for (unsigned i = 0; i < num_components; i++) {
nir_alu_instr *chan = nir_alu_instr_create(mem_ctx, chan_op);
nir_alu_ssa_dest_init(chan, 1);
for (unsigned i = 0; i < num_components; i++) {
nir_alu_instr *chan = nir_alu_instr_create(mem_ctx, chan_op);
nir_alu_ssa_dest_init(chan, 1);