diff --git a/std/assembly/builtins.ts b/std/assembly/builtins.ts
index 74f4d7fe..12e88c5e 100644
--- a/std/assembly/builtins.ts
+++ b/std/assembly/builtins.ts
@@ -13,19 +13,11 @@ export const NaN: f64 = 0 / 0;
 export const Infinity: f64 = 1 / 0;
 
 export function isNaN<T>(value: T): bool {
-  return isFloat(value)
-    ? sizeof<T>() == 32
-      ? (reinterpret<u32>(value) & -1 >>> 1) > 0xFF << 23
-      : (reinterpret<u64>(value) & -1 >>> 1) > 0x7FF << 52
-    : false;
+  return value != value;
 }
 
 export function isFinite<T>(value: T): bool {
-  return isFloat(value)
-    ? sizeof<T>() == 32
-      ? (reinterpret<u32>(value) & -1 >>> 1) < 0xFF << 23
-      : (reinterpret<u64>(value) & -1 >>> 1) < 0x7FF << 52
-    : true;
+  return value - value == 0;
 }
 
 export declare function clz<T>(value: T): T;
diff --git a/tests/compiler/binary.optimized.wat b/tests/compiler/binary.optimized.wat
index c436e26f..c66393ed 100644
--- a/tests/compiler/binary.optimized.wat
+++ b/tests/compiler/binary.optimized.wat
@@ -1528,16 +1528,9 @@
   )
  )
  (func $isNaN<f32> (; 2 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f32.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $~lib/math/NativeMathf.mod (; 3 ;) (type $fff) (param $0 f32) (param $1 f32) (result f32)
@@ -3166,14 +3159,9 @@
   )
  )
  (func $isNaN<f64> (; 6 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f64.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $~lib/math/NativeMath.mod (; 7 ;) (type $FFF) (param $0 f64) (param $1 f64) (result f64)
diff --git a/tests/compiler/binary.untouched.wat b/tests/compiler/binary.untouched.wat
index dfb4d404..e911b771 100644
--- a/tests/compiler/binary.untouched.wat
+++ b/tests/compiler/binary.untouched.wat
@@ -4,7 +4,6 @@
  (type $FiF (func (param f64 i32) (result f64)))
  (type $fff (func (param f32 f32) (result f32)))
  (type $fi (func (param f32) (result i32)))
- (type $i (func (result i32)))
  (type $f (func (result f32)))
  (type $fif (func (param f32 i32) (result f32)))
  (type $Fi (func (param f64) (result i32)))
@@ -1721,22 +1720,9 @@
  )
  (func $isNaN<f32> (; 2 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f32.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
@@ -3624,20 +3610,9 @@
  )
  (func $isNaN<f64> (; 6 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f64.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
diff --git a/tests/compiler/builtins.optimized.wat b/tests/compiler/builtins.optimized.wat
index 01208204..56b5d946 100644
--- a/tests/compiler/builtins.optimized.wat
+++ b/tests/compiler/builtins.optimized.wat
@@ -19,51 +19,33 @@
  (export "memory" (memory $0))
  (start $start)
  (func $isNaN<f32> (; 1 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f32.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $isFinite<f32> (; 2 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.lt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
+  (f32.eq
+   (f32.sub
+    (get_local $0)
+    (get_local $0)
    )
-   (i64.const 9218868437227405312)
+   (f32.const 0)
   )
  )
  (func $isNaN<f64> (; 3 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f64.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $isFinite<f64> (; 4 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.lt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
+  (f64.eq
+   (f64.sub
+    (get_local $0)
+    (get_local $0)
    )
-   (i64.const 9218868437227405312)
+   (f64.const 0)
   )
  )
  (func $builtins/test (; 5 ;) (type $v)
diff --git a/tests/compiler/builtins.untouched.wat b/tests/compiler/builtins.untouched.wat
index 6635cde9..34e3cf48 100644
--- a/tests/compiler/builtins.untouched.wat
+++ b/tests/compiler/builtins.untouched.wat
@@ -2,8 +2,8 @@
  (type $iiiiv (func (param i32 i32 i32 i32)))
  (type $F (func (result f64)))
  (type $fi (func (param f32) (result i32)))
- (type $i (func (result i32)))
  (type $Fi (func (param f64) (result i32)))
+ (type $i (func (result i32)))
  (type $v (func))
  (type $f (func (result f32)))
  (import "env" "abort" (func $abort (param i32 i32 i32 i32)))
@@ -27,81 +27,39 @@
  (start $start)
  (func $isNaN<f32> (; 1 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f32.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
  (func $isFinite<f32> (; 2 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.lt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
+   (f32.eq
+    (f32.sub
+     (get_local $0)
+     (get_local $0)
     )
+    (f32.const 0)
    )
   )
  )
  (func $isNaN<f64> (; 3 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f64.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
