mesa/src/intel/compiler/brw_nir_lower_shading_rate_...

115 lines
4.4 KiB
C

/*
* Copyright (c) 2021 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.
*/
/*
* Lower the shading rate output from the bit field format described in the
* SPIRV spec :
*
* bit | name | description
* 0 | Vertical2Pixels | Fragment invocation covers 2 pixels vertically
* 1 | Vertical4Pixels | Fragment invocation covers 4 pixels vertically
* 2 | Horizontal2Pixels | Fragment invocation covers 2 pixels horizontally
* 3 | Horizontal4Pixels | Fragment invocation covers 4 pixels horizontally
*
* into a single dword composed of 2 fp16 to be stored in the dword 0 of the
* VUE header.
*
* When no horizontal/vertical bits are set, the size in pixel size in that
* dimension is assumed to be 1.
*
* According to the specification, the shading rate output can be read &
* written. A read after a write should report a different value if the
* implementation decides on different primitive shading rate for some reason.
* This is never the case in our implementation.
*/
#include "brw_nir.h"
#include "compiler/nir/nir_builder.h"
static bool
lower_shading_rate_output_instr(nir_builder *b, nir_instr *instr,
UNUSED void *_state)
{
if (instr->type != nir_instr_type_intrinsic)
return false;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
nir_intrinsic_op op = intrin->intrinsic;
if (op != nir_intrinsic_load_output &&
op != nir_intrinsic_store_output &&
op != nir_intrinsic_load_per_primitive_output &&
op != nir_intrinsic_store_per_primitive_output)
return false;
struct nir_io_semantics io = nir_intrinsic_io_semantics(intrin);
if (io.location != VARYING_SLOT_PRIMITIVE_SHADING_RATE)
return false;
bool is_store = op == nir_intrinsic_store_output ||
op == nir_intrinsic_store_per_primitive_output;
b->cursor = is_store ? nir_before_instr(instr) : nir_after_instr(instr);
if (is_store) {
assert(intrin->src[0].is_ssa);
nir_ssa_def *bit_field = intrin->src[0].ssa;
nir_ssa_def *fp16_x =
nir_i2f16(b,
nir_ishl(b, nir_imm_int(b, 1),
nir_ishr_imm(b, bit_field, 2)));
nir_ssa_def *fp16_y =
nir_i2f16(b,
nir_ishl(b, nir_imm_int(b, 1),
nir_iand_imm(b, bit_field, 0x3)));
nir_ssa_def *packed_fp16_xy = nir_pack_32_2x16_split(b, fp16_x, fp16_y);
nir_instr_rewrite_src(instr, &intrin->src[0],
nir_src_for_ssa(packed_fp16_xy));
} else {
nir_ssa_def *packed_fp16_xy = &intrin->dest.ssa;
nir_ssa_def *u32_x =
nir_i2i32(b, nir_unpack_32_2x16_split_x(b, packed_fp16_xy));
nir_ssa_def *u32_y =
nir_i2i32(b, nir_unpack_32_2x16_split_y(b, packed_fp16_xy));
nir_ssa_def *bit_field =
nir_ior(b, nir_ishl_imm(b, nir_ushr_imm(b, u32_x, 1), 2),
nir_ushr_imm(b, u32_y, 1));
nir_ssa_def_rewrite_uses_after(packed_fp16_xy, bit_field,
bit_field->parent_instr);
}
return true;
}
bool
brw_nir_lower_shading_rate_output(nir_shader *nir)
{
return nir_shader_instructions_pass(nir, lower_shading_rate_output_instr,
nir_metadata_block_index |
nir_metadata_dominance, NULL);
}