Bug Summary

File:lib/CodeGen/CodeGenPrepare.cpp
Warning:line 3083, column 41
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name CodeGenPrepare.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-eagerly-assume -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 -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-7/lib/clang/7.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-7~svn326246/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen -I /build/llvm-toolchain-snapshot-7~svn326246/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn326246/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0/backward -internal-isystem /usr/include/clang/7.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-7/lib/clang/7.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-7~svn326246/build-llvm/lib/CodeGen -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-02-28-041547-14988-1 -x c++ /build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp
1//===- CodeGenPrepare.cpp - Prepare a function for code generation --------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This pass munges the code in the input function to better prepare it for
11// SelectionDAG-based code generation. This works around limitations in it's
12// basic-block-at-a-time approach. It should eventually be removed.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/ADT/APInt.h"
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/DenseMap.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/CodeGen/Analysis.h"
35#include "llvm/CodeGen/ISDOpcodes.h"
36#include "llvm/CodeGen/MachineValueType.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/IR/Argument.h"
43#include "llvm/IR/Attributes.h"
44#include "llvm/IR/BasicBlock.h"
45#include "llvm/IR/CallSite.h"
46#include "llvm/IR/Constant.h"
47#include "llvm/IR/Constants.h"
48#include "llvm/IR/DataLayout.h"
49#include "llvm/IR/DerivedTypes.h"
50#include "llvm/IR/Dominators.h"
51#include "llvm/IR/Function.h"
52#include "llvm/IR/GetElementPtrTypeIterator.h"
53#include "llvm/IR/GlobalValue.h"
54#include "llvm/IR/GlobalVariable.h"
55#include "llvm/IR/IRBuilder.h"
56#include "llvm/IR/InlineAsm.h"
57#include "llvm/IR/InstrTypes.h"
58#include "llvm/IR/Instruction.h"
59#include "llvm/IR/Instructions.h"
60#include "llvm/IR/IntrinsicInst.h"
61#include "llvm/IR/Intrinsics.h"
62#include "llvm/IR/LLVMContext.h"
63#include "llvm/IR/MDBuilder.h"
64#include "llvm/IR/Module.h"
65#include "llvm/IR/Operator.h"
66#include "llvm/IR/PatternMatch.h"
67#include "llvm/IR/Statepoint.h"
68#include "llvm/IR/Type.h"
69#include "llvm/IR/Use.h"
70#include "llvm/IR/User.h"
71#include "llvm/IR/Value.h"
72#include "llvm/IR/ValueHandle.h"
73#include "llvm/IR/ValueMap.h"
74#include "llvm/Pass.h"
75#include "llvm/Support/BlockFrequency.h"
76#include "llvm/Support/BranchProbability.h"
77#include "llvm/Support/Casting.h"
78#include "llvm/Support/CommandLine.h"
79#include "llvm/Support/Compiler.h"
80#include "llvm/Support/Debug.h"
81#include "llvm/Support/ErrorHandling.h"
82#include "llvm/Support/MathExtras.h"
83#include "llvm/Support/raw_ostream.h"
84#include "llvm/Target/TargetMachine.h"
85#include "llvm/Target/TargetOptions.h"
86#include "llvm/Transforms/Utils/BasicBlockUtils.h"
87#include "llvm/Transforms/Utils/BypassSlowDivision.h"
88#include "llvm/Transforms/Utils/Local.h"
89#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
90#include <algorithm>
91#include <cassert>
92#include <cstdint>
93#include <iterator>
94#include <limits>
95#include <memory>
96#include <utility>
97#include <vector>
98
99using namespace llvm;
100using namespace llvm::PatternMatch;
101
102#define DEBUG_TYPE"codegenprepare" "codegenprepare"
103
104STATISTIC(NumBlocksElim, "Number of blocks eliminated")static llvm::Statistic NumBlocksElim = {"codegenprepare", "NumBlocksElim"
, "Number of blocks eliminated", {0}, {false}}
;
105STATISTIC(NumPHIsElim, "Number of trivial PHIs eliminated")static llvm::Statistic NumPHIsElim = {"codegenprepare", "NumPHIsElim"
, "Number of trivial PHIs eliminated", {0}, {false}}
;
106STATISTIC(NumGEPsElim, "Number of GEPs converted to casts")static llvm::Statistic NumGEPsElim = {"codegenprepare", "NumGEPsElim"
, "Number of GEPs converted to casts", {0}, {false}}
;
107STATISTIC(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"
, {0}, {false}}
108 "sunken Cmps")static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses"
, "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps"
, {0}, {false}}
;
109STATISTIC(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"
, {0}, {false}}
110 "of sunken Casts")static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses"
, "Number of uses of Cast expressions replaced with uses " "of sunken Casts"
, {0}, {false}}
;
111STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
, {0}, {false}}
112 "computations were sunk")static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
, {0}, {false}}
;
113STATISTIC(NumMemoryInstsPhiCreated,static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions", {0}, {false
}}
114 "Number of phis created when address "static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions", {0}, {false
}}
115 "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
"computations were sunk to memory instructions", {0}, {false
}}
;
116STATISTIC(NumMemoryInstsSelectCreated,static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions", {0}, {false
}}
117 "Number of select created when address "static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions", {0}, {false
}}
118 "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
"computations were sunk to memory instructions", {0}, {false
}}
;
119STATISTIC(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", {0},
{false}}
;
120STATISTIC(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", {0}, {
false}}
;
121STATISTIC(NumAndsAdded,static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded"
, "Number of and mask instructions added to form ext loads", {
0}, {false}}
122 "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", {
0}, {false}}
;
123STATISTIC(NumAndUses, "Number of uses of and mask instructions optimized")static llvm::Statistic NumAndUses = {"codegenprepare", "NumAndUses"
, "Number of uses of and mask instructions optimized", {0}, {
false}}
;
124STATISTIC(NumRetsDup, "Number of return instructions duplicated")static llvm::Statistic NumRetsDup = {"codegenprepare", "NumRetsDup"
, "Number of return instructions duplicated", {0}, {false}}
;
125STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved")static llvm::Statistic NumDbgValueMoved = {"codegenprepare", "NumDbgValueMoved"
, "Number of debug value instructions moved", {0}, {false}}
;
126STATISTIC(NumSelectsExpanded, "Number of selects turned into branches")static llvm::Statistic NumSelectsExpanded = {"codegenprepare"
, "NumSelectsExpanded", "Number of selects turned into branches"
, {0}, {false}}
;
127STATISTIC(NumStoreExtractExposed, "Number of store(extractelement) exposed")static llvm::Statistic NumStoreExtractExposed = {"codegenprepare"
, "NumStoreExtractExposed", "Number of store(extractelement) exposed"
, {0}, {false}}
;
128
129static cl::opt<bool> DisableBranchOpts(
130 "disable-cgp-branch-opts", cl::Hidden, cl::init(false),
131 cl::desc("Disable branch optimizations in CodeGenPrepare"));
132
133static cl::opt<bool>
134 DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false),
135 cl::desc("Disable GC optimizations in CodeGenPrepare"));
136
137static cl::opt<bool> DisableSelectToBranch(
138 "disable-cgp-select2branch", cl::Hidden, cl::init(false),
139 cl::desc("Disable select to branch conversion."));
140
141static cl::opt<bool> AddrSinkUsingGEPs(
142 "addr-sink-using-gep", cl::Hidden, cl::init(true),
143 cl::desc("Address sinking in CGP using GEPs."));
144
145static cl::opt<bool> EnableAndCmpSinking(
146 "enable-andcmp-sinking", cl::Hidden, cl::init(true),
147 cl::desc("Enable sinkinig and/cmp into branches."));
148
149static cl::opt<bool> DisableStoreExtract(
150 "disable-cgp-store-extract", cl::Hidden, cl::init(false),
151 cl::desc("Disable store(extract) optimizations in CodeGenPrepare"));
152
153static cl::opt<bool> StressStoreExtract(
154 "stress-cgp-store-extract", cl::Hidden, cl::init(false),
155 cl::desc("Stress test store(extract) optimizations in CodeGenPrepare"));
156
157static cl::opt<bool> DisableExtLdPromotion(
158 "disable-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
159 cl::desc("Disable ext(promotable(ld)) -> promoted(ext(ld)) optimization in "
160 "CodeGenPrepare"));
161
162static cl::opt<bool> StressExtLdPromotion(
163 "stress-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
164 cl::desc("Stress test ext(promotable(ld)) -> promoted(ext(ld)) "
165 "optimization in CodeGenPrepare"));
166
167static cl::opt<bool> DisablePreheaderProtect(
168 "disable-preheader-prot", cl::Hidden, cl::init(false),
169 cl::desc("Disable protection against removing loop preheaders"));
170
171static cl::opt<bool> ProfileGuidedSectionPrefix(
172 "profile-guided-section-prefix", cl::Hidden, cl::init(true), cl::ZeroOrMore,
173 cl::desc("Use profile info to add section prefix for hot/cold functions"));
174
175static cl::opt<unsigned> FreqRatioToSkipMerge(
176 "cgp-freq-ratio-to-skip-merge", cl::Hidden, cl::init(2),
177 cl::desc("Skip merging empty blocks if (frequency of empty block) / "
178 "(frequency of destination block) is greater than this ratio"));
179
180static cl::opt<bool> ForceSplitStore(
181 "force-split-store", cl::Hidden, cl::init(false),
182 cl::desc("Force store splitting no matter what the target query says."));
183
184static cl::opt<bool>
185EnableTypePromotionMerge("cgp-type-promotion-merge", cl::Hidden,
186 cl::desc("Enable merging of redundant sexts when one is dominating"
187 " the other."), cl::init(true));
188
189static cl::opt<bool> DisableComplexAddrModes(
190 "disable-complex-addr-modes", cl::Hidden, cl::init(false),
191 cl::desc("Disables combining addressing modes with different parts "
192 "in optimizeMemoryInst."));
193
194static cl::opt<bool>
195AddrSinkNewPhis("addr-sink-new-phis", cl::Hidden, cl::init(false),
196 cl::desc("Allow creation of Phis in Address sinking."));
197
198static cl::opt<bool>
199AddrSinkNewSelects("addr-sink-new-select", cl::Hidden, cl::init(true),
200 cl::desc("Allow creation of selects in Address sinking."));
201
202static cl::opt<bool> AddrSinkCombineBaseReg(
203 "addr-sink-combine-base-reg", cl::Hidden, cl::init(true),
204 cl::desc("Allow combining of BaseReg field in Address sinking."));
205
206static cl::opt<bool> AddrSinkCombineBaseGV(
207 "addr-sink-combine-base-gv", cl::Hidden, cl::init(true),
208 cl::desc("Allow combining of BaseGV field in Address sinking."));
209
210static cl::opt<bool> AddrSinkCombineBaseOffs(
211 "addr-sink-combine-base-offs", cl::Hidden, cl::init(true),
212 cl::desc("Allow combining of BaseOffs field in Address sinking."));
213
214static cl::opt<bool> AddrSinkCombineScaledReg(
215 "addr-sink-combine-scaled-reg", cl::Hidden, cl::init(true),
216 cl::desc("Allow combining of ScaledReg field in Address sinking."));
217
218namespace {
219
220using SetOfInstrs = SmallPtrSet<Instruction *, 16>;
221using TypeIsSExt = PointerIntPair<Type *, 1, bool>;
222using InstrToOrigTy = DenseMap<Instruction *, TypeIsSExt>;
223using SExts = SmallVector<Instruction *, 16>;
224using ValueToSExts = DenseMap<Value *, SExts>;
225
226class TypePromotionTransaction;
227
228 class CodeGenPrepare : public FunctionPass {
229 const TargetMachine *TM = nullptr;
230 const TargetSubtargetInfo *SubtargetInfo;
231 const TargetLowering *TLI = nullptr;
232 const TargetRegisterInfo *TRI;
233 const TargetTransformInfo *TTI = nullptr;
234 const TargetLibraryInfo *TLInfo;
235 const LoopInfo *LI;
236 std::unique_ptr<BlockFrequencyInfo> BFI;
237 std::unique_ptr<BranchProbabilityInfo> BPI;
238
239 /// As we scan instructions optimizing them, this is the next instruction
240 /// to optimize. Transforms that can invalidate this should update it.
241 BasicBlock::iterator CurInstIterator;
242
243 /// Keeps track of non-local addresses that have been sunk into a block.
244 /// This allows us to avoid inserting duplicate code for blocks with
245 /// multiple load/stores of the same address. The usage of WeakTrackingVH
246 /// enables SunkAddrs to be treated as a cache whose entries can be
247 /// invalidated if a sunken address computation has been erased.
248 ValueMap<Value*, WeakTrackingVH> SunkAddrs;
249
250 /// Keeps track of all instructions inserted for the current function.
251 SetOfInstrs InsertedInsts;
252
253 /// Keeps track of the type of the related instruction before their
254 /// promotion for the current function.
255 InstrToOrigTy PromotedInsts;
256
257 /// Keep track of instructions removed during promotion.
258 SetOfInstrs RemovedInsts;
259
260 /// Keep track of sext chains based on their initial value.
261 DenseMap<Value *, Instruction *> SeenChainsForSExt;
262
263 /// Keep track of SExt promoted.
264 ValueToSExts ValToSExtendedUses;
265
266 /// True if CFG is modified in any way.
267 bool ModifiedDT;
268
269 /// True if optimizing for size.
270 bool OptSize;
271
272 /// DataLayout for the Function being processed.
273 const DataLayout *DL = nullptr;
274
275 public:
276 static char ID; // Pass identification, replacement for typeid
277
278 CodeGenPrepare() : FunctionPass(ID) {
279 initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
280 }
281
282 bool runOnFunction(Function &F) override;
283
284 StringRef getPassName() const override { return "CodeGen Prepare"; }
285
286 void getAnalysisUsage(AnalysisUsage &AU) const override {
287 // FIXME: When we can selectively preserve passes, preserve the domtree.
288 AU.addRequired<ProfileSummaryInfoWrapperPass>();
289 AU.addRequired<TargetLibraryInfoWrapperPass>();
290 AU.addRequired<TargetTransformInfoWrapperPass>();
291 AU.addRequired<LoopInfoWrapperPass>();
292 }
293
294 private:
295 bool eliminateFallThrough(Function &F);
296 bool eliminateMostlyEmptyBlocks(Function &F);
297 BasicBlock *findDestBlockOfMergeableEmptyBlock(BasicBlock *BB);
298 bool canMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
299 void eliminateMostlyEmptyBlock(BasicBlock *BB);
300 bool isMergingEmptyBlockProfitable(BasicBlock *BB, BasicBlock *DestBB,
301 bool isPreheader);
302 bool optimizeBlock(BasicBlock &BB, bool &ModifiedDT);
303 bool optimizeInst(Instruction *I, bool &ModifiedDT);
304 bool optimizeMemoryInst(Instruction *I, Value *Addr,
305 Type *AccessTy, unsigned AS);
306 bool optimizeInlineAsmInst(CallInst *CS);
307 bool optimizeCallInst(CallInst *CI, bool &ModifiedDT);
308 bool optimizeExt(Instruction *&I);
309 bool optimizeExtUses(Instruction *I);
310 bool optimizeLoadExt(LoadInst *I);
311 bool optimizeSelectInst(SelectInst *SI);
312 bool optimizeShuffleVectorInst(ShuffleVectorInst *SI);
313 bool optimizeSwitchInst(SwitchInst *CI);
314 bool optimizeExtractElementInst(Instruction *Inst);
315 bool dupRetToEnableTailCallOpts(BasicBlock *BB);
316 bool placeDbgValues(Function &F);
317 bool canFormExtLd(const SmallVectorImpl<Instruction *> &MovedExts,
318 LoadInst *&LI, Instruction *&Inst, bool HasPromoted);
319 bool tryToPromoteExts(TypePromotionTransaction &TPT,
320 const SmallVectorImpl<Instruction *> &Exts,
321 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
322 unsigned CreatedInstsCost = 0);
323 bool mergeSExts(Function &F);
324 bool performAddressTypePromotion(
325 Instruction *&Inst,
326 bool AllowPromotionWithoutCommonHeader,
327 bool HasPromoted, TypePromotionTransaction &TPT,
328 SmallVectorImpl<Instruction *> &SpeculativelyMovedExts);
329 bool splitBranchCondition(Function &F);
330 bool simplifyOffsetableRelocate(Instruction &I);
331 };
332
333} // end anonymous namespace
334
335char CodeGenPrepare::ID = 0;
336
337INITIALIZE_PASS_BEGIN(CodeGenPrepare, DEBUG_TYPE,static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
338 "Optimize for code generation", false, false)static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
339INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)initializeProfileSummaryInfoWrapperPassPass(Registry);
340INITIALIZE_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)); }
341 "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)); }
342
343FunctionPass *llvm::createCodeGenPreparePass() { return new CodeGenPrepare(); }
344
345bool CodeGenPrepare::runOnFunction(Function &F) {
346 if (skipFunction(F))
347 return false;
348
349 DL = &F.getParent()->getDataLayout();
350
351 bool EverMadeChange = false;
352 // Clear per function information.
353 InsertedInsts.clear();
354 PromotedInsts.clear();
355
356 ModifiedDT = false;
357 if (auto *TPC = getAnalysisIfAvailable<TargetPassConfig>()) {
358 TM = &TPC->getTM<TargetMachine>();
359 SubtargetInfo = TM->getSubtargetImpl(F);
360 TLI = SubtargetInfo->getTargetLowering();
361 TRI = SubtargetInfo->getRegisterInfo();
362 }
363 TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
364 TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
365 LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
366 BPI.reset(new BranchProbabilityInfo(F, *LI));
367 BFI.reset(new BlockFrequencyInfo(F, *BPI, *LI));
368 OptSize = F.optForSize();
369
370 ProfileSummaryInfo *PSI =
371 getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
372 if (ProfileGuidedSectionPrefix) {
373 if (PSI->isFunctionHotInCallGraph(&F, *BFI))
374 F.setSectionPrefix(".hot");
375 else if (PSI->isFunctionColdInCallGraph(&F, *BFI))
376 F.setSectionPrefix(".unlikely");
377 }
378
379 /// This optimization identifies DIV instructions that can be
380 /// profitably bypassed and carried out with a shorter, faster divide.
381 if (!OptSize && !PSI->hasHugeWorkingSetSize() && TLI &&
382 TLI->isSlowDivBypassed()) {
383 const DenseMap<unsigned int, unsigned int> &BypassWidths =
384 TLI->getBypassSlowDivWidths();
385 BasicBlock* BB = &*F.begin();
386 while (BB != nullptr) {
387 // bypassSlowDivision may create new BBs, but we don't want to reapply the
388 // optimization to those blocks.
389 BasicBlock* Next = BB->getNextNode();
390 EverMadeChange |= bypassSlowDivision(BB, BypassWidths);
391 BB = Next;
392 }
393 }
394
395 // Eliminate blocks that contain only PHI nodes and an
396 // unconditional branch.
397 EverMadeChange |= eliminateMostlyEmptyBlocks(F);
398
399 // llvm.dbg.value is far away from the value then iSel may not be able
400 // handle it properly. iSel will drop llvm.dbg.value if it can not
401 // find a node corresponding to the value.
402 EverMadeChange |= placeDbgValues(F);
403
404 if (!DisableBranchOpts)
405 EverMadeChange |= splitBranchCondition(F);
406
407 // Split some critical edges where one of the sources is an indirect branch,
408 // to help generate sane code for PHIs involving such edges.
409 EverMadeChange |= SplitIndirectBrCriticalEdges(F);
410
411 bool MadeChange = true;
412 while (MadeChange) {
413 MadeChange = false;
414 SeenChainsForSExt.clear();
415 ValToSExtendedUses.clear();
416 RemovedInsts.clear();
417 for (Function::iterator I = F.begin(); I != F.end(); ) {
418 BasicBlock *BB = &*I++;
419 bool ModifiedDTOnIteration = false;
420 MadeChange |= optimizeBlock(*BB, ModifiedDTOnIteration);
421
422 // Restart BB iteration if the dominator tree of the Function was changed
423 if (ModifiedDTOnIteration)
424 break;
425 }
426 if (EnableTypePromotionMerge && !ValToSExtendedUses.empty())
427 MadeChange |= mergeSExts(F);
428
429 // Really free removed instructions during promotion.
430 for (Instruction *I : RemovedInsts)
431 I->deleteValue();
432
433 EverMadeChange |= MadeChange;
434 }
435
436 SunkAddrs.clear();
437
438 if (!DisableBranchOpts) {
439 MadeChange = false;
440 SmallPtrSet<BasicBlock*, 8> WorkList;
441 for (BasicBlock &BB : F) {
442 SmallVector<BasicBlock *, 2> Successors(succ_begin(&BB), succ_end(&BB));
443 MadeChange |= ConstantFoldTerminator(&BB, true);
444 if (!MadeChange) continue;
445
446 for (SmallVectorImpl<BasicBlock*>::iterator
447 II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
448 if (pred_begin(*II) == pred_end(*II))
449 WorkList.insert(*II);
450 }
451
452 // Delete the dead blocks and any of their dead successors.
453 MadeChange |= !WorkList.empty();
454 while (!WorkList.empty()) {
455 BasicBlock *BB = *WorkList.begin();
456 WorkList.erase(BB);
457 SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
458
459 DeleteDeadBlock(BB);
460
461 for (SmallVectorImpl<BasicBlock*>::iterator
462 II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
463 if (pred_begin(*II) == pred_end(*II))
464 WorkList.insert(*II);
465 }
466
467 // Merge pairs of basic blocks with unconditional branches, connected by
468 // a single edge.
469 if (EverMadeChange || MadeChange)
470 MadeChange |= eliminateFallThrough(F);
471
472 EverMadeChange |= MadeChange;
473 }
474
475 if (!DisableGCOpts) {
476 SmallVector<Instruction *, 2> Statepoints;
477 for (BasicBlock &BB : F)
478 for (Instruction &I : BB)
479 if (isStatepoint(I))
480 Statepoints.push_back(&I);
481 for (auto &I : Statepoints)
482 EverMadeChange |= simplifyOffsetableRelocate(*I);
483 }
484
485 return EverMadeChange;
486}
487
488/// Merge basic blocks which are connected by a single edge, where one of the
489/// basic blocks has a single successor pointing to the other basic block,
490/// which has a single predecessor.
491bool CodeGenPrepare::eliminateFallThrough(Function &F) {
492 bool Changed = false;
493 // Scan all of the blocks in the function, except for the entry block.
494 for (Function::iterator I = std::next(F.begin()), E = F.end(); I != E;) {
495 BasicBlock *BB = &*I++;
496 // If the destination block has a single pred, then this is a trivial
497 // edge, just collapse it.
498 BasicBlock *SinglePred = BB->getSinglePredecessor();
499
500 // Don't merge if BB's address is taken.
501 if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue;
502
503 BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
504 if (Term && !Term->isConditional()) {
505 Changed = true;
506 DEBUG(dbgs() << "To merge:\n"<< *SinglePred << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "To merge:\n"<< *
SinglePred << "\n\n\n"; } } while (false)
;
507 // Remember if SinglePred was the entry block of the function.
508 // If so, we will need to move BB back to the entry position.
509 bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
510 MergeBasicBlockIntoOnlyPred(BB, nullptr);
511
512 if (isEntry && BB != &BB->getParent()->getEntryBlock())
513 BB->moveBefore(&BB->getParent()->getEntryBlock());
514
515 // We have erased a block. Update the iterator.
516 I = BB->getIterator();
517 }
518 }
519 return Changed;
520}
521
522/// Find a destination block from BB if BB is mergeable empty block.
523BasicBlock *CodeGenPrepare::findDestBlockOfMergeableEmptyBlock(BasicBlock *BB) {
524 // If this block doesn't end with an uncond branch, ignore it.
525 BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
526 if (!BI || !BI->isUnconditional())
527 return nullptr;
528
529 // If the instruction before the branch (skipping debug info) isn't a phi
530 // node, then other stuff is happening here.
531 BasicBlock::iterator BBI = BI->getIterator();
532 if (BBI != BB->begin()) {
533 --BBI;
534 while (isa<DbgInfoIntrinsic>(BBI)) {
535 if (BBI == BB->begin())
536 break;
537 --BBI;
538 }
539 if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI))
540 return nullptr;
541 }
542
543 // Do not break infinite loops.
544 BasicBlock *DestBB = BI->getSuccessor(0);
545 if (DestBB == BB)
546 return nullptr;
547
548 if (!canMergeBlocks(BB, DestBB))
549 DestBB = nullptr;
550
551 return DestBB;
552}
553
554/// Eliminate blocks that contain only PHI nodes, debug info directives, and an
555/// unconditional branch. Passes before isel (e.g. LSR/loopsimplify) often split
556/// edges in ways that are non-optimal for isel. Start by eliminating these
557/// blocks so we can split them the way we want them.
558bool CodeGenPrepare::eliminateMostlyEmptyBlocks(Function &F) {
559 SmallPtrSet<BasicBlock *, 16> Preheaders;
560 SmallVector<Loop *, 16> LoopList(LI->begin(), LI->end());
561 while (!LoopList.empty()) {
562 Loop *L = LoopList.pop_back_val();
563 LoopList.insert(LoopList.end(), L->begin(), L->end());
564 if (BasicBlock *Preheader = L->getLoopPreheader())
565 Preheaders.insert(Preheader);
566 }
567
568 bool MadeChange = false;
569 // Note that this intentionally skips the entry block.
570 for (Function::iterator I = std::next(F.begin()), E = F.end(); I != E;) {
571 BasicBlock *BB = &*I++;
572 BasicBlock *DestBB = findDestBlockOfMergeableEmptyBlock(BB);
573 if (!DestBB ||
574 !isMergingEmptyBlockProfitable(BB, DestBB, Preheaders.count(BB)))
575 continue;
576
577 eliminateMostlyEmptyBlock(BB);
578 MadeChange = true;
579 }
580 return MadeChange;
581}
582
583bool CodeGenPrepare::isMergingEmptyBlockProfitable(BasicBlock *BB,
584 BasicBlock *DestBB,
585 bool isPreheader) {
586 // Do not delete loop preheaders if doing so would create a critical edge.
587 // Loop preheaders can be good locations to spill registers. If the
588 // preheader is deleted and we create a critical edge, registers may be
589 // spilled in the loop body instead.
590 if (!DisablePreheaderProtect && isPreheader &&
591 !(BB->getSinglePredecessor() &&
592 BB->getSinglePredecessor()->getSingleSuccessor()))
593 return false;
594
595 // Try to skip merging if the unique predecessor of BB is terminated by a
596 // switch or indirect branch instruction, and BB is used as an incoming block
597 // of PHIs in DestBB. In such case, merging BB and DestBB would cause ISel to
598 // add COPY instructions in the predecessor of BB instead of BB (if it is not
599 // merged). Note that the critical edge created by merging such blocks wont be
600 // split in MachineSink because the jump table is not analyzable. By keeping
601 // such empty block (BB), ISel will place COPY instructions in BB, not in the
602 // predecessor of BB.
603 BasicBlock *Pred = BB->getUniquePredecessor();
604 if (!Pred ||
605 !(isa<SwitchInst>(Pred->getTerminator()) ||
606 isa<IndirectBrInst>(Pred->getTerminator())))
607 return true;
608
609 if (BB->getTerminator() != BB->getFirstNonPHI())
610 return true;
611
612 // We use a simple cost heuristic which determine skipping merging is
613 // profitable if the cost of skipping merging is less than the cost of
614 // merging : Cost(skipping merging) < Cost(merging BB), where the
615 // Cost(skipping merging) is Freq(BB) * (Cost(Copy) + Cost(Branch)), and
616 // the Cost(merging BB) is Freq(Pred) * Cost(Copy).
617 // Assuming Cost(Copy) == Cost(Branch), we could simplify it to :
618 // Freq(Pred) / Freq(BB) > 2.
619 // Note that if there are multiple empty blocks sharing the same incoming
620 // value for the PHIs in the DestBB, we consider them together. In such
621 // case, Cost(merging BB) will be the sum of their frequencies.
622
623 if (!isa<PHINode>(DestBB->begin()))
624 return true;
625
626 SmallPtrSet<BasicBlock *, 16> SameIncomingValueBBs;
627
628 // Find all other incoming blocks from which incoming values of all PHIs in
629 // DestBB are the same as the ones from BB.
630 for (pred_iterator PI = pred_begin(DestBB), E = pred_end(DestBB); PI != E;
631 ++PI) {
632 BasicBlock *DestBBPred = *PI;
633 if (DestBBPred == BB)
634 continue;
635
636 if (llvm::all_of(DestBB->phis(), [&](const PHINode &DestPN) {
637 return DestPN.getIncomingValueForBlock(BB) ==
638 DestPN.getIncomingValueForBlock(DestBBPred);
639 }))
640 SameIncomingValueBBs.insert(DestBBPred);
641 }
642
643 // See if all BB's incoming values are same as the value from Pred. In this
644 // case, no reason to skip merging because COPYs are expected to be place in
645 // Pred already.
646 if (SameIncomingValueBBs.count(Pred))
647 return true;
648
649 BlockFrequency PredFreq = BFI->getBlockFreq(Pred);
650 BlockFrequency BBFreq = BFI->getBlockFreq(BB);
651
652 for (auto SameValueBB : SameIncomingValueBBs)
653 if (SameValueBB->getUniquePredecessor() == Pred &&
654 DestBB == findDestBlockOfMergeableEmptyBlock(SameValueBB))
655 BBFreq += BFI->getBlockFreq(SameValueBB);
656
657 return PredFreq.getFrequency() <=
658 BBFreq.getFrequency() * FreqRatioToSkipMerge;
659}
660
661/// Return true if we can merge BB into DestBB if there is a single
662/// unconditional branch between them, and BB contains no other non-phi
663/// instructions.
664bool CodeGenPrepare::canMergeBlocks(const BasicBlock *BB,
665 const BasicBlock *DestBB) const {
666 // We only want to eliminate blocks whose phi nodes are used by phi nodes in
667 // the successor. If there are more complex condition (e.g. preheaders),
668 // don't mess around with them.
669 for (const PHINode &PN : BB->phis()) {
670 for (const User *U : PN.users()) {
671 const Instruction *UI = cast<Instruction>(U);
672 if (UI->getParent() != DestBB || !isa<PHINode>(UI))
673 return false;
674 // If User is inside DestBB block and it is a PHINode then check
675 // incoming value. If incoming value is not from BB then this is
676 // a complex condition (e.g. preheaders) we want to avoid here.
677 if (UI->getParent() == DestBB) {
678 if (const PHINode *UPN = dyn_cast<PHINode>(UI))
679 for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
680 Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
681 if (Insn && Insn->getParent() == BB &&
682 Insn->getParent() != UPN->getIncomingBlock(I))
683 return false;
684 }
685 }
686 }
687 }
688
689 // If BB and DestBB contain any common predecessors, then the phi nodes in BB
690 // and DestBB may have conflicting incoming values for the block. If so, we
691 // can't merge the block.
692 const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
693 if (!DestBBPN) return true; // no conflict.
694
695 // Collect the preds of BB.
696 SmallPtrSet<const BasicBlock*, 16> BBPreds;
697 if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
698 // It is faster to get preds from a PHI than with pred_iterator.
699 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
700 BBPreds.insert(BBPN->getIncomingBlock(i));
701 } else {
702 BBPreds.insert(pred_begin(BB), pred_end(BB));
703 }
704
705 // Walk the preds of DestBB.
706 for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
707 BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
708 if (BBPreds.count(Pred)) { // Common predecessor?
709 for (const PHINode &PN : DestBB->phis()) {
710 const Value *V1 = PN.getIncomingValueForBlock(Pred);
711 const Value *V2 = PN.getIncomingValueForBlock(BB);
712
713 // If V2 is a phi node in BB, look up what the mapped value will be.
