nir/glsl: set deref cast mode during function inlining

See code comment for details.

Issue: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11535
Fixes: c6c150b4cd ("glsl_to_nir: support conversion of opaque function params")

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30338>

src/compiler/glsl/glsl_to_nir.cpp

@@ -2528,13 +2528,8 @@ nir_visitor::visit(ir_dereference_variable *ir)
          i++;
       }
 
-      nir_variable_mode mode =
-         glsl_contains_opaque(ir->variable_referenced()->type) &&
-         ir->variable_referenced()->data.mode == ir_var_function_in ?
-            nir_var_uniform : nir_var_function_temp;
-
       this->deref = nir_build_deref_cast(&b, nir_load_param(&b, i),
-                                         mode, ir->type, 0);
+                                         nir_var_function_temp, ir->type, 0);
       return;
    }
 

src/compiler/nir/nir_functions.c

@@ -53,6 +53,30 @@ function_ends_in_jump(nir_function_impl *impl)
    return nir_block_ends_in_jump(last_block);
 }
 
+/* A cast is used to deref function in/out params. However the bindless
+ * textures spec allows both uniforms and functions temps to be passed to a
+ * function param defined the same way. To deal with this we need to update
+ * this when we inline and know what variable mode we are dealing with.
+ */
+static void
+fixup_cast_deref_mode(nir_deref_instr *deref)
+{
+   nir_deref_instr *parent = nir_src_as_deref(deref->parent);
+   if (parent && parent->modes & nir_var_uniform &&
+       deref->modes & nir_var_function_temp) {
+      deref->modes |= nir_var_uniform;
+      deref->modes ^= nir_var_function_temp;
+
+      nir_foreach_use(use, &deref->def) {
+         if (nir_src_parent_instr(use)->type != nir_instr_type_deref)
+            continue;
+
+         /* Recurse into children */
+         fixup_cast_deref_mode(nir_instr_as_deref(nir_src_parent_instr(use)));
+      }
+   }
+}
+
 void
 nir_inline_function_impl(struct nir_builder *b,
                          const nir_function_impl *impl,
@@ -68,6 +92,17 @@ nir_inline_function_impl(struct nir_builder *b,
          switch (instr->type) {
          case nir_instr_type_deref: {
             nir_deref_instr *deref = nir_instr_as_deref(instr);
+
+            /* Note: This shouldn't change the mode of anything but the
+             * replaced nir_intrinsic_load_param intrinsics handled later in
+             * this switch table. Any incorrect modes should have already been
+             * detected by previous nir_vaidate calls.
+             */
+            if (deref->deref_type == nir_deref_type_cast) {
+               fixup_cast_deref_mode(deref);
+               break;
+            }
+
             if (deref->deref_type != nir_deref_type_var)
                break;