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llvm-mirror/lib/Analysis
Nikita Popov ba8e158b08 [ValueTracking] Use ConstantRange based overflow check for signed sub
This is D59450, but for signed sub. This case is not NFC, because
the overflow logic in ConstantRange is more powerful than the existing
check. This resolves the TODO in the function.

I've added two tests to show that this indeed catches more cases than
the previous logic, but the main correctness test coverage here is in
the existing ConstantRange unit tests.

Differential Revision: https://reviews.llvm.org/D59617

llvm-svn: 356685
2019-03-21 17:23:51 +00:00
..
AliasAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
AliasAnalysisEvaluator.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
AliasAnalysisSummary.cpp Move CFLGraph and the AA summary code over to the new CallBase 2019-02-11 09:25:41 +00:00
AliasAnalysisSummary.h Move CFLGraph and the AA summary code over to the new CallBase 2019-02-11 09:25:41 +00:00
AliasSetTracker.cpp [LICM/MSSA] Add promotion to scalars by building an AliasSetTracker with MemorySSA. 2019-02-06 20:25:17 +00:00
Analysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
AssumptionCache.cpp [CodeExtractor] Update function's assumption cache after extracting blocks from it 2019-02-08 06:55:18 +00:00
BasicAliasAnalysis.cpp [BasicAA] Use DenseMap::try_emplace after D59151. NFC 2019-03-21 08:47:40 +00:00
BlockFrequencyInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
BlockFrequencyInfoImpl.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
BranchProbabilityInfo.cpp [BPI] Look through bitcasts in calcZeroHeuristic 2019-02-15 11:50:21 +00:00
CallGraph.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CallGraphSCCPass.cpp Fix IR/Analysis layering issue with OptBisect 2019-02-28 04:00:55 +00:00
CallPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CaptureTracking.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CFG.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CFGPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CFLAndersAliasAnalysis.cpp [CFLAnders] Fix typo in comment; NFC 2019-03-08 19:28:55 +00:00
CFLGraph.h Move CFLGraph and the AA summary code over to the new CallBase 2019-02-11 09:25:41 +00:00
CFLSteensAliasAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGSCCPassManager.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CMakeLists.txt Move DomTreeUpdater from IR to Analysis 2019-02-06 02:52:52 +00:00
CmpInstAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CodeMetrics.cpp Remove CallSite from the CodeMetrics analysis, moving it to the new 2019-02-11 09:03:32 +00:00
ConstantFolding.cpp [CallSite removal] Migrate ConstantFolding APIs and implementation to 2019-02-11 07:51:44 +00:00
CostModel.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Delinearization.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
DemandedBits.cpp [DemandedBits] Remove some redundancy in the work list 2019-03-03 14:50:01 +00:00
DependenceAnalysis.cpp [DA][NewPM] Handle transitive dependencies in the new-pm version of DA 2019-02-03 12:25:41 +00:00
DivergenceAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
DominanceFrontier.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
DomPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
DomTreeUpdater.cpp [DTU] Refine the interface and logic of applyUpdates 2019-02-22 13:48:38 +00:00
EHPersonalities.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
GlobalsModRef.cpp [NFC] fix trivial typos in comments 2019-02-05 08:30:48 +00:00
GuardUtils.cpp [NFC] Add function to parse widenable conditional branches 2019-01-22 11:21:32 +00:00
IndirectCallPromotionAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
InlineCost.cpp Revert "[INLINER] allow inlining of address taken blocks" 2019-02-14 23:42:21 +00:00
InstCount.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
InstructionPrecedenceTracking.cpp Make widenable condition transparent for MemoryWriteTracking 2019-02-14 11:10:29 +00:00
InstructionSimplify.cpp [InstSimplify] SimplifyICmpInst - icmp eq/ne %X, undef -> undef 2019-03-19 14:08:23 +00:00
Interval.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
IntervalPartition.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
IteratedDominanceFrontier.cpp [IDF] Delete a redundant J-edge test 2019-03-07 11:42:59 +00:00
IVDescriptors.cpp Reland "Relax constraints for reduction vectorization" 2019-03-12 01:31:44 +00:00
