From: Mike Stump <mikestump@comcast.net>
To: Richard Guenther <richard.guenther@gmail.com>
Cc: Jason Merrill <jason@redhat.com>,
Richard Guenther <rguenther@suse.de>,
gcc-patches List <gcc-patches@gcc.gnu.org>, GCC <gcc@gcc.gnu.org>
Subject: Re: Is VIEW_CONVERT_EXPR an lvalue? (was Re: RFA (fold): PATCH for c++/49290 (folding *(T*)(ar+10)))
Date: Mon, 13 Jun 2011 06:12:00 -0000 [thread overview]
Message-ID: <27E63B18-5030-4040-AE79-390ED92868C0@comcast.net> (raw)
In-Reply-To: <BANLkTimPmATmemAUMTD9Ty_=0y1ctx=ZvQ@mail.gmail.com>
On Jun 12, 2011, at 4:03 AM, Richard Guenther wrote:
> Btw, see tree.def which says
>
> /* Represents viewing something of one type as being of a second type.
> This corresponds to an "Unchecked Conversion" in Ada and roughly to
> the idiom *(type2 *)&X in C. The only operand is the value to be
> viewed as being of another type. It is undefined if the type of the
> input and of the expression have different sizes.
>
> This code may also be used within the LHS of a MODIFY_EXPR, in which
> case no actual data motion may occur. TREE_ADDRESSABLE will be set in
> this case and GCC must abort if it could not do the operation without
> generating insns. */
I wasn't able to follow what this was trying to say. :-( No actual data motion may occur? The wording is weasely. Does it mean: Data motion does not occur when used on the LHS of a MODIFY_EXPR? If so, it should just directly state it.
next prev parent reply other threads:[~2011-06-13 2:48 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-07 5:39 RFA (fold): PATCH for c++/49290 (folding *(T*)(ar+10)) Jason Merrill
2011-06-07 10:20 ` Richard Guenther
2011-06-07 10:27 ` Jakub Jelinek
2011-06-07 12:03 ` Richard Guenther
2011-06-07 12:22 ` Richard Guenther
2011-06-07 13:46 ` Michael Matz
2011-06-07 13:49 ` Richard Guenther
2011-06-07 13:55 ` Jason Merrill
2011-06-07 14:05 ` Richard Guenther
2011-06-07 14:24 ` Jason Merrill
2011-06-09 19:47 ` Jason Merrill
2011-06-10 8:53 ` Richard Guenther
2011-06-10 14:03 ` Jason Merrill
2011-06-10 14:20 ` Richard Guenther
2011-06-10 14:32 ` Jason Merrill
2011-06-10 14:34 ` Richard Guenther
2011-06-10 14:45 ` Jason Merrill
2011-06-11 18:24 ` Mike Stump
2011-06-12 11:03 ` Richard Guenther
2011-06-13 7:29 ` Mike Stump
2011-06-13 12:46 ` Richard Guenther
2011-06-14 20:31 ` Mike Stump
2011-06-15 9:54 ` Richard Guenther
2011-06-15 18:57 ` Mike Stump
2011-06-16 7:39 ` Richard Guenther
2011-06-17 14:17 ` Michael Matz
2011-06-20 10:24 ` Richard Guenther
2011-06-12 7:58 ` Is VIEW_CONVERT_EXPR an lvalue? (was Re: RFA (fold): PATCH for c++/49290 (folding *(T*)(ar+10))) Jason Merrill
2011-06-12 13:18 ` Richard Guenther
2011-06-12 13:22 ` Richard Guenther
2011-06-13 6:12 ` Mike Stump [this message]
2011-06-12 22:42 ` Jason Merrill
2011-06-13 12:44 ` Richard Guenther
2011-06-13 17:59 ` RFA (fold): PATCH for c++/49290 (folding *(T*)(ar+10)) Jason Merrill
2011-06-14 9:10 ` Richard Guenther
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