https://gcc.gnu.org/g:c5c3a4a265256535a66f1656d44e143f05d77f66
commit r12-10439-gc5c3a4a265256535a66f1656d44e143f05d77f66
Author: Andrew MacLeod <amacl...@redhat.com>
Date: Fri May 10 13:56:01 2024 -0400
Fix range-ops operator_addr.
Lack of symbolic information prevents op1_range from being able to draw
the same conclusions as fold_range can.
PR tree-optimization/111009
gcc/
* range-op.cc (operator_addr_expr::op1_range): Be more restrictive.
* value-range.h (contains_zero_p): New.
gcc/testsuite/
* gcc.dg/pr111009.c: New.
Diff:
---
gcc/range-op.cc | 12 +++++++++++-
gcc/testsuite/gcc.dg/pr111009.c | 38 ++++++++++++++++++++++++++++++++++++++
gcc/value-range.h | 10 ++++++++++
3 files changed, 59 insertions(+), 1 deletion(-)
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index bf95f5fbaa1c..2e0d67b70b65 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -3825,7 +3825,17 @@ operator_addr_expr::op1_range (irange &r, tree type,
const irange &op2,
relation_kind rel ATTRIBUTE_UNUSED) const
{
- return operator_addr_expr::fold_range (r, type, lhs, op2);
+ if (empty_range_varying (r, type, lhs, op2))
+ return true;
+
+ // Return a non-null pointer of the LHS type (passed in op2), but only
+ // if we cant overflow, eitherwise a no-zero offset could wrap to zero.
+ // See PR 111009.
+ if (!contains_zero_p (lhs) && TYPE_OVERFLOW_UNDEFINED (type))
+ r = range_nonzero (type);
+ else
+ r.set_varying (type);
+ return true;
}
diff --git a/gcc/testsuite/gcc.dg/pr111009.c b/gcc/testsuite/gcc.dg/pr111009.c
new file mode 100644
index 000000000000..3accd9ac0630
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr111009.c
@@ -0,0 +1,38 @@
+/* PR tree-optimization/111009 */
+/* { dg-do run } */
+/* { dg-options "-O3 -fno-strict-overflow" } */
+
+struct dso {
+ struct dso * next;
+ int maj;
+};
+
+__attribute__((noipa)) static void __dso_id__cmp_(void) {}
+
+__attribute__((noipa))
+static int bug(struct dso * d, struct dso *dso)
+{
+ struct dso **p = &d;
+ struct dso *curr = 0;
+
+ while (*p) {
+ curr = *p;
+ // prevent null deref below
+ if (!dso) return 1;
+ if (dso == curr) return 1;
+
+ int *a = &dso->maj;
+ // null deref
+ if (!(a && *a)) __dso_id__cmp_();
+
+ p = &curr->next;
+ }
+ return 0;
+}
+
+__attribute__((noipa))
+int main(void) {
+ struct dso d = { 0, 0, };
+ bug(&d, 0);
+}
+
diff --git a/gcc/value-range.h b/gcc/value-range.h
index d4cba22d540f..22f5fc68d7cb 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -605,6 +605,16 @@ irange::normalize_kind ()
}
}
+inline bool
+contains_zero_p (const irange &r)
+{
+ if (r.undefined_p ())
+ return false;
+
+ tree zero = build_zero_cst (r.type ());
+ return r.contains_p (zero);
+}
+
// Return the maximum value for TYPE.
inline tree
