public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug c++/105424] New: Bogus -Wstringop-overread with non-overread condition @ 2022-04-28 13:42 byteslice at airmail dot cc 2022-04-28 20:41 ` [Bug middle-end/105424] " pinskia at gcc dot gnu.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: byteslice at airmail dot cc @ 2022-04-28 13:42 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105424 Bug ID: 105424 Summary: Bogus -Wstringop-overread with non-overread condition Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: byteslice at airmail dot cc Target Milestone: --- Created attachment 52897 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52897&action=edit Cvised example On gcc 12.0.1 20220413 (Fedora 36 Beta), with c++ -std=c++20 -O1 -Werror=stringop-overread, the attachment fails to compile, with the following message: In function 'void boost::memmove(I, F) [with I = move_iterator<int*>; F = int]', inlined from 'F boost::uninitialized_copy_alloc(Allocator, I, F) [with Allocator = vector_alloc_holder; I = move_iterator<int*>; F = int]' at <source>:67:10, inlined from 'void boost::vector::priv_uninitialized_construct_at_end(InpIt, InpIt) [with InpIt = boost::move_iterator<int*>]' at <source>:91:45, inlined from 'void boost::vector::assign(FwdIt, FwdIt) [with FwdIt = boost::move_iterator<int*>]' at <source>:87:42, inlined from 'boost::small_vector::small_vector(boost::small_vector&&)' at <source>:106:11, inlined from 'Stack::Stack(Stack&&)' at <source>:113:8, inlined from 'pair<_T2>::pair(_U1, _U2) [with _U1 = int; _U2 = Stack; _T2 = Stack]' at <source>:5:24, inlined from 'pair<Stack> Stack::Pop() const' at <source>:118:67: <source>:63:14: error: 'void* memmove(void*, const void*, long unsigned int)' reading 9 or more bytes from a region of size 4 [-Werror=stringop-overread] 63 | ::memmove(dest_raw, beg_raw, n); | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~ <source>: In member function 'pair<Stack> Stack::Pop() const': <source>:103:9: note: source object '__trans_tmp_4' of size 4 103 | int __trans_tmp_4; | ^~~~~~~~~~~~~ cc1plus: some warnings being treated as errors Compiler returned: 1 This warning is bogus because the memmove is guarded by a condition that prevents the size from being more than 4. The bogus warning does not appear in older versions of GCC. Adding -fno-inline to options allows compilation to succeed. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/105424] Bogus -Wstringop-overread with non-overread condition 2022-04-28 13:42 [Bug c++/105424] New: Bogus -Wstringop-overread with non-overread condition byteslice at airmail dot cc @ 2022-04-28 20:41 ` pinskia at gcc dot gnu.org 2022-04-28 20:59 ` byteslice at airmail dot cc ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-04-28 20:41 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105424 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |WAITING Ever confirmed|0 |1 Last reconfirmed| |2022-04-28 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- > long n(end_raw - beg_raw); > if (n < 4) This means n could be negative which then converted to unsigned would be a large #. The code here is reduced too much though: value_type *dest_raw, *beg_raw = movelib::iterator_to_raw_pointer(f), *end_raw = 0; So basically you have (long)(beg_raw) < 4. Which might be true if the upper bit is set. Please attach the original preprocessed source as I have shown it was reduced too much. Plus I suspect adding a check for "n >= 0" will fix the warning too. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/105424] Bogus -Wstringop-overread with non-overread condition 2022-04-28 13:42 [Bug c++/105424] New: Bogus -Wstringop-overread with non-overread condition byteslice at airmail dot cc 2022-04-28 20:41 ` [Bug middle-end/105424] " pinskia at gcc dot gnu.org @ 2022-04-28 20:59 ` byteslice at airmail dot cc 2022-04-28 21:03 ` byteslice at airmail dot cc 2022-04-28 21:36 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: byteslice at airmail dot cc @ 2022-04-28 20:59 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105424 Liam White <byteslice at airmail dot cc> changed: What |Removed |Added ---------------------------------------------------------------------------- Attachment #52897|0 |1 is obsolete| | --- Comment #2 from Liam White <byteslice at airmail dot cc> --- Created attachment 52901 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52901&action=edit Preprocessed source ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/105424] Bogus -Wstringop-overread with non-overread condition 2022-04-28 13:42 [Bug c++/105424] New: Bogus -Wstringop-overread with non-overread condition byteslice at airmail dot cc 2022-04-28 20:41 ` [Bug middle-end/105424] " pinskia at gcc dot gnu.org 2022-04-28 20:59 ` byteslice at airmail dot cc @ 2022-04-28 21:03 ` byteslice at airmail dot cc 2022-04-28 21:36 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: byteslice at airmail dot cc @ 2022-04-28 21:03 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105424 --- Comment #3 from Liam White <byteslice at airmail dot cc> --- Compile with c++ -std=gnu++20 -O1 -Werror=stringop-overread to reproduce. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/105424] Bogus -Wstringop-overread with non-overread condition 2022-04-28 13:42 [Bug c++/105424] New: Bogus -Wstringop-overread with non-overread condition byteslice at airmail dot cc ` (2 preceding siblings ...) 2022-04-28 21:03 ` byteslice at airmail dot cc @ 2022-04-28 21:36 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-04-28 21:36 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105424 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|WAITING |UNCONFIRMED Ever confirmed|1 |0 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-04-28 21:36 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-04-28 13:42 [Bug c++/105424] New: Bogus -Wstringop-overread with non-overread condition byteslice at airmail dot cc 2022-04-28 20:41 ` [Bug middle-end/105424] " pinskia at gcc dot gnu.org 2022-04-28 20:59 ` byteslice at airmail dot cc 2022-04-28 21:03 ` byteslice at airmail dot cc 2022-04-28 21:36 ` pinskia at gcc dot gnu.org
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).