https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89150
Bug ID: 89150
Summary: [9 regression] Tree form bitmaps break GC
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: nathan at gcc dot gnu.org
Target Milestone: ---
bitmap_element is marked as a doubly linked list.
struct GTY((chain_next ("%h.next"), chain_prev ("%h.prev"))) bitmap_element {
That is untrue for tree-form bitmaps and breaks the GC marker.
The fix is more complicated than marking as a singly linked list (that presumes
you start at the beginning of the list) Sadly I think the gty generator may
need tweaking. or we could remove both chain markers.
