https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86691
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=86613,
| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=86611
Blocks| |56456
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
See also pr86613 and pr86611 for other examples of missing -Warray-bounds due
to early folding of out-of-bounds accesses by different passes. It's possible
that they all could be due to the same underlying bug. The one here is the
result of the folding in fold_array_ctor_reference() in gimple-fold.c. The
function ends with the following:
/* Memory not explicitly mentioned in constructor is 0 (or
the reference is out of range). */
return type ? build_zero_cst (type) : NULL_TREE;
}
However, negative indices are not folded as a result of the following code in
fold_const_aggregate_ref_1(), also in gimple-fold.c:
/* Out of bound array access. Value is undefined, but don't fold. */
if (maybe_lt (offset, 0))
return NULL_TREE;
So it seems that fold_array_ctor_reference() needs to also avoid folding
out-of-bounds array references.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56456
[Bug 56456] [meta-bug] bogus/missing -Warray-bounds
