[Bug gcov-profile/101413] New: [Gcov] wrong coverage for a return statement

[byone.heng at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101413

            Bug ID: 101413
           Summary: [Gcov] wrong coverage for a return statement
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: byone.heng at gmail dot com
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

$./gcc -v                                                                       
Using built-in specs.
COLLECT_GCC=./gcc
COLLECT_LTO_WRAPPER=/home/x/project/gcc/build/install/libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --prefix=/home/x/project/gcc/build/install
--enable-checking=release --enable-languages=c,c++ --disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20210105 (experimental) (GCC)

$cat test.c
——————————————————————————

const volatile short int true_var = 1;
volatile int false_var = 0;

#include <time.h>
static int weak_gettime (clockid_t clk_id, struct timespec *tp)
  __attribute__((__weakref__("clock_gettime")));
int main() {
  if (!clock_gettime)
    return 0;
  struct timespec ts;
  if( true_var > 0 )
  {
  return weak_gettime(CLOCK_MONOTONIC, &ts);
  }
}

——————————————————————————


$gcc -O0 --coverage test.c;./a.out;gcov test;cat test.c.gcov

       -:    1:/* { dg-do run { target { *-*-linux* *-*-freebsd* } } } */
        -:    2:
        -:    3:const volatile short int true_var = 1;
        -:    4:volatile int false_var = 0;
        -:    5:
        -:    6:#include <time.h>
        -:    7:static int weak_gettime (clockid_t clk_id, struct timespec *tp)
        -:    8:  __attribute__((__weakref__("clock_gettime")));
        1:    9:int main() {
        -:   10:  if (!clock_gettime)
        1:   11:    return 0;
        -:   12:  struct timespec ts;
        1:   13:  if( true_var > 0 )
        -:   14:  {
        1:   15:  return weak_gettime(CLOCK_MONOTONIC, &ts);
        -:   16:  }
        -:   17:}


Line 11 should not be executed.