diff options
Diffstat (limited to 'src/glsl/ir_sub_to_add_neg.cpp')
-rw-r--r-- | src/glsl/ir_sub_to_add_neg.cpp | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/src/glsl/ir_sub_to_add_neg.cpp b/src/glsl/ir_sub_to_add_neg.cpp new file mode 100644 index 0000000000..7ed8c1495e --- /dev/null +++ b/src/glsl/ir_sub_to_add_neg.cpp @@ -0,0 +1,76 @@ +/* + * 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 ir_sub_to_add_neg.cpp + * + * Breaks an ir_binop_sub expression down to add(op0, neg(op1)) + * + * This simplifies expression reassociation, and for many backends + * there is no subtract operation separate from adding the negation. + * For backends with native subtract operations, they will probably + * want to recognize add(op0, neg(op1)) or the other way around to + * produce a subtract anyway. + */ + +#include "ir.h" + +class ir_sub_to_add_neg_visitor : public ir_hierarchical_visitor { +public: + ir_sub_to_add_neg_visitor() + { + this->progress = false; + } + + ir_visitor_status visit_leave(ir_expression *); + + bool progress; +}; + +bool +do_sub_to_add_neg(exec_list *instructions) +{ + ir_sub_to_add_neg_visitor v; + + visit_list_elements(&v, instructions); + return v.progress; +} + +ir_visitor_status +ir_sub_to_add_neg_visitor::visit_leave(ir_expression *ir) +{ + if (ir->operation != ir_binop_sub) + return visit_continue; + + void *mem_ctx = talloc_parent(ir); + + ir->operation = ir_binop_add; + ir->operands[1] = new(mem_ctx) ir_expression(ir_unop_neg, + ir->operands[1]->type, + ir->operands[1], + NULL); + + this->progress = true; + + return visit_continue; +} |