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Re: Q: What is default architecture for code produced by native compiler
From: |
Eli Zaretskii |
Subject: |
Re: Q: What is default architecture for code produced by native compiler? |
Date: |
Wed, 25 Aug 2021 15:04:17 +0300 |
> Cc: emacs-devel@gnu.org
> Date: Wed, 25 Aug 2021 07:36:59 +0000
> From: Andrea Corallo via "Emacs development discussions."
> <emacs-devel@gnu.org>
>
> > (setq native-comp-driver-options '("-march=native" "-mcpu=native"))
> >
> > but I see no difference in emitted code when I dissaemble produced binaries.
>
> Driver options are not for the compiler but rather linker and assembler,
> infact `native-comp-driver-options' relies on
> 'gcc_jit_context_add_driver_option' [1].
Then the name of the defcustom is misleading, IMO. These can only be
the options that cc1 (or assembler/linker) understands, is that right?
And I guess this means we cannot support GCC options, because there's
no front-end driver like GCC in libgccjit?
> That said for most of the code we generate ATM I doubt would make much
> difference to specify a different -march and/or -mcpu.
That's also my opinion.