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bug #1631: fix compilation with ARM NEON and clang, and cleanup the weird pshiftright_and_cast and pcast_and_shiftleft functions.

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This commit is contained in:
Gael Guennebaud
2018-11-27 23:45:00 +01:00
parent a1a5fbbd21
commit b131a4db24
8 changed files with 124 additions and 90 deletions
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40
Eigen/src/Core/GenericPacketMath.h
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@@ -219,7 +219,13 @@ pxor(const Packet& a, const Packet& b) { return a ^ b; }
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pandnot(const Packet& a, const Packet& b) { return a & (!b); }
/** \internal \returns \a a shifted by N bits */
/** \internal \returns \a a shifted by N bits to the right */
template<int N> EIGEN_DEVICE_FUNC inline int
pshiftright(const int& a) { return a >> N; }
template<int N> EIGEN_DEVICE_FUNC inline long int
pshiftright(const long int& a) { return a >> N; }
/** \internal \returns \a a shifted by N bits to the left */
template<int N> EIGEN_DEVICE_FUNC inline int
pshiftleft(const int& a) { return a << N; }
template<int N> EIGEN_DEVICE_FUNC inline long int
@@ -654,41 +660,17 @@ pinsertlast(const Packet& a, typename unpacket_traits<Packet>::type b)
* Some generic implementations to be used by implementors
***************************************************************************/
/** \internal shift the bits by n and cast the result to the initial type, i.e.:
* return float(reinterpret_cast<uint>(a) >> n)
*/
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pshiftright_and_cast(Packet a, int n);
/** Default implementation of pfrexp for float.
* It is expected to be called by implementers of template<> pfrexp,
* and the above pshiftright_and_cast function must be implemented.
* It is expected to be called by implementers of template<> pfrexp.
*/
template<typename Packet> EIGEN_STRONG_INLINE Packet
pfrexp_float(const Packet& a, Packet& exponent) {
const Packet cst_126f = pset1<Packet>(126.0f);
const Packet cst_half = pset1<Packet>(0.5f);
const Packet cst_inv_mant_mask = pset1frombits<Packet>(~0x7f800000u);
exponent = psub(pshiftright_and_cast(a,23), cst_126f);
return por(pand(a, cst_inv_mant_mask), cst_half);
}
/** \internal shift the bits by n and cast the result to the initial type, i.e.:
* return reinterpret_cast<float>(int(a) >> n)
*/
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pcast_and_shiftleft(Packet a, int n);
pfrexp_float(const Packet& a, Packet& exponent);
/** Default implementation of pldexp for float.
* It is expected to be called by implementers of template<> pldexp,
* and the above pcast_and_shiftleft function must be implemented.
* It is expected to be called by implementers of template<> pldexp.
*/
template<typename Packet> EIGEN_STRONG_INLINE Packet
pldexp_float(Packet a, Packet exponent) {
const Packet cst_127 = pset1<Packet>(127.f);
// return a * 2^exponent
return pmul(a, pcast_and_shiftleft(padd(exponent, cst_127), 23));
}
pldexp_float(Packet a, Packet exponent);
} // end namespace internal