llvm-6502/lib/Analysis
Dan Gohman 615da1a9bc Teach BasicAA to return PartialAlias in cases where both pointers
are pointing to the same object, one pointer is accessing the entire
object, and the other is access has a non-zero size. This prevents
TBAA from kicking in and saying NoAlias in such cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123775 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-18 21:16:06 +00:00
..
IPA Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment, 2011-01-03 23:51:43 +00:00
AliasAnalysis.cpp Stub out a new updating interface to AliasAnalysis, allowing stateful analyses to be informed when 2011-01-03 21:38:41 +00:00
AliasAnalysisCounter.cpp Teach AliasAnalysisCounter about PartialAlias. 2010-12-10 19:53:05 +00:00
AliasAnalysisEvaluator.cpp Teach AliasAnalysisEvaluator about PartialAlias. 2010-12-10 19:52:40 +00:00
AliasDebugger.cpp Extend the AliasAnalysis::pointsToConstantMemory interface to allow it 2010-11-08 16:45:26 +00:00
AliasSetTracker.cpp Update this code to handle PartialAlias as MayAlias. 2010-12-10 19:40:47 +00:00
Analysis.cpp Move DominanceFrontier from VMCore to Analysis. 2011-01-18 06:06:27 +00:00
BasicAliasAnalysis.cpp Teach BasicAA to return PartialAlias in cases where both pointers 2011-01-18 21:16:06 +00:00
CaptureTracking.cpp VAArg doesn't capture its operand. 2010-11-09 20:09:35 +00:00
CFGPrinter.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
CMakeLists.txt Move DominanceFrontier from VMCore to Analysis. 2011-01-18 06:06:27 +00:00
ConstantFolding.cpp fix PR8983, a broken assertion. 2011-01-16 03:43:53 +00:00
DbgInfoPrinter.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
DebugInfo.cpp Add support to create class type. 2010-12-08 20:18:20 +00:00
DIBuilder.cpp Use type's file info while describing inheritance relationship. 2010-12-08 21:46:37 +00:00
DominanceFrontier.cpp Move DominanceFrontier from VMCore to Analysis. 2011-01-18 06:06:27 +00:00
DomPrinter.cpp split dom frontier handling stuff out to its own DominanceFrontier header, 2011-01-02 22:09:33 +00:00
InlineCost.cpp Now using a variant of the existing inlining heuristics to decide whether to create a given specialization of a function in PartialSpecialization. If the total performance bonus across all callsites passing the same constant exceeds the specialization cost, we create the specialization. 2010-10-09 22:06:36 +00:00
InstCount.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
InstructionSimplify.cpp For completeness, generalize the (X + Y) - Y -> X transform and add X - (X + 1) -> -1. 2011-01-18 11:50:19 +00:00
Interval.cpp Change Pass::print to take a raw ostream instead of std::ostream, 2009-08-23 06:03:38 +00:00
IntervalPartition.cpp Now with fewer extraneous semicolons! 2010-10-07 22:25:06 +00:00
IVUsers.cpp split dom frontier handling stuff out to its own DominanceFrontier header, 2011-01-02 22:09:33 +00:00
LazyValueInfo.cpp Teach LazyValueInfo that allocas aren't NULL. Over all of llvm-test, this saves 2011-01-15 09:16:12 +00:00
LibCallAliasAnalysis.cpp Now with fewer extraneous semicolons! 2010-10-07 22:25:06 +00:00
LibCallSemantics.cpp Thread const correctness through a bunch of AliasAnalysis interfaces and 2010-08-03 21:48:53 +00:00
Lint.cpp Move Value::getUnderlyingObject to be a standalone 2010-12-15 20:02:24 +00:00
LiveValues.cpp split dom frontier handling stuff out to its own DominanceFrontier header, 2011-01-02 22:09:33 +00:00
Loads.cpp Move Value::getUnderlyingObject to be a standalone 2010-12-15 20:02:24 +00:00
LoopDependenceAnalysis.cpp split dom frontier handling stuff out to its own DominanceFrontier header, 2011-01-02 22:09:33 +00:00
LoopInfo.cpp Fix typo pointed out by Trevor Harmon. 2010-11-13 12:16:27 +00:00
LoopPass.cpp zap dead code. 2010-09-04 18:12:00 +00:00
Makefile make -fno-rtti the default unless a directory builds with REQUIRES_RTTI. 2010-01-24 20:43:08 +00:00
MemDepPrinter.cpp Add helper functions for computing the Location of load, store, 2010-11-11 21:50:19 +00:00
MemoryBuiltins.cpp minor enhancement to llvm::isFreeCall API: return CallInst; no functional change 2010-06-23 21:51:12 +00:00
MemoryDependenceAnalysis.cpp Revert r123207: "Turn on memdep's verifyRemoved() in an attempt to smoke out the cause of our gcc bootstrap miscompare." 2011-01-11 04:05:39 +00:00
ModuleDebugInfoPrinter.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
NoAliasAnalysis.cpp Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment, 2011-01-03 23:51:43 +00:00
PHITransAddr.cpp split dom frontier handling stuff out to its own DominanceFrontier header, 2011-01-02 22:09:33 +00:00
PostDominators.cpp split dom frontier handling stuff out to its own DominanceFrontier header, 2011-01-02 22:09:33 +00:00
ProfileEstimatorPass.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
ProfileInfo.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
ProfileInfoLoader.cpp Reapplied r81355 with the problems fixed. 2009-09-16 11:35:50 +00:00
ProfileInfoLoaderPass.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
ProfileVerifierPass.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
README.txt When checking whether the special handling for an addrec increment which 2010-04-26 21:46:36 +00:00
RegionInfo.cpp Add single entry / single exit accessors. 2011-01-13 23:18:04 +00:00
RegionPass.cpp Remove useless dynamic_cast<>(). 2010-12-12 21:58:28 +00:00
RegionPrinter.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
ScalarEvolution.cpp some comment improvements. 2011-01-11 17:11:59 +00:00
ScalarEvolutionAliasAnalysis.cpp Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which 2010-10-19 17:21:58 +00:00
ScalarEvolutionExpander.cpp Introduce memoization for ScalarEvolution dominates and properlyDominates 2010-11-18 00:34:22 +00:00
ScalarEvolutionNormalization.cpp Disable the asserts that check that normalization is perfectly 2010-09-03 22:12:56 +00:00
SparsePropagation.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 22:28:01 +00:00
Trace.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 22:35:10 +00:00
TypeBasedAliasAnalysis.cpp Update a comment. 2010-12-16 02:55:10 +00:00
ValueTracking.cpp fix an off-by-one bug that caused a crash analyzing 2011-01-04 18:19:15 +00:00

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))

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