diff options
Diffstat (limited to 'src/glsl')
| -rw-r--r-- | src/glsl/Makefile | 1 | ||||
| -rw-r--r-- | src/glsl/ir_if_return.cpp | 123 | ||||
| -rw-r--r-- | src/glsl/ir_optimization.h | 1 |
3 files changed, 125 insertions, 0 deletions
diff --git a/src/glsl/Makefile b/src/glsl/Makefile index d2a687aa335..ddc9d82d61f 100644 --- a/src/glsl/Makefile +++ b/src/glsl/Makefile @@ -40,6 +40,7 @@ CXX_SOURCES = \ ir_function_inlining.cpp \ ir_hierarchical_visitor.cpp \ ir_hv_accept.cpp \ + ir_if_return.cpp \ ir_if_simplification.cpp \ ir_mod_to_fract.cpp \ ir_print_visitor.cpp \ diff --git a/src/glsl/ir_if_return.cpp b/src/glsl/ir_if_return.cpp new file mode 100644 index 00000000000..f68dcfb5010 --- /dev/null +++ b/src/glsl/ir_if_return.cpp @@ -0,0 +1,123 @@ +/* + * 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_if_return.cpp + * + * If a function includes an if statement that returns from both + * branches, then make the branches write the return val to a temp and + * return the temp after the if statement. + * + * This allows inlinining in the common case of short functions that + * return one of two values based on a condition. This helps on + * hardware with no branching support, and may even be a useful + * transform on hardware supporting control flow by masked returns + * with normal returns. + */ + +#include "ir.h" + +class ir_if_return_visitor : public ir_hierarchical_visitor { +public: + ir_if_return_visitor() + { + this->progress = false; + } + + ir_visitor_status visit_enter(ir_if *); + + bool progress; +}; + +bool +do_if_return(exec_list *instructions) +{ + ir_if_return_visitor v; + + visit_list_elements(&v, instructions); + + return v.progress; +} + + +ir_visitor_status +ir_if_return_visitor::visit_enter(ir_if *ir) +{ + ir_return *then_return = NULL; + ir_return *else_return = NULL; + + /* Try to find a return statement on both sides. */ + foreach_iter(exec_list_iterator, then_iter, ir->then_instructions) { + ir_instruction *then_ir = (ir_instruction *)then_iter.get(); + then_return = then_ir->as_return(); + if (then_return) + break; + } + if (!then_return) + return visit_continue; + + foreach_iter(exec_list_iterator, else_iter, ir->else_instructions) { + ir_instruction *else_ir = (ir_instruction *)else_iter.get(); + else_return = else_ir->as_return(); + if (else_return) + break; + } + if (!else_return) + return visit_continue; + + /* Trim off any trailing instructions after the return statements + * on both sides. + */ + while (then_return->get_next()->get_next()) + ((ir_instruction *)then_return->get_next())->remove(); + while (else_return->get_next()->get_next()) + ((ir_instruction *)else_return->get_next())->remove(); + + this->progress = true; + + if (!then_return->value) { + then_return->remove(); + else_return->remove(); + ir->insert_after(new(ir) ir_return(NULL)); + } else { + ir_assignment *assign; + ir_variable *new_var = new(ir) ir_variable(then_return->value->type, + "if_return_tmp"); + ir->insert_before(new_var); + + assign = new(ir) ir_assignment(new(ir) ir_dereference_variable(new_var), + then_return->value, NULL); + then_return->insert_before(assign); + then_return->remove(); + + assign = new(ir) ir_assignment(new(ir) ir_dereference_variable(new_var), + else_return->value, NULL); + else_return->insert_before(assign); + else_return->remove(); + + ir_dereference_variable *deref = new(ir) ir_dereference_variable(new_var); + ir->insert_after(new(ir) ir_return(deref)); + } + + return visit_continue; +} diff --git a/src/glsl/ir_optimization.h b/src/glsl/ir_optimization.h index 93010dadbee..b03c0644cf0 100644 --- a/src/glsl/ir_optimization.h +++ b/src/glsl/ir_optimization.h @@ -39,6 +39,7 @@ bool do_dead_code_unlinked(struct _mesa_glsl_parse_state *state, exec_list *instructions); bool do_div_to_mul_rcp(exec_list *instructions); bool do_function_inlining(exec_list *instructions); +bool do_if_return(exec_list *instructions); bool do_if_simplification(exec_list *instructions); bool do_mod_to_fract(exec_list *instructions); bool do_swizzle_swizzle(exec_list *instructions); |