[Bug gcov-profile/101342] New: [Gcov] Wrong coverage with "for(;;a++)" loop statement

[byone.heng at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101342

            Bug ID: 101342
           Summary: [Gcov] Wrong coverage with "for(;;a++)"  loop
                    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
volatile long int true_var = 1;
const long int false_var = 0;
int a=0;
int main() {
  for (;; a++) {
    int c[1];
    if( true_var > 0 )
    {
    if (a) {
      break;
      a;
      continue; /* count(1) */
    }
    continue;
    } /* count(1) */
  }
  return 0;
}

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

-:    1:/* { dg-options "-fprofile-arcs -ftest-coverage" } */
-:    2:/* { dg-do run { target native } } */
-:    3:
-:    4:volatile long int true_var = 1;
-:    5:const long int false_var = 0;
-:    6:
-:    7:int a=0;
-:    8:
2:    9:int main() {
1:   10:  for (;; a++) {
-:   11:    int c[1];
2:   12:    if( true_var > 0 )
-:   13:    {
2:   14:    if (a) {
1:   15:      break;
-:   16:      a;
1:   17:      continue; /* count(1) */
-:   18:    }
1:   19:    continue;
-:   20:    } /* count(1) */
-:   21:  }
-:   22:
1:   23:  return 0;
-:   24:}
-:   25:
-:   26:/* { dg-final { run-gcov gcov-pr85217.c } } */

Line 10 is wrongly marked as executed once which should be executed twice.