nir: Add intrinsics for object to/from world RT sysvals

These are a bit more tricky than most because they're matrix system
values.  We make the intentional choice here to not bother with allowing
indirect addressing of columns for these.  Since they're system values,
they may be magically constructed somehow or come from weird hardware so
it's easier on back-ends to just handle any indirects with bcsel.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6479>

src/compiler/nir/nir.c

@@ -2232,6 +2232,10 @@ nir_intrinsic_from_system_value(gl_system_value val)
       return nir_intrinsic_load_ray_t_min;
    case SYSTEM_VALUE_RAY_T_MAX:
       return nir_intrinsic_load_ray_t_max;
+   case SYSTEM_VALUE_RAY_OBJECT_TO_WORLD:
+      return nir_intrinsic_load_ray_object_to_world;
+   case SYSTEM_VALUE_RAY_WORLD_TO_OBJECT:
+      return nir_intrinsic_load_ray_world_to_object;
    case SYSTEM_VALUE_RAY_HIT_KIND:
       return nir_intrinsic_load_ray_hit_kind;
    case SYSTEM_VALUE_RAY_FLAGS:
@@ -2363,6 +2367,10 @@ nir_system_value_from_intrinsic(nir_intrinsic_op intrin)
       return SYSTEM_VALUE_RAY_T_MIN;
    case nir_intrinsic_load_ray_t_max:
       return SYSTEM_VALUE_RAY_T_MAX;
+   case nir_intrinsic_load_ray_object_to_world:
+      return SYSTEM_VALUE_RAY_OBJECT_TO_WORLD;
+   case nir_intrinsic_load_ray_world_to_object:
+      return SYSTEM_VALUE_RAY_WORLD_TO_OBJECT;
    case nir_intrinsic_load_ray_hit_kind:
       return SYSTEM_VALUE_RAY_HIT_KIND;
    case nir_intrinsic_load_ray_flags:

src/compiler/nir/nir.h

@@ -1791,6 +1791,11 @@ typedef enum {
     */
    NIR_INTRINSIC_COMPONENT,
 
+   /**
+    * Column index for matrix intrinsics.
+    */
+   NIR_INTRINSIC_COLUMN,
+
    /**
     * Interpolation mode (only meaningful for FS inputs).
     */
@@ -2057,6 +2062,7 @@ INTRINSIC_IDX_ACCESSORS(range_base, RANGE_BASE, unsigned)
 INTRINSIC_IDX_ACCESSORS(desc_set, DESC_SET, unsigned)
 INTRINSIC_IDX_ACCESSORS(binding, BINDING, unsigned)
 INTRINSIC_IDX_ACCESSORS(component, COMPONENT, unsigned)
+INTRINSIC_IDX_ACCESSORS(column, COLUMN, unsigned)
 INTRINSIC_IDX_ACCESSORS(interp_mode, INTERP_MODE, unsigned)
 INTRINSIC_IDX_ACCESSORS(reduction_op, REDUCTION_OP, unsigned)
 INTRINSIC_IDX_ACCESSORS(cluster_size, CLUSTER_SIZE, unsigned)

src/compiler/nir/nir_intrinsics.py

@@ -101,6 +101,8 @@ DESC_SET = "NIR_INTRINSIC_DESC_SET"
 BINDING = "NIR_INTRINSIC_BINDING"
 # Component offset
 COMPONENT = "NIR_INTRINSIC_COMPONENT"
+# Column index for matrix system values
+COLUMN = "NIR_INTRINSIC_COLUMN"
 # Interpolation mode (only meaningful for FS inputs)
 INTERP_MODE = "NIR_INTRINSIC_INTERP_MODE"
 # A binary nir_op to use when performing a reduction or scan operation
@@ -667,6 +669,8 @@ system_value("ray_object_origin", 3)
 system_value("ray_object_direction", 3)
 system_value("ray_t_min", 1)
 system_value("ray_t_max", 1)
+system_value("ray_object_to_world", 3, indices=[COLUMN])
+system_value("ray_world_to_object", 3, indices=[COLUMN])
 system_value("ray_hit_kind", 1)
 system_value("ray_flags", 1)
 system_value("ray_geometry_index", 1)

src/compiler/nir/nir_lower_system_values.c

@@ -113,14 +113,20 @@ lower_system_value_instr(nir_builder *b, nir_instr *instr, void *_state)
       if (!nir_deref_mode_is(deref, nir_var_system_value))
          return NULL;
 
+      nir_ssa_def *column = NULL;
       if (deref->deref_type != nir_deref_type_var) {
-         /* The only one system value that is an array and that is
+         /* The only one system values that aren't plane variables are
-          * gl_SampleMask which is always an array of one element.
+          * gl_SampleMask which is always an array of one element and a
+          * couple of ray-tracing intrinsics which are matrices.
           */
          assert(deref->deref_type == nir_deref_type_array);
+         assert(deref->arr.index.is_ssa);
+         column = deref->arr.index.ssa;
          deref = nir_deref_instr_parent(deref);
          assert(deref->deref_type == nir_deref_type_var);
-         assert(deref->var->data.location == SYSTEM_VALUE_SAMPLE_MASK_IN);
+         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);
       }
       nir_variable *var = deref->var;
 
@@ -186,10 +192,26 @@ lower_system_value_instr(nir_builder *b, nir_instr *instr, void *_state)
 
       nir_intrinsic_op sysval_op =
          nir_intrinsic_from_system_value(var->data.location);
+      if (glsl_type_is_matrix(var->type)) {
+         assert(nir_intrinsic_infos[sysval_op].index_map[NIR_INTRINSIC_COLUMN] > 0);
+         unsigned num_cols = glsl_get_matrix_columns(var->type);
+         ASSERTED unsigned num_rows = glsl_get_vector_elements(var->type);
+         assert(num_rows == intrin->dest.ssa.num_components);
+
+         nir_ssa_def *cols[4];
+         for (unsigned i = 0; i < num_cols; i++) {
+            cols[i] = nir_load_system_value(b, sysval_op, i,
+                                            intrin->dest.ssa.num_components,
+                                            intrin->dest.ssa.bit_size);
+            assert(cols[i]->num_components == num_rows);
+         }
+         return nir_select_from_ssa_def_array(b, cols, num_cols, column);
+      } else {
          return nir_load_system_value(b, sysval_op, 0,
                                       intrin->dest.ssa.num_components,
                                       intrin->dest.ssa.bit_size);
       }
+   }
 
    default:
       return NULL;

src/compiler/nir/nir_print.c

@@ -830,6 +830,7 @@ print_intrinsic_instr(nir_intrinsic_instr *instr, print_state *state)
       [NIR_INTRINSIC_DESC_SET] = "desc-set",
       [NIR_INTRINSIC_BINDING] = "binding",
       [NIR_INTRINSIC_COMPONENT] = "component",
+      [NIR_INTRINSIC_COLUMN] = "column",
       [NIR_INTRINSIC_INTERP_MODE] = "interp_mode",
       [NIR_INTRINSIC_REDUCTION_OP] = "reduction_op",
       [NIR_INTRINSIC_CLUSTER_SIZE] = "cluster_size",