2041
2042 return false;
2043}
2044
2045/// Look for opportunities to duplicate return instructions to the predecessor
2046/// to enable tail call optimizations. The case it is currently looking for is:
2047/// @code
2048/// bb0:
2049/// %tmp0 = tail call i32 @f0()
2050/// br label %return
2051/// bb1:
2052/// %tmp1 = tail call i32 @f1()
2053/// br label %return
2054/// bb2:
2055/// %tmp2 = tail call i32 @f2()
2056/// br label %return
2057/// return:
2058/// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
2059/// ret i32 %retval
2060/// @endcode
2061///
2062/// =>
2063///
2064/// @code
2065/// bb0:
2066/// %tmp0 = tail call i32 @f0()
2067/// ret i32 %tmp0
2068/// bb1:
2069/// %tmp1 = tail call i32 @f1()
2070/// ret i32 %tmp1
2071/// bb2:
2072/// %tmp2 = tail call i32 @f2()
2073/// ret i32 %tmp2
2074/// @endcode
2075bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT) {
2076 if (!TLI)
2077 return false;
2078
2079 ReturnInst *RetI = dyn_cast<ReturnInst>(BB->getTerminator());
2080 if (!RetI)
2081 return false;
2082
2083 PHINode *PN = nullptr;
2084 BitCastInst *BCI = nullptr;
2085 Value *V = RetI->getReturnValue();
2086 if (V) {
2087 BCI = dyn_cast<BitCastInst>(V);
2088 if (BCI)
2089 V = BCI->getOperand(0);
2090
2091 PN = dyn_cast<PHINode>(V);
2092 if (!PN)
2093 return false;
2094 }
2095
2096 if (PN && PN->getParent() != BB)
2097 return false;
2098
2099 // Make sure there are no instructions between the PHI and return, or that the
2100 // return is the first instruction in the block.
2101 if (PN) {
2102 BasicBlock::iterator BI = BB->begin();
2103 // Skip over debug and the bitcast.
2104 do { ++BI; } while (isa<DbgInfoIntrinsic>(BI) || &*BI == BCI);
2105 if (&*BI != RetI)
2106 return false;
2107 } else {
2108 BasicBlock::iterator BI = BB->begin();
2109 while (isa<DbgInfoIntrinsic>(BI)) ++BI;
2110 if (&*BI != RetI)
2111 return false;
2112 }
2113
2114 /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
2115 /// call.
2116 const Function *F = BB->getParent();
2117 SmallVector<BasicBlock*, 4> TailCallBBs;
2118 if (PN) {
2119 for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
2120 // Look through bitcasts.
2121 Value *IncomingVal = PN->getIncomingValue(I)->stripPointerCasts();
2122 CallInst *CI = dyn_cast<CallInst>(IncomingVal);
2123 BasicBlock *PredBB = PN->getIncomingBlock(I);
2124 // Make sure the phi value is indeed produced by the tail call.
2125 if (CI && CI->hasOneUse() && CI->getParent() == PredBB &&
2126 TLI->mayBeEmittedAsTailCall(CI) &&
2127 attributesPermitTailCall(F, CI, RetI, *TLI))
2128 TailCallBBs.push_back(PredBB);
2129 }
2130 } else {
2131 SmallPtrSet<BasicBlock*, 4> VisitedBBs;
2132 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
2133 if (!VisitedBBs.insert(*PI).second)
2134 continue;
2135
2136 BasicBlock::InstListType &InstList = (*PI)->getInstList();
2137 BasicBlock::InstListType::reverse_iterator RI = InstList.rbegin();
2138 BasicBlock::InstListType::reverse_iterator RE = InstList.rend();
2139 do { ++RI; } while (RI != RE && isa<DbgInfoIntrinsic>(&*RI));
2140 if (RI == RE)
2141 continue;
2142
2143 CallInst *CI = dyn_cast<CallInst>(&*RI);
2144 if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI) &&
2145 attributesPermitTailCall(F, CI, RetI, *TLI))
2146 TailCallBBs.push_back(*PI);
2147 }
2148 }
2149
2150 bool Changed = false;
2151 for (auto const &TailCallBB : TailCallBBs) {
2152 // Make sure the call instruction is followed by an unconditional branch to
2153 // the return block.
2154 BranchInst *BI = dyn_cast<BranchInst>(TailCallBB->getTerminator());
2155 if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
2156 continue;
2157
2158 // Duplicate the return into TailCallBB.
2159 (void)FoldReturnIntoUncondBranch(RetI, BB, TailCallBB);
2160 ModifiedDT = Changed = true;
2161 ++NumRetsDup;
2162 }
2163
2164 // If we eliminated all predecessors of the block, delete the block now.
2165 if (Changed && !BB->hasAddressTaken() && pred_begin(BB) == pred_end(BB))
2166 BB->eraseFromParent();
2167
2168 return Changed;
2169}
2170
2171//===----------------------------------------------------------------------===//
2172// Memory Optimization
2173//===----------------------------------------------------------------------===//
2174
2175namespace {
2176
2177/// This is an extended version of TargetLowering::AddrMode
2178/// which holds actual Value*'s for register values.
2179struct ExtAddrMode : public TargetLowering::AddrMode {
2180 Value *BaseReg = nullptr;
2181 Value *ScaledReg = nullptr;
2182 Value *OriginalValue = nullptr;
2183 bool InBounds = true;
2184
2185 enum FieldName {
2186 NoField = 0x00,
2187 BaseRegField = 0x01,
2188 BaseGVField = 0x02,
2189 BaseOffsField = 0x04,
2190 ScaledRegField = 0x08,
2191 ScaleField = 0x10,
2192 MultipleFields = 0xff
2193 };
2194
2195
2196 ExtAddrMode() = default;
2197
2198 void print(raw_ostream &OS) const;
2199 void dump() const;
2200
2201 FieldName compare(const ExtAddrMode &other) {
2202 // First check that the types are the same on each field, as differing types
2203 // is something we can't cope with later on.
2204 if (BaseReg && other.BaseReg &&
2205 BaseReg->getType() != other.BaseReg->getType())
2206 return MultipleFields;
2207 if (BaseGV && other.BaseGV &&
2208 BaseGV->getType() != other.BaseGV->getType())
2209 return MultipleFields;
2210 if (ScaledReg && other.ScaledReg &&
2211 ScaledReg->getType() != other.ScaledReg->getType())
2212 return MultipleFields;
2213
2214 // Conservatively reject 'inbounds' mismatches.
2215 if (InBounds != other.InBounds)
2216 return MultipleFields;
2217
2218 // Check each field to see if it differs.
2219 unsigned Result = NoField;
2220 if (BaseReg != other.BaseReg)
2221 Result |= BaseRegField;
2222 if (BaseGV != other.BaseGV)
2223 Result |= BaseGVField;
2224 if (BaseOffs != other.BaseOffs)
2225 Result |= BaseOffsField;
2226 if (ScaledReg != other.ScaledReg)
2227 Result |= ScaledRegField;
2228 // Don't count 0 as being a different scale, because that actually means
2229 // unscaled (which will already be counted by having no ScaledReg).
2230 if (Scale && other.Scale && Scale != other.Scale)
2231 Result |= ScaleField;
2232
2233 if (countPopulation(Result) > 1)
2234 return MultipleFields;
2235 else
2236 return static_cast<FieldName>(Result);
2237 }
2238
2239 // An AddrMode is trivial if it involves no calculation i.e. it is just a base
2240 // with no offset.
2241 bool isTrivial() {
2242 // An AddrMode is (BaseGV + BaseReg + BaseOffs + ScaleReg * Scale) so it is
2243 // trivial if at most one of these terms is nonzero, except that BaseGV and
2244 // BaseReg both being zero actually means a null pointer value, which we
2245 // consider to be 'non-zero' here.
2246 return !BaseOffs && !Scale && !(BaseGV && BaseReg);
2247 }
2248
2249 Value *GetFieldAsValue(FieldName Field, Type *IntPtrTy) {
2250 switch (Field) {
2251 default:
2252 return nullptr;
2253 case BaseRegField:
2254 return BaseReg;
2255 case BaseGVField:
2256 return BaseGV;
2257 case ScaledRegField:
2258 return ScaledReg;
2259 case BaseOffsField:
2260 return ConstantInt::get(IntPtrTy, BaseOffs);
2261 }
2262 }
2263
2264 void SetCombinedField(FieldName Field, Value *V,
2265 const SmallVectorImpl<ExtAddrMode> &AddrModes) {
2266 switch (Field) {
2267 default:
2268 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2268)
;
2269 break;
2270 case ExtAddrMode::BaseRegField:
2271 BaseReg = V;
2272 break;
2273 case ExtAddrMode::BaseGVField:
2274 // A combined BaseGV is an Instruction, not a GlobalValue, so it goes
2275 // in the BaseReg field.
2276 assert(BaseReg == nullptr)((BaseReg == nullptr) ? static_cast<void> (0) : __assert_fail
("BaseReg == nullptr", "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2276, __PRETTY_FUNCTION__))
;
2277 BaseReg = V;
2278 BaseGV = nullptr;
2279 break;
2280 case ExtAddrMode::ScaledRegField:
2281 ScaledReg = V;
2282 // If we have a mix of scaled and unscaled addrmodes then we want scale
2283 // to be the scale and not zero.
2284 if (!Scale)
2285 for (const ExtAddrMode &AM : AddrModes)
2286 if (AM.Scale) {
2287 Scale = AM.Scale;
2288 break;
2289 }
2290 break;
2291 case ExtAddrMode::BaseOffsField:
2292 // The offset is no longer a constant, so it goes in ScaledReg with a
2293 // scale of 1.
2294 assert(ScaledReg == nullptr)((ScaledReg == nullptr) ? static_cast<void> (0) : __assert_fail
("ScaledReg == nullptr", "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2294, __PRETTY_FUNCTION__))
;
2295 ScaledReg = V;
2296 Scale = 1;
2297 BaseOffs = 0;
2298 break;
2299 }
2300 }
2301};
2302
2303} // end anonymous namespace
2304
2305#ifndef NDEBUG
2306static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
2307 AM.print(OS);
2308 return OS;
2309}
2310#endif
2311
2312#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
2313void ExtAddrMode::print(raw_ostream &OS) const {
2314 bool NeedPlus = false;
2315 OS << "[";
2316 if (InBounds)
2317 OS << "inbounds ";
2318 if (BaseGV) {
2319 OS << (NeedPlus ? " + " : "")
2320 << "GV:";
2321 BaseGV->printAsOperand(OS, /*PrintType=*/false);
2322 NeedPlus = true;
2323 }
2324
2325 if (BaseOffs) {
2326 OS << (NeedPlus ? " + " : "")
2327 << BaseOffs;
2328 NeedPlus = true;
2329 }
2330
2331 if (BaseReg) {
2332 OS << (NeedPlus ? " + " : "")
2333 << "Base:";
2334 BaseReg->printAsOperand(OS, /*PrintType=*/false);
2335 NeedPlus = true;
2336 }
2337 if (Scale) {
2338 OS << (NeedPlus ? " + " : "")
2339 << Scale << "*";
2340 ScaledReg->printAsOperand(OS, /*PrintType=*/false);
2341 }
2342
2343 OS << ']';
2344}
2345
2346LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void ExtAddrMode::dump() const {
2347 print(dbgs());
2348 dbgs() << '\n';
2349}
2350#endif
2351
2352namespace {
2353
2354/// This class provides transaction based operation on the IR.
2355/// Every change made through this class is recorded in the internal state and
2356/// can be undone (rollback) until commit is called.
2357class TypePromotionTransaction {
2358 /// This represents the common interface of the individual transaction.
2359 /// Each class implements the logic for doing one specific modification on
2360 /// the IR via the TypePromotionTransaction.
2361 class TypePromotionAction {
2362 protected:
2363 /// The Instruction modified.
2364 Instruction *Inst;
2365
2366 public:
2367 /// Constructor of the action.
2368 /// The constructor performs the related action on the IR.
2369 TypePromotionAction(Instruction *Inst) : Inst(Inst) {}
2370
2371 virtual ~TypePromotionAction() = default;
2372
2373 /// Undo the modification done by this action.
2374 /// When this method is called, the IR must be in the same state as it was
2375 /// before this action was applied.
2376 /// \pre Undoing the action works if and only if the IR is in the exact same
2377 /// state as it was directly after this action was applied.
2378 virtual void undo() = 0;
2379
2380 /// Advocate every change made by this action.
2381 /// When the results on the IR of the action are to be kept, it is important
2382 /// to call this function, otherwise hidden information may be kept forever.
2383 virtual void commit() {
2384 // Nothing to be done, this action is not doing anything.
2385 }
2386 };
2387
2388 /// Utility to remember the position of an instruction.
2389 class InsertionHandler {
2390 /// Position of an instruction.
2391 /// Either an instruction:
2392 /// - Is the first in a basic block: BB is used.
2393 /// - Has a previous instruction: PrevInst is used.
2394 union {
2395 Instruction *PrevInst;
2396 BasicBlock *BB;
2397 } Point;
2398
2399 /// Remember whether or not the instruction had a previous instruction.
2400 bool HasPrevInstruction;
2401
2402 public:
2403 /// Record the position of \p Inst.
2404 InsertionHandler(Instruction *Inst) {
2405 BasicBlock::iterator It = Inst->getIterator();
2406 HasPrevInstruction = (It != (Inst->getParent()->begin()));
2407 if (HasPrevInstruction)
2408 Point.PrevInst = &*--It;
2409 else
2410 Point.BB = Inst->getParent();
2411 }
2412
2413 /// Insert \p Inst at the recorded position.
2414 void insert(Instruction *Inst) {
2415 if (HasPrevInstruction) {
2416 if (Inst->getParent())
2417 Inst->removeFromParent();
2418 Inst->insertAfter(Point.PrevInst);
2419 } else {
2420 Instruction *Position = &*Point.BB->getFirstInsertionPt();
2421 if (Inst->getParent())
2422 Inst->moveBefore(Position);
2423 else
2424 Inst->insertBefore(Position);
2425 }
2426 }
2427 };
2428
2429 /// Move an instruction before another.
2430 class InstructionMoveBefore : public TypePromotionAction {
2431 /// Original position of the instruction.
2432 InsertionHandler Position;
2433
2434 public:
2435 /// Move \p Inst before \p Before.
2436 InstructionMoveBefore(Instruction *Inst, Instruction *Before)
2437 : TypePromotionAction(Inst), Position(Inst) {
2438 LLVM_DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Beforedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: move: " << *
Inst << "\nbefore: " << *Before << "\n"; } }
while (false)
2439 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: move: " << *
Inst << "\nbefore: " << *Before << "\n"; } }
while (false)
;
2440 Inst->moveBefore(Before);
2441 }
2442
2443 /// Move the instruction back to its original position.
2444 void undo() override {
2445 LLVM_DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: moveBefore: " <<
*Inst << "\n"; } } while (false)
;
2446 Position.insert(Inst);
2447 }
2448 };
2449
2450 /// Set the operand of an instruction with a new value.
2451 class OperandSetter : public TypePromotionAction {
2452 /// Original operand of the instruction.
2453 Value *Origin;
2454
2455 /// Index of the modified instruction.
2456 unsigned Idx;
2457
2458 public:
2459 /// Set \p Idx operand of \p Inst with \p NewVal.
2460 OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
2461 : TypePromotionAction(Inst), Idx(Idx) {
2462 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)
2463 << "for:" << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
2464 << "with:" << *NewVal << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
;
2465 Origin = Inst->getOperand(Idx);
2466 Inst->setOperand(Idx, NewVal);
2467 }
2468
2469 /// Restore the original value of the instruction.
2470 void undo() override {
2471 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)
2472 << "for: " << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
2473 << "with: " << *Origin << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
;
2474 Inst->setOperand(Idx, Origin);
2475 }
2476 };
2477
2478 /// Hide the operands of an instruction.
2479 /// Do as if this instruction was not using any of its operands.
2480 class OperandsHider : public TypePromotionAction {
2481 /// The list of original operands.
2482 SmallVector<Value *, 4> OriginalValues;
2483
2484 public:
2485 /// Remove \p Inst from the uses of the operands of \p Inst.
2486 OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
2487 LLVM_DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: OperandsHider: " <<
*Inst << "\n"; } } while (false)
;
2488 unsigned NumOpnds = Inst->getNumOperands();
2489 OriginalValues.reserve(NumOpnds);
2490 for (unsigned It = 0; It < NumOpnds; ++It) {
2491 // Save the current operand.
2492 Value *Val = Inst->getOperand(It);
2493 OriginalValues.push_back(Val);
2494 // Set a dummy one.
2495 // We could use OperandSetter here, but that would imply an overhead
2496 // that we are not willing to pay.
2497 Inst->setOperand(It, UndefValue::get(Val->getType()));
2498 }
2499 }
2500
2501 /// Restore the original list of uses.
2502 void undo() override {
2503 LLVM_DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: OperandsHider: "
<< *Inst << "\n"; } } while (false)
;
2504 for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
2505 Inst->setOperand(It, OriginalValues[It]);
2506 }
2507 };
2508
2509 /// Build a truncate instruction.
2510 class TruncBuilder : public TypePromotionAction {
2511 Value *Val;
2512
2513 public:
2514 /// Build a truncate instruction of \p Opnd producing a \p Ty
2515 /// result.
2516 /// trunc Opnd to Ty.
2517 TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
2518 IRBuilder<> Builder(Opnd);
2519 Val = Builder.CreateTrunc(Opnd, Ty, "promoted");
2520 LLVM_DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: TruncBuilder: " <<
*Val << "\n"; } } while (false)
;
2521 }
2522
2523 /// Get the built value.
2524 Value *getBuiltValue() { return Val; }
2525
2526 /// Remove the built instruction.
2527 void undo() override {
2528 LLVM_DEBUG(dbgs() << "Undo: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: TruncBuilder: " <<
*Val << "\n"; } } while (false)
;
2529 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2530 IVal->eraseFromParent();
2531 }
2532 };
2533
2534 /// Build a sign extension instruction.
2535 class SExtBuilder : public TypePromotionAction {
2536 Value *Val;
2537
2538 public:
2539 /// Build a sign extension instruction of \p Opnd producing a \p Ty
2540 /// result.
2541 /// sext Opnd to Ty.
2542 SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2543 : TypePromotionAction(InsertPt) {
2544 IRBuilder<> Builder(InsertPt);
2545 Val = Builder.CreateSExt(Opnd, Ty, "promoted");
2546 LLVM_DEBUG(dbgs() << "Do: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: SExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2547 }
2548
2549 /// Get the built value.
2550 Value *getBuiltValue() { return Val; }
2551
2552 /// Remove the built instruction.
2553 void undo() override {
2554 LLVM_DEBUG(dbgs() << "Undo: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: SExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2555 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2556 IVal->eraseFromParent();
2557 }
2558 };
2559
2560 /// Build a zero extension instruction.
2561 class ZExtBuilder : public TypePromotionAction {
2562 Value *Val;
2563
2564 public:
2565 /// Build a zero extension instruction of \p Opnd producing a \p Ty
2566 /// result.
2567 /// zext Opnd to Ty.
2568 ZExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2569 : TypePromotionAction(InsertPt) {
2570 IRBuilder<> Builder(InsertPt);
2571 Val = Builder.CreateZExt(Opnd, Ty, "promoted");
2572 LLVM_DEBUG(dbgs() << "Do: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: ZExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2573 }
2574
2575 /// Get the built value.
2576 Value *getBuiltValue() { return Val; }
2577
2578 /// Remove the built instruction.
