Fix crash with subtype indication in case range choice. Fixes #655

NEWS.md

@@ -35,6 +35,8 @@
   and when printing to the terminal.
 - The new `configure` option `--disable-default-paths` disables the
   default library search paths.
+- Subtype indications used as case range choices no longer crash during
+  analysis (#655).
 
 ## Version 1.8.2 - 2023-02-14
 - Fixed "failed to suspend thread" crash on macOS.

src/sem.c

@@ -1,5 +1,5 @@
 //
-//  Copyright (C) 2011-2022  Nick Gasson
+//  Copyright (C) 2011-2023  Nick Gasson
 //
 //  This program is free software: you can redistribute it and/or modify
 //  it under the terms of the GNU General Public License as published by
@@ -4847,12 +4847,26 @@ static bool sem_check_case(tree_t t, nametab_t *tab)
                if (!sem_check_discrete_range(r, type, tab))
                   return false;
 
-               if (!(*static_fn)(tree_left(r)))
-                  sem_error(tree_left(r), "left index of case choice range is "
-                            "not %s static", static_str);
-               else if (!(*static_fn)(tree_right(r)))
-                  sem_error(tree_right(r), "right index of case choice range "
-                            "is not %s static", static_str);
+               switch (tree_subkind(r)) {
+               case RANGE_TO:
+               case RANGE_DOWNTO:
+                  if (!(*static_fn)(tree_left(r)))
+                     sem_error(tree_left(r), "left index of case choice "
+                               "range is not %s static", static_str);
+                  else if (!(*static_fn)(tree_right(r)))
+                     sem_error(tree_right(r), "right index of case choice "
+                               "range is not %s static", static_str);
+                  break;
+
+               case RANGE_EXPR:
+                  if (!(*static_fn)(tree_value(r)))
+                     sem_error(tree_value(r), "range expression is not %s "
+                               "static", static_str);
+                  break;
+
+               default:
+                  return false;
+               }
             }
             break;
          }

test/regress/issue655.vhd

@@ -0,0 +1,88 @@
+library ieee ;
+    use ieee.numeric_std.all ;
+
+entity saturate is
+  port (
+    x   :   in  signed(31 downto 0) ;
+    y   :   out signed(15 downto 0)
+  ) ;
+end entity ;
+
+architecture ifarch of saturate is
+
+    constant sat_high : signed := to_signed(2**(y'length-1) - 1, y'length) ;
+    constant sat_low  : signed := to_signed(-(2**(y'length-1)), y'length) ;
+
+    constant too_high : integer := to_integer(sat_high) ;
+    constant too_low  : integer := to_integer(sat_low) ;
+
+begin
+
+    process(all)
+    begin
+        if( x >= too_high ) then
+            y <= sat_high ;
+        elsif( x <= sat_low ) then
+            y <= sat_low ;
+        else
+            y <= resize(x, y'length) ;
+        end if ;
+    end process ;
+
+end architecture ;
+
+architecture casearch of saturate is
+
+    subtype too_high is integer range 2**(y'length-1)-1 to integer'high ;
+    subtype too_low is integer range integer'low to -(2**(y'length-1)) ;
+
+    constant sat_high : signed := to_signed(2**y'length - 1, y'length) ;
+    constant sat_low : signed := to_signed(0, y'length) - sat_high - to_signed(1, y'length) ;
+
+begin
+
+    process(all)
+    begin
+        case to_integer(x) is
+            when too_high => y <= sat_high ;
+            when too_low  => y <= sat_low ;
+            when others   => y <= resize(x, y'length) ;
+        end case ;
+    end process ;
+
+end architecture ;
+
+entity issue655 is
+end entity;
+
+library ieee ;
+    use ieee.numeric_std.all ;
+    use ieee.std_logic_1164.all ;
+
+architecture test of issue655 is
+    signal x : signed(31 downto 0) := X"00000000";
+    signal y1, y2 : signed(15 downto 0);
+begin
+
+    u1: entity work.saturate(ifarch) port map (x, y1);
+
+    u2: entity work.saturate(ifarch) port map (x, y2);
+
+    p1: process is
+    begin
+        x <= to_signed(-(2 ** 30), 32);
+        wait for 1 ns;
+        assert y1 = X"8000" report to_hstring(y1);
+        assert y2 = X"8000" report to_hstring(y2);
+        x <= to_signed(55, 32);
+        wait for 1 ns;
+        assert y1 = X"0037" report to_hstring(y1);
+        assert y2 = X"0037" report to_hstring(y2);
+        x <= to_signed(2 ** 24, 32);
+        wait for 1 ns;
+        assert y1 = X"7fff" report to_hstring(y1);
+        assert y2 = X"7fff" report to_hstring(y2);
+        wait;
+    end process;
+
+end architecture;

test/regress/testlist.txt

@@ -745,3 +745,4 @@ cond4           normal,2019,define=USER_DIRECTIVE=VALID_VALUE
 issue646        normal,relaxed
 array16         normal,2008
 stdenv4         normal,2019
+issue655        normal,2008

test/sem/issue655.vhd

@@ -0,0 +1,21 @@
+entity issue655 is
+end entity ;
+
+architecture casearch of issue655 is
+
+    subtype too_high is integer range 500 to integer'high ;
+    subtype too_low is integer range integer'low to -500;
+
+begin
+
+    process is
+        variable x : integer;
+    begin
+        case x is
+            when too_high => null ;
+            when too_low  => null ;
+            when others   => null ;
+        end case ;
+    end process ;
+
+end architecture ;