Option to select ISA at compile-time

[Tirthankar Mazumder]

Hi, I was looking at blaze and was quite impressed by its speed. For this reason, I am hoping I can add blaze as a math backend in the algebra-plugins repository for the ACTS project.

However, the project need the math backend to have cross-compilation support, because it is often the case that the executable is compiled on machine A and then actually run on machine B (which has different ISAs enabled).

From what I could tell by reading the wiki, the blaze config stuff currently only supports enabling/disabling vectorization, but doesn’t allow for fine-grained control of the ISAs enabled. When I tried to manually disable AVX 512, I was unable to do so because the AVX preprocessor macros are used in many places in the code.

[Klaus Iglberger]

Hi Tirthankar!

Thanks for creating this issue. We understand your requirement. However, it is not entirely clear to us why asking for a particular ISA via the according compiler flags (e.g. ‘-msse4.2’, ‘-mavx’, …) is not enough (even for cross-complication).

If you take a look at the file ‘blaze/system/Vectorization.h’ you’ll find the place where all Blaze modes (e.g. ‘BLAZE_AVX_MODE’) are defined. Would these flags give you more fine-grained control of the ISAs?

Best regards,

Klaus!