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/*
* Copyright © 2016 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.
*/
#ifndef NIR_LOOP_ANALYZE_H
#define NIR_LOOP_ANALYZE_H
#include "nir.h"
/* Returns true if nir_cf_node contains a jump other than the expected_jump
* parameter.
*/
static inline bool
contains_other_jump(nir_cf_node *node, nir_instr *expected_jump)
{
switch (node->type) {
case nir_cf_node_block: {
nir_instr *lst_instr = nir_block_last_instr(nir_cf_node_as_block(node));
/* dead_cf should have eliminated any instruction after the first break
*/
nir_foreach_instr(instr, nir_cf_node_as_block(node))
assert(instr->type != nir_instr_type_jump || instr == lst_instr);
if (lst_instr && lst_instr->type == nir_instr_type_jump &&
lst_instr != expected_jump)
return true;
else
return false;
}
case nir_cf_node_if: {
nir_if *if_stmt = nir_cf_node_as_if(node);
foreach_list_typed_safe(nir_cf_node, node, node, &if_stmt->then_list) {
if (contains_other_jump(node, expected_jump))
return true;
}
foreach_list_typed_safe(nir_cf_node, node, node, &if_stmt->else_list) {
if (contains_other_jump(node, expected_jump))
return true;
}
return false;
}
case nir_cf_node_loop:
return true;
default:
unreachable("Unhandled cf node type");
}
}
/* Here we define a trivial if as containing only a single break that must be
* located at the end of either the then or else branch of the top level if,
* there must be no other breaks or any other type of jump. Or we pass NULL
* to break_block the if must contains no jumps at all.
*/
static inline bool
nir_is_trivial_loop_if(nir_if *nif, nir_block *break_block)
{
nir_instr *last_instr = NULL;
if (break_block) {
last_instr = nir_block_last_instr(break_block);
assert(last_instr && last_instr->type == nir_instr_type_jump &&
nir_instr_as_jump(last_instr)->type == nir_jump_break);
}
if (contains_other_jump(&nif->cf_node, last_instr))
return false;
return true;
}
static inline bool
nir_block_ends_in_break(nir_block *block)
{
if (exec_list_is_empty(&block->instr_list))
return false;
nir_instr *instr = nir_block_last_instr(block);
return instr->type == nir_instr_type_jump &&
nir_instr_as_jump(instr)->type == nir_jump_break;
}
#endif /* NIR_LOOP_ANALYZE_H */
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