[PATCH, fortran] Fix OpenMP iterator depend lowering for component, arrays [PR102459]

From dcc53363931b63ae6f0f197b779c13fb8cd18d26 Mon Sep 17 00:00:00 2001
From: Christopher Albert <[email protected]>
Date: Tue, 10 Mar 2026 18:46:54 +0100
Subject: [PATCH] fortran: Fix OpenMP iterator depend lowering for component
 arrays [PR102459]

When lowering an OpenMP depend clause with an iterator expression such as
x(j)%a, the front end currently looks only at the first REF_ARRAY to
decide between scalar-reference lowering and array-descriptor lowering.
For x(j)%a that first ref is the scalar base element x(j), but the full
expression is still the rank-1 component array a.

As a result, the code calls gfc_conv_expr_reference on an array-valued
expression, which later reaches gfc_conv_scalarized_array_ref without a
scalarizer state and ICEs.

Fix this by choosing the lowering path from the rank of the full
expression.  Rank-zero expressions still use gfc_conv_expr_reference,
while array-valued expressions are lowered through gfc_conv_expr_descriptor.
Apply the same adjustment to the analogous depobj helper and add a
regression test for task depend clauses covering both x(j)%a and the
scalar control case x(j)%a(1).

gcc/fortran/ChangeLog:

	PR fortran/102459
	* trans-openmp.cc (gfc_trans_omp_clauses): Choose the scalar
	reference path from the full expression rank rather than the first
	array reference.
	(gfc_trans_omp_depobj): Likewise.

gcc/testsuite/ChangeLog:

	PR fortran/102459
	* gfortran.dg/pr102459.f90: New test.

Signed-off-by: Christopher Albert <[email protected]>
---
 gcc/fortran/trans-openmp.cc            |  8 ++++++--
 gcc/testsuite/gfortran.dg/pr102459.f90 | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr102459.f90

diff --git a/gcc/fortran/trans-openmp.cc b/gcc/fortran/trans-openmp.cc
index 3dd4cf272e5..7252bc123ee 100644
--- a/gcc/fortran/trans-openmp.cc
+++ b/gcc/fortran/trans-openmp.cc
@@ -4154,7 +4154,11 @@ gfc_trans_omp_clauses (stmtblock_t *block, gfc_omp_clauses *clauses,
 		{
 		  tree ptr;
 		  gfc_init_se (&se, NULL);
-		  if (n->expr->ref->u.ar.type == AR_ELEMENT)
+		  /* The first ref can be an element selection on the base
+		     object while the full expression still denotes an array,
+		     e.g. x(j)%a.  Pick the lowering path from the overall
+		     expression rank, not from the first REF_ARRAY.  */
+		  if (n->expr->rank == 0)
 		    {
 		      gfc_conv_expr_reference (&se, n->expr);
 		      ptr = se.expr;
@@ -7438,7 +7442,7 @@ gfc_trans_omp_depobj (gfc_code *code)
       else if (n->expr && n->expr->ref->u.ar.type != AR_FULL)
 	{
 	  gfc_init_se (&se, NULL);
-	  if (n->expr->ref->u.ar.type == AR_ELEMENT)
+	  if (n->expr->rank == 0)
 	    {
 	      gfc_conv_expr_reference (&se, n->expr);
 	      var = se.expr;
diff --git a/gcc/testsuite/gfortran.dg/pr102459.f90 b/gcc/testsuite/gfortran.dg/pr102459.f90
new file mode 100644
index 00000000000..c6b6c5eed63
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr102459.f90
@@ -0,0 +1,15 @@
+! { dg-do compile }
+! { dg-additional-options "-fopenmp" }
+
+program p
+  type t
+    integer :: a(2)
+  end type
+  type(t) :: x(8)
+
+  !$omp task depend (iterator(j=1:8), out:x(j)%a)
+  !$omp end task
+
+  !$omp task depend (iterator(j=1:8), out:x(j)%a(1))
+  !$omp end task
+end
-- 
2.53.0