llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-15 04:30:12 +00:00

History

Jay Foad 40f8f6264d PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method trunc(), to be const and to return a new value instead of modifying the object in place. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121120 91177308-0d34-0410-b5e6-96231b3b80d8		2010-12-07 08:25:19 +00:00
..
IPA
AliasAnalysis.cpp	getLocationForDest should work for memset as well.	2010-11-30 01:48:20 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp	PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and	2010-12-07 08:25:19 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp	PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and	2010-12-07 08:25:19 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Also inore '()' while creating mdnode name from ObjC symbol name.	2010-12-03 23:40:45 +00:00
DIBuilder.cpp
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp	Add some dead stores to pacify my least favorite GCC warning: may be	2010-11-29 01:41:13 +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
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	strength reduce this.	2010-11-30 01:56:13 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PHITransAddr.cpp	Strip trailing whitespace.	2010-11-18 17:06:31 +00:00
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
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
ValueTracking.cpp	PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and	2010-12-07 08:25:19 +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))

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