[Bug target/53399] "*ffs" pattern generates wrong code with BMI enabled (for corner cases)

[hjl.tools at gmail dot com]

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

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> 2012-05-18 14:28:40 UTC ---
This should be ok since the 0 input operand is ignored.
If not, please find out why.