diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3e0eb8c6f1..c9facbc69e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,7 @@
 - Replace ~date with ~day in Date.make\*. https://github.com/rescript-lang/rescript/pull/7324
 - Remove `-bs-jsx-mode`. https://github.com/rescript-lang/rescript/pull/7327
 - Drop Node.js version <20 support, as it is reaching End-of-Life. https://github.com/rescript-lang/rescript-compiler/pull/7354
+- Treat `int` multiplication as a normal int32 operation instead of using `Math.imul`. https://github.com/rescript-lang/rescript/pull/7358
 
 #### :house: Internal
 
diff --git a/compiler/core/js_exp_make.ml b/compiler/core/js_exp_make.ml
index 1fa740e16c..7ab4cf29b6 100644
--- a/compiler/core/js_exp_make.ml
+++ b/compiler/core/js_exp_make.ml
@@ -1607,14 +1607,8 @@ let int32_mul ?comment (e1 : J.expression) (e2 : J.expression) : J.expression =
   | {expression_desc = Number (Int {i = i0}); _}, e ->
     let i = is_pos_pow i0 in
     if i >= 0 then int32_lsl e (small_int i)
-    else
-      call ?comment ~info:Js_call_info.builtin_runtime_call
-        (dot (js_global "Math") Literals.imul)
-        [e1; e2]
-  | _ ->
-    call ?comment ~info:Js_call_info.builtin_runtime_call
-      (dot (js_global "Math") Literals.imul)
-      [e1; e2]
+    else to_int32 (float_mul ?comment e1 e2)
+  | _ -> to_int32 (float_mul ?comment e1 e2)
 
 let unchecked_int32_mul ?comment e1 e2 : J.expression =
   {comment; expression_desc = Bin (Mul, e1, e2)}
diff --git a/compiler/ext/literals.ml b/compiler/ext/literals.ml
index 34163c0c6d..9c413e7603 100644
--- a/compiler/ext/literals.ml
+++ b/compiler/ext/literals.ml
@@ -50,8 +50,6 @@ let runtime = "runtime" (* runtime directory *)
 
 let stdlib = "stdlib"
 
-let imul = "imul" (* signed int32 mul *)
-
 let setter_suffix = "#="
 
 let setter_suffix_len = String.length setter_suffix
diff --git a/lib/es6/Primitive_hash.js b/lib/es6/Primitive_hash.js
index 6807c3b44d..5a6688256a 100644
--- a/lib/es6/Primitive_hash.js
+++ b/lib/es6/Primitive_hash.js
@@ -36,7 +36,7 @@ function unsafe_pop(q) {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "Primitive_hash.res",
-      70,
+      73,
       12
     ],
     Error: new Error()
diff --git a/lib/es6/Stdlib_Int.js b/lib/es6/Stdlib_Int.js
index f8a2f4a351..873cbddf0a 100644
--- a/lib/es6/Stdlib_Int.js
+++ b/lib/es6/Stdlib_Int.js
@@ -46,7 +46,7 @@ function range(start, end, optionsOpt) {
     let range$2 = options.inclusive === true ? range$1 + 1 | 0 : range$1;
     length = Math.ceil(range$2 / abs(step)) | 0;
   }
-  return Stdlib_Array.fromInitializer(length, i => start + Math.imul(i, step) | 0);
+  return Stdlib_Array.fromInitializer(length, i => start + (i * step | 0) | 0);
 }
 
