Cleaning up expand optabs code

[Georg-Johann Lay]

Richard Henderson schrieb:
> On 03/25/2011 05:41 AM, Georg-Johann Lay wrote:
>>> On 03/22/2011 06:48 PM, Richard Henderson wrote:
>>>
>>>> Ok.  Watch out for other target problems this week.
>> libgcc fails to build for avr (SVN 171446)
>>
>> ../../../../../gcc.gnu.org/trunk/libgcc/../gcc/libgcc2.c: In function
>> '__negdi2':
>> ../../../../../gcc.gnu.org/trunk/libgcc/../gcc/libgcc2.c:68:17:
>> internal compiler error: in maybe_gen_insn, at  optabs.c:7123
> 
> This is due to a miscommunication between the middle-end and the backend
> about how many arguments the setmemhi pattern takes.
> 
> (define_expand "setmemhi"
>   [(parallel [(set (match_operand:BLK 0 "memory_operand" "")
>                    (match_operand 2 "const_int_operand" ""))
>               (use (match_operand:HI 1 "const_int_operand" ""))
>               (use (match_operand:HI 3 "const_int_operand" "n"))
>               (clobber (match_scratch:HI 4 ""))
>               (clobber (match_dup 5))])]
> 
> The match_scratch is counted in .n_operands, which makes the count of
> operands not equal 4, so we assume 6 operands are necessary.  We can
> fix this for the special case of avr by only assuming 6 operands when
> there are in fact 6 operands, but of course this could fail just as
> easily if there were two scratches.
> 
> All of which suggests that optional arguments to a named optab is a
> mistake that ought to be rectified.
> 
> I plan to commit the following after bootstrap and check.
> 
> 

Hi, there is still trouble with "setmemhi" on avr, again for the
negdi2 from libgcc:

#1  0x0839ccd7 in maybe_legitimize_operand (icode=CODE_FOR_setmemhi,
opno=4, op=0xbfffd22c) at ../../../gcc.gnu.org/trunk/gcc/optabs.c:7024
(gdb) p *op
$11 = {type = EXPAND_OUTPUT, unsigned_p = 0, unused = 0, mode =
VOIDmode, value = 0xb7d63360}
(gdb) p op->value
$12 = (rtx) 0xb7d63360
(gdb) pr
(use:CC (nil))


i.e. there is garbage in op->value

(gdb)
(gdb) frame 0
#0  fancy_abort (file=0x88099f0
"../../../gcc.gnu.org/trunk/gcc/optabs.c", line=7024,
function=0x880a280 "maybe_legitimize_operand") at
../../../gcc.gnu.org/trunk/gcc/diagnostic.c:893
(gdb)

Sources are as of svn trunk 4.7 (SVN 171773)

Reading specs from /mnt/nfs/home/georg/gnu/build/gcc-4.6-avr/gcc/specs
COLLECT_GCC=/mnt/nfs/home/georg/gnu/build/gcc-4.6-avr/gcc/xgcc
COLLECT_LTO_WRAPPER=/mnt/nfs/home/georg/gnu/build/gcc-4.6-avr/gcc/lto-wrapper
Target: avr
Configured with: ../../gcc.gnu.org/trunk/configure --target=avr
--prefix=/local/gnu/install/gcc-4.6 --enable-languages=c,c++
--disable-libssp --disable-libada --disable-nls --disable-shared

Johann