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Re: [RFC PATCH, i386]: Allow zero_extended addresses (+ problems with reload and offsetable address, "o" constraint)
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.