714 if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
715 if (V2PN->getParent() == BB)
716 V2 = V2PN->getIncomingValueForBlock(Pred);
717
718 // If there is a conflict, bail out.
719 if (V1 != V2) return false;
720 }
721 }
722 }
723
724 return true;
725}
726
727/// Eliminate a basic block that has only phi's and an unconditional branch in
728/// it.
729void CodeGenPrepare::eliminateMostlyEmptyBlock(BasicBlock *BB) {
730 BranchInst *BI = cast<BranchInst>(BB->getTerminator());
731 BasicBlock *DestBB = BI->getSuccessor(0);
732
733 DEBUG(dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n" << *BB << *DestBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"
<< *BB << *DestBB; } } while (false)
;
734
735 // If the destination block has a single pred, then this is a trivial edge,
736 // just collapse it.
737 if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
738 if (SinglePred != DestBB) {
739 // Remember if SinglePred was the entry block of the function. If so, we
740 // will need to move BB back to the entry position.
741 bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
742 MergeBasicBlockIntoOnlyPred(DestBB, nullptr);
743
744 if (isEntry && BB != &BB->getParent()->getEntryBlock())
745 BB->moveBefore(&BB->getParent()->getEntryBlock());
746
747 DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "AFTER:\n" << *DestBB
<< "\n\n\n"; } } while (false)
;
748 return;
749 }
750 }
751
752 // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
753 // to handle the new incoming edges it is about to have.
754 for (PHINode &PN : DestBB->phis()) {
755 // Remove the incoming value for BB, and remember it.
756 Value *InVal = PN.removeIncomingValue(BB, false);
757
758 // Two options: either the InVal is a phi node defined in BB or it is some
759 // value that dominates BB.
760 PHINode *InValPhi = dyn_cast<PHINode>(InVal);
761 if (InValPhi && InValPhi->getParent() == BB) {
762 // Add all of the input values of the input PHI as inputs of this phi.
763 for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
764 PN.addIncoming(InValPhi->getIncomingValue(i),
765 InValPhi->getIncomingBlock(i));
766 } else {
767 // Otherwise, add one instance of the dominating value for each edge that
768 // we will be adding.
769 if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
770 for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
771 PN.addIncoming(InVal, BBPN->getIncomingBlock(i));
772 } else {
773 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
774 PN.addIncoming(InVal, *PI);
775 }
776 }
777 }
778
779 // The PHIs are now updated, change everything that refers to BB to use
780 // DestBB and remove BB.
781 BB->replaceAllUsesWith(DestBB);
782 BB->eraseFromParent();
783 ++NumBlocksElim;
784
785 DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "AFTER:\n" << *DestBB
<< "\n\n\n"; } } while (false)
;
786}
787
788// Computes a map of base pointer relocation instructions to corresponding
789// derived pointer relocation instructions given a vector of all relocate calls
790static void computeBaseDerivedRelocateMap(
791 const SmallVectorImpl<GCRelocateInst *> &AllRelocateCalls,
792 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>>
793 &RelocateInstMap) {
794 // Collect information in two maps: one primarily for locating the base object
795 // while filling the second map; the second map is the final structure holding
796 // a mapping between Base and corresponding Derived relocate calls
797 DenseMap<std::pair<unsigned, unsigned>, GCRelocateInst *> RelocateIdxMap;
798 for (auto *ThisRelocate : AllRelocateCalls) {
799 auto K = std::make_pair(ThisRelocate->getBasePtrIndex(),
800 ThisRelocate->getDerivedPtrIndex());
801 RelocateIdxMap.insert(std::make_pair(K, ThisRelocate));
802 }
803 for (auto &Item : RelocateIdxMap) {
804 std::pair<unsigned, unsigned> Key = Item.first;
805 if (Key.first == Key.second)
806 // Base relocation: nothing to insert
807 continue;
808
809 GCRelocateInst *I = Item.second;
810 auto BaseKey = std::make_pair(Key.first, Key.first);
811
812 // We're iterating over RelocateIdxMap so we cannot modify it.
813 auto MaybeBase = RelocateIdxMap.find(BaseKey);
814 if (MaybeBase == RelocateIdxMap.end())
815 // TODO: We might want to insert a new base object relocate and gep off
816 // that, if there are enough derived object relocates.
817 continue;
818
819 RelocateInstMap[MaybeBase->second].push_back(I);
820 }
821}
822
823// Accepts a GEP and extracts the operands into a vector provided they're all
824// small integer constants
825static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
826 SmallVectorImpl<Value *> &OffsetV) {
827 for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
828 // Only accept small constant integer operands
829 auto Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
830 if (!Op || Op->getZExtValue() > 20)
831 return false;
832 }
833
834 for (unsigned i = 1; i < GEP->getNumOperands(); i++)
835 OffsetV.push_back(GEP->getOperand(i));
836 return true;
837}
838
839// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
840// replace, computes a replacement, and affects it.
841static bool
842simplifyRelocatesOffABase(GCRelocateInst *RelocatedBase,
843 const SmallVectorImpl<GCRelocateInst *> &Targets) {
844 bool MadeChange = false;
845 // We must ensure the relocation of derived pointer is defined after
846 // relocation of base pointer. If we find a relocation corresponding to base
847 // defined earlier than relocation of base then we move relocation of base
848 // right before found relocation. We consider only relocation in the same
849 // basic block as relocation of base. Relocations from other basic block will
850 // be skipped by optimization and we do not care about them.
851 for (auto R = RelocatedBase->getParent()->getFirstInsertionPt();
852 &*R != RelocatedBase; ++R)
853 if (auto RI = dyn_cast<GCRelocateInst>(R))
854 if (RI->getStatepoint() == RelocatedBase->getStatepoint())
855 if (RI->getBasePtrIndex() == RelocatedBase->getBasePtrIndex()) {
856 RelocatedBase->moveBefore(RI);
857 break;
858 }
859
860 for (GCRelocateInst *ToReplace : Targets) {
861 assert(ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() &&(static_cast <bool> (ToReplace->getBasePtrIndex() ==
RelocatedBase->getBasePtrIndex() && "Not relocating a derived object of the original base object"
) ? void (0) : __assert_fail ("ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() && \"Not relocating a derived object of the original base object\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 862, __extension__ __PRETTY_FUNCTION__))
862 "Not relocating a derived object of the original base object")(static_cast <bool> (ToReplace->getBasePtrIndex() ==
RelocatedBase->getBasePtrIndex() && "Not relocating a derived object of the original base object"
) ? void (0) : __assert_fail ("ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() && \"Not relocating a derived object of the original base object\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 862, __extension__ __PRETTY_FUNCTION__))
;
863 if (ToReplace->getBasePtrIndex() == ToReplace->getDerivedPtrIndex()) {
864 // A duplicate relocate call. TODO: coalesce duplicates.
865 continue;
866 }
867
868 if (RelocatedBase->getParent() != ToReplace->getParent()) {
869 // Base and derived relocates are in different basic blocks.
870 // In this case transform is only valid when base dominates derived
871 // relocate. However it would be too expensive to check dominance
872 // for each such relocate, so we skip the whole transformation.
873 continue;
874 }
875
876 Value *Base = ToReplace->getBasePtr();
877 auto Derived = dyn_cast<GetElementPtrInst>(ToReplace->getDerivedPtr());
878 if (!Derived || Derived->getPointerOperand() != Base)
879 continue;
880
881 SmallVector<Value *, 2> OffsetV;
882 if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
883 continue;
884
885 // Create a Builder and replace the target callsite with a gep
886 assert(RelocatedBase->getNextNode() &&(static_cast <bool> (RelocatedBase->getNextNode() &&
"Should always have one since it's not a terminator") ? void
(0) : __assert_fail ("RelocatedBase->getNextNode() && \"Should always have one since it's not a terminator\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 887, __extension__ __PRETTY_FUNCTION__))
887 "Should always have one since it's not a terminator")(static_cast <bool> (RelocatedBase->getNextNode() &&
"Should always have one since it's not a terminator") ? void
(0) : __assert_fail ("RelocatedBase->getNextNode() && \"Should always have one since it's not a terminator\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 887, __extension__ __PRETTY_FUNCTION__))
;
888
889 // Insert after RelocatedBase
890 IRBuilder<> Builder(RelocatedBase->getNextNode());
891 Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
892
893 // If gc_relocate does not match the actual type, cast it to the right type.
894 // In theory, there must be a bitcast after gc_relocate if the type does not
895 // match, and we should reuse it to get the derived pointer. But it could be
896 // cases like this:
897 // bb1:
898 // ...
899 // %g1 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
900 // br label %merge
901 //
902 // bb2:
903 // ...
904 // %g2 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
905 // br label %merge
906 //
907 // merge:
908 // %p1 = phi i8 addrspace(1)* [ %g1, %bb1 ], [ %g2, %bb2 ]
909 // %cast = bitcast i8 addrspace(1)* %p1 in to i32 addrspace(1)*
910 //
911 // In this case, we can not find the bitcast any more. So we insert a new bitcast
912 // no matter there is already one or not. In this way, we can handle all cases, and
913 // the extra bitcast should be optimized away in later passes.
914 Value *ActualRelocatedBase = RelocatedBase;
915 if (RelocatedBase->getType() != Base->getType()) {
916 ActualRelocatedBase =
917 Builder.CreateBitCast(RelocatedBase, Base->getType());
918 }
919 Value *Replacement = Builder.CreateGEP(
920 Derived->getSourceElementType(), ActualRelocatedBase, makeArrayRef(OffsetV));
921 Replacement->takeName(ToReplace);
922 // If the newly generated derived pointer's type does not match the original derived
923 // pointer's type, cast the new derived pointer to match it. Same reasoning as above.
924 Value *ActualReplacement = Replacement;
925 if (Replacement->getType() != ToReplace->getType()) {
926 ActualReplacement =
927 Builder.CreateBitCast(Replacement, ToReplace->getType());
928 }
929 ToReplace->replaceAllUsesWith(ActualReplacement);
930 ToReplace->eraseFromParent();
931
932 MadeChange = true;
933 }
934 return MadeChange;
935}
936
937// Turns this:
938//
939// %base = ...
940// %ptr = gep %base + 15
941// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
942// %base' = relocate(%tok, i32 4, i32 4)
943// %ptr' = relocate(%tok, i32 4, i32 5)
944// %val = load %ptr'
945//
946// into this:
947//
948// %base = ...
949// %ptr = gep %base + 15
950// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
951// %base' = gc.relocate(%tok, i32 4, i32 4)
952// %ptr' = gep %base' + 15
953// %val = load %ptr'
954bool CodeGenPrepare::simplifyOffsetableRelocate(Instruction &I) {
955 bool MadeChange = false;
956 SmallVector<GCRelocateInst *, 2> AllRelocateCalls;
957
958 for (auto *U : I.users())
959 if (GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U))
960 // Collect all the relocate calls associated with a statepoint
961 AllRelocateCalls.push_back(Relocate);
962
963 // We need atleast one base pointer relocation + one derived pointer
964 // relocation to mangle
965 if (AllRelocateCalls.size() < 2)
966 return false;
967
968 // RelocateInstMap is a mapping from the base relocate instruction to the
969 // corresponding derived relocate instructions
970 DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>> RelocateInstMap;
971 computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
972 if (RelocateInstMap.empty())
973 return false;
974
975 for (auto &Item : RelocateInstMap)
976 // Item.first is the RelocatedBase to offset against
977 // Item.second is the vector of Targets to replace
978 MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
979 return MadeChange;
980}
981
982/// SinkCast - Sink the specified cast instruction into its user blocks
983static bool SinkCast(CastInst *CI) {
984 BasicBlock *DefBB = CI->getParent();
985
986 /// InsertedCasts - Only insert a cast in each block once.
987 DenseMap<BasicBlock*, CastInst*> InsertedCasts;
988
989 bool MadeChange = false;
990 for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
991 UI != E; ) {
992 Use &TheUse = UI.getUse();
993 Instruction *User = cast<Instruction>(*UI);
994
995 // Figure out which BB this cast is used in. For PHI's this is the
996 // appropriate predecessor block.
997 BasicBlock *UserBB = User->getParent();
998 if (PHINode *PN = dyn_cast<PHINode>(User)) {
999 UserBB = PN->getIncomingBlock(TheUse);
1000 }
1001
1002 // Preincrement use iterator so we don't invalidate it.
1003 ++UI;
1004
1005 // The first insertion point of a block containing an EH pad is after the
1006 // pad. If the pad is the user, we cannot sink the cast past the pad.
1007 if (User->isEHPad())
1008 continue;
1009
1010 // If the block selected to receive the cast is an EH pad that does not
1011 // allow non-PHI instructions before the terminator, we can't sink the
1012 // cast.
1013 if (UserBB->getTerminator()->isEHPad())
1014 continue;
1015
1016 // If this user is in the same block as the cast, don't change the cast.
1017 if (UserBB == DefBB) continue;
1018
1019 // If we have already inserted a cast into this block, use it.
1020 CastInst *&InsertedCast = InsertedCasts[UserBB];
1021
1022 if (!InsertedCast) {
1023 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1024 assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
(0) : __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1024, __extension__ __PRETTY_FUNCTION__))
;
1025 InsertedCast = CastInst::Create(CI->getOpcode(), CI->getOperand(0),
1026 CI->getType(), "", &*InsertPt);
1027 }
1028
1029 // Replace a use of the cast with a use of the new cast.
1030 TheUse = InsertedCast;
1031 MadeChange = true;
1032 ++NumCastUses;
1033 }
1034
1035 // If we removed all uses, nuke the cast.
1036 if (CI->use_empty()) {
1037 salvageDebugInfo(*CI);
1038 CI->eraseFromParent();
1039 MadeChange = true;
1040 }
1041
1042 return MadeChange;
1043}
1044
1045/// If the specified cast instruction is a noop copy (e.g. it's casting from
1046/// one pointer type to another, i32->i8 on PPC), sink it into user blocks to
1047/// reduce the number of virtual registers that must be created and coalesced.
1048///
1049/// Return true if any changes are made.
1050static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI,
1051 const DataLayout &DL) {
1052 // Sink only "cheap" (or nop) address-space casts. This is a weaker condition
1053 // than sinking only nop casts, but is helpful on some platforms.
1054 if (auto *ASC = dyn_cast<AddrSpaceCastInst>(CI)) {
1055 if (!TLI.isCheapAddrSpaceCast(ASC->getSrcAddressSpace(),
1056 ASC->getDestAddressSpace()))
1057 return false;
1058 }
1059
1060 // If this is a noop copy,
1061 EVT SrcVT = TLI.getValueType(DL, CI->getOperand(0)->getType());
1062 EVT DstVT = TLI.getValueType(DL, CI->getType());
1063
1064 // This is an fp<->int conversion?
1065 if (SrcVT.isInteger() != DstVT.isInteger())
1066 return false;
1067
1068 // If this is an extension, it will be a zero or sign extension, which
1069 // isn't a noop.
1070 if (SrcVT.bitsLT(DstVT)) return false;
1071
1072 // If these values will be promoted, find out what they will be promoted
1073 // to. This helps us consider truncates on PPC as noop copies when they
1074 // are.
1075 if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
1076 TargetLowering::TypePromoteInteger)
1077 SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
1078 if (TLI.getTypeAction(CI->getContext(), DstVT) ==
1079 TargetLowering::TypePromoteInteger)
1080 DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
1081
1082 // If, after promotion, these are the same types, this is a noop copy.
1083 if (SrcVT != DstVT)
1084 return false;
1085
1086 return SinkCast(CI);
1087}
1088
1089/// Try to combine CI into a call to the llvm.uadd.with.overflow intrinsic if
1090/// possible.
1091///
1092/// Return true if any changes were made.
1093static bool CombineUAddWithOverflow(CmpInst *CI) {
1094 Value *A, *B;
1095 Instruction *AddI;
1096 if (!match(CI,
1097 m_UAddWithOverflow(m_Value(A), m_Value(B), m_Instruction(AddI))))
1098 return false;
1099
1100 Type *Ty = AddI->getType();
1101 if (!isa<IntegerType>(Ty))
1102 return false;
1103
1104 // We don't want to move around uses of condition values this late, so we we
1105 // check if it is legal to create the call to the intrinsic in the basic
1106 // block containing the icmp:
1107
1108 if (AddI->getParent() != CI->getParent() && !AddI->hasOneUse())
1109 return false;
1110
1111#ifndef NDEBUG
1112 // Someday m_UAddWithOverflow may get smarter, but this is a safe assumption
1113 // for now:
1114 if (AddI->hasOneUse())
1115 assert(*AddI->user_begin() == CI && "expected!")(static_cast <bool> (*AddI->user_begin() == CI &&
"expected!") ? void (0) : __assert_fail ("*AddI->user_begin() == CI && \"expected!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1115, __extension__ __PRETTY_FUNCTION__))
;
1116#endif
1117
1118 Module *M = CI->getModule();
1119 Value *F = Intrinsic::getDeclaration(M, Intrinsic::uadd_with_overflow, Ty);
1120
1121 auto *InsertPt = AddI->hasOneUse() ? CI : AddI;
1122
1123 auto *UAddWithOverflow =
1124 CallInst::Create(F, {A, B}, "uadd.overflow", InsertPt);
1125 auto *UAdd = ExtractValueInst::Create(UAddWithOverflow, 0, "uadd", InsertPt);
1126 auto *Overflow =
1127 ExtractValueInst::Create(UAddWithOverflow, 1, "overflow", InsertPt);
1128
1129 CI->replaceAllUsesWith(Overflow);
1130 AddI->replaceAllUsesWith(UAdd);
1131 CI->eraseFromParent();
1132 AddI->eraseFromParent();
1133 return true;
1134}
1135
1136/// Sink the given CmpInst into user blocks to reduce the number of virtual
1137/// registers that must be created and coalesced. This is a clear win except on
1138/// targets with multiple condition code registers (PowerPC), where it might
1139/// lose; some adjustment may be wanted there.
1140///
1141/// Return true if any changes are made.
1142static bool SinkCmpExpression(CmpInst *CI, const TargetLowering *TLI) {
1143 BasicBlock *DefBB = CI->getParent();
1144
1145 // Avoid sinking soft-FP comparisons, since this can move them into a loop.
1146 if (TLI && TLI->useSoftFloat() && isa<FCmpInst>(CI))
1147 return false;
1148
1149 // Only insert a cmp in each block once.
1150 DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
1151
1152 bool MadeChange = false;
1153 for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
1154 UI != E; ) {
1155 Use &TheUse = UI.getUse();
1156 Instruction *User = cast<Instruction>(*UI);
1157
1158 // Preincrement use iterator so we don't invalidate it.
1159 ++UI;
1160
1161 // Don't bother for PHI nodes.
1162 if (isa<PHINode>(User))
1163 continue;
1164
1165 // Figure out which BB this cmp is used in.
1166 BasicBlock *UserBB = User->getParent();
1167
1168 // If this user is in the same block as the cmp, don't change the cmp.
1169 if (UserBB == DefBB) continue;
1170
1171 // If we have already inserted a cmp into this block, use it.
1172 CmpInst *&InsertedCmp = InsertedCmps[UserBB];
1173
1174 if (!InsertedCmp) {
1175 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1176 assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
(0) : __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1176, __extension__ __PRETTY_FUNCTION__))
;
1177 InsertedCmp =
1178 CmpInst::Create(CI->getOpcode(), CI->getPredicate(),
1179 CI->getOperand(0), CI->getOperand(1), "", &*InsertPt);
1180 // Propagate the debug info.
1181 InsertedCmp->setDebugLoc(CI->getDebugLoc());
1182 }
1183
1184 // Replace a use of the cmp with a use of the new cmp.
1185 TheUse = InsertedCmp;
1186 MadeChange = true;
1187 ++NumCmpUses;
1188 }
1189
1190 // If we removed all uses, nuke the cmp.
1191 if (CI->use_empty()) {
1192 CI->eraseFromParent();
1193 MadeChange = true;
1194 }
1195
1196 return MadeChange;
1197}
1198
1199static bool OptimizeCmpExpression(CmpInst *CI, const TargetLowering *TLI) {
1200 if (SinkCmpExpression(CI, TLI))
1201 return true;
1202
1203 if (CombineUAddWithOverflow(CI))
1204 return true;
1205
1206 return false;
1207}
1208
1209/// Duplicate and sink the given 'and' instruction into user blocks where it is
1210/// used in a compare to allow isel to generate better code for targets where
1211/// this operation can be combined.
1212///
1213/// Return true if any changes are made.
1214static bool sinkAndCmp0Expression(Instruction *AndI,
1215 const TargetLowering &TLI,
1216 SetOfInstrs &InsertedInsts) {
1217 // Double-check that we're not trying to optimize an instruction that was
1218 // already optimized by some other part of this pass.
1219 assert(!InsertedInsts.count(AndI) &&(static_cast <bool> (!InsertedInsts.count(AndI) &&
"Attempting to optimize already optimized and instruction") ?
void (0) : __assert_fail ("!InsertedInsts.count(AndI) && \"Attempting to optimize already optimized and instruction\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1220, __extension__ __PRETTY_FUNCTION__))
1220 "Attempting to optimize already optimized and instruction")(static_cast <bool> (!InsertedInsts.count(AndI) &&
"Attempting to optimize already optimized and instruction") ?
void (0) : __assert_fail ("!InsertedInsts.count(AndI) && \"Attempting to optimize already optimized and instruction\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1220, __extension__ __PRETTY_FUNCTION__))
;
1221 (void) InsertedInsts;
1222
1223 // Nothing to do for single use in same basic block.
1224 if (AndI->hasOneUse() &&
1225 AndI->getParent() == cast<Instruction>(*AndI->user_begin())->getParent())
1226 return false;
1227
1228 // Try to avoid cases where sinking/duplicating is likely to increase register
1229 // pressure.
1230 if (!isa<ConstantInt>(AndI->getOperand(0)) &&
1231 !isa<ConstantInt>(AndI->getOperand(1)) &&
1232 AndI->getOperand(0)->hasOneUse() && AndI->getOperand(1)->hasOneUse())
1233 return false;
1234
1235 for (auto *U : AndI->users()) {
1236 Instruction *User = cast<Instruction>(U);
1237
1238 // Only sink for and mask feeding icmp with 0.
1239 if (!isa<ICmpInst>(User))
1240 return false;
1241
1242 auto *CmpC = dyn_cast<ConstantInt>(User->getOperand(1));
1243 if (!CmpC || !CmpC->isZero())
1244 return false;
1245 }
1246
1247 if (!TLI.isMaskAndCmp0FoldingBeneficial(*AndI))
1248 return false;
1249
1250 DEBUG(dbgs() << "found 'and' feeding only icmp 0;\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "found 'and' feeding only icmp 0;\n"
; } } while (false)
;
1251 DEBUG(AndI->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { AndI->getParent()->dump(); } } while
(false)
;
1252
1253 // Push the 'and' into the same block as the icmp 0. There should only be
1254 // one (icmp (and, 0)) in each block, since CSE/GVN should have removed any
1255 // others, so we don't need to keep track of which BBs we insert into.
1256 for (Value::user_iterator UI = AndI->user_begin(), E = AndI->user_end();
1257 UI != E; ) {
1258 Use &TheUse = UI.getUse();
1259 Instruction *User = cast<Instruction>(*UI);
1260
1261 // Preincrement use iterator so we don't invalidate it.
1262 ++UI;
1263
1264 DEBUG(dbgs() << "sinking 'and' use: " << *User << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "sinking 'and' use: " <<
*User << "\n"; } } while (false)
;
1265
1266 // Keep the 'and' in the same place if the use is already in the same block.
1267 Instruction *InsertPt =
1268 User->getParent() == AndI->getParent() ? AndI : User;
1269 Instruction *InsertedAnd =
1270 BinaryOperator::Create(Instruction::And, AndI->getOperand(0),
1271 AndI->getOperand(1), "", InsertPt);
1272 // Propagate the debug info.
1273 InsertedAnd->setDebugLoc(AndI->getDebugLoc());
1274
1275 // Replace a use of the 'and' with a use of the new 'and'.
1276 TheUse = InsertedAnd;
1277 ++NumAndUses;
1278 DEBUG(User->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { User->getParent()->dump(); } } while
(false)
;
1279 }
1280
1281 // We removed all uses, nuke the and.
1282 AndI->eraseFromParent();
1283 return true;
1284}
1285
1286/// Check if the candidates could be combined with a shift instruction, which
1287/// includes:
1288/// 1. Truncate instruction
1289/// 2. And instruction and the imm is a mask of the low bits:
1290/// imm & (imm+1) == 0
1291static bool isExtractBitsCandidateUse(Instruction *User) {
1292 if (!isa<TruncInst>(User)) {
1293 if (User->getOpcode() != Instruction::And ||
1294 !isa<ConstantInt>(User->getOperand(1)))
1295 return false;
1296
1297 const APInt &Cimm = cast<ConstantInt>(User->getOperand(1))->getValue();
1298
1299 if ((Cimm & (Cimm + 1)).getBoolValue())
1300 return false;
1301 }
1302 return true;
1303}
1304
1305/// Sink both shift and truncate instruction to the use of truncate's BB.
1306static bool
1307SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI,
1308 DenseMap<BasicBlock *, BinaryOperator *> &InsertedShifts,
1309 const TargetLowering &TLI, const DataLayout &DL) {
1310 BasicBlock *UserBB = User->getParent();
1311 DenseMap<BasicBlock *, CastInst *> InsertedTruncs;
1312 TruncInst *TruncI = dyn_cast<TruncInst>(User);
1313 bool MadeChange = false;
1314
1315 for (Value::user_iterator TruncUI = TruncI->user_begin(),
1316 TruncE = TruncI->user_end();
1317 TruncUI != TruncE;) {
1318
1319 Use &TruncTheUse = TruncUI.getUse();
1320 Instruction *TruncUser = cast<Instruction>(*TruncUI);
1321 // Preincrement use iterator so we don't invalidate it.
1322
1323 ++TruncUI;
1324
1325 int ISDOpcode = TLI.InstructionOpcodeToISD(TruncUser->getOpcode());
1326 if (!ISDOpcode)
1327 continue;
1328
1329 // If the use is actually a legal node, there will not be an
1330 // implicit truncate.
1331 // FIXME: always querying the result type is just an
1332 // approximation; some nodes' legality is determined by the
1333 // operand or other means. There's no good way to find out though.
1334 if (TLI.isOperationLegalOrCustom(
1335 ISDOpcode, TLI.getValueType(DL, TruncUser->getType(), true)))
1336 continue;
1337
1338 // Don't bother for PHI nodes.
1339 if (isa<PHINode>(TruncUser))
1340 continue;
1341
1342 BasicBlock *TruncUserBB = TruncUser->getParent();
1343
1344 if (UserBB == TruncUserBB)
1345 continue;
1346
1347 BinaryOperator *&InsertedShift = InsertedShifts[TruncUserBB];
1348 CastInst *&InsertedTrunc = InsertedTruncs[TruncUserBB];
1349
1350 if (!InsertedShift && !InsertedTrunc) {
1351 BasicBlock::iterator InsertPt = TruncUserBB->getFirstInsertionPt();
1352 assert(InsertPt != TruncUserBB->end())(static_cast <bool> (InsertPt != TruncUserBB->end())
? void (0) : __assert_fail ("InsertPt != TruncUserBB->end()"
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1352, __extension__ __PRETTY_FUNCTION__))
;
1353 // Sink the shift
1354 if (ShiftI->getOpcode() == Instruction::AShr)
1355 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1356 "", &*InsertPt);
1357 else
1358 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1359 "", &*InsertPt);
1360
1361 // Sink the trunc
1362 BasicBlock::iterator TruncInsertPt = TruncUserBB->getFirstInsertionPt();
1363 TruncInsertPt++;
1364 assert(TruncInsertPt != TruncUserBB->end())(static_cast <bool> (TruncInsertPt != TruncUserBB->end
()) ? void (0) : __assert_fail ("TruncInsertPt != TruncUserBB->end()"
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1364, __extension__ __PRETTY_FUNCTION__))
;
1365
1366 InsertedTrunc = CastInst::Create(TruncI->getOpcode(), InsertedShift,
1367 TruncI->getType(), "", &*TruncInsertPt);
1368
1369 MadeChange = true;
1370
1371 TruncTheUse = InsertedTrunc;
1372 }
1373 }
1374 return MadeChange;
1375}
1376
1377/// Sink the shift *right* instruction into user blocks if the uses could
1378/// potentially be combined with this shift instruction and generate BitExtract
1379/// instruction. It will only be applied if the architecture supports BitExtract
1380/// instruction. Here is an example:
1381/// BB1:
1382/// %x.extract.shift = lshr i64 %arg1, 32
1383/// BB2:
1384/// %x.extract.trunc = trunc i64 %x.extract.shift to i16
1385/// ==>
1386///
1387/// BB2:
1388/// %x.extract.shift.1 = lshr i64 %arg1, 32
1389/// %x.extract.trunc = trunc i64 %x.extract.shift.1 to i16
1390///
1391/// CodeGen will recoginze the pattern in BB2 and generate BitExtract
1392/// instruction.
1393/// Return true if any changes are made.
1394static bool OptimizeExtractBits(BinaryOperator *ShiftI, ConstantInt *CI,
1395 const TargetLowering &TLI,
1396 const DataLayout &DL) {
1397 BasicBlock *DefBB = ShiftI->getParent();
1398
1399 /// Only insert instructions in each block once.
1400 DenseMap<BasicBlock *, BinaryOperator *> InsertedShifts;
1401
1402 bool shiftIsLegal = TLI.isTypeLegal(TLI.getValueType(DL, ShiftI->getType()));
1403
1404 bool MadeChange = false;
1405 for (Value::user_iterator UI = ShiftI->user_begin(), E = ShiftI->user_end();
1406 UI != E;) {
1407 Use &TheUse = UI.getUse();
1408 Instruction *User = cast<Instruction>(*UI);
1409 // Preincrement use iterator so we don't invalidate it.
1410 ++UI;
1411
1412 // Don't bother for PHI nodes.
1413 if (isa<PHINode>(User))
1414 continue;
1415
1416 if (!isExtractBitsCandidateUse(User))
1417 continue;
1418
1419 BasicBlock *UserBB = User->getParent();
1420
1421 if (UserBB == DefBB) {
1422 // If the shift and truncate instruction are in the same BB. The use of
1423 // the truncate(TruncUse) may still introduce another truncate if not
1424 // legal. In this case, we would like to sink both shift and truncate
1425 // instruction to the BB of TruncUse.
1426 // for example:
1427 // BB1:
1428 // i64 shift.result = lshr i64 opnd, imm
1429 // trunc.result = trunc shift.result to i16
1430 //
1431 // BB2:
1432 // ----> We will have an implicit truncate here if the architecture does
1433 // not have i16 compare.
1434 // cmp i16 trunc.result, opnd2
1435 //
1436 if (isa<TruncInst>(User) && shiftIsLegal
1437 // If the type of the truncate is legal, no trucate will be
1438 // introduced in other basic blocks.
1439 &&
1440 (!TLI.isTypeLegal(TLI.getValueType(DL, User->getType()))))
1441 MadeChange =
1442 SinkShiftAndTruncate(ShiftI, User, CI, InsertedShifts, TLI, DL);
1443
1444 continue;
1445 }
1446 // If we have already inserted a shift into this block, use it.
1447 BinaryOperator *&InsertedShift = InsertedShifts[UserBB];
1448
1449 if (!InsertedShift) {
1450 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
1451 assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
(0) : __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1451, __extension__ __PRETTY_FUNCTION__))
;
1452
1453 if (ShiftI->getOpcode() == Instruction::AShr)
1454 InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
1455 "", &*InsertPt);
1456 else
1457 InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
1458 "", &*InsertPt);
1459
1460 MadeChange = true;
1461 }
1462
1463 // Replace a use of the shift with a use of the new shift.
