nir: Convert lower_io to deref instructions
[mesa.git] / src / compiler / nir / nir_lower_io.c
index c25790a6c3c72059c46a4aa2808e00c15de80b0c..3bdacee66bfd312ba4538afa8acfa31a7e3f3842 100644 (file)
 
 #include "nir.h"
 #include "nir_builder.h"
+#include "nir_deref.h"
 
 struct lower_io_state {
+   void *dead_ctx;
    nir_builder builder;
-   void *mem_ctx;
    int (*type_size)(const struct glsl_type *type);
    nir_variable_mode modes;
+   nir_lower_io_options options;
 };
 
 void
 nir_assign_var_locations(struct exec_list *var_list, unsigned *size,
-                         unsigned base_offset,
                          int (*type_size)(const struct glsl_type *))
 {
    unsigned location = 0;
 
-   /* There are 32 regular and 32 patch varyings allowed */
-   int locations[64][2];
-   for (unsigned i = 0; i < 64; i++) {
-      for (unsigned j = 0; j < 2; j++)
-         locations[i][j] = -1;
-   }
-
    nir_foreach_variable(var, var_list) {
       /*
-       * UBO's have their own address spaces, so don't count them towards the
+       * UBOs have their own address spaces, so don't count them towards the
        * number of global uniforms
        */
       if ((var->data.mode == nir_var_uniform || var->data.mode == nir_var_shader_storage) &&
           var->interface_type != NULL)
          continue;
 
-      /* Make sure we give the same location to varyings packed with
-       * ARB_enhanced_layouts.
-       */
-      int idx = var->data.location - base_offset;
-      if (base_offset && idx >= 0) {
-         assert(idx < ARRAY_SIZE(locations));
-
-         if (locations[idx][var->data.index] == -1) {
-            var->data.driver_location = location;
-            locations[idx][var->data.index] = location;
-            location += type_size(var->type);
-         } else {
-            var->data.driver_location = locations[idx][var->data.index];
-         }
-      } else {
-         var->data.driver_location = location;
-         location += type_size(var->type);
-      }
+      var->data.driver_location = location;
+      location += type_size(var->type);
    }
 
    *size = location;
 }
 
 /**
- * Returns true if we're processing a stage whose inputs are arrays indexed
- * by a vertex number (such as geometry shader inputs).
+ * Return true if the given variable is a per-vertex input/output array.
+ * (such as geometry shader inputs).
  */
-static bool
-is_per_vertex_input(struct lower_io_state *state, nir_variable *var)
+bool
+nir_is_per_vertex_io(const nir_variable *var, gl_shader_stage stage)
 {
-   gl_shader_stage stage = state->builder.shader->stage;
+   if (var->data.patch || !glsl_type_is_array(var->type))
+      return false;
 
-   return var->data.mode == nir_var_shader_in && !var->data.patch &&
-          (stage == MESA_SHADER_TESS_CTRL ||
-           stage == MESA_SHADER_TESS_EVAL ||
-           stage == MESA_SHADER_GEOMETRY);
-}
+   if (var->data.mode == nir_var_shader_in)
+      return stage == MESA_SHADER_GEOMETRY ||
+             stage == MESA_SHADER_TESS_CTRL ||
+             stage == MESA_SHADER_TESS_EVAL;
 
-static bool
-is_per_vertex_output(struct lower_io_state *state, nir_variable *var)
-{
-   gl_shader_stage stage = state->builder.shader->stage;
-   return var->data.mode == nir_var_shader_out && !var->data.patch &&
-          stage == MESA_SHADER_TESS_CTRL;
+   if (var->data.mode == nir_var_shader_out)
+      return stage == MESA_SHADER_TESS_CTRL;
+
+   return false;
 }
 
 static nir_ssa_def *
-get_io_offset(nir_builder *b, nir_deref_var *deref,
+get_io_offset(nir_builder *b, nir_deref_instr *deref,
               nir_ssa_def **vertex_index,
-              int (*type_size)(const struct glsl_type *))
+              int (*type_size)(const struct glsl_type *),
+              unsigned *component)
 {
-   nir_deref *tail = &deref->deref;
+   nir_deref_path path;
+   nir_deref_path_init(&path, deref, NULL);
+
+   assert(path.path[0]->deref_type == nir_deref_type_var);
+   nir_deref_instr **p = &path.path[1];
 
