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[SCEV] Fix usage of invalid IP with FoldingSet 

Fix the use of invalid Insertion Point pointer with the UniqueSCEVs FoldingSet,
which caused memory corruption.
This commit is contained in:
Ehud Katz 2020-03-13 18:31:47 +02:00
parent 2543567c41
commit 18eae33122
1 changed files with 4 additions and 0 deletions
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4
llvm/lib/Analysis/ScalarEvolution.cpp
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@ -3339,6 +3339,10 @@ const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS,
} }
} }
// The Insertion Point (IP) might be invalid by now (due to UniqueSCEVs
// changes). Make sure we get a new one.
IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = new (SCEVAllocator) SCEVUDivExpr(ID.Intern(SCEVAllocator), SCEV *S = new (SCEVAllocator) SCEVUDivExpr(ID.Intern(SCEVAllocator),
LHS, RHS); LHS, RHS);
UniqueSCEVs.InsertNode(S, IP); UniqueSCEVs.InsertNode(S, IP);