nir/algebraic: mark some optimizations with fsat(NaN) as inexact
[mesa.git] / src / compiler / nir / nir_lower_system_values.c
index 4436799fa527893c5b963b59b4c226517ef73b24..b99f655c2e0d75863185f0c7bc4e2c6b4403ddae 100644 (file)
 #include "nir.h"
 #include "nir_builder.h"
 
-static nir_ssa_def*
-build_local_group_size(nir_builder *b, unsigned bit_size)
-{
-   nir_ssa_def *local_size;
-
-   /*
-    * If the local work group size is variable it can't be lowered at this
-    * point, but its intrinsic can still be used.
-    */
-   if (b->shader->info.cs.local_size_variable) {
-      local_size = nir_load_local_group_size(b);
-   } else {
-      /* using a 32 bit constant is safe here as no device/driver needs more
-       * than 32 bits for the local size */
-      nir_const_value local_size_const;
-      memset(&local_size_const, 0, sizeof(local_size_const));
-      local_size_const.u32[0] = b->shader->info.cs.local_size[0];
-      local_size_const.u32[1] = b->shader->info.cs.local_size[1];
-      local_size_const.u32[2] = b->shader->info.cs.local_size[2];
-      local_size = nir_build_imm(b, 3, 32, local_size_const);
-   }
-
-   return nir_u2u(b, local_size, bit_size);
-}
-
 static nir_ssa_def *
-build_local_invocation_id(nir_builder *b, unsigned bit_size)
+sanitize_32bit_sysval(nir_builder *b, nir_intrinsic_instr *intrin)
 {
-   /* If lower_cs_local_id_from_index is true, then we derive the local
-    * index from the local id.
-    */
-   if (b->shader->options->lower_cs_local_id_from_index) {
-      /* We lower gl_LocalInvocationID from gl_LocalInvocationIndex based
-       * on this formula:
-       *
-       *    gl_LocalInvocationID.x =
-       *       gl_LocalInvocationIndex % gl_WorkGroupSize.x;
-       *    gl_LocalInvocationID.y =
-       *       (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
-       *       gl_WorkGroupSize.y;
-       *    gl_LocalInvocationID.z =
-       *       (gl_LocalInvocationIndex /
-       *        (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
-       *       gl_WorkGroupSize.z;
-       *
-       * However, the final % gl_WorkGroupSize.z does nothing unless we
-       * accidentally end up with a gl_LocalInvocationIndex that is too
-       * large so it can safely be omitted.
-       */
-      nir_ssa_def *local_index = nir_load_local_invocation_index(b);
-      nir_ssa_def *local_size = build_local_group_size(b, 32);
+   assert(intrin->dest.is_ssa);
+   const unsigned bit_size = intrin->dest.ssa.bit_size;
+   if (bit_size == 32)
+      return NULL;
 
-      /* Because no hardware supports a local workgroup size greater than
-       * about 1K, this calculation can be done in 32-bit and can save some
-       * 64-bit arithmetic.
-       */
-      nir_ssa_def *id_x, *id_y, *id_z;
-      id_x = nir_umod(b, local_index,
-                         nir_channel(b, local_size, 0));
-      id_y = nir_umod(b, nir_udiv(b, local_index,
-                                     nir_channel(b, local_size, 0)),
-                         nir_channel(b, local_size, 1));
-      id_z = nir_udiv(b, local_index,
-                         nir_imul(b, nir_channel(b, local_size, 0),
-                                     nir_channel(b, local_size, 1)));
-      return nir_u2u(b, nir_vec3(b, id_x, id_y, id_z), bit_size);
-   } else {
-      return nir_u2u(b, nir_load_local_invocation_id(b), bit_size);
-   }
+   intrin->dest.ssa.bit_size = 32;
+   return nir_u2u(b, &intrin->dest.ssa, bit_size);
 }
 
 static nir_ssa_def*
 build_global_group_size(nir_builder *b, unsigned bit_size)
 {
-   nir_ssa_def *group_size = build_local_group_size(b, bit_size);
-   nir_ssa_def *num_work_groups = nir_u2u(b, nir_load_num_work_groups(b), bit_size);
-   return nir_imul(b, group_size, num_work_groups);
+   nir_ssa_def *group_size = nir_load_local_group_size(b);
+   nir_ssa_def *num_work_groups = nir_load_num_work_groups(b, bit_size);
+   return nir_imul(b, nir_u2u(b, group_size, bit_size),
+                      num_work_groups);
 }
 
