llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-09-30 19:55:11 +00:00

History

Michael Gottesman e2058ff5bd Added BlockFrequencyInfo::view for displaying the block frequency propagation graph via graphviz. This is useful for debugging issues in the BlockFrequency implementation since one can easily visualize where probability mass and other errors occur in the propagation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194654 91177308-0d34-0410-b5e6-96231b3b80d8		2013-11-14 02:27:46 +00:00
..
IPA	Move the old pass manager infrastructure into a legacy namespace and	2013-11-09 12:26:54 +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	Revert r193251 : Use address-taken to disambiguate global variable and indirect memops.	2013-10-27 03:08:44 +00:00
BlockFrequencyInfo.cpp	Added BlockFrequencyInfo::view for displaying the block frequency propagation graph via graphviz.	2013-11-14 02:27:46 +00:00
BranchProbabilityInfo.cpp	Consider (x == -1) unlikely in BranchProbabilityInfo	2013-11-01 10:58:22 +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	Fix another constant folding address space place I missed.	2013-11-04 20:46:52 +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
MemoryBuiltins.cpp
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
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	add more comments around the delinearization of arrays	2013-11-13 22:37:58 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Fix SCEVExpander: don't try to expand quadratic recurrences outside a loop.	2013-10-25 21:35:56 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
TargetTransformInfo.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp

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))

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