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Re: [perl #76438] peephole optimiser could prune more dead code

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From:
Reini Urban
Date:
July 15, 2010 04:46
Subject:
Re: [perl #76438] peephole optimiser could prune more dead code
Message ID:
AANLkTimOCNo7GsrX3hjFIaDE5Ft1SewvVtAfO8Vi0HvS@mail.gmail.com
2010/7/15 Dave Mitchell <davem@iabyn.com>:
> On Thu, Jul 15, 2010 at 01:28:58PM +0200, Reini Urban wrote:
>> 2010/7/15 demerphq <demerphq@gmail.com>:
>> > On 15 July 2010 01:12, Dave Mitchell <davem@iabyn.com> wrote:
>> >> On Wed, Jul 14, 2010 at 09:39:35AM +0200, demerphq wrote:
>> >>> Whomever decided that
>> >>>
>> >>>   $a . $a
>> >>>
>> >>> is specified when $a is tied and returns a different value each fetch
>> >>> had forgotten this fact.
>> >>
>> >> You'll have to argue that with Hugo then!
>>
>> I'm also with Yves here.
>> Hugo destroyed language semantics with 5.6.2, if I read the pp_hot.c
>> patch right.
>
> No I think you're reading it the wrong way. Hugo's patch ensures that $a
> is evaluated *twice* in $a.$a.

Great! I see it now in the two gmagic tests.
So I'm not with Yves anymore and nothing needs to be done there.

I still have no time to finish my simple optimizer rule for Nicks
original report, so I attach my latest approach. Maybe someone else
might want to finish and test it. This weekend I'm away
-- 
Reini

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