2579 void undo() override {
2580 LLVM_DEBUG(dbgs() << "Undo: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: ZExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2581 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2582 IVal->eraseFromParent();
2583 }
2584 };
2585
2586 /// Mutate an instruction to another type.
2587 class TypeMutator : public TypePromotionAction {
2588 /// Record the original type.
2589 Type *OrigTy;
2590
2591 public:
2592 /// Mutate the type of \p Inst into \p NewTy.
2593 TypeMutator(Instruction *Inst, Type *NewTy)
2594 : TypePromotionAction(Inst), OrigTy(Inst->getType()) {
2595 LLVM_DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
*Inst << " with " << *NewTy << "\n"; } } while
(false)
2596 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
*Inst << " with " << *NewTy << "\n"; } } while
(false)
;
2597 Inst->mutateType(NewTy);
2598 }
2599
2600 /// Mutate the instruction back to its original type.
2601 void undo() override {
2602 LLVM_DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
*Inst << " with " << *OrigTy << "\n"; } } while
(false)
2603 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
*Inst << " with " << *OrigTy << "\n"; } } while
(false)
;
2604 Inst->mutateType(OrigTy);
2605 }
2606 };
2607
2608 /// Replace the uses of an instruction by another instruction.
2609 class UsesReplacer : public TypePromotionAction {
2610 /// Helper structure to keep track of the replaced uses.
2611 struct InstructionAndIdx {
2612 /// The instruction using the instruction.
2613 Instruction *Inst;
2614
2615 /// The index where this instruction is used for Inst.
2616 unsigned Idx;
2617
2618 InstructionAndIdx(Instruction *Inst, unsigned Idx)
2619 : Inst(Inst), Idx(Idx) {}
2620 };
2621
2622 /// Keep track of the original uses (pair Instruction, Index).
2623 SmallVector<InstructionAndIdx, 4> OriginalUses;
2624 /// Keep track of the debug users.
2625 SmallVector<DbgValueInst *, 1> DbgValues;
2626
2627 using use_iterator = SmallVectorImpl<InstructionAndIdx>::iterator;
2628
2629 public:
2630 /// Replace all the use of \p Inst by \p New.
2631 UsesReplacer(Instruction *Inst, Value *New) : TypePromotionAction(Inst) {
2632 LLVM_DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *Newdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
*Inst << " with " << *New << "\n"; } } while
(false)
2633 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
*Inst << " with " << *New << "\n"; } } while
(false)
;
2634 // Record the original uses.
2635 for (Use &U : Inst->uses()) {
2636 Instruction *UserI = cast<Instruction>(U.getUser());
2637 OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo()));
2638 }
2639 // Record the debug uses separately. They are not in the instruction's
2640 // use list, but they are replaced by RAUW.
2641 findDbgValues(DbgValues, Inst);
2642
2643 // Now, we can replace the uses.
2644 Inst->replaceAllUsesWith(New);
2645 }
2646
2647 /// Reassign the original uses of Inst to Inst.
2648 void undo() override {
2649 LLVM_DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: UsersReplacer: "
<< *Inst << "\n"; } } while (false)
;
2650 for (use_iterator UseIt = OriginalUses.begin(),
2651 EndIt = OriginalUses.end();
2652 UseIt != EndIt; ++UseIt) {
2653 UseIt->Inst->setOperand(UseIt->Idx, Inst);
2654 }
2655 // RAUW has replaced all original uses with references to the new value,
2656 // including the debug uses. Since we are undoing the replacements,
2657 // the original debug uses must also be reinstated to maintain the
2658 // correctness and utility of debug value instructions.
2659 for (auto *DVI: DbgValues) {
2660 LLVMContext &Ctx = Inst->getType()->getContext();
2661 auto *MV = MetadataAsValue::get(Ctx, ValueAsMetadata::get(Inst));
2662 DVI->setOperand(0, MV);
2663 }
2664 }
2665 };
2666
2667 /// Remove an instruction from the IR.
2668 class InstructionRemover : public TypePromotionAction {
2669 /// Original position of the instruction.
2670 InsertionHandler Inserter;
2671
2672 /// Helper structure to hide all the link to the instruction. In other
2673 /// words, this helps to do as if the instruction was removed.
2674 OperandsHider Hider;
2675
2676 /// Keep track of the uses replaced, if any.
2677 UsesReplacer *Replacer = nullptr;
2678
2679 /// Keep track of instructions removed.
2680 SetOfInstrs &RemovedInsts;
2681
2682 public:
2683 /// Remove all reference of \p Inst and optionally replace all its
2684 /// uses with New.
2685 /// \p RemovedInsts Keep track of the instructions removed by this Action.
2686 /// \pre If !Inst->use_empty(), then New != nullptr
2687 InstructionRemover(Instruction *Inst, SetOfInstrs &RemovedInsts,
2688 Value *New = nullptr)
2689 : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
2690 RemovedInsts(RemovedInsts) {
2691 if (New)
2692 Replacer = new UsesReplacer(Inst, New);
2693 LLVM_DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: InstructionRemover: "
<< *Inst << "\n"; } } while (false)
;
2694 RemovedInsts.insert(Inst);
2695 /// The instructions removed here will be freed after completing
2696 /// optimizeBlock() for all blocks as we need to keep track of the
2697 /// removed instructions during promotion.
2698 Inst->removeFromParent();
2699 }
2700
2701 ~InstructionRemover() override { delete Replacer; }
2702
2703 /// Resurrect the instruction and reassign it to the proper uses if
2704 /// new value was provided when build this action.
2705 void undo() override {
2706 LLVM_DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: InstructionRemover: "
<< *Inst << "\n"; } } while (false)
;
2707 Inserter.insert(Inst);
2708 if (Replacer)
2709 Replacer->undo();
2710 Hider.undo();
2711 RemovedInsts.erase(Inst);
2712 }
2713 };
2714
2715public:
2716 /// Restoration point.
2717 /// The restoration point is a pointer to an action instead of an iterator
2718 /// because the iterator may be invalidated but not the pointer.
2719 using ConstRestorationPt = const TypePromotionAction *;
2720
2721 TypePromotionTransaction(SetOfInstrs &RemovedInsts)
2722 : RemovedInsts(RemovedInsts) {}
2723
2724 /// Advocate every changes made in that transaction.
2725 void commit();
2726
2727 /// Undo all the changes made after the given point.
2728 void rollback(ConstRestorationPt Point);
2729
2730 /// Get the current restoration point.
2731 ConstRestorationPt getRestorationPoint() const;
2732
2733 /// \name API for IR modification with state keeping to support rollback.
2734 /// @{
2735 /// Same as Instruction::setOperand.
2736 void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);
2737
2738 /// Same as Instruction::eraseFromParent.
2739 void eraseInstruction(Instruction *Inst, Value *NewVal = nullptr);
2740
2741 /// Same as Value::replaceAllUsesWith.
2742 void replaceAllUsesWith(Instruction *Inst, Value *New);
2743
2744 /// Same as Value::mutateType.
2745 void mutateType(Instruction *Inst, Type *NewTy);
2746
2747 /// Same as IRBuilder::createTrunc.
2748 Value *createTrunc(Instruction *Opnd, Type *Ty);
2749
2750 /// Same as IRBuilder::createSExt.
2751 Value *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);
2752
2753 /// Same as IRBuilder::createZExt.
2754 Value *createZExt(Instruction *Inst, Value *Opnd, Type *Ty);
2755
2756 /// Same as Instruction::moveBefore.
2757 void moveBefore(Instruction *Inst, Instruction *Before);
2758 /// @}
2759
2760private:
2761 /// The ordered list of actions made so far.
2762 SmallVector<std::unique_ptr<TypePromotionAction>, 16> Actions;
2763
2764 using CommitPt = SmallVectorImpl<std::unique_ptr<TypePromotionAction>>::iterator;
2765
2766 SetOfInstrs &RemovedInsts;
2767};
2768
2769} // end anonymous namespace
2770
2771void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
2772 Value *NewVal) {
2773 Actions.push_back(std::make_unique<TypePromotionTransaction::OperandSetter>(
2774 Inst, Idx, NewVal));
2775}
2776
2777void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
2778 Value *NewVal) {
2779 Actions.push_back(
2780 std::make_unique<TypePromotionTransaction::InstructionRemover>(
2781 Inst, RemovedInsts, NewVal));
2782}
2783
2784void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
2785 Value *New) {
2786 Actions.push_back(
2787 std::make_unique<TypePromotionTransaction::UsesReplacer>(Inst, New));
2788}
2789
2790void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
2791 Actions.push_back(
2792 std::make_unique<TypePromotionTransaction::TypeMutator>(Inst, NewTy));
2793}
2794
2795Value *TypePromotionTransaction::createTrunc(Instruction *Opnd,
2796 Type *Ty) {
2797 std::unique_ptr<TruncBuilder> Ptr(new TruncBuilder(Opnd, Ty));
2798 Value *Val = Ptr->getBuiltValue();
2799 Actions.push_back(std::move(Ptr));
2800 return Val;
2801}
2802
2803Value *TypePromotionTransaction::createSExt(Instruction *Inst,
2804 Value *Opnd, Type *Ty) {
2805 std::unique_ptr<SExtBuilder> Ptr(new SExtBuilder(Inst, Opnd, Ty));
2806 Value *Val = Ptr->getBuiltValue();
2807 Actions.push_back(std::move(Ptr));
2808 return Val;
2809}
2810
2811Value *TypePromotionTransaction::createZExt(Instruction *Inst,
2812 Value *Opnd, Type *Ty) {
2813 std::unique_ptr<ZExtBuilder> Ptr(new ZExtBuilder(Inst, Opnd, Ty));
2814 Value *Val = Ptr->getBuiltValue();
2815 Actions.push_back(std::move(Ptr));
2816 return Val;
2817}
2818
2819void TypePromotionTransaction::moveBefore(Instruction *Inst,
2820 Instruction *Before) {
2821 Actions.push_back(
2822 std::make_unique<TypePromotionTransaction::InstructionMoveBefore>(
2823 Inst, Before));
2824}
2825
2826TypePromotionTransaction::ConstRestorationPt
2827TypePromotionTransaction::getRestorationPoint() const {
2828 return !Actions.empty() ? Actions.back().get() : nullptr;
2829}
2830
2831void TypePromotionTransaction::commit() {
2832 for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt;
2833 ++It)
2834 (*It)->commit();
2835 Actions.clear();
2836}
2837
2838void TypePromotionTransaction::rollback(
2839 TypePromotionTransaction::ConstRestorationPt Point) {
2840 while (!Actions.empty() && Point != Actions.back().get()) {
2841 std::unique_ptr<TypePromotionAction> Curr = Actions.pop_back_val();
2842 Curr->undo();
2843 }
2844}
2845
2846namespace {
2847
2848/// A helper class for matching addressing modes.
2849///
2850/// This encapsulates the logic for matching the target-legal addressing modes.
2851class AddressingModeMatcher {
2852 SmallVectorImpl<Instruction*> &AddrModeInsts;
2853 const TargetLowering &TLI;
2854 const TargetRegisterInfo &TRI;
2855 const DataLayout &DL;
2856
2857 /// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
2858 /// the memory instruction that we're computing this address for.
2859 Type *AccessTy;
2860 unsigned AddrSpace;
2861 Instruction *MemoryInst;
2862
2863 /// This is the addressing mode that we're building up. This is
2864 /// part of the return value of this addressing mode matching stuff.
2865 ExtAddrMode &AddrMode;
2866
2867 /// The instructions inserted by other CodeGenPrepare optimizations.
2868 const SetOfInstrs &InsertedInsts;
2869
2870 /// A map from the instructions to their type before promotion.
2871 InstrToOrigTy &PromotedInsts;
2872
2873 /// The ongoing transaction where every action should be registered.
2874 TypePromotionTransaction &TPT;
2875
2876 // A GEP which has too large offset to be folded into the addressing mode.
2877 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP;
2878
2879 /// This is set to true when we should not do profitability checks.
2880 /// When true, IsProfitableToFoldIntoAddressingMode always returns true.
2881 bool IgnoreProfitability;
2882
2883 /// True if we are optimizing for size.
2884 bool OptSize;
2885
2886 ProfileSummaryInfo *PSI;
2887 BlockFrequencyInfo *BFI;
2888
2889 AddressingModeMatcher(
2890 SmallVectorImpl<Instruction *> &AMI, const TargetLowering &TLI,
2891 const TargetRegisterInfo &TRI, Type *AT, unsigned AS, Instruction *MI,
2892 ExtAddrMode &AM, const SetOfInstrs &InsertedInsts,
2893 InstrToOrigTy &PromotedInsts, TypePromotionTransaction &TPT,
2894 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
2895 bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI)
2896 : AddrModeInsts(AMI), TLI(TLI), TRI(TRI),
2897 DL(MI->getModule()->getDataLayout()), AccessTy(AT), AddrSpace(AS),
2898 MemoryInst(MI), AddrMode(AM), InsertedInsts(InsertedInsts),
2899 PromotedInsts(PromotedInsts), TPT(TPT), LargeOffsetGEP(LargeOffsetGEP),
2900 OptSize(OptSize), PSI(PSI), BFI(BFI) {
2901 IgnoreProfitability = false;
2902 }
2903
2904public:
2905 /// Find the maximal addressing mode that a load/store of V can fold,
2906 /// give an access type of AccessTy. This returns a list of involved
2907 /// instructions in AddrModeInsts.
2908 /// \p InsertedInsts The instructions inserted by other CodeGenPrepare
2909 /// optimizations.
2910 /// \p PromotedInsts maps the instructions to their type before promotion.
2911 /// \p The ongoing transaction where every action should be registered.
2912 static ExtAddrMode
2913 Match(Value *V, Type *AccessTy, unsigned AS, Instruction *MemoryInst,
2914 SmallVectorImpl<Instruction *> &AddrModeInsts,
2915 const TargetLowering &TLI, const TargetRegisterInfo &TRI,
2916 const SetOfInstrs &InsertedInsts, InstrToOrigTy &PromotedInsts,
2917 TypePromotionTransaction &TPT,
2918 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
2919 bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) {
2920 ExtAddrMode Result;
2921
2922 bool Success = AddressingModeMatcher(AddrModeInsts, TLI, TRI, AccessTy, AS,
2923 MemoryInst, Result, InsertedInsts,
2924 PromotedInsts, TPT, LargeOffsetGEP,
2925 OptSize, PSI, BFI)
2926 .matchAddr(V, 0);
2927 (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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2927, __PRETTY_FUNCTION__))
;
2928 return Result;
2929 }
2930
2931private:
2932 bool matchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
2933 bool matchAddr(Value *Addr, unsigned Depth);
2934 bool matchOperationAddr(User *AddrInst, unsigned Opcode, unsigned Depth,
2935 bool *MovedAway = nullptr);
2936 bool isProfitableToFoldIntoAddressingMode(Instruction *I,
2937 ExtAddrMode &AMBefore,
2938 ExtAddrMode &AMAfter);
2939 bool valueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
2940 bool isPromotionProfitable(unsigned NewCost, unsigned OldCost,
2941 Value *PromotedOperand) const;
2942};
2943
2944class PhiNodeSet;
2945
2946/// An iterator for PhiNodeSet.
2947class PhiNodeSetIterator {
2948 PhiNodeSet * const Set;
2949 size_t CurrentIndex = 0;
2950
2951public:
2952 /// The constructor. Start should point to either a valid element, or be equal
2953 /// to the size of the underlying SmallVector of the PhiNodeSet.
2954 PhiNodeSetIterator(PhiNodeSet * const Set, size_t Start);
2955 PHINode * operator*() const;
2956 PhiNodeSetIterator& operator++();
2957 bool operator==(const PhiNodeSetIterator &RHS) const;
2958 bool operator!=(const PhiNodeSetIterator &RHS) const;
2959};
2960
2961/// Keeps a set of PHINodes.
2962///
2963/// This is a minimal set implementation for a specific use case:
2964/// It is very fast when there are very few elements, but also provides good
2965/// performance when there are many. It is similar to SmallPtrSet, but also
2966/// provides iteration by insertion order, which is deterministic and stable
2967/// across runs. It is also similar to SmallSetVector, but provides removing
2968/// elements in O(1) time. This is achieved by not actually removing the element
2969/// from the underlying vector, so comes at the cost of using more memory, but
2970/// that is fine, since PhiNodeSets are used as short lived objects.
2971class PhiNodeSet {
2972 friend class PhiNodeSetIterator;
2973
2974 using MapType = SmallDenseMap<PHINode *, size_t, 32>;
2975 using iterator = PhiNodeSetIterator;
2976
2977 /// Keeps the elements in the order of their insertion in the underlying
2978 /// vector. To achieve constant time removal, it never deletes any element.
2979 SmallVector<PHINode *, 32> NodeList;
2980
2981 /// Keeps the elements in the underlying set implementation. This (and not the
2982 /// NodeList defined above) is the source of truth on whether an element
2983 /// is actually in the collection.
2984 MapType NodeMap;
2985
2986 /// Points to the first valid (not deleted) element when the set is not empty
2987 /// and the value is not zero. Equals to the size of the underlying vector
2988 /// when the set is empty. When the value is 0, as in the beginning, the
2989 /// first element may or may not be valid.
2990 size_t FirstValidElement = 0;
2991
2992public:
2993 /// Inserts a new element to the collection.
2994 /// \returns true if the element is actually added, i.e. was not in the
2995 /// collection before the operation.
2996 bool insert(PHINode *Ptr) {
2997 if (NodeMap.insert(std::make_pair(Ptr, NodeList.size())).second) {
2998 NodeList.push_back(Ptr);
2999 return true;
3000 }
3001 return false;
3002 }
3003
3004 /// Removes the element from the collection.
3005 /// \returns whether the element is actually removed, i.e. was in the
3006 /// collection before the operation.
3007 bool erase(PHINode *Ptr) {
3008 auto it = NodeMap.find(Ptr);
3009 if (it != NodeMap.end()) {
3010 NodeMap.erase(Ptr);
3011 SkipRemovedElements(FirstValidElement);
3012 return true;
3013 }
3014 return false;
3015 }
3016
3017 /// Removes all elements and clears the collection.
3018 void clear() {
3019 NodeMap.clear();
3020 NodeList.clear();
3021 FirstValidElement = 0;
3022 }
3023
3024 /// \returns an iterator that will iterate the elements in the order of
3025 /// insertion.
3026 iterator begin() {
3027 if (FirstValidElement == 0)
3028 SkipRemovedElements(FirstValidElement);
3029 return PhiNodeSetIterator(this, FirstValidElement);
3030 }
3031
3032 /// \returns an iterator that points to the end of the collection.
3033 iterator end() { return PhiNodeSetIterator(this, NodeList.size()); }
3034
3035 /// Returns the number of elements in the collection.
3036 size_t size() const {
3037 return NodeMap.size();
3038 }
3039
3040 /// \returns 1 if the given element is in the collection, and 0 if otherwise.
3041 size_t count(PHINode *Ptr) const {
3042 return NodeMap.count(Ptr);
3043 }
3044
3045private:
3046 /// Updates the CurrentIndex so that it will point to a valid element.
3047 ///
3048 /// If the element of NodeList at CurrentIndex is valid, it does not
3049 /// change it. If there are no more valid elements, it updates CurrentIndex
3050 /// to point to the end of the NodeList.
3051 void SkipRemovedElements(size_t &CurrentIndex) {
3052 while (CurrentIndex < NodeList.size()) {
3053 auto it = NodeMap.find(NodeList[CurrentIndex]);
3054 // If the element has been deleted and added again later, NodeMap will
3055 // point to a different index, so CurrentIndex will still be invalid.
