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From: "slyfox at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/103984] New: [12 regression] Possible maybe-uninitialized false positive on shaderc-2021.0 Date: Tue, 11 Jan 2022 22:18:29 +0000 [thread overview] Message-ID: <bug-103984-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103984 Bug ID: 103984 Summary: [12 regression] Possible maybe-uninitialized false positive on shaderc-2021.0 Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: slyfox at gcc dot gnu.org Target Milestone: --- Noticed new warning on shaderc-2021.0 which uses -Werror. Last week's gcc-12 snapshot did not flag it as a warning. Here is the extracted example: // $ cat glslc/src/main.cc #include <string> #include <vector> #include <cstring> struct string_piece { const char * begin_ = nullptr; const char * end_ = nullptr; std::string str() const { return std::string(begin_, end_); } string_piece(const char* string) : begin_(string), end_(string) { end_ += strlen(string); } string_piece(const string_piece& other) { begin_ = other.begin_; end_ = other.end_; } }; struct Z { std::string name; int stage; }; extern int to_stage(string_piece file_name); int main(int argc, char** argv) { std::vector<Z> input_files; const std::string current_entry_point_name("main"); const string_piece arg = argv[0]; input_files.emplace_back(Z{ arg.str(), // what is the lifetime of this temporary? to_stage(arg), // why does this constructor matter? }); return 0; } $ g++-12.0.0 -O1 -Wall -Werror -std=c++11 -o main.cc.o -c glslc/src/main.cc In file included from /<<NIX>>/gcc-12.0.0/include/c++/12.0.0/string:53, from glslc/src/main.cc:1: In member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::pointer std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_data() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]', inlined from 'bool std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_is_local() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /<<NIX>>/gcc-12.0.0/include/c++/12.0.0/bits/basic_string.h:275:23, inlined from 'void std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_dispose() [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /<<NIX>>/gcc-12.0.0/include/c++/12.0.0/bits/basic_string.h:286:18, inlined from 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::~basic_string() [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /<<NIX>>/gcc-12.0.0/include/c++/12.0.0/bits/basic_string.h:793:19, inlined from 'int main(int, char**)' at glslc/src/main.cc:35:1: /<<NIX>>/gcc-12.0.0/include/c++/12.0.0/bits/basic_string.h:235:28: error: '<unnamed>.Z::name.std::__cxx11::basic_string<char>::_M_dataplus.std::__cxx11::basic_string<char>::_Alloc_hider::_M_p' may be used uninitialized [-Werror=maybe-uninitialized] 235 | { return _M_dataplus._M_p; } | ^~~~ glslc/src/main.cc: In function 'int main(int, char**)': glslc/src/main.cc:32:3: note: '<anonymous>' declared here 32 | }); | ^ cc1plus: all warnings being treated as errors $ g++-12.0.0 -v Using built-in specs. COLLECT_GCC=/<<NIX>>/gcc-12.0.0/bin/g++ COLLECT_LTO_WRAPPER=/<<NIX>>/gcc-12.0.0/libexec/gcc/x86_64-unknown-linux-gnu/12.0.0/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: Thread model: posix Supported LTO compression algorithms: zlib gcc version 12.0.0 20220109 (experimental) (GCC)
next reply other threads:[~2022-01-11 22:18 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-11 22:18 slyfox at gcc dot gnu.org [this message] 2022-01-11 22:31 ` [Bug c++/103984] " pinskia at gcc dot gnu.org 2022-01-11 22:34 ` pinskia at gcc dot gnu.org 2022-01-12 7:39 ` rguenth at gcc dot gnu.org 2022-01-12 8:29 ` jakub at gcc dot gnu.org 2022-01-26 17:48 ` [Bug c++/103984] [12 regression] Possible maybe-uninitialized false positive on shaderc-2021.0 since r12-6329 jason at gcc dot gnu.org 2022-01-26 18:35 ` jason at gcc dot gnu.org 2022-01-26 19:03 ` jason at gcc dot gnu.org 2022-01-26 19:25 ` [Bug middle-end/103984] " jason at gcc dot gnu.org 2022-03-01 15:04 ` marxin at gcc dot gnu.org 2022-03-01 15:26 ` [Bug middle-end/103984] [12 regression] Possible maybe-uninitialized false positive on shaderc-2021.0 since r12-6329-g4f6bc28fc7dd86bd cvs-commit at gcc dot gnu.org 2022-03-15 14:22 ` jakub at gcc dot gnu.org 2022-03-15 15:06 ` jakub at gcc dot gnu.org 2022-03-15 15:16 ` jakub at gcc dot gnu.org 2022-03-15 15:55 ` jakub at gcc dot gnu.org 2022-03-15 16:55 ` jakub at gcc dot gnu.org 2022-03-15 18:00 ` jakub at gcc dot gnu.org 2022-03-16 8:47 ` jakub at gcc dot gnu.org 2022-03-16 8:58 ` jakub at gcc dot gnu.org 2022-03-17 8:26 ` cvs-commit at gcc dot gnu.org 2022-03-17 8:46 ` jakub at gcc dot gnu.org
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