  (func $isFinite<f64> (; 4 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.lt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
+   (f64.eq
+    (f64.sub
+     (get_local $0)
+     (get_local $0)
     )
+    (f64.const 0)
    )
   )
  )
diff --git a/tests/compiler/showcase.optimized.wat b/tests/compiler/showcase.optimized.wat
index e5e40f00..0ac4ddd7 100644
--- a/tests/compiler/showcase.optimized.wat
+++ b/tests/compiler/showcase.optimized.wat
@@ -1577,16 +1577,9 @@
   )
  )
  (func $isNaN<f32> (; 3 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f32.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $~lib/math/NativeMathf.mod (; 4 ;) (type $fff) (param $0 f32) (param $1 f32) (result f32)
@@ -3215,14 +3208,9 @@
   )
  )
  (func $isNaN<f64> (; 7 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f64.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $~lib/math/NativeMath.mod (; 8 ;) (type $FFF) (param $0 f64) (param $1 f64) (result f64)
@@ -3594,27 +3582,21 @@
   )
  )
  (func $isFinite<f32> (; 9 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.lt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
+  (f32.eq
+   (f32.sub
+    (get_local $0)
+    (get_local $0)
    )
-   (i64.const 9218868437227405312)
+   (f32.const 0)
   )
  )
  (func $isFinite<f64> (; 10 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.lt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
+  (f64.eq
+   (f64.sub
+    (get_local $0)
+    (get_local $0)
    )
-   (i64.const 9218868437227405312)
+   (f64.const 0)
   )
  )
  (func $showcase/ANamespace.aNamespacedFunction (; 11 ;) (type $ii) (param $0 i32) (result i32)
diff --git a/tests/compiler/showcase.untouched.wat b/tests/compiler/showcase.untouched.wat
index dde711ab..40f2ede4 100644
--- a/tests/compiler/showcase.untouched.wat
+++ b/tests/compiler/showcase.untouched.wat
@@ -4,11 +4,11 @@
  (type $FiF (func (param f64 i32) (result f64)))
  (type $fff (func (param f32 f32) (result f32)))
  (type $fi (func (param f32) (result i32)))
- (type $i (func (result i32)))
  (type $f (func (result f32)))
  (type $fif (func (param f32 i32) (result f32)))
  (type $Fi (func (param f64) (result i32)))
  (type $iiiiv (func (param i32 i32 i32 i32)))
+ (type $i (func (result i32)))
  (type $ii (func (param i32) (result i32)))
  (type $iii (func (param i32 i32) (result i32)))
  (type $v (func))
@@ -1777,22 +1777,9 @@
  )
  (func $isNaN<f32> (; 3 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f32.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
@@ -3680,20 +3667,9 @@
  )
  (func $isNaN<f64> (; 7 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f64.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
@@ -4150,41 +4126,23 @@
  )
  (func $isFinite<f32> (; 9 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.lt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
+   (f32.eq
+    (f32.sub
+     (get_local $0)
+     (get_local $0)
     )
+    (f32.const 0)
    )
   )
  )
  (func $isFinite<f64> (; 10 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.lt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
+   (f64.eq
+    (f64.sub
+     (get_local $0)
+     (get_local $0)
     )
+    (f64.const 0)
    )
   )
  )
diff --git a/tests/compiler/std/libm.optimized.wat b/tests/compiler/std/libm.optimized.wat
index 1d546330..ef3f8245 100644
--- a/tests/compiler/std/libm.optimized.wat
+++ b/tests/compiler/std/libm.optimized.wat
@@ -1308,14 +1308,9 @@
   )
  )
  (func $isNaN<f64> (; 12 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f64.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $~lib/math/NativeMath.atan (; 13 ;) (type $FF) (param $0 f64) (result f64)
diff --git a/tests/compiler/std/libm.untouched.wat b/tests/compiler/std/libm.untouched.wat
index 826d34fd..3f2239bb 100644
--- a/tests/compiler/std/libm.untouched.wat
+++ b/tests/compiler/std/libm.untouched.wat
@@ -3,8 +3,8 @@
  (type $FF (func (param f64) (result f64)))
  (type $f (func (result f32)))
  (type $Fi (func (param f64) (result i32)))
- (type $i (func (result i32)))
  (type $FFF (func (param f64 f64) (result f64)))
+ (type $i (func (result i32)))
  (type $FiF (func (param f64 i32) (result f64)))
  (type $Ff (func (param f64) (result f32)))
  (global $std/libm/E f64 (f64.const 2.718281828459045))
@@ -1557,20 +1557,9 @@
  )
  (func $isNaN<f64> (; 12 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f64.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
diff --git a/tests/compiler/std/math.optimized.wat b/tests/compiler/std/math.optimized.wat
index 3032585e..9979ded8 100644
--- a/tests/compiler/std/math.optimized.wat
+++ b/tests/compiler/std/math.optimized.wat
@@ -69,14 +69,9 @@
  (export "memory" (memory $0))
