------- Comment #1 from jakub at gcc dot gnu dot org 2008-04-22 19:53 -------
4.2 would recreate the call:
/* Wrap the computation of the argument in a SAVE_EXPR, as we may
need to expand the argument again. This way, we will not perform
side-effects more the once. */
narg = builtin_save_expr (arg);
if (narg != arg)
{
arg = narg;
arglist = build_tree_list (NULL_TREE, arg);
exp = build_function_call_expr (fndecl, arglist);
}
and thus the CALL_EXPR_TAILCALL bit would be lost. Now if target = expand_unop
(mode, builtin_optab, op0, target, 0); fails, then it is certainly better to
preserve the CALL_EXPR_TAILCALL bit. But for the errno check we need to either
clear it, or branch to (return).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36017
