6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-08-25 00:29:20 +00:00
Code Issues Projects Releases Wiki Activity
5d3a9d6339
llvm-6502/include/llvm/Analysis
History
Adam Nemet 50b9e7f7d4 [getUnderlyingOjbects] Analyze loop PHIs further to remove false positives 
Specifically, if a pointer accesses different underlying objects in each
iteration, don't look through the phi node defining the pointer.

The motivating case is the underlyling-objects-2.ll testcase.  Consider
the loop nest:

  int **A;
  for (i)
    for (j)
       A[i][j] = A[i-1][j] * B[j]

This loop is transformed by Load-PRE to stash away A[i] for the next
iteration of the outer loop:

  Curr = A[0];          // Prev_0
  for (i: 1..N) {
    Prev = Curr;        // Prev = PHI (Prev_0, Curr)
    Curr = A[i];
    for (j: 0..N)
       Curr[j] = Prev[j] * B[j]
  }

Since A[i] and A[i-1] are likely to be independent pointers,
getUnderlyingObjects should not assume that Curr and Prev share the same
underlying object in the inner loop.

If it did we would try to dependence-analyze Curr and Prev and the
analysis of the corresponding SCEVs would fail with non-constant
distance.

To fix this, the getUnderlyingObjects API is extended with an optional
LoopInfo parameter.  This is effectively what controls whether we want
the above behavior or the original.  Currently, I only changed to use
this approach for LoopAccessAnalysis.

The other testcase is to guard the opposite case where we do want to
look through the loop PHI.  If we step through an array by incrementing
a pointer, the underlying object is the incoming value of the phi as the
loop is entered.

