llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-21 00:32:23 +00:00

History

Chris Lattner f1cadf2899 use isNullValue() to simplify code, add an assert. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122977 91177308-0d34-0410-b5e6-96231b3b80d8		2011-01-06 22:24:29 +00:00
..
IPA	Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,	2011-01-03 23:51:43 +00:00
AliasAnalysis.cpp	Stub out a new updating interface to AliasAnalysis, allowing stateful analyses to be informed when	2011-01-03 21:38:41 +00:00
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	fix rdar://8813415 - a miscompilation of 164.gzip that loop-idiom	2011-01-03 21:03:33 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp	use isNullValue() to simplify code, add an assert.	2011-01-06 22:24:29 +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	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp	Revert commit 122654 at the request of Chris, who reckons that instsimplify	2011-01-01 20:08:02 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
LazyValueInfo.cpp	Reorder, rename, and document some members to make this easier to follow.	2011-01-05 23:26:22 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Move Value::getUnderlyingObject to be a standalone	2010-12-15 20:02:24 +00:00
LiveValues.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
Loads.cpp	Move Value::getUnderlyingObject to be a standalone	2010-12-15 20:02:24 +00:00
LoopDependenceAnalysis.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Change all self assignments X=X to (void)X, so that we can turn on a	2010-12-23 00:58:24 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp	Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,	2011-01-03 23:51:43 +00:00
PHITransAddr.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
PostDominators.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
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	Update a comment.	2010-12-16 02:55:10 +00:00
ValueTracking.cpp	fix an off-by-one bug that caused a crash analyzing	2011-01-04 18:19:15 +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))

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