llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-01-01 00:33:09 +00:00

History

Nick Lewycky 69bfdf5a24 Clean up some of LVI: * mergeIn now uses constant folding for constants that are provably not-equal. * sink some sanity checks from the get() methods into the mark() methods, to ensure that we never have a constant/notconstant ConstantInt * some textual cleanups, whitespace changes, removing "else" after return, that sort of thing. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121877 91177308-0d34-0410-b5e6-96231b3b80d8		2010-12-15 18:57:18 +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
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	Move Sub simplifications and additional Add simplifications out of	2010-12-15 14:07:39 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp	Clean up some of LVI:	2010-12-15 18:57:18 +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	zap dead code.	2010-09-04 18:12:00 +00:00
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
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
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))

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