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/*
* Copyright © 2015 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 "nir.h"
#include "nir_builder.h"
static nir_intrinsic_instr *
as_intrinsic(nir_instr *instr, nir_intrinsic_op op)
{
if (instr->type != nir_instr_type_intrinsic)
return NULL;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
if (intrin->intrinsic != op)
return NULL;
return intrin;
}
static nir_intrinsic_instr *
as_set_vertex_count(nir_instr *instr)
{
return as_intrinsic(instr, nir_intrinsic_set_vertex_count);
}
/**
* If a geometry shader emits a constant number of vertices, return the
* number of vertices. Otherwise, return -1 (unknown).
*
* This only works if you've used nir_lower_gs_intrinsics() to do vertex
* counting at the NIR level.
*/
int
nir_gs_count_vertices(const nir_shader *shader)
{
int count = -1;
nir_foreach_function(shader, function) {
if (!function->impl)
continue;
/* set_vertex_count intrinsics only appear in predecessors of the
* end block. So we don't need to walk all of them.
*/
struct set_entry *entry;
set_foreach(function->impl->end_block->predecessors, entry) {
nir_block *block = (nir_block *) entry->key;
nir_foreach_instr_reverse(block, instr) {
nir_intrinsic_instr *intrin = as_set_vertex_count(instr);
if (!intrin)
continue;
nir_const_value *val = nir_src_as_const_value(intrin->src[0]);
/* We've found a non-constant value. Bail. */
if (!val)
return -1;
if (count == -1)
count = val->i32[0];
/* We've found contradictory set_vertex_count intrinsics.
* This can happen if there are early-returns in main() and
* different paths emit different numbers of vertices.
*/
if (count != val->i32[0])
return -1;
}
}
}
return count;
}
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