Bug Summary

File:llvm/lib/CodeGen/CodeGenPrepare.cpp
Warning:line 1134, column 37
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -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 -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/CodeGen -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/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-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/CodeGen -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/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/Constant.h"
47#include "llvm/IR/Constants.h"
48#include "llvm/IR/DataLayout.h"
49#include "llvm/IR/DebugInfo.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/LLVMContext.h"
65#include "llvm/IR/MDBuilder.h"
66#include "llvm/IR/Module.h"
67#include "llvm/IR/Operator.h"
68#include "llvm/IR/PatternMatch.h"
69#include "llvm/IR/Statepoint.h"
70#include "llvm/IR/Type.h"
71#include "llvm/IR/Use.h"
72#include "llvm/IR/User.h"
73#include "llvm/IR/Value.h"
74#include "llvm/IR/ValueHandle.h"
75#include "llvm/IR/ValueMap.h"
76#include "llvm/InitializePasses.h"
77#include "llvm/Pass.h"
78#include "llvm/Support/BlockFrequency.h"
79#include "llvm/Support/BranchProbability.h"
80#include "llvm/Support/Casting.h"
81#include "llvm/Support/CommandLine.h"
82#include "llvm/Support/Compiler.h"
83#include "llvm/Support/Debug.h"
84#include "llvm/Support/ErrorHandling.h"
85#include "llvm/Support/MachineValueType.h"
86#include "llvm/Support/MathExtras.h"
87#include "llvm/Support/raw_ostream.h"
88#include "llvm/Target/TargetMachine.h"
89#include "llvm/Target/TargetOptions.h"
90#include "llvm/Transforms/Utils/BasicBlockUtils.h"
91#include "llvm/Transforms/Utils/BypassSlowDivision.h"
92#include "llvm/Transforms/Utils/Local.h"
93#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
94#include "llvm/Transforms/Utils/SizeOpts.h"
95#include <algorithm>
96#include <cassert>
97#include <cstdint>
98#include <iterator>
99#include <limits>
100#include <memory>
101#include <utility>
102#include <vector>
103
104using namespace llvm;
105using namespace llvm::PatternMatch;
106
107#define DEBUG_TYPE"codegenprepare" "codegenprepare"
108
109STATISTIC(NumBlocksElim, "Number of blocks eliminated")static llvm::Statistic NumBlocksElim = {"codegenprepare", "NumBlocksElim"
, "Number of blocks eliminated"}
;
110STATISTIC(NumPHIsElim, "Number of trivial PHIs eliminated")static llvm::Statistic NumPHIsElim = {"codegenprepare", "NumPHIsElim"
, "Number of trivial PHIs eliminated"}
;
111STATISTIC(NumGEPsElim, "Number of GEPs converted to casts")static llvm::Statistic NumGEPsElim = {"codegenprepare", "NumGEPsElim"
, "Number of GEPs converted to casts"}
;
112STATISTIC(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"
}
113 "sunken Cmps")static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses"
, "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps"
}
;
114STATISTIC(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"
}
115 "of sunken Casts")static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses"
, "Number of uses of Cast expressions replaced with uses " "of sunken Casts"
}
;
116STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
}
117 "computations were sunk")static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
}
;
118STATISTIC(NumMemoryInstsPhiCreated,static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions"}
119 "Number of phis created when address "static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions"}
120 "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions"}
;
121STATISTIC(NumMemoryInstsSelectCreated,static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions"}
122 "Number of select created when address "static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions"}
123 "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions"}
;
124STATISTIC(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"}
;
125STATISTIC(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"}
;
126STATISTIC(NumAndsAdded,static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded"
, "Number of and mask instructions added to form ext loads"}
127 "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"}
;
128STATISTIC(NumAndUses, "Number of uses of and mask instructions optimized")static llvm::Statistic NumAndUses = {"codegenprepare", "NumAndUses"
, "Number of uses of and mask instructions optimized"}
;
129STATISTIC(NumRetsDup, "Number of return instructions duplicated")static llvm::Statistic NumRetsDup = {"codegenprepare", "NumRetsDup"
, "Number of return instructions duplicated"}
;
130STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved")static llvm::Statistic NumDbgValueMoved = {"codegenprepare", "NumDbgValueMoved"
, "Number of debug value instructions moved"}
;
131STATISTIC(NumSelectsExpanded, "Number of selects turned into branches")static llvm::Statistic NumSelectsExpanded = {"codegenprepare"
, "NumSelectsExpanded", "Number of selects turned into branches"
}
;
132STATISTIC(NumStoreExtractExposed, "Number of store(extractelement) exposed")static llvm::Statistic NumStoreExtractExposed = {"codegenprepare"
, "NumStoreExtractExposed", "Number of store(extractelement) exposed"
}
;
133
134static cl::opt<bool> DisableBranchOpts(
135 "disable-cgp-branch-opts", cl::Hidden, cl::init(false),
136 cl::desc("Disable branch optimizations in CodeGenPrepare"));
137
138static cl::opt<bool>
139 DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false),
140 cl::desc("Disable GC optimizations in CodeGenPrepare"));
141
142static cl::opt<bool> DisableSelectToBranch(
143 "disable-cgp-select2branch", cl::Hidden, cl::init(false),
144 cl::desc("Disable select to branch conversion."));
145
146static cl::opt<bool> AddrSinkUsingGEPs(
147 "addr-sink-using-gep", cl::Hidden, cl::init(true),
148 cl::desc("Address sinking in CGP using GEPs."));
149
150static cl::opt<bool> EnableAndCmpSinking(
151 "enable-andcmp-sinking", cl::Hidden, cl::init(true),
152 cl::desc("Enable sinkinig and/cmp into branches."));
153
154static cl::opt<bool> DisableStoreExtract(
155 "disable-cgp-store-extract", cl::Hidden, cl::init(false),
156 cl::desc("Disable store(extract) optimizations in CodeGenPrepare"));
157
158static cl::opt<bool> StressStoreExtract(
159 "stress-cgp-store-extract", cl::Hidden, cl::init(false),
160 cl::desc("Stress test store(extract) optimizations in CodeGenPrepare"));
161
162static cl::opt<bool> DisableExtLdPromotion(
163 "disable-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
164 cl::desc("Disable ext(promotable(ld)) -> promoted(ext(ld)) optimization in "
165 "CodeGenPrepare"));
166
167static cl::opt<bool> StressExtLdPromotion(
168 "stress-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
169 cl::desc("Stress test ext(promotable(ld)) -> promoted(ext(ld)) "
170 "optimization in CodeGenPrepare"));
171
172static cl::opt<bool> DisablePreheaderProtect(
173 "disable-preheader-prot", cl::Hidden, cl::init(false),
174 cl::desc("Disable protection against removing loop preheaders"));
175
176static cl::opt<bool> ProfileGuidedSectionPrefix(
177 "profile-guided-section-prefix", cl::Hidden, cl::init(true), cl::ZeroOrMore,
178 cl::desc("Use profile info to add section prefix for hot/cold functions"));
179
180static cl::opt<bool> ProfileUnknownInSpecialSection(
181 "profile-unknown-in-special-section", cl::Hidden, cl::init(false),
182 cl::ZeroOrMore,
183 cl::desc("In profiling mode like sampleFDO, if a function doesn't have "
184 "profile, we cannot tell the function is cold for sure because "
185 "it may be a function newly added without ever being sampled. "
186 "With the flag enabled, compiler can put such profile unknown "
187 "functions into a special section, so runtime system can choose "
188 "to handle it in a different way than .text section, to save "
189 "RAM for example. "));
190
191static cl::opt<unsigned> FreqRatioToSkipMerge(
192 "cgp-freq-ratio-to-skip-merge", cl::Hidden, cl::init(2),
193 cl::desc("Skip merging empty blocks if (frequency of empty block) / "
194 "(frequency of destination block) is greater than this ratio"));
195
196static cl::opt<bool> ForceSplitStore(
197 "force-split-store", cl::Hidden, cl::init(false),
198 cl::desc("Force store splitting no matter what the target query says."));
199
200static cl::opt<bool>
201EnableTypePromotionMerge("cgp-type-promotion-merge", cl::Hidden,
202 cl::desc("Enable merging of redundant sexts when one is dominating"
203 " the other."), cl::init(true));
204
205static cl::opt<bool> DisableComplexAddrModes(
206 "disable-complex-addr-modes", cl::Hidden, cl::init(false),
207 cl::desc("Disables combining addressing modes with different parts "
208 "in optimizeMemoryInst."));
209
210static cl::opt<bool>
211AddrSinkNewPhis("addr-sink-new-phis", cl::Hidden, cl::init(false),
212 cl::desc("Allow creation of Phis in Address sinking."));
213
214static cl::opt<bool>
215AddrSinkNewSelects("addr-sink-new-select", cl::Hidden, cl::init(true),
216 cl::desc("Allow creation of selects in Address sinking."));
217
218static cl::opt<bool> AddrSinkCombineBaseReg(
219 "addr-sink-combine-base-reg", cl::Hidden, cl::init(true),
220 cl::desc("Allow combining of BaseReg field in Address sinking."));
221
222static cl::opt<bool> AddrSinkCombineBaseGV(
223 "addr-sink-combine-base-gv", cl::Hidden, cl::init(true),
224 cl::desc("Allow combining of BaseGV field in Address sinking."));
225
226static cl::opt<bool> AddrSinkCombineBaseOffs(
227 "addr-sink-combine-base-offs", cl::Hidden, cl::init(true),
228 cl::desc("Allow combining of BaseOffs field in Address sinking."));
229
230static cl::opt<bool> AddrSinkCombineScaledReg(
231 "addr-sink-combine-scaled-reg", cl::Hidden, cl::init(true),
232 cl::desc("Allow combining of ScaledReg field in Address sinking."));
233
234static cl::opt<bool>
235 EnableGEPOffsetSplit("cgp-split-large-offset-gep", cl::Hidden,
236 cl::init(true),
237 cl::desc("Enable splitting large offset of GEP."));
238
239static cl::opt<bool> EnableICMP_EQToICMP_ST(
240 "cgp-icmp-eq2icmp-st", cl::Hidden, cl::init(false),
241 cl::desc("Enable ICMP_EQ to ICMP_S(L|G)T conversion."));
242
243static cl::opt<bool>
244 VerifyBFIUpdates("cgp-verify-bfi-updates", cl::Hidden, cl::init(false),
245 cl::desc("Enable BFI update verification for "
246 "CodeGenPrepare."));
247
248static cl::opt<bool> OptimizePhiTypes(
249 "cgp-optimize-phi-types", cl::Hidden, cl::init(false),
250 cl::desc("Enable converting phi types in CodeGenPrepare"));
251
252namespace {
253
254enum ExtType {
255 ZeroExtension, // Zero extension has been seen.
256 SignExtension, // Sign extension has been seen.
257 BothExtension // This extension type is used if we saw sext after
258 // ZeroExtension had been set, or if we saw zext after
259 // SignExtension had been set. It makes the type
260 // information of a promoted instruction invalid.
261};
262
263using SetOfInstrs = SmallPtrSet<Instruction *, 16>;
264using TypeIsSExt = PointerIntPair<Type *, 2, ExtType>;
265using InstrToOrigTy = DenseMap<Instruction *, TypeIsSExt>;
266using SExts = SmallVector<Instruction *, 16>;
267using ValueToSExts = DenseMap<Value *, SExts>;
268
269class TypePromotionTransaction;
270
271 class CodeGenPrepare : public FunctionPass {
272 const TargetMachine *TM = nullptr;
273 const TargetSubtargetInfo *SubtargetInfo;
274 const TargetLowering *TLI = nullptr;
275 const TargetRegisterInfo *TRI;
276 const TargetTransformInfo *TTI = nullptr;
277 const TargetLibraryInfo *TLInfo;
278 const LoopInfo *LI;
279 std::unique_ptr<BlockFrequencyInfo> BFI;
280 std::unique_ptr<BranchProbabilityInfo> BPI;
281 ProfileSummaryInfo *PSI;
282
283 /// As we scan instructions optimizing them, this is the next instruction
284 /// to optimize. Transforms that can invalidate this should update it.
285 BasicBlock::iterator CurInstIterator;
286
287 /// Keeps track of non-local addresses that have been sunk into a block.
288 /// This allows us to avoid inserting duplicate code for blocks with
289 /// multiple load/stores of the same address. The usage of WeakTrackingVH
290 /// enables SunkAddrs to be treated as a cache whose entries can be
291 /// invalidated if a sunken address computation has been erased.
292 ValueMap<Value*, WeakTrackingVH> SunkAddrs;
293
294 /// Keeps track of all instructions inserted for the current function.
295 SetOfInstrs InsertedInsts;
296
297 /// Keeps track of the type of the related instruction before their
298 /// promotion for the current function.
299 InstrToOrigTy PromotedInsts;
300
301 /// Keep track of instructions removed during promotion.
302 SetOfInstrs RemovedInsts;
303
304 /// Keep track of sext chains based on their initial value.
305 DenseMap<Value *, Instruction *> SeenChainsForSExt;
306
307 /// Keep track of GEPs accessing the same data structures such as structs or
308 /// arrays that are candidates to be split later because of their large
309 /// size.
310 MapVector<
311 AssertingVH<Value>,
312 SmallVector<std::pair<AssertingVH<GetElementPtrInst>, int64_t>, 32>>
313 LargeOffsetGEPMap;
314
315 /// Keep track of new GEP base after splitting the GEPs having large offset.
316 SmallSet<AssertingVH<Value>, 2> NewGEPBases;
317
318 /// Map serial numbers to Large offset GEPs.
319 DenseMap<AssertingVH<GetElementPtrInst>, int> LargeOffsetGEPID;
320
321 /// Keep track of SExt promoted.
322 ValueToSExts ValToSExtendedUses;
323
324 /// True if the function has the OptSize attribute.
325 bool OptSize;
326
327 /// DataLayout for the Function being processed.
328 const DataLayout *DL = nullptr;
329
330 /// Building the dominator tree can be expensive, so we only build it
331 /// lazily and update it when required.
332 std::unique_ptr<DominatorTree> DT;
333
334 public:
335 static char ID; // Pass identification, replacement for typeid
336
337 CodeGenPrepare() : FunctionPass(ID) {
338 initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
339 }
340
341 bool runOnFunction(Function &F) override;
342
343 StringRef getPassName() const override { return "CodeGen Prepare"; }
344
345 void getAnalysisUsage(AnalysisUsage &AU) const override {
346 // FIXME: When we can selectively preserve passes, preserve the domtree.
347 AU.addRequired<ProfileSummaryInfoWrapperPass>();
348 AU.addRequired<TargetLibraryInfoWrapperPass>();
349 AU.addRequired<TargetPassConfig>();
350 AU.addRequired<TargetTransformInfoWrapperPass>();
351 AU.addRequired<LoopInfoWrapperPass>();
352 }
353
354 private:
355 template <typename F>
356 void resetIteratorIfInvalidatedWhileCalling(BasicBlock *BB, F f) {
357 // Substituting can cause recursive simplifications, which can invalidate
358 // our iterator. Use a WeakTrackingVH to hold onto it in case this
359 // happens.
360 Value *CurValue = &*CurInstIterator;
361 WeakTrackingVH IterHandle(CurValue);
362
363 f();
364
365 // If the iterator instruction was recursively deleted, start over at the
366 // start of the block.
367 if (IterHandle != CurValue) {
368 CurInstIterator = BB->begin();
369 SunkAddrs.clear();
370 }
371 }
372
373 // Get the DominatorTree, building if necessary.
374 DominatorTree &getDT(Function &F) {
375 if (!DT)
376 DT = std::make_unique<DominatorTree>(F);
377 return *DT;
378 }
379
380 void removeAllAssertingVHReferences(Value *V);
381 bool eliminateAssumptions(Function &F);
382 bool eliminateFallThrough(Function &F);
383 bool eliminateMostlyEmptyBlocks(Function &F);
384 BasicBlock *findDestBlockOfMergeableEmptyBlock(BasicBlock *BB);
385 bool canMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
386 void eliminateMostlyEmptyBlock(BasicBlock *BB);
387 bool isMergingEmptyBlockProfitable(BasicBlock *BB, BasicBlock *DestBB,
388 bool isPreheader);
389 bool makeBitReverse(Instruction &I);
390 bool optimizeBlock(BasicBlock &BB, bool &ModifiedDT);
391 bool optimizeInst(Instruction *I, bool &ModifiedDT);
392 bool optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
393 Type *AccessTy, unsigned AddrSpace);
394 bool optimizeGatherScatterInst(Instruction *MemoryInst, Value *Ptr);
395 bool optimizeInlineAsmInst(CallInst *CS);
396 bool optimizeCallInst(CallInst *CI, bool &ModifiedDT);
397 bool optimizeExt(Instruction *&I);
398 bool optimizeExtUses(Instruction *I);
399 bool optimizeLoadExt(LoadInst *Load);
400 bool optimizeShiftInst(BinaryOperator *BO);
401 bool optimizeFunnelShift(IntrinsicInst *Fsh);
402 bool optimizeSelectInst(SelectInst *SI);
403 bool optimizeShuffleVectorInst(ShuffleVectorInst *SVI);
404 bool optimizeSwitchInst(SwitchInst *SI);
405 bool optimizeExtractElementInst(Instruction *Inst);
406 bool dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT);
407 bool fixupDbgValue(Instruction *I);
408 bool placeDbgValues(Function &F);
409 bool placePseudoProbes(Function &F);
410 bool canFormExtLd(const SmallVectorImpl<Instruction *> &MovedExts,
411 LoadInst *&LI, Instruction *&Inst, bool HasPromoted);
412 bool tryToPromoteExts(TypePromotionTransaction &TPT,
413 const SmallVectorImpl<Instruction *> &Exts,
414 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
415 unsigned CreatedInstsCost = 0);
416 bool mergeSExts(Function &F);
417 bool splitLargeGEPOffsets();
418 bool optimizePhiType(PHINode *Inst, SmallPtrSetImpl<PHINode *> &Visited,
419 SmallPtrSetImpl<Instruction *> &DeletedInstrs);
420 bool optimizePhiTypes(Function &F);
421 bool performAddressTypePromotion(
422 Instruction *&Inst,
423 bool AllowPromotionWithoutCommonHeader,
424 bool HasPromoted, TypePromotionTransaction &TPT,
425 SmallVectorImpl<Instruction *> &SpeculativelyMovedExts);
426 bool splitBranchCondition(Function &F, bool &ModifiedDT);
427 bool simplifyOffsetableRelocate(GCStatepointInst &I);
428
429 bool tryToSinkFreeOperands(Instruction *I);
430 bool replaceMathCmpWithIntrinsic(BinaryOperator *BO, Value *Arg0,
431 Value *Arg1, CmpInst *Cmp,
432 Intrinsic::ID IID);
433 bool optimizeCmp(CmpInst *Cmp, bool &ModifiedDT);
434 bool combineToUSubWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
435 bool combineToUAddWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
436 void verifyBFIUpdates(Function &F);
437 };
438
439} // end anonymous namespace
440
441char CodeGenPrepare::ID = 0;
442
443INITIALIZE_PASS_BEGIN(CodeGenPrepare, DEBUG_TYPE,static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
444 "Optimize for code generation", false, false)static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
445INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)initializeLoopInfoWrapperPassPass(Registry);
446INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)initializeProfileSummaryInfoWrapperPassPass(Registry);
447INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
448INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)initializeTargetPassConfigPass(Registry);
449INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry);
450INITIALIZE_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)); }
451 "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)); }
452
453FunctionPass *llvm::createCodeGenPreparePass() { return new CodeGenPrepare(); }
454
455bool CodeGenPrepare::runOnFunction(Function &F) {
456 if (skipFunction(F))
457 return false;
458
459 DL = &F.getParent()->getDataLayout();
460
461 bool EverMadeChange = false;
462 // Clear per function information.
463 InsertedInsts.clear();
464 PromotedInsts.clear();
465
466 TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
467 SubtargetInfo = TM->getSubtargetImpl(F);
468 TLI = SubtargetInfo->getTargetLowering();
469 TRI = SubtargetInfo->getRegisterInfo();
470 TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
471 TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
472 LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
473 BPI.reset(new BranchProbabilityInfo(F, *LI));
474 BFI.reset(new BlockFrequencyInfo(F, *BPI, *LI));
475 PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
476 OptSize = F.hasOptSize();
477 if (ProfileGuidedSectionPrefix) {
478 // The hot attribute overwrites profile count based hotness while profile
479 // counts based hotness overwrite the cold attribute.
480 // This is a conservative behabvior.
481 if (F.hasFnAttribute(Attribute::Hot) ||
482 PSI->isFunctionHotInCallGraph(&F, *BFI))
483 F.setSectionPrefix("hot");
484 // If PSI shows this function is not hot, we will placed the function
485 // into unlikely section if (1) PSI shows this is a cold function, or
486 // (2) the function has a attribute of cold.
487 else if (PSI->isFunctionColdInCallGraph(&F, *BFI) ||
488 F.hasFnAttribute(Attribute::Cold))
489 F.setSectionPrefix("unlikely");
490 else if (ProfileUnknownInSpecialSection && PSI->hasPartialSampleProfile() &&
491 PSI->isFunctionHotnessUnknown(F))
492 F.setSectionPrefix("unknown");
493 }
494
495 /// This optimization identifies DIV instructions that can be
496 /// profitably bypassed and carried out with a shorter, faster divide.
497 if (!OptSize && !PSI->hasHugeWorkingSetSize() && TLI->isSlowDivBypassed()) {
498 const DenseMap<unsigned int, unsigned int> &BypassWidths =
499 TLI->getBypassSlowDivWidths();
500 BasicBlock* BB = &*F.begin();
501 while (BB != nullptr) {
502 // bypassSlowDivision may create new BBs, but we don't want to reapply the
503 // optimization to those blocks.
504 BasicBlock* Next = BB->getNextNode();
505 // F.hasOptSize is already checked in the outer if statement.
506 if (!llvm::shouldOptimizeForSize(BB, PSI, BFI.get()))
507 EverMadeChange |= bypassSlowDivision(BB, BypassWidths);
508 BB = Next;
509 }
510 }
511
512 // Get rid of @llvm.assume builtins before attempting to eliminate empty
513 // blocks, since there might be blocks that only contain @llvm.assume calls
514 // (plus arguments that we can get rid of).
515 EverMadeChange |= eliminateAssumptions(F);
516
517 // Eliminate blocks that contain only PHI nodes and an
518 // unconditional branch.
519 EverMadeChange |= eliminateMostlyEmptyBlocks(F);
520
521 bool ModifiedDT = false;
522 if (!DisableBranchOpts)
523 EverMadeChange |= splitBranchCondition(F, ModifiedDT);
524
525 // Split some critical edges where one of the sources is an indirect branch,
526 // to help generate sane code for PHIs involving such edges.
527 EverMadeChange |= SplitIndirectBrCriticalEdges(F);
528
529 bool MadeChange = true;
530 while (MadeChange) {
531 MadeChange = false;
532 DT.reset();
533 for (Function::iterator I = F.begin(); I != F.end(); ) {
534 BasicBlock *BB = &*I++;
535 bool ModifiedDTOnIteration = false;
536 MadeChange |= optimizeBlock(*BB, ModifiedDTOnIteration);
537
538 // Restart BB iteration if the dominator tree of the Function was changed
539 if (ModifiedDTOnIteration)
540 break;
541 }
542 if (EnableTypePromotionMerge && !ValToSExtendedUses.empty())
543 MadeChange |= mergeSExts(F);
544 if (!LargeOffsetGEPMap.empty())
545 MadeChange |= splitLargeGEPOffsets();
546 MadeChange |= optimizePhiTypes(F);
547
548 if (MadeChange)
549 eliminateFallThrough(F);
550
551 // Really free removed instructions during promotion.
552 for (Instruction *I : RemovedInsts)
553 I->deleteValue();
554
555 EverMadeChange |= MadeChange;
556 SeenChainsForSExt.clear();
557 ValToSExtendedUses.clear();
558 RemovedInsts.clear();
559 LargeOffsetGEPMap.clear();
560 LargeOffsetGEPID.clear();
561 }
562
563 NewGEPBases.clear();
564 SunkAddrs.clear();
565
566 if (!DisableBranchOpts) {
567 MadeChange = false;
568 // Use a set vector to get deterministic iteration order. The order the
569 // blocks are removed may affect whether or not PHI nodes in successors
570 // are removed.
571 SmallSetVector<BasicBlock*, 8> WorkList;
572 for (BasicBlock &BB : F) {
573 SmallVector<BasicBlock *, 2> Successors(successors(&BB));
574 MadeChange |= ConstantFoldTerminator(&BB, true);
575 if (!MadeChange) continue;
576
577 for (BasicBlock *Succ : Successors)
578 if (pred_empty(Succ))
579 WorkList.insert(Succ);
580 }
581
582 // Delete the dead blocks and any of their dead successors.
583 MadeChange |= !WorkList.empty();
584 while (!WorkList.empty()) {
585 BasicBlock *BB = WorkList.pop_back_val();
586 SmallVector<BasicBlock*, 2> Successors(successors(BB));
587
588 DeleteDeadBlock(BB);
589
590 for (BasicBlock *Succ : Successors)
591 if (pred_empty(Succ))
592 WorkList.insert(Succ);
593 }
594
595 // Merge pairs of basic blocks with unconditional branches, connected by
596 // a single edge.
597 if (EverMadeChange || MadeChange)
598 MadeChange |= eliminateFallThrough(F);
599
600 EverMadeChange |= MadeChange;
601 }
602
603 if (!DisableGCOpts) {
604 SmallVector<GCStatepointInst *, 2> Statepoints;
605 for (BasicBlock &BB : F)
606 for (Instruction &I : BB)
607 if (auto *SP = dyn_cast<GCStatepointInst>(&I))
608 Statepoints.push_back(SP);
609 for (auto &I : Statepoints)
610 EverMadeChange |= simplifyOffsetableRelocate(*I);
611 }
612
613 // Do this last to clean up use-before-def scenarios introduced by other
614 // preparatory transforms.
615 EverMadeChange |= placeDbgValues(F);
616 EverMadeChange |= placePseudoProbes(F);
617
618#ifndef NDEBUG1
619 if (VerifyBFIUpdates)
620 verifyBFIUpdates(F);
621#endif
622
623 return EverMadeChange;
624}
625
626bool CodeGenPrepare::eliminateAssumptions(Function &F) {
627 bool MadeChange = false;
628 for (BasicBlock &BB : F) {
629 CurInstIterator = BB.begin();
630 while (CurInstIterator != BB.end()) {
631 Instruction *I = &*(CurInstIterator++);
632 if (auto *Assume = dyn_cast<AssumeInst>(I)) {
633 MadeChange = true;
634 Value *Operand = Assume->getOperand(0);
635 Assume->eraseFromParent();
636
637 resetIteratorIfInvalidatedWhileCalling(&BB, [&]() {
638 RecursivelyDeleteTriviallyDeadInstructions(Operand, TLInfo, nullptr);
639 });
640 }
641 }
642 }
643 return MadeChange;
644}
645
646/// An instruction is about to be deleted, so remove all references to it in our
647/// GEP-tracking data strcutures.
648void CodeGenPrepare::removeAllAssertingVHReferences(Value *V) {
649 LargeOffsetGEPMap.erase(V);
650 NewGEPBases.erase(V);
651
652 auto GEP = dyn_cast<GetElementPtrInst>(V);
653 if (!GEP)
654 return;
655
656 LargeOffsetGEPID.erase(GEP);
657
658 auto VecI = LargeOffsetGEPMap.find(GEP->getPointerOperand());
659 if (VecI == LargeOffsetGEPMap.end())
660 return;
661
662 auto &GEPVector = VecI->second;
663 const auto &I =
664 llvm::find_if(GEPVector, [=](auto &Elt) { return Elt.first == GEP; });
665 if (I == GEPVector.end())
666 return;
667
668 GEPVector.erase(I);
669 if (GEPVector.empty())
670 LargeOffsetGEPMap.erase(VecI);
671}
672
673// Verify BFI has been updated correctly by recomputing BFI and comparing them.
674void LLVM_ATTRIBUTE_UNUSED__attribute__((__unused__)) CodeGenPrepare::verifyBFIUpdates(Function &F) {
675 DominatorTree NewDT(F);
676 LoopInfo NewLI(NewDT);
677 BranchProbabilityInfo NewBPI(F, NewLI, TLInfo);
678 BlockFrequencyInfo NewBFI(F, NewBPI, NewLI);
679 NewBFI.verifyMatch(*BFI);
680}
681
682/// Merge basic blocks which are connected by a single edge, where one of the
683/// basic blocks has a single successor pointing to the other basic block,
684/// which has a single predecessor.
685bool CodeGenPrepare::eliminateFallThrough(Function &F) {
686 bool Changed = false;
687 // Scan all of the blocks in the function, except for the entry block.
688 // Use a temporary array to avoid iterator being invalidated when
689 // deleting blocks.
690 SmallVector<WeakTrackingVH, 16> Blocks;
691 for (auto &Block : llvm::drop_begin(F))
692 Blocks.push_back(&Block);
693
694 SmallSet<WeakTrackingVH, 16> Preds;
695 for (auto &Block : Blocks) {
696 auto *BB = cast_or_null<BasicBlock>(Block);
697 if (!BB)
698 continue;
699 // If the destination block has a single pred, then this is a trivial
700 // edge, just collapse it.
701 BasicBlock *SinglePred = BB->getSinglePredecessor();
702
703 // Don't merge if BB's address is taken.
704 if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue;
705
706 BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
707 if (Term && !Term->isConditional()) {
708 Changed = true;
709 LLVM_DEBUG(dbgs() << "To merge:\n" << *BB << "\n\n\n")do { } while (false);
710
711 // Merge BB into SinglePred and delete it.
712 MergeBlockIntoPredecessor(BB);
713 Preds.insert(SinglePred);
714 }
715 }
716
717 // (Repeatedly) merging blocks into their predecessors can create redundant
718 // debug intrinsics.
719 for (auto &Pred : Preds)
720 if (auto *BB = cast_or_null<BasicBlock>(Pred))
721 RemoveRedundantDbgInstrs(BB);
722
723 return Changed;
724}
725
726/// Find a destination block from BB if BB is mergeable empty block.
727BasicBlock *CodeGenPrepare::findDestBlockOfMergeableEmptyBlock(BasicBlock *BB) {
728 // If this block doesn't end with an uncond branch, ignore it.
729 BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
730 if (!BI || !BI->isUnconditional())
731 return nullptr;
732
733 // If the instruction before the branch (skipping debug info) isn't a phi
734 // node, then other stuff is happening here.
735 BasicBlock::iterator BBI = BI->getIterator();
736 if (BBI != BB->begin()) {
737 --BBI;
738 while (isa<DbgInfoIntrinsic>(BBI)) {
739 if (BBI == BB->begin())
740 break;
741 --BBI;
742 }
743 if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI))
744 return nullptr;
745 }
746
747 // Do not break infinite loops.
