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Fix a crash in Dependency Analysis.

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This crash in Dependency analysis is because we assume here that in case of UsefulGEP
both source and destination have the same number of operands which may not be true.
This incorrect assumption results in crash while populating Pairs. Fix the same.

This crash was observed during lnt regression for code such as-
  struct s{
    int A[10][10];
    int C[10][10][10]; 
  } S;
  void dep_constraint_crash_test(int k,int N)  {
     for( int i=0;i<N;i++)
       for( int j=0;j<N;j++)
         S.A[0][0] = S.C[0][0][k];
  }
Review: http://reviews.llvm.org/D8162



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231784 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Karthik Bhat
2015-03-10 13:31:03 +00:00
parent b02d16e0e7
commit 5f9683f54f
2 changed files with 57 additions and 6 deletions
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12
lib/Analysis/DependenceAnalysis.cpp
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@@ -3346,9 +3346,9 @@ DependenceAnalysis::depends(Instruction *Src, Instruction *Dst,
DEBUG(dbgs() << " SrcPtrSCEV = " << *SrcPtrSCEV << "\n");
DEBUG(dbgs() << " DstPtrSCEV = " << *DstPtrSCEV << "\n");
UsefulGEP =
isLoopInvariant(SrcPtrSCEV, LI->getLoopFor(Src->getParent())) &&
isLoopInvariant(DstPtrSCEV, LI->getLoopFor(Dst->getParent()));
UsefulGEP = isLoopInvariant(SrcPtrSCEV, LI->getLoopFor(Src->getParent())) &&
isLoopInvariant(DstPtrSCEV, LI->getLoopFor(Dst->getParent())) &&
(SrcGEP->getNumOperands() == DstGEP->getNumOperands());
}
unsigned Pairs = UsefulGEP ? SrcGEP->idx_end() - SrcGEP->idx_begin() : 1;
SmallVector<Subscript, 4> Pair(Pairs);
@@ -3773,9 +3773,9 @@ const SCEV *DependenceAnalysis::getSplitIteration(const Dependence &Dep,
SrcGEP->getPointerOperandType() == DstGEP->getPointerOperandType()) {
const SCEV *SrcPtrSCEV = SE->getSCEV(SrcGEP->getPointerOperand());
const SCEV *DstPtrSCEV = SE->getSCEV(DstGEP->getPointerOperand());
UsefulGEP =
isLoopInvariant(SrcPtrSCEV, LI->getLoopFor(Src->getParent())) &&
isLoopInvariant(DstPtrSCEV, LI->getLoopFor(Dst->getParent()));
UsefulGEP = isLoopInvariant(SrcPtrSCEV, LI->getLoopFor(Src->getParent())) &&
isLoopInvariant(DstPtrSCEV, LI->getLoopFor(Dst->getParent())) &&
(SrcGEP->getNumOperands() == DstGEP->getNumOperands());
}
unsigned Pairs = UsefulGEP ? SrcGEP->idx_end() - SrcGEP->idx_begin() : 1;
SmallVector<Subscript, 4> Pair(Pairs);