[Boost-bugs] [Boost C++ Libraries] #3341: sp_counted_base_gcc_sparc.hpp compile failure on gcc.4.2.3 w/-O2

Subject: [Boost-bugs] [Boost C++ Libraries] #3341: sp_counted_base_gcc_sparc.hpp compile failure on gcc.4.2.3 w/-O2
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-08-13 19:20:12

#3341: sp_counted_base_gcc_sparc.hpp compile failure on gcc.4.2.3 w/-O2
---------------------------------------+------------------------------------
 Reporter:  jon_p_griffiths@…          |       Owner:  pdimov   
     Type:  Bugs                       |      Status:  new      
Milestone:  Boost 1.40.0               |   Component:  smart_ptr
  Version:  Boost 1.39.0               |    Severity:  Problem  
 Keywords:  gcc, CAS, sp_counted_base  |  
---------------------------------------+------------------------------------
 compare_and_swap() from sp_counted_base_gcc_sparc.hpp fails to compile
 here with gcc 4.2.3 configured thusly:

 -bash-3.00$ /opt/gcc-4.2.3/bin/g++ -v
 Using built-in specs.
 Target: sparc64-sun-solaris2.10
 Configured with: ../src/configure --host=sparc64-sun-solaris2.10 --with-
 gnu-as --with-as=/opt/binutils-2.17/bin/as --with-gnu-ld --with-
 ld=/opt/binutils-2.17/bin/ld --with-pic --enable-languages=c,c++
 --prefix=/opt/gcc-4.2.3
 Thread model: posix
 gcc version 4.2.3

 The problem is the "=m" asm constraint in this function, which allows
 memory references of any form. When compiling with optimisation, gcc
 avoids some address math and ends up emitting <reg>+<offset> for the first
 operand in its inlined call. 'as' then refuses to assemble this ('Illegal
 Operands'). If the function is not inlined, the dest_ parameter has the
 offset added to it before being passed to the function and it then
 compiles quite happily. Unfortunately, gcc does not have an asm constraint
 to specify that offsets should not be used in memory references.

 I'm working around this locally by making the function static and
 attribute(noinline), which works with a small code size cost. An alternate
 fix would be to load the memory address from another register in the asm
 expression, but that's beyond my gcc asm-fu.

 Alternately, this may be considered a bug in the compiler - but adding the
 missing constraint is more likely to be considered a feature request IMO,
 hence the bug report here first.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3341>
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