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From: Paul Eggert <eggert@cs.ucla.edu>
To: Siddhesh Poyarekar <siddhesh@sourceware.org>
Cc: fweimer@redhat.com, libc-alpha@sourceware.org, dickey@his.com
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 <4ffe566a-8002-b574-daee-d6927b8ceaef@cs.ucla.edu>
Organization: UCLA Computer Science Department
Subject: Re: [PATCH v3] wcrtomb: Make behavior POSIX compliant
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On 5/12/22 21:56, Paul Eggert wrote:
> Hope you don't mind my bikeshedding.

Better yet, this:

   s[0] = buf[0];
   if (2 <= result && result <= 4)
     {
       s[1] = buf[1];
       memcpy (&s[result - 2], &buf[result - 2], 2);
     }
   else
     memcpy (s, buf, result);

On x86-64 with GCC 12.1 -O2 and a glibc-supplied charmap, this is only 9 
straight-line instructions, counting the compare insn and the 
conditional-branch insn that is never taken.