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Re: -O0 dead code
- To: Richard Henderson <rth at cygnus dot com>
- Subject: Re: -O0 dead code
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Tue, 08 Aug 2000 09:15:59 -0600
- cc: gcc at gcc dot gnu dot org
- Reply-To: law at cygnus dot com
In message <20000808005643.A6080@cygnus.com>you write:
> So how do people feel about the notion of dead code elimination at -O0?
> If we exclude the bits that that detect dead stores, we shouldn't be
> affecting any user-visible state, since all user variables live in
> memory at -O0.
>
> It shouldn't (though I've not checked) take any more compile time than
> we're using now, since flow1 is used to collect lifetimes for register
> allocation. Normal dead code elimination happens concurrent to that.
Sounds good to me. I've always been a believer in generating unoptimized
code, not stupid code at -O0 :-)
jeff