[Bug c++/105956] New: internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[Bug c++/105956] New: internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[msc at linux dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

            Bug ID: 105956
           Summary: internal compiler error: in
                    iterative_hash_template_arg, at cp/pt.cc:1819
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: msc at linux dot ibm.com
  Target Milestone: ---

Bumped into this error while compiling boost.fiber with upstream GCC:

$ git gcc-descr HEAD
r12-9379-g1158fe43407568

$ "/tmp/gcc-install/bin/gcc" -freport-bug  -fvisibility-inlines-hidden -fPIC
-m64 -pthread -O0 -fno-inline -Wall -g -fvisibility=hidden 
-DBOOST_ALL_NO_LIB=1 -DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_FIBERS_DYN_LINK=1
-DBOOST_FIBERS_SOURCE -DBOOST_FILESYSTEM_DYN_LINK=1  -I"../../.."  -c -o
"../../../bin.v2/libs/fiber/build/gcc-custom/debug/threading-multi/visibility-hidden/scheduler.o"
"../../../libs/fiber/src/scheduler.cpp"
In file included from ../../../boost/intrusive/options.hpp:19,
                 from ../../../boost/intrusive/list_hook.hpp:22,
                 from ../../../boost/intrusive/list.hpp:20,
                 from ../../../boost/fiber/scheduler.hpp:17,
                 from ../../../libs/fiber/src/scheduler.cpp:7:
../../../boost/intrusive/pack_options.hpp: In instantiation of ‘struct
boost::intrusive::invert_typelist_impl<boost::intrusive::typelist<boost::intrusive::slist_defaults,
boost::intrusive::member_hook<boost::fibers::waker_with_hook,
boost::intrusive::slist_member_hook<>,
&boost::fibers::waker_with_hook::waker_queue_hook_>,
boost::intrusive::constant_time_size<false>, boost::intrusive::cache_last<true>
>, boost::intrusive::index_tuple<0, 1, 2, 3> >’:
../../../boost/intrusive/pack_options.hpp:190:71:   required from ‘struct
boost::intrusive::invert_typelist<boost::intrusive::typelist<boost::intrusive::slist_defaults,
boost::intrusive::member_hook<boost::fibers::waker_with_hook,
boost::intrusive::slist_member_hook<>,
&boost::fibers::waker_with_hook::waker_queue_hook_>,
boost::intrusive::constant_time_size<false>, boost::intrusive::cache_last<true>
> >’
../../../boost/intrusive/pack_options.hpp:230:55:   required from ‘struct
boost::intrusive::pack_options<boost::intrusive::slist_defaults,
boost::intrusive::member_hook<boost::fibers::waker_with_hook,
boost::intrusive::slist_member_hook<>,
&boost::fibers::waker_with_hook::waker_queue_hook_>,
boost::intrusive::constant_time_size<false>, boost::intrusive::cache_last<true>
>’
../../../boost/intrusive/slist.hpp:2149:15:   required from ‘struct
boost::intrusive::make_slist<boost::fibers::waker_with_hook,
boost::intrusive::member_hook<boost::fibers::waker_with_hook,
boost::intrusive::slist_member_hook<>,
&boost::fibers::waker_with_hook::waker_queue_hook_>,
boost::intrusive::constant_time_size<false>, boost::intrusive::cache_last<true>
>’
../../../boost/intrusive/slist.hpp:2173:7:   required from ‘class
boost::intrusive::slist<boost::fibers::waker_with_hook,
boost::intrusive::member_hook<boost::fibers::waker_with_hook,
boost::intrusive::slist_member_hook<>,
&boost::fibers::waker_with_hook::waker_queue_hook_>,
boost::intrusive::constant_time_size<false>, boost::intrusive::cache_last<true>
>’
../../../boost/fiber/waker.hpp:73:36:   required from here
../../../boost/intrusive/pack_options.hpp:164:29: internal compiler error: in
iterative_hash_template_arg, at cp/pt.cc:1819
  164 |    static const std::size_t last_idx = sizeof_typelist<Typelist>::value
- 1;
      |                             ^~~~~~~~
0x6ec942 iterative_hash_template_arg(tree_node*, unsigned int)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:1819
0xb105c5 iterative_hash_template_arg(tree_node*, unsigned int)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:1829
0xb10fc8 hash_tmpl_and_args
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:1769
0xb10fc8 spec_hasher::hash(tree_node*, tree_node*)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:1776
0xb3389b tsubst_decl
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:14991
0xb26d87 tsubst_copy
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:17066
0xb2a720 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:21390
0xb2a2f6 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:20434
0xb2bb15 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:20283
0xb35d08 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:19595
0xb4b4dc tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13580
0xb54d8f tsubst_aggr_type
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13796
0xb54d8f tsubst_aggr_type
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13753
0xb49154 tsubst(tree_node*, tree_node*, int, tree_node*)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:16282
0xb35497 gen_elem_of_pack_expansion_instantiation
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:12749
0xb35497 tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13417
0xb4b6e2 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13566
0xb4b905 tsubst_argument_pack(tree_node*, tree_node*, int, tree_node*)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13517
0xb4b6b4 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13578
0xb54d8f tsubst_aggr_type
        /home/mscastanho/dev/gcc/gcc/cp/pt.cc:13796
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Preprocessed source stored into /tmp/ccVLIwjb.out file, please attach this to
your bugreport.


