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intel/fs: move lower of non-uniform at_sample barycentric to NIR

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We use a non-uniform lowering loop in the backend which we can do
better in NIR because we can also use divergence analysis there.

This change also limits VGRF usage to a single VGRF to hold the sample
ID in the backend.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24716>
This commit is contained in:
Lionel Landwerlin
2023-08-24 01:23:00 +03:00
committed by Marge Bot
parent 68027bd38e
commit 74a40cc4b6
5 changed files with 97 additions and 55 deletions
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src/intel/compiler/brw_fs_nir.cpp
+12 -55
View File
@@ -3536,66 +3536,23 @@ fs_visitor::nir_emit_fs_intrinsic(const fs_builder &bld,
const glsl_interp_mode interpolation =
(enum glsl_interp_mode) nir_intrinsic_interp_mode(instr);
fs_reg msg_data;
if (nir_src_is_const(instr->src[0])) {
unsigned msg_data = nir_src_as_uint(instr->src[0]) << 4;
emit_pixel_interpolater_send(bld,
FS_OPCODE_INTERPOLATE_AT_SAMPLE,
dest,
fs_reg(), /* src */
brw_imm_ud(msg_data),
interpolation);
msg_data = brw_imm_ud(nir_src_as_uint(instr->src[0]) << 4);
} else {
const fs_reg sample_src = retype(get_nir_src(instr->src[0]),
BRW_REGISTER_TYPE_UD);
if (nir_src_is_always_uniform(instr->src[0])) {
const fs_reg sample_id = bld.emit_uniformize(sample_src);
const fs_reg msg_data = vgrf(glsl_type::uint_type);
bld.exec_all().group(1, 0)
.SHL(msg_data, sample_id, brw_imm_ud(4u));
emit_pixel_interpolater_send(bld,
FS_OPCODE_INTERPOLATE_AT_SAMPLE,
dest,
fs_reg(), /* src */
component(msg_data, 0),
interpolation);
} else {
/* Make a loop that sends a message to the pixel interpolater
* for the sample number in each live channel. If there are
* multiple channels with the same sample number then these
* will be handled simultaneously with a single iteration of
* the loop.
*/
bld.emit(BRW_OPCODE_DO);
/* Get the next live sample number into sample_id_reg */
const fs_reg sample_id = bld.emit_uniformize(sample_src);
/* Set the flag register so that we can perform the send
* message on all channels that have the same sample number
*/
bld.CMP(bld.null_reg_ud(),
sample_src, sample_id,
BRW_CONDITIONAL_EQ);
const fs_reg msg_data = vgrf(glsl_type::uint_type);
bld.exec_all().group(1, 0)
.SHL(msg_data, sample_id, brw_imm_ud(4u));
fs_inst *inst =
emit_pixel_interpolater_send(bld,
FS_OPCODE_INTERPOLATE_AT_SAMPLE,
dest,
fs_reg(), /* src */
component(msg_data, 0),
interpolation);
set_predicate(BRW_PREDICATE_NORMAL, inst);
/* Continue the loop if there are any live channels left */
set_predicate_inv(BRW_PREDICATE_NORMAL,
true, /* inverse */
bld.emit(BRW_OPCODE_WHILE));
}
const fs_reg sample_id = bld.emit_uniformize(sample_src);
msg_data = component(bld.group(8, 0).vgrf(BRW_REGISTER_TYPE_UD), 0);
bld.exec_all().group(1, 0).SHL(msg_data, sample_id, brw_imm_ud(4u));
}
emit_pixel_interpolater_send(bld,
FS_OPCODE_INTERPOLATE_AT_SAMPLE,
dest,
fs_reg(), /* src */
msg_data,
interpolation);
break;
}