-static nir_ssa_def*
-build_global_invocation_id(nir_builder *b, unsigned bit_size)
+static bool
+lower_system_value_filter(const nir_instr *instr, const void *_state)
 {
-   /* From the GLSL man page for gl_GlobalInvocationID:
-    *
-    *    "The value of gl_GlobalInvocationID is equal to
-    *    gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID"
-    */
-   nir_ssa_def *group_size = build_local_group_size(b, bit_size);
-   nir_ssa_def *group_id = nir_u2u(b, nir_load_work_group_id(b), bit_size);
-   nir_ssa_def *local_id = build_local_invocation_id(b, bit_size);
-
-   return nir_iadd(b, nir_imul(b, group_id, group_size), local_id);
+   return instr->type == nir_instr_type_intrinsic;
 }
 
-static bool
-convert_block(nir_block *block, nir_builder *b)
+static nir_ssa_def *
+lower_system_value_instr(nir_builder *b, nir_instr *instr, void *_state)
 {
-   bool progress = false;
+   nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+
+   /* All the intrinsics we care about are loads */
+   if (!nir_intrinsic_infos[intrin->intrinsic].has_dest)
+      return NULL;
+
+   assert(intrin->dest.is_ssa);
+   const unsigned bit_size = intrin->dest.ssa.bit_size;
+
+   switch (intrin->intrinsic) {
+   case nir_intrinsic_load_vertex_id:
+      if (b->shader->options->vertex_id_zero_based) {
+         return nir_iadd(b, nir_load_vertex_id_zero_base(b),
+                            nir_load_first_vertex(b));
+      } else {
+         return NULL;
+      }
+
+   case nir_intrinsic_load_base_vertex:
+      /**
+       * From the OpenGL 4.6 (11.1.3.9 Shader Inputs) specification:
+       *
+       * "gl_BaseVertex holds the integer value passed to the baseVertex
+       * parameter to the command that resulted in the current shader
+       * invocation. In the case where the command has no baseVertex
+       * parameter, the value of gl_BaseVertex is zero."
+       */
+      if (b->shader->options->lower_base_vertex) {
+         return nir_iand(b, nir_load_is_indexed_draw(b),
+                            nir_load_first_vertex(b));
+      } else {
+         return NULL;
+      }
 
-   nir_foreach_instr_safe(instr, block) {
-      if (instr->type != nir_instr_type_intrinsic)
-         continue;
+   case nir_intrinsic_load_helper_invocation:
+      if (b->shader->options->lower_helper_invocation) {
+         nir_ssa_def *tmp;
+         tmp = nir_ishl(b, nir_imm_int(b, 1),
+                           nir_load_sample_id_no_per_sample(b));
+         tmp = nir_iand(b, nir_load_sample_mask_in(b), tmp);
+         return nir_inot(b, nir_i2b(b, tmp));
+      } else {
+         return NULL;
+      }
 
-      nir_intrinsic_instr *load_deref = nir_instr_as_intrinsic(instr);
-      if (load_deref->intrinsic != nir_intrinsic_load_deref)
-         continue;
+   case nir_intrinsic_load_local_invocation_id:
+   case nir_intrinsic_load_local_invocation_index:
+   case nir_intrinsic_load_local_group_size:
+      return sanitize_32bit_sysval(b, intrin);
 
-      nir_deref_instr *deref = nir_src_as_deref(load_deref->src[0]);
+   case nir_intrinsic_load_deref: {
+      nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
       if (deref->mode != nir_var_system_value)
-         continue;
+         return NULL;
 
       if (deref->deref_type != nir_deref_type_var) {
          /* The only one system value that is an array and that is
@@ -150,36 +124,167 @@ convert_block(nir_block *block, nir_builder *b)
       }
       nir_variable *var = deref->var;
 
