1 files changed, 32 insertions, 0 deletions
diff --git a/gcc/testsuite/gfortran.dg/intrinsic_optional_char_arg_1.f90 b/gcc/testsuite/gfortran.dg/intrinsic_optional_char_arg_1.f90
new file mode 100644
index 000000000..3215f43fa
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/intrinsic_optional_char_arg_1.f90
@@ -0,0 +1,32 @@
+! { dg-do compile }
+! { dg-options "-fdump-tree-original" }
+
+! PR fortran/36403
+! Check that string lengths of optional arguments are added to the library-call
+! even if those arguments are missing.
+
+PROGRAM main
+  IMPLICIT NONE
+
+  CHARACTER(len=1) :: vect(4)
+  CHARACTER(len=1) :: matrix(2, 2)
+
+  matrix(1, 1) = ""
+  matrix(2, 1) = "a"
+  matrix(1, 2) = "b"
+  matrix(2, 2) = ""
+  vect = (/ "w", "x", "y", "z" /)
+
+  ! Call the affected intrinsics
+  vect = EOSHIFT (vect, 2)
+  vect = PACK (matrix, matrix /= "")
+  matrix = RESHAPE (vect, (/ 2, 2 /))
+
+END PROGRAM main
+
+! All library function should be called with *two* trailing arguments "1" for
+! the string lengths of both the main array and the optional argument:
+! { dg-final { scan-tree-dump "_eoshift\[0-9_\]+char \\(\[&a-zA-Z0-9._, \]+, 1, 0\\)" "original" } }
+! { dg-final { scan-tree-dump "_reshape\[0-9_\]+char \\(\[&a-zA-Z0-9._, \]+, 1, 0\\)" "original" } }
+! { dg-final { scan-tree-dump "_pack\[0-9_\]+char \\(\[&a-zA-Z0-9._, \]+, 1, 0\\)" "original" } }
+! { dg-final { cleanup-tree-dump "original" } }