https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81664
--- Comment #2 from Daniel Fruzynski <bugzi...@poradnik-webmastera.com> ---
So there is another problem here: for some reason both mentioned gcc versions
accepts -mmovbe and -mno-movbe options. If movbe is not supported, gcc should
complain that these options are unrecognized.
I also checked generated assembly code and there are no movbe instruction
there. However I noticed that gcc 4.8.5 on Redhat 7 generates different code
when -mmovbe is used - it adds extra instruction marked below with ***.
_Z11ntohl_movbel:
.LFB6:
.cfi_startproc
movl %edi, %eax
bswap %eax
movl %eax, %eax ***
ret
.cfi_endproc
