llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-11-07 12:07:17 +00:00

History

Dan Gohman 28680d33ee Make this comment more precise. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91722 91177308-0d34-0410-b5e6-96231b3b80d8		2009-12-18 23:18:03 +00:00
..
IPA
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp
DbgInfoPrinter.cpp	Fix GetConstantStringInfo to not look into MDString (it works on	2009-12-15 19:34:20 +00:00
DebugInfo.cpp	Add support to emit debug info for C++ namespaces.	2009-12-15 19:16:48 +00:00
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Add Loop contains utility methods for testing whether a loop	2009-12-18 01:24:09 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
LiveValues.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Add Loop contains utility methods for testing whether a loop	2009-12-18 01:24:09 +00:00
LoopPass.cpp
Makefile
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
PHITransAddr.cpp
PointerTracking.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
ScalarEvolution.cpp	Make this comment more precise.	2009-12-18 23:18:03 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
SparsePropagation.cpp
Trace.cpp
ValueTracking.cpp	Fix GetConstantStringInfo to not look into MDString (it works on	2009-12-15 19:34:20 +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.

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