[Bug rtl-optimization/55952] x86 FPU, unnecessary fxch instruction

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55952

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
Latest trunk gcc generates:

        flds    4(%esp)
        fldz
        fucomip %st(1), %st
        fstp    %st(0)
        fld1
        fchs
        fld1
        fcmovnbe        %st(1), %st
        fstp    %st(1)
        ret