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Reassociate: Avoid iterator invalidation.

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OpndPtrs stored pointers into the Opnd vector that became invalid when the
vector grows. Store indices instead. Sadly I only have a large testcase that
only triggers under valgrind, so I didn't include it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178793 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2013-04-04 21:15:42 +00:00
parent cb1de07007
commit ad2e252865
1 changed files with 12 additions and 7 deletions
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19
lib/Transforms/Scalar/Reassociate.cpp
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@ -143,9 +143,13 @@ namespace {
// So, if Rank(X) < Rank(Y) < Rank(Z), it means X is defined earlier
// than Y which is defined earlier than Z. Permute "x | 1", "Y & 2",
// "z" in the order of X-Y-Z is better than any other orders.
struct PtrSortFunctor {
bool operator()(XorOpnd * const &LHS, XorOpnd * const &RHS) {
return LHS->getSymbolicRank() < RHS->getSymbolicRank();
class PtrSortFunctor {
ArrayRef<XorOpnd> A;
public:
PtrSortFunctor(ArrayRef<XorOpnd> Array) : A(Array) {}
bool operator()(unsigned LHSIndex, unsigned RHSIndex) {
return A[LHSIndex].getSymbolicRank() < A[RHSIndex].getSymbolicRank();
}
};
private:
@ -1270,7 +1274,7 @@ Value *Reassociate::OptimizeXor(Instruction *I,
return 0;
SmallVector<XorOpnd, 8> Opnds;
SmallVector<XorOpnd*, 8> OpndPtrs;
SmallVector<unsigned, 8> OpndIndices;
Type *Ty = Ops[0].Op->getType();
APInt ConstOpnd(Ty->getIntegerBitWidth(), 0);
@ -1281,7 +1285,7 @@ Value *Reassociate::OptimizeXor(Instruction *I,
XorOpnd O(V);
O.setSymbolicRank(getRank(O.getSymbolicPart()));
Opnds.push_back(O);
OpndPtrs.push_back(&Opnds.back());
OpndIndices.push_back(Opnds.size() - 1);
} else
ConstOpnd ^= cast<ConstantInt>(V)->getValue();
}
@ -1290,13 +1294,14 @@ Value *Reassociate::OptimizeXor(Instruction *I,
// the same symbolic value cluster together. For instance, the input operand
// sequence ("x | 123", "y & 456", "x & 789") will be sorted into:
// ("x | 123", "x & 789", "y & 456").
std::sort(OpndPtrs.begin(), OpndPtrs.end(), XorOpnd::PtrSortFunctor());
std::sort(OpndIndices.begin(), OpndIndices.end(),
XorOpnd::PtrSortFunctor(Opnds));
// Step 3: Combine adjacent operands
XorOpnd *PrevOpnd = 0;
bool Changed = false;
for (unsigned i = 0, e = Opnds.size(); i < e; i++) {
XorOpnd *CurrOpnd = OpndPtrs[i];
XorOpnd *CurrOpnd = &Opnds[OpndIndices[i]];
// The combined value
Value *CV;