[Bug c++/115600] UndefinedBehaviorSanitizer doesn't seem to like modules
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115600 --- Comment #2 from Christopher Di Bella --- I forgot that `gcc -v` can provide config options. ``` $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/14.1.1/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: /build/gcc/src/gcc/configure --enable-languages=ada,c,c++,d,fortran,go,lto,m2,objc,obj-c++,rust --enable-bootstrap --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://gitlab.archlinux.org/archlinux/packaging/packages/gcc/-/issues --with-build-config=bootstrap-lto --with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit --enable-cet=auto --enable-checking=release --enable-clocale=gnu --enable-default-pie --enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object --enable-libstdcxx-backtrace --enable-link-serialization=1 --enable-linker-build-id --enable-lto --enable-multilib --enable-plugin --enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch --disable-werror Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 14.1.1 20240522 (GCC) ```
[Bug c++/115600] New: UndefinedBehaviorSanitizer doesn't seem to like modules
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115600 Bug ID: 115600 Summary: UndefinedBehaviorSanitizer doesn't seem to like modules Product: gcc Version: 14.1.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: cjdb.ns at gmail dot com Target Milestone: --- Created attachment 58498 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58498&action=edit Preprocessed source ## GCC info ``` $ gcc --version gcc (GCC) 14.1.1 20240522 Copyright (C) 2024 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ``` ## System type ``` $ lsb_release -a LSB Version:n/a Distributor ID: Arch Description:Arch Linux Release:rolling Codename: n/a ``` ## How GCC was configured/built Arch default ## Command line Original invocation ``` /usr/bin/g++ -fdiagnostics-color=always -fstack-protector-strong -fvisibility=hidden -Werror -pedantic -Wall -Wattributes -Wcast-align -Wconversion -Wdouble-promotion -Wextra -Wformat=2 -Wnon-virtual-dtor -Wnull-dereference -Wodr -Wold-style-cast -Woverloaded-virtual -Wshadow -Wsign-conversion -Wsign-promo -Wunused -Wno-ignored-attributes -Wno-cxx-attribute-extension -Wno-gnu-include-next -Wno-private-header -Wno-unused-command-line-argument -D_GLIBCXX_ASSERTIONS -fsanitize=address,undefined -g -std=gnu++23 -MD -MT source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o -MF source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o.d -fmodules-ts -fmodule-mapper=source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o.modmap -MD -fdeps-format=p1689r5 -x c++ -o source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o -c ~/projects/project-template-3/build/test/default-options/Output/gnu-toolchain.test.tmp/gnu_toolchain/source/module_interface/greeter_module.cpp ``` With some experimenting, I was able to minimise it to this. Note that the culprit is `-fsanitize=undefined`: it'll work fine without that (and with `-fsanitize=address`). ``` /usr/bin/g++ -fsanitize=undefined -std=gnu++23 -fmodules-ts -fmodule-mapper=source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o.modmap -MD -fdeps-format=p1689r5 -x c++ ~/projects/pr oject-template-3/build/test/default-options/Output/gnu-toolchain.test.tmp/gnu_toolchain/source/module_interface/greeter_module.cpp ``` ## Diagnostic ``` internal compiler error: in tree_node, at cp/module.cc:9428 4 | export module greeter; |^~ 0x217b27a internal_error(char const*, ...) ???:0 0x703e87 fancy_abort(char const*, int, char const*) ???:0 0x8237da depset::hash::find_dependencies(module_state*) ???:0 0x829996 module_state::write_begin(elf_out*, cpp_reader*, module_state_config&, unsigned int&) ???:0 0x839c57 finish_module_processing(cpp_reader*) ???:0 0x7ccdfd c_parse_final_cleanups() ???:0 0x9c4fb2 c_common_parse_file() ???:0 ```
[Bug libstdc++/113283] missing C++26 freestanding headers.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113283 Christopher Di Bella changed: What|Removed |Added CC||cjdb.ns at gmail dot com --- Comment #8 from Christopher Di Bella --- I briefly suggested moving `` into Clang like `` is, but nothing concrete was ever put into place. As it stands, I do not expect this to be actioned. For folks who are interested in what LLVM folks have discussed, please see the relevant [GitHub issue](https://github.com/llvm/llvm-project/issues/77373).
