diff --git a/configure.ac b/configure.ac
index f5260a2..77f0ab5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -117,6 +117,44 @@ then
 	CFLAGS="$CFLAGS -msse2"
 fi
 
+AC_ARG_ENABLE([intfilter],
+	[AS_HELP_STRING([--enable-intfilter@<:@=(32|64|128|native)@:>@],
+		[use integers of specific size @<:@default=64@:>@ for filtering. faster but limits filter length to: 6 for 32-bit, 12 for 64-bit, 24 for 128-bit @<:@default=no@:>@])],
+	[], [enable_intfilter=no]
+)
+AC_ARG_ENABLE([intfilter32],
+	[AS_HELP_STRING([--enable-intfilter32], [deprecated. use --enable-intfilter=32 instead])],
+	[enable_intfilter=32]
+	[AC_MSG_WARN([--enable-intfilter32 option is deprecated. use --enable-intfilter=32 instead])],
+	[]
+)
+case "$enable_intfilter" in
+32)
+	intfiltertype="u32"
+	;;
+64|yes)
+	intfiltertype="u64"
+	;;
+128)
+	intfiltertype="unsigned __int128"
+	;;
+native)
+	intfiltertype="size_t"
+	;;
+no)
+	intfiltertype=""
+	;;
+*)
+	AC_MSG_WARN([unrecognised intfilter type: $enable_intfilter])
+	intfiltertype=""
+	;;
+esac
+
+if test -n "$intfiltertype"
+then
+	MYDEFS="$MYDEFS -DINTFILTER -DIFT='$intfiltertype'"
+fi
+
 cstd=""
 c99=""
 oldcflags="$CFLAGS"
@@ -135,7 +173,7 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],
     [cstd="$cstd -Wall"],
     [AC_MSG_RESULT([no])]
 )
-if test "x$c99" = "xyes" -a "x$ed25519impl" != "xdonna"
+if test "x$c99" = "xyes" -a "x$ed25519impl" != "xdonna" -a "x$enable_intfilter" != "x128"
 then
 	CFLAGS="$cstd -Wpedantic"
 	AC_MSG_CHECKING([whether CC supports -Wpedantic])
@@ -157,31 +195,6 @@ then
 fi
 CFLAGS="$oldcflags"
 
-
-AC_ARG_ENABLE([intfilter],
-	[AS_HELP_STRING([--enable-intfilter],
-		[use 64-bit integers for filtering. faster but limits filter length to 12 @<:@default=no@:>@])],
-	[], [enable_intfilter=no]
-)
-AC_ARG_ENABLE([intfilter32],
-	[AS_HELP_STRING([--enable-intfilter32],
-		[use 32-bit integers for filtering. even faster on 32-bit machines but limits filter length to 6 @<:@default=no@:>@])],
-	[], [enable_intfilter32=no]
-)
-if test "x$enable_intfilter32" = "xyes"
-then
-	if test "x$enable_intfilter" = "xyes"
-	then
-		AC_MSG_WARN([both intfilter and intfilter32 specified; using intfilter32])
-	fi
-	MYDEFS="$MYDEFS -DINTFILTER -DIFT=u32"
-else
-	if test "x$enable_intfilter" = "xyes"
-	then
-		MYDEFS="$MYDEFS -DINTFILTER"
-	fi
-fi
-
 AC_ARG_ENABLE([binfilterlen],
 	[AS_HELP_STRING([--enable-binfilterlen=VAL],
 		[set binary string filter length (if you don't use intfilter) @<:@default=32@:>@])],
diff --git a/main.c b/main.c
index f6ac23f..23f9657 100644
--- a/main.c
+++ b/main.c
@@ -76,9 +76,6 @@ struct binfilter {
 } ;
 
 #ifdef INTFILTER
-#ifndef IFT
-#define IFT u64
-#endif
 struct intfilter {
 	IFT f;
 #ifndef BINSEARCH
diff --git a/types.h b/types.h
index fe76142..10c6c70 100644
--- a/types.h
+++ b/types.h
@@ -1,16 +1,16 @@
 
-#define U64_MAX UINT64_MAX
-#define I64_MIN INT64_MIN
-#define I64_MAX INT64_MAX
-#define U32_MAX UINT32_MAX
-#define I32_MIN INT32_MIN
-#define I32_MAX INT32_MAX
-#define U16_MAX UINT16_MAX
-#define I16_MIN INT16_MIN
-#define I16_MAX INT16_MAX
 #define U8_MAX UINT8_MAX
 #define I8_MIN INT8_MIN
 #define I8_MAX INT8_MAX
+#define U16_MAX UINT16_MAX
+#define I16_MIN INT16_MIN
+#define I16_MAX INT16_MAX
+#define U32_MAX UINT32_MAX
+#define I32_MIN INT32_MIN
+#define I32_MAX INT32_MAX
+#define U64_MAX UINT64_MAX
+#define I64_MIN INT64_MIN
+#define I64_MAX INT64_MAX
 
 typedef uint8_t  u8;
 typedef  int8_t  i8;