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Re: [PATCH] Fix CSE bogus RTL creation
- From: Steven Bosscher <stevenb dot gcc at gmail dot com>
- To: Paul Brook <paul at codesourcery dot com>
- Cc: Mark Mitchell <mark at codesourcery dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Paolo Bonzini <bonzini at gnu dot org>
- Date: Fri, 23 Jul 2010 00:17:34 +0200
- Subject: Re: [PATCH] Fix CSE bogus RTL creation
- References: <firstname.lastname@example.org> <4C16BE47.email@example.com> <AANLkTinoWv90ExwsZ4gBivLTGDQwjBx87Lq2RQ0VGgYfirstname.lastname@example.org> <4C178976.email@example.com> <4C179D14.firstname.lastname@example.org>
On Tue, Jun 15, 2010 at 5:32 PM, Paolo Bonzini <email@example.com> wrote:
> On 06/15/2010 04:08 PM, Mark Mitchell wrote:
>> Of course, I am all for superior patches, good infrastructure,
>> clean-ups, and so forth. ?But, it seemed clear to me that (a)
>> validate_change wasn't in the business of making canonical RTL, and
>> (b) simplify_rtx was
> For that matter, canonicalize_change_group also is, and is more directly
> related to validate_change.
>> and (c) this patch made the compiler better from a user-observable
>> point of view, in that it eliminated crashes,
> Without knowing the real bug, you cannot know if there are other
> identical crashes waiting to bite you.
>> and (d) there had been some previous discussion suggesting this
>> I think that should be good enough. ?Now, of course, if you have an
>> idea about how to do it better, I think that's great! ?A more
>> general, more elegant solution would be terrific.
> I gave a patch and Steven outlined another idea that might be even
> better. ?Again, I cannot say if Steven's idea would work without knowing
> what the real bug is.
>> But, I don't want perfect to be the enemy of good.
> But "papering over the real bug" _is_ the enemy of "good". ?That is
> something clearly undesirable, not just suboptimal, especially at the
> beginning of stage1.
> I'm not opposing the patch at all costs, but definitely the bug hasn't
> been analyzed thoroughly enough.
And apparently we're now completely stalled. Paul, are you still
working on this? Is there anything you can file in bugzilla, at least,
so this discussion will not get lost?