[C++ Patch] PR 67216 ("false is still a null pointer constant")
Paolo Carlini
paolo.carlini@oracle.com
Mon Aug 17 20:14:00 GMT 2015
Hi,
On 08/17/2015 09:26 PM, Jason Merrill wrote:
> On 08/17/2015 03:20 PM, Paolo Carlini wrote:
>> On 08/17/2015 08:59 PM, Jason Merrill wrote:
>>> On 08/17/2015 02:52 PM, Paolo Carlini wrote:
>>>> On 08/17/2015 08:50 PM, Jason Merrill wrote:
>>>>> OK. I wonder if we can also drop the STRIP_NOPs on the C++11 path.
>>>> You are not alone ;) No, not trivially, without we ICE on pr51313.C.
>>>
>>> Hmm, that testcase is ill-formed. We ought to reject it, though not
>>> ICE.
>> Yes, now I see. At the moment however, I have no idea where that
>> NOP_EXPR is coming from and whether it would be safe to assume in
>> null_ptr_cst_p that one can occur only due to a bug elsewhere...
>
> I imagine it's coming from built-in folding of isdigit, which is not a
> bug.
>
>> Note
>> that integer_zerop calls STRIP_NOPS right at the beginning anyway and
>> the ICE comes from TREE_OVERFLOW.
>
> So I guess null_ptr_cst_p should check for INTEGER_CST before calling
> integer_zerop.
Yeah, and like in many other places! Thanks. Thus I'm finishing testing
the below, which handles correctly pr51313.C too. Note, I'm
intentionally leaving the old c++98 path completely alone.
Thanks,
Paolo.
-------------- next part --------------
Index: cp/call.c
===================================================================
--- cp/call.c (revision 226952)
+++ cp/call.c (working copy)
@@ -524,22 +524,34 @@ struct z_candidate {
bool
null_ptr_cst_p (tree t)
{
+ tree type = TREE_TYPE (t);
+
/* [conv.ptr]
A null pointer constant is an integral constant expression
(_expr.const_) rvalue of integer type that evaluates to zero or
an rvalue of type std::nullptr_t. */
- if (NULLPTR_TYPE_P (TREE_TYPE (t)))
+ if (NULLPTR_TYPE_P (type))
return true;
- if (CP_INTEGRAL_TYPE_P (TREE_TYPE (t)))
+
+ if (cxx_dialect >= cxx11)
{
/* Core issue 903 says only literal 0 is a null pointer constant. */
- if (cxx_dialect < cxx11)
- t = fold_non_dependent_expr (t);
+ if (TREE_CODE (type) == INTEGER_TYPE)
+ {
+ if (TREE_CODE (t) == INTEGER_CST && integer_zerop (t)
+ && !TREE_OVERFLOW (t))
+ return true;
+ }
+ }
+ else if (CP_INTEGRAL_TYPE_P (type))
+ {
+ t = fold_non_dependent_expr (t);
STRIP_NOPS (t);
if (integer_zerop (t) && !TREE_OVERFLOW (t))
return true;
}
+
return false;
}
Index: cp/pt.c
===================================================================
--- cp/pt.c (revision 226952)
+++ cp/pt.c (working copy)
@@ -22671,7 +22671,8 @@ resolve_typename_type (tree type, bool only_curren
return type;
/* If SCOPE isn't the template itself, it will not have a valid
TYPE_FIELDS list. */
- if (same_type_p (scope, CLASSTYPE_PRIMARY_TEMPLATE_TYPE (scope)))
+ if (CLASS_TYPE_P (scope)
+ && same_type_p (scope, CLASSTYPE_PRIMARY_TEMPLATE_TYPE (scope)))
/* scope is either the template itself or a compatible instantiation
like X<T>, so look up the name in the original template. */
scope = CLASSTYPE_PRIMARY_TEMPLATE_TYPE (scope);
Index: testsuite/g++.dg/cpp0x/decltype63.C
===================================================================
--- testsuite/g++.dg/cpp0x/decltype63.C (revision 0)
+++ testsuite/g++.dg/cpp0x/decltype63.C (working copy)
@@ -0,0 +1,7 @@
+// PR c++/63693
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+class C{
+ T t;
+ decltype(t)::a:: // { dg-error "expected" }
Index: testsuite/g++.dg/cpp0x/nullptr34.C
===================================================================
--- testsuite/g++.dg/cpp0x/nullptr34.C (revision 0)
+++ testsuite/g++.dg/cpp0x/nullptr34.C (working copy)
@@ -0,0 +1,17 @@
+// PR c++/67216
+// { dg-do compile { target c++11 } }
+
+struct s {
+ s( long ) {}
+};
+
+struct t {
+ t( void * ) {}
+};
+
+void foo(s) {}
+void foo(t) {}
+
+int main() {
+ foo(false);
+}
Index: testsuite/g++.dg/cpp0x/pr51313.C
===================================================================
--- testsuite/g++.dg/cpp0x/pr51313.C (revision 226952)
+++ testsuite/g++.dg/cpp0x/pr51313.C (working copy)
@@ -14,5 +14,5 @@ extern ostream cout;
int main()
{
- cout << isdigit(0);
+ cout << isdigit(0); // { dg-error "invalid conversion" }
}
Index: testsuite/g++.dg/warn/Wconversion2.C
===================================================================
--- testsuite/g++.dg/warn/Wconversion2.C (revision 226952)
+++ testsuite/g++.dg/warn/Wconversion2.C (working copy)
@@ -1,3 +1,4 @@
// { dg-options "-Wconversion-null" }
void foo(const char *);
-void bar() { foo(false); } // { dg-warning "pointer type for argument" }
+void bar() { foo(false); } // { dg-warning "pointer type for argument" "" { target { ! c++11 } } }
+// { dg-error "cannot convert" "" { target c++11 } 3 }
Index: testsuite/g++.dg/warn/Wnull-conversion-1.C
===================================================================
--- testsuite/g++.dg/warn/Wnull-conversion-1.C (revision 226952)
+++ testsuite/g++.dg/warn/Wnull-conversion-1.C (working copy)
@@ -6,10 +6,13 @@
void func1(int* ptr);
void func2() {
- int* t = false; // { dg-warning "converting 'false' to pointer" }
+ int* t = false; // { dg-warning "converting 'false' to pointer" "" { target { ! c++11 } } }
+// { dg-error "cannot convert" "" { target c++11 } 9 }
int* p;
- p = false; // { dg-warning "converting 'false' to pointer" }
+ p = false; // { dg-warning "converting 'false' to pointer" "" { target { ! c++11 } } }
+// { dg-error "cannot convert" "" { target c++11 } 12 }
int* r = sizeof(char) / 2; // { dg-error "invalid conversion from" "" { target c++11 } }
- func1(false); // { dg-warning "converting 'false' to pointer" }
+ func1(false); // { dg-warning "converting 'false' to pointer" "" { target { ! c++11 } } }
+// { dg-error "cannot convert" "" { target c++11 } 15 }
int i = NULL; // { dg-warning "converting to non-pointer" }
}
Index: testsuite/g++.old-deja/g++.other/null3.C
===================================================================
--- testsuite/g++.old-deja/g++.other/null3.C (revision 226952)
+++ testsuite/g++.old-deja/g++.other/null3.C (working copy)
@@ -2,5 +2,6 @@
void x()
{
- int* p = 1==0; // { dg-warning "converting 'false' to pointer" }
+ int* p = 1==0; // { dg-warning "converting 'false' to pointer" "" { target { ! c++11 } } }
+// { dg-error "cannot convert" "" { target c++11 } 5 }
}
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