Re: [Boost-bugs] [Boost C++ Libraries] #9766: boost >= 1.54 failes to compile with gcc-4.8.2 and LTO enabled

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #9766: boost >= 1.54 failes to compile with gcc-4.8.2 and LTO enabled
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-04-26 17:35:52

#9766: boost >= 1.54 failes to compile with gcc-4.8.2 and LTO enabled
-------------------------------+---------------------
  Reporter:  steffen@…         |      Owner:  andysem
      Type:  Bugs              |     Status:  new
 Milestone:  To Be Determined  |  Component:  log
   Version:  Boost 1.54.0      |   Severity:  Problem
Resolution:                    |   Keywords:
-------------------------------+---------------------

Comment (by andysem):

 After all my experiments I still fail to reproduce the error. I even tried
 to replay the compilation with the command lines from your build log. I've
 discovered one nasty detail though - the resulting binaries in my case are
 AVX2-only. I guess my compiler somehow applies the flags for dump_avx2.cpp
 to all object files. Needless to say that if that's how LTO is supposed to
 work, it cannot be used with projects such as Boost.Log.

 However, I have a patch I'd like to test. Basically, it adds attributes to
 all SSE/AVX functions so that the compiler knows what CPU they are
 targeted for. I'd appreciate if you could perform the following
 experiment:

 1. Apply the patch from this ticket.
 2. Perform a clean rebuild of Boost.
 3. If Boost.Log compiles this time, run the following command:

 {{{
 objdump -dS libboost_log.so.1.55.0 >libboost_log.so.1.55.0.S
 }}}

 (add the directory name to the compiled library, if necessary).
 4. Compress libboost_log.so.1.55.0.S and attach it to this ticket.

 The libboost_log.so.1.55.0.S is the disassembled library; I'd like to
 inspect the resulting code for whether it's AVX2-only or not.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/9766#comment:10>
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