3056 if (it != NodeMap.end() && it->second == CurrentIndex)
3057 break;
3058 ++CurrentIndex;
3059 }
3060 }
3061};
3062
3063PhiNodeSetIterator::PhiNodeSetIterator(PhiNodeSet *const Set, size_t Start)
3064 : Set(Set), CurrentIndex(Start) {}
3065
3066PHINode * PhiNodeSetIterator::operator*() const {
3067 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3068, __PRETTY_FUNCTION__))
3068 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3068, __PRETTY_FUNCTION__))
;
3069 return Set->NodeList[CurrentIndex];
3070}
3071
3072PhiNodeSetIterator& PhiNodeSetIterator::operator++() {
3073 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3074, __PRETTY_FUNCTION__))
3074 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3074, __PRETTY_FUNCTION__))
;
3075 ++CurrentIndex;
3076 Set->SkipRemovedElements(CurrentIndex);
3077 return *this;
3078}
3079
3080bool PhiNodeSetIterator::operator==(const PhiNodeSetIterator &RHS) const {
3081 return CurrentIndex == RHS.CurrentIndex;
3082}
3083
3084bool PhiNodeSetIterator::operator!=(const PhiNodeSetIterator &RHS) const {
3085 return !((*this) == RHS);
3086}
3087
3088/// Keep track of simplification of Phi nodes.
3089/// Accept the set of all phi nodes and erase phi node from this set
3090/// if it is simplified.
3091class SimplificationTracker {
3092 DenseMap<Value *, Value *> Storage;
3093 const SimplifyQuery &SQ;
3094 // Tracks newly created Phi nodes. The elements are iterated by insertion
3095 // order.
3096 PhiNodeSet AllPhiNodes;
3097 // Tracks newly created Select nodes.
3098 SmallPtrSet<SelectInst *, 32> AllSelectNodes;
3099
3100public:
3101 SimplificationTracker(const SimplifyQuery &sq)
3102 : SQ(sq) {}
3103
3104 Value *Get(Value *V) {
3105 do {
3106 auto SV = Storage.find(V);
3107 if (SV == Storage.end())
3108 return V;
3109 V = SV->second;
3110 } while (true);
3111 }
3112
3113 Value *Simplify(Value *Val) {
3114 SmallVector<Value *, 32> WorkList;
3115 SmallPtrSet<Value *, 32> Visited;
3116 WorkList.push_back(Val);
3117 while (!WorkList.empty()) {
3118 auto P = WorkList.pop_back_val();
3119 if (!Visited.insert(P).second)
3120 continue;
3121 if (auto *PI = dyn_cast<Instruction>(P))
3122 if (Value *V = SimplifyInstruction(cast<Instruction>(PI), SQ)) {
3123 for (auto *U : PI->users())
3124 WorkList.push_back(cast<Value>(U));
3125 Put(PI, V);
3126 PI->replaceAllUsesWith(V);
3127 if (auto *PHI = dyn_cast<PHINode>(PI))
3128 AllPhiNodes.erase(PHI);
3129 if (auto *Select = dyn_cast<SelectInst>(PI))
3130 AllSelectNodes.erase(Select);
3131 PI->eraseFromParent();
3132 }
3133 }
3134 return Get(Val);
3135 }
3136
3137 void Put(Value *From, Value *To) {
3138 Storage.insert({ From, To });
3139 }
3140
3141 void ReplacePhi(PHINode *From, PHINode *To) {
3142 Value* OldReplacement = Get(From);
3143 while (OldReplacement != From) {
3144 From = To;
3145 To = dyn_cast<PHINode>(OldReplacement);
3146 OldReplacement = Get(From);
3147 }
3148 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3148, __PRETTY_FUNCTION__))
;
3149 Put(From, To);
3150 From->replaceAllUsesWith(To);
3151 AllPhiNodes.erase(From);
3152 From->eraseFromParent();
3153 }
3154
3155 PhiNodeSet& newPhiNodes() { return AllPhiNodes; }
3156
3157 void insertNewPhi(PHINode *PN) { AllPhiNodes.insert(PN); }
3158
3159 void insertNewSelect(SelectInst *SI) { AllSelectNodes.insert(SI); }
3160
3161 unsigned countNewPhiNodes() const { return AllPhiNodes.size(); }
3162
3163 unsigned countNewSelectNodes() const { return AllSelectNodes.size(); }
3164
3165 void destroyNewNodes(Type *CommonType) {
3166 // For safe erasing, replace the uses with dummy value first.
3167 auto Dummy = UndefValue::get(CommonType);
3168 for (auto I : AllPhiNodes) {
3169 I->replaceAllUsesWith(Dummy);
3170 I->eraseFromParent();
3171 }
3172 AllPhiNodes.clear();
3173 for (auto I : AllSelectNodes) {
3174 I->replaceAllUsesWith(Dummy);
3175 I->eraseFromParent();
3176 }
3177 AllSelectNodes.clear();
3178 }
3179};
3180
3181/// A helper class for combining addressing modes.
3182class AddressingModeCombiner {
3183 typedef DenseMap<Value *, Value *> FoldAddrToValueMapping;
3184 typedef std::pair<PHINode *, PHINode *> PHIPair;
3185
3186private:
3187 /// The addressing modes we've collected.
3188 SmallVector<ExtAddrMode, 16> AddrModes;
3189
3190 /// The field in which the AddrModes differ, when we have more than one.
3191 ExtAddrMode::FieldName DifferentField = ExtAddrMode::NoField;
3192
3193 /// Are the AddrModes that we have all just equal to their original values?
3194 bool AllAddrModesTrivial = true;
3195
3196 /// Common Type for all different fields in addressing modes.
3197 Type *CommonType;
3198
3199 /// SimplifyQuery for simplifyInstruction utility.
3200 const SimplifyQuery &SQ;
3201
3202 /// Original Address.
3203 Value *Original;
3204
3205public:
3206 AddressingModeCombiner(const SimplifyQuery &_SQ, Value *OriginalValue)
3207 : CommonType(nullptr), SQ(_SQ), Original(OriginalValue) {}
3208
3209 /// Get the combined AddrMode
3210 const ExtAddrMode &getAddrMode() const {
3211 return AddrModes[0];
3212 }
3213
3214 /// Add a new AddrMode if it's compatible with the AddrModes we already
3215 /// have.
3216 /// \return True iff we succeeded in doing so.
3217 bool addNewAddrMode(ExtAddrMode &NewAddrMode) {
3218 // Take note of if we have any non-trivial AddrModes, as we need to detect
3219 // when all AddrModes are trivial as then we would introduce a phi or select
3220 // which just duplicates what's already there.
3221 AllAddrModesTrivial = AllAddrModesTrivial && NewAddrMode.isTrivial();
3222
3223 // If this is the first addrmode then everything is fine.
3224 if (AddrModes.empty()) {
3225 AddrModes.emplace_back(NewAddrMode);
3226 return true;
3227 }
3228
3229 // Figure out how different this is from the other address modes, which we
3230 // can do just by comparing against the first one given that we only care
3231 // about the cumulative difference.
3232 ExtAddrMode::FieldName ThisDifferentField =
3233 AddrModes[0].compare(NewAddrMode);
3234 if (DifferentField == ExtAddrMode::NoField)
3235 DifferentField = ThisDifferentField;
3236 else if (DifferentField != ThisDifferentField)
3237 DifferentField = ExtAddrMode::MultipleFields;
3238
3239 // If NewAddrMode differs in more than one dimension we cannot handle it.
3240 bool CanHandle = DifferentField != ExtAddrMode::MultipleFields;
3241
3242 // If Scale Field is different then we reject.
3243 CanHandle = CanHandle && DifferentField != ExtAddrMode::ScaleField;
3244
3245 // We also must reject the case when base offset is different and
3246 // scale reg is not null, we cannot handle this case due to merge of
3247 // different offsets will be used as ScaleReg.
3248 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseOffsField ||
3249 !NewAddrMode.ScaledReg);
3250
3251 // We also must reject the case when GV is different and BaseReg installed
3252 // due to we want to use base reg as a merge of GV values.
3253 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseGVField ||
3254 !NewAddrMode.HasBaseReg);
3255
3256 // Even if NewAddMode is the same we still need to collect it due to
3257 // original value is different. And later we will need all original values
3258 // as anchors during finding the common Phi node.
3259 if (CanHandle)
3260 AddrModes.emplace_back(NewAddrMode);
3261 else
3262 AddrModes.clear();
3263
3264 return CanHandle;
3265 }
3266
3267 /// Combine the addressing modes we've collected into a single
3268 /// addressing mode.
3269 /// \return True iff we successfully combined them or we only had one so
3270 /// didn't need to combine them anyway.
3271 bool combineAddrModes() {
3272 // If we have no AddrModes then they can't be combined.
3273 if (AddrModes.size() == 0)
3274 return false;
3275
3276 // A single AddrMode can trivially be combined.
3277 if (AddrModes.size() == 1 || DifferentField == ExtAddrMode::NoField)
3278 return true;
3279
3280 // If the AddrModes we collected are all just equal to the value they are
3281 // derived from then combining them wouldn't do anything useful.
3282 if (AllAddrModesTrivial)
3283 return false;
3284
3285 if (!addrModeCombiningAllowed())
3286 return false;
3287
3288 // Build a map between <original value, basic block where we saw it> to
3289 // value of base register.
3290 // Bail out if there is no common type.
3291 FoldAddrToValueMapping Map;
3292 if (!initializeMap(Map))
3293 return false;
3294
3295 Value *CommonValue = findCommon(Map);
3296 if (CommonValue)
3297 AddrModes[0].SetCombinedField(DifferentField, CommonValue, AddrModes);
3298 return CommonValue != nullptr;
3299 }
3300
3301private:
3302 /// Initialize Map with anchor values. For address seen
3303 /// we set the value of different field saw in this address.
3304 /// At the same time we find a common type for different field we will
3305 /// use to create new Phi/Select nodes. Keep it in CommonType field.
3306 /// Return false if there is no common type found.
3307 bool initializeMap(FoldAddrToValueMapping &Map) {
3308 // Keep track of keys where the value is null. We will need to replace it
3309 // with constant null when we know the common type.
3310 SmallVector<Value *, 2> NullValue;
3311 Type *IntPtrTy = SQ.DL.getIntPtrType(AddrModes[0].OriginalValue->getType());
3312 for (auto &AM : AddrModes) {
3313 Value *DV = AM.GetFieldAsValue(DifferentField, IntPtrTy);
3314 if (DV) {
3315 auto *Type = DV->getType();
3316 if (CommonType && CommonType != Type)
3317 return false;
3318 CommonType = Type;
3319 Map[AM.OriginalValue] = DV;
3320 } else {
3321 NullValue.push_back(AM.OriginalValue);
3322 }
3323 }
3324 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3324, __PRETTY_FUNCTION__))
;
3325 for (auto *V : NullValue)
3326 Map[V] = Constant::getNullValue(CommonType);
3327 return true;
3328 }
3329
3330 /// We have mapping between value A and other value B where B was a field in
3331 /// addressing mode represented by A. Also we have an original value C
3332 /// representing an address we start with. Traversing from C through phi and
3333 /// selects we ended up with A's in a map. This utility function tries to find
3334 /// a value V which is a field in addressing mode C and traversing through phi
3335 /// nodes and selects we will end up in corresponded values B in a map.
3336 /// The utility will create a new Phi/Selects if needed.
3337 // The simple example looks as follows:
3338 // BB1:
3339 // p1 = b1 + 40
3340 // br cond BB2, BB3
3341 // BB2:
3342 // p2 = b2 + 40
3343 // br BB3
3344 // BB3:
3345 // p = phi [p1, BB1], [p2, BB2]
3346 // v = load p
3347 // Map is
3348 // p1 -> b1
3349 // p2 -> b2
3350 // Request is
3351 // p -> ?
3352 // The function tries to find or build phi [b1, BB1], [b2, BB2] in BB3.
3353 Value *findCommon(FoldAddrToValueMapping &Map) {
3354 // Tracks the simplification of newly created phi nodes. The reason we use
3355 // this mapping is because we will add new created Phi nodes in AddrToBase.
3356 // Simplification of Phi nodes is recursive, so some Phi node may
3357 // be simplified after we added it to AddrToBase. In reality this
3358 // simplification is possible only if original phi/selects were not
3359 // simplified yet.
3360 // Using this mapping we can find the current value in AddrToBase.
3361 SimplificationTracker ST(SQ);
3362
3363 // First step, DFS to create PHI nodes for all intermediate blocks.
3364 // Also fill traverse order for the second step.
3365 SmallVector<Value *, 32> TraverseOrder;
3366 InsertPlaceholders(Map, TraverseOrder, ST);
3367
3368 // Second Step, fill new nodes by merged values and simplify if possible.
3369 FillPlaceholders(Map, TraverseOrder, ST);
3370
3371 if (!AddrSinkNewSelects && ST.countNewSelectNodes() > 0) {
3372 ST.destroyNewNodes(CommonType);
3373 return nullptr;
3374 }
3375
3376 // Now we'd like to match New Phi nodes to existed ones.
3377 unsigned PhiNotMatchedCount = 0;
3378 if (!MatchPhiSet(ST, AddrSinkNewPhis, PhiNotMatchedCount)) {
3379 ST.destroyNewNodes(CommonType);
3380 return nullptr;
3381 }
3382
3383 auto *Result = ST.Get(Map.find(Original)->second);
3384 if (Result) {
3385 NumMemoryInstsPhiCreated += ST.countNewPhiNodes() + PhiNotMatchedCount;
3386 NumMemoryInstsSelectCreated += ST.countNewSelectNodes();
3387 }
3388 return Result;
3389 }
3390
3391 /// Try to match PHI node to Candidate.
3392 /// Matcher tracks the matched Phi nodes.
3393 bool MatchPhiNode(PHINode *PHI, PHINode *Candidate,
3394 SmallSetVector<PHIPair, 8> &Matcher,
3395 PhiNodeSet &PhiNodesToMatch) {
3396 SmallVector<PHIPair, 8> WorkList;
3397 Matcher.insert({ PHI, Candidate });
3398 SmallSet<PHINode *, 8> MatchedPHIs;
3399 MatchedPHIs.insert(PHI);
3400 WorkList.push_back({ PHI, Candidate });
3401 SmallSet<PHIPair, 8> Visited;
3402 while (!WorkList.empty()) {
3403 auto Item = WorkList.pop_back_val();
3404 if (!Visited.insert(Item).second)
3405 continue;
3406 // We iterate over all incoming values to Phi to compare them.
3407 // If values are different and both of them Phi and the first one is a
3408 // Phi we added (subject to match) and both of them is in the same basic
3409 // block then we can match our pair if values match. So we state that
3410 // these values match and add it to work list to verify that.
3411 for (auto B : Item.first->blocks()) {
3412 Value *FirstValue = Item.first->getIncomingValueForBlock(B);
3413 Value *SecondValue = Item.second->getIncomingValueForBlock(B);
3414 if (FirstValue == SecondValue)
3415 continue;
3416
3417 PHINode *FirstPhi = dyn_cast<PHINode>(FirstValue);
3418 PHINode *SecondPhi = dyn_cast<PHINode>(SecondValue);
3419
3420 // One of them is not Phi or
3421 // The first one is not Phi node from the set we'd like to match or
3422 // Phi nodes from different basic blocks then
3423 // we will not be able to match.
3424 if (!FirstPhi || !SecondPhi || !PhiNodesToMatch.count(FirstPhi) ||
3425 FirstPhi->getParent() != SecondPhi->getParent())
3426 return false;
3427
3428 // If we already matched them then continue.
3429 if (Matcher.count({ FirstPhi, SecondPhi }))
3430 continue;
3431 // So the values are different and does not match. So we need them to
3432 // match. (But we register no more than one match per PHI node, so that
3433 // we won't later try to replace them twice.)
3434 if (MatchedPHIs.insert(FirstPhi).second)
3435 Matcher.insert({ FirstPhi, SecondPhi });
3436 // But me must check it.
3437 WorkList.push_back({ FirstPhi, SecondPhi });
3438 }
3439 }
3440 return true;
3441 }
3442
3443 /// For the given set of PHI nodes (in the SimplificationTracker) try
3444 /// to find their equivalents.
3445 /// Returns false if this matching fails and creation of new Phi is disabled.
3446 bool MatchPhiSet(SimplificationTracker &ST, bool AllowNewPhiNodes,
3447 unsigned &PhiNotMatchedCount) {
3448 // Matched and PhiNodesToMatch iterate their elements in a deterministic
3449 // order, so the replacements (ReplacePhi) are also done in a deterministic
3450 // order.
3451 SmallSetVector<PHIPair, 8> Matched;
3452 SmallPtrSet<PHINode *, 8> WillNotMatch;
3453 PhiNodeSet &PhiNodesToMatch = ST.newPhiNodes();
3454 while (PhiNodesToMatch.size()) {
3455 PHINode *PHI = *PhiNodesToMatch.begin();
3456
3457 // Add us, if no Phi nodes in the basic block we do not match.
3458 WillNotMatch.clear();
3459 WillNotMatch.insert(PHI);
3460
3461 // Traverse all Phis until we found equivalent or fail to do that.
3462 bool IsMatched = false;
3463 for (auto &P : PHI->getParent()->phis()) {
3464 if (&P == PHI)
3465 continue;
3466 if ((IsMatched = MatchPhiNode(PHI, &P, Matched, PhiNodesToMatch)))
3467 break;
3468 // If it does not match, collect all Phi nodes from matcher.
3469 // if we end up with no match, them all these Phi nodes will not match
3470 // later.
3471 for (auto M : Matched)
3472 WillNotMatch.insert(M.first);
3473 Matched.clear();
3474 }
3475 if (IsMatched) {
3476 // Replace all matched values and erase them.
3477 for (auto MV : Matched)
3478 ST.ReplacePhi(MV.first, MV.second);
3479 Matched.clear();
3480 continue;
3481 }
3482 // If we are not allowed to create new nodes then bail out.
3483 if (!AllowNewPhiNodes)
3484 return false;
3485 // Just remove all seen values in matcher. They will not match anything.
3486 PhiNotMatchedCount += WillNotMatch.size();
3487 for (auto *P : WillNotMatch)
3488 PhiNodesToMatch.erase(P);
3489 }
3490 return true;
3491 }
3492 /// Fill the placeholders with values from predecessors and simplify them.
3493 void FillPlaceholders(FoldAddrToValueMapping &Map,
3494 SmallVectorImpl<Value *> &TraverseOrder,
3495 SimplificationTracker &ST) {
3496 while (!TraverseOrder.empty()) {
3497 Value *Current = TraverseOrder.pop_back_val();
3498 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3498, __PRETTY_FUNCTION__))
;
3499 Value *V = Map[Current];
3500
3501 if (SelectInst *Select = dyn_cast<SelectInst>(V)) {
3502 // CurrentValue also must be Select.
3503 auto *CurrentSelect = cast<SelectInst>(Current);
3504 auto *TrueValue = CurrentSelect->getTrueValue();
3505 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3505, __PRETTY_FUNCTION__))
;
3506 Select->setTrueValue(ST.Get(Map[TrueValue]));
3507 auto *FalseValue = CurrentSelect->getFalseValue();
3508 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3508, __PRETTY_FUNCTION__))
;
3509 Select->setFalseValue(ST.Get(Map[FalseValue]));
3510 } else {
3511 // Must be a Phi node then.
3512 auto *PHI = cast<PHINode>(V);
3513 // Fill the Phi node with values from predecessors.
