- add comment explaining the connection betwenn the race and Follower -> Leader trans...

[r22963]

diff --git a/ir/opt/combo.c b/ir/opt/combo.c
index 9d4584e..1701b58 100644 (file)
--- a/ir/opt/combo.c
+++ b/ir/opt/combo.c
@@ -1132,6 +1132,20 @@ static partition_t *split(partition_t **pX, node_t *gg, environment_t *env) {
        senv[1].index     = 0;
        senv[1].side      = 2;
 
+       /*
+        * Some informations on the race that are not stated clearly in Click's
+        * thesis.
+        * 1) A follower stays on the side that reach him first.
+        * 2) If the other side reches a follower, if will be converted to
+        *    a leader. /This must be done after the race is over, else the
+        *    edges we are iterating on are renumbered./
+        * 3) /New leader might end up on both sides./
+        * 4) /If one side ends up with new Leaders, we must ensure that
+        *    they can split out by opcode, hence we have to put _every_
+        *    partition with new Leader nodes on the cprop list, as
+        *    opcode splitting is done by split_by() at the end of
+        *    constant propagation./
+        */
        for (;;) {
                if (step(&senv[0])) {
                        winner = 0;