From b8ffa56f8bda74a402eae0c89aadfda7b7db507f Mon Sep 17 00:00:00 2001 From: marha Date: Sat, 22 Jan 2011 13:05:58 +0000 Subject: mesalib git update 22/1/2011 --- mesalib/src/mesa/program/register_allocate.c | 916 +++++++++++++-------------- 1 file changed, 458 insertions(+), 458 deletions(-) (limited to 'mesalib/src/mesa/program') diff --git a/mesalib/src/mesa/program/register_allocate.c b/mesalib/src/mesa/program/register_allocate.c index f984e2f14..8992b91b6 100644 --- a/mesalib/src/mesa/program/register_allocate.c +++ b/mesalib/src/mesa/program/register_allocate.c @@ -1,458 +1,458 @@ -/* - * 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. - * - * Authors: - * Eric Anholt - * - */ - -/** @file register_allocate.c - * - * Graph-coloring register allocator. - */ - -#include - -#include "main/imports.h" -#include "main/macros.h" -#include "main/mtypes.h" -#include "register_allocate.h" - -struct ra_reg { - GLboolean *conflicts; - unsigned int *conflict_list; - unsigned int conflict_list_size; - unsigned int num_conflicts; -}; - -struct ra_regs { - struct ra_reg *regs; - unsigned int count; - - struct ra_class **classes; - unsigned int class_count; -}; - -struct ra_class { - GLboolean *regs; - - /** - * p_B in Runeson/Nyström paper. - * - * This is "how many regs are in the set." - */ - unsigned int p; - - /** - * q_B,C in Runeson/Nyström paper. - */ - unsigned int *q; -}; - -struct ra_node { - GLboolean *adjacency; - unsigned int *adjacency_list; - unsigned int class; - unsigned int adjacency_count; - unsigned int reg; - GLboolean in_stack; - float spill_cost; -}; - -struct ra_graph { - struct ra_regs *regs; - /** - * the variables that need register allocation. - */ - struct ra_node *nodes; - unsigned int count; /**< count of nodes. */ - - unsigned int *stack; - unsigned int stack_count; -}; - -struct ra_regs * -ra_alloc_reg_set(unsigned int count) -{ - unsigned int i; - struct ra_regs *regs; - - regs = talloc_zero(NULL, struct ra_regs); - regs->count = count; - regs->regs = talloc_zero_array(regs, struct ra_reg, count); - - for (i = 0; i < count; i++) { - regs->regs[i].conflicts = talloc_zero_array(regs->regs, GLboolean, count); - regs->regs[i].conflicts[i] = GL_TRUE; - - regs->regs[i].conflict_list = talloc_array(regs->regs, unsigned int, 4); - regs->regs[i].conflict_list_size = 4; - regs->regs[i].conflict_list[0] = i; - regs->regs[i].num_conflicts = 1; - } - - return regs; -} - -static void -ra_add_conflict_list(struct ra_regs *regs, unsigned int r1, unsigned int r2) -{ - struct ra_reg *reg1 = ®s->regs[r1]; - - if (reg1->conflict_list_size == reg1->num_conflicts) { - reg1->conflict_list_size *= 2; - reg1->conflict_list = talloc_realloc(regs, - reg1->conflict_list, - unsigned int, - reg1->conflict_list_size); - } - reg1->conflict_list[reg1->num_conflicts++] = r2; - reg1->conflicts[r2] = GL_TRUE; -} - -void -ra_add_reg_conflict(struct ra_regs *regs, unsigned int r1, unsigned int r2) -{ - if (!regs->regs[r1].conflicts[r2]) { - ra_add_conflict_list(regs, r1, r2); - ra_add_conflict_list(regs, r2, r1); - } -} - -unsigned int -ra_alloc_reg_class(struct ra_regs *regs) -{ - struct ra_class *class; - - regs->classes = talloc_realloc(regs, regs->classes, - struct ra_class *, - regs->class_count + 1); - - class = talloc_zero(regs, struct ra_class); - regs->classes[regs->class_count] = class; - - class->regs = talloc_zero_array(class, GLboolean, regs->count); - - return regs->class_count++; -} - -void -ra_class_add_reg(struct ra_regs *regs, unsigned int c, unsigned int r) -{ - struct ra_class *class = regs->classes[c]; - - class->regs[r] = GL_TRUE; - class->p++; -} - -/** - * Must be called after all conflicts and register classes have been - * set up and before the register set is used for allocation. - */ -void -ra_set_finalize(struct ra_regs *regs) -{ - unsigned int b, c; - - for (b = 0; b < regs->class_count; b++) { - regs->classes[b]->q = talloc_array(regs, unsigned int, regs->class_count); - } - - /* Compute, for each class B and C, how many regs of B an - * allocation to C could conflict with. - */ - for (b = 0; b < regs->class_count; b++) { - for (c = 0; c < regs->class_count; c++) { - unsigned int rc; - int max_conflicts = 0; - - for (rc = 0; rc < regs->count; rc++) { - int conflicts = 0; - int i; - - if (!regs->classes[c]->regs[rc]) - continue; - - for (i = 0; i < regs->regs[rc].num_conflicts; i++) { - unsigned int rb = regs->regs[rc].conflict_list[i]; - if (regs->classes[b]->regs[rb]) - conflicts++; - } - max_conflicts = MAX2(max_conflicts, conflicts); - } - regs->classes[b]->q[c] = max_conflicts; - } - } -} - -static void -ra_add_node_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2) -{ - g->nodes[n1].adjacency[n2] = GL_TRUE; - g->nodes[n1].adjacency_list[g->nodes[n1].adjacency_count] = n2; - g->nodes[n1].adjacency_count++; -} - -struct ra_graph * -ra_alloc_interference_graph(struct ra_regs *regs, unsigned int count) -{ - struct ra_graph *g; - unsigned int i; - - g = talloc_zero(regs, struct ra_graph); - g->regs = regs; - g->nodes = talloc_zero_array(g, struct ra_node, count); - g->count = count; - - g->stack = talloc_zero_array(g, unsigned int, count); - - for (i = 0; i < count; i++) { - g->nodes[i].adjacency = talloc_zero_array(g, GLboolean, count); - g->nodes[i].adjacency_list = talloc_array(g, unsigned int, count); - g->nodes[i].adjacency_count = 0; - ra_add_node_adjacency(g, i, i); - g->nodes[i].reg = ~0; - } - - return g; -} - -void -ra_set_node_class(struct ra_graph *g, - unsigned int n, unsigned int class) -{ - g->nodes[n].class = class; -} - -void -ra_add_node_interference(struct ra_graph *g, - unsigned int n1, unsigned int n2) -{ - if (!g->nodes[n1].adjacency[n2]) { - ra_add_node_adjacency(g, n1, n2); - ra_add_node_adjacency(g, n2, n1); - } -} - -static GLboolean pq_test(struct ra_graph *g, unsigned int n) -{ - unsigned int j; - unsigned int q = 0; - int n_class = g->nodes[n].class; - - for (j = 0; j < g->nodes[n].adjacency_count; j++) { - unsigned int n2 = g->nodes[n].adjacency_list[j]; - unsigned int n2_class = g->nodes[n2].class; - - if (n != n2 && !g->nodes[n2].in_stack) { - q += g->regs->classes[n_class]->q[n2_class]; - } - } - - return q < g->regs->classes[n_class]->p; -} - -/** - * Simplifies the interference graph by pushing all - * trivially-colorable nodes into a stack of nodes to be colored, - * removing them from the graph, and rinsing and repeating. - * - * Returns GL_TRUE if all nodes were removed from the graph. GL_FALSE - * means that either spilling will be required, or optimistic coloring - * should be applied. - */ -GLboolean -ra_simplify(struct ra_graph *g) -{ - GLboolean progress = GL_TRUE; - int i; - - while (progress) { - progress = GL_FALSE; - - for (i = g->count - 1; i >= 