748 BasicBlock *DestBB = BI->getSuccessor(0);
749 if (DestBB == BB)
750 return nullptr;
751
752 if (!canMergeBlocks(BB, DestBB))
753 DestBB = nullptr;
754
755 return DestBB;
756}
757
758/// Eliminate blocks that contain only PHI nodes, debug info directives, and an
759/// unconditional branch. Passes before isel (e.g. LSR/loopsimplify) often split
760/// edges in ways that are non-optimal for isel. Start by eliminating these
761/// blocks so we can split them the way we want them.
762bool CodeGenPrepare::eliminateMostlyEmptyBlocks(Function &F) {
763 SmallPtrSet<BasicBlock *, 16> Preheaders;
764 SmallVector<Loop *, 16> LoopList(LI->begin(), LI->end());
765 while (!LoopList.empty()) {
766 Loop *L = LoopList.pop_back_val();
767 llvm::append_range(LoopList, *L);
768 if (BasicBlock *Preheader = L->getLoopPreheader())
769 Preheaders.insert(Preheader);
770 }
771
772 bool MadeChange = false;
773 // Copy blocks into a temporary array to avoid iterator invalidation issues
774 // as we remove them.
775 // Note that this intentionally skips the entry block.
776 SmallVector<WeakTrackingVH, 16> Blocks;
777 for (auto &Block : llvm::drop_begin(F))
778 Blocks.push_back(&Block);
779
780 for (auto &Block : Blocks) {
781 BasicBlock *BB = cast_or_null<BasicBlock>(Block);
782 if (!BB)
783 continue;
784 BasicBlock *DestBB = findDestBlockOfMergeableEmptyBlock(BB);
785 if (!DestBB ||
786 !isMergingEmptyBlockProfitable(BB, DestBB, Preheaders.count(BB)))
787 continue;
788
789 eliminateMostlyEmptyBlock(BB);
790 MadeChange = true;
791 }
792 return MadeChange;
793}
794
795bool CodeGenPrepare::isMergingEmptyBlockProfitable(BasicBlock *BB,
796 BasicBlock *DestBB,
797 bool isPreheader) {
798 // Do not delete loop preheaders if doing so would create a critical edge.
799 // Loop preheaders can be good locations to spill registers. If the
800 // preheader is deleted and we create a critical edge, registers may be
801 // spilled in the loop body instead.
802 if (!DisablePreheaderProtect && isPreheader &&
803 !(BB->getSinglePredecessor() &&
804 BB->getSinglePredecessor()->getSingleSuccessor()))
805 return false;
806
807 // Skip merging if the block's successor is also a successor to any callbr
808 // that leads to this block.
809 // FIXME: Is this really needed? Is this a correctness issue?
810 for (BasicBlock *Pred : predecessors(BB)) {
811 if (auto *CBI = dyn_cast<CallBrInst>((Pred)->getTerminator()))
812 for (unsigned i = 0, e = CBI->getNumSuccessors(); i != e; ++i)
813 if (DestBB == CBI->getSuccessor(i))
814 return false;
815 }
816
817 // Try to skip merging if the unique predecessor of BB is terminated by a
818 // switch or indirect branch instruction, and BB is used as an incoming block
819 // of PHIs in DestBB. In such case, merging BB and DestBB would cause ISel to
820 // add COPY instructions in the predecessor of BB instead of BB (if it is not
821 // merged). Note that the critical edge created by merging such blocks wont be
822 // split in MachineSink because the jump table is not analyzable. By keeping
823 // such empty block (BB), ISel will place COPY instructions in BB, not in the
824 // predecessor of BB.
825 BasicBlock *Pred = BB->getUniquePredecessor();
826 if (!Pred ||
827 !(isa<SwitchInst>(Pred->getTerminator()) ||
828 isa<IndirectBrInst>(Pred->getTerminator())))
829 return true;
830
831 if (BB->getTerminator() != BB->getFirstNonPHIOrDbg())
832 return true;
833
834 // We use a simple cost heuristic which determine skipping merging is
835 // profitable if the cost of skipping merging is less than the cost of
836 // merging : Cost(skipping merging) < Cost(merging BB), where the
837 // Cost(skipping merging) is Freq(BB) * (Cost(Copy) + Cost(Branch)), and
838 // the Cost(merging BB) is Freq(Pred) * Cost(Copy).
839 // Assuming Cost(Copy) == Cost(Branch), we could simplify it to :
840 // Freq(Pred) / Freq(BB) > 2.
841 // Note that if there are multiple empty blocks sharing the same incoming
842 // value for the PHIs in the DestBB, we consider them together. In such
843 // case, Cost(merging BB) will be the sum of their frequencies.
844
845 if (!isa<PHINode>(DestBB->begin()))
846 return true;
847
848 SmallPtrSet<BasicBlock *, 16> SameIncomingValueBBs;
849
850 // Find all other incoming blocks from which incoming values of all PHIs in
851 // DestBB are the same as the ones from BB.
852 for (BasicBlock *DestBBPred : predecessors(DestBB)) {
853 if (DestBBPred == BB)
854 continue;
855
856 if (llvm::all_of(DestBB->phis(), [&](const PHINode &DestPN) {
857 return DestPN.getIncomingValueForBlock(BB) ==
858 DestPN.getIncomingValueForBlock(DestBBPred);
859 }))
860 SameIncomingValueBBs.insert(DestBBPred);
861 }
862
863 // See if all BB's incoming values are same as the value from Pred. In this
864 // case, no reason to skip merging because COPYs are expected to be place in
865 // Pred already.
866 if (SameIncomingValueBBs.count(Pred))
867 return true;
868
869 BlockFrequency PredFreq = BFI->getBlockFreq(Pred);
870 BlockFrequency BBFreq = BFI->getBlockFreq(BB);
871
872 for (auto *SameValueBB : SameIncomingValueBBs)
873 if (SameValueBB->getUniquePredecessor() == Pred &&
874 DestBB == findDestBlockOfMergeableEmptyBlock(SameValueBB))
875 BBFreq += BFI->getBlockFreq(SameValueBB);
876
877 return PredFreq.getFrequency() <=
878 BBFreq.getFrequency() * FreqRatioToSkipMerge;
879}
880
881/// Return true if we can merge BB into DestBB if there is a single
882/// unconditional branch between them, and BB contains no other non-phi
883/// instructions.
884bool CodeGenPrepare::canMergeBlocks(const BasicBlock *BB,
885 const BasicBlock *DestBB) const {
886 // We only want to eliminate blocks whose phi nodes are used by phi nodes in
887 // the successor. If there are more complex condition (e.g. preheaders),
888 // don't mess around with them.
889 for (const PHINode &PN : BB->phis()) {
890 for (const User *U : PN.users()) {
891 const Instruction *UI = cast<Instruction>(U);
892 if (UI->getParent() != DestBB || !isa<PHINode>(UI))
893 return false;
894 // If User is inside DestBB block and it is a PHINode then check
895 // incoming value. If incoming value is not from BB then this is
896 // a complex condition (e.g. preheaders) we want to avoid here.
897 if (UI->getParent() == DestBB) {
898 if (const PHINode *UPN = dyn_cast<PHINode>(UI))
899 for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
900 Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
901 if (Insn && Insn->getParent() == BB &&
902 Insn->getParent() != UPN->getIncomingBlock(I))
903 return false;
904 }
905 }
906 }
907 }
908
909 // If BB and DestBB contain any common predecessors, then the phi nodes in BB
910 // and DestBB may have conflicting incoming values for the block. If so, we
911 // can't merge the block.
912 const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
913 if (!DestBBPN) return true; // no conflict.
914
915 // Collect the preds of BB.
916 SmallPtrSet<const BasicBlock*, 16> BBPreds;
917 if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
918 // It is faster to get preds from a PHI than with pred_iterator.
919 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
920 BBPreds.insert(BBPN->getIncomingBlock(i));
921 } else {
922 BBPreds.insert(pred_begin(BB), pred_end(BB));
923 }
924
925 // Walk the preds of DestBB.
926 for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
927 BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
928 if (BBPreds.count(Pred)) { // Common predecessor?
929 for (const PHINode &PN : DestBB->phis()) {
930 const Value *V1 = PN.getIncomingValueForBlock(Pred);
931 const Value *V2 = PN.getIncomingValueForBlock(BB);
932
933 // If V2 is a phi node in BB, look up what the mapped value will be.
934 if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
935 if (V2PN->getParent() == BB)
936 V2 = V2PN->getIncomingValueForBlock(Pred);
937
938 // If there is a conflict, bail out.
939 if (V1 != V2) return false;
940 }
941 }
942 }
943
944 return true;
945}
946
947/// Eliminate a basic block that has only phi's and an unconditional branch in
948/// it.
949void CodeGenPrepare::eliminateMostlyEmptyBlock(BasicBlock *BB) {
950 BranchInst *BI = cast<BranchInst>(BB->getTerminator());
951 BasicBlock *DestBB = BI->getSuccessor(0);
952
953 LLVM_DEBUG(dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"do { } while (false)
954 << *BB << *DestBB)do { } while (false);
955
956 // If the destination block has a single pred, then this is a trivial edge,
957 // just collapse it.
958 if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
959 if (SinglePred != DestBB) {
960 assert(SinglePred == BB &&(static_cast<void> (0))
961 "Single predecessor not the same as predecessor")(static_cast<void> (0));
962 // Merge DestBB into SinglePred/BB and delete it.
963 MergeBlockIntoPredecessor(DestBB);
964 // Note: BB(=SinglePred) will not be deleted on this path.
965 // DestBB(=its single successor) is the one that was deleted.
966 LLVM_DEBUG(dbgs() << "AFTER:\n" << *SinglePred << "\n\n\n")do { } while (false);
967 return;
968 }
969 }
970
971 // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
972 // to handle the new incoming edges it is about to have.
973 for (PHINode &PN : DestBB->phis()) {
974 // Remove the incoming value for BB, and remember it.
975 Value *InVal = PN.removeIncomingValue(BB, false);
976
977 // Two options: either the InVal is a phi node defined in BB or it is some
978 // value that dominates BB.
979 PHINode *InValPhi = dyn_cast<PHINode>(InVal);
980 if (InValPhi && InValPhi->getParent() == BB) {
981 // Add all of the input values of the input PHI as inputs of this phi.
982 for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
983 PN.addIncoming(InValPhi->getIncomingValue(i),
984 InValPhi->getIncomingBlock(i));
985 } else {
986 // Otherwise, add one instance of the dominating value for each edge that
987 // we will be adding.
988 if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
989 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
990 PN.addIncoming(InVal, BBPN->getIncomingBlock(i));
991 } else {
992 for (BasicBlock *Pred : predecessors(BB))
993 PN.addIncoming(InVal, Pred);
994 }
995 }
996 }
997
998 // The PHIs are now updated, change everything that refers to BB to use
999 // DestBB and remove BB.
1000 BB->replaceAllUsesWith(DestBB);
1001 BB->eraseFromParent();
1002 ++NumBlocksElim;
1003
1004 LLVM_DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n")do { } while (false);
1005}
1006
1007// Computes a map of base pointer relocation instructions to corresponding
1008// derived pointer relocation instructions given a vector of all relocate calls
1009static void computeBaseDerivedRelocateMap(
1010 const SmallVectorImpl<GCRelocateInst *> &AllRelocateCalls,
1011 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>>
1012 &RelocateInstMap) {
1013 // Collect information in two maps: one primarily for locating the base object
1014 // while filling the second map; the second map is the final structure holding
1015 // a mapping between Base and corresponding Derived relocate calls
1016 DenseMap<std::pair<unsigned, unsigned>, GCRelocateInst *> RelocateIdxMap;
1017 for (auto *ThisRelocate : AllRelocateCalls) {
1018 auto K = std::make_pair(ThisRelocate->getBasePtrIndex(),
1019 ThisRelocate->getDerivedPtrIndex());
1020 RelocateIdxMap.insert(std::make_pair(K, ThisRelocate));
1021 }
1022 for (auto &Item : RelocateIdxMap) {
1023 std::pair<unsigned, unsigned> Key = Item.first;
1024 if (Key.first == Key.second)
1025 // Base relocation: nothing to insert
1026 continue;
1027
1028 GCRelocateInst *I = Item.second;
1029 auto BaseKey = std::make_pair(Key.first, Key.first);
1030
1031 // We're iterating over RelocateIdxMap so we cannot modify it.
1032 auto MaybeBase = RelocateIdxMap.find(BaseKey);
1033 if (MaybeBase == RelocateIdxMap.end())
1034 // TODO: We might want to insert a new base object relocate and gep off
1035 // that, if there are enough derived object relocates.
1036 continue;
1037
1038 RelocateInstMap[MaybeBase->second].push_back(I);
1039 }
1040}
1041
1042// Accepts a GEP and extracts the operands into a vector provided they're all
1043// small integer constants
1044static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
1045 SmallVectorImpl<Value *> &OffsetV) {
1046 for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
18
Assuming the condition is false
19
Loop condition is false. Execution continues on line 1053
1047 // Only accept small constant integer operands
1048 auto *Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
1049 if (!Op || Op->getZExtValue() > 20)
1050 return false;
1051 }
1052
1053 for (unsigned i = 1; i < GEP->getNumOperands(); i++)
20
Loop condition is false. Execution continues on line 1055
1054 OffsetV.push_back(GEP->getOperand(i));
1055 return true;
21
Returning the value 1, which participates in a condition later
1056}
1057
1058// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
1059// replace, computes a replacement, and affects it.
1060static bool
1061simplifyRelocatesOffABase(GCRelocateInst *RelocatedBase,
1062 const SmallVectorImpl<GCRelocateInst *> &Targets) {
1063 bool MadeChange = false;
1064 // We must ensure the relocation of derived pointer is defined after
1065 // relocation of base pointer. If we find a relocation corresponding to base
1066 // defined earlier than relocation of base then we move relocation of base
1067 // right before found relocation. We consider only relocation in the same
1068 // basic block as relocation of base. Relocations from other basic block will
1069 // be skipped by optimization and we do not care about them.
1070 for (auto R = RelocatedBase->getParent()->getFirstInsertionPt();
7
Loop condition is false. Execution continues on line 1079
1071 &*R != RelocatedBase; ++R)
6
Assuming the condition is false
1072 if (auto *RI = dyn_cast<GCRelocateInst>(R))
1073 if (RI->getStatepoint() == RelocatedBase->getStatepoint())
1074 if (RI->getBasePtrIndex() == RelocatedBase->getBasePtrIndex()) {
1075 RelocatedBase->moveBefore(RI);
1076 break;
1077 }
1078
1079 for (GCRelocateInst *ToReplace : Targets) {
8
Assuming '__begin1' is not equal to '__end1'
1080 assert(ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() &&(static_cast<void> (0))
1081 "Not relocating a derived object of the original base object")(static_cast<void> (0));
1082 if (ToReplace->getBasePtrIndex() == ToReplace->getDerivedPtrIndex()) {
9
Assuming the condition is false
10
Taking false branch
1083 // A duplicate relocate call. TODO: coalesce duplicates.
1084 continue;
1085 }
1086
1087 if (RelocatedBase->getParent() != ToReplace->getParent()) {
11
Assuming the condition is false
12
Taking false branch
1088 // Base and derived relocates are in different basic blocks.
1089 // In this case transform is only valid when base dominates derived
1090 // relocate. However it would be too expensive to check dominance
1091 // for each such relocate, so we skip the whole transformation.
1092 continue;
1093 }
1094
1095 Value *Base = ToReplace->getBasePtr();
13
'Base' initialized here
1096 auto *Derived = dyn_cast<GetElementPtrInst>(ToReplace->getDerivedPtr());
14
Assuming the object is a 'GetElementPtrInst'
1097 if (!Derived
14.1
'Derived' is non-null
|| Derived->getPointerOperand() != Base)
15
Assuming pointer value is null
16
Taking false branch
1098 continue;
1099
1100 SmallVector<Value *, 2> OffsetV;
1101 if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
17
Calling 'getGEPSmallConstantIntOffsetV'
22
Returning from 'getGEPSmallConstantIntOffsetV'
23
Taking false branch
1102 continue;
1103
1104 // Create a Builder and replace the target callsite with a gep
1105 assert(RelocatedBase->getNextNode() &&(static_cast<void> (0))
1106 "Should always have one since it's not a terminator")(static_cast<void> (0));
1107
1108 // Insert after RelocatedBase
1109 IRBuilder<> Builder(RelocatedBase->getNextNode());
1110 Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
1111
1112 // If gc_relocate does not match the actual type, cast it to the right type.
1113 // In theory, there must be a bitcast after gc_relocate if the type does not
1114 // match, and we should reuse it to get the derived pointer. But it could be
1115 // cases like this:
1116 // bb1:
1117 // ...
1118 // %g1 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
1119 // br label %merge
1120 //
1121 // bb2:
1122 // ...
1123 // %g2 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
1124 // br label %merge
1125 //
1126 // merge:
1127 // %p1 = phi i8 addrspace(1)* [ %g1, %bb1 ], [ %g2, %bb2 ]
1128 // %cast = bitcast i8 addrspace(1)* %p1 in to i32 addrspace(1)*
1129 //
1130 // In this case, we can not find the bitcast any more. So we insert a new bitcast
1131 // no matter there is already one or not. In this way, we can handle all cases, and
1132 // the extra bitcast should be optimized away in later passes.
1133 Value *ActualRelocatedBase = RelocatedBase;
1134 if (RelocatedBase->getType() != Base->getType()) {
24
Called C++ object pointer is null
1135 ActualRelocatedBase =
1136 Builder.CreateBitCast(RelocatedBase, Base->getType());
1137 }
1138 Value *Replacement = Builder.CreateGEP(
1139 Derived->getSourceElementType(), ActualRelocatedBase, makeArrayRef(OffsetV));
1140 Replacement->takeName(ToReplace);
1141 // If the newly generated derived pointer's type does not match the original derived
1142 // pointer's type, cast the new derived pointer to match it. Same reasoning as above.
1143 Value *ActualReplacement = Replacement;
1144 if (Replacement->getType() != ToReplace->getType()) {
1145 ActualReplacement =
1146 Builder.CreateBitCast(Replacement, ToReplace->getType());
1147 }
1148 ToReplace->replaceAllUsesWith(ActualReplacement);
1149 ToReplace->eraseFromParent();
1150
1151 MadeChange = true;
1152 }
1153 return MadeChange;
1154}
1155
1156// Turns this:
1157//
1158// %base = ...
1159// %ptr = gep %base + 15
1160// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1161// %base' = relocate(%tok, i32 4, i32 4)
1162// %ptr' = relocate(%tok, i32 4, i32 5)
1163// %val = load %ptr'
1164//
1165// into this:
1166//
1167// %base = ...
1168// %ptr = gep %base + 15
1169// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1170// %base' = gc.relocate(%tok, i32 4, i32 4)
1171// %ptr' = gep %base' + 15
1172// %val = load %ptr'
1173bool CodeGenPrepare::simplifyOffsetableRelocate(GCStatepointInst &I) {
1174 bool MadeChange = false;
1175 SmallVector<GCRelocateInst *, 2> AllRelocateCalls;
1176 for (auto *U : I.users())
1177 if (GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U))
1178 // Collect all the relocate calls associated with a statepoint
1179 AllRelocateCalls.push_back(Relocate);
1180
1181 // We need at least one base pointer relocation + one derived pointer
1182 // relocation to mangle
1183 if (AllRelocateCalls.size() < 2)
1
Assuming the condition is false
2
Taking false branch
1184 return false;
1185
1186 // RelocateInstMap is a mapping from the base relocate instruction to the
1187 // corresponding derived relocate instructions
1188 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>> RelocateInstMap;
1189 computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
1190 if (RelocateInstMap.empty())
3
Assuming the condition is false
4
Taking false branch
1191 return false;
1192
1193 for (auto &Item : RelocateInstMap)
1194 // Item.first is the RelocatedBase to offset against
1195 // Item.second is the vector of Targets to replace
1196 MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
5
Calling 'simplifyRelocatesOffABase'
1197 return MadeChange;
1198}
1199
1200/// Sink the specified cast instruction into its user blocks.
1201static bool SinkCast(CastInst *CI) {
1202 BasicBlock *DefBB = CI->getParent();
1203
1204 /// InsertedCasts - Only insert a cast in each block once.
1205 DenseMap<BasicBlock*, CastInst*> InsertedCasts;
1206
1207 bool MadeChange = false;
1208 for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
1209 UI != E; ) {
1210 Use &TheUse = UI.getUse();
1211 Instruction *User = cast<Instruction>(*UI);
1212
1213 // Figure out which BB this cast is used in. For PHI's this is the
1214 // appropriate predecessor block.
1215 BasicBlock *UserBB = User->getParent();
1216 if (PHINode *PN = dyn_cast<PHINode>(User)) {
1217 UserBB = PN->getIncomingBlock(TheUse);
1218 }
1219
1220 // Preincrement use iterator so we don't invalidate it.
1221 ++UI;
1222
1223 // The first insertion point of a block containing an EH pad is after the
1224 // pad. If the pad is the user, we cannot sink the cast past the pad.
1225 if (User->isEHPad())
1226 continue;
1227
1228 // If the block selected to receive the cast is an EH pad that does not
1229 // allow non-PHI instructions before the terminator, we can't sink the
1230 // cast.
1231 if (UserBB->getTerminator()->isEHPad())
1232 continue;
1233
1234 // If this user is in the same block as the cast, don't change the cast.
1235 if (UserBB == DefBB) continue;
1236
1237 // If we have already inserted a cast into this block, use it.
1238 CastInst *&InsertedCast = InsertedCasts[UserBB];
1239
1240 if (!InsertedCast) {
1241 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1242 assert(InsertPt != UserBB->end())(static_cast<void> (0));
1243 InsertedCast = CastInst::Create(CI->getOpcode(), CI->getOperand(0),
1244 CI->getType(), "", &*InsertPt);
1245 InsertedCast->setDebugLoc(CI->getDebugLoc());
1246 }
1247
1248 // Replace a use of the cast with a use of the new cast.
1249 TheUse = InsertedCast;
1250 MadeChange = true;
1251 ++NumCastUses;
1252 }
1253
1254 // If we removed all uses, nuke the cast.
1255 if (CI->use_empty()) {
1256 salvageDebugInfo(*CI);
1257 CI->eraseFromParent();
1258 MadeChange = true;
1259 }
1260
1261 return MadeChange;
1262}
1263
1264/// If the specified cast instruction is a noop copy (e.g. it's casting from
1265/// one pointer type to another, i32->i8 on PPC), sink it into user blocks to
1266/// reduce the number of virtual registers that must be created and coalesced.
1267///
1268/// Return true if any changes are made.
1269static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI,
1270 const DataLayout &DL) {
1271 // Sink only "cheap" (or nop) address-space casts. This is a weaker condition
1272 // than sinking only nop casts, but is helpful on some platforms.
1273 if (auto *ASC = dyn_cast<AddrSpaceCastInst>(CI)) {
1274 if (!TLI.isFreeAddrSpaceCast(ASC->getSrcAddressSpace(),
1275 ASC->getDestAddressSpace()))
1276 return false;
1277 }
1278
1279 // If this is a noop copy,
1280 EVT SrcVT = TLI.getValueType(DL, CI->getOperand(0)->getType());
1281 EVT DstVT = TLI.getValueType(DL, CI->getType());
1282
1283 // This is an fp<->int conversion?
1284 if (SrcVT.isInteger() != DstVT.isInteger())
1285 return false;
1286
1287 // If this is an extension, it will be a zero or sign extension, which
1288 // isn't a noop.
1289 if (SrcVT.bitsLT(DstVT)) return false;
1290
1291 // If these values will be promoted, find out what they will be promoted
1292 // to. This helps us consider truncates on PPC as noop copies when they
1293 // are.
1294 if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
1295 TargetLowering::TypePromoteInteger)
1296 SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
1297 if (TLI.getTypeAction(CI->getContext(), DstVT) ==
1298 TargetLowering::TypePromoteInteger)
1299 DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
1300
1301 // If, after promotion, these are the same types, this is a noop copy.
1302 if (SrcVT != DstVT)
1303 return false;
1304
1305 return SinkCast(CI);
1306}
1307
1308// Match a simple increment by constant operation. Note that if a sub is
1309// matched, the step is negated (as if the step had been canonicalized to
1310// an add, even though we leave the instruction alone.)
1311bool matchIncrement(const Instruction* IVInc, Instruction *&LHS,
1312 Constant *&Step) {
1313 if (match(IVInc, m_Add(m_Instruction(LHS), m_Constant(Step))) ||
1314 match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::uadd_with_overflow>(
1315 m_Instruction(LHS), m_Constant(Step)))))
1316 return true;
1317 if (match(IVInc, m_Sub(m_Instruction(LHS), m_Constant(Step))) ||
1318 match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::usub_with_overflow>(
1319 m_Instruction(LHS), m_Constant(Step))))) {
1320 Step = ConstantExpr::getNeg(Step);
1321 return true;
1322 }
1323 return false;
1324}
1325
1326/// If given \p PN is an inductive variable with value IVInc coming from the
1327/// backedge, and on each iteration it gets increased by Step, return pair
1328/// <IVInc, Step>. Otherwise, return None.
1329static Optional<std::pair<Instruction *, Constant *> >
1330getIVIncrement(const PHINode *PN, const LoopInfo *LI) {
1331 const Loop *L = LI->getLoopFor(PN->getParent());
1332 if (!L || L->getHeader() != PN->getParent() || !L->getLoopLatch())
1333 return None;
1334 auto *IVInc =
1335 dyn_cast<Instruction>(PN->getIncomingValueForBlock(L->getLoopLatch()));
1336 if (!IVInc || LI->getLoopFor(IVInc->getParent()) != L)
1337 return None;
1338 Instruction *LHS = nullptr;
1339 Constant *Step = nullptr;
1340 if (matchIncrement(IVInc, LHS, Step) && LHS == PN)
1341 return std::make_pair(IVInc, Step);
1342 return None;
1343}
1344
1345static bool isIVIncrement(const Value *V, const LoopInfo *LI) {
1346 auto *I = dyn_cast<Instruction>(V);
1347 if (!I)
1348 return false;
1349 Instruction *LHS = nullptr;
1350 Constant *Step = nullptr;
1351 if (!matchIncrement(I, LHS, Step))
1352 return false;
1353 if (auto *PN = dyn_cast<PHINode>(LHS))
1354 if (auto IVInc = getIVIncrement(PN, LI))
1355 return IVInc->first == I;
1356 return false;
1357}
1358
1359bool CodeGenPrepare::replaceMathCmpWithIntrinsic(BinaryOperator *BO,
1360 Value *Arg0, Value *Arg1,
1361 CmpInst *Cmp,
1362 Intrinsic::ID IID) {
1363 auto IsReplacableIVIncrement = [this, &Cmp](BinaryOperator *BO) {
1364 if (!isIVIncrement(BO, LI))
1365 return false;
1366 const Loop *L = LI->getLoopFor(BO->getParent());
1367 assert(L && "L should not be null after isIVIncrement()")(static_cast<void> (0));
1368 // Do not risk on moving increment into a child loop.
1369 if (LI->getLoopFor(Cmp->getParent()) != L)
1370 return false;
1371
1372 // Finally, we need to ensure that the insert point will dominate all
1373 // existing uses of the increment.
1374
1375 auto &DT = getDT(*BO->getParent()->getParent());
1376 if (DT.dominates(Cmp->getParent(), BO->getParent()))
1377 // If we're moving up the dom tree, all uses are trivially dominated.
1378 // (This is the common case for code produced by LSR.)
1379 return true;
1380
1381 // Otherwise, special case the single use in the phi recurrence.
1382 return BO->hasOneUse() && DT.dominates(Cmp->getParent(), L->getLoopLatch());
1383 };
1384 if (BO->getParent() != Cmp->getParent() && !IsReplacableIVIncrement(BO)) {
1385 // We used to use a dominator tree here to allow multi-block optimization.
1386 // But that was problematic because:
1387 // 1. It could cause a perf regression by hoisting the math op into the
1388 // critical path.
1389 // 2. It could cause a perf regression by creating a value that was live
1390 // across multiple blocks and increasing register pressure.
1391 // 3. Use of a dominator tree could cause large compile-time regression.
1392 // This is because we recompute the DT on every change in the main CGP
1393 // run-loop. The recomputing is probably unnecessary in many cases, so if
1394 // that was fixed, using a DT here would be ok.
1395 //
1396 // There is one important particular case we still want to handle: if BO is
1397 // the IV increment. Important properties that make it profitable:
1398 // - We can speculate IV increment anywhere in the loop (as long as the
1399 // indvar Phi is its only user);
1400 // - Upon computing Cmp, we effectively compute something equivalent to the
1401 // IV increment (despite it loops differently in the IR). So moving it up
1402 // to the cmp point does not really increase register pressure.
1403 return false;
1404 }
1405
1406 // We allow matching the canonical IR (add X, C) back to (usubo X, -C).
1407 if (BO->getOpcode() == Instruction::Add &&
1408 IID == Intrinsic::usub_with_overflow) {
1409 assert(isa<Constant>(Arg1) && "Unexpected input for usubo")(static_cast<void> (0));
1410 Arg1 = ConstantExpr::getNeg(cast<Constant>(Arg1));
1411 }
1412
1413 // Insert at the first instruction of the pair.
1414 Instruction *InsertPt = nullptr;
1415 for (Instruction &Iter : *Cmp->getParent()) {
1416 // If BO is an XOR, it is not guaranteed that it comes after both inputs to
1417 // the overflow intrinsic are defined.
1418 if ((BO->getOpcode() != Instruction::Xor && &Iter == BO) || &Iter == Cmp) {
1419 InsertPt = &Iter;
1420 break;
1421 }
1422 }
1423 assert(InsertPt != nullptr && "Parent block did not contain cmp or binop")(static_cast<void> (0));
1424
1425 IRBuilder<> Builder(InsertPt);
1426 Value *MathOV = Builder.CreateBinaryIntrinsic(IID, Arg0, Arg1);
1427 if (BO->getOpcode() != Instruction::Xor) {
1428 Value *Math = Builder.CreateExtractValue(MathOV, 0, "math");
1429 BO->replaceAllUsesWith(Math);
1430 } else
1431 assert(BO->hasOneUse() &&(static_cast<void> (0))
1432 "Patterns with XOr should use the BO only in the compare")(static_cast<void> (0));
1433 Value *OV = Builder.CreateExtractValue(MathOV, 1, "ov");
1434 Cmp->replaceAllUsesWith(OV);
1435 Cmp->eraseFromParent();
1436 BO->eraseFromParent();
1437 return true;
1438}
1439
1440/// Match special-case patterns that check for unsigned add overflow.
1441static bool matchUAddWithOverflowConstantEdgeCases(CmpInst *Cmp,
1442 BinaryOperator *&Add) {
1443 // Add = add A, 1; Cmp = icmp eq A,-1 (overflow if A is max val)
1444 // Add = add A,-1; Cmp = icmp ne A, 0 (overflow if A is non-zero)
1445 Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
1446
1447 // We are not expecting non-canonical/degenerate code. Just bail out.
