Re: df.c and partial writes/REG_EQUAL notes

[Jan Hubicka <jh@suse.cz>]

> Don't bother, i already did it.
> You'll note that reload makes too many bitmaps, and the 16-24 bytes
> more overhead + the empty array pointers that the ebitmap takes causes
> 100-150 meg more memory.
> Just another point that we shouldn't up and replace them wholesale,
> rather do it incrementally.
> 
> I have resolved this problem by reworking the internals to
> not need to store empty words at all (ie not even pointers to them).

How did you accomplished that?
Is that contained in the updated ebitmap patch?
> 
> I also replaced bitmaps with them already.  The new internal storage
> mechanism requires changes to sbitmaps so you can properly
> and/or/copy/etc bitmaps of differing bit sizes.
> I.E. it'll do the right thing, as long as the destination is big
> enough to hold the right result. sbitmap_a_or_b (350 bit sbitmap, 25
> bit sbitmap, 200 bit sbitmap) will work properly.
> It would and/or/etc random memory before.
> 
> However, experience in doing this just helps prove my point. I tried
> doing it all at once, and it made finding the real cause of the bugs
> impossible.

Thats understandable - it happends in gcc commonly :(
> 
> > > 
> >> This was your "review".
> > Please lets work together to get gcc better, not fight.
> Who is fighting?
> I put review in quotes because i do not believe he reviewed the patch
> itself, as i stated in my message to Gerald.
> 
> I should also note that there was a bug in ebitmap.h in
> EXECUTE_IF_SET_IN_EBITMAP that a meaningful review of the patch would
> have caught. 
> 
> >
> > Honza
> > > 
> >> >
> >> > r~
> >> 
> >> -- 
> >> "When I was five years old I was on a merry go round.  There was
> >> a gunshot nearby.  The horses stampeded.  There I was running
> >> down the street on a purple wooden horse.
> >> "-Steven Wright
> 
> -- 
> "Last time I went skiing, I had to get up at 5:00 in the morning.
> I knew I couldn't do that, so I slept with my skis on.  My ride
> came at 5:30 in the morning, couldn't wake me up so he carried
> me out of the house, put my skis on the roof rack of the car,
> and drove to the mountain.  Seventeen miles later, I woke up out
> of this incredibly bizarre dream that I was skydiving
> horizontally.  I'm sure this has happened to you.
> "-Steven Wright