[Boost-users] Bizarre behaviour with Microsoft compiler

10 Sep 2006

      I have a fraction of code using BGL that the MS compiler has for some reason
optimized into oblivion. While this is not a boost problem per se, since it
appears in a compiler I have not had problems with, I suspect all those
templates are confusing the MS compiler somehow.

The symptom is that when I get a property of an edge, then test on that
property and branch, the test is removed from the compiled assembly.

Here is the code:
//header
typedef property<edge_weight_t, unsigned>
EdgeCountProperty;
typedef adjacency_list<vecS, vecS, bidirectionalS, no_property,
EdgeCountProperty>       Graph;
typedef graph_traits<Graph>::out_edge_iterator
OutEdgeIter;

.....
//code
    property_map<Graph, edge_weight_t>::type wgt = get(edge_weight, g);
    OutEdgeIter ei, ee, eMax;
    unsigned nTopWgt = 0;
    unsigned nChk = 0;
    for(tie(ei, ee) = out_edges(v, g), eMax = ee; ei != ee; ++ei)
    {
        nChk = wgt[*ei];

////////This 'if' is skipped, the code acts like nChk > nTopWgt is always
TRUE, even when it ain't!!
        if(nChk > nTopWgt);
        {
            nTopWgt = nChk;
            eMax = ei;
        }
    }

