On Mon, 22 May 2023, Richard Biener wrote:

> On Thu, May 18, 2023 at 11:04 PM Alexander Monakov via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > Implement -ffp-contract=on for C and C++ without changing default
> > behavior (=off for -std=cNN, =fast for C++ and -std=gnuNN).
> 
> The documentation changes mention the defaults are changed for
> standard modes, I suppose you want to remove that hunk.

No, the current documentation is incomplete, and that hunk extends it
to match the current GCC behavior. Should I break it out to a separate
patch? I see this drive-by fix could look confusing — sorry about that.

> it would be possible to do
> 
>   *expr_p = build_call_expr_internal (ifn, type, ops[0], ops[1]. ops[2]);
>   return GS_OK;
> 
> and not worry about temporary creation and gimplifying of the operands.
> That would in theory also leave the possibility to do this during
> genericization instead (and avoid the guard against late invocation of
> the hook).

Ah, no, I deliberately decided against that, because that way we would go
via gimplify_arg, which would emit all side effects in *pre_p. That seems
wrong if arguments had side-effects that should go in *post_p.

Thanks.
Alexander

> Otherwise it looks OK, but I'll let frontend maintainers have a chance to look
> as well.
> 
> Thanks for tackling this long-standing issue.
> Richard.