llvm-project/llvm/lib/Analysis
Teresa Johnson f24136f17a [WPD] Fix incorrect devirtualization after indirect call promotion
Summary:
Add a dominance check to ensure that the possible devirtualizable
call is actually dominated by the type test/checked load intrinsic being
analyzed. With PGO, after indirect call promotion is performed during
the compile step, followed by inlining, we may have a type test in the
promoted and inlined sequence that allows an indirect call in that
sequence to be devirtualized. That indirect call (inserted by inlining
after promotion) will share the same vtable pointer as the fallback
indirect call that cannot be devirtualized.

Before this patch the code was incorrectly devirtualizing the fallback
indirect call.

See the new test and the example described there for more details.

Reviewers: pcc, vitalybuka

Subscribers: mehdi_amini, Prazek, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D52514

llvm-svn: 343226
2018-09-27 14:55:32 +00:00
..
AliasAnalysis.cpp [AA] Remove a needless variable [NFC] 2018-08-22 19:50:45 +00:00
AliasAnalysisEvaluator.cpp [MSSA] Print more optimization information 2018-06-14 19:55:53 +00:00
AliasAnalysisSummary.cpp
AliasAnalysisSummary.h Revert r332657: "[AA] cfl-anders-aa with field sensitivity" 2018-05-17 21:56:39 +00:00
AliasSetTracker.cpp [AST] Visit memtransfer arguments in order 2018-09-10 16:00:27 +00:00
Analysis.cpp [NFC] Rename the DivergenceAnalysis to LegacyDivergenceAnalysis 2018-08-30 14:21:36 +00:00
AssumptionCache.cpp [Analysis, Transforms] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC). 2017-09-01 21:37:29 +00:00
BasicAliasAnalysis.cpp [BasicAA] Don't assume tail calls with byval don't alias allocas 2018-08-14 01:24:35 +00:00
BlockFrequencyInfo.cpp Revert r320104: infinite loop profiling bug fix 2017-12-08 19:38:07 +00:00
BlockFrequencyInfoImpl.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-27 02:13:45 +00:00
BranchProbabilityInfo.cpp [BPI] Remove unnecessary std::list 2018-06-15 21:06:43 +00:00
CFG.cpp
CFGPrinter.cpp Remove trailing space 2018-07-30 19:41:25 +00:00
CFLAndersAliasAnalysis.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-27 02:13:45 +00:00
CFLGraph.h [IR] Replace `isa<TerminatorInst>` with `isTerminator()`. 2018-08-26 09:51:22 +00:00
CFLSteensAliasAnalysis.cpp Rename DEBUG macro to LLVM_DEBUG. 2018-05-14 12:53:11 +00:00
CGSCCPassManager.cpp [New PM] Introducing PassInstrumentation framework 2018-09-20 17:08:45 +00:00
CMakeLists.txt Break LoopUtils into an Analysis file. 2018-09-12 01:59:43 +00:00
CallGraph.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-27 02:13:45 +00:00
CallGraphSCCPass.cpp [New PM][PassInstrumentation] IR printing support for New Pass Manager 2018-09-24 16:08:15 +00:00
CallPrinter.cpp Revert "Extend CFGPrinter and CallPrinter with Heat Colors" 2018-06-29 17:48:58 +00:00
CaptureTracking.cpp Fix aliasing of launder.invariant.group 2018-05-23 09:16:44 +00:00
CmpInstAnalysis.cpp [InstCombine][InstSimplify] Teach decomposeBitTestICmp to look through truncate instructions 2017-09-01 21:27:34 +00:00
CodeMetrics.cpp Rename DEBUG macro to LLVM_DEBUG. 2018-05-14 12:53:11 +00:00
ConstantFolding.cpp Prevent Constant Folding From Optimizing inrange GEP 2018-09-11 01:53:36 +00:00
CostModel.cpp Remove redundant includes from lib/Analysis. 2017-12-13 21:30:41 +00:00
Delinearization.cpp [NFC] Consolidate six getPointerOperand() utility functions into one place 2018-03-09 21:05:58 +00:00
DemandedBits.cpp [IR] Replace `isa<TerminatorInst>` with `isTerminator()`. 2018-08-26 09:51:22 +00:00
DependenceAnalysis.cpp [DA] Delinearise AddRecs if we can prove they don't wrap 2018-06-25 15:13:26 +00:00
DomPrinter.cpp Revert "Extend CFGPrinter and CallPrinter with Heat Colors" 2018-06-29 17:48:58 +00:00
