https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78334
Bug ID: 78334
Summary: unpacking constexpr char array as template parameters
list inside constexpr lambda failed when passed as
auto non-type template parameter
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: tomilovanatoliy at yandex dot ru
Target Milestone: ---
Created attachment 40031
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40031&action=edit
source file
I tried to unpack constexpr char array to template parameters list using
constexpr lambda (see attached code) and gives internal compiler error
described below.
Technically I can do it, if I use `template< std::size_t size, char const (&
value)[size] >` template parameter pack for variable template. I.e. the problem
triggered namely by `auto const &` template non-type parameter.
Version:
7.0.0 20161112
System type:
x86_64-pc-linux-gnu
Command line:
$ g++ prog.cc -Wall -Wextra -v -I/usr/local/boost-1.62.0/include -std=gnu++1z
-pedantic "-Wall" "-Wextra"
Output of the compiler:
Using built-in specs.
COLLECT_GCC=/usr/local/gcc-head/bin/g++
COLLECT_LTO_WRAPPER=/usr/local/gcc-head/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/heads/gcc/gcc-source/configure
--prefix=/usr/local/gcc-head --enable-languages=c,c++ --enable-lto
--disable-multilib --without-ppl --without-cloog-ppl --enable-checking=release
--disable-nls
Thread model: posix
gcc version 7.0.0 20161112 (experimental) (GCC)
COLLECT_GCC_OPTIONS='-o' 'prog.exe' '-I' '/usr/local/boost-sml/include' '-I'
'/usr/local/range-v3/include' '-Wpedantic' '-std=gnu++1z' '-I'
'/usr/local/boost-1.62.0/include' '-L/usr/local/boost-1.62.0/lib' '-v' '-Wall'
'-Wextra' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
/usr/local/gcc-head/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/cc1plus -quiet -v -I
/usr/local/boost-sml/include -I /usr/local/range-v3/include -I
/usr/local/boost-1.62.0/include -imultiarch x86_64-linux-gnu -D_GNU_SOURCE
prog.cc -quiet -dumpbase prog.cc -mtune=generic -march=x86-64 -auxbase prog
-Wpedantic -Wall -Wextra -std=gnu++1z -version -o /tmp/ccZUTC1X.s
GNU C++14 (GCC) version 7.0.0 20161112 (experimental) (x86_64-pc-linux-gnu)
compiled by GNU C version 7.0.0 20161112 (experimental), GMP version
5.1.2, MPFR version 3.1.2, MPC version 1.0.1, isl version none
warning: GMP header version 5.1.2 differs from library version 5.0.2.
warning: MPFR header version 3.1.2 differs from library version 3.1.0-p3.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/local/gcc-head/lib/gcc/x86_64-pc-linux-gnu/7.0.0/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/boost-sml/include
/usr/local/range-v3/include
/usr/local/boost-1.62.0/include
/usr/local/gcc-head/lib/gcc/x86_64-pc-linux-gnu/7.0.0/../../../../include/c++/7.0.0
/usr/local/gcc-head/lib/gcc/x86_64-pc-linux-gnu/7.0.0/../../../../include/c++/7.0.0/x86_64-pc-linux-gnu
/usr/local/gcc-head/lib/gcc/x86_64-pc-linux-gnu/7.0.0/../../../../include/c++/7.0.0/backward
/usr/local/gcc-head/lib/gcc/x86_64-pc-linux-gnu/7.0.0/include
/usr/local/include
/usr/local/gcc-head/include
/usr/local/gcc-head/lib/gcc/x86_64-pc-linux-gnu/7.0.0/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
GNU C++14 (GCC) version 7.0.0 20161112 (experimental) (x86_64-pc-linux-gnu)
compiled by GNU C version 7.0.0 20161112 (experimental), GMP version
5.1.2, MPFR version 3.1.2, MPC version 1.0.1, isl version none
warning: GMP header version 5.1.2 differs from library version 5.0.2.
warning: MPFR header version 3.1.2 differs from library version 3.1.0-p3.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: ceca72188b7a96c7095801870930d855
prog.cc: In instantiation of 'struct<lambda>':
prog.cc:51:64: required from 'constexpr const auto constexpr_string<s>'
prog.cc:59:44: required from here
prog.cc:51:80: internal compiler error: Segmentation fault
constexpr auto constexpr_string = iterate< std::size(value) >{}([] (auto... i)
constexpr { return std::integer_sequence< char_type, value[i]... >{}; });
^~~~~~~~~
0xaf5f3f crash_signal
/home/heads/gcc/gcc-source/gcc/toplev.c:338
0x604f00 template_parms_to_args
/home/heads/gcc/gcc-source/gcc/cp/pt.c:4302
0x609ca5 current_template_args
/home/heads/gcc/gcc-source/gcc/cp/pt.c:4330
0x609ca5 do_auto_deduction(tree_node*, tree_node*, tree_node*, int,
auto_deduction_context, tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:24880
0x61ad96 convert_template_argument
/home/heads/gcc/gcc-source/gcc/cp/pt.c:7304
0x61e786 coerce_template_parms
/home/heads/gcc/gcc-source/gcc/cp/pt.c:7794
0x61f5b9 lookup_template_class_1
/home/heads/gcc/gcc-source/gcc/cp/pt.c:8366
0x61f5b9 lookup_template_class(tree_node*, tree_node*, tree_node*, tree_node*,
int, int)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:8711
0x620e29 tsubst_aggr_type
/home/heads/gcc/gcc-source/gcc/cp/pt.c:11592
0x613353 tsubst_decl
/home/heads/gcc/gcc-source/gcc/cp/pt.c:11957
0x618ee7 tsubst(tree_node*, tree_node*, int, tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:12984
0x612960 tsubst_decl
/home/heads/gcc/gcc-source/gcc/cp/pt.c:11818
0x618ee7 tsubst(tree_node*, tree_node*, int, tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:12984
0x626ce1 instantiate_class_template_1
/home/heads/gcc/gcc-source/gcc/cp/pt.c:10153
0x626ce1 instantiate_class_template(tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:10487
0x688fa5 complete_type(tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/typeck.c:133
0x616880 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:17419
0x617174 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:16733
0x610fff tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:16043
0x60e4db tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:21897
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
