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Re: Should we compile x86-64 ld.so with -mno-sse -mno-sse?
- From: "Carlos O'Donell" <carlos at systemhalted dot org>
- To: Andreas Jaeger <aj at suse dot com>
- Cc: libc-alpha at sourceware dot org, "H.J. Lu" <hjl dot tools at gmail dot com>
- Date: Wed, 31 Oct 2012 12:10:11 -0400
- Subject: Re: Should we compile x86-64 ld.so with -mno-sse -mno-sse?
- References: <20121031132245.GA2117@gmail.com><2353366.qlHrN9GaAk@byrd>
On Wed, Oct 31, 2012 at 9:28 AM, Andreas Jaeger <aj@suse.com> wrote:
> On Wednesday, October 31, 2012 06:22:45 H.J. Lu wrote:
>> Hi,
>>
>> Since we don't pass -mno-sse -mno-sse to GCC when compiling ld.so,
>
> Twice -mno-sse?
>
>> GCC is free to use SSE/AVX instructions. I saw 2 SSE instructions
>> in ld.so when compiling x32 glibc with GCC 4.8 -maddress-mode=long.
>
> The usage is fine from an ABI point of view - but I agree, it's a
> question of optimization that we might not want to touch the SSE unit at
> all.
>
> But we're using in general SSE in the routines, so that I don't think
> this is worth it,
What use case is there for not wanting to touch SEE in ld.so?
Cheers,
Carlos.