Re: PATCH [10/n]: Prepare x32: PR rtl-optimization/49114: Reload failed to handle (set reg:X (plus:X (subreg:X (reg:Y) 0) (const

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

On Tue, Jun 28, 2011 at 8:19 AM, Ulrich Weigand <uweigand@de.ibm.com> wrote:
> H.J. Lu wrote:
>> > it doesn't work;
>> >
>> > allocation.f: In function 'allocation':
>> > allocation.f:1048:0: internal compiler error: in subreg_get_info, at
>> > rtlanal.c:3235
>> > Please submit a full bug report,
>> > with preprocessed source if appropriate.
>> > See <http://gcc.gnu.org/bugs.html> for instructions.
>
>> > since subreg_regno_offset only works on hard registers.
>
> Hmm, OK. ?That look like another latent bug in the original code ...
>
>> + ? ? ? ? if (r->mode != VOIDmode && GET_MODE (reloadreg) != r->mode)
>> + ? ? ? ? ? reloadreg = gen_rtx_REG (r->mode, REGNO (reloadreg));
>
> (As an aside, this is wrong; it's already wrong in the place where you
> copied it from. ?This should now use reload_adjust_reg_for_mode just
> like subst_reload does.)
>
>> +
>> + ? ? ? ? if ((WORDS_BIG_ENDIAN || BYTES_BIG_ENDIAN)
>> + ? ? ? ? ? ? && GET_MODE_SIZE (Pmode) > GET_MODE_SIZE (ptr_mode))
>> + ? ? ? ? ? {
>> + ? ? ? ? ? ? offset = GET_MODE_SIZE (Pmode) - GET_MODE_SIZE (ptr_mode);
>> + ? ? ? ? ? ? if (! BYTES_BIG_ENDIAN)
>> + ? ? ? ? ? ? ? offset = (offset / UNITS_PER_WORD) * UNITS_PER_WORD;
>> + ? ? ? ? ? ? else if (! WORDS_BIG_ENDIAN)
>> + ? ? ? ? ? ? ? offset %= UNITS_PER_WORD;
>> + ? ? ? ? ? }
>> + ? ? ? ? ?else
>> + ? ? ? ? ? ?offset = 0;
>> +
>> + ? ? ? ? return gen_rtx_SUBREG (ptr_mode, reloadreg, offset);
>>
>> works for me.
>
> This doesn't seem correct either, it completely ignores the SUBREG_BYTE
> of the original SUBREG ... ? Also, I don't quite see why this should
> have anything special for Pmode / ptr_mode.
>
> It seems simplest to just use simplify_gen_subreg here. ?Can you try
> the following version?
>
> Thanks,
> Ulrich
>
>
> ChangeLog:
>
> ? ? ? ?* reload.c (struct replacement): Remove SUBREG_LOC member.
> ? ? ? ?(push_reload): Do not set it.
> ? ? ? ?(push_replacement): Likewise.
> ? ? ? ?(subst_reload): Remove dead code.
> ? ? ? ?(copy_replacements): Remove assertion.
> ? ? ? ?(copy_replacements_1): Do not handle SUBREG_LOC.
> ? ? ? ?(move_replacements): Likewise.
> ? ? ? ?(find_replacement): Remove dead code. ?Use reload_adjust_reg_for_mode.
> ? ? ? ?Detect subregs via recursive descent instead of via SUBREG_LOC.
>
>

It works much better.  I am testing it now.

Thanks.

-- 
H.J.