2 * Copyright © 2020 Valve Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
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,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
28 * This pass is intended as workaround for game bugs to force correct
29 * derivatives after kill. This lowering is not valid in the general case
30 * as it might change the result of subgroup operations and loop behavior.
32 * discard() will be lowered as demote() and gl_HelperInvocation
33 * will be lowered as helperInvocationEXT().
36 nir_lower_discard_to_demote(nir_shader
*shader
)
38 if (shader
->info
.stage
!= MESA_SHADER_FRAGMENT
)
41 bool progress
= false;
43 nir_foreach_function(function
, shader
) {
44 nir_foreach_block(block
, function
->impl
) {
45 nir_foreach_instr(instr
, block
) {
46 if (instr
->type
!= nir_instr_type_intrinsic
)
49 nir_intrinsic_instr
*intrin
= nir_instr_as_intrinsic(instr
);
50 switch (intrin
->intrinsic
) {
51 case nir_intrinsic_discard
:
52 intrin
->intrinsic
= nir_intrinsic_demote
;
53 shader
->info
.fs
.uses_demote
= true;
55 case nir_intrinsic_discard_if
:
56 intrin
->intrinsic
= nir_intrinsic_demote_if
;
57 shader
->info
.fs
.uses_demote
= true;
59 case nir_intrinsic_load_helper_invocation
:
60 intrin
->intrinsic
= nir_intrinsic_is_helper_invocation
;