https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109071
--- Comment #8 from Kees Cook <kees at outflux dot net> ---
The warning is about:
val = &sg->vals[index];
poc.c:20:20: warning: array subscript 4 is above array bounds of 'int[4]'
[-Warray-bounds=]
20 | val = &sg->vals[index];
| ~~~~~~~~^~~~~~~
which happens before the warn(). And if the check is moved out of the
"assign()" function, the warning goes away:
val = &sg->vals[index];
if (index >= MAX_ENTRIES)
warn();
assign(0, ptr, index);
assign(*val, ptr, index);
Normally -Warray-bounds doesn't warn when a value is totally unknown (i.e.
"index" here can be [-INT_MAX,INT_MAX]). Why does the warning change when the
MAX_ENTRIES test is moved inside assign()?