 function rangeWithOptions(start, end, options) {
diff --git a/lib/js/Primitive_hash.js b/lib/js/Primitive_hash.js
index 6ae6d31529..e501682ae1 100644
--- a/lib/js/Primitive_hash.js
+++ b/lib/js/Primitive_hash.js
@@ -36,7 +36,7 @@ function unsafe_pop(q) {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "Primitive_hash.res",
-      70,
+      73,
       12
     ],
     Error: new Error()
diff --git a/lib/js/Stdlib_Int.js b/lib/js/Stdlib_Int.js
index 44c2f7080d..8befa23d40 100644
--- a/lib/js/Stdlib_Int.js
+++ b/lib/js/Stdlib_Int.js
@@ -46,7 +46,7 @@ function range(start, end, optionsOpt) {
     let range$2 = options.inclusive === true ? range$1 + 1 | 0 : range$1;
     length = Math.ceil(range$2 / abs(step)) | 0;
   }
-  return Stdlib_Array.fromInitializer(length, i => start + Math.imul(i, step) | 0);
+  return Stdlib_Array.fromInitializer(length, i => start + (i * step | 0) | 0);
 }
 
 function rangeWithOptions(start, end, options) {
diff --git a/runtime/Primitive_hash.res b/runtime/Primitive_hash.res
index 0adc4ade6b..8cda31c764 100644
--- a/runtime/Primitive_hash.res
+++ b/runtime/Primitive_hash.res
@@ -29,6 +29,9 @@ module String = Primitive_string_extern
 
 @send external charCodeAt: (string, int) => int = "charCodeAt"
 
+// Multiply int32 with C-style overflow behavior
+external imul: (int, int) => int = "Math.imul"
+
 type rec cell<'a> = {
   content: 'a,
   mutable next: option<cell<'a>>,
@@ -85,9 +88,9 @@ let rotl32 = (x: int, n) => lor(lsl(x, n), lsr(x, 32 - n))
 
 let hash_mix_int = (h, d) => {
   let d = ref(d)
-  d.contents = d.contents * 0xcc9e2d51
+  d.contents = imul(d.contents, 0xcc9e2d51)
   d.contents = rotl32(d.contents, 15)
-  d.contents = d.contents * 0x1b873593
+  d.contents = imul(d.contents, 0x1b873593)
   let h = ref(lxor(h, d.contents))
   h.contents = rotl32(h.contents, 13)
   h.contents + lsl(h.contents, 2) + 0xe6546b64
@@ -95,9 +98,9 @@ let hash_mix_int = (h, d) => {
 
 let hash_final_mix = h => {
   let h = ref(lxor(h, lsr(h, 16)))
-  h.contents = h.contents * 0x85ebca6b
+  h.contents = imul(h.contents, 0x85ebca6b)
   h.contents = lxor(h.contents, lsr(h.contents, 13))
-  h.contents = h.contents * 0xc2b2ae35
+  h.contents = imul(h.contents, 0xc2b2ae35)
   lxor(h.contents, lsr(h.contents, 16))
 }
 
diff --git a/tests/gentype_tests/typescript-react-example/src/Records.res.js b/tests/gentype_tests/typescript-react-example/src/Records.res.js
index 66e2b276dc..5671e37021 100644
--- a/tests/gentype_tests/typescript-react-example/src/Records.res.js
+++ b/tests/gentype_tests/typescript-react-example/src/Records.res.js
@@ -6,7 +6,7 @@ import * as Belt_Option from "rescript/lib/es6/Belt_Option.js";
 import * as Primitive_option from "rescript/lib/es6/Primitive_option.js";
 
 function computeArea(param) {
-  return Math.imul(Math.imul(param.x, param.y), Belt_Option.mapWithDefault(param.z, 1, n => n));
+  return (param.x * param.y | 0) * Belt_Option.mapWithDefault(param.z, 1, n => n) | 0;
 }
 
 function coord2d(x, y) {
@@ -80,11 +80,11 @@ let someBusiness2 = {
 };
 
 function computeArea3(o) {
-  return Math.imul(Math.imul(o.x, o.y), Belt_Option.mapWithDefault(Primitive_option.fromNullable(o.z), 1, n => n));
+  return (o.x * o.y | 0) * Belt_Option.mapWithDefault(Primitive_option.fromNullable(o.z), 1, n => n) | 0;
 }
 
