Eliminate intentional conversion from Smi to Int32 in HMul

test/mjsunit/smi-mul.js

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-// Flags: --allow-natives-syntax
+// Flags: --allow-natives-syntax --noalways-opt
 
-function mul(x, y) {
-  return (x * y) | 0;
+function mul(a, b) {
+    return a * b;
 }
 
-mul(0, 0);
-mul(0, 0);
+
+mul(-1, 2);
+mul(-1, 2);
 %OptimizeFunctionOnNextCall(mul);
-assertEquals(0, mul(0, -1));
+assertEquals(-2, mul(-1, 2));
 assertOptimized(mul);
 
-function div(x, y) {
-  return (x / y) | 0;
+// Deopt on minus zero.
+assertEquals(-0, mul(-1, 0));
+assertUnoptimized(mul);
+
+
+function mul2(a, b) {
+    return a * b;
 }
 
-div(4, 2);
-div(4, 2);
-%OptimizeFunctionOnNextCall(div);
-assertEquals(1, div(5, 3));
-assertOptimized(div);
+mul2(-1, 2);
+mul2(-1, 2);
+%OptimizeFunctionOnNextCall(mul2);
+
+// 2^30 is a smi boundary on arm and ia32.
+var two_30 = 1 << 30;
+// 2^31 is a smi boundary on x64.
+var two_31 = 2 * two_30;
+
+if (%IsValidSmi(two_31)) {
+  // Deopt on two_31 on x64.
+  assertEquals(two_31, mul2(-two_31, -1));
+  assertUnoptimized(mul2);
+} else {
+  // Deopt on two_30 on ia32.
+  assertEquals(two_30, mul2(-two_30, -1));
+  assertUnoptimized(mul2);
+}