cvt.c (cp_convert_to_pointer): Handle NULL pointer conversions, even in complex virtu...

	* cvt.c (cp_convert_to_pointer): Handle NULL pointer
	conversions, even in complex virtual base class hierarchies.

From-SVN: r21626

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index f6bc1b6..f1957d8 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+1998-08-07  Mark Mitchell  <mark@markmitchell.com>
+
+       * cvt.c (cp_convert_to_pointer): Handle a NULL pointer
+       conversions, even in complex virtual base class hierarchies.
+
 1998-08-06  Mark Mitchell  <mark@markmitchell.com>
 
        * cp-tree.h (ENUM_TEMPLATE_INFO): New macro.

diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
index 18b7d8b..1078488 100644 (file)
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -154,7 +154,15 @@ cp_convert_to_pointer (type, expr)
          && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
          && IS_AGGR_TYPE (TREE_TYPE (type))
          && IS_AGGR_TYPE (TREE_TYPE (intype))
-         && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
+         && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE
+         /* If EXPR is NULL, then we don't need to do any arithmetic
+            to convert it:
+
+              [conv.ptr]
+
+              The null pointer value is converted to the null pointer
+              value of the destination type.  */
+         && !integer_zerop (expr))
        {
          enum tree_code code = PLUS_EXPR;
          tree binfo = get_binfo (TREE_TYPE (type), TREE_TYPE (intype), 1);

diff --git a/gcc/testsuite/g++.old-deja/g++.other/cast1.C b/gcc/testsuite/g++.old-deja/g++.other/cast1.C
new file mode 100644 (file)
index 0000000..7cd8059
--- /dev/null
+++ b/gcc/testsuite/g++.old-deja/g++.other/cast1.C
@@ -0,0 +1,16 @@
+// Build don't link:
+
+struct S0 { };
+struct S1 : virtual public S0 { };
+struct S2 : virtual public S0 { };
+
+struct S3 : public S1, public S2, virtual public S0
+{
+};
+
+void f(const S0*) {}
+
+void g()
+{
+  f(static_cast<S3*>(0));
+}