    /* For per-vertex input arrays (i.e. geometry shader inputs), keep the
     * outermost array index separate.  Process the rest normally.
     */
    if (vertex_index != NULL) {
-      tail = tail->child;
-      assert(tail->deref_type == nir_deref_type_array);
-      nir_deref_array *deref_array = nir_deref_as_array(tail);
+      assert((*p)->deref_type == nir_deref_type_array);
+      *vertex_index = nir_ssa_for_src(b, (*p)->arr.index, 1);
+      p++;
+   }
 
-      nir_ssa_def *vtx = nir_imm_int(b, deref_array->base_offset);
-      if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
-         vtx = nir_iadd(b, vtx, nir_ssa_for_src(b, deref_array->indirect, 1));
-      }
-      *vertex_index = vtx;
+   if (path.path[0]->var->data.compact) {
+      assert((*p)->deref_type == nir_deref_type_array);
+      assert(glsl_type_is_scalar((*p)->type));
+
+      /* We always lower indirect dereferences for "compact" array vars. */
+      nir_const_value *const_index = nir_src_as_const_value((*p)->arr.index);
+      assert(const_index);
+
+      const unsigned total_offset = *component + const_index->u32[0];
+      const unsigned slot_offset = total_offset / 4;
+      *component = total_offset % 4;
+      return nir_imm_int(b, type_size(glsl_vec4_type()) * slot_offset);
    }
 
    /* Just emit code and let constant-folding go to town */
    nir_ssa_def *offset = nir_imm_int(b, 0);
 
-   while (tail->child != NULL) {
-      const struct glsl_type *parent_type = tail->type;
-      tail = tail->child;
+   for (; *p; p++) {
+      if ((*p)->deref_type == nir_deref_type_array) {
+         unsigned size = type_size((*p)->type);
 
-      if (tail->deref_type == nir_deref_type_array) {
-         nir_deref_array *deref_array = nir_deref_as_array(tail);
-         unsigned size = type_size(tail->type);
+         nir_ssa_def *mul =
+            nir_imul(b, nir_imm_int(b, size),
+                     nir_ssa_for_src(b, (*p)->arr.index, 1));
 
-         offset = nir_iadd(b, offset,
-                           nir_imm_int(b, size * deref_array->base_offset));
-
-         if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
-            nir_ssa_def *mul =
-               nir_imul(b, nir_imm_int(b, size),
-                        nir_ssa_for_src(b, deref_array->indirect, 1));
-
-            offset = nir_iadd(b, offset, mul);
-         }
-      } else if (tail->deref_type == nir_deref_type_struct) {
-         nir_deref_struct *deref_struct = nir_deref_as_struct(tail);
+         offset = nir_iadd(b, offset, mul);
+      } else if ((*p)->deref_type == nir_deref_type_struct) {
+         /* p starts at path[1], so this is safe */
+         nir_deref_instr *parent = *(p - 1);
 
          unsigned field_offset = 0;
-         for (unsigned i = 0; i < deref_struct->index; i++) {
-            field_offset += type_size(glsl_get_struct_field(parent_type, i));
+         for (unsigned i = 0; i < (*p)->strct.index; i++) {
+            field_offset += type_size(glsl_get_struct_field(parent->type, i));
          }
          offset = nir_iadd(b, offset, nir_imm_int(b, field_offset));
+      } else {
+         unreachable("Unsupported deref type");
       }
    }
 
