[PATCH, fortran] [13/14/15/16 Regression][Ope nACC] '!$acc ... attach(scalar)' – ICE 'unexpe cted pointer mapping node'

From 5fae5d7c4e9c25d18c52a14d5ff8779030908ff5 Mon Sep 17 00:00:00 2001
From: Christopher Albert <[email protected]>
Date: Tue, 10 Mar 2026 23:26:13 +0100
Subject: [PATCH] fortran: Fix scalar OpenACC attach/detach lowering [PR120723]

Lower bare scalar OpenACC attach/detach clauses as direct attach operations instead of emitting standalone pointer-mapping nodes.

	PR fortran/120723

gcc/fortran/ChangeLog:

	* trans-openmp.cc (gfc_trans_omp_clauses): Handle bare scalar
	OpenACC attach/detach clauses without pointer-mapping nodes.

gcc/testsuite/ChangeLog:

	* gfortran.dg/goacc/pr120723.f90: New test.

Signed-off-by: Christopher Albert <[email protected]>
---
 gcc/fortran/trans-openmp.cc                  | 20 ++++++++++++++++++++
 gcc/testsuite/gfortran.dg/goacc/pr120723.f90 | 20 ++++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/goacc/pr120723.f90

diff --git a/gcc/fortran/trans-openmp.cc b/gcc/fortran/trans-openmp.cc
index 3dd4cf272e5..660d56385bb 100644
--- a/gcc/fortran/trans-openmp.cc
+++ b/gcc/fortran/trans-openmp.cc
@@ -4400,6 +4400,14 @@ gfc_trans_omp_clauses (stmtblock_t *block, gfc_omp_clauses *clauses,
 				       != BT_VOID))))
 		    {
 		      tree orig_decl = decl;
+		      bool bare_attach_detach
+			= (openacc
+			   && (n->u.map.op == OMP_MAP_ATTACH
+			       || n->u.map.op == OMP_MAP_DETACH)
+			   && !GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (decl))
+			   && !(POINTER_TYPE_P (TREE_TYPE (decl))
+				&& GFC_DESCRIPTOR_TYPE_P (TREE_TYPE
+							  (TREE_TYPE (decl)))));
 
 		      /* For nonallocatable, nonpointer arrays, a temporary
 			 variable is generated, but this one is only defined if
@@ -4424,6 +4432,18 @@ gfc_trans_omp_clauses (stmtblock_t *block, gfc_omp_clauses *clauses,
 							     cond, tmp,
 							     NULL_TREE));
 			}
+		      /* Bare OpenACC attach/detach on scalar pointer-like
+			 variables wants a single attach operation on the
+			 pointer itself, not a standalone pointer-mapping
+			 node.  Component and descriptor cases have dedicated
+			 handling below; this covers the plain scalar path.  */
+		      if (bare_attach_detach)
+			{
+			  decl = build_fold_indirect_ref (decl);
+			  OMP_CLAUSE_DECL (node) = build_fold_addr_expr (decl);
+			  OMP_CLAUSE_SIZE (node) = size_zero_node;
+			  goto finalize_map_clause;
+			}
 		      /* For descriptor types, the unmapping happens below.  */
 		      if (op != EXEC_OMP_TARGET_EXIT_DATA
 			  || !GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (decl)))
diff --git a/gcc/testsuite/gfortran.dg/goacc/pr120723.f90 b/gcc/testsuite/gfortran.dg/goacc/pr120723.f90
new file mode 100644
index 00000000000..606dcbd4f2f
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/goacc/pr120723.f90
@@ -0,0 +1,20 @@
+! { dg-do compile }
+! { dg-additional-options "-fdump-tree-original" }
+!
+! PR fortran/120723 - scalar OpenACC attach/detach must not lower through a
+! standalone pointer-mapping node.
+
+implicit none (type, external)
+integer, pointer :: a, b(:)
+integer, allocatable :: c, d(:)
+
+! Scalar pointer and allocatable items used to ICE here.
+!$acc enter data attach(a, c)
+!$acc enter data attach(b, d)
+!$acc exit data detach(a, c)
+!$acc exit data detach(b, d)
+
+! { dg-final { scan-tree-dump-times "(?n)#pragma acc enter data map\\(attach:a \\\[bias: 0\\\]\\) map\\(attach:c \\\[bias: 0\\\]\\);$" 1 "original" } }
+! { dg-final { scan-tree-dump-times "(?n)#pragma acc exit data map\\(detach:a \\\[bias: 0\\\]\\) map\\(detach:c \\\[bias: 0\\\]\\);$" 1 "original" } }
+
+end
-- 
2.53.0