2015-07-22 03:54:18 +01:00
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/*
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* Copyright © 2014 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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* Authors:
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* Connor Abbott (cwabbott0@gmail.com)
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*
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*/
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#include "nir_control_flow_private.h"
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/**
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* \name Control flow modification
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*
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* These functions modify the control flow tree while keeping the control flow
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* graph up-to-date. The invariants respected are:
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* 1. Each then statement, else statement, or loop body must have at least one
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* control flow node.
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* 2. Each if-statement and loop must have one basic block before it and one
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* after.
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* 3. Two basic blocks cannot be directly next to each other.
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* 4. If a basic block has a jump instruction, there must be only one and it
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* must be at the end of the block.
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*
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* The purpose of the second one is so that we have places to insert code during
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* GCM, as well as eliminating the possibility of critical edges.
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*/
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/*@{*/
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static inline void
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block_add_pred(nir_block *block, nir_block *pred)
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{
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_mesa_set_add(block->predecessors, pred);
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}
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2015-09-03 08:31:19 +01:00
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static inline void
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block_remove_pred(nir_block *block, nir_block *pred)
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{
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struct set_entry *entry = _mesa_set_search(block->predecessors, pred);
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assert(entry);
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_mesa_set_remove(block->predecessors, entry);
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}
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2015-07-22 03:54:18 +01:00
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static void
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link_blocks(nir_block *pred, nir_block *succ1, nir_block *succ2)
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{
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pred->successors[0] = succ1;
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2015-07-22 03:54:29 +01:00
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if (succ1 != NULL)
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block_add_pred(succ1, pred);
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2015-07-22 03:54:18 +01:00
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pred->successors[1] = succ2;
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if (succ2 != NULL)
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block_add_pred(succ2, pred);
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}
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static void
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unlink_blocks(nir_block *pred, nir_block *succ)
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{
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if (pred->successors[0] == succ) {
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pred->successors[0] = pred->successors[1];
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pred->successors[1] = NULL;
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} else {
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assert(pred->successors[1] == succ);
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pred->successors[1] = NULL;
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}
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2015-09-03 08:31:19 +01:00
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block_remove_pred(succ, pred);
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2015-07-22 03:54:18 +01:00
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}
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static void
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unlink_block_successors(nir_block *block)
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{
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if (block->successors[1] != NULL)
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unlink_blocks(block, block->successors[1]);
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2015-09-02 06:56:29 +01:00
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if (block->successors[0] != NULL)
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unlink_blocks(block, block->successors[0]);
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2015-07-22 03:54:18 +01:00
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}
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static void
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link_non_block_to_block(nir_cf_node *node, nir_block *block)
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{
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if (node->type == nir_cf_node_if) {
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/*
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* We're trying to link an if to a block after it; this just means linking
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* the last block of the then and else branches.
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*/
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nir_if *if_stmt = nir_cf_node_as_if(node);
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2016-10-06 03:08:57 +01:00
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nir_block *last_then_block = nir_if_last_then_block(if_stmt);
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nir_block *last_else_block = nir_if_last_else_block(if_stmt);
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2015-07-22 03:54:18 +01:00
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2018-08-24 15:34:05 +01:00
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if (!nir_block_ends_in_jump(last_then_block)) {
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2015-07-22 03:54:18 +01:00
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unlink_block_successors(last_then_block);
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link_blocks(last_then_block, block, NULL);
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}
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2018-08-24 15:34:05 +01:00
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if (!nir_block_ends_in_jump(last_else_block)) {
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2015-07-22 03:54:18 +01:00
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unlink_block_successors(last_else_block);
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link_blocks(last_else_block, block, NULL);
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}
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} else {
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assert(node->type == nir_cf_node_loop);
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}
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}
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static void
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link_block_to_non_block(nir_block *block, nir_cf_node *node)
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{
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if (node->type == nir_cf_node_if) {
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/*
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* We're trying to link a block to an if after it; this just means linking
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* the block to the first block of the then and else branches.
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*/
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nir_if *if_stmt = nir_cf_node_as_if(node);
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2016-10-06 03:08:57 +01:00
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nir_block *first_then_block = nir_if_first_then_block(if_stmt);
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nir_block *first_else_block = nir_if_first_else_block(if_stmt);
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2015-07-22 03:54:18 +01:00
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unlink_block_successors(block);
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link_blocks(block, first_then_block, first_else_block);
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} else {
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/*
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* For similar reasons as the corresponding case in
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* link_non_block_to_block(), don't worry about if the loop header has
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* any predecessors that need to be unlinked.