+   nir_deref_path_finish(&path);
+
    return offset;
 }
 
-static nir_intrinsic_op
-load_op(nir_variable_mode mode, bool per_vertex)
+static nir_intrinsic_instr *
+lower_load(nir_intrinsic_instr *intrin, struct lower_io_state *state,
+           nir_ssa_def *vertex_index, nir_variable *var, nir_ssa_def *offset,
+           unsigned component)
 {
+   const nir_shader *nir = state->builder.shader;
+   nir_variable_mode mode = var->data.mode;
+   nir_ssa_def *barycentric = NULL;
+
    nir_intrinsic_op op;
    switch (mode) {
    case nir_var_shader_in:
-      op = per_vertex ? nir_intrinsic_load_per_vertex_input :
-                        nir_intrinsic_load_input;
+      if (nir->info.stage == MESA_SHADER_FRAGMENT &&
+          nir->options->use_interpolated_input_intrinsics &&
+          var->data.interpolation != INTERP_MODE_FLAT) {
+         assert(vertex_index == NULL);
+
+         nir_intrinsic_op bary_op;
+         if (var->data.sample ||
+             (state->options & nir_lower_io_force_sample_interpolation))
+            bary_op = nir_intrinsic_load_barycentric_sample;
+         else if (var->data.centroid)
+            bary_op = nir_intrinsic_load_barycentric_centroid;
+         else
+            bary_op = nir_intrinsic_load_barycentric_pixel;
+
+         barycentric = nir_load_barycentric(&state->builder, bary_op,
+                                            var->data.interpolation);
+         op = nir_intrinsic_load_interpolated_input;
+      } else {
+         op = vertex_index ? nir_intrinsic_load_per_vertex_input :
+                             nir_intrinsic_load_input;
+      }
       break;
    case nir_var_shader_out:
-      op = per_vertex ? nir_intrinsic_load_per_vertex_output :
-                        nir_intrinsic_load_output;
+      op = vertex_index ? nir_intrinsic_load_per_vertex_output :
+                          nir_intrinsic_load_output;
       break;
    case nir_var_uniform:
       op = nir_intrinsic_load_uniform;
@@ -189,34 +199,77 @@ load_op(nir_variable_mode mode, bool per_vertex)
    default:
       unreachable("Unknown variable mode");
    }
-   return op;
+
+   nir_intrinsic_instr *load =
+      nir_intrinsic_instr_create(state->builder.shader, op);
+   load->num_components = intrin->num_components;
+
+   nir_intrinsic_set_base(load, var->data.driver_location);
+   if (mode == nir_var_shader_in || mode == nir_var_shader_out)
+      nir_intrinsic_set_component(load, component);
+
+   if (load->intrinsic == nir_intrinsic_load_uniform)
+      nir_intrinsic_set_range(load, state->type_size(var->type));
+
+   if (vertex_index) {
+      load->src[0] = nir_src_for_ssa(vertex_index);
+      load->src[1] = nir_src_for_ssa(offset);
+   } else if (barycentric) {
+      load->src[0] = nir_src_for_ssa(barycentric);
+      load->src[1] = nir_src_for_ssa(offset);
+   } else {
+      load->src[0] = nir_src_for_ssa(offset);
+   }
+
+   return load;
 }
 
-static nir_intrinsic_op
-store_op(struct lower_io_state *state,
-         nir_variable_mode mode, bool per_vertex)
+static nir_intrinsic_instr *
+lower_store(nir_intrinsic_instr *intrin, struct lower_io_state *state,
+            nir_ssa_def *vertex_index, nir_variable *var, nir_ssa_def *offset,
+            unsigned component)
 {
+   nir_variable_mode mode = var->data.mode;
+
    nir_intrinsic_op op;
-   switch (mode) {
-   case nir_var_shader_in:
-   case nir_var_shader_out:
-      op = per_vertex ? nir_intrinsic_store_per_vertex_output :
-                        nir_intrinsic_store_output;
-      break;
-   case nir_var_shared:
+   if (mode == nir_var_shared) {
       op = nir_intrinsic_store_shared;
-      break;
-   default:
-      unreachable("Unknown variable mode");
+   } else {
+      assert(mode == nir_var_shader_out);
+      op = vertex_index ? nir_intrinsic_store_per_vertex_output :
+                          nir_intrinsic_store_output;
    }
-   return op;
+
+   nir_intrinsic_instr *store =
+      nir_intrinsic_instr_create(state->builder.shader, op);
+   store->num_components = intrin->num_components;
+
+   nir_src_copy(&store->src[0], &intrin->src[1], store);
+
+   nir_intrinsic_set_base(store, var->data.driver_location);
+
+   if (mode == nir_var_shader_out)
+      nir_intrinsic_set_component(store, component);
+
+   nir_intrinsic_set_write_mask(store, nir_intrinsic_write_mask(intrin));
+
+   if (vertex_index)
+      store->src[1] = nir_src_for_ssa(vertex_index);
+
+   store->src[vertex_index ? 2 : 1] = nir_src_for_ssa(offset);
+
+   return store;
 }
 
