[flang-commits] [flang] [flang] Handle assumed-type dummy arguments in ExtractDataRef (PR #169080)

[Peter Klausler via flang-commits]

https://github.com/klausler created https://github.com/llvm/llvm-project/pull/169080

Assumed-type dummy argument symbols s are never packaged in DataRefs since the only way they can be used in Fortran is by forwarded as actual arguments to other calls.  When an ActualArgument comprising a forwarded assumed-type dummy argument is presented to ExtractDataRef, it fails, because ExtractDataRef for ActualArgument only handles actual argument expressions (including variable references).  Add support for actual arguments that are assumed-type dummy arguments.

Fixes https://github.com/llvm/llvm-project/issues/168978.

>From 28947b2cebfc7eba531437462f6da1c65677da23 Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler at nvidia.com>
Date: Fri, 21 Nov 2025 10:24:58 -0800
Subject: [PATCH] [flang] Handle assumed-type dummy arguments in ExtractDataRef

Assumed-type dummy argument symbols s are never packaged in DataRefs
since the only way they can be used in Fortran is by forwarded as actual
arguments to other calls.  When an ActualArgument comprising a forwarded
assumed-type dummy argument is presented to ExtractDataRef, it fails,
because ExtractDataRef for ActualArgument only handles actual argument
expressions (including variable references).  Add support for actual
arguments that are assumed-type dummy arguments.

Fixes https://github.com/llvm/llvm-project/issues/168978.
---
 flang/lib/Evaluate/tools.cpp      | 6 +++++-
 flang/test/Evaluate/bug168978.f90 | 6 ++++++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 flang/test/Evaluate/bug168978.f90

diff --git a/flang/lib/Evaluate/tools.cpp b/flang/lib/Evaluate/tools.cpp
index 117b2249a9179..a0035ae330e35 100644
--- a/flang/lib/Evaluate/tools.cpp
+++ b/flang/lib/Evaluate/tools.cpp
@@ -63,7 +63,11 @@ Expr<SomeType> Parenthesize(Expr<SomeType> &&expr) {
 
 std::optional<DataRef> ExtractDataRef(
     const ActualArgument &arg, bool intoSubstring, bool intoComplexPart) {
-  return ExtractDataRef(arg.UnwrapExpr(), intoSubstring, intoComplexPart);
+  if (const Symbol *assumedType{arg.GetAssumedTypeDummy()}) {
+    return DataRef{*assumedType};
+  } else {
+    return ExtractDataRef(arg.UnwrapExpr(), intoSubstring, intoComplexPart);
+  }
 }
 
 std::optional<DataRef> ExtractSubstringBase(const Substring &substring) {
diff --git a/flang/test/Evaluate/bug168978.f90 b/flang/test/Evaluate/bug168978.f90
new file mode 100644
index 0000000000000..ffe77500aeba5
--- /dev/null
+++ b/flang/test/Evaluate/bug168978.f90
@@ -0,0 +1,6 @@
+!RUN: %flang_fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
+subroutine sub(dd)
+  type(*)::dd(..)
+  !CHECK: PRINT *, size(lbound(dd))
+  print *, size(lbound(dd)) ! do not fold
+end