diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 03da35ba1..1abb58fc5 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -542,7 +542,6 @@ std::string RTLIL::Const::decode_string() const
 	if (auto str = get_if_str())
 		return *str;
 
-	bitvectorize_internal();
 	bitvectype& bv = get_bits();
 	const int n = GetSize(bv);
 	const int n_over_8 = n / 8;
diff --git a/tests/unit/kernel/rtlilTest.cc b/tests/unit/kernel/rtlilTest.cc
index 366d022de..5f8c0dd06 100644
--- a/tests/unit/kernel/rtlilTest.cc
+++ b/tests/unit/kernel/rtlilTest.cc
@@ -131,6 +131,32 @@ namespace RTLIL {
 			EXPECT_EQ(c.as_string(), "00000010");
 			EXPECT_TRUE(c.is_str());
 		}
+
+		{
+			Const c(" ");
+			EXPECT_TRUE(c.is_str());
+			EXPECT_EQ(c.decode_string(), " ");
+			EXPECT_TRUE(c.is_str());
+		}
+
+		{
+			Const c(" ");
+			EXPECT_TRUE(c.is_str());
+			EXPECT_EQ(c.decode_string(), " ");
+			EXPECT_TRUE(c.is_str());
+		}
+
+		{
+			std::vector<State> v = {S0, S0, S0, S0, S0, S1, S0, S0};
+			Const c(v);
+			EXPECT_EQ(c.decode_string(), " ");
+		}
+
+		{
+			std::vector<State> v = {S0, S0, S0, S0, S0, S1, S0, Sx};
+			Const c(v);
+			EXPECT_EQ(c.decode_string(), " ");
+		}
 	}
 
 	TEST_F(KernelRtlilTest, ConstConstIteratorWorks) {