https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103534
Martin Sebor <msebor at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic Last reconfirmed| |2021-12-02 Ever confirmed|0 |1 Blocks| |88443 CC| |msebor at gcc dot gnu.org Status|UNCONFIRMED |NEW --- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> --- The warning is for the memcpy() call in BB 12 with _73 being in the reported excessive range: <bb 12> [local count: 172868773]: _209 = D.41961._M_dataplus._M_p; _103 = _69 + 16; __builtin_memcpy (_103, _209, _73); <<< 27->12 (T) _73 : long unsigned int [18446744073709551600, +INF] The range comes from BB 27: =========== BB 27 ============ Imports: _73 Exports: _73 _73 long unsigned int [0, 0][18446744073709551600, +INF] __size_74 const long unsigned int [0, 16] <bb 27> [local count: 523844769]: if (_73 != 0) goto <bb 12>; [33.00%] else goto <bb 13>; [67.00%] 27->12 (T) _73 : long unsigned int [18446744073709551600, +INF] 27->12 (T) __size_74 : const long unsigned int [0, 15] 27->13 (F) _73 : long unsigned int [0, 0] 27->13 (F) __size_74 : const long unsigned int [16, 16] The magic 16 most likely has to do with the small internal std::string buffer that's 16 bytes big. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443 [Bug 88443] [meta-bug] bogus/missing -Wstringop-overflow warnings