I had some very minor comments but, with those addressed 1-4 are Reviewed-by: Jason Ekstrand <<a href="mailto:jason.ekstrand@intel.com">jason.ekstrand@intel.com</a>> <div class="gmail_quote">On Dec 11, 2015 1:24 PM, "Kenneth Graunke" <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Instead of performing the read-modify-write cycle in glsl->nir, we can simply emit a partial writemask. For locals, nir_lower_vars_to_ssa will do the equivalent read-modify-write cycle for us, so we continue to get the same SSA values we had before. Because glsl_to_nir calls nir_lower_outputs_to_temporaries, all outputs are shadowed with temporary values, and written out as whole vectors at the end of the shader. So, most consumers will still not see partial writemasks. However, nir_lower_outputs_to_temporaries bails for tessellation control shader outputs. So those remain actual variables, and stores to those variables now get a writemask. nir_lower_io passes that through. This means that TCS outputs should actually work now. This is a functional change for tessellation control shaders. v2: Relax the nir_validate assert to allow partial writemasks. Signed-off-by: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> --- src/glsl/nir/glsl_to_nir.cpp | 39 +++++++++------------------------------ src/glsl/nir/nir_validate.c | 3 +-- 2 files changed, 10 insertions(+), 32 deletions(-) diff --git a/src/glsl/nir/glsl_to_nir.cpp b/src/glsl/nir/glsl_to_nir.cpp index 14f3153..a45e2a0 100644 --- a/src/glsl/nir/glsl_to_nir.cpp +++ b/src/glsl/nir/glsl_to_nir.cpp @@ -1130,44 +1130,23 @@ nir_visitor::visit(ir_assignment *ir) nir_ssa_def *src = evaluate_rvalue(ir->rhs); if (ir->write_mask != (1 << num_components) - 1 && ir->write_mask != 0) { - /* - * We have no good way to update only part of a variable, so just load - * the LHS and do a vec operation to combine the old with the new, and - * then store it - * back into the LHS. Copy propagation should get rid of the mess. + /* GLSL IR will give us the input to the write-masked assignment in a + * single packed vector. So, for example, if the writemask is xzw, then + * we have to swizzle x -> x, y -> z, and z -> w and get the y component + * from the load. */ - - nir_intrinsic_instr *load = - nir_intrinsic_instr_create(this->shader, nir_intrinsic_load_var); - load->num_components = ir->lhs->type->vector_elements; - nir_ssa_dest_init(&load->instr, &load->dest, num_components, NULL); - load->variables[0] = lhs_deref; - ralloc_steal(load, load->variables[0]); - nir_builder_instr_insert(&b, &load->instr); - - nir_ssa_def *srcs[4]; - + unsigned swiz[4]; unsigned component = 0; - for (unsigned i = 0; i < ir->lhs->type->vector_elements; i++) { - if (ir->write_mask & (1 << i)) { - /* GLSL IR will give us the input to the write-masked assignment - * in a single packed vector. So, for example, if the - * writemask is xzw, then we have to swizzle x -> x, y -> z, - * and z -> w and get the y component from the load. - */ - srcs[i] = nir_channel(&b, src, component++); - } else { - srcs[i] = nir_channel(&b, &load->dest.ssa, i); - } + for (unsigned i = 0; i < 4; i++) { + swiz[i] = ir->write_mask & (1 << i) ? component++ : 0; } - - src = nir_vec(&b, srcs, ir->lhs->type->vector_elements); + src = nir_swizzle(&b, src, swiz, num_components, !supports_ints); } nir_intrinsic_instr *store = nir_intrinsic_instr_create(this->shader, nir_intrinsic_store_var); store->num_components = ir->lhs->type->vector_elements; - store->const_index[0] = (1 << store->num_components) - 1; + store->const_index[0] = ir->write_mask; nir_deref *store_deref = nir_copy_deref(store, &lhs_deref->deref); store->variables[0] = nir_deref_as_var(store_deref); store->src[0] = nir_src_for_ssa(src); diff --git a/src/glsl/nir/nir_validate.c b/src/glsl/nir/nir_validate.c index 89cf0b8..da92055 100644 --- a/src/glsl/nir/nir_validate.c +++ b/src/glsl/nir/nir_validate.c @@ -417,8 +417,7 @@ validate_intrinsic_instr(nir_intrinsic_instr *instr, validate_state *state) assert(instr->variables[0]->var->data.mode != nir_var_shader_in && instr->variables[0]->var->data.mode != nir_var_uniform && instr->variables[0]->var->data.mode != nir_var_shader_storage); - /* Currently, writemasks must cover the entire value */ - assert(instr->const_index[0] == (1 << instr->num_components) - 1); + assert((instr->const_index[0] & ~((1 << instr->num_components) - 1)) == 0); break; } case nir_intrinsic_copy_var: -- 2.6.3 _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">http://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div>