On 09/09/2015 01:17 PM, Martin Sebor wrote:
On 09/09/2015 12:36 PM, Toon Moene wrote:
See:
https://gcc.gnu.org/ml/gcc-testresults/2015-09/msg00699.html
Full error message:
/home/toon/compilers/trunk/gcc/cp/search.c: In function 'int
accessible_p(tree, tree, bool)':
/home/toon/compilers/trunk/gcc/cp/search.c:1011:41: error: 'otype' may
be used uninitialized in this function [-Werror=maybe-uninitialized]
dfs_accessible_data d = { decl, otype };
^
Any ideas ?
It looks as though GCC assumes that TYPE can be null even though
it can't (if it was, TYPE_P (type) would then dereference a null
pointer). As a workaround until this is fixed, initializing OTYPE
with type instead of in the else block should get rid of the error.
Here's a small test case that reproduces the bogus warning:
cat t.c && /build/gcc-trunk/gcc/xg++ -B /build/gcc-trunk/gcc
-Wmaybe-uninitialized -O2 -c -fsanitize=undefined t.c
struct S { struct S *next; int i; };
int foo (struct S *s) {
int i;
if (s->i) {
struct S *p;
for (p = s; p; p = p->next)
i = p->i;
}
else
i = 0;
return i;
}
t.c: In function ‘int foo(S*)’:
t.c:14:12: warning: ‘i’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
return i;
More likely than not, the sanitization bits get in the way of VRP + jump
threading rotating the loop.
jeff
