Mesa (main): radv/rt: use derefs for the traversal stack

[GitLab Mirror]

Module: Mesa
Branch: main
Commit: 3750663c72b01d8668c13eed44f40863af588ba4
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=3750663c72b01d8668c13eed44f40863af588ba4

Author: Daniel Schürmann <daniel at schuermann.dev>
Date:   Fri Apr 22 00:29:02 2022 +0200

radv/rt: use derefs for the traversal stack

Reviewed-by: Konstantin Seurer <konstantin.seurer at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17301>

---

 src/amd/vulkan/radv_pipeline_rt.c | 46 +++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 24 deletions(-)

diff --git a/src/amd/vulkan/radv_pipeline_rt.c b/src/amd/vulkan/radv_pipeline_rt.c
index eeb481e30b8..d1d0478fdf6 100644
--- a/src/amd/vulkan/radv_pipeline_rt.c
+++ b/src/amd/vulkan/radv_pipeline_rt.c
@@ -1435,15 +1435,15 @@ build_traversal_shader(struct radv_device *device,
    struct rt_variables vars = create_rt_variables(b.shader, dst_vars->stack_sizes);
    map_rt_variables(var_remap, &vars, dst_vars);
 
-   unsigned stack_entry_size = 4;
    unsigned lanes = device->physical_device->rt_wave_size;
-   unsigned stack_entry_stride = stack_entry_size * lanes;
-   nir_ssa_def *stack_entry_stride_def = nir_imm_int(&b, stack_entry_stride);
-   nir_ssa_def *stack_base =
-      nir_iadd_imm(&b, nir_imul_imm(&b, nir_load_local_invocation_index(&b), stack_entry_size),
-                   b.shader->info.shared_size);
-
-   b.shader->info.shared_size += stack_entry_stride * MAX_STACK_ENTRY_COUNT;
+   unsigned elements = lanes * MAX_STACK_ENTRY_COUNT;
+   nir_variable *stack_var = nir_variable_create(b.shader, nir_var_mem_shared,
+                                                 glsl_array_type(glsl_uint_type(), elements, 0),
+                                                 "trav_stack");
+   nir_deref_instr *stack_deref = nir_build_deref_var(&b, stack_var);
+   nir_deref_instr *stack;
+   nir_ssa_def *stack_idx_stride = nir_imm_int(&b, lanes);
+   nir_ssa_def *stack_idx_base = nir_load_local_invocation_index(&b);
 
    nir_ssa_def *accel_struct = nir_load_var(&b, vars.accel_struct);
 
@@ -1471,14 +1471,15 @@ build_traversal_shader(struct radv_device *device,
       nir_store_var(&b, trav_vars.sbt_offset_and_flags, nir_imm_int(&b, 0), 1);
       nir_store_var(&b, trav_vars.instance_addr, nir_imm_int64(&b, 0), 1);
 
-      nir_store_var(&b, trav_vars.stack, nir_iadd(&b, stack_base, stack_entry_stride_def), 1);
-      nir_store_shared(&b, bvh_root, stack_base, .base = 0, .align_mul = stack_entry_size);
+      nir_store_var(&b, trav_vars.stack, nir_iadd(&b, stack_idx_base, stack_idx_stride), 1);
+      stack = nir_build_deref_array(&b, stack_deref, stack_idx_base);
+      nir_store_deref(&b, stack, bvh_root, 0x1);
 
       nir_store_var(&b, trav_vars.top_stack, nir_imm_int(&b, 0), 1);
 
       nir_push_loop(&b);
 
-      nir_push_if(&b, nir_ieq(&b, nir_load_var(&b, trav_vars.stack), stack_base));
+      nir_push_if(&b, nir_ieq(&b, nir_load_var(&b, trav_vars.stack), stack_idx_base));
       nir_jump(&b, nir_jump_break);
       nir_pop_if(&b, NULL);
 
@@ -1495,10 +1496,10 @@ build_traversal_shader(struct radv_device *device,
       nir_pop_if(&b, NULL);
 
       nir_store_var(&b, trav_vars.stack,
-                    nir_isub(&b, nir_load_var(&b, trav_vars.stack), stack_entry_stride_def), 1);
+                    nir_isub(&b, nir_load_var(&b, trav_vars.stack), stack_idx_stride), 1);
 
-      nir_ssa_def *bvh_node = nir_load_shared(&b, 1, 32, nir_load_var(&b, trav_vars.stack), .base = 0,
-                                              .align_mul = stack_entry_size);
+      stack = nir_build_deref_array(&b, stack_deref, nir_load_var(&b, trav_vars.stack));
+      nir_ssa_def *bvh_node = nir_load_deref(&b, stack);
       nir_ssa_def *bvh_node_type = nir_iand_imm(&b, bvh_node, 7);
 
       bvh_node = nir_iadd(&b, nir_load_var(&b, trav_vars.bvh_base), nir_u2u(&b, bvh_node, 64));
@@ -1548,12 +1549,11 @@ build_traversal_shader(struct radv_device *device,
                              build_addr_to_node(
                                 &b, nir_pack_64_2x32(&b, nir_channels(&b, instance_data, 0x3))),
                              1);
-               nir_store_shared(&b, nir_iand_imm(&b, nir_channel(&b, instance_data, 0), 63),
-                                nir_load_var(&b, trav_vars.stack), .base = 0,
-                                .align_mul = stack_entry_size);
+               stack = nir_build_deref_array(&b, stack_deref, nir_load_var(&b, trav_vars.stack));
+               nir_store_deref(&b, stack, nir_iand_imm(&b, nir_channel(&b, instance_data, 0), 63), 0x1);
+
                nir_store_var(&b, trav_vars.stack,
-                             nir_iadd(&b, nir_load_var(&b, trav_vars.stack), stack_entry_stride_def),
-                             1);
+                             nir_iadd(&b, nir_load_var(&b, trav_vars.stack), stack_idx_stride), 1);
 
                nir_store_var(
                   &b, trav_vars.origin,
@@ -1588,11 +1588,11 @@ build_traversal_shader(struct radv_device *device,
                nir_ssa_def *new_node = nir_channel(&b, result, i);
                nir_push_if(&b, nir_ine_imm(&b, new_node, 0xffffffff));
                {
-                  nir_store_shared(&b, new_node, nir_load_var(&b, trav_vars.stack), .base = 0,
-                                   .align_mul = stack_entry_size);
+                  stack = nir_build_deref_array(&b, stack_deref, nir_load_var(&b, trav_vars.stack));
+                  nir_store_deref(&b, stack, new_node, 0x1);
                   nir_store_var(
                      &b, trav_vars.stack,
-                     nir_iadd(&b, nir_load_var(&b, trav_vars.stack), stack_entry_stride_def), 1);
+                     nir_iadd(&b, nir_load_var(&b, trav_vars.stack), stack_idx_stride), 1);
                }
                nir_pop_if(&b, NULL);
             }
@@ -1646,8 +1646,6 @@ insert_traversal(struct radv_device *device, const VkRayTracingPipelineCreateInf
 {
    struct hash_table *var_remap = _mesa_pointer_hash_table_create(NULL);
    nir_shader *shader = build_traversal_shader(device, pCreateInfo, vars, var_remap);
-   b->shader->info.shared_size += shader->info.shared_size;
-   assert(b->shader->info.shared_size <= 32768);
 
    /* For now, just inline the traversal shader */
    nir_push_if(b, nir_ieq_imm(b, nir_load_var(b, vars->idx), 1));