Hi,
while reading bb-reorder code I noticed that it now may pick edge with
probability 0
as one preferred over edge with undefined probability. This is not quite
intended.
Also we never want to make the trace to go across abnormal/eh edge.
Bootstrapped/regtested x86_64-linux, will commit it shortly.
Honza
* bb-reorder.c (better_edge_p): Do not build traces across abnormal/eh
edges; zero probability is not better than uninitialized.
Index: bb-reorder.c
===================================================================
--- bb-reorder.c (revision 250021)
+++ bb-reorder.c (working copy)
@@ -957,7 +957,14 @@ better_edge_p (const_basic_block bb, con
return !cur_best_edge
|| cur_best_edge->dest->index > e->dest->index;
- if (prob > best_prob + diff_prob || !best_prob.initialized_p ())
+ /* Those edges are so expensive that continuing a trace is not useful
+ performance wise. */
+ if (e->flags & (EDGE_ABNORMAL | EDGE_EH))
+ return false;
+
+ if (prob > best_prob + diff_prob
+ || (!best_prob.initialized_p ()
+ && prob > profile_probability::guessed_never ()))
/* The edge has higher probability than the temporary best edge. */
is_better_edge = true;
else if (prob < best_prob - diff_prob)