-      b->cursor = nir_after_instr(&load_deref->instr);
-
-      unsigned bit_size = nir_dest_bit_size(load_deref->dest);
-      nir_ssa_def *sysval = NULL;
       switch (var->data.location) {
-      case SYSTEM_VALUE_GLOBAL_INVOCATION_ID: {
-         sysval = build_global_invocation_id(b, bit_size);
-         break;
+      case SYSTEM_VALUE_INSTANCE_INDEX:
+         return nir_iadd(b, nir_load_instance_id(b),
+                            nir_load_base_instance(b));
+
+      case SYSTEM_VALUE_SUBGROUP_EQ_MASK:
+      case SYSTEM_VALUE_SUBGROUP_GE_MASK:
+      case SYSTEM_VALUE_SUBGROUP_GT_MASK:
+      case SYSTEM_VALUE_SUBGROUP_LE_MASK:
+      case SYSTEM_VALUE_SUBGROUP_LT_MASK: {
+         nir_intrinsic_op op =
+            nir_intrinsic_from_system_value(var->data.location);
+         nir_intrinsic_instr *load = nir_intrinsic_instr_create(b->shader, op);
+         nir_ssa_dest_init_for_type(&load->instr, &load->dest,
+                                    var->type, NULL);
+         load->num_components = load->dest.ssa.num_components;
+         nir_builder_instr_insert(b, &load->instr);
+         return &load->dest.ssa;
       }
 
-      case SYSTEM_VALUE_GLOBAL_INVOCATION_INDEX: {
-         nir_ssa_def *global_id = build_global_invocation_id(b, bit_size);
-         nir_ssa_def *global_size = build_global_group_size(b, bit_size);
+      case SYSTEM_VALUE_DEVICE_INDEX:
+         if (b->shader->options->lower_device_index_to_zero)
+            return nir_imm_int(b, 0);
+         break;
+
+      case SYSTEM_VALUE_GLOBAL_GROUP_SIZE:
+         return build_global_group_size(b, bit_size);
+
+      case SYSTEM_VALUE_BARYCENTRIC_LINEAR_PIXEL:
+         return nir_load_barycentric(b, nir_intrinsic_load_barycentric_pixel,
+                                     INTERP_MODE_NOPERSPECTIVE);
+
+      case SYSTEM_VALUE_BARYCENTRIC_LINEAR_CENTROID:
+         return nir_load_barycentric(b, nir_intrinsic_load_barycentric_centroid,
+                                     INTERP_MODE_NOPERSPECTIVE);
+
+      case SYSTEM_VALUE_BARYCENTRIC_LINEAR_SAMPLE:
+         return nir_load_barycentric(b, nir_intrinsic_load_barycentric_sample,
+                                     INTERP_MODE_NOPERSPECTIVE);
 
-         /* index = id.x + ((id.y + (id.z * size.y)) * size.x) */
-         sysval = nir_imul(b, nir_channel(b, global_id, 2),
-                              nir_channel(b, global_size, 1));
-         sysval = nir_iadd(b, nir_channel(b, global_id, 1), sysval);
-         sysval = nir_imul(b, nir_channel(b, global_size, 0), sysval);
-         sysval = nir_iadd(b, nir_channel(b, global_id, 0), sysval);
+      case SYSTEM_VALUE_BARYCENTRIC_PERSP_PIXEL:
+         return nir_load_barycentric(b, nir_intrinsic_load_barycentric_pixel,
+                                     INTERP_MODE_SMOOTH);
+
+      case SYSTEM_VALUE_BARYCENTRIC_PERSP_CENTROID:
+         return nir_load_barycentric(b, nir_intrinsic_load_barycentric_centroid,
+                                     INTERP_MODE_SMOOTH);
+
+      case SYSTEM_VALUE_BARYCENTRIC_PERSP_SAMPLE:
+         return nir_load_barycentric(b, nir_intrinsic_load_barycentric_sample,
+                                     INTERP_MODE_SMOOTH);
+
+      case SYSTEM_VALUE_BARYCENTRIC_PULL_MODEL:
+         return nir_load_barycentric(b, nir_intrinsic_load_barycentric_model,
+                                     INTERP_MODE_NONE);
+
+      default:
          break;
       }
 
