brw: check if the FS needs vertex_attributes_bypass to be set

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34445>

src/intel/compiler/brw_compile_fs.cpp

@@ -995,6 +995,8 @@ brw_nir_populate_wm_prog_data(nir_shader *shader,
       const unsigned offset_bary_modes =
          brw_compute_offset_barycentric_interp_modes(key, shader);
 
+      prog_data->vertex_attributes_bypass = brw_needs_vertex_attributes_bypass(shader);
+
       prog_data->uses_npc_bary_coefficients =
          offset_bary_modes & INTEL_BARYCENTRIC_NONPERSPECTIVE_BITS;
       prog_data->uses_pc_bary_coefficients =

src/intel/compiler/brw_compiler.h

@@ -722,6 +722,13 @@ struct brw_wm_prog_data {
    bool contains_flat_varying;
    bool contains_noperspective_varying;
 
+   /** Fragment shader barycentrics
+    *
+    * Request that the HW delta computation of attributes be turned off. This is needed
+    * when the FS has per-vertex inputs or reads BaryCoordKHR/BaryCoordNoPerspKHR.
+    */
+   bool vertex_attributes_bypass;
+
    /** True if the shader wants sample shading
     *
     * This corresponds to whether or not a gl_SampleId, gl_SamplePosition, or

src/intel/compiler/brw_nir.c

@@ -675,6 +675,25 @@ lower_indirect_primitive_id(nir_builder *b,
    return true;
 }
 
+bool
+brw_needs_vertex_attributes_bypass(const nir_shader *shader)
+{
+   /* Even if there are no actual per-vertex inputs, if the fragment
+    * shader uses BaryCoord*, we need to set everything accordingly
+    * so the barycentrics don't get reordered.
+    */
+   if (BITSET_TEST(shader->info.system_values_read, SYSTEM_VALUE_BARYCENTRIC_LINEAR_COORD) ||
+       BITSET_TEST(shader->info.system_values_read, SYSTEM_VALUE_BARYCENTRIC_PERSP_COORD))
+      return true;
+
+   nir_foreach_shader_in_variable(var, shader) {
+      if (var->data.per_vertex)
+         return true;
+   }
+
+   return false;
+}
+
 void
 brw_nir_lower_fs_inputs(nir_shader *nir,
                         const struct intel_device_info *devinfo,

src/intel/compiler/brw_nir.h

@@ -181,6 +181,7 @@ bool brw_nir_lower_cs_intrinsics(nir_shader *nir,
                                  const struct intel_device_info *devinfo,
                                  struct brw_cs_prog_data *prog_data);
 bool brw_nir_lower_alpha_to_coverage(nir_shader *shader);
+bool brw_needs_vertex_attributes_bypass(const nir_shader *shader);
 bool brw_nir_lower_fs_msaa(nir_shader *shader,
                            const struct brw_wm_prog_key *key);