Hi Kewen,

在 12/1/22 1:30 PM, Kewen.Lin 写道:
> on 2022/12/1 13:17, Kewen.Lin via Gcc-patches wrote:
>> Hi Jeff,
>>
>> on 2022/12/1 09:36, Jiufu Guo wrote:
>>> Hi,
>>>
>>> This patch just uses sext_hwi to replace the expression like:
>>> ((value & 0xf..f) ^ 0x80..0) - 0x80..0 for rs6000.cc and rs6000.md.
>>>
>>> Bootstrap & regtest pass on ppc64{,le}.
>>> Is this ok for trunk? 
>>
>> You didn't say it clearly but I guessed you have grepped in the whole
>> config/rs6000 directory, right?  I noticed there are still two places
>> using this kind of expression in function constant_generates_xxspltiw,
>> but I assumed it's intentional as their types are not HOST_WIDE_INT.
>>
>> gcc/config/rs6000/rs6000.cc:      short sign_h_word = ((h_word & 0xffff) ^ 0x8000) - 0x8000;
>> gcc/config/rs6000/rs6000.cc:  int sign_word = ((word & 0xffffffff) ^ 0x80000000) - 0x80000000;
>>
> 
> oh, one place in gcc/config/rs6000/predicates.md got missed.
> 
> ./predicates.md-756-{
> ./predicates.md-757-  HOST_WIDE_INT val;
> ...
> ./predicates.md-762-  val = const_vector_elt_as_int (op, elt);
> ./predicates.md:763:  val = ((val & 0xff) ^ 0x80) - 0x80;
> ./predicates.md-764-  return EASY_VECTOR_15_ADD_SELF (val);
> ./predicates.md-765-})
> 
> Do you mind to have a further check?

Good catch, thanks!
I will update the patch to cover this one. Bootstrap and testing.

I would be better to check all files under rs6000/. I just rechecked
with grep -r "^.*0x8.*-.*0x8" for rs6000.  No other place is missed.


BR,
Jeff (Jiufu)


Updated patch as attached(add predicates.md).


> 
> Thanks!
> 
> Kewen