From aee3d8f0d940a87dba7eae86c9462a3cb3a7d702 Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Tue, 19 Jul 2016 20:35:26 -0700 Subject: [PATCH] nir: Handle FB fetch outputs correctly in nir_lower_io_to_temporaries. This requires emitting a series of copies at the top of the program from each output variable to the corresponding temporary. The initial copy can be skipped for non-framebuffer fetch outputs whose initial value is undefined, and the final copy needs to be skipped for read-only outputs (i.e. gl_LastFragData), since it would be illegal to emit a store output intrinsic for it. Reviewed-by: Kenneth Graunke --- .../nir/nir_lower_io_to_temporaries.c | 21 +++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/src/compiler/nir/nir_lower_io_to_temporaries.c b/src/compiler/nir/nir_lower_io_to_temporaries.c index 3153a49b7be..c8f94ff6eb5 100644 --- a/src/compiler/nir/nir_lower_io_to_temporaries.c +++ b/src/compiler/nir/nir_lower_io_to_temporaries.c @@ -49,6 +49,21 @@ emit_copies(nir_cursor cursor, nir_shader *shader, struct exec_list *new_vars, nir_variable *newv = exec_node_data(nir_variable, new_node, node); nir_variable *temp = exec_node_data(nir_variable, old_node, node); + /* No need to copy the contents of a non-fb_fetch_output output variable + * to the temporary allocated for it, since its initial value is + * undefined. + */ + if (temp->data.mode == nir_var_shader_out && + !temp->data.fb_fetch_output) + continue; + + /* Can't copy the contents of the temporary back to a read-only + * interface variable. The value of the temporary won't have been + * modified by the shader anyway. + */ + if (newv->data.read_only) + continue; + nir_intrinsic_instr *copy = nir_intrinsic_instr_create(shader, nir_intrinsic_copy_var); copy->variables[0] = nir_deref_var_create(copy, newv); @@ -79,6 +94,10 @@ emit_output_copies_impl(struct lower_io_state *state, nir_function_impl *impl) } } } else if (impl->function == state->entrypoint) { + nir_cursor cursor = nir_before_block(nir_start_block(impl)); + emit_copies(cursor, state->shader, &state->old_outputs, + &state->shader->outputs); + /* For all other shader types, we need to do the copies right before * the jumps to the end block. */ @@ -121,6 +140,8 @@ create_shadow_temp(struct lower_io_state *state, nir_variable *var) const char *mode = (temp->data.mode == nir_var_shader_in) ? "in" : "out"; temp->name = ralloc_asprintf(var, "%s@%s-temp", mode, nvar->name); temp->data.mode = nir_var_global; + temp->data.read_only = false; + temp->data.fb_fetch_output = false; temp->constant_initializer = NULL; return nvar; -- 2.30.2