-static nir_intrinsic_op
-atomic_op(nir_intrinsic_op opcode)
+static nir_intrinsic_instr *
+lower_atomic(nir_intrinsic_instr *intrin, struct lower_io_state *state,
+             nir_variable *var, nir_ssa_def *offset)
 {
-   switch (opcode) {
-#define OP(O) case nir_intrinsic_var_##O: return nir_intrinsic_shared_##O;
+   assert(var->data.mode == nir_var_shared);
+
+   nir_intrinsic_op op;
+   switch (intrin->intrinsic) {
+#define OP(O) case nir_intrinsic_deref_##O: op = nir_intrinsic_shared_##O; break;
    OP(atomic_exchange)
    OP(atomic_comp_swap)
    OP(atomic_add)
@@ -231,6 +284,73 @@ atomic_op(nir_intrinsic_op opcode)
    default:
       unreachable("Invalid atomic");
    }
+
+   nir_intrinsic_instr *atomic =
+      nir_intrinsic_instr_create(state->builder.shader, op);
+
+   nir_intrinsic_set_base(atomic, var->data.driver_location);
+
+   atomic->src[0] = nir_src_for_ssa(offset);
+   assert(nir_intrinsic_infos[intrin->intrinsic].num_srcs ==
+          nir_intrinsic_infos[op].num_srcs);
+   for (unsigned i = 1; i < nir_intrinsic_infos[op].num_srcs; i++) {
+      nir_src_copy(&atomic->src[i], &intrin->src[i], atomic);
+   }
+
+   return atomic;
+}
+
+static nir_intrinsic_instr *
+lower_interpolate_at(nir_intrinsic_instr *intrin, struct lower_io_state *state,
+                     nir_variable *var, nir_ssa_def *offset, unsigned component)
+{
+   assert(var->data.mode == nir_var_shader_in);
+
+   /* Ignore interpolateAt() for flat variables - flat is flat. */
+   if (var->data.interpolation == INTERP_MODE_FLAT)
+      return lower_load(intrin, state, NULL, var, offset, component);
+
+   nir_intrinsic_op bary_op;
+   switch (intrin->intrinsic) {
+   case nir_intrinsic_interp_deref_at_centroid:
+      bary_op = (state->options & nir_lower_io_force_sample_interpolation) ?
+                nir_intrinsic_load_barycentric_sample :
+                nir_intrinsic_load_barycentric_centroid;
+      break;
+   case nir_intrinsic_interp_deref_at_sample:
+      bary_op = nir_intrinsic_load_barycentric_at_sample;
+      break;
+   case nir_intrinsic_interp_deref_at_offset:
+      bary_op = nir_intrinsic_load_barycentric_at_offset;
+      break;
+   default:
+      unreachable("Bogus interpolateAt() intrinsic.");
+   }
+
+   nir_intrinsic_instr *bary_setup =
+      nir_intrinsic_instr_create(state->builder.shader, bary_op);
+
+   nir_ssa_dest_init(&bary_setup->instr, &bary_setup->dest, 2, 32, NULL);
+   nir_intrinsic_set_interp_mode(bary_setup, var->data.interpolation);
+
+   if (intrin->intrinsic == nir_intrinsic_interp_deref_at_sample ||
+       intrin->intrinsic == nir_intrinsic_interp_deref_at_offset)
+      nir_src_copy(&bary_setup->src[0], &intrin->src[1], bary_setup);
+
+   nir_builder_instr_insert(&state->builder, &bary_setup->instr);
+
+   nir_intrinsic_instr *load =
+      nir_intrinsic_instr_create(state->builder.shader,
+                                 nir_intrinsic_load_interpolated_input);
+   load->num_components = intrin->num_components;
+
+   nir_intrinsic_set_base(load, var->data.driver_location);
+   nir_intrinsic_set_component(load, component);
+
+   load->src[0] = nir_src_for_ssa(&bary_setup->dest.ssa);
+   load->src[1] = nir_src_for_ssa(offset);
+
+   return load;
 }
 
