llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-19 17:33:29 +00:00

History

Dan Gohman 3fcfc9fafa Re-introduce the MaxLookup limit to BasicAliasAnalysis' pointsToConstantMemory code to guard against possible compile time slowdowns. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118440 91177308-0d34-0410-b5e6-96231b3b80d8		2010-11-08 20:26:19 +00:00
..
IPA
AliasAnalysis.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
AliasAnalysisCounter.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp	Re-introduce the MaxLookup limit to BasicAliasAnalysis'	2010-11-08 20:26:19 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	Introduce DIBuilder. It is intended to be a front-end friendly interface to emit debuggging information entries in LLVM IR.	2010-11-04 15:01:38 +00:00
ConstantFolding.cpp
DbgInfoPrinter.cpp
DebugInfo.cpp	Fix DIType verifier. The element 3 is DIFile now.	2010-11-02 20:41:13 +00:00
DIBuilder.cpp	Use arrays instead of constant-sized SmallVectors.	2010-11-04 18:45:27 +00:00
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp	Add simplification of floating point comparisons with the result	2010-11-07 16:46:25 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LiveValues.cpp
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Memdep says that an instruction clobbers itself	2010-10-20 22:37:41 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Teach memdep to use pointsToConstantMemory to determine that loads	2010-10-29 01:14:04 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
PHITransAddr.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp	Make some symbols static, move classes into anonymous namespaces.	2010-10-22 17:35:07 +00:00
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Make ScalarEvolution::forgetLoop forget all contained loops too, because	2010-10-29 20:16:10 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp	Implement getModRefBehavior for TypeBasedAliasAnalysis.	2010-11-08 17:10:22 +00:00
ValueTracking.cpp

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))

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