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*/
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nir_loop *loop = nir_cf_node_as_loop(node);
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2016-10-06 03:08:57 +01:00
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nir_block *loop_header_block = nir_loop_first_block(loop);
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2015-07-22 03:54:18 +01:00
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unlink_block_successors(block);
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link_blocks(block, loop_header_block, NULL);
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}
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}
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nir/cf: Don't break outer-block successors in split_block_beginning().
Consider the following NIR:
block block_0;
/* succs: block_1 block_2 */
if (...) {
block block_1;
...
} else {
block block_2;
}
Calling split_block_beginning() on block_1 would break block_0's
successors: link_block() sets both successors of a block, so calling
link_block(block_0, new_block, NULL) would throw away the second
successor, leaving only /* succ: new_block */. This is invalid: the
block before an if statement must have two successors.
Changing the call to link_block(pred, new_block, pred->successors[0])
would correctly leave both successors in place, but because unlink_block
may shift successor[1] to successor[0], it may not preserve the original
order. NIR maintains a convention that successor[0] must point to the
"then" block, while successor[1] points to the "else" block, so we need
to take care to preserve this ordering.
This patch creates a new function that swaps out one successor for
another, preserving the ordering. It then uses this to fix the issue.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
2015-09-03 08:33:50 +01:00
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/**
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* Replace a block's successor with a different one.
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*/
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static void
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replace_successor(nir_block *block, nir_block *old_succ, nir_block *new_succ)
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{
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if (block->successors[0] == old_succ) {
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block->successors[0] = new_succ;
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} else {
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assert(block->successors[1] == old_succ);
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block->successors[1] = new_succ;
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}
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block_remove_pred(old_succ, block);
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block_add_pred(new_succ, block);
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}
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2015-07-22 03:54:18 +01:00
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/**
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* Takes a basic block and inserts a new empty basic block before it, making its
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* predecessors point to the new block. This essentially splits the block into
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* an empty header and a body so that another non-block CF node can be inserted
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* between the two. Note that this does *not* link the two basic blocks, so
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* some kind of cleanup *must* be performed after this call.
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*/
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static nir_block *
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split_block_beginning(nir_block *block)
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{
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nir_block *new_block = nir_block_create(ralloc_parent(block));
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new_block->cf_node.parent = block->cf_node.parent;
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exec_node_insert_node_before(&block->cf_node.node, &new_block->cf_node.node);
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set_foreach(block->predecessors, entry) {
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nir_block *pred = (nir_block *) entry->key;
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nir/cf: Don't break outer-block successors in split_block_beginning().
Consider the following NIR:
block block_0;
/* succs: block_1 block_2 */
if (...) {
block block_1;
...
} else {
block block_2;
}
Calling split_block_beginning() on block_1 would break block_0's
successors: link_block() sets both successors of a block, so calling
link_block(block_0, new_block, NULL) would throw away the second
successor, leaving only /* succ: new_block */. This is invalid: the
block before an if statement must have two successors.
Changing the call to link_block(pred, new_block, pred->successors[0])
would correctly leave both successors in place, but because unlink_block
may shift successor[1] to successor[0], it may not preserve the original
order. NIR maintains a convention that successor[0] must point to the
"then" block, while successor[1] points to the "else" block, so we need
to take care to preserve this ordering.
This patch creates a new function that swaps out one successor for
another, preserving the ordering. It then uses this to fix the issue.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
2015-09-03 08:33:50 +01:00
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replace_successor(pred, block, new_block);
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2015-07-22 03:54:18 +01:00
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}
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2015-07-22 03:54:23 +01:00
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/* Any phi nodes must stay part of the new block, or else their
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2019-01-26 09:05:14 +00:00
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* sources will be messed up.
