3 files changed, 49 insertions, 1 deletions
diff --git a/testsuite/gna/bug21487/repro.vhdl b/testsuite/gna/bug21487/repro.vhdl
new file mode 100644
index 0000000..0da0606
--- /dev/null
+++ b/testsuite/gna/bug21487/repro.vhdl
@@ -0,0 +1,37 @@
+entity top is
+end top;
+
+use std.textio.all;
+
+architecture ARCH of TOP is
+
+  type int_vector is array (integer range<>) of integer;
+  function driver_counter( values : int_vector ) return integer is
+    variable result : integer := 1;
+    variable l: line;
+  begin
+    for index in values'range loop
+      if values(index) /= 0 then
+        result := result + values (index);
+        write (l, integer'image(values(index)) & ",");
+      end if;
+    end loop;
+    report l.all & " count resolved => " & integer'image(result);
+    return result;
+  end function;
+
+  signal S1: driver_counter integer := 6;
+
+begin
+  s1 <= 1 after 1 ns;
+
+  check: process
+  begin
+    assert s1 = 7 report "resolution function not called at init"
+      severity failure;
+    wait for 1 ns;
+    assert s1 = 2 report "resolution function not called at 1 ns"
+      severity failure;
+    wait;
+  end process;
+end architecture;
diff --git a/testsuite/gna/bug21487/testsuite.sh b/testsuite/gna/bug21487/testsuite.sh
new file mode 100755
index 0000000..df141ec
--- /dev/null
+++ b/testsuite/gna/bug21487/testsuite.sh
@@ -0,0 +1,11 @@
+#! /bin/sh
+
+. ../../testenv.sh
+
+analyze repro.vhdl
+
+elab_simulate top
+
+clean
+
+echo "Test successful"
diff --git a/translate/grt/grt-signals.adb b/translate/grt/grt-signals.adb
index 1acd675..494104f 100644
--- a/translate/grt/grt-signals.adb
+++ b/translate/grt/grt-signals.adb
@@ -3257,7 +3257,7 @@ package body Grt.Signals is
 
             when Net_One_Resolved =>
                Sig.Has_Active := True;
-               if Sig.Nbr_Ports > 0 then
+               if Sig.S.Nbr_Drivers + Sig.Nbr_Ports > 0 then
                   Compute_Resolved_Signal (Sig.S.Resolv);
                   Sig.Value := Sig.Driving_Value;
                end if;