[flang-commits] [flang] [Flang][OpenMP] Fix crash and IR errors for user-defined reduction on allocatable variables (PR #186765)

[via flang-commits]

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@@ -803,6 +804,185 @@ bool ReductionProcessor::processReductionArguments(
                          &redOperator.u)) {
         if (!ReductionProcessor::supportedIntrinsicProcReduction(
                 *reductionIntrinsic)) {
+          if (isByRef) {
+            // create a new declare_reduction for the boxed type, reusing
+            // the existing init and combiner
+            semantics::Symbol *sym = reductionIntrinsic->v.sym();
+            llvm::StringRef baseName = {sym->name().begin(),
+                                        sym->name().size()};
+            mlir::ModuleOp module = builder.getModule();
+            auto existingDecl = module.lookupSymbol<OpType>(baseName);
+            if (!existingDecl) {
+              TODO(currentLocation,
+                   "User-defined reductions on allocatable or pointer "
+                   "variables: cannot find base reduction declaration");
+            }
+
+            std::string byrefName = getReductionName(
+                baseName, builder.getKindMap(), redType, isByRef);
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MattPD wrote:

Verified: the boxed op uses `getScopedUserReductionName` and its name resolves correctly, and a cross-module allocatable case lowers and runs correctly. Thanks for coordinating on this.

https://github.com/llvm/llvm-project/pull/186765