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2015-07-22 03:54:23 +01:00
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*/
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2016-04-27 02:34:19 +01:00
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nir_foreach_instr_safe(instr, block) {
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2015-07-22 03:54:23 +01:00
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if (instr->type != nir_instr_type_phi)
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break;
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exec_node_remove(&instr->node);
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instr->block = new_block;
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2019-01-26 09:05:14 +00:00
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exec_list_push_tail(&new_block->instr_list, &instr->node);
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2015-07-22 03:54:23 +01:00
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}
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2015-07-22 03:54:18 +01:00
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return new_block;
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}
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static void
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rewrite_phi_preds(nir_block *block, nir_block *old_pred, nir_block *new_pred)
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{
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2016-04-27 02:34:19 +01:00
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nir_foreach_instr_safe(instr, block) {
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2015-07-22 03:54:18 +01:00
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if (instr->type != nir_instr_type_phi)
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break;
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nir_phi_instr *phi = nir_instr_as_phi(instr);
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2016-04-27 04:16:21 +01:00
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nir_foreach_phi_src(src, phi) {
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2015-07-22 03:54:18 +01:00
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if (src->pred == old_pred) {
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src->pred = new_pred;
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break;
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}
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}
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}
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}
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2015-07-22 03:54:19 +01:00
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static void
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insert_phi_undef(nir_block *block, nir_block *pred)
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{
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nir_function_impl *impl = nir_cf_node_get_function(&block->cf_node);
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2016-04-27 02:34:19 +01:00
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nir_foreach_instr(instr, block) {
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2015-07-22 03:54:19 +01:00
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if (instr->type != nir_instr_type_phi)
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break;
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nir_phi_instr *phi = nir_instr_as_phi(instr);
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nir_ssa_undef_instr *undef =
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nir_ssa_undef_instr_create(ralloc_parent(phi),
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2016-03-23 07:04:09 +00:00
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phi->dest.ssa.num_components,
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phi->dest.ssa.bit_size);
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2015-07-22 03:54:19 +01:00
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nir_instr_insert_before_cf_list(&impl->body, &undef->instr);
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nir_phi_src *src = ralloc(phi, nir_phi_src);
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src->pred = pred;
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src->src.parent_instr = &phi->instr;
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src->src.is_ssa = true;
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src->src.ssa = &undef->def;
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list_addtail(&src->src.use_link, &undef->def.uses);
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exec_list_push_tail(&phi->srcs, &src->node);
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}
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}
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2015-07-22 03:54:18 +01:00
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/**
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* Moves the successors of source to the successors of dest, leaving both
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* successors of source NULL.
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*/
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static void
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move_successors(nir_block *source, nir_block *dest)
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{
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nir_block *succ1 = source->successors[0];
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nir_block *succ2 = source->successors[1];
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if (succ1) {
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unlink_blocks(source, succ1);
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rewrite_phi_preds(succ1, source, dest);
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}
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if (succ2) {
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unlink_blocks(source, succ2);
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rewrite_phi_preds(succ2, source, dest);
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}
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unlink_block_successors(dest);
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link_blocks(dest, succ1, succ2);
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}
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2015-07-22 03:54:22 +01:00
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/* Given a basic block with no successors that has been inserted into the
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* control flow tree, gives it the successors it would normally have assuming
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* it doesn't end in a jump instruction. Also inserts phi sources with undefs
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* if necessary.
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*/
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static void
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block_add_normal_succs(nir_block *block)
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{
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if (exec_node_is_tail_sentinel(block->cf_node.node.next)) {
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nir_cf_node *parent = block->cf_node.parent;
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if (parent->type == nir_cf_node_if) {
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nir_cf_node *next = nir_cf_node_next(parent);
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nir_block *next_block = nir_cf_node_as_block(next);
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link_blocks(block, next_block, NULL);
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2015-12-18 19:27:00 +00:00
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} else if (parent->type == nir_cf_node_loop) {
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2015-07-22 03:54:22 +01:00
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nir_loop *loop = nir_cf_node_as_loop(parent);
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2016-10-06 03:08:57 +01:00
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nir_block *head_block = nir_loop_first_block(loop);
|
2015-07-22 03:54:22 +01:00
|
|
|
|
|
|
|
link_blocks(block, head_block, NULL);
|
|
|
|
insert_phi_undef(head_block, block);
|
2015-12-18 19:27:00 +00:00
|
|
|
} else {
|
|
|
|
nir_function_impl *impl = nir_cf_node_as_function(parent);
|
|
|
|
link_blocks(block, impl->end_block, NULL);
|
2015-07-22 03:54:22 +01:00
|
|
|
}
|
|
|
|
} else {
|
|
|
|
nir_cf_node *next = nir_cf_node_next(&block->cf_node);
|
|
|
|
if (next->type == nir_cf_node_if) {
|
|
|
|
nir_if *next_if = nir_cf_node_as_if(next);
|
|
|
|
|
2016-10-06 03:08:57 +01:00
|
|
|
nir_block *first_then_block = nir_if_first_then_block(next_if);
|
|
|
|
nir_block *first_else_block = nir_if_first_else_block(next_if);
|
2015-07-22 03:54:22 +01:00
|
|
|
|
|
|
|
link_blocks(block, first_then_block, first_else_block);
|
|
|
|
} else {
|
|
|
|
nir_loop *next_loop = nir_cf_node_as_loop(next);
|
|
|
|
|
2016-10-06 03:08:57 +01:00
|
|
|
nir_block *first_block = nir_loop_first_block(next_loop);
|
2015-07-22 03:54:22 +01:00
|
|
|
|
|
|
|
link_blocks(block, first_block, NULL);
|
|
|
|
insert_phi_undef(first_block, block);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:18 +01:00
|
|
|
static nir_block *
|
|
|
|
split_block_end(nir_block *block)
|
|
|
|
{
|
|
|
|
nir_block *new_block = nir_block_create(ralloc_parent(block));
|
|
|
|
new_block->cf_node.parent = block->cf_node.parent;
|
|
|
|
exec_node_insert_after(&block->cf_node.node, &new_block->cf_node.node);
|
|
|
|
|
2018-08-24 15:34:05 +01:00
|
|
|
if (nir_block_ends_in_jump(block)) {
|
2015-07-22 03:54:25 +01:00
|
|
|
/* Figure out what successor block would've had if it didn't have a jump
|
|
|
|
* instruction, and make new_block have that successor.
