[llvm] r178793 - Reassociate: Avoid iterator invalidation.
Benjamin Kramer
benny.kra at googlemail.com
Thu Apr 4 14:15:42 PDT 2013
Author: d0k
Date: Thu Apr 4 16:15:42 2013
New Revision: 178793
URL: http://llvm.org/viewvc/llvm-project?rev=178793&view=rev
Log:
Reassociate: Avoid iterator invalidation.
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.
Modified:
llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp?rev=178793&r1=178792&r2=178793&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp Thu Apr 4 16:15:42 2013
@@ -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(Instruct
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(Instruct
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(Instruct
// 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;
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