0; i--) { - if (g->nodes[i].in_stack) - continue; - - if (pq_test(g, i)) { - g->stack[g->stack_count] = i; - g->stack_count++; - g->nodes[i].in_stack = GL_TRUE; - progress = GL_TRUE; - } - } - } - - for (i = 0; i < g->count; i++) { - if (!g->nodes[i].in_stack) - return GL_FALSE; - } - - return GL_TRUE; -} - -/** - * Pops nodes from the stack back into the graph, coloring them with - * registers as they go. - * - * If all nodes were trivially colorable, then this must succeed. If - * not (optimistic coloring), then it may return GL_FALSE; - */ -GLboolean -ra_select(struct ra_graph *g) -{ - int i; - - while (g->stack_count != 0) { - unsigned int r; - int n = g->stack[g->stack_count - 1]; - struct ra_class *c = g->regs->classes[g->nodes[n].class]; - - /* Find the lowest-numbered reg which is not used by a member - * of the graph adjacent to us. - */ - for (r = 0; r < g->regs->count; r++) { - if (!c->regs[r]) - continue; - - /* Check if any of our neighbors conflict with this register choice. */ - for (i = 0; i < g->nodes[n].adjacency_count; i++) { - unsigned int n2 = g->nodes[n].adjacency_list[i]; - - if (!g->nodes[n2].in_stack && - g->regs->regs[r].conflicts[g->nodes[n2].reg]) { - break; - } - } - if (i == g->nodes[n].adjacency_count) - break; - } - if (r == g->regs->count) - return GL_FALSE; - - g->nodes[n].reg = r; - g->nodes[n].in_stack = GL_FALSE; - g->stack_count--; - } - - return GL_TRUE; -} - -/** - * Optimistic register coloring: Just push the remaining nodes - * on the stack. They'll be colored first in ra_select(), and - * if they succeed then the locally-colorable nodes are still - * locally-colorable and the rest of the register allocation - * will succeed. - */ -void -ra_optimistic_color(struct ra_graph *g) -{ - unsigned int i; - - for (i = 0; i < g->count; i++) { - if (g->nodes[i].in_stack) - continue; - - g->stack[g->stack_count] = i; - g->stack_count++; - g->nodes[i].in_stack = GL_TRUE; - } -} - -GLboolean -ra_allocate_no_spills(struct ra_graph *g) -{ - if (!ra_simplify(g)) { - ra_optimistic_color(g); - } - return ra_select(g); -} - -unsigned int -ra_get_node_reg(struct ra_graph *g, unsigned int n) -{ - return g->nodes[n].reg; -} - -static float -ra_get_spill_benefit(struct ra_graph *g, unsigned int n) -{ - int j; - float benefit = 0; - int n_class = g->nodes[n].class; - - /* Define the benefit of eliminating an interference between n, n2 - * through spilling as q(C, B) / p(C). This is similar to the - * "count number of edges" approach of traditional graph coloring, - * but takes classes into account. - */ - for (j = 0; j < g->nodes[n].adjacency_count; j++) { - unsigned int n2 = g->nodes[n].adjacency_list[j]; - if (n != n2) { - unsigned int n2_class = g->nodes[n2].class; - benefit += ((float)g->regs->classes[n_class]->q[n2_class] / - g->regs->classes[n_class]->p); - } - } - - return benefit; -} - -/** - * Returns a node number to be spilled according to the cost/benefit using - * the pq test, or -1 if there are no spillable nodes. - */ -int -ra_get_best_spill_node(struct ra_graph *g) -{ - unsigned int best_node = -1; - unsigned int best_benefit = 0.0; - unsigned int n; - - for (n = 0; n < g->count; n++) { - float cost = g->nodes[n].spill_cost; - float benefit; - - if (cost <= 0.0) - continue; - - benefit = ra_get_spill_benefit(g, n); - - if (benefit / cost > best_benefit) { - best_benefit = benefit / cost; - best_node = n; - } - } - - return best_node; -} - -/** - * Only nodes with a spill cost set (cost != 0.0) will be considered - * for register spilling. - */ -void -ra_set_node_spill_cost(struct ra_graph *g, unsigned int n, float cost) -{ - g->nodes[n].spill_cost = cost; -} +/* + * 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. + * + * Authors: + * Eric Anholt + * + */ + +/** @file register_allocate.c + * + * Graph-coloring register allocator. + */ + +#include + +#include "main/imports.h" +#include "main/macros.h" +#include "main/mtypes.h" +#include "register_allocate.h" + +struct ra_reg { + GLboolean *conflicts; + unsigned int *conflict_list; + unsigned int conflict_list_size; + unsigned int num_conflicts; +}; + +struct ra_regs { + struct ra_reg *regs; + unsigned int count; + + struct ra_class **classes; + unsigned int class_count; +}; + +struct ra_class { + GLboolean *regs; + + /** + * p_B in Runeson/Nyström paper. + * + * This is "how many regs are in the set." + */ + unsigned int p; + + /** + * q_B,C in Runeson/Nyström paper. + */ + unsigned int *q; +}; + +struct ra_node { + GLboolean *adjacency; + unsigned int *adjacency_list; + unsigned int class; + unsigned int adjacency_count; + unsigned int reg; + GLboolean in_stack; + float spill_cost; +}; + +struct ra_graph { + struct ra_regs *regs; + /** + * the variables that need register allocation. + */ + struct ra_node *nodes; + unsigned int count; /**< count of nodes. */ + + unsigned int *stack; + unsigned int stack_count; +}; + +struct ra_regs * +ra_alloc_reg_set(unsigned int count) +{ + unsigned int i; + struct ra_regs *regs; + + regs = talloc_zero(NULL, struct ra_regs); + regs->count = count; + regs->regs = talloc_zero_array(regs, struct ra_reg, count); + + for (i = 0; i < count; i++) { + regs->regs[i].conflicts = talloc_zero_array(regs->regs, GLboolean, count); + regs->regs[i].conflicts[i] = GL_TRUE; + + regs->regs[i].conflict_list = talloc_array(regs->regs, unsigned int, 4); + regs->regs[i].conflict_list_size = 4; + regs->regs[i].conflict_list[0] = i; + regs->regs[i].num_conflicts = 1; + } + + return regs; +} + +static void +ra_add_conflict_list(struct ra_regs *regs, unsigned int r1, unsigned int r2) +{ + struct ra_reg *reg1 = ®s->regs[r1]; + + if (reg1->conflict_list_size == reg1->num_conflicts) { + reg1->conflict_list_size *= 2; + reg1->conflict_list = talloc_realloc(regs->regs, + reg1->conflict_list, + unsigned int, + reg1->conflict_list_size); + } + reg1->conflict_list[reg1->num_conflicts++] = r2; + reg1->conflicts[r2] = GL_TRUE; +} + +void +ra_add_reg_conflict(struct ra_regs *regs, unsigned int r1, unsigned int r2) +{ + if (!regs->regs[r1].conflicts[r2]) { + ra_add_conflict_list(regs, r1, r2); + ra_add_conflict_list(regs, r2, r1); + } +} + +unsigned int +ra_alloc_reg_class(struct ra_regs *regs) +{ + struct ra_class *class; + + regs->classes = talloc_realloc(regs->regs, regs->classes, + struct ra_class *, + regs->class_count + 1); + + class = talloc_zero(regs, struct ra_class); + regs->classes[regs->class_count] = class; + + class->regs = talloc_zero_array(class, GLboolean, regs->count); + + return regs->class_count++; +} + +void +ra_class_add_reg(struct ra_regs *regs, unsigned int c, unsigned int r) +{ + struct ra_class *class = regs->classes[c]; + + class->regs[r] = GL_TRUE; + class->p++; +} + +/** + * Must be called after all conflicts