| /* |
| * Copyright © 2013 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. |
| */ |
| |
| /** |
| * \file opt_flatten_nested_if_blocks.cpp |
| * |
| * Flattens nested if blocks such as: |
| * |
| * if (x) { |
| * if (y) { |
| * ... |
| * } |
| * } |
| * |
| * into a single if block with a combined condition: |
| * |
| * if (x && y) { |
| * ... |
| * } |
| */ |
| |
| #include "ir.h" |
| #include "ir_builder.h" |
| |
| using namespace ir_builder; |
| |
| namespace { |
| |
| class nested_if_flattener : public ir_hierarchical_visitor { |
| public: |
| nested_if_flattener() |
| { |
| progress = false; |
| } |
| |
| ir_visitor_status visit_leave(ir_if *); |
| ir_visitor_status visit_enter(ir_assignment *); |
| |
| bool progress; |
| }; |
| |
| } /* unnamed namespace */ |
| |
| /* We only care about the top level "if" instructions, so don't |
| * descend into expressions. |
| */ |
| ir_visitor_status |
| nested_if_flattener::visit_enter(ir_assignment *ir) |
| { |
| (void) ir; |
| return visit_continue_with_parent; |
| } |
| |
| bool |
| opt_flatten_nested_if_blocks(exec_list *instructions) |
| { |
| nested_if_flattener v; |
| |
| v.run(instructions); |
| return v.progress; |
| } |
| |
| |
| ir_visitor_status |
| nested_if_flattener::visit_leave(ir_if *ir) |
| { |
| /* Only handle a single ir_if within the then clause of an ir_if. No extra |
| * instructions, no else clauses, nothing. |
| */ |
| if (ir->then_instructions.is_empty() || !ir->else_instructions.is_empty()) |
| return visit_continue; |
| |
| ir_if *inner = ((ir_instruction *) ir->then_instructions.get_head_raw())->as_if(); |
| if (!inner || !inner->next->is_tail_sentinel() || |
| !inner->else_instructions.is_empty()) |
| return visit_continue; |
| |
| ir->condition = logic_and(ir->condition, inner->condition); |
| inner->then_instructions.move_nodes_to(&ir->then_instructions); |
| |
| progress = true; |
| return visit_continue; |
| } |