 function computeArea4(o) {
-  return Math.imul(Math.imul(o.x, o.y), Belt_Option.mapWithDefault(o.z, 1, n => n));
+  return (o.x * o.y | 0) * Belt_Option.mapWithDefault(o.z, 1, n => n) | 0;
 }
 
 function testMyRec(x) {
diff --git a/tests/gentype_tests/typescript-react-example/src/nested/Tuples.res.js b/tests/gentype_tests/typescript-react-example/src/nested/Tuples.res.js
index cf774aaa10..df2b77e2f4 100644
--- a/tests/gentype_tests/typescript-react-example/src/nested/Tuples.res.js
+++ b/tests/gentype_tests/typescript-react-example/src/nested/Tuples.res.js
@@ -7,15 +7,15 @@ function testTuple(param) {
 }
 
 function computeArea(param) {
-  return Math.imul(Math.imul(param[0], param[1]), Belt_Option.mapWithDefault(param[2], 1, n => n));
+  return (param[0] * param[1] | 0) * Belt_Option.mapWithDefault(param[2], 1, n => n) | 0;
 }
 
 function computeAreaWithIdent(param) {
-  return Math.imul(Math.imul(param[0], param[1]), Belt_Option.mapWithDefault(param[2], 1, n => n));
+  return (param[0] * param[1] | 0) * Belt_Option.mapWithDefault(param[2], 1, n => n) | 0;
 }
 
 function computeAreaNoConverters(param) {
-  return Math.imul(param[0], param[1]);
+  return param[0] * param[1] | 0;
 }
 
 function coord2d(x, y) {
diff --git a/tests/tests/src/a_scope_bug.mjs b/tests/tests/src/a_scope_bug.mjs
index 157799023c..aaf3201c52 100644
--- a/tests/tests/src/a_scope_bug.mjs
+++ b/tests/tests/src/a_scope_bug.mjs
@@ -4,7 +4,7 @@
 function odd(_z) {
   while (true) {
     let z = _z;
-    let even = Math.imul(z, z);
+    let even = z * z | 0;
     let a = (even + 4 | 0) + even | 0;
     console.log(a.toString());
     _z = 32;
diff --git a/tests/tests/src/bdd.mjs b/tests/tests/src/bdd.mjs
index 63e0a8bcdb..794ee5b1d2 100644
--- a/tests/tests/src/bdd.mjs
+++ b/tests/tests/src/bdd.mjs
@@ -348,7 +348,7 @@ let seed = {
 };
 
 function random() {
-  seed.contents = Math.imul(seed.contents, 25173) + 17431 | 0;
+  seed.contents = (seed.contents * 25173 | 0) + 17431 | 0;
   return (seed.contents & 1) > 0;
 }
 
diff --git a/tests/tests/src/belt_list_test.mjs b/tests/tests/src/belt_list_test.mjs
index d31ec27bb5..a3c5c28f36 100644
--- a/tests/tests/src/belt_list_test.mjs
+++ b/tests/tests/src/belt_list_test.mjs
@@ -29,8 +29,8 @@ function sum2(xs, ys) {
 
 Mocha.describe("Belt_list_test", () => {
   Mocha.test("makeBy", () => {
-    let u = Belt_List.makeBy(5, i => Math.imul(i, i));
-    let f = i => Test_utils.eq("File \"belt_list_test.res\", line 23, characters 20-27", Belt_List.getExn(u, i), Math.imul(i, i));
+    let u = Belt_List.makeBy(5, i => i * i | 0);
+    let f = i => Test_utils.eq("File \"belt_list_test.res\", line 23, characters 20-27", Belt_List.getExn(u, i), i * i | 0);
     for (let i = 0; i <= 4; ++i) {
       f(i);
     }
diff --git a/tests/tests/src/core/Core_ArrayTests.mjs b/tests/tests/src/core/Core_ArrayTests.mjs
index 88de742280..08371223f5 100644
--- a/tests/tests/src/core/Core_ArrayTests.mjs
+++ b/tests/tests/src/core/Core_ArrayTests.mjs
@@ -257,7 +257,7 @@ Test.run([
   6
 ], n => {
   if (n % 2 === 0) {
-    return Math.imul(n, n);
+    return n * n | 0;
   }
   
