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Re: [tree-ssa] More aggressive dead code elimination
- From: Steven Bosscher <s dot bosscher at student dot tudelft dot nl>
- To: law at redhat dot com
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 8 Jan 2004 00:15:20 +0100
- Subject: Re: [tree-ssa] More aggressive dead code elimination
- References: <200401072305.i07N5nIJ032299@speedy.slc.redhat.com>
On Thursday 08 January 2004 00:05, law@redhat.com wrote:
> In message <200401072356.14021.s.bosscher@student.tudelft.nl>, Steven
> Bosscher
>
> writes:
> >> 2. If the last DCE pass kills a conditional it does not arrange to
> >> kill the statements which feed the conditional. This can be
> >> easily solved by re-running the DCE pass in that case. These are
> >> extremely rare.
> >
> >Running the existing DCE twice is just as expensive as running the more
> >aggressive version just once, so this argument doesn't make sense to me.
>
> Err, not for big functions. And remember the cases where we would need
> to do this are extremely rare.
Well perhaps I'm a complete moron, but I don't see what function size has to
do with it. Both algorithms are linear in the number of statements.
Gr.
Steven