diff --git a/glslang/MachineIndependent/iomapper.h b/glslang/MachineIndependent/iomapper.h
index 933e259f..13a8932b 100644
--- a/glslang/MachineIndependent/iomapper.h
+++ b/glslang/MachineIndependent/iomapper.h
@@ -261,10 +261,10 @@ public:
 class TGlslIoMapper : public TIoMapper {
 public:
     TGlslIoMapper() {
-        memset(inVarMaps,     0, sizeof(TVarLiveMap*)   * (EShLangCount + 1));
-        memset(outVarMaps,    0, sizeof(TVarLiveMap*)   * (EShLangCount + 1));
-        memset(uniformVarMap, 0, sizeof(TVarLiveMap*)   * (EShLangCount + 1));
-        memset(intermediates, 0, sizeof(TIntermediate*) * (EShLangCount + 1));
+        memset(inVarMaps,     0, sizeof(TVarLiveMap*)   * EShLangCount);
+        memset(outVarMaps,    0, sizeof(TVarLiveMap*)   * EShLangCount);
+        memset(uniformVarMap, 0, sizeof(TVarLiveMap*)   * EShLangCount);
+        memset(intermediates, 0, sizeof(TIntermediate*) * EShLangCount);
     }
     virtual ~TGlslIoMapper() {
         for (size_t stage = 0; stage < EShLangCount; stage++) {