 static bool
@@ -238,6 +358,8 @@ nir_lower_io_block(nir_block *block,
                    struct lower_io_state *state)
 {
    nir_builder *b = &state->builder;
+   const nir_shader_compiler_options *options = b->shader->options;
+   bool progress = false;
 
    nir_foreach_instr_safe(instr, block) {
       if (instr->type != nir_instr_type_intrinsic)
@@ -246,26 +368,35 @@ nir_lower_io_block(nir_block *block,
       nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
 
       switch (intrin->intrinsic) {
-      case nir_intrinsic_load_var:
-      case nir_intrinsic_store_var:
-      case nir_intrinsic_var_atomic_add:
-      case nir_intrinsic_var_atomic_imin:
-      case nir_intrinsic_var_atomic_umin:
-      case nir_intrinsic_var_atomic_imax:
-      case nir_intrinsic_var_atomic_umax:
-      case nir_intrinsic_var_atomic_and:
-      case nir_intrinsic_var_atomic_or:
-      case nir_intrinsic_var_atomic_xor:
-      case nir_intrinsic_var_atomic_exchange:
-      case nir_intrinsic_var_atomic_comp_swap:
+      case nir_intrinsic_load_deref:
+      case nir_intrinsic_store_deref:
+      case nir_intrinsic_deref_atomic_add:
+      case nir_intrinsic_deref_atomic_imin:
+      case nir_intrinsic_deref_atomic_umin:
+      case nir_intrinsic_deref_atomic_imax:
+      case nir_intrinsic_deref_atomic_umax:
+      case nir_intrinsic_deref_atomic_and:
+      case nir_intrinsic_deref_atomic_or:
+      case nir_intrinsic_deref_atomic_xor:
+      case nir_intrinsic_deref_atomic_exchange:
+      case nir_intrinsic_deref_atomic_comp_swap:
          /* We can lower the io for this nir instrinsic */
          break;
+      case nir_intrinsic_interp_deref_at_centroid:
+      case nir_intrinsic_interp_deref_at_sample:
+      case nir_intrinsic_interp_deref_at_offset:
+         /* We can optionally lower these to load_interpolated_input */
+         if (options->use_interpolated_input_intrinsics)
+            break;
       default:
          /* We can't lower the io for this nir instrinsic, so skip it */
          continue;
       }
 
-      nir_variable_mode mode = intrin->variables[0]->var->data.mode;
+      nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
+
+      nir_variable *var = nir_deref_instr_get_variable(deref);
+      nir_variable_mode mode = var->data.mode;
 
       if ((state->modes & mode) == 0)
          continue;
@@ -278,181 +409,121 @@ nir_lower_io_block(nir_block *block,
 
       b->cursor = nir_before_instr(instr);
 
-      switch (intrin->intrinsic) {
-      case nir_intrinsic_load_var: {
-         bool per_vertex =
-            is_per_vertex_input(state, intrin->variables[0]->var) ||
-            is_per_vertex_output(state, intrin->variables[0]->var);
-
-         nir_ssa_def *offset;
-         nir_ssa_def *vertex_index;
-
-         offset = get_io_offset(b, intrin->variables[0],
-                                per_vertex ? &vertex_index : NULL,
-                                state->type_size);
-
-         nir_intrinsic_instr *load =
-            nir_intrinsic_instr_create(state->mem_ctx,
-                                       load_op(mode, per_vertex));
-         load->num_components = intrin->num_components;
-
-         nir_intrinsic_set_base(load,
-            intrin->variables[0]->var->data.driver_location);
-         if (mode == nir_var_shader_in || mode == nir_var_shader_out) {
-            nir_intrinsic_set_component(load,
-               intrin->variables[0]->var->data.location_frac);
-         }
-
-         if (load->intrinsic == nir_intrinsic_load_uniform) {
-            nir_intrinsic_set_range(load,
-               state->type_size(intrin->variables[0]->var->type));
-         }
+      const bool per_vertex = nir_is_per_vertex_io(var, b->shader->info.stage);
 
-         if (per_vertex)
-            load->src[0] = nir_src_for_ssa(vertex_index);
+      nir_ssa_def *offset;
+      nir_ssa_def *vertex_index = NULL;
+      unsigned component_offset = var->data.location_frac;
 
