nir/lower_subgroups: Rename lower_shuffle to lower_relative_shuffle

This option only applies to relative shuffles (up/down/xor), and in a
moment we're going to add an option to lower normal shuffles, so rename
it.

While we're here, rename lower_shuffle() to lower_to_shuffle() for
similar reasons.

Reviewed-by: Danylo Piliaiev <dpiliaiev@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14412>

src/amd/vulkan/radv_shader.c

@@ -730,7 +730,7 @@ radv_shader_compile_to_nir(struct radv_device *device, struct vk_shader_module *
                                .ballot_components = 1,
                                .lower_to_scalar = 1,
                                .lower_subgroup_masks = 1,
-                               .lower_shuffle = 1,
+                               .lower_relative_shuffle = 1,
                                .lower_shuffle_to_32bit = 1,
                                .lower_vote_eq = 1,
                                .lower_quad_broadcast_dynamic = 1,

src/compiler/nir/nir.h

@@ -4679,7 +4679,7 @@ typedef struct nir_lower_subgroups_options {
    bool lower_vote_trivial:1;
    bool lower_vote_eq:1;
    bool lower_subgroup_masks:1;
-   bool lower_shuffle:1;
+   bool lower_relative_shuffle:1;
    bool lower_shuffle_to_32bit:1;
    bool lower_shuffle_to_swizzle_amd:1;
    bool lower_quad:1;

src/compiler/nir/nir_lower_subgroups.c

@@ -225,9 +225,11 @@ lower_shuffle_to_swizzle(nir_builder *b, nir_intrinsic_instr *intrin,
    }
 }
 
+/* Lowers "specialized" shuffles to a generic nir_intrinsic_shuffle. */
+
 static nir_ssa_def *
-lower_shuffle(nir_builder *b, nir_intrinsic_instr *intrin,
+lower_to_shuffle(nir_builder *b, nir_intrinsic_instr *intrin,
-              const nir_lower_subgroups_options *options)
+                 const nir_lower_subgroups_options *options)
 {
    if (intrin->intrinsic == nir_intrinsic_shuffle_xor &&
        options->lower_shuffle_to_swizzle_amd &&
@@ -479,7 +481,7 @@ lower_dynamic_quad_broadcast(nir_builder *b, nir_intrinsic_instr *intrin,
                              const nir_lower_subgroups_options *options)
 {
    if (!options->lower_quad_broadcast_dynamic_to_const)
-      return lower_shuffle(b, intrin, options);
+      return lower_to_shuffle(b, intrin, options);
 
    nir_ssa_def *dst = NULL;
 
@@ -708,8 +710,8 @@ lower_subgroups_instr(nir_builder *b, nir_instr *instr, void *_options)
    case nir_intrinsic_shuffle_xor:
    case nir_intrinsic_shuffle_up:
    case nir_intrinsic_shuffle_down:
-      if (options->lower_shuffle)
+      if (options->lower_relative_shuffle)
-         return lower_shuffle(b, intrin, options);
+         return lower_to_shuffle(b, intrin, options);
       else if (options->lower_to_scalar && intrin->num_components > 1)
          return lower_subgroup_op_to_scalar(b, intrin, options->lower_shuffle_to_32bit);
       else if (options->lower_shuffle_to_32bit && intrin->src[0].ssa->bit_size == 64)

src/intel/compiler/brw_nir.c

@@ -861,7 +861,7 @@ brw_preprocess_nir(const struct brw_compiler *compiler, nir_shader *nir,
       .ballot_components = 1,
       .lower_to_scalar = true,
       .lower_vote_trivial = !is_scalar,
-      .lower_shuffle = true,
+      .lower_relative_shuffle = true,
       .lower_quad_broadcast_dynamic = true,
       .lower_elect = true,
    };