diff --git a/libs/vkd3d-shader/dxbc.c b/libs/vkd3d-shader/dxbc.c
index 93fc993e..f6ac8e08 100644
--- a/libs/vkd3d-shader/dxbc.c
+++ b/libs/vkd3d-shader/dxbc.c
@@ -419,8 +419,6 @@ static int shader_parse_signature(const struct vkd3d_shader_dxbc_section_desc *s
         const char *name;
         uint32_t mask;
 
-        e[i].sort_index = i;
-
         if (has_stream_index)
             e[i].stream_index = read_u32(&ptr);
         else
diff --git a/libs/vkd3d-shader/ir.c b/libs/vkd3d-shader/ir.c
index 4e9fed07..14cf23e8 100644
--- a/libs/vkd3d-shader/ir.c
+++ b/libs/vkd3d-shader/ir.c
@@ -1471,6 +1471,9 @@ static bool shader_signature_merge(struct shader_signature *s, uint8_t range_map
         return false;
     memcpy(elements, s->elements, element_count * sizeof(*elements));
 
+    for (i = 0; i < element_count; ++i)
+        elements[i].sort_index = i;
+
     qsort(elements, element_count, sizeof(elements[0]), signature_element_register_compare);
 
     for (i = 0, new_count = 0; i < element_count; i = j, elements[new_count++] = *e)
diff --git a/libs/vkd3d-shader/vkd3d_shader_private.h b/libs/vkd3d-shader/vkd3d_shader_private.h
index 9aee685f..aab94f77 100644
--- a/libs/vkd3d-shader/vkd3d_shader_private.h
+++ b/libs/vkd3d-shader/vkd3d_shader_private.h
@@ -1061,6 +1061,9 @@ enum vkd3d_shader_input_sysval_semantic
 
 struct signature_element
 {
+    /* sort_index is not a property of the signature element, it is just a
+     * convenience field used to retain the original order in a signature and
+     * recover it after having permuted the signature itself. */
     unsigned int sort_index;
     const char *semantic_name;
     unsigned int semantic_index;