topic Re:Enabling FMAs and disabling vectorisation in Intel® oneAPI DPC++/C++ Compiler

Enabling FMAs and disabling vectorisation

MikeSmith1 — Thu, 01 Jun 2023 19:52:38 GMT

I am trying to obtain a version of the code with FMAs enabled and *all* vectorisations disabled. In essence, something that I would obtain with GCC using -mfma and -fno-tree-vectorize.

(I am using a Windows machine).

I notice that /Qfma (-fma) exists to enable FMAs but it must be used alongside a flag specifying the architecture. But that in turn enables vectorisations. I tried switching them off with /Qvec- (-no-vec) but vectorised assembly instructions still get produced. I also tried using /Qno-simd to switch them off, but I get:

icx: command line warning #10430: Unsupported command line options encountered
These options as listed are not supported.
For more information, use '/Qnextgen-diag'.
option list:
/Qsimd-

What is the way to go here? Thank you.

Re:Enabling FMAs and disabling vectorisation

NoorjahanSk_Intel — Tue, 06 Jun 2023 08:54:25 GMT

Hi,

Thanks for posting in Intel Communities.

Could you please provide us with a sample reproducer and steps you have followed so that we can try it from our end?

Also please let us know the compiler version being used along with expected and obtained results.

Thanks & Regards,

Noorjahan.

Re:Enabling FMAs and disabling vectorisation

NoorjahanSk_Intel — Tue, 13 Jun 2023 08:38:05 GMT

Hi,

We haven't heard back from you. Could you please provide an update on your issue?

Thanks & Regards,

Noorjahan.

Re:Enabling FMAs and disabling vectorisation

NoorjahanSk_Intel — Wed, 21 Jun 2023 05:55:15 GMT

Hi,

I have not heard back from you, so I will close this inquiry now. If you need further assistance, please post a new question.

Thanks & Regards,

Noorjahan.