llvm-6502

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

History

Michael Zolotukhin 4a0593ccd3 PR17473: Don't normalize an expression during postinc transformation unless it's invertible. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203719 91177308-0d34-0410-b5e6-96231b3b80d8		2014-03-12 21:31:05 +00:00
..
IPA	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
AliasAnalysis.cpp	IR: add a second ordering operand to cmpxhg for failure	2014-03-11 10:48:52 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp
CaptureTracking.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
CFG.cpp
CFGPrinter.cpp
CMakeLists.txt
CodeMetrics.cpp
ConstantFolding.cpp
CostModel.cpp
Delinearization.cpp
DependenceAnalysis.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InstCount.cpp
InstructionSimplify.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	PR17473:	2014-03-12 21:31:05 +00:00
LazyCallGraph.cpp	[LCG] Ran clang-format over this too and it pointed out some fixes.	2014-03-10 02:14:14 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt
Loads.cpp
LoopInfo.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
MemoryDependenceAnalysis.cpp
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PHITransAddr.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
PostDominators.cpp
PtrUseVisitor.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +00:00
TargetTransformInfo.cpp	[TTI] There is actually no realistic way to pop TTI implementations off	2014-03-10 02:45:14 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	[C++11] Add range based accessors for the Use-Def chain of a Value.	2014-03-09 03:16:01 +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))

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