Re: [PATCH 13/13 ver 3] rs6000, remove vector set and vector init built-ins.

[Carl Love <cel@linux.ibm.com>]

Kewen:

On 6/3/24 22:59, Kewen.Lin wrote:
> Hi,
> 
> on 2024/5/30 00:16, Carl Love wrote:
>> This was patch 13 from the previous series.  Note the previous series patch 12 was dropped.  This patch is the same as the previous version.  The additional work to remove  __builtin_vec_set_v1ti, __builtin_vec_set_v2di,  __builtin_vec_set_v2d per the feedback comments with equivalent gimple code is being deferred to a future patch.  The goal of this series was simply to remove duplicated built-ins, extending overloaded built-ins as needed.  Adding the needed gimple code to remove the additional built-ins is beyond the goal of this patch series.
>>
>>                              Carl 
>> -------------------------------------------------------
>>
>> rs6000, remove vector set and vector init built-ins.
>>
>> The vector init built-ins:
>>
>>   __builtin_vec_init_v16qi, __builtin_vec_init_v8hi,
>>   __builtin_vec_init_v4si, __builtin_vec_init_v4sf,
>>   __builtin_vec_init_v2di, __builtin_vec_init_v2df,
>>   __builtin_vec_set_v1ti
> 
> Typo here, s/__builtin_vec_set_v1ti/__builtin_vec_init_v1ti/

Fixed.

> 
>>
>> perform the same operation as initializing the vector in C code.  For
>> example:
>>
>>   result_v4si = __builtin_vec_init_v4si (1, 2, 3, 4);
>>   result_v4si = {1, 2, 3, 4};
>>
>> These two constructs were tested and verified they generate identical
>> assembly instructions with no optimization and -O3 optimization.
>>
>> The vector set built-ins:
>>
>>   __builtin_vec_set_v16qi, __builtin_vec_set_v8hi.
>>   __builtin_vec_set_v4si, __builtin_vec_set_v4sf
> 
> Please also add the reserved ones (...v1ti/v2di/v2df), as they are the 
> same too, temporarily reserving them for the uses in resolve_vec_insert()
> doesn't affect this.

Added the three additional built-ins to the list.

> 
>>
>> perform the same operation as setting a specific element in the vector in
>> C code.  For example:
>>
>>   src_v4si = __builtin_vec_set_v4si (src_v4si, int_val, index);
>>   src_v4si[index] = int_val;
>>
>> The built-in actually generates more instructions than the inline C code
>> with no optimization but is identical with -O3 optimizations.
>>
>> All of the above built-ins that are removed do not have test cases and
>> are not documented.
>>
>> Built-ins   __builtin_vec_set_v1ti __builtin_vec_set_v2di,
>> __builtin_vec_set_v2df are not removed as they are used in function
>> resolve_vec_insert() in file rs6000-c.cc.
>>
>> The built-ins are removed as they don't provide any benefit over just
>> using C code.
>>
>> gcc/ChangeLog:
>> 	* config/rs6000/rs6000-builtins.def (__builtin_vec_init_v16qi,
>> 	__builtin_vec_init_v8hi, __builtin_vec_init_v4si,
>> 	__builtin_vec_init_v4sf, __builtin_vec_init_v2di,
>> 	__builtin_vec_init_v2df, __builtin_vec_set_v1ti,
> 
> Typo, s/__builtin_vec_set_v1ti/__builtin_vec_init_v1ti/

Fixed

> 
>> 	__builtin_vec_set_v16qi, __builtin_vec_set_v8hi.
>> 	__builtin_vec_set_v4si, __builtin_vec_set_v4sf,
>> 	__builtin_vec_set_v2di, __builtin_vec_set_v2df,
>> 	__builtin_vec_set_v1ti): Remove built-in definitions.
> 
> The last three ones are not actually removed.

OK, fixed.

> 
>> ---
>>  gcc/config/rs6000/rs6000-builtins.def | 42 ++-------------------------
>>  1 file changed, 2 insertions(+), 40 deletions(-)
>>
>> diff --git a/gcc/config/rs6000/rs6000-builtins.def b/gcc/config/rs6000/rs6000-builtins.def
>> index 48ebc018a8d..8349d45169f 100644
>> --- a/gcc/config/rs6000/rs6000-builtins.def
>> +++ b/gcc/config/rs6000/rs6000-builtins.def
>> @@ -1118,37 +1118,6 @@
>>    const signed short __builtin_vec_ext_v8hi (vss, signed int);
>>      VEC_EXT_V8HI nothing {extract}
>>  
>> -  const vsc __builtin_vec_init_v16qi (signed char, signed char, signed char, \
>> -            signed char, signed char, signed char, signed char, signed char, \
>> -            signed char, signed char, signed char, signed char, signed char, \
>> -            signed char, signed char, signed char);
>> -    VEC_INIT_V16QI nothing {init}
>> -
>> -  const vf __builtin_vec_init_v4sf (float, float, float, float);
>> -    VEC_INIT_V4SF nothing {init}
>> -
>> -  const vsi __builtin_vec_init_v4si (signed int, signed int, signed int, \
>> -                                     signed int);
>> -    VEC_INIT_V4SI nothing {init}
>> -
>> -  const vss __builtin_vec_init_v8hi (signed short, signed short, signed short,\
>> -             signed short, signed short, signed short, signed short, \
>> -             signed short);
>> -    VEC_INIT_V8HI nothing {init}
>> -
>> -  const vsc __builtin_vec_set_v16qi (vsc, signed char, const int<4>);
>> -    VEC_SET_V16QI nothing {set}
>> -
>> -  const vf __builtin_vec_set_v4sf (vf, float, const int<2>);
>> -    VEC_SET_V4SF nothing {set}
>> -
>> -  const vsi __builtin_vec_set_v4si (vsi, signed int, const int<2>);
>> -    VEC_SET_V4SI nothing {set}
>> -
>> -  const vss __builtin_vec_set_v8hi (vss, signed short, const int<3>);
>> -    VEC_SET_V8HI nothing {set}
>> -
>> -
>>  ; Cell builtins.
>>  [cell]
>>    pure vsc __builtin_altivec_lvlx (signed long, const void *);
>> @@ -1295,15 +1264,8 @@
>>    const signed long long __builtin_vec_ext_v2di (vsll, signed int);
>>      VEC_EXT_V2DI nothing {extract}
>>  
>> -  const vsq __builtin_vec_init_v1ti (signed __int128);
>> -    VEC_INIT_V1TI nothing {init}
>> -
>> -  const vd __builtin_vec_init_v2df (double, double);
>> -    VEC_INIT_V2DF nothing {init}
>> -
>> -  const vsll __builtin_vec_init_v2di (signed long long, signed long long);
>> -    VEC_INIT_V2DI nothing {init}
>> -
>> +;; VEC_SET_V1TI, VEC_SET_V2DF and VEC_SET_V2DI are used in
>> +;; resolve_vec_insert(), rs6000-c.cc
> 
> It would be good to place one TODO here, something like:

Added comment.

> 
> ;; TODO: Remove VEC_SET_V1TI, VEC_SET_V2DF and VEC_SET_V2DI once the uses
> ;; in resolve_vec_insert are replaced by the equivalent gimple statements.
> 
>>    const vsq __builtin_vec_set_v1ti (vsq, signed __int128, const int<0,0>);
>>      VEC_SET_V1TI nothing {set}
>>  
> 
> BR,
> Kewen
>