[Bug lto/54312] New: uniquify_nodes takes 12% of Mozilla LTO build
hubicka at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Sat Aug 18 09:47:00 GMT 2012
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54312
Bug #: 54312
Summary: uniquify_nodes takes 12% of Mozilla LTO build
Classification: Unclassified
Product: gcc
Version: lto
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: hubicka@gcc.gnu.org
uniquify_nodes has quadratic loop removing types from variant lists:
/* Remove us from our main variant list if we are not the
variant leader. */
if (TYPE_MAIN_VARIANT (t) != t)
{
tem = TYPE_MAIN_VARIANT (t);
while (tem && TYPE_NEXT_VARIANT (tem) != t)
tem = TYPE_NEXT_VARIANT (tem);
if (tem)
TYPE_NEXT_VARIANT (tem) = TYPE_NEXT_VARIANT (t);
TYPE_NEXT_VARIANT (t) = NULL_TREE;
}
this consume a lot of time building Mozilla (and was introduced by Michael's
patch cleaning up the stream in process). Can't we do a bit better here?
(this was introduced in 4.7)
Honza
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