re PR fortran/71544 (gfortran compiler optimization bug when dealing with c-style pointers)

2019-03-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/71544
	* trans-types.c (gfc_typenode_for_spec) Set ts->is_c_interop of
	C_PTR and C_FUNPTR.
	(create_fn_spec): Mark argument as escaping if ts->is_c_interop is set.

2019-03-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/71544
	* gfortran.dg/c_ptr_tests_19.f90: New test.

From-SVN: r269532

gcc/fortran/ChangeLog

+2019-03-09  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/71544
+	* trans-types.c (gfc_typenode_for_spec) Set ts->is_c_interop of
+	C_PTR and C_FUNPTR.
+	(create_fn_spec): Mark argument as escaping if ts->is_c_interop is set.
+
 2019-03-09  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/84504

gcc/fortran/trans-types.c

@@ -1177,6 +1177,7 @@ gfc_typenode_for_spec (gfc_typespec * spec, int codim)
           spec->type = BT_INTEGER;
           spec->kind = gfc_index_integer_kind;
 	  spec->f90_type = BT_VOID;
+	  spec->is_c_interop = 1;  /* Mark as escaping later.  */
         }
       break;
     case BT_VOID:
@@ -2957,7 +2958,8 @@ create_fn_spec (gfc_symbol *sym, tree fntype)
 		    || f->sym->ts.u.derived->attr.pointer_comp))
 	    || (f->sym->ts.type == BT_CLASS
 		&& (CLASS_DATA (f->sym)->ts.u.derived->attr.proc_pointer_comp
-		    || CLASS_DATA (f->sym)->ts.u.derived->attr.pointer_comp)))
+		    || CLASS_DATA (f->sym)->ts.u.derived->attr.pointer_comp))
+	    || (f->sym->ts.type == BT_INTEGER && f->sym->ts.is_c_interop))
 	  spec[spec_len++] = '.';
 	else if (f->sym->attr.intent == INTENT_IN)
 	  spec[spec_len++] = 'r';

gcc/testsuite/ChangeLog

+2019-03-09  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/71544
+	* gfortran.dg/c_ptr_tests_19.f90: New test.
+
 2019-03-09  John David Anglin  <dave.anglin@bell.net>
 
 	* gnat.dg/debug11.adb: Skip on 32-bit hppa*-*-hpux*.

gcc/testsuite/gfortran.dg/c_ptr_tests_19.f90

+! { dg-do run }
+
+! PR 71544 - this failed with some optimization options due to a
+! pointer not being marked as escaping.
+
+module store_cptr
+    use, intrinsic :: iso_c_binding
+    implicit none
+    public
+    type(c_ptr), save :: cptr
+end module store_cptr
+
+subroutine init()
+    use, intrinsic :: iso_c_binding
+    implicit none
+    integer(c_int), pointer :: a
+    allocate(a)
+    call save_cptr(c_loc(a))
+    a = 100
+end subroutine init
+
+subroutine save_cptr(cptr_in)
+    use store_cptr
+    implicit none
+    type(c_ptr), intent(in) :: cptr_in
+    cptr = cptr_in
+end subroutine save_cptr
+
+program init_fails
+    use store_cptr
+    implicit none
+    integer(c_int), pointer :: val
+    call init()
+    call c_f_pointer(cptr,val)
+    if (val /= 100) stop 1
+end program init_fails