 }), eq, [
@@ -293,7 +293,7 @@ Test.run([
   "filterMap - empty"
 ], Stdlib_Array.filterMap([], n => {
   if (n % 2 === 0) {
-    return Math.imul(n, n);
+    return n * n | 0;
   }
   
 }), eq, []);
@@ -406,7 +406,7 @@ Test.run([
   "findMap - empty"
 ], Stdlib_Array.findMap([], n => {
   if (n % 2 === 0) {
-    return Math.imul(n, n);
+    return n * n | 0;
   }
   
 }), eq, undefined);
diff --git a/tests/tests/src/core/Core_ResultTests.mjs b/tests/tests/src/core/Core_ResultTests.mjs
index 6bb3154f2a..e47f4dcdca 100644
--- a/tests/tests/src/core/Core_ResultTests.mjs
+++ b/tests/tests/src/core/Core_ResultTests.mjs
@@ -63,7 +63,7 @@ Test.run([
 ], Stdlib_Result.mapError({
   TAG: "Ok",
   _0: 5
-}, i => Math.imul(i, 3)), eq, {
+}, i => i * 3 | 0), eq, {
   TAG: "Ok",
   _0: 5
 });
@@ -79,7 +79,7 @@ Test.run([
 ], Stdlib_Result.mapError({
   TAG: "Error",
   _0: 5
-}, i => Math.imul(i, 3)), eq, {
+}, i => i * 3 | 0), eq, {
   TAG: "Error",
   _0: 15
 });
diff --git a/tests/tests/src/dollar_escape_test.mjs b/tests/tests/src/dollar_escape_test.mjs
index 8257d45abb..98ec15d6e7 100644
--- a/tests/tests/src/dollar_escape_test.mjs
+++ b/tests/tests/src/dollar_escape_test.mjs
@@ -32,7 +32,7 @@ function $$(x, y) {
 let v = 3;
 
 function $$$plus(x, y) {
-  return Math.imul(x, y);
+  return x * y | 0;
 }
 
 let u = 3;
diff --git a/tests/tests/src/ext_pervasives_test.mjs b/tests/tests/src/ext_pervasives_test.mjs
index f15c564ef2..e1836c3740 100644
--- a/tests/tests/src/ext_pervasives_test.mjs
+++ b/tests/tests/src/ext_pervasives_test.mjs
@@ -16,7 +16,7 @@ function $$finally(v, action, f) {
 function hash_variant(s) {
   let accu = 0;
   for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
-    accu = Math.imul(223, accu) + s.codePointAt(i) | 0;
+    accu = (223 * accu | 0) + s.codePointAt(i) | 0;
   }
   accu = accu & 2147483647;
   if (accu > 1073741823) {
diff --git a/tests/tests/src/ffi_arity_test.mjs b/tests/tests/src/ffi_arity_test.mjs
index 155e3928f7..85dffafa2e 100644
--- a/tests/tests/src/ffi_arity_test.mjs
+++ b/tests/tests/src/ffi_arity_test.mjs
@@ -4,7 +4,7 @@ import * as Mt from "./mt.mjs";
 
