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Re: [tree-ssa] Improve memory characteristics of VDEFs
- From: Gerald Pfeifer <gp at suse dot de>
- To: Jeffrey Law <law at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 24 Nov 2003 11:06:19 +0100 (CET)
- Subject: Re: [tree-ssa] Improve memory characteristics of VDEFs
- References: <200311212023.hALKNZgU001123@speedy.slc.redhat.com>
On Fri, 21 Nov 2003 law@redhat.com wrote:
> Based on Steven's data, we generate somewhere around 325000 VDEF_EXPRs
> for PR8361. That means there's several megabytes of wasted memory as well
> as 325000 nodes the GC system needs to manage which are really totally
> unnecessary.
Ugh.
> A more efficient scheme is to imply make the VDEFs into a varray which
> stores pairs of trees. The first is the result, the second is the source
> [ We already had a varray for vdefs -- the varray used to store the VDEF_EXPR.
> ]
>
> This is quite a bit more efficient in terms of memory utilization and GC
> tracking and prodes a nice little speedup on PR8361, will a very small
> positive impact on the more general cc1 components test.
>
> If you look at the number of EXPR nodes we generate before/after this
> patch on PR8361 you'll see a significant decrease in both the number of
> nodes as well as the amount of memory consumed by those nodes.
Cool, thanks! Do you happen to still have the numbers (before-after)
somewhere?
Gerald