https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113186
Bug ID: 113186 Summary: [13/14 Regression] `(a^c) & (a^!c)` is not optimized to 0 for bool Product: gcc Version: 14.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: tree-optimization Assignee: pinskia at gcc dot gnu.org Reporter: pinskia at gcc dot gnu.org Target Milestone: --- Take: ``` bool f(bool a, bool c) { bool b = (a^c); bool d = (a^!c); return b & d; } ``` This should optimize to 0 but does not since GCC 13. With the C++ front-end, I suspect since r13-1779-g375668e0508fbe . With the C front-end, it started on the trunk. For C have in forwprop1: b_7 = a_5(D) ^ c_6(D); _11 = a_5(D) ^ c_6(D); _12 = a_5(D) == c_6(D); _13 = b_7 & _12; For C++ we have (at -O1): b_7 = a_5(D) != c_6(D); _1 = ~c_6(D); d_8 = _1 != a_5(D); _11 = b_7 & d_8; For C++ at -O2 in forwprop2, we have similar as what with the C front-end.