[flang-commits] [flang] [flang] allow rebox/embox of OPTIONAL (PR #194319)

[Tom Eccles via flang-commits]

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@@ -55,6 +57,40 @@ static void populateShift(llvm::SmallVectorImpl<mlir::Value> &vec,
   vec.append(shift.getOrigins().begin(), shift.getOrigins().end());
 }
 
+// Helper to emit embox/rebox for OPTIONAL input inside a block
+// guarded by a runtime presence check and to return an absent
+// box when the input is not present.
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tblah wrote:

Wouldn't that representation require us to conditionally limit speculation for any operation which reads from a box (`fir.box_addr`, `fir.box_dims`, etc)? If there was a real box containing a nullptr address then I think we only need to limit speculation on `fir.load` (which presumably is already the case).

https://github.com/llvm/llvm-project/pull/194319