The goal of this MR is to implement a generic SIMD backend (packet ops) for Eigen that uses clang vector extensions instead of platform-dependent intrinsics. Ideally, this should make it possible to build Eigen and achieve reasonable speed on any platform that has a recent clang compiler, without having to write any inline assembly or intrinsics.
Caveats:
* The current implementation is a proof of concept and supports vectorization for float, double, int32_t, and int64_t using fixed-size 512-bit vectors (a somewhat arbitrary choice). I have not done much to tune this for speed yet.
* For now, there is no way to enable this other than setting -DEIGEN_VECTORIZE_GENERIC on the command line.
* This only compiles with newer versions of clang. I have tested that it compiles and all tests pass with clang 19.1.7.
https://clang.llvm.org/docs/LanguageExtensions.html#vectors-and-extended-vectorsCloses#2998 and #2997
See merge request libeigen/eigen!2051
Co-authored-by: Rasmus Munk Larsen <rmlarsen@google.com>
Co-authored-by: Antonio Sánchez <cantonios@google.com>
This implements `Eigen::internal::assume_aligned` to match the API for C++20 standard as best as possible using either `std::assume_aligned` or `__builtin_assume_aligned` if available. If neither is available, the function is a no-op.
The override macro `EIGEN_ASSUME_ALIGNED` was changed to a `EIGEN_DONT_ASSUME_ALIGNED`, which now forces the function to be a no-op.
See merge request libeigen/eigen!2052
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### Description
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Allow user to configure if `free` is allowed at runtime.
Reverts to Eigen 3.4 behavior by default, where `free(...)` is allowed if `EIGEN_RUNTIME_NO_MALLOC` is defined but `set_is_malloc_allowed(true)`. Adds a separate `set_is_free_allowed(...)` to explicitly control use of `std::free`.
### Reference issue
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Fixes#2983.
### Additional information
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Closes#2983
See merge request libeigen/eigen!2047
