[Bug middle-end/104081] Variable optimized out despite -Og

[matthias at urlichs dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104081

--- Comment #3 from Matthias Urlichs <matthias at urlichs dot de> ---
Sure.

gcc -Og -g -std=c++17 -lstdc++ /tmp/test.cpp


#include <string_view>
#include <string>

void throw_invalid(const char *a, std::string_view b) {
    (void)a; (void)b;
    throw;
}

int64_t str_atoi(std::string_view data)
{
    const std::string_view odata = data;

    int64_t val = 0;
    bool neg;

    if(data.length() == 0)
        throw_invalid("empty",odata);
    neg = data.front() == '-';
    if(neg) {
        data.remove_prefix(1);
        if(data.length() == 0)
            throw_invalid("empty",data);
    }
    for (const auto& c : data) {
        if (c < '0' || '9' < c)
            throw_invalid("not a number",odata);
        val = val*10 + c-'0';
    }
    if(neg)
        val = -val;
    return val;
}

int main() {
    volatile int x =  str_atoi("nope");
}