[Bug c++/44599] New: very basic recurring template only works when using g++ -O option

[gcc at razorcam dot com]

the following program with a very basic recurring template compiles with no
message but only return the expected value zero when using g++ -O optimize
option
the output of g++ -v -save-temps follows the source file bug_report.cpp
the preprocessed file bug_report.ii is at the end of this report

template<class C> struct Interface{
        int getI(){return ((C*)this)->_getI();} 
};

struct S:Interface<S>{
        int i;
        int _getI(){return i;}
};

template<class C> int f(Interface<C> obj){return obj.getI();}

int main(){
        S s; s.i=0;
        return f(s);
}


g++ -v -save-temps bug_report.cpp && ./a.out && echo $?
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.4.4-3'
--with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--enable-multiarch --enable-linker-build-id --with-system-zlib
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls
--enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc
--with-arch-32=i486 --with-tune=generic --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.4.4 (Debian 4.4.4-3) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-shared-libgcc' '-mtune=generic'
 /usr/lib/gcc/x86_64-linux-gnu/4.4.4/cc1plus -E -quiet -v -D_GNU_SOURCE
bug_report.cpp -mtune=generic -fpch-preprocess -o bug_report.ii
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../../../x86_64-linux-gnu/include"
ignoring nonexistent directory "/usr/include/x86_64-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/c++/4.4
 /usr/include/c++/4.4/x86_64-linux-gnu
 /usr/include/c++/4.4/x86_64-linux-gnu
 /usr/include/c++/4.4/backward
 /usr/local/include
 /usr/lib/gcc/x86_64-linux-gnu/4.4.4/include
 /usr/lib/gcc/x86_64-linux-gnu/4.4.4/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-shared-libgcc' '-mtune=generic'
 /usr/lib/gcc/x86_64-linux-gnu/4.4.4/cc1plus -fpreprocessed bug_report.ii
-quiet -dumpbase bug_report.cpp -mtune=generic -auxbase bug_report -version -o
bug_report.s
GNU C++ (Debian 4.4.4-3) version 4.4.4 (x86_64-linux-gnu)
        compiled by GNU C version 4.4.4, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=57 --param ggc-min-heapsize=51739
GNU C++ (Debian 4.4.4-3) version 4.4.4 (x86_64-linux-gnu)
        compiled by GNU C version 4.4.4, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=57 --param ggc-min-heapsize=51739
Compiler executable checksum: a92c574e76687c18572fdbea97434cec
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-shared-libgcc' '-mtune=generic'
 as --traditional-format -V -Qy -o bug_report.o bug_report.s
GNU assembler version 2.20.1 (x86_64-linux-gnu) using BFD version (GNU Binutils
for Debian) 2.20.1-system.20100303
COMPILER_PATH=/usr/lib/gcc/x86_64-linux-gnu/4.4.4/:/usr/lib/gcc/x86_64-linux-gnu/4.4.4/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/4.4.4/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/4.4.4/:/usr/lib/gcc/x86_64-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/x86_64-linux-gnu/4.4.4/:/usr/lib/gcc/x86_64-linux-gnu/4.4.4/:/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-shared-libgcc' '-mtune=generic'
 /usr/lib/gcc/x86_64-linux-gnu/4.4.4/collect2 --build-id --eh-frame-hdr -m
elf_x86_64 --hash-style=both -dynamic-linker /lib64/ld-linux-x86-64.so.2
/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../../../lib/crt1.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../../../lib/crti.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.4/crtbegin.o
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.4 -L/usr/lib/gcc/x86_64-linux-gnu/4.4.4
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../../../lib -L/lib/../lib
-L/usr/lib/../lib -L/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../.. bug_report.o
-lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc
/usr/lib/gcc/x86_64-linux-gnu/4.4.4/crtend.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.4/../../../../lib/crtn.o


 cat bug_report.ii
# 1 "bug_report.cpp"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "bug_report.cpp"
template<class C> struct Interface{
 int getI(){return ((C*)this)->_getI();}
};

struct S:Interface<S>{
 int i;
 int _getI(){return i;}
};

template<class C> int f(Interface<C> obj){return obj.getI();}

int main(){
 S s; s.i=0;
 return f(s);
}


-- 
           Summary: very basic recurring template only works when using g++
                    -O option
           Product: gcc
           Version: 4.4.4
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gcc at razorcam dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44599