|
|
|
|
*/
|
|
|
|
block_add_normal_succs(new_block);
|
|
|
|
} else {
|
|
|
|
move_successors(block, new_block);
|
|
|
|
}
|
2015-07-22 03:54:18 +01:00
|
|
|
|
|
|
|
return new_block;
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:31 +01:00
|
|
|
static nir_block *
|
|
|
|
split_block_before_instr(nir_instr *instr)
|
|
|
|
{
|
|
|
|
assert(instr->type != nir_instr_type_phi);
|
|
|
|
nir_block *new_block = split_block_beginning(instr->block);
|
|
|
|
|
2016-04-27 02:34:19 +01:00
|
|
|
nir_foreach_instr_safe(cur_instr, instr->block) {
|
2015-07-22 03:54:31 +01:00
|
|
|
if (cur_instr == instr)
|
|
|
|
break;
|
|
|
|
|
|
|
|
exec_node_remove(&cur_instr->node);
|
|
|
|
cur_instr->block = new_block;
|
|
|
|
exec_list_push_tail(&new_block->instr_list, &cur_instr->node);
|
|
|
|
}
|
|
|
|
|
|
|
|
return new_block;
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:32 +01:00
|
|
|
/* Splits a basic block at the point specified by the cursor. The "before" and
|
|
|
|
* "after" arguments are filled out with the blocks resulting from the split
|
|
|
|
* if non-NULL. Note that the "beginning" of the block is actually interpreted
|
|
|
|
* as before the first non-phi instruction, and it's illegal to split a block
|
|
|
|
* before a phi instruction.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void
|
|
|
|
split_block_cursor(nir_cursor cursor,
|
|
|
|
nir_block **_before, nir_block **_after)
|
|
|
|
{
|
|
|
|
nir_block *before, *after;
|
|
|
|
switch (cursor.option) {
|
|
|
|
case nir_cursor_before_block:
|
|
|
|
after = cursor.block;
|
|
|
|
before = split_block_beginning(cursor.block);
|
|
|
|
break;
|
|
|
|
|
|
|
|
case nir_cursor_after_block:
|
|
|
|
before = cursor.block;
|
|
|
|
after = split_block_end(cursor.block);
|
|
|
|
break;
|
|
|
|
|
|
|
|
case nir_cursor_before_instr:
|
|
|
|
after = cursor.instr->block;
|
|
|
|
before = split_block_before_instr(cursor.instr);
|
|
|
|
break;
|
|
|
|
|
|
|
|
case nir_cursor_after_instr:
|
|
|
|
/* We lower this to split_block_before_instr() so that we can keep the
|
|
|
|
* after-a-jump-instr case contained to split_block_end().
