[Mesa-dev] [PATCH v3 093/104] nir: Remove deref chain support from lower_var_copies

[Jason Ekstrand]

---
 src/compiler/nir/nir_lower_var_copies.c | 138 ++------------------------------
 1 file changed, 6 insertions(+), 132 deletions(-)

diff --git a/src/compiler/nir/nir_lower_var_copies.c b/src/compiler/nir/nir_lower_var_copies.c
index 62bbe50..9326d99 100644
--- a/src/compiler/nir/nir_lower_var_copies.c
+++ b/src/compiler/nir/nir_lower_var_copies.c
@@ -34,128 +34,6 @@
  * Lowers all copy intrinsics to sequences of load/store intrinsics.
  */
 
-/* Walks down the deref chain and returns the next deref in the chain whose
- * child is a wildcard.  In other words, given the chain  a[1].foo[*].bar,
- * this function will return the deref to foo.  Calling it a second time
- * with the [*].bar, it will return NULL.
- */
-static nir_deref *
-deref_next_wildcard_parent(nir_deref *deref)
-{
-   for (nir_deref *tail = deref; tail->child; tail = tail->child) {
-      if (tail->child->deref_type != nir_deref_type_array)
-         continue;
-
-      nir_deref_array *arr = nir_deref_as_array(tail->child);
-
-      if (arr->deref_array_type == nir_deref_array_type_wildcard)
-         return tail;
-   }
-
-   return NULL;
-}
-
-/* This function recursively walks the given deref chain and replaces the
- * given copy instruction with an equivalent sequence load/store
- * operations.
- *
- * @copy_instr    The copy instruction to replace; new instructions will be
- *                inserted before this one
- *
- * @dest_head     The head of the destination variable deref chain
- *
- * @src_head      The head of the source variable deref chain
- *
- * @dest_tail     The current tail of the destination variable deref chain;
- *                this is used for recursion and external callers of this
- *                function should call it with tail == head
- *
- * @src_tail      The current tail of the source variable deref chain;
- *                this is used for recursion and external callers of this
- *                function should call it with tail == head
- *
- * @state         The current variable lowering state
- */
-static void
-emit_copy_load_store(nir_intrinsic_instr *copy_instr,
-                     nir_deref_var *dest_head, nir_deref_var *src_head,
-                     nir_deref *dest_tail, nir_deref *src_tail,
-                     nir_shader *shader)
-{
-   /* Find the next pair of wildcards */
-   nir_deref *src_arr_parent = deref_next_wildcard_parent(src_tail);
-   nir_deref *dest_arr_parent = deref_next_wildcard_parent(dest_tail);
-
-   if (src_arr_parent || dest_arr_parent) {
-      /* Wildcards had better come in matched pairs */
-      assert(src_arr_parent && dest_arr_parent);
-
-      nir_deref_array *src_arr = nir_deref_as_array(src_arr_parent->child);
-      nir_deref_array *dest_arr = nir_deref_as_array(dest_arr_parent->child);
-
-      unsigned length = glsl_get_length(src_arr_parent->type);
-      /* The wildcards should represent the same number of elements */
-      assert(length == glsl_get_length(dest_arr_parent->type));
-      assert(length > 0);
-
-      /* Walk over all of the elements that this wildcard refers to and
-       * call emit_copy_load_store on each one of them */
-      src_arr->deref_array_type = nir_deref_array_type_direct;
-      dest_arr->deref_array_type = nir_deref_array_type_direct;
-      for (unsigned i = 0; i < length; i++) {
-         src_arr->base_offset = i;
-         dest_arr->base_offset = i;
-         emit_copy_load_store(copy_instr, dest_head, src_head,
-                              &dest_arr->deref, &src_arr->deref, shader);
-      }
-      src_arr->deref_array_type = nir_deref_array_type_wildcard;
-      dest_arr->deref_array_type = nir_deref_array_type_wildcard;
-   } else {
-      /* In this case, we have no wildcards anymore, so all we have to do
-       * is just emit the load and store operations. */
-      src_tail = nir_deref_tail(src_tail);
-      dest_tail = nir_deref_tail(dest_tail);
-
-      assert(src_tail->type == dest_tail->type);
-
-      unsigned num_components = glsl_get_vector_elements(src_tail->type);
-      unsigned bit_size = glsl_get_bit_size(src_tail->type);
-
-      nir_intrinsic_instr *load =
-         nir_intrinsic_instr_create(shader, nir_intrinsic_load_var);
-      load->num_components = num_components;
-      load->variables[0] = nir_deref_var_clone(src_head, load);
-      nir_ssa_dest_init(&load->instr, &load->dest, num_components, bit_size,
-                        NULL);
-
-      nir_instr_insert_before(&copy_instr->instr, &load->instr);
-
-      nir_intrinsic_instr *store =
-         nir_intrinsic_instr_create(shader, nir_intrinsic_store_var);
-      store->num_components = num_components;
-      nir_intrinsic_set_write_mask(store, (1 << num_components) - 1);
-      store->variables[0] = nir_deref_var_clone(dest_head, store);
-
-      store->src[0].is_ssa = true;
-      store->src[0].ssa = &load->dest.ssa;
-
-      nir_instr_insert_before(&copy_instr->instr, &store->instr);
-   }
-}
-
-/* Lowers a copy instruction to a sequence of load/store instructions
- *
- * The new instructions are placed before the copy instruction in the IR.
- */
-void
-nir_lower_var_copy_instr(nir_intrinsic_instr *copy, nir_shader *shader)
-{
-   assert(copy->intrinsic == nir_intrinsic_copy_var);
-   emit_copy_load_store(copy, copy->variables[0], copy->variables[1],
-                        &copy->variables[0]->deref,
-                        &copy->variables[1]->deref, shader);
-}
-
 static nir_deref_instr *
 build_deref_to_next_wildcard(nir_builder *b,
                              nir_deref_instr *parent,
@@ -236,7 +114,6 @@ nir_lower_deref_copy_instr(nir_builder *b, nir_intrinsic_instr *copy)
 static bool
 lower_var_copies_impl(nir_function_impl *impl)
 {
-   nir_shader *shader = impl->function->shader;
    bool progress = false;
 
    nir_builder b;
@@ -248,18 +125,15 @@ lower_var_copies_impl(nir_function_impl *impl)
             continue;
 
          nir_intrinsic_instr *copy = nir_instr_as_intrinsic(instr);
-         if (copy->intrinsic == nir_intrinsic_copy_var)
-            nir_lower_var_copy_instr(copy, shader);
-         else if (copy->intrinsic == nir_intrinsic_copy_deref)
-            nir_lower_deref_copy_instr(&b, copy);
-         else
+         if (copy->intrinsic != nir_intrinsic_copy_deref)
             continue;
 
+         nir_lower_deref_copy_instr(&b, copy);
+
          nir_instr_remove(&copy->instr);
-         if (copy->intrinsic == nir_intrinsic_copy_deref) {
-            nir_deref_instr_cleanup(nir_src_as_deref(copy->src[0]));
-            nir_deref_instr_cleanup(nir_src_as_deref(copy->src[1]));
-         }
+         nir_deref_instr_cleanup(nir_src_as_deref(copy->src[0]));
+         nir_deref_instr_cleanup(nir_src_as_deref(copy->src[1]));
+
          progress = true;
          ralloc_free(copy);
       }
-- 
2.5.0.400.gff86faf