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llvm-mirror/lib/Analysis
Whitney Tsang e5741d7263 Title: [LOOPINFO] Extend Loop object to add utilities to get the loop
bounds, step, and loop induction variable.

Summary: This PR extends the loop object with more utilities to get loop
bounds, step, and loop induction variable. There already exists passes
which try to obtain the loop induction variable in their own pass, e.g.
loop interchange. It would be useful to have a common area to get these
information.

/// Example:
/// for (int i = lb; i < ub; i+=step)
///   <loop body>
/// --- pseudo LLVMIR ---
/// beforeloop:
///   guardcmp = (lb < ub)
///   if (guardcmp) goto preheader; else goto afterloop
/// preheader:
/// loop:
///   i1 = phi[{lb, preheader}, {i2, latch}]
///   <loop body>
///   i2 = i1 + step
/// latch:
///   cmp = (i2 < ub)
///   if (cmp) goto loop
/// exit:
/// afterloop:
///
/// getBounds
///   getInitialIVValue      --> lb
///   getStepInst            --> i2 = i1 + step
///   getStepValue           --> step
///   getFinalIVValue        --> ub
///   getCanonicalPredicate  --> '<'
///   getDirection           --> Increasing
/// getInductionVariable          --> i1
/// getAuxiliaryInductionVariable --> {i1}
/// isCanonical                   --> false

Reviewers: kbarton, hfinkel, dmgreen, Meinersbur, jdoerfert, syzaara,
fhahn
Reviewed By: kbarton
Subscribers: tvvikram, bmahjour, etiotto, fhahn, jsji, hiraditya,
llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D60565

llvm-svn: 362609
2019-06-05 14:34:12 +00:00
..
AliasAnalysis.cpp [AliasAnalysis/NewPassManager] Invalidate AAManager less often. 2019-04-30 22:15:47 +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 Add an optional list of blocks to avoid when looking for a path in isPotentiallyReachable. 2019-04-02 01:05:48 +00:00
BlockFrequencyInfo.cpp Add optional arg to profile count getters to filter 2019-04-24 19:51:16 +00:00
BlockFrequencyInfoImpl.cpp Add optional arg to profile count getters to filter 2019-04-24 19:51:16 +00:00
BranchProbabilityInfo.cpp [BPI] Look through bitcasts in calcZeroHeuristic 2019-02-15 11:50:21 +00:00
CallGraph.cpp [CallSite removal] Move the legacy PM, call graph, and some inliner 2019-04-19 05:59:42 +00:00
CallGraphSCCPass.cpp [CallSite removal] Move the legacy PM, call graph, and some inliner 2019-04-19 05:59:42 +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 Add an optional list of blocks to avoid when looking for a path in isPotentiallyReachable. 2019-04-02 01:05:48 +00:00
CFG.cpp An unreachable block may have a route to a reachable block, don't fast-path return that it can't. 2019-04-04 23:09:40 +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 [AliasAnalysis] Second prototype to cache BasicAA / anyAA state. 2019-03-22 17:22:19 +00:00
CFLGraph.h CFLAA: reflow comments; NFC 2019-06-03 19:56:22 +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 [NewPM] Fix a nasty bug with analysis invalidation in the new PM. 2019-03-28 00:51:36 +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 Add FNeg IR constant folding support 2019-05-05 16:07:09 +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 Add "const" in GetUnderlyingObjects. NFC 2019-04-24 06:55:50 +00:00
GuardUtils.cpp [WideableCond] Fix a nasty bug in detection of "explicit guards" 2019-04-02 16:51:43 +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 [InlineCost] Don't add the soft float function call cost for the fneg idiom, fsub -0.0, %x 2019-06-01 19:40:07 +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 [InstructionSimplify] Add missing implementation of llvm::SimplifyUnOp. NFC 2019-05-31 08:10:23 +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 Save the induction binary operator in IVDescriptors for non FP induction variables. 2019-05-14 13:26:36 +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 [LCG] Add aliased functions as LCG roots 2019-04-05 18:51:08 +00:00
LazyValueInfo.cpp Introduce Value::stripPointerCastsSameRepresentation 2019-06-04 20:21:46 +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 [Lint] Permit aliasing noalias readonly arguments 2019-04-23 23:43:47 +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 Add "const" in GetUnderlyingObjects. NFC 2019-04-24 06:55:50 +00:00
LoopAnalysisManager.cpp [MemorySSA] LCSSA preserves MemorySSA. 2019-04-23 20:59:44 +00:00
LoopInfo.cpp Title: [LOOPINFO] Extend Loop object to add utilities to get the loop 2019-06-05 14:34:12 +00:00
LoopPass.cpp ftime-trace: Trace loop passes 2019-05-31 10:14:04 +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 Fix a hang when lowering __builtin_dynamic_object_size 2019-04-10 23:42:11 +00:00
MemoryDependenceAnalysis.cpp [MemDepAnalysis] Allow caller to pass in an OrderedBasicBlock. 2019-03-28 19:17:31 +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 [MemorySSA] Check that block is reachable when adding phis. 2019-05-02 23:41:58 +00:00
MemorySSAUpdater.cpp [MemorySSA] Teach LoopSimplify to preserve MemorySSA. 2019-05-08 17:05:36 +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] Auto-hide prevailing linkonce_odr only when all copies eligible 2019-05-10 20:08:24 +00:00
MustExecute.cpp [MustExecute] Improve MustExecute to correctly handle loop nest 2019-05-27 13:57:28 +00:00
ObjCARCAliasAnalysis.cpp [AliasAnalysis] Second prototype to cache BasicAA / anyAA state. 2019-03-22 17:22:19 +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 Recommit "[DSE] Preserve basic block ordering using OrderedBasicBlock." 2019-03-29 14:10:24 +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 Add optional arg to profile count getters to filter 2019-04-24 19:51:16 +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 [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +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] Add explicit representations of umin/smin 2019-05-07 15:28:47 +00:00
ScalarEvolutionAliasAnalysis.cpp [AliasAnalysis] Second prototype to cache BasicAA / anyAA state. 2019-03-22 17:22:19 +00:00
ScalarEvolutionExpander.cpp [SCEV] Suppress hoisting insertion point of binops when unsafe 2019-05-08 18:50:07 +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 [AliasAnalysis] Second prototype to cache BasicAA / anyAA state. 2019-03-22 17:22:19 +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 [SDA] Bug fix: Use IPD outside the loop as divergence bound 2019-04-18 16:17:35 +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 Initial support for IBM MASS vector library 2019-06-05 01:31:43 +00:00
TargetTransformInfo.cpp [CostModel] Add really basic support for being able to query the cost of the FNeg instruction. 2019-05-28 04:09:18 +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 [AliasAnalysis] Second prototype to cache BasicAA / anyAA state. 2019-03-22 17:22:19 +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][ConstantRange] Distinguish low/high always overflow 2019-05-28 18:08:31 +00:00
VectorUtils.cpp Consolidate existing utilities for interpreting vector predicate maskes [NFC] 2019-04-25 02:30:17 +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))

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