[Bug tree-optimization/97223] New: Failure to optimize comparison of char arithmetic to comparison

[gabravier at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97223

            Bug ID: 97223
           Summary: Failure to optimize comparison of char arithmetic to
                    comparison
           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(char x)
{
    return x < (char)(x + some_constant);
}

This (where `some-constant` is replaced by a constant expression) can be
optimized to `return x <= (CHAR_MAX - some_constant);`. This optimization is
done by LLVM, but not by GCC.