1464 TheUse = InsertedShift;
1465 }
1466
1467 // If we removed all uses, nuke the shift.
1468 if (ShiftI->use_empty())
1469 ShiftI->eraseFromParent();
1470
1471 return MadeChange;
1472}
1473
1474/// If counting leading or trailing zeros is an expensive operation and a zero
1475/// input is defined, add a check for zero to avoid calling the intrinsic.
1476///
1477/// We want to transform:
1478/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 false)
1479///
1480/// into:
1481/// entry:
1482/// %cmpz = icmp eq i64 %A, 0
1483/// br i1 %cmpz, label %cond.end, label %cond.false
1484/// cond.false:
1485/// %z = call i64 @llvm.cttz.i64(i64 %A, i1 true)
1486/// br label %cond.end
1487/// cond.end:
1488/// %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ]
1489///
1490/// If the transform is performed, return true and set ModifiedDT to true.
1491static bool despeculateCountZeros(IntrinsicInst *CountZeros,
1492 const TargetLowering *TLI,
1493 const DataLayout *DL,
1494 bool &ModifiedDT) {
1495 if (!TLI || !DL)
1496 return false;
1497
1498 // If a zero input is undefined, it doesn't make sense to despeculate that.
1499 if (match(CountZeros->getOperand(1), m_One()))
1500 return false;
1501
1502 // If it's cheap to speculate, there's nothing to do.
1503 auto IntrinsicID = CountZeros->getIntrinsicID();
1504 if ((IntrinsicID == Intrinsic::cttz && TLI->isCheapToSpeculateCttz()) ||
1505 (IntrinsicID == Intrinsic::ctlz && TLI->isCheapToSpeculateCtlz()))
1506 return false;
1507
1508 // Only handle legal scalar cases. Anything else requires too much work.
1509 Type *Ty = CountZeros->getType();
1510 unsigned SizeInBits = Ty->getPrimitiveSizeInBits();
1511 if (Ty->isVectorTy() || SizeInBits > DL->getLargestLegalIntTypeSizeInBits())
1512 return false;
1513
1514 // The intrinsic will be sunk behind a compare against zero and branch.
1515 BasicBlock *StartBlock = CountZeros->getParent();
1516 BasicBlock *CallBlock = StartBlock->splitBasicBlock(CountZeros, "cond.false");
1517
1518 // Create another block after the count zero intrinsic. A PHI will be added
1519 // in this block to select the result of the intrinsic or the bit-width
1520 // constant if the input to the intrinsic is zero.
1521 BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(CountZeros));
1522 BasicBlock *EndBlock = CallBlock->splitBasicBlock(SplitPt, "cond.end");
1523
1524 // Set up a builder to create a compare, conditional branch, and PHI.
1525 IRBuilder<> Builder(CountZeros->getContext());
1526 Builder.SetInsertPoint(StartBlock->getTerminator());
1527 Builder.SetCurrentDebugLocation(CountZeros->getDebugLoc());
1528
1529 // Replace the unconditional branch that was created by the first split with
1530 // a compare against zero and a conditional branch.
1531 Value *Zero = Constant::getNullValue(Ty);
1532 Value *Cmp = Builder.CreateICmpEQ(CountZeros->getOperand(0), Zero, "cmpz");
1533 Builder.CreateCondBr(Cmp, EndBlock, CallBlock);
1534 StartBlock->getTerminator()->eraseFromParent();
1535
1536 // Create a PHI in the end block to select either the output of the intrinsic
1537 // or the bit width of the operand.
1538 Builder.SetInsertPoint(&EndBlock->front());
1539 PHINode *PN = Builder.CreatePHI(Ty, 2, "ctz");
1540 CountZeros->replaceAllUsesWith(PN);
1541 Value *BitWidth = Builder.getInt(APInt(SizeInBits, SizeInBits));
1542 PN->addIncoming(BitWidth, StartBlock);
1543 PN->addIncoming(CountZeros, CallBlock);
1544
1545 // We are explicitly handling the zero case, so we can set the intrinsic's
1546 // undefined zero argument to 'true'. This will also prevent reprocessing the
1547 // intrinsic; we only despeculate when a zero input is defined.
1548 CountZeros->setArgOperand(1, Builder.getTrue());
1549 ModifiedDT = true;
1550 return true;
1551}
1552
1553bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool &ModifiedDT) {
1554 BasicBlock *BB = CI->getParent();
1555
1556 // Lower inline assembly if we can.
1557 // If we found an inline asm expession, and if the target knows how to
1558 // lower it to normal LLVM code, do so now.
1559 if (TLI && isa<InlineAsm>(CI->getCalledValue())) {
1560 if (TLI->ExpandInlineAsm(CI)) {
1561 // Avoid invalidating the iterator.
1562 CurInstIterator = BB->begin();
1563 // Avoid processing instructions out of order, which could cause
1564 // reuse before a value is defined.
1565 SunkAddrs.clear();
1566 return true;
1567 }
1568 // Sink address computing for memory operands into the block.
1569 if (optimizeInlineAsmInst(CI))
1570 return true;
1571 }
1572
1573 // Align the pointer arguments to this call if the target thinks it's a good
1574 // idea
1575 unsigned MinSize, PrefAlign;
1576 if (TLI && TLI->shouldAlignPointerArgs(CI, MinSize, PrefAlign)) {
1577 for (auto &Arg : CI->arg_operands()) {
1578 // We want to align both objects whose address is used directly and
1579 // objects whose address is used in casts and GEPs, though it only makes
1580 // sense for GEPs if the offset is a multiple of the desired alignment and
1581 // if size - offset meets the size threshold.
1582 if (!Arg->getType()->isPointerTy())
1583 continue;
1584 APInt Offset(DL->getIndexSizeInBits(
1585 cast<PointerType>(Arg->getType())->getAddressSpace()),
1586 0);
1587 Value *Val = Arg->stripAndAccumulateInBoundsConstantOffsets(*DL, Offset);
1588 uint64_t Offset2 = Offset.getLimitedValue();
1589 if ((Offset2 & (PrefAlign-1)) != 0)
1590 continue;
1591 AllocaInst *AI;
1592 if ((AI = dyn_cast<AllocaInst>(Val)) && AI->getAlignment() < PrefAlign &&
1593 DL->getTypeAllocSize(AI->getAllocatedType()) >= MinSize + Offset2)
1594 AI->setAlignment(PrefAlign);
1595 // Global variables can only be aligned if they are defined in this
1596 // object (i.e. they are uniquely initialized in this object), and
1597 // over-aligning global variables that have an explicit section is
1598 // forbidden.
1599 GlobalVariable *GV;
1600 if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() &&
1601 GV->getPointerAlignment(*DL) < PrefAlign &&
1602 DL->getTypeAllocSize(GV->getValueType()) >=
1603 MinSize + Offset2)
1604 GV->setAlignment(PrefAlign);
1605 }
1606 // If this is a memcpy (or similar) then we may be able to improve the
1607 // alignment
1608 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(CI)) {
1609 unsigned DestAlign = getKnownAlignment(MI->getDest(), *DL);
1610 if (DestAlign > MI->getDestAlignment())
1611 MI->setDestAlignment(DestAlign);
1612 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
1613 unsigned SrcAlign = getKnownAlignment(MTI->getSource(), *DL);
1614 if (SrcAlign > MTI->getSourceAlignment())
1615 MTI->setSourceAlignment(SrcAlign);
1616 }
1617 }
1618 }
1619
1620 // If we have a cold call site, try to sink addressing computation into the
1621 // cold block. This interacts with our handling for loads and stores to
1622 // ensure that we can fold all uses of a potential addressing computation
1623 // into their uses. TODO: generalize this to work over profiling data
1624 if (!OptSize && CI->hasFnAttr(Attribute::Cold))
1625 for (auto &Arg : CI->arg_operands()) {
1626 if (!Arg->getType()->isPointerTy())
1627 continue;
1628 unsigned AS = Arg->getType()->getPointerAddressSpace();
1629 return optimizeMemoryInst(CI, Arg, Arg->getType(), AS);
1630 }
1631
1632 IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
1633 if (II) {
1634 switch (II->getIntrinsicID()) {
1635 default: break;
1636 case Intrinsic::objectsize: {
1637 // Lower all uses of llvm.objectsize.*
1638 ConstantInt *RetVal =
1639 lowerObjectSizeCall(II, *DL, TLInfo, /*MustSucceed=*/true);
1640 // Substituting this can cause recursive simplifications, which can
1641 // invalidate our iterator. Use a WeakTrackingVH to hold onto it in case
1642 // this
1643 // happens.
1644 Value *CurValue = &*CurInstIterator;
1645 WeakTrackingVH IterHandle(CurValue);
1646
1647 replaceAndRecursivelySimplify(CI, RetVal, TLInfo, nullptr);
1648
1649 // If the iterator instruction was recursively deleted, start over at the
1650 // start of the block.
1651 if (IterHandle != CurValue) {
1652 CurInstIterator = BB->begin();
1653 SunkAddrs.clear();
1654 }
1655 return true;
1656 }
1657 case Intrinsic::aarch64_stlxr:
1658 case Intrinsic::aarch64_stxr: {
1659 ZExtInst *ExtVal = dyn_cast<ZExtInst>(CI->getArgOperand(0));
1660 if (!ExtVal || !ExtVal->hasOneUse() ||
1661 ExtVal->getParent() == CI->getParent())
1662 return false;
1663 // Sink a zext feeding stlxr/stxr before it, so it can be folded into it.
1664 ExtVal->moveBefore(CI);
1665 // Mark this instruction as "inserted by CGP", so that other
1666 // optimizations don't touch it.
1667 InsertedInsts.insert(ExtVal);
1668 return true;
1669 }
1670 case Intrinsic::invariant_group_barrier:
1671 II->replaceAllUsesWith(II->getArgOperand(0));
1672 II->eraseFromParent();
1673 return true;
1674
1675 case Intrinsic::cttz:
1676 case Intrinsic::ctlz:
1677 // If counting zeros is expensive, try to avoid it.
1678 return despeculateCountZeros(II, TLI, DL, ModifiedDT);
1679 }
1680
1681 if (TLI) {
1682 SmallVector<Value*, 2> PtrOps;
1683 Type *AccessTy;
1684 if (TLI->getAddrModeArguments(II, PtrOps, AccessTy))
1685 while (!PtrOps.empty()) {
1686 Value *PtrVal = PtrOps.pop_back_val();
1687 unsigned AS = PtrVal->getType()->getPointerAddressSpace();
1688 if (optimizeMemoryInst(II, PtrVal, AccessTy, AS))
1689 return true;
1690 }
1691 }
1692 }
1693
1694 // From here on out we're working with named functions.
1695 if (!CI->getCalledFunction()) return false;
1696
1697 // Lower all default uses of _chk calls. This is very similar
1698 // to what InstCombineCalls does, but here we are only lowering calls
1699 // to fortified library functions (e.g. __memcpy_chk) that have the default
1700 // "don't know" as the objectsize. Anything else should be left alone.
1701 FortifiedLibCallSimplifier Simplifier(TLInfo, true);
1702 if (Value *V = Simplifier.optimizeCall(CI)) {
1703 CI->replaceAllUsesWith(V);
1704 CI->eraseFromParent();
1705 return true;
1706 }
1707
1708 return false;
1709}
1710
1711/// Look for opportunities to duplicate return instructions to the predecessor
1712/// to enable tail call optimizations. The case it is currently looking for is:
1713/// @code
1714/// bb0:
1715/// %tmp0 = tail call i32 @f0()
1716/// br label %return
1717/// bb1:
1718/// %tmp1 = tail call i32 @f1()
1719/// br label %return
1720/// bb2:
1721/// %tmp2 = tail call i32 @f2()
1722/// br label %return
1723/// return:
1724/// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
1725/// ret i32 %retval
1726/// @endcode
1727///
1728/// =>
1729///
1730/// @code
1731/// bb0:
1732/// %tmp0 = tail call i32 @f0()
1733/// ret i32 %tmp0
1734/// bb1:
1735/// %tmp1 = tail call i32 @f1()
1736/// ret i32 %tmp1
1737/// bb2:
1738/// %tmp2 = tail call i32 @f2()
1739/// ret i32 %tmp2
1740/// @endcode
1741bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB) {
1742 if (!TLI)
1743 return false;
1744
1745 ReturnInst *RetI = dyn_cast<ReturnInst>(BB->getTerminator());
1746 if (!RetI)
1747 return false;
1748
1749 PHINode *PN = nullptr;
1750 BitCastInst *BCI = nullptr;
1751 Value *V = RetI->getReturnValue();
1752 if (V) {
1753 BCI = dyn_cast<BitCastInst>(V);
1754 if (BCI)
1755 V = BCI->getOperand(0);
1756
1757 PN = dyn_cast<PHINode>(V);
1758 if (!PN)
1759 return false;
1760 }
1761
1762 if (PN && PN->getParent() != BB)
1763 return false;
1764
1765 // Make sure there are no instructions between the PHI and return, or that the
1766 // return is the first instruction in the block.
1767 if (PN) {
1768 BasicBlock::iterator BI = BB->begin();
1769 do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
1770 if (&*BI == BCI)
1771 // Also skip over the bitcast.
1772 ++BI;
1773 if (&*BI != RetI)
1774 return false;
1775 } else {
1776 BasicBlock::iterator BI = BB->begin();
1777 while (isa<DbgInfoIntrinsic>(BI)) ++BI;
1778 if (&*BI != RetI)
1779 return false;
1780 }
1781
1782 /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
1783 /// call.
1784 const Function *F = BB->getParent();
1785 SmallVector<CallInst*, 4> TailCalls;
1786 if (PN) {
1787 for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
1788 CallInst *CI = dyn_cast<CallInst>(PN->getIncomingValue(I));
1789 // Make sure the phi value is indeed produced by the tail call.
1790 if (CI && CI->hasOneUse() && CI->getParent() == PN->getIncomingBlock(I) &&
1791 TLI->mayBeEmittedAsTailCall(CI) &&
1792 attributesPermitTailCall(F, CI, RetI, *TLI))
1793 TailCalls.push_back(CI);
1794 }
1795 } else {
1796 SmallPtrSet<BasicBlock*, 4> VisitedBBs;
1797 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1798 if (!VisitedBBs.insert(*PI).second)
1799 continue;
1800
1801 BasicBlock::InstListType &InstList = (*PI)->getInstList();
1802 BasicBlock::InstListType::reverse_iterator RI = InstList.rbegin();
1803 BasicBlock::InstListType::reverse_iterator RE = InstList.rend();
1804 do { ++RI; } while (RI != RE && isa<DbgInfoIntrinsic>(&*RI));
1805 if (RI == RE)
1806 continue;
1807
1808 CallInst *CI = dyn_cast<CallInst>(&*RI);
1809 if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI) &&
1810 attributesPermitTailCall(F, CI, RetI, *TLI))
1811 TailCalls.push_back(CI);
1812 }
1813 }
1814
1815 bool Changed = false;
1816 for (unsigned i = 0, e = TailCalls.size(); i != e; ++i) {
1817 CallInst *CI = TailCalls[i];
1818 CallSite CS(CI);
1819
1820 // Conservatively require the attributes of the call to match those of the
1821 // return. Ignore noalias because it doesn't affect the call sequence.
1822 AttributeList CalleeAttrs = CS.getAttributes();
1823 if (AttrBuilder(CalleeAttrs, AttributeList::ReturnIndex)
1824 .removeAttribute(Attribute::NoAlias) !=
1825 AttrBuilder(CalleeAttrs, AttributeList::ReturnIndex)
1826 .removeAttribute(Attribute::NoAlias))
1827 continue;
1828
1829 // Make sure the call instruction is followed by an unconditional branch to
1830 // the return block.
1831 BasicBlock *CallBB = CI->getParent();
1832 BranchInst *BI = dyn_cast<BranchInst>(CallBB->getTerminator());
1833 if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
1834 continue;
1835
1836 // Duplicate the return into CallBB.
1837 (void)FoldReturnIntoUncondBranch(RetI, BB, CallBB);
1838 ModifiedDT = Changed = true;
1839 ++NumRetsDup;
1840 }
1841
1842 // If we eliminated all predecessors of the block, delete the block now.
1843 if (Changed && !BB->hasAddressTaken() && pred_begin(BB) == pred_end(BB))
1844 BB->eraseFromParent();
1845
1846 return Changed;
1847}
1848
1849//===----------------------------------------------------------------------===//
1850// Memory Optimization
1851//===----------------------------------------------------------------------===//
1852
1853namespace {
1854
1855/// This is an extended version of TargetLowering::AddrMode
1856/// which holds actual Value*'s for register values.
1857struct ExtAddrMode : public TargetLowering::AddrMode {
1858 Value *BaseReg = nullptr;
1859 Value *ScaledReg = nullptr;
1860 Value *OriginalValue = nullptr;
1861
1862 enum FieldName {
1863 NoField = 0x00,
1864 BaseRegField = 0x01,
1865 BaseGVField = 0x02,
1866 BaseOffsField = 0x04,
1867 ScaledRegField = 0x08,
1868 ScaleField = 0x10,
1869 MultipleFields = 0xff
1870 };
1871
1872 ExtAddrMode() = default;
1873
1874 void print(raw_ostream &OS) const;
1875 void dump() const;
1876
1877 FieldName compare(const ExtAddrMode &other) {
1878 // First check that the types are the same on each field, as differing types
1879 // is something we can't cope with later on.
1880 if (BaseReg && other.BaseReg &&
1881 BaseReg->getType() != other.BaseReg->getType())
1882 return MultipleFields;
1883 if (BaseGV && other.BaseGV &&
1884 BaseGV->getType() != other.BaseGV->getType())
1885 return MultipleFields;
1886 if (ScaledReg && other.ScaledReg &&
1887 ScaledReg->getType() != other.ScaledReg->getType())
1888 return MultipleFields;
1889
1890 // Check each field to see if it differs.
1891 unsigned Result = NoField;
1892 if (BaseReg != other.BaseReg)
1893 Result |= BaseRegField;
1894 if (BaseGV != other.BaseGV)
1895 Result |= BaseGVField;
1896 if (BaseOffs != other.BaseOffs)
1897 Result |= BaseOffsField;
1898 if (ScaledReg != other.ScaledReg)
1899 Result |= ScaledRegField;
1900 // Don't count 0 as being a different scale, because that actually means
1901 // unscaled (which will already be counted by having no ScaledReg).
1902 if (Scale && other.Scale && Scale != other.Scale)
1903 Result |= ScaleField;
1904
1905 if (countPopulation(Result) > 1)
1906 return MultipleFields;
1907 else
1908 return static_cast<FieldName>(Result);
1909 }
1910
1911 // An AddrMode is trivial if it involves no calculation i.e. it is just a base
1912 // with no offset.
1913 bool isTrivial() {
1914 // An AddrMode is (BaseGV + BaseReg + BaseOffs + ScaleReg * Scale) so it is
1915 // trivial if at most one of these terms is nonzero, except that BaseGV and
1916 // BaseReg both being zero actually means a null pointer value, which we
1917 // consider to be 'non-zero' here.
1918 return !BaseOffs && !Scale && !(BaseGV && BaseReg);
1919 }
1920
1921 Value *GetFieldAsValue(FieldName Field, Type *IntPtrTy) {
1922 switch (Field) {
1923 default:
1924 return nullptr;
1925 case BaseRegField:
1926 return BaseReg;
1927 case BaseGVField:
1928 return BaseGV;
1929 case ScaledRegField:
1930 return ScaledReg;
1931 case BaseOffsField:
1932 return ConstantInt::get(IntPtrTy, BaseOffs);
1933 }
1934 }
1935
1936 void SetCombinedField(FieldName Field, Value *V,
1937 const SmallVectorImpl<ExtAddrMode> &AddrModes) {
1938 switch (Field) {
1939 default:
1940 llvm_unreachable("Unhandled fields are expected to be rejected earlier")::llvm::llvm_unreachable_internal("Unhandled fields are expected to be rejected earlier"
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1940)
;
1941 break;
1942 case ExtAddrMode::BaseRegField:
1943 BaseReg = V;
1944 break;
1945 case ExtAddrMode::BaseGVField:
1946 // A combined BaseGV is an Instruction, not a GlobalValue, so it goes
1947 // in the BaseReg field.
1948 assert(BaseReg == nullptr)(static_cast <bool> (BaseReg == nullptr) ? void (0) : __assert_fail
("BaseReg == nullptr", "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1948, __extension__ __PRETTY_FUNCTION__))
;
1949 BaseReg = V;
1950 BaseGV = nullptr;
1951 break;
1952 case ExtAddrMode::ScaledRegField:
1953 ScaledReg = V;
1954 // If we have a mix of scaled and unscaled addrmodes then we want scale
1955 // to be the scale and not zero.
1956 if (!Scale)
1957 for (const ExtAddrMode &AM : AddrModes)
1958 if (AM.Scale) {
1959 Scale = AM.Scale;
1960 break;
1961 }
1962 break;
1963 case ExtAddrMode::BaseOffsField:
1964 // The offset is no longer a constant, so it goes in ScaledReg with a
1965 // scale of 1.
1966 assert(ScaledReg == nullptr)(static_cast <bool> (ScaledReg == nullptr) ? void (0) :
__assert_fail ("ScaledReg == nullptr", "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 1966, __extension__ __PRETTY_FUNCTION__))
;
1967 ScaledReg = V;
1968 Scale = 1;
1969 BaseOffs = 0;
1970 break;
1971 }
1972 }
1973};
1974
1975} // end anonymous namespace
1976
1977#ifndef NDEBUG
1978static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
1979 AM.print(OS);
1980 return OS;
1981}
1982#endif
1983
1984#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1985void ExtAddrMode::print(raw_ostream &OS) const {
1986 bool NeedPlus = false;
1987 OS << "[";
1988 if (BaseGV) {
1989 OS << (NeedPlus ? " + " : "")
1990 << "GV:";
1991 BaseGV->printAsOperand(OS, /*PrintType=*/false);
1992 NeedPlus = true;
1993 }
1994
1995 if (BaseOffs) {
1996 OS << (NeedPlus ? " + " : "")
1997 << BaseOffs;
1998 NeedPlus = true;
1999 }
2000
2001 if (BaseReg) {
2002 OS << (NeedPlus ? " + " : "")
2003 << "Base:";
2004 BaseReg->printAsOperand(OS, /*PrintType=*/false);
2005 NeedPlus = true;
2006 }
2007 if (Scale) {
2008 OS << (NeedPlus ? " + " : "")
2009 << Scale << "*";
2010 ScaledReg->printAsOperand(OS, /*PrintType=*/false);
2011 }
2012
2013 OS << ']';
2014}
2015
2016LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void ExtAddrMode::dump() const {
2017 print(dbgs());
2018 dbgs() << '\n';
2019}
2020#endif
2021
2022namespace {
2023
2024/// \brief This class provides transaction based operation on the IR.
2025/// Every change made through this class is recorded in the internal state and
2026/// can be undone (rollback) until commit is called.
2027class TypePromotionTransaction {
2028 /// \brief This represents the common interface of the individual transaction.
2029 /// Each class implements the logic for doing one specific modification on
2030 /// the IR via the TypePromotionTransaction.
2031 class TypePromotionAction {
2032 protected:
2033 /// The Instruction modified.
2034 Instruction *Inst;
2035
2036 public:
2037 /// \brief Constructor of the action.
2038 /// The constructor performs the related action on the IR.
2039 TypePromotionAction(Instruction *Inst) : Inst(Inst) {}
2040
2041 virtual ~TypePromotionAction() = default;
2042
2043 /// \brief Undo the modification done by this action.
2044 /// When this method is called, the IR must be in the same state as it was
2045 /// before this action was applied.
2046 /// \pre Undoing the action works if and only if the IR is in the exact same
2047 /// state as it was directly after this action was applied.
2048 virtual void undo() = 0;
2049
2050 /// \brief Advocate every change made by this action.
2051 /// When the results on the IR of the action are to be kept, it is important
2052 /// to call this function, otherwise hidden information may be kept forever.
2053 virtual void commit() {
2054 // Nothing to be done, this action is not doing anything.
2055 }
2056 };
2057
2058 /// \brief Utility to remember the position of an instruction.
2059 class InsertionHandler {
2060 /// Position of an instruction.
2061 /// Either an instruction:
2062 /// - Is the first in a basic block: BB is used.
2063 /// - Has a previous instructon: PrevInst is used.
2064 union {
2065 Instruction *PrevInst;
2066 BasicBlock *BB;
2067 } Point;
2068
2069 /// Remember whether or not the instruction had a previous instruction.
2070 bool HasPrevInstruction;
2071
2072 public:
2073 /// \brief Record the position of \p Inst.
2074 InsertionHandler(Instruction *Inst) {
2075 BasicBlock::iterator It = Inst->getIterator();
2076 HasPrevInstruction = (It != (Inst->getParent()->begin()));
2077 if (HasPrevInstruction)
2078 Point.PrevInst = &*--It;
2079 else
2080 Point.BB = Inst->getParent();
2081 }
2082
2083 /// \brief Insert \p Inst at the recorded position.
2084 void insert(Instruction *Inst) {
2085 if (HasPrevInstruction) {
2086 if (Inst->getParent())
2087 Inst->removeFromParent();
2088 Inst->insertAfter(Point.PrevInst);
2089 } else {
2090 Instruction *Position = &*Point.BB->getFirstInsertionPt();
2091 if (Inst->getParent())
2092 Inst->moveBefore(Position);
2093 else
2094 Inst->insertBefore(Position);
2095 }
2096 }
2097 };
2098
2099 /// \brief Move an instruction before another.
2100 class InstructionMoveBefore : public TypePromotionAction {
2101 /// Original position of the instruction.
2102 InsertionHandler Position;
2103
2104 public:
2105 /// \brief Move \p Inst before \p Before.
2106 InstructionMoveBefore(Instruction *Inst, Instruction *Before)
2107 : TypePromotionAction(Inst), Position(Inst) {
2108 DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Before << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: move: " << *
Inst << "\nbefore: " << *Before << "\n"; } }
while (false)
;
2109 Inst->moveBefore(Before);
2110 }
2111
2112 /// \brief Move the instruction back to its original position.
2113 void undo() override {
2114 DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: moveBefore: " <<
*Inst << "\n"; } } while (false)
;
2115 Position.insert(Inst);
2116 }
2117 };
2118
2119 /// \brief Set the operand of an instruction with a new value.
2120 class OperandSetter : public TypePromotionAction {
2121 /// Original operand of the instruction.
2122 Value *Origin;
2123
2124 /// Index of the modified instruction.
2125 unsigned Idx;
2126
2127 public:
2128 /// \brief Set \p Idx operand of \p Inst with \p NewVal.
2129 OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
2130 : TypePromotionAction(Inst), Idx(Idx) {
2131 DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
2132 << "for:" << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
2133 << "with:" << *NewVal << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
Idx << "\n" << "for:" << *Inst << "\n"
<< "with:" << *NewVal << "\n"; } } while (
false)
;
2134 Origin = Inst->getOperand(Idx);
2135 Inst->setOperand(Idx, NewVal);
2136 }
2137
2138 /// \brief Restore the original value of the instruction.
2139 void undo() override {
2140 DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
2141 << "for: " << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
2142 << "with: " << *Origin << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
Idx << "\n" << "for: " << *Inst << "\n"
<< "with: " << *Origin << "\n"; } } while (
false)
;
2143 Inst->setOperand(Idx, Origin);
2144 }
2145 };
2146
2147 /// \brief Hide the operands of an instruction.
2148 /// Do as if this instruction was not using any of its operands.
2149 class OperandsHider : public TypePromotionAction {
2150 /// The list of original operands.
2151 SmallVector<Value *, 4> OriginalValues;
2152
2153 public:
2154 /// \brief Remove \p Inst from the uses of the operands of \p Inst.
2155 OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
2156 DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: OperandsHider: " <<
*Inst << "\n"; } } while (false)
;
2157 unsigned NumOpnds = Inst->getNumOperands();
2158 OriginalValues.reserve(NumOpnds);
2159 for (unsigned It = 0; It < NumOpnds; ++It) {
2160 // Save the current operand.
2161 Value *Val = Inst->getOperand(It);
2162 OriginalValues.push_back(Val);
2163 // Set a dummy one.
2164 // We could use OperandSetter here, but that would imply an overhead
2165 // that we are not willing to pay.
2166 Inst->setOperand(It, UndefValue::get(Val->getType()));
2167 }
2168 }
2169
2170 /// \brief Restore the original list of uses.
2171 void undo() override {
2172 DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: OperandsHider: "
<< *Inst << "\n"; } } while (false)
;
2173 for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
2174 Inst->setOperand(It, OriginalValues[It]);
2175 }
2176 };
2177
2178 /// \brief Build a truncate instruction.
2179 class TruncBuilder : public TypePromotionAction {
2180 Value *Val;
2181
2182 public:
2183 /// \brief Build a truncate instruction of \p Opnd producing a \p Ty
2184 /// result.
2185 /// trunc Opnd to Ty.
2186 TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
2187 IRBuilder<> Builder(Opnd);
2188 Val = Builder.CreateTrunc(Opnd, Ty, "promoted");
2189 DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: TruncBuilder: " <<
*Val << "\n"; } } while (false)
;
2190 }
2191
2192 /// \brief Get the built value.
2193 Value *getBuiltValue() { return Val; }
2194
2195 /// \brief Remove the built instruction.
2196 void undo() override {
2197 DEBUG(dbgs() << "Undo: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: TruncBuilder: " <<
*Val << "\n"; } } while (false)
;
2198 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2199 IVal->eraseFromParent();
2200 }
2201 };
2202
2203 /// \brief Build a sign extension instruction.
2204 class SExtBuilder : public TypePromotionAction {
2205 Value *Val;
2206
2207 public:
2208 /// \brief Build a sign extension instruction of \p Opnd producing a \p Ty
2209 /// result.
2210 /// sext Opnd to Ty.
2211 SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2212 : TypePromotionAction(InsertPt) {
2213 IRBuilder<> Builder(InsertPt);
2214 Val = Builder.CreateSExt(Opnd, Ty, "promoted");
2215 DEBUG(dbgs() << "Do: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: SExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2216 }
2217
2218 /// \brief Get the built value.
2219 Value *getBuiltValue() { return Val; }
2220
2221 /// \brief Remove the built instruction.
2222 void undo() override {
2223 DEBUG(dbgs() << "Undo: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: SExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2224 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2225 IVal->eraseFromParent();
2226 }
2227 };
2228
2229 /// \brief Build a zero extension instruction.
2230 class ZExtBuilder : public TypePromotionAction {
2231 Value *Val;
2232
2233 public:
2234 /// \brief Build a zero extension instruction of \p Opnd producing a \p Ty
2235 /// result.
2236 /// zext Opnd to Ty.
2237 ZExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
2238 : TypePromotionAction(InsertPt) {
2239 IRBuilder<> Builder(InsertPt);
2240 Val = Builder.CreateZExt(Opnd, Ty, "promoted");
2241 DEBUG(dbgs() << "Do: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: ZExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2242 }
2243
2244 /// \brief Get the built value.
2245 Value *getBuiltValue() { return Val; }
2246
2247 /// \brief Remove the built instruction.
2248 void undo() override {
2249 DEBUG(dbgs() << "Undo: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: ZExtBuilder: " <<
*Val << "\n"; } } while (false)
;
2250 if (Instruction *IVal = dyn_cast<Instruction>(Val))
2251 IVal->eraseFromParent();
2252 }
2253 };
2254
2255 /// \brief Mutate an instruction to another type.
