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Re: [PATCH]: Efficient sbitmap based bitset
- To: Matt Kraai <kraai at alumni dot carnegiemellon dot edu>
- Subject: Re: [PATCH]: Efficient sbitmap based bitset
- From: Daniel Berlin <dan at cgsoftware dot com>
- Date: Mon, 20 Aug 2001 12:58:10 -0400
- Cc: Daniel Berlin <dan at cgsoftware dot com>, gcc-patches at gcc dot gnu dot org
- References: <20010820085556.A24326@opensource.lineo.com>
Matt Kraai <kraai@alumni.carnegiemellon.edu> writes:
> Howdy,
>
> I have two questions about your patch.
>
>> + /* Copy the ebitmap at FROM into the ebitmap at TO */
>> + void
>> + ebitmap_copy (to, from)
>> + ebitmap to;
>> + ebitmap from;
>> + {
>> + unsigned int i;
>> + ebitmap_clear (to);
>> + ebitmap_free_if_shrink (to, VARRAY_SIZE (to->array),
>> + VARRAY_SIZE (from->array));
>
> Why do you need to call ebitmap_free_if_shrink after calling
> ebitmap_clear?
You don't.
I was cut and pasting.
>
> Also, in the ebitmap_a_OP_b family of functions, does the return
> value need to be accurate, or is it just a hint?
Accurate, or conservative (IE saying it's changed when it might not have is
okay, as long as we don't *always* say it's changed when it hasn't.)
It's used in iterative dataflow to determine when the solution has
stopped changing.
>
> Matt
--
"I'm so hyper... (Said with a very dull voice.)
"-Steven Wright