Re: (set (reg:SI ) (scratch:SI)) unrecognizable insn

["Kim, Eunchan" <helpbygrace@xxxxxxxxx>]

On Sat, Oct 3, 2009 at 6:03 PM, Kim, Eunchan <helpbygrace@xxxxxxxxx> wrote:
> Hello everyone.
>
> Here is Thanksgiving day. Everyone went to hometown. But still i'm
> porting gcc. :(
>
> anyway, while i'm compiling libgcc, i got a error message.
>
>>>-----------
> ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c: In function
> ‘uw_install_context_1’:
> ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c:1532: error:
> unrecognizable insn:
> (insn 217 80 81 14
> ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c:1503 (set (reg:SI
> 1 r1)
>        (scratch:SI)) -1 (nil))
> ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c:1532: internal
> compiler error: in extract_insn, at recog.c:1990
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <http://gcc.gnu.org/bugs.html> for instructions.
> --------------<<
>
> the statement is memcpy in unwind-dw2.c:1503
>
>>>------------ unwind-dw2.c:1500-1505
>      if (dwarf_reg_size_table[i] == sizeof (_Unwind_Word))
>        {
>          w = (_Unwind_Internal_Ptr) t;
>          memcpy (c, &w, sizeof (_Unwind_Word));
>        }
>      else
> -----------------<<
>
> memcpy is just a function call. so i can not understand why the
> compiler try to set some value into register.
>
> Also, i've known that (scratch:m ) is used with clobber RTL. But
> scratch is used without (clobber ) in the error message.
>
> Do i specify this RTL into machine description file? or... did i write
> something wrong ?
>
> -- Eunchan
>

One interest thing is that same memcpy is called right below it.

>>-------------- unwind-dw2.c:1500-1511
      if (target->by_value[i] && c)
        {
          _Unwind_Word w;
          _Unwind_Ptr p;
          if (dwarf_reg_size_table[i] == sizeof (_Unwind_Word))
            {
              w = (_Unwind_Internal_Ptr) t;
              memcpy (c, &w, sizeof (_Unwind_Word));
            }
          else
            {
              gcc_assert (dwarf_reg_size_table[i] == sizeof (_Unwind_Ptr));
              p = (_Unwind_Internal_Ptr) t;
              memcpy (c, &p, sizeof (_Unwind_Ptr));
            }
        }
------------------------<<

i commented out the error code ( line 1503 ). then, the error is not occured.

_Unwind_Word is __attribute__((__mode__(__unwind_word__))). and
_Unwind_Ptr is __attribute((__mode__(__pointer__))).

t is 'void *' (void pointer). So, in my opinion, the size of
_Unwind_Word and void * are different. But i'm not sure. I can not
find the way to see the size of _Unwind_Word and _Unwind_Ptr.

In addition, I do not know why a instruction RTL is changed to (set
reg scratch) pattern. the original expanded rtl of :1503 is

>>------------------------ unwind-dw2.c.131r.expand
;; memcpy (c, &w, 4)
(insn 78 77 79 ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c:1503
(set (reg:SI 74)
        (plus:SI (reg/f:SI 33 virtual-stack-vars)
            (const_int 4 [0x4]))) -1 (nil))

(insn 79 78 80 ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c:1503
(set (reg:SI 75)
        (mem/c/i:SI (reg:SI 74) [0 w+0 S4 A32])) -1 (nil))

(insn 80 79 81 ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c:1503
(set (mem:BLK (reg/v/f:SI 43 [ c ]) [0 S4 A8])
        (unspec:BLK [
                (reg:SI 75)
                (mem:QI (plus:SI (reg/v/f:SI 43 [ c ])
                        (const_int 3 [0x3])) [0 S1 A8])
            ] 20)) -1 (nil))

(insn 81 80 0 ../../../../sdk/gcc-4.3.3/libgcc/../gcc/unwind-dw2.c:1503
(parallel [
            (set (mem:BLK (reg/v/f:SI 43 [ c ]) [0 S4 A8])
                (unspec:BLK [
                        (reg:SI 75)
                        (mem:QI (reg/v/f:SI 43 [ c ]) [0 S1 A8])
                        (mem:BLK (reg/v/f:SI 43 [ c ]) [0 S4 A8])
                    ] 21))
            (clobber (scratch:SI))
        ]) -1 (nil))
----------------------<<

anyone give me an advice?

-- Eunchan