https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78964
Bug ID: 78964 Summary: gcc fails to detect pointless increment Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: dcb314 at hotmail dot com Target Milestone: --- Given the following C / C++ code: extern void g( int); void f( int n) { int m = 0; for (int i = 0; i < n; ++i) { g(i); ++m; } } gcc trunk dated 20161231 fails to detect that m can be safely removed: $ ~/gcc/results/bin/gcc -c -g -O2 -Wall -Wextra jan02.cc $ I think fixing this bug report will find about 100 bugs in the linux kernel.