------- Comment #20 from law at redhat dot com 2006-04-13 18:14 -------
Subject: Re: VRP/DOM does not like
TRUTH_AND_EXPR
On Fri, 2006-04-07 at 12:23 +0000, rguenth at gcc dot gnu dot org wrote:
>
> ------- Comment #19 from rguenth at gcc dot gnu dot org 2006-04-07 12:23
> -------
> Jeff, can you send me the patch-in-progress you have for this? Thanks.
Sorry. Surgery and been on the road.
Here's what I've been playing with -- I'm not happy with its structure
yet, but should give you a rough idea of what I've been playing with.
In terms of simplifying conditionals -- the improvements are trivial.
Astoundingly trivial. We also see a small increase in the number of
jumps threaded and blocks merged.
Measuring the number of blocks removed isn't particularly interesting
as we'll count blocks which were created solely to hold ASSERT_EXPRs,
then became trivial forwarders once we removed the ASSERT_EXPRs.
Given the very small improvements we're definitely going to need to
look very closely at the compile-time impact of these changes. We may
have a case where the compile-time impact is greater than the runtime
benefits.
The TRUTH_NOT_EXPR stuff doesn't trigger in my test bucket, probably
because I don't have many FP tests. FP stuff is about the only time
I can think of that we'd fail inverting the tense of a comparison and
have to fall back to TRUTH_NOT_EXPR.
I haven't done any bootstrap or regression testing with this patch.
------- Comment #21 from law at redhat dot com 2006-04-13 18:14 -------
Created an attachment (id=11259)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11259&action=view)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15911