3514 for (auto B : predecessors(PHI->getParent())) {
3515 Value *PV = cast<PHINode>(Current)->getIncomingValueForBlock(B);
3516 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3516, __PRETTY_FUNCTION__))
;
3517 PHI->addIncoming(ST.Get(Map[PV]), B);
3518 }
3519 }
3520 Map[Current] = ST.Simplify(V);
3521 }
3522 }
3523
3524 /// Starting from original value recursively iterates over def-use chain up to
3525 /// known ending values represented in a map. For each traversed phi/select
3526 /// inserts a placeholder Phi or Select.
3527 /// Reports all new created Phi/Select nodes by adding them to set.
3528 /// Also reports and order in what values have been traversed.
3529 void InsertPlaceholders(FoldAddrToValueMapping &Map,
3530 SmallVectorImpl<Value *> &TraverseOrder,
3531 SimplificationTracker &ST) {
3532 SmallVector<Value *, 32> Worklist;
3533 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3534, __PRETTY_FUNCTION__))
3534 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3534, __PRETTY_FUNCTION__))
;
3535 auto *Dummy = UndefValue::get(CommonType);
3536 Worklist.push_back(Original);
3537 while (!Worklist.empty()) {
3538 Value *Current = Worklist.pop_back_val();
3539 // if it is already visited or it is an ending value then skip it.
3540 if (Map.find(Current) != Map.end())
3541 continue;
3542 TraverseOrder.push_back(Current);
3543
3544 // CurrentValue must be a Phi node or select. All others must be covered
3545 // by anchors.
3546 if (SelectInst *CurrentSelect = dyn_cast<SelectInst>(Current)) {
3547 // Is it OK to get metadata from OrigSelect?!
3548 // Create a Select placeholder with dummy value.
3549 SelectInst *Select = SelectInst::Create(
3550 CurrentSelect->getCondition(), Dummy, Dummy,
3551 CurrentSelect->getName(), CurrentSelect, CurrentSelect);
3552 Map[Current] = Select;
3553 ST.insertNewSelect(Select);
3554 // We are interested in True and False values.
3555 Worklist.push_back(CurrentSelect->getTrueValue());
3556 Worklist.push_back(CurrentSelect->getFalseValue());
3557 } else {
3558 // It must be a Phi node then.
3559 PHINode *CurrentPhi = cast<PHINode>(Current);
3560 unsigned PredCount = CurrentPhi->getNumIncomingValues();
3561 PHINode *PHI =
3562 PHINode::Create(CommonType, PredCount, "sunk_phi", CurrentPhi);
3563 Map[Current] = PHI;
3564 ST.insertNewPhi(PHI);
3565 for (Value *P : CurrentPhi->incoming_values())
3566 Worklist.push_back(P);
3567 }
3568 }
3569 }
3570
3571 bool addrModeCombiningAllowed() {
3572 if (DisableComplexAddrModes)
3573 return false;
3574 switch (DifferentField) {
3575 default:
3576 return false;
3577 case ExtAddrMode::BaseRegField:
3578 return AddrSinkCombineBaseReg;
3579 case ExtAddrMode::BaseGVField:
3580 return AddrSinkCombineBaseGV;
3581 case ExtAddrMode::BaseOffsField:
3582 return AddrSinkCombineBaseOffs;
3583 case ExtAddrMode::ScaledRegField:
3584 return AddrSinkCombineScaledReg;
3585 }
3586 }
3587};
3588} // end anonymous namespace
3589
3590/// Try adding ScaleReg*Scale to the current addressing mode.
3591/// Return true and update AddrMode if this addr mode is legal for the target,
3592/// false if not.
3593bool AddressingModeMatcher::matchScaledValue(Value *ScaleReg, int64_t Scale,
3594 unsigned Depth) {
3595 // If Scale is 1, then this is the same as adding ScaleReg to the addressing
3596 // mode. Just process that directly.
3597 if (Scale == 1)
3598 return matchAddr(ScaleReg, Depth);
3599
3600 // If the scale is 0, it takes nothing to add this.
3601 if (Scale == 0)
3602 return true;
3603
3604 // If we already have a scale of this value, we can add to it, otherwise, we
3605 // need an available scale field.
3606 if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
3607 return false;
3608
3609 ExtAddrMode TestAddrMode = AddrMode;
3610
3611 // Add scale to turn X*4+X*3 -> X*7. This could also do things like
3612 // [A+B + A*7] -> [B+A*8].
3613 TestAddrMode.Scale += Scale;
3614 TestAddrMode.ScaledReg = ScaleReg;
3615
3616 // If the new address isn't legal, bail out.
3617 if (!TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace))
3618 return false;
3619
3620 // It was legal, so commit it.
3621 AddrMode = TestAddrMode;
3622
3623 // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
3624 // to see if ScaleReg is actually X+C. If so, we can turn this into adding
3625 // X*Scale + C*Scale to addr mode.
3626 ConstantInt *CI = nullptr; Value *AddLHS = nullptr;
3627 if (isa<Instruction>(ScaleReg) && // not a constant expr.
3628 match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI)))) {
3629 TestAddrMode.InBounds = false;
3630 TestAddrMode.ScaledReg = AddLHS;
3631 TestAddrMode.BaseOffs += CI->getSExtValue()*TestAddrMode.Scale;
3632
3633 // If this addressing mode is legal, commit it and remember that we folded
3634 // this instruction.
3635 if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace)) {
3636 AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
3637 AddrMode = TestAddrMode;
3638 return true;
3639 }
3640 }
3641
3642 // Otherwise, not (x+c)*scale, just return what we have.
3643 return true;
3644}
3645
3646/// This is a little filter, which returns true if an addressing computation
3647/// involving I might be folded into a load/store accessing it.
3648/// This doesn't need to be perfect, but needs to accept at least
3649/// the set of instructions that MatchOperationAddr can.
3650static bool MightBeFoldableInst(Instruction *I) {
3651 switch (I->getOpcode()) {
3652 case Instruction::BitCast:
3653 case Instruction::AddrSpaceCast:
3654 // Don't touch identity bitcasts.
3655 if (I->getType() == I->getOperand(0)->getType())
3656 return false;
3657 return I->getType()->isIntOrPtrTy();
3658 case Instruction::PtrToInt:
3659 // PtrToInt is always a noop, as we know that the int type is pointer sized.
3660 return true;
3661 case Instruction::IntToPtr:
3662 // We know the input is intptr_t, so this is foldable.
3663 return true;
3664 case Instruction::Add:
3665 return true;
3666 case Instruction::Mul:
3667 case Instruction::Shl:
3668 // Can only handle X*C and X << C.
3669 return isa<ConstantInt>(I->getOperand(1));
3670 case Instruction::GetElementPtr:
3671 return true;
3672 default:
3673 return false;
3674 }
3675}
3676
3677/// Check whether or not \p Val is a legal instruction for \p TLI.
3678/// \note \p Val is assumed to be the product of some type promotion.
3679/// Therefore if \p Val has an undefined state in \p TLI, this is assumed
3680/// to be legal, as the non-promoted value would have had the same state.
3681static bool isPromotedInstructionLegal(const TargetLowering &TLI,
3682 const DataLayout &DL, Value *Val) {
3683 Instruction *PromotedInst = dyn_cast<Instruction>(Val);
3684 if (!PromotedInst)
3685 return false;
3686 int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
3687 // If the ISDOpcode is undefined, it was undefined before the promotion.
3688 if (!ISDOpcode)
3689 return true;
3690 // Otherwise, check if the promoted instruction is legal or not.
3691 return TLI.isOperationLegalOrCustom(
3692 ISDOpcode, TLI.getValueType(DL, PromotedInst->getType()));
3693}
3694
3695namespace {
3696
3697/// Hepler class to perform type promotion.
3698class TypePromotionHelper {
3699 /// Utility function to add a promoted instruction \p ExtOpnd to
3700 /// \p PromotedInsts and record the type of extension we have seen.
3701 static void addPromotedInst(InstrToOrigTy &PromotedInsts,
3702 Instruction *ExtOpnd,
3703 bool IsSExt) {
3704 ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
3705 InstrToOrigTy::iterator It = PromotedInsts.find(ExtOpnd);
3706 if (It != PromotedInsts.end()) {
3707 // If the new extension is same as original, the information in
3708 // PromotedInsts[ExtOpnd] is still correct.
3709 if (It->second.getInt() == ExtTy)
3710 return;
3711
3712 // Now the new extension is different from old extension, we make
3713 // the type information invalid by setting extension type to
3714 // BothExtension.
3715 ExtTy = BothExtension;
3716 }
3717 PromotedInsts[ExtOpnd] = TypeIsSExt(ExtOpnd->getType(), ExtTy);
3718 }
3719
3720 /// Utility function to query the original type of instruction \p Opnd
3721 /// with a matched extension type. If the extension doesn't match, we
3722 /// cannot use the information we had on the original type.
3723 /// BothExtension doesn't match any extension type.
3724 static const Type *getOrigType(const InstrToOrigTy &PromotedInsts,
3725 Instruction *Opnd,
3726 bool IsSExt) {
3727 ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
3728 InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
3729 if (It != PromotedInsts.end() && It->second.getInt() == ExtTy)
3730 return It->second.getPointer();
3731 return nullptr;
3732 }
3733
3734 /// Utility function to check whether or not a sign or zero extension
3735 /// of \p Inst with \p ConsideredExtType can be moved through \p Inst by
3736 /// either using the operands of \p Inst or promoting \p Inst.
3737 /// The type of the extension is defined by \p IsSExt.
3738 /// In other words, check if:
3739 /// ext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredExtType.
3740 /// #1 Promotion applies:
3741 /// ConsideredExtType Inst (ext opnd1 to ConsideredExtType, ...).
3742 /// #2 Operand reuses:
3743 /// ext opnd1 to ConsideredExtType.
3744 /// \p PromotedInsts maps the instructions to their type before promotion.
3745 static bool canGetThrough(const Instruction *Inst, Type *ConsideredExtType,
3746 const InstrToOrigTy &PromotedInsts, bool IsSExt);
3747
3748 /// Utility function to determine if \p OpIdx should be promoted when
3749 /// promoting \p Inst.
3750 static bool shouldExtOperand(const Instruction *Inst, int OpIdx) {
3751 return !(isa<SelectInst>(Inst) && OpIdx == 0);
3752 }
3753
3754 /// Utility function to promote the operand of \p Ext when this
3755 /// operand is a promotable trunc or sext or zext.
3756 /// \p PromotedInsts maps the instructions to their type before promotion.
3757 /// \p CreatedInstsCost[out] contains the cost of all instructions
3758 /// created to promote the operand of Ext.
3759 /// Newly added extensions are inserted in \p Exts.
3760 /// Newly added truncates are inserted in \p Truncs.
3761 /// Should never be called directly.
3762 /// \return The promoted value which is used instead of Ext.
3763 static Value *promoteOperandForTruncAndAnyExt(
3764 Instruction *Ext, TypePromotionTransaction &TPT,
3765 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3766 SmallVectorImpl<Instruction *> *Exts,
3767 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI);
3768
3769 /// Utility function to promote the operand of \p Ext when this
3770 /// operand is promotable and is not a supported trunc or sext.
3771 /// \p PromotedInsts maps the instructions to their type before promotion.
3772 /// \p CreatedInstsCost[out] contains the cost of all the instructions
3773 /// created to promote the operand of Ext.
3774 /// Newly added extensions are inserted in \p Exts.
3775 /// Newly added truncates are inserted in \p Truncs.
3776 /// Should never be called directly.
3777 /// \return The promoted value which is used instead of Ext.
3778 static Value *promoteOperandForOther(Instruction *Ext,
3779 TypePromotionTransaction &TPT,
3780 InstrToOrigTy &PromotedInsts,
3781 unsigned &CreatedInstsCost,
3782 SmallVectorImpl<Instruction *> *Exts,
3783 SmallVectorImpl<Instruction *> *Truncs,
3784 const TargetLowering &TLI, bool IsSExt);
3785
3786 /// \see promoteOperandForOther.
3787 static Value *signExtendOperandForOther(
3788 Instruction *Ext, TypePromotionTransaction &TPT,
3789 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3790 SmallVectorImpl<Instruction *> *Exts,
3791 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3792 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
3793 Exts, Truncs, TLI, true);
3794 }
3795
3796 /// \see promoteOperandForOther.
3797 static Value *zeroExtendOperandForOther(
3798 Instruction *Ext, TypePromotionTransaction &TPT,
3799 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3800 SmallVectorImpl<Instruction *> *Exts,
3801 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3802 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
3803 Exts, Truncs, TLI, false);
3804 }
3805
3806public:
3807 /// Type for the utility function that promotes the operand of Ext.
3808 using Action = Value *(*)(Instruction *Ext, TypePromotionTransaction &TPT,
3809 InstrToOrigTy &PromotedInsts,
3810 unsigned &CreatedInstsCost,
3811 SmallVectorImpl<Instruction *> *Exts,
3812 SmallVectorImpl<Instruction *> *Truncs,
3813 const TargetLowering &TLI);
3814
3815 /// Given a sign/zero extend instruction \p Ext, return the appropriate
3816 /// action to promote the operand of \p Ext instead of using Ext.
3817 /// \return NULL if no promotable action is possible with the current
3818 /// sign extension.
3819 /// \p InsertedInsts keeps track of all the instructions inserted by the
3820 /// other CodeGenPrepare optimizations. This information is important
3821 /// because we do not want to promote these instructions as CodeGenPrepare
3822 /// will reinsert them later. Thus creating an infinite loop: create/remove.
3823 /// \p PromotedInsts maps the instructions to their type before promotion.
3824 static Action getAction(Instruction *Ext, const SetOfInstrs &InsertedInsts,
3825 const TargetLowering &TLI,
3826 const InstrToOrigTy &PromotedInsts);
3827};
3828
3829} // end anonymous namespace
3830
3831bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
3832 Type *ConsideredExtType,
3833 const InstrToOrigTy &PromotedInsts,
3834 bool IsSExt) {
3835 // The promotion helper does not know how to deal with vector types yet.
3836 // To be able to fix that, we would need to fix the places where we
3837 // statically extend, e.g., constants and such.
3838 if (Inst->getType()->isVectorTy())
3839 return false;
3840
3841 // We can always get through zext.
3842 if (isa<ZExtInst>(Inst))
3843 return true;
3844
3845 // sext(sext) is ok too.
3846 if (IsSExt && isa<SExtInst>(Inst))
3847 return true;
3848
3849 // We can get through binary operator, if it is legal. In other words, the
3850 // binary operator must have a nuw or nsw flag.
3851 const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst);
3852 if (BinOp && isa<OverflowingBinaryOperator>(BinOp) &&
3853 ((!IsSExt && BinOp->hasNoUnsignedWrap()) ||
3854 (IsSExt && BinOp->hasNoSignedWrap())))
3855 return true;
3856
3857 // ext(and(opnd, cst)) --> and(ext(opnd), ext(cst))
3858 if ((Inst->getOpcode() == Instruction::And ||
3859 Inst->getOpcode() == Instruction::Or))
3860 return true;
3861
3862 // ext(xor(opnd, cst)) --> xor(ext(opnd), ext(cst))
3863 if (Inst->getOpcode() == Instruction::Xor) {
3864 const ConstantInt *Cst = dyn_cast<ConstantInt>(Inst->getOperand(1));
3865 // Make sure it is not a NOT.
3866 if (Cst && !Cst->getValue().isAllOnesValue())
3867 return true;
3868 }
3869
3870 // zext(shrl(opnd, cst)) --> shrl(zext(opnd), zext(cst))
3871 // It may change a poisoned value into a regular value, like
3872 // zext i32 (shrl i8 %val, 12) --> shrl i32 (zext i8 %val), 12
3873 // poisoned value regular value
3874 // It should be OK since undef covers valid value.
3875 if (Inst->getOpcode() == Instruction::LShr && !IsSExt)
3876 return true;
3877
3878 // and(ext(shl(opnd, cst)), cst) --> and(shl(ext(opnd), ext(cst)), cst)
3879 // It may change a poisoned value into a regular value, like
3880 // zext i32 (shl i8 %val, 12) --> shl i32 (zext i8 %val), 12
3881 // poisoned value regular value
3882 // It should be OK since undef covers valid value.
3883 if (Inst->getOpcode() == Instruction::Shl && Inst->hasOneUse()) {
3884 const auto *ExtInst = cast<const Instruction>(*Inst->user_begin());
3885 if (ExtInst->hasOneUse()) {
3886 const auto *AndInst = dyn_cast<const Instruction>(*ExtInst->user_begin());
3887 if (AndInst && AndInst->getOpcode() == Instruction::And) {
3888 const auto *Cst = dyn_cast<ConstantInt>(AndInst->getOperand(1));
3889 if (Cst &&
3890 Cst->getValue().isIntN(Inst->getType()->getIntegerBitWidth()))
3891 return true;
3892 }
3893 }
3894 }
3895
3896 // Check if we can do the following simplification.
3897 // ext(trunc(opnd)) --> ext(opnd)
3898 if (!isa<TruncInst>(Inst))
3899 return false;
3900
3901 Value *OpndVal = Inst->getOperand(0);
3902 // Check if we can use this operand in the extension.
3903 // If the type is larger than the result type of the extension, we cannot.
3904 if (!OpndVal->getType()->isIntegerTy() ||
3905 OpndVal->getType()->getIntegerBitWidth() >
3906 ConsideredExtType->getIntegerBitWidth())
3907 return false;
3908
3909 // If the operand of the truncate is not an instruction, we will not have
3910 // any information on the dropped bits.
3911 // (Actually we could for constant but it is not worth the extra logic).
3912 Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
3913 if (!Opnd)
3914 return false;
3915
3916 // Check if the source of the type is narrow enough.
3917 // I.e., check that trunc just drops extended bits of the same kind of
3918 // the extension.
3919 // #1 get the type of the operand and check the kind of the extended bits.
3920 const Type *OpndType = getOrigType(PromotedInsts, Opnd, IsSExt);
3921 if (OpndType)
3922 ;
3923 else if ((IsSExt && isa<SExtInst>(Opnd)) || (!IsSExt && isa<ZExtInst>(Opnd)))
3924 OpndType = Opnd->getOperand(0)->getType();
3925 else
3926 return false;
3927
3928 // #2 check that the truncate just drops extended bits.
3929 return Inst->getType()->getIntegerBitWidth() >=
3930 OpndType->getIntegerBitWidth();
3931}
3932
3933TypePromotionHelper::Action TypePromotionHelper::getAction(
3934 Instruction *Ext, const SetOfInstrs &InsertedInsts,
3935 const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
3936 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3937, __PRETTY_FUNCTION__))
3937 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 3937, __PRETTY_FUNCTION__))
;
3938 Instruction *ExtOpnd = dyn_cast<Instruction>(Ext->getOperand(0));
3939 Type *ExtTy = Ext->getType();
3940 bool IsSExt = isa<SExtInst>(Ext);
3941 // If the operand of the extension is not an instruction, we cannot
3942 // get through.
3943 // If it, check we can get through.
3944 if (!ExtOpnd || !canGetThrough(ExtOpnd, ExtTy, PromotedInsts, IsSExt))
3945 return nullptr;
3946
3947 // Do not promote if the operand has been added by codegenprepare.
3948 // Otherwise, it means we are undoing an optimization that is likely to be
3949 // redone, thus causing potential infinite loop.
3950 if (isa<TruncInst>(ExtOpnd) && InsertedInsts.count(ExtOpnd))
3951 return nullptr;
3952
3953 // SExt or Trunc instructions.
3954 // Return the related handler.