1448 if (isa<Constant>(A))
1449 return false;
1450
1451 ICmpInst::Predicate Pred = Cmp->getPredicate();
1452 if (Pred == ICmpInst::ICMP_EQ && match(B, m_AllOnes()))
1453 B = ConstantInt::get(B->getType(), 1);
1454 else if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt()))
1455 B = ConstantInt::get(B->getType(), -1);
1456 else
1457 return false;
1458
1459 // Check the users of the variable operand of the compare looking for an add
1460 // with the adjusted constant.
1461 for (User *U : A->users()) {
1462 if (match(U, m_Add(m_Specific(A), m_Specific(B)))) {
1463 Add = cast<BinaryOperator>(U);
1464 return true;
1465 }
1466 }
1467 return false;
1468}
1469
1470/// Try to combine the compare into a call to the llvm.uadd.with.overflow
1471/// intrinsic. Return true if any changes were made.
1472bool CodeGenPrepare::combineToUAddWithOverflow(CmpInst *Cmp,
1473 bool &ModifiedDT) {
1474 Value *A, *B;
1475 BinaryOperator *Add;
1476 if (!match(Cmp, m_UAddWithOverflow(m_Value(A), m_Value(B), m_BinOp(Add)))) {
1477 if (!matchUAddWithOverflowConstantEdgeCases(Cmp, Add))
1478 return false;
1479 // Set A and B in case we match matchUAddWithOverflowConstantEdgeCases.
1480 A = Add->getOperand(0);
1481 B = Add->getOperand(1);
1482 }
1483
1484 if (!TLI->shouldFormOverflowOp(ISD::UADDO,
1485 TLI->getValueType(*DL, Add->getType()),
1486 Add->hasNUsesOrMore(2)))
1487 return false;
1488
1489 // We don't want to move around uses of condition values this late, so we
1490 // check if it is legal to create the call to the intrinsic in the basic
1491 // block containing the icmp.
1492 if (Add->getParent() != Cmp->getParent() && !Add->hasOneUse())
1493 return false;
1494
1495 if (!replaceMathCmpWithIntrinsic(Add, A, B, Cmp,
1496 Intrinsic::uadd_with_overflow))
1497 return false;
1498
1499 // Reset callers - do not crash by iterating over a dead instruction.
1500 ModifiedDT = true;
1501 return true;
1502}
1503
1504bool CodeGenPrepare::combineToUSubWithOverflow(CmpInst *Cmp,
1505 bool &ModifiedDT) {
1506 // We are not expecting non-canonical/degenerate code. Just bail out.
1507 Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
1508 if (isa<Constant>(A) && isa<Constant>(B))
1509 return false;
1510
1511 // Convert (A u> B) to (A u< B) to simplify pattern matching.
1512 ICmpInst::Predicate Pred = Cmp->getPredicate();
1513 if (Pred == ICmpInst::ICMP_UGT) {
1514 std::swap(A, B);
1515 Pred = ICmpInst::ICMP_ULT;
1516 }
1517 // Convert special-case: (A == 0) is the same as (A u< 1).
1518 if (Pred == ICmpInst::ICMP_EQ && match(B, m_ZeroInt())) {
1519 B = ConstantInt::get(B->getType(), 1);
1520 Pred = ICmpInst::ICMP_ULT;
1521 }
1522 // Convert special-case: (A != 0) is the same as (0 u< A).
1523 if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt())) {
1524 std::swap(A, B);
1525 Pred = ICmpInst::ICMP_ULT;
1526 }
1527 if (Pred != ICmpInst::ICMP_ULT)
1528 return false;
1529
1530 // Walk the users of a variable operand of a compare looking for a subtract or
1531 // add with that same operand. Also match the 2nd operand of the compare to
1532 // the add/sub, but that may be a negated constant operand of an add.
1533 Value *CmpVariableOperand = isa<Constant>(A) ? B : A;
1534 BinaryOperator *Sub = nullptr;
1535 for (User *U : CmpVariableOperand->users()) {
1536 // A - B, A u< B --> usubo(A, B)
1537 if (match(U, m_Sub(m_Specific(A), m_Specific(B)))) {
1538 Sub = cast<BinaryOperator>(U);
1539 break;
1540 }
1541
1542 // A + (-C), A u< C (canonicalized form of (sub A, C))
1543 const APInt *CmpC, *AddC;
1544 if (match(U, m_Add(m_Specific(A), m_APInt(AddC))) &&
1545 match(B, m_APInt(CmpC)) && *AddC == -(*CmpC)) {
1546 Sub = cast<BinaryOperator>(U);
1547 break;
1548 }
1549 }
1550 if (!Sub)
1551 return false;
1552
1553 if (!TLI->shouldFormOverflowOp(ISD::USUBO,
1554 TLI->getValueType(*DL, Sub->getType()),
1555 Sub->hasNUsesOrMore(2)))
1556 return false;
1557
1558 if (!replaceMathCmpWithIntrinsic(Sub, Sub->getOperand(0), Sub->getOperand(1),
1559 Cmp, Intrinsic::usub_with_overflow))
1560 return false;
1561
1562 // Reset callers - do not crash by iterating over a dead instruction.
1563 ModifiedDT = true;
1564 return true;
1565}
1566
1567/// Sink the given CmpInst into user blocks to reduce the number of virtual
1568/// registers that must be created and coalesced. This is a clear win except on
1569/// targets with multiple condition code registers (PowerPC), where it might
1570/// lose; some adjustment may be wanted there.
1571///
1572/// Return true if any changes are made.
1573static bool sinkCmpExpression(CmpInst *Cmp, const TargetLowering &TLI) {
1574 if (TLI.hasMultipleConditionRegisters())
1575 return false;
1576
1577 // Avoid sinking soft-FP comparisons, since this can move them into a loop.
1578 if (TLI.useSoftFloat() && isa<FCmpInst>(Cmp))
1579 return false;
1580
1581 // Only insert a cmp in each block once.
1582 DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
1583
1584 bool MadeChange = false;
1585 for (Value::user_iterator UI = Cmp->user_begin(), E = Cmp->user_end();
1586 UI != E; ) {
1587 Use &TheUse = UI.getUse();
1588 Instruction *User = cast<Instruction>(*UI);
1589
1590 // Preincrement use iterator so we don't invalidate it.
1591 ++UI;
1592
1593 // Don't bother for PHI nodes.
1594 if (isa<PHINode>(User))
1595 continue;
1596
1597 // Figure out which BB this cmp is used in.
1598 BasicBlock *UserBB = User->getParent();
1599 BasicBlock *DefBB = Cmp->getParent();
1600
1601 // If this user is in the same block as the cmp, don't change the cmp.
1602 if (UserBB == DefBB) continue;
1603
1604 // If we have already inserted a cmp into this block, use it.
1605 CmpInst *&InsertedCmp = InsertedCmps[UserBB];
1606
1607 if (!InsertedCmp) {
1608 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1609 assert(InsertPt != UserBB->end())(static_cast<void> (0));
1610 InsertedCmp =
1611 CmpInst::Create(Cmp->getOpcode(), Cmp->getPredicate(),
1612 Cmp->getOperand(0), Cmp->getOperand(1), "",
1613 &*InsertPt);
1614 // Propagate the debug info.
1615 InsertedCmp->setDebugLoc(Cmp->getDebugLoc());
1616 }
1617
1618 // Replace a use of the cmp with a use of the new cmp.
1619 TheUse = InsertedCmp;
1620 MadeChange = true;
1621 ++NumCmpUses;
1622 }
1623
1624 // If we removed all uses, nuke the cmp.
1625 if (Cmp->use_empty()) {
1626 Cmp->eraseFromParent();
1627 MadeChange = true;
1628 }
1629
1630 return MadeChange;
1631}
1632
1633/// For pattern like:
1634///
1635/// DomCond = icmp sgt/slt CmpOp0, CmpOp1 (might not be in DomBB)
1636/// ...
1637/// DomBB:
1638/// ...
1639/// br DomCond, TrueBB, CmpBB
1640/// CmpBB: (with DomBB being the single predecessor)
1641/// ...
1642/// Cmp = icmp eq CmpOp0, CmpOp1
1643/// ...
1644///
1645/// It would use two comparison on targets that lowering of icmp sgt/slt is
1646/// different from lowering of icmp eq (PowerPC). This function try to convert
1647/// 'Cmp = icmp eq CmpOp0, CmpOp1' to ' Cmp = icmp slt/sgt CmpOp0, CmpOp1'.
1648/// After that, DomCond and Cmp can use the same comparison so reduce one
1649/// comparison.
1650///
1651/// Return true if any changes are made.
1652static bool foldICmpWithDominatingICmp(CmpInst *Cmp,
1653 const TargetLowering &TLI) {
1654 if (!EnableICMP_EQToICMP_ST && TLI.isEqualityCmpFoldedWithSignedCmp())
1655 return false;
1656
1657 ICmpInst::Predicate Pred = Cmp->getPredicate();
1658 if (Pred != ICmpInst::ICMP_EQ)
1659 return false;
1660
1661 // If icmp eq has users other than BranchInst and SelectInst, converting it to
1662 // icmp slt/sgt would introduce more redundant LLVM IR.
1663 for (User *U : Cmp->users()) {
1664 if (isa<BranchInst>(U))
1665 continue;
1666 if (isa<SelectInst>(U) && cast<SelectInst>(U)->getCondition() == Cmp)
1667 continue;
1668 return false;
1669 }
1670
1671 // This is a cheap/incomplete check for dominance - just match a single
1672 // predecessor with a conditional branch.
1673 BasicBlock *CmpBB = Cmp->getParent();
1674 BasicBlock *DomBB = CmpBB->getSinglePredecessor();
1675 if (!DomBB)
1676 return false;
1677
1678 // We want to ensure that the only way control gets to the comparison of
1679 // interest is that a less/greater than comparison on the same operands is
1680 // false.
1681 Value *DomCond;
1682 BasicBlock *TrueBB, *FalseBB;
1683 if (!match(DomBB->getTerminator(), m_Br(m_Value(DomCond), TrueBB, FalseBB)))
1684 return false;
1685 if (CmpBB != FalseBB)
1686 return false;
1687
1688 Value *CmpOp0 = Cmp->getOperand(0), *CmpOp1 = Cmp->getOperand(1);
1689 ICmpInst::Predicate DomPred;
1690 if (!match(DomCond, m_ICmp(DomPred, m_Specific(CmpOp0), m_Specific(CmpOp1))))
1691 return false;
1692 if (DomPred != ICmpInst::ICMP_SGT && DomPred != ICmpInst::ICMP_SLT)
1693 return false;
1694
1695 // Convert the equality comparison to the opposite of the dominating
1696 // comparison and swap the direction for all branch/select users.
1697 // We have conceptually converted:
1698 // Res = (a < b) ? <LT_RES> : (a == b) ? <EQ_RES> : <GT_RES>;
1699 // to
1700 // Res = (a < b) ? <LT_RES> : (a > b) ? <GT_RES> : <EQ_RES>;
1701 // And similarly for branches.
1702 for (User *U : Cmp->users()) {
1703 if (auto *BI = dyn_cast<BranchInst>(U)) {
1704 assert(BI->isConditional() && "Must be conditional")(static_cast<void> (0));
1705 BI->swapSuccessors();
1706 continue;
1707 }
1708 if (auto *SI = dyn_cast<SelectInst>(U)) {
1709 // Swap operands
1710 SI->swapValues();
1711 SI->swapProfMetadata();
1712 continue;
1713 }
1714 llvm_unreachable("Must be a branch or a select")__builtin_unreachable();
1715 }
1716 Cmp->setPredicate(CmpInst::getSwappedPredicate(DomPred));
1717 return true;
1718}
1719
1720bool CodeGenPrepare::optimizeCmp(CmpInst *Cmp, bool &ModifiedDT) {
1721 if (sinkCmpExpression(Cmp, *TLI))
1722 return true;
1723
1724 if (combineToUAddWithOverflow(Cmp, ModifiedDT))
1725 return true;
1726
1727 if (combineToUSubWithOverflow(Cmp, ModifiedDT))
1728 return true;
1729
1730 if (foldICmpWithDominatingICmp(Cmp, *TLI))
1731 return true;
1732
1733 return false;
1734}
1735
1736/// Duplicate and sink the given 'and' instruction into user blocks where it is
1737/// used in a compare to allow isel to generate better code for targets where
1738/// this operation can be combined.
1739///
1740/// Return true if any changes are made.
1741static bool sinkAndCmp0Expression(Instruction *AndI,
1742 const TargetLowering &TLI,
1743 SetOfInstrs &InsertedInsts) {
1744 // Double-check that we're not trying to optimize an instruction that was
1745 // already optimized by some other part of this pass.
1746 assert(!InsertedInsts.count(AndI) &&(static_cast<void> (0))
1747 "Attempting to optimize already optimized and instruction")(static_cast<void> (0));
1748 (void) InsertedInsts;
1749
1750 // Nothing to do for single use in same basic block.
1751 if (AndI->hasOneUse() &&
1752 AndI->getParent() == cast<Instruction>(*AndI->user_begin())->getParent())
1753 return false;
1754
1755 // Try to avoid cases where sinking/duplicating is likely to increase register
1756 // pressure.
1757 if (!isa<ConstantInt>(AndI->getOperand(0)) &&
1758 !isa<ConstantInt>(AndI->getOperand(1)) &&
1759 AndI->getOperand(0)->hasOneUse() && AndI->getOperand(1)->hasOneUse())
1760 return false;
1761
1762 for (auto *U : AndI->users()) {
1763 Instruction *User = cast<Instruction>(U);
1764
1765 // Only sink 'and' feeding icmp with 0.
1766 if (!isa<ICmpInst>(User))
1767 return false;
1768
1769 auto *CmpC = dyn_cast<ConstantInt>(User->getOperand(1));
1770 if (!CmpC || !CmpC->isZero())
1771 return false;
1772 }
1773
1774 if (!TLI.isMaskAndCmp0FoldingBeneficial(*AndI))
1775 return false;
1776
1777 LLVM_DEBUG(dbgs() << "found 'and' feeding only icmp 0;\n")do { } while (false);
1778 LLVM_DEBUG(AndI->getParent()->dump())do { } while (false);
1779
1780 // Push the 'and' into the same block as the icmp 0. There should only be
1781 // one (icmp (and, 0)) in each block, since CSE/GVN should have removed any
1782 // others, so we don't need to keep track of which BBs we insert into.
1783 for (Value::user_iterator UI = AndI->user_begin(), E = AndI->user_end();
1784 UI != E; ) {
1785 Use &TheUse = UI.getUse();
1786 Instruction *User = cast<Instruction>(*UI);
1787
1788 // Preincrement use iterator so we don't invalidate it.
1789 ++UI;
1790
1791 LLVM_DEBUG(dbgs() << "sinking 'and' use: " << *User << "\n")do { } while (false);
1792
1793 // Keep the 'and' in the same place if the use is already in the same block.
1794 Instruction *InsertPt =
1795 User->getParent() == AndI->getParent() ? AndI : User;
1796 Instruction *InsertedAnd =
1797 BinaryOperator::Create(Instruction::And, AndI->getOperand(0),
1798 AndI->getOperand(1), "", InsertPt);
1799 // Propagate the debug info.
1800 InsertedAnd->setDebugLoc(AndI->getDebugLoc());
1801
1802 // Replace a use of the 'and' with a use of the new 'and'.
1803 TheUse = InsertedAnd;
1804 ++NumAndUses;
1805 LLVM_DEBUG(User->getParent()->dump())do { } while (false);
1806 }
1807
1808 // We removed all uses, nuke the and.
1809 AndI->eraseFromParent();
1810 return true;
1811}
1812
1813/// Check if the candidates could be combined with a shift instruction, which
1814/// includes:
1815/// 1. Truncate instruction
1816/// 2. And instruction and the imm is a mask of the low bits:
1817/// imm & (imm+1) == 0
1818static bool isExtractBitsCandidateUse(Instruction *User) {
1819 if (!isa<TruncInst>(User)) {
1820 if (User->getOpcode() != Instruction::And ||
1821 !isa<ConstantInt>(User->getOperand(1)))
1822 return false;
1823
1824 const APInt &Cimm = cast<ConstantInt>(User->getOperand(1))->getValue();
1825
1826 if ((Cimm & (Cimm + 1)).getBoolValue())
1827 return false;
1828 }
1829 return true;
1830}
1831
1832/// Sink both shift and truncate instruction to the use of truncate's BB.
1833static bool
1834SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI,
1835 DenseMap<BasicBlock *, BinaryOperator *> &InsertedShifts,
1836 const TargetLowering &TLI, const DataLayout &DL) {
1837 BasicBlock *UserBB = User->getParent();
1838 DenseMap<BasicBlock *, CastInst *> InsertedTruncs;
1839 auto *TruncI = cast<TruncInst>(User);
1840 bool MadeChange = false;
1841
1842 for (Value::user_iterator TruncUI = TruncI->user_begin(),
1843 TruncE = TruncI->user_end();
1844 TruncUI != TruncE;) {
1845
1846 Use &TruncTheUse = TruncUI.getUse();
1847 Instruction *TruncUser = cast<Instruction>(*TruncUI);
1848 // Preincrement use iterator so we don't invalidate it.
1849
1850 ++TruncUI;
1851
1852 int ISDOpcode = TLI.InstructionOpcodeToISD(TruncUser->getOpcode());
1853 if (!ISDOpcode)
1854 continue;
1855
1856 // If the use is actually a legal node, there will not be an
1857 // implicit truncate.
1858 // FIXME: always querying the result type is just an
1859 // approximation; some nodes' legality is determined by the
1860 // operand or other means. There's no good way to find out though.
1861 if (TLI.isOperationLegalOrCustom(
1862 ISDOpcode, TLI.getValueType(DL, TruncUser->getType(), true)))
1863 continue;
1864
1865 // Don't bother for PHI nodes.
1866 if (isa<PHINode>(TruncUser))
1867 continue;
1868
1869 BasicBlock *TruncUserBB = TruncUser->getParent();
1870
1871 if (UserBB == TruncUserBB)
1872 continue;
1873
1874 BinaryOperator *&InsertedShift = InsertedShifts[TruncUserBB];
1875 CastInst *&InsertedTrunc = InsertedTruncs[TruncUserBB];
1876
1877 if (!InsertedShift && !InsertedTrunc) {
1878 BasicBlock::iterator InsertPt = TruncUserBB->getFirstInsertionPt();
1879 assert(InsertPt != TruncUserBB->end())(static_cast<void> (0));
1880 // Sink the shift
1881 if (ShiftI->getOpcode() == Instruction::AShr)
1882 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1883 "", &*InsertPt);
1884 else
1885 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1886 "", &*InsertPt);
1887 InsertedShift->setDebugLoc(ShiftI->getDebugLoc());
1888
1889 // Sink the trunc
1890 BasicBlock::iterator TruncInsertPt = TruncUserBB->getFirstInsertionPt();
1891 TruncInsertPt++;
1892 assert(TruncInsertPt != TruncUserBB->end())(static_cast<void> (0));
1893
1894 InsertedTrunc = CastInst::Create(TruncI->getOpcode(), InsertedShift,
1895 TruncI->getType(), "", &*TruncInsertPt);
1896 InsertedTrunc->setDebugLoc(TruncI->getDebugLoc());
1897
1898 MadeChange = true;
1899
1900 TruncTheUse = InsertedTrunc;
1901 }
1902 }
1903 return MadeChange;
1904}
1905
1906/// Sink the shift *right* instruction into user blocks if the uses could
1907/// potentially be combined with this shift instruction and generate BitExtract
1908/// instruction. It will only be applied if the architecture supports BitExtract
1909/// instruction. Here is an example:
1910/// BB1:
1911/// %x.extract.shift = lshr i64 %arg1, 32
1912/// BB2:
1913/// %x.extract.trunc = trunc i64 %x.extract.shift to i16
1914/// ==>
1915///
1916/// BB2:
1917/// %x.extract.shift.1 = lshr i64 %arg1, 32
1918/// %x.extract.trunc = trunc i64 %x.extract.shift.1 to i16
1919///
1920/// CodeGen will recognize the pattern in BB2 and generate BitExtract
1921/// instruction.
1922/// Return true if any changes are made.
1923static bool OptimizeExtractBits(BinaryOperator *ShiftI, ConstantInt *CI,
1924 const TargetLowering &TLI,
1925 const DataLayout &DL) {
1926 BasicBlock *DefBB = ShiftI->getParent();
1927
1928 /// Only insert instructions in each block once.
1929 DenseMap<BasicBlock *, BinaryOperator *> InsertedShifts;
1930
1931 bool shiftIsLegal = TLI.isTypeLegal(TLI.getValueType(DL, ShiftI->getType()));
1932
1933 bool MadeChange = false;
1934 for (Value::user_iterator UI = ShiftI->user_begin(), E = ShiftI->user_end();
1935 UI != E;) {
1936 Use &TheUse = UI.getUse();
1937 Instruction *User = cast<Instruction>(*UI);
1938 // Preincrement use iterator so we don't invalidate it.
1939 ++UI;
1940
1941 // Don't bother for PHI nodes.
1942 if (isa<PHINode>(User))
1943 continue;
1944
1945 if (!isExtractBitsCandidateUse(User))
1946 continue;
1947
1948 BasicBlock *UserBB = User->getParent();
1949
1950 if (UserBB == DefBB) {
1951 // If the shift and truncate instruction are in the same BB. The use of
1952 // the truncate(TruncUse) may still introduce another truncate if not
1953 // legal. In this case, we would like to sink both shift and truncate
1954 // instruction to the BB of TruncUse.
1955 // for example:
1956 // BB1:
1957 // i64 shift.result = lshr i64 opnd, imm
1958 // trunc.result = trunc shift.result to i16
1959 //
1960 // BB2:
1961 // ----> We will have an implicit truncate here if the architecture does
1962 // not have i16 compare.
1963 // cmp i16 trunc.result, opnd2
1964 //
1965 if (isa<TruncInst>(User) && shiftIsLegal
1966 // If the type of the truncate is legal, no truncate will be
1967 // introduced in other basic blocks.
1968 &&
1969 (!TLI.isTypeLegal(TLI.getValueType(DL, User->getType()))))
1970 MadeChange =
1971 SinkShiftAndTruncate(ShiftI, User, CI, InsertedShifts, TLI, DL);
1972
1973 continue;
1974 }
1975 // If we have already inserted a shift into this block, use it.
1976 BinaryOperator *&InsertedShift = InsertedShifts[UserBB];
1977
1978 if (!InsertedShift) {
1979 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1980 assert(InsertPt != UserBB->end())(static_cast<void> (0));
1981
1982 if (ShiftI->getOpcode() == Instruction::AShr)
1983 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1984 "", &*InsertPt);
1985 else
1986 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1987 "", &*InsertPt);
1988 InsertedShift->setDebugLoc(ShiftI->getDebugLoc());
1989
1990 MadeChange = true;
1991 }
1992
1993 // Replace a use of the shift with a use of the new shift.
1994 TheUse = InsertedShift;
1995 }
1996
1997 // If we removed all uses, or there are none, nuke the shift.
1998 if (ShiftI->use_empty()) {
1999 salvageDebugInfo(*ShiftI);
2000 ShiftI->eraseFromParent();
2001 MadeChange = true;
2002 }
2003
2004 return MadeChange;
2005}
2006
2007/// If counting leading or trailing zeros is an expensive operation and a zero
2008/// input is defined, add a check for zero to avoid calling the intrinsic.
2009///
2010/// We want to transform:
2011/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 false)
2012///
2013/// into:
2014/// entry:
2015/// %cmpz = icmp eq i64 %A, 0
2016/// br i1 %cmpz, label %cond.end, label %cond.false
2017/// cond.false:
2018/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 true)
2019/// br label %cond.end
2020/// cond.end:
2021/// %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ]
2022///
2023/// If the transform is performed, return true and set ModifiedDT to true.
2024static bool despeculateCountZeros(IntrinsicInst *CountZeros,
2025 const TargetLowering *TLI,
2026 const DataLayout *DL,
2027 bool &ModifiedDT) {
2028 // If a zero input is undefined, it doesn't make sense to despeculate that.
2029 if (match(CountZeros->getOperand(1), m_One()))
2030 return false;
2031
2032 // If it's cheap to speculate, there's nothing to do.
2033 auto IntrinsicID = CountZeros->getIntrinsicID();
2034 if ((IntrinsicID == Intrinsic::cttz && TLI->isCheapToSpeculateCttz()) ||
2035 (IntrinsicID == Intrinsic::ctlz && TLI->isCheapToSpeculateCtlz()))
2036 return false;
2037
2038 // Only handle legal scalar cases. Anything else requires too much work.
2039 Type *Ty = CountZeros->getType();
2040 unsigned SizeInBits = Ty->getPrimitiveSizeInBits();
2041 if (Ty->isVectorTy() || SizeInBits > DL->getLargestLegalIntTypeSizeInBits())
2042 return false;
2043
2044 // Bail if the value is never zero.
2045 if (llvm::isKnownNonZero(CountZeros->getOperand(0), *DL))
2046 return false;
2047
2048 // The intrinsic will be sunk behind a compare against zero and branch.
2049 BasicBlock *StartBlock = CountZeros->getParent();
2050 BasicBlock *CallBlock = StartBlock->splitBasicBlock(CountZeros, "cond.false");
2051
2052 // Create another block after the count zero intrinsic. A PHI will be added
2053 // in this block to select the result of the intrinsic or the bit-width
2054 // constant if the input to the intrinsic is zero.
2055 BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(CountZeros));
2056 BasicBlock *EndBlock = CallBlock->splitBasicBlock(SplitPt, "cond.end");
2057
2058 // Set up a builder to create a compare, conditional branch, and PHI.
2059 IRBuilder<> Builder(CountZeros->getContext());
2060 Builder.SetInsertPoint(StartBlock->getTerminator());
2061 Builder.SetCurrentDebugLocation(CountZeros->getDebugLoc());
2062
2063 // Replace the unconditional branch that was created by the first split with
2064 // a compare against zero and a conditional branch.
2065 Value *Zero = Constant::getNullValue(Ty);
2066 Value *Cmp = Builder.CreateICmpEQ(CountZeros->getOperand(0), Zero, "cmpz");
2067 Builder.CreateCondBr(Cmp, EndBlock, CallBlock);
2068 StartBlock->getTerminator()->eraseFromParent();
2069
2070 // Create a PHI in the end block to select either the output of the intrinsic
2071 // or the bit width of the operand.
2072 Builder.SetInsertPoint(&EndBlock->front());
2073 PHINode *PN = Builder.CreatePHI(Ty, 2, "ctz");
2074 CountZeros->replaceAllUsesWith(PN);
2075 Value *BitWidth = Builder.getInt(APInt(SizeInBits, SizeInBits));
2076 PN->addIncoming(BitWidth, StartBlock);
2077 PN->addIncoming(CountZeros, CallBlock);
2078
2079 // We are explicitly handling the zero case, so we can set the intrinsic's
2080 // undefined zero argument to 'true'. This will also prevent reprocessing the
2081 // intrinsic; we only despeculate when a zero input is defined.
2082 CountZeros->setArgOperand(1, Builder.getTrue());
2083 ModifiedDT = true;
2084 return true;
2085}
2086
2087bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool &ModifiedDT) {
2088 BasicBlock *BB = CI->getParent();
2089
2090 // Lower inline assembly if we can.
2091 // If we found an inline asm expession, and if the target knows how to
2092 // lower it to normal LLVM code, do so now.
2093 if (CI->isInlineAsm()) {
2094 if (TLI->ExpandInlineAsm(CI)) {
2095 // Avoid invalidating the iterator.
2096 CurInstIterator = BB->begin();
2097 // Avoid processing instructions out of order, which could cause
2098 // reuse before a value is defined.
2099 SunkAddrs.clear();
2100 return true;
2101 }
2102 // Sink address computing for memory operands into the block.
2103 if (optimizeInlineAsmInst(CI))
2104 return true;
2105 }
2106
2107 // Align the pointer arguments to this call if the target thinks it's a good
2108 // idea
2109 unsigned MinSize, PrefAlign;
2110 if (TLI->shouldAlignPointerArgs(CI, MinSize, PrefAlign)) {
2111 for (auto &Arg : CI->arg_operands()) {
2112 // We want to align both objects whose address is used directly and
2113 // objects whose address is used in casts and GEPs, though it only makes
2114 // sense for GEPs if the offset is a multiple of the desired alignment and
2115 // if size - offset meets the size threshold.
2116 if (!Arg->getType()->isPointerTy())
2117 continue;
2118 APInt Offset(DL->getIndexSizeInBits(
2119 cast<PointerType>(Arg->getType())->getAddressSpace()),
2120 0);
2121 Value *Val = Arg->stripAndAccumulateInBoundsConstantOffsets(*DL, Offset);
2122 uint64_t Offset2 = Offset.getLimitedValue();
2123 if ((Offset2 & (PrefAlign-1)) != 0)
2124 continue;
2125 AllocaInst *AI;
2126 if ((AI = dyn_cast<AllocaInst>(Val)) && AI->getAlignment() < PrefAlign &&
2127 DL->getTypeAllocSize(AI->getAllocatedType()) >= MinSize + Offset2)
2128 AI->setAlignment(Align(PrefAlign));
2129 // Global variables can only be aligned if they are defined in this
2130 // object (i.e. they are uniquely initialized in this object), and
2131 // over-aligning global variables that have an explicit section is
2132 // forbidden.
2133 GlobalVariable *GV;
2134 if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() &&
2135 GV->getPointerAlignment(*DL) < PrefAlign &&
2136 DL->getTypeAllocSize(GV->getValueType()) >=
2137 MinSize + Offset2)
2138 GV->setAlignment(MaybeAlign(PrefAlign));
2139 }
2140 // If this is a memcpy (or similar) then we may be able to improve the
2141 // alignment
2142 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(CI)) {
2143 Align DestAlign = getKnownAlignment(MI->getDest(), *DL);
2144 MaybeAlign MIDestAlign = MI->getDestAlign();
2145 if (!MIDestAlign || DestAlign > *MIDestAlign)
2146 MI->setDestAlignment(DestAlign);
2147 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
2148 MaybeAlign MTISrcAlign = MTI->getSourceAlign();
2149 Align SrcAlign = getKnownAlignment(MTI->getSource(), *DL);
2150 if (!MTISrcAlign || SrcAlign > *MTISrcAlign)
2151 MTI->setSourceAlignment(SrcAlign);
2152 }
2153 }
2154 }
2155
2156 // If we have a cold call site, try to sink addressing computation into the
2157 // cold block. This interacts with our handling for loads and stores to
2158 // ensure that we can fold all uses of a potential addressing computation
2159 // into their uses. TODO: generalize this to work over profiling data
2160 if (CI->hasFnAttr(Attribute::Cold) &&
2161 !OptSize && !llvm::shouldOptimizeForSize(BB, PSI, BFI.get()))
2162 for (auto &Arg : CI->arg_operands()) {
2163 if (!Arg->getType()->isPointerTy())
2164 continue;
2165 unsigned AS = Arg->getType()->getPointerAddressSpace();
2166 return optimizeMemoryInst(CI, Arg, Arg->getType(), AS);
2167 }
2168
2169 IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
2170 if (II) {
2171 switch (II->getIntrinsicID()) {
2172 default: break;
2173 case Intrinsic::assume:
2174 llvm_unreachable("llvm.assume should have been removed already")__builtin_unreachable();
2175 case Intrinsic::experimental_widenable_condition: {
2176 // Give up on future widening oppurtunties so that we can fold away dead
2177 // paths and merge blocks before going into block-local instruction
2178 // selection.