-      case SYSTEM_VALUE_LOCAL_INVOCATION_INDEX: {
-         /* If lower_cs_local_index_from_id is true, then we derive the local
-          * index from the local id.
+      nir_intrinsic_op sysval_op =
+         nir_intrinsic_from_system_value(var->data.location);
+      return nir_load_system_value(b, sysval_op, 0,
+                                      intrin->dest.ssa.num_components,
+                                      intrin->dest.ssa.bit_size);
+   }
+
+   default:
+      return NULL;
+   }
+}
+
+bool
+nir_lower_system_values(nir_shader *shader)
+{
+   bool progress = nir_shader_lower_instructions(shader,
+                                                 lower_system_value_filter,
+                                                 lower_system_value_instr,
+                                                 NULL);
+
+   /* We're going to delete the variables so we need to clean up all those
+    * derefs we left lying around.
+    */
+   if (progress)
+      nir_remove_dead_derefs(shader);
+
+   nir_foreach_variable_with_modes_safe(var, shader, nir_var_system_value)
+      exec_node_remove(&var->node);
+
+   return progress;
+}
+
+static bool
+lower_compute_system_value_filter(const nir_instr *instr, const void *_options)
+{
+   return instr->type == nir_instr_type_intrinsic;
+}
+
+static nir_ssa_def *
+lower_compute_system_value_instr(nir_builder *b,
+                                 nir_instr *instr, void *_options)
+{
+   nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+   const nir_lower_compute_system_values_options *options = _options;
+
+   /* All the intrinsics we care about are loads */
+   if (!nir_intrinsic_infos[intrin->intrinsic].has_dest)
+      return NULL;
+
+   assert(intrin->dest.is_ssa);
+   const unsigned bit_size = intrin->dest.ssa.bit_size;
+
+   switch (intrin->intrinsic) {
+   case nir_intrinsic_load_local_invocation_id:
+      /* If lower_cs_local_id_from_index is true, then we derive the local
+       * index from the local id.
+       */
+      if (b->shader->options->lower_cs_local_id_from_index) {
+         /* We lower gl_LocalInvocationID from gl_LocalInvocationIndex based
+          * on this formula:
+          *
+          *    gl_LocalInvocationID.x =
+          *       gl_LocalInvocationIndex % gl_WorkGroupSize.x;
+          *    gl_LocalInvocationID.y =
+          *       (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
+          *       gl_WorkGroupSize.y;
+          *    gl_LocalInvocationID.z =
+          *       (gl_LocalInvocationIndex /
+          *        (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
+          *       gl_WorkGroupSize.z;
+          *
+          * However, the final % gl_WorkGroupSize.z does nothing unless we
+          * accidentally end up with a gl_LocalInvocationIndex that is too
+          * large so it can safely be omitted.
+          */
+         nir_ssa_def *local_index = nir_load_local_invocation_index(b);
+         nir_ssa_def *local_size = nir_load_local_group_size(b);
+
+         /* Because no hardware supports a local workgroup size greater than
+          * about 1K, this calculation can be done in 32-bit and can save some
+          * 64-bit arithmetic.
           */
-         if (!b->shader->options->lower_cs_local_index_from_id)
-            break;
+         nir_ssa_def *id_x, *id_y, *id_z;
+         id_x = nir_umod(b, local_index,
+                            nir_channel(b, local_size, 0));
+         id_y = nir_umod(b, nir_udiv(b, local_index,
+                                        nir_channel(b, local_size, 0)),
+                            nir_channel(b, local_size, 1));
+         id_z = nir_udiv(b, local_index,
+                            nir_imul(b, nir_channel(b, local_size, 0),
+                                        nir_channel(b, local_size, 1)));
+         return nir_u2u(b, nir_vec3(b, id_x, id_y, id_z), bit_size);
+      } else {
+         return NULL;
+      }
 
+   case nir_intrinsic_load_local_invocation_index:
+      /* If lower_cs_local_index_from_id is true, then we derive the local
+       * index from the local id.
+       */
+      if (b->shader->options->lower_cs_local_index_from_id) {
          /* From the GLSL man page for gl_LocalInvocationIndex:
           *
           *    "The value of gl_LocalInvocationIndex is equal to
@@ -198,150 +303,100 @@ convert_block(nir_block *block, nir_builder *b)
           * about 1K, this calculation can be done in 32-bit and can save some
           * 64-bit arithmetic.
           */
-         sysval = nir_imul(b, nir_channel(b, local_id, 2),
-                              nir_imul(b, size_x, size_y));
-         sysval = nir_iadd(b, sysval,
-                              nir_imul(b, nir_channel(b, local_id, 1), size_x));
-         sysval = nir_iadd(b, sysval, nir_channel(b, local_id, 0));
-         sysval = nir_u2u(b, sysval, bit_size);
-         break;
-      }
-
-      case SYSTEM_VALUE_LOCAL_INVOCATION_ID:
-         sysval = build_local_invocation_id(b, bit_size);
-         break;
-
-      case SYSTEM_VALUE_LOCAL_GROUP_SIZE: {
-         sysval = build_local_group_size(b, bit_size);
-         break;
+         nir_ssa_def *index;
+         index = nir_imul(b, nir_channel(b, local_id, 2),
+                             nir_imul(b, size_x, size_y));
+         index = nir_iadd(b, index,
+                             nir_imul(b, nir_channel(b, local_id, 1), size_x));
+         index = nir_iadd(b, index, nir_channel(b, local_id, 0));
+         return nir_u2u(b, index, bit_size);
+      } else {
+         return NULL;
       }
 