 function f(v) {
   if (v % 2 === 0) {
-    return v => Math.imul(v, v);
+    return v => v * v | 0;
   } else {
     return v => v + v | 0;
   }
diff --git a/tests/tests/src/for_loop_test.mjs b/tests/tests/src/for_loop_test.mjs
index 773daf9f45..d5e5c3602f 100644
--- a/tests/tests/src/for_loop_test.mjs
+++ b/tests/tests/src/for_loop_test.mjs
@@ -40,7 +40,7 @@ function for_5(x, u) {
   };
   let arr = Belt_Array.map(x, param => (() => {}));
   for (let i = 0, i_finish = x.length; i < i_finish; ++i) {
-    let k = Math.imul((u << 1), u);
+    let k = (u << 1) * u | 0;
     arr[i] = () => {
       v.contents = v.contents + k | 0;
     };
@@ -68,7 +68,7 @@ function for_6(x, u) {
       contents: 0
     };
     for (let i = 0, i_finish = x.length; i < i_finish; ++i) {
-      let k = Math.imul((u << 1), u);
+      let k = (u << 1) * u | 0;
       let h = (v5.contents << 1);
       v2.contents = v2.contents + 1 | 0;
       arr[i] = () => {
@@ -93,7 +93,7 @@ function for_7() {
   let arr = Belt_Array.make(21, () => {});
   for (let i = 0; i <= 6; ++i) {
     for (let j = 0; j <= 2; ++j) {
-      arr[Math.imul(i, 3) + j | 0] = () => {
+      arr[(i * 3 | 0) + j | 0] = () => {
         v.contents = (v.contents + i | 0) + j | 0;
       };
     }
@@ -111,7 +111,7 @@ function for_8() {
     let k = (i << 1);
     for (let j = 0; j <= 2; ++j) {
       let h = i + j | 0;
-      arr[Math.imul(i, 3) + j | 0] = () => {
+      arr[(i * 3 | 0) + j | 0] = () => {
         v.contents = (((v.contents + i | 0) + j | 0) + h | 0) + k | 0;
       };
     }
diff --git a/tests/tests/src/gpr_1822_test.mjs b/tests/tests/src/gpr_1822_test.mjs
index 9706a4d490..053f75f08a 100644
--- a/tests/tests/src/gpr_1822_test.mjs
+++ b/tests/tests/src/gpr_1822_test.mjs
@@ -32,7 +32,7 @@ let myShape = {
 
 let area;
 
-area = myShape.TAG === "Circle" ? 100 * 3.14 : Math.imul(10, myShape._1);
+area = myShape.TAG === "Circle" ? 100 * 3.14 : 10 * myShape._1 | 0;
 
 eq("File \"gpr_1822_test.res\", line 23, characters 3-10", area, 314);
 
diff --git a/tests/tests/src/gpr_2413_test.mjs b/tests/tests/src/gpr_2413_test.mjs
index 1bfc18d21a..42a0ec1a93 100644
--- a/tests/tests/src/gpr_2413_test.mjs
+++ b/tests/tests/src/gpr_2413_test.mjs
@@ -16,7 +16,7 @@ function f(x) {
       break;
   }
   let a$3 = x._0._0;
-  return Math.imul(a$3, a$3);
+  return a$3 * a$3 | 0;
 }
 
 function ff(c) {
diff --git a/tests/tests/src/gpr_3536_test.mjs b/tests/tests/src/gpr_3536_test.mjs
index 052dc887ae..9aaf6cf88d 100644
--- a/tests/tests/src/gpr_3536_test.mjs
+++ b/tests/tests/src/gpr_3536_test.mjs
@@ -22,7 +22,7 @@ function xx(obj, a0, a1, a2, a3, a4, a5) {
 
 eq("File \"gpr_3536_test.res\", line 18, characters 12-19", 5, 5);
 
-eq("File \"gpr_3536_test.res\", line 20, characters 12-19", xx(3, (prim0, prim1) => prim0 - prim1 | 0, 2, (prim0, prim1) => prim0 + prim1 | 0, 4, (prim0, prim1) => Math.imul(prim0, prim1), 3), 11);
+eq("File \"gpr_3536_test.res\", line 20, characters 12-19", xx(3, (prim0, prim1) => prim0 - prim1 | 0, 2, (prim0, prim1) => prim0 + prim1 | 0, 4, (prim0, prim1) => prim0 * prim1 | 0, 3), 11);
 
