llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-11-05 13:09:10 +00:00

History

Michael Gottesman b68ca3e9c5 [block-freq] Teach branch probability how to return the edge weight in between a BasicBlock and one of its successors. IMHO At some point BasicBlock should be refactored along the lines of MachineBasicBlock so that successors/weights are actually embedded within the block. Now is not that time though. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197303 91177308-0d34-0410-b5e6-96231b3b80d8		2013-12-14 02:24:25 +00:00
..
IPA	[inliner] Fix PR18206 by preventing inlining functions that call setjmp	2013-12-13 08:00:01 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp	delinearization of arrays	2013-11-12 22:47:20 +00:00
BasicAliasAnalysis.cpp	Use correct size for address space in BasicAA.	2013-11-16 00:36:43 +00:00
BlockFrequencyInfo.cpp	[block-freq] Update BlockFrequencyInfo/MachineBlockFrequencyInfo to use the new print methods.	2013-12-14 00:25:42 +00:00
BranchProbabilityInfo.cpp	[block-freq] Teach branch probability how to return the edge weight in between a BasicBlock and one of its successors.	2013-12-14 02:24:25 +00:00
CaptureTracking.cpp
CFG.cpp
CFGPrinter.cpp
CMakeLists.txt	delinearization of arrays	2013-11-12 22:47:20 +00:00
CodeMetrics.cpp
ConstantFolding.cpp	Add addrspacecast instruction.	2013-11-15 01:34:59 +00:00
CostModel.cpp
Delinearization.cpp	add more comments around the delinearization of arrays	2013-11-13 22:37:58 +00:00
DependenceAnalysis.cpp	add more comments around the delinearization of arrays	2013-11-13 22:37:58 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Use size function instead of manually calculating it.	2013-11-10 03:18:50 +00:00
LLVMBuild.txt
Loads.cpp
LoopInfo.cpp	Simplify code. No functionality change.	2013-11-13 20:18:38 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Fix typo.	2013-12-04 23:55:09 +00:00
MemoryBuiltins.cpp	Teach MemoryBuiltins about address spaces	2013-12-14 00:27:48 +00:00
MemoryDependenceAnalysis.cpp	Fixing a heisenbug where the memory dependence analysis behaves differently	2013-11-14 01:10:52 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PHITransAddr.cpp	Correct word hyphenations	2013-12-05 05:44:44 +00:00
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Annotate APInt methods where it's not clear whether they are in place with warn_unused_result.	2013-11-16 16:25:41 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Don't #include heavy Dominators.h file in LoopInfo.h. This change reduces	2013-12-07 21:20:17 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
TargetTransformInfo.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	Don't speculate loads under ThreadSanitizer	2013-11-21 07:29:28 +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))

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