* an interface for SYCL buffers to behave as a non-dereferenceable pointer
* an interface for placeholder accessor to behave like a pointer on both host and device
1. Fix buggy pcmp_eq and unit test for half types.
2. Add unit test for pselect and add specializations for SSE 4.1, AVX512, and half types.
3. Get rid of FIXME: Implement faster pnegate for half by XOR'ing with a sign bit mask.
That was hurting users with compilers that would object to proceed with
that:
"""
./Eigen/src/Core/products/GeneralMatrixVector.h:356:10: error: declaration shadows a static data member of 'general_matrix_vector_product<type-parameter-0-0, type-parameter-0-1, type-parameter-0-2, 1, ConjugateLhs, type-parameter-0-4, type-parameter-0-5, ConjugateRhs, Version>' [-Werror,-Wshadow]
LhsPacketSize = Traits::LhsPacketSize,
^
./Eigen/src/Core/products/GeneralMatrixVector.h:307:22: note: previous declaration is here
static const Index LhsPacketSize = Traits::LhsPacketSize;
"""
This fixes compilation issues with RealScalar types that are not implicitly castable from Index (e.g. ceres Jet types).
Reported by Peter Anderson-Sprecher via eMail