diff options
Diffstat (limited to 'mesalib/src/mesa/program/register_allocate.c')
| -rw-r--r-- | mesalib/src/mesa/program/register_allocate.c | 913 |
1 files changed, 455 insertions, 458 deletions
diff --git a/mesalib/src/mesa/program/register_allocate.c b/mesalib/src/mesa/program/register_allocate.c index 8992b91b6..95a9bde40 100644 --- a/mesalib/src/mesa/program/register_allocate.c +++ b/mesalib/src/mesa/program/register_allocate.c @@ -1,458 +1,455 @@ -/*
- * 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 <eric@anholt.net>
- *
- */
-
-/** @file register_allocate.c
- *
- * Graph-coloring register allocator.
- */
-
-#include <talloc.h>
-
-#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;
-}
+/* + * 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 <eric@anholt.net> + * + */ + +/** @file register_allocate.c + * + * Graph-coloring register allocator. + */ + +#include <ralloc.h> + +#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 = rzalloc(NULL, struct ra_regs); + regs->count = count; + regs->regs = rzalloc_array(regs, struct ra_reg, count); + + for (i = 0; i < count; i++) { + regs->regs[i].conflicts = rzalloc_array(regs->regs, GLboolean, count); + regs->regs[i].conflicts[i] = GL_TRUE; + + regs->regs[i].conflict_list = ralloc_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 = reralloc(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 = reralloc(regs->regs, regs->classes, struct ra_class *, + regs->class_count + 1); + + class = rzalloc(regs, struct ra_class); + regs->classes[regs->class_count] = class; + + class->regs = rzalloc_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 = ralloc_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 = rzalloc(regs, struct ra_graph); + g->regs = regs; + g->nodes = rzalloc_array(g, struct ra_node, count); + g->count = count; + + g->stack = rzalloc_array(g, unsigned int, count); + + for (i = 0; i < count; i++) { + g->nodes[i].adjacency = rzalloc_array(g, GLboolean, count); + g->nodes[i].adjacency_list = ralloc_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; +} |