diff --git a/tgt-vhdl/vhdl_syntax.cc b/tgt-vhdl/vhdl_syntax.cc
index ae8dc2595..2e9a1dee6 100644
--- a/tgt-vhdl/vhdl_syntax.cc
+++ b/tgt-vhdl/vhdl_syntax.cc
@@ -420,11 +420,21 @@ vhdl_expr::~vhdl_expr()
  */
 vhdl_expr *vhdl_expr::cast(const vhdl_type *to)
 {
-   vhdl_fcall *conv =
-      new vhdl_fcall(to->get_string().c_str(), new vhdl_type(*to));
-   conv->add_expr(this);
-
-   return conv;
+   if (to->get_name() == type_->get_name())
+      return this;
+   else if (to->get_name() == VHDL_TYPE_BOOLEAN) {
+      // '1' is true all else are false
+      vhdl_const_bit *one = new vhdl_const_bit('1');
+      return new vhdl_binop_expr
+         (this, VHDL_BINOP_EQ, one, vhdl_type::boolean());
+   }
+   else {
+      vhdl_fcall *conv =
+         new vhdl_fcall(to->get_string().c_str(), new vhdl_type(*to));
+      conv->add_expr(this);
+      
+      return conv;
+   }
 }
 
 void vhdl_expr_list::add_expr(vhdl_expr *e)
@@ -572,6 +582,13 @@ void vhdl_assert_stmt::emit(std::ofstream &of, int level) const
    of << " report \"" << reason_ << "\" severity failure;";
 }
 
+vhdl_if_stmt::vhdl_if_stmt(vhdl_expr *test)
+{
+   // Need to ensure that the expression is Boolean
+   vhdl_type boolean(VHDL_TYPE_BOOLEAN);
+   test_ = test->cast(&boolean);
+}
+
 vhdl_if_stmt::~vhdl_if_stmt()
 {
    delete test_;
@@ -640,6 +657,9 @@ void vhdl_binop_expr::emit(std::ofstream &of, int level) const
       case VHDL_BINOP_OR:
          of << " or ";
          break;
+      case VHDL_BINOP_EQ:
+         of << " = ";
+         break;
       }
 
       (*it)->emit(of, level);
diff --git a/tgt-vhdl/vhdl_syntax.hh b/tgt-vhdl/vhdl_syntax.hh
index 52b7aee69..441c6c1bb 100644
--- a/tgt-vhdl/vhdl_syntax.hh
+++ b/tgt-vhdl/vhdl_syntax.hh
@@ -56,6 +56,7 @@ private:
 enum vhdl_binop_t {
    VHDL_BINOP_AND,
    VHDL_BINOP_OR,
+   VHDL_BINOP_EQ,
 };
 
 /*
@@ -278,8 +279,7 @@ private:
 
 class vhdl_if_stmt : public vhdl_seq_stmt {
 public:
-   vhdl_if_stmt(vhdl_expr *test)
-      : test_(test) {}
+   vhdl_if_stmt(vhdl_expr *test);
    ~vhdl_if_stmt();
 
    stmt_container *get_then_container() { return &then_part_; }
diff --git a/tgt-vhdl/vhdl_type.cc b/tgt-vhdl/vhdl_type.cc
index 374fef0ac..2aed8f44c 100644
--- a/tgt-vhdl/vhdl_type.cc
+++ b/tgt-vhdl/vhdl_type.cc
@@ -68,6 +68,8 @@ std::string vhdl_type::get_string() const
       return std::string("File");
    case VHDL_TYPE_INTEGER:
       return std::string("Integer");
+   case VHDL_TYPE_BOOLEAN:
+      return std::string("Boolean");
    default:
       return std::string("BadType");
    }