https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70204
Bug ID: 70204
Summary: ICE on x86_64-linux-gnu in non_const_var_error, at
cp/constexpr.c:2764
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: su at cs dot ucdavis.edu
Target Milestone: ---
The following (invalid) code causes an ICE when compiled with the current GCC
trunk on x86_64-linux-gnu in both 32-bit and 64-bit modes.
This is a regression from 5.3.x.
$ g++-trunk -v
Using built-in specs.
COLLECT_GCC=g++-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/usr/local/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 6.0.0 20160311 (experimental) [trunk revision 234134] (GCC)
$
$ g++-5.3 -c small.cpp
small.cpp: In function ‘void fn1()’:
small.cpp:7:9: error: ‘y’ cannot appear in a constant-expression
fn1 < y, I > ();
^
$
$ g++-trunk -c small.cpp
small.cpp: In function ‘void fn1()’:
small.cpp:7:9: error: the value of ‘y’ is not usable in a constant expression
fn1 < y, I > ();
^
small.cpp:6:24: note: ‘y’ was not initialized with a constant expression
const int x = I * a, y = x;
^
small.cpp: In instantiation of ‘void fn1() [with int N = 0; int I = 0]’:
small.cpp:13:17: required from here
small.cpp:7:16: error: no matching function for call to ‘fn1()’
fn1 < y, I > ();
~~~~~~~~~~~~~^~
small.cpp:4:6: note: candidate: template<int N, int I> void fn1()
void fn1 ()
^~~
small.cpp:4:6: note: template argument deduction/substitution failed:
small.cpp:7:16: error: the value of ‘y’ is not usable in a constant expression
fn1 < y, I > ();
~~~~~~~~~~~~~^~
small.cpp:7:16: internal compiler error: in non_const_var_error, at
cp/constexpr.c:2764
0x8440c7 non_const_var_error
../../gcc-source-trunk/gcc/cp/constexpr.c:2764
0x84e21d cxx_eval_constant_expression
../../gcc-source-trunk/gcc/cp/constexpr.c:3336
0x84c9d0 cxx_eval_constant_expression
../../gcc-source-trunk/gcc/cp/constexpr.c:3720
0x852c19 cxx_eval_outermost_constant_expr
../../gcc-source-trunk/gcc/cp/constexpr.c:3939
0x6940a7 convert_nontype_argument
../../gcc-source-trunk/gcc/cp/pt.c:6378
0x6940a7 convert_template_argument
../../gcc-source-trunk/gcc/cp/pt.c:7254
0x6a05eb coerce_template_parms
../../gcc-source-trunk/gcc/cp/pt.c:7715
0x6b90d1 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, bool, bool)
../../gcc-source-trunk/gcc/cp/pt.c:17625
0x61588b print_z_candidate
../../gcc-source-trunk/gcc/cp/call.c:3440
0x6174f6 print_z_candidates
../../gcc-source-trunk/gcc/cp/call.c:3510
0x621167 build_new_function_call(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, bool, int)
../../gcc-source-trunk/gcc/cp/call.c:4120
0x7bba69 finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
../../gcc-source-trunk/gcc/cp/semantics.c:2453
0x68a3f6 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
../../gcc-source-trunk/gcc/cp/pt.c:16623
0x67cddf tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../gcc-source-trunk/gcc/cp/pt.c:15795
0x67d480 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../gcc-source-trunk/gcc/cp/pt.c:15111
0x67c803 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../gcc-source-trunk/gcc/cp/pt.c:15097
0x67e320 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../gcc-source-trunk/gcc/cp/pt.c:15283
0x67a976 instantiate_decl(tree_node*, int, bool)
../../gcc-source-trunk/gcc/cp/pt.c:22006
0x6c6c42 instantiate_pending_templates(int)
../../gcc-source-trunk/gcc/cp/pt.c:22125
0x70a587 c_parse_final_cleanups()
../../gcc-source-trunk/gcc/cp/decl2.c:4599
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.
$
----------------------------------
int a;
template < int N, int I >
void fn1 ()
{
const int x = I * a, y = x;
fn1 < y, I > ();
}
int
main ()
{
fn1 < 0, 0 > ();
return 0;
}
