[Mesa-dev] [PATCH v2 1/2] nir/lower_io: Return has_indirect flag from get_io_offset().

[Kenneth Graunke]

get_io_offset() already walks the dereference chain and discovers
whether or not we have an indirect; we can just return that rather than
computing it a second time.  This means moving the call a bit earlier.

More importantly, I'm about to introduce special handling for the
outermost array index, which would require changing the dereference
we pass to deref_has_indirect().  Or we can just eliminate that.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/glsl/nir/nir_lower_io.c | 41 ++++++++++++++---------------------------
 1 file changed, 14 insertions(+), 27 deletions(-)

This replaces patches 3-5 of my recent 23 patch series:

[PATCH 03/23] nir/lower_io: Switch on shader stage for inputs in load_op().
[PATCH 04/23] nir/lower_io: Make get_io_offset take a nir_deref, not a nir_deref_var.
[PATCH 05/23] nir: Introduce new nir_intrinsic_load_per_vertex_input intrinsics.

diff --git a/src/glsl/nir/nir_lower_io.c b/src/glsl/nir/nir_lower_io.c
index f32c09d..80967fc 100644
--- a/src/glsl/nir/nir_lower_io.c
+++ b/src/glsl/nir/nir_lower_io.c
@@ -63,22 +63,9 @@ nir_assign_var_locations(struct exec_list *var_list, unsigned *size,
    *size = location;
 }
 
-static bool
-deref_has_indirect(nir_deref_var *deref)
-{
-   for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) {
-      if (tail->deref_type == nir_deref_type_array) {
-         nir_deref_array *arr = nir_deref_as_array(tail);
-         if (arr->deref_array_type == nir_deref_array_type_indirect)
-            return true;
-      }
-   }
-
-   return false;
-}
-
 static unsigned
-get_io_offset(nir_deref_var *deref, nir_instr *instr, nir_src *indirect,
+get_io_offset(nir_deref_var *deref, nir_instr *instr,
+              nir_src *indirect, bool *has_indirect,
               struct lower_io_state *state)
 {
    bool found_indirect = false;
@@ -122,6 +109,7 @@ get_io_offset(nir_deref_var *deref, nir_instr *instr, nir_src *indirect,
       }
    }
 
+   *has_indirect = found_indirect;
    return base_offset;
 }
 
@@ -169,17 +157,17 @@ nir_lower_io_block(nir_block *block, void *void_state)
          if (mode != nir_var_shader_in && mode != nir_var_uniform)
             continue;
 
-         bool has_indirect = deref_has_indirect(intrin->variables[0]);
+         nir_src indirect;
+         bool has_indirect;
+
+         unsigned offset = get_io_offset(intrin->variables[0], &intrin->instr,
+                                         &indirect, &has_indirect, state);
 
          nir_intrinsic_instr *load =
             nir_intrinsic_instr_create(state->mem_ctx,
                                        load_op(mode, has_indirect));
          load->num_components = intrin->num_components;
 
-         nir_src indirect;
-         unsigned offset = get_io_offset(intrin->variables[0],
-                                         &intrin->instr, &indirect, state);
-
          unsigned location = intrin->variables[0]->var->data.driver_location;
          if (mode == nir_var_uniform) {
             load->const_index[0] = location;
@@ -209,7 +197,12 @@ nir_lower_io_block(nir_block *block, void *void_state)
          if (intrin->variables[0]->var->data.mode != nir_var_shader_out)
             continue;
 
-         bool has_indirect = deref_has_indirect(intrin->variables[0]);
+         nir_src indirect;
+         bool has_indirect;
+
+         unsigned offset = get_io_offset(intrin->variables[0], &intrin->instr,
+                                         &indirect, &has_indirect, state);
+         offset += intrin->variables[0]->var->data.driver_location;
 
          nir_intrinsic_op store_op;
          if (has_indirect) {
@@ -221,12 +214,6 @@ nir_lower_io_block(nir_block *block, void *void_state)
          nir_intrinsic_instr *store = nir_intrinsic_instr_create(state->mem_ctx,
                                                                  store_op);
          store->num_components = intrin->num_components;
-
-         nir_src indirect;
-         unsigned offset = get_io_offset(intrin->variables[0],
-                                         &intrin->instr, &indirect, state);
-         offset += intrin->variables[0]->var->data.driver_location;
-
          store->const_index[0] = offset;
 
          nir_src_copy(&store->src[0], &intrin->src[0], store);
-- 
2.5.3