fortran: [PR121628]

fortran: [PR121628]

This patch fixes PR121628 by implementing proper deep copy semantics for
derived types containing recursive allocatable array components, in
compliance with Fortran 2018+ standards.

The original implementation would generate infinitely recursive code at
compile time when encountering self-referential derived types with
allocatable components (e.g., type(t) containing allocatable type(t)
arrays). This patch solves the problem by generating a runtime helper
function that performs element-wise deep copying, avoiding compile-time
recursion while maintaining correct assignment semantics.

The trans-intrinsic.cc change enhances handling of constant values in
coarray atomic operations to ensure temporary variables are created when
needed, avoiding invalid address-of-constant expressions.

gcc/fortran/ChangeLog:

	PR fortran/121628
	* trans-array.cc (get_copy_helper_function_type): New function to
	create function type for element copy helpers.
	(get_copy_helper_pointer_type): New function to create pointer type
	for element copy helpers.
	(generate_element_copy_wrapper): New function to generate runtime
	helper for element-wise deep copying of recursive types.
	(structure_alloc_comps): Detect recursive allocatable array
	components and use runtime helper instead of inline recursion.
	Add includes for cgraph.h and function.h.
	* trans-decl.cc (gfor_fndecl_cfi_deep_copy_array): New declaration
	for runtime deep copy helper.
	(gfc_build_builtin_function_decls): Initialize the runtime helper
	declaration.
	* trans-intrinsic.cc (conv_intrinsic_atomic_op): Enhance handling of
	constant values in coarray atomic operations by detecting and
	materializing address-of-constant expressions.
	* trans.h (gfor_fndecl_cfi_deep_copy_array): Add external declaration.

libgfortran/ChangeLog:

	PR fortran/121628
	* Makefile.am: Add runtime/deep_copy.c to source files.
	* Makefile.in: Regenerate.
	* gfortran.map: Export _gfortran_cfi_deep_copy_array symbol.
	* libgfortran.h: Add prototype for internal_deep_copy_array.
	* runtime/deep_copy.c: New file implementing runtime deep copy
	helper for recursive allocatable array components.

gcc/testsuite/ChangeLog:

	PR fortran/121628
	* gfortran.dg/alloc_comp_deep_copy_5.f90: New test for recursive
	allocatable array deep copy.
	* gfortran.dg/alloc_comp_deep_copy_6.f90: New test for multi-level
	recursive allocatable deep copy.
	* gfortran.dg/array_memcpy_2.f90: Fix test with proper allocation.

	Signed-off-by: Christopher Albert <albert@tugraz.at>