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Re: [PATCH][RFC] Radically simplify emission of balanced tree for switch statements.
- From: Bernhard Reutner-Fischer <rep dot dot dot nop at gmail dot com>
- To: gcc-patches at gcc dot gnu dot org,Martin Liška <mliska at suse dot cz>,Richard Biener <richard dot guenther at gmail dot com>,Jeff Law <law at redhat dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 15 Jan 2018 00:22:47 +0100
- Subject: Re: [PATCH][RFC] Radically simplify emission of balanced tree for switch statements.
- Authentication-results: sourceware.org; auth=none
- References: <4a6e1c28-6a18-0084-e602-57a0c259d676@suse.cz> <c0fc51df-4794-be1e-e139-578464623e57@redhat.com> <a385e3cb-4a33-55ea-5c3b-1d159a040cf0@suse.cz> <a6cb6f37-da62-5a8f-252a-e23adaab9757@redhat.com> <61dae28e-d66c-c9e0-5c6b-cb5729c5ce64@suse.cz> <9bf4bd49-2587-e6d9-dab3-64c86d936890@redhat.com> <CAFiYyc1vvmNxo0y=-y4eLg6Sz3rwzYsFaB85g2N8rt16iwgRMA@mail.gmail.com> <0a8e5ff4-9a1f-54d4-9a90-a0e27eb4c226@suse.cz>
On 10 January 2018 15:59:28 CET, "Martin Liška" <mliska@suse.cz> wrote:
>On 01/10/2018 02:13 PM, Richard Biener wrote:
>> On Tue, Jan 9, 2018 at 7:29 PM, Jeff Law <law@redhat.com> wrote:
>>> On 01/09/2018 07:43 AM, Martin Liška wrote:
>>>> On 09/20/2017 05:00 PM, Jeff Law wrote:
>>>>> On 09/20/2017 01:24 AM, Martin Liška wrote:
>>>>>
>>>>>>
>>>>>> Hello.
>>>>>>
>>>>>> Thank you Jeff for very verbose explanation what's happening. I'm
>planning to do
>>>>>> follow-up of this patch that will include clustering for
>bit-tests and jump tables.
>>>>>> Maybe that will make aforementioned issues even more difficult,
>but we'll see.
>>>>> FWIW, the DOM changes to simplify the conditionals seem to help
>both
>>>>> cases, trigger reasonably consistently in a bootstrap and for some
>>>>> subset of the triggers actually result in transformations that
>allow
>>>>> other passes to do a better job in the common (-O2) case. So my
>>>>> inclination is to polish them a bit further get them on the trunk.
>>>>>
>>>>> My recommendation is to ignore the two regressions for now and
>focus on
>>>>> the cleanups you're trying to do.
>>>>>
>>>>> jeff
>>>>>
>>>>
>>>> Hello.
>>>>
>>>> Some time ago I've decided that I'll make patch submission of
>switch clustering
>>>> in next stage1. However, this patch can be applied as is in this
>stage3. Would
>>>> it be possible or is it too late?
>>> I'll let Richi make the call here. FWIW, the DOM changes to avoid
>the
>>> two missed-optimization regressions you ran into are on the trunk,
>so
>>> that's no longer a blocking issue.
>>
>> If you are fine with waiting then please wait ;)
>
>Yep, it's not urgent.
Can you please post CSiBE numbers? Ideally throwing in gcc-3.4.6 numbers too?
thanks,