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Re: merging for 3.4 (was Re: [Patch] Qualify min(), max() ...)
- From: Daniel Berlin <dberlin at dberlin dot org>
- To: Neil Booth <neil at daikokuya dot co dot uk>
- Cc: Jan Hubicka <hubicka at ucw dot cz>, Joe Buck <jbuck at synopsys dot com>,Diego Novillo <dnovillo at redhat dot com>,Mark Mitchell <mark at codesourcery dot com>,Benjamin Kosnik <bkoz at redhat dot com>,Gabriel Dos Reis <gdr at integrable-solutions dot net>,"pcarlini at unitus dot it" <pcarlini at unitus dot it>,"libstdc++ at gcc dot gnu dot org" <libstdc++ at gcc dot gnu dot org>, "" <gcc at gcc dot gnu dot org>
- Date: Wed, 4 Dec 2002 17:23:40 -0500 (EST)
- Subject: Re: merging for 3.4 (was Re: [Patch] Qualify min(), max() ...)
- References: <20021204194110.GA13428@tornado.toronto.redhat.com><200212042054.gB4Ksb008847@piper.synopsys.com> <20021204210809.GO5173@kam.mff.cuni.cz><20021204213956.GD3050@daikokuya.co.uk>
On Wed, 4 Dec 2002, Neil Booth wrote:
> Jan Hubicka wrote:-
>
> > Compiler is getting slower in each release but that is mostly cumulative
> > result of adding new features current infrastructure can't accept
> > cheaply...
>
> I hate this slowness. There's no reason IMO that GCC couldn't be 4
> times faster than it is, without any PCH or anything. A lot of the
> code we use is just awfully inefficient. And people are working on
> more interesting things than fixing some of the real problems we have.
This is one of the very reasons for tree-ssa. So we can do most of the
slow crap we do in the backend (attempts at high level loop optimizations,
etc), in the frontend at a reasonable speed with good algorithms (it's
hard to do at reasonable speed in the backend because we end up trying to
recreate info we already have).
Most compiler backends consist mainly of cheap optimizations, register
allocation, and scheduling.
That's it.
> There's no excuse for the parser taking more time than CPP for example;
> currently it takes about 4-5 times as long. I want to see GCC so fast
> that CPP is up to 5-10% of CPU time. It's rarely much above 1 or 2%.
>
> Neil.
>