[Bug c++/70776] [4.9/5/6/7 Regression] ICE on invalid code on x86_64-linux-gnu: Segmentation fault (program cc1plus)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70776

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2016-04-25
     Ever confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  Infinite recursion via

#0  0x0000000000b0051e in ggc_internal_alloc (
    size=<error reading variable: Cannot access memory at address
0x7ffffbffeed8>, f=<error reading variable: Cannot access memory at address
0x7ffffbffeed0>, 
    s=<error reading variable: Cannot access memory at address 0x7ffffbffeec8>,
n=<error reading variable: Cannot access memory at address 0x7ffffbffeec0>)
    at /space/rguenther/src/svn/trunk/gcc/ggc-page.c:1267
#1  0x0000000000d3e569 in ggc_internal_cleared_alloc (size=40, f=0x0, s=0, n=1)
    at /space/rguenther/src/svn/trunk/gcc/ggc-common.c:116
#2  0x00000000013e9456 in ggc_internal_cleared_alloc (s=40)
    at /space/rguenther/src/svn/trunk/gcc/ggc.h:148
#3  0x00000000013e948a in ggc_alloc_cleared_tree_node_stat (s=40)
    at /space/rguenther/src/svn/trunk/gcc/ggc.h:292
#4  0x00000000013ef8c2 in make_tree_vec_stat (len=2)
    at /space/rguenther/src/svn/trunk/gcc/tree.c:2281
#5  0x000000000081467f in coerce_template_parms (
    parms=<tree_vec 0x7ffff69da758>, args=<tree_vec 0x7ffff67ee438>, 
    in_decl=<template_decl 0x7ffff69f1100 B>, complain=0, 
    require_all_args=true, use_default_args=true)
    at /space/rguenther/src/svn/trunk/gcc/cp/pt.c:7594
#6  0x00000000008151a1 in coerce_innermost_template_parms (
    parms=<tree_list 0x7ffff69da780>, args=<tree_vec 0x7ffff67ee438>, 
    in_decl=<template_decl 0x7ffff69f1100 B>, complain=0, 
    require_all_args=true, use_default_args=true)
    at /space/rguenther/src/svn/trunk/gcc/cp/pt.c:7820
#7  0x0000000000817ceb in lookup_template_class_1 (
    d1=<identifier_node 0x7ffff69efd68 B>, arglist=<tree_vec 0x7ffff67ee438>, 
    in_decl=<tree 0x0>, context=<translation_unit_decl 0x7ffff6893168>, 
    entering_scope=0, complain=0)
    at /space/rguenther/src/svn/trunk/gcc/cp/pt.c:8297
#8  0x000000000081ae6b in lookup_template_class (
    d1=<record_type 0x7ffff69df7e0 B>, arglist=<tree_vec 0x7ffff67ee438>, 
    in_decl=<tree 0x0>, context=<translation_unit_decl 0x7ffff6893168>, 
    entering_scope=0, complain=0)
    at /space/rguenther/src/svn/trunk/gcc/cp/pt.c:8638
#9  0x00000000008274a3 in tsubst_aggr_type (t=<record_type 0x7ffff69df7e0 B>, 
    args=<tree_vec 0x7ffff67ef040>, complain=0, in_decl=<tree 0x0>, 
    entering_scope=0) at /space/rguenther/src/svn/trunk/gcc/cp/pt.c:11425
#10 0x000000000082fe5d in tsubst (t=<record_type 0x7ffff69df7e0 B>, 
    args=<tree_vec 0x7ffff67ef040>, complain=0, in_decl=<tree 0x0>)
    at /space/rguenther/src/svn/trunk/gcc/cp/pt.c:12895
#11 0x0000000000833e7d in tsubst_qualified_id (
    qualified_id=<scope_ref 0x7ffff69daac8>, args=<tree_vec 0x7ffff67ef040>, 
    complain=0, in_decl=<tree 0x0>, done=true, address_p=false)
    at /space/rguenther/src/svn/trunk/gcc/cp/pt.c:13734
...

Clang detects:

> clang++ -S t.ii
t.ii:6:34: fatal error: recursive template instantiation exceeded maximum depth
      of 256


Not sure if the testcase is thus invalid (but we should diagnose it instead
of crashing).