[Bug tree-optimization/95836] New: Failure to remove strchr converted to bool with string literal when bit magic would be much more efficient (and sometimes smaller)

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95836

            Bug ID: 95836
           Summary: Failure to remove strchr converted to bool with string
                    literal when bit magic would be much more efficient
                    (and sometimes smaller)
           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 c)
{
    return strchr("1234567890", c);
}

This (and a lot of other similar strchr calls with string literals) can be
optimized to using a few bitwise operations (here, to something like `return
((unsigned)c < 64) & ((((uint64_t)1 << c) & 287948901175001089) != 0);`). This
transformation is done by LLVM, but not by GCC.