Array bounds check incorrectly optimised out. Fixes #747

src/bounds.c

@@ -236,19 +236,17 @@ static void bounds_check_array_ref(tree_t t)
          type_t index_type = index_type_of(value_type, i);
          const range_kind_t dir = tree_subkind(r);
 
-         int64_t ivalue;
-         checked = folded_int(pvalue, &ivalue);
+         int64_t ivalue, low, high;
+         if (folded_int(pvalue, &ivalue) && folded_bounds(r, &low, &high)) {
+            checked = true;
 
-         int64_t low, high;
-         if (folded_bounds(r, &low, &high)) {
-            int64_t folded;
-            if (!index_in_range(pvalue, low, high, &folded)) {
+            if (ivalue < low || ivalue > high) {
                LOCAL_TEXT_BUF tb = tb_new();
                tb_cat(tb, "array");
                if (tree_kind(value) == T_REF)
                   tb_printf(tb, " %s", istr(tree_ident(value)));
                tb_cat(tb, " index ");
-               to_string(tb, index_type, folded);
+               to_string(tb, index_type, ivalue);
                tb_printf(tb, " outside of %s range ", type_pp(index_type));
                bounds_fmt_type_range(tb, index_type, dir, low, high);
 

test/regress/gold/issue747.txt

@@ -0,0 +1 @@
+(init): index 10 outside of NATURAL range 9 downto 0

test/regress/issue747.vhd

@@ -0,0 +1,21 @@
+entity issue747 is
+generic (
+    L : natural := 1
+);
+end entity;
+
+architecture test of issue747 is
+    signal s : bit_vector(L-1 downto 0);
+begin
+
+    process
+    begin
+        wait for 1 ns;
+        s(10) <= '0'; -- no check done for out of bound
+        s(12 downto 11) <= "11"; -- check is done here
+        wait for 1 ns;
+        report "SIMULATION ENDED" severity failure;
+        wait;
+    end process;
+
+end architecture;

test/regress/testlist.txt

@@ -834,3 +834,4 @@ reflect5        normal,2019
 seqblock1       normal,2019
 seqblock2       normal,2019
 stdenv6         normal,2019
+issue747        fail,gold,gL=10