[Bug fortran/88364] [9 Regression] Wrong-code due to CLOBBER

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88364

--- Comment #4 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
A simple fix is not to do the clobbers if there is a reference:

Index: trans-expr.c
===================================================================
--- trans-expr.c        (Revision 266250)
+++ trans-expr.c        (Arbeitskopie)
@@ -8152,7 +8152,7 @@ gfc_conv_expr_reference (gfc_se * se, gfc_expr * e
          gfc_add_block_to_block (&se->pre, &se->post);
          se->expr = var;
        }
-      else if (add_clobber)
+      else if (add_clobber && expr->ref == NULL)
        {
          tree clobber;
          tree var;


A bit more sophisticated would be to actually build the correct
clobber in this case.

I'm inclined to commit the patch above and open a new PR for
the missed optimization, but I won't have time for either in
the next few days.

So, if anybody wants to do anything about this, be my guest :-)