[flang-commits] [flang] [Flang] Add partial support for lowering procedure pointer assignment. (PR #70461)

[Daniel Chen via flang-commits]

================
@@ -3224,8 +3224,13 @@ class FirConverter : public Fortran::lower::AbstractConverter {
       mlir::Location loc, const Fortran::evaluate::Assignment &assign,
       const Fortran::evaluate::Assignment::BoundsSpec &lbExprs) {
     Fortran::lower::StatementContext stmtCtx;
-    if (Fortran::evaluate::IsProcedure(assign.rhs))
-      TODO(loc, "procedure pointer assignment");
+
+    if (Fortran::evaluate::IsProcedure(assign.rhs)) {
+      auto lhs{fir::getBase(genExprAddr(assign.lhs, stmtCtx, &loc))};
+      auto rhs{fir::getBase(genExprAddr(assign.rhs, stmtCtx, &loc))};
----------------
DanielCChen wrote:

I adopted your suggestion to have
```
    if (Fortran::evaluate::IsProcedurePointerTarget(assign.rhs)) {
      hlfir::Entity lhs = Fortran::lower::convertExprToHLFIR(
          loc, *this, assign.lhs, localSymbols, stmtCtx);
      hlfir::Entity rhs = Fortran::lower::convertExprToHLFIR(
          loc, *this, assign.rhs, localSymbols, stmtCtx);
      rhs = hlfir::derefPointersAndAllocatables(loc, *builder, rhs);
      builder->createStoreWithConvert(loc, rhs, lhs);
      return;
    }
    ```
    
    I ran into the following issue when do `pptr => foo()` where `foo` returns a procedure pointer.
    ```
    flang/lib/Lower/ConvertExprToHLFIR.cpp:1428: not yet implemented: lowering ProcRef to HLFIR
    ```
    Is lowering ProcRef being worked on?

https://github.com/llvm/llvm-project/pull/70461