Re: [Boost-bugs] [Boost C++ Libraries] #7272: win32/thread_primitives.hpp: (Unneccessary) Warning

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #7272: win32/thread_primitives.hpp: (Unneccessary) Warning
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-09-28 21:37:33

#7272: win32/thread_primitives.hpp: (Unneccessary) Warning
-----------------------------------------+----------------------------------
  Reporter:  christian.buss@…            |       Owner:  viboes  
      Type:  Patches                     |      Status:  reopened
 Milestone:  Boost 1.52.0                |   Component:  thread  
   Version:  Boost 1.51.0                |    Severity:  Problem 
Resolution:                              |    Keywords:          
-----------------------------------------+----------------------------------
Changes (by gix):

  * status:  closed => reopened
  * resolution:  fixed =>
  * severity:  Cosmetic => Problem

Comment:

 The warning reported by ICL points at a serious bug. Changesets [80203]
 and [80235] only silence the warning.

 ICL seems to only accept newlines as separator between asm instructions
 and only emits "mov eax,bit", which makes interlocked_bit_test_and_set
 return an ret uninitialized.

 Running the attached test case:
 {{{
 $ icl -nologo -EHsc boost-7272.cpp && boost-7272.exe
 boost-7272.cpp
 Testing bit 0 of x=3
 result: 0 (expected: 1)
 x:      3 (expected: 3)
 Testing bit 2 of x=3
 result: 0 (expected: 0)
 x:      3 (expected: 7)
 }}}

 As a comparison, here with MSVC:
 {{{
 D:\>cl -nologo -EHsc boost-7272.cpp && boost-7272.exe
 boost-7272.cpp
 Testing bit 0 of x=3
 result: 1 (expected: 1)
 x:      3 (expected: 3)
 Testing bit 2 of x=3
 result: 0 (expected: 0)
 x:      7 (expected: 7)
 }}}

 Putting each instruction on a separate line (with and without trailing
 ";") fixes this.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7272#comment:6>
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