|
|
|
|
*/
|
|
|
|
if (nir_instr_is_last(cursor.instr)) {
|
|
|
|
before = cursor.instr->block;
|
|
|
|
after = split_block_end(cursor.instr->block);
|
|
|
|
} else {
|
|
|
|
after = cursor.instr->block;
|
|
|
|
before = split_block_before_instr(nir_instr_next(cursor.instr));
|
|
|
|
}
|
|
|
|
break;
|
2015-11-02 09:23:59 +00:00
|
|
|
|
|
|
|
default:
|
|
|
|
unreachable("not reached");
|
2015-07-22 03:54:32 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
if (_before)
|
|
|
|
*_before = before;
|
|
|
|
if (_after)
|
|
|
|
*_after = after;
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:18 +01:00
|
|
|
/**
|
|
|
|
* Inserts a non-basic block between two basic blocks and links them together.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void
|
|
|
|
insert_non_block(nir_block *before, nir_cf_node *node, nir_block *after)
|
|
|
|
{
|
|
|
|
node->parent = before->cf_node.parent;
|
|
|
|
exec_node_insert_after(&before->cf_node.node, &node->node);
|
|
|
|
link_block_to_non_block(before, node);
|
|
|
|
link_non_block_to_block(node, after);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* walk up the control flow tree to find the innermost enclosed loop */
|
|
|
|
static nir_loop *
|
|
|
|
nearest_loop(nir_cf_node *node)
|
|
|
|
{
|
|
|
|
while (node->type != nir_cf_node_loop) {
|
|
|
|
node = node->parent;
|
|
|
|
}
|
|
|
|
|
|
|
|
return nir_cf_node_as_loop(node);
|
|
|
|
}
|
|
|
|
|
2018-09-21 15:27:48 +01:00
|
|
|
static void
|
|
|
|
remove_phi_src(nir_block *block, nir_block *pred)
|
|
|
|
{
|
|
|
|
nir_foreach_instr(instr, block) {
|
|
|
|
if (instr->type != nir_instr_type_phi)
|
|
|
|
break;
|
|
|
|
|
|
|
|
nir_phi_instr *phi = nir_instr_as_phi(instr);
|
|
|
|
nir_foreach_phi_src_safe(src, phi) {
|
|
|
|
if (src->pred == pred) {
|
|
|
|
list_del(&src->src.use_link);
|
|
|
|
exec_node_remove(&src->node);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:18 +01:00
|
|
|
/*
|
|
|
|
* update the CFG after a jump instruction has been added to the end of a block
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
nir_handle_add_jump(nir_block *block)
|
|
|
|
{
|
|
|
|
nir_instr *instr = nir_block_last_instr(block);
|
|
|
|
nir_jump_instr *jump_instr = nir_instr_as_jump(instr);
|
|
|
|
|
2018-09-21 15:27:48 +01:00
|
|
|
if (block->successors[0])
|
|
|
|
remove_phi_src(block->successors[0], block);
|
|
|
|
if (block->successors[1])
|
|
|
|
remove_phi_src(block->successors[1], block);
|
2015-07-22 03:54:18 +01:00
|
|
|
unlink_block_successors(block);
|
|
|
|
|
|
|
|
nir_function_impl *impl = nir_cf_node_get_function(&block->cf_node);
|
|
|
|
nir_metadata_preserve(impl, nir_metadata_none);
|
|
|
|
|
2020-05-15 21:31:50 +01:00
|
|
|
switch (jump_instr->type) {
|
|
|
|
case nir_jump_return:
|
|
|
|
link_blocks(block, impl->end_block, NULL);
|
|
|
|
break;
|
|
|
|
|
|
|
|
case nir_jump_break: {
|
2015-07-22 03:54:18 +01:00
|
|
|
nir_loop *loop = nearest_loop(&block->cf_node);
|
2020-05-15 21:31:50 +01:00
|
|
|
nir_cf_node *after = nir_cf_node_next(&loop->cf_node);
|
|
|
|
nir_block *after_block = nir_cf_node_as_block(after);
|
|
|
|
link_blocks(block, after_block, NULL);
|
|
|
|
break;
|
|
|
|
}
|
2015-07-22 03:54:18 +01:00
|
|
|
|
2020-05-15 21:31:50 +01:00
|
|
|
case nir_jump_continue: {
|
|
|
|
nir_loop *loop = nearest_loop(&block->cf_node);
|
|
|
|
nir_block *first_block = nir_loop_first_block(loop);
|
|
|
|
link_blocks(block, first_block, NULL);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
default:
|
|
|
|
unreachable("Invalid jump type");
|
2015-07-22 03:54:18 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2016-08-31 22:45:08 +01:00
|
|
|
/* Removes the successor of a block with a jump. Note that the jump to be
|
|
|
|
* eliminated may be free-floating.
|
2015-07-22 03:54:22 +01:00
|
|
|
*/
|
2015-07-22 03:54:18 +01:00
|
|
|
|
2015-09-23 02:04:14 +01:00
|
|
|
static void
|
|
|
|
unlink_jump(nir_block *block, nir_jump_type type, bool add_normal_successors)
|
2015-07-22 03:54:22 +01:00
|
|
|
{
|
|
|
|
if (block->successors[0])
|
|
|
|
remove_phi_src(block->successors[0], block);
|
|
|
|
if (block->successors[1])
|
|
|
|
remove_phi_src(block->successors[1], block);
|
2015-07-22 03:54:18 +01:00
|
|
|
|
nir/cf: Alter block successors before adding a fake link.
