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Re: GAS .fpu directive
- From: Renato Golin <renato dot golin at linaro dot org>
- To: Peter Bergner <bergner at vnet dot ibm dot com>
- Cc: Richard Earnshaw <rearnsha at arm dot com>, Nicholas Clifton <nickc at redhat dot com>, "binutils at sourceware dot org" <binutils at sourceware dot org>
- Date: Wed, 20 Aug 2014 19:02:28 +0100
- Subject: Re: GAS .fpu directive
- Authentication-results: sourceware.org; auth=none
- References: <CAMSE1keWd0+uUS0fpaC3-yXsnN-z2_Bsa5anwvQAQwXgWuw_Yw at mail dot gmail dot com> <53F4C261 dot 8090900 at redhat dot com> <53F4CB31 dot 9080701 at arm dot com> <1408553484 dot 5894 dot 8 dot camel at otta>
On 20 August 2014 17:51, Peter Bergner <bergner@vnet.ibm.com> wrote:
> I also forgot about GCC's function specific optimization support
> which would require this:
>
> https://gcc.gnu.org/wiki/FunctionSpecificOpt
So, ARCH, CPU and FPU options are not monotonic crescent (ex. this is
not necessarily true in all contexts: a7 < a8 < a9 < a15) and extra
flags (like +neon, +crypto, +d16) make it a multi-axis vector space.
How do you choose the value for the appropriate build attributes in
this case and avoid linking unsupported libraries?
Maybe Intel's cores and SSE/AVX is indeed sequentially linear in
implementation? Does Intel deprecate anything at all?
Anyway, that's probably much more of an ARM problem than a compiler
problem, and that might, indeed, be the reason why I won't be able to
kill that "feature" in LLVM's IAS. Damn! :)
cheers,
--renato
PS: Should this usage and semantics be documented somewhere in
binutils' wiki/docs?