Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1901 | serge | 1 | /* |
| 2 | * Copyright © 2010 Intel Corporation |
||
| 3 | * |
||
| 4 | * Permission is hereby granted, free of charge, to any person obtaining a |
||
| 5 | * copy of this software and associated documentation files (the "Software"), |
||
| 6 | * to deal in the Software without restriction, including without limitation |
||
| 7 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
||
| 8 | * and/or sell copies of the Software, and to permit persons to whom the |
||
| 9 | * Software is furnished to do so, subject to the following conditions: |
||
| 10 | * |
||
| 11 | * The above copyright notice and this permission notice (including the next |
||
| 12 | * paragraph) shall be included in all copies or substantial portions of the |
||
| 13 | * Software. |
||
| 14 | * |
||
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
||
| 16 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
||
| 17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
||
| 18 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
||
| 19 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
||
| 20 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
||
| 21 | * DEALINGS IN THE SOFTWARE. |
||
| 22 | */ |
||
| 23 | |||
| 24 | /** |
||
| 25 | * \file opt_redundant_jumps.cpp |
||
| 26 | * Remove certain types of redundant jumps |
||
| 27 | */ |
||
| 28 | |||
| 29 | #include "ir.h" |
||
| 30 | |||
| 31 | class redundant_jumps_visitor : public ir_hierarchical_visitor { |
||
| 32 | public: |
||
| 33 | redundant_jumps_visitor() |
||
| 34 | { |
||
| 35 | this->progress = false; |
||
| 36 | } |
||
| 37 | |||
| 38 | virtual ir_visitor_status visit_leave(ir_if *); |
||
| 39 | virtual ir_visitor_status visit_leave(ir_loop *); |
||
| 40 | |||
| 41 | bool progress; |
||
| 42 | }; |
||
| 43 | |||
| 44 | |||
| 45 | ir_visitor_status |
||
| 46 | redundant_jumps_visitor::visit_leave(ir_if *ir) |
||
| 47 | { |
||
| 48 | /* If the last instruction in both branches is a 'break' or a 'continue', |
||
| 49 | * pull it out of the branches and insert it after the if-statment. Note |
||
| 50 | * that both must be the same type (either 'break' or 'continue'). |
||
| 51 | */ |
||
| 52 | ir_instruction *const last_then = |
||
| 53 | (ir_instruction *) ir->then_instructions.get_tail(); |
||
| 54 | ir_instruction *const last_else = |
||
| 55 | (ir_instruction *) ir->else_instructions.get_tail(); |
||
| 56 | |||
| 57 | if ((last_then == NULL) || (last_else == NULL)) |
||
| 58 | return visit_continue; |
||
| 59 | |||
| 60 | if ((last_then->ir_type != ir_type_loop_jump) |
||
| 61 | || (last_else->ir_type != ir_type_loop_jump)) |
||
| 62 | return visit_continue; |
||
| 63 | |||
| 64 | ir_loop_jump *const then_jump = (ir_loop_jump *) last_then; |
||
| 65 | ir_loop_jump *const else_jump = (ir_loop_jump *) last_else; |
||
| 66 | |||
| 67 | if (then_jump->mode != else_jump->mode) |
||
| 68 | return visit_continue; |
||
| 69 | |||
| 70 | then_jump->remove(); |
||
| 71 | else_jump->remove(); |
||
| 72 | this->progress = true; |
||
| 73 | |||
| 74 | ir->insert_after(then_jump); |
||
| 75 | |||
| 76 | /* If both branchs of the if-statement are now empty, remove the |
||
| 77 | * if-statement. |
||
| 78 | */ |
||
| 79 | if (ir->then_instructions.is_empty() && ir->else_instructions.is_empty()) |
||
| 80 | ir->remove(); |
||
| 81 | |||
| 82 | return visit_continue; |
||
| 83 | } |
||
| 84 | |||
| 85 | |||
| 86 | ir_visitor_status |
||
| 87 | redundant_jumps_visitor::visit_leave(ir_loop *ir) |
||
| 88 | { |
||
| 89 | /* If the last instruction of a loop body is a 'continue', remove it. |
||
| 90 | */ |
||
| 91 | ir_instruction *const last = |
||
| 92 | (ir_instruction *) ir->body_instructions.get_tail(); |
||
| 93 | |||
| 94 | if (last && (last->ir_type == ir_type_loop_jump) |
||
| 95 | && (((ir_loop_jump *) last)->mode == ir_loop_jump::jump_continue)) { |
||
| 96 | last->remove(); |
||
| 97 | this->progress = true; |
||
| 98 | } |
||
| 99 | |||
| 100 | return visit_continue; |
||
| 101 | } |
||
| 102 | |||
| 103 | |||
| 104 | bool |
||
| 105 | optimize_redundant_jumps(exec_list *instructions) |
||
| 106 | { |
||
| 107 | redundant_jumps_visitor v; |
||
| 108 | |||
| 109 | v.run(instructions); |
||
| 110 | return v.progress; |
||
| 111 | } |