3955 if (isa<SExtInst>(ExtOpnd) || isa<TruncInst>(ExtOpnd) ||
3956 isa<ZExtInst>(ExtOpnd))
3957 return promoteOperandForTruncAndAnyExt;
3958
3959 // Regular instruction.
3960 // Abort early if we will have to insert non-free instructions.
3961 if (!ExtOpnd->hasOneUse() && !TLI.isTruncateFree(ExtTy, ExtOpnd->getType()))
3962 return nullptr;
3963 return IsSExt ? signExtendOperandForOther : zeroExtendOperandForOther;
3964}
3965
3966Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
3967 Instruction *SExt, TypePromotionTransaction &TPT,
3968 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3969 SmallVectorImpl<Instruction *> *Exts,
3970 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3971 // By construction, the operand of SExt is an instruction. Otherwise we cannot
3972 // get through it and this method should not be called.
3973 Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
3974 Value *ExtVal = SExt;
3975 bool HasMergedNonFreeExt = false;
3976 if (isa<ZExtInst>(SExtOpnd)) {
3977 // Replace s|zext(zext(opnd))
3978 // => zext(opnd).
3979 HasMergedNonFreeExt = !TLI.isExtFree(SExtOpnd);
3980 Value *ZExt =
3981 TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
3982 TPT.replaceAllUsesWith(SExt, ZExt);
3983 TPT.eraseInstruction(SExt);
3984 ExtVal = ZExt;
3985 } else {
3986 // Replace z|sext(trunc(opnd)) or sext(sext(opnd))
3987 // => z|sext(opnd).
3988 TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
3989 }
3990 CreatedInstsCost = 0;
3991
3992 // Remove dead code.
3993 if (SExtOpnd->use_empty())
3994 TPT.eraseInstruction(SExtOpnd);
3995
3996 // Check if the extension is still needed.
3997 Instruction *ExtInst = dyn_cast<Instruction>(ExtVal);
3998 if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) {
3999 if (ExtInst) {
4000 if (Exts)
4001 Exts->push_back(ExtInst);
4002 CreatedInstsCost = !TLI.isExtFree(ExtInst) && !HasMergedNonFreeExt;
4003 }
4004 return ExtVal;
4005 }
4006
4007 // At this point we have: ext ty opnd to ty.
4008 // Reassign the uses of ExtInst to the opnd and remove ExtInst.
4009 Value *NextVal = ExtInst->getOperand(0);
4010 TPT.eraseInstruction(ExtInst, NextVal);
4011 return NextVal;
4012}
4013
4014Value *TypePromotionHelper::promoteOperandForOther(
4015 Instruction *Ext, TypePromotionTransaction &TPT,
4016 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4017 SmallVectorImpl<Instruction *> *Exts,
4018 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI,
4019 bool IsSExt) {
4020 // By construction, the operand of Ext is an instruction. Otherwise we cannot
4021 // get through it and this method should not be called.
4022 Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0));
4023 CreatedInstsCost = 0;
4024 if (!ExtOpnd->hasOneUse()) {
4025 // ExtOpnd will be promoted.
4026 // All its uses, but Ext, will need to use a truncated value of the
4027 // promoted version.
4028 // Create the truncate now.
4029 Value *Trunc = TPT.createTrunc(Ext, ExtOpnd->getType());
4030 if (Instruction *ITrunc = dyn_cast<Instruction>(Trunc)) {
4031 // Insert it just after the definition.
4032 ITrunc->moveAfter(ExtOpnd);
4033 if (Truncs)
4034 Truncs->push_back(ITrunc);
4035 }
4036
4037 TPT.replaceAllUsesWith(ExtOpnd, Trunc);
4038 // Restore the operand of Ext (which has been replaced by the previous call
4039 // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
4040 TPT.setOperand(Ext, 0, ExtOpnd);
4041 }
4042
4043 // Get through the Instruction:
4044 // 1. Update its type.
4045 // 2. Replace the uses of Ext by Inst.
4046 // 3. Extend each operand that needs to be extended.
4047
4048 // Remember the original type of the instruction before promotion.
4049 // This is useful to know that the high bits are sign extended bits.
4050 addPromotedInst(PromotedInsts, ExtOpnd, IsSExt);
4051 // Step #1.
4052 TPT.mutateType(ExtOpnd, Ext->getType());
4053 // Step #2.
4054 TPT.replaceAllUsesWith(Ext, ExtOpnd);
4055 // Step #3.
4056 Instruction *ExtForOpnd = Ext;
4057
4058 LLVM_DEBUG(dbgs() << "Propagate Ext to operands\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Propagate Ext to operands\n"
; } } while (false)
;
4059 for (int OpIdx = 0, EndOpIdx = ExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
4060 ++OpIdx) {
4061 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
)
;
4062 if (ExtOpnd->getOperand(OpIdx)->getType() == Ext->getType() ||
4063 !shouldExtOperand(ExtOpnd, OpIdx)) {
4064 LLVM_DEBUG(dbgs() << "No need to propagate\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "No need to propagate\n"
; } } while (false)
;
4065 continue;
4066 }
4067 // Check if we can statically extend the operand.
4068 Value *Opnd = ExtOpnd->getOperand(OpIdx);
4069 if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
4070 LLVM_DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
} while (false)
;
4071 unsigned BitWidth = Ext->getType()->getIntegerBitWidth();
4072 APInt CstVal = IsSExt ? Cst->getValue().sext(BitWidth)
4073 : Cst->getValue().zext(BitWidth);
4074 TPT.setOperand(ExtOpnd, OpIdx, ConstantInt::get(Ext->getType(), CstVal));
4075 continue;
4076 }
4077 // UndefValue are typed, so we have to statically sign extend them.
4078 if (isa<UndefValue>(Opnd)) {
4079 LLVM_DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
} while (false)
;
4080 TPT.setOperand(ExtOpnd, OpIdx, UndefValue::get(Ext->getType()));
4081 continue;
4082 }
4083
4084 // Otherwise we have to explicitly sign extend the operand.
4085 // Check if Ext was reused to extend an operand.
4086 if (!ExtForOpnd) {
4087 // If yes, create a new one.
4088 LLVM_DEBUG(dbgs() << "More operands to ext\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "More operands to ext\n"
; } } while (false)
;
4089 Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
4090 : TPT.createZExt(Ext, Opnd, Ext->getType());
4091 if (!isa<Instruction>(ValForExtOpnd)) {
4092 TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd);
4093 continue;
4094 }
4095 ExtForOpnd = cast<Instruction>(ValForExtOpnd);
4096 }
4097 if (Exts)
4098 Exts->push_back(ExtForOpnd);
4099 TPT.setOperand(ExtForOpnd, 0, Opnd);
4100
4101 // Move the sign extension before the insertion point.
4102 TPT.moveBefore(ExtForOpnd, ExtOpnd);
4103 TPT.setOperand(ExtOpnd, OpIdx, ExtForOpnd);
4104 CreatedInstsCost += !TLI.isExtFree(ExtForOpnd);
4105 // If more sext are required, new instructions will have to be created.
4106 ExtForOpnd = nullptr;
4107 }
4108 if (ExtForOpnd == Ext) {
4109 LLVM_DEBUG(dbgs() << "Extension is useless now\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Extension is useless now\n"
; } } while (false)
;
4110 TPT.eraseInstruction(Ext);
4111 }
4112 return ExtOpnd;
4113}
4114
4115/// Check whether or not promoting an instruction to a wider type is profitable.
4116/// \p NewCost gives the cost of extension instructions created by the
4117/// promotion.
4118/// \p OldCost gives the cost of extension instructions before the promotion
4119/// plus the number of instructions that have been
4120/// matched in the addressing mode the promotion.
4121/// \p PromotedOperand is the value that has been promoted.
4122/// \return True if the promotion is profitable, false otherwise.
4123bool AddressingModeMatcher::isPromotionProfitable(
4124 unsigned NewCost, unsigned OldCost, Value *PromotedOperand) const {
4125 LLVM_DEBUG(dbgs() << "OldCost: " << OldCost << "\tNewCost: " << NewCostdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "OldCost: " << OldCost
<< "\tNewCost: " << NewCost << '\n'; } } while
(false)
4126 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "OldCost: " << OldCost
<< "\tNewCost: " << NewCost << '\n'; } } while
(false)
;
4127 // The cost of the new extensions is greater than the cost of the
4128 // old extension plus what we folded.
4129 // This is not profitable.
4130 if (NewCost > OldCost)
4131 return false;
4132 if (NewCost < OldCost)
4133 return true;
4134 // The promotion is neutral but it may help folding the sign extension in
4135 // loads for instance.
4136 // Check that we did not create an illegal instruction.
4137 return isPromotedInstructionLegal(TLI, DL, PromotedOperand);
4138}
4139
4140/// Given an instruction or constant expr, see if we can fold the operation
4141/// into the addressing mode. If so, update the addressing mode and return
4142/// true, otherwise return false without modifying AddrMode.
4143/// If \p MovedAway is not NULL, it contains the information of whether or
4144/// not AddrInst has to be folded into the addressing mode on success.
4145/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
4146/// because it has been moved away.
4147/// Thus AddrInst must not be added in the matched instructions.
4148/// This state can happen when AddrInst is a sext, since it may be moved away.
4149/// Therefore, AddrInst may not be valid when MovedAway is true and it must
4150/// not be referenced anymore.
4151bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
4152 unsigned Depth,
4153 bool *MovedAway) {
4154 // Avoid exponential behavior on extremely deep expression trees.
4155 if (Depth >= 5) return false;
4156
4157 // By default, all matched instructions stay in place.
4158 if (MovedAway)
4159 *MovedAway = false;
4160
4161 switch (Opcode) {
4162 case Instruction::PtrToInt:
4163 // PtrToInt is always a noop, as we know that the int type is pointer sized.
4164 return matchAddr(AddrInst->getOperand(0), Depth);
4165 case Instruction::IntToPtr: {
4166 auto AS = AddrInst->getType()->getPointerAddressSpace();
4167 auto PtrTy = MVT::getIntegerVT(DL.getPointerSizeInBits(AS));
4168 // This inttoptr is a no-op if the integer type is pointer sized.
4169 if (TLI.getValueType(DL, AddrInst->getOperand(0)->getType()) == PtrTy)
4170 return matchAddr(AddrInst->getOperand(0), Depth);
4171 return false;
4172 }
4173 case Instruction::BitCast:
4174 // BitCast is always a noop, and we can handle it as long as it is
4175 // int->int or pointer->pointer (we don't want int<->fp or something).
4176 if (AddrInst->getOperand(0)->getType()->isIntOrPtrTy() &&
4177 // Don't touch identity bitcasts. These were probably put here by LSR,
4178 // and we don't want to mess around with them. Assume it knows what it
4179 // is doing.
4180 AddrInst->getOperand(0)->getType() != AddrInst->getType())
4181 return matchAddr(AddrInst->getOperand(0), Depth);
4182 return false;
4183 case Instruction::AddrSpaceCast: {
4184 unsigned SrcAS
4185 = AddrInst->getOperand(0)->getType()->getPointerAddressSpace();
4186 unsigned DestAS = AddrInst->getType()->getPointerAddressSpace();
4187 if (TLI.isNoopAddrSpaceCast(SrcAS, DestAS))
4188 return matchAddr(AddrInst->getOperand(0), Depth);
4189 return false;
4190 }
4191 case Instruction::Add: {
4192 // Check to see if we can merge in the RHS then the LHS. If so, we win.
4193 ExtAddrMode BackupAddrMode = AddrMode;
4194 unsigned OldSize = AddrModeInsts.size();
4195 // Start a transaction at this point.
4196 // The LHS may match but not the RHS.
4197 // Therefore, we need a higher level restoration point to undo partially
4198 // matched operation.
4199 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4200 TPT.getRestorationPoint();
4201
4202 AddrMode.InBounds = false;
4203 if (matchAddr(AddrInst->getOperand(1), Depth+1) &&
4204 matchAddr(AddrInst->getOperand(0), Depth+1))
4205 return true;
4206
4207 // Restore the old addr mode info.
4208 AddrMode = BackupAddrMode;
4209 AddrModeInsts.resize(OldSize);
4210 TPT.rollback(LastKnownGood);
4211
4212 // Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
4213 if (matchAddr(AddrInst->getOperand(0), Depth+1) &&
4214 matchAddr(AddrInst->getOperand(1), Depth+1))
4215 return true;
4216
4217 // Otherwise we definitely can't merge the ADD in.
4218 AddrMode = BackupAddrMode;
4219 AddrModeInsts.resize(OldSize);
4220 TPT.rollback(LastKnownGood);
4221 break;
4222 }
4223 //case Instruction::Or:
4224 // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
4225 //break;
4226 case Instruction::Mul:
4227 case Instruction::Shl: {
4228 // Can only handle X*C and X << C.
4229 AddrMode.InBounds = false;
4230 ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
4231 if (!RHS || RHS->getBitWidth() > 64)
4232 return false;
4233 int64_t Scale = RHS->getSExtValue();
4234 if (Opcode == Instruction::Shl)
4235 Scale = 1LL << Scale;
4236
4237 return matchScaledValue(AddrInst->getOperand(0), Scale, Depth);
4238 }
4239 case Instruction::GetElementPtr: {
4240 // Scan the GEP. We check it if it contains constant offsets and at most
4241 // one variable offset.
4242 int VariableOperand = -1;
4243 unsigned VariableScale = 0;
4244
4245 int64_t ConstantOffset = 0;
4246 gep_type_iterator GTI = gep_type_begin(AddrInst);
4247 for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
4248 if (StructType *STy = GTI.getStructTypeOrNull()) {
4249 const StructLayout *SL = DL.getStructLayout(STy);
4250 unsigned Idx =
4251 cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
4252 ConstantOffset += SL->getElementOffset(Idx);
4253 } else {
4254 uint64_t TypeSize = DL.getTypeAllocSize(GTI.getIndexedType());
4255 if (ConstantInt *CI = dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
4256 const APInt &CVal = CI->getValue();
4257 if (CVal.getMinSignedBits() <= 64) {
4258 ConstantOffset += CVal.getSExtValue() * TypeSize;
4259 continue;
4260 }
4261 }
4262 if (TypeSize) { // Scales of zero don't do anything.
4263 // We only allow one variable index at the moment.
4264 if (VariableOperand != -1)
4265 return false;
4266
4267 // Remember the variable index.
4268 VariableOperand = i;
4269 VariableScale = TypeSize;
4270 }
4271 }
4272 }
4273
4274 // A common case is for the GEP to only do a constant offset. In this case,
4275 // just add it to the disp field and check validity.
4276 if (VariableOperand == -1) {
4277 AddrMode.BaseOffs += ConstantOffset;
4278 if (ConstantOffset == 0 ||
4279 TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) {
4280 // Check to see if we can fold the base pointer in too.
4281 if (matchAddr(AddrInst->getOperand(0), Depth+1)) {
4282 if (!cast<GEPOperator>(AddrInst)->isInBounds())
4283 AddrMode.InBounds = false;
4284 return true;
4285 }
4286 } else if (EnableGEPOffsetSplit && isa<GetElementPtrInst>(AddrInst) &&
4287 TLI.shouldConsiderGEPOffsetSplit() && Depth == 0 &&
4288 ConstantOffset > 0) {
4289 // Record GEPs with non-zero offsets as candidates for splitting in the
4290 // event that the offset cannot fit into the r+i addressing mode.
4291 // Simple and common case that only one GEP is used in calculating the
4292 // address for the memory access.
4293 Value *Base = AddrInst->getOperand(0);
4294 auto *BaseI = dyn_cast<Instruction>(Base);
4295 auto *GEP = cast<GetElementPtrInst>(AddrInst);
4296 if (isa<Argument>(Base) || isa<GlobalValue>(Base) ||
4297 (BaseI && !isa<CastInst>(BaseI) &&
4298 !isa<GetElementPtrInst>(BaseI))) {
4299 // Make sure the parent block allows inserting non-PHI instructions
4300 // before the terminator.
4301 BasicBlock *Parent =
4302 BaseI ? BaseI->getParent() : &GEP->getFunction()->getEntryBlock();
4303 if (!Parent->getTerminator()->isEHPad())
4304 LargeOffsetGEP = std::make_pair(GEP, ConstantOffset);
4305 }
4306 }
4307 AddrMode.BaseOffs -= ConstantOffset;
4308 return false;
4309 }
4310
4311 // Save the valid addressing mode in case we can't match.
4312 ExtAddrMode BackupAddrMode = AddrMode;
4313 unsigned OldSize = AddrModeInsts.size();
4314
4315 // See if the scale and offset amount is valid for this target.
4316 AddrMode.BaseOffs += ConstantOffset;
4317 if (!cast<GEPOperator>(AddrInst)->isInBounds())
4318 AddrMode.InBounds = false;
4319
4320 // Match the base operand of the GEP.
4321 if (!matchAddr(AddrInst->getOperand(0), Depth+1)) {
4322 // If it couldn't be matched, just stuff the value in a register.
4323 if (AddrMode.HasBaseReg) {
4324 AddrMode = BackupAddrMode;
4325 AddrModeInsts.resize(OldSize);
4326 return false;
4327 }
4328 AddrMode.HasBaseReg = true;
4329 AddrMode.BaseReg = AddrInst->getOperand(0);
4330 }
4331
4332 // Match the remaining variable portion of the GEP.
4333 if (!matchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
4334 Depth)) {
4335 // If it couldn't be matched, try stuffing the base into a register
4336 // instead of matching it, and retrying the match of the scale.
4337 AddrMode = BackupAddrMode;
4338 AddrModeInsts.resize(OldSize);
4339 if (AddrMode.HasBaseReg)
4340 return false;
4341 AddrMode.HasBaseReg = true;
4342 AddrMode.BaseReg = AddrInst->getOperand(0);
4343 AddrMode.BaseOffs += ConstantOffset;
4344 if (!matchScaledValue(AddrInst->getOperand(VariableOperand),
4345 VariableScale, Depth)) {
4346 // If even that didn't work, bail.
4347 AddrMode = BackupAddrMode;
4348 AddrModeInsts.resize(OldSize);
4349 return false;
4350 }
4351 }
4352
4353 return true;
4354 }
4355 case Instruction::SExt:
4356 case Instruction::ZExt: {
4357 Instruction *Ext = dyn_cast<Instruction>(AddrInst);
4358 if (!Ext)
4359 return false;
4360
4361 // Try to move this ext out of the way of the addressing mode.
4362 // Ask for a method for doing so.
4363 TypePromotionHelper::Action TPH =
4364 TypePromotionHelper::getAction(Ext, InsertedInsts, TLI, PromotedInsts);
4365 if (!TPH)
4366 return false;
4367
4368 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4369 TPT.getRestorationPoint();
4370 unsigned CreatedInstsCost = 0;
4371 unsigned ExtCost = !TLI.isExtFree(Ext);
4372 Value *PromotedOperand =
4373 TPH(Ext, TPT, PromotedInsts, CreatedInstsCost, nullptr, nullptr, TLI);
4374 // SExt has been moved away.
4375 // Thus either it will be rematched later in the recursive calls or it is
4376 // gone. Anyway, we must not fold it into the addressing mode at this point.
4377 // E.g.,
4378 // op = add opnd, 1
4379 // idx = ext op
4380 // addr = gep base, idx
4381 // is now:
4382 // promotedOpnd = ext opnd <- no match here
4383 // op = promoted_add promotedOpnd, 1 <- match (later in recursive calls)
4384 // addr = gep base, op <- match
4385 if (MovedAway)
4386 *MovedAway = true;
4387
4388 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4389, __PRETTY_FUNCTION__))
4389 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4389, __PRETTY_FUNCTION__))
;
4390
4391 ExtAddrMode BackupAddrMode = AddrMode;
4392 unsigned OldSize = AddrModeInsts.size();
4393
4394 if (!matchAddr(PromotedOperand, Depth) ||
4395 // The total of the new cost is equal to the cost of the created
4396 // instructions.
