diff --git a/taglib/toolkit/tbytevector.cpp b/taglib/toolkit/tbytevector.cpp
index ac32af71..4c17a739 100644
--- a/taglib/toolkit/tbytevector.cpp
+++ b/taglib/toolkit/tbytevector.cpp
@@ -746,7 +746,7 @@ ByteVector::ReverseIterator ByteVector::rbegin()
 
 ByteVector::ConstReverseIterator ByteVector::rbegin() const
 {
-#if __SUNPRO_CC >= 0x5130
+#if defined(__SUNPRO_CC) && (__SUNPRO_CC >= 0x5130)
   return ConstReverseIterator(static_cast<const char*>(&*(d->data->data.rbegin() + (d->data->data.size() - (d->offset + d->length)))));
 #else
   return d->data->data.rbegin() + (d->data->data.size() - (d->offset + d->length));
@@ -761,7 +761,7 @@ ByteVector::ReverseIterator ByteVector::rend()
 
 ByteVector::ConstReverseIterator ByteVector::rend() const
 {
-#if __SUNPRO_CC >= 0x5130
+#if defined(__SUNPRO_CC) && (__SUNPRO_CC >= 0x5130)
   return ConstReverseIterator(static_cast<const char*>(&*(d->data->data.rbegin() + (d->data->data.size() - d->offset))));
 #else
   return d->data->data.rbegin() + (d->data->data.size() - d->offset);