JS: use optimized emulation of int32 multiplication. Add test for emulated int32 multiplication

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BoxJsTestGenerated.java

@@ -6065,6 +6065,12 @@ public class BoxJsTestGenerated extends AbstractBoxJsTest {
             doTest(fileName);
         }
 
+        @TestMetadata("mulInt32.kt")
+        public void testMulInt32() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/number/mulInt32.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("numberCompareTo.kt")
         public void testNumberCompareTo() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/number/numberCompareTo.kt");

js/js.translator/testData/box/number/mulInt32.kt

@@ -0,0 +1,32 @@
+fun imul32(a: Int, b: Int): Int = js("Kotlin").imulEmulated(a, b)
+
+fun imul64(a: Int, b: Int): Int = (a.toLong() * b.toLong()).toInt()
+
+fun generateSeries(data: List<Int>): List<Pair<Int, Int>> {
+    val result = mutableListOf<Pair<Int, Int>>()
+    for (i in data.indices) {
+        for (j in i..data.lastIndex) {
+            result += Pair(data[i], data[j])
+        }
+    }
+    return result
+}
+
+fun test(series: List<Pair<Int, Int>>): String? {
+    for ((a, b) in series) {
+        (testSingle(a, b) ?: testSingle(a, -b) ?: testSingle(-a, b) ?: testSingle(-a, -b))?.let { return it }
+    }
+    return null
+}
+
+fun testSingle(a: Int, b: Int): String? {
+    var actual = imul32(a, b)
+    var expected = imul64(a, b)
+    return if (actual != expected) "$a * $b = $expected, got $actual" else null
+}
+
+fun box(): String {
+    val error = test(generateSeries(listOf(3, 0x1234, 0xFFFF, 0xABCD, 0xABCDEF, 0x43211234, 0x7FFFFFFC, 0x7FFFFFFF)))
+    if (error != null) return "fail: error"
+    return "OK"
+}

js/js.translator/testData/kotlin_lib_ecma5.js

@@ -313,11 +313,11 @@
     Kotlin.kotlinModuleMetadata = function (abiVersion, moduleName, data) {
     };
 
-    Kotlin.imul = Math.imul || function (a, b) {
+    Kotlin.imul = Math.imul || imul;
-        var ah = (a >>> 16) & 0xffff;
+
-        var al = a & 0xffff;
+    Kotlin.imulEmulated = imul;
-        var bh = (b >>> 16) & 0xffff;
+
-        var bl = b & 0xffff;
+    function imul(a, b) {
-        return ((al * bl) + (((ah * bl + al * bh) << 16) >>> 0) | 0);
+        return ((a & 0xffff0000) * (b & 0xffff) + (a & 0xffff) * (b | 0)) | 0;
-    };
+    }
 })();