Here is the assembly:
    OutEdgeIter ei, ee, eMax;
00420514  lea         ecx,[ei]
00420517  call
boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
...
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> > > >::iterator,unsigned
int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,int>::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::e
0042051C  lea         ecx,[ee]
0042051F  call
boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> > > >::iterator,unsigned
int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,int>::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::e
00420524  lea         ecx,[eMax]
00420527  call
boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> > > >::iterator,unsigned
int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,int>::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum boost::e
    unsigned nTopWgt = 0;
0042052C  mov         dword ptr [nTopWgt],0
    unsigned nChk = 0;
00420533  mov         dword ptr [nChk],0
    for(tie(ei, ee) = out_edges(v, g), eMax = ee; ei != ee; ++ei)
0042053A  mov         eax,dword ptr [g]
0042053D  push        eax
0042053E  mov         ecx,dword ptr [v]
00420541  mov         edx,dword ptr [ecx]
00420543  push        edx
00420544  lea         eax,[ebp-198h]
0042054A  push        eax
0042054B  call        @ILT+5420(??$out_edges@Uconfig@?$adj_list_gen@
V?$adjacency_list@UvecS@boost@@U12@UbidirectionalS@2@Uno_property@2@U
?$property@W4edge_weight_t@boost@@IUno_property@2@@2@U42@UlistS@2@@boost@@
UvecS@2@U32@UbidirectionalS@2@Uno_property@2@U?$property@
W4edge_weight_t@boost@@IUno_property@2@@2@U52@UlistS@2@@detail@boost@@
U?$bidirectional_graph_helper_with_property@Uconfig@?$adj_list_gen@
V?$adjacency_list@UvecS@boost@@U12@UbidirectionalS@2@Uno_property@2@U
?$property@W4edge_weight_t@boost@@IUno_property@2@@2@U42@UlistS@2@@boost@@
UvecS@2@U32@UbidirectionalS@2@Uno_property@2@U?$property@
W4edge_weight_t@boost@@IUno_property@2@@2@U52@UlistS@2@@detail@boost
@@@4@@boost@@YA?AU?$pair@U?$out_edge_iter@Viterator@?$vector@
V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@
IU?$property@W4edge_weight_t@boost@@IUno_property@2
@@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@detail@boost@@V?$allocator@
00420550  add         esp,0Ch
00420553  push        eax
00420554  lea         ecx,[ee]
00420557  push        ecx
00420558  lea         edx,[ei]
0042055B  push        edx
0042055C  lea         eax,[ebp-1A8h]
00420562  push        eax
00420563  call        @ILT+4705(??$tie@U?$out_edge_iter@Viterator@?$vector@
V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@
IU?$property@W4edge_weight_t@boost@@IUno_property@2
@@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@detail@boost@@V?$allocator@V
?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@
IU?$property@W4edge_weight_t@boost@@IUno_property@2
@@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@detail@boost@@@std@@@std@@
IV?$edge_desc_impl@Ubidirectional_tag@boost@@I@detail@boost@@H@detail
@boost@@U123@@tuples@boost@@YA?AV?$tuple@AAU
?$out_edge_iter@Viterator@?$vector@V?$sei_@IViterator@?$list@U?$list_edge@IU
?$property@W4edge_weight_t@boost@@IUno_property@2@@boost@@@boost@@
V?$allocator@U?$list_edge@IU?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@boost@@@std@@@std@
00420568  add         esp,0Ch
0042056B  mov         ecx,eax
0042056D  call        @ILT+2355(??$?4U?$out_edge_iter@Viterator@?$vector@
V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@
IU?$property@W4edge_weight_t@boost@@IUno_property@2
@@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@detail@boost@@V?$allocator@V
?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@
IU?$property@W4edge_weight_t@boost@@IUno_property@2
@@boost@@@boost@@@std@@@std@@U?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@detail@boost@@@std@@@std@@
IV?$edge_desc_impl@Ubidirectional_tag@boost@@I@detail@boost@@H@detail
@boost@@U012@@?$tuple@AAU?$out_edge_iter@Viterator@?$vector@
V?$sei_@IViterator@?$list@U?$list_edge@IU?$property@W4edge_weight_t@boost@@
IUno_property@2@@boost@@@boost@@V?$allocator@U?$list_edge@
IU?$property@W4edge_weight_t@boost@@IUno_property@2
@@boost@@@boost@@@std@@@std@@U?$property@W4edge_w
00420572  mov         ecx,dword ptr [ee]
00420575  mov         dword ptr [eMax],ecx
00420578  mov         edx,dword ptr [ebp-24h]
0042057B  mov         dword ptr [ebp-34h],edx
0042057E  jmp         foo+0B8h (420588h)
00420580  lea         ecx,[ei]
00420583  call
boost::iterator_facade<boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> > > >::iterator,unsigned
int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,int>,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,boost::random_access_traversal_tag,bo
00420588  lea         eax,[ee]
0042058B  push        eax
0042058C  lea         ecx,[ei]
0042058F  push        ecx
00420590  call
boost::operator!=<boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> > > >::iterator,unsigned
int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,int>,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,boost::random_access_traversal_tag,boost::
00420595  add         esp,8
00420598  movzx       edx,al
0042059B  test        edx,edx
0042059D  je          foo+114h (4205E4h)
    {
        nChk = wgt[*ei];
0042059F  lea         eax,[ebp-180h]
004205A5  push        eax
004205A6  lea         ecx,[ei]
004205A9  call
boost::iterator_facade<boost::detail::out_edge_iter<std::vector<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> >,std::allocator<boost::detail::sei_<unsigned
int,std::list<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>
,std::allocator<boost::list_edge<unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property> > >
::iterator,boost::property<enum boost::edge_weight_t,unsigned
int,boost::no_property> > > >::iterator,unsigned
int,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,int>,boost::detail::edge_desc_impl<boost::bidirectional_tag,unsigned
int>,boost::random_access_traversal_tag,bo
004205AE  sub         esp,0Ch
004205B1  mov         ecx,esp
004205B3  mov         edx,dword ptr [eax]
004205B5  mov         dword ptr [ecx],edx
004205B7  mov         edx,dword ptr [eax+4]
004205BA  mov         dword ptr [ecx+4],edx
004205BD  mov         eax,dword ptr [eax+8]
004205C0  mov         dword ptr [ecx+8],eax
004205C3  lea         ecx,[wgt]
004205C6  call
boost::adj_list_edge_property_map<boost::bidirectional_tag,unsigned
int,unsigned int &,unsigned int,boost::property<enum
boost::edge_weight_t,unsigned int,boost::no_property>,enum
boost::edge_weight_t>::operator[] (41E2E3h)
;;LOOK MA! NO 'cmp' INSTRUCTION! WHERE'D IT GO?!!?
004205CB  mov         ecx,dword ptr [eax]
004205CD  mov         dword ptr [nChk],ecx
        if(nChk > nTopWgt);
        {
            nTopWgt = nChk;
004205D0  mov         eax,dword ptr [nChk]
004205D3  mov         dword ptr [nTopWgt],eax
            eMax = ei;
004205D6  mov         eax,dword ptr [ei]
004205D9  mov         dword ptr [eMax],eax
004205DC  mov         ecx,dword ptr [ebp-14h]
004205DF  mov         dword ptr [ebp-34h],ecx
        }
    }

I repeat that this is not a boost issue per se but this bug might show up
more often when compiling all those templates ...

Eric

[Boost-users] Bizarre behaviour with Microsoft compiler

Eric Fowler