llvm-6502

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

History

Adam Nemet c76d187944 Revert "Reformat." This reverts commit r229651. I'd like to ultimately revert r229650 but this reformat stands in the way. I'll reformat the affected files once the the loop-access pass is fully committed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229889 91177308-0d34-0410-b5e6-96231b3b80d8		2015-02-19 19:14:34 +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	Revert "Reformat."	2015-02-19 19:14:34 +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))

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