diff --git a/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs b/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs
index b4ad4bf8209ec..241530db1850f 100644
--- a/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs
+++ b/crates/swc_ecma_transforms_optimization/src/simplify/expr/mod.rs
@@ -19,10 +19,6 @@ use swc_ecma_utils::{
     StringType, SymbolType, UndefinedType, Value,
     is_literal, number::JsNumber, prop_name_eq, to_int32, BoolType, ExprCtx, ExprExt, NullType,
     NumberType, ObjectType, StringType, SymbolType, UndefinedType, Value,
-    is_literal,
-    number::{ToJsInt32, ToJsUint32},
-    prop_name_eq, to_int32, BoolType, ExprCtx, ExprExt, NullType, NumberType, ObjectType,
-    StringType, SymbolType, UndefinedType, Value,
 };
 use swc_ecma_visit::{as_folder, standard_only_visit_mut, VisitMut, VisitMutWith};
 use Value::{Known, Unknown};
@@ -655,29 +651,12 @@ impl SimplifyExpr {
                         (Known(lv), Known(rv)) => (lv, rv),
                         _ => unreachable!(),
                     };
+                    let (lv, rv) = (JsNumber::from(lv), JsNumber::from(rv));
 
                     Known(match op {
-                        op!("<<") => {
-                            // https://262.ecma-international.org/5.1/#sec-11.7.1
-                            let lnum = lv.to_js_int32();
-                            let rnum = rv.to_js_uint32();
-
-                            (lnum << (rnum & 0x1f)) as f64
-                        }
-                        op!(">>") => {
-                            // https://262.ecma-international.org/5.1/#sec-11.7.2
-                            let lnum = lv.to_js_int32();
-                            let rnum = rv.to_js_uint32();
-
-                            (lnum >> (rnum & 0x1f)) as f64
-                        }
-                        op!(">>>") => {
-                            // https://262.ecma-international.org/5.1/#sec-11.7.3
-                            let lnum = lv.to_js_uint32();
-                            let rnum = rv.to_js_uint32();
-
-                            (lnum >> (rnum & 0x1f)) as f64
-                        }
+                        op!("<<") => *(lv << rv),
+                        op!(">>") => *(lv >> rv),
+                        op!(">>>") => *(lv.unsigned_shr(rv)),
 
                         _ => unreachable!("Unknown bit operator {:?}", op),
                     })
diff --git a/crates/swc_ecma_utils/src/number.rs b/crates/swc_ecma_utils/src/number.rs
index 949ac198736ce..f0a80753b65b0 100644
--- a/crates/swc_ecma_utils/src/number.rs
+++ b/crates/swc_ecma_utils/src/number.rs
@@ -95,20 +95,40 @@ impl std::ops::Deref for JsNumber {
 impl JsNumber {
     // https://tc39.es/ecma262/#sec-toint32
     fn as_int32(&self) -> i32 {
-        if !self.0.is_finite() {
+        if !self.0.is_finite() || self.0 == 0.0 {
             return 0;
         }
 
-        self.0.trunc() as i32
+        const TWO_32: f64 = u32::MAX as f64 + 1.0; // 2^32
+        const TWO_31: f64 = i32::MAX as f64 + 1.0; // 2^31
+
+        let pos_int = self.signum() * self.abs().floor();
+        let int32_bit = pos_int % TWO_32;
+
+        (if int32_bit >= TWO_31 {
+            int32_bit - TWO_32
+        } else {
+            int32_bit
+        }) as i32
     }
 
     // https://tc39.es/ecma262/#sec-touint32
     fn as_uint32(&self) -> u32 {
-        if !self.0.is_finite() {
+        if !self.0.is_finite() || self.0 == 0.0 {
             return 0;
         }
 
-        self.0.trunc() as u32
+        const TWO_32: f64 = u32::MAX as f64 + 1.0; // 2^32
+
+        let pos_int = self.signum() * self.abs().floor();
+        let result = pos_int % TWO_32;
+        // Extra step: since `x as u32` doesn't overflow, we have to add if result is
+        // negative
+        (if result < 0.0 {
+            result + TWO_32
+        } else {
+            result
+        }) as u32
     }
 }
 
@@ -349,6 +369,7 @@ mod test_js_number {
         assert_eq!(JsNumber(-0.0).as_uint32(), 0);
         assert_eq!(JsNumber(f64::INFINITY).as_uint32(), 0);
         assert_eq!(JsNumber(f64::NEG_INFINITY).as_uint32(), 0);
+        assert_eq!(JsNumber(-8.0).as_uint32(), 4294967288);
     }
 
     #[test]