Module: Mesa Branch: main Commit: 7e842a75ac62a4d38dcaf031c373d6f0dae474fd URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=7e842a75ac62a4d38dcaf031c373d6f0dae474fd
Author: Ian Romanick <[email protected]> Date: Wed Sep 13 12:07:30 2023 -0700 intel/compiler: Don't create extra CFG links in opt_predicated_break Reviewed-by: Caio Oliveira <[email protected]> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25216> --- src/intel/compiler/brw_predicated_break.cpp | 36 +++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-) diff --git a/src/intel/compiler/brw_predicated_break.cpp b/src/intel/compiler/brw_predicated_break.cpp index ee6efb92f61..118d71b3773 100644 --- a/src/intel/compiler/brw_predicated_break.cpp +++ b/src/intel/compiler/brw_predicated_break.cpp @@ -159,6 +159,14 @@ opt_predicated_break(backend_shader *s) endif_inst->remove(endif_block); if (!earlier_block->ends_with_control_flow()) { + /* FIXME: There is a potential problem here. If earlier_block starts + * with a DO instruction, this will delete the physical link to the + * WHILE block. It is unclear whether ENDIF has the same potential + * problem. + */ + assert(earlier_block->start() == NULL || + earlier_block->start()->opcode != BRW_OPCODE_DO); + earlier_block->unlink_children(); earlier_block->add_successor(s->cfg->mem_ctx, jump_block, bblock_link_logical); @@ -167,8 +175,32 @@ opt_predicated_break(backend_shader *s) if (!later_block->starts_with_control_flow()) { later_block->unlink_parents(); } - jump_block->add_successor(s->cfg->mem_ctx, later_block, - bblock_link_logical); + + /* If jump_block already has a link to later_block, don't create another + * one. Instead, promote the link to logical. + */ + bool need_to_link = true; + foreach_list_typed(bblock_link, link, link, &jump_block->children) { + if (link->block == later_block) { + assert(later_block->starts_with_control_flow()); + + /* Update the link from later_block back to jump_block. */ + foreach_list_typed(bblock_link, parent_link, link, &later_block->parents) { + if (parent_link->block == jump_block) { + parent_link->kind = bblock_link_logical; + } + } + + /* Update the link from jump_block to later_block. */ + link->kind = bblock_link_logical; + need_to_link = false; + } + } + + if (need_to_link) { + jump_block->add_successor(s->cfg->mem_ctx, later_block, + bblock_link_logical); + } if (earlier_block->can_combine_with(jump_block)) { earlier_block->combine_with(jump_block);