2256 class TypeMutator : public TypePromotionAction {
2257 /// Record the original type.
2258 Type *OrigTy;
2259
2260 public:
2261 /// \brief Mutate the type of \p Inst into \p NewTy.
2262 TypeMutator(Instruction *Inst, Type *NewTy)
2263 : TypePromotionAction(Inst), OrigTy(Inst->getType()) {
2264 DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
*Inst << " with " << *NewTy << "\n"; } } while
(false)
2265 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
*Inst << " with " << *NewTy << "\n"; } } while
(false)
;
2266 Inst->mutateType(NewTy);
2267 }
2268
2269 /// \brief Mutate the instruction back to its original type.
2270 void undo() override {
2271 DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
*Inst << " with " << *OrigTy << "\n"; } } while
(false)
2272 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
*Inst << " with " << *OrigTy << "\n"; } } while
(false)
;
2273 Inst->mutateType(OrigTy);
2274 }
2275 };
2276
2277 /// \brief Replace the uses of an instruction by another instruction.
2278 class UsesReplacer : public TypePromotionAction {
2279 /// Helper structure to keep track of the replaced uses.
2280 struct InstructionAndIdx {
2281 /// The instruction using the instruction.
2282 Instruction *Inst;
2283
2284 /// The index where this instruction is used for Inst.
2285 unsigned Idx;
2286
2287 InstructionAndIdx(Instruction *Inst, unsigned Idx)
2288 : Inst(Inst), Idx(Idx) {}
2289 };
2290
2291 /// Keep track of the original uses (pair Instruction, Index).
2292 SmallVector<InstructionAndIdx, 4> OriginalUses;
2293
2294 using use_iterator = SmallVectorImpl<InstructionAndIdx>::iterator;
2295
2296 public:
2297 /// \brief Replace all the use of \p Inst by \p New.
2298 UsesReplacer(Instruction *Inst, Value *New) : TypePromotionAction(Inst) {
2299 DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *Newdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
*Inst << " with " << *New << "\n"; } } while
(false)
2300 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
*Inst << " with " << *New << "\n"; } } while
(false)
;
2301 // Record the original uses.
2302 for (Use &U : Inst->uses()) {
2303 Instruction *UserI = cast<Instruction>(U.getUser());
2304 OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo()));
2305 }
2306 // Now, we can replace the uses.
2307 Inst->replaceAllUsesWith(New);
2308 }
2309
2310 /// \brief Reassign the original uses of Inst to Inst.
2311 void undo() override {
2312 DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: UsersReplacer: "
<< *Inst << "\n"; } } while (false)
;
2313 for (use_iterator UseIt = OriginalUses.begin(),
2314 EndIt = OriginalUses.end();
2315 UseIt != EndIt; ++UseIt) {
2316 UseIt->Inst->setOperand(UseIt->Idx, Inst);
2317 }
2318 }
2319 };
2320
2321 /// \brief Remove an instruction from the IR.
2322 class InstructionRemover : public TypePromotionAction {
2323 /// Original position of the instruction.
2324 InsertionHandler Inserter;
2325
2326 /// Helper structure to hide all the link to the instruction. In other
2327 /// words, this helps to do as if the instruction was removed.
2328 OperandsHider Hider;
2329
2330 /// Keep track of the uses replaced, if any.
2331 UsesReplacer *Replacer = nullptr;
2332
2333 /// Keep track of instructions removed.
2334 SetOfInstrs &RemovedInsts;
2335
2336 public:
2337 /// \brief Remove all reference of \p Inst and optinally replace all its
2338 /// uses with New.
2339 /// \p RemovedInsts Keep track of the instructions removed by this Action.
2340 /// \pre If !Inst->use_empty(), then New != nullptr
2341 InstructionRemover(Instruction *Inst, SetOfInstrs &RemovedInsts,
2342 Value *New = nullptr)
2343 : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
2344 RemovedInsts(RemovedInsts) {
2345 if (New)
2346 Replacer = new UsesReplacer(Inst, New);
2347 DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: InstructionRemover: "
<< *Inst << "\n"; } } while (false)
;
2348 RemovedInsts.insert(Inst);
2349 /// The instructions removed here will be freed after completing
2350 /// optimizeBlock() for all blocks as we need to keep track of the
2351 /// removed instructions during promotion.
2352 Inst->removeFromParent();
2353 }
2354
2355 ~InstructionRemover() override { delete Replacer; }
2356
2357 /// \brief Resurrect the instruction and reassign it to the proper uses if
2358 /// new value was provided when build this action.
2359 void undo() override {
2360 DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: InstructionRemover: "
<< *Inst << "\n"; } } while (false)
;
2361 Inserter.insert(Inst);
2362 if (Replacer)
2363 Replacer->undo();
2364 Hider.undo();
2365 RemovedInsts.erase(Inst);
2366 }
2367 };
2368
2369public:
2370 /// Restoration point.
2371 /// The restoration point is a pointer to an action instead of an iterator
2372 /// because the iterator may be invalidated but not the pointer.
2373 using ConstRestorationPt = const TypePromotionAction *;
2374
2375 TypePromotionTransaction(SetOfInstrs &RemovedInsts)
2376 : RemovedInsts(RemovedInsts) {}
2377
2378 /// Advocate every changes made in that transaction.
2379 void commit();
2380
2381 /// Undo all the changes made after the given point.
2382 void rollback(ConstRestorationPt Point);
2383
2384 /// Get the current restoration point.
2385 ConstRestorationPt getRestorationPoint() const;
2386
2387 /// \name API for IR modification with state keeping to support rollback.
2388 /// @{
2389 /// Same as Instruction::setOperand.
2390 void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);
2391
2392 /// Same as Instruction::eraseFromParent.
2393 void eraseInstruction(Instruction *Inst, Value *NewVal = nullptr);
2394
2395 /// Same as Value::replaceAllUsesWith.
2396 void replaceAllUsesWith(Instruction *Inst, Value *New);
2397
2398 /// Same as Value::mutateType.
2399 void mutateType(Instruction *Inst, Type *NewTy);
2400
2401 /// Same as IRBuilder::createTrunc.
2402 Value *createTrunc(Instruction *Opnd, Type *Ty);
2403
2404 /// Same as IRBuilder::createSExt.
2405 Value *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);
2406
2407 /// Same as IRBuilder::createZExt.
2408 Value *createZExt(Instruction *Inst, Value *Opnd, Type *Ty);
2409
2410 /// Same as Instruction::moveBefore.
2411 void moveBefore(Instruction *Inst, Instruction *Before);
2412 /// @}
2413
2414private:
2415 /// The ordered list of actions made so far.
2416 SmallVector<std::unique_ptr<TypePromotionAction>, 16> Actions;
2417
2418 using CommitPt = SmallVectorImpl<std::unique_ptr<TypePromotionAction>>::iterator;
2419
2420 SetOfInstrs &RemovedInsts;
2421};
2422
2423} // end anonymous namespace
2424
2425void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
2426 Value *NewVal) {
2427 Actions.push_back(llvm::make_unique<TypePromotionTransaction::OperandSetter>(
2428 Inst, Idx, NewVal));
2429}
2430
2431void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
2432 Value *NewVal) {
2433 Actions.push_back(
2434 llvm::make_unique<TypePromotionTransaction::InstructionRemover>(
2435 Inst, RemovedInsts, NewVal));
2436}
2437
2438void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
2439 Value *New) {
2440 Actions.push_back(
2441 llvm::make_unique<TypePromotionTransaction::UsesReplacer>(Inst, New));
2442}
2443
2444void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
2445 Actions.push_back(
2446 llvm::make_unique<TypePromotionTransaction::TypeMutator>(Inst, NewTy));
2447}
2448
2449Value *TypePromotionTransaction::createTrunc(Instruction *Opnd,
2450 Type *Ty) {
2451 std::unique_ptr<TruncBuilder> Ptr(new TruncBuilder(Opnd, Ty));
2452 Value *Val = Ptr->getBuiltValue();
2453 Actions.push_back(std::move(Ptr));
2454 return Val;
2455}
2456
2457Value *TypePromotionTransaction::createSExt(Instruction *Inst,
2458 Value *Opnd, Type *Ty) {
2459 std::unique_ptr<SExtBuilder> Ptr(new SExtBuilder(Inst, Opnd, Ty));
2460 Value *Val = Ptr->getBuiltValue();
2461 Actions.push_back(std::move(Ptr));
2462 return Val;
2463}
2464
2465Value *TypePromotionTransaction::createZExt(Instruction *Inst,
2466 Value *Opnd, Type *Ty) {
2467 std::unique_ptr<ZExtBuilder> Ptr(new ZExtBuilder(Inst, Opnd, Ty));
2468 Value *Val = Ptr->getBuiltValue();
2469 Actions.push_back(std::move(Ptr));
2470 return Val;
2471}
2472
2473void TypePromotionTransaction::moveBefore(Instruction *Inst,
2474 Instruction *Before) {
2475 Actions.push_back(
2476 llvm::make_unique<TypePromotionTransaction::InstructionMoveBefore>(
2477 Inst, Before));
2478}
2479
2480TypePromotionTransaction::ConstRestorationPt
2481TypePromotionTransaction::getRestorationPoint() const {
2482 return !Actions.empty() ? Actions.back().get() : nullptr;
2483}
2484
2485void TypePromotionTransaction::commit() {
2486 for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt;
2487 ++It)
2488 (*It)->commit();
2489 Actions.clear();
2490}
2491
2492void TypePromotionTransaction::rollback(
2493 TypePromotionTransaction::ConstRestorationPt Point) {
2494 while (!Actions.empty() && Point != Actions.back().get()) {
2495 std::unique_ptr<TypePromotionAction> Curr = Actions.pop_back_val();
2496 Curr->undo();
2497 }
2498}
2499
2500namespace {
2501
2502/// \brief A helper class for matching addressing modes.
2503///
2504/// This encapsulates the logic for matching the target-legal addressing modes.
2505class AddressingModeMatcher {
2506 SmallVectorImpl<Instruction*> &AddrModeInsts;
2507 const TargetLowering &TLI;
2508 const TargetRegisterInfo &TRI;
2509 const DataLayout &DL;
2510
2511 /// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
2512 /// the memory instruction that we're computing this address for.
2513 Type *AccessTy;
2514 unsigned AddrSpace;
2515 Instruction *MemoryInst;
2516
2517 /// This is the addressing mode that we're building up. This is
2518 /// part of the return value of this addressing mode matching stuff.
2519 ExtAddrMode &AddrMode;
2520
2521 /// The instructions inserted by other CodeGenPrepare optimizations.
2522 const SetOfInstrs &InsertedInsts;
2523
2524 /// A map from the instructions to their type before promotion.
2525 InstrToOrigTy &PromotedInsts;
2526
2527 /// The ongoing transaction where every action should be registered.
2528 TypePromotionTransaction &TPT;
2529
2530 /// This is set to true when we should not do profitability checks.
2531 /// When true, IsProfitableToFoldIntoAddressingMode always returns true.
2532 bool IgnoreProfitability;
2533
2534 AddressingModeMatcher(SmallVectorImpl<Instruction *> &AMI,
2535 const TargetLowering &TLI,
2536 const TargetRegisterInfo &TRI,
2537 Type *AT, unsigned AS,
2538 Instruction *MI, ExtAddrMode &AM,
2539 const SetOfInstrs &InsertedInsts,
2540 InstrToOrigTy &PromotedInsts,
2541 TypePromotionTransaction &TPT)
2542 : AddrModeInsts(AMI), TLI(TLI), TRI(TRI),
2543 DL(MI->getModule()->getDataLayout()), AccessTy(AT), AddrSpace(AS),
2544 MemoryInst(MI), AddrMode(AM), InsertedInsts(InsertedInsts),
2545 PromotedInsts(PromotedInsts), TPT(TPT) {
2546 IgnoreProfitability = false;
2547 }
2548
2549public:
2550 /// Find the maximal addressing mode that a load/store of V can fold,
2551 /// give an access type of AccessTy. This returns a list of involved
2552 /// instructions in AddrModeInsts.
2553 /// \p InsertedInsts The instructions inserted by other CodeGenPrepare
2554 /// optimizations.
2555 /// \p PromotedInsts maps the instructions to their type before promotion.
2556 /// \p The ongoing transaction where every action should be registered.
2557 static ExtAddrMode Match(Value *V, Type *AccessTy, unsigned AS,
2558 Instruction *MemoryInst,
2559 SmallVectorImpl<Instruction*> &AddrModeInsts,
2560 const TargetLowering &TLI,
2561 const TargetRegisterInfo &TRI,
2562 const SetOfInstrs &InsertedInsts,
2563 InstrToOrigTy &PromotedInsts,
2564 TypePromotionTransaction &TPT) {
2565 ExtAddrMode Result;
2566
2567 bool Success = AddressingModeMatcher(AddrModeInsts, TLI, TRI,
2568 AccessTy, AS,
2569 MemoryInst, Result, InsertedInsts,
2570 PromotedInsts, TPT).matchAddr(V, 0);
2571 (void)Success; assert(Success && "Couldn't select *anything*?")(static_cast <bool> (Success && "Couldn't select *anything*?"
) ? void (0) : __assert_fail ("Success && \"Couldn't select *anything*?\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 2571, __extension__ __PRETTY_FUNCTION__))
;
2572 return Result;
2573 }
2574
2575private:
2576 bool matchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
2577 bool matchAddr(Value *V, unsigned Depth);
2578 bool matchOperationAddr(User *Operation, unsigned Opcode, unsigned Depth,
2579 bool *MovedAway = nullptr);
2580 bool isProfitableToFoldIntoAddressingMode(Instruction *I,
2581 ExtAddrMode &AMBefore,
2582 ExtAddrMode &AMAfter);
2583 bool valueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
2584 bool isPromotionProfitable(unsigned NewCost, unsigned OldCost,
2585 Value *PromotedOperand) const;
2586};
2587
2588/// \brief Keep track of simplification of Phi nodes.
2589/// Accept the set of all phi nodes and erase phi node from this set
2590/// if it is simplified.
2591class SimplificationTracker {
2592 DenseMap<Value *, Value *> Storage;
2593 const SimplifyQuery &SQ;
2594 SmallPtrSetImpl<PHINode *> &AllPhiNodes;
2595 SmallPtrSetImpl<SelectInst *> &AllSelectNodes;
2596
2597public:
2598 SimplificationTracker(const SimplifyQuery &sq,
2599 SmallPtrSetImpl<PHINode *> &APN,
2600 SmallPtrSetImpl<SelectInst *> &ASN)
2601 : SQ(sq), AllPhiNodes(APN), AllSelectNodes(ASN) {}
2602
2603 Value *Get(Value *V) {
2604 do {
2605 auto SV = Storage.find(V);
2606 if (SV == Storage.end())
2607 return V;
2608 V = SV->second;
2609 } while (true);
2610 }
2611
2612 Value *Simplify(Value *Val) {
2613 SmallVector<Value *, 32> WorkList;
2614 SmallPtrSet<Value *, 32> Visited;
2615 WorkList.push_back(Val);
2616 while (!WorkList.empty()) {
2617 auto P = WorkList.pop_back_val();
2618 if (!Visited.insert(P).second)
2619 continue;
2620 if (auto *PI = dyn_cast<Instruction>(P))
2621 if (Value *V = SimplifyInstruction(cast<Instruction>(PI), SQ)) {
2622 for (auto *U : PI->users())
2623 WorkList.push_back(cast<Value>(U));
2624 Put(PI, V);
2625 PI->replaceAllUsesWith(V);
2626 if (auto *PHI = dyn_cast<PHINode>(PI))
2627 AllPhiNodes.erase(PHI);
2628 if (auto *Select = dyn_cast<SelectInst>(PI))
2629 AllSelectNodes.erase(Select);
2630 PI->eraseFromParent();
2631 }
2632 }
2633 return Get(Val);
2634 }
2635
2636 void Put(Value *From, Value *To) {
2637 Storage.insert({ From, To });
2638 }
2639};
2640
2641/// \brief A helper class for combining addressing modes.
2642class AddressingModeCombiner {
2643 typedef std::pair<Value *, BasicBlock *> ValueInBB;
2644 typedef DenseMap<ValueInBB, Value *> FoldAddrToValueMapping;
2645 typedef std::pair<PHINode *, PHINode *> PHIPair;
2646
2647private:
2648 /// The addressing modes we've collected.
2649 SmallVector<ExtAddrMode, 16> AddrModes;
2650
2651 /// The field in which the AddrModes differ, when we have more than one.
2652 ExtAddrMode::FieldName DifferentField = ExtAddrMode::NoField;
2653
2654 /// Are the AddrModes that we have all just equal to their original values?
2655 bool AllAddrModesTrivial = true;
2656
2657 /// Common Type for all different fields in addressing modes.
2658 Type *CommonType;
2659
2660 /// SimplifyQuery for simplifyInstruction utility.
2661 const SimplifyQuery &SQ;
2662
2663 /// Original Address.
2664 ValueInBB Original;
2665
2666public:
2667 AddressingModeCombiner(const SimplifyQuery &_SQ, ValueInBB OriginalValue)
2668 : CommonType(nullptr), SQ(_SQ), Original(OriginalValue) {}
2669
2670 /// \brief Get the combined AddrMode
2671 const ExtAddrMode &getAddrMode() const {
2672 return AddrModes[0];
2673 }
2674
2675 /// \brief Add a new AddrMode if it's compatible with the AddrModes we already
2676 /// have.
2677 /// \return True iff we succeeded in doing so.
2678 bool addNewAddrMode(ExtAddrMode &NewAddrMode) {
2679 // Take note of if we have any non-trivial AddrModes, as we need to detect
2680 // when all AddrModes are trivial as then we would introduce a phi or select
2681 // which just duplicates what's already there.
2682 AllAddrModesTrivial = AllAddrModesTrivial && NewAddrMode.isTrivial();
2683
2684 // If this is the first addrmode then everything is fine.
2685 if (AddrModes.empty()) {
2686 AddrModes.emplace_back(NewAddrMode);
2687 return true;
2688 }
2689
2690 // Figure out how different this is from the other address modes, which we
2691 // can do just by comparing against the first one given that we only care
2692 // about the cumulative difference.
2693 ExtAddrMode::FieldName ThisDifferentField =
2694 AddrModes[0].compare(NewAddrMode);
2695 if (DifferentField == ExtAddrMode::NoField)
2696 DifferentField = ThisDifferentField;
2697 else if (DifferentField != ThisDifferentField)
2698 DifferentField = ExtAddrMode::MultipleFields;
2699
2700 // If NewAddrMode differs in more than one dimension we cannot handle it.
2701 bool CanHandle = DifferentField != ExtAddrMode::MultipleFields;
2702
2703 // If Scale Field is different then we reject.
2704 CanHandle = CanHandle && DifferentField != ExtAddrMode::ScaleField;
2705
2706 // We also must reject the case when base offset is different and
2707 // scale reg is not null, we cannot handle this case due to merge of
2708 // different offsets will be used as ScaleReg.
2709 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseOffsField ||
2710 !NewAddrMode.ScaledReg);
2711
2712 // We also must reject the case when GV is different and BaseReg installed
2713 // due to we want to use base reg as a merge of GV values.
2714 CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseGVField ||
2715 !NewAddrMode.HasBaseReg);
2716
2717 // Even if NewAddMode is the same we still need to collect it due to
2718 // original value is different. And later we will need all original values
2719 // as anchors during finding the common Phi node.
2720 if (CanHandle)
2721 AddrModes.emplace_back(NewAddrMode);
2722 else
2723 AddrModes.clear();
2724
2725 return CanHandle;
2726 }
2727
2728 /// \brief Combine the addressing modes we've collected into a single
2729 /// addressing mode.
2730 /// \return True iff we successfully combined them or we only had one so
2731 /// didn't need to combine them anyway.
2732 bool combineAddrModes() {
2733 // If we have no AddrModes then they can't be combined.
2734 if (AddrModes.size() == 0)
27
Assuming the condition is false
28
Taking false branch
2735 return false;
2736
2737 // A single AddrMode can trivially be combined.
2738 if (AddrModes.size() == 1 || DifferentField == ExtAddrMode::NoField)
29
Assuming the condition is false
30
Assuming the condition is false
31
Taking false branch
2739 return true;
2740
2741 // If the AddrModes we collected are all just equal to the value they are
2742 // derived from then combining them wouldn't do anything useful.
2743 if (AllAddrModesTrivial)
32
Assuming the condition is false
33
Taking false branch
2744 return false;
2745
2746 if (!addrModeCombiningAllowed())
34
Assuming the condition is false
35
Taking false branch
2747 return false;
2748
2749 // Build a map between <original value, basic block where we saw it> to
2750 // value of base register.
2751 // Bail out if there is no common type.
2752 FoldAddrToValueMapping Map;
2753 if (!initializeMap(Map))
36
Taking false branch
2754 return false;
2755
2756 Value *CommonValue = findCommon(Map);
37
Calling 'AddressingModeCombiner::findCommon'
2757 if (CommonValue)
2758 AddrModes[0].SetCombinedField(DifferentField, CommonValue, AddrModes);
2759 return CommonValue != nullptr;
2760 }
2761
2762private:
2763 /// \brief Initialize Map with anchor values. For address seen in some BB
2764 /// we set the value of different field saw in this address.
2765 /// If address is not an instruction than basic block is set to null.
2766 /// At the same time we find a common type for different field we will
2767 /// use to create new Phi/Select nodes. Keep it in CommonType field.
2768 /// Return false if there is no common type found.
2769 bool initializeMap(FoldAddrToValueMapping &Map) {
2770 // Keep track of keys where the value is null. We will need to replace it
2771 // with constant null when we know the common type.
2772 SmallVector<ValueInBB, 2> NullValue;
2773 Type *IntPtrTy = SQ.DL.getIntPtrType(AddrModes[0].OriginalValue->getType());
2774 for (auto &AM : AddrModes) {
2775 BasicBlock *BB = nullptr;
2776 if (Instruction *I = dyn_cast<Instruction>(AM.OriginalValue))
2777 BB = I->getParent();
2778
2779 Value *DV = AM.GetFieldAsValue(DifferentField, IntPtrTy);
2780 if (DV) {
2781 auto *Type = DV->getType();
2782 if (CommonType && CommonType != Type)
2783 return false;
2784 CommonType = Type;
2785 Map[{ AM.OriginalValue, BB }] = DV;
2786 } else {
2787 NullValue.push_back({ AM.OriginalValue, BB });
2788 }
2789 }
2790 assert(CommonType && "At least one non-null value must be!")(static_cast <bool> (CommonType && "At least one non-null value must be!"
) ? void (0) : __assert_fail ("CommonType && \"At least one non-null value must be!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 2790, __extension__ __PRETTY_FUNCTION__))
;
2791 for (auto VIBB : NullValue)
2792 Map[VIBB] = Constant::getNullValue(CommonType);
2793 return true;
2794 }
2795
2796 /// \brief We have mapping between value A and basic block where value A
2797 /// seen to other value B where B was a field in addressing mode represented
2798 /// by A. Also we have an original value C representin an address in some
2799 /// basic block. Traversing from C through phi and selects we ended up with
2800 /// A's in a map. This utility function tries to find a value V which is a
2801 /// field in addressing mode C and traversing through phi nodes and selects
2802 /// we will end up in corresponded values B in a map.
2803 /// The utility will create a new Phi/Selects if needed.
2804 // The simple example looks as follows:
2805 // BB1:
2806 // p1 = b1 + 40
2807 // br cond BB2, BB3
2808 // BB2:
2809 // p2 = b2 + 40
2810 // br BB3
2811 // BB3:
2812 // p = phi [p1, BB1], [p2, BB2]
2813 // v = load p
2814 // Map is
2815 // <p1, BB1> -> b1
2816 // <p2, BB2> -> b2
2817 // Request is
2818 // <p, BB3> -> ?
2819 // The function tries to find or build phi [b1, BB1], [b2, BB2] in BB3
2820 Value *findCommon(FoldAddrToValueMapping &Map) {
2821 // Tracks newly created Phi nodes.
2822 SmallPtrSet<PHINode *, 32> NewPhiNodes;
2823 // Tracks newly created Select nodes.
2824 SmallPtrSet<SelectInst *, 32> NewSelectNodes;
2825 // Tracks the simplification of newly created phi nodes. The reason we use
2826 // this mapping is because we will add new created Phi nodes in AddrToBase.
2827 // Simplification of Phi nodes is recursive, so some Phi node may
2828 // be simplified after we added it to AddrToBase.
2829 // Using this mapping we can find the current value in AddrToBase.
2830 SimplificationTracker ST(SQ, NewPhiNodes, NewSelectNodes);
2831
2832 // First step, DFS to create PHI nodes for all intermediate blocks.
2833 // Also fill traverse order for the second step.
2834 SmallVector<ValueInBB, 32> TraverseOrder;
2835 InsertPlaceholders(Map, TraverseOrder, NewPhiNodes, NewSelectNodes);
38
Calling 'AddressingModeCombiner::InsertPlaceholders'
2836
2837 // Second Step, fill new nodes by merged values and simplify if possible.
2838 FillPlaceholders(Map, TraverseOrder, ST);
2839
2840 if (!AddrSinkNewSelects && NewSelectNodes.size() > 0) {
2841 DestroyNodes(NewPhiNodes);
2842 DestroyNodes(NewSelectNodes);
2843 return nullptr;
2844 }
2845
2846 // Now we'd like to match New Phi nodes to existed ones.
2847 unsigned PhiNotMatchedCount = 0;
2848 if (!MatchPhiSet(NewPhiNodes, ST, AddrSinkNewPhis, PhiNotMatchedCount)) {
2849 DestroyNodes(NewPhiNodes);
2850 DestroyNodes(NewSelectNodes);
2851 return nullptr;
2852 }
2853
2854 auto *Result = ST.Get(Map.find(Original)->second);
2855 if (Result) {
2856 NumMemoryInstsPhiCreated += NewPhiNodes.size() + PhiNotMatchedCount;
2857 NumMemoryInstsSelectCreated += NewSelectNodes.size();
2858 }
2859 return Result;
2860 }
2861
2862 /// \brief Destroy nodes from a set.
2863 template <typename T> void DestroyNodes(SmallPtrSetImpl<T *> &Instructions) {
2864 // For safe erasing, replace the Phi with dummy value first.
2865 auto Dummy = UndefValue::get(CommonType);
2866 for (auto I : Instructions) {
2867 I->replaceAllUsesWith(Dummy);
2868 I->eraseFromParent();
2869 }
2870 }
2871
2872 /// \brief Try to match PHI node to Candidate.
2873 /// Matcher tracks the matched Phi nodes.
2874 bool MatchPhiNode(PHINode *PHI, PHINode *Candidate,
2875 DenseSet<PHIPair> &Matcher,
2876 SmallPtrSetImpl<PHINode *> &PhiNodesToMatch) {
2877 SmallVector<PHIPair, 8> WorkList;
2878 Matcher.insert({ PHI, Candidate });
2879 WorkList.push_back({ PHI, Candidate });
2880 SmallSet<PHIPair, 8> Visited;
2881 while (!WorkList.empty()) {
2882 auto Item = WorkList.pop_back_val();
2883 if (!Visited.insert(Item).second)
2884 continue;
2885 // We iterate over all incoming values to Phi to compare them.
2886 // If values are different and both of them Phi and the first one is a
2887 // Phi we added (subject to match) and both of them is in the same basic
2888 // block then we can match our pair if values match. So we state that
2889 // these values match and add it to work list to verify that.
2890 for (auto B : Item.first->blocks()) {
2891 Value *FirstValue = Item.first->getIncomingValueForBlock(B);
2892 Value *SecondValue = Item.second->getIncomingValueForBlock(B);
2893 if (FirstValue == SecondValue)
2894 continue;
2895
2896 PHINode *FirstPhi = dyn_cast<PHINode>(FirstValue);
2897 PHINode *SecondPhi = dyn_cast<PHINode>(SecondValue);
2898
2899 // One of them is not Phi or
2900 // The first one is not Phi node from the set we'd like to match or
2901 // Phi nodes from different basic blocks then
2902 // we will not be able to match.
2903 if (!FirstPhi || !SecondPhi || !PhiNodesToMatch.count(FirstPhi) ||
2904 FirstPhi->getParent() != SecondPhi->getParent())
2905 return false;
2906
2907 // If we already matched them then continue.
2908 if (Matcher.count({ FirstPhi, SecondPhi }))
2909 continue;
2910 // So the values are different and does not match. So we need them to
2911 // match.
2912 Matcher.insert({ FirstPhi, SecondPhi });
2913 // But me must check it.
2914 WorkList.push_back({ FirstPhi, SecondPhi });
2915 }
2916 }
2917 return true;
2918 }
2919
2920 /// \brief For the given set of PHI nodes try to find their equivalents.
2921 /// Returns false if this matching fails and creation of new Phi is disabled.
2922 bool MatchPhiSet(SmallPtrSetImpl<PHINode *> &PhiNodesToMatch,
2923 SimplificationTracker &ST, bool AllowNewPhiNodes,
2924 unsigned &PhiNotMatchedCount) {
2925 DenseSet<PHIPair> Matched;
2926 SmallPtrSet<PHINode *, 8> WillNotMatch;
2927 while (PhiNodesToMatch.size()) {
2928 PHINode *PHI = *PhiNodesToMatch.begin();
2929
2930 // Add us, if no Phi nodes in the basic block we do not match.
2931 WillNotMatch.clear();
2932 WillNotMatch.insert(PHI);
2933
2934 // Traverse all Phis until we found equivalent or fail to do that.
2935 bool IsMatched = false;
2936 for (auto &P : PHI->getParent()->phis()) {
2937 if (&P == PHI)
2938 continue;
2939 if ((IsMatched = MatchPhiNode(PHI, &P, Matched, PhiNodesToMatch)))
2940 break;
2941 // If it does not match, collect all Phi nodes from matcher.
2942 // if we end up with no match, them all these Phi nodes will not match
2943 // later.
2944 for (auto M : Matched)
2945 WillNotMatch.insert(M.first);
2946 Matched.clear();
2947 }
2948 if (IsMatched) {
2949 // Replace all matched values and erase them.
2950 for (auto MV : Matched) {
2951 MV.first->replaceAllUsesWith(MV.second);
2952 PhiNodesToMatch.erase(MV.first);
2953 ST.Put(MV.first, MV.second);
2954 MV.first->eraseFromParent();
2955 }
2956 Matched.clear();
2957 continue;
2958 }
2959 // If we are not allowed to create new nodes then bail out.
2960 if (!AllowNewPhiNodes)
2961 return false;
2962 // Just remove all seen values in matcher. They will not match anything.
2963 PhiNotMatchedCount += WillNotMatch.size();
2964 for (auto *P : WillNotMatch)
2965 PhiNodesToMatch.erase(P);
2966 }
2967 return true;
2968 }
2969 /// \brief Fill the placeholder with values from predecessors and simplify it.
2970 void FillPlaceholders(FoldAddrToValueMapping &Map,
2971 SmallVectorImpl<ValueInBB> &TraverseOrder,
2972 SimplificationTracker &ST) {
2973 while (!TraverseOrder.empty()) {
2974 auto Current = TraverseOrder.pop_back_val();
2975 assert(Map.find(Current) != Map.end() && "No node to fill!!!")(static_cast <bool> (Map.find(Current) != Map.end() &&
"No node to fill!!!") ? void (0) : __assert_fail ("Map.find(Current) != Map.end() && \"No node to fill!!!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 2975, __extension__ __PRETTY_FUNCTION__))
;
2976 Value *CurrentValue = Current.first;
2977 BasicBlock *CurrentBlock = Current.second;
2978 Value *V = Map[Current];
2979
2980 if (SelectInst *Select = dyn_cast<SelectInst>(V)) {
2981 // CurrentValue also must be Select.
