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Re: Loop Invariance Optimization Opportunity?

From Wojtek Lerch <wojtek_l@yahoo.ca>
Newsgroups comp.std.c
Subject Re: Loop Invariance Optimization Opportunity?
Date 2013-01-18 12:25 -0500
Message-ID <altersFe0nnU1@mid.individual.net> (permalink)
References <kdbifk$nhb$1@dont-email.me>

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On 18-Jan-13 8:25 AM, Shao Miller wrote:
> GCC without an -O, with -O2, and with -O3 didn't make any difference in
> the behaviour.  If an invariance optimization is used, the loop should
> iterate 42 times, instead of 21.

Have you tried you moving "looper" into a separate translation unit?

I'm getting 42 with GCC 4.4.2, but 21 with GCC 4.6.3.

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Thread

Loop Invariance Optimization Opportunity? Shao Miller <sha0.miller@gmail.com> - 2013-01-18 08:25 -0500
  Re: Loop Invariance Optimization Opportunity? Wojtek Lerch <wojtek_l@yahoo.ca> - 2013-01-18 12:25 -0500
    Re: Loop Invariance Optimization Opportunity? Shao Miller <sha0.miller@gmail.com> - 2013-01-18 15:36 -0500
      Re: Loop Invariance Optimization Opportunity? Shao Miller <sha0.miller@gmail.com> - 2013-01-21 00:43 -0500

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