llvm-6502/lib/Analysis
Jiangning Liu de3646b278 Add two thresholds lvi-overdefined-BB-threshold and lvi-overdefined-threshold
for LVI algorithm. For a specific value to be lowered, when the number of basic
blocks being checked for overdefined lattice value is larger than
lvi-overdefined-BB-threshold, or the times of encountering overdefined value
for a single basic block is larger than lvi-overdefined-threshold, the LVI
algorithm will stop further lowering the lattice value.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218231 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-22 02:23:05 +00:00
..
IPA Add functions for finding ephemeral values 2014-09-07 13:49:57 +00:00
AliasAnalysis.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
Analysis.cpp Add a CFL Alias Analysis implementation 2014-09-02 21:43:13 +00:00
AssumptionTracker.cpp Add an Assumption-Tracking Pass 2014-09-07 12:44:26 +00:00
BasicAliasAnalysis.cpp Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
BlockFrequencyInfo.cpp
BlockFrequencyInfoImpl.cpp
BranchProbabilityInfo.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
CaptureTracking.cpp Match semantics of PointerMayBeCapturedBefore to its name by default 2014-07-21 21:30:22 +00:00
CFG.cpp
CFGPrinter.cpp Modernize raw_fd_ostream's constructor a bit. 2014-08-25 18:16:47 +00:00
CFLAliasAnalysis.cpp [CFLAA] Remove one final initializer list 2014-09-03 00:06:47 +00:00
CGSCCPassManager.cpp
CMakeLists.txt Add file to CMake build as well. 2014-09-18 00:39:20 +00:00
CodeMetrics.cpp Add functions for finding ephemeral values 2014-09-07 13:49:57 +00:00
ConstantFolding.cpp Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size. 2014-08-21 05:55:13 +00:00
CostModel.cpp
Delinearization.cpp
DependenceAnalysis.cpp Analysis: cleanup 2014-08-26 02:03:40 +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 InstSimplify: Don't allow (x srem y) urem y -> x srem y 2014-09-17 04:16:35 +00:00
Interval.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
IntervalPartition.cpp
IVUsers.cpp Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size. 2014-08-21 05:55:13 +00:00
JumpInstrTableInfo.cpp
LazyCallGraph.cpp
LazyValueInfo.cpp Add two thresholds lvi-overdefined-BB-threshold and lvi-overdefined-threshold 2014-09-22 02:23:05 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
LLVMBuild.txt
Loads.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
LoopInfo.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PHITransAddr.cpp Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp Make use @llvm.assume for loop guards in ScalarEvolution 2014-09-07 21:37:59 +00:00
ScalarEvolutionAliasAnalysis.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
ScalarEvolutionExpander.cpp Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
ScalarEvolutionNormalization.cpp Fix typos in comments, NFC 2014-08-29 21:53:01 +00:00
ScopedNoAliasAA.cpp Add override to overriden virtual methods, remove virtual keywords. 2014-09-03 11:41:21 +00:00
SparsePropagation.cpp
StratifiedSets.h [CFLAA] And even more MSVC fixes 2014-09-02 23:50:01 +00:00
TargetTransformInfo.cpp Add a new pass FunctionTargetTransformInfo. This pass serves as a 2014-09-18 00:34:14 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp Add scoped-noalias metadata 2014-07-24 14:25:39 +00:00
ValueTracking.cpp Fix an ODR violation consisting of two 'struct Query' in the global namespace. 2014-09-12 08:56:53 +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))

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