From: kenner@vlsi1.ultra.nyu.edu (Richard Kenner)
To: zack@codesourcery.com
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [patch] for PR 18040
Date: Mon, 18 Oct 2004 02:38:00 -0000 [thread overview]
Message-ID: <10410180238.AA02258@vlsi1.ultra.nyu.edu> (raw)
Hmm. Is it possible to construct an example which BOTH requires
taking the address of an intermediate field, and wouldn't be cured by
making all *_REF expressions implicitly convert to their type?
Sorry, I didn't realize that you were talking about a different solutions
to each problem.
I believe the answer to the question you pose is "no", but it's going to be
hard to prove that. There is a potential aliasing problem, but I don't think
it can actually occur because you can always view the semantics of the
VIEW_CONVERT_EXPR as being pointer punning and could make the resulting
pointer TYPE_REF_CAN_ALIAS_ALL.
What I'm not sure about are issues relating to code quality: we've taken what
used to be expanded as one operation between tree and RTL and converted it
into four distinct operations (ADDR_EXPR, NOP_EXPR, INDIRECT_REF, and
COMPONENT_REF) and it'll be up to the RTL optimizers to put it all back
together.
I think it's taking a step backwards when we can no longer represent what
is a single expansion operation in GIMPLE as one statement.
next reply other threads:[~2004-10-18 2:35 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-18 2:38 Richard Kenner [this message]
2004-10-18 3:14 ` Zack Weinberg
-- strict thread matches above, loose matches on Subject: below --
2004-10-20 13:27 Richard Kenner
2004-10-20 0:25 Richard Kenner
2004-10-19 23:26 Richard Kenner
2004-10-19 23:22 Richard Kenner
2004-10-19 23:03 Richard Kenner
2004-10-19 23:13 ` Jason Merrill
2004-10-19 22:48 Richard Kenner
2004-10-19 23:01 ` Jason Merrill
2004-10-19 23:07 ` Zack Weinberg
2004-10-18 17:48 Richard Kenner
2004-10-18 15:42 Richard Kenner
2004-10-18 14:52 Richard Kenner
2004-10-18 15:20 ` Daniel Berlin
2004-10-18 14:38 Richard Kenner
2004-10-18 14:24 Richard Kenner
2004-10-19 22:50 ` Zack Weinberg
2004-10-18 14:22 Richard Kenner
2004-10-19 22:47 ` Zack Weinberg
2004-10-18 3:12 Richard Kenner
2004-10-18 4:02 ` Zack Weinberg
2004-10-18 4:26 ` Daniel Berlin
2004-10-18 2:46 Richard Kenner
2004-10-18 2:35 Richard Kenner
2004-10-18 2:51 ` Zack Weinberg
2004-10-17 23:06 Richard Kenner
2004-10-17 23:45 ` Zack Weinberg
2004-10-18 0:23 ` Zack Weinberg
2004-10-17 22:30 Richard Kenner
2004-10-17 22:36 ` Andrew Pinski
2004-10-17 23:41 ` Zack Weinberg
2004-10-18 13:13 ` Florian Weimer
2004-10-18 17:24 ` Jason Merrill
2004-10-18 17:37 ` Florian Weimer
2004-10-18 18:02 ` Jason Merrill
2004-10-19 22:40 ` Zack Weinberg
2004-10-17 21:24 Richard Kenner
2004-10-17 21:43 ` Zack Weinberg
2004-10-17 21:18 Richard Kenner
2004-10-17 21:26 ` Zack Weinberg
2004-10-17 21:04 Richard Kenner
2004-10-17 21:10 ` Zack Weinberg
2004-10-19 21:36 ` Richard Henderson
2004-10-19 22:19 ` Daniel Berlin
2004-10-20 7:03 ` Jason Merrill
2004-10-19 22:51 ` Zack Weinberg
2004-10-20 0:02 ` Richard Henderson
2004-10-17 20:25 Richard Kenner
2004-10-17 20:47 ` Daniel Berlin
2004-10-17 20:17 Richard Kenner
2004-10-17 20:25 ` Daniel Berlin
2004-10-17 19:46 Richard Kenner
2004-10-17 19:46 ` Daniel Berlin
2004-10-17 19:48 ` Zdenek Dvorak
2004-10-17 20:01 ` Daniel Berlin
2004-10-17 19:28 Zdenek Dvorak
2004-10-19 21:36 ` Richard Henderson
2004-10-19 22:03 ` Zdenek Dvorak
2004-10-19 22:04 ` Andrew Pinski
2004-10-19 22:06 ` Zdenek Dvorak
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