From 7f39c9f24eee4ef189f642097249473d2041f742 Mon Sep 17 00:00:00 2001 From: Emma Anholt Date: Thu, 2 Mar 2023 15:40:20 -0800 Subject: [PATCH] glsl: Delete constant propagation pass. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit freedreno results look like noise. Excerpts: total instructions in shared programs: 2718355 -> 2718343 (<.01%) instructions in affected programs: 2001 -> 1989 (-0.60%) total last-baryf in shared programs: 109960 -> 109992 (0.03%) last-baryf in affected programs: 789 -> 821 (4.06%) total sstall in shared programs: 198273 -> 198312 (0.02%) sstall in affected programs: 140 -> 179 (27.86%) total systall in shared programs: 432224 -> 432163 (-0.01%) systall in affected programs: 241 -> 180 (-25.31%) Reviewed-by: Alyssa Rosenzweig Reviewed-by: Timothy Arceri Reviewed-by: Marek Olšák Part-of: --- src/compiler/glsl/glsl_parser_extras.cpp | 1 - src/compiler/glsl/ir_optimization.h | 1 - src/compiler/glsl/meson.build | 1 - src/compiler/glsl/opt_constant_propagation.cpp | 530 ------------------------- src/compiler/glsl/test_optpass.cpp | 2 - 5 files changed, 535 deletions(-) delete mode 100644 src/compiler/glsl/opt_constant_propagation.cpp diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp index aead74e..eb8e8a4 100644 --- a/src/compiler/glsl/glsl_parser_extras.cpp +++ b/src/compiler/glsl/glsl_parser_extras.cpp @@ -2398,7 +2398,6 @@ do_common_optimization(exec_list *ir, bool linked, OPT(do_dead_code_unlinked, ir); OPT(do_dead_code_local, ir); OPT(do_tree_grafting, ir); - OPT(do_constant_propagation, ir); if (linked) OPT(do_constant_variable, ir); else diff --git a/src/compiler/glsl/ir_optimization.h b/src/compiler/glsl/ir_optimization.h index 4a50d9f..5645036 100644 --- a/src/compiler/glsl/ir_optimization.h +++ b/src/compiler/glsl/ir_optimization.h @@ -49,7 +49,6 @@ bool do_algebraic(exec_list *instructions, bool native_integers, bool do_constant_folding(exec_list *instructions); bool do_constant_variable(exec_list *instructions); bool do_constant_variable_unlinked(exec_list *instructions); -bool do_constant_propagation(exec_list *instructions); bool do_dead_code(exec_list *instructions); bool do_dead_code_local(exec_list *instructions); bool do_dead_code_unlinked(exec_list *instructions); diff --git a/src/compiler/glsl/meson.build b/src/compiler/glsl/meson.build index 6035933..5f6fd26 100644 --- a/src/compiler/glsl/meson.build +++ b/src/compiler/glsl/meson.build @@ -215,7 +215,6 @@ files_libglsl = files( 'lower_vector_derefs.cpp', 'opt_algebraic.cpp', 'opt_constant_folding.cpp', - 'opt_constant_propagation.cpp', 'opt_constant_variable.cpp', 'opt_dead_builtin_variables.cpp', 'opt_dead_code.cpp', diff --git a/src/compiler/glsl/opt_constant_propagation.cpp b/src/compiler/glsl/opt_constant_propagation.cpp deleted file mode 100644 index 755b5ac..0000000 --- a/src/compiler/glsl/opt_constant_propagation.cpp +++ /dev/null @@ -1,530 +0,0 @@ -/* - * Copyright © 2010 Intel Corporation - * - * Permission is hereby granted, free of charge, to any person obtaining a - * constant of this software and associated documentation files (the "Software"), - * to deal in the Software without restriction, including without limitation - * the rights to use, constant, 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 constantright 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 CONSTANTRIGHT 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_constant_propagation.cpp - * - * Tracks assignments of constants to channels of variables, and - * usage of those constant channels with direct usage of the constants. - * - * This