llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-28 04:33:05 +00:00

History

Eli Friedman 7781ae5be5 Fix code to match comment. Fixes PR11340, a regression from r143209. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144121 91177308-0d34-0410-b5e6-96231b3b80d8		2011-11-08 21:08:02 +00:00
..
IPA	build: Add initial cut at LLVMBuild.txt files.	2011-11-03 18:53:17 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp	Fix the API usage in loop probability heuristics. It was incorrectly	2011-10-25 09:47:41 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp
DbgInfoPrinter.cpp
DebugInfo.cpp
DIBuilder.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp	A FIXME about block addresses and indirectbr.	2011-10-20 04:05:33 +00:00
InstCount.cpp
InstructionSimplify.cpp	Fix code to match comment. Fixes PR11340, a regression from r143209.	2011-11-08 21:08:02 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt	build: Add initial cut at LLVMBuild.txt files.	2011-11-03 18:53:17 +00:00
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Restore commits 142790 and 142843 - they weren't breaking the build	2011-10-25 12:28:52 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	A shift of a power of two is a power of two or zero.	2011-10-28 18:30:05 +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))

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