llvm-6502/lib/Analysis
Chandler Carruth 5a9cd4d44e [PM] Split the AssumptionTracker immutable pass into two separate APIs:
a cache of assumptions for a single function, and an immutable pass that
manages those caches.

The motivation for this change is two fold. Immutable analyses are
really hacks around the current pass manager design and don't exist in
the new design. This is usually OK, but it requires that the core logic
of an immutable pass be reasonably partitioned off from the pass logic.
This change does precisely that. As a consequence it also paves the way
for the *many* utility functions that deal in the assumptions to live in
both pass manager worlds by creating an separate non-pass object with
its own independent API that they all rely on. Now, the only bits of the
system that deal with the actual pass mechanics are those that actually
need to deal with the pass mechanics.

Once this separation is made, several simplifications become pretty
obvious in the assumption cache itself. Rather than using a set and
callback value handles, it can just be a vector of weak value handles.
The callers can easily skip the handles that are null, and eventually we
can wrap all of this up behind a filter iterator.

For now, this adds boiler plate to the various passes, but this kind of
boiler plate will end up making it possible to port these passes to the
new pass manager, and so it will end up factored away pretty reasonably.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225131 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-04 12:03:27 +00:00
..
IPA [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
AliasAnalysis.cpp Sink store based on alias analysis 2014-12-15 14:09:53 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp AliasSet: Simplify mergeSetIn 2014-11-19 19:36:18 +00:00
Analysis.cpp Revert "Don't make assumptions about the name of private global variables." 2014-11-15 02:03:53 +00:00
AssumptionCache.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
BasicAliasAnalysis.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
BlockFrequencyInfo.cpp
BlockFrequencyInfoImpl.cpp BFI: Saturate when combining edges to a successor 2014-12-05 19:13:42 +00:00
BranchProbabilityInfo.cpp IR: Split Metadata from Value 2014-12-09 18:38:53 +00:00
CaptureTracking.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
CFG.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
CFGPrinter.cpp
CFLAliasAnalysis.cpp Remove redundant virtual on overriden functions. 2014-11-14 19:06:36 +00:00
CGSCCPassManager.cpp
CMakeLists.txt [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
CodeMetrics.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
ConstantFolding.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
CostModel.cpp
Delinearization.cpp
DependenceAnalysis.cpp [DependenceAnalysis] Allow subscripts of different types 2014-11-16 16:52:44 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
FunctionTargetTransformInfo.cpp Add a new pass FunctionTargetTransformInfo. This pass serves as a 2014-09-18 00:34:14 +00:00
InstCount.cpp
InstructionSimplify.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
JumpInstrTableInfo.cpp Add Forward Control-Flow Integrity. 2014-11-11 21:08:02 +00:00
LazyCallGraph.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
LazyValueInfo.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp remove function names from comments; NFC 2014-10-21 18:26:57 +00:00
Lint.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
LLVMBuild.txt
Loads.cpp Revert r220349 to re-instate r220277 with a fix for PR21330 -- quite 2014-11-25 08:20:27 +00:00
LoopInfo.cpp Revert "IR: MDNode => Value" 2014-11-11 21:30:22 +00:00
LoopPass.cpp Fix assertion in LICM doFinalization() 2014-09-24 16:48:31 +00:00
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
MemoryDependenceAnalysis.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp Simplify code. No functionality change. 2014-10-05 12:21:57 +00:00
PHITransAddr.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
PostDominators.cpp
PtrUseVisitor.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
ScalarEvolutionNormalization.cpp
ScopedNoAliasAA.cpp Revert "IR: MDNode => Value" 2014-11-11 21:30:22 +00:00
SparsePropagation.cpp
StratifiedSets.h Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
TargetTransformInfo.cpp Loop Vectorizer minor changes in the code - 2014-12-14 09:43:50 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp IR: Split Metadata from Value 2014-12-09 18:38:53 +00:00
ValueTracking.cpp [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +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))

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