Re: [PATCH v3] Add support for sparc compare-and-branch

[Richard Henderson <rth@redhat.com>]

On 10/22/2012 08:39 PM, David Miller wrote:
> +  /* Compare and Branch is limited to +-2KB.  If it is too far away,
> +     change
> +
> +     cxbne X, Y, .LC30
> +
> +     to
> +
> +     cxbe X, Y, .+12
> +     ba,pt xcc, .LC30
> +      nop  */

Based on your no-control-after cbcond comment at the top
of the patch, surely this should contain another nop as well.

> +  *p++ = '\t';
> +  *p++ = '%';
> +  *p++ = '1';
> +  *p++ = ',';
> +  *p++ = ' ';
> +  *p++ = '%';
> +  *p++ = '2';
> +  *p++ = ',';
> +  *p++ = ' ';

And surely all this code isn't so performance sensitive that
it needs to be written in such an unreadable way.

  p = stpcpy (p, "\t%1, %2, ");

is at least a little better.

Though really there's just 3 variable portions of the pattern, so
I wonder if a lesser number of snprintf calls might be good enough.

  if (far)
    {
      if (veryfar)
        snprintf (buf, sizeof(buf), "c%cb%s\t%%1, %%2, .+16\n\t"
		  "b\t%%l3\n\t nop", size_char, cond_str);
      else
        snprintf (buf, sizeof(buf), "c%cb%s\t%%1, %%2, .+16\n\t"
		  "ba,pt\t%%xcc,%%l3\n\t nop", size_char, cond_str);
    }
  else
    snprintf (buf, sizeof(buf), "c%cb%s\t%%1, %%2, %%l3", size_char, cond_str);


r~