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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: else ladders practice
Date: Wed, 27 Nov 2024 21:18:09 -0800
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Bart <bc@freeuk.com> writes:

> On 26/11/2024 12:29, Tim Rentsch wrote:
>
>> Bart <bc@freeuk.com> writes:
>>
>>> On 25/11/2024 18:49, Tim Rentsch wrote:
>>>
>>>> Bart <bc@freeuk.com> writes:
>>>>
>>>>> It's funny how nobody seems to care about the speed of compilers
>>>>> (which can vary by 100:1), but for the generated programs, the 2:1
>>>>> speedup you might get by optimising it is vital!
>>>>
>>>> I think most people would rather take this path (these times
>>>> are actual measured times of a recently written program):
>>>>
>>>>       compile time:       1 second
>>>>       program run time:   ~7 hours
>>>>
>>>> than this path (extrapolated using the ratios mentioned above):
>>>>
>>>>       compile time:       0.01 second
>>>>       program run time:   ~14 hours
>>>
>>> I'm trying to think of some computationally intensive app that would
>>> run non-stop for several hours without interaction.
>>
>> The conclusion is the same whether the program run time
>> is 7 hours, 7 minutes, or 7 seconds.
>
> Funny you should mention 7 seconds.  If I'm working on single source
> file called sql.c for example, that's how long it takes for gcc to
> create an unoptimised executable:
>
>   c:\cx>tm gcc sql.c            #250Kloc file
>   TM:  7.38

Your example illustrates my point.  Even 250 thousand lines of
source takes only a few seconds to compile.  Only people nutty
enough to have single source files over 25,000 lines or so --
over 400 pages at 60 lines/page! -- are so obsessed about
compilation speed.  And of course you picked the farthest-most
outlier as your example, grossly misrepresenting any sort of
average or typical case.