From: "H.J. Lu" <hjl.tools@gmail.com>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: Ulrich Weigand <uweigand@de.ibm.com>,
gcc-patches@gcc.gnu.org, GCC Development <gcc@gcc.gnu.org>
Subject: Re: [RFC PATCH, i386]: Allow zero_extended addresses (+ problems with reload and offsetable address, "o" constraint)
Date: Tue, 09 Aug 2011 15:40:00 -0000 [thread overview]
Message-ID: <CAMe9rOpckAAhBKD4RQcTfYo1DjCzv4Dc2cUtzjVuRaAbMh+3GA@mail.gmail.com> (raw)
In-Reply-To: <CAFULd4Y5z6v2DtFCWgdLxDLE3eX-Pd=9iFtWGmJu9tvYOb33rA@mail.gmail.com>
On Tue, Aug 9, 2011 at 12:40 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Mon, Aug 8, 2011 at 7:11 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
>
>>> Moves are special as far as reload is concerned. If there is already
>>> a move instruction present *before* reload, it will get fixed up
>>> according to its constraints as any other instruction.
>>>
>>> However, reload will *introduce* new moves as part of its operation,
>>> and those will *not* themselves get reloaded. Instead, reload simply
>>> assumes that every plain move will just succeed without requiring
>>> any reload; if this is not true, the target *must* provide a
>>> secondary reload for this move.
>>>
>>> (Note that the secondary reload could also work by reloading the
>>> target address into a temporary; that's up to the target to
>>> implement.)
>>
>> Whoa, indeed.
>>
>> Using attached patch that reloads memory address instead of going
>> through XMM register, the code for the testcase improves from:
>
> Committed to mainline with following ChangeLog entry:
>
> 2011-08-09 Uros Bizjak <ubizjak@gmail.com>
>
> PR target/49781
> * config/i386/i386.md (reload_noff_load): New.
> (reload_noff_store): Ditto.
> * config/i386/i386.c (ix86_secondary_reload): Use
> CODE_FOR_reload_noff_load and CODE_FOR_reload_noff_store to handle
> double-word moves from/to non-offsetable addresses instead of
> generating XMM temporary.
>
> Re-bootstrapped and re-tested on x86_64-pc-linux-gnu {,-m32}.
>
No regressions on x32 with GCC, glibc and SPEC CPU 2K/2006.
Thanks.
--
H.J.
prev parent reply other threads:[~2011-08-09 15:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-05 18:51 Uros Bizjak
2011-08-07 12:39 ` Uros Bizjak
2011-08-08 15:30 ` Ulrich Weigand
2011-08-08 17:12 ` Uros Bizjak
2011-08-08 17:14 ` H.J. Lu
2011-08-09 7:41 ` Uros Bizjak
2011-08-09 15:40 ` H.J. Lu [this message]
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