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Groups > comp.lang.c > #106058
| From | BartC <bc@freeuk.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: C Compilers QoI |
| Date | 2017-03-14 17:08 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <oa97tk$dnq$1@dont-email.me> (permalink) |
| References | <oa8pdp$nok$1@dont-email.me> <f0ed403e-ba17-4885-8021-bcf46d4d2baa@googlegroups.com> |
On 14/03/2017 16:35, already5chosen@yahoo.com wrote:
> On Tuesday, March 14, 2017 at 3:01:34 PM UTC+2, Bart wrote:
>> I was doing some very routine tests but came across surprising issues
>> with a few of my C compilers that I didn't expect.
>>
>> This was the test code:
>>
>> int main(void) {
>> int a,b,c,d;
>>
>> a = b+c*d;
>> }
>>
>> except that the 'a=b+c*d;' line was repeated a million times. (Also
>> those lines are in an include file, but I don't think that matters.)
>>
>
> 'gcc -O0' indeed behaves similarly to your description.
> On the other had 'gcc -O1' completed the test in 12.3 sec with peak memory consumption of ~1.6 GB. 'gcc -O2' is similar to -O1.
What was the size of the output?
>> And Tiny C still did it effortlessly in one second!
>
> Most likely, Tiny C does dead code elimination early in the processing chain.
> Please, examine the size of the resulting executive.
Tiny C produced an object file of 11,000,000 bytes in one second.
gcc -O3 completed (in 7 seconds), but produced an object file of 650 bytes.
It's gcc that must be doing dead code elimination early on.
I think a better test is if each line is in its own function. But then
that brings in other issues (eg. hash table conflicts due to hundreds of
thousands of very similar function names, or having to create hundreds
of thousands of random names, and having processing time dominated by
function-handling code rather than expressions).
--
bartc
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C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 13:01 +0000
Re: C Compilers QoI mark.bluemel@gmail.com - 2017-03-14 06:16 -0700
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-14 06:42 -0700
Re: C Compilers QoI "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-03-14 06:56 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 15:58 +0000
Re: C Compilers QoI "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-03-14 09:22 -0700
Re: C Compilers QoI scott@slp53.sl.home (Scott Lurndal) - 2017-03-14 16:54 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-14 10:24 -0700
Re: C Compilers QoI scott@slp53.sl.home (Scott Lurndal) - 2017-03-14 17:58 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-14 14:12 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-14 16:34 -0500
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-14 17:36 -0500
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 23:06 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-14 16:20 -0700
Re: C Compilers QoI antispam@math.uni.wroc.pl - 2017-03-15 02:32 +0000
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-15 12:49 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-15 11:56 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-15 23:09 +0000
Re: C Compilers QoI scott@slp53.sl.home (Scott Lurndal) - 2017-03-16 18:17 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-16 11:47 -0700
Re: C Compilers QoI Ian Collins <ian-news@hotmail.com> - 2017-03-17 07:50 +1300
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-16 12:59 -0700
Re: C Compilers QoI David Brown <david.brown@hesbynett.no> - 2017-03-16 21:24 +0100
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-16 14:23 -0700
Re: C Compilers QoI Ian Collins <ian-news@hotmail.com> - 2017-03-17 11:30 +1300
Re: C Compilers QoI Ian Collins <ian-news@hotmail.com> - 2017-03-17 11:38 +1300
Re: C Compilers QoI Gareth Owen <gwowen@gmail.com> - 2017-03-17 05:07 +0000
Re: C Compilers QoI Ian Collins <ian-news@hotmail.com> - 2017-03-17 20:26 +1300
Re: C Compilers QoI Gareth Owen <gwowen@gmail.com> - 2017-03-17 07:59 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-16 16:14 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-16 22:54 -0500
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-17 09:01 -0700
Re: C Compilers QoI Ian Collins <ian-news@hotmail.com> - 2017-03-26 14:16 +1300
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-26 14:19 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-26 22:43 +0100
Re: C Compilers QoI GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-03-27 01:28 +0200
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-26 22:07 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-27 11:28 +0100
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-27 07:38 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-27 16:23 +0100
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-27 08:55 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-27 17:01 +0100
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-27 10:03 -0700
Re: C Compilers QoI GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-03-27 17:58 +0200
