Re: [PATCH] rs6000: Expand vec_insert in expander instead of gimple [PR79251]

[luoxhu via Gcc-patches]

On 2020/9/2 17:30, Richard Biener wrote:
>> so maybe bypass convert_vector_to_array_for_subscript for special 
>> circumstance
>> like "i = v[n%4]" or "v[n&3]=i" to generate vec_extract or vec_insert builtin
>> call a relative simpler method?
> I think you have it backward.  You need to work with what
> convert_vector_to_array_for_subscript
> gives and deal with it during RTL expansion / optimization to generate
> more optimal
> code for power.  The goal is to have as little target specific
> builtins during the GIMPLE
> optimization phase (because we cannot work out its semantics in optimizers).

OK, got it, will add optabs vec_insert and expand 
"VIEW_CONVERT_EXPR<int[4]>(v1)[_1] = i_6(D);"
expressions to rs6000_expand_vector_insert instead of builtin call.  
vec_extract already has optabs and "i = v[n%4]" should be in another patch
after this.


Thanks,
Xionghu