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History

Andrew Trick a454a863ad Clarify SCEV comments. We handle for(i=n; i>0; i -= s) by canonicalizing within SCEV to for(i=-n; i<0; i += s). llvm-svn: 193147		2013-10-22 05:09:40 +00:00
..
IPA	Disable inlining between sanitized and non-sanitized functions.	2013-08-08 08:22:39 +00:00
AliasAnalysis.cpp	Reimplement isPotentiallyReachable to make nocapture deduction much stronger.	2013-07-27 01:24:00 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp	Support in AAEvaluator to print alias queries of loads/stores with TBAA tags.	2013-03-22 22:34:41 +00:00
AliasDebugger.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
AliasSetTracker.cpp	In AliasSetTracker, do not change the alias set to "mod/ref" when adding	2013-09-12 20:15:50 +00:00
Analysis.cpp	Remove the very substantial, largely unmaintained legacy PGO	2013-10-02 15:42:23 +00:00
BasicAliasAnalysis.cpp	Use type helper functions	2013-09-27 22:18:51 +00:00
BlockFrequencyInfo.cpp	BlockFrequency: Bump up the entry frequency a bit.	2013-06-25 13:34:40 +00:00
BranchProbabilityInfo.cpp	Use SmallVectorImpl::iterator/const_iterator instead of SmallVector to avoid specifying the vector size.	2013-07-04 01:31:24 +00:00
CaptureTracking.cpp	CaptureTracking: Plug a loophole in the "too many uses" heuristic.	2013-10-03 13:24:02 +00:00
CFG.cpp	Add some constantness.	2013-08-20 23:04:15 +00:00
CFGPrinter.cpp
CMakeLists.txt	Remove the very substantial, largely unmaintained legacy PGO	2013-10-02 15:42:23 +00:00
CodeMetrics.cpp	Begin fleshing out an interface in TTI for modelling the costs of	2013-01-22 11:26:02 +00:00
ConstantFolding.cpp	Fix a constant folding address space place I missed.	2013-09-17 23:23:16 +00:00
CostModel.cpp	Move variable into assert to avoid unused variable warning.	2013-09-17 21:13:57 +00:00
DependenceAnalysis.cpp	Remove extraneous semicolon.	2013-08-06 16:40:40 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InstCount.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
InstructionSimplify.cpp	Teach MemoryBuiltins and InstructionSimplify that operator new never returns NULL.	2013-09-24 16:37:51 +00:00
Interval.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
IntervalPartition.cpp
IVUsers.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
LazyValueInfo.cpp	Use SmallVectorImpl::iterator/const_iterator instead of SmallVector to avoid specifying the vector size.	2013-07-04 01:31:24 +00:00
LibCallAliasAnalysis.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
LibCallSemantics.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
Lint.cpp	Fix lint assert on integer vector division	2013-08-26 23:29:33 +00:00
LLVMBuild.txt
Loads.cpp	Change GetPointerBaseWithConstantOffset's DataLayout argument from a	2013-01-31 02:00:45 +00:00
LoopInfo.cpp	Add 'const' qualifiers to static const char* variables.	2013-07-16 01:17:10 +00:00
LoopPass.cpp	Comment: try to clarify loop iteration order.	2013-07-20 23:10:31 +00:00
Makefile
MemDepPrinter.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
MemoryBuiltins.cpp	Rename DataLayout variables TD -> DL	2013-10-03 19:50:01 +00:00
MemoryDependenceAnalysis.cpp	Fix xemacs mode line, don't put them in .cpp files (just header files). No	2013-06-10 23:10:59 +00:00
ModuleDebugInfoPrinter.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
NoAliasAnalysis.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
PHITransAddr.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
PostDominators.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp	Reorder headers according to lint.	2013-08-21 21:14:19 +00:00
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Clarify SCEV comments.	2013-10-22 05:09:40 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	SCEVExpander: Fix a regression I introduced by to eagerly adding RAII objects.	2013-10-01 12:17:11 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
TargetTransformInfo.cpp	Costmodel: Add support for horizontal vector reductions	2013-09-17 18:06:50 +00:00
Trace.cpp	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
TypeBasedAliasAnalysis.cpp	TBAA: fix PR17620.	2013-10-22 01:40:25 +00:00
ValueTracking.cpp	Remove x86_sse42_crc32_64_8 intrinsic. It has no functional difference from x86_sse42_crc32_32_8 and was not mapped to a clang builtin. I'm not even sure why this form of the instruction is even called out explicitly in the docs. Also add AutoUpgrade support to convert it into the other intrinsic with appropriate trunc and zext.	2013-10-15 05:20:47 +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))

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