[gcc/devel/coarray_native] Set DECL_ARTIFICIAL on gfortran internal variables.

["Thomas König" <tkoenig@gcc.gnu.org>]

https://gcc.gnu.org/g:a039ddac6d248f06184f1eece05d1da513917d69

commit a039ddac6d248f06184f1eece05d1da513917d69
Author: Thomas Koenig <tkoenig@gcc.gnu.org>
Date:   Sun Dec 20 16:27:01 2020 +0100

    Set DECL_ARTIFICIAL on gfortran internal variables.
    
    It seems we sometimes use DECL_ARTIFICIAL as choosing between
    different code paths.  In order not to make -fdebug-aux-vars
    do different things, set DECL_ARTIFICIAL on the variables to
    avoid these different code paths (and the corresponding
    regressions).
    
    gcc/fortran/ChangeLog:
    
            * trans.c (create_var_debug_raw): Set DECL_ARTIFICIAL
            on variables.
    
    (cherry picked from commit 8d76c007afe4c70f51fd56b0e5b89522de5de61f)

Diff:
---
 gcc/fortran/trans.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gcc/fortran/trans.c b/gcc/fortran/trans.c
index fa7fd9d88aa..57a344a63c9 100644
--- a/gcc/fortran/trans.c
+++ b/gcc/fortran/trans.c
@@ -128,6 +128,9 @@ create_var_debug_raw (tree type, const char *prefix)
 
   t = build_decl (input_location, VAR_DECL, get_identifier (name_buf), type);
 
+  /* Not setting this causes some regressions.  */
+  DECL_ARTIFICIAL (t) = 1;
+
   /* We want debug info for it.  */
   DECL_IGNORED_P (t) = 0;
   /* It should not be nameless.  */