intel/compiler: Get mesh_global_addr from the Inline Parameter for Task/Mesh

Signed-off-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13661>

src/compiler/nir/nir_intrinsics.py

@@ -1320,6 +1320,9 @@ store("ssbo_block_intel", [-1, 1], [WRITE_MASK, ACCESS, ALIGN_MUL, ALIGN_OFFSET]
 # src[] = { value, offset }.
 store("shared_block_intel", [1], [BASE, WRITE_MASK, ALIGN_MUL, ALIGN_OFFSET])
 
+# Intrinsics for Intel mesh shading
+system_value("mesh_global_arg_addr_intel", 1, bit_sizes=[64])
+
 # Intrinsics for Intel bindless thread dispatch
 system_value("btd_dss_id_intel", 1)
 system_value("btd_stack_id_intel", 1)

src/compiler/nir/nir_lower_shader_calls.c

@@ -176,6 +176,7 @@ can_remat_instr(nir_instr *instr, struct brw_bitset *remat)
       case nir_intrinsic_load_ray_miss_sbt_stride_intel:
       case nir_intrinsic_load_callable_sbt_addr_intel:
       case nir_intrinsic_load_callable_sbt_stride_intel:
+      case nir_intrinsic_load_mesh_global_arg_addr_intel:
          /* Notably missing from the above list is btd_local_arg_addr_intel.
           * This is because the resume shader will have a different local
           * argument pointer because it has a different BSR.  Any access of

src/intel/compiler/brw_mesh.cpp

@@ -30,6 +30,37 @@
 
 using namespace brw;
 
+static bool
+brw_nir_lower_load_uniforms_filter(const nir_instr *instr,
+                                   UNUSED const void *data)
+{
+   if (instr->type != nir_instr_type_intrinsic)
+      return false;
+   nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+   return intrin->intrinsic == nir_intrinsic_load_uniform;
+}
+
+static nir_ssa_def *
+brw_nir_lower_load_uniforms_impl(nir_builder *b, nir_instr *instr,
+                                 UNUSED void *data)
+{
+   assert(instr->type == nir_instr_type_intrinsic);
+   nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+   assert(intrin->intrinsic == nir_intrinsic_load_uniform);
+
+   return brw_nir_load_global_const(b,
+                                    intrin,
+                                    nir_load_mesh_global_arg_addr_intel(b),
+                                    0);
+}
+
+static void
+brw_nir_lower_load_uniforms(nir_shader *nir)
+{
+   nir_shader_lower_instructions(nir, brw_nir_lower_load_uniforms_filter,
+                                 brw_nir_lower_load_uniforms_impl, NULL);
+}
+
 static inline int
 type_size_scalar_dwords(const struct glsl_type *type, bool bindless)
 {
@@ -150,6 +181,7 @@ brw_compile_task(const struct brw_compiler *compiler,
       brw_nir_apply_key(shader, compiler, &key->base, dispatch_width, true /* is_scalar */);
 
       NIR_PASS_V(shader, brw_nir_lower_tue_outputs, &prog_data->map);
+      NIR_PASS_V(shader, brw_nir_lower_load_uniforms);
       NIR_PASS_V(shader, brw_nir_lower_simd, dispatch_width);
 
       brw_postprocess_nir(shader, compiler, true /* is_scalar */, debug_enabled,
@@ -522,6 +554,11 @@ brw_compile_mesh(const struct brw_compiler *compiler,
       NIR_PASS_V(shader, brw_nir_lower_tue_inputs, params->tue_map);
       NIR_PASS_V(shader, brw_nir_lower_mue_outputs, &prog_data->map);
       NIR_PASS_V(shader, brw_nir_adjust_offset_for_arrayed_indices, &prog_data->map);
+
+      /* Load uniforms can do a better job for constants, so fold before it. */
+      NIR_PASS_V(shader, nir_opt_constant_folding);
+      NIR_PASS_V(shader, brw_nir_lower_load_uniforms);
+
       NIR_PASS_V(shader, brw_nir_lower_simd, dispatch_width);
 
       brw_postprocess_nir(shader, compiler, true /* is_scalar */, debug_enabled,
@@ -937,6 +974,12 @@ fs_visitor::nir_emit_task_mesh_intrinsic(const fs_builder &bld,
       dest = get_nir_dest(instr->dest);
 
    switch (instr->intrinsic) {
+   case nir_intrinsic_load_mesh_global_arg_addr_intel:
+      assert(payload.num_regs == 3 || payload.num_regs == 4);
+      /* Passed in the Inline Parameter, the last element of the payload. */
+      bld.MOV(dest, retype(brw_vec1_grf(payload.num_regs - 1, 0), dest.type));
+      break;
+
    case nir_intrinsic_load_local_invocation_index:
    case nir_intrinsic_load_local_invocation_id:
       /* Local_ID.X is given by the HW in the shader payload. */