Fortran: fix ALLOCATE with SOURCE=, zero-length character [PR83865]

gcc/fortran/ChangeLog:

	PR fortran/83865
	* trans-stmt.cc (gfc_trans_allocate): Restrict special case for
	source-expression with zero-length character to rank 0, so that
	the array shape is not discarded.

gcc/testsuite/ChangeLog:

	PR fortran/83865
	* gfortran.dg/allocate_with_source_32.f90: New test.

diff --git a/gcc/fortran/trans-stmt.cc b/gcc/fortran/trans-stmt.cc
index 9b497d6bdc60e52a87d719083d70453eae0e9007..93b633e212e49dd9a41c5de2928c7fc020f7a3f6 100644 (file)
--- a/gcc/fortran/trans-stmt.cc
+++ b/gcc/fortran/trans-stmt.cc
@@ -6449,8 +6449,9 @@ gfc_trans_allocate (gfc_code * code, gfc_omp_namelist *omp_allocate)
       else
        gfc_add_block_to_block (&post, &se.post);
 
-      /* Special case when string in expr3 is zero.  */
+      /* Special case when string in expr3 is scalar and has length zero.  */
       if (code->expr3->ts.type == BT_CHARACTER
+         && code->expr3->rank == 0
          && integer_zerop (se.string_length))
        {
          gfc_init_se (&se, NULL);

diff --git a/gcc/testsuite/gfortran.dg/allocate_with_source_32.f90 b/gcc/testsuite/gfortran.dg/allocate_with_source_32.f90
new file mode 100644 (file)
index 0000000..4a9bd46
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/allocate_with_source_32.f90
@@ -0,0 +1,33 @@
+! { dg-do run }
+!
+! PR fortran/83865
+!
+! Test ALLOCATE with SOURCE= of deferred length character, where
+! the source-expression is an array of character with length 0.
+
+program p
+  implicit none
+  character(:), allocatable :: z(:)
+  character(1) :: cc(4) = ""
+  allocate (z, source=[''])
+  if (len (z) /= 0 .or. size (z) /= 1) stop 1
+  deallocate (z)
+  allocate (z, source=['',''])
+  if (len (z) /= 0 .or. size (z) /= 2) stop 2
+  deallocate (z)
+  allocate (z, source=[ character(0) :: 'a','b','c'])
+  if (len (z) /= 0 .or. size (z) /= 3) stop 3
+  deallocate (z)
+  allocate (z, source=[ character(0) :: cc ])
+  if (len (z) /= 0 .or. size (z) /= 4) stop 4
+  deallocate (z)
+  associate (x => f())
+    if (len (x) /= 0 .or. size (x) /= 1) stop 5
+    if (x(1) /= '') stop 6
+  end associate
+contains
+  function f() result(z)
+    character(:), allocatable :: z(:)
+    allocate (z, source=[''])
+  end function f
+end