and register classes have been + * set up and before the register set is used for allocation. + */ +void +ra_set_finalize(struct ra_regs *regs) +{ + unsigned int b, c; + + for (b = 0; b < regs->class_count; b++) { + regs->classes[b]->q = talloc_array(regs, unsigned int, regs->class_count); + } + + /* Compute, for each class B and C, how many regs of B an + * allocation to C could conflict with. + */ + for (b = 0; b < regs->class_count; b++) { + for (c = 0; c < regs->class_count; c++) { + unsigned int rc; + int max_conflicts = 0; + + for (rc = 0; rc < regs->count; rc++) { + int conflicts = 0; + int i; + + if (!regs->classes[c]->regs[rc]) + continue; + + for (i = 0; i < regs->regs[rc].num_conflicts; i++) { + unsigned int rb = regs->regs[rc].conflict_list[i]; + if (regs->classes[b]->regs[rb]) + conflicts++; + } + max_conflicts = MAX2(max_conflicts, conflicts); + } + regs->classes[b]->q[c] = max_conflicts; + } + } +} + +static void +ra_add_node_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2) +{ + g->nodes[n1].adjacency[n2] = GL_TRUE; + g->nodes[n1].adjacency_list[g->nodes[n1].adjacency_count] = n2; + g->nodes[n1].adjacency_count++; +} + +struct ra_graph * +ra_alloc_interference_graph(struct ra_regs *regs, unsigned int count) +{ + struct ra_graph *g; + unsigned int i; + + g = talloc_zero(regs, struct ra_graph); + g->regs = regs; + g->nodes = talloc_zero_array(g, struct ra_node, count); + g->count = count; + + g->stack = talloc_zero_array(g, unsigned int, count); + + for (i = 0; i < count; i++) { + g->nodes[i].adjacency = talloc_zero_array(g, GLboolean, count); + g->nodes[i].adjacency_list = talloc_array(g, unsigned int, count); + g->nodes[i].adjacency_count = 0; + ra_add_node_adjacency(g, i, i); + g->nodes[i].reg = ~0; + } + + return g; +} + +void +ra_set_node_class(struct ra_graph *g, + unsigned int n, unsigned int class) +{ + g->nodes[n].class = class; +} + +void +ra_add_node_interference(struct ra_graph *g, + unsigned int n1, unsigned int n2) +{ + if (!g->nodes[n1].adjacency[n2]) { + ra_add_node_adjacency(g, n1, n2); + ra_add_node_adjacency(g, n2, n1); + } +} + +static GLboolean pq_test(struct ra_graph *g, unsigned int n) +{ + unsigned int j; + unsigned int q = 0; + int n_class = g->nodes[n].class; + + for (j = 0; j < g->nodes[n].adjacency_count; j++) { + unsigned int n2 = g->nodes[n].adjacency_list[j]; + unsigned int n2_class = g->nodes[n2].class; + + if (n != n2 && !g->nodes[n2].in_stack) { + q += g->regs->classes[n_class]->q[n2_class]; + } + } + + return q < g->regs->classes[n_class]->p; +} + +/** + * Simplifies the interference graph by pushing all + * trivially-colorable nodes into a stack of nodes to be colored, + * removing them from the graph, and rinsing and repeating. + * + * Returns GL_TRUE if all nodes were removed from the graph. GL_FALSE + * means that either spilling will be required, or optimistic coloring + * should be applied. + */ +GLboolean +ra_simplify(struct ra_graph *g) +{ + GLboolean progress = GL_TRUE; + int i; + + while (progress) { + progress = GL_FALSE; + + for (i = g->count - 1; i >= 0; i--) { + if (g->nodes[i].in_stack) + continue; + + if (pq_test(g, i)) { + g->stack[g->stack_count] = i; + g->stack_count++; + g->nodes[i].in_stack = GL_TRUE; + progress = GL_TRUE; + } + } + } + + for (i = 0; i < g->count; i++) { + if (!g->nodes[i].in_stack) + return GL_FALSE; + } + + return