Re: [rtl-optimization] Improve Data Prefetch for IA-64

[Steven Bosscher <stevenb at suse dot de>]

On Saturday 26 March 2005 02:22, Canqun Yang wrote:
> ÂÂÂÂÂÂÂÂ* loop.c (PREFETCH_BLOCKS_BEFORE_LOOP_MAX): Defined conditionally.
> ÂÂÂÂÂÂÂÂ(scan_loop): Change extra_size from 16 to 128.
> ÂÂÂÂÂÂÂÂ(emit_prefetch_instructions): Don't ignore all prefetches within
> loop.

OK, so I know this is not a popular subject, but can we *please* stop
working on loop.c and focus on getting the new RTL and tree loop passes
to do what we want?  All this loop.c patching is a typical example of
why free software development does not always work: always going for
the low-hanging fruit.  In this case, there have been several attempts
to replace the prefetching stuff in loop.c with something better.  On
the rtl-opt branch there is a new RTL loop-prefetch.c, and on the LNO
branch there is a re-use analysis based prefetching pass.  Why don't
you try to finish and improve those passes, instead of making it yet
again harder to remove loop.c.  This one file is a *huge* problem for
just about the entire RTL optimizer path.  It is, for example, the
reason why there is no profile information available before this old
piece of, if I may say, junk runs, and it the only reason why a great
many functions in for example jump.c and the various cfg*.c files can
still not be removed.

Gr.
Steven