llvm/Analysis at a9b8338bfa126de7ad6d57ca417b39d5c6a979ff - llvm

RPCS3/llvm

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History

Duncan Sands 3472766f9e Convert some tab stops into spaces. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108130 91177308-0d34-0410-b5e6-96231b3b80d8		2010-07-12 08:16:59 +00:00
..
IPA	cache result of operator*	2010-07-09 16:22:36 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp	Minore code simplification.	2010-07-07 14:30:04 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp	Add parentheses around an \|\| to correct the logic. Also silences a GCC warning	2010-07-12 06:47:05 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Reverting r107918 and r107919. Radar 8063111.	2010-07-08 23:25:39 +00:00
DomPrinter.cpp	Convert some tab stops into spaces.	2010-07-12 08:16:59 +00:00
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LiveValues.cpp
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	cache result of operator*	2010-07-09 14:28:41 +00:00
LoopPass.cpp
Makefile
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
ModuleDebugInfoPrinter.cpp
PHITransAddr.cpp
PointerTracking.cpp
PostDominators.cpp	cache result of operator*	2010-07-09 15:52:36 +00:00
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
ScalarEvolution.cpp
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	remove useless cast and fix typos in comment	2010-07-09 16:42:04 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.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))

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