On Mon, Jun 27, 2011 at 3:25 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Mon, Jun 27, 2011 at 3:19 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> On Mon, Jun 27, 2011 at 3:08 PM, Ulrich Weigand <uweig...@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 The pseudo should have been replaced by the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)
>
This seems to work. Does it make any senses?
Thanks.
--
H.J.
---
diff --git a/gcc/reload.c b/gcc/reload.c
index 3ad46b9..bdc47d3 100644
--- a/gcc/reload.c
+++ b/gcc/reload.c
@@ -6415,6 +6415,26 @@ find_replacement (rtx *loc)
return reloadreg;
}
+ else if (reloadreg
+ && REG_P (reloadreg)
+ && !r->subreg_loc
+ && GET_CODE (*loc) == SUBREG
+ && r->where == &SUBREG_REG (*loc))
+ {
+ int offset;
+
+ if (r->mode != VOIDmode && GET_MODE (reloadreg) != r->mode)
+ reloadreg = gen_rtx_REG (r->mode, REGNO (reloadreg));
+
+ offset = (GET_MODE_SIZE (GET_MODE (reloadreg))
+ - GET_MODE_SIZE (GET_MODE (*loc)));
+
+ if (! BYTES_BIG_ENDIAN)
+ offset = (offset / UNITS_PER_WORD) * UNITS_PER_WORD;
+ else if (! WORDS_BIG_ENDIAN)
+ offset %= UNITS_PER_WORD;
+ return gen_rtx_SUBREG (GET_MODE (*loc), reloadreg, offset);
+ }
else if (reloadreg && r->subreg_loc == loc)
{
/* RELOADREG must be either a REG or a SUBREG.