2179 if (II->use_empty()) {
2180 II->eraseFromParent();
2181 return true;
2182 }
2183 Constant *RetVal = ConstantInt::getTrue(II->getContext());
2184 resetIteratorIfInvalidatedWhileCalling(BB, [&]() {
2185 replaceAndRecursivelySimplify(CI, RetVal, TLInfo, nullptr);
2186 });
2187 return true;
2188 }
2189 case Intrinsic::objectsize:
2190 llvm_unreachable("llvm.objectsize.* should have been lowered already")__builtin_unreachable();
2191 case Intrinsic::is_constant:
2192 llvm_unreachable("llvm.is.constant.* should have been lowered already")__builtin_unreachable();
2193 case Intrinsic::aarch64_stlxr:
2194 case Intrinsic::aarch64_stxr: {
2195 ZExtInst *ExtVal = dyn_cast<ZExtInst>(CI->getArgOperand(0));
2196 if (!ExtVal || !ExtVal->hasOneUse() ||
2197 ExtVal->getParent() == CI->getParent())
2198 return false;
2199 // Sink a zext feeding stlxr/stxr before it, so it can be folded into it.
2200 ExtVal->moveBefore(CI);
2201 // Mark this instruction as "inserted by CGP", so that other
2202 // optimizations don't touch it.
2203 InsertedInsts.insert(ExtVal);
2204 return true;
2205 }
2206
2207 case Intrinsic::launder_invariant_group:
2208 case Intrinsic::strip_invariant_group: {
2209 Value *ArgVal = II->getArgOperand(0);
2210 auto it = LargeOffsetGEPMap.find(II);
2211 if (it != LargeOffsetGEPMap.end()) {
2212 // Merge entries in LargeOffsetGEPMap to reflect the RAUW.
2213 // Make sure not to have to deal with iterator invalidation
2214 // after possibly adding ArgVal to LargeOffsetGEPMap.
2215 auto GEPs = std::move(it->second);
2216 LargeOffsetGEPMap[ArgVal].append(GEPs.begin(), GEPs.end());
2217 LargeOffsetGEPMap.erase(II);
2218 }
2219
2220 II->replaceAllUsesWith(ArgVal);
2221 II->eraseFromParent();
2222 return true;
2223 }
2224 case Intrinsic::cttz:
2225 case Intrinsic::ctlz:
2226 // If counting zeros is expensive, try to avoid it.
2227 return despeculateCountZeros(II, TLI, DL, ModifiedDT);
2228 case Intrinsic::fshl:
2229 case Intrinsic::fshr:
2230 return optimizeFunnelShift(II);
2231 case Intrinsic::dbg_value:
2232 return fixupDbgValue(II);
2233 case Intrinsic::vscale: {
2234 // If datalayout has no special restrictions on vector data layout,
2235 // replace `llvm.vscale` by an equivalent constant expression
2236 // to benefit from cheap constant propagation.
2237 Type *ScalableVectorTy =
2238 VectorType::get(Type::getInt8Ty(II->getContext()), 1, true);
2239 if (DL->getTypeAllocSize(ScalableVectorTy).getKnownMinSize() == 8) {
2240 auto *Null = Constant::getNullValue(ScalableVectorTy->getPointerTo());
2241 auto *One = ConstantInt::getSigned(II->getType(), 1);
2242 auto *CGep =
2243 ConstantExpr::getGetElementPtr(ScalableVectorTy, Null, One);
2244 II->replaceAllUsesWith(ConstantExpr::getPtrToInt(CGep, II->getType()));
2245 II->eraseFromParent();
2246 return true;
2247 }
2248 break;
2249 }
2250 case Intrinsic::masked_gather:
2251 return optimizeGatherScatterInst(II, II->getArgOperand(0));
2252 case Intrinsic::masked_scatter:
2253 return optimizeGatherScatterInst(II, II->getArgOperand(1));
2254 }
2255
2256 SmallVector<Value *, 2> PtrOps;
2257 Type *AccessTy;
2258 if (TLI->getAddrModeArguments(II, PtrOps, AccessTy))
2259 while (!PtrOps.empty()) {
2260 Value *PtrVal = PtrOps.pop_back_val();
2261 unsigned AS = PtrVal->getType()->getPointerAddressSpace();
2262 if (optimizeMemoryInst(II, PtrVal, AccessTy, AS))
2263 return true;
2264 }
2265 }
2266
2267 // From here on out we're working with named functions.
2268 if (!CI->getCalledFunction()) return false;
2269
2270 // Lower all default uses of _chk calls. This is very similar
2271 // to what InstCombineCalls does, but here we are only lowering calls
2272 // to fortified library functions (e.g. __memcpy_chk) that have the default
2273 // "don't know" as the objectsize. Anything else should be left alone.
2274 FortifiedLibCallSimplifier Simplifier(TLInfo, true);
2275 IRBuilder<> Builder(CI);
2276 if (Value *V = Simplifier.optimizeCall(CI, Builder)) {
2277 CI->replaceAllUsesWith(V);
2278 CI->eraseFromParent();
2279 return true;
2280 }
2281
2282 return false;
2283}
2284
2285/// Look for opportunities to duplicate return instructions to the predecessor
2286/// to enable tail call optimizations. The case it is currently looking for is:
2287/// @code
2288/// bb0:
2289/// %tmp0 = tail call i32 @f0()
2290/// br label %return
2291/// bb1:
2292/// %tmp1 = tail call i32 @f1()
2293/// br label %return
2294/// bb2:
2295/// %tmp2 = tail call i32 @f2()
2296/// br label %return
2297/// return:
2298/// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
2299/// ret i32 %retval
2300/// @endcode
2301///
2302/// =>
2303///
2304/// @code
2305/// bb0:
2306/// %tmp0 = tail call i32 @f0()
2307/// ret i32 %tmp0
2308/// bb1:
2309/// %tmp1 = tail call i32 @f1()
2310/// ret i32 %tmp1
2311/// bb2:
2312/// %tmp2 = tail call i32 @f2()
2313/// ret i32 %tmp2
2314/// @endcode
2315bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT) {
2316 ReturnInst *RetI = dyn_cast<ReturnInst>(BB->getTerminator());
2317 if (!RetI)
2318 return false;
2319
2320 PHINode *PN = nullptr;
2321 ExtractValueInst *EVI = nullptr;
2322 BitCastInst *BCI = nullptr;
2323 Value *V = RetI->getReturnValue();
2324 if (V) {
2325 BCI = dyn_cast<BitCastInst>(V);
2326 if (BCI)
2327 V = BCI->getOperand(0);
2328
2329 EVI = dyn_cast<ExtractValueInst>(V);
2330 if (EVI) {
2331 V = EVI->getOperand(0);
2332 if (!llvm::all_of(EVI->indices(), [](unsigned idx) { return idx == 0; }))
2333 return false;
2334 }
2335
2336 PN = dyn_cast<PHINode>(V);
2337 if (!PN)
2338 return false;
2339 }
2340
2341 if (PN && PN->getParent() != BB)
2342 return false;
2343
2344 auto isLifetimeEndOrBitCastFor = [](const Instruction *Inst) {
2345 const BitCastInst *BC = dyn_cast<BitCastInst>(Inst);
2346 if (BC && BC->hasOneUse())
2347 Inst = BC->user_back();
2348
2349 if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst))
2350 return II->getIntrinsicID() == Intrinsic::lifetime_end;
2351 return false;
2352 };
2353
2354 // Make sure there are no instructions between the first instruction
2355 // and return.
2356 const Instruction *BI = BB->getFirstNonPHI();
2357 // Skip over debug and the bitcast.
2358 while (isa<DbgInfoIntrinsic>(BI) || BI == BCI || BI == EVI ||
2359 isa<PseudoProbeInst>(BI) || isLifetimeEndOrBitCastFor(BI))
2360 BI = BI->getNextNode();
2361 if (BI != RetI)
2362 return false;
2363
2364 /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
2365 /// call.
2366 const Function *F = BB->getParent();
2367 SmallVector<BasicBlock*, 4> TailCallBBs;
2368 if (PN) {
2369 for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
2370 // Look through bitcasts.
2371 Value *IncomingVal = PN->getIncomingValue(I)->stripPointerCasts();
2372 CallInst *CI = dyn_cast<CallInst>(IncomingVal);
2373 BasicBlock *PredBB = PN->getIncomingBlock(I);
2374 // Make sure the phi value is indeed produced by the tail call.
2375 if (CI && CI->hasOneUse() && CI->getParent() == PredBB &&
2376 TLI->mayBeEmittedAsTailCall(CI) &&
2377 attributesPermitTailCall(F, CI, RetI, *TLI))
2378 TailCallBBs.push_back(PredBB);
2379 }
2380 } else {
2381 SmallPtrSet<BasicBlock*, 4> VisitedBBs;
2382 for (BasicBlock *Pred : predecessors(BB)) {
2383 if (!VisitedBBs.insert(Pred).second)
2384 continue;
2385 if (Instruction *I = Pred->rbegin()->getPrevNonDebugInstruction(true)) {
2386 CallInst *CI = dyn_cast<CallInst>(I);
2387 if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI) &&
2388 attributesPermitTailCall(F, CI, RetI, *TLI))
2389 TailCallBBs.push_back(Pred);
2390 }
2391 }
2392 }
2393
2394 bool Changed = false;
2395 for (auto const &TailCallBB : TailCallBBs) {
2396 // Make sure the call instruction is followed by an unconditional branch to
2397 // the return block.
2398 BranchInst *BI = dyn_cast<BranchInst>(TailCallBB->getTerminator());
2399 if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
2400 continue;
2401
2402 // Duplicate the return into TailCallBB.
2403 (void)FoldReturnIntoUncondBranch(RetI, BB, TailCallBB);
2404 assert(!VerifyBFIUpdates ||(static_cast<void> (0))
2405 BFI->getBlockFreq(BB) >= BFI->getBlockFreq(TailCallBB))(static_cast<void> (0));
2406 BFI->setBlockFreq(
2407 BB,
2408 (BFI->getBlockFreq(BB) - BFI->getBlockFreq(TailCallBB)).getFrequency());
2409 ModifiedDT = Changed = true;
2410 ++NumRetsDup;
2411 }
2412
2413 // If we eliminated all predecessors of the block, delete the block now.
2414 if (Changed && !BB->hasAddressTaken() && pred_empty(BB))
2415 BB->eraseFromParent();
2416
2417 return Changed;
2418}
2419
2420//===----------------------------------------------------------------------===//
2421// Memory Optimization
2422//===----------------------------------------------------------------------===//
2423
2424namespace {
2425
2426/// This is an extended version of TargetLowering::AddrMode
2427/// which holds actual Value*'s for register values.
2428struct ExtAddrMode : public TargetLowering::AddrMode {
2429 Value *BaseReg = nullptr;
2430 Value *ScaledReg = nullptr;
2431 Value *OriginalValue = nullptr;
2432 bool InBounds = true;
2433
2434 enum FieldName {
2435 NoField = 0x00,
2436 BaseRegField = 0x01,
2437 BaseGVField = 0x02,
2438 BaseOffsField = 0x04,
2439 ScaledRegField = 0x08,
2440 ScaleField = 0x10,
2441 MultipleFields = 0xff
2442 };
2443
2444
2445 ExtAddrMode() = default;
2446
2447 void print(raw_ostream &OS) const;
2448 void dump() const;
2449
2450 FieldName compare(const ExtAddrMode &other) {
2451 // First check that the types are the same on each field, as differing types
2452 // is something we can't cope with later on.
2453 if (BaseReg && other.BaseReg &&
2454 BaseReg->getType() != other.BaseReg->getType())
2455 return MultipleFields;
2456 if (BaseGV && other.BaseGV &&
2457 BaseGV->getType() != other.BaseGV->getType())
2458 return MultipleFields;
2459 if (ScaledReg && other.ScaledReg &&
2460 ScaledReg->getType() != other.ScaledReg->getType())
2461 return MultipleFields;
2462
2463 // Conservatively reject 'inbounds' mismatches.
2464 if (InBounds != other.InBounds)
2465 return MultipleFields;
2466
2467 // Check each field to see if it differs.
2468 unsigned Result = NoField;
2469 if (BaseReg != other.BaseReg)
2470 Result |= BaseRegField;
2471 if (BaseGV != other.BaseGV)
2472 Result |= BaseGVField;
2473 if (BaseOffs != other.BaseOffs)
2474 Result |= BaseOffsField;
2475 if (ScaledReg != other.ScaledReg)
2476 Result |= ScaledRegField;
2477 // Don't count 0 as being a different scale, because that actually means
2478 // unscaled (which will already be counted by having no ScaledReg).
2479 if (Scale && other.Scale && Scale != other.Scale)
2480 Result |= ScaleField;
2481
2482 if (countPopulation(Result) > 1)
2483 return MultipleFields;
2484 else
2485 return static_cast<FieldName>(Result);
2486 }
2487
2488 // An AddrMode is trivial if it involves no calculation i.e. it is just a base
2489 // with no offset.
2490 bool isTrivial() {
2491 // An AddrMode is (BaseGV + BaseReg + BaseOffs + ScaleReg * Scale) so it is
2492 // trivial if at most one of these terms is nonzero, except that BaseGV and
2493 // BaseReg both being zero actually means a null pointer value, which we
2494 // consider to be 'non-zero' here.
2495 return !BaseOffs && !Scale && !(BaseGV && BaseReg);
2496 }
2497
2498 Value *GetFieldAsValue(FieldName Field, Type *IntPtrTy) {
2499 switch (Field) {
2500 default:
2501 return nullptr;
2502 case BaseRegField:
2503 return BaseReg;
2504 case BaseGVField:
2505 return BaseGV;
2506 case ScaledRegField:
2507 return ScaledReg;
2508 case BaseOffsField:
2509 return ConstantInt::get(IntPtrTy, BaseOffs);
2510 }
2511 }
2512
2513 void SetCombinedField(FieldName Field, Value *V,
2514 const SmallVectorImpl<ExtAddrMode> &AddrModes) {
2515 switch (Field) {
2516 default:
2517 llvm_unreachable("Unhandled fields are expected to be rejected earlier")__builtin_unreachable();
2518 break;
2519 case ExtAddrMode::BaseRegField:
2520 BaseReg = V;
2521 break;
2522 case ExtAddrMode::BaseGVField:
2523 // A combined BaseGV is an Instruction, not a GlobalValue, so it goes
2524 // in the BaseReg field.
2525 assert(BaseReg == nullptr)(static_cast<void> (0));
2526 BaseReg = V;
2527 BaseGV = nullptr;
2528 break;
2529 case ExtAddrMode::ScaledRegField:
2530 ScaledReg = V;
2531 // If we have a mix of scaled and unscaled addrmodes then we want scale
2532 // to be the scale and not zero.
2533 if (!Scale)
2534 for (const ExtAddrMode &AM : AddrModes)
2535 if (AM.Scale) {
2536 Scale = AM.Scale;
2537 break;
2538 }
2539 break;
2540 case ExtAddrMode::BaseOffsField:
2541 // The offset is no longer a constant, so it goes in ScaledReg with a
2542 // scale of 1.
2543 assert(ScaledReg == nullptr)(static_cast<void> (0));
2544 ScaledReg = V;
2545 Scale = 1;
2546 BaseOffs = 0;
2547 break;
2548 }
2549 }
2550};
2551
2552} // end anonymous namespace
2553
2554#ifndef NDEBUG1
2555static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
2556 AM.print(OS);
2557 return OS;
2558}
2559#endif
2560
2561#if !defined(NDEBUG1) || defined(LLVM_ENABLE_DUMP)
2562void ExtAddrMode::print(raw_ostream &OS) const {
2563 bool NeedPlus = false;
2564 OS << "[";
2565 if (InBounds)
2566 OS << "inbounds ";
2567 if (BaseGV) {
2568 OS << (NeedPlus ? " + " : "")
2569 << "GV:";
2570 BaseGV->printAsOperand(OS, /*PrintType=*/false);
2571 NeedPlus = true;
2572 }
2573
2574 if (BaseOffs) {
2575 OS << (NeedPlus ? " + " : "")
2576 << BaseOffs;
2577 NeedPlus = true;
2578 }
2579
2580 if (BaseReg) {
2581 OS << (NeedPlus ? " + " : "")
2582 << "Base:";
2583 BaseReg->printAsOperand(OS, /*PrintType=*/false);
2584 NeedPlus = true;
2585 }
2586 if (Scale) {
2587 OS << (NeedPlus ? " + " : "")
2588 << Scale << "*";
2589 ScaledReg->printAsOperand(OS, /*PrintType=*/false);
2590 }
2591
2592 OS << ']';
2593}
2594
2595LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void ExtAddrMode::dump() const {
2596 print(dbgs());
2597 dbgs() << '\n';
2598}
2599#endif
2600
2601namespace {
2602
2603/// This class provides transaction based operation on the IR.
2604/// Every change made through this class is recorded in the internal state and
2605/// can be undone (rollback) until commit is called.
2606/// CGP does not check if instructions could be speculatively executed when
2607/// moved. Preserving the original location would pessimize the debugging
2608/// experience, as well as negatively impact the quality of sample PGO.
2609class TypePromotionTransaction {
2610 /// This represents the common interface of the individual transaction.
2611 /// Each class implements the logic for doing one specific modification on
2612 /// the IR via the TypePromotionTransaction.
2613 class TypePromotionAction {
2614 protected:
2615 /// The Instruction modified.
2616 Instruction *Inst;
2617
2618 public:
2619 /// Constructor of the action.
2620 /// The constructor performs the related action on the IR.
2621 TypePromotionAction(Instruction *Inst) : Inst(Inst) {}
2622
2623 virtual ~TypePromotionAction() = default;
2624
2625 /// Undo the modification done by this action.
2626 /// When this method is called, the IR must be in the same state as it was
2627 /// before this action was applied.
2628 /// \pre Undoing the action works if and only if the IR is in the exact same
2629 /// state as it was directly after this action was applied.
2630 virtual void undo() = 0;
2631
2632 /// Advocate every change made by this action.
2633 /// When the results on the IR of the action are to be kept, it is important
2634 /// to call this function, otherwise hidden information may be kept forever.
2635 virtual void commit() {
2636 // Nothing to be done, this action is not doing anything.
2637 }
2638 };
2639
2640 /// Utility to remember the position of an instruction.
2641 class InsertionHandler {
2642 /// Position of an instruction.
2643 /// Either an instruction:
2644 /// - Is the first in a basic block: BB is used.
2645 /// - Has a previous instruction: PrevInst is used.
2646 union {
2647 Instruction *PrevInst;
2648 BasicBlock *BB;
2649 } Point;
2650
2651 /// Remember whether or not the instruction had a previous instruction.
2652 bool HasPrevInstruction;
2653
2654 public:
2655 /// Record the position of \p Inst.
2656 InsertionHandler(Instruction *Inst) {
2657 BasicBlock::iterator It = Inst->getIterator();
2658 HasPrevInstruction = (It != (Inst->getParent()->begin()));
2659 if (HasPrevInstruction)
2660 Point.PrevInst = &*--It;
2661 else
2662 Point.BB = Inst->getParent();
2663 }
2664
2665 /// Insert \p Inst at the recorded position.
2666 void insert(Instruction *Inst) {
2667 if (HasPrevInstruction) {
2668 if (Inst->getParent())
2669 Inst->removeFromParent();
2670 Inst->insertAfter(Point.PrevInst);
2671 } else {
2672 Instruction *Position = &*Point.BB->getFirstInsertionPt();
2673 if (Inst->getParent())
2674 Inst->moveBefore(Position);
2675 else
2676 Inst->insertBefore(Position);
2677 }
2678 }
2679 };
2680
2681 /// Move an instruction before another.
2682 class InstructionMoveBefore : public TypePromotionAction {
2683 /// Original position of the instruction.
2684 InsertionHandler Position;
2685
2686 public:
2687 /// Move \p Inst before \p Before.
2688 InstructionMoveBefore(Instruction *Inst, Instruction *Before)
2689 : TypePromotionAction(Inst), Position(Inst) {
2690 LLVM_DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Beforedo { } while (false)
2691 << "\n")do { } while (false);
2692 Inst->moveBefore(Before);
2693 }
2694
2695 /// Move the instruction back to its original position.
2696 void undo() override {
2697 LLVM_DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n")do { } while (false);
2698 Position.insert(Inst);
2699 }
2700 };
2701
2702 /// Set the operand of an instruction with a new value.
2703 class OperandSetter : public TypePromotionAction {
2704 /// Original operand of the instruction.
2705 Value *Origin;
2706
2707 /// Index of the modified instruction.
2708 unsigned Idx;
2709
2710 public:
2711 /// Set \p Idx operand of \p Inst with \p NewVal.
2712 OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
2713 : TypePromotionAction(Inst), Idx(Idx) {
2714 LLVM_DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"do { } while (false)
2715 << "for:" << *Inst << "\n"do { } while (false)
2716 << "with:" << *NewVal << "\n")do { } while (false);
2717 Origin = Inst->getOperand(Idx);
2718 Inst->setOperand(Idx, NewVal);
2719 }
2720
2721 /// Restore the original value of the instruction.
2722 void undo() override {
2723 LLVM_DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"do { } while (false)
2724 << "for: " << *Inst << "\n"do { } while (false)
2725 << "with: " << *Origin << "\n")do { } while (false);
2726 Inst->setOperand(Idx, Origin);
2727 }
2728 };
2729
2730 /// Hide the operands of an instruction.
2731 /// Do as if this instruction was not using any of its operands.
2732 class OperandsHider : public TypePromotionAction {
2733 /// The list of original operands.
2734 SmallVector<Value *, 4> OriginalValues;
2735
2736 public:
2737 /// Remove \p Inst from the uses of the operands of \p Inst.
2738 OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
2739 LLVM_DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n")do { } while (false);
2740 unsigned NumOpnds = Inst->getNumOperands();
2741 OriginalValues.reserve(NumOpnds);
2742 for (unsigned It = 0; It < NumOpnds; ++It) {
2743 // Save the current operand.
2744 Value *Val = Inst->getOperand(It);
2745 OriginalValues.push_back(Val);
2746 // Set a dummy one.
2747 // We could use OperandSetter here, but that would imply an overhead
2748 // that we are not willing to pay.
2749 Inst->setOperand(It, UndefValue::get(Val->getType()));
2750 }
2751 }
2752
2753 /// Restore the original list of uses.
2754 void undo() override {
2755 LLVM_DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n")do { } while (false);
2756 for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
2757 Inst->setOperand(It, OriginalValues[It]);
2758 }
2759 };
2760
2761 /// Build a truncate instruction.
2762 class TruncBuilder : public TypePromotionAction {
2763 Value *Val;
2764
2765 public:
2766 /// Build a truncate instruction of \p Opnd producing a \p Ty
2767 /// result.
2768 /// trunc Opnd to Ty.
2769 TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
2770 IRBuilder<> Builder(Opnd);
2771 Builder.SetCurrentDebugLocation(DebugLoc());
2772 Val = Builder.CreateTrunc(Opnd, Ty, "promoted");
2773 LLVM_DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n")do { } while (false);
2774 }
2775
2776 /// Get the built value.
2777 Value *getBuiltValue() { return Val; }
2778
2779 /// Remove the built instruction.
2780 void undo() override {
2781 LLVM_DEBUG(dbgs() << "Undo: TruncBuilder: " << *Val << "\n")do { } while (false);
2782 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2783 IVal->eraseFromParent();
2784 }
2785 };
2786
2787 /// Build a sign extension instruction.
2788 class SExtBuilder : public TypePromotionAction {
2789 Value *Val;
2790
2791 public:
2792 /// Build a sign extension instruction of \p Opnd producing a \p Ty
2793 /// result.
2794 /// sext Opnd to Ty.
2795 SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2796 : TypePromotionAction(InsertPt) {
2797 IRBuilder<> Builder(InsertPt);
2798 Val = Builder.CreateSExt(Opnd, Ty, "promoted");
2799 LLVM_DEBUG(dbgs() << "Do: SExtBuilder: " << *Val << "\n")do { } while (false);
2800 }
2801
2802 /// Get the built value.
2803 Value *getBuiltValue() { return Val; }
2804
2805 /// Remove the built instruction.
2806 void undo() override {
2807 LLVM_DEBUG(dbgs() << "Undo: SExtBuilder: " << *Val << "\n")do { } while (false);
2808 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2809 IVal->eraseFromParent();
2810 }
2811 };
2812
2813 /// Build a zero extension instruction.
2814 class ZExtBuilder : public TypePromotionAction {
2815 Value *Val;
2816
2817 public:
2818 /// Build a zero extension instruction of \p Opnd producing a \p Ty
2819 /// result.
2820 /// zext Opnd to Ty.
2821 ZExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2822 : TypePromotionAction(InsertPt) {
2823 IRBuilder<> Builder(InsertPt);
2824 Builder.SetCurrentDebugLocation(DebugLoc());
2825 Val = Builder.CreateZExt(Opnd, Ty, "promoted");
2826 LLVM_DEBUG(dbgs() << "Do: ZExtBuilder: " << *Val << "\n")do { } while (false);
2827 }
2828
2829 /// Get the built value.
2830 Value *getBuiltValue() { return Val; }
2831
2832 /// Remove the built instruction.
2833 void undo() override {
2834 LLVM_DEBUG(dbgs() << "Undo: ZExtBuilder: " << *Val << "\n")do { } while (false);
2835 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2836 IVal->eraseFromParent();
2837 }
2838 };
2839
2840 /// Mutate an instruction to another type.
2841 class TypeMutator : public TypePromotionAction {
2842 /// Record the original type.
2843 Type *OrigTy;
2844
2845 public:
2846 /// Mutate the type of \p Inst into \p NewTy.
2847 TypeMutator(Instruction *Inst, Type *NewTy)
2848 : TypePromotionAction(Inst), OrigTy(Inst->getType()) {
2849 LLVM_DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTydo { } while (false)
2850 << "\n")do { } while (false);
2851 Inst->mutateType(NewTy);
2852 }
2853
2854 /// Mutate the instruction back to its original type.
2855 void undo() override {
2856 LLVM_DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTydo { } while (false)
2857 << "\n")do { } while (false);
2858 Inst->mutateType(OrigTy);
2859 }
2860 };
2861
2862 /// Replace the uses of an instruction by another instruction.
2863 class UsesReplacer : public TypePromotionAction {
2864 /// Helper structure to keep track of the replaced uses.
2865 struct InstructionAndIdx {
2866 /// The instruction using the instruction.
2867 Instruction *Inst;
2868
2869 /// The index where this instruction is used for Inst.
2870 unsigned Idx;
2871
2872 InstructionAndIdx(Instruction *Inst, unsigned Idx)
2873 : Inst(Inst), Idx(Idx) {}
2874 };
2875
2876 /// Keep track of the original uses (pair Instruction, Index).
2877 SmallVector<InstructionAndIdx, 4> OriginalUses;
2878 /// Keep track of the debug users.
2879 SmallVector<DbgValueInst *, 1> DbgValues;
2880
2881 /// Keep track of the new value so that we can undo it by replacing
2882 /// instances of the new value with the original value.
2883 Value *New;
2884
2885 using use_iterator = SmallVectorImpl<InstructionAndIdx>::iterator;
2886
2887 public:
2888 /// Replace all the use of \p Inst by \p New.
2889 UsesReplacer(Instruction *Inst, Value *New)
2890 : TypePromotionAction(Inst), New(New) {
2891 LLVM_DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *Newdo { } while (false)
2892 << "\n")do { } while (false);
2893 // Record the original uses.
2894 for (Use &U : Inst->uses()) {
2895 Instruction *UserI = cast<Instruction>(U.getUser());
2896 OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo()));
2897 }
2898 // Record the debug uses separately. They are not in the instruction's
2899 // use list, but they are replaced by RAUW.
2900 findDbgValues(DbgValues, Inst);
2901
2902 // Now, we can replace the uses.
2903 Inst->replaceAllUsesWith(New);
2904 }
2905
2906 /// Reassign the original uses of Inst to Inst.
2907 void undo() override {
2908 LLVM_DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n")do { } while (false);
2909 for (InstructionAndIdx &Use : OriginalUses)
2910 Use.Inst->setOperand(Use.Idx, Inst);
2911 // RAUW has replaced all original uses with references to the new value,
2912 // including the debug uses. Since we are undoing the replacements,
2913 // the original debug uses must also be reinstated to maintain the
2914 // correctness and utility of debug value instructions.
2915 for (auto *DVI : DbgValues)
2916 DVI->replaceVariableLocationOp(New, Inst);
2917 }
2918 };
2919
2920 /// Remove an instruction from the IR.
2921 class InstructionRemover : public TypePromotionAction {
2922 /// Original position of the instruction.
2923 InsertionHandler Inserter;
2924
2925 /// Helper structure to hide all the link to the instruction. In other
2926 /// words, this helps to do as if the instruction was removed.
2927 OperandsHider Hider;
2928
2929 /// Keep track of the uses replaced, if any.
2930 UsesReplacer *Replacer = nullptr;
2931
2932 /// Keep track of instructions removed.
2933 SetOfInstrs &RemovedInsts;
2934
2935 public:
2936 /// Remove all reference of \p Inst and optionally replace all its
2937 /// uses with New.
2938 /// \p RemovedInsts Keep track of the instructions removed by this Action.
2939 /// \pre If !Inst->use_empty(), then New != nullptr
2940 InstructionRemover(Instruction *Inst, SetOfInstrs &RemovedInsts,
2941 Value *New = nullptr)
2942 : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
2943 RemovedInsts(RemovedInsts) {
2944 if (New)
2945 Replacer = new UsesReplacer(Inst, New);
2946 LLVM_DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n")do { } while (false);
2947 RemovedInsts.insert(Inst);
2948 /// The instructions removed here will be freed after completing
2949 /// optimizeBlock() for all blocks as we need to keep track of the
2950 /// removed instructions during promotion.
2951 Inst->removeFromParent();
2952 }
2953
2954 ~InstructionRemover() override { delete Replacer; }
2955
2956 /// Resurrect the instruction and reassign it to the proper uses if
2957 /// new value was provided when build this action.
2958 void undo() override {
2959 LLVM_DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n")do { } while (false);
2960 Inserter.insert(Inst);
2961 if (Replacer)
2962 Replacer->undo();
2963 Hider.undo();
2964 RemovedInsts.erase(Inst);
2965 }
2966 };
2967
2968public:
2969 /// Restoration point.
