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Re: [PATCH]: Efficient sbitmap based bitset
- To: Daniel Berlin <dan at cgsoftware dot com>
- Subject: Re: [PATCH]: Efficient sbitmap based bitset
- From: Richard Henderson <rth at redhat dot com>
- Date: Sun, 19 Aug 2001 22:41:40 -0700
- Cc: gcc-patches at gcc dot gnu dot org
- References: <87r8u77seg.fsf@cgsoftware.com>
On Sun, Aug 19, 2001 at 03:37:27PM -0400, Daniel Berlin wrote:
> Using this in df.c instead of bitmaps makes it a lot faster, yet uses
> comparable memory.
On the face of it, this looks pretty reasonable. I'd prefer
to see it be a complete replacement for bitmap. That would
either require obstacking this implementation (ick) or fixing
the users of bitmap and make them clean up after themselves.
I also wonder if better memory density could be had by doing
some by-hand memory allocation. That is, N 64 byte blocks of
memory can be allocated out of raw pages without overhead,
whereas you'll waste at least 2 pointer's worth with malloc.
r~