llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-13 20:32:21 +00:00

History

Wei Mi d5892380e1 Create a wrapper pass for BlockFrequencyInfo. This is useful when we want to do block frequency analysis conditionally (e.g. only in PGO mode) but don't want to add one more pass dependence. Patch by congh. Approved by dexonsmith. Differential Revision: http://reviews.llvm.org/D11196 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242248 91177308-0d34-0410-b5e6-96231b3b80d8		2015-07-14 23:40:50 +00:00
..
IPA	[PM/AA] Reformat GlobalsModRef so that subsequent patches I make here	2015-07-14 08:42:39 +00:00
AliasAnalysis.cpp	[PM/AA] Completely remove the AliasAnalysis::copyValue interface.	2015-07-11 04:39:00 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp	[PM/AA] Completely remove the AliasAnalysis::copyValue interface.	2015-07-11 04:39:00 +00:00
AliasSetTracker.cpp	[PM/AA] Completely remove the AliasAnalysis::copyValue interface.	2015-07-11 04:39:00 +00:00
Analysis.cpp	Create a wrapper pass for BlockFrequencyInfo.	2015-07-14 23:40:50 +00:00
AssumptionCache.cpp
BasicAliasAnalysis.cpp	Revert r241981 "Revert "Revert r236894 "[BasicAA] Fix zext & sext handling"""	2015-07-13 13:50:55 +00:00
BlockFrequencyInfo.cpp	Create a wrapper pass for BlockFrequencyInfo.	2015-07-14 23:40:50 +00:00
BlockFrequencyInfoImpl.cpp
BranchProbabilityInfo.cpp
CaptureTracking.cpp
CFG.cpp
CFGPrinter.cpp
CFLAliasAnalysis.cpp
CGSCCPassManager.cpp
CMakeLists.txt
CodeMetrics.cpp
ConstantFolding.cpp	Allow constfolding of llvm.sin.* and llvm.cos.* intrinsics	2015-07-08 03:55:47 +00:00
CostModel.cpp
Delinearization.cpp	Move delinearization from SCEVAddRecExpr to ScalarEvolution	2015-06-29 14:42:48 +00:00
DependenceAnalysis.cpp	Move delinearization from SCEVAddRecExpr to ScalarEvolution	2015-06-29 14:42:48 +00:00
DivergenceAnalysis.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InstCount.cpp
InstructionSimplify.cpp	[InstSimplify] Teach InstSimplify how to simplify extractelement	2015-07-13 01:15:53 +00:00
Interval.cpp
IntervalPartition.cpp
IteratedDominanceFrontier.cpp
IVUsers.cpp	[LSR] don't attempt to promote ephemeral values to indvars	2015-07-13 03:28:53 +00:00
LazyCallGraph.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt
Loads.cpp
LoopAccessAnalysis.cpp	[LAA] Introduce RuntimePointerChecking::PointerInfo, NFC	2015-07-14 22:32:50 +00:00
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemDerefPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
MemoryLocation.cpp
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp	[PM/AA] Completely remove the AliasAnalysis::copyValue interface.	2015-07-11 04:39:00 +00:00
PHITransAddr.cpp
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Move delinearization from SCEVAddRecExpr to ScalarEvolution	2015-06-29 14:42:48 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
ScopedNoAliasAA.cpp
SparsePropagation.cpp
StratifiedSets.h
TargetLibraryInfo.cpp
TargetTransformInfo.cpp	Make TargetTransformInfo keeping a reference to the Module DataLayout	2015-07-09 02:08:42 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	IR: Do not consider available_externally linkage to be linker-weak.	2015-07-05 20:52:35 +00:00
VectorUtils.cpp	[InstSimplify] Teach InstSimplify how to simplify extractelement	2015-07-13 01:15:53 +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))

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