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| author | Martin Sebor <msebor@redhat.com> | 2021-07-28 16:25:40 -0600 |
|---|---|---|
| committer | Martin Sebor <msebor@redhat.com> | 2021-07-28 16:25:40 -0600 |
| commit | 1121e495b70105deeb82295f8210e30f2080bc37 (patch) | |
| tree | 2848e49b3eef7021e3e034f6a7f31f68a946350d /gcc/tree-ssa-uninit.c | |
| parent | b9cbf8c9e0bc72f59b643165247fae646560aadd (diff) | |
| download | gcc-1121e495b70105deeb82295f8210e30f2080bc37.zip gcc-1121e495b70105deeb82295f8210e30f2080bc37.tar.gz gcc-1121e495b70105deeb82295f8210e30f2080bc37.tar.bz2 | |
Correct uninitialized object offset and size computation [PR101494].
Resolves:
PR middle-end/101494 - -Wuninitialized false alarm with memrchr of size 0
gcc/ChangeLog:
PR middle-end/101494
* tree-ssa-uninit.c (maybe_warn_operand): Correct object offset
and size computation.
gcc/testsuite/ChangeLog:
PR middle-end/101494
* gcc.dg/uninit-pr101494.c: New test.
Diffstat (limited to 'gcc/tree-ssa-uninit.c')
| -rw-r--r-- | gcc/tree-ssa-uninit.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/gcc/tree-ssa-uninit.c b/gcc/tree-ssa-uninit.c index ab64a68..5d7bc80 100644 --- a/gcc/tree-ssa-uninit.c +++ b/gcc/tree-ssa-uninit.c @@ -371,16 +371,20 @@ maybe_warn_operand (ao_ref &ref, gimple *stmt, tree lhs, tree rhs, || get_no_uninit_warning (base)) return NULL_TREE; - /* Do not warn if the access is fully outside of the variable. */ + /* Do not warn if the access is zero size or if it's fully outside + the object. */ poly_int64 decl_size; + if (known_size_p (ref.size) + && known_eq (ref.max_size, ref.size) + && (known_eq (ref.size, 0) + || known_le (ref.offset + ref.size, 0))) + return NULL_TREE; + if (DECL_P (base) - && ((known_size_p (ref.size) - && known_eq (ref.max_size, ref.size) - && known_le (ref.offset + ref.size, 0)) - || (known_ge (ref.offset, 0) - && DECL_SIZE (base) - && poly_int_tree_p (DECL_SIZE (base), &decl_size) - && known_le (decl_size, ref.offset)))) + && known_ge (ref.offset, 0) + && DECL_SIZE (base) + && poly_int_tree_p (DECL_SIZE (base), &decl_size) + && known_le (decl_size, ref.offset)) return NULL_TREE; /* Do not warn if the result of the access is then used for |