From: Jeff Law <law@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Alexandre Oliva <aoliva@redhat.com>, GCC <gcc@gcc.gnu.org>
Subject: Re: VTA/debugging vs reload-v2
Date: Tue, 06 Apr 2010 15:23:00 -0000 [thread overview]
Message-ID: <4BBB51DD.2000001@redhat.com> (raw)
In-Reply-To: <20100406063558.GL3601@sunsite.ms.mff.cuni.cz>
On 04/06/10 00:35, Jakub Jelinek wrote:
> On Mon, Apr 05, 2010 at 05:18:35PM -0600, Jeff Law wrote:
>
>>> 2. When renaming references from P to P' in a region, do take debug
>>> insns in the region into account, renaming references in debug insns as
>>> you would in any other insn.
>>>
>>>
>> OK. So presumably the 2nd argument in a VAR_LOCATION can be any rtl
>> expression? Meaning I have to parse it looking for things that need
>> changing? Right?
>>
> The problematic stuff is mainly when some RTL
> with non-VOIDmode (REG, MEM etc.) needs to be replaced with a VOIDmode
> constant - in that case simplify_replace_{,fn_}rtx needs to be used to
> change the invalid RTL into valid.
These shouldn't be a problem.
> But I guess for reload2 you'll be
> changing just REGs and MEMs to other REGs and MEMs - in that case
> just a replacement through say for_each_rtx is possible too.
>
Yea, we're going to have to walk down the expression with for_each_rtx
searching for REGs, then see if the REG we found needs replacing.
Handling narrowing SUBREGs makes this marginally more complex, but it's
still manageable. I just wanted to be sure there that there weren't any
assumptions I could make to simplify the code :-)
jeff
next prev parent reply other threads:[~2010-04-06 15:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-05 16:37 Jeff Law
2010-04-05 20:33 ` Alexandre Oliva
2010-04-05 23:18 ` Jeff Law
2010-04-06 6:36 ` Jakub Jelinek
2010-04-06 15:23 ` Jeff Law [this message]
2010-04-06 15:31 ` Jakub Jelinek
2010-04-07 8:32 ` Alexandre Oliva
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