https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79593
--- Comment #4 from Katsunori Kumatani <katsunori.kumatani at gmail dot com> --- I forgot to mention that in the particular above example, it is obvious the "fstp" is useless. If you remove the "fld st(0)" and then the 'p' from the fstp, you end up with "fst st(0)" which is basically a no-op. My reasoning was for different cases, though, where one might need the fst but not the fld.