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History

Sanjoy Das 0cdde3ea1f Teach ScalarEvolution to exploit min and max expressions when proving isKnownPredicate. The motivation for this change is to optimize away checks in loops like this: limit = min(t, len) for (i = 0 to limit) if (i >= len \|\| i < 0) throw_array_of_of_bounds(); a[i] = ... Differential Revision: http://reviews.llvm.org/D6635 llvm-svn: 224285		2014-12-15 22:50:15 +00:00
..
IPA	Remove the unused FindUsedTypes pass.	2014-11-24 20:53:26 +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
AssumptionTracker.cpp	Clean up assume intrinsic pattern matching, no need to check that the argument is a value.	2014-10-25 18:09:01 +00:00
BasicAliasAnalysis.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
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	Modernize raw_fd_ostream's constructor a bit.	2014-08-25 18:16:47 +00:00
CFLAliasAnalysis.cpp	Remove redundant virtual on overriden functions.	2014-11-14 19:06:36 +00:00
CGSCCPassManager.cpp
CMakeLists.txt	Add file to CMake build as well.	2014-09-18 00:39:20 +00:00
CodeMetrics.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
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	ConstantFold, InstSimplify: undef >>a x can be either -1 or 0, choose 0	2014-12-10 21:58:15 +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	LazyValueInfo: Actually re-visit partially solved block-values in solveBlockValue()	2014-11-25 17:23:05 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp	remove function names from comments; NFC	2014-10-21 18:26:57 +00:00
Lint.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
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	Relax an assert a bit to avoid a crash on unreachable code.	2014-12-01 02:55:24 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp	Simplify code. No functionality change.	2014-10-05 12:21:57 +00:00
PHITransAddr.cpp	Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.)	2014-09-07 18:57:58 +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	Teach ScalarEvolution to exploit min and max expressions when proving	2014-12-15 22:50:15 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.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
ScalarEvolutionNormalization.cpp	Fix typos in comments, NFC	2014-08-29 21:53:01 +00:00
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	ValueTracking: Don't recurse too deeply in computeKnownBitsFromAssume	2014-12-12 23:59:29 +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.

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

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))

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