llvm-6502/lib/Analysis
Silviu Baranga f283cd9acf Don't rely on the DepCands iteration order when constructing checking pointer groups
Summary:
The checking pointer group construction algorithm relied on the iteration on DepCands.
We would need the same leaders across runs and the same iteration order over the underlying std::set for determinism.

This changes the algorithm to process the pointers in the order in which they were added to the runtime check, which is deterministic.
We need to update the tests, since the order in which pointers appear has changed.

No new tests were added, since it is impossible to test for non-determinism.

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11064

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241809 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-09 15:18:25 +00:00
..
IPA Rename llvm.frameescape and llvm.framerecover to localescape and localrecover 2015-07-07 22:25:32 +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 Allow constfolding of llvm.sin.* and llvm.cos.* intrinsics 2015-07-08 03:55:47 +00:00
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 Don't rely on the DepCands iteration order when constructing checking pointer groups 2015-07-09 15:18:25 +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 Make TargetTransformInfo keeping a reference to the Module DataLayout 2015-07-09 02:08:42 +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))

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