2982 auto *CurrentSelect = cast<SelectInst>(CurrentValue);
2983 auto *TrueValue = CurrentSelect->getTrueValue();
2984 ValueInBB TrueItem = { TrueValue, isa<Instruction>(TrueValue)
2985 ? CurrentBlock
2986 : nullptr };
2987 assert(Map.find(TrueItem) != Map.end() && "No True Value!")(static_cast <bool> (Map.find(TrueItem) != Map.end() &&
"No True Value!") ? void (0) : __assert_fail ("Map.find(TrueItem) != Map.end() && \"No True Value!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 2987, __extension__ __PRETTY_FUNCTION__))
;
2988 Select->setTrueValue(ST.Get(Map[TrueItem]));
2989 auto *FalseValue = CurrentSelect->getFalseValue();
2990 ValueInBB FalseItem = { FalseValue, isa<Instruction>(FalseValue)
2991 ? CurrentBlock
2992 : nullptr };
2993 assert(Map.find(FalseItem) != Map.end() && "No False Value!")(static_cast <bool> (Map.find(FalseItem) != Map.end() &&
"No False Value!") ? void (0) : __assert_fail ("Map.find(FalseItem) != Map.end() && \"No False Value!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 2993, __extension__ __PRETTY_FUNCTION__))
;
2994 Select->setFalseValue(ST.Get(Map[FalseItem]));
2995 } else {
2996 // Must be a Phi node then.
2997 PHINode *PHI = cast<PHINode>(V);
2998 // Fill the Phi node with values from predecessors.
2999 bool IsDefinedInThisBB =
3000 cast<Instruction>(CurrentValue)->getParent() == CurrentBlock;
3001 auto *CurrentPhi = dyn_cast<PHINode>(CurrentValue);
3002 for (auto B : predecessors(CurrentBlock)) {
3003 Value *PV = IsDefinedInThisBB
3004 ? CurrentPhi->getIncomingValueForBlock(B)
3005 : CurrentValue;
3006 ValueInBB item = { PV, isa<Instruction>(PV) ? B : nullptr };
3007 assert(Map.find(item) != Map.end() && "No predecessor Value!")(static_cast <bool> (Map.find(item) != Map.end() &&
"No predecessor Value!") ? void (0) : __assert_fail ("Map.find(item) != Map.end() && \"No predecessor Value!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3007, __extension__ __PRETTY_FUNCTION__))
;
3008 PHI->addIncoming(ST.Get(Map[item]), B);
3009 }
3010 }
3011 // Simplify if possible.
3012 Map[Current] = ST.Simplify(V);
3013 }
3014 }
3015
3016 /// Starting from value recursively iterates over predecessors up to known
3017 /// ending values represented in a map. For each traversed block inserts
3018 /// a placeholder Phi or Select.
3019 /// Reports all new created Phi/Select nodes by adding them to set.
3020 /// Also reports and order in what basic blocks have been traversed.
3021 void InsertPlaceholders(FoldAddrToValueMapping &Map,
3022 SmallVectorImpl<ValueInBB> &TraverseOrder,
3023 SmallPtrSetImpl<PHINode *> &NewPhiNodes,
3024 SmallPtrSetImpl<SelectInst *> &NewSelectNodes) {
3025 SmallVector<ValueInBB, 32> Worklist;
3026 assert((isa<PHINode>(Original.first) || isa<SelectInst>(Original.first)) &&(static_cast <bool> ((isa<PHINode>(Original.first
) || isa<SelectInst>(Original.first)) && "Address must be a Phi or Select node"
) ? void (0) : __assert_fail ("(isa<PHINode>(Original.first) || isa<SelectInst>(Original.first)) && \"Address must be a Phi or Select node\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3027, __extension__ __PRETTY_FUNCTION__))
3027 "Address must be a Phi or Select node")(static_cast <bool> ((isa<PHINode>(Original.first
) || isa<SelectInst>(Original.first)) && "Address must be a Phi or Select node"
) ? void (0) : __assert_fail ("(isa<PHINode>(Original.first) || isa<SelectInst>(Original.first)) && \"Address must be a Phi or Select node\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3027, __extension__ __PRETTY_FUNCTION__))
;
3028 auto *Dummy = UndefValue::get(CommonType);
3029 Worklist.push_back(Original);
3030 while (!Worklist.empty()) {
39
Loop condition is true. Entering loop body
3031 auto Current = Worklist.pop_back_val();
3032 // If value is not an instruction it is something global, constant,
3033 // parameter and we can say that this value is observable in any block.
3034 // Set block to null to denote it.
3035 // Also please take into account that it is how we build anchors.
3036 if (!isa<Instruction>(Current.first))
40
Taking true branch
3037 Current.second = nullptr;
41
Null pointer value stored to 'Current.second'
3038 // if it is already visited or it is an ending value then skip it.
3039 if (Map.find(Current) != Map.end())
42
Assuming the condition is false
43
Taking false branch
3040 continue;
3041 TraverseOrder.push_back(Current);
3042
3043 Value *CurrentValue = Current.first;
3044 BasicBlock *CurrentBlock = Current.second;
44
'CurrentBlock' initialized to a null pointer value
3045 // CurrentValue must be a Phi node or select. All others must be covered
3046 // by anchors.
3047 Instruction *CurrentI = cast<Instruction>(CurrentValue);
3048 bool IsDefinedInThisBB = CurrentI->getParent() == CurrentBlock;
45
Assuming the condition is true
3049
3050 unsigned PredCount =
3051 std::distance(pred_begin(CurrentBlock), pred_end(CurrentBlock));
3052 // if Current Value is not defined in this basic block we are interested
3053 // in values in predecessors.
3054 if (!IsDefinedInThisBB) {
46
Taking false branch
3055 assert(PredCount && "Unreachable block?!")(static_cast <bool> (PredCount && "Unreachable block?!"
) ? void (0) : __assert_fail ("PredCount && \"Unreachable block?!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3055, __extension__ __PRETTY_FUNCTION__))
;
3056 PHINode *PHI = PHINode::Create(CommonType, PredCount, "sunk_phi",
3057 &CurrentBlock->front());
3058 Map[Current] = PHI;
3059 NewPhiNodes.insert(PHI);
3060 // Add all predecessors in work list.
3061 for (auto B : predecessors(CurrentBlock))
3062 Worklist.push_back({ CurrentValue, B });
3063 continue;
3064 }
3065 // Value is defined in this basic block.
3066 if (SelectInst *OrigSelect = dyn_cast<SelectInst>(CurrentI)) {
47
Taking false branch
3067 // Is it OK to get metadata from OrigSelect?!
3068 // Create a Select placeholder with dummy value.
3069 SelectInst *Select =
3070 SelectInst::Create(OrigSelect->getCondition(), Dummy, Dummy,
3071 OrigSelect->getName(), OrigSelect, OrigSelect);
3072 Map[Current] = Select;
3073 NewSelectNodes.insert(Select);
3074 // We are interested in True and False value in this basic block.
3075 Worklist.push_back({ OrigSelect->getTrueValue(), CurrentBlock });
3076 Worklist.push_back({ OrigSelect->getFalseValue(), CurrentBlock });
3077 } else {
3078 // It must be a Phi node then.
3079 auto *CurrentPhi = cast<PHINode>(CurrentI);
3080 // Create new Phi node for merge of bases.
3081 assert(PredCount && "Unreachable block?!")(static_cast <bool> (PredCount && "Unreachable block?!"
) ? void (0) : __assert_fail ("PredCount && \"Unreachable block?!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3081, __extension__ __PRETTY_FUNCTION__))
;
3082 PHINode *PHI = PHINode::Create(CommonType, PredCount, "sunk_phi",
3083 &CurrentBlock->front());
48
Called C++ object pointer is null
3084 Map[Current] = PHI;
3085 NewPhiNodes.insert(PHI);
3086
3087 // Add all predecessors in work list.
3088 for (auto B : predecessors(CurrentBlock))
3089 Worklist.push_back({ CurrentPhi->getIncomingValueForBlock(B), B });
3090 }
3091 }
3092 }
3093
3094 bool addrModeCombiningAllowed() {
3095 if (DisableComplexAddrModes)
3096 return false;
3097 switch (DifferentField) {
3098 default:
3099 return false;
3100 case ExtAddrMode::BaseRegField:
3101 return AddrSinkCombineBaseReg;
3102 case ExtAddrMode::BaseGVField:
3103 return AddrSinkCombineBaseGV;
3104 case ExtAddrMode::BaseOffsField:
3105 return AddrSinkCombineBaseOffs;
3106 case ExtAddrMode::ScaledRegField:
3107 return AddrSinkCombineScaledReg;
3108 }
3109 }
3110};
3111} // end anonymous namespace
3112
3113/// Try adding ScaleReg*Scale to the current addressing mode.
3114/// Return true and update AddrMode if this addr mode is legal for the target,
3115/// false if not.
3116bool AddressingModeMatcher::matchScaledValue(Value *ScaleReg, int64_t Scale,
3117 unsigned Depth) {
3118 // If Scale is 1, then this is the same as adding ScaleReg to the addressing
3119 // mode. Just process that directly.
3120 if (Scale == 1)
3121 return matchAddr(ScaleReg, Depth);
3122
3123 // If the scale is 0, it takes nothing to add this.
3124 if (Scale == 0)
3125 return true;
3126
3127 // If we already have a scale of this value, we can add to it, otherwise, we
3128 // need an available scale field.
3129 if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
3130 return false;
3131
3132 ExtAddrMode TestAddrMode = AddrMode;
3133
3134 // Add scale to turn X*4+X*3 -> X*7. This could also do things like
3135 // [A+B + A*7] -> [B+A*8].
3136 TestAddrMode.Scale += Scale;
3137 TestAddrMode.ScaledReg = ScaleReg;
3138
3139 // If the new address isn't legal, bail out.
3140 if (!TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace))
3141 return false;
3142
3143 // It was legal, so commit it.
3144 AddrMode = TestAddrMode;
3145
3146 // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
3147 // to see if ScaleReg is actually X+C. If so, we can turn this into adding
3148 // X*Scale + C*Scale to addr mode.
3149 ConstantInt *CI = nullptr; Value *AddLHS = nullptr;
3150 if (isa<Instruction>(ScaleReg) && // not a constant expr.
3151 match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI)))) {
3152 TestAddrMode.ScaledReg = AddLHS;
3153 TestAddrMode.BaseOffs += CI->getSExtValue()*TestAddrMode.Scale;
3154
3155 // If this addressing mode is legal, commit it and remember that we folded
3156 // this instruction.
3157 if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace)) {
3158 AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
3159 AddrMode = TestAddrMode;
3160 return true;
3161 }
3162 }
3163
3164 // Otherwise, not (x+c)*scale, just return what we have.
3165 return true;
3166}
3167
3168/// This is a little filter, which returns true if an addressing computation
3169/// involving I might be folded into a load/store accessing it.
3170/// This doesn't need to be perfect, but needs to accept at least
3171/// the set of instructions that MatchOperationAddr can.
3172static bool MightBeFoldableInst(Instruction *I) {
3173 switch (I->getOpcode()) {
3174 case Instruction::BitCast:
3175 case Instruction::AddrSpaceCast:
3176 // Don't touch identity bitcasts.
3177 if (I->getType() == I->getOperand(0)->getType())
3178 return false;
3179 return I->getType()->isPointerTy() || I->getType()->isIntegerTy();
3180 case Instruction::PtrToInt:
3181 // PtrToInt is always a noop, as we know that the int type is pointer sized.
3182 return true;
3183 case Instruction::IntToPtr:
3184 // We know the input is intptr_t, so this is foldable.
3185 return true;
3186 case Instruction::Add:
3187 return true;
3188 case Instruction::Mul:
3189 case Instruction::Shl:
3190 // Can only handle X*C and X << C.
3191 return isa<ConstantInt>(I->getOperand(1));
3192 case Instruction::GetElementPtr:
3193 return true;
3194 default:
3195 return false;
3196 }
3197}
3198
3199/// \brief Check whether or not \p Val is a legal instruction for \p TLI.
3200/// \note \p Val is assumed to be the product of some type promotion.
3201/// Therefore if \p Val has an undefined state in \p TLI, this is assumed
3202/// to be legal, as the non-promoted value would have had the same state.
3203static bool isPromotedInstructionLegal(const TargetLowering &TLI,
3204 const DataLayout &DL, Value *Val) {
3205 Instruction *PromotedInst = dyn_cast<Instruction>(Val);
3206 if (!PromotedInst)
3207 return false;
3208 int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
3209 // If the ISDOpcode is undefined, it was undefined before the promotion.
3210 if (!ISDOpcode)
3211 return true;
3212 // Otherwise, check if the promoted instruction is legal or not.
3213 return TLI.isOperationLegalOrCustom(
3214 ISDOpcode, TLI.getValueType(DL, PromotedInst->getType()));
3215}
3216
3217namespace {
3218
3219/// \brief Hepler class to perform type promotion.
3220class TypePromotionHelper {
3221 /// \brief Utility function to check whether or not a sign or zero extension
3222 /// of \p Inst with \p ConsideredExtType can be moved through \p Inst by
3223 /// either using the operands of \p Inst or promoting \p Inst.
3224 /// The type of the extension is defined by \p IsSExt.
3225 /// In other words, check if:
3226 /// ext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredExtType.
3227 /// #1 Promotion applies:
3228 /// ConsideredExtType Inst (ext opnd1 to ConsideredExtType, ...).
3229 /// #2 Operand reuses:
3230 /// ext opnd1 to ConsideredExtType.
3231 /// \p PromotedInsts maps the instructions to their type before promotion.
3232 static bool canGetThrough(const Instruction *Inst, Type *ConsideredExtType,
3233 const InstrToOrigTy &PromotedInsts, bool IsSExt);
3234
3235 /// \brief Utility function to determine if \p OpIdx should be promoted when
3236 /// promoting \p Inst.
3237 static bool shouldExtOperand(const Instruction *Inst, int OpIdx) {
3238 return !(isa<SelectInst>(Inst) && OpIdx == 0);
3239 }
3240
3241 /// \brief Utility function to promote the operand of \p Ext when this
3242 /// operand is a promotable trunc or sext or zext.
3243 /// \p PromotedInsts maps the instructions to their type before promotion.
3244 /// \p CreatedInstsCost[out] contains the cost of all instructions
3245 /// created to promote the operand of Ext.
3246 /// Newly added extensions are inserted in \p Exts.
3247 /// Newly added truncates are inserted in \p Truncs.
3248 /// Should never be called directly.
3249 /// \return The promoted value which is used instead of Ext.
3250 static Value *promoteOperandForTruncAndAnyExt(
3251 Instruction *Ext, TypePromotionTransaction &TPT,
3252 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3253 SmallVectorImpl<Instruction *> *Exts,
3254 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI);
3255
3256 /// \brief Utility function to promote the operand of \p Ext when this
3257 /// operand is promotable and is not a supported trunc or sext.
3258 /// \p PromotedInsts maps the instructions to their type before promotion.
3259 /// \p CreatedInstsCost[out] contains the cost of all the instructions
3260 /// created to promote the operand of Ext.
3261 /// Newly added extensions are inserted in \p Exts.
3262 /// Newly added truncates are inserted in \p Truncs.
3263 /// Should never be called directly.
3264 /// \return The promoted value which is used instead of Ext.
3265 static Value *promoteOperandForOther(Instruction *Ext,
3266 TypePromotionTransaction &TPT,
3267 InstrToOrigTy &PromotedInsts,
3268 unsigned &CreatedInstsCost,
3269 SmallVectorImpl<Instruction *> *Exts,
3270 SmallVectorImpl<Instruction *> *Truncs,
3271 const TargetLowering &TLI, bool IsSExt);
3272
3273 /// \see promoteOperandForOther.
3274 static Value *signExtendOperandForOther(
3275 Instruction *Ext, TypePromotionTransaction &TPT,
3276 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3277 SmallVectorImpl<Instruction *> *Exts,
3278 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3279 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
3280 Exts, Truncs, TLI, true);
3281 }
3282
3283 /// \see promoteOperandForOther.
3284 static Value *zeroExtendOperandForOther(
3285 Instruction *Ext, TypePromotionTransaction &TPT,
3286 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3287 SmallVectorImpl<Instruction *> *Exts,
3288 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3289 return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
3290 Exts, Truncs, TLI, false);
3291 }
3292
3293public:
3294 /// Type for the utility function that promotes the operand of Ext.
3295 using Action = Value *(*)(Instruction *Ext, TypePromotionTransaction &TPT,
3296 InstrToOrigTy &PromotedInsts,
3297 unsigned &CreatedInstsCost,
3298 SmallVectorImpl<Instruction *> *Exts,
3299 SmallVectorImpl<Instruction *> *Truncs,
3300 const TargetLowering &TLI);
3301
3302 /// \brief Given a sign/zero extend instruction \p Ext, return the approriate
3303 /// action to promote the operand of \p Ext instead of using Ext.
3304 /// \return NULL if no promotable action is possible with the current
3305 /// sign extension.
3306 /// \p InsertedInsts keeps track of all the instructions inserted by the
3307 /// other CodeGenPrepare optimizations. This information is important
3308 /// because we do not want to promote these instructions as CodeGenPrepare
3309 /// will reinsert them later. Thus creating an infinite loop: create/remove.
3310 /// \p PromotedInsts maps the instructions to their type before promotion.
3311 static Action getAction(Instruction *Ext, const SetOfInstrs &InsertedInsts,
3312 const TargetLowering &TLI,
3313 const InstrToOrigTy &PromotedInsts);
3314};
3315
3316} // end anonymous namespace
3317
3318bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
3319 Type *ConsideredExtType,
3320 const InstrToOrigTy &PromotedInsts,
3321 bool IsSExt) {
3322 // The promotion helper does not know how to deal with vector types yet.
3323 // To be able to fix that, we would need to fix the places where we
3324 // statically extend, e.g., constants and such.
3325 if (Inst->getType()->isVectorTy())
3326 return false;
3327
3328 // We can always get through zext.
3329 if (isa<ZExtInst>(Inst))
3330 return true;
3331
3332 // sext(sext) is ok too.
3333 if (IsSExt && isa<SExtInst>(Inst))
3334 return true;
3335
3336 // We can get through binary operator, if it is legal. In other words, the
3337 // binary operator must have a nuw or nsw flag.
3338 const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst);
3339 if (BinOp && isa<OverflowingBinaryOperator>(BinOp) &&
3340 ((!IsSExt && BinOp->hasNoUnsignedWrap()) ||
3341 (IsSExt && BinOp->hasNoSignedWrap())))
3342 return true;
3343
3344 // Check if we can do the following simplification.
3345 // ext(trunc(opnd)) --> ext(opnd)
3346 if (!isa<TruncInst>(Inst))
3347 return false;
3348
3349 Value *OpndVal = Inst->getOperand(0);
3350 // Check if we can use this operand in the extension.
3351 // If the type is larger than the result type of the extension, we cannot.
3352 if (!OpndVal->getType()->isIntegerTy() ||
3353 OpndVal->getType()->getIntegerBitWidth() >
3354 ConsideredExtType->getIntegerBitWidth())
3355 return false;
3356
3357 // If the operand of the truncate is not an instruction, we will not have
3358 // any information on the dropped bits.
3359 // (Actually we could for constant but it is not worth the extra logic).
3360 Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
3361 if (!Opnd)
3362 return false;
3363
3364 // Check if the source of the type is narrow enough.
3365 // I.e., check that trunc just drops extended bits of the same kind of
3366 // the extension.
3367 // #1 get the type of the operand and check the kind of the extended bits.
3368 const Type *OpndType;
3369 InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
3370 if (It != PromotedInsts.end() && It->second.getInt() == IsSExt)
3371 OpndType = It->second.getPointer();
3372 else if ((IsSExt && isa<SExtInst>(Opnd)) || (!IsSExt && isa<ZExtInst>(Opnd)))
3373 OpndType = Opnd->getOperand(0)->getType();
3374 else
3375 return false;
3376
3377 // #2 check that the truncate just drops extended bits.
3378 return Inst->getType()->getIntegerBitWidth() >=
3379 OpndType->getIntegerBitWidth();
3380}
3381
3382TypePromotionHelper::Action TypePromotionHelper::getAction(
3383 Instruction *Ext, const SetOfInstrs &InsertedInsts,
3384 const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
3385 assert((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&(static_cast <bool> ((isa<SExtInst>(Ext) || isa<
ZExtInst>(Ext)) && "Unexpected instruction type") ?
void (0) : __assert_fail ("(isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) && \"Unexpected instruction type\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3386, __extension__ __PRETTY_FUNCTION__))
3386 "Unexpected instruction type")(static_cast <bool> ((isa<SExtInst>(Ext) || isa<
ZExtInst>(Ext)) && "Unexpected instruction type") ?
void (0) : __assert_fail ("(isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) && \"Unexpected instruction type\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3386, __extension__ __PRETTY_FUNCTION__))
;
3387 Instruction *ExtOpnd = dyn_cast<Instruction>(Ext->getOperand(0));
3388 Type *ExtTy = Ext->getType();
3389 bool IsSExt = isa<SExtInst>(Ext);
3390 // If the operand of the extension is not an instruction, we cannot
3391 // get through.
3392 // If it, check we can get through.
3393 if (!ExtOpnd || !canGetThrough(ExtOpnd, ExtTy, PromotedInsts, IsSExt))
3394 return nullptr;
3395
3396 // Do not promote if the operand has been added by codegenprepare.
3397 // Otherwise, it means we are undoing an optimization that is likely to be
3398 // redone, thus causing potential infinite loop.
3399 if (isa<TruncInst>(ExtOpnd) && InsertedInsts.count(ExtOpnd))
3400 return nullptr;
3401
3402 // SExt or Trunc instructions.
3403 // Return the related handler.
3404 if (isa<SExtInst>(ExtOpnd) || isa<TruncInst>(ExtOpnd) ||
3405 isa<ZExtInst>(ExtOpnd))
3406 return promoteOperandForTruncAndAnyExt;
3407
3408 // Regular instruction.
3409 // Abort early if we will have to insert non-free instructions.
3410 if (!ExtOpnd->hasOneUse() && !TLI.isTruncateFree(ExtTy, ExtOpnd->getType()))
3411 return nullptr;
3412 return IsSExt ? signExtendOperandForOther : zeroExtendOperandForOther;
3413}
3414
3415Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
3416 Instruction *SExt, TypePromotionTransaction &TPT,
3417 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3418 SmallVectorImpl<Instruction *> *Exts,
3419 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
3420 // By construction, the operand of SExt is an instruction. Otherwise we cannot
3421 // get through it and this method should not be called.
3422 Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
3423 Value *ExtVal = SExt;
3424 bool HasMergedNonFreeExt = false;
3425 if (isa<ZExtInst>(SExtOpnd)) {
3426 // Replace s|zext(zext(opnd))
3427 // => zext(opnd).
3428 HasMergedNonFreeExt = !TLI.isExtFree(SExtOpnd);
3429 Value *ZExt =
3430 TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
3431 TPT.replaceAllUsesWith(SExt, ZExt);
3432 TPT.eraseInstruction(SExt);
3433 ExtVal = ZExt;
3434 } else {
3435 // Replace z|sext(trunc(opnd)) or sext(sext(opnd))
3436 // => z|sext(opnd).
3437 TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
3438 }
3439 CreatedInstsCost = 0;
3440
3441 // Remove dead code.
3442 if (SExtOpnd->use_empty())
3443 TPT.eraseInstruction(SExtOpnd);
3444
3445 // Check if the extension is still needed.
3446 Instruction *ExtInst = dyn_cast<Instruction>(ExtVal);
3447 if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) {
3448 if (ExtInst) {
3449 if (Exts)
3450 Exts->push_back(ExtInst);
3451 CreatedInstsCost = !TLI.isExtFree(ExtInst) && !HasMergedNonFreeExt;
3452 }
3453 return ExtVal;
3454 }
3455
3456 // At this point we have: ext ty opnd to ty.
3457 // Reassign the uses of ExtInst to the opnd and remove ExtInst.
3458 Value *NextVal = ExtInst->getOperand(0);
3459 TPT.eraseInstruction(ExtInst, NextVal);
3460 return NextVal;
3461}
3462
3463Value *TypePromotionHelper::promoteOperandForOther(
3464 Instruction *Ext, TypePromotionTransaction &TPT,
3465 InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
3466 SmallVectorImpl<Instruction *> *Exts,
3467 SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI,
3468 bool IsSExt) {
3469 // By construction, the operand of Ext is an instruction. Otherwise we cannot
3470 // get through it and this method should not be called.
3471 Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0));
3472 CreatedInstsCost = 0;
3473 if (!ExtOpnd->hasOneUse()) {
3474 // ExtOpnd will be promoted.
3475 // All its uses, but Ext, will need to use a truncated value of the
3476 // promoted version.
3477 // Create the truncate now.
3478 Value *Trunc = TPT.createTrunc(Ext, ExtOpnd->getType());
3479 if (Instruction *ITrunc = dyn_cast<Instruction>(Trunc)) {
3480 // Insert it just after the definition.
3481 ITrunc->moveAfter(ExtOpnd);
3482 if (Truncs)
3483 Truncs->push_back(ITrunc);
3484 }
3485
3486 TPT.replaceAllUsesWith(ExtOpnd, Trunc);
3487 // Restore the operand of Ext (which has been replaced by the previous call
3488 // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
3489 TPT.setOperand(Ext, 0, ExtOpnd);
3490 }
3491
3492 // Get through the Instruction:
3493 // 1. Update its type.
3494 // 2. Replace the uses of Ext by Inst.
3495 // 3. Extend each operand that needs to be extended.
3496
3497 // Remember the original type of the instruction before promotion.
3498 // This is useful to know that the high bits are sign extended bits.
3499 PromotedInsts.insert(std::pair<Instruction *, TypeIsSExt>(
3500 ExtOpnd, TypeIsSExt(ExtOpnd->getType(), IsSExt)));
3501 // Step #1.
3502 TPT.mutateType(ExtOpnd, Ext->getType());
3503 // Step #2.
3504 TPT.replaceAllUsesWith(Ext, ExtOpnd);
3505 // Step #3.
3506 Instruction *ExtForOpnd = Ext;
3507
3508 DEBUG(dbgs() << "Propagate Ext to operands\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Propagate Ext to operands\n"
; } } while (false)
;
3509 for (int OpIdx = 0, EndOpIdx = ExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
3510 ++OpIdx) {
3511 DEBUG(dbgs() << "Operand:\n" << *(ExtOpnd->getOperand(OpIdx)) << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Operand:\n" << *
(ExtOpnd->getOperand(OpIdx)) << '\n'; } } while (false
)
;
3512 if (ExtOpnd->getOperand(OpIdx)->getType() == Ext->getType() ||
3513 !shouldExtOperand(ExtOpnd, OpIdx)) {
3514 DEBUG(dbgs() << "No need to propagate\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "No need to propagate\n"
; } } while (false)
;
3515 continue;
3516 }
3517 // Check if we can statically extend the operand.
3518 Value *Opnd = ExtOpnd->getOperand(OpIdx);
3519 if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
3520 DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
} while (false)
;
3521 unsigned BitWidth = Ext->getType()->getIntegerBitWidth();
3522 APInt CstVal = IsSExt ? Cst->getValue().sext(BitWidth)
3523 : Cst->getValue().zext(BitWidth);
3524 TPT.setOperand(ExtOpnd, OpIdx, ConstantInt::get(Ext->getType(), CstVal));
3525 continue;
3526 }
3527 // UndefValue are typed, so we have to statically sign extend them.
3528 if (isa<UndefValue>(Opnd)) {
3529 DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
} while (false)
;
3530 TPT.setOperand(ExtOpnd, OpIdx, UndefValue::get(Ext->getType()));
3531 continue;
3532 }
3533
3534 // Otherwise we have to explicity sign extend the operand.
3535 // Check if Ext was reused to extend an operand.
3536 if (!ExtForOpnd) {
3537 // If yes, create a new one.
3538 DEBUG(dbgs() << "More operands to ext\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "More operands to ext\n"
; } } while (false)
;
3539 Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
3540 : TPT.createZExt(Ext, Opnd, Ext->getType());
3541 if (!isa<Instruction>(ValForExtOpnd)) {
3542 TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd);
3543 continue;
3544 }
3545 ExtForOpnd = cast<Instruction>(ValForExtOpnd);
3546 }
3547 if (Exts)
3548 Exts->push_back(ExtForOpnd);
3549 TPT.setOperand(ExtForOpnd, 0, Opnd);
3550
3551 // Move the sign extension before the insertion point.
3552 TPT.moveBefore(ExtForOpnd, ExtOpnd);
3553 TPT.setOperand(ExtOpnd, OpIdx, ExtForOpnd);
3554 CreatedInstsCost += !TLI.isExtFree(ExtForOpnd);
3555 // If more sext are required, new instructions will have to be created.
3556 ExtForOpnd = nullptr;
3557 }
3558 if (ExtForOpnd == Ext) {
3559 DEBUG(dbgs() << "Extension is useless now\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Extension is useless now\n"
; } } while (false)
;
3560 TPT.eraseInstruction(Ext);
3561 }
3562 return ExtOpnd;
3563}
3564
3565/// Check whether or not promoting an instruction to a wider type is profitable.
3566/// \p NewCost gives the cost of extension instructions created by the
3567/// promotion.
3568/// \p OldCost gives the cost of extension instructions before the promotion
3569/// plus the number of instructions that have been
3570/// matched in the addressing mode the promotion.
3571/// \p PromotedOperand is the value that has been promoted.
3572/// \return True if the promotion is profitable, false otherwise.
3573bool AddressingModeMatcher::isPromotionProfitable(
3574 unsigned NewCost, unsigned OldCost, Value *PromotedOperand) const {
3575 DEBUG(dbgs() << "OldCost: " << OldCost << "\tNewCost: " << NewCost << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "OldCost: " << OldCost
<< "\tNewCost: " << NewCost << '\n'; } } while
(false)
;
3576 // The cost of the new extensions is greater than the cost of the
3577 // old extension plus what we folded.
3578 // This is not profitable.
3579 if (NewCost > OldCost)
3580 return false;
3581 if (NewCost < OldCost)
3582 return true;
3583 // The promotion is neutral but it may help folding the sign extension in
3584 // loads for instance.
3585 // Check that we did not create an illegal instruction.
3586 return isPromotedInstructionLegal(TLI, DL, PromotedOperand);
3587}
3588
3589/// Given an instruction or constant expr, see if we can fold the operation
3590/// into the addressing mode. If so, update the addressing mode and return
3591/// true, otherwise return false without modifying AddrMode.
3592/// If \p MovedAway is not NULL, it contains the information of whether or
3593/// not AddrInst has to be folded into the addressing mode on success.
3594/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
3595/// because it has been moved away.
3596/// Thus AddrInst must not be added in the matched instructions.
3597/// This state can happen when AddrInst is a sext, since it may be moved away.
3598/// Therefore, AddrInst may not be valid when MovedAway is true and it must
3599/// not be referenced anymore.
3600bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
3601 unsigned Depth,
3602 bool *MovedAway) {
3603 // Avoid exponential behavior on extremely deep expression trees.
3604 if (Depth >= 5) return false;
3605
3606 // By default, all matched instructions stay in place.
3607 if (MovedAway)
3608 *MovedAway = false;
3609
3610 switch (Opcode) {
3611 case Instruction::PtrToInt:
3612 // PtrToInt is always a noop, as we know that the int type is pointer sized.
3613 return matchAddr(AddrInst->getOperand(0), Depth);
3614 case Instruction::IntToPtr: {
3615 auto AS = AddrInst->getType()->getPointerAddressSpace();
3616 auto PtrTy = MVT::getIntegerVT(DL.getPointerSizeInBits(AS));
3617 // This inttoptr is a no-op if the integer type is pointer sized.
