On 12/8/18 5:14 AM, Richard Sandiford wrote: > Andrew Stubbs <a...@codesourcery.com> writes: >> On 21/11/2018 00:47, Jeff Law wrote: >>> This seems like a really gross hack and sets an expectation that >>> generating registers in the target after IRA has started is OK. It is >>> not OK. THe fact that this works is, IMHO, likely an accident. >> >> What's the proper test for this? Neither lra_in_progress nor >> reload_in_progress is set here, and can_create_pseudos returns true. >> >> The patterns have the ability to not generate registers, but they don't >> know not to. >> >> Richard Sandiford has stated that it should be OK, but perhaps the other >> architectures also work by accident? > > Yeah, my understanding was that targets could create new registers here, > and I thought targets did in some situations. But that's also why I'm > suspicious of the patch. If GCN is doing something valid and IRA isn't > coping, then the patch seems to be fixing the problem in the wrong place. IRA/LRA can create new pseudos internally. What I'm much less sure about is whether or not the target can create them. WHen IRA/LRA creates one internally it has the chance to update the various internal structures it needs. That can't happen with a pseudo created by the target this late. Vlad would know for sure.
jeff
