[Bug fortran/90578] Wrong code with LSHIFT and optimization

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90578

--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Compiling

print *, lshift(1,-1)
end

gives the following error

lshift.f90:1:16:

    1 | print *, lshift(1,-1)
      |                1
Error: Second argument of LSHIFT is negative at (1)

While

print *, ishft(2,-1)
end

gives

           1