Re: [PATCH] rs6000: avoid ineffective replacement of splitters

[Jiufu Guo <guojiufu@linux.ibm.com>]

Hi,

"Kewen.Lin" <linkw@linux.ibm.com> writes:

> Hi Jeff,
>
> on 2022/8/12 14:39, Jiufu Guo via Gcc-patches wrote:
>> Hi,
>> 
>> As a comment in
>> https://gcc.gnu.org/pipermail/gcc-patches/2022-August/599556.html
>> 
>> Those splitters call rs6000_emit_set_const directly, and the replacements
>> are never used.  Using (pc) would be less misleading.
>
> Since the replacements are never used, IMHO this subject doesn't
> quite meet the change.  How about "fix misleading new patterns
> of splitters"?
Thanks for your helpful sugguestion!

BR,
Jeff(Jiufu)
>
>> 
>> This patch pass bootstrap&regtest on ppc64 BE and LE.
>> Is this ok for trunk.
>
> This patch is OK w/ or w/o subject tweaked.  Thanks!
>
> BR,
> Kewen
>
>> 
>> BR,
>> Jeff(Jiufu)
>> 
>> gcc/ChangeLog:
>> 
>> 	* config/rs6000/rs6000.md: (constant splitters): Use "(pc)" as the
>> 	replacements.
>> 
>> ---
>>  gcc/config/rs6000/rs6000.md | 12 +++---------
>>  1 file changed, 3 insertions(+), 9 deletions(-)
>> 
>> diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
>> index 1367a2cb779..7fadbeef1aa 100644
>> --- a/gcc/config/rs6000/rs6000.md
>> +++ b/gcc/config/rs6000/rs6000.md
>> @@ -7727,11 +7727,7 @@ (define_split
>>    [(set (match_operand:SI 0 "gpc_reg_operand")
>>  	(match_operand:SI 1 "const_int_operand"))]
>>    "num_insns_constant (operands[1], SImode) > 1"
>> -  [(set (match_dup 0)
>> -	(match_dup 2))
>> -   (set (match_dup 0)
>> -	(ior:SI (match_dup 0)
>> -		(match_dup 3)))]
>> +  [(pc)]
>>  {
>>    if (rs6000_emit_set_const (operands[0], operands[1]))
>>      DONE;
>> @@ -9662,8 +9658,7 @@ (define_split
>>    [(set (match_operand:DI 0 "int_reg_operand_not_pseudo")
>>  	(match_operand:DI 1 "const_int_operand"))]
>>    "TARGET_POWERPC64 && num_insns_constant (operands[1], DImode) > 1"
>> -  [(set (match_dup 0) (match_dup 2))
>> -   (set (match_dup 0) (plus:DI (match_dup 0) (match_dup 3)))]
>> +  [(pc)]
>>  {
>>    if (rs6000_emit_set_const (operands[0], operands[1]))
>>      DONE;
>> @@ -9675,8 +9670,7 @@ (define_split
>>    [(set (match_operand:DI 0 "int_reg_operand_not_pseudo")
>>  	(match_operand:DI 1 "const_scalar_int_operand"))]
>>    "TARGET_POWERPC64 && num_insns_constant (operands[1], DImode) > 1"
>> -  [(set (match_dup 0) (match_dup 2))
>> -   (set (match_dup 0) (plus:DI (match_dup 0) (match_dup 3)))]
>> +  [(pc)]
>>  {
>>    if (rs6000_emit_set_const (operands[0], operands[1]))
>>      DONE;