I'm not that familiar with the code to be able to create a smaller reproducer,
but I'm attaching the pre-processed source generated by -freport-bug.

I was able to reproduce this both on ppc64le and x86_64. GCC configured with:
<gcc-path>/configure --prefix=/tmp/gcc-install --enable-languages=c,c++
--disable-bootstrap --disable-multilib


After doing a quick bisect I suspect the issue was introduced by the following
commit:

commit cb7fd1ea85feea7ef65328330fc2577a95e99400
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri Jun 10 16:09:48 2022 -0400

    c++: optimize specialization of nested templated classes

[Bug c++/105956] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I don't actually see the pre-processed source, can you attach it?

[Bug c++/105956] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[msc at linux dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #2 from Matheus Castanho <msc at linux dot ibm.com> ---
Created attachment 53129
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53129&action=edit
pre-processed source generated by -freport-bug

[Bug c++/105956] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[msc at linux dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #3 from Matheus Castanho <msc at linux dot ibm.com> ---
Sorry, looks like the original file was too large and didn't get attached when
I created the bug. I attached a gzip compressed version now.

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
   Target Milestone|---                         |13.0
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-06-13
            Summary|internal compiler error: in |[13 Regression] internal
                   |iterative_hash_template_arg |compiler error: in
                   |, at cp/pt.cc:1819          |iterative_hash_template_arg
                   |                            |, at cp/pt.cc:1819
           Priority|P3                          |P1

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Thanks, reproduced.

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
So far reduced to

template <int...> struct index_tuple;
template <unsigned long, typename = index_tuple<>> struct build_number_seq;
template <unsigned long Num, int... Indexes>
struct build_number_seq<Num, index_tuple<Indexes...>>
    : build_number_seq<Num - 1, index_tuple<sizeof...(Indexes)>> {};
template <int... Indexes> struct build_number_seq<0, index_tuple<Indexes...>> {
  typedef index_tuple<Indexes...> type;
};
template <class> struct typelist;
template <int, typename> struct typelist_element;
template <typename Head, typename... Tail>
struct typelist_element<0, typelist<Head, Tail...>> {
  typedef Head type;
};
template <class> struct sizeof_typelist;
template <class... Types> struct sizeof_typelist<typelist<Types...>> {
  static const long value = sizeof...(Types);
};
template <class, class> struct invert_typelist_impl;
template <class Typelist, int... Ints>
struct invert_typelist_impl<Typelist, index_tuple<Ints...>> {
  static const long last_idx = sizeof_typelist<Typelist>::value - 1;
  typedef typelist<
      typename typelist_element<last_idx - Ints, Typelist>::type...>
      type;
};
template <class> struct invert_typelist;
template <class... Types> struct invert_typelist<typelist<Types...>> {
  typedef typename invert_typelist_impl<
      typelist<Types...>,
      typename build_number_seq<sizeof...(Types)>::type>::type type;
};
template <class> struct do_pack;
struct hook_defaults;
typedef do_pack<invert_typelist<typelist<hook_defaults>>::type> type;

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #6 from Martin Liška <marxin at gcc dot gnu.org> ---
Note I see the same error for inkscape package.

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #7 from Martin Liška <marxin at gcc dot gnu.org> ---
And I reduced to the pretty same code snippet as Marek did.

