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Re: bitmaps in gcc

From: Ian Lance Taylor <ian at airs dot com>
To: Brian Makin <merimus at yahoo dot com>
Cc: gcc at gcc dot gnu dot org
Date: 14 Oct 2005 11:40:21 -0700
Subject: Re: bitmaps in gcc
References: <20051014182715.47814.qmail@web36108.mail.mud.yahoo.com>

Brian Makin <merimus@yahoo.com> writes:

> Bitmaps, also called sparse bit sets, are implemented
> using a linked list with a cache. This is probably not
> the most time-efficient representation, and it is not
> unusual for bitmap functions to show up high on the
> execution profile. Bitmaps are used for many things,
> such as for live register sets at the entry and exit
> of basic blocks in RTL, or for a great number of data
> flow problems. See bitmap.c (and sbitmap.c for GCC's
> simple bitmap implementation).
> 
> Can someone point me to a testcase where bitmap
> functions show up high on the profile?

PR 8361.

Ian

References:
- bitmaps in gcc
  - From: Brian Makin

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