http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53399
H.J. Lu <hjl.tools at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|"*ffs" pattern generates |"*ffs" pattern generates |wrong code with BMI enabled |wrong code with BMI enabled |(for corner cases) | --- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> 2012-05-20 16:18:25 UTC --- BSF and tzcnt are different with zero input. BSF sets ZF with zero input and tzcnt set CF with zero input.