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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: C23 thoughts and opinions
Date: Mon, 03 Jun 2024 13:29:25 -0700
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Lew Pitcher <lew.pitcher@digitalfreehold.ca> writes:

> On Sun, 02 Jun 2024 13:24:23 +0000, Kenny McCormack wrote:
>
>> In article <v3gou9$36n61$3@dont-email.me>,
>> Lawrence D'Oliveiro  <ldo@nz.invalid> wrote:
>>
>>> On Fri, 31 May 2024 17:55:13 -0500, Lynn McGuire wrote:
>>>
>>>>     while (1)
>>>
>>> Why not
>>>
>>>    while (true)
>>>
>>> or even
>>>
>>>    for (;;)
>>>
>>> ?
>
> I've always considered
>   for (;;)
> preferable over
>   while (1)
> as the for (;;) expression does not require the compiler to expand
> and evaluate a condition expression.
>
> For the for (;;), the compiler sees the token stream <LPAREN>
> <SEMICOLON> <SEMICOLON> <RPAREN>, and emits a closed loop, but
> with while (1), the compiler sees <LPAREN> <CONSTANT> <RPAREN>,

But the 'for (;;)' tokens need to be matched to a much more
complicated syntax, with three optional expression (one of
which might be a declaration) before assigning semantics.
There is actually a lot more to do when 'for (;;)' is used.

> and has to evaluate (either at compile time or at execution
> time) the value of the <CONSTANT> to determine whether or or
> not to emit the closed loop logic.

Both gcc and clang turn 'while (1)' into simple loops even
under -O0.  So it can't be that hard.