Consider the case of "while (...) { break }". Or in NIR:
block block_0 (0x7ab640):
...
/* succs: block_1 */
loop {
block block_1:
/* preds: block_0 */
break
/* succs: block_2 */
}
block block_2:
Calling nir_handle_remove_jump(block_1, nir_jump_break) will remove the break.
Unfortunately, it would mangle the predecessors and successors.
Here, block_2->predecessors->entries == 1, so we would create a fake
link, setting block_1->successors[1] = block_2, and adding block_1 to
block_2's predecessor set. This is illegal: a block cannot specify the
same successor twice. In particular, adding the predecessor would have
no effect, as it was already present in the set.
We'd then call unlink_block_successors(), which would delete the fake
link and remove block_1 from block_2's predecessor set. It would then
delete successors[0], and attempt to remove block_1 from block_2's
predecessor set a second time...except that it wouldn't be present,
triggering an assertion failure.
The fix appears to be simple: simply unlink the block's successors and
recreate them to point at the correct blocks first. Then, add the fake
link. In the above example, removing the break would cause block_1 to
have itself as a successor (as it becomes an infinite loop), so adding
the fake link won't cause a duplicate successor.
v2: Add comments (requested by Connor Abbott) and fix commit message.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
2015-09-18 21:11:56 +01:00
|
|
|
unlink_block_successors(block);
|
|
|
|
if (add_normal_successors)
|
|
|
|
block_add_normal_succs(block);
|
2015-07-22 03:54:22 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
nir_handle_remove_jump(nir_block *block, nir_jump_type type)
|
|
|
|
{
|
2015-09-23 02:04:14 +01:00
|
|
|
unlink_jump(block, type, true);
|
2015-07-22 03:54:22 +01:00
|
|
|
|
2015-07-22 03:54:18 +01:00
|
|
|
nir_function_impl *impl = nir_cf_node_get_function(&block->cf_node);
|
|
|
|
nir_metadata_preserve(impl, nir_metadata_none);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void
|
|
|
|
update_if_uses(nir_cf_node *node)
|
|
|
|
{
|
|
|
|
if (node->type != nir_cf_node_if)
|
|
|
|
return;
|
|
|
|
|
|
|
|
nir_if *if_stmt = nir_cf_node_as_if(node);
|
|
|
|
|
|
|
|
if_stmt->condition.parent_if = if_stmt;
|
|
|
|
if (if_stmt->condition.is_ssa) {
|
|
|
|
list_addtail(&if_stmt->condition.use_link,
|
|
|
|
&if_stmt->condition.ssa->if_uses);
|
|
|
|
} else {
|
|
|
|
list_addtail(&if_stmt->condition.use_link,
|
|
|
|
&if_stmt->condition.reg.reg->if_uses);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Stitch two basic blocks together into one. The aggregate must have the same
|
|
|
|
* predecessors as the first and the same successors as the second.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void
|
|
|
|
stitch_blocks(nir_block *before, nir_block *after)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* We move after into before, so we have to deal with up to 2 successors vs.
|
|
|
|
* possibly a large number of predecessors.
|
|
|
|
*
|
|
|
|
* TODO: special case when before is empty and after isn't?
|
|
|
|
*/
|
|
|
|
|
2018-08-24 15:34:05 +01:00
|
|
|
if (nir_block_ends_in_jump(before)) {
|
2015-07-22 03:54:26 +01:00
|
|
|
assert(exec_list_is_empty(&after->instr_list));
|
|
|
|
if (after->successors[0])
|
|
|
|
remove_phi_src(after->successors[0], after);
|
|
|
|
if (after->successors[1])
|
|
|
|
remove_phi_src(after->successors[1], after);
|
|
|
|
unlink_block_successors(after);
|
|
|
|
exec_node_remove(&after->cf_node.node);
|
|
|
|
} else {
|
|
|
|
move_successors(after, before);
|
2015-07-22 03:54:18 +01:00
|
|
|
|
2015-07-22 03:54:26 +01:00
|
|
|
foreach_list_typed(nir_instr, instr, node, &after->instr_list) {
|
|
|
|
instr->block = before;
|
|
|
|
}
|
2015-07-22 03:54:18 +01:00
|
|
|
|
2015-07-22 03:54:26 +01:00
|
|
|
exec_list_append(&before->instr_list, &after->instr_list);
|
|
|
|
exec_node_remove(&after->cf_node.node);
|
|
|
|
}
|
2015-07-22 03:54:18 +01:00
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:33 +01:00
|
|
|
void
|
|
|
|
nir_cf_node_insert(nir_cursor cursor, nir_cf_node *node)
|
|
|
|
{
|
|
|
|
nir_block *before, *after;
|
|
|
|
|
|
|
|
split_block_cursor(cursor, &before, &after);
|
|
|
|
|
|
|
|
if (node->type == nir_cf_node_block) {
|
|
|
|
nir_block *block = nir_cf_node_as_block(node);
|
|
|
|
exec_node_insert_after(&before->cf_node.node, &block->cf_node.node);
|
|
|
|
block->cf_node.parent = before->cf_node.parent;
|
|
|
|
/* stitch_blocks() assumes that any block that ends with a jump has
|
|
|
|
* already been setup with the correct successors, so we need to set
|
|
|
|
* up jumps here as the block is being inserted.