4397 // The total of the old cost is equal to the cost of the extension plus
4398 // what we have saved in the addressing mode.
4399 !isPromotionProfitable(CreatedInstsCost,
4400 ExtCost + (AddrModeInsts.size() - OldSize),
4401 PromotedOperand)) {
4402 AddrMode = BackupAddrMode;
4403 AddrModeInsts.resize(OldSize);
4404 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)
;
4405 TPT.rollback(LastKnownGood);
4406 return false;
4407 }
4408 return true;
4409 }
4410 }
4411 return false;
4412}
4413
4414/// If we can, try to add the value of 'Addr' into the current addressing mode.
4415/// If Addr can't be added to AddrMode this returns false and leaves AddrMode
4416/// unmodified. This assumes that Addr is either a pointer type or intptr_t
4417/// for the target.
4418///
4419bool AddressingModeMatcher::matchAddr(Value *Addr, unsigned Depth) {
4420 // Start a transaction at this point that we will rollback if the matching
4421 // fails.
4422 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4423 TPT.getRestorationPoint();
4424 if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
4425 // Fold in immediates if legal for the target.
4426 AddrMode.BaseOffs += CI->getSExtValue();
4427 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4428 return true;
4429 AddrMode.BaseOffs -= CI->getSExtValue();
4430 } else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
4431 // If this is a global variable, try to fold it into the addressing mode.
4432 if (!AddrMode.BaseGV) {
4433 AddrMode.BaseGV = GV;
4434 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4435 return true;
4436 AddrMode.BaseGV = nullptr;
4437 }
4438 } else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
4439 ExtAddrMode BackupAddrMode = AddrMode;
4440 unsigned OldSize = AddrModeInsts.size();
4441
4442 // Check to see if it is possible to fold this operation.
4443 bool MovedAway = false;
4444 if (matchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
4445 // This instruction may have been moved away. If so, there is nothing
4446 // to check here.
4447 if (MovedAway)
4448 return true;
4449 // Okay, it's possible to fold this. Check to see if it is actually
4450 // *profitable* to do so. We use a simple cost model to avoid increasing
4451 // register pressure too much.
4452 if (I->hasOneUse() ||
4453 isProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
4454 AddrModeInsts.push_back(I);
4455 return true;
4456 }
4457
4458 // It isn't profitable to do this, roll back.
4459 //cerr << "NOT FOLDING: " << *I;
4460 AddrMode = BackupAddrMode;
4461 AddrModeInsts.resize(OldSize);
4462 TPT.rollback(LastKnownGood);
4463 }
4464 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
4465 if (matchOperationAddr(CE, CE->getOpcode(), Depth))
4466 return true;
4467 TPT.rollback(LastKnownGood);
4468 } else if (isa<ConstantPointerNull>(Addr)) {
4469 // Null pointer gets folded without affecting the addressing mode.
4470 return true;
4471 }
4472
4473 // Worse case, the target should support [reg] addressing modes. :)
4474 if (!AddrMode.HasBaseReg) {
4475 AddrMode.HasBaseReg = true;
4476 AddrMode.BaseReg = Addr;
4477 // Still check for legality in case the target supports [imm] but not [i+r].
4478 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4479 return true;
4480 AddrMode.HasBaseReg = false;
4481 AddrMode.BaseReg = nullptr;
4482 }
4483
4484 // If the base register is already taken, see if we can do [r+r].
4485 if (AddrMode.Scale == 0) {
4486 AddrMode.Scale = 1;
4487 AddrMode.ScaledReg = Addr;
4488 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4489 return true;
4490 AddrMode.Scale = 0;
4491 AddrMode.ScaledReg = nullptr;
4492 }
4493 // Couldn't match.
4494 TPT.rollback(LastKnownGood);
4495 return false;
4496}
4497
4498/// Check to see if all uses of OpVal by the specified inline asm call are due
4499/// to memory operands. If so, return true, otherwise return false.
4500static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
4501 const TargetLowering &TLI,
4502 const TargetRegisterInfo &TRI) {
4503 const Function *F = CI->getFunction();
4504 TargetLowering::AsmOperandInfoVector TargetConstraints =
4505 TLI.ParseConstraints(F->getParent()->getDataLayout(), &TRI,
4506 ImmutableCallSite(CI));
4507
4508 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
4509 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
4510
4511 // Compute the constraint code and ConstraintType to use.
4512 TLI.ComputeConstraintToUse(OpInfo, SDValue());
4513
4514 // If this asm operand is our Value*, and if it isn't an indirect memory
4515 // operand, we can't fold it!
4516 if (OpInfo.CallOperandVal == OpVal &&
4517 (OpInfo.ConstraintType != TargetLowering::C_Memory ||
4518 !OpInfo.isIndirect))
4519 return false;
4520 }
4521
4522 return true;
4523}
4524
4525// Max number of memory uses to look at before aborting the search to conserve
4526// compile time.
4527static constexpr int MaxMemoryUsesToScan = 20;
4528
4529/// Recursively walk all the uses of I until we find a memory use.
4530/// If we find an obviously non-foldable instruction, return true.
4531/// Add the ultimately found memory instructions to MemoryUses.
4532static bool FindAllMemoryUses(
4533 Instruction *I,
4534 SmallVectorImpl<std::pair<Instruction *, unsigned>> &MemoryUses,
4535 SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetLowering &TLI,
4536 const TargetRegisterInfo &TRI, bool OptSize, ProfileSummaryInfo *PSI,
4537 BlockFrequencyInfo *BFI, int SeenInsts = 0) {
4538 // If we already considered this instruction, we're done.
4539 if (!ConsideredInsts.insert(I).second)
4540 return false;
4541
4542 // If this is an obviously unfoldable instruction, bail out.
4543 if (!MightBeFoldableInst(I))
4544 return true;
4545
4546 // Loop over all the uses, recursively processing them.
4547 for (Use &U : I->uses()) {
4548 // Conservatively return true if we're seeing a large number or a deep chain
4549 // of users. This avoids excessive compilation times in pathological cases.
4550 if (SeenInsts++ >= MaxMemoryUsesToScan)
4551 return true;
4552
4553 Instruction *UserI = cast<Instruction>(U.getUser());
4554 if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) {
4555 MemoryUses.push_back(std::make_pair(LI, U.getOperandNo()));
4556 continue;
4557 }
4558
4559 if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) {
4560 unsigned opNo = U.getOperandNo();
4561 if (opNo != StoreInst::getPointerOperandIndex())
4562 return true; // Storing addr, not into addr.
4563 MemoryUses.push_back(std::make_pair(SI, opNo));
4564 continue;
4565 }
4566
4567 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(UserI)) {
4568 unsigned opNo = U.getOperandNo();
4569 if (opNo != AtomicRMWInst::getPointerOperandIndex())
4570 return true; // Storing addr, not into addr.
4571 MemoryUses.push_back(std::make_pair(RMW, opNo));
4572 continue;
4573 }
4574
4575 if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(UserI)) {
4576 unsigned opNo = U.getOperandNo();
4577 if (opNo != AtomicCmpXchgInst::getPointerOperandIndex())
4578 return true; // Storing addr, not into addr.
4579 MemoryUses.push_back(std::make_pair(CmpX, opNo));
4580 continue;
4581 }
4582
4583 if (CallInst *CI = dyn_cast<CallInst>(UserI)) {
4584 // If this is a cold call, we can sink the addressing calculation into
4585 // the cold path. See optimizeCallInst
4586 bool OptForSize = OptSize ||
4587 llvm::shouldOptimizeForSize(CI->getParent(), PSI, BFI);
4588 if (!OptForSize && CI->hasFnAttr(Attribute::Cold))
4589 continue;
4590
4591 InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue());
4592 if (!IA) return true;
4593
4594 // If this is a memory operand, we're cool, otherwise bail out.
4595 if (!IsOperandAMemoryOperand(CI, IA, I, TLI, TRI))
4596 return true;
4597 continue;
4598 }
4599
4600 if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
4601 PSI, BFI, SeenInsts))
4602 return true;
4603 }
4604
4605 return false;
4606}
4607
4608/// Return true if Val is already known to be live at the use site that we're
4609/// folding it into. If so, there is no cost to include it in the addressing
4610/// mode. KnownLive1 and KnownLive2 are two values that we know are live at the
4611/// instruction already.
4612bool AddressingModeMatcher::valueAlreadyLiveAtInst(Value *Val,Value *KnownLive1,
4613 Value *KnownLive2) {
4614 // If Val is either of the known-live values, we know it is live!
4615 if (Val == nullptr || Val == KnownLive1 || Val == KnownLive2)
4616 return true;
4617
4618 // All values other than instructions and arguments (e.g. constants) are live.
4619 if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true;
4620
4621 // If Val is a constant sized alloca in the entry block, it is live, this is
4622 // true because it is just a reference to the stack/frame pointer, which is
4623 // live for the whole function.
4624 if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
4625 if (AI->isStaticAlloca())
4626 return true;
4627
4628 // Check to see if this value is already used in the memory instruction's
4629 // block. If so, it's already live into the block at the very least, so we
4630 // can reasonably fold it.
4631 return Val->isUsedInBasicBlock(MemoryInst->getParent());
4632}
4633
4634/// It is possible for the addressing mode of the machine to fold the specified
4635/// instruction into a load or store that ultimately uses it.
4636/// However, the specified instruction has multiple uses.
4637/// Given this, it may actually increase register pressure to fold it
4638/// into the load. For example, consider this code:
4639///
4640/// X = ...
4641/// Y = X+1
4642/// use(Y) -> nonload/store
4643/// Z = Y+1
4644/// load Z
4645///
4646/// In this case, Y has multiple uses, and can be folded into the load of Z
4647/// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to
4648/// be live at the use(Y) line. If we don't fold Y into load Z, we use one
4649/// fewer register. Since Y can't be folded into "use(Y)" we don't increase the
4650/// number of computations either.
4651///
4652/// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If
4653/// X was live across 'load Z' for other reasons, we actually *would* want to
4654/// fold the addressing mode in the Z case. This would make Y die earlier.
4655bool AddressingModeMatcher::
4656isProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore,
4657 ExtAddrMode &AMAfter) {
4658 if (IgnoreProfitability) return true;
4659
4660 // AMBefore is the addressing mode before this instruction was folded into it,
4661 // and AMAfter is the addressing mode after the instruction was folded. Get
4662 // the set of registers referenced by AMAfter and subtract out those
4663 // referenced by AMBefore: this is the set of values which folding in this
4664 // address extends the lifetime of.
4665 //
4666 // Note that there are only two potential values being referenced here,
4667 // BaseReg and ScaleReg (global addresses are always available, as are any
4668 // folded immediates).
4669 Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;
4670
4671 // If the BaseReg or ScaledReg was referenced by the previous addrmode, their
4672 // lifetime wasn't extended by adding this instruction.
4673 if (valueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
4674 BaseReg = nullptr;
4675 if (valueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
4676 ScaledReg = nullptr;
4677
4678 // If folding this instruction (and it's subexprs) didn't extend any live
4679 // ranges, we're ok with it.
4680 if (!BaseReg && !ScaledReg)
4681 return true;
4682
4683 // If all uses of this instruction can have the address mode sunk into them,
4684 // we can remove the addressing mode and effectively trade one live register
4685 // for another (at worst.) In this context, folding an addressing mode into
4686 // the use is just a particularly nice way of sinking it.
4687 SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
4688 SmallPtrSet<Instruction*, 16> ConsideredInsts;
4689 if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
4690 PSI, BFI))
4691 return false; // Has a non-memory, non-foldable use!
4692
4693 // Now that we know that all uses of this instruction are part of a chain of
4694 // computation involving only operations that could theoretically be folded
4695 // into a memory use, loop over each of these memory operation uses and see
4696 // if they could *actually* fold the instruction. The assumption is that
4697 // addressing modes are cheap and that duplicating the computation involved
4698 // many times is worthwhile, even on a fastpath. For sinking candidates
4699 // (i.e. cold call sites), this serves as a way to prevent excessive code
4700 // growth since most architectures have some reasonable small and fast way to
4701 // compute an effective address. (i.e LEA on x86)
4702 SmallVector<Instruction*, 32> MatchedAddrModeInsts;
4703 for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) {
4704 Instruction *User = MemoryUses[i].first;
4705 unsigned OpNo = MemoryUses[i].second;
4706
4707 // Get the access type of this use. If the use isn't a pointer, we don't
4708 // know what it accesses.
4709 Value *Address = User->getOperand(OpNo);
4710 PointerType *AddrTy = dyn_cast<PointerType>(Address->getType());
4711 if (!AddrTy)
4712 return false;
4713 Type *AddressAccessTy = AddrTy->getElementType();
4714 unsigned AS = AddrTy->getAddressSpace();
4715
4716 // Do a match against the root of this address, ignoring profitability. This
4717 // will tell us if the addressing mode for the memory operation will
4718 // *actually* cover the shared instruction.
4719 ExtAddrMode Result;
4720 std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
4721 0);
4722 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4723 TPT.getRestorationPoint();
4724 AddressingModeMatcher Matcher(
4725 MatchedAddrModeInsts, TLI, TRI, AddressAccessTy, AS, MemoryInst, Result,
4726 InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI, BFI);
4727 Matcher.IgnoreProfitability = true;
4728 bool Success = Matcher.matchAddr(Address, 0);
4729 (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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4729, __PRETTY_FUNCTION__))
;
4730
4731 // The match was to check the profitability, the changes made are not
4732 // part of the original matcher. Therefore, they should be dropped
4733 // otherwise the original matcher will not present the right state.
4734 TPT.rollback(LastKnownGood);
4735
4736 // If the match didn't cover I, then it won't be shared by it.
4737 if (!is_contained(MatchedAddrModeInsts, I))
4738 return false;
4739
4740 MatchedAddrModeInsts.clear();
4741 }
4742
4743 return true;
4744}
4745
4746/// Return true if the specified values are defined in a
4747/// different basic block than BB.
4748static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
4749 if (Instruction *I = dyn_cast<Instruction>(V))
4750 return I->getParent() != BB;
4751 return false;
4752}
4753
4754/// Sink addressing mode computation immediate before MemoryInst if doing so
4755/// can be done without increasing register pressure. The need for the
4756/// register pressure constraint means this can end up being an all or nothing
4757/// decision for all uses of the same addressing computation.
4758///
4759/// Load and Store Instructions often have addressing modes that can do
4760/// significant amounts of computation. As such, instruction selection will try
4761/// to get the load or store to do as much computation as possible for the
4762/// program. The problem is that isel can only see within a single block. As
4763/// such, we sink as much legal addressing mode work into the block as possible.
4764///
4765/// This method is used to optimize both load/store and inline asms with memory
4766/// operands. It's also used to sink addressing computations feeding into cold
4767/// call sites into their (cold) basic block.
4768///
4769/// The motivation for handling sinking into cold blocks is that doing so can
4770/// both enable other address mode sinking (by satisfying the register pressure
4771/// constraint above), and reduce register pressure globally (by removing the
4772/// addressing mode computation from the fast path entirely.).
4773bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
4774 Type *AccessTy, unsigned AddrSpace) {
4775 Value *Repl = Addr;
4776
4777 // Try to collapse single-value PHI nodes. This is necessary to undo
4778 // unprofitable PRE transformations.
4779 SmallVector<Value*, 8> worklist;
4780 SmallPtrSet<Value*, 16> Visited;
4781 worklist.push_back(Addr);
4782
4783 // Use a worklist to iteratively look through PHI and select nodes, and
4784 // ensure that the addressing mode obtained from the non-PHI/select roots of
4785 // the graph are compatible.
4786 bool PhiOrSelectSeen = false;
4787 SmallVector<Instruction*, 16> AddrModeInsts;
4788 const SimplifyQuery SQ(*DL, TLInfo);
4789 AddressingModeCombiner AddrModes(SQ, Addr);
4790 TypePromotionTransaction TPT(RemovedInsts);
4791 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4792 TPT.getRestorationPoint();
4793 while (!worklist.empty()) {
4794 Value *V = worklist.back();
4795 worklist.pop_back();
4796
4797 // We allow traversing cyclic Phi nodes.
4798 // In case of success after this loop we ensure that traversing through
4799 // Phi nodes ends up with all cases to compute address of the form
4800 // BaseGV + Base + Scale * Index + Offset
4801 // where Scale and Offset are constans and BaseGV, Base and Index
4802 // are exactly the same Values in all cases.
4803 // It means that BaseGV, Scale and Offset dominate our memory instruction
4804 // and have the same value as they had in address computation represented
4805 // as Phi. So we can safely sink address computation to memory instruction.
4806 if (!Visited.insert(V).second)
4807 continue;
4808
4809 // For a PHI node, push all of its incoming values.
4810 if (PHINode *P = dyn_cast<PHINode>(V)) {
4811 for (Value *IncValue : P->incoming_values())
4812 worklist.push_back(IncValue);
4813 PhiOrSelectSeen = true;
4814 continue;
4815 }
4816 // Similar for select.
4817 if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
4818 worklist.push_back(SI->getFalseValue());
4819 worklist.push_back(SI->getTrueValue());
4820 PhiOrSelectSeen = true;
4821 continue;
4822 }
4823
4824 // For non-PHIs, determine the addressing mode being computed. Note that
4825 // the result may differ depending on what other uses our candidate
4826 // addressing instructions might have.
4827 AddrModeInsts.clear();
4828 std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
4829 0);
4830 ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
4831 V, AccessTy, AddrSpace, MemoryInst, AddrModeInsts, *TLI, *TRI,
4832 InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI,
4833 BFI.get());
4834
4835 GetElementPtrInst *GEP = LargeOffsetGEP.first;
4836 if (GEP && !NewGEPBases.count(GEP)) {
4837 // If splitting the underlying data structure can reduce the offset of a
4838 // GEP, collect the GEP. Skip the GEPs that are the new bases of
4839 // previously split data structures.
4840 LargeOffsetGEPMap[GEP->getPointerOperand()].push_back(LargeOffsetGEP);
4841 if (LargeOffsetGEPID.find(GEP) == LargeOffsetGEPID.end())
4842 LargeOffsetGEPID[GEP] = LargeOffsetGEPID.size();
4843 }
4844
4845 NewAddrMode.OriginalValue = V;
4846 if (!AddrModes.addNewAddrMode(NewAddrMode))
4847 break;
4848 }
4849
4850 // Try to combine the AddrModes we've collected. If we couldn't collect any,
4851 // or we have multiple but either couldn't combine them or combining them
4852 // wouldn't do anything useful, bail out now.
4853 if (!AddrModes.combineAddrModes()) {
4854 TPT.rollback(LastKnownGood);
4855 return false;
4856 }
4857 TPT.commit();
4858
4859 // Get the combined AddrMode (or the only AddrMode, if we only had one).
4860 ExtAddrMode AddrMode = AddrModes.getAddrMode();
4861
4862 // If all the instructions matched are already in this BB, don't do anything.
4863 // If we saw a Phi node then it is not local definitely, and if we saw a select
4864 // then we want to push the address calculation past it even if it's already
4865 // in this BB.
