[Bug c++/89579] New: -Wclobbered warning false positive when compiling with -Og
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89579 Bug ID: 89579 Summary: -Wclobbered warning false positive when compiling with -Og Product: gcc Version: 9.0 Status: UNCONFIRMED Keywords: diagnostic, rejects-valid Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: abigail.buccaneer at gmail dot com Target Milestone: --- Created attachment 45884 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45884=edit Minimal reproduction When compiling with `-Wclobbered -Og`, we see false positives from the -Wclobbered warning. These don't occur with any other optimization level. This breaks our build under `-Wextra -Werror -Og`. Attached is a minimal reproduction test case. This bug is present from GCC 5.5.0 to GCC trunk (9.0.1 20190303). GCC 5.4.0 and below are not affected.
[Bug c++/85049] Internal compiler error with __integer_pack
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85049 --- Comment #1 from AbigailBuccaneer --- If `index_sequence_for` is replaced with `std::index_sequence_for` (and `#include ` is added), this code compiles fine under g++-7, but not g++-8 (where std::index_sequence_for is implemented in terms of __index_pack, similar to how it is in the code snippet above).
[Bug c++/85049] New: Internal compiler error with __integer_pack
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85049
Bug ID: 85049
Summary: Internal compiler error with __integer_pack
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: abigail.buccaneer at gmail dot com
Target Milestone: ---
The following code:
template struct index_sequence {};
template using index_sequence_for =
index_sequence<__integer_pack(sizeof...(Ts))...>;
template struct tuple {};
template int get(tuple<index_sequence_for, Ts...>);
int x = get(tuple<index_sequence_for<>>{});
fails to compile with an internal compiler error.
On gcc.godbolt.org's "gcc trunk" compiler, the output is the following:
: In substitution of 'template int
get(tuple<index_sequence<__integer_pack(sizeof ... (Ts ...))...>, Ts ...>)
[with Ts = ]':
:10:42: required from here
:10:42: internal compiler error: tree check: expected
template_parm_index, have call_expr in template_parm_level_and_index, at
cp/pt.c:20594
int x = get(tuple<index_sequence_for<>>{});
^
mmap: Invalid argument
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
And the version info is:
g++ (GCC-Explorer-Build) 8.0.1 20180322 (experimental)
On a version of g++-8 installed from the Ubuntu repositories, the output is the
following:
tuple.cpp: In substitution of ‘template int
get(tuple<std::integer_sequence, Ts ...>) [with Ts = ]’:
tuple.cpp:7:47: required from here
tuple.cpp:7:47: internal compiler error: Segmentation fault
int x = get(tuple<std::index_sequence_for<>>{});
^
Please submit a full bug report,
with preprocessed source if appropriate.
See for instructions.
And the version info is:
g++-8 (Ubuntu 8-20170923-1ubuntu2) 8.0.0 20170923 (experimental) [trunk
revision 253118]
[Bug libstdc++/84110] Null character in regex
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84110
--- Comment #1 from AbigailBuccaneer ---
From what I can tell, this isn't intentional behavior in libstdc++.
regex_scanner.h defines:
const char* _M_ecma_spec_char = "^$\\.*+?()[]{}|";
and regex_scanner.tcc tries to interpret any character not in this set of
special characters as an ordinary character token:
if (std::strchr(_M_spec_char, _M_ctype.narrow(__c, ' ')) == nullptr)
{
_M_token = _S_token_ord_char;
_M_value.assign(1, __c);
return;
}
However, the strchr specification says (emphasis mine):
Description: The strchr function locates the first occurrence of c (converted
to a char) in the string pointed to by s. ***The terminating null character is
considered to be part of the string***.
[Bug libstdc++/84110] New: Null character in regex
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84110
Bug ID: 84110
Summary: Null character in regex
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: abigail.buccaneer at gmail dot com
Target Milestone: ---
The following code, when compiled with libstdc++:
#include
int main() {
auto r = std::regex{"\0", std::size_t{1}};
}
...results in std::regex_error being thrown. My reading of the ECMAScript regex
spec says that this should be allowed, and that a null byte should match a
literal null byte:
PatternCharacter ::
SourceCharacter but not one of
^ $ \ . * + ? ( ) [ ] { } |
SourceCharacter ::
any Unicode code unit
(Elsewhere in the ECMAScript spec, it explicitly specifies that an unrelated
grammar production is 'SourceCharacter but not one of " or \ or U+ through
U+001F', so it makes sense to assume that SourceCharacter here very
intentionally includes null.)
Clang/libc++ seems to agree with this reading, and successfully compiles and
runs the following:
#include
#include
int main() {
auto null = std::string{"\0", std::size_t{1}};
std::smatch match_results;
assert(std::regex_match(null, match_results, std::regex{null}));
assert(match_results.position() == 0
&& match_results.length() == 1
&& match_results[0] == null);
}
[Bug c++/83290] New: Expressions in anonymous unions inside class templates can't reference the union's members
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83290
Bug ID: 83290
Summary: Expressions in anonymous unions inside class templates
can't reference the union's members
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: abigail.buccaneer at gmail dot com
Target Milestone: ---
The following code compiles fine (with -std=c++14):
struct A {
union {
int x;
char y[sizeof(x)];
decltype(x) z;
static_assert(sizeof(y) == sizeof(z), "");
};
};
But fails when the struct is replaced with a struct template and instantiated
as follows:
template struct T {
union {
int x;
char y[sizeof(x)];
decltype(x) z;
static_assert(sizeof(y) == sizeof(z), "");
};
};
template struct T;
The errors all say essentially the same thing:
:13:23: error: 'int Tx' is
inaccessible within this context
char y[sizeof(x)];
~^~
[Bug c++/60199] New: 'error: field initializer is not constant' error when initializing static member function pointer to a function
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60199
Bug ID: 60199
Summary: 'error: field initializer is not constant' error when
initializing static member function pointer to a
function
Product: gcc
Version: 4.8.2
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: abigail.buccaneer at gmail dot com
The following code compiles in Clang 3.3, but not GCC 4.8.2:
//---
// g++ -std=c++11 -Wall -Wextra -pedantic
void f() {}
static constexpr void (*g1)() = f; // ok
static constexpr void (*g2)() = f; // ok
struct S {
static constexpr void (*g3)() = f; // ok
static constexpr void (*g4)() = f; // error: field initializer is not
constant
};
//---
