On Wed, Jan 18, 2023 at 01:39:18PM +0100, Andreas Schwab wrote:
> On Jan 18 2023, Jakub Jelinek wrote:
>
> > With LTO each function has the DECL_FUNCTION_SPECIFIC_OPTIMIZATION
> > (and _TARGET), for functions with optimize attribute obviously as without
> > LTO specific to what options have been overridden (but with defaults from
> > TU's command line etc.), for functions without that simply with what
> > options has the TU.
>
> Sorry, I cannot parse that sentence. Could you please try again?
After parsing options GCC creates an OPTIMIZATION_NODE tree with all the
PerFunction/Optimization option state recorded in it (and more).
That node is then when writing LTO attached to each function (different
node if a function has optimize attribute etc.).
That is streamed in by lto1 back and on each set_cfun such saved options
are stored into global_options{,_set}.
> > lto1 then streams in those options and when switching functions switches
> > the global options.
>
> Why does that not work then?
I don't know what doesn't work. You haven't mentioned what kind of PR
you're trying to fix or what problem you are seeing.
Jakub
