[Bug gcov-profile/90066] New: [GCOV] function with inline attribute leading to incorrect coverage for the "if" statement

[yangyibiao at nju dot edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90066

            Bug ID: 90066
           Summary: [GCOV] function with inline attribute leading to
                    incorrect coverage for the "if" statement
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: yangyibiao at nju dot edu.cn
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
8.2.0-1ubuntu2~18.04' --with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--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 8.2.0 (Ubuntu 8.2.0-1ubuntu2~18.04)


$ cat small.c
int check_int (int *i, int align)
{
  *i = 20;
  return *i;
}

typedef int aligned __attribute__((aligned(64)));

static void
inline __attribute__((always_inline))
foo (void)
{
  aligned i;
  if (check_int (&i, __alignof__(i)) != i)
    ; // abort ();
}

int main()
{
  foo ();
  return 0;
}


$ gcc -w -O0 --coverage small.c; ./a.out; gcov-8 small.c; cat small.c.gcov
File 'small.c'
Lines executed:100.00% of 6
Creating 'small.c.gcov'

        -:    0:Source:small.c
        -:    0:Graph:small.gcno
        -:    0:Data:small.gcda
        -:    0:Runs:1
        -:    0:Programs:1
        1:    1:int check_int (int *i, int align)
        -:    2:{
        1:    3:  *i = 20;
        1:    4:  return *i;
        -:    5:}
        -:    6:
        -:    7:typedef int aligned __attribute__((aligned(64)));
        -:    8:
        -:    9:static void
        -:   10:inline __attribute__((always_inline))
        -:   11:foo (void)
        -:   12:{
        -:   13:  aligned i;
        2:   14:  if (check_int (&i, __alignof__(i)) != i)
        -:   15:    ; // abort ();
        -:   16:}
        -:   17:
        1:   18:int main()
        -:   19:{
        -:   20:  foo ();
        1:   21:  return 0;
        -:   22:}


Line #14 is wrongly marked as executed twice. This statement should be only
executed once. 



1. While Line #10 @@inline __attribute__((always_inline))@@ is removed, the
result is correct as:
$ gcc -w -O0 --coverage small.c; ./a.out; gcov-8 small.c; cat small.c.gcov
File 'small.c'
Lines executed:100.00% of 9
Creating 'small.c.gcov'

        -:    0:Source:small.c
        -:    0:Graph:small.gcno
        -:    0:Data:small.gcda
        -:    0:Runs:1
        -:    0:Programs:1
        1:    1:int check_int (int *i, int align)
        -:    2:{
        1:    3:  *i = 20;
        1:    4:  return *i;
        -:    5:}
        -:    6:
        -:    7:typedef int aligned __attribute__((aligned(64)));
        -:    8:
        -:    9:static void
        -:   10:// inline __attribute__((always_inline))
        1:   11:foo (void)
        -:   12:{
        -:   13:  aligned i;
        1:   14:  if (check_int (&i, __alignof__(i)) != i)
        -:   15:    ; // abort ();
        1:   16:}
        -:   17:
        1:   18:int main()
        -:   19:{
        1:   20:  foo ();
        1:   21:  return 0;
        -:   22:}

2. While Line #12 is not removed, the result is also correct as: 
$ gcc -w -O0 --coverage small.c; ./a.out; gcov-8 small.c; cat small.c.gcov
File 'small.c'
Lines executed:85.71% of 7
Creating 'small.c.gcov'

        -:    0:Source:small.c
        -:    0:Graph:small.gcno
        -:    0:Data:small.gcda
        -:    0:Runs:1
        -:    0:Programs:1
        1:    1:int check_int (int *i, int align)
        -:    2:{
        1:    3:  *i = 20;
        1:    4:  return *i;
        -:    5:}
        -:    6:
        -:    7:typedef int aligned __attribute__((aligned(64)));
        -:    8:
        -:    9:static void
        -:   10:inline __attribute__((always_inline))
        -:   11:foo (void)
        -:   12:{
        -:   13:  aligned i;
        1:   14:  if (check_int (&i, __alignof__(i)) != i)
    #####:   15:    abort ();
        -:   16:}
        -:   17:
        1:   18:int main()
        -:   19:{
        -:   20:  foo ();
        1:   21:  return 0;
        -:   22:}