[Bug fortran/93148] Pointer-function-result as LVALUE variable – function called multiple times with copy-in/out

[Bug fortran/93148] Pointer-function-result as LVALUE variable – function called multiple times with copy-in/out

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93148

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Also when looking at gfc_conv_subref_array_arg – the function is called
seemingly up to 3 times – once per:

* gfc_conv_loop_setup (&loop, &expr->where);
   which calls gfc_conv_loop_setup → gfc_conv_loop_setup →
gfc_conv_procedure_call
   → gfc_trans_create_temp_array

* gfc_conv_expr (&lse, expr);

* gfc_conv_is_contiguous_expr (&cont_se, expr);
  (which calls: "gfc_conv_expr_descriptor (&array_se, expr);")

[Bug fortran/93148] Pointer-function-result as LVALUE variable – function called multiple times with copy-in/out

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93148

--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Additionally, it seems as if the contiguous check used for
gfortran.dg/contiguous_10.f90 currently unconditionally copies in the data –
which causes a problem when the pointer address escapes.

(Okay, whether that works is implementation defined per F2018:15.5.2.4
paragraph 9, but it is still a missed optimizion.)  – Lightly related to the
issue above as the issue shows up with copy-in/copy-out. Possible fix - which
causes a multi-call issue for gfortran.dg/contiguous_10.f90, see previous
comment:

--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -6528,5 +6528,7 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
                  gfc_conv_subref_array_arg (&parmse, e, nodesc_arg,
                                             fsym->attr.intent,
-                                            fsym->attr.pointer);
+                                            fsym->attr.pointer, fsym,
+                                            sym->name, NULL,
+                                            /* check_contiguous= */ true);
                }
              else