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Re: [dataflow] [RFC] Remove many almost useless DCE passes
- From: "Steven Bosscher" <stevenb dot gcc at gmail dot com>
- To: "Paolo Bonzini" <paolo dot bonzini at lu dot unisi dot ch>
- Cc: "GCC Patches" <gcc-patches at gcc dot gnu dot org>, "Kenneth Zadeck" <zadeck at naturalbridge dot com>
- Date: Tue, 27 Feb 2007 08:23:52 +0100
- Subject: Re: [dataflow] [RFC] Remove many almost useless DCE passes
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- References: <45E3D856.1030007@lu.unisi.ch>
On 2/27/07, Paolo Bonzini <paolo.bonzini@lu.unisi.ch> wrote:
Kenny, does this seem sensible? Steven, do you have different numbers
or do you see something wrong in the patch?
First of all, I think this is too aggressive.
I know for example that your cfgcleanup.c changes (which are not
properly documented in the ChangeLog, btw) will cause us to miss many
optimizations (in particular, crossjumping -- we already have PRs
showing this is a problem on the dataflow branch).
I'd also think that we have to be careful that we do not make it too
hard for ourselves to re-order RTL passes and to interpret dump files.
Both are harder with your approach. I'd be perfectly happy to
sacrifice 0.5% of compile time for a more/easier maintainable
compiler.
Gr.
Steven