From 747ddc3cdd51cc3786894e2ba56d86334a7051a5 Mon Sep 17 00:00:00 2001 From: Connor Abbott Date: Tue, 21 Jul 2015 19:54:22 -0700 Subject: [PATCH] nir/cf: split up and improve nir_handle_remove_jumps() Before, the process of removing a jump and wiring up the remaining block correctly was atomic, but with the new control flow modification it's split into two parts: first, we extract the jump, which creates a new block with re-wired successors as well as a free-floating jump, and then we delete the control flow containing the jump, which removes the entry in the predecessors and any phi node sources. Split up nir_handle_remove_jumps() to accomodate this, and add the missing support for removing phi node sources. Signed-off-by: Connor Abbott Reviewed-by: Kenneth Graunke --- src/glsl/nir/nir_control_flow.c | 135 ++++++++++++++++++++++++---------------- 1 file changed, 81 insertions(+), 54 deletions(-) diff --git a/src/glsl/nir/nir_control_flow.c b/src/glsl/nir/nir_control_flow.c index bf25813..205b608 100644 --- a/src/glsl/nir/nir_control_flow.c +++ b/src/glsl/nir/nir_control_flow.c @@ -280,6 +280,61 @@ move_successors(nir_block *source, nir_block *dest) link_blocks(dest, succ1, succ2); } +/* Given a basic block with no successors that has been inserted into the + * control flow tree, gives it the successors it would normally have assuming + * it doesn't end in a jump instruction. Also inserts phi sources with undefs + * if necessary. + */ +static void +block_add_normal_succs(nir_block *block) +{ + if (exec_node_is_tail_sentinel(block->cf_node.node.next)) { + nir_cf_node *parent = block->cf_node.parent; + if (parent->type == nir_cf_node_if) { + nir_cf_node *next = nir_cf_node_next(parent); + assert(next->type == nir_cf_node_block); + nir_block *next_block = nir_cf_node_as_block(next); + + link_blocks(block, next_block, NULL); + } else { + assert(parent->type == nir_cf_node_loop); + nir_loop *loop = nir_cf_node_as_loop(parent); + + nir_cf_node *head = nir_loop_first_cf_node(loop); + assert(head->type == nir_cf_node_block); + nir_block *head_block = nir_cf_node_as_block(head); + + link_blocks(block, head_block, NULL); + insert_phi_undef(head_block, block); + } + } 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); + + nir_cf_node *first_then = nir_if_first_then_node(next_if); + assert(first_then->type == nir_cf_node_block); + nir_block *first_then_block = nir_cf_node_as_block(first_then); + + nir_cf_node *first_else = nir_if_first_else_node(next_if); + assert(first_else->type == nir_cf_node_block); + nir_block *first_else_block = nir_cf_node_as_block(first_else); + + link_blocks(block, first_then_block, first_else_block); + } else { + assert(next->type == nir_cf_node_loop); + nir_loop *next_loop = nir_cf_node_as_loop(next); + + nir_cf_node *first = nir_loop_first_cf_node(next_loop); + assert(first->type == nir_cf_node_block); + nir_block *first_block = nir_cf_node_as_block(first); + + link_blocks(block, first_block, NULL); + insert_phi_undef(first_block, block); + } + } +} + static nir_block * split_block_end(nir_block *block) { @@ -390,73 +445,45 @@ remove_phi_src(nir_block *block, nir_block *pred) } } -void -nir_handle_remove_jump(nir_block *block, nir_jump_type type) -{ - unlink_block_successors(block); - - if (exec_node_is_tail_sentinel(block->cf_node.node.next)) { - nir_cf_node *parent = block->cf_node.parent; - if (parent->type == nir_cf_node_if) { - nir_cf_node *next = nir_cf_node_next(parent); - assert(next->type == nir_cf_node_block); - nir_block *next_block = nir_cf_node_as_block(next); - - link_blocks(block, next_block, NULL); - } else { - assert(parent->type == nir_cf_node_loop); - nir_loop *loop = nir_cf_node_as_loop(parent); - - nir_cf_node *head = nir_loop_first_cf_node(loop); - assert(head->type == nir_cf_node_block); - nir_block *head_block = nir_cf_node_as_block(head); - - link_blocks(block, head_block, NULL); - } - } 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); - - nir_cf_node *first_then = nir_if_first_then_node(next_if); - assert(first_then->type == nir_cf_node_block); - nir_block *first_then_block = nir_cf_node_as_block(first_then); - - nir_cf_node *first_else = nir_if_first_else_node(next_if); - assert(first_else->type == nir_cf_node_block); - nir_block *first_else_block = nir_cf_node_as_block(first_else); - - link_blocks(block, first_then_block, first_else_block); - } else { - assert(next->type == nir_cf_node_loop); - nir_loop *next_loop = nir_cf_node_as_loop(next); - - nir_cf_node *first = nir_loop_first_cf_node(next_loop); - assert(first->type == nir_cf_node_block); - nir_block *first_block = nir_cf_node_as_block(first); +/* Removes the successor of a block with a jump, and inserts a fake edge for + * infinite loops. Note that the jump to be eliminated may be free-floating. + */ - link_blocks(block, first_block, NULL); - } - } +static +void unlink_jump(nir_block *block, nir_jump_type type) +{ + if (block->successors[0]) + remove_phi_src(block->successors[0], block); + if (block->successors[1]) + remove_phi_src(block->successors[1], block); if (type == nir_jump_break) { - nir_loop *loop = nearest_loop(&block->cf_node); + nir_block *next = block->successors[0]; - nir_cf_node *next = nir_cf_node_next(&loop->cf_node); - assert(next->type == nir_cf_node_block); - nir_block *next_block = nir_cf_node_as_block(next); + if (next->predecessors->entries == 1) { + nir_loop *loop = + nir_cf_node_as_loop(nir_cf_node_prev(&next->cf_node)); - if (next_block->predecessors->entries == 0) { /* insert fake link */ nir_cf_node *last = nir_loop_last_cf_node(loop); assert(last->type == nir_cf_node_block); nir_block *last_block = nir_cf_node_as_block(last); - last_block->successors[1] = next_block; - block_add_pred(next_block, last_block); + last_block->successors[1] = next; + block_add_pred(next, last_block); } } + unlink_block_successors(block); +} + +void +nir_handle_remove_jump(nir_block *block, nir_jump_type type) +{ + unlink_jump(block, type); + + block_add_normal_succs(block); + nir_function_impl *impl = nir_cf_node_get_function(&block->cf_node); nir_metadata_preserve(impl, nir_metadata_none); } -- 2.7.4