https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88097
Daniel Fruzynski <bugzi...@poradnik-webmastera.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |UNCONFIRMED
Resolution|INVALID |---
--- Comment #4 from Daniel Fruzynski <bugzi...@poradnik-webmastera.com> ---
Looks that there is one more issue here, ntohs is implemented with inline
assembly instead of __builtin_bswap16. When I tried to use this buildin gcc
started using movbe instruction when compiling with -O3 -mmovbe.
uint32_t test2(Test* ip)
{
return ((__builtin_bswap16(ip->Word1) << 16) |
__builtin_bswap16(ip->Word2));
}
test2(Test*):
movbe ax, WORD PTR [rdi]
movbe dx, WORD PTR [rdi+2]
sal eax, 16
movzx edx, dx
or eax, edx
ret
When I was logging this issue yesterday, bugzilla showed Bug 54733 as a
possible duplicate. Looks that gcc already has some similar kind of
optimization implemented. I suspect that after fixing system headers to use
__builtin_bswap* instead of inline assembly it would be possible to improve
this optimization further. I reopen this issue.
