Re: [Boost-bugs] [Boost C++ Libraries] #9233: Suboptimal shift by multiples of 8 bits

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #9233: Suboptimal shift by multiples of 8 bits
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-02-18 11:36:34

#9233: Suboptimal shift by multiples of 8 bits
-------------------------------+----------------------------
  Reporter:  psiha             |      Owner:  johnmaddock
      Type:  Bugs              |     Status:  closed
 Milestone:  To Be Determined  |  Component:  multiprecision
   Version:  Boost 1.54.0      |   Severity:  Optimization
Resolution:  wontfix           |   Keywords:
-------------------------------+----------------------------

Comment (by psiha):

 Maybe you could add/separate specialized functions for shifting: for whole
 limbs, for whole bytes and 'generic'. Then the shift operator can be
 implemented as
 if ( bits % limb_bits == 0 ) shift_limbs();
 elseif ( bits % 8 == 0 ) shift_bytes();
 else { generic() };
 and rely on IPO to directly select the optimal implementation when bits is
 a compile time constant...

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/9233#comment:2>
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