[Bug tree-optimization/96897] New: Failure to optimize not+not+dec+and+not to add+or

[gabravier at gmail dot com]

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.