2 * Copyright (c) 2016 Intel Corporation
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9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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25 #include "compiler/nir/nir_builder.h"
27 struct lower_intrinsics_state
{
29 unsigned dispatch_width
;
30 nir_function_impl
*impl
;
33 unsigned local_workgroup_size
;
37 lower_cs_intrinsics_convert_block(struct lower_intrinsics_state
*state
,
40 bool progress
= false;
41 nir_builder
*b
= &state
->builder
;
42 nir_shader
*nir
= state
->nir
;
44 /* Reuse calculated values inside the block. */
45 nir_ssa_def
*local_index
= NULL
;
46 nir_ssa_def
*local_id
= NULL
;
48 nir_foreach_instr_safe(instr
, block
) {
49 if (instr
->type
!= nir_instr_type_intrinsic
)
52 nir_intrinsic_instr
*intrinsic
= nir_instr_as_intrinsic(instr
);
54 b
->cursor
= nir_after_instr(&intrinsic
->instr
);
57 switch (intrinsic
->intrinsic
) {
58 case nir_intrinsic_load_local_invocation_index
:
59 case nir_intrinsic_load_local_invocation_id
: {
60 /* First time we are using those, so let's calculate them. */
64 nir_ssa_def
*subgroup_id
;
65 if (state
->local_workgroup_size
<= state
->dispatch_width
)
66 subgroup_id
= nir_imm_int(b
, 0);
68 subgroup_id
= nir_load_subgroup_id(b
);
70 nir_ssa_def
*thread_local_id
=
71 nir_imul_imm(b
, subgroup_id
, state
->dispatch_width
);
72 nir_ssa_def
*channel
= nir_load_subgroup_invocation(b
);
73 nir_ssa_def
*linear
= nir_iadd(b
, channel
, thread_local_id
);
75 nir_ssa_def
*size_x
= nir_imm_int(b
, nir
->info
.cs
.local_size
[0]);
76 nir_ssa_def
*size_y
= nir_imm_int(b
, nir
->info
.cs
.local_size
[1]);
78 /* The local invocation index and ID must respect the following
80 * gl_LocalInvocationID.x =
81 * gl_LocalInvocationIndex % gl_WorkGroupSize.x;
82 * gl_LocalInvocationID.y =
83 * (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
85 * gl_LocalInvocationID.z =
86 * (gl_LocalInvocationIndex /
87 * (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
90 * However, the final % gl_WorkGroupSize.z does nothing unless we
91 * accidentally end up with a gl_LocalInvocationIndex that is too
92 * large so it can safely be omitted.
95 if (state
->nir
->info
.cs
.derivative_group
!= DERIVATIVE_GROUP_QUADS
) {
96 /* If we are not grouping in quads, just set the local invocatio
97 * index linearly, and calculate local invocation ID from that.
101 nir_ssa_def
*id_x
, *id_y
, *id_z
;
102 id_x
= nir_umod(b
, local_index
, size_x
);
103 id_y
= nir_umod(b
, nir_udiv(b
, local_index
, size_x
), size_y
);
104 id_z
= nir_udiv(b
, local_index
, nir_imul(b
, size_x
, size_y
));
105 local_id
= nir_vec3(b
, id_x
, id_y
, id_z
);
107 /* For quads, first we figure out the 2x2 grid the invocation
108 * belongs to -- treating extra Z layers as just more rows.
109 * Then map that into local invocation ID (trivial) and local
110 * invocation index. Skipping Z simplify index calculation.
113 nir_ssa_def
*one
= nir_imm_int(b
, 1);
114 nir_ssa_def
*double_size_x
= nir_ishl(b
, size_x
, one
);
116 /* ID within a pair of rows, where each group of 4 is 2x2 quad. */
117 nir_ssa_def
*row_pair_id
= nir_umod(b
, linear
, double_size_x
);
118 nir_ssa_def
*y_row_pairs
= nir_udiv(b
, linear
, double_size_x
);
122 nir_iand(b
, row_pair_id
, one
),
123 nir_iand(b
, nir_ishr(b
, row_pair_id
, one
),
124 nir_imm_int(b
, 0xfffffffe)));
127 nir_ishl(b
, y_row_pairs
, one
),
128 nir_iand(b
, nir_ishr(b
, row_pair_id
, one
), one
));
130 local_id
= nir_vec3(b
, x
,
131 nir_umod(b
, y
, size_y
),
132 nir_udiv(b
, y
, size_y
));
133 local_index
= nir_iadd(b
, x
, nir_imul(b
, y
, size_x
));
139 if (intrinsic
->intrinsic
== nir_intrinsic_load_local_invocation_id
)
142 sysval
= local_index
;
146 case nir_intrinsic_load_subgroup_id
:
147 if (state
->local_workgroup_size
> 8)
150 /* For small workgroup sizes, we know subgroup_id will be zero */
151 sysval
= nir_imm_int(b
, 0);
154 case nir_intrinsic_load_num_subgroups
: {
155 unsigned local_workgroup_size
=
156 nir
->info
.cs
.local_size
[0] * nir
->info
.cs
.local_size
[1] *
157 nir
->info
.cs
.local_size
[2];
158 unsigned num_subgroups
=
159 DIV_ROUND_UP(local_workgroup_size
, state
->dispatch_width
);
160 sysval
= nir_imm_int(b
, num_subgroups
);
168 nir_ssa_def_rewrite_uses(&intrinsic
->dest
.ssa
, nir_src_for_ssa(sysval
));
169 nir_instr_remove(&intrinsic
->instr
);
171 state
->progress
= true;
178 lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state
*state
)
180 nir_builder_init(&state
->builder
, state
->impl
);
182 nir_foreach_block(block
, state
->impl
) {
183 lower_cs_intrinsics_convert_block(state
, block
);
186 nir_metadata_preserve(state
->impl
,
187 nir_metadata_block_index
| nir_metadata_dominance
);
191 brw_nir_lower_cs_intrinsics(nir_shader
*nir
,
192 unsigned dispatch_width
)
194 assert(nir
->info
.stage
== MESA_SHADER_COMPUTE
);
196 struct lower_intrinsics_state state
= {
198 .dispatch_width
= dispatch_width
,
201 assert(!nir
->info
.cs
.local_size_variable
);
202 state
.local_workgroup_size
= nir
->info
.cs
.local_size
[0] *
203 nir
->info
.cs
.local_size
[1] *
204 nir
->info
.cs
.local_size
[2];
206 /* Constraints from NV_compute_shader_derivatives. */
207 if (nir
->info
.cs
.derivative_group
== DERIVATIVE_GROUP_QUADS
) {
208 assert(nir
->info
.cs
.local_size
[0] % 2 == 0);
209 assert(nir
->info
.cs
.local_size
[1] % 2 == 0);
210 } else if (nir
->info
.cs
.derivative_group
== DERIVATIVE_GROUP_LINEAR
) {
211 assert(state
.local_workgroup_size
% 4 == 0);
214 nir_foreach_function(function
, nir
) {
215 if (function
->impl
) {
216 state
.impl
= function
->impl
;
217 lower_cs_intrinsics_convert_impl(&state
);
221 return state
.progress
;