nir: Use var->data.mode instead of deref->mode in a few cases

We already have the variable so we know the mode exactly.  Just use that
instead of the deref mode.  If these paths ever have to handle variable
pointers (not likely since they're OpenGL-specific), we can fix them to
handle crazy deref modes then.

Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6332>

src/compiler/glsl/gl_nir_lower_images.c

@@ -87,7 +87,7 @@ lower_impl(nir_builder *b, nir_instr *instr, bool bindless_only)
       return false;
    }
 
-   bool bindless = deref->mode != nir_var_uniform || var->data.bindless;
+   bool bindless = var->data.mode != nir_var_uniform || var->data.bindless;
    if (bindless_only && !bindless)
       return false;
 

src/compiler/nir/nir_lower_io.c

@@ -634,8 +634,8 @@ nir_lower_io_block(nir_block *block,
       nir_ssa_def *offset;
       nir_ssa_def *vertex_index = NULL;
       unsigned component_offset = var->data.location_frac;
-      bool bindless_type_size = mode == nir_var_shader_in ||
-                                mode == nir_var_shader_out ||
+      bool bindless_type_size = var->data.mode == nir_var_shader_in ||
+                                var->data.mode == nir_var_shader_out ||
                                 var->data.bindless;
 
      if (nir_deref_instr_is_known_out_of_bounds(deref)) {

src/compiler/nir/nir_lower_io_to_scalar.c

@@ -314,11 +314,11 @@ nir_lower_io_to_scalar_early_instr(nir_builder *b, nir_instr *instr, void *data)
       return false;
 
    nir_deref_instr *deref = nir_src_as_deref(intr->src[0]);
-   nir_variable_mode mode = deref->mode;
-   if (!(mode & state->mask))
+   if (!(deref->mode & state->mask))
       return false;
 
    nir_variable *var = nir_deref_instr_get_variable(deref);
+   nir_variable_mode mode = var->data.mode;
 
    /* TODO: add patch support */
    if (var->data.patch)

src/compiler/nir/nir_lower_io_to_vector.c

@@ -442,10 +442,10 @@ nir_lower_io_to_vector_impl(nir_function_impl *impl, nir_variable_mode modes)
 
             const unsigned loc = get_slot(old_var);
             const unsigned old_frac = old_var->data.location_frac;
-            nir_variable *new_var = old_deref->mode == nir_var_shader_in ?
+            nir_variable *new_var = old_var->data.mode == nir_var_shader_in ?
                                     new_inputs[loc][old_frac] :
                                     new_outputs[loc][old_frac];
-            bool flat = old_deref->mode == nir_var_shader_in ?
+            bool flat = old_var->data.mode == nir_var_shader_in ?
                         flat_inputs[loc] : flat_outputs[loc];
             if (!new_var)
                break;

src/compiler/nir/nir_opt_large_constants.c

@@ -208,7 +208,7 @@ nir_opt_large_constants(nir_shader *shader,
              */
             nir_deref_instr *deref = nir_instr_as_deref(instr);
             if (deref->deref_type == nir_deref_type_var &&
-                deref->mode == nir_var_function_temp &&
+                deref->var->data.mode == nir_var_function_temp &&
                 nir_deref_instr_has_complex_use(deref))
                var_infos[deref->var->index].is_constant = false;
             continue;

src/compiler/nir/nir_remove_dead_variables.c

@@ -70,8 +70,9 @@ add_var_use_deref(nir_deref_instr *deref, struct set *live)
    /* If it's not a local that never escapes the shader, then any access at
     * all means we need to keep it alive.
     */
-   assert(deref->mode == deref->var->data.mode);
-   if (!(deref->mode & (nir_var_function_temp | nir_var_shader_temp | nir_var_mem_shared)) ||
+   if (!(deref->var->data.mode & (nir_var_function_temp |
+                                  nir_var_shader_temp |
+                                  nir_var_mem_shared)) ||
        deref_used_for_not_store(deref))
       _mesa_set_add(live, deref->var);
 }

src/gallium/drivers/radeonsi/si_shader_nir.c

@@ -189,7 +189,7 @@ static void scan_instruction(const struct nir_shader *nir, struct si_shader_info
       nir_variable *var = deref ? nir_deref_instr_get_variable(deref) : NULL;
 
       if (var) {
-         if (deref->mode != nir_var_uniform || var->data.bindless)
+         if (var->data.mode != nir_var_uniform || var->data.bindless)
             info->uses_bindless_samplers = true;
       }
    } else if (instr->type == nir_instr_type_intrinsic) {