|
|
|
|
*/
|
2018-08-24 15:34:05 +01:00
|
|
|
if (nir_block_ends_in_jump(block))
|
2015-07-22 03:54:33 +01:00
|
|
|
nir_handle_add_jump(block);
|
|
|
|
|
|
|
|
stitch_blocks(block, after);
|
|
|
|
stitch_blocks(before, block);
|
|
|
|
} else {
|
|
|
|
update_if_uses(node);
|
|
|
|
insert_non_block(before, node, after);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:27 +01:00
|
|
|
static bool
|
|
|
|
replace_ssa_def_uses(nir_ssa_def *def, void *void_impl)
|
|
|
|
{
|
|
|
|
nir_function_impl *impl = void_impl;
|
|
|
|
void *mem_ctx = ralloc_parent(impl);
|
|
|
|
|
|
|
|
nir_ssa_undef_instr *undef =
|
2016-03-23 07:04:09 +00:00
|
|
|
nir_ssa_undef_instr_create(mem_ctx, def->num_components,
|
|
|
|
def->bit_size);
|
2015-07-22 03:54:27 +01:00
|
|
|
nir_instr_insert_before_cf_list(&impl->body, &undef->instr);
|
2015-09-09 21:24:35 +01:00
|
|
|
nir_ssa_def_rewrite_uses(def, nir_src_for_ssa(&undef->def));
|
2015-07-22 03:54:27 +01:00
|
|
|
return true;
|
|
|
|
}
|
2015-07-22 03:54:18 +01:00
|
|
|
|
|
|
|
static void
|
2015-07-22 03:54:27 +01:00
|
|
|
cleanup_cf_node(nir_cf_node *node, nir_function_impl *impl)
|
2015-07-22 03:54:18 +01:00
|
|
|
{
|
|
|
|
switch (node->type) {
|
|
|
|
case nir_cf_node_block: {
|
|
|
|
nir_block *block = nir_cf_node_as_block(node);
|
|
|
|
/* We need to walk the instructions and clean up defs/uses */
|
2016-04-27 02:34:19 +01:00
|
|
|
nir_foreach_instr_safe(instr, block) {
|
2015-07-22 03:54:28 +01:00
|
|
|
if (instr->type == nir_instr_type_jump) {
|
|
|
|
nir_jump_type jump_type = nir_instr_as_jump(instr)->type;
|
2015-09-23 02:04:14 +01:00
|
|
|
unlink_jump(block, jump_type, false);
|
2015-07-22 03:54:28 +01:00
|
|
|
} else {
|
2015-07-22 03:54:27 +01:00
|
|
|
nir_foreach_ssa_def(instr, replace_ssa_def_uses, impl);
|
2015-07-22 03:54:18 +01:00
|
|
|
nir_instr_remove(instr);
|
2015-07-22 03:54:27 +01:00
|
|
|
}
|
|
|
|
}
|
2015-07-22 03:54:18 +01:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
case nir_cf_node_if: {
|
|
|
|
nir_if *if_stmt = nir_cf_node_as_if(node);
|
|
|
|
foreach_list_typed(nir_cf_node, child, node, &if_stmt->then_list)
|
2015-07-22 03:54:27 +01:00
|
|
|
cleanup_cf_node(child, impl);
|
2015-07-22 03:54:18 +01:00
|
|
|
foreach_list_typed(nir_cf_node, child, node, &if_stmt->else_list)
|
2015-07-22 03:54:27 +01:00
|
|
|
cleanup_cf_node(child, impl);
|
2015-07-22 03:54:18 +01:00
|
|
|
|
|
|
|
list_del(&if_stmt->condition.use_link);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
case nir_cf_node_loop: {
|
|
|
|
nir_loop *loop = nir_cf_node_as_loop(node);
|
|
|
|
foreach_list_typed(nir_cf_node, child, node, &loop->body)
|
2015-07-22 03:54:27 +01:00
|
|
|
cleanup_cf_node(child, impl);
|
2015-07-22 03:54:18 +01:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
case nir_cf_node_function: {
|
|
|
|
nir_function_impl *impl = nir_cf_node_as_function(node);
|
|
|
|
foreach_list_typed(nir_cf_node, child, node, &impl->body)
|
2015-07-22 03:54:27 +01:00
|
|
|
cleanup_cf_node(child, impl);
|
2015-07-22 03:54:18 +01:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
