https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70937
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
For gfortran.dg/array_constructor_type_7.f03 the difference is
@@ -13,6 +13,7 @@
bitsizetype D.3466;
sizetype D.3467;
+ typedef character(kind=1) struct
character(kind=1)[1:2][1:.arr][1:2][1:.arr];
D.3462 = (bitsizetype) (sizetype) _s * 8;
D.3463 = (sizetype) _s;
D.3464 = (bitsizetype) (sizetype) _a1 * 8;
which results in
try
{
D.3477 = D.3458;
D.3478 = D.3477 * 2;
D.3479 = D.3459;
...
.arr = MAX_EXPR <_9, 0>;
_10 = (sizetype) .arr;
_11 = (bitsizetype) _10;
D.3458 = _11 * 8;
and thus an uninitialized use of D.3458.
Note there _is_ already a decl expr, but it looks like
stmt <decl_expr 0x7ffff6a4eb60 type <array_type 0x7ffff6a4b498>
side-effects arg 0 <var_decl 0x7ffff7ff6a20 arr>
so it is for a VAR_DECL. It looks like the Fortran FE "gimplifes" type
sizes on its own (in some cases at least). The above is built here:
void
gfc_trans_auto_array_allocation (tree decl, gfc_symbol * sym,
gfc_wrapped_block * block)
{
...
/* Evaluate character string length. */
if (sym->ts.type == BT_CHARACTER
&& onstack && !INTEGER_CST_P (sym->ts.u.cl->backend_decl))
{
gfc_conv_string_length (sym->ts.u.cl, NULL, &init);
gfc_trans_vla_type_sizes (sym, &init);
/* Emit a DECL_EXPR for this variable, which will cause the
gimplifier to allocate storage, and all that good stuff. */
tmp = fold_build1_loc (input_location, DECL_EXPR, TREE_TYPE (decl),
decl);
gfc_add_expr_to_block (&init, tmp);
and gfc_trans_vla_type_sizes has the interesting comment:
/* Make sure all type sizes and array domains are either constant,
or variable or parameter decls. This is a simplified variant
of gimplify_type_sizes, but we can't use it here, as none of the
variables in the expressions have been gimplified yet.
As type sizes and domains for various variable length arrays
contain VAR_DECLs that are only initialized at gfc_trans_deferred_vars
time, without this routine gimplify_type_sizes in the middle-end
could result in the type sizes being gimplified earlier than where
those variables are initialized. */
void
gfc_trans_vla_type_sizes (gfc_symbol *sym, stmtblock_t *body)
This code was added by Jakub ten years ago.
I can fix the wrong-code regressions by restricting place_decl_expr to work
on pointer types. But all this looks like the wrong way to fix the FE
issue of missing DECL_EXPRs for some of its "anonymous" types it generates.
But the above FE "gimplification" code suggests that it is wrong if the
gimplifier ever sees non-gimplified type sizes.
In this case the FE generated
{
integer(kind=8) D.3445;
D.3445 = args->dim[0].stride;
stride.1 = D.3445 != 0 ? D.3445 : 1;
args.0 = (character(kind=1)[0:D.3448][1:_args] * restrict) args->data;
ubound.0 = (args->dim[0].ubound - args->dim[0].lbound) + 1;
size.3 = stride.1 * ubound.0;
offset.2 = -stride.1;
D.3446 = (bitsizetype) (sizetype) _args * 8;
which is gimplified to
_4 = (sizetype) _args;
_5 = (bitsizetype) _4;
D.3446 = _5 * 8;
but the expression (sizetype) _args was also used in the TYPE_DECLs
array type TYPE_SIZE
SAVE_EXPR <((bitsizetype) _4 * (bitsizetype) (sizetype) ubound.0) * 8>
which the FE "gimplification" doesn't adjust.
The type we end up "gimplifying" is the one built by gfc_build_qualified_array.
They are connected via TYPE_NAME (but they do not share sizes, they even
use differently named decls):
SAVE_EXPR <((bitsizetype) (sizetype) _args * (bitsizetype) (sizetype) ubound.0)
* 8>
SAVE_EXPR <((bitsizetype) (sizetype) _args * (bitsizetype) (sizetype) size.3) *
8>
So the following patch also fixes this PR.
Index: gcc/fortran/trans-decl.c
===================================================================
--- gcc/fortran/trans-decl.c (revision 235945)
+++ gcc/fortran/trans-decl.c (working copy)
@@ -3818,6 +3818,9 @@ gfc_trans_vla_type_sizes (gfc_symbol *sy
}
gfc_trans_vla_type_sizes_1 (type, body);
+ if (TYPE_NAME (type)
+ && TREE_TYPE (TYPE_NAME (type)) != type)
+ gfc_trans_vla_type_sizes_1 (TREE_TYPE (TYPE_NAME (type)), body);
}
or the following, only making sure to get the unsharing correct.
Index: gcc/fortran/trans-decl.c
===================================================================
--- gcc/fortran/trans-decl.c (revision 235945)
+++ gcc/fortran/trans-decl.c (working copy)
@@ -3818,6 +3818,11 @@ gfc_trans_vla_type_sizes (gfc_symbol *sy
}
gfc_trans_vla_type_sizes_1 (type, body);
+ /* gfc_build_qualified_array may have built this type but left TYPE_NAME
+ pointing to the original type whose type sizes we need to expose to
+ the gimplifier unsharing. */
+ if (TYPE_NAME (type))
+ gfc_add_expr_to_block (body, build1 (DECL_EXPR, type, TYPE_NAME (type)));
}
the last one I am testing now.
