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Re: user-guided speculative precomputation? (my wacky ia64 idea)
- From: Jim Wilson <wilson at specifixinc dot com>
- To: Duraid Madina <duraid at octopus dot com dot au>
- Cc: gcc at gcc dot gnu dot org
- Date: Mon, 05 Apr 2004 23:02:13 -0700
- Subject: Re: user-guided speculative precomputation? (my wacky ia64 idea)
- References: <406B5D18.7080605@octopus.com.au>
Duraid Madina wrote:
tricky to do this automatically, but my question to the group is: would
it be sensible to add support for something like a "#pragma
delinquent_load" that could be inserted at the appropriate point in e.g.
graph/tree/list traversal code etc.? A "cookie cutter" prefetching
sequence could then be fitted in the reserved area alongside the main
thread
You didn't define what #pragma delinquent_load does, and I don't have a
copy of that paper.
Probably you would have to try to implement it before you can tell
whether you can make it work.
The limited number of bundle formats makes it difficult to reserve an
issue slot. You will get differing types of left-over slots depending
on what instructions from the main thread get scheduled, and you will
have differing types of insns that need to fit into those slots. This
could lead to a difficult packing problem. And there is also the issue
of stop bits.
--
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com