Hi,
this wrong code PR is some sort of continuation of PR 52988, where we
discard side-effects of expression of nullptr_t. Here too, in
cp_convert_to_pointer and in build_ptrmemfunc, we don't check for
side-effects and we replace the expression with a plain int_cst or
nullptr_node. The testcase in the PR exercises only plain pointers but
we have also to handle correctly pointers to members, thus I extended it
and the patch became slightly more complex: for the case of pointer to
data member in particular I have to call by hand build2 and build a
COMPOUND_EXPR to host the side-effects (similarly to what I found used
in cp_build_addr_expr_1).
Tested x86_64-linux.
Thanks,
Paolo.
/////////////////////////////
/cp
2012-11-30 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/54170
* cvt.c (cp_convert_to_pointer): Don't discard side-effects from
expressions of nullptr_t.
* typeck.c (build_ptrmemfunc): Likewise.
/testsuite
2012-11-30 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/54170
* g++.dg/cpp0x/lambda/lambda-nullptr.C: New.
Index: cp/cvt.c
===================================================================
--- cp/cvt.c (revision 193995)
+++ cp/cvt.c (working copy)
@@ -219,10 +219,15 @@ cp_convert_to_pointer (tree type, tree expr, tsubs
{
/* A NULL pointer-to-member is represented by -1, not by
zero. */
- expr = build_int_cst_type (type, -1);
+ expr = (TREE_SIDE_EFFECTS (expr)
+ ? build2 (COMPOUND_EXPR, type, expr,
+ build_int_cst_type (type, -1))
+ : build_int_cst_type (type, -1));
}
else
- expr = build_int_cst (type, 0);
+ expr = (TREE_SIDE_EFFECTS (expr)
+ ? build_nop (type, expr)
+ : build_int_cst (type, 0));
return expr;
}
Index: cp/typeck.c
===================================================================
--- cp/typeck.c (revision 193995)
+++ cp/typeck.c (working copy)
@@ -7567,7 +7567,9 @@ build_ptrmemfunc (tree type, tree pfn, int force,
/* Handle null pointer to member function conversions. */
if (null_ptr_cst_p (pfn))
{
- pfn = build_c_cast (input_location, type, nullptr_node);
+ pfn = (TREE_SIDE_EFFECTS (pfn)
+ ? build_nop (type, pfn)
+ : build_c_cast (input_location, type, nullptr_node));
return build_ptrmemfunc1 (to_type,
integer_zero_node,
pfn);
Index: testsuite/g++.dg/cpp0x/lambda/lambda-nullptr.C
===================================================================
--- testsuite/g++.dg/cpp0x/lambda/lambda-nullptr.C (revision 0)
+++ testsuite/g++.dg/cpp0x/lambda/lambda-nullptr.C (working copy)
@@ -0,0 +1,47 @@
+// PR c++/54170
+// { dg-do run { target c++11 } }
+
+#include <cassert>
+
+struct A;
+typedef A* ptr;
+typedef int (A::*pmf) (int);
+typedef int (A::*pdm);
+
+int total;
+
+void add(int n)
+{
+ total += n;
+}
+
+template <typename RType, typename Callable>
+RType Call(Callable native_func, int arg)
+{
+ return native_func(arg);
+}
+
+template <typename RType>
+RType do_test(int delta)
+{
+ return Call<RType>([=](int delta) { add(delta); return nullptr; }, delta);
+}
+
+template <typename RType>
+void test()
+{
+ total = 0;
+ assert (!do_test<RType>(5));
+ assert (total == 5);
+ assert (!do_test<RType>(20));
+ assert (total == 25);
+ assert (!do_test<RType>(-256));
+ assert (total == -231);
+}
+
+int main()
+{
+ test<ptr>();
+ test<pdm>();
+ test<pmf>();
+}
