[flang-commits] [flang] [Flang] add support for collapsed io calls for implicit do loops (PR #212646)

[Jason Van Beusekom via flang-commits]

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@@ -701,6 +701,244 @@ static mlir::func::FuncOp getOutputFunc(mlir::Location loc,
                                                                    builder);
 }
 
+/// Return the evaluate expression of a non-implied-do io item, or nullptr if
+/// the item is itself an io-implied-do.
+static const Fortran::lower::SomeExpr *
+getIoItemLeafExpr(const Fortran::parser::OutputItem &item) {
+  if (const auto *parserExpr = std::get_if<Fortran::parser::Expr>(&item.u))
+    return Fortran::semantics::GetExpr(*parserExpr);
+  return nullptr;
+}
+static const Fortran::lower::SomeExpr *
+getIoItemLeafExpr(const Fortran::parser::InputItem &item) {
+  if (const auto *var = std::get_if<Fortran::parser::Variable>(&item.u))
+    return Fortran::semantics::GetExpr(*var);
+  return nullptr;
+}
+
+template <typename A>
+static bool ioExprReferencesSymbol(const A &expr,
+                                   const Fortran::semantics::Symbol &sym) {
+  const Fortran::semantics::Symbol &ultimate = sym.GetUltimate();
+  for (const Fortran::semantics::SymbolRef &ref :
+       Fortran::evaluate::CollectSymbols(expr)) {
+    if (&ref->GetUltimate() == &ultimate)
+      return true;
+  }
+  return false;
+}
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Jason-Van-Beusekom wrote:

In https://github.com/llvm/llvm-project/pull/212646/commits/7d7669f1398a9d2eb4ae5afa7ae784895fc2bbde I added guards to fallback on the provided cases, are there any other cases that concern you?

https://github.com/llvm/llvm-project/pull/212646