https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95673
Franz Sirl <sirl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |sirl at gcc dot gnu.org
--- Comment #5 from Franz Sirl <sirl at gcc dot gnu.org> ---
Wstring-compare seems to depend a lot on the optimizations. In the following
testcase warnings are also inconsistent and fragile (slight changes make the
warning disappear):
int c, d, e;
void f(void) {
const char *file = (c & 7) ? "file1234.txt" : "x";
const char *file2 = (c & 7) ? "y" : "file12.txt";
if (c == 2)
if (d
|| __builtin_strcmp(file, "file123.txt")
|| __builtin_strcmp(file2, "file123.txt")
)
e = 2;
}
With "gcc -c -O2 -Wstring-compare testcase.c" current trunk shows:
testcase.c: In function 'f':
testcase.c:8:12: warning: '__builtin_strcmp' of a string of length 11 and an
array of size 11 evaluates to nonzero [-Wstring-compare]
8 | || __builtin_strcmp(file2, "file123.txt")
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There is no warning for line 7 ('file').
Maybe the warning could also be a bit more verbose when the information is
available, like for example:
warning: '__builtin_strcmp' of a string ('file2' with content "y" ||
"file12.txt") and an array ("file123.txt") of size 11 always evaluates to
nonzero [-Wstring-compare]
