diff --git a/.gitattributes b/.gitattributes
index 6350c3fd45..8947bea54b 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -15013,6 +15013,8 @@ tests/webtbs/tw29958.pp svneol=native#text/pascal
 tests/webtbs/tw2998.pp svneol=native#text/plain
 tests/webtbs/tw2999.pp svneol=native#text/plain
 tests/webtbs/tw29992.pp svneol=native#text/plain
+tests/webtbs/tw30035.pp svneol=native#text/plain
+tests/webtbs/tw30035a.pp svneol=native#text/plain
 tests/webtbs/tw3004.pp svneol=native#text/plain
 tests/webtbs/tw3005.pp svneol=native#text/plain
 tests/webtbs/tw3010.pp svneol=native#text/plain
diff --git a/compiler/powerpc/nppcadd.pas b/compiler/powerpc/nppcadd.pas
index e03910da28..055e530afd 100644
--- a/compiler/powerpc/nppcadd.pas
+++ b/compiler/powerpc/nppcadd.pas
@@ -485,7 +485,8 @@ interface
           end
         else
           begin
-            if is_signed(resultdef) then
+            if is_signed(left.resultdef) and
+               is_signed(right.resultdef) then
               begin
                 case nodetype of
                   addn:
diff --git a/tests/webtbs/tw30035.pp b/tests/webtbs/tw30035.pp
new file mode 100644
index 0000000000..8eb8fc06e2
--- /dev/null
+++ b/tests/webtbs/tw30035.pp
@@ -0,0 +1,14 @@
+var
+  i64: Int64;
+  qa, qb: DWord;
+begin
+  qa := 2147483648;
+  qb := 536870912;
+{$R-}{$Q-}
+  i64 := int64(qa) * int64(qb);
+  if i64 <> 1152921504606846976 then
+  begin
+    Writeln('Error!');
+    Halt(1);
+  end;
+end.
diff --git a/tests/webtbs/tw30035a.pp b/tests/webtbs/tw30035a.pp
new file mode 100644
index 0000000000..58dcc02f2c
--- /dev/null
+++ b/tests/webtbs/tw30035a.pp
@@ -0,0 +1,14 @@
+var
+  i64: Int64;
+  qa, qb: DWord;
+begin
+  qa := 2147483648;
+  qb := 536870912;
+{$R+}{$Q+}
+  i64 := int64(qa) * int64(qb);
+  if i64 <> 1152921504606846976 then
+  begin
+    Writeln('Error!');
+    Halt(1);
+  end;
+end.