llvm-6502/lib/Analysis
Dan Gohman c1f1efdd1a Update a comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121727 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 22:53:18 +00:00
..
IPA
AliasAnalysis.cpp
AliasAnalysisCounter.cpp Teach AliasAnalysisCounter about PartialAlias. 2010-12-10 19:53:05 +00:00
AliasAnalysisEvaluator.cpp Teach AliasAnalysisEvaluator about PartialAlias. 2010-12-10 19:52:40 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp Update this code to handle PartialAlias as MayAlias. 2010-12-10 19:40:47 +00:00
Analysis.cpp
BasicAliasAnalysis.cpp Reapply r121520, PartialAlias implementation for BasicAA, now that 2010-12-13 22:50:24 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and 2010-12-07 08:25:19 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp Add support to create class type. 2010-12-08 20:18:20 +00:00
DIBuilder.cpp Use type's file info while describing inheritance relationship. 2010-12-08 21:46:37 +00:00
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp Take the first step towards making LVI non-recursive: get rid of the LVIQuery abstraction. 2010-12-09 06:14:58 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp Update a comment. 2010-12-13 22:53:18 +00:00
LiveValues.cpp
Loads.cpp
LoopDependenceAnalysis.cpp Minimally update this code to handle PartialAlias. 2010-12-10 20:14:49 +00:00
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp Update memdep to handle PartialAlias as MayAlias. 2010-12-13 22:47:57 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PHITransAddr.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp Remove useless dynamic_cast<>(). 2010-12-12 21:58:28 +00:00
RegionPrinter.cpp
ScalarEvolution.cpp PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and 2010-12-07 08:25:19 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and 2010-12-07 08:25:19 +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))

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