Re: PATCH: PR middle-end/33007: builtin lround doesn't work

["Richard Guenther" <richard dot guenther at gmail dot com>]

On 8/7/07, H.J. Lu <hjl@lucon.org> wrote:
> fold_fixed_mathfn may turn builtin lround into FIX_TRUNC_EXPR. But
> expand_builtin_int_roundingfn_2 isn't prepared to deal with it. This
> patch checks return from expand_expr and handle FIX_TRUNC_EXPR.
>

This is not the right way to fix this really.  Instead this is the
common problem
that build_call_expr folds the built expression.  Instead for

  /* 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;
      exp = build_call_expr (fndecl, 1, arg);
    }

we should re-build the call expression _without_ folding it.  (Or
rather we can fix
the place that created the call without folding it - that is, fold
during TER).  See
for example expand_builtin_cexpi or others which make sure not to re-fold the
call expression.

Richard.