From: Nathan Sidwell <nathan@codesourcery.com>
To: Mark Mitchell <mark@codesourcery.com>
Cc: Gabriel Dos Reis <gdr@codesourcery.com>,
Jason Merrill <jason@redhat.com>,
Richard Henderson <rth@redhat.com>,
"gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Subject: Re: [tree-ssa] Simplifying TARGET_EXPR
Date: Mon, 22 Jul 2002 12:33:00 -0000 [thread overview]
Message-ID: <3D3C1231.2F39DDC@codesourcery.com> (raw)
In-Reply-To: <52110000.1027288471@warlock.codesourcery.com>
Mark Mitchell wrote:
> Maybe I'm developing an unhealthy paranoia. On the one hand,
> optimizing away more copy constructors is like optimizinga away
> more copies between scalars, and I'm all for having -O2 do more
> of that! On the other, copy constructor elision is observable
> behavior in the program, and it's going to make it hard to do
> debug, profile, and otherwise analyze your program if the number
> of copy constructor calls changes when you optimize.
I disagree. Alias analysis makes optimized broken programs hard
to debug, I\x13 don't see why temporary elision is any different..
Maybe have the elision separately disablable at -O2, but I think
it should be permissable.
nathan
--
Dr Nathan Sidwell :: http://www.codesourcery.com :: CodeSourcery LLC
'But that's a lie.' - 'Yes it is. What's your point?'
nathan@codesourcery.com : http://www.cs.bris.ac.uk/~nathan/ : nathan@acm.org
next prev parent reply other threads:[~2002-07-22 14:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-07-20 18:54 Jason Merrill
2002-07-21 0:41 ` Richard Henderson
2002-07-26 14:51 ` PATCH " Jason Merrill
2002-07-21 17:32 ` [tree-ssa] " Mark Mitchell
2002-07-21 18:04 ` Gabriel Dos Reis
2002-07-21 18:14 ` Mark Mitchell
2002-07-21 20:39 ` Gabriel Dos Reis
2002-07-22 8:32 ` Michael Matz
2002-07-22 12:02 ` Gabriel Dos Reis
2002-07-24 3:22 ` Mark Mitchell
2002-07-22 12:33 ` Nathan Sidwell [this message]
2002-07-22 12:53 ` Gabriel Dos Reis
2002-07-22 13:10 ` Jason Merrill
2002-07-21 22:35 ` Jason Merrill
-- strict thread matches above, loose matches on Subject: below --
2002-07-16 9:52 Jason Merrill
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