https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101191
Bug ID: 101191
Summary: [GCOV] Wrong coverage with "for(;;)" statement
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<stdio.h>
#include<stdlib.h>
int x[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
int main() {
int niterations = 0, i;
for (;;) {
int i, mi, max;
max = 0;
for (i = 0; i < 10; i++) {
if (x[i] > max) {
max = x[i];
mi = i;
}
}
if (max == 0)
break;
x[mi] = 0;
niterations++;
if (niterations > 10)
abort();
}
exit(0);
}
$ 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:93.33% of 15
Creating 'test.c.gcov'
-: 0:Source:test.c
-: 0:Graph:test.gcno
-: 0:Data:test.gcda
-: 0:Runs:1
-: 1:#include<stdio.h>
-: 2:#include<stdlib.h>
-: 3:int x[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
-: 4:
1: 5:int main() {
1: 6: int niterations = 0, i;
-: 7:
9: 8: for (;;) {
-: 9: int i, mi, max;
10: 10: max = 0;
110: 11: for (i = 0; i < 10; i++) {
100: 12: if (x[i] > max) {
45: 13: max = x[i];
45: 14: mi = i;
-: 15: }
-: 16: }
10: 17: if (max == 0)
1: 18: break;
9: 19: x[mi] = 0;
9: 20: niterations++;
9: 21: if (niterations > 10)
#####: 22: abort();
-: 23: }
-: 24:
1: 25: exit(0);
-: 26:}
Line 8 should be executed 10 times
