https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105164
Bug ID: 105164 Summary: new warning in clang, missing in gcc: -Wbitwise-instead-of-logical Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: dcb314 at hotmail dot com Target Milestone: --- For this C++ code: extern bool f1( int); extern void f3( int); void f2( int n) { if (!f1(n) & !f1( n + 1)) f3( n - 1); if (!f1(n) | !f1( n + 1)) f3( n + 1); } recent gcc trunk says not a lot: $ /home/dcb/gcc/results/bin/g++ -g -O2 -Wall -Wextra -pedantic -c jul01a.cc $ However, new clang-14 says: $ clang++ -g -O2 -Wall -Wextra -pedantic -c jul01a.cc jul01a.cc:8:6: warning: use of bitwise '&' with boolean operands [-Wbitwise-instead-of-logical] if (!f1(n) & !f1( n + 1)) ^~~~~~~~~~~~~~~~~~~~ && jul01a.cc:8:6: note: cast one or both operands to int to silence this warning jul01a.cc:11:6: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical] if (!f1(n) | !f1( n + 1)) ^~~~~~~~~~~~~~~~~~~~ || jul01a.cc:11:6: note: cast one or both operands to int to silence this warning 2 warnings generated. $ Static analyser cppcheck also finds the problem: $ /home/dcb/cppcheck/trunk.git/cppcheck --enable=all jul01a.cc jul01a.cc:8:13: style: Boolean result is used in bitwise operation. Clarify expression with parentheses. [clarifyCondition] if (!f1(n) & !f1( n + 1)) ^ jul01a.cc:11:13: style: Boolean result is used in bitwise operation. Clarify expression with parentheses. [clarifyCondition] if (!f1(n) | !f1( n + 1)) ^ jul01a.cc:6:0: style: The function 'f2' is never used. [unusedFunction] ^