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Re: Should -fcross-jumping be part of -O1?

From: Robert Dewar <dewar at gnat dot com>
To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
Cc: gcc at gcc dot gnu dot org
Date: Wed, 03 Dec 2003 11:11:55 -0500
Subject: Re: Should -fcross-jumping be part of -O1?
References: <10312031545.AA13875@vlsi1.ultra.nyu.edu>

Richard Kenner wrote:

    Well as part of this thought experiment, please consider that if each
    of these five axes has three settings, then there are 3**5
    combinations, which is a large number, and of course there is no
    possibility of the compiler behaving in 3**5 significantly different ways.

Right now, I count about 20 different optimizations switches and
2**20 is significantly larger than 3**5!


That's not the right comparison. If you go this route, then you need a
manual that for each of the 243 combinations of optimziation swithces
tells you which of these 2**20 possibilities applies to that combination.

Sounds like a mess to me (actually I count more than 20 optimziation options :-)

References:
- Re: Should -fcross-jumping be part of -O1?
  - From: Richard Kenner

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