3618 if (TLI.getValueType(DL, AddrInst->getOperand(0)->getType()) == PtrTy)
3619 return matchAddr(AddrInst->getOperand(0), Depth);
3620 return false;
3621 }
3622 case Instruction::BitCast:
3623 // BitCast is always a noop, and we can handle it as long as it is
3624 // int->int or pointer->pointer (we don't want int<->fp or something).
3625 if ((AddrInst->getOperand(0)->getType()->isPointerTy() ||
3626 AddrInst->getOperand(0)->getType()->isIntegerTy()) &&
3627 // Don't touch identity bitcasts. These were probably put here by LSR,
3628 // and we don't want to mess around with them. Assume it knows what it
3629 // is doing.
3630 AddrInst->getOperand(0)->getType() != AddrInst->getType())
3631 return matchAddr(AddrInst->getOperand(0), Depth);
3632 return false;
3633 case Instruction::AddrSpaceCast: {
3634 unsigned SrcAS
3635 = AddrInst->getOperand(0)->getType()->getPointerAddressSpace();
3636 unsigned DestAS = AddrInst->getType()->getPointerAddressSpace();
3637 if (TLI.isNoopAddrSpaceCast(SrcAS, DestAS))
3638 return matchAddr(AddrInst->getOperand(0), Depth);
3639 return false;
3640 }
3641 case Instruction::Add: {
3642 // Check to see if we can merge in the RHS then the LHS. If so, we win.
3643 ExtAddrMode BackupAddrMode = AddrMode;
3644 unsigned OldSize = AddrModeInsts.size();
3645 // Start a transaction at this point.
3646 // The LHS may match but not the RHS.
3647 // Therefore, we need a higher level restoration point to undo partially
3648 // matched operation.
3649 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
3650 TPT.getRestorationPoint();
3651
3652 if (matchAddr(AddrInst->getOperand(1), Depth+1) &&
3653 matchAddr(AddrInst->getOperand(0), Depth+1))
3654 return true;
3655
3656 // Restore the old addr mode info.
3657 AddrMode = BackupAddrMode;
3658 AddrModeInsts.resize(OldSize);
3659 TPT.rollback(LastKnownGood);
3660
3661 // Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
3662 if (matchAddr(AddrInst->getOperand(0), Depth+1) &&
3663 matchAddr(AddrInst->getOperand(1), Depth+1))
3664 return true;
3665
3666 // Otherwise we definitely can't merge the ADD in.
3667 AddrMode = BackupAddrMode;
3668 AddrModeInsts.resize(OldSize);
3669 TPT.rollback(LastKnownGood);
3670 break;
3671 }
3672 //case Instruction::Or:
3673 // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
3674 //break;
3675 case Instruction::Mul:
3676 case Instruction::Shl: {
3677 // Can only handle X*C and X << C.
3678 ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
3679 if (!RHS || RHS->getBitWidth() > 64)
3680 return false;
3681 int64_t Scale = RHS->getSExtValue();
3682 if (Opcode == Instruction::Shl)
3683 Scale = 1LL << Scale;
3684
3685 return matchScaledValue(AddrInst->getOperand(0), Scale, Depth);
3686 }
3687 case Instruction::GetElementPtr: {
3688 // Scan the GEP. We check it if it contains constant offsets and at most
3689 // one variable offset.
3690 int VariableOperand = -1;
3691 unsigned VariableScale = 0;
3692
3693 int64_t ConstantOffset = 0;
3694 gep_type_iterator GTI = gep_type_begin(AddrInst);
3695 for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
3696 if (StructType *STy = GTI.getStructTypeOrNull()) {
3697 const StructLayout *SL = DL.getStructLayout(STy);
3698 unsigned Idx =
3699 cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
3700 ConstantOffset += SL->getElementOffset(Idx);
3701 } else {
3702 uint64_t TypeSize = DL.getTypeAllocSize(GTI.getIndexedType());
3703 if (ConstantInt *CI = dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
3704 ConstantOffset += CI->getSExtValue() * TypeSize;
3705 } else if (TypeSize) { // Scales of zero don't do anything.
3706 // We only allow one variable index at the moment.
3707 if (VariableOperand != -1)
3708 return false;
3709
3710 // Remember the variable index.
3711 VariableOperand = i;
3712 VariableScale = TypeSize;
3713 }
3714 }
3715 }
3716
3717 // A common case is for the GEP to only do a constant offset. In this case,
3718 // just add it to the disp field and check validity.
3719 if (VariableOperand == -1) {
3720 AddrMode.BaseOffs += ConstantOffset;
3721 if (ConstantOffset == 0 ||
3722 TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) {
3723 // Check to see if we can fold the base pointer in too.
3724 if (matchAddr(AddrInst->getOperand(0), Depth+1))
3725 return true;
3726 }
3727 AddrMode.BaseOffs -= ConstantOffset;
3728 return false;
3729 }
3730
3731 // Save the valid addressing mode in case we can't match.
3732 ExtAddrMode BackupAddrMode = AddrMode;
3733 unsigned OldSize = AddrModeInsts.size();
3734
3735 // See if the scale and offset amount is valid for this target.
3736 AddrMode.BaseOffs += ConstantOffset;
3737
3738 // Match the base operand of the GEP.
3739 if (!matchAddr(AddrInst->getOperand(0), Depth+1)) {
3740 // If it couldn't be matched, just stuff the value in a register.
3741 if (AddrMode.HasBaseReg) {
3742 AddrMode = BackupAddrMode;
3743 AddrModeInsts.resize(OldSize);
3744 return false;
3745 }
3746 AddrMode.HasBaseReg = true;
3747 AddrMode.BaseReg = AddrInst->getOperand(0);
3748 }
3749
3750 // Match the remaining variable portion of the GEP.
3751 if (!matchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
3752 Depth)) {
3753 // If it couldn't be matched, try stuffing the base into a register
3754 // instead of matching it, and retrying the match of the scale.
3755 AddrMode = BackupAddrMode;
3756 AddrModeInsts.resize(OldSize);
3757 if (AddrMode.HasBaseReg)
3758 return false;
3759 AddrMode.HasBaseReg = true;
3760 AddrMode.BaseReg = AddrInst->getOperand(0);
3761 AddrMode.BaseOffs += ConstantOffset;
3762 if (!matchScaledValue(AddrInst->getOperand(VariableOperand),
3763 VariableScale, Depth)) {
3764 // If even that didn't work, bail.
3765 AddrMode = BackupAddrMode;
3766 AddrModeInsts.resize(OldSize);
3767 return false;
3768 }
3769 }
3770
3771 return true;
3772 }
3773 case Instruction::SExt:
3774 case Instruction::ZExt: {
3775 Instruction *Ext = dyn_cast<Instruction>(AddrInst);
3776 if (!Ext)
3777 return false;
3778
3779 // Try to move this ext out of the way of the addressing mode.
3780 // Ask for a method for doing so.
3781 TypePromotionHelper::Action TPH =
3782 TypePromotionHelper::getAction(Ext, InsertedInsts, TLI, PromotedInsts);
3783 if (!TPH)
3784 return false;
3785
3786 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
3787 TPT.getRestorationPoint();
3788 unsigned CreatedInstsCost = 0;
3789 unsigned ExtCost = !TLI.isExtFree(Ext);
3790 Value *PromotedOperand =
3791 TPH(Ext, TPT, PromotedInsts, CreatedInstsCost, nullptr, nullptr, TLI);
3792 // SExt has been moved away.
3793 // Thus either it will be rematched later in the recursive calls or it is
3794 // gone. Anyway, we must not fold it into the addressing mode at this point.
3795 // E.g.,
3796 // op = add opnd, 1
3797 // idx = ext op
3798 // addr = gep base, idx
3799 // is now:
3800 // promotedOpnd = ext opnd <- no match here
3801 // op = promoted_add promotedOpnd, 1 <- match (later in recursive calls)
3802 // addr = gep base, op <- match
3803 if (MovedAway)
3804 *MovedAway = true;
3805
3806 assert(PromotedOperand &&(static_cast <bool> (PromotedOperand && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedOperand && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3807, __extension__ __PRETTY_FUNCTION__))
3807 "TypePromotionHelper should have filtered out those cases")(static_cast <bool> (PromotedOperand && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedOperand && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 3807, __extension__ __PRETTY_FUNCTION__))
;
3808
3809 ExtAddrMode BackupAddrMode = AddrMode;
3810 unsigned OldSize = AddrModeInsts.size();
3811
3812 if (!matchAddr(PromotedOperand, Depth) ||
3813 // The total of the new cost is equal to the cost of the created
3814 // instructions.
3815 // The total of the old cost is equal to the cost of the extension plus
3816 // what we have saved in the addressing mode.
3817 !isPromotionProfitable(CreatedInstsCost,
3818 ExtCost + (AddrModeInsts.size() - OldSize),
3819 PromotedOperand)) {
3820 AddrMode = BackupAddrMode;
3821 AddrModeInsts.resize(OldSize);
3822 DEBUG(dbgs() << "Sign extension does not pay off: rollback\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Sign extension does not pay off: rollback\n"
; } } while (false)
;
3823 TPT.rollback(LastKnownGood);
3824 return false;
3825 }
3826 return true;
3827 }
3828 }
3829 return false;
3830}
3831
3832/// If we can, try to add the value of 'Addr' into the current addressing mode.
3833/// If Addr can't be added to AddrMode this returns false and leaves AddrMode
3834/// unmodified. This assumes that Addr is either a pointer type or intptr_t
3835/// for the target.
3836///
3837bool AddressingModeMatcher::matchAddr(Value *Addr, unsigned Depth) {
3838 // Start a transaction at this point that we will rollback if the matching
3839 // fails.
3840 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
3841 TPT.getRestorationPoint();
3842 if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
3843 // Fold in immediates if legal for the target.
3844 AddrMode.BaseOffs += CI->getSExtValue();
3845 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
3846 return true;
3847 AddrMode.BaseOffs -= CI->getSExtValue();
3848 } else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
3849 // If this is a global variable, try to fold it into the addressing mode.
3850 if (!AddrMode.BaseGV) {
3851 AddrMode.BaseGV = GV;
3852 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
3853 return true;
3854 AddrMode.BaseGV = nullptr;
3855 }
3856 } else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
3857 ExtAddrMode BackupAddrMode = AddrMode;
3858 unsigned OldSize = AddrModeInsts.size();
3859
3860 // Check to see if it is possible to fold this operation.
3861 bool MovedAway = false;
3862 if (matchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
3863 // This instruction may have been moved away. If so, there is nothing
3864 // to check here.
3865 if (MovedAway)
3866 return true;
3867 // Okay, it's possible to fold this. Check to see if it is actually
3868 // *profitable* to do so. We use a simple cost model to avoid increasing
3869 // register pressure too much.
3870 if (I->hasOneUse() ||
3871 isProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
3872 AddrModeInsts.push_back(I);
3873 return true;
3874 }
3875
3876 // It isn't profitable to do this, roll back.
3877 //cerr << "NOT FOLDING: " << *I;
3878 AddrMode = BackupAddrMode;
3879 AddrModeInsts.resize(OldSize);
3880 TPT.rollback(LastKnownGood);
3881 }
3882 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
3883 if (matchOperationAddr(CE, CE->getOpcode(), Depth))
3884 return true;
3885 TPT.rollback(LastKnownGood);
3886 } else if (isa<ConstantPointerNull>(Addr)) {
3887 // Null pointer gets folded without affecting the addressing mode.
3888 return true;
3889 }
3890
3891 // Worse case, the target should support [reg] addressing modes. :)
3892 if (!AddrMode.HasBaseReg) {
3893 AddrMode.HasBaseReg = true;
3894 AddrMode.BaseReg = Addr;
3895 // Still check for legality in case the target supports [imm] but not [i+r].
3896 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
3897 return true;
3898 AddrMode.HasBaseReg = false;
3899 AddrMode.BaseReg = nullptr;
3900 }
3901
3902 // If the base register is already taken, see if we can do [r+r].
3903 if (AddrMode.Scale == 0) {
3904 AddrMode.Scale = 1;
3905 AddrMode.ScaledReg = Addr;
3906 if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
3907 return true;
3908 AddrMode.Scale = 0;
3909 AddrMode.ScaledReg = nullptr;
3910 }
3911 // Couldn't match.
3912 TPT.rollback(LastKnownGood);
3913 return false;
3914}
3915
3916/// Check to see if all uses of OpVal by the specified inline asm call are due
3917/// to memory operands. If so, return true, otherwise return false.
3918static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
3919 const TargetLowering &TLI,
3920 const TargetRegisterInfo &TRI) {
3921 const Function *F = CI->getFunction();
3922 TargetLowering::AsmOperandInfoVector TargetConstraints =
3923 TLI.ParseConstraints(F->getParent()->getDataLayout(), &TRI,
3924 ImmutableCallSite(CI));
3925
3926 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
3927 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
3928
3929 // Compute the constraint code and ConstraintType to use.
3930 TLI.ComputeConstraintToUse(OpInfo, SDValue());
3931
3932 // If this asm operand is our Value*, and if it isn't an indirect memory
3933 // operand, we can't fold it!
3934 if (OpInfo.CallOperandVal == OpVal &&
3935 (OpInfo.ConstraintType != TargetLowering::C_Memory ||
3936 !OpInfo.isIndirect))
3937 return false;
3938 }
3939
3940 return true;
3941}
3942
3943// Max number of memory uses to look at before aborting the search to conserve
3944// compile time.
3945static constexpr int MaxMemoryUsesToScan = 20;
3946
3947/// Recursively walk all the uses of I until we find a memory use.
3948/// If we find an obviously non-foldable instruction, return true.
3949/// Add the ultimately found memory instructions to MemoryUses.
3950static bool FindAllMemoryUses(
3951 Instruction *I,
3952 SmallVectorImpl<std::pair<Instruction *, unsigned>> &MemoryUses,
3953 SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetLowering &TLI,
3954 const TargetRegisterInfo &TRI, int SeenInsts = 0) {
3955 // If we already considered this instruction, we're done.
3956 if (!ConsideredInsts.insert(I).second)
3957 return false;
3958
3959 // If this is an obviously unfoldable instruction, bail out.
3960 if (!MightBeFoldableInst(I))
3961 return true;
3962
3963 const bool OptSize = I->getFunction()->optForSize();
3964
3965 // Loop over all the uses, recursively processing them.
3966 for (Use &U : I->uses()) {
3967 // Conservatively return true if we're seeing a large number or a deep chain
3968 // of users. This avoids excessive compilation times in pathological cases.
3969 if (SeenInsts++ >= MaxMemoryUsesToScan)
3970 return true;
3971
3972 Instruction *UserI = cast<Instruction>(U.getUser());
3973 if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) {
3974 MemoryUses.push_back(std::make_pair(LI, U.getOperandNo()));
3975 continue;
3976 }
3977
3978 if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) {
3979 unsigned opNo = U.getOperandNo();
3980 if (opNo != StoreInst::getPointerOperandIndex())
3981 return true; // Storing addr, not into addr.
3982 MemoryUses.push_back(std::make_pair(SI, opNo));
3983 continue;
3984 }
3985
3986 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(UserI)) {
3987 unsigned opNo = U.getOperandNo();
3988 if (opNo != AtomicRMWInst::getPointerOperandIndex())
3989 return true; // Storing addr, not into addr.
3990 MemoryUses.push_back(std::make_pair(RMW, opNo));
3991 continue;
3992 }
3993
3994 if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(UserI)) {
3995 unsigned opNo = U.getOperandNo();
3996 if (opNo != AtomicCmpXchgInst::getPointerOperandIndex())
3997 return true; // Storing addr, not into addr.
3998 MemoryUses.push_back(std::make_pair(CmpX, opNo));
3999 continue;
4000 }
4001
4002 if (CallInst *CI = dyn_cast<CallInst>(UserI)) {
4003 // If this is a cold call, we can sink the addressing calculation into
4004 // the cold path. See optimizeCallInst
4005 if (!OptSize && CI->hasFnAttr(Attribute::Cold))
4006 continue;
4007
4008 InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue());
4009 if (!IA) return true;
4010
4011 // If this is a memory operand, we're cool, otherwise bail out.
4012 if (!IsOperandAMemoryOperand(CI, IA, I, TLI, TRI))
4013 return true;
4014 continue;
4015 }
4016
4017 if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI, TRI,
4018 SeenInsts))
4019 return true;
4020 }
4021
4022 return false;
4023}
4024
4025/// Return true if Val is already known to be live at the use site that we're
4026/// folding it into. If so, there is no cost to include it in the addressing
4027/// mode. KnownLive1 and KnownLive2 are two values that we know are live at the
4028/// instruction already.
4029bool AddressingModeMatcher::valueAlreadyLiveAtInst(Value *Val,Value *KnownLive1,
4030 Value *KnownLive2) {
4031 // If Val is either of the known-live values, we know it is live!
4032 if (Val == nullptr || Val == KnownLive1 || Val == KnownLive2)
4033 return true;
4034
4035 // All values other than instructions and arguments (e.g. constants) are live.
4036 if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true;
4037
4038 // If Val is a constant sized alloca in the entry block, it is live, this is
4039 // true because it is just a reference to the stack/frame pointer, which is
4040 // live for the whole function.
4041 if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
4042 if (AI->isStaticAlloca())
4043 return true;
4044
4045 // Check to see if this value is already used in the memory instruction's
4046 // block. If so, it's already live into the block at the very least, so we
4047 // can reasonably fold it.
4048 return Val->isUsedInBasicBlock(MemoryInst->getParent());
4049}
4050
4051/// It is possible for the addressing mode of the machine to fold the specified
4052/// instruction into a load or store that ultimately uses it.
4053/// However, the specified instruction has multiple uses.
4054/// Given this, it may actually increase register pressure to fold it
4055/// into the load. For example, consider this code:
4056///
4057/// X = ...
4058/// Y = X+1
4059/// use(Y) -> nonload/store
4060/// Z = Y+1
4061/// load Z
4062///
4063/// In this case, Y has multiple uses, and can be folded into the load of Z
4064/// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to
4065/// be live at the use(Y) line. If we don't fold Y into load Z, we use one
4066/// fewer register. Since Y can't be folded into "use(Y)" we don't increase the
4067/// number of computations either.
4068///
4069/// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If
4070/// X was live across 'load Z' for other reasons, we actually *would* want to
4071/// fold the addressing mode in the Z case. This would make Y die earlier.
4072bool AddressingModeMatcher::
4073isProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore,
4074 ExtAddrMode &AMAfter) {
4075 if (IgnoreProfitability) return true;
4076
4077 // AMBefore is the addressing mode before this instruction was folded into it,
4078 // and AMAfter is the addressing mode after the instruction was folded. Get
4079 // the set of registers referenced by AMAfter and subtract out those
4080 // referenced by AMBefore: this is the set of values which folding in this
4081 // address extends the lifetime of.
4082 //
4083 // Note that there are only two potential values being referenced here,
4084 // BaseReg and ScaleReg (global addresses are always available, as are any
4085 // folded immediates).
4086 Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;
4087
4088 // If the BaseReg or ScaledReg was referenced by the previous addrmode, their
4089 // lifetime wasn't extended by adding this instruction.
4090 if (valueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
4091 BaseReg = nullptr;
4092 if (valueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
4093 ScaledReg = nullptr;
4094
4095 // If folding this instruction (and it's subexprs) didn't extend any live
4096 // ranges, we're ok with it.
4097 if (!BaseReg && !ScaledReg)
4098 return true;
4099
4100 // If all uses of this instruction can have the address mode sunk into them,
4101 // we can remove the addressing mode and effectively trade one live register
4102 // for another (at worst.) In this context, folding an addressing mode into
4103 // the use is just a particularly nice way of sinking it.
4104 SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
4105 SmallPtrSet<Instruction*, 16> ConsideredInsts;
4106 if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI, TRI))
4107 return false; // Has a non-memory, non-foldable use!
4108
4109 // Now that we know that all uses of this instruction are part of a chain of
4110 // computation involving only operations that could theoretically be folded
4111 // into a memory use, loop over each of these memory operation uses and see
4112 // if they could *actually* fold the instruction. The assumption is that
4113 // addressing modes are cheap and that duplicating the computation involved
4114 // many times is worthwhile, even on a fastpath. For sinking candidates
4115 // (i.e. cold call sites), this serves as a way to prevent excessive code
4116 // growth since most architectures have some reasonable small and fast way to
4117 // compute an effective address. (i.e LEA on x86)
4118 SmallVector<Instruction*, 32> MatchedAddrModeInsts;
4119 for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) {
4120 Instruction *User = MemoryUses[i].first;
4121 unsigned OpNo = MemoryUses[i].second;
4122
4123 // Get the access type of this use. If the use isn't a pointer, we don't
4124 // know what it accesses.
4125 Value *Address = User->getOperand(OpNo);
4126 PointerType *AddrTy = dyn_cast<PointerType>(Address->getType());
4127 if (!AddrTy)
4128 return false;
4129 Type *AddressAccessTy = AddrTy->getElementType();
4130 unsigned AS = AddrTy->getAddressSpace();
4131
4132 // Do a match against the root of this address, ignoring profitability. This
4133 // will tell us if the addressing mode for the memory operation will
4134 // *actually* cover the shared instruction.
4135 ExtAddrMode Result;
4136 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4137 TPT.getRestorationPoint();
4138 AddressingModeMatcher Matcher(MatchedAddrModeInsts, TLI, TRI,
4139 AddressAccessTy, AS,
4140 MemoryInst, Result, InsertedInsts,
4141 PromotedInsts, TPT);
4142 Matcher.IgnoreProfitability = true;
4143 bool Success = Matcher.matchAddr(Address, 0);
4144 (void)Success; assert(Success && "Couldn't select *anything*?")(static_cast <bool> (Success && "Couldn't select *anything*?"
) ? void (0) : __assert_fail ("Success && \"Couldn't select *anything*?\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4144, __extension__ __PRETTY_FUNCTION__))
;
4145
4146 // The match was to check the profitability, the changes made are not
4147 // part of the original matcher. Therefore, they should be dropped
4148 // otherwise the original matcher will not present the right state.
4149 TPT.rollback(LastKnownGood);
4150
4151 // If the match didn't cover I, then it won't be shared by it.
4152 if (!is_contained(MatchedAddrModeInsts, I))
4153 return false;
4154
4155 MatchedAddrModeInsts.clear();
4156 }
4157
4158 return true;
4159}
4160
4161/// Return true if the specified values are defined in a
4162/// different basic block than BB.
4163static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
4164 if (Instruction *I = dyn_cast<Instruction>(V))
4165 return I->getParent() != BB;
4166 return false;
4167}
4168
4169/// Sink addressing mode computation immediate before MemoryInst if doing so
4170/// can be done without increasing register pressure. The need for the
4171/// register pressure constraint means this can end up being an all or nothing
4172/// decision for all uses of the same addressing computation.
4173///
4174/// Load and Store Instructions often have addressing modes that can do
4175/// significant amounts of computation. As such, instruction selection will try
4176/// to get the load or store to do as much computation as possible for the
4177/// program. The problem is that isel can only see within a single block. As
4178/// such, we sink as much legal addressing mode work into the block as possible.
4179///
4180/// This method is used to optimize both load/store and inline asms with memory
4181/// operands. It's also used to sink addressing computations feeding into cold
4182/// call sites into their (cold) basic block.
4183///
4184/// The motivation for handling sinking into cold blocks is that doing so can
4185/// both enable other address mode sinking (by satisfying the register pressure
4186/// constraint above), and reduce register pressure globally (by removing the
4187/// addressing mode computation from the fast path entirely.).
4188bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
4189 Type *AccessTy, unsigned AddrSpace) {
4190 Value *Repl = Addr;
4191
4192 // Try to collapse single-value PHI nodes. This is necessary to undo
4193 // unprofitable PRE transformations.
4194 SmallVector<Value*, 8> worklist;
4195 SmallPtrSet<Value*, 16> Visited;
4196 worklist.push_back(Addr);
4197
4198 // Use a worklist to iteratively look through PHI and select nodes, and
4199 // ensure that the addressing mode obtained from the non-PHI/select roots of
4200 // the graph are compatible.
4201 bool PhiOrSelectSeen = false;
4202 SmallVector<Instruction*, 16> AddrModeInsts;
4203 const SimplifyQuery SQ(*DL, TLInfo);
4204 AddressingModeCombiner AddrModes(SQ, { Addr, MemoryInst->getParent() });
4205 TypePromotionTransaction TPT(RemovedInsts);
4206 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4207 TPT.getRestorationPoint();
4208 while (!worklist.empty()) {
1
Loop condition is true. Entering loop body
7
Loop condition is true. Entering loop body
13
Loop condition is true. Entering loop body
19
Loop condition is true. Entering loop body
4209 Value *V = worklist.back();
4210 worklist.pop_back();
4211
4212 // We allow traversing cyclic Phi nodes.
4213 // In case of success after this loop we ensure that traversing through
4214 // Phi nodes ends up with all cases to compute address of the form
4215 // BaseGV + Base + Scale * Index + Offset
4216 // where Scale and Offset are constans and BaseGV, Base and Index
4217 // are exactly the same Values in all cases.
4218 // It means that BaseGV, Scale and Offset dominate our memory instruction
4219 // and have the same value as they had in address computation represented
4220 // as Phi. So we can safely sink address computation to memory instruction.
4221 if (!Visited.insert(V).second)
2
Assuming the condition is false
3
Taking false branch
8
Assuming the condition is false
9
Taking false branch
14
Assuming the condition is false
15
Taking false branch
20
Assuming the condition is false
21
Taking false branch
4222 continue;
4223
4224 // For a PHI node, push all of its incoming values.
4225 if (PHINode *P = dyn_cast<PHINode>(V)) {
4
Taking false branch
10
Taking false branch
16
Taking false branch
22
Taking false branch
4226 for (Value *IncValue : P->incoming_values())
4227 worklist.push_back(IncValue);
4228 PhiOrSelectSeen = true;
4229 continue;
4230 }
4231 // Similar for select.
4232 if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
5
Taking false branch
11
Taking false branch
17
Taking false branch
23
Taking false branch
4233 worklist.push_back(SI->getFalseValue());
4234 worklist.push_back(SI->getTrueValue());
4235 PhiOrSelectSeen = true;
4236 continue;
4237 }
4238
4239 // For non-PHIs, determine the addressing mode being computed. Note that
4240 // the result may differ depending on what other uses our candidate
4241 // addressing instructions might have.
4242 AddrModeInsts.clear();
4243 ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
4244 V, AccessTy, AddrSpace, MemoryInst, AddrModeInsts, *TLI, *TRI,
4245 InsertedInsts, PromotedInsts, TPT);
4246 NewAddrMode.OriginalValue = V;
4247
4248 if (!AddrModes.addNewAddrMode(NewAddrMode))
6
Taking false branch
12
Taking false branch
18
Taking false branch
24
Taking true branch
4249 break;
25
Execution continues on line 4255
4250 }
4251
4252 // Try to combine the AddrModes we've collected. If we couldn't collect any,
4253 // or we have multiple but either couldn't combine them or combining them
4254 // wouldn't do anything useful, bail out now.
4255 if (!AddrModes.combineAddrModes()) {
26
Calling 'AddressingModeCombiner::combineAddrModes'
4256 TPT.rollback(LastKnownGood);
4257 return false;
4258 }
4259 TPT.commit();
4260
4261 // Get the combined AddrMode (or the only AddrMode, if we only had one).
4262 ExtAddrMode AddrMode = AddrModes.getAddrMode();
4263
4264 // If all the instructions matched are already in this BB, don't do anything.
4265 // If we saw a Phi node then it is not local definitely, and if we saw a select
4266 // then we want to push the address calculation past it even if it's already
4267 // in this BB.
4268 if (!PhiOrSelectSeen && none_of(AddrModeInsts, [&](Value *V) {
4269 return IsNonLocalValue(V, MemoryInst->getParent());
4270 })) {
4271 DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrMode << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Found local addrmode: "
<< AddrMode << "\n"; } } while (false)
;
4272 return false;
4273 }
4274
4275 // Insert this computation right after this user. Since our caller is
4276 // scanning from the top of the BB to the bottom, reuse of the expr are
4277 // guaranteed to happen later.
4278 IRBuilder<> Builder(MemoryInst);
4279
4280 // Now that we determined the addressing expression we want to use and know
4281 // that we have to sink it into this block. Check to see if we have already
4282 // done this for some other load/store instr in this block. If so, reuse
4283 // the computation. Before attempting reuse, check if the address is valid
4284 // as it may have been erased.
4285
4286 WeakTrackingVH SunkAddrVH = SunkAddrs[Addr];
4287
4288 Value * SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr;
4289 if (SunkAddr) {
4290 DEBUG(dbgs() << "CGP: Reusing nonlocal addrmode: " << AddrMode << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Reusing nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
4291 << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Reusing nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
4292 if (SunkAddr->getType() != Addr->getType())
4293 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
4294 } else if (AddrSinkUsingGEPs ||
4295 (!AddrSinkUsingGEPs.getNumOccurrences() && TM &&
4296 SubtargetInfo->useAA())) {
4297 // By default, we use the GEP-based method when AA is used later. This
4298 // prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
4299 DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrMode << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
4300 << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
4301 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
4302 Value *ResultPtr = nullptr, *ResultIndex = nullptr;
4303
4304 // First, find the pointer.
4305 if (AddrMode.BaseReg && AddrMode.BaseReg->getType()->isPointerTy()) {
4306 ResultPtr = AddrMode.BaseReg;
4307 AddrMode.BaseReg = nullptr;
4308 }
4309
4310 if (AddrMode.Scale && AddrMode.ScaledReg->getType()->isPointerTy()) {
4311 // We can't add more than one pointer together, nor can we scale a
4312 // pointer (both of which seem meaningless).
4313 if (ResultPtr || AddrMode.Scale != 1)
4314 return false;
4315
4316 ResultPtr = AddrMode.ScaledReg;
4317 AddrMode.Scale = 0;
4318 }
4319
4320 // It is only safe to sign extend the BaseReg if we know that the math
4321 // required to create it did not overflow before we extend it. Since
4322 // the original IR value was tossed in favor of a constant back when
4323 // the AddrMode was created we need to bail out gracefully if widths
4324 // do not match instead of extending it.
4325 //
4326 // (See below for code to add the scale.)
4327 if (AddrMode.Scale) {
4328 Type *ScaledRegTy = AddrMode.ScaledReg->getType();
4329 if (cast<IntegerType>(IntPtrTy)->getBitWidth() >
4330 cast<IntegerType>(ScaledRegTy)->getBitWidth())
4331 return false;
4332 }
4333
4334 if (AddrMode.BaseGV) {
4335 if (ResultPtr)
4336 return false;
4337
4338 ResultPtr = AddrMode.BaseGV;
4339 }
4340
4341 // If the real base value actually came from an inttoptr, then the matcher
4342 // will look through it and provide only the integer value. In that case,
4343 // use it here.
4344 if (!DL->isNonIntegralPointerType(Addr->getType())) {
4345 if (!ResultPtr && AddrMode.BaseReg) {
4346 ResultPtr = Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(),
4347 "sunkaddr");
4348 AddrMode.BaseReg = nullptr;
4349 } else if (!ResultPtr && AddrMode.Scale == 1) {
4350 ResultPtr = Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(),
4351 "sunkaddr");
4352 AddrMode.Scale = 0;
4353 }
4354 }
4355
4356 if (!ResultPtr &&
4357 !AddrMode.BaseReg && !AddrMode.Scale && !AddrMode.BaseOffs) {
4358 SunkAddr = Constant::getNullValue(Addr->getType());
4359 } else if (!ResultPtr) {
4360 return false;
4361 } else {
4362 Type *I8PtrTy =
4363 Builder.getInt8PtrTy(Addr->getType()->getPointerAddressSpace());
4364 Type *I8Ty = Builder.getInt8Ty();
4365
4366 // Start with the base register. Do this first so that subsequent address
4367 // matching finds it last, which will prevent it from trying to match it
4368 // as the scaled value in case it happens to be a mul. That would be
4369 // problematic if we've sunk a different mul for the scale, because then
4370 // we'd end up sinking both muls.