-      case SYSTEM_VALUE_VERTEX_ID:
-         if (b->shader->options->vertex_id_zero_based) {
-            sysval = nir_iadd(b,
-                              nir_load_vertex_id_zero_base(b),
-                              nir_load_first_vertex(b));
-         } else {
-            sysval = nir_load_vertex_id(b);
-         }
-         break;
-
-      case SYSTEM_VALUE_BASE_VERTEX:
-         /**
-          * From the OpenGL 4.6 (11.1.3.9 Shader Inputs) specification:
-          *
-          * "gl_BaseVertex holds the integer value passed to the baseVertex
-          * parameter to the command that resulted in the current shader
-          * invocation. In the case where the command has no baseVertex
-          * parameter, the value of gl_BaseVertex is zero."
+   case nir_intrinsic_load_local_group_size:
+      if (b->shader->info.cs.local_size_variable) {
+         /* If the local work group size is variable it can't be lowered at
+          * this point.  We do, however, have to make sure that the intrinsic
+          * is only 32-bit.
           */
-         if (b->shader->options->lower_base_vertex)
-            sysval = nir_iand(b,
-                              nir_load_is_indexed_draw(b),
-                              nir_load_first_vertex(b));
-         break;
-
-      case SYSTEM_VALUE_HELPER_INVOCATION:
-         if (b->shader->options->lower_helper_invocation) {
-            nir_ssa_def *tmp;
-
-            tmp = nir_ishl(b,
-                           nir_imm_int(b, 1),
-                           nir_load_sample_id_no_per_sample(b));
-
-            tmp = nir_iand(b,
-                           nir_load_sample_mask_in(b),
-                           tmp);
-
-            sysval = nir_inot(b, nir_i2b(b, tmp));
-         }
-
-         break;
-
-      case SYSTEM_VALUE_INSTANCE_INDEX:
-         sysval = nir_iadd(b,
-                           nir_load_instance_id(b),
-                           nir_load_base_instance(b));
-         break;
-
-      case SYSTEM_VALUE_SUBGROUP_EQ_MASK:
-      case SYSTEM_VALUE_SUBGROUP_GE_MASK:
-      case SYSTEM_VALUE_SUBGROUP_GT_MASK:
-      case SYSTEM_VALUE_SUBGROUP_LE_MASK:
-      case SYSTEM_VALUE_SUBGROUP_LT_MASK: {
-         nir_intrinsic_op op =
-            nir_intrinsic_from_system_value(var->data.location);
-         nir_intrinsic_instr *load = nir_intrinsic_instr_create(b->shader, op);
-         nir_ssa_dest_init_for_type(&load->instr, &load->dest,
-                                    var->type, NULL);
-         load->num_components = load->dest.ssa.num_components;
-         nir_builder_instr_insert(b, &load->instr);
-         sysval = &load->dest.ssa;
-         break;
-      }
-
-      case SYSTEM_VALUE_DEVICE_INDEX:
-         if (b->shader->options->lower_device_index_to_zero)
-            sysval = nir_imm_int(b, 0);
-         break;
-
-      case SYSTEM_VALUE_GLOBAL_GROUP_SIZE: {
-         sysval = build_global_group_size(b, bit_size);
-         break;
+         return NULL;
+      } else {
+         /* using a 32 bit constant is safe here as no device/driver needs more
+          * than 32 bits for the local size */
+         nir_const_value local_size_const[3];
+         memset(local_size_const, 0, sizeof(local_size_const));
+         local_size_const[0].u32 = b->shader->info.cs.local_size[0];
+         local_size_const[1].u32 = b->shader->info.cs.local_size[1];
+         local_size_const[2].u32 = b->shader->info.cs.local_size[2];
+         return nir_u2u(b, nir_build_imm(b, 3, 32, local_size_const), bit_size);
       }
 
