llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-26 21:32:10 +00:00

History

Owen Anderson 2ab36d3502 Begin adding static dependence information to passes, which will allow us to perform initialization without static constructors AND without explicit initialization by the client. For the moment, passes are required to initialize both their (potential) dependencies and any passes they preserve. I hope to be able to relax the latter requirement in the future. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116334 91177308-0d34-0410-b5e6-96231b3b80d8		2010-10-12 19:48:12 +00:00
..
IPA	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
Analysis.cpp
BasicAliasAnalysis.cpp
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp
DbgInfoPrinter.cpp	Now with fewer extraneous semicolons!	2010-10-07 22:25:06 +00:00
DebugInfo.cpp
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
LiveValues.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
Loads.cpp
LoopDependenceAnalysis.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
LoopInfo.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
ModuleDebugInfoPrinter.cpp
PHITransAddr.cpp
PostDominators.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
ProfileEstimatorPass.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
README.txt
RegionInfo.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
RegionPrinter.cpp
ScalarEvolution.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
ScalarEvolutionAliasAnalysis.cpp	Begin adding static dependence information to passes, which will allow us to	2010-10-12 19:48:12 +00:00
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))

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