diff --git a/liberty/Liberty.cc b/liberty/Liberty.cc
index 05fae172..e486915c 100644
--- a/liberty/Liberty.cc
+++ b/liberty/Liberty.cc
@@ -1896,7 +1896,7 @@ void
 LibertyCell::ensureVoltageWaveforms()
 {
   if (!have_voltage_waveforms_) {
-    float vdd;
+    float vdd = 0;
     bool vdd_exists;
     liberty_library_->supplyVoltage("VDD", vdd, vdd_exists);
     if (!vdd_exists || vdd == 0.0)