[llvm] [LoongArch] Optimize inserting extracted elements (PR #146018)

[via llvm-commits]

tangaac wrote:

> > This change improves vector_insert for lasx
> > ```
> > // XVINSGR2VR_{W/D}
> > def : Pat<(vector_insert v8i32:$xd, GRLenVT:$rj, uimm3:$imm),
> >           (XVINSGR2VR_W v8i32:$xd, GRLenVT:$rj, uimm3:$imm)>;
> > def : Pat<(vector_insert v4i64:$xd, GRLenVT:$rj, uimm2:$imm),
> >           (XVINSGR2VR_D v4i64:$xd, GRLenVT:$rj, uimm2:$imm)>;
> > 
> > def : Pat<(vector_insert v8f32:$vd, FPR32:$fj, uimm3:$imm),
> >           (XVINSGR2VR_W $vd, (COPY_TO_REGCLASS FPR32:$fj, GPR), uimm3:$imm)>;
> > def : Pat<(vector_insert v4f64:$vd, FPR64:$fj, uimm2:$imm),
> >           (XVINSGR2VR_D $vd, (COPY_TO_REGCLASS FPR64:$fj, GPR), uimm2:$imm)>;
> > ```
> > 
> > 
> >     
> >       
> >     
> > 
> >       
> >     
> > 
> >     
> >   
> > -->
> > ```
> > // XVINSGR2VR_{W/D}
> > def : Pat<(vector_insert v8i32:$xd, GRLenVT:$rj, uimm3:$imm),
> >           (XVINSGR2VR_W v8i32:$xd, GRLenVT:$rj, uimm3:$imm)>;
> > def : Pat<(vector_insert v4i64:$xd, GRLenVT:$rj, uimm2:$imm),
> >           (XVINSGR2VR_D v4i64:$xd, GRLenVT:$rj, uimm2:$imm)>;
> > 
> > // XVINSVE0_{W/D}
> > def : Pat<(vector_insert v8f32:$vd, FPR32:$fj, uimm3:$imm),
> >           (XVINSVE0_W $vd, (SUBREG_TO_REG (i64 0), FPR32:$fj, sub_32), uimm3:$imm)>;
> > def : Pat<(vector_insert v4f64:$vd, FPR64:$fj, uimm2:$imm),
> >           (XVINSVE0_D $vd, (SUBREG_TO_REG (i64 0), FPR64:$fj, sub_64), uimm2:$imm)>;
> > ```
> 
> The purpose of this pr is mainly to optimize inserting extracted elements from 128 or 256 bits vector. I think we can do this optimization for `vector_insert` in a later patch.

OK

https://github.com/llvm/llvm-project/pull/146018