This patch fixes PR bootstrap/57154.
Bootstrapped on powerpc64-linux to ensure it fixes the bootstrap problem
reported
for that architecture, and also the test case attached to the bug report.
Also bootstrapped and regtested on x86_64-unknown-linux-gnu.
Ok for trunk?
Thanks,
Teresa
2013-05-03 Teresa Johnson <tejohn...@google.com>
PR bootstrap/57154
* sched-rgn.c (compute_dom_prob_ps): Ensure accumulated probabilities
do not exceed REG_BR_PROB_BASE.
Index: sched-rgn.c
===================================================================
--- sched-rgn.c (revision 198532)
+++ sched-rgn.c (working copy)
@@ -1442,6 +1442,12 @@ compute_dom_prob_ps (int bb)
bitmap_set_bit (pot_split[bb], EDGE_TO_BIT (out_edge));
prob[bb] += combine_probabilities (prob[pred_bb], in_edge->probability);
+ // The rounding divide in combine_probabilities can result in an extra
+ // probability increment propagating along 50-50 edges. Eventually when
+ // the edges re-merge, the accumulated probability can go slightly above
+ // REG_BR_PROB_BASE.
+ if (prob[bb] > REG_BR_PROB_BASE)
+ prob[bb] = REG_BR_PROB_BASE;
}
bitmap_set_bit (dom[bb], bb);
--
This patch is available for review at http://codereview.appspot.com/9179043