can lead to constant folding and algebraic optimizations in - * those later expressions, while causing no increase in instruction - * count (due to constants being generally free to load from a - * constant push buffer or as instruction immediate values) and - * possibly reducing register pressure. - */ - -#include "ir.h" -#include "ir_visitor.h" -#include "ir_rvalue_visitor.h" -#include "ir_basic_block.h" -#include "ir_optimization.h" -#include "compiler/glsl_types.h" -#include "util/hash_table.h" - -namespace { - -class acp_entry : public exec_node -{ -public: - /* override operator new from exec_node */ - DECLARE_LINEAR_ZALLOC_CXX_OPERATORS(acp_entry) - - acp_entry(ir_variable *var, unsigned write_mask, ir_constant *constant) - { - assert(var); - assert(constant); - this->var = var; - this->write_mask = write_mask; - this->constant = constant; - this->initial_values = write_mask; - } - - acp_entry(const acp_entry *src) - { - this->var = src->var; - this->write_mask = src->write_mask; - this->constant = src->constant; - this->initial_values = src->initial_values; - } - - ir_variable *var; - ir_constant *constant; - unsigned write_mask; - - /** Mask of values initially available in the constant. */ - unsigned initial_values; -}; - - -class ir_constant_propagation_visitor : public ir_rvalue_visitor { -public: - ir_constant_propagation_visitor() - { - progress = false; - killed_all = false; - mem_ctx = ralloc_context(0); - this->lin_ctx = linear_alloc_parent(this->mem_ctx, 0); - this->acp = new(mem_ctx) exec_list; - this->kills = _mesa_pointer_hash_table_create(mem_ctx); - } - ~ir_constant_propagation_visitor() - { - ralloc_free(mem_ctx); - } - - virtual ir_visitor_status visit_enter(class ir_loop *); - virtual ir_visitor_status visit_enter(class ir_function_signature *); - virtual ir_visitor_status visit_enter(class ir_function *); - virtual ir_visitor_status visit_leave(class ir_assignment *); - virtual ir_visitor_status visit_enter(class ir_call *); - virtual ir_visitor_status visit_enter(class ir_if *); - - void add_constant(ir_assignment *ir); - void constant_folding(ir_rvalue **rvalue); - void constant_propagation(ir_rvalue **rvalue); - void kill(ir_variable *ir, unsigned write_mask); - void handle_if_block(exec_list *instructions, hash_table *kills, bool *killed_all); - void handle_loop(class ir_loop *, bool keep_acp); - void handle_rvalue(ir_rvalue **rvalue); - - /** List of acp_entry: The available constants to propagate */ - exec_list *acp; - - /** - * Hash table of killed entries: maps variables to the mask of killed channels. - */ - hash_table *kills; - - bool progress; - - bool killed_all; - - void *mem_ctx; - void *lin_ctx; -}; - - -void -ir_constant_propagation_visitor::constant_folding(ir_rvalue **rvalue) -{ - if (this->in_assignee || *rvalue == NULL) - return; - - if (ir_constant_fold(rvalue)) - this->progress = true; - - ir_dereference_variable *var_ref = (*rvalue)->as_dereference_variable(); - if (var_ref && !var_ref->type->is_array()) { - ir_constant *constant = - var_ref->constant_expression_value(ralloc_parent(var_ref)); - if (constant) { - *rvalue = constant; - this->progress = true; - } - } -} - -void -ir_constant_propagation_visitor::constant_propagation(ir_rvalue **rvalue) { - - if (this->in_assignee || !