 Mt.from_pair_suites("Gpr_3536_test", suites.contents);
 
diff --git a/tests/tests/src/int_overflow_test.mjs b/tests/tests/src/int_overflow_test.mjs
index 192ca3ca25..5ab54d1060 100644
--- a/tests/tests/src/int_overflow_test.mjs
+++ b/tests/tests/src/int_overflow_test.mjs
@@ -5,7 +5,7 @@ import * as Mt from "./mt.mjs";
 function hash_variant(s) {
   let accu = 0;
   for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
-    accu = Math.imul(223, accu) + s.codePointAt(i) & 2147483647;
+    accu = (223 * accu | 0) + s.codePointAt(i) & 2147483647;
   }
   if (accu > 1073741823) {
     return accu - -2147483648 | 0;
@@ -17,7 +17,7 @@ function hash_variant(s) {
 function hash_variant2(s) {
   let accu = 0;
   for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
-    accu = Math.imul(223, accu) + s.codePointAt(i) | 0;
+    accu = (223 * accu | 0) + s.codePointAt(i) | 0;
   }
   accu = accu & 2147483647;
   if (accu > 1073741823) {
diff --git a/tests/tests/src/mario_game.mjs b/tests/tests/src/mario_game.mjs
index 07016a05be..ab8da6cb66 100644
--- a/tests/tests/src/mario_game.mjs
+++ b/tests/tests/src/mario_game.mjs
@@ -1999,7 +1999,7 @@ function process_collision(dir, c1, c2, state) {
               evolve_enemy(o1.dir, typ, s2, o2, context)
             ];
           }
-          let score = Math.imul(100, state.multiplier);
+          let score = 100 * state.multiplier | 0;
           update_score(state, score);
           o2.score = score;
           state.multiplier = (state.multiplier << 1);
diff --git a/tests/tests/src/miss_colon_test.mjs b/tests/tests/src/miss_colon_test.mjs
index 1a96a1dd91..33724b26e8 100644
--- a/tests/tests/src/miss_colon_test.mjs
+++ b/tests/tests/src/miss_colon_test.mjs
@@ -55,7 +55,7 @@ function $star$colon(_f, _g) {
       if (g.TAG === "Int") {
         return {
           TAG: "Int",
-          _0: Math.imul(n, g._0)
+          _0: n * g._0 | 0
         };
       }
       if (n === 0) {
diff --git a/tests/tests/src/recursive_module_test.mjs b/tests/tests/src/recursive_module_test.mjs
index 1d2b18e5f6..e713398349 100644
--- a/tests/tests/src/recursive_module_test.mjs
+++ b/tests/tests/src/recursive_module_test.mjs
@@ -69,7 +69,7 @@ function fact(n) {
   if (n <= 1) {
     return 1;
   } else {
-    return Math.imul(n, M.fact(n - 1 | 0));
+    return n * M.fact(n - 1 | 0) | 0;
   }
 }
 
