On Tue, Aug 23, 2011 at 11:35:07AM +0200, Bernd Schmidt wrote:
> > cse_process_notes_1
> > perhaps could be changed for VOIDmode new_rtx to try to
> > simplify_replace_rtx it...
>
> Is this where the problem came from? Sounds like it's worth a try.
In this case, yes. But there are many other places all around the
compiler that need to disallow unary op with VOIDmode operand.
In cse.c alone e.g. fold_rtx (twice), in combine.c e.g. in do_SUBST,
subst, etc. Do we want to special case all those 7 unary ops there too?
Is it really worth it to save one subreg or truncate in the md patterns
for rarely used rtxes?
> Wasn't Richard S. working on a patch to give constants modes?
I don't think this is achievable for 4.7...
Jakub
