llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-09-16 18:59:20 +00:00

History

Jakub Staszak 7cc2b07437 Introduce MachineBranchProbabilityInfo class, which has similar API to BranchProbabilityInfo (expect setEdgeWeight which is not available here). Branch Weights are kept in MachineBasicBlocks. To turn off this analysis set -use-mbpi=false. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133184 91177308-0d34-0410-b5e6-96231b3b80d8		2011-06-16 20:22:37 +00:00
..
IPA	Teach the CallGraph to ignore calls to intrinsics.	2011-06-09 19:46:27 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp	New BranchProbabilityInfo analysis. Patch by Jakub Staszak!	2011-06-04 01:16:30 +00:00
BasicAliasAnalysis.cpp	Initialize BasicAA's AliasCache to set it to use fewer buckets by	2011-06-10 22:30:30 +00:00
BranchProbabilityInfo.cpp	Introduce MachineBranchProbabilityInfo class, which has similar API to	2011-06-16 20:22:37 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	New BranchProbabilityInfo analysis. Patch by Jakub Staszak!	2011-06-04 01:16:30 +00:00
ConstantFolding.cpp
DbgInfoPrinter.cpp
DebugInfo.cpp
DIBuilder.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
Loads.cpp	Test commit.	2011-06-03 17:15:37 +00:00
LoopDependenceAnalysis.cpp
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Add "unknown" results for memdep, which mean "I don't know whether a dependence for the given instruction exists in the given block". This cleans up all the existing hacks in memdep which represent this concept by returning clobber with various unrelated instructions.	2011-06-15 00:47:34 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Add a limit to the number of instructions memdep will scan in a single block. This prevents (at least in some cases) O(N^2) runtime in passes like DSE.	2011-06-15 23:59:25 +00:00
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
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.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))

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