*rvalue) - return; - - const glsl_type *type = (*rvalue)->type; - if (!type->is_scalar() && !type->is_vector()) - return; - - ir_swizzle *swiz = NULL; - ir_dereference_variable *deref = (*rvalue)->as_dereference_variable(); - if (!deref) { - swiz = (*rvalue)->as_swizzle(); - if (!swiz) - return; - - deref = swiz->val->as_dereference_variable(); - if (!deref) - return; - } - - ir_constant_data data; - memset(&data, 0, sizeof(data)); - - for (unsigned int i = 0; i < type->components(); i++) { - int channel; - acp_entry *found = NULL; - - if (swiz) { - switch (i) { - case 0: channel = swiz->mask.x; break; - case 1: channel = swiz->mask.y; break; - case 2: channel = swiz->mask.z; break; - case 3: channel = swiz->mask.w; break; - default: assert(!"shouldn't be reached"); channel = 0; break; - } - } else { - channel = i; - } - - foreach_in_list(acp_entry, entry, this->acp) { - if (entry->var == deref->var && entry->write_mask & (1 << channel)) { - found = entry; - break; - } - } - - if (!found) - return; - - int rhs_channel = 0; - for (int j = 0; j < 4; j++) { - if (j == channel) - break; - if (found->initial_values & (1 << j)) - rhs_channel++; - } - - switch (type->base_type) { - case GLSL_TYPE_FLOAT: - data.f[i] = found->constant->value.f[rhs_channel]; - break; - case GLSL_TYPE_FLOAT16: - data.f16[i] = found->constant->value.f16[rhs_channel]; - break; - case GLSL_TYPE_DOUBLE: - data.d[i] = found->constant->value.d[rhs_channel]; - break; - case GLSL_TYPE_INT: - data.i[i] = found->constant->value.i[rhs_channel]; - break; - case GLSL_TYPE_UINT: - data.u[i] = found->constant->value.u[rhs_channel]; - break; - case GLSL_TYPE_INT16: - data.i16[i] = found->constant->value.i16[rhs_channel]; - break; - case GLSL_TYPE_UINT16: - data.u16[i] = found->constant->value.u16[rhs_channel]; - break; - case GLSL_TYPE_BOOL: - data.b[i] = found->constant->value.b[rhs_channel]; - break; - case GLSL_TYPE_UINT64: - data.u64[i] = found->constant->value.u64[rhs_channel]; - break; - case GLSL_TYPE_INT64: - data.i64[i] = found->constant->value.i64[rhs_channel]; - break; - default: - assert(!"not reached"); - break; - } - } - - *rvalue = new(ralloc_parent(deref)) ir_constant(type, &data); - this->progress = true; -} - -void -ir_constant_propagation_visitor::handle_rvalue(ir_rvalue **rvalue) -{ - constant_propagation(rvalue); - constant_folding(rvalue); -} - -ir_visitor_status -ir_constant_propagation_visitor::visit_enter(ir_function_signature *ir) -{ - /* Treat entry into a function signature as a completely separate - * block. Any instructions at global scope will be shuffled into - * main() at link time, so they're irrelevant to us. - */ - exec_list *orig_acp = this->acp; - hash_table *orig_kills = this->kills; - bool orig_killed_all = this->killed_all; - - this->acp = new(mem_ctx) exec_list; - this->kills = _mesa_pointer_hash_table_create(mem_ctx); - this->killed_all = false; - - visit_list_elements(this, &ir->body); - - this->kills = orig_kills; - this->acp = orig_acp; - this->killed_all = orig_killed_all; - - return visit_continue_with_parent; -} - -ir_visitor_status -ir_constant_propagation_visitor::visit_leave(ir_assignment *ir) -{ - constant_folding(&ir->rhs); - - if (this->in_assignee) - return visit_continue; - - unsigned kill_mask = ir->write_mask; - if (ir->lhs->as_dereference_array()) { - /* The LHS of the assignment uses an array indexing operator (e.g. v[i] - * = ...;). Since we only try to constant propagate vectors and - * scalars, this means that either (a) array indexing is being used to - * select a vector component, or (b) the variable in question is neither - * a scalar or a vector, so we don't care about it. In the former case, - * we want to kill the whole vector, since in general we can't predict - * which vector component will be selected by array indexing. In the - * latter case, it doesn't matter what we do, so go ahead and kill the - * whole variable anyway. - * - * Note that if the array index is constant (e.g. v[2] = ...;), we could - * in principle be smarter, but we don't need to, because a future - * optimization pass will convert it to a simple assignment with the - * correct mask. - */ - kill_mask = ~0; - } - kill(ir->lhs->variable_referenced(), kill_mask); - - add_constant(ir); - - return visit_continue; -} - -ir_visitor_status -ir_constant_propagation_visitor::visit_enter(ir_function *ir) -{ - (void) ir; - return visit_continue; -} - -ir_visitor_status -ir_constant_propagation_visitor::visit_enter(ir_call *ir) -{ - /* Do constant propagation on call parameters, but skip any out params */ - foreach_two_lists(formal_node, &ir->callee->parameters, - actual_node, &ir->actual_parameters) { - ir_variable *sig_param = (ir_variable *) formal_node; - ir_rvalue *param = (ir_rvalue *) actual_node; - if (sig_param->data.mode != ir_var_function_out - && sig_param->data.mode != ir_var_function_inout) { - ir_rvalue *new_param = param; - handle_rvalue(&new_param); - if (new_param != param) - param->replace_with(new_param); - else - param->accept(this); - } - } - - /* Since we're unlinked, we don't (necssarily) know the side effects of - * this call. So kill all copies. - */ - acp->make_empty(); - this->killed_all = true; - - return visit_continue_with_parent; -} - -void -ir_constant_propagation_visitor::handle_if_block(exec_list *instructions, hash_table *kills, bool *killed_all) -{ - exec_list *orig_acp = this->acp; - hash_table *orig_kills = this->kills; - bool orig_killed_all = this->killed_all; - - this->acp = new(mem_ctx) exec_list; - this->kills = kills; - this->killed_all = false; - - /* Populate the initial acp with a constant of the original */ - foreach_in_list(acp_entry, a, orig_acp) { - this->acp->push_tail(new(this->lin_ctx) acp_entry(a)); - } - - visit_list_elements(this, instructions); - - *killed_all = this->killed_all; - this->kills = orig_kills; - this->acp = orig_acp; - this->killed_all = orig_killed_all; -} - -ir_visitor_status -ir_constant_propagation_visitor::visit_enter(ir_if *ir) -{ - ir->condition->accept(this); - handle_rvalue(&ir->condition); - - hash_table *new_kills = _mesa_pointer_hash_table_create(mem_ctx); - bool then_killed_all = false; - bool else_killed_all = false; - - handle_if_block(&ir->then_instructions, new_kills, &then_killed_all); - handle_if_block(&ir->else_instructions, new_kills, &else_killed_all); - - if (then_killed_all || else_killed_all) { - acp->make_empty(); - killed_all = true; - } else { - hash_table_foreach(new_kills, htk) - kill((ir_variable *) htk->key, (uintptr_t) htk->data); - } - - _mesa_hash_table_destroy(new_kills, NULL); - - /* handle_if_block() already descended into the children. */ - return visit_continue_with_parent; -} - -void -ir_constant_propagation_visitor::handle_loop(ir_loop *ir, bool keep_acp) -{ - exec_list *orig_acp = this->acp; - hash_table *orig_kills = this->kills; - bool orig_killed_all = this->killed_all; - - this->acp = new(mem_ctx) exec_list; - this->kills = _mesa_pointer_hash_table_create(mem_ctx); - this->killed_all = false; - - if (keep_acp) { - foreach_in_list(acp_entry, a, orig_acp) { - this->acp->push_tail(new(this->lin_ctx) acp_entry(a)); - } - } - - visit_list_elements(this, &ir->body_instructions); - - if (this->killed_all) { - orig_acp->make_empty(); - } - - hash_table *new_kills = this->kills; - this->kills = orig_kills; - this->acp = orig_acp; - this->killed_all = this->killed_all || orig_killed_all; - - hash_table_foreach(new_kills, htk) { - kill((ir_variable *) htk->key, (uintptr_t) htk->data); - } -} - -ir_visitor_status -ir_constant_propagation_visitor::visit_enter(ir_loop *ir) -{ - /* Make a conservative first pass over the loop with an empty ACP set. - * This also removes any killed entries from the original ACP set. - */ - handle_loop(ir, false); - - /* Then, run it again with the real ACP set, minus any killed entries. - * This takes care of propagating values from before the loop into it. - */ - handle_loop(ir, true); - - /* already descended into the children. */ - return visit_continue_with_parent; -} - -void -ir_constant_propagation_visitor::kill(ir_variable *var, unsigned write_mask) -{ - assert(var != NULL); - - /* We don't track non-vectors. */ - if (!var->type->is_vector() && !var->type->is_scalar()) - return; - - /* Remove any entries currently in the ACP for this kill. */ - foreach_in_list_safe(acp_entry, entry, this->acp) { - if (entry->var == var) { - entry->write_mask &= ~write_mask; - if (entry->write_mask == 0) - entry->remove(); - } - } - - /* Add this writemask of the variable to the hash table of killed - * variables in this block. - */ - hash_entry *kill_hash_entry = _mesa_hash_table_search(this->kills, var); - if (kill_hash_entry) { - uintptr_t new_write_mask = ((uintptr_t) kill_hash_entry->data) | write_mask; - kill_hash_entry->data = (void *) new_write_mask; - return; - } - /* Not already in the hash table. Make new entry. */ - _mesa_hash_table_insert(this->kills, var, (void *) uintptr_t(write_mask)); -} - -/** - * Adds an entry to the available constant list if it's a plain assignment - * of a variable to a variable. - */ -void -ir_constant_propagation_visitor::add_constant(ir_assignment *ir) -{ - acp_entry *entry; - - if (!ir->write_mask) - return; - - ir_dereference_variable *deref = ir->lhs->as_dereference_variable(); - ir_constant *constant = ir->rhs->as_constant(); - - if (!deref || !constant) - return; - - /* Only do constant propagation on vectors. Constant matrices, - * arrays, or structures would require more work elsewhere. - */ - if (!deref->var->type->is_vector() && !deref->var->type->is_scalar()) - return; - - /* We can't do copy propagation on buffer variables, since the underlying - * memory storage is shared across multiple threads we can't be sure that - * the variable value isn't modified between this assignment and the next - * instruction where its value is read. - */ - if (deref->var->data.mode == ir_var_shader_storage || - deref->var->data.mode == ir_var_shader_shared) - return; - - entry = new(this->lin_ctx) acp_entry(deref->var, ir->write_mask, constant); - this->acp->push_tail(entry); -} - -} /* unnamed namespace */ - -/** - * Does a constant propagation pass on the code present in the instruction stream. - */ -bool -do_constant_propagation(exec_list *instructions) -{ - ir_constant_propagation_visitor v; - - visit_list_elements(&v, instructions); - - return v.progress; -} diff --git a/src/compiler/glsl/test_optpass.cpp b/src/compiler/glsl/test_optpass.cpp index 2494d5a..7f8de6a 100644 --- a/src/compiler/glsl/test_optpass.cpp +++ b/src/compiler/glsl/test_optpass.cpp @@ -72,8 +72,6 @@ do_optimization(struct exec_list *ir, const char *optimization, return do_constant_variable(ir); } else if (strcmp(optimization, "do_constant_variable_unlinked") == 0) { return do_constant_variable_unlinked(ir); - } else if (strcmp(optimization, "do_constant_propagation") == 0) { - return do_constant_propagation(ir); } else if (strcmp(optimization, "do_dead_code") == 0) { return do_dead_code(ir); } else if (strcmp(optimization, "do_dead_code_local") == 0) { -- 2.7.4