2970 /// The restoration point is a pointer to an action instead of an iterator
2971 /// because the iterator may be invalidated but not the pointer.
2972 using ConstRestorationPt = const TypePromotionAction *;
2973
2974 TypePromotionTransaction(SetOfInstrs &RemovedInsts)
2975 : RemovedInsts(RemovedInsts) {}
2976
2977 /// Advocate every changes made in that transaction. Return true if any change
2978 /// happen.
2979 bool commit();
2980
2981 /// Undo all the changes made after the given point.
2982 void rollback(ConstRestorationPt Point);
2983
2984 /// Get the current restoration point.
2985 ConstRestorationPt getRestorationPoint() const;
2986
2987 /// \name API for IR modification with state keeping to support rollback.
2988 /// @{
2989 /// Same as Instruction::setOperand.
2990 void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);
2991
2992 /// Same as Instruction::eraseFromParent.
2993 void eraseInstruction(Instruction *Inst, Value *NewVal = nullptr);
2994
2995 /// Same as Value::replaceAllUsesWith.
2996 void replaceAllUsesWith(Instruction *Inst, Value *New);
2997
2998 /// Same as Value::mutateType.
2999 void mutateType(Instruction *Inst, Type *NewTy);
3000
3001 /// Same as IRBuilder::createTrunc.
3002 Value *createTrunc(Instruction *Opnd, Type *Ty);
3003
3004 /// Same as IRBuilder::createSExt.
3005 Value *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);
3006
3007 /// Same as IRBuilder::createZExt.
3008 Value *createZExt(Instruction *Inst, Value *Opnd, Type *Ty);
3009
3010 /// Same as Instruction::moveBefore.
3011 void moveBefore(Instruction *Inst, Instruction *Before);
3012 /// @}
3013
3014private:
3015 /// The ordered list of actions made so far.
3016 SmallVector<std::unique_ptr<TypePromotionAction>, 16> Actions;
3017
3018 using CommitPt = SmallVectorImpl<std::unique_ptr<TypePromotionAction>>::iterator;
3019
3020 SetOfInstrs &RemovedInsts;
3021};
3022
3023} // end anonymous namespace
3024
3025void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
3026 Value *NewVal) {
3027 Actions.push_back(std::make_unique<TypePromotionTransaction::OperandSetter>(
3028 Inst, Idx, NewVal));
3029}
3030
3031void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
3032 Value *NewVal) {
3033 Actions.push_back(
3034 std::make_unique<TypePromotionTransaction::InstructionRemover>(
3035 Inst, RemovedInsts, NewVal));
3036}
3037
3038void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
3039 Value *New) {
3040 Actions.push_back(
3041 std::make_unique<TypePromotionTransaction::UsesReplacer>(Inst, New));
3042}
3043
3044void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
3045 Actions.push_back(
3046 std::make_unique<TypePromotionTransaction::TypeMutator>(Inst, NewTy));
3047}
3048
3049Value *TypePromotionTransaction::createTrunc(Instruction *Opnd,
3050 Type *Ty) {
3051 std::unique_ptr<TruncBuilder> Ptr(new TruncBuilder(Opnd, Ty));
3052 Value *Val = Ptr->getBuiltValue();
3053 Actions.push_back(std::move(Ptr));
3054 return Val;
3055}
3056
3057Value *TypePromotionTransaction::createSExt(Instruction *Inst,
3058 Value *Opnd, Type *Ty) {
3059 std::unique_ptr<SExtBuilder> Ptr(new SExtBuilder(Inst, Opnd, Ty));
3060 Value *Val = Ptr->getBuiltValue();
3061 Actions.push_back(std::move(Ptr));
3062 return Val;
3063}
3064
3065Value *TypePromotionTransaction::createZExt(Instruction *Inst,
3066 Value *Opnd, Type *Ty) {
3067 std::unique_ptr<ZExtBuilder> Ptr(new ZExtBuilder(Inst, Opnd, Ty));
3068 Value *Val = Ptr->getBuiltValue();
3069 Actions.push_back(std::move(Ptr));
3070 return Val;
3071}
3072
3073void TypePromotionTransaction::moveBefore(Instruction *Inst,
3074 Instruction *Before) {
3075 Actions.push_back(
3076 std::make_unique<TypePromotionTransaction::InstructionMoveBefore>(
3077 Inst, Before));
3078}
3079
3080TypePromotionTransaction::ConstRestorationPt
3081TypePromotionTransaction::getRestorationPoint() const {
3082 return !Actions.empty() ? Actions.back().get() : nullptr;
3083}
3084
3085bool TypePromotionTransaction::commit() {
3086 for (std::unique_ptr<TypePromotionAction> &Action : Actions)
3087 Action->commit();
3088 bool Modified = !Actions.empty();
3089 Actions.clear();
3090 return Modified;
3091}
3092
3093void TypePromotionTransaction::rollback(
3094 TypePromotionTransaction::ConstRestorationPt Point) {
3095 while (!Actions.empty() && Point != Actions.back().get()) {
3096 std::unique_ptr<TypePromotionAction> Curr = Actions.pop_back_val();
3097 Curr->undo();
3098 }
3099}
3100
3101namespace {
3102
3103/// A helper class for matching addressing modes.
3104///
3105/// This encapsulates the logic for matching the target-legal addressing modes.
3106class AddressingModeMatcher {
3107 SmallVectorImpl<Instruction*> &AddrModeInsts;
3108 const TargetLowering &TLI;
3109 const TargetRegisterInfo &TRI;
3110 const DataLayout &DL;
3111 const LoopInfo &LI;
3112 const std::function<const DominatorTree &()> getDTFn;
3113
3114 /// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
3115 /// the memory instruction that we're computing this address for.
3116 Type *AccessTy;
3117 unsigned AddrSpace;
3118 Instruction *MemoryInst;
3119
3120 /// This is the addressing mode that we're building up. This is
3121 /// part of the return value of this addressing mode matching stuff.
3122 ExtAddrMode &AddrMode;
3123
3124 /// The instructions inserted by other CodeGenPrepare optimizations.
3125 const SetOfInstrs &InsertedInsts;
3126
3127 /// A map from the instructions to their type before promotion.
3128 InstrToOrigTy &PromotedInsts;
3129
3130 /// The ongoing transaction where every action should be registered.
3131 TypePromotionTransaction &TPT;
3132
3133 // A GEP which has too large offset to be folded into the addressing mode.
3134 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP;
3135
3136 /// This is set to true when we should not do profitability checks.
3137 /// When true, IsProfitableToFoldIntoAddressingMode always returns true.
3138 bool IgnoreProfitability;
3139
3140 /// True if we are optimizing for size.
3141 bool OptSize;
3142
3143 ProfileSummaryInfo *PSI;
3144 BlockFrequencyInfo *BFI;
3145
3146 AddressingModeMatcher(
3147 SmallVectorImpl<Instruction *> &AMI, const TargetLowering &TLI,
3148 const TargetRegisterInfo &TRI, const LoopInfo &LI,
3149 const std::function<const DominatorTree &()> getDTFn,
3150 Type *AT, unsigned AS, Instruction *MI, ExtAddrMode &AM,
3151 const SetOfInstrs &InsertedInsts, InstrToOrigTy &PromotedInsts,
3152 TypePromotionTransaction &TPT,
3153 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
3154 bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI)
3155 : AddrModeInsts(AMI), TLI(TLI), TRI(TRI),
3156 DL(MI->getModule()->getDataLayout()), LI(LI), getDTFn(getDTFn),
3157 AccessTy(AT), AddrSpace(AS), MemoryInst(MI), AddrMode(AM),
3158 InsertedInsts(InsertedInsts), PromotedInsts(PromotedInsts), TPT(TPT),
3159 LargeOffsetGEP(LargeOffsetGEP), OptSize(OptSize), PSI(PSI), BFI(BFI) {
3160 IgnoreProfitability = false;
3161 }
3162
3163public:
3164 /// Find the maximal addressing mode that a load/store of V can fold,
3165 /// give an access type of AccessTy. This returns a list of involved
3166 /// instructions in AddrModeInsts.
3167 /// \p InsertedInsts The instructions inserted by other CodeGenPrepare
3168 /// optimizations.
3169 /// \p PromotedInsts maps the instructions to their type before promotion.
3170 /// \p The ongoing transaction where every action should be registered.
3171 static ExtAddrMode
3172 Match(Value *V, Type *AccessTy, unsigned AS, Instruction *MemoryInst,
3173 SmallVectorImpl<Instruction *> &AddrModeInsts,
3174 const TargetLowering &TLI, const LoopInfo &LI,
3175 const std::function<const DominatorTree &()> getDTFn,
3176 const TargetRegisterInfo &TRI, const SetOfInstrs &InsertedInsts,
3177 InstrToOrigTy &PromotedInsts, TypePromotionTransaction &TPT,
3178 std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
3179 bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) {
3180 ExtAddrMode Result;
3181
3182 bool Success = AddressingModeMatcher(
3183 AddrModeInsts, TLI, TRI, LI, getDTFn, AccessTy, AS, MemoryInst, Result,
3184 InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI,
3185 BFI).matchAddr(V, 0);
3186 (void)Success; assert(Success && "Couldn't select *anything*?")(static_cast<void> (0));
3187 return Result;
3188 }
3189
3190private:
3191 bool matchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
3192 bool matchAddr(Value *Addr, unsigned Depth);
3193 bool matchOperationAddr(User *AddrInst, unsigned Opcode, unsigned Depth,
3194 bool *MovedAway = nullptr);
3195 bool isProfitableToFoldIntoAddressingMode(Instruction *I,
3196 ExtAddrMode &AMBefore,
3197 ExtAddrMode &AMAfter);
3198 bool valueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
3199 bool isPromotionProfitable(unsigned NewCost, unsigned OldCost,
3200 Value *PromotedOperand) const;
3201};
3202
3203class PhiNodeSet;
3204
3205/// An iterator for PhiNodeSet.
3206class PhiNodeSetIterator {
3207 PhiNodeSet * const Set;
3208 size_t CurrentIndex = 0;
3209
3210public:
3211 /// The constructor. Start should point to either a valid element, or be equal
3212 /// to the size of the underlying SmallVector of the PhiNodeSet.
3213 PhiNodeSetIterator(PhiNodeSet * const Set, size_t Start);
3214 PHINode * operator*() const;
3215 PhiNodeSetIterator& operator++();
3216 bool operator==(const PhiNodeSetIterator &RHS) const;
3217 bool operator!=(const PhiNodeSetIterator &RHS) const;
3218};
3219
3220/// Keeps a set of PHINodes.
3221///
3222/// This is a minimal set implementation for a specific use case:
3223/// It is very fast when there are very few elements, but also provides good
3224/// performance when there are many. It is similar to SmallPtrSet, but also
3225/// provides iteration by insertion order, which is deterministic and stable
3226/// across runs. It is also similar to SmallSetVector, but provides removing
3227/// elements in O(1) time. This is achieved by not actually removing the element
3228/// from the underlying vector, so comes at the cost of using more memory, but
3229/// that is fine, since PhiNodeSets are used as short lived objects.
3230class PhiNodeSet {
3231 friend class PhiNodeSetIterator;
3232
3233 using MapType = SmallDenseMap<PHINode *, size_t, 32>;
3234 using iterator = PhiNodeSetIterator;
3235
3236 /// Keeps the elements in the order of their insertion in the underlying
3237 /// vector. To achieve constant time removal, it never deletes any element.
3238 SmallVector<PHINode *, 32> NodeList;
3239
3240 /// Keeps the elements in the underlying set implementation. This (and not the
3241 /// NodeList defined above) is the source of truth on whether an element
3242 /// is actually in the collection.
3243 MapType NodeMap;
3244
3245 /// Points to the first valid (not deleted) element when the set is not empty
3246 /// and the value is not zero. Equals to the size of the underlying vector
3247 /// when the set is empty. When the value is 0, as in the beginning, the
3248 /// first element may or may not be valid.
3249 size_t FirstValidElement = 0;
3250
3251public:
3252 /// Inserts a new element to the collection.
3253 /// \returns true if the element is actually added, i.e. was not in the
3254 /// collection before the operation.
3255 bool insert(PHINode *Ptr) {
3256 if (NodeMap.insert(std::make_pair(Ptr, NodeList.size())).second) {
3257 NodeList.push_back(Ptr);
3258 return true;
3259 }
3260 return false;
3261 }
3262
3263 /// Removes the element from the collection.
3264 /// \returns whether the element is actually removed, i.e. was in the
3265 /// collection before the operation.
3266 bool erase(PHINode *Ptr) {
3267 if (NodeMap.erase(Ptr)) {
3268 SkipRemovedElements(FirstValidElement);
3269 return true;
3270 }
3271 return false;
3272 }
3273
3274 /// Removes all elements and clears the collection.
3275 void clear() {
3276 NodeMap.clear();
3277 NodeList.clear();
3278 FirstValidElement = 0;
3279 }
3280
3281 /// \returns an iterator that will iterate the elements in the order of
3282 /// insertion.
3283 iterator begin() {
3284 if (FirstValidElement == 0)
3285 SkipRemovedElements(FirstValidElement);
3286 return PhiNodeSetIterator(this, FirstValidElement);
3287 }
3288
3289 /// \returns an iterator that points to the end of the collection.
3290 iterator end() { return PhiNodeSetIterator(this, NodeList.size()); }
3291
3292 /// Returns the number of elements in the collection.
3293 size_t size() const {
3294 return NodeMap.size();
3295 }
3296
3297 /// \returns 1 if the given element is in the collection, and 0 if otherwise.
3298 size_t count(PHINode *Ptr) const {
3299 return NodeMap.count(Ptr);
3300 }
3301
3302private:
3303 /// Updates the CurrentIndex so that it will point to a valid element.
3304 ///
3305 /// If the element of NodeList at CurrentIndex is valid, it does not
3306 /// change it. If there are no more valid elements, it updates CurrentIndex
3307 /// to point to the end of the NodeList.
3308 void SkipRemovedElements(size_t &CurrentIndex) {
3309 while (CurrentIndex < NodeList.size()) {
3310 auto it = NodeMap.find(NodeList[CurrentIndex]);
3311 // If the element has been deleted and added again later, NodeMap will
3312 // point to a different index, so CurrentIndex will still be invalid.
3313 if (it != NodeMap.end() && it->second == CurrentIndex)
3314 break;
3315 ++CurrentIndex;
3316 }
3317 }
3318};
3319
3320PhiNodeSetIterator::PhiNodeSetIterator(PhiNodeSet *const Set, size_t Start)
3321 : Set(Set), CurrentIndex(Start) {}
3322
3323PHINode * PhiNodeSetIterator::operator*() const {
3324 assert(CurrentIndex < Set->NodeList.size() &&(static_cast<void> (0))
3325 "PhiNodeSet access out of range")(static_cast<void> (0));
3326 return Set->NodeList[CurrentIndex];
3327}
3328
3329PhiNodeSetIterator& PhiNodeSetIterator::operator++() {
3330 assert(CurrentIndex < Set->NodeList.size() &&(static_cast<void> (0))
3331 "PhiNodeSet access out of range")(static_cast<void> (0));
3332 ++CurrentIndex;
3333 Set->SkipRemovedElements(CurrentIndex);
3334 return *this;
3335}
3336
3337bool PhiNodeSetIterator::operator==(const PhiNodeSetIterator &RHS) const {
3338 return CurrentIndex == RHS.CurrentIndex;
3339}
3340
3341bool PhiNodeSetIterator::operator!=(const PhiNodeSetIterator &RHS) const {
3342 return !((*this) == RHS);
3343}
3344
3345/// Keep track of simplification of Phi nodes.
3346/// Accept the set of all phi nodes and erase phi node from this set
3347/// if it is simplified.
3348class SimplificationTracker {
3349 DenseMap<Value *, Value *> Storage;
3350 const SimplifyQuery &SQ;
3351 // Tracks newly created Phi nodes. The elements are iterated by insertion
3352 // order.
3353 PhiNodeSet AllPhiNodes;
3354 // Tracks newly created Select nodes.
3355 SmallPtrSet<SelectInst *, 32> AllSelectNodes;
3356
3357public:
3358 SimplificationTracker(const SimplifyQuery &sq)
3359 : SQ(sq) {}
3360
3361 Value *Get(Value *V) {
3362 do {
3363 auto SV = Storage.find(V);
3364 if (SV == Storage.end())
3365 return V;
3366 V = SV->second;
3367 } while (true);
3368 }
3369
3370 Value *Simplify(Value *Val) {
3371 SmallVector<Value *, 32> WorkList;
3372 SmallPtrSet<Value *, 32> Visited;
3373 WorkList.push_back(Val);
3374 while (!WorkList.empty()) {
3375 auto *P = WorkList.pop_back_val();
3376 if (!Visited.insert(P).second)
3377 continue;
3378 if (auto *PI = dyn_cast<Instruction>(P))
3379 if (Value *V = SimplifyInstruction(cast<Instruction>(PI), SQ)) {
3380 for (auto *U : PI->users())
3381 WorkList.push_back(cast<Value>(U));
3382 Put(PI, V);
3383 PI->replaceAllUsesWith(V);
3384 if (auto *PHI = dyn_cast<PHINode>(PI))
3385 AllPhiNodes.erase(PHI);
3386 if (auto *Select = dyn_cast<SelectInst>(PI))
3387 AllSelectNodes.erase(Select);
3388 PI->eraseFromParent();
3389 }
3390 }
3391 return Get(Val);
3392 }
3393
3394 void Put(Value *From, Value *To) {
3395 Storage.insert({ From, To });
3396 }
3397
3398 void ReplacePhi(PHINode *From, PHINode *To) {
3399 Value* OldReplacement = Get(From);
3400 while (OldReplacement != From) {
3401 From = To;
3402 To = dyn_cast<PHINode>(OldReplacement);
3403 OldReplacement = Get(From);
3404 }
3405 assert(To && Get(To) == To && "Replacement PHI node is already replaced.")(static_cast<void> (0));
3406 Put(From, To);
3407 From->replaceAllUsesWith(To);
3408 AllPhiNodes.erase(From);
3409 From->eraseFromParent();
3410 }
3411
3412 PhiNodeSet& newPhiNodes() { return AllPhiNodes; }
3413
3414 void insertNewPhi(PHINode *PN) { AllPhiNodes.insert(PN); }
3415
3416 void insertNewSelect(SelectInst *SI) { AllSelectNodes.insert(SI); }
3417
3418 unsigned countNewPhiNodes() const { return AllPhiNodes.size(); }
3419
3420 unsigned countNewSelectNodes() const { return AllSelectNodes.size(); }
3421
3422 void destroyNewNodes(Type *CommonType) {
3423 // For safe erasing, replace the uses with dummy value first.
3424 auto *Dummy = UndefValue::get(CommonType);
3425 for (auto *I : AllPhiNodes) {
3426 I->replaceAllUsesWith(Dummy);
3427 I->eraseFromParent();
3428 }
3429 AllPhiNodes.clear();
3430 for (auto *I : AllSelectNodes) {
3431 I->replaceAllUsesWith(Dummy);
3432 I->eraseFromParent();
3433 }
3434 AllSelectNodes.clear();
3435 }
3436};
3437
3438/// A helper class for combining addressing modes.
3439class AddressingModeCombiner {
3440 typedef DenseMap<Value *, Value *> FoldAddrToValueMapping;
3441 typedef std::pair<PHINode *, PHINode *> PHIPair;
3442
3443private:
3444 /// The addressing modes we've collected.
3445 SmallVector<ExtAddrMode, 16> AddrModes;
3446
3447 /// The field in which the AddrModes differ, when we have more than one.
3448 ExtAddrMode::FieldName DifferentField = ExtAddrMode::NoField;
3449
3450 /// Are the AddrModes that we have all just equal to their original values?
3451 bool AllAddrModesTrivial = true;
3452
3453 /// Common Type for all different fields in addressing modes.
3454 Type *CommonType;
3455
3456 /// SimplifyQuery for simplifyInstruction utility.
3457 const SimplifyQuery &SQ;
3458
3459 /// Original Address.
3460 Value *Original;
3461
3462public:
3463 AddressingModeCombiner(const SimplifyQuery &_SQ, Value *OriginalValue)
3464 : CommonType(nullptr), SQ(_SQ), Original(OriginalValue) {}
3465
3466 /// Get the combined AddrMode
3467 const ExtAddrMode &getAddrMode() const {
3468 return AddrModes[0];
3469 }
3470
3471 /// Add a new AddrMode if it's compatible with the AddrModes we already
3472 /// have.
3473 /// \return True iff we succeeded in doing so.
3474 bool addNewAddrMode(ExtAddrMode &NewAddrMode) {
3475 // Take note of if we have any non-trivial AddrModes, as we need to detect
3476 // when all AddrModes are trivial as then we would introduce a phi or select
3477 // which just duplicates what's already there.
3478 AllAddrModesTrivial = AllAddrModesTrivial && NewAddrMode.isTrivial();
3479
3480 // If this is the first addrmode then everything is fine.
3481 if (AddrModes.empty()) {
3482 AddrModes.emplace_back(NewAddrMode);
3483 return true;
3484 }
3485
3486 // Figure out how different this is from the other address modes, which we
3487 // can do just by comparing against the first one given that we only care
3488 // about the cumulative difference.
3489 ExtAddrMode::FieldName ThisDifferentField =
3490 AddrModes[0].compare(NewAddrMode);
3491 if (DifferentField == ExtAddrMode::NoField)
3492 DifferentField = ThisDifferentField;
3493 else if (DifferentField != ThisDifferentField)
3494 DifferentField = ExtAddrMode::MultipleFields;
3495
3496 // If NewAddrMode differs in more than one dimension we cannot handle it.
3497 bool CanHandle = DifferentField != ExtAddrMode::MultipleFields;
3498
3499 // If Scale Field is different then we reject.
3500 CanHandle = CanHandle && DifferentField != ExtAddrMode::ScaleField;
3501
3502 // We also must reject the case when base offset is different and
3503 // scale reg is not null, we cannot handle this case due to merge of
3504 // different offsets will be used as ScaleReg.
3505 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseOffsField ||
3506 !NewAddrMode.ScaledReg);
3507
3508 // We also must reject the case when GV is different and BaseReg installed
3509 // due to we want to use base reg as a merge of GV values.
3510 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseGVField ||
3511 !NewAddrMode.HasBaseReg);
3512
3513 // Even if NewAddMode is the same we still need to collect it due to
3514 // original value is different. And later we will need all original values
3515 // as anchors during finding the common Phi node.
3516 if (CanHandle)
3517 AddrModes.emplace_back(NewAddrMode);
3518 else
3519 AddrModes.clear();
3520
3521 return CanHandle;
3522 }
3523
3524 /// Combine the addressing modes we've collected into a single
3525 /// addressing mode.
3526 /// \return True iff we successfully combined them or we only had one so
3527 /// didn't need to combine them anyway.
3528 bool combineAddrModes() {
3529 // If we have no AddrModes then they can't be combined.
3530 if (AddrModes.size() == 0)
3531 return false;
3532
3533 // A single AddrMode can trivially be combined.
3534 if (AddrModes.size() == 1 || DifferentField == ExtAddrMode::NoField)
3535 return true;
3536
3537 // If the AddrModes we collected are all just equal to the value they are
3538 // derived from then combining them wouldn't do anything useful.
3539 if (AllAddrModesTrivial)
3540 return false;
3541
3542 if (!addrModeCombiningAllowed())
3543 return false;
3544
3545 // Build a map between <original value, basic block where we saw it> to
3546 // value of base register.
3547 // Bail out if there is no common type.
3548 FoldAddrToValueMapping Map;
3549 if (!initializeMap(Map))
3550 return false;
3551
3552 Value *CommonValue = findCommon(Map);
3553 if (CommonValue)
3554 AddrModes[0].SetCombinedField(DifferentField, CommonValue, AddrModes);
3555 return CommonValue != nullptr;
3556 }
3557
3558private:
3559 /// Initialize Map with anchor values. For address seen
3560 /// we set the value of different field saw in this address.
3561 /// At the same time we find a common type for different field we will
3562 /// use to create new Phi/Select nodes. Keep it in CommonType field.
3563 /// Return false if there is no common type found.
3564 bool initializeMap(FoldAddrToValueMapping &Map) {
3565 // Keep track of keys where the value is null. We will need to replace it
3566 // with constant null when we know the common type.
3567 SmallVector<Value *, 2> NullValue;
3568 Type *IntPtrTy = SQ.DL.getIntPtrType(AddrModes[0].OriginalValue->getType());
3569 for (auto &AM : AddrModes) {
3570 Value *DV = AM.GetFieldAsValue(DifferentField, IntPtrTy);
3571 if (DV) {
3572 auto *Type = DV->getType();
3573 if (CommonType && CommonType != Type)
3574 return false;
3575 CommonType = Type;
3576 Map[AM.OriginalValue] = DV;
3577 } else {
3578 NullValue.push_back(AM.OriginalValue);
3579 }
3580 }
3581 assert(CommonType && "At least one non-null value must be!")(static_cast<void> (0));
3582 for (auto *V : NullValue)
3583 Map[V] = Constant::getNullValue(CommonType);
3584 return true;
3585 }
3586
3587 /// We have mapping between value A and other value B where B was a field in
3588 /// addressing mode represented by A. Also we have an original value C
3589 /// representing an address we start with. Traversing from C through phi and
3590 /// selects we ended up with A's in a map. This utility function tries to find
3591 /// a value V which is a field in addressing mode C and traversing through phi
3592 /// nodes and selects we will end up in corresponded values B in a map.
3593 /// The utility will create a new Phi/Selects if needed.
3594 // The simple example looks as follows:
3595 // BB1:
3596 // p1 = b1 + 40
3597 // br cond BB2, BB3
3598 // BB2:
3599 // p2 = b2 + 40
3600 // br BB3
3601 // BB3:
3602 // p = phi [p1, BB1], [p2, BB2]
3603 // v = load p
3604 // Map is
3605 // p1 -> b1
3606 // p2 -> b2
3607 // Request is
3608 // p -> ?
3609 // The function tries to find or build phi [b1, BB1], [b2, BB2] in BB3.
3610 Value *findCommon(FoldAddrToValueMapping &Map) {
3611 // Tracks the simplification of newly created phi nodes. The reason we use
3612 // this mapping is because we will add new created Phi nodes in AddrToBase.
3613 // Simplification of Phi nodes is recursive, so some Phi node may
3614 // be simplified after we added it to AddrToBase. In reality this
3615 // simplification is possible only if original phi/selects were not
3616 // simplified yet.
3617 // Using this mapping we can find the current value in AddrToBase.
3618 SimplificationTracker ST(SQ);
3619
3620 // First step, DFS to create PHI nodes for all intermediate blocks.
3621 // Also fill traverse order for the second step.
3622 SmallVector<Value *, 32> TraverseOrder;
3623 InsertPlaceholders(Map, TraverseOrder, ST);
3624
3625 // Second Step, fill new nodes by merged values and simplify if possible.
3626 FillPlaceholders(Map, TraverseOrder, ST);
3627
3628 if (!AddrSinkNewSelects && ST.countNewSelectNodes() > 0) {
3629 ST.destroyNewNodes(CommonType);
3630 return nullptr;
3631 }
3632
3633 // Now we'd like to match New Phi nodes to existed ones.
3634 unsigned PhiNotMatchedCount = 0;
3635 if (!MatchPhiSet(ST, AddrSinkNewPhis, PhiNotMatchedCount)) {
3636 ST.destroyNewNodes(CommonType);
3637 return nullptr;
3638 }
3639
3640 auto *Result = ST.Get(Map.find(Original)->second);
3641 if (Result) {
3642 NumMemoryInstsPhiCreated += ST.countNewPhiNodes() + PhiNotMatchedCount;
3643 NumMemoryInstsSelectCreated += ST.countNewSelectNodes();
3644 }
3645 return Result;
3646 }
3647
3648 /// Try to match PHI node to Candidate.
3649 /// Matcher tracks the matched Phi nodes.
3650 bool MatchPhiNode(PHINode *PHI, PHINode *Candidate,
3651 SmallSetVector<PHIPair, 8> &Matcher,
3652 PhiNodeSet &PhiNodesToMatch) {
3653 SmallVector<PHIPair, 8> WorkList;
3654 Matcher.insert({ PHI, Candidate });
3655 SmallSet<PHINode *, 8> MatchedPHIs;
3656 MatchedPHIs.insert(PHI);
3657 WorkList.push_back({ PHI, Candidate });
3658 SmallSet<PHIPair, 8> Visited;
3659 while (!WorkList.empty()) {
3660 auto Item = WorkList.pop_back_val();
3661 if (!Visited.insert(Item).second)
3662 continue;
3663 // We iterate over all incoming values to Phi to compare them.
3664 // If values are different and both of them Phi and the first one is a
3665 // Phi we added (subject to match) and both of them is in the same basic
3666 // block then we can match our pair if values match. So we state that
3667 // these values match and add it to work list to verify that.
3668 for (auto B : Item.first->blocks()) {
3669 Value *FirstValue = Item.first->getIncomingValueForBlock(B);
3670 Value *SecondValue = Item.second->getIncomingValueForBlock(B);
3671 if (FirstValue == SecondValue)
3672 continue;
3673
3674 PHINode *FirstPhi = dyn_cast<PHINode>(FirstValue);
3675 PHINode *SecondPhi = dyn_cast<PHINode>(SecondValue);
3676
3677 // One of them is not Phi or
3678 // The first one is not Phi node from the set we'd like to match or
3679 // Phi nodes from different basic blocks then
3680 // we will not be able to match.
3681 if (!FirstPhi || !SecondPhi || !PhiNodesToMatch.count(FirstPhi) ||
3682 FirstPhi->getParent() != SecondPhi->getParent())
3683 return false;
3684
3685 // If we already matched them then continue.
3686 if (Matcher.count({ FirstPhi, SecondPhi }))
3687 continue;
3688 // So the values are different and does not match. So we need them to
3689 // match. (But we register no more than one match per PHI node, so that
3690 // we won't later try to replace them twice.)
3691 if (MatchedPHIs.insert(FirstPhi).second)
3692 Matcher.insert({ FirstPhi, SecondPhi });
3693 // But me must check it.
3694 WorkList.push_back({ FirstPhi, SecondPhi });
3695 }
3696 }
3697 return true;
3698 }
3699
3700 /// For the given set of PHI nodes (in the SimplificationTracker) try
3701 /// to find their equivalents.
3702 /// Returns false if this matching fails and creation of new Phi is disabled.
3703 bool MatchPhiSet(SimplificationTracker &ST, bool AllowNewPhiNodes,
3704 unsigned &PhiNotMatchedCount) {
3705 // Matched and PhiNodesToMatch iterate their elements in a deterministic
3706 // order, so the replacements (ReplacePhi) are also done in a deterministic
3707 // order.
3708 SmallSetVector<PHIPair, 8> Matched;
3709 SmallPtrSet<PHINode *, 8> WillNotMatch;
3710 PhiNodeSet &PhiNodesToMatch = ST.newPhiNodes();
3711 while (PhiNodesToMatch.size()) {
3712 PHINode *PHI = *PhiNodesToMatch.begin();
3713
3714 // Add us, if no Phi nodes in the basic block we do not match.
