Re: [Boost-bugs] [Boost C++ Libraries] #8081: suggestion: avoid using postfix operator++ in transform_width

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #8081: suggestion: avoid using postfix operator++ in transform_width
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-02-25 21:34:12

#8081: suggestion: avoid using postfix operator++ in transform_width
-------------------------------+--------------------------------------------
  Reporter:  jinmei@…          |       Owner:  ramey        
      Type:  Patches           |      Status:  closed       
 Milestone:  To Be Determined  |   Component:  serialization
   Version:  Boost 1.53.0      |    Severity:  Optimization 
Resolution:  invalid           |    Keywords:               
-------------------------------+--------------------------------------------

Comment (by anonymous):

 Replying to [comment:1 ramey]:
 > "use of the postfix version is suboptimal in terms of efficiency"
 >
 > Not in this case.
 >
 > ++i is more efficient that i++
 >
 > but
 > x = i; ++i
 >
 > is NOT more efficient than x = i++.

 True, but that's not what the proposed patch does.  It does:

 x = i.operator*();
 ++i;

 And, if call to operator*() is more lightweight than copying i, it
 should be more efficient than

 x = i.operator*();
 i++;

 which is essentially what the original code does.

 Am I still misunderstanding something?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/8081#comment:2>
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