IVUsers.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LazyBlockFrequencyInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LazyBranchProbabilityInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LazyCallGraph.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LazyValueInfo.cpp [NFC] fix trivial typos in comments 2019-02-05 08:30:48 +00:00
LegacyDivergenceAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Lint.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LLVMBuild.txt Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Loads.cpp [Analysis] Fix isSafeToLoadUnconditionally handling of volatile. 2019-01-24 21:31:13 +00:00
LoopAccessAnalysis.cpp [NFC] fix trivial typos in comments 2019-02-05 08:30:48 +00:00
LoopAnalysisManager.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LoopInfo.cpp Refactor setAlreadyUnrolled() and setAlreadyVectorized(). 2019-02-11 19:45:44 +00:00
LoopPass.cpp Fix IR/Analysis layering issue with OptBisect 2019-02-28 04:00:55 +00:00
LoopUnrollAnalyzer.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MemDepPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MemDerefPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MemoryBuiltins.cpp Add a 'dynamic' parameter to the objectsize intrinsic 2019-01-30 20:34:35 +00:00
MemoryDependenceAnalysis.cpp [NFC] Fix typos: preceeding -> preceding 2019-02-23 01:28:32 +00:00
MemoryLocation.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MemorySSA.cpp [MSSA] Delete move ctor; remove dynamic never-moved verification 2019-03-21 03:11:34 +00:00
MemorySSAUpdater.cpp [MemorySSA] Make insertDef insert corresponding phi nodes. 2019-02-27 22:20:22 +00:00
ModuleDebugInfoPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ModuleSummaryAnalysis.cpp [ThinLTO] Restructure AliasSummary to contain ValueInfo of Aliasee 2019-03-15 15:11:38 +00:00
MustExecute.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ObjCARCAliasAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ObjCARCAnalysisUtils.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ObjCARCInstKind.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
OptimizationRemarkEmitter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
OrderedBasicBlock.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
OrderedInstructions.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PHITransAddr.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PhiValues.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PostDominators.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ProfileSummaryInfo.cpp [PGO] Context sensitive PGO (part 2) 2019-02-28 19:55:07 +00:00
PtrUseVisitor.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
README.txt
RegionInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegionPass.cpp [RegionPass] Fix forgotten "!". 2019-03-08 21:03:06 +00:00
RegionPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ScalarEvolution.cpp [SCEV] Use depth limit for trunc analysis 2019-03-12 18:28:05 +00:00
ScalarEvolutionAliasAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ScalarEvolutionExpander.cpp [SCEV] Guard movement of insertion point for loop-invariants 2019-03-18 18:52:35 +00:00
ScalarEvolutionNormalization.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ScopedNoAliasAA.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
StackSafetyAnalysis.cpp Hide two unused debugging methods, NFCI. 2019-03-01 17:15:21 +00:00
StratifiedSets.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SyncDependenceAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SyntheticCountsUtils.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TargetLibraryInfo.cpp [SelectionDAG] Allow the user to specify a memeq function. 2019-03-08 09:07:45 +00:00
TargetTransformInfo.cpp [TTI] Enable analysis of clib functions in getIntrinsicCosts. NFCI. 2019-03-12 09:48:02 +00:00
Trace.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TypeBasedAliasAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TypeMetadataUtils.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ValueLattice.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ValueLatticeUtils.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ValueTracking.cpp [ValueTracking] Use ConstantRange based overflow check for signed sub 2019-03-21 17:23:51 +00:00
VectorUtils.cpp [Vectorizer] Add vectorization support for fixed smul/umul intrinsics 2019-02-25 15:42:02 +00:00

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))

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