DominanceFrontier.cpp IWYU for llvm-config.h in llvm, additions. 2018-04-30 14:59:11 +00:00
EHPersonalities.cpp [WebAssembly] Add Wasm personality and isScopedEHPersonality() 2018-05-17 20:52:03 +00:00
GlobalsModRef.cpp Remove trailing space 2018-07-30 19:41:25 +00:00
GuardUtils.cpp Re-enable "[NFC] Unify guards detection" 2018-08-30 03:39:16 +00:00
IVDescriptors.cpp Remove unused include from IVDescriptors.cpp. 2018-09-12 07:22:46 +00:00
IVUsers.cpp Rename DEBUG macro to LLVM_DEBUG. 2018-05-14 12:53:11 +00:00
IndirectCallPromotionAnalysis.cpp Rename DEBUG macro to LLVM_DEBUG. 2018-05-14 12:53:11 +00:00
InlineCost.cpp [inline Cost] Don't mark functions accessing varargs as non-inlinable 2018-09-20 18:39:34 +00:00
InstCount.cpp [Analysis] RemoveTotalMemInst counting in InstCount to avoid reading back other Statistic variables 2017-07-18 02:41:12 +00:00
InstructionPrecedenceTracking.cpp [NFC] Rename variable 2018-09-11 05:10:01 +00:00
InstructionSimplify.cpp [IR] Replace `isa<TerminatorInst>` with `isTerminator()`. 2018-08-26 09:51:22 +00:00
Interval.cpp [Analysis] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC). 2017-07-24 23:16:33 +00:00
IntervalPartition.cpp [Analysis] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC). 2017-07-24 23:16:33 +00:00
IteratedDominanceFrontier.cpp [IDF] Teach Iterated Dominance Frontier to use a snapshot CFG based on a GraphDiff. 2018-08-17 17:39:15 +00:00
LLVMBuild.txt
LazyBlockFrequencyInfo.cpp Require DominatorTree when requiring/preserving LoopInfo in the old pass manager 2018-05-17 09:05:40 +00:00
LazyBranchProbabilityInfo.cpp Require DominatorTree when requiring/preserving LoopInfo in the old pass manager 2018-05-17 09:05:40 +00:00
LazyCallGraph.cpp [STLExtras] Add size() for ranges, and remove distance() 2018-05-16 23:20:42 +00:00
LazyValueInfo.cpp Remove trailing space 2018-07-30 19:41:25 +00:00
LegacyDivergenceAnalysis.cpp [NFC] Rename the DivergenceAnalysis to LegacyDivergenceAnalysis 2018-08-30 14:21:36 +00:00
Lint.cpp Remove \brief commands from doxygen comments. 2018-05-01 15:54:18 +00:00
Loads.cpp Fix aliasing of launder.invariant.group 2018-05-23 09:16:44 +00:00
LoopAccessAnalysis.cpp [LV][LAA] Vectorize loop invariant values stored into loop invariant address 2018-09-25 20:57:20 +00:00
LoopAnalysisManager.cpp [LoopPassManager] MemorySSA should be preserved when enabled. 2018-09-06 20:54:24 +00:00
LoopInfo.cpp [New PM][PassInstrumentation] IR printing support for New Pass Manager 2018-09-24 16:08:15 +00:00
LoopPass.cpp Output per-function size-info remarks 2018-09-06 21:19:54 +00:00
LoopUnrollAnalyzer.cpp Remove \brief commands from doxygen comments. 2018-05-01 15:54:18 +00:00
MemDepPrinter.cpp Remove trailing space 2018-07-30 19:41:25 +00:00
MemDerefPrinter.cpp Remove redundant includes from lib/Analysis. 2017-12-13 21:30:41 +00:00
MemoryBuiltins.cpp Reverting r340807. 2018-08-30 18:37:18 +00:00
MemoryDependenceAnalysis.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-27 02:13:45 +00:00
MemoryLocation.cpp [AST] Generalize argument specific aliasing 2018-09-07 21:36:11 +00:00
MemorySSA.cpp API to update MemorySSA for cloned blocks and added CFG edges. 2018-09-10 20:13:01 +00:00
MemorySSAUpdater.cpp [MemorySSAUpdater] Avoid creating self-referencing MemoryDefs 2018-09-11 14:29:59 +00:00
ModuleDebugInfoPrinter.cpp Remove redundant includes from lib/Analysis. 2017-12-13 21:30:41 +00:00
ModuleSummaryAnalysis.cpp [WPD] Fix incorrect devirtualization after indirect call promotion 2018-09-27 14:55:32 +00:00
MustExecute.cpp [NFC] Factor out predecessors collection into a separate method 2018-08-21 07:15:06 +00:00
ObjCARCAliasAnalysis.cpp [ModRefInfo] Make enum ModRefInfo an enum class [NFC]. 2017-12-07 22:41:34 +00:00
