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046bef2357
I introduced this for ir_dead_code to distinguish function parameter outvals from varying outputs. Only, since ast_to_hir's current_function is unset when setting up function parameters (they're needed for making the function signature in the first place), all function parameter outvals were marked as shader outputs anyway. This meant that an inlined function's cloned outval was marked as a shader output and couldn't be dead-code eliminated. Instead, since ir_dead_code doesn't even look at function parameters, just use var->mode. The longest Mesa IR coming out of ir_to_mesa for Yo Frankie drops from 725 instructions to 636.
115 lines
3.6 KiB
C++
115 lines
3.6 KiB
C++
/*
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* Copyright © 2010 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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/**
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* \file ir_dead_code.cpp
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*
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* Eliminates dead assignments and variable declarations from the code.
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*/
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#include "ir.h"
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#include "ir_visitor.h"
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#include "ir_variable_refcount.h"
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#include "glsl_types.h"
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/**
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* Do a dead code pass over instructions and everything that instructions
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* references.
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*
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* Note that this will remove assignments to globals, so it is not suitable
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* for usage on an unlinked instruction stream.
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*/
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bool
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do_dead_code(exec_list *instructions)
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{
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ir_variable_refcount_visitor v;
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bool progress = false;
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v.run(instructions);
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foreach_iter(exec_list_iterator, iter, v.variable_list) {
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variable_entry *entry = (variable_entry *)iter.get();
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/* Since each assignment is a reference, the refereneced count must be
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* greater than or equal to the assignment count. If they are equal,
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* then all of the references are assignments, and the variable is
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* dead.
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*
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* Note that if the variable is neither assigned nor referenced, both
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* counts will be zero and will be caught by the equality test.
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*/
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assert(entry->referenced_count >= entry->assigned_count);
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if ((entry->referenced_count > entry->assigned_count)
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|| !entry->declaration)
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continue;
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if (entry->assign) {
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/* Remove a single dead assignment to the variable we found.
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* Don't do so if it's a shader output, though.
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*/
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if (entry->var->mode != ir_var_out &&
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entry->var->mode != ir_var_inout) {
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entry->assign->remove();
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progress = true;
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}
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} else {
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/* If there are no assignments or references to the variable left,
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* then we can remove its declaration.
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*/
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entry->var->remove();
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progress = true;
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}
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}
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talloc_free(v.mem_ctx);
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return progress;
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}
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/**
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* Does a dead code pass on the functions present in the instruction stream.
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*
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* This is suitable for use while the program is not linked, as it will
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* ignore variable declarations (and the assignments to them) for variables
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* with global scope.
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*/
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bool
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do_dead_code_unlinked(exec_list *instructions)
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{
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bool progress = false;
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foreach_iter(exec_list_iterator, iter, *instructions) {
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ir_instruction *ir = (ir_instruction *)iter.get();
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ir_function *f = ir->as_function();
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if (f) {
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foreach_iter(exec_list_iterator, sigiter, *f) {
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ir_function_signature *sig =
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(ir_function_signature *) sigiter.get();
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if (do_dead_code(&sig->body))
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progress = true;
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}
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}
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}
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return progress;
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}
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