3715 WillNotMatch.clear();
3716 WillNotMatch.insert(PHI);
3717
3718 // Traverse all Phis until we found equivalent or fail to do that.
3719 bool IsMatched = false;
3720 for (auto &P : PHI->getParent()->phis()) {
3721 // Skip new Phi nodes.
3722 if (PhiNodesToMatch.count(&P))
3723 continue;
3724 if ((IsMatched = MatchPhiNode(PHI, &P, Matched, PhiNodesToMatch)))
3725 break;
3726 // If it does not match, collect all Phi nodes from matcher.
3727 // if we end up with no match, them all these Phi nodes will not match
3728 // later.
3729 for (auto M : Matched)
3730 WillNotMatch.insert(M.first);
3731 Matched.clear();
3732 }
3733 if (IsMatched) {
3734 // Replace all matched values and erase them.
3735 for (auto MV : Matched)
3736 ST.ReplacePhi(MV.first, MV.second);
3737 Matched.clear();
3738 continue;
3739 }
3740 // If we are not allowed to create new nodes then bail out.
3741 if (!AllowNewPhiNodes)
3742 return false;
3743 // Just remove all seen values in matcher. They will not match anything.
3744 PhiNotMatchedCount += WillNotMatch.size();
3745 for (auto *P : WillNotMatch)
3746 PhiNodesToMatch.erase(P);
3747 }
3748 return true;
3749 }
3750 /// Fill the placeholders with values from predecessors and simplify them.
3751 void FillPlaceholders(FoldAddrToValueMapping &Map,
3752 SmallVectorImpl<Value *> &TraverseOrder,
3753 SimplificationTracker &ST) {
3754 while (!TraverseOrder.empty()) {
3755 Value *Current = TraverseOrder.pop_back_val();
3756 assert(Map.find(Current) != Map.end() && "No node to fill!!!")(static_cast<void> (0));
3757 Value *V = Map[Current];
3758
3759 if (SelectInst *Select = dyn_cast<SelectInst>(V)) {
3760 // CurrentValue also must be Select.
3761 auto *CurrentSelect = cast<SelectInst>(Current);
3762 auto *TrueValue = CurrentSelect->getTrueValue();
3763 assert(Map.find(TrueValue) != Map.end() && "No True Value!")(static_cast<void> (0));
3764 Select->setTrueValue(ST.Get(Map[TrueValue]));
3765 auto *FalseValue = CurrentSelect->getFalseValue();
3766 assert(Map.find(FalseValue) != Map.end() && "No False Value!")(static_cast<void> (0));
3767 Select->setFalseValue(ST.Get(Map[FalseValue]));
3768 } else {
3769 // Must be a Phi node then.
3770 auto *PHI = cast<PHINode>(V);
3771 // Fill the Phi node with values from predecessors.
3772 for (auto *B : predecessors(PHI->getParent())) {
3773 Value *PV = cast<PHINode>(Current)->getIncomingValueForBlock(B);
3774 assert(Map.find(PV) != Map.end() && "No predecessor Value!")(static_cast<void> (0));
3775 PHI->addIncoming(ST.Get(Map[PV]), B);
3776 }
3777 }
3778 Map[Current] = ST.Simplify(V);
3779 }
3780 }
3781
3782 /// Starting from original value recursively iterates over def-use chain up to
3783 /// known ending values represented in a map. For each traversed phi/select
3784 /// inserts a placeholder Phi or Select.
3785 /// Reports all new created Phi/Select nodes by adding them to set.
3786 /// Also reports and order in what values have been traversed.
3787 void InsertPlaceholders(FoldAddrToValueMapping &Map,
3788 SmallVectorImpl<Value *> &TraverseOrder,
3789 SimplificationTracker &ST) {
3790 SmallVector<Value *, 32> Worklist;
3791 assert((isa<PHINode>(Original) || isa<SelectInst>(Original)) &&(static_cast<void> (0))
3792 "Address must be a Phi or Select node")(static_cast<void> (0));
3793 auto *Dummy = UndefValue::get(CommonType);
3794 Worklist.push_back(Original);
3795 while (!Worklist.empty()) {
3796 Value *Current = Worklist.pop_back_val();
3797 // if it is already visited or it is an ending value then skip it.
3798 if (Map.find(Current) != Map.end())
3799 continue;
3800 TraverseOrder.push_back(Current);
3801
3802 // CurrentValue must be a Phi node or select. All others must be covered
3803 // by anchors.
3804 if (SelectInst *CurrentSelect = dyn_cast<SelectInst>(Current)) {
3805 // Is it OK to get metadata from OrigSelect?!
3806 // Create a Select placeholder with dummy value.
3807 SelectInst *Select = SelectInst::Create(
3808 CurrentSelect->getCondition(), Dummy, Dummy,
3809 CurrentSelect->getName(), CurrentSelect, CurrentSelect);
3810 Map[Current] = Select;
3811 ST.insertNewSelect(Select);
3812 // We are interested in True and False values.
3813 Worklist.push_back(CurrentSelect->getTrueValue());
3814 Worklist.push_back(CurrentSelect->getFalseValue());
3815 } else {
3816 // It must be a Phi node then.
3817 PHINode *CurrentPhi = cast<PHINode>(Current);
3818 unsigned PredCount = CurrentPhi->getNumIncomingValues();
3819 PHINode *PHI =
3820 PHINode::Create(CommonType, PredCount, "sunk_phi", CurrentPhi);
3821 Map[Current] = PHI;
3822 ST.insertNewPhi(PHI);
3823 append_range(Worklist, CurrentPhi->incoming_values());
3824 }
3825 }
3826 }
3827
3828 bool addrModeCombiningAllowed() {
3829 if (DisableComplexAddrModes)
3830 return false;
3831 switch (DifferentField) {
3832 default:
3833 return false;
3834 case ExtAddrMode::BaseRegField:
3835 return AddrSinkCombineBaseReg;
3836 case ExtAddrMode::BaseGVField:
3837 return AddrSinkCombineBaseGV;
3838 case ExtAddrMode::BaseOffsField:
3839 return AddrSinkCombineBaseOffs;
3840 case ExtAddrMode::ScaledRegField:
3841 return AddrSinkCombineScaledReg;
3842 }
3843 }
3844};
3845} // end anonymous namespace
3846
3847/// Try adding ScaleReg*Scale to the current addressing mode.
3848/// Return true and update AddrMode if this addr mode is legal for the target,
3849/// false if not.
3850bool AddressingModeMatcher::matchScaledValue(Value *ScaleReg, int64_t Scale,
3851 unsigned Depth) {
3852 // If Scale is 1, then this is the same as adding ScaleReg to the addressing
3853 // mode. Just process that directly.
3854 if (Scale == 1)
3855 return matchAddr(ScaleReg, Depth);
3856
3857 // If the scale is 0, it takes nothing to add this.
3858 if (Scale == 0)
3859 return true;
3860
3861 // If we already have a scale of this value, we can add to it, otherwise, we
3862 // need an available scale field.
3863 if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
3864 return false;
3865
3866 ExtAddrMode TestAddrMode = AddrMode;
3867
3868 // Add scale to turn X*4+X*3 -> X*7. This could also do things like
3869 // [A+B + A*7] -> [B+A*8].
3870 TestAddrMode.Scale += Scale;
3871 TestAddrMode.ScaledReg = ScaleReg;
3872
3873 // If the new address isn't legal, bail out.
3874 if (!TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace))
3875 return false;
3876
3877 // It was legal, so commit it.
3878 AddrMode = TestAddrMode;
3879
3880 // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
3881 // to see if ScaleReg is actually X+C. If so, we can turn this into adding
3882 // X*Scale + C*Scale to addr mode. If we found available IV increment, do not
3883 // go any further: we can reuse it and cannot eliminate it.
3884 ConstantInt *CI = nullptr; Value *AddLHS = nullptr;
3885 if (isa<Instruction>(ScaleReg) && // not a constant expr.
3886 match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI))) &&
3887 !isIVIncrement(ScaleReg, &LI) && CI->getValue().isSignedIntN(64)) {
3888 TestAddrMode.InBounds = false;
3889 TestAddrMode.ScaledReg = AddLHS;
3890 TestAddrMode.BaseOffs += CI->getSExtValue() * TestAddrMode.Scale;
3891
3892 // If this addressing mode is legal, commit it and remember that we folded
3893 // this instruction.
3894 if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace)) {
3895 AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
3896 AddrMode = TestAddrMode;
3897 return true;
3898 }
3899 // Restore status quo.
3900 TestAddrMode = AddrMode;
3901 }
3902
3903 // If this is an add recurrence with a constant step, return the increment
3904 // instruction and the canonicalized step.
3905 auto GetConstantStep = [this](const Value * V)
3906 ->Optional<std::pair<Instruction *, APInt> > {
3907 auto *PN = dyn_cast<PHINode>(V);
3908 if (!PN)
3909 return None;
3910 auto IVInc = getIVIncrement(PN, &LI);
3911 if (!IVInc)
3912 return None;
3913 // TODO: The result of the intrinsics above is two-compliment. However when
3914 // IV inc is expressed as add or sub, iv.next is potentially a poison value.
3915 // If it has nuw or nsw flags, we need to make sure that these flags are
3916 // inferrable at the point of memory instruction. Otherwise we are replacing
3917 // well-defined two-compliment computation with poison. Currently, to avoid
3918 // potentially complex analysis needed to prove this, we reject such cases.
3919 if (auto *OIVInc = dyn_cast<OverflowingBinaryOperator>(IVInc->first))
3920 if (OIVInc->hasNoSignedWrap() || OIVInc->hasNoUnsignedWrap())
3921 return None;
3922 if (auto *ConstantStep = dyn_cast<ConstantInt>(IVInc->second))
3923 return std::make_pair(IVInc->first, ConstantStep->getValue());
3924 return None;
3925 };
3926
3927 // Try to account for the following special case:
3928 // 1. ScaleReg is an inductive variable;
3929 // 2. We use it with non-zero offset;
3930 // 3. IV's increment is available at the point of memory instruction.
3931 //
3932 // In this case, we may reuse the IV increment instead of the IV Phi to
3933 // achieve the following advantages:
3934 // 1. If IV step matches the offset, we will have no need in the offset;
3935 // 2. Even if they don't match, we will reduce the overlap of living IV
3936 // and IV increment, that will potentially lead to better register
3937 // assignment.
3938 if (AddrMode.BaseOffs) {
3939 if (auto IVStep = GetConstantStep(ScaleReg)) {
3940 Instruction *IVInc = IVStep->first;
3941 // The following assert is important to ensure a lack of infinite loops.
3942 // This transforms is (intentionally) the inverse of the one just above.
3943 // If they don't agree on the definition of an increment, we'd alternate
3944 // back and forth indefinitely.
3945 assert(isIVIncrement(IVInc, &LI) && "implied by GetConstantStep")(static_cast<void> (0));
3946 APInt Step = IVStep->second;
3947 APInt Offset = Step * AddrMode.Scale;
3948 if (Offset.isSignedIntN(64)) {
3949 TestAddrMode.InBounds = false;
3950 TestAddrMode.ScaledReg = IVInc;
3951 TestAddrMode.BaseOffs -= Offset.getLimitedValue();
3952 // If this addressing mode is legal, commit it..
3953 // (Note that we defer the (expensive) domtree base legality check
3954 // to the very last possible point.)
3955 if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace) &&
3956 getDTFn().dominates(IVInc, MemoryInst)) {
3957 AddrModeInsts.push_back(cast<Instruction>(IVInc));
3958 AddrMode = TestAddrMode;
3959 return true;
3960 }
3961 // Restore status quo.
3962 TestAddrMode = AddrMode;
3963 }
3964 }
3965 }
3966
3967 // Otherwise, just return what we have.
3968 return true;
3969}
3970
3971/// This is a little filter, which returns true if an addressing computation
3972/// involving I might be folded into a load/store accessing it.
3973/// This doesn't need to be perfect, but needs to accept at least
3974/// the set of instructions that MatchOperationAddr can.
3975static bool MightBeFoldableInst(Instruction *I) {
3976 switch (I->getOpcode()) {
3977 case Instruction::BitCast:
3978 case Instruction::AddrSpaceCast:
3979 // Don't touch identity bitcasts.
3980 if (I->getType() == I->getOperand(0)->getType())
3981 return false;
3982 return I->getType()->isIntOrPtrTy();
3983 case Instruction::PtrToInt:
3984 // PtrToInt is always a noop, as we know that the int type is pointer sized.
3985 return true;
3986 case Instruction::IntToPtr:
3987 // We know the input is intptr_t, so this is foldable.
3988 return true;
3989 case Instruction::Add:
3990 return true;
3991 case Instruction::Mul:
3992 case Instruction::Shl:
3993 // Can only handle X*C and X << C.
3994 return isa<ConstantInt>(I->getOperand(1));
3995 case Instruction::GetElementPtr:
3996 return true;
3997 default:
3998 return false;
3999 }
4000}
4001
4002/// Check whether or not \p Val is a legal instruction for \p TLI.
4003/// \note \p Val is assumed to be the product of some type promotion.
4004/// Therefore if \p Val has an undefined state in \p TLI, this is assumed
4005/// to be legal, as the non-promoted value would have had the same state.
4006static bool isPromotedInstructionLegal(const TargetLowering &TLI,
4007 const DataLayout &DL, Value *Val) {
4008 Instruction *PromotedInst = dyn_cast<Instruction>(Val);
4009 if (!PromotedInst)
4010 return false;
4011 int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
4012 // If the ISDOpcode is undefined, it was undefined before the promotion.
4013 if (!ISDOpcode)
4014 return true;
4015 // Otherwise, check if the promoted instruction is legal or not.
4016 return TLI.isOperationLegalOrCustom(
4017 ISDOpcode, TLI.getValueType(DL, PromotedInst->getType()));
4018}
4019
4020namespace {
4021
4022/// Hepler class to perform type promotion.
4023class TypePromotionHelper {
4024 /// Utility function to add a promoted instruction \p ExtOpnd to
4025 /// \p PromotedInsts and record the type of extension we have seen.
4026 static void addPromotedInst(InstrToOrigTy &PromotedInsts,
4027 Instruction *ExtOpnd,
4028 bool IsSExt) {
4029 ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
4030 InstrToOrigTy::iterator It = PromotedInsts.find(ExtOpnd);
4031 if (It != PromotedInsts.end()) {
4032 // If the new extension is same as original, the information in
4033 // PromotedInsts[ExtOpnd] is still correct.
4034 if (It->second.getInt() == ExtTy)
4035 return;
4036
4037 // Now the new extension is different from old extension, we make
4038 // the type information invalid by setting extension type to
4039 // BothExtension.
4040 ExtTy = BothExtension;
4041 }
4042 PromotedInsts[ExtOpnd] = TypeIsSExt(ExtOpnd->getType(), ExtTy);
4043 }
4044
4045 /// Utility function to query the original type of instruction \p Opnd
4046 /// with a matched extension type. If the extension doesn't match, we
4047 /// cannot use the information we had on the original type.
4048 /// BothExtension doesn't match any extension type.
4049 static const Type *getOrigType(const InstrToOrigTy &PromotedInsts,
4050 Instruction *Opnd,
4051 bool IsSExt) {
4052 ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
4053 InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
4054 if (It != PromotedInsts.end() && It->second.getInt() == ExtTy)
4055 return It->second.getPointer();
4056 return nullptr;
4057 }
4058
4059 /// Utility function to check whether or not a sign or zero extension
4060 /// of \p Inst with \p ConsideredExtType can be moved through \p Inst by
4061 /// either using the operands of \p Inst or promoting \p Inst.
4062 /// The type of the extension is defined by \p IsSExt.
4063 /// In other words, check if:
4064 /// ext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredExtType.
4065 /// #1 Promotion applies:
4066 /// ConsideredExtType Inst (ext opnd1 to ConsideredExtType, ...).
4067 /// #2 Operand reuses:
4068 /// ext opnd1 to ConsideredExtType.
4069 /// \p PromotedInsts maps the instructions to their type before promotion.
4070 static bool canGetThrough(const Instruction *Inst, Type *ConsideredExtType,
4071 const InstrToOrigTy &PromotedInsts, bool IsSExt);
4072
4073 /// Utility function to determine if \p OpIdx should be promoted when
4074 /// promoting \p Inst.
4075 static bool shouldExtOperand(const Instruction *Inst, int OpIdx) {
4076 return !(isa<SelectInst>(Inst) && OpIdx == 0);
4077 }
4078
4079 /// Utility function to promote the operand of \p Ext when this
4080 /// operand is a promotable trunc or sext or zext.
4081 /// \p PromotedInsts maps the instructions to their type before promotion.
4082 /// \p CreatedInstsCost[out] contains the cost of all instructions
4083 /// created to promote the operand of Ext.
4084 /// Newly added extensions are inserted in \p Exts.
4085 /// Newly added truncates are inserted in \p Truncs.
4086 /// Should never be called directly.
4087 /// \return The promoted value which is used instead of Ext.
4088 static Value *promoteOperandForTruncAndAnyExt(
4089 Instruction *Ext, TypePromotionTransaction &TPT,
4090 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4091 SmallVectorImpl<Instruction *> *Exts,
4092 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI);
4093
4094 /// Utility function to promote the operand of \p Ext when this
4095 /// operand is promotable and is not a supported trunc or sext.
4096 /// \p PromotedInsts maps the instructions to their type before promotion.
4097 /// \p CreatedInstsCost[out] contains the cost of all the instructions
4098 /// created to promote the operand of Ext.
4099 /// Newly added extensions are inserted in \p Exts.
4100 /// Newly added truncates are inserted in \p Truncs.
4101 /// Should never be called directly.
4102 /// \return The promoted value which is used instead of Ext.
4103 static Value *promoteOperandForOther(Instruction *Ext,
4104 TypePromotionTransaction &TPT,
4105 InstrToOrigTy &PromotedInsts,
4106 unsigned &CreatedInstsCost,
4107 SmallVectorImpl<Instruction *> *Exts,
4108 SmallVectorImpl<Instruction *> *Truncs,
4109 const TargetLowering &TLI, bool IsSExt);
4110
4111 /// \see promoteOperandForOther.
4112 static Value *signExtendOperandForOther(
4113 Instruction *Ext, TypePromotionTransaction &TPT,
4114 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4115 SmallVectorImpl<Instruction *> *Exts,
4116 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
4117 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
4118 Exts, Truncs, TLI, true);
4119 }
4120
4121 /// \see promoteOperandForOther.
4122 static Value *zeroExtendOperandForOther(
4123 Instruction *Ext, TypePromotionTransaction &TPT,
4124 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4125 SmallVectorImpl<Instruction *> *Exts,
4126 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
4127 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
4128 Exts, Truncs, TLI, false);
4129 }
4130
4131public:
4132 /// Type for the utility function that promotes the operand of Ext.
4133 using Action = Value *(*)(Instruction *Ext, TypePromotionTransaction &TPT,
4134 InstrToOrigTy &PromotedInsts,
4135 unsigned &CreatedInstsCost,
4136 SmallVectorImpl<Instruction *> *Exts,
4137 SmallVectorImpl<Instruction *> *Truncs,
4138 const TargetLowering &TLI);
4139
4140 /// Given a sign/zero extend instruction \p Ext, return the appropriate
4141 /// action to promote the operand of \p Ext instead of using Ext.
4142 /// \return NULL if no promotable action is possible with the current
4143 /// sign extension.
4144 /// \p InsertedInsts keeps track of all the instructions inserted by the
4145 /// other CodeGenPrepare optimizations. This information is important
4146 /// because we do not want to promote these instructions as CodeGenPrepare
4147 /// will reinsert them later. Thus creating an infinite loop: create/remove.
4148 /// \p PromotedInsts maps the instructions to their type before promotion.
4149 static Action getAction(Instruction *Ext, const SetOfInstrs &InsertedInsts,
4150 const TargetLowering &TLI,
4151 const InstrToOrigTy &PromotedInsts);
4152};
4153
4154} // end anonymous namespace
4155
4156bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
4157 Type *ConsideredExtType,
4158 const InstrToOrigTy &PromotedInsts,
4159 bool IsSExt) {
4160 // The promotion helper does not know how to deal with vector types yet.
4161 // To be able to fix that, we would need to fix the places where we
4162 // statically extend, e.g., constants and such.
4163 if (Inst->getType()->isVectorTy())
4164 return false;
4165
4166 // We can always get through zext.
4167 if (isa<ZExtInst>(Inst))
4168 return true;
4169
4170 // sext(sext) is ok too.
4171 if (IsSExt && isa<SExtInst>(Inst))
4172 return true;
4173
4174 // We can get through binary operator, if it is legal. In other words, the
4175 // binary operator must have a nuw or nsw flag.
4176 const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst);
4177 if (isa_and_nonnull<OverflowingBinaryOperator>(BinOp) &&
4178 ((!IsSExt && BinOp->hasNoUnsignedWrap()) ||
4179 (IsSExt && BinOp->hasNoSignedWrap())))
4180 return true;
4181
4182 // ext(and(opnd, cst)) --> and(ext(opnd), ext(cst))
4183 if ((Inst->getOpcode() == Instruction::And ||
4184 Inst->getOpcode() == Instruction::Or))
4185 return true;
4186
4187 // ext(xor(opnd, cst)) --> xor(ext(opnd), ext(cst))
4188 if (Inst->getOpcode() == Instruction::Xor) {
4189 const ConstantInt *Cst = dyn_cast<ConstantInt>(Inst->getOperand(1));
4190 // Make sure it is not a NOT.
4191 if (Cst && !Cst->getValue().isAllOnesValue())
4192 return true;
4193 }
4194
4195 // zext(shrl(opnd, cst)) --> shrl(zext(opnd), zext(cst))
4196 // It may change a poisoned value into a regular value, like
4197 // zext i32 (shrl i8 %val, 12) --> shrl i32 (zext i8 %val), 12
4198 // poisoned value regular value
4199 // It should be OK since undef covers valid value.
4200 if (Inst->getOpcode() == Instruction::LShr && !IsSExt)
4201 return true;
4202
4203 // and(ext(shl(opnd, cst)), cst) --> and(shl(ext(opnd), ext(cst)), cst)
4204 // It may change a poisoned value into a regular value, like
4205 // zext i32 (shl i8 %val, 12) --> shl i32 (zext i8 %val), 12
4206 // poisoned value regular value
4207 // It should be OK since undef covers valid value.
4208 if (Inst->getOpcode() == Instruction::Shl && Inst->hasOneUse()) {
4209 const auto *ExtInst = cast<const Instruction>(*Inst->user_begin());
4210 if (ExtInst->hasOneUse()) {
4211 const auto *AndInst = dyn_cast<const Instruction>(*ExtInst->user_begin());
4212 if (AndInst && AndInst->getOpcode() == Instruction::And) {
4213 const auto *Cst = dyn_cast<ConstantInt>(AndInst->getOperand(1));
4214 if (Cst &&
4215 Cst->getValue().isIntN(Inst->getType()->getIntegerBitWidth()))
4216 return true;
4217 }
4218 }
4219 }
4220
4221 // Check if we can do the following simplification.
4222 // ext(trunc(opnd)) --> ext(opnd)
4223 if (!isa<TruncInst>(Inst))
4224 return false;
4225
4226 Value *OpndVal = Inst->getOperand(0);
4227 // Check if we can use this operand in the extension.
4228 // If the type is larger than the result type of the extension, we cannot.
4229 if (!OpndVal->getType()->isIntegerTy() ||
4230 OpndVal->getType()->getIntegerBitWidth() >
4231 ConsideredExtType->getIntegerBitWidth())
4232 return false;
4233
4234 // If the operand of the truncate is not an instruction, we will not have
4235 // any information on the dropped bits.
4236 // (Actually we could for constant but it is not worth the extra logic).
4237 Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
4238 if (!Opnd)
4239 return false;
4240
4241 // Check if the source of the type is narrow enough.
4242 // I.e., check that trunc just drops extended bits of the same kind of
4243 // the extension.
4244 // #1 get the type of the operand and check the kind of the extended bits.
4245 const Type *OpndType = getOrigType(PromotedInsts, Opnd, IsSExt);
4246 if (OpndType)
4247 ;
4248 else if ((IsSExt && isa<SExtInst>(Opnd)) || (!IsSExt && isa<ZExtInst>(Opnd)))
4249 OpndType = Opnd->getOperand(0)->getType();
4250 else
4251 return false;
4252
4253 // #2 check that the truncate just drops extended bits.
4254 return Inst->getType()->getIntegerBitWidth() >=
4255 OpndType->getIntegerBitWidth();
4256}
4257
4258TypePromotionHelper::Action TypePromotionHelper::getAction(
4259 Instruction *Ext, const SetOfInstrs &InsertedInsts,
4260 const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
4261 assert((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&(static_cast<void> (0))
4262 "Unexpected instruction type")(static_cast<void> (0));
4263 Instruction *ExtOpnd = dyn_cast<Instruction>(Ext->getOperand(0));
4264 Type *ExtTy = Ext->getType();
4265 bool IsSExt = isa<SExtInst>(Ext);
4266 // If the operand of the extension is not an instruction, we cannot
4267 // get through.
4268 // If it, check we can get through.
4269 if (!ExtOpnd || !canGetThrough(ExtOpnd, ExtTy, PromotedInsts, IsSExt))
4270 return nullptr;
4271
4272 // Do not promote if the operand has been added by codegenprepare.
4273 // Otherwise, it means we are undoing an optimization that is likely to be
4274 // redone, thus causing potential infinite loop.
4275 if (isa<TruncInst>(ExtOpnd) && InsertedInsts.count(ExtOpnd))
4276 return nullptr;
4277
4278 // SExt or Trunc instructions.
4279 // Return the related handler.
4280 if (isa<SExtInst>(ExtOpnd) || isa<TruncInst>(ExtOpnd) ||
4281 isa<ZExtInst>(ExtOpnd))
4282 return promoteOperandForTruncAndAnyExt;
4283
4284 // Regular instruction.
4285 // Abort early if we will have to insert non-free instructions.
4286 if (!ExtOpnd->hasOneUse() && !TLI.isTruncateFree(ExtTy, ExtOpnd->getType()))
4287 return nullptr;
4288 return IsSExt ? signExtendOperandForOther : zeroExtendOperandForOther;
4289}
4290
4291Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
4292 Instruction *SExt, TypePromotionTransaction &TPT,
4293 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4294 SmallVectorImpl<Instruction *> *Exts,
4295 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
4296 // By construction, the operand of SExt is an instruction. Otherwise we cannot
4297 // get through it and this method should not be called.
4298 Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
4299 Value *ExtVal = SExt;
4300 bool HasMergedNonFreeExt = false;
4301 if (isa<ZExtInst>(SExtOpnd)) {
4302 // Replace s|zext(zext(opnd))
4303 // => zext(opnd).
4304 HasMergedNonFreeExt = !TLI.isExtFree(SExtOpnd);
4305 Value *ZExt =
4306 TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
4307 TPT.replaceAllUsesWith(SExt, ZExt);
4308 TPT.eraseInstruction(SExt);
4309 ExtVal = ZExt;
4310 } else {
4311 // Replace z|sext(trunc(opnd)) or sext(sext(opnd))
4312 // => z|sext(opnd).
4313 TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
4314 }
4315 CreatedInstsCost = 0;
4316
4317 // Remove dead code.
4318 if (SExtOpnd->use_empty())
4319 TPT.eraseInstruction(SExtOpnd);
4320
4321 // Check if the extension is still needed.
4322 Instruction *ExtInst = dyn_cast<Instruction>(ExtVal);
4323 if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) {
4324 if (ExtInst) {
4325 if (Exts)
4326 Exts->push_back(ExtInst);
4327 CreatedInstsCost = !TLI.isExtFree(ExtInst) && !HasMergedNonFreeExt;
4328 }
4329 return ExtVal;
4330 }
4331
4332 // At this point we have: ext ty opnd to ty.
4333 // Reassign the uses of ExtInst to the opnd and remove ExtInst.
4334 Value *NextVal = ExtInst->getOperand(0);
4335 TPT.eraseInstruction(ExtInst, NextVal);
4336 return NextVal;
4337}
4338
4339Value *TypePromotionHelper::promoteOperandForOther(
4340 Instruction *Ext, TypePromotionTransaction &TPT,
4341 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
4342 SmallVectorImpl<Instruction *> *Exts,
4343 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI,
4344 bool IsSExt) {
4345 // By construction, the operand of Ext is an instruction. Otherwise we cannot
4346 // get through it and this method should not be called.
4347 Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0));
4348 CreatedInstsCost = 0;
4349 if (!ExtOpnd->hasOneUse()) {
4350 // ExtOpnd will be promoted.
4351 // All its uses, but Ext, will need to use a truncated value of the
4352 // promoted version.
4353 // Create the truncate now.
4354 Value *Trunc = TPT.createTrunc(Ext, ExtOpnd->getType());
4355 if (Instruction *ITrunc = dyn_cast<Instruction>(Trunc)) {
4356 // Insert it just after the definition.
4357 ITrunc->moveAfter(ExtOpnd);
4358 if (Truncs)
4359 Truncs->push_back(ITrunc);
4360 }
4361
4362 TPT.replaceAllUsesWith(ExtOpnd, Trunc);
4363 // Restore the operand of Ext (which has been replaced by the previous call
4364 // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
4365 TPT.setOperand(Ext, 0, ExtOpnd);
4366 }
4367
4368 // Get through the Instruction:
4369 // 1. Update its type.
4370 // 2. Replace the uses of Ext by Inst.
4371 // 3. Extend each operand that needs to be extended.
4372
4373 // Remember the original type of the instruction before promotion.
4374 // This is useful to know that the high bits are sign extended bits.
4375 addPromotedInst(PromotedInsts, ExtOpnd, IsSExt);
4376 // Step #1.
4377 TPT.mutateType(ExtOpnd, Ext->getType());
4378 // Step #2.
4379 TPT.replaceAllUsesWith(Ext, ExtOpnd);
4380 // Step #3.
4381 Instruction *ExtForOpnd = Ext;
4382
4383 LLVM_DEBUG(dbgs() << "Propagate Ext to operands\n")do { } while (false);
4384 for (int OpIdx = 0, EndOpIdx = ExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
4385 ++OpIdx) {
4386 LLVM_DEBUG(dbgs() << "Operand:\n" << *(ExtOpnd->getOperand(OpIdx)) << '\n')do { } while (false);
4387 if (ExtOpnd->getOperand(OpIdx)->getType() == Ext->getType() ||
4388 !shouldExtOperand(ExtOpnd, OpIdx)) {
4389 LLVM_DEBUG(dbgs() << "No need to propagate\n")do { } while (false);
4390 continue;
4391 }
4392 // Check if we can statically extend the operand.