Fixes rdar://problem/19566729

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235634 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-23 20:09:20 +00:00
..
AliasAnalysis.h Add new getModRefInfo API to determine whether an Instruction and a call modify the same memory 2015-04-13 23:25:41 +00:00
AliasSetTracker.h Remove explicit copy assignment operator in favor of the implicit/default to avoid disabling/deprecating the implicit copy ctor. 2015-03-03 19:29:13 +00:00
AssumptionCache.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
BlockFrequencyInfo.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
BlockFrequencyInfoImpl.h Remove 4,096 loop scale limitation. 2015-04-01 17:42:27 +00:00
BranchProbabilityInfo.h [stack protector] Set edge weights for newly created basic blocks. 2014-12-01 04:27:03 +00:00
CallGraph.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
CallGraphSCCPass.h [C++11] Add 'override' keyword to virtual methods that override their base class. 2014-03-05 07:30:04 +00:00
CallPrinter.h Added -view-callgraph module pass. 2013-01-11 17:28:14 +00:00
CaptureTracking.h Match semantics of PointerMayBeCapturedBefore to its name by default 2014-07-21 21:30:22 +00:00
CFG.h [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
CFGPrinter.h Tweak CFGPrinter to wrap very long names. 2014-08-20 17:38:12 +00:00
CGSCCPassManager.h [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
CodeMetrics.h [PM] Split the AssumptionTracker immutable pass into two separate APIs: 2015-01-04 12:03:27 +00:00
ConstantFolding.h DataLayout is mandatory, update the API to reflect it with references. 2015-03-10 02:37:25 +00:00
DependenceAnalysis.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
DominanceFrontier.h These functions are not actually defined for NDEBUG or !LLVM_DUMP_ENABLED, so guarding the declarations as well. NFC, silences MSVC warnings in release builds. 2014-10-24 15:16:39 +00:00
DominanceFrontierImpl.h Fix ODR violations caused by putting anonymous namespaces in header files (and 2015-03-17 02:36:51 +00:00
DomPrinter.h
DOTGraphTraitsPass.h Modernize raw_fd_ostream's constructor a bit. 2014-08-25 18:16:47 +00:00
InlineCost.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
InstructionSimplify.h DataLayout is mandatory, update the API to reflect it with references. 2015-03-10 02:37:25 +00:00
Interval.h Remove copy ctors that did the same thing as the default one. 2014-03-11 11:32:49 +00:00
IntervalIterator.h Remove use of reserved identifier 2015-03-15 01:37:01 +00:00
IntervalPartition.h [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
IteratedDominanceFrontier.h Move IDF Calculation to a separate file, expose an interface to it. 2015-04-21 19:13:02 +00:00
IVUsers.h DataLayout is mandatory, update the API to reflect it with references. 2015-03-10 02:37:25 +00:00
JumpInstrTableInfo.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
LazyCallGraph.h Revert r225854: [PM] Move the LazyCallGraph printing functionality to 2015-01-14 00:27:45 +00:00
LazyValueInfo.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
LibCallAliasAnalysis.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
LibCallSemantics.h Stop calling DwarfEHPrepare from WinEHPrepare 2015-03-12 00:36:20 +00:00
Lint.h
Loads.h DataLayout is mandatory, update the API to reflect it with references. 2015-03-10 02:37:25 +00:00
LoopAccessAnalysis.h [getUnderlyingOjbects] Analyze loop PHIs further to remove false positives 2015-04-23 20:09:20 +00:00
LoopInfo.h Transforms: Use the new DebugLoc API, NFC 2015-03-30 19:49:49 +00:00
LoopInfoImpl.h Replace loop doing postorder walk with postorder iterator 2015-04-16 04:28:32 +00:00
LoopIterator.h Remove unneeded #includes. 2013-02-09 13:29:10 +00:00
LoopPass.h Fix assertion in LICM doFinalization() 2014-09-24 16:48:31 +00:00
MemoryBuiltins.h DataLayout is mandatory, update the API to reflect it with references. 2015-03-10 02:37:25 +00:00
MemoryDependenceAnalysis.h Revamp PredIteratorCache interface to be cleaner. 2015-04-21 21:11:50 +00:00
Passes.h Divergence analysis for GPU programs 2015-04-10 05:03:50 +00:00
PHITransAddr.h DataLayout is mandatory, update the API to reflect it with references. 2015-03-10 02:37:25 +00:00
PostDominators.h Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
PtrUseVisitor.h [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
RegionInfo.h Remove empty non-virtual destructors or mark them =default when non-public 2015-04-11 15:32:26 +00:00
RegionInfoImpl.h Make it obvious that we're iterating over a range of pointers. 2015-04-16 12:43:07 +00:00
RegionIterator.h Remove explicit RNSuccIterator copy assignment in favor of implicit default 2015-03-04 07:51:50 +00:00
RegionPass.h [C++11] Add 'override' keyword to virtual methods that override their base class. 2014-03-05 07:30:04 +00:00
RegionPrinter.h
ScalarEvolution.h [SCEV] Look at backedge dominating conditions (re-land r233447). 2015-04-01 18:24:06 +00:00
ScalarEvolutionExpander.h [SCEVExpander] Fix comments for functions. NFC. 2015-04-14 03:20:40 +00:00
ScalarEvolutionExpressions.h [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
ScalarEvolutionNormalization.h Fix include guards so they exactly match file names. 2013-01-10 00:45:19 +00:00
SparsePropagation.h Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition. 2015-02-15 22:54:22 +00:00
TargetFolder.h [opaque pointer types] Push explicit type parameter for geps through the constant folders 2015-04-03 01:15:16 +00:00
TargetLibraryInfo.def Move TargetLibraryInfo data from two files into one common .def file. 2015-03-03 23:41:58 +00:00
TargetLibraryInfo.h TLI: Add addVectorizableFunctionsFromVecLib. 2015-03-17 19:50:55 +00:00
TargetTransformInfo.h [LoopUnrollRuntime] Avoid high-cost trip count computation. 2015-04-14 03:20:38 +00:00
TargetTransformInfoImpl.h [CallSite] Make construction from Value* (or Instruction*) explicit. 2015-04-10 14:50:08 +00:00
Trace.h Fix include guards so they exactly match file names. 2013-01-10 00:45:19 +00:00
ValueTracking.h [getUnderlyingOjbects] Analyze loop PHIs further to remove false positives 2015-04-23 20:09:20 +00:00