From: David Laight <David.Laight@ACULAB.COM>
To: 'Andy Shevchenko' <andy.shevchenko@gmail.com>,
Richard Fitzgerald <rf@opensource.cirrus.com>
Cc: Petr Mladek <pmladek@suse.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Shuah Khan <shuah@kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
"patches@opensource.cirrus.com" <patches@opensource.cirrus.com>
Subject: RE: [PATCH v4 2/4] lib: vsprintf: Fix handling of number field widths in vsscanf
Date: Fri, 5 Feb 2021 15:23:46 +0000 [thread overview]
Message-ID: <82696a371fe447c2b201fc812e5a4560@AcuMS.aculab.com> (raw)
In-Reply-To: <CAHp75VcARyR4YvnWoVk1gnR8v7u_YJPnV0x3Mbe7iLMrvpbSAQ@mail.gmail.com>
From: Andy Shevchenko
> Sent: 05 February 2021 12:51
>
> On Fri, Feb 5, 2021 at 1:35 PM Richard Fitzgerald
> <rf@opensource.cirrus.com> wrote:
> > On 04/02/2021 16:35, Petr Mladek wrote:
> > > On Wed 2021-02-03 21:45:55, Andy Shevchenko wrote:
> > >> On Wed, Feb 03, 2021 at 04:50:07PM +0000, Richard Fitzgerald wrote:
>
> ...
>
> > >>> + for (; max_chars > 0; max_chars--) {
> > >>
> > >> Less fragile is to write
> > >>
> > >> while (max_chars--)
> > >
> > > Except that the original was more obvious at least for me.
> > > I always prefer more readable code when the compiler might do
> > > the optimization easily. But this is my personal taste.
> > > I am fine with both variants.
>
> I *slightly* prefer while-loop *in this case* due to less characters
> to parse to understand the logic.
The two loops are also have different values for 'max_chars'
inside the loop body.
If 'max_chars' is known to be non-zero the do ... while (--max_chars);
loop will probable generate better code.
But there is no accounting for just how odd some decisions gcc
makes are.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2021-02-05 23:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 16:50 [PATCH v4 1/4] lib: vsprintf: scanf: Negative number must have field width > 1 Richard Fitzgerald
2021-02-03 16:50 ` [PATCH v4 2/4] lib: vsprintf: Fix handling of number field widths in vsscanf Richard Fitzgerald
2021-02-03 19:45 ` Andy Shevchenko
2021-02-04 16:35 ` Petr Mladek
2021-02-05 11:28 ` Richard Fitzgerald
2021-02-05 12:50 ` Andy Shevchenko
2021-02-05 15:23 ` David Laight [this message]
2021-02-05 15:53 ` Andy Shevchenko
2021-02-08 17:56 ` Petr Mladek
2021-02-08 11:47 ` Richard Fitzgerald
2021-02-03 16:50 ` [PATCH v4 3/4] lib: test_scanf: Add tests for sscanf number conversion Richard Fitzgerald
2021-02-03 19:47 ` Andy Shevchenko
2021-02-03 16:50 ` [PATCH v4 4/4] selftests: lib: Add wrapper script for test_scanf Richard Fitzgerald
2021-02-03 19:48 ` Andy Shevchenko
2021-02-03 19:48 ` [PATCH v4 1/4] lib: vsprintf: scanf: Negative number must have field width > 1 Andy Shevchenko
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