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Re: Compiler tests

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Compiler tests
Date 2019-01-23 11:11 +0100
Organization A noiseless patient Spider
Message-ID <q29ek9$bom$1@dont-email.me> (permalink)
References (8 earlier) <q24i15$rt2$1@dont-email.me> <q24lat$hnv$1@dont-email.me> <pSl1E.188124$FF1.29988@fx06.am4> <m2sgxmj723.fsf@despina.home> <q29bgo$di0$1@news.albasani.net>

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On 23/01/2019 10:18, BGB wrote:
> On 1/21/2019 10:42 AM, Pascal J. Bourguignon wrote:
>> Bart <bc@freeuk.com> writes:
>>
>>> On 21/01/2019 14:35, David Brown wrote:
>>> Interesting. Something goes wrong with compiling huge numbers of
>>> consecutive assignments, but your reaction is that it is the generator
>>> program that should be changed** instead of the C compiler.
>>>
>>> Of course, some C compilers can cope perfectly well, but you would
>>> still thing the Eiffel program should be changed rather than C
>>> compilers that have trouble?
>>
>> Yes, it is expected that compilers, like any other program, may have
>> limitations.
>>
>> Those limitations may be arbitrary and unjustified (then we could
>> complain I guess), or may be due to technical reasons or other.
>>
>> For example, the size of the generated binary code for a single
>> procedure may be limited, so that jumps use short addressing modes or
>> for other constraints.
>>
> 
> Typically also, multiple passes may be used to figure out (among other
> things), how large of branches are needed.
> 
> For a strong majority of functions, one may be able to get away with
> using branches which have an 8 bit displacement.
> 

Often this is done at the assembler level.  Compilers can have
estimates, which are useful for judging the most efficient code
sequences or layouts to improve code localisation, but the final choice
of displacement sizes can be done by the assembler.

> 
> IME, it is pretty rare to see functions over a few kB, but every so
> often they can get huge (usually in functions containing a "giant switch
> of doom").

Inlining can also lead to large functions.

Then there is the next step - link-time optimisation.  It can also lead
to very large functions as it effectively inlines code across
compilation units.

> 
> Once before, one of my "Giant Switch of Doom" functions managed to cause
> Emscripten to crash, but reported this as a bug and they fixed it.
> 
> 
> In my ISA design, there is currently an effective size limit on
> functions of 1MB (for a 32-bit direct branch op). Going beyond this is
> possible, but the way switch is currently implemented will create
> problems here.

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Compiler tests Bart <bc@freeuk.com> - 2019-01-20 00:03 +0000
  Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-20 16:52 +1300
    Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-20 10:27 +0100
      Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 12:37 +0100
        Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 13:08 +0000
          Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 15:02 +0000
            Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 17:31 +0100
              Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 17:08 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 21:40 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 22:41 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 00:39 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 00:36 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-21 16:33 +1300
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 11:58 +0000
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-21 04:15 -0800
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-22 07:53 +1300
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 01:15 -0600
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 12:00 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-24 08:13 +1300
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 13:30 -0600
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 08:22 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 12:23 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 14:42 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 14:17 +0000
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-21 12:46 -0800
                You guys really, really need to get a room (Was: Compiler tests) gazelle@shell.xmission.com (Kenny McCormack) - 2019-01-24 14:05 +0000
          Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 17:27 +0100
            Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 17:19 +0000
              Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 09:44 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 12:49 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 15:31 +0100
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-21 14:38 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-21 15:15 +0100
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-21 16:05 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 16:39 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-21 12:51 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 00:16 +0000
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-22 08:43 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 12:31 +0000
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-22 17:49 +0100
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-23 11:04 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 11:18 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 15:35 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 15:49 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-21 17:42 +0100
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 03:18 -0600
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 11:11 +0100
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 12:18 -0600
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 13:56 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-22 10:55 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 12:07 +0000
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 04:29 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 12:52 +0000
                Re: Compiler tests mark.bluemel@gmail.com - 2019-01-22 05:04 -0800
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 05:18 -0800
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 05:45 -0800
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 05:35 -0800
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-22 15:10 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 17:30 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-22 23:02 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 23:14 +0000
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-22 15:45 -0800
                Re: Compiler tests Robert Wessel <robertwessel2@yahoo.com> - 2019-01-22 17:57 -0600
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-22 16:36 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 01:37 +0000
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-22 18:53 -0800
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 09:42 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 09:22 +0100
                Re: Compiler tests James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-23 08:52 -0500
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 15:13 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 14:33 +0000
                Re: Compiler tests James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-23 07:30 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 16:05 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 17:17 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 16:29 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 22:04 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 21:50 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 10:45 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 11:55 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 13:58 +0100
                Re: Compiler tests mark.bluemel@gmail.com - 2019-01-24 05:07 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 14:10 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 14:18 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 15:51 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 15:44 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 17:32 +0000
                Re: Compiler tests scott@slp53.sl.home (Scott Lurndal) - 2019-01-24 19:07 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 20:14 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 22:24 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 22:46 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-25 12:34 +1300
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 01:01 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-25 14:15 +1300
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 10:05 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 14:51 +0000
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 09:48 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 10:56 +0100
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 12:08 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 13:28 +0100
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 13:33 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 15:38 +0100
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 15:08 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 13:53 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 12:25 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 10:03 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 10:08 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 11:14 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 12:02 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 13:37 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 13:58 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 14:26 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 15:01 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 15:42 +0100
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-25 10:25 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 14:37 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 16:33 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-25 07:44 -0800
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 17:53 +0100
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-25 10:33 -0800
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 20:43 +0100
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-25 12:17 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 18:31 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 20:41 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 21:19 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-26 10:24 +1300
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 22:27 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 22:39 +0000
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 18:46 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 12:43 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 14:37 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 14:19 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 15:47 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-25 07:17 -0800
                Re: Compiler tests Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-02-03 07:28 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-02-03 12:35 +0100
                Re: Compiler tests Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-02-03 21:47 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-02-03 22:57 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-24 06:47 -0800
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-23 20:22 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 22:12 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-23 21:54 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 11:41 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-24 23:17 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 11:11 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 12:04 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 14:05 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 18:40 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 22:36 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 22:15 +0000
                Re: Compiler tests scott@slp53.sl.home (Scott Lurndal) - 2019-01-25 14:48 +0000
                Re: Compiler tests scott@slp53.sl.home (Scott Lurndal) - 2019-01-25 14:46 +0000
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 17:48 +0000
                Re: Compiler tests James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-23 08:23 -0800
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 16:41 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 16:18 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 17:28 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 20:23 +0000
                Re: Compiler tests Robert Wessel <robertwessel2@yahoo.com> - 2019-01-22 17:52 -0600
          Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 20:17 +0000
    Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-21 00:13 -0600

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