From: Uros Bizjak <ubizjak@gmail.com>
To: Ulrich Weigand <uweigand@de.ibm.com>
Cc: gcc-patches@gcc.gnu.org, GCC Development <gcc@gcc.gnu.org>,
"H.J. Lu" <hjl.tools@gmail.com>
Subject: Re: [RFC PATCH, i386]: Allow zero_extended addresses (+ problems with reload and offsetable address, "o" constraint)
Date: Tue, 09 Aug 2011 07:41:00 -0000 [thread overview]
Message-ID: <CAFULd4Y5z6v2DtFCWgdLxDLE3eX-Pd=9iFtWGmJu9tvYOb33rA@mail.gmail.com> (raw)
In-Reply-To: <CAFULd4Y5mie9zBP5TbvFpuDxSwbKpp=n3sh8iyr3UpSfiqiYxQ@mail.gmail.com>
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}.
Uros.
next prev parent reply other threads:[~2011-08-09 7:41 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 [this message]
2011-08-09 15:40 ` H.J. Lu
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