[Mlir-commits] [flang] [mlir] [OpenMP][flang] Lowering of OpenMP custom reductions to MLIR (PR #168417)

[Kareem Ergawy]

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@@ -3563,12 +3565,137 @@ genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
     TODO(converter.getCurrentLocation(), "OmpDeclareVariantDirective");
 }
 
+static bool
+processReductionCombiner(lower::AbstractConverter &converter,
+                         lower::SymMap &symTable,
+                         semantics::SemanticsContext &semaCtx,
+                         const parser::OmpReductionSpecifier &specifier,
+                         ReductionProcessor::GenCombinerCBTy &genCombinerCB) {
+  const auto &combinerExpression =
+      std::get<std::optional<parser::OmpCombinerExpression>>(specifier.t)
+          .value();
+  const parser::OmpStylizedInstance &combinerInstance =
+      combinerExpression.v.front();
+  const parser::OmpStylizedInstance::Instance &instance =
+      std::get<parser::OmpStylizedInstance::Instance>(combinerInstance.t);
+  if (const auto *as = std::get_if<parser::AssignmentStmt>(&instance.u)) {
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ergawy wrote:

How is the caller expected to behave in case there is no `AssignmentStmt`? Should we signal this as an error somehow? Or `assert`?

https://github.com/llvm/llvm-project/pull/168417