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-27 03:54 -0700
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-27 08:46 -0700
Re: C Compilers QoI scott@slp53.sl.home (Scott Lurndal) - 2017-03-27 17:47 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-27 11:48 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-27 15:37 -0500
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-27 14:46 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-27 20:28 -0500
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-28 01:18 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-28 18:24 -0500
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-29 07:40 -0700
Re: C Compilers QoI David Brown <david.brown@hesbynett.no> - 2017-03-29 17:05 +0200
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-29 11:07 -0700
Re: C Compilers QoI antispam@math.uni.wroc.pl - 2017-03-31 04:04 +0000
Re: C Compilers QoI bartc <bc@freeuk.com> - 2017-03-31 10:53 +0100
Re: C Compilers QoI Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-03-31 07:35 -0700
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-31 08:07 -0700
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-31 07:54 -0700
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-31 07:43 -0700
Re: C Compilers QoI Ian Collins <ian-news@hotmail.com> - 2017-03-17 11:21 +1300
Re: C Compilers QoI Ian Collins <ian-news@hotmail.com> - 2017-03-17 11:24 +1300
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-16 22:15 +0000
Re: C Compilers QoI scott@slp53.sl.home (Scott Lurndal) - 2017-03-17 12:31 +0000
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-16 15:24 -0700
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-16 16:03 -0700
Re: C Compilers QoI scott@slp53.sl.home (Scott Lurndal) - 2017-03-17 12:39 +0000
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-17 08:27 -0700
Re: C Compilers QoI antispam@math.uni.wroc.pl - 2017-03-16 01:35 +0000
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-16 02:18 +0000
Re: C Compilers QoI antispam@math.uni.wroc.pl - 2017-03-18 00:45 +0000
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-18 13:12 +0000
Re: C Compilers QoI antispam@math.uni.wroc.pl - 2017-03-18 20:31 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-18 17:31 -0700
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-16 09:22 -0700
Re: C Compilers QoI Nick Bowler <nbowler@draconx.ca> - 2017-03-24 16:13 +0000
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-24 12:32 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-24 22:13 -0500
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-25 13:05 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-27 15:44 -0500
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-27 14:51 -0700
Re: C Compilers QoI Robert Wessel <robertwessel2@yahoo.com> - 2017-03-27 20:31 -0500
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 17:26 +0000
Re: C Compilers QoI Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-03-15 12:02 -0500
Re: C Compilers QoI David Brown <david.brown@hesbynett.no> - 2017-03-14 15:00 +0100
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-14 07:36 -0700
Re: C Compilers QoI David Brown <david.brown@hesbynett.no> - 2017-03-14 15:57 +0100
Re: C Compilers QoI Andrey Tarasevich <andreytarasevich@hotmail.com> - 2017-03-14 08:11 -0700
Re: C Compilers QoI BGB <cr88192@hotmail.com> - 2017-03-29 23:51 -0500
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 15:28 +0000
Re: C Compilers QoI David Brown <david.brown@hesbynett.no> - 2017-03-14 21:41 +0100
Re: C Compilers QoI Keith Thompson <kst-u@mib.org> - 2017-03-14 09:26 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 18:23 +0000
Re: C Compilers QoI Keith Thompson <kst-u@mib.org> - 2017-03-14 12:05 -0700
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-14 09:35 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 17:08 +0000
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-14 10:24 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 17:34 +0000
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-14 11:55 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 19:03 +0000
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 19:06 +0000
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-14 12:10 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 21:14 +0000
Re: C Compilers QoI already5chosen@yahoo.com - 2017-03-14 14:42 -0700
Re: C Compilers QoI supercat@casperkitty.com - 2017-03-14 14:53 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 23:20 +0000
Re: C Compilers QoI antispam@math.uni.wroc.pl - 2017-03-15 02:43 +0000
Re: C Compilers QoI jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-14 19:39 +0100
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-14 19:10 +0000
Re: C Compilers QoI antispam@math.uni.wroc.pl - 2017-03-14 19:29 +0000
Re: C Compilers QoI Noob <root@127.0.0.1> - 2017-03-15 09:27 +0100
Re: C Compilers QoI ed_davis2@yahoo.com - 2017-03-16 15:10 -0700
Re: C Compilers QoI BartC <bc@freeuk.com> - 2017-03-16 23:19 +0000
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