https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80776
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2017-05-16 00:00:00 |2020-3-4
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=94021
Known to fail|6.3.0, 7.1.0 |10.0, 6.4.0, 7.5.0, 8.4.0,
| |9.2.0
--- Comment #7 from Martin Sebor <msebor at gcc dot gnu.org> ---
Reconfirming that test case in comment #2 still triggers the warning in GCC 10.
The dump shows that the warning thinks the fifth directive (%02d) generates
between 2 and 10 bytes of output. The symptoms feel similar to pr94021 but I
haven't looked into whether they underlying root causes are related.
Result: 2, 10, 10, 10 (12, 20, 20, 20)
$ gcc -O2 -S -Wall -fdump-tree-strlen=/dev/stdout pr80776-c2.c
;; Function f (f, funcdef_no=0, decl_uid=1936, cgraph_uid=1, symbol_order=1)
;; 1 loops found
;;
;; Loop 0
;; header 0, latch 1
;; depth 0, outer -1
;; nodes: 0 1 2
;; 2 succs { 1 }
pr80776-c2.c:14: __builtin_sprintf: objsize = 15, fmtstr =
"%04d%02d%02d%02d%02d%02d"
Directive 1 at offset 0: "%04d"
Result: 4, 4, 4, 4 (4, 4, 4, 4)
Directive 2 at offset 4: "%02d"
Result: 2, 2, 2, 2 (6, 6, 6, 6)
Directive 3 at offset 8: "%02d"
Result: 2, 2, 2, 2 (8, 8, 8, 8)
Directive 4 at offset 12: "%02d"
Result: 2, 2, 2, 2 (10, 10, 10, 10)
Directive 5 at offset 16: "%02d"
pr80776-c2.c: In function ‘f’:
pr80776-c2.c:14:44: warning: ‘%02d’ directive writing between 2 and 10 bytes
into a region of size 5 [-Wformat-overflow=]
14 | __builtin_sprintf (buf, "%04d%02d%02d%02d%02d%02d", a, b, c, d, e,
f);
| ^~~~
pr80776-c2.c:14:27: note: directive argument in the range [0, 2147483647]
14 | __builtin_sprintf (buf, "%04d%02d%02d%02d%02d%02d", a, b, c, d, e,
f);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
Result: 2, 10, 10, 10 (12, 20, 20, 20)
Directive 6 at offset 20: "%02d"
pr80776-c2.c:14:27: note: directive argument in the range [0, 60]
Result: 2, 2, 2, 2 (14, 22, 22, 22)
Directive 7 at offset 24: "", length = 1
pr80776-c2.c:14:3: note: ‘__builtin_sprintf’ output between 15 and 23 bytes
into a destination of size 15
14 | __builtin_sprintf (buf, "%04d%02d%02d%02d%02d%02d", a, b, c, d, e,
f);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
f (int a, int b, int c, int d, int e, int f)
{
<bb 2> [local count: 1073741824]:
__builtin_sprintf (&buf, "%04d%02d%02d%02d%02d%02d", a_14(D), b_15(D),
c_16(D), d_17(D), e_18(D), f_19(D));
return;
}
