Hi!
As the testcases show, delete[] this; can also introduce artificial
comparison that -Wnonnull-compare incorrectly warns on, and the
folding can also drop TREE_NO_WARNING if optimizing the operands
of the comparison.
There is another case in rtti, but I'll need to still test a fix for that,
so will post it incrementally.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2016-02-18 Jakub Jelinek <ja...@redhat.com>
PR c++/69850
* init.c (build_vec_delete_1): Set TREE_NO_WARNING on the NE_EXPR
condition.
* cp-gimplify.c (cp_fold): Propagate TREE_NO_WARNING from binary
operators if folding preserved the binop, just with different
arguments.
* g++.dg/warn/Wnonnull-compare-2.C: New test.
* g++.dg/warn/Wnonnull-compare-3.C: New test.
--- gcc/cp/init.c.jj 2016-02-17 23:26:29.000000000 +0100
+++ gcc/cp/init.c 2016-02-18 16:08:35.793958624 +0100
@@ -3678,12 +3678,15 @@ build_vec_delete_1 (tree base, tree maxi
body = integer_zero_node;
/* Outermost wrapper: If pointer is null, punt. */
+ tree cond
+ = fold_build2_loc (input_location, NE_EXPR, boolean_type_node, base,
+ fold_convert (TREE_TYPE (base), nullptr_node));
+ /* This is a compiler generated comparison, don't emit
+ e.g. -Wnonnull-compare warning for it. */
+ if (TREE_CODE (cond) == NE_EXPR)
+ TREE_NO_WARNING (cond) = 1;
body = fold_build3_loc (input_location, COND_EXPR, void_type_node,
- fold_build2_loc (input_location,
- NE_EXPR, boolean_type_node, base,
- fold_convert (TREE_TYPE (base),
- nullptr_node)),
- body, integer_zero_node);
+ cond, body, integer_zero_node);
body = build1 (NOP_EXPR, void_type_node, body);
if (controller)
--- gcc/cp/cp-gimplify.c.jj 2016-02-08 18:39:18.000000000 +0100
+++ gcc/cp/cp-gimplify.c 2016-02-18 11:20:08.491365580 +0100
@@ -2068,6 +2068,9 @@ cp_fold (tree x)
else
x = fold (x);
+ if (TREE_NO_WARNING (org_x)
+ && TREE_CODE (x) == TREE_CODE (org_x))
+ TREE_NO_WARNING (x) = 1;
break;
case VEC_COND_EXPR:
--- gcc/testsuite/g++.dg/warn/Wnonnull-compare-2.C.jj 2016-02-18
14:07:34.575846172 +0100
+++ gcc/testsuite/g++.dg/warn/Wnonnull-compare-2.C 2016-02-18
14:07:27.526942306 +0100
@@ -0,0 +1,27 @@
+// PR c++/69850
+// { dg-do compile }
+// { dg-options "-Wnonnull-compare" }
+
+struct D {
+ virtual ~D ();
+ void foo () const { delete this; } // { dg-bogus "nonnull argument" }
+ template <typename> friend struct A;
+};
+template <typename T> struct A {
+ static void bar (T *x) { x->foo (); }
+};
+template <typename T> struct B {
+ T b;
+ void baz () { A<T>::bar (&b); }
+};
+class C {
+ class E : public D { ~E (); };
+ void baz ();
+ B<E> c;
+};
+
+void
+C::baz ()
+{
+ c.baz ();
+}
--- gcc/testsuite/g++.dg/warn/Wnonnull-compare-3.C.jj 2016-02-18
16:14:32.846084103 +0100
+++ gcc/testsuite/g++.dg/warn/Wnonnull-compare-3.C 2016-02-18
16:14:43.679936198 +0100
@@ -0,0 +1,28 @@
+// PR c++/69850
+// { dg-do compile }
+// { dg-options "-Wnonnull-compare" }
+
+template <typename T>
+struct A {
+ static void foo (T *x) { x->bar (); }
+};
+template <typename T>
+struct B {
+ T b;
+ void operator= (B) { A<T>::foo (&b); }
+};
+struct C {
+ void bar () { delete[] this; } // { dg-bogus "nonnull argument" }
+};
+struct D { B<C> d; };
+struct G {
+ D g[6];
+ void baz ();
+};
+int a;
+
+void
+G::baz ()
+{
+ g[a] = g[1];
+}
Jakub
