https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85398
--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
A simpler test case is this (which is analogous to what the loop is transformed
into):
$ cat x.c && gcc -O2 -S -Wall x.c
unsigned left[1];
unsigned long right[1];
void f (unsigned i)
{
if (i)
left[i] = right[i - 1];
}
x.c: In function ‘f’:
x.c:7:11: warning: array subscript [0, 0] is outside array bounds of ‘unsigned
int[1]’ [-Warray-bounds]
left[i] = right[i - 1];
~~~~^~~
Here it's even more obvious that the warning is wrong.
It seems to me that the whole if statement could either be eliminated or its
body replaced by a trap because the assignment in it is undefined. That would
eliminate the loop (and with it also the warning).
