[Mesa-dev] [PATCH] nir/derefs: Add a nir_derefs_do_not_alias enum value

[Jason Ekstrand]

This makes some of the code more clear.
---
 src/compiler/nir/nir_deref.c | 8 ++++----
 src/compiler/nir/nir_deref.h | 1 +
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/compiler/nir/nir_deref.c b/src/compiler/nir/nir_deref.c
index 59b36a7f255..68a3aad5c70 100644
--- a/src/compiler/nir/nir_deref.c
+++ b/src/compiler/nir/nir_deref.c
@@ -289,7 +289,7 @@ nir_compare_deref_paths(nir_deref_path *a_path,
                         nir_deref_path *b_path)
 {
    if (!modes_may_alias(b_path->path[0]->mode, a_path->path[0]->mode))
-      return 0;
+      return nir_derefs_do_not_alias;
 
    if (a_path->path[0]->deref_type != b_path->path[0]->deref_type)
       return nir_derefs_may_alias_bit;
@@ -299,7 +299,7 @@ nir_compare_deref_paths(nir_deref_path *a_path,
        * they're not the same variable, we know they can't possibly alias.
        */
       if (a_path->path[0]->var != b_path->path[0]->var)
-         return 0;
+         return nir_derefs_do_not_alias;
    } else {
       assert(a_path->path[0]->deref_type == nir_deref_type_cast);
       /* If they're not exactly the same cast, we can't compare them so we
@@ -357,7 +357,7 @@ nir_compare_deref_paths(nir_deref_path *a_path,
                 */
                if (nir_src_as_uint(a_tail->arr.index) !=
                    nir_src_as_uint(b_tail->arr.index))
-                  return 0;
+                  return nir_derefs_do_not_alias;
             } else if (a_tail->arr.index.ssa == b_tail->arr.index.ssa) {
                /* They're the same indirect, continue on */
             } else {
@@ -373,7 +373,7 @@ nir_compare_deref_paths(nir_deref_path *a_path,
       case nir_deref_type_struct: {
          /* If they're different struct members, they don't even alias */
          if (a_tail->strct.index != b_tail->strct.index)
-            return 0;
+            return nir_derefs_do_not_alias;
          break;
       }
 
diff --git a/src/compiler/nir/nir_deref.h b/src/compiler/nir/nir_deref.h
index c61c3f9366f..20d40377e6e 100644
--- a/src/compiler/nir/nir_deref.h
+++ b/src/compiler/nir/nir_deref.h
@@ -55,6 +55,7 @@ nir_ssa_def *nir_build_deref_offset(nir_builder *b, nir_deref_instr *deref,
                                     glsl_type_size_align_func size_align);
 
 typedef enum {
+   nir_derefs_do_not_alias     = 0,
    nir_derefs_equal_bit        = (1 << 0),
    nir_derefs_may_alias_bit    = (1 << 1),
    nir_derefs_a_contains_b_bit = (1 << 2),
-- 
2.19.1