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History

Nick Lewycky 7425820374 Change CaptureTracking to pass a Use* instead of a Value* when a value is captured. This allows the tracker to look at the specific use, which may be especially interesting for function calls. Use this to fix 'nocapture' deduction in FunctionAttrs. The existing one does not iterate until a fixpoint and does not guarantee that it produces the same result regardless of iteration order. The new implementation builds up a graph of how arguments are passed from function to function, and uses a bottom-up walk on the argument-SCCs to assign nocapture. This gets us nocapture more often, and does so rather efficiently and independent of iteration order. llvm-svn: 147327		2011-12-28 23:24:21 +00:00
..
IPA	LLVMBuild: Remove trailing newline, which irked me.	2011-12-12 19:48:00 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp	Refactor code to use new attribute getters on CallSite for NoCapture and ByVal.	2011-11-20 19:09:04 +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	Change CaptureTracking to pass a Use* instead of a Value* when a value is	2011-12-28 23:24:21 +00:00
CFGPrinter.cpp	Remove all remaining uses of Value::getNameStr().	2011-11-15 16:27:03 +00:00
CMakeLists.txt	build/CMake: Finish removal of add_llvm_library_dependencies.	2011-11-29 19:25:30 +00:00
ConstantFolding.cpp	Switch llvm.cttz and llvm.ctlz to accept a second i1 parameter which	2011-12-12 04:26:04 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Unweaken vtables as per http://llvm.org/docs/CodingStandards.html#ll_virtual_anch	2011-12-20 02:50:00 +00:00
DIBuilder.cpp	In DICompositeType, referenced to derived type is either metadata or null.	2011-12-16 17:51:31 +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
InlineCost.cpp	Continue counting intrinsics as instructions (except when they aren't, such as	2011-12-21 20:26:03 +00:00
InstCount.cpp
InstructionSimplify.cpp	Add support for vectors of pointers.	2011-12-05 06:29:09 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp	Clear the new cache.	2011-12-03 15:19:55 +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
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	Change CaptureTracking to pass a Use* instead of a Value* when a value is	2011-12-28 23:24:21 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp
PathProfileInfo.cpp
PathProfileVerifier.cpp	Remove all remaining uses of Value::getNameStr().	2011-11-15 16:27:03 +00:00
PHITransAddr.cpp	Move Instruction::isSafeToSpeculativelyExecute out of VMCore and	2011-12-14 23:49:11 +00:00
PostDominators.cpp
ProfileEstimatorPass.cpp	Remove all remaining uses of Value::getNameStr().	2011-11-15 16:27:03 +00:00
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp	Remove all remaining uses of Value::getNameStr().	2011-11-15 16:27:03 +00:00
ProfileVerifierPass.cpp	Move code into anonymous namespaces.	2011-11-26 23:01:57 +00:00
README.txt
RegionInfo.cpp	Missed some users of Value::getNameStr.	2011-11-15 18:30:06 +00:00
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Fix a few more places where TargetData/TargetLibraryInfo is not being passed.	2011-12-02 01:26:24 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	LSR: Fix another corner case in expansion of postinc users.	2011-12-20 01:42:24 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp	Remove all remaining uses of Value::getNameStr().	2011-11-15 16:27:03 +00:00
Trace.cpp	Remove all remaining uses of Value::getNameStr().	2011-11-15 16:27:03 +00:00
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	ComputeMaskedBits: Make knownzero computation more aggressive for ctlz with undef zero.	2011-12-24 17:31:46 +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))

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