ObjCARCAnalysisUtils.cpp Remove \brief commands from doxygen comments. 2018-05-01 15:54:18 +00:00
ObjCARCInstKind.cpp [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label. 2018-05-09 02:40:45 +00:00
OptimizationRemarkEmitter.cpp Remove redundant includes from lib/Analysis. 2017-12-13 21:30:41 +00:00
OrderedBasicBlock.cpp [NFC] Sanitizing asserts for OrderedBasicBlock 2018-09-11 08:46:19 +00:00
OrderedInstructions.cpp [NFC] Move OrderedInstructions and InstructionPrecedenceTracking to Analysis 2018-08-30 04:49:03 +00:00
PHITransAddr.cpp IWYU for llvm-config.h in llvm, additions. 2018-04-30 14:59:11 +00:00
PhiValues.cpp [PhiValues] Use callback value handles to invalidate deleted values 2018-08-24 15:48:30 +00:00
PostDominators.cpp [Dominators] Add PDT constructor from Function 2018-05-23 17:29:21 +00:00
ProfileSummaryInfo.cpp [SampleFDO] Fix a bug in getOrCompHotCountThreshold/getOrCompColdCountThreshold 2018-08-07 18:13:10 +00:00
PtrUseVisitor.cpp [Analysis] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC). 2017-08-18 23:51:26 +00:00
README.txt
RegionInfo.cpp Test commit, fix a minor typo. 2018-07-22 20:04:42 +00:00
RegionPass.cpp [NFC][PassTiming] factor out generic PassTimingInfo 2018-08-28 21:06:51 +00:00
RegionPrinter.cpp Revert "Extend CFGPrinter and CallPrinter with Heat Colors" 2018-06-29 17:48:58 +00:00
ScalarEvolution.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-27 02:13:45 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-27 02:13:45 +00:00
ScalarEvolutionNormalization.cpp
ScopedNoAliasAA.cpp [ModRefInfo] Make enum ModRefInfo an enum class [NFC]. 2017-12-07 22:41:34 +00:00
StratifiedSets.h Remove \brief commands from doxygen comments. 2018-05-01 15:54:18 +00:00
SyntheticCountsUtils.cpp Remove CallGraphTraits and use equivalent methods in GraphTraits 2018-02-01 19:40:35 +00:00
TargetLibraryInfo.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-27 02:13:45 +00:00
TargetTransformInfo.cpp Remove trailing space 2018-07-30 19:41:25 +00:00
Trace.cpp IWYU for llvm-config.h in llvm, additions. 2018-04-30 14:59:11 +00:00
TypeBasedAliasAnalysis.cpp Fix more spelling mistakes in comments of LLVM Analysis passes 2018-03-02 18:57:02 +00:00
TypeMetadataUtils.cpp [WPD] Fix incorrect devirtualization after indirect call promotion 2018-09-27 14:55:32 +00:00
ValueLattice.cpp [LVI] Move LVILatticeVal class to separate header file (NFC). 2017-09-28 11:09:22 +00:00
ValueLatticeUtils.cpp [IPSCCP] Move common functions to ValueLatticeUtils (NFC) 2017-10-13 17:53:44 +00:00
ValueTracking.cpp Merge clang's isRepeatedBytePattern with LLVM's isBytewiseValue 2018-09-21 05:17:42 +00:00
VectorUtils.cpp [Analysis] add comment to generalize finding a scalar op from vector; NFC 2018-09-24 17:18:32 +00:00

README.txt

Analysis Opportunities:

//===---------------------------------------------------------------------===//

In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
ScalarEvolution expression for %r is this:

  {1,+,3,+,2}<loop>

Outside the loop, this could be evaluated simply as (%n * %n), however
ScalarEvolution currently evaluates it as

  (-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))

In addition to being much more complicated, it involves i65 arithmetic,
which is very inefficient when expanded into code.

//===---------------------------------------------------------------------===//

In formatValue in test/CodeGen/X86/lsr-delayed-fold.ll,

ScalarEvolution is forming this expression:

((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32)))

This could be folded to

(-1 * (trunc i64 undef to i32))

//===---------------------------------------------------------------------===//