https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96897
Bug ID: 96897 Summary: Failure to optimize not+not+dec+and+not to add+or Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: gabravier at gmail dot com Target Milestone: --- int f(int x) { return ~(~x & (~x - 1)); } This can be optimized to `return (x + 1) | x;`. This transformation is done by LLVM, but not by GCC.