nir/lower-io: add support for lowering inputs
Signed-off-by: Rob Clark <robclark@freedesktop.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 5410f0b..c96eaf9 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2279,7 +2279,8 @@
bool nir_lower_locals_to_regs(nir_shader *shader);
-void nir_lower_io_to_temporaries(nir_shader *shader, nir_function *entrypoint);
+void nir_lower_io_to_temporaries(nir_shader *shader, nir_function *entrypoint,
+ bool outputs, bool inputs);
void nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint);
diff --git a/src/compiler/nir/nir_lower_io_to_temporaries.c b/src/compiler/nir/nir_lower_io_to_temporaries.c
index 4b4363b..3153a49 100644
--- a/src/compiler/nir/nir_lower_io_to_temporaries.c
+++ b/src/compiler/nir/nir_lower_io_to_temporaries.c
@@ -22,9 +22,12 @@
*/
/*
- * Implements a pass that lowers output variables to a temporary plus an
- * output variable with a single copy at each exit point of the shader.
- * This way the output variable is only ever written.
+ * Implements a pass that lowers output and/or input variables to a
+ * temporary plus an output variable with a single copy at each exit
+ * point of the shader and/or an input variable with a single copy
+ * at the entrance point of the shader. This way the output variable
+ * is only ever written once and/or input is only read once, and there
+ * are no indirect outut/input accesses.
*/
#include "nir.h"
@@ -33,6 +36,7 @@
nir_shader *shader;
nir_function *entrypoint;
struct exec_list old_outputs;
+ struct exec_list old_inputs;
};
static void
@@ -88,6 +92,16 @@
}
}
+static void
+emit_input_copies_impl(struct lower_io_state *state, nir_function_impl *impl)
+{
+ if (impl->function == state->entrypoint) {
+ nir_cursor cursor = nir_before_block(nir_start_block(impl));
+ emit_copies(cursor, state->shader, &state->old_inputs,
+ &state->shader->inputs);
+ }
+}
+
static nir_variable *
create_shadow_temp(struct lower_io_state *state, nir_variable *var)
{
@@ -103,8 +117,8 @@
/* Reparent the constant initializer (if any) */
ralloc_steal(nvar, nvar->constant_initializer);
- /* Give the output a new name with @out-temp appended */
- const char *mode = "out";
+ /* Give the original a new name with @<mode>-temp appended */
+ 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->constant_initializer = NULL;
@@ -113,7 +127,8 @@
}
void
-nir_lower_io_to_temporaries(nir_shader *shader, nir_function *entrypoint)
+nir_lower_io_to_temporaries(nir_shader *shader, nir_function *entrypoint,
+ bool outputs, bool inputs)
{
struct lower_io_state state;
@@ -122,7 +137,16 @@
state.shader = shader;
state.entrypoint = entrypoint;
- exec_list_move_nodes_to(&shader->outputs, &state.old_outputs);
+
+ if (inputs)
+ exec_list_move_nodes_to(&shader->inputs, &state.old_inputs);
+ else
+ exec_list_make_empty(&state.old_inputs);
+
+ if (outputs)
+ exec_list_move_nodes_to(&shader->outputs, &state.old_outputs);
+ else
+ exec_list_make_empty(&state.old_outputs);
/* Walk over all of the outputs turn each output into a temporary and
* make a new variable for the actual output.
@@ -132,15 +156,26 @@
exec_list_push_tail(&shader->outputs, &output->node);
}
+ /* and same for inputs: */
+ nir_foreach_variable(var, &state.old_inputs) {
+ nir_variable *input = create_shadow_temp(&state, var);
+ exec_list_push_tail(&shader->inputs, &input->node);
+ }
+
nir_foreach_function(function, shader) {
if (function->impl == NULL)
continue;
- emit_output_copies_impl(&state, function->impl);
+ if (inputs)
+ emit_input_copies_impl(&state, function->impl);
+
+ if (outputs)
+ emit_output_copies_impl(&state, function->impl);
nir_metadata_preserve(function->impl, nir_metadata_block_index |
nir_metadata_dominance);
}
+ exec_list_append(&shader->globals, &state.old_inputs);
exec_list_append(&shader->globals, &state.old_outputs);
}
diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
index 07d24b2..c501bc1 100644
--- a/src/mesa/drivers/dri/i965/brw_nir.c
+++ b/src/mesa/drivers/dri/i965/brw_nir.c
@@ -563,7 +563,9 @@
/* First, lower the GLSL IR or Mesa IR to NIR */
if (shader_prog) {
nir = glsl_to_nir(shader_prog, stage, options);
- OPT_V(nir_lower_io_to_temporaries, nir_shader_get_entrypoint(nir));
+ OPT_V(nir_lower_io_to_temporaries,
+ nir_shader_get_entrypoint(nir),
+ true, false);
} else {
nir = prog_to_nir(prog, options);
OPT_V(nir_convert_to_ssa); /* turn registers into SSA */