llvm-6502/lib/Analysis
Peter Collingbourne ce2b45bd7d IR: Do not consider available_externally linkage to be linker-weak.
From the linker's perspective, an available_externally global is equivalent
to an external declaration (per isDeclarationForLinker()), so it is incorrect
to consider it to be a weak definition.

Also clean up some logic in the dead argument elimination pass and clarify
its comments to better explain how its behavior depends on linkage,
introduce GlobalValue::isStrongDefinitionForLinker() and start using
it throughout the optimizers and backend.

Differential Revision: http://reviews.llvm.org/D10941

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241413 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-05 20:52:35 +00:00
..
IPA Delete whitespace at start of line. 2015-07-02 14:17:12 +00:00
AliasAnalysis.cpp [PM/AA] Hoist the AliasResult enum out of the AliasAnalysis class. 2015-06-22 02:16:51 +00:00
AliasAnalysisCounter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
AliasAnalysisEvaluator.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
AliasDebugger.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
AliasSetTracker.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
Analysis.cpp
AssumptionCache.cpp
BasicAliasAnalysis.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
BlockFrequencyInfo.cpp
BlockFrequencyInfoImpl.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
BranchProbabilityInfo.cpp
CaptureTracking.cpp [CaptureTracking] Avoid long compilation time on large basic blocks 2015-06-24 17:53:17 +00:00
CFG.cpp [CaptureTracking] Avoid long compilation time on large basic blocks 2015-06-24 17:53:17 +00:00
CFGPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
CFLAliasAnalysis.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
CGSCCPassManager.cpp
CMakeLists.txt Move VectorUtils from Transforms to Analysis to correct layering violation 2015-06-26 18:02:52 +00:00
CodeMetrics.cpp
ConstantFolding.cpp
CostModel.cpp
Delinearization.cpp Move delinearization from SCEVAddRecExpr to ScalarEvolution 2015-06-29 14:42:48 +00:00
DependenceAnalysis.cpp Move delinearization from SCEVAddRecExpr to ScalarEvolution 2015-06-29 14:42:48 +00:00
DivergenceAnalysis.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
DominanceFrontier.cpp
DomPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
InstCount.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
InstructionSimplify.cpp [InstSimplify] Allow folding of fdiv X, X with just NaNs ignored 2015-06-16 14:57:29 +00:00
Interval.cpp
IntervalPartition.cpp
IteratedDominanceFrontier.cpp
IVUsers.cpp
LazyCallGraph.cpp
LazyValueInfo.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
LibCallAliasAnalysis.cpp [PM/AA] Remove the Location typedef from the AliasAnalysis class now 2015-06-17 07:18:54 +00:00
LibCallSemantics.cpp Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
Lint.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
LLVMBuild.txt
Loads.cpp Take alignment into account in isSafeToLoadUnconditionally 2015-06-25 12:18:43 +00:00
LoopAccessAnalysis.cpp Move VectorUtils from Transforms to Analysis to correct layering violation 2015-06-26 18:02:52 +00:00
LoopInfo.cpp
LoopPass.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
Makefile
MemDepPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
MemDerefPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp [PM/AA] Hoist the AliasResult enum out of the AliasAnalysis class. 2015-06-22 02:16:51 +00:00
MemoryLocation.cpp [PM/AA] Split the location computation out of getArgLocation so the 2015-06-17 07:12:40 +00:00
ModuleDebugInfoPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
NoAliasAnalysis.cpp [PM/AA] Remove the Location typedef from the AliasAnalysis class now 2015-06-17 07:18:54 +00:00
PHITransAddr.cpp [GVN] Set proper debug locations for some instructions created by GVN. 2015-06-10 17:37:38 +00:00
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
ScalarEvolution.cpp Move delinearization from SCEVAddRecExpr to ScalarEvolution 2015-06-29 14:42:48 +00:00
ScalarEvolutionAliasAnalysis.cpp [PM/AA] Hoist the AliasResult enum out of the AliasAnalysis class. 2015-06-22 02:16:51 +00:00
ScalarEvolutionExpander.cpp [LSR] canonicalize Prod*(1<<C) to Prod<<C 2015-06-24 19:28:40 +00:00
ScalarEvolutionNormalization.cpp
ScopedNoAliasAA.cpp [PM/AA] Hoist the AliasResult enum out of the AliasAnalysis class. 2015-06-22 02:16:51 +00:00
SparsePropagation.cpp
StratifiedSets.h Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
TargetLibraryInfo.cpp
TargetTransformInfo.cpp Add a routine to TargetTransformInfo that will allow targets to look 2015-07-02 01:11:47 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
ValueTracking.cpp IR: Do not consider available_externally linkage to be linker-weak. 2015-07-05 20:52:35 +00:00
VectorUtils.cpp Move VectorUtils from Transforms to Analysis to correct layering violation 2015-06-26 18:02:52 +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))

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