4866 if (!PhiOrSelectSeen && none_of(AddrModeInsts, [&](Value *V) {
4867 return IsNonLocalValue(V, MemoryInst->getParent());
4868 })) {
4869 LLVM_DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Found local addrmode: "
<< AddrMode << "\n"; } } while (false)
4870 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Found local addrmode: "
<< AddrMode << "\n"; } } while (false)
;
4871 return false;
4872 }
4873
4874 // Insert this computation right after this user. Since our caller is
4875 // scanning from the top of the BB to the bottom, reuse of the expr are
4876 // guaranteed to happen later.
4877 IRBuilder<> Builder(MemoryInst);
4878
4879 // Now that we determined the addressing expression we want to use and know
4880 // that we have to sink it into this block. Check to see if we have already
4881 // done this for some other load/store instr in this block. If so, reuse
4882 // the computation. Before attempting reuse, check if the address is valid
4883 // as it may have been erased.
4884
4885 WeakTrackingVH SunkAddrVH = SunkAddrs[Addr];
4886
4887 Value * SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr;
4888 if (SunkAddr) {
4889 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)
4890 << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Reusing nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
4891 if (SunkAddr->getType() != Addr->getType())
4892 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
4893 } else if (AddrSinkUsingGEPs || (!AddrSinkUsingGEPs.getNumOccurrences() &&
4894 TM && SubtargetInfo->addrSinkUsingGEPs())) {
4895 // By default, we use the GEP-based method when AA is used later. This
4896 // prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
4897 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)
4898 << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
4899 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
4900 Value *ResultPtr = nullptr, *ResultIndex = nullptr;
4901
4902 // First, find the pointer.
4903 if (AddrMode.BaseReg && AddrMode.BaseReg->getType()->isPointerTy()) {
4904 ResultPtr = AddrMode.BaseReg;
4905 AddrMode.BaseReg = nullptr;
4906 }
4907
4908 if (AddrMode.Scale && AddrMode.ScaledReg->getType()->isPointerTy()) {
4909 // We can't add more than one pointer together, nor can we scale a
4910 // pointer (both of which seem meaningless).
4911 if (ResultPtr || AddrMode.Scale != 1)
4912 return false;
4913
4914 ResultPtr = AddrMode.ScaledReg;
4915 AddrMode.Scale = 0;
4916 }
4917
4918 // It is only safe to sign extend the BaseReg if we know that the math
4919 // required to create it did not overflow before we extend it. Since
4920 // the original IR value was tossed in favor of a constant back when
4921 // the AddrMode was created we need to bail out gracefully if widths
4922 // do not match instead of extending it.
4923 //
4924 // (See below for code to add the scale.)
4925 if (AddrMode.Scale) {
4926 Type *ScaledRegTy = AddrMode.ScaledReg->getType();
4927 if (cast<IntegerType>(IntPtrTy)->getBitWidth() >
4928 cast<IntegerType>(ScaledRegTy)->getBitWidth())
4929 return false;
4930 }
4931
4932 if (AddrMode.BaseGV) {
4933 if (ResultPtr)
4934 return false;
4935
4936 ResultPtr = AddrMode.BaseGV;
4937 }
4938
4939 // If the real base value actually came from an inttoptr, then the matcher
4940 // will look through it and provide only the integer value. In that case,
4941 // use it here.
4942 if (!DL->isNonIntegralPointerType(Addr->getType())) {
4943 if (!ResultPtr && AddrMode.BaseReg) {
4944 ResultPtr = Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(),
4945 "sunkaddr");
4946 AddrMode.BaseReg = nullptr;
4947 } else if (!ResultPtr && AddrMode.Scale == 1) {
4948 ResultPtr = Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(),
4949 "sunkaddr");
4950 AddrMode.Scale = 0;
4951 }
4952 }
4953
4954 if (!ResultPtr &&
4955 !AddrMode.BaseReg && !AddrMode.Scale && !AddrMode.BaseOffs) {
4956 SunkAddr = Constant::getNullValue(Addr->getType());
4957 } else if (!ResultPtr) {
4958 return false;
4959 } else {
4960 Type *I8PtrTy =
4961 Builder.getInt8PtrTy(Addr->getType()->getPointerAddressSpace());
4962 Type *I8Ty = Builder.getInt8Ty();
4963
4964 // Start with the base register. Do this first so that subsequent address
4965 // matching finds it last, which will prevent it from trying to match it
4966 // as the scaled value in case it happens to be a mul. That would be
4967 // problematic if we've sunk a different mul for the scale, because then
4968 // we'd end up sinking both muls.
4969 if (AddrMode.BaseReg) {
4970 Value *V = AddrMode.BaseReg;
4971 if (V->getType() != IntPtrTy)
4972 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
4973
4974 ResultIndex = V;
4975 }
4976
4977 // Add the scale value.
4978 if (AddrMode.Scale) {
4979 Value *V = AddrMode.ScaledReg;
4980 if (V->getType() == IntPtrTy) {
4981 // done.
4982 } else {
4983 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4985, __PRETTY_FUNCTION__))
4984 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4985, __PRETTY_FUNCTION__))
4985 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 4985, __PRETTY_FUNCTION__))
;
4986 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
4987 }
4988
4989 if (AddrMode.Scale != 1)
4990 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
4991 "sunkaddr");
4992 if (ResultIndex)
4993 ResultIndex = Builder.CreateAdd(ResultIndex, V, "sunkaddr");
4994 else
4995 ResultIndex = V;
4996 }
4997
4998 // Add in the Base Offset if present.
4999 if (AddrMode.BaseOffs) {
5000 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
5001 if (ResultIndex) {
5002 // We need to add this separately from the scale above to help with
5003 // SDAG consecutive load/store merging.
5004 if (ResultPtr->getType() != I8PtrTy)
5005 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
5006 ResultPtr =
5007 AddrMode.InBounds
5008 ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
5009 "sunkaddr")
5010 : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
5011 }
5012
5013 ResultIndex = V;
5014 }
5015
5016 if (!ResultIndex) {
5017 SunkAddr = ResultPtr;
5018 } else {
5019 if (ResultPtr->getType() != I8PtrTy)
5020 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
5021 SunkAddr =
5022 AddrMode.InBounds
5023 ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
5024 "sunkaddr")
5025 : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
5026 }
5027
5028 if (SunkAddr->getType() != Addr->getType())
5029 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
5030 }
5031 } else {
5032 // We'd require a ptrtoint/inttoptr down the line, which we can't do for
5033 // non-integral pointers, so in that case bail out now.
5034 Type *BaseTy = AddrMode.BaseReg ? AddrMode.BaseReg->getType() : nullptr;
5035 Type *ScaleTy = AddrMode.Scale ? AddrMode.ScaledReg->getType() : nullptr;
5036 PointerType *BasePtrTy = dyn_cast_or_null<PointerType>(BaseTy);
5037 PointerType *ScalePtrTy = dyn_cast_or_null<PointerType>(ScaleTy);
5038 if (DL->isNonIntegralPointerType(Addr->getType()) ||
5039 (BasePtrTy && DL->isNonIntegralPointerType(BasePtrTy)) ||
5040 (ScalePtrTy && DL->isNonIntegralPointerType(ScalePtrTy)) ||
5041 (AddrMode.BaseGV &&
5042 DL->isNonIntegralPointerType(AddrMode.BaseGV->getType())))
5043 return false;
5044
5045 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)
5046 << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
5047 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
5048 Value *Result = nullptr;
5049
5050 // Start with the base register. Do this first so that subsequent address
5051 // matching finds it last, which will prevent it from trying to match it
5052 // as the scaled value in case it happens to be a mul. That would be
5053 // problematic if we've sunk a different mul for the scale, because then
5054 // we'd end up sinking both muls.
5055 if (AddrMode.BaseReg) {
5056 Value *V = AddrMode.BaseReg;
5057 if (V->getType()->isPointerTy())
5058 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
5059 if (V->getType() != IntPtrTy)
5060 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
5061 Result = V;
5062 }
5063
5064 // Add the scale value.
5065 if (AddrMode.Scale) {
5066 Value *V = AddrMode.ScaledReg;
5067 if (V->getType() == IntPtrTy) {
5068 // done.
5069 } else if (V->getType()->isPointerTy()) {
5070 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
5071 } else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
5072 cast<IntegerType>(V->getType())->getBitWidth()) {
5073 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
5074 } else {
5075 // It is only safe to sign extend the BaseReg if we know that the math
5076 // required to create it did not overflow before we extend it. Since
5077 // the original IR value was tossed in favor of a constant back when
5078 // the AddrMode was created we need to bail out gracefully if widths
5079 // do not match instead of extending it.
5080 Instruction *I = dyn_cast_or_null<Instruction>(Result);
5081 if (I && (Result != AddrMode.BaseReg))
5082 I->eraseFromParent();
5083 return false;
5084 }
5085 if (AddrMode.Scale != 1)
5086 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
5087 "sunkaddr");
5088 if (Result)
5089 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5090 else
5091 Result = V;
5092 }
5093
5094 // Add in the BaseGV if present.
5095 if (AddrMode.BaseGV) {
5096 Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
5097 if (Result)
5098 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5099 else
5100 Result = V;
5101 }
5102
5103 // Add in the Base Offset if present.
5104 if (AddrMode.BaseOffs) {
5105 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
5106 if (Result)
5107 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5108 else
5109 Result = V;
5110 }
5111
5112 if (!Result)
5113 SunkAddr = Constant::getNullValue(Addr->getType());
5114 else
5115 SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr");
5116 }
5117
5118 MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
5119 // Store the newly computed address into the cache. In the case we reused a
5120 // value, this should be idempotent.
5121 SunkAddrs[Addr] = WeakTrackingVH(SunkAddr);
5122
5123 // If we have no uses, recursively delete the value and all dead instructions
5124 // using it.
5125 if (Repl->use_empty()) {
5126 // This can cause recursive deletion, which can invalidate our iterator.
5127 // Use a WeakTrackingVH to hold onto it in case this happens.
5128 Value *CurValue = &*CurInstIterator;
5129 WeakTrackingVH IterHandle(CurValue);
5130 BasicBlock *BB = CurInstIterator->getParent();
5131
5132 RecursivelyDeleteTriviallyDeadInstructions(Repl, TLInfo);
5133
5134 if (IterHandle != CurValue) {
5135 // If the iterator instruction was recursively deleted, start over at the
5136 // start of the block.
5137 CurInstIterator = BB->begin();
5138 SunkAddrs.clear();
5139 }
5140 }
5141 ++NumMemoryInsts;
5142 return true;
5143}
5144
5145/// If there are any memory operands, use OptimizeMemoryInst to sink their
5146/// address computing into the block when possible / profitable.
5147bool CodeGenPrepare::optimizeInlineAsmInst(CallInst *CS) {
5148 bool MadeChange = false;
5149
5150 const TargetRegisterInfo *TRI =
5151 TM->getSubtargetImpl(*CS->getFunction())->getRegisterInfo();
5152 TargetLowering::AsmOperandInfoVector TargetConstraints =
5153 TLI->ParseConstraints(*DL, TRI, CS);
5154 unsigned ArgNo = 0;
5155 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
5156 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
5157
5158 // Compute the constraint code and ConstraintType to use.
5159 TLI->ComputeConstraintToUse(OpInfo, SDValue());
5160
5161 if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
5162 OpInfo.isIndirect) {
5163 Value *OpVal = CS->getArgOperand(ArgNo++);
5164 MadeChange |= optimizeMemoryInst(CS, OpVal, OpVal->getType(), ~0u);
5165 } else if (OpInfo.Type == InlineAsm::isInput)
5166 ArgNo++;
5167 }
5168
5169 return MadeChange;
5170}
5171
5172/// Check if all the uses of \p Val are equivalent (or free) zero or
5173/// sign extensions.
5174static bool hasSameExtUse(Value *Val, const TargetLowering &TLI) {
5175 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5175, __PRETTY_FUNCTION__))
;
5176 const Instruction *FirstUser = cast<Instruction>(*Val->user_begin());
5177 bool IsSExt = isa<SExtInst>(FirstUser);
5178 Type *ExtTy = FirstUser->getType();
5179 for (const User *U : Val->users()) {
5180 const Instruction *UI = cast<Instruction>(U);
5181 if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI)))
5182 return false;
5183 Type *CurTy = UI->getType();
5184 // Same input and output types: Same instruction after CSE.
5185 if (CurTy == ExtTy)
5186 continue;
5187
5188 // If IsSExt is true, we are in this situation:
5189 // a = Val
5190 // b = sext ty1 a to ty2
5191 // c = sext ty1 a to ty3
5192 // Assuming ty2 is shorter than ty3, this could be turned into:
5193 // a = Val
5194 // b = sext ty1 a to ty2
5195 // c = sext ty2 b to ty3
5196 // However, the last sext is not free.
5197 if (IsSExt)
5198 return false;
5199
5200 // This is a ZExt, maybe this is free to extend from one type to another.
5201 // In that case, we would not account for a different use.
5202 Type *NarrowTy;
5203 Type *LargeTy;
5204 if (ExtTy->getScalarType()->getIntegerBitWidth() >
5205 CurTy->getScalarType()->getIntegerBitWidth()) {
5206 NarrowTy = CurTy;
5207 LargeTy = ExtTy;
5208 } else {
5209 NarrowTy = ExtTy;
5210 LargeTy = CurTy;
5211 }
5212
5213 if (!TLI.isZExtFree(NarrowTy, LargeTy))
5214 return false;
5215 }
5216 // All uses are the same or can be derived from one another for free.
5217 return true;
5218}
5219
5220/// Try to speculatively promote extensions in \p Exts and continue
5221/// promoting through newly promoted operands recursively as far as doing so is
5222/// profitable. Save extensions profitably moved up, in \p ProfitablyMovedExts.
5223/// When some promotion happened, \p TPT contains the proper state to revert
5224/// them.
5225///
5226/// \return true if some promotion happened, false otherwise.
5227bool CodeGenPrepare::tryToPromoteExts(
5228 TypePromotionTransaction &TPT, const SmallVectorImpl<Instruction *> &Exts,
5229 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
5230 unsigned CreatedInstsCost) {
5231 bool Promoted = false;
5232
5233 // Iterate over all the extensions to try to promote them.
5234 for (auto I : Exts) {
5235 // Early check if we directly have ext(load).
5236 if (isa<LoadInst>(I->getOperand(0))) {
5237 ProfitablyMovedExts.push_back(I);
5238 continue;
5239 }
5240
5241 // Check whether or not we want to do any promotion. The reason we have
5242 // this check inside the for loop is to catch the case where an extension
5243 // is directly fed by a load because in such case the extension can be moved
5244 // up without any promotion on its operands.
5245 if (!TLI || !TLI->enableExtLdPromotion() || DisableExtLdPromotion)
5246 return false;
5247
5248 // Get the action to perform the promotion.
5249 TypePromotionHelper::Action TPH =
5250 TypePromotionHelper::getAction(I, InsertedInsts, *TLI, PromotedInsts);
5251 // Check if we can promote.
5252 if (!TPH) {
5253 // Save the current extension as we cannot move up through its operand.
5254 ProfitablyMovedExts.push_back(I);
5255 continue;
5256 }
5257
5258 // Save the current state.
5259 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
5260 TPT.getRestorationPoint();
5261 SmallVector<Instruction *, 4> NewExts;
5262 unsigned NewCreatedInstsCost = 0;
5263 unsigned ExtCost = !TLI->isExtFree(I);
5264 // Promote.
5265 Value *PromotedVal = TPH(I, TPT, PromotedInsts, NewCreatedInstsCost,
5266 &NewExts, nullptr, *TLI);
5267 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5268, __PRETTY_FUNCTION__))
5268 "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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5268, __PRETTY_FUNCTION__))
;
5269
5270 // We would be able to merge only one extension in a load.
5271 // Therefore, if we have more than 1 new extension we heuristically
5272 // cut this search path, because it means we degrade the code quality.
5273 // With exactly 2, the transformation is neutral, because we will merge
5274 // one extension but leave one. However, we optimistically keep going,
5275 // because the new extension may be removed too.
5276 long long TotalCreatedInstsCost = CreatedInstsCost + NewCreatedInstsCost;
5277 // FIXME: It would be possible to propagate a negative value instead of
5278 // conservatively ceiling it to 0.
5279 TotalCreatedInstsCost =
5280 std::max((long long)0, (TotalCreatedInstsCost - ExtCost));
5281 if (!StressExtLdPromotion &&
5282 (TotalCreatedInstsCost > 1 ||
5283 !isPromotedInstructionLegal(*TLI, *DL, PromotedVal))) {
5284 // This promotion is not profitable, rollback to the previous state, and
5285 // save the current extension in ProfitablyMovedExts as the latest
5286 // speculative promotion turned out to be unprofitable.
5287 TPT.rollback(LastKnownGood);
5288 ProfitablyMovedExts.push_back(I);
5289 continue;
5290 }
5291 // Continue promoting NewExts as far as doing so is profitable.
5292 SmallVector<Instruction *, 2> NewlyMovedExts;
5293 (void)tryToPromoteExts(TPT, NewExts, NewlyMovedExts, TotalCreatedInstsCost);
5294 bool NewPromoted = false;
5295 for (auto ExtInst : NewlyMovedExts) {
5296 Instruction *MovedExt = cast<Instruction>(ExtInst);
5297 Value *ExtOperand = MovedExt->getOperand(0);
5298 // If we have reached to a load, we need this extra profitability check
5299 // as it could potentially be merged into an ext(load).
5300 if (isa<LoadInst>(ExtOperand) &&
5301 !(StressExtLdPromotion || NewCreatedInstsCost <= ExtCost ||
5302 (ExtOperand->hasOneUse() || hasSameExtUse(ExtOperand, *TLI))))
5303 continue;
5304
5305 ProfitablyMovedExts.push_back(MovedExt);
5306 NewPromoted = true;
5307 }
5308
5309 // If none of speculative promotions for NewExts is profitable, rollback
5310 // and save the current extension (I) as the last profitable extension.
5311 if (!NewPromoted) {
5312 TPT.rollback(LastKnownGood);
5313 ProfitablyMovedExts.push_back(I);
5314 continue;
5315 }
5316 // The promotion is profitable.
5317 Promoted = true;
5318 }
5319 return Promoted;
5320}
5321
5322/// Merging redundant sexts when one is dominating the other.
5323bool CodeGenPrepare::mergeSExts(Function &F) {
5324 bool Changed = false;
5325 for (auto &Entry : ValToSExtendedUses) {
5326 SExts &Insts = Entry.second;
5327 SExts CurPts;
5328 for (Instruction *Inst : Insts) {
5329 if (RemovedInsts.count(Inst) || !isa<SExtInst>(Inst) ||
5330 Inst->getOperand(0) != Entry.first)
5331 continue;
5332 bool inserted = false;
5333 for (auto &Pt : CurPts) {
5334 if (getDT(F).dominates(Inst, Pt)) {
5335 Pt->replaceAllUsesWith(Inst);
5336 RemovedInsts.insert(Pt);
5337 Pt->removeFromParent();
5338 Pt = Inst;
5339 inserted = true;
5340 Changed = true;
5341 break;
5342 }
5343 if (!getDT(F).dominates(Pt, Inst))
5344 // Give up if we need to merge in a common dominator as the
5345 // experiments show it is not profitable.
5346 continue;
5347 Inst->replaceAllUsesWith(Pt);
5348 RemovedInsts.insert(Inst);
5349 Inst->removeFromParent();
5350 inserted = true;
5351 Changed = true;
5352 break;
5353 }
5354 if (!inserted)
5355 CurPts.push_back(Inst);
5356 }
5357 }
5358 return Changed;
5359}
5360
5361// Spliting large data structures so that the GEPs accessing them can have
5362// smaller offsets so that they can be sunk to the same blocks as their users.
5363// For example, a large struct starting from %base is splitted into two parts
5364// where the second part starts from %new_base.
