https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97336
--- Comment #2 from Christian Franke <franke at computer dot org> ---
Sorry, but I disagree that this report is INVALID.
Unlike for example -Wstringop-overflow, warnings like -Wstring-compare should
IMO only occur if the warning condition holds for *all* function calls
generated by loop unrolling.
BTW, if the partial loop unrolling is done manually, the warning should occur,
but does not:
int f(const char * p, int n)
{
char buf[10] = {0, };
int i = 0;
if (n <= 0) {
if (!__builtin_strncmp(buf, "12345", 5) // <== no warning
&& (i == 5 || buf[5] == ' ')) // <== warning if removed
return 1;
}
else {
do {
buf[i] = p[i]; i++;
} while (i < (int)sizeof(buf)-1 && i < n);
if (!__builtin_strncmp(buf, "12345", 5)
&& (i == 5 || buf[5] == ' '))
return 1;
}
return 0;
}
With the above code, the warning occurs if the condition "&& (i == 5 || buf[5]
== ' ')" is removed. If this is done in the original testcase, the warning does
no longer occur.