  (start $start)
  (func $isNaN<f64> (; 31 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f64.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $std/math/signbit (; 32 ;) (type $Fi) (param $0 f64) (result i32)
@@ -90,14 +85,12 @@
   )
  )
  (func $isFinite<f64> (; 33 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.lt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
+  (f64.eq
+   (f64.sub
+    (get_local $0)
+    (get_local $0)
    )
-   (i64.const 9218868437227405312)
+   (f64.const 0)
   )
  )
  (func $std/math/eulp (; 34 ;) (type $Fi) (param $0 f64) (result i32)
@@ -374,16 +367,9 @@
   (i32.const 1)
  )
  (func $isNaN<f32> (; 38 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f32.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $std/math/signbitf (; 39 ;) (type $fi) (param $0 f32) (result i32)
@@ -395,16 +381,12 @@
   )
  )
  (func $isFinite<f32> (; 40 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.lt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
+  (f32.eq
+   (f32.sub
+    (get_local $0)
+    (get_local $0)
    )
-   (i64.const 9218868437227405312)
+   (f32.const 0)
   )
  )
  (func $std/math/eulpf (; 41 ;) (type $fi) (param $0 f32) (result i32)
diff --git a/tests/compiler/std/math.untouched.wat b/tests/compiler/std/math.untouched.wat
index 571e0e6f..6cdc40a5 100644
--- a/tests/compiler/std/math.untouched.wat
+++ b/tests/compiler/std/math.untouched.wat
@@ -80,20 +80,9 @@
  (start $start)
  (func $isNaN<f64> (; 31 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f64.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
@@ -111,20 +100,12 @@
  )
  (func $isFinite<f64> (; 33 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.lt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
+   (f64.eq
+    (f64.sub
+     (get_local $0)
+     (get_local $0)
     )
+    (f64.const 0)
    )
   )
  )
@@ -427,22 +408,9 @@
  )
  (func $isNaN<f32> (; 38 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f32.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
@@ -458,22 +426,12 @@
  )
  (func $isFinite<f32> (; 40 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.lt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
+   (f32.eq
+    (f32.sub
+     (get_local $0)
+     (get_local $0)
     )
+    (f32.const 0)
    )
   )
  )
diff --git a/tests/compiler/std/mod.optimized.wat b/tests/compiler/std/mod.optimized.wat
index 0045c9de..dde4a35f 100644
--- a/tests/compiler/std/mod.optimized.wat
+++ b/tests/compiler/std/mod.optimized.wat
@@ -16,14 +16,9 @@
  (export "memory" (memory $0))
  (start $start)
  (func $isNaN<f64> (; 2 ;) (type $Fi) (param $0 f64) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (get_local $0)
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f64.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $~lib/math/NativeMath.mod (; 3 ;) (type $FFF) (param $0 f64) (param $1 f64) (result f64)
@@ -460,16 +455,9 @@
   )
  )
  (func $isNaN<f32> (; 6 ;) (type $fi) (param $0 f32) (result i32)
-  (i64.gt_u
-   (i64.and
-    (i64.reinterpret/f64
-     (f64.promote/f32
-      (get_local $0)
-     )
-    )
-    (i64.const 9223372036854775807)
-   )
-   (i64.const 9218868437227405312)
+  (f32.ne
+   (get_local $0)
+   (get_local $0)
   )
  )
  (func $~lib/math/NativeMathf.mod (; 7 ;) (type $fff) (param $0 f32) (param $1 f32) (result f32)
diff --git a/tests/compiler/std/mod.untouched.wat b/tests/compiler/std/mod.untouched.wat
index c62c572f..0db365b8 100644
--- a/tests/compiler/std/mod.untouched.wat
+++ b/tests/compiler/std/mod.untouched.wat
@@ -2,8 +2,8 @@
  (type $FFFi (func (param f64 f64 f64) (result i32)))
  (type $FFF (func (param f64 f64) (result f64)))
  (type $Fi (func (param f64) (result i32)))
- (type $i (func (result i32)))
  (type $FFi (func (param f64 f64) (result i32)))
+ (type $i (func (result i32)))
  (type $iiiiv (func (param i32 i32 i32 i32)))
  (type $F (func (result f64)))
  (type $fffi (func (param f32 f32 f32) (result i32)))
@@ -23,20 +23,9 @@
  (start $start)
  (func $isNaN<f64> (; 2 ;) (type $Fi) (param $0 f64) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (get_local $0)
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f64.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )
@@ -566,22 +555,9 @@
  )
  (func $isNaN<f32> (; 6 ;) (type $fi) (param $0 f32) (result i32)
   (return
-   (i64.gt_u
-    (i64.and
-     (i64.reinterpret/f64
-      (f64.promote/f32
-       (get_local $0)
-      )
-     )
-     (i64.shr_u
-      (i64.const -1)
-      (i64.const 1)
-     )
-    )
-    (i64.shl
-     (i64.const 2047)
-     (i64.const 52)
-    )
+   (f32.ne
+    (get_local $0)
+    (get_local $0)
    )
   )
  )