[PATCH] D80358: [MLIR] Add RegionKindInterface

Fri Jun 19 01:34:53 PDT 2020

mehdi_amini added inline comments.

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Comment at: mlir/docs/LangRef.md:468

-A region is a CFG of MLIR [Blocks](#blocks). Regions serve to group semantically
-connected blocks, where the semantics is not imposed by the IR. Instead, the
-containing operation defines the semantics of the regions it contains. Regions
-do not have a name or an address, only the blocks contained in a region do.
-Regions are meaningless outside of the containing entity and have no type or
-attributes.
+A region is an ordered sequence of MLIR [Blocks](#blocks), commonly
+used to represent a Control-Flow Graph (CFG). Regions serve to group
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stephenneuendorffer wrote:
> mehdi_amini wrote:
> > I'm not sure why we're changing CFG into `ordered sequence` here, this seems under-specified
> How so?  The point of this is to show the structures that are important and that are the requirements on those structures, so I'm trying to define a region structurally separate from the CFG semantics.  What would you add to this, other than "it's a CFG?"
I see the structure as trivial: only the semantics is complex (i.e. reachability, control-flow, etc.).

So I'm not sure what's the point of long description of what could be shown with a few lines of grammar specification (or even 10 lines of C++).

Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80358/new/

https://reviews.llvm.org/D80358