Re: mainline "exploding"

[Mark Mitchell <mark at codesourcery dot com>]

On Wed, 2003-10-15 at 03:40, Jan Hubicka wrote:
> > On Tue, 14 Oct 2003, Jan Hubicka wrote:
> > > 
> > > > 2) go ahead and enable unit-at-a-time by default for C++ at all levels
> >  
> > On Tue, Oct 14, 2003 at 02:28:53PM +0200, Michael Matz wrote:
> > > IMHO, if possible we should go this way.  Maybe combined with lower limits
> > > at -O1.  In the long run I see no sense in having two inlining heuristics.
> > 
> > Certainly if we have two inlining algorithms we have to keep maintaining,
> > tuning, and bug-fixing two inlining algorithms.  Making the poorer one go
> > away seems advisable.  I might have been confused, but the main argument
> > I heard against using unit-at-a-time all the time was memory, so if we
> > actually need more memory to use the old algorithm in many cases, that kills
> > that.
> 
> Memory footprint does not appear to be catastrophical.  Even with
> inlining disabled, for many copilation units, such as  combine.c the
> peak is actually lower with -funit-at-a-time than without.

I think that every one agrees that -funit-at-a-time is where we want to
go.  That was my plan when I implementation function-at-a-time years
ago; it's clearly the right thing from a design perspective, and it is
what every other compiler does.  Therefore, if it uses more memory than
other compilers it's because of problems with GCC, not problems with the
idea of -funit-at-a-time.

I think we should make -funit-at-a-time the default at this point, if it
is passing test suites.

In fact, I think we should make it *unconditional*.  There is no need
for this to be an option; it should be the only mode.

-- 
Mark Mitchell <mark@codesourcery.com>
CodeSourcery, LLC