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Re: needless deep recursion in gt-c-decl.h


> Date: Mon, 05 Aug 2002 11:43:17 -0700
> From: Per Bothner <per@bothner.com>

> Geoff Keating wrote:
> > The slowdown appears to be in using a two-loop algorithm for marking
> > RTL, not in marking trees or in the third loop.
> 
> I'm point point is I'm not sure a two-loop algorithm is needed.
> I got the impression is that the one-loop argorithm doesn't work
> for trees because of references from trees to rtl, like DECL_RTL.
> I don't understand how rtl to the same extent, but I also think
> a single loop should be enough to avoid deep recursion.

That case was an example of how even the two-loop algorithm doesn't
work.  I think I described in a previous e-mail how the one-loop
algorithm doesn't work; IIRC it went like:

originally: 24000 maximum nesting on expr.o
one loop: 16000
two loops: 9000
three loops: 800

> I'm just concerned about slowing down gcc bit by bit.

Annoying, but there seems little choice.

-- 
- Geoffrey Keating <geoffk@geoffk.org> <geoffk@redhat.com>


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