From 30f51f1a1a70bc838d5bed449daff0dd9f2e8ef2 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Wed, 22 Oct 2014 20:48:21 -0700 Subject: [PATCH] glsl: Optimize "if (cond) discard;" to a conditional discard. st_glsl_to_tgsi and ir_to_mesa have handled conditional discards for a long time; the previous patch added that capability to i965. i965 (Haswell) shader-db stats: Without NIR: total instructions in shared programs: 5792133 -> 5776360 (-0.27%) instructions in affected programs: 737585 -> 721812 (-2.14%) helped: 6300 HURT: 68 GAINED: 2 With NIR: total instructions in shared programs: 5787538 -> 5769569 (-0.31%) instructions in affected programs: 767843 -> 749874 (-2.34%) helped: 6522 HURT: 35 GAINED: 6 Signed-off-by: Kenneth Graunke Reviewed-by: Connor Abbott Reviewed-by: Matt Turner Reviewed-by: Eric Anholt --- src/glsl/Makefile.sources | 1 + src/glsl/glsl_parser_extras.cpp | 1 + src/glsl/ir_optimization.h | 1 + src/glsl/opt_conditional_discard.cpp | 81 ++++++++++++++++++++++++++++ 4 files changed, 84 insertions(+) create mode 100644 src/glsl/opt_conditional_discard.cpp diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources index d0210d1705f..b876642e859 100644 --- a/src/glsl/Makefile.sources +++ b/src/glsl/Makefile.sources @@ -157,6 +157,7 @@ LIBGLSL_FILES = \ lower_ubo_reference.cpp \ opt_algebraic.cpp \ opt_array_splitting.cpp \ + opt_conditional_discard.cpp \ opt_constant_folding.cpp \ opt_constant_propagation.cpp \ opt_constant_variable.cpp \ diff --git a/src/glsl/glsl_parser_extras.cpp b/src/glsl/glsl_parser_extras.cpp index 9f793138009..f19804b7238 100644 --- a/src/glsl/glsl_parser_extras.cpp +++ b/src/glsl/glsl_parser_extras.cpp @@ -1627,6 +1627,7 @@ do_common_optimization(exec_list *ir, bool linked, } progress = do_if_simplification(ir) || progress; progress = opt_flatten_nested_if_blocks(ir) || progress; + progress = opt_conditional_discard(ir) || progress; progress = do_copy_propagation(ir) || progress; progress = do_copy_propagation_elements(ir) || progress; diff --git a/src/glsl/ir_optimization.h b/src/glsl/ir_optimization.h index 7eb861ae560..e6939f3fe1f 100644 --- a/src/glsl/ir_optimization.h +++ b/src/glsl/ir_optimization.h @@ -77,6 +77,7 @@ bool do_common_optimization(exec_list *ir, bool linked, bool do_rebalance_tree(exec_list *instructions); bool do_algebraic(exec_list *instructions, bool native_integers, const struct gl_shader_compiler_options *options); +bool opt_conditional_discard(exec_list *instructions); bool do_constant_folding(exec_list *instructions); bool do_constant_variable(exec_list *instructions); bool do_constant_variable_unlinked(exec_list *instructions); diff --git a/src/glsl/opt_conditional_discard.cpp b/src/glsl/opt_conditional_discard.cpp new file mode 100644 index 00000000000..8a3ad24873e --- /dev/null +++ b/src/glsl/opt_conditional_discard.cpp @@ -0,0 +1,81 @@ +/* + * Copyright © 2014 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_conditional_discard.cpp + * + * Replace + * + * if (cond) discard; + * + * with + * + * (discard ) + */ + +#include "glsl_types.h" +#include "ir.h" + +namespace { + +class opt_conditional_discard_visitor : public ir_hierarchical_visitor { +public: + opt_conditional_discard_visitor() + { + progress = false; + } + + ir_visitor_status visit_leave(ir_if *); + + bool progress; +}; + +} /* anonymous namespace */ + +bool +opt_conditional_discard(exec_list *instructions) +{ + opt_conditional_discard_visitor v; + v.run(instructions); + return v.progress; +} + +ir_visitor_status +opt_conditional_discard_visitor::visit_leave(ir_if *ir) +{ + /* Look for "if (...) discard" with no else clause or extra statements. */ + if (ir->then_instructions.is_empty() || + !ir->then_instructions.head->next->is_tail_sentinel() || + !((ir_instruction *) ir->then_instructions.head)->as_discard() || + !ir->else_instructions.is_empty()) + return visit_continue; + + /* Move the condition and replace the ir_if with the ir_discard. */ + ir_discard *discard = (ir_discard *) ir->then_instructions.head; + discard->condition = ir->condition; + ir->replace_with(discard); + + progress = true; + + return visit_continue; +} -- 2.30.2