From: Dale Johannesen <dalej@apple.com>
To: Daniel Jacobowitz <drow@mvista.com>
Cc: Dale Johannesen <dalej@apple.com>,
Aldy Hernandez <aldyh@redhat.com>,
gcc@gcc.gnu.org
Subject: Re: subreg question
Date: Thu, 13 Dec 2001 13:04:00 -0000 [thread overview]
Message-ID: <EEBA8D7B-F00C-11D5-86F6-003065C86F94@apple.com> (raw)
In-Reply-To: <20011213154352.A31306@nevyn.them.org>
On Thursday, December 13, 2001, at 12:43 PM, Daniel Jacobowitz wrote:
>>>>
>>>> I don't see why not. (C89) 3.3.4 says the cast might produce an
>>>> invalid
>>>> pointer if it's not aligned properly, which is not the case here.
>>>> Other than that I don't find any relevant restriction in the standard.
>>>> What did you have in mind?
>>>> (FWIW, gcc doesn't warn about this even with -pedantic.)
>>>
>>> It's not an invalid pointer. It doesn't alias with Z, though.
>>
>> Why not?
>
> The C standard's aliasing rules. *((float *)&z) is an object of type
> float; double is a different type than float; z is an object of type
> double; *((float *)&z) and z can not alias.
Can you point me to someplace in the standard that says this?
next prev parent reply other threads:[~2001-12-13 21:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-12 18:13 Dale Johannesen
2001-12-13 1:39 ` Jan Hubicka
2001-12-13 10:33 ` Aldy Hernandez
2001-12-13 12:26 ` Dale Johannesen
2001-12-13 12:39 ` Daniel Jacobowitz
2001-12-13 12:45 ` Dale Johannesen
2001-12-13 12:51 ` Daniel Jacobowitz
2001-12-13 13:04 ` Dale Johannesen [this message]
2001-12-13 13:33 ` Daniel Jacobowitz
2001-12-13 13:34 ` Aldy Hernandez
2001-12-13 14:56 ` Richard Henderson
2001-12-13 13:04 ` Aldy Hernandez
2001-12-13 14:57 ` Joe Buck
2008-03-25 14:56 Jan Hoogerbrugge
2008-03-25 15:58 ` Paul Brook
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