This is the mail archive of the
mailing list for the GCC project.
Re: better -Wuninitialized (Re: Ada files now checked in)
- To: Zack Weinberg <zack at codesourcery dot com>
- Subject: Re: better -Wuninitialized (Re: Ada files now checked in)
- From: Daniel Berlin <dan at cgsoftware dot com>
- Date: Sun, 7 Oct 2001 15:06:09 -0400
- Cc: Diego Novillo <dnovillo at redhat dot com>, gcc at gcc dot gnu dot org
>> In tree SSA we call calculate_dominance_info and
>> compute_dominance_frontiers directly. Also, the code uses
>> sbitmaps quite frequently. The bitmaps are typically
>> O(n_basic_blocks). What problem are you referring to?
> The bitmaps are probably sparse,
Dominance frontiers have to be sparse.
> and n_basic_blocks can blow up, at
> which point your memory usage blows up too. Brad Lucier has some good
> examples of this problem.
Yes, but i'm taking care of this, so no worries.
Without ssa even enabled, the new bitmaps i'm performance tuning
(still), saves about 30% memory over current bitmaps.
For instance, compiling one file (I can't remember if it's expr.c or
20001226-1.c, i forget at the moment) at -O2 normally takes 130 meg,
peak. It now takes 100 meg, peak.
This is without modifying anything to use sparse bitmaps, just replacing
the existing bitmap implementation.