On Fri, May 20, 2016 at 08:54:39AM -0700, Andi Kleen wrote:
> I thought I had filed a bugzilla at some point, but can't
> find it right now. If you compare bitfield code
> compiled for Haswell on LLVM and GCC it is very visible
> how much worse gcc is.
We really need to lower bitfield operations (especially when there are
multiple adjacent ones) to integer arithmetics on the underlying
DECL_BIT_FIELD_REPRESENTATIVE fields somewhere in (late?) gimple and
perform some cleanups after it and only after that expand.
Jakub