diff --git a/tests/tests/src/recursive_records_test.mjs b/tests/tests/src/recursive_records_test.mjs
index 0505ade90e..a223c082c9 100644
--- a/tests/tests/src/recursive_records_test.mjs
+++ b/tests/tests/src/recursive_records_test.mjs
@@ -25,7 +25,7 @@ rec_cell.next = rec_cell;
 function f0(x) {
   let rec_cell = {};
   Primitive_object.updateDummy(rec_cell, {
-    content: Math.imul(x, x) - 6 | 0,
+    content: (x * x | 0) - 6 | 0,
     next: rec_cell
   });
   return rec_cell;
@@ -49,7 +49,7 @@ function f2(x) {
   let rec_cell2 = {};
   Primitive_object.updateDummy(rec_cell2, {
     TAG: "Cons",
-    content: Math.imul(x, x) - 6 | 0,
+    content: (x * x | 0) - 6 | 0,
     next: rec_cell2
   });
   return rec_cell2;
@@ -93,7 +93,7 @@ rec_cell3.tl = rec_cell3;
 function f3(x) {
   let rec_cell3 = {};
   Primitive_object.updateDummy(rec_cell3, {
-    hd: Math.imul(x, x) - 6 | 0,
+    hd: (x * x | 0) - 6 | 0,
     tl: rec_cell3
   });
   return rec_cell3;
diff --git a/tests/tests/src/tagged_template_test.mjs b/tests/tests/src/tagged_template_test.mjs
index 2dbaaacc24..f3f3b66558 100644
--- a/tests/tests/src/tagged_template_test.mjs
+++ b/tests/tests/src/tagged_template_test.mjs
@@ -26,7 +26,7 @@ function foo(strings, values) {
   let res = "";
   let valueCount = values.length;
   for (let i = 0; i < valueCount; ++i) {
-    res = res + Primitive_array.get(strings, i) + Math.imul(Primitive_array.get(values, i), 10).toString();
+    res = res + Primitive_array.get(strings, i) + (Primitive_array.get(values, i) * 10 | 0).toString();
   }
   return res + Primitive_array.get(strings, valueCount);
 }
diff --git a/tests/tests/src/test_export2.mjs b/tests/tests/src/test_export2.mjs
index d3b61d62a5..e8a67959eb 100644
--- a/tests/tests/src/test_export2.mjs
+++ b/tests/tests/src/test_export2.mjs
@@ -2,7 +2,7 @@
 
 
 function f(x, y) {
-  return Math.imul(x, y);
+  return x * y | 0;
 }
 
 export {
diff --git a/tests/tests/src/test_for_loop.mjs b/tests/tests/src/test_for_loop.mjs
index c0aa40b8b7..b82b3d3f73 100644
--- a/tests/tests/src/test_for_loop.mjs
+++ b/tests/tests/src/test_for_loop.mjs
@@ -51,7 +51,7 @@ function for_5(x, u) {
   };
   let arr = Belt_Array.map(x, param => (() => {}));
   for (let i = 0, i_finish = x.length; i <= i_finish; ++i) {
-    let k = Math.imul((u << 1), u);
+    let k = (u << 1) * u | 0;
     arr[i] = () => {
       v.contents = v.contents + k | 0;
     };
@@ -78,7 +78,7 @@ function for_6(x, u) {
       contents: 0
     };
     for (let i = 0, i_finish = x.length; i <= i_finish; ++i) {
-      let k = Math.imul((u << 1), u);
+      let k = (u << 1) * u | 0;
       let h = (v5.contents << 1);
       v2.contents = v2.contents + 1 | 0;
       arr[i] = () => {
diff --git a/tests/tests/src/test_tuple.mjs b/tests/tests/src/test_tuple.mjs
index 70c8d929d9..975e54d9e4 100644
--- a/tests/tests/src/test_tuple.mjs
+++ b/tests/tests/src/test_tuple.mjs
@@ -10,9 +10,9 @@ for (let k = 1; k <= 10; ++k) {
         (i << 1)
       ] : [
         2,
-        Math.imul(i, 3)
+        i * 3 | 0
       ];
-    r = Math.imul(r, match[0]) + match[1] | 0;
+    r = (r * match[0] | 0) + match[1] | 0;
   }
 }
 
diff --git a/tests/tests/src/then_mangle_test.mjs b/tests/tests/src/then_mangle_test.mjs
index 1552358a36..33a20b3d64 100644
--- a/tests/tests/src/then_mangle_test.mjs
+++ b/tests/tests/src/then_mangle_test.mjs
@@ -16,7 +16,7 @@ function eq(loc, x, y) {
 
 function then(a, b) {
   console.log("no inline");
-  return Math.imul(a, a) + Math.imul(b, b) | 0;
+  return (a * a | 0) + (b * b | 0) | 0;
 }
 
 eq("File \"then_mangle_test.res\", line 14, characters 3-10", then(1, 2), 5);