default:
|
|
|
|
unreachable("Invalid CF node type");
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:34 +01:00
|
|
|
void
|
|
|
|
nir_cf_extract(nir_cf_list *extracted, nir_cursor begin, nir_cursor end)
|
|
|
|
{
|
|
|
|
nir_block *block_begin, *block_end, *block_before, *block_after;
|
|
|
|
|
2015-12-24 02:10:08 +00:00
|
|
|
if (nir_cursors_equal(begin, end)) {
|
|
|
|
exec_list_make_empty(&extracted->list);
|
|
|
|
extracted->impl = NULL; /* we shouldn't need this */
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2015-07-22 03:54:34 +01:00
|
|
|
/* In the case where begin points to an instruction in some basic block and
|
|
|
|
* end points to the end of the same basic block, we rely on the fact that
|
|
|
|
* splitting on an instruction moves earlier instructions into a new basic
|
|
|
|
* block. If the later instructions were moved instead, then the end cursor
|
|
|
|
* would be pointing to the same place that begin used to point to, which
|
|
|
|
* is obviously not what we want.
|
|
|
|
*/
|
|
|
|
split_block_cursor(begin, &block_before, &block_begin);
|
|
|
|
split_block_cursor(end, &block_end, &block_after);
|
|
|
|
|
|
|
|
extracted->impl = nir_cf_node_get_function(&block_begin->cf_node);
|
|
|
|
exec_list_make_empty(&extracted->list);
|
|
|
|
|
2015-09-19 12:40:07 +01:00
|
|
|
/* Dominance and other block-related information is toast. */
|
|
|
|
nir_metadata_preserve(extracted->impl, nir_metadata_none);
|
|
|
|
|
2015-07-22 03:54:34 +01:00
|
|
|
nir_cf_node *cf_node = &block_begin->cf_node;
|
|
|
|
nir_cf_node *cf_node_end = &block_end->cf_node;
|
|
|
|
while (true) {
|
|
|
|
nir_cf_node *next = nir_cf_node_next(cf_node);
|
|
|
|
|
|
|
|
exec_node_remove(&cf_node->node);
|
|
|
|
cf_node->parent = NULL;
|
|
|
|
exec_list_push_tail(&extracted->list, &cf_node->node);
|
|
|
|
|
|
|
|
if (cf_node == cf_node_end)
|
|
|
|
break;
|
|
|
|
|
|
|
|
cf_node = next;
|
|
|
|
}
|
|
|
|
|
|
|
|
stitch_blocks(block_before, block_after);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
nir_cf_reinsert(nir_cf_list *cf_list, nir_cursor cursor)
|
|
|
|
{
|
|
|
|
nir_block *before, *after;
|
|
|
|
|
2015-12-24 02:10:08 +00:00
|
|
|
if (exec_list_is_empty(&cf_list->list))
|
|
|
|
return;
|
|
|
|
|
2015-07-22 03:54:34 +01:00
|
|
|
split_block_cursor(cursor, &before, &after);
|
|
|
|
|
|
|
|
foreach_list_typed_safe(nir_cf_node, node, node, &cf_list->list) {
|
|
|
|
exec_node_remove(&node->node);
|
|
|
|
node->parent = before->cf_node.parent;
|
|
|
|
exec_node_insert_node_before(&after->cf_node.node, &node->node);
|
|
|
|
}
|
|
|
|
|
|
|
|
stitch_blocks(before,
|
|
|
|
nir_cf_node_as_block(nir_cf_node_next(&before->cf_node)));
|
|
|
|
stitch_blocks(nir_cf_node_as_block(nir_cf_node_prev(&after->cf_node)),
|
|
|
|
after);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
nir_cf_delete(nir_cf_list *cf_list)
|
|
|
|
{
|
|
|
|
foreach_list_typed(nir_cf_node, node, node, &cf_list->list) {
|
|
|
|
cleanup_cf_node(node, cf_list->impl);
|
|
|
|
}
|
|
|
|
}
|