[PATCH] D94604: [CodeGen] Allow parallel uses of a resource

[Andrea Di Biagio via Phabricator via llvm-commits]

andreadb added a comment.

I have only skimmed through this patch once, however I think that you can fix the problem in https://reviews.llvm.org/D94605 without introducing your new field `ResourceUses`.

The "problematic" resource is M7UnitVPort

  def M7UnitVPort  : ProcResource<2> { let BufferSize = 0; }

In your case, you want to allow the consumption of both resource units from a single write.
You can do that if you convert M7UnitVPort into a group (see example below)

  def M7UnitVPort0 : ProcResource<1> { let BufferSize = 0; }
  def M7UnitVPort1 : ProcResource<1> { let BufferSize = 0; }
  
  def M7UnitVPort : ProcResGroup<[M7UnitVPort0, M7UnitVPort1]>;

At that point, you simply enumerate the resource units in the list of consumed resources. So, something like this:

Example - before:

  def : WriteRes<WriteFPMAC64, [M7UnitVFP, M7UnitVPort, M7UnitVPort]>

Example - after:

  def : WriteRes<WriteFPMAC64, [M7UnitVFP, M7UnitVPort0, M7UnitVPort1]>

In conclusion, if the goal is to be able to do something like that, then I think the syntax is already expressive enough.
The obvious downside is that currently you need to declare multiple resources to do what you want to do.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D94604/new/

https://reviews.llvm.org/D94604