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nyh at math dot technion.ac.il

--- Comment #8 from Martin Liška <marxin at gcc dot gnu.org> ---
*** Bug 106087 has been marked as a duplicate of this bug. ***

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |byteslice at airmail dot cc

--- Comment #9 from Patrick Palka <ppalka at gcc dot gnu.org> ---
*** Bug 106152 has been marked as a duplicate of this bug. ***

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:7b90f07f778caa5e09f3dc20a8c3da1f4cf60c20

commit r13-1565-g7b90f07f778caa5e09f3dc20a8c3da1f4cf60c20
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Jul 7 16:46:29 2022 -0400

    c++: generic targs and identity substitution [PR105956]

    In r13-1045-gcb7fd1ea85feea I assumed that substitution into generic
    DECL_TI_ARGS corresponds to an identity mapping of the given arguments,
    and hence its safe to always elide such substitution.  But this PR
    demonstrates that such a substitution isn't always the identity mapping,
    in particular when there's an ARGUMENT_PACK_SELECT argument, which gets
    handled specially during substitution:

      * when substituting an APS into a template parameter, we strip the
        APS to its underlying argument;
      * and when substituting an APS into a pack expansion, we strip the
        APS to its underlying argument pack.

    In this testcase, when expanding the pack expansion pattern (idx + Ns)...
    with Ns={0,1}, we specialize idx twice, first with Ns=APS<0,{0,1}> and
    then Ns=APS<1,{0,1}>.  The DECL_TI_ARGS of idx are the generic template
    arguments of the enclosing class template impl, so before r13-1045,
    we'd substitute into its DECL_TI_ARGS which gave Ns={0,1} as desired.
    But after r13-1045, we elide this substitution and end up attempting to
    hash the original Ns argument, an APS, which ICEs.

    So this patch reverts that part of r13-1045.  I considered using
    preserve_args in this case instead, but that'd break the static_assert
    in the testcase because preserve_args always strips APS to its
    underlying argument, but here we want to strip it to its underlying
    argument pack, so we'd incorrectly end up forming the specializations
    impl<0>::idx and impl<1>::idx instead of impl<0,1>::idx.

    Although we can't elide the substitution into DECL_TI_ARGS in light of
    ARGUMENT_PACK_SELECT, it should still be safe to elide template argument
    coercion in the case of a non-template decl, which this patch preserves.

    It's unfortunate that we need to remove this optimization just because
    it doesn't hold for one special tree code.  So this patch implements a
    heuristic in tsubst_template_args to avoid allocating a new TREE_VEC if
    the substituted elements are identical to those of a level from ARGS, as
    well as a similar heuristic for tsubst_argument_pack.  It turns out that
    about 40% of all calls to tsubst_template_args benefit from this, and it
    reduces memory usage by about 4% for e.g. range-v3's zip.cpp (relative to
    r13-1045) which more than makes up for the reversion.

            PR c++/105956

    gcc/cp/ChangeLog:

            * pt.cc (template_arg_to_parm): Define.
            (tsubst_argument_pack): Try to reuse the corresponding
            ARGUMENT_PACK from 'args' when substituting into a generic
            ARGUMENT_PACK for a variadic template parameter.
            (tsubst_template_args): Move variable declarations closer to
            their first use.  Replace 'orig_t' with 'r'.  Rename 'need_new'
            to 'const_subst_p'.  Heuristically detect if the substituted
            elements are identical to that of a level from 'args' and avoid
            allocating a new TREE_VEC if so.  Add sanity check for the
            length of the new TREE_VEC, and remove dead ARGUMENT_PACK_P test.
            (tsubst_decl) <case TYPE_DECL, case VAR_DECL>: Revert
            r13-1045-gcb7fd1ea85feea change for avoiding substitution into
            DECL_TI_ARGS, but still avoid coercion in this case.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/variadic183.C: New test.

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #11 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed.

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[herrtimson at yahoo dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #12 from tt_1 <herrtimson at yahoo dot de> ---
may I ask kindly - this was seemingly reported with a git version of gcc-12, so
is there still a need for backporting the fix to that branch as well?

[Bug c++/105956] [13 Regression] internal compiler error: in iterative_hash_template_arg, at cp/pt.cc:1819

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105956

--- Comment #13 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to tt_1 from comment #12)
> may I ask kindly - this was seemingly reported with a git version of gcc-12,
> so is there still a need for backporting the fix to that branch as well?

No, only the master branch was affected.