4371 if (AddrMode.BaseReg) {
4372 Value *V = AddrMode.BaseReg;
4373 if (V->getType() != IntPtrTy)
4374 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
4375
4376 ResultIndex = V;
4377 }
4378
4379 // Add the scale value.
4380 if (AddrMode.Scale) {
4381 Value *V = AddrMode.ScaledReg;
4382 if (V->getType() == IntPtrTy) {
4383 // done.
4384 } else {
4385 assert(cast<IntegerType>(IntPtrTy)->getBitWidth() <(static_cast <bool> (cast<IntegerType>(IntPtrTy)->
getBitWidth() < cast<IntegerType>(V->getType())->
getBitWidth() && "We can't transform if ScaledReg is too narrow"
) ? void (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4387, __extension__ __PRETTY_FUNCTION__))
4386 cast<IntegerType>(V->getType())->getBitWidth() &&(static_cast <bool> (cast<IntegerType>(IntPtrTy)->
getBitWidth() < cast<IntegerType>(V->getType())->
getBitWidth() && "We can't transform if ScaledReg is too narrow"
) ? void (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4387, __extension__ __PRETTY_FUNCTION__))
4387 "We can't transform if ScaledReg is too narrow")(static_cast <bool> (cast<IntegerType>(IntPtrTy)->
getBitWidth() < cast<IntegerType>(V->getType())->
getBitWidth() && "We can't transform if ScaledReg is too narrow"
) ? void (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4387, __extension__ __PRETTY_FUNCTION__))
;
4388 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
4389 }
4390
4391 if (AddrMode.Scale != 1)
4392 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
4393 "sunkaddr");
4394 if (ResultIndex)
4395 ResultIndex = Builder.CreateAdd(ResultIndex, V, "sunkaddr");
4396 else
4397 ResultIndex = V;
4398 }
4399
4400 // Add in the Base Offset if present.
4401 if (AddrMode.BaseOffs) {
4402 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
4403 if (ResultIndex) {
4404 // We need to add this separately from the scale above to help with
4405 // SDAG consecutive load/store merging.
4406 if (ResultPtr->getType() != I8PtrTy)
4407 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
4408 ResultPtr = Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
4409 }
4410
4411 ResultIndex = V;
4412 }
4413
4414 if (!ResultIndex) {
4415 SunkAddr = ResultPtr;
4416 } else {
4417 if (ResultPtr->getType() != I8PtrTy)
4418 ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
4419 SunkAddr = Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
4420 }
4421
4422 if (SunkAddr->getType() != Addr->getType())
4423 SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
4424 }
4425 } else {
4426 // We'd require a ptrtoint/inttoptr down the line, which we can't do for
4427 // non-integral pointers, so in that case bail out now.
4428 Type *BaseTy = AddrMode.BaseReg ? AddrMode.BaseReg->getType() : nullptr;
4429 Type *ScaleTy = AddrMode.Scale ? AddrMode.ScaledReg->getType() : nullptr;
4430 PointerType *BasePtrTy = dyn_cast_or_null<PointerType>(BaseTy);
4431 PointerType *ScalePtrTy = dyn_cast_or_null<PointerType>(ScaleTy);
4432 if (DL->isNonIntegralPointerType(Addr->getType()) ||
4433 (BasePtrTy && DL->isNonIntegralPointerType(BasePtrTy)) ||
4434 (ScalePtrTy && DL->isNonIntegralPointerType(ScalePtrTy)) ||
4435 (AddrMode.BaseGV &&
4436 DL->isNonIntegralPointerType(AddrMode.BaseGV->getType())))
4437 return false;
4438
4439 DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrMode << " for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
4440 << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
<< AddrMode << " for " << *MemoryInst <<
"\n"; } } while (false)
;
4441 Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
4442 Value *Result = nullptr;
4443
4444 // Start with the base register. Do this first so that subsequent address
4445 // matching finds it last, which will prevent it from trying to match it
4446 // as the scaled value in case it happens to be a mul. That would be
4447 // problematic if we've sunk a different mul for the scale, because then
4448 // we'd end up sinking both muls.
4449 if (AddrMode.BaseReg) {
4450 Value *V = AddrMode.BaseReg;
4451 if (V->getType()->isPointerTy())
4452 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
4453 if (V->getType() != IntPtrTy)
4454 V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
4455 Result = V;
4456 }
4457
4458 // Add the scale value.
4459 if (AddrMode.Scale) {
4460 Value *V = AddrMode.ScaledReg;
4461 if (V->getType() == IntPtrTy) {
4462 // done.
4463 } else if (V->getType()->isPointerTy()) {
4464 V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
4465 } else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
4466 cast<IntegerType>(V->getType())->getBitWidth()) {
4467 V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
4468 } else {
4469 // It is only safe to sign extend the BaseReg if we know that the math
4470 // required to create it did not overflow before we extend it. Since
4471 // the original IR value was tossed in favor of a constant back when
4472 // the AddrMode was created we need to bail out gracefully if widths
4473 // do not match instead of extending it.
4474 Instruction *I = dyn_cast_or_null<Instruction>(Result);
4475 if (I && (Result != AddrMode.BaseReg))
4476 I->eraseFromParent();
4477 return false;
4478 }
4479 if (AddrMode.Scale != 1)
4480 V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
4481 "sunkaddr");
4482 if (Result)
4483 Result = Builder.CreateAdd(Result, V, "sunkaddr");
4484 else
4485 Result = V;
4486 }
4487
4488 // Add in the BaseGV if present.
4489 if (AddrMode.BaseGV) {
4490 Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
4491 if (Result)
4492 Result = Builder.CreateAdd(Result, V, "sunkaddr");
4493 else
4494 Result = V;
4495 }
4496
4497 // Add in the Base Offset if present.
4498 if (AddrMode.BaseOffs) {
4499 Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
4500 if (Result)
4501 Result = Builder.CreateAdd(Result, V, "sunkaddr");
4502 else
4503 Result = V;
4504 }
4505
4506 if (!Result)
4507 SunkAddr = Constant::getNullValue(Addr->getType());
4508 else
4509 SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr");
4510 }
4511
4512 MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
4513 // Store the newly computed address into the cache. In the case we reused a
4514 // value, this should be idempotent.
4515 SunkAddrs[Addr] = WeakTrackingVH(SunkAddr);
4516
4517 // If we have no uses, recursively delete the value and all dead instructions
4518 // using it.
4519 if (Repl->use_empty()) {
4520 // This can cause recursive deletion, which can invalidate our iterator.
4521 // Use a WeakTrackingVH to hold onto it in case this happens.
4522 Value *CurValue = &*CurInstIterator;
4523 WeakTrackingVH IterHandle(CurValue);
4524 BasicBlock *BB = CurInstIterator->getParent();
4525
4526 RecursivelyDeleteTriviallyDeadInstructions(Repl, TLInfo);
4527
4528 if (IterHandle != CurValue) {
4529 // If the iterator instruction was recursively deleted, start over at the
4530 // start of the block.
4531 CurInstIterator = BB->begin();
4532 SunkAddrs.clear();
4533 }
4534 }
4535 ++NumMemoryInsts;
4536 return true;
4537}
4538
4539/// If there are any memory operands, use OptimizeMemoryInst to sink their
4540/// address computing into the block when possible / profitable.
4541bool CodeGenPrepare::optimizeInlineAsmInst(CallInst *CS) {
4542 bool MadeChange = false;
4543
4544 const TargetRegisterInfo *TRI =
4545 TM->getSubtargetImpl(*CS->getFunction())->getRegisterInfo();
4546 TargetLowering::AsmOperandInfoVector TargetConstraints =
4547 TLI->ParseConstraints(*DL, TRI, CS);
4548 unsigned ArgNo = 0;
4549 for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
4550 TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
4551
4552 // Compute the constraint code and ConstraintType to use.
4553 TLI->ComputeConstraintToUse(OpInfo, SDValue());
4554
4555 if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
4556 OpInfo.isIndirect) {
4557 Value *OpVal = CS->getArgOperand(ArgNo++);
4558 MadeChange |= optimizeMemoryInst(CS, OpVal, OpVal->getType(), ~0u);
4559 } else if (OpInfo.Type == InlineAsm::isInput)
4560 ArgNo++;
4561 }
4562
4563 return MadeChange;
4564}
4565
4566/// \brief Check if all the uses of \p Val are equivalent (or free) zero or
4567/// sign extensions.
4568static bool hasSameExtUse(Value *Val, const TargetLowering &TLI) {
4569 assert(!Val->use_empty() && "Input must have at least one use")(static_cast <bool> (!Val->use_empty() && "Input must have at least one use"
) ? void (0) : __assert_fail ("!Val->use_empty() && \"Input must have at least one use\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4569, __extension__ __PRETTY_FUNCTION__))
;
4570 const Instruction *FirstUser = cast<Instruction>(*Val->user_begin());
4571 bool IsSExt = isa<SExtInst>(FirstUser);
4572 Type *ExtTy = FirstUser->getType();
4573 for (const User *U : Val->users()) {
4574 const Instruction *UI = cast<Instruction>(U);
4575 if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI)))
4576 return false;
4577 Type *CurTy = UI->getType();
4578 // Same input and output types: Same instruction after CSE.
4579 if (CurTy == ExtTy)
4580 continue;
4581
4582 // If IsSExt is true, we are in this situation:
4583 // a = Val
4584 // b = sext ty1 a to ty2
4585 // c = sext ty1 a to ty3
4586 // Assuming ty2 is shorter than ty3, this could be turned into:
4587 // a = Val
4588 // b = sext ty1 a to ty2
4589 // c = sext ty2 b to ty3
4590 // However, the last sext is not free.
4591 if (IsSExt)
4592 return false;
4593
4594 // This is a ZExt, maybe this is free to extend from one type to another.
4595 // In that case, we would not account for a different use.
4596 Type *NarrowTy;
4597 Type *LargeTy;
4598 if (ExtTy->getScalarType()->getIntegerBitWidth() >
4599 CurTy->getScalarType()->getIntegerBitWidth()) {
4600 NarrowTy = CurTy;
4601 LargeTy = ExtTy;
4602 } else {
4603 NarrowTy = ExtTy;
4604 LargeTy = CurTy;
4605 }
4606
4607 if (!TLI.isZExtFree(NarrowTy, LargeTy))
4608 return false;
4609 }
4610 // All uses are the same or can be derived from one another for free.
4611 return true;
4612}
4613
4614/// \brief Try to speculatively promote extensions in \p Exts and continue
4615/// promoting through newly promoted operands recursively as far as doing so is
4616/// profitable. Save extensions profitably moved up, in \p ProfitablyMovedExts.
4617/// When some promotion happened, \p TPT contains the proper state to revert
4618/// them.
4619///
4620/// \return true if some promotion happened, false otherwise.
4621bool CodeGenPrepare::tryToPromoteExts(
4622 TypePromotionTransaction &TPT, const SmallVectorImpl<Instruction *> &Exts,
4623 SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
4624 unsigned CreatedInstsCost) {
4625 bool Promoted = false;
4626
4627 // Iterate over all the extensions to try to promote them.
4628 for (auto I : Exts) {
4629 // Early check if we directly have ext(load).
4630 if (isa<LoadInst>(I->getOperand(0))) {
4631 ProfitablyMovedExts.push_back(I);
4632 continue;
4633 }
4634
4635 // Check whether or not we want to do any promotion. The reason we have
4636 // this check inside the for loop is to catch the case where an extension
4637 // is directly fed by a load because in such case the extension can be moved
4638 // up without any promotion on its operands.
4639 if (!TLI || !TLI->enableExtLdPromotion() || DisableExtLdPromotion)
4640 return false;
4641
4642 // Get the action to perform the promotion.
4643 TypePromotionHelper::Action TPH =
4644 TypePromotionHelper::getAction(I, InsertedInsts, *TLI, PromotedInsts);
4645 // Check if we can promote.
4646 if (!TPH) {
4647 // Save the current extension as we cannot move up through its operand.
4648 ProfitablyMovedExts.push_back(I);
4649 continue;
4650 }
4651
4652 // Save the current state.
4653 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4654 TPT.getRestorationPoint();
4655 SmallVector<Instruction *, 4> NewExts;
4656 unsigned NewCreatedInstsCost = 0;
4657 unsigned ExtCost = !TLI->isExtFree(I);
4658 // Promote.
4659 Value *PromotedVal = TPH(I, TPT, PromotedInsts, NewCreatedInstsCost,
4660 &NewExts, nullptr, *TLI);
4661 assert(PromotedVal &&(static_cast <bool> (PromotedVal && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedVal && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4662, __extension__ __PRETTY_FUNCTION__))
4662 "TypePromotionHelper should have filtered out those cases")(static_cast <bool> (PromotedVal && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedVal && \"TypePromotionHelper should have filtered out those cases\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4662, __extension__ __PRETTY_FUNCTION__))
;
4663
4664 // We would be able to merge only one extension in a load.
4665 // Therefore, if we have more than 1 new extension we heuristically
4666 // cut this search path, because it means we degrade the code quality.
4667 // With exactly 2, the transformation is neutral, because we will merge
4668 // one extension but leave one. However, we optimistically keep going,
4669 // because the new extension may be removed too.
4670 long long TotalCreatedInstsCost = CreatedInstsCost + NewCreatedInstsCost;
4671 // FIXME: It would be possible to propagate a negative value instead of
4672 // conservatively ceiling it to 0.
4673 TotalCreatedInstsCost =
4674 std::max((long long)0, (TotalCreatedInstsCost - ExtCost));
4675 if (!StressExtLdPromotion &&
4676 (TotalCreatedInstsCost > 1 ||
4677 !isPromotedInstructionLegal(*TLI, *DL, PromotedVal))) {
4678 // This promotion is not profitable, rollback to the previous state, and
4679 // save the current extension in ProfitablyMovedExts as the latest
4680 // speculative promotion turned out to be unprofitable.
4681 TPT.rollback(LastKnownGood);
4682 ProfitablyMovedExts.push_back(I);
4683 continue;
4684 }
4685 // Continue promoting NewExts as far as doing so is profitable.
4686 SmallVector<Instruction *, 2> NewlyMovedExts;
4687 (void)tryToPromoteExts(TPT, NewExts, NewlyMovedExts, TotalCreatedInstsCost);
4688 bool NewPromoted = false;
4689 for (auto ExtInst : NewlyMovedExts) {
4690 Instruction *MovedExt = cast<Instruction>(ExtInst);
4691 Value *ExtOperand = MovedExt->getOperand(0);
4692 // If we have reached to a load, we need this extra profitability check
4693 // as it could potentially be merged into an ext(load).
4694 if (isa<LoadInst>(ExtOperand) &&
4695 !(StressExtLdPromotion || NewCreatedInstsCost <= ExtCost ||
4696 (ExtOperand->hasOneUse() || hasSameExtUse(ExtOperand, *TLI))))
4697 continue;
4698
4699 ProfitablyMovedExts.push_back(MovedExt);
4700 NewPromoted = true;
4701 }
4702
4703 // If none of speculative promotions for NewExts is profitable, rollback
4704 // and save the current extension (I) as the last profitable extension.
4705 if (!NewPromoted) {
4706 TPT.rollback(LastKnownGood);
4707 ProfitablyMovedExts.push_back(I);
4708 continue;
4709 }
4710 // The promotion is profitable.
4711 Promoted = true;
4712 }
4713 return Promoted;
4714}
4715
4716/// Merging redundant sexts when one is dominating the other.
4717bool CodeGenPrepare::mergeSExts(Function &F) {
4718 DominatorTree DT(F);
4719 bool Changed = false;
4720 for (auto &Entry : ValToSExtendedUses) {
4721 SExts &Insts = Entry.second;
4722 SExts CurPts;
4723 for (Instruction *Inst : Insts) {
4724 if (RemovedInsts.count(Inst) || !isa<SExtInst>(Inst) ||
4725 Inst->getOperand(0) != Entry.first)
4726 continue;
4727 bool inserted = false;
4728 for (auto &Pt : CurPts) {
4729 if (DT.dominates(Inst, Pt)) {
4730 Pt->replaceAllUsesWith(Inst);
4731 RemovedInsts.insert(Pt);
4732 Pt->removeFromParent();
4733 Pt = Inst;
4734 inserted = true;
4735 Changed = true;
4736 break;
4737 }
4738 if (!DT.dominates(Pt, Inst))
4739 // Give up if we need to merge in a common dominator as the
4740 // expermients show it is not profitable.
4741 continue;
4742 Inst->replaceAllUsesWith(Pt);
4743 RemovedInsts.insert(Inst);
4744 Inst->removeFromParent();
4745 inserted = true;
4746 Changed = true;
4747 break;
4748 }
4749 if (!inserted)
4750 CurPts.push_back(Inst);
4751 }
4752 }
4753 return Changed;
4754}
4755
4756/// Return true, if an ext(load) can be formed from an extension in
4757/// \p MovedExts.
4758bool CodeGenPrepare::canFormExtLd(
4759 const SmallVectorImpl<Instruction *> &MovedExts, LoadInst *&LI,
4760 Instruction *&Inst, bool HasPromoted) {
4761 for (auto *MovedExtInst : MovedExts) {
4762 if (isa<LoadInst>(MovedExtInst->getOperand(0))) {
4763 LI = cast<LoadInst>(MovedExtInst->getOperand(0));
4764 Inst = MovedExtInst;
4765 break;
4766 }
4767 }
4768 if (!LI)
4769 return false;
4770
4771 // If they're already in the same block, there's nothing to do.
4772 // Make the cheap checks first if we did not promote.
4773 // If we promoted, we need to check if it is indeed profitable.
4774 if (!HasPromoted && LI->getParent() == Inst->getParent())
4775 return false;
4776
4777 return TLI->isExtLoad(LI, Inst, *DL);
4778}
4779
4780/// Move a zext or sext fed by a load into the same basic block as the load,
4781/// unless conditions are unfavorable. This allows SelectionDAG to fold the
4782/// extend into the load.
4783///
4784/// E.g.,
4785/// \code
4786/// %ld = load i32* %addr
4787/// %add = add nuw i32 %ld, 4
4788/// %zext = zext i32 %add to i64
4789// \endcode
4790/// =>
4791/// \code
4792/// %ld = load i32* %addr
4793/// %zext = zext i32 %ld to i64
4794/// %add = add nuw i64 %zext, 4
4795/// \encode
4796/// Note that the promotion in %add to i64 is done in tryToPromoteExts(), which
4797/// allow us to match zext(load i32*) to i64.
4798///
4799/// Also, try to promote the computations used to obtain a sign extended
4800/// value used into memory accesses.
4801/// E.g.,
4802/// \code
4803/// a = add nsw i32 b, 3
4804/// d = sext i32 a to i64
4805/// e = getelementptr ..., i64 d
4806/// \endcode
4807/// =>
4808/// \code
4809/// f = sext i32 b to i64
4810/// a = add nsw i64 f, 3
4811/// e = getelementptr ..., i64 a
4812/// \endcode
4813///
4814/// \p Inst[in/out] the extension may be modified during the process if some
4815/// promotions apply.
4816bool CodeGenPrepare::optimizeExt(Instruction *&Inst) {
4817 // ExtLoad formation and address type promotion infrastructure requires TLI to
4818 // be effective.
4819 if (!TLI)
4820 return false;
4821
4822 bool AllowPromotionWithoutCommonHeader = false;
4823 /// See if it is an interesting sext operations for the address type
4824 /// promotion before trying to promote it, e.g., the ones with the right
4825 /// type and used in memory accesses.
4826 bool ATPConsiderable = TTI->shouldConsiderAddressTypePromotion(
4827 *Inst, AllowPromotionWithoutCommonHeader);
4828 TypePromotionTransaction TPT(RemovedInsts);
4829 TypePromotionTransaction::ConstRestorationPt LastKnownGood =
4830 TPT.getRestorationPoint();
4831 SmallVector<Instruction *, 1> Exts;
4832 SmallVector<Instruction *, 2> SpeculativelyMovedExts;
4833 Exts.push_back(Inst);
4834
4835 bool HasPromoted = tryToPromoteExts(TPT, Exts, SpeculativelyMovedExts);
4836
4837 // Look for a load being extended.
4838 LoadInst *LI = nullptr;
4839 Instruction *ExtFedByLoad;
4840
4841 // Try to promote a chain of computation if it allows to form an extended
4842 // load.
4843 if (canFormExtLd(SpeculativelyMovedExts, LI, ExtFedByLoad, HasPromoted)) {
4844 assert(LI && ExtFedByLoad && "Expect a valid load and extension")(static_cast <bool> (LI && ExtFedByLoad &&
"Expect a valid load and extension") ? void (0) : __assert_fail
("LI && ExtFedByLoad && \"Expect a valid load and extension\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4844, __extension__ __PRETTY_FUNCTION__))
;
4845 TPT.commit();
4846 // Move the extend into the same block as the load
4847 ExtFedByLoad->moveAfter(LI);
4848 // CGP does not check if the zext would be speculatively executed when moved
4849 // to the same basic block as the load. Preserving its original location
4850 // would pessimize the debugging experience, as well as negatively impact
4851 // the quality of sample pgo. We don't want to use "line 0" as that has a
4852 // size cost in the line-table section and logically the zext can be seen as
4853 // part of the load. Therefore we conservatively reuse the same debug
4854 // location for the load and the zext.
4855 ExtFedByLoad->setDebugLoc(LI->getDebugLoc());
4856 ++NumExtsMoved;
4857 Inst = ExtFedByLoad;
4858 return true;
4859 }
4860
4861 // Continue promoting SExts if known as considerable depending on targets.
4862 if (ATPConsiderable &&
4863 performAddressTypePromotion(Inst, AllowPromotionWithoutCommonHeader,
4864 HasPromoted, TPT, SpeculativelyMovedExts))
4865 return true;
4866
4867 TPT.rollback(LastKnownGood);
4868 return false;
4869}
4870
4871// Perform address type promotion if doing so is profitable.
4872// If AllowPromotionWithoutCommonHeader == false, we should find other sext
4873// instructions that sign extended the same initial value. However, if
4874// AllowPromotionWithoutCommonHeader == true, we expect promoting the
4875// extension is just profitable.
4876bool CodeGenPrepare::performAddressTypePromotion(
4877 Instruction *&Inst, bool AllowPromotionWithoutCommonHeader,
4878 bool HasPromoted, TypePromotionTransaction &TPT,
4879 SmallVectorImpl<Instruction *> &SpeculativelyMovedExts) {
4880 bool Promoted = false;
4881 SmallPtrSet<Instruction *, 1> UnhandledExts;
4882 bool AllSeenFirst = true;
4883 for (auto I : SpeculativelyMovedExts) {
4884 Value *HeadOfChain = I->getOperand(0);
4885 DenseMap<Value *, Instruction *>::iterator AlreadySeen =
4886 SeenChainsForSExt.find(HeadOfChain);
4887 // If there is an unhandled SExt which has the same header, try to promote
4888 // it as well.
4889 if (AlreadySeen != SeenChainsForSExt.end()) {
4890 if (AlreadySeen->second != nullptr)
4891 UnhandledExts.insert(AlreadySeen->second);
4892 AllSeenFirst = false;
4893 }
4894 }
4895
4896 if (!AllSeenFirst || (AllowPromotionWithoutCommonHeader &&
4897 SpeculativelyMovedExts.size() == 1)) {
4898 TPT.commit();
4899 if (HasPromoted)
4900 Promoted = true;
4901 for (auto I : SpeculativelyMovedExts) {
4902 Value *HeadOfChain = I->getOperand(0);
4903 SeenChainsForSExt[HeadOfChain] = nullptr;
4904 ValToSExtendedUses[HeadOfChain].push_back(I);
4905 }
4906 // Update Inst as promotion happen.
4907 Inst = SpeculativelyMovedExts.pop_back_val();
4908 } else {
4909 // This is the first chain visited from the header, keep the current chain
4910 // as unhandled. Defer to promote this until we encounter another SExt
4911 // chain derived from the same header.
4912 for (auto I : SpeculativelyMovedExts) {
4913 Value *HeadOfChain = I->getOperand(0);
4914 SeenChainsForSExt[HeadOfChain] = Inst;
4915 }
4916 return false;
4917 }
4918
4919 if (!AllSeenFirst && !UnhandledExts.empty())
4920 for (auto VisitedSExt : UnhandledExts) {
4921 if (RemovedInsts.count(VisitedSExt))
4922 continue;
4923 TypePromotionTransaction TPT(RemovedInsts);
4924 SmallVector<Instruction *, 1> Exts;
4925 SmallVector<Instruction *, 2> Chains;
4926 Exts.push_back(VisitedSExt);
4927 bool HasPromoted = tryToPromoteExts(TPT, Exts, Chains);
4928 TPT.commit();
4929 if (HasPromoted)
4930 Promoted = true;
4931 for (auto I : Chains) {
4932 Value *HeadOfChain = I->getOperand(0);
4933 // Mark this as handled.
4934 SeenChainsForSExt[HeadOfChain] = nullptr;
4935 ValToSExtendedUses[HeadOfChain].push_back(I);
4936 }
4937 }
4938 return Promoted;
4939}
4940
4941bool CodeGenPrepare::optimizeExtUses(Instruction *I) {
4942 BasicBlock *DefBB = I->getParent();
4943
4944 // If the result of a {s|z}ext and its source are both live out, rewrite all
4945 // other uses of the source with result of extension.
4946 Value *Src = I->getOperand(0);
4947 if (Src->hasOneUse())
4948 return false;
4949
4950 // Only do this xform if truncating is free.
4951 if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
4952 return false;
4953
4954 // Only safe to perform the optimization if the source is also defined in
4955 // this block.
4956 if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
4957 return false;
4958
4959 bool DefIsLiveOut = false;
4960 for (User *U : I->users()) {
4961 Instruction *UI = cast<Instruction>(U);
4962
4963 // Figure out which BB this ext is used in.
4964 BasicBlock *UserBB = UI->getParent();
4965 if (UserBB == DefBB) continue;
4966 DefIsLiveOut = true;
4967 break;
4968 }
4969 if (!DefIsLiveOut)
4970 return false;
4971
4972 // Make sure none of the uses are PHI nodes.
4973 for (User *U : Src->users()) {
4974 Instruction *UI = cast<Instruction>(U);
4975 BasicBlock *UserBB = UI->getParent();
4976 if (UserBB == DefBB) continue;
4977 // Be conservative. We don't want this xform to end up introducing
4978 // reloads just before load / store instructions.
4979 if (isa<PHINode>(UI) || isa<LoadInst>(UI) || isa<StoreInst>(UI))
4980 return false;
4981 }
4982
4983 // InsertedTruncs - Only insert one trunc in each block once.
4984 DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
4985
4986 bool MadeChange = false;
4987 for (Use &U : Src->uses()) {
4988 Instruction *User = cast<Instruction>(U.getUser());
4989
4990 // Figure out which BB this ext is used in.
4991 BasicBlock *UserBB = User->getParent();
4992 if (UserBB == DefBB) continue;
4993
4994 // Both src and def are live in this block. Rewrite the use.
4995 Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
4996
4997 if (!InsertedTrunc) {
4998 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
4999 assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
(0) : __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 4999, __extension__ __PRETTY_FUNCTION__))
;
5000 InsertedTrunc = new TruncInst(I, Src->getType(), "", &*InsertPt);
5001 InsertedInsts.insert(InsertedTrunc);
5002 }
5003
5004 // Replace a use of the {s|z}ext source with a use of the result.
5005 U = InsertedTrunc;
5006 ++NumExtUses;
5007 MadeChange = true;
5008 }
5009
5010 return MadeChange;
5011}
5012
5013// Find loads whose uses only use some of the loaded value's bits. Add an "and"
5014// just after the load if the target can fold this into one extload instruction,
5015// with the hope of eliminating some of the other later "and" instructions using
5016// the loaded value. "and"s that are made trivially redundant by the insertion
5017// of the new "and" are removed by this function, while others (e.g. those whose
5018// path from the load goes through a phi) are left for isel to potentially
5019// remove.
5020//
5021// For example:
5022//
5023// b0:
5024// x = load i32
5025// ...
5026// b1:
5027// y = and x, 0xff
5028// z = use y
5029//
5030// becomes:
5031//
5032// b0:
5033// x = load i32
5034// x' = and x, 0xff
5035// ...
5036// b1:
5037// z = use x'
5038//
5039// whereas:
5040//
5041// b0:
5042// x1 = load i32
5043// ...
5044// b1:
5045// x2 = load i32
5046// ...
5047// b2:
5048// x = phi x1, x2
5049// y = and x, 0xff
5050//
5051// becomes (after a call to optimizeLoadExt for each load):
5052//
5053// b0:
5054// x1 = load i32
5055// x1' = and x1, 0xff
5056// ...
5057// b1:
5058// x2 = load i32
5059// x2' = and x2, 0xff
5060// ...
5061// b2:
5062// x = phi x1', x2'
5063// y = and x, 0xff
5064bool CodeGenPrepare::optimizeLoadExt(LoadInst *Load) {
5065 if (!Load->isSimple() ||
5066 !(Load->getType()->isIntegerTy() || Load->getType()->isPointerTy()))
5067 return false;
5068
5069 // Skip loads we've already transformed.
5070 if (Load->hasOneUse() &&
5071 InsertedInsts.count(cast<Instruction>(*Load->user_begin())))
5072 return false;
5073
5074 // Look at all uses of Load, looking through phis, to determine how many bits
5075 // of the loaded value are needed.
5076 SmallVector<Instruction *, 8> WorkList;
5077 SmallPtrSet<Instruction *, 16> Visited;
5078 SmallVector<Instruction *, 8> AndsToMaybeRemove;
5079 for (auto *U : Load->users())
5080 WorkList.push_back(cast<Instruction>(U));
5081
5082 EVT LoadResultVT = TLI->getValueType(*DL, Load->getType());
5083 unsigned BitWidth = LoadResultVT.getSizeInBits();
5084 APInt DemandBits(BitWidth, 0);
5085 APInt WidestAndBits(BitWidth, 0);
5086
5087 while (!WorkList.empty()) {
5088 Instruction *I = WorkList.back();
5089 WorkList.pop_back();
5090
5091 // Break use-def graph loops.
5092 if (!Visited.insert(I).second)
5093 continue;
5094
5095 // For a PHI node, push all of its users.
5096 if (auto *Phi = dyn_cast<PHINode>(I)) {
5097 for (auto *U : Phi->users())
5098 WorkList.push_back(cast<Instruction>(U));
5099 continue;
5100 }
5101
5102 switch (I->getOpcode()) {
5103 case Instruction::And: {
5104 auto *AndC = dyn_cast<ConstantInt>(I->getOperand(1));
5105 if (!AndC)
5106 return false;
5107 APInt AndBits = AndC->getValue();
5108 DemandBits |= AndBits;
5109 // Keep track of the widest and mask we see.
