[Bug gcov-profile/101554] New: [GCOV] The coverage of "for" goes wrong.

[njuwy at smail dot nju.edu.cn via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101554

            Bug ID: 101554
           Summary: [GCOV] The coverage of "for" goes wrong.
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: njuwy at smail dot nju.edu.cn
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-pc-linux-gnu/10.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure -enable-checking=release -enable-languages=c,c++
-disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 10.2.0 (GCC) 


$ cat test.c
#include<stdlib.h>
int a[251];
int __attribute__((noinline)) t(int i) {
  if (i == 0)
    exit(0);
  if (i > 255)
    abort();
}
int main() {
  unsigned int i;
  for (i = 0;; i++) {
    a[i] = t((unsigned char)(i + 5));
  }
}


$ gcc -O0 --coverage test.c;./a.out;gcov test;cat test.c.gcov
libgcov profiling error:/home/wangyang/coverage/test/test.gcda:overwriting an
existing profile data with a different timestamp
File 'test.c'
Lines executed:88.89% of 9
Creating 'test.c.gcov'

        -:    0:Source:test.c
        -:    0:Graph:test.gcno
        -:    0:Data:test.gcda
        -:    0:Runs:1
        -:    1:#include<stdlib.h>
        -:    2:int a[251];
      252:    3:int __attribute__((noinline)) t(int i) {
      252:    4:  if (i == 0)
        1:    5:    exit(0);
      251:    6:  if (i > 255)
    #####:    7:    abort();
      251:    8:}
        1:    9:int main() {
        -:   10:  unsigned int i;
        1:   11:  for (i = 0;; i++) {
      252:   12:    a[i] = t((unsigned char)(i + 5));
        -:   13:  }
        -:   14:}

Line 11 was executed 252 times