-         load->src[per_vertex ? 1 : 0] = nir_src_for_ssa(offset);
+      offset = get_io_offset(b, deref, per_vertex ? &vertex_index : NULL,
+                             state->type_size, &component_offset);
 
-         if (intrin->dest.is_ssa) {
-            nir_ssa_dest_init(&load->instr, &load->dest,
-                              intrin->num_components,
-                              intrin->dest.ssa.bit_size, NULL);
-            nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
-                                     nir_src_for_ssa(&load->dest.ssa));
-         } else {
-            nir_dest_copy(&load->dest, &intrin->dest, state->mem_ctx);
-         }
+      nir_intrinsic_instr *replacement;
 
-         nir_instr_insert_before(&intrin->instr, &load->instr);
-         nir_instr_remove(&intrin->instr);
+      switch (intrin->intrinsic) {
+      case nir_intrinsic_load_deref:
+         replacement = lower_load(intrin, state, vertex_index, var, offset,
+                                  component_offset);
          break;
-      }
-
-      case nir_intrinsic_store_var: {
-         assert(mode == nir_var_shader_out || mode == nir_var_shared);
-
-         nir_ssa_def *offset;
-         nir_ssa_def *vertex_index;
-
-         bool per_vertex =
-            is_per_vertex_output(state, intrin->variables[0]->var);
-
-         offset = get_io_offset(b, intrin->variables[0],
-                                per_vertex ? &vertex_index : NULL,
-                                state->type_size);
-
-         nir_intrinsic_instr *store =
-            nir_intrinsic_instr_create(state->mem_ctx,
-                                       store_op(state, mode, per_vertex));
-         store->num_components = intrin->num_components;
 
-         nir_src_copy(&store->src[0], &intrin->src[0], store);
-
-         nir_intrinsic_set_base(store,
-            intrin->variables[0]->var->data.driver_location);
-         if (mode == nir_var_shader_out) {
-            nir_intrinsic_set_component(store,
-               intrin->variables[0]->var->data.location_frac);
-         }
-         nir_intrinsic_set_write_mask(store, nir_intrinsic_write_mask(intrin));
-
-         if (per_vertex)
-            store->src[1] = nir_src_for_ssa(vertex_index);
-
-         store->src[per_vertex ? 2 : 1] = nir_src_for_ssa(offset);
-
-         nir_instr_insert_before(&intrin->instr, &store->instr);
-         nir_instr_remove(&intrin->instr);
+      case nir_intrinsic_store_deref:
+         replacement = lower_store(intrin, state, vertex_index, var, offset,
+                                   component_offset);
          break;
-      }
-
-      case nir_intrinsic_var_atomic_add:
-      case nir_intrinsic_var_atomic_imin:
-      case nir_intrinsic_var_atomic_umin:
-      case nir_intrinsic_var_atomic_imax:
-      case nir_intrinsic_var_atomic_umax:
-      case nir_intrinsic_var_atomic_and:
-      case nir_intrinsic_var_atomic_or:
-      case nir_intrinsic_var_atomic_xor:
-      case nir_intrinsic_var_atomic_exchange:
-      case nir_intrinsic_var_atomic_comp_swap: {
-         assert(mode == nir_var_shared);
 
-         nir_ssa_def *offset;
-
-         offset = get_io_offset(b, intrin->variables[0],
-                                NULL, state->type_size);
-
-         nir_intrinsic_instr *atomic =
-            nir_intrinsic_instr_create(state->mem_ctx,
-                                       atomic_op(intrin->intrinsic));
-
-         atomic->src[0] = nir_src_for_ssa(offset);
+      case nir_intrinsic_deref_atomic_add:
+      case nir_intrinsic_deref_atomic_imin:
+      case nir_intrinsic_deref_atomic_umin:
+      case nir_intrinsic_deref_atomic_imax:
+      case nir_intrinsic_deref_atomic_umax:
+      case nir_intrinsic_deref_atomic_and:
+      case nir_intrinsic_deref_atomic_or:
+      case nir_intrinsic_deref_atomic_xor:
+      case nir_intrinsic_deref_atomic_exchange:
+      case nir_intrinsic_deref_atomic_comp_swap:
+         assert(vertex_index == NULL);
+         replacement = lower_atomic(intrin, state, var, offset);
+         break;
 
