------- Comment #16 from hubicka at ucw dot cz 2007-06-22 23:59 -------
Subject: Re: [4.3 Regression] cannot take address of bit field
>
> Yes. It looks like a frontend bug if the tree was not marked addressable
> before gimplification but would need to after.
This does not seem to be so easy, sadly. The occurences of missing
addressables are in a cases gimplifier expanding stuff into address
expression (so the address is not strictly taken in the language sense)
The attached patch bootstraps/regtests. I am simply using the gimple
code a-la ssa-alias.c to set the addressable flag instead of hooking
into frontend.
In some sense I like it because I don't think frontends needs to be in
busyness in computing TREE_ADDRESSABLE bit for middle end. On the other
hand I guess I should spend some time tomorrow to produce simple C++
testcases where the FE fails to set the bit.
Index: gimplify.c
===================================================================
--- gimplify.c (revision 125921)
+++ gimplify.c (working copy)
@@ -117,6 +117,17 @@ static enum gimplify_status gimplify_com
static bool cpt_same_type (tree a, tree b);
#endif
+/* Mark X addressable. Unlike the langhook we expect X to be in gimple
+ form and we don't do any syntax checking. */
+static void
+mark_addressable (tree x)
+{
+ while (handled_component_p (x))
+ x = TREE_OPERAND (x, 0);
+ if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
+ return ;
+ TREE_ADDRESSABLE (x) = 1;
+}
/* Return a hash value for a formal temporary table entry. */
@@ -3434,7 +3445,7 @@ gimplify_modify_expr_rhs (tree *expr_p,
if (use_target)
{
CALL_EXPR_RETURN_SLOT_OPT (*from_p) = 1;
- lang_hooks.mark_addressable (*to_p);
+ mark_addressable (*to_p);
}
}
@@ -3957,6 +3968,8 @@ gimplify_addr_expr (tree *expr_p, tree *
the address of a call that returns a struct; see
gcc.dg/c99-array-lval-1.c. The gimplifier will correctly make
the implied temporary explicit. */
+
+ /* Mark the RHS addressable. */
ret = gimplify_expr (&TREE_OPERAND (expr, 0), pre_p, post_p,
is_gimple_addressable, fb_either);
if (ret != GS_ERROR)
@@ -3972,8 +3985,7 @@ gimplify_addr_expr (tree *expr_p, tree *
is set properly. */
recompute_tree_invariant_for_addr_expr (expr);
- /* Mark the RHS addressable. */
- lang_hooks.mark_addressable (TREE_OPERAND (expr, 0));
+ mark_addressable (TREE_OPERAND (expr, 0));
}
break;
}
@@ -4011,7 +4023,7 @@ gimplify_asm_expr (tree *expr_p, tree *p
&allows_mem, &allows_reg, &is_inout);
if (!allows_reg && allows_mem)
- lang_hooks.mark_addressable (TREE_VALUE (link));
+ mark_addressable (TREE_VALUE (link));
tret = gimplify_expr (&TREE_VALUE (link), pre_p, post_p,
is_inout ? is_gimple_min_lval : is_gimple_lvalue,
@@ -4140,7 +4152,7 @@ gimplify_asm_expr (tree *expr_p, tree *p
{
tret = gimplify_expr (&TREE_VALUE (link), pre_p, post_p,
is_gimple_lvalue, fb_lvalue | fb_mayfail);
- lang_hooks.mark_addressable (TREE_VALUE (link));
+ mark_addressable (TREE_VALUE (link));
if (tret == GS_ERROR)
{
error ("memory input %d is not directly addressable", i);
@@ -5562,7 +5574,7 @@ gimplify_expr (tree *expr_p, tree *pre_p
if (fallback == fb_lvalue)
{
*expr_p = get_initialized_tmp_var (*expr_p, pre_p, post_p);
- lang_hooks.mark_addressable (*expr_p);
+ mark_addressable (*expr_p);
}
break;
@@ -5575,7 +5587,7 @@ gimplify_expr (tree *expr_p, tree *pre_p
if (fallback == fb_lvalue)
{
*expr_p = get_initialized_tmp_var (*expr_p, pre_p, post_p);
- lang_hooks.mark_addressable (*expr_p);
+ mark_addressable (*expr_p);
}
break;
@@ -5763,7 +5775,7 @@ gimplify_expr (tree *expr_p, tree *pre_p
else if (fallback == fb_lvalue)
{
*expr_p = get_initialized_tmp_var (*expr_p, pre_p, post_p);
- lang_hooks.mark_addressable (*expr_p);
+ mark_addressable (*expr_p);
}
else
ret = GS_ALL_DONE;
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31541
