[Bug middle-end/90693] New: Missing popcount simplifications

[wilco at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90693

            Bug ID: 90693
           Summary: Missing popcount simplifications
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: wilco at gcc dot gnu.org
  Target Milestone: ---

While GCC optimizes __builtin_popcount (x) != 0 into x != 0, we can also
optimize __builtin_popcount (x) == 1 into x == (x & -x), and __builtin_popcount
(x) > 1 into (x & (x-1)) != 0.