llvm-project/llvm/lib/Analysis
Benjamin Kramer 557b601b08 [BasicAliasAnalysis] Simplify expression, no functional change.
(-1) - x + 1 is the same as -x.

llvm-svn: 251185
2015-10-24 11:38:01 +00:00
..
AliasAnalysis.cpp [AA] Enhance the new AliasAnalysis infrastructure with an optional 2015-10-21 12:15:19 +00:00
AliasAnalysisEvaluator.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
AliasSetTracker.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
Analysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
AssumptionCache.cpp [PM] Actually add the new pass manager support for the assumption cache. 2015-01-22 21:53:09 +00:00
BasicAliasAnalysis.cpp [BasicAliasAnalysis] Simplify expression, no functional change. 2015-10-24 11:38:01 +00:00
BlockFrequencyInfo.cpp Recommit r250345, it was reverted in r250366 to investigate a bot failure. 2015-10-15 14:59:40 +00:00
BlockFrequencyInfoImpl.cpp Recommit r250345, it was reverted in r250366 to investigate a bot failure. 2015-10-15 14:59:40 +00:00
BranchProbabilityInfo.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
CFG.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
CFGPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
CFLAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
CGSCCPassManager.cpp [PM] Remove the defunt CGSCC-specific debug flag. 2015-01-13 22:45:13 +00:00
CMakeLists.txt [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
CallGraph.cpp [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
CallGraphSCCPass.cpp [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
CallPrinter.cpp [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
CaptureTracking.cpp [IR] Give catchret an optional 'return value' operand 2015-08-15 02:46:08 +00:00
CodeMetrics.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
ConstantFolding.cpp Enable constant propagation for more math functions 2015-08-27 19:56:57 +00:00
CostModel.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
Delinearization.cpp SCEV: Allow simple AddRec * Parameter products in delinearization 2015-10-12 08:02:00 +00:00
DemandedBits.cpp Compute demanded bits for icmp instructions 2015-10-08 12:40:06 +00:00
DependenceAnalysis.cpp [SCEV] Introduce ScalarEvolution::getOne and getZero. 2015-09-23 01:59:04 +00:00
DivergenceAnalysis.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
DomPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
DominanceFrontier.cpp Templatify DominanceFrontier. 2014-07-12 21:59:52 +00:00
GlobalsModRef.cpp [GlobalsAA] Loosen an overly conservative bailout 2015-10-22 13:44:26 +00:00
IVUsers.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
InlineCost.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
InstCount.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
InstructionSimplify.cpp Extract out getConstantRangeFromMetadata; NFC 2015-10-24 05:37:35 +00:00
Interval.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
IntervalPartition.cpp
IteratedDominanceFrontier.cpp Move IDF Calculation to a separate file, expose an interface to it. 2015-04-21 19:13:02 +00:00
LLVMBuild.txt [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
LazyCallGraph.cpp Revert r225854: [PM] Move the LazyCallGraph printing functionality to 2015-01-14 00:27:45 +00:00
LazyValueInfo.cpp [LazyValueInfo] Report nonnull range for nonnull pointers 2015-09-18 13:01:48 +00:00
LibCallSemantics.cpp [WinEH] Recognize CoreCLR personality function 2015-10-06 20:28:16 +00:00
Lint.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
Loads.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
LoopAccessAnalysis.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
LoopInfo.cpp [IR] Add token types 2015-08-14 05:09:07 +00:00
LoopPass.cpp LoopPass: Remove redoLoop, it isn't used. NFC 2015-10-22 21:31:34 +00:00
Makefile [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
MemDepPrinter.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
MemDerefPrinter.cpp Take alignment into account in isSafeToSpeculativelyExecute and isSafeToLoadUnconditionally. 2015-08-17 15:54:26 +00:00
MemoryBuiltins.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
MemoryDependenceAnalysis.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
MemoryLocation.cpp [PM/AA] Split the location computation out of getArgLocation so the 2015-06-17 07:12:40 +00:00
ModuleDebugInfoPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
ObjCARCAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
ObjCARCAnalysisUtils.cpp [ARC] Pull the ObjC ARC components that really serve the role of 2015-08-20 08:06:03 +00:00
ObjCARCInstKind.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
OrderedBasicBlock.cpp [CaptureTracker] Provide an ordered basic block to PointerMayBeCapturedBefore 2015-07-31 14:31:35 +00:00
PHITransAddr.cpp [PHITransAddr] Don't assume that instruction operands are translatable 2015-08-09 15:43:02 +00:00
PostDominators.cpp
PtrUseVisitor.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
README.txt
RegionInfo.cpp [RegionInfo] Add debug-time region viewer functions 2015-08-10 13:21:59 +00:00
RegionPass.cpp Change range-based for-loops to be -Wrange-loop-analysis clean. 2015-04-15 01:21:15 +00:00
RegionPrinter.cpp [RegionInfo] Add debug-time region viewer functions 2015-08-10 13:21:59 +00:00
ScalarEvolution.cpp Extract out getConstantRangeFromMetadata; NFC 2015-10-24 05:37:35 +00:00
ScalarEvolutionAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
ScalarEvolutionExpander.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
ScalarEvolutionNormalization.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
ScopedNoAliasAA.cpp Fix Clang-tidy modernize-use-nullptr warnings in source directories and generated files; other minor cleanups. 2015-10-06 23:24:35 +00:00
SparsePropagation.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
StratifiedSets.h Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
TargetLibraryInfo.cpp Populate list of vectorizable functions for Accelerate library. 2015-05-07 17:11:51 +00:00
TargetTransformInfo.cpp Removed parameter "Consecutive" from isLegalMaskedLoad() / isLegalMaskedStore(). 2015-10-19 07:43:38 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
ValueTracking.cpp Extract out getConstantRangeFromMetadata; NFC 2015-10-24 05:37:35 +00:00
VectorUtils.cpp [LoopVectorize] Shrink integer operations into the smallest type possible 2015-10-12 12:34:45 +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))

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