[PATCH] D75837: Introduce std.execute_region op

[Uday Bondhugula via Phabricator via llvm-commits]

bondhugula added a comment.

> If you want these canonicalizations to apply immediately, you should just use implicit capture for all values (which is what you propose).

So we are actually on the same page as far as the benefits of implicit captures goes? I was under the impression that you were missing those, but you just want the option to use explicit captures on this when you really have such a use case -- but  then with the explicit captures comes the question of how the arguments obtain their values and you can't have custom behavior there because the lowering would need to know how exactly those arguments obtain those values or how operands bind to arguments, for eg. that there is a 1:1 match between its operands and arguments. And if there is a 1:1 match, we are back to the question why not just do a RAUW and eliminate those arguments in the first place? OTOH, if your arguments obtain values from operands or elsewhere in a more custom way, then the lowering would need to be aware of it in an unambiguous way, and you'd have to design/evaluate that. As @silvas mentions too, this still means it makes sense to start from the most restrictive form (only implicit captures), and evaluate an explicit capture option by first defining what exactly the capture argument semantics are for the use case, how it impacts the lowering, and mechanically, what the new syntax of the op would look like. (It is just two lines to knock off in the verifier if you want the op to take region arguments.)


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D75837/new/

https://reviews.llvm.org/D75837