https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105256
--- Comment #19 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The TARGET_EXPR is elided in gimplify_modify_expr_rhs:
case TARGET_EXPR:
{
/* If we are initializing something from a TARGET_EXPR, strip the
TARGET_EXPR and initialize it directly, if possible. This can't
be done if the initializer is void, since that implies that the
temporary is set in some non-trivial way.
??? What about code that pulls out the temp and uses it
elsewhere? I think that such code never uses the TARGET_EXPR as
an initializer. If I'm wrong, we'll die because the temp won't
have any RTL. In that case, I guess we'll need to replace
references somehow. */
tree init = TARGET_EXPR_INITIAL (*from_p);
if (init
&& (TREE_CODE (*expr_p) != MODIFY_EXPR
|| !TARGET_EXPR_NO_ELIDE (*from_p))
&& !VOID_TYPE_P (TREE_TYPE (init)))
{
*from_p = init;
ret = GS_OK;
changed = true;
}
}
break;
Though, can the TARGET_EXPR be elided if there are PLACEHOLDER_EXPRs in it?
If not, something should probably set TARGET_EXPR_NO_ELIDE somewhere.
If yes, perhaps we need to replace_placeholders perhaps through a language hook
at the
above point. But it is unclear to what it should be replaced...
