On 5/24/22 16:21, Marek Polacek wrote:
On Tue, May 24, 2022 at 04:01:37PM -0400, Jason Merrill wrote:
On 5/24/22 09:55, Marek Polacek wrote:
On Tue, May 24, 2022 at 08:36:39AM -0400, Jason Merrill wrote:
On 5/16/22 11:36, Marek Polacek wrote:
+static tree
+replace_placeholders_for_class_temp_r (tree *tp, int *, void *data)
+{
+ tree t = *tp;
+ tree full_expr = *static_cast<tree *>(data);
+
+ /* We're looking for a TARGET_EXPR nested in the whole expression. */
+ if (TREE_CODE (t) == TARGET_EXPR
+ && !potential_prvalue_result_of (t, full_expr))
+ {
+ tree init = TARGET_EXPR_INITIAL (t);
+ while (TREE_CODE (init) == COMPOUND_EXPR)
+ init = TREE_OPERAND (init, 1);
Hmm, how do we get a COMPOUND_EXPR around a CONSTRUCTOR?
Sadly, that's possible for code like (from nsdmi-aggr18.C)
struct D {
int x = 42;
B b = (true, A{x});
};
where the TARGET_EXPR_INITIAL is
<<< Unknown tree: void_cst >>>, {.x=((struct D *) this)->x, .y=(&<PLACEHOLDER_EXPR
struct A>)->x}
Hmm, perhaps cp_build_compound_expr should build an additional TARGET_EXPR
around the COMPOUND_EXPR but leave the one inside alone. Feel free to
investigate that if you'd like, or the patch is OK as is.
Sorry, I was unclear. The whole expression is:
TARGET_EXPR <D.2439, A::operator B (&TARGET_EXPR <D.2405, <<< Unknown tree: void_cst >>>,
{.x=((struct D *) this)->x, .y=(&<PLACEHOLDER_EXPR struct A>)->x}>)>
so there *is* a TARGET_EXPR around the COMPOUND_EXPR.
Yes, but that's because cp_build_compound_expr changes
TARGET_EXPR_INITIAL of the TARGET_EXPR from the CONSTRUCTOR to the
COMPOUND_EXPR; I'm suggesting it might build a new one instead.
We'd have to build
a TARGET_EXPR around the COMPOUND_EXPR's RHS = the CONSTRUCTOR. Frankly,
I'm not sure if it's worth the effort. The while loop is somewhat unsightly
but not too bad.
Agreed.
Jason
