[llvm-branch-commits] [flang] [mlir] [flang][OpenMP] Lower target in_reduction for host fallback (PR #199967)

[Sairudra More via llvm-branch-commits]

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@@ -3108,6 +3113,58 @@ genTargetOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
           Object{const_cast<semantics::Symbol *>(&sym), std::nullopt});
     }
   };
+  // OpenMP requires `in_reduction` list items on `target` to be implicitly
+  // data-mapped. The MLIR -> LLVM IR translation passes the mapped pointer
+  // as the `orig` argument of `__kmpc_task_reduction_get_th_data`, so the
+  // map must be address-preserving regardless of the scalar default capture
+  // (which would otherwise be ByCopy for small scalars and break the
+  // runtime lookup against the enclosing taskgroup's task_reduction
+  // descriptor). Emit these maps before the generic implicit-map walk so
+  // that walk treats the symbols as already mapped via
+  // `isDuplicateMappedSymbol` and does not downgrade them to ByCopy.
+  auto captureInReductionImplicitMap = [&](const semantics::Symbol &sym) {
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Saieiei wrote:

Refactored it to reuse `captureImplicitMap(..., forceAddressPreserving)`

https://github.com/llvm/llvm-project/pull/199967