4393 Value *Opnd = ExtOpnd->getOperand(OpIdx);
4394 if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
4395 LLVM_DEBUG(dbgs() << "Statically extend\n")do { } while (false);
4396 unsigned BitWidth = Ext->getType()->getIntegerBitWidth();
4397 APInt CstVal = IsSExt ? Cst->getValue().sext(BitWidth)
4398 : Cst->getValue().zext(BitWidth);
4399 TPT.setOperand(ExtOpnd, OpIdx, ConstantInt::get(Ext->getType(), CstVal));
4400 continue;
4401 }
4402 // UndefValue are typed, so we have to statically sign extend them.
4403 if (isa<UndefValue>(Opnd)) {
4404 LLVM_DEBUG(dbgs() << "Statically extend\n")do { } while (false);
4405 TPT.setOperand(ExtOpnd, OpIdx, UndefValue::get(Ext->getType()));
4406 continue;
4407 }
4408
4409 // Otherwise we have to explicitly sign extend the operand.
4410 // Check if Ext was reused to extend an operand.
4411 if (!ExtForOpnd) {
4412 // If yes, create a new one.
4413 LLVM_DEBUG(dbgs() << "More operands to ext\n")do { } while (false);
4414 Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
4415 : TPT.createZExt(Ext, Opnd, Ext->getType());
4416 if (!isa<Instruction>(ValForExtOpnd)) {
4417 TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd);
4418 continue;
4419 }
4420 ExtForOpnd = cast<Instruction>(ValForExtOpnd);
4421 }
4422 if (Exts)
4423 Exts->push_back(ExtForOpnd);
4424 TPT.setOperand(ExtForOpnd, 0, Opnd);
4425
4426 // Move the sign extension before the insertion point.
4427 TPT.moveBefore(ExtForOpnd, ExtOpnd);
4428 TPT.setOperand(ExtOpnd, OpIdx, ExtForOpnd);
4429 CreatedInstsCost += !TLI.isExtFree(ExtForOpnd);
4430 // If more sext are required, new instructions will have to be created.
4431 ExtForOpnd = nullptr;
4432 }
4433 if (ExtForOpnd == Ext) {
4434 LLVM_DEBUG(dbgs() << "Extension is useless now\n")do { } while (false);
4435 TPT.eraseInstruction(Ext);
4436 }
4437 return ExtOpnd;
4438}
4439
4440/// Check whether or not promoting an instruction to a wider type is profitable.
4441/// \p NewCost gives the cost of extension instructions created by the
4442/// promotion.
4443/// \p OldCost gives the cost of extension instructions before the promotion
4444/// plus the number of instructions that have been
4445/// matched in the addressing mode the promotion.
4446/// \p PromotedOperand is the value that has been promoted.
4447/// \return True if the promotion is profitable, false otherwise.
4448bool AddressingModeMatcher::isPromotionProfitable(
4449 unsigned NewCost, unsigned OldCost, Value *PromotedOperand) const {
4450 LLVM_DEBUG(dbgs() << "OldCost: " << OldCost << "\tNewCost: " << NewCostdo { } while (false)
4451 << '\n')do { } while (false);
4452 // The cost of the new extensions is greater than the cost of the
4453 // old extension plus what we folded.
4454 // This is not profitable.
4455 if (NewCost > OldCost)
4456 return false;
4457 if (NewCost < OldCost)
4458 return true;
4459 // The promotion is neutral but it may help folding the sign extension in
4460 // loads for instance.
4461 // Check that we did not create an illegal instruction.
4462 return isPromotedInstructionLegal(TLI, DL, PromotedOperand);
4463}
4464
4465/// Given an instruction or constant expr, see if we can fold the operation
4466/// into the addressing mode. If so, update the addressing mode and return
4467/// true, otherwise return false without modifying AddrMode.
4468/// If \p MovedAway is not NULL, it contains the information of whether or
4469/// not AddrInst has to be folded into the addressing mode on success.
4470/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
4471/// because it has been moved away.
4472/// Thus AddrInst must not be added in the matched instructions.
4473/// This state can happen when AddrInst is a sext, since it may be moved away.
4474/// Therefore, AddrInst may not be valid when MovedAway is true and it must
4475/// not be referenced anymore.
4476bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
4477 unsigned Depth,
4478 bool *MovedAway) {
4479 // Avoid exponential behavior on extremely deep expression trees.
4480 if (Depth >= 5) return false;
4481
4482 // By default, all matched instructions stay in place.
4483 if (MovedAway)
4484 *MovedAway = false;
4485
4486 switch (Opcode) {
4487 case Instruction::PtrToInt:
4488 // PtrToInt is always a noop, as we know that the int type is pointer sized.
4489 return matchAddr(AddrInst->getOperand(0), Depth);
4490 case Instruction::IntToPtr: {
4491 auto AS = AddrInst->getType()->getPointerAddressSpace();
4492 auto PtrTy = MVT::getIntegerVT(DL.getPointerSizeInBits(AS));
4493 // This inttoptr is a no-op if the integer type is pointer sized.
4494 if (TLI.getValueType(DL, AddrInst->getOperand(0)->getType()) == PtrTy)
4495 return matchAddr(AddrInst->getOperand(0), Depth);
4496 return false;
4497 }
4498 case Instruction::BitCast:
4499 // BitCast is always a noop, and we can handle it as long as it is
4500 // int->int or pointer->pointer (we don't want int<->fp or something).
4501 if (AddrInst->getOperand(0)->getType()->isIntOrPtrTy() &&
4502 // Don't touch identity bitcasts. These were probably put here by LSR,
4503 // and we don't want to mess around with them. Assume it knows what it
4504 // is doing.
4505 AddrInst->getOperand(0)->getType() != AddrInst->getType())
4506 return matchAddr(AddrInst->getOperand(0), Depth);
4507 return false;
4508 case Instruction::AddrSpaceCast: {
4509 unsigned SrcAS
4510 = AddrInst->getOperand(0)->getType()->getPointerAddressSpace();
4511 unsigned DestAS = AddrInst->getType()->getPointerAddressSpace();
4512 if (TLI.getTargetMachine().isNoopAddrSpaceCast(SrcAS, DestAS))
4513 return matchAddr(AddrInst->getOperand(0), Depth);
4514 return false;
4515 }
4516 case Instruction::Add: {
4517 // Check to see if we can merge in the RHS then the LHS. If so, we win.
4518 ExtAddrMode BackupAddrMode = AddrMode;
4519 unsigned OldSize = AddrModeInsts.size();
4520 // Start a transaction at this point.
4521 // The LHS may match but not the RHS.
4522 // Therefore, we need a higher level restoration point to undo partially
4523 // matched operation.
4524 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4525 TPT.getRestorationPoint();
4526
4527 AddrMode.InBounds = false;
4528 if (matchAddr(AddrInst->getOperand(1), Depth+1) &&
4529 matchAddr(AddrInst->getOperand(0), Depth+1))
4530 return true;
4531
4532 // Restore the old addr mode info.
4533 AddrMode = BackupAddrMode;
4534 AddrModeInsts.resize(OldSize);
4535 TPT.rollback(LastKnownGood);
4536
4537 // Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
4538 if (matchAddr(AddrInst->getOperand(0), Depth+1) &&
4539 matchAddr(AddrInst->getOperand(1), Depth+1))
4540 return true;
4541
4542 // Otherwise we definitely can't merge the ADD in.
4543 AddrMode = BackupAddrMode;
4544 AddrModeInsts.resize(OldSize);
4545 TPT.rollback(LastKnownGood);
4546 break;
4547 }
4548 //case Instruction::Or:
4549 // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
4550 //break;
4551 case Instruction::Mul:
4552 case Instruction::Shl: {
4553 // Can only handle X*C and X << C.
4554 AddrMode.InBounds = false;
4555 ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
4556 if (!RHS || RHS->getBitWidth() > 64)
4557 return false;
4558 int64_t Scale = RHS->getSExtValue();
4559 if (Opcode == Instruction::Shl)
4560 Scale = 1LL << Scale;
4561
4562 return matchScaledValue(AddrInst->getOperand(0), Scale, Depth);
4563 }
4564 case Instruction::GetElementPtr: {
4565 // Scan the GEP. We check it if it contains constant offsets and at most
4566 // one variable offset.
4567 int VariableOperand = -1;
4568 unsigned VariableScale = 0;
4569
4570 int64_t ConstantOffset = 0;
4571 gep_type_iterator GTI = gep_type_begin(AddrInst);
4572 for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
4573 if (StructType *STy = GTI.getStructTypeOrNull()) {
4574 const StructLayout *SL = DL.getStructLayout(STy);
4575 unsigned Idx =
4576 cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
4577 ConstantOffset += SL->getElementOffset(Idx);
4578 } else {
4579 TypeSize TS = DL.getTypeAllocSize(GTI.getIndexedType());
4580 if (TS.isNonZero()) {
4581 // The optimisations below currently only work for fixed offsets.
4582 if (TS.isScalable())
4583 return false;
4584 int64_t TypeSize = TS.getFixedSize();
4585 if (ConstantInt *CI =
4586 dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
4587 const APInt &CVal = CI->getValue();
4588 if (CVal.getMinSignedBits() <= 64) {
4589 ConstantOffset += CVal.getSExtValue() * TypeSize;
4590 continue;
4591 }
4592 }
4593 // We only allow one variable index at the moment.
4594 if (VariableOperand != -1)
4595 return false;
4596
4597 // Remember the variable index.
4598 VariableOperand = i;
4599 VariableScale = TypeSize;
4600 }
4601 }
4602 }
4603
4604 // A common case is for the GEP to only do a constant offset. In this case,
4605 // just add it to the disp field and check validity.
4606 if (VariableOperand == -1) {
4607 AddrMode.BaseOffs += ConstantOffset;
4608 if (ConstantOffset == 0 ||
4609 TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) {
4610 // Check to see if we can fold the base pointer in too.
4611 if (matchAddr(AddrInst->getOperand(0), Depth+1)) {
4612 if (!cast<GEPOperator>(AddrInst)->isInBounds())
4613 AddrMode.InBounds = false;
4614 return true;
4615 }
4616 } else if (EnableGEPOffsetSplit && isa<GetElementPtrInst>(AddrInst) &&
4617 TLI.shouldConsiderGEPOffsetSplit() && Depth == 0 &&
4618 ConstantOffset > 0) {
4619 // Record GEPs with non-zero offsets as candidates for splitting in the
4620 // event that the offset cannot fit into the r+i addressing mode.
4621 // Simple and common case that only one GEP is used in calculating the
4622 // address for the memory access.
4623 Value *Base = AddrInst->getOperand(0);
4624 auto *BaseI = dyn_cast<Instruction>(Base);
4625 auto *GEP = cast<GetElementPtrInst>(AddrInst);
4626 if (isa<Argument>(Base) || isa<GlobalValue>(Base) ||
4627 (BaseI && !isa<CastInst>(BaseI) &&
4628 !isa<GetElementPtrInst>(BaseI))) {
4629 // Make sure the parent block allows inserting non-PHI instructions
4630 // before the terminator.
4631 BasicBlock *Parent =
4632 BaseI ? BaseI->getParent() : &GEP->getFunction()->getEntryBlock();
4633 if (!Parent->getTerminator()->isEHPad())
4634 LargeOffsetGEP = std::make_pair(GEP, ConstantOffset);
4635 }
4636 }
4637 AddrMode.BaseOffs -= ConstantOffset;
4638 return false;
4639 }
4640
4641 // Save the valid addressing mode in case we can't match.
4642 ExtAddrMode BackupAddrMode = AddrMode;
4643 unsigned OldSize = AddrModeInsts.size();
4644
4645 // See if the scale and offset amount is valid for this target.
4646 AddrMode.BaseOffs += ConstantOffset;
4647 if (!cast<GEPOperator>(AddrInst)->isInBounds())
4648 AddrMode.InBounds = false;
4649
4650 // Match the base operand of the GEP.
4651 if (!matchAddr(AddrInst->getOperand(0), Depth+1)) {
4652 // If it couldn't be matched, just stuff the value in a register.
4653 if (AddrMode.HasBaseReg) {
4654 AddrMode = BackupAddrMode;
4655 AddrModeInsts.resize(OldSize);
4656 return false;
4657 }
4658 AddrMode.HasBaseReg = true;
4659 AddrMode.BaseReg = AddrInst->getOperand(0);
4660 }
4661
4662 // Match the remaining variable portion of the GEP.
4663 if (!matchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
4664 Depth)) {
4665 // If it couldn't be matched, try stuffing the base into a register
4666 // instead of matching it, and retrying the match of the scale.
4667 AddrMode = BackupAddrMode;
4668 AddrModeInsts.resize(OldSize);
4669 if (AddrMode.HasBaseReg)
4670 return false;
4671 AddrMode.HasBaseReg = true;
4672 AddrMode.BaseReg = AddrInst->getOperand(0);
4673 AddrMode.BaseOffs += ConstantOffset;
4674 if (!matchScaledValue(AddrInst->getOperand(VariableOperand),
4675 VariableScale, Depth)) {
4676 // If even that didn't work, bail.
4677 AddrMode = BackupAddrMode;
4678 AddrModeInsts.resize(OldSize);
4679 return false;
4680 }
4681 }
4682
4683 return true;
4684 }
4685 case Instruction::SExt:
4686 case Instruction::ZExt: {
4687 Instruction *Ext = dyn_cast<Instruction>(AddrInst);
4688 if (!Ext)
4689 return false;
4690
4691 // Try to move this ext out of the way of the addressing mode.
4692 // Ask for a method for doing so.
4693 TypePromotionHelper::Action TPH =
4694 TypePromotionHelper::getAction(Ext, InsertedInsts, TLI, PromotedInsts);
4695 if (!TPH)
4696 return false;
4697
4698 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4699 TPT.getRestorationPoint();
4700 unsigned CreatedInstsCost = 0;
4701 unsigned ExtCost = !TLI.isExtFree(Ext);
4702 Value *PromotedOperand =
4703 TPH(Ext, TPT, PromotedInsts, CreatedInstsCost, nullptr, nullptr, TLI);
4704 // SExt has been moved away.
4705 // Thus either it will be rematched later in the recursive calls or it is
4706 // gone. Anyway, we must not fold it into the addressing mode at this point.
4707 // E.g.,
4708 // op = add opnd, 1
4709 // idx = ext op
4710 // addr = gep base, idx
4711 // is now:
4712 // promotedOpnd = ext opnd <- no match here
4713 // op = promoted_add promotedOpnd, 1 <- match (later in recursive calls)
4714 // addr = gep base, op <- match
4715 if (MovedAway)
4716 *MovedAway = true;
4717
4718 assert(PromotedOperand &&(static_cast<void> (0))
4719 "TypePromotionHelper should have filtered out those cases")(static_cast<void> (0));
4720
4721 ExtAddrMode BackupAddrMode = AddrMode;
4722 unsigned OldSize = AddrModeInsts.size();
4723
4724 if (!matchAddr(PromotedOperand, Depth) ||
4725 // The total of the new cost is equal to the cost of the created
4726 // instructions.
4727 // The total of the old cost is equal to the cost of the extension plus
4728 // what we have saved in the addressing mode.
4729 !isPromotionProfitable(CreatedInstsCost,
4730 ExtCost + (AddrModeInsts.size() - OldSize),
4731 PromotedOperand)) {
4732 AddrMode = BackupAddrMode;
4733 AddrModeInsts.resize(OldSize);
4734 LLVM_DEBUG(dbgs() << "Sign extension does not pay off: rollback\n")do { } while (false);
4735 TPT.rollback(LastKnownGood);
4736 return false;
4737 }
4738 return true;
4739 }
4740 }
4741 return false;
4742}
4743
4744/// If we can, try to add the value of 'Addr' into the current addressing mode.
4745/// If Addr can't be added to AddrMode this returns false and leaves AddrMode
4746/// unmodified. This assumes that Addr is either a pointer type or intptr_t
4747/// for the target.
4748///
4749bool AddressingModeMatcher::matchAddr(Value *Addr, unsigned Depth) {
4750 // Start a transaction at this point that we will rollback if the matching
4751 // fails.
4752 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4753 TPT.getRestorationPoint();
4754 if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
4755 if (CI->getValue().isSignedIntN(64)) {
4756 // Fold in immediates if legal for the target.
4757 AddrMode.BaseOffs += CI->getSExtValue();
4758 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4759 return true;
4760 AddrMode.BaseOffs -= CI->getSExtValue();
4761 }
4762 } else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
4763 // If this is a global variable, try to fold it into the addressing mode.
4764 if (!AddrMode.BaseGV) {
4765 AddrMode.BaseGV = GV;
4766 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4767 return true;
4768 AddrMode.BaseGV = nullptr;
4769 }
4770 } else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
4771 ExtAddrMode BackupAddrMode = AddrMode;
4772 unsigned OldSize = AddrModeInsts.size();
4773
4774 // Check to see if it is possible to fold this operation.
4775 bool MovedAway = false;
4776 if (matchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
4777 // This instruction may have been moved away. If so, there is nothing
4778 // to check here.
4779 if (MovedAway)
4780 return true;
4781 // Okay, it's possible to fold this. Check to see if it is actually
4782 // *profitable* to do so. We use a simple cost model to avoid increasing
4783 // register pressure too much.
4784 if (I->hasOneUse() ||
4785 isProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
4786 AddrModeInsts.push_back(I);
4787 return true;
4788 }
4789
4790 // It isn't profitable to do this, roll back.
4791 //cerr << "NOT FOLDING: " << *I;
4792 AddrMode = BackupAddrMode;
4793 AddrModeInsts.resize(OldSize);
4794 TPT.rollback(LastKnownGood);
4795 }
4796 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
4797 if (matchOperationAddr(CE, CE->getOpcode(), Depth))
4798 return true;
4799 TPT.rollback(LastKnownGood);
4800 } else if (isa<ConstantPointerNull>(Addr)) {
4801 // Null pointer gets folded without affecting the addressing mode.
4802 return true;
4803 }
4804
4805 // Worse case, the target should support [reg] addressing modes. :)
4806 if (!AddrMode.HasBaseReg) {
4807 AddrMode.HasBaseReg = true;
4808 AddrMode.BaseReg = Addr;
4809 // Still check for legality in case the target supports [imm] but not [i+r].
4810 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4811 return true;
4812 AddrMode.HasBaseReg = false;
4813 AddrMode.BaseReg = nullptr;
4814 }
4815
4816 // If the base register is already taken, see if we can do [r+r].
4817 if (AddrMode.Scale == 0) {
4818 AddrMode.Scale = 1;
4819 AddrMode.ScaledReg = Addr;
4820 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
4821 return true;
4822 AddrMode.Scale = 0;
4823 AddrMode.ScaledReg = nullptr;
4824 }
4825 // Couldn't match.
4826 TPT.rollback(LastKnownGood);
4827 return false;
4828}
4829
4830/// Check to see if all uses of OpVal by the specified inline asm call are due
4831/// to memory operands. If so, return true, otherwise return false.
4832static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
4833 const TargetLowering &TLI,
4834 const TargetRegisterInfo &TRI) {
4835 const Function *F = CI->getFunction();
4836 TargetLowering::AsmOperandInfoVector TargetConstraints =
4837 TLI.ParseConstraints(F->getParent()->getDataLayout(), &TRI, *CI);
4838
4839 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
4840 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
4841
4842 // Compute the constraint code and ConstraintType to use.
4843 TLI.ComputeConstraintToUse(OpInfo, SDValue());
4844
4845 // If this asm operand is our Value*, and if it isn't an indirect memory
4846 // operand, we can't fold it!
4847 if (OpInfo.CallOperandVal == OpVal &&
4848 (OpInfo.ConstraintType != TargetLowering::C_Memory ||
4849 !OpInfo.isIndirect))
4850 return false;
4851 }
4852
4853 return true;
4854}
4855
4856// Max number of memory uses to look at before aborting the search to conserve
4857// compile time.
4858static constexpr int MaxMemoryUsesToScan = 20;
4859
4860/// Recursively walk all the uses of I until we find a memory use.
4861/// If we find an obviously non-foldable instruction, return true.
4862/// Add the ultimately found memory instructions to MemoryUses.
4863static bool FindAllMemoryUses(
4864 Instruction *I,
4865 SmallVectorImpl<std::pair<Instruction *, unsigned>> &MemoryUses,
4866 SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetLowering &TLI,
4867 const TargetRegisterInfo &TRI, bool OptSize, ProfileSummaryInfo *PSI,
4868 BlockFrequencyInfo *BFI, int SeenInsts = 0) {
4869 // If we already considered this instruction, we're done.
4870 if (!ConsideredInsts.insert(I).second)
4871 return false;
4872
4873 // If this is an obviously unfoldable instruction, bail out.
4874 if (!MightBeFoldableInst(I))
4875 return true;
4876
4877 // Loop over all the uses, recursively processing them.
4878 for (Use &U : I->uses()) {
4879 // Conservatively return true if we're seeing a large number or a deep chain
4880 // of users. This avoids excessive compilation times in pathological cases.
4881 if (SeenInsts++ >= MaxMemoryUsesToScan)
4882 return true;
4883
4884 Instruction *UserI = cast<Instruction>(U.getUser());
4885 if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) {
4886 MemoryUses.push_back(std::make_pair(LI, U.getOperandNo()));
4887 continue;
4888 }
4889
4890 if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) {
4891 unsigned opNo = U.getOperandNo();
4892 if (opNo != StoreInst::getPointerOperandIndex())
4893 return true; // Storing addr, not into addr.
4894 MemoryUses.push_back(std::make_pair(SI, opNo));
4895 continue;
4896 }
4897
4898 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(UserI)) {
4899 unsigned opNo = U.getOperandNo();
4900 if (opNo != AtomicRMWInst::getPointerOperandIndex())
4901 return true; // Storing addr, not into addr.
4902 MemoryUses.push_back(std::make_pair(RMW, opNo));
4903 continue;
4904 }
4905
4906 if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(UserI)) {
4907 unsigned opNo = U.getOperandNo();
4908 if (opNo != AtomicCmpXchgInst::getPointerOperandIndex())
4909 return true; // Storing addr, not into addr.
4910 MemoryUses.push_back(std::make_pair(CmpX, opNo));
4911 continue;
4912 }
4913
4914 if (CallInst *CI = dyn_cast<CallInst>(UserI)) {
4915 if (CI->hasFnAttr(Attribute::Cold)) {
4916 // If this is a cold call, we can sink the addressing calculation into
4917 // the cold path. See optimizeCallInst
4918 bool OptForSize = OptSize ||
4919 llvm::shouldOptimizeForSize(CI->getParent(), PSI, BFI);
4920 if (!OptForSize)
4921 continue;
4922 }
4923
4924 InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledOperand());
4925 if (!IA) return true;
4926
4927 // If this is a memory operand, we're cool, otherwise bail out.
4928 if (!IsOperandAMemoryOperand(CI, IA, I, TLI, TRI))
4929 return true;
4930 continue;
4931 }
4932
4933 if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
4934 PSI, BFI, SeenInsts))
4935 return true;
4936 }
4937
4938 return false;
4939}
4940
4941/// Return true if Val is already known to be live at the use site that we're
4942/// folding it into. If so, there is no cost to include it in the addressing
4943/// mode. KnownLive1 and KnownLive2 are two values that we know are live at the
4944/// instruction already.
4945bool AddressingModeMatcher::valueAlreadyLiveAtInst(Value *Val,Value *KnownLive1,
4946 Value *KnownLive2) {
4947 // If Val is either of the known-live values, we know it is live!
4948 if (Val == nullptr || Val == KnownLive1 || Val == KnownLive2)
4949 return true;
4950
4951 // All values other than instructions and arguments (e.g. constants) are live.
4952 if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true;
4953
4954 // If Val is a constant sized alloca in the entry block, it is live, this is
4955 // true because it is just a reference to the stack/frame pointer, which is
4956 // live for the whole function.
4957 if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
4958 if (AI->isStaticAlloca())
4959 return true;
4960
4961 // Check to see if this value is already used in the memory instruction's
4962 // block. If so, it's already live into the block at the very least, so we
4963 // can reasonably fold it.
4964 return Val->isUsedInBasicBlock(MemoryInst->getParent());
4965}
4966
4967/// It is possible for the addressing mode of the machine to fold the specified
4968/// instruction into a load or store that ultimately uses it.
4969/// However, the specified instruction has multiple uses.
4970/// Given this, it may actually increase register pressure to fold it
4971/// into the load. For example, consider this code:
4972///
4973/// X = ...
4974/// Y = X+1
4975/// use(Y) -> nonload/store
4976/// Z = Y+1
4977/// load Z
4978///
4979/// In this case, Y has multiple uses, and can be folded into the load of Z
4980/// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to
4981/// be live at the use(Y) line. If we don't fold Y into load Z, we use one
4982/// fewer register. Since Y can't be folded into "use(Y)" we don't increase the
4983/// number of computations either.
4984///
4985/// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If
4986/// X was live across 'load Z' for other reasons, we actually *would* want to
4987/// fold the addressing mode in the Z case. This would make Y die earlier.
4988bool AddressingModeMatcher::
4989isProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore,
4990 ExtAddrMode &AMAfter) {
4991 if (IgnoreProfitability) return true;
4992
4993 // AMBefore is the addressing mode before this instruction was folded into it,
4994 // and AMAfter is the addressing mode after the instruction was folded. Get
4995 // the set of registers referenced by AMAfter and subtract out those
4996 // referenced by AMBefore: this is the set of values which folding in this
4997 // address extends the lifetime of.
4998 //
4999 // Note that there are only two potential values being referenced here,
5000 // BaseReg and ScaleReg (global addresses are always available, as are any
5001 // folded immediates).
5002 Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;
5003
5004 // If the BaseReg or ScaledReg was referenced by the previous addrmode, their
5005 // lifetime wasn't extended by adding this instruction.
5006 if (valueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
5007 BaseReg = nullptr;
5008 if (valueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
5009 ScaledReg = nullptr;
5010
5011 // If folding this instruction (and it's subexprs) didn't extend any live
5012 // ranges, we're ok with it.
5013 if (!BaseReg && !ScaledReg)
5014 return true;
5015
5016 // If all uses of this instruction can have the address mode sunk into them,
5017 // we can remove the addressing mode and effectively trade one live register
5018 // for another (at worst.) In this context, folding an addressing mode into
5019 // the use is just a particularly nice way of sinking it.
5020 SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
5021 SmallPtrSet<Instruction*, 16> ConsideredInsts;
5022 if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
5023 PSI, BFI))
5024 return false; // Has a non-memory, non-foldable use!
5025
5026 // Now that we know that all uses of this instruction are part of a chain of
5027 // computation involving only operations that could theoretically be folded
5028 // into a memory use, loop over each of these memory operation uses and see
5029 // if they could *actually* fold the instruction. The assumption is that
5030 // addressing modes are cheap and that duplicating the computation involved
5031 // many times is worthwhile, even on a fastpath. For sinking candidates
5032 // (i.e. cold call sites), this serves as a way to prevent excessive code
5033 // growth since most architectures have some reasonable small and fast way to
5034 // compute an effective address. (i.e LEA on x86)
5035 SmallVector<Instruction*, 32> MatchedAddrModeInsts;
5036 for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) {
5037 Instruction *User = MemoryUses[i].first;
5038 unsigned OpNo = MemoryUses[i].second;
5039
5040 // Get the access type of this use. If the use isn't a pointer, we don't
5041 // know what it accesses.
5042 Value *Address = User->getOperand(OpNo);
5043 PointerType *AddrTy = dyn_cast<PointerType>(Address->getType());
5044 if (!AddrTy)
5045 return false;
5046 Type *AddressAccessTy = AddrTy->getElementType();
5047 unsigned AS = AddrTy->getAddressSpace();
5048
5049 // Do a match against the root of this address, ignoring profitability. This
5050 // will tell us if the addressing mode for the memory operation will
5051 // *actually* cover the shared instruction.
5052 ExtAddrMode Result;
5053 std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
5054 0);
5055 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
5056 TPT.getRestorationPoint();
5057 AddressingModeMatcher Matcher(MatchedAddrModeInsts, TLI, TRI, LI, getDTFn,
5058 AddressAccessTy, AS, MemoryInst, Result,
5059 InsertedInsts, PromotedInsts, TPT,
5060 LargeOffsetGEP, OptSize, PSI, BFI);
5061 Matcher.IgnoreProfitability = true;
5062 bool Success = Matcher.matchAddr(Address, 0);
5063 (void)Success; assert(Success && "Couldn't select *anything*?")(static_cast<void> (0));
5064
5065 // The match was to check the profitability, the changes made are not
5066 // part of the original matcher. Therefore, they should be dropped
5067 // otherwise the original matcher will not present the right state.
5068 TPT.rollback(LastKnownGood);
5069
5070 // If the match didn't cover I, then it won't be shared by it.
5071 if (!is_contained(MatchedAddrModeInsts, I))
5072 return false;
5073
5074 MatchedAddrModeInsts.clear();
5075 }
5076
5077 return true;
5078}
5079
5080/// Return true if the specified values are defined in a
5081/// different basic block than BB.
5082static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
5083 if (Instruction *I = dyn_cast<Instruction>(V))
5084 return I->getParent() != BB;
5085 return false;
5086}
5087
5088/// Sink addressing mode computation immediate before MemoryInst if doing so
5089/// can be done without increasing register pressure. The need for the
5090/// register pressure constraint means this can end up being an all or nothing
5091/// decision for all uses of the same addressing computation.
5092///
5093/// Load and Store Instructions often have addressing modes that can do
5094/// significant amounts of computation. As such, instruction selection will try
5095/// to get the load or store to do as much computation as possible for the
5096/// program. The problem is that isel can only see within a single block. As
5097/// such, we sink as much legal addressing mode work into the block as possible.
5098///
5099/// This method is used to optimize both load/store and inline asms with memory
5100/// operands. It's also used to sink addressing computations feeding into cold
5101/// call sites into their (cold) basic block.
5102///
5103/// The motivation for handling sinking into cold blocks is that doing so can
5104/// both enable other address mode sinking (by satisfying the register pressure
5105/// constraint above), and reduce register pressure globally (by removing the
5106/// addressing mode computation from the fast path entirely.).
5107bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
5108 Type *AccessTy, unsigned AddrSpace) {
5109 Value *Repl = Addr;
5110
5111 // Try to collapse single-value PHI nodes. This is necessary to undo
5112 // unprofitable PRE transformations.
5113 SmallVector<Value*, 8> worklist;
5114 SmallPtrSet<Value*, 16> Visited;
5115 worklist.push_back(Addr);
5116
5117 // Use a worklist to iteratively look through PHI and select nodes, and
5118 // ensure that the addressing mode obtained from the non-PHI/select roots of
5119 // the graph are compatible.
5120 bool PhiOrSelectSeen = false;
5121 SmallVector<Instruction*, 16> AddrModeInsts;
5122 const SimplifyQuery SQ(*DL, TLInfo);
5123 AddressingModeCombiner AddrModes(SQ, Addr);
5124 TypePromotionTransaction TPT(RemovedInsts);
5125 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
5126 TPT.getRestorationPoint();
5127 while (!worklist.empty()) {
5128 Value *V = worklist.back();
5129 worklist.pop_back();
5130
5131 // We allow traversing cyclic Phi nodes.
