From 2b2f1f16a04dfba4e02a7f331befb5bd94d4a1be Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Wed, 9 Sep 2015 14:47:28 -0700 Subject: [PATCH] nir/lower_vec_to_movs: Get rid of start_idx and swizzle compacting Previously, we did this thing with keeping track of a separate start_idx which was different from the iteration variable. I think this was a relic of the way that GLSL IR implements writemasks. In NIR, if a given bit in the writemask is unset then that channel is just "unused", not missing. In particular, a vec4 operation with a writemask of 0xd will use sources 0, 2, and 3 and leave source 1 alone. We can simplify things a good deal (and make them correct) by removing this "compacting" step. Reviewed-by: Eduardo Lima Mitev Reviewed-by: Eric Anholt --- src/glsl/nir/nir_lower_vec_to_movs.c | 33 +++++++++++----------------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/src/glsl/nir/nir_lower_vec_to_movs.c b/src/glsl/nir/nir_lower_vec_to_movs.c index 993a1082f96..29dd0ca7235 100644 --- a/src/glsl/nir/nir_lower_vec_to_movs.c +++ b/src/glsl/nir/nir_lower_vec_to_movs.c @@ -53,29 +53,25 @@ src_matches_dest_reg(nir_dest *dest, nir_src *src) * which ones have been processed. */ static unsigned -insert_mov(nir_alu_instr *vec, unsigned start_channel, - unsigned start_src_idx, nir_shader *shader) +insert_mov(nir_alu_instr *vec, unsigned start_idx, nir_shader *shader) { - unsigned src_idx = start_src_idx; - assert(src_idx < nir_op_infos[vec->op].num_inputs); + assert(start_idx < nir_op_infos[vec->op].num_inputs); nir_alu_instr *mov = nir_alu_instr_create(shader, nir_op_imov); - nir_alu_src_copy(&mov->src[0], &vec->src[src_idx], mov); + nir_alu_src_copy(&mov->src[0], &vec->src[start_idx], mov); nir_alu_dest_copy(&mov->dest, &vec->dest, mov); - mov->dest.write_mask = (1u << start_channel); - mov->src[0].swizzle[start_channel] = vec->src[src_idx].swizzle[0]; - src_idx++; + mov->dest.write_mask = (1u << start_idx); + mov->src[0].swizzle[start_idx] = vec->src[start_idx].swizzle[0]; - for (unsigned i = start_channel + 1; i < 4; i++) { + for (unsigned i = start_idx + 1; i < 4; i++) { if (!(vec->dest.write_mask & (1 << i))) continue; - if (nir_srcs_equal(vec->src[src_idx].src, vec->src[start_src_idx].src)) { + if (nir_srcs_equal(vec->src[i].src, vec->src[start_idx].src)) { mov->dest.write_mask |= (1 << i); - mov->src[0].swizzle[i] = vec->src[src_idx].swizzle[0]; + mov->src[0].swizzle[i] = vec->src[i].swizzle[0]; } - src_idx++; } nir_instr_insert_before(&vec->instr, &mov->instr); @@ -121,26 +117,23 @@ lower_vec_to_movs_block(nir_block *block, void *void_impl) * destination reg, in case other values we're populating in the dest * might overwrite them. */ - for (unsigned i = 0, src_idx = 0; i < 4; i++) { + for (unsigned i = 0; i < 4; i++) { if (!(vec->dest.write_mask & (1 << i))) continue; - if (src_matches_dest_reg(&vec->dest.dest, &vec->src[src_idx].src)) { - finished_write_mask |= insert_mov(vec, i, src_idx, shader); + if (src_matches_dest_reg(&vec->dest.dest, &vec->src[i].src)) { + finished_write_mask |= insert_mov(vec, i, shader); break; } - src_idx++; } /* Now, emit MOVs for all the other src channels. */ - for (unsigned i = 0, src_idx = 0; i < 4; i++) { + for (unsigned i = 0; i < 4; i++) { if (!(vec->dest.write_mask & (1 << i))) continue; if (!(finished_write_mask & (1 << i))) - finished_write_mask |= insert_mov(vec, i, src_idx, shader); - - src_idx++; + finished_write_mask |= insert_mov(vec, i, shader); } nir_instr_remove(&vec->instr); -- 2.30.2