[Bug c++/93921] New: -Os generates much bigger code than -O{1,2,3,fast} for std::string::size

[bsnoksru at cisco dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93921

            Bug ID: 93921
           Summary: -Os generates much bigger code than -O{1,2,3,fast} for
                    std::string::size
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bsnoksru at cisco dot com
  Target Milestone: ---

Testing with the following code-fragment 

#include <string>
#include <string_view>

int foo() {
    using namespace std::literals;
    return "asdf"s.size();
}

int bar() {
    using namespace std::string_view_literals;
    return "asdf"sv.size();
}

using g++ from `trunk` (as reported by godbolt), with flags "--std=c++17" and
different optimiziation levels show that the string-view size gets inlined to a
constant for all relevant optimization levels, while the string-size code gets
inflated when optimizing for size.