<stefan@xxxxxxxxx> writes:
> I'm working on a new optimization to get rid of spilled tmp variables (e.g.
> introduced by pre) to use the source mem ref instead of a stack slot.
>
> To do this, I added a loop into ira.c:ira()
>
> init_prune_stack_vars ();
> do
> {
> #ifndef IRA_NO_OBSTACK
> gcc_obstack_init (&ira_obstack);
> #endif
> bitmap_obstack_initialize (&ira_bitmap_obstack);
>
> ...
>
> ira_color ();
>
> }
> while (flag_prune_stack_vars && prune_stack_vars ());
>
> To get it work, the prune_stack_vars function resets a couple of data.
> This is mostly working - but on some source files, it fails due to invalid
> reg_equivs.
> Since this also happens, if the optimizer does nothing and just loops once.
>
> Currently I'm calling this, before looping again
>
> regstat_free_n_sets_and_refs ();
> regstat_free_ri ();
> loop_optimizer_finalize ();
> free_dominance_info (CDI_DOMINATORS);
>
> Any hint, what I'm missing to reset?
I can't see anything obviously missing. What kind of failure do
you see? E.g. do you get an internal compiler error or does the
compiler generate incorrect code?
Do you see the failure on an in-tree test case? FWIW, I just tried
looping like this locally and didn't see any failures for the tests
I tried. But I was obviously testing without the new optimisation,
and so each loop iteration should just repeat what the previous one did.
Not related to the failure, but: do you do anything with the obstacks
when looping again? Including the initialisations in the loop as above
would introduce a memory leak if you don't do anything to free the contents.
It'd probably be better to initialise outside the loop unless you're
really confident that the no data is carried across iterations.
Thanks,
Richard
