llvm-6502/lib/Analysis
Preston Briggs 72a2c0622a Corrects a problem where we reply exclusively of GEPs to drive
analysis.  Better is to look for cases with useful GEPs and use them
when possible.  When a pair of useful GEPs is not available, use the
raw SCEVs directly. This approach supports better analysis of pointer
dereferencing.

In parallel, all the test cases are updated appropriately.
Cases where we have a store to *B++ can now be analyzed!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168474 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-21 23:50:04 +00:00
..
IPA Add doInitialization and doFinalization methods to ModulePass's, to allow them to be re-initialized and reused on multiple Module's. 2012-11-15 00:14:15 +00:00
AliasAnalysis.cpp Use the attribute enums to query if a parameter has an attribute. 2012-10-09 21:38:14 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp Move TargetData to DataLayout. 2012-10-08 16:38:25 +00:00
Analysis.cpp Add a cost model analysis that allows us to estimate the cost of IR-level instructions. 2012-11-02 21:48:17 +00:00
BasicAliasAnalysis.cpp Phi speculation improvement for BasicAA 2012-11-17 02:33:15 +00:00
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle 2012-08-24 18:14:27 +00:00
CaptureTracking.cpp Give CaptureTracker::shouldExplore a base implementation. Most users want to do 2012-10-08 22:12:48 +00:00
CFGPrinter.cpp
CMakeLists.txt Add a cost model analysis that allows us to estimate the cost of IR-level instructions. 2012-11-02 21:48:17 +00:00
CodeMetrics.cpp Revert the majority of the next patch in the address space series: 2012-11-01 09:14:31 +00:00
ConstantFolding.cpp llvm/ConstantFolding.cpp: Make ReadDataFromGlobal() and FoldReinterpretLoadFromConstPtr() Big-endian-aware. 2012-11-08 20:34:25 +00:00
CostModel.cpp CostModel: add support for Vector Insert and Extract. 2012-11-02 22:31:56 +00:00
DbgInfoPrinter.cpp Move lib/Analysis/DebugInfo.cpp to lib/VMCore/DebugInfo.cpp and 2012-06-28 00:05:13 +00:00
DependenceAnalysis.cpp Corrects a problem where we reply exclusively of GEPs to drive 2012-11-21 23:50:04 +00:00
DominanceFrontier.cpp Release build: guard dump functions with 2012-09-12 05:06:18 +00:00
DomPrinter.cpp
InlineCost.cpp Clean up handling of always-inline functions in the inliner. 2012-11-19 07:04:35 +00:00
InstCount.cpp
InstructionSimplify.cpp Make this easier to understand, as suggested by Chandler. 2012-11-16 20:53:08 +00:00
Interval.cpp Revert 'Fix a typo 'iff' => 'if''. iff is an abreviation of if and only if. See: http://en.wikipedia.org/wiki/If_and_only_if Commit 164767 2012-09-27 10:14:43 +00:00
IntervalPartition.cpp
IVUsers.cpp Move TargetData to DataLayout. 2012-10-08 16:38:25 +00:00
LazyValueInfo.cpp Hoist out some work done inside a loop doing a linear scan over all 2012-10-26 04:43:47 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp Revert the series of commits starting with r166578 which introduced the 2012-11-01 08:07:29 +00:00
LLVMBuild.txt
Loads.cpp Move TargetData to DataLayout. 2012-10-08 16:38:25 +00:00
LoopInfo.cpp Release build: guard dump functions with 2012-09-12 05:06:18 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp Revert the series of commits starting with r166578 which introduced the 2012-11-01 08:07:29 +00:00
MemoryDependenceAnalysis.cpp Ignore unreachable blocks when doing memory dependence analysis on non-local 2012-10-23 18:37:11 +00:00
ModuleDebugInfoPrinter.cpp Move lib/Analysis/DebugInfo.cpp to lib/VMCore/DebugInfo.cpp and 2012-06-28 00:05:13 +00:00
NoAliasAnalysis.cpp Move TargetData to DataLayout. 2012-10-08 16:38:25 +00:00
PathNumbering.cpp Move llvm/Support/TypeBuilder.h -> llvm/TypeBuilder.h. This completes 2012-07-15 23:45:24 +00:00
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp Release build: guard dump functions with 2012-09-12 05:06:18 +00:00
PostDominators.cpp
ProfileDataLoader.cpp Remove code to saturate profile counts. 2012-10-29 17:27:39 +00:00
ProfileDataLoaderPass.cpp Cleanups due to feedback. No functionality change. Patch by Alistair. 2012-08-31 05:18:31 +00:00
ProfileEstimatorPass.cpp Fix floating-point divide by zero, in a case where the value was not going to be used anyway. 2012-08-24 00:31:45 +00:00
ProfileInfo.cpp Profile: set branch weight metadata with data generated from profiling. 2012-08-28 22:21:25 +00:00
ProfileInfoLoader.cpp Remove unused private member variables uncovered by the recent changes to clang's -Wunused-private-field. 2012-07-20 22:05:57 +00:00
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp Release build: guard dump functions with 2012-09-12 05:06:18 +00:00
RegionPass.cpp Remove the the block_node_iterator of Region, replace it by the block_iterator. 2012-08-27 13:49:24 +00:00
RegionPrinter.cpp
ScalarEvolution.cpp Revert the series of commits starting with r166578 which introduced the 2012-11-01 08:07:29 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp Revert the series of commits starting with r166578 which introduced the 2012-11-01 08:07:29 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp Release build: guard dump functions with 2012-09-12 05:06:18 +00:00
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp Revert the majority of the next patch in the address space series: 2012-11-01 09:14:31 +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))

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