> compiler stores the `c` to stack every time

The disassembly we looked at didn't do this, so it may just be certain compilers. Perhaps we can actually use the register keyword to help them out? :)


Here's a slightly altered one that doesn't require rescanning for the sake of the error message:

        Py_UCS4 c = 0, minc = strict ? 0x20 : 0x00;
        for (next = end; next < len; next++) {
            c = PyUnicode_READ(kind, buf, next);
            if (c == '"' || c == '\\' || c < minc) {
                break;
            }
        }
        if (c < minc) {
            raise_errmsg("Invalid control character at", pystr, next);
            goto bail;
        }