diff --git a/src/autofit/afgsub.c b/src/autofit/afgsub.c
index 6cc664ee8..386999d5c 100644
--- a/src/autofit/afgsub.c
+++ b/src/autofit/afgsub.c
@@ -649,6 +649,8 @@
     {
       FT_Error  error;
 
+      FT_UInt  real_lookupType = lookupType;
+
       FT_Byte*  subtable = table + FT_NEXT_USHORT( p );
 
 
@@ -657,11 +659,11 @@
         FT_Byte*  q = subtable + 2;
 
 
-        lookupType = FT_NEXT_USHORT( q );
-        subtable  += FT_PEEK_ULONG( q );
+        real_lookupType = FT_NEXT_USHORT( q );
+        subtable       += FT_PEEK_ULONG( q );
       }
 
-      if ( lookupType == 1 )
+      if ( real_lookupType == 1 )
       {
         FT_UInt  format = FT_PEEK_USHORT( subtable );