Finding AVX instructions always fails at cmake configure step

[blais...@gmail.com]

Dear all, 

Hope you are well.

I have tried a few ways to enable AVX instructions (which I think my 12th Gen Intel(R) Core(TM) i9-12900K) should support, yet I am always unable to do so. At the Cmake configuration step, the AVX steps all fails whereas the SSE ones succeed.

How can I remedy this issue?

Best

Bruno

[Martin Kronbichler]

Dear Bruno,

You need to specify appropriate CXX flags. For example, I always use
  -D CMAKE_CXX_FLAGS="-march=native"
on my local machines (that run the code I'm compiling) or
  -D CMAKE_CXX_FLAGS="-march=icelake-server"
on clusters to be sure the right code gets generated. For example GCC lists the available architectures to specify here:

https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html

Best,
Martin

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[blais...@gmail.com]

Dear Martin,

Now I feel kind off dumb. This is what I was doing to compile an AVX test on the side, did not think to include it this way in the CMAKE procedure.

Thanks! Worked very well and now it detects my AVX2 instructions :).

Best

Bruno