------- Comment #14 from bonzini at gnu dot org 2009-02-05 13:02 -------
20% of PRE time is spent in qsort via sorted_array_from_bitmap_set. Rewriting
it like this makes it a bit faster (it shaves 12% more of PRE time):
FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
{
/* The number of expressions having a given value is usually
relatively small. Thus, rather than making a vector of all the
expressions and sorting it by value id, we walk the values and
check in the reverse mapping that tells us what expressions have
a given value, to filter those in our set. If this is somehow
a significant lose for some cases, we can choose which set to
walk based on the set size. */
bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
{
if (bitmap_bit_p (set->expressions, j))
VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
}
}
I'll add this to the bootstrap/regtest.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35639
