On Thu, Nov 26, 2015 at 05:05:09PM +0000, Joseph Myers wrote:
> On Thu, 26 Nov 2015, Jakub Jelinek wrote:
>
> > > Also, on further consideration: the folding via c_fully_fold is relied
> > > upon to get information about whether an expression contains anything
> > > that
> > > cannot occur in an evaluated part of a constant expression / outside
> > > sizeof in a constant expression in C90 mode. So if a SAVE_EXPR is
> > > created
> > > by language-independent code, c_fully_fold doesn't see inside it and you
> > > lose that information. What that says to me is that maybe a better
> > > interim solution would be a lang hook for the folders to use to call
> > > c_save_expr instead of save_expr. And then longer term: (a) maybe any
> > > folding that involves duplicating expressions and so needs to create
> >
> > But the condition whether to call c_save_expr or whether to call save_expr
> > instead is not constant in the C FE.
> > If c_fully_fold is expected to be called on the expression, then c_save_expr
> > needs to be used, otherwise save_expr.
> > Can we rely on in_late_binary_op for that?
>
> Yes, I think so.
It seems only to be set temporarily when calling convert*, then reset
back, while we supposedly want to use save_expr instead of c_save_expr also
at the point where we are genericizing, or gimplifying etc.
Jakub
