diff --git a/interpreter/binary/decode.ml b/interpreter/binary/decode.ml
index 0ff11197e..f5802555e 100644
--- a/interpreter/binary/decode.ml
+++ b/interpreter/binary/decode.ml
@@ -424,6 +424,7 @@ let simd_prefix s =
   | 0xccl -> i64x2_shr_s
   | 0xcdl -> i64x2_shr_u
   | 0xcel -> i64x2_add
+  | 0xcfl -> i64x2_all_true
   | 0xd0l -> i64x2_ne
   | 0xd1l -> i64x2_sub
   | 0xd2l -> i64x2_extmul_low_i32x4_s
diff --git a/interpreter/binary/encode.ml b/interpreter/binary/encode.ml
index 56e3d9370..63f6be418 100644
--- a/interpreter/binary/encode.ml
+++ b/interpreter/binary/encode.ml
@@ -274,6 +274,7 @@ let encode m =
       | Test (V128 V128Op.(I8x16 AllTrue)) -> simd_op 0x63l
       | Test (V128 V128Op.(I16x8 AllTrue)) -> simd_op 0x83l
       | Test (V128 V128Op.(I32x4 AllTrue)) -> simd_op 0xa3l
+      | Test (V128 V128Op.(I64x2 AllTrue)) -> simd_op 0xcfl
       | Test (V128 _) -> assert false
 
       | Compare (I32 I32Op.Eq) -> op 0x46
diff --git a/interpreter/exec/eval_simd.ml b/interpreter/exec/eval_simd.ml
index 2445f682a..7611401b7 100644
--- a/interpreter/exec/eval_simd.ml
+++ b/interpreter/exec/eval_simd.ml
@@ -187,6 +187,7 @@ module SimdOp (SXX : Simd.S) (Value : ValueType with type t = SXX.t) = struct
     | I8x16 AllTrue -> SXX.I8x16.all_true
     | I16x8 AllTrue -> SXX.I16x8.all_true
     | I32x4 AllTrue -> SXX.I32x4.all_true
+    | I64x2 AllTrue -> SXX.I64x2.all_true
     | _ -> assert false
     in fun v -> f (of_value 1 v)
 
diff --git a/interpreter/syntax/operators.ml b/interpreter/syntax/operators.ml
index e3351f844..c39efcd9c 100644
--- a/interpreter/syntax/operators.ml
+++ b/interpreter/syntax/operators.ml
@@ -410,6 +410,7 @@ let i64x2_ge_s = Binary (V128 V128Op.(I64x2 GeS))
 let i64x2_abs = Unary (V128 V128Op.(I64x2 Abs))
 let i64x2_neg = Unary (V128 V128Op.(I64x2 Neg))
 let i64x2_bitmask = SimdBitmask Simd.I64x2
+let i64x2_all_true = Test (V128 V128Op.(I64x2 AllTrue))
 let i64x2_add = Binary (V128 V128Op.(I64x2 Add))
 let i64x2_sub = Binary (V128 V128Op.(I64x2 Sub))
 let i64x2_mul = Binary (V128 V128Op.(I64x2 Mul))
diff --git a/interpreter/text/arrange.ml b/interpreter/text/arrange.ml
index 73422b6b0..86c9d62b5 100644
--- a/interpreter/text/arrange.ml
+++ b/interpreter/text/arrange.ml
@@ -194,6 +194,7 @@ struct
     | I8x16 AllTrue -> "i8x16.all_true"
     | I16x8 AllTrue -> "i16x8.all_true"
     | I32x4 AllTrue -> "i32x4.all_true"
+    | I64x2 AllTrue -> "i64x2.all_true"
     | V128 AnyTrue -> "v128.any_true"
     | _ -> assert false
 
diff --git a/interpreter/text/lexer.mll b/interpreter/text/lexer.mll
index d5f5ed121..7d1b8c83a 100644
--- a/interpreter/text/lexer.mll
+++ b/interpreter/text/lexer.mll
@@ -538,8 +538,7 @@ rule token = parse
   | "i8x16.popcnt"
     { UNARY i8x16_popcnt }
   | (simd_int_shape as s)".all_true"
-    { only ["i8x16"; "i16x8"; "i32x4"] s lexbuf;
-      UNARY (simd_int_op s i8x16_all_true i16x8_all_true i32x4_all_true unreachable) }
+    { UNARY (simd_int_op s i8x16_all_true i16x8_all_true i32x4_all_true i64x2_all_true) }
   | (simd_int_shape as s)".bitmask"
     { UNARY (simd_int_op s i8x16_bitmask i16x8_bitmask i32x4_bitmask i64x2_bitmask) }
   | (simd_int_shape as s)".shl"
diff --git a/test/core/simd/simd_boolean.wast b/test/core/simd/simd_boolean.wast
index 8eb0c8719..6ab330fe5 100644
--- a/test/core/simd/simd_boolean.wast
+++ b/test/core/simd/simd_boolean.wast
@@ -13,6 +13,7 @@
   (func (export "i32x4.all_true") (param $0 v128) (result i32) (i32x4.all_true (local.get $0)))
   (func (export "i32x4.bitmask") (param $0 v128) (result i32) (i32x4.bitmask (local.get $0)))
 
+  (func (export "i64x2.all_true") (param $0 v128) (result i32) (i64x2.all_true (local.get $0)))
   (func (export "i64x2.bitmask") (param $0 v128) (result i32) (i64x2.bitmask (local.get $0)))
 )
 
@@ -158,6 +159,25 @@
 (assert_return (invoke "i32x4.bitmask" (v128.const i32x4 -1 0 1 0xF))
                                         (i32.const 0x00000001))
 
+;; i64x2
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 0 0))
+                                        (i32.const 0))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 0 1))
+                                        (i32.const 0))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 1 0))
+                                        (i32.const 0))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 1 1))
+                                        (i32.const 1))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 -1 0))
+                                        (i32.const 0))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 0x00 0x00))
+                                        (i32.const 0))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 0xFF 0xFF))
+                                        (i32.const 1))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 0xAB 0xAB))
+                                        (i32.const 1))
+(assert_return (invoke "i64x2.all_true" (v128.const i64x2 0x55 0x55))
+                                        (i32.const 1))
 (assert_return (invoke "i64x2.bitmask" (v128.const i64x2 0xFFFFFFFF_FFFFFFFF 0xFFFFFFFF_FFFFFFFF))
                                         (i32.const 0x00000003))
 (assert_return (invoke "i64x2.bitmask" (v128.const i64x2 -1 0xF))