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Core: Avoid NaN seeds in RVV min/max reductions

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libeigen/eigen!2890
This commit is contained in:
Florian Maurin
2026-08-21 09:13:09 -07:00
committed by Rasmus Munk Larsen
parent b1f4d24c8a
commit 8763a05898
6 changed files with 100 additions and 86 deletions
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test/packetmath_fastmath.cpp
+38
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@@ -26,6 +26,28 @@ EIGEN_DONT_INLINE bool mask_any(const Scalar* mask) {
return Eigen::internal::predux_any(Eigen::internal::ploadu<Packet>(mask));
}
// Keep the finite inputs opaque while compiling the reduction itself with fast-math optimizations.
template <typename Scalar, typename Packet>
EIGEN_DONT_INLINE void reduce_minmax(const Scalar* input, Scalar* output) {
const Packet packet = Eigen::internal::ploadu<Packet>(input);
output[0] = Eigen::internal::predux_min(packet);
output[1] = Eigen::internal::predux_max(packet);
}
template <typename Scalar, typename Packet>
void verify_minmax_reduction() {
constexpr int packet_size = Eigen::internal::unpacket_traits<Packet>::size;
Scalar input[packet_size];
for (int i = 0; i < packet_size; ++i) {
input[i] = Scalar(i + 1);
}
Scalar output[2];
reduce_minmax<Scalar, Packet>(input, output);
VERIFY_IS_EQUAL(output[0], Scalar(1));
VERIFY_IS_EQUAL(output[1], Scalar(packet_size));
}
// Complementary to the opaque-mask calls: the all-ones mask flows straight
// from ptrue into the packet op, the way comparison-mask producers feed it,
// which gives constant folding under -ffinite-math-only a chance to see the
@@ -126,6 +148,8 @@ struct packetmath_fastmath_runner<Scalar, true> {
}
VERIFY((mask_any<Scalar, Packet>(mask)));
}
verify_minmax_reduction<Scalar, Packet>();
}
};
@@ -160,4 +184,18 @@ EIGEN_DECLARE_TEST(packetmath_fastmath) {
CALL_SUBTEST(packetmath_fastmath_runner<Eigen::half>::run());
CALL_SUBTEST(packetmath_fastmath_runner<Eigen::bfloat16>::run());
CALL_SUBTEST(extended_scalar_constant_runner<long double>::run());
#if defined(EIGEN_VECTORIZE_RVV10)
CALL_SUBTEST((verify_minmax_reduction<float, Eigen::internal::Packet1Xf>()));
CALL_SUBTEST((verify_minmax_reduction<float, Eigen::internal::Packet2Xf>()));
CALL_SUBTEST((verify_minmax_reduction<float, Eigen::internal::Packet4Xf>()));
CALL_SUBTEST((verify_minmax_reduction<double, Eigen::internal::Packet1Xd>()));
CALL_SUBTEST((verify_minmax_reduction<double, Eigen::internal::Packet2Xd>()));
CALL_SUBTEST((verify_minmax_reduction<double, Eigen::internal::Packet4Xd>()));
#endif
#if defined(EIGEN_VECTORIZE_RVV10FP16)
CALL_SUBTEST((verify_minmax_reduction<Eigen::half, Eigen::internal::Packet1Xh>()));
CALL_SUBTEST((verify_minmax_reduction<Eigen::half, Eigen::internal::Packet2Xh>()));
#endif
}