https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97093
Bug ID: 97093
Summary: ICE on C++20 code: memory corruption when chaining
requirements (in hashtab_chk_error, at
hash-table.c:137)
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dimitri.gorokhovik at free dot fr
Target Milestone: ---
The following code:
template <typename T>
concept C = requires (T t)
{
requires t.some_const < 2
#if BUG
|| requires { t.some_fn (); }
#endif
;
};
template <unsigned, unsigned>
struct c
{};
template <typename T>
concept P = requires (T t, c <0, 1> v)
{
#if BUG
{ t (v) };
#else
true;
#endif
};
template <P auto, P auto ...>
struct m
{
constexpr auto operator () (C auto) const
{};
};
struct pc
{
constexpr auto operator () (C auto) const
{};
};
constexpr auto cc = pc {};
constexpr auto mmcc = m <cc> {};
when compiled as:
g++ -std=c++20 -fconcepts-diagnostics-depth=3 -o bug-5.o -c bug-5.cpp -DBUG=1
gives an ICE (stack traces below) with a frequency of 60-70% -- might need to
run it a few times to see. Defining BUG to > 0 and setting
-fconcepts-diagnostics-depth to > 2 are required to reproduce.
Version:
g++ (GCC) 11.0.0 20200917 (experimental)
Output from the compiler:
dgorokho@desktop:~/Sources/Rete$ /home/dgorokho/gcc-trunk/trunk/dist/bin/g++
-std=c++20 -fconcepts-diagnostics-depth=25 -o bug-5.o -c bug-5.cpp -DBUG=1
bug-5.cpp:43:28: error: placeholder constraints not satisfied
43 | constexpr auto mmcc = m <cc> {};
| ^
bug-5.cpp:43:28: note: constraints not satisfied
bug-5.cpp:18:9: required for the satisfaction of ‘P<pc>’
bug-5.cpp:18:13: in requirements with ‘T t’, ‘c<0, 1> v’ [with T = pc]
bug-5.cpp:21:7: note: the required expression ‘t(v)’ is invalid, because
21 | { t (v) };
| ~~^~~
bug-5.cpp:21:7: error: no match for call to ‘(pc) (c<0, 1>&)’
bug-5.cpp:37:18: note: candidate: ‘template<class auto:2> requires C<auto:2>
constexpr auto pc::operator()(auto:2) const’
37 | constexpr auto operator () (C auto) const
| ^~~~~~~~
bug-5.cpp:37:18: note: template argument deduction/substitution failed:
bug-5.cpp:37:18: note: constraints not satisfied
bug-5.cpp: In substitution of ‘template<class auto:2> requires C<auto:2>
constexpr auto pc::operator()(auto:2) const [with auto:2 = c<0, 1>]’:
bug-5.cpp:21:7: required from here
bug-5.cpp:2:9: required for the satisfaction of ‘C<auto:2>’ [with auto:2 =
c<0, 1>]
bug-5.cpp:2:14: in requirements with ‘T t’ [with T = c<0, 1>]
bug-5.cpp:6:3: note: nested requirement ‘((t.some_const < 2) ||
requires{t.some_fn();})’ is not satisfied, because
4 | requires t.some_const < 2
| ~~~~~~~~~~~~~~~~
5 | #if BUG
| ~~~~~~~
6 | || requires { t.some_fn (); }
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hash table checking failed: equal operator returns true for a pair of values
with a different hash value
bug-5.cpp:4:12: internal compiler error: in hashtab_chk_error, at
hash-table.c:137
4 | requires t.some_const < 2
| ~~~~~~~~~^~~~~~~~~~~~~~~~
5 | #if BUG
| ~~~~~~~
6 | || requires { t.some_fn (); }
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0x88c89a hashtab_chk_error()
../../src/gcc/hash-table.c:137
0x8f276c hash_table<sat_hasher, false, xcallocator>::verify(sat_entry* const&,
unsigned int)
../../src/gcc/hash-table.h:1033
0x8f292b hash_table<sat_hasher, false, xcallocator>::find_with_hash(sat_entry*
const&, unsigned int)
../../src/gcc/hash-table.h:918
0x8f0806 satisfy_constraint_r
../../src/gcc/hash-table.h:430
0x8f05c5 satisfy_constraint_r
../../src/gcc/cp/constraint.cc:2482
0x8f0db8 satisfy_constraint
../../src/gcc/cp/constraint.cc:2701
0x8f00b3 diagnose_nested_requirement
../../src/gcc/cp/constraint.cc:3413
0x8f00b3 diagnose_requirement
../../src/gcc/cp/constraint.cc:3433
0x8f00b3 diagnose_requires_expr
../../src/gcc/cp/constraint.cc:3457
0x8f00b3 diagnose_atomic_constraint
../../src/gcc/cp/constraint.cc:3493
0x8f0c58 satisfy_constraint_r
../../src/gcc/cp/constraint.cc:2652
0x8f0db8 satisfy_constraint
../../src/gcc/cp/constraint.cc:2701
0x8f20ed constraint_satisfaction_value
../../src/gcc/cp/constraint.cc:2719
0x8f2187 diagnose_constraints(unsigned int, tree_node*, tree_node*)
../../src/gcc/cp/constraint.cc:3563
0xa5196c fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, conversion**, bool,
bool)
../../src/gcc/cp/pt.c:21317
0x8a1378 print_z_candidate
../../src/gcc/cp/call.c:3788
0x8a2e2f print_z_candidates
../../src/gcc/cp/call.c:3868
0x8b0713 build_op_call_1
../../src/gcc/cp/call.c:4893
0x8b0713 build_op_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, int)
../../src/gcc/cp/call.c:4929
0xa704ce finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
../../src/gcc/cp/semantics.c:2724
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