GL_TRUE; +} + +/** + * Pops nodes from the stack back into the graph, coloring them with + * registers as they go. + * + * If all nodes were trivially colorable, then this must succeed. If + * not (optimistic coloring), then it may return GL_FALSE; + */ +GLboolean +ra_select(struct ra_graph *g) +{ + int i; + + while (g->stack_count != 0) { + unsigned int r; + int n = g->stack[g->stack_count - 1]; + struct ra_class *c = g->regs->classes[g->nodes[n].class]; + + /* Find the lowest-numbered reg which is not used by a member + * of the graph adjacent to us. + */ + for (r = 0; r < g->regs->count; r++) { + if (!c->regs[r]) + continue; + + /* Check if any of our neighbors conflict with this register choice. */ + for (i = 0; i < g->nodes[n].adjacency_count; i++) { + unsigned int n2 = g->nodes[n].adjacency_list[i]; + + if (!g->nodes[n2].in_stack && + g->regs->regs[r].conflicts[g->nodes[n2].reg]) { + break; + } + } + if (i == g->nodes[n].adjacency_count) + break; + } + if (r == g->regs->count) + return GL_FALSE; + + g->nodes[n].reg = r; + g->nodes[n].in_stack = GL_FALSE; + g->stack_count--; + } + + return GL_TRUE; +} + +/** + * Optimistic register coloring: Just push the remaining nodes + * on the stack. They'll be colored first in ra_select(), and + * if they succeed then the locally-colorable nodes are still + * locally-colorable and the rest of the register allocation + * will succeed. + */ +void +ra_optimistic_color(struct ra_graph *g) +{ + unsigned int i; + + for (i = 0; i < g->count; i++) { + if (g->nodes[i].in_stack) + continue; + + g->stack[g->stack_count] = i; + g->stack_count++; + g->nodes[i].in_stack = GL_TRUE; + } +} + +GLboolean +ra_allocate_no_spills(struct ra_graph *g) +{ + if (!ra_simplify(g)) { + ra_optimistic_color(g); + } + return ra_select(g); +} + +unsigned int +ra_get_node_reg(struct ra_graph *g, unsigned int n) +{ + return g->nodes[n].reg; +} + +static float +ra_get_spill_benefit(struct ra_graph *g, unsigned int n) +{ + int j; + float benefit = 0; + int n_class = g->nodes[n].class; + + /* Define the benefit of eliminating an interference between n, n2 + * through spilling as q(C, B) / p(C). This is similar to the + * "count number of edges" approach of traditional graph coloring, + * but takes classes into account. + */ + for (j = 0; j < g->nodes[n].adjacency_count; j++) { + unsigned int n2 = g->nodes[n].adjacency_list[j]; + if (n != n2) { + unsigned int n2_class = g->nodes[n2].class; + benefit += ((float)g->regs->classes[n_class]->q[n2_class] / + g->regs->classes[n_class]->p); + } + } + + return benefit; +} + +/** + * Returns a node number to be spilled according to the cost/benefit using + * the pq test, or -1 if there are no spillable nodes. + */ +int +ra_get_best_spill_node(struct ra_graph *g) +{ + unsigned int best_node = -1; + unsigned int best_benefit = 0.0; + unsigned int n; + + for (n = 0; n < g->count; n++) { + float cost = g->nodes[n].spill_cost; + float benefit; + + if (cost <= 0.0) + continue; + + benefit = ra_get_spill_benefit(g, n); + + if (benefit / cost > best_benefit) { + best_benefit = benefit / cost; + best_node = n; + } + } + + return best_node; +} + +/** + * Only nodes with a spill cost set (cost != 0.0) will be considered + * for register spilling. + */ +void +ra_set_node_spill_cost(struct ra_graph *g, unsigned int n, float cost) +{ + g->nodes[n].spill_cost = cost; +} -- cgit v1.2.3