From: Jason Ekstrand Date: Thu, 17 Mar 2016 20:58:40 +0000 (-0700) Subject: glsl: Add a pass to propagate the "invariant" and "precise" qualifiers X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=89b604922d2fb50ca1013473b2003227d61507cd;p=mesa.git glsl: Add a pass to propagate the "invariant" and "precise" qualifiers Reviewed-by: Francisco Jerez --- diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources index 9f3bcf0255b..6ab0aa7b896 100644 --- a/src/compiler/Makefile.sources +++ b/src/compiler/Makefile.sources @@ -129,6 +129,7 @@ LIBGLSL_FILES = \ glsl/opt_tree_grafting.cpp \ glsl/opt_vectorize.cpp \ glsl/program.h \ + glsl/propagate_invariance.cpp \ glsl/s_expression.cpp \ glsl/s_expression.h diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp index 1c6cd43cd68..9fcca211a99 100644 --- a/src/compiler/glsl/glsl_parser_extras.cpp +++ b/src/compiler/glsl/glsl_parser_extras.cpp @@ -1885,6 +1885,7 @@ do_common_optimization(exec_list *ir, bool linked, OPT(do_dead_functions, ir); OPT(do_structure_splitting, ir); } + propagate_invariance(ir); OPT(do_if_simplification, ir); OPT(opt_flatten_nested_if_blocks, ir); OPT(opt_conditional_discard, ir); diff --git a/src/compiler/glsl/ir_optimization.h b/src/compiler/glsl/ir_optimization.h index 2d773760f90..f9599a39ff5 100644 --- a/src/compiler/glsl/ir_optimization.h +++ b/src/compiler/glsl/ir_optimization.h @@ -139,6 +139,7 @@ bool lower_tess_level(gl_shader *shader); bool lower_vertex_id(gl_shader *shader); bool lower_subroutine(exec_list *instructions, struct _mesa_glsl_parse_state *state); +void propagate_invariance(exec_list *instructions); ir_rvalue * compare_index_block(exec_list *instructions, ir_variable *index, diff --git a/src/compiler/glsl/propagate_invariance.cpp b/src/compiler/glsl/propagate_invariance.cpp new file mode 100644 index 00000000000..c137ff3324c --- /dev/null +++ b/src/compiler/glsl/propagate_invariance.cpp @@ -0,0 +1,125 @@ +/* + * Copyright © 2016 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 propagate_invariance.cpp + * Propagate the "invariant" and "precise" qualifiers to variables used to + * compute invariant or precise values. + * + * The GLSL spec (depending on what version you read) says, among the + * conditions for geting bit-for-bit the same values on an invariant output: + * + * "All operations in the consuming expressions and any intermediate + * expressions must be the same, with the same order of operands and same + * associativity, to give the same order of evaluation." + * + * This effectively means that if a variable is used to compute an invariant + * value then that variable becomes invariant. The same should apply to the + * "precise" qualifier. + */ + +#include "ir.h" +#include "ir_visitor.h" +#include "ir_rvalue_visitor.h" +#include "ir_optimization.h" +#include "compiler/glsl_types.h" + +namespace { + +class ir_invariance_propagation_visitor : public ir_hierarchical_visitor { +public: + ir_invariance_propagation_visitor() + { + this->progress = false; + this->dst_var = NULL; + } + + virtual ~ir_invariance_propagation_visitor() + { + /* empty */ + } + + virtual ir_visitor_status visit_enter(ir_assignment *ir); + virtual ir_visitor_status visit_leave(ir_assignment *ir); + virtual ir_visitor_status visit(ir_dereference_variable *ir); + + ir_variable *dst_var; + bool progress; +}; + +} /* unnamed namespace */ + +ir_visitor_status +ir_invariance_propagation_visitor::visit_enter(ir_assignment *ir) +{ + assert(this->dst_var == NULL); + ir_variable *var = ir->lhs->variable_referenced(); + if (var->data.invariant || var->data.precise) { + this->dst_var = var; + return visit_continue; + } else { + return visit_continue_with_parent; + } +} + +ir_visitor_status +ir_invariance_propagation_visitor::visit_leave(ir_assignment *ir) +{ + this->dst_var = NULL; + + return visit_continue; +} + +ir_visitor_status +ir_invariance_propagation_visitor::visit(ir_dereference_variable *ir) +{ + if (this->dst_var == NULL) + return visit_continue; + + if (this->dst_var->data.invariant) { + if (!ir->var->data.invariant) + this->progress = true; + + ir->var->data.invariant = true; + } + + if (this->dst_var->data.precise) { + if (!ir->var->data.precise) + this->progress = true; + + ir->var->data.precise = true; + } + + return visit_continue; +} + +void +propagate_invariance(exec_list *instructions) +{ + ir_invariance_propagation_visitor visitor; + + do { + visitor.progress = false; + visit_list_elements(&visitor, instructions); + } while (visitor.progress); +}