[Bug tree-optimization/95527] New: Failure to optimize __builtin_ffs == 0

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95527

            Bug ID: 95527
           Summary: Failure to optimize __builtin_ffs == 0
           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: ---

bool f(int x)
{
    return __builtin_ffs(x) == 0;
}

This can be optimized to `x == 0`. This transformation is done by LLVM, but not
by GCC.