From 9040215f5d2894e9a900b0f4b154c617f9a0db27 Mon Sep 17 00:00:00 2001
From: Jason Ekstrand <jason@jlekstrand.net>
Date: Tue, 7 May 2019 17:16:58 -0500
Subject: [PATCH] util/ra: Add a helper for resetting a node's interference

Reviewed-by: Eric Anholt <eric@anholt.net>
---
 src/util/register_allocate.c | 36 ++++++++++++++++++++++++++++++++++++
 src/util/register_allocate.h |  1 +
 2 files changed, 37 insertions(+)

diff --git a/src/util/register_allocate.c b/src/util/register_allocate.c
index 8c10741..e1138c6 100644
--- a/src/util/register_allocate.c
+++ b/src/util/register_allocate.c
@@ -426,6 +426,31 @@ ra_add_node_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2)
 }
 
 static void
+ra_node_remove_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2)
+{
+   BITSET_CLEAR(g->nodes[n1].adjacency, n2);
+
+   assert(n1 != n2);
+
+   int n1_class = g->nodes[n1].class;
+   int n2_class = g->nodes[n2].class;
+   g->nodes[n1].q_total -= g->regs->classes[n1_class]->q[n2_class];
+
+   unsigned int i;
+   for (i = 0; i < g->nodes[n1].adjacency_count; i++) {
+      if (g->nodes[n1].adjacency_list[i] == n2) {
+         memmove(&g->nodes[n1].adjacency_list[i],
+                 &g->nodes[n1].adjacency_list[i + 1],
+                 (g->nodes[n1].adjacency_count - i - 1) *
+                 sizeof(g->nodes[n1].adjacency_list[0]));
+         break;
+      }
+   }
+   assert(i < g->nodes[n1].adjacency_count);
+   g->nodes[n1].adjacency_count--;
+}
+
+static void
 ra_realloc_interference_graph(struct ra_graph *g, unsigned int alloc)
 {
    if (alloc <= g->alloc)
@@ -536,6 +561,17 @@ ra_add_node_interference(struct ra_graph *g,
    }
 }
 
+void
+ra_reset_node_interference(struct ra_graph *g, unsigned int n)
+{
+   for (unsigned int i = 0; i < g->nodes[n].adjacency_count; i++)
+      ra_node_remove_adjacency(g, g->nodes[n].adjacency_list[i], n);
+
+   memset(g->nodes[n].adjacency, 0,
+          BITSET_WORDS(g->count) * sizeof(BITSET_WORD));
+   g->nodes[n].adjacency_count = 0;
+}
+
 static void
 update_pq_info(struct ra_graph *g, unsigned int n)
 {
diff --git a/src/util/register_allocate.h b/src/util/register_allocate.h
index 834503e..168c6e3 100644
--- a/src/util/register_allocate.h
+++ b/src/util/register_allocate.h
@@ -84,6 +84,7 @@ void ra_set_select_reg_callback(struct ra_graph *g,
                                 void *data);
 void ra_add_node_interference(struct ra_graph *g,
                               unsigned int n1, unsigned int n2);
+void ra_reset_node_interference(struct ra_graph *g, unsigned int n);
 /** @} */
 
 /** @{ Graph-coloring register allocation */
-- 
2.7.4