[Bug c++/109337] c++2a test concepts4.C passes when it should fail
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109337 --- Comment #3 from Christopher Di Bella --- This is apparently a Clang bug: the RHS of `R42c` isn't evaluated because of short-circuiting. Apologies for the noise and thanks for helping me work through it.
[Bug c++/109338] New: `S auto>` isn't valid C++20
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109338 Bug ID: 109338 Summary: `S auto>` isn't valid C++20 Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: cjdb.ns at gmail dot com Target Milestone: --- Clang and GCC disagree on whether or not this code is valid. This **may** be a relic from the Concepts TS, which Clang doesn't implement. https://godbolt.org/z/c7rGWE9s6
[Bug c++/109337] New: c++2a test concepts4.C passes when it should fail
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109337 Bug ID: 109337 Summary: c++2a test concepts4.C passes when it should fail Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: cjdb.ns at gmail dot com Target Milestone: --- Clang and GCC disagree on the validity of concepts4.C. I think Clang is correct here, because forming a reference to `void` should be ill-formed. https://godbolt.org/z/es5GxYhzd
[Bug c++/92505] Using mutable in constexpr
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92505 Christopher Di Bella changed: What|Removed |Added CC||cjdb.ns at gmail dot com --- Comment #3 from Christopher Di Bella --- Gentle ping, this has started to cause issues in the libc++ GCC CI for ranges.
[Bug c++/99701] New: std::nullptr_t can be compared with relational ops
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99701 Bug ID: 99701 Summary: std::nullptr_t can be compared with relational ops Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: cjdb.ns at gmail dot com Target Milestone: --- Created attachment 50443 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50443&action=edit Temp file for provided source The following program is valid in all versions of GCC from 4.7.1 through trunk[1]. Relational operations on std::nullptr_t don't really make sense since there's only one value. ``` auto lt = nullptr < nullptr; auto gt = nullptr > nullptr; auto le = nullptr <= nullptr; auto ge = nullptr >= nullptr; ``` This was apparently addressed by DR583/N3478 (thanks to Richard Smith for providing these). [1]: https://godbolt.org/z/h11183 # Versions * All GCC releases at least as far back as 4.7.1 (where I stopped looking). # System type * Debian (checked GCC 10.2.1) * Compiler Explorer (checked all other reported versions). # Options given to GCC `g++ -save-temps nullptr-relop.cpp -c -std=c++20`
[Bug c++/99374] New: C++17/20 mode fails to recognise pointer-to-member functions of incomplete types in conditional expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99374 Bug ID: 99374 Summary: C++17/20 mode fails to recognise pointer-to-member functions of incomplete types in conditional expression Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: cjdb.ns at gmail dot com Target Milestone: --- Created attachment 50296 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50296&action=edit Failure with -std=c++17 GCC seems to be unable to handle pointer-to-member functions of incomplete types in conditional expressions. The following works on both Clang and MSVC, and some invocations of GCC. ``` struct S; using F1 = int (S::*)(); using F2 = int (S::*)() noexcept; auto v = true ? F1() : F2(); auto w = true ? F2() : F1(); ``` This appears to work if `-std=c++14`, but not `-std=c++17` or `-std=c++20` for GCC versions >= 7. GCC < 7 doesn't have a problem compiling even in C++17 mode. # Versions * All GCC releases from 7.1.0 through trunk. # System type * Ubuntu 18.04 (checked GCC 10.1) * Ubuntu 20.04 on WSL2 (checked GCC 10.2) * Debian (checked GCC 10.2.1) * Compiler Explorer (checked all other reported versions). # Options given to GCC `g++ -save-temps fail-17.cpp -c -std=c++17` # Diagnostic ``` fail-17.cpp:5:27: error: could not convert ‘((int (S::*)() noexcept)0)’ from ‘int (S::*)() noexcept’ to ‘int (S::*)()’ 5 | auto v = true ? F1() : F2(); | ^ | | | int (S::*)() noexcept fail-17.cpp:6:27: error: could not convert ‘((int (S::*)() noexcept)0)’ from ‘int (S::*)() noexcept’ to ‘int (S::*)()’ 6 | auto w = true ? F2() : F1(); | ^ | | | int (S::*)() noexcept ```
