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.tools@gmail.com>]

On Mon, Jun 27, 2011 at 3:19 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Mon, Jun 27, 2011 at 3:08 PM, Ulrich Weigand <uweigand@de.ibm.com> wrote:
>> H.J. Lu wrote:
>>
>>> reload generates:
>>>
>>> (insn 914 912 0 (set (reg:SI 0 ax)
>>>         (plus:SI (subreg:SI (reg/v/f:DI 182 [ b ]) 0)
>>>             (const_int 8 [0x8]))) 248 {*lea_1_x32}
>>>      (nil))
>>>
>>> from
>>>
>>> insn = emit_insn_if_valid_for_reload (gen_rtx_SET (VOIDmode, out, in));
>>
>> Interesting.  The pseudo should have been replaced by the
>> hard register (reg:DI 1) during the preceding call to
>>      op0 = find_replacement (&XEXP (in, 0));
>> (since reload 0 should have pushed a replacement record.)
>>
>> Interestingly enough, in the final output that replacement *is*
>> performed in the REG_EQUIV note:
>>
>> (insn 1023 1022 1024 34 (set (reg:SI 1 dx)
>>        (plus:SI (reg:SI 1 dx)
>>            (const_int 8 [0x8]))) spooles.c:291 248 {*lea_1_x32}
>>     (expr_list:REG_EQUIV (plus:SI (subreg:SI (reg:DI 1 dx) 0)
>>            (const_int 8 [0x8]))
>>        (nil)))
>>
>> which is why I hadn't expected this to be a problem here.
>>
>> Can you try to find out why the find_replacement doesn't work
>> with your test case?
>>
>
> I will investigate.  Could (reg:SI 1 dx) vs  (subreg:SI (reg:DI 1 dx) 0)
> a problem?
>

find_replacement never checks subreg:

Breakpoint 3, find_replacement (loc=0x7ffff068ab00)
    at /export/gnu/import/git/gcc-x32/gcc/reload.c:6411
6411	      if (reloadreg && r->where == loc)
(reg:DI 0 ax)
(reg/v/f:DI 182 [ b ])
(gdb) call debug_rtx (*loc)
(subreg:SI (reg/v/f:DI 182 [ b ]) 0)
(gdb)


-- 
H.J.