-         atomic->const_index[0] =
-            intrin->variables[0]->var->data.driver_location;
+      case nir_intrinsic_interp_deref_at_centroid:
+      case nir_intrinsic_interp_deref_at_sample:
+      case nir_intrinsic_interp_deref_at_offset:
+         assert(vertex_index == NULL);
+         replacement = lower_interpolate_at(intrin, state, var, offset,
+                                            component_offset);
+         break;
 
-         for (unsigned i = 0;
-              i < nir_op_infos[intrin->intrinsic].num_inputs;
-              i++) {
-            nir_src_copy(&atomic->src[i+1], &intrin->src[i], atomic);
-         }
+      default:
+         continue;
+      }
 
+      if (nir_intrinsic_infos[intrin->intrinsic].has_dest) {
          if (intrin->dest.is_ssa) {
-            nir_ssa_dest_init(&atomic->instr, &atomic->dest,
+            nir_ssa_dest_init(&replacement->instr, &replacement->dest,
                               intrin->dest.ssa.num_components,
                               intrin->dest.ssa.bit_size, NULL);
             nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
-                                     nir_src_for_ssa(&atomic->dest.ssa));
+                                     nir_src_for_ssa(&replacement->dest.ssa));
          } else {
-            nir_dest_copy(&atomic->dest, &intrin->dest, state->mem_ctx);
+            nir_dest_copy(&replacement->dest, &intrin->dest, &intrin->instr);
          }
-
-         nir_instr_insert_before(&intrin->instr, &atomic->instr);
-         nir_instr_remove(&intrin->instr);
-         break;
       }
 
-      default:
-         break;
-      }
+      nir_instr_insert_before(&intrin->instr, &replacement->instr);
+      nir_instr_remove(&intrin->instr);
+      progress = true;
    }
 
-   return true;
+   return progress;
 }
 
-static void
+static bool
 nir_lower_io_impl(nir_function_impl *impl,
                   nir_variable_mode modes,
-                  int (*type_size)(const struct glsl_type *))
+                  int (*type_size)(const struct glsl_type *),
+                  nir_lower_io_options options)
 {
    struct lower_io_state state;
+   bool progress = false;
 
    nir_builder_init(&state.builder, impl);
-   state.mem_ctx = ralloc_parent(impl);
+   state.dead_ctx = ralloc_context(NULL);
    state.modes = modes;
    state.type_size = type_size;
+   state.options = options;
 
    nir_foreach_block(block, impl) {
-      nir_lower_io_block(block, &state);
+      progress |= nir_lower_io_block(block, &state);
    }
 
+   ralloc_free(state.dead_ctx);
+
    nir_metadata_preserve(impl, nir_metadata_block_index |
                                nir_metadata_dominance);
+   return progress;
 }
 
-void
+bool
 nir_lower_io(nir_shader *shader, nir_variable_mode modes,
-             int (*type_size)(const struct glsl_type *))
+             int (*type_size)(const struct glsl_type *),
+             nir_lower_io_options options)
 {
+   bool progress = false;
+
+   nir_assert_unlowered_derefs(shader, nir_lower_load_store_derefs | nir_lower_interp_derefs | nir_lower_atomic_derefs);
+
    nir_foreach_function(function, shader) {
-      if (function->impl)
-         nir_lower_io_impl(function->impl, modes, type_size);
+      if (function->impl) {
+         progress |= nir_lower_io_impl(function->impl, modes,
+                                       type_size, options);
+      }
    }
+
+   return progress;
 }
 
 /**
- * Return the offset soruce for a load/store intrinsic.
+ * Return the offset source for a load/store intrinsic.
  */
 nir_src *
 nir_get_io_offset_src(nir_intrinsic_instr *instr)
@@ -466,6 +537,7 @@ nir_get_io_offset_src(nir_intrinsic_instr *instr)
    case nir_intrinsic_load_ssbo:
    case nir_intrinsic_load_per_vertex_input:
    case nir_intrinsic_load_per_vertex_output:
+   case nir_intrinsic_load_interpolated_input:
    case nir_intrinsic_store_output:
       return &instr->src[1];
    case nir_intrinsic_store_ssbo: