On Wed, Mar 17, 2021 at 11:35:18AM +0800, Xionghu Luo wrote:
> + machine_mode idx_mode = GET_MODE (idx);
> + if (idx_mode != DImode)
> + idx = convert_modes (DImode, idx_mode, idx, 1);
Segher mentioned you can remove the if (idx_mode != DImode) too,
convert_modes has an early if (mode == oldmode) return x;
> +
> + /* idx = idx * width. */
> + rtx tmp = gen_reg_rtx (DImode);
> + emit_insn (gen_muldi3 (tmp, idx, GEN_INT (width)));
And I have to wonder, when rs6000_expand_vector_set_var_p9
uses here a left shift, can't rs6000_expand_vector_set_var_p8
do the same or is there some reason I'm missing?
gen_muldi3 will just emit a multiplication, are you hoping that
combiner or some other pass will optimize it away later (for width 1)
or change the multiplication into left shift otherwise?
Jakub
