On Wed, 22 Mar 2023 18:27:28 -0400 Sid Maxwell via Gcc <gcc@gcc.gnu.org> wrote:
> Is there anyone on the list with experience with the gcc 4.3 > codebase? I'm currently maintaining a fork of it, with a PDP10 code > generator. > > I've run into an issue involving the transformation of a movmemhi to a > single PDP10 instruction (an xblt, if you're curious). The > transformation appears to 'lose' its knowledge of being a store, > resulting in certain following stores being declared dead, and code > motion that shouldn't happen (e.g. a load moved before the xblt that > depends on the result of the xblt). > > I'm hoping to find someone who can help me diagnose the problem. We > want to use this instruction rather than the copy-word-loop currently > generated for struct assignments. I think we'd need a bit more info than that... what does the movmemhi instruction pattern look like, for example? Julian
