http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60788
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
LZCNT is encoded as F3 BSR:
0: f3 0f bd c0 lzcnt %eax,%eax
4: 0f bd c0 bsr %eax,%eax
Since your processor doesn't support LZCNT, F3 prefix is ignored
and f3 0f bd c0 is treated as BSR. Before you use LZCNT, you need
to check if your processor support it or not.
