[LLVMdev] Proposal: extended MDString syntax

Jakob Stoklund Olesen stoklund at 2pi.dk
Thu Jun 27 16:13:51 PDT 2013


On Jun 27, 2013, at 3:22 PM, Dan Gohman <dan433584 at gmail.com> wrote:

> On Thu, Jun 27, 2013 at 10:49 AM, Jakob Stoklund Olesen <stoklund at 2pi.dk> wrote:
> 
> > MI should be allowed to evolve into a proper self-contained IR that doesn’t depend on LLVM IR.
> 
> This is an interesting point. I tend to think of CodeGen as being an analysis of LLVM IR, and while it can diverge somewhat, the ways in which it diverges are usually constrained in some ways, and that leveraging information already available in LLVM IR was practical.

That has traditionally been the case.

> However, In a world where CodeGen is doing things like restructuring loops, this seems less practical.

I think that passes like LSR and vectorization really should be MI passes because they are so closely coupled with the subtarget. I could imagine some sort of symbiosis with the instruction selector as well.

This would require a version of MI with generic opcodes, a lot like a SelectionDAG looks before isel. (And an MI SCEV).

Thanks,
/jakob





More information about the llvm-dev mailing list