[Bug tree-optimization/96779] New: Failure to optimize comparison of negative version of self

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96779

            Bug ID: 96779
           Summary: Failure to optimize comparison of negative version of
                    self
           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 a)
{
    return -a == a;
}

This can be optimized to `return !a;`. This transformation is done by LLVM, but
not by GCC.