llvm-mirror

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History

Dan Gohman d9d4889ccc Constant-fold GEP-of-GEP into a single GEP. llvm-svn: 98178		2010-03-10 19:31:51 +00:00
..
IPA	Update CMake build.	2010-03-01 19:42:47 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp	Constant-fold GEP-of-GEP into a single GEP.	2010-03-10 19:31:51 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Start using DIFile. See updated SourceLevelDebugging.html for more information.	2010-03-09 00:44:10 +00:00
DomPrinter.cpp
InlineCost.cpp	Try to keep the cached inliner costs around for a bit longer for big functions.	2010-03-09 23:02:17 +00:00
InstCount.cpp
InstructionSimplify.cpp	fix incorrect folding of icmp with undef, PR6481.	2010-03-03 19:46:03 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Spelling fixes.	2010-03-01 17:49:51 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
LiveValues.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Make isLCSSA ignore uses in blocks not reachable from the entry block,	2010-03-09 01:53:33 +00:00
LoopPass.cpp
Makefile
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
PHITransAddr.cpp
PointerTracking.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
ScalarEvolution.cpp	Avoid analyzing instructions in blocks not reachable from the entry block.	2010-03-09 23:46:50 +00:00
ScalarEvolutionAliasAnalysis.cpp	Add a comment.	2010-03-01 17:56:04 +00:00
ScalarEvolutionExpander.cpp	Another place where debug info affected codegen.	2010-03-09 01:08:11 +00:00
SparsePropagation.cpp
Trace.cpp
ValueTracking.cpp	Move GetStringLength and helper from SimplifyLibCalls to ValueTracking.	2010-03-05 06:58:57 +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.

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