Uros Bizjak <ubiz...@gmail.com> writes: > On Tue, Jun 9, 2015 at 9:30 PM, Jakub Jelinek <ja...@redhat.com> wrote: >> On Tue, Jun 09, 2015 at 08:09:28PM +0200, Uros Bizjak wrote: >>> Please find attach a patch that takes your idea slightly further. We >>> find perhaps zero-extended UNSPEC_TP, and copy it for further use. At >>> its place, we simply slap const0_rtx. We know that address to >> >> Is that safe? I mean, the address, even if offsetable, can have some >> immediate already (seems e.g. the offsettable_memref_p predicate just checks >> you can plus_constant some small integer and be recognized again) and if you >> turn the %gs: into a const0_rtx, it would fail next decompose. >> And when you already have the PLUS which has UNSPEC_TP as one of its >> arguments, replacing that PLUS with the other argument is IMHO very easy. >> Perhaps you are right that there is no need to copy_rtx, supposedly >> the rtx shouldn't be shared with anything and thus can be modified in place. > > Hm, you are right. I was under impression that decompose_address can > handle multiple CONST_INT addends, which is unfortunatelly not the > case.
That's in some ways a feature though. I don't think we want to support multiple offsets, since that implies having more than one representation for the same address. Thanks, Richard
