[Bug target/53399] "*ffs" pattern generates wrong code with BMI enabled

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53399

--- Comment #9 from H.J. Lu <hjl.tools at gmail dot com> 2012-05-20 16:24:13 
UTC ---
We can't use tzcnt in the current ffs patterns.
We should add a CCC variant for ffs patterns with
tzcnt.