1 files changed, 45 insertions, 0 deletions
diff --git a/testsuite/synth/issue1978/reproducer.vhdl b/testsuite/synth/issue1978/reproducer.vhdl
new file mode 100644
index 000000000..38091541b
--- /dev/null
+++ b/testsuite/synth/issue1978/reproducer.vhdl
@@ -0,0 +1,45 @@
+--:file: Entity.vhd
+
+library IEEE;
+context IEEE.IEEE_std_context;
+
+entity Reproducer is
+  generic (
+    g_Precision : natural := 11;
+    g_PulsesPerRevolution : natural := 1000
+  );
+  port (
+    CLK : in  std_logic;
+    RST : in  std_logic;
+    EN  : in  std_logic;
+    Z   : in  std_logic;
+    POS : out unsigned(g_Precision-1 downto 0)
+  );
+end entity;
+
+architecture arch of Reproducer is
+
+  signal Position : unsigned(POS'range);
+
+  signal Direction : std_logic := '0';
+
+begin
+
+    PositionCounter: process(RST, Z, CLK)
+      constant CountLimit : unsigned(Position'range) := to_unsigned(4*g_PulsesPerRevolution-1, Position);
+    begin
+      if RST or Z then
+        Position <= (others => '0');
+      elsif rising_edge(CLK) and EN='1' then
+        Position <=
+          (others=>'0') when Position = CountLimit and Direction='1' else
+          CountLimit when Position = 0 and Direction='0' else
+          Position+1 when Direction else
+          Position-1;
+      end if;
+    end process;
+
+  pos <= position;
+  direction <= '0';
+
+end architecture;