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Re: [RFC PATCH] Add strcmp, strncmp, memcmp inline implementation.
- From: Alexander Monakov <amonakov at ispras dot ru>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: Ondřej Bílka <neleai at seznam dot cz>, libc-alpha at sourceware dot org
- Date: Thu, 28 May 2015 19:41:55 +0300 (MSK)
- Subject: Re: [RFC PATCH] Add strcmp, strncmp, memcmp inline implementation.
- Authentication-results: sourceware.org; auth=none
- References: <20150525015826 dot GA29445 at domone> <alpine dot DEB dot 2 dot 10 dot 1505281619080 dot 16930 at digraph dot polyomino dot org dot uk>
On Thu, 28 May 2015, Joseph Myers wrote:
> On Mon, 25 May 2015, Ondřej Bílka wrote:
>
> > Hi,
> >
> > I just found that on x64 gcc __builtin_strcmp suck a lot. And by lot I
> > mean its around three times slower than libcall by using rep cmpsb which
> > even intel manual says that shouldn't be used.
>
> GCC bug report number? It's not helpful to say "suck a lot" without
> reporting the issues to the other project (identifying the compiler
> options etc. in use). We need to cooperate appropriately with other free
> software projects in developing glibc.
I think this report should serve well:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43052
Alexander