Re: [Boost-bugs] [Boost C++ Libraries] #11989: gcc 5.3 optimizer mangles non_blocking_recvfrom

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #11989: gcc 5.3 optimizer mangles non_blocking_recvfrom
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-02-23 11:35:16

#11989: gcc 5.3 optimizer mangles non_blocking_recvfrom
-------------------------------+----------------------------
  Reporter:  tmark@…           |      Owner:  chris_kohlhoff
      Type:  Bugs              |     Status:  new
 Milestone:  To Be Determined  |  Component:  asio
   Version:  Boost 1.58.0      |   Severity:  Optimization
Resolution:                    |   Keywords:
-------------------------------+----------------------------

Comment (by tmark@…):

 After further analysis we've discovered that the optimizer does not remove
 the tests, it alters the comparison of  (ec == enumerated value).   If one
 replaces the "ec" with "ec.value()" in the expressions, such that you are
 explicitly comparing the interger error value the code works correctly
 when optimized:

 {{{
      :

     // Retry operation if interrupted by signal.
     if (ec.value() == boost::asio::error::interrupted)
       continue;

     // Check if we need to run the operation again.
     if (ec.value() == boost::asio::error::would_block
         || ec.value() == boost::asio::error::try_again)
       return false;

      :
 }}}

 Alternatively, adding an inline operator:

 {{{
       inline friend bool operator==( const error_code & lhs,
                                      const int & rhs )
 BOOST_SYSTEM_NOEXCEPT
       {
         return lhs.m_val == rhs;
       }
 }}}

 to error_code class also cures the issue.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11989#comment:1>
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