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dcrtpoly-impl: avoid integer overflow #9

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11 changes: 6 additions & 5 deletions src/core/include/lattice/hal/default/dcrtpoly-impl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1776,7 +1776,7 @@ void DCRTPolyImpl<VecType>::FastBaseConvqToBskMontgomery(
mu.push_back(q.ComputeMu());

// first we twist xi by mtilde*(q/qi)^-1 mod qi
std::vector<NativeInteger> ximtildeQHatModqi(n * numQ);
std::vector<NativeInteger> ximtildeQHatModqi(static_cast<size_t>(n) * static_cast<size_t>(numQ));
std::vector<uint64_t> result_mtilde(n, 0);
for (uint32_t i = 0; i < numQ; ++i) {
const auto& mtildeQHatInvModqi = mtildeQHatInvModq[i];
Expand Down Expand Up @@ -1862,29 +1862,30 @@ void DCRTPolyImpl<VecType>::FastRNSFloorq(
m_vectors[i][k].ModMulFastConstEq(tqDivqiModqi, moduliQi, tqDivqiModqiPrecon);
}

std::vector<NativeInteger> txiqiDivqModqi(n * numBsk);
std::vector<NativeInteger> txiqiDivqModqi(static_cast<size_t>(n) * static_cast<size_t>(numBsk));
#pragma omp parallel for num_threads(OpenFHEParallelControls.GetThreadLimit(numBsk))
for (uint32_t j = 0; j < numBsk; ++j) {
const auto& moduliBskj = moduliBsk[j];
const auto& tDivqModBskj = tQInvModbsk[j];
const auto& tDivqModBskjPrecon = tQInvModbskPrecon[j];
for (uint32_t k = 0; k < n; ++k) {
size_t idx = static_cast<size_t>(j) * static_cast<size_t>(n) + k;
#if defined(HAVE_INT128) && NATIVEINT == 64
DoubleNativeInt aq = 0;
for (uint32_t i = 0; i < numQ; ++i) {
const auto& xi = m_vectors[i][k];
aq += Mul128(xi.template ConvertToInt<uint64_t>(), qInvModbsk[i][j].ConvertToInt<uint64_t>());
}
txiqiDivqModqi[j * n + k] = BarrettUint128ModUint64(aq, moduliBskj.ConvertToInt(), modbskBarrettMu[j]);
txiqiDivqModqi[idx] = BarrettUint128ModUint64(aq, moduliBskj.ConvertToInt(), modbskBarrettMu[j]);
#else
for (uint32_t i = 0; i < numQ; ++i) {
const auto& xi = m_vectors[i][k];
txiqiDivqModqi[j * n + k].ModAddFastEq(xi.ModMul(qInvModbsk[i][j], moduliBskj, mu[j]), moduliBskj);
txiqiDivqModqi[idx].ModAddFastEq(xi.ModMul(qInvModbsk[i][j], moduliBskj, mu[j]), moduliBskj);
}
#endif
// now we have FastBaseConv( |t*ct|q, q, Bsk ) in txiqiDivqModqi
m_vectors[numQ + j][k].ModMulFastConstEq(tDivqModBskj, moduliBskj, tDivqModBskjPrecon);
m_vectors[numQ + j][k].ModSubFastEq(txiqiDivqModqi[j * n + k], moduliBskj);
m_vectors[numQ + j][k].ModSubFastEq(txiqiDivqModqi[idx], moduliBskj);
}
}
}
Expand Down