nir: add load_mesh_view_count and load_mesh_view_indices intrinsics

Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Acked-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14263>

src/compiler/nir/nir.c

@@ -2461,6 +2461,8 @@ nir_intrinsic_from_system_value(gl_system_value val)
       return nir_intrinsic_load_ray_geometry_index;
    case SYSTEM_VALUE_RAY_INSTANCE_CUSTOM_INDEX:
       return nir_intrinsic_load_ray_instance_custom_index;
+   case SYSTEM_VALUE_MESH_VIEW_COUNT:
+      return nir_intrinsic_load_mesh_view_count;
    case SYSTEM_VALUE_FRAG_SHADING_RATE:
       return nir_intrinsic_load_frag_shading_rate;
    default:
@@ -2602,6 +2604,8 @@ nir_system_value_from_intrinsic(nir_intrinsic_op intrin)
       return SYSTEM_VALUE_RAY_INSTANCE_CUSTOM_INDEX;
    case nir_intrinsic_load_frag_shading_rate:
       return SYSTEM_VALUE_FRAG_SHADING_RATE;
+   case nir_intrinsic_load_mesh_view_count:
+      return SYSTEM_VALUE_MESH_VIEW_COUNT;
    default:
       unreachable("intrinsic doesn't produce a system value");
    }

src/compiler/nir/nir_intrinsics.py

@@ -1020,6 +1020,10 @@ intrinsic("printf", src_comp=[1, 1], dest_comp=1, bit_sizes=[32])
 # the driver to at least provide a base location
 system_value("printf_buffer_address", 1, bit_sizes=[32,64])
 
+# Mesh shading MultiView intrinsics
+system_value("mesh_view_count", 1)
+load("mesh_view_indices", [1], [BASE, RANGE], [CAN_ELIMINATE, CAN_REORDER])
+
 # IR3-specific version of most SSBO intrinsics. The only different
 # compare to the originals is that they add an extra source to hold
 # the dword-offset, which is needed by the backend code apart from

src/compiler/nir/nir_lower_system_values.c

@@ -137,7 +137,8 @@ lower_system_value_instr(nir_builder *b, nir_instr *instr, void *_state)
          assert(deref->deref_type == nir_deref_type_var);
          assert(deref->var->data.location == SYSTEM_VALUE_SAMPLE_MASK_IN ||
                 deref->var->data.location == SYSTEM_VALUE_RAY_OBJECT_TO_WORLD ||
-                deref->var->data.location == SYSTEM_VALUE_RAY_WORLD_TO_OBJECT);
+                deref->var->data.location == SYSTEM_VALUE_RAY_WORLD_TO_OBJECT ||
+                deref->var->data.location == SYSTEM_VALUE_MESH_VIEW_INDICES);
       }
       nir_variable *var = deref->var;
 
@@ -207,6 +208,11 @@ lower_system_value_instr(nir_builder *b, nir_instr *instr, void *_state)
          break;
       }
 
+      case SYSTEM_VALUE_MESH_VIEW_INDICES:
+         return nir_load_mesh_view_indices(b, intrin->dest.ssa.num_components,
+               bit_size, column, .base = 0,
+               .range = intrin->dest.ssa.num_components * bit_size / 8);
+
       default:
          break;
       }