[Bug c++/70617] internal compiler error: Segmentation fault

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70617

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
(gdb) p p
$2 = (const void *) 0x1f0

is the TREE_TYPE of a CEIL_MOD_EXPR.  That looks like a bogus pointer to me.
That CEIL_MOD_EXPR is at 0x7ffff5bd0b48.  It's first allocated as TYPE_DECL
for me, then as lang-specific via cxx_make_type for a UNION_TYPE
(0x7ffff5bd2150).

We end up coming here via walking CP binding levels

 TYPE_NAME (TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (TYPE_CANONICAL (TREE_TYPE
(FUNCTION_DECL))))))

and then that TYPE_NAME is CEIL_MOD_EXPR.

bool <Tab14> (struct tVfpPacketDesc *, unsigned char, const struct
VFP_INGRESS_PORT_RECORD *, unsigned int, struct t_ing_zeroed *, unsigned int *,
unsigned int *, unsigned int *, const struct INTERFACE_DEST_INFO * *, union
IP_ADDRESS_AND_L2TP *, struct t_ing_p1_flags *, union IPV6_ADDRESS *, struct
t_ing_tunnel_info *, struct INGRESS_VRF_RECORD *, unsigned int, const struct
INGRESS_ILM_RECORD *, unsigned char, struct INTERFACE_DEST_INFO *, unsigned
int, short unsigned int, short unsigned int, struct DPISUB_VFP_INFO *, const
struct VFP_INGRESS_SAP_INFO *, struct t_ing_qos *, const struct DEST_INDICES *,
struct t_ing_special_ucast_l3_info *)

#5  0x000000000090923b in gt_ggc_mx_lang_tree_node (x_p=0x7ffff4137d20)
    at ./gt-cp-tree.h:543
543                   gt_ggc_m_9tree_node
((*x).generic.type_non_common.with_lang_specific.common.common.typed.type);
(gdb) p debug_generic_expr ((tree)x)
struct tVfpPacketDesc *
$43 = void
(gdb) down
#4  0x00000000009093c9 in gt_ggc_mx_lang_tree_node (x_p=0x7ffff40f9348)
    at ./gt-cp-tree.h:567
567                   gt_ggc_m_9tree_node
((*x).generic.type_non_common.with_lang_specific.common.name);
(gdb) p debug_generic_expr ((tree)x)
struct  %[cl] 
$44 = void

looking at how TYPE_NAME of that record evolves.  I suspect it should have
remained the TYPE_DECL and not released to be re-allocated as lang-specific
data.

Ok, so I think this is a dup of PR70297.