Re: PATCH [5/n] X32: Supprot 32bit address

["H.J. Lu" <hjl.tools@gmail.com>]

On Fri, Jul 15, 2011 at 10:18 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Jul 15, 2011 at 9:09 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>> On Fri, Jul 15, 2011 at 6:07 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>
>>>>>> If the first form of the address is not OK (it does not represent the
>>>>>> hardware operation), then it should not enter into the insn stream.
>>>>>> This means, that it should be fixed ("legitimized") to second form by
>>>>>> appropriate function (it looks that LEGITIMIZE_RELOAD_ADDRESS should
>>>>>> fix it, since the incorrect address is generated by IRA/reload). After
>>>>>> this operation, various predicates, based on ix86_decompose_address
>>>>>> will start to work, since they will decompose valid memory addresses.
>>>>>>
>>>>>
>>>>> IRA/.RELOAD isn't prepared to deal with it and it just ICEs.  I opened
>>>>> a few GCC bugs on this.
>>>>>
>>>>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47744
>>>>>
>>>>> is one of them.  That is why I went this route.
>>>>
>>>> Hm, but it crashed in postreload pass since the address was not in the
>>>> legitimate form.  This is exactly what LEGITIMIZE_RELOAD_ADDRESS
>>>> fixes. Did you try to go this route?
>>>>
>>>
>>> It ran into various ICEs like:
>>>
>>> /export/build/gnu/gcc-x32/build-x86_64-linux/gcc/xgcc
>>> -B/export/build/gnu/gcc-x32/build-x86_64-linux/gcc/ -S -o m.s -mx32 -std=gnu99
>>> -O2 -fPIC    m.i
>>> m.i: In function \u2018__kernel_rem_pio2\u2019:
>>> m.i:18:1: error: insn does not satisfy its constraints:
>>> (insn 108 106 186 3 (set (reg:SI 40 r11 [207])
>>>        (plus:SI (plus:SI (mult:SI (reg:SI 1 dx [205])
>>>                    (const_int 8 [0x8]))
>>>                (subreg:SI (plus:DI (reg/f:DI 7 sp)
>>>                        (const_int 208 [0xd0])) 0))
>>>            (const_int -160 [0xffffffffffffff60]))) m.i:3 251 {*lea_1_x32}
>>>     (nil))
>>> m.i:18:1: internal compiler error: in reload_cse_simplify_operands, at
>>> postreload.c:403
>>> Please submit a full bug report,
>>> with preprocessed source if appropriate.
>>> See <http://gcc.gnu.org/bugs.html> for instructions.
>>> make: *** [m.s] Error 1
>>
>> Yes, this is an example from PR I am referring to. Did you try to
>> define LEGITIMIZE_RELOAD_ADDRESS? It is supposed to fix this.
>>
>
> They make things even more complex. ix86_simplify_base_index_disp
> is called after reload is done since we can do this translation safely
> only on hard registers, not on pseudo registers.
>

Hi Uros,

The current implementation  has been tested extensively. I'd like to keep
it ASIS so that we can have a working x32 support.  We will revisit it later:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49765

after we have a working x32 GCC.

Thanks.

-- 
H.J.