synth: check matching bounds for array equality. Fix #947

3 files changed, 56 insertions, 4 deletions

diff --git a/src/synth/synth-oper.adb b/src/synth/synth-oper.adb
index f2ab7cb5b..b9926aff0 100644
--- a/src/synth/synth-oper.adb
+++ b/src/synth/synth-oper.adb
@@ -419,11 +419,13 @@ package body Synth.Oper is
                return Create_Value_Discrete
                  (Boolean'Pos (Is_Equal (Left, Right)), Boolean_Type);
             end if;
-            if Is_Vector_Type (Left_Type) then
-               return Synth_Compare (Id_Eq);
-            else
-               raise Internal_Error;
+            if not Is_Matching_Bounds (Left.Typ, Right.Typ) then
+               Warning_Msg_Synth
+                 (+Expr,
+                  "length of '=' operands doesn't match, result is false");
+               return Create_Value_Discrete (0, Boolean_Type);
             end if;
+            return Synth_Compare (Id_Eq);
          when Iir_Predefined_Array_Inequality =>
             --  TODO: check size, handle non-vector.
             if Is_Vector_Type (Left_Type) then
diff --git a/src/synth/synth-values.adb b/src/synth/synth-values.adb
index c7f059c67..ed30ffd3d 100644
--- a/src/synth/synth-values.adb
+++ b/src/synth/synth-values.adb
@@ -595,6 +595,54 @@ package body Synth.Values is
       return Atype.W;
    end Get_Type_Width;
 
+   function Get_Bound_Length (L : Type_Acc; Dim : Iir_Index32) return Width is
+   begin
+      case L.Kind is
+         when Type_Vector =>
+            if Dim /= 1 then
+               raise Internal_Error;
+            end if;
+            return L.Vbound.Len;
+         when Type_Slice =>
+            if Dim /= 1 then
+               raise Internal_Error;
+            end if;
+            return L.W;
+         when Type_Array =>
+            return L.Abounds.D (Dim).Len;
+         when others =>
+            raise Internal_Error;
+      end case;
+   end Get_Bound_Length;
+
+   function Is_Matching_Bounds (L, R : Type_Acc) return Boolean is
+   begin
+      case L.Kind is
+         when Type_Bit
+           | Type_Logic
+           | Type_Discrete
+           | Type_Float =>
+            pragma Assert (L.Kind = R.Kind);
+            return True;
+         when Type_Vector
+           | Type_Slice =>
+            return Get_Bound_Length (L, 1) = Get_Bound_Length (R, 1);
+         when Type_Array =>
+            for I in L.Abounds.D'Range loop
+               if Get_Bound_Length (L, I) /= Get_Bound_Length (R, I) then
+                  return False;
+               end if;
+            end loop;
+            return True;
+         when Type_Unbounded_Array
+           | Type_Unbounded_Vector =>
+            raise Internal_Error;
+         when Type_Record =>
+            --  FIXME: handle vhdl-08
+            return True;
+      end case;
+   end Is_Matching_Bounds;
+
    function Create_Value_Default (Typ : Type_Acc) return Value_Acc is
    begin
       case Typ.Kind is
diff --git a/src/synth/synth-values.ads b/src/synth/synth-values.ads
index 73aefde2e..f897bdf8a 100644
--- a/src/synth/synth-values.ads
+++ b/src/synth/synth-values.ads
@@ -293,6 +293,8 @@ package Synth.Values is
    --  sub-elements.
    function Get_Array_Flat_Length (Typ : Type_Acc) return Width;
 
+   function Is_Matching_Bounds (L, R : Type_Acc) return Boolean;
+
    function Get_Type_Width (Atype : Type_Acc) return Width;
 
    --  Create a default initial value for TYP.