https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79647
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |msebor at gcc dot gnu.org
Resolution|--- |INVALID
Assignee|unassigned at gcc dot gnu.org |msebor at gcc dot
gnu.org
--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
I can reproduce the warning. The VRP dump shows the following, indicating the
warning is correctly interpreting the range information passed to it.
_2724: [18446744071562067968, +INF]
_1184: [18446742819579101184, 18446744073709551032]
...
speed_main (int argc, char * * argv)
...
long unsigned int _2724;
long unsigned int _1184;
...
<bb 84> [0.06%]:
if (async_jobs_550 != 0)
goto <bb 567>; [25.00%]
...
<bb 567> [0.02%]:
loopargs_len.29_1198 = (unsigned int) async_jobs_550;
_1196 = loopargs_len.29_1198 * 584;
_2726 = (int) _1196;
loopargs_1193 = app_malloc (_2726, "array of loopargs");
_2724 = (long unsigned int) async_jobs_550;
_1184 = _2724 * 584;
memset (loopargs_1193, 0, _1184);
The call to memset above is introduced by jump threading from this one:
memset(loopargs, 0, loopargs_len * sizeof(loopargs_t));
for negative values of async_jobs (its type is int and its value is returned
from atoi()). I think the warning is justified (if not exactly clear(*)) and
indicative of a possible bug in the code. To avoid the warning, prevent
negative async_jobs values from reaching the memset, e.g., like so:
@@ -19021,6 +19021,13 @@
case OPT_ASYNCJOBS:
async_jobs = atoi(opt_arg());
+ if (async_jobs < 0) {
+ BIO_printf(bio_err,
+ "%s: async_jobs must be non-negative\n",
+ prog);
+ goto opterr;
+ }
+
if (!ASYNC_is_capable()) {
BIO_printf(bio_err,
"%s: async_jobs specified but async not
supported\n",
I'm resolving this report as invalid on that basis.
[*] The warning is unfortunately missing the inlining context which can make
some its instances hard to debug. A patch with a fix for that was submitted
last month but deferred until GCC 8
(https://gcc.gnu.org/ml/gcc-patches/2017-01/msg01994.html).
