[Bug gcov-profile/83266] [GCOV] A True if statement is wrongly marked as not executed in gcov

[yangyibiao at nju dot edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83266

--- Comment #1 from Yibiao Yang <yangyibiao at nju dot edu.cn> ---
I am not very sure whether this is a bug or it is only the default behavior in
gcov. 

(In reply to Yibiao Yang from comment #0)
> $ gcc -v
> Using built-in specs.
> COLLECT_GCC=gcc
> COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
> OFFLOAD_TARGET_NAMES=nvptx-none
> OFFLOAD_TARGET_DEFAULT=1
> Target: x86_64-linux-gnu
> Configured with: ../src/configure -v --with-pkgversion='Ubuntu
> 7.2.0-8ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs
> --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
> --with-gcc-major-version-only --program-suffix=-7
> --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
> --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
> --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
> --enable-libstdcxx-debug --enable-libstdcxx-time=yes
> --with-default-libstdcxx-abi=new --enable-gnu-unique-object
> --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
> --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto
> --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64
> --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
> --enable-offload-targets=nvptx-none --without-cuda-driver
> --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
> --target=x86_64-linux-gnu
> Thread model: posix
> gcc version 7.2.0 (Ubuntu 7.2.0-8ubuntu3) 
> 
> $ cat small.c
> int main()
> {
>     int i = 1;
>     if (i > 0) {
>         i++;
>     }
> 
>     if (1 > 0)  {
>         i++;
>     }
> }
> 
> $ gcc -fprofile-arcs -ftes-coverage small.c; ./a.out; gcov small.c; cat
> small.c.gcov
> File 'small.c'
> Lines executed:100.00% of 5
> Creating 'small.c.gcov'
> 
> File '<built-in>'
> No executable lines
> Removing '<built-in>.gcov'
> 
>         -:    0:Source:small.c
>         -:    0:Graph:small.gcno
>         -:    0:Data:small.gcda
>         -:    0:Runs:1
>         -:    0:Programs:1
>         1:    1:int main()
>         -:    2:{
>         1:    3:    int i = 1;
>         1:    4:    if (i > 0) {
>         1:    5:        i++;
>         -:    6:    }
>         -:    7:
>         -:    8:    if (1 > 0)  {
>         1:    9:        i++;
>         -:   10:    }
>         -:   11:}
> 
> As we can find that Line #4 is marked as executed and Line #8 is marked as
> not executed.