text: /*
   * Copyright © 2020 Intel Corporation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   */
  
  #include "anv_nir.h"
  #include "nir_builder.h"
  
  static bool
  lower_ubo_load_instr(nir_builder *b, nir_instr *instr, UNUSED void *_data)
  {
     if (instr->type != nir_instr_type_intrinsic)
        return false;
  
     nir_intrinsic_instr *load = nir_instr_as_intrinsic(instr);
     if (load->intrinsic != nir_intrinsic_load_global_constant_offset &&
         load->intrinsic != nir_intrinsic_load_global_constant_bounded)
        return false;
  
     b->cursor = nir_before_instr(instr);
  
     nir_ssa_def *base_addr = load->src[0].ssa;
     nir_ssa_def *bound = NULL;
     if (load->intrinsic == nir_intrinsic_load_global_constant_bounded)
        bound = load->src[2].ssa;
  
     unsigned bit_size = load->dest.ssa.bit_size;
     assert(bit_size >= 8 && bit_size % 8 == 0);
     unsigned byte_size = bit_size / 8;
  
     nir_ssa_def *val;
     if (nir_src_is_const(load->src[1])) {
        uint32_t offset = nir_src_as_uint(load->src[1]);
  
        /* Things should be component-aligned. */
        assert(offset % byte_size == 0);
  
        assert(ANV_UBO_ALIGNMENT == 64);
  
        unsigned suboffset = offset % 64;
        uint64_t aligned_offset = offset - suboffset;
  
        /* Load two just in case we go over a 64B boundary */
        nir_ssa_def *data[2];
        for (unsigned i = 0; i < 2; i++) {
           nir_ssa_def *pred;
           if (bound) {
              pred = nir_ilt(b, nir_imm_int(b, aligned_offset + i * 64 + 63),
                                bound);
           } else {
              pred = nir_imm_true(b);
           }
  
           nir_ssa_def *addr = nir_iadd_imm(b, base_addr,
                                            aligned_offset + i * 64);
  
           data[i] = nir_load_global_const_block_intel(b, 16, addr, pred);
        }
  
        val = nir_extract_bits(b, data, 2, suboffset * 8,
                               load->num_components, bit_size);
     } else {
        nir_ssa_def *offset = load->src[1].ssa;
        nir_ssa_def *addr = nir_iadd(b, base_addr, nir_u2u64(b, offset));
  
        if (bound) {
           nir_ssa_def *zero = nir_imm_zero(b, load->num_components, bit_size);
  
           unsigned load_size = byte_size * load->num_components;
           nir_ssa_def *in_bounds =
              nir_ilt(b, nir_iadd_imm(b, offset, load_size - 1), bound);
  
           nir_push_if(b, in_bounds);
  
           nir_ssa_def *load_val =
              nir_build_load_global_constant(b, load->dest.ssa.num_components,
                                             load->dest.ssa.bit_size, addr,
                                             .access = nir_intrinsic_access(load),
                                             .align_mul = nir_intrinsic_align_mul(load),
                                             .align_offset = nir_intrinsic_align_offset(load));
  
           nir_pop_if(b, NULL);
  
           val = nir_if_phi(b, load_val, zero);
        } else {
           val = nir_build_load_global_constant(b, load->dest.ssa.num_components,
                                                load->dest.ssa.bit_size, addr,
                                                .access = nir_intrinsic_access(load),
                                                .align_mul = nir_intrinsic_align_mul(load),
                                                .align_offset = nir_intrinsic_align_offset(load));
        }
     }
  
     nir_ssa_def_rewrite_uses(&load->dest.ssa, val);
     nir_instr_remove(&load->instr);
  
     return true;
  }
  
  bool
  anv_nir_lower_ubo_loads(nir_shader *shader)
  {
     return nir_shader_instructions_pass(shader, lower_ubo_load_instr,
                                         nir_metadata_block_index |
                                         nir_metadata_dominance,
                                         NULL);
  }
  