Hi,
On 02/03/2015 03:19 PM, Jason Merrill wrote:
On 02/03/2015 05:45 AM, Paolo Carlini wrote:
+ if (TREE_CODE (pfn0) != ADDR_EXPR
+ || !decl_with_nonnull_addr_p (TREE_OPERAND (pfn0, 0)))
I don't like duplicating the logic for when we might know the pfn is
non-null; that seems fragile.
I agree, seems fragile, on the other hand would be rather precise, IMHO.
We could at least have a function wrapping the above and a comment in
both places. Anyway...
I'd rather go with the tf_none approach, or otherwise suppress the
warning.
There are so many ways to fix this, and I'm a bit confused by the range
of warning suppression mechanisms we have got at this point (eg,
TREE_NO_WARNING, c_inhibit_evaluation_warnings, the new warning_sentinel
in pt.c, tf_none, etc.. ;) But this case should be at least relatively
safe because the expression is internally generated, right? Fiddling
with tf_none, as mentioned by Manuel, should indeed work, but then, how
far we would go with that? Only the 'e2 = cp_build_binary_op (location,
EQ_EXPR, pfn0, ...)' lines or more of the calls for synthesized
expressions? Would it be Ok for 5.0 to just use TREE_NO_WARNING like in
the below?
Thanks,
Paolo.
/////////////////////
Index: cp/typeck.c
===================================================================
--- cp/typeck.c (revision 220371)
+++ cp/typeck.c (working copy)
@@ -4415,7 +4415,8 @@ cp_build_binary_op (location_t location,
&& decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
{
if ((complain & tf_warning)
- && c_inhibit_evaluation_warnings == 0)
+ && c_inhibit_evaluation_warnings == 0
+ && !TREE_NO_WARNING (op0))
warning (OPT_Waddress, "the address of %qD will never be NULL",
TREE_OPERAND (op0, 0));
}
@@ -4436,7 +4437,8 @@ cp_build_binary_op (location_t location,
&& decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
{
if ((complain & tf_warning)
- && c_inhibit_evaluation_warnings == 0)
+ && c_inhibit_evaluation_warnings == 0
+ && !TREE_NO_WARNING (op1))
warning (OPT_Waddress, "the address of %qD will never be NULL",
TREE_OPERAND (op1, 0));
}
@@ -4537,6 +4539,8 @@ cp_build_binary_op (location_t location,
op1 = save_expr (op1);
pfn0 = pfn_from_ptrmemfunc (op0);
+ /* Avoid -Waddress warnings (c++/64877). */
+ TREE_NO_WARNING (pfn0) = 1;
pfn1 = pfn_from_ptrmemfunc (op1);
delta0 = delta_from_ptrmemfunc (op0);
delta1 = delta_from_ptrmemfunc (op1);
Index: testsuite/g++.dg/warn/Waddress-2.C
===================================================================
--- testsuite/g++.dg/warn/Waddress-2.C (revision 0)
+++ testsuite/g++.dg/warn/Waddress-2.C (working copy)
@@ -0,0 +1,24 @@
+// PR c++/64877
+// { dg-options "-Waddress" }
+
+template<class Derived>
+struct S
+{
+ void m() {
+ }
+
+ S()
+ {
+ if (&S<Derived>::Unwrap != &Derived::Unwrap)
+ m();
+ }
+
+ void Unwrap() {
+ }
+};
+
+struct T : public S<T>
+{
+};
+
+T t;
