https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116279
Bug ID: 116279
Summary: Branch coverage measure is reported in inconsistent
ways for comma operators
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: gcov-profile
Assignee: unassigned at gcc dot gnu.org
Reporter: wentaoz5 at illinois dot edu
Target Milestone: ---
How to reproduce:
$ gcc --version
gcc (GCC) 15.0.0 20240723 (experimental)
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ cat << EOF > test.c
int x, y;
int main(int argc, char **argv) {
if (
x
,
y
)
return 0;
return 0;
}
EOF
$ gcc --coverage test.c -o test
$ ./test
$ gcov -b -c test
$ cat test.c.gcov
-: 0:Source:test.c
-: 0:Graph:test.gcno
-: 0:Data:test.gcda
-: 0:Runs:1
-: 1:int x, y;
-: 2:
function main called 1 returned 100% blocks executed 75%
1: 3:int main(int argc, char **argv) {
1: 4: if (
1: 5: x
branch 0 taken 0 (fallthrough)
branch 1 taken 1
-: 6: ,
-: 7: y
-: 8: )
#####: 9: return 0;
1: 10: return 0;
-: 11:}
With the same language construct, but this time we introduce some side effects,
branch coverage measure would be associated to different lines.
Variant 1:
-: 0:Source:test.c
-: 0:Graph:test.gcno
-: 0:Data:test.gcda
-: 0:Runs:1
-: 1:int x, y;
-: 2:
function main called 1 returned 100% blocks executed 75%
1: 3:int main(int argc, char **argv) {
1: 4: if (
-: 5: x
1: 6: ,
branch 0 taken 0 (fallthrough)
branch 1 taken 1
-: 7: y++
-: 8: )
#####: 9: return 0;
1: 10: return 0;
-: 11:}
Variant 2:
-: 0:Source:test.c
-: 0:Graph:test.gcno
-: 0:Data:test.gcda
-: 0:Runs:1
-: 1:int x, y;
-: 2:
function main called 1 returned 100% blocks executed 75%
1: 3:int main(int argc, char **argv) {
1: 4: if (
1: 5: x++
-: 6: ,
1: 7: y++
branch 0 taken 0 (fallthrough)
branch 1 taken 1
-: 8: )
#####: 9: return 0;
1: 10: return 0;
-: 11:}
