> On Mon, Jan 04, 2010 at 12:18:50PM +0100, Steven Bosscher wrote: > > > This optimization is done by the first RTL cse pass. I can't > understand > > > why it's not being done for your target. I guess this will need a > > > powerpc expert. > > > > Known bug, see http://gcc.gnu.org/PR22141 > > That's unrelated. PR22141 is about (lack of) merging of adjacent stores > of > constant values into memory, but there are no memory stores involved > here, > everything is in registers, so PR22141 patch will make zero difference > here. > > IMHO we really should have some late tree pass that converts adjacent > bitfield operations into integral operations on non-bitfields (likely > with > alias set of the whole containing aggregate), as at the RTL level many > cases > are simply too many instructions for combine etc. to optimize them > properly, > while at the tree level it could be simpler.
Ah. I take it that v2's optimisation was structured differently, as it does spot and take care of this case? ***************************************************************** This email has been checked by the altohiway Mailcontroller Service *****************************************************************
