From 20da56165273c8814b3c53e6d71549ba6a37e0cd Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Sat, 13 Jan 2024 22:00:21 +0100
Subject: [PATCH] Fortran: intrinsic ISHFTC and missing optional argument SIZE
 [PR67277]

gcc/fortran/ChangeLog:

	PR fortran/67277
	* trans-intrinsic.cc (gfc_conv_intrinsic_ishftc): Handle optional
	dummy argument for SIZE passed to ISHFTC.  Set default value to
	BIT_SIZE(I) when missing.

gcc/testsuite/ChangeLog:

	PR fortran/67277
	* gfortran.dg/ishftc_optional_size_1.f90: New test.
---
 gcc/fortran/trans-intrinsic.cc                | 14 +++
 .../gfortran.dg/ishftc_optional_size_1.f90    | 97 +++++++++++++++++++
 2 files changed, 111 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/ishftc_optional_size_1.f90

diff --git a/gcc/fortran/trans-intrinsic.cc b/gcc/fortran/trans-intrinsic.cc
index 74139262657..0468dfae2b1 100644
--- a/gcc/fortran/trans-intrinsic.cc
+++ b/gcc/fortran/trans-intrinsic.cc
@@ -6863,9 +6863,23 @@ gfc_conv_intrinsic_ishftc (gfc_se * se, gfc_expr * expr)

   if (num_args == 3)
     {
+      gfc_expr *size = expr->value.function.actual->next->next->expr;
+
       /* Use a library function for the 3 parameter version.  */
       tree int4type = gfc_get_int_type (4);

+      /* Treat optional SIZE argument when it is passed as an optional
+	 dummy.  If SIZE is absent, the default value is BIT_SIZE(I).  */
+      if (size->expr_type == EXPR_VARIABLE
+	  && size->symtree->n.sym->attr.dummy
+	  && size->symtree->n.sym->attr.optional)
+	{
+	  tree type_of_size = TREE_TYPE (args[2]);
+	  args[2] = build3_loc (input_location, COND_EXPR, type_of_size,
+				gfc_conv_expr_present (size->symtree->n.sym),
+				args[2], fold_convert (type_of_size, nbits));
+	}
+
       /* We convert the first argument to at least 4 bytes, and
 	 convert back afterwards.  This removes the need for library
 	 functions for all argument sizes, and function will be
diff --git a/gcc/testsuite/gfortran.dg/ishftc_optional_size_1.f90 b/gcc/testsuite/gfortran.dg/ishftc_optional_size_1.f90
new file mode 100644
index 00000000000..1ccf4b38caa
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/ishftc_optional_size_1.f90
@@ -0,0 +1,97 @@
+! { dg-do run }
+!
+! PR fortran/67277 - ISHFTC and missing optional argument SIZE
+
+module m
+  implicit none
+contains
+  ! Optional argument passed by reference
+  elemental function ishftc4_ref (i, shift, size_) result(r)
+    integer(4), intent(in)           :: i
+    integer,    intent(in)           :: shift
+    integer,    intent(in), optional :: size_
+    integer                          :: r
+    r = ishftc (i, shift=shift, size=size_)
+  end
+
+  elemental function ishftc1_ref (i, shift, size_) result(r)
+    integer(1), intent(in)           :: i
+    integer,    intent(in)           :: shift
+    integer(1), intent(in), optional :: size_
+    integer(1)                       :: r
+    r = ishftc (i, shift=shift, size=size_)
+  end
+
+  ! Array valued argument i
+  function ishftc4_ref_4 (i, shift, size_) result(r)
+    integer(4), intent(in)           :: i(4)
+    integer,    intent(in)           :: shift
+    integer,    intent(in), optional :: size_
+    integer                          :: r(size(i))
+    r = ishftc (i, shift=shift, size=size_)
+  end
+
+  ! Optional argument passed by value
+  elemental function ishftc4_val (i, shift, size_) result(r)
+    integer(4), intent(in)           :: i
+    integer,    intent(in)           :: shift
+    integer,    value,      optional :: size_
+    integer                          :: r
+    r = ishftc (i, shift=shift, size=size_)
+  end
+
+  elemental function ishftc1_val (i, shift, size_) result(r)
+    integer(1), intent(in)           :: i
+    integer,    intent(in)           :: shift
+    integer(1), value,      optional :: size_
+    integer(1)                       :: r
+    r = ishftc (i, shift=shift, size=size_)
+  end
+
+  ! Array valued argument i
+  function ishftc4_val_4 (i, shift, size_) result(r)
+    integer(4), intent(in)           :: i(4)
+    integer,    intent(in)           :: shift
+    integer,    value,      optional :: size_
+    integer                          :: r(size(i))
+    r = ishftc (i, shift=shift, size=size_)
+  end
+end module m
+
+program p
+  use m
+  implicit none
+  integer    :: shift = 1
+  integer(4) :: i4 = 127, j4(4), k4(4)
+  integer(1) :: i1 = 127
+  integer(4) :: expect4
+  integer(1) :: expect1
+
+  ! Scalar variants
+  expect4 = 2*i4
+  if (ishftc      (i4, shift) /= expect4) stop 1
+  if (ishftc4_ref (i4, shift) /= expect4) stop 2
+  if (ishftc4_val (i4, shift) /= expect4) stop 3
+
+  expect1 = -2_1
+  if (ishftc      (i1, shift) /= expect1) stop 4
+  if (ishftc1_ref (i1, shift) /= expect1) stop 5
+  if (ishftc1_val (i1, shift) /= expect1) stop 6
+
+  ! Array arguments
+  expect4 = 2*i4
+  j4 = i4
+  k4 = ishftc        (j4, shift)
+  if (any (k4 /= expect4)) stop 7
+
+  ! The following works on x86_64 but might currently fail on other systems:
+  ! (see PR113377)
+! k4 = ishftc4_val_4 (j4, shift)
+! if (any (k4 /= expect4)) stop 8
+
+  ! The following currently segfaults (might be a scalarizer issue):
+  ! (see PR113377)
+! k4 = ishftc4_ref_4 (j4, shift)
+! print *, k4
+! if (any (k4 /= expect4)) stop 9
+end program p
--
2.35.3