5132 // In case of success after this loop we ensure that traversing through
5133 // Phi nodes ends up with all cases to compute address of the form
5134 // BaseGV + Base + Scale * Index + Offset
5135 // where Scale and Offset are constans and BaseGV, Base and Index
5136 // are exactly the same Values in all cases.
5137 // It means that BaseGV, Scale and Offset dominate our memory instruction
5138 // and have the same value as they had in address computation represented
5139 // as Phi. So we can safely sink address computation to memory instruction.
5140 if (!Visited.insert(V).second)
5141 continue;
5142
5143 // For a PHI node, push all of its incoming values.
5144 if (PHINode *P = dyn_cast<PHINode>(V)) {
5145 append_range(worklist, P->incoming_values());
5146 PhiOrSelectSeen = true;
5147 continue;
5148 }
5149 // Similar for select.
5150 if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
5151 worklist.push_back(SI->getFalseValue());
5152 worklist.push_back(SI->getTrueValue());
5153 PhiOrSelectSeen = true;
5154 continue;
5155 }
5156
5157 // For non-PHIs, determine the addressing mode being computed. Note that
5158 // the result may differ depending on what other uses our candidate
5159 // addressing instructions might have.
5160 AddrModeInsts.clear();
5161 std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
5162 0);
5163 // Defer the query (and possible computation of) the dom tree to point of
5164 // actual use. It's expected that most address matches don't actually need
5165 // the domtree.
5166 auto getDTFn = [MemoryInst, this]() -> const DominatorTree & {
5167 Function *F = MemoryInst->getParent()->getParent();
5168 return this->getDT(*F);
5169 };
5170 ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
5171 V, AccessTy, AddrSpace, MemoryInst, AddrModeInsts, *TLI, *LI, getDTFn,
5172 *TRI, InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI,
5173 BFI.get());
5174
5175 GetElementPtrInst *GEP = LargeOffsetGEP.first;
5176 if (GEP && !NewGEPBases.count(GEP)) {
5177 // If splitting the underlying data structure can reduce the offset of a
5178 // GEP, collect the GEP. Skip the GEPs that are the new bases of
5179 // previously split data structures.
5180 LargeOffsetGEPMap[GEP->getPointerOperand()].push_back(LargeOffsetGEP);
5181 if (LargeOffsetGEPID.find(GEP) == LargeOffsetGEPID.end())
5182 LargeOffsetGEPID[GEP] = LargeOffsetGEPID.size();
5183 }
5184
5185 NewAddrMode.OriginalValue = V;
5186 if (!AddrModes.addNewAddrMode(NewAddrMode))
5187 break;
5188 }
5189
5190 // Try to combine the AddrModes we've collected. If we couldn't collect any,
5191 // or we have multiple but either couldn't combine them or combining them
5192 // wouldn't do anything useful, bail out now.
5193 if (!AddrModes.combineAddrModes()) {
5194 TPT.rollback(LastKnownGood);
5195 return false;
5196 }
5197 bool Modified = TPT.commit();
5198
5199 // Get the combined AddrMode (or the only AddrMode, if we only had one).
5200 ExtAddrMode AddrMode = AddrModes.getAddrMode();
5201
5202 // If all the instructions matched are already in this BB, don't do anything.
5203 // If we saw a Phi node then it is not local definitely, and if we saw a select
5204 // then we want to push the address calculation past it even if it's already
5205 // in this BB.
5206 if (!PhiOrSelectSeen && none_of(AddrModeInsts, [&](Value *V) {
5207 return IsNonLocalValue(V, MemoryInst->getParent());
5208 })) {
5209 LLVM_DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrModedo { } while (false)
5210 << "\n")do { } while (false);
5211 return Modified;
5212 }
5213
5214 // Insert this computation right after this user. Since our caller is
5215 // scanning from the top of the BB to the bottom, reuse of the expr are
5216 // guaranteed to happen later.
5217 IRBuilder<> Builder(MemoryInst);
5218
5219 // Now that we determined the addressing expression we want to use and know
5220 // that we have to sink it into this block. Check to see if we have already
5221 // done this for some other load/store instr in this block. If so, reuse
5222 // the computation. Before attempting reuse, check if the address is valid
5223 // as it may have been erased.
5224
5225 WeakTrackingVH SunkAddrVH = SunkAddrs[Addr];
5226
5227 Value * SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr;
5228 if (SunkAddr) {
5229 LLVM_DEBUG(dbgs() << "CGP: Reusing nonlocal addrmode: " << AddrModedo { } while (false)
5230 << " for " << *MemoryInst << "\n")do { } while (false);
5231 if (SunkAddr->getType() != Addr->getType())
5232 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
5233 } else if (AddrSinkUsingGEPs || (!AddrSinkUsingGEPs.getNumOccurrences() &&
5234 SubtargetInfo->addrSinkUsingGEPs())) {
5235 // By default, we use the GEP-based method when AA is used later. This
5236 // prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
5237 LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { } while (false)
5238 << " for " << *MemoryInst << "\n")do { } while (false);
5239 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
5240 Value *ResultPtr = nullptr, *ResultIndex = nullptr;
5241
5242 // First, find the pointer.
5243 if (AddrMode.BaseReg && AddrMode.BaseReg->getType()->isPointerTy()) {
5244 ResultPtr = AddrMode.BaseReg;
5245 AddrMode.BaseReg = nullptr;
5246 }
5247
5248 if (AddrMode.Scale && AddrMode.ScaledReg->getType()->isPointerTy()) {
5249 // We can't add more than one pointer together, nor can we scale a
5250 // pointer (both of which seem meaningless).
5251 if (ResultPtr || AddrMode.Scale != 1)
5252 return Modified;
5253
5254 ResultPtr = AddrMode.ScaledReg;
5255 AddrMode.Scale = 0;
5256 }
5257
5258 // It is only safe to sign extend the BaseReg if we know that the math
5259 // required to create it did not overflow before we extend it. Since
5260 // the original IR value was tossed in favor of a constant back when
5261 // the AddrMode was created we need to bail out gracefully if widths
5262 // do not match instead of extending it.
5263 //
5264 // (See below for code to add the scale.)
5265 if (AddrMode.Scale) {
5266 Type *ScaledRegTy = AddrMode.ScaledReg->getType();
5267 if (cast<IntegerType>(IntPtrTy)->getBitWidth() >
5268 cast<IntegerType>(ScaledRegTy)->getBitWidth())
5269 return Modified;
5270 }
5271
5272 if (AddrMode.BaseGV) {
5273 if (ResultPtr)
5274 return Modified;
5275
5276 ResultPtr = AddrMode.BaseGV;
5277 }
5278
5279 // If the real base value actually came from an inttoptr, then the matcher
5280 // will look through it and provide only the integer value. In that case,
5281 // use it here.
5282 if (!DL->isNonIntegralPointerType(Addr->getType())) {
5283 if (!ResultPtr && AddrMode.BaseReg) {
5284 ResultPtr = Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(),
5285 "sunkaddr");
5286 AddrMode.BaseReg = nullptr;
5287 } else if (!ResultPtr && AddrMode.Scale == 1) {
5288 ResultPtr = Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(),
5289 "sunkaddr");
5290 AddrMode.Scale = 0;
5291 }
5292 }
5293
5294 if (!ResultPtr &&
5295 !AddrMode.BaseReg && !AddrMode.Scale && !AddrMode.BaseOffs) {
5296 SunkAddr = Constant::getNullValue(Addr->getType());
5297 } else if (!ResultPtr) {
5298 return Modified;
5299 } else {
5300 Type *I8PtrTy =
5301 Builder.getInt8PtrTy(Addr->getType()->getPointerAddressSpace());
5302 Type *I8Ty = Builder.getInt8Ty();
5303
5304 // Start with the base register. Do this first so that subsequent address
5305 // matching finds it last, which will prevent it from trying to match it
5306 // as the scaled value in case it happens to be a mul. That would be
5307 // problematic if we've sunk a different mul for the scale, because then
5308 // we'd end up sinking both muls.
5309 if (AddrMode.BaseReg) {
5310 Value *V = AddrMode.BaseReg;
5311 if (V->getType() != IntPtrTy)
5312 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
5313
5314 ResultIndex = V;
5315 }
5316
5317 // Add the scale value.
5318 if (AddrMode.Scale) {
5319 Value *V = AddrMode.ScaledReg;
5320 if (V->getType() == IntPtrTy) {
5321 // done.
5322 } else {
5323 assert(cast<IntegerType>(IntPtrTy)->getBitWidth() <(static_cast<void> (0))
5324 cast<IntegerType>(V->getType())->getBitWidth() &&(static_cast<void> (0))
5325 "We can't transform if ScaledReg is too narrow")(static_cast<void> (0));
5326 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
5327 }
5328
5329 if (AddrMode.Scale != 1)
5330 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
5331 "sunkaddr");
5332 if (ResultIndex)
5333 ResultIndex = Builder.CreateAdd(ResultIndex, V, "sunkaddr");
5334 else
5335 ResultIndex = V;
5336 }
5337
5338 // Add in the Base Offset if present.
5339 if (AddrMode.BaseOffs) {
5340 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
5341 if (ResultIndex) {
5342 // We need to add this separately from the scale above to help with
5343 // SDAG consecutive load/store merging.
5344 if (ResultPtr->getType() != I8PtrTy)
5345 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
5346 ResultPtr =
5347 AddrMode.InBounds
5348 ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
5349 "sunkaddr")
5350 : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
5351 }
5352
5353 ResultIndex = V;
5354 }
5355
5356 if (!ResultIndex) {
5357 SunkAddr = ResultPtr;
5358 } else {
5359 if (ResultPtr->getType() != I8PtrTy)
5360 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
5361 SunkAddr =
5362 AddrMode.InBounds
5363 ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
5364 "sunkaddr")
5365 : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
5366 }
5367
5368 if (SunkAddr->getType() != Addr->getType())
5369 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
5370 }
5371 } else {
5372 // We'd require a ptrtoint/inttoptr down the line, which we can't do for
5373 // non-integral pointers, so in that case bail out now.
5374 Type *BaseTy = AddrMode.BaseReg ? AddrMode.BaseReg->getType() : nullptr;
5375 Type *ScaleTy = AddrMode.Scale ? AddrMode.ScaledReg->getType() : nullptr;
5376 PointerType *BasePtrTy = dyn_cast_or_null<PointerType>(BaseTy);
5377 PointerType *ScalePtrTy = dyn_cast_or_null<PointerType>(ScaleTy);
5378 if (DL->isNonIntegralPointerType(Addr->getType()) ||
5379 (BasePtrTy && DL->isNonIntegralPointerType(BasePtrTy)) ||
5380 (ScalePtrTy && DL->isNonIntegralPointerType(ScalePtrTy)) ||
5381 (AddrMode.BaseGV &&
5382 DL->isNonIntegralPointerType(AddrMode.BaseGV->getType())))
5383 return Modified;
5384
5385 LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { } while (false)
5386 << " for " << *MemoryInst << "\n")do { } while (false);
5387 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
5388 Value *Result = nullptr;
5389
5390 // Start with the base register. Do this first so that subsequent address
5391 // matching finds it last, which will prevent it from trying to match it
5392 // as the scaled value in case it happens to be a mul. That would be
5393 // problematic if we've sunk a different mul for the scale, because then
5394 // we'd end up sinking both muls.
5395 if (AddrMode.BaseReg) {
5396 Value *V = AddrMode.BaseReg;
5397 if (V->getType()->isPointerTy())
5398 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
5399 if (V->getType() != IntPtrTy)
5400 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
5401 Result = V;
5402 }
5403
5404 // Add the scale value.
5405 if (AddrMode.Scale) {
5406 Value *V = AddrMode.ScaledReg;
5407 if (V->getType() == IntPtrTy) {
5408 // done.
5409 } else if (V->getType()->isPointerTy()) {
5410 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
5411 } else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
5412 cast<IntegerType>(V->getType())->getBitWidth()) {
5413 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
5414 } else {
5415 // It is only safe to sign extend the BaseReg if we know that the math
5416 // required to create it did not overflow before we extend it. Since
5417 // the original IR value was tossed in favor of a constant back when
5418 // the AddrMode was created we need to bail out gracefully if widths
5419 // do not match instead of extending it.
5420 Instruction *I = dyn_cast_or_null<Instruction>(Result);
5421 if (I && (Result != AddrMode.BaseReg))
5422 I->eraseFromParent();
5423 return Modified;
5424 }
5425 if (AddrMode.Scale != 1)
5426 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
5427 "sunkaddr");
5428 if (Result)
5429 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5430 else
5431 Result = V;
5432 }
5433
5434 // Add in the BaseGV if present.
5435 if (AddrMode.BaseGV) {
5436 Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
5437 if (Result)
5438 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5439 else
5440 Result = V;
5441 }
5442
5443 // Add in the Base Offset if present.
5444 if (AddrMode.BaseOffs) {
5445 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
5446 if (Result)
5447 Result = Builder.CreateAdd(Result, V, "sunkaddr");
5448 else
5449 Result = V;
5450 }
5451
5452 if (!Result)
5453 SunkAddr = Constant::getNullValue(Addr->getType());
5454 else
5455 SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr");
5456 }
5457
5458 MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
5459 // Store the newly computed address into the cache. In the case we reused a
5460 // value, this should be idempotent.
5461 SunkAddrs[Addr] = WeakTrackingVH(SunkAddr);
5462
5463 // If we have no uses, recursively delete the value and all dead instructions
5464 // using it.
5465 if (Repl->use_empty()) {
5466 resetIteratorIfInvalidatedWhileCalling(CurInstIterator->getParent(), [&]() {
5467 RecursivelyDeleteTriviallyDeadInstructions(
5468 Repl, TLInfo, nullptr,
5469 [&](Value *V) { removeAllAssertingVHReferences(V); });
5470 });
5471 }
5472 ++NumMemoryInsts;
5473 return true;
5474}
5475
5476/// Rewrite GEP input to gather/scatter to enable SelectionDAGBuilder to find
5477/// a uniform base to use for ISD::MGATHER/MSCATTER. SelectionDAGBuilder can
5478/// only handle a 2 operand GEP in the same basic block or a splat constant
5479/// vector. The 2 operands to the GEP must have a scalar pointer and a vector
5480/// index.
5481///
5482/// If the existing GEP has a vector base pointer that is splat, we can look
5483/// through the splat to find the scalar pointer. If we can't find a scalar
5484/// pointer there's nothing we can do.
5485///
5486/// If we have a GEP with more than 2 indices where the middle indices are all
5487/// zeroes, we can replace it with 2 GEPs where the second has 2 operands.
5488///
5489/// If the final index isn't a vector or is a splat, we can emit a scalar GEP
5490/// followed by a GEP with an all zeroes vector index. This will enable
5491/// SelectionDAGBuilder to use the scalar GEP as the uniform base and have a
5492/// zero index.
5493bool CodeGenPrepare::optimizeGatherScatterInst(Instruction *MemoryInst,
5494 Value *Ptr) {
5495 Value *NewAddr;
5496
5497 if (const auto *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
5498 // Don't optimize GEPs that don't have indices.
5499 if (!GEP->hasIndices())
5500 return false;
5501
5502 // If the GEP and the gather/scatter aren't in the same BB, don't optimize.
5503 // FIXME: We should support this by sinking the GEP.
5504 if (MemoryInst->getParent() != GEP->getParent())
5505 return false;
5506
5507 SmallVector<Value *, 2> Ops(GEP->operands());
5508
5509 bool RewriteGEP = false;
5510
5511 if (Ops[0]->getType()->isVectorTy()) {
5512 Ops[0] = getSplatValue(Ops[0]);
5513 if (!Ops[0])
5514 return false;
5515 RewriteGEP = true;
5516 }
5517
5518 unsigned FinalIndex = Ops.size() - 1;
5519
5520 // Ensure all but the last index is 0.
5521 // FIXME: This isn't strictly required. All that's required is that they are
5522 // all scalars or splats.
5523 for (unsigned i = 1; i < FinalIndex; ++i) {
5524 auto *C = dyn_cast<Constant>(Ops[i]);
5525 if (!C)
5526 return false;
5527 if (isa<VectorType>(C->getType()))
5528 C = C->getSplatValue();
5529 auto *CI = dyn_cast_or_null<ConstantInt>(C);
5530 if (!CI || !CI->isZero())
5531 return false;
5532 // Scalarize the index if needed.
5533 Ops[i] = CI;
5534 }
5535
5536 // Try to scalarize the final index.
5537 if (Ops[FinalIndex]->getType()->isVectorTy()) {
5538 if (Value *V = getSplatValue(Ops[FinalIndex])) {
5539 auto *C = dyn_cast<ConstantInt>(V);
5540 // Don't scalarize all zeros vector.
5541 if (!C || !C->isZero()) {
5542 Ops[FinalIndex] = V;
5543 RewriteGEP = true;
5544 }
5545 }
5546 }
5547
5548 // If we made any changes or the we have extra operands, we need to generate
5549 // new instructions.
5550 if (!RewriteGEP && Ops.size() == 2)
5551 return false;
5552
5553 auto NumElts = cast<VectorType>(Ptr->getType())->getElementCount();
5554
5555 IRBuilder<> Builder(MemoryInst);
5556
5557 Type *SourceTy = GEP->getSourceElementType();
5558 Type *ScalarIndexTy = DL->getIndexType(Ops[0]->getType()->getScalarType());
5559
5560 // If the final index isn't a vector, emit a scalar GEP containing all ops
5561 // and a vector GEP with all zeroes final index.
5562 if (!Ops[FinalIndex]->getType()->isVectorTy()) {
5563 NewAddr = Builder.CreateGEP(SourceTy, Ops[0],
5564 makeArrayRef(Ops).drop_front());
5565 auto *IndexTy = VectorType::get(ScalarIndexTy, NumElts);
5566 auto *SecondTy = GetElementPtrInst::getIndexedType(
5567 SourceTy, makeArrayRef(Ops).drop_front());
5568 NewAddr =
5569 Builder.CreateGEP(SecondTy, NewAddr, Constant::getNullValue(IndexTy));
5570 } else {
5571 Value *Base = Ops[0];
5572 Value *Index = Ops[FinalIndex];
5573
5574 // Create a scalar GEP if there are more than 2 operands.
5575 if (Ops.size() != 2) {
5576 // Replace the last index with 0.
5577 Ops[FinalIndex] = Constant::getNullValue(ScalarIndexTy);
5578 Base = Builder.CreateGEP(SourceTy, Base,
5579 makeArrayRef(Ops).drop_front());
5580 SourceTy = GetElementPtrInst::getIndexedType(
5581 SourceTy, makeArrayRef(Ops).drop_front());
5582 }
5583
5584 // Now create the GEP with scalar pointer and vector index.
5585 NewAddr = Builder.CreateGEP(SourceTy, Base, Index);
5586 }
5587 } else if (!isa<Constant>(Ptr)) {
5588 // Not a GEP, maybe its a splat and we can create a GEP to enable
5589 // SelectionDAGBuilder to use it as a uniform base.
5590 Value *V = getSplatValue(Ptr);
5591 if (!V)
5592 return false;
5593
5594 auto NumElts = cast<VectorType>(Ptr->getType())->getElementCount();
5595
5596 IRBuilder<> Builder(MemoryInst);
5597
5598 // Emit a vector GEP with a scalar pointer and all 0s vector index.
5599 Type *ScalarIndexTy = DL->getIndexType(V->getType()->getScalarType());
5600 auto *IndexTy = VectorType::get(ScalarIndexTy, NumElts);
5601 Type *ScalarTy;
5602 if (cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() ==
5603 Intrinsic::masked_gather) {
5604 ScalarTy = MemoryInst->getType()->getScalarType();
5605 } else {
5606 assert(cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() ==(static_cast<void> (0))
5607 Intrinsic::masked_scatter)(static_cast<void> (0));
5608 ScalarTy = MemoryInst->getOperand(0)->getType()->getScalarType();
5609 }
5610 NewAddr = Builder.CreateGEP(ScalarTy, V, Constant::getNullValue(IndexTy));
5611 } else {
5612 // Constant, SelectionDAGBuilder knows to check if its a splat.
5613 return false;
5614 }
5615
5616 MemoryInst->replaceUsesOfWith(Ptr, NewAddr);
5617
5618 // If we have no uses, recursively delete the value and all dead instructions
5619 // using it.
5620 if (Ptr->use_empty())
5621 RecursivelyDeleteTriviallyDeadInstructions(
5622 Ptr, TLInfo, nullptr,
5623 [&](Value *V) { removeAllAssertingVHReferences(V); });
5624
5625 return true;
5626}
5627
5628/// If there are any memory operands, use OptimizeMemoryInst to sink their
5629/// address computing into the block when possible / profitable.
5630bool CodeGenPrepare::optimizeInlineAsmInst(CallInst *CS) {
5631 bool MadeChange = false;
5632
5633 const TargetRegisterInfo *TRI =
5634 TM->getSubtargetImpl(*CS->getFunction())->getRegisterInfo();
5635 TargetLowering::AsmOperandInfoVector TargetConstraints =
5636 TLI->ParseConstraints(*DL, TRI, *CS);
5637 unsigned ArgNo = 0;
5638 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
5639 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
5640
5641 // Compute the constraint code and ConstraintType to use.
5642 TLI->ComputeConstraintToUse(OpInfo, SDValue());
5643
5644 if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
5645 OpInfo.isIndirect) {
5646 Value *OpVal = CS->getArgOperand(ArgNo++);
5647 MadeChange |= optimizeMemoryInst(CS, OpVal, OpVal->getType(), ~0u);
5648 } else if (OpInfo.Type == InlineAsm::isInput)
5649 ArgNo++;
5650 }
5651
5652 return MadeChange;
5653}
5654
5655/// Check if all the uses of \p Val are equivalent (or free) zero or
5656/// sign extensions.
5657static bool hasSameExtUse(Value *Val, const TargetLowering &TLI) {
5658 assert(!Val->use_empty() && "Input must have at least one use")(static_cast<void> (0));
5659 const Instruction *FirstUser = cast<Instruction>(*Val->user_begin());
5660 bool IsSExt = isa<SExtInst>(FirstUser);
5661 Type *ExtTy = FirstUser->getType();
5662 for (const User *U : Val->users()) {
5663 const Instruction *UI = cast<Instruction>(U);
5664 if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI)))
5665 return false;
5666 Type *CurTy = UI->getType();
5667 // Same input and output types: Same instruction after CSE.
5668 if (CurTy == ExtTy)
5669 continue;
5670
5671 // If IsSExt is true, we are in this situation:
5672 // a = Val
5673 // b = sext ty1 a to ty2
5674 // c = sext ty1 a to ty3
5675 // Assuming ty2 is shorter than ty3, this could be turned into:
5676 // a = Val
5677 // b = sext ty1 a to ty2
5678 // c = sext ty2 b to ty3
5679 // However, the last sext is not free.
5680 if (IsSExt)
5681 return false;
5682
5683 // This is a ZExt, maybe this is free to extend from one type to another.
5684 // In that case, we would not account for a different use.
5685 Type *NarrowTy;
5686 Type *LargeTy;
5687 if (ExtTy->getScalarType()->getIntegerBitWidth() >
5688 CurTy->getScalarType()->getIntegerBitWidth()) {
5689 NarrowTy = CurTy;
5690 LargeTy = ExtTy;
5691 } else {
5692 NarrowTy = ExtTy;
5693 LargeTy = CurTy;
5694 }
5695
5696 if (!TLI.isZExtFree(NarrowTy, LargeTy))
5697 return false;
5698 }
5699 // All uses are the same or can be derived from one another for free.
5700 return true;
5701}
5702
5703/// Try to speculatively promote extensions in \p Exts and continue
5704/// promoting through newly promoted operands recursively as far as doing so is
5705/// profitable. Save extensions profitably moved up, in \p ProfitablyMovedExts.
5706/// When some promotion happened, \p TPT contains the proper state to revert
5707/// them.
5708///
5709/// \return true if some promotion happened, false otherwise.
5710bool CodeGenPrepare::tryToPromoteExts(
5711 TypePromotionTransaction &TPT, const SmallVectorImpl<Instruction *> &Exts,
5712 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
5713 unsigned CreatedInstsCost) {
5714 bool Promoted = false;
5715
5716 // Iterate over all the extensions to try to promote them.
5717 for (auto *I : Exts) {
5718 // Early check if we directly have ext(load).
5719 if (isa<LoadInst>(I->getOperand(0))) {
5720 ProfitablyMovedExts.push_back(I);
5721 continue;
5722 }
5723
5724 // Check whether or not we want to do any promotion. The reason we have
5725 // this check inside the for loop is to catch the case where an extension
5726 // is directly fed by a load because in such case the extension can be moved
5727 // up without any promotion on its operands.
5728 if (!TLI->enableExtLdPromotion() || DisableExtLdPromotion)
5729 return false;
5730
5731 // Get the action to perform the promotion.
5732 TypePromotionHelper::Action TPH =
5733 TypePromotionHelper::getAction(I, InsertedInsts, *TLI, PromotedInsts);
5734 // Check if we can promote.
5735 if (!TPH) {
5736 // Save the current extension as we cannot move up through its operand.
5737 ProfitablyMovedExts.push_back(I);
5738 continue;
5739 }
5740
5741 // Save the current state.
5742 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
5743 TPT.getRestorationPoint();
5744 SmallVector<Instruction *, 4> NewExts;
5745 unsigned NewCreatedInstsCost = 0;
5746 unsigned ExtCost = !TLI->isExtFree(I);
5747 // Promote.
5748 Value *PromotedVal = TPH(I, TPT, PromotedInsts, NewCreatedInstsCost,
5749 &NewExts, nullptr, *TLI);
5750 assert(PromotedVal &&(static_cast<void> (0))
5751 "TypePromotionHelper should have filtered out those cases")(static_cast<void> (0));
5752
5753 // We would be able to merge only one extension in a load.
5754 // Therefore, if we have more than 1 new extension we heuristically
5755 // cut this search path, because it means we degrade the code quality.
5756 // With exactly 2, the transformation is neutral, because we will merge
5757 // one extension but leave one. However, we optimistically keep going,
5758 // because the new extension may be removed too.
5759 long long TotalCreatedInstsCost = CreatedInstsCost + NewCreatedInstsCost;
5760 // FIXME: It would be possible to propagate a negative value instead of
5761 // conservatively ceiling it to 0.
5762 TotalCreatedInstsCost =
5763 std::max((long long)0, (TotalCreatedInstsCost - ExtCost));
5764 if (!StressExtLdPromotion &&
5765 (TotalCreatedInstsCost > 1 ||
5766 !isPromotedInstructionLegal(*TLI, *DL, PromotedVal))) {
5767 // This promotion is not profitable, rollback to the previous state, and
5768 // save the current extension in ProfitablyMovedExts as the latest
5769 // speculative promotion turned out to be unprofitable.
5770 TPT.rollback(LastKnownGood);
5771 ProfitablyMovedExts.push_back(I);
5772 continue;
5773 }
5774 // Continue promoting NewExts as far as doing so is profitable.
5775 SmallVector<Instruction *, 2> NewlyMovedExts;
5776 (void)tryToPromoteExts(TPT, NewExts, NewlyMovedExts, TotalCreatedInstsCost);
5777 bool NewPromoted = false;
5778 for (auto *ExtInst : NewlyMovedExts) {
5779 Instruction *MovedExt = cast<Instruction>(ExtInst);
5780 Value *ExtOperand = MovedExt->getOperand(0);
5781 // If we have reached to a load, we need this extra profitability check
5782 // as it could potentially be merged into an ext(load).
5783 if (isa<LoadInst>(ExtOperand) &&
5784 !(StressExtLdPromotion || NewCreatedInstsCost <= ExtCost ||
5785 (ExtOperand->hasOneUse() || hasSameExtUse(ExtOperand, *TLI))))
5786 continue;
5787
5788 ProfitablyMovedExts.push_back(MovedExt);
5789 NewPromoted = true;
5790 }
5791
5792 // If none of speculative promotions for NewExts is profitable, rollback
5793 // and save the current extension (I) as the last profitable extension.
5794 if (!NewPromoted) {
5795 TPT.rollback(LastKnownGood);
5796 ProfitablyMovedExts.push_back(I);
5797 continue;
5798 }
5799 // The promotion is profitable.
5800 Promoted = true;
5801 }
5802 return Promoted;
5803}
5804
5805/// Merging redundant sexts when one is dominating the other.
5806bool CodeGenPrepare::mergeSExts(Function &F) {
5807 bool Changed = false;
5808 for (auto &Entry : ValToSExtendedUses) {
5809 SExts &Insts = Entry.second;
5810 SExts CurPts;
5811 for (Instruction *Inst : Insts) {
5812 if (RemovedInsts.count(Inst) || !isa<SExtInst>(Inst) ||
5813 Inst->getOperand(0) != Entry.first)
5814 continue;
5815 bool inserted = false;
5816 for (auto &Pt : CurPts) {
5817 if (getDT(F).dominates(Inst, Pt)) {
5818 Pt->replaceAllUsesWith(Inst);
5819 RemovedInsts.insert(Pt);
5820 Pt->removeFromParent();
5821 Pt = Inst;
5822 inserted = true;
5823 Changed = true;
5824 break;
5825 }
5826 if (!getDT(F).dominates(Pt, Inst))
5827 // Give up if we need to merge in a common dominator as the
5828 // experiments show it is not profitable.
5829 continue;
5830 Inst->replaceAllUsesWith(Pt);
5831 RemovedInsts.insert(Inst);
5832 Inst->removeFromParent();
5833 inserted = true;
5834 Changed = true;
5835 break;
5836 }
5837 if (!inserted)
5838 CurPts.push_back(Inst);
5839 }
5840 }
5841 return Changed;
5842}
5843
5844// Splitting large data structures so that the GEPs accessing them can have
5845// smaller offsets so that they can be sunk to the same blocks as their users.
5846// For example, a large struct starting from %base is split into two parts
5847// where the second part starts from %new_base.
5848//
5849// Before:
5850// BB0:
5851// %base =
5852//
5853// BB1:
5854// %gep0 = gep %base, off0
5855// %gep1 = gep %base, off1
5856// %gep2 = gep %base, off2
5857//
5858// BB2:
5859// %load1 = load %gep0
5860// %load2 = load %gep1
5861// %load3 = load %gep2
5862//
5863// After:
5864// BB0:
5865// %base =
5866// %new_base = gep %base, off0
5867//
5868// BB1:
5869// %new_gep0 = %new_base
5870// %new_gep1 = gep %new_base, off1 - off0
5871// %new_gep2 = gep %new_base, off2 - off0
5872//
5873// BB2:
5874// %load1 = load i32, i32* %new_gep0
5875// %load2 = load i32, i32* %new_gep1
5876// %load3 = load i32, i32* %new_gep2
5877//
5878// %new_gep1 and %new_gep2 can be sunk to BB2 now after the splitting because
5879// their offsets are smaller enough to fit into the addressing mode.
5880bool CodeGenPrepare::splitLargeGEPOffsets() {
5881 bool Changed = false;
5882 for (