Re: [PATCH] cgraph: Handle simd clones in cgraph_node::set_{const,pure}_flag [PR106433]

[Jan Hubicka <hubicka@ucw.cz>]

> On Wed, Feb 08, 2023 at 06:10:08PM +0100, Jan Hubicka wrote:
> > My understanding of simd clones is bit limited, but I think you are
> > right that they should have the same semantics as their caller.
> > 
> > I think const may be one that makes compiler to ICE, but
> > there are many other places where function body is analyzed and all its
> > aliases/thunks and other variants should be updated too.  For exmaple
> > set_pure_flag, nothrow, noreturn and analysis done by modref,
> > ipa-refernece etc.
> > 
> > I wonder if we want to update them all and hide that in some
> > abstraction?  Next stage 1 I can work on inventing iterators for those
> > kind of things as current approach combinindg direct walkters and
> > function wrappers has become bit hard to maintain in cases like this.
> 
> I think it depends on whether we do that analysis or update it post IPA
> or not.  Because simd clones are created very late during IPA, if say
> the nothrow, noreturn, modref etc. analysis is done only during IPA or
> before it, we don't need to walk the simd clones.
> It is just for late GIMPLE analysis that changes flags that later on
> could be used in callers of those functions.
> pure/const flag is what I know can happen this late, what else?

We have late pure/const (doing pure, const, nothrow, noreturn), modref
(which also discovers pure/const attributes and produces its own
summaries) and except.c at the very end of copimlation can set notrow
flag...

This is all I can think of. 
Honza
> 
> 	Jakub
>