[PATCH 2/4] Switch other switch expansion methods into classes.

[Steven Bosscher]

On Tue, Jun 12, 2018 at 10:44 PM, Jeff Law wrote:
> On 06/05/2018 01:15 AM, marxin wrote:
>>
>> +     The definition of "much bigger" depends on whether we are
>> +     optimizing for size or for speed.  If the former, the maximum
>> +     ratio range/count = 3, because this was found to be the optimal
>> +     ratio for size on i686-pc-linux-gnu, see PR11823.  The ratio
>> +     10 is much older, and was probably selected after an extensive
>> +     benchmarking investigation on numerous platforms.  Or maybe it
>> +     just made sense to someone at some point in the history of GCC,
>> +     who knows...  */
> "much older" is an understatement.  I believe the magic "10" pre-dates
> my involvement in GCC.  You can find evidence of it as far back as
> gcc-0.9.  I doubt it was extensively benchmarked, and even if it was,
> the targets on which it was benchmarked don't reflect modern target
> reality in terms of importance.

When I added this comment
(https://gcc.gnu.org/viewcvs/gcc/trunk/gcc/stmt.c?r1=189284&r2=189285&)
it as an attempt at humor. I should have turned the number into a
PARAM at the time. Maybe that's something Martin could still do now?

Ciao!
Steven