From: rubini@unipv.it (Alessandro Rubini)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm: nomadik: avoid assigning u32 to bool
Date: Sun, 3 Apr 2011 12:52:46 +0200 [thread overview]
Message-ID: <20110403105246.GA11998@mail.gnudd.com> (raw)
In-Reply-To: <20110403122611.4cca78b9@absol.kitzblitz>
>> Why? There are dozens of places in the kernel where this done, the code
>> generated should be the same, and it's pretty obvious what is being done
>> as it is.
>
> Primarily because we were asked to avoid casts to bool even if
> they are safe.
[I have studied, meanwhile]
Actually the point of Rabin is, I think, that the patch is not needed.
Our "bool" is the C99 "_Bool" type, for which the compiler
automatically converts all non-0 assignments to 1. Even if storage
is still one byte.
IIUC, the point of _Bool is allowing comparisong with "true", while in
general non-0 is considered true if evaluated in a conditional
but may be "!= 1" so "!= true" if compared explicitly.
You can compile a one-liner to check. I used a few more:
_Bool i[10];
int main(void)
{
i[0] = 1;
i[1] = 10;
return i[0];
}
/alessandro
prev parent reply other threads:[~2011-04-03 10:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-01 21:51 [PATCH] arm: nomadik: avoid assigning u32 to bool Nicolas Kaiser
2011-04-02 21:02 ` Linus Walleij
2011-04-02 21:19 ` Alessandro Rubini
2011-04-03 3:58 ` Rabin Vincent
2011-04-03 10:26 ` Nicolas Kaiser
2011-04-03 10:52 ` Alessandro Rubini [this message]
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