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History

Benjamin Kramer 2a3719125f LVI: Recognize the form instcombine canonicalizes range checks into when forming constant ranges. This could probably be made a lot smarter, but this is a common case and doesn't require LVI to scan a lot of code. With this change CVP can optimize away the "shift == 0" case in Hashing.h that only gets hit when "shift" is in a range not containing 0. llvm-svn: 151919		2012-03-02 15:34:43 +00:00
..
IPA	LLVMBuild: Remove trailing newline, which irked me.	2011-12-12 19:48:00 +00:00
AliasAnalysis.cpp	Move isKnownNonNull from private implementation detail of BasicAA to a public	2012-02-25 10:56:28 +00:00
AliasAnalysisCounter.cpp	Persuade GCC that there is nothing worth warning about here (there isn't).	2012-02-05 14:20:11 +00:00
AliasAnalysisEvaluator.cpp	Remove unnecessary default cases in switches that cover all enum values.	2012-01-10 16:47:17 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp	Have AliasSet::aliasesUnknownInst use pointer TBAA info when available	2012-02-10 15:52:39 +00:00
Analysis.cpp
BasicAliasAnalysis.cpp	Duncan pointed out that if the alignment isn't explicitly specified, it defaults to the ABI alignment. Given that, make this code a bit more aggressive in such cases.	2012-02-27 23:16:46 +00:00
BlockFrequencyInfo.cpp	Add some constantness to BranchProbabilityInfo and BlockFrequnencyInfo.	2011-12-20 20:03:10 +00:00
BranchProbabilityInfo.cpp	Make the unreachable probability much much heavier. The previous	2011-12-22 09:26:37 +00:00
CaptureTracking.cpp	Move includes to the .cpp file.	2012-01-17 22:16:31 +00:00
CFGPrinter.cpp
CMakeLists.txt	build/CMake: Finish removal of add_llvm_library_dependencies.	2011-11-29 19:25:30 +00:00
ConstantFolding.cpp	Convert assert(0) to llvm_unreachable	2012-02-07 05:05:23 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Make this a bit prettier and more obvious when a derived type isn't	2012-02-20 18:04:39 +00:00
DIBuilder.cpp	Add support for runtime languages on our forward declarations.	2012-02-20 18:04:14 +00:00
DominanceFrontier.cpp	Unweaken vtables as per http://llvm.org/docs/CodingStandards.html#ll_virtual_anch	2011-12-20 02:50:00 +00:00
DomPrinter.cpp	remove the blank line from previous ci.	2012-02-04 03:18:47 +00:00
InlineCost.cpp	Use precomputed BB size instead of BB->size().	2012-01-25 18:54:13 +00:00
InstCount.cpp
InstructionSimplify.cpp	Reinstate the optimization from r151449 with a fix to not turn 'gep %x' into	2012-02-26 02:09:49 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Put all IVUsers in the processed set. Allow querying IVUsers with isIVUserOrOperand.	2012-01-06 21:41:55 +00:00
LazyValueInfo.cpp	LVI: Recognize the form instcombine canonicalizes range checks into when forming constant ranges.	2012-03-02 15:34:43 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Fix a few more places where TargetData/TargetLibraryInfo is not being passed.	2011-12-02 01:26:24 +00:00
LLVMBuild.txt	LLVMBuild: Introduce a common section which currently has a list of the	2011-12-12 22:45:54 +00:00
Loads.cpp
LoopDependenceAnalysis.cpp	More dead code removal (using -Wunreachable-code)	2012-01-20 21:51:11 +00:00
LoopInfo.cpp	Move Instruction::isSafeToSpeculativelyExecute out of VMCore and	2011-12-14 23:49:11 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Fix a stupid typo in MemDepPrinter.	2011-12-14 02:54:39 +00:00
MemoryBuiltins.cpp	Validate the return type when checking if a function is malloc.	2011-11-23 17:58:47 +00:00
MemoryDependenceAnalysis.cpp	Don't call dominates on unreachable instructions. Should fix the dragonegg	2012-02-26 05:30:08 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp	[unwind removal] We no longer have 'unwind' instructions being generated, so	2012-02-06 21:16:41 +00:00
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp	More dead code removal (using -Wunreachable-code)	2012-01-20 21:51:11 +00:00
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp	Move code into anonymous namespaces.	2011-11-26 23:01:57 +00:00
README.txt
RegionInfo.cpp	Remove extra semi-colons.	2012-02-22 17:25:00 +00:00
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	switch SCEV to use the new ConstantFoldLoadThroughGEPIndices function	2012-01-24 05:49:24 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Fix this assert. IP can point to an instruction with strange dominance	2012-02-27 02:13:03 +00:00
ScalarEvolutionNormalization.cpp	More dead code removal (using -Wunreachable-code)	2012-01-20 21:51:11 +00:00
SparsePropagation.cpp	SwitchInst refactoring.	2012-02-01 07:49:51 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	Remove some dead code and tidy things up now that vectors use ConstantDataVector	2012-02-06 21:56:39 +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))

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