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Re: [patch] cse.c: Speed up delete_trivially_dead_insns.
- From: Jeffrey A Law <law at redhat dot com>
- To: Kazu Hirata <kazu at cs dot umass dot edu>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 31 Jan 2005 15:26:19 -0700
- Subject: Re: [patch] cse.c: Speed up delete_trivially_dead_insns.
- Organization: Red Hat, Inc
- References: <email@example.com>
- Reply-to: law at redhat dot com
On Mon, 2005-01-31 at 08:30 -0500, Kazu Hirata wrote:
> Attached is a patch to speed up delete_trivially_dead_insns by not
> On mainline, we do a lot of work on constant propagation, DCE, and DOM
> among other things, so delete_trivially_dead_insns does not have as
> many opportunities to remove insns. Here are some numbers obtained
> while compiling cc1-i files.
[ ... ]
FWIW, I can speculate on ways to get dead code past the SSA optimizers
in such a way as to require iteration from delete_trivially_dead_insns.
However, they would be pretty convoluted testcases. I suspect that such
code is already exceedingly rare in practice and will only become rarer
still as the SSA optimizers continue to improve.