-      default:
-         break;
-      }
+   case nir_intrinsic_load_global_invocation_id_zero_base: {
+      if ((options && options->has_base_work_group_id) ||
+          !b->shader->options->has_cs_global_id) {
+         nir_ssa_def *group_size = nir_load_local_group_size(b);
+         nir_ssa_def *group_id = nir_load_work_group_id(b, bit_size);
+         nir_ssa_def *local_id = nir_load_local_invocation_id(b);
 
-      if (sysval == NULL) {
-         nir_intrinsic_op sysval_op =
-            nir_intrinsic_from_system_value(var->data.location);
-         sysval = nir_load_system_value(b, sysval_op, 0,
-                                        load_deref->dest.ssa.bit_size);
+         return nir_iadd(b, nir_imul(b, group_id,
+                                        nir_u2u(b, group_size, bit_size)),
+                            nir_u2u(b, local_id, bit_size));
+      } else {
+         return NULL;
       }
-
-      nir_ssa_def_rewrite_uses(&load_deref->dest.ssa, nir_src_for_ssa(sysval));
-      nir_instr_remove(&load_deref->instr);
-
-      progress = true;
    }
 
-   return progress;
-}
+   case nir_intrinsic_load_global_invocation_id: {
+      if (options && options->has_base_global_invocation_id)
+         return nir_iadd(b, nir_load_global_invocation_id_zero_base(b, bit_size),
+                            nir_load_base_global_invocation_id(b, bit_size));
+      else if (!b->shader->options->has_cs_global_id)
+         return nir_load_global_invocation_id_zero_base(b, bit_size);
+      else
+         return NULL;
+   }
 
-static bool
-convert_impl(nir_function_impl *impl)
-{
-   bool progress = false;
-   nir_builder builder;
-   nir_builder_init(&builder, impl);
+   case nir_intrinsic_load_global_invocation_index: {
+      /* OpenCL's global_linear_id explicitly removes the global offset before computing this */
+      assert(b->shader->info.stage == MESA_SHADER_KERNEL);
+      nir_ssa_def *global_base_id = nir_load_base_global_invocation_id(b, bit_size);
+      nir_ssa_def *global_id = nir_isub(b, nir_load_global_invocation_id(b, bit_size), global_base_id);
+      nir_ssa_def *global_size = build_global_group_size(b, bit_size);
+
+      /* index = id.x + ((id.y + (id.z * size.y)) * size.x) */
+      nir_ssa_def *index;
+      index = nir_imul(b, nir_channel(b, global_id, 2),
+                          nir_channel(b, global_size, 1));
+      index = nir_iadd(b, nir_channel(b, global_id, 1), index);
+      index = nir_imul(b, nir_channel(b, global_size, 0), index);
+      index = nir_iadd(b, nir_channel(b, global_id, 0), index);
+      return index;
+   }
 
-   nir_foreach_block(block, impl) {
-      progress |= convert_block(block, &builder);
+   case nir_intrinsic_load_work_group_id: {
+      if (options && options->has_base_work_group_id)
+         return nir_iadd(b, nir_u2u(b, nir_load_work_group_id_zero_base(b), bit_size),
+                            nir_load_base_work_group_id(b, bit_size));
+      else
+         return NULL;
    }
 
-   nir_metadata_preserve(impl, nir_metadata_block_index |
-                               nir_metadata_dominance);
-   return progress;
+   default:
+      return NULL;
+   }
 }
 
 bool
-nir_lower_system_values(nir_shader *shader)
+nir_lower_compute_system_values(nir_shader *shader,
+                                const nir_lower_compute_system_values_options *options)
 {
-   bool progress = false;
-
-   nir_foreach_function(function, shader) {
-      if (function->impl)
-         progress = convert_impl(function->impl) || progress;
-   }
-
-   /* We're going to delete the variables so we need to clean up all those
-    * derefs we left lying around.
-    */
-   nir_remove_dead_derefs(shader);
-
-   exec_list_make_empty(&shader->system_values);
-
-   return progress;
+   if (shader->info.stage != MESA_SHADER_COMPUTE &&
+       shader->info.stage != MESA_SHADER_KERNEL)
+      return false;
+
+   return nir_shader_lower_instructions(shader,
+                                        lower_compute_system_value_filter,
+                                        lower_compute_system_value_instr,
+                                        (void*)options);
 }