5110 if (AndBits.ugt(WidestAndBits))
5111 WidestAndBits = AndBits;
5112 if (AndBits == WidestAndBits && I->getOperand(0) == Load)
5113 AndsToMaybeRemove.push_back(I);
5114 break;
5115 }
5116
5117 case Instruction::Shl: {
5118 auto *ShlC = dyn_cast<ConstantInt>(I->getOperand(1));
5119 if (!ShlC)
5120 return false;
5121 uint64_t ShiftAmt = ShlC->getLimitedValue(BitWidth - 1);
5122 DemandBits.setLowBits(BitWidth - ShiftAmt);
5123 break;
5124 }
5125
5126 case Instruction::Trunc: {
5127 EVT TruncVT = TLI->getValueType(*DL, I->getType());
5128 unsigned TruncBitWidth = TruncVT.getSizeInBits();
5129 DemandBits.setLowBits(TruncBitWidth);
5130 break;
5131 }
5132
5133 default:
5134 return false;
5135 }
5136 }
5137
5138 uint32_t ActiveBits = DemandBits.getActiveBits();
5139 // Avoid hoisting (and (load x) 1) since it is unlikely to be folded by the
5140 // target even if isLoadExtLegal says an i1 EXTLOAD is valid. For example,
5141 // for the AArch64 target isLoadExtLegal(ZEXTLOAD, i32, i1) returns true, but
5142 // (and (load x) 1) is not matched as a single instruction, rather as a LDR
5143 // followed by an AND.
5144 // TODO: Look into removing this restriction by fixing backends to either
5145 // return false for isLoadExtLegal for i1 or have them select this pattern to
5146 // a single instruction.
5147 //
5148 // Also avoid hoisting if we didn't see any ands with the exact DemandBits
5149 // mask, since these are the only ands that will be removed by isel.
5150 if (ActiveBits <= 1 || !DemandBits.isMask(ActiveBits) ||
5151 WidestAndBits != DemandBits)
5152 return false;
5153
5154 LLVMContext &Ctx = Load->getType()->getContext();
5155 Type *TruncTy = Type::getIntNTy(Ctx, ActiveBits);
5156 EVT TruncVT = TLI->getValueType(*DL, TruncTy);
5157
5158 // Reject cases that won't be matched as extloads.
5159 if (!LoadResultVT.bitsGT(TruncVT) || !TruncVT.isRound() ||
5160 !TLI->isLoadExtLegal(ISD::ZEXTLOAD, LoadResultVT, TruncVT))
5161 return false;
5162
5163 IRBuilder<> Builder(Load->getNextNode());
5164 auto *NewAnd = dyn_cast<Instruction>(
5165 Builder.CreateAnd(Load, ConstantInt::get(Ctx, DemandBits)));
5166 // Mark this instruction as "inserted by CGP", so that other
5167 // optimizations don't touch it.
5168 InsertedInsts.insert(NewAnd);
5169
5170 // Replace all uses of load with new and (except for the use of load in the
5171 // new and itself).
5172 Load->replaceAllUsesWith(NewAnd);
5173 NewAnd->setOperand(0, Load);
5174
5175 // Remove any and instructions that are now redundant.
5176 for (auto *And : AndsToMaybeRemove)
5177 // Check that the and mask is the same as the one we decided to put on the
5178 // new and.
5179 if (cast<ConstantInt>(And->getOperand(1))->getValue() == DemandBits) {
5180 And->replaceAllUsesWith(NewAnd);
5181 if (&*CurInstIterator == And)
5182 CurInstIterator = std::next(And->getIterator());
5183 And->eraseFromParent();
5184 ++NumAndUses;
5185 }
5186
5187 ++NumAndsAdded;
5188 return true;
5189}
5190
5191/// Check if V (an operand of a select instruction) is an expensive instruction
5192/// that is only used once.
5193static bool sinkSelectOperand(const TargetTransformInfo *TTI, Value *V) {
5194 auto *I = dyn_cast<Instruction>(V);
5195 // If it's safe to speculatively execute, then it should not have side
5196 // effects; therefore, it's safe to sink and possibly *not* execute.
5197 return I && I->hasOneUse() && isSafeToSpeculativelyExecute(I) &&
5198 TTI->getUserCost(I) >= TargetTransformInfo::TCC_Expensive;
5199}
5200
5201/// Returns true if a SelectInst should be turned into an explicit branch.
5202static bool isFormingBranchFromSelectProfitable(const TargetTransformInfo *TTI,
5203 const TargetLowering *TLI,
5204 SelectInst *SI) {
5205 // If even a predictable select is cheap, then a branch can't be cheaper.
5206 if (!TLI->isPredictableSelectExpensive())
5207 return false;
5208
5209 // FIXME: This should use the same heuristics as IfConversion to determine
5210 // whether a select is better represented as a branch.
5211
5212 // If metadata tells us that the select condition is obviously predictable,
5213 // then we want to replace the select with a branch.
5214 uint64_t TrueWeight, FalseWeight;
5215 if (SI->extractProfMetadata(TrueWeight, FalseWeight)) {
5216 uint64_t Max = std::max(TrueWeight, FalseWeight);
5217 uint64_t Sum = TrueWeight + FalseWeight;
5218 if (Sum != 0) {
5219 auto Probability = BranchProbability::getBranchProbability(Max, Sum);
5220 if (Probability > TLI->getPredictableBranchThreshold())
5221 return true;
5222 }
5223 }
5224
5225 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
5226
5227 // If a branch is predictable, an out-of-order CPU can avoid blocking on its
5228 // comparison condition. If the compare has more than one use, there's
5229 // probably another cmov or setcc around, so it's not worth emitting a branch.
5230 if (!Cmp || !Cmp->hasOneUse())
5231 return false;
5232
5233 // If either operand of the select is expensive and only needed on one side
5234 // of the select, we should form a branch.
5235 if (sinkSelectOperand(TTI, SI->getTrueValue()) ||
5236 sinkSelectOperand(TTI, SI->getFalseValue()))
5237 return true;
5238
5239 return false;
5240}
5241
5242/// If \p isTrue is true, return the true value of \p SI, otherwise return
5243/// false value of \p SI. If the true/false value of \p SI is defined by any
5244/// select instructions in \p Selects, look through the defining select
5245/// instruction until the true/false value is not defined in \p Selects.
5246static Value *getTrueOrFalseValue(
5247 SelectInst *SI, bool isTrue,
5248 const SmallPtrSet<const Instruction *, 2> &Selects) {
5249 Value *V;
5250
5251 for (SelectInst *DefSI = SI; DefSI != nullptr && Selects.count(DefSI);
5252 DefSI = dyn_cast<SelectInst>(V)) {
5253 assert(DefSI->getCondition() == SI->getCondition() &&(static_cast <bool> (DefSI->getCondition() == SI->
getCondition() && "The condition of DefSI does not match with SI"
) ? void (0) : __assert_fail ("DefSI->getCondition() == SI->getCondition() && \"The condition of DefSI does not match with SI\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5254, __extension__ __PRETTY_FUNCTION__))
5254 "The condition of DefSI does not match with SI")(static_cast <bool> (DefSI->getCondition() == SI->
getCondition() && "The condition of DefSI does not match with SI"
) ? void (0) : __assert_fail ("DefSI->getCondition() == SI->getCondition() && \"The condition of DefSI does not match with SI\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5254, __extension__ __PRETTY_FUNCTION__))
;
5255 V = (isTrue ? DefSI->getTrueValue() : DefSI->getFalseValue());
5256 }
5257 return V;
5258}
5259
5260/// If we have a SelectInst that will likely profit from branch prediction,
5261/// turn it into a branch.
5262bool CodeGenPrepare::optimizeSelectInst(SelectInst *SI) {
5263 // Find all consecutive select instructions that share the same condition.
5264 SmallVector<SelectInst *, 2> ASI;
5265 ASI.push_back(SI);
5266 for (BasicBlock::iterator It = ++BasicBlock::iterator(SI);
5267 It != SI->getParent()->end(); ++It) {
5268 SelectInst *I = dyn_cast<SelectInst>(&*It);
5269 if (I && SI->getCondition() == I->getCondition()) {
5270 ASI.push_back(I);
5271 } else {
5272 break;
5273 }
5274 }
5275
5276 SelectInst *LastSI = ASI.back();
5277 // Increment the current iterator to skip all the rest of select instructions
5278 // because they will be either "not lowered" or "all lowered" to branch.
5279 CurInstIterator = std::next(LastSI->getIterator());
5280
5281 bool VectorCond = !SI->getCondition()->getType()->isIntegerTy(1);
5282
5283 // Can we convert the 'select' to CF ?
5284 if (DisableSelectToBranch || OptSize || !TLI || VectorCond ||
5285 SI->getMetadata(LLVMContext::MD_unpredictable))
5286 return false;
5287
5288 TargetLowering::SelectSupportKind SelectKind;
5289 if (VectorCond)
5290 SelectKind = TargetLowering::VectorMaskSelect;
5291 else if (SI->getType()->isVectorTy())
5292 SelectKind = TargetLowering::ScalarCondVectorVal;
5293 else
5294 SelectKind = TargetLowering::ScalarValSelect;
5295
5296 if (TLI->isSelectSupported(SelectKind) &&
5297 !isFormingBranchFromSelectProfitable(TTI, TLI, SI))
5298 return false;
5299
5300 ModifiedDT = true;
5301
5302 // Transform a sequence like this:
5303 // start:
5304 // %cmp = cmp uge i32 %a, %b
5305 // %sel = select i1 %cmp, i32 %c, i32 %d
5306 //
5307 // Into:
5308 // start:
5309 // %cmp = cmp uge i32 %a, %b
5310 // br i1 %cmp, label %select.true, label %select.false
5311 // select.true:
5312 // br label %select.end
5313 // select.false:
5314 // br label %select.end
5315 // select.end:
5316 // %sel = phi i32 [ %c, %select.true ], [ %d, %select.false ]
5317 //
5318 // In addition, we may sink instructions that produce %c or %d from
5319 // the entry block into the destination(s) of the new branch.
5320 // If the true or false blocks do not contain a sunken instruction, that
5321 // block and its branch may be optimized away. In that case, one side of the
5322 // first branch will point directly to select.end, and the corresponding PHI
5323 // predecessor block will be the start block.
5324
5325 // First, we split the block containing the select into 2 blocks.
5326 BasicBlock *StartBlock = SI->getParent();
5327 BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(LastSI));
5328 BasicBlock *EndBlock = StartBlock->splitBasicBlock(SplitPt, "select.end");
5329
5330 // Delete the unconditional branch that was just created by the split.
5331 StartBlock->getTerminator()->eraseFromParent();
5332
5333 // These are the new basic blocks for the conditional branch.
5334 // At least one will become an actual new basic block.
5335 BasicBlock *TrueBlock = nullptr;
5336 BasicBlock *FalseBlock = nullptr;
5337 BranchInst *TrueBranch = nullptr;
5338 BranchInst *FalseBranch = nullptr;
5339
5340 // Sink expensive instructions into the conditional blocks to avoid executing
5341 // them speculatively.
5342 for (SelectInst *SI : ASI) {
5343 if (sinkSelectOperand(TTI, SI->getTrueValue())) {
5344 if (TrueBlock == nullptr) {
5345 TrueBlock = BasicBlock::Create(SI->getContext(), "select.true.sink",
5346 EndBlock->getParent(), EndBlock);
5347 TrueBranch = BranchInst::Create(EndBlock, TrueBlock);
5348 }
5349 auto *TrueInst = cast<Instruction>(SI->getTrueValue());
5350 TrueInst->moveBefore(TrueBranch);
5351 }
5352 if (sinkSelectOperand(TTI, SI->getFalseValue())) {
5353 if (FalseBlock == nullptr) {
5354 FalseBlock = BasicBlock::Create(SI->getContext(), "select.false.sink",
5355 EndBlock->getParent(), EndBlock);
5356 FalseBranch = BranchInst::Create(EndBlock, FalseBlock);
5357 }
5358 auto *FalseInst = cast<Instruction>(SI->getFalseValue());
5359 FalseInst->moveBefore(FalseBranch);
5360 }
5361 }
5362
5363 // If there was nothing to sink, then arbitrarily choose the 'false' side
5364 // for a new input value to the PHI.
5365 if (TrueBlock == FalseBlock) {
5366 assert(TrueBlock == nullptr &&(static_cast <bool> (TrueBlock == nullptr && "Unexpected basic block transform while optimizing select"
) ? void (0) : __assert_fail ("TrueBlock == nullptr && \"Unexpected basic block transform while optimizing select\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5367, __extension__ __PRETTY_FUNCTION__))
5367 "Unexpected basic block transform while optimizing select")(static_cast <bool> (TrueBlock == nullptr && "Unexpected basic block transform while optimizing select"
) ? void (0) : __assert_fail ("TrueBlock == nullptr && \"Unexpected basic block transform while optimizing select\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5367, __extension__ __PRETTY_FUNCTION__))
;
5368
5369 FalseBlock = BasicBlock::Create(SI->getContext(), "select.false",
5370 EndBlock->getParent(), EndBlock);
5371 BranchInst::Create(EndBlock, FalseBlock);
5372 }
5373
5374 // Insert the real conditional branch based on the original condition.
5375 // If we did not create a new block for one of the 'true' or 'false' paths
5376 // of the condition, it means that side of the branch goes to the end block
5377 // directly and the path originates from the start block from the point of
5378 // view of the new PHI.
5379 BasicBlock *TT, *FT;
5380 if (TrueBlock == nullptr) {
5381 TT = EndBlock;
5382 FT = FalseBlock;
5383 TrueBlock = StartBlock;
5384 } else if (FalseBlock == nullptr) {
5385 TT = TrueBlock;
5386 FT = EndBlock;
5387 FalseBlock = StartBlock;
5388 } else {
5389 TT = TrueBlock;
5390 FT = FalseBlock;
5391 }
5392 IRBuilder<>(SI).CreateCondBr(SI->getCondition(), TT, FT, SI);
5393
5394 SmallPtrSet<const Instruction *, 2> INS;
5395 INS.insert(ASI.begin(), ASI.end());
5396 // Use reverse iterator because later select may use the value of the
5397 // earlier select, and we need to propagate value through earlier select
5398 // to get the PHI operand.
5399 for (auto It = ASI.rbegin(); It != ASI.rend(); ++It) {
5400 SelectInst *SI = *It;
5401 // The select itself is replaced with a PHI Node.
5402 PHINode *PN = PHINode::Create(SI->getType(), 2, "", &EndBlock->front());
5403 PN->takeName(SI);
5404 PN->addIncoming(getTrueOrFalseValue(SI, true, INS), TrueBlock);
5405 PN->addIncoming(getTrueOrFalseValue(SI, false, INS), FalseBlock);
5406
5407 SI->replaceAllUsesWith(PN);
5408 SI->eraseFromParent();
5409 INS.erase(SI);
5410 ++NumSelectsExpanded;
5411 }
5412
5413 // Instruct OptimizeBlock to skip to the next block.
5414 CurInstIterator = StartBlock->end();
5415 return true;
5416}
5417
5418static bool isBroadcastShuffle(ShuffleVectorInst *SVI) {
5419 SmallVector<int, 16> Mask(SVI->getShuffleMask());
5420 int SplatElem = -1;
5421 for (unsigned i = 0; i < Mask.size(); ++i) {
5422 if (SplatElem != -1 && Mask[i] != -1 && Mask[i] != SplatElem)
5423 return false;
5424 SplatElem = Mask[i];
5425 }
5426
5427 return true;
5428}
5429
5430/// Some targets have expensive vector shifts if the lanes aren't all the same
5431/// (e.g. x86 only introduced "vpsllvd" and friends with AVX2). In these cases
5432/// it's often worth sinking a shufflevector splat down to its use so that
5433/// codegen can spot all lanes are identical.
5434bool CodeGenPrepare::optimizeShuffleVectorInst(ShuffleVectorInst *SVI) {
5435 BasicBlock *DefBB = SVI->getParent();
5436
5437 // Only do this xform if variable vector shifts are particularly expensive.
5438 if (!TLI || !TLI->isVectorShiftByScalarCheap(SVI->getType()))
5439 return false;
5440
5441 // We only expect better codegen by sinking a shuffle if we can recognise a
5442 // constant splat.
5443 if (!isBroadcastShuffle(SVI))
5444 return false;
5445
5446 // InsertedShuffles - Only insert a shuffle in each block once.
5447 DenseMap<BasicBlock*, Instruction*> InsertedShuffles;
5448
5449 bool MadeChange = false;
5450 for (User *U : SVI->users()) {
5451 Instruction *UI = cast<Instruction>(U);
5452
5453 // Figure out which BB this ext is used in.
5454 BasicBlock *UserBB = UI->getParent();
5455 if (UserBB == DefBB) continue;
5456
5457 // For now only apply this when the splat is used by a shift instruction.
5458 if (!UI->isShift()) continue;
5459
5460 // Everything checks out, sink the shuffle if the user's block doesn't
5461 // already have a copy.
5462 Instruction *&InsertedShuffle = InsertedShuffles[UserBB];
5463
5464 if (!InsertedShuffle) {
5465 BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
5466 assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
(0) : __assert_fail ("InsertPt != UserBB->end()", "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5466, __extension__ __PRETTY_FUNCTION__))
;
5467 InsertedShuffle =
5468 new ShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
5469 SVI->getOperand(2), "", &*InsertPt);
5470 }
5471
5472 UI->replaceUsesOfWith(SVI, InsertedShuffle);
5473 MadeChange = true;
5474 }
5475
5476 // If we removed all uses, nuke the shuffle.
5477 if (SVI->use_empty()) {
5478 SVI->eraseFromParent();
5479 MadeChange = true;
5480 }
5481
5482 return MadeChange;
5483}
5484
5485bool CodeGenPrepare::optimizeSwitchInst(SwitchInst *SI) {
5486 if (!TLI || !DL)
5487 return false;
5488
5489 Value *Cond = SI->getCondition();
5490 Type *OldType = Cond->getType();
5491 LLVMContext &Context = Cond->getContext();
5492 MVT RegType = TLI->getRegisterType(Context, TLI->getValueType(*DL, OldType));
5493 unsigned RegWidth = RegType.getSizeInBits();
5494
5495 if (RegWidth <= cast<IntegerType>(OldType)->getBitWidth())
5496 return false;
5497
5498 // If the register width is greater than the type width, expand the condition
5499 // of the switch instruction and each case constant to the width of the
5500 // register. By widening the type of the switch condition, subsequent
5501 // comparisons (for case comparisons) will not need to be extended to the
5502 // preferred register width, so we will potentially eliminate N-1 extends,
5503 // where N is the number of cases in the switch.
5504 auto *NewType = Type::getIntNTy(Context, RegWidth);
5505
5506 // Zero-extend the switch condition and case constants unless the switch
5507 // condition is a function argument that is already being sign-extended.
5508 // In that case, we can avoid an unnecessary mask/extension by sign-extending
5509 // everything instead.
5510 Instruction::CastOps ExtType = Instruction::ZExt;
5511 if (auto *Arg = dyn_cast<Argument>(Cond))
5512 if (Arg->hasSExtAttr())
5513 ExtType = Instruction::SExt;
5514
5515 auto *ExtInst = CastInst::Create(ExtType, Cond, NewType);
5516 ExtInst->insertBefore(SI);
5517 SI->setCondition(ExtInst);
5518 for (auto Case : SI->cases()) {
5519 APInt NarrowConst = Case.getCaseValue()->getValue();
5520 APInt WideConst = (ExtType == Instruction::ZExt) ?
5521 NarrowConst.zext(RegWidth) : NarrowConst.sext(RegWidth);
5522 Case.setValue(ConstantInt::get(Context, WideConst));
5523 }
5524
5525 return true;
5526}
5527
5528
5529namespace {
5530
5531/// \brief Helper class to promote a scalar operation to a vector one.
5532/// This class is used to move downward extractelement transition.
5533/// E.g.,
5534/// a = vector_op <2 x i32>
5535/// b = extractelement <2 x i32> a, i32 0
5536/// c = scalar_op b
5537/// store c
5538///
5539/// =>
5540/// a = vector_op <2 x i32>
5541/// c = vector_op a (equivalent to scalar_op on the related lane)
5542/// * d = extractelement <2 x i32> c, i32 0
5543/// * store d
5544/// Assuming both extractelement and store can be combine, we get rid of the
5545/// transition.
5546class VectorPromoteHelper {
5547 /// DataLayout associated with the current module.
5548 const DataLayout &DL;
5549
5550 /// Used to perform some checks on the legality of vector operations.
5551 const TargetLowering &TLI;
5552
5553 /// Used to estimated the cost of the promoted chain.
5554 const TargetTransformInfo &TTI;
5555
5556 /// The transition being moved downwards.
5557 Instruction *Transition;
5558
5559 /// The sequence of instructions to be promoted.
5560 SmallVector<Instruction *, 4> InstsToBePromoted;
5561
5562 /// Cost of combining a store and an extract.
5563 unsigned StoreExtractCombineCost;
5564
5565 /// Instruction that will be combined with the transition.
5566 Instruction *CombineInst = nullptr;
5567
5568 /// \brief The instruction that represents the current end of the transition.
5569 /// Since we are faking the promotion until we reach the end of the chain
5570 /// of computation, we need a way to get the current end of the transition.
5571 Instruction *getEndOfTransition() const {
5572 if (InstsToBePromoted.empty())
5573 return Transition;
5574 return InstsToBePromoted.back();
5575 }
5576
5577 /// \brief Return the index of the original value in the transition.
5578 /// E.g., for "extractelement <2 x i32> c, i32 1" the original value,
5579 /// c, is at index 0.
5580 unsigned getTransitionOriginalValueIdx() const {
5581 assert(isa<ExtractElementInst>(Transition) &&(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5582, __extension__ __PRETTY_FUNCTION__))
5582 "Other kind of transitions are not supported yet")(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5582, __extension__ __PRETTY_FUNCTION__))
;
5583 return 0;
5584 }
5585
5586 /// \brief Return the index of the index in the transition.
5587 /// E.g., for "extractelement <2 x i32> c, i32 0" the index
5588 /// is at index 1.
5589 unsigned getTransitionIdx() const {
5590 assert(isa<ExtractElementInst>(Transition) &&(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5591, __extension__ __PRETTY_FUNCTION__))
5591 "Other kind of transitions are not supported yet")(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5591, __extension__ __PRETTY_FUNCTION__))
;
5592 return 1;
5593 }
5594
5595 /// \brief Get the type of the transition.
5596 /// This is the type of the original value.
5597 /// E.g., for "extractelement <2 x i32> c, i32 1" the type of the
5598 /// transition is <2 x i32>.
5599 Type *getTransitionType() const {
5600 return Transition->getOperand(getTransitionOriginalValueIdx())->getType();
5601 }
5602
5603 /// \brief Promote \p ToBePromoted by moving \p Def downward through.
5604 /// I.e., we have the following sequence:
5605 /// Def = Transition <ty1> a to <ty2>
5606 /// b = ToBePromoted <ty2> Def, ...
5607 /// =>
5608 /// b = ToBePromoted <ty1> a, ...
5609 /// Def = Transition <ty1> ToBePromoted to <ty2>
5610 void promoteImpl(Instruction *ToBePromoted);
5611
5612 /// \brief Check whether or not it is profitable to promote all the
5613 /// instructions enqueued to be promoted.
5614 bool isProfitableToPromote() {
5615 Value *ValIdx = Transition->getOperand(getTransitionOriginalValueIdx());
5616 unsigned Index = isa<ConstantInt>(ValIdx)
5617 ? cast<ConstantInt>(ValIdx)->getZExtValue()
5618 : -1;
5619 Type *PromotedType = getTransitionType();
5620
5621 StoreInst *ST = cast<StoreInst>(CombineInst);
5622 unsigned AS = ST->getPointerAddressSpace();
5623 unsigned Align = ST->getAlignment();
5624 // Check if this store is supported.
5625 if (!TLI.allowsMisalignedMemoryAccesses(
5626 TLI.getValueType(DL, ST->getValueOperand()->getType()), AS,
5627 Align)) {
5628 // If this is not supported, there is no way we can combine
5629 // the extract with the store.
5630 return false;
5631 }
5632
5633 // The scalar chain of computation has to pay for the transition
5634 // scalar to vector.
5635 // The vector chain has to account for the combining cost.
5636 uint64_t ScalarCost =
5637 TTI.getVectorInstrCost(Transition->getOpcode(), PromotedType, Index);
5638 uint64_t VectorCost = StoreExtractCombineCost;
5639 for (const auto &Inst : InstsToBePromoted) {
5640 // Compute the cost.
5641 // By construction, all instructions being promoted are arithmetic ones.
5642 // Moreover, one argument is a constant that can be viewed as a splat
5643 // constant.
5644 Value *Arg0 = Inst->getOperand(0);
5645 bool IsArg0Constant = isa<UndefValue>(Arg0) || isa<ConstantInt>(Arg0) ||
5646 isa<ConstantFP>(Arg0);
5647 TargetTransformInfo::OperandValueKind Arg0OVK =
5648 IsArg0Constant ? TargetTransformInfo::OK_UniformConstantValue
5649 : TargetTransformInfo::OK_AnyValue;
5650 TargetTransformInfo::OperandValueKind Arg1OVK =
5651 !IsArg0Constant ? TargetTransformInfo::OK_UniformConstantValue
5652 : TargetTransformInfo::OK_AnyValue;
5653 ScalarCost += TTI.getArithmeticInstrCost(
5654 Inst->getOpcode(), Inst->getType(), Arg0OVK, Arg1OVK);
5655 VectorCost += TTI.getArithmeticInstrCost(Inst->getOpcode(), PromotedType,
5656 Arg0OVK, Arg1OVK);
5657 }
5658 DEBUG(dbgs() << "Estimated cost of computation to be promoted:\nScalar: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Estimated cost of computation to be promoted:\nScalar: "
<< ScalarCost << "\nVector: " << VectorCost
<< '\n'; } } while (false)
5659 << ScalarCost << "\nVector: " << VectorCost << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Estimated cost of computation to be promoted:\nScalar: "
<< ScalarCost << "\nVector: " << VectorCost
<< '\n'; } } while (false)
;
5660 return ScalarCost > VectorCost;
5661 }
5662
5663 /// \brief Generate a constant vector with \p Val with the same
5664 /// number of elements as the transition.
5665 /// \p UseSplat defines whether or not \p Val should be replicated
5666 /// across the whole vector.
5667 /// In other words, if UseSplat == true, we generate <Val, Val, ..., Val>,
5668 /// otherwise we generate a vector with as many undef as possible:
5669 /// <undef, ..., undef, Val, undef, ..., undef> where \p Val is only
5670 /// used at the index of the extract.
5671 Value *getConstantVector(Constant *Val, bool UseSplat) const {
5672 unsigned ExtractIdx = std::numeric_limits<unsigned>::max();
5673 if (!UseSplat) {
5674 // If we cannot determine where the constant must be, we have to
5675 // use a splat constant.
5676 Value *ValExtractIdx = Transition->getOperand(getTransitionIdx());
5677 if (ConstantInt *CstVal = dyn_cast<ConstantInt>(ValExtractIdx))
5678 ExtractIdx = CstVal->getSExtValue();
5679 else
5680 UseSplat = true;
5681 }
5682
5683 unsigned End = getTransitionType()->getVectorNumElements();
5684 if (UseSplat)
5685 return ConstantVector::getSplat(End, Val);
5686
5687 SmallVector<Constant *, 4> ConstVec;
5688 UndefValue *UndefVal = UndefValue::get(Val->getType());
5689 for (unsigned Idx = 0; Idx != End; ++Idx) {
5690 if (Idx == ExtractIdx)
5691 ConstVec.push_back(Val);
5692 else
5693 ConstVec.push_back(UndefVal);
5694 }
5695 return ConstantVector::get(ConstVec);
5696 }
5697
5698 /// \brief Check if promoting to a vector type an operand at \p OperandIdx
5699 /// in \p Use can trigger undefined behavior.
5700 static bool canCauseUndefinedBehavior(const Instruction *Use,
5701 unsigned OperandIdx) {
5702 // This is not safe to introduce undef when the operand is on
5703 // the right hand side of a division-like instruction.
5704 if (OperandIdx != 1)
5705 return false;
5706 switch (Use->getOpcode()) {
5707 default:
5708 return false;
5709 case Instruction::SDiv:
5710 case Instruction::UDiv:
5711 case Instruction::SRem:
5712 case Instruction::URem:
5713 return true;
5714 case Instruction::FDiv:
5715 case Instruction::FRem:
5716 return !Use->hasNoNaNs();
5717 }
5718 llvm_unreachable(nullptr)::llvm::llvm_unreachable_internal(nullptr, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5718)
;
5719 }
5720
5721public:
5722 VectorPromoteHelper(const DataLayout &DL, const TargetLowering &TLI,
5723 const TargetTransformInfo &TTI, Instruction *Transition,
5724 unsigned CombineCost)
5725 : DL(DL), TLI(TLI), TTI(TTI), Transition(Transition),
5726 StoreExtractCombineCost(CombineCost) {
5727 assert(Transition && "Do not know how to promote null")(static_cast <bool> (Transition && "Do not know how to promote null"
) ? void (0) : __assert_fail ("Transition && \"Do not know how to promote null\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5727, __extension__ __PRETTY_FUNCTION__))
;
5728 }
5729
5730 /// \brief Check if we can promote \p ToBePromoted to \p Type.
5731 bool canPromote(const Instruction *ToBePromoted) const {
5732 // We could support CastInst too.
5733 return isa<BinaryOperator>(ToBePromoted);
5734 }
5735
5736 /// \brief Check if it is profitable to promote \p ToBePromoted
5737 /// by moving downward the transition through.
5738 bool shouldPromote(const Instruction *ToBePromoted) const {
5739 // Promote only if all the operands can be statically expanded.
5740 // Indeed, we do not want to introduce any new kind of transitions.
5741 for (const Use &U : ToBePromoted->operands()) {
5742 const Value *Val = U.get();
5743 if (Val == getEndOfTransition()) {
5744 // If the use is a division and the transition is on the rhs,
5745 // we cannot promote the operation, otherwise we may create a
5746 // division by zero.
5747 if (canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo()))
5748 return false;
5749 continue;
5750 }
5751 if (!isa<ConstantInt>(Val) && !isa<UndefValue>(Val) &&
5752 !isa<ConstantFP>(Val))
5753 return false;
5754 }
5755 // Check that the resulting operation is legal.
5756 int ISDOpcode = TLI.InstructionOpcodeToISD(ToBePromoted->getOpcode());
5757 if (!ISDOpcode)
5758 return false;
5759 return StressStoreExtract ||
5760 TLI.isOperationLegalOrCustom(
5761 ISDOpcode, TLI.getValueType(DL, getTransitionType(), true));
5762 }
5763
5764 /// \brief Check whether or not \p Use can be combined
5765 /// with the transition.
5766 /// I.e., is it possible to do Use(Transition) => AnotherUse?
5767 bool canCombine(const Instruction *Use) { return isa<StoreInst>(Use); }
5768
5769 /// \brief Record \p ToBePromoted as part of the chain to be promoted.
5770 void enqueueForPromotion(Instruction *ToBePromoted) {
5771 InstsToBePromoted.push_back(ToBePromoted);
5772 }
5773
5774 /// \brief Set the instruction that will be combined with the transition.
5775 void recordCombineInstruction(Instruction *ToBeCombined) {
5776 assert(canCombine(ToBeCombined) && "Unsupported instruction to combine")(static_cast <bool> (canCombine(ToBeCombined) &&
"Unsupported instruction to combine") ? void (0) : __assert_fail
("canCombine(ToBeCombined) && \"Unsupported instruction to combine\""
, "/build/llvm-toolchain-snapshot-7~svn326246/lib/CodeGen/CodeGenPrepare.cpp"
, 5776, __extension__ __PRETTY_FUNCTION__))
;
5777 CombineInst = ToBeCombined;
5778 }
5779
5780 /// \brief Promote all the instructions enqueued for promotion if it is
5781 /// is profitable.
5782 /// \return True if the promotion happened, false otherwise.
5783 bool promote() {