llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-10-05 22:59:16 +00:00

History

Arnold Schwaighofer 4fc6484ee2 Cost model: Add check for reverse shuffles to CostModel analysis Check for reverse shuffles in the CostModel analysis pass and query TargetTransform info accordingly. This allows us we can write test cases for reverse shuffles. radar://13171406 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174932 91177308-0d34-0410-b5e6-96231b3b80d8		2013-02-12 02:40:37 +00:00
..
IPA	Begin fleshing out an interface in TTI for modelling the costs of	2013-01-22 11:26:02 +00:00
AliasAnalysis.cpp	Move isKnownNonNull out of AliasAnalysis.h and into ValueTracking.cpp since	2013-01-31 02:40:59 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	Sink InlineCost.cpp into IPA -- it is now officially an interprocedural	2013-01-21 12:09:41 +00:00
CodeMetrics.cpp	Begin fleshing out an interface in TTI for modelling the costs of	2013-01-22 11:26:02 +00:00
ConstantFolding.cpp	Conditionalize constant folding of math intrinsics on the availability of an implementation on the host. This is a little bit unfortunate, but until someone decides to implement a full libm for APFloat, we don't have a better way to get this functionality.	2013-02-07 00:21:34 +00:00
CostModel.cpp	Cost model: Add check for reverse shuffles to CostModel analysis	2013-02-12 02:40:37 +00:00
DbgInfoPrinter.cpp
DependenceAnalysis.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InstCount.cpp
InstructionSimplify.cpp	Identify and simplify idempotent intrinsics. Test case included.	2013-02-07 19:26:05 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp	Move isKnownNonNull out of AliasAnalysis.h and into ValueTracking.cpp since	2013-01-31 02:40:59 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Change GetPointerBaseWithConstantOffset's DataLayout argument from a	2013-01-31 02:00:45 +00:00
LLVMBuild.txt
Loads.cpp	Change GetPointerBaseWithConstantOffset's DataLayout argument from a	2013-01-31 02:00:45 +00:00
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp	Reverting r171325 & r172363. This was causing a mis-compile on the self-hosted LTO build bots.	2013-01-17 21:28:46 +00:00
MemoryDependenceAnalysis.cpp	Change GetPointerBaseWithConstantOffset's DataLayout argument from a	2013-01-31 02:00:45 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp
PostDominators.cpp
ProfileDataLoader.cpp
ProfileDataLoaderPass.cpp	Revert "Add LLVMContext::emitWarning methods and use them. <rdar://problem/12867368>"	2013-02-08 21:48:29 +00:00
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp	Revert "Add LLVMContext::emitWarning methods and use them. <rdar://problem/12867368>"	2013-02-08 21:48:29 +00:00
ProfileVerifierPass.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	SCEVExpander fix. RAUW needs to update the InsertedExpressions cache.	2013-01-14 21:00:37 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
TargetTransformInfo.cpp	ARM cost model: Address computation in vector mem ops not free	2013-02-08 14:50:48 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	Move isKnownNonNull out of AliasAnalysis.h and into ValueTracking.cpp since	2013-01-31 02:40:59 +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))

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