On Tue, Jan 31, 2017 at 12:15:36PM +0100, Martin Jambor wrote:
> > I've committed it as is, feel free to propose changes. But before that, we
> > should figure out what to do with -fipa-cp-alignment. Should it have
> > Ignore flag and
> > Does nothing. Preserved for backward compatibility.
> > description in common.opt, and
> >
> > @item -fipa-cp-alignment
> > @opindex -fipa-cp-alignment
> > When enabled, this optimization propagates alignment of function
> > parameters to support better vectorization and string operations.
> >
> > This flag is enabled by default at @option{-O2} and @option{-Os}. It
> > requires that @option{-fipa-cp} is enabled.
> > @option{-fipa-cp-alignment} is obsolete, use @option{-fipa-bit-cp} instead.
> >
> > removed altogether, or should it say be alias for -fipa-bit-cp?
>
> Well, -fipa-bit-cp is a superset of the old -fipa-cp-alignment in the
> sense that the latter worked only for pointers whereas the former now
> also operates on integers.
>
> We could still refuse to store results of the analysis to pointers if
> user provided -fno-ipa-cp-alignment, but I do not think it is
> reasonable. My preference would be to mark it obsolete and document
> that -fipa-bit-cp should be used instead.
What are obsolete options? Do you mean deprecated or removed?
We have ignored options retained just for compatibility that do nothing.
-fipa-cp-alignment does nothing right now (nothing ever checks it), but
it isn't declared as Ignore and is documented (ignored options aren't
documented). The current state is that e.g. x_flag_ipa_cp_alignment is
still a field in global_options* etc.
Jakub