5365//
5366// Before:
5367// BB0:
5368// %base =
5369//
5370// BB1:
5371// %gep0 = gep %base, off0
5372// %gep1 = gep %base, off1
5373// %gep2 = gep %base, off2
5374//
5375// BB2:
5376// %load1 = load %gep0
5377// %load2 = load %gep1
5378// %load3 = load %gep2
5379//
5380// After:
5381// BB0:
5382// %base =
5383// %new_base = gep %base, off0
5384//
5385// BB1:
5386// %new_gep0 = %new_base
5387// %new_gep1 = gep %new_base, off1 - off0
5388// %new_gep2 = gep %new_base, off2 - off0
5389//
5390// BB2:
5391// %load1 = load i32, i32* %new_gep0
5392// %load2 = load i32, i32* %new_gep1
5393// %load3 = load i32, i32* %new_gep2
5394//
5395// %new_gep1 and %new_gep2 can be sunk to BB2 now after the splitting because
5396// their offsets are smaller enough to fit into the addressing mode.
5397bool CodeGenPrepare::splitLargeGEPOffsets() {
5398 bool Changed = false;
5399 for (auto &Entry : LargeOffsetGEPMap) {
5400 Value *OldBase = Entry.first;
5401 SmallVectorImpl<std::pair<AssertingVH<GetElementPtrInst>, int64_t>>
5402 &LargeOffsetGEPs = Entry.second;
5403 auto compareGEPOffset =
5404 [&](const std::pair<GetElementPtrInst *, int64_t> &LHS,
5405 const std::pair<GetElementPtrInst *, int64_t> &RHS) {
5406 if (LHS.first == RHS.first)
5407 return false;
5408 if (LHS.second != RHS.second)
5409 return LHS.second < RHS.second;
5410 return LargeOffsetGEPID[LHS.first] < LargeOffsetGEPID[RHS.first];
5411 };
5412 // Sorting all the GEPs of the same data structures based on the offsets.
5413 llvm::sort(LargeOffsetGEPs, compareGEPOffset);
5414 LargeOffsetGEPs.erase(
5415 std::unique(LargeOffsetGEPs.begin(), LargeOffsetGEPs.end()),
5416 LargeOffsetGEPs.end());
5417 // Skip if all the GEPs have the same offsets.
5418 if (LargeOffsetGEPs.front().second == LargeOffsetGEPs.back().second)
5419 continue;
5420 GetElementPtrInst *BaseGEP = LargeOffsetGEPs.begin()->first;
5421 int64_t BaseOffset = LargeOffsetGEPs.begin()->second;
5422 Value *NewBaseGEP = nullptr;
5423
5424 auto LargeOffsetGEP = LargeOffsetGEPs.begin();
5425 while (LargeOffsetGEP != LargeOffsetGEPs.end()) {
5426 GetElementPtrInst *GEP = LargeOffsetGEP->first;
5427 int64_t Offset = LargeOffsetGEP->second;
5428 if (Offset != BaseOffset) {
5429 TargetLowering::AddrMode AddrMode;
5430 AddrMode.BaseOffs = Offset - BaseOffset;
5431 // The result type of the GEP might not be the type of the memory
5432 // access.
5433 if (!TLI->isLegalAddressingMode(*DL, AddrMode,
5434 GEP->getResultElementType(),
5435 GEP->getAddressSpace())) {
5436 // We need to create a new base if the offset to the current base is
5437 // too large to fit into the addressing mode. So, a very large struct
5438 // may be splitted into several parts.
5439 BaseGEP = GEP;
5440 BaseOffset = Offset;
5441 NewBaseGEP = nullptr;
5442 }
5443 }
5444
5445 // Generate a new GEP to replace the current one.
5446 LLVMContext &Ctx = GEP->getContext();
5447 Type *IntPtrTy = DL->getIntPtrType(GEP->getType());
5448 Type *I8PtrTy =
5449 Type::getInt8PtrTy(Ctx, GEP->getType()->getPointerAddressSpace());
5450 Type *I8Ty = Type::getInt8Ty(Ctx);
5451
5452 if (!NewBaseGEP) {
5453 // Create a new base if we don't have one yet. Find the insertion
5454 // pointer for the new base first.
5455 BasicBlock::iterator NewBaseInsertPt;
5456 BasicBlock *NewBaseInsertBB;
5457 if (auto *BaseI = dyn_cast<Instruction>(OldBase)) {
5458 // If the base of the struct is an instruction, the new base will be
5459 // inserted close to it.
5460 NewBaseInsertBB = BaseI->getParent();
5461 if (isa<PHINode>(BaseI))
5462 NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
5463 else if (InvokeInst *Invoke = dyn_cast<InvokeInst>(BaseI)) {
5464 NewBaseInsertBB =
5465 SplitEdge(NewBaseInsertBB, Invoke->getNormalDest());
5466 NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
5467 } else
5468 NewBaseInsertPt = std::next(BaseI->getIterator());
5469 } else {
5470 // If the current base is an argument or global value, the new base
5471 // will be inserted to the entry block.
5472 NewBaseInsertBB = &BaseGEP->getFunction()->getEntryBlock();
5473 NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
5474 }
5475 IRBuilder<> NewBaseBuilder(NewBaseInsertBB, NewBaseInsertPt);
5476 // Create a new base.
5477 Value *BaseIndex = ConstantInt::get(IntPtrTy, BaseOffset);
5478 NewBaseGEP = OldBase;
5479 if (NewBaseGEP->getType() != I8PtrTy)
5480 NewBaseGEP = NewBaseBuilder.CreatePointerCast(NewBaseGEP, I8PtrTy);
5481 NewBaseGEP =
5482 NewBaseBuilder.CreateGEP(I8Ty, NewBaseGEP, BaseIndex, "splitgep");
5483 NewGEPBases.insert(NewBaseGEP);
5484 }
5485
5486 IRBuilder<> Builder(GEP);
5487 Value *NewGEP = NewBaseGEP;
5488 if (Offset == BaseOffset) {
5489 if (GEP->getType() != I8PtrTy)
5490 NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType());
5491 } else {
5492 // Calculate the new offset for the new GEP.
5493 Value *Index = ConstantInt::get(IntPtrTy, Offset - BaseOffset);
5494 NewGEP = Builder.CreateGEP(I8Ty, NewBaseGEP, Index);
5495
5496 if (GEP->getType() != I8PtrTy)
5497 NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType());
5498 }
5499 GEP->replaceAllUsesWith(NewGEP);
5500 LargeOffsetGEPID.erase(GEP);
5501 LargeOffsetGEP = LargeOffsetGEPs.erase(LargeOffsetGEP);
5502 GEP->eraseFromParent();
5503 Changed = true;
5504 }
5505 }
5506 return Changed;
5507}
5508
5509/// Return true, if an ext(load) can be formed from an extension in
5510/// \p MovedExts.
5511bool CodeGenPrepare::canFormExtLd(
5512 const SmallVectorImpl<Instruction *> &MovedExts, LoadInst *&LI,
5513 Instruction *&Inst, bool HasPromoted) {
5514 for (auto *MovedExtInst : MovedExts) {
5515 if (isa<LoadInst>(MovedExtInst->getOperand(0))) {
5516 LI = cast<LoadInst>(MovedExtInst->getOperand(0));
5517 Inst = MovedExtInst;
5518 break;
5519 }
5520 }
5521 if (!LI)
5522 return false;
5523
5524 // If they're already in the same block, there's nothing to do.
5525 // Make the cheap checks first if we did not promote.
5526 // If we promoted, we need to check if it is indeed profitable.
5527 if (!HasPromoted && LI->getParent() == Inst->getParent())
5528 return false;
5529
5530 return TLI->isExtLoad(LI, Inst, *DL);
5531}
5532
5533/// Move a zext or sext fed by a load into the same basic block as the load,
5534/// unless conditions are unfavorable. This allows SelectionDAG to fold the
5535/// extend into the load.
5536///
5537/// E.g.,
5538/// \code
5539/// %ld = load i32* %addr
5540/// %add = add nuw i32 %ld, 4
5541/// %zext = zext i32 %add to i64
5542// \endcode
5543/// =>
5544/// \code
5545/// %ld = load i32* %addr
5546/// %zext = zext i32 %ld to i64
5547/// %add = add nuw i64 %zext, 4
5548/// \encode
5549/// Note that the promotion in %add to i64 is done in tryToPromoteExts(), which
5550/// allow us to match zext(load i32*) to i64.
5551///
5552/// Also, try to promote the computations used to obtain a sign extended
5553/// value used into memory accesses.
5554/// E.g.,
5555/// \code
5556/// a = add nsw i32 b, 3
5557/// d = sext i32 a to i64
5558/// e = getelementptr ..., i64 d
5559/// \endcode
5560/// =>
5561/// \code
5562/// f = sext i32 b to i64
5563/// a = add nsw i64 f, 3
5564/// e = getelementptr ..., i64 a
5565/// \endcode
5566///
5567/// \p Inst[in/out] the extension may be modified during the process if some
5568/// promotions apply.
5569bool CodeGenPrepare::optimizeExt(Instruction *&Inst) {
5570 // ExtLoad formation and address type promotion infrastructure requires TLI to
5571 // be effective.
5572 if (!TLI)
5573 return false;
5574
5575 bool AllowPromotionWithoutCommonHeader = false;
5576 /// See if it is an interesting sext operations for the address type
5577 /// promotion before trying to promote it, e.g., the ones with the right
5578 /// type and used in memory accesses.
5579 bool ATPConsiderable = TTI->shouldConsiderAddressTypePromotion(
5580 *Inst, AllowPromotionWithoutCommonHeader);
5581 TypePromotionTransaction TPT(RemovedInsts);
5582 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
5583 TPT.getRestorationPoint();
5584 SmallVector<Instruction *, 1> Exts;
5585 SmallVector<Instruction *, 2> SpeculativelyMovedExts;
5586 Exts.push_back(Inst);
5587
5588 bool HasPromoted = tryToPromoteExts(TPT, Exts, SpeculativelyMovedExts);
5589
5590 // Look for a load being extended.
5591 LoadInst *LI = nullptr;
5592 Instruction *ExtFedByLoad;
5593
5594 // Try to promote a chain of computation if it allows to form an extended
5595 // load.
5596 if (canFormExtLd(SpeculativelyMovedExts, LI, ExtFedByLoad, HasPromoted)) {
5597 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-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5597, __PRETTY_FUNCTION__))
;
5598 TPT.commit();
5599 // Move the extend into the same block as the load
5600 ExtFedByLoad->moveAfter(LI);
5601 // CGP does not check if the zext would be speculatively executed when moved
5602 // to the same basic block as the load. Preserving its original location
5603 // would pessimize the debugging experience, as well as negatively impact
5604 // the quality of sample pgo. We don't want to use "line 0" as that has a
5605 // size cost in the line-table section and logically the zext can be seen as
5606 // part of the load. Therefore we conservatively reuse the same debug
5607 // location for the load and the zext.
5608 ExtFedByLoad->setDebugLoc(LI->getDebugLoc());
5609 ++NumExtsMoved;
5610 Inst = ExtFedByLoad;
5611 return true;
5612 }
5613
5614 // Continue promoting SExts if known as considerable depending on targets.
5615 if (ATPConsiderable &&
5616 performAddressTypePromotion(Inst, AllowPromotionWithoutCommonHeader,
5617 HasPromoted, TPT, SpeculativelyMovedExts))
5618 return true;
5619
5620 TPT.rollback(LastKnownGood);
5621 return false;
5622}
5623
5624// Perform address type promotion if doing so is profitable.
5625// If AllowPromotionWithoutCommonHeader == false, we should find other sext
5626// instructions that sign extended the same initial value. However, if
5627// AllowPromotionWithoutCommonHeader == true, we expect promoting the
5628// extension is just profitable.
5629bool CodeGenPrepare::performAddressTypePromotion(
5630 Instruction *&Inst, bool AllowPromotionWithoutCommonHeader,
5631 bool HasPromoted, TypePromotionTransaction &TPT,
5632 SmallVectorImpl<Instruction *> &SpeculativelyMovedExts) {
5633 bool Promoted = false;
5634 SmallPtrSet<Instruction *, 1> UnhandledExts;
5635 bool AllSeenFirst = true;
5636 for (auto I : SpeculativelyMovedExts) {
5637 Value *HeadOfChain = I->getOperand(0);
5638 DenseMap<Value *, Instruction *>::iterator AlreadySeen =
5639 SeenChainsForSExt.find(HeadOfChain);
5640 // If there is an unhandled SExt which has the same header, try to promote
5641 // it as well.
5642 if (AlreadySeen != SeenChainsForSExt.end()) {
5643 if (AlreadySeen->second != nullptr)
5644 UnhandledExts.insert(AlreadySeen->second);
5645 AllSeenFirst = false;
5646 }
5647 }
5648
5649 if (!AllSeenFirst || (AllowPromotionWithoutCommonHeader &&
5650 SpeculativelyMovedExts.size() == 1)) {
5651 TPT.commit();
5652 if (HasPromoted)
5653 Promoted = true;
5654 for (auto I : SpeculativelyMovedExts) {
5655 Value *HeadOfChain = I->getOperand(0);
5656 SeenChainsForSExt[HeadOfChain] = nullptr;
5657 ValToSExtendedUses[HeadOfChain].push_back(I);
5658 }
5659 // Update Inst as promotion happen.
5660 Inst = SpeculativelyMovedExts.pop_back_val();
5661 } else {
5662 // This is the first chain visited from the header, keep the current chain
5663 // as unhandled. Defer to promote this until we encounter another SExt
5664 // chain derived from the same header.
5665 for (auto I : SpeculativelyMovedExts) {
5666 Value *HeadOfChain = I->getOperand(0);
5667 SeenChainsForSExt[HeadOfChain] = Inst;
5668 }
5669 return false;
5670 }
5671
5672 if (!AllSeenFirst && !UnhandledExts.empty())
5673 for (auto VisitedSExt : UnhandledExts) {
5674 if (RemovedInsts.count(VisitedSExt))
5675 continue;
5676 TypePromotionTransaction TPT(RemovedInsts);
5677 SmallVector<Instruction *, 1> Exts;
5678 SmallVector<Instruction *, 2> Chains;
5679 Exts.push_back(VisitedSExt);
5680 bool HasPromoted = tryToPromoteExts(TPT, Exts, Chains);
5681 TPT.commit();
5682 if (HasPromoted)
5683 Promoted = true;
5684 for (auto I : Chains) {
5685 Value *HeadOfChain = I->getOperand(0);
5686 // Mark this as handled.
5687 SeenChainsForSExt[HeadOfChain] = nullptr;
5688 ValToSExtendedUses[HeadOfChain].push_back(I);
5689 }
5690 }
5691 return Promoted;
5692}
5693
5694bool CodeGenPrepare::optimizeExtUses(Instruction *I) {
5695 BasicBlock *DefBB = I->getParent();
5696
5697 // If the result of a {s|z}ext and its source are both live out, rewrite all
5698 // other uses of the source with result of extension.
5699 Value *Src = I->getOperand(0);
5700 if (Src->hasOneUse())
5701 return false;
5702
5703 // Only do this xform if truncating is free.
5704 if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
5705 return false;
5706
5707 // Only safe to perform the optimization if the source is also defined in
5708 // this block.
5709 if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
5710 return false;
5711
5712 bool DefIsLiveOut = false;
5713 for (User *U : I->users()) {
5714 Instruction *UI = cast<Instruction>(U);
5715
5716 // Figure out which BB this ext is used in.
5717 BasicBlock *UserBB = UI->getParent();
5718 if (UserBB == DefBB) continue;
5719 DefIsLiveOut = true;
5720 break;
5721 }
5722 if (!DefIsLiveOut)
5723 return false;
5724
5725 // Make sure none of the uses are PHI nodes.
5726 for (User *U : Src->users()) {
5727 Instruction *UI = cast<Instruction>(U);
5728 BasicBlock *UserBB = UI->getParent();
5729 if (UserBB == DefBB) continue;
5730 // Be conservative. We don't want this xform to end up introducing
5731 // reloads just before load / store instructions.
5732 if (isa<PHINode>(UI) || isa<LoadInst>(UI) || isa<StoreInst>(UI))
5733 return false;
5734 }
5735
5736 // InsertedTruncs - Only insert one trunc in each block once.
5737 DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
5738
5739 bool MadeChange = false;
5740 for (Use &U : Src->uses()) {
5741 Instruction *User = cast<Instruction>(U.getUser());
5742
5743 // Figure out which BB this ext is used in.
5744 BasicBlock *UserBB = User->getParent();
5745 if (UserBB == DefBB) continue;
5746
5747 // Both src and def are live in this block. Rewrite the use.
5748 Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
5749
5750 if (!InsertedTrunc) {
5751 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
5752 assert(InsertPt != UserBB->end())((InsertPt != UserBB->end()) ? static_cast<void> (0)
: __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-10~++20200112100611+7fa5290d5bd/llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 5752, __PRETTY_FUNCTION__))
;
5753 InsertedTrunc = new TruncInst(I, Src->getType(), "", &*InsertPt);
5754 InsertedInsts.insert(InsertedTrunc);
5755 }
5756
5757 // Replace a use of the {s|z}ext source with a use of the result.
5758 U = InsertedTrunc;
5759 ++NumExtUses;
5760 MadeChange = true;
5761 }
5762
5763 return MadeChange;
5764}
5765
5766// Find loads whose uses only use some of the loaded value's bits. Add an "and"
5767// just after the load if the target can fold this into one extload instruction,
5768// with the hope of eliminating some of the other later "and" instructions using
5769// the loaded value. "and"s that are made trivially redundant by the insertion
5770// of the new "and" are removed by this function, while others (e.g. those whose
5771// path from the load goes through a phi) are left for isel to potentially
5772// remove.
5773//
5774// For example:
5775//
5776// b0:
5777// x = load i32
5778// ...
5779// b1:
5780// y = and x, 0xff
5781// z = use y
5782//
5783// becomes:
5784//
5785// b0:
5786// x = load i32
5787// x' = and x, 0xff
5788// ...
5789// b1:
5790// z = use x'
5791//
5792// whereas:
5793//
5794// b0:
5795// x1 = load i32
5796// ...
5797// b1:
5798// x2 = load i32
5799// ...
5800// b2:
5801// x = phi x1, x2
5802// y = and x, 0xff
5803//
5804// becomes (after a call to optimizeLoadExt for each load):
5805//
5806// b0:
5807// x1 = load i32
5808// x1' = and x1, 0xff
5809// ...
5810// b1:
5811// x2 = load i32
5812// x2' = and x2, 0xff
5813// ...
5814// b2:
5815// x = phi x1', x2'
5816// y = and x, 0xff
5817bool CodeGenPrepare::optimizeLoadExt(LoadInst *Load) {
5818 if (!Load->isSimple() || !Load->getType()->isIntOrPtrTy())
5819 return false;
5820
5821 // Skip loads we've already transformed.
5822 if (Load->hasOneUse() &&
5823 InsertedInsts.count(cast<Instruction>(*Load->user_begin())))
5824 return false;
5825
5826 // Look at all uses of Load, looking through phis, to determine how many bits
5827 // of the loaded value are needed.
5828 SmallVector<Instruction *, 8> WorkList;
5829 SmallPtrSet<Instruction *, 16> Visited;
5830 SmallVector<Instruction *, 8> AndsToMaybeRemove;
5831 for (auto *U : Load->users())
5832 WorkList.push_back(cast<Instruction>(U));
5833
5834 EVT LoadResultVT = TLI->getValueType(*DL, Load->getType());