llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-11-01 00:11:00 +00:00

History

Adam Nemet b7e0193c4d [LoopAccesses] Change LAA:getInfo to return a constant reference As expected, this required a few more const-correctness fixes. Based on Hal's feedback on D7684. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229899 91177308-0d34-0410-b5e6-96231b3b80d8		2015-02-19 19:15:21 +00:00
..
IPA	Analysis: Canonicalize access to function attributes, NFC	2015-02-14 00:12:15 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp	Introduce print-memderefs to test isDereferenceablePointer	2015-02-06 01:46:42 +00:00
AssumptionCache.cpp
BasicAliasAnalysis.cpp	[BasicAA] Try to disambiguate GEPs through arrays of structs into	2015-02-07 17:04:29 +00:00
BlockFrequencyInfo.cpp
BlockFrequencyInfoImpl.cpp
BranchProbabilityInfo.cpp
CaptureTracking.cpp
CFG.cpp
CFGPrinter.cpp
CFLAliasAnalysis.cpp	Fixed a bug where CFLAA would crash the compiler.	2015-02-12 03:07:07 +00:00
CGSCCPassManager.cpp
CMakeLists.txt	Use ADDITIONAL_HEADER_DIRS in all LLVM CMake projects.	2015-02-11 03:28:02 +00:00
CodeMetrics.cpp
ConstantFolding.cpp
CostModel.cpp
Delinearization.cpp
DependenceAnalysis.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InstCount.cpp
InstructionSimplify.cpp	InstCombine: cleanup redundant dyn_cast<> (NFC)	2015-02-13 07:38:04 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
JumpInstrTableInfo.cpp
LazyCallGraph.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp	Unify the two EH personality classification routines I wrote	2015-02-14 00:21:02 +00:00
Lint.cpp	[PM] Remove the old 'PassManager.h' header file at the top level of	2015-02-13 10:01:29 +00:00
LLVMBuild.txt
Loads.cpp
LoopAccessAnalysis.cpp	[LoopAccesses] Change LAA:getInfo to return a constant reference	2015-02-19 19:15:21 +00:00
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp	MemDepPrinter: cleanup a few loops (NFC)	2015-02-09 19:49:54 +00:00
MemDerefPrinter.cpp	MemDerefPrinter: Require DataLayoutPass for higher accuracy	2015-02-09 21:50:03 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Revert 229175	2015-02-15 19:07:31 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PHITransAddr.cpp
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Address post commit review on r229600.	2015-02-18 08:03:22 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
ScopedNoAliasAA.cpp
SparsePropagation.cpp
StratifiedSets.h
TargetLibraryInfo.cpp
TargetTransformInfo.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp	Correctly combine alias.scope metadata by a union instead of intersecting	2015-02-08 17:07:14 +00:00
ValueTracking.cpp	ValueTracking: Make isBytewiseValue simpler and more powerful at the same time.	2015-02-07 19:29:02 +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))

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