From: Archit Shah <archit@cave32.com>
Date: Wed, 28 Oct 2020 05:35:26 +0000 (+0000)
Subject: [optimizer] Recompute dominators if and/or_pullup succeeds
X-Git-Url: https://git.tcpdump.org/libpcap/commitdiff_plain/ae7216eb6094534d2a3a739d8867feb33a9fd25e

[optimizer] Recompute dominators if and/or_pullup succeeds
---

diff --git a/optimize.c b/optimize.c
index a7cff960..4115cb55 100644
--- a/optimize.c
+++ b/optimize.c
@@ -1801,7 +1801,7 @@ opt_j(opt_state_t *opt_state, struct edge *ep)
  *
  */
 static void
-or_pullup(opt_state_t *opt_state, struct block *b)
+or_pullup(opt_state_t *opt_state, struct block *b, struct block *root)
 {
 	bpf_u_int32 val;
 	int at_top;
@@ -1962,10 +1962,15 @@ or_pullup(opt_state_t *opt_state, struct block *b)
 	 * optimizer gets into one of those infinite loops.
 	 */
 	opt_state->done = 0;
+
+	/*
+	 * Recompute dominator sets as control flow graph has changed.
+	 */
+	find_dom(opt_state, root);
 }
 
 static void
-and_pullup(opt_state_t *opt_state, struct block *b)
+and_pullup(opt_state_t *opt_state, struct block *b, struct block *root)
 {
 	bpf_u_int32 val;
 	int at_top;
@@ -2058,6 +2063,11 @@ and_pullup(opt_state_t *opt_state, struct block *b)
 	 * optimizer gets into one of those infinite loops.
 	 */
 	opt_state->done = 0;
+
+	/*
+	 * Recompute dominator sets as control flow graph has changed.
+	 */
+	find_dom(opt_state, root);
 }
 
 static void
@@ -2104,8 +2114,8 @@ opt_blks(opt_state_t *opt_state, struct icode *ic, int do_stmts)
 	find_inedges(opt_state, ic->root);
 	for (i = 1; i <= maxlevel; ++i) {
 		for (p = opt_state->levels[i]; p; p = p->link) {
-			or_pullup(opt_state, p);
-			and_pullup(opt_state, p);
+			or_pullup(opt_state, p, ic->root);
+			and_pullup(opt_state, p, ic->root);
 		}
 	}
 }