| 0,0 → 1,180 |
|---|
| /* |
| * Copyright © 2010 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_discard_simplification.cpp |
| * |
| * This pass simplifies if-statements and loops containing unconditional |
| * discards. |
| * |
| * Case 1: Both branches contain unconditional discards: |
| * ----------------------------------------------------- |
| * |
| * if (cond) { |
| * s1; |
| * discard; |
| * s2; |
| * } else { |
| * s3; |
| * discard; |
| * s4; |
| * } |
| * |
| * becomes: |
| * |
| * discard |
| * |
| * Case 2: The "then" clause contains an unconditional discard: |
| * ------------------------------------------------------------ |
| * |
| * if (cond) { |
| * s1; |
| * discard; |
| * s2; |
| * } else { |
| * s3; |
| * } |
| * |
| * becomes: |
| * |
| * if (cond) { |
| * discard; |
| * } else { |
| * s3; |
| * } |
| * |
| * Case 3: The "else" clause contains an unconditional discard: |
| * ------------------------------------------------------------ |
| * |
| * if (cond) { |
| * s1; |
| * } else { |
| * s2; |
| * discard; |
| * s3; |
| * } |
| * |
| * becomes: |
| * |
| * if (cond) { |
| * s1; |
| * } else { |
| * discard; |
| * } |
| */ |
| |
| #include "glsl_types.h" |
| #include "ir.h" |
| |
| class discard_simplifier : public ir_hierarchical_visitor { |
| public: |
| discard_simplifier() |
| { |
| this->progress = false; |
| } |
| |
| ir_visitor_status visit_enter(ir_if *); |
| ir_visitor_status visit_enter(ir_loop *); |
| |
| bool progress; |
| }; |
| |
| static ir_discard * |
| find_unconditional_discard(exec_list &instructions) |
| { |
| foreach_list(n, &instructions) { |
| ir_discard *ir = ((ir_instruction *) n)->as_discard(); |
| if (ir != NULL && ir->condition == NULL) |
| return ir; |
| } |
| return NULL; |
| } |
| |
| static bool |
| is_only_instruction(ir_discard *discard) |
| { |
| return (discard->prev->is_head_sentinel() && |
| discard->next->is_tail_sentinel()); |
| } |
| |
| ir_visitor_status |
| discard_simplifier::visit_enter(ir_if *ir) |
| { |
| ir_discard *then_discard = find_unconditional_discard(ir->then_instructions); |
| ir_discard *else_discard = find_unconditional_discard(ir->else_instructions); |
| |
| if (then_discard == NULL && else_discard == NULL) |
| return visit_continue; |
| |
| /* If both branches result in discard, replace whole if with discard. */ |
| if (then_discard != NULL && else_discard != NULL) { |
| this->progress = true; |
| ir->replace_with(then_discard); |
| return visit_continue_with_parent; |
| } |
| |
| /* Otherwise, one branch has a discard. */ |
| if (then_discard != NULL && !is_only_instruction(then_discard)) { |
| this->progress = true; |
| ir->then_instructions.make_empty(); |
| ir->then_instructions.push_tail(then_discard); |
| } else if (else_discard != NULL && !is_only_instruction(else_discard)) { |
| this->progress = true; |
| ir->else_instructions.make_empty(); |
| ir->else_instructions.push_tail(else_discard); |
| } |
| |
| visit_list_elements(this, &ir->then_instructions); |
| return visit_continue_with_parent; |
| } |
| |
| ir_visitor_status |
| discard_simplifier::visit_enter(ir_loop *ir) |
| { |
| ir_discard *discard = find_unconditional_discard(ir->body_instructions); |
| |
| if (discard) { |
| ir->replace_with(discard); |
| return visit_continue_with_parent; |
| } |
| |
| return visit_continue; |
| } |
| |
| bool |
| do_discard_simplification(exec_list *instructions) |
| { |
| /* Look for a top-level unconditional discard */ |
| ir_discard *discard = find_unconditional_discard(*instructions); |
| if (discard != NULL) { |
| instructions->make_empty(); |
| instructions->push_tail(discard); |
| return true; |
| } |
| |
| discard_simplifier v; |
| |
| visit_list_elements(&v, instructions); |
| |
| return v.progress; |
| } |